5种杀虫剂对滇东白背飞虱种群的毒性及其田间药效

【目的】为持续有效防控白背飞虱,研究云南东部白背飞虱种群对常用5种杀虫剂的敏感性及药剂的田间防治效果。【方法】采用室内稻茎浸渍法测定白背飞虱种群对5种杀虫剂的敏感性,同期通过田间小区试验评价5种杀虫剂对白背飞虱种群的防治效果。【结果】与敏感种群比较,噻虫嗪、噻嗪酮、吡虫啉、吡蚜酮和毒死蜱对滇东白背飞虱种群的LC_(50)分别为0.208、0.459、0.608、3.108、1.256 mg·L~(-1),抗性倍数分别为2.2、10.4、5.6、6.5、5.3倍;白背飞虱对噻虫嗪无抗性,对吡虫啉、吡蚜酮和毒死蜱为低水平抗性,对噻嗪酮为中等水平抗性;5种杀虫剂药后1、5和10 d对白背飞虱种群的田间防控效果均有显著差异。除了吡蚜酮外,其他药剂的防效均在80%以上,其中以吡虫啉和噻嗪酮的持续期较长,药后10 d仍在90%以上;噻虫嗪和吡虫啉药后1和5 d的防效达90%以上;吡蚜酮药效在供试药剂中防效最低,在64.88%～77.82%之间。【结论】滇东师宗白背飞虱种群对噻嗪酮为中等水平抗性,对吡虫啉、吡蚜酮和毒死蜱均为低水平抗性,对噻虫嗪无抗性,田间防控效果以吡虫啉和噻嗪酮为最好。建议滇东稻区可以使用吡虫啉和噻嗪酮药剂防控白背飞虱,注意控制吡蚜酮的使用次数与用量。     

褐飞虱和白背飞虱对几类杀虫剂的敏感性

为了科学用药和抗性治理提供理论基础, 采用稻茎浸渍法测定了2008年7月采自浙江省杭州市和宁波市褐飞虱 Nilaparvata lugens (Stål)种群对7种杀虫剂的抗药性及褐飞虱和白背飞虱Sogatella furcifera (Horváth)种群对16种杀虫剂的敏感性。褐飞虱抗药性测定结果表明, 与相对敏感品系相比, 杭州种群和宁波种群对吡虫啉的抗性倍数分别为479.0倍和366.1倍; 对氯噻啉的抗性倍数分别为81.1倍和50.9倍; 对噻虫嗪的抗性倍数分别为10.3倍和9.4倍; 对噻嗪酮和氟虫腈分别产生了5.0~8.6倍和15.8~17.0倍的抗药性; 对烯啶虫胺和啶虫脒的抗性倍数在3倍以下。两种稻飞虱对杀虫剂的敏感性测定结果表明: 噻虫嗪、噻嗪酮、烯啶虫胺和毒死蜱对褐飞虱和白背飞虱种群都具有较高的室内毒力。当田间褐飞虱和白背飞虱混合发生时, 可选用噻虫嗪、噻嗪酮、烯啶虫胺和毒死蜱进行防治, 不宜使用吡虫啉、氯噻啉和氟虫腈防治。     

