title: Regulation of the alginate biosynthesis gene algC in Pseudomonas aeruginosa during biofilm development in continuous culture.
abstract: Reporter gene technology was used to observe the regulation of the alginate biosynthesis gene, algC in a mucoid strain of Pseudomonas aeruginosa in developing and mature biofilms in continuous culture on Teflon and glass substrata. The plasmid pNZ63, carrying an algC-lacZ transcriptional fusion, was shown to not be diluted in continuous culture over a period of 25 days in the absence of selection pressure. Biofilm cells under bulk phase steady-state conditions demonstrated fluctuations in algC expression over a 16-day period, but no trend of increased or decreased expression over the time interval was indicated. In vivo detection of algC up-expression in developing biofilms was performed with a fluorogenic substrate for the plasmid-borne lacZ gene product (beta-galactosidase) by using microscopy coupled with image analysis. By this technique, cells were tracked over time and analyzed for algC activity. During the initial stages of biofilm development, cells already attached to a glass surface for at least 15 min exhibited up-expression of algC, detectable as the development of whole-cell fluorescence. However, initial cell attachment to the substratum appeared to be independent of algC promoter activity. Furthermore, cells not exhibiting algC up-expression were shown to be less capable of remaining at a glass surface under flowing conditions than were cells in which algC up-expression was detected.
authors.affiliation: Center for Biofilm Engineering, Montana State University, Bozeman 59717.
authors.forename: D G
authors.initials: DG
authors.lastname: Davies
authors.forename: G G
authors.initials: GG
authors.lastname: Geesey
mesh_terms: D000464:Alginates / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D005798:Genes, Bacterial / Q000235:genetics; D017930:Genes, Reporter / Q000235:genetics; D005898:Glass; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D010733:Phosphoglucomutase / Q000235:genetics*; D017875:Phosphotransferases (Phosphomutases) / Q000235:genetics*; D011138:Polytetrafluoroethylene; D011401:Promoter Regions, Genetic / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000502:physiology*; D015854:Up-Regulation; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D011138:Polytetrafluoroethylene; D001616:beta-Galactosidase; D001618:beta-Lactamases; D017875:Phosphotransferases (Phosphomutases); D010733:Phosphoglucomutase; C052799:phosphomannomutase