Modification of phospholipid composition inPseudomonas putidaA ATCC 12633 induced by contact with tetradecyltrimethylammonium

Abstract

Aims: The aim of this work was to establish if the response to tetradecyltrimethylammonium (TDTMA), a representative quaternary ammonium compound (QAC), involves changes in the phospholipid (PL) composition of Pseudomonas putida A ATCC 12633. Methods and Results: Pseudomonas putida was exposed to 50 mg l−1 of TDTMA for 15 min, and PL composition was analysed. With respect to control values, phosphatidic acid and phosphatidylglycerol increased by 140% and 120%, respectively; cardiolipin decreased about 60%. In TDTMA‐adapted bacteria, the most significant change was a 380% increase in phosphatidic acid. Accompanying this change was a 130% increase in phosphatidylglycerol and a 70% decrease in cardiolipin. The changes in adapted cells were reverted after two subcultures without biocide. Conclusions: Pseudomonas putida responded to TDTMA through quantitative changes in PLs with specific variations in the content of phosphatidic acid, phosphatidylglycerol and cardiolipin. These modifications indicated that these PLs are involved in cellular responses to QACs, utilizing phosphatidic acid principally to neutralize the high positive charge density given for the ammonium quaternary moiety from TDTMA. Significance and Impact of the Study: The changes in PL composition give a new insight about the response inflicted by Ps. putida when these bacteria are exposed to QACs.

Release of outer membrane vesicles in Pseudomonas putida as a response to stress caused by cationic surfactants

“…Similarly to results found by Tashiro et al (2011) when studying the OMVs of Pseudomonas aeruginosa, we observed that the OMVs produced by P. putida A (ATCC 12633) did not contain PE and that PG was the major glycerophospholipid detected (42.17 % of total PL; Table 1). Different facts indicated PG as the main component of the OMVs released by P. putida in the presence of TTAB: the sixfold increase (up to 120 %) in the content of PG (Table S1, available in the online Supplementary Material; Boeris et al, 2007Boeris et al, , 2009) and the fact that PG has been associated with the attainment of the proper curvature for the release of membrane vesicles (Tashiro et al, 2012).…”

“…The mode of action of QACs in bacteria relies on the interaction of the surfactant with the lipidic bilayer of the membrane, which leads to the loss of membrane integrity, disruption of transduction energy, inhibition of protein action and subsequent deleterious effects on growth and viability (McDonnell & Russell, 1999;McBain et al, 2004;Gilbert & Moore, 2005). Although the connection between QAC degradation and tolerance is not well known, we have shown that in P. putida A (ATCC 12633) the adaptive response and resistance to the bactericidal activity of the QACs TTAB involves a mechanism that initiates changes to membrane composition (Boeris et al, 2007(Boeris et al, , 2009Heredia et al, 2014). The addition of a non-lethal concentration of TTAB resulted in the immediate fluidification of P. putida A (ATCC 12633) cell membranes.…”

“…This behaviour was related to a decrease in the proportion of the unsaturated fatty acids (UFAs) that help to compensate the fluidizing effect of TTAB, and also to block the access of TTAB molecules within the membrane's interior. Also, when the cells were exposed to TTAB, the content of phosphatidylglycerol (PG) increased sixfold, and the levels of cardiolipin (CL), with its elevated proportion of UFAs (18.33 % of total UFAs), decreased up to 60 % (Boeris et al, 2007(Boeris et al, , 2009Heredia et al, 2014). Thus, the decrease in the content of UFAs, due to the reduction of CL levels, together with an increase of PG levels, with the major content of saturated fatty acids (SFAs), contributes to the tolerance of P. putida A (ATCC 12633) to the stress caused by TTAB (Heredia et al, 2014).…”

“…Lipid analysis. Lipids were extracted from the cells and vesicles following the method of Bligh & Dyer (1959); they were later separated using 1D TLC (silica gel HLF, 250 microns; Analtech) and 2D TLC was carried out, when necessary, to discard the co-migration of different lipids (Boeris et al, 2007). The separated lipids were detected with iodine vapours and identified based on comparison to purified standards purchased from Sigma.…”

The phosphatidylcholine synthase of Pseudomonas putida A ATCC 12633 is responsible for the synthesis of phosphatidylcholine, which acts as a temporary reservoir for Al3+

“…The phospholipid (PL) composition of Pseudomonas putida A ATCC 12633 cultivated under unstressed culture conditions is similar to that described for other fluorescent Pseudomonas species (Ramos et al, 1997;Albelo & Domenech 1997;Pinkart & White, 1997). However, in the presence of the quaternary ammonium compound tetradecyltrimethylammonium bromide (TTAB), P. putida A ATCC 12633 responds through quantitative changes in its PL composition, with specific variations in the content of phosphatidic acid (PA), PG and CL (Boeris et al, 2007). In addition, in P. putida A ATCC 12633 cells grown with TTAB and exposed to Al 3 Cl, an increase in PC was detected, which led us to propose a physiological role for PC as a temporary reservoir for available Al 3+ through the formation of Al 3+ : PC complexes (Boeris et al, 2009).…”