^31P—NMR谱在人急性早幼粒白血病HL—60细胞分化代谢研究中的应用

ＨＬ－６０细胞是目前研究诱导分化药物的常用细胞株，应用核磁共振＾３１Ｐ谱，观察ＨＬ－６０细胞经分化诱导剂全反式维甲酸和新维甲类化合物ＳＬＭ９１２３作用前后的代谢改变，发现分化后的细胞对ＡＴＰ能量的需求明显增高，膜磷脂的合成前体－磷酸单酯也有明显增加，另外还发现分化后的细胞内ｐＨ值有从偏碱性转为偏酸性的趋势，文中对这些改变的可能机制作了探讨。     

利用~1H-NMR模拟谱研究二核苷酸A2′P(CH_3)5′A的构象性质

根据Altona等人的方法,在利用~1H-NMR模拟谱确定18℃、40℃、70℃三种温度下有关质子化学位移及偶合常数基础上,分析了A2′P(CH_3)5′A的两种非对映异构体(a)和(b)的构象状态。它们与A2′P(OH)5′A相比发现:(1)在18℃时两个核糖环是S型构象占主要成分,但随温度升高有的核糖环趋向于转化成N型构象;(2)磷酸骨架的扭角ε′和β分别改变±2°及±12°;(3)A2′P(CH_3)5′A(a)和(b)的两个核糖环均属部分重叠,并且前者的重叠程度小于后者;(4)随着温度升高,A2′P(CH_3)5′A(a)比A2′P(CH_3)5′A(b)有着更强的去堆积效应。     

^19FNMR在生物医学研究中的应用

核磁共振（ＮＭＲ）是一种无创伤的物理测试方法,它可以直接用于体内和体外的生物样品测定,提供分子水平的信息。正常体内含氟成分很少,测定进无本底信号干扰,因此在体内研究中引进氟代指示剂进行＾１９ＦＮＭＲ研究是目前普遍采用的方法。＾１９ＦＮＭＲ可可以用来测定药物在体内代谢过程、胸内游离的离子如Ｃａ＾２＋和Ｍｇ＾２＋、胞内ｐＨ、氧浓度或氧压力（ｐＯ２）、膜电位、组织温度、血液容积和细胞容积等多项生理生化指     

铯进入红细胞的NMR研究

在生理及生化研究中铯离子的行为受到极大的关注,因为可由它来阐述碱金属离子输运及酶活性等一些基本功能。当所研究的体系中没有K~+时,Cs离子有类似K~+的功能,它能激活Na/K ATPase。Cs进入细胞的速率及激活Na/K ATPase所要求的浓度与被研究系统的条件密切有关。本文用核磁共振谱方法测定红细胞内外的Cs~+及Cs~+进入细胞的速率。结果表明Cs-133的核磁共振谱是研究生物体系离子的分布及输运的极好工具。     

细胞内钠NMR研究用Dy(PPP)的性能研究

应用核磁共振位移试剂原理制备了Dy(ppp)用于核磁共振~(23)Na谱,实现细胞内钠的测定.该方法具有非破环性,可进行细胞内钠变化的动态观察等优点.本文对Dy(ppp)的制备及性能,对生物系统可能产生的毒性或副作用等作了细致的研究.并对V_C、V_B、Hg对人血细胞内钠含量的影响作了动态研究.     

铝与钙调蛋白相互作用及其作用位点的研究

用500MHzNMR研究了铝与钙调蛋白的相互作用,主要研究了铝对钙调蛋白中芳香氨基酸残基(Tyr,His,Phe)构象变化的影响。实验结果表明,铝在钙饱和的钙调蛋白上存在着特异性的结合位点,结合位点数目至少为两个,第一结合位点可能位于钙调蛋白的N端结构域,第二结合位点靠近Ca~(2+)的Ⅲ结合域。Al~(3+)结合引起脱钙的钙调蛋白的构象变化不同于与Ca~(3+)结合引起的构象变化。Al~(3+)在CaM上的结合位点与Ca~(2+)的并不相同。柠檬酸等有机酸对铝的毒性有保护作用,这种保护作用是由于柠檬酸分子对铝的络合。     

核磁共振对水稻胚超微结构的影响

本文报导了水稻种子经核磁共振处理后,其胚细胞超微结构的变化。结果表明,水稻种子经核磁共振处理后,其胚细胞中的线粒体、线粒体内嵴的数量、粗面内质网及高尔基体的数量均有增加,淀粉粒的体积变小。因此,核磁共振处理能促进水稻种子胚细胞内的能量代谢、物质转化与物质运输。     

