新疆东天山地区宽刺蔷薇居群表型多样性分析

对新疆东天山地区6个宽刺蔷薇（Rosa platyacantha）居群进行叶片、花序、果实、种子等11个表型性状的遗传多样性分析,结果表明：宽刺蔷薇各表型性状无论在居群间还是在居群内均表现出显著或极显著差异,存在丰富的表型多样性。6个居群11个性状的平均表型分化系数为27.50%,表明居群内多样性较居群间多样性更为丰富。各表型性状平均变异系数为16.51%,离散程度相对较低。对表型性状进行的变异系数多重比较和主成分分析均显示,果实相关性状的变异是造成宽刺蔷薇表型变异的主要来源。性状相关性分析进一步发现,生殖生长与前期的营养生长并无明显相关关系。聚类分析结果表明,6个宽刺蔷薇居群的表型性状并没有严格依地理距离聚类,而是受到遗传因素与环境条件特别是海拔因子的共同影响。     

垂珠花自然居群表型性状及遗传多样性分析

为探索垂珠花自然居群间表型差异的内在因素,该研究用14个表型性状和微卫星分子标记法对6个垂珠花自然居群进行遗传多样性分析。结果表明:(1)14个表型性状在居群间和居群内皆存在极显著差异;居群间平均表型分化系数(V_(st))为22.64%,垂珠花自然居群内的表型变异大于居群间的表型变异,说明居群内变异是垂珠花居群的主要变异来源。(2)4对微卫星引物在87个个体上共检测到43个等位基因,平均每条引物10.63个,平均多态位点百分率(P)为100%;平均观察杂合度(H_o)和平均期望杂合度(H_e)分别为0.659和0.811,Shannon多样性指数(I)平均达1.894;居群内遗传多样性(H_s)高达0.811,居群间遗传多样性(D_(st))仅为0.110,居群间遗传分化系数(F_(st))为0.118,说明11.8%的遗传变异来自于居群间,88.2%的遗传变异来自于居群内,与表型变异研究所得结论大体相一致。表型性状和微卫星分子标记结果均表明垂珠花自然居群存在丰富的遗传变异,较高的基因流(Nm=2.050)使得垂珠花居群间的遗传变异小于居群内的遗传变异。     

云南滇龙胆居群表型多样性及其与环境关系研究

为揭示滇龙胆天然居群表型变异程度和变异规律,以云南省5个区域天然分布的20个野生居群400个单株20个表型性状指标为调查研究对象,并用变异系数、Shannon-Weiner多样性指数和巢式方差分析对滇龙胆居群间和居群内的表型变异进行分析,用相关性分析对滇龙胆表型性状与地理气象因子间的变异格局进行分析,用类平均聚类法对20个滇龙胆居群进行分类.结果表明:5个区域的滇龙胆以楚雄地区变异最大,变异系数为39.8%,变异最小的是昆明地区,为31.4%;不同居群的20个表型性状变异程度差异明显,变异系数在14.4%～91.8%之间,平均为40.4%,20个居群的平均变异为26.8%～37.0%;滇龙胆地理居群的表型分化较高,20个性状居群间的分化系数平均为73.14%,变化范围为36.03%～91.94%,居群间变异高于居群内;滇龙胆20个表型性状的总的多样性指数平均为2.547,5个不同分布区域多样性指数存在差异,最大为楚雄(1.271 4),最小为玉溪(1.266 7);表型性状变异受经度和降雨量影响较大,与纬度、海拔和温度相关性不显著;通过UPGMA聚类,滇龙胆被分成3个组,性状的表型特征并没有依地理距离而聚类....     

