单增李斯特菌WaX12及其sigB缺失突变株在不同pH下生长动力学的比较

为了探究σB因子对单增李斯特菌（LM）的生长影响，比较了LM-WaX12及其sigma B缺失突变株在不同pH值下生长动力学的差异。作者运用重叠延伸PCR（SOE-PCR）和同源重组的方法构建缺失SigB基因的LM突变株WaX12-?驻sigB；利用sigB外围引物扩增其两侧片段鉴定突变株，并且通过修正的Logistic模型拟合两个菌株在不同酸碱度下（pH 5~9）的生长曲线，分析各生长参数之间的差异性。结果表明，单增李斯特菌sigB缺失突变株构建成功；WaX12-?驻sigB和WaX12在pH 5的环境下最大比生长速率μmax、延滞期λ与最大菌浓MPD-OD均存在显著性差异（P<0.05），而在中性和碱性环境下二者明显差异。
To explore the effect of σB in the growth of Listeria monocytogenes（LM），we compared the growth kinetics of LM-WaX12 and its dull sigB mutant at different pH values. We used splicing by overlap extension PCR（SOE-PCR） and homologous recombination to construct the sigmaB gene deleted mutant；The mutant was identified by the fragments that amplified by two sides primer of sigB. The growth curve of WaX12 and WaX12-sigB were fitted by modified Logistic model from pH 5 to pH 9，as well as both growth kinetic parameters were analyzed. The results showed the ?驻sigB mutant was constructed correctly. The maximum exponential growth rate（μmax），lag phase duration（λ） and maximum population density（MPD-OD） of WaX12-?驻sigB and WaX12 had all significant difference（p＜0.05） at pH 5，but had no different significant at neutral and alkali