PHOSPHOLIPID BIOSYNTHESIS AND SOLVENT TOLERANCE IN PSEUDOMONAS-PUTIDASTRAINS

The role of the cell envelope in the solvent tolerance mechanisms of P seudomonas putida was investigated. The responses of a solvent-toleran t strain, P. putida Idaho, and a solvent-sensitive strain, P. putida M W1200, were examined in terms of phospholipid content and composition and of phospholipid biosynthetic rate following exposure to a nonmetab olizable solvent, o-xylene. Following o-xylene exposure, P. putida MW1 200 exhibited a decrease in total phospholipid content. In contrast, P . putida Idaho demonstrated an increase in phospholipid content 1 to 6 h after exposure. Analysis of phospholipid biosynthesis showed P. put ida Idaho to have a higher basal rate of phospholipid synthesis than M W1200. This rate increased significantly following exposure to xylene. Both strains showed little significant turnover of phospholipid in th e absence of xylene. In the presence of xylene, both strains showed in creased phospholipid turnover. The rate of turnover was significantly greater in P. putida Idaho than in P. putida MW1200. These results sug gest that P. putida Idaho has a greater ability than the solvent-sensi tive strain MW1200 to repair damaged membranes through efficient turno ver and increased phospholipid biosynthesis.