Showing papers in "Lipids in 1974"
TL;DR: If an interval of 12 atomic mass units is observed between the most intense peaks of clusters of fragments containing n and n−1 carbon atoms of the acid moiety, the double bond occurs between carbons n andn+1 in the molecule
Abstract: Mass spectra of pyrrolidides of monounsaturated straight chain fatty acids are presented and discussed. The spectra of pyrrolidides contain mainly ions from the polar part of the molecule. This gives simple spectra from which double bond positions can be deduced directly. If an interval of 12 atomic mass units is observed between the most intense peaks of clusters of fragments containing n and n−1 carbon atoms of the acid moiety, the double bond occurs between carbons n and n+1 in the molecule This rule is valid for double bonds occurring at positions Δ5-Δ15 in an 18-carbon chain and has been applied to acids having 10–24 carbon atoms.
252 citations
TL;DR: It is interpreted to mean that the primary role sterols play in nature is a nonmetabolic one as architectural components of membranes and that this role can be played, but less well, by other molecules which approximate the steroidal structure.
Abstract: Sterols, or in rare cases structurally similar molecules, are biosynthesized or at least required by all eucaryotic organisms, as well as by many procaryotic ones, regardless of their status as plants, animals, or protista. This information, together with quantitative, structural, metabolic, and other data is reviewed. It is interpreted to mean that the primary role sterols play in nature is a nonmetabolic one as architectural components of membranes and that this role can be played, but less well, by other molecules which approximate the steroidal structure. The biosynthetic process should, therefore, and actually does not appear to be correlatable with this role, which, in turn, is correlatable with phylogenesis. The Δ24-reduction-alkylation bifurcation, for instance appears to be interrelated profoundly with the evolutionary differentiation of the animal from the plant kingdom.
250 citations
TL;DR: Lp(a) lipoprotein was not significantly correlated with age, sex, or cholesterol or glyceride concentrations, and both within-assay and between-assays coefficients of variation were inversely concentration dependent.
Abstract: The Lp(a) lipoprotein was purified from human plasma by ultracentrifugation and gel filtration on 6% agarose. It contained 27% protein, 65% lipid, and 8% carbohydrate. Quantification of the Lp(a) lipoprotein was performed by radial immunodiffusion. Both within-assay and between-assay coefficients of variation were inversely concentration dependent, decreasing from 20% and 27%, respectively, at 3 mg/100 ml to 7% and 12%, respectively, at concentrations above 8 mg/100 ml. The lower limit of sensitivity of the assay was 1.5 mg/100 ml. Of 340 unrelated fasting subjects tested, 81% had levels of the Lp(a) lipoprotein exceeding this lower limit. The distribution of Lp(a) concentrations in this population was skewed with a mean of 14 mg/100 ml and a median of 8 mg/100 ml. Lp(a) lipoprotein was not significantly correlated with age, sex, or cholesterol or glyceride concentrations.
208 citations
TL;DR: It is suggested that the intrinsic proteins of membranes are held in position by hydrogen bonding, as well as by hydrophobic and electrostatic forces, and that hydrogen bonding also mediates the penetration of membranes by proteins.
Abstract: Membranes are proposed to consist of a hydrophobic core, two hydrogen belts, and two polar zones The hydrogen belts consist of hydrogen bond acceptors, ie the carbonyl groups of phospholipids and sphingolipids, and hydrogen bond donors, ie the labile hydrogens of cholesterol, sphingosine, proteins, and water The density of anhydrous hydrogen bonding and the impermeability of the membrane increase with increasing concentrations of cholesterol, sphingolipids, α-hydroxy acyl residues, plasmalogens, and ether phospholipids Cholesterol owes its membrane-closing properties to its rigid longitudinal orientation in the membrane combined with the latitudinal orientation of the O−H bond It is suggested that the intrinsic proteins of membranes are held in position by hydrogen bonding, as well as by hydrophobic and electrostatic forces, and that hydrogen bonding also mediates the penetration of membranes by proteins
203 citations
TL;DR: In this paper, the structure and composition of potato tuber skin (suberin) were determined by combined gas chromatography-mass spectrometry, and a method of distinguishing between suberin and cutin and a biosynthetic pathway was suggested.
