FIG. 5.

Phylogenetic tree showing the relationships of 16S rRNA phylotypes affiliated with the Deltaproteobacteria. The basic tree of reference sequences was reconstructed using the maximum-parsimony method based on a comparison of more than 1,400 nucleotides. Bootstrap values were obtained from 1,000 replications, and >90%, 70 to 89%, and <69% are shown with black, gray, and open circles, respectively. Clones were designated LH (heavy fraction of the labeled ¹³C treatment; in boldface) and UH (heavy fraction of the unlabeled treatment). Numbers in parentheses represent the expected T-RF lengths of the clones. The scale bar represents 10% sequence divergence. GenBank accession numbers of reference sequences are given.