温度对双委夜蛾种群生态学特征的影响

【目的】双委夜蛾Athetis dissimilis(Hampson)是新发现的一种农业害虫,为探索温度对双委夜蛾生长发育和繁殖的影响。【方法】在室内l6,21,26,30,34(±1)℃,RH为70%±5%、光周期为14L︰10D条件下,测定了双委夜蛾各发育阶段的发育历期、存活率及成虫产卵量,组建了双委夜蛾的实验种群生命表。【结果】结果表明,双委夜蛾各虫态的发育历期随温度的升高而缩短;世代发育起点温度(C)为9.88℃,有效积温(K)为906.53日·度;卵的孵化率在不同的温度下无显著差异;幼虫存活率、化蛹率和羽化率则以21~30℃为最高;成虫的产卵量以21~26℃为最高,而在16℃和30℃时显著降低,在34℃下成虫不能交配,30℃成虫交配率仅为46%;生命表分析表明,26℃双委夜蛾的种群趋势指数和内禀增长率取得最大值,分别为98.5和0.1。【结论】21~26℃是最适宜双委夜蛾生长发育和繁殖的温度范围。     

落叶松尺蠖Erannis ankeraria Staudinger的生物学特性

【目的】明确落叶松尺蠖Erannis ankeraria Staudinger的发生规律及生物学特性。【方法】野外调查和室内饲养。【结果】在集宁市落叶松尺蠖1年1代,以卵越冬,越冬卵在翌年4月下旬、5月上旬孵化,6月中下旬开始入土化蛹,成虫于9月初羽化、产卵。在温度为20℃,RH=70%的条件下,落叶松尺蠖幼虫期(19.96±0.86)d,预蛹期(3.93±0.95)d,蛹期(108.4±13.17)d。蛹分布于树干基部30~90cm范围内,深度4~8 cm。雄虫在6:00—8:00及12:00—16:00羽化,早于雌性,雌虫在20:00—24:00羽化,羽化若干小时后可交尾,交配持续时间20~260 min,可多次交尾。20℃下交尾雌虫寿命为(5.56±1.47)d,雄虫为(3.95±0.95)d,产卵量为(162.2±69.9)粒;不交尾雌性为(8.03±2.90)d,雄性为(4.38±1.59)d,产卵量为(164.1±81.3)粒,但卵不能孵化;15℃条件下不交尾雌雄寿命分别为(14.48±6.67)d,(6.64±1.76)d,产卵量为(145.7±76.8)粒。【结论】落叶松尺蠖危害期短,蛹期较长,雌雄成虫羽化时间有差异;温度和交尾对寿命和产卵量都有显著影响。     

温度对双委夜蛾实验种群生长发育及繁殖的影响

【目的】双委夜蛾Athetis dissimilis(Hampson)是近几年在中国大陆新发现的农业害虫,与二点委夜蛾Athetis lepigone(Mschler)形态相似,危害特点相同。明确温度对其生长发育的影响,对该害虫的预测预报和有效防控具有重要的指导意义。【方法】在光周期16L∶8D,RH 70%±10%的实验室条件下,设置17,21,25,29和33℃5个恒定温度,饲喂人工饲料,研究温度对双委夜蛾发育历期、死亡率及繁殖的影响,并计算各虫态的发育起点温度和有效积温。【结果】在17~33℃范围内,双委夜蛾均可以完成整个世代,各虫态发育历期随温度的升高而缩短;17和21℃下,双委夜蛾幼虫有7个龄期,而25℃以上时幼虫只有6个龄期。25℃下双委夜蛾死亡率最低(21.00%),单雌产卵量最高(763.95粒)。整个世代的发育起点温度和有效积温分别为9.38℃和1 015.36日·度。雌雄虫寿命和产卵期随温度的升高逐渐缩短,且各温度下雌虫寿命均较雄虫长,性比(雄雌比)均在1.18~1.20之间。【结论】25℃是双委夜蛾实验种群生长发育和繁殖的适宜温度。     

