Showing papers in "Lipids in 1971"
TL;DR: Experiments indicated that unsaturated fats enhance the yield of adenocarcinomas more than saturated fats, and the possible relevance of these findings to the incidence of breast cancer in humans is discussed.
Abstract: Female Sprague-Dawley rats on semisynthetic diets containing 10% and 20% by weight of corn oil developed more mammary adenocarcinomas after treatment with a single oral dose of 7,12-dimethylbenz(α)anthracene than similar rats on diets containing only 0.5% or 5% corn oil. Experiments with 10 different fats and oils fed at the 20% level indicated that unsaturated fats enhance the yield of adenocarcinomas more than saturated fats. Fibroadenomas and adenomas were also found in small numbers in all dietary groups but the yield did not seem to be influenced by level or type of dietary fat. The possible relevance of these findings to the incidence of breast cancer in humans is discussed.
278 citations
TL;DR: Gas and thin layer chromatography and mass spectroscopy in particular, have been used to resolve some of the confusion concerning the sterol composition of algae.
Abstract: Available analytical techniques are now sufficient for the separation and identification of sterols from complex mixtures in plants. Gas and thin layer chromatography and mass spectroscopy in particular, have been used to resolve some of the confusion concerning the sterol composition of algae. Red algae (Rhodophyta) contain primarily cholesterol, although several species contain large amounts of desmosterol, and one species contains primarily 22-dehydrocholesterol. Only a few Rhodophyta contain traces of C-28 and C-29 sterols. Fucosterol is the dominant sterol of brown algae (Phaeophyta), apparently the major sterol of every species examined. Most Phaeophyta also contain traces of cholesterol and biosynthetic precursors of fucosterol. The sterols of green algae (Chlorophyta) are much more varied and complex than those of other groups of algae. Whereas the Phaeophyta and Rhodophyta contain one primary sterol, many of the Chlorophyta contain a complex mixture of sterols such as occurs in higher plants. The Chlorophyta contain such sterols as chondrillasterol, poriferasterol, 28-isofucosterol, ergosterol, cholesterol and others. Sterol composition may be of value in the systematics of plants such as the Chlorophyta. Recently (for the first time) complex mixtures of sterols have been isolated in very small amounts in the blue-green algae (Cyanophyta). Available data on the sterols of other groups of algae are insufficient for making useful comparisons.
253 citations
TL;DR: The aerobic desaturation of unsaturated fatty acids in the microsomes has been systematically explored and some of the relevant experimental works have been assembled.
Abstract: The aerobic desaturation of unsaturated fatty acids in the microsomes has been systematically explored and some of the relevant experimental works have been assembled. The contribution of the microsomal electron transport chain and lipoproteic structure of the microsomes is analyzed. Evidences of linoleyl-CoA and α-linolenyl-CoA being desaturated by the same enzyme are presented. The linoleic acid desaturation is shown to be different in different tissues and to decrease with aging. The effect of competitive reactions with acids of the same or different series, the competition of desaturation and transesterification, and dietary and hormonal contributions to unsaturated fatty acids desaturation are summarized. Alltrans linoleic acid and elaidic acid were not desaturated in our experimental conditions by rat liver microsomes. From the bulk of data collected, a hypothetical model of 6-olefinase is drawn. The main features of the model are: The existence of both binding and desaturating sites; the binding of acyl-CoA and enzyme through hydrophobic forces of the Van der Waals type and weak polar attractions due to double bonds; the orienting binding characteristics of double bond proximate to the place where olefination will take place; and the importance of enzyme conformation that requires that the orienting double bond must have acis structure.
216 citations
TL;DR: In this paper, it was shown that methanolysis precedes the saponification of esters in methanolic solutions of sodium hydroxide, which greatly favors methoxide formation even in the presence of rather considerable amounts of water.
