巴尔通体细胞脂肪酸成分分析

【目的】分析影响巴尔通体脂肪酸成分的主要因素,建立适合巴尔通体脂肪酸成分分析的标准化方法,探讨脂肪酸图谱应用于巴尔通体分类鉴定的可能性。【方法】应用气相色谱技术分析不同培养条件下巴尔通体脂肪酸的组成与含量的变化;应用已构建的标准化方法获取10株巴尔通体标准菌株和9株来自不同地区的汉赛巴尔通体猫分离株脂肪酸图谱;应用SPSS16.0统计软件对获得的数据资料进行聚类分析。【结果】培养基、温度和传代次数主要影响巴尔通体脂肪酸的微量成分;10株巴尔通体标准菌株的成分相似,但也存在构成和含量上的差异;在所测巴尔通体中,检出可分辨脂肪酸成分有20种,共有成分为7种,其中C18:1ω7c、C18:0和C16:0累积含量达80%以上;猫分离株被准确鉴定为汉赛巴尔通体。【结论】巴尔通体脂肪酸成分受培养基、温度等培养条件影响,在脂肪酸提取方法标化后,可用于汉赛巴尔通体种水平分类鉴定。     

冷冻干燥条件下酿酒酵母细胞脂肪酸组成变化的研究

以气相色谱法测定酿酒酵母(Saccharomyces cereuisiae) F159细胞膜类脂中脂肪酸的组成。结果表明,在低温干燥条件下,酿酒酵母细胞能自身调节脂肪酸的不饱和度,出现C_(16:1)脂肪酸含量增加,C_(16:0)脂肪酸含量略有所增,而C_(18:0)脂肪酸含量却有下降,不饱和直链脂肪酸之和与饱和直链脂肪酸之和的比值增加。说明这些变化使酿酒酵母细胞膜保持流动状态而维持细胞的稳定性和活性。初步探讨了冷冻干燥对酿酒酵母细胞脂肪酸组成的影响,为进一步探索和研究微生物抗冷冻干燥生理生化机制提供了依据。     

不同种类的脂肪酸对肝细胞脂质堆积的研究

目的：比较不同种类的脂肪酸对人肝癌细胞（HepG2）脂质堆积的影响。方法：HepG2细胞随机分为对照组（Con）、棕榈酸组（PA）、油酸组（OA）、亚油酸组（LA）和亚麻酸组（ALA）。培养24 h后,以MTT法比较不同种类脂肪酸对肝细胞存活率的影响;同一浓度下,以油红O染色法比较,各组细胞内脂滴生成情况拍照并测量吸光度;以酶学法检测各组细胞内甘油三酯含量比较不同种类脂肪酸对肝细胞脂质堆积的影响。结果：确定了每种脂肪酸诱导的浓度为50 μmol/L,同一浓度下,随着PA、OA、LA、ALA各组脂肪酸的不饱和度依次增加,PA、OA、LA、ALA各组细胞内脂滴依次增多,细胞内TG含量依次升高。与对照组相比,PA无统计学差异,OA存在显著性差异（P＜0.05）,而LA和ALA分别存在极显著性差异（P＜0.001）。且对每种脂肪酸诱导的肝细胞脂质堆积程度进行统计学分析,均存在显著性差异（P＜0.05）。结论：同一条件下,不同种类的脂肪酸对肝细胞活力和脂质堆积程度的影响不同,提示可能与脂肪酸的不饱和度有关,不饱和度越高的脂肪酸对细胞脂质堆积作用越明显。     

Cryptococcus curvatus O3酵母菌培养及产油脂特性

生物柴油的发展, 导致全球油脂供求紧张。微生物油脂的甘三酯组成与植物油类似, 发展微生物油脂可部分缓解植物油脂供应压力。本文研究了Cryptococcus curvatus O3酵母利用葡萄糖为碳源生长和积累油脂的特性。Cryptococcus curvatus O3酵母在培养过程中能适应间歇式碳源流加方式达到高密度培养的目的, 但在相同培养条件下, 不同氮源能影响其代谢过程中糖到油脂转化的脂肪系数。Cryptococcus curvatus O3酵母利用葡萄糖作为碳源在30°C下摇瓶发酵, 菌体生物量为51.8 g/L, 油脂含量达65.1%。脂肪酸组成分析结果表明, 菌油富含饱和及低度不饱和长链脂肪酸, 其中饱和脂肪酸之和占总脂肪酸组成的64%左右, 其脂肪酸组成类似于可可脂, 这些结果对于利用产油微生物转化生物质获取如类可可脂等具有高附加值油脂的研究具有重要意义。     

