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1.
Homogenates of semitendinosus muscle from malignant hyperthermia (MH)-susceptible pigs produced threefold more pentane than those from MH-resistant pigs, indicating enhanced free radical-mediated peroxidation of n-6 fatty acids. This did not reflect a deficiency in tissue antioxidants or antioxidant-enzymes but glutathione concentrations and glutathione peroxidase activities were increased in the tissue from MH-susceptible swine, consistent with an adaptive response to a sustained oxidant stress. A lower proportion of linoleic acid (18:2 n-6) in phospholipids and neutral lipids in muscle from MHS pigs indicated increased peroxidation or metabolism (desaturation and elongation). The increased oleic acid (18:1 n-9) in the MHS muscle indicated that desaturase activity was elevated in all lipid classes. The results are consistent with the hypothesis that enhanced free radical activity and lipid peroxidation contributes to the abnormalities in Ca2+ homeostasis and polyunsaturated fatty acid metabolism in MH.  相似文献   

2.
Based on studies in swine, the malignant hyperthermia syndrome has been postulated to result from an enhanced sensitivity (low threshold) of the Ca2(+)-induced Ca2(+)-release process. However, fatty acid production is elevated in homogenates of skeletal muscle from pigs and humans susceptible to malignant hyperthermia. In the present study, we demonstrate that the threshold of Ca2(+)-induced Ca2+ release is normal in susceptible humans and in susceptible swine depleted of triglycerides. Exogenously added unsaturated fatty acids decreased the threshold of Ca2(+)-induced Ca2+ release to a much greater extent in porcine and equine muscle than in human muscle. When triglyceride and free fatty acid values were reduced to about 40 and 60%, respectively, of control values, malignant hyperthermia-susceptible swine did not exhibit muscle rigidity when challenged in vivo with halothane and succinylcholine and the threshold of the Ca2(+)-induced Ca2(+)-release process in heavy sarcoplasmic reticulum fractions was normal. Despite the reduced triglyceride and fatty acid levels, these swine had a positive in vitro contracture test for malignant hyperthermia. A low Ca2(+)-induced Ca2(+)-release threshold is not essential for malignant hyperthermia susceptibility, but appears to be the result of excessive free fatty acids produced during organelle isolation.  相似文献   

3.
1. Skeletal muscle mitochondria of malignant hyperthermia (MH)-susceptible patients showed normal oxidative phosphorylation but were more easily uncoupled than normal by exogenous Ca2+. 2. Fatty acids, in stimulating the mitochondrial ATPase activity, are responsible for the enhanced State 4 respiration in MH-susceptible patients. 3. These results imply that skeletal muscle mitochondria and free fatty acids are associated with the development of MH syndrome.  相似文献   

4.
Although several studies have analyzed the fatty acid profile of phospholipids (PL) and, to a lesser degree, triacylglycerols (TG) in one or more tissues concurrently, a systematic comparison of the fatty acid composition of different tissues and/or lipid classes is lacking. The purpose of the present study was to compare the fatty acid composition of major lipid classes (PL and TG) in the rat serum, soleus muscle, extensor digitorum longus muscle and the heart. Lipids were extracted from these tissues and analyzed by a combination of thin-layer chromatography and gas chromatography. We found many significant differences in various tissues and lipid classes. Serum had the most distinct fatty acid profile in PL but this "uniqueness" was less apparent in TG, where differences among tissues were in general less frequent than in PL. These two skeletal muscles exhibited similar fatty acid composition in both lipid classes despite their different muscle fiber type composition, denoting that fiber type is not a major determinant of the fatty acid composition of rat skeletal muscle. The fatty acid profile of heart PL was the most different from that of the other tissues examined. PL were rich in polyunsaturated fatty acids, whereas TG were rich in monounsaturated fatty acids. Although the reasons for the differences in fatty acid profile among the tissues examined are largely unknown, it is likely that these differences have an impact upon numerous biological functions.  相似文献   

