OVERVIEW OF COSMIC EVOLUTION
George V. Coyne, S.J.
Citta' del Vaticano
00120 Roma, Italy.
FAX: (06) 6988 4671
email : email@example.com
The most significant fields in the study of cosmic evolution extend over a wide range of topics including the physics of the early universe to the search for extra-solar planetary systems. In this overview I wish to emphasize two general conclusions which can be drawn from the most recent research: (1) public opinion to the contrary, our scientific knowledge of the universe is very limited; (2) there is increasing evidence that we may not be alone in the universe.
(1) By combining elementary particle physics with quantum cosmological models we have a solid understanding of the very early universe. Less well known are the epochs of the formation of structure in the universe: galaxies and clusters of galaxies. The deep field observations with the Hubble Space Telescope challenge all theories accepted to date for the development of structure. A principal difficulty is that the observations indicate that structure developed much earlier than can be accounted for in any of the expanding universe cosmologies. The detection of non-homogeneity challenges inflationary models. Despite intense efforts to determine the ultimate fate of the universe, we are more confused than ever by the discovering that the universe at large distances is accelerating. More than a decade of attempts to identify the dark matter in the universe have left us still in doubt, although the observational evidence for its existence is overwhelming.
(2) We must be very careful in our formulation of the extra-terrestrial life debate. The question to be addressed is not whether there is extraterrestrial intelligence, since there is no scientific data whereby to even approach an answer. The question is rather: Are there the physical conditions for Earthlike life elsewhere in the universe? In other words, is there any evidence that there are planets like the Earth about stars like the Sun with the macrophysical conditions for life? Research over about the past decade has led to the discovery of more than one hundred planets about other stars. These planets have been discovered by analyzing the systematic oscillations in the motion of the parent star. Only massive planets near to their parent star can be discovered in this way. Other techniques, such as high-resolution imaging in space and from the Earth, spectroscopic detection of extra-solar planetary atmospheres. etc, are being developed. Much progress is being made in the search by spectroscopy for biotic or pre-biotic conditions in extra-solar planets. Within the next decade we will undoubtedly discover hundreds more extra-solar planets. It appears, therefore, from an observational point of view, that the existence of planetary systems is a not uncommon phenomena. Do any of them nurture the physical conditions for life?
EUROPA: OVERVIEW OF FUTURE MISSIONS
Jet Propulsion Laboratory, 4800 Oak Grove Dr., Pasadena CA 91109, USA
There is significant evidence from the Galileo exploration of the Jupiter system, and other planetary studies, that the icy moons of Jupiter, Europa, Ganymede, and Callisto, have global, liquid water oceans beneath their icy crusts. These environments are critical targets for exploration related to the origin and evolution of life outside the Earth. The key ingredients for support and possibly for the origin of life as we know it liquid water, organic molecules, and energy are probably available in varying degrees on each of these bodies. Europa is particularly interesting since on this moon a global water ocean about 100 km deep may overlie a rocky, silicate mantle heated by both radioactive decay and tidal energy, raising the possibility of environments similar in many ways to terrestrial seafloor hydrothermal systems.
The US National Academy of Sciences' National Research Council has recently completed a survey of solar system exploration in the coming decade. Their recommendations include a very high priority for future exploration of Europa with a 'flagship' class Geophysical Explorer mission as well as increased emphasis on the other icy moons that may harbor sub-surface oceans. NASA has responded with a proposal for a Jupiter Icy Moon Orbiter mission that would send a spacecraft with a sophisticated payload to the Jupiter system, capable of going into orbit around each of the icy moons and conducting detailed scientific investigations. The mission concept involves use of electric powered ion-drive (pioneered for deep space use by NASA's Deep Space 1 mission) propulsion system powered by a small, highly efficient nuclear reactor. Launched with a conventional heavy-lift rocket, the spacecraft's power system would not be activated until after orbit has been achieved.
Studies of the JIMO mission are
now underway, including detailed definition of the science objectives
by a Science Definition Team. Based on a competitive selection
within the next two years, the science investigations are expected
to include geodetic and geophysical studies of the tides raised
by Jupiter, induced and intrinsic magnetic fields, detailed geologic
and geochemical mapping of the surfaces at high spatial resolution,
studies of the interactions of the satellites with the Jupiter
magnetosphere as well as studies of the Jupiter system as whole.
THE NEW UNIVERSE, DESTINY OF LIFE AND CULTURAL IMPLICATIONS
Steven J. Dick,
US Naval Observatory,
3450 Massachussetts Av.
NW, Washington, DC 20392-5420
United States of America
I intend to have a double thrust, both in the context of cosmic evolution:
1) that if cosmic evolution commonly ends in life and intelligence, this "biological universe" has many implications for our terrestrial culture(s), which I will address, and 2) that we need to take more seriously the cultural evolution component of cosmic evolution. On Earth cultural evolution totally dominates biological evolution, and in a universe where civilizations may be billions of years old, cultural evolution may have led to a "postbiological universe", dominated by artificial intelligence, with great implications for SETI. I will argue that we need to take a long-term "Stapledonian" view of cultural evolution in the universe.
ORIGIN AND EVOLUTION OF VERY EARLY SEQUENCE MOTIFS IN ENZYMES
HERRICK BALTSCHEFFSKY, BENGT PERSSON#, ANDERS SCHULTZ, JOSÉ R. PÉREZ-CASTIÑEIRA* and MARGARETA BALTSCHEFFSKY
Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, S-106 91 Stockholm, Sweden, # IFM Bioinformatics, Linköping University, S-581 83 Linköping and Centre for Genomics and Bioinformatics, Karolinska Institutet, S-171 77 Stockholm, Sweden, *Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, Spain
Conserved amino acid sequence motifs in enzymes often indicate involvement in the binding of metal ion(s) and/or in the binding and/or reactions of substrate(s). The four very early proteinaceous amino acids are glycine (G), alanine (A), aspartic acid (D) and valine (V) (Eigen and Schuster, 1979, The Hypercycle, Springer, Berlin). Aspartic acid stands out as the unique very early amino acid containing an additional, highly reactive free charge, suitable i. a. for cation binding. Active site motifs, that are rich in any or all of these four amino acids, may well be of early evolutionary significance.
Some "early" proteins appear to harbour or reflect very early sequence motifs. For example, certain enzymes involved in PPi metabolism, as well as in that of ATP, seem to be of great significance in this connection. Special attention has recently been given to the integrally membrane-bound, proton-pumping PPi synthase, which in bacterial photophosphorylation is the first and still only known alternative to the ubiquitous ATP synthase in biological electron transport coupled phosphorylation (Baltscheffsky et al. (1998) FEBS Lett. 457, 527-533). The putative active site of the PPi synthase has two nonapeptidyl sequences (DVGADLVGK and DNVGDNVGD), which are strongly conserved in the homologous enzyme family, which furthermore contain unusually many very early amino acids and which importantly have charged amino acids regularly arranged in positions 1, 5 and 9, five of these six being aspartic acid. Similar very early motifs are found in some other PPi metabolizing enzymes, and also, more or less similar, in some ATP metabolizing enzymes.
Based on plausible early motif evolution and also on results from both biochemical and geological investigations, emphasizing the emergence of selected homopolymers as probably being significant intermediate stages between monomers and heteropolymers in connection with the origin of life, a tentative, detailed outline of a stepwise molecular origin and evolution of biological energy conversion, with particular emphasis on its early phosphate metabolism, will be presented.
EANA, THE EUROPEAN EXO/ASTROBIOLOGYNETWORK ASSOCIATION
André Brack, President
Centre de biophysique moléculaire, CNRS, firstname.lastname@example.org
The European Exo/Astrobiology Network Association, EANA, was created to co-ordinate the different European centres of excellence in exo/astrobiology or related fields already organised in national networks. The specific objectives of EANA are :
- to bring together European researchers interested in exo/astrobiology programmes and to foster their cooperation
- to attract young scientists to this quickly evolving, interdisciplinary field of research
- to create a website establishing a database of expertise in different aspects of exo/astrobiology
- to interface the Network with European bodies such as ESA, ESF, the European Commission and with non European institutions active in the field
- to popularise exo/astrobiology to the public and to students.
EANA is run by an Executive Council
consisting of national members presently representing 12 European
nations active in the field (Austria, Belgium, Denmark, France,
Germany, Italy, Portugal, Spain, Sweden, Switzerland, The Netherlands,
United Kingdom) on the basis of one representative per nation,
and elected members in a number equal to the number of active
EANA is affiliated to the NASA Astrobiology Institute. The formal affiliation was signed in 2002 at the Graz Workshop by Rosalind Grymes, Deputy Director of NAI, during a reception hosted by the Governor of Styria in the historical Eggenberg Castle.
EANA is member of the International Astrobiology Circle, IAC, including the Australian Centre for Astrobiology (ACA), the Spanish Centro de Astrobiologia (CAB), the French Groupement de Recherche en Exobiologie (GDR Exobio), the American NASA Astrobiology Institute (NAI), and the United Kingdom Astrobiology Forum (UKAF). The IAC has been implemented to facilitate international exchange between established bodies dedicated to astrobiology and to harmonise the planning of joint astrobiology meetings.
Collaborative researches are developed
in the different fields covered by exo/astrobiology:
- Terrestrial life as a reference (Origins of life, environmental context, ingredients for primitive life, life in a test tube, diversity of bacterial life, life in the extremes, panspermia)
- Exploring the Solar System (Mars, Europa, Titan, Comets)
- Search for life beyond the Solar System (exoplanets, Corot and Darwin missions)
The First European Exo/Astrobiology
Workshop held in Frascati, 21-23 May 2001, was attended by 200
scientists. The national and international activities in Exo/Astrobiology
were presented, as well as the European achievements in the different
fields covered by Exo/Astrobiology. Plenary, splinter and poster
sessions cemented the European community.
The Second European Workshop on Exo/Astrobiology was organised in Graz, Austria, September 16-19, 2002. The workshop, attended by 320 participants, was oriented particularly to the planetology aspects of exo/astrobiology, in acknowledgement of the expertise of the local organisers.
Third European Exo/Astrobiology Workshop (in preparation), will be hosted by the Centro de Astrobiologia in Madrid, November 18-20, 2003.
The EANA Web Page is under construction. It will be hosted as part of the ESA pilot Virtual Institute at ESA/ESTEC in Noordwijk, The Netherlands.
SEARCH FOR LIFE ON MARS:
THE BEAGLE 2 LANDER AND THE STONE EXPERIMENT
Centre de biophysique moléculaire, CNRS, email@example.com
The search for traces of life on Mars encompasses a large number of disciplines (Brack et al., 1999; Westall et al., 2000). Beagle-2, the exobiology lander of ESA 2003 Mars Express mission, comprises an integrated suite of instruments to optimize the search for evidence of life on Mars in subsurface and rock interior samples. The package includes instruments to study sample mineralogy (composition, macroscopic and microscopic structural and textural features), organics (elemental, molecular), oxidation state and petrology (major and minor element composition). Environmental characteristics will also be measured (atmosphere, radiation budget, temperature, pressure, wind speed and direction, humidity, dust activity). The material will be sampled from protected sites (subsurface and rock interiors) with a mole and a small surface rock grinder and corer mounted on a robotic arm (Sims et al., 1999). The solid sample (soil or rock) will be heated in steps of increasing temperature, each increment being supplied with freshly generated oxygen. Any carbon compound present will burn to give carbon dioxide. The gas generated at each temperature will be analysed by the mass spectrometer. The instrument can distinguish between the two stable isotopes of the carbon and quantify the ratio. Other gases can be analysed by the same instrument including methane.
The 'STONE' experiment, flown by ESA, was designed to test whether Martian sedimentary material could survive terrestrial atmospheric entry. A basalt (inflight control), a dolomite (sedimentary rock) and artificial Martian regolith were embedded into the ablative heat shield of Foton 12, which was launched on September 1999. The collected entry samples have been analysed for their chemistry, mineralogy and isotopic compositions by a European consortium. Modifications due to atmospheric infall were tested by reference to the untreated samples. The dolomite sample was retrieved intact, although reduced to a depth of about 30% of its original thickness, suggesting that some Martian sediments could, in part, survive terrestrial atmospheric entry from space. Some kinetic isotopic fractionation accompanied the thermal degradation of the dolomite during re-entry, as evidenced by bulk isotopic measurements on different zones of the residual carbonate. The silica 'fusion crust' from the associated sample holder exhibited a significant degree of isotopic exchange with atmospheric oxygen during re-entry (Brack et al., 2002).
Brack, A., Fitton, B., Raulin,
F. (1999). Exobiology in the Solar System and the search for life
on Mars, ESA Special Publication SP 1231.
Brack, A., Baglioni, P., Borruat, G., Brandstätter, F., Demets, R., Edwards, H.G.M., Genge, M., Kurat, G., Miller, M.F., Newton, E.M., Pillinger, C.T., Roten, C.-A. and Wäsch, E. (2002). Do meteoroids of sedimentary origin survive terrestrial atmospheric entry? The ESA artificial meteorite experiment STONE, Planet. Space Science, in press.
Sims, M.R., Pillinger, C.T., Brack, A. and 26 co-auteurs (1999). Beagle 2 : a proposed exobiology lander for ESA'S 2003 Mars Express Mission, Adv. Space Res. 23, No. 11, 1925-1928.
Westall, F., Brack, A., Hofmann, B., Horneck, G., Kurat, G., Maxwell, J., Ori, G.G., Pillinger, C., Raulin, F., Thomas, N., Fitton, F., Clancy, P., Prieur, D., Vassaux, D. (2000). An ESA study for the search for life on Mars Planet. Space Sci. 48, 181-202.
EVOLUTION OF INTELLIGENT BEHAVIOR:
IS IT JUST A QUESTION OF TIME?
The Abdus Salam International Centre for Theoretical Physics
Strada Costiera 11; 34014 Trieste, Italy and
Instituto de Estudios Avanzados,
Caracas 1015A, Venezuela.
Two issues have been discussed in the past regarding the nature of biology in a universal context: (1) life may be a cosmic imperative (De Duve, 1995); (2) multicellular life may be a rare phenomenon in the cosmos, although the existence of microbial life may still be widespread (the 'Rare-Earth' hypothesis, Ward and Brownlee, 2000; Ward, 2003). We shall discuss a third issue: (3) evolution of intelligent behavior may be just a question of time (and preservation of steady planetary conditions), and hence ubiquitous in the universe. We will suggest an experimental approach to the earliest stages of the evolution of intelligent behavior. Widespread intelligence in the universe has far-reaching implications, even in the frontier with the humanities (Aretxaga, 2003; Vicuña, R. and Serani-Merlo, A., 2003). Darwin's theory of evolution is assumed to be the only theory that can adequately account for the phenomena that we associate with life anywhere in the universe (Dawkins, 1983). We argue in favor of the inevitability of the origin and evolution of life by assuming that Darwinian evolution is a universal process and that the role of contingency has to be seen beyond the restricted context of parallelism and evolutionary convergence (Akindahunsi and Chela-Flores, 2003), not only in biology, but also in other realms of science, such as in the early stages (high red-shift) of the evolution of the universe itself (Vladilo, 2003). Finally, we suggest that in the Europan Ocean, or possibly on the icy shell itself, we are presented with the problem of deciding whether some feasible experiments may throw some light on the deeper question of the eventual evolution of intelligent behavior elsewhere in the universe. We comment on some possible biosignatures of biochemical nature (Bhattacherjee and Chela-Flores, 2003) and discuss some possible ways of testing evolutionary biosignatures on or beneath the icy shell of Europa (Chela-Flores, 2003; Gatta and Chela-Flores, 2003).
Akindahunsi, A. A. and Chela-Flores, J. (2003) On the question of convergent evolution in biochemistry, in this volume.
Aretxaga, R. (2003) Astrobiology and biocentrism, in this volume.
Bhattacherjee, A. B and Chela-Flores, J. (2003) Search for bacterial waste as a possible signature of life on Europa, in this volume.
Chela-Flores, J. (2003) Testing Evolutionary Convergence on Europa. International Journal of Astrobiology (Cambridge University Press), in press.
Dawkins, R. (1983) Universal Darwinism, in Evolution from molecules to men, Bendall, D.S. (ed.),London, Cambridge University Press, pp. 403-425.
De Duve, C. (1995) Vital Dust. Life as a cosmic imperative, New York, Basic Books, A Division of HarperCollins Publishers, pp. 296-297.
Gatta, R. and Chela-Flores, J. (2003) Application of molecular biology techniques in astrobiology, in this volume.
Vicuña, R. and Serani-Merlo, A. (2003) Chance or Design in the Origin of Living Beings An epistemological point of view, in this volume.
Vladilo, G. (2003) Interstellar dust as a tracer of environments favourable to planet formation: evidence for the existence of a metallicity threshold, in this volume.
Ward, P.D. (2003) Factors leading to the appearance and survival of metazoan equivalents on habitable planets, in this volume.
Ward, P.D. and Brownlee, D. (2000)
Rare Earth: Why Complex Life is Uncommon in the Universe. Copernicus,
SEARCH FOR WATER OUTSIDE THE SOLAR SYSTEM
Istituto di Fisica dello Spazio Interplanetario
Since the first discovery of a Jupiter-mass exoplanet in 1995, a total of 101 planetary systems with 116 planets (July 2003) are known to exist around main sequence stars. Most of the detections are based on the radial velocity method which involves the measurement of the wobbling of the stars induced by the gravitational field of the orbiting giant planets. No information can be thus derived on the chemical composition of the planetary atmospheres and on the existence of terrestrial-type planets where life may evolve. The ITASEL programme (Italian Search for Extraterrestrial Life) started in 1994 after the discovery of the first water emission in the atmosphere of Jupiter induced by a cometary impact (Cosmovici et al, 1996). Our measurements have shown that the water maser line at 22 GHz can be used as a powerful diagnostic tool for planetary search outside the solar system, as comets are able to deliver very large amounts of water to planets raising the fascinating possibility of extraterrestrial life evolution. In 1999 we started the search for water in 17 different targets up to 50 light years away from the Sun by using a new developed fast multichannel spectrometer, coupled to the 32 meter dish of the Medicina radiotelescope, near Bologna, Italy. Here we report the possible detection of water emission in the atmospheres of planets orbiting Ups And, 47 CMa and Eps Eri and the work to be carried out in order to confirm and extend the discovery.
1) Cosmovici, C.B., Montebugnoli, S., Orfei, A., Pogrebenko, S. and Colom, P. (1996) "First evidence of planetary water maser emission induced by the Comet/Jupiter catastrophic impact, Planet. Space Sci, 44, 735-739
MINERAL SURFACES AS A CRADLE OF PRIMORDIAL GENETIC MATERIAL
Department of Animal Biology and Genetics, University of Florence, Florence, Italy.
Molecules which store genetic information (DNA and RNA) are central to all life on Earth. The formation of these complex molecules, and ultimately life, required specific conditions, including the synthesis and concentration of precursors (nucleotides), the joining of these monomers into larger molecules (polynucleotides), their protection in critical conditions (like those probably existing in primeval habitats), and the expression of the biological potential of the informational molecules (their capacity to multiply and evolve). Determining how these steps occurred and how the earliest genetic molecules originated on Earth is a problem that is far from being resolved.
Classical research in this field has focused on processes in aqueous solution; however it is difficult to conceive that complex molecules can be obtained by random collisions in a fully aqueous environment.
We believe that mineral surfaces, e.g. clay minerals, could have played a crucial role in the prebiotic formation of the biomolecules basic to life.
In this communication, I will discuss recent data from different fields strengthening the hypothesis, originally suggested by J.D. Bernal in 1951, of a surface-mediated origin of life.
THE LIPID WORLD: FROM CATALYTIC AND INFORMATIONAL HEAD-GROUPS TO MICELLE REPLICATION AND EVOLUTION WITHOUT NUCLEIC ACIDS
Doron Lancet, Barak Shenhav, Arren Bar-Even and Ron Kafri,
Dept. Molecular Genetics and the Crown Human Genome Center,
The Weizmann Institute of Science, Rehovot 76100, Israel.
