二化螟人工饲养技术

二化螟Chilo suppressalis(Walker)是我国水稻上的重要害虫,为促进其防控技术研究,迫切需要建立二化螟标准化饲养技术。根据二化螟对关键营养成分的需求,研制了一种适合其生长发育、存活和繁殖的人工饲料配方,并发展了其长期、继代、规模化饲养的标准饲养技术。已用该饲料配方和饲养技术连续饲养二化螟69代,其适合度指标仍保持较高水平。该饲料配方和饲养技术适合二化螟的周年继代和规模化饲养,同时也为其它寡食性昆虫人工饲料的研制与开发提供借鉴和参考。     

二化螟人工饲料关键因子的优化及其优化配方的饲养效果

采用5因子4水平正交试验,将作者在以前筛选出的二化螟Chilosuppressalis(Walker)人工饲料的5个关键因子进行了进一步的优化,并得出了二化螟人工饲料的优化配方,其成分如下:稻茎粉18.75g、大豆粉15.00g、麦芽粉15.00g、稻糠粉6.25g、茭白茎粉7.50g、干酪素10.00g、酵母粉18.75g、纤维素7.50g、蔗糖15.00g、葡萄糖7.50g、维生素C7.50g、复合维生素B3.00g、胆固醇0.375g、氯化胆碱0.25g、Beck氏盐2.50g、山梨酸1.35g、琼脂13.49g和自来水809.25g。通过连续3代继代饲养试验,比较了该优化配方和二化螟天然饲料水稻茎的饲养效果。结果表明,在一些关键指标上(如存活率、化蛹率和羽化率等),所优化的二化螟人工饲料配方的饲养效果明显的好于其天然饲料水稻茎的;而在许多其它的指标上(如蛹期、成虫期、产卵量、卵期和孵化率等),该优化配方对二化螟的饲养效果与水稻茎的相当;但该配方饲养的二化螟在第3代时幼虫历期明显的比水稻茎的有所延长。     

二化螟人工饲料研究初报

在温度为(29±1)℃,相对湿度为80%~90%的条件下,分别以3种人工饲料和天然饲料(新鲜水稻茎杆)对二化螟Chilo suppressalisWalker进行连续继代饲养。结果表明,3种人工饲料饲养的二化螟幼虫的生长历期、化蛹率、蛹重、蛹期及羽化率等均与天然饲料的基本接近,而且这3种人工饲料配制简便、成本较低,也不易霉变,是3种较为理想的人工饲料。通过第2代和第3代的继代繁殖表明,3种人工饲料和天然饲料饲养的二化螟的发育情况都稍有下降,但3种人工饲料与天然饲料间不存在显著差异。     

草地贪夜蛾室内人工饲养技术的研究

草地贪夜蛾Spodoptera frugiperda(J.E.Smith)是一种跨国迁飞性农业重大害虫,目前已入侵我国24个省并对多种农作物造成严重危害。研发草地贪夜蛾标准化饲养技术对开展其防控技术研究及生物学相关基础研究至关重要。通过对草地贪夜蛾室内饲养,从饲养器皿、人工饲料组分、饲养方法及流程、注意事项等方面总结了一套简便实用、长期规模化饲养的标准饲养技术。已利用该标准饲养技术连续饲养草地贪夜蛾5代,其各项生命指标仍保持较高水平。该饲料配方和饲养技术适合草地贪夜蛾的规模化饲养,同时也为其它夜蛾科害虫规模化饲养提供参考。     

大螟人工饲养技术的初步研究

利用大豆粉、玉米粉、麦胚和鲜茭白等成分配制了大螟Sesamia inferens(Walker)的半合成人工饲料,利用该饲料配方,发展了大螟的长期、继代饲养技术,即初孵-2日龄幼虫在茭白上饲养,3日龄-化蛹在人工饲料上饲养。利用该方法连续饲养大螟3代,幼虫的发育历期、蛹重、幼虫存活率、化蛹率、羽化率、卵孵化率和单雌产卵量等生活史参数与在天然饲料茭白上饲养的大螟相比,二者没有任何显著差异。而且利用该方法饲养,成本低、省工省力,能显著减少病原菌的感染。这说明该饲养技术适于大螟种群的长期、继代饲养。     