Abstract: Potato tuber skin (suberin), isolated enzymatically, was depolymerized with BF3-CH3OH, and the structure and composition of the aliphatic monomers were determined by combined gas chromatography-mass spectrometry. 18-Hydroxyoctadec-9-enoic acid and octadec-9-ene-1,18-dioic acid were the major components. Products of epoxidation and subsequent hydration of the Δ9 double bond of these compounds, 10,16-dihydroxy hexadecanoic acid, and much smaller quantities of 9,16-dihydroxyhexadecanoic acid and 8,16-dihydroxyhexadecanoic acid also were present. The other significant feature of the monomer composition of potato skin was that it contained substantial quantities of C20−C28 fatty acids, fatty alcohols, and ω-hydroxy acids. Based upon these studies, a method of distinguishing between suberin and cutin and a biosynthetic pathway for suberin monomers are suggested.
162 citations
TL;DR: In this article, an isomeric mixture of linoleic acid hydroperoxides, 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid (79%), 9-hydroxperoxy cis-12,transtrans-10-decomposed 10,12-decomposition acid (21%), was decomposed homolytically by Fe(II) in an ethanol-water solution.
Abstract: An isomeric mixture of linoleic acid hydroperoxides, 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid (79%) and 9-hydroperoxy-cis-12,trans-10-octadecadienoic acid (21%), was decomposed homolytically by Fe(II) in an ethanol-water solution. In one series of experiments, the hydroperoxides were decomposed by catalytic concentrations of Fe(II). The 10−5 M Fe(III) used to initiate the decomposition was kept reduced as Fe(II) by a high concentration of cysteine added to the reaction in molar excess of the hydroperoxides. Nine different monomeric (no detectable dimeric) fatty acids were identified from the reaction. Analyses of these fatty acids revealed that they were mixtures of positional isomers identified as follows: (I) 13-oxo-trans,trans-(andcis,trans-) 9,11-octadecadienoic and 9-oxo-trans,trans- (andcis,trans-) 10,12-octadecadienoic acids; (II) 13-oxo-trans-9,10-epoxy-trans-11-octadecenoic and 9-oxo-trans-12, 13-epoxy-trans-10-octadecenoic acids; (III) 13-oxo-cis-9,10-epoxy-trans-11-octadecenoic and 9-oxo-cis-12, 13-epoxy-trans-10-octadecenoic acids; (IV) 13-hydroxy-9,11-octadecadienoic and 9-hydroxy-10,12-octadecadienoic acids; (V) 11-hydroxy-trans-12, 13-epoxy-cis-9-octadecenoic and 11-hydroxy-trans-9, 10-epoxy-cis-12-octadecenoic acids; (VI) 11-hydroxy-trans-12, 13-epoxy-trans-9-octadecenoic and 11-hydroxy-trans-9,10-epoxy-trans-12-octadecenoic acids; (VII) 13-oxo-9-hydroxy-trans-10-octadecenoic acids; (VIII) isomeric mixtures of 9, 12, 13-dihydroxyethoxy-trans-10-octadecenoic and 9, 10, 13-dihydroxyethoxy-trans-11-octadecenoic acids; and (IX) 9, 12, 13-trihydroxy-trans-10-octadecenoic and 9, 10, 13-trihydroxy-trans-11-octadecenoic acids. In another experiment, equimolar amounts of Fe(II) and hydroperoxide were reacted in the absence of cysteine. A large proportion of dimeric fatty acids and a smaller amount of monomeric fatty acids resulted. The monomeric fatty acids were examined by gas liquid chromatography-mass spectroscopy. Spectra indicated that the monomers were largely similar to those produced by the Fe(III)-cysteine reaction.
148 citations
TL;DR: A method is described for quantitatively determining lipid phosphorus with a linear range from 0.7–10.0 μg, requiring one stable reagent and a single extraction with 1-butyl acetate after the phosphorus is converted to inorganic phosphate by means of a perchlorate digestion.
Abstract: A method is described for quantitatively determining lipid phosphorus with a linear range from 0.7–10.0 μg. The method is simple and rapid, requiring one stable reagent and a single extraction with 1-butyl acetate after the phosphorus is converted to inorganic phosphate by means of a perchlorate digestion. The stable complex is read at 310 nm.
143 citations
TL;DR: Pair feeding studies demonstrated that the reduction in food intake accounted for the decrease in wt gain and body lipid observed with (−)-hydroxycitrate treatment.
