人胃癌不同周期细胞膜表面ConA受体的分布与侧向运动

本文研究了人胃低分化粘液性腺癌细胞MGC 80-3不同周期时相中ConA受体的分布与侧向运动。MGc 80-3细胞经同步化培养,用F-ConA标记。被标记细胞中G_1、S和G_2期呈不连续的分布,但它们之间又存在显著的差异。M期呈较均匀的强荧光分布(与其它时相细胞比较)。荧光漂白恢复方法测定ConA受体复合物侧向运动表明:各个周期时相之间不仅运动方式不同,而且运动速率也有显著差异。M期与G_1期主要表现出扩散型运动;而S期与G_2期表现为流动型运动。G_1期的扩散系数大干M期的;S期的流动速率大于G_2期的。但可动分子百分比以G_2期最高。这些结果表明了ConA受体的动力学性质。它受到细胞周期的调节。     

棉属栽培种与野生种杂交的不亲和性

本文研究了棉属栽培种与野生种杂交的不亲和性,试验材料涉及5个染色体组,包括2个栽培种(陆地棉和中棉)和5个野生种(戴维逊氏棉、瑟伯氏棉、三裂棉、阿拉伯棉和比克氏棉)。以陆地棉作母本,异己花粉管在花柱中生长缓慢,有花粉管胚珠低于10%,陆地棉×戴维逊氏棉杂种胚在子叶期坏死。以中棉作母本,不亲和性主要表现在受精后的胚胎发育过程中。     

“生态效益”的内涵及其特征

纵观全球,伴随着社会、经济的迅速发展,环境问题已成为一个日趋突出的世界性问题,并对人民生命健康和社会、经济的持续稳定发展带来了严重威胁。生态学界强烈地呼吁人类要保护自然,维持生态平衡,合理地开发利用自然资源,呼吁人类在经济发展中能正确处理经济发展-环境保护,经济效益-生态效益的关系,在实践中取得了一定成效。然而,迄今为止我们对“生态效益”的内涵及特征还没有完全认识和了解,这在相当程度上妨碍了人们在社会生产中对提高生态效益的关注,因此,本问题亟待在理论上加以认识。本文试图对此做一点有益的探讨。     

应用酶联免疫吸附试验检测不同类型乙型肝炎中激活补体类HBsAg循环免疫复合物

本文以抗人C_(?)的羊IgG为包被抗体,以HRP-HBs抗体为指示抗体,建立了可检测激活补体类HBsAg循环免疫复合物(HBsAg/C3-CIC)的C_3捕捉法酶联免疫吸附试验。检测了236例六种类型临床诊断为乙型肝炎的病人血清标本,其阳性率分别为:无症状携带者(ASC)12.9％(4/31),急性肝炎(AH)36.7％(22/60),慢性迁延性肝炎(CPH)33.3％(7/21),慢性活动性肝炎(CAH)59.6％(34/57),重型肝炎(SH)77.8％(14/18),肝炎后肝硬化(PLC)67.3％(33/49),阳性率与肝损严重程度明显相关(P<0.01)。认为HBs-Ag/C3-CIC可能在乙型肝炎病毒引起的慢性活动性肝炎、重型肝炎和肝炎后肝硬化的发病过程中起重要作用,并可作为乙型肝炎的诊断、临床分型和预后判断的指标之一。     

城市中的伴人植物

伴人植物分布于城市中的许多地方,常被视为杂草而清除。本文论述了城市伴人植物的特点、分布,及其在城市环境保护及美化中的作用,最后列出了北方城市中一些常见伴人植物的名称。     

高胆固醇高脂肪膳食对家兔β-VLDL组成及其与巨噬细胞相互作用的影响的初步研究

给家兔喂以1％胆固醇及10％菜油(A组)或猪油(B组)50多天后A组血胆固醇水平(824.2±265.1mg/dl)明显低于B组(1666±693.8mg/dl);A组甘油三酯水平(51.9±19.1mg/dl)亦低于B组(104±40.2mg/dl)。二组家兔的β—VLDL的脂类组成无差别,但A组β—VLDL的apoE高于B组,分别为45.2％及37.5％。高分子量apoB(apoB_h)为33.6％,低于B组β-VLDL(47.3％)。A组β-VLDL促进小鼠腹腔巨噬细胞胆固醇堆积的程度大于B组,可能与apoE含量高有关。我们认为多不饱和脂酸减轻动脉粥样硬化(As)的作用不在于改变脂蛋白构成后阻碍泡沫细胞的形成而是促进β—VLDL从体内清除。     

Nucleocytoplasmic transport is enhanced concomitant with nuclear accumulation of epidermal growth factor (EGF) binding activity in both 3T3-1 and EGF receptor reconstituted NR-6 fibroblasts

Measurements of nucleocytoplasmic transport of fluorescent-labeled macromolecules were performed in both an EGF-nonresponsive mutant fibroblast line (3T3-NR6) and in the same cell line reconstituted with active EGF receptors derived from rat hepatic membrane fraction. Immunolocalization studies of exogenously incorporated EGF receptors in reconstituted 3T3-NR6 fibroblasts demonstrated predominantly intracellular localization. The EGF receptor constructs also showed EGF-stimulated incorporation of [3H]thymidine, providing biochemical evidence for functional integration of the exogenously supplied EGF receptors into the reconstituted fibroblasts. Additional support for the functional incorporation of receptor may be inferred from the enhanced cellular accumulation of 125I-EGF in cells treated with chloroquine and leupeptin. 125I-EGF binding and transnuclear macromolecular transport measurements in mutant and reconstituted cells, in conjunction with such measurements on nuclei isolated from these cells, provide data consistent with a growth factor/nuclear signaling mechanism dependent on the nuclear acquisition of EGF binding activity from the plasma membrane.     

Purification of the 110-kilodalton glycoprotein receptor for mouse hepatitis virus (MHV)-A59 from mouse liver and identification of a nonfunctional, homologous protein in MHV-resistant SJL/J mice.

The receptor for mouse hepatitis virus strain A59 (MHV-A59) is a 110- to 120-kilodalton (kDa) glycoprotein which is expressed in MHV-susceptible mouse strains on the membranes of hepatocytes, intestinal epithelial cells, and macrophages. SJL/J mice, which are highly resistant to MHV-A59, were previously shown to lack detectable levels of receptor by using either solid-phase virus receptor assays or binding of a monoclonal anti-receptor antibody (MAb) which blocks infection of MHV-susceptible mouse cells. This MAb was used for affinity purification of the receptor glycoprotein from livers of MHV-susceptible Swiss Webster mice. The MHV receptor and an antigenically related protein of 48 to 58 kDa were copurified and then separated by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The first 15 amino acids of the receptor were sequenced, and a synthetic peptide of this amino acid sequence was prepared. Rabbit antiserum made against this peptide bound to the MHV receptor glycoprotein and the 48- to 58-kDa protein from livers of MHV-susceptible BALB/c mice and Swiss Webster mice and from the intestinal brush border of BALB/c mice. In immunoblots of intestinal brush border and hepatocyte membranes of MHV-resistant SJL/J mice, the antibody against the amino terminus of the receptor identified proteins that are 5 to 10 kDa smaller than the MHV receptor and the 48- to 58-kDa related protein from Swiss Webster or BALB/c mice. Thus, SJL/J mice express a protein which shares some sequence homology with the MHV receptor but which lacks virus-binding activity and is not recognized by the blocking anti-receptor MAb. These results suggest that resistance of SJL/J mice to MHV-A59 may be due to absence or mutation of the virus-binding domain in the nonfunctional receptor homolog in SJL/J mice.