5.
A comparison of procedures to determine free fatty acids in rat heart   总被引:4,自引:0,他引:4  
The level of free fatty acids in intact tissues has been found to be low but is known to rise in proportion to the extent of autolysis. Therefore, the high levels of free fatty acid reported in the cardiac lipids of rats fed rapeseed oil were reinvestigated using two different procedures for homogenization. Quick freezing and pulverization at dry ice temperature followed by lipid extraction was found to give lower values of free fatty acids (200 microgram/g of wet heart tissue) than the more commonly used technique of employing rotating blade-type homogenizers (greater than 1700 microgram/g of wet heart tissue). The amount of diglycerides was found to be 3 times greater when the latter method was used. The high levels of free fatty acid and diglyceride suggest that extensive autolysis occurs during homogenization with a rotating blade-type homogenizer. Freezing and pulverization at dry ice temperature is therefore recommended for determining intact lipid classes in rat heart.  相似文献   

6.
The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) is the rate-limiting enzyme in the biosynthesis of cholesterol. We have studied the role of the HMGCR gene in pig lipid metabolism by means of expression and structural analysis. We describe here the complete coding region of this gene in pigs and report two synonymous single nucleotide polymorphisms in the coding region. We have, additionally, studied the association of one of these polymorphisms (HMGCR:c.807A>C) with several lipid deposition- and cholesterol-related traits in a half-sib population generated from a commercial Duroc line, showing in some families a positive relationship of HMGCR:c.807A allele with serum low-density lipoprotein (LDL)-bound cholesterol and triglyceride levels, and also with intramuscular fat (IMF) content of gluteus medius muscle. We have also assessed the expression levels in muscle and in liver from 68 Duroc individuals corresponding to the most extreme animals for the analysed traits. Liver HMGCR expression correlated negatively with the serum high-density lipoprotein (HDL) levels, carcass lean percentage and stearic acid content, while muscle expression correlated also negatively with the carcass lean percentage, stearic and linoleic acids content, but showed a positive correlation with the serum lipid cholesterol (HDL, LDL and total cholesterol), IMF and muscle oleic and palmitic fatty acid content. With this information, we have performed an association analysis of expression data with lipid metabolism phenotypic levels and the HMGCR genotype. The results indicate that HMGCR expression levels in muscle are different in the two groups of pigs with extreme values for fat deposition and total cholesterol levels, and also between animals with the different HMGCR genotypes.  相似文献   

7.
Mura  G.  Ferrara  F.  Delise  M.  Fabietti  F.  Bocca  A. 《Hydrobiologia》1997,359(1-3):229-235
Laboratory cultured fairy shrimps Branchipus pasai and Chirocephalus kerkyrensis, fed on an alga (Selenastrum capricornutum), a yeast (Saccharomyces cerevisiae) and an HUFA enriched yeast (Lansy PZ, produced by Artemia Systems, Gent, Belgium) were evaluated for their fatty acid (FA) profiles and total lipid content in order to obtain information on species differences in food conversion. The results indicate significant qualitative and quantitative differences (P < 0.001) in FA profiles both of feed and of fairy shrimp species. Among the three different diets, an appreciable lipid amount was recorded in the alga, as compared with baker‘s yeast which showed the poorest lipid content. The algal fatty acid profile showed adequate amounts of the EFA 18:2n6, 18:3n3 and20:5n3 (the most meaningful for aquacultural purposes). The enriched yeast was characterised by a considerable total lipid amount and by the presence of all the EFA. The overall amounts of fatty acids in the fairy shrimps correlated well with their levels in the feed(r > 0.9, P <0.001). An exception was noted in then-3 HUFA (highly unsaturated fatty acids) and n-6acids, among the individuals fed on yeast. Highly significant differences (P < 0.001) were also noted between the two fairy shrimp species fed on the same food type. When fed enriched yeast, both B. pasai and C. kerkyrensis profiles roughly reflected diet composition. However, when fed on algae or baker‘s yeast, the two species, though to different extents, exhibited higher EFA levels than those recorded in the food. This seems to support the existence of a partial FA bioconversion capacity in fairy shrimps previously noted in the case of the brine shrimp Artemia. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