Abstract: Evidence is offered to support the contention that methanolysis precedes the saponification of esters in methanolic solutions of sodium hydroxide. This results from the hydroxide-alkoxide equilibrium which greatly favors methoxide formation even in the presence of rather considerable amounts of water. Saponification-reesterification methods of methyl ester formation are shown to be actually extensions of methanolysis procedures. A simplified method is proposed for the preparation of fatty acid methyl esters.
207 citations
TL;DR: Liver microsomes and mitochondria and heart sarcosomes from rats fed diets with varying α-tocopherol concentrations and lipid contents were peroxidized over a 6 hr time period and fluorescent molecular damage represented by that accumulated in human heart age pigment by 50 years of age was calculated.
Abstract: Liver microsomes and mitochondria and heart sarcosomes from rats fed diets with varying α-tocopherol concentrations and lipid contents were peroxidized over a 6 hr time period. Lipid peroxidation was measured by absorption of oxygen, production of thiobarbituric acid (TBA) reactants and by development of fluorescence. The spectral characteristics of the fluorescent compounds were the same for all peroxidizing systems; the excitation maximum was 360 nm and the emission maximum was 430 nm. As time of peroxidation increased, uptake of oxygen and production of fluorescent compounds increased. These two parameters as well as production of TBA reactants were dependent upon dietary antioxidant and all three had an inverse relationship with the amount of dietary α-tocopherol. The relationship between absorption of oxygen and development of fluorescent compounds was also dependent upon dietary polyunsaturated fats (PUFA). Subcellular particles from animals fed higher levels of PUFA produced more fluorescent products per mole of oxygen absorbed than did those from animals on a diet with lower PUFA content. TBA reacting products increased with time during the initial phase of peroxidation: in the microsomal systems their production stabilized or decreased by 4–6 hr of peroxidation. Using the synthetic 1-amino-3-iminopropene derivative of glycine as standard for quantitation of fluorescence, the molar ratios of oxygen absorbed per fluorescent compound produced were calculated. This ratio for subcellular particles isolated from rats fed diets with PUFA ratios similar to those in the average American human diet was 393∶1. The fluorescent compounds had the same spectral characteristics as the lipofuscin pigment that accumulates in animal tissues as a function of age, oxidative stress or antioxidant deficiency. The fluorescent molecular damage represented by that accumulated in human heart age pigment by 50 years of age was calculated to have been caused by approximately 0.6 μmole of free radicals per gram of heart tissue.
199 citations
TL;DR: Stereospecific analysis determines how the fatty acids of triglycerides are distributed over the three different positions of the glycerol as discussed by the authors, which is the special problem is the differentiation of position I-1 and L-3.
Abstract: Stereospecific analysis determines how the fatty acids of triglycerides are distributed over the three different positions of the glycerol. The special problem is the differentiation of position I-1 and L-3 of glycerol. In the presently known methods, triglycerides are first degraded to mixtures of diglycerides, either by the action of a lipase or by degradation with a Grignard reagent. The isomeric diglycerides are then resolved with the help of a stereospecific enzyme, either a diglyceride kinase or (after conversion of the diglycerides to phospholipids) a phospholipase. It is then possible to analyze or calculate the fatty acid composition for each position on the glycerol. The key to a successful stereospecific analysis is the preparation of a representative diglyceride mixture by a truly random degradation of the triglyceride. The Grignard degradation is the most reliable method, but it is not always applicable, and it is accompanied by some isomerization of glycerides. There is room for improvement in the method. Analyse of natural fats have shown most of them to be asymmetric, i.e., the composition of fatty acids in position 1 differs markedly from that of position 3. Several rules of fatty acid distribution have become apparent.
128 citations
TL;DR: The isolation and identification of cholesterol α-oxide, coprostanol, β-sitosterol, cholest-4-en-3-one and cholesta-4, 6-dien- 3-one from human serum are reported.
