Evaluation of possible mechanisms of phorbol ester stimulation of phosphatidylcholine synthesis in HeLa cells

1985 ◽  
Vol 63 (2) ◽  
pp. 145-151 ◽  
Author(s):  
H. W. Cook ◽  
D. E. Vance
Keyword(s):  
Fatty Acids ◽  
Phorbol Ester ◽  
Hela Cells ◽  
Phorbol Esters ◽  
Neutral Lipids ◽  
Cellular Fatty Acid ◽  
Fatty Acyl ◽  
Ctp:Phosphocholine Cytidylyltransferase ◽  
Intracellular Release ◽  
Acyl Chains

Phorbol esters, including 12-O-tetradecanoylphorbol-13-acetate (TPA) and 12,13-dibutyrylphorbol acetate, markedly stimulate the synthesis of phosphatidylcholine (PC) and the activity of CTP:phosphocholine cytidylyltransferase (CT) in cultured HeLa cells. Two possible mechanisms whereby the phorbol esters stimulated PC biosynthesis were investigated. One consideration was that phorbol esters may induce the release of fatty acyl chains from endogenous complex lipids; increased fatty acids or fatty acyl-CoAs could cause the translocation of CT from cytosol to microsomes and thereby increase the activity of the rate-limiting enzyme in PC synthesis. In HeLa cells prelabeled with [3H]oleate or [3H]arachidonate, phorbol ester treatment increased the redistribution of arachidonate in phospholipids and neutral lipids and release of label to the medium, but there was little effect on the cellular fatty acid pools with either of the labeled fatty acids or of the phorbol esters. A second possibility was that protein kinase C (PKC), a receptor for phorbol esters, might be involved in activation of CT activity. TPA stimulated the phosphorylation of cytosolic proteins of HeLa cells more than twofold during a 10- or 60-min incubation with 32Pi. However, an approximate sixfold purified preparation of PKC from rat brain did not stimulate the activity of partially purified (12- to 15-fold) CT; a slight inhibition, dependent on ATP but independent of Ca2+ and diolein, was observed. Our results suggest that intracellular release of free fatty acids or direct phosphorylation of CT by PKC probably do not account for the observed levels of stimulation by phorbol esters. Other possible mechanisms are discussed.

scholarly journals Biodiesel Production from Oleaginous Fungi

2012 ◽  
Vol 6 (1) ◽  
pp. 43-49 ◽  
Author(s):  
K Ravikumar ◽  
J Dakshayini ◽  
ST Girisha
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Palmitic Acid ◽  
Neutral Lipids ◽  
Fatty Acyl ◽  
Ethyl Esters ◽  
Biodiesel Production ◽  
Sudan Black B ◽  
Oleaginous Fungi ◽  
Micro Organisms

Biodiesel involves the mixture of fatty acyl methyl/ethyl esters, produced from transesterification neutral lipids and if the origin of the source is from oleaginous micro organisms, then it is termed as micro diesel. In the present work, aiming to exploit fungi for biodiesel production, 12 fungal isolates were screened for lipid content by Sudan Black B staining method. Among 12 isolates, lipid rich five species viz, Mortierella alpina , M.ramanianna, M.vinancea, M.hyalina and M.verticella have been taken for fatty acids analysis by spectrophotometry, which revealed that the amount of free fatty acids were ranged from highest in M.alpina 35 ?moles of Oleic acid , 25 ?moles of Palmitic acid and 14 ?moles of Myristic acids to lower as much as 21 ?moles of Oleic acid , 18 ?moles of Palmitic acid and 16 ?moles of Myristic acids respectively in M.ramanianna. DOI: http://dx.doi.org/10.3126/ijls.v6i1.5721

scholarly journals Biochemical studies on cell fusion. I. Lipid composition of fusion-resistant cells.

1985 ◽  
Vol 101 (4) ◽  
pp. 1578-1590 ◽  
Author(s):  
D S Roos ◽  
P W Choppin
Keyword(s):  
Lipid Composition ◽  
Neutral Lipids ◽  
Mutant Cell ◽  
Ether Lipid ◽  
Resistant Cell ◽  
Fatty Acyl ◽  
Resistant Cell Line ◽  
Parental Line ◽  
Acyl Chains ◽  
Resistant Cells

A series of stable cell mutants of mouse fibroblasts were previously isolated (Roos, D. S. and R. L. Davidson, 1980, Somatic Cell Genet., 6:381-390) that exhibit varying degrees of resistance to the fusion-inducing effect of polyethylene glycol (PEG), but are morphologically similar to the parental cells from which they were derived. Biochemical analysis of these mutant cell lines has revealed differences in whole cell lipid composition which are directly correlated with their susceptibility to fusion. Fusion-resistant cells contain elevated levels of neutral lipids, particularly triglycerides and an unusual ether-linked lipid, O-alkyl, diacylglycerol. This ether lipid is increased approximately 35-fold over parental cells in the most highly PEG-resistant cell line. Fusion-resistant cells also contain more highly saturated fatty acyl chains (ratio of saturated to polyunsaturated fatty acids [S/P ratio] approximately 4:1) than the parental line (S/P ratio approximately 1:1). Cells which are intermediate in their resistance to PEG have ether lipid and fatty acid composition which is intermediate between the parental cells and the most fusion-resistant mutants. In a related communication (Roos, D. S. and P. W. Choppin, 1985, J. Cell. Biol., 100:1591-1598) evidence is presented that alteration of lipid content can predictably control the fusion response of these cells.

