Bk. Gudmundsdottir, COMPARISON OF EXTRACELLULAR PROTEASES PRODUCED BY AEROMONAS-SALMONICIDA STRAINS, ISOLATED FROM VARIOUS FISH SPECIES, Journal of Applied Bacteriology, 80(1), 1996, pp. 105-113
Extracellular products (ECPs) of five typical and 25 atypical Aeromona
s salmonicida isolates from various fish species and geographical loca
tions were analysed by substrate specificity, inhibition of proteolyti
c activity and substrate SDS-PAGE. The type strains of Aer. salmonicid
a subsp. salmonicida and Aer. salmonicida subsp. achromogenes were inc
luded for comparison. The results indicated that the strains formed si
x protease groups. The proteases produced by the two type strains were
of a different nature. All the typical strains belonged to one group
and showed proteolytic activities comparable to P1 and P2 proteases. T
hree atypical (oxidase-negative) strains secreted a protease comparabl
e to P1. With the exception of these three, all strains produced metal
lo-gelatinases. A metallo-caseinase (AsaP1) was detected in the ECP of
subsp, achromogenes type strain and 10 of the atypical strains. A num
ber of proteolytic components with different apparent molecular weight
s (AMWs) were identified. These include caseinases with AMWs of > 100,
80, 60 and 30 kDa and gelatinolytic components with different AMWs, i
ncluding some with AMW higher than P1 and lower than P2. The protease
production of the isolates was not found to be host specific.