Abstract: The isolation and identification of cholesterol α-oxide, coprostanol, β-sitosterol, cholest-4-en-3-one and cholesta-4, 6-dien-3-one from human serum are reported. Compounds were isolated by thin layer chromatography and were identified by gas liquid chromatography and gas chromatography-mass spectrometry (GC-MS). Data for standard sterols are also reported. The possible origins of these minor components and the significance of their presence are discussed.
114 citations
TL;DR: The data indicate that the luteolytic action of PGF2α is directly on the corpus luteum and this action appears to be mediated by a neutralization of prolactin activity, induced by P GF2α depressed ovarian cholesterol ester turnover and the availability of cholesterol for conversion to progesterone.
Abstract: The regulation of cholesterol ester synthetase and cholesterol esterase by prostaglandins and gonadotrophins in luteinized ovaries of the rat was studied. Prostaglandin F2α (PGF2α) depressed ovarian cholesterol esters by 75% (p<.025) within 48 hr. Hypophysectomy (APX) produced a similar effect; prolactin administration to this group maintained cholesterol esters at a higher level than in the APX group but the trophic effect of prolactin was abolished by simultaneous PGF2α treatment. Progesterone output in incubated ovarian slices was reduced 50% by PGF2α treatment in vivo (p<.005), an effect similar to that produced by APX. Prolactin administration in vivo maintained the ability of the incubated tissue to synthesize progesterone at an elevated rate in APX rats but simultaneous PGF2α treatment abolished this action of prolactin. Cholesterol ester synthetase activity was severely depressed (p<.005) by PGF2α treatment to animals with intact pituitaries, a decrease similar to that produced by APX alone. The effect of APX on synthetase activity was reversed by prolactin treatment but not when PGF2α was administered with prolactin. Esterase activity, also maintained by prolactin in APX animals (p<.005), was not affected to the same extent by PGF2α although a decrease in activity was produced in both the intact and the APX+ prolactin group by PGF2α (p<.10). However simultaneous administration of luteinizing hormone (LH) reversed the effect of PGF2α in the APX+ prolactin +PGF2α group on esterase activity. These data indicate that the luteolytic action of PGF2α is directly on the corpus luteum and this action appears to be mediated by a neutralization of prolactin activity. The loss in synthetase activity and to some extent in esterase activity, induced by PGF2α depressed ovarian cholesterol ester turnover and the availability of cholesterol for conversion to progesterone.
97 citations
TL;DR: The recent literature on the tocopherols in natural, processed and prepared foods is summarized and the evidence suggests that the identities of the specific forms are characteristic of the source.
Abstract: Methods are now available for the determination of all the specific tocopherol forms found in nature. Although the greatest interest centers on alpha-tocopherol, much information has been gathered on the amounts of individual tocopherols in foods and fats contributing to the human diet. This paper summarizes and discusses the recent literature on the tocopherols in natural, processed and prepared foods. Alpha-tocopherol, although the most widely distributed, is in many instances not the predominant form. In a number of important tocopherol sources, e.g., soybean oil, much larger amounts of gamma-tocopherol are found. The levels of tocopherols are variable, but the evidence suggests that the identities of the specific forms are characteristic of the source. In cereal grains the further observation may be made that the related tocol-tocotrienol pairs tend to be found together. Processing and preparation almost invariably reduce the tocopherol content, sometimes to insignificant levels.
90 citations
TL;DR: Experimental data indicate that enzymic electron transport associated with TPNH oxidation by the microsomal membrane involves free radical functions, which apparently can promote extensive peroxidative alterations of phospholipids that result in structural changes in the membrane unless adequate α-tocopherol is present in this organelle.
