Effects of two free radical scavengers and intermittent warming on chilling injury and polar lipid composition of cucumber and sweet pepper fruits

Cucumber (Cucumis sativus L.) and sweet pepper (Capsicum annuumL.) fruits were chilled at 2.5?C for different periods and thentransferred to 20?C and subsequently evaluated for chillinginjury. Sodium benzoate at 10 nw or ethoxyquin at 9.2 mM, appliedas a 5-min dip before chilling, increased the degree of unsaturationof 18-carbon fatty acids in the polar lipids and reduced theseverity of chilling injury. Intermittent warming to 20?C for24 hr at 3-day intervals also alleviated the chilling symptomsand increased fatty acid unsaturation of the polar lipids incucumber and pepper fruits. (Received August 22, 1978; )     

内蒙羊草草原群落光合速率日变化及其与环境条件之间相互关系的初步研究

群落光合生态的研究是植物物质生产研究的基础之一。通过群落光合速率及其与环境条件关系的研究,阐明制约光合的有关变量,就可以为估算植物的潜在生产力提供依据。为此进行群落光合特性以及与外界环境关系的研究,是群落光合生态研究中不可缺少的一个环节。 有关群落光合日变化及其与环境条件相互关系的研究已有不少报道(户刈义次,1979;Singh et al.,1980;Migasaka et al.,1978;权永忍,1980),但以作物方面的研究较为突出,而对天然群落的研究较少。 我们根据同化箱的气体交换法原理(群落光合研究的方法很多),试制了一台简易光合测定车。利用这个装置,于1981年7、8月间,对内蒙锡盟白音锡勒地区的羊草草原群落进行     

蛇毒抗肝癌作用的研究

眼镜蛇毒具有抗肝癌作用.我们采用多种小鼠移植性肝癌研究了眼镜蛇毒抗肝癌作用.通过多项指标的体内实验证实眼镜蛇毒经腹腔给药,对小鼠腹水型肝癌 H_(22)(HepA)均有明显的抑制作用,其生存时间,癌重生长抑制率接近5-Fu.我们认为眼镜蛇毒是一种新型的,有一定抗癌活性药物,有在临床上进一步研究的价值.     

中国种子植物区系定量化研究——Ⅰ区域性种子植物区系研究实用程序工作原理(QX—系列程序)

本文根据吴征镒教授对中国种子植物属分市区类型研究结果,研制出定量化研究区域性种子植物区系的电子计算机程序,应用本程序可完成某区系的分布区类型统计分析,科属组成分析和与其它地区以共有属关系构建的相似性系数的谁知盘中计算,同时可大量节省研究人员的劳动强度和时间,对提高研究水平有一定的效果。     

1,25-双羟胆钙化醇及其受体含量检测的实验研究

 建立了一种改良的血清1,25-双羟胆钙化醇(1,25-Dihydroxycholecalciferol,DHCC)超微量放射受体检测(RRA)技术。完成了灵敏度、精密度、准确度、稳定性及特异性等技术指标。报告了我国健康青年血清DHCC正常值;检测了先天性佝偻病、青春期佝偻病病人及患肾性骨病奶牛等血清DHCC水平。 根据配体与受体相互结合的定量关系,建立了DHCCR(DHCC受体)检测技术。在游离与结合配基分离方面,除建立与比较了DCC(葡聚糖包埋的活性炭)及HAP(羟基磷灰石)方法外,还首次将IEF(等电聚焦电泳)应用于DHCCR分离技术。对佝偻病鸡小肠粘膜上皮细胞受体含量进行了检测并比较了鸡小肠、输卵管壳腺及肝组织DHCCR含量。     

