共轭亚油酸生理功能及微生物合成调控研究进展

共轭亚油酸(conjugated linoleic acid,CLA)是一种新型功能性油脂,顺9,反11-十八碳二烯酸(c9,t11-CLA)和反10,顺12-十八碳二烯酸(t10,c12-CLA)由于具有比其他异构体更强的生理功能得到广泛关注和研究.微生物合成CLA具有安全性高、选择特异性强等特点,研究CLA产量提高...     

功能性脂质——共轭亚油酸的功能及应用研究进展

共轭亚油酸(conjugated linoleic acid,CLA)是一种具有抗动脉粥样硬化、抗癌、免疫调节、降糖、促进骨细胞及骨骼形成等众多功能特性的新资源食品。本文中,笔者对CLA的来源、合成方法、功能及应用的研究进展进行综述,以期为相关的研究者提供参考。     

共轭亚油酸对脂肪代谢相关基因表达的影响

本文利用实时定量PCR的测定方法,分析了两种共轭亚油酸(CLA)异构体对3T3-L1小鼠前脂肪细胞脂肪代谢相关基因表达的影响。本研究CLA异构体的处理浓度和时间为75.4μmol/L,8 d,测定了与能量代谢、细胞凋亡、脂肪酸氧化作用和脂解作用相关的多种基因的mRNA水平。结果显示:两种异构体均能够显著提高UCP1、UCP3、Perilipin和PPARα的mRNA水平,而抑制UCP2的表达水平(P<0.01)。与cis-9t,rans-11CLA相比t,rans-10c,is-12 CLA显著提高PKA(P<0.05)、CPT-1和TNF-α(P<0.01)的mRNA水平。与对照组相比,两种CLA异构体处理组均对HSL、ATGL、ACO和Leptin的基因表达无显著影响。     

视黄酸X受体α促进猪前体脂肪细胞分化

采用细胞转染、油红O染色、油红O染色提取法、GPDH活性测定、semi-qRT-PCR等方法研究了视黄酸X受体α (retinoic acid X receptor α, RXRα)在猪原代前体脂肪细胞分化中的作用及其机理.结果表明,转染pRXRα-EGFP促进了猪前体脂肪细胞RXRα 的表达,脂肪细胞分化能力随之增强, 脂肪细胞GPDH活性、分化转录因子PPARγ和C/EBPαmRNA表达水平均显著升高(P<0.05). 结果提示,RXRα可能通过调控过氧化物酶体增殖物激活受体γ(peroxisome proliferators-activated receptor-γ, PPARγ)和CAAT/增强子结合蛋白家族（CCAAT/enhancer binding proteins, C/EBP）C/EBPα 基因表达变化促进猪前体脂肪细胞分化.     

侧脑室注射共轭亚油酸(CLA)对大鼠糖脂代谢的影响

观察侧脑室注射共轭亚油酸(Conjugated linoleic acid,CLA)对SD大鼠糖脂代谢的影响及其可能的机制。方法:向正常SD大鼠侧脑室内注射共轭亚油酸(CLA),分别于注射后2、4、8、12、24小时采血,试剂盒法测血糖、胰岛素、瘦素、血甘油三脂、血胆固醇、血高密度脂蛋白。48小时后处死,分离动物的脂肪(皮下、内脏、肾周、睾周)进行称重,计算体脂比。结果:与对照组相比,侧脑室注射CLA48小时后,大鼠脂体比、皮下脂肪、睾周脂肪均下降。术后2-12h血糖降低,血清胰岛素浓度也降低,而且持续的时间较长(48h)。侧脑室注射CLA对脂代谢有影响,2h时血清甘油三酯升高、胆固醇降低、4h时高密度脂蛋白升高。结论:共轭亚油酸能够通过中枢神经系统调节外周糖脂代谢,这可能与其能减轻体重的机制有关。     

一株产共轭亚油酸乳酸菌的鉴定及其特性

从酸菜汁中分离筛选到一株产共轭亚油酸(CLA)能力较高的乳酸菌。经鉴定,确定为植物乳杆菌Lactobacliius plantarum。微氧条件可提高CLA的产量,催化亚油酸(LA)生成CLA的酶受着LA的诱导。37℃对细胞生长和CLA生成最为有利。对数生长期为6～12h,18h后进入稳定期。在14～22h,CLA生成量快速增加,24h时达到最高值。该菌的培养物经萃取、甲酯化后,进行了气相色谱分离,生成的CLA产物为c9/t9,c11-CLA和t10,c12-CLA异构体的混合物。     

视黄酸相关孤儿核受体RORα在脂质代谢调控中的作用

核受体是一类配体依赖的转录因子超家族。视黄酸相关孤儿核受体(retinoid-related orphan nuclear receptors,RORs)由于在基因序列上与视黄酸受体(retinoic acid receptor,RAR)和类维甲酸X受体(retinoid X receptor,RXR)相似而得名。近年来研究陆续发现,核受体RORα不仅在一些代谢组织中表达,而且在脂质代谢,以及动脉粥样硬化的发生发展中扮演关键角色。因此,深入了解RORα与脂质代谢的关系,将为肥胖、2型糖尿病和动脉粥样硬化等疾病提供新的治疗靶点。     

