沿海蝗区东亚飞蝗(Locusta migratoria manilensis)产卵场所选择的Logistic回归模型

以沿海蝗区南大港水库为研究区域,通过2002和2003两年野外450,50m规则栅格取样获取东亚飞蝗卵块、植物种类及其密度、土壤特性如含盐量、5cm含水量、pH、有机质及地形（阴坡和阳坡）等数据,采用多元Logistic回归模型,运用SAS软件筛选出与飞蝗产卵场所选择密切相关的变量,建立用于预测飞蝗产卵场所选择的Logistic回归模型。结果表明用植株密度（veg—d）和土壤含水量（water）所组建的模型能较好地预测飞蝗产卵选择,log（P（Y=1）/1-P（Y=1））=21．63-76.23/water-5．43log（water）-0．86（veg_d）。利用拟合优度（Goodness of fit）、预测准确性（Predictive accuracy）及模型x^2统计（Model chi—square statistic）等指标对模型进行评价的结果表明,所组建的用于预测飞蝗产卵场所选择的Logistic回归模型是可靠的,且能较好地预测事件是否发生。研究结果为区域蝗灾早期预警提供了科学依据和方法,对今后预测飞蝗产卵地点选择及防治决策有较高的实用性和应用价值。     

沿海蝗区东亚飞蝗产卵选择的适应性

以沿海蝗区南大港水库为研究区域,通过2年野外调查旨在掌握东亚飞蝗Locustamigratoriamanilensis(Meyen)产卵场所的选择。结果表明,飞蝗产卵适宜的植被覆盖度、土壤含盐量和土壤5cm含水量分别为0~30%、0.09%~1.99%和10.0%~20.0%,当植被覆盖度>70%,土壤含水量>30%或含盐量>3%时,不再适合飞蝗产卵。土壤有机质和pH值不是影响飞蝗产卵选择的主要因素。与20世纪50年代的研究结果相比,飞蝗产卵时对土壤含水量和含盐量的耐受范围拓宽,对环境的适应能力增强。     

白洋淀蝗区东亚飞蝗的分布与土壤的关系研究

从土壤的质地、含水量、pH值和含盐量等方面 ,研究了白洋淀东亚飞蝗Locustamigratoriamanilensis(Meyen)蝗区的土壤状况 ;并结合实地考察的样点处蝗虫密度情况 ,研究了蝗虫不同密度区土壤之间的差异。结果表明 ,研究区蝗虫密度在 3 0头 m2 以上的地区 ,土壤质地为粉砂壤土 ,土壤pH值为7 2 6～ 8 1 2 ,土壤含盐量为 0 0 67%～ 0 2 0 7%。粉砂壤土中 ,砂粒含量较多、粗粉粒含量较少的地方 ,是东亚飞蝗比较理想的生存与活动场所 ;土壤含水量偏高、呈弱碱性的地方 ,适于东亚飞蝗的生存和活动。在研究区 ,土壤含盐量差异对东亚飞蝗的密度分布没有明显的影响。     

基于GIS和GS的东亚飞蝗卵块空间格局的研究

本文以沿渤海蝗区东亚飞蝗Locusta migratoria manilensis (Meyen) 越冬卵块为研究对象,野外采用450 m和50 m规则栅格取样,包括卵量、植被覆盖度、土壤含水量、含盐量、土壤pH和有机质等,利用地统计学方法,在GIS平台下,分析研究区域内影响蝗虫产卵选择的环境因子、蝗虫卵块的空间异质性及分布格局。结果表明, 植被覆盖度、土壤含盐量和土壤含水量在有卵和无卵的环境中存在极显著的差异,飞蝗产卵时最适宜的植被覆盖度、土壤含水量和盐度范围分别为0～30%、10.1%～20.0%和0.09%～1.99%,且当小环境植被覆盖度>50%、土壤含水量>30%或含盐量>3%时,飞蝗不再选择产卵。蝗虫卵块具有高度空间异质性,其空间自相关范围平均为390 m且呈斑块、聚集分布,蝗虫卵块变异函数曲线为球状模型。利用块段克立格法进行空间局部插值,得到研究区域卵块的空间分布格局图,可较准确地描述飞蝗卵块在研究区域内的空间分布、形状、地理位置及相对位置。研究结果可为地面卵块抽样调查、实时跟踪蝗卵胚胎发育进程、确定蝗灾早期发生点、片防治区域及蝗灾早期遥感预警提供科学依据。     

