紫云英ISSR引物的筛选及PCR反应体系的优化

以紫云英为研究材料,用哥伦比亚大学(UBC)公布的100条ISSR引物和11种株系紫云英品种的DNA为模板进行PCR扩增,筛选出33条扩增条带较好的ISSR引物,对其中的ISSR引物进行梯度PCR,筛选出最佳的退火温度。再采用正交试验和单因素试验相结合的方法对紫云英ISSR-PCR反应体系的5种因素(模板、Mg2+、TaqDNA聚合酶、dNTP及引物)进行优化浓度。确立了适合紫云英的ISSR分析的反应体系。在25μl反应体系中,其反应浓度为:DNA模版50.00ng,Mg2+2.00mol/L,Taq聚合酶1.0 U,dNTP 0.25mmol/L,引物0.20μmol/L,2.5μl 10×buffer。本试验为以后利用ISSR技术进行紫云英遗传多样性分析和物种保护奠定了技术基础。     

胡麻专化型尖孢镰刀菌ISSR-PCR最佳反应体系的建立

采用正交试验设计原理,对尖孢镰刀菌ISSR-PCR反应体系中的5种主要因素进行优化筛选,确立了适合尖孢镰刀菌ISSR分析的反应体系,即25μL PCR反应体积中合有20 ng模板DNA、1 U Taq酶、0.4 μmol/L引物、0.2 mmol/LdNTPs、4.0 mmol/L Mg2+和2.5 μL 10 × buffer.PCR反应最佳退火温度根据引物而定,在此基础上筛选出12条扩增稳定、多态性丰富的ISSR引物.此研究为今后利用ISSR技术分析尖孢镰刀菌遗传多样性和群体结构奠定了基础.     

齿裂菌属和皮下盘菌属ISSR-PCR最佳反应条件的研究

在利用ISSR技术分析齿裂菌属和皮下盘菌属遗传多样性的研究中,为获得条带清晰、重复性好的ISSR扩增结果,对影响ISSR-PCR的条件进行了筛选,确定了此类菌物ISSR-PCR反应的最适宜条件:在15μLPCR反应体系中,10倍Taq酶缓冲液1.5μL,DNA模板8ng/μL,MgCl22.5mmol/L,dNTP0.15mmol/L,引物浓度0.4μmol/L,Taq酶1.00U,ddH2O9.0μL。最佳退火温度因不同的引物而定,最佳循环次数为35次。     

野生毛木耳ISSR-PCR反应体系的建立与优化

为获得条带清晰,重复性好,多态性高的野生毛木耳ISSR扩增结果,通过单因子试验对ISSR-PCR反应条件进行了优化。确定了ISSR分析的最佳PCR条件:25μL反应体系中模板DNA25ng、dNTPs0.24mmol/L、Taq DNA聚合酶1U、Mg2+0.9mmol/L、引物2μmol/L、10×PCR buffer2.5μL、ddH2O12.6μL。最佳退火温度因不同的引物而定,最佳循环次数为35次。在此基础上初步筛选出25条扩增稳定、多态性丰富的ISSR引物。这一优化体系的建立为进一步利用ISSR标记技术进行野生毛木耳种质鉴定及遗传多样性分析提供了一个适合的程序。     

濒危药用植物厚朴ISSR引物筛选及反应条件的优化

以厚朴DNA为模板,利用正交试验分别对影响厚朴ISSR-PCR反应的Taq酶浓度、dNTP浓度、引物浓度、Mg~(2+)浓度、模板DNA浓度进行了优化,并通过梯度PCR确定不同引物的最佳退火温度和循环次数,最终确定厚朴最佳反应体系及扩增条件为:25μl 体系,其中包括1.5 mmol·L~(-1) MgCl_2,0.3 μmol·L~(-1)引物,0.04 U·μl~(-1)Taq 酶,0.2 mmol·L~(-1) dNTP,4 ng·μl~(-1)模板DNA,1 × Buffer;扩增程序:94℃预变性5 min,94℃变性30 s,50℃～60℃(退火温度随引物不同而定)退火45 s,72℃延伸90 s,共40个循环,然后72℃延伸8 min,4℃终止反应.此外,还利用优化的反应体系成功筛选出21条ISSR引物,并利用部分引物对厚朴个体进行了遗传多样性分析.     

