Genetic heterogeneity of heat shock protein synthesis as a factor determining the resistance to stressors in mammalia

The relationship between the levels of 70 kDa family heat shock protein (Hsp) synthesis and lymphocyte sensitivity to stressors was investigated. Lymphocyte cultivation in mitogen deprived culture medium and/or the cell treatment with alkylating agents have been used as a stress challenge. Model experiments with two inbred murine strains genetically contrasting by the sensitivity to alkylating agents demonstrated that the basic level of Hsp synthesis depends on genotype. The quantity Hsp70 mRNA, as well as intracellular level of the proteins, in BALB/c was significantly higher than those in C57BL/6 mice. The mice, which were characterized by higher Hsp levels, demonstrated higher resistance to alkylating agent action. The induction of surplus amount of Hsp by heat shock increased the cell resistance to an alkylating agent melphalan. Lymphocyte isolated from high Hsp producers BALB/c mice were more resistant to apoptotic signals induced by mitogen deprivation.     

Experimental non-culturable Vibrio cholerae eltor and its biological properties

In experiments with the cultivation of V. cholerae eltor under the conditions of high salt concentration, as well as low temperature and deficiency in nutrient substances, uncultivable forms (UF) of toxigenic and nontoxigenic vibrios were obtained. The absence of growth of seeded vibrios after the filtration of samples (with a filter of 0.22 micron), the preservation of specific antigenic determinants and the initial set of genes, changes in the morphology of cells (small size, coccoid form with the flagella retained) confirm the transition of V. cholerae eltor under study into the uncultivable state which, under unfavorable conditions, more rapidly develops in toxigenic vibrios than in nontoxigenic ones. The analysis of the INT-reductase activity of UF disintegrates revealed that they had endogenic respiration whose activity increased (4.5- to 6.5-fold) in the presence of the exogenic intermediates of the Krebs cycle. The uncultivable forms of the vibrios retain genes responsible for pathogenicity, as well as their antigenic determinants.     

Cryptic splice sites and split genes

We describe a new program called cryptic splice finder (CSF) that can reliably identify cryptic splice sites (css), so providing a useful tool to help investigate splicing mutations in genetic disease. We report that many css are not entirely dormant and are often already active at low levels in normal genes prior to their enhancement in genetic disease. We also report a fascinating correlation between the positions of css and introns, whereby css within the exons of one species frequently match the exact position of introns in equivalent genes from another species. These results strongly indicate that many introns were inserted into css during evolution and they also imply that the splicing information that lies outside some introns can be independently recognized by the splicing machinery and was in place prior to intron insertion. This indicates that non-intronic splicing information had a key role in shaping the split structure of eukaryote genes.     

Chemcial aspects of the energy process in nitrate reduction in different representatives of soil microflora

Chemical aspects of dissimilatory nitrate reduction were studied by mass spectrometry in the following soil bacteria: Bacillus filaris, Bacillus polymyxa and Pseudomonas denitrificans. Chemical peculiarity of this process in spore-forming soil bacteria is the simultaneous operation of two energy processes: denitrification and nitrate respiration. The first process is terminated by the formation of molecular nitrogen, the second, by the production of ammonia. The quantitative ratio between these processes demonstrates the advantage of nitrate respiration in the overall energy pathway of nitrate dissimilation. Pseudomonas denitrificans maintains the abilityfor intensive gas production as a result of denitrification upon long storage on artificial media: ca. 34 per cent of the nitrate nitrogen is reduced to gaseous forms of nitrogen.