茶多酚诱导铜绿假单胞菌交叉耐受性研究

Cross-resistance Induced by Tea Polyphenols in Pseudomonas aeruginosa

检测了亚致死浓度的茶多酚(Tea Polyphenols,TP)处理对铜绿假单胞菌交叉耐受性的诱导作用。铜绿假单胞菌暴露于1 mg·m L^(-1)茶多酚1 h后能够显著增强细菌对多种环境条件的耐受性,包括氧化剂(1 mmol·L^(-1)H_2O_2)、高温(47℃),及酸性溶液[磷酸缓冲液(pH4.0)、含有有机酸(60 mmol·L^(-1)柠檬酸、60 mmol·L^(-1)乳酸、80 mmol·L^(-1)乙酸)的磷酸缓冲液(pH4.0)]。另外,通过荧光定量RT-PCR技术分析了茶多酚诱导下铜绿假单胞菌胁迫相关基因的表达情况。研究发现,茶多酚能够显著诱导铜绿假单胞菌氧化胁迫相关基因kat B、sod M、ohr、lex A和rec N的表达,以及热激蛋白基因dnaK、groEL、htpG、grpE和groES的表达。这些胁迫相关基因的表达很可能在细菌交叉耐受性形成过程中起到重要作用。以上研究结果表明,虽然茶多酚作为天然食品添加剂具有较高的安全性,但在实际应用过程中应充分考虑茶多酚诱导细菌交叉耐受性所导致的潜在风险,以优化食品保鲜策略。

Cross-resistance induced by sublethal concentration oftea polyphenols(TP)to Pseudomonas aeruginosa was investigated.One-hour exposure of Pseudomonas aeruginosato 1mg·mL-1TP significantly increased the tolerance to multiple environmental stresses, including oxidant(1mmol·L-1H2O2), high temperature (47℃) andacid solutions[phosphate buffer (pH4.0),phosphate buffer (pH4.0) containing 60mmol·L-1citric acid, 60mmol·L-1 lactic acid and 80mmol·L-1acetic acid]. In addition,the effects of TP on expression levels of a few stress-related geneswere studiedby quantitative real-time RT-PCR analysis.It was observed that the expression levels of a few oxidativestress-related geneskat B,sod M,ohr,lex Aandrec Nwere up-regulated by TP, as well as someheat shock protein genes, includingdnaK,groEL,htpG,grpEandgroES.The expression ofthesegenes might play important roles in the development of stress cross-resistance.Although TP was considered to be safe as food preservatives,the underlyinghazardsassociated withcross-resistance inducedby TP should be taken into account in food technology.