Radiation-induced peroxidation of small unilamellar vesicles of phosphatidylcholine generated by sonication

2004 ◽  
Vol 82 (2) ◽  
pp. 153-160 ◽  
Author(s):  
H Vitrac ◽  
M Courrègelongue ◽  
M Couturier ◽  
F Collin ◽  
P Thérond ◽  
...  
Keyword(s):  
High Performance ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Oxidation Products ◽  
Fatty Acyl Chain ◽  
Radiation Doses ◽  
Structural Assignment ◽  
Radiation Induced ◽  
Sonication Technique

The present study was aimed at determining the peroxidation of model membranes constituted of liposomes of 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine (PLPC) submitted to hydroxyl free radicals (generated by γ-radiolysis) attack. Liposomes of PLPC were prepared using the sonication technique, and dynamic light-scattering (DLS) measurements allowed characterization of the liposomal dispersions. Irradiation damages in sonication-generated liposomes were assessed by monitoring several oxidation products, such as conjugated dienes (by means of UV–visible spectrophotometry) and hydroperoxides (using reverse phase high-performance liquid chromatography (HPLC) associated with chemiluminescence detection). It has been shown that three different families of hydroperoxides are formed: the first one (at low radiation doses) results from HO· attack on the linoleyl chain of PLPC, giving phosphatidylcholine hydroperoxides possessing a conjugated dienic structure; the two others (at high radiation doses) are obtained by the secondary HO· attack on the primary hydroperoxide family. The quantification of these products associated with the comparison of their radiation-dose-dependent formation has provided valuable information concerning the mechanisms of their formation. Analysis by HPLC – mass spectrometry has confirmed the presence of hydroperoxides and underlined various other products, like chain-shortened fragments and oxygenated derivatives of polyunsaturated sn-2 fatty acyl chain residues. Structural assignment proposals of some oxidation products have been proposed.Key words: radiolysis, phospholipids, peroxidation, hydroperoxides, liposomes.

scholarly journals Biophysical Characterization of a New Phospholipid Analogue with a Spin-Labeled Unsaturated Fatty Acyl Chain

2009 ◽  
Vol 96 (3) ◽  
pp. 1008-1015 ◽  
Author(s):  
Andreas Bunge ◽  
Anne-Katrin Windeck ◽  
Thomas Pomorski ◽  
Jürgen Schiller ◽  
Andreas Herrmann ◽  
...  
Keyword(s):  
Acyl Chain ◽  
Fatty Acyl ◽  
Fatty Acyl Chain ◽  
Biophysical Characterization

FTIR spectroscopy characterization of fatty-acyl-chain conjugates

2015 ◽  
Vol 408 (1) ◽  
pp. 319-326 ◽  
Author(s):  
Vladimir Bobroff ◽  
Cyril Rubio ◽  
Valérie Vigier ◽  
Cyril Petibois
Keyword(s):  
Ftir Spectroscopy ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Fatty Acyl Chain

Fatty acyl chain structure, orientational order, and the lipid phase transition in Acholeplasma laidlawii B membranes. A review of recent 19F nuclear magnetic resonance studies

1984 ◽  
Vol 62 (11) ◽  
pp. 1134-1150 ◽  
Author(s):  
P. M. Macdonald ◽  
B. D. Sykes ◽  
R. N. McElhaney
Keyword(s):  
Phase Transition ◽  
Fatty Acids ◽  
Nuclear Magnetic Resonance ◽  
Acyl Chain ◽  
Orientational Order ◽  
Membrane Lipid ◽  
Fatty Acyl ◽  
Fatty Acyl Chain ◽  
Lipid Phase ◽  
Lipid Phase Transition

The orientational order parameters of monofluoropalmitic acids biosynthetically incorporated into membranes of Acholeplasma laidlawii B in the presence of a large excess of a variety of structurally diverse fatty acids have been determined via 19F nuclear magnetic resonance (19F NMR) spectroscopy. It is demonstrated that these monofluoropalmitic acids are relatively nonperturbing membrane probes based upon physical (differential scanning calorimetry), biochemical (membrane lipid analysis), and biological (growth studies) criteria. 19F NMR is shown to convey the same qualitative and quantitative picture of membrane lipid order provided by 2H-NMR techniques and to be sensitive to the structural characteristics of the membrane fatty acyl chains, as well as to the lipid phase transition. Representatives of each naturally occurring class of fatty acyl chain structures, including straight-chain saturated, methyl-branched, monounsaturated, and alicyclic-ring-substituted fatty acids, were studied and the 19F-NMR order parameters were correlated with the lipid phase transitions (determined calorimetrically). The lipid phase transition was the prime determinant of overall orientational order regardless of fatty acid structure. Effects upon orientational order attributable to specific structural substituents were discernible, but were secondary to the effects of the lipid phase transition. In the gel state, relative overall order was directly proportional to the temperature of the particular lipid phase transition. Not only the overall order, but also the order profile across the membrane was sensitive to the presence of particular structural substituents. In particular, in the gel state specific fatty acyl structures demonstrated a characteristic disordering effect in the membrane order profile. These various observations can be merged to provide a unified picture of the manner in which fatty acyl chain chemistry modulates the physical state of membrane lipids.

scholarly journals The Role of Ceramide Metabolism and Signaling in the Regulation of Mitophagy and Cancer Therapy

Cancers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2475
Author(s):  
Megan Sheridan ◽  
Besim Ogretmen
Keyword(s):  
Cancer Therapy ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Fatty Acyl Chain ◽  
Cancer Cell Proliferation ◽  
Bioactive Lipids ◽  
Cellular Functions ◽  
Proliferation Response ◽  
Ceramide Synthases

Sphingolipids are bioactive lipids responsible for regulating diverse cellular functions such as proliferation, migration, senescence, and death. These lipids are characterized by a long-chain sphingosine backbone amide-linked to a fatty acyl chain with variable length. The length of the fatty acyl chain is determined by specific ceramide synthases, and this fatty acyl length also determines the sphingolipid’s specialized functions within the cell. One function in particular, the regulation of the selective autophagy of mitochondria, or mitophagy, is closely regulated by ceramide, a key regulatory sphingolipid. Mitophagy alterations have important implications for cancer cell proliferation, response to chemotherapeutics, and mitophagy-mediated cell death. This review will focus on the alterations of ceramide synthases in cancer and sphingolipid regulation of lethal mitophagy, concerning cancer therapy.

