机敏异漏斗蛛的捕食行为及其控虫效能评估

为掌握园林常见蜘蛛对害虫的控制能力,在实验室条件下研究了不同发育期机敏异漏斗蛛Allagelena difficilis(Fox)对黑腹果蝇Drosophila melanogaster的捕食行为及其功能反应,并对雌、雄蛛捕食能力进行了比较。结果表明,机敏异漏斗蛛幼蛛和成蛛的捕食行为谱相似,均可分为靠近、奔向和试探、捕获、吸食、残体处理、清理附肢和休整,但具体行为稍有差异;对机敏异漏斗蛛雌性成蛛捕食黑腹果蝇的功能反应拟合,其结果符合HollingⅡ型方程:Na=1.003N/(1+0.002N),r2=0.98,其瞬间攻击率为0.95。雌蛛在未孕卵时其捕食量与雄性成蛛相近,但孕卵雌成蛛捕食量明显高于雄蛛。此结果可以为机敏异漏斗蛛的研究和利用提供依据。     

横纹金蛛生物学特性初步研究

横纹金蛛在山东省日照市一年1代,以1龄幼蛛在卵袋内越冬。5月上旬开始出蜇;幼蛛6龄,老熟幼蛛7月中旬羽化。8月上旬产卵,8月下旬孵化。卵期21～45d,幼蛛生活历期311.2d,成蛛寿命52～87d,雌雄比4:1;成蛛日食量0.50609g,日网捕虫30头,每只成蛛期共食虫35.4263g,网捕虫2405头,是一些害虫的重要天敌。该蛛发生与气候、海拔、天敌等关系密切。     

皱胸尖裂姬蜂对机敏异漏斗蛛的拟寄生行为及其发育特征

寄生蜂是蜘蛛的主要天敌类群之一,但寄生于漏斗蛛的寄生蜂种类较少,且缺乏相关寄生蜂的详细研究报道。我们研究了皱胸尖裂姬蜂(Oxyrrhexis rugosus)对机敏异漏斗蛛(Allagelena difficilis)的拟寄生,旨在揭示蜘蛛寄生蜂的拟寄生行为及其发育特征。显微镜下观察了12头机敏异漏斗蛛头胸部背面的皱胸尖裂姬蜂卵,并以均值法统计了皱胸尖裂姬蜂各发育阶段的历期,进一步观察了皱胸尖裂姬蜂寄生机敏异漏斗蛛后对寄主的影响。交配后的雌性皱胸尖裂姬蜂经过寻找、降落、蛰刺蛛体后伺机将卵产在机敏异漏斗蛛的头胸部背面后部;孵化后的皱胸尖裂姬蜂幼虫头部形成一个特殊摄食导管,通过摄食导管获取蛛体的营养;幼虫随着龄期增长,体色由浅变深,历期约10 d;幼虫老熟后在蛛网的漏斗状管道内结茧化蛹,蛹期约为12 d;成体雌、雄蜂寿命约为11 d,皱胸尖裂姬蜂的平均生活史周期约为33 d。皱胸尖裂姬蜂寄生后对寄主蜘蛛的行为和生活状态造成了严重的影响,随着幼虫龄期增长被寄生机敏异漏斗蛛不再进食、蜕皮,活动减少,蛛体逐渐萎缩,直至老熟幼虫离开蛛体时,蜘蛛死亡。该研究不仅增加了漏斗蛛寄生性天敌的已知种类,而且初步了解了以漏斗蛛为寄主的姬蜂的产卵行为、后代的发育特征以及对寄主蜘蛛的影响,这将为研究蜘蛛寄生蜂及其与寄主蜘蛛之间的化学通讯和协同进化提供重要的基础资料。     

