甘肃萱草属植物的核型研究

本文研究了甘肃萱草属6种、1变种的染色体核型;黄花菜K(2n)=22=12m+10sm(2SAT);小黄花菜K(2n)=22=10m+12sm;北萱草K(2n)=22=8m+14sm;北黄花菜K(2n)=22=14m+6sm+2st;萱草K(2n)=22=12m+8sm+2st;重瓣萱草K(2n)=33=18m+12sm+3st:折叶萱草K(2n)=22=10m+10sm+2st。以上核型可自然地分成两大类群,第一类群包括小黄花菜、北萱草、黄花菜;第二类群包括折叶萱草、萱草、重瓣萱草、北黄花菜。     

大苞萱草染色体的核型分析

对大苞萱草体细胞染色体计数,并对其核型进行分析,结果表明:大苞萱草的染色体数目为 2n=22;核型公式为2n=2x=22=10m 6sm 4st 2T,染色体相对长度组成为2n=22=4L 6M2 10M1 2S, 属于2A型。全组染色体总长31．26μm,长臂总长为21．05μm,核型不对称系数为67．34％。     

萱草属中国特有种的细胞分类研究

对萱草属3个中国特有种,折叶萱草、西南萱草和多花萱草间的亲缘关系,不同学者有不同观点。本文试图从核型特征阐明三者的亲缘关系。折叶萱草、西南萱草和多花萱草的核型公式分别为：2n=12m+8sm+2T;2n=8m+12sm+2T和2n=12m+4sm+4st+2T。核型不对称性依次加大;三者均在T型(第11号)染色体着丝点端具有微小随体。三者染色体组分之间的欧氏距离：折叶萱草与西南萱草为0．2728;折叶萱草与多花萱草为0．4501;西南萱草与多花萱草为0.5741。以上资料表明,折叶萱草与西南萱草更为近缘,而多花萱草比前二者进化。     

黄精属5种植物的核型研究

本文报道了安徽省黄精属Polygonatum Mill．5种植物的染色体数目和核型。玉竹P. odoratum (Mill.)Druce黄山材料2n=16=10m(3sc)+6sm,滁县琅琊山材料2n=18=10m(1sc) +2sm+6st(2sc),二者均属2B核型． 长梗黄精P．filipes Mirr. 黄山材料2n=22=8m+8sm(2sc)+6st,属3B核型,安徽繁昌材料2n=14=10m+4sm和2n=16=8m +4sm+4st,二者均属2B核型。多花黄精(P.cyrtonema Hua)安徽黄山材料2n=20=8m+6sm+6st和2n=22=6m+8sm +4st+4t,二者均属3B核型,安徽滁县琅琊山材料2n=18=8m(2sc)+6sm+4st,属2B核型。长苞黄精(P．desoulayi kom．) 2n=22=10m(2sc)+6sm(1sc)+6st,属3B核型;轮叶黄精(P．verticillatum(L．)All．)2n=18=2m+2sm+10st+2t+2T和2n=24=6m+4sm+12st+2T,二者均属3B核型。其中玉竹2n=16,长梗黄精2n=14和2n=22,长苞黄精2n=22,轮叶黄精2n=18的染色体数目和核型均为首次报道。     

八个四倍体鹅观草属物种的核型研究

对8个鹅观草属物种的核型进行了研究。核型公式如下:纤穗鹅观草2n=4x=28=20m+8sm(2sat);紫穗鹅观草2n=4x=28=22m(2sat)+6sm;假花鳞草2n=4x=28=24m(2sat)+4sm;肃草2n=4x=28=22m+6sm(2sat);小颖鹅观草2n=4x=28=22m+6sm(2sat);纤瘦鹅观草2n=4x=28=24m(4sat)+4sm;变颖鹅观草2n=4x=28=20m+8sm(2sat);毛花鹅观草2n=4x=28=24m(2sat)+4sm。它们的核型属1A或2A型。其中后5个物种的核型为首次报道。     

