河北省绿子叶黑豆种质资源表现型和ISSR标记遗传多样性分析

为了揭示河北省绿子叶黑豆种质资源的遗传多样性,为其研究利用提供理论根据,以46份原产河北省的绿子叶黑豆种质资源为试验材料,对其基于表型性状及ISSR标记鉴定结果进行了聚类分析,结果表明:7个ISSR引物共检测出60个等位变异,平均每个位点有8.6个等位变异,变幅为5～17个;ISSR引物的多态性信息量PIC变幅为0.721～0.927,平均0.820;利用表型性状和ISSR标记数据进行品种间遗传多样性分析,遗传相似系数变化范围分别为0.07～0.53和0.43～1.00,平均为0.284和0.704,遗传相似性变幅较大,河北省不同绿子叶黑豆品种间存在着丰富的遗传多样性。聚类结果显示,类群与品种来源地有关。     

设施用厚皮甜瓜品种SSR标记遗传多样性分析

使用分布于甜瓜12条染色体上的72对SSR引物,对我国中东部设施内栽培的30个厚皮甜瓜品种进行分析;56对SSR引物在30个品种间表现为多态性。共检测到138个等位变异,每对引物的等位变异数变幅为2～6个,平均为2.6个。有效等位变异为86.16个,平均为2.25。每个SSR位点的多态性信息量(PIC)变化范围为0.045～0.725,平均为0.390。30个品种间遗传相似系数变幅为0.274～0.974之间,平均值为0.665,且90.4%的供试品种其遗传相似系数在0.474～0.824之间,亲缘关系较近;以遗传相似系数为原始数据,按UPGMA方法将30个品种划分为3大类群,结合系谱分析结果表明,我国中东部设施适宜种植的甜瓜品种遗传多样性不够丰富,多数品种间的亲缘关系较近,欲进一步提高中东部地区设施甜瓜产量和品质还需要拓宽亲本选择范围,扩大遗传背景。     

部分耐盐小麦品种(系)SSR位点遗传多样性研究

选择有多态性的32对SSR引物对80个小麦耐盐品种(系)进行遗传差异研究,共检测出155个等位变异,平均每个位点上有4.75个等位变异;供试80份耐盐小麦品种(系)来源广泛,遗传基础丰富,表现出较高的遗传多样性,遗传相似系数范围在0.26～0.81;聚类分析结果显示,冬性小麦品种(系)聚为一大类;春性小麦品种(系)也聚为一大类;一些系谱相同或相近的品种(系)遗传相似系数较大;A、B、D基因组中SSR位点平均等位变异差异不大,以B基因组较高.     

宁夏60份粳稻种质资源遗传多样性分析

试验用SSR分子标记对60份宁夏粳稻种质资源进行遗传多样性分析。103对SSR引物表现多态性的有58对,共扩增出212条多态性条带,等位变异范围为2～9,平均每对引物3.7个;多态性信息含量(PIC)变幅为0.032～0.788,平均为0.403;高多态性位点主要发生在3号、6号和11号染色体上,而无多态性或低多态性位点主要发生在1号和10号染色体上;成对供试材料的遗传相似系数GS值变幅为0.642～0.958,平均为0.790,单个供试材料的平均GS值变幅为0.710～0.816,平均为0.781,亲缘关系较近;UPGMA聚类表明,在遗传相似系数约0.785处,供试材料可被分为11类,大部分材料被聚在一类中。     

河北省大豆推广品种遗传多样性分析

利用主要农艺性状以及SSR和AFLP2种分子标记,对河北省41个大豆推广品种进行遗传多样性分析,以便为种质资源利用和创新提供依据。农艺性状聚类结果将41个材料划分为3个类群和2个特殊品种,聚类结果与材料系谱来源相差悬殊,不能反映材料间亲缘关系。SSR和AFLP数据聚类结果将41个材料划分为4个SAG（SSR and AFLP—basedgroups）分子类群。30对SSR引物共检测出135个等位变异,平均每个位点上有4．47个等位变异,SSR的遗传多样性指数（Simpson）分布范围为0．0928～0．7800,平均值为0、6442。10对AFLP引物共扩增出93个多态性标记,平均每对引物9．3个多态性标记。品种间的遗传相似系数（GS）变化范围为0．5877～0．9868,平均值变化范围为0．6732～0．7653,总体平均值为0.7237,遗传相似系数较高,说明材料间遗传变异较小。     

