阿尔卑斯山高山-亚高山过渡区高山黄花茅的群体遗传结构和分化研究

应用等位酶分析,在瑞士阿尔卑斯山的阿尔拜特(Arpette)和拜阿尔普(Belalp),沿三个不同的海拔梯度,研究了高山黄花茅3个自然居群的遗传变异和分化。研究结果表明,平均的多态性位点比例为64．9％,每个位点平均等位基因数为2．37,平均期望杂合性为0．252。亚居群间平均的遗传距离为0．011,发现79％的遗传变异存在于居群内。基于等位酶分析,边缘亚居群与中心亚居群似乎有类似的遗传变异性。相对比较高的遗传分化、低的亚居群间基因流和小的邻居大小值暗示,近交和随后的遗传漂变可能是导致阿尔拜特黄花茅居群遗传变异性较低的主要原因。     

黄瓜多样性固定核心样本集的构建与评价

利用149对具有多态性的In Del引物对473份黄瓜初选核心种质自交系进行遗传多样性分析。采用3种方法 12种取样比例对该初级遗传多样性固定群体进行抽样获得候选多样性固定核心样本集(GDFCC),使用等位基因数(Na)、有效等位基因数(Ne)、Shannon's信息指数(I)、基因多样性指数(gene diversity)、多态性信息含量(PIC)、总等位位点数(total number of loci)、等位位点保留百分率(retention rate of loci)评价候选多样性固定核心样本集的多样性和代表性,结果表明,采用逐级聚类+稀有基因优先取样法并按照15%取样比例构建出的多样性固定核心样本集的效果较好。比较发现,该核心样本集的Ne、I、基因多样性指数和PIC值均接近或高于初级遗传多样性固定群体,且对原始群体的等位位点的保留百分率为99.68%。入选多样性固定核心样本集的材料来自15个国家和国内18个省市。该研究为今后黄瓜优异基因资源的挖掘利用提供了代表性强、覆盖度广、遗传稳定的研究群体,将有利于黄瓜种质资源的高效研究利用。     

河北省冬小麦品种SSR标记遗传多样性分析

利用79对多态性较高的SSR引物,对河北省1997-2007年间审定的冬小麦品种及国家小麦区试抗旱对照品种晋麦47和洛旱2号,共计87个冬小麦品种进行遗传多样性分析。79对SSR引物共检测出175个等位变异位点,每对引物可产生1~6条等位变异位点,平均2.215条。标记位点多态性信息含量(PIC)变幅为0.824~0.998,平均为0.941;有效等位基因数(Ne)变幅为1.644~20.333,平均4.708;香农指数(H’)变幅为0.148~1.102,平均为0.544,说明河北省冬小麦品种SSR遗传多样性较低。品种间遗传相似系数(GS)变幅为0.184~0.899,平均为0.418,其中河农826与石家庄8号间的遗传相似性最高,GS高达0.899,71-3与藁优9618间的遗传相似性最低,GS为0.184。不同育种单位培育的小麦品种平均遗传相似系数存在较大差异。UPGMA遗传相似性聚类表明,石家庄市小麦新品种新技术研究所培育的小麦品种与其他单位品种存在较大的遗传差异。     

棉铃虫地理种群的等位酶变异

利用聚丙烯酰胺梯度凝胶电泳检测了棉铃虫Helicoverpa armigera的13种等位酶：α-磷酸甘油脱氢酶(α-GPDH)、酸性磷酸酯酶(ACPH)、碱性磷酸酯酶(ALP)、醛氧化酶(AO)、酯酶(EST)、谷氨酸草酰乙酸转氨酶(GOT)、己糖激酶(HEX)、亮氨酸氨肽酶(LAP)、乳酸脱氢酶(LDH)、苹果酸脱氢酶(MDH)、苹果酸酶(ME)、磷酸葡萄糖变位酶(PGM)和黄嘌呤脱氢酶(XDH),染色采用双染法。对其中9种等位酶的遗传变异进行了分析,包括13个位点,6个位点表现出多态性,7个位点是单态的,其中多态性位点比例为46.15%。AO、GOT、LAP、LDH、ME和XDH计算出棉铃虫的平均杂合度为0.1160,南京、成都、武穴、衡阳和哈密5个种群的平均遗传距离为0.0008～0.0293,平均遗传相似度为0.9707～0.992。棉铃虫种群内存在很高的遗传多态性,而已测定的种群间遗传分化程度较小,种群间没有基因交流的障碍。迁飞阻碍了不同地理种群间的遗传分化。     

