Expression of α-1,6-dextranase from Penicillium minioluteum in P.pastoris

α-1,6-葡聚糖酶是专一作用于α-1,6糖苷键产生小分子葡聚糖的一类水解酶,广泛的运用于制糖工业和啤酒工业中。采用PCr法扩增朱黄青霉(PEnICIllIuM MInIOluTEuM)C12114的α-1,6-葡聚糖酶基因,将其插入毕赤酵母表达载体PPIC9k。经SACI酶线性化电击转入毕赤酵母基因组,构建重组酵母gS115/PPIC9k-dEX。对构建成功的转化子进行1.5%的甲醇诱导表达,在30℃条件下培养7d时酶活达到最大值,为88.35u/Ml。α-1,6-dextranase,which can hydrolyze dextran specifically by cutting off the α-1,6-glycosidic bond to release shorter saccharides,was widely used in many fields such as sugar industry and beer industry.The gene of α-1,6-dextranase(dex)was amplified through PCR by using Penicillium minioluteum C12114 genomic DNA as template.The amplified gene was cloned into vector pPIC9K and the recombinant plasmid pPIC9K-dex was linearzed with Sac I,then transformed into P.pastoris GS115 by electroporation.The positive transformant was induced to express the enzyme with 1.5% methanol for 7 days under the 30℃,and the activity of the enzyme could reach 88.35U/mL.广东省科技计划项

THE EXPERIMENTAL STUDY ON EFFECTS of TEA POLYPHENOLS AGAINST HYPERURICEMIA IN RATS

目的观察茶多酚(TP)对高尿酸血症大鼠体内尿酸水平的影响,探讨其降低血尿酸作用的可能机制。方法取雄性Sd大鼠30只,分为空白对照、高尿酸血症模型、TP低、中、高剂量5组,每组6只。对模型组及TP干预组大鼠灌胃给以15 g/kg·d酵母膏、200 Mg/kg·d腺嘌呤及30 Mg/kg·d氧嗪酸钾联合造模30d;TP干预组在造模10d后灌胃给予TP,连续20d,剂量分别为100、200、300 Mg/kg·d,模型组继续灌胃造模剂,空白组灌胃等量生理盐水。实验结束时,测定血液和尿液中的尿酸(uA)、肌酐(Cr)及尿素氮(un)含量,检测肝脏和血清中的黄嘌呤氧化酶(XOd)活性以及尿酸排泄分数(fEuA)。结果模型组血尿酸水平较空白对照组明显升高(P0.05);模型组肝脏XOd活性明显高于空白对照组(P0.05).The activity of XOD in liver in model group was significantly higher than those of the controls(P<0.01), and lower in low dose group than those of the model group(P<0.05).The FEUA level of rats in medium group was higher than those of the controls and models(P<0.005).Conclusion Tea polyphenols reduce blood uric acid level in rats with hyperuricemia and the related mechanism may be associated with its inhibition on the activity of XOD in liver

两段循环流化床吸附有机气体实验

以Ambersorb600为吸附剂,甲苯为吸附质,在两级循环流化床吸附装置内进行了吸附特性的实验.采用PGM7600型VOCs分析仪测量甲苯的浓度,得到两段循环流化床的压力和空隙率分布及浓度随床高的分布;研究了气体进口浓度和表观气速对吸附效率的影响.在实验条件下吸附装置效率为95%~98%

两段循环流化床吸附有机气体实验

以Ambersorb 600为吸附剂，甲苯为吸附质，在两级循环流化床吸附装置内进行了吸附特性的实验．采用PGM-7600型VOCs分析仪测量甲苯的浓度，得到两段循环流化床的压力和空隙率分布及浓度随床高的分布；研究了气体进口浓度和表观气速对吸附效率的影响．在实验条件下吸附装置效率为95％～98％

Wave loads on high-rise pile cap structures and mitigation approach

A 11el type of foundation, a high-rise pile cap structure, was proposed to support offshore wind turbines in China. It is unique because the upper cap is now and then partially submerged or totally exposed in the air. The wave force of this unique structure is not well understood yet. In this paper, a fully nonlinear numerical wave tank is established to deal with this problem based on Navier-Stokes equations and volume of fluid technique. The wave impact loads on the structure and their mechanism are revealed. Modifications of the cap bottom elevation are considered to explore its influence on direct and indirect wave impact loads on the lower piles. The wave impact load on the most dangerous pile is detected high if the cap bottom is at the still water level or close to the wave crest level, and small impact load is found while the cap bottom is at the height of half wave crest. Attempts of structural improvement are considered to reduce the wave impact loads on the piles. The wave impact load can be notably reduced by opening air vents in the cap together with lifting the bottom of the inner part of the cap

