天然大环二芳基庚烷类化合物的研究概况

本文对目前已经发现的天然大环二芳基庚烷类化合物在植物中的分布及结构特征、生物合成和药理学研究进展进行了综述.     

二芳基喹啉类化合物抗结核效果及安全性

【背景】贝达喹啉作为治疗结核病的一种特效药,二芳基喹啉是以喹啉为骨架合成的一类化合物,但对于其在抗结核方面的研究鲜有报道。【目的】探究二芳基喹啉类化合物H2对结核分枝杆菌的抑菌效果和药物安全性,为药物研发奠定基础。【方法】采用比例法测定H2对不同结核分枝杆菌的最低抑菌浓度(minimum inhibitory concentration,MIC)和最小杀菌浓度(minimum bactericidal concentration,MBC),并选一线抗结核药物(异烟肼、利福平、乙胺丁醇)作为阳性对照,4周后观察结果;选昆明小鼠40只,分5个剂量组,灌胃给药,观察小鼠不同剂量下的存活状态及外观体征变化;根据LD50剂量,采用7d喂养实验,设3个剂量组(高、中、低)和空白对照组。实验结束,采取外周血并剖检,取各脏器称重,制作切片,观察病理改变。【结果】体外抑菌实验显示,H2对H37Rv的MIC与INH较相似,对耐药菌株仍有较好的抑菌效果;体内毒性试验显示,小鼠LD50为582.77 mg/kg。与空白组相比,高剂量组体质量在第5天差异极显著(P0.01),第6、7天差异显著(P0.05),红细胞计数、血小板和血小板比容差异显著(P0.05),肝脏系数差异极显著(P0.01)。镜下所见,剂量组肾脏组织有轻度炎症和水肿,肾小管上皮有轻度的水泡样变性,肝脏存在轻度的水肿和肝细胞的坏死。【结论】该化合物对不同结核分枝杆菌有较好的抑菌效果,有进一步开发、优化的意义。     

莽草酸芳构化制备二芳基胺类化合物

以莽草酸为起始物,经酯化及IBX氧化制备得到3-脱氢莽草酸甲酯。在甲醇溶剂中及对甲苯磺酸的催化下,3-脱氢莽草酸甲酯与芳香伯胺类化合物发生缩合-脱水芳构化反应,制备得到一类二芳基胺类化合物,即3-芳胺基-4-羟基苯甲酸甲酯类化合物。该方法以廉价的可再生资源为起始物,具有操作简单、条件温和、收率高等优点,是制备二芳基胺类化合物的一种有效途径。     

1，5-二芳基戊烷类化合物生物活性与结构关系的研究进展

本文对目前已经发现的天然1,5-二芳基戊烷类化合物在植物中的分布、结构特征、生物合成及其改构化合物的结构和生物活性作一简要综述.     

罗平产生姜的化学成分

从生姜(Zingiber officinaleRosc.)的根茎中分离得一个骨架新颖的天然产物,经波谱鉴定为一个新的生姜内酯(1),同时分离得到7个已知化合物,分别为6-姜烯酚(2),1-去氢姜二酮(3),6-姜磺酸(4),3,5-二酮-1,7-二-{(3-甲氧基-4-羟基)-苯基}-庚烷(5),姜酮A(6),β-谷甾醇(7)和豆甾醇(8)。     

肉豆蔻中二芳基丙烷类抗炎活性成分

本文报道了肉豆蔻果实乙酸乙酯部位的二芳基丙烷类化学成分及其抗炎活性.运用硅胶、反相RP-18材料和Sephadex LH-20凝胶等色谱技术共分离了5个二芳基丙烷类化合物.通过一维和二维核磁、高分辨质谱等波谱技术和文献数据对比将其结构分别鉴定为1-(3',4'-dihydroxyphenyl)-3-(4"-methox...     

天然二氢查尔酮类化合物分布及生物活性研究进展

综述了天然二氢查尔酮在植物中的分布情况及在降血糖、抗肿瘤、保肝等方面的生物活性,为二氢查尔酮类化合物的资源开发和在医药、食品领域的应用提供借鉴。     

植物源二萜类化合物微生物合成研究进展

植物源二萜类天然产物结构复杂且功能多样,具有抗癌、抗炎和抗菌等多种药理活性,在药品、化妆品和食品添加剂等方面广泛应用。近年来,基于植物源二萜类化合物(diterpenoids)生物合成途径中功能基因的逐步揭示和合成生物技术的发展,科研人员采用代谢工程技术构建了多种二萜类化合物的微生物细胞工厂,且多个化合物达到克级产量。本文对植物源二萜类化合物微生物细胞工厂的构建情况进行综述,介绍并探讨植物源二萜类化合物微生物合成的研究进展和改造策略,为高产二萜类化合物细胞工厂构建和工业化生产提供参考。     

