后蕊苣苔属的花粉形态

本文用光学显微镜和扫描电子显微镜系统观察了苦苣苔科后蕊苣苔属的花粉形态,本属花粉粒为近球形,稍长或稍扁,具三拟孔沟,个别种具四拟孔沟的萌发孔类型,外壁表面具网状纹饰,网脊光滑或具小刺。根据网脊宽度。网眼形状以及网纹明显程度而将本属花粉分为三个类群.1.网脊较宽,宽度不均匀,网脊宽度大于网眼直径,包括的植物种类有Opithandra sinohenryi,O.primoloides和O.fargesii等三种;2.网脊较窄,宽度均匀,包括的种类是O.dalzielii,O.obtusidentata,O.dinghushnnensis和O.cinerea等4种;3.网不明显,小刺突出,具这种纹饰的植物只有O.acaulis一种。     

中国沙拐枣属植物花粉形态及其在地层研究中的意义

通过光学显微镜和扫描电镜观察了中国沙拐枣属(Calligonum L.)11种植物的花粉形态。按扫描电镜下的外壁纹饰分类,该属花粉可分为4种类型,即:网纹-穴状具圆形或近圆形网眼、网纹-穴状具多角型网眼、网纹-穿孔和网纹-穿孔或小沟渠。它们的演化趋势是从前面类型依次向后面类型演化。根据花粉内孔的形状,沙拐枣属植物花粉可区别于蓼科其它属植物三孔沟类型花粉。     

山东菊科莴苣亚族植物花粉形态研究

应用光镜和扫描电镜对山东菊科莴苣亚族11属18种、1变种植物的花粉形态进行了观察研究。结果表明:莴苣亚族植物的花粉呈球形,具3~4沟孔,花粉表面具有网状纹饰,粗网眼15~21个,网脊上具1行刺,属于蒲公英(Taraxacum)型,与已报道的莴苣亚族其它属种的花粉形态相一致。通过莴苣亚族属间花粉形态的比较,认为花粉形态在属间分类上意义不大。     

中国蓼科篇蓄属植物花粉形态及其分类意义

利用扫描电镜研究了中国蔚蓄属（Polygonum）13种、1变种、1变型植物的花粉形态。结果表明,中国蔚蓄属植物的花粉粒为长球形或超长球形,具三孔沟,外壁纹饰可分为4种类型：（1）花粉粒表面具细网状纹饰;（2）花粉粒表面具颗粒纹饰;（3）花粉粒表面仅两端具颗粒纹饰,其余部分光滑;（4）花粉粒表面仅沟间区两端肩部光滑,其余部分具颗粒纹饰。根据花粉形态类型,结合该属植物的习性、叶柄基部及花柄上关节的有无、花柱和柱头的数目以及瘦果形态等特征,参照前人的研究处理意见,将中国蔚蓄属植物划分为4个组,即小灌木组section Fruticulosae（Boiss．）F．Z．Liet Y．T．Hou,stat．＆comb．nov．篇蓄组section Polygonum、丝茎蔚蓄组section Pseudomollia Boiss．和铁马鞭组section Plebeia Tzvel．。     

华北地区莴苣属（广义）植物花粉特征的研究

本文研究了华北地区莴苣属（广义）７种植物的花粉形态与微形态特征。结果表明：莴苣属（广义）内这些种具有相同的花粉类型。该属的花粉为球形,３孔沟;极面观为三裂圆形,近六边形;赤道面观为圆形;花粉表面具网状纹饰,同胞１５个,网脊上有许多小穴和规则排列的刺。与邻近属形成明显差异,使该属成为一个自然类群。新属毛鳞菊属ＣｈａｅｔｏｓｅｒｉｓＳｈｉｈｇｅｎ．ｎｏｖ．以其花粉网状纹饰的网脊上具不规则排列的短柱而有别于莴苣属（广义）。花粉的形态特征与微形态特征可为菊科属级水平分类提供重要依据。     

亚洲茜草科粗叶木属及其相关属植物花粉形态研究

利用光学显微镜和扫描电镜研究了茜草科粗叶木属Lasianthus 16种2亚种、1变种及相关的5属5种的花粉形态。粗叶木属的花粉属于广孢型, 单粒。一般中等大小, 绝大多数为圆球形, 少数为近长球形或长球形。花粉形态特征, 特别是在萌发孔和外壁纹饰上表现出多样化。根据孔沟的数目或是否具有内孔, 可以将萌发孔分为(3-)4-(-5)孔沟和3孔。在所观察的这些种中, 萌发孔以3-4孔沟为主要类型, 比例为62.4%。外壁纹饰可分为细网状、粗网状和穴状。有部分种的花粉极面有穴状纹饰, 其余均为网状纹饰。网眼一般椭圆形、近圆形、三角形或者不规则形。少数外壁纹饰网脊上有颗粒状雕纹或模糊的颗粒, 网脊轮廓线呈波浪形, 一般凸出且平滑。大部分种的花粉具有沟膜, 沟膜上具有瘤状突起或小颗粒状, 沟边缘一般较平滑, 或粗糙, 有的种具有沟桥。     