噻虫啉亚致死剂量对斜纹夜蛾解毒酶系活性与生长繁殖的影响

【目的】斜纹夜蛾Spodoptera litura(Fabricius)是一种重要农业害虫,因药物、外界环境等选择压力的不同,造成其生长发育有所差异。噻虫啉是第二代氯代烟碱类杀虫剂,对昆虫烟碱型乙酰胆碱受体有很强的激动作用。本实验旨在探讨噻虫啉对斜纹夜蛾的亚致死效应,为斜纹夜蛾的综合防治和噻虫啉的合理使用提供理论依据。【方法】采用饲料混毒法,测定噻虫啉对斜纹夜蛾3龄幼虫的毒力,确定其亚致死剂量LC25和LC50。通过离体酶活性测定,分析噻虫啉亚致死剂量对斜纹夜蛾体内羧酸酯酶、谷胱甘肽-S转移酶和多功能氧化酶3种代谢解毒酶活性的影响。记录各个年龄阶段的生长发育、繁殖力以及种群增长等数据,应用特征年龄-龄期及两性生命表方法分析LC25和LC50剂量处理和对照的斜纹夜蛾子代(F1)两性生命表参数的差异。【结果】以LC25和LC50剂量处理斜纹夜蛾3龄幼虫48 h,羧酸酯酶活性均受到明显诱导,分别升高了14.2%和45.1%;谷胱甘肽-S转移酶活性受到明显的抑制,分别降低了9.8%和37.1%;而多功能氧化酶活性均低于对照,其抑制作用与浓度成正比,但差异不显著。LC25和LC50剂量处理斜纹夜蛾幼虫后,子代(F1)的成虫前期分别比对照延长了3.05 d和4.80 d,雄成虫寿命分别缩短了2.06 d和3.31 d,雌成虫寿命分别缩短了0.13 d和0.92 d;其单雌产卵量均显著减少,分别降低了17.7%和33.3%;化蛹率分别降低了10.7%和11.4%;两个处理的内禀增长率(r)、周限增长率(λ)和净增殖率(R0)均显著小于对照,平均世代时间(T)均明显延长。【结论】羧酸酯酶可能为斜纹夜蛾对噻虫啉解毒代谢过程中的主要解毒酶,在其后续抗性形成中起主要作用;噻虫啉亚致死剂量对斜纹夜蛾的生长、发育、繁殖有显著的抑制作用。     

母代性比对甜菜夜蛾实验种群繁殖潜力的影响

【目的】探明母代性比对甜菜夜蛾Spodoptera exigua(Hübner)实验种群繁殖及后代发展趋势的影响,为短期预测预报提供科学指导。【方法】在人工气候培养箱中(设置条件:温度28±1℃,光周期为16L:8D,相对湿度为70%±5%),研究甜菜夜蛾实验种群不同母代性比结构(♀:♂=1:1,1:2,1:3)对主要繁殖参数的影响。【结果】甜菜夜蛾成虫产卵历期随母代性比下降而缩短;种群产卵量随母代性比降低而减少;孵化率随母代性比降低而升高;每雌产卵量无差异,但雄蛾对卵及后代的贡献量却随着雌蛾比例的加大而显著提高;后代性比和雌蛹蛹重有随母代性比下降而上升的趋势。【结论】母代性比除对甜菜夜蛾雌蛾个体生殖能力影响较小,对雌蛾产卵历期、种群产卵量和孵化率、后代性比、后代雌蛹蛹重及母代雄蛾生殖贡献率均有显著影响。当以性诱剂诱集的雄虫数量为依据进行短期预测预报时,除了考虑雄虫的数量外,还有必要了解此时种群的性比结构,才能做出更准确的判断。     

