中国苔类孢子形态的研究

通过电镜扫描方法 ,研究了 3个属 9种的中国叶状体苔类植物 :稀枝钱苔 (RicciahuebenerianaLindb .)、宽翅钱苔 (R .hantamensisPerold .)、曲脊钱苔 (R .cavernosaHoffm .)、R .warnstorfiiLimpr.exWarnst.、小孢钱苔 (R .frostiiAust.)、中华钱苔 (R .chinensisHerz .)、东亚花萼苔 (Asterellayoshinagana (Horik .)Horik .)、矮网花萼苔 (A .sanguiniaL .etL .)、背托苔 (Preissiaquadrata) (Scop .)Nees.)。对上述种类的孢子形态特征进行了描述。研究发现 ,上述 3属的孢子形态特征具有明显差异。而且同一属的孢子形态特征也存在差异 ,甚至可以作为种类划分的依据之一。同时采自不同地点的同一种类其孢子形态有时具微小的差别。这可能是由于生态环境差异所造成的     

大叶苔属大陆新发现及棕色原丝薛中国新记录

作者在研究中国西南地区苔藓植物时, 发现了中国大陆一新记录属一大叶苔属(Scaphophyllum), 并首次报导了大叶苔(S. speciosum(Horik.)Inoue)的孢子体. 同时发现了中国藓类植物一新记录种一棕色原丝藓(Tetrodontium browniamum(Dicks.)Sohwaegr.).     

中国苔类新记录种:附基缺萼苔(Gymnomitrion laceratum(Steph.)Horik.)

报道产于西藏的中国苔类植物缺萼苔科缺萼苔1 个新记录种:附基缺萼苔(Gymnomitrion laceratum(Steph.)Horik.)。该种主要特征为植物体具残存但可辨别的腹叶, 有别于该科其它种类。     

中国光萼苔属一新种和一新变种（英文）

描述了光萼苔属的一个新种和一个新变种:卷瓣光萼苔Porella recurve-loba和多齿光萼苔全缘变种P.campylophylla(Lehm.Lindenb.)Trev.var.integra,它们分别采自中国甘肃和云南。提供了上述新分类群的描述和线条图,并且讨论了与它们形态相似种类之间的区别特征。     

凤尾蕨属配子体若干系统学特征新考

通过对凤尾蕨属(Pteris L.)8种,即半边旗(P.semipinnata L.)、傅氏凤尾蕨(P.fauriei Hieron.)、阔叶凤尾蕨(P.esquirolii Christ)、三叉凤尾蕨(P.tripartita Sw.)、蜈蚣草(P.vittata L.)、溪边凤尾蕨(P.excelsa Gaud.)、有刺凤尾蕨(P.setuloso-costulata Hayata)、西南凤尾蕨(P.wallichiana Agardh)孢子的人工培养,观察并总结了该属配子体发育各阶段形态特征,并与以往的观察结果进行比较.最终选取孢子萌发型与配子体发育类型等稳定特征作为判断依据,讨论该属与书带蕨科(Vittariaceae)、中国蕨科(Sinopteridaceae)、铁线蕨科(Adiantaceae)等科的亲缘关系.研究认为蕨类配子体生长点上方边缘细胞分布情况多变,不是稳定的系统学特征.而配子体特定部位边缘细胞的外侧壁形态则具有较高的系统学参考价值.     

茄科马尿泡和天仙子的花器官发生

利用扫描电镜研究了茄科(Solanaceae)天仙子族(Hyoscyameae)中国特有属马尿泡属( Przewalskia Maxim.)马尿泡( Przewalskia tangutica Maxim.)和天仙子属( Hyoscyamus L.)天仙子( Hyoscyamus niger L.)的花器官发生和发育,研究结果表明:马尿泡和天仙子花器官的发生和发育具有以下3个共同特征:1)符合Hofmeister规律, 即新器官的发生首先出现在花顶已经存在的器官之间;2)花冠的发育模式符合茄科植物所具有的"后合瓣"("late sympetaly")现象,即花瓣单独发生但后来又通过它们基部分生组织的融合而连合起来;3)花被五基数且花器官原基发生顺序为向心发育.但是它们的花萼原基具有不同的发生方式.天仙子花萼裂片原基的发生方式为环状发生;马尿泡花萼裂片原基的发生方式为螺旋状发生,但5个花萼裂片原基在都出现后就连成了一个环.马尿泡是介于天仙子属和山莨菪属之间的类群,它比天仙子属原始但较山莨菪属进化.     

