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。     

山西五台山种子植物区系分析

五台山有种子植物865种,隶属于392属92科,其中裸子植物3科, 6属, 7种,被子植物89科, 386属, 858种(双子叶植物76科, 294属, 699种,单子叶植物13科, 92属, 159种)。五台山种子植物属的区系成分类型多样,具有明显的温带色彩。突出特征是温带成分占绝对优势,达255属,占总属数的73.48%(其中北温带成分156属,占总属数的为44.96%),在植物区系的组成中具有重要作用。在五台山种子植物种的区系成分中,中国特有种占绝对优势,达286种,占总种数的33.41%,它们是构成五台山优势植被类型的建群种和优势种的主要成分,如华北落叶松、油松、青木千、黄刺玫、虎榛子、蚂蚱腿子等。类平均聚类结果表明,五台山种子植物区系成分与北京东灵山、百花山关系最为密切,与长白山关系次之,与关帝山、大青山有一定差异,与太岳山、太行山和中条山差异较大,与太白山差异最明显,这主要由它们的生态地理条件、区系成分的组成及植被建群种和优势种等差异所决定。     

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.     

小五台山种子植物区系研究

小五台山位于河北省西北部, 共有种子植物97 科, 467 属, 1 148 种。种子植物属的区系成分复杂:温带成分占优势, 温带属280 属, 占总属数的69.31%。通过对小五台山和部分山地植物区系的属相似性比较, 结果显示:小五台山与东灵山、雾灵山十分相似, 与关帝山、太岳山有一定的相似性, 而与长白山、泰山、伏牛山、神农架相似性偏低。     

峨眉山槭属植物的地理分布和区系特点

本文报道了分布于四川峨眉山槭属植物,计26种1变种。讨论了槭属植物在峨眉山的垂直分布与水平分布规律。峨眉山槭属植物的区系组成是亚热带和温带东亚区系成分。     

峨眉山槭属植物的地理分布和区系特点

本文报道了分布于四川峨眉山槭属植物,计26种1变种。讨论了槭属植物在峨眉山的垂直分布与水平分布规律。峨眉山槭属植物的区系组成是亚热带和温带东亚区系成分。     

广西元宝山植被种子植物区系初步研究

组成元宝山植被的种子植物共有118科337属732种,区系统计分析表明:(1)科级和属级的区系成分都表现为热带性质稍强于温带性质,亚热带区系性质明显。在元宝山植被区系中,热带亚热带成分与温带成分相互交融,这正是亚热带山地植物区系的一个基本特征。(2)泛热带分布、热带亚洲分布、北温带分布、东亚和北美洲间断分布和东亚分布的属为该植被区系主要构成成分。(3)元宝山植被中存在许多区系上孑遗、古老、孤立的植物类群,并且特有成分丰富,具有重要的保护价值。(4)裸子植物丰富,针叶林群落类型多样,是元宝山植被组成的突出特点。     

辽宁棋盘山森林公园种子植物区系研究

在实地考察和标本采集鉴定的基础上,对辽宁棋盘山森林公园种子植物的组成、分布类型和区系特征进行了分析研究.结果表明,棋盘山森林公园共有种子植物69科187属264种,其中裸子植物4科9属23种,被子植物65科178属241种;植被类型多样,区系地理成分复杂,具有强烈的温带性质;区内具有一定数量的重点保护植物,但特有现象不...     

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.     

珍稀濒危植物长苞铁杉群落植物区系分析

对天宝岩国家级自然保护区3600m^2的长苞铁杉群落植被进行调查。结果表明,该群落有维管束植物49科86属140种,其中蕨类植物7科7属9种,裸子植物2科4属4种,被子植物40科75属127种。植物区系地理成分中,科属组成以泛热带分布为主,温带成分占有一定比例;种组成以中国特有分布和东亚分布为主,而温带成分占较大比例,并伴有一定的热带成分;区系起源古老,保留有大量原始植物,且群落具有濒危性。     

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.