Bickley J, Short J K, McDowell D G, Parkes H C
Laboratory of the Government Chemist, Analytical Molecular Biology Group, Teddington, Middlesex, UK.
Lett Appl Microbiol. 1996 Feb;22(2):153-8. doi: 10.1111/j.1472-765x.1996.tb01131.x.
DNA from Listeria monocytogenes was used as the model system from this investigation, with PCR primers based on the listeriolysin O gene. Under standard polymerase chain reaction (PCR) conditions and with no prior treatment, amplification failed in the presence of more than 5% milk. Since inhibition of the PCR occurred at the same milk concentrations with full fat, half fat and fat-free milk, inhibition was not attributed to the fat content of the milk. Calcium ions were, however, identified as a major source of PCR inhibition. The results demonstrated that the inhibitory effects of calcium ions and milk could be partially reversed by increasing the magnesium concentration in the reaction to well above the standard levels normally required for PCR. This work has important implications for the use of the PCR in the direct detection of food pathogens.
来自单核细胞增生李斯特菌的DNA被用作本次研究的模型系统，使用基于李斯特菌溶血素O基因的PCR引物。在标准聚合酶链式反应（PCR）条件下且未经事先处理时，在存在超过5%牛奶的情况下扩增失败。由于在全脂、半脂和脱脂牛奶的相同牛奶浓度下均发生PCR抑制，因此抑制作用并非归因于牛奶的脂肪含量。然而，钙离子被确定为PCR抑制的主要来源。结果表明，通过将反应中的镁浓度提高到远高于PCR通常所需的标准水平，可以部分逆转钙离子和牛奶的抑制作用。这项工作对于PCR在直接检测食品病原体中的应用具有重要意义。
