Library Faculty/Staff Scholarship and Research
Permanent URI for this collectionhttp://hdl.handle.net/1903/11
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Item On the phagocytosis in vitro of strains of Yersinia pseudotuberculosis after treatment with certain detergents and lipid solvents(Bulgarian Academy of Sciences, 1976) Baykousheva, S.; Veljanov, D.Reproduced from SciFinder with permission from the Chemical Abstracts Service. The addn. of Na lauryl sulfate [151-21-3] or petroleum ether to Y. pseudotuberculosis grown in a medium contg. 10% glycerol at 28° (conditions under which V and W antigens are not synthesized) significantly increased the phagocytosis of the bacterial cells by rabbit blood. The addn. of Na periodate or trypsin [9002-07-7] produced variable degrees of phagocytosis dependent on the virulence of the strains tested. The role of lipid synthesis in the restoration of phagocytosis at 28° is discussed.Item Specificities in the phospholipid and fatty acid composition of the stable protoplast type L-form of Escherichia coli B(1984) Gumpert, J.; Schade, W.; Krebs, B.; Baykousheva, S.; Ivanova, E.; Toshkov, A.The stable protoplast type L-form cells of E. coli B are twice richer in the extractable lipids than in the parent form. No qualitative differences in the phospholipid and fatty acid composition were found. However, the quantity of C14:0, C17:Δ, and C18:0 differ considerably. Unsaturated fatty acids are prevalent in the L-form cells.Item Electron-microscopic demonstration of the localization of adenosinetriphosphatase in Bacillus subtilis(1984) Cherepova, N.; Baykousheva, S.; Ilieva, K.Histochemical studies and electron microscopy of Bacillus subtilis revealed the presence of ATPase in various subcellular fractions. The enzyme was preferentially localized in mesosomes, cytoplasmic membrane, periplasmic space, and cell wall.Item Suppression of serine protease secretion and sporulation in Bacillus subtilis by detergents(1987) Baykousheva, S.; Ilieva, K.In Bacillus subtilis grown under aeration at 37° for 24 h in liquid nutrient medium containing the nonionic detergents octylphenol-polyethylene glycol ether or polyoxyethylene monocetyl ether, increasing the concentrations of the detergents led to a decrease in the amount of protease secreted from the cells and abolished sporulation. Possible mechanisms by which these detergents caused these actions are discussed.Item Fatty acid composition of lipids of Escherichia coli W 1655 F+ and its stable protoplast type L-form(1982) Gumpert, J.; Schade, W.; Krebs, D.; Baykousheva, S.; Ivanova, E.; Toshkov, A.The comparative fatty acid analysis of extractable and non-extractable lipids of Escherichia coli W 1655 F+ and its stable protoplast type L-form shows quantitative as well as qualitative differences. From 10 different fatty acids obtained, 16:0, 17:0 and 18:0 were present at about the same quantities in the lipid fractions of the bacterial and L-form. The absence of larger amounts of 12:0, 14:0, and 14:beta-hydroxy fatty acids in the non-extractable L-form lipids reflects the loss of the cell wall in L-form cells. The 16:1 fatty acid was found in L-form lipids, only. This qualitative difference and the 2-3 times higher content of 18:1 in L-form lipids and the 7 times lower content of cyc-19:0 in extractable lipids of the L-form may be interpreted as alterations characteristic of the changed composition of the cytoplasmic membrane in the L-form cells.Item Secretion of proteins by Bacillus subtilis 168 grown in the presence of membrane active agents (alcohols)(1988) Baykousheva, S.Sodium dodecyl sulphate-polyacrylamide gel electrophoresis was used to study the composition of proteins secreted by the Gram-positive microorganism Bacillus subtilis strain 168 when the latter was grown in the presence of primary alcohols (methanol, ethanol, 1-propanol and 1-butanol). These membrane-active agents had different effects on the pattern of proteins exported by B. subtilis. The secretion of some proteins was inhibited by the alkanols while that of others was stimulated, depending on the type of drug used. All alcohols were found to decrease the activity of extracellular enzymes such as alpha-amylase and serine protease without affecting significantly the activity of these enzymes when tested in vitro. The observed effects might be due to the ability of these agents to perturb the structure of biological membranes, thus interfering with the process of protein translocation through the lipid bilayers.