FIG. 1.

Phylogenetic tree of Lactobacillus EF-Tu and Bifidobacterium EF-Tu based on nucleotide sequence homology. The phylogenetic tree was constructed by the neighbor-joining method. The scale bar represents sequence divergence. In this tree topology, the phylogenetic distance between organisms is the sum of the horizontal segments. L. acidophilus group A includes the species L. acidophilus, L. amylovorus, L. gallinarum, and L. crispatus; L. acidophilus group B includes only L. gasseri and L. johnsonii. Bootstrap values are reported for a total of 1,000 replicates. tufA and tufB indicate the tufA and tufB genes, respectively.