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1
Houdou, Marine, and François Foulquier. "Anomalies congénitales de la glycosylation (CDG)." médecine/sciences 36, no. 8-9 (August 2020): 735–46. http://dx.doi.org/10.1051/medsci/2020128.
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La glycosylation est un processus cellulaire complexe conduisant à des transferts successifs de monosaccharides sur une molécule acceptrice, le plus souvent une protéine ou un lipide. Ce processus est universel chez tous les organismes vivants et est très conservé au cours de l’évolution. Chez l’homme, des perturbations survenant au cours d’une ou plusieurs réactions de glycosylation sont à l’origine de glycopathologies génétiques rares, appelées anomalies congénitales de la glycosylation ou congenital disorders of glycosylation (CDG). Cette revue propose de revisiter ces CDG, de 1980 à aujourd’hui, en présentant leurs découvertes, leurs diagnostics, leurs causes biochimiques et les traitements actuellement disponibles.
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Ma, Chengye, Yuyan Fan, Shuhua Wu, Zhehao Zhang, and Dongliang Zhang. "Analysis of the Complex Index of Extruded Corn Starch and Degermed Corn." Journal of Food Research 6, no. 6 (October 29, 2017): 56. http://dx.doi.org/10.5539/jfr.v6n6p56.
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Commercial corn starch or degermed corn contains lipids and protein, and starch-lipid (or protein) complexes were formed during extrusion. The formation of starch and lipid (or protein) complexes was investigated using the complex index (CI) and differential scanning calorimetry (DSC) analysis. The CI of extrudates of a commercial corn starch/germ mixture (or gluten meal) showed that starch was complexed with lipid or protein, thus decreasing the iodine-binding capacity of amylose. The CI increased as the content of germ or gluten meal blending starch increased. Blends containing degermed corn and thermostable or mesophilic α-amylase were extruded. The CI of extrudates was higher than 55%; however, the starch-lipid complex was not stable and could be separated. The DSC analysis of the blending starch extrudate and palmitic acid showed that the enthalpy of the starch-palmitic acid complex was increased with increasing fatty acid content. Increased complex formation required more DSC heating, resulting in an enthalpy change of the endothermic peak rise, with the peak temperature higher than 100℃.
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WETZER, Barbara, Gerardo BYK, Marc FREDERIC, Marc AIRIAU, Francis BLANCHE, Bruno PITARD, and Daniel SCHERMAN. "Reducible cationic lipids for gene transfer." Biochemical Journal 356, no. 3 (June 8, 2001): 747–56. http://dx.doi.org/10.1042/bj3560747.
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One of the main challenges of gene therapy remains the increase of gene delivery into eukaryotic cells. We tested whether intracellular DNA release, an essential step for gene transfer, could be facilitated by using reducible cationic DNA-delivery vectors. For this purpose, plasmid DNA was complexed with cationic lipids bearing a disulphide bond. This reduction-sensitive linker is expected to be reduced and cleaved in the reducing milieu of the cytoplasm, thus potentially improving DNA release and consequently transfection. The DNA–disulphide-lipid complexation was monitored by ethidium bromide exclusion, and the size of complexes was determined by dynamic light scattering. It was found that the reduction kinetics of disulphide groups in DNA–lipid complexes depended on the position of the disulphide linker within the lipid molecule. Furthermore, the internal structure of DNA–lipid particles was examined by small-angle X-ray scattering before and after lipid reduction. DNA release from lipid complexes was observed after the reduction of disulphide bonds of several lipids. Cell-transfection experiments suggested that complexes formed with selected reducible lipids resulted in up to 1000-fold higher reporter-gene activity, when compared with their analogues without disulphide bonds. In conclusion, reduction-sensitive groups introduced into cationic lipid backbones potentially allow enhanced DNA release from DNA–lipid complexes after intracellular reduction and represent a tool for improved vectorization.
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Guo, Wenjin, and Robert J. Lee. "Efficient Gene Delivery Using Anionic Liposome-Complexed Polyplexes (LPDII)." Bioscience Reports 20, no. 5 (October 1, 2000): 419–32. http://dx.doi.org/10.1023/a:1010338219401.
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Synthetic gene transfer vectors based on polyplexes complexed to anionic liposomes (LPDII vectors) were characterized for their transfection efficiency in cultured mammalian cells. The effects of polycation to DNA ratio, lipid to DNA ratio, choice of polycation and lipid composition were systematically evaluated in human oral carcinoma KB cells, using a luciferase reporter gene. For LPDII formulations containing poly-L-lysine and dioeoylphosphatidylethanolamine/cholesteryl hemisuccinate (DOPE/CHEMS) anionic liposomes, at a constant lipid to DNA ratio, an increase in the polycation/DNA (N/P) ratio resulted in an increase in transfection activity. Meanwhile, the optimal lipid to DNA ratio for efficient gene delivery was influenced by the N/P ratio used, and was increased at higher N/P ratios. For the DNA condensing agent, poly-L-lysine could be replaced by polyethylenimine (PEI) as the DNA condensing agent in the formulations. For the lipidic components, CHEMS could be replaced by other anioniclipids including oleic acid, dicetylphosphate and phosphatidylserine, but DOPE, a fusogenic helper lipid, could not be replaced by dioleolyphosphatidylcholine. LPDII formulation showed significantly less cytotoxicity compared to the commonly used cationic lipsomes or PEI mediated transfection and several cell lines were transfected with high efficiency. LPDII vectors avoid the use of toxic cationic lipids and may have potential application in gene therapy.
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Krupa, Zbigniew. "Acyl lipids in the supramolecular chlorophyll-protein complexes of photosystems - isolation artifacts or integral components regulating their structure and functions?" Acta Societatis Botanicorum Poloniae 57, no. 3 (2014): 401–18. http://dx.doi.org/10.5586/asbp.1988.039.
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The precise nature of interactions between the chloropnyll-protein complexes related to photosystem I or photosystem II and the acyl lipids in the thylakoid membranes is not yet fully elucidated. Analyses of the lipid content of isolated photosystem supramolecular complexes reveal that they are integral components of these complexes. However, the relations between certain acyl lipids and the specific structure and functions of the complexes investigated are still widely discussed. The most generally accepted phenomenon is the fact of participation of phosphatidylglycerol containing the unique <em>trans-</em>Δ<sup>3</sup> -hexadecenoic acid in the oligomerization of the light-harvesting chlorophyll a/b protein complex II.
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Falcão, Mário Cícero. "Dinâmica da composição lipídica das fórmulas infantis e suas implicações clínicas." Braspen Journal 35, no. 3 (October 15, 2020): 294–306. http://dx.doi.org/10.37111/braspenj.2020353015.
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In human milk, the role of lipids as a source for the adequate growth and development of the infant is highlighted. The lipidic system of breast milk, responsible for approximately 50% of calories, is structured for the newborn and the infant. Digestion and absorption of lipids are facilitated by the organization of fat, the type of fatty acid (palmitic, oleic, linoleic, linolenic acids, etc.), the composition of triglycerides and the lipase stimulated by bile salts. In addition, milk contains docosahexaenoic acid, which allows optimal neurological and immunological development. Although the lipid structure of breast milk is extremely complex, it should serve as a model for the dynamics of the lipid composition of infant formulas. The addition of long-chain fatty acids (arachidonic and docosahexaenoic acids) linked to phospholipids in infant formulas can contribute to a better development of infants, as well as acting on the immune system and metabolic imprinting, reducing the risk of chronic non-communicable diseases. Infants receiving formulas with palmitic acid in theß-2 position have a higher lactobacillus count in the feces, when compared to those receiving formulas with palmitic acid in the ß-1 and ß-3 positions, promoting the maintenance of intestinal eubiosis. Infants receiving formulas with ß-2 palmitic acid present bone health similar to infants breastfeeding, as fecal calcium loss does not occur.
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Kushnerova, Natalya F., Yury A. Rakhmanin, Tatiana V. Momot, Rufina I. Mikhailova, Irina N. Ryzhova, Svetlana E. Fomenko, Vladimir G. Sprygin, et al. "Assessment of changes in blood plasma biochemical indices at hypercholesterol diet with a high fat load." Hygiene and sanitation 100, no. 6 (June 28, 2021): 617–22. http://dx.doi.org/10.47470/0016-9900-2021-100-6-617-622.