铂配合物与细胞色素c修饰位点的核磁共振研究

用ＣＭ－５２阳离子交换色谱分离〔ＰｔｄｉｅｎＮＯ３〕Ｃｌ修饰细胞色素ｃ（Ｃｙｔ．ｃ）的反应产物,获得了Ｃｙｔ,ｃ的单标记和双标记衍生物。对此衍生物的核磁共振波谱研究表明,〔ＰｔｄｉｅｎＮＯ３〕Ｃｌ对Ｃｙｔ．ｃ的修饰作用不仅涉及位于蛋白分子表面的氨基酸残基Ｈｉｓ－３３,而且还涉及处于Ｃｙｔ．ｃ分子内部疏水区的Ｔｒｐ－５９。该衍生物为探讨Ｃｙｔ．ｃ中芳香族氨基酸（尤其是Ｔｒｐ－５９）在电子传递过程中的     

蛇毒的核磁共振氢谱研究

本文对不同产地的蝮蛇毒和眼镜蛇毒、五步蛇毒等十六个冻干样品,进行了核磁共振氢谱测试.列出了具有代表性的的氢谱图。从谱图中可看出:每种种属蛇毒均有其特征的核磁共振氢谱,此法在准分子水平上是鉴定蛇毒的一种有效而可靠的方法.     

核磁共振对水稻生长发育和增产效应的研究

用R—24B核磁八振波谱仪,在磁场强度为14092GS,温度35℃,相对湿度<70％的条件下,以60兆的射频磁场,不同照射时间(4～16小时)处理不同状态下的水稻(干种子,萌动种子)攸丰—86,使水稻种子中的质子产生共振,经过三年的实验表明:一定条件下的核磁共振,能促进种子的发芽率和幼根的生长,提高植株的有效分蘖率,结实率,蛋白质含量,对提高作物产量和品质提供了一个新的实验手段和技术,本文还对有关核磁共振的作用机理进行了初步的分析讨论。     

珙桐枝皮中的生物碱甙成分研究

从珙桐枝皮甲醇提取物的水溶性部分得到3个配糖体化合物,经核磁共振和质谱等光谱分析鉴定为1个喹啉类生物碱甙-pumiloside(1)和2个吲哚类生物碱甙-vincosamide(2),strictosidinic acid(3),其中pumiloside是抗肿瘤物质喜树碱的一种生物合成前体,这3个化合物均为首次从该植物中分得。     

Efficient synthesis of jusbetonin, an indolo[3,2-b]quinoline glycoside, and its derivatives

Jusbetonin, an indolo[3,2-b]quinoline alkaloid glycoside originally isolated from Justicia betonica, and its derivatives were synthesized. The key steps in the synthetic strategy were the construction of indolo[3,2-b]quinoline skeleton and efficient coupling with the saccharides, in which the α-d-glycopyranosyl bromides were shown to be effective donors. Primary screening showed that all synthesized compounds possessed moderate proliferation inhibitory activity.     

Microsatellite primers in the Chinese dove tree, Davidia involucrata (Cornaceae), a relic species of the Tertiary

? Premise of the study: The first microsatellite primers were developed for Davidia involucrata, an endangered relic species of the Tertiary in China, to further describe its genetic variability and population structure. ? Methods and Results: Using the Fast Isolation by AFLP of Sequences Containing Repeats (FIASCO) protocol, 15 polymorphic microsatellite loci were isolated and characterized in 20 individuals from the germplasm collections of D. involucrata at the Hunan Forest Botanical Garden. High levels of polymorphism were revealed, with the total number of alleles per locus and the number of alleles per locus per individual ranging from two to 13 and from one to six, respectively. ? Conclusions: The multibanded patterns of microsatellite loci obtained in the current study confirmed that D. involucrata might be a polyploid species. The primers will be useful for studies of genetic diversity and for guiding conservation strategies for D. involucrata.     

Chemical constituents of the seeds of Ammopiptanthus (Leguminosae) and their systematic and ecological significance

Eleven flavonoids including a new flavone glycoside, 7,3′-dihydroxy-4′-methoxyflavone-7-O-β-glucopyranoside, and a quinolizidine alkaloid, lupanine, were isolated from the seeds of two Ammopiptanthus (Leguminosae) species, Ammopiptanthus mongolicus and Ammopiptanthus nanus. 7,3′-Dihydroxy-4′-methoxyflavone and lupanine were the major constituents in the seeds of both species. The patterns of seed flavonoids presented a clear systematic relationship between the two species. The simple seed alkaloid composition was presumed to be responsible for the weak defense capability of the seeds to insect pests in both species.     

