Inhibition of mitochondrial complex I improves glucose metabolism independently of AMPK activation

Accumulating evidences showed metformin and berberine, well‐known glucose‐lowering agents, were able to inhibit mitochondrial electron transport chain at complex I. In this study, we aimed to explore the antihyperglycaemic effect of complex I inhibition. Rotenone, amobarbital and gene silence of NDUFA13 were used to inhibit complex I. Intraperitoneal glucose tolerance test and insulin tolerance test were performed in db/db mice. Lactate release and glucose consumption were measured to investigate glucose metabolism in HepG2 hepatocytes and C2C12 myotubes. Glucose output was measured in primary hepatocytes. Compound C and adenoviruses expressing dominant negative AMP‐activated protein kinase (AMPK) α1/2 were exploited to inactivate AMPK pathway. Cellular NAD⁺/NADH ratio was assayed to evaluate energy transforming and redox state. Rotenone ameliorated hyperglycaemia and insulin resistance in db/db mice. It induced glucose consumption and glycolysis and reduced hepatic glucose output. Rotenone also activated AMPK. Furthermore, it remained effective with AMPK inactivation. The enhanced glycolysis and repressed gluconeogenesis correlated with a reduction in cellular NAD⁺/NADH ratio, which resulted from complex I suppression. Amobarbital, another representative complex I inhibitor, stimulated glucose consumption and decreased hepatic glucose output in vitro, too. Similar changes were observed while expression of NDUFA13, a subunit of complex I, was knocked down with gene silencing. These findings reveal mitochondrial complex I emerges as a key drug target for diabetes treatment. Inhibition of complex I improves glucose homoeostasis via non‐AMPK pathway, which may relate to the suppression of the cellular NAD⁺/NADH ratio.     

鱼腥藻PCC7120藻蓝蛋白α亚基体内重组研究

为了研究藻蓝蛋白α亚基的生物合成途径,通过构建相容的3种重组质粒pETDuet-cpcA、pCOLADuet-cpcE-cpcF和pACYCDuet-ho1-pcyA,将裂合酶基因cpcE和cpcF、血红素氧化酶基因ho1、藻蓝胆素合成酶基因pcyA和脱辅基藻蓝蛋白α亚基基因cpcA共同转入大肠杆菌BL21(DE3)。通过色素蛋白锌电泳和光谱检测表明产生了生物活性的CpcA-PCB。成功实现了大肠杆菌内藻蓝蛋白α亚基84位半胱氨酸残基与PCB的连接。而在裂合酶基因cpcE和cpcF不转入大肠杆菌的情况下,大肠杆菌内只有0.2%的CpcA-PCB产生。以上研究为进一步在大肠杆菌内合成天然的藻蓝蛋白奠定了基础。     

草鱼呼肠孤病毒在CIK细胞中复制及形态发生的研究

以草鱼呼肠孤病毒（ＧＣＲＶ）感染的草鱼肾细胞系（ＣＩＫ）为模型,进行了草鱼呼肠孤病毒在细胞内的形态发生的研究。当病毒以感染复数为５￣１０ＰＦＵ／ＣＥＬＬ感染ＣＩＫ细胞时,在病毒感染细胞４ｈ以内的切片中,可观察到脱去部分外层衣壳的不完整病毒颗粒。感染细胞８ｈ,可观察到浆胞内病毒发生基质,其内含有大量的直径约５０ｎｍ的亚病毒颗粒,无外层蛋白结构。感染１２￣１６ｈ后,这些亚病毒颗粒装配上外层蛋白结构,形     

尾叶桉人工林生物量和生产力的研究

按径级标准木法测定了尾叶桉（Ｅｕｃａｌｙｐｔｕｓ ｕｒｏｐｈｙｌｌａ）器官生物量,建立了林木器官干重（ｗ）与胸径和树高（Ｄ＾３Ｈ）关系的相对生长方程,进而计算出尾叶桉林分的生物量和生产力。结果表明：东门林场１０年生尾叶桉人工林平均生物量为１４４．８５ｔ ｈｍ＾２,各器官生物量的在小序列为：干材（７１．６９％）〉根（１４．２１％）〉皮）７．９９％）〉枝（４．７１％）〉叶（４．７１％）〉叶（１．４０％     

Use of galactosyltransferase to assess the biological function of O-linked N-acetyl-d-glucosamine: a potential role for O-GlcNAc during cell division

Many cytosolic and nuclear proteins are modified by monomeric O-linked N-acetyl-d-glucosamine (O-GlcNAc). The biological functions of this form of glycosylation are unclear but evidence suggests that it heightens regulation of protein function. To assess the biological function of O-GlcNAc addition, we examined the biological effects of galactosyltransferase (GalT) microinjected into the cytoplasm of Xenopus ovarian oocytes. GalT, which catalyzes beta1-4-galactose addition to O-GlcNAc, should inhibit deglycosylation and lectin-like interactions requiring unmodified O-GlcNAc residues. Although GalT injection into diplotene-arrested oocytes has no detectable effects on cell viability, it is toxic to oocytes entering meiosis. Cell-cycle-specific toxicity is recapitulated in vitro as GalT inhibits formation of nuclei and microtubule asters from cell-free extracts of ovulated frog eggs. These observations suggest that regulation of O-GlcNAc is important for cell cycle progression and may be important in diseases in which O-GlcNAc metabolism is abnormal. The methods described here outline a viable experimental scheme for ascribing a biological function to this form of glycosylation.     

