桓仁林蛙与东北林蛙蝌蚪的形态特征及比较

桓仁林蛙（Rana huanrenensis Liu,Zhang,＆ Liu,1993）为一种与东北林蛙（Rana dybowskii）同域分布的林蛙,但其分布区域较狭窄.通过对其蝌蚪的形态特征描述及测量相关的形态学量度并和东北林蛙比较,发现在体色、体型、尾部形态以及身体各部位量度比值等方面存在显著性差异.桓仁林蛙的蝌蚪外形与流水型的蝌蚪相类似,而东北林蛙的蝌蚪则属于典型的静水型蝌蚪.     

辽宁产粗皮蛙的染色体组型研究(图版Ⅳ,下)

用骨髓细胞制片法分析了粗皮蛙的染色体组型 ,结果表明其二倍体染色体数为 2 6 ,可配成 13对 ,有5对大型染色体 (相对长度 >9)和 8对小型染色体 (相对长度 <6 5 ) ,其中 ,第 1、 5、 6、 7、 8对为中部着丝点染色体 ,第 12对为端部着丝点染色体 ,第 2、 3、 4、 9、 10、 11、 13对为亚中部着丝点染色体 ,第 4对为性染色体 ,属XY型 ,X染色体为亚中部着丝点 (相对长度为 10 70 ,臂比指数为 1 72 ) ,Y染色体为亚中部着丝点(相对长度为 12 83,臂比指数为 2 0 2 )。     

吉林省两栖动物一种新纪录--桓仁林蛙

2005年5月,在吉林省东部敬宇县和扶松县进行标本采集中,所采一只林蛙标本经鉴定为桓仁林蛙（Rana huanrenensis Liu,Zhang and Liu）。桓仁林蛙已知分布于辽宁省桓仁县和朝鲜半岛（费梁等,2005）,因此在抚松采集到的桓仁林蛙为吉林省新纪录。现报道如下：雌蛙,体形较窄短,头宽大于头长,鼻间距大于眼间距。鼓膜较小,不足眼径之半。皮肤较光滑,体背和体侧疣少而且小。胫跗关节前达鼻孔,胫长超过体长之半。4、5趾间蹼全蹼。体背为棕褐色,颞部黑色三角斑明显,腹面咽胸部为灰色,腹部白色。     

北京产中国林蛙的染色体组型

通过外周血淋巴细胞短期离体培养方法,对北京产中国林蛙(Rana chensinensis)的染色体组型分析表明,北京产中国林蛙的二倍体染色体数目为2n=24,可分为三组,包括12个大型染色体和12个小型染色体。雌雄个体间未发现与性别决定有关的染色体存在。染色体组型的测量统计分析表明,全部染色体可配成12对,其着丝点位置分别为中部(1,4,5,8和10号)、亚中部(2,3,7,11和12号)及亚端部(6和9号)。除在第7染色体的长臂上具有明显的次缢痕外,在第1—5染色体的短臂上靠近着丝点的部位,以及第6和第9染色体的长臂上靠近着丝点的部位具有微小的次缢痕。根据其染色体的特征,北京产中国林蛙的细胞是研究细胞工程学的良好实验材料。作者还通过北京产中国林蛙与欧洲Rana temporaria的染色体组型的比较分析,确证前者不是后者的一个亚种,建议将过去Pope和Boring(1940)所使用的中国林蛙的学名Rana temporaria chensinensis更改为Rana chensinensis David。     

东北产三种林蛙血细胞的比较研究

应用Wright染色法对桓仁林蛙、东北林蛙和黑龙江林蛙的血细胞进行比较,将所得数据用SPSS软件统计。结果表明：桓仁林蛙、东北林蛙、黑龙江林蛙的血细胞形态、数量上存在差别,这可能与其生活环境和分类地位密切相关。     

沙田柚染色体组型及Giemsa带型分析

本文以沙田柚为材料,对其染色体组型及带型进行了观察分析。组型分析:染色体数目2n=18,根据染色体的相对长度分成大小染色体两种类型,前者包括1、2、3、4和5对,后者为6、7、8和9对,根据臂比,9对染色体能够被分成中部着丝点和近中着丝点染色体两种类型。即第5、7,9对为亚中部着丝点,其余为中部着丝点,第6对染色体上有随体;Giemsa带型:除第二对染色体只显中间带外,其余都显着丝点带,并在3、4、8对染色体短臂上和2、3、1对染色体长臂上均显端带,第2、3,6对同源染色体之间的C带显示杂合性。     

两种无尾两栖类的核型与C-带型的比较研究

用骨髓细胞直接制片法,制作染色体玻片标本。无指盘臭蛙(Rana grahami Liu)的核型,2n=26,NF=52,是由二大组染色体组成的,大型染色体5对,小型染色体8对,其中除第3、7、9号染色体为亚中部着丝点外,其余均为中部着丝点染色体。同时还将无指盘臭蛙的核型与国内已报道的几种蛙属种类的核型作了比较,有关对应染色体的相对长度呈现显著性差异。推测臂间倒位、相互易位等染色体重组是存在的。另外还对无指盘臭蛙和昭觉林蛙(R.taponica chaochiaocnsis)做了染色体C-带的观察比较。     

从细胞色素b基因序列探讨我国林蛙属动物的系统发生关系

对中国林蛙属动物进行了DNA水平的分子系统发生研究,测定了中国林蛙属7种15个样品,侧褶蛙属2种2个样品Cyt b基因长约360bp片段的序列。对这些序列的系统发生分析表明：（1）中国林蛙甘肃种群与东北种群序列差异较大,但尚难根据序列差异来判断它们是不同的亚种还是不同的物种;（2）7种林蛙中,中国林蛙与黑龙江林蛙的亲缘关系最近,与桓仁林蛙最远;（3）支持将昭觉林蛙,镇海林蛙,峨眉林蛙和长肢林蛙归入日本林蛙种组Rana japonica group。     

黑龙江省产胎生蜥蜴的染色体组型研究

本文采用骨髓细胞制片法对分布在黑龙江省孙吴县的胎生蜥蜴染色体组型进行了研究,结果表明其雄性的二倍体染色体数是36,性染色体为ZZ型,2n=34＋ZZ;雌性的二倍体染色体数是35,性染色体为W型,2n=34＋W;所以胎生蜥蜴的性别决定机制为ZZ/W型.胎生蜥蜴的染色体全部为顶端着丝点染色体（除雌性的第5号染色体为亚端着丝点染色体外）,根据其染色体的形态、大小将其配成18对,按照染色体的相对长度把它们分成3组,第Ⅰ组只有第1对染色体（相对长度＞9.0%）,第Ⅱ组包括第2、3和4对染色体（9.0%＞相对长度＞7.0%）,第Ⅲ组包括第5～18对染色体（相对长度＜7.0%）.     

中亚林蛙的核型,C带和银带研究及田野林蛙起源的探讨

中亚林蛙（Ranaasialica）的核型为2n＝26,NF＝52．第2号染色体短臂有一条近端着丝粒区C带。第10号染色体长臂上有一对标准NORs。本文认为,田野林蛙（Ranaarvalis）起源于欧洲,是欧洲林蛙群与亚洲2n＝24的林蛙群间的过渡种类。     

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