|
Executive Summary: Groupement de Recherche
en Exobiologie
Director/Leader: François Raulin
GDR Exobio
GDR CNRS 1877, or Groupement de Recherche
en Exobiologie is a national federation of research
laboratories in Exo/Astrobiology, created by the National
Centre of Scientific Research (CNRS) in 1999 and renewed
in 2003. Its main goal is to promote, induce and coordinate
the development of Exo/astrobiology scientific programs
in France. It includes about 50 laboratories,and is
supported by the CNRS and CNES (the French Space Agency).
4 main research topics are addressed:
=> The ingredients of primitive life in their geological,
planetological and interstellar context
=> From the chemistry of the origins of life to the
emergence of life: structures and functions of biological
molecules
=> Terrestrial life as a reference: fossils, biomarkers,
extreme environments
=> Habitats and signatures of extraterrestrial life
GDR Exobio has a scientific Council consisting of 19
scientists from different fields, including astrophysics,
planetology, physics, chemistry, earth sciences, life
sciences, as well as philosophy and epistemology. The
GDR has been affiliated with the NAI since November
2001.
Main recent activities
During the period July 2002-June 2003,
the GDR Exobio, within the framework of its main 4 topics,
has been active in several directions directly connected
to NAI activities. Below are just a few examples of
these activities, with the corresponding references
given in the Reference list.
Several important results on Titan’s
organic chemistry (Raulin & Owen 2002) have been
obtained by joint studies involving GDR and other teams,
including the determination of optical properties of
Titan’s tholins (Ramirez et al., 2002) and the
potential presence of oxirane on Titan (Coll et al,
2003). Evidence that POM may be a precursor of formaldehyde
in comets has been obtained through laboratory experimental
data and modeling (Cottin et al, 2003). The development
of methodologies and instrumentation for in situ exobiologically
oriented analyses of Martian soil has been reported
by GDR & US teams (Buch et al., 2003; Cabane et
al, 2003).
The effects of solar radiation on amino
acids and their derivatives exposed in Earth orbit has
been examined (Barbier et al., 2002a,b; Boillot et al.,
2002). The effects of interstellar and atmospheric mechanisms
on the prebiotic synthesis have been studied (Meierhenrich
et al., 2002). The identification of stable, biogenic,
chiral aliphatic hydrocarbons by GCMS was demonstrated
by Meierhenrich et al. (2003). An experiment simulating
artificial meteorites showed that extraterrestrial sediments
can reach the Earth (Brack et al., 2002a,b). Evidence
for the fractionation of oxygen isotopes during entry
of artificial meteorites into the Earth's atmosphere
has been shown (Miller et al., 2002).
The environment of the early Earth as
the context for early life on Earth and as an analogue
for life on other planets has been the subject of a
number of publications (Westall et al., 2002; Westall
et al., 2003; Westall and Drake, 2003; Westall, 2003a,b,).
Modern and ancient biofilms from the Early Archaean
have been studied as analogues for potential extraterrestrial
biofilms (Westall and Walsh, 2003; Walsh and Westall,
2003; Toporski et al., 2003a,b). It has been shown that
previous investigations for microfossils and for a biogenic
carbon isotope signal in the Early Archaean, 3.7to 3.8
Ga rocks from Greenland did not take into account the
presence of modern contaminating microorganisms (Westall
and Folk, 2003). The evolutionary status of the earliest
microfossils from 3.3-3.5 Ga rocks from Barberton and
the Pilbara was examined by Westall (2003c) Stromatolitic
microfossils preserved by hematite in the 2 Ga Gunflint
Formation serve as an analogue for potential Martian
microfossils in the Meridiani Planum hematite deposit
(Allen et al., 2003).
The presence of various microbial eukaryotes
in deep-sea hydrothermal settings and the association
of potential biogenic signatures to sulfur-metabolizing
bacteria have been shown (López-García,
2003a, 2003b).
Our efforts were also devoted to investigate
one of the most important biological aspects of the
origins of life, that is the RNA world hypothesis (Meli
et al, J. Biol. Chem, 2002; 2003). On the orther hand,
we were able to show by Surface Enhanced Raman Spectroscopy
(SERS) the detection of subpicomolar amount of nucleic
acid components trapped on mineral surfaces (Elamri
et al, in press).
The search for indications of biological
activity on extrasolar planets is also an important
part of the studies which are carried out by the GDR
team which involve large-scale cooperation, especially
with other teams linked to the NAI (DesMarais et al,
2003).
Exobio'03 , the 3rd bi-annual National exo/astrobiology
summer school will take place in Corsica in September
2003. As for the 2 previous schools, it will be attended
by close to 100 participants coming from astronomy and
geophysics (60 persons) and from chemistry and biology.
