IADR Abstract Archives
Comparative genomics of monkey and human strains of Aggregatibacter actinomycetemcomitans
Objectives: The objective of this study was to perform comparative phylogenetic and functional analysis of Aggregatibacter actinomycetemcomitans strains isolated from the oral cavity of humans and primates.
Methods: Aa was obtained from primates from three primate centers . 120 primates were surveyed for Aa. Eight Aa strains were selected for DNA sequencing. Phylogenetic analysis was performed on the whole Aa genome as well as on Aa adhesins, Aae and ApiA. In addition, buccal epithelial cell (BEC) binding and mRNA expression was assessed for selected human and monkey Aa strains.
Results: In all phylogenetic analyses of the 8 primate strains evaluated, 2 primate strains aligned with the human strains. When Aae sequences were compared, analysis showed minor differences in DNA which were nullified when DNA was translated into protein. Further Aa binding to BECs and mRNA expression showed similarity when human and monkey strains of Aa were compared for Aae binding to BECs. In contrast, when ApiA sequences were compared complete sequence identity was found in the C-terminus but two of the monkey strains showed an insertion in the N-terminal binding region and thus were not well aligned with the human strains assessed. mRNA expression of ApiA was more than 100 fold lower in the monkey strains as compared to human strains tested. Moreover attachment to BECs via ApiA adhesins was 3x’s lower in the monkey strains as compared to human strains (p<0.05).
Conclusions: These studies will assist us in our effort to identify the critical BEC binding domain of the Aa ApiA adhesin.
Methods: Aa was obtained from primates from three primate centers . 120 primates were surveyed for Aa. Eight Aa strains were selected for DNA sequencing. Phylogenetic analysis was performed on the whole Aa genome as well as on Aa adhesins, Aae and ApiA. In addition, buccal epithelial cell (BEC) binding and mRNA expression was assessed for selected human and monkey Aa strains.
Results: In all phylogenetic analyses of the 8 primate strains evaluated, 2 primate strains aligned with the human strains. When Aae sequences were compared, analysis showed minor differences in DNA which were nullified when DNA was translated into protein. Further Aa binding to BECs and mRNA expression showed similarity when human and monkey strains of Aa were compared for Aae binding to BECs. In contrast, when ApiA sequences were compared complete sequence identity was found in the C-terminus but two of the monkey strains showed an insertion in the N-terminal binding region and thus were not well aligned with the human strains assessed. mRNA expression of ApiA was more than 100 fold lower in the monkey strains as compared to human strains tested. Moreover attachment to BECs via ApiA adhesins was 3x’s lower in the monkey strains as compared to human strains (p<0.05).
Conclusions: These studies will assist us in our effort to identify the critical BEC binding domain of the Aa ApiA adhesin.