Josenhans C, Labigne A, Suerbaum S
Medizinische Mikrobiologie und Immunologie, Ruhr-Universität Bochum, Germany.
J Bacteriol. 1995 Jun;177(11):3010-20. doi: 10.1128/jb.177.11.3010-3020.1995.
Helicobacter mustelae causes chronic gastritis and ulcer disease in ferrets. It is therefore considered an important animal model of human Helicobacter pylori infection. High motility even in a viscous environment is one of the common virulence determinants of Helicobacter species. Their sheathed flagella contain a complex filament that is composed of two distinctly different flagellin subunits, FlaA and FlaB, that are coexpressed in different amounts. Here, we report the cloning and sequence determination of the flaA gene of H. mustelae NCTC12032 from a PCR amplification product. The FlaA protein has a calculated molecular mass of 53 kDa and is 73% homologous to the H. pylori FlaA subunit. Isogenic flaA and flaB mutants of H. mustelae F1 were constructed by means of reverse genetics. A method was established to generate double mutants (flaA flaB) of H. mustelae F1 as well as H. pylori N6. Genotypes, motility properties, and morphologies of the H. mustelae flagellin mutants were determined and compared with those of the H. pylori flaA and flaB mutants described previously. The flagellar organizations of the two Helicobacter species proved to be highly similar. When the flaB genes were disrupted, motility decreased by 30 to 40%. flaA mutants retained weak motility by comparison with strains that were devoid of both flagellin subunits. Weakly positive motility tests of the flaA mutants correlated with the existence of short truncated flagella. In H. mustelae, lateral as well as polar flagella were present in the truncated form. flaA flaB double mutants were completely nonmotile and lacked any form of flagella. These results show that the presence of both flagellin subunits is necessary for complete motility of Helicobacter species. The importance of this flagellar organization for the ability of the bacteria to colonize the gastric mucosa and to persist in the gastric mucus remains to be proven.
鼬螺杆菌可引起雪貂的慢性胃炎和溃疡病。因此，它被认为是人类幽门螺杆菌感染的重要动物模型。即使在粘性环境中仍具有高运动性是螺杆菌属常见的毒力决定因素之一。它们的鞘鞭毛含有一种复杂的丝状体，该丝状体由两个明显不同的鞭毛蛋白亚基FlaA和FlaB组成，这两个亚基以不同的量共表达。在此，我们报道了从PCR扩增产物中克隆和测定鼬螺杆菌NCTC12032的flaA基因序列。FlaA蛋白的计算分子量为53 kDa，与幽门螺杆菌FlaA亚基具有73%的同源性。通过反向遗传学构建了鼬螺杆菌F1的同基因flaA和flaB突变体。建立了一种方法来产生鼬螺杆菌F1以及幽门螺杆菌N6的双突变体（flaA flaB）。测定了鼬螺杆菌鞭毛蛋白突变体的基因型、运动特性和形态，并与先前描述的幽门螺杆菌flaA和flaB突变体进行了比较。结果证明这两种螺杆菌的鞭毛组织高度相似。当flaB基因被破坏时，运动性下降30%至40%。与缺乏两个鞭毛蛋白亚基的菌株相比，flaA突变体保留了较弱的运动性。flaA突变体的弱阳性运动性测试与短截鞭毛的存在相关。在鼬螺杆菌中，横向和极向鞭毛均以截短形式存在。flaA flaB双突变体完全不运动，且缺乏任何形式的鞭毛。这些结果表明，两种鞭毛蛋白亚基的存在对于螺杆菌属的完全运动性是必需的。这种鞭毛组织对于细菌在胃黏膜定植和在胃黏液中持续存在的能力的重要性仍有待证实。
