title: Influence of culture conditions on expression of the 40-kilodalton porin protein of Vibrio anguillarum serotype O2.
abstract: Vibrio anguillarum serotype O2 strains express a 40-kDa outer membrane porin protein. Immunoblot analysis revealed that antigenic determinants of the V. anguillarum O2 40-kDa porin were conserved within bacterial species of the genus Vibrio. The relative amounts of the V. anguillarum O2 40-kDa porin were enhanced by growth of V. anguillarum O2 in CM9 medium containing 5 to 10% sucrose or 0.1 to 0.5 M NaCl. In contrast, the levels of the porin were significantly reduced when cells were grown at 37 degrees C, and a novel 60-kDa protein was also observed. However, the osmolarity or ionic concentration of the growth medium did not influence expression of the 60-kDa protein. Growth in medium containing greater than 0.6 mM EDTA reduced production of the V. anguillarum O2 40-kDa porin and enhanced levels of a novel 19-kDa protein. Thus, expression of the V. anguillarum O2 40-kDa porin was osmoregulated and possibly coregulated by temperature. The N-terminal amino acid sequence of the V. anguillarum O2 40-kDa protein and the effect of environmental factors on the cellular levels of the porin suggested that the V. anguillarum O2 40-kDa porin was functionally similar to the OmpC porin of Escherichia coli. However, pore conductance assays revealed that the V. anguillarum O2 40-kDa porin was a general diffusion porin with a pore size in the range of that of the OmpF porin of E. coli.
authors.affiliation: Department of Microbiology, University of Guelph, Ontario, Canada.
authors.forename: M L
authors.initials: ML
authors.lastname: Davey
authors.forename: R E
authors.initials: RE
authors.lastname: Hancock
authors.forename: L M
authors.initials: LM
authors.lastname: Mutharia
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000502:physiology; D003470:Culture Media / Q000378:metabolism; D004492:Edetic Acid / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism; D000939:Epitopes / Q000235:genetics; D004926:Escherichia coli / Q000737:chemistry; D007477:Ions; D008969:Molecular Sequence Data; D019081:O Antigens / Q000276:immunology / Q000378:metabolism*; D009994:Osmolar Concentration; D018272:Porins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D014733:Vibrio / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D003470:Culture Media; D000939:Epitopes; D007477:Ions; D019081:O Antigens; D018272:Porins; D012965:Sodium Chloride; D013395:Sucrose; D004492:Edetic Acid; D010450:Endopeptidases