Campylobacter jejuni Glycosylation Island Important in Cell Charge, Legionaminic Acid Biosynthesis, and Colonization of Chickens

Abstract

Previously, we identified five genes (Cj1321 to Cj1326, of which Cj1325 and Cj1326 are a single gene) in the O-linked flagellin glycosylation island that are highly prevalent in Campylobacter jejuni isolates from chickens. We report mutagenesis, functional, and structural data to confirm that this locus, and Cj1324 in particular, has a significant contributory role in the colonization of chickens by C. jejuni. A motile ⌬Cj1324 mutant with intact flagella was considerably less hydrophobic and less able to autoagglutinate and form biofilms than the parent strain, 11168H, suggesting that the surface charge of flagella of Cj1324-deficient strains was altered. The physical and functional attributes of the parent were restored upon complementation. Structural analysis of flagellin protein purified from the ⌬Cj1324 mutant revealed the absence of two legionaminic acid glycan modifications that were present in the parent strain, 11168H. These glycoform modifications were shown to be prevalent in chicken isolates and confirm that differences in the highly variable flagellin glycosylation locus can relate to the strain source. The discovery of molecular mechanisms influencing the persistence of C. jejuni in poultry aids the rational design of approaches to control this problematic pathogen in the food chain.

Campylobacter jejuni 81-176 forms distinct microcolonies on in vitro-infected human small intestinal tissue prior to biofilm formation

“…Published work relates to the formation of biofilms in the environment as a mechanism of persistence and possible transmission and survival within the poultry house (Howard et al, 2009;Svensson et al, 2009). Water in poultry houses has been shown to be a possible source of infection for birds and it has also been shown that C. jejuni is present in biofilms in drinking apparatus (Hanning et al, 2008).…”

Sulphite : cytochrome c oxidoreductase deficiency in Campylobacter jejuni reduces motility, host cell adherence and invasion

“…These so-called post-translational modification (ptm) genes are cj1324 (ptmG), cj1325/6 (ptmH), cj1327-cj1330 (ptmC, ptmD, ptmE, ptmF), cj1331 (ptmB) and cj1332 (ptmA) (McNally et al, 2007). Although knowledge of the importance of Oglycosylation by LegAm is limited, recent investigations by Howard et al (2009) gave a first insight into its biological relevance. A C. jejuni cj1324 mutant showed full motility, but less hydrophobicity and impaired autoagglutination and biofilm formation due to the absence of two LegAm glycan modifications.…”

“…However, we also could clearly show reduced autoagglutination but no alterations in biofilm formation (data not shown). In contrast to Howard et al (2009), we did not investigate the genes cj1321-cj1323, but we examined all genes required for LegAm synthesis with regard to altered transcription. This revealed transcription of ptmB (cj1331), ptmC (cj1327) and ptmE (cj1329) to be strongly downregulated in the cj0005c mutant, whereas the transcription of genes ptmA (cj1332), ptmF (cj1330) and ptmG (cj1324) was significantly downregulated but to a lesser extent.…”

“…The parental strain B2, its knockout mutant and the complemented mutant were tested five times each. The data obtained were normalized according to Howard et al (2009): the OD 600 measured after 24 h was subtracted from the OD 600 from the start of the experiment; the values obtained were divided by the initial OD 600 and were finally multiplied by 100 in order to give the percentage autoagglutination.…”

Integrated Genomic Approaches to Enhance Genetic Resistance in Chickens

“…Bacterial pathogens associated with enteric fever use such strategies (124), and it is noteworthy that C. jejuni can sometimes be found in deep muscle and visceral organs. C. jejuni may evade detection by avian TLR5, because mutant strains lacking genes responsible for glycosylation of the flagella elicit stronger proinflammatory cytokine responses in chick ceca and exhibit defects in intestinal persistence relative to the parent strain (125). Salmonella Typhimurium strains expressing the C. jejuni proteins CjaA or Peb1A elicit protection against intestinal colonization of chickens by C. jejuni (126), which suggests that immune control of C. jejuni in the avian intestines may be feasible.…”