scholarly journals Head-Group Acylation of Chloroplast Membrane Lipids

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1273
Author(s):  
Yu Song ◽  
Zolian S. Zoong Lwe ◽  
Pallikonda Arachchige Dona Bashanee Vinusha Wickramasinghe ◽  
Ruth Welti
Keyword(s):  
Mass Spectrometry ◽  
Arabidopsis Thaliana ◽  
Abiotic Stresses ◽  
Membrane Lipids ◽  
Fatty Acyl ◽  
Head Group ◽  
Biological Functions ◽  
Biotic And Abiotic Stresses ◽  
Acyl Chains ◽  
The 1960S

Head group-acylated chloroplast lipids were discovered in the 1960s, but interest was renewed about 15 years ago with the discovery of Arabidopsides E and G, acylated monogalactosyldiacylglycerols with oxidized fatty acyl chains originally identified in Arabidopsis thaliana. Since then, plant biologists have applied the power of mass spectrometry to identify additional oxidized and non-oxidized chloroplast lipids and quantify their levels in response to biotic and abiotic stresses. The enzyme responsible for the head-group acylation of chloroplast lipids was identified as a cytosolic protein closely associated with the chloroplast outer membrane and christened acylated galactolipid-associated phospholipase 1 (AGAP1). Despite many advances, critical questions remain about the biological functions of AGAP1 and its head group-acylated products.

scholarly journals Leaf Lipid Alterations in Response to Heat Stress of Arabidopsis thaliana

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 845 ◽  
Author(s):  
Sunitha Shiva ◽  
Thilani Samarakoon ◽  
Kaleb A. Lowe ◽  
Charles Roach ◽  
Hieu Sy Vu ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
Elevated Temperatures ◽  
Membrane Lipids ◽  
Fatty Acyl ◽  
Head Group ◽  
Wild Type ◽  
Lipid Levels ◽  
Acyl Chains ◽  
Severe Heat Stress

In response to elevated temperatures, plants alter the activities of enzymes that affect lipid composition. While it has long been known that plant leaf membrane lipids become less unsaturated in response to heat, other changes, including polygalactosylation of galactolipids, head group acylation of galactolipids, increases in phosphatidic acid and triacylglycerols, and formation of sterol glucosides and acyl sterol glucosides, have been observed more recently. In this work, by measuring lipid levels with mass spectrometry, we confirm the previously observed changes in Arabidopsis thaliana leaf lipids under three heat stress regimens. Additionally, in response to heat, increased oxidation of the fatty acyl chains of leaf galactolipids, sulfoquinovosyldiacylglycerols, and phosphatidylglycerols, and incorporation of oxidized acyl chains into acylated monogalactosyldiacylglycerols are shown. We also observed increased levels of digalactosylmonoacylglycerols and monogalactosylmonoacylglycerols. The hypothesis that a defect in sterol glycosylation would adversely affect regrowth of plants after a severe heat stress regimen was tested, but differences between wild-type and sterol glycosylation-defective plants were not detected.

How do mechanosensitive channels sense membrane tension?

2016 ◽  
Vol 44 (4) ◽  
pp. 1019-1025 ◽  
Author(s):  
Tim Rasmussen
Keyword(s):  
Membrane Lipids ◽  
Osmotic Shock ◽  
Md Simulations ◽  
Fatty Acyl ◽  
Membrane Bilayer ◽  
Cross Sectional ◽  
Conducting Path ◽  
Lipid Chain ◽  
Acyl Chains

Mechanosensitive (MS) channels provide protection against hypo-osmotic shock in bacteria whereas eukaryotic MS channels fulfil a multitude of important functions beside osmoregulation. Interactions with the membrane lipids are responsible for the sensing of mechanical force for most known MS channels. It emerged recently that not only prokaryotic, but also eukaryotic, MS channels are able to directly sense the tension in the membrane bilayer without any additional cofactor. If the membrane is solely viewed as a continuous medium with specific anisotropic physical properties, the sensitivity towards tension changes can be explained as result of the hydrophobic coupling between membrane and transmembrane (TM) regions of the channel. The increased cross-sectional area of the MS channel in the active conformation and elastic deformations of the membrane close to the channel have been described as important factors. However, recent studies suggest that molecular interactions of lipids with the channels could play an important role in mechanosensation. Pockets in between TM helices were identified in the MS channel of small conductance (MscS) and YnaI that are filled with lipids. Less lipids are present in the open state of MscS than the closed according to MD simulations. Thus it was suggested that exclusion of lipid fatty acyl chains from these pockets, as a consequence of increased tension, would trigger gating. Similarly, in the eukaryotic MS channel TRAAK it was found that a lipid chain blocks the conducting path in the closed state. The role of these specific lipid interactions in mechanosensation are highlighted in this review.

