中国啤酒大麦品种RAPD标记的遗传多样性分析

采用RAPD技术对中国38个啤酒大麦品种的遗传资源进行了聚类分析。结果表明：从筛选出的28个有多态性的随机引物中,共扩增出153条谱带,其中91条谱带具有多态性,占59．4％。每个引物可扩增出1～8条多态性谱带,平均3．3条。聚类分析表明,在遗传距离GD值0．27水平上38个啤酒大麦品种可聚成两大类,下分5个亚类。品种间遗传距离GD变幅为0．00952～0．37846。RAPD标记揭示出这38个啤酒大麦品种遗传变异较小,遗传基础比较狭窄。     

利用RAPD和ISSR标记分析烤烟品种间遗传关系

利用RAPD和ISSR标记对22份烤烟(Nicotiana tabacumL.)品种进行了遗传关系研究。在RAPD分析中筛选到13个引物,共扩增出167条带,其中多态性带50条,多态性比率为29.9%;在ISSR分析中筛选出7个引物,共扩增出96条带,其中多态性带44条,多态性比率为45.8%。两种标记相结合估算出的品种间遗传相似系数在0.881~0.979之间,平均为0.933。单独基于RAPD标记和ISSR标记的聚类结果有一定差异;两种标记结合起来的聚类分析结果与系谱信息吻合程度更高。定向选择可能对烤烟品种间遗传关系有较大影响;国外引进品种与国内育成品种并未完全分开,表明分子水平的遗传关系和地理来源间缺乏必然联系。     

利用SSR与RAPD分子标记评估甘蔗品种的遗传多样性

利用SSR与RAPD两种分子标记对美国、中国台湾以及中国大陆不同甘蔗育种单位选育的甘蔗品种或亲本材料的遗传多样性进行评估。其中19对SSR引物共扩增出87条带,多态性带为84条,多态性比例为96.55%,扩增出的条带数范围为2~8条,平均每对引物扩增出4.58条带,引物的PIC值范围为0.34~0.93,平均0.64。21条RAPD引物共扩增出184条带,扩增条带数范围为3~16,平均每条引物扩增8.76条带,其中多态性带为184,多态性比例为100%,引物PIC范围为0.53~0.97,平均0.86。结果表明,两种分子标记都能较好的评估甘蔗品种的遗传多样性。     

利用RAPD标记分析大麦种质资源的遗传多样性

利用RAPD标记对19份西藏近缘野生大麦材料、33份我国不同省市的地方品种以及8份国外引进大麦品种共60份大麦种质资源的遗传多样性进行检测.结果表明材料间遗传差异明显.32个RAPD引物中,有25个引物(占78.13%)可扩增出清晰且具多态性的条带,另外7个引物能扩增出1～3条清晰但无多态性的条带.每个引物可扩增出1～8条多态性带,平均为3.72条.32个引物共产生119条DNA片段,其中87条具有多态性,多态性比率(PPB)为73.11%,平均多态信息量(PIC)为0.434;每个位点平均有效等位基因数(Ne)为2.304;材料间遗传相似系数GS变化范围为0.757～0.981,平均值为0.871.19份来源于西藏的近缘野生大麦材料间GS值变幅为0.818～0.969,平均为0.892;33份我国栽培大麦地方品种间的GS值变化范围为0.783～0.981,平均为0.879;8份分别来自8个国家的栽培大麦品种间的GS值变幅为0.820～0.956,平均为0.882.根据RAPD标记分析的结果,对60份大麦种质资源进行聚类分析,在平均GS值0.871水平上60份大麦材料可聚为5类,聚类结果能在一定程度上反应材料的地理分布关系,但某些相同地理来源的材料也较分散地分布在整个聚类树中.本研究从分子水平上进一步证明了我国栽培大麦丰富的遗传多样性,是世界栽培大麦的遗传多样性中心之一.     

中国北部高原地区谷子品种遗传差异的SSR分析

选用60对谷子SSR分子标记,对中国北部高原生态区6个谷子农家品种和14个谷子育成品种的遗传差异进行分析.结果表明: 60对谷子SSR引物中,只有7对引物扩增出了特异性条带;7对引物共检测出19条特异性带,平均每对引物检测出2.71条带.引物AC408-2检测出的特异性带最多(5条),引物P24检测出的特异性带最少(1条).基于SSR分子标记的聚类结果表明,品种间的遗传距离介于0.11～0.86,20个品种可归为四大类,其中6个农家品种分别归属于三大类中,农家品种遗传变异较育成品种大.     