Abstract: These studies were designed to determine the effect of (−)-hydroxycitrate upon the accumulation of lipid in the rat by examining appetite, wt gain, and total body lipid profiles. The chronic oral administration of a nontoxic dose of (−)-hydroxycitrate to growing rats for 11–30 days caused a significant reduction in body wt gain, food consumption, and total body lipid. The administration of equimolar amounts of citrate did not alter wt gain, appetite, or body lipid. No increase in liver size or liver lipid content occurred with either treatment. Pair feeding studies demonstrated that the reduction in food intake accounted for the decrease in wt gain and body lipid observed with (−)-hydroxycitrate treatment.
136 citations
TL;DR: Rats receiving (−)-hydroxycitrate consumed less food than the untreated controls; however, this decreased caloric intake was not responsible for the drug induced depression of hepatic lipogenesis, as shown by studies using pair fed rats.
Abstract: The purpose of these investigations was to ascertain the effect of (−)-hydroxycitrate on the accumulation of lipid in the meal fed rat by examining the rates of lipogenesis after acute and chronic treatment. Oral administration of (−)-hydroxycitrate depressed significantly the in vivo lipogenic rates in a dose-dependent manner in the liver, adipose tissue, and small intestine. The hepatic inhibition was significant for the 8 hr period, when control animals demonstrated elevated rates of lipid synthesis. The kinetics of this reduction of in vivo hepatic lipogenesis were identical after acute or chronic administration of (−)-hydroxycitrate. However, in vitro rates of lipogenesis were elevated after chronic administration of (−)-hydroxycitrate for 30 days. Rats receiving (−)-hydroxycitrate consumed less food than the untreated controls; however, this decreased caloric intake was not responsible for the drug induced depression of hepatic lipogenesis, as shown by studies using pair fed rats.
127 citations
TL;DR: The unsaponifiables from threeTheaceae oils and alfalfa, garden balsam, and spinach seed oils and shea fat were separated into four fractions: sterols, 4-methylsterols, triterpene alcohols, and less polar compounds by thin layer chromatography.
Abstract: The unsaponifiables from threeTheaceae (Camellia japonica L.,Camellia Sasanqua Thunb., andThea sinensis L.) oils and alfalfa, garden balsam, and spinach seed oils and shea fat were separated into four fractions: sterols, 4-methylsterols, triterpene alcohols, and less polar compounds by thin layer chromatography. While the sterol fraction was the major one for the unsaponifiables from alfalfa and spinach seed oils, the triterpene alcohol fraction was predominant for the unsaponifiables from all other oils. The sterol, 4-methylsterol, and triterpene alcohol fractions were analyzed by gas chromatography. All the sterol fractions were alike in their compositions, consisting exclusively of Δ7-sterols, such as α-spinasterol and Δ7-stigmastenol as predominant components together with Δ7-avenasterol and 24-methylcholest-7-enol. Obtusifoliol, gramisterol (occasionally accompanied with cycloeucalenol), and citrostadienol, together with several other unidentified components, were found in the 4-methylsterol fractions from all of the oils except shea fat. The 4-methylsterol fraction from shea fat showed a characteristic composition containing a large proportion of unidentified components which had relative retention time greater than that of citrostadienol, while no citrostadienol was detected. β-Amyrin, lupeol, and butyospermol were major components of the triterpene alcohol fractions from most of the oils, but the fraction from spinach seed oil contained cycloartenol and 24-methylene-cycloartanol as predominant components. There is a close similarity in the compositions of unsaponifiables (sterols, 4-methylsterols, and triterpene alcohols) of the threeTheaceae oils. Two sterols, α-spinasterol and Δ7-stigmastenol, and five triterpene alcohols were isolated from tea seed oil. Moreover, five unidentified components beside parkeol, butyrospermol, α-amyrin, and lupeol were isolated from the triterpene alcohol fraction of shea fat.
110 citations
TL;DR: The presence in Northern Pike liver and testes lipids of a group of eight homologous fatty acids of as yet unknown structure is reported, characterized by being more resistant to hydrogenation than normal unsaturated fatty acids and by an inability to form urea inclusion compounds.
Abstract: The presence in Northern Pike (Esox locius) liver and testes lipids of a group of eight homologous fatty acids of as yet unknown structure is reported. They occur esterified to cholesterol and to glycerol as triglycerides but are absent from the phospholipids. They contain three oxygens and are characterized further by being more resistant to hydrogenation than normal unsaturated fatty acids and by an inability to form urea inclusion compounds. They also have been found to be major constituents of the liver fatty acids of four additional species of fish.
