Motility and chemotaxis in alkaliphilic Bacillus species

• Published in: Future microbiology Vol. 4; no. 9; pp. 1137 - 1149
• Main Authors: Fujinami, Shun, Terahara, Naoya, Krulwich, Terry Ann, Ito, Masahiro
• Format: Journal Article
• Language: English
• Published: England Future Medicine Ltd 01.11.2009
• Subjects: Bacillus - physiology; Bacteria; Bacteriology; Cation Transport Proteins - metabolism; Chemotaxis; E coli; Flagella - metabolism; Hydrogen-Ion Concentration; Microbiology; Molecular Motor Proteins - metabolism; Proteins; Sodium - metabolism; Studies
• ISSN: 1746-0913; 1746-0921
• DOI: 10.2217/FMB.09.76

Alkaliphilic Bacillus species grow at pH values up to approximately 11. Motile alkaliphilic Bacillus use electrochemical gradients of Na(+) (sodium-motive force) to power ion-coupled, flagella-mediated motility as opposed to the electrochemical gradients of H(+) (proton-motive force) used by most neutralophilic bacteria. Membrane-embedded stators of bacterial flagella contain ion channels through which either H(+) or Na(+) flow to energize flagellar rotation. Stators of the major H(+)-coupled type, MotAB, are distinguishable from Na(+)-coupled stators, PomAB of marine bacteria and MotPS of alkaliphilic Bacillus. Dual ion-coupling capacity is found in neutralophilic Bacillus strains with both MotAB and MotPS. There is also a MotAB variant that uses both coupling ions, switching as a function of pH. Chemotaxis of alkaliphilic Bacillus depends upon flagellar motility but also requires a distinct voltage-gated NaChBac-type channel. The two alkaliphile Na(+) channels provide new vistas on the diverse adaptations of sensory responses in bacteria.