De novo biosynthesis of prostaglandins by the Australian field cricket, Teleogryllus commodus

The accumulation and metabolism of certain polyunsaturated fatty acids by testes from the Australian field cricket, Teleogryllus commodus, are described. Testes accumulated a substantial proportion (about 16%) of label from radioactive C20:3n6 that was injected into the haemocoel. Fifty percent of the label accumulated by testes was associated with the phospholipid fraction, whereas in the remainder of the body 30% was incorporated into the phospholipid fraction. Prostaglandins (PG) E1, E2 and F2 alpha were quantified in extracts of the testes of adult insects by radioimmunoassay. Label from injected radioactive C18:2n6, C20:3n6 and C20:4n6 was recovered as prostaglandins PGE and PGF. The radioactivity from C18:2n6 that was recovered as PGE1 and PGF1 alpha indicated elongation/desaturation to C20:3n6 followed by conversion to PG. Since C18:2n6 is readily formed from acetate in T. commodus, these findings indicate the de novo biosynthesis of C20 polyunsaturated fatty acids and prostaglandins by this species.     

Quantitative association between altered plasma esterified omega-6 fatty acid proportions and psychological stress.

Medical students (MS) tested during the first year of medical school showed both greater stress on the Brief Symptom Inventory and lower plasma proportions of total esterified arachidonic acid (AA, C20:4n-6), and its omega-6 fatty acid (FA) precursor, linoleic acid (C18:2n-6) than control laboratory workers. This association suggests that omega-6 FA metabolism may be affected during stress. Low AA values might result from depletion of plasma stores for immunoregulatory prostenoids formation or from modification of metabolic pathways by cortisol or other cytokine compounds implicated in stress. Values for other major FA and the omega-3 neuronal metabolic substrate, docosahexaenoic acid (DHA, C22:6n-3) were similar between students and controls. The clear preservation of the omega-3 FA pathway suggests their programmed availability for neuronal function during stress. Since plasma FA proportions may affect immune cell membrane function(s), we suggest that altered values of plasma FAs may be an important component of the physiological effects of psychological stress.     

Arachidonic and eicosapentaenoic acids in tissues of the firefly, Photinus pyralis (Insecta: Coleoptera)

We report on the presence of high proportions of arachidonic acid (20:4n-6) and eicosapentaenoic acid (20:5n-3) in the tissue lipids of adult fireflies, Photinus pyralis. Arachidonic acid typically occurs in very small proportions in phospholipids (PLs) of terrestrial insects, ranging from no more than traces to less than 1% of PL fatty acids, while 20:5n-3 is often missing entirely from insect lipids. Contrarily, 20:4n-6 made up approximately 21% of the PL fatty acids prepared from whole males and females, and from heads and thoraces prepared from males. Proportions of 20:4n-6 associated with PLs varied among tissues, including approximately 8% for male gut epithelia, 13% for testes, and approximately 25% for light organs and body fat from males. Substantial proportions of 20:5n-3 were also associated with PLs prepared from male firefly tissues, including 5% for body fat and 8% for light organs. Because 20:4n-6 and 20:5n-3 are precursors for biosynthesis of prostaglandins and other eicosanoids, we considered the possibility that firefly tissues might produce eicosanoids at exceptionally high rates. Preliminary experiments indicated otherwise. Hence, fireflies are peculiar among terrestrial insects with respect to maintaining high proportions of PL 20:4n-6 and 20:5n-3.     

Adrenal glands and testes as steroidogenic tissue are affected by retinoylation reaction

This study was undertaken to better understand the physiological role of the retinoylation process in steroidogenic tissues. In adrenal gland mitochondria, the retinoylation extent was found equal to that of testes mitochondria but without ATP in the incubation buffer. We pointed out that the endogenous mitochondrial ATP in adrenal glands is much higher than in testes, about 1.3 x 10⁻² M and 5.2 x 10⁻⁸ M, respectively. In addition, less CoASH is required for the maximal acylation activity of the retinoyl moiety to protein(s) compared to testes. The fatty acid analysis revealed a different composition of mitochondrial membranes of these two tissues. Among the different values of fatty acids, it is important to note that adrenal glands contain a much higher amount of C18:0 and a much lower amount of C22:5 ω6 and C22:6 ω3 than testes in the mitochondrial membranes. In addition, there were also differences in arachidonic acid (ARA, C20:4 ω6) content between adrenal glands and testes mitochondria. These different values in the fatty acids composition should explain the different extent of the retinoylation process between the two organs.     

