荔蝽卵平腹小蜂越冬环境初步调查

荔蝽卵平腹小蜂Anastatussp．是一种卵寄生蜂,主要寄生于荔枝蝽TessaratomapapillosaDrary的卵内,对荔枝蝽的为害有一定的控制作用。60年代初,蒲蛰龙等[1]对该蜂生物学特性开展了研究,并成功地利用蓖麻蚕卵、柞蚕卵作为替代寄主大量繁殖此蜂,释放于荔枝园防治荔枝蝽,取得了良好效果。从80年代开始,刘志诚等[2]开展人工卵的研究,取得成功,目前已经形成一套成熟的人工繁蜂、放蜂防治荔枝蝽的技术。但在自然界,该蜂难以形成强大的自然种群,越冬后早春的自然种群数量相当低,早春寄生率不高。在释放平腹小蜂的同时,如何保护它们,…     

平腹小蜂防治荔枝蝽象试验研究

20 0 0年 2～ 8月 ,在广西北流潮塘、荔宝、花果山等果场进行了平腹小蜂防治荔枝蝽象试验 ,总面积约2 0 hm2 ,8～ 1 0年生龙眼、荔枝树约 4 0 0 0株。根据当地荔枝蝽象的生活习性及发生规律 ,共放蜂 2次 ,结果为 :在放蜂区和对照区内 ,荔枝蝽象卵寄生天敌平腹小蜂、跳小蜂的总寄生率分别为 94 .3%和 1 8.9% ,相比效果明显 ,同时 ,果园中若虫数量显著降低 ,控制在经济危害阈值之下。     

斑痣悬茧蜂的飞行能力和野外扩散行为

为探究斑痣悬茧蜂在野外的寄主搜寻行为,首先利用飞行磨测定了最大理论飞行能力,然后在大豆田进行了两次放蜂试验,通过回收或采集斜纹夜蛾寄主幼虫统计寄生情况,分析了寄生蜂的有效搜寻及其影响因素.飞行磨吊飞测定结果表明,个体起飞次数为14.48次±0.82次,总飞行距离1283.00 m±45.60m,总飞行时间2374.79 s±89.91 s,平均飞行速度0.54 m·s-1±0.004 m·s-1,最长的单次飞行时间475.21 s±76.97 s.田间放蜂试验结果表明,在风速≤4.2 m·s-1的大豆田中,方位对寄生率没有显著影响;但寄生率随时间延长和离放蜂点的距离增加而显著降低.放蜂的次日寄生蜂可扩散到36 m处.最后,对斑痣悬茧蜂野外搜寻行为特征进行了讨论.     

荔枝蝽田间种群消长动态及空间分布型研究

对海南省儋州地区荔枝园中荔枝蝽Tessaratoma papillosa(Drury)种群动态及空间分布进行了系统调查与分析。结果表明,在2005—2006与2008—2009年期间,荔枝蝽的产卵高峰期分别为4月与2月,若虫高峰期为3月,成虫高峰期分别为4月及7月;分析表明荔枝蝽各虫态在荔枝园中均为聚集分布,且成虫个体间相互排斥。     

封面照片

正照片示在荔枝Litchi chinensis花穗静息的荔枝蝽Tessaratoma papillosa(半翅目:蝽科)成虫。该虫是传播龙眼鬼帚病病原体的传病介体昆虫,以若虫及成虫为害荔枝龙眼果树,在中国南方及东南亚地区危害严重。本期报道了荔枝蝽生物学,触角和臭腺,预测预报及防治研究进展综述(pp. 645-654)。照片由全林发于2021年3月摄于广东省广州市白云区钟落谭荔枝龙眼实验基地。     

荔枝蝽生物学及防治技术的研究进展(英文)