银杏ISSR-PCR扩增反应体系的建立与优化

目的:为了对银杏进行分子鉴定和遗传关系的分析,建立银杏ISSR-PCR的最佳扩增反应体系。方法:采用正交设计和单因素梯度实验,对影响ISSR-PCR反应体系的5个主要因素(Mg2+、dNTP、引物、模板DNA及Taq DNA聚合酶)进行筛选及优化。结果:银杏25μL ISSR最佳扩增反应体系包含10×Taq反应缓冲液、2.5 mmol/L MgCl2、0.45 mmol/L dNTP、1.2μmol/L引物(UBC861)、10 ng模板DNA及0.9 U Taq DNA聚合酶,使用此ISSR扩增反应体系,获得了10株不同性别银杏DNA的清晰条带,验证了该体系的稳定性。结论:优化的反应体系为采用ISSR分子标记技术对银杏进行遗传多样性分析、遗传育种和转基因等研究奠定了一定的理论基础。     

野生濒危植物掌叶木的ISSR-PCR反应体系的建立

以野生濒危植物掌叶木的叶片为材料,通过单因子试验分别研究了模板DNA、退火温度、TaqDNA聚合醇用量、dNTP浓度、Mg2+浓度、引物浓度等对ISSR-PCR反应的影响,找出各自的合适条件,通过各个因子的组合研究建立了适宜于掌叶木ISSR分析的扩增体系,即25μL的反应体系中含模板DNA约30ng,Mg2+2.0 mmool/L,引物0.8μmol/L,dNTP0.20 mmol/L,TaqDNA聚合酶1.5U.该研究为利用ISSR分析掌叶木遗传多样性、进行掌叶木种质资源研究等奠定了良好的基础.     

星星草RAPD-PCR反应体系建立与优化

目的:寻找一个可用于星星草(Puccinellia tenuiflora(Griseb.)Scribn.et Merr)RAPD-PCR的最适宜的反应体系。方法:利用正交设计法对影响PCR扩增效果的一些因素诸如TaqDNA聚合酶的用量、Mg2 浓度、dNTP以及引物浓度等指标进行筛选和优化。然后,通过引物对该优化结果进行验证。结果:正交设计结果表明,最适宜的PCR反应条件:20μl PCR反应体系中包括10×buffer2μl、模板DNA20ng、dNTP1.6mmol/L、TaqDNA聚合酶0.35U、引物1.0mmol/L、Mg2 1.8mmol/L。验证结果表明,该体系扩增出的条带多且清晰。结论:该研究得出的体系是适合RAPD-PCR的最适宜的反应体系,为今后星星草遗传多样性的研究奠定了基础。     

余甘子ISSR反应体系的优化

应用ISSR技术开展余甘子遗传变异分析、辅助育种、品种鉴定、系统进化等研究,以(TC)8C为引物,采用正交设计和单因素试验,研究余甘子基因组DNA的浓度、退火温度、引物浓度、dNTP浓度、Taq DNA聚合酶用量对余甘子ISSK-PCIR反应的影响,建立并优化了适宜于余甘子ISSK分析的扩增体系:20μl的反应体系中采用25ng的模板DNA、0.35μmol/L ISSR引物、1.25U Taq 酶,0.3mmol/L dNTPs,引物(TC)8C的最佳退火温度为51.7℃.     

节瓜ISSR-PCR反应体系的建立与正交优化

旨在开展节瓜种质资源分类鉴定与遗传多样性研究。通过正交试验设计与单因素分析相结合的方法,对节瓜ISSR-PCR反应体系5个因素(模板DNA浓度、dNTP浓度、Mg2+浓度、引物浓度与Taq聚合酶浓度)在4个水平上进行优化分析,建立了节瓜稳定可靠且具丰富多态性的最佳反应体系,进而对引物退火温度进行梯度试验分析。结果表明,20μL节瓜ISSRPCR最佳反应体系为70 ng模板DNA、0.2 mmol/L dNTP、1.2 mmol/L Mg2+浓度、0.96μmol/L引物、0.8 U Taq DNA聚合酶和2.0μL10×buffer;引物IS807最佳退火温度为53℃。以此为基础,利用4条引物对4份节瓜种质进行最佳反应体系稳定性验证,证明该体系稳定可靠、扩增谱带清晰、多态性丰富且重复性较好。     

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.     

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     

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.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

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.     

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).     

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.