scholarly journals Hepatic lipid droplets. Isolation, morphology and composition

1973 ◽  
Vol 132 (2) ◽  
pp. 323-327 ◽  
Author(s):  
Richard P. DiAugustine ◽  
Joan-Marie Schaefer ◽  
James R. Fouts
Keyword(s):  
Fatty Acids ◽  
Electron Micrographs ◽  
Lipid Droplets ◽  
Free Cholesterol ◽  
Hepatic Cell ◽  
Cholesterol Esters ◽  
Lipid Layer ◽  
Outer Coat ◽  
Mean Diameter

The floating lipid layer isolated centrifugation of rat liver was examined for composition and ultrastructure. It was chiefly composed of triglycerides and cholesterol esters plus much smaller amounts of free cholesterol, diglycerides, phospholipid and protein. No free fatty acids were detected. The triglyceride and cholesterol ester fractions consisted mostly of esters of linoleic acid, oleic acid and palmitic acid. Electron micrographs of the floating lipid layer revealed numerous spherical osmiophilic droplets having a mean diameter of 0.5–2μm with a very-thin dense outer coat. Similar structures were observed as organelles in electron micrographs of the intact liver cell. The amount of triglyceride in the layer decreased in rats starved for 72h, but pellet triglyceride (homogenate minus the floating lipid layer) was unchanged. These results suggest that the floating lipid layer is the representative in vitro of lipid-rich organelles which probably function as a depot form of hepatic-cell neutral lipid.

scholarly journals Filipin vs enzymatic localization of cholesterol in guinea pig, mink, and mallard duck testicular cells.

1994 ◽  
Vol 42 (12) ◽  
pp. 1539-1554 ◽  
Author(s):  
R M Pelletier ◽  
M L Vitale
Keyword(s):  
Guinea Pig ◽  
Lipid Droplets ◽  
Free Cholesterol ◽  
Cholesterol Oxidase ◽  
False Negative ◽  
Cholesterol Esters ◽  
Enzymatic Method ◽  
Mallard Duck ◽  
Cholesterol Levels ◽  
Testicular Cells

To test the validity of filipin cytochemistry for localization of cholesterol in testicular cells, we compared the results obtained by this technique with those obtained by a two-step enzymatic method involving cholesterol esterase and cholesterol oxidase. In all the animals models tested (guinea pig, mink, and mallard duck) the disappearance of subsurface filaments along Sertoli cell junctional membranes was accompanied by a significant increase in the number of filipin-cholesterol complexes/microns 2 in these membranes. Enzyme histochemistry allowed localization of free cholesterol in the limiting membrane of multivesicular bodies, in membranes within lysosomes, in mitochondrial membranes, and in junctional membranes, with or without subsurface filaments. The method also permitted selective visualization of cholesterol esters in lipid droplets. We conclude that filipin mapping of cholesterol induces false-negative cytochemical results. The enzymatic method is superior to filipin because it allows localization of free cholesterol in junctional membranes and of cholesterol esters in lipid droplets. This compartmentalization of the compounds may represent the basis of a system that helps to maintain constant free cholesterol levels in the testis.

scholarly journals COMPOSITION AND SYNTHESIS OF LIPIDS IN RESTING AND PHAGOCYTIZING LEUKOCYTES

1959 ◽  
Vol 110 (6) ◽  
pp. 969-980 ◽  
Author(s):  
Peter Elsbach
Keyword(s):  
Fatty Acids ◽  
Lipid Content ◽  
Polymorphonuclear Leukocytes ◽  
Dry Weight ◽  
Rabbit Serum ◽  
Gas Liquid Chromatography ◽  
Cholesterol Esters ◽  
Metabolic Stimulation ◽  
Specific Synthesis

The lipid content of rabbit polymorphonuclear leukocytes, obtained from peritoneal exudates, constituted 8.7 ± 2.9 per cent of the dry weight of these cells; 60 per cent of all lipids were phospholipids, 20 per cent triglycerides, and the remainder cholesterol and cholesterol esters and a small amount of non-esterified fatty acids (2 to 4 per cent). The composition of the fatty acids in leukocytes, as determined by gas-liquid chromatography, was slightly different from rabbit serum and red blood cells, but markedly different from the dietary fat. The synthesis, turnover, and composition of lipids in rabbit leukocytes at rest and during phagocytosis in vitro were compared. Lipid content and composition were not affected by the phagocytic process. However, active phagocytosis resulted in an increase in the rate of turnover of lipids. This stimulation of lipid metabolism was more marked in triglycerides and cholesterol esters than in phospholipids. It is suggested that the increased turnover of lipid during phagocytosis may reflect a general metabolic stimulation accompanying this process, rather than a specific synthesis of phospholipid for the production of new cell membrane.

