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Fatty acid biosynthesis is involved in solvent tolerance in Pseudomonas putida DOT‐T1E
Author(s) -
Segura Ana,
Duque Estrella,
Rojas Antonia,
Godoy Patricia,
Delgado Antonio,
Hurtado Ana,
E. Cronan John,
Ramos JuanLuis
Publication year - 2004
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2004.00578.x
Subject(s) - efflux , pseudomonas putida , biology , mutant , biochemistry , phospholipid , solvent , fatty acid , strain (injury) , toluene , membrane , chemistry , gene , organic chemistry , anatomy
Summary The unusual tolerance of Pseudomonas putida DOT‐T1E to toluene is based on the extrusion of this solvent by constitutive and inducible efflux pumps and rigidification of its membranes via phospholipid alterations. Pseudomonas putida DOT‐T1E‐109 is a solvent‐sensitive mutant. Mutant cells were less efficient in solvent extrusion than the wild‐type cells, as shown by the limited efflux of 14 C‐1,2,4‐trichlorobenzene from the cell membranes, despite the fact that the efflux pumps are overexpressed as a result of increased expression of the ttgDEF and ttgGHI efflux pump operons. This limitation could be the result of alterations in the outer membrane because the mutant cells released more β‐lactamase to the external medium than the wild‐type cells. The mutant P. putida DOT‐T1E‐109 showed negligible synthesis of fatty acids in the presence of sublethal concentrations of toluene as revealed by analysis of 13 CH 3 ‐ 13 COOH incorporation into fatty acids. In contrast, the mutant strain in the absence of solvents, and the wild‐type strain, both in the presence and in the absence of toluene, incorporated 13 CH 3 ‐ 13 COOH at a high rate into de novo synthesized lipids. The mutation in P. putida DOT‐T1E‐109 increases sensitivity to the solvent because of a limited efflux of the solvent from the cell membranes with the concomitant inhibition of fatty acid biosynthesis.