Effect of Decrystallization of Cellulose on Adsorbing Cellulase

为探讨解结晶处理提高酶水解效率的机理,对比研究了高结晶度的微晶纤维素(MCC)和低结晶度的解结晶微晶纤维素(D-MCC)对纤维素酶的吸附过程。结果发现:酶吸附平衡后,样品的XPS和FT-IR分析表明纤维素酶通过酶蛋白的氨基(—NH_2)与纤维素分子链上的羟基(—OH)之间以氢键(C—OH…NH)力吸附在MCC上;相同条件下得到的MCC和D-MCC吸附率曲线的差异表明,底物结构的改善比提高温度更能提高酶吸附率;比较纤维素酶对MCC和D-MCC在35℃下的吸附动力学可知,通过降低底物的结晶度可促进酶吸附,刚性结构的MCC更满足准一级动力学的假设,D-MCC表面结构相对松散,其吸附过程需进一步分析,以得到更适合的动力学方程。The cellulase adsorbed and formed enzyme-substrate( ES) compound is a key step in the process of enzymatic hydrolysis. Through the comparison of cellulase adsorbed on two substrates: microcrystalline cellulose( MCC) with high degree of crystallinity and decrystallization microcrystalline cellulose( D-MCC) with low degree of crystallinity,it was found that,in the XPS wide scan patterns of adsorption equilibrium MCC,a new absorption peak of nitrogen element( 399. 06 e V) was observed. The fitting method is adopted to treat the strong peak of XPS-O1 s,and the binding energy of this new peak was only 530. 53 e V. In the infrared absorption range of 3050- 3550 cm~(- 1),the absorption intensity of OH group decreased with extending adsorption time on cellulose. The above results proved that new hydrogen bonds( C—OH…NH) between the protein amino( —NH_2) and cellulose molecule chain( —OH) were generated during the cellulose adsorption process. From the comparison of the adsorption rate curves between MCC and D-MCC,the decrystallization method to improve cellulase adsorption was more effective than enhancing the temperature. From the comparison of adsorption kinetics between MCC and D-MCC at 35℃,it was indicated that a reduction of cellulose crystallinity was positive for adsorption rate. MCC with rigid surface was fit for the first-order kinetic hypothesis. D-MCC with flexible surface was not suitable for the first-order kinetic. A more suitable kinetic hypothesis should be investigated in the future.国家自然科学基金-广东自然科学基金联合基金重点项目(U0733001

Discussion on effective enzymatic hydrolysis of cellulose

纤维素酶解可为生物质基的能源与化工品开发提供必需的水溶性还原糖。实验以浓磷酸解结晶处理结合纤维素酶-β-葡萄糖苷酶混合酶液的协同酶解,构建了一种高效酶解方法。实验结果表明,酶水解的最佳条件为:酶液质量浓度为0.062 5 Mg/M l,底物质量浓度为12.5 Mg/M l,P H为4.8缓冲溶液,酶解温度为50℃,转速为120 r/MIn。解结晶MCC结合协同酶解方法作用120 H和解结晶麦草结合协同酶解方法作用120 H,产物得率均得到大幅提高。Enzymatic hydrolysis can provide necessary soluble reducing sugars for biomass based energy and chemicals.An effective enzymatic hydrolytic method is established by using the concentrated phosphoric acid to decrystallize the microcrystalline cellulose( MCC) and wheat straw,and cellulose to mix with β-Glucosidase.The optimal enzymatic hydrolysis conditions are shown as follows: 0.062 5 mg / m L of cellulose,12.5 mg / m L of substrate,p H 4.8 of citric acid buffer solution,50℃ of enzymolysis temperature and 120 r / min of shaking speed.The yields are both greatly improved for decrystallization of MCC / enzymolysis and decrystallization of wheat straw / enzymolysis for 120 hours.中山市科技技术项目(2014A2FC333); 电子科技大学中山学院科研团队培育项目(412YT02

“动物酵素营养液”对奶牛乳房炎及产奶量的影响

为验证基础日粮中添加0.8%“京福龙“动物酵素营养液对奶牛乳房炎及产奶量的影响。选择不同牧场的荷斯坦奶牛300头进行试验,结果显示,试验组没有出现乳房炎,且产奶量明显增加。试验期间,A组试验的试验组较对照组每头奶牛增加经济效益达3306.4元,b组试验的试验组较对照组每头奶牛增加经济效益达4578.4元