Temperature-induced changes in lecithin model membranes detected by novel covalent spin-labelled phospholipids

1977 ◽  
Vol 55 (2) ◽  
pp. 173-185 ◽  
Author(s):  
L. Stuhne-Sekalec ◽  
N. Z. Stanacev
Keyword(s):  
Transition Temperature ◽  
Fatty Acyl ◽  
Model Membranes ◽  
Head Group ◽  
Polar Head Group ◽  
Polar Group ◽  
Conformational Isomers ◽  
Hydrocarbon Chains ◽  
Acyl Chains ◽  
Induced Changes

Several spin-labelled phospholipids carrying covalently bound 5-doxylstearic acid (2-(3-carboxydecyl)-2-hexyl-4,4-dimethyl-3-oxazolidinoxyl) were intercalated in liposomes of saturated and unsaturated lecithins. Temperature-induced changes of these liposomes, detected by the spin-labelled phospholipids, were found to be in agreement with the previously described transitions of hydrocarbon chains of host lecithins detected by different probes and different techniques, establishing that spin-labelled phosopholipids are sensitive probes for the detection of temperature-induced changes in lecithin model membranes. In addition to the detection of already-known transitions in lecithin liposomes, the coexistence of two distinctly different environments was observed above the characteristic transition temperature. This phenomenon was tentatively attributed to the influence of the lecithin polar group on the fluidity of fatty acyl chains near the polar group. Combined with other results from the literature, the coexistence of two environments could be associated with the coexistence of two conformational isomers of lecithin, differing in the orientation of the polar head group with respect to the plane of bilayer. These findings have been discussed in view of the present state of knowledge regarding temperature-induced changes in model membranes.

scholarly journals Lipid conformation in model membranes and biological membranes

1980 ◽  
Vol 13 (1) ◽  
pp. 19-61 ◽  
Author(s):  
Joachim Seelig ◽  
Anna Seelig
Keyword(s):  
Liquid Crystalline ◽  
Double Helix ◽  
Liquid Paraffin ◽  
Biological Membranes ◽  
Fatty Acyl ◽  
Head Group ◽  
Exact Nature ◽  
Polar Head Group ◽  
Acyl Chains ◽  
Lipid Conformation

Protein molecules in solution or in protein crystals are characterized by rather well-defined structures in which α-helical regions, β-pleated sheets, etc., are the key features. Likewise, the double helix of nucleic acids has almost become the trademark of molecular biology as such. By contrast, the structural analysis of lipids has progressed at a relatively slow pace. The early X-ray diffraction studies by V. Luzzati and others firmly established the fact that the lipids in biological membranes are predominantly organized in bilayer structures (Luzzati, 1968). V. Luzzati was also the first to emphasize the liquid-like conformation of the hydrocarbon chains, similar to that of a liquid paraffin, yet with the average orientation of the chains perpendicular to the lipid–water interface. This liquid–crystalline bilayer is generally observed in lipid–water systems at sufficiently high temperature and water content, as well as in intact biological membranes under physiological conditions (Luzzati & Husson, 1962; Luzzati, 1968; Tardieu, Luzzati & Reman, 1973; Engelman, 1971; Shipley, 1973). In combination with thermodynamic and other spectroscopic observations these investigations culminated in the formulation of the fluid mosaic model of biological membranes (cf. Singer, 1971). However, within the limits of this model the exact nature of lipid conformation and dynamics was immaterial, the lipids were simply pictured as circles with two squiggly lines representing the polar head group and the fatty acyl chains, respectively. No attempt was made to incorporate the well-established chemical structure into this picture. Similarly, membrane proteins were visualized as smooth rotational ellipsoids disregarding the possibility that protruding amino acid side-chains and irregularities of the backbone folding may create a rather rugged protein surface.

Structural Characterization of Phosphatidylcholines by Atmospheric Pressure Photoionization Mass Spectrometry

2005 ◽  
Vol 11 (4) ◽  
pp. 409-417 ◽  
Author(s):  
Arnaud Delobel ◽  
David Touboul ◽  
Olivier Laprévote
Keyword(s):  
Mass Spectrometry ◽  
Structural Analysis ◽  
Atmospheric Pressure ◽  
Fatty Acyl ◽  
Ionization Mechanism ◽  
Atmospheric Pressure Photoionization ◽  
Photoionization Mass Spectrometry ◽  
Fragment Ions ◽  
Acyl Chains

The potential of atmospheric pressure photoionization was investigated for the structural analysis of phosphatidylcholine lipids (PCs). [M+H]+ ions of high abundance were obtained, along with several fragment ions. Three of these dissociation products corresponded to quite unusual fragmentation pathways but allowed the determination of both the nature and the position on the glycerol backbone ( sn-1 or sn-2) of the fatty acyl chains. The loss of a methyl group from the choline head was also observed. These results suggest a complex ionization mechanism in atmospheric pressure photoionization. However, this method proved to be very powerful for the rapid structural analysis of PC species without using tandem mass spectrometry experiments.

scholarly journals Serendipita indica changes host sugar and defense status in Arabidopsis thaliana: cooperation or exploitation?

