Eicosapentaenoic acid代谢产物促进胰岛α细胞转分化为胰岛β细胞的作用研究

目的 探讨eicosapentaenoic acid(EPA)代谢产物促进胰岛α细胞向β细胞转分化的作用。方法 雄性C57BL/6J小鼠连续5 d腹腔注射60 mg/kg链脲佐霉素(streptozocin, STZ)构建1型糖尿病(T1DM)小鼠模型,2周后随机分为模型组、97%EPA饮食干预组、75%鱼油(50%EPA+25%DHA)饮食干预组,每周检测随机血糖;模型到期后,通过免疫荧光染色观察小鼠胰腺中胰岛β细胞再生情况。提取tdTomato荧光蛋白特意标记α细胞的小鼠(GCGicre小鼠与Rosa26tdTomato小鼠杂交获得)胰岛,加入1 mmol·L^(-1)STZ诱导β细胞凋亡,添加EPA代谢产物,培养48 h后,利用荧光染色观察胰岛素和tdTomato荧光的表达。在小鼠胰岛α细胞系αTC1培养基中添加EPA代谢产物,48 h后,利用荧光染色观察胰岛素和胰高血糖素的表达。结果 EPA和鱼油饮食干预均可明显降低T1DM小鼠的血糖水平,改善葡萄糖稳态,且胰腺中出现胰岛素和胰高血糖素共定位细胞;EPA代谢产物引起已发生β细胞凋亡的小鼠胰岛中发生tdTomato荧光蛋白和胰岛素共定位;EPA代谢产物可促进胰岛αTC1细胞系细胞分泌胰岛素。结论 EPA及其代谢产物可通过促进胰岛α细胞转分化为β细胞,进而增加胰岛素的分泌,缓解T1DM小鼠的高血糖症状。

Fatty Acid Treatment with Pure Omega-3 Eicosapentaenoic Acid Ethyl Ester for Patients with Cardiovascular Diseases: Differences between Branded (EPADEL®) and Generic Products

Background: Omega-3 polyunsaturated fatty acids (PUFAs) have some protective benefits for patients with coronary artery and cerebrovascular diseases. Eicosapentaenoic acid (EPA) drugs are prescribed as branded (B: EPADEL?) or generic products but no data exist concerning the differences in treatment outcomes between these products. Methods and Results: We investigated the differences in the serum levels of EPA, docosahexaenoic acid (DHA) and arachidonic acid (AA), and the EPA/AA ratios through blood sampling six months after daily administration of 1800 mg of EPADEL? and a generic EPA drug was initiated for 96 patients with cardiovascular diseases. All patients received these PUFA treatments while continuing with baseline therapy. After 6 months of administration, EPADEL? produced better results than the generic (G) product (EPA;baseline: 59.4 ± 25.5 μg, B: 215.5 ± 58.8 μg, G: 199.7 ± 63.8 μg, B vs G, p < 0.0005;AA;baseline: 197.4 ± 44.6 μg, B: 158.3 ± 36.3 μg, G: 163.6 ± 38.9 μg, B vs G, p < 0.02, as mean ± SD). Conclusions: There were clear differences between EPA branded and the generic products. Further study is required to determine whether the benefits from the branded product justify the higher price compared to the generic drug cost.

Fatty Acid Composition and Digestive Enzyme Activities of Rainbow Trout in Response to Dietary Docosahexaenoic Acid(DHA)and Eicosapentaenoic Acid(EPA)During Salinity Acclimation