束缚和异氟烷麻醉对大鼠心率变异性及HPA轴影响的比较

目的为了观察束缚固定和异氟烷(流量:0.8 L,浓度:1.5%)麻醉状态中大鼠的心率变异性的变化;并通过比较9天每天30 min束缚干预和异氟烷麻醉对大鼠的体重、痛阈以及与HPA轴相关激素的影响,来评估长期使用异氟烷麻醉和束缚固定对大鼠应激程度的影响,选择更适宜的大鼠固定方法,为基础医学的实验方法提供重要的参考。方法 SD大鼠随机分为3组:空白组,束缚组,异氟烷麻醉组。急性实验通过记录大鼠心电图15 min,观察束缚固定和异氟烷麻醉情况下大鼠心率,心率变异性的变化。慢性实验中比较连续干预9天(30 min/d)前后3组大鼠体重、痛阈变化以及与应激状态相关激素含量的变化。结果 1)急性试验:与空白组大鼠相比,束缚干预和异氟烷麻醉均造成大鼠心率显著增加,具有统计学意义(P 0.05)。结论以上结果提示:低浓度的异氟烷造成麻醉中大鼠心率增加,心率变异性下降,产生以交感兴奋为主的自主神经功能状态改变。多次束缚固定易造成大鼠HPA轴激活,产生慢性应激的效应。在长期需要固定动物的实验中,与束缚固定相比异氟烷麻醉是更好的固定方法。国家自然科学基金(81674083

中国医务人员医疗标准执行现况及影响因素调查

目的调查我国医务人员医疗标准执行现况及其影响因素,进而了解标准未完全执行的原因。方法采用多阶段分层抽样法,通过实地和网络问卷调查相结合的方式,根据国家统计局地区划分标准,共招募了中国东部、中部、西部和东北4个地区共抽取10375名医务人员填写问卷。结果中国医务人员自我报告的对专业范围内已发布的标准执行率为82.2%。样本医务人员对医疗标准执行率上存在地区(Wald=10.973,P<0.05)、机构级别(Wald=95.052,P<0.01)以及标准认可程度(Wald=689.166,P<0.01)间存在差异。结论中国医务人员对所在专业范围内已经发布的相关标准的自我报告执行程度较高。国家卫健委医疗相关标准调查(2018-65

300kg/a规模流化床制碳纳米管中试研究

采用Ni-Mg-O复合氧化物催化剂进行了流化床甲烷催化裂解法制碳纳米管的中试实验,研究了主要操作变量对甲烷转化率、催化剂产碳率、产品团聚率及催化剂损失率的影响,得到了适宜的操作条件为:甲烷进气流速16～19 cm/s、催化剂粒径150～220μm、催化剂加入量50～60 g、反应温度650～700℃、反应时间120～140 min。多批次重复性实验表明,在选定的操作条件下,甲烷转化率约为30%,催化剂产碳率约为10 gCNTs/gCAT。对纯化后的产品进行SEM及TEM形貌表征显示,制得的碳纳米管管径均匀,中空结构明显,碳纳米管的外径为10～30 nm,内径为2～5 nm。中国海洋石油总公司科技项目(CNOOC-KJ125FZDXM00TJY001-2014

Regulation effect of exogenous nitric oxide on anti-oxidation system of Kandelia candel seedlings treated with NaCl

研究了外源一氧化氮(NO)供体硝普钠(SNP)对NaCl处理下红树植物秋茄(Kan-deliacandel)幼苗叶片中抗氧化酶活性、抗氧化物质及脯氨酸含量的影响。结果表明:NaCl处理下,秋茄幼苗叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)等4种活性氧清除酶的活性均受到明显抑制(P<0.05),SNP可以不同程度地恢复SOD、POD、CAT的活性,但对APX活性影响不大;SNP提高谷胱甘肽(GSH)及类胡萝卜素(Car)的含量,促进脯氨酸含量的上升,显著降低叶片中过氧化氢(H2O2)和丙二醛(MDA)的累积。表明外源NO可以缓解NaCl处理诱导的秋茄幼苗叶片氧化损伤,降低膜脂过氧化水平,有利于秋茄适应盐生环境。By using sodium nitroprusside(SNP)as the donor of exogenous nitric oxide,this paper studied its effects on the antioxidant enzyme activities,anti-oxidation substances,and proline content in the leaves of Kandelia candel seedlings treated with NaCl.The results showed that after treated with NaCl,the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)and ascorbate peroxidase(APX)in K.candel seedling leaves were depressed significantly(P<0.05),while SNP could recover the activities of SOD,POD and CAT to different degrees but showed little effect on APX.SNP increased the contents of glutathione(GSH)and carotenoid(Car),promoted the production of proline,and decreased the accumulation of H2O2 and malondialdehyde(MDA)significantly.It was indicated that SNP could relieve the oxidation damages induced by NaCl via decreasing the level of membrane lipid peroxidation in K.candel leaves,and facilitate K.candel to adapt to saline environment.国家自然科学基金项目(30670317和39970438);; 厦门大学新世纪优秀人才支持计划项目(0000-X07115)资