A widespread notion is that life arose from a single molecular replicator, probably a self-copying polynucleotide in an "RNA world". We have proposed an alternative "Lipid World" scenario as an early evolutionary step in the emergence of cellular life on Earth. This concept combines the potential chemical activities of lipids and other amphiphiles, with their capacity to undergo spontaneous self-organization into supramolecular structures such as micelles and bilayers. In quantitative, chemically-realistic computer simulations of our Graded Autocatalysis Replication Domain (GARD) model, we have shown that prebiotic molecular networks, potentially existing within assemblies of lipid-like molecules, manifest a behavior similar to self reproduction or self-replication. What is being propagated is an epigenetic "compositional genome", i.e. the tally of each of the molecular species included.
In our model, lipids-like amphiphiles may possess a very large variety of chemical structures, including head-groups that resemble amino-acids or nucleotides. Catalysis is proposed to be exerted by such diverse chemical moieties, enhancing amphiphile exchange rates as well the formation of more complex head-groups with similarity to peptides or oligonucleotides. In a more recent version of our model (Polymer GARD or P-GARD), a path is delineated for the gradual transfer of from purely compositional information-storage capacity to increased dependence on linear molecular sequences. Our studies analyze in detail the properties of the emergent mutually catalytic networks within GARD assemblies, and show points of similarity and difference compared to present day cellular networks. We show that within a specific range of physicochemical interaction parameters, homeostatically stable stationary states ("composomes") emerge, capable of evolution-like progression towards higher complexity. Intriguingly, GARD may also provide a natural pathway for enantiomer selection in early biological systems.
Because amphiphile assemblies may form readily and spontaneously under prebiotic conditions, the Lipid World scenario may represent an intermediate "mesobiotic" phase, bridging an a-biotic random collection of organic molecules with a biotic protocell that contains long biopolymers, as well as more intricate information storage, catalysis and replication.
1. Segre, D., Ben-Eli, D., Deamer, D., Lancet, D. The lipid world. Origins Life Evol Biosphere, 31:119-145 (2001).
2. Segre, D., Ben-Eli, D., and Lancet, D. Compositional genomes: prebiotic information transfer in mutually catalytic non-covalent assemblies. Proc. Natl. Acad. Sci (USA) 97 (8): 4112-4117 (2000).
3. Segre, D., Shenhav, B., Kafri, R., and Lancet, D. The molecular roots of compositional inheritance. J. Theoret. Biol.. 213:481-491 (2001).
4. Shenhav, B.; Segre, D.; and Lancet, D. Mesobiotic emergence: molecular assemblies that self-replicate without biopolymers. Adv. Complex Systems 6(1): 15-35 (2003).
5. Segre, D., Lancet, D. Composing Life EMBO Reports, 1(3): 217-222 (2000).
HISTORY OF WATER ON MARS
Philippe L. Masson
Département des Sciences de la Terre
Laboratoire OrsayTerre (FRE CNRS 2566)
Bât. 509, F-91405 Orsay Cedex (France)
Besides Earth, Mars is the only planet with a record of resurfacing processes and environmental circumstances that indicate the past and possibly recent operation of hydrologic activity. However the present-day conditions on Mars are far apart of supporting liquid water on the surface. Although the large-scale morphology of the Martian channels and valleys show remarkable similarities with fluid-eroded features on Earth, there are major differences in their size, small-scale morphology, inner channel structure and source regions indicating that the erosion on Mars has its own characteristic genesis and evolution. The different landforms related to fluvial, glacial and periglacial activities, their relations with volcanism, and the chronology of water-related processes, are presented.
A warmer, wet Mars with a dense atmosphere at the time after the heavy bombardment is supposed to provide the conditions for valley formation by running water. However, recent images obtained by the MOC experiment onboard Mars Global Surveyor show relatively young small-scale alcove-like gullies combined with small channels and aprons in the walls of impact craters, thus indicating even recent groundwater seepage and probably short-term surface runoff under almost current climatic conditions.
THE ORIGIN OF BIOGENIC ELEMENTS
Dipartimento di Astronomia
Facolta' di Scienze Matematiche, Fisiche e Naturali
Universita' di Trieste, Italy
I will discuss the cosmic origin of biogenetic elements such as H, C,N,O,
Most of the elements heavier than He are produced by nuclear fusion inside
stars, whereas the light elements (H, D, He, Li)
have originated in the Big Bang.
I will review the main nuclear processes responsible for the production of
biogenic elements and discuss which stars are likely to have produced
these elements and how they have been subsequently mixed with the
interstellar medium. Finally, I will show how all of these processes
can account for the Solar System chemical composition by comparison
with models for the chemical evolution of our Galaxy, and discuss the
distribution of the biogenic elements along the disk of our Galaxy.
CURRENT STATUS OF THE SEARCH FOR EXTRASOLAR PLANETS
Geneva Observatory, Switzerland
More than hundred extrasolar planets, orbiting other solar-type stars have been discovered on the last few years. These detections are not a priori surprising for astronomers. However the orbital properties of these exoplanets are really unexpected (very short orbital period, large eccentricities and in a few cases "supermassive" planets). That observed diversity of planetary systems has forced a rediscussion of scenarios of planetary formation.
Some attention will also be given to the most recent and unbiased comparisons of chemical properties of stars ,with or without giant planets. It is also interesting to consider first results on the role of stellar multiplicity on properties of exoplanets.
The observation of a planetary transit in 1999 allows the direct measurement of the radius and mean density of an exoplanet: the direct proof that these objects are really gaseous giant planets like Saturn or Jupiter in our own Solar System. New complementary spectroscopic observations begin to reveal physical properties of the planet itself as its chemical composition and properties of its atmosphere.
More and more extrasolar planetary systems with two or three planets are discovered . A fraction of them are systems with planets on resonant orbits.
Apart from the discussion of the status of the research on exoplanets, I would present the most exciting future experiments in that field.
SPONTANEOUS GENERATION OF AMINO
IN THE INTERSTELLAR MEDIUM
Dr. Uwe Meierhenrich
D- 28359 Bremen
phone: +49-421 218 3401
In order to understand availability and distribution of molecular building blocks of biological systems during defined phases of the Chemical Evolution we studied and simulated interstellar processes in the laboratory. In dense interstellar clouds dust particles accrete ice mantles. As seen in infrared (IR) observations, this ice layer consists mainly of water ice, but also of carbon and nitrogen containing molecules. We deposited a gas mixture consisting of H2O, CO2, CO, CH3OH and NH3 onto an aluminium surface at 12 K under high vacuum, 10-7 mbar. During deposition the molecules were subjected to ultraviolet radiation with main intensity at Lyman-a. After warm-up, the refractory material was extracted from the aluminium block, hydrolysed for 24 h at 110 °C with 6 M HCl, derivatized and finally analysed by enantioselective gas chromatography coupled to a mass spectrometer. We were able to identify 16 amino acids in the room temperature products of irradiation . The results were confirmed by parallel experiments using 13C-labelled ices in order to exclude contamination. A first 'group' of the identified amino acids was suggested to serve as the precursors of peptides and proteins. A second 'group' namely the diamino carboxylic acids is assumed to contribute to the development of the first genetic material, the peptide nucleic acid PNA. Beside the two groups of amino acids, N-heterocyclic organic molecules were identified that resemble the molecular building block of biological cofactors. The obtained results support the assumption that the photochemical products could be preserved in interstellar objects, and in term be delivered to the Earth during the heavy bombardment which ended about 3.8 Gyr ago. The remaining organic molecules might have played an important role on the appearance of primitive life on Earth. The identification of amino acids in interstellar ice analogues is suggested to be linked with the prebiotic development of proteins, genetic material and biological cofactors on Earth.
 G.M. Muñoz Caro, U.J. Meierhenrich, W.A. Schutte, B. Barbier, A. Arcones Sergovia, H. Rosenbauer, W.H.-P. Thiemann, A. Brack, J.M. Greenberg: Amino acids from ultraviolet irradiation of interstellar ice analogues. Nature 416 (2002), 403-406.
RECENT ADVANCES AND SETBACKS
IN SEARCHING FOR THE OLDEST LIFE ON
EARTH A GEOLOGIST'S VIEWPOINT
Department of Earth Sciences, University of Oxford, Oxford OX1 3PR, UK
In recent technical and popular scientific literature it has become almost axiomatic to claim that life began on Earth at least 3.9 - 4.0 billion (Ga) years ago. The most intense debate on earliest life centres around early Precambrian (Archaean) rocks from West Greenland, whose exact age, field relationships to dated rocks, geological identification, mode of genesis, interpretation of trace element abundances as well as carbon-isotopic abundance ratios, are in major dispute. These topics will be briefly discussed in the talk, and it is concluded that the most strongly disputed rocks (on Akilia Island, West Greenland) contain no record of biological activity whatever. Indeed, recent work (1) demonstrates that the crucial carbon-bearing rocks on Akilia Island, identified by several workers (2,3) as chemical sediments closely related to banded iron-formation (BIF), are actually banded quartz-pyroxene rocks of mixed igneous and metasomatic parentage which have no intrinsic biological significance.
Elsewhere in West Greenland, within the 3.73.8 Ga Isua Greenstone Belt (IGB), 13C depletion in graphite particles in a genuine BIF has been claimed as evidence for biological activity (2). However, it has been shown (4) that this particular BIF was infiltrated by metasomatic carbonate fluids, in which metamorphic (thermal) disproportionation to elemental carbon has occurred. A further occurrence of IGB metamorphosed sedimentary rocks is claimed (5) to contain biogenic 13C - depleted graphite, possibly derived from the detritus of planktonic organisms. This occurrence is still under debate, but the overall evidence is highly speculative and requires much stronger evidence.
Repeated claims (e.g. 6) for 3.7 - 3.8 Ga spherical microbes in a horizon of IGB chert are implausible. These spheres occur in rocks which are extremely strongly deformed by stretching, and no spherical shape could possibly have been preserved from time of deposition. The spheres are almost certainly recent biological contaminants residing on the rock's surface and in cracks (7). Thus it is essential that all analysed ancient sedimentary rocks must be completely decontaminated from younger organisms before being tested by any technique for genuinely ancient biological activity. This is just as important for terrestrial rocks as it is for planetary samples. Indications are that such decontamination was not adequately carried out in some, or all, of the rocks discussed here.
Brief mention will be made of ongoing debate concerning the biogenicity of putative bacterial or cyanobacterial microfossils from 3.47 Ga Apex cherts in western Australia, long thought to provide the oldest morphological evidence for life on Earth (8). These microstructures have recently been reinterpreted (9) as secondary artefacts formed from amorphous graphite within multiple generations of metalliferous hydrothermal vein chert and volcanic glass, thus offering no support for primary biological morphology. Just as in Greenland (see above), a more realistic geological identification of the occurrence has cast severe doubt on the biological interpretation of these Apex chert microstructures.
Despite much effort, albeit hampered by varied geological misidentifications, there still appears to be no undisputed geological evidence for when and where life started on Earth. At any rate, popular suggestions for creation, or survival, of life in supposedly (and implausibly) sheltered environments during the putative, massive Late Heavy Bombardment of the Earth at around 3.9 4.0 Ga need no longer hold credence. We know for sure from the evidence of surviving rocks that by 3.7 3.8 Ga geological processes at and near the surface of the Earth were rapidly becoming recognisably uniformitarian, perhaps allowing life to get started in a more leisurely and unmolested fashion on mineral surfaces in Darwinian "warm little ponds".
(1) Fedo, C.M. and Whitehouse, M.J. (2002). Metasomatic origin of quartz pyroxene rock, Akilia, Greenland, and implication for Earth's earliest life. Science 296, 1448 1452.
(2) Mojzsis, S.J., Arrhenius, G., McKeegan, K.D., Harrison, T.M., Nutman, A.P. and Friend, C.R.L. 1986. Evidence for Life on Earth before 3,800 million years ago. Nature 384, 55 59.
(3) Nutman, A.P., Mojzsis, S.J. and Friend, C.R.L. 1997. Recognition of > 3850 Ma water-lain sediments in West Greenland and their significance for the early Archaean Earth. Geochim. et Cosmochim. Acta 61, 2475 2484.
(4) Van Zuilen, M.A., Lepland, A. and Arrhenius, G. 2002. Reassessing the evidence for the earliest traces of life. Nature 418, 627 630.
(5) Rosing, M.T. 1999. 13C depleted carbon microparticles in > 3700 Ma sea-floor sedimentary rocks from West Greenland. Science 283, 674 676.
(6) Pflug, H.D. 2001. Earliest organic evolution. Essay to the memory of Bartholomew Nagy. Precambrian Res. 106, 79-91.
(7) Appel, P.W.U., Moorbath, S. and Myers, J.S. 2003. Isuasphaera isua (Pflug) revisited. Precambrian Res. In press.
(8) Schopf, J.W. 1993. Microfossils of the Early Archean Apex Chert: New evidence of the antiquity of life. Science 260, 640 646.
(9) Brasier, M.D. et al. 2002. Questioning the evidence for Earth's oldest fossils. Nature 416, 76 81.
PLANETS WITH DETECTABLE LIFE
Institute for Astronomy
University of Hawaii
Honolulu, HI, USA
We now know that more than 100 planets exist around stars other than the sun. Yet it appears that only one of these planetary systems may contain a planet with detectable life. This means it could have an Earth-like planet in its habitable zone. This outcome is less disturbing than it may appear, however, given the observational difficulties for finding such systems. Using ourselves as an example, we can assess the probability that such a planet will have acquired the necessary water and biogenic elements for life to begin. We can then consider the strategies for determining whether or not life exists on that planet at the present time.
CURRENT STATUS & EXPECTED
OF THE CASSINI-HUYGENS MISSION
LISA - UMR 7583, CNRS & Universités Paris 12 et Paris 7, 61 Avenue du Général de Gaulle, 94010 Créteil Cedex France
The NASA-ESA Cassini-Huygens mission was successfully launched in October 1997. The spacecraft includes a Saturn orbiter and a Titan atmospheric probe. It has then been on an interplanetary trajectory toward Saturn. The Cassini Spacecraft flied-by Jupiter on December 2000 and will reach the Saturn system in 2004. Cassini will then become a Saturn orbiter and will fly-by its satellites, including the largest one, Titan. At the end of 2004, it will release the Huygens probe which will penetrate Titan's atmosphere on January 14, 2003. In 2000 an anomalous behavior concerning the relay link between the probe and the orbiter was identified, due to Doppler effect. It was putting into great danger the data transfer of the probe, and thus the whole Huygens probe mission. A joint ESA-NASA task force, the Huygens Rocovery Task Force was established in January 2001. The HRTF work was successfully conducted and a solution was identified, based on changing the Cassini trajectory. The trajectory now includes three new Titan fly-bys allowing to have a probe delivery at higher altitude of the orbiter, drastically reducing the Doppler effect and the resulting problem of data transfer. The Huygens mission is now safe again, as is the rest of the mission.
One of the main objectives of the Cassini-Huygens mission is to explore Titan in great detail and to study in particular the many exobiological aspects of Titan, this strange and exotic world which presents so many analogies with our planet. The Cassini orbiter and the Huygens probe, in a complementary way, will systematically study the many chemical and physical aspects of the different parts of what can be called the « geofluid » of Titan. Many of the twelve instruments of the Cassini orbiter and most of the six instruments of the Huygens probe will provide much information of crucial importance for our knowledge of the complexity of Titan's organic chemistry.
Indeed, because of the presence of a dense atmosphere, mainly made of N2 with noticeable fraction of CH4, and of an environment very rich in organics, and of many couplings involved in the various parts of its geofluid, in spite of low temperatures and the absence of liquid water, Titan is a reference for studying prebiotic chemistry on a planetary scale. Many programs have recently been developed to study in detail Titan's chemistry, in direct connection with the Cassini-Huygens mission (and even post-Cassini exploration of Titan ! !). They include new observations, development of photochemical models, laboratory determination of IR and UV spectra of organics of interest for Titan's atmosphere, and experimental studies, such as laboratory simulation of Titan's gas and aerosol organic chemistry.
The paper will present the current status of the Cassini-Huygens mission and will review the exobiological aspects of Titan. It will also present some of the new data concerning Titan's organic chemistry that have been obtained through the several possible approaches and discuss the exobiological implication of the potential scientific return of the Cassini-Huygens mission.
Coll et al, (2003), Oxirane: An exotic oxygenated organic compound in Titan? Astrophys. J, in press.
Lebreton, J.P., European Space Agency (1997). Huygens : Science, Payload and mission, ESA SP- 1177.
Lorenz, R. (2000). Post-Cassini Exploration of Titan : Science rational and mission concepts, J. Brit. Planet. Soc. 53, 218-2344.
Lorenz, R. and Mitton J. (2002).
Lifting Titan's Veil. Cambridge Univ. Press, Cambridge,
Raulin F. and T. Owen (2003). Organic chemistry and exobiology on Titan, Space Science Review., in press.
Ramirez et al, (2002). Complex Refractive Index of Titan's Aerosol Analogues in the 200-900 nm domain, Icarus, 156(2), 515-530 (2002).
VIABLE HALOBACTERIA FROM PERMIAN SALT DEPOSITS - AND IN OUTER SPACE ?
Institute of Genetics and General Biology, University of Salzburg, Hellbrunnerstr. 34, A-5020 Salzburg, Austria
From rock salt of Permo-Triassic age in an Austrian salt mine we isolated viable halophilic archaebacteria in recent years. Chemotaxonomic and molecular characterization of several strains led to their recognition as novel species. Two of those were designated Halococcus salifodinae and Halococcus dombrowskii. Several other coccoid isolates from British and German salt sediments of similar geological age proved to be members of the species H. salifodinae, as judged from their molecular, chemical and physiological properties. These microorganisms have apparently survived in the salt sediments over extremely long periods of time. Halobacteria could therefore be suitable model organisms for exploring the possibility of long-term survival of microbes on other planets. This notion appears all the more plausible since extraterrestrial halite has been detected in meteorites and is assumed to be present in the subsurface ocean on Europa. Our efforts are directed at the identification of the microbial content of ancient rock salt and the development of procedures for the investigation of the halobacterial response to extreme environmental conditions. The exploration of Mars is a target of space missions in the 21st century; therefore, testing the survival of haloarchaea under conditions comparable to present-day Mars, using a simulation chamber, was begun. Preliminary results with Halococcus and Halobacterium species suggested at least tenfold higher survival rates when cells were kept in liquid brines than under dry conditions; staining of cells with the LIFE/DEAD kit, which discriminates between damaged and intact membranes, corroborated these results.
ANCIENT LIFE ON EARTH AND MARS
1Mark A. van Zuilen, 2Aivo Lepland, 3Gustaf Arrhenius 1Centre de Recherches Pétrographiques et Géochimiques, 15 Rue Notre Dame des Pauvres, BP-20, 54501 Vandoeuvre les Nancy, France(firstname.lastname@example.org),
2Geological Survey of Norway, Leiv Eirikssonsvei 39, 7491 Trondheim, Norway, (email@example.com)
3University of California, San Diego, La Jolla CA 92093-0236, USA (firstname.lastname@example.org)
The search for signatures of extinct life on the early Earth is made difficult if not impossible due to poor preservation of the rock record. The very few exposed formations that date back beyond 3.5 Ga ago, have all been subject to high or intermediate grade metamorphism. This would have transformed the shapes of any microfossils beyond recognition, turned organic matter into kerogen and ultimately crystalline graphite. The search for life in Early Archean rocks therefore depends entirely on chemical and isotopic indicators. It is widely assumed that carbon isotope signatures of carbonaceous matter can be used to distinguish a biologic origin. However, such interpretations about ancient traces of life can only be made within the context of specific geologic circumstances requiring (1) control on recent contamination in the rock sample (is the carbonaceous material indigenous or exotic), (2) reliable protolith interpretation and control of secondary, metasomatic processes, (3) understanding of alternative abiogenic mechanisms that produce carbonaceous matter, and (4) understanding of the carbon isotopic systematics related to such processes.
A detailed study is presented of graphite occurring in different rock types in the 3.8 Ga Isua Supracrustal Belt (ISB), southern West Greenland. It will be shown that most graphite in Isua rocks is formed epigenetically either by dehydration and cooling of metamorphic fluids during serpentinization of ultramafic rocks, or by thermal disproportionation of siderite in secondary carbonate veins. Thermodynamic constraints of these processes and associated carbon isotope systematics are discussed.
