scholarly journals Point mutations in the major outer membrane protein drive hypervirulence of a rapidly expanding clone of Campylobacter jejuni

2016 ◽  
Vol 113 (38) ◽  
pp. 10690-10695 ◽  
Author(s):  
Zuowei Wu ◽  
Balamurugan Periaswamy ◽  
Orhan Sahin ◽  
Michael Yaeger ◽  
Paul Plummer ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Campylobacter Jejuni ◽  
Outer Membrane Protein ◽  
Animal Health ◽  
Major Outer Membrane Protein ◽  
Whole Genome Sequence ◽  
Bacterial Strains ◽  
Zoonotic Pathogen

Infections due to clonal expansion of highly virulent bacterial strains are clear and present threats to human and animal health. Association of genetic changes with disease is now a routine, but identification of causative mutations that enable disease remains difficult. Campylobacter jejuni is an important zoonotic pathogen transmitted to humans mainly via the foodborne route. C. jejuni typically colonizes the gut, but a hypervirulent and rapidly expanding clone of C. jejuni recently emerged, which is able to translocate across the intestinal tract, causing systemic infection and abortion in pregnant animals. The genetic basis responsible for this hypervirulence is unknown. Here, we developed a strategy, termed “directed genome evolution,” by using hybridization between abortifacient and nonabortifacient strains followed by selection in an animal disease model and whole-genome sequence analysis. This strategy successfully identified SNPs in porA, encoding the major outer membrane protein, are responsible for the hypervirulence. Defined mutagenesis verified that these mutations were both necessary and sufficient for causing abortion. Furthermore, sequence analysis identified porA as the gene with the top genome-wide signal of adaptive evolution using Fu’s Fs, a population genetic metric for recent population size changes, which is consistent with the recent expansion of clone “sheep abortion.” These results identify a key virulence factor in Campylobacter and a potential target for the control of this zoonotic pathogen. Furthermore, this study provides general, unbiased experimental and computational approaches that are broadly applicable for efficient elucidation of disease-causing mutations in bacterial pathogens.

scholarly journals A novel O -linked glycan modulates Campylobacter jejuni major outer membrane protein-mediated adhesion to human histo-blood group antigens and chicken colonization

Open Biology ◽  
2014 ◽  
Vol 4 (1) ◽  
pp. 130202 ◽  
Author(s):  
Jafar Mahdavi ◽  
Necmettin Pirinccioglu ◽  
Neil J. Oldfield ◽  
Elisabet Carlsohn ◽  
Jeroen Stoof ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Blood Group ◽  
Campylobacter Jejuni ◽  
Outer Membrane Protein ◽  
Ex Vivo ◽  
Binding Capacity ◽  
Major Outer Membrane Protein ◽  
Blood Group Antigens

Campylobacter jejuni is an important cause of human foodborne gastroenteritis; strategies to prevent infection are hampered by a poor understanding of the complex interactions between host and pathogen. Previous work showed that C. jejuni could bind human histo-blood group antigens (BgAgs) in vitro and that BgAgs could inhibit the binding of C. jejuni to human intestinal mucosa ex vivo. Here, the major flagella subunit protein (FlaA) and the major outer membrane protein (MOMP) were identified as BgAg-binding adhesins in C. jejuni NCTC11168 . Significantly, the MOMP was shown to be O- glycosylated at Thr 268 ; previously only flagellin proteins were known to be O- glycosylated in C. jejuni . Substitution of MOMP Thr 268 led to significantly reduced binding to BgAgs. The O- glycan moiety was characterized as Gal(β1–3)-GalNAc(β1–4)-GalNAc(β1–4)-GalNAcα1-Thr 268 ; modelling suggested that O- glycosylation has a notable effect on the conformation of MOMP and this modulates BgAg-binding capacity. Glycosylation of MOMP at Thr 268 promoted cell-to-cell binding, biofilm formation and adhesion to Caco-2 cells, and was required for the optimal colonization of chickens by C. jejuni , confirming the significance of this O- glycosylation in pathogenesis.

scholarly journals Production of a Monoclonal Antibody Specific for the Major Outer Membrane Protein of Campylobacter jejuni and Characterization of the Epitope

2007 ◽  
Vol 74 (3) ◽  
pp. 833-839 ◽  
Author(s):  
Hongliang Qian ◽  
Ervinna Pang ◽  
Qingyun Du ◽  
Jason Chang ◽  
Jin Dong ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Campylobacter Jejuni ◽  
Outer Membrane Protein ◽  
Protein Band ◽  
Major Outer Membrane Protein ◽  
Dot Blot ◽  
Detection And Identification ◽  
Dot Blot Assay

