title: Variation of chemosensory receptor content of Campylobacter jejuni strains and modulation of receptor gene expression under different in vivo and in vitro growth conditions.
abstract: BACKGROUND
  Chemotaxis is crucial for the colonisation/infection of hosts with Campylobacter jejuni. Central to chemotaxis are the group A chemotaxis genes that are responsible for sensing the external environment. The distribution of group A chemoreceptor genes, as found in the C. jejuni sequenced strains, tlp1-4, 7, 10 and 11 were determined in 33 clinical human and avian isolates.
  
  
  RESULTS
  Group A tlp gene content varied among the strains with genes encoding tlp1 (aspartate receptor, ccaA) and tlp7 present in all strains tested, where as tlp11 was present in only one of our international collection clinical isolates, C. jejuni 520, but was more prevalent (9/13) in the freshly isolated clinical stains from patients who required hospitalisation due to C. jejuni infection (GCH1-17). Relative expression levels of the group A tlp genes were also determined in C. jejuni reference strains NCTC 11168-GS, 11168-O and 81116 using cells grown in vitro at 37°C, 42°C and maintained at room temperature and with cells isolated directly from murine and avian hosts by immune magnetic separation without subsequent culture. Gene expression of tlp genes was varied based on strain, growth conditions and in vivo isolation source. Tlp1, although the most conserved, showed the lowest and most varied mRNA expression and protein production under laboratory conditions. Tlp7 was highly expressed at most conditions tested, and gene expression was not influenced by the tlp7 gene encoding a full length protein or one expressed as separate periplasmic and cytoplasmic domains.
  
  
  CONCLUSIONS
  We have shown that chemosensory receptor set variation exists among C. jejuni strains, but is not dependent on the isolation source.
authors: Institute for Glycomics, Griffith University Gold Coast Campus, Griffith University, Griffith, Australia.
authors: Christopher J
authors: CJ
authors: Day
authors: Lauren E
authors: LE
authors: Hartley-Tassell
authors: Lucy K
authors: LK
authors: Shewell
authors: Rebecca M
authors: RM
authors: King
authors: Greg
authors: G
authors: Tram
authors: Serena K
authors: SK
authors: Day
authors: Evgeny A
authors: EA
authors: Semchenko
authors: Victoria
authors: V
authors: Korolik
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D002169:Campylobacter Infections / Q000382:microbiology / Q000662:veterinary; D016123:Campylobacter jejuni / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology; D002633:Chemotaxis; D002645:Chickens; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins