[Astrobiological investigations on board Russian space crafts].

The possibility of prebiotic synthesis of nucleic acids components (nucleotides) has been demonstrated under condition of the space orbital stations and satellites under effect of all space radiation spectra. Since a lot of different nucleic acids components are known to be present within small space bodies, we have to investigate their chemical complication in respect with such components as nucleotides. The goal of this work is to review our results in the field of prebiotic synthesis of purine and pyrimidine nucleotides on the board of Russian space crafts. The increase in the solid reaction mixtures exposure time leads to degradation of both initial components (nucleosides) and the reaction products (nucleotides). The dominating role of heat energy in the abiogenic reactions has been revealed in laboratory (ground) experiments. Similar set of natural nucleotides has been synthesized under effect of different open space energy sources in both flight and ground experiments. The formation of 5'-nucleotides is a dominating process. All the data are discussed in the context of exobiological investigations on the Earth's orbit.

Prebiotic synthesis of nucleotides at the Earth orbit in presence of Lunar soil.

Modern studies now favor the fact that extraterrestrial organic molecules served as an important source of biological important substances on the primitive Earth. It is presumed that these space-made organic molecules could be transported safely to the Earth surface being associated with mineral grains. It is important to test whether nucleotides synthesized in Earth orbit could be protected by lunar surface regolite. The phosphorylation of adenosine, uridine and thymidine has been studied with respect of their further transformations and degradation in presence of mineral bed. After retrieval, HPLC analysis is used to identify all the mononucleotides of certain nucleosides. It has been shown, that exposure of the investigated nucleosides as dry films in space conditions in the presence of Lunar soil increases the yield of synthesized nucleotides in 1.1-3.0 times as compared with the exposure of the same samples in absence of Lunar soil. To identify and evaluate the principal source of energy in open space responsible for nucleotide synthesis reaction laboratory experiments were performed. It has been shown, that vacuum ultra violet (VUV 145 nm) radiation promotes nucleotide synthesis more effectively than ultra violet (UV 254 nm) while the presence of Lunar soil increases reaction yield in 1.5-2.0 times. Formation of 5'-mononucleotides seemed to be the most effective reaction both in flight and in laboratory experiments. Protective action of lunar soil on synthesized nucleotides against UV radiation has been shown in open Space conditions.

Study of the peptide prebiotic synthesis in context of exobiological investigations on earth orbit.

Dry films of amino acids mixtures glycine+ tryptophan and tryptophan were exposed on the surface of "Mir" station. Similar films were irradiated by vacuum ultra violet (145 nm) and ultra violet (254 nm) in the laboratory experiments. Gly-Gly, Trp-Gly, Gly-Trp, Tpr-Trp and Trp-Trp-Trp were the main reaction products for the experimental mixture glycine + tryptophan and Tpr-Trp and Trp-Trp-Trp for tryptophan. The presence of Lunar soil both in flight and in laboratory experiments increases the reaction yield by 1.5-2.0 times. Therefore, the hypothesis concerning the possibility of safe delivery of peptides and amino acids required for the emergence of life and associated with mineral have got yet another approval.

Abiogenic synthesis of pyrimidine nucleotides in solid state by vacuum ultraviolet radiation.

The abiogenic synthesis of pyrimidine nucleotides in solid state has been investigated. Our experiment indicates that natural nucleotides are produced in thin films prepared from nucleoside and inorganic phosphate by irradiating with vacuum ultraviolet light (VUV, lambda=100-200 nm). We have investigated the influence of the type of nucleic acids base (thymidine, cytosine, uracil) and the structure of sugar moiety (ribose or deoxyribose) on the course and yield of reaction. We compared the action of vacuum ultraviolet light with action of gamma-radiation, heat and biology significant UV (254 nm) which have been investigated earlier. The occurrence of these reaction in open space is discussed.

Formation of oligopeptides on the surface of small bodies in solar system by cosmic radiation.

The present experiment indicates that oligopeptides are easily produced in solid state from mixtures of simple amino acids by irradiating with high energy charged particles. We investigated such amino acids and their mixtures as tryptophan, tyrosine and glycine. The thin films was irradiated with protons (6.6 MeV). Such dipeptides as Trp-Trp, Gly-Tyr, Tyr-Gly, and Tyr-Tyr have been detected as products of irradiation. Cosmic rays might be an effective energy source for abiotic formation of bioorganic compounds on the surface of small bodies in the solar system on early stage of formation of planets as well as at present day.