8.
Platelets from normal and malignant hyperthermia (MH)-susceptible pigs were evaluated for differences in 45calcium uptake in the absence or presence of caffeine (2-16 mM), halothane (0.05-0.5%), or halothane and caffeine together. There were no statistically significant differences in basal or halothane-inhibited calcium uptake by platelets from either source. There was a small statistically significant difference in calcium uptake between platelets from normal and MH-susceptible pigs in the presence of 16 mM caffeine and 0.5% halothane. Calcium uptake by platelets from one pedigree of MH-susceptible pigs were stimulated in a concentration-dependent manner by caffeine. These data suggest that exposure of platelets to caffeine may have potential for identifying MH-susceptibility.  相似文献   

9.
Total lipids (TL), lipid classes, and their associated fatty acids from muscle and liver of captive and wild mature female broodstocks were investigated in order to estimate the fatty acid requirements of white seabream (Diplodus sargus). The results showed that the percentage of triacylglycerol was higher in liver and muscle of captive fish than in wild fish. The distribution of phospholipid classes in liver and muscle of both fish groups was similar, phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol being the predominant lipid classes. The general pattern of fatty acid distribution in total lipid of liver and muscle from captive and wild fish was similar. However, the relative percentage of specific fatty acids differed in captive and wild fish. The most noteworthy difference was the lower proportion of arachidonic acid (20:4n-6, AA) and the higher proportion of eicosapentaenoic acid (20:5n-3, EPA) in liver and muscle of captive fish with respect to those of wild fish. The proportion of docosahexaenoic acid (22:6n-3, DHA) did not differ between the two fish groups. The differences in EPA and AA proportions between captive and wild fish implied that captive fish presented a higher EPA/AA ratio and a lower DHA/EPA ratio than wild fish. In general terms, in both liver and muscle, the differences in fatty acid composition observed for TL were extended to all lipid classes. The results suggest that the different AA, EPA and DHA proportions in liver and muscle between captive and wild broodstocks are attributed to different levels of these fatty acids in broodstock diets.  相似文献   

10.
Malignant hyperthermia (MH) is a potentially fatal, inherited skeletal muscle disorder in humans and pigs that is caused by abnormal regulation of Ca2+ release from the sarcoplasmic reticulum (SR). MH in pigs is associated with a single mutation (Arg615Cys) in the SR ryanodine receptor (RyR) Ca2+ release channel. The way in which this mutation leads to excessive Ca2+ release is not known and is examined here. Single RyR channels from normal and MH-susceptible (MHS) pigs were examined in artificial lipid bilayers. High cytoplasmic (cis) concentrations of either Ca2+ or Mg2+ (>100 microM) inhibited channel opening less in MHS RyRs than in normal RyRs. This difference was more prominent at lower ionic strength (100 mM versus 250 mM). In 100 mM cis Cs+, half-maximum inhibition of activity occurred at approximately 100 microM Mg2+ in normal RyRs and at approximately 300 microM Mg2+ in MHS RyRs, with an average Hill coefficient of approximately 2 in both cases. The level of Mg2+ inhibition was not appreciably different in the presence of either 1 or 50 microM activating Ca2+, showing that it was not substantially influenced by competition between Mg2+ and Ca2+ for the Ca2+ activation site. Even though the absolute inhibitory levels varied widely between channels and conditions, the inhibitory effects of Ca2+ and Mg2+ were virtually identical for the same conditions in any given channel, indicating that the two cations act at the same low-affinity inhibitory site. It seems likely that at the cytoplasmic [Mg2+] in vivo (approximately 1 mM), this Ca2+/Mg2+-inhibitory site will be close to fully saturated with Mg2+ in normal RyRs, but less fully saturated in MHS RyRs. Therefore MHS RyRs should be more sensitive to any activating stimulus, which would readily account for the development of an MH episode.  相似文献   

