Occurrence of wax esters in the tissues of the organge roughy (Hoplostethus atlanticus)

The skin, skeleton and a fat-filled swim bladder of the orange roughy (Hoplostethus atlanticus) each contained greater than 20% lipid by wet weight which was almost entirely wax esters. These had carbon numbers of 34–40 consistent with the major fatty acid being 18∶1 and the major fatty alcohols being 16∶0, 18∶1, 20∶1 and 22∶1. In contrast, the liver and the roe contained appreciable quantities of glycerolipids with 18∶1 and 22∶6 as the major fatty acids.     

Effect of chronic ingestion of DDT on physiological and biochemical aspects of essential fatty acid deficiency

Male weanling rats were fed semipurified diets with and without essential fatty acid (EFA) and DDT (150 ppm) for 14 weeks to determine the effects of the pesticide on physiological and biochemical aspects of EFA deficiency (EFAD). DDT did not affect EFAD-induced reduction in growth rate or final body weight, nor did the pesticide affect EFAD-induced changes in feed efficiency or skin dermatitis. The pesticide did increase liver/body mass ratios, but did not interact with EFAD, which also increased this ratio. The pesticide produced complex changes in total fatty acid composition of liver and tail skin: liver levels of 18∶0, 18∶2 and 20∶3ω9 were increased, whereas levels of 12∶0, 14∶0 and 16∶0 were decreased. In both tissues, DDT interacted with EFA to increase 18∶2 levels. DDT did not change the total fatty acid 20∶3ω9/20∶4ω6 ratio in either tissue. In this study, although DDT did not exacerbate the physiological aspects of EFAD, DDT-induced changes in fatty acid composition of liver and tail skin indicated that 150 ppm DDT in the diets did alter lipid metabolism of the rats in an unexplained manner. Scientific contribution No. 811, Storrs Agricultural Experimental Station, University of Connecticut, Storrs, CT 06268.     

Glyceride structure variation in soybean varieties: II. Silver ion chromatographic analysis

The glyceride structures of 20 soybean varieties were determined by silver ion chromatography. Plots of the percentage of each triglyceride vs. the percentage of its constitutent fatty acids revealed no genetic variants that had not been found previously by stereospecific analysis. The results deviated significantly from the amounts predicted by the 1-random-2-random-3-random hypothesis of glyceride distribution. This deviation can be explained by a noncoincidence of the peak biosynthesis of oleic and linoleic acids during maturation of the beans. Journal Paper No. J-8840 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA. Project No. 2143. Abbreviations used: S=saturated acyl group on a triglyceride, 18∶0+16∶0. M=monounsaturated acyl group, 18∶1, D=diunsaturated acyl group, 18∶2. T=triunsaturated acyl group, 18∶3.     

FA composition of crude oil recovered from catfish viscera

The FA composition of crude catfish oil recovered from whole viscera, digestive tract, liver, gallbladder, and visceral storage fat was determined and compared with that of fillet and nugget (abdominal portion). About 34% crude fat (wet basis) could be recovered from the whole catfish viscera. FA found in crude catfish visceral oil were C14∶0, C16∶0, C16∶1, C18∶0, C18∶1, C18∶2, C18∶3, C20∶0, C20∶1, C20∶2, C20∶3, C20∶4, and C22∶6, the predominant FA being C18∶1, C16∶0, C18∶2, and C18∶0. Catfish visceral oil was characterized by a high level of unsaturated FA, which was similarly found in fillet and nugget. Total unsaturated FA in visceral oil amounted to 261.3 mg/g (dry basis) compared to that of fillet (259.3 mg/g) and nugget, (307.6 mg/g). The whole viscera contained 4.2 mg/g DHA compared to that of gallbladder (9.2 mg/g), fillet (9.3 mg/g), and nugget, (10.7 mg/g). The total n−3 FA in the whole and/or portioned visceral ranged from 4.3 to 20.9 mg/g.     