Abstract: Events accompanying electron transport in the membrane fraction of liver and other tissues have led us to propose a specific function for α-tocopherol based on a sequence of biochemical changes we observed to occur in these membranes and on pertinent information from other laboratories. The activity of a membrane-bound enzyme system (TPNH oxidase) which involves transport of electrons from substrate to oxygen, has been shown to promote simultaneous formation of peroxide functions on the β position polyunsaturated fatty acids (PUFA) of phospholipids in the membrane. The phospholipid peroxides then undergo a chain cleavage reaction producing phospholipids containing a variety of carbonyl moieties in the β position. The process results in marked alteration of the membrane structure. During the overall reaction α-tocopherol present in the membrane is converted to a compound more polar than tocopheryl quinone and the conversion is dependent on the same enzymic factors promoting the phospholipid alterations. The membrane alteration process is enhanced in microsomes from animals fed diets containing relatively high levels of PUFA or diets low in α-tocopherol, and is diminished by low levels of dietary PUFA or relatively high levels of α-tocopherol. The experimental data indicate that enzymic electron transport associated with TPNH oxidation by the microsomal membrane involves free radical functions. The latter apparently can promote extensive peroxidative alterations of phospholipids that result in structural changes in the membrane unless adequate α-tocopherol is present in this organelle. This system appears to be part of the microsomal drug metabolizing system.
90 citations
TL;DR: The author advances the hypothesis that sterols have similar functions in plants by suggesting sterols in animals may act as precursors of other steroids, as hormones and as membrane components.
Abstract: Sterols have at least three functions in animals: they may act as precursors of other steroids, as hormones and as membrane components. The author advances the hypothesis that sterols have similar functions in plants.
TL;DR: In this paper, a cucumber homogenates were incubated with 14C-linolenic and 14Clinoleic acid and the radioactivity of 0.3% was recovered in the fraction of flavor active aldehydes.
Abstract: Cucumber homogenates were incubated with14C-linolenic and14C-linoleic acid. Of the radioactivity, 0.3% was recovered in the fraction of flavor active aldehydes. The distribution of the specific racioactivity indicated that propanal,trans-2-hexenal andtrans-2,cis-6-nonadienal are related to 18∶3 and hexanal andtrans-2-nonenal to 18∶2. A pathway for the development of these compounds is discussed.
TL;DR: A simple, direct method for quantititive analyses of mixtures was developed and was found applicable for mixtures of unsaturated wax esters after reduction with tetradeuterio hydrazine.
Abstract: Several ions in the mass spectra of wax esters were related to the molecular structures Assigned structures of ions were confirmed by deuterium labeling A simple, direct method for quantititive analyses of mixtures was developed The method involved a comparison of sets of three ions, RCO2H(+), RCO2H2 (+) and [R'-1](+) from all compounds in the mixture The method was found applicable for mixtures of unsaturated wax esters after reduction with tetradeuterio hydrazine
TL;DR: The amount of myelin isolated from the central nervous system was decreased in nutritionally deprived animals but there was little change in its chemical composition or intereference in the normal chemical maturation of the membrane.
Abstract: Newborn rats were segregated into litters of 6 and 22 pups. Undernourished groups were maintained for 21 and 53 days at which time a portion of each group was sacrificed and the remainder refed until 121 days. The amount of myelin isolated from the central nervous system was decreased in nutritionally deprived animals but there was little change in its chemical composition or intereference in the normal chemical maturation of the membrane. The only consistent change was a reduction in phosphatidyl ethanolamine plasmalogen. This deficit tended to be corrected by nutritional rehabilitation and was most complete in those animals refed ad lib. diets for the longest time periods prior to sacrifice. The relatively normal chemical composition of myelin obtained from undernourished animals differs from changes described in myelin membranes isolated from patients with destructive or degenerative diseases of the nervous system. This seems to be further evidence that the reduction in myelination in undernutrition is a result of decreased synthesis of the membrane.
TL;DR: Electron microscopy of the isolated oil droplets and the seed tissue in vivo revealed particulate containing vacuole-like inclusions which, it is suggested, are the site of lipid synthesis and which form the original locus of the droplet.
