Extracellular proteolytic activity plays a central role in swarming motility in Bacillus subtilis
Extracellular proteolytic activity plays a central role in swarming motility in Bacillus subtilis
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DOI：
10.1128/jb.186.13.4159-4167.2004
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发表时间：
2004-07-01
影响因子：
3.2
通讯作者：
Sloma, A
中科院分区：
文献类型：
--
作者：
Connelly, MB;Young, GA;Sloma, A
天然分离的枯草芽孢杆菌表现出强大的多细胞行为，称为蜂群。蜂群是一种运动形式，其特点是细菌种群在一个表面上快速、协调地前进。作为一个集体细菌过程，蜂群通常与生物膜的形成有关，并与致病菌的毒力因子表达有关。虽然芽孢杆菌物种的群体表型已被充分记录，但对其分子机制的理解仍主要局限于革兰氏阴性菌。为了更好地了解芽孢杆菌属成员的群体是如何控制的，我们研究了一系列基因缺失对群体运动的影响。我们的分析表明，缺乏生产表面素和细胞外蛋白水解活性的菌株不会聚集或形成生物膜。虽然已知表面蛋白（一种脂蛋白表面活性剂）通过降低表面张力在蜂群运动中起作用，但这是第一个证明一般细胞外蛋白酶活性也具有重要功能的报告。这些结果不仅有助于确定引起蜂群迁移的因素，而且支持蜂群和生物膜形成可能具有重叠控制机制的观点。
Natural isolates of Bacillus subtilis exhibit a robust multicellular behavior known as swarming. A form of motility, swarming is characterized by a rapid, coordinated progression of a bacterial population across a surface. As a collective bacterial process, swarming is often associated with biofilm formation and has been linked to virulence factor expression in pathogenic bacteria. While the swarming phenotype has been well documented for Bacillus species, an understanding of the molecular mechanisms responsible remains largely isolated to gram-negative bacteria. To better understand how swarming is controlled in members of the genus Bacillus, we investigated the effect of a series of gene deletions on swarm motility. Our analysis revealed that a strain deficient for the production of surfactin and extracellular proteolytic activity did not swarm or form biofilm. While it is known that surfactin, a lipoprotein surfactant, functions in swarming motility by reducing surface tension, this is the first report demonstrating that general extracellular protease activity also has an important function. These results not only help to define the factors involved in eliciting swarm migration but support the idea that swarming and biofilm formation may have overlapping control mechanisms.