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首页> 外文期刊>Infection and immunity >Polysaccharide side chains are not required for attaching and effacing adhesion of Escherichia coli O157:H7.
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Polysaccharide side chains are not required for attaching and effacing adhesion of Escherichia coli O157:H7.

机译：大肠杆菌O157：H7的附着和脱落附着不需要多糖侧链。

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Escherichia coli of the serotype O157:H7 is an enterohemorrhagic human pathogen which demonstrates attaching and effacing adhesion to colonocytes in vivo and to epithelial cells grown in tissue culture. Transposon TnphoA mutants of E. coli O157:H7 strain CL-8 were produced. Two of 300 alkaline phosphatase positive mutants, designated JB6 and JB27, did not express O157 side chains as assessed by agglutination with specific polyclonal O157 antiserum, silver staining of lipopolysaccharide extracts separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western immunoblots with polyclonal O157-specific antiserum. Both O157-negative mutants and the parent strain demonstrated localized adherence to HEp-2 cells when examined by Giemsa staining and bright-field microscopy. Furthermore, both O157-negative mutants showed enhanced adherence to HEp-2 cells compared with the parent strain when assessed by quantification of adherent bacterial CFUs. The parent strain, CL-8, and both of the mutants produced fluorescent foci when adherent bacteria and HEp-2 cells were stained with fluorescein isothiocyanate-labelled phalloidin. Transmission electron microscopy confirmed attaching and effacing adherence of strain CL-8 and the OO7-negative mutants to HEp-2 cells. These findings indicate that mutants deficient in O157 polysaccharide repeats exhibit adherence to tissue culture cells in vitro and that O157 polysaccharide repeats are not required to produce the attaching and effacing lesion.
机译：血清型O157：H7的大肠杆菌是一种出血性人类病原体，它表现出对体内结肠细胞和组织培养物中生长的上皮细胞的附着和消失。产生了大肠杆菌O157：H7菌株CL-8的转座子TnphoA突变体。 300个碱性磷酸酶阳性突变体中的两个，命名为JB6和JB27，不表达O157侧链，这是通过用特定的多克隆O157抗血清凝集，通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分离的脂多糖提取物进行银染以及用多克隆O157进行的Western免疫印迹来评估的特异性抗血清。当通过Giemsa染色和明视野显微镜检查时，O157阴性突变体和亲本菌株均显示出对HEp-2细胞的局部粘附。此外，当通过粘附细菌CFU的定量评估时，与亲本菌株相比，两个O157阴性突变体均显示出对HEp-2细胞的粘附增强。当贴壁细菌和HEp-2细胞用异硫氰酸荧光素标记的鬼笔环肽染色时，亲本株CL-8和两个突变体均产生荧光灶。透射电子显微镜证实菌株CL-8和OO7阴性突变体附着于HEp-2细胞上并使其消失。这些发现表明，缺乏O157多糖重复序列的突变体在体外表现出对组织培养细胞的粘附，并且不需要O157多糖重复序列来产生附着和消失的病变。

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