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.

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 Alterations in Lipid Levels of Mitochondrial Membranes Induced by Amyloid-ß: A Protective Role of Melatonin

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Sergio A. Rosales-Corral ◽  
Gabriela Lopez-Armas ◽  
Jose Cruz-Ramos ◽  
Valery G. Melnikov ◽  
Dun-Xian Tan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Fatty Acids ◽  
Mitochondrial Dysfunction ◽  
Cytoplasmic Membrane ◽  
Membrane Lipids ◽  
Protective Role ◽  
Intracerebral Injection ◽  
Mitochondrial Membranes

Alzheimer pathogenesis involves mitochondrial dysfunction, which is closely related to amyloid-ß(Aß) generation, abnormal tau phosphorylation, oxidative stress, and apoptosis. Alterations in membranal components, including cholesterol and fatty acids, their characteristics, disposition, and distribution along the membranes, have been studied as evidence of cell membrane alterations in AD brain. The majority of these studies have been focused on the cytoplasmic membrane; meanwhile the mitochondrial membranes have been less explored. In this work, we studied lipids and mitochondrial membranesin vivo, following intracerebral injection of fibrillar amyloid-ß(Aß). The purpose was to determine how Aßmay be responsible for beginning of a vicious cycle where oxidative stress and alterations in cholesterol, lipids and fatty acids, feed back on each other to cause mitochondrial dysfunction. We observed changes in mitochondrial membrane lipids, and fatty acids, following intracerebral injection of fibrillar Aßin aged Wistar rats. Melatonin, a well-known antioxidant and neuroimmunomodulator indoleamine, reversed some of these alterations and protected mitochondrial membranes from obvious damage. Additionally, melatonin increased the levels of linolenic and n-3 eicosapentaenoic acid, in the same site where amyloidßwas injected, favoring an endogenous anti-inflammatory pathway.

scholarly journals Heat stress elicits remodeling in the anther lipidome of peanut

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zolian S. Zoong Lwe ◽  
Ruth Welti ◽  
Daniel Anco ◽  
Salman Naveed ◽  
Sachin Rustgi ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Heat Stress ◽  
Fatty Acid ◽  
Membrane Lipids ◽  
Fatty Acid Desaturase ◽  
Susceptible Genotype ◽  
Unsaturated Lipid ◽  
Lipid Species ◽  
Lipid Unsaturation ◽  
Fatty Acid Amount

AbstractUnderstanding the changes in peanut (Arachis hypogaea L.) anther lipidome under heat stress (HT) will aid in understanding the mechanisms of heat tolerance. We profiled the anther lipidome of seven genotypes exposed to ambient temperature (AT) or HT during flowering. Under AT and HT, the lipidome was dominated by phosphatidylcholine (PC), phosphatidylethanolamine (PE), and triacylglycerol (TAG) species (> 50% of total lipids). Of 89 lipid analytes specified by total acyl carbons:total carbon–carbon double bonds, 36:6, 36:5, and 34:3 PC and 34:3 PE (all contain 18:3 fatty acid and decreased under HT) were the most important lipids that differentiated HT from AT. Heat stress caused decreases in unsaturation indices of membrane lipids, primarily due to decreases in highly-unsaturated lipid species that contained 18:3 fatty acids. In parallel, the expression of Fatty Acid Desaturase 3-2 (FAD3-2; converts 18:2 fatty acids to 18:3) decreased under HT for the heat-tolerant genotype SPT 06-07 but not for the susceptible genotype Bailey. Our results suggested that decreasing lipid unsaturation levels by lowering 18:3 fatty-acid amount through reducing FAD3 expression is likely an acclimation mechanism to heat stress in peanut. Thus, genotypes that are more efficient in doing so will be relatively more tolerant to HT.

scholarly journals Lipidomics Provides New Insight into Pathogenesis and Therapeutic Targets of the Ischemia—Reperfusion Injury

