Maternal dietary FA modulate the long-chain n−3 PUFA status of chick cardiac tissue

The effect that egg yolk or maternal n−3 FA have on the cardiac tissue long-chain n−3 FA status of chicks during growth was investigated. Fggs with low, medium, and high levels of n−3 PUFA were obtained by feeding breeder hens a wheat/soybean meal-based diet containing 5% sunflower oil (Low n−3), 2.5% sunflower oil plus 2.5% fish oil (Medium n−3), or 5% fish oil (High n−3). The chicks hatched from Low, Medium, and High n−3 eggs were fed a diet containing 18∶3n−3, but devoid of long-chain n−3 FA. The FA composition of cardiac tissue was determined on days 0, 14, 28, and 42. At day 0, the cardiac FA reflected maternal diet. With time, the level of all the long-chain n−3 FA decreased compared with day 0, and this was true especially by day 14. These data show that dietary 18∶3n−3 fed to the chicks did not sustain high levels of EPA and DHA in cardiac tissue, despite the high content of long-chain n−3 FA in the maternal diet. At days 0 and 14, the chicks hatched from High and Medium n−3 eggs had higher 20∶5n−3, 22∶5n−3, and 22∶6n−3 contents with a concomitant reduction in 20∶4n−6 in the cardiac tissue compared with the Low n−3 egg group. Cardiac tissue of birds hatched from Medium n−3 eggs retained higher levels of 20∶5n−3 up to day 42 of growth when compared with other treatments (P<0.05). None of the treatments was effective in maintaining DHA levels after day 14 of growth.     

High dietary 18∶3n−3 increases the 18∶3n−3 but not the 22∶6n−3 content in the whole body, brain, skin, epididymal fat pads, and muscles of suckling rat pups

The objective of this study was to test the hypothesis that increasing maternal dietary 18∶3n−3 by decreasing the 18∶2n−6/18∶3n−3 ratio will increase the 18∶3n−3 and 22∶6n−3 content of the whole body, liver, skin (epidermis, dermis, and subcutaneous tissue), epididymal fat pads, and muscles (arms and legs) of 2-wk-old rat pups. Sprague-Dawley dams at parturition were fed semipurified diets containing either a low (18∶2n−6 to 18∶3n−3 ratio of 24.7∶1) or a high (18∶2n−6 to 18∶3n−3 ratio of 1.0∶1) 18∶3n−3 fatty acid content. During the first 2 wk of life, rat pups received only their dams' milk. Fatty acid composition of the pups' stomach contents (dams' milk), whole body, brain, liver, skin, epididymal fat pads, and muscles was determined. The stomach fatty acid composition of 18∶3n−3 reflected the dams' diet. The content of 18∶3n−3 in whole body, brain, liver, skin, epididymal fat pads, and muscles was significantly (P<0.05) greater in rat pups fed the high compared with the low 18∶3n−3 fatty acid diet. The 22∶6n−3 content of the whole body, brain, skin, epididymal fat pads, and muscles was not quantitatively different in rat pups fed either the low or high 18∶3n−3 fatty acid diet. The 20∶5n−3 and 22∶5n−3 content of the whole body, skin, and epididymal fat pads was significantly increased in rat pups fed the high compared with the low 18∶3n−3 fatty acid diet. High content of 18∶3n−3 was found in the skin of rat pups fed either a low or high 18∶3n−3 fatty acid diet. These findings demonstrate that high maternal dietary 18∶3n−3 significantly increases the 18∶3n−3 but not the 22∶6n−3 content of the whole body, brain, skin, epididymal fat pads, and muscles with approximately 39 and 41% of the whole body 18∶3n−3 content being deposited in the skin of suckling rat pups fed either the low or high 18∶3n−3 diet, respectively.     