中国东北牻牛儿苗科（Geraniaceae）花粉形态与系统分类学研究

本文对中国东北牛儿苗科Ｇｅｒａｎｉａｃｅａｅ老鹳草属Ｇｅｒａｎｉｕｍ和牛儿苗属Ｅｒｎｄｉｕｍ植物计２属,１４种,２变种及１变型的花粉形态进行了较系统的研究。并对本科花粉形态进行了分类处理,编制了花粉形态科种检索表。结果表明,本科花粉如按萌发孔类型、外壁雕纹式样可以分为二大类：即三孔沟,外壁雕纹瘤状（Ｇｅｒａｎｉｕｍ）三沟,外壁雕纹网状（Ｅｒｏｄｉｕｍ）。在老鹳草属种及种下等级的分类处理中,花粉粒大小、萌发沟长度、外壁覆盖层网眼均匀性、直径大小、网脊上纹饰及外壁雕纹瘤纹突起均匀性、大小及瘤上纹饰都具有较大的分类学意义。花粉形态分类与经典分类对本科分类群的处理意见相吻合。大大丰富了本科分类微形态的证据。     

锦鸡儿属花粉形态及其分类意义

在光学显微镜和扫锚电镜下对锦鸡儿属31种2变种植物花粉形态进行了观察。根据外壁表面纹饰,可分：类型I,表面具小穿孔;类型II, 具网状纹饰。 在类型II中据网眼大小和网脊宽度特征又分为两个亚类型。 根据花粉体积大小,可分4个类型。本属植物花粉形态较为一致,表明是一个自然类群。组、 系的花粉形态特征与一般形态变异不一定相对应,即形态上有明显区别的种类,在花粉形态上未必有很大区别,仅一些种类及矮锦鸡儿系 Ser. Pygmaeae的花粉形态相近。 本属花粉形态在种下等级的变异, 特别是青藏高原分布的种类的变异较为明显,例如 C.bicolor,C. jubata,C. erinacea 与各自的近缘种类。花粉形态为分类处理提供了参考。本属植物花粉形态是从表面具小穿孔向具网状纹饰演化,对应于羽状叶类群向掌状叶类群演化。     

中国荚蒾属植物孢粉学研究

对国产荚蒾属Viburnum Linn．植物花粉的光学显微镜及扫描电镜观察表明：1．花粉特征在组间的分类学意义不大,而在组内的每一种都具各自的花粉特征。2．表面纹饰类型包括(1)外壁具半覆盖层,网状纹饰,网脊光滑;(2)外壁具半覆盖层,网状纹饰,网脊上具瘤状突起;(3)外壁无覆盖层或部分成半覆盖层,具鼓锤状基柱或基柱网,基柱顶端具瘤状突起。3．沟类型包括：(1)沟沿处外壁无覆盖层;(2)沟沿处外壁具半覆盖层,网状纹饰;(3)沟沿处外壁具覆盖层;(4)在一极形成合沟。内孔类型包括(1)看不见明显的孔膜;(2)孔膜半球状,与外壁不连续;(3)孔膜半球状,与外壁相连续;(4)孔膜半椭圆球状,纵长;(5)孔膜半椭圆球状,横架于沟间而类似于桥。文中同时对若干组内分类学问题进行了探讨。     

国产爵床科芦莉花族植物的花粉形态

报道了国产爵床科Acanthaceae芦莉花族Ruellieae芦莉花亚族Ruelliinae 2属7种、假杜鹃亚族Barlerinae 1属3种和马蓝亚族Strobilanthinae 16属34种植物扫描电镜下的花粉形态.芦莉花亚族的地皮消属Pararuellia和喜花草属Eranthemum的花粉均为圆球形,具3孔或3孔沟,外壁为不同的网状结构; 假杜鹃亚族的假杜鹃属Barleria的花粉为长球形,具3孔沟,外壁亦为网状结构;马蓝亚族植物(包含广义的马蓝属Strobilanthes s.l.)花粉形态多样,结构复杂.依据花粉萌发孔和外壁纹饰特征,可将马蓝亚族16属植物和上述两亚族3属植物的花粉形态归纳成3大类型: 1. 具3孔类型.其中又有(1)外壁具网状纹饰者,见于地皮消属; (2)外壁具芽胞状纹饰者,见于黄猄草属Championella; (3)外壁具刺状(棒状)纹饰者,见于南一笼鸡属Paragutzlaffia、叉花草属Diflugossa和假蓝属Pteroptychia.2. 具3孔沟及具3孔沟与假沟类型(肋条带型).其中又有(1)具3孔沟和网状纹饰者,见于喜花草属和假杜鹃属; (2)具刺状(棒状)纹饰者,见于南一笼鸡属、叉花草属和假蓝属; (3)具3孔沟与假沟,外壁纹饰具节隔、肋条带状或网状,网眼纵向排列成行,网眼内有细网纹者,见于耳叶马蓝属Perilepta、马蓝属Pteracanthus(大部分)、金足草属Goldfussia、紫云菜属Strobilanthes(部分)和合页草属Sympagis; (4)具3孔沟与假沟类型,肋条带状,但不具节隔,外壁纹饰网状,网眼不成行或不明显纵向排列,网内无细网纹者,见于尖蕊花属Aechmanthera、板蓝属Baphicacanthus、马蓝属(部分)和糯米香属Semnostachya; (5)具双脊及细网状纹饰者,见于环毛紫云菜Strobilanthes cycla.3. 具(4-)5孔沟及假沟类型(肋条带型),外壁具网状或拟网状纹饰,见于腺背蓝属Adenacanthus.另外兰嵌马蓝属Parachampionella、山一笼鸡属Gutzlaffia和肖笼鸡属Tarphochlamys的花粉有无萌发孔尚不清楚,有待进一步研究.综上所述,芦莉花族植物的花粉形态具有较高的多样性,是重要的分类性状.利用花粉形态特征能较好地区分高级分类群如亚科、族以及亚族,有时也有助于阐明类群之间的相互关系,甚至也能用于区分属、种和阐明其关系.     

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.