TL;DR: It was shown that, keeping the pH low during the partition of lipids by the Bligh and Dyer method, most of the acyl and alkyl dihydroxyacetone phosphate were recovered in the chloroform-rich phase.
Abstract: Chloroform-methanol mixture was shown to extract acyl and alkyl dihydroxyacetone phosphate from enzyme incubation mixtures. However, when the lipid extract was washed with water to remove nonlipid materials, 70–80% of acyl and alkyl dihydroxyacetone phosphate were lost in the aqueous phase. It was shown that, keeping the pH low ( 95%) of the acyl and alkyl dihydroxyacetone phosphate were recovered in the chloroform-rich phase. n-Butanol was shown to extract 80–90% of these lipids from incubation mixtures at neutral pH.
TL;DR: The details of several distinct alkylation mechanisms, which are now recognized in a range of lower and higher plants, have been reviewed and may have some phylogenetic significance.
Abstract: The typical plant sterols contain a substituent at C-24 of the side chain. This can be a methylene, ethylidene, methyl, or ethyl group; with the last three groups, all possible isomers have been reported in nature. The C-24 alkyl groups are derived by a transmethylation reaction from methionine. The details of several distinct alkylation mechanisms, which are now recognized in a range of lower and higher plants, have been reviewed. The operation of these different routes may have some phylogenetic significance.
TL;DR: Fatty acid analysis of triglyceride and 1,3 diglyceride fractions indicated an increase in levels of fatty acid at high light intensity when compared to low lightintensity, while levels of polar lipid fatty acids increased at low light intensity.
Abstract: Total fatty acid, total sterol, fatty acids of specific lipid classes, and unsaturated fatty acids produced inNitzschia closterium were compared qualitatively and quantitatively as a function of changes in light intensity. Increased levels of total fatty acids were observed in cells grown at high light intensity when compared to cells grown at low light intensity. However, the percentage of unsaturated fatty acid decreased under high light conditions. Fatty acid analysis of triglyceride and 1,3 diglyceride fractions indicated an increase in levels of fatty acid at high light intensity when compared to low light intensity, while levels of polar lipid fatty acids increased at low light intensity. These analyses can be taken to indicate an increase in triglyceride and diglyceride at high light and a decrease in polar lipid at high light. Levels of free fatty acids did not differ significantly with light intensity. The levels of total sterol also were unaffected by changes in light intensity. However, levels of sterol isolated as free sterol and sterol associated in a yet unknown manner in the polar lipid fraction varied with changes in light intensity. Levels of polar lipid sterol increased at high light intensity compared to low light intensity, while the opposite was true for free sterol. The greatest percentage of total sterol was found in the polar lipid class regardless of light intensity.
TL;DR: The slow metabolism of lipid during starvation indicated that lipid stores in adult females may be conserved for egg production, and the polyunsaturation of the wax esters fatty acids suggest phytoplankton in the diet of adults and in the younger stages.
Abstract: All stages from egg to adult of the North Pacific copepod,Euchaeta japonica contained wax esters in their lipid stores, while triglycerides were important only in the eggs, early naupliar stages, and adults. The large lipid reserves of the eggs were wax esters and triglycerides (58% and 19% of the lipid, respectively), both of which were used rapidly during the early stages of development. Wax esters continued to decrease after triglycerides had been utilized completely for energy. The slow metabolism of lipid during starvation indicated that lipid stores in adult females may be conserved for egg production. The dominant alcohols of the wax esters of all stages were tetradecanol (24–42% of the total) and hexadecanol (25–65%). Only minor amounts of polyunsaturated alcohols were observed. There was, however, a high proportion of polyunsaturation in the wax ester fatty acids, even though octadecenoic was generally predominant (16–46% of the total wax ester fatty acids). The polyunsaturation of the wax esters fatty acids and the presence of 21∶6 hydrocarbon suggest phytoplankton in the diet of adults and in the younger stages. Cholesterol was the main sterol, but there were minor amounts of desmosterol (1–12% of the total sterols) present. The latter sterol has not been found previously in copepods, although reported from Cirripedia and Decapoda.
TL;DR: The moldGeotrichum candidum produces an extracellular lipase, readily concentrated by removal of the culture medium in which the microorganism is grown, which has an optimum pH of 8.2, and the lyophilized powder is extremely stable, retaining activity for at least eight years when stored at-20 C.
