浙江武义森林植被区系的地理成分研究

提供了浙江武义的森林植被区系。该区系具有丰富的植物种类、古老植物和珍稀濒危植物,温带－温亚热带成分占优势,地理成分与世界各地植物区系有广泛的联系。该区系有１４个类型的成分,东亚成分、泛热带成分及东亚－北美间断成分具有较多的属,而地中海、西亚及中亚成分、温带亚洲成分及世界成分具有较少的属。     

中国阿尔泰山种子植物区系研究

中国阿尔泰山植物区系是西伯利亚森林植物区系的一部分,种子植物共有９４科５２８属１４９１种。属的分布区类型分析表明,该植物区系属于温带性质,具有多域性。生活型、生态型分析表明,本区植物以地面芽植物、中生植物占绝对优势,与其区系的温带性质一致。该植物区系成分主要是北方成分、古地中海成分和本地发生成分。     

新疆种子植物科的区系地理成分分析

对新疆种子植物区系科的组成和地理成分进行了分析。结果表明,新疆种子植物区系地理成分多样,而以温带成分为主,共有55科,包括热带至温带、亚热带至温带、温带、温带至寒带的科,占总科数的47.8%,若除去世界广布科,则所占比例更高,达73.3%,纯粹的热带成分、热带至亚热带成分较少,这反映出新疆种子植物的分布与本地区所处的气候带相适应。该区种子植物的表征科和优势科分属于各类成分,但大部分为世界广布成分。本研究表明,在科级水平上,该区系是安加拉区系的一部分。     

中条山木本植物区系地理成分分析

中条山位于山西省南部,有木本植物478种,隶属于73科164属。其中裸子植物5科10属18种;单子叶植物2科2属6种;双子叶植物66科152属454种。分析结果表明,科、属、种的区系地理成分复杂多样,科的分布区类型以热带-亚热带-温带分布占优势,其次是温带分布;属的分布区类型以温带成分占优势,其中北温带分布型所占百分数最高,反映出该区系的温带性质;种的分布区类型中国特有分布的种数最多,其次是东亚分布、温带亚洲分布。该区系木本植物的起源具有古老性,区系地理成分的渗透性、交汇性和过渡性较明显。中条山是华北木本植物区系中珍稀濒危植物较为集中的地区,有国家级重点保护植物15种。     

安徽珍稀濒危植物区系探讨

在深入调查的基础上,对安徽珍稀濒危植物区系组成和地理成分进行了详细的统计分析,探讨了该区系的组成特点及地理分布特征。结果表明,该区系属温带亚热带性植物区系,具有珍稀濒危物种丰富,古老、孑遗植物众多;地理成分复杂,区系联系广泛;过渡性质明显,温带亚热带成分占优;特有现象显著,华东区系特征典型等基本特征。在植物区系亲缘上,该区系隶属东亚植物区、中国-日本森林植物亚区、华东地区,与华中植物区系关系密切,受西南植物区系影响深刻。     

中国南部高等真菌的热带亲缘

中国南部,特别是北回归线以南的地区,高等真菌区系与世界热带真菌区系有着广泛的联系。该地区高等真菌具有明显的热带性质,主要有泛热带成分、热带亚洲—热带非洲和热带亚洲的成分,尽管在该区高等真菌区系中也有相当比重的温带成分。该区系中某些属种可能有古南大陆起源的背景,另一些区系成分与热带亚洲的有密切的亲缘关系。     

甘肃省马衔山地区种子植物区系的研究

分析了甘肃省马衔山地区种子植物区系,用主成分分析（Ｐ．Ｃ．Ａ）和信息聚类（Ｉ．Ｃ．Ａ）方法对该区系与国内其它１０个有代表性地区的种子植物区系进行了对比分析。其结果为：１．该区系温带性质十分明显,是一个汇集四大区系成分的过渡带;２．该区系起源于第三纪亚热带亚高山森林植物区系,随青藏高原的隆起和中亚干旱区的形成而分化形成;３．该区系与六盘山植物区的关系最近。该区系隶属于泛北极植物区,中国－日本森林植物     

湘西北壶瓶山自然保护区植物区系

壶瓶山自然保护区具有丰富的植物区系成分,现知维管束植物有205科(蕨类和拟蕨类 植物40科,裸子植物7科,被子植物158科),839属,约1961种(包括154变种)。其中,古 和原始的科、属不乏其代表。从种子植物属的分布区类型的比较分析,该区具有我国15个种子植物属的分布区类型中的14个,表明了与世界各地区植物区系的联系程度。另一方面,该 地区的植物区系虽含有丰富的热带成分,但根据各类温带属占该区总属数的百分比以及分布于该地区的中国特有属中的木本属几乎所有都是落叶的乔木或灌木,该区的植物区系性质明显偏重于温带性质。而且,这种温带性质可能与该区的山体海拔高度有着重要的联系。     

浑善达克沙地种子植物区系分析

对地处内蒙古中部农牧交错地带的浑善达克沙地种子植物科的组成特征和区系地理成分进行了分析,并与内蒙古植物区系进行比较.结果表明,浑善达克沙地种子植物种类相对丰富,共有种子植物1191种,隶属于402属84科.植物区系地理成分多样,而且以温带成分为主,在诸多温带成分中北温带分布型的种数占有较高的百分比,菊科和禾本科在本区系中所占的比例最大,该区系植物属种趋向于分布大科的特点,这反映出浑善达克沙地植物的分布与本地区的气候带相适应,地带性植被具有温带草原与荒漠的特征;该区种子植物的优势科也分属于各类成分,具有集中分布于大科的特点,大部分为世界广布成分;植物区系成分起源古老,区系地理成分复杂且具有过渡性;同时该植物区系具有明显的脆弱性.     

安徽珍稀濒危植物区系探讨

在深入调查的基础上,对安徽珍稀濒危植物区系组成和地理成分进行了详细的统计分析,探讨了该区系的组成特点及地理分布特征。结果表明,该区系属温带亚热带性植物区系,具有珍稀濒危物种丰富,古老、孑遗植物众多;地民分复杂,区系联系广泛;过渡性质明显,温带亚热带万分占优;特有现象显,华东区系特征典型等基本特征。在植物区系亲缘上,该区系隶属东亚植物区、中国－日本森林植物亚区、华东地区,与华中植物区系密切,受西南     

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.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

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.     

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).