Abstract: Fat droplets isolated from maturing castor bean seeds contain high concentrations of fatty acid synthetase and triglyceride synthesizing enzymes. These activities are not due to contamination by other organelles and account for at least 80% of the total lipid synthesis. Electron microscopy of the isolated oil droplets and the seed tissue in vivo revealed particulate containing vacuole-like inclusions which, it is suggested, are the site of lipid synthesis and which form the original locus of the droplet.
TL;DR: Investigation of the two sources of lipid phosphorus in milk revealed that they involve the same individual phospholipids, in essentially the same proportions with similar fatty acid compositions, rendering the MFGM an unlikely origin of the skim milk lipoprotein.
Abstract: Forty-two per cent of the lipid phosphorus in milk was found in skim milk lipoprotein; the other 58% occurs in the milk fat globule membrane (MFGM). Investigation of these two sources of lipid phosphorus revealed that they involve the same individual phospholipids, in essentially the same proportions with similar fatty acid compositions. Both contain sphingomyelin and cerebrosides in levels characteristic of those found in plasma membranes. Other points of resemblance between MFGM and skim milk lipoprotein, have been shown previously. Infusion of (14C) palmitate into the mammary gland of a lactating goat produced more extensive labeling of all the phospholipid classes in the skim milk lipoproteins than in those in the MFGM during the following 24 hr. When (14C) palmitate was infused into the jugular vein of a lactating goat, a precusor-product-type relationship was observed between specific activities of the skim milk and MFGM polar lipids. These results render the MFGM an unlikely origin of the skim milk lipoprotein. Other possible sources of this latter lipoprotein are Golgi vesicle membranes or plasma membrane of the lactating cell.
TL;DR: The lipid components of four strains of Agricus bisporus (Lange) Sing, the cultivated mushroom, were analyzed as discussed by the authors, and a method for obtaining mycelium free of compost was developed.
Abstract: The lipid components of four strains ofAgricus bisporus (Lange) Sing., the cultivated mushroom, were analyzed. Both sporophore and mycelial samples were obtained from beds in normal production. A method for obtaining mycelium free of compost was developed. Neutral lipids were separated from polar lipids by silicic acid column chromatography. Each fraction was separated by thin layer chromatography. Fatty acid methyl esters were analyzed by gas liquid chromatography and mass spectrometry. Sporophore extracts contained free sterol, free fatty acid, triglycerides, phosphatidyl choline and phosphatidyl ethanolamine. High amounts of linoleic acid were found in both neutral and polar lipid fractions. Mycelial extracts contained free fatty acids, triglycerides, phosphatidylcholine and phosphatidyl ethanolamine. No free sterol could be detected. Linoleic acid was also present in large amounts.
TL;DR: Brain lipid analyses, carried out at various time intervals in EFA deficient animals, indicate that brain weights are already reduced in 10-day-old deficient rats, that brain phospholipids decrease, especially in the males after three months, and that fatty acid distribution changes begin rather early.
Abstract: Essential fatty acid (EFA) deficiency modifies several biological parameters, i.e., growth, metabolic rate and water balance and induces functional changes in liver, kidney and lung tissues. The brain fatty acid changes reported in the literature are generally smaller than those observed in other tissues. However, EFA deficiency initiated in rats prior to birth and continued for a prolonged period of time results in decreased brain weight, brain lipid and phospholipid content and in considerable changes in polyunsaturated fatty acid distribution, especially in the ethanolamine phosphoglyceride fraction. The unsaturation level of this phospholipid is maintained at a constant level in spite of the fatty acid distribution changes. Brain lipid analyses, carried out at various time intervals in EFA deficient animals, indicate that brain weights are already reduced in 10-day-old deficient rats, that brain phospholipids decrease, especially in the males after three months, and that fatty acid distribution changes begin rather early. The latter consist of a decrease of tetraenes and increase of trienes and of the triene-tetraene ratios as early as at 10 days, a decrease of hexaenes after six months, and after six months, an increase of pentaenes, which are elevated at birth but usually disappear after three months of age. Similar changes are observed in myelin. The induced changes are not completely reversed upon return to normal diet.
