6 research outputs found
Cold dependence of fatty acid profile of different lipid structures of Listeria monocytogenes
Listeria monocytogenes membrane lipid fatty acids (FA) play a role in its cold adaptation. Our previous study indicated that in newly synthesized neutral lipids, from the early stage of the temperature response (3 days at 5°C), only the anteiso-15:0 FA was selectively increased. In this study we focus on several NL class comparisons. Cells of L. monocytogenes were grown until stationary phase at 30 and 5°C and the FA from 1.2 diglyceride (DG), 1.3 DG and free FA as well as NL (in bulk) from each culture were analysed by GC. At 30°C, L. monocytogenes showed a FA profile from 1.2 DG, 1.3 DG, free FA and NL, dominated by anteiso-15:0 percentages 28.4%, 45.1%, 30.4%, 45.2%, respectively. Also from the three first classes the ratio anteiso-15:0/anteiso- 17:0 FA averaged 2.0, but the ratio of branched chain FA to straight chain FA of each class was 1.2, 4.7 and 2.3, respectively. L. monocytogenes cold adaptation response was based singularly on the increase (×5.9, ×5.4, ×8.3 and ×7.3-fold) of the ratio anteiso-15:0/anteiso-17:0 FA for 1.2 DG, 1.3 DG, free FA and NL, respectively, in contrast to a negligible change of the ratio branched to straight chain FA. Using 1H-NMR analysis it was revealed that the % reduction of ratio variation [-CH 2-]/[- CH 3] at cold (4.65%) for the NL class of Listeria's fatty acyl chains reflected the increase of the ratio value branched-15:0/branched-17:0 FA that was determined by GC analysis (×6.1-fold). © 2004 Elsevier Ltd. All rights reserved
Determination of operator exposure levels to insecticide during bait applications in olive trees: Study of coverall performance and duration of application
Effect of cold temperature on the composition of different lipid classes of the foodborne pathogen Listeria monocytogenes: Focus on neutral lipids
In this work a thorough consideration of the membrane lipid composition of Listeria monocytogenes together with DSC analysis is described in order to estimate the biological importance of lipid changes during low-temperature adaptation. Furthermore, these studies provide comparative data for fatty acid changes for neutral, NL and polar lipids, PL separately. The cold adaptation (5°C) response of L. monocytogenes showed (i) an increase in the level of NL content (30%) among the total lipids, TL and (ii) that the increase (7-fold) in the anteiso-15:0/anteiso-17:0 fatty acid ratio, FAr, for cold NL was at variance with the ratio for TL and PL (about 10-fold). We correlated our findings with DSC studies on phase transition temperature (Tc), enthalpy difference (ΔH) and peak range of the transition for TL, PL, NL (from cultures at 30 and 5°C); The decrease of Tc (10.5°C) and ΔH (51%) for TL is a reflection of the decrease of Tc (11.5°C) and ΔH (56%) for PL. This large decrease is interpreted by the high (10-fold) increase of a-15:0/a-17:0 FAr of PL5°C. In NL the decrease of Tc (3°C) and of ΔH (42%) is interpreted by both adaptation mechanisms: the (lower) 7-fold increase of anteiso-15:0/anteiso-17:0 FAr and the NL percentage calculated from increased mass values. The peak range of TL5°C (from -15 to 25°C) is a reflection of the peak range of NL 5°C, which is unchanged, as is the peak range of NL 30°C. © 2005 Elsevier Ltd. All rights reserved
Coordinated regulation of cold-induced changes in fatty acids with cardiolipin and phosphatidylglycerol composition among phospholipid species for the food pathogen Listeria monocytogenes
We present here the structural identification of four phospholipid (Phl) classes in Listeria monocytogenes, the fatty acid (FA) composition for each individual Phl species, and a description of cold-induced FA changes. Cardiolipin (48.5%) and phosphatidylglycerol (18.1%) are dominated by anteiso-FA, and the previously recognized branched FA chain shortening by cold was observed singularly in these Phis. Phosploaminolipid (19.9%) and phosphatidylinositol, (9.1%) are significantly different, containing significant amounts of straight-chain FA. These findings are supported by nuclear magnetic resonance analysis. Copyright © 2008, American Society for Microbiology. All Rights Reserved
Coordinated Regulation of Cold-Induced Changes in Fatty Acids with Cardiolipin and Phosphatidylglycerol Composition among Phospholipid Species for the Food Pathogen Listeria monocytogenes▿†
We present here the structural identification of four phospholipid (Phl) classes in Listeria monocytogenes, the fatty acid (FA) composition for each individual Phl species, and a description of cold-induced FA changes. Cardiolipin (48.5%) and phosphatidylglycerol (18.1%) are dominated by anteiso-FA, and the previously recognized branched FA chain shortening by cold was observed singularly in these Phls. Phosploaminolipid (19.9%) and phosphatidylinositol, (9.1%) are significantly different, containing significant amounts of straight-chain FA. These findings are supported by nuclear magnetic resonance analysis