scholarly journals Anticholesterolemic Activity of Three Vegetal Extracts (Artichoke, Caigua, and Fenugreek) and Their Unique Blend

2021 ◽  
Vol 12 ◽  
Author(s):  
Jessica Frigerio ◽  
Erik Tedesco ◽  
Federico Benetti ◽  
Violetta Insolia ◽  
Giovanna Nicotra ◽  
...  
Keyword(s):  
Bile Acids ◽  
Free Cholesterol ◽  
Complementary Therapies ◽  
Liver Lipid ◽  
Plaque Formation ◽  
Hepatic Cell ◽  
Monacolin K ◽  
Atherosclerotic Plaque Formation ◽  
The Impact

Hepatic-related diseases, in particular hyperlipidemia and hypercholesterolemia, are a thorn on the side of the national health institutes around the globe. Indeed, liver lipid and cholesterol dysregulation could lead to atherosclerotic plaque formation and cardiovascular diseases. Currently, statin administration and monacolin K consumption are the main therapies proposed to counter this alarming connection, but relevant side effects are known. To overcome this issue, safe nutraceutical formulations and/or vegetal extracts, endowed with anticholesterolemic activity, could be instrumental in hypercholesterolemia prevention and treatment. In the present work, the anticholesterolemic efficacy of three vegetal extracts used in traditional medicine (artichoke, caigua, and fenugreek), their unique blend (ACFB), and the monacolin K-containing red yeast extract (RYR), was investigated with an in vitro approach based on hepatic cell line HepG2. The impact on cholesterol of the three extracts, their blend, and RYR were investigated by determining hepatocyte total and free cholesterol and bile acids biosynthesis. According to our results, the anticholesterolemic activity of the vegetal extracts was confirmed, and a novel choleretic activity of caigua extract was evidenced. ACFB showed to be safer than RYR while showing a similar effect on total and free cholesterol and bile acids synthesis compared to it. The anticholesterolemic activity of the blend was obtained with lower vegetal extract concentrations compared with the single vegetal extract, potentially indicating an additive effect between the extracts. In conclusion, the vegetal extracts and their blend, ACFB, are safe and are endowed with anticholesterolemic activity, potentially providing complementary therapies to the statin-based ones for hyperlipidemia and hypercholesterolemia-related complications.

scholarly journals Yellow adipocytes comprise a new adipocyte sub-type present in human bone marrow

2019 ◽  
Author(s):  
Camille Attané ◽  
David Estève ◽  
Karima Chaoui ◽  
Jason Iacovoni ◽  
Jill Corre ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Stem Cells ◽  
Bone Marrow ◽  
Free Cholesterol ◽  
Cholesterol Content ◽  
White Adipocytes ◽  
Bone Marrow Adipocytes ◽  
Marrow Mesenchymal Stem Cells ◽  
Fat Depot

AbstractDuring energy demanding conditions, white adipocytes store triglycerides and release fatty acids through lipolysis. In contrast, bone marrow adipocytes (BM-Ad) increase in size during caloric restriction, suggesting this fat depot exhibits precise metabolic specificity. We found subcutaneous adipocytes (SC-Ad) and BM-Ad share morphological features, but possess distinct lipid metabolism. BM-Ad show enrichment in cholesterol-oriented metabolism that correlates with increased free cholesterol content, while proteins involved in lipolysis were downregulated. A strong down-regulation in expression of monoacylglycerol (MG) lipase was observed leading to an accumulation of major MG species and accordingly the basal and induced lipolytic responses were absent in BM-Ad. These features are not recapitulatedin vitrousing differentiated bone marrow mesenchymal stem cells. Since our data demonstrate that BM-Ad comprise a distinct class of adipocytes, we propose renaming them yellow adipocytes.

ADRENAL RESPONSES TO CORTICOTROPHIN IN THE PRESENCE OF AN INHIBITOR OF PROTEIN SYNTHESIS

1968 ◽  
Vol 58 (4) ◽  
pp. 619-629 ◽  
Author(s):  
René Maier ◽  
Matthys Staehelin
Keyword(s):  
Fatty Acids ◽  
Blood Flow ◽  
Protein Synthesis ◽  
Unsaturated Fatty Acids ◽  
Cholesterol Esters ◽  
Acth Stimulation ◽  
Inhibitor Of Protein Synthesis ◽  
Primary Action

ABSTRACT The effect of cycloheximide, an inhibitor of protein synthesis, on the response of the rat adrenal to ACTH was studied. Cycloheximide blocks corticosteroidogenesis in vivo and in vitro, but does not affect the increase in adrenal blood flow in vivo. When the corticosterone production of adrenal slices was studied after ACTH stimulation in vivo, it was found that adrenal slices from rats pre-treated with cycloheximide, secreted corticosterone just as efficiently as adrenal slices from control animals. It is concluded that cycloheximide does not block the primary action of ACTH but that it inhibits subsequent enzymatic processes taking place in the mitochondria. The hypothesis is put forward that the increase in adrenal blood flow induced by ACTH might be due to prostaglandins which could be formed from unsaturated fatty acids released by the cleavage of cholesterol esters.

