Chloro-benzoquinones cause oxidative DNA damage through iron-mediated ROS production in Escherichia coli

Abstract

h i g h l i g h t sCBQs have genotoxicity and cytotoxicity in E. coli cells. CBQs exposure to E. coli cells led to intracellular substantial ROS production. The addition of Fe 2+ to the CBQs exposure system enhanced DNA oxidative damage.ROS scavengers and iron-chelators can partial protect from oxidative DNA damage. AhpCF, catalase E and catalase G protected E. coli from DNA damage corporately.a r t i c l e i n f o a b s t r a c tChloro-benzoquinones (CBQs) are a group of disinfection byproducts that are suspected to be potentially carcinogenic. Here, the mechanism of DNA damage caused by CBQs in the presence of ferrous ions was investigated in an Escherichia coli wild type M5 strain and a mutant L5 (ahpCF katEG mutant) strain that carried an enhanced green fluorescent protein reporter under the control of a SOS response gene (recA) promoter. All tested CBQs (including para-benzoquinone, 2-chloro-para-benzoquinone, and dichloro-para-benzoquinones with different substitutes) caused substantial oxidative DNA damage with EC 50 values in the micromolar range. Moreover, 2,5-dichloro-para-benzoquinone (2,5-DCBQ), a typical CBQ, caused substantial ROS production in E. coli mutant cells. And ROS scavengers provided partial protective effects on genotoxicity of 2,5-DCBQ to E. coli mutant cells. The addition of Fe 2+ to the 2,5-DCBQ exposure system caused an increase in DNA oxidative damage; iron-chelating agents could partially prevent these cells from DNA damage. Finally, intracellular AhpCF, catalase E, and catalase G were all found to play an important role in the survival of E. coli cells exposed to CBQs, as indicated by an increased sensitivity of the ahpCF katEG mutant L5 strain to treatment compared with wild type M5 cells. Taken together, these results suggest that CBQs cause oxidative DNA damage in E. coli cells through the participation of iron-mediated ROS production.

Spread of MCR-3 Colistin Resistance in China: An Epidemiological, Genomic and Mechanistic Study

“…All the E. coli strains in mid-log phase [OD600 = ~0.8] (Table S3) were divided into two equal fractions: one half acted as control, the remaining fraction was challenged with 4 μg/ml colistin for 0.5 h. The oxidant-sensitive dye used for ROS detection was 2′,7′- d i c hlorodihydro f luorescein d i a cetate (DCFH 2 DA, Sigma). The fluorescent images were captured with a Zeiss LSM 510 Meta confocal laser scanning microscope (100× oil immersion objective), in which the fluorescence of d i c hloro- f luorescein (DCF, an oxidation product of DCFH 2 DA) was excited by 488 nm, and resultant emission was detected at 530 nm [ 86 ].…”

Defining ICR-Mo, an intrinsic colistin resistance determinant from Moraxella osloensis

“…The oxidant sensor dye DCFH2-DA (i.e., 2′,7′-dichlorodihydrofluorescein diacetate, Sigma) was utilized to detect intra-cellular accumulation of reactive oxygen species (ROS). The fluorescent dichlorofluorescein (DCF), the oxidation product of DCFH2-DA, was visualized using a Zeiss LSM 510 Meta confocal laser scanning microscope [ 71 ]. Totally, four types of E .…”

Effect of photooxidative stress and mannitol on synthesis of OmpC-OmpF proteins of Escherichia coli in lake water

“…Sabbahi et al (2008) found that the survival of S. aureus under MB/light photooxidation conditions increased by about 27% in the presence of mannitol [37]. Chen et al (2015) shown that wild type M5 strain of E. coli and a mutant L5 (ahpCF katEG mutant) strain cause DNA damage by chloro-benzoquinones in the presence of ferric ions [38]. In the same study, it was shown that this damage is much reduced in the presence of mannitol and ascorbic acid, thus protecting mannitol from ROS.…”