使用FLAG标签肽及慢病毒载体共同筛选小鼠foxp3基因RNA干扰的有效靶点

【目的】筛选高效的foxp3 RNA干扰的靶点用于阻断CD4^＋CD25^＋ Treg细胞的免疫抑制功能。【方法】使用oligoengine软件设计foxp3基因shRNA序列，化学合成法合成4条shRNA序列，构建含foxp3的靶序列的慢病毒载体：构建出表达FLAG融合蛋白和目的基因的工具细胞293T细胞用于筛选RNA干扰的有效靶点。【结果】成功包装了4条foxp3基因靶序列相应的慢病毒颗粒；成功构建了表达融合蛋白和目的基因的293T工具细胞：在工具细胞上筛选出了2条RNAi效率分别为91.3％和95．6％的有效靶点。【结论】使用FLAG融合蛋白和慢病毒载体能够筛选出Foxp3基因的RNAi最佳靶点

近海生态系统碳汇过程、调控机制及增汇模式

海洋是地球上最大的碳库,发挥着全球气候变化缓冲器的作用.蓝色碳汇,简称蓝碳,即由海洋生态系统捕获的碳(主要是有机碳),是海洋储碳的重要机制之一.; 蓝碳最初认识的形式是可见的海岸带植物固碳.其实之前没有得到足够重视的、看不见的微型生物(浮游植物、细菌、古菌、病毒、原生动物)占海洋生物量90%; 以上,是蓝碳的主要贡献者.中国陆架边缘海占国土总面积的1/3,碳汇潜力巨大,亟待研发.本文以近海生态系统碳汇过程、调控机制及增汇模式为主线,论述; 了近海生态系统结构与碳循环功能特征、碳汇形成过程与机理,并结合近海碳汇在沉积记录中的地史过程演变探讨了自然过程和人类活动对碳汇的可能影响,展望了; 碳汇工程在增加近海海洋储碳能力方面的应用前景.国家重大科学研究计划项目; 国家重点研发计划项目; 国家自然科学基金项目; 国家海洋局全球变化与海气相互作用专项项

Preparation and application of monoclonal antibodies against Herpes simplex virus-1

目的:制备并筛选HSV-1单抗,建立定量检测HSV-1病毒颗粒抗原的双抗体夹心ElISA方法,用于HSV-1病毒颗粒的质控。方法:以HSV-1免疫bAlb/C小鼠制备单克隆抗体,以筛选的中和单克隆抗体1f6为捕捉抗体,HrP标记的2b1为检测抗体,构建定量检测HSV-1病毒颗粒抗原的双抗体夹心ElISA方法,并对本方法的特异性、灵敏度、精密度、准确性和线性等性能进行验证。用本方法定量检测的病毒量与病毒滴度作回归分析。结果:构建的双抗体夹心定量检测HSV-1病毒颗粒抗原的ElISA方法,线性范围为0.125~2μg/Ml,相关系数为r2=0.995 5,定量限度为0.125μg/Ml,试剂的变异系数CV<10%,抗原回收率介于85.6%~107.1%之间。与HSV-1以外的其他样本无交叉反应。本方法检测与病毒感染滴度具有很好的相关性。结论:成功构建了定量检测HSV-1含量的ElISA方法,为HSV-1病毒颗粒抗原定量检测提供快速手段。Objective: To prepare and screen monoclonal antibodies against Herpes simplex virus-1( HSV-1),and develop a double antibody sandwich quantitative enzyme-linked immunosorbent assay( Q-ELISA) for detection of HSV-1 particle.This method was used to control the quality of viral particle in the developing and manufacturing process of HSV-1.Methods: BALB / c mice was immunized with HSV-1 to prepare monoclonal antibodies.A double antibody sandwich Q-ELISA was developed to determine concentration of HSV-1 particle,which was based on the neutralizing monoclonal antibody 1F6 as capture antibody,and 2B1 as HRP-conjugated antibody.The performance of the reagent was evaluated,including specificity,sensitivity,precision,accuracy and linear.And the relation between the amount of virus detected by this method and the virus titer was analyzed by regression analysis method.Results: The QELISA for HSV-1 particle was developed.The quantitation scope was 0.125- 2 μg / ml,the coefficient correlation was 0.995 5,the limit of detection was 0.125 μg / ml,the recovery was between 85.6% and 107.1%,the variation coefficient was lower than 10%,and the reagent does not react with other samples except HSV-1 antigen.This method has a good correlation with virus titer.Conclusion: The QELISA for HSV-1 particle was successfully developed,which provide a new approach for rapid and quantitative detection of HSV-1 antigen