云南“生态茶”的化学成分

从云南西双版纳产大叶茶（Ｃａｍｅｌｌｉａｓｉｎｅｎｓｉｓｖａｒ．ａｓｓａｍｉｃａ）制成的“生态茶”中分离到１１个化合物和１个混晶,经光谱测定,１１个化合物分别鉴定为没食子酸、（＋）儿茶素、（－）表儿茶素、（－）没食子儿茶素、（－）表没食子儿茶素、（－）表儿茶素－３－０没食子酸酯、（－）表没食子儿茶素－３－Ｏ没食子酸酯、茶素、１,４,６－三役食子酰基－β－Ｄ葡萄糖１－Ｏ－没食子酰基－４,６－（－）－六羟基联苯二甲醚基－β－Ｄ－葡萄糖以及咖啡因;混晶为芦丁和山奈酚－３－芸香糖甙的混合物。这是对国产大叶茶的第一次较详细的化学研究。     

栓皮栎虫瘿的酚性成分及其生物活性

从栓皮栎（Quercus variabilisBl.）虫瘿中分离了２对平衡互变异构体和４个单体化合物,通过光谱数据和化学方法鉴定：Ｇ－１为１－Ｏ（３′－没食子酰基）没食子酰基－β－Ｄ－葡萄吡喃糖和１－Ｏ－（４′－没食子酰基）没食子酰基－β－Ｄ－葡萄吡喃糖的平衡互变异构体,Ｇ－２为３－Ｏ－没食子酰基－没食子酸和４－Ｏ－没食子酰基－－没食子酸的平衡互变异构体,-3O一１,６－二－Ｏ没食子酰基－β－Ｄ－葡萄吡喃糖,Ｇ－４为１,２,３,６－四－Ｏ－没食子酰基－β－Ｄ－葡萄吡喃糖,Ｇ－５为１－Ｏ－没食子酰基－β－Ｄ－葡萄吡喃糖,Ｇ－６为没食子酸甲酯。对Ｇ－１、Ｇ－３和Ｇ－４进行初步的抗肿瘤、抗脂质过氧化和抗血小板聚集活性实验。     

日本续断中新五糖皂甙的结构及其核磁共振光谱

从日本续断（Ｄｉｐｓａｃｕｓ ｊａｐｏｎｉｃｕｓ Ｍｉｑ．）根的乙醇提取物中分得一个新的三萜皂甙,其结构被鉴定为３．－Ｏ－〖β－Ｄ－吡喃葡萄糖（１→）〗〖α－吡喃鼠李糖（１→３）〗－β－Ｄ－吡喃葡萄３９糖（１→３）－α－Ｌ吡喃鼠李糖（１→２）－α－吡喃阿拉伯糖－齐墩酸。采用一维ＳＥＭＤＹ谱和转坐标ＮＯＥ差谱核磁共振新技术相结合的方法,对糖体间和９糖体与甙元间的连接顺连接位置进行了研究。该方法的结果     

慈溪麦冬甙A和B的结构

从浙江慈溪产中药麦冬（Ｏｐｈｉｏｐｏｇｏｎ ｊａｐｏｎｉｃｕｍ）中分离得到２个新的Ｃ２７甾体甙－－慈溪麦冬甙Ａ（２）和Ｂ（３）以及已知甙ｏｐｈｉｏｇｅｎｉｎ３－氧－α－Ｌ－鼠李糖吡喃基（１→２）「β－Ｄ－木糖吡喃基（１→３）」－β－Ｄ－葡萄糖吡喃甙（２）和ｏｐｈｉｏｇｅｎｉｎ ３－氧－α－Ｌ－鼠李糖吡喃基（１→２）「β－Ｄ－木糖吡喃基（１→３）」「β－Ｄ－葡萄糖吡喃基（１→４）」－β－Ｄ－葡萄糖吡     

闭鞘姜根中的甾体皂甙

从闭鞘姜「Ｃｏｓｔｕｓ ｓｐｅｃｉｏｓｕｓ（Ｋｏｅｎｉｇ）Ｓｍｉｔｈ」根茎中分离出五个化合物。经波谱解析和化学降解,证明其化学结构分别为胡萝卜甙（Ａ）：薯芋皂甙元３－Ｏ－ａ－Ｌ鼠李吡喃糖基（１－２）－β－Ｄ－葡萄吡喃糖甙（Ｂ）;薯芋皂甙元３－Ｏ－ａ－Ｌ－鼠李吡喃糖基（１－２）「ａ－Ｌ－鼠李吡喃糖基（１－４）」β－Ｄ葡萄吡喃糖甙（Ｃ）;薯芋皂甙元－３－Ｏ－ａ－Ｌ－鼠李吡喃糖基（１－２）「β－Ｄ－葡萄     

印楝愈伤组织的化学成分

从印楝（Ａｚａｄｉｒａｃｈｔａ ｉｎｄｉｃａ Ａ．Ｊｕｓｓ）的愈伤组织中,共分离鉴定出５个化合物,经理化性质和波谱分析分别确定为：柳杉酚⑴,豆甾醇⑵,软酯酸－１－甘油酯⑶,豆甾醇－３－Ｏ－β－Ｄ－吡喃葡萄糖甙⑷,豆甾醇－３－Ｏ－β－Ｄ－吡喃葡萄糖甙－６’－十六烷酸酯⑸。     