11.
Obesity consists in fat accumulation leading to increase in adipose cells number and size. Adipocyte membrane biophysical properties are critical to maintain cellular viability in metabolically healthy obesity. This study investigated the effect of the genetic background and dietary protein restriction on fat tissue lipid composition, adipocyte membrane fluidity and water permeability using the pig as experimental model. Twenty-four male pigs from distinct genotypes, lean and obese, were fed on normal and reduced protein diets within a 2 × 2 factorial arrangement (two genotypes and two diets). Backfat thickness was twofold higher in obese than in lean pigs but unrelated to dietary protein level. In contrast, total fatty acids in the subcutaneous adipose tissue were dependent on both breed and diet, with increased lipid content promoted by the fatty genotype and by the restriction of dietary protein. Adipose membranes isolated from obese pig's subcutaneous fat tissue showed higher permeability to water, in line with an increased fluidity. Moreover, the reduced content of dietary protein influenced positively the fluidity of adipose membranes. Neither genotype nor diet affected total cholesterol concentration in the adipose membranes. Membrane-saturated fatty acids' content was influenced by genotype, while membrane-polyunsaturated fatty acids, particularly from the n-6 family, was influenced by diet. The ratio of oleic (18:1c9)/linoleic (18:2n-6) acids was positively correlated with membrane fluidity. All together, these findings reinforce the genetic background as a determinant player on adipose membrane biophysical properties and point to the dietary protein level as an important factor for subcutaneous lipid deposition as well as for regulation of membrane function, factors that may have impact on human obesity and metabolic syndrome.  相似文献   

12.
A comprehensive and systematic view of the genetic regulation of lipid metabolism genes is still lacking in pigs. Herewith, we have investigated the genetic regulation of 63 porcine genes with crucial roles in the uptake, transport, synthesis and catabolism of lipids. With this aim, we have performed an expression QTL (eQTL) scan in 104 pigs with available genotypes for the Illumina Porcine SNP60 chip and microarray measurements of gene expression in the gluteus medius muscle. Analysis of the data with gemma software revealed 13 cis‐ and 18 trans‐eQTL modulating the expression of 19 loci. Genes regulated by eQTL participated in a wide array of lipid metabolism pathways such as the β‐oxidation of fatty acids, lipid biosynthesis and lipolysis, fatty acid activation and desaturation, lipoprotein uptake, apolipoprotein assembly and cholesterol trafficking. These data provide a first picture of the genetic regulation of loci involved in porcine lipid metabolism.  相似文献   

13.
The present work was intended to analyse the chemical composition and oxidative stability of the muscle biceps femoris and adipose tissues from Iberian pigs fed different finishing diets: free-range feeding on grass and acorns in a 'Montanera' traditional system (MON), fed in confinement with a mixed diet containing high-oleic sunflower oil (115 g/kg of diet) and supplemented with 250 mg/kg α-tocopherol (HOVE), and fed in confinement with a tocopherol-non-supplemented control mixed diet (CON). Muscles from MON pigs contained significantly (P < 0.05) higher amounts of intramuscular fat than those from HOVE and CON pigs. Muscles from MON and HOVE pigs had significantly higher levels of α-tocopherol than muscles from CON pigs whereas free-range feeding provided significantly higher levels of γ-tocopherol to muscles from MON pigs than the experimental diets did to CON and HOVE pigs. Adipose tissues from MON and HOVE pigs contained significantly lower proportions of saturated fatty acids and significantly higher levels of oleic acid and monounsaturated fatty acids than those from CON pigs. Tissues from MON pigs contained significantly smaller levels of polyunsaturated fatty acids than those from CON and HOVE pigs. To a higher extent, feeding background affected the fatty acid composition of polar lipids from the muscle biceps femoris than that of neutral lipids. Tissues from MON pigs contained significantly smaller ω-6/ω-3 values than those from pigs fed mixed diets. Compared to tissues from CON pigs, those from MON and HOVE pigs exhibited a higher oxidative stability as a likely result of a most favourable fatty acid composition and the presence of higher tocopherol levels.  相似文献   

