去势对离体大鼠心脏缺血/再灌注心功能及心肌凋亡的影响

目的:观察去势对离体大鼠心脏缺血／再灌注心脏功能和心肌凋亡的影响。方法:SD大鼠28只,随机分为去势组、对照组,每组14只。制备大鼠离体缺血／再灌注模型(缺血30min,再灌注2h),观察左室压力,再灌注结束后检测心肌梗死率和细胞凋亡指数,免疫组化技术检测心肌组织的Bcl-2、Bax水平。结果:(1)与对照组相比,去势组再灌注后的心脏左室收缩及舒张功能无显著变化(P>0．05);(2)去势组心肌梗死范围(43．68±6．89％)较对照组(39．33±7．85％)增加,但无统计学差异;(3)对照组和去势组间心肌细胞凋亡指数无统计学差异(P>0．05),心肌组织中Bcl-2、Bax含量未见显著变化。结论:去势对心脏缺血／再灌注心脏功能没有保护作用,而且不影响心肌细胞凋亡过程,生理剂量的雄激素对缺血再灌注后的心脏功能不产生损害作用。     

用高效液相层析进行TSH-β亚单位的分离

 本文在分离纯化TSH的基础上,用高效液相排阻层析的方法成功地将THS—β亚单位与TSH—α亚单位分离开。分离的TSH—β亚单位、TSH—α亚单位与LH—α亚单位分别重组后,TSH活性得到了很好的恢复。用这种方法分离TSH—β亚单位时间短、操作简单,分离效果好,重复性好。     

Defect‐Rich Soft Carbon Porous Nanosheets for Fast and High‐Capacity Sodium‐Ion Storage

Soft carbon has attracted tremendous attention as an anode in rocking‐chair batteries owing to its exceptional properties including low‐cost, tunable interlayer distance, and favorable electronic conductivity. However, it fails to exhibit decent performance for sodium‐ion storage owing to difficulties in the formation of sodium intercalation compounds. Here, microporous soft carbon nanosheets are developed via a microwave induced exfoliation strategy from a conventional soft carbon compound obtained by pyrolysis of 3,4,9,10‐perylene tetracarboxylic dianhydride. The micropores and defects at the edges synergistically leads to enhanced kinetics and extra sodium‐ion storage sites, which contribute to the capacity increase from 134 to 232 mAh g^?1 and a superior rate capability of 103 mAh g^?1 at 1000 mA g^?1 for sodium‐ion storage. In addition, the capacitance‐dominated sodium‐ion storage mechanism is identified through the kinetics analysis. The in situ X‐ray diffraction analyses are used to reveal that sodium ions intercalate into graphitic layers for the first time. Furthermore, the as‐prepared nanosheets can also function as an outstanding anode for potassium‐ion storage (reversible capacity of 291 mAh g^?1) and dual‐ion full cell (cell‐level capacity of 61 mAh g^?1 and average working voltage of 4.2 V). These properties represent the potential of soft carbon for achieving high‐energy, high‐rate, and low‐cost energy storage systems.     

Agrobacterium tumefaciens mediated transient expression of plant cell wall‐degrading enzymes in detached sunflower leaves

For biofuel applications, synthetic endoglucanase E1 and xylanase (Xyn10A) derived from Acidothermus cellulolyticus were transiently expressed in detached whole sunflower (Helianthus annuus L.) leaves using vacuum infiltration. Three different expression systems were tested, including the constitutive CaMV 35S‐driven, CMVar (Cucumber mosaic virus advanced replicating), and TRBO (Tobacco mosaic virus RNA‐Based Overexpression Vector) systems. For 6‐day leaf incubations, codon‐optimized E1 and xylanase driven by the CaMV 35S promoter were successfully expressed in sunflower leaves. The two viral expression vectors, CMVar and TRBO, were not successful although we found high expression in Nicotiana benthamiana leaves previously for other recombinant proteins. To further enhance transient expression, we demonstrated two novel methods: using the plant hormone methyl jasmonic acid in the agroinfiltration buffer and two‐phase optimization of the leaf incubation temperature. When methyl jasmonic acid was added to Agrobacterium tumefaciens cell suspensions and infiltrated into plant leaves, the functional enzyme production increased 4.6‐fold. Production also increased up to 4.2‐fold when the leaf incubation temperature was elevated above the typical temperature, 20°C, to 30°C in the late incubation phase, presumably due to enhanced rate of protein synthesis in plant cells. Finally, we demonstrated co‐expression of E1 and xylanase in detached sunflower leaves. To our knowledge, this is the first report of (co)expression of heterologous plant cell wall‐degrading enzymes in sunflower. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:905–915, 2014     

Solution Structure of Ectodomains of the Insulin Receptor Family: The Ectodomain of the Type 1 Insulin-Like Growth Factor Receptor Displays Asymmetry of Ligand Binding Accompanied by Limited Conformational Change

