Chemical composition of subcellular particles from cultured cells of human tissue

Chemical composition of subcellular components of HeLa, KB, human heart and liver tissue-culture cell lines have been studied. The concentration of RNA, protein and phospholipid (μg/μg of DNA) of total subcellular particles was similar for all four cell lines studied. The greatest RNA concentration and lowest protein concentration is found in the microsomes as compared to the other subcellular fractions of HeLa and KB cells. The lipid P/Protein N ratio of mitochondria was greater than the other subcellular fractions from tissue-culture cell lines studied. Phosphatidyl choline and phosphatidyl ethanolamine are the major phospholipids with the former more predominant in all of the subcellular fractions of tissue-culture cells studied. Phosphatidyl inositol, phosphatidyl serine, sphingomyelin and polyglycerol phosphatide were shown to be present. Phosphatidyl choline composition (per cent of total lipid-P) is greatest in the microsomes when compared with the other subcellular fractions obtained from all of the cell lines studied except the nuclear fraction of human liver cells. Correspondingly, the mitochondrial fraction for all of the tissue culture cell lines contains the greatest composition of phosphatidyl ethanolamine except for the human liver and heart cells. The mitochondrial fraction contains the lowest amount of phosphatidyl inositol. Polyglycerol phosphatide is mainly present in the mitochondrial fraction of the tissue-culture cells. Part of a thesis submitted to the Graduate School of the University of North Dakota in partial fulfillment for the degree of Doctor of Philosophy.     

Biosynthesis of phospholipids in subcellular particles from cultured cells of human tissue

A time study of the incorporation of³²P_i into the phospholipids of HeLa, KB, human heart, and liver tissue-culture cell lines has been carried out. The incorporation of³²P_i at various time-intervals into the phospholipids of nuclei, mitochondria, and microsomes of HeLa and KB cells was investigated. The labeling of the isotope into the phospholipids was divided into three groups. The first had two components: phosphatidyl inositol and polyglycerol phosphatides, which showed the greatest incorporation of the isotope as demonstrated in the specific activity values and the percentage of total radioactivity after 15 to 30 minutes of incubation. A second group was composed of the major phospholipids of all tissue-culture cell lines studied, phosphatidyl choline, and phosphatidyl ethanolamine. At first, there was a delayed labeling of these phospholipids; however, after one hour of incubation, a rapid increase was shown in the incorporation of³²P_i. A third group of lipids containing sphingomyelin and phosphatidyl serine demonstrated low specific activity values. The phospholipids of the subcellular fractions, nuclei, mitochondria, and microsomes, had a high degree of incorporation of the isotope into the individual phospholipids and probably represented an active process in the membranes of these cellular units or a renewal of the biological membrane structures. Part of a thesis submitted to the Graduate School of the University of North Dakota in partial fulfillment for the degree of Doctor of Philosophy.     

Bitterness of Lipids

We have been able to demonstrate, that the hydrophobicity of the amino acid side chains is responsible for the bitterness of a peptide. Now we investigated lipids (and carbohydrates) in the following classes: Monoglycerides, diglycerides, phosphatides, lysophosphatides, monohydroxy fatty acids, dihydroxy fatty acids, trihydroxy fatty acids, monosaccharides, disaccharides. It was found that for lipids and carbohydrates the ratio from the number of the C-atoms of a molecule to the number of the hydroxyl groups called the R-values, gave a good indication as to whether the lipid or carbohydrate was sweet, bitter or non-bitter. For sweet compounds we found R = 1.00 - 1.99, for bitter compounds we found R =2.00 - 6.99, and for non-bitter compounds we found a value of R higher than 7.00. These results confirm our earlier assumption, that like in the case of peptides, the bitterness of lipids and carbohydrates is caused by a certain range of the hydrophobicity.     

Lipids of dermatophytes

This investigation deals with phosphatides and fatty acid content ofEpidermophyton floccosum, Microsporum cookie andTrichophyton mentagrophytes during different phases of growth. Total phosphatide content of these dermatophytes decreased with age, which was reflected in constituent major phosphatides. The zwitterionic and anionic phospholipids tended to maintain a constant ratio. Short chain fatty acids increased significantly with age inE. floccosum whereas these fatty acids represented a minor fraction of the total fatty acids inM. cookie andT. mentagrophytes. The ratio of saturated to unsaturated fatty acids increased 4-fold during growth inE. floccosum, whereas this increase was marginal inM. cookie. This ratio decreased inT. mentagrophytes.     

