title: Osmotolerance in Escherichia coli Is Improved by Activation of Copper Efflux Genes or Supplementation with Sulfur-Containing Amino Acids.
abstract: Improvement in the osmotolerance ofEscherichia coliis essential for the production of high titers of various bioproducts. In this work, acusSmutation that was identified in the previously constructed high-succinate-producingE. colistrain HX024 was investigated for its effect on osmotolerance. CusS is part of the two-component system CusSR that protects cells from Ag(I) and Cu(I) toxicity. ChangingcusSfrom strain HX024 back to its original sequence led to a 24% decrease in cell mass and succinate titer under osmotic stress (12% glucose). When cultivated with a high initial glucose concentration (12%), introduction of thecusSmutation into parental strain Suc-T110 led to a 21% increase in cell mass and a 40% increase in succinate titer. When the medium was supplemented with 30 g/liter disodium succinate, thecusSmutation led to a 120% increase in cell mass and a 492% increase in succinate titer. Introducing thecusSmutation into the wild-type strain ATCC 8739 led to increases in cell mass of 87% with 20% glucose and 36% using 30 g/liter disodium succinate. ThecusSmutation increased the expression ofcusCFBA, and gene expression levels were found to be positively related to osmotolerance abilities. Because high osmotic stress has been associated with deleterious accumulation of Cu(I) in the periplasm, activation of CusCFBA may alleviate this effect by transporting Cu(I) out of the cells. This hypothesis was confirmed by supplementing sulfur-containing amino acids that can chelate Cu(I). Adding methionine or cysteine to the medium increased the osmotolerance ofE. coliunder anaerobic conditions.IMPORTANCEIn this work, an activating Cus copper efflux system was found to increase the osmotolerance ofE. coliIn addition, new osmoprotectants were identified. Supplementation with methionine or cysteine led to an increase in osmotolerance ofE. coliunder anaerobic conditions. These new strategies for improving osmotolerance will be useful for improving the production of chemicals in industrial bioprocesses.
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Mengyong
authors.initials: M
authors.lastname: Xiao
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Xinna
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Feiyu
authors.initials: F
authors.lastname: Fan
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Xu
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Jinlei
authors.initials: J
authors.lastname: Tang
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Yanhe
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China zhang_xl@tib.cas.cn.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Xueli
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000494:pharmacology*; D000693:Anaerobiosis; D001692:Biological Transport; D002614:Chelating Agents; D003300:Copper / Q000378:metabolism*; D003545:Cysteine / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D008715:Methionine / Q000494:pharmacology; D009154:Mutation; D009997:Osmotic Pressure; D019897:Periplasm / Q000737:chemistry / Q000378:metabolism; D019802:Succinic Acid / Q000378:metabolism / Q000494:pharmacology; D013455:Sulfur / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics
chemical_list: D000596:Amino Acids; D002614:Chelating Agents; C000622714:CusR protein, E coli; D029968:Escherichia coli Proteins; D015534:Trans-Activators; D013455:Sulfur; D003300:Copper; D019802:Succinic Acid; D008715:Methionine; D005947:Glucose; D003545:Cysteine
keywords: Cu(I); CusS; Escherichia coli; copper efflux; methionine; osmotolerance