Roles of type IV pili, flagellum-mediated motility and extracellular DNA in the formation of mature multicellular structures in Pseudomonas aeruginosa biofilms
Roles of type IV pili, flagellum-mediated motility and extracellular DNA in the formation of mature multicellular structures in Pseudomonas aeruginosa biofilms
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DOI：
10.1111/j.1462-2920.2008.01658.x
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发表时间：
2008-09-01
影响因子：
5.1
通讯作者：
Tolker-Nielsen, Tim
中科院分区：
文献类型：
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作者：
Barken, Kim B.;Pamp, Suenje J.;Tolker-Nielsen, Tim
当铜绿假单胞菌在实验室流动室中作为生物膜生长时，可以在帽和柄部分形成由不同亚群组成的蘑菇状多细胞结构。我们先前已经提出了证据，证明铜绿假单胞菌生物膜中蘑菇形结构的帽部分的形成经由细菌迁移发生并且取决于IV型皮利（Mol Microbiol 50：61-68）。在本研究中，我们研究了参与形成这种多细胞亚结构的其他因素。虽然pilA突变体，缺乏IV型皮利，是缺乏蘑菇帽形成，pilH和chpA突变体，这是在IV型菌毛连接的化学感受系统失活，只显示帽形成的轻微缺陷。相反，fliM突变体，这是非鞭毛，和cheY突变体，这是在鞭毛连接的趋化系统失活，在很大程度上缺乏帽形成。实验涉及DNA酶处理的发展中的生物膜提供的证据表明，细胞外DNA在帽形成中发挥作用。此外，缺乏群体感应控制的DNA释放的突变体形成小菌落，野生型细菌不能形成帽。这些结果构成证据表明，IV型皮利，鞭毛介导的运动性和群体感应控制的DNA释放参与铜绿假单胞菌生物膜中成熟多细胞结构的形成。
When grown as a biofilm in laboratory flow chambers Pseudomonas aeruginosa can develop mushroom-shaped multicellular structures consisting of distinct subpopulations in the cap and stalk portions. We have previously presented evidence that formation of the cap portion of the mushroom-shaped structures in P. aeruginosa biofilms occurs via bacterial migration and depends on type IV pili (Mol Microbiol 50: 61-68). In the present study we examine additional factors involved in the formation of this multicellular substructure. While pilA mutants, lacking type IV pili, are deficient in mushroom cap formation, pilH and chpA mutants, which are inactivated in the type IV pili-linked chemosensory system, showed only minor defects in cap formation. On the contrary, fliM mutants, which are non-flagellated, and cheY mutants, which are inactivated in the flagellum-linked chemotaxis system, were largely deficient in cap formation. Experiments involving DNase treatment of developing biofilms provided evidence that extracellular DNA plays a role in cap formation. Moreover, mutants that are deficient in quorum sensing-controlled DNA release formed microcolonies upon which wild-type bacteria could not form caps. These results constitute evidence that type IV pili, flagellum-mediated motility and quorum sensing-controlled DNA release are involved in the formation of mature multicellular structures in P. aeruginosa biofilms.