Havanine—a steroidal alkaloid glycoside from Solanum havanense

A new steroidal alkaloid glycoside named havanine has been isolated from the leaves of Solanum havanense and its structure elucidated by spectral data as (25S)-O(3)-β-D-glucopyranosyl-16α-acetoxy-22,26-epiminocholesta-5,22(N)-dien-3β-ol.     

大相岭自然保护区珙桐群落植物区系、结构及动态

在多次调查的基础上,对四川大相岭自然保护区珙桐(Davidia involucrata)群落的植物区系组成、群落结构、更新现状以及群落演替进行了探究。结果表明:(1)大相岭自然保护区的植被为亚热带向温带过渡的区系类型,大量古老孑遗属的存在反映出珙桐群落植物区系的孑遗性和古老性。(2)群落整体径级结构呈偏正态分布型,高度级结构呈倒J型,群落结构发展趋势较为稳定。(3)大相岭自然保护区珙桐种群整体年龄结构近似呈金字塔型,为增长型种群。总体来说,珙桐纯林(C类型群落)搭配优势度最优,处于后期稳定型演替阶段,是大相岭自然保护区珙桐群落中的顶极群落。研究认为,设立专门的珙桐保护区开展就地保护是针对此类珙桐原生群落有效的保护方法。     

Development of microsatellite markers for the dove tree, Davidia involucrata (Nyssaceae), a rare endemic from China

? Premise of the study: Microsatellite primers were developed for the endangered Davidia involucrata to assess the population genetics and infer its evolutionary history. ? Methods and Results: Using both the modified magnetic bead hybridization method and the dual-suppression PCR method, we isolated and characterized 12 polymorphic microsatellite loci using 134 individuals from five populations in southwestern China. The number of alleles per locus ranged from six to 21 (mean = 10.8). The expected heterozygosity per locus ranged from 0.404 to 0.918 and observed heterozygosity ranged from 0.015 to 0.821. ? Conclusions: All of the 12 microsatellite markers developed for D. involucrata are polymorphic, and lay a solid foundation for further studies of the population genetics of this famous tree.     

Flavonols and an indole alkaloid skeleton bearing identical acylated glycosidic groups from yellow petals of Papaver nudicaule

From yellow petals of Iceland poppy, besides the known flavonoid gossypitrin, seven kaempferol derivatives were isolated. In addition to kaempferol 3-O-beta-sophoroside and kaempferol 3-O-beta-sophoroside-7-O-beta-glucoside, known from other plants, the mono- and dimalonyl conjugates of the latter were identified by MS and NMR spectroscopy. Structure analyses of a set of co-occurring pigments, the nudicaulins, revealed that they have the identical acylated glycoside moieties attached to a pentacyclic indole alkaloid skeleton for which the structure of 19-(4-hydroxyphenyl)-10H-1,10-ethenochromeno[2,3-b]indole-6,8,18-triol was deduced from MS and NMR as well as chemical and chiroptical methods.     

Lupane,friedelane, oleanane,and ursane triterpenes from the stem of Siphonodon celastrineus Griff

Twenty-one triterpenes consisting of a lupane derivative, two friedelanes, an oleanane derivative, and 17 ursane-type triterpenoids, together with three known triterpenes, three sterols, a fatty acid, a sesquiterpene alkaloid, and a glycerol derivative, were isolated from the stem of Siphonodon celastrineus. Their structures were characterized by various spectroscopic techniques, as well as comparison with literature data. Twenty-seven metabolites of these were evaluated for cytotoxic activity against six human cancer cell lines. The biosynthetic formation of a 1,4-dioxane bridge is also discussed.     

四川卧龙地区珙桐群落的结构与更新研究

 在野外调查基础上,分析了四川卧龙地区珙桐群落的物种构成与生物多样性、群落外貌、结构和珙桐的更新动态。结果表明：1)珙桐群落植物区系丰富、古老、特有性强：2)落叶大、中高位芽和常绿中、小高位芽植物共同构成群落外貌;群落垂直结构复杂,草本层发育;3)在群落演替的前、中期,珙桐种群结构由扩展型变为稳定型;4)珙桐的有性繁殖更新机率随其在群落中重要值的上升而下降。