红树科植物的化石记录及植物地理史

红树科植物化石种类有红树属Rhizophora、秋茄属K andelia、角果木属Ceriops和木榄属Bruguiera等4属,主要分布于亚洲、欧洲、非洲、大洋洲和美洲的古新世至全新世地层中。红树科植物化石记录显示:该科植物很可能于古新世至始新世早期起源于环特提斯海沿岸,中始新世开始从这一起源中心迅速向世界其它地方包括亚洲、欧洲、非洲、大洋洲和美洲等地扩散;渐新世在上述地区继续这一扩散历程,但在欧洲的化石记录消失;中新世时在亚洲、非洲、大洋洲和美洲达到了极盛期;上新世开始分布范围有所缩小,更新世则进一步缩小;一直到全新世才又重新繁盛起来。红树科植物的这一分布格局和地史演变是与地质时期大陆漂移、洋底扩张、第四纪冰川活动、古气候和古地理的变迁紧密相连的     

中国高校校园植物的多样性分析

城市生物多样性与人类生活密切相关,而校园植物是其中的重要一环。本研究统计了39个中国高校校园的完整植物名录,并对其进行区域划分,进而研究各区域内校园植物的多样性和区域间植物组成的相似性。此外,我们还选取了两个常见行道树分布的科——樟科(Lauraceae)和杨柳科(Salicaceae),分析它们在不同纬度校园间分布的差异性。结果显示,我国南方地区校园植物的多样性较高,但各区域间较为相似,相似性系数在0.675～0.721;北方地区的校园植物虽然丰富度较低,但各区域间的差异较大,相似性系数在0.417～0.609。与东、西部地区相比,同纬度中部地区的校园植物特异性较低。樟科植物的丰富度从南向北依次递减,杨柳科植物的种丰富度从南向北依次递增。地理环境和气候因素导致了这些差异的形成。这些信息有助于各地校园合理配置植物,并将为各地区城市生态系统的管理提供参考。     

罂粟属花卉

正罂粟属植物是一类以欧洲中南部至亚洲温带地区为分布中心的植物,少量分布于美洲、大洋洲和非洲南部,有100多个物种。我国有4个原产的野生种,主要分布于秦岭以北海拔1000米以上的山区。罂粟属有许多美丽的观赏花卉,如东方罂粟、虞美人、冰岛罂粟、波斯罂粟等,都是近年来常见栽培的地被景观花卉。罂粟属中最著名的     

中国壳斗科植物属的空间多样性及差异

该文采用地理信息系统技术,以县为空间数据的基本单元,以壳斗科植物为研究对象,制作属的空间分布图,计算空间相似性系数,分析壳斗科各属的空间多样性及其差异。结果表明,三棱栎属为连续分布,与其他属的空间分布最不相似,其他属均为间断分布,其中锥属、青冈属、柯属空间分布最相似,这3个属的多样化中心均有云南南部,水青冈的多样化中心比前3个属偏北,栎属多样化中心是四川西南部和云南西北部,西北地区东南部是联系南方与北方栎属植物的重要通道。     

中国东北样带（NECT）东部森林区的植被与表土花粉的定量关系

基于中国北东样带东部森林区８个植被样方和表土花粉资料,定量分析了每种植物与表土花粉类型的关系。结果表明：花粉类型与植物关系密切,在α＝０．０５的显性水平上,相关系数（ｃｏｒｒｅｌａｔｉｏｎ ｃｏｅｆｆｉｃｉｅｎｔ）Ｃ值大都在０．５以上;表土花粉组合与植物群落间有较大的相似性,相似系数（ＣＣ）大于５０％。采用定量描述花粉与植物关系的参数：联合指数（ａｓｓｏｃｉａｔｉｏｎ ｉｎｄｅｘ）Ａ、超代表性指     

世界蓑藓属植物分布式样及其系统演化和生物地理学意义

蓑藓属（Macromitrium）是苔藓植物分类、生态学研究及生物多样性保护的重要类群。以“Index Muscorum”中的14个藓类植物地理分布单位为分析区域,基于标本信息和相关文献,在分类修订的基础上,统计了世界蓑藓属274种植物在14个地理单位的分布数据,基于这些数据,应用聚类分析和除趋势对应分析法,分别得到了14个地理单位的聚类图和三维空间图,直观展示了世界蓑藓属植物的地理分布格局。发现蓑藓属植物区系在东亚（As2）、大洋洲（Oc）、南亚和东南亚（As3,As4）、非洲（Afr2,Afr3,Afr4）、中美洲-南美洲（Am2,Am3,Am4,Am5）、澳洲（Austr1,Austr2）存在区域分化。热带亚洲和热带美洲是世界蓑藓属植物的多样化中心。除长柄蓑藓（M.microstomum（Hook.&Grev.）Schwägr.）在14个地理单位均有分布外,大部分种类分布限于少数或仅一个地理单位。蓑藓属植物在东亚、热带亚洲、热带美洲和澳洲不仅种类存在明显分化,而且形态性状也有区域特点。根据蓑藓属植物的现代分布式样,探讨了其系统演化和生物地理学意义。     

贵州省野生凤仙花属植物物种多样性与地理分布

该研究以贵州省野生凤仙花属植物为研究对象,在建立物种名录和地理分布数据库的基础上,对其物种多样性和地理分布格局进行研究。通过查阅文献资料和实地调查,从物种组成、特有性、水平分布、垂直分布和相似性等方面进行分析,最后采用筛除算法确定贵州凤仙花属植物分布的热点地区,为贵州省凤仙花属植物资源的研究和持续利用提供理论参考。结果表明:(1)贵州省凤仙花属植物共记载60种(含种下等级),分布于69个县级行政区,有55个中国特有种和10个贵州特有种,垂直分布以1 000～1 500 m海拔段最为丰富。(2)通过相似性系数分析,发现贵州与湖南的相似程度最高;并筛选得到9个热点县,共代表了86.67%的凤仙花属植物。(3)贵州省气候温暖湿润,具有典型的高原喀斯特地貌,凤仙花属植物的物种多样性和区域特有性明显。     

龙脑香科植物的地理分布

龙脑香科(Dipterocarpaceae)为一泛热带分布的科。据我们研究统计全世界龙脑香科植物约有3个亚科,16属529种,间断分布于热带亚洲、非洲和美洲(图1)。其中92%的种类分布于热带亚洲,为热带亚洲植物区系中的一个优势种;8%的种类散布于热带非洲和热带美洲。龙脑香科是植物学家和热带林业工作者研究较为深入的类群。自林奈(Carolus Linna-eus)1737年建立瓦特香属(Vateria)到布卢姆(     

假刺苋——中国大陆一新归化种

报道了广东省潮州市韩江沿岸发现的中国大陆一新归化种——假刺苋(Amaranthus dubius Mart.ex Thell.)。该种原产热带美洲及西印度群岛,已经引入并局部归化于欧洲、热带亚洲地区和非洲,在中国台湾已经归化。通过野外调查,获得该种的详细特征与生境等信息,并讨论了与其他苋属植物的区别及其潜在的入侵性。此外,还提供了用于检索中国苋属植物的分类检索表。     

亟待保护的中国红树林

红树林是生长在热带、亚热带沿海潮间带,以红树植物为主体的湿地木本植物群落。红树植物分为两大区系,即东方区系和西方区系。东方区系指分布于印度-西太平洋地区的红树植物,而西方区系是指分布于大西洋-东太平洋地区的红树植物。其中,印度-西太平洋地区东南亚的红树资源最为丰富。     

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.