Abstract：
The Legionella genus comprises more than 60 species. In particular, Legionella pneumophila is known to cause severe illnesses in humans. Legionellaceae are ubiquitous inhabitants of aquatic environments. Some Legionellaceae are motile and their motility is important to move around in habitats. Motility can be considered as a potential virulence factor as already shown for various human pathogens. The genes of the flagellar system, regulator and structural genes, are structured in hierarchical levels described as the flagellar regulon. Their expression is modulated by various environmental factors. For L. pneumophila it was shown that the expression of genes of the flagellar regulon is modulated by the actual growth phase and temperature. Especially, flagellated Legionella are known to express genes during the transmissive phase of growth that are involved in the expression of virulence traits. It has been demonstrated that the alternative sigma-28 factor is part of the link between virulence expression and motility. In the following review, the structure of the flagellar regulon of L. pneumophila is discussed and compared to other flagellar systems of different Legionella species. Recently, it has been described that Legionella micdadei and Legionella fallonii contain a second putative partial flagellar system. Hence, the report will focus on flagellated and non-flagellated Legionella strains, phylogenetic relationships, the role and function of the alternative sigma factor (FliA) and its anti-sigma-28 factor (FlgM).
摘要：
军团菌属包括60多种。特别是,已知嗜肺军团菌在人类中引起严重的疾病。军团科是水生环境中普遍存在的居民。一些军团菌科是能动的，它们的运动性对于在栖息地中移动很重要。运动性可以被认为是一种潜在的毒力因子，如已经显示的各种人类病原体。鞭毛系统的基因，调节基因和结构基因，被描述为鞭毛规则的分层结构。它们的表达受各种环境因素的调节。对于嗜肺乳杆菌，表明鞭毛调节子基因的表达受实际生长期和温度的调节。尤其是,已知鞭毛军团菌在生长的透射阶段表达与毒力性状表达有关的基因。已经证明，替代sigma-28因子是毒力表达和运动性之间联系的一部分。在下面的审查中，讨论了嗜肺乳杆菌鞭毛调节子的结构，并将其与不同军团菌的其他鞭毛系统进行了比较。最近,据描述，米达迪军团菌和费洛氏军团菌含有第二个推定的部分鞭毛系统。因此，该报告将重点关注鞭毛和非鞭毛军团菌菌株，系统发育关系，替代sigma因子（FliA）及其抗sigma-28因子（FlgM）的作用和功能。