Structural and functional studies of cross-linked Go protein subunits

The guanine nucleotide binding proteins (G proteins) that couple hormone and other receptors to a variety of intracellular effector enzymes and ion channels are heterotrimers of alpha, beta, and gamma subunits. One way to study the interfaces between subunits is to analyze the consequences of chemically cross-linking them. We have used 1,6-bismaleimidohexane (BMH), a homobifunctional cross-linking reagent that reacts with sulfhydryl groups, to cross-link alpha to beta subunits of Go and Gi-1. Two cross-linked products are formed from each G protein with apparent molecular masses of 140 and 122 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both bands formed from Go reacted with anti-alpha o and anti-beta antibody. The mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis is anomalous since the undenatured, cross-linked proteins have the same Stokes radius as the native, uncross-linked alpha beta gamma heterotrimer. Therefore, each cross-linked product contains one alpha and one beta subunit. Activation of Go by guanosine 5'-3-O-(thio)triphosphate (GTP gamma S) does not prevent cross-linking of alpha to beta gamma, consistent with an equilibrium between associated and dissociated subunits even in the presence of GTP gamma S. The same cross-linked products of Go are formed in brain membranes reacted with BMH as are formed in solution, indicating that the residues cross-linked by BMH in the pure protein are accessible when Go is membrane bound. Analysis of tryptic peptides formed from the cross-linked products indicates that the alpha subunit is cross-linked to the 26-kDa carboxyl-terminal portion of the beta subunit. The cross-linked G protein is functional, and its alpha subunit can change conformation upon binding GTP gamma S. GTP gamma S stabilizes alpha o to digestion by trypsin (Winslow, J.W., Van Amsterdam, J.R., and Neer, E.J. (1986) J. Biol. Chem. 261, 7571-7579) and also stabilizes the alpha subunit in the cross-linked product. Cross-linked G o can be ADP-ribosylated by pertussis toxin. This ADP-ribosylation is inhibited by GTP gamma S with a concentration dependence that is indistinguishable from that of the control, uncross-linked G o. These two kinds of experiments indicate that alpha o is able to change its conformation even though it cannot separate completely from beta gamma. Thus, although dissociation of the subunits accompanies activation of G o in solution, it is not obligatory for a conformational change to occur in the alpha subunit.     

土壤重金属污染的酶学诊断:紫色土Cd、Cu、Pb和As对水稻根系脱氢酶的影响

本文通过酸性紫色土和石灰性紫色土中不同浓度Cd、Cu、Pb、As对水稻根系脱氢酶的影响研究,揭示了脱氢酶受抑制与产生抗性的过程。在低浓度时,土壤Cd、Cu、Pb、As对脱氢酶的影响较敏感,能因元素的不同性质反映土壤类型影响的差别。最后,以脱氢酶受抑制与初始抗性峰出现的转折点相应的土壤浓度为依据,确定了两种紫色土Cd、Cu、Pb、As的临界浓度。     

Idiotypic and antiidiotypic T and B lymphocytes in myasthenia gravis.

The prevalence of Id and anti-Id T and B cells as measured by their reactivities with two human mAb, one antiacetylcholine receptor mAb and one anti-Id mAb, was studied in 38 patients with myasthenia gravis and in 27 healthy individuals. Id and anti-Id T cells were estimated by enumerating the numbers of cells secreting IFN-gamma in response to 10 pg/ml of the human mAb. T cell stimulation, measured as numbers of IFN-gamma-secreting cells that exceeded the mean + 2 SD of controls, was induced by the Id mAb in 78.9% of the patients and in 7.4% of the controls, whereas the anti-Id mAb-stimulated T cells in 55.3% of the patients and in 3.7% of the controls. The mean value of the Id and anti-Id-reactive T cells in the patients was 18.3/10(5) and 10.1/10(5) PBMC, respectively. B cells secreting IgM antibodies binding to the human mAb were increased in patients with myasthenia gravis compared to healthy controls. Seventy-five percent of the patients and 12% of the controls had B cells secreting IgM antibodies binding to the Id mAb, although 89% of the patients and 16% of the controls had B cells secreting IgM antibodies binding to the anti-Id mAb. The mean value of B cells secreting IgM antibodies binding to Id or anti-Id mAb in the patients were 7.4 cells/10(6) and 5.5 cells/10(6) PBMC, respectively. We conclude that Id and anti-Id T and B cells are present in myasthenia gravis. These methods allow a quantitative estimation of T and B cells with defined specificities and thus a way of mapping the repertoire of lymphocytes.     

水稻野败型细胞质雄性不育系和其保持系蛋白质多肽的比较研究

应用单向SDS—PAGE结合蛋白质铬银染色技术对水稻野败型细胞质雄性不育系珍汕97A和其保持系的叶绿体、线粒体和细胞质的蛋白质多肽进行了比较研究,发现两系之间存在明显的差异,生殖器官(穗子)上的差异比营养器官(叶片)上的差异更为显著。在成熟穗上,叶绿体可溶性蛋白不育系有25条带,保持系仅16条带,两者间有19个多肽不同;线粒体可溶性蛋白不育系有28条带,保持系比不育系少30.1和21.8KD两个多肽;细胞质可溶性蛋白丙酮沉淀物的水溶性蛋白组分不育系有24条带,保持系为29条带,两系间却有7条多肽存在差别;细胞质可溶性蛋白丙酮沉淀物的SDS-增溶性蛋白组分不育系有18条带,保持系只有11条带,两者间亦有7条多肽出现差异。由此可以看出,水稻野败型CMS表型的表达可能需要较多个基因的启动和关闭,既与叶绿体和线粒体有关,还涉及到核基因组的作用。