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Introduction. It was studied the lipid composition of the blood plasma of rats under the impact of a hyper cholesterol diet with a high fat load. It was carried out the prevention of disturbances in blood plasma biochemical parameters with a lipid complex from the tunic of the marine hydrobiont Halocynthia aurantium. Materials and methods. The experiment was carried outwith outbred male rats weighing 200 ± 3 g.The experimental model of a hyper cholesterol diet with a high fat load with the development of dyslipidemia was set up by feeding the animals with ahigh fat diet consisting of 2% cholesterol and 20% beef fat from the total diet. The animals were divided into the following groups of 10 rats each: group 1 - control (standard diet), group 2 - dyslipidemia (hypercholesterol diet with high fat load), group 3 - dyslipidemia + lipid complex from ascidia. Results. It was shown that the influence of the diet was accompanied by an increase in the amount of total lipids in the blood plasma of rats, cholesterol, low-density lipoproteins (LDL), as well as a decrease in total phospholipids and high-density lipoproteins (HDL), which is considered as an indicator of the formation of dyslipidemia. The contents of phospholipid lysofractions increased due to the activation of phospholipases. The amount of fatty acid esters and cholesterol esters decreased, which indicates the inhibition of esterification processes. The imbalance in the phospholipid spectrum of blood plasma occurred: the amount of metabolically active fractions required for the functioning of membrane-bound enzymes decreased. The addition of a lipid complex from the tunic of ascidian purple into the diet was accompanied by a pronounced prophylactic effect, which manifested itself in the normalization of the studied biochemical parameters. The lipid complex containing a wide range of “sea” phospholipids and polynonsaturated fatty acids of the n-3 type is an important basis for application as prophylactic in the conditions of a hypercholesterol diet with a high-fat load. Conclusion. Application of the lipidic complexes containing the “sea” lipids allocated from a tunic of the ascidian purple can be useful and perspective at a dislipidemiya and a hypercholesterolemia that will allow to carry out effective prevention of violations of metabolic reactions at influence of hyper high-calorie food.
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Cuevas-Zuviría, Bruno, Marina Mínguez-Toral, Araceli Díaz-Perales, María Garrido-Arandia, and Luis F. Pacios. "Structural Dynamics of the Lipid Antigen-Binding Site of CD1d Protein." Biomolecules 10, no. 4 (April 1, 2020): 532. http://dx.doi.org/10.3390/biom10040532.
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CD1 molecules present lipid antigens to T-cells in early stages of immune responses. Whereas CD1‒lipid‒T-cell receptors interactions are reasonably understood, molecular details on initial trafficking and loading of lipids onto CD1 proteins are less complete. We present a molecular dynamics (MD) study of human CD1d, the isotype that activates iNKT cells. MD simulations and calculations of properties and Poisson-Boltzmann electrostatic potentials were used to explore the dynamics of the antigen-binding domain of the apo-form, CD1d complexes with three lipid–antigens that activate iNKT cells and CD1d complex with GM2AP, a protein that assists lipid loading onto CD1 molecules in endosomes/lysosomes. The study was done at pH 7 and 4.5, values representative of strongly acidic environments in endosomal compartments. Our findings revealed dynamic features of the entrance to the hydrophobic channels of CD1d modulated by two α helices with sensitivity to the type of lipid. We also found lipid- and pH-dependent dynamic changes in three exposed tryptophans unique to CD1d among the five human CD1 isotypes. On the basis of modelled structures, our data also revealed external effects produced by the helper protein GM2AP only when it interacts in its open form, thus suggesting that the own assistant protein also adapts conformation to association with CD1d.
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Sarwal, Rashmi, S. N. Sanyal, and S. Khera. "Lipid metabolism inTrichuris globulosa(Nematoda)." Journal of Helminthology 63, no. 4 (December 1989): 287–97. http://dx.doi.org/10.1017/s0022149x00009160.
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ABSTRACTAdult males and females ofTrichuris globulosa, an intestinal nematode parasite of goats, were studied for their lipid composition, capability of incorporation of (Na)-1-14C-acetate into different lipid classes and the activity of certain key enzymes of lipid metabolism. The parasite possesses a large variety of lipids including certain complex lipids. These are phosphatidylcholine (PC), diphosphatidylglycerol (cardiolipin), lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE), phosphatidylserine (PS), phosphatidylinositol (PI), plasmalogens (choline+ethanolamine), mono-, di- and triacylglycerols, free and esterified cholesterol, non-esterified fatty acids (NEFA), gangliosides, cerebrosides (glycosyl ceramide) and sulphuric acid esters of cerebrosides (sulphatides). The females contain more lipids than males, particularly the acylglycerols and phospholipids, possibly to meet the energy requirement and structural entities for the daily production of large numbers of eggs. Incorporation studies of labelled substrate, sodium-1-14C acetate demonstrate that the adult female has extremely active mechanisms for biosynthesizing these lipids. Most of the labels are found in PC, PE, SM, acylglycerols, NEFA, gangliosides, cerebrosides and sulphatides. Cholesterol, although a minor component of the parasitic lipids, incorporates large amount of label and also undergoes fast turnover. Kinetic analysis of the incorporation by measuring the rate constant (k) and half life (t½) reveals that gangliosides are the fastest biosynthesizing and turning over lipids, although they constitute only 0·1% of the total lipids. The presence of important enzymes of lipid biosynthesis, glucose-6-phosphate dehydrogenase, malate dehydrogenase and hydroxymethyl glutaryl-CoA reductase and an enzyme of lipid ester hydrolysis, triacylglycerol lipase, is also established inT. globulosa. Michaelis-Menten kinetic characteristics of the parasitic enzymes (Km, Vmax, v and the first order rate constant, k) are comparable with those of rat liver homogenates.
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Grassi, Sara, Paola Giussani, Laura Mauri, Simona Prioni, Sandro Sonnino, and Alessandro Prinetti. "Lipid rafts and neurodegeneration: structural and functional roles in physiologic aging and neurodegenerative diseases." Journal of Lipid Research 61, no. 5 (December 23, 2019): 636–54. http://dx.doi.org/10.1194/jlr.tr119000427.
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Lipid rafts are small, dynamic membrane areas characterized by the clustering of selected membrane lipids as the result of the spontaneous separation of glycolipids, sphingolipids, and cholesterol in a liquid-ordered phase. The exact dynamics underlying phase separation of membrane lipids in the complex biological membranes are still not fully understood. Nevertheless, alterations in the membrane lipid composition affect the lateral organization of molecules belonging to lipid rafts. Neural lipid rafts are found in brain cells, including neurons, astrocytes, and microglia, and are characterized by a high enrichment of specific lipids depending on the cell type. These lipid rafts seem to organize and determine the function of multiprotein complexes involved in several aspects of signal transduction, thus regulating the homeostasis of the brain. The progressive decline of brain performance along with physiological aging is at least in part associated with alterations in the composition and structure of neural lipid rafts. In addition, neurodegenerative conditions, such as lysosomal storage disorders, multiple sclerosis, and Parkinson’s, Huntington’s, and Alzheimer’s diseases, are frequently characterized by dysregulated lipid metabolism, which in turn affects the structure of lipid rafts. Several events underlying the pathogenesis of these diseases appear to depend on the altered composition of lipid rafts. Thus, the structure and function of lipid rafts play a central role in the pathogenesis of many common neurodegenerative diseases.
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Fraering, Patrick, Isabella Imhof, Urs Meyer, Jean-Marc Strub, Alain van Dorsselaer, Christine Vionnet, and Andreas Conzelmann. "The GPI Transamidase Complex of Saccharomyces cerevisiae Contains Gaa1p, Gpi8p, and Gpi16p." Molecular Biology of the Cell 12, no. 10 (October 2001): 3295–306. http://dx.doi.org/10.1091/mbc.12.10.3295.
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Gpi8p and Gaa1p are essential components of the GPI transamidase that adds glycosylphosphatidylinositols (GPIs) to newly synthesized proteins. After solubilization in 1.5% digitonin and separation by blue native PAGE, Gpi8p is found in 430–650-kDa protein complexes. These complexes can be affinity purified and are shown to consist of Gaa1p, Gpi8p, and Gpi16p (YHR188c). Gpi16p is an essential N-glycosylated transmembrane glycoprotein. Its bulk resides on the lumenal side of the ER, and it has a single C-terminal transmembrane domain and a small C-terminal, cytosolic extension with an ER retrieval motif. Depletion of Gpi16p results in the accumulation of the complete GPI lipid CP2 and of unprocessed GPI precursor proteins. Gpi8p and Gpi16p are unstable if either of them is removed by depletion. Similarly, when Gpi8p is overexpressed, it largely remains outside the 430–650-kDa transamidase complex and is unstable. Overexpression of Gpi8p cannot compensate for the lack of Gpi16p. Homologues of Gpi16p are found in all eucaryotes. The transamidase complex is not associated with the Sec61p complex and oligosaccharyltransferase complex required for ER insertion and N-glycosylation of GPI proteins, respectively. When GPI precursor proteins or GPI lipids are depleted, the transamidase complex remains intact.
