title: Escherichia coli exhibits negative chemotaxis in gradients of hydrogen peroxide, hypochlorite, and N-chlorotaurine: products of the respiratory burst of phagocytic cells.
abstract: Escherichia coli can respond to gradients of specific compounds, moving up gradients of attractants and down gradients of repellents. Stimulated phagocytic leukocytes produce H2O2, OCl-, and N-chlorotaurine in a response termed the respiratory burst. E. coli is actively repelled by these compounds. Catalase in the suspending medium eliminated the effect of H2O2. Repulsion by H2O2 could be demonstrated with 1 microM H2O2, which is far below the level that caused overt toxicity. Strains with defects in the biosynthesis of glutathione or lacking hydroperoxidases I and II retained this response to H2O2, and 2.0 mM CN- did not interfere with it. Mutants with defects in any one of the four known methyl-accepting chemotaxis proteins also retained the ability to respond to H2O2, but a "gutted" mutant that was deleted for all four methyl-accepting chemotaxis proteins, as well as for CheA, CheW, CheR, CheB, CheY, and CheZ, did not respond to H2O2. Hypochlorite and N-chlorotaurine were also strongly repellent. Chemotaxis down gradients of H2O2, OCl-, and N-chlorotaurine may contribute to the survival of commensal or pathogenic microorganisms.
authors.affiliation: Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: L
authors.initials: L
authors.lastname: Benov
authors.forename: I
authors.initials: I
authors.lastname: Fridovich
mesh_terms: D000818:Animals; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000378:metabolism; D006997:Hypochlorous Acid / Q000378:metabolism; D066298:In Vitro Techniques; D009154:Mutation; D010586:Phagocytes / Q000378:metabolism / Q000382:microbiology; D016897:Respiratory Burst; D013654:Taurine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D013654:Taurine; C043410:N-chlorotaurine; D006997:Hypochlorous Acid; D006861:Hydrogen Peroxide