327 UNSATURATED AND SATURATED NON-ESTERIFIED FATTY ACIDS DIFFERENTLY AFFECT LIPID STORAGE AND DEVELOPMENTAL COMPETENCE OF BOVINE OOCYTES

2010 ◽  
Vol 22 (1) ◽  
pp. 319
Author(s):  
H. Aardema ◽  
P. Vos ◽  
H. Knijn ◽  
B. Roelen ◽  
B. Gadella
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Palmitic Acid ◽  
Lipid Droplet ◽  
Lipid Droplets ◽  
Post Partum ◽  
Developmental Competence ◽  
Negative Effects ◽  
Esterified Fatty Acids

Fertility in high-producing dairy cows has declined over the last decades. An increased serum and follicular fluid concentration of non-esterified fatty acids (NEFAs), due to body fat mobilization in the early post partum period, has been postulated as a cause for this fertility decline. NEFA concentrations and composition may change in the environment of the oocyte and thus might affect the storage depots of esterified NEFAs in the oocyte. We exposed COCs to unsaturated (oleic acid) or saturated (palmitic acid) NEFAs during maturation and subsequently examined lipid droplets and developmental competence of the oocytes. COCs from 3-8 mm follicles of slaughterhouse ovaries were cultured in control maturation medium (TCM-199) and medium containing 100, 250, or 500 μM oleic and/or palmitic acid (10 mM fatty acid was bound to 10% BSA fatty acid free). These concentrations were based on in vivo measured NEFA concentrations in follicular fluid in the early post partum period (Leroy et al. 2005 Reproduction 130, 485-495). After 23 h of maturation, COCs were fertilized (450 per group) and cultured till the blastocyst stage, or fixed (80 per group) for lipid droplet staining with C1-BODIPY® 500/510 C12. Confocal microscopy was performed to determine lipid droplet size in (im(mean) and the number of lipid droplets per oocyte. Lipid droplet number and the log of size were analyzed using analysis of variances with condition as fixed factor. Variation was described as the standard error of the mean. Similar concentrations of palmitic or oleic acid had an opposite effect on the size of lipid droplets in oocytes. The number of lipid droplets dramatically decreased in oocytes exposed to 500 μM palmitic acid (178 ± 20), whereas the number increased after exposure to 500 μM oleic acid (554 ± 15). The number of lipid droplets of oocytes exposed to a combination of 250 μM palmitic acid and 250 μM oleic acid (421 ± 23) was comparable with the control and lower oleic and palmitic acid concentrations. Exposure of COCs to palmitic acid during maturation resulted in reduced blastocyst development in a dose-dependent manner (from 18 ± 1.4%, 13 ± 2.4% to 2.8 ± 1.3% after exposure to 500 μM) when compared to control (20 ± 2.2%) or oocytes exposed to oleic acid (from 23 ± 1.6%, 23 ± 3.3% till 28 ± 3.3%). Negative effects of palmitic acid were counteracted by simultaneous exposure to oleic acid during in vitro oocyte maturation (26 ± 5.5%). We conclude that palmitic acid elicited negative effects on early embryonic development, possibly because it induces a reduction in the number of lipid droplets. These adverse effects can be offset by oleic acid during maturation. Moreover a high oleic acid concentration increased the number and size of lipid droplets of oocytes. The regulatory pathways involved in the noted differences in lipid storage features of in vitro-matured oocytes as well as the adverse effects of palmitic acid on early embryonic development are currently under research.

scholarly journals Substrate and inhibitor specificity of the cholesterol oxidase in bovine adrenal cortex

1966 ◽  
Vol 101 (3) ◽  
pp. 819-830 ◽  
Author(s):  
PR Raggatt ◽  
MW Whitehouse
Keyword(s):  
Steroid Hormones ◽  
Adrenal Cortex ◽  
Free Cholesterol ◽  
Cholesterol Oxidase ◽  
Enoic Acid ◽  
Hydroxyl Group ◽  
Cholesterol Oxidation ◽  
Cholesterol Esters ◽  
Cholesteryl Acetate

