大鳞副泥鳅ZZ/ZW型性别决定的细胞遗传学证据

大鳞副泥鳅是鲤形目、鳅科的鱼类。其2n数为48,核型组成为12m+4sm+32 t(雄性),11m+5sm+32t(雌性)。根据银染带和C带特征分析,证实大鳞副泥鳅为ZZ/ZW型性别决定。Z染色体为中部着丝粒染色体,在其长臂端部有Ag -NOR存在。 W染色体为亚中部着丝粒染色体,在其长臂末端也有Ag-NOR存在,同时还有一深染的居间C带,这是W染色体独有的带纹特征。 Abstract:Paramisgurnus dabryanus belongs to Cypriniformes,Cobitidae.Its 2n is 48.The karyotype formula is 12m+4sm+32t(in male),11m+5sm+32t(in female).According to the Ag-NORs band and C-band patterns,we consider that its sex determination is of ZZ/ZW type.The Z chromosome is a metacentric one with Ag-NORs located on its arm end.The W chromosome is a submetacentric with Ag-NORs located on the terminal of its long arm.There is a darkly stained C-band on the long arm of W chromosome.This band is a characteric of the W chromosome.     

阴道毛滴虫染色体组型观察

采用火焰干燥法制备阴道毛滴虫染色体标本,按 Levan等方法,进行核型分析。阴道毛滴虫的染色体数目为n＝10,2n ＝20,染色体的组型为3m、3sm、1st和3T。 Abstract：　The chromosomes ofTrichomonas vaginaliswere prepared by flame-drying method. Data of chromosome were measured and calculated. According to Levan's method, analysis of karyotype was described. The results showed that the chromosome number ofT. vaginalisconsisted of twenty pairs(2n=20) and chromosome type was 3m, 3sm, 1st and 3T.     

阴道毛滴虫染色体组型观察

采用火焰干燥法制备阴道毛滴虫染色体标本,按 Levan等方法,进行核型分析。阴道毛滴虫的染色体数目为n＝10,2n ＝20,染色体的组型为3m、3sm、1st和3T。 Abstract：　The chromosomes ofTrichomonas vaginaliswere prepared by flame-drying method. Data of chromosome were measured and calculated. According to Levan's method, analysis of karyotype was described. The results showed that the chromosome number ofT. vaginalisconsisted of twenty pairs(2n=20) and chromosome type was 3m, 3sm, 1st and 3T.     

家燕与金腰燕染色体的比较研究

本文对家燕和金腰燕的核型、C带和Ag-NORs带进行了比较研究。结果表明,两者的核型基本一致。核型公式:2n=80=2M+4ST+zMwSM+2M+2ST+2SM+8 T+2M+56mT/D。但两者在染色体的相对长度、W染色体大小、G带带型、A g-NORs的数目和分布均存在着差异。文中在家燕No.1、7、W染色体和金腰燕No.1、 6、7染色体的形态划分,金腰燕W染色体的确定及其染色体数目等方面,均与卞小庄、李庆伟的结果不同。 Abstract:A comparative study on karyotype and C-band and Ag-NORs of house swallow and red-rumped swallow has been made.The result shows that the karyotype of them are similar,and their karyotypical formulae is 2n=80=2M+4ST+zMwSM+2M+2ST+8T+2M+56mT/D.But they are different in the relative length of chromosomes,the size of W chromosome,C-band patterns and the number and distribution of Ag-NORs.The chromosomes,the size of W chromosome,C-band patterns and the number and distribution of Ag-NORs.THE result in this paper is different from that of Mr.Bian and Mr.Li in the types of No.1,7,W chromosomes of house swallow and No.1,6,7 chromosomes of red-rumped swallow and the determination of W chromosome and diploid number of red-rumped swallow.     

三个家猪品种和rob易位群染色体分带多态性的比较

对家猪不同品种及家系间的染色体组型、C－带、Ag－NORs多态性进行的研究表明：杜洛克猪、约克夏猪、长白猪体细胞染色体数2n＝38,核型2n＝10sm＋12m＋4st＋12t,而13／17易位纳合子猪（36,rob．13／17）的体细胞染色体数2n＝36,核型2n＝10sm＋12m＋6st＋8t;13／17易位杂合子猪（37,rob．13／17）的体细胞染色体数目为2n＝37,核型为2n＝10sm＋12m＋5st＋10t。5种家猪的C－带在13～18号染色体上存在大、中、小三种类型,且呈多态性分布。杜洛克猪、约克夏猪、长白猪、13／17易位纳合子猪、13／17易位杂合子猪的Ag－NORs均数分别为2．05、2．062．00、1．99、1．98,说明Ag－NORs在品种、个体及细胞间具有多态性.     

