title: Repressed respiration of oral streptococci grown in biofilms.
abstract: The respiratory activities of oral streptococci grown in biofilms were found to be markedly repressed compared with those of cells from aerobic culture, or for Streptococcus mutans GS-5, even for those grown in static culture. Respiration rates generally reflected levels of NADH oxidase activities in cell extracts. Superoxide dismutase levels were somewhat reduced in biofilm cells. However, sensitivities to oxidative damage caused by H2O2, t-butylhydroperoxide, or 8-hydroxyquinoline were not greatly different for cells from suspension cultures and those from either intact or dispersed biofilms. The capacities of S. sanguis and S. gordonii to produce H2O2 also were markedly repressed by biofilm growth, and presumably this repression would affect the ecology of dental plaque by reducing oxidative stresses under crowded conditions.
authors.affiliation: Department of Microbiology & Immunology, Box 672, University of Rochester Medical Center, Rochester, NY 14642-8672, USA.
authors.forename: Phuong T M
authors.initials: PT
authors.lastname: Nguyen
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Abranches
authors.forename: Tuan-Nghia
authors.initials: TN
authors.lastname: Phan
authors.forename: Robert E
authors.initials: RE
authors.lastname: Marquis
mesh_terms: D000332:Aerobiosis; D018441:Biofilms / Q000254:growth & development*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009097:Multienzyme Complexes / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D010101:Oxygen Consumption; D015125:Oxyquinoline / Q000494:pharmacology; D019533:Streptococcus oralis / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
chemical_list: D009097:Multienzyme Complexes; D015125:Oxyquinoline; D020122:tert-Butylhydroperoxide; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases