srtA基因缺失对LM环境应激及生物膜生成能力的影响

The effects of srtA gene deletion on environmental stress adaptability and biofilm formation of Listeria monocytogenes

为了解srtA对单增李斯特菌(LM)环境应激及生物膜生成的影响,本实验比较了缺失株LM90SB2-△srtA与野生株LM90SB2在不同温度、pH、渗透压、H_2O_2条件下的生长情况、药物敏感性及生物膜生成能力的差异。结果表明:缺失株在致死酸(pH 3.5的盐酸和乳酸)条件下的存活率(55%和54%)低于野生株在致死酸(pH 3.5的盐酸和乳酸)条件下的存活率(71%和75%),统计学处理结果显示其差异显著;缺失株在培养12、24 h后生物膜交联程度和着色区域厚度低于野生株。但在不同温度、pH、渗透压、H_2O_2条件下的生长以及药物敏感性上均无明显差异。提示srtA分选的表面蛋白可能参与致死酸度条件下的存活和生物膜的密集度。

To understand the role of surface proteins anchored to cell wall by srtA in environmental stress adaptability and biofilm formation ability of Listeria monocytogenes,the growth curve of wild-type strain(LM90SB2) and srtA deletion strain(LM90SB2-△srtA) cultured in different temperatures,pH,osmolality,H_2O_2 conditions were measured,and drug sensitivity and biofilm formation ability of two strains were also detected.The results showed that the survival rate of LM90SB2- A srtA in pH3.5 medium adjusted by hydrochloric acid and lactic acid was 55% and 54% respectively,lower than 71% and 75% of LM90SB2(P<0.05).The biofilm thickness and crosslink degree of LM90SB2-△srtA were less than LM90SB2 after 12 h and24 h.But there were no differences cultured in different temperatures,pH,osmolality,H_2O_2 and drug sensitivity.Over all,the results confirmed that the surface proteins anchored by srtA may play a role in survival rate under the lethal acid conditions and biofilm formation ability.