Type 2 Diabetes Associated Changes in the Plasma Non-Esterified Fatty Acids,Oxylipins and Endocannabinoids

Type 2 diabetes has profound effects on metabolism that can be detected in plasma. While increases in circulating non-esterified fatty acids (NEFA) are well-described in diabetes, effects on signaling lipids have received little attention. Oxylipins and endocannabinoids are classes of bioactive fatty acid metabolites with many structural members that influence insulin signaling, adipose function and inflammation through autocrine, paracrine and endocrine mechanisms. To link diabetes-associated changes in plasma NEFA and signaling lipids, we quantitatively targeted >150 plasma lipidome components in age- and body mass index-matched, overweight to obese, non-diabetic (n = 12) and type 2 diabetic (n = 43) African-American women. Diabetes related NEFA patterns indicated ∼60% increase in steroyl-CoA desaturase activity and ∼40% decrease in very long chain polyunsaturated fatty acid chain shortening, patterns previously associated with the development of nonalcoholic fatty liver disease. Further, epoxides and ketones of eighteen carbon polyunsaturated fatty acids were elevated >80% in diabetes and strongly correlated with changes in NEFA, consistent with their liberation during adipose lipolysis. Endocannabinoid behavior differed by class with diabetes increasing an array of N-acylethanolamides which were positively correlated with pro-inflammatory 5-lipooxygenase-derived metabolites, while monoacylglycerols were negatively correlated with body mass. These results clearly show that diabetes not only results in an increase in plasma NEFA, but shifts the plasma lipidomic profiles in ways that reflect the biochemical and physiological changes of this pathological state which are independent of obesity associated changes.     

Temperature-induced Changes in the Synthesis of Unsaturated Fatty Acids by Acanthamoeba castellanii

ABSTRACT. Major fatty acid components of Acanthamoeba castellanii lipids extracted after growth at 30°C include myristate, palmitate, stearate and the polyunsaturates linoleate, eicosadienoate, eicosatrienoate and arachidonate, with oleate as the sole major monounsaturated fatty acid. By comparison, growth at 15°C gave increased linoleate, eicosatrienoate and arachidonate, but decreased oleate and palmitate. When the growth temperature was shifted downwards from 30°C to 15°C, increased lipid unsaturation occurred over a period of 24 h; thus decreases of oleate and eicosadienoate were accompanied by increases in linoleate, eicosatrienoate, arachidonate and eicosapentaenoate. An upwards shift from 15°C to 30°C gave negligible alterations in fatty acid composition over a similar period. At 15°C organisms rapidly use [1-¹⁴C] acetate for de novo fatty acid synthesis; stearate is converted via oleate to further desaturation and chain elongation products. Similar short term experiments at 30°C indicate only de novo synthesis and Δ9-desaturation; synthesis of polyunsaturates was a much slower process. Rapid incorporation of [1-¹⁴C] oleate at 30°C was not accompanied by metabolic conversion over two hours, whereas at 15°C n-6 desaturation to linoleate was observed. Temperature shift of organisms from 15°C to 30°C in the presence of [1-¹⁴C] acetate revealed that over half of the fatty acids in newly-synthesised lipids were saturated, but the proportions of unsaturated fatty acids increased with time until the total polyenoate components reached 17% after 22 h. A shift of temperature in the reverse direction gave a corresponding figure of 60% for polyunsaturated fatty acids. These results emphasize the importance of n-6 desaturation in the low temperature adaptation of Acanthamoeba castellanii .     

Changes in Volatile Fatty Acids and Free Amino Acids during Air-Tobacco Stalks

In our searching program for novel sorbicillin related compounds, three novel compounds, spirosorbicillinols A (1), B (2), and C (3), were isolated from the fermentation broth of the USF-4860 strain isolated from a soil sample. The planar structures of compounds 1–3 were determined from spectroscopic evidence and degradation reaction, and that of 1 was the same as that of 2. The relative stereochemistries of compounds 1–3 were determined by ¹H-¹H coupling constants, the elucidation of HMBC and NOESY spectra in detail. 1 and 2 were stereoisomers at C8 position, each other. We propose that compounds 1 and 2 were formed by exo and endo intermolecular Diels-Alder reaction between sorbicillinol as a diene and scytolide (proposed precursor-1) as a dienophile, respectively. Similarly, we propose that compound 3 was formed by an endo intermolecular Diels-Alder reaction between sorbicillinol and proposed precursor-2.     