Photoswitchable Lipids

Photoswitchable lipids are emerging tools for the precise manipulation and study of lipid function. They can modulate many aspects of membrane biophysics, including permeability, fluidity, lipid mobility and domain formation. They are also very useful in lipid physiology and enable optical control of a wide array of lipid receptors, such as ion channels, G protein-coupled receptors, nuclear hormone receptors, and enzymes that translocate to membranes. Enzymes involved in lipid metabolism often process them in a light-dependent fashion. Photoswitchable lipids complement other functionalized lipids widely used in lipid chemical biology, including isotope-labeled lipids (lipidomics), fluorescent lipids (imaging), bifunctional lipids (lipid–protein crosslinking), photocaged lipids (photopharmacology), and other labeled variants.     

Lipids of human myocardium

The major lipid classes, including some phospholipids, and their fatty acid profiles have been measured in portions of left ventricular muscle and psoas muscle obtained at autopsy. Atrial appendages and ventricular muscle removed during cardiac surgery were examined also. The proportions of the individual phospholipids were the same in all the muscles, having an excess of phosphatidyl ethanolamine and phosphatidyl serine compared with the serum. Their fatty acid profiles resembled those obtained from other locations. The triglyceride content of the myocardium was relatively constant (except in the atrial appendage) but did rise slightly with increasing obesity. The free fatty acid concentration in the myocardium was relatively high and had a variable fatty acid profile.     

Lipids of bovine thyroid

The lipid composition of the freshly slaughtered bovine thyroid tissue has been investigated. The phospholipid patterns of microsomal and mitochondrial fractions obtained from homogenates of bovine thyroids have also been determined. They resemble the phospholipid composition of the corresponding subcellular fractions from other tissues. The fatty acid composition of the various phospholipid species of these subcellular components have also been estimated by gas liquid chromatography. These analyses reveal that the fatty acids are not particularly characteristic of the subcellular organelle but tend to be characteristic of the lipid species. There is a high percentage of nervonic acid (C24∶1) in all the subcellular phospholipid species examined.     

Fatty acid composition of subcellular particles from sheep platelets and topological distribution of phosphatidylethanolamine fatty acids in the plasma membrane

The fatty acid composition of individual phospholipids in subcellular fractions of sheep platelets and the asymmetrical distribution of phosphatidylethanolamine (PE) fatty acyl chains across the plasma membrane were examined. The main fatty acids of total lipid extracts were oleic (18∶1; 32–41%), linoleic (18∶2, 10–17%), stearic (18∶0; 13–15%), palmitic (16∶0; 11–15%) and arachidonic (20∶4; 8–12%) acids, with a saturated/unsaturated ratio of about 0.4. Each phospholipid class had a distinct fatty acid pattern. Sphingomyelin (SM) showed the highest degree of saturation (50%), with large proportions of behenic (22∶0), 18∶0 and 16∶0 acids. The main fatty acid in PE, phosphatidylserine (PS) and phosphatidylcholine (PC) was 18∶1n−9. Our findings suggest that fatty acids are asymmetrically distributed between thecholineversus the non-choline phospholipids, and also between plasma membranes and intracellular membranes. The transbilayer distribution of PE fatty acids in plasma membranes from non-stimulated sheep platelets was investigated using trinitrobenzenesulfonic acid (TNBS). A significant degree of asymmetry was found, which is a new observation in a non-polar cell. The PE molecules from the inner monolayer contained higher amounts of 18∶2 and significantly less 18∶1 and 20∶5 than those found in the outer monolayer, although no major differences were detected in the transbilayer distribution of total unsaturatedversus saturated PE acyl chains.     

化妆品中的脂质体（英）

化妆品配方师可从许多来源中选择各种油脂,但最终要由质量、价格和性能来评价。脂质体为化妆品配方提供了显著的性能,它使皮肤润滑、柔和、富有弹性,具有封闭性,在皮肤上能产生一层薄膜以防止皮肤中水份散失。另外,它的清洗、乳化、光泽、附着性和润滑性都拓宽了脂质体及其衍生物的应用范围。介绍了一种由遗传工程开发并已商业化生产的富含月桂酸酯的月桂酸Ｃａｎｏｌａ油,它在温和及泡沫方面有肯定的优势。油脂的纯度对化妆品配方非常重要,化妆品乳液的稳定性取决于脂质体的纯度。还介绍了化妆品组分评述规划的作用。     

Lipids in cheese

Lipids are present in cheese at levels above 20% and are analyzed by several techniques. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) are used to examine the microstructure, gas chromatography is employed to look at fatty acid composition, and differential scanning calorimetry is utilized to examine the melting profile. Differences resulting from storage, organic feeding regimen, substitution of milk from a different species, and homogenization may be determined.     

