食用菌提取物对胰岛素抵抗细胞体外糖代谢的影响

以高胰岛素诱导的HepG2细胞和地塞米松诱导的3T3-L1脂肪细胞两种胰岛素抵抗细胞模型,分别对9种食用菌(桑黄、灵芝、香菇、杏鲍菇、鸡腿菇、灰树花、猴头、姬松茸和蛹虫草)醇提物、桑黄和灵芝的4种有机溶剂(正丁醇、乙酸乙酯、氯仿和石油醚)萃取物的体外降糖活性进行了研究。HepG2模型研究结果表明,9种食用菌醇提物中灵芝和桑黄醇提物促进细胞葡萄糖消耗效果最好,并且两者高浓度组的葡萄糖消耗量均好于阳性对照组;桑黄3种有机溶剂萃取相(正丁醇相、乙酸乙酯相和石油醚相)和灵芝4种有机溶剂萃取相促进细胞葡萄糖消耗效果较好,均好于阳性对照组。3T3-L1细胞模型结果表明,9种食用菌醇提物中灵芝和桑黄醇提物的促进葡萄糖消耗效果最好,均好于阳性对照组;灵芝及桑黄4种有机溶剂萃取相中,乙酸乙酯萃取相的葡萄糖消耗效果较好。     

胰岛素诱导3T3-L1脂肪细胞胰岛素抵抗模型的建立

为建立胰岛素抵抗脂肪细胞模型,以3T3-L1前脂肪细胞为研究材料,通过3-异丁基-1-甲基黄嘌呤、地塞米松和胰岛素联合诱导其分化为3T3-L1脂肪细胞,通过葡萄糖消耗实验研究胰岛素诱导3T3-L1脂肪细胞产生胰岛素抵抗的作用浓度和时间关系,发现10-7mmol/L胰岛素诱导处理48h是3T3-L1脂肪细胞产生胰岛素抵抗的最适条件,该细胞模型的胰岛素抵抗状态可维持48h。通过高浓度胰岛素成功诱导3T3-L1脂肪细胞产生胰岛素抵抗,具有建模周期短、重复性好、操作简便的优点,该细胞模型可以用于抗胰岛素抵抗天然产物的筛选研究。     

白藜芦醇对胰岛素抵抗3T3-L1脂肪细胞葡萄糖代谢的影响

目的：研究白藜芦醇(resveratrol,Res)对胰岛素抵抗状态下3T3-L1 脂肪细胞葡萄糖代谢的影响,并探讨其分子机制。方法：用地塞米松诱导3T3-L1 细胞建立胰岛素抵抗模型,用不同剂量Res 进行干预,添加或不添加胰岛素刺激,测定各组细胞的葡萄糖消耗量,实时荧光定量PCR 检测各组细胞的脂联素(adiponectin)、瘦素(leptin)和抵抗素(resistin)mRNA 表达,Western blotting 检测腺苷酸激活蛋白激酶(AMP-activated protein kinase,AMPK)的蛋白质表达及磷酸化水平。结果：各组细胞经胰岛素刺激,0.01、0.1、1μmol/L 的Res 组的葡萄糖消耗量分别是对照组的1.3、1.5、1.4 倍(P ＜ 0.05),添加Res 可促进脂联素、瘦素mRNA 的表达,降低抵抗素mRNA表达,增加AMPKα的磷酸化水平。结论：Res 可以明显改善胰岛素抵抗状态下3T3-L1 细胞葡萄糖代谢。其机制可能是通过增加脂联素、瘦素表达,降低抵抗素表达从而介导AMPKα磷酸化实现的。     