This physiological study aimed to evaluate the effects of dietary docosahexaenoic acid(DHA)and eicosapentaenoic acid(EPA)on the fatty acid composition and digestive enzyme activities of rainbow trout(Oncorhynchus mykiss)during salinity acclimation.Rainbow trout with an average initial weight of 90.61 g±9.25 g were fed diets with the quantities of DHA and EPA equaling to 0.54%,0.95%,1.40%and 1.79%(abbreviated as DE-0.54,DE-0.95,DE-1.40,and DE-1.79,respectively)for eight weeks,after which the gastric and intestinal fatty acids composition were analyzed.Subsequently,the fish underwent salinity acclimation.On days 1,4,7,and 14 after the freshwater was replaced by seawater and at the end of the 8-week period,gastric and intestinal digestive enzyme activities were determined.The results showed that the gastric and intestinal DHA and EPA contents of the fish were positively correlated to their dietary DHA and EPA levels.Low dietary DHA and EPA levels inhibited the protease activity of rainbow trout.Fish in the DE-0.54 group increased the lipase activity to enhance the utilization of lipids maybe due to the inadequate essential fatty acids for fish in this group.Hence,rainbow trout in the DE-0.54 group failed to maintain suitable activities of digestive enzymes after salinity acclimation.Therefore,a diet with minimum 0.95%DHA and EPA levels is necessary for rainbow trout during salinity acclimation.

Effects of Nutritional Factors on the Growth and Heterotrophic Eicosapentaenoic Acid Production of Diatom Nitzschia laevis

The effects of several nutritional factors on the growth and eicosapentaenoic acid （EPA） production of diatom Nitzschia laevis were studied. 4LDM （quadrupled concentration of the nutrient salt） was the optimal concentration of nutrient salt for the growth and EPA production ofN. laevis. The growth ofN. laevis was inhibited when the glucose concentration was either lower than 10gL^-1 or higher than 15 gL^-1. Both sodium nitrate and urea were good nitrogen sources for the growth and EPA production, while ammonium chloride seriously decreased the dry cell weight （DW） and the EPA content. Silicate seriously influenced the growth of N. laevis. The maximum DW of 2.34 gL^-1 was obtained in the presence of 150 mgL^-1 Na2SiO3· 9H2O. The EPA content remained almost the same when the silicate concentration was lower than 150mgL^-1; however, higher silicate concentrations resulted in a steady decrease of EPA content. Low medium salinity （≤29） did not seem to influence the DW of N. laevis, and high salinity resulted in a decrease of DW. The highest EPA content （4.08%） and yield （110mgL^-1） were observed at the salinity of 36 and 29, respectively. Key words polyunsaturated fatty acid; eicosapentaenoic acid; microalga; Nitzschia laevis; heterotrophy

Effect of eicosapentaenoic acid on regional arterial stiffness:Assessment by tissue Doppler imaging

AIM: To evaluate the effects of eicosapentaenoic acid (EPA) on regional arterial stiffness assessed by strain rate using tissue Doppler imaging. METHODS: Nineteen eligible patients were prospectively studied (mean age 62 ± 8 years, 68% men). Subjects with large vessel complications and/or diabetes mellitus were excluded. The strain rate of the ascending aorta was measured by tissue Doppler imaging as an index of regional arterial stiffness, and brachial-ankle pulse wave velocity (baPWV) was measured as an index of degree of systemic arteriosclerosis. These indices were compared before and after administration of EPA at 1800 mg/d for one year. RESULTS: The plasma concentration of EPA increased significantly after EPA administration (3.0% ± 1.1% to 8.5% ± 2.9%, P < 0.001). There were no significant changes in baPWV (1765 ± 335 cm/s to 1745 ± 374 cm/s), low-density lipoprotein cholesterol levels (114 ± 29 mg/dL to 108 ± 28 mg/dL), or systolic blood pressure (131 ± 16 mmHg to 130 ± 13 mmHg) before and after EPA administration. In contrast, the strain rate was significantly increased by administration of EPA (19.2 ± 5.6 s-1, 23.0 ± 6.6 s-1, P < 0.05). CONCLUSION: One year of administration of EPA resulted in an improvement in regional arterial stiffness which was independent of blood pressure or serum cholesterol levels.