柳毒蛾繁殖生物学的初步观察

【目的】为了明确柳毒蛾Leucoma salicis(Linnaeus)交配的日节律高峰,温度和不同交配持续时间处理对成虫寿命、产卵量和孵化率等繁殖生物学的影响。【方法】将新羽化的柳毒蛾成虫置于养虫笼中,观察交配的日节律高峰,并统计不同温度和不同交配持续时间处理下的成虫寿命、产卵量和孵化率。【结果】成虫在羽化当晚的后半夜凌晨开始交尾,次日晚上开始产卵。成虫交配集中在羽化翌日凌晨3:00—5:00之间,高峰为4:00。产卵高峰都出现在2日龄成虫,但是,25℃下成虫交配持续时间(9.2 h)显著短于28℃(11.8 h)。交配持续时间为30、60和300 min的处理,雌成虫平均寿命显著长于对照(对照9.2 h),雄虫仅60 min的处理显著长于对照。同时,极短的交配持续时间(30 min)显著降低雌虫的产卵量和孵化率。【结论】试验明确了成虫交配的日节律高峰,在适宜的温度范围内(25~28℃),雌雄成虫的寿命、单雌总产卵量无显著差异,交配持续时间明显影响成虫寿命、产卵量和卵孵化率。     

短时高温对意大利蝗存活和生殖的影响

【目的】明确短时高温对意大利蝗Calliptamus italicus(L.)存活和生殖的影响,为气候变暖趋势下意大利蝗灾害的预测预报及综合防治提供理论依据。【方法】采集初羽化24h内的意大利蝗雌雄成虫,于30℃光照培养箱中饲养。设置4个温度处理组,分别为33、36、39、42℃,每日处理4h,之后放回30℃光照培养箱中继续饲养。未经过短时高温处理的意大利蝗为对照组。观察记录各组意大利蝗存活率、寿命、产卵前期、产卵期、单雌产卵量、卵巢发育情况及卵巢中卵黄蛋白含量,并分析变化规律。【结果】短时高温对意大利蝗成虫存活率无显著影响,但对其寿命有显著影响(P0.01),其中33℃处理4h,意大利蝗雌雄成虫寿命显著延长(P0.01),而36~42℃范围内处理4h,意大利蝗雌雄成虫寿命显著缩短(P0.01)。短时高温对意大利蝗产卵前期有显著影响(P0.05),随温度升高,产卵前期缩短,但对产卵期没有显著影响(P0.05)。短时高温对意大利蝗单雌产卵量有显著影响(P0.01),其中33℃处理组单雌产卵量为(57.6±2.4)粒,显著高于对照组(P0.01),36~42℃范围内,随温度升高单雌产卵量显著降低(P0.01)。短时高温对意大利蝗卵巢长度、鲜重及发育历期有显著影响(P0.01),但对卵巢宽度没有显著影响(P0.05),且随温度升高,卵巢长度、宽度、鲜重及发育历期均呈下降趋势。短时高温可使卵黄蛋白在卵巢中提前沉积,并对其含量(峰值)有显著影响(P0.01),其中33℃处理组卵黄蛋白含量(峰值)为(49.795±6.253)mg/mL,显著高于对照组(P0.01),36~42℃范围内处理4h,卵黄蛋白含量(峰值)显著减少(P0.01)。【结论】33℃处理4h,意大利蝗存活及生殖特性显著提高,而36℃及以上高温对意大利蝗生长繁殖产生不利影响。     