Fatty acid composition and freeze–thaw resistance in lactobacilli

2000 ◽  
Vol 67 (2) ◽  
pp. 241-247 ◽  
Author(s):  
ANDREA GÓMEZ ZAVAGLIA ◽  
EDGARDO A. DISALVO ◽  
GRACIELA L. DE ANTONI
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Unsaturated Fatty Acids ◽  
Neutral Lipids ◽  
Cellular Fatty Acid ◽  
Lactobacillus Delbrueckii ◽  
Freeze Thaw ◽  
Overlap Coefficient

The fatty acid composition and freeze–thaw resistance of eight strains of thermophilic lactobacilli were studied. Seven of these contained the same polar and neutral lipids, the five major components making up 90% of the cellular fatty acid pool being 14[ratio ]0, 16[ratio ]0, 16[ratio ]1, 18[ratio ]1 and C19 cyclopropane (cyc19[ratio ]0). Strain comparison by means of cluster analysis based on the fatty acid ratios using the overlap coefficient revealed two well defined clusters. One was formed by three strains of species Lactobacillus delbrueckii subsp. lactis and Lb. delbrueckii subsp. delbrueckii, the other included five strains of the species Lb. delbrueckii subsp. bulgaricus, Lb. acidophilus and Lb. helveticus. Resistance of strains with a high content of unsaturated fatty acids (66–70%) decreased with increasing cyc19[ratio ]0 concentrations. In contrast, in strains with a low concentration of unsaturated fatty acids (42–49%), increasing cyc19[ratio ]0 levels were associated with increased freeze–thaw resistance.

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 Diethylstilbestrol Modifies the Structure of Model Membranes and Is Localized Close to the First Carbons of the Fatty Acyl Chains

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 220
Author(s):  
Alessio Ausili ◽  
Inés Rodríguez-González ◽  
Alejandro Torrecillas ◽  
José A. Teruel ◽  
Juan C. Gómez-Fernández
Keyword(s):  
Membrane Surface ◽  
Water Layer ◽  
Fatty Acyl ◽  
31P Nmr Spectroscopy ◽  
Relaxation Rates ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Acyl Chains ◽  
Dynamics Simulations

The synthetic estrogen diethylstilbestrol (DES) is used to treat metastatic carcinomas and prostate cancer. We studied its interaction with membranes and its localization to understand its mechanism of action and side-effects. We used differential scanning calorimetry (DSC) showing that DES fluidized the membrane and has poor solubility in DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) in the fluid state. Using small-angle X-ray diffraction (SAXD), it was observed that DES increased the thickness of the water layer between phospholipid membranes, indicating effects on the membrane surface. DSC, X-ray diffraction, and 31P-NMR spectroscopy were used to study the effect of DES on the Lα-to-HII phase transition, and it was observed that negative curvature of the membrane is promoted by DES, and this effect may be significant to understand its action on membrane enzymes. Using the 1H-NOESY-NMR-MAS technique, cross-relaxation rates for different protons of DES with POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) protons were calculated, suggesting that the most likely location of DES in the membrane is with the main axis parallel to the surface and close to the first carbons of the fatty acyl chains of POPC. Molecular dynamics simulations were in close agreements with the experimental results regarding the location of DES in phospholipids bilayers.

scholarly journals Ferroptotic cell death triggered by conjugated linolenic acids is mediated by ACSL1

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alexander Beatty ◽  
Tanu Singh ◽  
Yulia Y. Tyurina ◽  
Vladimir A. Tyurin ◽  
Svetlana Samovich ◽  
...  
Keyword(s):  
Cell Death ◽  
Therapeutic Potential ◽  
Neutral Lipids ◽  
Cell Types ◽  
Lipid Hydroperoxides ◽  
Conjugated Linolenic Acids ◽  
Cellular Lipids ◽  
Transcriptional Changes ◽  
Acyl Chains ◽  
Tumor Growth And Metastasis

AbstractFerroptosis is associated with lipid hydroperoxides generated by the oxidation of polyunsaturated acyl chains. Lipid hydroperoxides are reduced by glutathione peroxidase 4 (GPX4) and GPX4 inhibitors induce ferroptosis. However, the therapeutic potential of triggering ferroptosis in cancer cells with polyunsaturated fatty acids is unknown. Here, we identify conjugated linoleates including α-eleostearic acid (αESA) as ferroptosis inducers. αESA does not alter GPX4 activity but is incorporated into cellular lipids and promotes lipid peroxidation and cell death in diverse cancer cell types. αESA-triggered death is mediated by acyl-CoA synthetase long-chain isoform 1, which promotes αESA incorporation into neutral lipids including triacylglycerols. Interfering with triacylglycerol biosynthesis suppresses ferroptosis triggered by αESA but not by GPX4 inhibition. Oral administration of tung oil, naturally rich in αESA, to mice limits tumor growth and metastasis with transcriptional changes consistent with ferroptosis. Overall, these findings illuminate a potential approach to ferroptosis, complementary to GPX4 inhibition.

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