The absence of an unambiguous record of life during Earth's earliest history, may be supplemented by a record of life on Mars. In the first billion years after formation this planet may have had an ocean and an active geological setting. Traces of early Martian life have been claimed in Martian meteorite ALH84001. However, it will be shown that biosignatures found in this meteorite can easily be explained by processes accompanying the thermal disproportionation of Fe-carbonates that is observed in the Isua Supracrustal Belt.
These problems, encountered with
the tracing of life in altered rocks (either meteorites from Mars
or highly metamorphosed Archean rocks), therefore highlight the
need for in-situ analysis, or sample return of potentially relatively
unaltered Martian marine or lacustrine sedimentary deposits, protected
against radiation induced oxidation in the subsurface domain.
FACTORS LEADING TO THE APPEARANCE AND SURVIVAL OF METAZOAN EQUIVALENTS ON HABITABLE PLANETS
Peter D. Ward,
Department of Biology,
The University of Washington,
Seattle, USA 98195.
There is much new evidence supporting the hypothesis that metazoan equivalents require a narrow range of environmental conditions maintained over long periods of time, and that these two factors result in there being a relatively low percentage of metazoan-bearing planets. Microbial life, on the other hand, is probably widespread in the Universe, as evidences by the presence of extremophiles in a wide range of terrestrial environments. The requirements of metazoan life may include the following. In addition to a planet residing in the Continuous Habitable Zone allowing the existence of liquid water on its surface, additional requirements might include a relatively metal-rich star, plate tectonics, and a large Jupiter-type planet in a stable orbit outboard of the habitable planet. In the case of the Earth, additional elements fostering a diverse assemblage of animals and higher plants have been the presence of a large moon, an ocean that is only partly planet-covering, a magnetic field, and a position in the galaxy ensuring an abundance of metal, but a low incidence of nearby supernovae and close stellar encounters that cause mass extinctions. It is clear that our own planet has undergone very few mass extinction episodes. Here I will examine possibilities of the origin of life not on new planets, but on planets that have undergone sterilization due to large body impact or high energy bombardment from nearby supernova or gamma ray bursts. While most models for the origin of life start with planets with early Earth conditions, there may be quite different pathways on planets that already have oxygen and abundant organic constituents from the newly deceased.
EARLY LIFE AND HYDROTHERMAL
Centre de Biophysique moléculiare
Rue Charles Sadron
45071 Orléans cedex 2,
The oldest rocks to provide information about the environment of early life, together with clear evidence of life, come from the Early Archaean greenstone terrains of Barberton in W. South Africa and the Pilbara in NW Australia. Geological investigations of these terrains document a sedimentary environment dominated by volcanic and hydrothermal (hot spring) activity that occurred both underwater and on land. Microbial mats formed at the edges of the vents and even on the cupola crowning the vent exits. Mats that formed further away from vent openings were, nevertheless, influenced by their effusions. It, thus, appears that early life on Earth was, by definition, thermophilic.
CHEMICAL EVOLUTION OF SIMPLE BIOMOLECULES IN HYDRODYNAMICALLY COLLAPSING INTERSTELLAR GAS IN PRESENCE OF GRAINS.
Centre for Space Physics
P-61 Southend Garden, Garia, Kolkata 700084, INDIA
We present time dependent results of how interstellar grains help to produce H2 molecules in the interstellar gas. We include standard size distribution of grains in our computation. We compute saturation ratio of H:H2 on grain surfaces and in gas phase respectively at various radii of a typical interstellar cloud. We then compute the time evolution of the lighter bio-molecules as a result of the hydrodynamic collapse of the cloud in presence of the grains and show that grains affect the abundances of lighter bio-molecules very significantly.
ON THE QUESTION OF CONVERGENT
EVOLUTION IN BIOCHEMISTRY
Afolabi Akintunde AKINDAHUNSI (1,2) and Julian CHELA-FLORES (3)
(1) Department of Biochemistry,
Biophysics and Macromolecular Chemistry
University of Trieste, Via Giorgieri, 1,
I-34127, Trieste, Italy
(2) Permanent Institute: Department of Biochemistry
Federal University of Technology, Akure, Nigeria
(3) The Abdus Salam ICTP, I-34014, Trieste, Italy and
Instituto de Estudios Avanzados, Caracas 1015A, Venezuela.
Since the time of Darwin, biologists have gradually learnt that convergent evolution is an ubiquitous phenomenon, since it occurs at the levels of morphology, physiology and behavior (Eisthen and Nishikawa, 2002). The case has been particularly well documented at the multicellular level. A good example is the wings of the bat, birds and those of the extinct pterodactyl. But with the advent of molecular biology in the middle of last century, evolutionary convergence (otherwise known as homoplasy) has been well documented at the microscopic level (Pace, 2001). Evolutionary convergence is significant for the central problem of astrobiology (Chela-Flores, 2003). Since all forms of life known to us are terrestrial, it is relevant to question whether the science of biology is of universal validity (Dawkins, 1983), and whether the molecular events that were precursors of the origin of life are bound to occur elsewhere in the universe wherever conditions are similar to the terrestrial ones. Natural selection, a mechanism for evolution, is a consequence of the competing drives for self-replication that are manifest in all organisms. Convergence is a significant evolutionary phenomenon, which implies a strong role for natural selection. Convergent evolution is a principle, which provides insights into biological evolution in extraterrestrial environments. It is manifest at the active sites of enzymes, in whole proteins, as well as in the genome itself. In this paper, we discuss evolutionary convergence in its classification into functional, mechanistic, structural and sequence convergence (Doolittle, 1994), which should help us in the context of astrobiology, particularly in the urgent problem of defining bioindicators that may be used in the exploration of the solar system.
Chela-Flores, J. (2003) Testing Evolutionary Convergence on Europa. International Journal of Astrobiology (Cambridge University Press), in press.
Dawkins, R. (1983) Universal Darwinism, in Evolution from molecules to men, Bendall, D.S. ed., London, Cambridge University Press, pp. 403-425.
Doolittle, R. F. (1994) Convergent evolution: the need to be explicit. Trends Biochem. Sci., 19, 15-18.
Eisthen, H.L. and Nishikawa K.C. (2002) Convergence: Obstacle or Opportunity? Brain Behav. Evol. 59 (5-6), 235-239.
Pace, N. R. (2001) The universal nature of biochemistry. Proc. Natl. Acad. Sci. USA 98, 805-808.
ASTROBIOLOGY AND BIOCENTRISM
ROBERTO ARETXAGA, Ph.D.
Philosophy Department, School of Philosophy and Educational Sciences
University of Deusto, Bilbao, Spain
The term "biocentrism" may be defined from three different perspectives: philosophical, environmental and astrobiological. Some of the main implications of the philosophical and environmental usage of the term will be considered with respect to astrobiology. In this context, biocentrism will be defined and assessed. We will also consider the impact of its decline as a result of the contributions of this new science. This will make it necessary for scientists and humanists to collaborate more if they are to approach, understand and incorporate in the best possible way the impact and consequences that the aforementioned decline is going to have on all aspects of our culture and society.
Aretxaga, R. (2003) "La ciencia astrobiológica. Un nuevo reto para el humanismo del siglo XXI". In Humanismo para el siglo XXI. Congreso Internacional (Bilbao, marzo 2003). Proceedings (CD-Rom), University of Deusto, Bilbao, 2003.
Billingham, J., Heyns, R., Milne, D., Doyle, S., Klein, M., Heilbron, J., Ashkenazi, M., Michaud, M., Lutz, J. and Shostak, S. (1994) "Social Implications of the Detection of an Extraterrestrial Civilization", SETI Press, SETI Institute, California. pp. 146.
Chela-Flores, J. (1998) "Search for the Ascent of Microbial Life towards Intelligence in the Outer Solar System". In: Origin of the life in the universe. Eds. R. Colombo, G. Giorello and E. Sindoni. Edizioni New Press: Como. pp. 143-157. Reference 32.
Chela-Flores, J. (2001) "La astrobiología, un marco para la discusión de la relación hombre-universo". Principia (Universidad Centro Occidental L. Alvarado, Barquisimeto, Venezuela), 18 (2001) pp. 12-18.
Chela-Flores, J. (2003) "Marco cultural de la astrobiología". In: "Astrobiología y Filosofía". Letras de Deusto (University of Deusto, Bilbao, Spain), Nº 98, Vol. XXXIII, enero-marzo de 2003: pp. 199-215.
Norton, Bryan G. (1984) "Environmental Ethics and Weak Anthropocentrism", Environmental Ethics 6 (1984) pp. 131-148.
Dick, S. J. (1984) Plurality of Worlds: The Origins of the Extraterrestrial Life Debate from Democritus to Kant. Cambridge University Press, 1984.
Tough, A. (2000) Workshop "When SETI Succeeds: The Impact of High-Information Contact", Foundation for the Future, Washington, USA, pp. 182.
THE DISCOVERY OF ORGANICS IN EARTH'S DEEP MATERIALS (SUB-BASEMENT RED PALEOSOLS) DRILLED IN THE NORTH PACIFIC (ODP LEG 197): IMPLICATIONS FOR ASTROBIOLOGY RESEARCH.
Rosalba Bonaccorsi (1) & Rocco L. Mancinelli (2)
(1) Dip. di Scienze Geologiche, Ambientali e Marine (DiSGAM), University of Trieste Via E. Weiss, 2 34127, TS Italy < email@example.com >
(2) SETI Institute, NASA Ames Research Center, Mail Stop 239-4, Moffett Field, CA 94035, USA <firstname.lastname@example.org>
Although the recovery of sub-basement red paleosols dates back to the 1980's [1-2], the search for organics preserved in material retrieved from such a depth has been systematically initiated during the Ocean Drilling Program (ODP) Leg 197 (Emperor Seamounts, north Pacific Transect) .
We present here evidence that the composition of organics from extremely deep soils in isolated diagenetic settings [3-4] makes them potential excellent Mars analogs . Additionally, the same samples could be used as suitable test beds to develop hypotheses for future Deep Earth biosphere research .
Identifying organics throughout earth's subsurface materials has implications relevant to Astrobiological research. In fact, the detection of organics buried deep beneath the surface of a planet is a fundamental step to constrain the presence and evolution of life on that planet. This is especially true for Mars where high near-surface UV flux, low atmospheric pressure (i.e., 4-10 mbar) and very low surface temperatures (e.g., down to -125 C) are likely to prevent the stability and flourishing of near-surface present-day life. Nevertheless, first-rate biosignatures and organics could be preserved with depth on Mars [5-6], and/or potentially (meta)stable microbial communities still be resilient at some deeper locations on the planet.
Early Eocene(?) red paleosols were cored deeply beneath volcanic basement at Site 1205 (Nintoku Seamount, 41° 20.00'N; 170° 22.70'E) and Site 1206 (Koko Seamount, 34° 55.55'N; 172° 8.75'E). These Fe oxides/oxyhydroxide-rich soil interbeds represent the weathering product (tropical conditions) of mafic igneous rocks and flood basalts (Breccia and Plagioclase-Olivine basalts) and also contain hematite, magnetite, various clay minerals and palagonite . Very importantly, they contain very low, but reliable amounts of total organic carbon (i.e., TOC = 0.12-0.01%, ± 0.02%, N = 36) [3-5] and ultra-low nitrogen (i.e., 0.01 to 0.006, N-tot wt%). Furthermore, their stable isotope signature (_13C_org = ~ -25 to ~ -26 , and negative to positive _15N_tot) would suggest mixed sources of organics (i.e., plant and primary/secondary bacterial) and microbial-induced processes (e.g., nitrogen fixation, nitrification, and denitrification). However, the existing elemental and stable isotope data-set [3-4] need to be compared with results obtained from standard microbiological techniques in order to establish the potential for those Eocene soils to serve as a suitable analog for a possible Mars near-surface to deep biosphere .
More specifically: a) Preservation of organic traces in a deep earth system (no sun light, and reducing conditions) which remained isolated and decoupled from the ocean and the atmosphere for millions of years. b) The soil sequences are difficult to access (they are deeply buried -300 to -350 metres below volcanic basement, [e.g., 3]) and sample (only from deep drilling; eg., ), and thus relatively rare in geologic collections. c) The soil samples underwent initial heating by overrunning lava flows that may have partially altered/destroyed their original composition (e.g., organics and former microbial communities) throughout . These heating effects could be understood on those soil samples and then applied to Mars.
Finally, integrating microbial ecological and geochemical studies on the ODP soil samples to develop a model for understanding what types of organic material may serve as potential biomarkers for a future Mars deep drilling project. This combination would indeed, would help shape future exploration and deep to near-surface drilling missions (i.e., soils sampling during landed missions) on Mars .
 Karpoff, A.M., 1980. Init. Repts. DSDP, 55: Washington, 707-711.  Shipboard Scientific Party, 1993a Site 871, Proc. ODP, Init. Repts. 144: College Station, TX (Ocean Drilling Program), 41-103.  Tarduno, J.A., et al., 2002. Proc. ODP, Init. Repts., 197 [Online]: http://www-odp.tamu.edu/publications/197_IR/197ir.htm.  Bonaccorsi, R., 2002. EOS Trans AGU, 83(47), Fall Meet. Suppl. Abstract.  Bonaccorsi, R., et al., 2002 Bioastronomy 2002: Life Among The Stars Conference, 8-12 July 2002, Great Barrier Reef, Australia]. (Abstract).  Kanavarioti, A, and Mancinelli, R.L. 1990. Icarus. 84:196-202.  http://www.iodp.org:16080/iwg.  Mancinelli, R.L, 2000. Accessing the Martian deep sub-surface to search for life. Planet. Space Sci., 48:1035-1043.
EXPERIMENTAL STUDY OF THE DEGRADATION OF COMPLEX ORGANIC MOLECULES. APPLICATION TO THE ORIGIN OF EXTENDED SOURCES IN COMETARY ATMOSPHERES.
Fray N., Bénilan Y., Cottin H., Gazeau M.-C., and Raulin F.
LISA, UMR 7583, Universités Paris 7 and Paris 12
email@example.com / Fax : 33-(0)18.104.22.168.68
Some molecules or radicals observed in cometary atmospheres present so-called "extended sources". It means that their distribution in comae cannot be explained by a direct sublimation from the nucleus, but rather by a production in the coma. The origin of those extended sources is still an unsolved question.
Some complex organic molecules, like HCN polymers, HMT (C6H12N4) or polyoxymethylene [formaldehyde polymers: (-CH2-O-)n], are sometime evoked as possible parents for the extended sources of CN and H2CO respectively. These polymers in solid state on cometary grains could release volatiles through thermal and photolytic degradation.
We have developed an experimental program in order to study the chemical reactions of degradation of solid polymers by UV irradiation and heat. The production of resulting small gaseous molecules is studied through MS, GC and IR analyses and provide identification of the degradation products and the determination of the photo-degradation quantum yields or the thermal degradation kinetics. Those fundamental data are then included into a model of the outer coma in order to interpret observations.
We will present our latest results on the degradation of HCN polymers, HMT and polyoxymethylene. We show that the degradation of organic polymers is a possible source of molecules and radicals which present an extended source. And thus we can infer the presence of complex organics in the nucleus from the modelling of the extended source phenomenon.
OBSERVATION, MODELING AND EXPERIMENTAL SIMULATION : UNDERSTANDING TITAN'S ATMOSPHERIC CHEMISTRY USING THESE THREE TOOLS
J.-M. Bernard (1) , P. Coll (1) , A. Jolly (1) , Y. Bénilan (1) , G. Cernogora (2) , C.D. Pintassilgo (3) , F. Raulin (1)
(1) LISA, UMR 7583, France, e-mail: firstname.lastname@example.org
(2) S.A., UMR 7620, France
(3) Centro de Fisica dos Plasmas and Departamento de Fisica, Lisboa, Portugal
Since several years, Titan, the largest satellite of Saturn, is studied like an exo/astrobiological object. Its dense atmosphere is made of nitrogen and a few percent of methane. Since Miller's experiment, we know that N2/CH4 atmospheres have a strong interest for prebiotic organic chemistry. Under the energetic particles (coming from solar radiations and Saturn magnetosphere), both hydrocarbons, nitriles (like HCN, precursor of amino-acids) and aerosols are produced in notable amounts.
However, the chemistry of this object is very difficult to understand. The coupling between modeling, experimental simulations and observations allows to have a better knowledge about this satellite.
At LISA, in France, the atmospheric chemistry on Titan is reproduced during laboratory simulation experiments since several years. In order to simulate as well as possible Titan's atmosphere, these simulations are done by initiating a glow discharge in a continuously flowing N2/CH4 mixture at low temperature. Aerosols, gas, radicals and ions produced in the reactor can be analyzed by different techniques.
First I will describe the experimental simulation. Next I will present the latest results about this experimental simulation and their implications on modeling and observations.
SEARCH FOR BACTERIAL WASTE AS A POSSIBLE SIGNATURE OF LIFE ON EUROPA
Aranya B Bhattacherjee*
INFM, Dipartimento di Fisica E.Fermi, Universita di Pisa, Via Buonarroti 2, I-56127, Pisa, Italy
The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy and Instituto de Estudios Avanzados, Caracas 1015A, Venezuela.
* Permanent Institute: Department of Physics, A.R.S.D College, University of Delhi, Dhaula Kuan, New Delhi-110021, India.
"It is strange that as "more intelligent beings", we try to understand the 'origin of life' but when we merge back into our creator, then we will understand the 'why' of the creation, but we know then, we will not wish to know this any longer"
(Original quotation from the dialogues
of the philosophical poem
"Bhagawad-Gita", 1st-2nd century AD)
If Europa has a liquid water ocean beneath the outer ice crust as a result of interior volcanic heating, then it is possible that hydrothermal vents located on the seafloor may provide the necessary conditions for simple ecosystems to exist. Bacteria's present in the water are known to extract nutrients directly from sulphur via chemosynthesis, making sunlight and oxygen unnecessary. Geochemical models have been proposed to explore the possibility that lithoautotropic could be a source of metabolically useful chemical energy for the production of biomass at putative Europan hydrothermal systems. In the absence of oxygen, anaerobic decomposition takes place in these hydrothermal vents. As a result of putrefactive breakdown of organic material (proteins), some elements are produced, such as hydrogen sulfide, methane, ammonia and mercaptans (any sulphur containing organic compound. Evidence has been provided for the presence of mercaptans on the surface of Europa using reflectance spectra returned by the Galileo near infrared mapping spectrometer (NIMS). Absorption was observed at 3.88 mm, attributed to S-H bond of mercaptans, which could be the result of extant bacterial activity. A major scientific question to be answered about the possible existence of life is: If biological process such as methanogenesis and putrefaction are at work then how do they affect observable or measurable quantities? What would be the best way to detect these organisms? Thus the detection and characterization of any bacterial excreta is an integral part of our search for evidence of life on Europa. Any point on the surface of Europa which exhibits properties typical of contamination by bacterial waste should serve as a window to the underlying ocean. Before embarking upon any ambitious project, it would be helpful if we could test this proposal in the laboratory by mimicking the surface of Europa. This could be done by allowing for bacteria to grow for a prolonged period in an artificial pond and then freezing the water. Subsequently one can measure the various physical and chemical properties on the surface of this pond. This will help to understand what we should expect on the surface of Europa and whether the marcaptan signal observed by NIMS can be attributed to the presence of micoorganisms under the forzen surface of Europa. The dry valley lakes of southern Victoria Land of Antarctica (77°S, 163°E) are perennially ice-covered. Surface ice has endogenic sulphur compounds deposited by processes which could be conjectured to be analogous to the ones we describe here.
ORIGIN AND EVOLUTION OF METABOLIC PATHWAYS
Matteo Brilli and Renato Fani*
Dipartimento di Biologia Animale e Genetica,
Via Romana 17-19, 50125 Firenze, Italy
*tel +39 055 2288244
fax +39 055 2288250
The building up of metabolic pathways
represented a crucial step in molecular and cellular evolution.
In fact, if the Oparin's idea on the origin of life is correct,
we can imagine that the exhaustion of the prebiotic supply of
amino acids, bases, and other compounds must have imposed an important
pressure favouring those primordial heterotrophic cells which
became capable of synthesizing those molecules. Thus, the emergence
of biosynthetic pathways allowed primitive organisms to become
increasingly less-dependent on exogenous sources of organic compounds.
