排序方式: 共有29条查询结果,搜索用时 15 毫秒
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N Corcionivoschi LA Alvarez TH Sharp M Strengert A Alemka J Mantell P Verkade UG Knaus B Bourke 《Cell host & microbe》2012,12(1):47-59
Reactive oxygen species (ROS) play key roles in mucosal defense, yet how they are induced and the consequences for pathogens are unclear. We report that ROS generated by epithelial NADPH oxidases (Nox1/Duox2) during Campylobacter jejuni infection impair bacterial capsule formation and virulence by altering bacterial signal transduction. Upon C. jejuni invasion, ROS released from the intestinal mucosa inhibit the bacterial phosphotyrosine network that is regulated by the outer-membrane tyrosine kinase Cjtk (Cj1170/OMP50). ROS-mediated Cjtk inactivation results in an overall decrease in the phosphorylation of C. jejuni outer-membrane/periplasmic proteins, including UDP-GlcNAc/Glc 4-epimerase (Gne), an enzyme required for N-glycosylation and capsule formation. Cjtk positively regulates Gne by phosphorylating an active site tyrosine, while loss of Cjtk or ROS treatment inhibits Gne activity, causing altered polysaccharide synthesis. Thus, epithelial NADPH oxidases are an early antibacterial defense system in the intestinal mucosa that modifies virulence by disrupting bacterial signaling. 相似文献
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W G Niehaus A Torkelson A Kisic D J Bednarczyk G J Schroepfer 《The Journal of biological chemistry》1970,245(15):3790-3797
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Kisic M Matamoros T Nevot M Mendieta J Martinez-Picado J Martínez MA Menéndez-Arias L 《The Journal of biological chemistry》2011,286(23):20615-20624
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T N Pajewski J S Brabson A Kisic K S Wang M D Hylarides E M Jackson G J Schroepfer 《Chemistry and physics of lipids》1989,49(4):243-263
5 alpha-Cholest-8(14)-en-3 beta-ol-15-one is a potent inhibitor of cholesterol biosynthesis which has significant hypocholesterolemic activity upon oral administration to rodents and nonhuman primates. In the present study the metabolism of the 15-ketosterol has been investigated after the oral administration of a mixture of [2,4-3H]5 alpha-cholest-8(14)-en-3 beta-ol-15-one and [4-14C]cholesterol to 8 baboons. Blood samples were obtained at 4, 8, 12, 16, and 24 h after administration of the labeled sterols. Clear differences in the time courses of the levels of 3H and 14C in plasma were observed. 3H in plasma showed maximum values at 4 to 8 h, whereas maximum values for the levels of 14C were observed much later. 3H in plasma was shown to be primarily in the form of its metabolites, i.e. esters of the 15-ketosterol, cholesterol, and cholesteryl esters. The levels of the 15-ketosterol and of each of these metabolites showed different changes with time. The labeled cholesterol (and the cholesterol moiety of the cholesteryl esters), formed from the [2,4-3H]-15-ketosterol, was characterized by chromatography and by purification by way of its dibromide derivative. At 24 h after the administration of the labeled sterols, the distribution of 3H in plasma lipoprotein fractions paralleled that of 14C, with most of the 3H and 14C in high density lipoprotiens (HDL) and low density lipoproteins (LDL). Almost all of the 3H in HDL and in LDL was found as cholesterol, cholesteryl esters and esters of the 15-ketosterol. The distribution of 3H in HDL and in LDL of the free 15-ketosterol, esters of the 15-ketosterol, cholesterol, and cholesteryl esters was similar to that of plasma, thereby indicating no unusual concentration of any of the 3H labeled components in HDL or LDL. 相似文献
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Countercurrent distribution of inosol lipids of plant seeds 总被引:2,自引:0,他引:2
The inositol lipids of plant seeds consist of phosphatidyl inositol, the phytoglycolipids, and a previously uncharacterized ceramide-phosphate-polysaccharide. These three species have been separated from each other and from the common glycerophosphatides by a series of simple countercurrent distributions, first as the naturally occurring Ca-Mg salts and subsequently in the Na salt form. The new ceramide-phosphate-polysaccharide is present in each of the four plant phosphatides examined (corn, soybean, flax, safflower). It is devoid of glucosamine but contains the other carbohydrate components commonly found in the phytoglycolipids. The basic structural unit of the new glycolipid consists of a ceramide-phosphate-inositol-hexuronic acid moiety to which the other sugars (galactose, mannose, arabinose) are attached. Flax ceramide-phosphate-polysaccharide has fucose in addition to the other sugars. 相似文献
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G J Schroepfer A Christophe D H Needleman A Kisic B C Sherrill 《Biochemical and biophysical research communications》1987,146(3):1003-1008
The effect of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one, a potent inhibitor of cholesterol synthesis with marked hypocholesterolemic activity, on the intestinal absorption of exogenous cholesterol has been studied in lymph-cannulated rats. Administration of the 15-ketosterol at a level of 0.05% in a rat chow diet for 10 days was associated with a marked decrease (-64%) in the absorption of cholesterol. 相似文献
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A method is described for determining the long-chain base content of glycosphingolipids after acid hydrolysis, using the new reagent fluorescamine. The reaction is sensitive and can be used to characterize or measure glycosphingolipids in quantities routinely separated by thin-layer chromatography. 相似文献
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G J Schroepfer T N Pajewski M Hylarides A Kisic 《Biochemical and biophysical research communications》1987,146(3):1027-1032
The metabolism of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one (I), a potent inhibitor of cholesterol synthesis with marked hypocholesteremic activity, has been studied in a nonhuman primate. A mixture of [2,4-3H]-I and [4-14C]-cholesterol was administered to a male baboon in the form of a feedball. Blood was samples at 4, 8, 12, 16, and 24 hr. Detailed analyses of the plasma lipids indicated very rapid absorption of I (relative to cholesterol) and metabolism to cholesterol, cholesteryl esters, and esters of I. The labeled cholesterol was characterized by chromatographic techniques and by purification by way of its dibromide derivative. The levels of 3H in plasma associated with I, esters of I, cholesterol, and cholesteryl esters each showed a different time course. By 24 hr after the administration of [2,4-3H]-I, most of the 3H in plasma was associated with cholesterol and cholesteryl esters. The levels of total 3H and 14C in plasma at various times after the administration of the mixture of [2,4-3H]-I and [4-14C]-cholesterol differed markedly with 3H showing a maximum value at 4 hr and 14C showing a maximum value at 24 hr. 相似文献