Abstract: The moldGeotrichum candidum produces an extracellular lipase, readily concentrated by removal of the culture medium in which the microorganism is grown. The lipase is characterized by a unique, but not absolute, specificity for fatty acids containingcis-9 orcis,cis-9, 12 unsaturation, hydrolyzing both regardless of position within the triglyceride molecule. The enzyme also hydrolyzescis-9-16∶1,cis,trans-9,12-18∶2,trans,cis-9,12-18∶2, palmitoyl oleate and cholesteryl oleate. Digested at comparatively slow rates are:trans,trans-9,12-18∶2, double bond positional isomers of 18∶1 (other thancis-9), stearolic acid, oleoylpalmitate, dilinoleoyl phosphatidyl choline, and saturated acids. The enzyme has an optimum pH of 8.2, and the lyophilized powder is extremely stable, retaining activity for at least eight years when stored at-20 C. A purification of 81-fold has been achieved.
TL;DR: In this article, the unsaponifiable fractions of soybean, cottonseed, coconut, olive, and avocado oils have been studied in detail and the presence of absence of individual unsaponiferous components may help in establishing the identity of each of the investigated oils and in detecting of admixture by another oil.
Abstract: The unsaponifiable fractions of soybean, cottonseed, coconut, olive, and avocado oils have been studied in detail. The oils differed in the contents of total unsaponifiables, squalene, tocopherols, and sterols and also in the composition of the tocopherol and sterol fractions. The presence of absence of individual unsaponifiable components may help in establishing the identity of each of the investigated oils and in detecting of admixture by another oil.
TL;DR: The fatty acids of four strains of extremely thermophilic bacteria and three strains of moderately thermophile bacteria were examined by gas liquid chromatography, and the changes of its fatty acid composition were studied.
Abstract: The fatty acids of three strains of extremely thermophilic bacteria and three strains of moderately thermophilic bacteria were examined by gas liquid chromatography. All the thermophiles contained straight, iso, and ante-iso branched fatty acids. Iso C17∶0 acid was abundant in both the moderately thermophilic strains (10–33%) and the extremely thermophilic strains (50–61%). The pair of fatty acids iso C15∶0 and iso C17∶0 was the predominant pair in both the moderately (34–64%) and extremely (76–87%) thermophilic strains. The pair of fatty acids ante-iso C15∶0 and ante-iso C17∶0 was present in larger amount in moderately (25–34%) than in extremely (8.5–15%) thermophilic strains. No hydroxy cyclopropane, or unsaturated fatty acids were found. One extreme thermophile,Flavobacterium thermophilum HB-8 was grown at 6 different culture temperatures from 49–82 C, and the changes of its fatty acid composition were studied. The ratios of iso C17∶0/iso C15∶0 and ante-iso C17∶0/ante-iso C15∶0 were much greater at higher culture temperatures, indicating chain elongation.
TL;DR: A new pathway for ethanol metabolism, the microsomal ethanol oxidizing system, which doubles in activity after ethanol feeding is described, which may contribute to the understanding of increased cholesterol and lipoprotein synthesis.
Abstract: Ethanol abuse produces fatty liver which cannot be prevented by supplementation in protein, minerals, vitamins, and choline. In rats, protein and choline deficiencies potentiate the effect, whereas replacement of dietary fat by medium chain triglycerides or carbohydrates decreases the capacity of ethanol to produce steatosis. Administration of a single dose of ethanol to rats represents a stressful condition associated with moderate hepatic accumulation of fatty acids derived from adipose tissue. By contrast, chronic ethanol administration produces more pronounced steatosis with a predominance of endogenously synthesized and, when available, dietary fatty acids. These accumulate because of decreased fat oxidation. Ethanol also stimulates hepatic lipogenesis. These various effects can be explained by the increase in the hepatic nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide ratio secondary to the oxidation of ethanol via the alcohol dehydrogenase pathway. In addition there are more lasting changes in intermediary metabolism, such as increased hepatic ketogenesis which could be linked to the persistent alteration in mitochondrial function and structure found after chronic ethanol ingestion. The ultrastructural changes also are characterized by proliferation of the hepatic smooth endoplasmic reticulum. The latter was documented by subfraction. This led to the description of a new pathway for ethanol metabolism, the microsomal ethanol oxidizing system, which doubles in activity after ethanol feeding. The existence of the microsomal ethanol oxidizing system may contribute to our understanding of increased cholesterol and lipoprotein synthesis. Other effects upon lipid metabolism include decreases in free fatty acids and glycerol concentrations and free fatty acid turnover which result from inhibition of peripheral fat mobilization by acetate, a metabolite of ethanol.
