啮齿动物对不同大小和种皮特征种子的取食和搬运

在宁夏六盘山区的辽东栎灌丛,以不同大小的辽东栎种子、野李和华山松种子为材料,研究了种子大小和种皮特征对啮齿动物取食和搬运行为的影响.结果表明:辽东栎小种子和华山松种子的就地取食率均显著高于辽东栎大种子和野李种子;具有厚而坚硬种皮(内果皮)的野李种子被啮齿动物搬运后的取食率和贮藏率均最高.辽东栎大种子被啮齿动物搬运后取食的距离最大(3.10 m),被搬运后贮藏的距离(6.48 m)显著大于其他类型种子.除野李种子外,其他3种类型种子的单个种子取食点都在80％以上,所有种子的单个种子贮藏点都在90％以上,含2个以上种子的取食点和贮藏点较少.较高比例的华山松种子在灌丛基部和洞穴以外的其他环境被取食,其他3种类型种子被啮齿动物搬运后主要集中在灌丛基部和洞穴中取食;种皮(内果皮)厚而坚硬的种子以土壤埋藏方式贮藏的比例偏高.     

河南省啮齿动物地理分布的聚类研究

路纪琪等[1 ]对河南省啮齿动物区系与区划进行了研究 ,把河南省已知的 32种啮齿动物区系划分为豫西北太行山地森林省、豫西黄土台地农作省、豫东豫北平原及南阳盆地农作省、豫西伏牛山地森林省、淮南冲积平原农作省和豫南桐柏 大别山地森林省共 6个动物地理省。因为毛耳飞鼠(Ｂｅｌｏｍｙｓ ｐｅａｒｓｏｎｉｉ )、中华鼢鼠(Ｍｙｏｓｐａｌａｘ ｆｏｎｔａｎｅｒｉ)、针毛鼠 (Ｒａｔｔｕｓｆｕｌｖｅｓｃｅｎｓ) 3种动物尚无标本考证 ,故本文所列河南省啮齿动物计 2 9种。另据马勇等[2 ]研究 ,认为应恢复绒鼠平属 (Ｃａｒｙｏｍｙｓ)的分…     

内蒙古半荒漠与荒漠区的啮齿动物群落

内蒙古广阔的半荒漠与荒漠区属于典型的大陆干旱区和极干旱区,东西界线基本与气候湿润系数0.2-0.05相吻合,包括了内蒙古境内的温性荒漠草原、温性草原化荒漠和典型荒漠的各类草地。1988-1993年和1998-2003年,在约380000km2范围内,根据地带性植被分布及其地形、地貌、土壤的特征,野外设置317个调查样地,采用铗日法调查啮齿动物群落的分布特征,共布放有效铗日157702个,捕获啮齿动物37种,选用其中的23种主要啮齿动物构成“样方-种多度(捕获率)”原始数据矩阵(23×317),应用快速聚类方法对该区域内啮齿动物群落进行分类,在此基础上采用GIS技术应用ArcView3.2软件,将啮齿动物的捕获量信息在1999-2000年TM卫星影像图上进行叠加,结果表明该地区啮齿动物地带性群落可分为9个。GIS技术分析得出的该区域内啮齿动物地带性群落分布图,很好地将植被的信息和生境中主要啮齿动物分布的信息同时合成反映出来,明确了啮齿动物地带性群落分布的区域和特征,可为区域性啮齿动物综合治理提供科学依据。     

安徽省啮齿动物的区系分布和地理区划

安徽省啮齿动物区系情况,解放前Allen(1940)、Gee(1930)、Tate(1947),阿部余四男(1944)曾有过一些零星报道,解放后盛和林等(1963)、王岐山等(1966)、黄文几等(1978)也进行过调查,但就啮齿动物区系而言,尚缺乏完整的系统材料。我站从1958年起,开始对本省啮齿动物进行调查,重点主要在平原及丘陵地带,对皖南及大别山区调查较少。近年来,我们在皖南山区的祁门、休宁、绩溪、黄山、宁国、宣城、泾县、歙县、青阳及大别山区的金寨、霍山、岳西、潜山、舒城等山地进行了补点调查。现将调查结果,结合以往的工作和文献作初步整理,并就啮齿动物的地理分布和优势种,综合自然地理等因素进行啮齿动物的地理区划。     

黑河流域中游地区荒漠-绿洲景观区啮齿动物群落结构

2005年4–5月和9月对黑河流域中游地区荒漠-绿洲景观区不同生境中啮齿动物群落结构进行了研究。在甘肃省张掖市高台县黑泉乡选择流动沙丘、含砾沙漠、固定沙地、荒漠灌丛、防护林带、灌耕草地、灌耕农田和河岸草地等8种代表性生境,采用活捕法(4,800铗日)共捕获啮齿动物254只,隶属于3科8属9种。利用捕获记录计算了群落结构特征指数,进一步利用Pearson相关系数考察了不同生境啮齿动物群落的相似性,并在此基础上对不同生境的啮齿动物群落作了聚类分析。群落结构特征指数表明,啮齿动物物种多样性(用Shannon-Wiener指数测度)在灌耕草地中最低(0.6859),在固定沙地中最高(1.7036);物种均匀度(用Pielou均匀度指数测度)在流动沙丘中最低(0.6531),在河岸草地中最高(1.0000)。聚类分析结果显示,研究区啮齿动物群落可以分成荒漠型群落和绿洲型群落两大类。三趾跳鼠(Dipussagitta)在荒漠型生境中密度较高,总体上具有优势地位,尤其是在流动沙丘生境中占据绝对优势;黑线仓鼠(Cricetulusbarabensis)在植被较好的绿洲型生境中占据优势地位,但在流动沙丘外的其他荒漠型生境中也有发现。除五趾跳鼠(Allactagasibirica)外,其他种类的跳鼠只在荒漠型生境中发现。本次调查没有在防护林内部生境中捕获啮齿动物,但在林缘区域仍有捕获记录。啮齿动物群落物种多样性指数与捕获率间无显著关联(r=0.240,P=0.566)。本研究提示人为干扰可能对维持研究区域的啮齿动物多样性有积极意义。     

