College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310035, Zhejiang, China.
World J Microbiol Biotechnol. 2012 Dec;28(12):3373-80. doi: 10.1007/s11274-012-1149-4. Epub 2012 Aug 17.
Green tea polyphenols (GTP) are widely used as food preservatives and are considered to be extremely safe. However, the bacterial response to GTP has not been well studied. Here we investigated whether short exposure of Pseudomonas aeruginosa to sub-lethal dose of GTP could lead to cross-resistance to some environmental stresses. One-hour exposure of P. aeruginosa to 1 mg/ml GTP significantly increased the tolerance to oxidants (2 mM H(2)O(2), 4 mM tert-butylhydroperoxide), low pH solution (pH 4.0) containing various organic acids (60 mM citric, acetic, propionic or lactic acid) and other stress conditions (47 °C, 25 % NaCl, 12 % ethanol and 150 μg/ml crystal violet). The development of H(2)O(2) tolerance in GTP-exposed cells was prevented by chloramphenicol, a well-known inhibitor of protein synthesis in prokaryotic cells. Furthermore, we observed significantly increased catalase activity after GTP exposure, suggesting that P. aeruginosa develops GTP-induced cross-resistance by increasing synthesis of protective protein. These observations raise concerns over the underlying risks associated with using GTP as food preservatives.
绿茶多酚（GTP）被广泛用作食品防腐剂，被认为是极其安全的。然而，细菌对 GTP 的反应尚未得到很好的研究。在这里，我们研究了短时间暴露于亚致死剂量的 GTP 是否会导致铜绿假单胞菌对一些环境应激的交叉耐药性。铜绿假单胞菌暴露于 1mg/ml GTP 1 小时显著增加了对氧化剂（2mM H₂O₂、4mM 叔丁基过氧化物）、含有各种有机酸（60mM 柠檬酸、醋酸、丙酸或乳酸）的低 pH 溶液（pH4.0）和其他应激条件（47°C、25%NaCl、12%乙醇和 150μg/ml 结晶紫）的耐受性。GTP 暴露细胞中 H₂O₂耐受性的发展被氯霉素所阻止，氯霉素是原核细胞中蛋白质合成的一种众所周知的抑制剂。此外，我们观察到 GTP 暴露后过氧化氢酶活性显著增加，这表明铜绿假单胞菌通过增加保护性蛋白的合成来产生 GTP 诱导的交叉耐药性。这些观察结果引起了人们对将 GTP 用作食品防腐剂所涉及的潜在风险的关注。
