Comparison of Growth Kinetics of Listeria monocytogenes WaX12 and Dull sigB Mutant at Different pH Values

Abstract:

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.