热处理工艺对C46500黄铜脱锌腐蚀性能的影响

研究了热处理工艺对C46500黄铜显微组织及其抗脱锌腐蚀性能的影响.结果表明：C46500黄铜挤压坯为α+β两相组织,经高温退火处理后,组织中β相向α相转变,在480℃时,固溶度达到极值,且β相由网状结构向等轴状转变;C46500黄铜经480℃+6 h退火处理后,具有良好的抗脱锌腐蚀性能.     

鼠妇富含蛋白多肽提取物的镇痛作用研究

采用蛋白酶法与酸碱法提取鼠妇蛋白多肽成分,利用化学刺激和热刺激法观察提取物对小鼠的镇痛作用,同时测定小鼠脑组织中的去甲肾上腺素(NE),多巴胺(DA)和5-羟色胺(5-HT)水平.以蛋白多肽中氨基酸种类,尤其是兴奋性氨基酸天门冬氨酸和谷氨酸,抑制性氨基酸甘氨酸和γ-氨基丁酸的质量分数为指标,醋酸扭体次数抑制率和热板实验痛阈值为镇痛活性指标,对两种提取方法进行比较并且初步研究镇痛作用机理,结果表明酸碱法制备的富含蛋白多肽的鼠妇提取物镇痛效果优于酶法,该提取物能明显提高小鼠醋酸扭体次数抑制率与热板实验痛阈值,且能明显提高小鼠脑内NE,DA和5-HT质量分数水平.酸碱法提取蛋白多肽对小鼠具有明显的镇痛作用,其镇痛作用可能与脑内的单胺递质类5-HT有关.     

星海链霉菌卤化酶重组蛋白在大肠杆菌中可溶表达

大肠杆菌(Escherichia coli,E.coli)是表达异源蛋白的良好宿主,但常遇到蛋白表达产物不可溶的困难.在对来自星海链霉菌的卤化酶基因sinH进行大肠杆菌异源表达时,为克服蛋白表达产物可溶性低的问题,探讨了不同载体对蛋白可溶表达的影响.利用pET28a进行SinH表达时不能得到可溶的目标蛋白;使用含有泛素标签及内含肽的载体pHUIE实现了卤化酶蛋白SinH的可溶表达,但纯化后纯度不高;利用带有链霉菌分子伴侣蛋白基因的载体pET28a-SinH与pETcoco-pL1SL2在E.coli BL21(DE3)中共表达,在30℃,0.1mmol/L IPTG诱导条件下表达4h,成功获得大量可溶蛋白,使用亲和层析(Ni-NTA)纯化,获得了较纯的目标蛋白SinH,上述研究结果为在大肠杆菌中进行其他链霉菌蛋白的可溶表达提供了参考.     

重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白生物仿制药对大鼠类风湿性关节炎的治疗作用

目的:评价重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白(TNFR-Fc)生物仿制药对大鼠佐剂性关节炎的治疗作用.方法:将大鼠随机分成6组:阴性对照组(生理盐水)、阳性药物组(Enbrel)和TNFR-Fc高、中、低质量分数组,空白组(无炎症),每组6只,弗氏完全佐剂(CFA)建立类风湿性关节炎模型.给药13 d后,分别测量大鼠体重、后足足垫厚度,关节炎指数评分,ELISA法测量细胞因子水平.结果:与阴性对照组相比,Enbrel组和TNFR-Fc大、中、小质量分数组的大鼠体质量明显增加(P0.05)、继发性足肿胀减弱(P0.05)、关节炎评分分值、IL-1β、TNF-α、IL-6含量均减小(P0.05),IL-10含量升高(P0.05).结论:TNFR-Fc通过降低炎性细胞因子IL-1β、IL-6、TNF-α水平以及升高IL-10水平来发挥治疗类风湿性关节炎的作用.     

pH和DO作为A2N-IC-SBR工艺实时控制参数

试验从硝化污泥和聚磷污泥的培养开始至A2N-IC-SBR工艺稳定运行结束,系统地记录了污泥驯化培养阶段、A2N工艺运行阶段、A2N-IC工艺运行阶段中pH和DO的变化与氮磷浓度的关系.结果表明:厌氧阶段pH的变化比较复杂,与进水碳磷比、反硝化聚磷菌和好氧聚磷菌的富集程度等因素有关,不同的进水水质与污泥有不同的变化规律;诱导结晶阶段pH的变化受到钙盐投药方式以及混合方式的影响,pH与SP浓度的变化并不存在明显的相关性;硝化反应中硝化作用完成的特征点较明显,d(DO)/dt最大值点及d(pH)/dt由负变正的特征点均可作为硝化完成的指示点;好氧聚磷阶段,聚磷终点与pH拐点、DO大幅上升出现的时刻相同;缺氧聚磷阶段,pH停止上升的时刻可以用来指示聚磷的完成.     