On the membrane phospholipids and their acyl group profiles of adrenal gland

The phospholipid composition and their acyl group profiles from subcellular fractions of guinea pig adrenal gland and the same fractions from the cortex and medulla of the bovine gland were compared. The phospholipids of guinea pig adrenal were enriched in diacyl-glycerophosphocholines (GPC) which comprised over 50% of the total phospholipids, but the proportions of ethanolamine and choline plasmalogens, sphingomyelin and diacyl-glycerophosphoserine (GPS) were lower in guinea pig adrenals as compared to the bovine adrenals. In the bovine adrenal, sphingomyelin and diacyl-GPS were enriched in the medulla, whereas diacyl-glycerophosphoinositol (GPI) were enriched in the cortex. Although lysolecithin was present (up to 4.5%) in the bovine adrenal, only trace amounts of this lipid were detected in the guinea pig adrenal. Characteristic acyl group profiles were found associated with each type of the phosphoglycerides in adrenal membranes. However, acyl group profiles of the phosphoglycerides were not greatly different either between the bovine and guinea pig adrenal or with respect to the type of subcellular membranes isolated. Diacyl-GPC were enriched in 16∶0 and 18∶1, but also contained considerable amounts of 18∶0, 18∶2 and 20∶4. Diacyl-GPE were enriched in 18∶0, 18∶1 and 20∶4, while diacyl-GPI, diacyl-GPS, as well as alkenylacyl-GPE, were enriched in 20∶4. The lysolecithin from bovine adrenal membranes contained mainly 16∶0, 18∶0 and 18∶1 with only trace amounts of the polyunsaturated fatty acids. Other polyunsaturated fatty acids, such as 22∶4 and 22∶6, are apparently not prominent in the phosphoglycerides from either the bovine or the guinea pig adrenal gland.     

Fatty acid patterns in iron-deficient maternal and neonatal rats

To determine the effects of maternal iron deficiency on lipid composition and fatty acid patterns in offspring, rats were fed ad libitum diets containing 5 ppm iron (deficient) (n=8) or 320 ppm iron (control) (n=7) and deionized water from day-1 of gestation through day-18 of lactation. On day-2 of lactation, litters were standardized to three male and three female pups. On day-18, pups were fasted for 4 hr before tissue and blood collection. Significant changes in serum and liver lipid concentrations and fatty acid patterns were observed in deficient pups. Serum triglycerides, cholesterol and phospholipids and liver triglycerides, cholesterol, and cholesteryl esters were increased. In deficient pups, percentage total fatty acids of 14∶0, 16∶1, 18∶1, 18∶2 from serum lipids were increased; in liver, 14∶0, 18∶2, 18∶3 were increased; 18∶0 and 20∶4 were decreased in both serum and liver. Dam serum lipid levels did not differ between groups. Lipid changes observed in iron-deficient pups did not consistently reflect the milk, serum or liver lipid patterns observed in dams. Altered lipid composition and fatty acid patterns of iron-deficient pups thus appear to be of endogenous origin.     

The identity of the cholesteryl esters in human milk

Milk samples were collected from 11 mothers who were at least 4 weeks postpartum. The amounts of fat and the fatty acid compositions of cholesteryl esters (CE) and triacylglycerols (TG) in the milk were determined. The mean concentration of total milk lipid was 3.01 gm/100 ml of milk±.42 SD. The major fatty acids esterified with CE and TG were 16∶0,cis 18∶1 and 18∶2. The patterns were similar except for a greater proportion ofcis 18∶1 in the CE. The majortrans fatty acid detected was the 18∶1 isomer which accounted for 4.48% of the TG fatty acids and 2.96% of the CE fatty acids. Scientific Contribution No. 821, Storrs Agricultural Experiment Station, University of Connecticu, Storrs, CT. 06268     

Molecular species composition of the major diacyl glycerophospholipids from muscle,liver, retina and brain of cod (Gadus morhua)

