Selective protection of cells against X-irradiation. Isoproterenol protects only those cells that possesβ-adrenoreceptors

Summary In mixed culture of Chinese hamster fibroblatst, clone 431, and transformed murine L fibroblasts, clone B-82, isoproterenol was found to protect only 431 cells against ionizing radiation. It was shown that 431 cells, in contrast to B-82 cells, possess-adrenoreceptors, and the radioprotective effect of isoproterenol can be realized only if this agent interacts with-adrenoreceptors coupled with the cAMP system. Since malignization often causes the disappearance of-adrenergic and other hormone receptors, the combined culturing and irradiation of the cells studied can be regarded as a model of the growth of malignant cells (B-82) among normal tissue cells (431 cells) under conditions of radiation therapy. A possibility of selective protection against radiation damage of normal tissue cells, with retention of the former radiosensitivity of tumor cells, is discussed.     

虫草菌提取物对HL-60细胞的抑制作用及G2/M期阻滞的诱导

对人工培养的虫草菌菌丝体提取物进行了体外抗肿瘤活性及其作用机理的研究．依次用石油醚、乙酸乙酯、乙醇和水提取人工培养的虫草菌菌丝体，分别得到石油醚、乙酸乙酯、乙醇和水提取物．采用MTT比色法检测发现乙酸乙酯提取物显著抑制类前骨髓白血病细胞HL-60的增殖活性，半数抑制质量浓度（IC50）约为25μg／mL．并采用流式细胞术和Western blotting等方法进一步研究虫草菌乙酸乙酯提取物抑制HL-60细胞生长的作用机理．用流式细胞仪检测HL-60细胞DNA含量发现，25μg／mL虫草菌乙酸乙酯提取物作用12～2Ah后，S期细胞减少，而G2／M期细胞增多，表明细胞周期中G2／M检验点被阻滞．Western blotting分析结果表明，在虫草菌乙酸乙酯提取物作用后，HL-60细胞中G2／M检验点相关周期蛋白p34^cdc2表达量降低．     

中碳调质钢34CrNi3MoA焊接性研究

空压机的叶轮盘和叶轮盖均为34CrNi3MoA，34CrNi3MoA为中碳调质钢。焊接性差，空压机中要求在调质态下焊接，容易产生裂纹，焊接难度大，为确保焊接质量，对其焊接性进行分析、试验，找出最佳的焊接工艺．     

人WDR79基因启动子表达载体的构建及鉴定

人WDR79是一种重要的支架蛋白,在端粒酶组装、卡哈尔体(Cahar body)形成和DNA损伤修复等过程中发挥着重要作用。采用PCR扩增技术获得人WDR79基因启动子上游DNA序列,构建人WDR79基因启动子荧光素酶报告基因载体pGL3-WDR79-promoter;通过双酶切、琼脂糖凝胶电泳、DNA测序和荧光素酶活性测定等实验手段,验证质粒pGL3-WDR79-promoter构建的正确性及其表达活性。本研究结果为进一步探讨人WDR79基因表达的调控机制奠定实验基础。     

A combination of leaf rust resistance gene Lr34 and lesion mimic gene lm significantly enhances adult plant resistance to Puccinia triticina in wheat

Leaf rust caused by Puccinia triticina is an economically-important disease in wheat worldwide.A combination of different types of resistance genes may significantly enhance rust resistance under rust-favorable conditions.To investigate the interactions between the rust resistance gene Lr34 and the lesion mimic gene lm on 1BL in Ning 7840,a segregating F8-10 population of 180 recombinant inbred lines was developed from Ning 7840/Chokwang and evaluated for both lesion mimic expression and leaf rust response at the adult plant stage in a greenhouse.A major quantitative trait locus(QTL),derived from Sumai 3,was co-localized with Lr34 on chromosome 7D and explained 41.5% of phenotypic variations for rust severity and 22.1% for leaf tip necrosis(LTN).The presence of Lr34 was confirmed by Lr34-specific markers cssfr1 and cssfr2 in Ning 7840 and Sumai 3.Unlike Lr34,lm conditioned a spontaneous lesion mimic phenotype and had a significant effect on reducing uredinial size,and a smaller effect on severity.Additive effects were observed between lm and Lr34 for severity and LTN,and an epistatic effect was observed for infection type.Single marker analysis also identified several other QTL with minor effects on severity,infection type,or LTN.     

