Izvestiia Akademii nauk. Seriia biologicheskaia最新文献

Analysis of the sequence ITS1-5.8S-ITS2 in 11 samples of the amaranth species (Amaranthus caudatus, A. cruentus, A. hybridus, A. tricolor, A. paniculatus, A. hypohondriacus) was performed. It has been shown that the variability of the sequences of the intergenic spacers ITS1, ITS2 and 5.8S rRNA gene of the amaranth species analyzed is extremely low. A possible secondary structure of the 5.8S rRNA molecule was determined for the first time; three conservative motifs were identified. A single nucleotide substitution found in A. hybridus did not change the loop topology. In the sample of Celosia cristata taken as an external group, a four-nucleotide insertion in the 5'-end of the gene and a one-nucleotide deletion in the fourth hairpin not affecting the general topology of the 5.8S rRNA molecule were found.

The genetic diversity of the Uralian moose population and the role of the Ural region in the phylogeographic structure of the European moose were evaluated based on sequence polymorphisms of the mtDNA control region. The nucleotide diversity of the Ural moose was low, whereas haplotype diversity was rather high. It was found that the haplotype pool of the Ural moose reflects both the unique features of their mitochondrial lineages and their connection with Alces alces alces populations of Europe and West Siberia. The structure of median networks and the territorial haplotype distribution support the hypothesis that the mitochondrial lineages typical for this part of the European moose area originate from a late Pleistocene refugium that was located in the Urals.

Synthetic glucocorticoid dexamethasone decreased locomotor activity of neonatal rats 120 h after administration. Behavioral changes were associated with an increase in the content of active caspase-3 in the cerebellum. We found that expression of this apoptotic protease was similar to the control value when dexamethasone action was combined to hypoxic treatment to rats; however, the locomotor activity decreased to the hormone action did not recovered. We found that proapoptotic action of dexamethasone was blocked by hypoxic treatment; however, it was not sufficient for prevention of the effect of hormone on behavior.

Succession on five fallows of Tuva has been studied. It has been shown that the fallow succession proceeds regularly and synchronously. Under the arid conditions of Tuva, weeds are developed at the initial stage of the succession (0-4 years). The first intermediate stage (4-7 years) on all fallows is characterized by the absolute predominance of weeds and the appearance of dominants typical for specific steppes. At the second intermediate stage (7-11 years), the species of aboriginal steppes dominate on all fallows. At the late stage (11-17 years), terminal communities with the combinations of species typical for each steppe, including predominant species, are developed.

The level of heterogeneity and genetic variability of cells in a suspension of Arabidopsis thaliana cultured in vitro for more than seven years was studied. The considerable heterogeneity of the suspension in cell size was shown. As revealed by nuclear DNA cytophotometry, the suspension culture was mixoploid and the amount of DNA in the cells varied from 4 to 16 C. However, PCR with 6 RAPD- and 4 ISSR-primers and their intra-group combinations showed the lowest degree of variability of DNA markers. The genetic distances of clones obtained from a suspension culture of the parent plant were only 1.5%. Differences between the clones were identified with only one pair of 31 primer combinations tested, indicating low level of genetic heterogeneity of the suspension. The results showed that variations in the amount of DNA in the suspension culture cells are not accompanied by significant changes in the DNA sequence.

This study determined the characteristic features of microbial communities inhabiting frozen soils of Central Sakha. All groups of microorganisms were present in high numbers comparable with the microbial densities in steppe soils of Transbaikalia; their distribution along soil profiles followed a specific pattern with no decrease in abundance with depth. In summer, the dominant groups of the microbial pool were actinomycetes and oligonitrophilic bacteria, while in autumn it was heterotrophic bacteria. A typical feature of the frozen soils of Central Sakha was the gradual penetration of microorganisms into deeper soil horizons during the vegetation season and their accumulation in the suprapermafrost horizon by autumn.

The influence of explant type as well as of the type of growth regulators and concentration on callus induction processes and somatic organogenesis of shoots was studied in vitro on four tomato genotypes of Russian breeding. Cytological study of callus tissue was conducted. It was established that tomato varieties possess a substantially greater ability to indirect shoot organogenesis compared with the F1 hybrid. The highest frequency of somatic organogenesis of shoots, as well as their number per explant, was observed for most of the genotypes studied during the cultivation of cotyledons on Murashige-Skoog culture medium containing 2 mg/l of zeatin in combination with 0.1 mg/l of 3-indoleacetic acid. An effective protocol of indirect somatic organogenesis of shoots from different explants of tomato varieties with a frequency of more than 80% was developed.

The results of interspecific crosses of the social vole Microtus socialis with the Altai vole M. obscurus, the East European vole M. rossiaemeridionalis, and the Transcaspian vole M. transcaspicus are presented. The role of the sperm head structure in the reproductive isolation of this species was studied. Hybrids were obtained in five of the six crossing combinations. It is established that significant differences in the sperm head shape in the social vole and in arvalis group species do not prevent fertilization. The sterility of hybrids indicates the existence of postcopulative mechanisms of reproductive isolation.

A comparative study of the effect of tissue and suspension allografts of an embryonic spinal cord on regeneration of nerve fibers of impaired (by application of a ligature) sciatic nerve in rats was conducted. It was demonstrated that unlike tissue grafts that reach a large volume 21 and 60 days after transplantation, suspension grafts do not inhibit the growth of axons of the recipient to the periphery. It was established that introduction of a suspension of dissociated cells of the spinal cord embryonic anlages (but not fragments of these anlages) into the impaired sciatic nerve in rats results in an increase in the amount of myelinated regenerating nerve fibers of the recipient 60 days after the operation.

The effect of immobilization of nitrile-utilizing bacteria Rhodococcus ruber gt1 and Pseudomonasfluorescens C2 by adhesion on carbon supports on the content of the intracellular ATP immediately after adsorption and after 2 h and 24-48 h after transfer of the adhered cells into a fresh nutrient medium was studied. Adhesion was shown to lead to a decreased concentration ofATP in a cell by one order of magnitude or more in the first hours in a fresh nutrient medium that'can be attributed to energetic consumption upon the initiation of biofilm formation. A gradual rise in the quantity of ATP, which was calculated per 1 mg of adsorbed cells, was reported to take place in daily and two-daily biofilms, which confirms the cells remain viable.