Effects of exogenous sulfate on the chromium(VI) metabolism of chromium(VI)-resistant engineered strains

Xinglong Li; Qi Yin; Ruijia Gu; Mei Li; Jing Yan; Yuan Liu; Yanlun Qiu; Qunhua Bai; Yingli Li; Yan Ji; Jieying Gao; Hong Xiao

Ecotoxicology and Environmental Safety (Dec 2021)

Effects of exogenous sulfate on the chromium(VI) metabolism of chromium(VI)-resistant engineered strains

Xinglong Li,
Qi Yin,
Ruijia Gu,
Mei Li,
Jing Yan,
Yuan Liu,
Yanlun Qiu,
Qunhua Bai,
Yingli Li,
Yan Ji,
Jieying Gao,
Hong Xiao

Affiliations

Xinglong Li: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China
Qi Yin: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China
Ruijia Gu: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China; Center for Disease Control and Prevention of Fucheng District, No. 116 north section of Changhong Avenue, Fucheng District, Mianyang City 621000, PR China
Mei Li: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China
Jing Yan: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China
Yuan Liu: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China
Yanlun Qiu: Center for Disease Control and Prevention of Beibei District, No. 51 east Beixia Road, Chaoyang District, Chongqing 400700, PR China
Qunhua Bai: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China
Yingli Li: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China
Yan Ji: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China
Jieying Gao: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China
Hong Xiao: Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 61 Daxuecheng Middle Road, Shapingba District, Chongqing 401334, PR China; Corresponding author.

Journal volume & issue: Vol. 228
p. 112984

Abstract

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Objective: To explore the effects of exogenous sulfate on the efficiency of chromium(VI) metabolism of three chromium(VI)-resistant Escherichia coli strains (eChrA / eChrB / eChrAB) by adding chromium(VI)-resistance genes chrA and/or chrB, for better understanding and further application of these Cr(VI)-resistant strains in environmental and industrial chromium removal. Methods: Based on three engineered Cr(VI)-resistant strains exposed to different concentrations of sulfate: i) Evaluation of Cr(VI) metabolism characteristics, including the growth rate, the Cr(VI) tolerance, the removal, absorption and efflux capacity of Cr(VI); ii) Detection the expressions of Cr(VI) resistance-related genes (chrA and chrB), and sulfate channel protein-related genes (sbp, cysA, cysU and cysW genes) by RT-qPCR. Results: Exogenous sulfate enhanced the Cr(VI) tolerance and the removal rate of these three engineered Cr(VI)-resistant strains, and promoted their growth rate under Cr(VI) stress, while suppressed their absorption and efflux capacity. Under a certain sulfate concentration, the Cr(VI) tolerance, removal ability and efflux capacity of these three strains were ranked as follow: eChrAB > eChrA > eChrB, while ranked as eChrB > eChrA > eChrAB for the Cr(VI) absorption rate, respectively. Opposite to the Cr(VI) treatment, exogenous sulfate suppressed the transcription levels of the Cr(VI) resistance-related genes (chrA and chrB) with gradually increased concentrations, and reduced those of sulfate channel protein related genes (sbp,cysA, cysU and cysW) under the medium and high concentrations. Conclusion: Sulfate can enhance the Cr(VI) tolerance and growth of Cr(VI)-resistant strains, via inhibiting the Cr(VI) absorption and efflux in a concentration-dependent manner. The underlying mode of action might be the competition of transport channels between sulfate and Cr(VI), and the suppression of sulfate channel protein related genes expressions by exogenous sulfate. Our results demonstrated an appropriate supplication of exogenous sulfate could contribute to the Cr(VI) pollution management by genes chrA/chrB related Cr(VI)-resistant strains. Additionally, the engineered E. coli strain eChrAB showed more potential for the actual Cr(VI) pollution application than strain eChrA and eChrB.

Published in Ecotoxicology and Environmental Safety

ISSN: 0147-6513 (Print); 1090-2414 (Online)
Publisher: Elsevier
Country of publisher: United States
LCC subjects: Technology: Environmental technology. Sanitary engineering: Environmental pollution; Geography. Anthropology. Recreation: Environmental sciences
Website: https://www.journals.elsevier.com/ecotoxicology-and-environmental-safety

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