The molecular species composition of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) from white muscle, liver, retina and brain of cod (Gadus morhua) were determined by high-performance liquid chromatography of the respective 1,2-diacylglycerol 3,5-dinitrobenzoyl derivatives. A minimum of 69 diacyl species was identified. In muscle and liver saturated fatty acid/polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid/PUFA molecular species were predominant, particularly 16∶0/20∶5 and 16∶0/22∶6 in PC, 16∶0/22∶6 and 18∶1/22∶6 in PE and 18∶0/22∶6 and 18∶1/22∶6 in PS. Didocosahexaenoyl species were major components of PC, PE and PS from retina, comprising 29.3, 71.8 and 59.7% of the respective totals. Didocosahexaenoyl species were also abundant in PE and PS from brain, accounting for 13.8 and 24.0% of the totals, respectively. DiPUFA species were important in muscle, totalling 21.2% in PC and 38.3% in PE. PC from all tissues had the largest amounts of species containing only saturated or monounsaturated fatty acids, accounting for 59.8% of PC from brain, including 12.8% of 18∶1/24∶1 plus 24∶1/18∶1.     

Dietary fats rich in saturated fatty acids (12∶0, 14∶0, and 16∶0) enhance gallstone formation relative to monounsaturated fat (18∶1) in cholesterol-fed hamsters

To test the possibility that dietary palmitic acid (16∶0) may be lithogenic, different fats were blended to exchange 18∶1 in olive oil with either 16∶0 in palm stearin, 12∶0+14∶0 in coconut oil, or 14∶0+16∶0 in butterfat. Dietary 18∶2 was held constant at 1.2% energy (en) (with extra safflower oil as needed) in these four purified diets containing low fat (11% of total energy) and 0.4% cholesterol. A fifth, high-fat diet provided 40% of the total energy as the 16∶0-rich blend. All hamsters fed the low-fat, 16∶0-rich blend for six weeks developed cholesterol gallstones (8/8). Although the gallstone incidence was lower for the 12∶0+14∶0-rich diet (5/8), the severity of stone formation in affected hamsters was equal to that in the low-fat, 16∶0-rich group. Mucin accumulation in gallbladder bile was often associated with cholesterol gallstones in diets containing 16∶0, but was minimal in 18∶1-rich and 12∶0+14∶0-rich groups. Neither the lithogenic index (all>1.0), plasma lipids, nor liver cholesterol was a selective predictor of stone formation. The high-fat, 16∶0-rich diet actually decreased cholesterol stone incidence (3/8) and severity, but yielded a high incidence of pigment stones (5/8). Thus, saturated fat and 16∶0per se were not responsible for the exaggerated lithogenesis. Because the antilithogenic 18∶1-rich diet also normalized the 18∶2 intake (1.2% en) relative to previous butter diets (0.3% en), the potential importance of essential fatty acids (EFA) deficiency in the model was tested in a second study by feeding graded amounts of 18∶2 (0.3, 0.6, 0.9, and 1.2% en) as safflower oil in four low-fat, butter-rich diets (11% en as fat) without alleviating gallstone incidence or severity. These studies indicate that substitution of 18∶1 for saturated fatty acids in low-fat diets reduces gallstone formation without affecting the lithogenic index. Furthermore, intake of 18∶2 at or below the EFA requirement does not appear to be a major factor in this model.     

Phospholipid composition of the granular amebocyte from the horseshoe crab, Limulus polyphemus