Solid Dose Form of Metformin with Ethyl Eicosapentaenoic Acid Does Not Improve Metformin Plasma Availability

Background: The purpose of the study was to investigate effects of ethyl eicosapentaenoic acid on pharmacokinetics of metformin. Pharmacokinetic profiles of metformin and ethyl eicosapentaenoic acid when delivered separately or together in solid dose form were investigated and compared to determine whether the solid dose resulted in an altered metforminpharmacokinetics when given with or without food. Methods: A single-center, open-label, repeated dose study investigated the pharmacokinetic (PK) profile of metformin when administered in solid dose form with ethyl eicosapentaenoic acid compared to co-administration with icosapent ethyl, an ester of eicosapentaenoic acid and ethyl alcohol used to treat severe hypertriglyceridemia with metformin hydrochloride. Non-compartmental PK methods were used to compare area under the plasma concentration curve (AUC) and maximum plasma concentration (Cmax) between patients randomized to either the ester or separate medications group under both fasting and fed conditions. Results: Using these two PK parameters, results showed that metformin availability was higher under fasting conditions when delivered separately from icosapent ethyl. There were no group differences in the fed condition. Conclusions: The solid dose form of metformin and ethyl eicosapentaenoic acid did not improve the pharmacokinetics of metformin in terms of plasma availability, suggesting that little is to be gained over the separate administration of ethyl eicosapentaenoic acid and metformin hydrochloride.

Effects of Temperature, Salinity, Light Intensity, and pH on the Eicosapentaenoic Acid Production of Pinguiococcus pyrenoidosus

The effects of temperature, light intensity, salinity, and initial pH on the growth and fatty acid composition of Pinguiococcus pyrenoidosus 2078 were studied for eicosapentaenoic acid (EPA) production potential. The fatty acid composition was assayed by gas chromatography-mass spectrometry, which indicated that the main fatty acids were C14:0, C16:0 and EPA. The highest EPA percentage 20.83% of total fatty acids was obtained at 20℃ with the temperature being set at 20, 24, and 28℃. Under different salinities and light intensities, the highest percentages of total polyunsaturated fatty acids (PUFAs) and EPA were 17.82% and 31.37% of total fatty acids, respectively, which were achieved at salinity 30 and 100μmol photon m-2s-1 illumination. The highest percentages of total PUFAs and EPA were 38.75% and 23.13% of total fatty acids, respectively, which were reached at an initial pH of 6 with the test range being from 5.0 to 9.0.

Preparation of DHA-and EPA-enriched Glycerides by Enzymatic Interesterification Using Tuna Oil and Capric Acid

This study focused on the preparation of docosahexaenoic acid(DHA) and eicosapentaenoic acid(EPA)enriched-triacylglycerols by enzymatic interesterification using tuna oil and capric acid. The content of DHA+EPA is 26.86% in the tuna oil used in this study. A response surface methodology(RSM) was used to optimize the reaction parameters(reaction temperature, substrate molar ratio, enzyme amount and reaction time), and the optimized conditions were determined to be: reaction temperature 58℃, substrate molar ratio(capric acid : tuna oil) 4:1, enzyme amount 4%, and reaction time 7.5 h. Under the optimized conditions, the content of DHA+EPA in the glycerides was 40.03%, which is 13.17% higher than that in raw tuna oil. In addition,the MLM-type structured lipids containing medium chain fatty acids(capric acid) at positions sn-1,3 and a long chain fatty acid(DHA/EPA) at the position sn-2 may have many health benefits for humans.

