物种累积曲线及其应用

在生物多样性和群落调查中,物种累积曲线被广泛用于抽样量充分性的判断以及物种丰富度估计。然而该方法在国内却很不常见,致使相关研究无法保证科学的抽样。本文介绍了如何运用EstimateS软件计算物种累积曲线,并通过Excel绘图功能绘制曲线,以期提高生物多样性和群落调查中抽样的科学性。     

紫胶虫蜜露对地表蚂蚁多样性的影响

2009年12月至2010年5月,采用陷阱法在云南省墨江县雅邑乡调查了紫胶林地表蚂蚁群落多样性,分析了紫胶虫蜜露对地表蚂蚁多样性的影响.结果表明:紫胶虫蜜露资源的有无及变动对地表蚂蚁群落物种组成、多度及多样性均产生影响.在紫胶林样地共采集蚂蚁标本4953头,隶属5亚科23属34种,在对照样地共采集蚂蚁标本2416头,隶属5亚科20属30种;紫胶林地表蚂蚁相对多度、物种丰富度(S)及ACE估计值均高于对照样地,地表蚂蚁常见种和指示种均与对照样地不同,表明放养紫胶虫改变了地表蚂蚁群落结构;紫胶虫成虫期蜜露分泌量高于幼虫期,其地表蚂蚁相对多度、S及ACE估计值也高于幼虫期,且两阶段的蚂蚁常见种和指示种显著不同.     

喜马拉雅山错那段不同海拔梯度蚂蚁多样性

为了揭示喜马拉雅山不同海拔梯度蚂蚁的多样性规律,采用样地调查法研究了喜马拉雅山错那段北坡、南坡和山间谷地的蚂蚁群落.共采集蚂蚁标本7516头,隶属于2亚科、5属、7种.利用EstimateS 9.1.0程序对该地区蚂蚁物种丰富度进行估计并绘制物种累计曲线,结果表明错那段的蚂蚁物种实际观察值等于或接近该地区蚂蚁丰富度的估...     

蚂蚁-紫胶虫兼性互利关系对蚂蚁群落多样性的影响

为了探讨蚂蚁-紫胶虫兼性互利关系对树冠上蚂蚁群落多样性的影响,作者于2009年12月至2010年5月,采用目光搜寻的方法调查了不同紫胶虫数量样地(样地Ⅰ有效枝条寄生率为60％、样地Ⅱ为30％、样地Ⅲ为10％、样地Ⅳ不放养紫胶虫)中钝叶黄檀(Dalbergia obtusifolia)树冠蚂蚁群落的多样性.结果显示,兼性互利关系能够显著提高树冠蚂蚁群落多度及物种丰富度,改变树冠上蚂蚁的群落结构;由紫胶虫数量高低导致的蜜露产量的多寡对树冠上蚂蚁的多度和群落结构均具有显著影响,但对物种丰富度无显著影响;同时紫胶虫的个体发育阶段也是影响树冠上蚂蚁多度的重要因素.本研究证明,紫胶虫对于提高树冠上蚂蚁的多样性具有显著的正面影响,紫胶林对蚂蚁多样性保护有利.     

云南橡胶林和天然次生林枯落物层蚂蚁物种多样性、群落结构差异及指示种

橡胶树Hevea brasiliensis是云南省重要的经济林木, 但对其生态服务功能尚存在争议。本研究以天然次生林为对照, 使用Winkler法对橡胶林枯落物层蚂蚁进行初步研究, 探讨橡胶林枯落物层蚂蚁的生态状况。于2012年10月和2013年4月采用Winkler袋法调查了云南省绿春县大黑山乡橡胶林和牛孔乡天然次生林枯落物层蚂蚁群落的物种多样性、 群落结构差异及指示种。结果表明： 橡胶林枯落物层蚂蚁多度（转换后）、 物种丰富度S和ACE值显著低于无干扰的天然次生林（P<0.05）; 蚂蚁多度（转换后）显著低于有干扰的天然次生林（P<0.05）, 而物种丰富度S和ACE值差异不显著。橡胶林枯落物层蚂蚁群落结构与两种天然次生林都不相似（F=3.93, df=12, P<0.01）。橡胶林中流浪种大头蚁属Pheidole的蚂蚁种类与天然次生林相比, 物种丰富度增加了100%。天然次生林枯落物层中蚂蚁指示种有3种, 分别为刘氏隆头蚁Strumigenys lewisi、 黄足厚结猛蚁Pachycondyla luteipes和女娲角腹蚁Recurvidris nuwa, 而橡胶林枯落物层中指示种仅为菱结大头蚁Pheidole nodus。枯落物层蚂蚁物种多样性与枯落物厚度呈显著正相关, 而枯落物盖度仅与蚂蚁多度（转换后）有相关性。结果说明, 橡胶林经过长期的经营管理, 生态环境趋于稳定, 对枯落物层蚂蚁群落具有一定的保护作用, 但与天然次生林相比, 蚂蚁多度（转换后）及群落结构仍显示出明显的不同。     

