Exposure of Pseudomonas aeruginosa to green tea polyphenols enhances the tolerance to various environmental stresses.
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.
College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310035, Zhejiang, China.
Xiaoxiang
X
Liu
Jianrong
J
Li
Yi
Y
Yang
Xiaoqiang
X
Chen
D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D028241:Camellia sinensis / Q000737:chemistry*; D002264:Carboxylic Acids / Q000633:toxicity; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D004361:Drug Tolerance; D000431:Ethanol / Q000633:toxicity; D005840:Gentian Violet / Q000633:toxicity; D016877:Oxidants / Q000633:toxicity; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D059808:Polyphenols / Q000302:isolation & purification / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D013312:Stress, Physiological
D000900:Anti-Bacterial Agents; D002264:Carboxylic Acids; D016877:Oxidants; D010936:Plant Extracts; D059808:Polyphenols; D000431:Ethanol; D005840:Gentian Violet