[Functional features of microbial communities in the digestive tract of field voles (Microtus rossiaemeridionalis and clethrionomys glareolus)].

The nitrogen-fixating and cellobiohydrolase activity, the nitrogen (N) and carbon (C) contents, and the number of microorganisms in the prestomach, cecum, and colon of two vole species were studied: the southern vole (Microtus rossiaemeridionalis) and the bank vole (Clethrionomys glareolus), which is characterized by a mixed type of diet. The nitrogen-fixating activity in the cecum was found to be the highest in the voles compared with the mammals studied earlier. The seasonal dynamics of both nitrogenase and cellobiohydrolase activities was registered in the southern vole. The structure of the microbial complex in the southern vole is more varied and includes microorganisms associated with plant substrates.

[Microbiological characteristic of anthills of Lasius niger].

The characteristics of microbial communities of the anthills of Lasius niger compared to the soil beyond the area of the strong effect of ants is given.

[Specific features of nitrogen fixation in the termite Reticulitermes lucifugus].

Nitrogenase activity, abundance of diazotrophic bacteria, and structural and functional parameters have been determined in microbial complexes of three populations of the termite Reticulitermes lucifugus and their nest materials. These data have been used for comparative analysis of nitrogen-fixing micioorganism communities in termite guts and in nest materials from different termite populations. Similarities in the structure and other parameters of these communities have been revealed. The taxonomic composition of microbial communities differs among the populations, but the functional properties of these communities are almost identical. It is concluded that no symbiotic (mutualistic) relationship exists between nitrogen-fixing intestinal bacteria and their host termites.

[Methodological aspects of assessing chitin utilization by soil microorganisms].

A computational method for estimating specific activity of chitin decomposition by microorganisms is proposed. Spectrophotometric and gas chromatographic methods have been used to determine the rates of chitinase production, biomass accumulation, and carbon dioxide emission by pure cultures of microorganisms grown on a chitin-containing medium. Among dominants of the chitinolytic community of chernozem (Trichoderma viride, Stretomyces albolongus, Alcaligenes, and Arthrobacter), the highest chitinolytic activity is characteristic of prokaryotes. In brown desert-steppe soil, the main destructor prokaryotes are actinomycetes (S. roseolilacinus). The biomass of the fungus T. viride growth on the chitin-containing medium markedly exceeds that of prokaryotes, but the specific activity of respiration and chitinase production in actinomycetes S. roseolilacinus and S. albolongus is an order of magnitude higher than in T. viride.

[Vertical structure of bacterial communities in peats of the Yakhroma River floodplain].

The abundance and taxonomic structure of soil bacterial communities have been studied in different geomorphological parts of the Yakhroma floodplain. It has been found that the numbers of bacteria reach a peak in calcareous peat soil under forest near the floodplain terrace, decreasing to a minimum in soddy alluvial soil near the riverbed. All soils are characterized by the presence of different ecological-trophic bacterial groups capable of peat destruction. Seasonal dynamics of the structure of bacterial communities and, in some soil types, its spatial dynamics accounted for by changes in the botanical structure of peat across its profile have been revealed. All peat soils in the floodplain have high contents of organic matter and neutral pH and, therefore, are favorable biotopes for the development of saprotrophic bacteria. This, in turn, largely accounts for high productivity and stability of this agroecosystem as a whole.

[The saprotrophic bacterial complex in the raised peat bogs of Western Siberia].

The population density of bacteria in peat deposits along the landscape profile of the Vasyugan Marsh has been found to be as high as tens of millions of CFU/g peat. The abundance and diversity of bacteria increased with depth within the peat deposit, correlating with an increasing level of peat degradation. Variations in these parameters with depth and season were greater in peat deposits located in transaccumulative and transitional positions than in the sedge-sphagnum bogs located at the eluvial region of the profile. In the upper 1-m-thick layer of the peat deposits studied, bacilli, represented by five species, dominated, whereas, in the deeper layers, spirilla and myxobacteria prevailed. These bacteria were major degraders of plant polymers. Unlike the bacterial communities found in the peat deposits of European Russia, the dominant taxa in the studied peat deposits of Western Siberia are represented by bacteria resistant to extreme conditions.

