title: Exopolysaccharide production in biofilms: substratum activation of alginate gene expression by Pseudomonas aeruginosa.
abstract: Reporter gene technology was employed to detect the activity of an alginate promoter of Pseudomonas aeruginosa when the organism was grown as a biofilm on a Teflon mesh substratum and as planktonic cells in liquid medium. Alginate biosynthetic activity was determined with a mucoid cell line derived from a cystic fibrosis isolate and containing an alginate algC promoter fused to a lacZ reporter gene. Reporter activity was demonstrated with chromogenic and fluorogenic substrates for beta-galactosidase. Expression of algC was shown to be upregulated in biofilm cells compared with planktonic cells in liquid medium. Gene up-expression correlated with alginate biosynthesis as measured by Fourier transform infrared spectroscopy, uronic acid accumulation, and alginate-specific enzyme-linked immunosorbent assay. The algC promoter was shown to have maximum activity in planktonic cultures during the late lag and early log phases of the cell growth cycle. During a time course experiment, biofilm algC activity exceeded planktonic activity except during the period immediately following inoculation into fresh medium. In continuous-culture experiments, conversion of lacZ substrate was demonstrated microscopically in individual cells by epifluorescence microscopy.
authors: Center for Interfacial Microbial Process Engineering, Montana State University, Bozeman 59717.
authors: D G
authors: DG
authors: Davies
authors: A M
authors: AM
authors: Chakrabarty
authors: G G
authors: GG
authors: Geesey
mesh_terms: D000464:Alginates / Q000378:metabolism*; D001422:Bacterial Adhesion / Q000502:physiology; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D005798:Genes, Bacterial / Q000502:physiology; D008856:Microscopy, Fluorescence; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D011138:Polytetrafluoroethylene; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics; D013997:Time Factors
chemical_list: D000464:Alginates; D011135:Polysaccharides, Bacterial; D011138:Polytetrafluoroethylene