中国各棉区棉铃虫滞育解除特点

试验研究了我国华南棉区、长江流域棉区、黄河流域棉区、北部特早熟棉区和西北内陆棉区棉铃虫Helicoverpa armigera(Hubner)13个地理种群的滞育解除特点。随纬度升高地理种群滞育蛹在高温下的发育时间显著延长,羽化格局趋于松散,在30℃下湖南衡阳种群和新疆哈密种群的发育时间分别为(15.6±4.9)d和(41.4±9.0)d。低温处理可明显降低长江流域以北种群的滞育历期,但对华南棉区北部种群则无明显的活化作用。湖南衡阳种群、湖北武穴种群、北京种群和新疆哈密种群活化滞育蛹的发育起点温度和有效积温分别为17.4℃和146.O日度,16.6℃和146.5日度,15.7℃和156.4日度及15.7℃和167.7日度。     

棉铃虫种群适合度研究

本试验比较了我国各棉区棉铃虫Helicoverpa armzgcra(Hubner)种群幼虫期和蛹期发育速度与温度的关系,并模拟了长江流域种群和华北种群在北京地区的发育动态。研究结果表明在20℃～30℃温区内不同地理种群之间的发育速度无明显的感温分化现象,但在自然条件下长江流域种群和华北地区种群的蛹滞育动态则有显著的区别,如湖南衡阳种群和四川简阳种群50%蛹滞育的时间较北京种群晚30d和22d。对各地理种群发育动态、北京地区气候特点和滞育蛹越冬试验结果的综合分析表明,北京地区应为棉铃虫温带生态型生态区北界,棉铃虫亚热带生态型在华北气候环境下不能完成年生活史。     

棉铃虫发育历期的地理变异

为探明棉铃虫Helicoverpa armigera Hübner不同地理种群发育历期及其地理变异,通过对棉铃虫不同地理种群在不同温度和光周期下幼虫和蛹发育历期的研究,本论文系统比较了来自中国的4个地理种群,广东广州(23.08°N,113.14°E)、江西永修(29.04°N,115.82°E)、山东泰安(36.15°N,116.59°E)、辽宁喀佐(41.34°N,120.27°E)在20℃、22℃、25℃和28℃恒温下的幼虫、非滞育蛹和滞育蛹发育历期及其与栖息地纬度的关系。结果表明,棉铃虫幼虫发育历期随栖息地纬度的升高而缩短,在25℃下,与地理纬度存在明显的负相关关系,其它温度下呈不显著的负相关关系,雌雄幼虫发育历期相似,差异不显著;在20℃下,蛹历期(包括滞育蛹和非滞育蛹)与栖息地纬度呈显著负相关,其它温度下的蛹历期与栖息地纬度呈正相关,雄蛹历期均要略长于雌蛹历期,但差异不显著。棉铃虫幼虫和蛹发育历期随着纬度的变化呈现一种渐变的趋势,存在地理变异;北方种群的幼虫发育历期较南方种群的短;适温(22℃-28℃)范围内,北方种群的非滞育蛹发育历期比南方种群的更长些;不同地理种群间滞育蛹的历期亦存在较大的差别。这些结果进一步揭示了即使在同一种类昆虫中,不同实验条件,其各个虫态发育历期的地理变异也可能不同。     

美国白蛾过冷却点的影响因子

美国白蛾是一种重要的国际检疫害虫,作为外来入侵生物在中国不断扩散蔓延。过冷却点是研究其潜在适生区重要的生理指标之一。本文研究了不同虫态、寄主树木、低温驯化时间和地理种群与过冷却点的关系。结果表明:美国白蛾不同虫态过冷却点间存在显著差异(P0.001),蛹期过冷却点最低(-15.91℃),5龄幼虫的过冷却点最高(-6.97℃),过冷却点随虫态龄期增加而升高;用悬铃木饲养的美国白蛾蛹的平均过冷却点为-16.09℃,显著低于复叶槭饲养的美国白蛾蛹的平均过冷却点-14.61℃(P=0.002);在6℃下分别驯化美国白蛾非滞育蛹24、48和72 h,美国白蛾非滞育蛹过冷却点无显著差异(P=0.846);武邑、内黄、濮阳、东营、寿光和沈阳6个不同地理种群美国白蛾蛹的过冷却点间存在极显著差异(P0.001),其中内黄地区美国白蛾过冷却点最低(-21.39℃),东营地区过冷却点最高(-15.35℃)。     

烟夜蛾滞育蛹和非滞育蛹的耐寒性

对烟夜蛾Helicoverpa assultaGuen?e不同日龄滞育蛹和非滞育蛹的过冷却点和结冰点测定结果表明,在预蛹至5日龄蛹期,过冷却点和结冰点均逐渐下降。在预蛹期和3日龄蛹期,滞育蛹的过冷却点与非滞育蛹差异不显著;5日龄蛹时,滞育蛹和非滞育蛹的过冷却点分别下降至(-15.7±1.8)℃和(-13.5±1.2)℃,结冰点分别降至(-12.7±2.7)℃和(-9.5±1.3)℃,两类蛹间的差异均达极显著水平。自然越冬后,滞育蛹的存活率显著高于非滞育蛹,在土壤不同深处越冬的蛹的存活率存在差异,距土表15cm深的蛹存活率最高。     

