ISSN:
1365-2761
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Medicine
Notes:
Abstract The role of A-layer (A), protease (P) and haemolysin (H) as virulence factors of Aeromonas salmonicida, the aetiological agent of fish furunculosis, was a investigated using three strains of the bacterium. Strain MT004 lacked the A-Iayer (A−) and produced extracellular caseinase and gelatinase (P+) and haemolysin (T-lysin; H+). Strain MT028 was A−, P− and H−, and strain MT048 was A+, P+ and H−. The pathology and LD50 produced in rainbow trout by cells or extracellular products (ECP) of each strain were determined. The ECP was produced by two different methods where the protease and haemolytic activities differed in relative levels, or when the protease of MT004 ECP was inhibited by the serine protease inhibitor PMSF. The results indicate that the presence of A-layer is not essential, at least for a moderate degree of virulence; that in vitro production of extracellular proteases is not a requisite of virulent strains; that presence of protease and haemolysin in ECP can be correlated with the development of certain lesions and a rapid time to death but cannot be correlated with the lethal toxicity of the ECP. The authors conclude that an as-yet unrecognized component of ECP is responsible for killing fish.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2761.1988.tb01227.x
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