2021 ◽  
Vol 22 (6) ◽  
pp. 2798
Author(s):  
Zoran Todorović ◽  
Siniša Đurašević ◽  
Maja Stojković ◽  
Ilijana Grigorov ◽  
Slađan Pavlović ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Time Course ◽  
Membrane Lipids ◽  
Lipid Analysis ◽  
Cell Damage ◽  
Ischemia Reperfusion ◽  
Enzyme Inactivation ◽  
Critical Event ◽  
Tissue Ischemia ◽  
Insight Into

Lipids play an essential role in both tissue protection and damage. Tissue ischemia creates anaerobic conditions in which enzyme inactivation occurs, and reperfusion can initiate oxidative stress that leads to harmful changes in membrane lipids, the formation of aldehydes, and chain damage until cell death. The critical event in such a series of harmful events in the cell is the unwanted accumulation of fatty acids that leads to lipotoxicity. Lipid analysis provides additional insight into the pathogenesis of ischemia/reperfusion (I/R) disorders and reveals new targets for drug action. The profile of changes in the composition of fatty acids in the cell, as well as the time course of these changes, indicate both the mechanism of damage and new therapeutic possibilities. A therapeutic approach to reperfusion lipotoxicity involves attenuation of fatty acids overload, i.e., their transport to adipose tissue and/or inhibition of the adverse effects of fatty acids on cell damage and death. The latter option involves using PPAR agonists and drugs that modulate the transport of fatty acids via carnitine into the interior of the mitochondria or the redirection of long-chain fatty acids to peroxisomes.

scholarly journals Dietary fat intake in healthy adolescents: inverse relationships between the estimated intake of saturated fatty acids and serum cholesterol

2001 ◽  
Vol 85 (3) ◽  
pp. 333-341 ◽  
Author(s):  
Gösta Samuelson ◽  
Lars-Erik Bratteby ◽  
Rawya Mohsen ◽  
Bengt Vessby
Keyword(s):  
Fatty Acids ◽  
Serum Cholesterol ◽  
Milk Fat ◽  
Saturated Fatty Acids ◽  
Saturated Fat ◽  
Dietary Fatty Acids ◽  
Cholesterol Esters ◽  
Fat Intake ◽  
A Chain ◽  
The One

The objective of the present study was to describe the intake of dietary fatty acids among healthy 15-year-old boys and girls and to relate the intake of specific fatty acids and the fatty acid composition of the serum cholesterol esters to serum lipid, apolipoprotein (Apo) and insulin concentrations respectively. Fifty-two girls and forty-two boys were randomly selected from the official population register. Unexpectedly, significant inverse associations were found between the dietary content of saturated fatty acids with a chain length of four to fifteen C atoms, mainly derived from milk fat, as well as the corresponding fatty acids in the serum cholesterol esters, on the one hand and the serum concentrations of cholesterol and ApoB on the other. The estimated dietary intake of 4:0–10:0, 12:0 and 14:0 respectively, were all significantly inversely related to the serum cholesterol (r-0.32,r-0.31,r-0.30, all P<0.05) and ApoB (r-0.42,r-0.42, andr-0.40, all P<0.05) concentrations in girls and 12:0 to the ApoB concentration (r-0.55, P<0.01) in boys. The proportions of 12:0 and 15:0 in the serum cholesterol esters were negatively correlated with the serum cholesterol concentrations in both girls (r-0.34,r-0.32, P<0.05) and boys (r-0.53, P<0.01;r-0.32, P<0.05) and with the ApoB concentrations among boys (r-0.61, P<0.01;r-0.43, P<0.05). It is conceivable that milk fat contains or is associated with some component in the diet, or some other characteristics of the food intake, which counterbalances the expected positive relationships between saturated fat intake and lipid levels.

scholarly journals Rapid Mobilization of Membrane Lipids in Wheat Leaf Sheaths During Incompatible Interactions with Hessian Fly