Fatty Acids Associated with the Cell Wall in Film Strains of Saccharomyces

Fatty acid contents were estimated in the cell wall of Saccharomyces. The fatty acids responsible for cell wall hydrophobicity were classified by ease of extraction to ‘readily extractable’ and ‘bound’ acids. The readily extractable fatty acids were easily extracted with pentane and chloroform-methanol. The fatty acids extracted with chloroform-methanol were quite effective for cell wall hydrophobicity, but the fatty acids extracted with pentane were not. The bound fatty acids comprised in the phospholipids phosphatidylethanolamine and phosphatidylserine, which were rigidly associated with the cell wall. These phospholipids were not extractable until they were released from the cell wall by pronase. Chloroform-methanol extraction caused a reduction in cell wall phospholipid content, particularly after treatment with pronase. The fatty acid content of the resultant cell wall was lowered to below 7% of initial content. Phospholipids contained more saturated fatty acid than readily extractable lipids. Phospholipids greatly contributed to cell wall hydrophobicity of various film strains of Saccharomyces.     

多不饱和脂肪酸合成途径研究进展

多不饱和脂肪酸在大多数生物体膜生物学和信号传递过程中起着至关重要的作用。最近研究发现,一些深海生物合成多不饱和脂肪酸并非由饱和脂肪酸的延长及脱饱和反应,而是由聚酮合酶途径(polyketide synthase,PKS)直接合成。介绍多不饱和脂肪酸的生物合成并总结近年来聚酮合酶这一新途径及其分子机制的研究进展。     

ADIPOSE TISSUE : Morphological Changes Associated with Lipid Mobilization

Morphological changes associated with mobilization of lipid were studied in epididymal adipose tissue from fasted and from alloxan diabetic rats. In both groups of animals a decrease in lipid content was accompanied by the formation of complex frond-like cytoplasmic processes and of loops and folds of basement membrane which extended from cell surfaces. These changes, evident after 1 day of fasting, increased in magnitude with increasing weight loss. As the lipid content of the cell decreased further, lipid-cytoplasmic interfaces became irregular and convoluted. Cytoplasmic microvesicles were prominent and appeared to be greatly increased in number. Rosette-like structures composed of microvesicles were observed in both lipid-depleted fat cells and endothelium. The interpretation of these changes and their physiological significance are discussed in terms of the physical and chemical properties of lipids and lipid metabolism. It is postulated that microvesicles may represent the mechanism of transport of free fatty acids in fat cells and in endothelium. Hypotheses are proposed and illustrated schematically for the mode of formation of microvesicular rosettes, for the mobilization and uptake of lipids by fat cells, and for the transport of lipids through endothelium.     

Changes in Nucleic Acids Associated with Maturation and Senescence in Hedera helix

Significant changes in nucleic acids are associated with both maturation and senescence of Hedera helix leaf tissues. DNA content was unaffected by senescence, and there were no quantitative differences between juvenile and transitional forms. The adult tissue, however, contained less DNA than the other forms. The total RNA content was reduced by senescence in juvenile and transitional tissue but not in adult. Maturation, on the other hand, progressively decreased the total RNA content. Similar changes in sRNA and rRNA indicate that maturation involves quantitative changes in these fractions. Quantitative differences in the nucleotide analyses suggest that different sRNA and rRNA species are responsible for the biological processes associated with maturation.     

Effect of Short-Chain Fatty Acids and Soil Atmosphere on Tylenchorhynchus spp.

Short-chain fatty acids can be produced under anaerobic conditions by fermentative soil microbes and have nematicidal properties. We evaluated the effects of butyric and propionic acids on death and recovery of stunt nematodes (Tylenchorhynchus spp.), a common parasite of turfgrass. Nematodes in a sand-soil mix (80:20) were treated with butyric or propionic acid and incubated under air or N₂ for 7 days at 25 °C. Amendment of soil with 0.1 and 1.0 µmol (8.8 and 88 µg) butyric acid/g soil or 1.0 µmol (74 µg) propionic acid/g soil resulted in the death of all nematodes. The composition of the soil atmosphere had no effect on the nematicidal activity of the acids. Addition of hydrochloric acid to adjust soil pH to 4.4 and 3.5 resulted in nematode mortality relative to controls (41% to 86%) but to a lesser degree than short-chain fatty acids at the same pH. Nematodes did not recover after a 28-day period following addition of 10 µmol butyric acid/g soil under air or N₂. Carbon mineralization decreased during this period, whereas levels of inorganic N and microbial biomass-N remained constant. Short-chain fatty acids appear to be effective in killing Tylenchorhynchus spp. independent of atmospheric composition. Nematode mortality appears to be a function of the type and concentration of fatty acid and soil pH.     

Lipolytic Activity and the Utilization of Fatty Acids Associated with Bat Sebum by Pseudogymnoascus destructans

Mycopathologia - Pseudogymnoascus destructans is the causative agent of a fungal infection of bats known as white-nose syndrome (WNS). Since its discovery in 2006, it has been responsible for...     

