De la peroxydation lipidique radioinduite : les facteurs déterminant l'oxydabilité des lipides

2001 ◽  
Vol 79 (2) ◽  
pp. 144-153 ◽  
Author(s):  
Samy Rémita
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acids ◽  
Membrane Lipids ◽  
Membrane Damage ◽  
Chain Reaction ◽  
Amphiphilic Molecules ◽  
Essential Components ◽  
Radiation Induced ◽  
A Chain ◽  
Peroxydation Lipidique

Lipids are the essential components of cell membranes and lipoproteins. Their peroxidation plays an important role in numerous pathologies in which oxidative stress is involved. Lipid peroxidation occurs through a chain reaction that contributes to membrane damage in cells. It results in the conversion of fatty acids to polar hydroperoxides and leads to the breakdown or malfunction of the membrane. Lipids are amphiphilic molecules that aggregate in aqueous solutions into micelles and liposoms. The effect of this structural organization is significant in studies of radiation-induced peroxidation damage in highly ordered biological systems such as biological membranes. In this paper, a synthesis of the data concerning radioinduced lipid peroxidation is completed by an original review of the different parameters that determine lipid oxidizability. In addition, the influence of lipid aggregation and the effect of molecular packing are discussed.Key words: radiolysis, peroxidation, lipids, fatty acids.

scholarly journals The α6β4 integrin promotes resistance to ferroptosis

2017 ◽  
Vol 216 (12) ◽  
pp. 4287-4297 ◽  
Author(s):  
Caitlin W. Brown ◽  
John J. Amante ◽  
Hira Lal Goel ◽  
Arthur M. Mercurio
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acids ◽  
Extracellular Matrix ◽  
Cancer Biology ◽  
Membrane Lipids ◽  
Lipid Peroxides ◽  
Causal Link ◽  
Carcinoma Cells ◽  
Adherent Cells ◽  
Α6β4 Integrin

Increases in lipid peroxidation can cause ferroptosis, a form of cell death triggered by inhibition of glutathione peroxidase 4 (GPX4), which catalyzes the reduction of lipid peroxides and is a target of ferroptosis inducers, such as erastin. The α6β4 integrin protects adherent epithelial and carcinoma cells from ferroptosis induced by erastin. In addition, extracellular matrix (ECM) detachment is a physiologic trigger of ferroptosis, which is evaded by α6β4. The mechanism that enables α6β4 to evade ferroptosis involves its ability to protect changes in membrane lipids that are proferroptotic. Specifically, α6β4-mediated activation of Src and STAT3 suppresses expression of ACSL4, an enzyme that enriches membranes with long polyunsaturated fatty acids and is required for ferroptosis. Adherent cells lacking α6β4 require an inducer, such as erastin, to undergo ferroptosis because they sustain GPX4 expression, despite their increase in ACSL4. In contrast, ECM detachment of cells lacking α6β4 is sufficient to trigger ferroptosis because GPX4 is suppressed. This causal link between α6β4 and ferroptosis has implications for cancer biology and therapy.

scholarly journals Overexpression of OLE1 Enhances Cytoplasmic Membrane Stability and Confers Resistance to Cadmium in Saccharomyces cerevisiae

2016 ◽  
Vol 83 (1) ◽  
Author(s):  
Zhijia Fang ◽  
Zhongxiang Chen ◽  
Song Wang ◽  
Ping Shi ◽  
Yuhu Shen ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acids ◽  
Cytoplasmic Membrane ◽  
Unsaturated Fatty Acids ◽  
Membrane Damage ◽  
Cadmium Stress ◽  
Feedback Mechanism ◽  
Content Type ◽  
Positive Feedback Mechanism ◽  
Delta 9 Desaturase

ABSTRACT The heavy metal cadmium is widely used and released into the environment, posing a severe threat to crops and humans. Saccharomyces cerevisiae is one of the most commonly used organisms in the investigation of environmental metal toxicity. We investigated cadmium stress and the adaptive mechanisms of yeast by screening a genome-wide essential gene overexpression library. A candidate gene, OLE1, encodes a delta-9 desaturase and was associated with high anti-cadmium-stress activity. The results demonstrated that the expression of OLE1 was positively correlated with cadmium stress tolerance and induction was independent of Mga2p and Spt23p (important regulatory factors for OLE1). Moreover, in response to cadmium stress, cellular levels of monounsaturated fatty acids were increased. The addition of exogenous unsaturated fatty acids simulated overexpression of OLE1, leading to cadmium resistance. Such regulation of OLE1 in the synthesis of unsaturated fatty acids may serve as a positive feedback mechanism to help cells counter the lipid peroxidation and cytoplasmic membrane damage caused by cadmium. IMPORTANCE A S. cerevisiae gene encoding a delta-9 desaturase, OLE1, was associated with high anti-cadmium-stress activity. The data suggest that the regulation of OLE1 in the synthesis of unsaturated fatty acids may serve as a positive feedback mechanism to help yeast cells counter the lipid peroxidation and cytoplasmic membrane damage caused by cadmium. The discovery of OLE1 involvement in membrane stability may indicate a novel defense strategy against cadmium stress.

