FIG. 2.

Neighbor-joining trees showing phylogenetic relationships among phylotypes obtained in this study and reference 16S rRNA gene sequences retrieved from the nucleotide sequence databases for γ-Proteobacteria (A) and δ-Proteobacteria (B). The bold vertical bar to the right of the tree in panel A represents the range of Thiotrichales, while the one to the right of the tree in panel B represents Desulfobulbaceae. The numbers at the branch nodes are bootstrap values per 100 trials; only values of >50 are shown. Accession numbers for the reference sequences are shown in parentheses.