Keloids in rural black South Africans. Part 2: dietary fatty acid intake and total phospholipid fatty acid profile in the blood of keloid patients

In the second part of this study, emphasis is placed on nutritional intakes (fatty acids and micronutrients) and fatty acid intake and metabolism in the blood, respectively, according to a combined 24 h recall and standardized food frequency questionnaire analyses of keloid prone patients (n=10), compared with normal black South Africans (n=80), and total phospholipid blood (plasma and red blood cell ) analyses of keloid patients (n=20), compared with normal individuals (n=20). Lipid extraction and fractionation by standard procedures, total phospholipid (TPL) separation with thin layer chromatography, and fatty acid methyl ester analyses with gas liquid chromatography techniques were used. Since nutrition may play a role in several disease disorders, the purpose of this study was to confirm or refute a role for essential fatty acids (EFAs) in the hypothesis of keloid formations stated in part 1 of this study. (1)According to the Canadian recommendation (1991), we observed that in keloid patients linoleic acid (LA) and arachidonic acid (AA) dietary intakes, as EFAs of the omega-6-series, are higher than the recommended 7-11 g/d. However, the a-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) dietary intakes, as EFAs of the omega-3 series, are lower than the recommendation of 1.1-1.5 g/d. This was also the case in the control group, where a higher dietary intake of the omega-6 fatty acids and a slightly lower dietary intake of the omega-3 fatty acids occurred. Thus, we confirm a high dietary intake of LA (as a product of organ meats, diary products and many vegetable oils) and AA (as a product of meats and egg yolks), as well as lower dietary intakes of ALA (as a product of grains, green leafy vegetables, soy oil, rapeseed oil and linseed), and EPA and DHA (as products of marine oils). Lower micronutrient intakes than the recommended dietary allowances were observed in the keloid group that may influence EFA metabolism and/or collagen synthesis. Of cardinal importance may be the lower intake of calcium in the keloid patients that may contribute to abnormal cell signal transduction in fibroblasts and consequent collagen overproduction, and the lower copper intake that may influence the immune system, or perhaps even the high magnesium intake that stimulates metabolic activity. Micronutrient deficiencies also occurred in the diets of the normal black South Africans that served as a control group. In the case of plasma TPLs, deficiency of the omega-3 EFA series (ALA, EPA and DHA) occurred, and this is in accordance with the apparent lower omega-3 EFA intake in the diets of these patients. In the case of the red blood cell TPLs, as a true and reliable source of dietary fatty acid intake and metabolism, sufficient EFAs of the omega-6 series (LA and AA) and the omega-3 series (ALA, EPA and DHA) occurred. For this study group a relative deficiency of nutritional omega-3 EFA intake apparently did occur, but was probably compensated for by blood fatty acid metabolism.     

Astrocytes, Not Neurons, Produce Docosahexaenoic Acid (22:6ω-3) and Arachidonic Acid (20:4ω-6)