基于沿海蝗区飞蝗卵块分布格局的土壤空间异质性

以沿海蝗区南大港水库为研究区域,通过连续2a野外450m,50m规则栅格取样,利用地统计学方法,在GIS平台下,分析东亚飞蝗卵块分布格局与土壤空间异质性的研究,结果表明：（1）飞蝗卵块呈斑块、聚集分布,并具有明显的空间异质性,其空间自相关范围为390m,且主要分布在南大港水库的中部和东部,少数分布在南部,而在西部和北部地块几乎没有卵的分布。（2）研究区域内土壤含盐量和5cm含水量由空间自相关引起的空间异质性分别占总空间异质性的76.15%、78.04%,即表现出较强的空间相关性,空间自相关范围分别为594m,621m,土壤有机质和pH值具有中等强度的空间相关性,由空间自相关引起的空间变异分别为61.85%和57.19%,空间变异尺度分别为1014m,1368m。（3）研究区域内卵块主要集中在土壤含盐量较低（〈1.9%）、含水量适中（10.1%~29.9%）的中部和东部地块,而在土壤含水量较高（〉30%）的西部和盐分过重（〉3%）的北部几乎没有卵块的分布。即在一定程度上,蝗区土壤理化特性的空间异质决定了飞蝗卵块的空间分布特点。（4）卵块和土壤理化特性的空间格局图不仅为野外抽样调查、蝗灾预测预报及其防治提供科学依据,而且对蝗区环境改造具有重要指导作用。     

东亚飞蝗选择栖息高度影响因素的研究

为明确东亚飞蝗Locusta migratoria manilensis对植物群落的利用特征,采用自然生境中罩笼的方法,观察东亚飞蝗对栖息高度的选择行为,分析发生代数、种群密度、调查时间以及环境温湿度对东亚飞蝗栖息高度选择的影响。结果表明:东亚飞蝗夏蝗偏好栖息在0～20 cm,秋蝗偏好栖息在80 cm。在食物充足的条件下,当蝗蝻密度d≤20头/m~2时,东亚飞蝗偏好栖息在植株中上部,以80 cm的蝗虫数量比最大;种群密度d=100头/m~2,飞蝗偏好栖息在植株较低位置,以0～20 cm的蝗虫数量比最大。东亚飞蝗在日出之前和日落之后偏好栖息在植株中上部;在12∶00和16∶00这两个时间段偏好选择栖息在植株中下部。选择栖息在0～20、40～60和80 cm这3个高度的东亚飞蝗数量百分比与环境温度呈负相关,但是与环境湿度呈显著的正相关(P0.05)。这说明随着温度的降低或湿度的增加,飞蝗偏好栖息在这3个位置。     

李氏大足蝗线粒体全基因组序列分析

采用长距PCR 扩增及保守引物步移法测定并注释了李氏大足蝗( Aeropus licenti Chang)的线粒体基因组全序列。结果表明,李氏大足蝗的线粒体基因组全长15 597 bp,A+T 含量为74.8%,37个基因位置与飞蝗的一致,基因间隔序列共计17处105 bp,间隔长度从1～21 bp不等;有10对基因间存在58 bp重叠,重叠碱基数在1～17 bp之间。13个蛋白质编码基因中找到4种可能的起始密码子;有12个基因在基因3'端找到完全的TAA或TAG 终止密码子,只有ND5基因终止密码子为不完整的T。除tRNA^Ser（AGN）外,其余21个tRNA基因的二级结构均属典型的三叶草结构。tRNA^Ser（AGN）的DHU臂缺失,在相应的位置上只形成一个环。预测的lrRNA二级结构总共有6个结构域（结构域Ⅲ缺失）,47个茎环结构;预测的srRNA的二级结构包含3个结构域,31个茎环结构。A+T 丰富区长度为712 bp。     

