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At least 19 recordsLinked to original sources
PubMedDate not supplied

[Weltanschauung aspects of the problem of man, the biosphere and space].

The paper discusses philosophic approaches to the problem of man-environment interplay. Many important problems humanity faces today are associated with biology. Biomedical and astrophysical studies are being carried out to gain a better insight into the laws governing evolution and further development of the Universe. The emergence of a human society started a qualitatively new stage in the evolution of organic matter. A rapid progress of science and engineering is accompanied by a significant rearrangement of the natural environment and, particularly, of living beings. The biosphere is transforming into the sphere of intelligence, i.e. noosphere. However, natural phenomena are still more powerful than man-made productive forces. Man's excursion into outer space allowed him to look at himself as if from the outside and to evaluate critically his actual role, position and responsibility in the infinite Universe as compared with other forms of life and intelligence. The Universe may be boundlessly great but for human beings there is nothing better than the Earth. Our planet will long remain the base for the existence and development of humanity. Today man ought to take the streering-wheel of evolution and fate of the biosphere into his hands, in order to preserve, through the efforts of many generations, our planet as the gem of the Universe.

Biological Evolution↗
PubMedDate not supplied

[Possibility of using higher plants in a life-support system on the moon].

The paper discusses the possibility of repeated termination of plant vegetation by prolonged darkness approximating the lunar night. This may be helpful for the incorporation of higher plants into the life support system of lunar bases, the solar light being used for illumination. In this connection vegetables (beet Bordeaux, turnip Petrovskaya, carrot Chantanet, dill, radish Virovsky white) and wheat (variety Sonora) were cultivated during the lunar light-dark cycle (i. e. 15 day light: 15 day dark). The experiments demonstrated that traditional plant products can be obtained under the conditions of lunar photoperiod. Grain of wheat grown during the lunar photoperiod were tested as seed material for further cultivation under similar conditions.

Ecological Systems, Closed↗
PubMed1979

The analysis of water in the Martian regolith.

One of the scientific objectives of the Viking Mission to Mars was to accomplish an analysis of water in the Martian regolith. The analytical scheme originally envisioned was severely compromised in the latter stages of the Lander instrument package design. Nevertheless, a crude soil water analysis was accomplished. Samples from each of the two widely separated sites yielded roughly 1 to 3% water by weight when heated successively to several temperatures up to 500 degrees C. A significant portion of this water was released in the 200 degrees to 350 degrees C interval indicating the presence of mineral hydrates of relatively low thermal stability, a finding in keeping with the low temperatures generally prevailing on Mars. The presence of a duricrust at one of the Lander sites is taken as possible evidence for the presence of hygroscopic minerals on Mars. The demonstrated presence of atmospheric water vapor and thermodynamic calculations lead to the belief that adsorbed water could provide a relatively favorable environment for endolithic organisms on Mars similar to types recently discovered in the dry antarctic deserts.

Extraterrestrial Environment↗
PubMedDate not supplied

Soil and water and its relationship to the origin of life.

Soils of the terrestrial planets form at the boundaries between lithosphere, atmosphere and hydrosphere. Biogenesis occurred in these zones; thus, it is axiomatic that some, perhaps many, stages of biogensis occurred in intimate association with the mineral constituents of soils. Because of a high surface to mass ration and, consequently, a high surface reactivity, the layer lattice clay minerals are the most important of these. According to the geological record, clay minerals appeared very early on the primordial Earth. Recent investigations have confirmed their presence in carbonaceous meteorites and have indicated their occurrence on Mars. In this paper we collect pertinent physico-chemical data and summarize the organic reactions and interactions that are induced or catalyzed by clays. Many clay-organic reactions that do not occur readily at high water contents proceed rapidly at adsorbed water contents corresponding to surface coverages of one or two molecular layers. One or two monolayers of adsorbed water correspond to extremely dry or cold planetary environments. Some consequences of these facts vis á vis biogenesis on Mars are considered.

Adsorption↗
PubMedDate not supplied

[Xerophytic microorganisms multiplying under conditions close to Martian ones].

The xerophytic cultures Bacillus megaterium and Mycococcus ruber can grow in the imitated Martian conditions. Therefore, they are resistant to the extreme factors of the environment: the composition of atmosphere, low pressure, the maximum hygroscopicity of a substrate, periodic freezing-thawing.

Bacillus megaterium↗
PubMed1978

Response of terrestrial microorganisms to a simulated Martian environment.

Soil samples from Cape Canaveral were subjected to a simulated Martian environment and assayed periodically over 45 days to determine the effect of various environmental parameters on bacterial populations. The simulated environment was based on the most recent available data, prior to the Viking spacecraft, describing Martian conditions and consisted of a pressure of 7 millibars, an atmosphere of 99.9% CO2 and 0.1% O2, a freeze-thaw cycle of -65 degrees C for 16 h and 24 degrees C for 8 h, and variable moisture and nutrients. Reduced pressure had a significant effect, reducing growth under these conditions. Slight variations in gaseous composition of the simulated atmosphere had negligible effect on growth. The freeze-thaw cycle did not inhibit growth but did result in a slower rate of decline after growth had occurred. Dry samples exhibited no change during the 45-day experiment, indicating that the simulated Martian environment was not toxic to bacterial populations. Psychotrophic organisms responded more favorably to this environment than mesophiles, although both types exhibited increases of approximately 3 logs in 7 to 14 days when moisture and nutrients were available.

Atmosphere↗
PubMed1977

Dry-heat resistance of selected psychrophiles.

