王瓜根抗癌糖蛋白的生理生化特征及其对肺腺癌细胞杀伤作用初步研究

经电泳分析,王瓜根活性蛋白可分为两种:其一是酸性蛋白,具细胞毒作用,等电点测定 P~I 为3.2,PAGE 电泳测定分子量为6.76×10~4道尔顿;其二是碱性蛋白,等电点为9.3,PAGE 电泳测定分子量为1.58×10~4道尔顿;微具细胞毒作用。王瓜根活性蛋白属糖蛋白,经纸层析和薄层硅胶 H 层析证实含半乳糖和木糖。扫描电镜观察和光镜连续观察,显示酸性蛋白对肺腺癌细胞的体外培齐有杀伤作用,当培养液含120μg/ml 时杀伤率达58%,对正常肺细胞作用弱;碱性蛋白对肺腺癌细胞杀伤作用较差,在同样剂量时只有47.6%杀伤率。新鲜王瓜根原汁有很强的杀伤肺腺癌细胞作用,剂量在26g/ml 时,杀伤率达60%;当提高到105g/ml 时,杀伤率达74%。试验结果提示:王瓜根活性抗癌物质,除指三萜—葫芦素之外,可能还存在另一种活性物质。这种活性抗癌物质对肺腺癌细胞表面微绒毛无作用,经处理24小时后,癌细胞开始变形,表现为不同程度内陷,32小时癌细胞膜开始溶解,48小时癌细胞溶成团块。     

Myelin sheaths: glycoproteins involved in their formation,maintenance and degeneration

Myelin sheaths are formed around axons by extending, biochemically modifying and spiraling plasma membranes of Schwann cells in the peripheral nervous system (PNS) and oligodendrocytes in the central nervous system (CNS). Because glycoproteins are prominent components of plasma membranes, it is not surprising that they have important roles in the formation, maintenance and degeneration of myelin sheaths. The emphasis in this review is on four integral membrane glycoproteins. Two of them, protein zero (P0) and peripheral myelin protein-22 (PMP-22), are components of compact PNS myelin. The other two are preferentially localized in membranes of sheaths that are distinct from compact myelin. One is the myelin-associated glycoprotein, which is localized at the inside of sheaths where it functions in glia-axon interactions in both the PNS and CNS. The other is the myelin-oligodendrocyte glycoprotein, which is preferentially localized on the outside of CNS myelin sheaths and appears to be an important target antigen in autoimmune demyelinating diseases such as multiple sclerosis. Received 8 April 2002; received after revision 13 May 2002; accepted 22 May 2002     

Blocking of lectin-like adhesion molecules on pulmonary cells inhibits lung sarcoma L-1 colonization in BALB/c-mice

Summary Adhesion and inhibition experiments with pulmonary cells of BALB/c-mouse origin and syngeneic sarcoma L-1 cells indicated that L-fucose specific lectin-like adhesion molecules, presumably situated on pulmonary cell surfaces are (at least partly) responsible for the specificity of this cell-cell interaction. Addition of specific sugars and glycoconjugates (L-fucose and fucoidan, respectively) to the incubation medium evidently inhibited the adhesion process as quantified using radiolabelled tumor cells. Unspecific carbohydrates (e.g. D-galactose) did not affect the cellular interaction. In vivo, repeated administration of fucoidan (but not of unspecific glycoconjugates) significantly inhibited the settling of metastatic sarcoma L-1 cells in the lungs of BALB/c-mice. Therefore, when lectin-like adhesion molecules on pulmonary cells were blocked with competitive glycoconjugates, tumor cell colonization of the lung could be significantly inhibited.     

水溶液中人胆汁糖蛋白与碳酸钙的结合研究

利用付里叶变换红外光谱 (FT -IR) ,结合减法、二阶导、退卷积和曲线拟合等先进光谱技术及ICP -AES分析方法 ,对人胆汁中提取的糖蛋白 (HBG)和碳酸钙 (CaCO3)反应后的滤液进行了研究。结果表明 ,HBG和碳酸钙之间存在着络合配位和多形式的氢键作用 ,使两者的微观结构发生了变化 ,形成了水溶性的HBG -碳酸钙复合物。该复合物的形成是生物矿化的基础。     

The specificity of binding of glycoprotein hormones to their receptors

The glycoprotein hormone receptor family is peculiar because, in contrast to other G protein-coupled receptors, a large N-terminal extracellular ectodomain is responsible for hormone recognition. Hormone-receptor pairs have evolved in such a manner that a limited number of positions both at the 'seat-belt' domain of the hormone and the leucine-rich repeats of the receptor, play attractive and repulsive interactions for binding and specificity, respectively. Surprisingly, the constitutive activity of the receptor, mostly modulated by highly conserved amino acids within the heptahelical domain of the receptor (i.e., outside the hormone binding region), also regulates effectiveness of hormone recognition by the extracellular part. In this review we analyze, at the molecular level, these important discriminating determinants for selective binding of glycoprotein hormones to their receptors, as well as natural mutations, observed in patients with gestational hyperthyroidism or ovarian hyperstimulation syndrome, that modify the selectivity of binding.     

