Bioastronomy 2007: Molecules, Microbes, and Extraterrestrial Life. ASP Conference Series, Vol. 420, 2009. K. J. Meech, J. V. Keane, M. J. Mumma, J. L. Siefert, ...
Bioastronomy 2007: Molecules, Microbes, and Extraterrestrial Life ASP Conference Series, Vol. 420, 2009 K. J. Meech, J. V. Keane, M. J. Mumma, J. L. Siefert, and D. J. Werthimer, eds.
Chromatic Complementary Adaptation (CCA) for the Exploration of Exoplanetary Life M. V. Tarasashvili and N. G. Alexidze Dept. of Biochemistry and Biotechnology, I. Javakhishvili Tbilisi State University, I Chavchavadze ave. 1. 0128. Tbilisi, Georgia Abstract. The purpose of our research is develop an astrobiological model of possible living processes on exoplanets. Imitations of exoplanetary systems have significant theoretical and practical value. Modeling in astrobiology involves: Selection of exoplanets suitable for the origin of life; Theoretical modeling of exoplanetary environment with polarization-holography methods; Imitation of stellar spectra and experiments with Chromatic Complementary Adaptation; Laboratory modeling of the ecosystem and alien life. The main problem is the integration of investigations both in astrophysics and biotechnology. We have showed for the first time the possibility and expediency of such approach, for the solution of astrobiological problems.
1.
Introduction
Research is based on the modeling of possible biochemical processes on exoplanets. Imitations of exoplanetary systems have significant theoretical and practical values. Modeling in astrobiology involves: 1) Selection of exoplanets suitable for the origin of life; 2) Theoretical modeling of exoplanetary environment with polarization-holography methods; 3) Imitation of stellar spectra; 4) Experiments with Chromatic Complementary Adaptation; 5) laboratory modeling of alien ecosystems and life. Theoretical discussions and results obtained from our experiments demonstrate that potentially inhabitant planetary bodies reveal unusual environmental conditions and provide unique evolutionary scenario and biodiversities. Modeling of star spectra, selection of adapter pigments and other lightharvesting complexes and synthesis of the artificial photosynthetic film, in future could provide oxygen supply for space stations, space ships, Lunar and Martian colonies. 2.
Strategy and Methods
First task was to identify exoplanets or their hypothetic satellites suitable for life. After analyzing astronomical parameters for 200 exoplanets and their parent stars, we have found at least of them suitable for life and to be possibly suitable. During these calculations we have determined limits of the ecospheres around each star processing data for L-luminosity, S-star classes and R-radiation parameters. Calculations were followed by the experiments. We have constructed an experimental chamber that allows us to simulate actual ecological and illumination characteristics of the selected exoplanetary body and conduct environmental 243
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modeling. For the illumination purposes, actual stellar spectra were analyzed and broken down into Gaussian components. Results were used for the selection of appropriate optical filters. In the experimental chamber, combinations of optical glass are located under the primary light-source that summarizes discrete spectra and give back actual emission spectra of the stars of selected classes, illuminating exoplanetary bodies. At the same time, the chamber is equipped with lx-meter for the measurement of the radiation intensity and thermometers for the measurement of temperature.The experimental Chamber has enabled us to create modeled environment that might present of selected exoplanets. Following parameters have been imitated, measured and investigated: 1) Star spectra and surface illumination conditions; 2) Mean daily temperature; 3) Rate and preferable type of photosynthesis; 4) Expected prevalent coloring of photosynthetic organisms; 5) Suitable combinations of pigments and light-harvesting systems; 6) Selection and adjustment mechanisms of various photosynthetic organisms to preferred spectral shifts within integral imitated spectra. Some of our important results are presented below. Star classes are sequenced in accordance to the order of our investigations: 2.1.
Life at A Class Stars
If radiation waves shorter than 400nm enter the planetary atmosphere, then organisms should develop increased numbers of carotene-like pigments. Artificial coating of leaves with carotene envelope or extracts, and solutions added to protozoa colonies, increase their resistance to UV-radiation from 280 to 400nm. Phodoxantin gave best results so far. 2.2.
Life at B Class Stars
Our experiments have revealed plants: Rosmarinus officinalis, Hyssopus officinalis, Tarragon, Foeniculum Vulgare and others containing aromatic hydrocarbons (benzo[a]anthracene, chrysene, fluoranthene, b-caryophyllene, citronellol and geraniol), bicyclic monoterpene derivatives (L-pinocamphene, isopinocamphone) in main bodies - leaves and stem - to be unusually highresistant against incoming radiation waves shorter then 280nm, including gamma and x-ray (short exposure). Thus, protection from UV and even gamma- and X-rays can be maintained with the increase vaporization of aromatic hydrocarbons (cystamine, benzol-derrivatives, ets). During our investigations, experimental plants were excreting clouds of various aromatic hydro-carbonaceous substances. Similar clouds and viscose colloidal yellowish polymer cover on plants are expected on planets at highradioactive stars. 2.3.
