产花生四烯酸油脂高山被孢霉干法造粒提油及菌粕的重复利用

对高产花生四烯酸油脂高山被孢霉干法造粒提油工艺中3个参数及菌粕重复利用进行研究。设计三因素四水平L16(43)正交试验,考察造粒直径、正己烷与菌粕的比例、萃取时间对提油效率及正己烷回收率的影响。结果表明:当含水率20%~25%、造粒直径1.2mm、正己烷的体积与颗粒的质量比20∶1L/g、萃取时间5h时,每克干菌体油脂得率0.5594g,正己烷的回收率达90%。与均质湿法提油相比,分别提高了17.35%和83.67%。用碱性蛋白酶及复合酶(纤维素酶、果胶酶和碱性蛋白酶)处理菌粕,以50%替代氮源(酵母膏)添加到培养基中,发酵周期分别为10d和7d。此时,生物量、油脂产量、花生四烯酸产量都达到了最大值,分别为30.33g/L、16.25g/L、8.59g/L(碱性蛋白酶处理);29.77g/L、16.89g/L、7.12g/L(复合酶处理)。其中,复合酶处理菌粕的生产强度可达4.253g/(L·d)、2.413g/(L·d)和1.017g/(L·d),与碱性蛋白酶处理相比,其生产强度分别提高了40.22%、48.49%和18.39%。干法造粒提油是有效的,且酶法处理菌粕的方法有应用前景。     

花生四烯酸油脂高产菌株的选育

以高山被孢霉为出发菌株,抗氧化剂——没食子酸辛酯为筛选剂,经过紫外-LiCl复合诱变处理,筛选出抗脂肪酸脱氢酶抑制剂的菌株。将筛选出的菌株经过摇瓶发酵复筛,筛选到1株生产性能优于出发菌株的突变株R807。与原始菌株相比,该菌株的油脂组成脂肪酸分布中C18系列脂肪酸相对较少,花生四烯酸(ARA)占总脂肪酸的含量保持在40%(质量分数)以上。其菌体生物量达到39.2 g/L,油脂产量达到16.3 g/L,ARA占总脂肪酸含量为41.72%(质量分数),ARA产量达6.81 g/L。各数值比原始菌株分别提高了22.9%、3.2%、35.1%和39.8%。连续传代多次,其产量性状无显著变化。     

高山被孢霉三阶段培养法生产花生四烯酸油脂

为提高高山被孢霉（Mortierella alpina）生物合成花生四烯酸油脂的生产效率,基于花生四烯酸油脂的积累机制,建立了一种三阶段培养法：第一阶段在全培养基中培养促进菌体生物量的快速积累,确定了60 g/L糖初始质量浓度时,最有利于生物量的快速积累;第二阶段在C源丰富而其他营养缺乏的条件下培养,促进油脂快速积累,对糖最佳初始浓度、接种时间、pH和培养时间进行了优化;第三阶段培养诱导油脂中花生四烯酸的高效积累,并确定此阶段培养时间为36 h时为最佳时间。实验结果表明：三阶段培养工艺条件下,菌体生物量、油脂量、花生四烯酸量分别为41.6、26.6和11.4 g/L,本研究相比传统分批发酵工艺在产率和花生四烯酸最终产量方面都有了显著提高。     

Influence of arachidonic acid metabolites on cardiac alpha 1-adrenoceptor responses in diabetic rats.

There is evidence that one or more metabolites of arachidonic acid can produce positive inotropic effects and may also be implicated in the enhanced alpha 1-adrenoceptor responses in hearts from diabetic rats. We therefore carried out a study to investigate the possibility that arachidonic acid metabolites could be involved in the altered cardiac alpha 1-effect of norepinephrine (in the presence of propranolol) in chronic streptozotocin-diabetic rats. Our results have shown that in the presence of the cyclooxygenase inhibitor indomethacin or the thromboxane synthetase inhibitor imidazole, the norepinephrine-stimulated positive inotropic effect and the formation of inositol 1,4,5-trisphosphate were significantly increased in control hearts but were unaltered in hearts from diabetic rats. The addition of the prostacyclin synthetase inhibitor tranylcypromine reduced the norepinephrine-stimulated positive inotropic effect and inositol 1,4,5-trisphosphate formation only in diabetic hearts and had no effect in the controls. The nature and physiological significance of the enhanced positive inotropic effect and inositol 1,4,5-trisphosphate formation in the control heart with the addition of indomethacin and imidazole are still unclear. The effect of tranylcypromine may indicate the participation of prostacyclin in mediating the enhanced alpha 1-inotropic effect of norepinephrine in the chronic diabetic heart.     

Dietary effects of bitter gourd oil on blood and liver lipids of rats.

