中国蓼属叉分蓼组植物花粉形态的研究

采用光学显微镜和扫描电镜对中国蓼属叉分蓼组20种3变种的花粉形态进行了观察和研究。结果表明其花粉形态大多数为近球形至近长球形,少数为扁球形或长球形;花粉大小为20.4～44.0µm×17.0～34.0µm：从萌发孔看,有3沟、3 孔沟、多沟、散沟;外壁纹饰为微刺—穴状、刺状、粗网状、皱块状。据此,该组花粉可划分为5种类型,即叉分蓼型(Aconogonon-type)、钟花蓼型(Campanulatum-type)、大连线冰岛蓼型(Forrestii-type)、西伯利亚蓼(Sibiricum-type)及多穗蓼型(Polystachyum-type),编制了这些花粉类型检索表。叉分蓼型花粉的主要特征是具3沟,外壁纹饰为微刺-穴状,此种类型的植物有14种2变种。钟花蓼型花粉的主要特征是具6散沟,外壁纹饰为微刺-穴状,此种类型的植物有钟花蓼和绒毛钟花蓼。西伯利亚蓼型花粉的主要特征是具3孔沟,外壁纹饰为皱块状,此种类型的植物有西伯利亚蓼。多穗蓼型花粉的主要特征是具6(~8)多沟,外壁纹饰为粗网状,此种类型的植物有松林蓼及多穗蓼。大连线冰岛蓼型花粉的主要特征是具散沟,外壁纹饰为显著的长刺状,此种类型的植物有大铜钱叶蓼及铜钱叶蓼,结果表明叉分蓼组的花粉形态具有重要的分类学意义,研究结果支持将叉分蓼组上升为属的等级,也支持Knorringia的属的地位,大铜钱叶蓼和铜钱叶蓼应移入Koenigia属中,而松林蓼和多穗蓼仍保留在蓼属中。     

分子证据支持蓝药蓼和大铜钱叶蓼归入冰岛蓼属

蓝药蓼Polygonum cyanandrum Diels和大铜钱叶蓼P.forrestiiDiels是否应归于冰岛蓼属Koenigia至今未得到很好的解决。本文利用叶绿体DNA的atp B-rbc L序列来评价这两个物种的亲缘关系和属的归属。对这两个物种以及相关代表种的atp B-rbcL序列分析发现,该片段的长度有较大的变异。从753bp到902bp;存在丰富的系统发育变异位点。系统发育分析表明：蓝药蓼和大铜钱叶蓼与冰岛蓼丘islandica聚为支持率较高的分支。而蓼属Polygonum代表种和其他属的代表种组成另外的分支,表明这两个种应置于冰岛蓼属。这一结果与花粉和染色体证据相吻合。根据这些证据以及形态学特征,还对冰岛蓼属与蓼属的范围与界定进行了讨论。     

基于trnL-F序列推测冰岛蓼属的系统发育

冰岛蓼属的界定一直存在争议,本实验以塔黄为外类群,采用最大简约法对冰岛蓼属及其近缘类群的trnL-F序列进行了系统发育分析,结果表明:(1) 冰岛蓼(Koenigia islandica)和大铜钱叶蓼(Polygonum forrestii)为姊妹群,自展分析的支持率为100%,因此,大铜钱叶蓼应归于冰岛蓼属;(2) 冰岛蓼和分叉蓼组植物聚在一起,自展支持率为99%,说明它们之间有很近的亲缘关系.     

中国蓼属植物花粉形态的研究

本文用光学显微镜和扫描电镜对国产44种2变种蓼属植物的花粉形态进行了观察。除了前人报道的31种外,其中15种为首次报道。本属花粉形态多类型,有球形、近球形、近扁球形、近长球形及长球形;从萌发孔来看,有三沟型、三孔沟型、散沟型及散孔形：外壁纹饰有颗粒-穿孔、微刺-穿孔、微刺-凹穴、细网状、皱块状及粗网状。根据这些特征将花粉划分为10种类型,其中西伯利亚蓼型(Sibir-icum-type)为本文首次提出。文中对本属的分类问题进行了探讨,不支持Steward(1930)将本属划分为8个组的意见,而认为应将本属划分为11个组。     

中国蓼属分叉蓼组和冰岛蓼属植物叶下表皮微形态研究

采用光学显微镜对中国蓼属分叉蓼组(Polygonum section Aconogonon)和冰岛蓼属(Koenigia)的21种植物的叶下表皮微形态进行了观察研究。结果表明,其叶下表皮微形态特征可分为三种类型：（1）气孔器类型为无规则型,表皮细胞多边形,垂周壁为波状;（2）气孔器类型为无规则型兼有非典型不等型,表皮细胞为多边形或不规则形,垂周壁为平直弓形或波状;（3）气孔器类型为不等细胞型,表皮细胞多边形,垂周壁为平直弓形。分叉蓼组（西伯利亚蓼除外）植物的叶表皮气孔器类型具有高度一致性,说明该组是一个自然类群。本文研究结果不支持将大铜钱叶蓼(Polygonum forrestii Diels)、铜钱叶蓼(P. nummularifolium Meissner)划归于冰岛蓼属的处理意见;支持将西伯利亚蓼(P. sibiricum Laxm.)独立成属,即西伯利亚蓼属(Knorringia Tzvel.)的观点;同时也支持仍将多穗蓼(P. polystachyum Wall.ex Meissner)和松林蓼(P. pinetorum Hemsl.)归在分叉蓼组的处理意见。     