人参皂苷F2通过PI3K/Akt途径改善3T3-L1脂肪细胞胰岛素抵抗

该研究探讨了人参皂苷F2对3T3-L1脂肪细胞胰岛素抵抗的影响及其机制。将3T3-L1前脂肪细胞诱导分化成熟后,用1 μmol/L地塞米松处理48 h,建立胰岛素抵抗模型。用10 μmol/L的罗格列酮（阳性对照）和25、50、100 μmol/L人参皂苷F2处理胰岛素抵抗细胞12 h,检测细胞对2-NBDG的摄取。实验结束后用RT-qPCR检测各组细胞中葡萄糖转运蛋白4（GLUT-4）和胰岛素底物受体1（IRS-1）mRNA相对表达量,并利用Western blot检测PI3K/Akt信号通路中蛋白表达及其磷酸化水平。结果表明：与模型组相比,25、50、100 μmol/L人参皂苷F2均能促进胰岛素抵抗3T3-L1脂肪细胞对2-NBDG的摄取,分别增加了12.58%、29.07%和34.62%（p<0.05）;人参皂苷F2作用12 h后,GLUT-4和IRS-1 mRNA相对表达量以及PI3K、Akt的磷酸化水平显著提高（p<0.01）。该研究表明人参皂苷F2可通过促进胰岛素抵抗3T3-L1脂肪细胞中GLUT-4和IRS-1mRNA相对表达,增加PI3K和Akt蛋白磷酸化,从而激活PI3K/Akt信号通路,改善其糖代谢和胰岛素抵抗。     

苦瓜水提物和醇提物对HepG2细胞胰岛素抵抗的调节作用

为研究苦瓜水提物(BMWE)和醇提物(BMEE)调节胰岛素抵抗的异同点,本文采用棕榈酸诱导HepG2细胞建立胰岛素抵抗(IR)细胞模型,测定了BMWE和BMEE对HepG2-IR细胞葡萄糖消耗量、糖原、甘油三酯(TG)、ATP及胰岛素抵抗信号通路相关基因mRNA表达水平的影响。结果表明,BMWE和BMEE均可显著增加IR细胞的葡萄糖消耗量和胞内糖原含量;BMEE还能显著降低细胞中TG含量(112.08%vs.132.97%)、增加细胞中ATP含量(80.62%vs.48.44%);同时BMWE和BMEE均能显著提高IR细胞中IRS1(胰岛素受体1)、PI3K(磷脂酰肌醇-3-激酶)、AMPK(腺苷酸活化蛋白激酶)和CPT1(肉毒碱棕榈酰转移酶1)mRNA的表达水平,降低ACC2(乙酰辅酶A羟化酶2)mRNA的表达水平;BMWE还可增加细胞中AKT(蛋白激酶B)mRNA的表达水平。在mRNA水平,BMWE通过激活IR细胞的IRS1-PI3K-AKT信号通路改善胰岛素抵抗;而BMEE则通过调节AMPK-ACC2-CPT1信号通路改善IR细胞的糖脂代谢,二者的作用途径有所不同。     

小麦烷基间苯二酚对3T3-L1脂肪细胞胰岛素抵抗改善作用及机制

低度慢性炎症状态是肥胖导致机体胰岛素抵抗的重要原因之一.小麦烷基间苯二酚(alkylresorcinols,ARs)是全麦食品膳食的生物标记物和重要的活性功能成分.利用体外炎症因子诱导,建立3 T3-L1成熟脂肪细胞胰岛素抵抗模型,通过检测脂肪细胞脂质分解和葡萄糖吸收与利用情况,探讨小麦ARs在炎症状态下对脂肪细胞胰岛素抵抗的保护机制.研究结果表明:不同浓度小麦ARs(5～20μmol/L)干预能够剂量依赖性地改善炎症因子诱导的3T3-L1脂肪细胞胰岛素抵抗,脂肪细胞对葡萄糖利用率分别提升了4.3％、10.2％ 和24.0％;小麦ARs可以显著缓解炎症因子导致的脂肪细胞脂质分解.进一步机制解析发现:炎症因子显著降低了脂肪细胞糖代谢两个关键蛋白Akt的磷酸化(p-Akt)及其下游GLUT4蛋白表达,导致其葡萄糖利用障碍,而ARs干预显著提升了这两个蛋白的表达;采用PI3K抑制剂(LY294002)预处理脂肪细胞后,ARs对于脂肪细胞p-Akt及GLUT4表达的增加被抑制,相应的对于葡萄糖吸收的改善作用也被显著降低,脂肪细胞脂质分解增加,表明ARs通过特异性激活p-Akt/GLUT4信号通路改善了3 T3-L1脂肪细胞胰岛素抵抗.最后,研究了小麦ARs的5种主要单体成分分别对于脂肪细胞胰岛素抵抗的改善作用,结果表明,十七烷基间苯二酚是小麦ARs发挥生理功能的主要活性物质.     

