Improvement of organic solvent tolerance level of Escherichia coli by overexpression of stress-responsive genes

Extremophiles ◽  
1998 ◽  
Vol 2 (3) ◽  
pp. 239-248 ◽  
Author(s):  
Rikizo Aonoa
Keyword(s):  
Escherichia Coli ◽  
Organic Solvent ◽  
Solvent Tolerance ◽  
Organic Solvent Tolerance ◽  
Tolerance Level ◽  
Stress Responsive Genes

scholarly journals Involvement of Outer Membrane Protein TolC, a Possible Member of the mar-sox Regulon, in Maintenance and Improvement of Organic Solvent Tolerance of Escherichia coli K-12

1998 ◽  
Vol 180 (4) ◽  
pp. 938-944 ◽  
Author(s):  
Rikizo Aono ◽  
Norihiko Tsukagoshi ◽  
Mami Yamamoto
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Organic Solvent ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Solvent Tolerance ◽  
Organic Solvent Tolerance ◽  
Tolerance Level ◽  
Inner Membrane Protein ◽  
K 12

ABSTRACT Escherichia coli mutants with improved organic solvent tolerance levels showed high levels of outer membrane protein TolC and inner membrane protein AcrA. The TolC level was regulated positively by MarA, Rob, or SoxS. A possible mar-rob-sox box sequence was found upstream of the tolC gene. These findings suggest that tolC is a member of the mar-sox regulon responsive to stress conditions. When a defective tolC gene was transferred to n-hexane- or cyclohexane-tolerant strains by P1 transduction, the organic solvent tolerance level was lowered dramatically to the decane-tolerant and nonane-sensitive level. The tolerance level was restored by transformation of the transductants with a wild-type tolC gene. Therefore, it is evident that TolC is essential for E. coli to maintain organic solvent tolerance.

scholarly journals Organic Solvent Tolerance of Escherichia coli Is Independent of OmpF Levels in the Membrane

1999 ◽  
Vol 65 (1) ◽  
pp. 294-296 ◽  
Author(s):  
Hiroyuki Asako ◽  
Kei Kobayashi ◽  
Rikizo Aono
Keyword(s):  
Escherichia Coli ◽  
Organic Solvent ◽  
Solvent Tolerance ◽  
Organic Solvent Tolerance ◽  
E Coli ◽  
Nacl Concentration ◽  
Responsive Gene

ABSTRACT The organic solvent tolerance of Escherichia coli was measured under conditions in which OmpF levels were controlled by various means as follows: alteration of NaCl concentration in the medium, transformation with a stress-responsive gene (marA,robA, or soxS), or disruption of theompF gene. It was shown that solvent tolerance of E. coli did not depend upon OmpF levels in the membrane.

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