Lipid composition ofHerrania andTheobroma seeds

The seeds of nineHerrania and nineTheobroma species were surveyed for fatty acid, sterol, tocopherol and tocotrienol compositions. Principal component and cluster analyses suggested that these analytes could be used collectively as chemotaxonomic criteria to differentiate theHerrania species from theTheobroma species, as well as to provide subgroup distinctions within each genus for comparison to the existing classification schemes.     

Lipid of sunflower seeds produced in japan

The fatty acid composition and tocopherol content of sunflower seeds from experimental plantings in Japan were determined. Lipid content of sunflower seed was almost the same irrespective of the variety and the average lipid content was 38.8%. The saturated fatty acids were low and the combined percentage of linoleic acid and oleic acid was ca. 90%. The ratio of oleic acid to linoleic acid largely varied with the planting location and date. There was a strong correlation between the percentage of linoleic acid or oleic acid and the temperature during maturation of seed. The sunflower seed contained predominantly α-tocopherol and small amounts ofβ-,γ- and δ-tocopherol. There was no correlation between a-tocopherol content and the percentage of linoleic acid.     

Effects of streptozotocin-induced diabetes on microsomal long-chain fatty acyl-CoA synthetase and hydrolase

Streptozotocin-induced diabetes significantly decreased rat liver microsomal long-chain fatty acyl-CoA (LCA-CoA) hydrolase. The decrease was observed using either palmitoyl-CoA (35 per cent, p<0.01) or oleoyl-CoA (23 per cent, p<0.01) as the substrate for the enzyme. Under the same conditions, diabetes did not significantly alter activity of LCA-CoA synthetase. Daily subcutaneous injections of protamine zinc insulin (10–12 units/day) into the diabetic rats returned their blood glucose to normal but only partially corrected the LCA-CoA hydrolase activity and did not effect LCA-CoA synthetase activity. The decreased LCA-CoA hydrolase and the unchanged LCA-CoA synthetase activities in the diabetic rat liver were interpreted as factors that may contribute to elevation of fatty acyl-CoA levels in the diabetic liver.     

Lipid changes during pre-germination and germination ofstriga asiatica seeds

Witchweed (Striga asiatica L. Kuntze) seeds were incubated at 28 C in a moist environment for a 14-day period, after which seeds germinated only when exposed to specific natural or synthetic germination stimulants. Changes in lipid composition were determined during germination of witchweed seeds and during early seedling growth. Witchweed seeds contained 37.5% (w/w) oil. Increased levels of monogalactosyl-diacylglycerol and phosphatidylglycerol suggested the enlargement or multiplication of plastids after witchweed seeds had germinated. In contrast to the usual course of events in seeds with high oil reserves, witchweed seeds did not hydrolyze triacylglycerol rapidly during or after germination. These findings indicated that triacylglycerol in germinating witchweed seeds was conserved for subsequent use during haustorial formation and host invasion.     

Lipid composition of millet (Pennisetum americanum) seeds

The composition of lipids extracted from a sample of millet seeds by each of 8 solvent systems is reported. Lipid components were separated by silicic acid column and thin layer chromatography (TLC) and quantitated by analysis of fatty acid methyl esters by gas liquid chromatography (GLC), with heptadecanoic acid as internal standard. Best results were obtained by extraction with hot water-saturated butanol. Lipids extracted amounted to 7.2% of the seed dry weight and consisted of 85% neutral lipids, 12% phospholipids and 3% glycolipids. Neutral lipids contained mostly (85%) triacylglycerols and small amounts of mono- and diacylglycerols, sterols and free fatty acids. Sterols consisted of campesterol, stigmasterol and 2 unidentified sterols, occurring in the same proportions in free and esterified forms. Ten glycolipid and 10 phospholipid components were separated and characterized. Contrary to previously published observations, lysophosphatidylcholine was the major phospholipid (42%) in millet seeds; smaller amounts of phosphatidylcholine (24%), lysophosphatidylethanolamine (21%) and trace amounts of phosphatidylglycerol, phosphatidic acid, phosphatidylserine and phosphatidylinositol also were present. The major glycolipids were esterified sterol glycoside, sterol glycoside, monogalactosyldiacylglycerol, digalactosyldiacylglycerol and cerebrosides (ceramide monohexosides).     