Optimization of High EPA Structured Phospholipids Synthesis from （u-3 Fatty Acid Enriched Oil and Soy Lecithin

The molecular structure of phospholipids can be changed enzymatically to obtain different tailor-made phospholipids. Incorporation of ω-3 fatty acids into phospholipids structure increased their oxidative stability, suggesting more health beneficial phospholipids. This study aimed to optimize eicosapentaenoic acid （EPA） incorporation into phospholipids structure by acidolysis reaction using free lipase （EC 3.1.1.3） from Rhizomucor miehei. Deoiled soy lecithin from anjasmoro variety was used as phospholipids source, while ω-3 fatty acid enriched oil was used as acyl source. Oil enriched with ω-3 fatty acids was obtained from low temperature solvent crystallization of lemuru （Sardinella longiceps） by-product. Response surface methodology （RSM） was used in this study to determine the relationship between the three factors （enzyme concentration, reaction time and substrate ratio） and their effects on EPA incorporation into soy lecithin structure. The results showed that the relation between EPA content with three factors （reaction time, enzyme concentration and substrate ratio） was quadratic. The significant factors were substrate ratio and reaction time. Optimum conditions at a ratio of 3.77：1 between ω-3 fatty acids enriched oil and soy lecithin, 30% lipase concentration, and 24.08 h reaction time, gave 22.81% of EPA content of structured phospholipids.

Research on Arachidonic Acid and Eicosapentaenoic Acid Anabolic Metabolism in Diasporangium sp.

The fatty acids of a strain of Diasporangium sp.had been analyzed by using GC-MS.The fatty acids of twenty mutants were determined.Based on these results,the producing of eicosapentaenoic acid(EPA)supposed via 18∶2,18∶3,20∶3,20∶4 which all belong to ω-6 fatty acids.The ω-3 desaturation was undertaken at arachidonic acid(AA).In addition,mutant strains resulted in enhanced content of AA which could get two times more than initial strain,but no compact on EPA.

The effects of EPA + DHA and aspirin on inflammatory cytokines and angiogenesis factors

Objective: In a recent study, we showed that the combination of aspirin plus the ω3 fatty acids eicosapen-taenoic acid (EPA) and docosahexaenoic acid (DHA) synergistically inhibited platelet function. As aspirin, EPA, and DHA have demonstrated anti-inflammatory properties, we hypothesized that the ingestion of EPA and DHA, with and without aspirin, would reduce plasma levels of inflammatory cytokines and angiogenesis factors more than aspirin alone and before aspirin was ingested. Methods: Using multiplex technology, we investigated the effects of aspirin (single-dose 650 mg on day 1), EPA + DHA (3.4 g/d for days 2 - 29), and aspirin with EPA + DHA (day 30) on plasma levels of inflammatory cytokines and angiogenesis factors in healthy adults. Results: Aspirin alone had no effect on any factor versus baseline, but EPA + DHA, with and without aspirin, significantly reduced concentrations of 8 of 9 factors. Although EPA + DHA plus aspirin reduced concentrations of a subset of the factors compared to baseline, neither aspirin alone nor the combination significantly reduced the level of any analyte more robustly than EPA + DHA alone. Conclusions: These data suggest that EPA + DHA has more pronounced down-regulatory effects on inflammation and angiogenesis than aspirin. The implications of these findings for the use of combined therapy for cardiovascular disease remain to be clarified.

富里酸诱导对三角褐指藻EPA合成积累的影响

探究不同富里酸质量浓度对三角褐指藻二十碳五烯酸(EPA)合成积累的影响。结果表明,在质量浓度20 mg/L富里酸诱导下,三角褐指藻EPA含量和产量均达到最大值,为19.81 g/100 g和738.91 mg/L,较无富里酸诱导EPA含量和产量分别提高1.12和1.50倍。外源富里酸作用提高了三角褐指藻胞内过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的酶活,使色素(叶绿素、类胡萝卜素)和总多酚抗氧化组分比例增加,活性氧(ROS)和丙二醛(MDA)水平降低,整体抗氧化能力获得显著提升,有效阻抑EPA的氧化分解;富里酸作用同时还上调了EPA合成通路去饱和酶(Δ^(5)-FADS、Δ^(6)-FADS、Δ^(12)-FADS、Δ^(15)-FADS、Δ^(17)-FADS)和延长酶(Δ^(6)-ELOVL)等系列关键酶,使其上调表达量较无富里酸作用分别增加0.33、0.94、0.33、0.58、1.15和0.70倍,为EPA高效合成积累提供前驱物和能量。