对苞萱草的核型研究

本文报道用光学显微镜观察对苞萱草Ｈｅｍｅｒｏｃａｌｉｓｆｕｌｖａ（Ｌ．）Ｌ．ｖａｒ．ｏｐ ｐｏｓｉｔｉｂｒａｃｔｅａｔａＨ．ＫｏｎｇｅｔＣ．Ｊ．Ｗａｎｇ,ｖａｒ．ｎｏｖ．的染色体,按全国第一次植物染色体学术讨论会建议的标准进行核型分析。研究结果表明,对苞萱草体细胞染色体数目２ｎ＝２２,核型公式ｋ（２ｎ）＝２２＝１２ｍ＋６ｓｍ＋４ｓｔ,属于Ｓｔｅｂｂｉｎｓ核型的２Ｂ型。甘肃萱草属植物的核型可分为两大类群,对苞萱草的核型属于第二类群。对苞萱草与萱草Ｈ．ｆｕｌｖａ（Ｌ．）Ｌ．的核型较接近,为新变种的确立提供了细胞学方面的依据。     

中国毛茛属新分类群及其核型

新种R．shuichengensis L,Liao有两种核型类型,即基本型2n=2x=16=4m+2sm+10st(2SAT);杂合型2n=2x=16=4m+2sm+9st(1SAT)+1t(1SAT),其核型和近缘种R．trigonus Hand．- Mazz.核型相似,但其随体染色体短臂比后者更小而不同。新变种R．silerifolius var．dolicanthus L. Liao核型(2n=2x=16=4m+2sm+10st(2SAT)与原变种Var．silerifolius不同。根据形态和染色体的特征,我们认为本文中两个新分类群和R．Trigonus是国产毛茛组中x=8至x=7的过渡类群。     

辽宁地区产6种乌头(Aconitum)的细胞分类学研究

对我国辽宁地区毛莨科(Ranunculaceae)乌头属(Aconitum) 6个种的染色体的数目和形态进行了研究,并进行了核型分析。其染色体基数为X=8,核型公式为:两色乌头:2n=2x=2m+10sm+4st;蛇岛乌头为:2n=4x=10m+20sm(SAT)+2st+2B;黄花乌头为:2n=4x=4m+12sm(SAT)+8st+1B;北乌头三倍体为:2n=3x=2M+4m+18sm;北乌头4倍体为2n=4x=4m+28sm。同时,对乌头属下某些种的分类学问题进行了探讨。     

四川当归属八种植物的核型及地理分布研究

本文首次报道四川八种当归属植物的染色体数目和核型。染色体基数x=11,除青海当归为四倍 体植物外,其余种类均为二倍体植物。金山当归 2n=22=20m+2sm;城口当归 2n=22=18m+2sm^sat+2sm;疏叶当归在不同地区有2种核型：2n=22=18m+4sm和 2n=22=16m+6sm;四川当归2n=22=16m+2sm^sat+4sm;茂汶当归2n=22=16m+6sm;青海当归 2n=4x=44=36m+8sm;当归2n= 22=14m+8sm;峨眉当归2n=22=10m+2sm+10st。除金山当归和 疏叶当归的部分居群核型为1A型外,其余种类均为2A型。根据核型的不对称性程度和外部形态分析 了各种类的演化水平,结合四川当归属植物的种类及地理分布,提出四川可能是当归属植物的原始中心和演化中心之一。     

香水月季(Rosa odorata Sweet)不同变种的染色体及核型分析

采用常规压片法对采自11个地点的4个变种进行了以染色体形态和倍性为主的核型分析。结果表明:(1)香水月季原变种是2倍体,核型公式为:2n=2x=14=12m+2sm,核型为1A。(2)大花香水月季4个居群的染色体形态很相似,都是2倍体,核型全为1A,核型公式均是2n=2x=14=12m+2sm,居群间差异主要表现在染色体组的相对长度构成上。(3)桔黄香水月季是2倍体,核型公式为2n=2x=14=10m+4sm,核型为1A。(4)来自不同地方的粉红香水月季在染色体数量和形态上有较大的差异。木家桥和永春的是3倍体,核型公式分别为2n=3x=21=18m+3sm和2n=3x=21=21m;红桥、富民和小河的是2倍体,核型公式分别为2n=2x=14=12m+2sm、2n=2x=14=10m+4sm和2n=2x=14=12m+2sm;除富民的核型为1B外,其他地方的核型均是1A。基于研究结果,讨论了香水月季的核型特征、细胞遗传分化模式、丰富的变异及其在育种中的应用。     

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.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.