中药大黄的生物化学研究——蒽醌衍生物对线粒体NADH氧化酶和琥珀酸氧化酶的抑制作用

 实验结果表明:(1)大黄素对线粒体NADH氧化酶和琥珀酸氧化酶有很强的抑制作用,其作用随药物浓度的增大而增强,并呈双曲线型,50％抑制浓度分别为2.5μg/ml和11.5μg/ml。而其它四种蒽醌衍生物如大黄酸、芦荟大黄素、大黄素甲醚和大黄酚对这两种氧化酶的抑制作用不明显,药物浓度为60μg/ml,抑制率均低于20％。(2)拮抗实验表明:核黄素、牛血清蛋白(BSA)能拮抗大黄素对线粒体NADH氧化酶的抑制作用。核黄素(3.3×10~(-4)mol/L)和BSA(1.6mg/ml)对大黄素抑制NADH氧化酶的恢复率分别为50.3％和44.6％,且恢复率随拮抗剂浓度的增加而增加。     

On non-metric multidimensional scaling ordination and interpretation of the matorral vegetation in lowland Murcía

The plant-environment relationships in a range of matorral communities, having different rainfall conditions in semi-arid lowland habitats in Murcía, S.E. Spain, were examined using the non-metric multidimensional scaling ordination technique. Hypotheses on floristic variations were derived based on an interpretative strategy which involved a site configuration rotation, followed by stepwise multiple regression analysis. An environmental data set was used to isolate variables associated with site co-ordinate trends. Results showed that floristic variation in these communities was mainly determined by aspect induced radiation receipt. Besides, most environmental trends in the study areas were found to be oblique to original site ordination axes and configuration rotation seemed to be a prerequisite in quantitative interpretation. The interpretative strategy introduced in this study was effective. It enhanced straightforward, quantitative and objective interpretation whereby inductive inferences on environmental trends could be readily formulated.Abbreviations ARAD radiation receipt surrogate - DEPTH soil depth - DISTURB disturbance index - NMDS non-metric multidimensional scaling - NUT nutrient scalar - SLOPE slope angle - TEXTIN texture index     

微量元素对虫草蝠蛾幼虫生长发育的影响

按月采样,分析测定虫草蝠蛾幼虫体微量元素的组成。应用Q模式系统聚类方法,分析了幼虫受环境影响引起的元素代谢变化。结果表明虫体所含元素与环境温度的变化及自身的生理活动密切相关。5、10月份幼虫组的元素含量相近,前者正当幼虫结束休眠后恢复活动的时期,后者是幼虫处于准备进入越冬的前期,两组幼虫此时均处于取食高峰期。3、4月份组的亦较接近,幼虫正渐恢复活动但不取食。8月份幼虫蜕皮前后,消耗较大,需摄取大量食物。计算结果表明7、9月份的元素含量接近,这与上述现象有一定联系;应用对应因子分析法得到的结果是:元素Fe、P对10、11月份幼虫组的贡献值显著;Na、Ca、Mg对8、9月份的贡献值显著;Cu、Zn、Co、Cd、Si对4、5月份的贡献值显著。     

污水和污水土地处理系统中各种水质对华西蟾蜍蝌蚪红细胞微核率的影响

本文使用蝌蚪红细胞微核率作为指示器研究明通河污水和用污水土地处理系统处理后水质的致突变性。蝌蚪在各种水样品中暴露7天。采心脏血制片。在对照组中,微核率分别为4.40‰和4.68‰。1/4明通河污水组诱发蝌蚪的微核率是17.01‰。同对照组相比有明显的差异。     

红腹锦鸡和白腹锦鸡卵壳的超微结构

本文报道了锦鸡属——白腹锦鸡和红腹锦鸡卵壳的气孔、外壳膜、锥体层、木栅层的超微结构。并对两者的卵壳进行了比较。     

A CD44-like endothelial cell transmembrane glycoprotein (GP116) interacts with extracellular matrix and ankyrin.

We used complementary biochemical and immunological techniques to establish that an endothelial cell transmembrane glycoprotein, GP116, is a CD44-like molecule and binds directly both to extracellular matrix components (e.g., hyaluronic acid) and to ankyrin. The specific characteristics of GP116 are as follows: (i) GP116 can be surface labeled with Na 125I and contains a wheat germ agglutinin-binding site(s), indicating that it has an extracellular domain; (ii) GP116 displays immunological cross-reactivity with a panel of CD44 antibodies, shares some peptide similarity with CD44, and has a similar 52-kDa precursor molecule, indicating that it is a CD44-like molecule; (iii) GP116 displays specific hyaluronic acid-binding properties, indicating that it is a hyaluronic acid receptor; (iv) GP116 can be phosphorylated by endogenous protein kinase C activated by 12-O-tetradecanoylphorbol-13-acetate and by exogenously added protein kinase C; and (v) GP116 and a 20-kDa tryptic polypeptide fragment of GP116 from the intracellular domain are capable of binding the membrane-cytoskeleton linker molecule, ankyrin. Furthermore, phosphorylation of GP116 by protein kinase C significantly enhances GP116 binding to ankyrin. Together, these findings strongly suggest that phosphorylation of the transmembrane glycoprotein GP116 (a CD44-like molecule) by protein kinase C is required for effective GP116-ankyrin interaction during endothelial cell adhesion events.     

