Coordinated response of phospholipids and acyl components of membrane lipids in Pseudomonas putida A (ATCC 12633) under stress caused by cationic surfactants

HEREDIA R.M; BOERIS P.S.; BIAZUTTI, M.A. ; LOPÉZ G.A; PAULUCCI N.S; LUCCHESI G.I.

MICROBIOLOGY-UK

SOC GENERAL MICROBIOLOGY

Lugar: London; Año: 2014 vol. 160 p. 2618 - 2626

1350-0872

The present study assessed the role of membrane component of Pseudomonas putida A (ATCC 12633) under chemical stress condition originated by treatment with tetradecyltrimethylammonium bromide (TTAB), a cationic surfactant. We examined changes in fatty acid (FA) composition and in the fluidity of the membranes of cells exposed to TTAB at a specific point of growth as well as of cells growing with TTAB. The addition of 10 to 50 mg l-1 TTAB promoted an increase in the saturated/unsaturated ratio of fatty acid. By using fluorescence polarization techniques we found that TTAB exerted a fluidizing effect on P. putida membranes. However, a complete reversal of induced membrane fluidification was detected after 15 min of incubation with TTAB. Consistently, the proportion of unsaturated fatty acid was lower in TTAB treated cells with respect to non-treated cells. In presence of TTAB, the content of phosphatidylglycerol increased (120%) while cardiolipin decreased (60%). Analysis of fatty acid composition of P. putida showed that phosphatidylglycerol carried the major proportion of saturated fatty acid (89%) while cardiolipin carried an elevated proportion of unsaturated fatty acid (18%). The increase in phosphatidylglycerol and consequently in saturated fatty acid together with a decrease in cardiolipin content enables greater membrane resistance, reversing the fluidizing effect of TTAB. Therefore, results obtained in the present study point to changes in fatty acid profile as an adaptive response of P. putida cells to stress caused by cationic surfactant.