Статті в журналах: "Lipid degradation"

1

Appel, Thomas Raul, Michael Wolff, Friedrich von Rheinbaben, Michael Heinzel, and Detlev Riesner. "Heat stability of prion rods and recombinant prion protein in water, lipid and lipid–water mixtures." Journal of General Virology 82, no. 2 (February 1, 2001): 465–73. http://dx.doi.org/10.1099/0022-1317-82-2-465.

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Prion rods, i.e. insoluble infectious aggregates of the N-terminally truncated form of the prion protein, PrP 27–30, and the corresponding recombinant protein, rPrP(90–231), were autoclaved in water, bovine lipid or lipid–water mixtures for 20 min at temperatures from 100 to 170 °C. A protocol was developed for the quantitative precipitation of small amounts of protein from large excesses of lipid. PrP remaining undegraded after autoclaving was quantified by Western blot and degradation factors were calculated. The Arrhenius plot of the rate of degradation vs temperature yielded linear relationships for prion rods in water or lipid–water as well as for rPrP(90–231) in lipid–water. The presence of lipids increased the heat stability of prion rods, especially at lower temperatures. Prion rods had a much higher thermal stability compared to rPrP. Autoclaving of prion rods in pure lipid gave different results – not simple degradation but bands indicative of covalently linked dimers, tetramers and higher aggregates. The heat stability of prion rods in pure lipid exceeded that in lipid–water mixtures. Degradation factors larger than 104 were reached at 170 °C in the presence of lipids and at 150 °C in the absence of lipids. The linear correlation of the data allows cautious extrapolation to conditions not tested, i.e. temperatures higher than 170 °C. A factual basis for assessing the biological safety of industrial processes utilizing potentially BSE-or scrapie-contaminated animal fat is provided.

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2

Shahidi, Fereidoon, and Abul Hossain. "Role of Lipids in Food Flavor Generation." Molecules 27, no. 15 (August 6, 2022): 5014. http://dx.doi.org/10.3390/molecules27155014.

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Lipids in food are a source of essential fatty acids and also play a crucial role in flavor and off-flavor development. Lipids contribute to food flavor generation due to their degradation to volatile compounds during food processing, heating/cooking, and storage and/or interactions with other constituents developed from the Maillard reaction and Strecker degradation, among others. The degradation of lipids mainly occurs via autoxidation, photooxidation, and enzymatic oxidation, which produce a myriad of volatile compounds. The oxidation of unsaturated fatty acids generates hydroperoxides that then further break down to odor-active volatile secondary lipid oxidation products including aldehydes, alcohols, and ketones. In this contribution, a summary of the most relevant and recent findings on the production of volatile compounds from lipid degradation and Maillard reactions and their interaction has been compiled and discussed. In particular, the effects of processing such as cooking, drying, and fermentation as well as the storage of lipid-based foods on flavor generation are briefly discussed.

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3

Masclaux-Daubresse, Céline, Sabine d’Andrea, Isabelle Bouchez, and Jean-Luc Cacas. "Reserve lipids and plant autophagy." Journal of Experimental Botany 71, no. 10 (February 21, 2020): 2854–61. http://dx.doi.org/10.1093/jxb/eraa082.

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Abstract Autophagy is a universal mechanism that facilitates the degradation of unwanted cytoplasmic components in eukaryotic cells. In this review, we highlight recent developments in the investigation of the role of autophagy in lipid homeostasis in plants by comparison with algae, yeast, and animals. We consider the storage compartments that form the sources of lipids in plants, and the roles that autophagy plays in the synthesis of triacylglycerols and in the formation and maintenance of lipid droplets. We also consider the relationship between lipids and the biogenesis of autophagosomes, and the role of autophagy in the degradation of lipids in plants.

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4

Alvebratt, Caroline, Tahnee J. Dening, Michelle Åhlén, Ocean Cheung, Maria Strømme, Adolf Gogoll, Clive A. Prestidge, and Christel A. S. Bergström. "In Vitro Performance and Chemical Stability of Lipid-Based Formulations Encapsulated in a Mesoporous Magnesium Carbonate Carrier." Pharmaceutics 12, no. 5 (May 6, 2020): 426. http://dx.doi.org/10.3390/pharmaceutics12050426.

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Lipid-based formulations can circumvent the low aqueous solubility of problematic drug compounds and increase their oral absorption. As these formulations are often physically unstable and costly to manufacture, solidification has been suggested as a way to minimize these issues. This study evaluated the physicochemical stability and in vitro performance of lipid-loaded mesoporous magnesium carbonate (MMC) particles with an average pore size of 20 nm. A medium chain lipid was loaded onto the MMC carrier via physical adsorption. A modified in vitro lipolysis setup was then used to study lipid release and digestion with 1H nuclear magnetic resonance spectroscopy. The lipid loading efficiency with different solidification techniques was also evaluated. The MMC, unlike more commonly used porous silicate carriers, dissolved during the lipolysis assay, providing a rapid release of encapsulated lipids into solution. The digestion of the dispersed lipid-loaded MMC therefore resembled that of a coarse dispersion of the lipid. The stability data demonstrated minor degradation of the lipid within the pores of the MMC particles, but storage for three months did not reveal extensive degradation. To conclude, lipids can be adsorbed onto MMC, creating a solid powder from which the lipid is readily released into the solution during in vitro digestion. The chemical stability of the formulation does however merit further attention.

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5

Huang, Leng-Jie, and Rey-Huei Chen. "Lipid saturation induces degradation of squalene epoxidase for sterol homeostasis and cell survival." Life Science Alliance 6, no. 1 (November 11, 2022): e202201612. http://dx.doi.org/10.26508/lsa.202201612.

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A fluid membrane containing a mix of unsaturated and saturated lipids is essential for life. However, it is unclear how lipid saturation might affect lipid homeostasis, membrane-associated proteins, and membrane organelles. Here, we generate temperature-sensitive mutants of the sole fatty acid desaturase geneOLE1in the budding yeastSaccharomyces cerevisiae. Using these mutants, we show that lipid saturation triggers the endoplasmic reticulum–associated degradation (ERAD) of squalene epoxidase Erg1, a rate-limiting enzyme in sterol biosynthesis, via the E3 ligase Doa10-Ubc7 complex. We identify the P469L mutation that abolishes the lipid saturation–induced ERAD of Erg1. Overexpressed WT or stable Erg1 mutants all mislocalize into foci in theole1mutant, whereas the stable Erg1 causes aberrant ER and severely compromises the growth ofole1, which are recapitulated bydoa10deletion. The toxicity of the stable Erg1 anddoa10deletion is due to the accumulation of lanosterol and misfolded proteins inole1. Our study identifies Erg1 as a novel lipid saturation–regulated ERAD target, manifesting a close link between lipid homeostasis and proteostasis that maintains sterol homeostasis under the lipid saturation condition for cell survival.

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6

Settembre, Carmine, and Andrea Ballabio. "Lysosome: regulator of lipid degradation pathways." Trends in Cell Biology 24, no. 12 (December 2014): 743–50. http://dx.doi.org/10.1016/j.tcb.2014.06.006.