通过综合网络信息方法深入了解EPA治疗ANCA相关血管炎的分子机制

目的通过网络药理学和分子对接的研究方法预测二十碳五烯酸(EPA)辅助治疗ANCA相关性血管炎(AAV)的分子作用机制。方法通过PubChem获取EPA的三维结构和相应的结构式,在STITCH、Swiss Target Prediction、Pharmmapper和CTD数据库获取药效团预测靶点,并将获取药效团预测靶点并与GeneCards、OMIM和Disgenet数据库获取的AAV疾病靶点做交集,得到关键靶点,运用STRING数据库和Cytoscape软件构建蛋白互作网络;对有效靶点进行GO分析及KEGG相关通路的富集分析;通过Autodock对成分靶点进行分子对接验证。结果获得116个EPA治疗AAV潜在作用靶点,关键靶点包括TNF,IL6,ALB,TP53,IL1β,MAPK3,CASP3,PTGS2,PPARG,CCL2等。GO富集分析有1503个GO术语(P<0.05),KEGG中有1503个信号通路(P<0.05)主要富集在癌症、脂质和动脉硬化、TNF信号传导途径、神经变性的途径——多种疾病和IL-17信号传导途径等多个信号通路。分子对接结果发现EPA与免疫炎症、细胞凋亡及脂质代谢相关目标靶点能很好结合。结论本研究初步揭示了EPA治疗AAV的潜在靶点、涉及的生物过程及信号通路,为进一步研究奠定了基础。

EPA对P.gingivalis LPS诱导人牙周膜成纤维细胞炎症反应的影响

目的:分析二十碳五烯酸(eicosapntemacnioc acid,EPA)对牙龈卟啉单胞菌(Porphyromonas gingivalis,P.gingivalis)脂多糖(lipopolysaccharides,LPS)诱导人牙周膜成纤维细胞(human periodontal ligament cells,hPDLCs)分泌炎症因子的作用。方法:利用组织块法培养hPDLCs,MTT法检测不同浓度EPA对hPDLCs细胞活性的影响。根据MTT结果选择合适的EPA浓度,分别采用实时定量PCR和ELISA法检测EPA对P.gingivalis LPS诱导hPDLCs分泌白细胞介素6(Interleukin-6,IL-6)、IL-8和IL-1β能力的影响,采用SPSS 10.0软件包对数据进行统计学分析。结果:25~100μmol/L EPA对hPDLCs细胞活性无影响,但可呈剂量依赖性下调P.gingivalis LPS诱导hPDLCs分泌IL-6、IL-8和IL-1β的能力。结论:EPA有望在不影响细胞活性的情况下,抑制P.gingivalis LPS诱导hPDLCs分泌炎症因子的能力,EPA可能成为牙周炎抗炎治疗的潜在靶点。

Diet switch and omega-3 hydroxy-fatty acids display differential hepatoprotective effects in an obesity/nonalcoholic fatty liver disease model in mice

