Vibrio alginolyticus mutants resistant to phenamil, a specific inhibitor of the sodium-driven flagellar motor

Kojima, Seiji; Atsumi, Tatsuo; Muramoto, Kazumasa; Kudo, Satoshi; Kawagishi, Ikuro; Homma, Michio

doi:10.1006/jmbi.1996.0732

Cited by 42 publications

(49 citation statements)

References 31 publications

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“…In order to verify that the three-step process is an intrinsic swimming pattern adopted by V. alginolyticus, we also studied two additional strains, VIO5 (Pof þ Laf − ) and 138-2 (wild type) (18). The bacterium 138-2 is capable of expressing both polar and lateral flagella.…”

Section: The Bacterial Flagellum Is Actively Involved In Randomizing mentioning

confidence: 99%

Bacterial flagellum as a propeller and as a rudder for efficient chemotaxis

Xie

Altindal²,

Chattopadhyay³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

263

292

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We investigate swimming and chemotactic behaviors of the polarly flagellated marine bacteria Vibrio alginolyticus in an aqueous medium. Our observations show that V. alginolyticus execute a cyclic, three-step (forward, reverse, and flick) swimming pattern that is distinctively different from the run-tumble pattern adopted by Escherichia coli. Specifically, the bacterium backtracks its forward swimming path when the motor reverses. However, upon resuming forward swimming, the flagellum flicks and a new swimming direction is selected at random. In a chemically homogeneous medium (no attractant or repellent), the consecutive forward t f and backward t b swimming times are uncorrelated. Interestingly, although t f and t b are not distributed in a Poissonian fashion, their difference Δt ¼ jt f − t b j is. Near a point source of attractant, on the other hand, t f and t b are found to be strongly correlated, and Δt obeys a bimodal distribution. These observations indicate that V. alginolyticus exploit the time-reversal symmetry of forward and backward swimming by using the time difference to regulate their chemotactic behavior. By adopting the three-step cycle, cells of V. alginolyticus are able to quickly respond to a chemical gradient as well as to localize near a point source of attractant.bacterial chemotaxis | bacterial swimming pattern E nteric bacteria, such as Escherichia coli, swim by rotating a set of flagella that forms a bundle when the flagellar motors turn in the counterclockwise (CCW) direction (1-3). The bundle falls apart when one or more motors turns in the clockwise (CW) direction, and the bacterium tumbles (4). A new swimming direction is selected upon resuming the CCW rotation of the flagellar motors. By modulating the CCW and CW intervals according to external chemical cues, the cells are able to migrate toward attractants or away from repellents (5, 6).Certain bacterial species possess a single polar flagellum with a bidirectional motor similar to E. coli. Being single polarly flagellated, low Reynolds number (Re) hydrodynamics dictates that, aside from random thermal motions, the bacterium can only backtrack its trajectory when the motor reverses. This raises an interesting question concerning how this type of cells performs chemotaxis. Studies of motility patterns of single polarly flagellated bacteria Pseudomonas citronellolis showed that the bacteria change the swimming direction by a brief reversal between two long runs. From the published trajectories (7), each reversal typically results in a small change in cell orientation, and thus several reversals appear to be necessary for a significant change in the swimming direction. Backtracking was also observed in a number of single flagellated marine bacteria such as Shewanella putrefaciens, Pseudoalteromonas haloplanktis, and Vibrio alginolyticus, which execute the so-called run-reverse steps when following attractants released from porous beads and from algae (8-10). A pioneering experiment in V. alginolyticus revealed that the timereversal s...

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Section: The Bacterial Flagellum Is Actively Involved In Randomizing mentioning

confidence: 99%

Bacterial flagellum as a propeller and as a rudder for efficient chemotaxis

Xie

Altindal²,

Chattopadhyay³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

263

292

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“…Imae demonstrated that sodium channel-blocking drugs, such as amiloride, specifically inhibited sodium-driven motility and could be used to probe motor function (170). Mutants were isolated that could swim in the presence of the sodium channel-blocking drug (92). Currently, an understanding of the architecture of the sodium-type flagellar motor is being developed by studying V. alginolyticus, V. cholerae, and V. parahaemolyticus (reviewed in reference 202).…”

