Synthesis of lipids from acetate by human preputial and abdominal skin in vitro

Lipogenesis in vitro from acetate-1-(14)C was studied in human preputial skin and abdominal skin. Radioactive lipids were separated by column chromatography on Florisil and by thin-layer chromatography on silica gel. Radioactivity was incorporated chiefly into the triglyceride, sterol, and polar lipid fractions, while lesser amounts of (14)C were found in the hydrocarbon, wax, diglyceride, monoglyceride, and fatty acid fractions; labeling of steryl esters was minimal. On thin-layer chromatography, the radioactive polar lipids had mobilities similar to lysolecithin, phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidic acid. The radioactive fatty acids of the different lipid fractions were separated by gas-liquid chromatography. The major (14)C-labeled acids were 16:0 and 18:0. Radioactivity was also detected in acids 14:0, 15:0, 16:1, 18:1, 18:2, 20:0, 20:1, 22:0, 24:0, 24:1, and 26:0. No radioactivity could be detected in arachidonic acid, although this fatty acid comprises 9% of the chromatographed fatty acids. The pattern of incorporated (14)C was different from the percentage mass composition of the fatty acids. Skin is therefore active in the biosynthesis of a wider variety of lipids than previously demonstrated.     

Die Lipide von Endomycopsis vernalis bei verschiedener Stickstoff-Ernährung

1. Endomycopsis vernalis was cultivated on media with different N supply: series A 1%, series B 0,125% asparagine. Sonified cells were extracted and yielded 14.3% (A) and 65.3 (B) total lipids/non lipid dry matter respectively.
2. Neutral and complex lipids were separated by rubber membrane dialysis. There is no difference in the percentage of complex lipids of both series. The increase of lipids in cells grown on low N level is due to a higher content of neutral lipids.
3. Components of the neutral lipids, analysed by DC, were diglycerides, triglycerides, free and esterified ergosterol. Their percentage is influenced by the nutritional conditions. There is a significant increase of triglycerides and of sterol esters in the high lipid cells of series B.
4. Methyl esters of component fatty acids of glycerides and sterol esters were analyzed by GLC. Saturated acids C₁₄, C₁₅, C₁₆, C₁₇, C₁₈, monoenic acids C₁₆ and C₁₈, linoleic and linolenic acids were found to be present. Major acids were in all cases 18:1 (17–57%), 18:2 (18–50%) and 16:0 (10–18%). Linolenic acid is higher in di-and triglycerides of low lipid cells of series A than in high lipid cells of series B. Both qualitative and quantitative differences of fatty acids were found in sterol esters of series A and B respectively.
5. The major components of complex lipids, identified by DC and isolated by CC, in both series, were phosphatidyl choline (A:36.5, B:41.0%) and phosphatidyl ethanolamine (A:24.9, B:20.5%) in addition to small amounts of lysophosphatidyl choline, lysophosphatidyl ethanolamine, phosphatidyl serine, monophosphoinositide, diphosphatidyl glycerol and, possibly cerebroside like substances.
6. Methyl esters of the fatty acids of phosphatidyl choline and ethanolamine from both series were determined by GLC. In all samples 16:0, 18:0, 18:1, 18:2 and 18:3 acids were present besides of traces of 16:1 and 17:0. In contrast to neutral lipids the major acid of phospholipids is linoleic (53–58%), followed by oleic (8–24%) and linolenic acid (1–18%). The percentages of palmitic (4–8%) and stearic acids (tr.-1%) are small. Low lipid cells of series A differ from high lipid cells of series B by an increase of linolenic, and a decrease of linoleic acids, both in phosphatidyl choline and phosphatidyl ethanolamine.

     

Effect of Retinol on Liver Lipid Metabolism of Rats

Effect of feeding 4.23, 16.94 and 27.53 mg of retinol daily for 10 days on the liver lipids of adult rats has been studied. Feeding of different amounts of retinol produced dose dependent toxicity symptoms in rats. Retinol feeding resulted in significant elevations of liver total lipids, total fatty acids, and glycerides, The amounts of liver esterified cholesterol were significantly raised in rats fed different amounts of retinol. Acetate-1-¹⁴C incorporation was increased in liver total cholesterol of rats fed 27.53 mg retinol and in free cholesterol of all retinol fed rats. Total ¹⁴C activity of hepatic triglycerides of retinol fed rats was the same as that of control, but their specific activity was decreased. Significant alterations were noted in phosphatidyl serine, lysophosphatidyl choline, lysophosphatidyl ethanolamine, sphingomyelin, phosphatidyl choline, phosphatidyl ethanolamine and phosphatidic acid and polyglycerophosphate fractions in liver rats fed different amounts of retinol.     