Lipids in soil

As much as 20% of soil humus occurs in the form of lipids. High values are characteristic of Podzol soils and highmoor peats. Lipids of the following types are known to be present: paraffin hydrocarbons, phospholipids, fats, waxes, fatty acids, and terpenoids. A long list of compounds have been reported; the identification of many of them require confirmation using modern analytical techniques. Some of the lipids known to occur in soil have phytotoxic properties; these may have a depressing effect on seed germination and on root and shoot growth. Waxes and similar materials may be responsible for the difficultly wettable condition of certain sands.     

Lipids and biopackaging

Packaging is important to preserve food quality. It is a barrier to water vapor, gas, aroma, and solute migration between the food and the environment. With the recent increase in ecological consciousness, research has turned toward finding biodegradable materials. The different kinds of biopackaging are discussed with special focus on edible films. The aim of this review is to focus on the influence of lipids used in edible films, mainly for their efficiency as water-vapor barriers. The structure, degree of saturation, chainlength, physical state, shape and dimension of crystals, and distribution of lipids into the film influence the functional properties of the film. In general, the performance of edible films is lower than that of synthetic films, but their main advantage is to be easily, fully, and rapidly biodegradable.     

Lipids of some thermophilic fungi

Total lipid content in the thermophilic fungi—Thermoascus aurantiacus, Humicola lanuginosa, Malbranchea pulchella var.sulfurea, andAbsidia ramosa—varied from 5.3 to 19.1% of mycelial dry weight. The neutral and polar lipid fractions accounted for 56.4 to 80.2% and 19.8 to 43.6%, respectively. All the fungi contained monoglycerides, diglycerides, triglycerides, free fatty acids, and sterols in variable amounts. Sterol ester was detected only inA. ramosa. Phosphatide composition was: phosphatidyl choline (15.9–47%), phosphatidyl ethanolamine (23.4–67%), phosphatidyl serine (9.3–17.6%), and phosphatidyl inositol (1.9–11.9%). Diphosphatidyl glycerol occurred in considerable quantity only inH. lanuginosa andM. pulchella var.sulfurea. Phosphatidic acid, detected as a minor component only inM. pulchella var.sulfurea andA. ramosa, does not appear to be a characteristic phosphatide of thermophilic fungi as suggested earlier. The 16∶0, 16∶1, 18∶0, 18∶1, and 18∶2 acids were the main fatty acid components. In addition,A. ramosa contained 18∶3 acid. Total lipids contained an average of 0.93 double bonds per mole of fatty acids, and neutral lipids tend to be more unsaturated than phospholipids.     

Lipids of seven cereal grains

Grain samples of representative varieties of barley, corn, oats, rye, sorghum, triticale, and wheat grown commercially in the north central US were analyzed. Chemical constituents of the varieties studied are presented to provide an overview of their characteristics. Lipids of the milled grain samples were solvent extracted, classified by silicic acid column chromatography, and separated by thin layer chromatography. Fatty acid composition of the total lipid was determined by gas liquid chromatography and the fatty acid content was determined by saponification and extraction. Total lipid content of the grains ranged from 2.3% for ‘Polk’ wheat to 6.6% for ‘Chief’ oats. Lipid composition varied considerably. The row crops, corn and sorghum, have a high neutral lipid and low glycolipid content. The small grain varieties have a more balanced distribution among neutral lipids, glycolipids, and phospholipids. Fatty acid composition of the total lipid was similar for all grains. Minor qualitative differences were noted among the lipid classes of the 7 cereals.     

Lipids of the earthwormLumbricus terrestris

The lipid composition of the earthwormLumbricus terrestris has been reexamined under conditions intended to avoid enzymatic and chemical alterations during storage, extraction, and fractionation procedures. The simple lipids included aliphatic hydrocarbons, steryl esters, glycerides, and at least nine different sterols, all though to be derived from the diet. Free fatty acids, previously considered to be major components of worm lipids, comprised only 0.3% of the total lipid weight. Phospholipids included (in order of relative abundance) phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol, as well as sphingomyelin. Glycolipids included cerebrosides and sulfatides containing both glucose and galactose, and gangliosides containing glucosamine and sialic acid. The fatty acid compositions of these lipid classes appeared to be a mixture of what are considered typical plant, bacterial, and animal acids. Several fatty acids found in the worms, includingcis-vaccenic and eicosapentaenoic acids, were essentially absent from the dietary components, and it is concluded that these acids were synthesized in the worms. The earthworm derives much of its lipid adventitiously, but exerts at least some control over its tissue lipid composition.