泰和乌骨鸡的核型与带型研究

采用外周血淋巴细胞培养--空气干燥法,对泰和乌骨鸡染色体核型和带型进行了研究。结果表明：泰和乌骨鸡体细胞染色体数目2n=78,染色体基本臂数AF=90,1、9号染色体及Z、W性染色体为中央着丝粒（m）染色体,2、4、7号染色体为亚中央着丝粒（sm）染色体,3、6、8、10号染色体为端着丝粒（t）染色体。G带研究表明：前10对大型染色体可分为29个区,190条带。C带处理发现,所有母鸡分裂相中W性染色体都出现C带并整条深染。Ag-NORs研究发现：Ag-NORs常定位于1、2号常染色体短臂和Z性染色体短臂端部;Ag-NORs数目分布范围为1～6;平均每个细胞的Ag-NORs数在雌、雄鸡中分别为2.94和2.96。 Abstract:This study made the chromosome slides of Taihe Silkies by the peripheral blood lymphocyte culture-drying method,and analyzed Taihe Silkies karyotype and band pattern.The results are as follow:The diploid chromosome number of Taihe Silkies was 2n=78,the basic number of chromosome arms was AF=90 and the sex chromosome type was ZZ(♂)/ZW(♀).According to the measured relative length,arm ratio and centromeric index,the first 10 pairs of macro-chromosomes are described as follows:No.1 ,9 and Z,W chromosomes were metacentrics,No.2,4,7 were submetacentrics,and No.3,6,8,10 were telocentrics.Studies on Taihe Silkies′ G-band showed that the first 10 pairs of macro-chromosomes can be divided into 29 zones and 190 bands.Being treated by C-banding technique,a totally dark-stained and easily indentified W-chromosome always showed up in the female metaphase configurations.Ag-NORs were located in the short arms′ telomere of No.1,2 euchromosomes and Z sexchromosome,the Ag-NORs number varied from 1-6. -NORs     

Karyomorphology of three species in Dipentodon （Dipentodontaceae）, Perrottetia （Celastraceae）, and Tapiscia （Tapisciaceae） of the order Huerteales and their phylogenetic implications

Abstract The karyomorphology of three species in Dipentodon （Dipentodontaceae）, Perrottetia （Celastraceae）, and Tapiscia （Tapisciaceae）, namely Dipentodon sinicus, Perrottetia racemosa, and Tapiscia sinensis, was investigated in the present study. Recent molecular research has discovered close relationships among these three genera, which has led to the establishment of the order Huerteales with Perrottetia being placed in Dipentodontaceae. Herein we report the chromosome numbers of D. sinicus and P. racemosa for the first time, and present their karyotype formulas as 2n = 34 = 22 sm ＋ 12 st （D. sinicus）, 2n = 20 = 11 m ＋ 9 sm （P. racemosa）, and 2n = 30 = 22 m（2SAT） ＋ 8sm （T. sinensis）. Asymmetry of their karyotypes is categorized to be Type 3B in D. sinicus, Type 2A in P. racemosa, and Type 2A in T. sinensis. Each of the species shows special cytological features. Compared with Perrottetia, Dipentodon has a different basic chromosome number, a higher karyotype asymmetry, and different karyomorphology of its interphase nuclei, mitotic prophase, and metaphase. Thus, on the basis of these results, we have reservations regarding the suggestion of placing Dipentodon and Perrottetia together in the family Dipentodontaceae.     

陆地棉的核型模式

陆地棉的核型公式为2n=4x=52=30m+20sm(4SAT)+2st(2SAT); 染色体绝对长度平均3.40μm; 臂比值最大与最小的分别是4.02和1.14,平均1.77;随体3对,分别位于第12、19和26对同源染色体的短臂上;最长与最短染色体的比值为2.36;其核型属于Stebbin的2B类型。 Abstract:Karyotype formula of Gossypium hirsutum L.was 2n=4s=52=30m+20m (4SAT)+2st (2SAT); and its absolute lengths of chromosomes averaged 3.40μm; arm ratio differed from 1.24 to 4.02,with the mean value of 1.77; three pairs of satellite chromosomes; the ratio of the longest to the shortest chromosomes was 2.36; and the karyotype belonged to 2B in Stebbin’s classification.     

施氏鲟的核型及DNA含量研究

采用体内注射小牛血清、肾组织细胞短期培养、常见空气干燥法制备了施氏鲟(Acipenser schrencki Brandt)的染色体,并进行了核型分析。施氏鲟二倍体的染色体为238±8条,其核型为78m+12sm+28st,t+120±mc,NF :328±。以外周血红细胞为样本,鸡的红细胞为对照,用美国产的FACStar Plus流式细胞仪测定了施氏鲟二倍体细胞核的DNA含量, 其DNA含量为鸡的5.06倍,绝对含量为11.73±0.68pg/N。 Abstract:Metaphase chromosome specimens of Amur Sturgeon,injected with fetalcalf serum,were prepared from short-term culture of kidney cells with air-drying technique.Its diploid chromosome number is 2n=238±8.Karyotype consists of 78m+12sm+28st,t+120±mc,NF:328±.Diploid nucleus DNA content was measured from the peripheral erythrocytes,using flow cytometer(FACStar Pus,made in USA)and erythrocytes of chick(Gallus sp)as internal standard.DNA content of the fish is 11.73±0.68pg/N and the ratio to that of chickens is 5.06.     

棕黑锦蛇赤峰亚种染色体组型、C带和Ag-NORs研究

以骨髓细胞为材料研究了棕黑锦蛇赤峰亚种的染色体, 结果表明,该物种的2n=36,由8对大型的和10对微小的染色体组成,AF=50。No.4为性染色体(ZW型);所有大型染色体均显示端粒深染C带,但仅NO.2、3、5和Z染色体显示着丝粒浅染C带。W染色体为整条C带阳性;该物种一对NOR分布于微小染色体。锦蛇属核型可能经历过染色体间的着丝粒融合的罗伯逊易位。 Abstract:This paper reports the karyotype,C-bands and Ag-NORs of Elaphe schrenckii anomala(Boulenger).The diploid number,2n=36,comprising 8 pairs of macro- and 10 pairs of microchromosomes in the E.s.anomala.AF=50.The No.4 is sex chromosome,which belong to ZW type.The C-banding technique revealed telomeric constitutive heterochromatin in the whole macrochromosome.But the centromeric C band was only observed in No.2,3,5 and Z chromosome,while a whole W chromosome is constitutive heterochromatinization.Two NORs was observed in group of microchromosome.     

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.