The phospholipid composition was determined for the amebocyte of the primitive arthropod Limulus polyphemus. The total fatty acid composition of the cells' lipids was analyzed by gas chromatography/mass spectrometry (GC/MS) of fatty acid methyl esters (FAME). The FAME analysis revealed high levels of 20-carbon polyunsaturated fatty acids (PUFA), especially arachidonic (20∶4n-6) and eicosapentaenoic (20∶5n-3) acids. Almost 20% of the total lipid profile was comprised of dimethyl acetals of 16- to 20-carbon chain lengths, indicative of plasmalogens in the phospholipid pool. Phospholipids, analyzed by high-pressure liquid chromatography, included phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI), sphingomyelin (SPH), and cardiolipin (CL). PE and PC levels predominated at 42.2 and 36.3%, respectively. Smaller amounts of PS (9.0%) and PI (6.2%) were present, as well as low levels of SPH (4.6%), CL (1.6%), and trace amounts of lysophosphatidylcholine. The major phospholipid species, PE, PC, PS and PI, were collected and their molecular species were examined by electrospray-ionization mass spectrometry. The molecular species within the phospholipid classes reflected the high levels of PUFA seen in the total lipid profile. PI was mainly composed of 18∶0a/20∶4. Over half of the PS consisted of 18∶0a/18∶1 and 18∶0a/20∶4. The major PE species were 20∶1p/20∶5, 20∶1p/20∶4, 18∶0p/20∶5, and 18∶0p/20∶4. PC had the largest distribution of molecular species, and its most abundant species were 16∶0e/20∶5, 16∶0e/20∶4, and 16∶0p/20∶4. The presence of 16∶0e/20∶4 is the first documentation of a specific precursor to platelet-activating factor in an invertebrate hemocyte. Note: at the sn-1 position: [a=1=O-acyl, e=1-O-alkylether, and p=1-O-alk-1′-enyl (plasmalogen)].     

Molecular species composition of phosphatidylinositol from the brain,retina, liver and muscle of cod (Gadus morhua)

The molecular species composition of phosphatidylinositol (PI) purified from four different tissues from cod was found to show large tissue-specific differences. In brain 18∶0/20∶5 was the most abundant species (40.8%) followed by 18∶1/20∶5 (13.5%). In retina, 24–26% each of PI was the 16∶0/22∶6 and 18∶0/20∶4 species with 16–18% each of 18∶0/20∶5 and 18∶0/22∶6. In liver, almost half of the PI was 18∶0/20∶4 with 18% 18∶1/20∶4. In contrast, muscle contained almost 40% of 18∶0/22∶6 with 10–14% each of 18∶0/20∶4, 18∶0/20∶5 and 18∶1/22∶6. Molecular species are abbreviated as follows:e.g., 18∶0/20∶4 PI is 1-stearoyl-2-eicosatetraenoyl-sn-glycero-3-phosphoinositol.     

1-O-alk-1′-enyl-2-acyl-glycerophosphoethanolamine content and molecular species composition in fish brain

Ethanolamine glycerophospholipids from the brains of both trout and cod comprised 36–38% of 1-O-alk-1′-enyl-2-acyl-glycerophosphoethanolamine (GPE) determined using two methods. In 1-O-alk-1′-enyl-2-acyl-GPE from trout brain, the main molecular species were 18∶1a/18∶1, 18∶0a/18∶1 and 16∶0a/18∶1, which totalled 63.3%, while polyunsaturated fatty acid (PUFA) containing species totalled only 18.2%. 1-O-Alk-1′-enyl-2-acyl-GPE from cod brain was much more unsaturated with PUFA containing species totalling 52.6%, of which 18∶0a/20∶5n−3, 18∶1a/20∶5n−3 and 18∶1a/22∶6n−3 were predominant. In cod 18∶1a/18∶1, 18∶0a/18∶1 and 16∶0a/18∶1 were the only other species present at over 5% each, totalling 31.8%. In both cod and trout, small amounts of species containing 22∶4n−6 were found. The results of this and earlier studies indicate that there is considerable specificity of composition at the level of molecular species between different lipid classes and subclasses. Molecular species of 1-O-alk-1′-enyl-2-acyl-GPE are abbreviated as follows:e.g., 16∶0a/18∶1 GPE is 1-O-hexadec-1′-enyl-2-oleoyl-sn-glycero-3-phosphoethanolamine. The corresponding diacyl species, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine, is abbreviated as 16∶0/18∶1.     