人工饲料、转Bt水稻及其亲本稻苗饲养下二化螟种群适合度的比较研究

以人工饲料、转Bt水稻"克螟稻"(cry1Ab纯和基因型)及其对照亲本"秀水11"稻苗为供试寄主植物开展二化螟Chilo suppressalis(Walker)1～5龄幼虫的室内饲养试验,以明确不同龄期二化螟种群的生活史参数。试验结果表明:二化螟在低龄时死亡率最高。克螟稻对二化螟各个龄期表现出高抗性,其各个龄期在克螟稻上均不能化蛹,随着龄期的增加二化螟的耐受性增强。以秀水11和人工饲料饲养二化螟对其蛹期、成虫期、单雌产卵量、羽化率的影响无显著性差异,以人工饲料饲养的二化螟蛹重显著高于以秀水11饲养的二化螟的蛹重,蛹重与人工饲料饲养时间呈正相关。与秀水11幼苗相比,人工饲料饲养下有利于二化螟雌虫的分化。     

草地贪夜蛾人工饲料及饲养条件的优化

改良草地贪夜蛾Spodoptera frugiperda(J.E Smith)人工饲料配方及优化饲养条件,为草地贪夜蛾室内批量饲养奠定基础。利用不同人工饲料配方及制作工艺、不同温湿条件、对草地贪夜蛾进行群体饲养,研究其对草地贪夜蛾生长发育及繁殖的影响,并开展不同产卵介质对草地贪夜蛾成虫产卵量及卵孵化率的影响。结果显示,在温度27℃±0.5℃、相对湿度70%±5%、光周期L∶D=16 h∶8 h的人工气候箱中,采用饲料配方4进行幼虫群体饲养的效果最好,其发育历期最短,仅为27.1 d,幼虫存活率高达83.8%,化蛹率为91.2%,雌雄性比为1∶1.08,单雌产卵量为836粒。另外,草地贪夜蛾幼虫最喜食加热20 min的饲料,成虫于粉色塑料纸上产卵量最大。该饲料配方非常适宜草地贪夜蛾室内饲养,优化的饲养条件也为其室内规模化饲养提供参考。     

豇豆荚螟人工饲料的初步研究

本文以绿豆粉、长豇豆粉、酵母粉、多维葡萄糖、琼脂、山梨酸和甲醛为原料配制了6种人工饲料饲养豇豆荚螟Maruca testulalis Geyer,以改进其人工饲料的饲养效果。结果表明：以绿豆粉和长豇豆粉为主要原料配制的配方5和配方6饲养效果较好。尤其是配方6,豇豆荚螟的幼虫存活率和历期、蛹重和化蛹率、成虫羽化率与天然饲料饲养的豇豆荚螟相比没有差异,表明该人工饲料可用于室内人工饲养豇豆荚螟。     

甜菜夜蛾人工饲料的进一步研究

作者曾报道了一种可较理想饲养甜菜夜蛾幼虫的人工饲料配方 ,但利用该饲料连续饲养甜菜夜蛾 7代后 ,卵孵化率则从第 1代的 89.1 %下降为 6 5 .5 % ,且保持该孵化水平至第 1 1代 ,1 2代后 ,卵孵化率进一步下降。为解决以上问题 ,本实验室对配方作了进一步研究。研究表明 ,在饲料中再添加 5种可促进甜菜夜蛾生长发育的微量物质 ,即可有效阻止甜菜夜蛾因连续继代而出现卵孵化率迅速下降的问题。经实验 ,利用改进后的人工饲料连续饲养甜菜夜蛾9代 ,卵孵化率仍达 80 %以上 ,比原配方相应代数的孵化率提高 1 5 %左右 ,而且其它各测定指标如 :幼虫…     

人工饲养棉铃虫的几个问题

随着害虫防治研究的深入发展,需要大量生育一致的昆虫用于提取和鉴定性激素、释放辐射昆虫、生产病毒虫以及微生物和化学农药的筛选等。以在由于应用自然奇主作为饵料,有它的局限性和季节性,限制了研究工作的进展。近些年来应用人工饲料饲养昆虫,已有了不少的报道,取得些进展,我们自1974年对棉铃虫的人工饲料进行了研究,起初曾应用略作加工的天然食料,随后逐步研究其营养物质如蛋白质、碳水化合物、糖类、维生素、纤维素、盐类等不同配方,力求其饲养健壮,成本低廉,配方简便的人工饲料,几年来初步取得成效。在人工饲料饲养棉铃虫的过程中,曾遇到些技术性问题,例如饲养环境消毒避免有害微生物的污染,如何打破滞育,雌雄蛹羽化时间吻合及光照对成虫交尾产卵影响等问题。通过不断研究和改进,逐步得到了克服,本文就人工饲料研制配方及在饲养中的一些技术问题,作一介绍提供参考。     

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.