金针菇品种DUS测试性状的分级与评价

金针菇是著名的食、药两用真菌。以45份金针菇品种为试验材料,对21个性状进行分级与评价,对12个数量性状进行分级,并对其中10个数量性状的相关性和2个数量性状的不同测量部位的影响进行了研究。结果表明:所有性状均适合作为DUS(特异性、一致性和稳定性)测试性状,12个数量性状可分别划分为3–5级;10个数量性状至少与1个其他数量性状显著相关;菌柄由上往下逐渐变粗,不同品种变粗程度略有差异,测量菌柄直径时要求测量菌柄上部1/3处;子实体数量由下往上逐渐减少,不同品种减少程度略有差异,测量子实体数量时要求测量单瓶中长度在基部1/3以上的子实体个数;形态性状的聚类分析结果支持将"菌落:表面色素"、"菌盖:纵切面形状"和"菌盖:表面颜色"作为分组性状。     

六出花属DUS测试性状筛选与评价

以39份六出花品种为试材,对51个候选性状进行观测,比对不同测量方式对花相关数量性状的影响,并同时研究了同品种中外花被片与侧外花被片长度的相关性。结果表明:"花序:花序梗长度"和"花:花梗长度"不满足DUS测试性状要求,最后筛选出43个性状作为DUS测试性状。12个数量性状可分别划分为3~7级;不同观测方式对花相关数量性状具有影响,推荐DUS测试时采用随机观测方式;不同批次的同一品种观测结果部分性状上存在差异;多数品种的中外花被片长度与侧外花被片长度之间呈线性正相关;形态性状的聚类分析结果支持将"花:主色"作为分组性状。     

玉簪属品种DUS测试中数量性状的测定方法探索

利用74份玉簪品种对19个数量性状进行筛选和分级研究,并对不同性状的测量时期和部位进行了探讨。结果表明:叶柄宽度的测试方式采取自然状态下直接测量,花序梗长度测量从基部到第1花苞片着生处的长度,苞片性状全部观测第1花苞片,花相关性状以1~3花中的完全开放花为观测对象;所有候选性状均符合DUS测试指南性状选用的条件,可分为3~9个连续的分级;植株、叶片的观测可改在开花期观测,花序相关性状则在末花期观测。     

无髯鸢尾新品种DUS测试性状筛选

植物新品种特异性、一致性和稳定性(DUS)测试是新品种保护的基础和依据,测试性状的筛选是DUS测试的核心。为制定无髯鸢尾DUS测试指南,初步确定测试性状43个,结合性状间R型聚类分析性状间相关性,去除相关性大、贡献较小的雌蕊长、叶长性状,最终确定操作性强、区别明显的测试性状41个;利用品种间Q型聚类分析确定测试指南的分组性状4个;对性状进行分级及分布分析,保证无髯鸢尾测试指南的可行性,为无髯鸢尾品种测试与授权提供技术支持。     

基于形态性状的菊属与亚菊属植物亲缘关系研究

依据菊花DUS测试指南中性状观测和分级的方法,记录了菊属、亚菊属共31个物种叶片和花序的共计8个定性多态性状,并测量了各物种叶片的14个形态指标,将其转换为7个数量多态性状,分别基于定性多态性状代码和叶片数量多态性状数值利用聚类分析研究其亲缘关系,将两次聚类结果进行比较。结果发现,基于定性多态性状和叶片数量多态性状的聚类结果均可以对菊花近缘属植物进行亲缘关系分析,并与前人利用分子标记的亲缘关系研究及植物学传统分类的研究结果一致,能够较准确地反映种间亲缘关系。而利用菊花DUS测试相关定性多态性状的信息进行亲缘关系研究,具有准确度高、采样简便、工作量小的优点。     

