Mutational analysis of the proteolytic cleavage site of glycoprotein B (gB) of Marek''s disease virus

The Marek's disease virus (MDV) glycoprotein B (gB) precursor, gp100, is proteolytically cleaved into two disulfide-linked subunits, gp60 and gp49. In the gB homologs of most other herpesviruses, a tetrapeptide, Arg-Xaa-Arg-Arg, is immediately upstream from the predicted cleavage site. We have investigated the specificity of the proteolytic cleavage in gplOO by introducing mutations within its predicted cleavage site (Arg-Leu-Arg-Arg) and expressed these mutants in recombinant fowlpox virus (FPV). The results show that all three Arg residues at the predicted cleavage site play an important role in the specific proteolytic cleavage of gp100. Furthermore, we demonstrated that the cleavage of gplOO is not necessary for transport of gB to the cell surface.     

红毛五加叶的三萜皂甙

红毛五加（ＡｃａｎｔｈｏｐａｎａｘｇｉｒａｌｄｉｉＨａｒｍｓ）系五加科五加属植物,分布于河北、河南、四川、陕西、甘肃等省,有祛风湿、通关节、强筋骨、治痿痹等功效［１］。其化学成分未见报道。本文报道红毛五加叶的５个三萜皂甙（甙Ⅰ、Ⅱ、Ⅲ、Ⅳ和Ⅴ）的分离鉴定。它们均首次从该属植物发现,其结构如下：　　　　　　　　　　　　　Ｒ１　　　　　　　　　　　　　　Ｒ２　　　　　　　　Ⅰ　ｒｈａｍ－（１→２）－ａｒａ　　　　　Ｈ　　　　　　　Ⅱ　Ｈ　　　ｒｈａｍ－（１→４）－ｇｌｃ－（１→６）－ｇｌｃ　　　　　…     

河西走廊不同生态型芦苇核酸代谢季节动态研究

分布在甘肃河西走廊的４ 种生态型芦苇（Ｐｈｒａｇｍ ｉｔｅｓｃｏｍ ｍ ｕｎｉｓＴｒｉｎ．）的核酸代谢季节变化有差异。盐化草甸芦苇ＲＮＡ 含量持续增加,ＤＮＡ 含量相对稳定,其它３ 种生态型芦苇的ＲＮＡ 和ＤＮＡ 含量以５月份为最高。过渡带芦苇的ＲＮＡ 含量、沼泽芦苇及沙丘芦苇的ＤＮＡ含量９ 月份略有增高。盐化草甸芦苇与过渡带芦苇的ＤＮａｓｅ和ＲＮａｓｅ的活性７ 月份最高,沼泽芦苇与沙丘芦苇的ＤＮａｓｅ和ＲＮａｓｅ活性５—９ 月份呈增高趋势。盐化草甸芦苇的ＤＮＡ 和ＲＮＡ 合成活性不断升高,过渡带芦苇和沼泽芦苇的ＤＮＡ 和ＲＮＡ 合成活性及沙丘芦苇的ＲＮＡ 合成活性５—９月份均降低,仅沙丘芦苇的ＤＮＡ合成活性增强。ＲＮＡ 聚丙烯酰胺梯度凝胶电泳分析结果表明,４ 种生态型芦苇均含有２５Ｓ、２３Ｓ、１８Ｓ、１６Ｓ大分子量ｒＲＮＡ 和小分子量５．８Ｓ、５Ｓ、４．５ＳｒＲＮＡ 及４ＳｔＲＮＡ。大分子量ＲＮＡ 的含量高于小分子量ＲＮＡ 含量。不同生态型及同一生态型芦苇的不同发育时期,相同的ＲＮＡ 组分含量各不相同。且发育过程中２３Ｓ、１８Ｓ、１６ＳｒＲＮＡ 在不同月份发生不同程度的降解。由此,我们认为,核酸代谢的差异性是４ 种生态型由生长转入衰     

质体醌重组的D1／D2／Cytb559复合物的荧光衰减动力学和光破坏作用

光系统Ⅱ反应中心Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 在分离纯化过程中失去了电子受体ＱＡ 和ＱＢ,人工合成的质体醌可以与Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 复合物发生重组。癸基质体醌（ＤＰＱ）与Ｄ１／Ｄ２／Ｃｙｔｂ５９９ 复合物的重组导致该复合物的荧光强度下降及发射光谱蓝移,同时两个与光化学活性相关的长寿命（２４ ｎｓ和７３ ｎｓ）荧光衰减组分占整个荧光的百分数下降,这些结果表明ＤＰＱ作为Ｐｈｅｏ－ 的电子受体,限制了Ｐ６８０＋ ·Ｐｈｅｏ－ 的电荷重组。ＤＰＱ 的加入对Ｄ１／Ｄ２／Ｃｙｔｂ５５９复合物中Ｃｈｌａ 分子的光破坏敏感性影响不大,但β－胡萝卜素在加入ＤＰＱ 之后可以被光照破坏,这个过程可能与β－胡萝卜素的生理功能相关。     

