A novel means of self-protection, unrelated to toxin activation, confers immunity to the bactericidal effects of the Enterococcus faecalis cytolysin.
A novel means of self-protection, unrelated to toxin activation, confers immunity to the bactericidal effects of the Enterococcus faecalis cytolysin.
复制标题
一种与毒素激活无关的新型自我保护方法，赋予对粪肠球菌溶细胞素的杀菌作用的免疫力。
DOI：
10.1128/iai.67.7.3339-3347.1999
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发表时间：
1999
影响因子：
3.1
通讯作者：
Gilmore,MS
中科院分区：
文献类型：
--
作者：
Coburn,PS;Hancock,LE;Booth,MC;Gilmore,MS
由于粪肠球菌对大多数抗生素产生耐药性，粪肠球菌已成为临床上普遍存在的问题。E.粪便是一种新的细菌毒素，导致疾病的严重性。它由两个结构亚基组成，它们共同具有溶血和杀菌活性。这两种毒素亚基都编码在一个复杂的操纵子中，该操纵子通常位于信息素反应质粒上。缺乏这种质粒的粪杆菌菌株对溶细胞素的杀菌作用敏感。本研究描述了位于pAD 1溶细胞素操纵子3 '末端的一种新的溶细胞素免疫决定簇。缺失分析和特异性突变将免疫功能分离到单一开放阅读框。特异性诱变实验证明，溶细胞素免疫与溶细胞素激活剂（CylA）表达无关，如先前提出的。然而，溶细胞素免疫是在与CylA相同的转录本上编码的，并且在CylA的3′端编码，并且先前免疫与CylA之间的关联可以归因于Tn917插入的极性行为。
Enterococcus faecalishas become a pervasive clinical problem due to the emergence of resistance to most antibiotics. The cytolysin ofE. faecalisis a novel bacterial toxin that contributes to the severity of disease. It consists of two structural subunits, which together possess both hemolytic and bactericidal activity. Both toxin subunits are encoded in a complex operon frequently harbored on pheromone-responsive plasmids.E. faecalisstrains lacking such plasmids are susceptible to the bactericidal effects of the cytolysin. A novel cytolysin immunity determinant at the 3′ end of the pAD1 cytolysin operon is described in the present study. Deletion analysis and specific mutagenesis isolated the immunity function to a single open reading frame. Specific mutagenesis experiments demonstrate that cytolysin immunity is unrelated to cytolysin activator (CylA) expression as previously proposed. Cytolysin immunity is, however, encoded on the same transcript as and 3′ to CylA, and previous associations between immunity and CylA can be ascribed to the polar behavior of Tn917insertion.