世界芝麻生产现状与我国芝麻生产发展趋势分析Production status of the world sesame and development trend of sesame production in China

芝麻是世界上最古老的油料作物之一，也是我国重要的优质特色油料作物，其在国际油料产业发展中居于重要地位。我国既是芝麻生产大国，也是消费大国。综述了世界芝麻生产与贸易现状、主产国及其芝麻种植区域分布，栽培品种现状，分析了世界芝麻生产中存在的问题和我国芝麻生产发展趋势。芝麻市场刚性需求、政策支持和生产技术进步及农业“走出去”战略和“一带一路”倡议，将会进一步促进我国芝麻产业发展并提升其在国际芝麻贸易中的地位。Sesame is one of the oldest oilseed crops in the world，and it is an important and specific oilseed crop with high quality in China. Sesame plays an important role in the development of international oilseed industry. China is both a major producer and consumer of sesame. The status of sesame production and trade,the major producing countries and their sesame planting areas distribution,and cultivated variety status of the world were clarified, the problems existing in the world sesame production and the development trend of sesame production in China were analyzed. The rigid demand of sesame, policy support and production technology progress, as well as the agricultural "go out" strategy and "the Belt and Road" initiative, will further promote the development of China′s sesame industry and enhance its status in the international sesame trade

体外诱导小鼠胚胎干细胞分化为心肌细胞的初步研究

目的：5-氮胞苷作为分化诱导剂，初步探讨其单独或联合全反式维甲酸应用时对小鼠胚胎干细胞(mESC)分化为心肌细胞的影响，旨在建立一种体外诱导mESC分化为心肌细胞的实验方法。方法：采用MTT法确定5-氮胞苷的非细胞毒性参考剂量。设计不同条件培养基(5-氮胞苷单独或配伍全反式维甲酸应用)对mESC进行诱导分化，并通过免疫组化技术及RT—PCR方法等对分化细胞进行鉴定。结果：5-氮胞苷的非细胞毒性参考剂量为8μmol／L，能够诱导mESC分化为心肌合胞体(与阴性对照组比较，P 0．05)：即对ESC向心肌细胞的诱导分化没有促进作用。结论：5-氮胞苷能够诱导mESC分化为心肌合胞体，从而得以建立一种体外诱导mESC分化为心肌细胞的方法

阳离子脂质体基因载体的细胞转染研究

研究阳离子脂质体在不同细胞中的转染效率及毒性。首先采用DNA延滞实验研究Lipofectamine2000、DOTAP转染试剂与DNA的结合能力。然后选用绿色荧光蛋白的质粒pGFP-N2作为报告基因模型和转染试剂制成复合物后转染Hela、7721、HT29细胞，比较多种因素对转染的影响。最后使用MTT比色法分析Lipofectamine2000、DOTAP转染试剂对细胞的毒性。随着复合物中转染试剂比例的增加，Lipofectamine2000、DOTAP与DNA结合能力逐渐增强。Lipofectamine2000在Hela细胞转染最高效率约72％；在7721、HT29细胞转染效率较低。DOTAP在3种细胞的转染效率都很低；在转染效率最高时2种转染试剂的细胞存活率均在90％以上。对商品化的转染试剂研究和讨论以期为阳离子类脂非病毒载体的研究提供参考

阳离子脂质体基因载体的细胞转染研究

研究阳离子脂质体在不同细胞中的转染效率及毒性。首先采用DNA延滞实验研究Lipofectamine2000、DOTAP转染试剂与DNA的结合能力。然后选用绿色荧光蛋白的质粒pGFP-N2作为报告基因模型和转染试剂制成复合物后转染Hela、7721、HT29细胞，比较多种因素对转染的影响。最后使用MTT比色法分析Lipofectamine2000、DOTAP转染试剂对细胞的毒性。随着复合物中转染试剂比例的增加，Lipofectamine2000、DOTAP与DNA结合能力逐渐增强。Lipofectamine2000在Hela细胞转染最高效率约72％；在7721、HT29细胞转染效率较低。DOTAP在3种细胞的转染效率都很低；在转染效率最高时2种转染试剂的细胞存活率均在90％以上。对商品化的转染试剂研究和讨论以期为阳离子类脂非病毒载体的研究提供参考