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7

Suzuki, Kunio. "Lipid Peroxide Degradation by Intestinal Bacteria." Microbial Ecology in Health and Disease 6, no. 3 (January 1993): 133–36. http://dx.doi.org/10.3109/08910609309141318.

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8

Barrow, RA, and RJ Capon. "Epoxy Lipids From the Australian Epiphytic Brown Alga Notheia anomala." Australian Journal of Chemistry 43, no. 5 (1990): 895. http://dx.doi.org/10.1071/ch9900895.

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A detailed reinvestigation of the chemistry of Notheia anomala has resulted in the isolation of the known C19 lipid (1) together with 13 new C19 lipids (2), (3), (3a,b,c) (4), (4a,b,c) (8), (10),(13) and (14), one new C21 lipid (15) and two known C21 lipids, (17) and (18), and a new C17 lipid (19). The structures of these metabolites were established by spectroscopic analysis together with chemical derivatization and degradation. Absolute stereochemistries were determined by chemical and biosynthetic correlation to (1). A common biosynthetic pathway is proposed for all the oxygenated lipids from N. Anomala.

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9

Ekiel, Irena, and G. Dennis Sprott. "Identification of degradation artifacts formed upon treatment of hydroxydiether lipids from methanogens with methanolic HCl." Canadian Journal of Microbiology 38, no. 8 (August 1, 1992): 764–68. http://dx.doi.org/10.1139/m92-124.

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Treatment of purified 3-hydroxydiether lipid from Methanosarcina barkeri by standard conditions for head-group removal (2.5% methanolic HCl, 70 °C) resulted in conversion to six identifiable degradation products. The four most abundant products were identified by mass spectrometry and nuclear magnetic resonance as monophytanylglycerol, 3-methoxydiether, and cis–trans isomers of a diether unsaturated between carbons 3 and 4. The latter lipid products may be mistaken for 2,3-di-O-phytanyl-sn-glycerol (standard diether) and 2-O-sesterterpanyl-3-O-phytanyl-sn-glycerol when separated by thin-layer chromatography. Key words: hydroxydiether lipids, degradation artifacts, methanolic HCl, Methanosarcina barkeri.

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10

Busija, Anna R., Hemal H. Patel, and Paul A. Insel. "Caveolins and cavins in the trafficking, maturation, and degradation of caveolae: implications for cell physiology." American Journal of Physiology-Cell Physiology 312, no. 4 (April 1, 2017): C459—C477. http://dx.doi.org/10.1152/ajpcell.00355.2016.

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Caveolins (Cavs) are ~20 kDa scaffolding proteins that assemble as oligomeric complexes in lipid raft domains to form caveolae, flask-shaped plasma membrane (PM) invaginations. Caveolae (“little caves”) require lipid-lipid, protein-lipid, and protein-protein interactions that can modulate the localization, conformational stability, ligand affinity, effector specificity, and other functions of proteins that are partners of Cavs. Cavs are assembled into small oligomers in the endoplasmic reticulum (ER), transported to the Golgi for assembly with cholesterol and other oligomers, and then exported to the PM as an intact coat complex. At the PM, cavins, ~50 kDa adapter proteins, oligomerize into an outer coat complex that remodels the membrane into caveolae. The structure of caveolae protects their contents (i.e., lipids and proteins) from degradation. Cellular changes, including signal transduction effects, can destabilize caveolae and produce cavin dissociation, restructuring of Cav oligomers, ubiquitination, internalization, and degradation. In this review, we provide a perspective of the life cycle (biogenesis, degradation), composition, and physiologic roles of Cavs and caveolae and identify unanswered questions regarding the roles of Cavs and cavins in caveolae and in regulating cell physiology.1

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11

Sandhoff, Konrad. "Metabolic and cellular bases of sphingolipidoses." Biochemical Society Transactions 41, no. 6 (November 20, 2013): 1562–68. http://dx.doi.org/10.1042/bst20130083.

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Lysosomes are cellular stomachs. They degrade macromolecules and release their components as nutrients into the cytosol. Digestion of sphingolipids and other membrane lipids occurs at luminal intraendosomal vesicles and IMs (intraendosomal membranes). Sphingolipid and membrane digestion needs catabolic hydrolases with the help of lipid-binding proteins [SAPs (sphingolipid activator proteins)] and anionic lipids such as BMP [bis(monoacylglycero)phosphate]. Inherited defects of hydrolases or SAPs or uptake of cationic amphiphilic drugs cause lipid accumulation, eventually leading to death, especially in inherited sphingolipid storage diseases. IMs are formed during endocytosis and their lipid composition is adjusted for degradation. Their cholesterol content, which stabilizes membranes, decreases and the level of negatively charged BMP, which stimulates sphingolipid degradation, increases. At the level of late endosomes, cholesterol is transported out of the luminal vesicles preferentially by cholesterol-binding proteins, NPC (Niemann–Pick type C)-2 and NPC-1. Their defects lead to an endolysosomal accumulation of cholesterol and sphingolipids in Niemann–Pick type C disease. BMP and ceramide stimulate NPC-2-mediated cholesterol transfer, whereas sphingomyelin inhibits it. Anionic membrane lipids also activate sphingomyelin degradation by ASM (acid sphingomyelinase), facilitating cholesterol export by NPC-2. ASM is a non-specific phospholipase C and degrades more than 23 phospholipids. SAPs are membrane-perturbing proteins which solubilize lipids, facilitating glycolipid digestion by presenting them to soluble catabolic enzymes at acidic pH. High BMP and low cholesterol levels favour lipid extraction and membrane disintegration by saposin A and B. The simultaneous inherited defect of saposins A–D causes a severe membrane and sphingolipid storage disease, also disrupting the water permeability barrier of the skin.

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12

Hölzl, Georg, and Peter Dörmann. "Chloroplast Lipids and Their Biosynthesis." Annual Review of Plant Biology 70, no. 1 (April 29, 2019): 51–81. http://dx.doi.org/10.1146/annurev-arplant-050718-100202.

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Chloroplasts contain high amounts of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) and low levels of the anionic lipids sulfoquinovosyldiacylglycerol (SQDG), phosphatidylglycerol (PG), and glucuronosyldiacylglycerol (GlcADG). The mostly extraplastidial lipid phosphatidylcholine is found only in the outer envelope. Chloroplasts are the major site for fatty acid synthesis. In Arabidopsis, a certain proportion of glycerolipids is entirely synthesized in the chloroplast (prokaryotic lipids). Fatty acids are also exported to the endoplasmic reticulum and incorporated into lipids that are redistributed to the chloroplast (eukaryotic lipids). MGDG, DGDG, SQDG, and PG establish the thylakoid membranes and are integral constituents of the photosynthetic complexes. Phosphate deprivation induces phospholipid degradation accompanied by the increase in DGDG, SQDG, and GlcADG. During freezing and drought stress, envelope membranes are stabilized by the conversion of MGDG into oligogalactolipids. Senescence and chlorotic stress lead to lipid and chlorophyll degradation and the deposition of acyl and phytyl moieties as fatty acid phytyl esters.