TL;DR: The maximum level of cellular cholesteryl esters obtained with individual samples of hyperlipemic rabbit serum is correlated with the cholesterol content of the original sera, even when the incubation medium is adjusted to a constant concentration of cholesterol.
Abstract: Exposure of Fu5AH rat hepatoma tissue culture cells to hyperlipemic rabbit serum results in the accumulation of cellular cholesteryl esters. Accumulation is not a characteristic of all cells in culture, as evidenced by the lack of response of mouse and human fibroblasts. Fu5AH cells grown for 24 hr on 5% hyperlipemic rabbit serum have an 8- to 12-fold increase of cellular cholesteryl esters, small increases in free cholesterol and triglycerides, and no change in phospholipids, when compared to cells grown in normal rabbit serum. Rapid accumulation of cholesteryl esters occurs during the first 8–12 hr of incubation, and maximum cellular concentration is achieved within 24 hr. The maximum level of cellular cholesteryl esters obtained with individual samples of hyperlipemic rabbit serum is correlated with the cholesterol content of the original sera, even when the incubation medium is adjusted to a constant concentration of cholesterol. Heating hyperlipemic rabbit serum (60 C/30 min) does not destroy activity; however, no cholesteryl ester accumulation occurs in heated cells. The stimulatory activity of hyperlipemic rabbit serum primarily is associated with lipoproteins having densities <1.006. High levels of cellular cholesteryl ester are associated with the appearance of cytoplasmic vacuoles containing cholesteryl esters. The increase in cellular cholesteryl esters is accompanied by a decrease of the cholesteryl esters in the growth medium. Cellular cholesteryl esters are not rapidly hydrolyzed or released upon removal of hyperlipemic rabbit serum.
TL;DR: The method is applied to the quantification of alkyl and alk-1-enyl glycerols derived from total lipids of rat heart, liver, testes, and brain and of various transplantable tumors, i.e. amelanotic melanoma, melanoma B16, sarcoma T241, and Novikoff hepatoma.
Abstract: A method is described for the quantification of the constituentO-alkyl andO-alk-1-enyl glycerols of neutral lipids or phospholipids. The method involves chemical degradation, the preparation of derivatives, and quantification by gas chromatography using internal standards. Alk-1-enyl moieties are converted to alkyl substituted dioxanes in the presence of 1,1-dimethoxyheptadecane as standard; alkyl glycerols are analyzed as isopropylidene derivatives using 1-O-heptadecyl glycerol as internal standard. The method is applied to the quantification of alkyl and alk-1-enyl glycerols derived from total lipids of rat heart, liver, testes, and brain and of various transplantable tumors, i.e. amelanotic melanoma, melanoma B16, sarcoma T241, and Novikoff hepatoma. The levels of alkyl glycerols range from 0.11–1.07% total lipids and those of alk-1-enyl glycerols from 0.49–5.03%. The data are compared to those obtained by other methods.
TL;DR: Measurements of fluorescence intensity showed that the fluorescence of these compounds was quenched at basic pH and that it was restored by adjustment of pH to neutrality.
Abstract: The effects of pH and of the metal chelator, europium (Tric[2,2,6,6-tetra-methyl-3,5-heptanedionate]), upon fluorescence of lipid peroxidation products were tested, and fluorescence decay times and fluorescence polarization values were determined. Measurements of fluorescence intensity showed that the fluorescence of these compounds was quenched at basic pH and that it was restored by adjustment of pH to neutrality. Metal chelator decreased the fluorescence intensity 8–15%. pH Effects and metal coordination effects are useful for analysis and characterization of these fluorescent products. Fluorescence polarization and fluorescence decay times are also useful analytical techniques for characterization of fluorescent products.
TL;DR: The influence of dietary rapeseed oil on the lipid classes and fatty acid pattern of rat heart homogenate and mitochondria has been investigated and cardiolipin, a component of the inner membrane of mitochondria its high affinity for erucic acid, might influence the normal function of the internal membrane of heart mitochondria.