幼虫期短时高温暴露对二点委夜蛾存活和繁殖的影响

【目的】随着全球气候变暖,夏季短时极端高温发生的频率逐渐增加。本研究旨在探明二点委夜蛾Athetis lepigone幼虫期对高温的适应性。【方法】将二点委夜蛾不同日龄(1,6,12和18日龄)幼虫在不同高温(35,38和41℃)条件下暴露不同时间(0.5,1,2,4和6 h)后转移至适温(26℃)继续饲养,观察短时高温对其存活率、发育历期、化蛹率、羽化率、雌虫寿命、单雌产卵量及次代卵孵化率的影响。【结果】幼虫期短时高温暴露的温度和时间对二点委夜蛾幼虫的存活率和发育历期有显著影响,而对化蛹率、成虫羽化率、雌虫寿命、单雌产卵量以及次代卵孵化率影响不显著。随着温度的升高和处理时间的延长,幼虫存活率逐渐降低,发育历期逐渐延长。其中,18日龄的幼虫最为敏感,38℃和41℃暴露6 h后存活率分别为58.3%和17.7%,显著低于对照,发育历期分别为25.5 d和29.2 d,较对照显著延长。【结论】幼虫期经历短时高温暴露仅对幼虫的存活和发育历期有影响,而对后续蛹和成虫的生长发育及成虫繁殖力没有影响。     

变温对粘虫生殖及主要能源物质代谢的影响

【目的】明确变温与粘虫Mythimna separata(Walker)生长发育和生殖的关系及变温条件下粘虫主要能源物质代谢的变化规律。【方法】将粘虫卵置于光周期均为14L∶10D,温度分别为25℃和30℃日恒温和白天30℃、夜晚20℃日变温的条件下饲养,观察记录25℃和30/20℃下的成虫产卵及卵巢管发育情况,再取30℃和30/20℃下饲养获得的3龄幼虫、6龄幼虫、蛹和1日龄成虫,测定其糖原、海藻糖和甘油三酯3种能源物质的含量及海藻糖酶、3-磷酸甘油醛脱氢酶、3-磷酸甘油脱氢酶及3-羟酰辅酶A脱氢酶等4种主要能源物质代谢酶的活性。【结果】25℃与30/20℃饲养条件下相比,1日龄雌成虫卵巢管发育明显滞后,但单雌产卵量显著较多;蛹期糖原、海藻糖和甘油三酯的含量均高于3龄和6龄幼虫,成虫期各能源物质含量均较低。30/20℃日变温下粘虫体内供试3种能源物质的含量显著高于30℃日恒温(6龄幼虫和蛹期甘油三酯含量在两温度下无显著差异);温度变化对供试4种酶活性的影响差异显著。【结论】温度变化对粘虫的生长发育和繁殖具有显著的影响。在粘虫生长发育过程中以糖代谢为主;变温会加速糖代谢,减缓部分发育阶段的脂代谢,更有利能源物质的积累。     

根结线虫对斜纹夜蛾幼虫生长及营养利用随龄期变化的研究

【目的】为明确南方根结线虫Meloidogyne incognita侵染对斜纹夜蛾Spodoptera litura幼虫的影响是否因幼虫的龄期而异。【方法】采用被南方根结线虫侵染和未被侵染的乌桕叶片饲喂斜纹夜蛾幼虫,并测定不同龄期幼虫的生长（幼虫体重、发育历期、相对生长率）和营养利用（取食量、近似消化率、食物转化率）情况。【结果】随着幼虫龄期的增加,斜纹夜蛾幼虫的取食量及发育历期呈上升趋势,幼虫体重、相对生长率和食物转化率先上升后下降,而近似消化率则先下降后上升。与饲喂未侵染南方根结线虫的乌桕叶片相比,取食线虫侵染的乌桕叶片的斜纹夜蛾2龄幼虫近似消化率（0.78±0.07）%显著增加了约30%,但斜纹夜蛾的4龄幼虫体重（0.12±0.04）g、相对生长率（0.20±0.06）g·g^(-1)·d(-1)·d^(-1)和食物转化率（0.54±0.18）%分别降低了61%、36%和73%。线虫侵染处理与龄期互作对斜纹夜蛾的发育历期和取食量无显著影响。【结论】根结线虫侵染对斜纹夜蛾幼虫生长及其营养利用的影响因龄期而异,线虫侵染处理虽显著增加了斜纹夜蛾2龄幼虫的近似消化率,但却抑制了其4龄幼虫的生长及其营养利用。     

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.