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13

Lum, P. Y., and R. Wright. "Degradation of HMG-CoA reductase-induced membranes in the fission yeast, Schizosaccharomyces pombe." Journal of Cell Biology 131, no. 1 (October 1, 1995): 81–94. http://dx.doi.org/10.1083/jcb.131.1.81.

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Elevated levels of certain membrane proteins, including the sterol biosynthetic enzyme HMG-CoA reductase, induce proliferation of the endoplasmic reticulum. When the amounts of these proteins return to basal levels, the proliferated membranes are degraded, but the molecular details of this degradation remain unknown. We have examined the degradation of HMG-CoA reductase-induced membranes in the fission yeast, Schizosaccharomyces pombe. In this yeast, increased levels of the Saccharomyces cerevisiae HMG-CoA reductase isozyme encoded by HMG1 induced several types of membranes, including karmellae, which formed a cap of stacked membranes that partially surrounded the nucleus. When expression of HMG1 was repressed, the karmellae detached from the nucleus and formed concentric, multilayered membrane whorls that were then degraded. During the degradation process, CDCFDA-stained compartments distinct from preexisting vacuoles formed within the interior of the whorls. In addition to these compartments, particles that contained neutral lipids also formed within the whorl. As the thickness of the whorl decreased, the lipid particle became larger. When degradation was complete, only the lipid particle remained. Cycloheximide treatment did not prevent the formation of whorls. Thus, new protein synthesis was not needed for the initial stages of karmellae degradation. On the contrary, cycloheximide promoted the detachment of karmellae to form whorls, suggesting that a short lived protein may be involved in maintaining karmellae integrity. Taken together, these results demonstrate that karmellae membranes differentiated into self-degradative organelles. This process may be a common pathway by which ER membranes are turned over in cells.

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14

Cisa-Wieczorek, Sabina, and María Isabel Hernández-Alvarez. "Deregulation of Lipid Homeostasis: A Fa(c)t in the Development of Metabolic Diseases." Cells 9, no. 12 (December 4, 2020): 2605. http://dx.doi.org/10.3390/cells9122605.

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Lipids are important molecules for human health. The quantity and quality of fats consumed in the diet have important effects on the modulation of both the natural biosynthesis and degradation of lipids. There is an important number of lipid-failed associated metabolic diseases and an increasing number of studies suggesting that certain types of lipids might be beneficial to the treatment of many metabolic diseases. The aim of the present work is to expose an overview of de novo biosynthesis, storage, and degradation of lipids in mammalian cells, as well as, to review the published data describing the beneficial effects of these processes and the potential of some dietary lipids to improve metabolic diseases.

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15

Komatsu, Toshiya, Keisuke Hanaki, and Tomonori Matsuo. "Prevention of Lipid Inhibition in Anaerobic Processes by Introducing a Two-Phase System." Water Science and Technology 23, no. 7-9 (April 1, 1991): 1189–200. http://dx.doi.org/10.2166/wst.1991.0570.

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The inhibitory effect of lipids and prevention of this inhibition in a two-phase anaerobic process were examined using laboratory-scale reactors and batch experiments. Lipids were satisfactorily degraded in a two-phase anaerobic filter while in a single-phase system, inhibition resulted in poor lipid degradation. Unsaturated long-chain fatty acids (LFAs) had a greater inhibitory effect than saturated LFAs. Methane production as well as beta-oxidation (degradation of saturated LFAs) were inhibited by unsaturated LFAs. The saturation of unsaturated LFAs was not inhibited, and palmitate (C16:0) was accumulated in the degradation of oleate (C18:l) or linoleate (C18:2). Greater inhibition was observed at low pH values. Continuous operation of a suspended-growth acidogenic reactor showed that hydraulic retention times (HRTs) of no less than 8 hours were necessary to mitigate the inhibition in a two-phase process. The fact that saturation of oleate occurred at HRTs no less than 8 hours suggests that the saturation of unsaturated LFAs in an acidogenic reactor is essential in the prevention of lipid inhibition in two-phase anaerobic processes.

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16

Domínguez, Rubén, Mirian Pateiro, Mohammed Gagaoua, Francisco J. Barba, Wangang Zhang, and José M. Lorenzo. "A Comprehensive Review on Lipid Oxidation in Meat and Meat Products." Antioxidants 8, no. 10 (September 25, 2019): 429. http://dx.doi.org/10.3390/antiox8100429.

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Meat and meat products are a fundamental part of the human diet. The protein and vitamin content, as well as essential fatty acids, gives them an appropriate composition to complete the nutritional requirements. However, meat constituents are susceptible to degradation processes. Among them, the most important, after microbial deterioration, are oxidative processes, which affect lipids, pigments, proteins and vitamins. During these reactions a sensory degradation of the product occurs, causing consumer rejection. In addition, there is a nutritional loss that leads to the formation of toxic substances, so the control of oxidative processes is of vital importance for the meat industry. Nonetheless, despite lipid oxidation being widely investigated for decades, the complex reactions involved in the process, as well as the different pathways and factors that influenced them, make that lipid oxidation mechanisms have not yet been completely understood. Thus, this article reviews the fundamental mechanisms of lipid oxidation, the most important oxidative reactions, the main factors that influence lipid oxidation, and the routine methods to measure compounds derived from lipid oxidation in meat.

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17

Kim, Ijung, Sang-Hyoun Kim, Hang-Sik Shin, and Jin-Young Jung. "Anaerobic lipid degradation through acidification and methanization." Journal of Microbiology and Biotechnology 20, no. 1 (January 28, 2010): 179–86. http://dx.doi.org/10.4014/jmb.0903.03020.

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18

Itkonen, Harri M., Michael Brown, Alfonso Urbanucci, Gregory Tredwell, Chung Ho Lau, Stefan Barfeld, Claire Hart, et al. "Lipid degradation promotes prostate cancer cell survival." Oncotarget 8, no. 24 (March 11, 2017): 38264–75. http://dx.doi.org/10.18632/oncotarget.16123.

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19

Stevenson, Julian, Edmond Y. Huang, and James A. Olzmann. "Endoplasmic Reticulum–Associated Degradation and Lipid Homeostasis." Annual Review of Nutrition 36, no. 1 (July 17, 2016): 511–42. http://dx.doi.org/10.1146/annurev-nutr-071715-051030.

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20

Zamora, Rosario, José L. Navarro, Isabel Aguilar, and Francisco J. Hidalgo. "Lipid-derived aldehyde degradation under thermal conditions." Food Chemistry 174 (May 2015): 89–96. http://dx.doi.org/10.1016/j.foodchem.2014.11.034.

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21

Keller, Markus A., Katrin Watschinger, Georg Golderer, Gabriele Werner-Felmayer, and Ernst R. Werner. "Fatty aldehyde dehydrogenase, the enzyme downstream of tetrahydrobiopterin-dependent alkylglycerol monooxygenase." Pteridines 24, no. 1 (June 1, 2013): 105–9. http://dx.doi.org/10.1515/pterid-2013-0004.