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Pengnam, Supusson, Praneet Opanasopit, Theerasak Rojanarata, Nattisa Ni-yomtham, Boon Ek Yingyongnarongkul, and Samarwadee Plianwong. "Niosomes Containing Spermine-Based Cationic Lipid with Different Linkers for siRNA Delivery." Key Engineering Materials 819 (August 2019): 169–74. http://dx.doi.org/10.4028/www.scientific.net/kem.819.169.
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Niosomes are a lipid nanoparticle which have been widely used as non-viral carrier for therapeutic DNA or siRNA. They are formulated from non-ionic surfactant and other helper lipids. The aim of this study were to formulate niosome containing spermine-based cationic lipid with different linkers and to evaluate the efficiency of siRNA delivery in cervical cancer cell (HeLa cell). The niosomes were formulated from cholesterol (Chol), Span 20 and different cationic lipid (Ay, By, Cy and Dy) at various molar ratios. The properties of niosomes and ability of niosome to complex with siRNA were characterized. The cellular uptake, gene silencing efficiency and cytotoxicity were also determined. From the results, niosomes formulated at Chol:Span20:lipid molar ratio of 2.5:2.5:2 showed positive zeta potential and they were in nanosize (<200 nm). The binding ability of cationic niosomes to siRNA depended on types of cationic lipid. Among niosome/siRNA complexes, the niosome By/siRNA complex provided the highest gene silencing efficiency at weight ratio of 20. The highest cellular uptake also obtained by using niosome By as a carrier. The cytotoxicity revealed that cationic niosomes had low toxicity (cell viability > 80%). In conclusion, the cationic niosomes prepared from Chol, Span 20 and spermine-based cationic lipids are able to complex with siRNA and suitable for siRNA delivery with low toxicity.
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Sahin, Cagla, Deseree J. Reid, Michael T. Marty, and Michael Landreh. "Scratching the surface: native mass spectrometry of peripheral membrane protein complexes." Biochemical Society Transactions 48, no. 2 (March 4, 2020): 547–58. http://dx.doi.org/10.1042/bst20190787.
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A growing number of integral membrane proteins have been shown to tune their activity by selectively interacting with specific lipids. The ability to regulate biological functions via lipid interactions extends to the diverse group of proteins that associate only peripherally with the lipid bilayer. However, the structural basis of these interactions remains challenging to study due to their transient and promiscuous nature. Recently, native mass spectrometry has come into focus as a new tool to investigate lipid interactions in membrane proteins. Here, we outline how the native MS strategies developed for integral membrane proteins can be applied to generate insights into the structure and function of peripheral membrane proteins. Specifically, native MS studies of proteins in complex with detergent-solubilized lipids, bound to lipid nanodiscs, and released from native-like lipid vesicles all shed new light on the role of lipid interactions. The unique ability of native MS to capture and interrogate protein–protein, protein–ligand, and protein–lipid interactions opens exciting new avenues for the study of peripheral membrane protein biology.
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Bender, Julian, and Carla Schmidt. "Mass spectrometry of membrane protein complexes." Biological Chemistry 400, no. 7 (June 26, 2019): 813–29. http://dx.doi.org/10.1515/hsz-2018-0443.
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Abstract Membrane proteins are key players in the cell. Due to their hydrophobic nature they require solubilising agents such as detergents or membrane mimetics during purification and, consequently, are challenging targets in structural biology. In addition, their natural lipid environment is crucial for their structure and function further hampering their analysis. Alternative approaches are therefore required when the analysis by conventional techniques proves difficult. In this review, we highlight the broad application of mass spectrometry (MS) for the characterisation of membrane proteins and their interactions with lipids. We show that MS unambiguously identifies the protein and lipid components of membrane protein complexes, unravels their three-dimensional arrangements and further provides clues of protein-lipid interactions.
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Nichols, Frank, and Baliram Maraj. "Relationship between Hydroxy Fatty Acids and Prostaglandin E2 in Gingival Tissue." Infection and Immunity 66, no. 12 (December 1, 1998): 5805–11. http://dx.doi.org/10.1128/iai.66.12.5805-5811.1998.
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ABSTRACT Bacterial hydroxy fatty acids and alpha-hydroxy fatty acids have been demonstrated in complex lipid extracts of subgingival plaque and gingival tissue. However, little is known about the relationship between these hydroxy fatty acids in plaque and gingival tissues or the significance of these complex lipids in promoting inflammatory periodontal disease. The present study determined the percentages of ester-linked and amide-linked hydroxy fatty acids in complex lipids recovered from plaque and gingival tissue samples and the relationship between bacterial hydroxy fatty acids and alpha-hydroxy fatty acids in the lipid extracts. To evaluate a potential role for these hydroxy fatty acids in inflammatory periodontal disease, gingival tissue samples were examined for a relationship between prostaglandin E2 (PGE2) and hydroxy fatty acids recovered in gingival lipid. This investigation demonstrated that alpha-hydroxy fatty acids are only ester linked in plaque lipids but are largely amide linked in gingival tissue lipids. Furthermore, the level of alpha-hydroxy fatty acid in gingival lipid is directly related to the level of the bacterial hydroxy fatty acid 3-OHiso-branched C17:0 (3-OH iC17:0) in the same lipid extract. However, the relationship between hydroxy fatty acids in gingival lipids does not parallel the fatty acid relationship observed in plaque lipids. Finally, alpha-hydroxy fatty acid levels in gingival tissue lipids correlate directly with the recovery of PGE2 in the same tissue samples. These results demonstrate that alpha-hydroxy fatty acid levels in gingival lipids are directly related to both 3-OH iC17:0 bacterial lipid levels and PGE2 levels. These results indicate that in periodontal tissues there are unusual host-parasite interactions involving penetration of bacterial lipid in association with an altered gingival lipid metabolism and prostaglandin synthesis.
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Brajtburg, J., and J. Bolard. "Carrier effects on biological activity of amphotericin B." Clinical Microbiology Reviews 9, no. 4 (October 1996): 512–31. http://dx.doi.org/10.1128/cmr.9.4.512.
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Amphotericin B (AmB), the drug of choice for the treatment of most systemic fungal infections, is marketed under the trademark Fungizone, as an AmB-deoxycholate complex suitable for intravenous administration. The association between AmB and deoxycholate is relatively weak; therefore, dissociation occurs in the blood. The drug itself interacts with both mammalian and fungal cell membranes to damage cells, but the greater susceptibility of fungal cells to its effects forms the basis for its clinical usefulness. The ability of the drug to form stable complexes with lipids has allowed the development of new formulations of AmB based on this property. Several lipid-based formulations of the drug which are more selective in damaging fungal or parasitic cells than mammalian cells and some of which also have a better therapeutic index than Fungizone have been developed. In vitro investigations have led to the conclusion that the increase in selectivity observed is due to the selective transfer of AmB from lipid complexes to fungal cells or to the higher thermodynamic stability of lipid formulations. Association with lipids modulates AmB binding to lipoproteins in vivo, thus influencing tissue distribution and toxicity. For example, lipid complexes of AmB can be internalized by macrophages, and the macrophages then serve as a reservoir for the drug. Furthermore, stable AmB-lipid complexes are much less toxic to the host than Fungizone and can therefore be administered in higher doses. Experimentally, the efficacy of AmB-lipid formulations compared with Fungizone depends on the animal model used. Improved therapeutic indices for AmB-lipid formations have been demonstrated in clinical trials, but the definitive trials leading to the selection of an optimal formulation and therapeutic regimen have not been done.
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Tietz, Stefanie, Michelle Leuenberger, Ricarda Höhner, Alice H. Olson, Graham R. Fleming, and Helmut Kirchhoff. "A proteoliposome-based system reveals how lipids control photosynthetic light harvesting." Journal of Biological Chemistry 295, no. 7 (January 12, 2020): 1857–66. http://dx.doi.org/10.1074/jbc.ra119.011707.
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Integral membrane proteins are exposed to a complex and dynamic lipid environment modulated by nonbilayer lipids that can influence protein functions by lipid-protein interactions. The nonbilayer lipid monogalactosyldiacylglycerol (MGDG) is the most abundant lipid in plant photosynthetic thylakoid membranes, but its impact on the functionality of energy-converting membrane protein complexes is unknown. Here, we optimized a detergent-based reconstitution protocol to develop a proteoliposome technique that incorporates the major light-harvesting complex II (LHCII) into compositionally well-defined large unilamellar lipid bilayer vesicles to study the impact of MGDG on light harvesting by LHCII. Using steady-state fluorescence spectroscopy, CD spectroscopy, and time-correlated single-photon counting, we found that both chlorophyll fluorescence quantum yields and fluorescence lifetimes clearly indicate that the presence of MGDG in lipid bilayers switches LHCII from a light-harvesting to a more energy-quenching mode that dissipates harvested light into heat. It is hypothesized that in the in vitro system developed here, MGDG controls light harvesting of LHCII by modulating the hydrostatic lateral membrane pressure profile in the lipid bilayer sensed by LHCII-bound peripheral pigments.
