Quantitative Real-time PCR using Lactobacilli as Livestock Probiotics

Real-time PCR을 이용한 가축생균제용 유산균 정량분석

This study was conducted using quantitative real-time PCR using Lactobacilli as probiotics. Quantitative real-time PCR (RT PCR) was conducted via a method involving SYBR Green 1 and a probe. Plasmid DNA was cloned using the 16S-23S rRNA intergenic species region. Gene clones were diluted from $10^2$ to $10^{10}$. Standard curves were constructed via Ct values obtained from the results of Real-time PCR via the aforementioned SYBR Green 1 and probe method. Plasmid DNA was also cloned using the 16S-23S rRNA intergenic species region and the gene clones were diluted from $10^2$ to $10^{10}$ copy numbers via the probe method. Using RT PCR, a standard curve of plasmid DNA copy numbers was also determined. The slope value for the Y-axis intercept and $R^2$ value were measured as -3.346, 33.18, and 0.993, respectively, via the first method. For the second method, the slope value for the Y-axis intercept and $R^2$ were -3.321, 31.10 and 0.995, respectively. The PCR inhibitor could not express the detection curve at a copy number over $10^{10}$ via either method, owing to high DNA density. The DNA extract from probiotics was diluted without pre-culturing, and 16 products were amplified via both methods. The Ct value was 11.06~18.12 in the first method and 16.74~22.11 in the second method. Measured probiotics and log copy values were largely similar among the methods used. It was concluded that both methods are effective for analysis, but further research will be required to verify the optimal method.

본 연구는 가축생균제용 유산균을 Real-time PCR정량분석법을 이용하여 분석하였다. SYBR Green1 방법과 Probe 방법을 이용하여 표준곡선을 제작한 결과, SYBR Green1 방법에서는 Slope 값이 -3.346이었고, Y절편은 33.18, $R^2$ 값은 0.993으로 나타났으며, Probe 방법에서는 Slope값이 -3.321이었고, Y절편은 39.10, $R^2$ 값은 0.995로 나타나, 이를 이용한 표준곡선 제작이 가능함을 알 수 있었다. SYBR Green1 방법을 이용한 생균제의 Lactobacilli 정성 정량 분석결과 Real-time PCR값은 4.46~6.56 log copies로 나타났고, 생균수 측정 결과 값은 5.63~7.59 log CFU/g로 나타났으며, Probe 방법을 이용한 생균제의 Lactobacilli 정성 정량 분석결과에서는 Real-time PCR 값은 5.51~7.00 log copies로 나타났으며, 생균수 측정 결과 값은 5.63~7.59 log CFU/g로 나타났다. 본 연구에서 실시한 RT PCR법은 3~4일이 소요되는 기존의 배지법과 비교하여 24시간 이내에 신속하게 검출이 가능하다고 여겨지며, 또한 RT PCR을 이용한 분석방법에서도 dye 사용과 primer 사용에 따라 결과값이 차이가 나타났음을 확인할 수 있었으며, Probe 방법을 이용하여 실험 한 결과가 민감한 결과를 나타내었음을 확인 할 수 있었다.