荔枝蝽Tessaratoma papillosa是荔枝和龙眼生产中的重要害虫,在中国南方及东南亚地区危害严重。该虫以若虫及成虫吸食寄主植物的嫩芽、嫩梢、花穗和幼果,成虫和3龄以上若虫是传播龙眼鬼帚病病原体的传病介体昆虫。本文综述了近60年来国内荔枝蝽的研究情况,旨在为广大科研工作者提供更详尽的荔枝蝽研究现状,以期为该虫的深入研究及绿色防控技术的研发提供参考。荔枝蝽为不完全变态昆虫,一年发生1代,若虫期80 d左右,成虫寿命为203~371 d,单雌产卵总量190粒左右,在习性上表现出明显的聚集性、趋光性、趋色性和趋嫩梢性。近年来,通过荔枝蝽触角感受器分类及分布观察,触角转录组数据测定和分析,臭腺解剖观察以及臭腺分泌物组分分析,对该虫触角和臭腺两大器官组织已有较深入研究及了解。目前,荔枝蝽的发生期主要通过卵巢发育分级法进行预测预报,对该虫的防治仍然是以化学防治为主,农业防治、物理防治和生物防治为辅的策略。其中,荔枝蝽生物防控技术研究报道最多,主要集中在天敌的保护利用和生物源农药的应用。由于荔枝蝽虫源的季节性制约和发生为害地域限制,对该虫的研究进展缓慢,深层次的研究较少,且所涉及到的研究领域也比较窄。从组学、分子生物学、细胞生物学等多角度探明荔枝蝽对寄主植物的选择机制,与寄主植物、天敌及共生菌间的互作关系,以及抗药性机理等,将为荔枝蝽绿色防治技术带来新思路。     

敌百虫对荔枝蝽几种代谢酶活性的影响

采用微量点滴法测定了荔枝蝽对敌百虫的敏感性,并对不同浓度敌百虫处理后荔枝蝽体内羧酸酯酶、酸性磷酸酯酶和碱性磷酸酯酶的活性进行了比较。结果表明,敌百虫对荔枝蝽的LC50为28.840 mg.mL-1;随着敌百虫处理浓度的升高,荔枝蝽体内羧酸酯酶活性显著升高,不同处理剂量间存在显著差异,酸性磷酸酯酶和碱性磷酸酯酶活性各药剂处理剂量间没有差异。表明羧酸酯酶活性的升高可能会导致荔枝蝽对敌百虫的敏感性下降。     

荔枝蝽成虫对其臭腺分泌物组分的触角电生理和行为反应

培养皿生物测定结果表明,荔枝蝽Tessaratoma papillosa(Drury)臭腺分泌物的乙醚提取物对成虫有显著的驱避作用.气质联用仪(GC-MS)分析结果表明,荔枝蝽雌雄成虫臭腺乙醚提取物中具有5种挥发性物质,即(E)-2-辛烯醛、十一烷、十二烷、十三烷及一个未知组分.荔枝蝽对(E)-2-辛烯醛、十一烷、十二烷与十三烷这4种组分的触角电生理(EAG)反应结果表明,这些化合物均能引起荔枝蝽成虫的EAG反应,其中(E)-2-辛烯醛引起雌雄成虫触角的反应最强,分别为0.50 mV与0.4 mV;"Y"型嗅觉仪生测结果表明,(E)-2-辛烯醛对荔枝蝽成虫能产生极显著的驱避作用(P <0.01).可见,荔枝蝽成虫臭腺分泌物对荔枝蝽具有显著的生物活性,可望通过进一步研究应用于荔枝蝽的防控体系.     

六种荔枝果蛀虫的研究

荔枝害虫种类甚多,就笔者两年来的观察已知有50余种。在过去一般果农及若干研究荔枝害虫的学者,均认为荔枝蝽Tessaratoma papillosa(Drury)(蝽科Pen-tatomidae)为荔枝果实的唯—首要害虫,但若就其为害严重性而言,本文所述6种果     

茶翅蝽沟卵蜂和黄足沟卵蜂对茶翅蝽的寄生潜能研究

茶翅蝽Halyomorpha halys(Stl)是水果和蔬菜生产中的重要害虫。为了寻找优势卵寄生蜂用于其生物防治,本文进行了相关的野外调查和室内试验。通过定期野外采集茶翅蝽卵块,培育、收集和鉴定寄生蜂,发现在自然环境中茶翅蝽卵粒的寄生率为56.29%,其中茶翅蝽沟卵蜂比例最高,占77.66%;其次是黄足沟卵蜂占20.44%。Y型嗅觉仪测定结果显示,茶翅蝽沟卵蜂和黄足沟卵蜂对茶翅蝽卵均具有明显的选择趋性。室内寄生能力试验结果表明,茶翅蝽沟卵蜂与黄足沟卵蜂单独作用的寄生率分别为94.06%和84.21%,与两种寄生蜂混合寄生茶翅蝽卵的寄生率91.65%均无显著性差异。两种寄生蜂混合寄生时,茶翅蝽沟卵蜂与黄足沟卵蜂的寄生比例分别为58.95%和41.05%,二者之间无显著差异。     

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