Occurrence of steryl and wax esters in Dicranum elongatum

The steryl and wax esters of the frozen subarctic moss Dicranum elongatum Schleich contained fatty acids 39.8 mg per gram dry green tissue. The content decreased with increasing age of the moss shoots, but no great changes were found in the fatty acid pattern of the esters. The major part of the steryl and wax ester fraction of the green shoots was made up of esterified sterols (85%), and the rest (15%) of esterified aliphatic alcohols. No great changes were found in their relative proportions with increased age of the shoots. Some changes were evident in the pattern of individual esterified sterols, however. The proportion of cycloartenol was lower in the older parts than in the green part, and the proportion of campesterol, stigmasterol, and β-sitosterol were lower in the green part. The major esterified aliphatic alcohols were 1-octadecanol, phytol and geranylgeraniol. The proportion of geranylgeraniol was highest in the green part and that of phytol in the older parts. The main alcohol of the surface lipids was 1-octadecanol.     

Separation and analysis of steryl and wax esters from Dicranum elongatum

Abstract Complete separation of the steryl and wax esters in the subarctic moss Dicranum elongatum was achieved on MgO thin-layer plates without any notable alteration of the acyl and alkyl moieties of the esters. Gas chromatography-mass spectrometry of the hydrolyzed fraction showed that the sterols (campesterol, stigmasterol, sitosterol, cycloartenol, 24-methylene cycloartanol and an unidentified sterol) were primarily esterified with unsaturated fatty acids 18:2 ω 6, 18:3 ω 3 and 20:4 ω 6. In contrast, the wax alcohols (l-octadecanol, phytol and geranylgeraniol) were mainly esterified with saturated fatty acids with 16:0, 18:0 and 20:0 as major components. No great differences were found in the fatty acid pattern of the steryl esters between different portions of the shoot. Slight differences, however, were found in the proportions of ω 3 and ω 6 fatty acids. In the wax esters a clear decrease was found in the proportions of 18:0 and 20:0 acids with increased shoot age accompanied by a slight increase in the proportions of 14:0, 20:4 ω 6 and phytenic acid.     

Fatty acid and sterol specificity in the biosynthesis of steryl esters by enzyme preparations from spinach leaves

Acetone powders prepared from the 20,000g participate fraction of spinach (Spinacia oleracea L.) leaves catalyzed the formation of steryl esters from free sterol and 1,2-diacylglycerol as the acyl donor. There was no sterol specificity when cholesterol, sitosterol, and campesterol were compared. When rates of sterol ester biosynthesis were compared using different 1,2-diacylglycerols it was found that the shorter chain fatty acids and the more unsaturated fatty acids were preferred. When the substrate concentration of diacylglycerol was varied, the maximal velocities obtained with the different substrates were dipalmitoleoyl- >dilinolenoyl- >dioleoyl- >dilinoleoyl-glycerol. It was demonstrated by silver nitrate thin-layer chromatography that the fatty acids of the supplied diacylglycerols were transferred to the sterol. When diacylglycerol mixtures were supplied, it was found that unsaturated diacylglycerols greatly stimulated conversion of saturated diacylglycerols to saturated steryl esters. For an equimolar mixture of dipalmitoyl-, dioleoyl-, dilinoleoyl-, and dilinolenoyl-glycerol, about equal amounts of the four steryl ester species were synthesized.     

Content and Fatty Acid Composition of Steryl and Wax Esters in Germinating Spores of Polytrichum commune

Polytrichum commune spores contained 5.61 ± 0.52 mg steryl and wax esters, including volatile compounds, per 100 mg dry weight of spores. Volatile compounds were not found in 3-h-old sporelings. The content of the steryl and wax ester fraction, excluding the volatile compounds, is slightly increased during the first 6 h of germination. Thereafter, the content is decreased throughout the germination. Thus, 3-day-old sporelings contained 0.52 ± 0.05 mg steryl and wax esters per 100 mg dry weight of spores. In connection with protonema growth, steryl and wax esters were produced, and the 7-day-old cultures contained 5.09 ± 0.37 mg steryl and wax esters per 100 mg dry weight of spores. The main fatty acids of the steryl and wax ester fraction of dry spores and germinating spores as well as of protonemata were palmitic, oleic, linoleic and linolenic acids. Polyunsaturated C 20 acids were present only in trace or small amounts. Phytanic and phytenic acids were found in small amounts in dry spores, in 3- to 72-h-old sporelings, and in protonemata.     

