Aims:  To clone, sequence and characterize the genetic organization of urease genes within urease‐positive thermophilic Campylobacter (UPTC). Methods and Results:  An approx. 5·1‐kbp region encoding a urease gene operon was identified, when recombinant plasmid DNAs from a genomic DNA library of a Japanese isolate (CF89‐12) of UPTC were analysed. Conclusions:  Six closely spaced and putative open reading frames (ORFs) for ureA, ureB, ureE, ureF, ureG and ureH were detected. ATG codons initiated each ORF of the UPTC urease operon except for ureB and ureH, which commenced with the most probable TTG codon. Overlaps were detected between ureA and ureB and also between ureB and ureE. Probable ribosome‐binding sites and a putative ρ‐independent transcriptional termination region were identified. Two putative promoter structures, consisting of consensus sequences at the −35 like and −10 regions were also identified. Significance and Impact of the Study:  Construction of a neighbour‐joining tree based on the nucleotide sequence data of urease genes indicated that UPTC formed a cluster with some Helicobacter organisms separate from the other urease‐producing bacteria, suggesting a commonly shared ancestry between UPTC and Helicobacter urease genes.

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A Vibrio vulnificus hemolysin (VVH) was purified by two steps of hydrophobic column chromatography on Phenyl-Sepharose HP. The first chromatography was carried out at pH 6.0. In this pH condition, VVH efficiently bound to the column, but the hemolysin fraction eluted was accompanied with colored substance(s). To eliminate this colored substance, the second chromatography was carried out at pH 9.8 in the presence of 1% 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS), a zwitterionic detergent. Homogeneity of the hemolysin thus obtained was shown by polyacrylamide gel electrophoresis. The specific activity increased 33, 600 times and the yield was 35%. The method is simple and useful to supply enough VVH for study of the role of the hemolysin in the infection by V. vulnificus or on the mechanism of action of the hemolysin.

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