共查询到20条相似文献，搜索用时 218 毫秒
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目的合成几种醛胺二糖化合物,通过对其结构和生化性能的研究,明确了不同的醛胺二糖结构对其生物活性的作用机制。方法:采用化学合成的方法,以戊糖缩二胺(即化合物[1])为原料,合成一系列有机化合物[2-8]。结果:利用H.NMR对这些化合物进行表征,确认其结构。通过对革兰氏细菌的抗菌实验进行生物化学方面的研究。结论:实验结果表明这些醛胺二糖化合物均具有较高的抗菌活性,尤其是化合物[2-4]。 相似文献
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通过对单子叶植物和毛茛科以及”睡莲目”植物中生物碱、甾体化合物、三萜化合物、氰甙
和脂肪酸等五类化学成份的比较分析，作者认为毛茛科与百合目有着密切的亲缘关系，因而支
持单子叶植物毛茛—百合起源的主张，不赞同苏联学者Takhtajan关于单子叶植物莼菜—泽泻起源的观点。 相似文献
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植物多糖生物学活性的研究进展 总被引：1，自引：0，他引：1
正多糖广泛存在于动植物体内和微生物的细胞壁中,结合了脂类与蛋白质,是一类重要的信息分子。多糖主要分为植物多糖、动物多糖和微生物多糖等几类。从前植物多糖只被看成是一种生命组织物质和能量物质,经后来科学研究发现,多糖及糖复合物参与和介导了细胞的各种生命现象的调节,具有广泛的生物学作用。除作为植物体内重要的营养物质,植物多糖还参与了细胞识别、物质运输和机体免疫调节等生命活动。多糖来源广泛,可通过化学手 相似文献
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丘月 《大科技．科学之谜》2009,(5):39-39
电击人可以把人击倒,那么电击植物呢？下面的实验可以告诉我们结果。美国亚利桑那州立大学的研究者把豌豆的根置于较低电流的环境中,结果豌豆秧产生了比普通豌豆秧多12倍的豌豆素（一种抗真菌的化合物）!当用电击一种类似紫花苜蓿的植物细胞的培养基时,竟然使这种植物细胞中的一种化合物含量提高了168倍,另外还有54种化合物含量提高了两倍以上。 相似文献
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目的:分离提取马蔺子中的活性化合物。方法:使用硅胶柱层析梯度洗脱分离化合物,制备型高效液相进一步纯化化合物。结果:从马蔺子中首次分离出白藜芦醇四聚体(r-2-viniferin)和白藜芦醇二聚体(trans-ε-viniferin)。马蔺子是鸢尾科植物马蔺的种子,具有清热,利湿,止血,解毒。治黄疸,泻痢,吐血,衄血,血崩,白带,喉痹,痈肿等作用[1,2]。本文使用硅胶柱层析从马蔺子中分离出了白藜芦醇四聚体和二聚体,制备型高效液相纯化这两种化合物,结合液相质谱和核磁共振解析出其化合物的结构。之前很多研究已经发现这两种化合物存在葡萄科等植物中[3],这是首次在马蔺子中提取出来。 相似文献
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Sanja Grkovic Rajko Nikolic Maja Dordevic Ljubomir Stojanov 《Indian journal of clinical biochemistry : IJCB》2005,20(2):178-181
We propose a rapid, simple metodology for routine analysis of human urine to detect vanillylmandelic and homovanillic acid
related to neuroblastoma. The assay were specific capillary gas chromatography with flame ionization detection. In this methodology
an internal standard is used and the procedure involves ethyl ester formation without isolation of the compounds of interest.