Comparative studies on lipid metabolism in various salt transporting organs of the European eel (Anguilla anguilla). Mono-unsaturated phosphatidylethanolamine as a key substance

1. Incorporation in vivo into tissue lipids of (1-14C)acetate added to the water in the incubation tank showed the same relative distribution pattern of 14C-activity among various phospholipids in the gills, the esophagus and the intestine, when the eel was incubated in sea-water; in fresh water this pattern was found only in the intestine, while both the gills and the esophagus showed a relative excess of 14C-label in phosphatidylethanolamine (PE). 2. Similar studies with (32P)phosphate also showed a relative excess of (32P)PE in both the gills and esophagus in fresh water compared to sea-water, and no such difference in the intestine. 3. As long as the labelled precursors were added to the water in the incubation tank both (14C)PE and (32P)PE were not identical to unlabelled PE on thin-layer chromatograms, and the 14C-labelled lipids contained predominantly C16:1 and C18:1 fatty acids. 4. However, when the two precursors were injected directly into the eel there was no longer any marked difference between the distribution patterns of radioactivity among gill phospholipids in fresh water and sea-water; there was no longer any difference between labelled and unlabelled PE on thin-layer chromatograms, and the 14C-labelled gill lipids contained predominantly C16:0 and C18:0 fatty acids. 5. The corresponding liver lipids were affected neither by a change in environmental salinity nor in precursor application.     

Studies on cartilage formation. XVI. Chemical and histochemical assay of lipids in the regenerating articular cartilage.

The articular surface of the distal part of the femur was removed operatively in dogs, and the regenerating articular surface and the GTC were investigated at different stages from the 7th to the 70th postoperative days. During this period cartilage islets arose in the GTAS, while the GTC transformed to connective tissue. At 7 days the lipid content of the tissue was markedly higher than at the other stages studied. Lipids, predominantly triglycerides, were present in extracellular form as well. From the 20th to the 70th day the PL fraction became predominant and, in addition to the pre-existing lecithin, relatively large quantities of lysolecithin, sphingomyelin, phosphatidyl-ethanolamine, phosphatidyl-serine and phosphatidyl-inositol could be gradually demonstrated. Differences were noted in the time of appearance and binding of PLs between the two types of granulation tissue. As time proceeded, the proportion of saturated fatty acids decreased in favour of unsaturated ones. At 70 days, the GTAS contained fatty acids up to C18. About 50% of the fatty acids consisted of C16:1, C18:2 and C18:1. At the same stage, in the GTC C16:1, C18:1 and C20:1 were present in larger amounts. Of the free fatty acids C16:1, C16 and C18 were in predominance in the GTAS and the proportion of fatty acids having more then one double bonds increased with time. In the GTC C16 and C18:1 were in great majority. According to histochemical evidence, the tissues did not contain extracellular lipids from the 20th postoperative day. In the cells, the presence of glycerides, PLs, lipoproteins and cholesterol was demonstrated. In addition, in cartilage precursors of more advanced maturity, a considerable fatty acid positivity was noted.     