云南含笑天然居群的表型多样性分析

为揭示云南含笑天然居群表型变异程度和变异规律,以云南昆明地区天然分布的云南含笑为研究对象,调查了6个居群180个单株的14个表型性状,采用巢式方差分析、变异系数、相关分析、Shannon-Weaver多样性指数分析和聚类分析等方法,分析了居群间和居群内表型多样性.结果表明:(1)云南含笑表型性状在居群间和居群内存在极其丰富的多样性,14个表型性状平均表型分化系数(24.38％)小于居群内变异(75.62％),居群内变异是表型变异的主要来源;14个表型性状的变异系数(CV)在16.20％～60.11％之间,表明云南含笑居群内表型性状离散程度较高.(2)对云南含笑各居群的Shannon-Weaver指数分析表明,云南含笑各居群具有丰富的多样性,总体表型多样性指数为1.772.(3)利用居群间欧氏距离进行的UPGMA聚类分析结果表明,云南含笑6个天然居群可以聚为3类,而且表型性状并没有严格依地理距离而聚类.     

浙江省野生蜡梅花部形态变异及其与环境因子的相关性

以浙江省蜡梅自然分布区的5个居群为研究对象,采用巢式方差分析、主成分分析、相关分析、聚类分析等多种分析方法,探究蜡梅花部的形态变异及其与环境因子相关性以及居群间和居群内的表型多样性。结果表明:蜡梅花部性状中除雄蕊长度、雌蕊数、雌蕊长度、内被片数以外,其他12个性状在居群间均有极显著差异。胚珠数的平均变异系数最大,花冠内径的平均变异系数最小,各性状的平均变异系数为15.03%(10.81%—23.38%)。五尖山的表型多样性最丰富,碧东山居群最小,种群间平均表型分化系数为44.38%(1.57%—89.62%),种群内变异大于种群间变异,种群内变异是花部变异的主要来源。主成分分析显示花冠直径、花冠内径、花筒深度和中被片长对种群变异起主要贡献作用。花部多数性状间存在显著或极显著的相关关系,生态因子中花部性状与土壤酸度相关性最大,土壤中花部性状与大量元素相关性最大,微量元素次之,中量元素最小。通过UPGMA聚类分析可以将5个种群分成两组。浙江省野生蜡梅花部形态存在丰富的变异和多样性,花部部分性状与土壤中钙、铁、铜含量和海拔有显著或极显著相关关系。     

披碱草属野生居群表型多样性及其与环境关系研究

以来自8省区38个披碱草属野生居群的22个表型性状为调查对象,利用变异系数及多样性指数法对性状内和性状间及种间的表型变异进行分析,并对表型性状与地理气象因子间的关系进行相关性分析,用平均聚类法对38个居群进行分类,以揭示不同来源披碱草属种质资源表型多样性。结果显示:(1)营养器官性状中旗叶至穗基部长变异系数最高(44.695%),穗部性状中的每穗小穗数变异系数最高(77.005%)。(2)披碱草、麦宾草、圆柱披碱草与老芒麦这4个种间总体平均多样性指数为0.920～1.560,披碱草最高,麦宾草次之,圆柱披碱草最低。(3)表型性状变异受海拔、经度及年均温的影响较大。(4)UPGMA聚类结果将所有材料分成4组,披碱草属植物性状的表型特征没有严格按地理距离而聚类。研究表明,披碱草属植物野生种质材料具有丰富的表型多样性,表型性状与环境之间关系密切,采集过程中应尽量保持居群的完整性,最大程度地保护中国披碱草属牧草的遗传多样性。     