Effect of Acylglycerol Composition and Fatty Acyl Chain Length on Lipid Digestion in pH-Stat Digestion Model and SimulatedIn VitroDigestion Model

2015 ◽  
Vol 81 (2) ◽  
pp. C317-C323
Author(s):  
Jin F. Qi ◽  
Cai H. Jia ◽  
Jung A. Shin ◽  
Jeong M. Woo ◽  
Xiang Y. Wang ◽  
...  
Keyword(s):  
Chain Length ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Fatty Acyl Chain ◽  
Lipid Digestion ◽  
Acyl Chain Length ◽  
Ph Stat

scholarly journals Acyltransferase-mediated selection of the length of the fatty acyl chain and of the acylation site governs activation of bacterial RTX toxins

2020 ◽  
Vol 295 (28) ◽  
pp. 9268-9280 ◽  
Author(s):  
Adriana Osickova ◽  
Humaira Khaliq ◽  
Jiri Masin ◽  
David Jurnecka ◽  
Anna Sukova ◽  
...  
Keyword(s):  
Acyl Chain ◽  
Fatty Acyl ◽  
Biologically Active ◽  
Fatty Acyl Chain ◽  
Acyl Carrier Proteins ◽  
E Coli ◽  
Rtx Toxins ◽  
Wide Range ◽  
Lysine Residues ◽  
Acyl Chains

In a wide range of organisms, from bacteria to humans, numerous proteins have to be posttranslationally acylated to become biologically active. Bacterial repeats in toxin (RTX) cytolysins form a prominent group of proteins that are synthesized as inactive protoxins and undergo posttranslational acylation on ε-amino groups of two internal conserved lysine residues by co-expressed toxin-activating acyltransferases. Here, we investigated how the chemical nature, position, and number of bound acyl chains govern the activities of Bordetella pertussis adenylate cyclase toxin (CyaA), Escherichia coli α-hemolysin (HlyA), and Kingella kingae cytotoxin (RtxA). We found that the three protoxins are acylated in the same E. coli cell background by each of the CyaC, HlyC, and RtxC acyltransferases. We also noted that the acyltransferase selects from the bacterial pool of acyl–acyl carrier proteins (ACPs) an acyl chain of a specific length for covalent linkage to the protoxin. The acyltransferase also selects whether both or only one of two conserved lysine residues of the protoxin will be posttranslationally acylated. Functional assays revealed that RtxA has to be modified by 14-carbon fatty acyl chains to be biologically active, that HlyA remains active also when modified by 16-carbon acyl chains, and that CyaA is activated exclusively by 16-carbon acyl chains. These results suggest that the RTX toxin molecules are structurally adapted to the length of the acyl chains used for modification of their acylated lysine residue in the second, more conserved acylation site.

scholarly journals Ectopic expression of ceramide synthase 2 in neurons suppresses neurodegeneration induced by ceramide synthase 1 deficiency

2016 ◽  
Vol 113 (21) ◽  
pp. 5928-5933 ◽  
Author(s):  
Stefka D. Spassieva ◽  
Xiaojie Ji ◽  
Ye Liu ◽  
Kenneth Gable ◽  
Jacek Bielawski ◽  
...  
Keyword(s):  
Acyl Chain ◽  
Strong Association ◽  
Ectopic Expression ◽  
Fatty Acyl ◽  
Chemical Diversity ◽  
Fatty Acyl Chain ◽  
Length Variation ◽  
Ceramide Synthase ◽  
Hydrophobic Moiety

Sphingolipids exhibit extreme functional and chemical diversity that is in part determined by their hydrophobic moiety, ceramide. In mammals, the fatty acyl chain length variation of ceramides is determined by six (dihydro)ceramide synthase (CerS) isoforms. Previously, we and others showed that mutations in the major neuron-specific CerS1, which synthesizes 18-carbon fatty acyl (C18) ceramide, cause elevation of long-chain base (LCB) substrates and decrease in C18 ceramide and derivatives in the brain, leading to neurodegeneration in mice and myoclonus epilepsy with dementia in humans. Whether LCB elevation or C18 ceramide reduction leads to neurodegeneration is unclear. Here, we ectopically expressed CerS2, a nonneuronal CerS producing C22–C24 ceramides, in neurons of Cers1-deficient mice. Surprisingly, the Cers1 mutant pathology was almost completely suppressed. Because CerS2 cannot replenish C18 ceramide, the rescue is likely a result of LCB reduction. Consistent with this hypothesis, we found that only LCBs, the substrates common for all of the CerS isoforms, but not ceramides and complex sphingolipids, were restored to the wild-type levels in the Cers2-rescued Cers1 mutant mouse brains. Furthermore, LCBs induced neurite fragmentation in cultured neurons at concentrations corresponding to the elevated levels in the CerS1-deficient brain. The strong association of LCB levels with neuronal survival both in vivo and in vitro suggests high-level accumulation of LCBs is a possible underlying cause of the CerS1 deficiency-induced neuronal death.

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