scholarly journals Revealing Further Insights on Chilling Injury of Postharvest Bananas by Untargeted Lipidomics

Foods ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 894 ◽  
Author(s):  
Juan Liu ◽  
Qingxin Li ◽  
Junjia Chen ◽  
Yueming Jiang
Keyword(s):  
Fatty Acids ◽  
Low Temperature ◽  
Unsaturated Fatty Acids ◽  
Membrane Lipids ◽  
Saturated Fatty Acids ◽  
Chilling Injury ◽  
Membrane Damage ◽  
Membrane Lipid ◽  
Banana Fruit ◽  
Control Fruit

Chilling injury is especially prominent in postharvest bananas stored at low temperature below 13 °C. To elucidate better the relationship between cell membrane lipids and chilling injury, an untargeted lipidomics approach using ultra-performance liquid chromatography–mass spectrometry was conducted. Banana fruit were stored at 6 °C for 0 (control) and 4 days and then sampled for lipid analysis. After 4 days of storage, banana peel exhibited a marked chilling injury symptom. Furthermore, 45 lipid compounds, including glycerophospholipids, saccharolipids, and glycerolipids, were identified with significant changes in peel tissues of bananas stored for 4 days compared with the control fruit. In addition, higher ratio of digalactosyldiacylglycerol (DGDG) to monogalactosyldiacylglycerol (MGDG) and higher levels of phosphatidic acid (PA) and saturated fatty acids but lower levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and unsaturated fatty acids were observed in banana fruit with chilling injury in contrast to the control fruit. Meanwhile, higher activities of phospholipase D (PLD) and lipoxygenase (LOX) were associated with significantly upregulated gene expressions of MaPLD1 and MaLOX2 and higher malondialdehyde (MDA) content in chilling injury-related bananas. In conclusion, our study indicated that membrane lipid degradation resulted from reduced PC and PE, but accumulated PA, while membrane lipid peroxidation resulted from the elevated saturation of fatty acids, resulting in membrane damage which subsequently accelerated the chilling injury occurrence of banana fruit during storage at low temperature.

scholarly journals A membrane-associated lipomannan in micrococci

1975 ◽  
Vol 151 (2) ◽  
pp. 387-397 ◽  
Author(s):  
D A Powell ◽  
M Duckworth ◽  
J Baddiley
Keyword(s):  
Fatty Acids ◽  
Succinic Acid ◽  
Cytoplasmic Membrane ◽  
Membrane Lipids ◽  
Branch Points ◽  
Glycerol Moiety ◽  
Micrococcus Lysodeikticus ◽  
Glycerol Ester ◽  
A Chain ◽  
Lipoteichoic Acids

Membranes of Micrococcus lysodeikticus, Micrococcus flavus and Micrococcus sodonensis contain acidic lipomannans. Lipoteichoic acids could not be detected in these organisms, and the suggestion that they are substituted for by the lipomannans is strengthened by the chemical and physical resemblances between the two polymers. The mannans contain glycerol, ester-linked fatty acids and mono-esterified succinic acid residues, giving them both hydrophobic and charged properties. The M. lysodeikticus mannan has a chain of about 60 hexose units with two branch points, and is joined at its reducing end to the 1-position of a glycerol moiety bearing two fatty acid residues. Succinic acid on the mannan enables it to bind Mg2+ efficiently, and the polymer is firmly associated with the cytoplasmic membrane, probably by intercalation of its fatty acids with those of the membrane lipids.

RADIATION-INDUCED CYCLOREVERSION OF INDENE CYCLOBUTANE DIMERS INn-BUTYL CHLORIDE BY A CHAIN REACTION MECHANISM

1979 ◽  
Vol 8 (9) ◽  
pp. 1149-1152
Author(s):  
Tetsuro Majima ◽  
Chyongjin Pac ◽  
Setsuo Takamuku ◽  
Hiroshi Sakurai
Keyword(s):  
Reaction Mechanism ◽  
Butyl Chloride ◽  
Chain Reaction ◽  
Cyclobutane Dimers ◽  
Radiation Induced ◽  
A Chain

Melatonin reduces high levels of lipid peroxidation induced by potassium iodate in porcine thyroid

2019 ◽  
pp. 1-7 ◽  
Author(s):  
Paulina Iwan ◽  
Jan Stepniak ◽  
Malgorzata Karbownik-Lewinska
Keyword(s):  
Lipid Peroxidation ◽  
Oxidative Damage ◽  
Membrane Lipids ◽  
Chemical Properties ◽  
Iodine Concentration ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Protective Effects ◽  
Potassium Iodate ◽  
Hormone Synthesis