Elongated, highly polyunsaturated derivatives of linoleic acid (18:2 omega-6) and linolenic acid (18:3 omega-3) accumulate in brain, but their sites of synthesis are not fully characterized. To investigate whether neurons themselves are capable of essential fatty acid elongation and desaturation or are dependent upon the support of other brain cells, primary cultures of rat neurons and astrocytes were incubated with [1-14C] 18:2 omega-6, [1-14C]20:4 omega-6, [1-14C]18:3 omega-3, or [1-14C]20:5 omega-3 and their elongation/desaturation products determined. Neuronal cultures were routinely incapable of producing significant amounts of delta 4-desaturase products. They desaturated fatty acids very poorly at every step of the pathway, producing primarily elongation products of the 18- and 20-carbon precursors. In contrast, astrocytes actively elongated and desaturated the 18- and 20-carbon precursors. The major metabolite of 18:2 omega-6 was 20:4 omega-6, whereas the primary products from 18:3 omega-3 were 20:5 omega-3, 22:5 omega-3, and 22:6 omega-3. The majority of the long-chain fatty acids formed by astrocyte cultures, particularly 20:4 omega-6 and 22:6 omega-3, was released into the extracellular fluid. Although incapable of producing 20:4 omega-6 and 22:6 omega-3 from precursor fatty acids, neuronal cultures readily took up these fatty acids from the medium. These findings suggest that astrocytes play an important supportive role in the brain by elongating and desaturating omega-6 and omega-3 essential fatty acid precursors to 20:4 omega-6 and 22:6 omega-3, then releasing the long-chain polyunsaturated fatty acids for uptake by neurons.     

Fatty acid composition of fat body and malpighian tubules of the tenebrionid beetle, Zophobas atratus: Significance in eicosanoid-mediated physiology

Total and phospholipid fatty acid composition of fat body and Malpighian tubules from two larval stages, pupae and adults, of Zophobas atratus were analyzed. Saturated and unsaturated C16 and C18 fatty acids were major components and varied by life stage and tissue source. Eicosanoid-precursor fatty acids, including 20:3n-6, 20:4n-6 and 20:5n-3, were present in low quantities and varied by life stage and tissue source. 20:3n-6 was always present in the lowest proportions, indicating that eicosanoids derived from 20:4n-6 and 20:5n-3 (the 2- and 3-series) are likely to be of greater physiological significance in this insect. Fatty acid composition of Z. atratus fat body and Malpighian tubules was independent of diet, suggesting that this insect controls its fatty acid composition to meet the needs of individual tissues and ontogenetic constraints.     

Characteristics of fatty acid distribution is associated with colorectal cancer prognosis

To investigate tissue fatty acid distribution in relation to the incidence of colorectal cancer prognosis, adjacent normal tissue and cancerous tissue from 35 samples of clinically incident colorectal cancer were obtained. Fatty acids were measured in the colorectal mucosa phospholipid fraction by gas chromatography mass spectrometry. Palmitoleic acid and oleic acid were significantly lower in colorectal cancerous tissue, ranging from 20% to 50% less than the adjacent normal tissue. The omega-6 (n-6) fatty acid family members (20:2, 20:3, 20:4 and 22:4) were higher by 1–3 fold in cancerous colorectal tissue. Contrary with the high level of n-6 fatty acids, about a 37% to 87% reduction in EPA and DHA was observed in colorectal cancerous tissue. A higher level of linoleic acid and arachidonic acid was detected in the C cancer stage than in the B cancer stage (p<0.05), but a lower level of oleic acid and docosahexenoic acid was detected in the C cancer stage (p<0.05). The fatty acid distribution of colorectal tissue is strongly linked to the incidence of colorectal cancer. This study also provides scientific basis for identifying novel biomarkers for the diagnosis and treatment of cancer.     

De novo biosynthesis of arachidonic acid and 5,11,14-eicosatrienoic acid in the cricket Teleogryllus commodus

The de novo biosynthesis of 5,11,14-eicosatrienoic acid (5,11,14-20:3), arachidonic acid (20:4(n - 6] and eicosadienoic acid (20:2(n - 6] and the elongation/desaturation of linoleic acid (18:2(n - 6] to 20:4(n - 6) and alpha-linolenic acid (18:3(n - 3] to eicosapentaenoic acid (20:5(n - 3] were demonstrated in adult males of the field cricket Teleogryllus commodus. Sodium [1-14C]acetate, [1-14C]18:2(n - 6) and [1-14C]18:3(n - 3) were injected into adult male crickets and after an incubation period, the testes and remaining tissues were extracted and the methyl esters obtained from the phospholipid and triacylglycerol fractions were analyzed. After 5 days of daily injections of [1-14C]acetate, the methyl esters of the triene and tetraene fatty acids from the testicular phospholipid fraction were purified by AgNO3-TLC and HPLC and analyzed by GLC, radio-HPLC, and radio-GLC of ozonolysis products. The results demonstrate the de novo biosynthesis of 20:2(n - 6), 20:4(n - 6) and an isomer of 20:3(n - 6) with double bonds in the 5,11,14 positions. the elongation/desaturation of 18:2(n - 6) to 20:4(n - 6) and 18:3(n - 3) to 20:5(n - 3) was demonstrated by analysis of the methyl esters derived from the testicular phospholipid fraction by radio-HPLC after injecting crickets with radiolabeled substrates.     

