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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 C. jejuni with immobilised SBA. (A) C. jejuni 11168H interaction with SBA lectin is concentration dependent. The figures below the bars indicate the numbers of cells per well. (B) Effect of different concentrations of soluble SBA lectin on binding of C. jejuni 11168H. (C) Effect of different concentrations of GalNAc on binding of C. jejuni 11168H.
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Figure 1: Interaction of C. jejuni with immobilised SBA. (A) C. jejuni 11168H interaction with SBA lectin is concentration dependent. The figures below the bars indicate the numbers of cells per well. (B) Effect of different concentrations of soluble SBA lectin on binding of C. jejuni 11168H. (C) Effect of different concentrations of GalNAc on binding of C. jejuni 11168H.

Mentions: Incubation of a suspension of C. jejuni 11168H cells with immobilised SBA resulted in bacterial attachment (Figure 1A). This binding was found to be specific as demonstrated by inhibitory effects by both GalNAc and a soluble form of SBA in a dose-dependent manner. The inhibitory effect was detectable with as low concentration of SBA lectin as 0.1 μM (Figure 1B). GalNAc also showed an inhibitory effect at concentrations over 10 μM (Figure 1C). Moreover, the bound cells could be detached in the presence of a soluble form of lectin or GalNAc (Figure 2). Further confirmation of specific binding was obtained by treatment of bacterial cells with an exoglycosidase. Removal of a terminal GalNAc resulted in a remarkable reduction of the ability of bacterial cells to attach (Figure 3).


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 C. jejuni with immobilised SBA. (A) C. jejuni 11168H interaction with SBA lectin is concentration dependent. The figures below the bars indicate the numbers of cells per well. (B) Effect of different concentrations of soluble SBA lectin on binding of C. jejuni 11168H. (C) Effect of different concentrations of GalNAc on binding of C. jejuni 11168H.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Interaction of C. jejuni with immobilised SBA. (A) C. jejuni 11168H interaction with SBA lectin is concentration dependent. The figures below the bars indicate the numbers of cells per well. (B) Effect of different concentrations of soluble SBA lectin on binding of C. jejuni 11168H. (C) Effect of different concentrations of GalNAc on binding of C. jejuni 11168H.
Mentions: Incubation of a suspension of C. jejuni 11168H cells with immobilised SBA resulted in bacterial attachment (Figure 1A). This binding was found to be specific as demonstrated by inhibitory effects by both GalNAc and a soluble form of SBA in a dose-dependent manner. The inhibitory effect was detectable with as low concentration of SBA lectin as 0.1 μM (Figure 1B). GalNAc also showed an inhibitory effect at concentrations over 10 μM (Figure 1C). Moreover, the bound cells could be detached in the presence of a soluble form of lectin or GalNAc (Figure 2). Further confirmation of specific binding was obtained by treatment of bacterial cells with an exoglycosidase. Removal of a terminal GalNAc resulted in a remarkable reduction of the ability of bacterial cells to attach (Figure 3).

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