Molecular Studies on Iron Acquisition by Non-Escherichia coli Species

Payne, Shelley M.; Lawlor, Kathleen M.

doi:10.1016/b978-0-12-370390-3.50014-7

Cited by 10 publications

(10 citation statements)

References 45 publications

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“…The ability to acquire this essential element under iron-limited conditions present within the host, therefore, is considered to be critical to the virulence and survival of a number of bacterial pathogens (Payne & Lawlor, 1990). As a response to this nutritional restriction bacteria have evolved highly efficient systems for sequestering iron (Briat, 1992 ;Wooldridge & Williams, 1993).…”

Section: Introductionmentioning

confidence: 99%

Enterochelin acquisition in Campylobacter coli: characterization of components of a binding-protein-dependent transport system

Richardson

Park

1995

Microbiology

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Siderophore-mediated iron uptake systems play a central role in the pathogenesis of infection for many bacterial pathogens. Campylobacter species are not thought to produce siderophores, yet they are able to utilize both ferrichrome and enterochelin as sources of iron. Part of an operon named ceuBCDE, encoding components of a periplasmic binding-protein-dependent transport (PBT) system for the uptake of a ferric siderophore from Campylobacter coli, was cloned directly into Escherichia coli using a plasmid rescue technique. Phenotypic and genetic analyses of this system showed it to comprise two hydrophobic integral membrane proteins, CeuB (35.5 kDa) and CeuC (348 kDa), which may form the cytoplasmic membrane permease, an ATP-binding protein, CeuD (288 kDa), and a periplasmic substrate-binding protein, CeuE (345 kDa). In vivo labelling studies using [3H]palmitate demonstrated that CeuE, the periplasmic binding protein, is expressed as a lipoprotein in C. coli, which is unusual for a Gram-negative PBT system. Mutants of C. coli, defective in components of the transport mechanism, were severely impaired in the ability to utilize enterochelin as an iron source suggesting that this siderophore is a substrate for the transport system. This is the first molecular characterization of a PBT system in Campylobacter species.

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Section: Introductionmentioning

confidence: 99%

Enterochelin acquisition in Campylobacter coli: characterization of components of a binding-protein-dependent transport system

Richardson

Park

1995

Microbiology

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“…Among the best studied of these adhesive structures are pili (fimbriae) and outer membrane proteins (OMPs, or porins), both of which project into the bacterium's environment. The regulation, structure, and specificity of fimbriae and OMPs have been best described in certain pathogenic bacterial species (23,29,35), including the human intestinal pathogen Vibrio cholerae (2). In contrast, less is known about the mechanisms by which benign bacteria initiate specific, cooperative, and often obligate associations that can persist throughout the life of the host.…”

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Vibrio fischeriOuter Membrane Protein OmpU Plays a Role in Normal Symbiotic Colonization

et al. 2001

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The nascent light-emitting organ of newly hatched juveniles of the Hawaiian sepiolid squid Euprymna scolopes is specifically colonized by cells of Vibrio fischeri that are obtained from the ambient seawater. The mechanisms that promote this specific, cooperative colonization are likely to require a number of bacterial and host-derived factors and activities, only some of which have been described to date. A characteristic of many host-pathogen associations is the presence of bacterial mechanisms that allow attachment to specific tissues. These mechanisms have been well characterized and often involve bacterial fimbriae or outer membrane proteins (OMPs) that act as adhesins, the expression of which has been linked to virulence regulators such as ToxR in Vibrio cholerae. Analogous or even homologous mechanisms are probably operative in the initiation and persistence of cooperative bacterial associations, although considerably less is known about them. We report the presence in V. fischeri of ompU, a gene encoding a 32.5-kDa protein homolog of two other OMPs, OmpU of V. cholerae (50.8% amino acid sequence identity) and OmpL of Photobacterium profundum (45.5% identity). A null mutation introduced into the V. fischeri ompU resulted in the loss of an OMP with an estimated molecular mass of about 34 kDa; genetic complementation of the mutant strain with a DNA fragment containing only the ompU gene restored the production of this protein. The expression of the V. fischeri OmpU was not significantly affected by either (i) iron or phosphate limitation or (ii) a mutation that renders V. fischeri defective in the synthesis of a homolog of the OMP-regulatory protein ToxR. The ompU mutant grew normally in complex nutrient media but was more susceptible to growth inhibition in the presence of either anionic detergents or the antimicrobial peptide protamine sulfate. Interestingly, colonization experiments showed that the ompU null mutant initiated a symbiotic association with juvenile light organ tissue with only about 60% of the effectiveness of the parent strain. When colonization did occur, it proceeded more slowly and resulted in an approximately fourfoldsmaller bacterial population. Surprisingly, there was no evidence that in a mixed infection with its parent, the ompU-defective strain had a competitive disadvantage, suggesting that the presence of the parent strain provided a shared compensatory activity. Thus, the OmpU protein appears to play a role in the normal process by which V. fischeri initiates its colonization of the nascent light organ of juvenile squids.

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“…By analogy with other species producing hemolysins, these could play a role in pathogenesis (1,11,16,24). It has been suggested that some hemolysins are also involved in iron acquisition, a critical requirement for successful colonization by many enteropathogenic organisms (25). The nature of iron acquisition systems and their contribution to the virulence of Campylobacter species is not yet defined.…”

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Molecular characterization of a Campylobacter jejuni lipoprotein with homology to periplasmic siderophore-binding proteins

Park

Richardson

1995

J Bacteriol

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A genomic library of Campylobacter jejuni (NCTC 11351) was used to identify genes which could confer a hemolytic phenotype to Escherichia coli. Accordingly, when transformants were screened on blood plates, hemolytic colonies appeared at a frequency of 3 ؋ 10 ؊4. The gene conferring the hemolytic activity was identified by subcloning and was found to be responsible for the phenotype of all hemolytic transformants isolated. The open reading frame conferring this activity encodes a protein of 36,244 Da with a typical endopeptidase type II leader sequence. The protein is modified with palmitic acid when it is processed in E. coli, confirming that it is a typical lipoprotein. The deduced gene product of 329 amino acids has significant homology to the group of solute binding proteins from periplasmic-binding-protein-dependent transport systems for ferric siderophores, including the FatB protein from Vibrio anguillarium and the FhuD protein from Bacillus subtilis. In particular, the protein contained the signature sequence for siderophore-binding proteins, suggesting that the protein may be the siderophore-binding protein component of an iron acquisition system of C. jejuni.

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Molecular Studies on Iron Acquisition by Non-Escherichia coli Species

Cited by 10 publications

References 45 publications

Enterochelin acquisition in Campylobacter coli: characterization of components of a binding-protein-dependent transport system

Enterochelin acquisition in Campylobacter coli: characterization of components of a binding-protein-dependent transport system

Vibrio fischeriOuter Membrane Protein OmpU Plays a Role in Normal Symbiotic Colonization

Molecular characterization of a Campylobacter jejuni lipoprotein with homology to periplasmic siderophore-binding proteins

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