The program of this year includes: chronology: comparison
of time scales in astronomy, geophysics, chemistry and
biology; impacts and Earth bio-geo evolution; Moon formation;
chemical and biological evolution; auto-organisation
and complexification; exoplanets; life on mars, Titan,
Europa; interstellar chemistry; LUCA; Artificial life.
References
Allen C.C., Westall F., Longazo T.G.,
Schelble R.T., Probst L.W. & Flood B.E. (2003).
Meridiani Planum Hematite Deposit and the search for
life on Mars: Preservation of microfossils and associated
evidence of life in terrestrial samples. Icarus, in
press.
Barbier B., Henin O., Boillot F., Chabin A., Chaput
D. & Brack A. (2002a). Exposure of amino acids and
derivatives in the Earth orbit. Planet. Space Sci.,
50, 353-359.
Barbier B., Boillot F., Chabin A., Buré C., Venet
M., Belsky A., Jacquet R., Bertrand M., Delmas A. &
Brack A. (2002b). The PERSEUS-Exobiology experiment
onboard MIR, in Exo/Astrobiology, Proceedings 2d European
Workshop on Exo/Astrobiology, Graz, ESA Special Publication
ESA SP-518, 109-112.
Boillot F., Chabin A., Buré C., Venet M., Belsky
A., Bertrand-Urbaniak M., Delmas A., Brack A. &
Barbier B. (2002). The Perseus exobiology mission on
MIR: behaviour of amino acids and peptides in Earth
orbit, Origins Life Evol. Biosphere, 32, 359-385.
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. &
Wäsch E. (2002a). Do meteoroids of sedimentary
origin survive terrestrial atmospheric entry? The ESA
artificial meteorite experiment STONE. Planet. Space
Science, 50, 763-772.
Brack A., Baglioni P., Demets R., Edwards H.G., Kurat
G., Miller M.F. & Pillinger C.T. ( 2002b). The artificial
Martian meteorite experiment Stone-1. in Exo/Astrobiology,
Proceedings Second European Workshop on Exo/Astrobiology,
Graz 2002, Ed. H. Lacoste, ESA Special Publication ESA
SP-518, 155-157.
Buch A., Sternberg R., Meunier D., Rodier C., Laurent
C., Raulin F. & Vidal-Madjar C. (2003). Solvent
extraction of organic molecules of exobiological interest
for in situ analysis of the Martian soil, J. Chromatogr.
A 999, 165-174.
Cabane M.., Coll P., Szopa C. Israël G., Raulin
F., Sternberg R., Mahaffy P., Person A., Rodier C. Navarro-Gonzalez
R., Harpold D. & Brinckerhoff W. (2003). Did life
exist on Mars? Search for organic and inorganic signatures,
one of the goals for SAM. Adv. Space Res. Accepted.
Coll P., Bernard J.-M., Navarro-Gonzalez R. and Raulin
F. (2003). Oxirane: an exotic oxygenated organic compound
on Titan ? Ap. J. . in press.
Cottin H., Bénilan Y., Gazeau M.-C. and F. Raulin
F. (2003). Origin of cometary extended sources from
degradation of refractory organics on grains: polyoxymethylene
as formaldehyde parent molecule. Icarus, in press.
DesMarais D., Harwitt M., Jucks K., Kasting J., Lin
D., Lunine J., Seager, S., Schneider J., Traub W., et
Woolf N., (2003). Remote Sensing of Planetary Properties
and Biosignatures, Astrobiology, in press.
Elamri, C., Baron, M-H., Maurel, M-C. (2003) Adenine
in mineral samples. Surface Enhanced Raman Spectroscopy
for picomolar detection. Spectrochemica Acta A in press.
López-García, P, Philippe H., Gail F.
& Moreira M. (2003a). Autochthonous eukaryotic diversity
in hydrothermal sediment and experimental micro-colonizers
at the Mid-Atlantic Ridge, Proc Natl Acad Sci USA, 100,
697-702.
López-García P., Duperron S., Philippot
P., Foriel J., Susini J. & Moreira M. (2003b). Bacterial
diversity in hydrothermal sediment and epsilon-proteobacterial
dominance in experimental micro-colonisers at the Mid-Atlantic
Ridge. Environ Microbiol. in press
Meierhenrich U.J., Muñoz Caro G.M., Schutte W.-A.,
Barbier B., Arcones Segovia A., Rosenbauer H., Thiemann
W.H.-P. & Brack A. (2002). The prebiotic synthesis
of amino acids - Interstellar versus atmospheric mechanisms.
in Exo/Astrobiology, Proceedings Second European Workshop
on Exo/Astrobiology, Graz 2002, ESA Special Publication
ESA SP-518, 25-30.