Several different theories have been suggested accounting for the establishment of metabolic routes. These explanations include: i) the retrograde hypothesis (Horowitz, 1945; 1965) according to which the present biosynthetic pathways were organized stepwise and backwards from the final metabolites of the pathways; ii) the possibility that at least some biosynthetic routes evolved forwards (Granick, 1965); iii) the idea that metabolic pathways appeared as a result of the gradual accumulation of mutant enzymes with minimal structural changes (Waley, 1969); and iv) the patchwork theory, according to which metabolic routes are the result of the serial recruitment of relatively small, inefficient enzymes endowed with broad-specificity that could react with a wide range of chemically related substrates (Ycas, 1974; Jensen, 1976).
The origin and evolution of metabolic pathways can be studied by sequence comparisons and by the "directed evolution" experiments. The comparative analysis of different metabolic routes (nitrogen fixation, bacteriochlorophyll and histidine biosynthesis) suggested that: i) in the course of molecular evolution different mechanisms might have concurred in the arisal of new metabolic abilities; ii) gene duplication is a major force in genome evolution and paralogous duplications of DNA stretches may have played an essential role in shaping the main metabolic pathways during the early stages of molecular evolution; iii) duplication may concern gene portions, coding for protein domains and motifs, entire genes, and entire operons.
Case study 1. Nitrogen fixation: a cascade of gene and operon duplication.
Nitrogen fixation is a complex metabolic process involving several genes (nif), but very little is known about its origin and evolution. A detailed analysis of nif gene products revealed that nifDK and nifEN, encoding the a and b subunits of nitrogenase, and the components of the NifEN enzymatic complex, involved in FeMo-Co biosynthesis, belong to a paralogous gene family. This analysis also permitted to trace their possible evolutionary history; according to the proposed model the four genes are the result of two successive duplication events, very likely predating the appearance of the Last Universal Common Ancestor (LUCA). The first paralogous duplication event involved an ancestral gene (encoding a low specificity ezyme able to catalyze several reactions) leading to a bicistronic operon which, in turn, underwent a paralogous operon duplication event originating the ancestors of the present-day nifDK and nifEN operons. A further analysis revealed that these genes exhibited a significant degree of sequence similarity to the bacterial bchB and bhcN genes, which code for two components of protochlorophyllide reductase, and to the products of bchY and bchZ, encoding two components of chlorin reductase. Data obtained strongly suggested that bchB, bchN, bchY, and bchZ belong to the nifDKEN paralogous gene family, that they might have arisen from two successive duplications involving one of the two operons above mentioned, and established an evolutionary link between nitrogen fixation and bacteriochlorophyll biosynthesis.
Case study 2. Histidine biosynthesis: a paradigm for the study of the origin and evolution of metabolic pathways.
The histidine biosynthetic pathway is one of the best characterized anabolic pathway. There are many clues indicating the antiquity of this pathway, suggesting that it might have been completely assembled before the appearance of the last common ancestor and that its origin probably started in the early stages of molecular evolution. The availability of completely sequenced genomes from different (micro)organisms belonging to the three cell domains permitted a deep analysis of his genes, which revealed that paralogous gene elongation and duplication events occurred frequently and that they played a major role in shaping the pathway. Moreover, we found that (at least) seven his genes underwent different gene fusion events in some bacterial and eucaryal lineages, but not in Archaea, suggesting that the ancestral his pathway was constituted by mini-genes which underwent different rearrangements during evolution. Data obtained also suggested that some his genes are the descendants of genes encoding less specific enzymes, supporting the Patchwork hypothesis.
TEN YEARS OF TRIESTE CONFERENCES ON CHEMICAL EVOLUTION AND ORIGIN OF LIFE: A PICTORIAL OVERVIEW
Mohindra S. Chadha
In this presentation, aimed at re-capitulation of ten years of Trieste Conferences, on Chemical Evolution and Origin of Life, an attempt will be made to highlight the Scientific, Educational and Cultural aspects (through pictures taken) at the six Conferences held so far. To have been present at the First Trieste Conference held in October 1992 and now at the Seventh Conference and all the others in between has provided with a perspective which I wish to share.
The first Trieste Conference which was the brain-child of Prof. Abdus Salam and Prof. Cyril Ponnamperuma was held in October 1992 in Trieste under the joint umbrella of International Atomic Energy Agency and the United Nations Educational, Scientific and Cultural Organisation and was attended by both the stalwarts. This inter-disciplinary international conference was entitled Chemical Evolution: Origin of Life and defined the scope and objectives of this novel effort.
The second Trieste Conference (Oct. 1993) was entitled Chemical Evolution: Self-organisation of the Macromolecules of Life and was dedicated to Cyril Ponnamperuma on his 70th birthday. At this conference many of the erstwhile collaborators of Cyril Ponnamperuma participated and the proceedings of the conference were edited by Julian Chela-Flores and Cyril Ponnamperuma's former collaborators namely: Mohindra S. Chadha, Alicia Negron-Mendoza and Tairo Oshima.
The third Trieste Conference (Sept. 1994) was entitled Chemical Evolution: Structures and Model of the First Cell and was designated as the Alexander Ivanovich Oparin 100th Anniversary Conference. This was the best attended conference of the three Trieste conferences till then and the presentations on planetary, extraterrestrial and interstellar conditions broke a lot of new ground.
The fourth Trieste Conference (Sept. 1995) was the first conference of the series which was held after the untimely and sudden demise of Cyril Ponnamperuma, the co-founder of this series of conferences. He was involved in the early part of the preparation of this conference but unfortunately was not to live to witness it's deliberations. Such is Life! The Conference was entitled Chemical Evolution: Physics of the Origin and Evolution. The Conference was aptly dedicated to the memory of Cyril Ponnamperuma. There were general overview presentations by John Oro on Cosmic Evolution and Sidney Fox entitled Experimental Retracement of Terrestrial Origin of An Excitable Cell: Was it Predictable? In a special session, homage was paid to Cyril Ponnamperuma and excerpts of letters received from various academies, institutions and admirers of Cyril Ponnamperuma were read out. A touching note received from his wife (Valli) and daughter (Roshini) was also shared.
The fifth Trieste Conference (Sept. 1997) was entitled Exobiology, Matter, Energy and Information in the Origin and Evolution of Life in the Universe and was dedicated to the memory of Abdus Salam the co-founder of the Trieste series of Conferences and Director of ICTP, who had unfortunately passed away after prolonged illness. This conference had as many as 12 sponsors and was largely attended. The highlights were talks by: Chela-Flores entitled: Abdus Salam - From Fundamental Interactions to the Origin of Life. The Abdus Salam lecture by John Oro entitled: Cosmocological Evolution A Unifying and Creative Process in the Universe. The Cyril Ponnamperuma lecture by Frank Drake, namely The Search for Intelligent Life in the Universe. The opening lecture: The Theory of Common Descent by Richard D. Keynes and a Public Lecture: Are We Alone in the Universe by Paul Davies. This Conference was unique in focussing on Exobiology in general and on Comets, Planets and the Interstellar Medium in particular.
The sixth Trieste Conference (Sept 2000) was entitled First Steps in the Origin of Life in the Universe and was dedicated to Giordano Bruno whose intuitive concepts have relevance to current enquiries related to the First Steps in the Origin of Life in the Universe. This conference had as many as 11 sponsors. The conference featured a special lecture by Stanley Miller who presented the possibility of Peptide Nucleic Acids as A Possible Primordial Genetic Polymer. The Abdus Salam lecture entitled: Physics and Life was delivered by Paul Davies and the Cyril Ponnamperuma lecture by J. William Schopf entitled: Solutions to Darwin's Dilemma: Discovery of the Missing Precambrian Records of Life. All the three presentations were quite scintillating. A new feature of the sixth Trieste Conference was inclusion of a section entitled: Historical Aspects which featured work of Sidney Fox (by Aristotle Pappalis), Theories on Origins of Life between 1860-1900 (by F. Raulin-Carceau) and Reminiscences- Pont-a-Mousson- 1970 to Trieste-2000 (by Mohindra Chadha).
The other main topics of the conference dealt with Life without Starlight and questions asked were: Can Life Originate in the absence of Starlight? In a Pre-Dinner lecture entitled NEW PARADIGMS OF SETI, Frank Drake brought the audience up to date in this challenging and thrilling venture of scientific endeavour. The Sixth Trieste conference had all the embellishments of the previous conferences as envisioned by the two founders (Abdus Salam and Cyril Ponnamperuma).The Keynote addresses given by leading researchers in their respective fields were authoritative. Many young scientists from both the industrialised countries and those from developing countries, coming from different parts of the Globe enriched themselves greatly from their participation in this conference as the earlier ones. In all over 500 participants have benefited from the Trieste Conferences so far.
The last Six Trieste Conferences have brought together scientists (both experimental and theoretical), philosophers and theologians of repute. The intellectual content of the discussions and many debates has been of a high order and the future for these inter-disciplinary international deliberations seems to be very bright. Our thanks are due to Julian Chela-Flores, Tobias Owen and Francois Raulin who have continued to carry the torch lit by Cyril Ponnamperuma and Abdus Salam. The sponsors and the organising committee also deserve an applause. This tribute to the activities of a decade of Trieste Conferences on Chemical Evolution and Origin of Life will be presented through a Pictorial Overview.
FATE OF GLYCENE AND OTHER COMPLEX BIO-MOLECULES DURING INTERSTELLAR COLLAPSE
Sandip K. Chakrabarti
S.N. Bose National Centre for Basic Sciences and Centre for Space Physics
P-61 Southend Garden, Garia,
We present results of time evolution of complex bio-molecules including glycene, amino acid etc. through a chemical evolution of over 430 species in a collapsing interstellar cloud. We include grain and surface chemistry for efficient evolution of lighter elements at each shell of the cloud. We include effects of radiative processes as well. Our conclusion is that glycene should have a sigificant abundance and it should be detectable.
A FUNCTIONAL AND SELF-REFERENTIAL MODEL FOR THE GENETIC CODE
Romeu Cardoso Guimarães1, Carlos Henrique Costa Moreira2
Univ. Federal Minas Gerais, Inst. Ciências Biológicas, Dept. Biologia Geral1, Dept. Matemática2 31270.901 Belo Horizonte MG Brasil. TelFax +55-31-3499.2570; email@example.com
The structure of the genetic code is based on palindromic pairs of anticodons, where the central and 3' bases (principal dinucleotides, pDiN) are complementary to each other but the 3' bases are paired with the wobble bases: 5'-central-3' : 3'-central-5'. The matrix is divided into homogeneous (Ho; RR:YY quadrants) and mixed (Mx; RY:YR quadrants) pDiN sectors. Sectors are composed of axial (Ho, AA:UU, GG:CC; Mx, AU:UA, GC:CG) and non-axial (Ho, GA:CU, AG:UC; Mx, AC:UG, GU:CA) pDiN boxes. The degeneracy distribution follows (1) in the axial boxes, the pDiN base composition and thermodynamic stability: core boxes are simple (GG Pro:CC Gly, GC Ala:CG Arg), the tips complex (AA Phe, Leu:UU Asn, Lys; AU Ile, Met:UA Tyr, X) and (2) the central base type, with purine precedence, in non-axial boxes: central R simple (GA Ser, AG Leu, AC Val, GU Thr), central Y complex (in the pair order: CU Ser, Arg; UC Asp, Glu; UG His, Gln; CA Cys, Trp, X). Complex boxes also obey the purine precedence rule. 5' R anticodons were maintained by first occupants and 5' Y conceded to new occupants: YAA and YCU to the hexacodonic expansions of Leu and Arg; YAU to Met and fMet, YUA to X, and YCA to Trp and X; in the other central U boxes, YUG to Gln, YUC to Glu and YUU to Lys.
Our model for generation of the code indicates: it was preceded by the peptidyl-transferase activity; attributions were gradually added; tRNA dimers (palindromic pairs) were formed and directed the order of entry of attributions. In an early stage, the mRNA function was accomplished either by one member of a pair of tRNAs, entering the ribosome as tRNA dimers, or by a ribosomal correlate of codons or anticodons, in which case tRNA dimers would not enter the ribosome. In the absence of mRNA, protein synthesis was not a process of translation and was self-referential (referring only to the existing components of the system); there were also no problems with non-sense or ambiguous codons. After the entrance of mRNA, protein synthesis became translational and referring to the larger system which produced the mRNA.
Among the first functions of peptides produced were those of belonging to the protein synthesis system, being intrinsically stable and RNA binders, so that RNA became stabilized as ribonucleoprotein. Evolution of protein conformations was from coils and turns to helices then strands. Stage 1. First attributions were of the hydropathy correlation outliers, (GlyCC:GGGly, the latter displaced afterwards by Pro, and SerGA:CU); these are now catalyzed by synthetases class 2 (aRS2) but could have started ribozymic; all other attributions obey the hydropathy correlation. Stage 2 completed the Ho sector: AspUC was followed by the aRS1 pair GluUC:AGLeu; AsnUU, derived from Asp, was followed by the unique LysUU:AAPhe pair of bulky amino acids (Lys may be class 2 or 1, PheRS2 acylates at 2', as done by all aRS1). Stage 3 took AlaGC:CGArg and the aRS1 pair ValAC:UGGln, after HisYUG concession to Gln. Stage 4 took ThrGU:ACCys, Trp, then the aRS1 pair Ile, MetAU:UATyr. Of the 8 pDiN pairs, 2 are aRS class discordant: Ala/Arg and Thr/Cys, Trp.
Punctuation was achieved non-specifically in Stage 2, at the Ho axis, through polar organization of protein sequences, concentrating protein N-end-stabilizing (Gly, Pro) and -destabilizing (Lys, Phe) amino acids at the N-ends and C-ends, respectively. Specific punctuation (last step of Stage 4; tips of the Mx axis plus the CA box) was derived from the functional pDiN slippage of fMet to CAU and of the initiation codon to AUG, which led to interference of the CA (Cys, Trp box) and UA (Tyr box) with the pairing of fMet to the initiation codon. Therefore, X tRNAs were deleted.
Support: CNPq, FAPEMIG.
Guimarães 2001 In: First steps in the origin of life in the universe. Ed. J Chela-Flores, T Owen, F Raulin; Kluwer, Dordrecht, 91-4; Guimarães, Moreira 2002 In: Fundamentals of life. Ed. G Pályi, C Zucchi, L Caglioti; Elsevier, Paris, 249-76; Abstrs. 13th Internat. Conf. Orig. Life, Oaxaca MX 2002
PHOSPHATE IMMOBILIZATION BY OXIDE PRECURSORS AND PYRITE: IMPLICATIONS ON PHOSPHATE AVAILABILITY BEFORE LIFE ON EARTH
Fernando de Souza-Barros c, Ana C. Tessis d, Marisa B. M. Monte a, Ana C. P. Duarte a, José A. P. Bonapace b , Manoel R. do Amaral Jr. c,*, Raphael Braz Levigard d, Yonder A. Ching-San Jr. d, and Adalberto Vieyra d .
a Centro de Tecnologia Mineral (CETEM), Ministério da Ciência e da Tecnologia;
b Instituto de Química, Universidade Federal do Rio de Janeiro;
c Instituto de Física, Universidade Federal do Rio de Janeiro;
d Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro.
We present recent studies1, 2 based on the proposal that if the aqueous phosphorous-capture mechanism by iron oxide precursors was inhibited in prebiotic anoxic scenarios then soluble phosphates could have been more available than what is observed now. In this communication we examine trapping mechanisms of orthophosphate (Pi) and pyrophosphate (PPi) by Fe/S minerals. The attachment of (Pi) onto aggregates of iron-3 oxyhydroxide is compared with the one reported for the product of its condensation, PPi. The electrophoretic profiles of the Pi- and PPi-aggregate complexes reveal different pH-modulated interactions of the phosphorylated compounds with both the aggregate and its aqueous surrounding layers. On the other hand, pyrite sorption properties revealed that acidic media favoured Pi sorption whereas desorption is facilitated if mild alkaline conditions are present. In addition it has been observed that pyrite surface charges are sensitive to pH, Mg and SO4, thus affecting the Pi sorption properties. All together, these results support the hypothesis that the availability of Pi and PPi in prebiotic eras would have been modulated by prevailing trapping mechanisms in anoxic environments, by local variations of Mg and SO4 and by acidic¦mild-alkaline transitions.
1."Phosphate immobilization by oxide precursors: Implications on phosphate availability before life on Earth", Monte et al., Orig. Life Evol. Biosphere, in the press, 2003
2."Pyrite sorption and desorption of inorganic phosphates in primitive aqueous scenarios" Levigard et al., in preparation
# Author for correspondence, e-mail:
firstname.lastname@example.org; FAX: +55-21-2562-7368
Financial support: CNPq, FUJB-UFRJ, Finep (Brazil)
A MECHANISM FOR THE PREBIOTIC
EMERGENCE OF PROTEINS:
THE ROLE OF PROTON GRADIENTS AND HIGH TEMPERATURE IN THE POLYMERIZATION OF
AMINO ACIDS EMBEDDED IN BILAYERS
P. De Vladar, Harold, 1*, Cipriani, Roberto,2**, Scharifker, Benjamin 3***,
and Bubis, Jose 4****
1 Centro de Biotecnologia, Fundacion IDEA, Caracas, Venezuela,
2 Laboratorio de Evolucion Morfologica, Departamento de Estudios Ambientales,
3 Laboratorio de Electmquimica, Departamento de Quimica,
4 Laborario de Quimica de Proteinas, Departamento de Biologia Celular,
Universidad Simon Bolivar, Caracas, Venezuela.
One of the most intriguing problems in the study of the origin of life is how complex macromolecules, and the processes in which they are involved, arise from simple molecules commonly available in prebiotic environments. The resulting prebiotic processes, either compartmentalized by amphiphilic molecules arranged in bilayers or spread across physical interfaces, become potential targets for selective mechanisms. The origin of complex macromolecules depends upon a variety of conditions abundantly described in models of prebiotic scenarios or worlds, such as those in which RNA and
thioesters dominate the fundamental processes of catalysis and polymerization. Autocatalysis and transmission of genetic information are the simultaneous functions of the ribonucleic acid precursor in the RNA world. On the other hand, spontaneous protein synthesis resulting from the polymerization of thioesters is the main process in a world dominated by these molecules. In any of these worlds, acidic, low-oxygen environments and extreme temperatures could have increased the velocity of chemical reactions and the stability of their products. In this study we propose that peptide formation might have occurred by the polymerization of amino acids embedded in amphiphilic bilayers. This polymerization could have been driven by a flux of protons through the bilayer and under conditions of high temperature. Our conceptual model involves a bilayered membrane separating two environments with different pH values at high temperatures. Given that under certain conditions, (a) differences in proton concentrations are capable to produce enough free energy to couple chemical reactions, and (b) the formation of peptide bonds will release OH ions, then a continuous influx of protons can be coupled with the formation of the peptide bond. Protons could bind to the hydroxile ions producing water and continuously displacing the reaction from equilibrium. We developed a mathematical model, using phenomenological equations and computer simulations, in which the proton flux is proportional to the polymerization of amino acids. From the results of these simulations, we estimated the size distribution of the oligopeptides and designed two possible experimental setups to test our theoretical results. One of these experiments is currently underway. The mechanism that we propose is a novel process that describes the early origin of proteins as macromolecules embedded in the bilayer, and links the origin of membrane proteins to the emergence of their functionality.
* E-mail: email@example.com
** E-mail: firstname.lastname@example.org
*** E-mail: email@example.com
**** E-mail: firstname.lastname@example.org
A SURFACE-MEDIATED ORIGIN OF THE RNA WORLD: "BIOLOGICAL" ACTIVITIES OF CLAY-ADSORBED RNA MOLECULES
Marco Franchi, Elisa Biondi, and Enzo Gallori
Department of Animal Biology and Genetics, University of Florence - Florence (Italy)
Studies carried out in different fields in the last twenty years have indicated that RNA could have played a pivotal role in the origin of life on Earth. In fact, the RNA molecule can act both as an information repository and as a catalyst necessary for cellular reactions ("ribozyme"). Moreover, its building blocks are distributed in many important metabolic pathways. These observations led to the concept of an "RNA World" during the firsts stages of the appearance of life.