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Odendall, Fenja, Sandra Backes, Takashi Tatsuta, Uri Weill, Maya Schuldiner, Thomas Langer, Johannes M. Herrmann, Doron Rapaport, and Kai Stefan Dimmer. "The mitochondrial intermembrane space–facing proteins Mcp2 and Tgl2 are involved in yeast lipid metabolism." Molecular Biology of the Cell 30, no. 21 (October 1, 2019): 2681–94. http://dx.doi.org/10.1091/mbc.e19-03-0166.
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Mitochondria are unique organelles harboring two distinct membranes, the mitochondrial inner and outer membrane (MIM and MOM, respectively). Mitochondria comprise only a subset of metabolic pathways for the synthesis of membrane lipids; therefore most lipid species and their precursors have to be imported from other cellular compartments. One such import process is mediated by the ER mitochondria encounter structure (ERMES) complex. Both mitochondrial membranes surround the hydrophilic intermembrane space (IMS). Therefore, additional systems are required that shuttle lipids between the MIM and MOM. Recently, we identified the IMS protein Mcp2 as a high-copy suppressor for cells that lack a functional ERMES complex. To understand better how mitochondria facilitate transport and biogenesis of lipids, we searched for genetic interactions of this suppressor. We found that MCP2 has a negative genetic interaction with the gene TGL2 encoding a neutral lipid hydrolase. We show that this lipase is located in the intermembrane space of the mitochondrion and is imported via the Mia40 disulfide relay system. Furthermore, we show a positive genetic interaction of double deletion of MCP2 and PSD1, the gene encoding the enzyme that synthesizes the major amount of cellular phosphatidylethanolamine. Finally, we demonstrate that the nucleotide-binding motifs of the predicted atypical kinase Mcp2 are required for its proper function. Taken together, our data suggest that Mcp2 is involved in mitochondrial lipid metabolism and an increase of this involvement by overexpression suppresses loss of ERMES.
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Wang, Ming, John A. Zuris, Fantao Meng, Holly Rees, Shuo Sun, Pu Deng, Yong Han, et al. "Efficient delivery of genome-editing proteins using bioreducible lipid nanoparticles." Proceedings of the National Academy of Sciences 113, no. 11 (February 29, 2016): 2868–73. http://dx.doi.org/10.1073/pnas.1520244113.
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A central challenge to the development of protein-based therapeutics is the inefficiency of delivery of protein cargo across the mammalian cell membrane, including escape from endosomes. Here we report that combining bioreducible lipid nanoparticles with negatively supercharged Cre recombinase or anionic Cas9:single-guide (sg)RNA complexes drives the electrostatic assembly of nanoparticles that mediate potent protein delivery and genome editing. These bioreducible lipids efficiently deliver protein cargo into cells, facilitate the escape of protein from endosomes in response to the reductive intracellular environment, and direct protein to its intracellular target sites. The delivery of supercharged Cre protein and Cas9:sgRNA complexed with bioreducible lipids into cultured human cells enables gene recombination and genome editing with efficiencies greater than 70%. In addition, we demonstrate that these lipids are effective for functional protein delivery into mouse brain for gene recombination in vivo. Therefore, the integration of this bioreducible lipid platform with protein engineering has the potential to advance the therapeutic relevance of protein-based genome editing.
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Brockman, Howard L., William E. Momsen, and Takahiro Tsujita. "Lipid-lipid complexes: Properties and effects on lipase binding to surfaces." Journal of the American Oil Chemists' Society 65, no. 6 (June 1988): 891–96. http://dx.doi.org/10.1007/bf02544505.
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Caudron, E., J. Y. Zhou, P. England, M. Ollivon, and P. Prognon. "Some Insights about 1,6-Diphenyl-1,3,5-hexatriene—Lipid Supramolecular Assemblies by Steady-State Fluorescence Measurements." Applied Spectroscopy 61, no. 9 (September 2007): 963–69. http://dx.doi.org/10.1366/000370207781745937.
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1,6-Diphenyl-1,3,5-hexatriene (DPH) is the most widely proposed molecular probe for the post-column fluorescence derivatization of lipids after liquid chromatography separation. This kind of detection consists of a supramolecular combination of DPH and eluted lipids. The detection is optimally performed in a mainly aqueous environment (over 80% v/v) because the weak fluorescence of DPH in water is drastically enhanced upon formation of supramolecular assemblies with lipids. In the present study, and in order to obtain better spectroscopic insights into the nature of these supramolecular assemblies, two different lipids were tested, 1,2,3-tridodecanoylglycerol (LLL) as a model triglyceride (nonpolar lipid) and dimyristoylphosphatidylcholine (DMPC) as a model phosphatidylcholine (charged amphiphilic lipid). Stoichiometry and association constants were determined on the basis of the variation of fluorescence intensity in the presence of various concentrations of lipids. LLL60–DPH2 and DMPC200–DPH2 complexes were identified with association constants as high as K2 = (5.8 × 0.5) × 1013 M−2 and (17.3 × 2.0) × 1013 M−2 for LLL and DMPC, respectively. The fluorescence intensity of DPH in the presence of LLL is greater than in the presence of DMPC. An attempt to characterize the insertion mode of DPH in the lipidic supramolecular assemblies is also made.
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Zhang, Cuiping, Ke Wang, Lujie Yang, Ronghua Liu, Yiwei Chu, Xue Qin, Pengyuan Yang, and Hongxiu Yu. "Lipid metabolism in inflammation-related diseases." Analyst 143, no. 19 (2018): 4526–36. http://dx.doi.org/10.1039/c8an01046c.
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Lipidomics is used to describe the complete lipid profile and network of cellular lipid metabolism. Traditionally, lipids are recognized as general membrane construction and energy storage molecules. Now, lipids are regarded as potent signaling molecules that regulate a multitude of cellular responses.
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Gaunt, Eleanor R., Qifeng Zhang, Winsome Cheung, Michael J. O. Wakelam, Andrew M. L. Lever, and Ulrich Desselberger. "Lipidome analysis of rotavirus-infected cells confirms the close interaction of lipid droplets with viroplasms." Journal of General Virology 94, no. 7 (July 1, 2013): 1576–86. http://dx.doi.org/10.1099/vir.0.049635-0.
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Rotaviruses (RVs) cause acute gastroenteritis in infants and young children, and are globally distributed. Within the infected host cell, RVs establish replication complexes in viroplasms (‘viral factories’) to which lipid droplet organelles are recruited. To further understand this recently discovered phenomenon, the lipidomes of RV-infected and uninfected MA104 cells were investigated. Cell lysates were subjected to equilibrium ultracentrifugation through iodixanol gradients. Fourteen different classes of lipids were differentiated by mass spectrometry. The concentrations of virtually all lipids were elevated in RV-infected cells. Fractions of low density (1.11–1.15 g ml−1), in which peaks of the RV dsRNA genome and lipid droplet- and viroplasm-associated proteins were observed, contained increased amounts of lipids typically found concentrated in the cellular organelle lipid droplets, confirming the close interaction of lipid droplets with viroplasms. A decrease in the ratio of the amounts of surface to internal components of lipid droplets upon RV infection suggested that the lipid droplet–viroplasm complexes became enlarged.
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YAMAOKA, Kanji, and Naoya OGATA. "Effect of Lipids on Physical Properties of DNA-Lipid Complexes." KOBUNSHI RONBUNSHU 61, no. 7 (2004): 384–90. http://dx.doi.org/10.1295/koron.61.384.
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Cascianelli, Giacomo, Maristella Villani, Marcello Tosti, Francesca Marini, Elisa Bartoccini, Mariapia Viola Magni, and Elisabetta Albi. "Lipid Microdomains in Cell Nucleus." Molecular Biology of the Cell 19, no. 12 (December 2008): 5289–95. http://dx.doi.org/10.1091/mbc.e08-05-0517.