The dry-heat resistance characteristics of spores of psychrophilic organisms isolated from soil samples from the Viking spacecraft assembly areas at Cape Kennedy Space Flight Center, Cape Canaveral, Fla., were studied. Spore suspensions were produced, and dry-heat D values were determined for the microorganisms that demonstrated growth or survival under a simulated Martian environment. The dry-heat tests were carried out by using the planchet-boat-hot plate system at 110 and 125 degrees C with an ambient relative humidity of 50% at 22 degrees C. The spores evaluated had a relatively low resistance to dry heat. D(110 degrees C) values ranged from 7.5 to 122 min, whereas the D(123 degrees C) values ranged from less than 1.0 to 9.8 min.

Bacillus subtilis↗
PubMed1976

Pulmonary function evaluation during the Skylab and Apollo-Soyuz missions.

Previous experience during Apollo postflight exercise testing indicated no major changes in pulmonary function. Pulmonary function has been studied in detail following exposure to hypoxic and hyperoxic normal gravity environments, but no previous study has reported on men exposed to an environment that was both normoxic at 258 torr total pressure and at null gravity as encountered in Skylab. Forced vital capacity (FVC) was measured during the preflight and postflight periods of the Skylab 2 mission. Inflight measurements of vital capacity (VC) were obtained during the last 2 weeks of the second manned mission (Skylab 3). More detailed pulmonary function screening was accomplished during the Skylab 4 mission. The primary measurements made during Skylab 4 testing included residual volume determination (RV), closing volume (CV), VC, FVC and its derivatives. In addition, VC was measured in flight at regular intervals during the Skylab 4 mission. Vital capacity was decreased slightly (-10%) in flight in all Skylab 4 crewmen. No major preflight-to-postflight changes were observed. The Apollo-Soyuz Test Project (ASTP) crewmen were studied using equipment and procedures similar to those employed during Skylab 4. Postflight evaluation of the ASTP crewmen was complicated by their inadvertent exposure to nitrogen tetroxide gas fumes upon reentry.

Aerospace Medicine↗
PubMedDate not supplied

Photochemical synthesis of simple organic free radicals on simulated planteary surfaces-an ESR study.

Electron spin resonance spectroscopy provided evidence for formation of hydroxyl radicals during ultraviolet photolysis (254 nm) at -170C of H2O adsorbed on silica gel or of silica gel alone. The carboxyl radical was observed when CO or CO2 or a mixture of CO and CO2 absorbed on silica gel at -170C was irradiated. The ESR signals of these radicals slowly disappeared when the irradiated samples were warmed to room temperature. However, re-irradiation of CO or CO2, or the mixture CO and CO2 on silica gel at room temperature then produced a new species, the carbon dioxide anion radical, which slowly decayed and which was identical with that produced by direct photolysis of formic acid adsorbed on silica gel. The primary photochemical process may involve formation of hydrogen and hydroxyl radicals by means of (1) photodissociation of H2O physically adsorbed on the silica gel, or (2) absorption of the excitation energy by the silica gel surface with subsequent cleavage of the silanol bonds, or (3) dissociation of H2O molecules throug photosensitization by the surfaces or a combination of (1) to (3). Subsequent reactions of these radicals with adsorbed CO or CO2 or both yield carboxyl radicals, CO2H, the precsursors of formic acid. Our results confirm the formation of formic acid under simulated Martian conditions and provide a mechanistic basis for gauging the potential importance of gas-solid photochemistry for chemical evolution on other extraterrestrial bodies, on the primitive earth and on dust grains in the interstellar medium.

Adsorption↗
PubMed1976

General constraints on the Viking biology investigation.

The Viking biological investigation will be conducted in the face of a number of constraints. Problems are created because of the inherent engineering of the instrument, communication constraints and other factors.

Astronomical Phenomena↗
PubMed1976

Acid-labile amino acid precursors in the Murchison meteorite. 1: Chromatographic fractionation.

The amino acid content of a hot water extract of the Murchison meteorite can be increased by over 100 per cent by subjecting the extract to acid hydrolysis. The acid-labile compounds in the extract that account for this increase were fractionated by column chromatography on a cation exchange resin. Seventy mole per cent behaved as neutral or acidic compounds and were eluted from the column with an initial water wash. The remaining 30 mole per cent (basic precursors) were retained on the column and were eluted with the free amino acids by aqueous NH4OH. The acid-labile amino acid precursors in the water eluate could be retained and further fractionated on an anion exchange column, indicating that they are acidic compounds.

Acids↗
PubMed1976

Acid-labile amino acid precursors in the Murchison meteorite. II: A search for peptides and amino acyl amides.

The basic fraction of the acid-labile amino acid precursors found in hot water extracts of the Murchison meteorite was treated with ninhydrin under conditions that give destruction of free amino acids but allow nearly complete recovery to peptides and amino acylamides. After this treatment and a subsequent acid hydrolysis, the amount of amino acids found corresponded to less than 30 per cent of the precursor content of the basic fraction. Since only 30 percent of the total extract precursors are found in the basic fraction, these results indicate that such compounds, if present, account for no more than 9 mole per cent of the total acid-labile amino acid precursors of the meteorite hot water extract.

Amides↗
PubMed1975

Life and chirality beyond the earth.

An attempt is made to show that the phenomenon of chirality- of which optical activity is but one consequence- is by no means restricted to life on Earth, but is common throughout the universe. Several independent sources have been investigated including: statistical fluctuations; stereoselective physical factors; and energetic differences between enantiomeric molecules. It is emphasised that a search for chirality as an indicator for life elsewhere in space provides an excellent tool for the fascinating question of exobiology. Still one must be aware of the limitations of the experimental methods and their interpretations.

Extraterrestrial Environment↗