Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017160 (gastroenteritis)
 11,398 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Campylobacter jejuni is the leading cause of bacterial gastroenteritis in humans in developed countries throughout the world. This bacterium frequently promotes a commensal lifestyle in the gastrointestinal tracts of many animals including birds and consumption or handling of poultry meats is a prevalent source of C. jejuni for infection in humans. To understand how the bacterium promotes commensalism, we used signature-tagged transposon mutagenesis and identified 29 mutants representing 22 different genes of C. jejuni strain 81-176 involved in colonization of the chick gastrointestinal tract. Among the determinants identified were two adjacent genes, one encoding a methyl-accepting chemotaxis protein (MCP), presumably required for proper chemotaxis to a specific environmental component, and another gene encoding a putative cytochrome c peroxidase that may function to reduce periplasmic hydrogen peroxide stress during in vivo growth. Deletion of either gene resulted in attenuation for growth throughout the gastrointestinal tract. Further examination of 10 other putative MCPs or MCP-domain containing proteins of C. jejuni revealed one other required for wild-type levels of caecal colonization. This study represents one of the first genetic screens focusing on the bacterial requirements necessary for promoting commensalism in a vertebrate host.
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PMID:Identification of Campylobacter jejuni genes involved in commensal colonization of the chick gastrointestinal tract. 1506 34

Campylobacter jejuni is a leading cause of bacterial gastroenteritis in humans throughout the world, but infection of animals, especially poultry, results in a commensal colonization of the intestines. We previously found that a mutant lacking docA, which encodes a putative cytochrome c peroxidase (CCP), demonstrates up to a 10(5)-fold reduction in colonization of the chick cecum compared to wild-type C. jejuni strain 81-176. Predictions from genomic sequences identified CJJ0382 as a second locus in C. jejuni encoding a CCP, making the bacterium unusual in having two putative CCPs. To understand what advantages are imparted by having two putative CCPs, we compared the colonization requirements of C. jejuni mutants lacking DocA or Cjj0382. Unlike the DeltadocA mutant, a DeltaCJJ0382 mutant demonstrates a maximal 50-fold colonization defect that is dependent on the inoculum dose. The colonization differences of mutants lacking DocA or Cjj0382 suggest that the two predicted CCPs are unlikely to perform redundant functions during in vivo growth. In the characterizations of DocA and Cjj0382, we found that they are stable periplasmic proteins with an apparent heme-dependent peroxidase activity, which are characteristics of bacterial CCPs. However, the peroxidase activities of the proteins do not appear to contribute to resistance to hydrogen peroxide. Instead, we found that resistance to hydrogen peroxide in C. jejuni is mostly attributed to the cytoplasmic catalase KatA. Our data suggest that DocA and Cjj0382 have characteristics of CCPs but likely perform different physiological functions for the bacterium in colonization that are not related to resisting oxidative stress.
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PMID:Characterization of two putative cytochrome c peroxidases of Campylobacter jejuni involved in promoting commensal colonization of poultry. 1808 14