Sterols and fatty acids from three species of mangrove

The hydrolysis of steryl esters on thin-layer chromatographic plates by porcine pancreatic lipase is described. The sterols and fatty acids produced were separated on the same plate, recovered, and analysed by gas-liquid chromatography for their compositions. Synthetic cholesteryl esters containing various saturated and unsaturated fatty acids and synthetic steryl oleates with various sterols were lipolysed along with steryl esters of Acanthus ilicifolius, Bruguiera gymnorhiza and Rhizophora mucronata mangrove leaves. The major sterol was sitosterol which was accompanied by cholesterol, campesterol, stigmasterol and 28-isofucosterol. In addition, stigmast-7-en-3β-ol was present in R. mucronata leaves. The component fatty acids found in all three species were 16:0, 18:0, 18:1, 18:2 and 18:3. The relative proportions of the sterols and fatty acids were significantly different from the chemotaxonomic standpoint. The results obtained by carrying out plate lipolysis for 45 min at 40° compared well with those produced by conventional chemical hydrolysis.     

Variations in sterol and triterpene contents of developing Sorghum bicolor grains

The free, esterified and glycosylated sterols and the pentacyclic triterpene esters of developing Sorghum bicolor grains were analysed by GLC and GC-MS. All the pentacyclic triterpenes were completely esterified but were not detected until 24 days after anthesis. Lupanol, multiflorenol, α-amyrin and isoarborinol were identified in the mature grains as components of the triterpene fraction but no 4,4-dimethylsterols could be found at any stage of development. A sixfold increase in total sterol per grain occurred during development. At 8 days after anthesis, 28-isofucosterol was found to be the second most abundant steryl ester. Campesterol was the major steryl glycoside and obtusifoliol was the major 4-monomethylsterol.     

Studies on the abscission of flowers and fruits of cotton (Gossypium barbadense L.)

Effects of exogenous application of auxin, GA3, abscisic acid, ethrel, methionine and α-alanine to the cut ends of the pedicels of flower buds, flowers and fruits on their abscission behaviour were studied. Fruit pedicels required more time for abscission compared with flower and flower bud pedicels. NAA inhibited abscission of all types of pedicels and the inhibition was maximum in matured fruit pedicels and minimum in flower bud pedicels. Flower pedicels were more sensitive towards the abscission promotive effects of GA3, abscisic acid and ±-alanine and the flower bud pedicels towards ethrel and methionine. The duration of Stage-I of abscission was maximum in cut pedicels of fruit and minimum in those of flower buds. Biochemical analyses revealed greater quantities of endogenous amino acids in the epicalyx of flowers with the exception of methionine and aspartic acid which were found to be present in higher quantities in the epicalyx of flower buds. Levels of IAA-like compounds were maximum in the epioalyx of flower buds and minimum in the epicalyx of flowers. Higher levels of abscisic acid were found in the epicalyx of matured fruits and the epicalyx of flower buds showed a minimum amount of abscisic acid-like compound.     

Steryl esters and their relationship to normal and diseased human central nervous system

The composition and distribution of steryl esters in human diseased or developing brain tissue has been studied. The abnormal brain conditions included sudanophilic leukodystrophy, multiple sclerosis plaque, subacute sclerosing panencephalitis, and an old cerebral infarction and two types of brain-derived tumors. In addition to the above abnormal tissue, steryl esters were also examined in developing and normal adult human brain. It was found upon subcellular fractionation that the steryl ester was localized mainly in the soluble nonparticulate material. A cholesteryl ester-rich fraction, floating on top of distilled water after centrifugation, was recovered only in the developing brain or in instances where there was myelin damage. The sterol portion of the steryl ester was largely cholesterol. The fatty acid moiety was mainly composed of C(16), C(18), and C(20) fatty acids. The dominant fatty acid was oleic acid, and the proportion of this fatty acid increased in demyelination. Although there were great differences in the quantities of steryl ester found, the fatty acid profiles of normal developing and adult brain were quite similar. As has been noted by others, the fatty acid composition of brain steryl esters most closely resembles that of brain phosphatidylcholine.     