基于SSR标记分析大豆疫霉根腐病抗源的遗传多样性

丰富的遗传多样性可为大豆育种提供宽阔的遗传基础,本研究基于35对SSR标记,对60份东北地区大豆疫霉根腐病抗性品种进行了遗传多样性分析,共检测到189个等位基因,平均每个位点等位变异数5.4个,多态性信息含量指数(PIC)为0.1550~0.8195,平均为0.6636;遗传相似系数的变异范围为0.31~0.74。利用5对高多态性SSR引物构建了60份抗性材料的指纹图谱,这5对SSR引物构建的指纹图谱可以将60份疫霉根腐病抗性材料逐一区分开。采用NTSYS2.10基于遗传距离的聚类分析,将60份抗性材料分为7个类群,其中78.33%的抗性品种(系)的遗传相似系数在0.45~0.74间,表明遗传差异相对较窄,品种间遗传多样性水平较低。聚类分析与群体遗传结构分析结果有部分重合,均反映出不同地区的抗性材料间存在一定的渗透和交流。     

黄淮麦区小麦品种(系)的ISSR位点遗传多样性分析

选用11个ISSR引物,对黄淮麦区96个小麦推广品种（系）进行遗传多样性分析。共检测到96个多态性位点,每个引物多态性位点数平均为8．7个,变幅为3～23个;ISSR引物的多态性信息含量PIC变幅为0．601～0．941,平均0．791,表明ISSR具有较强的品种间区分能力,是研究小麦种质资源遗传多样性的有效分子标记技术之一。96个品种（系）间,Nei’s遗传相似系数变化范围为0．53～0．91,平均为0．60,品种间遗传相似性变幅较大,表明黄淮麦区不同小麦品种（系）间存在着不同程度的遗传多样性差异。根据品种间遗传相似系数聚类,96份材料被聚成8大类群,共14个亚类,类群与系谱和原产地无关。     

河北区试小麦品种(系)DNA指纹图谱构建及遗传差异分析

采用42个SSR标记为2009-2013年河北省区域试验的70份小麦品种(系)构建DNA指纹图谱,进行遗传差异分析,为小麦品种改良和种质资源创新提供参考。结果表明,42个SSR标记在70份品种(系)中共检测到303个等位变异,单个SSR位点的平均等位变异为7.21个,PIC值平均0.69;基因多样性平均0.73,遗传相似系数变化范围为0.05-1.00,平均0.28;表明参加河北省区域试验的品种(系)间存在不同程度的遗传差异。聚类分析把70份品种(系)划分为4大类,6个亚类,表明同一育种单位或地区品种(系)遗传背景相近,应该加大外来小麦种质资源的引进和利用力度。     

应用SSR标记分析大豆种质资源的遗传多样性

利用SSR分子标记分析了119个大豆品种的遗传多样性,结果表明：30对SSR引物在119份材料中共检测出159个等位变异,平均每对引物检测到5．30个等位变异;河北省农家品种中平均每对引物检测到5．17个等住变异,育成品种4．87个,省外品种4．93个,表明地方品种的遗传多样性高于育成品种。河北省农家品种、育成品种和省外育成品种依据SSR数据获得的品种间相似系数总体平均值相近,分别为0．698、0．698、0．672,但河北省农家品种较育成品种具有较大的变化幅度。119个品种可被划分为3个类群,在一定程度上能把育成品种和农家品种分开,并反映了一定的品种地域来源。     

基于SSR标记的六倍体小黑麦遗传多样性分析

采用已筛选出的多态性较好的分布于六倍体小黑麦21对染色体上的100对SSR引物对从国际玉米小麦改良中心(CIMMYT)引进的339份六倍体小黑麦进行了遗传多样性分析。结果显示,100对引物共检测出323个等位变异,变幅是1~6个,平均等位变异丰富度为3.23;多态信息含量(PIC)的变幅为0~0.748,平均多态信息含量为0.465;平均遗传多样性指数(H')为0.1439,说明供试的339份六倍体小黑麦品种的SSR遗传多样性较为丰富。同时基于Nei's遗传距离对339份材料进行聚类分析,可以将供试材料分为6个类群。其中,第Ⅵ类群与其他类群的遗传距离较大、遗传差异较明显。研究结果为将六倍体小黑麦的优良基因应用于普通小麦的遗传改良提供了理论依据。     

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.