Introduction. Metal exposure is an important factor for inducing antibiotic resistance in bacteria. Dandelion extracts have been used for centuries in traditional Chinese and Native American medicine. Aim. We assessed the effects of dandelion water extracts and taraxasterol on heavy metal-induced antibiotic resistance in Escherichia coli as well as the underlying mechanisms. Methodology. Dandelion extracts were obtained through 4 h of boiling in distilled water. Bacterial growth was monitored with a spectrophotometer. Biochemical assays were performed to assess the activities and gene transcriptions of β-lactamase and acetyltransferase. Oxidative stress was determined using an oxidation-sensitive probe, H2DCFDA. Results. The present study demonstrated that higher concentrations of nickel (>5 µg ml−1), cadmium (>0.1 µg ml−1), arsenic (>0.1 µg ml−1) and copper (>5 µg ml−1) significantly inhibited the growth of E. coli . Lower concentrations of nickel (0.5 µg ml−1), cadmium (0.05 µg ml−1) and arsenic (0.05 µg ml−1) had no effect on bacterial growth, but helped the bacteria become resistant to two antibiotics, kanamycin and ampicillin. The addition of dandelion root extracts and taraxasterol significantly reversed the antibiotic resistance induced by these heavy metals. The supplements of antibiotics and cadmium generated synergistic effects on the activities of β-lactamase and acetyltransferase (two antibiotic resistance-related proteins), which were significantly blocked by either dandelion root extract or taraxasterol. In contrast, oxidative stress was not involved in the preventative roles of dandelion root extracts and taraxasterol in heavy metal-induced antibiotic resistance. Conclusion. This study suggests that heavy metals induce bacterial antibiotic resistance and dandelion root extracts and taraxasterol could be used to help reverse bacterial resistance to antibiotics.

中文翻译：

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蒲公英根提取物和蒲公英糖醇逆转重金属诱导的抗生素抗性。

介绍。金属暴露是诱导细菌产生抗生素抗性的重要因素。蒲公英提取物已在传统的中药和美洲原住民医学中使用了多个世纪。目标。我们评估了蒲公英水提物和蒲公英糖醇对大肠杆菌中重金属诱导的抗生素耐药性的影响以及潜在的机制。方法。通过在蒸馏水中煮沸4小时获得蒲公英提取物。用分光光度计监测细菌的生长。进行生化分析以评估β-内酰胺酶和乙酰转移酶的活性和基因转录。使用氧化敏感探针H 2 DCFDA确定氧化应激。 结果。本研究表明，较高浓度的镍（> 5 µg ml -1），镉（> 0.1 µg ml -1），砷（> 0.1 µg ml -1）和铜（> 5 µg ml -1）会显着抑制铜离子的产生。大肠杆菌的生长。较低浓度的镍（0.5 µg ml -1），镉（0.05 µg ml -1）和砷（0.05 µg ml -1 ）对细菌的生长没有影响，但有助于细菌对两种抗生素卡那霉素和氨苄青霉素产生抗药性。添加蒲公英根提取物和蒲公英糖醇可显着逆转这些重金属诱导的抗生素耐药性。补充抗生素和镉对β-内酰胺酶和乙酰转移酶（两种与抗生素抗性有关的蛋白质）的活性产生协同作用，这些活性被蒲公英根提取物或蒲公英醇显着阻断。相比之下，氧化应激并未参与蒲公英根提取物和酒石酸甾醇在重金属诱导的抗生素抗性中的预防作用。结论。 这项研究表明，重金属可诱导细菌对细菌产生抗药性，而蒲公英根提取物和酒石黄醇可用于帮助逆转细菌对抗生素的抗药性。