基于DUS测试的水稻标准品种形态性状多样性分析

对水稻DUS测试标准品种进行多样性评价,为DUS测试标准品种的选择和优化提供依据。以DUS测试指南中规定的49个水稻标准品种为材料,根据2008年在杭州田间试验对59个形态性状的调查数据,利用PopGen32软件计算了等位变异数、有效等位变异数和Shannon's多样性信息指数,对标准品种的形态性状多样性进行了评价;并根据其多样性参数采用NTSYS软件对标准品种进行了聚类分析。结果表明,59个形态性状在19份籼稻和30份粳稻品种中分别检测到201和262个等位变异,平均每个性状可以检测到3.4068（籼稻）和4.4407(粳稻)个等位变异,籼、粳稻类群中59个性状的平均Shannon's多样性指数分别为0.8318（0~1.7674）和0.9828（0~1.8547）。聚类分析结果表明,籼、粳稻群体内品种间的形态性状相似系数分别介于0.45~0.81和0.36~0.76,取相似系数0.70为阈值,可将19份籼稻和30份粳稻品种分别分为16和27类。多样性分析表明本研究的49个品种形态性状多样性丰富,具有标准品种性状描述的示例和校正作用;根据聚类分析结果,可将现有标准品种的数量减少至43个。本研究为水稻新品种DUS测试中标准品种的选择和优化提供了参考依据,同时也可供研制其他植物的DUS测试标准借鉴。     

多花黑麦草品种DUS测试数量性状分级分析

对多花黑麦草(Lolium multiflorum Lam.)7个品种进行了不同时期30个数量性状指标的测定,利用数量性状对多花黑麦草性状进行了概率分级的研究,并进行了相关性分析。结果表明,30个数量性状变异范围在7.55%~40.65%之间,变异系数最大的是分蘖数,最小的是千粒重。根据各数量性状的K-S检验及χ2检验,发现仅少部分性状不符合χ2分布;最终将28个数量性状分为5个等级,另外将抽穗期(春化后)和分蘖数分为3个等级。多花黑麦草的30个数量性状之间相关性分析结果表明株高与生长习性、小穗数与小穗密度、上部节间长与节间数呈极显著负相关,花序长与小穗密度呈极显著正相关。研究结果为多花黑麦草品种的鉴定评价、品种选育及数量性状的分级提供了理论依据。     

薏苡新品种特异性、一致性和稳定性测试指南研制

植物新品种满足特异性、一致性和稳定性(合称DUS)是授予品种权的前提条件之一。DUS测试指南是开展DUS测试的技术依据。本文详细介绍了薏苡DUS测试指南的研制过程,包括适用范围、繁殖材料的要求、测试性状的选择、性状表达状态和相应代码的确定、标准品种的筛选、DUS判定标准和技术问卷的设计等。薏苡指南的研制对促进中国薏苡新品种保护,鼓励品种创新及加强品种管理具有重要意义。     

沙生植物沙鞭不同居群形态变异研究

以沙鞭(Psammochloa villosa Bor.)20个自然居群为研究对象,对其株高、花序长度、旗叶长度、旗叶宽度和小穗长度等12个表型性状进行形态变异研究。结果显示,12个性状群体间F值为1.832~8.958,达到显著或极显著水平,表明沙鞭不同居群表型性状存在广泛变异,且变异程度各不相同;主成分分析结果显示,前4个主成分代表了沙鞭形态多样性的82.277%,其中旗叶长度、旗叶宽度、颖片长度、小穗长度等是造成不同居群表型性状差异的主要因素;依据欧式距离对参试居群进行的UPGMA聚类分析结果表明,当遗传距离为20.5时,可以将20个沙鞭野生居群划分为两类,且各表型性状并没有依居群地理分布而聚类。     

重齿当归形态数量性状的分级研究

为明确重齿当归（Angelica biserrata）数量性状的分布规律,对6份种质资源的14个数量性状指标进行测定与分析。结果表明,6份种质资源的8个数量性状存在显著差异,在6个数量性状的差异不显著。14个数量性状的变异系数为6.47%~33.34%,最大的是叶面积,最小的是复叶回数。复叶回数不符合正态分布,叶序数近似于正态分布,其余数量性状均符合正态分布。叶宽、叶长、叶面积、叶周长间呈极显著正相关,相关系数为0.568~0.925,其余数量性状间的相关系数均低于0.560;主成分分析表明,10个数量性状在2个以上主成分中起主要决定作用。概率分级结果表明,去除复叶回数、叶周长、叶面积、叶长、叶序数等5个数量性状,8个数量性状被分为5个连续分布的分级,1个数量性状被分为3个连续分布的分级。     

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.