The relationship between the fatty acid profiles of the yolk and the embryonic tissue lipids: A comparison between the lesser black backed gull (Larus fuscus) and the pheasant (Phasianus colchicus)

Although substantial information is available regarding the fatty acid composition of lipids of the yolk and of the developing tissues of the chicken embryo, there is little knowledge on this topic for other avian species. The aim of the present study was to compare the yolk and embryonic tissue fatty acid profiles for a species selecting its food in the wild (the lesser black backed gull) with one fed on a standard commercial diet (the commercially reared pheasant). The fatty acid compositions of the yolk lipids were determined, and major differences were observed between the two species. In particular, the phospholipid of the gull yolk was enriched in 20:4n-6 and 22:6n-3 (18.8 and 7.1%, respectively, by weight of total fatty acids) in comparison with the pheasant (4.0 and 4.1%, respectively). The fatty acid compositions of the embryonic tissues were determined using eggs incubated in the laboratory. For the liver and heart, the fatty acid composition of the lipids in the two species reflected the initial yolk composition, with the gull tissue lipids generally containing higher proportions of 20:4n-6 and 22:6n-3 than those of the pheasant. In contrast, the fatty acid profiles of the brain phospholipid were essentially identical in the two species, with 20:4n-6 and 22:6n-3 comprising approximately 9 and 17%, respectively, of total fatty acids in both cases.     

Diet fat influences liver plasma-membrane lipid composition and glucagon-stimulated adenylate cyclase activity.

Rats were fed diets that differed in fatty acid composition or in the proportion of energy derived from fat to determine if alteration of dietary fat intake influences the structural lipid composition of liver plasma membrane and the expression of an associated hormone-receptor-mediated function. Weanling rats were fed 9% (w/w) or 20% (w/w) low-erucic acid rape-seed oil or 9% (w/w) soya-bean oil for 24 days. Plasma membranes were isolated and the effect of diet fat on the fatty acid composition of phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol and sphingomyelin was determined. Diet fat significantly altered total saturated and (omega-9) and (omega-6)-unsaturated fatty acid composition in addition to the (omega-6)- to (omega-3)-unsaturated fatty acid ratio in these polar lipids. Feeding the high-fat diet increased the (omega-6)- to (omega-3)-unsaturated fatty acid ratio and the (omega-9)-unsaturated fatty acid content in all lipids except sphingomyelin. Assay of glucagon-stimulated adenylate cyclase activity at both high and low glucagon concentrations indicated that high-fat intake also decreased cyclic AMP formation. In a second experiment the fat intake was held constant (40% of energy) and oleic acid was substituted for linoleic acid by blending high- and low-linoleic acid-type safflower oils. This experiment established that a dose-response relationship exists between dietary intake of fatty acid and the fatty acid composition of plasma-membrane phospholipids. Specific diet-induced transitions in membrane phospholipid fatty acid composition were paralleled by changes in glucagon-stimulated adenylate cyclase activity. This study suggests that transitions in dietary fat intake can alter a hormone-receptor-mediated enzyme function in vivo by changing the surrounding lipid environment.     

