Fatty acid vesicles

Results obtained from recent studies on the preparation and application of fatty acid vesicles are reviewed, focusing on some of the particular properties of fatty acid vesicles in comparison with conventional phospholipid vesicles (liposomes): (i) pH dependency which allows reversible transformations from non-vesicular to vesicular aggregates, and (ii) dynamic features that place fatty acid vesicles in between conventional vesicles formed from double-chain amphiphiles and micelles formed from single-chain surfactants. There are two main research areas in which fatty acid vesicles have been studied actively during the last years: (i) basic physico-chemical properties, and (ii) applications as protocell models. Applications of fatty acid vesicles in the fields of food additives and drug delivery are largely unexplored, which is at least partially due to concerns regarding the colloidal stability of fatty acid vesicles (pH- and divalent cation-sensitivity). Recently, fatty acid vesicles were prepared from highly unsaturated fatty acids (docosahexaenoic acid) and the pH range of vesicle formation could be extended to high or low pH values by preparing mixed vesicles through addition of a second type of single-chain amphiphile that stabilizes the vesicle bilayer but itself is not a fatty acid.     

Fatty acid terminated polyanhydrides

A systematic study on the synthesis, characterization, degradation, and drug release of fatty acid terminated poly(sebacic acid) (PSA) is reported. Fatty acid terminated sebacic acid polymers were synthesized by melt condensation of acetate anhydrides of linear fatty acids (C8–C18) and sebacic anhydride oligomers to yield waxy off-white materials. Polymers with molecular weights (M_w) in the range of 9,000 and 5,000 were obtained for the 10% and 30% (weight ratio) containing fatty terminals, respectively. Up to about 30% of fatty acid terminals, the final product is mainly fatty terminated polymer with up to about 5% w/w of the symmetric fatty anhydride. Increasing amounts of fatty acid acetate anhydride in the polymerization mixture had little effect on the polymer molecular weight up to a ratio of 40 : 60 (fatty acid acetate : sebacic acid oligomer) which remains in the range of 5,000–8,000. Above this ratio the molecular weight dropped to a level of 2,000–3,000 and the percent of the symmetric anhydride increased to 10–40%. The fatty terminals had little effect on PSA melting point and crystallinity. However, the fatty terminals had a significant effect on the polymer degradation and drug release rate. PSA with 30% w/w of C14–C18 terminals degraded and released the incorporated drug for more than 4 weeks as compared with 10 days for the acetate-terminated PSA. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3337–3344, 1999     

共反应剂法合成纤维素高级脂肪酸酯

采用乙酸酐为共反应剂合成了纤维素高级脂及酸酯。运用IR,^1H NMR对合成产物的结构进行了表征。结果表明,在纤维素分子骨架上同时接技了高级脂肪酸酯基以及乙酸酯基,产物为纤维素混合酸酯。产物的酯化度值通过^1H NMR确定,可达到1.66。研究了纤维素与系列高级脂肪酸的酯化反应,结果表明,随着高级脂肪酸中碳原子数目的增加,产物的酯化度逐渐减小,而产物质量有一个先增加后减小的趋势。     

Chemistry and Biochemistry of Unsaturated Fatty Acids

Although unsaturated fatty acids have long been known to accompany saturated fatty acids in most lipids, qualitative and quantitative determination of fatty acid patterns only became possible with the advent of modern analytical methods. Present day knowledge of the chemical structure, physical properties, and metabolism of unsaturated fatty acids provides the basis for the development of new concepts of their function. Thus unsaturated fatty acids crucially determine the properties of biological membranes. Moreover, essential fatty acids are precursors of prostaglandins.     

石榴籽中脂肪酸成分分析

采用两种方法对石榴籽中的脂肪酸进行了甲酯化,所得脂肪酸甲酯经GC-MS分析.方法一共检测出14种脂肪酸,主成分为油酸、亚油酸、山嵛酸、棕榈酸、硬脂酸和二十碳烯酸;方法二共检测出24种脂肪酸,主成分为棕榈酸、硬脂酸、花生酸、山嵛酸、油酸、亚油酸、二十碳烯酸等.其中的山嵛酸等多种饱和脂肪酸均为首次从石榴籽中鉴定出.     

大鼠肝过氧化物酶体中脂肪酸的分析

 用双 (2 乙基己基 )酚酞酸酯 (DEHP)诱导大鼠肝过氧化物酶体增殖 ,再用蔗糖密度梯度离心法分离大鼠肝细胞过氧化物酶体 ,并用十七烷酸作内标 ,以毛细管气相色谱法在非极性SPB 1石英毛细管柱上对其中的 11种脂肪酸进行分离测定。正常组和诱导组的大鼠肝过氧化物酶体中的不饱和脂肪酸和长链脂肪酸所占总脂肪酸的比例及总脂肪酸的统计结果是 :诱导组的不饱和脂肪酸的含量高于正常组的 (P <0 0 5 ) ,而两个组的脂肪酸总量及长链脂肪酸的含量无明显差别。结果提示 :诱导组的大鼠肝过氧化物酶体的脂肪酸成分发生了变化 ,其膜结构与正常组的不相同。     