High-cholesterol Diets Induce Changes in Lipid Composition of Rat Erythrocyte Membrane Including Decrease in Cholesterol,Increase in α-Tocopherol and Changes in Fatty Acids of Phospholipids

Effects of high dietary cholesterol on erythrocyte membrane lipids were studied. Feeding rats with a diet containing 0.5% cholesterol and 0.15% sodium cholate for two weeks induced changes in erythrocyte membrane lipids including a decrease in cholesterol, an increase in α-tocopherol (α-Toc) and changes in the fatty acid composition of phospholipids. Oleic acid and linoleic acid increased, while arachidonic acid decreased in phosphatidylcholine. Saturated fatty acids decreased and unsaturated fatty acids increased in phosphatidylethanolamine. Almost the same changes in membrane lipids were also noted after six weeks of feeding rats with the diet. A diet containing 0.5% cholesterol but without sodium cholate caused a decrease in erythrocyte cholesterol and an increase in erythrocyte α-Toc after two weeks of feeding, as compared to the basal diet, indicating that high dietary cholesterol, but not sodium cholate, was responsible for these changes in the erythrocyte membrane.     

植物不饱和脂肪酸的生物合成及调控

不饱和脂肪酸是植物细胞中的一类重要代谢物质,是组成细胞膜的主要成分,对调节细胞的生理功能起着重要作用。不饱和脂肪酸也是人类必须的一类营养物质,对健康发挥着重要作用。因此,研究植物不饱和脂肪酸的合成和调控机制具有着重要的理论和现实意义。不饱和脂肪酸的合成主要发生在质体和内质网,由一系列编码基因控制,并受到外在环境胁迫及发育的调控。本研究综述了近年来不饱和脂肪酸合成和调控机制相关的一些研究进展,解析了不饱和脂肪酸合成的一些关键基因,以期为将来利用相关基因进行种质创新,从而实现改良食用油品质或提升植物的抗性育种提供思路和实践。     

Changes in Lipid and Fatty Acid Metabolism of Vicia faba Mesophyll Protoplasts

The metabolism of the major polar and neutral lipids of Viciafaba protoplasts isolated from ¹⁴CO₂-fed leaves has been examined.The results show large losses in the radioactivity found inphosphatidylcholine and monogalactosyldiacylglycerol while thatof phosphatidylglycerol was stable. This loss was accountedfor by a rapid increase in the ¹⁴C content of the neutral lipids,particularly the triacylglycerols. Analysis of the fatty acidradioactivity in the lipids suggests that protoplast isolationinhibited fatty acid desaturation on phosphatidylcholine andpossibly on other lipids. These results also suggest a roleof phosphatidylcholine in the donation of fatty acids for triacylglycerolsynthesis in mesophyll protoplasts. The results are discussedin terms of the regulation of lipid metabolism and protoplastbiology. (Received April 20, 1984; Accepted August 27, 1984)     

Accumulation of trans C18:1 Fatty Acids in the Rumen after Dietary Algal Supplementation Is Associated with Changes in the Butyrivibrio Community

Optimization of the fatty acid composition of ruminant milk and meat is desirable. Dietary supplementation of algae was previously shown to inhibit rumen biohydrogenation, resulting in an altered milk fatty acid profile. Bacteria involved in biohydrogenation belong to the Butyrivibrio group. This study was aimed at relating accumulation of biohydrogenation intermediates with shifts in Butyrivibrio spp. in the rumen of dairy cows. Therefore, an experiment was performed with three rumen-fistulated dairy cows receiving a concentrate containing algae (9.35 g/kg total dry matter [DM] intake) for 20 days. Supplementation of the diet with algae inhibited biohydrogenation of C_18:2 omega 6 (n-6) and C_18:3 n-3, resulting in increased concentrations of biohydrogenation intermediates, whereas C_18:0 decreased. Addition of algae increased ruminal C_18:1 trans fatty acid concentrations, mainly due to 6- and 20-fold increases in C_18:1 trans 11 (t11) and C_18:1 t10. The number of ciliates (5.37 log copies/g rumen digesta) and the composition of the ciliate community were unaffected by dietary algae. In contrast, supplementation of the diet with algae changed the composition of the bacterial community. Primers for the Butyrivibrio group, including the genera Butyrivibrio and Pseudobutyrivibrio, were specifically designed. Denaturing gradient gel electrophoresis showed community changes upon addition of algae without affecting the total amount of Butyrivibrio bacteria (7.06 log copies/g rumen DM). Clone libraries showed that algae affected noncultivated species, which cluster taxonomically between the genera Butyrivibrio and Pseudobutyrivibrio and might play a role in biohydrogenation. In addition, 20% of the clones from a randomly selected rumen sample were related to the C_18:0-producing branch, although the associated C_18:0 concentration decreased through supplementation of the diet with algae.     

