Previous Article | Next Article ![]()
Infection and Immunity, October 2000, p. 5742-5748, Vol. 68, No. 10
Department of Bacterial Infections, Research
Institute for Microbial Diseases, Osaka University, Suita, Osaka
565-0871, Japan
Received 25 February 2000/Returned for modification 31 May
2000/Accepted 29 June 2000
We have demonstrated that possession of the gene for thermostable
direct hemolysin-related hemolysin (trh) coincides with the
presence of the urease gene among clinical Vibrio
parahaemolyticus strains and that the location of the two genes
are in close proximity on the chromosome. Here, we cloned and sequenced
the 15,754-bp DNA region containing the trh gene and the
gene cluster for urease production from the chromosome of clinical
V. parahaemolyticus (TH3996). We found 16 open reading
frames (ORFs) and a lower G+C content (41%) compared with the total
genome of this bacterium (46 to 47%). The ure cluster
consisted of eight genes, namely, ureDABCEFG and
ureR. ureR was located 5.2 kb upstream of the other seven
genes in the opposite direction. The genetic organization and sequences
of the ure genes resembled those found in Proteus mirabilis. Between ureR and the other ure
genes, there were five ORFs, which are homologous with the nickel
transport operon (nik) of Escherichia coli. We
disrupted each of the ureR, ureC, and nikD genes in TH3996 by homologous recombination and
analyzed the phenotype of the mutants. In the presence of urea these
mutant strains had dramatically less urease activity than the strain they were derived from. Disruption of ureR,
nikD, or ureC, however, had no effect on TRH
production. The DNA region containing the trh,
nik, and ure genes was found in only
trh-positive strains and not in Kanagawa
phenomenon-positive and environmental V. parahaemolyticus strains. At the end of the region, an insertion sequence-like element
existed. These results suggest that the DNA region was introduced into
V. parahaemolyticus in the past through a mechanism mediated by insertion sequences. This is the first reported case that
the genes for an ATP-binding cassette-type nickel transport system,
which may play a role in nickel transport through bacterial cytoplasmic
membrane, are located adjacent to the ure cluster on the
genome of an organism.
0019-9567/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Genetic Characterization of DNA Region Containing
the trh and ure Genes of Vibrio
parahaemolyticus

and
*
Corresponding author. Mailing address: Department of
Bacterial Infections, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan. Phone: 81-6-6879-8278. Fax: 81-6-6879-8277. E-mail:
iida{at}biken.osaka-u.ac.jp.
Present address: Department of Molecular Cell Biology, Institute of
Molecular Embryology and Genetics, Kumamoto University School of
Medicine, Kumamoto 862-0976, Japan.
Present address: Faculty of Health and Welfare Science, Okayama
Prefectural University, Soja, Okayama 719-1197, Japan.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»