Biosynthesis of polyunsaturated fatty acids by the australian field cricket,Teleogryllus commodus

Aspects of testicular fatty acid biochemistry from the Australian field cricket, Teleogryllus commodus, are reported. Over 10% of the phospholipid fatty acids were C20 polyunsaturated fatty acids (PUFAs), with nearly 6% arachidonic acid (20:4). The testes and ovaries accumulated a large proportion of label from radioactive arachidonic acid that was injected into the hemocoel (about 30%). Specificity in the uptake was shown by comparison to a similar study with labelled stearic acid, in which only 1.5% of the radioactivity was taken up by testes. Sixty percent of the radioactivity taken up by testes from [³H]20:4 was incorporated into phospholipids and 30% into triacylglycerols. Fat body of males and females incorporated 27% of the [³H]20:4 into phospholipids and 68% (males) or 55% (females) into triacylglcyerols. Radioactivity from [1-¹⁴C]acetate was incorporated into testicular linoleic acid and eicosatrienoic acid, but not eicosatetraenoic acid, suggesting the de novo biosynthesis of both 18:2 and a C20 PUFA by this species. Label from injected [U-¹⁴C]linoleic acid was recovered mostly as linoleic acid, with a small portion of the recovered radioactivity in eicosatrienoic acid, but not eicosatetraenoic acid. Very little label from injected linoleic acid occurred as monounsaturated or saturated fatty acids, indicating only slight, if any, β-oxidation of 18:2 to acetate and subsequent lipid synthesis.     

Synthesis of structured lipid with balanced omega-3: Omega-6 ratio by lipase-catalyzed acidolysis reaction: Optimization of reaction using response surface methodology

The present study deals with the production of structured lipid containing omega-3 and omega-6 fatty acids in the ratio of 1:1 by incorporating omega-3 fatty acids (α-linolenic acid) from linseed oil into groundnut oil using lipase (Lipozyme IM from Rhizomucor miehei) catalyzed acidolysis reaction in hexane. The reaction conditions were optimized by response surface methodology with a four-variable five-level central composite rotatable experimental design. The influence of four independent parameters, namely ratio of fatty acid concentrate from linseed to groundnut oil (0.66–1.98, w/w), reaction temperature (30–60 °C), enzyme concentration (1–5%) and reaction time (2–54 h) on omega-3 fatty acids incorporation into groundnut oil were optimized. Optimal conditions for the structured lipid containing omega-3 to omega-6 fatty acids in the ratio of 1:1 were determined to be; enzyme concentration 3.75% (w/w), temperature 37.5 °C, incubation time 30.81 h and ratio of free fatty acid concentrate from linseed oil to groundnut oil 1.16 (w/w).     

Cyclic changes in phospholipid content and composition in human endometrium during the menstrual cycle

A significant increase in total phospholipid content of the endometrium took place during the secretory phase of the human menstrual cycle (26% increase from mid-proliferative to premenstrual stage). The major phospholipid, phosphatidylcholine, was increased by 30%, whereas phosphatidylethanolamine was unchanged. Phosphatidyl-serine and -inositol underwent the largest percentage increases (40%). Phosphatidic acid levels were the only ones to decrease (-52%), a finding consistent with the role of this lipid as precursor of the increased phospholipids. The changes did not markedly affect phospholipid composition, except for a significant decrease in the proportions of phosphatidate and phosphatidylethanolamine. Arachidonate and eicosatrienoate (n-6) were the major polyunsaturated fatty acids. C22 tetra-, penta- and hexa-enoic fatty acids of the n-3 and n-4 families were also present in all major endometrial glycerophospholipids throughout the cycle. The mass changes in phospholipids during the cycle occurred without alteration of their fatty acid composition.     

Polyunsaturated fatty acids of mosquitos reared with single dietary polyunsaturates

