The analysis of oral microbial communities of wild-type and toll-like receptor 2-deficient mice using a 454 GS FLX Titanium pyrosequencer

Abstract

Background: Although mice have long served as an animal model for periodontitis, information on the composition of their indigenous oral microbiota is limited. The aim of the current study was to characterize mouse oral bacterial flora by applying extensive parallel pyrosequencing using the latest model pyrosequencer, a Roche/454 Genome Sequencer FLX Titanium. In addition, the effect of Toll-like receptor (TLR) 2 deficiency on oral microbiota was evaluated.

Results: Eight oral bacterial communities of wild-type (n = 4) and TLR2 knock-out (n = 4) C57BL/6 mice were characterized by analyzing 80,046 reads of 16S rRNA genes obtained by pyrosequencing. Excluding the PCR primers, the average length of each sequencing product was 443 bp. The average species richness of the murine oral bacterial communities was estimated to be about 200, but the communities were dominated by only two main phyla and several species. Therefore, the bacterial communities were relatively simple. The bacterial composition of the murine oral microbiota was significantly different from that of humans, and the lack of TLR2 had a negligible effect on the murine oral microbiota.

Conclusion: Pyrosequencing using the Roche/454 FLX Titanium successfully characterized mouse oral bacterial communities. The relatively simple oral bacterial communities of mice were not affected by TLR2 deficiency. These findings will provide a basis for future studies on the role of periodontal pathogens in the murine model of periodontitis.

Figure 1

The major phyla and species/phylotypes identified in murine oral bacterial communities. (A) Only phyla with a mean relative abundance greater than 0.01% are shown. (B) The top ten dominant species/phylotypes are shown. The right panel presents the mean values of the WT and KO groups. *, p < 0.05.

Figure 2

Rarefaction analysis performed by the RDP pipeline. Repeated samples of phylotype subsets were used to evaluate whether further sampling would likely identify additional taxa.