Abstract
Water-immiscible organic solvents can be toxic to microorganisms. The tolerance levels differ among strains of Escherichia coli, suggesting that the organic solvent tolerance level is strain specific and determined genetically. We constructed several mutants from E. coli, of which the organic solvent tolerance levels were improved. The mutants were defective in the marR gene encoding a repressor protein for the mar operon that is responsible for environmental stress factors. High expression of stress-responsive genes, soxS, marA, and robA, elevated organic solvent tolerance levels of several strains of E. coli. These genes code for DNA-binding proteins that are transcriptional activators belonging to the AraC subfamily with the helix-turn-helix motif. It was shown that expression of the AcrAB-TolC system, a major efflux pump in E. coli, was positively regulated by the proteins. This system was highly expressed in the organic solvent-tolerant mutants. Strains defective in one of the genes, acrA, acrB, or tolC, were remarkably sensitive to organic solvents.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
