单季晚稻褐飞虱发生程度综合客观预报模型

以上海地区单季晚稻褐飞虱Nilaparvatalugens(St l)发生程度为研究对象 ,用地面气象因子、5 0 0hPa高空环流因子和北太平洋海温场因子 ,在挑选了相关系数较高且稳定性又好的预报因子后 ,在逐步回归和逐步判别分析方法基础上 ,集成建立了单季晚稻褐飞虱发生程度的长、中、短期客观预报模式。长期、中期和短期预报模式的起报时间分别为当年的 1月、3月和 8月中旬。这 3种预报模式对 1 985～1 998年的历史拟合和 1 999～ 2 0 0 2年的预报误差均在 1级以内。     

2007－2012 年佛冈县稻飞虱灯下发生期及种群数量动态分析

明确佛冈县稻飞虱灯下发生期及灯诱种群数量动态,对当地稻飞虱的预测预报和防治工作具有重要意义.根据佛冈县2007-2012年白背飞虱和褐飞虱的灯诱数据,分析了该县白背飞虱和褐飞虱的灯下始见日、终见日、发生期及灯诱量等.结果表明在佛冈地区,白背飞虱和褐飞虱混合发生;白背飞虱的灯下始见日集中在3月底至4月上旬,明显比褐飞虱早一个月,终见日均在10月下旬,差别不大;稻飞虱在早稻和晚稻期间均会出现大小不一的灯诱高峰,早稻期间白背飞虱高峰期集中在5月中旬至6月中旬,褐飞虱灯诱高峰期较迟,主要在7月中旬前后;晚稻期间向背飞虱高峰期大多在9月上旬至10月上旬,褐飞虱高峰期在10月份;早稻期间,白背飞虱的灯诱量占绝对优势,晚稻期间褐飞虱的灯诱量上升,与白背飞虱灯诱量基本持平.因此,佛冈县稻飞虱的灯下发生期及种群数量动态在一定程度上可反映当地稻飞虱的发生情况.     

影响褐飞虱猖獗和为害的因素

本文是1977—1983年关于褐飞虱(Niloparvata Lugens St?l)迁飞和猖獗因素研究和观察的结果。褐飞虱在我省田间不能安全越冬,早稻上最初虫源系由冬季气温较高的南部地区依次长距离迁飞而来。连作晚稻一般受害不重,虫口高峰即为害盛期是在晚稻抽穗以后。造成在晚稻上猖獗的虫源固有本地的和陆续由南方迁入的,但主要系在晚稻移栽以后的8月中旬,由西南一季中稻区长距离迁入的。至于晚稻后期的受害程度,在这7年的虫口条件下,主要受后期尤其9月高温的影响。褐飞虱是一种比较典型的南方性害虫,即各虫态的发育历期随着温度升高而缩短,在25°—30℃适温条件下,20天左右即可完成一代,加之产卵量多,所以在晚稻上短时期内即能猖獗成灾。构成我省晚稻虫口基数的主要虫源,系夏季以后8月中旬迁入的虫口,决定晚稻受害程度的主要系9月份高温。但是造成褐飞虱猖獗的根本原因是感虫品种的推广和有利于虫口上升的耕作制度。     

褐飞虱(Nilaparvata lugens)发生的分形性质研究

运用分形理论以安徽省庐江县植保站和江苏省吴县值保站1979～1990年及太湖地区农科所1986～1998年间褐飞虱发生的田间系统调查资料为例,对褐飞虱发生的性质进行了探讨。结果表明：(1)庐江站、吴县站和太湖地区农科所褐飞虱发生在一定标度域内具有分形性质。其分维值分别为0．7158、0．52l2和0．2816;(2)褐飞虱发生的分维值是表征一定标度区间的发生程度差异的一个新的参数,分维值大,则发生程度轻,反之则重(3)分维数D值与褐飞虱发生的聚集程度是密切相关的,D值小聚集程度大,反之聚集程度小,D值可以作为褐E虱聚集分布程度的一个指标;(4)褐飞虱发生具有多重分形结构,其广义维数谱Dq曲线可以用于褐飞虱发生的预测预报。     

大气低温胁迫对中国褐飞虱年内初始迁入的影响

为了揭示大气低温胁迫对中国褐飞虱年内初始迁入的影响,更好地预警来自境外的褐飞虱早期迁入,通过统计2000-2017年中国华南、西南两个稻区褐飞虱年内的始见期和首次迁入峰日,逆推其迁飞轨迹和虫源区,分析大气温度场对迁飞过程产生的作用,比较了褐飞虱在我国不同稻区、不同年内初始迁入期受大气低温胁迫产生的作用差异。结果表明：（1）近年来褐飞虱初始迁入中国的时间提前,初始迁入华南稻区的时间比西南稻区早,华南稻区始见期提早可能与褐飞虱种群越冬北界北移有关。（2）西南稻区褐飞虱年内初始迁入的境外虫源主要来自缅甸,华南稻区年内初始迁入的境外虫源主要来自越南和老挝的中北部。（3）对盛行迁飞层的温场分布研究表明,在褐飞虱年内初始迁入过程中低温屏障发生的概率约为54.4%,迁入当晚降虫地的平均低温强度为13.45℃,平均降温幅度为1.88℃。其中低温胁迫在华南稻区表现更为显著（发生概率为58.3%,平均强度为13.18℃）,在始见期表现得更明显（发生概率为70.6%,平均强度为12.53℃）。     

