title: L-Tryptophan prevents Escherichia coli biofilm formation and triggers biofilm degradation.
abstract: The effect of deletion of trp operon and tna operon on the Escherichia coli biofilm formation was investigated in order to elucidate the role of L-tryptophan metabolism in biofilm formation. trp operon deletion mutants ΔtrpC, ΔtrpD and ΔtrpE deficient in L-tryptophan biosynthesis showed higher biofilm formation. In addition, ΔtnaC with increased L-tryptophan degradation activity showed higher biofilm formation. On the contrary, ΔtnaA deletion mutant which lost L-tryptophan degradation activity showed low biofilm formation. From these results, it was suggested that decrease of intracellular L-tryptophan level induced biofilm formation and increase of L-tryptophan repressed biofilm formation. So the effect of the addition of L-tryptophan to the medium on the E. coli biofilm formation was investigated. L-Tryptophan addition at starting culture decreased biofilm formation and furthermore L-tryptophan addition after 16 h culture induced the degradation of preformed biofilm. From the above results, it was suggested that maintenance of high intracellular L-tryptophan concentration prevents E. coli biofilm formation and elevation of intracellular L-tryptophan concentration triggers degradation of matured biofilm.
authors.affiliation: Department of Food Science and Technology, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi 252-0880, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Shimazaki
authors.forename: Soichi
authors.initials: S
authors.lastname: Furukawa
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Ogihara
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Morinaga
mesh_terms: D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D009876:Operon / Q000235:genetics / Q000502:physiology*; D014364:Tryptophan / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D014364:Tryptophan