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Inthemoleculardesignofpesticides"SubstructureLinkWay"playsanimportantroleininventingnewkindofleadcompounds.Wehavefoundthatbenzisothiazoleisthebioisosterismofsulfonylureaherbicides(suchasDPX-T6376)'.IthasbeenreportedthatacylureaderivativeswithmultisubstitUtedpyrimidineringhadpotentbiologicaIactivity".Inordertosearchfornewkindofmedicineswithexcellentefficiency,lowerpoisonandlessside-effect,wedevisedandsynthesizedfourteena-chloroacetylureascontaining4,5,6-trisubstitutedpyrimidinring5a~nanduse… 相似文献
994.
1 INTRODUCTIONAbscisicacid(ABA)isoneofplanthormoneswhichwasisolatedfromyoungcottonfruitsin1963[1].Itnotonlyinhibitsplantgrowth,butalsoprotectsplantsa-gainstdeprivationofwaterduringdroughtdays[2].Hydroxyalkylphosphonicacidsandtheirderivativesappeartobeveryimportantfortheirwidebiologicalactivitiesintheinhibitionofenzymes,fungicidesandplantgrowthregulation[3].Wedesignedandsynthesizedthetitlecompound4,theunsaturatedphosphonateanaloguesofABA,whichexhibitsplantinhibitoryactivityontheelongati… 相似文献
995.
Milena Polumackanycz Mateusz Kaszuba Agnieszka Konopacka Urszula Marzec-Wrblewska Marek Wesolowski Krzysztof Waleron Adam Buciski Agnieszka Viapiana 《Molecules (Basel, Switzerland)》2020,25(22)
Rosa canina L. (dog rose) is a rich source of phenolic compounds that offer great hope for the prevention of chronic human diseases. Herein, wild and commercial samples of dog rose were chemically characterized with respect to their phenolic composition by liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI/MS). Furthermore, in vitro antioxidant properties and antibacterial activity of dog rose fruits and leaves hydromethanolic extracts and infusions were also evaluated. The results revealed that wild and commercial fruits of dog rose are similar in terms of l(+)-ascorbic acid, total phenolics (TPC), total flavonoids (TFC) and total phenolic acids (TPAC) content, individual phenolic constituents and antioxidant activity. Moreover, the fruits had lower levels of phenolic compounds and also revealed lower biological activity than the leaves. On the other hands, the highest content of TPC, TFC, TPAC, individual phenolic constituents, DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activity and FRAP (ferric reducing antioxidant power) were found in the leaf’s infusions. They were also the only ones to show antibacterial activity. Overall, these finding confirmed usefulness of R. canina L. leaves and fruits as a rich source of bioactive phenolic compounds with potential use in food, pharmaceutical, and cosmetic industries. 相似文献
996.
The molecular anvil model of an enzyme taking into consideration the flexibility of enzyme molecules
Kazuo Amaya 《Journal of inclusion phenomena and macrocyclic chemistry》1987,5(4):535-544
The concept of a molecular anvil model of an enzyme, assuming a rigid enzyme molecule, is introduced. Two distinct features of enzymes, high catalytic power and high specificity, are reasonably and consistently explained. The dynamic nature of molecular anvil action is stressed. The origin of the high catalytic power is the spontaneous creation of a high energy state at the anvil site. The origin of the high specificity is a high sensitivity of the maximum accessible potential energy to the relatively extruded distance of the molecular anvil. The flexible model is developed by assuming a flexible enzyme molecule. It is deduced from this flexible model that enzyme activity shows a maximum with a wide range of monotonous change of the configuration of the enzyme molecule. This is the origin of the general property of enzymes that enzyme activity shows a maximum with monotonous variation of environmental parameters such as pH, temperature, pressure or some times concentration of chemical substances. The induced fit theory of Koshland is reasonably explained. The relation and differences between individual theories of enzymes are discussed. The enzymological basis of the complex regulation of biological organisms is discussed. The inversion of the sign of control of effectors is predicted when environmental parameters are varied. This concept may be useful in designing artificial enzymes or high specificity catalysts.Presented at the Fourth International Symposium on Inclusion Phenomena and the Third International Symposium on Cyclodextrins, Lancaster, U.K., 20–25 July 1986. 相似文献
997.
锂的生物必需性及人体健康效应 总被引:7,自引:1,他引:7
秦俊法 《广东微量元素科学》2000,7(3):1-16
综述了锂的生物必需性及人体健康效应。锂是有效的情绪稳定剂,随着新的情绪稳定剂的出现,对锂治疗的兴趣和研究虽已减少,但锂仍是治疗急性躁狂症和躁狂-抑郁病预防性管理的最有效措施,许多研究证明,锂对动物和人具有必需功能或有益作用。动物缺锂可导致寿命缩短、生殖异常、行为改变及其落空 类流行病学研究显示,饮水锂浓度与精神病住院率、杀人、自杀、抢劫、暴力犯罪和毒口犯罪率呈显著负相关。毒品 营养性锂补充研究院率 相似文献
998.
铷的生物必需性及人体健康效应 总被引:3,自引:0,他引:3
秦俊法 《广东微量元素科学》2000,7(8):1-18
综述了铷的生物必需性及其对人体的健康效应,包括:铷的生物学研究简史,铷的营养必需性,铷的生理功能和生物学作用,人体的铷摄入量。参考文献45篇。 相似文献
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1000.
近二十年来,高分辨率 27Al核磁共振( 27Al NMR)广泛应用于研究 Al?离子水解过程 ,Al?与环境生物配体的配位化学 ,环境与生物样品中铝含量测定和形态分析 ,监测铝在植物、动物、酵母菌等微生物中的转运过程 ,具有快速、直接、非破坏性等优点。 27Al NMR不仅适用于高浓度的溶液,也可应用于低浓度 (10- 6mol· L- 1)的实际环境、生物样品。应用 27Al MAS NMR可直接对固态样品中铝的存在状态和含量进行表征和测量。本文中对 27Al NMR的应用进展作一评述,并总结了近二十年来文献发表的 27Al化学位移数据。引用文献 70余篇。 相似文献