FIG. 2.

Quantification of copies of the amoA gene (A) and the Nitrospira 16S rDNA gene (B). Numbers of determined copies were calculated by using cPCR as described in Materials and Methods with a PCR product of clone M-20 (A) or a plasmid containing the 16S rDNA gene of Nitrospira (B). Error bars indicate the standard deviations of the means (n = 3 or 4). The dashed lines indicate a ratio of actual number of copies to determined number of copies of 1:1.