Institute of Ecology and Genetics of Microorganisms, Ural Branch of the Russian Academy of Sciences, 13 Golev Street, 614081, Perm, Russia.
Perm State National Research University, 15 Bukirev Street, 614990, Perm, Russia.
Sci Rep. 2019 Jun 24;9(1):9159. doi: 10.1038/s41598-019-45732-9.
This study investigated the ability of rhodococci to biodegrade diclofenac (DCF), one of the polycyclic non-steroidal anti-inflammatory drugs (NSAIDs) most frequently detected in the environment. Rhodococcus ruber strain IEGM 346 capable of complete DCF biodegradation (50 µg/L) over 6 days was selected. It is distinguished by the ability to degrade DCF at high (50 mg/L) concentrations unlike other known biodegraders. The DCF decomposition process was accelerated by adding glucose and due to short-term cell adaptation to 5 µg/L DCF. The most typical responses to DCF exposure observed were the changed ζ-potential of bacterial cells; increased cell hydrophobicity and total cell lipid content; multi-cellular conglomerates formed; and the changed surface-to-volume ratio. The obtained findings are considered as mechanisms of rhodococcal adaptation and hence their increased resistance to toxic effects of this pharmaceutical pollutant. The proposed pathways of bacterial DCF metabolisation were described. The data confirming the C-N bond cleavage and aromatic ring opening in the DCF structure were obtained.
本研究考察了节杆菌属（Rhodococcus）降解双氯芬酸（DCF）的能力，DCF 是环境中最常检测到的一类多环非甾体抗炎药（NSAIDs）之一。选择了一株能够完全降解 DCF（50μg/L）的红球菌（Rhodococcus ruber）IEGM 346 菌株，该菌株在高浓度（50mg/L）下也具有降解 DCF 的能力，这与其他已知的生物降解菌不同。添加葡萄糖和通过短期细胞适应 5μg/L 的 DCF 可以加速 DCF 的分解过程。观察到的 DCF 暴露最典型的反应是细菌细胞ζ-电位的改变；细胞疏水性和总细胞脂质含量增加；形成多细胞聚集体；以及比表面积的变化。所得发现被认为是节杆菌属适应的机制，因此它们对这种药物污染物的毒性作用的抵抗力增强。描述了细菌 DCF 代谢的可能途径。获得了确认 DCF 结构中 C-N 键断裂和芳环开环的数据。