If the RNA World ever existed, however, it seems improbable that it developed in "free" aqueous solution, due to the difficulty of polymerization reactions and the instability of polymers in an aqueous environment. In recent years, numerous observations have suggested the hypothesis of a surface-mediated origin of the RNA World. For example, clay minerals can favour the formation of considerably long oligonucleotides (Ferris et al., 1996) and can increase the environmental persistence of adsorbed nucleic acids (Gallori et al., 1998; Franchi et al., 1999).
At present, it is crucial to understand if and how RNA-like molecules adsorbed on clays, in the prebiotic environment, were in the right conditions to undergo chemical evolution leading to primitive biological self-replicating systems. In other words, to evolve these polymers must have been able to store genetic information, to specifically interact with other biopolymers, and to catalyse "biologically relevant" reactions.
In this communication, we present preliminary results of our studies on the biological activity of RNA molecules adsorbed on clay minerals, particularly with regard to: i) their enzymatic replication by RT-PCR (storage and transmission of genetic information); ii) their specific interaction with complementary RNA strands (interaction with other biopolymers); and iii) the catalytic activity of adsorbed oligonucleotides like "hammerhead" ribozymes (specific catalysis).
Franchi et al., 1999, Orig Life Evol Biosph 29: 297-315;
Ferris et al., 1996, Nature 381: 59-61;
Gallori et al., 1998, Symbiosis 25: 311-322.
SOME ENGINEERING CONSIDERATIONS ON THE CONTROVERSIAL ISSUE OF HUMANOIDS
Department of Mechanics, Politecnico di Torino,
C. Duca degli Abruzzi 24, 10129, Torino, Italy
email@example.com / fax: ++39 011 564 6999
Many papers have been published in the past on the issue of the possible existence of humanoid extraterrestrial intelligence (ETI). The issue is very old: the first to take a firm stance on the subject was Galileo Galilei, who in his Istoria e dimostrazioni intorno alle macchie solari e loro accidenti (history and demonstrations on the sunspots and their details) (1613) states that he considered as a false and condemnable point of view to assume the existence of inhabitants on Jupiter, Venus, Saturn and the Moon, intending for 'inhabitants' animals like ours, and particularly men. But then he states that it is possible to believe that living beings and plants exist on the Moon and the planets, whose characteristics are not only different from those of the beings on the Earth, but also from what our wildest imagination can produce.
The prevalent opinion is now that the humanoid form is rather an exception than a rule.
The aim of the present paper is to consider an intelligent being as a sort of machine which has to perform a number of tasks, and to discuss whether the humanoid form and humanoid intelligence (intended as an intelligence accompanied by consciousness similar to those of humans) is dictated by them. While not intending to supply answers but only to formulate some problems, it is suggested that, although there is no doubt that a close relationship between our layout and our essence of intelligent beings exists, this is not enough to support any claim that the humanoid form is prevalent or even that it may exist outside our planet.
STUDIES ON COPPER CHROMICYANIDE AS PREBIOTIC CATALYST
Kamaluddin and Shah Raj Ali
Department of Chemistry
Indian Institute of technology Roorkee, Roorkee 247 667, India
Processes in chemical evolution must have involved several catalysts multifunctional in nature. We proposed that metalcyanogen complexes of general formula M2[M(II) (CN)6] formed in the primeval seas might have catalysed a class of reactions essential for the origin and evolution of life. Based upon this hypothesis we have synthesized a series of metal cyanogen complexes and have shown them to have strong affinity towards several organic molecules of evolutionary importance.
Recently, we found that copper-chromicyanide, Cu3[Cr(CN)6]2. 14H2O possesses high adsorption capacity for ribose nucleotides and able to catalyze formation of disulfide bond through dimerisation of cysteine. Cu-chromicyanide was also found to facilitate conversion of fructose to pyruvaldehyde.
The present study suggests that the metal chromicyanides might have stabilized the organic molecules of prebiotic relevance and have catalysed a class of reactions essential for evolution of life.
COENZYMES IN EVOLUTION OF THE RNA WORLD
Mikhail S. Kritsky
A. N. Bach Institute of Biochemistry, Russian Academy of Sciences,
Leninsky Prospekt 33, Moscow 119071, Russia,
According to the RNA-world hypothesis, the early life was based on polyribonucleotides. That is, RNAs, which could have served as their own genes also performed catalytic functions in the absence of genetically ordered proteins. The analysis of both natural and selected ribozymes indicates that certain types of catalytic activities, e.g. oxidoreductases, are absent in polyribonucleotides. A possible way the RNA world could compensate for their absence to maintain a primitive metabolism was the attachment of nucleotide-like coenzymes to polynucleotides. Molecules such as flavin, pterin and nicotinamide coenzymes are structurally similar to canonic ribonucleotides and their ability to attach nucleic molecules both covalently and by non-covalent high-affinity binding have been experimentally demonstrated. Due to high activity of excited flavin, pterin and nicotinamide coenzymes in energy and electron transfer processes such attachment could have a dualistic significance for evolution. Since light dramatically elevates reactivity of these compounds, especially as redox catalysts, it is suggested that the presence in proto-RNAs of nucleotide-like coenzymes capable to perform photocatalytic functions could expand the repertoire of catalytic activities in the RNA world. On the other hand, the coenzyme attachment to polynucleotide had to increase risk of its coenzyme-sensitized degradation.
The support by Russian Foundation
for Basic Research Grant 01-04-48268_ is appreciated
FACTORS AFFECTING THE GROWTH OF CHEMOLITHOAUTOTROPHS AND COMPLEX PHOTOAUTOTROPHS IN THE TROPICAL ANDEAN HIGH MOUNTAIN AND ITS EXOBIOLOGIAL IMPLICATIONS
Vicente Marcano 1, Paula Matheus 1, Alirio Balza1, Nelly Garcia 1, Rafael Navarro-Gonzalez 2, Christopher McKay 3, Wanda Davis 4 and Ernesto Palacios-Prü 1
1 Laboratorio de Biología y Química Evolutiva, Centro de Microscopía Electrónica,
Universidad de Los Andes, P. O. Box 163, Mérida, Venezuela.
2 Laboratorio de Química de Plasma y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, México D.F, México.
3 Space Science Division, NASA Ames Research Center, Moffet Field, CA 94035 USA
4 SETI Institute- Space Science Division, NASA Ames Research Center, Moffet Field, CA 94035 USA
Surface and subsurface biota in the Andean high mountain are near the limits of photoautotrophic and chemolithotrophic life in the tropical region. Therefore, the relationship between N2, O2, and CO2 partial pressures, nitrogen fixation at soils, chlorophyll content, biological productivity (P/Pmax), and surface and subsurface thermal variation at the Andean high mountain was evaluated during the rainy and dry periods (2002 year) in order to determine the main factors affecting the growth of organisms living at that region. Climatic data including relative humidity and precipitation were obtained from 9 meteorological stations placed between 2448 and 4800 m at the Sierra Nevada de Mérida, Venezuela. These data were related to the metabolic activity (viz. ammonification, nitrification and CO2 assimilation) investigated in several plant species and soil microorganisms.
The obtained results suggest that the poor development of the plants correlated to the altitude could be a direct consequence of the low O2 and CO2 levels recorded in the higher altitudes, which reduce the photosynthetic activity, biological productivity, and the production of NO3- at the soils. Hence, chlorophyll content was inversely correlated to the increment of the altitude (2.3 x 10-2 mg Chl (a+b) g-1 dry weight m-1). Even chemolithotrophic bacteria cannot carry out the fixation process by nitrification at the snow zone (> 4700 m) because this process require aerobic conditions while the high concentrations of NH3 found in the snow zone correspond to the anaerobic nature of bacterial ammonification. Environments with a PO2 < 125 mbar showed a very low frequency and diversity of complex photosynthesis-based life forms due to the aerobic feature of bacterial nitrification. Altitudinal distribution of mean NO3- values revealed the existence of a "critical nitrogen-fixing zone" localized at timberline (~ 3250 m). Wider daily surface thermal oscillations (up to 52°C) were recorded between 3700 and 4270 m having 20 x 10-2 and 18 x 10-2 mbar of CO2 whereas lower or higher places showed reduced daily oscillations. Minimum PCO2 suitable for the occurrence of C3-advanced photosynthesis-based life forms in these environments had have values > 17 x 10-2 mbar corresponding to a mean temperature > 277 K and to a biological productivity rate P/Pmax ~ 0.27 whereas that minimum PCO2 suitable for the occurrence of C4-advanced photosynthesis-based life forms in those environments not exceeded values ~ 14 x 10-2 mbar. Further, a "critical photosynthetic boundary" also localized at timberline was defined having a mean surface temperature of ~ 11°C, P/Pmax ~ 0.64, and a PCO2 of ~ 21 x 10-2 mbar. On the other hand, reactions between N2 and H2O in the atmosphere surrounding lightning discharges can provide an important source of NOx even at altitudinal ranges where O2 is a minor atmospheric constituent (viz. snow zone), and therefore could allow the availability of fixed nitrogen for complex photosynthesis-based organisms living in the tropical Andean high mountain.
SPACE WEATHER AND SPACE CLIMATE:
LIFE INHIBITORS OR CATALYSTS?
INAF-Osservatorio Astronomico di Trieste,
Loc. Basovizza n. 302, 34012 Trieste, Italy
and Dept. of Physics, Trieste University.
In the present evolutionary stage the Sun as a star exhibits an almost stable radiation output, which is expected to endure on a long time scale and characterizes the Space Climate (SpC). On a short tine scale the solar activity perturbs instead the heliosphere by originating radiation outbursts, highly energetic particle emissions and magnetized plasma clouds, which characterize the Space Weather (SpW). A similar phenomenology can be typical in solar-like active stars, where it can be even more pronounced according to the star type, and strongly affects the planetary environments. In this work we speculate on the possible mutual role of SpW and SpC on life birth and evolution in a planetary environment, stressing the inadequacy of the basic concept of Habitability Zone and the relevance of SpW and SpC to life-genicity and life-sustainability.
SEARCHING FOR DYSON SPHERES IN THE MILKY WAY
Departamento de Astronomia
Casilla 306, Santiago
Phone +56 2 686 4946
Fax +56 2 686 4948
A new search for Dyson spheres in the Milky Way is being carried out. This is based on massive datasets that cover different wavelengths, including optical (BVRI), near-IR (JHK), and mid-IR bands. The first results will be presented and discussed. The results are compared with similar surveys that have been made so far.
MARS-LIKE SOILS ON EARTH IN THE ATACAMA DESERT,
Rafael Navarro-González1,2, Fred A. Rainey3, Paola Molina1, Danielle R. Bagaley3, Becky J. Hollen3, José de la Rosa1, Alanna M. Small3, Richard C. Quinn4, Frank J. Grunthaner5, Luis Cáceres6, Benito Gomez-Silva7, Arnaud Buch2, Robert Sternberg2, Patrice Coll2, Francois Raulin2, and Christopher P. McKay8,
1 Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Apartado Postal 70-543, México D.F. 04510, México.
2 Laboratoire Inter-Universitaire des Systèmes Atmosphériques, UMR CNRS 7583, Universités Paris 12 & Paris 7, CMC, 61 Avenue du Général de Gaulle F 94010 Créteil Cedex, France.
3 Department of Biological Sciences, 202 Life Sciences Building, Louisiana State University, Baton Rouge, LA 70803, USA.
4 SETI Institute, NASA Ames Research Center, Moffett Field, CA 94035-1000, USA.
5 Jet Propulsion Laboratory, Pasadena CA, 91109, USA.
6 Instituto del Desierto y Departamento de Ingeniería Química, Facultad de Ingeniería, Universidad de Antofagasta, PO BOX 170, Antofagasta, Chile.
7 Instituto del Desierto y Unidad de Bioquímica, Departamento Biomédico, Facultad Ciencias de la Salud, Universidad de Antofagasta, PO BOX 170, Antofagasta, Chile.
8 Space Science Division, NASA-Ames Research Center, Moffett Field, CA 94035-1000, USA
The Viking Missions to Mars showed the Martian soil to be lifeless and depleted in organic material, and indicated the presence of one or more reactive oxidants. Here we report the presence of Mars-like soils in the extreme arid region of the Atacama Desert. Chemical and microbiological studies indicate the presence of organics at trace levels composed primarily of highly oxidized organic refractory material, extremely low levels of culturable bacteria and no recoverable DNA in the soil. We have simulated the Viking Labeled Release experiment in Atacama using formate and separate biological and non-biological isomers of alanine and glucose, and found that there is active decomposition of organics and it is entirely non-biological.
THE IMPORTANCE OF BIASED SYNTHESIS IN CHEMICAL EVOLUTION STUDIES.
A. Negron-Mendoza1, S. Ramos-Bernal1, and G Mosqueira2
1Instituto de Ciencias Nucleares, UNAM, A.P. 70-453, Mexico, D.F 04510
2Dirección General de Divulgación de la Ciencia, UNAM. Cd. Universitaria, A.P. 70-487, 04510
México D.F., México.
For the appearance of life, a physical and chemical preamble was needed. Today, there is a large variety of experimental data to support the hypothesis for the abiotic formation of organic compounds. Although much knowledge has been gain, still many questions remain.
One important factor in chemical evolution is biased synthesis. These led selectivity in the formation of organic compounds in order to reach the complex system that we call life.
In this paper, we propose a simple chemical system, decarboxylation of fatty acids, or deamination of amino acids that follow a preferential pathway over others possibilities in which both solid surfaces and radiation play an important role.
Fatty acids undergo a complex decomposition in the presence of radiation. Thus, radiation-induced reactions produce dimers and oligomeric products. Fatty acids present a very slow decarboxylation in the presence of montmorillonite alone. The reaction is accelerated at higher temperatures, but it is enhanced in many folds in the presence of ionizing radiation. Drastically, the normal way of radiation -decomposition reactions changes if the system contains a clay mineral.
ENANTIOSELECTION CAUGHT ON THE ACT: CHIRAL CONFORMERS FROM ACHIRAL COMPLEXES
Gyula Pályi,a Claudia Zucchi,a Roland Boese,b Lajos Bencze,c Luciano Caglioti,d
a Department of Chemistry, University of Modena and Reggio Emilia, Via Campi 183; I-41100 Modena, Italy; firstname.lastname@example.org
b Institute of Inorganic Chemistry, University of Essen, Universitätsstrasse 5-7, D-45117 Essen, Germany
c Müller Laboratory, Department of Organic Chemistry, University of Veszprém, Egyetem-u.6, H-8200 Veszprém, Hungary
d Department of Chemistry and Technology of Biologically Active Compounds, University "La Sapienza" Roma, P.zale Moro 5, I-00185 Roma, Italy
Prebiological or early biological enantioselection, leading to so-called biological homochirality is one of the most exciting challenges of molecular sciences . The various theories about this problem are characterized by intellectual excellence , but the experimental verification is still in initial stage .
Our approach takes in consideration the recently recognized role of transition metal ions in the origins of life . We report here on the development of chiral conformations by the long-range interaction of achiral ligands coordinated to cobalt (I) ions. Systematic structural changes and MO calculations identified concerted intramolecular movements, which lead to partial or even quantitative symmetry splitting in these complexes. This self-organization occurs both by ligand-ligand and ligand-metal-ligand interactions.
 Reviews: (a) Keszthelyi, L.,
Quart. Rev. Biophys., 1995, 28, 473-507.
(b) Pályi, G., Zucchi, C., Caglioti, L. Advances in
Biochirality (Pályi, G., Zucchi, C., Caglioti, L.,
Eds.), Elsevier, Amsterdam, 1999, pp. 3-12.
 Most recent results: Keszthelyi, L., Fundamentals of Life (Pályi, G., Zucchi, C., Caglioti, L., Eds.), Elsevier, Paris, 2002, pp. 99-103.
 E.g., (a) Szabó-Nagy, A., Keszthelyi, L., Proc. Natl. Acad. USA, 1999, 96, 4252-4255. (b) Singleton, D.A., Vo, K.L., J. Am. Chem. Soc., 2002, 124, 10010-10011.
 e.g., Huber, C., Wächtershäuser, G., Science, 1997, 276, 245-247; 1998, 281, 670-672.
MINIMAL UNIT OF TERRAFORMING
AN ALTERNATIVE FOR REMODELLING MARS
Héctor Omar Pensado Díaz
Instituto de Ciencias Avanzadas, A. C.
Several decades ago certain models for terraforming Mars for its optimal condition for life had been proposed. These stated models outline the alternative of raising the global temperature of the red planet by emiting green house type gases and cold weather adapted plants (Sagan1973; Averner and MacElroy 1976; McKay 1982) as well as super green house gases as a first stage on the terraforming process (Lovelock and Allaby 1984; Marinova 2000; Gestell 2001) and the usage of chemical factories and orbital mirrors (Zubrin and McKay 1997) with the same purpose. These approaches would densify the atmosphere by reactivating the hydrological cycle followed by the next stage on the terraforming process, the introduction of photosynthetic microorganisms.
The current tendency for Mars terraforming is the global warming of the planet. However, this document suggest a model for terraforming Mars in sections with a tool called the Minimal Unit of Terraforming (MUT) which comprises dome shaped structures built from translucid plastic trends stuck on the ground, so they could generate an inner greenhouse effect by raising the pressure. By this, it would have an inner environment which would interact with the surroundings helped by the gas exchange and biological ground prosecution. Then, the MUT collaborate as well on the ground gas reduction process creating a difference in the temperature and releasing the gases out of the atmosphere. Mars terraforming would begin with the processes listed above, considering that the MUT would serve Mars just as cells serve the photosynthetic organisms. And so, the atmosphere reconvertion and the ground microterraforming would start, but with consequences for the planet.
Gaia principles by J. Lovelock and L. Margulis had been considered for the establishment of an environment inside the MUT since life means plasticity and it can be adapted and adapt the surroundings by bringing climate and biological balance. This is important since life sown inside the MUT would not have an environment like that of the Earth and Mars, but a neutral environment which would be in thermodynamic lack of equilibrium with the Martian surface, just like a cell is protected by its membrane from the outside world. In that case, the membrane would be the dome shaped structure which would partially isolate the environment from the surroundings letting the gas exchange from the inside to the outside and vice versa by auto regulated valves, which would respond to the amount of millibars in the inside. Inner life would respond then to the dome weather conditions helped by life plasticity and would begin to adapt the inside according to its needs. Then, these structures would be all over the Martian surface and would begin the oxygenation, gas release and biological processes. Once in activity, they would be independent to the Martian atmosphere´s moisture for optimal water and electric power production via the source of solar energy. An acclimatization process of extreme weather condition and drought resistant organisms would have to be held before the installation of the MUT.
The MUT are factories that would create a thermodynamic lack of equilibrium in the surroundings by the generation of and energy wealthy environment in which life would be developed properly. And then, that new life would affect the Martian and its genotypes, creating a feedback system.
The MUT would be independent and could be installed all over Mars. They would take advantage of the natural resources in situ to use them in order to reactivate the different biochemical mechanisms for life. Moreover, the MUT would gradually terraform Mars by building an oasis and oasis areas apparently isolated, but in fact affecting the atmosphere and ground directly. They would transform the atmosphere and the surface. A species spread process affected by the Genotype + Environment interaction would transform the Martian environment, leading to the remodeling of the whole planet. Future crew expeditions could install the MUT with light weight materials from Earth. Then, the in situ natural resources would be taken for the MUT generation, then portable factories would use the silicon and iron form he surface sand to build the MUT in Mars.
ON THE APPARENTLY CONSISTENT L-BIASED ENANTIOMERIC EXCESSES IN METEORITIC EXTRACTS AS REPRESENTING A FORM OF ATTENUATED FORENSIC STEREOCHEMICAL EVIDENCE OF CHIRAL INFORMATION DERIVED FROM TERRESTRIAL CONTAMINATION.
