哺乳动物透明带糖蛋白及其生物活性

透明带在哺乳动物的受精过程中发挥着重要作用,透明带化学成分及其生物活性的研究对于了解精卵识别、顶体反应的诱导等过程的分子机理具有重要意义．近10年来的研究表明透明带主要由糖蛋白（ZPGPs）组成,是在细胞质内合成后转移至透明带的.大多数动物的ZPGPs为4～5种,不同种类动物的ZPGPs的氨基酸序列存在高度同源性.在受精过程中,ZPGPs具有精子受体和诱导顶体反应的双重作用,ZPGPs含有N－连接和O－连接寡聚糖,这些寡糖链是ZPGPs行使生物活性不可缺少的部分．     

Morphometric Analysis of Hepatocellular carcinoma

Ｍｏｒｐｈｏｍｅｔｒｉｃ　Ａｎａｌｙｓｉｓ　ｏｆ　Ｈｅｐａｔｏｃｅｌｌｕｌａｒ　ｃａｒｃｉｎｏｍａＬａｉＭａｏ－ｄｅ（来茂德）;ＣｈｅｎＰｅｉ－ｈｕｉ（陈培辉）ａｎｄＺｈｏｕＳｈｕｉ－ｙｕｎ（周水云）（ＤｅｐａｒｔｍｅｎｔｏｆＰａｔｈｏｌｏｇｙ,Ｚｈ...     

LDL受体基因cDNA的RT－PCR分离、克隆及其在RFLP中的应用

利用ＲＴ－ＰＣＲ技术分离低密度脂蛋白受体基因ｃＤＮＡ,将长为２６０５ｂｐ的ｃＤＮＡ插入质粒ｐＪＮ６,并经全序列测定证实,该序列与已报道序列相比,存在两个变异碱基,即第７５４位Ｃ→Ｔ,和１６５４位的Ｇ→Ａ,这两个变异碱基并不改变编码的氨基酸,利用ＬＤＬ受体基因ｃＤＮＡ中的ＣｌａⅠ片段作为探针,检测到ＬＤＬ受体基因上外显子８的ＳｔｕⅠ位点是个限制性片段长度多态性位点。所克隆的ｃＤＮＡ含有可译框架的全部密码,因此可作为基因表达材料。     

油麻藤凝集素的荧光光谱研究

用化学修饰、内源荧光和荧光淬灭等方法研究了油麻藤凝集素（ＭＳＬ）的溶液构象变化和微环境的构象特征。研究发现ＭＳＬ分子中总共有９个色氨酸（Ｔｒｐ）残基,它们的荧光能被丙烯酰胺淬灭,但不易为ＫＩ接近而淬灭,ＭＳＬ经Ｎ－溴代琥珀酰亚胺（ＮＢＳ）修饰后,其内源性荧光发射谱发生相应变化,结果表明ＭＳＬ分子中部分Ｔｒｐ残基埋藏于分子内部,而位于分子表面的Ｔｒｐ残基可能处于分子的疏水袋中。     

木瓜蛋白酶PPAⅢ自水解作用

木瓜蛋白酶ＰＰＡⅢ自水解作用王秀艳,周慧,葛玉斌,李惟（吉林大学分子生物学系,长春１３００２３）ＰＰＡⅢ、ｐａｐａｉｎ、ｐｅｐｓｉｎｅ、ｓｔｅｍｂｒｏｍｅｌａｉｎ等都属于以Ｃｙｓ－ＳＨ为活性中心的酶,同种分子之间存在着一种相互切割的趋势,称为酶自水解...     

黄精凝集素Ⅱ分子稳定性与生物学活性研究

黄精凝集素Ⅱ分子稳定性与生物学活性研究鲍锦库,曾仲奎,周红（四川大学生物系,成都,６１００６４）本文在黄精凝集素Ⅱ纯化及性质研究的基础上,应用多种变性条件,研究其分子特性,同时对分子的巯基和色氨酸进行修饰,研究该凝集素分子保持其生物学活性与这些基团的...     

POPULATION SEASONALITY AND LARVAL DEVELOPMENT OF LAGRIA HIRTA L. (COLEOPTERA: LAGRIIDAE)*

Abstract The seasonality of the field population of Lagria hirta L. is remarkable: adults occur only from the end of June to the beginning of August, whereas larvae exist in the whole year except June. Based on the data of field observations and larval head-width measuring, the author demonstrated that L. hirta would reproduce in a very short interval in June to August; eggs hatch and develop (molt) into the 3rd, 4th or 5th (sometimes 6th) instar before winter; after larval overwintering, the beetles complete the larval development after total 8–10 times of molts and pupate in June. The larval development rate is decreased but not completely stopped during winter (the nonparametric median test, P<0. 01). This result changes the hitherto opinion of 4 or 5-instar larval development of L. hirta and will stimulate the studies on its life history.     

Identification of a 175 kDa protein as the ligand-binding subunit of the rat liver sinusoidal endothelial cell hyaluronan receptor

The rat liver sinusoidal endothelial cell (LEC) hyaluronan (HA)receptor was previously identified using a photoaffinity HAderivative (J. BioL Chem., 267, 20451–20456, 1992). Twopolypeptides with M_r = 175,000 and 166,000, were consistentlycrosslinked, suggesting that the LEC HA receptor is an oligomer.Whether one or both subunits participate in HA binding, wasnot determined. Here we investigate the HA-subunit interactionsand the potential oligomeric nature of the LEC HA receptor.When Sephacryl-400 gel filtration chromatography was used toenrich the HA receptor, the 175 kDa polypeptide was the majorband seen by SDS-PAGE analysis. Little staining was seen at166 kDa, suggesting that the 175 kDa protein could be separatedfrom the 166 kDa protein and still retain HA-binding activity.A ligand blot assay was used to determine if each individualsubunit could bind HA. LEC proteins were separated by nonreducingSDS-PAGE, and then immobilized onto nitrocellulose. ¹²⁵I-HAbound to a 175 kDa polypeptide but not to the 166 kDa protein.A high molecular weight band of     

The role of context on alpha-helix stabilization: host-guest analysis in a mixed background peptide model.

The helix content of a series of peptides containing single substitutions of the 20 natural amino acids in a new designed host sequence, succinyl-YSEEEEKAKKAXAEEAEKKKK-NH2, has been determined using CD spectroscopy. This host is related to one previously studied, in which triple amino acid substitutions were introduced into a background of Glu-Lys blocks completely lacking alanine. The resulting free energies show that only Ala and Glu- prove to be helix stabilizing, while all other side chains are neutral or destabilizing. This agrees with results from studies of alanine-rich peptide modela, but not the previous Glu-Lys block oligomers in which Leu and Met also stabilize helix. The helix propensity scale derived from the previous block oligomers correlated well with the frequencies of occurrence of different side chains in helical sequences of proteins, whereas the values from the present series do not. The role of context in determining scales of helix propensity values is discussed, and the ability of algorithms designed to predict helix structure from sequence is compared.