利用RAPD标记评价小豆种质遗传多样性

本研究利用10个RAPD引物对180份小豆种质的基因组DNA进行扩增,共扩增出44条带,其中35条具有多态性,比例为79.5%,平均每个引物扩增出3.5条多态性带;平均遗传距离为0.274,变异幅度为0.05～0.60,平均遗传多样性指数为0.692;基于RAPD标记,把180份小豆种质聚类划分为4个组群,该组群的划分与小豆的生态地域性似乎不存在明显的相关性.     

应用RAPD标记分析黑麦属品种的遗传多样性

四川农业大学小麦研究所侯永翠、郑有良、魏育明等研究人员对黑麦遗传多样性课题作了研究。他们采用随机扩增多态性DNA(RAPD)标记 ,对黑麦属 (SecaleL) 7个品种共 1 2份材料进行了遗传多样性检测 ,发现被检测材料间RAPD标记多态性较高 ,在 4 0个随机引物中 ,有 2 5个引物约占整个的 6 2 .5 %的扩增产物具有多态性。这 2 5个中共扩增出 1 6 7条带 ,其中 89条带约占 5 3.2 %具有多态性 ,每个引物可扩增出 1～ 1 0条多态性带 ,平均为 3～ 6条。RAPD标记遗传距离GD变异范围为 0 .1 382～ 0 .4 5 1 2 ,平均为 0 .2 71 2。通过聚类分析表…     

乌塌菜种质资源遗传多样性的ISSR分析

利用ISSR技术对48份乌塌菜种质资源进行遗传多样性分析。从60条随机引物中筛选出稳定性强、条带清晰且多态性丰富的9条引物进行PCR扩增,共扩增出103条谱带,平均每个引物扩增出11.4条带,其中多态性带85条,多态性位点百分率为82.68%。不同乌塌菜种质间遗传相似系数变幅为0.59~0.97,说明ISSR标记能够揭示材料间较高的遗传多样性。利用UPGMA聚类分析,ISSR标记能将48份乌塌菜品种完全区分开,48份乌塌菜种质被划分为4个类群,聚类结果与叶片颜色相关,为乌塌菜品种资源的研究利用提供参考。     

16份石榴RAPD扩增产物的两种电泳方法检测及其序列特征

本实验以16个石榴品种为实验材料,筛选出10个重复性及多态性均较好的引物进行RAPD分析。分别采用琼脂糖凝胶以及聚丙烯酰胺凝胶(PAGE)电泳检测方法对PCR扩增结果进行检测并对其结果进行比较,结果显示,两种电泳方式均能得到较为清晰的扩增条带,且两种电泳方式获得的条带总数及多态性条带数均有所不同,琼脂糖凝胶电泳方法共检测出76条带,其中有43条为多态性谱带,多态性比率为56.4%;而在PAGE电泳方法共检测出123条谱带,多态性谱带数为87条,多态性比率为70.95%。PAGE电泳方法检测出的条带数约为琼脂糖凝胶电泳方法检测出条带数的1.5倍。基于两种电泳方法所得RAPD标记的多态性位点,利用NYSYS软件计算遗传相似系数,并构建遗传关系聚类图,分析结果显示,石榴遗传多样性丰富,两种电泳方法所得聚类结果大致相同,可以利用RAPD分子标记及两种电泳检测方法对不同数量的石榴进行分子水平的品种鉴定和遗传多样性的分析。同时通过对来自几个引物随机挑选的17个片段进行克隆,测序结果显示17个片段都是对应引物的RAPD扩增产物,其中有3条是编码蛋白的基因片段,表明了RAPD不仅扩增基因组上的非编码蛋白序列,同时也可以扩增编码蛋白的基因片段,这为更好地认识RAPD技术的实质以及促进石榴产业的发展提供了理论依据。     

木霉肽类代谢产物对豇豆土著根瘤菌遗传性状的影响

利用RAPD与ISSR分子标记检测手段,分析了哈茨木霉T2-16肽类代谢产物处理豇豆土著根瘤菌,对其遗传性状的影响,同时,比较了RAPD和ISSR两种不同分子标记在检测根瘤菌种间的遗传相似性以及遗传变异性的分辨力.实验中,从100条引物中筛选到具有多态性的ISSR引物5条,从80条引物中筛选到具有多态性的RAPD引物6条,用5条ISSR引物扩增出54条带,多态性条带比率为75.93 %;6条RAPD引物扩增出61条带,多态性条带比率为68.85 %.两种分子标记均能揭示出处理前后根瘤菌间的遗传差异,但ISSR标记比RAPD标记可检测到更大的遗传变异.根据两种标记的结果,对供试的根瘤菌进行聚类分析,结果表明,土著根瘤菌经木霉肽类代谢产物处理后,与出发菌株相比,表现出一定程度的遗传分化和遗传差异性.     

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.