蓼科花粉外壁超微结构的研究

用扫描电镜和透射电镜对蓼科6属15种的花粉壁构造的特点进行了观察和研究。结果表明：(1)外壁纹饰有如下几种：颗粒-穿孔,微刺-穿孔,微刺-穿孔-光滑,颗粒-穿孔-光滑,细网状,粗网状,皱块状,鼓锤状;(2)外壁结构分化成两个明显的层次,即外壁外层以及外壁内层。其外壁外层由覆盖层、柱状层和基层组成。然而,由于每一部分发育状况的不同而导致外壁结构有各种变化,如无覆盖层或无外壁内层。     

安徽蓼科植物花粉形态的研究

用光学显微镜对安徽省蓼属３８种３变种,酸模属３种,荞麦属１种,金线草属２种,大黄属１种,竹节蓼属１种的花粉形态进行了观察。除了前人报道的３７种外,其中１２种为首次报道。６属的花粉形态多类型,有球型,近球形,近长球形、扁球形、长球形;从萌发孔来看,有３－沟,３（－４）－孔沟,１２－散沟、３０－散沟、９－散孔沟、２０－３０－散孔;外壁纹饰有细网状,粗网状,皱块状,颗粒－穿孔、穿孔、微刺－穿孔－光滑、颗     

对翼蓼(蓼科)属级位置的重新探讨

通过对翼蓼Pteroxygonum giraldii Damm. &; Diels及相关属(蓼属Polygonum、何首乌属Fallopia、虎杖属Reynoutria、荞麦属Fagopyrum和金线草属Antenoron)的形态观察、果实解剖学观察、花被片脉序观察、花粉形态、核型分析, 以及ITS序列的分析确定了翼蓼和荞麦F. esculentum Moench较远的亲缘关系。其中我们发现翼蓼果实基部有三个角状物明显不同于其他属果实的形态特征。翼蓼外果皮明显加厚, 并有零星散布的波状内腔, 而荞麦的外果皮很薄, 细胞不等径, 中果皮极厚。以上证据证明了翼蓼与荞麦属亲缘关系较远。在观察荞麦属和翼蓼的花被片脉络时发现了两种不同的脉序类型, 符合将荞麦属分为两个组的划分。翼蓼花被片脉序为三出状, 支持将翼蓼归为Persicarieae族。对翼蓼及荞麦属植物的花粉进行比较后, 发现荞麦属植物的花粉网孔有明显的内凹穿孔而翼蓼却没有, 结果表明二者亲缘关系较远。通过对nrDNA ITS区域序列分析得出翼蓼及相关属为一个单系类群, 含有两个稳定的分支: 第一个分支由蓼属(萹蓄组sect. Avicularia)、何首乌属、虎杖属的植物组成, 第二个分支由蓼属(刺蓼组sect. Echinocaulon、蓼组sect. Polygonum、分叉蓼组sect. Aconogonon、拳参组sect. Bistorta、翼蓼和荞麦属植物组成。同时第二个分支又分成了两个亚分支, 蓼属(刺蓼组、蓼组、分叉蓼组、拳参组)和翼蓼属Pteroxygonum植物属于第一个亚支而荞麦属植物属于第二个亚支。结果支持翼蓼不属于荞麦属的范畴。实验结果显示翼蓼是个单型属, 属于Persicarieae族。     

中国酸模属植物花粉形态研究

利用光学显微镜、扫描电镜对１５种,透射电镜对２种国产酸模属植物的花粉进行观察与研究。本属花粉为球形或近球形,大小为１５～４０×１８～４０μｍ。具３孔沟、４斜孔沟、散孔沟、散沟等;沟或外沟狭长,几达两极,内陷或不内陷,内孔圆形、稍横长或纵长;表面具皱波状纹饰;外壁厚１．０～３．５μｍ,外层明显厚于内层。在透射电镜下,花粉外壁分３层：覆盖层最厚,具穴状或穿孔,颗粒状或刺状纹饰,内面均匀;柱状层明显,厚,小柱为钝圆锥体或圆柱状,基层和内层不分,最薄,但在萌发孔处明显增厚。根据花粉形态,本属花粉可以分成７个组,它们是：小酸模组、滨海酸模组、酸模组、土大黄组、荒地酸模组、巴天酸模组和钝叶酸模组。对萌发孔分布规律的研究,基本支持Ｗｏｄｅｈｏｕｓｅ（１９３１）的观点,同时据花粉萌发孔演化的规律,认为本属花粉可能是蓼科花粉由少数萌发孔向多数萌发孔演化的过渡类型。     

青藏高原东缘的锈菌资料VII.

本文报告了蓼科植物上的柄锈菌属二新种和一中国新记录种,它们是抱茎蓼Polygonum amplexicaule D. Don上的巴克利柄锈菌Puccinia barclayi S. Ahmad、牛皮消蓼Fallopia cynanchoides (Hemsl.) Harald.上的宽乳柄锈菌Puccinia latimamma J. Y. Zhuang& S. X. Wei sp. nov.以及蓝药蓼Polygonum cyanandrum Diels和细茎蓼Polygonumfilicaule Wall. ex Meisn.上的蓝药蓼柄锈菌Puccinia polygoni-cyanandri J. Y. Zhuang & S.X. Wei sp. nov..新种有拉丁文描述.每个种都作了讨论并附有线条图.标本保藏在中国科学院菌物标本馆(HMAS).     

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.