M. Yu. Trusova

Phylogenetic diversity of winter bacterioplankton of eutrophic siberian reservoirs as revealed by 16S rRNA gene sequence.

Using 16S rRNA gene sequence analyses we investigated the bacterial diversity of winter bacterioplankton of two eutrophic Siberian reservoirs. These reservoirs show similarity in phytoplankton community composition in spring and autumn but tend to differ in summer in exhibiting cyanobacterial bloom. Forty-eight unique partial 16S RNA gene sequences retrieved from two libraries were mostly affiliated with the class Actinobacteria, b subdivision of the class Proteobacteria, and the phylum Cytophaga–Flavobacterium–Bacteroides. The clone library of the pond exhibiting summer cyanobacterial bloom showed more diversity in sequence composition. A significant number of bacterial 16S rRNA gene clones were closely related to freshwater bacteria previously found in different aquatic ecosystems. This finding confirms the assumption that some bacterial clades are globally distributed.

Microbial community of the chemocline of the meromictic Lake Shunet (Khakassia, Russia) during summer stratification.

The spatio-temporal organization of the bacterial community inhabiting the chemocline of the stratified meromictic Lake Shunet (Khakassia, Russia) was investigated from May to September 2005 by means of microscopy, analysis of photosynthetic pigments, and PCR-DGGE with subsequent 16S rDNA analysis. The samples were collected with a multisyringe stratification sampler, sampling being performed every 5 cm. It was demonstrated that, during the period of investigation, there were no large changes in the bacterial community of the chlemocline, at least among the detected forms. During the whole period of study, purple sulfur bacteria related to Lamprocystis purpurea (Chromatiaceae) were predominant in the chemocline. Beneath the layer of purple bacteria, green sulfur bacteria were revealed that were phylogenetically distant from strain ShNPel02, which was previously isolated from this lake. Development of phytoflagellates of the genus Cryptomonas was observed in the upper zone of the chemocline. In the chemocline of Lake Shunet, the numbers of picoplankton cyanobacteria of the genus Synechococcus increased from May to September. It was demonstrated that the application of universal bacterial primers for DGGE resulted in the same qualitative distributional pattern of predominant species as microscopic studies.

Degradation of polyhydroxyalkanoates and the composition of microbial destructors under natural conditions

The degradation dynamics of polyhydroxyalkanoates of different composition has been studied in an eutrophic storage reservoir for two seasons. It has been shown that the biodegradation of polymers under natural conditions depends not only on their structure and physicochemical properties but also, to a great extent, on a complex of weather-climatic conditions affecting the state of the reservoir ecosystem. The molecular genetic analysis of 16S rRNA has revealed bacterial species (clones) probably involved in the degradation of polyhydroxyalkanoates in a model storage reservoir.

Species-specific stimulation of cyanobacteria by silver carp Hypophthalmichthys molitrix (Val.).

ISSN 0012-4966, Doklady Biological Sciences, 2006, Vol. 408, pp. 223–225.

[Physiological and biochemical characteristics and capacity for polyhydroxyalkanoates synthesis in a glucose-utilizing strain of hydrogen-oxidizing bacteria, Ralstonia eutropha B8562].

The physiological, biochemical, genetic, and cultural characteristics of the glucose-utilizing mutant strain Ralstonia eutropha B8562 were investigated in comparison with the parent strain R. eutropha B5786. The morphological, cultural, and biochemical characteristics of strain R. eutropha B8562 were similar to those of strain R. eutropha B5786. Genetic analysis revealed differences between the 16S rRNA gene sequences of these strains. The growth characteristics of the mutant using glucose as the sole carbon and energy source were comparable with those of the parent strain grown on fructose. Strain B8562 was characterized by high yields of polyhydroxyalkanoate (PHA) from different carbon sources (CO2, fructose, and glucose). In batch culture with glucose under nitrogen limitation, PHA accumulation reached 90% of dry weight. In PHA, β-hydroxybutyrate was predominant (over 99 mol %); β-hydroxyvalerate (0.25–0.72 mol %) and β-hydroxyhexanoate (0.008–1.5 mol %) were present as minor components. The strain has prospects as a PHA producer on glucose-containing media.