AIM To study the effect of 18-hydroxy-eicosapentaenoic acid(18-HEPE) and 17-hydroxy-docosahexaenoic acid(17-HDHA) in a murine model of obesity/nonalcoholic fatty liver disease.METHODS C57 BL/6 mice were fed with standard chow diet(CD) or high-fat, fructose-enriched diet(HFD) for 16 wk. Then, three groups were treated for 14 d with either, diet switch(HFD for CD), 18-HEPE, or 17-HDHA. Weightand fasting glucose were recorded on a weekly basis. Insulin tolerance test was performed at the end of treatment. Histological analysis(HE and Masson's trichrome stain) and determination of serum insulin, glucagon, glucagon-like peptide 1(GLP-1), glucose-dependent insulinotropic polypeptide, adiponectin and resistin were carried out as well as liver proteins by western blot.RESULTS Mice treated with hydroxy-fatty acids 18-HEPE and 17-HDHA displayed no weight loss or improved insulin sensitivity. However, these mice groups showed a significant amelioration on serum GLP-1, adiponectin and resistin levels. Also, a significant reduction on inflammatory infiltrate was observed at both portal and lobular zones. Furthermore, up-regulation of PPARα/γ protein levels was observed in liver tissue and it was associated with decreased levels of NF-κB also determined by western blot analysis. On the other hand, diet switch regimen resulted in a marked improvement in most parameters including: weight loss, increased insulin sensitivity, decreased steatosis, restored levels of insulin, glucagon, leptin, adiponectin and resistin. However, no significant changes were observed regarding inflammatory infiltrate in this last group.CONCLUSION 18-HEPE and 17-HDHA differentially exert hepatoprotective effects through up-regulation of nuclear receptors PPARα/γ and amelioration of serum adipokines profile.

尿素包合法联用分子蒸馏法富集鱼油中EPA和DHA的研究进展

鱼油中的EPA和DHA是一类具有很高营养价值的功能因子,对心脑血管健康、大脑发育、改善视力、抗炎等都有积极的作用,因而获取高纯度的EPA和DHA逐渐成为众多研究者关注的热点问题之一。采用尿素包合法富集鱼油中的EPA和DHA,不仅原料成本低廉,而且操作简单,但是富集得到的鱼油质量不高;而分子蒸馏法可以较好地保护EPA和DHA的活性,提高鱼油的纯度。两种方法联用具有工艺成熟、原料成本低、操作简单等优势,是工业化生产高质量EPA和DHA较好的选择之一。因此,在总结富集纯化鱼油中EPA和DHA方法的同时,阐述了尿素包合法、分子蒸馏法及两种方法联用富集鱼油中EPA和DHA的研究进展,希望可以为未来工业化获取高质量的EPA和DHA提供一定的参考价值。

二十碳五烯酸通过调节Nrf2通路抑制脂多糖诱导肾小球系膜细胞焦亡

目的:以核因子E2相关因子2(nuclear factor E2 related factor 2,Nrf2)蛋白为切入点,基于Nrf2/NLRP3/GSDMD信号通路探究二十碳五烯酸(eicosapentaenoic acid,EPA)对脂多糖(lipopolysaccharide,LPS)诱导肾小球系膜细胞焦亡的调控作用,结合Nrf2激动剂(4-OI)、核苷酸结合寡聚化结构域样受体蛋白3(nucleotide-bound oligomerized domain-like receptor protein 3,NLRP3)受体抑制剂(MCC950)探究EPA调控焦亡信号通路的机制。方法:LPS体外诱导肾小球系膜细胞(HBZY-1)焦亡模型,并根据不同药物处理分别设置空白对照组、LPS组、LPS+EPA组、LPS+EPA+4-OI组和LPS+EPA+MCC950组,其中LPS浓度为10μg/mL,EPA、4-OI和MCC950的浓度均为200μmol/L,按分组将药物同时加入培养板中处理48 h,利用CCK-8法、乳酸脱氢酶(LDH)释放实验、TUNEL染色检测细胞损伤,ELISA检测细胞上清液中炎症因子IL-1β、IL-18释放量,蛋白免疫印迹法检测Nrf2、NLRP3、Caspase-1、GSDMD蛋白表达水平。结果:LPS与EPA共处理HBZY-1细胞的细胞活力实验表明,10μg/mL LPS刺激48 h显著降低了细胞活力(P<0.05),但20~200μmol/L EPA对其有明显的保护作用(P<0.05)。采用200μmol/L EPA进行后续实验发现,EPA可明显保护LPS造成的细胞损伤(P<0.01),减少炎性因子(P<0.01)、LDH的释放(P<0.01)和DNA的断裂并抑制焦亡信号通路的激活,促进Nrf2蛋白的表达(P<0.01)。结合4-OI、MCC950共处理发现4-OI可以促进EPA对焦亡的抑制作用(P<0.05),减少相关蛋白的表达以及因子的释放(P<0.05),并增强EPA对细胞的保护(P<0.01),而MCC950对EPA发挥的作用无显著影响。结论:EPA通过Nrf2抑制LPS诱导的HBZY-1细胞焦亡信号通路各分子的表达,发挥细胞保护作用。