Bitter gourd is widely used as an edible plant in Asia. In this study, we evaluated the effects of bitter gourd oil (BGO) on the blood and liver lipids of rats. Three groups of rats were given a basal diet (AIN-93G) containing 7% fat by weight. The dietary fat consisted of soybean oil (control), soybean oil + BGO (6.5:0.5, w/w; 0.5% BGO), or soybean oil + BGO (5:2, w/w; 2.0% BGO). This fat treatment gave 3.4 and 15.4% of cis(c)9,trans(t)11,t13-18:3 in the dietary fat of 0.5 and 2.0% BGO, respectively. Fatty acid analysis showed the occurrence of c9,t11-18:2 in the liver of rats fed BGO diets, whereas this conjugated linoleic acid (CLA) isomer was not detected in the liver of rats fed the control diet. Furthermore, dietary BGO decreased the concentration of 18:2n-6 and increased the concentration of 22:6n-3. The formation of the CLA isomer in the liver lipids of rats fed BGO diets could be explained by either of the following two metabolic pathways, namely, enzymatic biohydrogenation of c9,t11,t13-18:3 or enzymatic isomerization of c9,c12-18:2. The BGO diets had significantly reduced free cholesterol levels with a trend toward an increase in HDL cholesterol, but there was no significant change in the total cholesterol. The dietary BGO also affected the level of plasma hydroperoxides. A slight but significant increase in hydroperoxides was found in the rats fed 2.0% BGO. This may be attributed to the lower oxidative stability of c9,t11,t13-18:3 in BGO.     

Effect of acetaldehyde on ethanol- and aldehyde-metabolising systems of the liver and brain of rats

Lately the mechanism of craving for alcohol has been related to the local level of brain acetaldehyde occurring in ethanol consumption and depending on the activities of the brain and liver ethanol and acetaldehyde-metabolizing systems. In this connection, we studied the effect of chronic acetaldehyde intoxication on the activities of alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), the microsomal ethanol oxidizing system (MEOS) and liver and brain catalase as well as ethanol and acetaldehyde levels in the blood. The results showed that the chronic acetaldehyde intoxication did not alter significantly the activities of liver ADH, MEOS and catalase as well as liver and brain ALDH. In parallel with this, the systemic acetaldehyde administration led to shortened time of ethanol narcosis and activation of catalase in the cerebellum and left hemisphere, which may indicate involvement of this enzyme into metabolic tolerance development.     

Effect of long term feeding of rice bran oil upon lipids and lipoproteins in rats

The effects of feeding two levels of rice bran oil (RBO) on the growth, lipid parameters, and fatty acid composition of the plasma and liver of rats (Wistar strain) were compared with those produced on animals which had been fed the same levels of peanut oil (PNO). The control animals were fed synthetic diets containing 5 and 20% peanut oil (PNO) and the experimental groups were fed similar diets, containing the same level of rice bran oil (RBO). There was no significant difference with respect to the organ weights between the control and the experimental groups. In general, groups fed 20% oil gained more weight than groups fed 5% oil. The animals which received rice bran oil in their diet had, in general, comparatively lower levels of cholesterol, triglycerides and phospholipids. On the other hand, animals receiving 20% rice bran oil in their diet, showed an increase of 20% in high density lipoproteins (HDL-C), within 18 weeks (p<0.05), when compared to the animals fed with peanut oil. Similarly, low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C) were lower in RBO-fed groups, than in the PNO-fed groups. There was, however, no significant differences in the cholesterol/phospholipid (C/P) ratio of the two groups. Analysis of plasma and of liver fatty acids indicated, in a general way, the type of fat consumed. There were no significant difference in the P/S ratio, nor any in the oleic/linoleic, oleic/stearic, palmitoleic/palmitic, oleic/palmitic, and oleic/palmitoleic ratios. Furthermore, levels of saturated (SAFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids were identical in both the groups. Thus, our results suggest that feeding a high level of rice bran oil (RBO) has no deleterious effect on the growth and blood lipid profile of rats.Abbreviations PNO peanut oil - RBO rice bran oil - HDL-C high density lipoprotein cholesterol - LDL-C low density lipoprotein cholesterol - VLDL-C very low density lipoprotein cholesterol - SAFA saturated fatty acids - MUFA mono-unsaturated fatty acids     

Distribution of arachidonic and eicosapentaenoic acids in the lipids of mosses.