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AbstractThe tetrahydrobiopterin-dependent degradation of ether lipids by alkylglycerol monooxygenase (AGMO) produces fatty aldehydes, which are toxic to cells. Therefore, it is of great physiological importance that these harmful compounds are converted into their corresponding, less toxic fatty acids by fatty aldehyde dehydrogenase (FALDH). Dysfunction of this enzyme causes Sjögren-Larsson syndrome. This severe inherited disorder is accompanied by symptoms such as ichthyosis, mental retardation and spasticity. Surprisingly, fatty alcohols and not fatty aldehydes were found to accumulate in fibroblasts of Sjögren-Larsson syndrome patients, suggesting that there can be wide-ranging alterations in the lipid composition of patient cells. In particular, this has to be considered when searching for possible treatment options for patients suffering from Sjögren-Larsson syndrome. For example, inhibition of fatty aldehyde producing ether lipid degradation would have multiple implications on ether lipid- and fatty alcohol-mediated signalling pathways.

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22

Anheuser, Susi, Bernadette Breiden, and Konrad Sandhoff. "Membrane lipids and their degradation compounds control GM2 catabolism at intralysosomal luminal vesicles." Journal of Lipid Research 60, no. 6 (April 15, 2019): 1099–111. http://dx.doi.org/10.1194/jlr.m092551.

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The catabolism of ganglioside GM2 is dependent on three gene products. Mutations in any of these genes result in a different type of GM2 gangliosidosis (Tay-Sachs disease, Sandhoff disease, and the B1 and AB variants of GM2 gangliosidosis), with GM2 as the major lysosomal storage compound. GM2 is also a secondary storage compound in lysosomal storage diseases such as Niemann-Pick disease types A–C, with primary storage of SM in type A and cholesterol in types B and C, respectively. The reconstitution of GM2 catabolism at liposomal surfaces carrying GM2 revealed that incorporating lipids into the GM2-carrying membrane such as cholesterol, SM, sphingosine, and sphinganine inhibits GM2 hydrolysis by β-hexosaminidase A assisted by GM2 activator protein, while anionic lipids, ceramide, fatty acids, lysophosphatidylcholine, and diacylglycerol stimulate GM2 catabolism. In contrast, the hydrolysis of the synthetic, water-soluble substrate 4-methylumbelliferyl-6-sulfo-2-acetamido-2-deoxy-β-d-glucopyranoside was neither significantly affected by membrane lipids such as ceramide or SM nor stimulated by anionic lipids such as bis(monoacylglycero)phosphate added as liposomes, detergent micelles, or lipid aggregates. Moreover, hydrolysis-inhibiting lipids also had an inhibiting effect on the solubilization and mobilization of membrane-bound lipids by the GM2 activator protein, while the stimulating lipids enhanced lipid mobilization.—

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Severino, Patrícia, Tatiana Andreani, Ana Sofia Macedo, Joana F. Fangueiro, Maria Helena A. Santana, Amélia M. Silva, and Eliana B. Souto. "Current State-of-Art and New Trends on Lipid Nanoparticles (SLN and NLC) for Oral Drug Delivery." Journal of Drug Delivery 2012 (November 24, 2012): 1–10. http://dx.doi.org/10.1155/2012/750891.

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Lipids and lipid nanoparticles are extensively employed as oral-delivery systems for drugs and other active ingredients. These have been exploited for many features in the field of pharmaceutical technology. Lipids usually enhance drug absorption in the gastrointestinal tract (GIT), and when formulated as nanoparticles, these molecules improve mucosal adhesion due to small particle size and increasing their GIT residence time. In addition, lipid nanoparticles may also protect the loaded drugs from chemical and enzymatic degradation and gradually release drug molecules from the lipid matrix into blood, resulting in improved therapeutic profiles compared to free drug. Therefore, due to their physiological and biodegradable properties, lipid molecules may decrease adverse side effects and chronic toxicity of the drug-delivery systems when compared to other of polymeric nature. This paper highlights the importance of lipid nanoparticles to modify the release profile and the pharmacokinetic parameters of drugs when administrated through oral route.

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24

Rabel, Martin, Paul Warncke, Maria Thürmer, Cordula Grüttner, Christian Bergemann, Heinz-Dieter Kurland, Frank A. Müller, Andreas Koeberle, and Dagmar Fischer. "The differences of the impact of a lipid and protein corona on the colloidal stability, toxicity, and degradation behavior of iron oxide nanoparticles." Nanoscale 13, no. 20 (2021): 9415–35. http://dx.doi.org/10.1039/d0nr09053k.

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It was shown that proteins and lipids adsorb to the surface of IONP improving their colloidal stability and biocompatibility profile in vitro and in vivo. The degradation rate was reduced and correlated with the lipid but not the protein adsorption.

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25

Akita, Kae, Tomoko Takagi, Keiko Kobayashi, Kazuyuki Kuchitsu, Tsuneyoshi Kuroiwa, and Noriko Nagata. "Ultrastructural characterization of microlipophagy induced by the interaction of vacuoles and lipid bodies around generative and sperm cells in Arabidopsis pollen." Protoplasma 258, no. 1 (September 23, 2020): 129–38. http://dx.doi.org/10.1007/s00709-020-01557-2.

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AbstractDuring pollen maturation, various organelles change their distribution and function during development as male gametophytes. We analyzed the behavior of lipid bodies and vacuoles involved in lipophagy in Arabidopsis pollen using serial section SEM and conventional TEM. At the bicellular pollen stage, lipid bodies in the vegetative cells lined up at the surface of the generative cell. Vacuoles then tightly attached, drew in, and degraded the lipid bodies and eventually occupied the space of the lipid bodies. Degradation of lipid began before transfer of the entire contents of the lipid body. At the tricellular stage, vacuoles instead of lipid bodies surrounded the sperm cells. The degradation of lipid bodies is morphologically considered microautophagy. The atg2-1 Arabidopsis mutant is deficient in one autophagy-related gene (ATG). In this mutant, the assembly of vacuoles around sperm cells was sparser than that in wild-type pollen. The deficiency of ATG2 likely prevents or slows lipid degradation, although it does not prevent contact between organelles. These results demonstrate the involvement of microlipophagy in the pollen development of Arabidopsis.

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26

Wang, Bei, Yue Zhu, Congci Yu, Chongyang Zhang, Qing Tang, He Huang, and Zhendong Zhao. "Hepatitis C virus induces oxidation and degradation of apolipoprotein B to enhance lipid accumulation and promote viral production." PLOS Pathogens 17, no. 9 (September 7, 2021): e1009889. http://dx.doi.org/10.1371/journal.ppat.1009889.

