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Electrophoretic Detection of Proteases from Selected Strains of Flexibacter psychrophilus and Assessment of Their Variability
Author(s) -
Bertolini J. M.,
Wakabayashi H.,
Watral V. G.,
Whipple M. J.,
Rohovec J. S.
Publication year - 1994
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(1994)006<0224:edopfs>2.3.co;2
Subject(s) - proteases , biology , protease , infectivity , casein , virulence , microbiology and biotechnology , oncorhynchus , biochemistry , virus , virology , enzyme , fish <actinopterygii> , fishery , gene
The cell‐free extracellular products of a reference isolate of Flexibacter psychrophilus were analyzed by substrate gel electrophoresis (SDS‐PAGE), and proteases with apparent molecular masses (AMM) of 114 and 152 kiloDaltons (kDa), which had activity against both casein and gelatin, were identified. Proteases with AMMs from 32 to 86 kDa, which were active against gelatin but not casein, were also observed. Analysis of 28 additional isolates of F. psychrophilus indicated that the isolates formed four groups based on the presence or absence of certain proteases visualized by substrate SDS‐PAGE. Seven F. psychrophilus isolates from coho salmon Oncorhynchus kisutch and ayu Plecoglossus altivelis reared in Japan were included in the study. These isolates had protease patterns similar to isolates from the USA and could also be grouped. There was a correlation between protease group and the host from which the bacterium was isolated. Of the 29 isolates studied, all 11 group‐1 isolates were from coho salmon. The remaining six isolates from coho salmon were placed into protease group 2. The 12 isolates from species other than coho salmon belonged to protease group 2, 3, or 4. In vivo infectivity experiments with juvenile steelhead O. mykiss and coho salmon indicated some association between protease group and virulence.