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It is known that nuclear lipids play a role in proliferation, differentiation, and apoptotic process. Cellular nuclei contain high levels of phosphatidylcholine and sphingomyelin, which are partially linked with cholesterol and proteins to form lipid–protein complexes. These lipids are also associated with transcription factors and newly synthesized RNA but, up to date, their organization is still unknown. The aim of the present work was to study if these specific lipid–protein interactions could be nuclear membrane microdomains and to evaluate their possible role. The results obtained demonstrate for the first time the existence of nuclear microdomains characterized by a specific lipid composition similar to that of intranuclear lipid–protein complexes previously described. Nuclear microdomain lipid composition changes during cell proliferation when the content of newly synthesized RNA increases. Because previous data show a correlation between nuclear lipids and transcription process, the role of nuclear microdomains in cellular functions is discussed.
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Aoun, Manar, Christine Feillet-Coudray, Gilles Fouret, Béatrice Chabi, David Crouzier, Carla Ferreri, Chryssostomos Chatgilialoglu, et al. "Rat liver mitochondrial membrane characteristics and mitochondrial functions are more profoundly altered by dietary lipid quantity than by dietary lipid quality: effect of different nutritional lipid patterns." British Journal of Nutrition 107, no. 5 (July 20, 2011): 647–59. http://dx.doi.org/10.1017/s000711451100331x.
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Dietary lipids are known to affect the composition of the biological membrane and functions that are involved in cell death and survival. The mitochondrial respiratory chain enzymes are membrane protein complexes whose function depends on the composition and fluidity of the mitochondrial membrane lipid. The present study aimed at investigating the impact of different nutritional patterns of dietary lipids on liver mitochondrial functions. A total of forty-eight Wistar male rats were divided into six groups and fed for 12 weeks with a basal diet, lard diet or fish oil diet, containing either 50 or 300 g lipid/kg. The 30 % lipid intake increased liver NEFA, TAG and cholesterol levels, increased mitochondrial NEFA and TAG, and decreased phospholipid (PL) levels. SFA, PUFA and unsaturation index (UI) increased, whereas MUFA andtrans-fatty acids (FA) decreased in the mitochondrial membrane PL in 30 % fat diet-fed rats compared with 5 % lipid diet-fed rats. PL UI increased with fish oil dietv.basal and lard-rich diets, and PLtrans-FA increased with lard dietv.basal and fish oil diets. The 30 % lipid diet intake increased mitochondrial membrane potential, membrane fluidity, mitochondrial respiration and complex V activity, and decreased complex III and IV activities. With regard to lipid quality effects, β-oxidation decreased with the intake of basal or fish oil diets compared with that of the lard diet. The intake of a fish oil diet decreased complex III and IV activities compared with both the basal and lard diets. In conclusion, the characteristics and mitochondrial functions of the rat liver mitochondrial membrane are more profoundly altered by the quantity of dietary lipid than by its quality, which may have profound impacts on the pathogenesis and development of non-alcoholic fatty liver disease.
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Mishra, Vinod K., and Gattadahalli M. Anantharamaiah. "High-Resolution Structural Studies Elucidate Antiatherogenic and Anti-Inflammatory Properties of Peptides Designed to Mimic Amphipathic α-Helical Domains of Apolipoprotein A-I." Natural Product Communications 14, no. 5 (May 2019): 1934578X1984913. http://dx.doi.org/10.1177/1934578x19849131.
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Peptides designed to mimic the antiatherogenic and anti-inflammatory properties of apolipoprotein A-I show that although lipid association is required, not all lipid-associating peptides exhibit these properties. Our studies of a series of peptides showed that peptides with aromatic residues at the center of the nonpolar face were able to interact with inflammatory lipids and inhibited inflammation, which resulted in the amelioration of several lipid-mediated disorders such as lesion development, tumor formation, and Alzheimer’s plaque formation. The p K a values determined using 13C nuclear magnetic resonance (NMR) spectroscopy of K residues located at the polar-nonpolar interface provided the first clue to the relative orientations of the peptide helices with respect to each other and around the edge of the lipid discoidal complexes. High-resolution 1H-NMR studies of peptide-lipid discoidal complex confirmed the amphipathic α-helical structure of the peptide, location of aromatic residues of the peptide closer to the polar-nonpolar interface, and head-to-tail arrangement of the peptide helices around the edge of the disc. Amphipathic α-helical structure and the location of aromatic residues (F, W, Y) closer to the polar-nonpolar interface in a lipid environment allow the peptide to strongly bind oxidized lipids resulting in its anti-inflammatory properties.
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Ye, Yujin, Tianfu Wu, Ting Zhang, Jie Han, Deena Habazi, Ramesh Saxena, and Chandra Mohan. "Elevated oxidized lipids, anti-lipid autoantibodies and oxidized lipid immune complexes in active SLE." Clinical Immunology 205 (August 2019): 43–48. http://dx.doi.org/10.1016/j.clim.2019.05.004.
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Afshinnia, Farsad, Thekkelnaycke M. Rajendiran, Tanu Soni, Jaeman Byun, Stefanie Wernisch, Kelli M. Sas, Jennifer Hawkins, et al. "Impaired β-Oxidation and Altered Complex Lipid Fatty Acid Partitioning with Advancing CKD." Journal of the American Society of Nephrology 29, no. 1 (October 11, 2017): 295–306. http://dx.doi.org/10.1681/asn.2017030350.
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Studies of lipids in CKD, including ESRD, have been limited to measures of conventional lipid profiles. We aimed to systematically identify 17 different lipid classes and associate the abundance thereof with alterations in acylcarnitines, a metric of β-oxidation, across stages of CKD. From the Clinical Phenotyping Resource and Biobank Core (CPROBE) cohort of 1235 adults, we selected a panel of 214 participants: 36 with stage 1 or 2 CKD, 99 with stage 3 CKD, 61 with stage 4 CKD, and 18 with stage 5 CKD. Among participants, 110 were men (51.4%), 64 were black (29.9%), and 150 were white (70.1%), and the mean (SD) age was 60 (16) years old. We measured plasma lipids and acylcarnitines using liquid chromatography-mass spectrometry. Overall, we identified 330 different lipids across 17 different classes. Compared with earlier stages, stage 5 CKD associated with a higher abundance of saturated C16–C20 free fatty acids (FFAs) and long polyunsaturated complex lipids. Long-chain–to–intermediate-chain acylcarnitine ratio, a marker of efficiency of β-oxidation, exhibited a graded decrease from stage 2 to 5 CKD (P<0.001). Additionally, multiple linear regression revealed that the long-chain–to–intermediate-chain acylcarnitine ratio inversely associated with polyunsaturated long complex lipid subclasses and the C16–C20 FFAs but directly associated with short complex lipids with fewer double bonds. We conclude that increased abundance of saturated C16–C20 FFAs coupled with impaired β-oxidation of FFAs and inverse partitioning into complex lipids may be mechanisms underpinning lipid metabolism changes that typify advancing CKD.
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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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Stevens, K. G., C. A. Bader, A. Sorvina, D. A. Brooks, S. E. Plush, and J. L. Morrison. "Imaging and lipidomics methods for lipid analysis in metabolic and cardiovascular disease." Journal of Developmental Origins of Health and Disease 8, no. 5 (July 12, 2017): 566–74. http://dx.doi.org/10.1017/s2040174417000496.
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Cardiometabolic diseases exhibit changes in lipid biology, which is important as lipids have critical roles in membrane architecture, signalling, hormone synthesis, homoeostasis and metabolism. However,Developmental Origins of Health and Diseasestudies of cardiometabolic disease rarely include analysis of lipids. This short review highlights some examples of lipid pathology and then explores the technology available for analysing lipids, focussing on the need to develop imaging modalities for intracellular lipids. Analytical methods for studying interactions between the complex endocrine and intracellular signalling pathways that regulate lipid metabolism have been critical in expanding our understanding of how cardiometabolic diseases develop in association with obesity and dietary factors. Biochemical methods can be used to generate detailed lipid profiles to establish links between lifestyle factors and metabolic signalling pathways and determine how changes in specific lipid subtypes in plasma and homogenized tissue are associated with disease progression. New imaging modalities enable the specific visualization of intracellular lipid traffic and distributionin situ. These techniques provide a dynamic picture of the interactions between lipid storage, mobilization and signalling, which operate during normal cell function and are altered in many important diseases. The development of methods for imaging intracellular lipids can provide a dynamic real-time picture of how lipids are involved in complex signalling and other cell biology pathways; and how they ultimately regulate metabolic function/homoeostasis during early development. Some imaging modalities have the potential to be adapted forin vivoapplications, and may enable the direct visualization of progression of pathogenesis of cardiometabolic disease after poor growth in early life.
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Dolganyuk, Vyacheslav, Anna Andreeva, Ekaterina Budenkova, Stanislav Sukhikh, Olga Babich, Svetlana Ivanova, Alexander Prosekov, and Elena Ulrikh. "Study of Morphological Features and Determination of the Fatty Acid Composition of the Microalgae Lipid Complex." Biomolecules 10, no. 11 (November 19, 2020): 1571. http://dx.doi.org/10.3390/biom10111571.