Planta ◽  
2021 ◽  
Vol 253 (3) ◽  
Author(s):  
Michael W. Opitz ◽  
Roshanak Daneshkhah ◽  
Cindy Lorenz ◽  
Roland Ludwig ◽  
Siegrid Steinkellner ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Endophytic Fungus ◽  
Abiotic Stresses ◽  
Root Colonization ◽  
Growth Promotion ◽  
Sugar Metabolism ◽  
Defense Responses ◽  
Marker Genes ◽  
Wild Type ◽  
Biotic And Abiotic Stresses

Abstract Main conclusion Manipulation of sugar metabolism upon S. indica root colonization triggers changes in sugar pools and defense responses in A. thaliana. Abstract Serendipita indica is an endophytic fungus that establishes mutualistic relationships with many different plants including important crops as well as the model plant A. thaliana. Successful root colonization typically results in growth promotion and enhanced tolerance against various biotic and abiotic stresses. The fungus delivers phosphorus to the host and receives in exchange carbohydrates. There are hints that S. indica prefers hexoses, glucose, and fructose, products of saccharose cleavage driven by invertases (INVs) and sucrose synthases (SUSs). Carbohydrate metabolism in this interaction, however, remains still widely unexplored. Therefore, in this work, the sugar pools as well as the expression of SUSs and cytosolic INVs in plants colonized by S. indica were analyzed. Using sus1/2/3/4 and cinv1/2 mutants the importance of these genes for the induction of growth promotion and proper root colonization was demonstrated. Furthermore, the expression of several defense-related marker genes in both multiple mutants in comparison to the wild-type plants was determined. Our results show that in colonized A. thaliana plants S. indica manipulates the sugar metabolism by altering the expression of host’s INV and SUS and modulates both the sugar pools and plant defense in its favor. We conclude that the interaction A. thaliana–S. indica is a balancing act between cooperation and exploitation, in which sugar metabolism plays a crucial role. Small changes in this mechanism can lead to severe disruption resulting in the lack of growth promotion or altered colonization rate.

scholarly journals Analysis of Phospholipids, Lysophospholipids, and Their Linked Fatty Acyl Chains in Yellow Lupin Seeds (Lupinus luteus L.) by Liquid Chromatography and Tandem Mass Spectrometry

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 805 ◽  
Author(s):  
Cosima Damiana Calvano ◽  
Mariachiara Bianco ◽  
Giovanni Ventura ◽  
Ilario Losito ◽  
Francesco Palmisano ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Fatty Acyl ◽  
Negative Ion ◽  
Lupinus Luteus ◽  
Tandem Mass ◽  
Fragmentation Pattern ◽  
Yellow Lupin ◽  
Acyl Chains

Hydrophilic interaction liquid chromatography (HILIC) and electrospray ionization (ESI) coupled to either Fourier-transform (FT) orbital-trap or linear ion-trap tandem mass spectrometry (LIT-MS/MS) was used to characterize the phospholipidome of yellow lupin (Lupinus luteus) seeds. Phosphatidylcholines (PC) were the most abundant species (41 ± 6%), which were followed by lyso-forms LPC (30 ± 11%), phosphatidylethanolamines (PE, 13 ± 4%), phosphatidylglycerols (PG, 5.1 ± 1.7%), phosphatidic acids (PA, 4.9 ± 1.8%), phosphatidylinositols (PI, 4.7 ± 1.1%), and LPE (1.2 ± 0.5%). The occurrence of both isomeric forms of several LPC and LPE was inferred by a well-defined fragmentation pattern observed in negative ion mode. An unprecedented characterization of more than 200 polar lipids including 52 PC, 42 PE, 42 PA, 35 PG, 16 LPC, 13 LPE, and 10 PI, is reported. The most abundant fatty acids (FA) as esterified acyl chains in PL were 18:1 (oleic), 18:2 (linoleic), 16:0 (palmitic), and 18:3 (linolenic) with relatively high contents of long fatty acyl chains such as 22:0 (behenic), 24:0 (lignoceric), 20:1 (gondoic), and 22:1 (erucic). Their occurrence was confirmed by reversed-phase (RP) LC-ESI-FTMS analysis of a chemically hydrolyzed sample extract in acid conditions at 100 °C for 45 min.

