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A negative effect of Campylobacter capsule on bacterial interaction with an analogue of a host cell receptor.

Rubinchik S, Seddon AM, Karlyshev AV - BMC Microbiol. (2014)

Bottom Line: We demonstrate that the production of capsule reduces bacterial attachment, and that the genes involved in capsule and PEB3 adhesin biosynthesis are differentially regulated.The results suggest an interfering effect of capsule on bacterial attachment.The results will assist in better understanding of the mechanism of pathogenesis of C. jejuni in general and the role of capsule in the process in particular.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Life Sciences, Kingston University, Faculty of Science, Engineering and Computing, Penrhyn Road, Kingston-upon Thames KT1 2EE, UK. a.karlyshev@kingston.ac.uk.

ABSTRACT

Background: Campylobacter jejuni (C. jejuni) is the leading causative agent of bacterial gastrointestinal infections. The rise of antibiotic resistant forms of this pathogen necessitates the development of novel intervention strategies. One approach is the design of drugs preventing bacterial attachment to host cells. Although some putative C. jejuni adhesins have been identified, the molecular mechanisms of their interaction with host cells and their role in pathogenesis remain to be elucidated. C. jejuni adhesion may also be modulated by a bacterial capsule. However, the role of this structure in adhesion was not clear due to conflicting results published by different research groups. The aim of this study was to clarify the role of capsule in bacterial interaction with host cells by using an in vitro model of adhesion and an analogue of a host cell receptor.

Results: In this study, we developed an in vitro bacterial adhesion assay, which was validated using various tests, including competitive inhibition studies, exoglycosydase treatment and site-directed mutagenesis. We demonstrate that PEB3 is one of the cell surface glycoproteins required for bacterial interaction with an analogue of a host cell receptor. In contrast, JlpA glycoprotein adhesin is not required for such interaction. We demonstrate that the production of capsule reduces bacterial attachment, and that the genes involved in capsule and PEB3 adhesin biosynthesis are differentially regulated.

Conclusions: In this study we report an in vitro model for the investigation of bacterial interaction with analogs of host cell receptors. The results suggest an interfering effect of capsule on bacterial attachment. In addition, using a liquid culture, we demonstrate differential expression of a gene involved in capsule production (kpsM) and a gene encoding a glycoprotein adhesin (peb3). Further studies are required in order to establish if these genes are also differentially regulated during the infection process. The results will assist in better understanding of the mechanism of pathogenesis of C. jejuni in general and the role of capsule in the process in particular.

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Interaction of E. coli cells, containing C. jejuni glycosylation gene cluster, with SBA lectin. (A) Confocal microscopy of E. coli XL2/pPGL1 after treatment with fluorescently labelled SBA. No fluorescence was observed for E. coli XL2 control (data are not shown). (B) Attachment of E. coli XL2/pPGL1 to immobilized SBA lectin (1) is inhibited by GalNAc at 5 mM (2). No binding of the recipient strain E. coli XL2 was detected (3).
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Figure 4: Interaction of E. coli cells, containing C. jejuni glycosylation gene cluster, with SBA lectin. (A) Confocal microscopy of E. coli XL2/pPGL1 after treatment with fluorescently labelled SBA. No fluorescence was observed for E. coli XL2 control (data are not shown). (B) Attachment of E. coli XL2/pPGL1 to immobilized SBA lectin (1) is inhibited by GalNAc at 5 mM (2). No binding of the recipient strain E. coli XL2 was detected (3).

Mentions: In order to further confirm that the developed model of attachment is specific and is based on the surface-located GalNAc moieties, we repeated the binding experiments using E. coli cells carrying the entire N-linked protein glycosylation apparatus (pgl gene cluster) of C. jejuni[24]. Due to the absence of glycosylation acceptor proteins in strain E. coli XL2/pPGL1, the pgl system was found to be able to glycosylate the bacterial lipo-polysaccharide, resulting in exposure of GalNAc residues on the cell surface [24] (Figure 4A). The results confirmed that E. coli XL2/pPGL1 cells are capable of binding to immobilized SBA lectin in a GalNAc dependent fashion (Figure 4B).


