Ferric-reductase activities in Vibrio vulnificus biotypes 1 and 2

In this paper, the ferric-reductase activities of Vibrio vulnificus were in vestigated. This species comprises two biotypes pathogenic for humans and e els that are able to express different mechanisms for iron acquisition. All strains of both biotypes used in this study were able to reduce ferric cit rate, irrespective of the iron levels in the growth medium. Some variation in the degree of reduction was observed among the strains, with the highest values corresponding to one acapsulated environmental strain of biotype 1. When cell fractions were tested, only those from periplasm and cytoplasm s howed reductase activity whereas no activity was detected in membranes. Low temperatures inhibited these activities in both whole cells and cell fract ions. At least six bands with ferric-reductase activity were identified in all strains using native polyacrylamide gels. These data demonstrate that t he two biotypes of V. vulnificus produce similar ferric-reductases mainly l ocated in the periplasm and cytoplasm and these could be involved in iron a cquisition. (C) 1999 Published by Elsevier Science B.V. All rights reserved .