机敏异漏斗蛛不同感觉对捕食和趋向行为的影响

【目的】蜘蛛的感觉在发现猎物和捕食过程中起重要作用,研究机敏异漏斗蛛Allagelena difficilis(Fox)的不同感觉对其捕食和趋向行为的影响,有助于揭示影响漏斗蛛捕猎的主要感觉因素及其机制。【方法】视觉屏蔽法、"Y"型嗅觉仪法、去除蛛网法等方法。【结果】视觉和嗅觉对机敏异漏斗蛛的捕食量和趋向行为无显著影响,但蛛网的存在对其捕食量影响明显:视觉屏蔽与未屏蔽的机敏异漏斗蛛24 h捕食黑腹果蝇Drosophila melanogaster Meigen量分别为25.20头/管和26.00头/管,两者之间差异不显著;嗅觉测试发现,在不同的气流条件下,机敏异漏斗蛛停留、选择有猎物管臂和对照管臂的数量之间差异均不显著;另外,该蛛在无蛛网情况下也可捕食,但捕食量极低,与已结网蛛之间的捕食量差异极显著(P<0.01),随着蛛网的修复,两者之间捕食量差距逐渐减小,至24 h时,两者捕食量相近。【结论】机敏异漏斗蛛主要通过机械感觉线索感受蛛网振动、听觉以及猎物的直接碰触发现和捕获猎物,视觉和嗅觉对其捕食行为影响不明显。     

低温对小菜蛾实验种群的影响

研究了低温(<8℃)对小菜蛾的发育、存活和繁殖的影响.结果表明,卵和蛹在4℃和6℃下死亡率随处理时间的延长而增加,在分别处理55d和70d后,卵和蛹全部死亡;经4℃和6℃处理的蛹,在16℃下羽化成虫的平均产卵量随处理时间的延长而减少,处理45d时,产卵量均为0.小菜蛾幼期各虫态在0℃以下,死亡率随低温强度加大和处理时间的延长而增高.就耐寒力而言,3龄幼虫和蛹最强,其次是2龄和4龄幼虫,卵和1龄幼虫的耐寒力最弱.不同低温和时间处理小菜蛾幼期虫态对其后继虫态的发育历期有较大影响,总体说来,经过处理的小菜蛾幼期虫态,其后继虫态的发育历期普遍延长,一般处理某一虫态对其相邻虫态发育历期的影响最大.小菜蛾蛹经低温处理后其羽化成虫的产卵量随着蛹期所经历低温强度的增强和时间延长而减少.     

低温对小菜蛾实验种群的影响

研究了低温(<8℃)对小菜蛾的发育、存活和繁殖的影响结果表明,卵和蛹在4℃和6℃下死亡率随处理时间的延长而增加,在分别处理55d和70d后,卵和蛹全部死亡;经4℃和6℃处理的蛹,在16℃下羽化成虫的平均产卵量随处理时间的延长而减少,处理45d时,产卵量均为0小菜蛾幼期各虫态在0℃以下,死亡率随低温强度加大和处理时问的延长而增高就耐寒力而言,3龄幼虫和蛹最强,其次是2龄和4龄幼虫,卵和1龄幼虫的耐寒力最弱不同低温和时间处理小菜蛾幼期虫态对其后继虫态的发育历期有较大影响,总体说来,经过处理的小菜蛾幼期虫态,其后继虫态的发育历期普遍延长,一般处理某一虫态对其相邻虫态发育历期的影响最大小菜蛾蛹经低温处理后其羽化成虫的产卵量随着蛹期所经历低温强度的增强和时间延长而减少。     

驼背额角蛛和隆背微蛛各龄期比较

图1一龄幼蛛(1.驼背额角蛛2.隆背微蛛)图2二龄幼蛛(1.驼背额角蛛2.隆背微蛛)驼背额角蛛(Gnathonarium gibberum)和隆背微蛛(Erigone prominens)是农田害虫的重要天敌。由于发生量大,分布较广,对控制飞虱、叶蝉等水稻害虫有一定作用。在野外采集以及农田统计害虫天敌蜘蛛的种类和数量时,往往对幼蛛的鉴定和计数有一定困难,而国内外关于蜘蛛各龄期特征的描述和研究报道较少。为此,对该二种蜘蛛作了饲养观察,并对其幼蛛各龄期特征描述如下。方法从田间采回成蛛,待产卵、孵化后从卵袋中剥出一龄幼蛛及经蜕一次皮后爬出卵袋的二龄幼蛛。以后各龄…     

