title: Effects of chronic sub-lethal oxidative stress on biofilm formation by Azotobacter vinelandii.
abstract: This work showed that perturbations of the physiological steady-state level of reactive oxygen species (ROS) affected biofilm genesis and the characteristics of the model bacterium Azotobacter vinelandii. To get a continuous endogenous source of ROS, a strain exposed to chronic sub-lethal oxidative stress was deprived of the gene coding for the antioxidant rhodanese-like protein RhdA (MV474). In this study MV474 biofilm showed (i) a seven-fold higher growth rate, (ii) induction of catalase and alkyl-hydroxyl-peroxidase enzymes, (iii) higher average thicknesses due to increased production of a polysaccharide-rich extracellular matrix and (iv) less susceptibility to hydrogen peroxide than the wild-type strain (UW136). MV474 showed increased swimming and swarming activity and the swarming colonies experienced a higher level of oxidative stress compared to UW136. A continuous exogenous source of ROS increased biofilm formation in UW136. Overall, chronic sub-lethal oxidative events promoted sessile behavior in A. vinelandii.
authors.affiliation: Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente, Università degli Studi di Milano, via Celoria 2, Milano, 20133, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Villa
authors.forename: William
authors.initials: W
authors.lastname: Remelli
authors.forename: Fabio
authors.initials: F
authors.lastname: Forlani
authors.forename: Michela
authors.initials: M
authors.lastname: Gambino
authors.forename: Paolo
authors.initials: P
authors.lastname: Landini
authors.forename: Francesca
authors.initials: F
authors.lastname: Cappitelli
mesh_terms: D016948:Azotobacter vinelandii / Q000502:physiology*; D018441:Biofilms; D002465:Cell Movement; D002723:Chlorobenzoates; D005109:Extracellular Matrix / Q000378:metabolism; D006861:Hydrogen Peroxide; D018384:Oxidative Stress; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D002723:Chlorobenzoates; D011135:Polysaccharides, Bacterial; D017382:Reactive Oxygen Species; C060415:2-chlorobenzoic acid; D006861:Hydrogen Peroxide