甜菜坏死黄脉病毒的分离提纯及其生物化学特性的研究

本研究工作中,建立了一个有效的甜菜坏死黄脉病毒的分离提纯程序,解决了该病毒粒体易于聚集难以提纯的问题,其操作要点是,(1)通过Sepharose 2B柱层析代替超离心,有效地除去一些小分子量核酸杂质;(2)经PEG再次沉淀浓缩后,调整pH至酸牲(pH3.0),使病毒充分悬浮以减少凝聚;(3)在病毒等电点(pH4.8～4.9)条件下,进一步沉淀以纯化病毒。根据病毒提取物的OD260/OD280比值,算出核酸含量约4.5％。核酸电泳出现4条带,分子量分别为:2.25×10~(?),1.8×10~(?),1.05×10~(?),0.75×10~(?)道尔顿。病毒提取物经超速离心出现4个界面,沉淀系数分别为,200.8S,165S,125.8S,100S。说明甜菜坏死黄脉病毒可能是4组分病毒粒体。病毒粒体含一蛋白亚基,分子量约为2.05±0.05×10~4道尔顿,由16种共199个氨基酸组成。     

血友病患者血清中淋巴腺病病毒/人T细胞Ⅲ型病毒抗体检测

对浙江省1982～1984年注射了美国产浓缩Ⅶ因子制剂的18例血友病患者,用酶联免疫吸附法(ELTSA)检测了血清中淋巴腺病病毒/人T细胞Ⅲ型病毒(LAV/HTLV-Ⅲ)抗体,发现4例阳性,并经免疫荧光试验和Western印迹法证实。2例应用了国产浓缩Ⅷ因子者抗体阴性。一例从美国来华旅游死于艾滋病者,LAV/HTLV-Ⅲ抗体阳性。本研究证明,LAV/HTLVⅢ病毒巳通过美国生产的Ⅷ因子制剂传入中国。     

外胚层细胞诱导后的间隙连接

用电镜观察了经受诱导作用之后胚胎细胞的冷冻蚀刻复型膜。和未经诱导作用的对照组比较,早期和中期神经胚的神经上皮细胞以及经过豚鼠骨髓粗提液(BME)——一种有效的异源中胚层诱导物——处理过的早期原肠胚外胚层,它们的间隙连接都处于活跃的动态状态。用图像分析仪测得的间隙连接连接子的排列密度,指出经受过诱导作用的三组分别和未经受诱导作用的对照组比较,计算求出P值,神经上皮两组和对照组的差别为非常显著,BME处理过的细胞和对照组的差别为显著。结合对照组与诱导后胚胎细胞间隙连接连接子的变化讨论了它们在信息传递上可能起的作用。     

An essential tryptophan residue for rabbit muscle creatine kinase

The tryptophan residues in rabbit muscle creatine kinase (ATP:creatine N-phosphotransferase, EC 2.7.3.2) have been modified by dimethyl(2-hydroxy-5-nitrobenzyl) sulfonium bromide after reversible protection of the reactive SH groups. The modification of two tryptophan residues as measured by spectrophotometric titration leads to complete loss of enzymatic activity. Control experiments show that reversible protection of the reactive SH groups as S-sulfonates followed by reduction results in nearly quantitative recovery of enzyme activity. The presence of a 410 nm absorption maximum and the decrease in fluorescence of the modified enzyme indicate the modification of tryptophan residues. At the same time, SH determinations after reduction of the modified enzyme show that the reagent has not affected the protected SH groups. Quantitative treatment of the data (Tsou, C.-L. (1962) Sci. Sin. 11, 1535 1558) shows that among the tryptophan residues modified, one is essential for its catalytic activity. The presence of substrates partially protects the modification of tryptophan residues as well as the inactivation, suggesting that the essential tryptophan residue is situated at the active site of this enzyme.     

Inhibitory effect of molecular hydrogen on C2H2-reducing activity in Anabaena 7120 preilluminated in red or blue light

Molecular hydrogen inhibits nitrogenase activity in Anabaena pre-illuminated with red or blue light. The inhibitory effect of molecular hydrogen decreased in the presence of oxygen and several electron acceptors. When NH₄Cl and urea were added simultaneously with molecular hydrogen, marked synergistic inhibitory effects took place. The inhibitory effect of molecular hydrogen disappeared or was weakened after the suppression of hydrogenase activity. The addition of O₂ and electron acceptors to systems showed no enhancing effect on the C₂H₂-reducing activity.     

Regional Distribution of Calmodulin Activity in Rat Brain

Calmodulin activity in 68 discrete areas of rat brain, obtained by micropunch technique, was assessed by its capacity to activate a calmodulin-sensitive form of phosphodiesterase. In general, the activity of calmodulin was higher in the telencephalon, limbic system, and hypothalamus than in the mesencephalon, pons, cerebellum, and medulla. However, there were substantial differences in calmodulin activity in discrete nuclei of each region. The regional distribution of calmodulin activity in rat brain does not appear to correlate with that of any of the known putative neurotransmitters or peptides.     

向日葵未受精胚珠培养时胚状体发生的显微观察

由开花前1—4天的向日葵子房中取出胚珠,在液体培养基上进行漂浮培养,诱导了未受精的卵细胞发育为单倍体的胚状体.亦诱导了珠被绒毡层产生胚状体。对两种胚状体的发生和发育过程及其形态发生特点作了显微观察与描述。     

Human chromosome hot points

Summary Peripheral lymphocytes from 16 healthy adults, 9 pregnant women, and 3 fragile X syndrome patients were cultured in Eagle's minimum essential medium without folic acid (MEM-FA). The addition of 2mM, 4mM, or 8mM uridine 24h or 72h prior to harvest resulted in increases of chromosome gaps or breaks, especially at hot points 3p14, 16q23-24, and at fragile site Xq27. Pregnant women showed higher frequencies of 3p14 breaks and total chromosome breaks than men and non-pregnant women. The other chromosome regions, such as 6q26, 7q23, 7q35, 6p25, Xp22, 14q23 and 11p13, also frequently showed gaps or breaks. The results indicated that the unbalance of nucleotide pools was one of the causes of chromosome breakages. The higher frequencies of chromosome gaps and breaks under the condition of thymidylate stress may be due to the misincorporation of uracil instead of thymine into DNA.     

高压氧不同给氧时机对豚鼠听觉声损伤防治效果的观察

将四组豚鼠在125dBSPL,1KHz强声中暴露3小时。一组动物于声暴露前后吸空气作为对照组。其余三组动物吸2ATA高压氧(HBO),每次30分钟。其中于声暴露前吸1次者为预防组;于声暴露后连续吸14天次者为治疗组;于声暴露前吸1次,声后吸14天次者为HBO防治组。声暴露后,各组动物短声诱发皮层听区电位听阈上升。对照组听力损失最重,达70dB;预防组和防治组仅损失53dB和51dB(同对照组比P<0.01);治疗组损失68.5dB。短纯音测昕结果与此类似。对照组耳蜗病理损伤长度平均为527μm;预防组和防治组分别为142μm和106μm(P<0.05);治疗组为295μm。由此可以认为HBO对声损伤具有显著的预防作用。 文中讨论了高压氧的预防机理及其治疗作用