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Microalgae are rich in nutrients and biologically active substances such as proteins, carbohydrates, lipids, vitamins, pigments, phycobiliproteins, among others. The lipid composition of the microalgae Chlorella vulgaris, Arthrospira platensis, and Dunaliella salina was screened for the first time. The proposed method for purifying the lipid complex isolated from microalgae’s biomass involved dissolving the lipid-pigment complex in n-hexane for 4 h and stirring at 500 rpm. We found that the largest number of neutral lipids is contained in the biomass of microalgae Arthrospira platensis, fatty acids, polar lipids (glycerophospholipids), and unsaponifiable substances—in the biomass of microalgae Dunaliella salina, chlorophyll, and other impurities—in the biomass of microalgae Chlorella vulgaris. The developed method of purification of the fatty acid composition of the microalgae lipid complex confirmed the content of fatty acids in microalgae, which are of interest for practical use in the production of biologically active components. We also determined the potential of its use in the development of affordable technology for processing microalgae into valuable food and feed additives.
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Medina, Jessica, Vera van der Velpen, Tony Teav, Yann Guitton, Hector Gallart-Ayala, and Julijana Ivanisevic. "Single-Step Extraction Coupled with Targeted HILIC-MS/MS Approach for Comprehensive Analysis of Human Plasma Lipidome and Polar Metabolome." Metabolites 10, no. 12 (December 2, 2020): 495. http://dx.doi.org/10.3390/metabo10120495.
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Expanding metabolome coverage to include complex lipids and polar metabolites is essential in the generation of well-founded hypotheses in biological assays. Traditionally, lipid extraction is performed by liquid-liquid extraction using either methyl-tert-butyl ether (MTBE) or chloroform, and polar metabolite extraction using methanol. Here, we evaluated the performance of single-step sample preparation methods for simultaneous extraction of the complex lipidome and polar metabolome from human plasma. The method performance was evaluated using high-coverage Hydrophilic Interaction Liquid Chromatography-ESI coupled to tandem mass spectrometry (HILIC-ESI-MS/MS) methodology targeting a panel of 1159 lipids and 374 polar metabolites. The criteria used for method evaluation comprised protein precipitation efficiency, and relative MS signal abundance and repeatability of detectable lipid and polar metabolites in human plasma. Among the tested methods, the isopropanol (IPA) and 1-butanol:methanol (BUME) mixtures were selected as the best compromises for the simultaneous extraction of complex lipids and polar metabolites, allowing for the detection of 584 lipid species and 116 polar metabolites. The extraction with IPA showed the greatest reproducibility with the highest number of lipid species detected with the coefficient of variation (CV) < 30%. Besides this difference, both IPA and BUME allowed for the high-throughput extraction and reproducible measurement of a large panel of complex lipids and polar metabolites, thus warranting their application in large-scale human population studies.
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Mika, Adriana, Tomasz Sledzinski, and Piotr Stepnowski. "Current Progress of Lipid Analysis in Metabolic Diseases by Mass Spectrometry Methods." Current Medicinal Chemistry 26, no. 1 (March 14, 2019): 60–103. http://dx.doi.org/10.2174/0929867324666171003121127.
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Background: Obesity, insulin resistance, diabetes, and metabolic syndrome are associated with lipid alterations, and they affect the risk of long-term cardiovascular disease. A reliable analytical instrument to detect changes in the composition or structures of lipids and the tools allowing to connect changes in a specific group of lipids with a specific disease and its progress, is constantly lacking. Lipidomics is a new field of medicine based on the research and identification of lipids and lipid metabolites present in human organism. The primary aim of lipidomics is to search for new biomarkers of different diseases, mainly civilization diseases. Objective: We aimed to review studies reporting the application of mass spectrometry for lipid analysis in metabolic diseases. Method: Following an extensive search of peer-reviewed articles on the mass spectrometry analysis of lipids the literature has been discussed in this review article. Results: The lipid group contains around 1.7 million species; they are totally different, in terms of the length of aliphatic chain, amount of rings, additional functional groups. Some of them are so complex that their complex analyses are a challenge for analysts. Their qualitative and quantitative analysis of is based mainly on mass spectrometry. Conclusion: Mass spectrometry techniques are excellent tools for lipid profiling in complex biological samples and the combination with multivariate statistical analysis enables the identification of potential diagnostic biomarkers.
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Schipper, Lidewij, Gertjan van Dijk, and Eline M. van der Beek. "Milk lipid composition and structure; The relevance for infant brain development." OCL 27 (2020): 5. http://dx.doi.org/10.1051/ocl/2020001.
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The neurocognitive development of infants can be positively associated with breastfeeding exclusivity and duration. Differences in dietary lipid quality between human milk and infant milk formula may contribute to this effect. In this review, we describe some of the known differences between human milk and infant milk formula in lipid quality, including fatty acid composition, complex lipids in the milk fat globule membrane as well as the physical properties of lipids and lipid globules. We describe some of the underlying mechanism by which these aspects of lipid quality are thought to modulate infant brain development such as differences in the supply and/or the bioavailability of lipids, lipid bound components and peripheral organ derived neurodevelopmental signals to the infant brain after ingestion and on longer term.
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Harris, Macallister, James Dilisio, Hadley Gary, Edward Chan, D. Branch Moody, and Brendan Podell. "24780 Investigating the role of mycobacterial lipid antigens and CD1-restricted T cells in host-protective tuberculosis immunity using a guinea pig model." Journal of Clinical and Translational Science 5, s1 (March 2021): 114–15. http://dx.doi.org/10.1017/cts.2021.692.
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ABSTRACT IMPACT: Examining lipid immunity for Mycobacterium tuberculosis in a translatable Guinea pig model may serve as a critical foundation for the creation of an efficacious human lipid based vaccine against tuberculosis. OBJECTIVES/GOALS: CD1 is a group of glycoproteins on antigen-presenting cells (APCs) that present lipid antigens to T cells. Mycobacterium tuberculosis (Mtb) has a lipid-rich cell wall which is essential for the pathogenesis of tuberculosis. Our goal is to determine the frequency, phenotypes, and functionality of CD1 T cells against Mtb using the guinea pig model. METHODS/STUDY POPULATION: Guinea pigs serve as the best translational model for CD1 immunology as they have both group 1 and group 2 CD1 complexes, comparable to human CD1. We performed ex-vivo and in-vivo experiments to analyze lipid antigen-specific CD1 T cell responses with Mtb infection. Assays to detect lipid-specific CD1 T cell activation include cellular proliferation, cytotoxicity assays, and interferon-gamma (IFNγ) release assay (Elispot) using both synthetic and Mtb-derived lipids. We isolated and characterized CD1 T cells using tetramerized CD1 complexes loaded with specific Mtb lipids. Spatial interaction between lipid loaded CD1 APCs with CD1 T cells were demonstrated by immunohistochemistry (IHC). Lastly, we will investigate the impact of lipid-based immunology via knockdown and overexpression of CD1 complexes. RESULTS/ANTICIPATED RESULTS: The cytotoxicity assay demonstrated that the CD1b1 and CD1b3 complexes play roles in the presentation of Mtb lipids, specifically glucose monomycolate, and mycolic acid, as noted by T cell killing of fibroblasts that express specific CD1 complexes that can present Mtb lipids. Similarly, cellular proliferation exhibited lipid specific T cell proliferation. IFNγ production by the stimulated CD1-restricted T cells (Elispot) was weak indicating CD1 T cells may not produce IFNγ. IHC successfully showed CD1 APCs in lungs and spleens of infected guinea pigs. It is anticipated that knocking out CD1 expression will lead to impaired immunity, and increase severity of disease as noted by pathologic lesions/bacterial burden, and systemic spread; in contrast, CD1 enhancement will limit the severity of tuberculosis. DISCUSSION/SIGNIFICANCE OF FINDINGS: We characterized CD1 T cells in infected guinea pigs at the tissue level, demonstrating Mtb lipid immunology. As a result, we laid the groundwork for investigating whether augmenting lipid immunity in the guinea pig model will enhance immunity against tuberculosis. Fruition of such work may lead to the development of effective tuberculosis vaccines.
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SHI, Fuxin, Luc WASUNGU, Anita NOMDEN, Marc C. A. STUART, Evgeny POLUSHKIN, Jan B. F. N. ENGBERTS, and Dick HOEKSTRA. "Interference of poly(ethylene glycol)–lipid analogues with cationic-lipid-mediated delivery of oligonucleotides; role of lipid exchangeability and non-lamellar transitions." Biochemical Journal 366, no. 1 (August 15, 2002): 333–41. http://dx.doi.org/10.1042/bj20020590.