Bioconversion of n−3 and n−6 PUFA by <Emphasis Type="Italic">Clavibacter</Emphasis> sp. ALA2

Clavibacter sp. ALA2 oxidized n−3 and n−6 PUFA into a variety of oxylipins. Structures of products converted from EPA and DHA were determined as 15,18-dihydroxy-14,17-epoxy-5(Z),8(Z),11(Z)-eicosatrienoic acid and 17,20-dihydroxy-16,19-epoxy-4(Z),7(Z),10(Z),13(Z)-docosatetraenoic acid by GC-MS and NMR analyses. In contrast, γ-linolenic acid and arachidonic acid were converted to diepoxy bicyclic FA, tetrahydrofuranyl monohydroxy FA, and trihydroxy FA. Thus, the structures of bioconversion products were different between n−3 and n−6 PUFA. Furthermore, strain ALA2 placed hydroxy groups and cyclic structures at the same position from the ω-terminal despite the number of carbons in the chain and the double bonds in the PUFA.     

Effect of 18∶1n−9, 20∶5n−3, and 22∶6n−3 on lipid accumulation and secretion by atlantic salmon hepatocytes

We have studied the effects of dietary FA on the accumulation and secretion of [³H]glycerolipids by salmon hepatocytes in culture. Atlantic salmon were fed diets supplemented with either 100% soybean oil (SO) or 100% fish oil (FO), and grew from an initial weight of 113±5 g to a final weight of 338 ±19 g. Hepatocytes were isolated from both dietary groups and incubated with [³H]glycerol in an FA-free medium; a medium supplemented with 0.75 mM of one of three FA—18∶1n−9, 20∶5n−3, or 22∶6n−3—or a medium supplemented with 0.75 mM of the sulfur-substituted FA analog tetradecylthioacetic acid (TTA), which cannot undergo β-oxidation. Incubations were allowed to proceed for 1,2,6, or 24 h. The rate of the secretion of radioactive glycerolipids with no FA added was 36% lower from hepatocytes isolated from fish fed the FO diet than it was from hepatocytes isolated from fish fed the SO diet. Hepatocytes incubated with 18∶1n−9 secreted more [³H]TAG than when incubated with no FA, whereas hepatocytes incubated with 20∶5n−3 or TTA secreted less labeled TAG than when incubated with no FA. This observation was independent of the feeding group. Hepatocytes incubated with 22∶6n−3 secreted the highest amounts of total [³H]glycerolipids compared with the other treatments, owing to increased secretion of phospholipids and mono- and diacylglycerols (MDG). In contrast, the same amounts of [³H]TAG were secreted from these cells as from cells incubated in an FA-free medium. The lipid-lowering effect of FO is thus independent of 22∶6n−3, showing that 20∶5n−3 is the FA that is responsible for the lipid-lowering effect. The ratio of TAG to MDG in lipids secreted from hepatocytes to which 20∶5n−3 or TTA had been added was lower than that in lipids secreted from hepatocytes incubated with 18∶1n−9 or 22∶6n−3, suggesting that the last step in TAG synthesis was inhibited. Morphometric measurements revealed that hepatocytes incubated with 20∶5n−3 accumulated significantly more cellular lipid than cells treated with 18∶1n−9, 22∶6n−3, TTA, or no treatment. The area occupied by mitochondria was also greater in these cells. The present study shows that dietary FO reduces TAG secretion from salmon hepatocytes and that 20∶5n−3 mediates this effect.     

Distribution of 22∶6n−3 newly synthesized from 18∶3n−3 into glycerolipid classes from tissues of rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>)