The insulin receptor (IR) and the homologous Type 1 insulin-like growth factor receptor (IGF-1R) are cell-surface tyrosine kinase receptors that effect signaling within the respective pathways of glucose metabolism and normal human growth. While ligand binding to these receptors is assumed to result in a structural transition within the receptor ectodomain that then effects signal transduction across the cell membrane, little is known about the molecular detail of these events. Presented here are small-angle X-ray scattering data obtained from the IR and IGF-1R ectodomains in solution. We show that, in solution, the ectodomains of IR and IGF-1R have a domain disposition that is very similar to that seen in the crystal structure of the ectodomain of IR, despite the constituent domains being in relatively sparse contact and potentially mobile. We also show that the IGF-1R ectodomain is capable of binding up to three molecules of IGF-1 in solution, with surprisingly little apparent change in relative domain disposition compared to the apo form. While the observed 3:1 ligand-binding stoichiometry appears to contradict earlier explanations of the absence of a bell-shaped dose-response curve for IGF-1R in ligand displacement assays, it is readily understood in the context of the harmonic oscillator model of the negative cooperativity of ligand binding to IGF-1R. Taken together, our findings suggest that the structural movements within these receptors upon ligand binding are small and are possibly limited to local rotation of domains.     

Mcm10 plays an essential role in origin DNA unwinding after loading of the CMG components

The CMG complex composed of Mcm2-7, Cdc45 and GINS is postulated to be the eukaryotic replicative DNA helicase, whose activation requires sequential recruitment of replication proteins onto Mcm2-7. Current models suggest that Mcm10 is involved in assembly of the CMG complex, and in tethering of DNA polymerase α at replication forks. Here, we report that Mcm10 is required for origin DNA unwinding after association of the CMG components with replication origins in fission yeast. A combination of promoter shut-off and the auxin-inducible protein degradation (off-aid) system efficiently depleted cellular Mcm10 to <0.5% of the wild-type level. Depletion of Mcm10 did not affect origin loading of Mcm2-7, Cdc45 or GINS, but impaired recruitment of RPA and DNA polymerases. Mutations in a conserved zinc finger of Mcm10 abolished RPA loading after recruitment of Mcm10. These results show that Mcm10, together with the CMG components, plays a novel essential role in origin DNA unwinding through its zinc-finger function.     

κ-阿片受体激动通过激活KATP通道对大鼠腹主动脉产生舒张作用

为观察U50,488H（选择性κ－阿片受体激动剂）对大鼠腹主动态的佶张作用,并探讨其机制,实验采用离体血管灌流实验,测定血管张力的改变。结果显示：（1）U50,488H对大鼠腹主动脉具有明显的舒张作用;（2）U50,488H对大鼠腹主动脉的舒张效应部分依赖于内皮细胞的存在;（3）优降糖和格列甲嗪可明显抑制U50,488H对大鼠腹主动脉的佶张作用;（4）U50,488H的舒张血管效应与M受体、β受体、前列腺素及NO无关。结果表明,U50,488H是一种有效的扩血管物质,其舒张血管的效应具有内皮依赖性,且与KATP通道有密切关系。     

抗人类免疫缺陷病毒1型广谱中和抗体的研究进展

现行抗反转录病毒治疗药物的联合应用可有效抑制艾滋病进程并显著延长患者寿命,但由于人类免疫缺陷病毒1型(human immunodeficiency virus type 1,HIV-1)潜伏库的存在,艾滋病迄今尚无法治愈。近年发现抗HIV广谱中和抗体能有效降低患者体内病毒载量并延缓疾病进程,为研发艾滋病疫苗和治愈策略带来了曙光,尤其是序贯免疫策略的使用极大推进了广谱中和抗体的开发和应用进程。2018年,美国食品药品管理局(Food and Drug Administration,FDA)批准了第1个临床应用的广谱中性单克隆和抗体,无疑为抗HIV单克隆抗体药物的研发注入了一支强心剂。本文围绕近年来抗HIV广谱中和抗体的研究进展进行综述,探讨未来广谱中和抗体研发面临的挑战。     

乙型肝炎表面抗原亚型“y”决定簇抗原性研究

用免疫扩散法(ID)对新疆、内蒙、西藏三地区的维吾尔族、蒙古族及藏族37份ayw/HBsAg阳性标本进行分型,36份为ayw2亚型,1份ayw4亚型,后者为我国ayw2优势亚型区首次发现的另一种新亚型,用y单克隆抗体酶标电泳法对ayw1、ayw2、ayw3和ayw4进行了抗原性研究,结果证明,ayw2和ayw4与ayw1和ayw3两组中的y为两种抗原性不完全相同的决定簇,本研究结果对乙型肝炎流行病学调查和乙肝疫苗抗原的合理组成有一定参考价值。