茶条槭自然种群种子和果实表型多样性研究

为探析茶条槭(Acer ginnala)种子和果实表型差异程度及变异规律,该研究采用巢式方差分析、主成分分析、聚类分析等方法,对茶条槭主要分布区内7个种群种子和果实的12个表型性状进行比较研究,分析茶条槭种群间和种群内的表型多样性以及与地理生态因子的关系。结果表明:除种子长/宽(SLW)外,其它11个表型性状在茶条槭种群间和种群内均具有显著差异;各性状平均变异系数(CV)为13.90%,变异幅度为8.14%～32.08%;种群间翅果性状的平均变异系数(15.63%)高于种子性状的平均变异系数(8.71%),表明种子性状的稳定性高于果实性状。主成份分析中,果实形态特征对茶条槭种群表型的贡献率大于种子贡献率。种群间表型分化系数为35.47%,说明种群内变异(64.53%)大于种群间变异(35.47%),暗示变异主要来源于种群内变异。茶条槭种子和果实表型性状受地理生态因子影响较小,主要受自身遗传因素的影响。基于种群间欧式距离的聚类分析将茶条槭7个种群分为2大支,没有严格按照地理距离而聚类,表明茶条槭种群表型性状变异的不连续性。茶条槭不同种群种子和果实具有较高的表型多样性,与其分布范围和生物学特性有关。     

蒙古冰草表型数量性状的变异与生境间的相关性

采用多因变量线性模型方差、变异系数、主成分分析及UPGMA聚类分析的数量统计方法,对来自内蒙古中东部地区的6个天然居群和2个栽培品种(品系)的花序10个数量性状进行了分析。结果表明,蒙古冰草在花序各部的表型性状上存在有居群内及居群间的差异,同时,天然居群的变异程度大于栽培品种,而且居群间的分化与生态环境因子有着密切的相关。     

云南泸定百合遗传多样性的表型与ISSR分析

用表型变异分析并结合ISSR分子标记对云南境内10个泸定百合(Lilium sargenttiae)居群进行遗传多样性分析。结果显示:(1)云南10个泸定百合居群的7个表型性状的居群间F值在3.26～19.1之间,表型的居群间差异均达到显著或极显著水平;平均表型分化系数为71.22%,居群间变异(59.92%)大于居群内变异(23.42%),说明居群间表型变异是泸定百合居群变异的主要来源。(2)13个ISSR引物共检测到248个多态位点,物种水平上多态位点率98.80%,Nei’s多样性指数和Shannon多样性指数分别为0.265 5和0.413 1;居群内基因多样度(Hs)为0.175 7,居群间基因分化系数(Gst)0.336 7,Mantel检验显示泸定百合居群在地理距离和遗传距离间具有显著相关性(r=0.804 4,P=0.009 9)。研究表明,云南泸定百合的居群间表型和分子水平均具有较高的遗传多样性,居群间的遗传分化较大,并且分化趋势具有明显的地域性。因此,可选择迁地种植对泸定百合进行有效保护。     

新疆准噶尔山楂不同居群的遗传多样性

为了揭示新疆准噶尔山楂(Crataegus songorica)不同居群的遗传多样性,为其合理保护与利用提供科学依据,采用表型性状变异分析和SSR分子标记相结合的方法,对新疆霍城大西沟准噶尔山楂的5个不同居群的92个个体进行遗传多样性分析。结果表明:(1)33个表型性状的变异系数在2.96–71.32%之间,表型性状之间存在着丰富的变异。居群间的平均表型分化系数为13.90%,而居群内的平均表型分化系数为86.10%,表明新疆准噶尔山楂居群内的变异是其表型变异的主要来源。(2)43对SSR引物共检测到739个位点,物种水平上多态性位点比率为90.53%,Nei’s多样性指数和Shannon多样性指数(I)分别为0.2377和0.3712,居群内基因多样度(H_s)为0.1635,总居群基因多样度(H_t)为0.2023,居群间遗传分化系数(G_(st))为0.1916,基因流(N_m)为2.1116。新疆准噶尔山楂总的遗传多样性水平较高,居群间遗传分化较小。UPGMA聚类结果显示5个居群形成2个亚类,不同居群所处的生境的不同是引起居群间差异的主要原因。研究表明,新疆准噶尔山楂不同居群在表型和分子水平均具有较高的遗传多样性,居群内的遗传分化较大,并且分化趋势具有地域性,因此可以选择就地保护。     

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.