The distribution of D₅-22∶6n−3 following ingestion of a pulse of D₅-18∶3n−3 was measured quantitatively by GC-negative chemical ionization MS in lipid classes from liver, cecal mucosa, and brain from rainbow trout to further our understanding of the processes determining accretion and turnover of 22∶6n−3 in fish. The accretion of D₅-22∶6n−3 was expressed in two ways, as percent enrichment and as ng D₅-22∶6n−3/μg 22∶6n−3/mg D₅-18∶3n−3 eaten. In cecal mucosa at 2 d post-dose, PC was the most enriched lipid class followed by PE and then TAG. Enrichment fell in all lipid classes in cecal mucosa from 2 to 7 d post-dose of D₅-18∶3n−3. In liver, PC was also the most enriched lipid class at 2 d, but in this tissue all lipid classes were more enriched in D₅-22∶6n−3 by 7 d. When expressed in terms of the 22∶6n−3 content of the different lipid classes, TAG became relatively less important in cecal mucosa and more important in liver. Over a time course of 3 to 35 d, the percent enrichment of D₅-22∶6n−3 in liver peaked at 7 d in PC, PE, PS, and PI and fell rapidly in TAG from 3 d. PC from liver was the most enriched lipid class at 3 and 7 d, and thereafter PE was the most enriched lipid class. However, TAG had the highest specific activity at all times except 7 d. In brain, the enrichment of D₅-22∶6n−3 was very low in all lipid classes at 3 d and increased progressively to 35 d with PC and PE similarly enriched. TAG from brain had the highest specific activity at all times. This study is the first to present quantitative information on rates of accretion and depletion of newly synthesized 22∶6n−3 into the main lipid classes of fish tissues.     

Alteration of 20∶5n−3 and 22∶6n−3 fat contents and liver peroxisomal activities in fenofibrate-treated rainbow trout

Fish easily accumulate n−3 PUFA of exogenous origin, but the underlying mechanisms are not well established in the whole animal. This study was undertaken to investigate whether this feature was physiologically associated with mitochondrial and peroxisomal capacities that differentially affect FA oxidation. For this purpose, peroxisomal FA oxidation was increased by treating rainbow trout with fenofibrate, which strongly stimulates the peroxisome proliferator-activated receptor-α in rodents. Diets containing EPA and DHA, with or without fenofibrate added, were administered to male trout for 12 d. After treatment, neither liver hypertrophy nor accumulation of fat was apparent within the liver and muscle cells. However, fenofibrate treatment decreased the contents of EPA and DHA in the liver, white muscle, and intraperitoneal fat tissue, which represented (per whole body) at least 280 mg less than in controls. Carnitine-dependent palmitate oxidation rates, expressed per gram of liver, were slightly increased by fenofibrate when measured from tissue homogenates and were unchanged when calculated from isolated mitochondria, relative to control fish. The treatment altered neither carnitine palmitoyltransferase I activity rates, expressed per gram of liver, nor the sensitivity of the enzyme to malonyl-CoA inhibition, but did increase the malonyl-CoA content (+45%). Meanwhile, fenofibrate increased (by about 30%) the peroxisome-related activities, i.e, catalase, carnitine-independent palmitate oxidation, acyl-CoA oxidase, and the peroxisomal FA-oxidizing system, relative to the control group. The data strongly suggest that the induction of peroxisomal activities, some of which being able to oxidize very long chain FA, was responsible for the lower contents of EPA and DHA in the body lipids of fenofibrate-treated trout.     

Effects of dietary supplementation of rapeseed oil on metabolism of [1-<Superscript>14</Superscript>C]18∶1n−9, [1-<Superscript>14</Superscript>C]20∶3n−6, and [1-<Superscript>14</Superscript>C]20∶4n−3 in atlantic salmon heaptocytes

Atlantic salmon were fed fish meal-based diets supplemented with either 100% fish oil (FO) or 100% rapeseed oil (RO) from an initial weight of 85 g to a final average weight of 280 g. The effects of these diets on the capacity of Atlantic salmon hepatocytes to elogate, desaturate, and esterify [1-¹⁴C]18∶1n−9 and the immediate substrates for the Δ⁵ desaturase, [1-¹⁴C]20∶3 n−6 and [1-¹⁴C]20∶4n−3, were investigated. Radiolabeled 18∶1n−9 was mainly esterified into cellular TAG, whereas the more polyunsaturated FA, [1-¹⁴C]20∶3n−6 and [1-¹⁴C]20∶4n−3, were primarily esterified into cellular PL. More of the elongation product, [1-¹⁴C]20∶1n−9, was produced from 18∶1n−9 and more of the desaturation and elongation products, 22∶5n−6 and 22∶6n−3, were produced from [1-¹⁴C]20∶3n−6 and [1-¹⁴C]20∶4n−3, respectively, in RO hepatocytes than in FO hepatocytes. Further, we studied whether increased addition of [1-¹⁴C]18∶1n−9 to the hepatocyte culture media would affect the capacity of hepatocytes to oxidize 18∶1n−9 to acid-soluble products and CO₂. An increase in exogenous concentration of 18∶1n−9 from 7 to 100 μM resulted in a nearly twofold increase in the amount of 18∶1n−9 that was oxidized. The conversion of 20∶4n−3 and 20∶3n−6 to the longer-chain 22∶6n−3 and 22∶5n−6 was enhanced by RO feeding in Atlantic salmon hepatocytes. The increased capacity of RO hepatocytes to produce 22∶6n−3 was, however, not enought to achieve the levels found in FO hepatocytes. Our data further showed that there were no differences in the hepatocyte FA oxidation capacity and the lipid deposition of carcass and liver between the two groups.     

