中药凌霄花的研究进展

本文对中药凌霄花的研究进展进行了综述,包括生药学研究、化学成分研究、药理学研究及临床应用。     

应用PCR技术检测细小病毒H－1DNA在人肝癌与裸鼠正常组织中复制的差异

应用ＰＣＲ技术检测细小病毒Ｈ－１ＤＮＡ在人肝癌与裸鼠正常组织中复制的差异黄青山,马承武,郭兰萍,陈献华,罗祖玉（上海复旦大学生理与生物物理学系,上海２００４３３）关键词：自主性细小病毒Ｈ－１及ＭＶＭ,聚合酶链式反应（ＰＣＲ）,人肝癌模型,抑瘤作用,肿...     

PCR法快速检测临床标本中结核杆菌DNA

应用聚合酶链反应（ＰＣＲ）快速检测临床标本（脑脊液、胸水、腹水、血、痰液）中的结核杆菌ＤＮＡ,特异性扩增片段１２３ｂｐ,为结核杆菌的特异性重复序列ＩＳ６１１０部分基因。ＰＣＲ检测人型结核杆菌的敏感性达１０ｆｇＤＮＡ。临床标本的ＰＣＲ检测阳性率（２３．３％）明显高于抗酸染色涂片（２．９％）和细菌培养（５．７％）的阳性率（Ｐ〈０．０５）。通过设立对照系统及对扩增产物酶切分析,表明该法无假阴性结果（特异     

混合氨基酸含量测定新方法

介绍用交流示波极谱滴定法测混合氨基酸的含量。在ＫＣｌ底液中,利用ＨＣＨＯ将－ＮＨ２封闭,用ＫＯＨ标准液滴定,ＨＣＨＯ同时做指示剂,以极谱图形的敏锐变化指示终点的到过,测定结果准确。     

酸水解蚕蛹制备复合氨基酸的研究

采用硫酸水解法,以蚕蛹制取复合氨基酸产品,得到氨基酸态氮分别为９．０５％和１３．４５％的食用复合氨基粉和精制复合氨基酸粉。食用复合氨基酸粉含有１８种氨基酸,其中必需氨基酸含量为３９．２％。食用复合氨基酸粉的制备方法经工厂小批量生产证实,其工艺简单易行,适合于中小企业采用,该产品的质量优良,生产成本低廉,具有市场竞争力。     

Construction of a novel bifunctional biogenic amine receptor by two point mutations of the H2-histamine receptor.

BACKGROUND: H2-histamine receptors mediate a wide range of physiological functions extending from stimulation of gastric acid secretion to induction of human promyelocyte differentiation. We have previously cloned the H2-histamine receptor gene and noted that only three amino acids on the receptor were sufficient to define its specificity and selectivity. Despite only modest overall amino acid homology (34% amino acid identity and 57.5% similarity) between the H2-histamine receptor and the receptor for another monoamine, the beta 2-adrenergic receptor, there is remarkable similarity at their critical ligand binding sites. We hypothesized that, if the specificity and selectivity of both receptors are invested in just three amino acids, it should be possible to convert one of the receptors into one that recognizes the ligand of the other by simple mutations at only one or two sites. MATERIAL AND METHODS: We explored the effect of two single mutations in the fifth transmembrane domain of the H2-histamine receptor, which encompasses the sites that determine H2 selectivity. The canine H2 receptor gene was mutated at Asp186 and Gly187 (Asp186 to Ala186 and Gly187 to Ser187) by oligonuceotide directed mutagenesis. The coding region of both the wild-type and mutated H2 receptors was subcloned into the eukaryotic expression vector, CMVneo, and stably transfected into Hepa cells and L cells. The biological activity of histamine and epinephrine on the expressed receptor was examined by measurement of cellular cAMP production and inositol trisphosphate formation. RESULTS: Hepa cells transfected with the Ala186-Ser187 mutant H2 receptor demonstrated a biphasic rise in cAMP in response to epinephrine with an early phase (ED50 approximately 10(-11) M) that could be inhibited by both propranolol and cimetidine. Epinephrine also induced IP3 generation in the same cells, a biological response that is characteristic of activation of the wild-type H2 but not of the beta-adrenergic receptor. L cells transfected with the Ala186-Ser187 mutant H2 receptor also responded to epinephrine in a cimetidine and propranolol inhibitable manner. CONCLUSIONS: We converted the H2-histamine receptor into a bifunctional one that has characteristics of both histamine and adrenergic receptors by two simple mutations. These results support the hypothesis that ligand specificity is determined by only a few key points on a receptor regardless of the structure of the remainder of the molecule. Our studies have important implications on the design of pharmacological agents targeted for action at physiological receptors.     

