Characterization of major virulent factor produced by pathogenic Vibrio harveyi
OMP (outmembrane protein), LPS (lipopolysaccharides), ECP (extracellular product) were extracted from Vibrio harveyi strain GYC1108-1, which was originally isolated from diseased great yellow croaker (Pseudosciaena crocea). The challenge tests showed that OMP and LPS had low lethal to P. crocea, and...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Zhejiang University Press
2011-03-01
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| Series: | 浙江大学学报. 农业与生命科学版 |
| Subjects: | |
| Online Access: | https://www.academax.com/doi/10.3785/j.issn.1008-9209.2011.02.004 |
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| Summary: | OMP (outmembrane protein), LPS (lipopolysaccharides), ECP (extracellular product) were extracted from Vibrio harveyi strain GYC1108-1, which was originally isolated from diseased great yellow croaker (Pseudosciaena crocea). The challenge tests showed that OMP and LPS had low lethal to P. crocea, and the protease in ECP was lethal to the fish with an LD<sub>50</sub> value of 3.5 μg protein·g<sup>-1</sup> body mass. The protease was therefore confirmed to be a major exotoxin of V. harveyi for P. crocea. The maximal activities of the protease were at pH 8.0 and 28 ℃. It was heat labile and had a molecular mass of about 55 ku estimated by SDS-PAGE. The purified protease from ECP was inhibited by iodoacetic acid, indicating that the enzyme was a cysteine protease. In addition, it was also completely inhibited by SDS and HgCl<sub>2</sub>, but partially inhibited by ZnCl<sub>2</sub> and PMSF (an inhibitor of serine protease) and not inhibited by CaCl<sub>2</sub>, CuCl<sub>2</sub> and MgCl<sub>2</sub>. However, activation of the enzyme activity was obtained with EDTA, EGTA (inhibitors of metalloprotease), DTT, L-cysteine and 2-mercaptoethanol. It was found that this protease could degrade several substrates, including casein, gelatin, lecithin, starch, Tween-80, urea and could not hemolyze blood cells of fish. Moreover, the protease had immunogenicity to fish. The band of 55 ku protease was presented on Western blotting pattern against fish anti-bacteria antiserum. Thus, the protease from ECP could be considered as protective antigen. |
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| ISSN: | 1008-9209 2097-5155 |