该研究以食源性致病菌单增李斯特菌为研究对象，考察了培养时间、培养温度、pH值及NaCl浓度等不同环境因素对单增李斯特菌产群体感应信号分子Autoinducer-2（AI-2）活性与生物被膜形成的影响。结果表明：在对数生长期，单增李斯特菌AI-2活性随着菌密度增加而增加，到达稳定期后AI-2活性呈下降的趋势；在聚苯乙烯培养板中于37 ℃培养24 h，单增李斯特菌的生长量、生物被膜产生量及AI-2活性最高，分别是4 ℃下的7.65倍、11.14倍和4.40倍；在质量分数为0.5%~9.0%的NaCl添加量下，单增李斯特菌的生长量相近，NaCl质量分数为3.0%时，AI-2活性最高，相对荧光强度为6.159，而NaCl质量分数为9.0%时，生物被膜形成量与AI-2活性最低；pH值为5和9时的AI-2活性分别为对照组（pH值7.4）的0.11倍和0.13倍，均受到显著的抑制。以上结果说明单增李斯特菌的AI-2活性与生物被膜形成受环境因素的影响，为进一步研究LuxS/AI-2群体感应系统调控生物被膜形成及其淬灭提供参考。

We investigated the effects of different environmental factors, namely, culture time and temperature, pH, and NaCl concentration, on autoinducer (AI-2) activity and biofilm formation of the foodborne pathogen Listeria monocytogenes. The results revealed that during the logarithmic growth period, the AI-2 activity of L. monocytogenes was initially enhanced with an increase in cell density, although on reaching the stable growth period, the activity showed a subsequent declining trend. The highest values for growth, biofilm biomass, and AI-2 activity were recorded when L. monocytogenes was cultured in polystyrene culture plates at 37 ℃ for 24 h, which were 7.65-, 11.14-, and 4.40-fold higher than the values obtained at 4 ℃, respectively. Listeria monocytogenes showed similar growth performance in response to the addition of 0.5-9.0 wt.% NaCl, with AI-2 activity peaking at a NaCl mass fraction of 3.0% and a relative fluorescence intensity of 6.159. The lowest values of biofilm biomass and AI-2 activity were recorded at an NaCl mass fraction of 9.0%. Moreover, at pH value 5 and pH value 9, AI-2 activities were 0.11- and 0.13-fold compared to the control group (pH value 7.4), respectively, indicating a significant inhibition of activity at both low and high pH values. Collectively, these findings indicate that AI-2 activity and biofilm formation of L. monocytogenes are influenced by environmental factors. These findings will provide a reference for further research on the regulation of biofilm formation by the LuxS/AI-2 quorum sensing system and its quenching.

广东省基础与应用基础研究基金项目（2024A1515012695；2021A1515011083）；国家自然科学基金面上项目（31972046）；广东省科技计划项目（2020B1212060059）