G. V. Smirnova, A. V. Tyulenev, N. G. Muzyka, L. V. Sutormina, O. N. Oktyabrsky
{"title":"Changes in the Activity of Antioxidant Systems of Escherichia coli under Phosphate Starvation","authors":"G. V. Smirnova, A. V. Tyulenev, N. G. Muzyka, L. V. Sutormina, O. N. Oktyabrsky","doi":"10.1134/s0026893323060171","DOIUrl":null,"url":null,"abstract":"<p><b>Abstract</b>—Changes in the activity of antioxidant systems in <i>Escherichia coli</i> during phosphate starvation have been studied. It is shown that starvation was accompanied by a decrease in the intensity of respiration, an increase in the rate of superoxide production, and a decrease in the level of ATP. Simultaneously, there was a decrease in H<sub>2</sub>O<sub>2</sub> in the medium and a significant increase in the expression of the <i>katG</i> and <i>katE</i> genes which encode the HPI and HPII catalases, respectively. At the same time, there was no drop in the membrane potential, which may indicate the retention of normal membrane activity in starving cells. It has been shown for the first time that the transition of <i>E. coli</i> to phosphate starvation is accompanied by significant changes in the status of glutathione. The most important of these are associated with a decrease in the level of reduced glutathione in the medium (GSH<sub>out</sub>) and with a simultaneous increase in its content in the cytoplasm (GSH<sub>in</sub>), as well as a shift in the GSH<sub>in</sub> to oxidized glutathione form (GSSG<sub>in</sub>) ratio towards reductive values, and GSH<sub>out</sub>/GSSG<sub>out</sub> towards oxidative values. Among the mutants used in the work, the <i>gor trxB</i> double mutant, which is deficient in the synthesis of glutathione reductase and thioredoxin reductase, showed the most pronounced distinctive features. Compared to the parental strain, this mutant showed a multiple higher expression of <i>katG</i>::<i>lacZ</i>, the highest level of oxidized intra- and extracellular glutathione, and, accordingly, the lowest GSH/GSSG ratio in both compartments. In general, the data we obtained indicate that during phosphate starvation the interaction of the glutathione redox-system and regulons that control protection against reactive oxygen species creates conditions that allow maintaining the concentration of ROS below the toxic level. As a result, phosphate-starved <i>E. coli</i> cells can maintain high viability for a long period of time, which allows them to quickly resume growth after the addition of phosphate.</p>","PeriodicalId":18734,"journal":{"name":"Molecular Biology","volume":null,"pages":null},"PeriodicalIF":1.5000,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Molecular Biology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1134/s0026893323060171","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract—Changes in the activity of antioxidant systems in Escherichia coli during phosphate starvation have been studied. It is shown that starvation was accompanied by a decrease in the intensity of respiration, an increase in the rate of superoxide production, and a decrease in the level of ATP. Simultaneously, there was a decrease in H2O2 in the medium and a significant increase in the expression of the katG and katE genes which encode the HPI and HPII catalases, respectively. At the same time, there was no drop in the membrane potential, which may indicate the retention of normal membrane activity in starving cells. It has been shown for the first time that the transition of E. coli to phosphate starvation is accompanied by significant changes in the status of glutathione. The most important of these are associated with a decrease in the level of reduced glutathione in the medium (GSHout) and with a simultaneous increase in its content in the cytoplasm (GSHin), as well as a shift in the GSHin to oxidized glutathione form (GSSGin) ratio towards reductive values, and GSHout/GSSGout towards oxidative values. Among the mutants used in the work, the gor trxB double mutant, which is deficient in the synthesis of glutathione reductase and thioredoxin reductase, showed the most pronounced distinctive features. Compared to the parental strain, this mutant showed a multiple higher expression of katG::lacZ, the highest level of oxidized intra- and extracellular glutathione, and, accordingly, the lowest GSH/GSSG ratio in both compartments. In general, the data we obtained indicate that during phosphate starvation the interaction of the glutathione redox-system and regulons that control protection against reactive oxygen species creates conditions that allow maintaining the concentration of ROS below the toxic level. As a result, phosphate-starved E. coli cells can maintain high viability for a long period of time, which allows them to quickly resume growth after the addition of phosphate.
期刊介绍：
Molecular Biology is an international peer reviewed journal that covers a wide scope of problems in molecular, cell and computational biology including genomics, proteomics, bioinformatics, molecular virology and immunology, molecular development biology, molecular evolution and related areals. Molecular Biology publishes reviews, experimental and theoretical works. Every year, the journal publishes special issues devoted to most rapidly developing branches of physical-chemical biology and to the most outstanding scientists.
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