Changes in the antigenic phenotype of mouse thymocytes after exposure to chemical inducers of differentiation and ionizing radiation

Irradiation of a mouse thymocyte fraction enriched by T-lymphocyte precursors changes the antigenic phenotype of cells toward the increase of their highly differentiated forms. Similar changes in membrane marker antigens are produced by chemical inductors of differentiation and thymotropin. The changes in the cell phenotype induced by the above agents are associated with both membrane and intragenome rearrangements. The results of the experiments on preventing the expression of some antigens by puromycin and the data on the level of spontaneous genome lesions in thymocyte fractions have prompted an assumption that destabilization of the genome upon irradiation increases DNA injury above some critical level which may serve a stimulus for "sorting out" the most radiosensitive thymocyte fraction.     

Sequence divergence of the mitochondrial DNA of Pacific Ocean salmon

Restriction assay of mtDNA has been made in 6 salmon species form the genus Oncorhynchus and one species from the related genus, i.e. Salvelinus malma. The size of the mitochondrial genome was found to be identical and equal to 16.7 kilobases. The digestion patterns of mtDNA cleaved by 5 restriction endonucleases (Eco RI, Bgl I, Bgl II, Hind III, and Pst I) were used for analysis of the levels of interspecific variation and for estimation the matrix of mtDNA sequence differentiation. It was found that the level of nucleotide sequence divergence (p) in the genus Oncorhynchus varies within 1.7-6.7%. Minimum p value was observed in a pair O. keta--O. gorbuscha, maximum one--between O. masu and other species. With respect to similarity in their mtDNA, three groups may be distinguished: 1) O. gorbuscha--O. keta; 2) O. nerka--O. kisutch, O. tschawytscha; 3) O. masu. Mean value of intergeneric level of sequence divergence between Oncorhynchus and Salvelinus was found to be equal to 8%. On the basis of mtDNA analysis, the dendrogram of similarity of the species was plotted which is consistent in principle with current viewpoints on phylogenetic relations among the Pacific salmon.     

Localization of the multigene Lpm locus in chromosome 9 of the American mink

The results of genetic study on linkage of Lpm locus with peptidase B gene are presented. Investigation of 111 offspring back-crosses shows that Lpm allotypes and allelic variants of peptidase B are inherited in concert. The frequency of recombination between the Lpm locus and peptidase B gene is 11 +/- 3% in male. Since it was earlier established that peptidase B gene is a marker of chromosome 9, our data indicate that the Lpm loci family is situated in the chromosome 9 of domestic mink.     

Regular proteinaceous layers ofThermococcus stetteri cell envelope

Proteinaceous layers of theThermococcus stetteri cell envelope were investigated and found to consist of regularly arrayed subunits 18 nm in diameter. According to the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, two major proteins were present. They were glycosylated and had molecular weights of 80,000 and 210,000. In addition to two external regular proteinaceous layers, cells ofT. stetteri were found to have internal regular layers tightly attached to the cytoplasmic membrane. In the region of flagella attachment to the cell, polar membrane-like structures were found in the cytoplasm.     

Phylogeography of mitochondrial DNA in South Asian Dolly Varden char Salvelinus curilus Pallas, 1814 (Salmoniformes, Salmonidae): mediated gene introgression?

In 41 individuals of South Asian Dolly Varden char Salvelinus curilus, nucleotide sequences of tRNA-Pro gene fragment (27 bp) and mtDNA control region (483-484 bp) were analyzed. The fish were collected in 20 localities covering virtually the whole range of the species: Kuril Islands, Sakhalin Island. and Primorye. In addition, six individuals of three other char species (S. albus, S. malma, and S. leucomaenis), which are closely related to S. curilus and inhabit the Russian Far East, were examined. In all, we detected 12 different variants of mtDNA haplotypes that formed three distinct groups differing in 14--20 nucleotide positions. The first group consisted of six haplotypes found in S. curilus in Kuril Islands, Sakhalin, and Primorye (mtDNA phylogroup OKHOTSKIA). The second group comprised four haplotypes representing the mtDNA phylogroup BERING, which had been described earlier (Brunner et al, 2001); they were found in S. curilus in Kuril Islands and Sakhalin, as well as in S. albus and S. malma in Kamchatka and northern Kurils. The third group included two haplotypes detected in S. leucomaenis. The existence of two mtDNA lineages (OKHOTSKIA and BERING) in S. curilus from Kurils and Sakhalin was explained by hybridization and DNA transfer from S. malma to S. curilus. The absence of the BERING haplotypes in S. curilus from Primorye water reservoirs is related to the physical isolation of the Sea of Okhotsk and Sea of Japan basins in past epochs. On the basis of comparing phylogenetic trees, constructed from the data on allozyme and mtDNA variation, we suggest that in this case, an indirect transfer of mtDNA in Alpinoid chars--> S. malma-->S. curilus chain could occur.     