Tissue deposition of n−3 FA pathway intermediates in the synthesis of DHA in rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>)

The tissue distribution of newly synthesized 22∶6n-3 and intermediate PUFA was examined in rainbow trout to further our understanding of the metabolism of this EFA in fish. Rainbow trout were fed a pulse of deuterated linoleic acid (D₅−17,17,18,18,18−18∶3n-3), and the tissue distribution of deuterated anabolites was determined at interval up to 35 d post-dose by GC-negative chemical ionization MS of the pentafluorobenzyl derivatives. D₅−22∶6n-3 was the major deuterated FA in liver and cecal mucosa 2 and 5 d post-dose. All the n−3 FA pathway intermediates were found in liver, cecal mucosa, and blood including D₅−24∶5n-3 and D₅−24∶6n-3. Brain and eyes also contained the full suite of intermediate deuterated FA, but with a different profile from liver when analyzed over a longer time course up to 35 d. D₅−20∶5n-3 was the major component in brain up to 7 d, after which D₅−22∶6n-3 became predominant, but D₅−22∶5n-3 constituted ca. 20% of FA throughout the time period. The pattern in eyes was similar but less pronounced. In visceral adipose tissue there was a much greater accumulation of the initial substrate, D₅−18∶3n-3, with D₅−18∶4n-3 and D₅−22∶6n-3 the predominant deuterated FA at all time points. There was a similar though less pronounced trend in eye socket adipose tissue. The C₂₄ PUFA were not detected in visceral fat and barely detected in eye socket fat. The results show that the kinetics of accumulation and depletion of the various n−3 PUFA differ between tissues. The presence of pathway intermediate FA provides evidence that liver and ceca possess the full metabolic pathway for synthesis of 22∶6n-3, whereas brain and eyes are less active, with an accumulation of pentaene intermediate FA, and adipose tissue is inactive.     

Pyloric ceca are significant sites of newly synthesized 22∶6n−3 in rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>)

In this pulse-chase study, rainbow trout fed a diet containing deuterated (D₅) (17,17,18,18,18)-18∶3n−3 ethyl ester accumulated D₅-22∶6n−3 in pyloric ceca to a greater extent than in liver 2 d post-dose. The ratio of newly synthesized D₅-22∶6n−3 in ceca to that in liver 2 d after feeding D₅-18∶3n−3 was 4.7±1.2 when expressed as per mg tissue and 5.2±2.4 when expressed as per mg protein. The amount of D₅-22∶6n−3 in ceca then declined whereas that in liver and blood increased, with the ratio of ceca to liver falling to 1.7 and 1.4, respectively, by day 5 and approaching unity by day 9. A crude cecal mucosa fraction contained 123±50 ng D₅-22∶6n−3/mg protein/mg D₅-18∶3n−3 eaten 2 d after feeding the tracer, compared with 35±21 ng D₅-22∶6n−3/mg protein/mg D₅-18∶3n−3 eaten in liver. Three days later the amount in cecal mucosa had fallen by one-third and that in liver had increased threefold. Most of the D₅-18∶3n−3 was catabolized very rapidly. The ratio of D₅-18∶3n−3 to 21∶4n−6 (a relatively inert FA marker) in the diet was 4.0, but this fell to 0.30 in ceca and ca. 0.8 in liver, blood, and whole carcass one day after feeding. These results indicate that ceca are active in the synthesis of 22∶6n−3 and the oxidation of 18∶3n−3.     