2012 ◽  
Vol 25 (7) ◽  
pp. 920-930 ◽  
Author(s):  
Lieceng Zhu ◽  
Xuming Liu ◽  
Haiyan Wang ◽  
Chitvan Khajuria ◽  
John C. Reese ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Membrane Lipids ◽  
Hessian Fly ◽  
Delayed Response ◽  
Lipid Species ◽  
Polymerase Chain ◽  
Wheat Lines ◽  
Defense Molecules ◽  
Compatible Interactions ◽  
Incompatible Interactions

Hessian fly (HF) is a biotrophic insect that interacts with wheat on a gene-for-gene basis. We profiled changes in membrane lipids in two isogenic wheat lines: a susceptible line and its backcrossed offspring containing the resistance gene H13. Our results revealed a 32 to 45% reduction in total concentrations of 129 lipid species in resistant plants during incompatible interactions within 24 h after HF attack. A smaller and delayed response was observed in susceptible plants during compatible interactions. Microarray and real-time polymerase chain reaction analyses of 168 lipid-metabolism-related transcripts revealed that the abundance of many of these transcripts increased rapidly in resistant plants after HF attack but did not change in susceptible plants. In association with the rapid mobilization of membrane lipids, the concentrations of some fatty acids and 12-oxo-phytodienoic acid (OPDA) increased specifically in resistant plants. Exogenous application of OPDA increased mortality of HF larvae significantly. Collectively, our data, along with previously published results, indicate that the lipids were mobilized through lipolysis, producing free fatty acids, which were likely further converted into oxylipins and other defense molecules. Our results suggest that rapid mobilization of membrane lipids constitutes an important step for wheat to defend against HF attack.

scholarly journals Bacterial precursors and unsaturated long-chain fatty acids are biomarkers of North-Atlantic demosponges

2020 ◽  
Author(s):  
Anna de Kluijver ◽  
Klaas G.J. Nierop ◽  
Teresa M. Morganti ◽  
Martijn C. Bart ◽  
Beate M. Slaby ◽  
...  
Keyword(s):  
Fatty Acids ◽  
North Atlantic ◽  
Deep Sea ◽  
North Atlantic Ocean ◽  
Carbon Isotopic Composition ◽  
Building Blocks ◽  
Functional Ecology ◽  
The North ◽  
A Chain ◽  
Long Chain

AbstractSponges produce distinct fatty acids (FAs) that (potentially) can be used as chemotaxonomic and ecological biomarkers to study endosymbiont-host interactions and the functional ecology of sponges. Here, we present FA profiles of five common habitat-building deep-sea sponges (class Demospongiae, order Tetractinellida), which are classified as high microbial abundance (HMA) species. Geodia hentscheli, G. parva, G. atlantica, G. barretti, and Stelletta rhaphidiophora were collected from boreal and Arctic sponge grounds in the North-Atlantic Ocean. Bacterial FAs dominated in all five species and particularly isomeric mixtures of mid-chain branched FAs (MBFAs, 8- and 9-Me-C16:0 and 10 and 11-Me-C18:0) were found in high abundance (together ≥ 20% of total FAs) aside more common bacterial markers. In addition, the sponges produced long-chain linear, mid- and a(i)-branched unsaturated FAs (LCFAs) with a chain length of 24‒28 C atoms and had predominantly the typical Δ5,9 unsaturation, although also Δ9,19 and (yet undescribed) Δ11,21 unsaturations were identified. G. parva and S. rhaphidiophora each produced distinct LCFAs, while G. atlantica, G. barretti, and G. hentscheli produced similar LCFAs, but in different ratios. The different bacterial precursors varied in carbon isotopic composition (δ13C), with MBFAs being more enriched compared to other bacterial (linear and a(i)-branched) FAs. We propose biosynthetic pathways for different LCFAs from their bacterial precursors, that are consistent with small isotopic differences found in LCFAs. Indeed, FA profiles of deep-sea sponges can serve as chemotaxonomic markers and support the conception that sponges acquire building blocks from their endosymbiotic bacteria.

Sign in / Sign up

Export Citation Format

Share Document