A negative effect of Campylobacter capsule on bacterial interaction with an analogue of a host cell receptor.

Rubinchik S, Seddon AM, Karlyshev AV - BMC Microbiol. (2014)

Interaction of E. coli cells, containing C. jejuni glycosylation gene cluster, with SBA lectin. (A) Confocal microscopy of E. coli XL2/pPGL1 after treatment with fluorescently labelled SBA. No fluorescence was observed for E. coli XL2 control (data are not shown). (B) Attachment of E. coli XL2/pPGL1 to immobilized SBA lectin (1) is inhibited by GalNAc at 5 mM (2). No binding of the recipient strain E. coli XL2 was detected (3).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4061916&req=5

Figure 4: Interaction of E. coli cells, containing C. jejuni glycosylation gene cluster, with SBA lectin. (A) Confocal microscopy of E. coli XL2/pPGL1 after treatment with fluorescently labelled SBA. No fluorescence was observed for E. coli XL2 control (data are not shown). (B) Attachment of E. coli XL2/pPGL1 to immobilized SBA lectin (1) is inhibited by GalNAc at 5 mM (2). No binding of the recipient strain E. coli XL2 was detected (3).
Mentions: In order to further confirm that the developed model of attachment is specific and is based on the surface-located GalNAc moieties, we repeated the binding experiments using E. coli cells carrying the entire N-linked protein glycosylation apparatus (pgl gene cluster) of C. jejuni[24]. Due to the absence of glycosylation acceptor proteins in strain E. coli XL2/pPGL1, the pgl system was found to be able to glycosylate the bacterial lipo-polysaccharide, resulting in exposure of GalNAc residues on the cell surface [24] (Figure 4A). The results confirmed that E. coli XL2/pPGL1 cells are capable of binding to immobilized SBA lectin in a GalNAc dependent fashion (Figure 4B).

Bottom Line: We demonstrate that the production of capsule reduces bacterial attachment, and that the genes involved in capsule and PEB3 adhesin biosynthesis are differentially regulated.The results suggest an interfering effect of capsule on bacterial attachment.The results will assist in better understanding of the mechanism of pathogenesis of C. jejuni in general and the role of capsule in the process in particular.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Life Sciences, Kingston University, Faculty of Science, Engineering and Computing, Penrhyn Road, Kingston-upon Thames KT1 2EE, UK. a.karlyshev@kingston.ac.uk.

ABSTRACT

Background: Campylobacter jejuni (C. jejuni) is the leading causative agent of bacterial gastrointestinal infections. The rise of antibiotic resistant forms of this pathogen necessitates the development of novel intervention strategies. One approach is the design of drugs preventing bacterial attachment to host cells. Although some putative C. jejuni adhesins have been identified, the molecular mechanisms of their interaction with host cells and their role in pathogenesis remain to be elucidated. C. jejuni adhesion may also be modulated by a bacterial capsule. However, the role of this structure in adhesion was not clear due to conflicting results published by different research groups. The aim of this study was to clarify the role of capsule in bacterial interaction with host cells by using an in vitro model of adhesion and an analogue of a host cell receptor.

Results: In this study, we developed an in vitro bacterial adhesion assay, which was validated using various tests, including competitive inhibition studies, exoglycosydase treatment and site-directed mutagenesis. We demonstrate that PEB3 is one of the cell surface glycoproteins required for bacterial interaction with an analogue of a host cell receptor. In contrast, JlpA glycoprotein adhesin is not required for such interaction. We demonstrate that the production of capsule reduces bacterial attachment, and that the genes involved in capsule and PEB3 adhesin biosynthesis are differentially regulated.

Conclusions: In this study we report an in vitro model for the investigation of bacterial interaction with analogs of host cell receptors. The results suggest an interfering effect of capsule on bacterial attachment. In addition, using a liquid culture, we demonstrate differential expression of a gene involved in capsule production (kpsM) and a gene encoding a glycoprotein adhesin (peb3). Further studies are required in order to establish if these genes are also differentially regulated during the infection process. The results will assist in better understanding of the mechanism of pathogenesis of C. jejuni in general and the role of capsule in the process in particular.

Show MeSH
Related in: MedlinePlus