极端干旱区防护林地土壤微生物多样性

土壤微生物在森林土壤中有重要功能.采用传统培养、脂肪酸鉴定和PCR-DGGE 3种方法分别研究了塔里木沙漠公路防护林地土壤微生物数量、脂肪酸种类和细菌DNA片段的多样性,从微生物学角度为塔里木沙漠公路防护林的管理提供理论依据.结果表明,塔里木沙漠公路防护林的建设促进了风沙土土壤微生物的发育,随着防护林定植年限的增加,土壤微生物数量、脂肪酸和细菌DNA片段的多样性指数明显增大;土壤微生物区系组成中,细菌是优势类群,占微生物总数80%以上,而真菌很少,不到微生物总数1%,但在不同土层间有所差异;传统培养法与现代生物标记和分子生物学方法对塔里木沙漠公路防护林地土壤微生物多样性的研究结果基本一致,说明塔里木沙漠公路防护林的建设使林地土壤生物活性有所增强,有利于林地土壤养分循环与利用.     

若尔盖高寒湿地干湿土壤条件下微生物群落结构特征

土壤水分含量的空间异质性是引起湿地生态系统结构和功能空间变异的关键因素。目前有关低纬度高寒湿地土壤水分对微生物群落结构影响的研究较少。于2007年4月(冷季)和8月(暖季)采集若尔盖高寒湿地常年淹水和无淹水两种水分条件的土壤样品,利用磷脂脂肪酸方法分析其微生物群落结构。结果表明,土壤微生物总生物量、细菌生物量、革兰氏阳性细菌及革兰氏阴性细菌生物量均表现为常年淹水土壤高于无淹水土壤,且4月份高于8月份;与土壤通气量关系密切的真菌、放线菌,其生物量表现为无淹水土壤显著高于常年淹水土壤;反映群落组成的真菌:细菌磷脂脂肪酸比值也表现为无淹水土壤显著高于常年淹水土壤。磷脂脂肪酸的主成分分析表明,水分条件不同的两种土壤中微生物群落结构显著不同,季节变化并未引起土壤微生物群落结构的改变。     

脂肪酸标准物质的研究进展

脂肪酸是一类具有重要功能的生物分子,广泛存在于动植物体内,是人体的重要组成成分,与人体很多疾病的发生都息息相关。脂肪酸标准物质是脂肪酸检测结果准确与否的依据,世界各国都在积极研制,目前我国脂肪酸标准物质研制单位主要有国家粮食局科学研究院和中国计量科学研究院等。综述了国内外脂肪酸标准物质的现状,对比分析了国内外脂肪酸标准物质的种类、特性量值组成和定值方法等。国外脂肪酸标准物质一般含有多种特性组分,特性量值较多,国内脂肪酸标准物质一般仅针对脂肪酸测量研制,基体比较单一,特性组分较少,量值较少。     

脂肪酸合成系统潜能的挖掘与释放

在全球石油资源不断减少和温室气体不断积累的情况下,急需发展可再生燃料能源及各种生物化工原料和产品。基于该目的,能够生产高能量密度液体生物燃料和高附加值化工品的微生物脂肪酸合成系统备受关注。首先介绍了大肠杆菌脂肪酸代谢系统的组成,然后详细总结了通过改造脂肪酸代谢途径生产脂肪酸以及脂肪酸衍生物的最新研究进展,并介绍了利用体外重建体系来研究脂肪酸合成途径对该系统进行深入挖掘,以及根据得到的信息指导体内脂肪酸途径的改造来释放脂肪酸合成系统的潜能。     

磷脂脂肪酸谱图分析方法及其在微生物生态学领域的应用

应用磷脂脂肪酸谱图分析技术对微生物群落进行定量分布,克服了传统的微生物培养方法和显微技术的局限性。介绍了磷脂脂肪酸谱图分析方法及其在微生物生态学领域中的应用,包括对微生物群落的生物量、群落结构、营养状况和新陈代谢活动等方面的研究。     