Lipids and fatty acids of the southwestern corn borer,Diatraea grandiosella

The lipids of the adults and of several immature stages of the southwestern corn borer, Diatraea grandiosella, were studied after they were fed natural corn stalks or artificial diets. Linoleic acid (18:2) was the major fatty acid of the neutral lipids in both the natural and the artificial diets, but aleic acid (18:1) was the principal neutral lipid in all insect stages. Also, linoleic acid and oleic acid were the principal acids in the insect phospholipids of all stages. The content of linoleic acid in the natural diet was also high, but that in the artificial diet appeared to be much too low for insect requirements. Phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE) were the major phospholipids in all growth stages. Thus, in larvae diapausing in the field, the unsaturated fatty acid content of PC was 59·3 per cent, primarily 16:1 and 18:1, and PE was 87·4 per cent, primarily 18:1, 18:2, and 18:3, and the fatty acids in the number 1- and 2-positions of PC were 53·6 and 97·2 per cent unsaturated, respectively. The haemolymph of diapausing southwestern corn borer larvae contained primarily glycerides but also had some PC and PE. Fat body from diapausing larvae contained primarily 16:0, 16:1, and 18:1 in a ratio of 1 : 1 : 2. Thus lipids of the southwestern corn borer do not reflect dietary lipids as closely as do other insects studied.     

Nature of DNA-bound fatty acids in Pseudomonas aurantiaca

The existence of Pseudomonas aurantiaca DNA-bound fatty acids and lipids is presented in this work. The isolation of DNA was carried out by two different procedures, namely, phenol and detergent-based phenol isolation in order to prove the presence of DNA-bound lipids. The lipid content of DNA is expressed in terms of fatty acid profile. A high level of 16:0, 18:0 and 18:1 is characteristic for tightly bound DNA lipids. On the other hand, the fatty acids such as 14:1, iso14:0 and iso16:0 are found in trace amounts only in DNA lipid fraction, but these fatty acids are not found in the whole-cell lipids. Absolutely no 3-hydroxy fatty acids were found in DNA lipids. However, both C16 and C18 species represent the main fatty acids of whole-cell and DNA-bound lipids. The presence of DNA-bound lipids even under tough treatment of DNA allows to conclude that these lipids represent a special pool among cellular lipids.     

Changes in the lipid and fatty acid composition of hemolymph and ovaries during the reproductive cycle of Labidura riparia

Lipid metabolism was investigated during the reproductive cycle of Labidura riparia (Pallas). The lipid classes and their constitutive fatty acids present in hemolymph and ovaries were measured using thin‐layer chromatography and gas‐liquid chromatography. In the hemolymph, total lipids increase steadily from the previtellogenic period to vitellogenic arrest. These lipids are predominantly diacylglycerols and phospholipids. In the ovaries, total lipids increase during vitellogenesis then decrease during the vitellogenesis arrest period. The major lipids are triacylglycerols, followed by phospholipids. In both hemolymph and ovaries, all lipid classes contained variable proportions of seven main fatty acids: the saturated fatty acids myristic acid (14:0), palmetic acid (16:0), and stearic acid (18:0); the monounsaturated fatty acids palmitoleic acid (16:1) and oleic acid (18:1); and the polyunsaturated fatty acids linoleic acid (18:2) and linolenic acid (18:3). Unsaturated fatty acids predominate throughout the reproductive cycle. The percentage compositions of total and triacylglycerol fatty acids do not change markedly during the reproductive cycle in hemolymph nor in ovaries, with 18:2, 18:1 and 16:0 fatty acids being the major components. However, for diacylglycerols and phospholipids, the proportions of fatty acids vary systematically. For phospholipids during the vitellogenesis period, 18:2 increases considerably whereas other fatty acids decrease; for diacylglycerols, these fatty acids vary in the reverse way.     

Lipids and Lipoprotein Complex in Photosynthetic Tissues

The lipids and pigments of corn and soybean leaves grown in light and in dark were examined. The green leaf contained appreciably greater amounts of the two galactolipids, sulfolipid, phosphatidyl glycerol and diphosphatidyl glycerol, while the etiolated leaf had relatively more cerebroside, sterol glucoside, phosphatidyl ethanolamine and lecithin. The prominent component of glycerides was 1,2-diglyceride in green leaf, and triglyceride in etiolated leaf. The green leaf lipids showed a remarkable specificity of component fatty acids, but those of etiolated leaf only at lower rate. From the results, possible functions of the lipids were discussed.     

