Amphibia as a Vector of Transfer of Long-Chain Polyunsaturated Omega-3 Fatty Acids from Aquatic to Terrestrial Ecosystems.

The flow of long-chain polyunsaturated fatty acids (PUFAs) of the omega-3 family, namely, eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA), exported by amphibian metamorphs from water to terrestrial ecosystems in the Medveditsa River floodplain, was quantified for the first time. The total biomass export by three amphibian species (Pelobates fuscus, Bombina bombina, and Pelophylax ridibundus) per unit area of the lake surface was 0.594 g/m2 per year (as a mean for 2 years). The biomass flow per unit area of land was 0.726 g/ha per year (0.302 g/ha per year for organic carbon) in 2015-2016. The average annual total removal of EPA + DHA by amphibians from the floodplain lake was 1.47 mg/m2 of water surface area. Due to the high content of EPA and DHA in biomass, amphibians are potentially a valuable food for terrestrial predators having no access to other sources of essential PUFAs.

Analysis of fatty acid composition revealed differences in the diets of tadpoles of two amphibian species.

The study of the composition of fatty acid markers of tadpoles of cohabiting amphibian species for the first time revealed differences in their diets: the moor frog Rana arvalis prefers bacteria not associated with plant detritus, whereas the diet of the common spadefoot Pelobates fuscus is based on cyanobacteria, green algae, diatoms, and possibly higher plants. Major differences in the fatty acid composition are determined by the difference in the percentage of eicosapentaenoic and myristic acids.

Development of human exometabolite deep mineralization method for closed ecosystems.

Methods of physicochemical further oxidation of hardly soluble sediment obtained from "wet combustion" of human exometabolites applied to space-purpose Bio Technological Life Support Systems (BTLLS) were studied. Most hardly dissoluble sediment containing Ca, P, Mg, and other essential plant nutrition elements were shown to dissolve in H2O2 and HNO3 aqueous media activated by alternating electric current. Dissolved additional mineral elements allowed (as demonstrated for lettuce) to increase the productivity of BTLLS phototrophic unit plants more than twice, which is comparable to their productivity on standard Knop solution with balanced chemical composition. Thus, dissolved mineral elements can be involved into BTLLS turnover process and increase its closure degree.

[Synthesis of 3-hydroxybutyrate-CO-4-hydroxybutyrate copolymers by hydrogen-oxidizing bacteria].

Synthesis of 3- and 4-hydroxybutyrate copolymer (3HB-CO-4HB), the most promising member of the biodegradable polyhydroxyalcanoate (PHA) family, has been studied. Cultivation conditions of naturally occurring strains of hydrogen-oxidizing bacteria Ralstonia eutropha B5786 and Cupriavidus eutrophus B10646 have been optimized to ensure efficient synthesis of the 3HB-CO-4HB copolymer. A set of highly pure samples of the 3HB-CO-4HB copolymer with 4HB content varying from 8.7 to 24.3 mol % has been obtained. Incorporation of 4-HB into the copolymer was shown to cause a more pronounced decrease in polymer crystallinity than the incorporation of 3-hydroxyvalerate or 3-hydroxyhexanoate; samples with a degree of crystallinity below 30% have been obtained. The weight average molecular mass of the 3HB-CO-4HB copolymers was shown to be independent on the monomer ratio and to vary broadly (from 540 to 1110 kDa).

[Microbial polymers as a degradable carrier for pesticide delivery].

The possibility of use of polyhydroxyalkanoates (PHAs), biodegradable microbial polyesters, as a carrier for pesticides (alpha-hexachlorocyclohexane and lindane) for targeted and controlled delivery of these compounds to soil was investigated. The kinetics of polymer degradation and the dynamics of pesticide release from the extended-release formulations was studied. It is shown that pesticides embedded in a degradable polymer (PHA) carrier are released gradually and slowly, without surges, as the polymer is degraded by the soil microflora. The microbial soil component actively responded to the addition of the polymer as an additional nutrient substrate: the latter was degraded and then utilized. The rate of the pesticide release to the soil can be regulated by varying the polymer-pesticide ratio.

Distribution and resorption of polymeric microparticles in visceral organs of laboratory animals after intravenous injection.

Microparticles obtained by using (14)C-labeled resorbable hydroxyaminobutyric acid polymer were injected into the caudal vein of laboratory animals without negative aftereffects for their growth and development and without changes in the macro- and microstructure of organs and tissues. The distribution of microparticles in the viscera and the dynamics of accumulation of carbon-containing polymer degradation products in the viscera were studied. The main targets for the particles are liver tissues, as well as renal and splenic tissues. The polymeric matrix of the microparticles is most actively destroyed in the spleen and liver. The presence of high-molecular-weight polymeric matrix in organs indicates the integrity of microparticles and the possibility of long-term (up to 12 weeks) functioning of polymeric particles in vivo.

[Synthesis of reserve polyhydroxyalkanoates by luminescent bacteria].

The ability of marine luminescent bacteria to synthesize polyesters of hydroxycarboxylic acids (polyhydroxyalkanoates, PHA) as reserve macromolecules was studied. Twenty strains from the collection of the luminescent bacteria CCIBSO (WDSM839) of the Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, assigned to different taxa (Photobacterium leiognathi, Ph. phosphoreum, Vibrio harveyi, and V. fischeri) were analyzed. The most productive strains were identified, and the conditions ensuring high polymer yields in batch culture (40-70% of the cell dry mass weight) were determined. The capacity of synthesizing two- and three-component polymers containing hydroxybutyric acid as the main monomer and hydroxyvaleric and hydroxyhexanoic acids was revealed in Ph. leiognathi and V. harveyi strains. The results allow luminescent microorganisms to be regarded as new producers of multicomponent polyhydroxyalkanoates.

[Fatty acid composition of Wautersia eutropha lipids under conditions of active polyhydroxyalkanoates synthesis].

The fatty acid composition of the lipids of a Wautersia eutropha polyhydroxyalkanoate-producing strain was studied by chromato-mass spectrometry. A total of 27 fatty acids were identified; their distribution in the cell fractions was determined. In the cytoplasmic membrane, palmitic, palmitoleic, and cis-vaccenic acids were the major components. Long-chain beta-hydroxy acids and myristic acid (components of the lipopolysaccharides of the cell envelope) predominated in the fraction of strongly bound lipids. When the polymer was actively synthesized, the content of cyclopropane acids in the easily extracted lipids increased and the content of the corresponding monoenoic acids decreased. The strongly bound lipids had a high content of long-chain beta-hydroxy acids (more than 50% of the total fatty acids). These results made it possible to determine the source of polyhydroxyalkanoate (PHA) contamination and to choose the strategy for their purification.