ABSTRACT Campylobacter species are important enteric pathogens causing disease in humans and animals. There is a lack of a good immunological test that can be used routinely to separate Campylobacter jejuni from other Campylobacter species. We produced monoclonal antibodies (MAbs) directed against the major outer membrane protein (MOMP) of C. jejuni using recombinant MOMP as the antigen. One MAb, designated MAb5C4 and of the immunoglobulin G1 isotype, was found to be potentially specific for C. jejuni. Dot blots demonstrated that MAb5C4 reacted with all 29 isolates of C. jejuni tested but did not react with 2 C. jejuni isolates, 26 other Campylobacter spp. isolates, and 19 non-Campylobacter isolates. Western blotting showed that MAb5C4 bound to a single protein band approximately 43 kDa in size, corresponding to the expected size of C. jejuni MOMP. The detection limit of MAb5C4 in a dot blot assay was determined to be about 5 × 103 bacteria. The epitope on the MOMP was mapped to a region six amino acids in length with the sequence 216GGQFNP221, which is 97% conserved among C. jejuni strains but divergent in other Campylobacter spp.; a GenBank search indicated that 95% of C. jejuni isolates will be able to be detected from non-Campylobacter spp. based on the highly specific and conserved region of the GGQFNP polypeptide. The epitope is predicted to be located in a region that is exposed to the periplasm. MAb5C4 is a potentially specific and sensitive MAb that can be used for the specific detection and identification of C. jejuni.

scholarly journals Recombinant PorA, the Major Outer Membrane Protein of Campylobacter jejuni, Provides Heterologous Protection in an Adult Mouse Intestinal Colonization Model

2010 ◽  
Vol 17 (11) ◽  
pp. 1666-1671 ◽  
Author(s):  
Anjum Islam ◽  
Raj Raghupathy ◽  
M. John Albert
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Campylobacter Jejuni ◽  
Outer Membrane Protein ◽  
Lavage Fluid ◽  
Major Outer Membrane Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Food Borne ◽  
Colonization Model ◽  
O 19

ABSTRACT Immunity against Campylobacter jejuni, a major food-borne pathogen causing diarrhea, is largely serotype specific. The major outer membrane protein (MOMP) of C. jejuni, PorA, is a common antigen with the potential to provide broad protection. Adult BALB/c mice were orally immunized with a recombinant glutathione S-transferase (GST) fused to PorA prepared from Campylobacter jejuni C31 (O:6,7) (GST-PorA) combined with a modified heat-labile enterotoxin of Escherichia coli as an adjuvant and later orally challenged with C31 strain or three heterologous strains: 48 (O:19), 75 (O:3), and 111 (O:1,44). Protection from colonization with the challenge organism was studied by fecal screening daily for 9 days. Serum and intestinal lavage fluid antibodies against the vaccine and Sarkosyl-purified MOMP from C31 were measured by using an enzyme-linked immunosorbent assay. The vaccine produced robust antibody responses against both antigens in serum and secretion. Since strain C31 was a poor colonizer, homologous protection could not be studied. The protective efficacies of heterologous strains were 43% (for strain 48, P < 0.001), 29% (for strain 75, P < 0.005), and 42% (for strain 111, P < 0.001) for the 9-day period compared to control mice given phosphate-buffered saline. Thus, PorA provided appreciable protection against colonization with heterologous serotypes.

scholarly journals The Rho-Independent Transcription Terminator for the porA Gene Enhances Expression of the Major Outer Membrane Protein and Campylobacter jejuni Virulence in Abortion Induction

2019 ◽  
Vol 87 (12) ◽  
Author(s):  
Lei Dai ◽  
Zuowei Wu ◽  
Changyun Xu ◽  
Orhan Sahin ◽  
Michael Yaeger ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Campylobacter Jejuni ◽  
Outer Membrane Protein ◽  
Fluorescent Protein ◽  
Transcript Level ◽  
Major Outer Membrane Protein ◽  
Pcr Analysis ◽  
Transcription Terminator ◽  
Content Type

ABSTRACT Campylobacter jejuni is a leading cause of foodborne illnesses worldwide. Its porA gene encodes the major outer membrane protein (MOMP) that is abundantly expressed and has important physiological functions, including a key role in systemic infection and abortion induction in pregnant animals. Despite the importance of porA in C. jejuni pathogenesis, mechanisms modulating its expression levels remain elusive. At the 3′ end of the porA transcript, there is a Rho-independent transcription terminator (named TporA in this study). Whether TporA affects the expression and function of MOMP remains unknown and is investigated in this study. Green fluorescent protein (GFP) fusion constructs with the porA promoter at the 5′ end and an intact TporA or no TporA at the 3′ end of the gfp coding sequence revealed that both the transcript level of gfp and its fluorescence signals were more than 2-fold higher in the construct with TporA than in the one without TporA. Real-time quantitative PCR (qRT-PCR) analysis of the porA mRNA and immunoblot detection of MOMP in C. jejuni showed that disruption of TporA significantly reduced the porA transcript level and the expression of MOMP. An mRNA decay assay demonstrated that disruption of TporA resulted in a shortened transcript half-life of the upstream gfp or porA gene, indicating that TporA enhances mRNA stability. In the guinea pig model, the C. jejuni construct with an interrupted TporA was significantly attenuated in abortion induction. Together, these results indicate that TporA enhances the expression level of MOMP by stabilizing its mRNA and influences the virulence of C. jejuni.

Sign in / Sign up

Export Citation Format

Share Document