Characterization of cis-acting elements in light regulation of the nuclear gene encoding the A subunit of chloroplast isozymes of glyceraldehyde-3-phosphate dehydrogenase from Arabidopsis thaliana.

We have characterized cis-acting elements involved in light regulation of the nuclear gene (GapA) encoding the A subunit of chloroplast glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in Arabidopsis thaliana. Our results show that a 1.1-kb promoter fragment of the GapA gene is sufficient to confer light inducibility and organ specificity in transgenic Nicotiana tabacum (tobacco) plants, using the beta-glucuronidase gene of Escherichia coli as the reporter gene. Deletion analysis indicates that the -359 to -110 bp region of the GapA gene is necessary for light responsiveness. Within this region there are three copies of a decamer repeat (termed the Gap box) having the consensus sequence 5'-CAAATGAA(A/G)A-3', which has not been characterized in the promoter regions of other light-regulated genes. A deletion (to -247) producing loss of one copy of these elements from the GapA promoter reduces light induction by two- to threefold compared with a promoter deletion (to -359) with all three Gap boxes present, while deletion of all three Gap boxes (to -110) abolishes light induction completely. Gel mobility shift experiments using tobacco nuclei as the source of nuclear proteins show that GapA promoter fragments that contain these repeats bind strongly to a factor in the nuclear extract and that binding can be abolished by synthetic competitors consisting only of a monomer or dimer of the Gap box. Furthermore, a trimer, dimer, and monomer of the Gap box show binding activity and, like the authentic GapA promoter-derived probes, show binding activities that are correlated with Gap box copy number. These results strongly suggest that these repeats play important roles in light regulation of the GapA gene of A. thaliana.     

含金地质体表生带中主要微生物类群的研究

通过对16个含金矿区主要微生物类群的分布、生态结构的研究,发现不同类型的金矿具有不同的微生物类群.金矿矿石与金矿酸水中的自养硫细菌和异养菌分布具有明显差异,酸性水中含自养硫细菌较多,含异养菌极少;金矿氧化带中的异氧菌一般多于自氧硫细菌,其优势菌以芽孢杆菌属中蜡状芽孢杆菌为主.研究结果揭示了金矿中存在的主要微生物类群,对阐明表生金的形成、成岩和蚀变作用具有一定的意义,对发掘生物湿法冶金菌种资源具有重要作用.     

Computation of identity-by-descent proportions shared by two siblings.

I provide a novel approach to computing the mean and variance of the proportion of genetic material shared identical by descent (IBD) by sibling pairs in a specified chromosomal region, conditional on observed marker data. I first show that each chromosome in an offspring can be represented by a two-state Markov chain, with the time parameter being the map distance along the chromosome. On this basis, I show that IBD proportion can be written as a stochastic integral and that the computation of its mean and variance can be reduced to evaluation of an integral of some elementary functions. In addition, I show how Goldgar's model can be extended to include dominance effects. Several examples are provided to illustrate the calculation.     

Stomatal sensitivity to abscisic acid following water deficit stress

Short-and medium-term stresses (1 and 24 h, respectively) wereapplied to detached leaves of Commelina communis L., resultingin both cases in a final leaf cell water potential (