Electrochemical properties of LiNi<Subscript>1−<Emphasis Type="Italic">y</Emphasis></Subscript>M<Subscript><Emphasis Type="Italic">y</Emphasis></Subscript>O<Subscript>2</Subscript> (M=Ni,Ga, Al and/or Ti) cathodes synthesized by the combustion method

LiNiO₂, LiNi_0.995Al_0.005O₂, LiNi_0.975Ga_0.025O₂, LiNi_0.990Ti_0.010O₂ and LiNi_0.990Al_0.005Ti_0.005O₂ were synthesized by preheating at 400 °C for 30 min in air and calcination at 750 °C for 36 h in an O₂ stream with excess lithium amount z = 0.10 in Li_1+z Ni_1−y M _y O₂. For these samples, the discharge capacities and discharge capacity degradation rate are compared. LiNiO₂ has the largest discharge capacity at the 20th cycle (n = 20) and the 50th cycle (n = 50). LiNiO₂ and LiNi_0.995Al_0.005O₂ have relatively good cycling performances and their discharge capacities at n = 50 are 134 and 123 mAh/g, respectively, at 0.1 C rate. The crystallite sizes and strains were calculated by the Williamson–Hall method with XRD patterns and compared for the samples as prepared and after 50 charge–discharge cycles.     

Effect of Coordination Modes of HL Ligand on the Molecular Architecture of Its Transition Metal Complexes (HL = 5-Methyl-2-Phenyl-4-[(2-<Emphasis Type="Italic">o</Emphasis>-Tolylamino)-Phenylmethylene]pyrazol-3(2H)-one)

Abstract  Two Ag⁺ complexes [Ag(HL)₂(PF₆)] (1) and [(AgL) _n  · n(CH₂Cl₂) · n(0.5H₂O)] (2) (HL = 5-methyl-2-phenyl-4-[(2-o-tolylamino)-phenylmethylene]pyrazol-3(2H)-one) were synthesized and structurally characterized by EA analysis, IR spectra and X-ray crystallography. The result shows that two expected coordination modes (Modes I and III in Scheme 1) of the HL ligand, can be observed in its Ag⁺ complexes, while not in other transition metal ions (Ni²⁺, Co²⁺ or Cu²⁺) complexes whether deprotonation or not for the HL ligand. Graphical Abstract  Three possible coordination modes (Modes I, II or III in Scheme 1) of the selected HL (HL = 5-methyl-2-phenyl-4-[(2-o-tolylamino)-phenylmethylene]pyrazol-3(2H)-one) ligand, can be adopted, in which Modes I and III can be observed in its two Ag⁺ complexes [Ag(HL)₂(PF₆)](1) and [(AgL) _n  · n(CH₂Cl₂) · n(0.5H₂O)] (2), while Mode II just observed in its transition metal ions (Cu²⁺, Ni²⁺, or Co²⁺) complexes, resulting from the deprotonatd form of the HL ligand and the coordination characters of transition metal ions.      

The redox pair {(μ4-TCNE)[Fe(CO)2(C5H5)]4}4+/3+: Surprisingly small metal–ligand interaction and the first resolved EPR hyperfine structure (13C, 14N, 57Fe) of a tetranuclear complex with TCNE−

Electrochemistry and absorption spectroscopy (UV/Vis, IR) of the complex {(μ₄-TCNE)[Fe(CO)₂(C₅H₅)]₄}(BF₄)₄ reveal only a small degree of metal-to-ligand π back donation, in contrast to previously characterized compounds [(TCNE)(ML_n)₄]. Accordingly, the one-electron reduced {(μ₄-TCNE)[Fe(CO)₂(C₅H₅)]₄}³⁺ exhibits a very well resolved EPR spectrum at g = 1.9965 with detectable coupling of 0.055 mT for ⁵⁷Fe in natural abundance from four coordinated [Fe(CO)₂(C₅H₅)]⁺ groups.