Lipids and fatty acids of the mussel (Mytilus Platensis d'Orbigny) from South Atlantic waters

The lipid composition of the common mussel (Mytilus platensis d'Orbigny), which lives on littoral beds along the coast of Buenos Aires province, Argentina, was studied. The main non-polar lipids were triacylglycerols, while phosphatidyl choline and phosphatidyl ethanlamine were the main phospholipids. The predominant fatty acids were 16:0,16:1ω7, 18:0, 18:1ω9, 20:5ω3 and 22:6ω3. The content of polyenoic acids of 20 and 22 carbons increased and 16:0 + 16:1ω7 acids decreased in spring-summer together with an increase in non-polar lipids. Sexual maturation modified the lipid composition of gametes. By the end of the gonad development, a considerable increase of gonadal lipids and polyenoic fatty acids of 20 and 22 carbons was observed.     

RADIOLABELING STUDIES OF LIPIDS AND FATTY ACIDS IN NANNOCHLOROPSIS (EUSTIGMATOPHYCEAE), AN OLEAGINOUS MARINE ALGA1

The synthesis of fatty acids and lipids in Nannochloropsis sp. was investigated by labeling cells in vivo with [¹⁴C]-bicarbonate or [¹⁴C]-acetate. [¹⁴C]-bicarbonate was incorporated to the greatest extent into 16:0, 16:1, and 14:0 fatty acids, which are the predominant fatty acids of triacylglycerols. However, more than half of the [¹⁴C]-acetate was incorporated into longer and more desaturated fatty acids, which are constituents of membrane lipids. [¹⁴C]-acetate was incorporated most strongly into phosphatidylcholine, which rapidly lost label during a 5-h chase period. The label associated with phosphatidylethanolamine also decreased during the chase period, whereas label in other membrane lipids and triacylglycerol increased. The dynamics of labeling, along with information regarding the acyl compositions of various lipids, suggests that 1) the primary products of chloroplast fatty acid synthesis are 14:0, 16:0, and 16:1; 2) C₂₀ fatty acids are formed by an elongation reaction that can utilize externally supplied acetate; 3) phosphatidylcholine is a site for desaturation of C₁₈ fatty acids; and 4) phosphatidylethanolamine may be a site for desaturation of C₂₀ fatty acids.     

Lipids of saprophytic bacteria produced during growth on a complex organic substrate

The composition of lipids and the structure of mycolic acids were studied in Mycobacterium lacticolum var. aliphaticum isolated from soil and grown on MPB. The lipids of all strains were found to contain phosphatidyl inositol mannosides, phosphatidyl ethanolamine, cardiolipin, mycolic and common fatty acids, triglycerides, wax, and several unidentified compounds. The structure of mycolic acids was established by mass spectrometry. The mycolic acids C34:0, C35:0 and C36:0 prevailed in strain 175, and the mycolic acids C34:1, C34:0, C36:1 and C36:0 predominated in strain 180. The composition of minor components was assayed. Variations in the composition of mycolic acids depending on the source of carbon in the medium are discussed.     

Floral Lipid Chemistry of Byrsonima crassifolia (Malpigheaceae) and a Use of Floral Lipids by Centris Bees (Hymenoptera: Apidae)

Byrsonima rrassifolia (L.), a Neotropical malpighiaceous tree or treelet, has flowers that produce abundant lipids instead of nectar. Several species of Centris bees collect this oil. The floral oil shows variation between trees and can be separated into two types. One type is most common (11 of 14 samples) and consists of mono- and di-glycerides, some free fatty acids, a small amount of tri-glycerides and a trace of carbohydrate. The composition of the glycerides is predominantly (53–63%) esters of unsaturated 18C–22C fatty acids with the rest made up of 14C–18C saturated fatty acids. The second type of floral oil is similar to type one except that the samples contain large amounts of an unknown lipid more polar than the standards. Oil collected from the scopae of two representative Centris species, C. adanae and C. flavofasciata, was the same as the type one oil collected from B. rrassifolia floral elaiophores. The liquid provisions from the cells of several groundnesting Centris species was also found to be identical to B. crassifolia type one floral elaiophore oil with the exception of several minor ninhydrin positive compounds which may have been derived from the pollen which makes up part of the larval food provisions.     

Lipids from nerve tissues of the horseshoe crab, Limulus polyphemus.

