中国微桥蟌属研究(蜻蜓目,原蟌科)

记述中国的微桥蟌属9种,描述了其中1新种:福建微桥蟌Prodasineura fujianensis sp.nov..正模♂,福建省邵武市,2004-07-15,徐奇涵采.副模:2♂♂,2♀♀,福建省邵武市,2004-07-15,徐奇涵采.模式标本存放在漳州教育学院生物标本室.文中附有该属在我国的种检索表.     

中国红蟌属研究及新种记述（蜻蜓目,蟌科）

系统记述了红蟌属Pyrrhosoma Charpentier的研究历史,明确了本属的属征,描述了中国的种类,并确定一个采自中国云南省的新种Pyrrhosoma latiloba sp.nov.,模式标本保存于南开大学生命科学学院昆虫学研究所昆虫标本室。     

黄纹长腹扇蟌胸部色斑变异研究

不同种群的雄性黄纹长腹扇蟌胸部色斑存在较大的变异,主要表现在前胸背板斑纹的有无、合胸背面及侧面斑纹的面积大小、形状及数量等方面。本文通过几何形态学方法,以及对前胸背板斑纹的观察比较,对34个地里样点共319头雄性黄纹长腹扇蟌的胸部斑纹变异情况进行分析。几何形态学分析显示,依据合胸斑纹轮廓形状可将黄纹长腹扇蟌划分为东南(Southeast)与西北(Northwest)两群组,且在分布重叠区的种群中同时存在两种特征的个体;对前胸背板斑纹的观察统计显示,几乎所有分布于西北群组的样本前胸背板具一对蓝色斑纹,而东南群组的样本几乎都缺失这对斑纹。本研究使用的两方面证据所揭示的变异趋势相吻合,均证明雄性黄纹长腹扇蟌胸部斑纹随地理分布存在明显的变异规律。研究结果显示雄性黄纹长腹扇蟌胸部斑纹存在明显变异多样性,几何形态学可用于蜻蜓目昆虫色斑变异规律的研究,也为该物种的演化与地理格局的形成等后续研究提供证据支持。     

五种色蟌Cyt b基因序列及其系统发育关系

以昆虫mtDNA的Cytb基因作为分子遗传标记,用其特异性引物进行PCR扩增及DNA测序,共获得蜻蜓目束翅亚目色蟌科4属5种及1外群的Cytb基因部分序列(576bp),该片段中碱基T,C,A,G的平均含量分别为31.6,21.6,31.4和15.4%,A+T平均含量为63%,明显高于G+C含量(37%)。密码子第3位点的A+T平均含量较高,为66.4%。碱基替换多发生在密码子的第3位点。以巨齿尾溪蟌Bayadera melanopteryx作为外群构建系统发育树,结果显示,绿色蟌属Mnais和单脉色蟌属Matrona是单系群,绿色蟌属是单脉色属、细色蟌属Vestalis及艳色蟌属Neurobasis的姐妹群,是较早分化出来的一个类群。     

中国第一种走向世界的蜻蜓——华艳色蟌

早在270多年前，著名的生物分类学之父——瑞典的科学家林奈在他的《自然系统》中就收录了华艳色蟌,这是中国第一种走向世界的蜻蜓。也由于华艳色蟌特有的艳丽，吸引着许多喜爱和研究蜻蜓的外国人到中国来采集研究蜻蜓，以致许多中国蜻蜓都是由外国人命名，其模式标本也保存在外国的实验室。这既是我们的骄傲也是面对历史的无奈。     

北京地区均翅亚目昆虫的生态分布

调查发现北京地区现分布蜻蜓目均翅亚目昆虫 3科 1 0种 ,其中科的蓝纹与二色异痣为优势种 ,分布最为广泛 ,通过主成分分析 ,湿地内的浮水层植物盖度、挺水层植物盖度、周围植被盖度及沉水层植物盖度是影响它们分布的最主要生态因子 ,各因子的贡献率分别为 3 0 49,2 4 1 4,1 7 45和1 5 2 6%。色科黑色和透顶单脉色主要分布于北京西南部地区及北部山区水流较快、水体较浅、污染度较小的水域。长叶异痣、七条和白扇主要分布在河流和水库湖泊的边缘地带 ,数量相对较少。烟翅绿色、红痣绿色及白狭扇仅在山区发现 ,分布范围较为狭窄。     

