Varga John J, Nguyen Van, O'Brien David K, Rodgers Katherine, Walker Richard A, Melville Stephen B
Department of Biological Sciences, 2119 Derring Hall, Virginia Tech, Blacksburg, VA 24061, USA.
Mol Microbiol. 2006 Nov;62(3):680-94. doi: 10.1111/j.1365-2958.2006.05414.x. Epub 2006 Sep 25.
Bacteria can swim in liquid media by flagellar rotation and can move on surfaces via gliding or twitching motility. One type of gliding motility involves the extension, attachment and retraction of type IV pili (TFP), which pull the bacterium towards the site of attachment. TFP-dependent gliding motility has been seen in many Gram-negative bacteria but not in Gram-positive bacteria. Recently, the genome sequences of three strains of Clostridium perfringens have been completed and we identified gene products involved in producing TFP in each strain. Here we show that C. perfringens produces TFP and moves with an unusual form of gliding motility involving groups of densely packed cells moving away from the edge of a colony in curvilinear flares. Mutations introduced into the pilT and pilC genes of C. perfringens abolished motility and surface localization of TFP. Genes encoding TFP are also found in the genomes of all nine Clostridium species sequenced thus far and we demonstrated that Clostridium beijerinckii can move via gliding motility. It has recently been proposed that the Clostridia are the oldest Eubacterial class and the ubiquity of TFP in this class suggests that a Clostridia-like ancestor possessed TFP, which evolved into the forms seen in many Gram-negative species.
细菌可通过鞭毛旋转在液体培养基中游动，并可通过滑行或颤动运动在表面移动。一种类型的滑行运动涉及IV型菌毛（TFP）的伸展、附着和缩回，这些菌毛将细菌拉向附着位点。依赖TFP的滑行运动已在许多革兰氏阴性菌中观察到，但在革兰氏阳性菌中未观察到。最近，产气荚膜梭菌的三株菌株的基因组序列已完成，我们在每个菌株中鉴定出参与产生TFP的基因产物。在这里，我们表明产气荚膜梭菌产生TFP，并以一种不寻常的滑行运动形式移动，即密集排列的细胞群以曲线状耀斑从菌落边缘移开。引入产气荚膜梭菌pilT和pilC基因的突变消除了运动性和TFP的表面定位。到目前为止，在所有已测序的9种梭菌属物种的基因组中也发现了编码TFP的基因，我们证明拜氏梭菌可以通过滑行运动移动。最近有人提出，梭菌是最古老的真细菌类群，TFP在该类群中的普遍存在表明，类似梭菌的祖先拥有TFP，它进化成了许多革兰氏阴性菌中所见的形式。