巴氏杆菌糖酵解酶的黏附作用研究

巴氏杆菌（主要是多杀性巴氏杆菌）可以引起多种动物疫病（巴氏杆菌病）,同时也引起人类感染发病。[目的] 研究巴氏杆菌糖酵解酶对宿主细胞（兔肾细胞）和两种常见分子[纤连蛋白（fibronectin,Fn）和血浆纤维蛋白溶解酶原（plasminogen,Plg）]的黏附作用。[方法] 采用原核表达系统对多杀性巴氏杆菌的糖酵解酶进行表达并纯化及制备多克隆抗体,通过菌体表面蛋白定位检测、黏附与黏附抑制等实验探究巴氏杆菌糖酵解酶的黏附作用。[结果] 菌体表面蛋白检测结果显示除烯醇化酶和丙酮酸激酶外的7个糖酵解酶在多杀性巴氏杆菌表面存在。这7个糖酵解酶均能黏附兔肾细胞,但仅有磷酸葡萄糖异构酶的多克隆抗体能对多杀性巴氏杆菌黏附宿主细胞产生抑制作用。Far Western blotting结果显示9个糖酵解酶均能结合宿主Fn和Plg。招募抑制实验结果显示磷酸葡萄糖异构酶、醛缩酶、磷酸甘油酸变位酶的抗体对多杀性巴氏杆菌结合Fn和Plg都有抑制作用,磷酸果糖激酶、丙糖磷酸异构酶、甘油醛-3-磷酸脱氢酶、磷酸甘油激酶抗体仅对多杀性巴氏杆菌结合Fn或Plg有抑制作用。[结论] 多杀性巴氏杆菌糖酵解酶成员葡萄糖异构酶、磷酸果糖激酶、醛缩酶、丙糖磷酸异构酶、甘油醛-3-磷酸脱氢酶、磷酸甘油激酶、磷酸甘油酸变位酶在多杀性巴氏杆菌黏附宿主细胞或分子过程中发挥作用。该研究的完成将加深巴氏杆菌病分子发病机制的认识,并为巴氏杆菌病的诊断标识筛选、新型疫苗创制和药物靶标筛选等提供基础数据。     

雷氏大疣蛛毒素—Ⅱ的纯化与初步毒性研究

雷氏大疣蛛是我国最近鉴定的蜘蛛新种。雷氏大疣蛛毒素－Ⅱ就是以其粗毒为材料,利用阴、阳离子交换层析和反相HPLC分离得到并命名的一种新型神经毒素肽,根据质谱分析得知它的相对分子质量为3021．56;通过初步毒性研究,证明它是一个神经毒素。     

中药山豆根的研究进展

本文对中药山豆根进行了本草考证,并概括总结了半个世纪以来国内外对山豆根(广豆根)和北豆根在生药学研究、化学成分、药理作用与临床应用等方面的研究成果,为山豆根的进一步研究提供参考。全文附参考文献105篇。     

Passive protective effect of egg-yolk antibodies against enterotoxigenic Escherichia coli K88+ infection in neonatal and early-weaned piglets

The protective effects of egg-yolk antibodies obtained from hens immunized with fimbrial antigens from a local strain (Escherichia coli K88+ MB, Manitoba, Canada) of K88+ piliated enterotoxigenic E. coli (ETEC) were evaluated in 3- and 21-day-old piglets in which ETEC diarrhea was induced and also in early-weaned piglets in a commercial farm. The results demonstrated that the E. coli K88+ MB-induced diarrhea in 3-day-old piglets was cured 24 h after treating with egg-yolk antibodies while those treated with egg-yolk powder from conventional hens continued to have diarrhea and 62.5% of them died of severe diarrhea. For 21-day-old weaned piglets, those fed egg-yolk antibodies had transient diarrhea, positive body weight gains and 100% survival during the period of the experiment, whereas control piglets that were treated with placebo had severe diarrhea and dehydration and some died within 48 h after infection. In the field trial, the incidence and severity of diarrhea of 14-18-day-old weaned piglets fed egg-yolk antibodies were much lower than in those fed a commercial diet containing an antibiotic. These results indicate that the neonatal and early-weaned piglets that received the egg-yolk antibodies were protected against ETEC infection.     

Lipidomic changes during different growth stages of Nitzschia closterium f. minutissima

Ultra Performance Liquid Chromatography-Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry (UPLC-ESI-Q-TOF–MS) is a powerful lipidomic tool. In this study, we developed a UPLC/Q-TOF–MS based method to investigate the lipid metabolomic changes in different growth phases of Nitzschia closterium f. minutissima. The data classification and biomarker selection were carried out by using multivariate statistical analysis, including principal components analysis (PCA), projection to latent structures with discriminant analysis (PLS-DA), and orthogonal projection to latent structures with discriminant analysis (OPLS-DA). We discovered that the intercellular lipid metabolites were significantly different among exponential, early stationary and late stationary phases. Thirty-one lipid molecules were selected and identified as putative biomarkers, including free fatty acid, Harderoporphyrin, phosphatidylglycerol, 1,2-diacyglycerl-3-O-4′-(N,N-trimethy)-homoserine, triacylglycerol, cholesterol, sulfoquinovosyldiacylglycerol, lyso-sulfoquinovosyldiacylglycerol, monogalactosyldiacylglycerol, digalactosyldiacylglycerol and lyso-digalactosyldiacylglycerol. These lipids have been shown previously to function in energy storage, membrane stability and photosynthesis efficiency during the growth of diatoms. Further analysis on the putative biomarkers demonstrated that nitrate starvation played critical role in the transition from exponential phase to stationary phase in N. closterium. This study is the first one to explore the lipidomic changes of microalgae in different growth phases, which promotes better understanding of their physiology and ecology.