我国褐飞虱迁入始见期的分析

常年3月下旬褐飞虱在我国的广西区西南南部、广东省西南部和云南省南部始见。随着时间的推移,始见湖北界不断向东向北呈扇形扩展;年间有—定的差异月时在110°E以西地域比以东地域北进速度要快一些。分析表明,4～6月在28°N、103°E附近的西南抵涡的形成和移动方位和始见期北界的移动关系密切。     

应用马尔可夫链理论对褐飞虱和白背飞虱发生程度的预测

褐飞虱Nilaparvata lugens (Stál)和白背飞虱Sogatella furcifera (Horváth) 是我国稻区的主要迁飞性害虫,给水稻生产带来严重危害.以重庆市秀山县1983～2007年田间褐飞虱和白背飞虱发生程度的时间序列资料,运用基于马尔可夫链理论的转移概率预测法,构建了1～5阶转移概率矩阵,根据每一阶概率矩阵单独进行回报的历史符合率计算各阶转移概率矩阵的权重,以预报年前5a褐飞虱和白背飞虱的连续发生状态预测第6年的发生级别.回报20a的结果历史符合率均达到90%,对2008年的预测也符合当年田间实际发生情况.该方法构建的5阶转移概率矩阵及其权重对于秀山县及其邻近地区褐飞虱和白背飞虱发生程度的长期预报具有重要指导意义,为害虫的长期可预测性提供了一种快速、有效的方法.     

近30年气候异常对江苏省褐飞虱灾变性迁入的影响

近30年来,中国褐飞虱的灾变性迁入因受气候变化的影响而出现了明显的时空变异,为了揭示气候异常对褐飞虱区域性灾变的影响,为我国褐飞虱灾变预警及其区域危害的防控提供理论依据,在收集1983—2008年江苏省32个植保站褐飞虱灯诱资料、1981—2008年太平洋海表温度和南方涛动指数数据及1983—2008年江苏省70个气象台站降水和气温观测资料的基础上,选取高邮、通州和宜兴作为江苏省不同水稻生长区的代表性测站(其中高邮代表江淮稻区,通州代表苏北沿海稻区,宜兴代表苏南稻区),通过对近30年来太平洋海温场、南方涛动、迁入区降水和温度异常与江苏省褐飞虱发生程度之间关系的分析,探讨了气候异常对该省褐飞虱灾变性迁入的影响。结果表明:(1)赤道东太平洋海表水温持续偏高的厄尔尼诺事件多引发江苏省褐飞虱偏重以上程度的发生,且其首次迁入峰的出现时间与厄尔尼诺事件开始期之间有1—14个月的滞后期。(2)南方涛动指数(SOI)持续出现负值的厄尔尼诺事件发生的当年或次年,褐飞虱为偏重以上的发生程度,且其首次迁入峰的出现时间滞后于SOI负值开始期1—14个月。(3)登陆并影响江苏的强热带气旋偏多的拉尼娜年也会出现褐飞虱偏重以上的发生。(4)降水对褐飞虱迁入的影响明显,但有限制条件;降水量大、降水日数多的年份褐飞虱迁入量大、发生程度重;以6—10月降水量、降水日数和降水强度为预报因子,建立了褐飞虱发生等级的回归方程,方程拟合和试报效果好。(5)夏秋季6—10月地面气温的异常对江苏省褐飞虱迁入的发生有一定的影响,秋温偏高的年份常导致江苏省褐飞虱偏重以上的发生。     

七(6)代褐飞虱大发生原因及防治对策

褐飞虱Nilaparvatalugens（Stal）是浙南地区连作晚稻后期的主要害虫，在大发生年份，如1995、1996年，七（6）代褐飞虱连续在我市连作晚稻部分田块上大发生，有些田块甚至达到特大发生的程度。在一些地区，由于防治失时及农药选择不当等原因，导致水稻毁秆倒伏，造成严重损失。为此，本文就1995与1996年两年的田间调查结果，分析其原因，对防治对策进行讨论。1大发生的原因1．1有利的气象因子有利的气象因子是诱发七（6）代褐飞虱大发生的一个重要原因。1995年9月下旬旬平均气温23．2℃，比1994年同期的22．3℃高出0．9℃；降雨量73．6mm…     

褐飞虱（Nilaparvata lugens (Stal)）前期迁入与ENSO指标的遥相关及其中长期预测

分析了全国6个不同褐飞虱发生区内16个监测点的褐飞虱（Nilaparvata lugens（St（a）l））前期迁入量与从前两年1月至当年6月各月ENSO 指标（包括4个Nino区海温和南方涛动指数（SOI）的月平均距平值）遥相关的时空分布.结果表明,与褐飞虱前期迁入量显著遥相关的ENSO指标主要为N3区、N4区和N3.4区的海温,三者共占显著相关指标总数的71.8%.在时间分布上,显著遥相关的ENSO指标主要分布在前两年和前一年（约占84%）,当年仅占16.7%.从相关性质来看,褐飞虱前期迁入量与各Nino区海温在前两年至前一年春季之前呈负相关,而与前一年冬季至当年春季呈正相关;与前一年夏秋季ENSO指标的相关性质则无明显规律.褐飞虱前期迁入量与各Nino区海温和与SOI遥相关的相关性质相反.以前期显著相关的ENSO指标为预测因子,用逐步回归法建立褐飞虱前期迁入量的中长期预测方程.筛选出历史回检率和预测准确性较高的方程,经集成后共获得12个预报模型,可提前3～27个月作出预测,预测的准确率为88.9%.     

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.