北京东灵山地区植物群落多样性的研究

利用盖度和重要值两个多度指标对北京东灵山地区小龙门林场的５个植物群落进行了研究,以考察样本大小对多样性测度的影响,并设计了３处方法来确定临界样方数量（即多样必否则测度趋于稳定时的样方数量）。结果表明,用盖度和重要值作为多度指标进行植物群落多样性的研究是合适的,并且得出的结果也是一致的;当取比例因子ｋ１＝０．２时,计算临界样方数量的第二种方法与直观判断比较吻合;丰富度指数不太稳定,临界样方数量在２０     

鼎湖山森林群落β多样性

β多样性反映了环境被物种分割的程度或生境多样性,具有重要的意义。鼎湖山自然保护区地处南亚热带,植被保存完好,具有较高的生物多样性,而当前对其β多样性的研究则相对缺乏。以鼎湖山一条10m×1160m植被样带数据为基础,从不同尺度单元研究了鼎湖山森林群落β多样性。发现:(1)β多样性依赖于尺度,对于南亚热带森林群落要得到比较稳定可靠的β多样性测度数据,乔木层取样尺度应该在10m×20m附近,而灌草层应该在2m×20m或相应面积以上。(2)数量数据β多样性测度总体上优于二元属性数据测度,对于数量属性数据测度应给予更多的关注,而Cody指数则能指示群落交错区。(3)鼎湖山样带β多样性随海拔呈现不规律变化的格局,而沿纬度梯度,鼎湖山森林群落βc大于东灵山森林群落,与Rapoport法则预测结果一致。     

基于系统保护规划方法东北生物多样性热点地区和保护空缺分析

根据东北地区生物多样性特征,利用系统保护规划方法和国际上常用的保护规划软件C- plan,计算了规划单元的不可替代性值,确定了区域生物多样性热点地区,并根据保护区分布现状进行了生物多样性保护空缺分析.结果显示,东北地区不可替代性较高的热点地区有4个,分别是:(1)长白山西北部林区,(2)大兴安岭北段山地区,(3)大兴安岭南部森林与草原过渡区,(4)松嫩平原中部湿地区. 在优先、一般、非优先3个等级中,需要优先保护地区的总面积是19.49×104km2,约占区域总面积的20.91%.同时,根据已建保护区分布情况研究发现,区域内存在3个明显的保护空缺,即长白山西北部林区、大兴安岭北段山地区和大兴安岭南段森林草原过渡区.建议新建和扩建保护区,同时建立生态廊道把相应的保护区关联起来,以实现区域内生物多样性保护目标.     

特有植物多样性分布格局测度方法的新进展

特有植物是生物多样性保护的重要对象,对其分布格局的研究可以为生物多样性优先保护区的确定提供重要参考.研究人员利用多种测度和分析方法,在不同地理区域对特有现象的分布格局开展了大量研究.随着分子系统学方法的不断完善及一些空间统计分析方法的引入,新的生物多样性测度方法应运而生.本文介绍了生物多样性测度方法的类型及其特点、应用现状与前景.这些测度方法的发展经历了从单一的时间或空间格局到时空格局统一的过程,具体涉及物种丰富度、谱系多样性、进化特异性以及这3种测度方法整合空间分布加权的算法.其中,谱系多样性指数(phylogenetic diversity)、谱系特有性指数(phylogenetic endemism)以及空间加权的进化特异性指数(biogeographically weighted evolutionary distinctiveness)尤其值得关注.中国特有植物分布格局的研究需要在以下4个方面进一步开展工作:(1)完善特有物种的分布格局研究;(2)加强物种的测序工作,完善谱系多样性格局的分析;(3)结合系统发育信息,揭示谱系多样性及进化历史的分布格局,进而深入开展物种p多样性和谱系p多样性的研究;(4)加强物种分布区变化的模拟,在时间维度上探讨特有现象的变化格局,为生物多样性保护提供更完善的理论支持.     

泛函连接网络计算软件及其在生物多样性研究中的应用

针对农田生物多样性分析的需要,研制出泛函连接网络（FLANN）计算软件。该软件由7个Java类和1个HTML文件组成,是一种Internet在线计算工具,可运行于多种操作系统和Web浏览器上,并在各种类型的PC及工作站上使用,可读取多种类型的数据库文件。对水稻田昆虫生物多样性的两组取样调查数据Zmar18和Zapr15,用生物多样性工具软件LUMP和非监督分类－离差平方和聚类法进行统计归纳及分类,分别划分为21个和20个功能群,各包含60个样本。以FLANN计算软件对昆虫生物多样性进行了模式分类分析。结果表明,泛函连接网络的模式分类及预测与实际测查结果吻合良好。泛函连接网络Internet在线计算软件的应用可促进生物多样性数据采集和分析的规范化,有利于数据和信息共享,也为形成高度的生物多样性智能分析系统提供了一种工具。     