Lipid composition of the pineal organ from rainbow trout (Oncorhynchus mykiss)

The lipid composition of the pineal organ from the rainbow trout (Oncorhynchus mykiss) was determined to establish whether the involvement of this organ in the control of circadian rhythms is reflected by specific adaptations of lipid composition. Lipid comprised 4.9% of the tissue wet weight and triacylglycerols were the major lipid class present (47% of total lipid). Phosphatidylcholine (PC) was the principal polar lipid, and smaller proportions of other phospholipids and cholesterol were also present. Plasmalogens contributed 11% of the ethanolamine glycerophospholipids (EGP). No cerebrosides were detected. The fatty acid composition of triacylglycerols was generally similar to that of total lipids in which saturated, monounsaturated and polyunsaturated fatty acids (PUFA) were present in almost equal proportions. Each of the polar lipid classes had a specific fatty acid composition. With the exception of phosphatidylinositol (PI), in which 20∶4n−6 comprised 27.4% of the total fatty acids, 22∶6n−3 was the principal PUFA in all lipid classes. The proportion of 20∶5n−3 never exceeded 6.0% of the fatty acids in any lipid class. The predominant molecular species of PC were 16∶0/22∶6n−3 and 16∶0/18∶1, which accounted for 33.2 and 28.5%, respectively, of the total molecular species of this phospholipid. Phosphatidylethanolamine (PE) contained the highest level of di-22∶6n−3 (13.0%) of any phospholipid. There was also 4.9% of this molecular species in phosphatidylserine (PS) and 4.1% in PC. In PE, the species 16∶0/22∶6, 18∶1/22∶6 and 18∶0/22∶6 totalled 45.1%, while in PS 18∶0/22∶6 accounted for 43.9% of the total molecular species. The most abundant molecular species of PI was 18∶0/20∶4n−6 (37.8%). The lipid composition of the pineal organ of trout, and particularly the molecular species composition of PI, is more similar to the composition of the retina than that of the brain. Molecular species are abbreviated as follows: e.g., 16∶0/22∶6 PC is 1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine.     

Changes in phosphatidylcholine molecular species in the shrimp <Emphasis Type="Italic">Macrobrachium borellii</Emphasis> in response to a water-soluble fraction of petroleum

The effect of the water-soluble fraction (WSF) of crude oil on lipid contents, lipid classes, FA, and PC molecular species was studied in high-phospholipid (hepatopancreas) and low-phospholipid (egg) tissues of a freshwater crustacean. After a 21-d exposure to a sublethal concentration of WSF, a significant decrease in shrimp total lipids was observed, although no alterations could be detected in the hepatopancreas or egg lipid contents. TAG/phospholipid ratios increased in the hepatopancreas and decreased in the eggs, suggesting alterations either in the mobilization of TAG to phospholipid pools or in the energy balance. The FA composition of phosphoglycerides in the hepatopancreas and eggs was dominated by PUFA, whereas the n−3/n−6 ratio was not affected by WSF exposure, although there was a significant increase in hepatopancreas 18∶1n−9. Analysis of the PC molecular species by HPLC-ELSD showed the presence of 15 species, with 16∶0/18∶1, 18∶1/18∶2, 16∶0/20∶5, and 16∶1/20∶5 being the major species in the hepatopancreas. The PC molecular species in the eggs showed a different pattern, dominated by 16∶0/18∶1 and 18∶1/18∶2. Of the PC molecular species, 10 contained 22∶6n−3, 20∶5n−3, and 20∶4n−6. Small amounts of di-PUFA species were also found. Exposure to WSF altered the PC molecular species in both tissues. The four major hepatopancreas molecular species and most of the ones containing PUFA decreased. This was compensated for by an increase in 16∶1/18∶1 (152%) and 18∶1/18∶1 (50%). The two major egg PC molecular species decreased, whereas the PUFA-containing ones increased. The contrasting responses of both tissues of WSF contamination suggests the presence of different homeostatic mechanisms.     

