实时荧光定量PCR技术监测腌制麻竹笋中乳酸乳球菌动态变化

采用实时荧光定量聚合酶链式反应（quantitative real-time polymerase chain reaction，qRT-PCR）技术定量监测6 g/100 mL盐质量浓度腌制麻竹笋中乳酸乳球菌（Lactococcus lactis）的动态变化。经乳酸乳球菌标准菌株基因组DNA提取、标准阳性质粒制备、标准曲线绘制、各时期竹笋腌制发酵液中细菌基因组DNA提取和乳酸乳球菌qRTPCR特异性扩增，对腌制液中乳酸乳球菌进行定量检测。结果表明，在腌制过程中（0～63 d），随着腌制时间的延长，乳酸乳球菌含量逐渐升高，在腌制14 d时达到最大值（4.63×108 copies/μL），与0 d（2.41×102 copies/μL）相比增加了6 个数量级，而后浓度缓慢降低，在腌制63 d时浓度为5.02×106 copies/μL。qRT-PCR技术为定量监测腌制麻竹笋中微生物的动态变化提供了一条可靠、快速的有效途径。

Detection of Lactococcus lactis in Pickled Ma Bamboo Shoots by Quantitative Real-time PCR

The dynamic changes of Lactococcus lactis in pickled Ma bamboo shoots with 6 g/100 mL salt concentration were
studied by quantitative real-time polymerase chain reaction (qRT-PCR). After the DNA extraction from standard Lactococcus
lactis, preparation of positive plasmids, protraction of standard curve, DNA extraction from samples at different fermentation
stages and qRT-PCR, and quantitative detection were performed. The results showed that during fermentation (0–63 days),
the concentration of Lactococcus lactis increased gradually from 2.41 × 102 copies/μL (day 0) to the maximum value of
4.63 × 108 copies/μL (day 14), an increase by six orders of magnitude, followed by a slow decrease to 5.02 × 106 copies/μL
at day 63. In conclusion, qRT-PCR technology provides a reliable, fast and effective way for the quantitative analysis of
bacteria in pickled Ma bamboo shoots.