Iron acquisition in Vibrio cholerae

Abstract

Vibrio cholerae, the causative agent of cholera, has an absolute requirement for iron and must obtain this element in the human host as well as in its varied environmental niches. It has multiple systems for iron acquisition, including the TonB-dependent transport of heme, the endogenous siderophore vibriobactin and several siderophores that are produced by other microorganisms. There is also a Feo system for the transport of ferrous iron and an ABC transporter, Fbp, which transports ferric iron. There appears to be at least one additional high affinity iron transport system that has not yet been identified. In iron replete conditions, iron acquisition genes are repressed by Fur. Fur also represses the synthesis of a small, regulatory RNA, RyhB, which negatively regulates genes for iron-containing proteins involved in the tricarboxylic acid cycle and respiration as well as genes for motility and chemotaxis. The redundancy in iron transport systems has made it more difficult to determine the role of individual systems in vivo and in vitro, but it may reflect the overall importance of iron in the growth and survival of V. cholerae.

Physiological responses of the scleractinian coral Pocillopora damicornis to bacterial stress from Vibrio coralliilyticus

“…Ferritins, which can sequester iron, play dual roles in detoxification and iron storage (Arosio et al, 2009;Arosio and Levi, 2010), and the selenium-binding protein covalently binds selenium (Bansal et al, 1989;Jeong et al, 2009). Interestingly, iron appears to be essential for bacterial growth (Doherty, 2007), especially for Vibrio species (Wright et al, 1981;Tolmasky and Crosa, 1991;Wyckoff et al, 2007), and selenium is a trace element crucial for the survival of all living organisms through the formation of selenocysteine, a modified amino acid largely implicated in antioxidant defense (e.g. glutathione peroxidase, thioredoxin reductase) (Burk et al, 2003;Stadtman, 1996).…”

An in vivo expression technology screen for Vibrio cholerae genes expressed in human volunteers

“…Deletion of VC0201 ( fhuC), an iron-regulated gene that encodes an ABC transporter component for hydroxamate compounds like ferrichrome (9, 11), led to a 22-fold attenuation in the mouse ( Table 2). This finding implicates hydroxamate compounds as an important iron source during infection, an important finding because the iron sources used by V. cholerae in the host are not clear (12). Deletion of VC2705, which encodes a sodium symporter, led to a 14-fold attenuation (3).…”

A mutant in one of two exbD loci of a TonB system in Flavobacterium psychrophilum shows attenuated virulence and confers protection against cold water disease

“…However, knowledge on the mechanism of pathogenesis is still limited. Iron is an essential element for the majority of bacterial life, and therefore microorganisms have developed multiple iron-acquisition systems (Wyckoff et al, 2007). Due to the reduced availability of iron in host tissues, the ability to obtain iron in vivo by micro-organisms is considered an important factor in pathogenicity (Payne, 1993;Wooldridge & Williams, 1993;Braun, 1995).…”