Antioxidant drug mechanisms: transition metal-binding and vasodilation

In our work evaluating the antioxidant properties of a number of cardiovascular drugs, we have emphasized the importance of lipophilicity as a property contributing to antioxidant potency. Thus, the dihydropyridine calcium channel blockers and propranolol, one of the most lipophilic beta-blockers, were found to exhibit the greatest potency in membrane and cellular models. Both beta-blockers and calcium channel blockers are classified as antihypertensive agents. We found that the specific chemical moieties of various drugs may participate in the antioxidant mechanism of action. While reviewing relevant work from the past literature, it became apparent that some of the chemical moieties of antihypertensive and vasodilator drugs may bind transition metals. Thus, this present review focuses on common properties of transition metal-interaction that are shared, to a greater or lesser degree, by a number of vasoactive drugs and chemical agents. Although this observation has been pursued by other investigators in the past, we submit that the potential relevance to the newer pharmacological agents needs to be explored further. In addition, new information regarding the role of transition metals and free radicals involving vascular cells focuses greater importance on transition metal-interaction as a potential mechanism in vasodilation. This review does not intend to be inclusive of all chemical structures capable of binding transition metals; only those that are clinically relevant will be considered in some detail. Potential mechanisms of metal-chelating actions leading to vasodilation are also discussed.     

电刺激大鼠尾核头部镇痛的中枢效应—[^3H]—2脱氧...

Sokoloff's 2-deoxyglucose (2-DG) autoradiographic technique was used to identify changes of glucose metabolic rate in the rat brain following unilateral stimulation of the head of the caudate nucleus. The results were as follows. The local glucose metabolic rate after noxious stimulation was increased in the somatosensory cortex, cingulate cortex, ventroposterior and parafascicular nucleus of the thalamus, septal area, habenular nucleus, head of caudate nucleus, periaqueductal gray (PAG) and dorsal raphe nucleus (P < 0.05). After stimulating the head of the caudate nucleus, the local glucose metabolic rate of nucleus raphe magnus (rm) and nucleus paragigantocellularis (pgcl) was increased significantly and that of the PAG and dorsal raphe nucleus had a tendency to increase, while stimulation of the head of caudate nucleus could partially abolish the increased glucose metabolic rate in the somatosensory cortex, cingulate cortex, ventroposterior and parafascicular nucleus of the thalamus, septal area and habenular nucleus as induced by noxious stimulation. These results suggest that caudate stimulation is able to depress the activation of some brain structures related to nociception and to activate those related to antinociception. The pgcl, rm, PAG and dorsal raphe nucleus might be the key structures participating in the caudate stimulation produced analgesia.     

Construction and characterization of a region-specific microdissection library from human chromosome 2q35-q37.

A region-specific genomic library for human chromosome 2q35-q37 has been constructed using the microdissection and polymerase chain reaction-mediated linker-adaptor microcloning method. Twenty fragments from the chromosome region 2q35-q37 were dissected and a library consisting of 20,000 recombinant microclones was obtained. The insert size ranged between 50 and 800 bp, with a mean of approximately 270 bp. About 50-60% of the microclones contained unique sequences. The microdissection library has been demonstrated to derive from the dissected region 2q35-q37 by chromosome painting using the fluorescence in situ hybridization (FISH) technique. Southern blot analysis of the unique sequence microclones from the library showed that 54% (26/48) of the clones are of human origin and chromosome 2 specific. Four of these microclones have been further mapped to the 2q37 region by using a cell hybrid containing only 2q37. The unique sequence microclones have also been characterized for their insert size and the hybridizing genomic fragments cleaved with HindIII. As shown previously, these microclones will be useful in isolating corresponding yeast artificial chromosome (YAC) clones with large inserts for high-resolution physical mapping and also in screening cDNA libraries to isolate expressed gene sequences as candidate genes to facilitate search for the crucial genes underlying genetic diseases and specific forms of cancer assigned to the region.     

Zinc deficiency and the formation of white structures in immature embryo cultures of wheat (Triticum aestivum L.)

The effect of microelements on the induction of embryogenic callus from epiblast and scutellum of wheat (Triticum aestivum L.) embryos was studied by the sequential omission of each of the microelements from Murashige & Skoog medium. Omission of iron caused a marked decrease in yield and poor shoot formation from embryogenic callus. The yield of embryogenic callus on medium without added manganese was also reduced. Omission of boron, copper-cobalt, iodine, and molybdenum had little effect on the induction of embryogenic epiblast callus. By contrast there was a marked increase in the formation of white structures on the medium without any microelements or, specifically without addition of zinc. Since the formation of typical embryoids of wheat is associated with the formation of white structures, our result highlights the importance of certain microelements on somatic embryogenesis of wheat.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - MS medium Murashige & Skoog medium