Defined deletion mutants demonstrate that the major secreted toxins are not essential for the virulence of Aeromonas salmonicida.

ABSTRACT: The importance of the two major extracellular enzymes of Aeromonas salmonicida, glycerophospholipid: cholesterol acyltransferase (GCAT) and a serine protease (AspA), to the pathology and mortality of salmonid fish with furunculosis had been indicated in toxicity studies. In this study, the genes encoding GCAT (satA) and AspA (aspA) have been cloned and mutagenized by marker replacement of internal deletions, and the constructs have been used for the creation of isogenic satA and aspA mutants of A. salmonicida. A pSUP202 derivative (pSUP202sac) carrying the sacRB genes was constructed to facilitate the selection of mutants. The requirement of serine protease for processing of pro-GCAT was demonstrated. Processing involved the removal of a short internal fragment. Surprisingly, pathogenicity

SUBMITTER: Vipond R 

PROVIDER: S-EPMC108155 | biostudies-literature | 1998 May

REPOSITORIES: biostudies-literature