Simon Nicholas Platts (1, 2)
(1.)Geophysical Laboratory (GL),
Carnegie Institution of Washington (CIW/NAI),
5251 Broad Branch Road, NW,
Washington DC 20015-1305 USA
(2.)Dept. of Chemistry,
Rensselaer Polytechnic Institute (RPI/NSCORT),
110 Eighth Street,
Troy NY 12180-3590 USA
We are investigating one possible and seemingly plausible chemical explanation for the significant and very curious L-enantiomeric excesses being reported (Pizzarello et al., ASU/NAI) for the amino acid complements extracted/derived from (especially) Murchison material. Given that reported analyses among the chiral small-molecule inventories of carbonaceous chondritic materials are necessarily limited by both sample size/availability and by these precious samples' curatorial/custodial histories, and given that terrestrially-derived contaminants (many of which in fact contain asymmetric centers) have recently been shown (Watson et al.) to have entered into the free/extractable organic component of Orgueil material, it would seem chemically reasonable now to suppose that imported terrestrial and chirally-biased molecular information will necessarily have 'impressed' itself during the effective 'titration' of available prochiral functionalities contained, perhaps, in native meteoritic macromolecular material; and that such a situation will obtain both during various wet extractive protocols in the lab, and over the longer-term (storage time) during in situ mineral-surface-mediated organic reactions (e.g. slow hydrolyses, ammonolyses, reductions, etc.). In our experimental attempt to at least qualitatively illustrate the essential feasibility of such an explanation in terms of known physical organic chemistry, stereochemistry, and the various methods of achieving variable degrees of stereo- and enantio-controls during organic syntheses, we are attempting to show that the 'titration' of prochiral functionalities (e.g. alkenyl & amidine-type functions) in a 13C-labelled 'HCN-polymer' material (prepared at PSU/NAI, and modeling here for general hydrolysable meteoritic macromolecular material, GHMMM) can be informationally/chirally-biased during typical chemical derivatisations (especially hydrolyses) made in the deliberate presence of an unreactive chiral auxiliary and solvating species, which is commercially-available in both (essentially pure) enantiomeric forms, and which stands as proxy for general terrestrial chiral contamination. While oligomeric HCN compounds, (HCN)x, are certainly too N-rich to stand as realistic model materials for GHMMM, this is actually of secondary concern in the present investigations, as is specific knowledge of the exact nature of the prochiral functions contained.
Pizzarello, S., Zolensky, M. and Turk, K.A. (2003) Nonracemic isovaline in the Murchison meteorite: Chiral distribution and mineral association. Geochimica et Cosmochimica Acta, 67, pp. 1589-1595.
Watson, J.S., Pearson, V.K., Gilmour, I. and Sephton, M.A. (2003) Contamination by sesquiterpenoid derivatives in the Orgueil carbonaceous chondrite. Organic Geochemistry, 34, pp. 37-47.
THERMOCHEMISTRY OF THE DARK AGE
Observatory of Geneva
Chemin des Maillettes, 51
1290 Sauverny (Switzerland)
The dark age of the Universe is generally pointed out as the period between the hydrogen recombination epoch and the horizon of current astrophysical observations. The arrow of time in the cosmic history describes the progression from simplicity to complexity, because the present Universe is clumpy and complicated unlike the homogeneous early Universe. Thus it is crucial to know the nature of the constituents, in order to understand the conditions of the formation of the first bound objects. I will analyse the chemical history of this dark age through the creation of the primordial nuclei to the formation of the first atoms and molecules. Then I will describe the consequences of the molecular formation on the birth of the first stars. In this context I will show that contamination of heavier elements early appeared in the history of the Universe.
CHEMICAL CHARACTERIZATION OF AEROSOLS IN SIMULATED PLANETARY ATMOSPHERES. TITAN'S AEROSOL ANALOGUES
Sandra I. Ramírez 1, Rafael Navarro-González 2, Patrice Coll 3 and François Raulin 3
1Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos. MEXICO
2Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, UNAM, MEXICO
3Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR 7583 Université Paris XII, FRANCE
Titan's surface is hidden , in visible light, by two aerosol layers. The composition of the haze has been studied through ground-based and spacecraft observations, by modeling, and by different experimental approaches.
Tentative analogues of Titan's aerosols have been synthesized in laboratory experiments in order to determine their physical and chemical properties. Photochemistry of atmospheric methane and its decomposition products (ethene and ethyne) is likely at the origin of the production of aerosols (Scattergood et al., 1992). However, a careful determination of the optical properties of the produced polymers in the laboratory shows that they do not match very well with the stratospheric Titan's aerosols. It was found that the solid product that reproduces the satellite's optical properties at best, specifically the geometric albedo, was produced by electrical discharges (Khare et al., 1984; McKay and Toon, 1992; Ramírez et al., 2002). Very little work has been published so far about the chemical properties of these apparently good analogues for the Titan's atmospheric aerosols. Hence there is a need for systematic studies of the solid products synthesized during electrical discharge simulation experiments in order to better understand the chemical properties of the aerosol constituents. This need is particularly important, in the perspective of the exploration of Titan by the Cassini-Huygens (NASA-ESA) mission, which is expected to provide a tremendous amount of new observational data of Titan's environments, starting in 2004. An efficient retrieving of these data requires the availability of many laboratory data, concerning specifically Titan's aerosol analogues.
The description of the initial steps of a systematic study focused in the characterization, by analytical techniques, of laboratory aerosol analogues synthesized from 1hour laser irradiation of a Titan's canonical atmosphere will be presented. How close the solids obtained experimentally represent Titan's aerosols (tholins) is still in debate, but understanding the chemical process which makes tholins and approaching to their chemical constitution can certainly help to easily interpret their role in Titan's atmosphere.
Coll P., Coscia D., Smith N., Gazeau M.-C., Ramírez S. I., Cernogora G., Israël G. and Raulin F. (1999) Experimental laboratory simulation of Titan's atmosphere (aerosols and gas phase). Planet. Space Sci. 47(10-11), 1331-1340.
Khare B. N., Sagan C., Thompson W. R., Arakawa E. T., Suits F., Callcott T. A., Williams M. W., Shrader S., Ogino H., Willingham T. O. and Nagy B. (1984) The Organic Aerosols of Titan. Adv. Space Res. 4(12), 59-68.
McKay C. P. and Toon O. B. (1992) Titan's organic haze. In Proceedings, Symposium on Titan, pp. 185-190. ESA SP-338.
Ramírez S. I., Coll P., Da Silva A., Navarro-González R., Lafait J. and Raulin F. (2001a) Complex refractive index of Titan's aerosols analogues in the 200-900 nm domain. Icarus 156, 515-529.
Raulin F., Coscia D., Ramírez-Jiménez S., Navarro-González R. and Coll P. (1999) Exobiological Importance of Tholins. In The dark matter in the Solar System, Meudon, France.
Scattergood, T.W., Lau E. Y. and Stone B. M. (1992) Titan's aerosols I. Laboratory investigations of shapes, size distributions, and aggregation of particles produced by UV photolysis of model Titan atmospheres. Icarus 99, 98-112.
KINETIC MODELING OF THE SOAI-TYPE ALKYLZINC ADDITION AS A MODEL SYSTEM FOR EFFICIENT CHIRAL AUTOAMPLIFICATION
Jesús Rivera Islas a, Jean-Claude Micheau b and Thomas Buhse a
a Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos,
Av. Universidad Nº 1001, Col. Chamilpa, 62210 Cuernavaca, Morelos, México. b Laboratoire des IMRCP, UMR au CNRS Nº 5623, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse Cedex, France
Experimentally observed chiral autoamplification in specific chemical systems has attracted close scientific interest as a possible explanation for the origin of biomolecular homochirality . Among these few systems, the addition of di-iso-propylzinc (Zn) to a pyrimidine carbaldehyde (CHO) yielding a chiral pyrimidyl alkoxide (COZn) is one of the most prominent examples for autocatalytically driven enantioselective amplification that involves the formation of a chiral carbon . The reaction can be regarded as a prototype system for the dynamics of chiral amplification that is believed to have played a key role in the prebiotic evolutionary pathway from very small enantiomeric imbalances to the virtually homochiral state of the biomolecules. Based on a simplified kinetic model  (Fig. 1), the dynamics of this system have been analyzed and the possible mechanism of chiral autoamplification is discussed. The kinetic model outlines the dynamics of the reaction system similar to a recently analyzed template-directed self-replicating system . In the present case, a 'selfish' autocatalyst, (COZn)2, is embedded in a monomer-dimer equilibrium, 2 COZn ´ (COZn)2 that globally leads to a strong cubic autocatalytic effect resulting in highly nonlinear chiral amplification while the template effect ensures a sufficiently high degree of stereoselectivity. Experimentally observed chiral amplification can be reproduced by the model and further predictions of chiral implications in an open flow system are evaluated. Under these conditions, it is predicted that the system passes through a bifurcation scenario in which the racemic state becomes unstable and the emerging optically active state may show kinetic bistability.
 Buhse, T.; Lavabre, D.; Micheau, J. C.; Thiemann, W. Chirality 1993, 5, 341-345; Keszthely, L. Quart. Rev. Biophys. 1995, 28, 473-507; Avalos, M.; Babiano, R.; Cintas, P.; Jiménez, J. L.; Palacios, J. C. Tetrahedron: Asymmetry 2000, 11, 2845-2874; Kondepudi, D. K.; Asakura, K. Acc. Chem. Res. 2001, 34, 946-954.
 Soai, K.; Shibata, T.; Morioka, H.; Choji, K. Nature 1995, 378, 767-768; Soai, K.; Shibata T.; Sato, I. Acc. Chem. Res. 2000, 33, 382-390; Blackmond, D. G.; McMillan, C. R.; Ramdeehul, S.; Schorm, A.; Brown, J. M. J. Am. Chem. Soc. 2001, 123, 10103-10104; Sato, I.; Omiya, D.; Tsukiyama, K.; Ogi, Y.; Soai, K. Tetrahedron: Asymmetry 2001, 12, 1965-1969.
 Buhse, T. Tetrahedron: Asymmetry 2003, 14, 1055-1061.
 Rivera Islas, J; Pimienta, V.; Micheau, J. C.; Buhse, T. Biophys. Chem. 2003, 103, 191-200; Rivera Islas, J; Pimienta, V.; Micheau, J. C.; Buhse, T. Biophys. Chem. 2003, 103, 201-211; Rivera Islas, J; Micheau, J. C.; Buhse, T. Origins Life Evol. Biosphere, to be published.
WHEN DID INFORMATION FIRST APPEAR IN THE UNIVERSE?
Juan G. Roederer
University of Alaska-Fairbanks
Fairbanks AK 99775,
The Abdus Salam
International Centre for Theoretical Physics
To answer this question it is necessary to define the concept of information in a strictly objective and general way, detached from human artifacts and related algorithms and semantics, and not based on any mathematical formula. To accomplish this we turn to the concept of interaction as the primary concept. We identify two fundamentally different classes, with information and information-processing appearing as the key discriminator: force-field driven interactions between elementary particles and ensembles of particles in the macroscopic physical domain, and information-based interactions between certain kinds of complex systems that form the biological domain. We shall argue that in an abiotic world, information plays no role; physical interactions just 'happen', they are driven by energy exchange between the interacting parts and do not require any operations of information processing. Information only enters the non-living physical world when a living thing, or an artifact constructed by an intelligent being interact with it. In information-based interactions, a form or pattern, not energy or force, is the controlling factor. They comprise biomolecular information processes controlling the metabolism, growth, multiplication and differentiation of cells, and neural information processes controlling animal behavior and intelligence. The only way new information can appear is through the process of biological evolution and, in the short term, through sensory acquisition and the manipulation of images in the central nervous system.
Clearly, only physical systems, albeit complex ones, are involved in information-driven interactions; what appears to be irreducible to presently known physical laws, though, is the way the mechanisms responsible for information-driven interactions actually arise in the natural world. The ultimate question of the origin of biological information is how under prebiotic conditions the nucleotide sequence of the protogene was selected out of innumerable, energetically equivalent, alternatives. In summary, to answer the question in the title: during the evolution of the Universe information begins when and where life begins.
DYNAMICAL EVOLUTION OF EXOPLANETS IN RESONANCES
Andrea Sanchez and Julio A. Fernandez
Departamento de Astronomia, Facultad de Ciencias
The global properties of the 101 extrasolar planets (or exoplanets
for short) so far discovered, which include 88 single-planets and
11 multiple-planet systems, are discussed and compared with our
standard ideas of planet formation, as have been developed for
explaining the main features of our solar system.
The discovered exoplanets have masses around that of Jupiter or
larger but, in sharp contrast with Jupiter, most of them are
close to their central stars and have large eccentricities.
The different alternatives that could explain why the discovered
exoplanets have orbital properties so different from those of the
Jovian planets are analyzed, as well as the dynamical stability
of multiple planet systems, In particular those having two planets
locked in the 2:1 mean-motion resonance.
Since the current most widely used search technique (spectroscopy)
strongly favors the discovery of massive planets close to their
central stars, it is possible that they are very weird
cases, uncommon in comparison with regular planetary systems like ours.
DIVERSITY OF MICROBIAL LIFE ON EARTH AND BEYOND
P.O.Box 1132, Efrat 90435, Israel.
Microbial Life occurs in all environmental conditions on Earth. Microorganisms are abundant not only in "normal" environments but also thrive under very harsh habitats. These organisms that are found at the edge of the living limits have been designated as extremophiles. Such microbes have been observed in various severe conditions (from the anthropocentric point of view) far from the typical, "regular" known conditions of Life.
Those extremophiles that grow in more than one rigorous factor are termed Polyextremophiles (such as Prokaryotes under high pressure and low temperature, or those Bacteria, Archaea and certain algae under high temperature and low pH ranges). Barophilic thermophiles exist in deep-sea hot vents; other organisms live in soda lakes, which may be saturated with salt while reaching pH values as high as 11-12. Archaea and Bacteria are able to survive and grow in various temperature ranges (from 20 °C [the psychrophiles] to 113°C [the hyperthermophiles]). Some unicellular thermophiles thrive in very acidic (at pH 0-2) solution and other in alkaline media (pH ~ 10 and higher). Some bacteria are resistant to high doses of harmful radiation of UV.
Bacteria occur at the subsurface depths where the temperature and the pressure are very high. In the depths of the ocean are the piezophiles (or barophiles) that grow a few kilometers under the surface. Such weight-bearing microbes have to resist not only high pressures (of several hundreds atmospheres) but also low temperatures (1- 3°C ). It has been reported elsewhere that some algae are able to grow under an atmosphere of pure CO2, while bacteria have been kept alive in ammonia and are well known to thrive in anaerobic conditions.
Life has existed on Earth at least for 3.8 billion years. Assumedly, the atmospheric conditions during the early period on Earth were different from those of today. The Origin of Life may have taken place in the hot sub-surfaces of Earth and under oceanic hydrothermal vents. Under such conditions, the first pioneers of Life would have been protected from the harmful UV irradiation and shielded from the inter-celestial rocks and meteorites bombarding young Earth.
Thus, the extremophiles could represent the first microorganisms on Earth with their severe and ancient environments. Furthermore, they could perhaps also serve as models for living microbes under the harsh conditions that exist on extraterrestrial bodies, such as on our neighboring planet Mars, or on the Jovian satellite Europa or even on Titan, the moon of Saturn.
Oren, A. and Seckbach, J. 2001. Oxygenic photosynthetic microorganisms in extreme environments. In: J. Elster, J. Seckbach, W. Vincent, and O. Lhotsky (eds.). Algae and Extreme Environments-Ecology and Physiology. Nova Hedwigia Beiheft 123: 13-31.
Seckbach, J. (ed.) 1999. Enigmatic Microorganisms and Life in Extreme Environments. Kluwer Academic Publishers, Dordrecht, The Netherlands.
Seckbach, J. (ed.) 2000. Journey to Diverse Microbial Worlds, Kluwer Academic Publishers, Dordrecht, The Netherlands.
Seckbach, J and Oren, A. 2003/4.
Introduction to the extremophiles, In: J. Seckbach (ed) Origins,
Kluwer Academic Publishers, Dordrecht, The Netherlands (in press).
EXOBIOLOGY OF TITAN
Michael B Simakov
Group of Exobiology, Institute of Cytology RAS, Russia
Titan, the largest satellite of Saturn has a dense nitrogen atmosphere and a large quantity of liquid water under ice cover and so has a great exobiological significance. The putative internal ocean along with complex atmospheric photochemistry provide some new exobiological niches on this body: (1) an upper layer of the internal water ocean; (2) pores, channels and pockets filled with brines inside of the lowest part of the icy layer; (3) the places of cryogenic volcanism; (4) set of caves in icy layer; (5) the brine-filled cracks in icy crust caused by tidal forces; (6) liquid water pools on the surface originated from meteoritic strikes; (7) the sites of hydrothermal activity on the bottom of ocean. All conditions needed for exobiology - liquid water, complex organic chemistry and energy sources for support of biological processes - are on the Saturnian moon. All these environments will be considered along with properties of many kinds of Earth extremophiles which could
survive in such environments. Possible metabolic processes, such as nitrate/nitrite reduction, sulfate reduction and methanogenesis could be suggested for Titan. Excreted products of the primary chemoautotrophic organisms could serve as a source of the nutrients for other types of microorganisms (heterotrophes).
EXTRATERRESTRIAL IMPACTS ON
EARTH AND EXTINCTION OF LIFE
IN THE HIMALAYA
Vinod Chandra Tewari
Wadia Institute of Himalayan Geology, India
The Abdus Salam ICTP, Italy
The comets, meteorites and asteroids have collided with the Earth throughout geological history. The mass extinction at Permian Triassic boundary and Cretaceous Tertiary boundary is strongly supported by the extraterrestrial asteroidal impact theory in the Indian Himalayan sequences well exposed at Spiti in Western Himalaya and Um Sohryngkew section in Meghalaya, northeastern Himalaya. The Carbon isotopic and palaeobiological events suggest extraterrestrial impacts at P/T and K/T boundaries all over the world. The early evolution of life, its diversification, carbon isotope chemostratigraphy, amino stratigraphy and extinction events have been discussed from the Indian Himalaya.
THE HABITABILITY OF THE NEAREST STARS TO COMPLEX LIFEFORMS
Margaret C. Turnbull
University of Arizona, Steward Observatory, 933 N. Cherry Ave, Tucson, AZ, 85721, USA
Jill C. Tarter
SETI Institute, Mountain View, CA, USA
In this presentation we will take a look at the Solar Neighborhood from the perspective of biology, in order to decide which systems are more likely to be habitable to complex lifeforms. We define a "habstar" as a star whose physical properties make it a good host for planets bearing life like that found on Earth. For a star to be granted "habstar" status, it must satisfy an extensive list of criteria which we have formulated based on our knowledge of life on Earth and the characteristics of the Earth-Sun system. These criteria can be translated into observable stellar characteristics which include stellar age, spectral type, variability, metallicity, stellar kinematics, multiplicity and the presence of known giant planets. Here we describe each of these characteristics and discuss its relevance to life, and we will show how we created criteria for selection of "habstars" to assemble target lists for the Terrestrial Planet Finder and for the Search for Extraterrestrial Intelligence.
In order to carry out this analysis, a vast amount of astronomical data was required. We began this project with the Hipparcos Catalogue, a database of about 120,000 stars whose distances have been accurately determined via parallax measurements. We then supplement this database with data from many other catalogs, each of which provides some information about the stellar characteristics listed above. While it is not possible to know for sure whether any given star has all the requirements for a habitable environment (including terrestrial planets in the habitable zone), we can use these data to eliminate stars that have one or more undesirable characteristics. After doing so, we find that, to the best of our current knowledge, there are at least 17,000 stars within about 1,000 light years that could host complex life. This list comprises the new target list for use with SETI's Allen Telescope Array.
This type of work is unusual in that it inspires discussion of an extremely wide array of astronomical, planetary, and biological topics (e.g., extrasolar planets, galactic structure, supernovae, the Solar Cycle, climate change, plate tectonics, the origin of life, evolution of complex life, etc), and it engages a broad cross-section of the scientific community. From the student's perspective, this exploration requires a combination of imaginative thinking with critical analysis. In the process of carrying out this work, it has become clear that we have very much to learn about even the nearest stars, about the history of life on Earth, and about how our own technological civilization came to be.