Stock adults of Culex pipiens and tarsalis reared in crude media had a third of their phospholipid fatty acids as polyunsaturates, mainly 18C but including prominent proportions of arachidonic (20:4n6) and eicosapentaenoic (20:5n3) acids. Adults reared with synthetic media devoid of polyunsaturated fatty acids and therefore unable to fly at emergence contained no more than trace amounts of any polyunsaturate. With synthetic media containing single polyunsaturates the following findings emerged. Of four polyunsaturates known to be highly effective essential fatty acids individually 20:4n6 or 20:5n3 appeared unchanged in tissue phospholipids in proportions reflecting dietary concentrations; dietary 22:4n6 or 22:6n3 (docosahexaenoic acid) appeared also as 20:4n6 or 20:5n3, respectively, retroconverted from the administered dietary fatty acids, which were detected only in traces. Two moderately effective dietary fatty acids, 18:3n6 (γ-linolenic) and 20:3n6 (homo-γ-linolenic), which support weak flight at emergence, appeared in tissue phospholipids respectively as 18:3n6 only, or as similar proportions of 18:3n6 and 20:3n6, this latter indicating shortening to the 18C analogue as well as accumulation of the dietary 20C acid. Six other polyunsaturates [18:2n6 (linoleic), 18:3n3 (linolenic) and their 20C and 22C analogues], all considered slightly effective as essential fatty acids although unable to support proper flight, appeared in tissue phospholipid in dose-related proportions as the 18C basal n6 or n3 family analogues, with only traces of the higher analogues when these were the dietary fatty acids provided, indicating sequential chain shortening within each series, n6 or n3, no interconversion of n6 and n3 members (also shown by all other data), and efficient accumulation of the resultant 18C polyunsaturates. These findings show no capability for de novo synthesis of polyunsaturated fatty acids, afford an insight into the metabolic interrelations of diet-derived polyunsaturates and indicate a primary importance for endogenous arachidonic and eicosapentaenoic acids in mosquito essential fatty acid physiology.     

Short-term diabetes increases triacylglycerol arachidonic acid content in the rat liver

Fatty acid compositions of liver phospholipid, cholesterol ester and triacylglycerol fractions obtained from streptozotocin-induced diabetic rats were compared to those from control or from simple-acidotic rats. Significant reductions of arachidonic acid proportions in phospholipid and cholesterol ester were found on the 3rd day after the streptozotocin treatment. In triacylglycerol, arachidonic acid and the other desaturation and elongation products of linoleic acid except for gamma-linolenic acid were increased in the diabetic rats. Although essential fatty acid composition in liver phospholipid and cholesterol ester of simple-acidotic rats did not differ from control rats, dihomo-gamma-linolenic acid, arachidonic acid, adrenic acid and docosapentaenoic acid (22:5(n - 6] contents in liver TG were significantly increased over those in control rats and were similar to those in diabetic rats. These results suggest that metabolic acidosis may contribute to the fatty acid abnormalities observed in diabetic animals.     

Fatty acid compositions of Collembola: unusually high proportions of C20 polyunsaturated fatty acids in a terrestrial invertebrate

To examine the C(20) polyunsaturated fatty acid (PUFA) compositions of Collembola, we raised five species of Collembola on yeast diets, and then quantified body mass, neutral lipid fatty acid (NLFA) and phospholipid fatty acid (PLFA) compositions. PLFA content was always less than 5% of dry weight, but NLFA content varied from 5.9% to 29.6% of dry weight, depending upon species. Combined C(20) PUFA proportions of up to 9.2% and 48% were observed in the NLFA and PLFA fractions, respectively, resulting in total C(20) PUFA proportions of up to 19.4% of the total fatty acid compositions of Collembola. C(20) PUFAs were also detected in Collembola specimens from a deciduous woodland at proportions up to 29.7% of the total fatty acid composition. Terrestrial invertebrates generally contain <4% and <22% C(20) PUFAs in PLFAs and NLFAs, respectively; therefore, these results demonstrate that Collembola often possess the highest proportions of C(20) PUFAs yet observed in terrestrial invertebrates. The biochemical reasons for such high C(20) PUFA proportions, which were biosynthesised by the Collembola since these components were absent from the yeast diets, remain unclear. The distinctive fatty acid compositions of Collembola may be useful in soil food web studies utilising fatty acids as biomarkers of trophic behaviour.     

