RT1
The V3-V4 regions of 16S rRNA were amplified by PCR with primers of     the forward primer 338F (5'-ACTCCTACGGGAGGCAGCAG-3') and the reverse primer 806R     (5'-GGACTACHVGGGTWTCTAAT-3'). Reaction conditions were as follows: 95     pre-denaturation for 3min; 95denaturation 30s, 55 annealing 30s, 72 extension 30s,     25 cycles. Lastly, each sample was extended for 5min with 3 PCR replicates, and the     PCR products with 3 replicates were mixed. The PCR products were purified using the     AxyPrep DNA Gel ExtractionKit and quantified by the Quantus     Fluorometer.