14.
Dietary lipids containing equal portions of soybean oil and fish oil were fed to juvenile Chinese soft-shelled turtle, Pelodiscus sinensis, at supplementation level of 0 to 15% for 8 weeks. Tissue fat contents of turtles increased when dietary lipid concentration increased. Fatty acid profiles for turtles fed diets supplemented with 6% or higher levels of lipids were similar to those in dietary lipids. On absolute value basis, fatty acids of 14-, 16-, and 18-carbons in muscle of turtles fed diet without lipid supplementation were higher than those in the initial turtle muscle. Among them, C16:1 and C18:1 was approximately 4 and 2 fold higher, respectively, than that of the initial turtles. By contrast, absolute amounts of C20:5 and C22:6 in muscle of turtles fed diet without lipid supplementation were slightly less than those in the initial turtles. For turtles fed lipid supplemented diets, tissue C20:5 and C22:6, however, increased when dietary lipid level increased. These results suggest that soft-shelled turtles are capable of synthesizing fatty acids up to 18 carbons from other nutrients and that they may have limited or no ability to synthesize highly unsaturated fatty acids. Lipid peroxidation measured by thiobarbituric acid-reactive substances in tissues of turtles fed 12% and 15% lipids was greater (p<0.05) than that in turtles fed 3% to 9% lipids. This could be due to high lipid and unsaturated fatty acid content in these tissues. On lipid basis, lipid peroxidation in turtles fed diet without lipid supplementation was the highest among all groups suggesting the existence of antioxidant factors in the dietary lipids.  相似文献   

15.
A comparative developmental analysis was made of lipids from wild-type and adipose60 (adp60) mutants of Drosophila melanogaster. The lipid content and fatty acid profiles of late third instar larvae, pupae, and mature adults were characterized in methanol:chloroform extracts utilizing thin layer and gas-liquid chromatography. Total lipid content of mutant adults was approximately twice that of the wild-type, but no genotypic differences in lipid content were seen in earlier developmental stages. No sexual dimorphism was observed in total lipid content, although fatty acid profiles revealed some sexual differences. Many stage-specific differences in fatty acid profiles and lipid content were developmentally associated with each genotype. Mutants tended to retain the larval phenotype in lipid content and, to a lesser extent, in fatty acid profile. In comparison to wild-type, mutants tended to have increased lipid saturation, especially in 16-carbon fatty acids in mature adults and in 18:0 fatty acids in late larvae and pupae. No significant difference between the mutants and wild-type appeared in the developmental profiles for 14:1 fatty acid isomers. Hence, adp60 does not alter the desaturation-elongation pathway, a secondary pathway for fatty acid desaturation in Drosophila, which received support from this analysis.  相似文献   

16.
This study was designed to assess the effect of ambient temperature on lipid content, lipid classes and fatty acid compositions of heart, liver, muscle and brain in oviparous lizards, Phrynocephalus przewalskii, caught in the desert area of China. Significant differences could be observed in the contents of the total lipid and fatty acid compositions among different temperatures (4, 25 and 38 degrees C). The study showed that liver and muscle were principal sites of lipid storage. Triacylglycerol (TAG) mainly deposited in the liver, while phospholipids (PL) was identified as the predominant lipid class in the muscle and brain. Palmitic and stearic acid generally occupied the higher proportion in saturated fatty acids (SFA), while monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) consisted mainly of 16:1n-7, 18:1n-9, 18:2n-6, 18:3n-3, 20:4n-6 and 22:6n-3 regardless of tissue and temperature. These predominant fatty acids proportion fluctuations caused by temperature affected directly the ratio of unsaturated to saturated fatty acids. There was a tendency to increase the degree of unsaturation in the fatty acids of TAG and PL as environmental temperature dropped from 38 to 4 degrees C, although the different extent in different tissues. These results suggested that lipid characteristics of P. przewalskii tissues examined were influenced by ambient temperature.  相似文献   

17.
Maternal and fetal plasma concentrations of free fatty acids, triacylglycerols and phospholipids and the profile of their fatty acids were measured in three catheterized and unanaesthetized sheep. Fetal concentrations of all three lipid fractions were low and did not correlate with maternal concentrations. There were no measurable umbilical venous-arterial differences. Linoleic acid concentrations were low in both mother and fetus. The fatty acid composition of fetal adipose tissue, liver, lung and cerebellum of five animals was analysed. Again linoleic acid levels were very low, but phospholipids contained 2-8% arachidonic acid. [14C] linoleic acid and [3H] palmitic acid were infused intravenously into three ewes. Only trace amounts of labelled fatty acids were found in fetal plasma and these were confined to the free fatty acids. 14C-label was incorporated into fetal tissue lipids, but most of this probably was due to fetal lipid synthesis from [14C] acetate or other water-soluble products of maternal [14C] linoleic acid catabolism. It is concluded that only trace amounts of fatty acids cross the sheep placenta. They are derived mainly from the maternal plasma free fatty acids and might just be sufficient to be the source of the small amounts of essential fatty acids found in the lamb fetus, but are insignificant in terms of energy supply or lipid storage.  相似文献   