Metabolism of monoacylglycerol and diacylglycerol by enzyme preparations from spinach leaves

Acetone powders prepared from a 20,000g participate preparation from spinach leaf catalyzed several reactions involving monoacylglycerol and diacylglycerol. When these substrates were presented as Triton X-100-mixed micelles, diacylglycerol gave rise to free fatty acids, monoacylglycerol, triacylglycerols, and steryl esters, and in the presence of ethanol, small amounts of ethyl esters of fatty acid. Monoacylglycerol gave rise to free fatty acids and diacylglycerol, and in the presence of ethanol, large amounts of ethyl esters of fatty acid. In the presence of bovine serum albumin, the conversion of monoacylglycerol to free fatty acid was retarded. In the presence of bovine serum albumin, steryl ester was an important product from diacylglycerol. The system containing Triton X-100-mixed micelles and bovine serum albumin permitted analysis of reaction products which showed diacylglycerol to be an acyl donor in steryl ester biosynthesis. All reactions observed in the mixed micelle system were transacylation reactions involving various acceptors: dipalmitoylglycerol → monopalmitoylglycerol + palmitate; monopalmitoylglycerol → glycerol + palmitate; dipalmitoylglycerol + sterol → monopalmitoylglycerol + steryl palmitate; monopalmitoylglycerol + ethanol → ethyl palmitate + glycerol; monopalmitoylglycerol → dipalmitoylglycerol (+glycerol); dipalmitoylglycerol → tripalmitoylglycerol (+monopalmitoylglycerol).     

Detailed Analyses of Individual Neutral Lipid Classes of Pneumocystis

SUMMARY Individual neutral lipid classes of Pneumocystis carinii carinii were isolated and purifed by thin-layer chromatography. The fatty acids in steryl esters, triglycerides, free fatty acids, diglycerides, and monoglycerides were quantified by gas-liquid chromatography. The fatty acid compositions of these lipids were similar to those of the neutral lipid classes in whole rat lung controls, unlike comparable studies of phospholipid classes. The free fatty alcohols of rat lung controls and P. carinii were also identified and quantified; only saturated fatty alcohols were detected.     

Lipid Composition of Cyst Stages of Globodera rostochiensis

Lipid compositional analysis was conducted on the white, yellow, and brown cyst stages of Globodera rostochiensis (golden cyst nematode). Triacylglycerols were the largest lipid fraction in all stages examined, ranging from 55-75% of total lipid. Ethanolamine phosphoglycerides and choline phosphoglycerides were present in high amounts in all cyst fractions, with a total phospholipid content of 20%, 14.7%, and 12.8% in the white, yellow, and brown cyst stages, respectively. Sterols, steryl esters, sphingomyelin, and cardiolipin were found in minor amounts in all three cyst stages and showed greater changes than other classes of lipids relative to cyst stage. The fatty acid compositions of the three cyst stages were similar. Eicosenoic acid (20:1) and arachidonic acid (20:4) were found in higher concentrations than other fatty acids in all cyst preparations; vaccenic acid (18:1) occurred at the third highest concentration. More than 78% of total fatty acids were unsaturated at all cyst stages, and more than 60% were of C20 or longer chain length. The lipid profile of all three cyst stages is consistent with invertebrate adaptation to low-temperature environments.     

