Plasmid inverted repeats provide for duplication or precise excision of DNA inserts

A plasmid containing inverted repeats is constructed in Bacillus subtilis. Insertion of DNA fragments into the plasmid inverted repeats results either in the precise excision of the insert or in its duplication in the opposite inverted repeat. These rearrangements are due to the presence of inverted repeats only. Two recombination events are possibly responsible for these phenomena. During the first step of the recombination two plasmid monomers form a dimer molecule. During the second step the intramolecular recombination between the direct repeats in the dimer structure leads to the formation of two rearranged plasmid monomers devoid of insertion or containing two DNA inserts. Proposed dimeric intermediate is unstable in B. subtilis. However, it is isolated from Escherichia coli recA, cells. Plasmids containing the inverted repeats can serve as a model to study plasmid recombination in B. subtilis cells.     

The phages of halophilic vibrios and their use]

The range of the lytic activity of 46 phages of parahemolytic vibrios isolated from lysogenic strains, sea water samples, crabs and mussels has been studied. The phages are represented by virions belonging to morphological groups II, IV, V according to the phage classification currently used in Russia and to different serological groups. No relationship between the sensitivity of vibrio strains to the phages under study and the specificity of serotypes O and K has been established. The preparation of diagnostic phage [see text] suitable for the identification of 82% of strains of parahemolytic vibrios has been proposed.     

Synthesis and immunochemical study of the antigenic determinant of the H-2Db molecule of the murine major histocompatibility complex

Primary structure of murine class I histocompatibility antigens has been analysed to select possible antigenic determinant. Hexapeptide Leu-Gln-Gln-Leu-Ser-Gly, homologous to the region 95-100 of the H-2Db antigen heavy chain, was synthesised by stepwise elongation of peptide chain beginning from the COOH-terminal Gly. Rabbit anti-hexapeptide antibodies were obtained and shown to interact specifically with purified H-2Db antigen as well as with the native antigen on cell surface. These antibodies bind to lymphocytes of H-2b haplotype (C57BL/6 mice) but not H-2d (BALB/c) or H-2k (CBA). These data suggest that the region 95-100 is responsible for serologic differences between the alleles of H-2 antigens, i.e. it may be a xenotypic as well as an allotypic antigenic determinant. The latter was confirmed by study of interaction of the hexapeptide with allogeneic monoclonal antibodies specific to H-2Db antigen.     

Production of proteinases in the process of developing cultures of Streptomyces thermovulgaris T-54

The secretion of some proteolytic enzymes by Streptomyces thermovulgaris T 54 was studied using artificial chromogenic substrates of proteinases. Maximum accumulation of the enzymes hydrolysing Z-Glu-pNA and Z-Ala-Ala-Leu-pNA occurred during autolysis of the culture. Two peaks of activity were observed, when DNP-Gly-Gly-Ile-Arg was used as a substrate, one of them being correspondent to prevalence of dense colonies in the culture and the other to the prevalence of friable networks of hyphae.     

The "Goldilocks Effect" in Cystic Fibrosis: identification of a lung phenotype in the <Emphasis Type="Italic">cftr</Emphasis> knockout and heterozygous mouse

Background  

Cystic Fibrosis is a pleiotropic disease in humans with primary morbidity and mortality associated with a lung disease phenotype. However, knockout in the mouse of cftr, the gene whose mutant alleles are responsible for cystic fibrosis, has previously failed to produce a readily, quantifiable lung phenotype.     

Early diagnostics of hemorrhagic fever with renal syndrome on the basis of the use of Pumala virus recombinant nucleocapsid protein

Pumala virus recombinant nucleocapsid protein was used for the early diagnosis of haemorrhagic fever with renal syndrome. Specific IgM in the sera of patients could be determined by the IEA technique as early as on days 2-3 from the onset of the disease. The diagnostic effectiveness of the test-system was 95% and its specificity was 98%.     

Phenotype characteristic of the ionomycin-resistant CD4+ subset of the peripheral blood T-lymphocytes

The differential sensitivity of peripheral blood (PB) CD4+ T lymphocytes to the calcium ionophore ionomycin was investigated. Effect of ionomycin exerted on T cells was time- and dose-dependent. We have shown that resistant cells belonged to some distinct T cell subsets. The resting naive CD4+CD45RA+ T cells showed a little, if any, resistance to ionomycin treatment. The primed CD4+CD45R0+ memory T cells behaved similarly as did ionomycin-resistant (IR) cells. Although IR CD4+ T cells had a typical "memory" phenotype, some quantitative differences were found in expression of CD11a, CD28, CD29, CD62L and CD243 markers between PB CD4+CD45R0+ T cells and corresponding IR cells.     

In vitro and in vivo studies of RNAse of Bacillus intermedius

Cytotoxicity of RNAase from Bacillus intermedius was studied in vitro and in vivo. It was shown that the enzyme had slightly pronounced cytotoxicity according to the tests with inhibition of cell proliferation and biosynthesis of cell nucleic acids. The RNAase was also shown to impair the vital staining by neutral red. The efficiency of the impairment much more depended on the enzyme catalytic activity than on the proliferation and biosynthesis of nucleic acids. In vivo toxicity of RNAase from B. intermedius was 3-5 times higher than that of pancreatic RNAase. Possible mechanisms of the different toxicity of the enzymes are discussed.     

The Potential Crosstalk Between the Brain and Visceral Adipose Tissue in Alzheimer’s Development

Neurochemical Research - The bidirectional communication between the brain and peripheral organs have been widely documented, but the impact of visceral adipose tissue (VAT) dysfunction and its...