Section: Sodium Channel-blocking Drugs Specifically Interfere With Pomentioning

confidence: 99%

Polar Flagellar Motility of the Vibrionaceae

McCarter

2001

Microbiol Mol Biol Rev

308

356

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Polar flagella of Vibrio species can rotate at speeds as high as 100,000 rpm and effectively propel the bacteria in liquid as fast as 60 μm/s. The sodium motive force powers rotation of the filament, which acts as a propeller. The filament is complex, composed of multiple subunits, and sheathed by an extension of the cell outer membrane. The regulatory circuitry controlling expression of the polar flagellar genes of members of the Vibrionaceae is different from the peritrichous system of enteric bacteria or the polar system of Caulobacter crescentus. The scheme of gene control is also pertinent to other members of the gamma purple bacteria, in particular to Pseudomonas species. This review uses the framework of the polar flagellar system of Vibrio parahaemolyticus to provide a synthesis of what is known about polar motility systems of the Vibrionaceae. In addition to its propulsive role, the single polar flagellum of V. parahaemolyticus is believed to act as a tactile sensor controlling surface-induced gene expression. Under conditions that impede rotation of the polar flagellum, an alternate, lateral flagellar motility system is induced that enables movement through viscous environments and over surfaces. Although the dual flagellar systems possess no shared structural components and although distinct type III secretion systems direct the simultaneous placement and assembly of polar and lateral organelles, movement is coordinated by shared chemotaxis machinery

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“…The fluctuations induced by phenamil are explained by changes in the functional force-generating unit number in a motor and are attributed to a low dissociation rate of the inhibitor from the force-generating unit. Motility mutants resistant to phenamil, which is thought to interact with the sodium channel of the flagellar motor, were isolated, and the phenotype was named Mpa r for motility resistant to phena-mil (26). The Mpa r mutations have recently been mapped to PomA or PomB at the residue near the cytoplasmic ends of the putative transmembrane segments (25).…”

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Cysteine-Scanning Mutagenesis of the Periplasmic Loop Regions of PomA, a Putative Channel Component of the Sodium-Driven Flagellar Motor in Vibrio alginolyticus

et al. 2000

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The sodium-driven motor consists of the products of at least four genes, pomA, pomB, motX, and motY, in Vibrio alginolyticus. PomA and PomB, which are homologous to the MotA and MotB components of protondriven motors, have four transmembrane segments and one transmembrane segment, respectively, and are thought to form an ion channel. In PomA, two periplasmic loops were predicted at positions 21 to 36 between membrane segments 1 and 2 (loop 1-2 ) and at positions 167 to 180 between membrane segments 3 and 4 (loop 3-4 ). To characterize the two periplasmic loop regions, which may have a role as an ion entrance for the channel, we carried out cysteine-scanning mutagenesis. The T186 residue in the fourth transmembrane segment and the D71, D148, and D202 residues in the predicted cytoplasmic portion of PomA were also replaced with Cys. Only two mutations, M179C and T186C, conferred a nonmotile phenotype. Many mutations in the periplasmic loops and all of the cytoplasmic mutations did not abolish motility, though the five successive substitutions from M169C to K173C of loop 3-4 impaired motility. In some mutants that retained substantial motility, motility was inhibited by the thiol-modifying reagents dithionitrobenzoic acid and Nethylmaleimide. The profiles of inhibition by the reagents were consistent with the membrane topology predicted from the hydrophobicity profiles. Furthermore, from the profiles of labeling by biotin maleimide, we predicted more directly the membrane topology of loop 3-4 . None of the loop 1-2 residues were labeled, suggesting that the environments around the two loops are very different. A few of the mutations were characterized further. The structure and function of the loop regions are discussed.

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Vibrio alginolyticus mutants resistant to phenamil, a specific inhibitor of the sodium-driven flagellar motor

Cited by 42 publications

References 31 publications

Bacterial flagellum as a propeller and as a rudder for efficient chemotaxis

Bacterial flagellum as a propeller and as a rudder for efficient chemotaxis

Polar Flagellar Motility of the Vibrionaceae

Cysteine-Scanning Mutagenesis of the Periplasmic Loop Regions of PomA, a Putative Channel Component of the Sodium-Driven Flagellar Motor in Vibrio alginolyticus

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