高脂饮食诱导肠道微生物代谢产物短链脂肪酸改变进而影响食物过敏的发生

通过回顾过敏性疾病以及高脂饮食、肥胖等的大量研究报告,探究高脂饮食以及高脂饮食带来的肥胖是否会对食物过敏的发生产生影响以及可能的机制。研究发现,高脂饮食可能会增加食物过敏发生率,降低食物过敏阈值,增加食物过敏的风险,并且高脂饮食对肠道微生物的影响是其中的一个原因。高脂饮食改变肠道微生物结构,导致短链脂肪酸产生差异,而短链脂肪酸通过G蛋白偶联受体、组蛋白乙酰化等途径引起Treg细胞分化、IgA产生以及致耐受性的DC细胞产生,影响肠道屏障的健康,因此,高脂饮食对肠道微生物结构的改变带来的短链脂肪酸的产生差异影响了肠道屏障的健康,进而导致食物过敏的阈值降低,易感性增加。     

Biochemistry of radioiodinated free fatty acids

Summary Radioiodinated free fatty acids have been developed to study myocardial metabolism non-invasively in man. In the present study the distribution of radiolabeled lipids in the myocardium and in arterial and coronary sinus blood was evaluated following injection of three commonly used iodinated fatty acids in fasted (n = 5) and lactate loaded (n = 3) dogs. Five minutes after simultaneous i.v. injection of radioiodinated 17-I-heptadecanoic acid (IHDA),15-(p-I-phenyl) pentadecanoic acid (IPPA) and 15-(p-I-phenyl)-3,3-dimethylpentadecanoic acid (DMIPPA) a biopsy specimen and samples of arterial and coronary sinus blood were taken. After extraction and TLC the relative distribution of radioactivity in the aqueous phase (containing the oxidation products), pellet and organic phase was calculated. The organic phase was further divided into phospholipids, diglycerides, free fatty acids, triglycerides and cholesterolesters. Seventy two percent of IHDA was oxidized, 36% of IPPA and 7% of DMIPPA. The organic phase consisted primarily of triglycerides and phospholipids. The ratios of triglycerides to phospholipids were about the same for IHDA, IPPA and DMIPPA (0.58, 0.65 and 0.50, respectively). Free IHDA in tissue samples was low (4%) and elevated for IPPA and DMIPPA, (17% and 37%). During lactate loading triglycerides were higher for all three fatty acids. For IHDA and IPPA this increase was paralleled by a decrease in the aqueous phase, in case of DMIPPA the aqueous phase remained the same. Five minutes after injection most of the organic phase of both arterial and coronary sinus blood consisted of the injected fatty acids, the aqueous phase contained oxidation products. There were only minor differences during lactate loading. During the evaluation of scintigraphic patterns of the radioiodinated fatty acids under normal conditions (eg at rest) and during elevated lactate levels (eg during exercise) the differences in distribution must therefore be considered.     

培养条件对头孢霉脂肪酸链长和ω-3脱饱和的影响*

为了获得高产量的长链ω-3多不饱和脂肪酸,用十八碳脂肪酸和十六碳脂肪酸的比值考察碳链延长,用α-亚麻酸和亚油酸的比值考察ω-3脱饱和;探讨了八种因子对脂肪酸链长和ω-3脱饱和的影响。有利于碳链延长的条件为：麦芽糖10g/L、(NH4)2SO4 3g/L、起始pH为4.0、500mL三角瓶装50mL培养基、接种20%（V/V）、20℃培养6d。有利于ω-3脂肪酸生成的条件为：蔗糖30g/L、NH4Cl 3g/L、培养基起始pH为4.0、500mL三角瓶装50mL培养基、接种20%（V/V）、10℃培养10d。     

Subject index

Heats of fusion and heat capacities have been measured for saturated, unsaturated and hydroxy fatty acids, differing in degree of unsaturation, geometric isomerism, and position of unsaturated and hydroxy groups. Entropies of fusion are used to draw conclusions concerning molecular structure of fatty acid chains and lateral chain-chain interactions. Position of the functional group on the chain does not seem to significantly affect the entropy values for trans and cis single double bonds and single triple bonds, but differences are noted with hydroxy group position. Whereas single acid triglycerides of saturated acids have entropies which are about three times that of the corresponding acid, cis and trans single acid triglycerides do not show the same relationship with their corresponding acids. Comparing entropies of fusion for certain groups of fatty acids, only differing in carbon number, allows the estimation of chain equivalence with saturated fatty acids. Hence, for example it is shown that a 22 to 23-carbon cis mono-unsaturated fatty acid is equivalent to an 18-carbon saturated fatty acid.     