黄蟌属(蜻蜓目:均翅亚目)稚虫形态分类特征稳定性研究

基于线粒体基因COI、核基因ITS序列数据,结合成虫、稚虫相互匹配的方法,文章对蜻蜓目广布种长尾黄蟌Ceriagrion fallax Ris和翠胸黄蟌Ceriagrion auranticum Fraser稚虫的尾鳃和上颚这两个传统的形态鉴定特征的稳定性进行了分析,结果显示:(1)长尾黄蟌稚虫尾鳃黑斑的有无、数量、颜色等特征均不稳定,且与种群、性别无关;(2)两种稚虫的上颚齿式特征在同种群内也呈现明显的不稳定性。因此,两种稚虫的尾鳃和上颚特征不稳定,鉴定时应慎用。这暗示蜻蜓目其他物种的形态特征或存在类似的不稳定性。     

光温条件对狭翅大刀螳生长发育的影响及其捕食功能研究

室内条件下饲养狭翅大刀螳(Tenodera angustipennis),研究温度与光照两个因子对狭翅大刀螳生长发育的影响。同时考察狭翅大刀螳若虫对不同密度小菜蛾幼虫与成虫及萝卜蚜的捕食功能反应．结果表明。温度对狭翅大刀螳生长发育的影响显著,随着温度的升高。在设定的温度范围内其历期明显缩短．狭翅大刀螳1～3龄若虫最适生长温度为25℃。而4、5龄若虫的最适生长温度为25～30℃．单因子光照对狭翅大刀螳生长发育无显著影响．捕食功能反应试验所得的数据,按HoUing模型进行模拟,经卡方检验。其理论值与实测值无显著差异。证明建立的模型能较好地模拟狭翅大刀螳的捕食情况．     

中国狭腹叶蜂属系统分类研究(膜翅目,叶蜂科)

厘订了中国狭腹叶蜂属种类,共报道14种,其中包括4新种:黄氏狭腹叶蜂Athlophorus huangae Wei et Nie,sp. nov.,亮翅狭腹叶蜂Athlophorus hyalopterus Wei et Nie,sp.nov.,烟翅狭腹叶蜂Athlophorus infuscatus Wei,sp.nov.,汪氏狭腹叶蜂Athlophorus wangae Nie et Wei,sp nov.,以及4个中国新纪录种:斑头狭腹叶蜂Athlophorus pilifrons(Cameron),黄褐狭腹叶蜂Athlophorus caprae Forsius,长斑狭腹叶蜂Athlophorus mimicarius Malaise和黑唇狭腹叶蜂Athlophorus gracilis(Konow).编制了中国种类检索表,新种模式标本分别保存于中南林学院昆虫标本室和中国科学院动物研究所.     

内蒙古草原三种植物群落中狭翅雏蝗造成的牧草损失(英文)

狭翅雏蝗Chorthippus dubius是我国北方草原的重要蝗种之一,在大发生年对牧草的威胁很大。它对牧草的损失至今尚无较准确的定量估算。本文通过测定不同发育阶段狭翅雏蝗的取食率、掉落毁损率,结合野外自然种群数据,对内蒙古草原三种植物群落中狭翅雏蝗造成的牧草损失进行了估测,并对三种草场蝗虫的经济阈值进行了计算。主要研究结果如下: 1.狭翅雏蝗对羊草、冷蒿、大针茅的取食率相似;取食率与虫体体重存在显著的线性相关。 2.狭翅雏蝗每个个体在一生中平均造成牧草损失487.55—784.4mg(干重),每日消耗与浪费的牧草为7.64—11.45mg。 3.狭翅雏蝗种群造成的牧草损失在冷蒿群落、羊草-大针茅-羊草群落、羊草-大针茅群落分别为1.52,1.65,0.76g/m,占地上初级生产量的2.96％、1.18％、0.42％,表现为越退化的草场,狭翅雏蝗对牧草的压力越大。其累积损失量的季节程式可以刚logisuc方程拟合。 4.狭翅雏蝗的经济阈值在羊草、羊草+大针茅+冰草、冷蒿草原分别为每平方米18.5、19.4、11.8头四龄为主个体。     

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.