Egg yolk lipids and maternal diet in the nutrition of turkey embryo

Turkey hens were fed diets containing no added fat nor diets supplemented with soybean oil or neatsfoot oil. The composition of neutral and polar lipid fatty acids present in the unincubated turkey egg yolk was compared with that of those present in the yolk sac of the developing turkey embryo at different stages of development. Comparisons were made of the fatty acid fractions in the entire embryo homogenates, except liver and heart, which were analyzed separately. Changes in the relative amounts of the fatty acids are reported as affected by age of the embryo and by dietary lipids. The fatty acids from both the neutral and polar lipids which were utilized to the greatest extent for embryonic development were palmitoleic, oleic, linoleic, and linolenic, regardless of the dietary supplements. Arachidonic, tetracosenoic, and docosahexaenoic acids also were metabolized by the embryo. Saturated fatty acids, used by the embryo as development progressed, were palmitic, stearic, and arachidic acids. Analyses of the liver fatty acids showed that the C16∶0 C16∶1, C18∶0, C18∶1, and C20∶4 acids in the neutral and polar lipids decreased with embryonic development and varied with the type of diet. The heart contained low levels of myristic, palmitic, stearic, arachidic, and arachidonic acids in the neutral lipids and palmitoleic and oleic acids in the polar lipids.     

Liver subcellular fatty acid profiles of chicks fed diets containing hydrogenated fats and varying linoleate levels

Day-old male broiler chickens were fed semipurified diets containing 5% lipid from one of four different lipid sources: corn oil (CO), partially hydrogenated soybean oil (HSBO), a spent restaurant grease (SRG) and a purified mixture of triolein, tripalmitin and tristearin (OPS). Diets CO and HSBO contained adequate amounts of linoleic acid, but diets SRG and OPS were deficient in linoleate. In addition, SRG and HSBO containedtrans isomers of 16∶1 and 18∶1. The diets were fed for 3 wk to determine the effects of low linoleate levels andtrans isomers on fatty acid profiles in liver microsomes, mitochondria and cytosol. Chicks fed HSBO had the highest body weights, while those fed SRG and OPS had the lowest. The incidence and severity of dermatitis were similar for all treatments. The proportions of linoleate and arachidonate in lipids from liver subcecullar fractions were reduced significantly in chicks fed OPS and SRG; however levels of 20∶3ω9 were not increased. Feeding HSBO, which is high in both linoleate and linolenate, resulted in higher levels of 18∶3ω3 and 20∶5ω3 in liver subcellular fractions and lower levels of 20∶4ω6 than those seen in chicks fed CO. The isomeric forms of 18∶1 present in the partially hydrogenated fats (HSBO and SRG) appeared to be incorporated into the lipids of liver fractions. The results of this study show that dietary lipids influence fatty acid, profiles of chick liver microsomes, mitochondria and cytosol. Decreases in linoleate and arachidonate in these organelles occur before overt essential fatty acid (EFA) deficiency signs in chicks fed EFA-deficient diets. Published as Scientific Paper No. 7512, College of Agriculture and Home Economics Research Center, Project No. 4723, Washington State University, Pullman, WA.     

Comparison of body weight and adipose tissue in male C57BI/6J mice fed diets with and withouttrans fatty acids

The effect of a diet containingtrans-fatty acids (tFA) on the fatty acid composition and fat accumulation in adipose tissue was investigated in mice. Male C57BI/6J mice were fed Control or Trans Diets that were similar, except that 50% of the 18∶1, which was allcis in the Control Diet, was replaced bytFA in the Trans Diet. At selected ages, body weight, epididymal fat pad weight, perirenal fat yield, adipose tissue cellularity and fatty acid composition were examined. Over the time period studied (2–24 mon), the proportion of 18∶0 and 16∶0 tended to decrease whilecis-18∶1 levels increased. Compared to the Control Diet, the Trans Diet resulted in adipose tissue lipids with higher percentages of 14∶0 and 18∶2n−6 and lower percentages ofcis-18∶1 and 20∶4n−6. In polar lipids,tFA replaced saturated fatty acids, whereastFA replacedcis-18∶1 in the nonpolar lipids. Body weights at 16 and 24 mon of age and epididymal fat pad weights at 8–24 mon of age were lower in mice fed the Trans Diet as compared to those fed the Control Diet. At the ages studied, the Trans Diet also resulted in lower values for perirenal fat weights, triacylglycerol to polar lipid ratios, and adipose cell size. The data suggest that chronic consumption oftFA affects lipid metabolism and results in decreased fat accumulation in murine adipose tissue.     

