Basal omega-3 fatty acid status affects fatty acid and oxylipin responses to high-dose n3-HUFA in healthy volunteers

A subject's baseline FA composition may influence the ability of dietary highly unsaturated omega-3 FAs (n3-HUFA) to change circulating profiles of esterified FAs and their oxygenated metabolites. This study evaluates the influence of basal n3-HUFA and n3-oxylipin status on the magnitude of response to n3-HUFA consumption. Blood was collected from fasting subjects (n = 30) before and after treatment (4 weeks; 11 ± 2 mg/kg/day n3-HUFA ethyl esters). Esterified FAs were quantified in erythrocytes, platelets, and plasma by GC-MS. Esterified oxylipins were quantified in plasma by LC-MS/MS. Treatment with n3-HUFAs increased n3-HUFAs and decreased n6-HUFAs in all reservoirs and increased plasma n3-oxylipins without significantly changing n6-oxylipin concentrations. As subject basal n3-HUFAs increased, treatment-associated changes decreased, and this behavior was reflected in the percentage of 20:5n3 + 22:6n3 in red blood cell membrane FAs (i.e., the omega-3 index). To maintain an omega-3 index of 8% and thus reduce cardiovascular disease risk, our analyses suggest a maintenance dose of 7 mg/kg/day n3-HUFA ethyl esters for a 70-kg individual. These results suggest that the basal n3 index may have clinical utility to establish efficacious therapeutic experimental feeding regimens and to evaluate the USDA Dietary Guidelines recommendations for n3-HUFA consumption.     

脂肪酸及其氧合物对曲霉属真菌菌丝生长、产孢和黄曲霉毒素合成的影响

黄曲霉毒素是由黄曲霉菌合成的一类毒性极高、致癌性极强的次生代谢物。一般认为,高油脂含量的作物种子被曲霉属真菌感染后容易产生黄曲霉毒素,但是,脂肪酸的处理实验结果表明不同类型的脂肪酸对曲霉属真菌毒素合成的作用不同,有的促进合成,有的抑制合成。最近研究结果显示所有脂肪酸都促进黄曲霉毒素合成,但是多不饱和脂肪酸在暴露空气之后对毒素合成有抑制作用。这种抑制产毒的作用似乎是由多不饱和脂肪酸氧化所产生的脂氧合物所介导。本文结合我们的研究结果,综合评述了脂肪酸和脂氧合物调控曲霉属真菌菌丝生长、产孢和毒素合成研究的最新进展。     

细菌脂肪酸合成多样性的研究进展

与哺乳动物、真菌采用I型脂肪酸合成系统不同,细菌采用II型脂肪酸合成系统,每步反应都由独立的酶催化,因此细菌脂肪酸合成酶是研究抗菌药物的优良靶标。研究表明,在不同细菌中参与脂肪酸合成的酶都具有较高的多样性,而脂肪酸种类不同,合成方式也不尽相同,本文对此进行了总结。     

Ethanol-induced decreases in membrane long-chain unsaturated fatty acids correlate with impaired chick brain development

Exposure to ethanol at 0 days of development induced changes in total membrane fatty acid composition at 18 days of development. When exposed to ethanol concentrations ranging from 0–743.27μm/kg egg wt, decreased levels of long-chain, unsaturated membrane fatty acids and increased levels of short-chain, saturated membrane fatty acids were observed in embryonic chick brains at 18 days of development. The ratios of unsaturated membrane/saturated membrane fatty acids correlated with an ethanol-induced reduction in neuron densities within the cerebral hemispheres and three different regions of the optic lobes with correlation coefficients (r) ranging from 0.44 [F = (1, 32) 7.84; P ≤ 0.009] to 0.59 [F = (1, 32) 17.38; P ≤ 0.0002]. The ratios of long-chain/short-chain membrane fatty acids also correlated with an ethanol-induced reduction in neuron densities within the cerebral hemispheres and three different regions of the optic lobes with correlation coefficients (r) ranging from 0.51 [F = (1, 32) 11.27; P≤ 0.002] to 0.66 [F = (1, 32) 24.40; P ≤ 0.0001]. Cell fractionation studies indicated that the ethanol-induced changes in brain membrane fatty acid composition were restricted to microsomal membranes.     