Location and biosynthesis of monoterpenyl fatty acyl esters in rose petals

The upper epidermal layer of cells and the epicuticular wax surface of Lady Seton rose petals are sites of biosynthesis and accumulation, respectively, of a family of terpenyl fatty acyl esters. These esters are based mainly on the acyclic monoterpene alcohol geraniol coupled primarily to fatty acids of chain lengths 16-20 and in mass terms represent from 14% to 64% of the total monoterpenes present in the petals. The lipophilic nature of these non-volatile esters of the monoterpene alcohols contrasts with that of the lipophilic volatile parent alcohols themselves and with the hydrophilic, non-volatile, glucoside derivative of the other principal petal fragrant compounds, the phenylpropanoids, beta-phenyl ethanol and benzyl alcohol. These latter compounds are also synthesised and are resident in the petal. Biosynthetic studies confirmed that the petal upper epidermal cell layer has the capacity to incorporate mevalonic acid into the monoterpene component of the fatty acyl ester. The biosynthesis of the monoterpene component of the fatty acyl ester occurs via the mevalonic acid pathway in Lady Seton as well as in the hybrid tea rose Fragrant Cloud. In the latter flower the biosynthesis of geraniol was biosynthetically trans as was the formation of nerol and citronellol. Both geraniol and nerol were shown to be precursors of citronellol via an NADPH dependent reductase reaction. Oleic acid is assimilated into the acyl moiety of the terpenyl ester in Lady Seton isolated petal discs. It is probable that the lipophilic non-volatile terpenyl fatty acyl esters represent a stable storage form of the corresponding alcohols from their residency within the epicuticular wax layer. These acyl esters may realise, on hydrolysis, additional aroma notes from the living flower and potentially commercially significant quantities of the fragrant terpenols during oil of rose essence production.     

Chromatographic analysis of carotenol fatty acid esters in Physalis alkekengi and Hippophae rhamnoides

The carotenol fatty acid esters of two potentially valuable sources of plant carotenoids, sepals of Physalis alkekengi (Chinese lantern) and fruits of Hippophae rhamnoides (sea buckthorn), were separated by column chromatography and identified by HPLC-DAD and HPLC-MS. A chemical and an enzymatic hydrolysis were employed to identify the parent carotenoids and to remove the lipid components. Zeaxanthin and beta-cryptoxanthin esters represented the main fraction in P. alkekengi sepals and an important one in H. rhamnoides fruits. Beta-Cryptoxanthin palmitate and zeaxanthin dipalmitate were identified as major compounds in both plants. In P. alkekengi, the carotenoids were mainly (> 90%) esterified with palmitic acid, and a high proportion (> 80%) of saturated medium chain fatty acids was found (by GC-MS) in the total lipid extract. Although the total lipid extract of H. rhamnoides contained significant amounts of unsaturated fatty acids, especially oleic and palmitoleic acids, the xanthophylls were mainly esterified with saturated fatty acids. The oleoresins of both species represent potential sources of carotenoid esters and can be used as food additives, cosmetic ingredients or nutraceuticals.     

Impact of the flower stalk-boring moth Neoschoenobia testacealis (Lepidoptera: Crambidae) and water-level fluctuations on the flower and fruit production of the yellow water lily Nuphar subintegerrima (Nymphaeaceae) in irrigation ponds of western Japan

The flower and fruit production of the yellow water lily Nuphar subintegerrima and the seasonal occurrence of the flower stalk-boring moth Neoschoenobia testacealis were surveyed in two irrigation ponds in western Japan. Water-level fluctuations at each pond were measured. Flowering was observed from late May to September, and fruiting from late May to October. The yellow water lily produced cumulative numbers of 189 and 181 flowers and 121 and 129 fruits in the two ponds’ quadrats. The fruit setting rates at the two ponds were 0.64 and 0.71, and decreased in the summer. The percentage of bored flower stalks was 16 and 5%. Mature larvae bored flower stalks severely during the summer. Whenever the boring larvae attacked the flower stalks, the flower buds and flowers were aborted. There was a significant negative correlation between the fruit setting rate and the boring rate per month (number of bored flower stalks/number of all flower stalks). Whenever abruptly rising water levels (about 10 cm) submerged the flowers, the flowers were aborted too and could not set fruits. The percentages of non-setting fruit due to the rising water levels at the two ponds were 6 and 8%. Overall, our results indicated that flower stalk boring was a more important factor than water-level fluctuation in the sexual reproduction of N. subintegerrima and that N. subintegerrima was well suited to small irrigation ponds.     