1. Cholesteryl 3beta-sulphate is oxidized in vitro by preparations of bovine adrenal-cortex mitochondria to pregnenolone sulphate and isocaproic acid (4-methyl-pentanoic acid) without hydrolysis of the ester linkage. 2. Free cholesterol is the preferred substrate for adrenal-cortex cholesterol oxidase; the apparent K(m) for cholesteryl sulphate is 500mum and for free cholesterol 50mum under the same conditions. 3. Cholesteryl 3beta-acetate is hydrolysed by bovine adrenal-cortex mitochondria in vitro to free cholesterol, which is subsequently oxidized to more polar steroids and isocaproic acid. Evidence was obtained that other cholesterol esters behave similarly. Cholesterol esters may thus act as precursors of steroid hormones. 4. Cholest-4-en-3-one is only poorly oxidized to isocaproic acid and more polar steroids and thus is probably not a significant precursor of steroid hormones. 5. Cholesteryl esters inhibit the oxidation of cholesterol competitively (K(i) for cholesteryl phosphate 28mum, for cholesteryl sulphate 110mum, for cholesteryl acetate 65mum) but pregnenolone esters do not inhibit this system. 6. Pregnenolone and 20alpha-hydroxycholesterol (both metabolites of cholesterol in this system) inhibit the oxidation of cholesterol non-competitively. K(i) for pregnenolone is 130mum and K(i) for 20alpha-hydroxycholesterol is 17mum. 7. 25-Oxo-27-norcholesterol inhibits cholesterol oxidation non-competitively (K(i)16mum). A number of other Delta(5)-3beta-hydroxy steroids inhibit cholesterol oxidation and evidence was obtained that the 3beta-hydroxyl group was necessary for inhibitory activity. 8. Pregnenolone, 20alpha-hydroxycholesterol and 25-oxo-27-norcholesterol inhibit oxidation of cholesteryl sulphate by this system but their sulphates do not. 9. 3beta-Hydroxychol-5-enoic acid, 3alpha-hydroxy-5beta-cholanic acid and 3beta-hydroxy-22,23-bisnorchol-5-enoic acid stimulated formation of isocaproic acid from cholesterol. 10. No evidence was obtained that phosphorylation or sulphation are obligatory steps in cholesterol oxidation by adrenal-cortex mitochondria. 11. The cholesteryl 3beta-sulphate sulphatase of bovine adrenal cortex was found mostly in the microsomal fraction and was inhibited by inorganic phosphate.

scholarly journals The endoplasmic reticulum-resident protein TMEM-120/TMEM120A promotes fat storage in C. elegans and mammalian cells

2021 ◽  
Author(s):  
Yan Li ◽  
Siwei Huang ◽  
Xuesong Li ◽  
Xingyu Yang ◽  
Ningyi Xu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Endoplasmic Reticulum ◽  
Mammalian Cells ◽  
Lipid Droplets ◽  
Stimulated Raman Scattering ◽  
Transmembrane Helices ◽  
Fat Storage ◽  
Over Expression ◽  
C Elegans

The synthesis of triacylglycerol (TAG) is essential for the storage of excess fatty acids, which can subsequently be used for energy or cell growth. A series of enzymes act in the endoplasmic reticulum (ER) to synthesize TAG, prior to its transfer to lipid droplets (LDs), which are conserved organelles for fat storage. Here, we report that the deficiency of TMEM-120/TMEM120A, a protein with 6-transmembrane helices, retards TAG synthesis and LD expansion in C. elegans. GFP fusion proteins of TMEM-120, expressed at the endogenous level in live worms, were observed throughout the ER network. Using Stimulated Raman Scattering, we demonstrated the specific requirement of TMEM-120 in the storage of exogenous fatty acids in LDs. Knockdown of TMEM120A impedes adipogenesis of pre-adipocytes in vitro, while its over-expression is sufficient to promote LD expansion in mammalian cells. Our results suggest that TMEM-120/TMEM120A plays a conserved role in increasing the efficiency of TAG synthesis.

Some Structural Features of Metaphase Chromosomes of Mice and Men

1967 ◽  
Vol 25 ◽  
pp. 190-191
Author(s):  
Godfrey C. Hoskins ◽  
Betty B. Hoskins
Keyword(s):  
Electron Microscopy ◽  
Electron Micrographs ◽  
Structural Features ◽  
Metaphase Chromosomes ◽  
The Future ◽  
Of Mice And Men ◽  
Mouse Cells ◽  
Human And Mouse

Metaphase chromosomes from human and mouse cells in vitro are isolated by micrurgy, fixed, and placed on grids for electron microscopy. Interpretations of electron micrographs by current methods indicate the following structural features.Chromosomal spindle fibrils about 200Å thick form fascicles about 600Å thick, wrapped by dense spiraling fibrils (DSF) less than 100Å thick as they near the kinomere. Such a fascicle joins the future daughter kinomere of each metaphase chromatid with those of adjacent non-homologous chromatids to either side. Thus, four fascicles (SF, 1-4) attach to each metaphase kinomere (K). It is thought that fascicles extend from the kinomere poleward, fray out to let chromosomal fibrils act as traction fibrils against polar fibrils, then regroup to join the adjacent kinomere.

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