TL;DR: A catabolic pathway involving oxidation of the hydrocarbon to a secondary alcohol and the corresponding ketone, followed by the formation and subsequent cleavage of an ester intermediate is presented.
Abstract: Oxidation ofn-alkanes and alk-1-enes by aPenicillium species andPseudomonas aeruginosa resulted in the formation of intermediates arising from the oxidation of methylene groups. A catabolic pathway involving oxidation of the hydrocarbon to a secondary alcohol and the corresponding ketone, followed by the formation and subsequent cleavage of an ester intermediate is presented.
TL;DR: The fatty acid compositions of the blubber and melon oils from the beluga whale have been determined by gas liquid chromatography (GLC), and an unusual compound may play a role in the echolocation system of theBeluga whale.
Abstract: The fatty acid compositions of the blubber and melon oils from the beluga whale (Delphinapterus leucas) have been determined by gas liquid chromatography (GLC). The melon oil contains a high level (60.1 mole %) of isovaleric acid, substantial amounts of long chain branched acids (16.9%), and very little polyunsaturated material (0.5%). The blubber oil contains less isovaleric (13.2%), fewer long chain branched acids (2.7%), and appreciable amounts (10.9%) of the polyunsaturated acids typical of marine oils. The blubber and melon oils were also examined for lipid class composition by thin layer chromatography on silicic acid, direct GLC of the hydrogenated oil, and gel permeation chromatography. Both oils are composed almost entirely of triglycerides, which can be separated chromatographically into molecules containing 0, 1 and 2 isovaleric acid moieties. No triisovalerin could be detected. The blubber oil contains 68.9 mole % normal triacyl-, 24.2% diacyl-monoisovaleroyl-, and 7.0% monoacyl-diisovaleroyl-triglycerides (acyl=long chain acid). Monoacyl-diisovalerin constitutes 86.7 mole % of the melon oil. This unusual compound may play a role in the echolocation system of the beluga whale.
TL;DR: Analysis of amino acid content at two distinctly different periods in the reaction substantiate the hypothesis that radicals and not aldehydes are a major cause of protein damage.
Abstract: The free radical concentration in lipid-protein mixtures with a low moisture content was monitored both during and after the time that the lipid actively absorbed oxygen. The data show that, in dry systems, the decay in radical content is followed by a rise in malonaldehyde protein fluorescence. Analysis of amino acid content at two distinctly different periods in the reaction substantiate the hypothesis that radicals and not aldehydes are a major cause of protein damage.
TL;DR: By combined gas liquid chromatography-mass spectrometry a series of monomethyl branched fatty acids was found in the fatty acid moiety of the wax esters of vernix caseosa, and except for the iso acids and possibly some of the anteiso acids, these could be formed by replacement of malonyl CoA with a molecule of methyl malonyL CoA at the point of the branch.
Abstract: By combined gas liquid chromatography-mass spectrometry a series of monomethyl branched fatty acids was found in the fatty acid moiety of the wax esters of vernix caseosa. The methyl branch occurred on the even C-atoms of chains ranging from C11 to C17 (some 43 compounds in all). Except for the iso acids and possibly some of the anteiso acids, these could be formed by replacement of malonyl CoA with a molecule of methyl malonyl CoA at the point of the branch. Smaller amounts of fatty acids also were found with two methyl branches occurring on the even C-atoms of chains ranging from C9 to C15.
TL;DR: In this article, Brockerhoff-type procedures were used to determine the amounts of each acyl group at each glyceride position of Limnanthes douglasii seed oil.
