On the phagocytosis in vitro of strains of Yersinia pseudotuberculosis after treatment with certain detergents and lipid solvents

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

Suppression of serine protease secretion and sporulation in Bacillus subtilis by detergents

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

Arachidonic acid formed by peroxisomal β-oxidation of 7,10,13,16- docosatetraenoic acid is esterified into 1-acyl-sn-glycero-3-phosphocholine by microsomes

Available online at http://www.jbc.org/content/269/28/18390.full.pdf+htmlPeroxisomal beta-oxidation of linoleic acid and arachidonic acid was depressed when 1-palmitoyl-sn-glycero-3-phosphocholine and microsomes were included in incubations. This reduction was due to the esterification of the substrate into the acceptor by microsomal 1-acyl-sn-glycero-3- phosphocholine acyltransferase. The first cycle of the beta-oxidation of 7,10,13,16-docosatetraenoic acid was independent of 1-acyl-sn-glycero-3-phosphocholine and microsomes. However, when arachidonate was produced it was esterified rather than serving as a substrate for continued beta-oxidation. When arachidonate and linoleate were incubated with peroxisomes alone, 2-trans-4,7,10-hexadecatetraenoic acid and 2-trans-4-decadienoic acid were the respective end products of beta-oxidation. 2-Oxo-8,11-heptadecadienone, a catabolite produced from linoleate, was most likely a nonenzymatic decarboxylation product of 3-oxo-9,12-octadecadienoic acid. In addition to the termination of beta-oxidation by microsomal-peroxisomal communication, our results with linoleate and arachidonate suggest that the reaction catalyzed by 2-trans-4-cis-dienoyl-CoA reductase is the control step in double bond removal. In addition, the beta-ketothiolase step may play a regulatory role in the peroxisomal beta-oxidation of linoleate but not arachidonate or 7,10,13,16-docosatetraenoic acid

Further studies on the metabolic changes in strains of Salmonella typhimurium and Yersinia pseudotuberculosis after treatment with some detergents and lipid solvents

In Bulgarian.Reproduced from SciFinder, with permission from the Chemical Abstracts Service. Incubation of S. typhimurium and Y. pseudotuberculosis in 30% petroleum ether at 37° inhibited respiration more than did 0.01-0.03% Na lauryl sulfate [151-21-3]. After a 72-h incubation in 10% glycerol [56-81-5] the respiration level returned to, or approached normal. Petroleum ether also inhibited dehydrogenase [9035-82-9] activity and glycolysis more than did Na lauryl sulfate. Incubation in glycerol also reversed this inhibition. Na lauryl sulfate completely and irreversibly inhibited phosphatase [9013-05-2] at pH 5.4 and 8.0. Petroleum ether inhibited phosphatase at pH 5.4 in Y. pseudotuberculosis and at pH 8.0 in S. typhimurium

Reevaluation of the pathways for the biosynthesis of polyunsaturated fatty acids

Recent studies refute the commonly accepted, but untested, hypothesis that 7,10,13,16-22:4 and 7,10,13,16,19-22:5 are desaturated at position 4 by a microsomal acycl-CoA-independent desaturase. The synthesis of 4,7,10,13,16,19-22:6 occurs via the following reaction sequence: 4,7,10,13,16,19-22:6. The synthesis of 4,7,10,10,13,16-22:5 from 7,10,13,16-22:4 takes place via an analogous pathway. According to these pathways the 24-carbon acids that are made in the endoplasmic reticulum move to a site for partial beta-oxidation, 4,7,10,13,16-22:5 and 4,7,10,13,16,19-22:6, then move back to the endoplasmic reticulum where they are used as substrates for membrane lipid biosynthesis. The ability of fatty acid to serve as a substrate for continued peroxisomal beta-oxidation, versus its transfer out of peroxisomes for subsequent endoplasmic reticulum-associated esterification reactions, may be an important control for regulating membrane lipid fatty acid composition. Indeed, the revised pathways of polyunsaturated fatty acid biosynthesis imply that there is considerable intracellular movement endoplasmic reticulum. In addition, these revised pathways require that two 18-carbon and two 24-carbon acids are substrates for desaturation at position 6. Also, as linoleate and linolenate are metabolized, respectively, to 6,9,12,15,18-24:5 and 6,9,12,15,18,21-24:6, three n-6 acids and three n-3 acids are substrates for malonyl-CoA dependent chain elongation. It remains to be determined how many microsomal enzymes ancillary enzymes are expressed in tissues whose membrane lipids accumulate very long-chain polyunsaturated acids with up to 36 carbon atoms

Ultracytochemical localization of ATP-hydrolysing activity in vegetative cells, spores and isolated cytoplasmic membranes of Bacillus subtilis 168

The localization of ATP-hydrolysing activity in vegetative cells, spores and isolated membranes of Bacillus subtilis 168 was studied by a cytochemical method combined with electron microscopy. The activity was located mainly in the cytoplasmic membrane and the mesosomes, and was also found in the inner layer of the cell wall facing the cytoplasmic membrane. Activity was also detected in the cross-membranes of dividing cells and in spore coats. The product of the reaction was observed either as fine electron-dense granules incorporated into the membranes, or as high-contrast lead precipitates on the surfaces of the membranes

Specificities in the phospholipid and fatty acid composition of the stable protoplast type L-form of Escherichia coli B

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

Glucose isomerase

Review. In Bulgaria

Bacterial membranes

In Bulgaria

Secretion of proteins by Bacillus subtilis 168 grown in the presence of membrane active agents (alcohols)

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