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首页> 外文期刊>Journal of bacteriology >Structural and Biological Characterization of a Capsular Polysaccharide Produced by Staphylococcus haemolyticus
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Structural and Biological Characterization of a Capsular Polysaccharide Produced by Staphylococcus haemolyticus

机译：溶血性葡萄球菌产生的荚膜多糖的结构和生物学特性

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The DNA sequence of the genome of Staphylococcus haemolyticus JCSC1435 revealed a putative capsule operon composed of 13 genes in tandem. The first seven genes (capABCDEFGSh) showed ≥57% similarity with the Staphylococcus aureus cap5 or cap8 locus. However, the capHIJKLMSh genes are unique to S. haemolyticus and include genes encoding a putative flippase, an aminotransferase, two glycosyltransferases, and a transcriptional regulator. Capsule-like material was readily apparent by immunoelectron microscopy on bacteria harvested in the postexponential phase of growth. Electron micrographs of a JCSC1435 mutant with a deleted cap region lacked the capsule-like material. Both strains produced small amounts of surface-associated material that reacted with antibodies to polyglutamic acid. S. haemolyticus cap genes were amplified from four of seven clinical isolates of S. haemolyticus from humans, and three of these strains produced a serologically cross-reactive capsular polysaccharide. In vitro assays demonstrated that the acapsular mutant strain showed greater biofilm formation but was more susceptible to complement-mediated opsonophagocytic killing than the parent strain. Structural characterization of capsule purified from S. haemolyticus strain JCSC1435 showed a trisaccharide repeating unit: ?3-α-l-FucNAc-3-(2-NAc-4-N-Asp-2,4,6-trideoxy-β-d-Glc)-4-α-d-GlcNAc-. This structure is unique among staphylococcal polysaccharides in that its composition includes a trideoxy sugar residue with aspartic acid as an N-acyl substituent.
机译：溶血性葡萄球菌JCSC1435基因组的DNA序列揭示了一个由13个基因串联组成的推定的胶囊操纵子。前七个基因（ capABCDEFG Sh ）与金黄色葡萄球菌cap5 或 cap8 基因座的相似性≥57％。但是， capHIJKLM Sh 基因对于 S是唯一的。包括溶血性溶血酶，转氨酶，两个糖基转移酶和转录调节子。通过免疫电子显微镜对在指数后生长阶段收获的细菌很容易看到胶囊状物质。具有 cap 区域缺失的JCSC1435突变体的电子显微照片缺少胶囊状物质。两种菌株均产生少量与抗聚谷氨酸抗体反应的表面相关物质。 S。从七个 S临床分离株中的四个分离出溶血性帽基因。来自人类的溶血性，其中三个菌株产生了具有血清学交叉反应性的荚膜多糖。体外试验表明，与亲本菌株相比，荚膜突变株显示出更大的生物膜形成，但更容易被补体介导的调理吞噬作用。从 S纯化的胶囊的结构表征。溶血性菌株JCSC1435显示了一个三糖重复单元：α3-α-1-FucNAc-3-（2-NAc-4- N -Asp-2,4,6-三苯氧基- β-d-Glc）-4-α-d-GlcNAc-。该结构在葡萄球菌多糖中是独特的，因为其组成包括带有天冬氨酸作为 N -酰基取代基的三脱氧糖残基。

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