共轭亚油酸单体诱导乳腺癌细胞SKBr3凋亡的PPARγ信号通路研究

cis9,trans11-CLA和trans10,cis12-CLA是共轭亚油酸(CLA)二种抑瘤活性最强的主要单体．在以前报道二者诱导乳腺癌细胞凋亡的工作基础上,进一步探讨共轭亚油酸单体诱导乳腺癌细胞SKBr3凋亡的途径及机制．采用RT-PCR和　　Western blot等方法,证实了CLA在SKBr3细胞中可显著提高PPARγ 的转录及蛋白质表达水平,并发现CLA对PPARγ与凋亡相关蛋白Bax、Bcl-2和caspase3的表达影响呈同步相关性,并表现出时间和剂量依赖性．通过PPARγ 抑制剂GW9662实验表明它们之间存在协同关系．首次提出了PPARγ -Bcl-2-Caspase3信号通路的SKBr3细胞凋亡途径,为CLA有望作为PPARγ新型调节剂诱导肿瘤细胞凋亡在临床应用提供实验证据．     

畜禽PPARα基因研究进展

过氧化物酶体增殖物激活受体(Peroxisome proliferator-activated receptors,PPARs)是核激素受体家族中的配体激活受体,控制许多细胞内的代谢过程,PPARα作为过氧化物酶体增殖物激活受体家族重要成员之一,是调控机体脂质代谢的重要枢纽,在调控畜禽机体肝脏脂质代谢方面有重要作用。PPARα基因由四个结构域组成,多在机体肝脏和脂肪组织中表达,可作为细胞核受体被外源和内源的特异性配体结合并激活,进而结合靶基因发挥对肝脏脂质代谢的调控作用。就PPARα基因的结构特点及表达模式、PPARα基因对肝脏脂代谢的调控机制,以及现阶段PPARα在畜禽方面的研究进展进行阐述,旨在引起人们对PPARα基因调控脂质代谢的关注,并为畜禽肝脏脂质代谢过程的机理研究和相关疾病的治疗提供一些理论支持。     

共轭亚油酸对HepG2细胞脂质沉积的影响

目的:研究共轭亚油酸(conjugated linoleic acid,CLA)对HepG2细胞脂肪沉积的影响,以探讨其对肝脏脂肪沉积的可能机制.方法:体外培养HepG2细胞,不同浓度CLA(0、10、50、100 μmol.1-1)作用24小时后,100 nmol.1-1胰岛素作用1小时.以比色法测定培养液中游离脂肪酸的含量,油红O染色观察细胞脂肪沉积,Western-blot检测Akt和P-Akt蛋白表达.结果:随着CLA浓度增加,培养液中的游离脂肪酸含量显著降低,细胞中红染脂滴增多,Western-blot结果发现,Akt蛋白的磷酸化水平增高.结论:CLA可以增加细胞内脂肪合成和细胞中Akt蛋白的磷酸化水平.     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

Chemokines and cytokines: axis and allies in asthma and allergy

Allergic asthma can be precipitated by many factors. For the atopic person, fungus, pollen, dust mites, cockroach antigens, and diesel exhaust are all agents that may trigger an allergic attack. Cytokines and chemokines are integral mediators of fungal asthma. From the earliest time points, they recruit and activate the cells required for the clearance of fungus as well as being critical factors involved in the immunopathology of this disease. In the final analysis, it is clear that these mediators can act to the benefit or the detriment of the host.     

人血管能抑素基因的克隆、表达及其表达产物的纯化和生物活性测定

以人胎盘脐带组织为材料,提取组织总RNA,用netRTPCR方法合成人血管能抑素cDNA基因,将该cDNA克隆进pSP72载体获得重组质粒pSP72C, DNA序列分析结果与预期序列一致。用BamHⅠ和NdeⅠ双酶切,切下pSP72C上的血管能抑素cDNA,插入pET3c载体的相应位点获得重组表达质粒pETC, 转化E. coli BL21(DE3), SDSPAGE分析显示：在IPTG诱导下,血管能抑素基因获得了高效表达,表达量约占菌体总蛋白的 27.9 %,主要以包涵体形式存在。包涵体经过洗涤、裂解、蛋白复性以及Sephadex G75凝胶过滤层析等步骤后,获得了纯度达91.4 %的人血管能抑素。CAM实验证明10 μg纯化蛋白就能显著抑制鸡胚新生血管生成。     

Oxidation and nitration of ribonuclease and lysozyme by peroxynitrite and myeloperoxidase

In spite of the many studies on protein modifications by reactive species, knowledge about the products resulting from the oxidation of protein-aromatic residues, including protein-derived radicals and their stable products, remains limited. Here, we compared the oxidative modifications promoted by peroxynitrite and myeloperoxidase/hydrogen peroxide/nitrite in two model proteins, ribonuclease (6Tyr) and lysozyme (3Tyr/6Trp). The formation of protein-derived radicals and products was higher at pH 5.4 and 7.4 for myeloperoxidase and peroxynitrite, respectively. The main product was 3-nitro-Tyr for both proteins and oxidants. Lysozyme rendered similar yields of nitro-Trp, particularly when oxidized by peroxynitrite. Hydroxylated and dimerized products of Trp and Tyr were also produced, but in lower yields. Localization of the main modified residues indicates that peroxynitrite decomposes to radicals within the proteins behaving less specifically than myeloperoxidase. Nitrogen dioxide is emphasized as an important protein modifier.