title: Differential expression of a sodium-phosphate cotransporter among Vibrio vulnificus strains.
abstract: Vibrio vulnificus is an estuarine bacterium with pathogenic potential. Its three known biotypes differ in host distribution. We have found the nptA gene for a sodium-phosphate cotransporter, which is rare in bacteria, in each biotype. nptA transcript abundance differed significantly among biotypes, leading to the hypothesis that transcript levels differ under environmental conditions associated with estuarine and host environments. nptA transcript abundance was assessed in V. vulnificus biotypes 1 (C and E genotypes), 2 and 3 strains under varied salinity, phosphate concentration, and pH. Differences in transcript abundance separated strains into two groups. Type C and biotype 3 strains formed Group 1, while type E and biotype 2 strains formed Group 2. Group 2 strains had significantly greater nptA RNA transcript abundance than Group 1. Transcript abundance in the two groups also responded differently to pH and salinity, suggesting differential regulation of nptA in response to environmental conditions. Comparison of the deduced amino acid sequences of NptA among strains resulted in strain grouping similar to that based on transcript abundance. Variation in transcript abundance between groups may affect the ability of V. vulnificus strains to colonize hosts and/or to compete as free-living bacteria in various habitats.
authors.affiliation: Department of Integrative Biology, University of South Florida, 4202 E. Fowler Avenue, SCA 110, Tampa, FL, 33620, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Staley
authors.forename: Valerie J
authors.initials: VJ
authors.lastname: Harwood
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015373:Bacterial Typing Techniques; D004777:Environment; D005838:Genotype; D006863:Hydrogen-Ion Concentration; D010710:Phosphates / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054712:Salinity; D012623:Seawater / Q000737:chemistry; D017422:Sequence Analysis, DNA; D050608:Sodium-Phosphate Cotransporter Proteins / Q000235:genetics / Q000378:metabolism*; D041261:Vibrio vulnificus / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D010710:Phosphates; D050608:Sodium-Phosphate Cotransporter Proteins