WDR34 is a novel TAK1-associated suppressor of the IL-1R/TLR3/TLR4-induced NF-κB activation pathway

Toll-like receptors (TLRs) act as sensors of microbial components and elicit innate immune responses. All TLR signaling pathways activate the nuclear factor-kappaB (NF-κB), which controls the expression of inflammatory cytokine genes. Transforming growth factor-β-activated kinase 1 (TAK1) is a serine/threonine protein kinase that is critically involved in the activation of NF-κB by tumor necrosis factor (TNFα), interleukin-1β (IL-1β) and TLR ligands. In this study, we identified a novel protein, WD40 domain repeat protein 34 (WDR34) as a TAK1-interacting protein in yeast two-hybrid screens. WDR34 interacted with TAK1, TAK1-binding protein 2 (TAB2), TAK1-binding protein 3 (TAB3) and tumor necrosis factor receptor-associated factor 6 (TRAF6) in overexpression and under physiological conditions. Overexpression of WDR34 inhibited IL-1β-, polyI:C- and lipopolysaccharide (LPS)-induced but not TNFα-induced NF-κB activation, whereas knockdown of WDR34 by a RNA-interference construct potentiated NF-κB activation by these ligands. Our findings suggest that WDR34 is a TAK1-associated inhibitor of the IL-1R/TLR3/TLR4-induced NF-κB activation pathway. D. Gao and R. Wang contributed equally to this work.     

草菇GV34菌株特性研究

GV34菌株,菌丝生长适应温度范围较广,在24～32℃温度良好生长,在23～25℃偏低温度下正常出菇,能适应气温骤降和昼夜温差大的气候环境,适宜pH为7.0～10.0;培养基含水量为65～70％;光照(400勒克司)可加速菌丝生长;能利用多种碳、氮源;产量高而稳定,棉籽皮的生物学效率为40.0～55.5％,稻草和麦秸为25％左右,是适合我国北方地区栽培的草菇优良菌株。     

重组人甲状旁腺素1-34在毕赤酵母克隆及表达的研究

人甲状旁腺素(Parathyroid hormone,PTH)是由人甲状旁腺主细胞分泌的直链肽,含84个氨基酸,是维持体内钙磷平衡的主要激素。PTH通过识别骨骼、小肠和肾脏等细胞表面特异性受体,与降钙素和维生素D共同调节Ca2+,PO43-的代谢,具有明显的成骨作用。研究发现,PTH的N-端34肽(PTH 1-34)具有完全的PTH受体结合能力与生物活性。目前PTH 1-34作为临床治疗骨质疏松症的注射剂已在美国上市,但价格昂贵且需要每天注射给药。而国内关于PTH1-34的临床研究很少,所以有必要通过基因工程手段获取PTH 1-34,降低成本并可大规模制备目的蛋白。本文概述了PTH近年来在国内外的研究情况,利用目前发展较快的毕赤酵母真核表达系统,构建了高效表达PTH 1-34毕赤酵母工程菌。为今后上发酵罐摸清条件。     

青海省东莫扎抓铅锌矿床成矿期和成矿阶段分析

通过对青海省东莫扎抓铅锌矿床的黄铁矿δ34S与方铅矿的δ34S值、矿物生成顺序及C、O同位素特征进行研究,结果表明:东莫扎抓铅锌矿床可分为海底热液喷流沉积期、热液期、火山热液叠加改造期及表生期等4个成矿期;铅锌矿成矿阶段可分为5个阶段,分别为白云石化阶段、重晶石化阶段、多金属硫化物阶段、方解石化阶段及粘土化阶段;成矿流体中的碳主要来自围岩,从成矿早期到成矿后期大气降水的参与逐步增多。在多期区域构造作用的背景下,东莫扎抓呈现多期次多阶段叠加成矿的特点。     

SAPO-34和纳米ZSM-5分子筛在甲醇转化制烯烃中的催化性能研究

合成了具有CHA结构的SAPO-34和具有MFI结构的纳米ZSM-5分子筛,采用XRD,BET,NH3-TPD,SEM等手段进行了表征,并考察了其在甲醇转化制烯烃(MTO)反应中的催化性能.结果表明:在MTO催化反应中,SAPO-34分子筛表现出很高乙烯和丙烯的选择性,而纳米ZSM-5对丙烯具有较高的选择性.同时,小晶粒纳米ZSM-5具有较长的催化荆寿命,因此具有潜在的工业化应用前景.