蝗卵的研究,Ⅰ.亚洲飞蝗蝗卵孵育期中胚胎形态变化的观察及野外蝗卵胚胎发育期的调查

一.引言 亚洲飞蝗(Locusta migratoria manilensis Meyen)(以下简称飞蝗)在我国沿海诸省每年一般发生两代。根据在洪泽湖与微山湖蝗区观察的结果,夏蝗在6月下旬和7月上旬产卵,至同年7月中、下旬孵化;秋蝗在9月上、中旬产卵,到次年6月上旬孵化。越冬蝗卵在土中停留8个月左右的时间,这使它们有充分的机会去领受当地环境因素如寒冷、干,湿、天敌等的作用,从而左右次年飞蝗发生时间     

氟虫脲对东亚飞蝗和中华稻蝗几丁质合成酶基因表达的影响

为了探讨氟虫脲可能的作用靶标及毒性机制, 本研究以重要农业害虫东亚飞蝗Locusta migratoria manilensis (Meyen)和中华稻蝗Oxya chinensis (Thunberg)为材料, 采用简并引物扩增中华稻蝗几丁质合成酶1基因（OcCHS1）的部分cDNA序列; 以氟虫脲浸渍法处理2龄中期中华稻蝗及1, 2和3龄东亚飞蝗若虫为处理组, 丙酮处理为对照组, 使用RT-PCR和实时荧光定量PCR方法分析氟虫脲对蝗虫几丁质合成酶基因mRNA表达的影响。结果获得的OcCHS1部分cDNA序列, 其长度为312 bp, 编码104个氨基酸, GenBank登录号为HM214491, 与东亚飞蝗几丁质合成酶1基因（LmCHS1）在氨基酸水平上相似度达95％。RT-PCR结果显示, 处理组几丁质合成酶1扩增带均强于对照组。实时荧光定量PCR结果表明: 与对照组相比, 处理组中华稻蝗2龄中期若虫OcCHS1 mRNA表达提高了1.02倍, 东亚飞蝗1, 2, 3龄若虫LmCHS1 mRNA表达分别提高了34%, 82%和89%, 差异显著（P<0.05）。分析基因表达提高的原因是几丁质合成受阻后基因表达水平的一种代偿性增加, 由此推测几丁质合成酶可能是氟虫脲作用的靶标之一。     

不同温度、土壤含水量及日光照时数对棉露尾甲虫(Haptoncus luteolus (Erichson))生长发育的影响

在5,10,15,20,30 ℃等5种温度、10%,20%,30%等3种土壤含水量和8,12,16 h等3种日光照时数共45个处理组合条件下,以丝瓜花作为饲料研究了3个因素对棉露尾甲生长发育的联合作用。结果表明：适合于卵生长发育的处理组合为25~35 ℃、10~15%和12~16 h,其中最佳处理组合为30 ℃、10%和12 h,在此组合条件下,卵发育历期为0.8 d,孵化率为93.3%;适合于幼虫及蛹生长发育的处理组合为：25~30 ℃、10~15%和12~16 h,其中最佳处理组合分别为30 ℃、10%、12 h和30 ℃、10%、8 h,在此组合条件下,幼虫历期、存活率和蛹历期、羽化率分别为5.0 d、85.7%和2.2 d、83.3%。在三元二次回归模型中,卵、幼虫、蛹和整个未成熟期（卵至蛹的历期）发育进度最快时的处理组合分别为27.5 ℃、10%、8 h,30 ℃、20%、12 h,32.5 ℃、10%、16 h和30 ℃、10%、16 h;此时理论最短历期分别为0.8、4.4、1.4 d和7.3 d。     

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.