Microalgal biofactories: a promising approach towards sustainable omega-3 fatty acid production

ABSTRACT: Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) provide significant health benefits and this has led to an increased consumption as dietary supplements. Omega-3 fatty acids EPA and DHA are found in animals, transgenic plants, fungi and many microorganisms but are typically extracted from fatty fish, putting additional pressures on global fish stocks. As primary producers, many marine microalgae are rich in EPA (C20:5) and DHA (C22:6) and present a promising source of omega-3 fatty acids. Several heterotrophic microalgae have been used as biofactories for omega-3 fatty acids commercially, but a strong interest in autotrophic microalgae has emerged in recent years as microalgae are being developed as biofuel crops. This paper provides an overview of microalgal biotechnology and production platforms for the development of omega-3 fatty acids EPA and DHA. It refers to implications in current biotechnological uses of microalgae as aquaculture feed and future biofuel crops and explores potential applications of metabolic engineering and selective breeding to accumulate large amounts of omega-3 fatty acids in autotrophic microalgae.     

Fatty acids and homocysteine levels in patients with recurrent depression: an explorative pilot study

Major depressive disorders (MDD) and cardiovascular disease are mutually associated. They share signs and symptoms of the "metabolic syndrome". Two observations that may be causally related with the metabolic syndrome and therefore with both MDD and cardiovascular disease are a decrease in omega-3 polyunsaturated fatty acids (PUFAs) and a rise in plasma homocysteine (tHcy) levels. Both the rise in tHcy and the decrease in omega-3 PUFAs may be associated with enhanced lipid peroxidation. We exploratively studied 44 randomly chosen patients out of a cohort of 134 patients with the recurrent form of MDD (MDD-R). We measured tHcy levels together with saturated FAs, monounsaturated fatty acids (MUFAs) and PUFAs of the omega-3, omega-6 and omega-9 series in plasma and erythrocytes. Levels were compared with laboratory reference values. The main findings were a decrease in the erythrocytes of C22:5omega-3, C22:6omega-3, C24:1omega-9 and C20:3omega-9 and in the plasma a decrease in C24:1omega-9 and C20:3omega-9. The only significant association we found was between the total of omega-6 fatty acids and plasma tHcy. The FA alterations were found in patients although most of them were clinically recovered, suggesting that the alterations may represent a biological" trait" marker for recurrent depression.     

Phospholipid fatty acid composition, vitamin E content and susceptibility to lipid peroxidation of duck spermatozoa

Recent studies on chicken semen have suggested that the lipid and fatty acid composition of spermatozoa may be important determinants of fertility. Phospholipid fatty acid composition, vitamin E content and in vitro susceptibility to lipid peroxidation of duck spermatozoa were investigated using GC-MS and HPLC based methods. The total phospholipid fraction of duck spermatozoa was characterized by high proportions of the n-6 polyunsaturated fatty acids arachidonic (20:4n-6), docosatetraenoic (22:4n-6) and docosapentaenoic (22:5n-6) acids but a substantial proportion of the n-3 fatty acid docosahexaenoic (22:6n-3) acid was also present. Palmitic (16:0) and stearic (18:0) fatty acids were the major saturates in sperm phospholipids. Among the phospholipid classes, phosphatidylserine (PS) had the highest degree of unsaturation due to very high proportions of 22:6n-3, 22:5n-6, 22:4n-6 and 20:4n-6, comprising together more than 75% of total fatty acids in this fraction. Phosphatidylethanolamine (PE) also contained high proportions of these four C(20-22) polyunsaturates, which together formed 60% of total fatty acids in this phospholipid. Spermatozoa and seminal plasma of duck semen were characterized by unexpectedly low content of vitamin E, being more than 4-fold lower than in chicken semen. In duck semen the major proportion of the vitamin E (>70%) was located in the spermatozoa. The very high proportion of 22:6n-3 in PS and PE fractions of duck sperm lipids and the comparatively low levels of vitamin E could predispose semen to lipid peroxidation. Nevertheless the in vitro susceptibilities to Fe2+-stimulated lipid peroxidation of duck and chicken spermatozoa were very similar. The results of the study suggest that increased superoxide dismutase and glutathione peroxidase activity and increased antioxidant activity of seminal plasma may compensate for the low levels of vitamin E to help protect the membranes of duck spermatozoa, which exhibit a high degree of unsaturation from oxidative stress.