微生物合成奇数链脂肪酸研究进展*

奇数链脂肪酸(odd-chain fatty acids,OCFA)在自然界分布广泛但含量低,在食品、医药健康和工业等领域有着巨大的应用潜力。目前获取OCFA的方法主要为提取法和化学合成法,但成本高、效率低,而通过微生物发酵有望实现OCFA大规模工业生产。总结OCFA的应用范围和天然合成OCFA的微生物种类,详述微生物合成OCFA的代谢途径,并从基因工程策略和发酵调控策略两方面综述目前提升OCFA产量的研究现状,旨在为利用合成生物学策略改造和提升微生物合成OCFA的能力提供较为系统的理论依据。     

Fatty Acid Compositions of Rice Lipid and their Changes during Storage

Fatty acid composition of lipids from polished rice was studied by gas chromatography on the separated fractions, fat-by-hydrolysis, neutral fat, free fatty acid and phospholipid. After six months storage, fatty acids were released from neutral fat in the same proportion as they were combined in the neutral fat.     

Lipid Classes and Fatty Acids in Ophryotrocha cyclops,a Dorvilleid from Newfoundland Aquaculture Sites

A new opportunistic annelid (Ophryotrocha cyclops) discovered on benthic substrates underneath finfish aquaculture sites in Newfoundland (NL) may be involved in the remediation of organic wastes. At those aquaculture sites, bacterial mats and O. cyclops often coexist and are used as indicators of organic enrichment. Little is known on the trophic strategies used by these annelids, including whether they might consume bacteria or other aquaculture-derived wastes. We studied the lipid and fatty acid composition of the annelids and their potential food sources (degraded flocculent organic matter, fresh fish pellets and bacterial mats) to investigate feeding relationships in these habitats and compared the lipid and fatty acid composition of annelids before and after starvation. Fish pellets were rich in lipids, mainly terrestrially derived C₁₈ fatty acids (18:1ω9, 18:2ω6, 18:3ω3), while bacterial samples were mainly composed of ω7 fatty acids, and flocculent matter appeared to be a mixture of fresh and degrading fish pellets, feces and bacteria. Ophryotrocha cyclops did not appear to store excessive amounts of lipids (13%) but showed a high concentration of ω3 and ω6 fatty acids, as well as a high proportion of the main fatty acids contained in fresh fish pellets and bacterial mats. The dorvilleids and all potential food sources differed significantly in their lipid and fatty acid composition. Interestingly, while all food sources contained low proportions of 20:5ω3 and 20:2ω6, the annelids showed high concentrations of these two fatty acids, along with 20:4ω6. A starvation period of 13 days did not result in a major decrease in total lipid content; however, microscopic observations revealed that very few visible lipid droplets remained in the gut epithelium after three months of starvation. Ophryotrocha cyclops appears well adapted to extreme environments and may rely on lipid-rich organic matter for survival and dispersal in cold environments.     

Changes in Esters of Fatty Acids of Rhizopus arrhizus During Germination and Growth

Natural esters of fatty acids of Rhizopus arrhizus Fischer increased during the first 48 hr of growth. During the 48- to 72-hr period, there was a shift in concentration from the methyl esters to the ethyl esters of fatty acids.     

Lower Inter-Partum Interval and Unhealthy Life-Style Factors Are Inversely Associated with n-3 Essential Fatty Acids Changes during Pregnancy: A Prospective Cohort with Brazilian Women

Objective

To analyze serum fatty acids concentrations during healthy pregnancy and evaluate whether socioeconomic, demographic, obstetric, nutritional, anthropometric and lifestyle factors are associated with their longitudinal changes.

Study design

A prospective cohort of 225 pregnant women was followed in the 5^th–13^th, 20^th–26^th and 30^th–36^th weeks of gestation. Serum samples were collected in each trimester of pregnancy and analyzed to determine the fatty acids composition using a high-throughput robotic direct methylation method coupled with fast gas-liquid chromatography. The independent variables comprised the subjects’ socioeconomic and demographic status, obstetric history, early pregnancy body mass index (BMI), dietary and lifestyle parameters. Analyses were performed using linear mixed-effects models.

Results

The overall absolute concentrations of fatty acids increased from the 1^st to the 2^nd trimester and slightly increased from the 2^nd to the 3^rd trimester. Early pregnancy BMI, inter-partum interval and weekly fish intake were the factors associated with changes in eicosapentaenoic + docosahexaenoic acids (EPA+DHA) and total n-3 polyunsaturated fatty acids (PUFAs). Early pregnancy BMI, age and monthly per-capita income were inversely associated with the changes in the n-6/n-3 ratio. Alcohol consumption was positively associated with the n-6/n-3 ratio.

Conclusion

Early pregnancy BMI was positively associated with EPA+DHA and total n-3 PUFAs, while presenting a reduced weekly fish intake and a lower inter-partum interval were associated with lower levels of n-3 PUFAs. A lower per-capita family income and a drinking habit were factors that were positively associated with a higher n-6/n-3 ratio.