中国自然保护区分布现状及合理布局的探讨

为了保护中国丰富的生物多样性, 我国已经建立了大量的自然保护区。评价这些保护区的布局对于生物多样性的有效保护无疑是十分重要的。本文收集了截至2007年底我国建立的2,047个保护区的有关资料, 利用地理信息系统技术, 分析了这些保护区的分布现状和生物多样性的保护状况, 包括保护的植被类型、野生保护物种以及热点地区。结果表明: 我国自然保护区的覆盖面积达到145.7万km2, 占中国陆地面积的15.2%, 超过世界平均水平(13.4%); 在我国47种自然植被类型中, 有21种植被类型的被保护面积比例低于10%, 说明这些类型可能没有得到充分的保护。应用Dobson筛除算法对216个保护区中的保护物种进行筛除分析, 发现仅西双版纳、武夷山、长白山、高黎贡山、祁连山5个保护区即包含了381个保护物种(约占总数783种的50%); 前21个保护区可包含占总数75%的保护物种(590种)。根据不同方案划分的生物多样性热点保护地区仍存在一些保护空缺地, 如新疆北部、四川与长江以南地区, 因此, 我国的保护区布局有待进一步改进。     

地带性森林群落物种多样性的比较研究

在群落调查以及文献收集的基础上,对暖温带地区、暖温带和亚热带过渡地区、亚热带地区以及热带地区的典型地带笥植被不同群落类型群落多样性进行了分析和研究。结果发现这４类地区物种多样性的变化具有一定的规律性,具体表现在热带地区群落乔木层的物种丰富度和多样性为最高,然后依次是亚热带地区、秦蛉地区和东灵山地区;灌木层的物种丰富度和多样性则以亚热带地区为最高,其次是秦岭地区,热带地区的则仍高于东灵山地区;灌木层     

北京东灵山地区不同海拔柴胡居群的遗传多样性

利用ISSR技术对北京东灵山地区不同海拔的6个柴胡居群进行分析,观察不同海拔柴胡居群的遗传多样性。结果表明,东灵山地区不同海拔柴胡居群的遗传多样性差异较大,海拔1135m居群表现出较高的遗传变异水平,高海拔居群遗传多样性较低;遗传距离与海拔差距有一定的相关性,相邻海拔的不同柴胡居群间具有相对较低的遗传距离;柴胡具有较强的遗传分化趋势,且大部分变异存在于居群内。不同海拔导致的异质生境及基因流是影响柴胡居群遗传多样性的主要原因。     

多样性排序:方法与实例

多样性已经成为生态学理论与实践中的一个很重要的概念 ,很多多样性指数被引进或设计出来 ,并被广泛地应用于生态系统管理以及环境监测与评价之中。然而 ,很多学者对其也提出了疑议 ,因为当用不同的多样性指数对一组群落进行比较时会得出不同的顺序。Patil和Taillie等人提出用含有一个参数的多样性指数族可以潜在地解决这个问题。本文对这个类型的 1 4种方法做了评述 ,并将其分为 4组。证明了组内各方法间是等价的 ,而不同组的各方法间是不等价的。并认为在进行多样性排序时 ,Patil和Taillie的“右尾和”方法应属首选 ,因为只需计算有限个数值 ,并且该方法判断了群落内多样性的高低。其次 ,Hulbert_Smith_Grassle的方法也值得推荐 ,因为该方法有直观而明确的意义 ,它是一个随机样本中期望包含的物种数目。作为实例 ,还将这些方法应用于北京东灵山地区的 3个森林群落多样性的比较     

生态系统多功能性的测度方法

生物多样性与生态系统多功能性(biodiversity and ecosystem multifunctionality, BEMF)之间的关系是目前生态学研究的一个热点, 其中, 生态系统多功能性(EMF)的测度方法是研究该问题的技术关键。由于缺乏统一的认识, 目前存在多个多功能性的测度方法, 这使人们对生物多样性与生态系统多功能性之间关系的理解复杂化。本文介绍了国际上常用的单功能法、功能-物种替代法、平均值法、单阈值法、多阈值法、直系同源基因法和多元模型法的原理及其特点, 并对其中较难理解的多阈值法进行了举例说明, 希望能对理解EMF的测度方法有所帮助。本文按不同的EMF测度方法对已发表的有关文章进行了归类, 以期帮助读者更好地选择EMF的测度方法。由于缺乏相对统一的、代表各个层次的生态系统功能的测度方法, 导致不同的研究结果难以相互比较, 严重限制了生物多样性与生态系统多功能性研究的发展; 所以, 研发新的、具有普遍适用性的EMF测度方法已成为当务之急。     

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.