吡蚜酮对白背飞虱的发育、繁殖和药剂敏感性的亚致死效应（英文）

【目的】白背飞虱Sogatella furcifera(Horváth)是我国重要的水稻害虫。本研究旨在确定亚致死浓度吡蚜酮对白背飞虱发育和繁殖及亚致死浓度处理后白背飞虱对其他药剂的敏感性变化的影响。【方法】用生命表法研究了亚致死浓度吡蚜酮处理对白背飞虱F0及F1代发育历期、存活率、羽化率和寿命的亚致死效应;采用稻茎浸渍法,测定了亚致死浓度吡蚜酮处理后白背飞虱对其他药剂的敏感性。【结果】经LC_(10)和LC_(25)吡蚜酮处理后,白背飞虱F0代3-5龄若虫历期比对照(8.25 d)分别延长了1.98 d和4.25 d,寿命分别比对照(14.54 d)缩短了0.49和1.73 d,3-5龄若虫存活率(分别为85.00%和68.50%)和羽化率(分别为75.89%和67.78%)比对照(分别为92.00%和85.90%)下降,其中LC_(25)处理组与对照比差异显著。LC_(10)和LC_(25)吡蚜酮处理的白背飞虱F1代羽化率(分别为76.97%和68.94%)、交尾率(分别为77.79%和66.44%)和卵孵化率(分别为73.19%和68.67%)比对照(分别为88.22%,86.67%和87.26%)显著降低,但只有LC_(25)处理组的F1代发育历期与对照组有显著差异;LC_(10)和LC_(25)吡蚜酮处理后的F1代单雌产卵量比对照(147.80粒/雌)显著下降(分别为112.36和88.34粒/雌),种群相对适合度比对照(1.00)也明显下降(分别为0.41和0.20)。经吡蚜酮LC_(10)和LC_(25)处理后,测定白背飞虱对噻虫嗪,毒死蜱和噻嗪酮的敏感性结果显示,这3种杀虫剂的LC50在LC_(10)处理组中分别为2.16,40.87和3.12 mg/L,在LC_(25)处理组中分别为4.93,17.96和8.39 mg/L。噻虫嗪、毒死蜱、噻嗪酮的相对毒力指数(RTI)结果显示,LC_(10)和LC_(25)处理后的白背飞虱对这3种杀虫剂的敏感性均降低。【结论】吡蚜酮处理后,白背飞虱对其他药剂的敏感性均降低。吡蚜酮亚致死浓度处理能降低白背飞虱的繁殖力,抑制种群增长,亚致死浓度处理后的白背飞虱种群对噻虫嗪、毒死蜱和噻嗪酮的敏感性均降低。     

氯虫苯甲酰胺对白背飞虱实验种群的亚致死效应

为正确评估防治水稻鳞翅目害虫的新型杀虫剂氯虫苯甲酰胺对非靶标害虫白背飞虱Sogatella furcifera (Horváth)的影响, 本文采取稻茎浸渍法测定了氯虫苯甲酰胺对白背飞虱的毒力, 利用生命表技术研究了氯虫苯甲酰胺对白背飞虱的亚致死效应。结果表明： 氯虫苯甲酰胺对白背飞虱3龄若虫和成虫的LC₅₀分别为19.26 mg/L和19.69 mg/L。以氯虫苯甲酰胺LC₁₀和LC₂₅剂量分别处理白背飞虱3龄若虫后, F₀和F₁代雌虫产卵量及其寿命均降低, 尤其LC₂₅处理与对照间存在显著差异（P<0.05）, F₀和F₁代雌虫寿命分别缩短了1.80 d和2.62 d, F₀和F₁代雌虫产卵量分别减少了52.94粒和78.45粒。药剂处理对F1代各虫态发育历期也有一定影响。根据不同剂量处理后白背飞虱各发育阶段的存活率和成虫的繁殖力, 组建了生殖力生命表, 发现LC₁₀和LC₂₅剂量处理的种群内禀增长率rm分别降低了11.25%和34.41%, 净增殖率R0分别降低了36.56%和74.57%, 而世代平均历期T和种群加倍时间t均延长。结果说明, 氯虫苯甲酰胺LC₁₀和LC₂₅剂量可抑制白背飞虱种群的增长; 大田中使用氯虫苯甲酰胺防治鳞翅目害虫时, 可抑制同时发生的非靶标害虫白背飞虱田间种群增长。     