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Hepatitis C virus (HCV) infection induces the degradation and decreases the secretion of apolipoprotein B (ApoB). Impaired production and secretion of ApoB-containing lipoprotein is associated with an increase in hepatic steatosis. Therefore, HCV infection-induced degradation of ApoB may contribute to hepatic steatosis and decreased lipoprotein secretion, but the mechanism of HCV infection-induced ApoB degradation has not been completely elucidated. In this study, we found that the ApoB level in HCV-infected cells was regulated by proteasome-associated degradation but not autophagic degradation. ApoB was degraded by the 20S proteasome in a ubiquitin-independent manner. HCV induced the oxidation of ApoB via oxidative stress, and oxidized ApoB was recognized by the PSMA5 and PSMA6 subunits of the 20S proteasome for degradation. Further study showed that ApoB was degraded at endoplasmic reticulum (ER)-associated lipid droplets (LDs) and that the retrotranslocation and degradation of ApoB required Derlin-1 but not gp78 or p97. Moreover, we found that knockdown of ApoB before infection increased the cellular lipid content and enhanced HCV assembly. Overexpression of ApoB-50 inhibited lipid accumulation and repressed viral assembly in HCV-infected cells. Our study reveals a novel mechanism of ApoB degradation and lipid accumulation during HCV infection and might suggest new therapeutic strategies for hepatic steatosis.

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Wang, Meng, Qiang Zhu, Xiaoxu Li, Jinhong Hu, Fan Song, Wangli Liang, Xiaorong Ma, Lingxia Wang, and Wenyu Liang. "Effect of Drought Stress on Degradation and Remodeling of Membrane Lipids in Nostoc flagelliforme." Foods 11, no. 12 (June 18, 2022): 1798. http://dx.doi.org/10.3390/foods11121798.

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Nostoc flagelliforme is a kind of terrestrial edible cyanobacteria with important ecological and economic value which has developed special mechanisms to adapt to drought conditions. However, the specific mechanism of lipidome changes in drought tolerance of N. flagelliforme has not been well understood. In this study, the ultra-high-performance liquid chromatography and mass spectrometry were employed to analyze the lipidome changes of N. flagelliforme under dehydration. A total of 853 lipid molecules were identified, of which 171 were significantly different from that of the control group. The digalactosyldiacylglycerol/monogalactosyldiacylglycerol (DGDG/MGDG) ratio was increased. The amount of wax ester (WE) was sharply decreased during drought stress, while Co (Q10) was accumulated. The levels of odd chain fatty acids (OCFAs) were increased under dehydration, positively responding to drought stress according to the energy metabolism state. In conclusion, the lipidomic data corroborated that oxidation, degradation, and biosynthesis of membrane lipids took place during lipid metabolism, which can respond to drought stress through the transformation of energy and substances. Besides, we constructed a lipid metabolic model demonstrating the regulatory mechanism of drought stress in N. flagelliforme. The present study provides insight into the defense strategies of cyanobacteria in lipid metabolic pathways.

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Shamin, Maria, Samantha J. Spratley, Stephen C. Graham, and Janet E. Deane. "A Tetrameric Assembly of Saposin A: Increasing Structural Diversity in Lipid Transfer Proteins." Contact 4 (January 2021): 251525642110523. http://dx.doi.org/10.1177/25152564211052382.

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Saposins are lipid transfer proteins required for the degradation of sphingolipids in the lysosome. These small proteins bind lipids by transitioning from a closed, monomeric state to an open conformation exposing a hydrophobic surface that binds and shields hydrophobic lipid tails from the aqueous environment. Saposins form a range of multimeric assemblies to encompass these bound lipids and present them to hydrolases in the lysosome. This lipid-binding property of human saposin A has been exploited to form lipoprotein nanodiscs suitable for structural studies of membrane proteins. Here we present the crystal structure of a unique tetrameric assembly of murine saposin A produced serendipitously, following modifications of published protocols for making lipoprotein nanodiscs. The structure of this new saposin oligomer highlights the diversity of tertiary arrangement that can be adopted by these important lipid transfer proteins.

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29

Meex, Ruth C. R., Patrick Schrauwen, and Matthijs K. C. Hesselink. "Modulation of myocellular fat stores: lipid droplet dynamics in health and disease." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 297, no. 4 (October 2009): R913—R924. http://dx.doi.org/10.1152/ajpregu.91053.2008.

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Storage of fatty acids as triacylglycerol (TAG) occurs in almost all mammalian tissues. Whereas adipose tissue is by far the largest storage site of fatty acids as TAG, subcellular TAG-containing structures—referred to as lipid droplets (LD)—are also present in other tissues. Until recently, LD were considered inert storage sites of energy dense fats. Nowadays, however, LD are increasingly considered dynamic functional organelles involved in many intracellular processes like lipid metabolism, vesicle trafficking, and cell signaling. Next to TAG, LD also contain other neutral lipids such as diacylglycerol. Furthermore, LD are coated by a monolayer of phospholipids decorated with a variety of proteins regulating the delicate balance between LD synthesis, growth, and degradation. Disturbances in LD-coating proteins may result in disequilibrium of TAG synthesis and degradation, giving rise to insulin-desensitizing lipid intermediates, especially in insulin-responsive tissues like skeletal muscle. For a proper and detailed understanding, more information on processes and players involved in LD synthesis and degradation is necessary. This, however, is hampered by the fact that research on LD dynamics in (human) muscle is still in its infancy. A rapidly expanding body of knowledge on LD dynamics originates from studies in other tissues and other species. Here, we aim to review the involvement of LD-coating proteins in LD formation and degradation (LD dynamics) and to extrapolate this knowledge to human skeletal muscle and to explore the role of LD dynamics in myocellular insulin sensitivity.

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30

Fu, Yuhua, Ningxie Chen, Ziying Wang, Shouqing Luo, Yu Ding, and Boxun Lu. "Degradation of lipid droplets by chimeric autophagy-tethering compounds." Cell Research 31, no. 9 (July 8, 2021): 965–79. http://dx.doi.org/10.1038/s41422-021-00532-7.

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AbstractDegrading pathogenic proteins by degrader technologies such as PROTACs (proteolysis-targeting chimeras) provides promising therapeutic strategies, but selective degradation of non-protein pathogenic biomolecules has been challenging. Here, we demonstrate a novel strategy to degrade non-protein biomolecules by autophagy-tethering compounds (ATTECs), using lipid droplets (LDs) as an exemplar target. LDs are ubiquitous cellular structures storing lipids and could be degraded by autophagy. We hypothesized that compounds interacting with both the LDs and the key autophagosome protein LC3 may enhance autophagic degradation of LDs. We designed and synthesized such compounds by connecting LC3-binding molecules to LD-binding probes via a linker. These compounds were capable of clearing LDs almost completely and rescued LD-related phenotypes in cells and in two independent mouse models with hepatic lipidosis. We further confirmed that the mechanism of action of these compounds was mediated through LC3 and autophagic degradation. Our proof-of-concept study demonstrates the capability of degrading LDs by ATTECs. Conceptually, this strategy could be applied to other protein and non-protein targets.

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31

Horowitz, A. D., B. Moussavian, and J. A. Whitsett. "Roles of SP-A, SP-B, and SP-C in modulation of lipid uptake by pulmonary epithelial cells in vitro." American Journal of Physiology-Lung Cellular and Molecular Physiology 270, no. 1 (January 1, 1996): L69—L79. http://dx.doi.org/10.1152/ajplung.1996.270.1.l69.