基于DNA条形码的物种丰富度估计: 以宿迁地区鳞翅目蛾类为例

为了探究基于DNA条形码方法量化物种多样性指标的可行性, 本研究以江苏省宿迁地区蛾类群落为例, 基于DNA条形码方法估计群落物种丰富度并绘制等级多度分布曲线(rank-abundance curves), 同时与基于传统形态学的对应指标进行比较。结果表明: (1)基于DNA条形码的物种丰富度估计与基于形态的物种丰富度估计之间没有显著差异; (2)基于形态和DNA条形码的等级多度分布曲线趋势一致, 通过K-S检测发现二者之间没有显著性差异(P > 0.05)。结果显示, 基于DNA条形码的物种丰富度估计能够在一定程度上补充基于形态学的方法, 可以尝试将其应用于蛾类群落生态学调查研究中。     

千岛湖陆桥岛屿地表蚂蚁群落物种多样性空间格局及其影响因素

为了探讨千岛湖岛屿景观参数对地表蚂蚁群落物种α和β多样性空间格局的影响, 作者分别于2017和2018年的5-8月, 采用陷阱法、凋落物分拣法和手捡法调查了千岛湖33个岛屿上的地表蚂蚁群落, 并依据食性将其划分为捕食性蚂蚁和杂食性蚂蚁。利用回归模型分析了全部蚂蚁、捕食性蚂蚁和杂食性蚂蚁群落α和β多样性与岛屿景观参数的关系。结果表明, 岛屿面积对全部蚂蚁、捕食性蚂蚁和杂食性蚂蚁的物种丰富度均有显著的正向影响, 而隔离度则无显著作用。蚂蚁群落的β多样性由空间周转组分主导。岛屿面积差对全部蚂蚁、捕食性蚂蚁和杂食性蚂蚁群落β多样性的嵌套组分有正向影响, 隔离度差只对杂食性蚂蚁的总体β多样性有正向影响。因此, 岛屿面积是影响千岛湖地表蚂蚁群落物种丰富度的主要因素, 并且岛屿面积通过嵌套组分来影响蚂蚁群落的β多样性, 表现出选择性灭绝过程。此外, 不同食性蚂蚁可能因为扩散能力的差异对岛屿景观参数产生不同的响应。     

浮游植物生物量增长模式及抽样、互补效应检验

选取我国近海18种常见浮游植物,以不同物种构建集群,试验研究不同浮游植物集群生物量随物种丰富度的增长模式,运用多因素方差分析检验集群的抽样效应,并分别采用超产分析、相对产量之和分析、子集分析法,检验集群内的生态位互补效应.结果表明:集群生物量随物种丰富度的增长模式不是单一的,当物种数<5时,集群生物量随物种丰富度增加而增大,当物种数>5时,集群生物量与物种丰富度之间无明显规律性;集群内存在较强的互补效应,随物种丰富度的增加呈近似"钟型"曲线变化;集群在生长稳定期存在抽样效应.     

滇东南地区的蚂蚁物种多样性

为了全面揭示云南蚂蚁多样性规律,采用样地调查法研究了滇东南地区的蚂蚁物种多样性。结果表明:在滇东南地区5个垂直带共采获蚂蚁7亚科57属202种;各样地蚂蚁群落主要指标为:物种数目6～49种(平均24种),个体密度0.7～5 943.6头/m~2(平均560.5头/m~2),多样性指数0.1693～2.6382(平均1.6574),均匀度指数0.0771～0.8022(平均0.5468),优势度指数0.0012～0.9031(平均0.2733);蚂蚁群落间相似性系数0.0333～0.3810,处于极不相似至中等不相似水平。结论认为,滇东南地区栖息着丰富的蚂蚁种类,在生态系统功能和生物多样性保护中具有重要价值。垂直带上蚂蚁物种的丰富度和多样性主要受气温制约,具体表现为纬度和海拔对蚂蚁群落的影响。该地区蚂蚁群落主要指标普遍表现出多域效应现象,除了地形和森林结构因素外,主要受到人类干扰影响,应当结合天然林保护工程对该地区蚂蚁群落加以保护,以便充分发挥其生态功能。     

应用中性理论分析局域群落中的物种多样性及稳定性

如何解释群落中物种的丰富与稀少,并对物种多样性和群落稳定性进行合理的量化评价是群落生态学研究中的一个热点问题。20世纪中期,MacArthur将影响自然群落稳定性的因素归结为物种数量多少以及物种间相互作用的大小,20世纪末Doak等学者提出群落的容纳能力和物种间的维持机制是决定群落稳定性的关键因素。同时对群落结构及物种间维持机制的研究也有了新的突破,Hubbell提出"生物多样性与生物地理学统一的中性理论(Unified Neutral Theory of Biodiversity and Biogeography)"为群落生态学研究提供了新的思路和方法。从群落中性理论的基本假设出发,对Hubbell中性理论中局域群落的物种多度动态模型进行分析,归纳得出群落中性理论中物种多样性与群落稳定性之间的量化关系。封闭的局域群落中,出现物种灭绝或单物种独占的时间与群落大小及物种相对多度成正比,物种多样性程度的增加可延长物种灭绝或独占的时间;开放的局域群落中,物种多度期望值与局域群落大小、物种在集合群落中的物种相对多度成正比,周围群落中物种的灭绝会引起局域群落中相应物种的灭绝,最终导致整个生态群落物种多样性的降低;群落中物种多度的方差与局域群落大小、迁移率、物种在集合群落中的物种相对多度相关,局域群落物种多度的波动幅度随着群落间生态隔离的减弱或物种多样性程度的增加而减小。由此,集合群落物种多样性是影响局域群落物种多样性的重要因素,生态隔离程度的减弱及物种多样性的增加都将增强群落的稳定性。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.