细菌脂肪酸合成多样性的研究进展

与哺乳动物、真菌采用I型脂肪酸合成系统不同,细菌采用II型脂肪酸合成系统,每步反应都由独立的酶催化,因此细菌脂肪酸合成酶是研究抗菌药物的优良靶标。研究表明,在不同细菌中参与脂肪酸合成的酶都具有较高的多样性,而脂肪酸种类不同,合成方式也不尽相同,本文对此进行了总结。     

Fats for thoughts: An update on brain fatty acid metabolism

Brain fatty acid (FA) metabolism deserves a close attention not only for its energetic aspects but also because FAs and their metabolites/derivatives are able to influence many neural functions, contributing to brain pathologies or representing potential targets for pharmacological and/or nutritional interventions.Glucose is the preferred energy substrate for the brain, whereas the role of FAs is more marginal. In conditions of decreased glucose supply, ketone bodies, mainly formed by FA oxidation, are the alternative main energy source. Ketogenic diets or medium-chain fatty acid supplementations were shown to produce therapeutic effects in several brain pathologies.Moreover, the positive effects exerted on brain functions by short-chain FAs and the consideration that they can be produced by intestinal flora metabolism contributed to the better understanding of the link between “gut-health” and “brain-health”.Finally, attention was paid also to the regulatory role of essential polyunsaturated FAs and their derivatives on brain homeostasis.     

Dietary macronutrients modulate the fatty acyl composition of rat liver mitochondrial cardiolipins

The interaction of dietary fats and carbohydrates on liver mitochondria were examined in male FBNF1 rats fed 20 different low-fat isocaloric diets. Animal growth rates and mitochondrial respiratory parameters were essentially unaffected, but mass spectrometry-based mitochondrial lipidomics profiling revealed increased levels of cardiolipins (CLs), a family of phospholipids essential for mitochondrial structure and function, in rats fed saturated or trans fat-based diets with a high glycemic index. These mitochondria showed elevated monolysocardiolipins (a CL precursor/product of CL degradation), elevated ratio of trans-phosphocholine (PC) (18:1/18:1) to cis-PC (18:1/18:1) (a marker of thiyl radical stress), and decreased ubiquinone Q₉; the latter two of which imply a low-grade mitochondrial redox abnormality. Extended analysis demonstrated: i) dietary fats and, to a lesser extent, carbohydrates induce changes in the relative abundance of specific CL species; ii) fatty acid (FA) incorporation into mature CLs undergoes both positive (>400-fold) and negative (2.5-fold) regulation; and iii) dietary lipid abundance and incorporation of FAs into both the CL pool and specific mature tetra-acyl CLs are inversely related, suggesting previously unobserved compensatory regulation. This study reveals previously unobserved complexity/regulation of the central lipid in mitochondrial metabolism.     

Synthesis of 3-O-acyl esters of serine and threonine

The 3-O-acyl derivatives of serine and threonine have been prepared by reacting oleoyl chloride and palmitoyl chloride with N-t-butoxycarbonyl (N-T-BOC) serine and N-t-BOC threonine. The t-BOC group was removed by treatment with 4 N HCl in dioxane. The products were identified by proton magnetic resonance spectroscopy, infrared spectroscopy, elemental analysis and chromatographic properties. The O-acyl serines and O-acyl threonines were converted to their methyl esters by treatment with boron trifluoride in methanol and were converted to their dinitrophyl derivatives by treatment with dinitrofluorobenzen (DNFB). The yield of the dinitrophenyl derivatives was very high but the yield of methyl esters was low due mainly to methanolysis and loss of the fatty acyl group. The O-acyl serines and O-acyld threonines prepared will provide standards for researchers who are interested in identifying fatty acids esterified to serine and threonine hydroxyl groups in membrane proteins.