宁夏贺兰山东麓荒漠草原区地衣的物种多样性研究

地衣是宁夏贺兰山东麓荒漠草原区一类重要的生物资源,地衣结皮的形成为该区域景观的稳定作出了重要的贡献。该研究于2014~2019年在贺兰山东麓荒漠草原区开展了地衣的野外调查,利用表型特征和DNA序列分析且对采集的500余份标本进行了物种的鉴定,并分析了其物种组成及地理成分。结果显示：(1)共鉴定地衣19科41属74种,其中中国新记录25种,新种2个(待发表),新记录属11个,宁夏新记录56种。(2)研究区地衣物种区系地理成分以北温带成分为主(33.78%),其他主要区系成分包括欧亚成分和世界广布成分等,具有明显的北温带成分区系特征。(3)研究区地衣以壳状和鳞状地衣为主(81.1%),生长型体现了地衣对当地气候条件的适应特性。实地调查发现宁夏贺兰山东麓荒漠草原区地衣的生存环境非常脆弱。该研究结果有助于提高对该区域地衣物种多样性的认识并促进其保护。     

典型草原啮齿动物密度与牧草损失量的关系

研究啮齿动物密度对牧草损失量的关系,对于计算草地经济损害水平至关重要,可以为草地畜牧业管理决策提供指导。本研究于2012 - 2016 年,在锡林郭勒典型草原(东乌珠穆沁旗),应用标志重捕法和样方法对啮齿动物密度以及9 月份植物地上生物量进行调查,用啮齿动物密度及其日食量来估算鼠类对牧草的损害程度,确定牧草损失量。研究结果表明:(1)啮齿动物密度与牧草损失量的最佳拟合曲线是三参数S 型曲线,为:Loss = k/(1+e ^{a - rdensity});(2)当啮齿动物密度>906 个标准鼠单位/hm² 时,牧草产量发生最大损失(牧草产量损失比=23.30% );(3)根据所拟合的曲线,得出该类型草地啮齿动物对牧草损害的危害阈值为174 个标准鼠单位/hm² 。     

不同干扰下荒漠啮齿动物群落多样性的多尺度分析

尺度问题是生态学的核心问题。本文将荒漠啮齿动物群落主要特征参数Shannon-Wiener多样性指数作为信息,来探究其在人为干扰下对尺度变化的响应,目的是为了揭示不同干扰条件下荒漠区啮齿动物群落多样性随尺度变化的趋势,为动物群落格局—过程研究的尺度推绎提供生态学基础。2003~2008年每年7月,在内蒙古阿拉善荒漠禁牧、轮牧、过牧和开垦4种不同干扰生境中,选择了1.25hm2,2.5hm2,5hm2和10hm2等4个空间尺度,应用铗日法统计样地中的啮齿动物群落种数及各物种的捕获数据,计算Shannon-Wiener多样性指数,将其作为原始信号进行小波分解。研究结果表明：在荒漠区≤10hm2内,除过牧区外,在其他干扰类型中啮齿动物群落多样性随空间尺度增加均呈上升趋势。啮齿动物群落多样性的原始信号中存在规则的周期性干扰,这种干扰可能是由群落的年际波动造成的。在4种尺度下,各干扰区啮齿动物群落多样性除在开垦区未表现出明显周期外,其余干扰区各自均具有相同的周期：轮牧区4年,禁牧区3年,过牧区2年。荒漠区4种干扰类型中随着空间尺度的增加啮齿动物群落多样性变动幅度减小,抗干扰能力逐渐增强。但不同干扰中啮齿动物多样性的变动幅度和抗干扰能力是不同的。禁牧区与开垦区的啮齿动物多样性在≤2.5hm2范围内较易受到扰动;过牧区在≤5hm2的范围内较不稳定;轮牧区在整个10hm2范围内都易受到扰动。     

浙江西天目山的啮齿动物

我们于1963年5-7月,在浙江省西天目山的4个地区,对啮齿动物分布进行调查,为今后研究该地鼠类群落演替作对照,兹将调查结果简报如下: 据1525个铗日统计,共得啮齿动物8种;长吻松鼠(Dremomys pernyi),大仓鼠(Cricetulustriton),黑腹绒鼠(Eothenomys melanogaster),黑线姬鼠(Apodemus agrarius)黄胸鼠(Ra-ttus flavipectus),社鼠(R.confucianus),青毛鼠(R.bowersi),小泡巨鼠(R.edwardsi)。见表1。     

我国长江中下游以南地区啮齿动物的组成和分布

啮齿动物在哺乳动物中是一大类群,与人关系密切,广布于世界各地,据查到目前为止我国南方的八个省区,有85种之多,约占全国种数的53％,它们在自然界以摄取植物性食物为生(一级消费者),然后把自身供给肉食或杂食性动物(二级消费者)为食,在自然生态平衡中起着积极的作用。但其中有些种类对人工垦植的农、林业生产有害,还有少数种类是病原体的携带者,传播疾病,危害人畜健康,为此研究啮齿动物的区系组成,地理分布有其重要意义。现就我室自1957年以来在广西、广东、福建、湖     

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.