Abstract: Brockerhoff-type procedures were used to determine the amounts of each acyl group at each glyceride position ofLimnanthes douglasii seed oil. During the course of the analyses, small quantities of three acids isomeric with those previously found in the oil were identified by their ozonolysis products and their gas-liquid chromatographic (GLC) behavior. The newly discovered constituents of the oil were 3-octadecenoic acid (0.1%), 5-octadecenoic acid (0.9%) and 11-eicosenoic acid (3%). The saturated acids and those with ω-9-unsaturation are esterified most often to β-glyceride positions inLimnanthes seed, while the acids with Δ5-unsaturation occur generally at the outer glyceride positions. Although the Δ5-unsaturated acids as a group exhibited no obvious preference for one outer position over the other, individual acids were unequally distributed between the 1- and 3-sn-glycerol positions. The probabilities of occurrence of the various triglycerides were calculated from the stereospecific analysis data by assuming a 1-random, 2-random, 3-random distribution of the acyl groups. The calculations are in agreement with the composition of the whole oil, as determined by GLC.
TL;DR: Procedures have been developed for the synthesis of both enantiomeric forms of mixed fatty acid, saturated and polyunsaturated 1,2-diacyl-sn-glycerols and 2,3-diACYl- Sn- glycerols from D-mannitol as starting material.
Abstract: Procedures have been developed for the synthesis of both enantiomeric forms of mixed fatty acid, saturated and polyunsaturated 1,2-diacyl-sn-glycerols and 2,3-diacyl-sn-glycerols from D-mannitol as starting material. The following diacyl-sn-glycerols have been synthesized: 1-Stearoyl-2-linoleoyl-sn-glycerol, 1-stearoyl-2-linolenoyl-sn-glycerol, 2-linoleoyl-3-stearoyl-sn-glycerol and 2-linolenoyl-3-oleoyl-sn-glycerol. Their specific rotations, refractive indices, densities, solubilities, carbon and hydrogen analysis and iodine values have been reported.
TL;DR: Several monoazasterols were found to be potent inhibitors of Δ24- and Δ22,24- reductase enzyme(s) in the tobacco hornworm,Manduca sexta (Johannson).
Abstract: Several monoazasterols were found to be potent inhibitors of Δ24- and Δ22,24- reductase enzyme(s) in the tobacco hornworm,Manduca sexta (Johannson). Certain of these inhibitors also prevented normal larval development and pupation in the hornworm at dietary concentrations in the parts per million range. Comparative studies with several different insects indicated differences between the species with respect to the effects of the azasterols. The relationship of azasterol structure to the inhibitory effect(s) on sterol metabolism and larval development is discussed.
TL;DR: It was found that this pig lung surfactant contained the phospholipid constituents known to be present in mammalian tissues and in addition, phosphatidylglycerol (1.5%) and lyso-bisphosphatidic acid (2.0%) were also found.
Abstract: Surface active material (surfactant), which contained 80% lipid material, was isolated from pig lungs by the saline perfusion procedure. The lipids were analyzed by column, thin layer and paper chromatography, followed by gas liquid chromatography to determine the fatty acid composition of the major phospholipid fractions. It was found that this pig lung surfactant contained the phospholipid constituents known to be present in mammalian tissues and in addition, phosphatidylglycerol (1.5%) and lyso-bisphosphatidic acid (2.0%) were also found. These two components occurred in higher proportions in the surfactant lipids than in the lipids of the whole lung tissues.
TL;DR: This paper is a review of some of the work being done at the author's laboratory on phospholipids and glycolipids of the alga, Chlorella vulgaris, implicated in fatty acid transformations such as chain elongation and desaturation.