[The role of ultraviolet and gamma radiation in the abiogenic synthesis of nucleotides in the solid state]. / Rol' UF- i gamma-radiatsii v abiogennom sinteze nukleotidov v tverdom sostoianii.

A possibility of abiogenic synthesis of natural nucleotides in solid state under the influence of UV and gamma radiation has been shown for a mixture of nucleosides and dihydrophosphate. Adenosine and deoxyadenosine were used as initial substances. During adenosine and deoxyadenosine phosphorylation under the action of UV radiation (lambda = 254 nm), only 5'-monophosphates were formed, a yield of 0.094 and 0.36% respectively. Under the action of gamma radiation, 2',3'-cAMP (0.12%), 2'-AMP (0.08%) and 3'-AMP (0.14%) were produced together with 5'AMP (0.41%).

[Effect of individual factors of the space environment on the abiogenic synthesis of nucleotides]. / Vliianie otdel'nykh faktorov kosmicheskoi sredy na abiogennyi sintez nukleotidov.

Key role of thermal energy has been shown in abiogenic synthesis of natural nucleotides (deoxyadenosine and cytidine monophosphates) in a solid phase during phosphorylation of deoxyadenosine and cytidine at the board of the orbital station "Salute-7" (temperature from -50 to 65 degrees C, exposition for 13 months) and in laboratory experiments (temperature 65 degrees C, exposition from 8 days to 6 1/2 months). The results obtained are discussed in relation to possible contribution of thermal energy in processes of prebiological evolution on the lithosphere of the Primitive Earth and various cosmic bodies.

[Photochemical transformations of nucleic acid components in the presence of lunar soil]. / Fotokhimicheskie prevrashcheniia komponentov nukleinovykh kislot v prisutstvii lunnogo grunta.

It has been demonstrated that lunar soil is an effective catalyzer of photolysis of thin-solid films of uracil and uridine. Uracil photolysis proceeds more intensively both in the presence of the lunar soil and in absence of the latter as compared to the photolysis of uridine. Together with photodestruction of uracil, the extension in the initial molecular structure takes place.

[Effect of salts and sole of metal oxides on radiochemical changes in carbohydrates and abiogenic amino acid synthesis]. / Vliianie solei i zolei okislov metallov na radiatsionno-khimicheskie izmeneniia uglevodov i abiogennyi sintez aminokislot.

It has been shown that gamma-irradiation of solutions of carbohydrates in the presence of sulfates and metal oxide sols results in oxidative and destructive processes and leads to formation of carbonile compounds, organic acids, H2CO, and a substance with lambda max= =261 nm. With respect to their catalytic effect on carbohydrate changes, the sulfates and metal oxide sols investigated may be arranged into the following order: CuSO4 > > MnSO4=NiSO4 > ZnSO4 > H2O (salt free glucose solution); MoO3 > V2O5 > Al2O3 > > H2O (glucose solution without metal oxide sol). Radiolysis of glucose, mannose and arabinose is affected by the nature of gas saturating the solutions: O2 > Ar > CO2. Ionizing irradiation of solutions of hexoses and pentoses which contain nitrates as the source of nitrogen, results in the formation of amino acids with the chain length from 2 to 6 atoms of carbon (gly, ser, lys, ala, asp, his, tre, val, glu).

[Abiogenic nucleoside synthesis in the presence of phosphorus salts]. / Abiogennyi sintez nukleozidov v prisutstvii fosfornykh solei.

By means of UV-spectroscopy, gel-filtration, ion-exchange and thin layer chromatography it has been shown that the action of ionizing radiation on the mixture of dry preparations of adenine and deoxyribose in the presence of the K, Na and Ca phosphates results in the formation of nucleoside-like substances. The phosphates catalyze or inhibit the nucleoside synthesis but they are not phosphorylating agents. The data obtained indicate the reality of abiogenic synthesis of nucleoside-like substances from the mixture of dry preparations of adenine and deoxyribose in the lithosphere during chemical evolution.

[Synthesis of purine and pyrimidine nucleosides under the action of high temperature and UV-radiation]. / Sintez purinovykh i pirimidinouykh nukleozidov pod vliianiem vysokoi temperatury i ul'trafietovoi radiatsii

By means of UV-spectroscopy, gel filtration, thin layer and paper chromatography, it has been shown that the action of UV irradiation and heat on a dry mixture of nitrogenous bases and deoxyribose results in the formation of nucleoside pool, particulary deoxyadenosine. These energy sources were chosen in order to imitate at least approximately the conditions assumed to exist on the primitive Earth. Similar synthesis takes place in the atmosphere of the three gases studied, being more intensive in CO2 than in N2 or O2.