恒山种子植物区系地理成分分析

恒山位于山西北部,有种子植物834种,隶属于342属、84科。种子植物属、种区系成分复杂,比较分析属、种的区系成分,得出恒山以温带成分占优势,在诸多温带成分中北温带分布型、旧世界分布型的属数和温带亚洲分布型、东亚分布型的种数占较高百分比。中国特有种的分布亚型以华北分布亚型种数最多,其次是西北－华北－东北分布亚型和西南－西北－华北分布亚型。     

山西历山种子植物区系研究

历山位于中条山山脉的东段,有种子植物966种,隶属于490属123科。种子植物属种区系成分复杂多样,以温带成分占优势(温带属290属,占总属数的66.36%;温带种504种,占总种数的53.22%)。对科属种区系成分和植被建群种和优势种组成的分析表明,历山具有典型的暖温带落叶阔叶林的特征。应用PCA排序和多样性指数对历山及部分山地植物属的区系地理成分进行了比较研究,结果表明,历山的植物区系成份与太白山、太岳山和泰山较为相似,而与关帝山、芦芽山和长白山有明显差异。     

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。     

赣西北种子植物区系成分分析

赣西北约有种子植物１６９３种,归１５７科,７４０属,比较分析其属,种的区系成分,得出赣西北以温带区系成分占优势,同时受到热带区系成分的影响。在诸多温带区系成分中,东亚分布型属数和东亚分布型种数均占较高百分率,与该地区地处东亚核心地带是一致的。     

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点优势,其中北温带分布型占百分数最高,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     

黄河中游(禹门口—桃花峪)河漫滩种子植物区系地理研究

黄河中游河漫滩共有种子植物818种,隶属于84科358属。区系组成中含20种以上的科有11科,属、种数分别为205属、513种,占整个区系种子植物总属数的57．26％和总种数的62．71％,它们构成了黄河中游河漫滩植物区系的基本成分。对属、种的地理成分分析表明,在种、属水平上均以温带成分占优势。但是,各温带成分的优势度在属、种水平上表现出差异性。相对整个华北区系而言,区系内热带性质的属较为丰富,但不是典型的热带分布属．另外存种的水平上,区系特有现象比在属水平上明显．     

浙江北雁荡山蕨类植物区系特征分析

通过标本和文献查阅以及野外调查,对浙江北雁荡山蕨类植物的区系组成和分布区类型进行了分析.结果显示:北雁荡山共有蕨类植物37科71属156种(含种下分类群);以单种和寡种分布的科和属所占比例最大,分别占总科数和总属数的75.7％和91.5％.该区域蕨类植物科的分布区类型以世界分布型和泛热带分布型为主,分别有14和20科,占总科数的37.8％和54.1％;热带成分总计22科,占总科数的59.5％,而温带成分仅1科.属的分布区类型可划分为9类型2亚型,包含世界分布型17属、热带分布型47属、温带分布型7属;其中,泛热带分布型属数量最多区28属),占总属数的39.4％.种的分布区类型以东亚分布型最多(93种),其中,中国-日本分布亚型有65种,占总种数的41.7％.中国特有种有21种(占总种数的13.5％),其中2种为仅分布于本区域的特有种,分布类型以华东-华南分布最多.由分析结果可见:北雁荡山蕨类植物具有组成丰富、区系起源古老、地理成分多样、热带区系特征明显及特有种数量匮乏等特点,但与周边区域蕨类植物分布有紧密联系.     

南岳衡山蕨类植物区系研究

南岳衡山蕨类植物共计235种(含种下等级),隶属于36科75属。区系分析表明:该地蕨类植物具有较强的热带性质,同时也显示出该区蕨类植物区系向温带渗透和过渡的性质,科、属的分布区类型均以热带、亚热带分布型为主,而种以温带分布型为主。热带、亚热带分布型在该区有18科38属69种,分别占科、属、种数的50.00%、50.67%和29.36%;其中泛热带分布型有14科21属5种,分别占科、属、种数的38.89%、28.00%和2.13%;温带性分布型有3科18属158种,分别占科、属、种数的8.33%、24.00%和67.23%。表明泛热带分布型是该区科、属最重要的分布类型;在种的区系上,温带性成分占明显优势,反映了该区热带成分与温带成分的交汇与兼容。该区虽没有自己的特有属,但具1种特有种,而且中国特有种丰富,共计46种,占总种数的19.57%。该区系与周邻联系广泛,地理成分以华东成分为主。在区系关系上,该区与武夷山、庐山的关系密切,而与万佛山的关系较为疏远。     

山西云顶山自然保护区野生种子植物区系研究

山西云顶山自然保护区位于吕梁山脉中段,有野生种子植物926种,隶属于391属、85科,其中裸子植物2科、4属、6种,被子植物83科、387属、920种(其中双子叶植物72科、311属、756种;单子叶植物11科、76属、164种).种子植物属的区系成分复杂多样,以温带成分占绝对优势,温带属共275属,占总属数的82.08％.种子植物种的区系成分中,温带分布占绝对优势,达566种,占总种数的62.61％,中国特有分布次之,有306种,它们是构成云顶山自然保护区森林植被和灌丛植被的建群种和优势种的主要成分.经与有关山地植物区系和植被组成比较后得出,云顶山自然保护区与庞泉沟自然保护区具有较高的同质性和密切的联系,与五台山次之,而与中条山具有明显的差异.云顶山自然保护区有国家二级保护植物野大豆,还有山西省重点保护植物山西乌头、红景天和党参3种.     

杭州西湖风景区种子植物区系分析

统计分析了杭州西湖风景区野生种子植物区系,该区共有野生种子植物143科,572属,1111种（含种下分类群）。科的分布区类型以泛热带占优势,达48.9%,热带成分的科远多于温带成分的科（64∶28）;从属的分布区类型看,温带成分的属多于热带成分的属（268∶220）;种的分布区类型中,温带成分的种数远比热带成分的种数多（502∶234）;说明该区亚热带北部区系特征显著。另一方面,本区以单种属和寡种属为主,种的分布区类型中,东亚分布（33.7%）与中国特有分布（32.2%）相当,东亚分布中绝大部分属于中国-日本共有。以中国区系分区标准,将中国特有分布种划分成9个分布亚型,其中以华东-华中-华南分布最多（46.0%）。结果表明该区种子植物丰富、地理成分多样,具有明显的华东东部植物区系特征。     

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).