All PCR reactions were carried out using PuReTaq
Ready-to-go beads (Amersham Biosciences); 0.5 l DNA sample
was added to 23 l dH2O and 0.5 l each 10 mM primer. PCRs were
carried out in triplicate and were pooled to reduce PCR bias. For the
restriction enzyme digests, 12.5 l 16 s rDNA PCR product was incubated
with 1 l AluI and 7.5 l amoA PCR product was incubatedwith 1 l HphI for 5 h at 37 ◦C.