Na+ and flagella-dependent swimming of alkaliphilic Bacillus pseudofirmus OF4:: a basis for poor motility at low pH and enhancement in viscous media in an "up-motile" variant
Na+ and flagella-dependent swimming of alkaliphilic Bacillus pseudofirmus OF4:: a basis for poor motility at low pH and enhancement in viscous media in an "up-motile" variant
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DOI：
10.1007/s00203-006-0192-7
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发表时间：
2007-03-01
影响因子：
2.8
通讯作者：
Ito, Masahiro
中科院分区：
文献类型：
--
作者：
Fujinami, Shun;Terahara, Naoya;Ito, Masahiro
极端嗜碱芽孢杆菌的鞭毛运动完全依赖于Na+。在pH值<类似于8.0时观察到很少的运动性。在这里，我们研究的鞭毛/细胞的数量作为生长pH值的函数在兼性嗜碱芽孢杆菌pseudofirmus OF 4和衍生物选择增加运动在软琼脂平板上。鞭毛产生的两种菌株在生长过程中的pH范围从7.5至10.3。鞭毛/细胞和鞭毛蛋白水平的细胞的数量并不强烈依赖于生长pH值在此范围内，在任何一个菌株，虽然这两个参数较高的向上运动的菌株。游泳速度的测定表明，在pH < 8时，10 mM Na+没有运动性，但在pH 7时，在高得多的Na+浓度下有显著的运动性。在pH 8-10范围内，当Na+浓度达到230 mM时，游动速度随Na+浓度的增加而增加，在pH 10时游动速度最快。向上运动的菌株的运动性大大增加，相对于野生型的软琼脂在碱性pH值，但不是在液体中，除了当加入聚乙烯吡咯烷酮，以增加粘度。具有增加的鞭毛/细胞的向上运动表型可以支持束形成，其在具有特定挑战的条件的子集下特别增强运动性。
Flagella-based motility of extremely alkaliphilic Bacillus species is completely dependent upon Na+. Little motility is observed at pH values < similar to 8.0. Here we examine the number of flagella/cell as a function of growth pH in the facultative alkaliphile Bacillus pseudofirmus OF4 and a derivative selected for increased motility on soft agar plates. Flagella were produced by both strains during growth in a pH range from 7.5 to 10.3. The number of flagella/cell and flagellin levels of cells were not strongly dependent on growth pH over this range in either strain although both of these parameters were higher in the up-motile strain. Assays of the swimming speed indicated no motility at pH < 8 with 10 mM Na+, but significant motility at pH 7 at much higher Na+ concentrations. At pH 8-10, the swimming speed increased with the increase of Na+ concentration up to 230 mM, with fastest swimming at pH 10. Motility of the up-motile strain was greatly increased relative to wild-type on soft agar at alkaline pH but not in liquid except when polyvinylpyrrolidone was added to increase viscosity. The up-motile phenotype, with increased flagella/cell may support bundle formation that particularly enhances motility under a subset of conditions with specific challenges.