Abstract: The influence of dietary rapeseed oil on the lipid classes and fatty acid pattern of rat heart homogenate and mitochondria has been investigated after feeding a diet with 9.8% by wt erucic acid for 10 days and 1.4% and 2.6% erucic acid for 28 days. The rats treated with 9.8% erucic acid showed a significant increase in the triglycerides of the heart mitochondria. This tendency was much less pronounced in rats treated with 1.4 and 2.6% erucic acid, respectively. In all experiments, the triglycerides of the heart mitochondria showed a high content of erucic acid. The fatty acids of phosphatidylcholine, phosphatidylethanolamine, and cardiolipin were all influenced by the dietary rapeseed oil, but the erucic acid seemed to have a specific affinity to cardiolipin. Cardiolipin of rat heart mitochondria was isolated and identified with gas chromatography and mass spectrometry. The isolated cardiolipin was found to contain 12% erucic acid after feeding 9.8% erucic acid as rapeseed oil for 10 days. Similar results were obtained after feeding glyceryl trierucate for 5 days to rats. The incorporation of erucic acid into cardiolipin was followed by a corresponding decrease of linoleic acid. This observation is of great interest because the molecular structure of fatty acids in lipid molecules has a profound influence on the packing of these molecules in a bilayer. Since cardiolipin is a component of the inner membrane of mitochondria its high affinity for erucic acid might influence the normal function of the inner membrane of heart mitochondria.
TL;DR: The unsaponifiables separated from 20 vegetable oils were divided into sterol and three other (less polar compound, triterpene alcohol, and 4-methylsterol) fractions by preparative thin layer chromatography as mentioned in this paper.
Abstract: The unsaponifiables separated from 20 vegetable oils were divided into sterol and three other (less polar compound, triterpene alcohol, and 4-methylsterol) fractions by preparative thin layer chromatography. The amounts of the sterol fractions were more than ca. 30% in the unsaponifiables from all of the oils, except tohaku, pumpkin seed, and fagara seed oils. Composition of the sterol fractions were determined by gas liquid chromatography. Individual components of the sterol fractions were identified by gas liquid chromatography and combined gas liquid chromatography-mass spectrometry. β-Sitosterol was found as the most predominant component in the sterol fractions from all oils, except two, i.e. the sterol fraction from pumpkin seed oil contained no detectable amount of β-sitosterol and the sterol fraction from akamegashiwa oil contained Δ5-avenasterol as the most abundant component. Campesterol, stigmasterol, Δ5-avenasterol, Δ7-stigmastenol, and Δ7-avenasterol and also trace amounts (at the very least) of cholesterol and brassicasterol were found in most of the oils analyzed. It may be noted that a large amount (ca. 9%) of cholesterol was detected in the sterol fraction from capsicum seed oil. The presence of 24-methylenecholesterol and Δ5-avenasterol in the sterol fraction of akamegashiwa oil was demonstrated by isolation of these sterols.
TL;DR: It is hypothesized that the small amounts of the 1,2-diacylglycerols present may have arisen from a reversal of lipolysis also catalyzed by this enzyme, and suggest that lipoprotein lipase may favor attack on the sn-1 position.
Abstract: The stereochemical course of the hydrolysis of synthetic sn-glycerol-1-palmitate-2-oleate-3-linoleate, sn-glycerol-1,2-dipalmitate-3-oleate and their antipodes by pancreatic and milk lipoprotein lipase was investigated by thin layer and gas liquid chromatographies of the diacylglycerol intermediates. The enzymic hydrolyses were made with bile salts or lysolecithin in a 1∶1 molar ratio to the substrate as emulsifiers and were limited to short time intervals which minimized isomerization and the reversal of lipolysis. In all instances, the products of hydrolysis by lipoprotein lipase contained a marked preponderance of the 2,3-diacylglycerols, while the composition of the diacylglycerol intermediates in the products of pancreatic lipase varied with the nature of the fatty acid in the 1 and 3 positions of the triacylglycerol molecule. Pancreatic lipase, but not lipoprotein lipase, gave a preferential release of unsaturated fatty acids. The above results are similar to those obtained with radioactive trioleoylglycerol and conventional stereospecific analyses and suggest that lipoprotein lipase may favor attack on the sn-1 position. It is hypothesized that the small amounts of the 1,2-diacylglycerols present may have arisen from a reversal of lipolysis also catalyzed by this enzyme.
TL;DR: In this article, the authors used thin layer chromatography on AgNO3-silicic acid to identify the major peaks with equivalent chain length values of 27.08 and 27.74.