SULPHATE VOLUMES AND THE FITNESS OF SUPCRT92 FOR CALCULATING DEEP OCEAN CHEMISTRY
Steven Vance1, Everett Shock2, Tilman Spohn3
1 University of Washington, Seattle, Washington, USA. email@example.com
2 Arizona State University, Tempe, Arizona, USA.
3 Westfälische Wilhelms Universität, Münster, DE.
Comparing experimentally obtained volumes for dilute solutions of sodium sulphate obtained at high pressure and temperature, we show that the supcrt92 program for modeling aqueous chemistry accurately predicts solution properties for all measured temperatures, but fails in the pressure range above 2000 bar. A fix to the governing equations is not readily apparent. However, accuracy to 2000 bar is sufficient for simulating the formation and stable composition of Europa's ocean, if not for the deeper oceans in Ganymede or Callisto. In this way having validated supcrt92 as a tool for explorating Europa's ocean in both the regimes of pressure and temperature, we discuss a calculation of temperature and composition in the ocean. The new calculation is based on pressure distribution dictated by the assumption of hydrostatic equilibrium. Temperature and composition are based on tidal dissipation in Europa's mantle and ocean by Hussman (2003), differentiation as estimated by Sohl et al (2002). We then look at the implications for ecosystems at the ocean's ceiling and floor.
HUSSMAN, H., 2003. Europa's Ocean and the Orbital Evolution of the Galilean Satellites. Dissertation Thesis, Institut für Planetologie, University of Münster.
SOHL, F., T. SPOHN, D. BREUER,
and K. NAGEL 2002. Implications from Galileo observations on the
interior structure and chemistry of the Galilean satellites. Icarus,
CHANCE OR DESIGN IN THE ORIGIN OF LIVING BEINGS
AN EPISTEMOLOGICAL POINT OF VIEW
Rafael Vicuña 1 and Alejandro Serani-Merlo 2,
1. Pontificia Universidad Catolica de Chile
and Millenium Institute for Fundamental and Applied Biology, Chile,
2. Facultad de Medicina,
Universidad de los Andes, Santiago, Chile.
The fact that the natural world is primarily composed by living and non-living entities constitutes one of the humankind commonsense most ancient spontaneous intuitions. The adequate intellectual understanding and the formal conceptual expression of the uniqueness of living beings, has intrigued biologists and natural philosophers at least since the time of the first Greek naturalists.
The question about the origin of living beings was always viewed then -as it is also nowadays-, as tightly linked to the question about the definition and explanation of the uniqueness of life. If living beings are no more than complex material devices, organized fortuitously by the free interaction of blind mechanical forces, and whose survival was submitted to natural selection, as Empedocles first sustained, then the complete understanding of the origin of life must lie on strictly mechanical explanations. If, on the other side, living beings are unique natural entities, formally different from non-living beings, even if materially composed by them, as philosophers like Plato and Aristotle sustained, then the explanation of their origins must revert to supra-mechanical causes in addition to mechanical ones. These supramechanical causes not being conceived as supramechanical forces as in later vitalism but as real formal aspects, as opposed to material aspects, of physical realities.
In the Greek non-creationist cosmological context, the particular origin of life reverted to chance -in the materialistic view-, and to some kind of intentional non-mechanical formal causality -in the non-materialistic view-. Underlying the many nuances that the huge development of modern biology has introduced through the centuries, to the statement of the problem, the opposing philosophical views seem to remain virtually untouched. Some authors, in the line of Oparin and others, adhering explicitly to philosophically materialistic views, have tried to find in the experimental evidences that modern science provides the grounding for their theoretical speculations on a purely mechanistic explanation for the origin of life. On the other hand, and also intending to ground their speculations in data provided by contemporary biological knowledge, an increasing number of authors try to substantiate the thesis that the origin and diversification of living beings on earth would have been impossible without the recourse to other kind of causes (non-reductionism) or the intervention of an intentional intelligent cause (creationism).
In this study we don't intend to arbitrate the ontological dispute between materialistic and non-materialistic positions; we only intend an epistemological clarification that could open the way to conciliate in some way both views, recognizing the part of truth that both positions seem to contain.
We propose to distinguish in actual discussions on the origin of life on earth at least four different epistemological categories of statements: a) direct experimental evidence; b) interpretation of primary experimental data through theoretical modelling; c) interpretation of primary evidence through ontological or philosophical speculation; d) paleontological theoretical speculation based on the three previous kind of statements.
Considering that the rise of living beings from material components is not a directly verifiable event, we must accept that the origin of life is at present out of the reach of experimental evidence. Actual experimental data then provides nowadays only indirect evidence for theoretical reasoning on levels b), c) and d) previously described.
We sustain in this proposal that paleontological speculations, based on actual experimental data are not necessarily contradictory with philosophical reasoning also based in primary experimental evidence. What seems to be indeed contradictory are mechanistic versus non mechanistic philosophical statements. If what we affirm is correct, that means that it could be accepted as legitimate for a biologist, -while thinking 'paleontologically'-, to reason purely or mainly on strictly empirical basis, while on the other hand, the same person thinking as a philosopher, could perfectly reason on non-mechanistic or intentional design grounds. Only if a biologist affirm as a philosopher the truth of an empirical view, an intelligent design position can be regarded as contradictory to his statements.
In summary, we affirm that it
is in principle non-contradictory for a biologist to reason as
a paleontologist on strictly empirical terms, while thinking as
a philosopher on intentional design grounds. If intentional design
thinking is really true or not, that must be decided on strict
philosophical terms, not on scientific ones.
ADSORPTION AND CATALYSIS OF NUCLEOTIDE HYDROLYSIS BY PYRITE IN MEDIA SIMULATING PRIMEVAL AQUEOUS ENVIRONMENTS
Adalberto Vieyra1,#, Ana C. Tessis1, Mila Pontes Buarque1, José A. Bonapace2, Marisa B. M. Monte3, Hélio Salim de Amorim4 and Fernando de Souza Barros4
1Instituto de Biofísica Carlos Chagas Filho, 2Instituto de Química and 4Instituto de Física, Universidade Federal do Rio de Janeiro; 3Centro de Tecnologia Mineral, Ministério da Ciência e Tecnologia, Rio de Janeiro, Brazil.
Minerals of Fe/S have been implicated in different catalytic processes during chemical evolution. In this communication we report work regarding Fe/S-nucleotides interaction. We investigated whether pyrite (FeS2) can adsorb nucleotides and oxo acids in the potentially mild prebiotic conditions that could have existed in the neighborhood of hydrothermal vents. It is shown that pyrite strongly adsorbs adenosine 5'-monophosphate (5'-AMP) and adenosine 5'-triphosphate (ATP) in an artificial medium that simulates that environment. Adsorption of nucleotides is modulated by divalent cations, pH, molecules of high dipolar moment (such as cyano compounds), and by acetate an organic precursor of complex metabolic pathways. The adsorption of nucleotides also depends on the net surface charge of the mineral modulated by the pyrite-aqueous solution interface. Upon adsorption, FeS2 catalyzes the sequential hydrolysis of the g and b phosphoanhydride bonds of ATP, with a kinetics and metal-dependence that could have pre-empted by more evolved energy-transducing systems. These results show that complex and flexible iron-sulfide/biomonomers interactions - in one of the proposed primordial environments - could have played a significant role during chemical evolution.
# Author for correspondence, e-mail: firstname.lastname@example.org; FAX: +55-21-22808193
Financial support: CNPq, FUJB-UFRJ, Finep (Brazil)
QUASAR ABSORPTION LINE SYSTEMS AND ASTROBIOLOGY
Osservatorio Astronomico di Trieste
Istituto Nazionale di Astrofisica
Quasar absorption line systems probe the diffuse gas in the universe and are observed over a large interval of cosmic time, up to ~12 Gyr before the present. Most absorptions arise in the intergalactic medium where the physical conditions are too harsh to host life. However, the absorptions with the highest column density of neutral gas, called Damped Lyman alpha systems (DLAs), arise inside galaxies observed at the early stages of their evolution and offer new perspectives in studies of astrobiology. In fact, as I show in this contribution, observations of DLAs provide unique data on the build-up of biogenic elements, molecules and dust in galaxies, as well as on the effects of ionizing radiation fields. The analysis of these data as a function of cosmic time can provide fresh clues in the search for continuously habitable zones.
ISOTOPIC EVIDENCE FOR MICROBIAL SULFATE REDUCTION AND METHANOTROPHY DURING THE LATE ARCHEAN, WITWATERSRAND BASIN, SOUTH AFRICA
A. Erik Boice, Brett J. Tipple and Lisa M. Pratt,
Department of Geological Sciences, Indiana University,
1001 East 10th Street, Bloomington, IN 47405
Stable isotope ratios were determined for carbon (d13C) in organic matter and carbonate and for sulfur (d34S) in pyrite for a stratigraphic profile from a core containing 60 meters of the late Archean Booysens/Kimberly (B/K) Shale Formation and a portion of the underlying Krugersdorp Quarzite Formation. The studied core was collected at a subsurface depth of 1.8 km in Evander shaft #8 operated by Harmony Gold Inc. The Evander sub-basin is located on the northeast rim of the Witwatersrand Basin. Silty shales are the dominant lithofacies in the core but interbedded siltstones and several meters of underlying gray quartzites are present. Carbonate (Ccarb) and Organic carbon (Corg) contents in core samples range from <0.05 to 2.26 wt% and <0.05 to 0.42 wt%, respectively. Values of d13C for organic matter (d13Corg) and carbonate minerals (d13Ccarb) range from -42 to -35 and 14.6 to -10.1, respectively. Distinct negative shifts in d13Corg values occur in laminated clay-rich intervals while positive shifts occur in carbonaterich intervals. Values of d34S for Cr-reducible disulfide minerals (predominantly pyrite) range from -3.2 to +2.3. The most negative d34S values occur in the laminated intervals that contain the most negative d13Corg values. d13Ccarb values lower than -10 are inferred to reflect bicarbonate derived from methane. Microprobe imaging shows partial to complete chlorite replacement of original rhombohedral carbonate grains. The combined carbon and sulfur isotopic evidence suggest a thriving community of methanotrophic and sulfate-reducing bacteria in laminated, muddy sediment deposited during maximum marine flooding of the Witwatersrand Basin.
THE ROLE OF CLAY MATERIAL IN SHIELDING DNA AGAINST X-RAY RADIATION.
Ciaravella A., Barbera M., Micela G., Candia R., INAF-Osservatorio Astronomico, Palermo
Scappini F, ISMN-CNR, Bologna
Cecchi-Pestellini C., ISAC-CNR, Firenze
Franchi M., Gallori E., Universita', Firenze
X-ray experiments have been conducted on water solutions of free DNA and clay absorbed DNA. The level of damage has been analyzed using biological transformations. Results will be presented and discussed in the context ofthe origin of life.
PREBIOTIC CHIRALITY TRANSFER FROM EXTRATERRESTRIAL Ca-TETRASUBSTITUTED a-AMINO ACIDS TO PROTEIN AMINO ACIDS
Marco Crisma a, Alessandro Moretto a, Fernando Formaggio a, Claudio Toniolo a, Bernard Kaptein b, Quirinus B. Broxterman b
a. Institute of Biomolecular Chemistry, CNR, Department of Organic Chemistry, University of Padova, Via Marzolo 1, 35131 Padova, Italy
b. DSM Research, Life Sciences, Advanced Synthesis and Catalysis, P.O. Box 18, 6160 MD Geleen, The Netherlands
A recent analysis of the amino acid content of the Murchison meteorite, fallen over Australia in
1969, revealed the presence of four chiral Ca-tetrasubstituted a-amino acids, namely isovaline (Iva), Ca-methyl norvaline (Me)Nva], Ca-methyl isoleucine [(aMe)Ile], and Ca-methyl alloisoleucine [(aMe)aIle] with a small, but significant, L(S) enantiomeric excess (up to 9%). Related findings in the protein amino acid fraction were considered of no significance in view of a possible terrestrial contamination. On the contrary, this possibility is quite remote for these Ca-tetrasubstituted a-amino acids, the occurrence of which on terrestrial compounds was reported only for Iva. Moreover, Ca-tetrasubstitution protects amino acids against racemization. These results suggest that Ca-tetrasubstituted a-amino acids of extraterrestrial origin could have been the homochirality seeds for life in our planet. However, this hypothesis implies that the enantiomeric excesses would have been somehow transferred from Ca-tetrasubstituted a-amino acids to protein amino acids. In this connection, we have planned a detailed study aimed at determining if and how derivatives or peptides based on Ca-tetrasubstituted a-amino acids could have reacted with protein amino acids and favoured one of their enantiomers over the other.
In this Communication we report on the synthesis and conformational studies of the Iva, (aMe)Nva, and (aMe)Val, homochiral homopeptides. These Ca-tetrasubstituted residues bear either a linear [Iva and (aMe)Nva] or a b-branched [(aMe)Val] side chain. Solution (FT-IR absorption, CD, 1H NMR) and crystal-state (X-ray diffraction) conformational analyses indicate that these homo-peptides tend to fold in b-turn and 310-helical structures (depending upon main-chain length).
Homochiral homopeptide sequences from Iva, (aMe)Nva, and (aMe)Val, activated as Ac-(AA)n-OXL [Ac, acetyl; OXL, 5(4H)-oxazolone; n = 2-8] were allowed to react with a racemic mixture of a protein amino acid, H-D,L-Val-OMe. The competitive formation of the resulting diastereomers was quantified. The effects of temperature and reaction time were also examined. We have found variable amounts of diastereomeric excesses [up to 58% for the longest (aMe)Val homo-peptides]. Our results clearly show that the incorporation of the heterochiral protein amino acid is increasingly preferred with: (i) increasing difference in size between the two side chains of the Ca-tetrasubstituted a-amino acid, and (ii) increasing main chain length of the peptide oxazolone, which in turn favours the onset of stable secondary structure elements.
Thus, it is reasonable to conceive a racemic primordial soup of protein amino acids which in the long run is converted to a soup with a more and more abundant L enantiomeric excess due to the depletion of the other isomer by the Ca-tetrasubstituted oligomers. At this stage, various possible mechanisms of peptide bond formation may have further amplified this phenomenon, eventually producing the first functional proteins.
SOME STATISTICAL ASPECTS RELATED
TO THE STUDY OF TREELINES
IN PICO DE ORIZABA
Instituto de Ciencias Básicas. Universidad Veracruzana
Carr. Xalapa-Ver., Km. 3.5, Las Trancas, Xalapa, Ver., MEXICO
CHRISTOPHER P. MCKAY
NASA-Ames Research Center
Moffett Field, CA 94035, USA
Laboratorio de Química de Plasmas y Estudios Planetarios
Instituto de Ciencias Nucleares, UNAM, Circuito Exterior,
Ciudad Universitaria, Apartado Postal 70-543, MEXICO
Pico de Orizaba, Mexico's highest peak, is the fourth highest volcano in the Northern Hemisphere, it has a glacier on the north face and it has the highest tree line in the world (> 4200 m). Pico de Orizaba (19º N) has environmental conditions that probably could have occurred in ancient Mars. Therefore, related to the survival of ecosystems in extreme environments, with possible applications to life on Mars, we started to monitor the mountain in several sites, above, below and within the tree line of the domineering species P. hartweggi. Since March of 1999 we have been studying physical and chemical properties of soil as well as those of microbial activity. Of particular interest is to study tree lines at thermal gradients, for which, soil temperatures at various depths, as well as external temperatures, tree-trunk temperatures and other measurements such as air humidity, etc., are being recorded hourly since then, in an ongoing process to continue for several years. The present is a report of some of the continuing statistical analysis performed on the data, in an effort to detect spatial and temporary patterns.
THE HUNT FOR "BIOLOGICALLY
SPONTANEOUS FOLDING OF RANDOM RNA OLIGOMERS
Marco Franchi*, Davide De Lucrezia§, Cristiano Chiarabelli§, PierLuigi Luisi§, Enzo Gallori *
Department of Animal Biology and Genetics, University of Florence - Florence (Italy)
§ Institute of Polymers, Swiss Federal Institute of Technology, ETH Zurich - Zurich(Switzerland)
The probability of occurrence of biopolymers with a well defined steric conformation is one of the central questions concerning the origin of life on Earth. In fact, whatever was the nature of primitive "biological" polymers, their chemical activity and specialized functions depended on the acquisition of durable and stable secondary and tertiary structures.
Because of the possible pivotal role of RNA in the evolution of life on Earth, we have studied the folding properties of RNA oligonucleotides with random sequences. We developed a plasmid library for in vitro transcription of random RNAs, 150 nucleotides long. The resulting RNA molecules were tested for their sensitivity to S1 nuclease at different temperatures ranging from 37 to 60°C in order to evaluate their ability to form internal double helices and to acquire secondary and tertiary structures.
Preliminary results of these studies suggest that most (~70%) random oligomers acquired a secondary structure stable up to 50°C but lost their folding at higher temperatures. Interestingly, a small percentage (~9%) of the oligomers were very stable even at relatively high temperatures (55-60°C), suggesting a possible role of these thermostable steric structures in the hot environments of the primeval Earth.
CHARACTERIZATION OF EXTRASOLAR PLANET CANDIDATES
Jose Gallardo and Dante Minniti.
Departamento de Astronomia y Astrofisica,
Facultad de Fisica,
P. Universidad Catolica de Chile.
Av. Vicuna Mackenna 4860.
We report photometric classifications of 62 stars where OGLE found transits in order to classify the most promising candidates to have extrasolar planets. We use the difference of stellar flux dF, delivered by OGLE data, and the stellar radius R_star, derived from the spectral type found by our IR photometry, to determine the companion's radius R_planet. Besides, we present a stellar environment study to verify properties of these candidates like distance, metallicity and stellar populations. Follow up spectroscopic observations will enable us to obtain their masses and to discriminate among white and brown dwarf and giant planets.
PROPOSING A UNITED NATIONS SECRETARY GENERAL SETI INTERNATIONAL ADVISORY BOARD
Department of Mechanics, Politecnico di Torino,
C. Duca degli Abruzzi 24, 10129, Torino, Italy
email@example.com / fax: ++39 011 564 6999
Advisor to the United Nations Secretary General at the Level of Under-secretary New York USA
Department of Physics, University of Torino, Torino, Italy
Non Govermental Peace Strategies Project Geneve Switzerland
SETI's Post-Detection Protocols have recently identified a novel means of interaction between SETI and the United Nations.
Through this proposal, the Italian
SETI Study Center hopes to realize the following:
1) The preparation of an ad hoc study on SETI by an international panel of experts of various disciplines for the United Nations, addressed to the Secretary General;
2) The identification and formalization of the role of the United Nations Secretary General and his International Advisory Board in the functions of decision-making, management of/communication with the international media system vis-à-vis the possible detection of artificial signals of proven extraterrestrial origin.
SETI's work program includes the
1. TARGET: To create an effective, temporary board for the United Nations Secretary General, with information and situation support capabilities per SETI.
To prepare a state of the art document on SETI, covering all possible aspects (including scientific, philosophical, social, media, intelligence and security aspects);
To update this document on a bi-annual basis;
To act as the United Nations Secretary General's situation support staff in instances of extraterrestrial signal detection and, in particular, to assist him in the decision-making process upon successful detection of such signals.
The board will, in effect, develop, and make official, the contents of the SETI Post-Detection Protocols, expanding its activity to managing communication of any signal detection to the international media system.
3. COMPOSITION of the International
Advisory Board: experts with internationally recognized credibility
and competence in the following areas:
Astrophysics and Cosmology
Astronautics and Space Exploration
Mathematics and Informatics
International Space Law
Philosophy of Science
Intelligence and Military Aspects
4. AGENDA: The International Advisory Board expects to meet every two years to update and follow-up on current needs.
FUNDING: The funds required to
create, maintain and support the activities of the international
advisory board will not be provided by the United Nations but
rather will be raised in the private sector, through various foundations,
companies and associations with adequate international standing.
EFFECTS OF NON-CARBONACEOUS METEORITIC EXTRACTS ON THE GERMINATION, GROWTH AND CHLOROPHYLL CONTENT OF EDIBLE PLANTS
VICENTE MARCANO1, PAULA MATHEUS1, CESYEN CEDEÑO2, NELSON FALCON3 AND ERNESTO PALACIOS-PRÜ1,4
1 Evolutionary Biology and Chemistry Laboratory, Electron Microscopy Center, University of the Andes, P. O. Box 163, Mérida, Venezuela.
