[Methods of extending the resource of fiber ionite artificial soils in space greenhouses].

The vegetable cultivation technology developed in view of long-term autonomous missions is based on root nutrition provided by fiber artificial soils (AS) containing ion-exchange resins. Useful life of ASs is limited by two factors which are nutrients depletion in ion-exchanger and clogging of the AS threshold space by roots remnants. Purpose of the investigation is to try out hydrolysis and ensuing microbial decomposition of roots remnants as a way to extend the resource of used fiber ionite AS. This principle of doing away with the roots remnants recovers almost completely the maximal water-absorbing capacity of AS BIONA-V3 so that it can be used again for crops cultivation.

[Novel halotolerant bacterium from cryopeg in permafrost: description of Psychrobacter muriicola sp. nov].

A novel halotolerant psychrotrophic gram-negative bacterium, strain 2pS, was isolated from lenses of water brine in Arctic permafrost (cryopeg). The optimal growth of the new strain was observed at 16-18 degrees C; the maximal and minimal growth temperatures were 37 degrees C and -2 degrees C, respectively. The pH growth range was 5.8 to 8.5 (optimum 6.5-7.5) and the range of medium salinity was 0 to 100 g/l (optimum 3-8 g/l NaCl). The strain 2pS did not produce acid from carbohydrates and utilized acetate, yeast extract, pyruvate, glutarate, fumarate, caproate, heptanoate, butyrate, malate, DL-lactate, citrate, L-proline, L-tyrosine, butanol, and dulcitol as the sole carbon and energy sources. The major fatty acids of the cell wall at optimal growth temperature were C18:1(omega 7) and C18:1(omega 9). The G + C DNA content was 46.0 mol.%. Phylogenetic analysis of the 16S rRNA gene sequences showed that the studied strain was the closest (97% similarity) to Psychrobacter nivimaris DSM 16093T, a halotolerant psychrotrophic bacterium isolated from the Arctic sea's ice. Genotypic and phenotypic differences of the new bacterium from closely related species lead to the conclusion that strain 2pS belongs to a novel species of the genus Psychrobacter: Psychrobacter muriicola sp. nov.

[Interrelation between the pathways of isoprenoid biosynthesis and carbon source catabolism in anaerobic and facultatively anaerobic bacteria].

Data on the interrelation between the pathways of the carbon source catabolism and isoprenoid biosynthesis in anaerobic and facultatively anaerobic bacteria were obtained. Two pathways of isoprenoid biosynthesis (nonmevalonate and mevalonate) were revealed in the representatives of the genus Clostridium. The non-mevalonate pathway of isoprenoid biosynthesis and the glycolytic pathway of substrate oxidation are typical of glucose-grown bacteria, whereas the pentose phosphate cycle operates in xylose-grown bacteria. The mevalonate pathway of isoprenoid biosynthesis was revealed in strain Clostridium thermosaccharolyticum DSM 571 grown in the presence of mevinolin, as well as in a number of lactic acid bacteria. Mevinolin is known to react with the lactate dehydrogenase complex, preventing reduction of pyruvate. The nonmevalonate pathway of isoprenoid biosynthesis was revealed in Bifidobacterium bifidum. The role of different metabolic pathways in isoprenoid biosynthesis is discussed.

[Prevalence of nonmevalonate and mevalonate pathways for isoprenoid biosynthesis among bacteria of different systematic groups].

The effect of fosmidomycin and mevinoline, inhibitors of the nonmevalonate and the mevalonate pathway of isoprenoid biosynthesis, respectively, on the growth of 34 anaerobic and 10 aerobic prokaryotic strains was studied. Fosmidomycin at the concentrations used was shown to inhibit the growth of 9 (of 10) representatives of the family Microbacteriaceae, 4 (of 5) strains of Thermoanaerobacter, and 11 (of 12) strains of Clostridium, whereas mevinoline inhibited the growth of lactobacilli (Carnobacterium), methanogenic and sulfate-reducing bacteria insensitive to fosmidomycin. During the late growth phase, four strains of actinobacteria (of nine) accumulate the compound, which, upon oxidation, generates a long-lived free radical; three strains synthesize 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (MEC). It was concluded that the difference in the sensitivity of the organisms to fosmidomycin and mevinoline might serve as a test to differentiate several representatives of the family Microbacteriaceae. The use of mevinoline for inhibiting methanogens in ecological investigations seems to be promising.