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Cationic liposomes are applied to transfer oligonucleotides (ODNs) into cells to regulate gene expression for gene therapeutic or cell biological purposes. In vivo, poly(ethylene glycol) (PEG)—lipid derivatives are employed to stabilize and prolong the circulation lifetime of nucleic acid-containing particles, and to improve targeting strategies. In this study, we have studied the effects of PEG—lipid analogues, i.e. PEG coupled to either phosphatidylethanolamine (PE) or ceramide, on cationic-lipid—DNA complex ('lipoplex') assembly and the mechanism of cationic-lipid-mediated delivery of ODNs in vitro. Inclusion of 10mol% PEG—PE in ODN lipoplexes inhibited their internalization in Chinese hamster ovary cells by more than 70%. The intracellular fraction remained entrapped in the endosomal/lysosomal pathway, and no release of ODNs was apparent. Similar observations were made for complexes prepared from liposomes that contained PEG—ceramides. Interestingly, delivery resumed when lipoplexes had been externally coated with PEG—ceramides. In this case, the kinetics of delivery were dependent on the length of the ceramide acyl chain, consistent with a requirement for the PEG—lipid to dissociate from the complex. Moreover, although the chemical nature of the PEG—ceramides distinctly affected the net internalization of the complexes, impediment of delivery was largely related to an inhibitory effect of the PEG—lipid on the release of ODNs from the endosomal compartment. Cryo-electron microscopy and small-angle X-ray scattering revealed that the PEG—lipids stabilize the lamellar phase of the lipoplexes, while their acyl-chain-length-dependent transfer from the complex enables adaptation of the hexagonal phase. Within the endosomal compartment, this transition appears to be instrumental in causing the dissociation and cytosolic release of the ODNs for their nuclear homing.
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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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Turner, R. J., J. Thompson, S. Sariban-Sohraby, and J. S. Handler. "Monoclonal antibodies as probes of epithelial membrane polarization." Journal of Cell Biology 101, no. 6 (December 1, 1985): 2173–80. http://dx.doi.org/10.1083/jcb.101.6.2173.
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Monoclonal antibodies directed against antigens in the apical plasma membrane of the toad kidney epithelial cell line A6 were produced to probe the phenomena that underlie the genesis and maintenance of epithelial polarity. Two of these antibodies, 17D7 and 18C3, were selected for detailed study here. 17D7 is directed against a 23-kD peptide found on both the apical and basolateral surfaces of the A6 epithelium whereas 18C3 recognizes a lipid localized to the apical membrane only. This novel observation of an apically localized epithelial lipid species indicates the existence of a specific sorting and insertion process for this, and perhaps other, epithelial plasma membrane lipids. The antibody-antigen complexes formed by both these monoclonal antibodies are rapidly internalized by the A6 cells, but only the 18C3-antigen complex is recycled to the plasma membrane. In contrast to the apical localization of the free antigen, however, the 18C3-antigen complex is recycled to both the apical and basolateral surface of the epithelium, which indicates that monoclonal antibody binding interferes in some way with the normal sorting process for this apical lipid antigen.
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Saiz, Leonor, Sanjoy Bandyopadhyay, and Michael L. Klein. "Towards an Understanding of Complex Biological Membranes from Atomistic Molecular Dynamics Simulations." Bioscience Reports 22, no. 2 (April 1, 2002): 151–73. http://dx.doi.org/10.1023/a:1020130420869.
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Computer simulation has emerged as a powerful tool for studying the structural and functional properties of complex biological membranes. In the last few years, the use of recently developed simulation methodologies and current generation force fields has permitted novel applications of molecular dynamics simulations, which have enhanced our understanding of the different physical processes governing biomembrane structure and dynamics. This review focuses on frontier areas of research with important biomedical applications. We have paid special attention to polyunsaturated lipids, membrane proteins and ion channels, surfactant additives in membranes, and lipid–DNA gene transfer complexes.
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Aldana, Julian, Adriana Romero-Otero, and Mónica P. Cala. "Exploring the Lipidome: Current Lipid Extraction Techniques for Mass Spectrometry Analysis." Metabolites 10, no. 6 (June 3, 2020): 231. http://dx.doi.org/10.3390/metabo10060231.
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In recent years, high-throughput lipid profiling has contributed to understand the biological, physiological and pathological roles of lipids in living organisms. Across all kingdoms of life, important cell and systemic processes are mediated by lipids including compartmentalization, signaling and energy homeostasis. Despite important advances in liquid chromatography and mass spectrometry, sample extraction procedures remain a bottleneck in lipidomic studies, since the wide structural diversity of lipids imposes a constrain in the type and amount of lipids extracted. Differences in extraction yield across lipid classes can induce a bias on down-stream analysis and outcomes. This review aims to summarize current lipid extraction techniques used for untargeted and targeted studies based on mass spectrometry. Considerations, applications, and limitations of these techniques are discussed when used to extract lipids in complex biological matrices, such as tissues, biofluids, foods, and microorganisms.
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Bodnar, O. I., H. B. Kovalska, O. Ya Lukashiv, and V. V. Grubinko. "ОЦІНКА БІОЛОГІЧНОЇ ДІЇ ЕЛЕМЕНТВМІСНИХ ЛІПІДНИХ КОМПЛЕКСІВ З CHLORELLA VULGARIS НА ФУНКЦІОНАЛЬНИЙ СТАН ЗДОРОВИХ ЩУРІВ." Scientific Issue Ternopil Volodymyr Hnatiuk National Pedagogical University. Series: Biology 80, no. 3-4 (December 1, 2020): 50–62. http://dx.doi.org/10.25128/2078-2357.20.3-4.7.
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Chlorella is one of the most promising species of algae, which is widely cultivated for the industrial production of nutraceuticals in the form of tablets or powder. The value of Chlorella is primarily due to the high content of proteins and lipids (51–58 % and 20–23 % of dry weight respectively), carotenoids and an almost complete set of vitamins. At the same time, in the process of cultivation, a method was developed to enrich algobiomass and its individual components (primarily the lipid fraction) with selenium, zinc, chromium, as important regulatory trace elements.
From chlorella, we obtained seleniumlipid, selenium-zinclipid and selenium-chromiumlipid complexes, and their constancy and structure were grounded by chromatographic and mass spectrometric analysis. After feeding healthy rats with a starch solution of selenium-zinclipid complex (1 ml of which contained 0.4 μg of selenium, 2.5 μg of zinc and 0.5 mg of lipids) and selenium-chromiumlipid complex (1 ml contained 1.85 μg of selenium, 1.1 μg of chromium, 0,45 mg of lipids), no signs of intoxication were found (total medium molecular peptides content was reduced to 1.5 times, the content of TBA-active products and diene conjugates were also decreased), antioxidant processes (increase of glutathione content and activity of glutathione peroxidase while reducing the functional role of catalase) were activated (by increasing of succinate dehydrogenase and cytochrome oxidase activity, glutamate dehydrogenase - the way of glutamate formation), which contributed to the successful functioning of the antioxidant system and maintenance of energy and metabolic homeostasis in the body.
The obtained results enable the use of biologically active additives from chlorella, enriched with trace elements Se (IV), Zn (II) and Cr (III), as promising therapeutic and prophylactic substances, which will contribute to the successful functioning of the antioxidant system, maintain energy metabolism and metabolism correction of pathological processes, which is the basis for further studies of the biological activity of the complexes under study.
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Kornmann, Benoît. "The endoplasmic reticulum-mitochondria encounter structure: coordinating lipid metabolism across membranes." Biological Chemistry 401, no. 6-7 (May 26, 2020): 811–20. http://dx.doi.org/10.1515/hsz-2020-0102.
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AbstractEndosymbiosis, the beginning of a collaboration between an archaeon and a bacterium and a founding step in the evolution of eukaryotes, owes its success to the establishment of communication routes between the host and the symbiont to allow the exchange of metabolites. As far as lipids are concerned, it is the host that has learnt the symbiont’s language, as eukaryote lipids appear to have been borrowed from the bacterial symbiont. Mitochondria exchange lipids with the rest of the cell at membrane contact sites. In fungi, the endoplasmic reticulum-mitochondria encounter structure (ERMES) is one of the best understood membrane tethering complexes. Its discovery has yielded crucial insight into the mechanisms of intracellular lipid trafficking. Despite a wealth of data, our understanding of ERMES formation and its exact role(s) remains incomplete. Here, I endeavour to summarise our knowledge on the ERMES complex and to identify lingering gaps.
