Structural analysis of the full-length gene encoding a fibronectin-binding-like protein (CadF) and its adjacent genetic loci within Campylobacter lari

Thus, cadF (-like) gene is highly conserved among C. lari organisms. Transcription of the cadF (-like) gene in C. lari cells in vivo was also confirmed and the transcription initiation site was determined. A peptidoglycan-associating alpha-helical motif in the C-terminal regions of some bacterial cell-surface proteins was completely conserved amongst the putative cadF (-like) ORFs from the C. lari isolates.The putative cadF (-like) ORFs from all C. lari isolates were nine amino acid larger than those from C. jejuni, and showed amino acid residues 137 -140 of FALG (50% identity), instead of the FRLS residues of the maximal fibronectin-binding activity site demonstrated within C. jejuni CadF. A neighbor joining tree constructed based on cadF (-like) gene sequence information formed a major cluster consisting of C. lari isolates, separating from the other three thermophilic campylobacters.Thermophilic Campylobacter species, primarily Campylobacter jejuni and C. coli, are curved, Gram-negative organisms, belonging to the ε-Proteobacteria, and are the most commonly recognized cause of acute bacterial diarrhea in the Western world [1-3].Campylobacter lari is a relatively recently discovered thermophilic Campylobacter species that was first isolated from mammalian and avian species, particularly seagulls of the genus Larus [1,4]. C. lari has also been shown to be a cause of clinical infection [5-9].In addition, an atypical group of isolates of urease-positive thermophilic Campylobacter (UPTC) have been isolated from the natural environment in England in 1985 [10]. Thereafter, these organisms were described as a biovar or variant of C. lari [11,12]. Subsequent reports described four human isolates in France [11,13]. Some additional isolates of UPTC have also been reported in Northern Ireland [14-16] in The Netherlands [17] and in Japan [18,19]. Thus, these two representative taxa, namely urease-negative (UN) C. lari and UPTC occur within the species of C. lari [20].Bacteria