[Investigation of the process of personal hygiene items biodegradation by cellulose-fermenting microorganisms]. / Issledovanie protsessa biodegradatsii sredstv lichnoi gigieny mikroogranizmami-tseliulolitikami.

Cellulose-containing wastes are one of the heaviest and biggest ingredients of solid domestic wastes piling up during spaceflight. For the most part these are disposable personal hygiene items used in large quantities in the absence of shower. These wastes contain human body products which are very dangerous from the sanitary-epidemiological standpoint. The purpose was to explore potentiality of microbial biodegradation of cellulose-containing hygiene items anaerobically with dry mass transformation into liquid and biogas. Among specific objectives were test cultivation of active strains of reference cultures of cellulose-fermenting anaerobic thermophilic bacteria on hygiene items as the only source of carbon, evaluation of ways and need of pretreatment of gauze pads to stimulate biodegradation, and chemical analysis of resulting biogas. From the investigation it was concluded that gauze pads are susceptible to biodegradation by anaerobic bacteria producing a low toxicity gas fraction. Therefore, the proposed technology can be considered as a candidate for integration into the spacecrew life support system.

[Analysis of the anaerobic microbial community capable of degrading p-toluene sulphonate]. / Analiz anaérobnogo soobshchestva mikroorganizmov, razrushaiushchego n-toluolsul'fonat.

Three strains of Clostridium sp., 14 (VKM B-2201), 42 (VKM B-2202), and 21 (VKM B-2279), two methanogens, Methanobacterium formicicum MH (VKM B-2198) and Methanosarcina mazei MM (VKM B-2199), and one sulfate-reducing bacterium, Desulfovibrio sp. SR1 (VKM B-2200), were isolated in pure cultures from an anaerobic microbial community capable of degrading p-toluene sulfonate. Strain 14 was able to degrade p-toluene sulfonate in the presence of yeast extract and bactotryptone and, like strain 42, to utilize p-toluene sulfonate as the sole sulfur source with the production of toluene. p-Toluene sulfonate stimulated the growth of Ms. mazei MM on acetate. The sulfate-reducing strain Desulfovibrio sp. SR1 utilized p-toluene sulfonate as an electron acceptor. The putative scheme of p-toluene sulfonate degradation by the anaerobic microbial community is discussed.

[Clostridium thermocellum--a new object of genetic studies]. / Clostridium thermocellum--novyi ob''ekt geneticheskikh issledovanii.

A pronounced cellulolytic activity of the anaerobic thermophilic bacterium Clostridium thermocellum makes it a promising object for biotechnology, which requires elaboration of the methods for genetic analysis of this microorganism. At the first stage of the studies aimed at development of methods of the genetic material transfer to Clostridium thermocellum we elaborated a procedure for producing and regenerating protoplasts with the efficiency of up to 1%. The protoplast transformation was performed by the DNA of shuttle vectors pHV33 (KmRTcRApR) and pMK419 (CmRApR) constructed in this work. Modifications of the previously described methods of plasmid DNA isolation were developed. The cryptic 25 kb and 45-50 kb plasmids were detected in the strains F1 and F7 and isolated.

[Minimal synthetic nutrient medium for Clostridium stricklandii bacteria]. / Minimal'naia sinteticheskaia pitatel'naia sreda dlia bakterii Clostridium stricklandii.

A composition of minimal culture medium for the anaerobic bacterium Clostridium sticklandii strain CSG was determined. A fully synthetic culture medium promoting the cell yield up to 1 g dry biomass per 1 1 was found. It is composed of 13 amino acids, sodium formiate, four vitamins, microelements and salts. The strain under study does not utilize glucose as a carbon and energy source.

[Synthetic medium for culturing Clostridium sporogenes]. / Sinteticheskaia sreda dlia kul'tivirovaniia Clostridium sporogenes.

Clostridium sporogenes was shown to be capable of good stable-growth and biomass accumulation up to 5 mg/ml (dry weight) in a chemically defined medium. Along with glucose, the culture required the following amino acids for its growth: arginine, phenylalanine, glycine tyrosine, leucine, isoleucine, valine, tryptophan, and methionine. The culture could grow in the absence of inorganic nitrogen but required such elements as phosphorus, iron and magnesium. Addition of cysteine to the medium accelerated the growth and increased the biomass yield. Leucine at a concentration over 0.1% inhibited the growth. Two vitamins, viz. biotin and p-aminobenzoic acid, are sufficient for the growth of the culture.