The type IV bundle-forming pilus of enteropathogenic Escherichia coli undergoes dramatic alterations in structure associated with bacterial adherence, aggregation and dispersal
The type IV bundle-forming pilus of enteropathogenic Escherichia coli undergoes dramatic alterations in structure associated with bacterial adherence, aggregation and dispersal
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DOI：
10.1046/j.1365-2958.1999.01495.x
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发表时间：
1999-08-01
影响因子：
3.6
通讯作者：
Zorgani, AA
中科院分区：
文献类型：
--
作者：
Knutton, S;Shaw, RK;Zorgani, AA
BFP是由肠致病性大肠杆菌（EPEC）产生的质粒编码的IV型菌毛形成菌毛，最近已被证明与细菌的聚集和细菌从细菌小菌落的分散有关。在标准的3小时HEp-2细胞测定中，EPEC粘附在局部小菌落中; 6小时后，细菌小菌落不再存在，表明在EPEC粘附到培养的上皮细胞期间在体外发生细菌聚集和分散。为了研究BFP在EPEC聚集和分散中的作用，我们检测了E2348/69菌株的HEp-2细胞粘附，并通过免疫荧光和免疫电镜确定了E2348/69突变体。BFP最初表达为约40 nm直径的菌毛束，其促进细菌-细菌相互作用和小菌落形成。BFP随后经历了一个显着的改变，在结构组织与形成更长和更厚（直径约100 nm）的菌毛束，这经常横向聚集，形成更厚的束往往安排在一个松散的三维网络; EPEC分散从细菌小菌落与这种转变的BFP从薄到厚束。BFP从薄到厚束的细菌传播和转化没有发生与菌株E2348/69的bfpF突变体。它的结论是，BFP促进EPEC小菌落的形成和分散，分散阶段需要BfpF和分散与BFP束的结构的巨大变化。
BFP, a plasmid-encoded type IV bundle-forming pilus produced by enteropathogenic Escherichia coli (EPEC), has recently been shown to be associated with the aggregation of bacteria and dispersal of bacteria from bacterial microcolonies. In standard 3 h HEp-2 cell assays, EPEC adhere in localized microcolonies; after 6 h, bacterial microcolonies are no longer present, indicating that bacterial aggregation and dispersal occurs in vitro during EPEC adhesion to cultured epithelial cells. To examine the role of BFP in EPEC aggregation and dispersal, we examined HEp-2 cell adhesion of strain E2348/69 and defined E2348/69 mutants by immunofluorescence and immunoelectron microscopy. BFP was expressed initially as approximate to 40 nm diameter pilus bundles that promoted bacteria-bacteria interaction and microcolony formation. BFP subsequently underwent a striking alteration in structural organization with the formation of much longer and thicker (approximate to 100 nm diameter) pilus bundles, which frequently aggregated laterally to form even thicker bundles often arranged in a loose three-dimensional network; EPEC dispersal from bacterial microcolonies was associated with this transformation of BFP from thin to thick bundles. Bacterial dispersal and transformation of BFP from thin to thick bundles did not occur with a bfpF mutant of strain E2348/69. It is concluded that BFP promotes both the formation and the dispersal of EPEC microcolonies, that the dispersal phase requires BfpF and that dispersal is associated with dramatic alterations in the structure of BFP bundles.