ISSN:
1365-2761
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Medicine
Notes:
Abstract. The ability of A-layer-positi ve (A+) and A-layer-negative (A−) strains of Aeromonas salmonicida to utilize haem sources of iron under conditions of iron-restriction was evaluated. In a plate bioassay, only A+ strains of A. salmonicida were able to utilize haem from a variety of sources including haem, haemin, myoglobin, haemoglobin, haemoglobin- haptoglobin and haem-albumin complexes. Trypsin-digestion of whole cells abolished haem- binding, indicating that binding was cell-surface associated, involving a protein binding site or receptor. Competitive binding studies indicated that all haem compounds were bound by a common receptor, which was not iron-regulated and was associated with the presence of the 49-kDa A-layer protein. The ability of both typical A+ (siderophore-positive) and atypical A+ (siderophore-negative) strains to utilize haem indicated that the mechanism of haem utilization was not siderophore-mediated and that A. salmonicida possesses both siderophore-dependent and siderophore-independent mechanisms to overcome iron-restricted conditions encountered in vivo.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2761.1994.tb00232.x
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