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The effects of the surfactant proteins (SP)-A, SP-B, and SP-C on binding and endocytosis of fluorescently labeled lipid vesicles were studied in rat type II epithelial cells and in MLE-12 cells, a pulmonary adenocarcinoma cell line with alveolar cell characteristics. Incorporation of SP-C in lipid vesicles markedly stimulated binding to the cell membrane at 4 degrees C and endocytosis of lipids at 37 degrees C. SP-C enhanced lipid uptake in MLE-12 cells, type II cells, and NIH 3T3 cells. SP-B stimulated lipid uptake in MLE-12 cells, but to a lesser degree. SP-B decreased the amount of lipid uptake stimulated by SP-C, SP-A did not increase endocytosis of lipids by MLE-12 cells or type II cells, but aggregates of lipid were observed associated with the cell surface in the presence of SP-A. Maintenance of active surfactant in the lung may be achieved through the selective uptake and degradation of surfactant subfractions depleted in SP-A and SP-B.

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32

Breiden, Bernadette, and Konrad Sandhoff. "Emerging mechanisms of drug-induced phospholipidosis." Biological Chemistry 401, no. 1 (December 18, 2019): 31–46. http://dx.doi.org/10.1515/hsz-2019-0270.

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Abstract Drug-induced phospholipidosis is a lysosomal storage disorder characterized by excessive accumulation of phospholipids. Its cellular mechanism is still not well understood, but it is known that cationic amphiphilic drugs can induce it. These drugs have a hydrophilic amine head group that can be protonated in the endolysosomal compartment. As cationic amphiphiles, they are trapped in lysosomes, where they interfere with negatively charged intralysosomal vesicles, the major platforms of cellular sphingolipid degradation. Metabolic principles observed in sphingolipid and phospholipid catabolism and inherited sphingolipidoses are of great importance for lysosomal function and physiological lipid turnover at large. Therefore, we also propose intralysosomal vesicles as major platforms for degradation of lipids and phospholipids reaching them by intracellular pathways like autophagy and endocytosis. Phospholipids are catabolized as components of vesicle surfaces by protonated, positively charged phospholipases, electrostatically attracted to the negatively charged vesicles. Model experiments suggest that progressively accumulating cationic amphiphilic drugs inserting into the vesicle membrane with their hydrophobic molecular moieties disturb and attenuate the main mechanism of lipid degradation as discussed here. By compensating the negative surface charge, cationic enzymes are released from the surface of vesicles and proteolytically degraded, triggering a progressive lipid storage and the formation of inactive lamellar bodies.

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Mimi, Carolina Ovile, Marília Caixeta Sousa, Patrícia Luciana Carriel Corrêa, Ivan De-la-Cruz-Chacón, Carmen Sílvia Fernandes Boaro, and Gisela Ferreira. "Impact of GA3 on Sugar and Lipid Degradation during Annona x atemoya Mabb. Seed Germination." Horticulturae 9, no. 3 (March 16, 2023): 388. http://dx.doi.org/10.3390/horticulturae9030388.

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Gibberellins act to overcome dormancy and increase the germination rate of seeds of several species, including the genus Annona. Considering that Annona seeds have a high lipid content and have few sugars, the degradation of such reserves from the application of gibberellins has not been described so far. This study aimed to evaluate how the application of different gibberellic acid (GA3) concentrations acts on the sugar and lipid degradation pattern during the germination of atemoya seeds (Annona x atemoya Mabb.). Therefore, two experiments were carried out, one to evaluate the effect of GA3 on the germination process and another to evaluate the degradation of the reserves. To study the effect of GA3 on germinability, four treatments with GA3 concentrations of 0, 250, 500, and 1000 mg L−1 were used. To study the degradation of reserves, the four GA3 concentrations and five collection times were used (dry seed; seed with 1 day, 5 days, and 10 days of water acquisition; and seeds with primary root emission). Atemoya seeds showed an increase in germinability and changes in the sugar and lipid degradation pattern during the germination process in response to the treatments with GA3. Lipid and sugar degradation was observed from 24 h after seed immersion in GA3. The highest GA3 concentrations (500 and 1000 mg L−1) led to increases of 25% and 20%, respectively, in the germination rate, intensification of lipid degradation in seeds with primary root emission, and a decrease in sugar concentration until the 5th day.

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34

Lu, Jing, Zhuoqun Meng, Yan Chen, Liangli Yu, Boyan Gao, Yangjie Zheng, and Shuang Guan. "Apigenin induced autophagy and stimulated autophagic lipid degradation." Food & Function 11, no. 10 (2020): 9208–15. http://dx.doi.org/10.1039/d0fo00949k.

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35

Panaser, Amandeep, and Brian J. Tighe. "Tear lipid degradation during overnight contact lens wear." Contact Lens and Anterior Eye 34 (December 2011): S14. http://dx.doi.org/10.1016/s1367-0484(11)60070-2.

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36

Farquharson, Kathleen L. "A Lipid Droplet-Associated Degradation System in Plants." Plant Cell 30, no. 9 (August 15, 2018): 1952–53. http://dx.doi.org/10.1105/tpc.18.00610.

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37

SUGIMORI, Daisuke, Masatoshi NAKAMURA, and Yuma MIHARA. "Microbial Degradation of Lipid byAcinetobactersp. Strain SOD-1." Bioscience, Biotechnology, and Biochemistry 66, no. 7 (January 2002): 1579–82. http://dx.doi.org/10.1271/bbb.66.1579.

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38

Van Bilsen, Danielle G. J. L., Tineke van Roekel, and Folkert A. Hoekstra. "Declining viability and lipid degradation during pollen storage." Sexual Plant Reproduction 7, no. 5 (September 1994): 303–10. http://dx.doi.org/10.1007/bf00227714.

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39

Scriba, Gerhard K. E. "Synthesis andin Vitro Degradation of Testosterone-Lipid Conjugates." Archiv der Pharmazie 328, no. 3 (1995): 271–76. http://dx.doi.org/10.1002/ardp.19953280313.

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40

Quach, Hung, Tuong-Vi Le, Thanh-Thuy Nguyen, Phuong Nguyen, Cuu Khoa Nguyen, and Le Hang Dang. "Nano-Lipids Based on Ginger Oil and Lecithin as a Potential Drug Delivery System." Pharmaceutics 14, no. 8 (August 9, 2022): 1654. http://dx.doi.org/10.3390/pharmaceutics14081654.