18.
Isolation of lipid A by acid hydrolysis of Shigella flexneri lipopolysaccharide resulted in a product that consisted of a heterogeneous mixture of bands when visualized by thin layer chromatography. Differential extraction with ethyl acetate and chloroform, or extraction with EDTA, followed by chloroform-methanol-water (Bligh-Dyer extraction), or a combination of both extraction schemes, resulted in partial purification of immunologically active lipid A. Eight fractions were purified further by preparative thin layer chromatography, and each of the fractions had phosphate, carbohydrate, and esterified fatty acids. Upon incorporation into liposomes, five of the eight purified fractions reacted with anti-lipid A serum, but the three fractions with the most number of esterified fatty acids failed to react with anti-lipid A serum. At least one fraction that originally was unreactive with anti-lipid A serum became reactive as a hapten inhibitor upon removal of esterified fatty acids by alkaline hydrolysis. Alkali-treated fractions from "unreactive" and "reactive" lipid A had similar activities as hapten inhibitors. Our data suggest that lipid A can exist in multiple forms that differ by the number and placement, and possibly by the type, of fatty acids linked to the carbohydrate of lipid A. Highly acylated forms of lipid A do not react with antiserum against the unpurified lipid A mixture, but removal of fatty acids does expose immunoreactive groups.  相似文献   

19.
Peroxisome proliferator-activated receptor-alpha (PPARalpha) is a key regulator of fatty acid oxidation in skeletal muscle, but few data exist from humans in vivo. To investigate whether insulin sensitivity in skeletal muscle and body mass index (BMI) were associated with skeletal muscle expression of PPARalpha and with important genes regulating lipid metabolism in humans in vivo, we undertook hyperinsulinemic-euglycemic clamps and measured PPARalpha mRNA levels and mRNA levels of lipid regulating PPARalpha response genes in skeletal muscle biopsies. mRNA levels were measured in 16 men, using a novel highly sensitive and specific medium throughput quantitative competitive PCR that allows reproducible measurement of multiple candidate mRNAs simultaneously. mRNA levels of PPARalpha were positively correlated with mRNA levels of CD36 (r = 0.77, P = 0.001), lipoprotein lipase (r = 0.54, P = 0.024), muscle-type carnitine palmitoyltransferase-I (r = 0.54, P = 0.024), uncoupling protein-2 (r = 0.63, P = 0.008), and uncoupling protein-3 (r = 0.53, P = 0.026), but not with measures of insulin sensitivity, BMI, or GLUT4, which plays an important role in insulin-mediated glucose uptake. Thus our data suggest that in humans skeletal muscle PPARalpha expression and genes regulating lipid metabolism are tightly linked, but there was no association between both insulin sensitivity and BMI with PPARalpha expression in skeletal muscle.  相似文献   

20.
四种真菌油脂提取方法的比较研究   总被引:45,自引:0,他引:45  
采用索氏法、超临界CO2萃取法、酸热法和有机溶剂法分别提取雅致枝霉、拉曼被孢霉、少根根霉、畸雌腐霉和橙黄红酵母的油脂,从样品要求、最小样品量、仪器要求、处理样品能力及油脂得率等方面对4种提取方法进行综合评价,并对索氏法、超临界CO2萃取法和酸热法提取的雅致枝霉油脂的脂肪酸组成进行气相色谱分析。索氏法的油脂得率最高,但耗时较长;超临界CO2萃取法和酸热法的油脂得率相近,较索氏法略低,但酸热法更为简便,单位时间内样品处理能力强;有机溶剂法提取效果最差。我们建立的酸热法是一种适合油脂及多水饱和脂肪酸高产菌株筛选的简便、有效的真菌油脂提取方法。  相似文献   

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