禾黑芽枝霉诱变体果胶酶的分离纯化和理化特性

通过淀粉变性处理，超过滤及离子交换葡糖凝胶梯度色谱法，从突变菌株ＧＢＩＢＵ７发酵液中分离出３０余种蛋白质组分。经测试其中三种是果胶酶，分别为ＰＩ，ＰⅡ和ＰⅢ。     

人类疱疹病毒6B包膜糖蛋白gO在感染细胞中的表达与检测

目的了解人类疱疹病毒6B包膜糖蛋白gO在感染细胞中的表达时间,为今后研发抗病毒药物提供实验依据.方法采用免疫荧光染色法镜检不同时间段的人类疱疹病毒6B感染细胞,并平行收集样本,用蛋白免疫印迹法对样本进行gO 鉴定,以了解其表达状态.结果荧光显微镜观察显示gO开始表达的时间为感染后20 h,在120 h达到高峰,蛋白免疫印迹检测的结果基本与前者相符.结论人类疱疹病毒6B包膜糖蛋白gO为病毒的晚期蛋白.     

Polymorphism of human cytomegalovirus （HCMV） UL144 gene in low passage clinical isolates

To explore the impact of gene polymorphism of human cytomegalovirus （HCMV） on virus virulence, the full-length UL144 gene and partial sequence of glycoprotein B （UL55） gene were sequenced and analyzed for 23 clinical strains of HCMV isolated from urine samples of pediatric patients with congenital or postnatal HCMV infection. Among the 23 isolates, 13 （57 %） were UL144 genotype 1A, 3（13 %） were UL144 genotypes 2 and 7（30 %） were UL144 genotype 3; geographic differences in geno- type distribution were found for both UL144 and gB gene. No UL144 genotypes 1B and 1C were found in this study while these two genotypes were common in HCMV strains isolated in the US. Our results also demonstrated that for all clinical strains of gB genotypes I, III and UL144 genotypes 1A, 2, and 3 found in this study, mother-to-fetus vertical transmission was possible.     

汉坦病毒G1S0.7嵌合基因真核载体的构建及表达

构建含汉坦病毒嵌合基因G1S0.7的真核重组质粒,并在真核细胞中有效表达.从本室前期构建并经测序的重组质粒pShuttle-G1S0.7上双酶切回收得到片段G1S0.7后,克隆入真核表达载体pVAX,并将其通过脂质体介导转染HEK293细胞,表达产物用ELISA和Western-blot进行鉴定.酶切鉴定结果表明,成功构建了含汉坦病毒嵌合基因G1S0.7的重组质粒pVAX-G1S0.7; ELISA检测结果和Western-blot结果显示,汉坦病毒G1S0.7嵌合基因在HEK293细胞中得到了表达,所表达的融合蛋白分子量约90kD,与预期大小一致,并且表达产物可与抗汉坦病毒NP mAb特异性结合.说明所构建的表达载体可在真核细胞中表达出与汉坦病毒抗体有特异性结合活性的融合蛋白,为下一步基因免疫及进一步筛选HFRS基因疫苗候选组分提供实验依据.     

荆豆(Ulex europaeus L.)凝集素Ⅰ的研究

用硫酸铵分级沉淀,当饱和度达40％时,荆豆种子中的荆豆凝集素I就被沉淀出来,再经处理,获得冻干的无盐制剂.当凝集素浓度为7.8μg/mL时,就能凝集人O型血细胞,浓度分别为125μg/mL或500μg/mL时,对人B或A型血发生凝集反应.其凝集O型血的凝集作用可被Fuc所抑制.上述制剂可通过CM—纤维素柱和Sephadex G—200柱2次分子筛过滤而纯化,此纯化的凝集素在PAGE中显示一条蛋白带,浓度为1.25μg/mL时可使O型血和牛精细胞发生凝集反应;浓度为40μg/mL或500μg/mL时,可分别使B型和A型血发生凝集反应.