棉铃虫发育起点温度和有效积温的地理变异

为探明棉铃虫Helicoverpa armigera不同地理种群发育起点温度和有效积温及其地理变异,推测该虫在不同地区可能发生的代数、为预测其发育发生期的差异提供依据,从而更有效地进行该虫的综合治理。以采集自中国的4个地理种群(广东广州(23.08°N,113.14°E)、江西永修(29.04°N,115.82°E)、山东泰安(36.15°N,116.59°E)、辽宁喀佐(41.34°N,120.27°E)的幼虫在室内饲养繁育1代后为试材,采用在获得其在20℃、22℃、25℃和28℃恒温、L16∶D8的光周期条件下饲养的发育历期的基础上,比较研究这4个地理种群的幼虫、非滞育蛹和滞育蛹的发育起点温度和有效积温及其与栖息地纬度的关系。结果表明:在实验室人工饲料饲养的条件下,棉铃虫幼虫、非滞育蛹和滞育蛹发育起点温度分别为10.18℃-12.19℃、10.60℃-13.50℃、15.56℃-17.96℃,有效积温分别为254.91-300.89日度、126.21-204.43日度、181.03-363.39日度,滞育蛹的发育起点温度比非滞育蛹高3.39℃-5.50℃,其有效积温比非滞育蛹高35.56-165.89日度。这些说明棉铃虫发育起点温度和有效积温均存在明显地理变异,随栖息地纬度的升高,幼虫、非滞育蛹和滞育蛹的发育起点温度呈现逐渐下降趋势,幼虫的发育起点温度与栖息地纬度呈显著负相关关系(P0.05),其余呈不显著负相关(P0.05),而有效积温则相反,呈现上升趋势,滞育蛹有效积温与栖息地纬度升高呈显著正相关(P0.05),其余呈不显著正相关(P0.05)。     

寄主植物对棉铃虫越冬蛹抗寒能力的影响

通过对滞育蛹过冷却点的测定 ,初步明确寄主对棉铃虫Helicoverpaarmigera的越冬抗寒性有影响 ,幼虫取食棉花时产生的滞育蛹的过冷却点低于取食玉米的滞育蛹的过冷却点 ,即前者的抗寒能力高于后者 ;但用Bt棉喂养后的棉铃虫滞育蛹抗寒能力下降     

棉铃虫取食转Bt棉后蛹的抗寒力测定

在棉铃虫HelicoverpaarmigeraH櫣bner人工饲料中分别添加转Bt基因棉叶粉和常规棉叶粉饲喂幼虫,经滞育诱导后,发现2个处理间棉铃虫蛹的滞育率相似,2个处理间滞育蛹的自由水和结合水含量没有差异;但取食含Bt棉叶粉人工饲料的棉铃虫滞育蛹的过冷却点和结冰点显著高于对照组,蛹重及与抗寒性有关的脂肪和糖原含量均显著低于对照组。     

新疆棉铃虫滞育的诱导和解除

在我国各棉区,棉铃虫Helicoverpaarmi－gera（Hilbner）均以滞育蛹越冬。迄今,对该虫北京、四川简阳、豫南、苏北等地理种群的滞育诱导或解除特性均已有所研究［1-6］,从中明确了光照和温度是其滞育形成的主要影响因素,温度则对滞育解除起主导作用。本研究以新疆种群为材料,结果如下。1材料与方法1．1虫源：采自新疆阿拉尔（40．5°N）。室内在27℃左右、光照14小时下用人工饲料连续饲养[7]。1．2不同温度和光照下滞育形成情况观察：在温度22～28℃和光照9～14．5小时的组合条件下饲养幼虫,化蛹1周后,参考Phillip等（1966）的方法…     

柑桔大实蝇老熟幼虫和蛹过冷却点和结冰点的测定

为明确柑桔大实蝇Bactrocera minax (Enderlein)老熟幼虫和蛹的抗寒能力,对柑桔大实蝇老熟幼虫、滞育蛹和滞育解除蛹的过冷却点和结冰点进行了测定。结果显示,同一虫态不同个体间其过冷却点和结冰点具有不同程度的变异,但其变异范围均符合正态分布。柑桔大实蝇不同发育状态间的过冷却点和结冰点均具有显著差异,其中,已解除滞育进入发育状态的蛹的过冷却点和结冰点最低,分别为-11.15℃和-9.76℃;其次为滞育蛹,分别为-8.93℃和-7.63℃;而老熟幼虫最高,分别为-7.09℃和-3.43℃。此外,老熟幼虫的结冰点和过冷却点之间的差值最大为3.24℃,显著高于滞育蛹（1.30℃）和滞育解除蛹（1.39℃）。表明,倒春寒对已进入发育状态的柑桔大实蝇蛹不会造成不利影响。     

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.