拟水狼蛛的生物学生态学特性

运用田间观察与室内外饲养相结合的方法,对稻田蛛蛛优势种拟水狼蛛Pirata subpiraticus的生物学生态学特性进行了研究。拟水狼蛛在重庆地区1a发生3－4代,第4代不完整,以第2代历期最短,第3代（越冬代）历期最长;以成蛛或幼蛛越冬;5月初即由田埂向稻田内迁移,在水稻生育期间出现3次卵高峰、2次种群密度高峰;在田间具掘土作穴习性,室内发现4龄后的幼蛛在袋状网内蜕皮、交配期和携卵期有结袋状网或幕状网的习性;属游猎型蜘蛛,可步行、跳跃在植株、水面、陆地等处捕食飞虱、叶蝉、粘虫、螟虫等多种稻虫,捕食量与龄期、蜕皮和性别有关;受惊时,能入水中潜行和潜伏。雌雄蛛均可多次交配,雌蛛一生可产卵3－6次,卵囊含卵量25－130粒,平均75粒。平均孵化率90．5％。孵化的幼蛛,先群集在雌蛛的背部,3－5d后离开雌蛛分散捕食。幼蛛一般蜕皮7－8次,出卵囊前已蜕皮至少1次。拟水狼蛛的产卵前期2－6d,平均3d;卵期9－15d,平均11.4d;幼蛛期57－133d,平均81.6d;成蛛期128－186d,平均140d左右,雌蛛较雄蛛长24－51d,平均39.6d。性比除第1代外的各代均为雌多于雄蛛。论文详细记载了拟水狼蛛求偶与交配行为过程、产卵与护卵习性、孵化及携幼行为、幼蛛生长、蜕皮、各龄期形态特征、亚成蛛及性成熟。幼蛛出卵囊后至性成熟的成活率为21．4％－56．3％,平均达35．0％。室内饲养发现在一定湿度条件下,不提供食物成蛛可存活28－57d,平均42．7d。     

星豹蛛求偶和交配行为

以星豹蛛(Pardosa astrigera)为研究对象,在室内对其求偶和交配行为进行了描述。雄蛛"俯卧撑"式动作(push-up)在求偶中具重要作用。交配初期,两侧触肢交替插入;随交配进行,单侧触肢连续插入3~5次后才换另一侧触肢插入,触肢每插入一次,基血囊膨大多次。完整交配一次雄蛛触肢器平均插入次数为29·625。交配前求偶时间、交配持续时间和有效交配时间分别平均为6min、32min25s和11min11s。星豹蛛雄蛛可进行多次交配,而雌蛛一般为单次交配。雌蛛交配状态(是否已经交配)影响其同类相食行为,已交配雌蛛对雄蛛同类相食率显著高于未交配雌蛛对雄蛛同类相食率。     

法希里舞蛛生物学特性的观察

法希里舞蛛在鲁东南沿海地区一年发生1代,以幼蛛或亚成蛛在洞穴内、杂草丛基部越冬。翌年2月中旬出蜇,幼蛛经8龄后于3月上旬成熟。3月下旬开始卵,卵期38.2d,幼蛛期291d,成蛛期123d,雌雄比为5:3。成蛛日食量0.4386g,是多种害虫的重要天敌。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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.     

Synthesis and antimicrobial studies of hydrazone derivatives of 4-[3-(2,4-difluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic acid and 4-[3-(3,4-difluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic acid

Microbial resistance to antibiotics is an unresolved global concern, which needs urgent and coordinated action. One of the guidelines of the Centers for Disease Control and Preventions (CDC) to combat antibiotic resistance is the development of new antibiotics to treat drug-resistant bacteria. In our effort to find new antibiotics, we report the synthesis and antimicrobial studies of 30 new pyrazole derivatives. These novel molecules have been synthesized by using readily available starting materials and benign reaction conditions. Some of these molecules have shown activity with MIC values as low as 0.78?µg/mL against four bacterial strains; Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis, and Acinetobacter baumannii. Furthermore, active molecules are non-toxic to mammalian cell line.

     

Novel compounds with potent CDK9 inhibitory activity for the treatment of myeloma

Cyclin-dependent kinases (CDKs) and Polo-like kinases (PLKs) play key role in the regulation of the cell cycle. The aim of our study was originally the further development of our recently discovered polo-like kinase 1 (PLK1) inhibitors. A series of new 2,4-disubstituted pyrimidine derivatives were synthesized around the original hit, but their PLK1 inhibitory activity was very poor. However the novel compounds showed nanomolar CDK9 inhibitory activity and very good antiproliferative effect on multiple myeloma cell lines (RPMI-8226).