Establishment of the real time-PCR(RT-PCR) standard curve. A. The standard curve for gI gene obtained by SYBR Green RT-PCR using recombinant plasmid pMD18-T-gI as template. B. The standard curve for β-actin gene obtained by SYBR Green RT-PCR using recombinant plasmid pMD18-T-β-actin. Ten-fold dilutions of standard DNA were used, as indicated in the x-axis, whereas the corresponding cycle threshold (CT) values are presented on the y-axis. Each dot represents the result of amplification of each dilution. The correlation coefficient and the slope value of the regression curve were calculated and are indicated.