亚洲小车蝗不同地理种群遗传多样性的等位酶分析

采用等位酶电泳技术对亚洲小车蝗8个地理种群遗传多样性和遗传分化进行了研究,并对8种等位酶系统:苹果酸脱氢酶(MDH)、苹果酸酶(ME)、乙醇脱氢酶(ADH)、谷氨酸脱氢酶(GDH)、谷氨酸-草酰乙酸转氨酶(GOT)、异柠檬酸脱氢酶(IDH)、腺苷酸激酶(AK)和己糖激酶(HK)进行聚丙烯酰胺凝胶电泳分析。结果表明:在亚洲小车蝗8个地理种群中共检测到14个基因位点,其中7个位点为多态位点,检测到25个等位基因;种群总体水平多态位点比率P=42.86%,平均有效基因数A=1.786,平均期望杂合度He=0.072,种群平均遗传距离为0.069～0.235。聚类分析表明,遗传距离与地理距离存在一定相关性。亚洲小车蝗8个种群的遗传分化系数Fst=0.086,基因流Nm=3.142,表明亚洲小车蝗种群间有一定程度的遗传分化及基因交流。     

欧洲中部刺槐种源群体等位酶变异研究

从欧洲中部及美国收集了18个刺槐种源种子,以2年生苗木为材料,采用水平切片淀粉凝胶电泳和聚丙烯酰胺凝胶电泳对11个酶系统进行了检测,共发现20个酶位点,其中14个为多态位点,多态性位点百分数为70％。在参加计算的7个酶系统的12个多态性位点中,平均每个位点的等位基因数(A)和平均每位点等位基因有效数(Ae)为2.733和1．794,平均每个位点的实际杂合度(Ho)和预期杂合度(He)为0．368和0．400,固定指数(F)为0．080,绝大多数位点固定指数为正值。各基因位点遗传参数与12个位点平均值进行相关分析表明,Fe-6和Lap-a的大部分群体遗传参数(A、Ae、Ho、He等)与平均值存在紧密的相关关系,其他位点各项遗传参数和总平均值相关不明显,这些位点的重要性可能比相关性较好的位点更大。德国8个种源群体间遗传距离变化在0．09-0．26之间,来自匈牙利的6个种源之间遗传距离很小,绝大部分均在0．11以下;德国的8个种源与匈牙利和斯洛伐克的8个种源之间的遗传距离变化在0．09-0．24之间;来自美国的2个种源,与欧洲的种源间的遗传距离在0．09-0．23之间,这一距离没有超出欧洲种源之间的差异。匈牙利和斯洛伐克的8个种源群体的各项遗传参数均高于德国种源,表明这两个国家的遗传多样性水平较高。同时来自这两个国家的种源群体间变异系数变化在2．92％-9．97％,说明群体之间的遗传差别很小。德国的8个种源群体各项遗传参数相对较低,但群体间变异系数较高,群体间遗传差别较大。以各个国家为群体单位,4个群体间各项遗传参数的变异均较小,变异系数变化在3．861％-5．139％,表明刺槐种源间地理变异模式不明显。     