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Fratti, Rutilio A., Youngsoo Jun, Alexey J. Merz, Nathan Margolis, and William Wickner. "Interdependent assembly of specific regulatory lipids and membrane fusion proteins into the vertex ring domain of docked vacuoles." Journal of Cell Biology 167, no. 6 (December 20, 2004): 1087–98. http://dx.doi.org/10.1083/jcb.200409068.
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Membrane microdomains are assembled by lipid partitioning (e.g., rafts) or by protein–protein interactions (e.g., coated vesicles). During docking, yeast vacuoles assemble “vertex” ring-shaped microdomains around the periphery of their apposed membranes. Vertices are selectively enriched in the Rab GTPase Ypt7p, the homotypic fusion and vacuole protein sorting complex (HOPS)–VpsC Rab effector complex, SNAREs, and actin. Membrane fusion initiates at vertex microdomains. We now find that the “regulatory lipids” ergosterol, diacylglycerol and 3- and 4-phosphoinositides accumulate at vertices in a mutually interdependent manner. Regulatory lipids are also required for the vertex enrichment of SNAREs, Ypt7p, and HOPS. Conversely, SNAREs and actin regulate phosphatidylinositol 3-phosphate vertex enrichment. Though the PX domain of the SNARE Vam7p has direct affinity for only 3-phosphoinositides, all the regulatory lipids which are needed for vertex assembly affect Vam7p association with vacuoles. Thus, the assembly of the vacuole vertex ring microdomain arises from interdependent lipid and protein partitioning and binding rather than either lipid partitioning or protein interactions alone.
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Kamiya, Koki, Chika Arisaka, and Masato Suzuki. "Investigation of Fusion between Nanosized Lipid Vesicles and a Lipid Monolayer Toward Formation of Giant Lipid Vesicles with Various Kinds of Biomolecules." Micromachines 12, no. 2 (January 26, 2021): 133. http://dx.doi.org/10.3390/mi12020133.
Full textAbstract:
We determined the properties of fusion between large unilamellar vesicles (LUVs) and the lipid monolayer by measuring the fluorescence intensity of rhodamine-conjugated phospholipids in cell-sized lipid vesicles. The charge of LUVs (containing cationic lipids) and lipid droplets (containing anionic lipids) promoted lipid membrane fusion. We also investigated the formation of cell-sized lipid vesicles with asymmetric lipid distribution using this fusion method. Moreover, cell-sized asymmetric ganglioside vesicles can be generated from the planar lipid bilayer formed at the interface between the lipid droplets with/without LUVs containing ganglioside. The flip-flop dynamics of ganglioside were observed on the asymmetric ganglioside vesicles. This fusion method can be used to form asymmetric lipid vesicles with poor solubility in n-decane or lipid vesicles containing various types of membrane proteins for the development of complex artificial cell models.
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Ryan, Robert O. "Structural studies of lipoproteins and their apolipoprotein components." Biochemistry and Cell Biology 74, no. 2 (March 1, 1996): 155–64. http://dx.doi.org/10.1139/o96-016.
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Lipid transport processes via the circulatory system of animals are a vital function that utilizes highly specialized lipoprotein complexes. These complexes of protein and lipid impart solubility to otherwise insoluble lipids. The apoprotein components of lipoprotein complexes serve to stabilize the lipid components and modulate particle metabolism and function as ligands for receptor-mediated endocytosis of lipoproteins. We have used an insect (Manduca sexta) model system for studies of lipid transport. In this system, flight activity elicits a dramatic increase in the demand for glycerolipid fuel molecules by flight muscle tissue. These lipids are mobilized from a storage organ and transported through the hemolymph (blood) to the flight muscle by the lipoprotein, lipophorin. This system possesses the unique property that lipids are loaded onto pre-existing high density lipophorin through the action of a lipid transfer particle (LTP). LTP is a high molecular weight hemolymph component that facilitates net vectorial lipid transfer from fat body tissue to lipophorin. The increase in lipid content of the lipoprotein induces association of a low molecular weight amphipathic exchangeable apolipoprotein, apolipophorin III (apoLp-III). ApoLp-III is a 18 kDa protein that normally exists as a water-soluble monomeric hemolymph protein. The structural properties of apoLp-III have been investigated by X-ray crystallography. ApoLp-III from Locusta migratoria adopts a five helix bundle conformation wherein each of the amphipathic helices orients with its hydrophobic face directed toward the interior of the bundle. It has been hypothesized that lipid association requires a dramatic conformational change wherein the helix bundle opens about putative hinge domains located in the loops between helices. The data accumulated support the concept that apoLp-III is a member of the broad class of exchangeable apolipoproteins and structural information learned from this system is directly applicable to analogous proteins in higher organisms.Key words: lipid transport, apoprotein, lipoprotein, Manduca sexta, diacylglycerol.
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Overduin, Michael, and Mansoore Esmaili. "Native Nanodiscs and the Convergence of Lipidomics, Metabolomics, Interactomics and Proteomics." Applied Sciences 9, no. 6 (March 24, 2019): 1230. http://dx.doi.org/10.3390/app9061230.
Full textAbstract:
The omics disciplines remain largely distinct sciences due to the necessity of separating molecular classes for different assays. For example, water-soluble and lipid bilayer-bound proteins and metabolites are usually studied separately. Nonetheless, it is at the interface between these sciences where biology happens. That is, lipid-interacting proteins typically recognize and transduce signals and regulate the flow of metabolites in the cell. Technologies are emerging to converge the omics. It is now possible to separate intact membrane:protein assemblies (memteins) directly from intact cells or cell membranes. Such complexes mediate complete metabolon, receptor, channel, and transporter functions. The use of poly(styrene-co-maleic acid) (SMA) copolymers has allowed their separation in a single step without any exposure to synthetic detergents or artificial lipids. This is a critical development as these agents typically strip away biological lipids, signals, and metabolites from their physiologically-relevant positions on proteins. The resulting SMA lipid particles (SMALPs) represent native nanodiscs that are suitable for elucidation of structures and interactions that occur in vivo. Compatible tools for resolving the contained memteins include X-ray diffraction (XRD), cryo-electron microscopy (cryoEM), mass spectrometry (MS), and nuclear magnetic resonance (NMR) spectroscopy. Recent progress shows that memteins are more representative than naked membrane proteins devoid of natural lipid and is driving the development of next generation polymers.
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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.
Full textAbstract:
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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Bondar, Ana-Nicoleta. "Phosphatidylglyerol Lipid Binding at the Active Site of an Intramembrane Protease." Journal of Membrane Biology 253, no. 6 (November 18, 2020): 563–76. http://dx.doi.org/10.1007/s00232-020-00152-z.
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AbstractTransmembrane substrate cleavage by the small Escherichia coli rhomboid protease GlpG informs on mechanisms by which lipid interactions shape reaction coordinates of membrane-embedded enzymes. Here, I review and discuss new work on the molecular picture of protein–lipid interactions that might govern the formation of the substrate–enzyme complex in fluid lipid membranes. Negatively charged PG-type lipids are of particular interest, because they are a major component of bacterial membranes. Atomistic computer simulations indicate POPG and DOPG lipids bridge remote parts of GlpG and might pre-occupy the substrate-docking site. Inhibition of catalytic activity by PG lipids could arise from ligand-like lipid binding at the active site, which could delay or prevent substrate docking. Dynamic protein–lipid H-bond networks, water access to the active site, and fluctuations in the orientation of GlpG suggest that GlpG has lipid-coupled dynamics that could shape the energy landscape of transmembrane substrate docking. Graphic Abstract
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Maxwell, Robert J. "Determination of Total Lipid and Lipid Subclasses in Meat and Meat Products." Journal of AOAC INTERNATIONAL 70, no. 1 (January 1, 1987): 74–77. http://dx.doi.org/10.1093/jaoac/70.1.74.
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Abstract Current interest in physiological and nutritional activities of the sterol, polyunsaturated fatty acid, and polar lipid fractions of meats and other foods indicates that analytical methods for lipids should be evaluated on their ability to recover and quantitate these classes. Current methods of lipid isolation furnish an extract that is dependent on the solvent(s) used, the type of food material, the temperature of extraction, and the relative proportions of the lipid classes present. Extraction with ethers or other relatively nonpolar solvents removes principally the neutral fats and nonpolar lipids. For an approximation of the crude fat content, such extraction is often sufficient, because the nonpolar fraction generally constitutes over 90% of the total lipids present. The polar lipids include the biochemically important (ω-3) and (ω-6) polyunsaturated fatty acid classes; thus, the method of lipid extraction of food products becomes relevant for a more complete and valuable characterization of their nutritional value. The various methods of lipid determination for meat products are examined for their total recovery of these important lipid groups. A sequential extraction in conjunction with subsequent analytical methods is recommended.