Kita-Tsukamoto K, Wada M, Yao K, Nishino T, Kogure K
Ocean Research Institute, University of Tokyo, Japan.
Can J Microbiol. 2004 May;50(5):369-74. doi: 10.1139/w04-021.
Bacterial cells in aquatic environments are able to reach or stay near nutrient patches by using motility. Motility is usually attained by rotating flagellar motors that are energized by electrochemical potential of H+ or Na+. In this paper, the ion specificity for flagellar rotation of two marine isolates Halomonas spp. strains US172 and US201 was investigated. Both isolates require sodium for growth and possess a respiratory-driven primary sodium pump. They are motile because of lateral flagella regardless of the presence of sodium ions. Their swimming speed under various concentrations of sodium ions with and without carbonylcyanide m-chlorophenylhydrazone, a proton conductor, and with and without phenamil, a specific inhibitor for the sodium-driven flagellar motors, was examined. The effect of carbonylcyanide m-chlorophenylhydrazone on the transmembrane proton gradient was also determined. Our results showed that the flagellar motors of the Halomonas strains were energized by both H+ and Na+ in one cell. The bimodal nature of Halomonas spp. motility with respect to the driving energy source may reflect ecophysiological versatility to adapt to a wide range of salt conditions of the marine environment.
水生环境中的细菌细胞能够通过运动到达或停留在营养斑块附近。运动通常是通过由H⁺或Na⁺的电化学势提供能量的旋转鞭毛马达来实现的。在本文中，研究了两株海洋分离株嗜盐单胞菌属菌株US172和US201鞭毛旋转的离子特异性。这两株分离株都需要钠来生长，并且拥有一个呼吸驱动的初级钠泵。无论钠离子是否存在，它们都因侧生鞭毛而具有运动能力。研究了它们在各种浓度的钠离子条件下，在有和没有质子导体羰基氰化物间氯苯腙以及有和没有钠驱动鞭毛马达的特异性抑制剂非那明的情况下的游动速度。还测定了羰基氰化物间氯苯腙对跨膜质子梯度的影响。我们的结果表明，嗜盐单胞菌菌株的鞭毛马达在一个细胞中由H⁺和Na⁺共同提供能量。嗜盐单胞菌属运动在驱动能源方面的双峰性质可能反映了其适应海洋环境广泛盐度条件的生态生理多样性。