小鼠眼球中脂肪酸的组成分析

首次对小鼠眼球中的脂肪酸组成进行了气相色谱分析。小鼠眼球中的脂肪酸经氯仿－甲醇－盐酸混合液萃取,用甲醇－氢氧化钾法甲酯化,在２５ｍ×０．２５ｍｍＰＥＧ－２０Ｍ熔融石英毛细管柱内进行分离,眼球中１２种主要脂肪酸得到了定性和定量。测试结果提示：正常小鼠眼球中饱和脂肪酸含量较高,占全部脂肪酸含量的５２．８％;不饱和脂肪酸含量较少,但以多不饱和脂肪酸居多,占全部脂肪酸含量的１８．２％,不饱和脂肪酸与饱和脂肪酸的比值为０．６。可为有关眼疾病的治疗、预防及生化方面的深入研究提供有意义的信息。     

Correlations Between FAS Elongation Cycle Genes Expression and Fatty Acid Production for Improvement of Long-Chain Fatty Acids in Escherichia coli

Microorganisms have been used for biodiesel (fatty acid methyl ester) production due to their significant environmental and economic benefits. The aim of the present research was to develop new strains of Escherichia coli K-12 MG1655 and to increase the content of long-chain fatty acids by overexpressing essential enzymes that are involved in the fatty acid synthase elongation cycle. In addition, the relationship of β-ketoacyl-acyl carrier protein (ACP) synthase (fabH), β-ketoacyl-ACP reductase (fabG), β-hydroxyacyl-ACP dehydrase (fabZ), and β-enoyl-ACP reductase (fabI) with respect to fatty acid production was investigated. The four enzymes play a unique role in fatty acid biosynthesis and elongation processes. We report the generation of recombinant E. coli strains that produced long-chain fatty acids to amounts twofold over wild type. To verify the results, NAD⁺/NADH ratios and glucose analyses were performed. We also confirmed that FabZ plays an important role in producing unsaturated fatty acids (UFAs) as E. coli SGJS25 (overexpressing the fabZ gene) produced the highest percentage of UFAs (35 % of total long-chain fatty acids), over wild type and other recombinants. Indeed, cis-9-hexadecenoic acid, a major UFA in E. coli SGJS25, was produced at levels 20-fold higher than in wild type after 20 h in culture. The biochemically engineered E. coli presented in this study is expected to be more economical for producing long-chain fatty acids in quality biodiesel production processes.     

气相色谱法测定线虫中的脂肪酸含量

ematode is a small organism and the traditional purification method needs a lot of nematodes , but it is difficult for us to foster many nematodes.The fatty acids in nematode were esterified directly in our analytical method,so that,the error is reduced the and sensitivity is improved. The results showed that thisimproved analysis method could be used for rapid and satisfactory determination of the fatty acid change during storagr of this group of nematodes.     

榴莲中脂肪酸成分的色谱-质谱分析

报道了用色谱－质谱分析榴莲中的脂肪酸及其含量。结果表明榴莲含有丰富的对人体有益的脂肪酸,是一种具有较高食用价值和药用价值的水果。     

Surface Activity of Fatty Acid Salts in Aqueous Solutions

The surface activity of sodium, potassium and, ammonium salts of fatty acids [stearic, oleic, synthetic fatty acids (C_{1 3}-C_{1 5} fractions), higher fatty acids contained in bottoms after separation of volatile fatty acids from cotton oil] in aqueous solutions was studied and analyzed.     

GC Analysis of the Fatty Acid Composition of Yak Kidney

To obtain valuable information for development of potential commercial products from yak kidney, which is usually treated as waste, the fatty acid composition of kidneys from yak reared in Gansu province, China, was investigated by gas chromatography. Fifteen different fatty acids were identified. The major fatty acids are oleic acid (33.3%), stearic acid (20.2%), and palmitic acid (18.4%). More interestingly, several important and essential fatty acids were also identified, including conjugated linoleic acid (2.94%), omega-3 fatty acids, for example docosahexaenoic acid (1.47%), eicosapentaenoic acid (1.11%) and alpha linolenic acid (0.37%), and omega-6 fatty acids, for example arachidonic acid (2.86%) and linoleic acid (1.98%). The results show that the fatty acid composition of yak kidney is of reasonable value and is suitable for further development of possible commercial products. This is the first report of the fatty acid profile of yak kidney.

     

Light‐Driven Enzymatic Decarboxylation of Fatty Acids

The photoenzymatic decarboxylation of fatty acids to alkanes is proposed as an alternative approach for the synthesis of biodiesel. By using a recently discovered photodecarboxylase from Chlorella variabilis NC64A (CvFAP) we demonstrate the irreversible preparation of alkanes from fatty acids and triglycerides. Several fatty acids and their triglycerides are converted by CvFAP in near‐quantitative yield and exclusive selectivity upon illumination with blue light. Very promising turnover numbers of up to 8000 were achieved in this proof‐of‐concept study.     

