Modern
investigations favor now 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 molecules could be
safely transported to Earth vicinity being associated with mineral grains.
Experimental studies of the possible ways and mechanisms of biologically
important substances (BIS) synthesis under the action of cosmic energy
sources is closely connected with investigating of the principles of
prebiotic evolution both on primitive Earth and on other planetary bodies
in Solar System. It is important to test whether organics synthesized in
Earth orbit could be protected by extraterrestrial mineral. Our
experiments onboard MIR space station were performed in terms of common
exobiological project “Perseus” which lasted from April 16 till August
7, 1999 (temperature range from –50C to +410C,
wave length from 120 to 225 nm). After retrieval, HPLC analysis is used to
identify synthesis products.
Dry
films containing aminoacids Gly+Trp, Trp and nucleoside+phosphate were
exposed on the surface of MIR orbital station displayed in experimental
hardware mounted on the core module. Similar films were irradiated by
vacuum ultraviolet (145 nm) and ultraviolet (245 nm) light in the parallel
laboratory experiments. Following peptides were identified as the reaction
products: Gly-Gly, Trp-Gly, Gly-Trp, Trp-Trp (in case of Gly+Trp mixture)
and Trp-Trp, Trp-Trp-Trp (for Trp only). The phosphorylation of adenosine,
uridine and thymidine has been also studied in this context. Formation of
5’-mononucleotides seemed to be the most effective reaction both in
flight and in laboratory experiments. The presence of lunar soil both in
flight and in ground experiments increases the reaction yield roughly in 2
times. To identify and evaluate the principal source of energy in open
space responsible for peptides and nucleotides synthesis reaction
laboratory experiments were performed. It has been shown, that in open
space conditions as well as in ground experiments peptides and nucleotides
synthesis takes place. The presence of Lunar soil increases reaction
yields in 1.5 - 2.0 times.
Presumably
these results favour the protective role of mineral bed from the
destructive impact of cosmic radiation at the organic molecules
synthesized in space conditions. In course of our experiments it was
clearly demonstrated, that the formation of more complicated organic
molecules, as compared to the initial ones, takes place in open space
conditions whereas the prevailing formation of natural peptides and
nucleotides has been shown for each experimental mixture. These
experiments make important contribution to the problem of life origin and
prove the possibility of organic substances formation in space conditions.