1. The predominant lipids of nerve cords, ganglion and brain from horseshoe crabs were cholesterol (11% of lipid) and phospholipid (81% of lipid). 2. Major phospholipids were phosphatidyl ethanolamine and phosphatidyl choline with lesser amounts of phosphatidyl serine and phosphatidyl inositol and sphingomyelin. 3. The phospholipid fraction was characterized by a high content of plasmalogen, i.e. alk-1-enyl acyl phosphatides, so that 42% of the ethanolamine phosphatides were the plasmalogen, phosphatidal ethanolamine. 4. Phosphatidyl choline and phosphatidyl ethanolamine were high in polyunsaturation with 20:4 and 20:5 major fatty acids. Sphingomyelin had predominantly long chain saturated fatty acids. 5. Cerebrosides and gangliosides, which are associated with vertebrate nerve tissues, were absent from nerves of horseshoe crabs.     

Synthesis of fatty acids from [1-14C]acetylcoenzyme A in subcellular particles of rat epididymal adipose tissue

1. Mitochondrial and microsomal fractions of rat epididymal adipose tissue incorporated [1-(14)C]acetyl-CoA equally well into various fatty acids by a chain-elongation mechanism. C(18) and C(20) fatty acids were the two major products, and comprised about 80% of the total fatty acids synthesized in both particles. 2. When incubated in air, mitochondria synthesized stearic acid, octadecenoic acid and eicosamonoenoic acid in almost equal amounts (about 20% each), whereas in microsomal fractions, the synthesis of octadecenoic acid was more than fivefold the stearic acid formation. In both fractions, major components of synthesized monoenoic fatty acids were the Delta(11:12) isomers. Hexadecenoic acid and octadecenoic acid from whole adipose tissue contained approx. 11 and 14% of the Delta(11:12) isomer respectively. 3. When mitochondria or microsomal fractions were incubated in nitrogen, there was increased synthesis of stearic acid and palmitic acid and less of C(16) and C(18) monoenoic acids; synthesis of C(20) acids remained predominantly of the monoenoic acids. Determination of the position of the double bond in the monoenoic acids supported the view that the synthesis of hexadecenoic acid and octadecenoic acid involves a desaturase activity, whereas eicosamonoenoic acid and eicosadienoic acid are formed only by elongation of endogenous fatty acids. 4. Most of the radioactivity was found in free fatty acids (63%) and the phospholipid (26%) fraction. In phospholipids, phosphatidylcholine and phosphatidylethanolamine were the two major components. 5. Most of the fatty acids synthesized, including those not normally found in particle lipids (arachidic acid, eicosamonoenoic acid and eicosadienoic acid) were distributed fairly evenly in the phospholipid and free fatty acid fractions. However, stearic acid was found predominantly in the phospholipid fraction.     

Dependence of the fatty acid composition of the lipids in fungi of the genus Penicillium on their natural habitat conditions

The fatty acid composition of lipids was studied in Penicillium fungi growing in different habitats. Saturated fatty acids were represented by lauric, margaric, stearic and palmitic acids (the latter prevailed-- 18%-26%). Unsaturated monoene fatty acids were represented by acids from C16:1 to C18:1, diene and triene fatty acids by linoleic and linolenic acids. The predominance of linoleic acid was not found in all cultures of the genus. Changes in the fatty acid composition of lipids may be attributed to different ecological habitats of the Penicillium genus species.     

Culture age and carbamoylcholine increase the incorporation of endogenously synthesized linoleic acid in lipids of Trypanosoma cruzi epimastigotes

Physiological and cellular adaptations to environmental changes are known to be related to modifications in membrane lipids. This work provides metabolic and compositional evidence that Trypanosoma cruzi epimastigotes are able to synthesize and desaturate fatty acids, to incorporate them into their lipids, and to modify this incorporation when carbamoylcholine is present in the medium. The fatty acids formed from [2-(14)C]acetate in the period from 2 to 9 days were mostly (70%) incorporated in phospholipids, the remainder 30% being recovered in neutral lipids, such as triacylglycerols (TAG) and diacylglycerols (DAG). The main fatty acids formed from [2-(14)C]acetate were saturates (16:0, 18:0), monoenes (16:1, 18:1) and dienes (mostly 18:2). The ratios between labelled unsaturated and saturated fatty acids increased continuously with growth, consistent with a precursor-product relationship between the main fatty acids, and with the occurrence in T. cruzi of Delta(9)- and Delta(12)-desaturases. From days 2 to 5, [(14)C]18:2 was the main fatty acid produced. Accordingly, the fatty acid profiles showed a significant increase in the percentage of 18:2 in all lipids in the period under study, especially in the first 2 to 5 days. In the presence of carbamoylcholine, the labelling of DAG and TAG with [(14)C]18:2 augmented. The results indicate that T cruzi is able to synthesize the main types of fatty acids required to form its membrane lipids, and to exchange them actively in response to environmental stimuli.     

