title: Chemotactic responses to an attractant and a repellent by the polar and lateral flagellar systems of Vibrio alginolyticus.
abstract: Chemotactic responses in Vibrio alginolyticus, which has lateral and polar flagellar systems in one cell, were investigated. A lateral-flagella-defective (Pof+ Laf-) mutant, which has only a polar flagellum, usually swam forward by the pushing action of its flagellum and occasionally changed direction by backward swimming. When the repellent phenol was added, Pof+ Laf- cells moved frequently forward and backward (tumbling state). The tumbling was derived from the frequent changing between counter-clockwise and clockwise (CW) rotation of the flagellar motor, as was confirmed by the tethered-cell method. Furthermore, we found that the tumbling cells did not adapt to the phenol stimulus. When the attractant serine was added, the phenol-treated cells ceased tumbling and swam smoothly, adapting to the attractant stimulus after several minutes. We isolated chemotaxis-defective (Che-) mutants from the Pof+ Laf- mutant; the tumbling mutants were not isolated. One interesting mutant swam backwards continuously, with its flagellum leading the cell and its flagellar motor rotating CW continuously. A polar-flagella-defective mutant (Pof- Laf+) stopped swimming after phenol addition and then recovered swimming ability within 10 min, indicating that lateral flagella can adapt to the repellent stimulus. This may represent a functional difference between the two flagellar systems in Vibrio cells, and between the chemotaxis systems affecting the two types of flagella.
authors.affiliation: Department of Molecular Biology, Faculty of Science, Nagoya University, Japan. g44416a@nucc.cc.nagoya-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Homma
authors.forename: H
authors.initials: H
authors.lastname: Oota
authors.forename: S
authors.initials: S
authors.lastname: Kojima
authors.forename: I
authors.initials: I
authors.lastname: Kawagishi
authors.forename: Y
authors.initials: Y
authors.lastname: Imae
mesh_terms: D000222:Adaptation, Physiological; D002630:Chemotactic Factors / Q000494:pharmacology*; D002633:Chemotaxis / Q000187:drug effects; D005407:Flagella / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D010636:Phenols / Q000494:pharmacology; D012694:Serine / Q000494:pharmacology; D014733:Vibrio / Q000235:genetics / Q000502:physiology*
chemical_list: D002630:Chemotactic Factors; D010636:Phenols; D012694:Serine