[The ability of saprotrophic bacteria isolated from natural habitats to lyse yeasts]. / Drozhzheliticheskie svoistva saprotrofnykh bakterii iz prirodnykh mestoobitanii.

More than 600 bacterial strains isolated from different horizons of steppe biogeocenoses and zoogenous loci (diplopod intestines and feces) were tested for the ability to lyse yeast cell walls. About half of the strains that were isolated from biotopes with active degradation of plant debris (steppe litters and diplopod intestines and feces) were found to possess yeast-lytic activity. Most of the yeast-lytic strains belonged to the genera Streptomyces, Promicromonospora, Oerskovia, and Agromyces. The yeast-lytic activity of actinobacteria from the genera Agromyces, Mycobacterium, and Micrococcus has not previously been reported.

[Microbial complexes from apogeotropic roots and from rhizosphere of cycad plants]. / Struktura mikrobnykh kompleksov apogeotropnykh kornei i prikornevoi zony sagovnikovykh rastenii.

The microbial complexes of soil, the rhizosphere, and the rhizoplane of the apogeotropic (coralloid) roots of cycad plants were comparatively studied. The aseptically prepared homogenates of the surface-sterilized coralloid roots did not contain bacterial microsymbiont, indicating that it was absent in the root tissues. At the same time, associated bacteria belonging to different taxonomic groups were detected in increasing amounts in the cycad rhizoplane, rhizosphere, and the surrounding soil. The bacterial communities found in the cycad rhizoplane and the surrounding soil were dominated by bacteria from the genus Bacillus. The saprotrophic bacteria and fungi colonizing the cycad rhizosphere and rhizoplane were dominated by microorganisms capable of degrading the plant cell walls. The local degradation of the cell wall was actually observed on the micrographs of the thin sections of cycad roots in the form of channels, through which symbiotic cyanobacterial filaments can penetrate into the cortical parenchyma.

[Characteristics of nitrogen fixation and denitrification in Termites Neotermes castaneus, Zootermopsis angusticollis, and Reticulitermes lucifugus]. / Osobennosti azotofiksatsii i denitrifikatsii u termitov Neotermes castaneus, Zootermopsis angusticollis i Reticulitermes lucifugus.

We studied specific features of microbial nitrogen fixation and denitrification in laboratory cultures of the termites Neotermes castaneus, Zootermopsis angusticollis, and Reticulitermes lucifugus, as well as in their nest materials. The nitrogenase activity in the termites was much higher than in the materials of termitarium. Denitrification was found only in the nest materials of termitarium. Studies of the bacterial community of gut nitrogen fixers Neotermes castaneus have shown the predominance of anaerobic and facultatively anaerobic bacteria that amount to up to 60% of the total number of "gut" bacteria. In the materials of termitarium, aerobic cellulose-destroying myxobacteria predominated, which are typical inhabitants of plant substrates, a food for the termite.

[Bacterial soil variety: evaluation of methods, possibilities, and prospects ]. / Bakterial'noe raznoobrazie pochv: otsenka metodov, vozmozhnostei, perspektiv.

The paper presents a comparative description of the modern molecular genetic and routine culture techniques for assessing microbial diversity in soils and gives analysis for the different results obtained by these two groups of methods. The necessity of the collaboration of soil scientists, microbiologists, and molecular biologists in integrating different research methods for a proper assessment of soil microbial diversity is discussed. The paramount importance of soil as the source and reserve of biodiversity on the Earth is emphasized.

[Structure of bacterial complexes of the river Protva flood-plains]. / Struktura bakterial'nykh kompleksov poimennykh landshaftov reki Protvy.