Lipids of Chlamydomonas reinhardi under different growth conditions

Photo-, mixo- and heterotrophically grown cultures of Chlamydomonas reinhardi (wild type ss and 2 streptomycin-resistant mutants sr₃ and sr₃₅) have been analyzed for lipids and fatty acids. Ether-soluble lipids, chlorophyll, monogalactosyl diglyceride, digalactosyl diglyceride, sulfolipid, phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl glycerol and the relative amounts of fatty acids in total and individual lipids have been determined. The lipid and fatty acid compositions are very similar in the 3 strains and are not affected by the mutations. Fatty acids belong exclusively to the C₁₆ and C₁₈ series, 16:0, 16:4, 18:1, 18:2, 18:3 (6,9,12) and 18:3 (9,12,15) comprising about 90% of the total. 18:3 (6,9,12) is concentrated in phosphatidyl ethanolamine. In streptomycin-bleached sr₃ cells, ether-soluble lipids increase from 7 to 11% of dry weight on greening, mostly due to synthesis of monogalactosyl diglyceride and chlorophyll. Monogalactosyl diglyceride of bleached cells exhibits the same fatty acid pattern before and after greening.     

Occurrence of long-chain fatty acids and glycolipids in the cell-envelope fractions of baker''s yeast

1. The total yield of fatty acids from the whole envelopes was markedly higher than that obtained from the ordinary cell walls. In both samples the major fatty acids were C(16) and C(18) acids. 2. The whole envelopes contained C(18) acids and long-chain (C(19)-C(26)) fatty acids, in a higher proportion than did the ordinary cell walls. Fifteen fatty acids with more than 18 carbon atoms were identified, among which 2-hydroxy-C(26:0) and C(26:0) acids predominated. 3. A complex sphingolipid containing inositol, phosphorus and mannose was isolated from the whole cell envelopes. The main fatty acids of this lipid were 2-hydroxy-C(26:0) and C(26:0) acids. It was concluded that this sphingolipid is present both in the ordinary cell wall and in the plasma membrane of baker's yeast. 4. The neutral lipids amounted to over 50% and the glycerophosphatides to about 30% of the total fatty acid content of the whole envelope. The major fatty acids in these lipids were C(16:1), C(18:1) and C(16:0) acids. The proportion of fatty acids with more than 18 carbon atoms was lowest in the neutral lipids, whereas the neutral glycolipids contained the highest percentage of these fatty acids. Acidic glycolipids amounted to 14% of the total fatty acid content of the whole envelope. The presence of a cerebroside sulphate in this lipid fraction was demonstrated, whereas the high content of 2-hydroxy-C(26:0) acid found is caused by the complex inositol- and mannose-containing sphingolipid.     

LIPID COMPOSITION OF HUMAN, BOVINE AND SHEEP PINEAL GLANDS

Abstract— —The lipid composition of human, bovine and sheep pineal glands was determined. No characteristic species difference was found in lipid content and composition. The total lipid was 2·9–4·0 per cent of wet weight of which phospholipid comprised 58–71 per cent and cholesterol 13·9–15·8 per cent in the three species. The phospholipid composition was 45 per cent phosphatidyl choline, 22 per cent phosphatidyl ethanolamine, 14 per cent sphingomyelin, 9 per cent phosphatidyl serine, 8 per cent monophosphoinositide, and 2 per cent diphosphatidyl glycerol. The major fatty acids found were C14:0, C16:0, C18:0, C16:1, and C18:1. In contrast to other tissues, pineal sphingomyelin has a low C24:1 content. No significant amounts of polyphosphoinositides or gangliosides were detected. When its lipid composition is compared with that of a number of other tissues, pineal is found to be most similar to testes and unlike pituitary and brain.