Synthesis of 3-O-acyl esters of serine and threonine

The 3-O-acyl derivatives of serine and threonine have been prepared by reacting oleoyl chloride and palmitoyl chloride with N-t-butoxycarbonyl (N-T-BOC) serine and N-t-BOC threonine. The t-BOC group was removed by treatment with 4 N HCl in dioxane. The products were identified by proton magnetic resonance spectroscopy, infrared spectroscopy, elemental analysis and chromatographic properties. The O-acyl serines and O-acyl threonines were converted to their methyl esters by treatment with boron trifluoride in methanol and were converted to their dinitrophyl derivatives by treatment with dinitrofluorobenzen (DNFB). The yield of the dinitrophenyl derivatives was very high but the yield of methyl esters was low due mainly to methanolysis and loss of the fatty acyl group. The O-acyl serines and O-acyld threonines prepared will provide standards for researchers who are interested in identifying fatty acids esterified to serine and threonine hydroxyl groups in membrane proteins.     

Intramyocardial fate of 15-p-iodophenyl-β-methylpentadecanoic acid (IMPPA): Is it a good tracer of fatty acid myocardial uptake?

Summary Iodinated fatty acids (FAs) are now used in Nuclear Medicine to assess, by external detection, myocardial metabolism. Methylated FAs have been proposed as tracers of FA myocardial uptake. IMPPA is a new FA analogue in which a methyl group have been introduced in position to inhibit -oxidation and a terminal phenyl group prevents a possible omega oxidation. We have compared the intramyocardial behaviour of this FA with the 15-p-iodophenyl-pentadecanoic acid (IPPA), the straight chain analogue, and with the 15-phenyl--methylpentadecanoic acid (MPPA), the 3 of them being labelled with C14 on the carboxyl group, in isolated rat hearts perfused in a recirculating system.When IMPPA is compared to IPPA (influence of the methyl group), we observe 1 — an inhibition of -oxidation (no significant production of labelled C02 and very low radioactivity in the aqueous phase) leading to a reduced uptake, 2 — a lower radioactivity in the organic phase due to a hindrance to the esterification process both into TGs and PLs, the free FAs level being higher. When IMPPA is compared to MPPA (influence of the iodine atom), we observe 1 — the same inhibition of -oxidation, 2 — a higher myocardial radioactivity due to a much higher level of free FAs, the esterification into TGs and PLs being reduced.This study with IMPPA indicates that it is taken up by the heart and trapped there, as it is not oxydized. This long retention time, apart from giving good scintigraphic images, should make IMPPA useful to study the regional myocardial uptake of FAs.     

Fatty acid constituents of Peganum harmala plant using Gas Chromatography–Mass Spectroscopy

Fatty acid contents of the Peganum harmala plant as a result of hexane extraction were analyzed using GC–MS. The saturated fatty acid composition of the harmal plant was tetradecanoic, pentadecanoic, tridecanoic, hexadecanoic, heptadecanoic and octadecanoic acids, while the saturated fatty acid derivatives were 12-methyl tetradecanoic, 5,9,13-trimethyl tetradecanoic and 2-methyl octadecanoic acids. The most abundant fatty acid was hexadecanoic with concentration 48.13% followed by octadecanoic with concentration 13.80%. There are four unsaturated fatty acids called (E)-9-dodecenoic, (Z)-9-hexadecenoic, (Z,Z)-9,12-octadecadienoic and (Z,Z,Z)-9,12,15-octadecatrienoic. The most abundant unsaturated fatty acid was (Z,Z,Z)-9,12,15-octadecatrienoic with concentration 14.79% followed by (Z,Z)-9,12-octadecadienoic with concentration 10.61%. Also, there are eight non-fatty acid compounds 1-octadecene, 6,10,14-trimethyl-2-pentadecanone, (E)-15-heptadecenal, oxacyclohexadecan-2 one, 1,2,2,6,8-pentamethyl-7-oxabicyclo[4.3.1]dec-8-en-10-one, hexadecane-1,2-diol, n-heneicosane and eicosan-3-ol.     

Membrane fatty acid analysis of Antarctic bacteria

Abstract Randomly selected strains of a bacterial collection of marine sea-ice bacteria from Antarctica were analyzed to obtain a profile of the membrane fatty acids. Results showed that short chain saturated and unsaturated fatty acids were more common in the psychrotrophs when compared to psychrophiles. In contrast, branched-chain fatty acids were more abundant in the psychrophiles.