FIG. 5.

Comparison of structural (16S rRNA) and functional (amoA and nirK) gene phylogenies by distance analysis. (A) Deduced amino acid sequences (179 amino acids) from nitrifier nirK genes; (B) amoA gene (525 bp) for ammonia monooxygenase; (C) 16S rRNA gene (∼1,100 bp) from nitrifying bacteria. Distances were calculated from amino acid sequences using Dayhoff PAM 100 matrix (12) and for nucleic acid sequences using the Kimura two-parameter model (22). The 16S rRNA sequences for URW, NO3W, C-45, C-113a, and TA-921i-NH4 are from Voytek (42). Sequences from this study are in bold type. Bootstrap values over 50% are shown. The scale bars indicate substitutions per site.