Degradation of Bioplastics in Natural Environment

Manufacturing indestructible synthetic plastics has reached 140 million tons for year, and accumulation of them in natural environment poses a global ecological problem [1]. For this reason, the design and development of biodegradable plastics that enter biospherical cycles is consistent with the concept of ecologically safe sustainable industrial development. Polyhydroxyalkanoates (PHA)—biodegradable and thermoplastic polymers that are close in their physicochemical properties to polypropylene and polyethylene—have been intensively studied today [2, 3]. Various bacteria classified with widespread soil and aquatic microorganisms (genera Pseudomonas, Alcaligenes, Comamonas , and Streptomyces ) are effective destructors of PHAa [4].

Microbial Communities and Transformation of Carbon Compounds in Bog Soils of the Taiga Zone (Tomsk Oblast)

Two types of bogs were studied in Tomsk oblast—Maloe Zhukovskoe (an eutrophic peat low-moor bog) and Ozernoe (an oligotrophic peat high-moor bog). The gram-negative forms of Proteobacteria were found to be dominant and amounted to more than 40% of the total population of the microorganisms investigated. In the peat bogs, the population and diversity of the hydrolytic microbial complex, especially of the number of micromycetes, were lower than those in the mineral soils. The changes in the quantitative indices of the total microbiological activity of the bogs were established. The microbial biomass and the intensity of its respiration differed and were also related to the depth of the sampling. In the Zhukovskoe peat low-moor bog, the maximal biomass of heterotrophic microorganisms (154 μg of C/g of peat) was found in the aerobic zone at a depth of 0 to 10 cm. In the Ozernoe bog, the maximal biomass was determined in the zone of anaerobiosis at a depth of 300 cm (1947 μ g of C/g of peat). The molecular-genetic method was used for the determination of the spectrum of the methanogens. Seven unidentified dominant forms were revealed. The species diversity of the methanogens was higher in the oligotrophic high-moor bog than in the eutrophic low-moor bog.

Differences in carbon isotope signatures of polyunsaturated fatty acids of two microalgal species

183 The study of fluxes of organic carbon in the bio sphere is one of the most relevant problems of modern ecology [1]. The paths of carbon in food webs in natu ral ecosystems are tracked by various methods based on the use of biochemical markers and stable isotopes as well as their combination, namely, the compound specific isotopic analysis (CSIA) that are biomarkers [2, 3]. However, the use of isotopic analysis of the key Differences in Carbon Isotope Signatures of Polyunsaturated Fatty Acids of Two Microalgal Species E. S. Kravchuka, N. N. Sushchika, O. N. Makhutovaa, M. Yu. Trusovaa, G. S. Kalachevaa, and M. I. Gladysheva, b Presented by Academician I.I. Gitel’zon June 2, 2014

Component elements of the carbon cycle in the middle and lower Yenisei River

An integrated study of the middle and lower Yenisei River was performed in the summer of 2012. It involved monitoring the key elements and ecological processes associated with the carbon cycle of the river ecosystem (the study area is more than 1800 km long). Measurements of the production and destruction processes have shown the failure of the “neutral pipe” hypothesis claiming that any river is a simple drain of carbon from terrestrial ecosystems to the ocean. The Yenisei River is not a purely heterotrophic ecosystem. It also has autotrophic areas, where the primary production of planktonic photosynthesis is higher than respiration (above the Angara River and near the Bolshaya and Malaya Heta rivers). According to the data, the respiration rate of the plankton community in the river depends mostly on the water temperature and the content of inorganic phosphorous that can restrict the amount of organic matter consumed by bacterioplankton.

Uptake of amino acids by uncultivated bacterioplankton of a eutrophic water reservoir

Water bacterioplankton species (clones) feeding on lysine and glycine were revealed in experimental microecosystems using nonsterile cultivation. The structure of the community was analyzed by separation of amplified fragments of the bacterial 16S rRNA gene of by denaturing gradient gel electrophoresis. The dominant species (clones) of the bacterioplankton were identified by molecular cloning and determining the nucleotide sequence of part of the 16S gene of ribosomal RNA. It was found that glycine, one of the prevalent amino acids of a eutrophic reservoir, and lysine, whose content in natural water is lower, are nutrient substrates for various subdominant bacterioplankton species (clones). Thus, free-living bacterial species are highly specialized for the uptake of individual amino acids.