Physiological role of phosphatidylcholine in the Pseudomonas putida A ATCC 12633 response to tetradecyltrimethylammonium bromide and aluminium

Aims: To evaluate the effect of tetradecyltrimethylammonium bromide (TTAB) and aluminium stresses on the phospholipid (PL) composition of Pseudomonas putida A ATCC 12633. Methods and Results: Pseudomonas putida were grown with TTAB in the presence or absence of AlCl3, and the PL composition was analysed. The presence of TTAB resulted in an increase in phosphatidylglycerol and phosphatidic acid levels (6- and 20-fold, respectively) with respect to the levels in cells grown without the surfactant. With AlCl3, phosphatidylcholine (PC) increased (threefold) and cell-free extracts contained approximately threefold more phosphatidylcholine synthase activities than extracts without AlCl3, indicating that the PC level is dependent upon activation of this enzyme. Conclusions: The negative charges of the headgroups of PL are the primary membrane-associated factors for the response to TTAB. PC are involved in cellular responses to binding Al<SU3+</SU and should be viewed as a temporary reservoir of available Al<SU3+</SU to allow a more efficient utilization of TTAB by Ps. putida. Significance and Impact of the Study: The changes in the PL of Ps. putida in the presence of TTAB and AlCl3 indicate that different responses are utilized by bacteria to maintain optimal PL composition in the presence of such environmental pollutants.