利用RAPD和ISSR分子标记分析地黄种质遗传多样性

用RAPD与ISSR技术对地黄的8个品种和2个脱毒品系进行了种质遗传多样性分析.分别从80条RAPD引物和44条ISSR引物中筛选出适合地黄种质分析的17条RAPD引物和10条ISSR引物用于RAPD和ISSR分析.17条RAPD引物共扩增出177条带, 多态性位点数为109; 多态性位点比率为61.58%;平均多样性指数(I)为0.3135;每个位点的有效等位基因数(Ne)是1.3641; 10条ISSR引物共扩增出110条带. 多态性位点数为79; 多态性位点比率为71.58%;平均多样性指数(I)为0.3577;每个位点的有效等位基因数(Ne)是1.4037. 基于扩增条带数据库建立了各自的Jaccard遗传相关系数矩阵,构建了相似的分子树状图,将10个供试材料分为2类:一类群含组培85.5、大田85.5、组培9302、大田9302、金状元和金白6个材料;另一类群含北京1号、大红袍、地黄9104和野生地黄4个材料.两种分子标记的分析结果呈极显著正相关(r＝0.649).结果表明,RAPD与ISSR标记适合于地黄种质遗传多样性分析,ISSR标记技术是一种多态性和重复性优于RAPD技术的实用技术.     

新疆石榴种质资源遗传多样性的SRAP分析

采用SRAP分子标记技术,对21份新疆石榴品种的遗传多样性与亲缘关系进行分析。从36对引物组合中筛选出16对扩增条带清晰、多态性高的引物组合分析供试材料,共检测出271个位点,其中194个为多态性位点,多态性比率达71.59%,平均每对引物组合产生16.94个位点和12.13个多态性位点。21份石榴样品间的相似性系数为0.63~0.89,平均为0.77。UPGMA聚类结果显示,在相似性系数为0.776时,21份材料可被分为5个类群。新疆石榴品种间平均观察等位基因数(Na)、有效等位基因数(Ne)、Neis基因多样性指数(H)及Shannons信息指数(I)分别为1.712 2、1.352 8、0.199 9及0.310 5。研究表明,新疆喀什地区石榴品种的遗传多样性最为丰富;SRAP聚类结果与石榴的表型特征存在一致性,且SRAP分子标记技术是研究石榴遗传多样性简单而有效的手段。     

中型狼尾草种质资源遗传多样性的ISSR分析

运用ISSR标记对采自云南的25份野生种质和4份驯化新品系中型狼尾草材料进行遗传多样性分析。结果显示:(1)50条ISSR引物中共筛选出10条能扩增出清晰条带且多态性明显的引物,29份材料DNA共获得72个扩增位点,其中多态性位点62个,多态性比率为87.4%,平均每条引物扩增位点为7.2个;平均观察等位基因数(Na)、有效等位基因数(Ne)、Shannon多样性信息指数(I)和Nei’s基因多样性指数(H)分别为1.861 1、1.742 8、0.561 0和0.395 9;种质材料间的遗传相似性系数变幅为0.236~0.903,表现出丰富的遗传多样性。(2)利用UPGMA聚类分析,以遗传相似系数0.51为界,29份材料划分为4大类,但Mantel检测表明29份种质材料的遗传聚类和地理距离之间不存在显著的正相关关系(r=0.437 0,P=0.204 6)。研究结果首次从分子水平揭示了中型狼尾草的遗传多样性和变异水平,为合理地引种、驯化、保护和利用中型狼尾草野生资源提供了重要的参考依据和数据支持。     

甘肃濒危植物秦艽的龙胆苦苷含量和遗传多样性的研究北大核心CSCD

通过对不同产地秦艽的含量和遗传多样性进行研究,为甘肃秦艽的就地保护提供理论依据。龙胆苦苷含量测定采用高效液相色谱法,遗传多样性和遗传结构进行研究采用等位酶分析技术。不同产地秦艽的有效成分龙胆苦苷的含量存在一定的差异,对秦艽的6个居群152株通过12个酶位点的分析表明,秦艽具有较低的遗传多样性。每位点平均等位基因数（A）为0．7694,多态位点百分率（P）为16．16,秦艽居群间的遗传分化系数（白t）为0．1247,说明其87．63％的遗传变异存在于居群问。通过对不同地区秦艽药材的有效成分含量和等位酶的分析,为保护野生品种、确保引种栽培秦艽药材的质量提供了科学依据。     

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.