ESM-1 silencing decreased cell survival,migration, and invasion and modulated cell cycle progression in hepatocellular carcinoma

Amino Acids - Endothelial cell-specific molecule-1 (ESM-1) is a secretory proteoglycan comprising a mature polypeptide of 165 amino acids and a single dermatan sulfate. The aim of this study was to...     

Impedance Matching Induce High Transmission and Flat Response Band-Pass Plasmonic Waveguides

We consider a model utilizing the concept of impedance matching, which can be applied to design the coupled cascaded plasmonic cavity waveguide with desired properties. We use a transfer matrix method to obtain its transmission and dispersion diagrams. Base on this method, we demonstrate that a band-pass metal–dielectric–metal plasmonic filter with quasi-flat group velocity and tunable bandwidth can be achieved.     

Divergence patterns of banding sequences in different polytene chromosome arms reflect relatively independent evolution of different genome components

Divergence patterns of the banding sequences from the chromosomal arms A, C, D, E, and F were compared in 63 species of the genus Chironomus. Evaluation of the number of breakpoints between the pairs of inverted banding sequences and the analysis of the lengths of the conserved segments in the chromosomal arms in the chironomid species examined showed that different arms evolved relatively independently and at different rates. No direct correlation between the arm length and the breakpoints number was observed. The length of the conservative segment was not fixed, but was arm-specific. Robustness and fidelity of the estimates of phylogenetic relationships between the species examined increased with the arm number, i.e., with the genome proportion included in the analysis.     

Thermophilic microbial communities of deep-sea hydrothermal environments

The latest publications on the phylogenetic and functional diversity of thermophilic prokaryotes inhabiting thermal deep-sea environments are reviewed. Along with general physicochemical characterization of the biotope studied, certain adaptation mechanisms are discussed that are peculiar to the microorganisms inhabiting it. A separate chapter addresses phylogenetic analysis of deep-sea hydrothermal microbial communities and uncultivated microorganisms recently discovered therein using molecular biological techniques. Physiological groups of thermophilic microorganisms found in deep-sea hydrotherms are considered: methanogens, sulfate-, iron-, and sulfur-reducers, aerobic hydrogen-oxidizing prokaryotes, aerobic and anaerobic organotrophs. In most cases, the isolates represent novel taxa.     

Quantitative changes in characteristics of immunity in longlivers

In 93 persons aged 90 to 103 years old the subpopulation compositon of lymphocytes and the level of thymic serum activity (TSA) was studied. In the presence of polymorbidity the low level of TSA was observed in 81% of examinees, with the quantitative deficiency in the relative and absolute number of CD3+CD8+ T-lymphocytes (62% and 78% respectively) and the excess in the number CD3+CD4-CD8- T-lymphocytes (42% and 57% respectively). Among CD3+CD4-CD8- T-lymphocytes cells with phenotypes CD3+/-CD4-CD8-CD16- and CD3+CD4-CD16+ were determined. In prolonged imunomonitoring the reciprocacity of changes in the amount of CD3+/-CD4-CD8-CD16- T-lymphocytes was established in relation to the level of TCA and the number of CD3+CD8+ T-lymphocytes. The reversibility of these changes is indicative of the potential of reactivity of the immune system in longlivers. The positive result of laser therapy in persons with quantitative deficiency of CD3+CD8+ T-lymphocytes and the presence of cells with phenotype CD3+/-CD4-CD8-CD16- was associated with the restoration of the size of CD3+CD8+ subpopulation and a decrease in an amount of CD3+/-CD4-CD8-CD16-. The unfavorable prognostic sign was, seemingly, the quantitative deficiency of CD3+CD8+ T-lymphocytes with the low level of TCA in the absence of CD3+/-CD4-CD8-CD16- T-lymphocytes.