TABLE 1.

Summary of primer characteristics and PCR conditions

Primers	Target (specificity)	PCR conditions	Reference
amoA-1F-amoA-2R	amoA gene (AOB β-Proteobacteria)	5 min at 94°C, followed by 42 cycles of 1 min at 94°C, 1 min 30 s at 60°C, and 1 min 30 s at 72°C, followed by a 10-min final extension at 72°C	46
CTO189F-GC or CTO189F-CTO654r	16S rRNA gene (AOB β-Proteobacteria)	3 min at 94°C, followed by 38 cycles of 30 s at 92°C, 30 s at 57°C, and 45 s at 72°C, followed by a 5-min final extension at 72°C	35
357F-GC or 357F-518R	16S rRNA gene (universal)	5 min at 94°C, followed by 25 cycles of 1 min at 94°C, 1 min at 65°C (−1°C each 2 cycles and 5 cycles at 55°C), and 1 min at 72°C, followed by a 5-min final extension at 72°C	38