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Lipid nanoparticles based on lecithin are an interesting part of drug delivery systems. However, the stability of lecithin nano-lipids is problematic due to the degradation of lecithin, causing a decrease in pH. In this study, the modification of the conventional nano-lipid-based soybean lecithin was demonstrated. Ginger-oil-derived Zingiber officinale was used along with lecithin, cholesterol and span 80 to fabricate nano-lipids (GL nano-lipids) using a thin-film method. TEM and a confocal microscope were used to elucidate GL nano-lipids’ liposome-like morphology. The average size of the resultant nano-lipid was 249.1 nm with monodistribution (PDI = 0.021). The ζ potential of GL nano-lipids was negative, similarly to as-prepared nano-lipid-based lecithin. GL nano-lipid were highly stable over 60 days of storage at room temperature in terms of size and ζ potential. A shift in pH value from alkaline to acid was detected in lecithin nano-lipids, while with the incorporation of ginger oil, the pH value of nano-lipid dispersion was around 7.0. Furthermore, due to the richness of shogaol-6 and other active compounds in ginger oil, the GL nano-lipid was endowed with intrinsic antibacterial activity. In addition, the sulforhodamine B (SRB) assay and live/dead imaging revealed the excellent biocompatibility of GL nano-lipids. Notably, GL nano-lipids were capable of carrying hydrophobic compounds such as curcumin and performed a pH-dependent release profile. A subsequent characterization showed their suitable potential for drug delivery systems.

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41

Bersuker, Kirill, and James A. Olzmann. "Establishing the lipid droplet proteome: Mechanisms of lipid droplet protein targeting and degradation." Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids 1862, no. 10 (October 2017): 1166–77. http://dx.doi.org/10.1016/j.bbalip.2017.06.006.

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42

Merzlyak, Mark N., and G. A. F. Hendry. "Free radical metabolism, pigment degradation and lipid peroxidation in leaves during senescence." Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 102 (1994): 459–71. http://dx.doi.org/10.1017/s0269727000014482.

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SynopsisVarious lines of evidence suggest that the controlled increase in the production of oxygen radicals is an important factor involved in phytohormone metabolism, selective changes in membrane permeability, degradation of photosynthetic pigments and unsaturated membrane lipids, oxidative modification and subsequent proteolytic degradation, and other events occurring in ageing and senescing leaves. Increased lipid peroxidation, appearance of chlorophyll allomerised products, as well as fluorescent ‘lipofuscin-like’ pigments have been documented in different systems of leaf senescence. On the other hand, the accumulation of peroxidised products may result from the alteration to native structural organisation and energy dissipation reactions of the photosynthetic apparatus. Although there are contradictory and incomplete data on the activity of the systems involved in the metabolism of oxygen radicals, it seems that senescing leaves retain, at least in part, their defence potential against both activated oxygen species and toxic lipid peroxidation products. This provides the plant with the ability to successfully dismantle its photosynthetic apparatus during senescence in a relatively safe manner.

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Nguyen, Thi-Thao-Linh, and Van-An Duong. "Solid Lipid Nanoparticles." Encyclopedia 2, no. 2 (May 18, 2022): 952–73. http://dx.doi.org/10.3390/encyclopedia2020063.

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Solid lipid nanoparticles (SLNs) are produced from physiologically biocompatible lipids. They have been proven to improve solubility, cellular uptake, and stability, reduce enzyme degradation, and prolong the circulation time of various drugs. SLNs have been applied in the oral, parenteral, transdermal, intranasal, ocular, and pulmonary drug delivery of different drugs, with enhanced safety, bioavailability, and overall therapeutic effects. In this entry, the authors summarize the primary features of SLNs, methods to prepare SLNs, and recent applications of SLNs in drug delivery. Owing to their advantages, SLNs are potential drug delivery systems to improve the management of various diseases and will, soon, be available for clinical use.

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44

Murison, Victor, Josiane Hérault, Benoît Schoefs, Justine Marchand, and Lionel Ulmann. "Bioinformatics-Based Screening Approach for the Identification and Characterization of Lipolytic Enzymes from the Marine Diatom Phaeodactylum tricornutum." Marine Drugs 21, no. 2 (February 14, 2023): 125. http://dx.doi.org/10.3390/md21020125.

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Oleaginous diatoms accumulate lipids of biotechnological interest when exposed to nutrient stress conditions such as nitrogen starvation. While accumulation mechanisms are well-known and have been engineered to improve lipid production, degradation mechanisms remain poorly investigated in diatoms. Identifying lipid-degrading enzymes is the initial step to understanding the catabolic processes. In this study, an in silico screening of the genome of Phaeodactylum tricornutum led to the identification of 57 putative triacylglycerol lipases (EC 3.1.1.3) grouped in 4 families. Further analysis revealed the presence of conserved domains and catalytic residues of lipases. Physico-chemical characteristics and subcellular localization predictions highlighted that a majority of these putative proteins are hydrophilic and cytosolic, suggesting they could be recruited to lipid droplets directly from the cytosol. Among the 57 identified putative proteins, three lipases were identified as possibly involved in lipophagy due to a potential vacuolar localization. The expression of the mRNA corresponding to the 57 proteins was then searched in 3 transcriptomic datasets obtained under nitrogen starvation. Nine genes were highly regulated and were considered as encoding enzymes with a probable important function in lipid catabolism. A tertiary structure prediction of these nine candidates yielded eight functional 3D models. Among those, two downregulated enzymes, Phatr3_J54974 and Phatr3_EG00720, were highlighted as good targets for future functional genomics and purification studies to investigate their role in lipid degradation.

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45

Du, Xiaoli, Caroline Barisch, Peggy Paschke, Cornelia Herrfurth, Oliver Bertinetti, Nadine Pawolleck, Heike Otto, et al. "Dictyostelium Lipid Droplets Host Novel Proteins." Eukaryotic Cell 12, no. 11 (September 13, 2013): 1517–29. http://dx.doi.org/10.1128/ec.00182-13.

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ABSTRACT Across all kingdoms of life, cells store energy in a specialized organelle, the lipid droplet. In general, it consists of a hydrophobic core of triglycerides and steryl esters surrounded by only one leaflet derived from the endoplasmic reticulum membrane to which a specific set of proteins is bound. We have chosen the unicellular organism Dictyostelium discoideum to establish kinetics of lipid droplet formation and degradation and to further identify the lipid constituents and proteins of lipid droplets. Here, we show that the lipid composition is similar to what is found in mammalian lipid droplets. In addition, phospholipids preferentially consist of mainly saturated fatty acids, whereas neutral lipids are enriched in unsaturated fatty acids. Among the novel protein components are LdpA, a protein specific to Dictyostelium , and Net4, which has strong homologies to mammalian DUF829/Tmem53/NET4 that was previously only known as a constituent of the mammalian nuclear envelope. The proteins analyzed so far appear to move from the endoplasmic reticulum to the lipid droplets, supporting the concept that lipid droplets are formed on this membrane.

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46

Pisciotta, John M., Isabelle Coppens, Abhai K. Tripathi, Peter F. Scholl, Joel Shuman, Sunil Bajad, Vladimir Shulaev, and David J. Sullivan. "The role of neutral lipid nanospheres in Plasmodium falciparum haem crystallization." Biochemical Journal 402, no. 1 (January 25, 2007): 197–204. http://dx.doi.org/10.1042/bj20060986.

