title: Urea hydrolysis and suppressed production of thermostable direct hemolysin (TDH) by Vibrio parahaemolyticus associated with presence of TDH-related hemolysin genes.
abstract: A total of 18 strains of V. parahaemolyticus isolated from patients of past food poisoning cases occurring in Kanagawa Prefecture, Japan, were assayed for presence of the thermostable direct hemolysin (TDH) gene and the TDH-related hemolysin (TRH) genes (trh 1 and trh 2) with specific reference to their ability to hydrolyze urea and TDH production. A polymerase chain reaction assay revealed that all urea-hydrolyzing strains (9 strains) carried either trh 1 gene or trh 2 gene. The strains carrying the trh genes as well as the tdh gene produced TDH less by a factor of 4 to 16 than those carrying only the tdh gene, suggesting the expression of the tdh gene was suppressed by the presence of trh gene through a mechanism yet to be defined.
authors.affiliation: Department of Bacteriology and Pathology, Kanagawa Prefectural Public Health Laboratories, 1-1-1 Nakao, Asahi-ku, Yokohama-shi, Kanagawa, 241, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Okitsu
authors.forename: R
authors.initials: R
authors.lastname: Osawa
authors.forename: S
authors.initials: S
authors.lastname: Pornruangwong
authors.forename: S
authors.initials: S
authors.lastname: Yamai
mesh_terms: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D005517:Foodborne Diseases / Q000382:microbiology; D005798:Genes, Bacterial; D005838:Genotype; D006460:Hemolysin Proteins / Q000096:biosynthesis* / Q000235:genetics*; D006801:Humans; D006868:Hydrolysis; D007841:Latex Fixation Tests; D010641:Phenotype; D014508:Urea / Q000378:metabolism*; D014736:Vibrio parahaemolyticus / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D017931:DNA Primers; D006460:Hemolysin Proteins; C088609:thermostable direct hemolysin-related hemolysin protein, Vibrio parahaemolyticus; C068489:thermostable direct hemolysin; D014508:Urea