Subcellular distribution of steryl ester biosynthesis in spinach leaves

Higher steryl ester biosynthetic activities were obtained with Triton X-100-phosphatidylcholine-cholesterol mixed micelles than with Tween 80-phosphatidylcholine-cholesterol mixed micelles when incubated with spinach leaf (Spinacia oleracea L.) acetone powder preparations. The best incorporation of [4-¹⁴C]cholesterol into [4-¹⁴C]cholesteryl ester was obtained with a Triton X-100-phosphatidylcholine-cholesterol (10:1:1, w/w) mixed micelle system. This mixed micelle system, however, required 1,2-dipalmitin and fatty acid-free bovine albumin for optimal activity. The reaction exhibited a diglyceride specificity since the dipalmitin requirement could be replaced with neither 1-monopalmitin nor tripalmitin. Significant amounts of steryl ester biosynthetic activity were detected in the chloroplast (1,000g pellet), mitochondrial (3,000g pellet), and microsomal (20,000g and 88,000g pellet) fractions. Little activity was detected in the water-soluble (88,000g supernatant) fraction. The highest specific activity occurred in the 88,000g pellet. The 88,000g supernatant contained a heatstable, water-soluble substance that was required for optimal steryl ester biosynthesis in all of the pellet fractions. This factor was not lost during extensive dialysis but was destroyed by ashing, indicating that it was large and organic. Silver nitrate thin layer chromatography indicated that 60% of the biosynthesized steryl esters contained saturated fatty acids in the absence of 1,2-dipalmitin and that 83% contained saturated fatty acids in the presence of 1,2-dipalmitin.     

Surface lipids of Sphaerotheca fuliginea spores

The major components (50%) of the surface lipid extract of fungal spores (5.6% of dry spore wt) of Sphaerotheca fuliginea are esters of primary alcohols and fatty acids. Esters (15%) of primary alcohols and a Δ^2t acid are present. The major acid moieties of the alkyl esters are C₂₂ and C₂₄ and of the Δ^2t alkyl ester is Δ^2t C₂₂; for both classes eicosanol is the major primary alcohol. The major ester of each class was concluded to be eicosanyl docosanoate and eicosanyl trans-2-docosenoate. Minor components are saturated and Δ^2t methyl and diol diesters and free fatty acids. The major acid moieties of the diol diesters are C₂₂ and C₂₄ and the major diol is 1,12-dodecanediol.     

苹果果实香气产生过程中氨基酸和脂肪酸含量及一些相关酶活性的变化

研究了苹果果实成熟期间香气和乙烯的产生动态,以及游离氨基酸、游离脂肪酸含量和脂氧合酶(LOX)、醇-酰基转移酶(AAT)活性的变化.结果表明,果实香气物质是随着乙烯释放的增加而产生和增加的.在此过程中,异亮氨酸大量积累.游离脂肪酸在果实香气很少时呈增加趋势;随着香气产生的增多而迅速下降;乙烯高峰过后又有增加.脂氧合酶活性随着果实成熟而提高,其活性在乙烯释放达到高峰时达到最大值,之后迅速下降.醇-酰基转移酶活性在果实开始产生香气时迅速增加,之后保持较高活性.     

Studies on furan fatty acids of salmon roe phospholipids

Mature salmon roe lipids were found to consist of triacylglycerols (63%), phospholipids (30%), sterols (4.2%), steryl esters (0.7%), and other minor components. In the steryl esters and phospholipids, furan fatty acids were detected instead of the triacylglycerols of the testes lipids in male fish. The representative 12,15-epoxy-13,14-dimethyleicosa-12,14-dienoic acid (F6) amounted to 3.8% and 0.6% of the total fatty acids in each fraction, respectively. However, the absolute amount of the acid in the phospholipid was much more than that contained in the steryl esters. The characteristic distribution of the furan acids found in the phospholipids was common to the steryl esters in the liver. Large amounts of furan acids were contained in phosphatidylcholine (PC) rather than in phosphatidylethanolamine. For positional analysis of furan fatty acids in PC, furan-containing species in the molecule were concentrated fourteenfold by using selective hydrogenation and repeated silica gel column chromatography. A series of furan fatty acids in PC was found to be exclusively linked to the sn-1 position. The amount of the acids in the roe exclusively linked to the sn-1 position. The amount of the acids in the roe phospholipids was comparable with that in the testes triacylglycerols. The physiological roles of furan fatty acids are discussed.