二化螟越冬幼虫空间分布图式的地理统计学分析

利用地理统计学的方法,对二化螟直冬幼虫的田间全查数据进行分析,通过全方位上的半方差图和Ｋｒｉｇｉｎｇ估计后的空间分布。结合二化螟的生物学特性和以往的概率拟合确定,该田块的二化螟越冬幼虫在０．２－０．３ｍ的扩散中心的四周扩散,在形成１．８－２．０ｍ的聚集区,各聚集区间则为均匀２,同时对未取样点的值进行相应的估计。     

褐梗天牛幼虫和成虫空间分布的地统计学研究

褐梗天牛(Arhopalus rusticus Linnaeus)是一种对松、杉、柏等林木危害非常严重的蛀干害虫,主要危害针叶树的衰弱木以及火灾后的枯立木,是继松褐天牛之后携带拟松材线虫能力最强的蛀干害虫。为了更好地控制其危害,深入地研究其种群空间格局,运用地统计学方法分析了3块受害程度不同的油松林内褐梗天牛幼虫和成虫的空间分布特性。结果表明:3种受害程度不同的林分内,褐梗天牛的危害具有显著差异,轻度受害林分内有虫株率为30.8%,中度受害林分内有虫株率为44.3%,而重度受害林分内高达78.3%。根据变异函数曲线图分析得知:轻度受害林、中度受害林和重度受害林内褐梗天牛幼虫种群空间分布最优拟合模型分别为高斯模型、高斯模型和指数模型,成虫的种群空间分布最优拟合模型均为线性模型。在3种林分中褐梗天牛幼虫数量具有明显的空间依赖性,轻度受害林、中度受害林和重度受害林内幼虫数量的空间依赖范围分别是19.10、11.97、61.98m,其空间连续性强度分别是0.646、0.784和0.500;成虫的空间依赖范围分别是43.08、43.23、44.17m,其空间连续性强度分别是0.044、0.021和0.171,但其成虫的数量在空间呈随机分布,没有表现出空间依赖性。根据垂直分布图分析得出:褐梗天牛幼虫和成虫在油松上主要集中聚集在某个高,然后随着高度增加密度降低,随着高度接近地面密度也降低。用Kriging插值法生成的空间分布图显示幼虫在空间分布上具有明显的聚集性,其聚集中心主要集中在林地中心,由林地中心株向整个林地扩散,而成虫则表现为随机分布。     

管氏肿腿蜂的寄生与产卵行为研究

本文研究了管氏肿腿蜂在双条杉天牛幼虫上的产卵行为,其行为过程包括聚集、检验、蛰刺、清理寄主、取食、游走、产卵、休息.在不同寄主上,管氏肿腿蜂卵的分布存在差异:在桑虎天牛幼虫上卵大部分横向排列在寄主体表,两侧和背腹面卵的数量差异极显著;在黄粉虫幼虫体表卵的分布是随机的,卵的排列方向无规律性.从接蜂到产卵,有产卵经验的雌蜂所需的时间显著短于无产卵经验的雌蜂.     

棉铃虫卵和龟纹瓢虫,中华草蛉分布格局的关系研究

通过田间调查,研究了棉铃虫卵和龟纹瓢虫、中华草蛉空间分布的关系．研究表明,棉铃虫卵和龟纹瓢虫、中华草蛉在棉株垂直各层上的数量间相关系数６ 月分别为０ ．５６９６ 、０ ．８６２０ ,７ 月为０ ．８３００ 、０ ．９２８２ ,８ 月为０ ．９０８３ 、０ ．８２０１ ,除６ 月龟纹瓢虫外,其余皆达显著或极显著水平;垂直格局上棉铃虫卵和龟纹瓢虫扩散系数和久野指数间相关系数分别为０ ．８２１１ 、０ ．７７９１ ,皆达极显著水平;水平格局上棉铃虫卵和中华草蛉扩散系数和久野指数间相关系数分别为０ ．７９２５ 、０ ．５２２８ ,分别达极显著和显著水平．     

对虾的不同发育阶段对有机磷农药的敏感性及其机理初探

对硫磷、甲基异柳磷和久效磷对中国对虾无节幼虫、蚤状幼虫、糠虾幼虫、仔虾的２４ｈＬＣ５０分别为６．０、４．０、３．８、１８×１０－３ｍｇ·Ｌ－１;８．０、３．５、３．５、３０×１０－３ｍｇ·Ｌ－１;２４、２４、２４、０．９ｍｇ·Ｌ－１;敌敌畏均为４８×１０－３ｍｇ·Ｌ－１;对硫磷对南美白对虾为８．６、８．２、８．０、２．０×１０－３ｍｇ·Ｌ－１．研究结果表明,对虾的幼虫前期对硫代磷酸酯类农药的抗性强,仔虾及以后各期抗性弱,而各幼虫期对磷酸酯类农药的敏感性基本相同．     

海南岛吊罗山山地雨林物种多样性

在海南岛吊罗山热带山地雨林设置两５０００ｍ＾２的样地,分别从物种多样性指数,种－多度曲线,空间格局多样性,时间格局多样性,组成格局多样性对其进行了研究。结果表明海南岛吊罗山山地雨林物种多样性指数Ｓｈａｎｎｏｎ－Ｗｅａｖｅｒ和Ｓｉｍｐｓｏｎ指数分别为４．１９５和０．０２１,均匀度为０．８８０和２．９６２。     