RNAi和取食不同品种水稻后白背飞虱多铜氧化酶4基因的表达差异及生物学效应

【目的】分析RNAi及取食不同品种水稻后白背飞虱Sogatella furcifera多铜氧化酶4(multicopper oxidase 4, MCO4)基因的表达差异和生物学效应,以期为该基因的功能研究提供理论依据。【方法】通过生物信息学技术方法分析白背飞虱MCO4基因的核苷酸和氨基酸序列;利用RNAi技术沉默白背飞虱3龄若虫的MCO4基因,检测显微注射法和饲喂法的沉默效率,研究该基因被干扰后对白背飞虱3龄若虫存活率的影响;白背飞虱成虫取食不同抗性水稻品种24 h后,采用RT-qPCR检测其体内MCO4基因表达量的变化,并统计其体重。【结果】白背飞虱MCO4基因的核苷酸序列全长为2 166 bp,编码721个氨基酸。显微注射法进行MCO4基因的RNAi可成功沉默白背飞虱的MCO4基因,且沉默效率远高于饲喂法。MCO4基因被RNAi沉默后白背飞虱3龄若虫存活率显著低于正常若虫的。与取食水稻感虫品种TN1相比,取食水稻抗虫品种IR26的成虫MCO4基因表达量显著增加,且成虫体重显著降低。【结论】显微注射法可以更好地干扰白背飞虱MC04基因的表达。沉默MCO4基因对白背飞虱3龄若虫的存活率有显著影响,我们推测MCO4基因在白背飞虱取食水稻中具有重要的作用。     

湖北稻区白背飞虱田间种群抗药性监测

【目的】白背飞虱Sogatella furcifera是水稻上的主要害虫之一,目前白背飞虱主要以化学防治为主,为指导田间合理用药,本文报道了湖北白背飞虱田间种群对防治药剂的抗性变化情况。【方法】采用稻茎浸渍法监测了2011-2014年采自湖北鄂州蒲团、鄂州长港、枝江问安和石首南口稻田的白背飞虱4个田间种群对11种杀虫剂的抗性。【结果】白背飞虱田间种群已对噻嗪酮产生中等水平抗性(抗性倍数RR=13.0~38.6倍);对吡虫啉处于敏感至中等的抗性水平(RR=2.6~15.4倍);对噻虫嗪(RR=2.1~6.9倍)、噻虫胺(RR=3.0~7.0倍)、呋虫胺(RR=2.5~7.0倍)及啶虫脒(RR=3.3~8.2倍)处于敏感至低抗水平;所有白背飞虱田间种群均对烯啶虫胺(RR=2.2~4.9倍)、异丙威(RR=2.0~4.6倍)及醚菊酯(RR=1.8~4.0倍)敏感;除长港(2011-2012年)与蒲团(2012年)白背飞虱田间种群对吡蚜酮敏感外,其余白背飞虱田间种群均对吡蚜酮产生中等水平抗性(RR=15.2~91.0倍);白背飞虱长港田间种群(2013年与2014年种群)对毒死蜱产生中等水平抗性,抗性倍数分别为15.6和10.1,其余白背飞虱田间种群则对毒死蜱为敏感或低水平抗性(RR=1.7~8.5倍)。【结论】根据监测结果,建议加强对噻嗪酮、吡虫啉和吡蚜酮抗性监测,同时减少噻嗪酮、吡虫啉和吡蚜酮在水稻田使用次数,降低杀虫剂对白背飞虱田间种群选择压,延长其在田间的使用寿命。     

广东白背飞虱种群对常用杀虫剂的敏感性测定

在室内采用稻茎浸渍法测定了广东省广州市和南雄市2个白背飞虱种群对吡虫啉、呋虫胺、烯啶虫胺、噻虫嗪、噻嗪酮、吡蚜酮等6种常用农药的敏感性。结果表明:不同白背飞虱种群对吡虫啉的敏感性最高,LC50值在0.0133-0.1538 mg/L之间;对噻嗪酮敏感性最低,LC50值在0.8806-1.6948 mg/L之间。不同白背飞虱种群对同一种杀虫剂的敏感性差异较大。     