苦瓜碱提多糖调节HepG2细胞胰岛素抵抗的途径

为研究苦瓜碱提多糖(AEMP)调节胰岛素抵抗的作用途径,采用0.25 mmol/L棕榈酸诱导HepG2细胞建立胰岛素抵抗细胞模型,并测定AEMP和二甲双胍对胰岛素抵抗细胞葡萄糖消耗量、糖原、甘油三酯(TG)及胰岛素抵抗信号通路相关基因m RNA表达水平的影响。结果表明,250,500,750μg/m L AEMP均可显著增加胰岛素抵抗细胞的葡萄糖消耗量(从78.58%分别增至93.31%、94.57%和97.07%);750μg/m L AEMP能显著增加糖原含量(从70.78%增至95.51%),降低TG含量(从132.97%降至115.93%);AEMP还可显著提高胰岛素抵抗细胞中PI3K(磷脂酰肌醇-3-激酶)、AKT(蛋白激酶B)和PGC-1α(过氧化物酶体增殖活化受体γ共激活因子-1α)m RNA的表达水平,降低PEPCK(磷酸烯醇式丙酮酸羧激酶)m RNA的表达水平。AEMP主要通过激活胰岛素抵抗细胞的PI3K-AKT和PGC-1α信号通路改善胰岛素抵抗;而二甲双胍则主要通过激活AMPK-ACC2(腺苷酸活化蛋白激酶-乙酰辅酶A羟化酶2)和PGC-1α信号通路,调节胰岛素抵抗细胞的糖脂代谢,二者的作用途径有所不同。     

猫豆乙醇提取物对3T3-L1脂肪细胞糖脂代谢的影响

探讨猫豆乙醇提取物(MPEE)对胰岛素抵抗3T3-L1脂肪细胞糖脂代谢的影响。用含高浓度葡萄糖和高浓度胰岛素的DMEM培养基制备胰岛素抵抗3T3-L1脂肪细胞模型。模型细胞经不同浓度MPEE处理24 h后检测培养液中的葡萄糖消耗量、游离脂肪酸(FFA)、甘油、三酯甘油(TG)及肿瘤坏死因子(TNF-α)和白介素6(IL-6)水平。实时定量PCR(q RT-PCR)检测细胞中葡萄糖转运蛋白(GLUT-4)、激素敏感脂肪酶(HSL)和炎性介质[TNF-α、IL-6、单核细胞趋化蛋白-1(MCP-1)、C反应蛋白(CRP)]的m RNA表达。MPEE可促胰岛素抵抗模型细胞对葡萄糖的消耗,降低细胞中TG含量,减少FFA和甘油溢出。同时,MPEE还能抑制模型细胞TNF-α和IL-6分泌,及炎性介质(TNF-α、IL-6、MCP-1、CRP)的m RNA表达。此外,MPEE能上调细胞中GLUT-4的表达,并降低HSL的m RNA表达。结果显示,MPEE可有效刺激3T3-L1脂肪细胞消耗葡萄糖,促TG分解,减少FFA和甘油的溢出。调控细胞糖、脂代谢来改善胰岛素抵抗,并降低胰岛素抵抗发生时的炎症水平。     

发酵糙米乙醇提取物改善3T3-L1脂肪细胞糖脂代谢

探讨发酵糙米乙醇提取物(FBREE)对胰岛素抵抗3T3-L1脂肪细胞糖脂代谢的影响。高浓度葡萄糖加胰岛素刺激诱导3T3-L1脂肪细胞胰岛素抵抗模型。不同浓度FBREE处理细胞24 h后检测培养液中葡萄糖,游离脂肪酸(FFA),甘油,甘油三酯(TG),肿瘤坏死因子(TNF-α)和白介素6(IL-6)水平。实时定量PCR检测细胞氧化物酶体增殖激活受体γ(PPARγ),CAATT增强子结合蛋白(C/EBPα),固醇调节元件结合蛋白(SREBP1c),葡萄糖转运蛋白4(GLUT4),脂肪酸结合蛋白(a P2),蛋白酪氨酸磷酸酶1B(PTP1B),葡萄糖转运蛋白(GLUT-4),激素敏感脂肪酶(HSL)和TNF-α,IL-6,单核细胞趋化蛋白-1(MCP-1)和C反应蛋白(CRP)的m RNA表达。FBREE具有促进细胞葡萄糖利用,降低细胞内TG含量,减少FFA及甘油溢出的能力。与模型组细胞相比,高浓度FBREE(100μg/m L)处理的细胞中TG和FFA水平分别下降52.44%和37.83%。FBREE同时能减少模型细胞TNF-α和IL-6的分泌,高浓度FBREE(100μg/m L)分别抑制TNF-α(21.18%),IL-6(31.39%),MCP-1(40.09%)和CRP(41.73%) mRNA表达。此外,FBREE有效降低细胞中PPARγ,C/EBPα,SREBP1c,PTP1B,a P2和HSL的m RNA表达,上调GLUT-4m RNA表达。结果提示,FBREE能有效促3T3-L1脂肪细胞消耗葡萄糖,分解TG,减少FFA和甘油溢出;调控细胞糖、脂代谢来改善胰岛素抵抗,并降低胰岛素抵抗所致炎症水平的升高。     