植物病原真菌对二甲酰亚胺类杀菌剂的抗性分子机制

综述了近年来国内外植物病原真菌对二甲酰亚胺类杀菌剂抗性机制研究的主要成果,包括：二甲酰亚胺类杀菌剂（DCFs）的杀菌机制、植物病原菌对DCFs抗药性的产生现状、促分裂原活化蛋白激酶（MAPK）途径和依赖环化腺苷酸（cAMP）的蛋白激酶途径在抗药性产生中的可能作用及相关的分子生物学研究进展。     

植物(口山)酮甙类化合物

本文对目前已发现的天然产(口山)酮甙类化合物及其主要植物来源进行了综述,重点介绍了(口山)酮碳甙和氧甙的结构特点,同时介绍了它们在植物界的分布情况以及提取分离方法和药理学研究进展。     

甲型流感病毒自然温度敏感株的宿主依赖性

用鸡胚细胞(CEC)和Madin-Darby Canine Kidney(MDCK)两个宿主细胞系统,检查甲型流感病毒各亚型不同时期流行株的温度敏感性状(ts),发现自然界存在许多宿主依赖的温度敏感性突变株(hd-ts)。它们在CEC上是ts,在MDCK上却是ts~ 。检出的hd-ts株中有些曾经过人体接种观察证明为减毒株。这表明在CEC中鉴定的ts表型与对人减毒性状密切相关。     

THE BIOCHEMICAL ROLE OF NATURALLY OCCURRING POLYAMINES IN NUCLEIC ACID SYNTHESIS

1. The polyamines, putrescine, spermidine and spermine occur in free or acetylated form in a wide variety of living organisms. Putrescine is biosynthesized from ornithine or arginine; spermidine and spermine from methionine and either ornithine or arginine. 2. It is difficult to determine the intracellular distribution of polyamines since they are all very soluble in water and they are readily redistributed when cells are disrupted. Evidence suggests that a substantial proportion of the intracellular polyamines is attached to the ribosomes and that spermidine is not concentrated in the nucleus. 3. Polyamines bind strongly to both DNA and RNA. The strength of binding is:spermine > spermidine > putrescine. Polyamines stabilize the double helix of DNA, probably by forming a bridge across the narrow groove, by involving electrostatic bonding with the phosphate group. However, they do not appear to alter the overall conformation of DNA. Spermine enables single-stranded RNA to fold into a more compact configuration which is less susceptible to attack by ribonuclease. 4. Spermine and spermidine are able to stimulate the DNA primed RNA polymerase. They facilitate the removal of RNA from the DNA-RNA-enzyme complex. 5. Polyamines promote the association of ribosomal subunits and also the binding of amino acyl transfer RNA to ribosomes. They cause increased coding ambiguities in the process of translation in certain bacterial systems. 6. There is a close correlation between the intracellular concentration of spermidine and the rate of RNA synthesis both in rat liver and in Escherichia coli. Conditions which affect the rate of RNA synthesis also affect the concentration of free intracellular spermidine. 7. Bacteria usually contain putrescine and spermidine, whereas animal tissues contain spermine and spermidine. Spermidine probably fulfils the same role in both bacteria and animal tissues, but the presence of spermine, which is common to eucaryotes, is possibly associated with their more complex mechanisms for regulating RNA and protein synthesis.     

MATE CHOICE BASED UPON NATURALLY OCCURRING COLOR-PATTERN VARIATION IN A GUPPY POPULATION

This study tested the effect of differences in the extent of orange pigment in the color pattern of male guppies on the sexual responsiveness of females. Fish used in this study were descendants of a single natural population from the Paria River of Trinidad. Males from this population have unusually large, brilliant orange spots. I used three experimental approaches to test for discrimination by females among males based on the relative area of orange in color patterns: 1) the time to mating when a male was presented to a virgin female; 2) the frequency of sexual responses of females to passing, nondisplaying males; and 3) the proportion of a male's courtship displays that elicited a female sexual response. In all three experiments, females appeared to discriminate against males with less-than-average amounts of orange in their color patterns. In at least one experiment, however, the increase in female responsiveness with increasing amounts of orange leveled off and possibly decreased at high levels of orangeness. This suggests that there may be no advantage of increased amounts of orange above a certain level. These results suggest that female choice is a mechanism for the evolution of color patterns in guppies and may have contributed to the distinctive color pattern of the Paria population.     

A NATURALLY OCCURRING DEVELOPMENTAL SYNERGISM BETWEEN THE CELLULAR SLIME MOLD,DICTYOSTELIUM MUCOROIDES AND THE FUNGUS,MUCOR HIEMALIS

We here report the second record of a developmentally aberrant strain of a cellular slime mold from natural populations and demonstrate that this Dictyostelium mucoroides variant is capable of undergoing normal morphogenesis in the presence of the phycomycete fungus, Mucor hiemalis. The synergism is induced by an extracellular product(s) which is diffusable through thin agar membranes and is released by the fungus. The presence of the fungus not only induces stalk formation in this stalkless variant, but also increases the rate of sorocarp formation in 3 of 5 additional species of cellular slime molds assayed.