A simple method for the isolation and purification of total lipides from animal tissues.
01 May 1957-Journal of Biological Chemistry (American Society for Biochemistry and Molecular Biology)-Vol. 226, Iss: 1, pp 497-509
TL;DR: In this paper, the authors described a simplified version of the method and reported the results of a study of its application to different tissues, including the efficiency of the washing procedure in terms of the removal from tissue lipides of some non-lipide substances of special biochemical interest.
About: This article is published in Journal of Biological Chemistry.The article was published on 1957-05-01 and is currently open access. It has received 59550 citations till now. The article focuses on the topics: Triglyceride transport.
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TL;DR: It is demonstrated that metabolism by intestinal microbiota of dietary l-carnitine, a trimethylamine abundant in red meat, also produces TMAO and accelerates atherosclerosis in mice, and intestinal microbiota may contribute to the well-established link between high levels of red meat consumption and CVD risk.
Abstract: Intestinal microbiota metabolism of choline and phosphatidylcholine produces trimethylamine (TMA), which is further metabolized to a proatherogenic species, trimethylamine-N-oxide (TMAO). We demonstrate here that metabolism by intestinal microbiota of dietary L-carnitine, a trimethylamine abundant in red meat, also produces TMAO and accelerates atherosclerosis in mice. Omnivorous human subjects produced more TMAO than did vegans or vegetarians following ingestion of L-carnitine through a microbiota-dependent mechanism. The presence of specific bacterial taxa in human feces was associated with both plasma TMAO concentration and dietary status. Plasma L-carnitine levels in subjects undergoing cardiac evaluation (n = 2,595) predicted increased risks for both prevalent cardiovascular disease (CVD) and incident major adverse cardiac events (myocardial infarction, stroke or death), but only among subjects with concurrently high TMAO levels. Chronic dietary L-carnitine supplementation in mice altered cecal microbial composition, markedly enhanced synthesis of TMA and TMAO, and increased atherosclerosis, but this did not occur if intestinal microbiota was concurrently suppressed. In mice with an intact intestinal microbiota, dietary supplementation with TMAO or either carnitine or choline reduced in vivo reverse cholesterol transport. Intestinal microbiota may thus contribute to the well-established link between high levels of red meat consumption and CVD risk.
3,222 citations
TL;DR: A novel method for determining serum triglycerides, in which an enzymatic hydrolysis replaces the more commonly used saponification procedure, which is simple, rapid, and requires only 50 µl or less of sample.
Abstract: We describe a novel method for determining serum triglycerides, in which an enzymatic hydrolysis replaces the more commonly used saponification procedure. Under the conditions of the assay, the enzymatic hydrolysis can be completed in less than 10 min by the combined action of a microbial lipase and a protease. We have been able to demonstrate complete hydrolysis of triglycerides by thin-layer chromatography of the reaction products, by recovery of glycerol from sera of known triglycerides content, and by comparison of triglyceride assays on a number of sera assayed by our method vs. the AutoAnalyzer procedure. The hydrolysis is directly coupled to the enzymatic determination of glycerol, and is followed through absorbance changes at 340 nm. The assay is simple, rapid, and requires only 50 µl or less of sample. Because the enzymes used do not release glycerol from other compounds in serum, the hydrolysis can be considered specific for triglycerides.
3,113 citations
TL;DR: In this article, the authors quantified the biological sources of hepatic and plasma lipoprotein TAG in NAFLD patients, using stable isotopes for four days to label and track serum nonesterified fatty acids (NEFAs), dietary fatty acids, and those derived from the de novo lipogenesis (DNL) pathway, present in liver tissue and lipid TAG.