Abstract. Iodine is essential for thyroid hormone synthesis. Under normal iodine supply, calculated physiological iodine concentration in the thyroid is approx. 9 mM. Either potassium iodide (KI) or potassium iodate (KIO3) are used in iodine prophylaxis. KI is confirmed as absolutely safe. KIO3 possesses chemical properties suggesting its potential toxicity. Melatonin (N-acetyl-5-methoxytryptamine) is an effective antioxidant and free radical scavenger. Study aims: to evaluate potential protective effects of melatonin against oxidative damage to membrane lipids (lipid peroxidation, LPO) induced by KI or KIO3 in porcine thyroid. Homogenates of twenty four (24) thyroids were incubated in presence of either KI or KIO3 without/with melatonin (5 mM). As melatonin was not effective against KI-induced LPO, in the next step only KIO3 was used. Homogenates were incubated in presence of KIO3 (200; 100; 50; 25; 20; 15; 10; 7.5; 5.0; 2.5; 1.25 mM) without/with melatonin or 17ß-estradiol. Five experiments were performed with different concentrations of melatonin (5.0; 2.5; 1.25; 1.0; 0.625 mM) and one with 17ß-estradiol (1.0 mM). Malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) concentration (LPO index) was measured spectrophotometrically. KIO3 increased LPO with the strongest damaging effect (MDA + 4-HDA level: ≈1.28 nmol/mg protein, p < 0.05) revealed at concentrations of around 15 mM, thus corresponding to physiological iodine concentrations in the thyroid. Melatonin reduced LPO (MDA + 4-HDA levels: from ≈0.97 to ≈0,76 and from ≈0,64 to ≈0,49 nmol/mg protein, p < 0.05) induced by KIO3 at concentrations of 10 mM or 7.5 mM. Conclusion: Melatonin can reduce very strong oxidative damage to membrane lipids caused by KIO3 used in doses resulting in physiological iodine concentrations in the thyroid.

Observations on a Relationship between Steroid Metabolism and the Concentration of Plasma Fibrinogen

1963 ◽  
Vol 10 (02) ◽  
pp. 400-405 ◽  
Author(s):  
B. A Amundson ◽  
L. O Pilgeram
Keyword(s):  
Blood Coagulation ◽  
Methyl Ether ◽  
Broad Spectrum ◽  
Human Subjects ◽  
Plasma Fibrinogen ◽  
Steroid Metabolism ◽  
Specific Site ◽  
Chain Reaction ◽  
Normal Human ◽  
A Chain

SummaryEnovid (5 mg norethynodrel and 0.075 mg ethynylestradiol-3-methyl ether) therapy in young normal human subjects causes an increase in plasma fibrinogen of 32.4% (P >C 0.001). Consideration of this effect together with other effects of Enovid on the activity of specific blood coagulatory factors suggests that the steroids are exerting their effect at a specific site of the blood coagulation and/or fibrinolytic system. The broad spectrum of changes which are induced by the steroids may be attributed to a combination of a chain reaction and feed-back control.

Lipid Profile of Pig Tissues Contrasting in Meat Production

2019 ◽  
Vol 09 ◽  
Author(s):  
Vitaly A. Bekenev ◽  
Anatoly A. Arishin ◽  
Sergei N. Mager ◽  
Izolda V. Bolshakova ◽  
Natalia L. Tretyakova ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acids ◽  
Linoleic Acid ◽  
Live Weight ◽  
Blood Lipid ◽  
Meat Production ◽  
Thoracic Vertebrae ◽  
Organoleptic Properties ◽  
Biochemical Characteristics

Background: Studies were carried out on two breeds of pigs - Pietrain (P), and Kemerovo (K), contrasting in composition of carcasses, and their hybrids. Objective: The purpose of this work was to establish the characteristics of the composition of lipids of intramuscular fat (IMF), back fat and serum, organoleptic qualities in animals of these breeds. Methods: Animals of 10 individuals in each group were fed on a standard feed and slaughtered with a live weight of 95-100 kg. The quality of carcasses, the biochemical characteristics of blood, the composition of fatty acids and cholesterol in meat and fat, and blood lipid peroxidation were determined. Results: Thickness on the back fat (BF) at the level of 6-7 thoracic vertebrae with a live weight of 100 kg was 35.8 ± 1.65 mm in pigs of breed K, in hybrids - 27.6 ± 1.06, and in breed P - 19, 6 ± 1.43 mm. IMF in pigs of breed K was almost 4.5 times greater than that of breed P. IMF K breed contained 2 times less cholesterol than in P (2.34 vs. 4.68%). In the IMF, K was 2 times less polyunsaturated fatty acids (PUFA), than P, 7.82 and 15.22%, linoleic acid, 6.74% and 12.42% respectively (p &lt;0.005).The organoleptic properties of meat and salted back fat were significantly higher in breed K (P = 0.05). Conclusion: The data obtained allow us to establish priorities in the use of products of specific breeds of pigs, depending on medical requirements.

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