珠穆朗玛峰国家自然保护区蕨类植物区系研究

在野外实地调查和室内标本整理以及查阅文献的基础上,对珠穆朗玛峰自然保护区蕨类植物区系进行研究,为探讨喜马拉雅植物区系的起源以及该区生物多样性的保护提供资料。结果表明:(1)珠穆朗玛峰自然保护区共有蕨类植物193种,隶属于31科59属,其中优势科为鳞毛蕨科(51种)、水龙骨科(41种)、蹄盖蕨科(22种)、铁角蕨科(10种),优势属为耳蕨属(27种)、鳞毛蕨属(20种)、瓦韦属(17种)。(2)科的分布区类型有8种,以泛热带分布型(55.56%)为主;属的分布区类型有14种,以泛热带分布型(23.81%)、中国-喜马拉雅分布型(19.05%)为主;蕨类植物以土生(55.88%)为主,石生(24.35%)和附生(21.76%)也占有一定比例,缺乏水生蕨类。(3)珠穆朗玛峰自然保护区蕨类植物区系成分与南迦巴瓦峰地区联系最为密切,其次为横断山地区和尼泊尔,与九塞沟自然保护区、秦岭地区有一定的联系,与西双版纳地区的关系较为疏远。     

浙江省凤阳山自然保护区蕨类植物区系的研究

经野外调查和资料整理已知凤阳山自然保护区共有蕨类植物37科74属196种和7变种.主要科为鳞毛蕨科、水龙骨科、金星蕨科、蹄盖蕨科、铁角蕨科、卷柏科、膜蕨科,主要属为鳞毛蕨属、铁角蕨属、卷柏属、复叶耳蕨属、瘤足蕨属、凤尾蕨属、瓦苇属.分布区类型以世界分布和泛热带分布科、泛热带分布属、东亚分布种为主,表现出亚热带向暖温带过渡的特点.与邻近6山蕨类植物区系相似性系数的比较表明,与凤阳山蕨类植物区系亲缘关系最近的是浙江九龙山.凤阳山共有57种中国特有蕨类,有较高的保护价值.     

海南尖峰岭自然保护区蕨类植物区系分析

对海南尖峰岭国家级自然保护区的蕨类植物区系进行了分析。结果表明：自然保护区内共有蕨类植物165种,隶属于41科84属,优势科有7科,分别为水龙骨科、铁角蕨科、金星蕨科、蹄盖蕨科、叉蕨科、膜蕨科、鳞毛蕨科,含5种以上的优势属有7属,分别为铁角蕨属Asplenium、卷柏属Selaginella、观音座莲属Angiopteris、鳞始蕨属Lindsaea、凤尾蕨属Pteris、短肠蕨属Allantodia、鳞毛蕨属Dryopteris;根据植物的现代地理分布,本区蕨类植物科、属、种的热带成分分别占非世界分布的96.6%、90.4%、72.2%,表明本区蕨类植物区系具有较强的热带性质;本区蕨类植物的属内种类贫乏,含1种的属占63.1%,含2～3种的属占21.4%;生态类型多样,主要有土生蕨类、石生和附生蕨类;苏铁蕨Brainea insignis、水蕨Certopteris thalictroides、金毛狗Cibotium barometz、桫椤Alsophila spinulosa、黑桫椤Gymnasphaera podophylla、大叶黑桫椤Gymnasphaera gigantea是本区国家重点二级保护珍稀濒危蕨类植物,应采取措施加强保护。     

诸广山地区石松类和蕨类植物资源及区系研究

通过多次野外调查及资料整理,对诸广山地区石松类和蕨类植物的资源组成、地理成分、生态环境等方面进行了分析研究。结果显示:(1)诸广山地区共有石松类和蕨类植物37科、87属、249种,优势科为鳞毛蕨科、水龙骨科、金星蕨科、蹄盖蕨科、凤尾蕨科,优势属为鳞毛蕨属、凤尾蕨属、复叶耳蕨属、卷柏属,单种科有12个,单种属有39个,这些丰富度高的蕨类中既有古老孑遗种又有新生代年轻种,反映了该区蕨类植物的古老性与延续性。(2)从分布区类型来看,该区石松类和蕨类植物区系中以热带性质的科和属占绝对优势,分别占除世界分布类型外总科、属数的89. 3%和77. 6%,以泛热带分布类型为主。但种的地理成分复杂,温带成分略显优势,占50. 6%,以东亚分布类型为主,中国特有分布种占23. 3%;热带成分的种占26. 1%,以热带亚洲分布类型为主。表明该蕨类植物区系具有热带亲缘性,是明显的热带向温带过渡地段。(3)该区以土生蕨类群落类型为主,树生蕨类与石生蕨类随海拔升高而增多,物种丰富度在800-1 500 m处最高。     

深圳梧桐山蕨类植物区系

对深圳梧桐山蕨类区系进行了研究。结果表明,梧桐山蕨类植物区系由33科63属126种和2变种组成,含8种以上的科有水龙骨科、金星蕨科、鳞毛蕨科、卷柏科、蹄盖蕨科和风尾蕨科;依据植物的现代地理分布,梧桐山蕨类植物种的分布可以划归为9个分布区类型和6个亚型,其中热带亚洲分布成分和东亚分布成分构成了该区系的主体。区系分析表明,该植物区系带有较明显的热带性质,约67％的种类属于热带分布。     