ω-3多不饱和脂肪酸健康机制及应用研究进展

ω-3多不饱和脂肪酸(omega-3 polyunsaturated fatty acids,ω-3 PUFAs)是一类重要的功能性高值脂肪酸,包括α-亚麻酸(ALA)、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)等,在膳食中主要来源于植物油或海洋多脂鱼类。近年来,利用微藻、丝状真菌、产油酵母等微生物生产ω-3 PUFAs,使其供应短缺、品质不稳定的问题显著改善,广泛扩大了其应用范围。ω-3 PUFAs在预防心血管疾病、神经退行性疾病、抑郁症、癌症,促进婴幼儿神经发育以及创面愈合和组织修复等方面均具有显著功效,其分子机制涉及缓解神经及系统性炎症、维持细胞结构及功能、激活机体免疫信号等。介绍了ω-3 PUFAs的结构及体内消化吸收过程,系统分析了DHA、EPA等发挥健康功效的分子机制及潜在的区别,总结了ω-3 PUFAs在食品中的应用形式,对ω-3 PUFAs应用的未来趋势进行了展望。提出了改进微生物发酵技术、构建高效基因编辑工具、开发活性保持技术等跨学科的研究方向,以期推动ω-3 PUFAs在食品和膳食补充剂领域的广泛应用。

轮枝霉(Diasporangiumsp.)产生EPA、AA发酵条件的初步研究

对本实验室分离的轮枝霉 (Diasporangiumsp )发酵产生含EPA、AA等多不饱和脂肪酸的条件 ,如碳源种类、氮源种类、pH、菌种的接种量和种龄、培养温度、通气量进行了研究 ,摇瓶发酵结果表明 ,以玉米粉和葡萄糖混合作为碳源能获得最高的不饱和脂肪酸产量 ;有机氮源有利于菌丝不饱和脂肪酸的产生 ;低温有利于菌丝中长链不饱和脂肪酸的产生 ,发酵接种量宜大 ;pH对菌丝生物量、EPA和AA的含量均有显著的影响。发酵培养 6d后菌丝中的不饱和脂肪酸含量达到最大值。在初步优化培养条件下 ,EPA、AA分别达到 2 5 3 7mg/L和 5 49 8mg/L。

提取及培养条件对紫球藻AA与EPA的影响

研究了紫球藻脂肪酸提取过程中不同的预处理方法(碾磨处理、超声波处理及未预处理)及提取分析方法(KOH-甲醇法、乙醚-石油醚法、氯仿-甲醇法、乙醇法、HCl-甲醇法)对紫球藻二十碳四烯酸与二十碳五烯酸的影响,结果表明,碾磨预处理是紫球藻不饱和脂肪酸二十碳四烯酸(AA)及二十碳五烯酸(EPA)检测效果最好且简便经济的方法,而氯仿-甲醇法对紫球藻AA及EPA的气相色谱(GC)分析效果最优,在同等条件下其灵敏度高,所取得的长链不饱和脂肪酸甲酯的产物多,EPA达到1.159mg/g,AA达到2.062mg/g;其他方法依次按效果排序为:乙醚-石油醚法>乙醇法>KOH-甲醇法>HCl-甲醇法。同时研究了不同培养时间对紫球藻AA与EPA组成的影响,结果表明,对数前期第6d为收获EPA的最佳时间,含量达到10.671mg/g;对数期末第8d为收获AA的最佳时期,含量达到19.415mg/g。