麦冬的配糖体成分

从川麦冬（Ｏｐｈｉｏｐｏｇｏｎ ｊａｐｏｎｉｃｕｓ）根部乙醇提取物中分离得到四个已知化合物,经波谱分析确定其结构分别为：龙脑７－Ｏ－β－Ｄ－吡喃葡萄糖甙（１）,龙脑７－Ｏ－〔β－Ｄ－呋喃芹糖（１→６）〕－β－Ｄ吡喃葡萄糖甙（２）,４－烯丙基－１,２－苯本酚１－Ｏ－〔α－Ｌ－吡喃鼠李糖（１→６）〕－β－Ｄ－吡喃葡萄糖甙（３）,５－烯－１β,３β,１６β,２２Ｓ－胆甾四醇１－Ｏ－α－Ｌ－吡喃鼠李糖１６     

婆婆针的化学成分

婆婆针（ＢｉｄｅｎｓｂｉｐｉｎｎａｔａＬｉｎｎ）是具有清热解毒功能的民间药用植物,从婆婆针的地上部分分离鉴定了３个苯丙素甙类化合物,４－Ｏ－（６″－Ｏ－对香豆酰基－β－吡喃葡萄糖）－对－香豆酸（１）,４－Ｏ－（２″－Ｏ－乙酰基－６″－Ｏ－对－香豆酰基－β－Ｄ－吡喃葡萄糖）－对－香豆酸（２）及４－Ｏ－（２″,４″－Ｏ－二乙酰基－６″－Ｏ－对－香豆酰基－β－Ｄ－吡喃葡萄糖）－对－香豆酸（３）,其中（３     

头序Song木化学成分研究

自头序Ｓｏｎｇ木７０％ＥｔＯＨ提取物分得６个化合物,应用光谱技术（ＩＲ,ＭＳ,ＨＮＭＲ,＾１３ＣＮＭＲ,ＤＥＰＴ,２ＤＮＭＲ）及化学方法,确定了他们的结构,分别为β－谷甾醇（Ⅰ）,胡萝卜甙（Ⅱ）,齐墩果酸（Ⅲ）,竹节参皂甙１（Ⅳ）,竹节参皂甙Ⅳａ（ＣｈｉｋｕｓｅｔｓｕｓａｐｏｍｉｎⅣａ）（Ⅴ）,常春藤皂甙元－２８－Ｏ－β－吡喃葡萄糖醛酸（１→４）－β－Ｄ－吡喃葡萄糖甙（Ⅵ）,以上化合物均为首次从该     

圆果雪胆中的皂甙成分

从圆果雪胆（Ｈｅｍｓｌｅｙａ ａｍａｂｉｌｉｓ）的块茎中分离到１０个化合物,其中３个雪胆皂甙是首次从该种植物中得到,它们的结构通过光谱和化学的方法鉴定为齐墩果酸－３－Ｏ－α－吡喃阿拉伯糖（１→３）－β－葡萄糖醛酸甙,２８－Ｏ－β－Ｄ－吡喃葡萄糖齐墩果酸３－Ｏ－α－吡喃阿拉伯糖（１→３）－β－Ｄ－葡萄糖醛酸,２８－Ｏ－β－Ｄ－吡喃葡萄糖齐墩果酸３－Ｏ－「β－Ｄ－吡喃葡萄糖（１→２）」－「α－吡喃阿     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.     

Composition and diversity of bird communities in Swedish farmland–forest mosaic landscapes

CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden.

Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden.

Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified.

Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds.

Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed.     

Chemical constituents from the fruits of Rhus typhina L. and their chemotaxonomic significance

This work describes the isolation and characterization of twenty-nine compounds from the fruits of Rhus typhina L., including eleven flavonoids (1–11), eleven phenols (12–22), two pentacyclic triterpenes (23–24), two organic acids (25–26), one lumichrome (27), one courmarin (28) and one pyrimidine (29) on the basis of their spectroscopic data. Compounds apigenin (1), daidzein (4), orobol (5), 3′, 5, 5′, 7-tetrahydroxyflavanone (6), naringenin (7), butein (8), (-)-catechin (9), quercetin-3-O-α-L-(3″-O-galloyl)-rhamnoside (11), 2-hydroxybenzoic acid (13), 4-hydroxybenzaldehyde (14), vanillin (15), methyl 3,4-dihydroxybenzoate (16), 3,5-dihydroxybenzamide (18), tyrosol (19), caffeic acid (20), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (21), phlorizin (22), friedelin (23), oleanolic acid (24), 4,4-dimethyl-heptanedioic acid (25), anthranilic acid (26), lumichrome (27), scoparone (28) and uracil (29) have not been recorded before in this plant. This is the first report on the occurrence of compounds 4–7, 9, 11, 13–14, 16, 18–21, 25–29 from the genus Rhus. Moreover, the chemotaxonomic significance of these isolated compounds was also summarized.