The acyl and Alk-1-enyl groups of the major phosphoglycerides from ox brain myelin and mouse brain microsomal,mitochondrial and myelin fractions

The major phosphoglycerides from ox brain myelin and mouse brain microsomal, mitochondrial and myelin fractions were separated by preparative thin layer chromatography. Alk-1-enyl groups from the alk-1-enyl acyl glycerophosphorylethanolamines were reacted with 1,3-propanediol to form the 1,3-dioxolane derivatives. Acyl groups were converted to the methyl ester derivatives and the acyl groups from alk-1-enyl acyl glycerophosphorylethanolamines and diacyl glycerophosphorylethanolamines were also determined separately. The acyl and alk-1-enyl group compositions of the phosphoglycerides from microsomal and mitochondrial fractions were quite similar. The ethanolamine and serine phosphoglycerides contained large amounts of 18∶0, 18∶1, 20∶4 and 22∶6 acyl groups. The choline phosphoglycerides had small amounts of polyunsaturated acyl groups and large amounts of 16∶0, 18∶1 and 18∶0 acyl groups. The mitochondrial cardiolipins contained unusual amounts of several acyl groups including 18∶1, 52%; 18∶2, 6%; and 16.1, 4%. A large portion of the mouse brain 18∶2 is in that fraction. The myelin phosphoglycerides were deficient in saturated and 22∶6 groups and markedly enriched in 18∶1 and 20∶1 groups when compared with the corresponding microsomal or mitochondrial phosphoglycerides. Presented in part at the AOCS Meetings, New York, October 1968 and San Francisco, April 1969.     

A comparison of the oleaginous yeast,Candida curvata,grown on different carbon sources in continuous and batch culture

The oleaginous yeast,Candida curvata D, was grown in both batch and continuous culture on 5 different carbon sources to compare the efficiency of fat production from the various substrates. Maximum lipid accumulation occurred in batch culture with xylose as the carbon source on nitrogenlimited medium reaching a level of 49% (w/w) of the biomass, but this was reduced to 37% at the optimum dilution rate (D=0.05/hr) in a chemostat. Both the highest biomass and lipid yields were attained in continuous culture with lactose as the sole carbon source at a dilution rate of D=0.04/hr, giving an efficiency of substrate conversion of 60 g of biomass and 18.6 g lipid per 100 g lactose utilized. The relative proportions of the major fatty acids (16∶0, 18∶0, 18∶1, 18∶2) in the lipid were found to vary considerably in batch culture and in continuous culture under carbon-limited conditions. However, on nitrogen-limited media in the chemostat, the fatty acid composition remained relatively constant over the whole range of dilution rates employed. Lipid from xylose-grown cells contained the greatest percentage of stearic acid (18∶0) 15% and the lowest linoleic acid (18∶2) 4%, whereas lipid from ethanol-grown cells contained elevated levels of oleic acid (18∶1) 51% and decreased palmitic acid (16∶0) 25%.     

Differences in the long chain (sphingoid) base composition of sphingomyelin from rats bearing Morris hepatoma 7777

The long chain bases of sphingomyelin from Morris hepatoma 7777 and host and control livers were analyzed by capillary gas liquid chromatography. Sphingosine (18∶1) was the major long chain base of control livers (66.5%) and hepatomas (65.6%), but hepatomas also had a high percentage (9.3 vs 4.4) of the 16∶1 homolog. Host liver had the most unusual long chain base composition, with ca. equal 16∶1 (24.4%) and 18∶1 (21.4%) and high amounts of 20-carbon bases (9.2% 20∶0 and 15.3% 20∶1). These differences may be related to the aberrant fatty acid metabolism known to occur in tumor-bearing animals. Such large perturbations in the long chain base composition of hepatic sphingomyelin are unprecedented and could have a major impact on the properties of host membranes.