The synecological analysis of bacterial communities from the Protva River flood-plain biogeocenosis showed that all of the horizons contain spirilla, which are typical hydrobionts, and pigmented coryneform bacteria associated with the herbaceous plants of the flood-plain meadows. The alluvial meadow soils of the inundated regions of the floodplain differed from the unflooded regions of the flood-plain in that they had a more diverse bacterial population continuously distributed over the soil profile.

[Bacterial diversity in microcosms of soils with various humidity]. / Otsenka bakterial'nogo raznoobraziia v pochvennykh mikrokosmakh pri raznoi vlazhnosti.

The succession analysis of bacterial diversity in the A horizons (rich in organic matter) of three contrasting types of soil--burozem, soddy gley soil, and chernozem--showed that the bacterial diversity of soil microcosms in humid regions can be adequately evaluated only if soil samples are incubated at different soil moisture contents. A complete account of actinobacteria and proteobacteria requires the levels of soil moisture corresponding to the maximum capillary-sorption moisture and capillary moisture, respectively. The bacterial diversity, whose value was maximum on the 40th day of succession, was higher in soddy gley soil than in burozem. The taxonomic structures of the bacterial communities of these two types of soil were different. After wetting chernozem samples from arid regions, the soil bacterial community changed insignificantly with time and drastically differed from that of soils from humid regions. The difference in the bacterial diversity of soils was the most distinct when it was evaluated by measuring the proportion between proteobacteria and actino-bacteria.

[Structure and function of microbial communities in soil from the southern Taiga]. / Struktura i funktsii mikrobnykh soobshchestv pochv iuzhnoi taigi.

General regularities in the structure of the microbial communities of southern taiga soil ecosystems and taxonomic differences between the microbial communities of soils with different hydrothermal characteristics are discussed with reference to the main types of soils of the Central State Forest Biosphere Reserve.

[Taxonomy of denitrifying bacteria in soddy podzolic soil]. / Taksonomicheskii sostav denitrifitsiruiushchikh bakterii v dernovo-podzolistoi pochve.

The taxonomic composition of denitrifying bacteria in soddy podzolic soil was studied by the succession analysis method. This method revealed a significant variation in the taxonomic composition of denitrifying microorganisms in the course of succession. In contrast to succession analysis, the single microbiological analysis of soil samples reflected only the late stage of succession and thus led to an underestimation of the major members of succession. Myxobacteria were found to be the most active denitrifiers at the early stages of succession, whereas bacilli dominated at its late stages. The bacilli were represented by three facultatively anaerobic species, Bacillus cereus, Bac. circulans, and Bac. polymyxa.

[Taxonomic position of the genus Mycococcus]. / O taksonomicheskom polozhenii roda Mycococcus.

An attempt to elucidate the taxonomic position of the genera Mycococcus has been made. For this purpose the full range of the taxonomically important properties were investigated among microbial cultures preliminary identified as Mycococci. As a result of comparison Mycococcus with Micrococcus the taxonomic status of the genus Mycococcus was no longer confirmed. On the grounds of the published data and the author's experimental results it was concluded that genus Micrococcus was closely related to genus Arthrobacter. The possibility to place the genus Micrococcus within the group of coryneform bacteria is being discussed.

[Spectrophotometric characteristics of the coccoid forms of actinomycetes]. / Spektrofotometricheskie kharakteristiki kokkovykh form aktinomitsetov

IR spectra of thw whole cells of the coccoid forms (Mycococcus and Micrococcus) isolated from lithophilous lichen were compared with IR spectra of the collection cultures of Micrococcus and Arthrobacter. Generic spectral characteristics of Mycococcus and Micrococcus are presented. Spectral heterogeneity within the genus Arthrobacter complicates the diagnosis. The cultures of the Mycococcus genus were divided into three groups according to their spectral characteristics. Spectral scans of the studied coccoid forms differ from the scans of the mycelial actinomycetes, and their intensities within the range of 900-1200 cm-1 (lipids) decrease in the series Mycococcus, Arthrobacter, Micrococcus.