Lipid synthesis by perfused lung

An isolated lung ventilated with pulses of negative pressure and perfused through the pulmonary vasculature was utilized for the study of 3-sn-phosphatidylcholine synthesis. The perfusion fluid consisted of a Krebs-Ringer phosphate buffer with 6% bovine serum albumin, pH 7.4, and the appropriate substrate. The simultaneous incorporation of (1-¹⁴C) palmitate and (2-³H) glycerol and the simultaneous incorporation of (CH₃-¹⁴C) choline and (CH₃-³H) methionine were examined. From these experiments it is concluded: 1) lung tissue incorporates (2-³H) glycerol into 3-sn-phosphatidylcholine to a greater extent than any other lipid examined; 2) both choline and methionine contribute to the synthesis of 3-sn-phosphatidylcholine, and 50–70% of the label in its nitrogen base is derived from choline and 30–50% from methionine; and 3) a high PO₂ appears to reduce the synthesis of 3-sn-phosphatidylcholine.     

Lipid synthesis by rat lung in vitro

Oxidation and lipogenesis in isolated rat lung tissue were studied in vitro. The minced tissue was incubated in a Krebs-Ringer bicarbonate buffer (pH 7.4) with 1-¹⁴C-acetate, 2-¹⁴C-pyruvate, U-¹⁴C-D-glucose, 1,5-¹⁴C-citrate, 1-¹⁴C-laurate, 1-¹⁴C-palmitate, 1-¹⁴C-stearate, 1-¹⁴C-oleate, 1-¹⁴C-linoleate. The lung tissue readily oxidized all of these substrates to¹⁴CO₂ and incorporated them into¹⁴C-lipids with the exception of 1,5-¹⁴C-citrate, for which there was no significant incorporation into¹⁴C-lipids. Most of the lipid¹⁴C was recovered in phospholipids, more specifically phosphatidyl choline. Twenty-eight per cent of glucose carbons was incorporated into the fatty acid moiety of phospholipids, while more than 90% of the carbons of other substrates was found in phospholipid fatty acids. The main fatty acid of the phospholipid fraction synthesized from acetate, pyruvate or glucose was palmitic acid. The oxidation of fatty acids was apparently influenced both by the carbon chain length and number of double bonds. Accumulation of¹⁴C-fatty acids in the tissue was observed when fatty acids were used as substrates; this finding suggests that the rate limiting step was not in the uptake of fatty acids. Chemical degradation of¹⁴C-myristic and palmitic acids obtained by hydrolysis of phospholipids biosynthesized from 1-¹⁴C-laurate indicated that the phospholipid fatty acids were synthesized via the de novo synthesis pathway. Presented at the AOCS-ISF World Congress, Chicago, September 1970.     

Lipid synthesis in cultured human embryonic fibroblasts

We describe here the pathways by which human embryonic fibroblasts synthesize lipids. In these studies, we quantitated the phospholipids by their phosphorus content and by their acyl components. These determinations defined both the chemical composition of the cellular membranes as well as their metabolic turnover. Using radiolabeled precursors, we have shown (a) synthesis of the glycerol moiety via glycolysis and the action of glycerokinase, (b) utilization of both exogenously added and endogenously synthesized fatty acids, (c) synthesis de novo of phosphatidyl choline and phosphatidyl ethanolamine from their base precursors, and (d) the methylation of phosphatidyl ethanolamine yielding phosphatidyl choline. Dividing cells synthesized phosphoglyceride more rapidly than cells in the stationary phase. However, considerable turnover of cellular lipid did occur in the stationary phase.     

Lipid hydrolysis and oxidation on the surface of milled rice

The changes in milled rice FFA content and composition and in conjugated diene (CD) content and bacterial, yeast, and mold counts were determined at 24, 37, and 50°C and 70% RH over 50 d. There was a rapid rate of FFA formation during the first few days of storage, which was optimal at 37°C, but that slowed after 2, 4, and 5 d at 37, 24, and 50°C, respectively. There was a second increase in FFA after about day 12 that increased with increasing temperature, indicating nonlipase hydrolysis. Linoleic and oleic acids were the main components of the total FFA produced on the surface of milled rice. The pattern of CD development followed that of FFA increase. Bacterial growth correlated with increased FFA levels after 12 d of storage, suggesting that bacterial lipase rather than bran lipase may be responsible for rice lipid hydrolysis     

The sequence of formation of fatty acids in developing soybean seeds

Summary Excised Lincoln soybean stems bearing pods and leaves were supplied with C¹⁴ labeled-sucrose for brief periods, and the subsequent appearance of radio-activity in the different fatty acids was observed up to 18 days. The individual fatty acids were separated as their 2,4-dinitrobenzenesulfenyl chloride derivatives and the specific activity of the different fractions were determined. Radioactivity appeared in the fatty acids in the following order: oleic, saturated, linoleic, linolenic. Consistent presence of highest specific activity in the oleic acid fraction indicated that oleic may be converted to the other acids, at least to some extent. Journal Paper No. 719 of the Purdue Agricultural Experiment Station, Layfayette, Ind.     

Change of substrate specificity of rat liver microsomal fatty acyl-CoA synthetase activity by triton X-100

The effect of Triton X-100 on the activities and apparent molecular size of fatty acyl-CoA synthetase, solubilized and partially purified from rat liver microsomes, was studied. In the presence of Triton X-100, the activity for lignoceroyl-CoA synthesis was decreased, but activity was restored when the detergent was removed. The appearance and disappearance of lignoceroyl-CoA synthesis appeared related to the size, of the aggregated from of the enzyme. On the other hand, activity for palmitoyl-CoA synthesis was not significantly affected by the detergent. Because available evidence suggests that both fatty acids are converted to CoA esters by the same enzyme, it seems likely that the substrate specificity of the enzyme is influenced by changes in the aggregation state branes may determine the substrate specificity of acyl-CoA synthetase.     

Tocopherols accumulation in developing seeds and pods of rapeseed (Brassica napus L.)

The accumulation of dry matter, chlorophyll, and tocopherols was monitored in developing seeds and pods of three rapeseed genotypes with contrasting tocopherol profiles from shortly after anthesis to maturity. Three phases of tocopherols accumulation were observed. Phase I, from 12 to 41 days after flowering (DAF), was characterized by a slow accumulation of both α- and γ-tocopherol. Phase II, from 41 to 53 DAF, showed the highest tocopherols accumulation rates, with more active accumulation of γ- than α-tocopherol in the lines characterized by an α- to γ-tocopherol ratio below the unity. Final differences in the α- to γ-tocopherol ratios among genotypes were caused by different accumulation rates between both tocopherol derivatives in Phase II. Both total tocopherols content and the α- to γ-tocopherol ratio remained constant in Phase III, from 53 DAF to maturity. Changes on chlorophyll and tocopherols contents in pods during development were similar to those previously reported in senescing leaves. No export of tocopherols from pods to seeds throughout seed development was detected.     

Lipid synthesis in peripheral nerve from alloxan diabetic rats

Decreased conduction velocity in the peripheral nerves of rats is noted after induction of diabetes. The slowing of nerve conduction is accompanied by a decrease in the in vitro incorporation of radioactive precursors into some of the myelin lipids isolated from nerve segments. Cerebroside synthesis is more depressed than that of any other fraction. A change in the type of cerebrosides synthesized is seen with a pronounced decrease in the rate of incorporation of saturated fatty acids. Winner, AOCS Bond Award. Presented at the AOCS Meeting, Cincinnati, October 1965.     

Interrelationship between the dietary regulation of fatty acid synthesis and the fatty acyl-CoA desaturases

In this paper we present further evidence for the close control of fatty acid synthetase and stearoyl-CoA desaturase. Furthermore, we have established that whereas dietary palmitic acid may influence the activity of this desaturase but not of fatty acid synthetase, dietary linoleic acid appears to control both these enzymes. Finally, we have studied the influence of dietary fat and carbohydrate on the activities of the delta6 and delta5 desaturases. The former is only slightly affected by these dietary components. The delta5 desaturase activity is stimulated as the dietary fat content rises but is unaffected by dietary carbohydrate. The control of these enzymes is therefore independent of the control of fatty acid synthetase and stearoyl-CoA desaturase. From the data presented, the magnitude of the controlling effect of polyunsaturated fatty acids on fatty acid synthetase and stearoyl-CoA desaturase activity is determined and its relevance to lipogenesis in man based on daily intake of carbohydrate and linoleic acid is discussed.     

