Branch lengths are drawn to scale. Phylogenetic analyses of recA partial gene sequences Our phylogenetic inferences based on recA partial gene sequences yielded CH5424802 supplier clearer insights into the branching order of the members of the salivarius group (Figure 3), which were clustered together in all the ML and MP bootstrap replicates, while the two S. vestibularis strains formed a united clade in all the replicates, and the three S. thermophilus strains branched together in the vast majority of the bootstrap replicates. The monophyly of the S. salivarius species was

recovered in 98% of the MP bootstrap replicates, although ML-based phylogenetic inferences could not discriminate between paraphyletic and monophyletic S. salivarius clades (52% buy KU55933 vs. 48% of the bootstrap replicates, respectively). Like the secA-based phylogenetic inferences, the analyses derived from the recA gene sequences strongly supported a sister-relationship between the S. vestibularis and S. thermophilus species. The node comprising these two species was robust and was recovered in all the ML and MP bootstrap replicates. Figure 3 Branching order of members of the salivarius group as inferred from ML and MP analyses of recA partial gene sequences (798 positions; Ilomastat in vitro 309 variable,

289 phylogenetically informative). The best ML tree computed with PHYML 3.0 under the GTR+Γ4+I model of nucleotide substitution is shown here. Bootstrap support for the major nodes is indicated over the corresponding nodes: ML values left, MP values right. Asterisks denote nodes that were retrieved in all the bootstrap replicates. Dashes indicate nodes that were retrieved in fewer than 50% of the bootstrap replicates. Streptococcal species belonging to the salivarius group are shown in orange (S. salivarius), blue (S. vestibularis) or green (S. thermophilus). Other streptococcal species shown in black were outgroups. Branch lengths are drawn to scale. Phylogenetic analyses of 16S rRNA-encoding gene sequences Building on the phylogeny published by Kawamura et al. [2], we reinvestigated the branching order among the salivarius streptococci using

16S rRNA-encoding gene sequences and expanded taxon sampling within the salivarius group. As can be seen in Figure 4, even though the salivarius group Calpain was recovered in all the bootstrap replicates, the branching order within this taxonomic entity was not well defined. Of the three species, only S. thermophilus composed a monophyletic assemblage. The other two, S. vestibularis and S. salivarius, were not resolved. This contrasted with the results obtained by Kawamura et al. [2], who reported that the S. vestibularis and S. thermophilus species branched together with strong bootstrap support. It should be noted, however, that the 16S rRNA-encoding gene sequences exhibited almost no variability among salivarius streptococci.