西藏合叶苔属新资料

该文在对中国西藏色季拉山苔藓植物野外采集和鉴定的基础上,报道了西藏合叶苔属新资料。结果表明:合叶苔属植物共有13种,其中西藏新记录种2种,即厚边合叶苔(Scapania carinthiaca J.B. Jack)和东亚合叶苔(S. orientalis Steph. ex K. Müller);此外,还有色季拉山新记录种9种,分别为多胞合叶苔(S. apiculata Spruce)、刺边合叶苔(S. ciliata Sande Lac.)、短合叶苔[S. curta (Mart) Dumort.]、长尖合叶苔[S. glaucocephala (Taylor) Austin]、林地合叶苔[S. nemorea (L.) Grolle]、尼泊尔合叶苔(S. nepalensis Nees)、小合叶苔(S. parvifolia Warnst.)、弯瓣合叶苔(S. parvitexta Steph.)、粗疣合叶苔(S. verrucosa Heeg.)。同时,还对其中厚边合叶苔、东亚合叶苔和长尖合叶苔的形态特征和地理分布进行了描述,并提供了主要形态特征的照片。凭证标本存放于中国农业大学标本室(BAU)中。     

苜蓿属和胡卢巴属植物的形态特征及数量分类研究

为研究苜蓿属(Medicago L.)与胡卢巴属(Trigonella L.)间的亲缘关系,寻找两属间的分属依据,解决中间过渡类群的分类归属问题,对苜蓿属与胡卢巴属种类的种皮结构和花粉形态特征进行了观察和测量,并以苜蓿属和胡卢巴属植物的40个形态性状为依据、应用数量分类方法对供试的16个种类进行了聚类分析(UPGMA)和主成分分析(PCA).此外,还根据具有重要分类学意义的形态性状,编写了供试的苜蓿属和胡卢巴属16个种类的分类检索表.观察结果表明,供试的两属植物(11种)的种皮结构基本相同,均由栅栏组织细胞、厚壁细胞和薄壁细胞组成,但胡卢巴属种皮的帽状结构和栅栏组织的厚度均小于苜蓿属.供试的两属植物(9种)花粉形态特征相似,均为椭球形或近球形,赤道面观为椭圆形,极面观为三裂圆形;极轴和赤道轴长分别为22.67～34.67 μm和17.34～31.60 μm;花粉表面纹饰较简单,呈小穴状.种皮结构和花粉特征显示两属的亲缘关系较近,仅种皮结构中的帽状结构差异具有一定的属间分类学意义.聚类分析结果表明,在欧氏距离10.85处,供试的苜蓿属(11种)和胡卢巴属(5种)的16个种类被划分为2组,A组均由胡卢巴属种类组成,B组均由苜蓿属种类组成;在欧氏距离9.32处,B组可被进一步划分为3个亚组,所包含的种类分别为苜蓿属的阔荚亚属(Subgen. Platycarpos D. F. Cui)、镰荚亚属(Subgen. Medicago Tutin)和天蓝苜蓿亚属(Subgen. Lupulina Gressh.)的种类.主成分分析结果表明,前3个主成分的累积贡献率较低,仅57.50%;在前3个主成分中,果实和小叶的长宽比、花萼长和被毛状况、茎和小叶的被毛状况、小叶尖形状、花序长等相关性状的绝对权重值均在0.6以上,具有重要的分类学意义;基于前2个主成分所做的二维散点图中供试的16个种类组成4个表征类群,与聚类分析结果一致.     

桫椤科三种植物配子体发育的研究

用土壤培养桫椤Alsophila spinulosa(Wall.exHook.)R.M.Tryon、中华桫椤A.costularis Baker和白桫椤Sphaeropteris brunoniana(Hook.)R.M.Tryon的孢子,利用光学显微镜对其配子体发育的各个阶段进行了观察,包括孢子形态及其萌发、原丝体发育特点、片状体和生长点的形成及分化、假根特征、精子器和颈卵器的分化及发育,以及原叶体感染真菌后的显微特征。初步讨论了桫椤科不同属(种)间的配子体发育的系统学意义和有性世代的濒危原因。     

东亚分布合叶苔属(苔纲: 合叶苔科) 三种植物的比较和评估

对最近被Potemkin作为同一种处理的合叶苔属Scapania中东亚分布的三种即细齿合叶苔S. parvidens Steph.、弯瓣合叶苔S. parvitexta Steph.和灰绿合叶苔S. glaucoviridis Horik.的模式标本及相关标本进行了比较研究。结果表明, 它们仍应该作为三个独立不同的种来处理。对三个种的模式标本进行了绘图和描述, 并详细讨论了三种之间的区别。     

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.