三褶脉紫菀中的新二萜甙

三褶脉紫菀（ＡｓｔｅｒａｇｅｒａｔｏｉｄｅｓＴｕｒｃｚ．）系菊科多年生草本植物,遍布全国,是民间常用的中药,有清热解毒、祛痰镇咳的功效［１,２］。化学工作者们曾从其同属植物紫菀（ＡｓｔｅｒｔａｒａｒｉｃｕｓＬ．ｆ．）中分离到紫菀酮（ｓｈｉｏｎｏｎｅ）、槲皮素（ｑｕｅｒｃｅｔｉｎ）、无羁萜（ｆｒｉｅｄｅｌｉｎ）、表无羁萜（ｅｐｉｆｒｉｅｄｅｌｉｎｅｌ）、毛叶醇（ｌａｃｈｎｏｐｈｙｌｌｏｌ）、乙酸毛叶酯（ｌａｃｈｎｏｐｈｙｌｌｏｌａｃｅｔａｔｅ）、茴香醚（ａｎｅｔｈｏｌｅ）以及紫菀三萜皂甙［２—４］…     

田麻属的分类学研究

本文对田麻属植物的分类进行了研究,确认1种2变种,归并了1种3变种1变型,降级1种。     

Localization of a New Type of X-Linked Liver Glycogenosis to the Chromosomal Region Xp22 Containing the Liver α-Subunit of Phosphorylase Kinase (PHKA2)

We describe here a new type of X-linked liver glycogen storage disease. The main symptoms include liver enlargement and growth retardation. The clinical and biochemical abnormalities of this glycogenosis are similar to those of classical X-linked liver glycogenosis due to phosphorylase kinase deficiency (XLG). However, in contrast to patients with XLG, the patients described here have no reduced phosphorylase kinase activity in erythrocytes and leukocytes, and no enzyme deficiency could be found. Linkage analysis of four families with this X-linked type of liver glycogenosis assigned the disease gene to Xp22. Lod scores obtained with the markers DXS987, DXS207, and DXS999 were 3.97, 2.71, and 2.40, respectively, all at 0% recombination. Multipoint linkage analysis localized the disease gene between DXS143 and DXS989 with a maximum lod score of 4.70 at θ = 0, relative to DXS987. As both the classical XLG gene and the liver α-subunit of PHK (PHKA2) are also located in Xp22, this variant type of XLG may be allelic to classical XLG, and both diseases may be caused by mutations in PHKA2. Therefore, we propose to classify XLG as XLG type I (the classical type of XLG) and XLG type II (the variant type of XLG).     

Cell-substrate adhesion and metastatic potential of cultured mesothelioma cells induced by asbestos

Cell-substrate adhesion was quantified for two cultured mesothelioma cell lines (epitheliomatus and sarcomatous) on glass, fibronectin and laminin substrates. Interference reflection microscopy (IRM) was used to image the adhesion patterns of cells and a grey level analysis was employed to quantify adhesion. Sarcomatous cells demonstrated marked adhesion to glass and fibronectin-coated substrates but not to laminin-coated substrate, with the greatest adhesion occurring on the fibronectin-coated surface. This adhesion was accompanied by cytoplasmic spreading. By contrast, epitheliomatous cells showed little tendency to adhere to any of the substrates and only showed significant spreading when in contact with the laminin substrate (P < 0.01). A bioassay was used to determine the metastatic potential of each of the cell lines. Via the intravenous route, the sarcomatous cells killed the host rats in 24.7 ± 1.5 (S.D.) days compared to 27.3 ± 0.9 (S.D.) days for the epitheliomatous cells (P < 0.01). After subcutaneous inoculation of tumour cells, the sarcomatous cells killed the host rats in 54.7 ± 0.7 (S.D.) days compared to 48.5 ± 0.5 (S.D.) days for the epitheliomatous cells (P < 0.01). We conclude that the results of the metastasis bioassays were consistent with the predicted behavior of these cell lines based on their ability to adhere to substrates in the in vitro adhesion assays.     

人脑髓鞘碱性蛋白cDNA体外扩增、克隆和鉴定

采用聚合酶链反应(PCR)从人脑cDNA文库中扩增出600bp的髓鞘碱性蛋白(MBP)cDNA片段,与载体pGEM-3Zf(+)平端连接.重组质粒DNA转化宿主菌JM109,在含X-gal和IPTG的平板上直接筛选阳性克隆.限制性内切酶分析和成套引物扩增鉴定证明,该克隆含有7个外显子的21.5kD人脑MBP全长编码序列.     

人重组IL6／IL2融合蛋白的变性、复性及纯化

经超声破碎,分离已表达CH925包涵体,较系统地研究变性剂浓度、融合蛋白浓度对蛋白折叠的影响.在还原型及氧化型谷胱甘肽复性条件下,成功地将融合蛋白CH925折叠成具有IL6及IL2双活性蛋白,IL6的比活为2.3×10⁸U/mg, IL2比活为2.2×10⁶U/mg.经阴离子交换、凝胶过滤层析,获得一定纯度的CH925,配合反相HPLC.洗脱收集蛋白峰,CH925纯度为98%.