Affiliation:
1. Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, Sir Graeme Davies Building, 120 University Place, University of Glasgow, Glasgow G12 8TA, UK
Abstract
The tbpBA operon was sequenced in 42 representative isolates of Mannheimia haemolytica (32), Mannheimia glucosida (6) and Bibersteinia trehalosi (4). A total of 27 tbpB and 20 tbpA alleles were identified whilst the tbpBA operon was represented by 28 unique alleles that could be assigned to seven classes. There were 1566 (34.8 % variation) polymorphic nucleotide sites and 482 (32.1 % variation) variable inferred amino acid positions among the 42 tbpBA sequences. The tbpBA operons of serotype A2 M. haemolytica isolates are, with one exception, substantially more diverse than those of the other M. haemolytica serotypes and most likely have a different ancestral origin. The tbpBA phylogeny has been severely disrupted by numerous small- and large-scale intragenic recombination events. In addition, assortative (entire gene) recombination events, involving either the entire tbpBA operon or the individual tbpB and tbpA genes, have played a major role in shaping tbpBA structure and it's distribution in the three species. Our findings indicate that a common gene pool exists for tbpBA in M. haemolytica, M. glucosida and B. trehalosi. In particular, B. trehalosi, M. glucosida and ovine M. haemolytica isolates share a large portion of the tbpA gene, and this probably reflects selection for a conserved TbpA protein that provides effective iron uptake in sheep. Bovine and ovine serotype A2 lineages have very different tbpBA alleles. Bovine-like tbpBA alleles have been partially, or completely, replaced by ovine-like tbpBA alleles in ovine serotype A2 isolates, suggesting that different transferrin receptors are required by serotype A2 isolates for optimum iron uptake in cattle and sheep. Conversely, the tbpBA alleles of bovine-pathogenic serotype A1 and A6 isolates are very similar to those of closely related ovine isolates, suggesting a recent and common evolutionary origin.
Reference41 articles.
1. Taxonomic relationships of the [ Pasteurella ] haemolytica complex as evaluated by DNA–DNA hybridizations and 16s rRNA sequencing with proposal of Mannheimia haemolytica gen. nov., comb. nov., Mannheimia granulomatis comb. nov., Mannheimia glucosida sp. nov., Mannheimia ruminalis sp. nov. and Mannheimia varigena sp. nov;Angen;Int J Syst Bacteriol,1999
2. A common gene pool for the Neisseria FetA antigen;Bennett;Int J Med Microbiol,2009
3. Meningococcal genetic variation mechanisms viewed through comparative analysis of serogroup C strain FAM18;Bentley;PLoS Genet,2007
4. Reclassification of [ Pasteurella ] trehalosi as Bibersteinia trehalosi gen. nov., comb. nov;Blackall;Int J Syst Evol Microbiol,2007
5. Variation of the factor H-binding protein of Neisseria meningitidis;Brehony;Microbiology,2009
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