泽泻染色体的核型分析

对泽泻体细胞染色体计数,并对其核型进行分析,结果表明：泽泻的染色体数目为2n=14;核型公式为2n=2x=14=10m 4T,染色体相对长度组成为2n=14=2L 6M2 2M1 4S,属于2B型。全组染色体总长40．15μm,长臂总长为25．14μm,核型不对称系数为62.62％。染色体总体积为104．26μm^3。     

内葵杂3号染色体核型分析

对内蒙古地区的栽培品种内葵杂3号三交种和单交种了进行了核型分析。其结果为:内葵杂3号三交种和单交种的染色体数均为2n=34,各具一对随体染色体。三交种第2对染色体具随体且为近中部着丝粒染色体,其余为中部着丝粒染色体,染色体相对长度变异范围4.105%～7.703%,核型公式为2n=2x=34=32m+2sm(2sat),核型类型属于1A型;单交种均为中部着丝粒染色体,第4对染色体具随体,染色体相对长度变异范围3.661%～8.128%,其核型公式为:2n=2x=34=34m(2sat),核型类型属于1B型。     

异叶苣苔属(苦苣苔科)的核型研究

本文首次报道了中国特有异叶苣苔属的染色体数目及核型。该属所研究种类的染色体数目均为 2n＝18,染色体长度在2.0µm以上,在尖舌苣苔族所报道的染色体中显示出较原始的性状。尖舌苣苔 族的染色体基数可能是x=9。异叶苣苔属的间期核均为复杂型;前期染色体呈渐变型。核型从对称型 向不对称型的演化主要表现在近中部着丝粒,尤其是近端部着丝粒染色体比例的增大。毕节异叶苣苔 W．bljieensis和峨眉异叶苣苔W．tsiangiana var．wilsonii的核型分别为2n=2m＋8m＋8sm(1sat)和 2n=2m＋8m(1sat)＋8sm(2sat),较为对称。紫红异叶苣苔W．purpurascens和白花异叶苣苔W. tsiangiana var. tsiangiana的核型分别为2n=4m＋6sm＋8st(1sat)和2n=4m＋8sm(2sat)＋6st,比较 特化。河口异叶苣苔W．hekouensis的核型是2n=4m+10sm(1sat)+4st,处于二者之间。峨眉异叶苣 苔和原变种白花异叶苣苔的核型差异较大,在外部形态方面二者之间的性状变异也间断较大。本文建 议将该变种从白花异叶苣苔W．tsiangiana中移出自成一种,并和毕节异叶苣苔近缘。     

中国淡水三角涡虫(Dugesia sp)的染色体研究(Ⅰ)

利用空气干燥法对不同产地淡水三角涡虫的染色体进行了研究。核型分析表明：河南淇县鱼泉三角涡虫(Dugesia sp)和浙江杭州龙井三角涡虫(Dugesia sp)体细胞中有16条染色体,为二倍体,核型公式为2n=2x=16=16m,均为具中部着丝粒染色体;河南济源不老泉三角涡虫(Dugesia sp)有24条染色体,为三倍体,核型公式为2n=3x=24=24m,亦全部由中部着丝粒染色体组成。上述3个产地淡水三角涡虫染色体的形态较为接近。北京樱桃沟三角涡虫(Dugesia sp)的体细胞染色体数目为24,为三倍体,核型公式为2n=3x=24=22m 2sm,由中部和亚中部着丝粒染色体组成,其中第2、4号各有一条染色体属于亚中部着丝粒染色体。研究结果表明：4个产地三角涡虫的体细胞染色体数目存在较大差异,包括二倍体(2n=2x=16)和三倍体(2n=3x=24),染色体基数属于x=8类型。     

党参染色体核型分析

对党参细胞染色体进行了核型分析。研究表明,党参染色体数为2 n=16。染色体的核型为2n=12m 4 sm=16。第1、2、3、4、5、8对是中间着丝粒染色体(m);第6对和第7对染色体属于近中着丝点染色体,未观察到有携带随体的染色体存在。     

国产十五种翠雀族植物的核型研究

本文报道了国产乌头属Aconitum L.12种和翠雀属Delphinium L．3种植物的染色体数目和核型。花葶乌头A．scaposum var．scaposum和聚叶花葶乌头A．scaposum var．vaginatum的核型公式为2n=2m+6sm+8st;两色乌头A．alboviolaceum为2n＝16＝2m+6sm(2sat)十8st;高乌头A．sinomontanum var．sinomontanum为2n＝16＝4m+4sm+8st,而狭盔高乌头A．sinomontanum var．angustius为2n＝32＝6m+6sm+20st(1sat);褐紫乌头A.brunneum为2n＝16＝2m(1sat)+14sm 松潘乌头A．sungpanense为2n＝16＝6m(2sat)+10sm(2sat);弯枝乌头A．arcuatum为2n=16=4m+12sm;乌头A．carmichaeli为2n=32＝10m+22sm;北乌头A．kusnezoffii为2n＝32＝10m十22sm;鸭绿乌头A.jaluense为2n＝32=10m+22st;伏毛铁棒锤A．flavum为2n＝16＝2m+14sm; 铁棒锤A．pendulum为2n=16=4m+12sm;缩梗乌头A．sessiliflorum为2n＝16＝2m+10sm+4st;展毛翠雀花D．kamaoense var．glabrescens 为2n=16＝2m+6sm+8st;蓝翠雀花D．caeruleum为2n=16=2m+6sm+8st;多枝翠雀花D．maximowiczii为2n=16=2m+6sm+8st。其中花葶乌头、狭盔高乌头、褐紫乌头、松潘乌头、鸭绿乌头、伏毛铁棒锤、缩梗乌头、展毛翠雀花、蓝翠雀花、多枝翠雀花的染色体数目和核型为首次报道。     