Use of RP-TLC to Investigate the Solubility in Water of Fatty Acids,Hydroxy Fatty Acids and their Esters

JPC – Journal of Planar Chromatography – Modern TLC - Long-chain fatty acids and hydroxy fatty acids and their esters have been separated by reversed-phase thin-layer chromatography...     

气相色谱法用于分枝杆菌脂肪酸组成与菌种鉴定的研究

采用非极性毛细管柱气相色谱法对３株分枝杆菌细胞脂肪酸化学组成进行了研究,得到特异性指纹识别图,并对７例临床分离的分枝杆菌进行了鉴别。结果表明,结核菌硬脂酸（ＴＳＡ）为分枝杆菌属的特征组分,其含量与其他中长链脂肪酸的百分组成随菌种不同而异。     

Carnitine and Fatty Acid Oxidation in Sepsis

Fatty acid oxidation is usually thought of as being a preferred ATP source during sepsis, as shown by the decrease in respiratory quotient in septic patients and animals. However, fatty acid oxidation may be impaired relative to circulating triglyceride levels, resulting in increased cycling between triglycerides and non-esterified fatty acids. The rate of fatty acid oxidation is critically dependent on the stage of sepsis. Carnitine may be depleted during sepsis by a combination of muscle wasting, erythrocyte haemolysis, decreased tissue uptake, reduced kidney reabsorption of free carnitine, and increased excretion of acyl-carnitines. Whether there may be any beneficial effects of carnitine supplementation during sepsis, is, as yet, uncertain.     

Carnitine and Fatty Acid Oxidation in Sepsis

Summary. Fatty acid oxidation is usually thought of as being a preferred ATP source during sepsis, as shown by the decrease in respiratory quotient in septic patients and animals. However, fatty acid oxidation may be impaired relative to circulating triglyceride levels, resulting in increased cycling between triglycerides and non-esterified fatty acids. The rate of fatty acid oxidation is critically dependent on the stage of sepsis. Carnitine may be depleted during sepsis by a combination of muscle wasting, erythrocyte haemolysis, decreased tissue uptake, reduced kidney reabsorption of free carnitine, and increased excretion of acyl-carnitines. Whether there may be any beneficial effects of carnitine supplementation during sepsis, is, as yet, uncertain.     

Fatty acids of Rhodobryum ontariense (Bryaceae)

The chemical composition of Rhodobryum ontariense (Kindb.) Kindb. has not been previously investigated. Fatty acids of this moss were analysed qualitatively and quantitatively with an aim to identify its corresponding pattern. A total of eight fatty acids were identified including two acetylenic ones: 9,12,15-octadecatrien-6-ynoic acid (42.26%), α-linolenic acid (20.32%), palmitic acid (14.31%), 9,12-octadecadienoic-6-ynoic acid (13.31%), linoleic acid (5.25%), oleic acid (2.47%), stearic acid (1.14%) and γ-linolenic acid (0.92%). To our knowledge, this is the first record of acetylenic fatty acids in the genus Rhodobryum. In general, acetylenic fatty acids vary considerably among different moss groups and have been used as a chemotaxonomic character in bryophyte classifications. Other species of Rhodobryum from Asia have been traditionally used in ethno medicine by indigenous cultures. Two fatty acids of those reported here, 9,12,15-octadecatrien-6-ynoic and α-linolenic acid, have known cardio protective activity, which supports respective claims of traditional herbal use of these mosses.     

Fatty Acid Composition of Pistachio Nuts in Turkey

In this study oil yields and fatty acid compositions in the kernels of two varieties (Uzun and Siirt) of pistachio grown in different region of Turkey were investigated. Kernel oils were obtained by Soxhlet extraction using petroleum ether. The yields were found to be 57.1-58.9% and 56.1-62.6 respectively for the Uzun and Siirt varieties, on a moisture-free basis. Fatty acid composition of oils were analysed by GC/MS in the methyl ester form. Fourteen fatty acid components representing about 99% of the total oils were characterised. Oleic acid (55.4-62.6% and 60.7-65.5%, respectively) was the main fatty acid component in both varieties. Pentadecanoic acid, (Z)-7-hexadecenoic acid, margaric acid, Z-7-octadecenoic acid, arachidic acid, 11-eicosenoic acid, and behenic acid were detected in both varieties for the first time.     

脂肪酸糖酯类表面活性剂的合成及应用

脂肪酸糖酯是一类绿色、安全、可生物降解的非离子型表面活性剂,因其具有良好的乳化能力和杀菌性能以及对皮肤刺激性低等诸多优点而被广泛应用于食品、医药、化妆品和农业领域。本文对脂肪酸糖酯的合成及应用进行了综述,从而为深入研究并开发脂肪酸糖酯类表面活性剂提供参考。