皮下接种松墨天牛卵及幼虫致死松树的研究

为了探明松墨天牛MonochamusalternatusHope直接致死松树的作用 ,作者采用在健康松树皮下接入松墨天牛卵或初孵幼虫方法做了试验和观察。结果表明 ,接入卵或初孵幼虫的松树平均枯死率为41 . 7%。松树枯死取决于松墨天牛幼虫取食时对松树韧皮部的破坏程度。每株接入 5个单位 (1单位指1粒卵或条初孵幼虫 ) ,松树枯死率达 85. 7% ;接入 1个单位 ,枯死率为 1 0 %。初步结论是 ,松墨天牛是引起松树枯死的主要原因之一 ;大力防治松墨天牛是保护我国松林的关键。     

深圳福田白骨壤群落Cr,Ni,Mn的累积及分布

探讨了深圳福田自然保护区白骨壤红树林对Ｃｒ、Ｎｉ、Ｍｎ的吸收、累积及分布．结果表明,该林地土壤Ｃｒ、Ｎｉ、Ｍｎ含量从底层至表层逐步提高;表层（０～３０ｃｍ深）３种元素含量分别为７．９７、２５．０和５３７μｇ·ｇ－１,贮量分别为１０９９．８６、３４５０．００和７４１０６．００ｍｇ·ｍ－２．白骨壤植物各部位Ｃｒ、Ｎｉ、Ｍｎ含量范围分别为０．２８～０．７５、０．４３～７．６５和２５～１５５２μｇ·ｇ－１;植物对表层土壤加权平均富集系数为Ｍｎ＞Ｎｉ≈Ｃｒ．该群落Ｃｒ、Ｎｉ、Ｍｎ的现存累积量分别为６．０６、２０．７６和１６３１．１７ｍｇ·ｍ－２,年净存留累积量分别为０．４３、１．４３和１０７．９８ｍｇ·ｍ－２;林地残留物相应元素储量分别为Ｃｒ７８．００μｇ·ｍ－２、Ｎｉ１５３６．３３μｇ·ｍ－２和Ｍｎ４０５．５４ｍｇ·ｍ－２．该林区３种不同类型群落叶层Ｃｒ、Ｎｉ现存累积量为白骨壤林＞桐花树林＞秋茄林,Ｍｎ为秋茄林＞白骨壤林＞桐花树林．     

栗山天牛天敌花绒寄甲在栎林中的种群保持机制

花绒寄甲(Dastarcus helophoroides)(鞘翅目:寄甲科Bothrideridae)是寄生栗山天牛(Massicus raddei)中老龄幼虫和蛹的重要天敌,但其寄主栗山天牛世代周期长(3年1代)、发育比较整齐,不利于寄生性天敌种群数量的稳定.为了解利用花绒寄甲防治栗山天牛后,其种群能否在栎树林间长期保持较高的种群数量,达到持续控制栗山天牛的防治效果,调查研究了花绒寄甲在栎树林间的转主寄主和种群保持机制.结果表明,在东北辽东栎树干和树枝上除了栗山天牛外,还有其他8种天牛危害:双簇天牛(Moechotypa diphysis)、四点象天牛(Mesosa myops)、中华薄翅锯天牛(Megopis sinica)、锯天牛(Prionus insularis)、双带粒翅天牛(Lamiomimus gottschei)、八字绿虎天牛(Chlorophorus tohokensis)、日本绿虎天牛(C.japonicus)和拟蜡天牛(Stenygrinumquadrinotatum).其中以栗山天牛、双簇天牛、四点象天牛和拟蜡天牛数量较多,而花绒寄甲在辽东栎树干上的垂直分布与栗山天牛、双簇天牛和四点象天牛的垂直分布重叠较多.室内研究表明,花绒寄甲对四点象天牛老熟幼虫的寄生率达到26.67％,对蛹的寄生率达到了43.33％;对双簇天牛老熟幼虫的寄生率达到20.00％,对蛹的寄生率为6.67％.对双簇天牛和四点象天牛在林间的生活史调查和研究发现,花绒寄甲可寄生的这两种天牛的中老龄幼虫和蛹,在花绒寄甲不适宜寄生的栗山天牛幼龄幼虫期大量存在,表明双簇天牛和四点象天牛是花绒寄甲在栎树林中的主要转主寄主.由于这些转主寄主的存在,花绒寄甲在不利于其寄生的栗山天牛卵期、幼龄幼虫期可转移寄生这些寄主,从而在栗山天牛危害的栎树林间保持了较高的种群数量,达到对栗山天牛长期而有效的持续控制效果.     

松褐天牛肿腿蜂对悬铃木上天牛的控制效果

释放肿腿蜂是控制天牛的环境友好型生物防治方法之一。为评价松褐天牛肿腿蜂Sclerodermus sp.对悬铃木上天牛的防治效果,首先调查明确了荆州城区危害悬铃木的天牛种类主要为光肩星天牛,其幼虫和成虫数量分别占天牛总数量93.78%和95.45%;室内测定结果显示蜂虫比2∶1、1∶1、1∶2时光肩星天牛3个龄期幼虫寄生死亡率分别为86.67%、76.30%、33.34%;野外释放寄生蜂60 d后释放点天牛虫口减退率为52.79%-81.85%。研究结果表明,人工释放松褐天牛肿腿蜂能够有效控制悬铃木上天牛种群。     

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.