D-手性肌醇及D-松醇对缓解HepG2细胞胰岛素抵抗的作用

对D-手性肌醇及D-松醇缓解胰岛素抵抗作用进行评价,选用HepG2人肝癌细胞建立胰岛素抵抗细胞模型。将实验分为正常对照组和D-手性肌醇及D-松醇实验组,分别设立50、100、200、400mg/L4个剂量。采用四甲基偶氮唑盐法(MTT法)检测受试样品对细胞增殖的影响。选用1×10-6mol/L浓度的胰岛素诱导细胞建立胰岛素抵抗模型,给予不同浓度D-手性肌醇及D-松醇,考察二者对胰岛素抵抗HepG2细胞葡萄糖消耗量的影响。实验结果表明,在200~1000 mg/L的浓度范围内D-手性肌醇和D-松醇对HepG2细胞的正常增殖无显著影响。D-手性肌醇浓度为50、100和200 mg/L时,对胰岛素抵抗HepG2细胞的葡萄糖消耗量与模型对照组相比有显著促进作用(p0.05),浓度为400 mg/L时,有极显著性差异(p0.01);D-松醇浓度为200 mg/L时,对胰岛素抵抗HepG2细胞的葡萄糖消耗量与模型对照组相比有显著促进作用(p0.05),浓度为400 mg/L时,有极显著性差异(p0.01)。因此,D-手性肌醇和D-松醇均能够缓解HepG2细胞胰岛素抵抗现象,且在1000 mg/L浓度范围内对HepG2细胞正常增殖无显著影响。     

Investigation of selected toxicological parameters of γ-pentachlorocyclohexene (γ-PCCH)

The toxic effects of the γ-hexachlorocyclohexane metabolite γ-pentachlorocyclohexene (γ-PCCH) were studied by acute and subacute (6 weeks) experiments. The investigations included cerebral convulsibility with chemoshock (Tetrazolium), reactivity with hot plate method, the learning ability with learning tests, and peripheral nervous activity (EMG). Nociceptive reaction time was not influenced, the learning process (6 weeks) was inhibited by γ-PCCH. The conduction velocity of the peripheral nerve was decreased. At the end of the 6th week liver enlargement was found.     

3-苄硫基噻吩、3-糠硫基噻吩和3-十二烷硫基噻吩的合成及其香气特征

-40℃下,3-溴噻吩先与n-丁基锂反应,再依次加入碘、活性镁粉和二硫醚,在室温下分别反应4、4.5、4.5h,分别合成3-苄硫基噻吩、3-糠硫基噻吩和3-十二烷硫基噻吩,收率分别为51.1%、29.0%和27.4%.这些化合物结构都通过IR、MS和~1HNMR测试技术进行了表征,并对其进行了初步香味评价.结果表明,它们都具有基本肉香味特征,阈值为19.78～30.11mg·kg~(-1),留香时间可达2.5～3.5h.     

Cystathionine γ-lyase of Saccharomyces cerevisiae: Structural gene and cystathionine γ-synthase activity

Purification of Saccharomyces cerevisiae cystathionine γ-lyase (γ-CTLase) was hampered by the presence of a protein migrating very close to it in various types of column chromatography. The enzyme and the contaminant were nevertheless separated by polyacrylamide gel electrophoresis. N-terminal amino acid sequence analysis indicated that they are coded for by CYS3(CYI1) and MET17(MET25), respectively, leading to the conclusion that CYS3 is the structural gene for γ-CTLase and that the contaminant is O-acetylserine/O-acetylhomoserine sulfhydrylase (OAS/OAH SHLase). Based on these findings, we purified γ-CTLase by the following strategy: (1) extraction of OAS/OAH SHLase from a CYS3-disrupted strain; (2) preparation of antiserum against it; (3) identification of a strain devoid of the OAS/OAH SHLase protein using this antiserum; and (4) extraction of γ-CTLase from this strain. Purified γ-CTLase had cystathionine γ-synthase (γ-CTSase) activity if O-succinylhomoserine, but not O-acetylhomoserine, was used as substrate. From this notion we discuss the evolutional relationship between S. cerevisiae γ-CTLase and Escherichia coli γ-CTSase.     

