FIG. 4.

(A) Phylogenetic positions of Mineral Park mesophilic heterotrophic acidophiles, MPH2 and MPH3, relative to Acidiphilium and Acidocella species of the alpha subclass of Proteobacteria (unrooted). Scale bar, 1% sequence divergence. (B) Phylogenetic position of Mineral Park moderately thermophilic acidophiles, MPH5 and MPH6, relative to other sulfobacilli of the high-G+C DNA content gram-positive bacteria (unrooted). From the positions of MPH5 and MPH6, they would be predicted to be non-iron-oxidizing sulfobacilli. Quotation marks indicate nonauthoritative nomenclature.