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43.
大豆子叶内酸性磷酸酶活性的超微结构定位 总被引:6,自引:0,他引:6
开花后35~50 d 期间和萌发早期(播种后4~8 d)的大豆(Glycinem ax L.)种子中,酸性磷酸酶主要分布在子叶细胞中的蛋白体内;在内质网内也检测到酸性磷酸酶活性。此外,在萌发早期的部分子叶细胞的质膜外侧及其细胞壁基质中可见密集的酸性磷酸酶活性;而且在近质膜的胞质中常见到一些富含磷酸铅沉淀的胞质小泡,似与质膜融合 相似文献
44.
水稻幼芽细胞生物膜上的赤霉素结合蛋白的结合特性 总被引:1,自引:0,他引:1
在水稻 (Oryza sativa)幼芽中存在膜结合的赤霉素结合蛋白 ,其与 GA3 结合的平衡解离常数(Kd)为 6.5× 1 0 -8mol/ L,总浓度为 0 .3 pmol· mg-1 蛋白质。结合蛋白与 GA3 结合活力在 0℃时比 2 5℃时高 1 4 0 %。它与 GA3 结合的最适 p H为 5。 GA3 与此结合蛋白的结合量随反应时间延长而增加 ,1 h达最大值 ,以后又逐渐下降。 IAA、ABA可与 GA3 竞争赤霉素结合蛋白。 相似文献
45.
独叶草叶二叉分枝脉序中网结脉和盲脉的形态学研究 总被引:13,自引:1,他引:12
对独叶草营养叶二叉分枝脉序及其中的网结脉和盲脉的形态学研究表明:(1)网结脉中2条完全汇合的与靠近脉中完全分离的叶脉之间未发现任何形式的维管束汇合的中间类型及网结脉中具有不同程度的连接脉退化痕迹的事实表明,网结脉不可能由靠近脉产生,相反,由于网结脉中联结脉的退化而形成开放脉;(2)盲脉是通过伴随着齿退化的达齿脉的退化、网结脉中联结脉的间断、非网结脉由分枝处间断三种方式产生的;(3)越裂片脉的出现及其可以形成网结脉的现象表明独叶草营养叶可能曾具有较为复杂的脉序,这种叶脉也呈现出退化的趋势;(4)独叶草营养叶的二叉分枝脉序可能是一种退化性状,而网结脉的出现可能是这种退化过程中的残留痕迹。 相似文献
46.
九种罕见的人类染色体异常核型报告 总被引:1,自引:1,他引:0
ReportonNineRareSpeciesofHumanChromosomalAbnormalKaryotypesHanWeitian;QuOu;YuPing;JiangMiao(LiaoningResearchInstituteofFamilyPlanning,Shenyang110031)自1983年以来,我们对数千例不育及胚胎丢失等生殖异常患者进行细胞遗传学研究,发现大量异常染色体核型,而且异常种类繁多,已报道世界首报人类异常核型25种[1]。最近,在不良妊娠患者中又发现9种异常核型,经湖南医科大学医学细胞遗传学国家培训中心鉴定,为世界首次报道.现报告如下。1病例摘要及核型例1男,30岁,表型及智力正常,其妻子妊娠两次,均在无任何诱因情… 相似文献
47.
Ping Z. Ding Kunio Kawamura James P. Ferris 《Origins of life and evolution of the biosphere》1996,26(2):151-171
The 5-phosphorimidazolide of uridine reacts on Na+-montmorillonite 22A in aqueous solution to give oligomers as long as 7 mers. The maximum chain length increases to 9 mers and the overall oligomer yield increases when 9:1 ImpU, A5 ppA mixtures react under the same conditions. The oligomer yield and maximum chain length decreases with the structure of the added pyrophosphate in the order A5 ppA>A5 ppU>U5 ppU. Structure analysis of individual oligomer fractions was performed by selective enzymatic hydrolyses followed by HPLC analysis of the products. The regioselectivity for 3,5-bond formation is 80–90% in the 9:1 ImpU, A5 ppA reaction, a percentage comparable to that observed in the 9:1 ImpA, A5 ppA reaction. Oligomerization of ImpU is inhibited by addition of dA5 ppdA, and MeppA. No oligomers containing A5 ppU were products of the 9:1 ImpU, A5 ppA reaction, a finding consistent with the simple addition of the ImpU to the A5 ppA and not the rearrangement of an ImpU-A5 ppA adduct. Concentrations of lysine or arginine which were close to that of the ImpU did not inhibit oligomer formation. Treatment of Na+-montmorillonite with 1 M arginine yielded arginine-montmorillonite, an amino acid-mineral adduct which did not catalyze ImpU oligomerization. Neither the 4–9 mers formed in the 9:1 ImpU, A5 ppA reaction nor the 4–9 mers formed by the base hydrolysis of poly(U) served as templates for the formation of oligo(A)s. 相似文献
48.