Comparative study of enzymatic hydrolysis of α/β- and γ-gliadins

Enzymatic hydrolysis of proteins and fractionation of hydrolysates is a route of diversifying their functional properties. Chymotryptic hydrolysis of different sulphur-rich gliadins (α/β- and γ-types), major wheat storage proteins, was studied. The peptides formed in the course of digestion were characterised by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate (SDS-PAGE) and reversed-phase high performance liquid chromatography (RP-HPLC). With reference to previous work, a general scheme of degradation was assessed for γ-gliadins. Limited hydrolysis released two types of polypeptides, comprising respectively the repetitive and the non-repetitive moieties of the protein. In spite of strong sequence homologies between the two groups of sulphur-rich gliadins, it was not possible to prepare similar peptide fractions from α/β-gliadins. They were more resistant to hydrolysis and the region where the two domains merge appeared inaccessible to chymotrypsin. Restricted accessibility of cleavage sites was attributed to the less expanded conformation of α/β-type than γ-type gliadins. A first step of scaling-up was performed. This offers opportunities to prepare functional peptides from wheat storage proteins.     

Products of Thermal Degradation of the Anthocyanins Cyanidin-3-glucoside,Cyanidin-3-rutinoside and Cyanidin-3-sophoroside

During thermal degradation of anthocyanins, cyanidin-3-glucoside, cyanidin-3-rutinoside, cyanidin-3-sophoroside, at 98 °C in model systems of pH = 1, 2.5 3.5 and 4.5, seven compounds were isolated by means of paper chromatography. Among them quercetin, phloroglucin-aldehyde and protocatechuic acid were identified.     

Yeast 14-3-3 proteins

14-3-3 proteins form a family of highly conserved proteins which are present in all eukaryotic organisms investigated, often in multiple isoforms, up to 13 in some plants. They interact with more than 200 different, mostly phosphorylated proteins. The molecular consequences of 14-3-3 binding are diverse: this binding may result in stabilization of the active or inactive phosphorylated form of the protein, to a conformational alteration leading to activation or inhibition, to a different subcellular localization, to the interaction with other proteins or to shielding of binding sites. The binding partners, and hence the 14-3-3 proteins, are involved in almost every cellular process and 14-3-3 proteins have been linked to several diseases, such as cancer, Alzheimer's disease, the neurological Miller-Dieker and spinocerebellar ataxia type 1 diseases and bovine spongiform encephalopathy (BSE). The yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe both have two genes encoding 14-3-3 proteins, BMH1 and BMH2 and rad24 and rad25, respectively. In these yeasts, 14-3-3 proteins are essential in most laboratory strains. As in higher eukaryotes, yeast 14-3-3 proteins bind to numerous proteins involved in a variety of cellular processes. Recent genome-wide studies on yeast strains with impaired 14-3-3 function support the participation of 14-3-3 proteins in numerous yeast cellular processes. Given the high evolutionary conservation of the 14-3-3 proteins, the experimental accessibility and relative simplicity of yeasts make them excellent model organisms for elucidating the function of the 14-3-3 protein family.     

织物三维悬垂形态测试指标与三维重建

针对织物悬垂指标实际应用滞后于理论研究和指标的繁杂冗余问题,介绍了自行研制的织物悬垂三维形态测试仪及其测试指标。在分析和优化前人研究成果基础上,提出可以较好反映织物悬垂性能的2个综合指标——匀称度和美感指数,分别表征织物悬垂性能和悬垂形态。通过与现有的各主要测量指标进行对比分析,认为美感指数与主观经验评判标准更具一致性。利用悬垂系数、波纹数、匀称度、三维系数指标,尝试重现三维悬垂形态,获得了更直观的视觉效果。