Meierhenrich U. J., Nguyen M. J., Barbier B., Brack
A. & Thiemann W. H. (2003). Gas chromatographic
separation of saturated aliphatic hydrocarbon enantiomers
on permethylated beta-cyclodextrin. Chirality 15, suppl
S13-16 .
Miller M.F., Franchi I.A., Thiemens M.H., Jackson T.L.,
Brack A., Kurat G. & Pillinger C.T. (2002). Mass-independent
fractionation of oxygen isotopes during thermal decomposition
of carbonates. PNAS 99, 10988-10993.
Meli M., Vergne J., Décout J.L. & Maurel
M-C. (2002). Adenine-Aptamer Complexes. J. Biol. Chem.
277, 3, 2104 -2111.
Meli M., Vergne J. & Maurel M-C. (2003). In vitro
Selection of Adenine-dependent Hairpin Ribozymes. J.
Biol. Chem. 278, 11, 9835-9842.
Munoz Caro G.M., Meierhenrich U.J., Schutte W.A., Barbier
B., Arcones Segovia A., Rosenbauer H., Thiemann W.H.-P.,
Brack A. & Greenberg J.M. (2002). Amino acids from
ultraviolet irradiation of interstellar ice analogues,
Nature, 416, 403-406.
Ramirez S.I., Coll P., Da Silva A., Navarro-Gonzalez
R., Lafait J. & Raulin F. (2002). Complex Refractive
Index of Titan's Aerosol Analogues in the 200?900 nm
domain, Icarus, 156(2), 515-530, 2002.
Raulin F. & Owen T. (2002). Organic chemistry and
exobiology on Titan, Space Sci. Rev. 104, 377-394.
Toporski J., Steele A., McKay D.S., Westall F. Avci,
R., Schweitzer M., Pincus S. & Garcia Parro V. (2003).
New strategies for life detection and their implication
for astrobiological research and Solar System exploration.
in Frontiers of Life, 12èmes Rencontres de Blois,
L.M. Celnikier, J. Trân Than Vân (Eds),
The Gioi, Paris, 267-271.
Toporski J., McKay D.S., Steele F. & Westall F.
(2003). Bacterial biofilms in astrobiology: the importance
of life detection. In Fossil and Recent Biofilms (ed.
W.E. Krumbein, T. Dornieden, and M. Volkmann), Kluwer,
Amsterdam, in press.
Walsh M.M. & Westall F. (2003). Archean biofilms
preserved in the 3.2-3.6 Ga Swaziland Supergroup, South
Africa. In Fossil and Recent Biofilms (ed. W.E. Krumbein,
T. Dornieden, and M. Volkmann), Kluwer, Amsterdam, in
press..
Westall F. (2003a). Precambrian Geology and Exobiology.
in The Precambrian Earth: tempos and events, P. Erikssen,
W. Altermann, D. Nelson, W. Mueller, O. Catuneanu (Eds.),
Elsevier, in press.
Westall F. (2003b). Le contexte géologique pour
l'origine de la vie et les signatures minérales
de la vie fossile. Dans (Eds) Gargaud, M.M. et al.,
Les traces du vivant. Presses universitaires Bordeaux,
in press.
Westall F. (2003c). Stephen Jay Gould, les procaryotes
et leur évolution dans le contexte géologique.
Paléovol, in press.
Westall F., Folk R.L. (2003). Exogenous carbonaceous
microstructures in Early Archaean cherts and BIFs from
the Isua greenstone belt: Implications for the search
for life in ancient rocks. Precambrian Research, in
press.
Westall F. & Drake F. (2003). Is life an unavoidable
planetary phenomenon given the right conditions, in
Earth System Analysis for sustainability, W.C. Clark,
P.J. Crutzen and H.-J Schellnhuber (Eds.), Dahlem Konferenzen,
Berlin, in press.
Westall F. & Walsh M.M. (2003). Fossil biofilms
and the search for life on Mars. In Fossil and Recent
Biofilms (ed. W.E. Krumbein, T. Dornieden, and M. Volkmann),
Kluwer, Amsterdam, in press.
Future Hopes
The GDR wishes to participate in cooperative
programs of research, on clearly identified topics,
in the framework of its affiliation to NAI. The NAI
connection should be a great opportunity to share and
exchange researchers, in particular PhD students, to
promote joint participation in research programs on
Exo/astrobiology, and to use the synergy induced by
the different ways of thinking and working of researchers
from different origins to promote the wide field of
Exo/astrobiology. Targets such as Titan, in relation
to Cassini-Huygens, Mars and its international program
of exploration, Europa and Extrasolar planets are already
among the topics of high interest likely to be part
of such joint research projects. In addition, the need
for networking, with new and efficient tools for teleconferencing
(including asynchronous communication) remains a technical
priorities.
PREPARED BY
François Raulin, Director French GDR Exobio,
affiliated to NAI
Click here
to return to the main page. |