Lipid classes from four species of mosses, Mnium cuspidatum, and Mnium medium from Minnesota, and Hylocomium splendens and Pleurozium schreberi from Alaska, were analyzed. The total lipids of all species contained 30-40% arachidonic and eicosapentaenoic acids. However, the lipids from the Alaskan mosses contained about 75% neutral lipids (triacylglycerols, steryl esters and wax esters) whereas the lipids of the other species contained only 20% or less of these neutral lipids. Consistently, monogalactosyldiacylglycerols and phosphatidylethanol-amines were enriched in arachidonic acid and the galactolipids in eicosapentaenoic acid. The distribution of these acids in the phospholipids shows some preference for position 2. Together, the highly unsaturated C20 acids represented 80% of acyl groups in steryl esters. In triacylglycerols they were at average levels, while they were much less in sulfolipids and phosphatidylglycerols. Wax esters contained very little of the highly unsaturated acids but appreciable amounts of phytol and phytenic acid were found as wax constituents.     

Stimulation of acyl-CoA oxidase by alpha-linolenic acid-rich perilla oil lowers plasma triacylglycerol level in rats

The effect of dietary polyunsaturated fatty acids (PUFA) on hepatic peroxisomal oxidation was investigated with respect to the postprandial triacylglycerol levels. Male Sprague--Dawley rats were fed semipurified diets containing either 1% (w/w) corn oil, or 10% each of beef tallow, corn oil, perilla oil, and fish oil for 4 weeks and 4 days. Hepatic and plasma triacylglycerol levels were reduced in rats fed fish and perilla oil diets compared with corn oil and beef tallow diets. The peroxisomal beta-oxidation, catalase activity, and acyl-CoA oxidase (AOX) activity were markedly increased by fish oil feeding. To a lesser extent, perilla oil elevated AOX activity in a 4-day feeding although the effect gradually decreased in a 4-week feeding. Similarly, the mRNA levels were increased in rats fed fish and perilla oils. AOX activity was negatively correlated with postprandial triacylglycerol levels. In addition, the stimulation of AOX was highly associated with the content of long chain n-3 PUFA such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in hepatic microsome. These effects were evident within 4 days of initiating feeding. Therefore, alpha-linolenic perilla oil exerts a similar effect to fish oil in stimulating hepatic activity and gene expression of AOX by enriching long chain n-3 PUFA in hepatic membrane fraction, which can partly account for the reduction of postprandial triglyceridemia.     

The production of arachidonic acid metabolites in rat testis.

There is growing evidence that arachidonic acid is oxygenated enzymatically in every cell type and that the oxygenated metabolites regulate a variety of pathological and physiological processes including reproduction. In the present study, the metabolism of arachidonic acid in the testis via cyclooxygenase and lipoxygenase pathways was analyzed. Testicular microsomes showed substantial cyclooxygenase activity as measured by the polarographic method. Analysis of the products on TLC revealed PGF2 alpha (79.5%) as the main product followed by PGE2 (20.3%) and PGD2 (0.17%). At higher substrate concentrations (150 microM), however, 6-keto-PGF1 alpha, the stable metabolite of prostacyclin, was observed in substantial quantities. Maximum activity of lipoxygenase was observed at pH 6.4 in both microsomes and cytosol, the activity being higher in cytosol. Analysis of lipoxygenase pathway products with arachidonic acid as the substrate, revealed the presence of 12-HPETE as the major product both in cytosol and in microsomes. Besides this, 15- and 5-HPETEs were also observed in substantial quantities.     

Effect of long-chain alkylamines on arachidonate metabolism in macrophages.

The two long-chain alkylamines RO 31-4493 and RO 31-4639 inhibit in a concentration-dependent manner the zymosan-induced release of arachidonic acid, the conversion of arachidonic acid into thromboxane, prostaglandin E2 and D2 and the uptake and incorporation of exogenously added arachidonate into membrane lipids of liver macrophages. The generation of superoxide and the formation of inositol phosphates is not influenced by both agents. These results suggest a rather specific interaction of RO 31-4493 and RO 31-4639 with enzymes involved in the cellular metabolism of arachidonic acid.     

Effect of various lipoxygenase metabolites of arachidonic acid on degranulation of polymorphonuclear leukocytes

Lipoxygenase metabolites of guinea pig peritoneal polymorphonuclear leukocytes stimulated with 10 microM A23187 plus arachidonic acid were isolated and identified. These metabolites were compared with each other and to chemically synthesized arachidonate metabolites for their ability to stimulate leukocyte degranulation. 5(S),12(R)-Dihydroxy-6,8,10-(cis/trans/trans)14-cis-eicosatetraenoic acid (leukotriene B4) produced a significant release of lysozyme, but not beta-glucuronidase or beta-N-acetylglucosaminidase at low concentrations (EC50 = 6.5 x 10(-9) M), while the leukocyte nonenzymatically generated 5,12-or 5,6-dihydroxyeicosatetraenoic acids had no effect at these concentrations. Higher concentrations (1--10 microM) of all the dihydroxyeicosatetraenoic acids, 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE) and its hydroperoxy precursor stimulated significant lysozyme release which was greater than that produced by 15-hydroxy-5,8,11-13-eicosatetraenoic acid, arachidonic acid, or its acetylene analogue, 5,8,11,14-eicosatetraynoic acid. Micromolar concentrations of leukotriene B4 and 5-HETE also stimulated significant release of beta-N-acetylglucosaminidase above controls, but not beta-glucuronidase. These results suggest that leukotriene B4 may play a role in regulating the release of certain granule-bound enzymes from polymorphonuclear leukocytes.     