Abstract: Nonalcoholic fatty liver disease (NAFLD) is characterized by the accumulation of excess liver triacylglycerol (TAG), inflammation, and liver damage The goal of the present study was to directly quantify the biological sources of hepatic and plasma lipoprotein TAG in NAFLD Patients (5 male and 4 female; 44 ± 10 years of age) scheduled for a medically indicated liver biopsy were infused with and orally fed stable isotopes for 4 days to label and track serum nonesterified fatty acids (NEFAs), dietary fatty acids, and those derived from the de novo lipogenesis (DNL) pathway, present in liver tissue and lipoprotein TAG Hepatic and lipoprotein TAG fatty acids were analyzed by gas chromatography/mass spectrometry NAFLD patients were obese, with fasting hypertriglyceridemia and hyperinsulinemia Of the TAG accounted for in liver, 590% ± 99% of TAG arose from NEFAs; 261% ± 67%, from DNL; and 149% ± 70%, from the diet The pattern of labeling in VLDL was similar to that in liver, and throughout the 4 days of labeling, the liver demonstrated reciprocal use of adipose and dietary fatty acids DNL was elevated in the fasting state and demonstrated no diurnal variation These quantitative metabolic data document that both elevated peripheral fatty acids and DNL contribute to the accumulation of hepatic and lipoprotein fat in NAFLD
2,870 citations
TL;DR: An improved method for extracting the lipids from tissues consists of the use of hexane:isopropanol, followed by a wash of the extract with aqueous sodium sulfate to remove nonlipid contaminants.
2,400 citations
TL;DR: This one-step direct transesterification procedure carried out in methanol-benzene 4:1 with acetyl chloride is superior to currently used methods not onlyBecause of its simplicity and speed, but also because of its added precision.
2,315 citations
References
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TL;DR: A simple method is described for the preparation of extracts of total pure lipides from brain tissue by homogenizing the tissue with a chloroform-methanol mixture and washing free of non-lipide contaminants.
1,203 citations
707 citations
TL;DR: The values for cerebrosides found in the current literature include gangliosides, and other investigators (JOHNSON, MCNABB, and ROSSITER, 1950; CUMINGS, 1953; BLACKWOOD and CUMings, 1954) have neglected the ganglariosides.
Abstract: THE extensive research work in the physiological and pathological processes in which lipids are involved has increased the necessity for accurate micromethods for their quantitative estimation. BRANTE (1949) reviewed modern micromethods for the determination of the lipids in nervous tissue, and made a thorough investigation of the various factors which may influence them. Like most other investigators, BRANTE determined the cerebroside content only by estimating the reducing substances in a lipid extract before and after hydrolysis. From the important work of KLENK and collaborators (KLENK, 1941, 1942; KLENK and LANGERBEINS, 1941 ; SCHUWIRTH. 1940) we know that cerebrosides are not the only lipids containing carbohydrates in the central nervous system. They have isolated gangliosides from the brain and determined their amount in different nervous tissues. Besides these two glycolipids, a third has been described by ARSOVE, FOLCH, and MEATH (1951a). They named the new lipid strandin, but my preparations like DAWN'S (1952), showed that strandin consisted of gangliosides in a different physico-chemical state contaminated with low-molecular substances and mucopolysaccharides. CHATAGNON and CHATAGNON (1953, 1954) have suggested that sphingomyelin is also a part of the complex. BRANTE (1949) discussed the interference of gangliosides on the cerebroside values, and we (BRANTE and SVENNERHOLM, 1949, 1951) determined both total glycolipids and gangliosides in some foetuses. Other investigators (JOHNSON, MCNABB, and ROSSITER, 1950; CUMINGS, 1953; BLACKWOOD and CUMINGS, 1954) have neglected the gangliosides. Therefore the values for cerebrosides found in the current literature include gangliosides. EDGAR (1955) who has thoroughly discussed the problem, used the term glyco-sphingosides instead of cerebrosides. He has also made some estimations of both gangliosides and cerebrosides. Consequently, the carbohydrates in a lipid extract are derived from at least two lipid sources. But lipid extracts are contaminated to some extent with low-molecular substances, partly of carbohydrate nature. It is impossible to remove them completely by the methods generally used, i.e., precipitation of the lipids before extraction or re-extraction of a primary lipid extract. Generally, the error introduced by the contaminants is negligible i n the determination of glycolipids in adult nervous tissue, but this is not so in foetal tissue, where the amount of glycolipids is low and that of the contaminants is both relatively and absolutely higher. FOLCH, ASCOLI, LEES. MEATH, and LEBARON (1951b), however, succeeded in removing these substanccs by partition dialysis. By this procedure the gangliosides too are separated from the other lipids. It therefore appeared that it might be possible to use this method to separate cerebrosides from other substances containing carbohydrates.
533 citations
TL;DR: The isolation from brain tissue of a substance to which the name of strandin has been given for descriptive purposes is reported, which has the property of forming long strands that show perfect orientation under polarized light.
253 citations
227 citations