The run time is 36 minutes. We also report quantitative results for urinary vanillylmandelic and homovanillic acid in neuroblastoma
patients, demonstrating the diagnostic value of this method. 相似文献
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银杏叶提取物（Gink Biloba Extract,GBE）是银杏干燥叶通过中药提取方法制成的提取物。文章分析了历年来相关GBE的提取和分离纯化方法,如常规提取法的水提取法,有机溶剂萃取法,树脂吸附分离法;新型提取法的超临界CO2萃取法,超声波提取法,高速逆流色谱法等以及GBE应用于牙膏的相关研究进展情况。 相似文献
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采用廉价的催化剂代替昂贵的金属,低成本的一氧化碳代替氢气乃至光气,一直是人们追求的目标.综述了非金属硒在含碳、氮、氧、硫类有机化合物中的催化羰基化反应,以及在Se/CO/H2 O体系中一些有机化合物的高选择性还原反应,介绍了近期的一些新进展.催化剂量的硒在温和条件下,即可活化一氧化碳而直接进行羰基化和还原反应,特别是发展了将硝基化合物的还原羰基化与胺的氧化羰基化相结合,合成一系列精细化学品和生物化学品.催化剂硒在催化反应中表现出反应过程相转移的特性,兼具了多相催化与均相催化的优点,是反应过程相转移概念中的典型实例.硒催化反应的特点是反应物转化率高,反应选择性专一,原子经济性高,对环境友好,且可部分替代光气合成法 相似文献
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S. V. Suresh Babu M. M. Shareef A. Pavan Kumar Shetty K. Taranath Shetty 《Indian journal of clinical biochemistry : IJCB》2002,17(2):7-26
Quantification of total and individual amino acids in biological fluids such as plasma, urine and cerebrospinal fluid has
an important diagnostic implication in laboratory medicine. The present paper describes protocols for the assay of total amino
acids by modified method based on dinitrophenyl and HPLC profile involving pre-column derivatization with o-pthalaldehyde
(OPA) derivatization, respectively. The method, based on the alkylation of-SH groups prior to OPA derivatization of amino
acids followed by reverse phase high performance liquid chromatography, provide a comprehensive profile of more than twenty
amino acids (including-SH group containing) in a single run lasting about 45 minutes. The present study, apart from establishing
the normal profile of amino acids in plasma of Indian sub population, also presents HPLC profile for some of the rare amino
acidopathies. 相似文献
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《Electronic Journal of Biotechnology》2014,17(6):329-333
BackgroundThe roots of chicory and the tubers of Jerusalem artichoke are used for the production of inulin. However, a quality of tubers and roots, i.e. the content of inulin, monosaccarides and disaccharides, depends on the activity of enzymes implicated in the metabolism of inulin. The knowledge on the changes of activities of inulin synthesizing and degrading enzymes is limited during plant sprouting, growth and dormancy. It happens due to complicated measurements of the product of enzymatic reaction in the presence of crude plant extract. Fructan exohydrolase (β-d-fructan fructohydrolase, FEH, EC 3.2.1.80) is an enzyme responsible for the hydrolysis of fructans in plants. For fructose as the reaction product measurement, a high-performance liquid chromatography is usually used. The aim of the study was to choose a simple and suitable method for FEH activity determination and the measurement of fructose in the presence of plant extracts.ResultsTwo chemical methods, i.e. copper(II)–neocuproine and 3,5-dinitrosalicylic acid, and the enzymatic one based on the reactions catalyzed by hexokinase, phosphoglucose isomerase and glucose-6-phosphate dehydrogenase were used. Enzymatic method was found to be suitable for FEH activity determination in plant extracts, and on the contrary to chemical methods no interference effects of compounds from crude plant extracts were observed.ConclusionEnzymatic method is applicable for the routine analysis and will allow performing the investigations without special equipment on the inulin degrading enzyme in biotechnologically important crops. 相似文献
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通常按照两个标准来评价印刷品的质量:一个是色彩的还原程度,另一个则是套印的精度。彩色制版是一个色彩的分解过程,而彩色印刷是一个色彩的组合过程,这个色彩的组合过程就叫套印。实现良好而准确的套印对于印出好的产品是非常的重要。套印准确的要求不仅仅局限于同一张印刷品上的不同色,而且同一印刷品的正背两面,同一批产品的印张之间都应当达到相应的标准。在实际印刷中容易导致套印不准的原因多种多样,其产生的原因也是各不相同。文章就套印精度对印品色彩再现的影响和双面印刷过程中较常见的影响套印精度的因素与应对进行简要的探究与分析。 相似文献
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For the estimation of copper, diethyldithiocarbamate method is most commonly employed in various laboratories where atomic
absorption spectrophotometer is not available. The prevalence rate of gastrointestinal malignancies is very high in Kashmir
as compared to other parts of the world. We could find high serum copper levels in gastrointestinal tract cancer. Intake of
salted tea, prepared in copper vessel, is very common in Kashmir. Such tea samples showed copper value as 3168.9 (S.D. 700.5)
μg/dl estimated by diethyldithiocarbamate method. When these samples analysed by atomic absorption spectrophotometer, the
copper levels were just 9% as reported by colorimetric method. Various black salted tea samples were prepared in the laboratory
in glass vessel. The mean copper was 1115.0 (S.D. 350.4) μg/dl. After addition of milk, the values were reduced by 50%. Nine
phenolic compounds showed varying amount of copper by colorimetric method and no copper could be detected by atomic absorption
spectrophotometer. Phenolic compounds present in tea leaves interfere in the estimation of copper by diethyldithiocarbamate
method. It is suggested that diethyldithiocarbamate colorimetric method for copper estimation is not suitable for solutions
containing phenolic compounds. 相似文献
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本文主要对生活饮用水中亚硝酸盐的检测方法进行了探讨,即采用离子色谱法检测亚硝酸盐。离子色谱法检测阴离子有几个有点：二、节省人力物力;二、省时;三、实现结果的迅速测定。 相似文献