Study on the relationship of protease production and luminescence in Vibrio harveyi.
OBJECTIVE
To demonstrate that Vibrio harveyi produces various types of toxins and how the production of those toxins is related with luminescence.


RESULTS
Luminescence and toxicity of eight V. harveyi were evaluated. We demonstrated that all V. harveyi emitting luminescence were isolated from marine organisms and also showed that they were highly pathogenic when compared with culture collection V. harveyi based on cytotoxic assay test. On the contrary, V. harveyi isolated from shrimp farm showed no luminescence but showed high pathogenicity based on toxicity test. The effect of protease inhibitors on pathogenicity and luminescence was also investigated. We demonstrated that light emission of pathogenic V. harveyi remarkably decreased after addition of protease inhibitor. Furthermore, extracellular proteins from cell-free culture supernatant of luminescent and nonluminescent V. harveyi were compared using SDS-PAGE analysis. Results showed that there were differences in molecular weight and amount of proteins.


CONCLUSIONS
Vibrio harveyi parasiting marine organisms have both luminescence and pathogenicity. Based on this study, luminescence and protease toxin activity in V. harveyi are related. Moreover, this paper clarified that V. harveyi produces various types of toxins.


CONCLUSIONS
The current study demonstrated that V. harveyi produces two kinds of toxins, haemolysin and protease toxin. It may be clear roots of V. harveyi toxin.
Nakayama
T
T
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
Nomura
N
N
Matsumura
M
M
D001426:Bacterial Proteins / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism*; D006460:Hemolysin Proteins; D049449:Luminescence; D008163:Luminescent Measurements; D011480:Protease Inhibitors / Q000494:pharmacology; D012623:Seawater; D018675:Toxicity Tests; D014118:Toxins, Biological / Q000378:metabolism; D014733:Vibrio / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D014774:Virulence; D014871:Water Microbiology
D001426:Bacterial Proteins; D006460:Hemolysin Proteins; D011480:Protease Inhibitors; D014118:Toxins, Biological; C073845:hemolysin, Vibrio; D010450:Endopeptidases