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The intraerythrocytic malaria parasite constructs an intracellular haem crystal, called haemozoin, within an acidic digestive vacuole where haemoglobin is degraded. Haem crystallization is the target of the widely used antimalarial quinoline drugs. The intracellular mechanism of molecular initiation of haem crystallization, whether by proteins, polar membrane lipids or by neutral lipids, has not been fully substantiated. In the present study, we show neutral lipid predominant nanospheres, which envelop haemozoin inside Plasmodium falciparum digestive vacuoles. Subcellular fractionation of parasite-derived haemozoin through a dense 1.7 M sucrose cushion identifies monoacylglycerol and diacylglycerol neutral lipids as well as some polar lipids in close association with the purified haemozoin. Global MS lipidomics detects monopalmitic glycerol and monostearic glycerol, but not mono-oleic glycerol, closely associated with haemozoin. The complex neutral lipid mixture rapidly initiates haem crystallization, with reversible pH-dependent quinoline inhibition associated with quinoline entry into the neutral lipid microenvironment. Neutral lipid nanospheres both enable haem crystallization in the presence of high globin concentrations and protect haem from H2O2 degradation. Conceptually, the present study shifts the intracellular microenvironment of haem crystallization and quinoline inhibition from a polar aqueous location to a non-polar neutral lipid nanosphere able to exclude water for efficient haem crystallization.

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47

Grebenteuch, Sandra, Lothar W. Kroh, Stephan Drusch, and Sascha Rohn. "Formation of Secondary and Tertiary Volatile Compounds Resulting from the Lipid Oxidation of Rapeseed Oil." Foods 10, no. 10 (October 12, 2021): 2417. http://dx.doi.org/10.3390/foods10102417.

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The lipid oxidation of fats and oils leads to volatile organic compounds, having a decisive influence on the sensory quality of foods. To understand formation and degradation pathways and to evaluate the suitability of lipid-derived aldehydes as marker substances for the oxidative status of foods, the formation of secondary and tertiary lipid oxidation compounds was investigated with gas chromatography in rapeseed oils. After 120 min, up to 65 compounds were detected. In addition to secondary degradation products, tertiary products such as alkyl furans, ketones, and aldol condensation products were also found. The comparison of rapeseed oils, differing in their initial peroxide values, showed that the formation rate of secondary compounds was higher in pre-damaged oils. Simultaneously, a faster degradation, especially of unsaturated aldehydes, was observed. Consequently, the formation of tertiary products (e.g., alkyl furans, aldol adducts) from well-known lipid oxidation products (i.e., propanal, hexanal, 2-hexenal, and 2-nonenal) was investigated in model systems. The experiments showed that these compounds form the new substances in subsequent reactions, especially, when other compounds such as phospholipids are present. Hexanal and propanal are suitable as marker compounds in the early phase of lipid oxidation, but at an advanced stage they are subject to aldol condensation. Consequently, the detection of tertiary degradation products needs to be considered in advanced lipid oxidation.

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48

Müllner, Heidemarie, and Günther Daum. "Dynamics of neutral lipid storage in yeast." Acta Biochimica Polonica 51, no. 2 (June 30, 2004): 323–47. http://dx.doi.org/10.18388/abp.2004_3574.

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Since energy storage is a basic metabolic process, the synthesis of neutral lipids occurs in all kingdoms of life. The yeast, Saccharomyces cerevisiae, widely accepted as a model eukaryotic cell, contains two classes of neutral lipids, namely steryl esters and triacylglycerols. Triacylglycerols are synthesized through two pathways governed by the acyl-CoA diacylglycerol acyltransferase Dga1p and the phospholipid diacylglycerol acyltransferase Lro1p, respectively. Steryl esters are formed by the two steryl ester synthases Are1p and Are2p, two enzymes with overlapping function which also catalyze triacylglycerol formation, although to a minor extent. Storage of neutral lipids is tightly linked to the biogenesis of so called lipid particles. The role of this compartment in lipid homeostasis and its interplay with other organelles involved in neutral lipid dynamics, especially the endoplasmic reticulum and the plasma membrane, are subject of current investigations. In contrast to neutral lipid formation, mobilization of triacylglycerols and steryl esters in yeast are less characterized at the molecular level. Only recently, the triacylglycerol lipase Tgl3p was identified as the first yeast enzyme of this kind by function. Genes and gene products governing steryl ester mobilization still await identification. Besides biochemical properties of enzymes involved in yeast neutral lipid synthesis and degradation, regulatory aspects of these pathways and cell biological consequences of neutral lipid depletion will be discussed in this minireview.

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49

Subhan, Md Abdus, Nina Filipczak, and Vladimir P. Torchilin. "Advances with Lipid-Based Nanosystems for siRNA Delivery to Breast Cancers." Pharmaceuticals 16, no. 7 (July 6, 2023): 970. http://dx.doi.org/10.3390/ph16070970.

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Breast cancer is the most frequently diagnosed cancer among women. Breast cancer is also the key reason for worldwide cancer-related deaths among women. The application of small interfering RNA (siRNA)-based drugs to combat breast cancer requires effective gene silencing in tumor cells. To overcome the challenges of drug delivery to tumors, various nanosystems for siRNA delivery, including lipid-based nanoparticles that protect siRNA from degradation for delivery to cancer cells have been developed. These nanosystems have shown great potential for efficient and targeted siRNA delivery to breast cancer cells. Lipid-based nanosystems remain promising as siRNA drug delivery carriers for effective and safe cancer therapy including breast cancer. Lipid nanoparticles (LNPs) encapsulating siRNA enable efficient and specific silencing of oncogenes in breast tumors. This review discusses a variety of lipid-based nanosystems including cationic lipids, sterols, phospholipids, PEG-lipid conjugates, ionizable liposomes, exosomes for effective siRNA drug delivery to breast tumors, and the clinical translation of lipid-based siRNA nanosystems for solid tumors.

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50

Lin, Penghui, Li Dai, Daniel R. Crooks, Leonard M. Neckers, Richard M. Higashi, Teresa W.-M. Fan, and Andrew N. Lane. "NMR Methods for Determining Lipid Turnover via Stable Isotope Resolved Metabolomics." Metabolites 11, no. 4 (March 29, 2021): 202. http://dx.doi.org/10.3390/metabo11040202.

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Lipids comprise diverse classes of compounds that are important for the structure and properties of membranes, as high-energy fuel sources and as signaling molecules. Therefore, the turnover rates of these varied classes of lipids are fundamental to cellular function. However, their enormous chemical diversity and dynamic range in cells makes detailed analysis very complex. Furthermore, although stable isotope tracers enable the determination of synthesis and degradation of complex lipids, the numbers of distinguishable molecules increase enormously, which exacerbates the problem. Although LC-MS-MS (Liquid Chromatography-Tandem Mass Spectrometry) is the standard for lipidomics, NMR can add value in global lipid analysis and isotopomer distributions of intact lipids. Here, we describe new developments in NMR analysis for assessing global lipid content and isotopic enrichment of mixtures of complex lipids for two cell lines (PC3 and UMUC3) using both 13C6 glucose and 13C5 glutamine tracers.

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