Lipid composition of rice (Oryza sativa L.) bran

The composition of lipids of bran from three varieties of rice is reported. Lipids extracted amounted to 21.9–23.0% of the bran dry weight and consisted of 88.1–89.2% neutral lipids, 6.3–7.0% glycolipids and 4.5–4.9% phospholipids. Neutral lipids consisted mostly of triacylglycerols (83.0–85.5%), monoacylglycerols (5.9–6.8%) and small amounts of diacylglycerols, sterols and free fatty acids. Three glycolipids and eight phospholipids were separated and characterized. Acylated steryl glucoside and digalactosyldiacylglycerol were the main glycolipids, while monogalactosylmonoacylglycerol was present in small amounts. The major phospholipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidic acid. Phosphatidylglycerol, lysophosphatidylcholine, lysophosphatidylethanolamine and acyl-phosphatidylethanolamine were present in small quantities.     

Studies on the changes in fatty acid composition in developing seeds. I.

Oils from castor seeds at different stages of ripening have been studied. The fatty acid composition has been determined by paper chromatography. The ratio of the weight of the kernel to the weight of the seed coat changes from 1.0: 1.24 (14 days) to 1.0:0.48 (45 days) and the oil content of the seed coat is negligible. Amounts of the individual fatty acids in 1 g of kernel as well as in a single seed have been shown. The amounts of ricinoleic, linoleic and stearic acids gradually increase with the ripening of the seeds whereas the amounts of oleic and palmitic acid after an initial increase upto 28 days gradually decrease towards the later stages of growth when the amounts are calculated on the basis of a single seed.     

KMnO_4改性稻壳、稻杆水热炭吸附染料的研究

以稻壳、稻杆为原料,不同浓度KMnO4为水热溶剂,一步完成炭化与改性,并对其进行等电点测定,SEM、FTIR表征。通过静态吸附实验,探究KMnO4改性水热炭对阴、阳离子染料的吸附效果,以及初始染料浓度、样品投加量等的影响。通过吸附等温模型(Langmuir-Freundlich、Langmuir、Freundlich和Temkin)、动力学模型(准一级、准二级和Elovich动力学模型)、吸附机理(颗粒内扩散、Boyd外扩散模型)探究表明,Langmuir-Freundlich、准二级动力学和Elovich模型适合描述吸附过程,膜扩散速率和颗粒内扩散速率共同影响着吸附反应速率。     

Lipid components of borage (Borago officinalis L.) seeds and their changes during germination

The changes in composition of total and neutral lipids (NL) as well as glycolipids (GL) and phospholipids (PL) of borage (Borago officinalis L.) seeds, germinated in the dark at 25^°C for 10 d, were studied. Total lipids constituted 34.0% of the dry matter of borage seeds. During germination, the content of total lipids was decreased by 95%. NL accounted for 95.7% of total lipids prior to germination and were composed of triacylglycerols (TAG; 99.1%), diacylglycerols (DAG; 0.06%), monoacylglycerols (MAG;0.02%), free fatty acids (FFA;0.91%), and sterols (0.02%). The content of TAG was significantly (P≤0.05) decreased, while that of other components, such as MAG and FFA, significantly (P≤0.05) increased during germination. However, the content of DAG did not change. GL and PL accounted for 2.0 and 2.3% of total lipids, respectively, and their contents significantly (P≤0.05) increased as germination proceeded. The thin layer chromatography-flame-ionization detection studies showed that phosphatidylcholine (PC; 69.7%) was the major PL present. The total content of phosphatidylserine (PS) and phosphatidylethanolamine (PE), which were coeluted, was 18.2%; phosphatidic acid (PA) was present at 11.2% of the total PL fraction. Lysophosphatidylcholine was detected at 0.9%. The proportion of PC, PS, and PE significantly (P≤0.05) decreased during germination, but that of PA increased (P≤0.05) markedly. The fatty acid composition of lipid fractions changed as germination proceeded. The predominant fatty acids of total lipids, NL, and GL were linoleic and linolenic acids, while those of PL were linoleic and palmitic acids. The present study demonstrated that the overall changes of lipids seen in borage seeds during germination agree well with results for other oilseeds. Changes in lipid compositions during germination result from the formation of tissues and metabolic interconversion of lipid classes. Rapid changes in lipid composition during seed germination may enhance the nutritional value of the sprouts.