湖北稻区褐飞虱田间种群对常用杀虫剂抗药性监测

【目的】明确目前褐飞虱Nilaparvata lugens田间种群对常用防治药剂的抗性现状,为制定褐飞虱的科学用药策略提供科学依据。【方法】于2009-2014年采用稻茎浸渍法监测了湖北褐飞虱武穴梅川、枣阳十里铺、孝感陈店、鄂州长港和武汉江夏稻田的褐飞虱田间种群对11种杀虫剂的敏感性。【结果】湖北稻区褐飞虱田间种群已对吡虫啉(抗性倍数RR=101.8~1 239.4)、噻嗪酮(RR=15.9~1 326.3)产生高水平抗性;对噻虫嗪(RR=24.9~146.5)产生中等水平至高水平抗性;对噻虫胺(RR=9.9~16.5)、呋虫胺(RR=13.5~15.9)、乙虫腈(RR=18.3~60.4)、毒死蜱(RR=17.4~29.8)、异丙威(RR=13.9~46.0)产生中等水平抗性;对啶虫脒(RR=5.1~9.9)产生低水平抗性;对噻虫啉(RR=3.9~7.1)处于敏感至低水平抗性水平;对醚菊酯(RR=1.3~4.9)处于敏感水平。此外,褐飞虱对噻虫嗪、噻嗪酮抗性上升明显,同时褐飞虱对吡虫啉抗性也有上升的趋势。【结论】仍需暂停吡虫啉、噻嗪酮在水稻上防治稻飞虱,严格限制吡蚜酮在水稻上的使用次数;醚菊酯可作为吡虫啉、噻嗪酮和吡蚜酮的替代药剂或轮换药剂。     

灰飞虱对噻嗪酮的抗性风险及机理

为研究灰飞虱对噻嗪酮的抗性发展规律及抗性生化机理,采用稻苗喷雾法对灰飞虱种群进行连续筛选获得高抗性品系,估算其现实遗传力并进行田间抗性风险预测;采用稻苗浸渍法测定杀虫剂对灰飞虱的毒力及交互抗性;利用生物化学方法测定不同品系之间的解毒酶活力,探讨灰飞虱对噻嗪酮的抗性生化机理.结果表明:用噻嗪酮对灰飞虱种群连续筛选32代,其抗性倍数达到168.49倍,现实遗传力h~2为0.11.当杀死率为80%~90%时,预计灰飞虱对噻嗪酮的抗性增长10倍,仅需要5~6代.田间实际的现实遗传力要比室内选择种群估计低一些,预计田间抗性提高10倍所需要时间会更长.交互抗性测定结果表明,灰飞虱抗噻嗪酮品系与吡虫啉和噻虫嗪之间有高水平交互抗性,与啶虫脒有低水平交互抗性,与吡蚜酮和毒死蜱无交互抗性.增效作用和解毒酶活力测定结果显示,抗性品系细胞色素P450单加氧酶活力提高最大,酯酶次之,谷胱甘肽-S-转移酶无显著变化.田间使用噻嗪酮防治灰飞虱存在较大抗性风险,可与吡蚜酮和毒死蜱等交替使用以延缓抗性发展;3种解毒酶中,细胞色素P450单加氧酶在灰飞虱对噻嗪酮的抗性发展中起到了重要作用.     

白背飞虱种群数量变动的自然因素初步探讨

<正> 白背飞虱Sogatella furcifera(Horváth)是水稻重要害虫之一。其年度间种群数量变动幅度较大,究其原因,除了本地虫口基数、迁入虫量和食料因素外,气候和天敌是影响白背飞虱种群盛衰的重要因素。我们于1970—72年在崇安县和1979—82年在沙县和福州对白背飞虱的种群动态及其与气候因素和天敌因素的关系,进行了初步的调查研究,现将结果报道如下。     

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.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

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.