M Class Stars and Brown Dwarfs: Beware of IR Life(?)
Ontogenesis of living creatures is the resemblance of their evolutionary development. In this case, insect-eater carnivorous plants are of special interest. Life at warm and low-radioactive red and Infra-Red stars does not necessarily require development of the variety of photosynthetic pigments. Instead, heterotrophic competition takes place. Members of such ecosystems most likely tend to develop as consumers predator and parasites, grow larger and evolve faster. For example, carnivorous plants have evolved in warm, wet climate under the thick plant cover, where preferably Red and IR waves (and maybe UV waves, if they
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are not cut by the planetary atmosphere) reach the surface. Although these plants are still partially photosynthetic, heterotrophic nutrition and digestion is still preferred. These results are based on investigations of metabolic rates, occurring under the artificial illumination of M-class and Brown Dwarf stars. 2.4.
Life at K and G Class Stars
These stars are subjects of our future investigations - dependence of Chromatic Complementary Adaptation on Ecosystem parameters (temperature, radiation intensity, illumination, humidity, etc.) and its photochemical foundation is of interest. Initial results suggests that if an atmosphere (or other living matrix aerial or liquid) does not prevent the entrance of incoming radiation waves, then co-pigmentation and other biochemical adaptations take place in order to defend living organism for damaging extra-intensities. This is especially important for the inhabitants of such planets that the cross inner border of the ecosphere at periapsis. 3.
Conclusions
In order to keep focusing on CCA, this research highlights evolutionary aspects of optical adaptation in living systems. Chromatic Complementary Adaptation is the consequence of the adjustment of chromo-protein composition of photosynthetic light-harvesting antennae system. Changes in light properties and light-harvesting structures help the living organisms to maximize or minimize the absorption of prevalent wavelength of light in the environment and maintain sufficient rates of natural artificial photosynthesis as well as various ways of Carbon conversion. It is obvious that the variety of forms and coloring is expected at any inhabited body; however, the prevalence of green-colored plants on Earth was taken into consideration, accepted as objective fact and used as initial research point. Thus, we have concluded the following: 1. Life can occur at different stages of stellar and planetary evolution. Stars of O, B, A classes can have planets with life (consider evolution of stars in multiple systems). 2. Size and luminosity of stars varies, but if there are planets or their satellites within ecosphere limits, life can evolve. 3. Biodiversity is the result of combinations between the adaptations to ecosystems, circadian events and CCA phenomena. Still, variety (biodiversity) is dependant on high-quality life, entering planetary atmosphere. 4. Genetic regulation of CCA makes possible the creation of transgenic organisms adapted to various illumination conditions that can be used for the implementation of Terraformation (of the Moon and/or Mars). 5. CCA is an excellent tool for the prediction of some physical and biochemical properties of extraterrestrial life, but terrible and almost useless for the visual detection of life through the optical instruments, especially on those planetary bodies covered with atmosphere.
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It now remains to investigate the precise metabolic mechanisms involved in CCA and photosynthesis under the illumination of different stars. Using the phenomena of CCA, photochemical properties of pigments and research in photosynthesis, I. Javakhishvili Tbilisi State University, Biochemical Association of Georgia, together with the Institute of Cybernetics, are making efforts to synthesize bionic film-covers for alternative oxygen-supply of space stations. This method involves artificial initialization of the processes similar to bacterial adhesion in bio-films and synthesis of crystal-enriched glass for the energy transformations (UV and short-waved light are transformed into extra amount of Red and IR waves) and used in photosynthesis. Acknowledgments. We thank Abastumani Astrophysical Observatory staff for the stellar spectra and expert advice; Georgia Institute of Cybernetics for the supplement of Optical Devices; Prof Shalva Sabashvili and Prof. Elene Davitashvili for assistance. References Calvin, M. & Gazenko, O. 1975. Foundations in Space Biology and Medicine. Vol. 1 (pp. 217-316), Vol. 2 (pp 78-87); Vol. 3 (pp 318-324) M. Nauka & NASA STIO WD.C. Goodwin, T. W. 1965. Chemistry and Biochemistry of Plant pigments. Aberrwyth, Wales. Academic Press. NY. London. Pickelner S.B. 1976. Physics in Space (pp 66-67, 538-539, 559-564) SE. Moscow. White, D. 2000. The physiology and Biochemistry of prokaryotes. Indiana University, Oxford University Press, Second ed.
