Variation of extracellular proteases produced by Vibrio vulnificus clinical isolates: genetic diversity of the metalloprotease gene (vvp), and serine protease secretion by vvp-negative strains.
Vibrio vulnificus is a causative agent of septicemia or wound infection in human and eel; however, the genetic variation between human and eel isolates has been reported. In the present study, the difference in the vvp gene encoding a tissue-damaging metalloprotease was investigated. The gene of strain E86 from a diseased eel (type B vvp) was 95.2% identical with that of strain L-180 from human blood (type A vvp). PCR using oligonucleotide primers designed to differentiate two types of the gene showed that eel avirulent strains (9 isolates) commonly carry type A vvp, whereas eel virulent strains (18 isolates) revealed significant genetic variation. The vvp genes from 12 strains including strain E86 were placed on type B while those from 3 strains were on type A. Other strains were found to be vvp-negative, but PAGE and amino acid sequencing analysis showed that they secreted a serine protease (VVA0302) instead of the metalloprotease. This protease is an orthologue of a toxic protease from Vibrio parahaemolyticus, a human pathogen causing wound infection as well as gastroenteritis. These findings suggest that, in addition to metalloprotease, the extracellular serine protease may contribute to pathogenicity of V. vulnificus.
Wang
Jiyou
J
Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima-Naka, Okayama 700-8530, Japan.
Sasaki
Tomoko
T
Maehara
Yoko
Y
Nakao
Hiroshi
H
Tsuchiya
Tomofusa
T
Miyoshi
Shin-Ichi
S
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D004524:Eels / Q000382:microbiology; D005110:Extracellular Space / Q000201:enzymology*; D005393:Fish Diseases / Q000382:microbiology; D015870:Gene Expression; D014644:Genetic Variation; D006801:Humans; D007564:Japan; D045726:Metalloproteases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D021381:Protein Transport; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013030:Spain; D014735:Vibrio Infections / Q000382:microbiology* / Q000662:veterinary*; D041261:Vibrio vulnificus / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification
D001426:Bacterial Proteins; D045726:Metalloproteases; D012697:Serine Endopeptidases