Antiulcerogenic effect of pentacaine, chlorpromazine and stobadine on ethanol- and indomethacin-induced stomach lesions in rats.

The aim was to compare the antiulcerogenic effect of pentacaine, chlorpromazine and stobadine on indomethacin- and ethanol-induced stomach lesions in rats. Pentacaine effectively inhibited the formation of ethanol lesions, but in the given dose and under the given experimental conditions it was ineffective against indomethacin-induced damage. Chlorpromazine and stobadine effectively inhibited indomethacin erosions, but did not affect ethanol lesions significantly. The similarity of the effect of chlorpromazine and stobadine as compared with pentacaine, in the two stomach injury models, allows the assumption that stobadine has properties typical for an indirectly acting antiulcerogenic substance. This newly discovered property of stobadine extends the possibilities of its utilization to a further set of indications.     

Cytochrome P450 and arachidonic acid bioactivation. Molecular and functional properties of the arachidonate monooxygenase

The demonstration of in vivo arachidonic acid epoxidation and omega-hydroxylation established the cytochrome P450 epoxygenase and omega/omega-1 hydroxylase as formal metabolic pathways and as members of the arachidonate metabolic cascade. The characterization of the potent biological activities associated with several of the cytochrome P450-derived eicosanoids suggested new and important functional roles for these enzymes in cellular, organ, and body physiology, including the control of vascular reactivity and systemic blood pressures. Past and current advances in cytochrome P450 biochemistry and molecular biology facilitate the characterization of cytochrome P450 isoforms responsible for tissue/organ specific arachidonic acid epoxidation and omega/omega-1 hydroxylation, and thus, the analysis of cDNA and/or gene specific functional phenotypes. The combined application of physiological, biochemical, molecular, and genetic approaches is beginning to provide new insights into the physiological and/or pathophysiological significance of these enzymes, their endogenous substrates, and products.     

Effect of excessive intake of thermally oxidized sesame oil on lipids,lipid peroxidation and antioxidants' status in rats

Fresh and thermally oxidized sesame, groundnut and coconut oils were fed to different groups of rats, as high fat diet (20%). Feeding fresh and thermally oxidized oils increased the levels of total cholesterol, low density lipoprotein cholesterol (LDL-C), and phospholipids but high density lipoprotein cholesterol (HDL-C) decreased in all the experimental animals. The levels of very low density lipoproteincholesterol (VLDL-C) and triacylglycerol increased only in groundnut and coconut oils-fed groups and decreased in sesame oil-fed group when compared with the control. When fresh and the corresponding thermally oxidized oils-fed groups were compared with the control, total cholesterol and LDL-cholesterol alone increased while triacylglycerol, VLDL-cholesterol, HDL-cholesterol, HDL/LDL ratio and phospholipids decreased. Thiobarbituric acid reacting substances increased in all the experimental animals and more so in corresponding thermally oxidized oils. It was less pronounced in sesame oil-fed groups when compared with the corresponding other oils-fed groups. Feeding of thermally oxidized oils decreased the levels of vitamin E, vitamin C and reduced glutathione when compared with fresh oils. Among the three thermally oxidized edible oils, sesame oil exhibited lesser risk for hyperlipidemic disorders.     

花生四烯酸代谢物对呼吸道感受器的作用

迷走神经与神经．免疫交互作用密切相关。在呼吸道中,迷走神经传入纤维末梢上的伤害性感受器能被多种细胞因子、炎性介质和免疫调质激活。在炎症过程中,细胞膜磷脂在磷脂酶A2作用下释放花生四烯酸（arachidonic acid,AA）,后者再经不同的酶促反应产生多种脂类代谢物。与其它的炎性介质一样,这些代谢物在炎症反应中可以激活呼吸道感受器并发挥重要作用。有些AA代谢物直接与感觉神经末梢上的受体结合,产生神经冲动并传向中枢,引起反射性效应;有些作用于感觉末梢周围的组织,改变肺的机械特性,从而刺激感觉传入神经;有些提高感觉神经末梢对机械或化学刺激的敏感性,从而增强其反应;还有些可以产生其它介质或调质而触发反射效应,或者引起炎症细胞的聚集而产生局部效应。总之,AA代谢产物有多种来源,并通过多种途径刺激呼吸道中的伤害性感受器。本综述对此进行了探讨,希望有助于阐明呼吸道炎症反应的机理。