The genetic diversity and phylogeny of green microalgae in the genus Choricystis (Trebouxiophyceae,Chlorophyta) in Lake Baikal

Limnology - Green microalgae are of the utmost importance to aquatic ecosystems globally, as they are primary producers and major food sources for many organisms. Microalgae of the genus...     

Microorganisms in the Sediments of Lake Baikal,the Deepest and Oldest Lake in the World

Microbiology - The review summarizes the results of recent studies of microbial communities of the Lake Baikal sediments obtained using diverse techniques. In the sediments of the areas of stable...     

Molecular phylogenetic analysis of the ant genus <Emphasis Type="Italic">Formica</Emphasis> L. (Hymenoptera: Formicidae) from Palearctic region

Sixty-five sequences of the mitochondrial DNA cytochrome b gene fragment (759 bp) and 23 sequences of the NADH dehydrogenase subunit 6 gene fragment (224 bp) were compared in ants of the genus Formica L. from different regions of the Palearctic and in Polyergus rufescens Latr. as outgroup. In total, 28 species of the genus Formica were examined. As a result, dated trees with a molecular clock were constructed showing the phylogenetic relationships of Formica ants. The topology of the obtained tree based on the Cyt-b sequences was found to be not consistent with the generally accepted opinion on the Formica rufa and F. rufibarbis groups. New data on the formation history of the present-day fauna of Formica ants of the Palearctic were obtained. It was demonstrated that a considerable fraction of the examined species (about a third) were formed in the Quaternary Period.     

Substrate Specificity of Methanogenic Communities from Lake Baikal Bottom Sediments Associated with Hydrocarbon Gas Discharge

Methane production by microbial communities from Lake Baikal bottom sediments with different chemical composition of pore water was studied. Methane production was more active in the media supplemented with H₂: CO₂ and H₂ + CH₃COONa, rather than on media with acetate as the sole source of carbon and energy. Addition of methanol stimulated methane production only in the case of microbial communities from upper silts. Ability of the communities to produce methane correlated reliably with the concentrations of the NO^3–, SO₄^2?, Cl^–, and CH₃COO^– ions in the pore water of the relevant sediments. Cultivation of communities from the mud volcano sediments resulted in development of methanogenic archaea of the family Methanocellaсеае in the media supplemented with H₂: CO₂ and H₂ + CH₃COONa, while methanogenic archaea in the communities cultivated without additional substrates belonged to the genera Methanoregula, Methanobacterium, and Methanosaeta.     

Phylogenetic diversity of microbial communities of the Posolsk Bank bottom sediments,Lake Baikal

Massive parallel sequencing (the Roche 454 platform) of the 16S rRNA gene fragments was used to investigate microbial diversity in the sediments of the Posolsk Bank cold methane seep. Bacterial communities from all sediment horizons were found to contain members of the phyla Actinobacteria, Bacteroidetes, Deinococcus-Thermus, Firmicutes, Nitrospirae, Chloroflexi, Proteobacteria, and the candidate phyla Aminicenantes (OP8) and Atribacteria (OP9). Among Bacteria, members of the Chloroflexi and Proteobacteria were the most numerous (42 and 46%, respectively). Among archaea, the Thaumarchaeota predominated in the upper sediment layer (40.1%), while Bathyarchaeota (54.2%) and Euryarchaeota (95%) were predominant at 70 and 140 cm, respectively. Specific migration pathways of fluid flows circulating in the zone of gas hydrate stability (400 m) may be responsible for considerable numbers of the sequences of Chloroflexi, Acidobacteria, and the candidate phyla Aminicenantes and Atribacteria in the upper sediment layers and of the Deinococcus-Thermus phylum in deep bottom sediments.     

Experimental study of DNA hydratation

The present article as a review of experimental investigations of water-DNA interaction in solutions, films, fibres, and crystals. The discussion of the experimental data is directed to the analysis of the sizes of the hydration shells of the DNA atomic groups, the distances at which atomic groups of DNA affect the hydration of each other; the structural, thermodynamic and kinetic characteristics of the water in the DNA hydration shell and their relations with DNA structure. The modern views on the mechanisms by means of which the water affects the physico-chemical properties of DNA are discussed.     

Occurrence of markers, distribution of genotypes and risk factors for viral hepatitis C among some groups of the population in the Novosibirsk region

The occurrence of markers, genotypic variability of isolates and risk factors for viral hepatitis C (HCV) were studied in 4 groups of residents of the Novosibirsk region (altogether 2,000 persons). Anti-HCV IgG were detected within the range from 4.6% among medical personnel to 48% among the patients of the drug-abuse clinic. The detection rate of HCV RNA in seropositive samples varied from 79.3% to 86.3%. The determination of genotype was carried out for 388 isolates: 1b--50.3%, 2a--4.4%, 2c--0.3%, 3a--44.8%. The highest risk indices with respect to HCV among the residents of the region were linked with the drug use (OR=77.5; p<0.05) as well as with risky behavior and low social status. The elevated numbers of seropositive persons were detected among unemployed (OR=16.3), alcohol abusers (OR=3.9), persons having more than 4 sex partners in their lifetime (OR=4.3) and persons having homosexual contacts (OR=6.6). In some groups blood transfusions also played a definite role in the transmission of HCV. In the analysis, carried out separately for two different genotypes the intravenous use of drugs was perceptibly stronger linked with VHC of genotype 3 (OR=85.5) in comparison with HCV of genotype 1 (OR=49.3) and genotype 2 (OR=41.1). Genotype 1 prevailed in the older age group and genotype 3, among young people.     

The occurrence rate of HGV/GBV-C RNA and risk factors in patients of narcological dispensary in Novosibirsk

The occurrence rate of HGV/GBV-C RNA, genotypic variety of isolates and various risk factors of infection with HGV/GBV-C were evaluated in 500 patients of the narcological dispensary of Novosibirsk. The occurrence rate of HGV/GBV-C RNA among all examined blood sera was 33.6%. At the same time in blood sera with HCV markers the occurrence rate of HGV/ GBV-C was 42.9% and in sera with negative results for markers HCV--25%. For gene typing of obtained isolates the direct sequencing of the amplification products of fragment NS3B and the phylogenetic analysis of the sequences thus obtained were used. Almost all isolates subjected to gene typing belonged to genotype 2, widespread in Europe, and only 1 isolate was classified with genotype 4. Statistically significant (p<0.05) risk of HGV/GBV-C infection among the examined subjects was linked with the intravenous use of drugs (OR 2.15), risky sexual behavior (OR 1.8) and the presence of virus hepatitis C (OR 2.26).     

Effects of dantrolene and ryanodine on the evoked activity of neuromuscular synapses in mice

Ryanodine was shown to potentiate in a frequency-dependent manner a late phase of initial facilitation increasing the EPP amplitude for 15%-40% in a fixed interval 140-400 ms after the first EPP in the discharge. Dantrolene prevented the ryanodine induced increase of the late phase of facilitation, decreased 2-fold the amplitude and quantum content of single EPPs, augmented initial depression, blocked facilitation in 50% of synapses. Only in presence of dantrolene, the ryanodine's ability to increase the EPPs quantum content and early phase of the EPP facilitation in rhythmically active synapses, was revealed.