当归属及近缘小属的核型演化及地理分布研究

本文报道了当归属Angelica及3个近缘小属12种植物的核型,其中10种为首次报道。带岭当归A．dailingensis 2n＝22＝20m+2sm(SAT);丽江当属A．likiangensis 2n＝22＝18m+4sm; 青海当归A．nitida 2n＝22＝14m+4sm+4sm(SAT);林当归A．silvestris 2n＝22＝16m+4sm(SAT)+2st(SAT);紫花前胡A．decursiva 2n=22＝16m+4sm+2sm(SAT);秦岭当归A．tsinlingensis 2n＝22＝18m+4sm; 阿坝当归A．apaensis 2n＝22＝14m+6sm+2st(SAT);隆萼当归A．oncosepala2n＝4x＝44＝28m+12sm+4st,三小叶当归A．ternata 2n=22＝10m+8sm(SAT)+4st(SAT);柳叶芹Czernaevialaevigata 2n=22＝14m+6sm+2sm(SAT);短茎古当归Archangelica brevicaulis 2n＝22＝8m+2m(SAT)+4sm+4sm(SAT)+4st;高山芹Coelopleurum saxatile 2n＝28＝12m+6sm+10st。除带岭当归核型为1A型和高山芹为2B型外,其余种类均为2A型。根据染色体长度比和平均臂比绘制了本次和我们过去已报道的当归属及近缘属23种植物的核型散点图。据核型类型和近端着丝点的有无,把当归属20个种的核型分3组。并结合外部形态、花粉类型和地理分布,探讨了各近缘属的系统演化关系。     

二倍体矮牵牛花粉母细胞异常减数分裂的观察与核型分析

以夏季高温时期二倍体矮牵牛花蕾为材料,采用常规制片法,对花粉母细胞异常减数分裂进行观察并选取终变期进行染色体核型分析。结果发现:异常减数分裂主要表现为具有多核仁、二价体提前分离成单价体、赤道板外的染色体,姊妹染色单体提前分离、不均等分离,落后和丢失染色体,具有微核的三分体和四分体,中期Ⅱ纺锤体定位发生异常出现融合纺锤体和八字形纺锤体可导致2n花粉产生;矮牵牛终变期核型公式为K(2n)=2x=14=10m+4sm(2SAT),其中第1、4、5、6、7号为中部着丝粒染色体,第2号(具有随体)、3号为亚中部着丝粒染色体,染色体相对长度组成为2n=14=4M_1+10M_2,核型分类为2A型。研究表明,矮牵牛异常减数分裂可导致2n花粉和不育花粉的产生,利用终变期进行核型分析具有材料丰富、二价体形态清晰不需人为配对分析等优点,为矮牵牛细胞学研究提供了新方法。     

黑藻属植物的核型分析

本文以根尖细胞为材料,观察了黑藻属Hydrilla植物的染色体核型。 它由两群染色体组成：1—5 为长染色体,6—8 为短染色体。 染色体基数x=8。轮叶黑藻Hydrilla verticillata(L. f.)Royle为二倍体;染色体数目为2n=2x=16; 雌雄之间既无染色体数目的差别,也无异型染色体存在;核型公式为2n=2x=16＝6m+6Sm十4St。 罗氏轮叶黑藻Hydrilla verticillata var．roxburgbii Casp系同源三倍体; 染色体数目为2n=3x=24; 核型公式为2n=3x=24=9m+9Sm+6St。     

葱属根茎组8种植物的染色体数目和核型报道

本文对国产葱属根茎组的8种植物进行了染色体研究,发现染色体数目2n＝16或32,核型属2A 或2B型,对称性较高。其染色体数目和核型分别为：Allium leucocephalum 2n(2x)＝16＝12m+2sm +2st(2SAT); A,strictum 2n(4x)＝32＝16m+4sm+12st;A.ramosum 2n(2x)＝16=14m+2st (2SAT); A．bidentatum 2n(4x)=32＝24m+4sm+4T;A．tenuissimum 2n(2x)=16=10m+4sm+ 2st(2SAT),A．anisopodium 2n(2x)＝16＝12m+2sm+2st(2SAT);A．anisopodium var．zimmermanni anum 2n(4x)＝32＝24m+4sm+4st(4SAT); A．condensatum 2n(2x)＝16＝14m+2st(2SAT)。多数种的染色体资料为国内首次报道。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.