共表达KnobS蛋白与LTB蛋白的重组干酪乳杆菌构建

在干酪乳杆菌中表达减蛋综合征病毒纤维蛋白KnobS,并分析其抗原性。分别将编码减蛋综合征病毒主要免疫保护性抗原纤维蛋白KnobS与大肠杆菌不耐热肠毒素B亚单位(LTB)基因插入干酪乳酸杆菌分泌表达载体pMG36e-UP/L中,成功构建重组表达载体pMG36e-UP/LTB-KnobS,获得表达融合蛋白KnobS-LTB的重组乳酸菌干酪乳杆菌表达系统;经SDS-PAGE和Western-blot检测表明,有大小约41kD的蛋白表达,具有与天然病毒蛋白一样的抗原特异性。在干酪乳杆菌中成功地表达了含减蛋综合征病毒抗原的融合蛋白KnobS-LTB,且具有较好的抗原性,为减蛋综合征病毒重组乳酸菌活菌口服疫苗的研制奠定重要的物质基础。     

基于基因组的TEV蛋白酶的高表达

TEV蛋白酶由于其高酶切活性、酶切位点的专一性和酶切条件的宽容性而在蛋白分离和蛋白质组学研究等领域有着广泛的应用.目前获得TEV蛋白酶的方法是将克隆在质粒上的TEV基因在大肠杆菌表达菌株BL21(DE3)中实现过表达.但本方法有一定缺点,如需使用抗生素,这就可能在后续的纯化中引入杂质,菌株群体中不均一性而降低产量等.本研究通过重组工程方法将受T7强启动子驱动的,与麦芽糖结合蛋白MBP融合的TEV蛋白酶基因整合至BL21(DE3)的基因组上进行过表达.MBP-TEV在细胞内自剪切获得分离的TEV.NiNTA亲和层析得到纯化的TEV,产量可达4.2 mg/L.所分离的TEV表达出良好的酶切活性.本菌株有着以之大规模获得TEV的潜力,所建立的通过重组工程将外源基因整合至BL21(DE3)基因组的进行表达的方法也可成为通用的平台技术.     

Finite element models and molecular dynamic simulations for studying the response of mast cell under mechanical activation

In micropipette aspiration experiment, increasing mechanical stress applied to cell membrane induced degranulation of mast cell as well as a current that could be inhibited by an inhibitor, which is specific for the transient receptor potential vanilloid （TRPVs） channels. To determine the sensitivity of TRPVs to membrane strain and tension, and to gain new insights into the activation mechanism of TRPVs, finite element models of mast cell and molecular dynamic simulations of human aquaporin-1 are presented. During the finite element simulations, the cell membrane sustained to micropipette aspiration was simulated, and the strain distribution along membrane thickness direction was obtained. Besides, combining the finite element models of osteoblast aspirated into micro- pipette and other compared models, we examined the relationship between cell mechanical stimulations and mechanical attributes and presented a new perspective to determine the cell equivalent elastic modulus. Consid- ering the indetermination of TRPV crystal structure, human aquaporin-1, one kind of the channel membrane proteins, substituting for TRPV, has been studied with molecular dynamic （MD） simulations, under different external lateral tensions which have been obtained in mast cell finite ele- ment simulations, to investigate the mechanical stimulation effects on the membrane channels. The simulations show that human aquaporin-1 undergoes significant conforma- tional change and expands in accordance with lateraltension, which not only confirms the tendency of the pre- vious electrophysiological experiments but also leads us to a better understanding of TRPVs. The multi-scale study combining finite element simulation and MD simulation is a significant breakthrough in the field of mechanical mechanism in cell system.     

Advances in research on Shadoo,shadow of prion protein

Prion plays a central role in the pathogenesis of transmissible spongiform encephalopathies, also known as prion diseases. However, the biology of the protein and the pathophysiology of these diseases remain largely unknown. It has been speculated that additional factor or factors may be involved in the pathogenesis of prion diseases. Recently, a PrP-like protein, recognized as shadow of prion protein （Shadoo, Sho）, is thought to be an interesting candidate factor because both the prion protein and Sho have been shown to have overlapping expression patterns and shared functions. Therefore, extensive study of Sho may advance our understanding of the enigmatical biology of prion and prion diseases. In this review, recent studies on Sho asso- ciated with prion diseases and functions are summarized. These studies have demonstrated the functional importance of Sho, and they further need to investigate its biological roles in prion diseases.     

不同微环境有机蒙脱土的制备及吸附亚甲基蓝的研究

合成了一系列带不同官能团的表面活性剂并用其修饰蒙脱土(MMT).通过X射线衍射(XRD)和热重分析(TG)对所修饰的蒙脱土进行了表征,结果表明:成功地制备出了3种不同微环境的有机蒙脱土:胺基有机蒙脱土(MMT-12-N(CH3)2)、羟基有机蒙脱土(MMT-12-OH)和甲基有机蒙脱土(MMT-12-CH3).研究比较了溶液pH、接触时间和染料浓度对3种不同微环境的有机蒙脱土吸附亚甲基蓝(MB)的影响.结果表明:MMT-12-CH3的吸附量大且受pH影响最小,MMT-12-N(CH3)2和MMT-12-OH分别在5-9和5-8的pH范围也都有较好的吸附效果,吸附MB的动力学曲线都遵从假二级动力学模型,吸附等温线符合Langmuir模型,相同条件下,其吸附量大小依次为MMT-12-CH3MMT-12-OHMMT-12-N(CH3)2.