2 Crystalography Laboratory, Faculty of Sciences, University of the Andes, Mérida, Venezuela.
3 Department of Physics, Faculty of Science and Technology, University of Carabobo, Valencia, Venezuela.
4 International Institute of Advanced Studies, Simón Bolívar University, Caracas, Venezuela.
Several scenarios have been conceived in order to establish eventually human settlements in space stations or on planetary bodies or satellites, using indigenous space resources. Nutrients for plant cultures in space could be obtained mining asteroids or collecting micrometeorites. Carbonaceous and non-carbonaceous meteorites contain nutrients needed for biological activity. Experiments utilizing non-carbonaceous material are not known. Selection of edible plants by human settlements in the space should take in account their capacity to compensate the effects that the unfiltered solar radiation, galactic radiation and negligible gravity would produce on humans. We focus our investigation on the effects that non-carbonaceous meteoritic extracts could has on the germination and growth of these plants and the ability of non-carbonaceous meteoritic resource to serve as nutrient source for young plants having edible uses. Selected plants were two dicotyledons (Lycopersicon esculentum and Daucus carota) and one monocotyledon (Zea mays). Solution cultures were developed using seeds and seed-embryos. Meteoritic powder was obtained from the Vigirima mesosiderite, which was analyzed by X-ray diffraction and atomic absorption spectrometry (AAS).
Results showed that extracts having variable concentrations of meteoritic matter produced an earlier germination in some plant species but the increase of the concentrations produced a decreased germination. However, total germination rate was higher in the presence of meteoritic extracts than in the presence of blanks in the all species. A high metabolic yield in the protein synthesis was seen in dicotyledons utilizing Type-A and B extracts having concentrations of 4.16-8.33 x 103 mg l-1. Phaeophytinization index and chlorophyll a/b ratio, suggested an negative effect of the heavy metals or acidic ions over the photosynthetic activity when extracts having high meteoritic concentrations were utilized. However, a higher chlorophyll (a) production in comparison to that of chlorophyll (b) was seen in extracts (Type-A and B) having low concentrations of meteoritic matter. On the other hand, Z. mays seed-embryos growing in extracts (Type-D) having 3.53 x 104 mg l-1 of meteoritic matter showed a protein production (9.81 x 10-2 mg protein mg wet wt.-1) higher than that observed in seed-embryos coming from extracts having lower concentrations. However, in Murashige medium, the seed-embryos exhibited a enhanced growth and a relatively higher protein production (10.3 x 10-2 mg protein mg wet wt.-1). Further, chlorophyll (a+b) synthesis was higher in Murashige medium than in meteoritic extracts but chlorophyll a/b ratio was < 1 in the all extracts and blanks.
Our results suggest the usefulness of the non-carbonaceous meteoritic resource as a complementary soil component or fertilizers for culture of edible plants in space human settlements and mainly for the production of young plants due to the positive metabolic effects on the chlorophyll synthesis, mitochondrial metabolism and cellular division caused by PO43-, Fe2+, Cu2+ and Ca2+ ions. Earlier germination responses obtained in the experiments showed the possibilities to utilize in space germination chambers having wet substrates containing meteoritic-powder solutions to obtain a higher number of seedling in a minimum degree of time. Utilization of seed-embryos could be considered an efficient alternative to develop in space stations or human settlements on Mars or Moon. These results reveal also the biological potential of the non-carbonaceous meteoritic matter for the growth of organisms in the early Earth, Mars, and probably in other planetary bodies beyond our Solar system.
HOW ADVANCED IS ETI?
ARE SCIENTIFIC AND TECHNOLOGICAL PROGRESS LIKELY TO BE ENDLESS?
Pontifical University of the Holy Cross of Roma
V. Montevideo 2A/-6, 16129 Genova (GE) - Italy
One of the most widespread commonplace in discussing about the possible existence of other technological civilizations is that they should be very more advanced than ours.
At a cosmic scale, indeed, mankind was born just yesterday. So, it is very likely that almost any other civilization we could ever detect will be much older than ours. But does it necessarily imply that it should be also much more advanced?
Since we are just at the dawn of our technological age, but nonetheless in only four centuries have achieved such a great progress, a positive answer may seem to be obvious. But, in fact, this implies the assumption that both scientific and technological progress are endless processes, which is not obvious at all. In this paper this point will be discussed, with the help of two diagrams analyzing the only example of scientific and technological progress we know, that is the one of our own terrestrial society.
PREBIOTIC POLYMERIZATION OF AMINOACIDS. A MARKOV CHAIN APPROACH
S. Ramos-Bernal1, G Mosqueira2 and A. Negron-Mendoza1
1Instituto de Ciencias Nucleares, UNAM, A.P. 70-453, Mexico, D.F 04510
2Dirección General de Divulgación de la Ciencia, UNAM. Cd. Universitaria, A.P. 70-487, 04510
México D.F., México.
The principle of self-ordering of amino acids, as related to the origin of life research, has been extensively studied and interpreted by S. Fox and collaborators (Fox and Dose, 1977). Such principle establishes that the reactivity between different amino acids is not even.
The relevance of the self-ordering principle to the emergence to minimal self-reproducible chemical systems has been already analyzed in probabilistic terms. These considerations concluded that the polymerization phenomena associated to the origin of life had to be strongly biased. Otherwise the probability of nucleation of a "minimum life would be excluded (Mosquiera, 1988).
In the present work, we study the Markov chain approach for the oligomerization of amino acids based on the physicochemical and volume differences among reacting amino acids. The results found may be of importance as it makes more accessible the replication of minimal chemical machinery compatible with life processes.
Fox, S. and Dose, K. (1977), Molecular evolution and the origin of life, Marcel Dekker, Inc., New Yor.
Mosqueira, G. (1988), Origins
of Life and Evol. Biosphere, 18, 143-156.
ANALYSIS OF THE WORKS OF THE
ERNST HAECKEL (1834-1919)
ON THE ORIGIN OF LIFE
Centre Alexandre Koyré
Muséum national d'Histoire naturelle
57 rue Cuvier - F-75005 Paris
e-mail : firstname.lastname@example.org
During the second part of the nineteenth century, the problem of the emergence of living beings was much debated. The theory of natural selection (The Origin of Species, Darwin, 1859) led to wonder about the beginning of life, while the theory of spontaneous generation for microorganisms still persisted. However, Pasteur's series of experiments (Mémoire sur les corpuscules organisés qui existent dans l'atmosphère, Annales des Sciences Naturelles, 1861) proved that preexistent germs in the atmosphere were the response to the question of spontaneous generation and then, that life was always antecedent to life. Despite this demonstration, however, many scientists adopted the evolutionist point of view while accepting that a primitive life could arise from continual spontaneous generation. Therefore, because of this link between evolution and spontaneous generation (at some period or other of the Earth's history) it appears that, between 1860 and the end of the nineteenth century, the question of the origin of life was rather complex.
In Germany, the materialist philosophers and the naturalist Ernst Haeckel (1834-1919) were enthusiastic about Darwin's theory precisely because one type of spontaneous generation (abiogenesis: organic matter- in terms of belonging to living organisms- emerging from inorganic matter) and the unification of the organic and inorganic world into " one great fundamental conception "were implied (Farley, 1977). Acceptance of abiogenesis became naturally a cornerstone of materialist philosophy. In several of his numerous writings, Haeckel took an active interest in the topic of the origin of life (a primeval abiogenesis, in a distant past). Haeckel's views on the origin of life mainly came from his philosophy (monism) and his concept about the nature of the simplest organisms, made of one single substance, named protoplasm.
In this work, we propose to analyze more precisely the following Haeckel's writings:
- Generelle Morphologie der Organismen (General Morphology of Organisms) (1866)
- Natürliche Schöpfungsgeschichte (Natural History of Creation) (1868)
- Die Welträthsel (The Riddles of the Universe) (1899)
- Die Lebenswunder (The Wonders of Life) (1904)
- Farley, J. (1977) Spontaneous Generation Controversy from Descartes to Oparin, The John Hopkins University Press, Baltimore and London.
HORIZONTAL GENE TRANSFER IN THE EVOLUTION OF NITROGEN FIXATION
Janet Siefert, PhD
Department of Statistics MS 138
PO Box 1892
Houston, Texas 77251-1892, USA
Web site: http://www.stat.rice.edu/%7Emathbio/siefert.html
Whole genome sequences for nearly twenty nitrogen-fixing prokaryotes are now available, and we have analyzed each of these organisms for presence of one or more nif (nitrogenase-gene encoding) operons and conserved synteny. Additionally, we have used standard tools of sequence analysis to evaluate the evolutionary history of every characterized gene found in these nif operons and observe that the core genes segregate phylogenetically into the known metal-binding classes (iron-, vanadium-, or molybdenum-containing) of nitrogenase. We have also used molecular phylogenetic techniques to analyze a fourth group of yet-uncharacterized nitrogenase homologs, found in archaea and in a limited number of phototrophic bacteria, that appear to be ancestral to nitrogenase genes and to essential genetic components of chlorophyll and bacteriochlorophyll biosynthesis found in all known phototrophs. This fourth group of nitrogenase homologs may function as an electron sink or possibly as a non-specific detoxyase or reductase, and is likely a relic of some ancient metabolic trait. Here we trace the early origins of nitrogenase genes and the subsequent horizontal gene transfer events that have resulted in the current distribution of prokaryotic nitrogen fixation.
PALAEOBIOLOGY AND BIOSEDIMENTOLOGY OF THE STROMATOLITIC BUXA DOLOMITE, RANJIT WINDOW, SIKKIM, NE LESSER HIMALAYA, INDIA
Vinod Chandra Tewari *+
*Wadia Institute of Himalayan Geology, India
+The Abdus Salam ICTP, Italy
The Mesoproterozoic (Riphean) stromatolite taxa are recorded from the Buxa Dolomite of the Ranjit Window, Sikkim Lesser Himalaya India. The Riphean characteristic taxa are Omachtenia, Colonnella columnaris, Kussiella kussiensis, Conophyton, cylindricus, C. garganicum, Rahaella elongata Tewari, Jacutophyton, Baicalia nova, Tungussia, Jurusania, Inzeria, Gymnosolen, Minjaria, Stratifera and Gongylina. The Neoproterozoic-Terminal Proterozoic (Vendian) stromatolite assemblage Paniscollenia, Aldania, Tungussia, Linella, Colleniella, Linocollenia, Boxonia linked Conophyton, Conistratifera, microstromatolites, Stratifera, Irregularia, Nucleella, digitate stromatolites and oncolites are well developed in the Buxa Dolomite, Ranjit Window, Sikkim and its equivalents (Menga Limestone/Dedza Limestone/Chillipam Limestone) in the adjoining Arunachal and Bhutan Lesser Himalaya. The Mesoproterozoic to Terminal Proterozoic stromatolite diversification has been recorded for the first time from the Buxa Dolomite of the Sikkim Lesser Himalaya, India. The Palaeobiological and biosedimentological significance of the stromatolites in the Buxa Dolomite has been discussed.
CHEMICAL ABUNDANCES OF COMETARY METEOROIDS FROM METEOR SPECTROSCOPY: IMPLICATIONS TO THE EARTH ENRICHMENT
Josep Mª Trigo-Rodríguez 1, Jordi Llorca 2,3 and Joan Oró 4
1 Departament Ciències Experimentals, Universitat Jaume I.
2 Institut d'Estudis Espacials de Catalunya.
3 Departament Química Inorgànica, Universitat de Barcelona.
4 Fundació Joan Oró
The overabundance of comets and chondritic bodies during the first stages of the primeval Solar System produced a constant rain of material over our planet, that could have direct implications to the origin of life in it (Oró 1961). Nowadays we know that cometary matter in these encounters suffers important alteration processes, the collision of comet Shoemaker-Levy 9 with Jupiter provided us interesting information about these violent processes. Probably the most important source of Earth enrichment in volatile and organic compounds has been therefore the constant entry of meteoroids from dense meteoroid streams produced during hard fragmentation processes of their parent bodies. At present, meteor storms are unusual but we believe that fragmentation of comets and chondritic bodies produced dense cometary streams during the first stages of the Solar System. Important evidences have been obtained in the last decade studying young protoplanetary disks. The observation of fast spectral changes in their respective central stars has induced the development of the so-called model of Falling Evaporating Bodies. Only a turbulent stage where minor bodies are in constant fragmentation can be able to explain some of the most important characteristics of these young planetary systems.
Actually, meteor storms are usually produced by relatively long period comets with high inclination orbits that produce violent encounters of the meteoroids with the terrestrial atmosphere. In the past, it is likely that meteor storms were produced from orbits of low inclination and eccentricity, typical of ice and chondritic minor bodies formed in the inner Solar System or perturbed from outer regions due to the high matter density of bodies in the young solar system. An important consequence is that the low geocentric velocities allowed this matter to arrive to the Earth without be completely degraded as occurs for high-velocity meteoroids. We have analysed the temperature and volatilisation processes from the study of spectra of fireballs produced by cometary meteoroids. From these spectra we have derived the relative abundance of Na, Mg, Ca, Si, Ti, Cr, Mn, Fe, Co and Ni in the parent meteoroids by averaging the composition of the radiating gas along their respective fireball paths produced during atmospheric entry. Data reduction and relative chemical abundance were obtained following Borovicka (1993) procedure. According to their orbital elements these meteoroids were principally of cometary origin. We have found important chemical differences between these cometary meteoroids and the 1P/Halley dust analysed in situ by Giotto spacecraft (Jessberger et al., 1988). Between these differences is important to note that the deduced abundances of Si-Mg-Fe are in accordance to the hierarchical dust accretion model developed by Rietmeijer (2002). Moreover, other interesting result is the larger sodium abundance compared to the expected for IDPs and chondritic meteorites. It shows that 1P/Halley can not be used as type sample of cometary dust, suggesting important differences between comets, as was already pointed out by Greenberg (2000).
Finally, we focus our attention into the direct implications that this cometary matter, reaching the atmosphere as meteoroid streams, had in the primeval enrichment of exogenous material into the Earth. Our results support the idea that there are, in fact, substantial chemical differences among comets, probably related with the origin of the different families as was proposed by Delsemme (2000).
Borovicka J. (1993) "A fireball spectrum analysis", Astronomy & Astrophysics 279, 627-645.
Delsemme A.H. (2000) "1999 Kuiper Prize Lecture: Cometary Origin of the Biosphere", Icarus 146, 313-325.
Greenberg J.M. (2000) "From comets to meteors", Earth, Moon and Planets 82-83, 313-324.
Jessberger E.K., J. Kissel & J. Rahe (1988b) "The composition of comets", in Origin and Evolution of Planetary and Satellite atmospheres, 167-191, Univ. of Arizona Press, Tucson, EUA.
Kissel J. y F.R. Krueger (1987), "The organic component in dust from comet Halley as measured by the PUMA mass spectrometer on board Vega 1", Nature 326, 755-760.
Oró J. (1961) "Comets and the formation of biochemical compounds on the primitive Earth", Nature 190, 389-390.
Rietmeijer F. J. M., (2002) "The Earliest Chemical Dust Evolution in the Solar Nebula", Chemie der Erde 62-1, 1-45.
CONSERVED OLIGOPEPTIDES IN RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE LARGE CHAINS : AN EVOLUTIONARY PERSPECTIVE.
P.B.Vidyasagar 1, Pratip Shil 2 and Sarah Thomas 3
1 Professor, Biophysics Section, Department of Physics, University of Pune,
2 Research student, Biophysics Section, Department of Physics, University of Pune,
3 Lecturer, Bioinformatics Center, University of Pune.
carboxylase/Oxygenase (RuBisCO) is the largest multimeric protein
on the Earth and it catalyses the first step in the CO2 assimilation
in photosynthesis. Analysis of RuBisCO large chain sequences from
different species spanning from lower to higher plants (viz. Archea,
Bacteria, Alga and Higher plants) have been carried out using
Bioinformatics techniques viz multiple sequence alignment (CLUSTALW)
and secondary structure prediction tools. Secondary structure
prediction from the Predict Protein package show the occurrence
of conserved oligo-peptides in different secondary structures
in different groups of sequences. The study also reveals the occurrence
of conserved oligopeptides specially '-KDDEN-" and '-SGGIH-'
in almost all the sequences. The advanced analysis and comparison
of these sequences with those from tobacco and spinach (with known
3D structures) reveal the existence of close interaction of these
oligopeptides and other conserved amino acids. The conservation
of the oligopeptides indicates their probable decisive role in
the active site configuration.
The present study reveals that in the evolutionary pathway the RuBisCO large chain sequences have stabilized in higher plants after initial variations in the lower plants.
The present study reveals some of the aspects related to the structural changes during evolution of plants.
INTERSTELLAR DUST AS A TRACER OF ENVIRONMENTS FAVOURABLE TO PLANET FORMATION: EVIDENCE FOR THE EXISTENCE OF A METALLICITY THRESHOLD.
Osservatorio Astronomico di Trieste
Istituto Nazionale di Astrofisica
Dust occupies a central position along the astrophysical route that, starting from the stellar production of chemical elements, leads to the formation of molecules and pre-biotic material in the interstellar space and to the building up of proto-planetary disks around stars. Tracing the formation and evolution of dust in galaxies is therefore an important step in the quest for environments capable of developing life. I report here the results of a study of the dust content in primordial galaxies observed by means of absorption spectroscopy of background quasars. This study provides evidence for the early build-up of dust, consequent to the stellar production of metals, in primordial galaxies seen between ~8 and ~12 billion years before the present. The analysis of the data indicates a severe deficiency of the dust-to-metal ratio in the very early stages of metal production. However, when the metallicity level increases above ~10% of the solar value, the dust content approaches the values typical of the nearby interstellar medium, where planets and life managed to emerge. This suggests that galaxies with metallicities >10% of the solar one may have a dust content sufficient to develop pre-biotic material and planets.
THE ELECTROCHEMICAL CO2 REDUCTION TO FORMATE IN HYDROTHERMAL SULFIDE ORE DEPOSIT AS A NOVEL ABIOTIC SOURCE OF ORGANIC MATTER (A HYPOTHESIS AND THE LABORATORY MODEL).
M. G. Vladimirov1 *, Yu. F. Ryzhkov 2, V. A. Alekseev 2, V. A. Bogdanovskaya 3,
V. A. Otroshchenko 1, and M. S. Kritsky 11 A.N.Bach Institute of Biochemistry, Russian Academy of Sciences (RAS), Moscow; 2 The Russian Federation State Research Center "Troitsk Institute for Innovation and Fusion Research", Troitsk, Moscow Region; 3A.N.Frumkin Institute of Electrochemistry, RAS, Moscow; Russia.
A wide spectrum of electrode potentials of minerals that compose sulfide ores to enable the latter, when in contact with hydrothermal solutions, to form galvanic circuits with cathode potentials up to several volts sufficient for electrochemical reduction of CO2.
Before our study pyrite was not investigated as cathode material, hence the combination of semiconductor properties with the low adsorption activity and a presence of traces of transient metals pointed to this mineral as to a probably good cathode material. The experiments performed demonstrated the increase of cathode current on rotating pyrite electrode in a range of potentials more negative than 800 mV in presence of CO2 and revealed the dependence of this current from the CO2 diffusion rate, temperature and ionic composition of aqueous phase.
The numerous studies of the CO2 reduction on cathode materials other than pyrite have formed the notion on the chemistry of this process. According to it, the reduction process involves an electron tunneling from cathode surface to a CO2 molecule with the production of an active particle, the radical-ion __2- and the further reduction of this radical to formate (and, under certain conditions, to more complex molecules).
To verify our hypothesis on the CO2 electrochemical reduction on pyrite in modeling experiment, the installation was constructed which consisted of a fluorocarbon electrochemical cell with two separated electrode chambers installed into a high-pressure autoclave permitting a continuous CO2 flow (50 atm, 10 ml_min1) through cathode chamber. The cathode (7 cm2) was manufactured of a hydrothermal pyrite monocrystal and anode was a platinum plate. The cell's electrodes were connected with a programmed potentiostate and the recording unit. The cell was filled with 0.1 M KHCO3 electrolyte, and the CO2-saturated solution was subjected to electrolysis (24 hrs, room temperature).
Starting with a cathode potential about 800 mV (vs. saturated Ag|AgCl r.e.), the accumulation of formate in electrolyte was observed by a color reaction with chromotropic acid. No formate production was registered under normal atmospheric pressure and in the absence of imposed cathode potential. Neither in experiments, nor in control formaldehyde was found. The yield of formate demonstrated an exponential growth as a function of cathode potential value at least up to 1200 mV. The maximal faradaic efficiency of formate synthesis (0.12%) was observed at 1000 mV. The results point to geoelectrochemical systems capable to the CO2 cathode reduction as a novel source of abiogenic organics.