Ronald W. Wilen Ping Fu Albert J. Robertson Suzanne R. Abrams Nicholas H. Low Lawrence V. Gusta 《Planta》1996,200(1):138-143
The application of abscisic acid (ABA), either as a racemic mixture or as optically resolved isomers, increases freezing tolerance in a bromegrass (Bromus inermis Leyss) cell culture and induces the accumulation of several heat-stable proteins. Two stereoisomers of an ABA analog, 23 dihydroacetylenic abscisyl alcohol (DHA), were used to study the role of ABA-induced processes in the acquisition of freezing tolerance in these cells. Freezing tolerance was unchanged in the presence of (–) DHA (LT50 -9°C), and no increase in heat-stable protein accumulation was detected; however, the (+) enantiomer increased the freezing tolerance (LT50 -13°C) and induced the accumulation of these polypeptides. All three forms of ABA increased freezing tolerance in the bromegrass cells, although (–) ABA was less effective than either (+) or (±) ABA when added at equal concentrations. Cells pretreated with 20 or 50 M (–) DHA displayed lower levels of freezing tolerance following the addition of 2.5, 7.5 or 25 M (±) ABA. Full freezing tolerance could be restored by increasing the concentration of (±) ABA to > 25 M. Pretreatment of cells with (–) DHA (20 or 50 M) had no effect on freezing tolerance when 25 M (+) ABA was added. The induction of freezing tolerance by 25 M (–) ABA was completely inhibited by the presence of 20 M (–) DHA. The accumulation of ABA-responsive heat-stable proteins was inhibited by pretreatment with 20 M (–) DHA in cells treated with 2.5 or 7.5M (+) ABA, and in cells treated with 25 M (–) ABA. The accumulation of these polypeptides was restored when (±) or (+) ABA was added at a concentration of 25 M. The analysis of proteins which cross-reacted with a dehydrin antibody revealed a similar inhibitory pattern as seen with the other ABA-responsive proteins. The effects of the various isomers of ABA and DHA on cell osmolarity and sucrose uptake was also investigated. In both cases, (±) and (+) ABA had pronounced effects on the parameters measured, whereas (–) ABA treated cells gave substantially different results. In both sucrose uptake and cell osmolarity, DHA had no significant effect on the results obtained following (±) or (+) ABA treatment. Maximum freezing tolerance was only observed in cells when both heat-stable protein accumulation and sucrose uptake were observed.Abbreviations ABA
abscisic acid
- DHA
2,3 dihydroacetylenicabscisyl alcohols
- DMSO
dimethyl sulfoxide
- LT50
temperature at which 50% of cells are killed
The authors would like to acknowledge the technical assistance of Angela Bollman, Bruce Ewan and Angela Shaw. This work was supported by grants from the Natural Science and Engineering Research Council of Canada to L.V.G. and N.H.L., and a grant from the University of Saskatchewan to R.W.W. 相似文献
49.
对陆地表层动力学的研究对象、研究内容及其基本理论方法作了阐述,以多学科综合的观点定义了陆地表层系统,包括时空尺度范围的约定、状态变量的选择、物质循环以及外界因子等的讨论;依据物质和能量守恒原理建立了陆地表层系统的非线性控制方程组,表述了各圈层之间物质循环和能量循环过程、反馈关系及其动力学联系;讨论了控制方程组的整体运作功能以及人类活动对陆地表层系统的影响. 相似文献
50.
本文论证了菲波纳斯(Fibonacci)级数与菊花花冠结构的关系,发现了花冠的通用数学模式:花冠(数目)=(5×倍数)十F_n(F_(n-1)+F_(n-2)) 相似文献