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Virulence of metalloproteases produced by Vibrio species on Pacific oyster Crassostrea gigas larvae.
|Title||Virulence of metalloproteases produced by Vibrio species on Pacific oyster Crassostrea gigas larvae.|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Authors||Hasegawa H, Gharaibeh DN, Lind EJ, Häse CC|
|Journal||Diseases of aquatic organisms|
|Date Published||2009 Jun 10|
|Keywords||Aging, Animals, Bacillus, Crassostrea, Culture Media, Larva, Metalloproteases, Pseudomonas aeruginosa, Substrate Specificity, Vibrio|
Vibrio tubiashii, a pathogen of shellfish larvae and juveniles, produces several extracellular products. Here, we document that culture supernatants of several marine Vibrio species showed toxicity to oyster larvae. Treatment of these supernatants with EDTA not only severely diminished proteolytic activities, but also dramatically reduced toxicity to the larvae. Culture supernatants of metalloprotease-deficient mutants of V. tubiashii, V. cholerae, and V. splendidus were impaired in their ability to cause larval death compared to the wild type strains. Culture supernatants of Pseudomonas aeruginosa, known to contain several secreted proteases, showed virtually no toxicity to oyster larvae. Purified V. tubiashii protease A (VtpA), but not the prototype metalloprotease, thermolysin from Bacillus thermoproteolyticus, was highly toxic to the larvae. In addition, toxicity of purified VtpA was much greater for 6-d-old oyster larvae than for 16-d-old larvae. Together, these results indicated that culture supernatants of a variety of Vibrio species are highly toxic to oyster larvae and that the production of a metalloprotease is required for this effect. We propose that there are, as yet uncharacterized, specific substrates contained in larval tissue that are degraded by VtpA as well as certain homologous metalloproteases produced by other marine Vibrio species which, in turn, may contribute to vibriosis.
|Alternate Journal||Dis. Aquat. Org.|