Abstract: This paper is a review of some of the work being done at the author's laboratory. The phospholipids and glycolipids of the alga,Chlorella vulgaris, have been implicated in fatty acid transformations such as chain elongation and desaturation. Labeling studies with [14C] acetate have shown that newly synthesized galactosyl glycerides have mainly saturated fatty acids. Subsequent to de novo synthesis, a series of alterations of fatty acid structure takes place within the same glycolipid molecules. The specific incorporation of [14C] oleic acid intoChlorella phosphatidyl choline provides a convenient model system for studying the lipid dependent desaturation of oleic to linoleic acid. The inhibitor of fatty acid desaturation, sterculic acid, only inhibits the conversion of oleate into linoleate if added before the precursor fatty acid has been incorporated into a complex lipid. Studies with isomeric monoenoic fatty acids have suggested that there are two enzymes which catalyze the formation of linoleic from oleic acid. One measures the position of the second double bond from the carboxyl group, the other, from the methyl end of the chain. The latter enzyme probably requires the complex lipid substrate.
TL;DR: The biosynthesis of tetrahymanol has been shown by appropriate labeling studies to involve a direct, nonoxidative, proton-initiated cyclization of squalene rather than the more commonly found type of mechanism involvingSqualene 2,3-oxide as an intermediate.
Abstract: Sterols are not found inTetrahymena pyriformis when this protozoan is grown in a medium free from exogenous sterols; instead, the principal solid alcohol that can be isolated from the organism is tetrahymanol. a pentacyclic triterpenoid alcohol with an unusual structure. The biosynthesis of tetrahymanol has been shown by appropriate labeling studies to involve a direct, nonoxidative, proton-initiated cyclization of squalene rather than the more commonly found type of mechanism involving squalene 2,3-oxide as an intermediate. In contrast, whenT. pyriformis is incubated with any one of a wide variety of added sterols, the biosynthesis of tetrahymanol is inhibited and the added sterol is accumulated by the organism and, in most cases, is converted metabolically into one or more other sterols. Four different types of transformation have been observed: the introduction of Δ5, Δ7 and Δ22 double bonds, and the removal of ethyl groups, but not methyl groups, from C-24.
TL;DR: The importance of phospholipids in the taxonomy of the actinomycetes and related eubacteria is discussed, and the mannophosphoinositides of the corynebacteria are discussed.
Abstract: The phospholipids ofCorynebacterium diphtheriae, Corynebacterium xerosis, Corynebacterium equi andCorynebacterium ovis were examined, largely by chromatographic procedures. In all of these, lipids of the phosphoinositide and mannophosphoinositide type were prominent. In contrast to the mycobacteria, the mannophosphoinositides of the corynebacteria were all dimannophosphoinositides; however, as in mycobacteria, these dimannophosphoinositides apparently occurred in the diacylated and triacylated forms—the tetraacylated component prominent in mycobacteria was absent. Phosphatidylethanolamine and phosphatidylserine were also absent. InCorynebacterium diphtheriae the major single phospholipid corresponded to phosphatidylglycerol: cardiolipin also appeared to be a major lipid. The fatty acids of the corynebacterial phospholipids were distinguished by the presence of branched chain isomers of medium chain length. The importance of phospholipids in the taxonomy of the actinomycetes and related eubacteria is discussed.
TL;DR: Examination of the intact lipids, the derived fatty acids and thederived fatty alcohols by gas chromatography reveals that the blubber triglycerides show characteristics of freshwater fish fats, but the jaw fat lipids have several distinctive features.
Abstract: The lower jaw fat of the Amazon River dolphinInia geoffrensis contains 52.8% wax ester, 44.7% triglyceride and 2.5% diacyl glyceryl ether, while its dorsal blubber fat is >98% triglyceride. Examination of the intact lipids, the derived fatty acids and the derived fatty alcohols by gas chromatography reveals that the blubber triglycerides show characteristics of freshwater fish fats, but the jaw fat lipids have several distinctive features. Jaw fat wax esters, triglycerides and diacyl glyceryl ethers are all rich in C10, C12 and C14 fatty acids and contain no polyunsaturated acids. The fatty alcohols in the wax esters are over 90% saturated. The major carbon numbers in the jaw fat triglycerides (C38–C46) are considerably lower than those of the blubber triglycerides (C48–C54). The possible adaptation of the jaw lipids for use in the underwater echolocation process of this dolphin is discussed.