Abstract: Fatty acid analysis of the total lipids from the marine spongeMicrociona prolifera by gas liquid chromatography on an EGSS-X column revealed two major peaks with equivalent chain length values of 27.08 and 27.74. Each of these components was isolated as a separate band by thin layer chromatography on AgNO3-silicic acid. Characterization of the two unknowns by IR spectroscopy, NMR, hydrogenation, and gas liquid chromatography revealed that the unknown acids weren-26∶2 andn-26∶3 containing only nonmethylene interruptedcis-double bonds. Reductive ozonolysis identified the 26∶2 ascis-5,cis-9-hexacosadienoic acid and the 26∶3 ascis-5,cis-9,cis-19-hexacosatrienoic acid. Analysis of the fatty acid composition ofMicrociona total lipids showed 14% 26∶2 and 31% 36∶3. The neutral lipids, phosphatidylethanomaline, and phosphatidylserine all contained >41% C26 acids; but only 4% C26 was present in the phosphatidylcholine.
TL;DR: Observed lipid droplets of renal papillae homogenates from four different species suggest that the interstitial cells produce these triglycerides, which could occur either by a transacylation from phospholipids and cholesterol esters and by a de novo synthesis from locally produced fatty acids.
Abstract: The lipid droplets of renal papillae homogenates from four different species were obtained by ultracentrifugation. Ca. 80–98% of the lipids (triglycerides, phospholipids, free fatty acids, and cholesterol esters) consist of triglycerides. The triglycerides were fractionated by argentation thin layer chromatography and each fraction characterized by gas liquid chromatography. No fraction contained any unique triglyceride. The fatty acid composition of the total triglycerides, as analyzed by gas liquid chromatography and ozonolysis, differed markedly from the fatty acid composition of the corresponding plasma triglycerides. The papillary triglycerides were characterized by higher concentrations of stearic acid, arachidic acid, and polyunsaturated acids with 20 or more carbon atoms. Particularly interesting was the presence in the lipid droplets of docosa-7,10,13,16-tetraenoic acid. This acid has been shown to be a major component in the cholesterol ester fraction of rat and canine adrenal lipids. In the papillary triglycerides, this acid accounted for 7%, 15%, and more than 20% of the total fatty acids in the dog, rat, and rabbit, respectively. The pig differs from these three species in having only ca. 1% of this acid. These observations suggest that the interstitial cells produce these triglycerides. This production could occur either by a transacylation from phospholipids and cholesterol esters and by a de novo synthesis from locally produced fatty acids. The possibility that the triglyceride production may be involved in a control of the prostaglandin production of the renal medulla is discussed.
TL;DR: An economical, simple, efficient system of deuterating saturated fatty acids at atmospheric pressure has been developed and yielded perdeuterated fatty acids of high isotopic purity with no evidence of other reaction products.
Abstract: An economical, simple, efficient system of deuterating saturated fatty acids at atmospheric pressure has been developed. Exchange is carried out between fatty acids and deuterium gas over palladium on charcoal catalyst at 195 C. The method was applied to even membered fatty acids containing from 6–14 carbon atoms. The method yielded perdeuterated fatty acids of high isotopic purity with no evidence of other reaction products.
TL;DR: The pyrrolidide is advantageous for fatty acid gas liquid Chromatography and mass spectrometry analyses because it can be prepared easily in high yield on a microscale, it is volatile enough for gas liquid chromatographic separations, and it has a simple and easily interpretable mass spectrum which indicates the structure.
Abstract: Amides of unsaturated fatty acids give mass spectra which indicate the locations of the double bonds. A survey of several amides of oleic acid was made to evaluate which amide might be most suitable for routine use in elucidation of structure. Methods of preparation of several amides of oleic acid are presented with mass spectral and gas chromatographic data. Tertiary amides have most easily interpretable mass psectra which indicate the position of the double bond in the fatty acid chain. The pyrrolidide is advantageous for fatty acid gas liquid chromatography and mass spectrometry analyses because it can be prepared easily in high yield on a microscale, it is volatile enough for gas liquid chromatographic separations, and it has a simple and easily interpretable mass spectrum which indicates the structure.
TL;DR: A convenient method for large or small scale preparation of psychosine from cerebroside has been developed by adaptation of published procedures.
Abstract: A convenient method for large or small scale preparation of psychosine from cerebroside has been developed by adaptation of published procedures. Cerebroside is refluxed with butanol and aqueous KOH, then the KOH is removed with perchloric acid. The fatty acids are removed by extraction with hexane and the excess perchloric acid is removed by partitioning between chloroform, ethanol, and water.