贯众属10种植物染色体数目

对鳞毛蕨科Dryopteridaceae贯众属Cyrtomium Presl的10种植物的染色体数目进行报道。其中低头贯众C.nephrolepioides n=82,2n=164;单叶贯众C．hemionitis n=123,2n=c．123;惠水贯众C．grassum n=c．82,2n=164;披针贯众C．devexiscapulae 2n=164;小羽贯众C．lonchitoides 2n=82;大叶贯众C．macrophyllum 2n=164;云南贯众C．yunnanense n=123为首次报道。     

刺齿贯众及贯众配子体发育的培养观察

用腐叶土为基质培养刺齿贯众和贯众的孢子,在光学显微镜下观察其配子体的发育过程.结果表明.刺齿贯众和贯众的配子体发育特征极为相似:孢子均为单裂缝,具周壁,培养5～7 d后萌发;原丝体形态多样;35.d后发育为原叶体,心形,具毛状体;60 d后性器出现,多数为雌雄异株;85～90d后配子体发育出幼孢子体.     

山东贯众属（鳞毛蕨科）两新种

描述了山东贯众属两新种—密齿贯众 （Cyrtomium confertiserratum） 和倒鳞贯众 （C.reflexosquamatum）。植物形态学和孢粉学 （光学显微镜与扫描电镜） 观察结果显示：密齿贯众与贯众复合群中的原变型 （Cyrtomium fortunei f. fortunei） 相近似,区别在于本新种顶生羽片菱形,基部1~2深裂,裂片长3~4cm,宽约10mm,侧生羽片边缘有细密锯齿,囊群盖边缘有小齿,孢壁具不规则的瘤状纹饰。倒鳞贯众与山东贯众 （C.shandongense） 形态相近,但倒鳞贯众体型较大,高达60cm,羽片较多,达15~29对,叶轴基部以上密被倒生鳞片,孢壁为耳片状及网结状纹饰,易于区别。     

湖南省贯众属一新种

武陵贯众新种（图1）CyrtomiumwulingenseS.F.Wusp.nov.SpeciesarcteaffinisC.obliquumChingetshing,differtpinnislongioribus,ovato--triangularis,glabris;indusiisdenticulalo--serratis.'Planta20~35cmaha.Rhizomateerectocumstipitedensepaleaceo,paleisbrunneis,lanceol     

贯众的繁殖方法及栽培技术

介绍了用贯众根茎及孢子的繁殖方法,为扩大药源及开发利用提供参考.     

石灰岩地区蕨类植物低头贯众的配子体发育研究

采用原生境腐殖土对低头贯众[Cyrtomium nephrolepioides (Christ) Cop.]孢子进行培养,在显微镜下详细观察了其配子体发育的全过程.结果表明:低头贯众孢子深棕褐色,二面体形,极面观椭圆形,孢子萌发不具假根或为书带蕨型(Vittaria-type);丝状体由3～8个细胞构成;片状体上偏斜具毛状体,宽达10个细胞;原叶体的发育为叉蕨型(Asplenium-type).成熟的原叶体为对称心形,具乳头状毛状体,假根分叉,根尖膨大,精子器壁由3细胞构成和颈卵器弯曲等表现出进化的特征,但假根含有叶绿体又表现了原始的系统学特征.研究认为孢子萌发较慢,假根尖膨大和毛状体等似乎是该种配子体对石灰岩土壤特殊生境的适应对策.     

响应面法优化超声辅助提取贯众多酚工艺

利用响应面法优化贯众多酚的提取工艺。在单因素试验的基础上,选择超声时间、超声温度、料液比、乙醇浓度为自变量,贯众中多酚的提取率为响应值,进行Box-Benhnken中心组合实验设计,运用响应面法优化提取条件,得到最优提取条件如下:超声时间20 min,超声温度46℃,料液比1∶40,乙醇浓度35%,经验证,贯众中多酚的提取率为8.11660%,理论值为8.12986%,RSD为0.15%。该工艺高效、稳定,有一定的应用价值。     

贯众属的叶表皮特征

对贯众属（Cyrtomium）19种植物和近缘类群的15种植物的叶表皮形态特征进行了光学显微镜观察,并对包括贯众属3个亚系的模式种在内的12个种进行了扫描电镜观察。结果显示贯众属的叶表皮细胞为多边形或不规则形,垂周壁近平直、弓形、浅波状、波状至深波状。贯众属的气孔器分布于叶片下表皮,有无规则型、横列型和极附型三种类型,其中无规则型是主要的气孔器类型。气孔器表面观为宽椭圆形,长椭圆形,稀为近圆形,气孔外拱盖内缘近平滑、浅波状至啮齿-浅波状。大多数种类叶片表面角质膜具条纹,并常有条状隆起,或具颗粒等附属物。目前研究未发现可作为邢公侠二系四亚系诊断特征的明显的叶解剖特征。     

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.     

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     

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.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV