躯体和内脏传入冲动在大鼠束旁核内的会聚

在麻痹的大鼠上,分别刺激迷走神经、内脏大神经、坐骨神经、腓肠神经、睾丸和副睾,在对侧丘脑束旁核记录到了45个细胞的单位放电。根据诱发反应的潜伏期、时程和放电频谱分布的不同,可将他们分为五种类型,并且认为这些类型和刺激引起的感觉性质有关。在观察到的45单位中,29个的反应具有痛放电的特性,而且对躯体及内脏的传入冲动呈聚合性反应。其中2个单位只对内脏传入冲动产生反应。这项研究的结果表明,束旁核不仅是接受内脏传入的丘脑结构,而且也是一个整合内脏与躯体传入信息的中枢。     

白腹锦鸡机体营养成分的分析与探讨

本文报道笼养和野生白腹锦鸡机体营养成分及其差异。分析表明,笼养的比野生种营养成分含量高的有:腿肌蛋白质高11％,胸肌、腿肌、全血的氨基酸分别高2.64％,1.39％和4.68％,胸肌、腿肌和肝脏的碳水化合物分别高0.076％、0.092％和3.962％,胸肌和腿肌的维生素A分别高188.63和84.09 I.U.,胸肌和腿肌的维生素D分别高47.2和12.8 I.U.。但是胸肌蛋白质含量笼养的比野生的低26％。     

Identification and characterization of a pregnane steroid recognition site that is functionally coupled to an expressed GABAA receptor

Conclusion Based on the pharmacological and biochemical evidence to date, especially that derived from the recombinantly expressed receptor studies, the suggestion that a novel GBRC-linked steroid recognition site exists becomes a cogent argument. The high affinity of the steroid site for certain naturally occurring metabolites of progesterone and glucocorticoids favors a physiologic role for these steroids in the regulation of brain excitability. Clearly, investigations of such a regulatory role is warranted. If present, it provides an important example of endocrine control of a major inhibitory neurotransmitter in the CNS. Moreover, as we gain a greater understanding of the molecular organization of the GBRC, the putative steroid site provides a novel target for the rational design of therapeutic agents for the treatment of anxiety, epilepsy, and insomnia.Special issue dedicated to Dr. Eugene Roberts.     

内皮素对大鼠肠系膜微血管的作用

应用显微电视录象技术可观察到内皮素(ET)对戊巴比妥钠麻醉的 Wistar 大鼠的肠系膜微血管有收缩作用,血液流速减慢,甚至产生微循环障碍,这个作用相当持久,并呈剂量依赖关系。ET 的这个作用远高于去甲肾上腺素。这些结果提示,ET 作为强烈的微血管收缩剂,在微循环紊乱疾病的发病学中可能具有重要意义。     

A nonuniform distribution of excision repair synthesis in nucleosome core DNA

We have investigated the distribution in nucleosome core DNA of nucleotides incorporated by excision repair synthesis occurring immediately after UV irradiation in human cells. We show that the differences previously observed for whole nuclei between the DNase I digestion profiles of repaired DNA (following its refolding into a nucleosome structure) and bulk DNA are obtained for isolated nucleosome core particles. Analysis of the differences obtained indicates that they could reflect a significant difference in the level of repair-incorporated nucleotides at different sites within the core DNA region. To test this possibility directly, we have used exonuclease III digestion of very homogeneous sized core particle DNA to "map" the distribution of repair synthesis in these regions. Our results indicate that in a significant fraction of the nucleosomes the 5' and 3' ends of the core DNA are markedly enhanced in repair-incorporated nucleotides relative to the central region of the core particle. A best fit analysis indicates that a good approximation of the data is obtained for a distribution where the core DNA is uniformly labeled from the 5' end to position 62 and from position 114 to the 3' end, with the 52-base central region being devoid of repair-incorporated nucleotides. This distribution accounts for all of the quantitative differences observed previously between repaired DNA and bulk DNA following the rapid phase of nucleosome rearrangement when it is assumed that linker DNA and the core DNA ends are repaired with equal efficiency and the nucleosome structure of newly repaired DNA is identical with that of bulk chromatin. Furthermore, the 52-base central region that is devoid of repair synthesis contains the lowest frequency cutting sites for DNase I in vitro, as well as the only "internal" locations where two (rather than one) histones interact with a 10-base segment of each DNA strand.     

农田步甲的生物学研究

本文报道12种农田常见步甲的种群动态和捕食习性,施用杀虫剂对步甲的影响。     

Interaction of sodium molybdate with highly purified glucocorticoid receptor

Sodium molybdate can affect the properties of the glucocorticoid receptor in relatively crude preparations. To obtain more information as to whether these effects are due to direct interactions of the ion with the receptor or with other components present in the receptor-containing mixtures, the effects were examined of sodium molybdate on glucocorticoid receptors purified 3000-5000-fold to about 10% homogeneity from rat liver cytosol. The ion was found to: (1) increase the stability of the purified receptor at either 0 or 20 degrees C, although the effect was more pronounced at 20 degrees C (2) induce an apparent dimerization of the receptors as judged by sephadex G-150 gel filtration and sucrose density gradient sedimentation and (3) decrease the ionic strength required for elution of the purified receptor from DEAE-cellulose columns. Although, it is conceivable that each of these observed effects is due to indirect actions of the ion on contaminants in the preparations, it is more likely that the ion exerts its effects through direct interactions with the receptor.     

细菌(Pseudomonas maltophilia)之绒毛膜促性腺激素(hCG)结合物质之研究

 细菌(Pseudomonas moltophilia)与hCG及LH有特异的亲和力,实验发现,细菌之生长曲线与hCG结合活性成平行关系,96小时达高峰,细菌之培养液中含有可溶性结合蛋白,该蛋白经硫酸铵沉淀(80％饱和度)、Sephadex G-100柱层析、DEAE-纤维素柱0.5mol/L NaCl梯度洗脱,再过Sepharose CL-AB柱,收集之活性部分经SDS电泳测得其分子量为70,000,凝胶层析测Stokes radius为41A,Schiff氏染色未见着色带。     

Survival of Shigella in Sewage: II. Effect of Glycerol on Shigella flexneri and Shigella Bacteriophage1

Glycerol (30%) inhibited or delayed the adsorption of Shigella bacteriophage on its host organism, S. flexneri II; glycerol also inhibited or delayed the burst of phage, whether or not adsorption was carried out in the presence of glycerol. Studies of the mechanisms of these effects showed that viscosity and osmotic shock probably were not responsible for either phenomenon. The inhibition of adsorption, however, was proportional to the concentration of glycerol, and appeared to be a function of the hydroxyl groups on the glycerol molecule. The inhibition of burst seemed to be related to the osmotic pressure outside the bacterial cells.     

渗透胁迫对水稻幼苗膜脂过氧化及体内保护系统的影响

两个不同抗旱性的水稻品种对PEG6000渗透胁迫(-0.5MPa,-0.8MPa)的反应具有一定差异。渗透胁迫下SOD,POD和CAT活性及Vc,Car含量与膜脂过氧化水平及膜透性呈一定负相关性,表明这些指标可作为水稻抗旱育种的参考依据。