粤东蕨类植物区系初步研究

通过对粤东蕨类植物的调查和统计分析得出:粤东地区共记录蕨类植物258种,隶属于45科95属,区系较为丰富;粤东的蕨类区系属于东亚植物区向古热带植物区的过渡地带,以水龙骨科、鳞毛蕨科、蹄盖蕨科、金星蕨科等12个科为优势科,以铁角蕨属、凤尾蕨属、鳞毛蕨属等10个属为优势属。从种的区系成分来看,粤东蕨类植物区系主要是热带成分与东亚成分的综合体,以中国—日本分布、热带亚洲、中国特有种分布为最丰富,反映了东亚与热带亚洲的蕨类植物区系的统一性和紧密联系。特有程度低于当地种子植物区系。与相关的6个地区的比较,说明纬度和海拔高度对区系的影响较大。     

茂兰国家级自然保护区石松类和蕨类植物区系特征

本研究通过野外考查、标本采集和分类鉴定，以及文献资料整理，对贵州茂兰国家级自然保护区石松类和蕨类植物区系组成和分布区类型进行统计分析。结果显示：(1)茂兰国家级自然保护区共有石松类和蕨类植物32科76属237种，优势科为鳞毛蕨科(Dryopteridaceae)、蹄盖蕨科(Athyriaceae)、凤尾蕨科(Pteridaceae)、水龙骨科(Polypodiaceae)；优势属为双盖蕨属(Diplazium)、卷柏属(Selaginella)、凤尾蕨属(Pteris)。(2)分布区类型以东亚广布和热带亚洲分布为主，生态类型以阴生植物和土生植物居多。(3)与其他地区的区系比较显示，茂兰与广西花坪物种相似性系数最高，依次是贵州梵净山、四川峨眉山和云南马关县。     

重庆地区蕨类植物区系的初步研究

对重庆地区蕨类植物从科、属分布区类型进行了统计分析,同时将该区区系特征与其它几个地区进行了对比分析.结果表明:(1)该区共有蕨类植物389种(含变种和变型),隶属于109属,43科.(2)该区蕨类植物中优势科、属十分明显,其中优势科为:鳞毛蕨科、金星蕨科、水龙骨科、蹄盖蕨科、凤尾蕨科;优势属为鳞毛蕨属、耳蕨属、凤尾蕨属、铁角蕨属、卷柏属、凤丫蕨属.(3)从蕨类植物科、属分布区类型的所占比例来看,该地区区系性质以热带成分占优势,其中热带分布科22科,占总科数的75.00%;热带分布属有60属,占总属数的64.52%(剔除世界分布).(4)本区区系成分古老,古老孑遗的科属较为丰富,但特有现象不明显.(5)该区地形、气候条件对于蕨类植物的散布和充分发育比较适宜,为其在该区的充分发育创造了极为有力的条件.(6)经对比分析和聚类分析表明:该区与临近的几个地区属的相似性系数很高,特别是与西南地区的西藏、横断山区的属相似性系数较大,表明区系上与这些地区有着广泛的联系;而与华北的内蒙古,东北的辽宁等相距较远的地区属的相似性系数较低,表明区系上联系较为疏远.     

浙江凤阳山-百山祖自然保护区蕨类植物区系研究

通过对凤阳山——百山祖自然保护区蕨类植物野外资源调查及区系分析,可以认为,凤阳山——百山祖保护区共有蕨类植物39科、79属、249种(含变种),主要科为鳞毛蕨科、水龙骨科、金星蕨科、蹄盖蕨科和膜蕨科;主要属为鳞毛蕨属、复叶耳蕨属、铁角蕨属、蹄盖蕨属和瓦韦属,其中以鳞毛蕨属和复叶耳蕨属分布相对集中。属的分布类型以热带成分为主,种以东亚分布类型和中国特有种为主,并含有72种中国特有和珍稀蕨类植物。     

安徽祁门地区蕨类植物区系研究

安徽祁门地区蕨类植物共有107种(包括变种、变型),隶属于28科56属,其中发现安徽地理分布新记录种1个,即丝带蕨(Drymotaenium miyoshianum).该区的蕨类植物优势科为鳞毛蕨科(Dryopteridaceae)、水龙骨科(Polypodiaceae)和蹄盖蕨科(Athyriaceae);优势属为鳞毛蕨属(Dryopteris)、卷柏属(Selaginella)和复叶耳蕨属(Arachniodes).属的地理成分以泛热带为主,亚热带和温带分布次之;种的地理分布则以中国-日本分布和中国特有分布为主.祁门蕨类植物区系在区系区划上应属于典型的华东地区.该区的蕨类植物生态类型以土生为主.种的相似性分析和属的聚类分析表明:该区系与三清山和天童山的关系密切,而与白石砬子等关系疏远.     

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.