Phospholipid composition of several clinically relevant Corynebacterium species as determined by mass spectrometry: an unusual fatty acyl moiety is present in inositol-containing phospholipids of Corynebacterium urealyticum

Microbiology ◽  
2003 ◽  
Vol 149 (7) ◽  
pp. 1675-1685 ◽  
Author(s):  
Genoveva Yagüe ◽  
Manuel Segovia ◽  
Pedro L. Valero-Guillén
Keyword(s):  
Mass Spectrometry ◽  
Phospholipid Composition ◽  
Fatty Acyl ◽  
Mass Spectrometry Data ◽  
Acyl Moiety ◽  
Fatty Acyl Moiety ◽  
Acyl Chains ◽  
Minor Phospholipid ◽  
Esi Mass Spectrometry ◽  
Corynebacterium Urealyticum

A comparative study on phospholipids of Corynebacterium amycolatum, Corynebacterium jeikeium and Corynebacterium urealyticum was carried out using fast-atom bombardment (FAB) and electrospray ionization (ESI) mass spectrometry. Data obtained indicate the presence of acylphosphatidylglycerol (APG), diphosphatidylglycerol, phosphatidylglycerol (PG), phosphatidylinositol (PI) and triacylphosphatidylinositol dimannosides (Ac3PIM2) in these bacteria. In general, octadecenoyl and hexadecanoyl fatty acyl moieties predominated in phospholipids of C. amycolatum, whereas high levels of hexadecenoyl were found in C. jeikeium and C. urealyticum. Mass spectra from purified APG and PG indicated that the sn-1 position of the glycerol was occupied by octadecenoyl in the three species studied. Notably, several major molecular species of PI and Ac3PIM2 from C. urealyticum contained significant amounts of a moiety identified as 10-methyleneoctadecanoyl, located at the sn-1 position of these molecules. On the other hand, multiantibiotic resistant and susceptible strains of C. amycolatum differed in several minor phospholipid fatty acids of 19 carbon atoms, identified as 10-methyloctadecenoic, 10-methyloctadecanoic (tuberculostearic acid) and 10-methyleneoctadecanoic. The results demonstrate an overall similarity among the phospholipids of the different species studied but also significant differences related to the acyl chains of the glycerol moiety of these compounds, notably the high levels of an unusual fatty acyl moiety in inositol-containing phospholipids of C. urealyticum.

scholarly journals Dynamic modulation of mitochondrial inner-membrane lipids in rat heart by dietary fat

1981 ◽  
Vol 193 (1) ◽  
pp. 155-167 ◽  
Author(s):  
S M Innis ◽  
M T Clandinin
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Dietary Fat ◽  
Rapeseed Oil ◽  
Membrane Lipids ◽  
Fatty Acyl ◽  
Soya Bean ◽  
Inner Membrane ◽  
Acyl Chains

A novel longitudinal feeding design was used to investigate the controlling influence of dietary fatty acids on the dynamic incorporation of fatty-acyl chains into phosphatidylcholine, phosphatidylethanolamine and cardiolipin in inner membrane of cardiac mitochondria. Rats were fed a polyunsaturated-fatty-acid-rich oil (soya-bean oil) for 12 days, crossed-over to a monounsaturated-fatty-acid-rich oil (rapeseed oil) for the next 11 days, then returned to soya-bean oil for 11 more days. Additional rats were fed either soya-bean oil or rapeseed oil only throughout. Rats were killed serially. Regression analysis was used to represent longitudinal flux in membrane lipid fatty-acid composition occurring with change in dietary fat. The fatty-acid composition of phosphatidylcholine, phosphatidylethanolamine and cardiolipin was influenced by dietary oil in a reversible way. Maximal diet influence was achieved in the 11-day cross-over period. Soya-bean oil to rapeseed oil cross-over caused the fatty-acid composition of phosphatidylcholine, phosphatidylethanolamine and cardiolipin to resemble that of rats fed rapeseed oil only. These changes were reversed by crossing back to soya-bean oil, indicating the dynamic state and short half-life of membrane phospholipid fatty-acyl chains. This report demonstrates for the first time in the whole animal fed diets adequate in all nutrients that subcellular membrane lipids rapidly respond to change in dietary fatty-acid balance. The system may be used to assess in vivo the significance of dietary fat in determining membrane physicochemical properties and biochemical functions.

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