山东莎草属植物果实形状及果皮微形态研究

利用扫描电镜对山东分布的18种莎草属植物的果实形状及果皮微形态进行了观察研究。结果表明,莎草属植物果实为椭圆状、倒卵状或卵状三棱形,顶端具柱状或锥状短喙;果皮微形态可分为:网-疣复合纹饰、网状纹饰、疣状纹饰和无规则突起纹饰4种类型;果皮微形态类型的划分与基于宏观形态特征的传统分类关联较小,但在该属形态相近的种间存在明显差异,可作为种间划分的依据。果皮微形态证据支持将水莎草属(Juncellus)、砖子苗属(Mariscus)和断节莎属(Torulinium)归入莎草属(Cyperus)的分类观点。     

莎草属果皮微形态特征是及其分类学上的意义

首次报道了在立体显微镜及扫描电子显微镜下对莎草属１４种,２变种植物果皮微形态特征的观察结果。根据纹饰特点的不,可分为三种类型：（１）网－瘤状复合纹饰;（２）网状纹饰;（３）疣状纹饰。莎草属植物在果皮微形态特征上存在的种间差异可为种的划分提供依据,并为探讨该属的系统演化提供有价值的资料。     

中国飘拂草属植物果皮微形态

利用扫描电子显微镜对国产莎草科飘拂草属4组18系42种1变种植物果皮微形态特征进行观察,并作了系统描述。研究表明,飘拂草属植物在纹饰类型,超微结构等方面存在着明显的种间差异,具有分类学意义。根据纹饰及微形态特征的不同,支持将褐鳞飘拂草和知风飘拂草各自作为独立的种。依照果皮纹饰的差异,飘拂草属可分为4种类型(1)瘤(疣)-网状复合纹饰;(2)瘤(疣)状纹饰;(3)网状纹饰;(4)脊-疣状复合纹饰。其中(1)和(3)类型的纹饰根据网脊曲直不同各自又可分为2个亚型。     

国产湖瓜草,球柱草和芙兰草三属果皮微形态特征初探

首次对国产莎草科湖瓜草属、球柱草属和芙兰草属植物的果皮微形态特征进行了扫描电镜的比较观察。结果表明,上述三属果皮纹饰有三种类型：即网状纹饰、疣状纹饰和复合纹饰。其微形态特征存在着明显的种间区别,可为种的划分提供重要依据。研究结果为上述三属植物的分类提供新的佐证,亦为系统演化和亲缘关系的研究提供有价值的资料。     

中国飘拂草属植物果皮微形态特征及其系统学评价

利用扫描电子显微镜对国产莎草科飘拂草属4组42种1变种植物果皮微形态特征进行观察,并作了系统描述,研究表明,飘拂草属植物在纹饰类型,超微结构等方面存在着明显的种间差异,具有分类学意义,根据纹饰及微形态特征的不同,支持将褐鳞飘拂草和知风飘拂草各自作为独立的种,依照果皮纹饰的差异,飘拂草属可分为4种类型：（1）瘤（疣）一纹饰根据网脊曲直不同各自又可分为2个亚型。     

福建荸荠属果皮微形态学研究

本文报道了在立体显微镜和扫描电子显微镜下对福建荸荠属8种、1变种植物果实表皮微形态特征的观察结果。根据果皮纹饰的不同,可分为两种类型:网状纹饰、拟网状纹饰;荸荠属植物果实表皮微形态特征具有丰富的多样性,表型可塑性小,不同类群之间具有明显的种间差异。观察结果表明:荸荠属果实表皮微形态特征是该属分类与系统研究中不可忽视的性状。     

北京7种鬼针草属植物果实微形态特征及其系统学意义

采用扫描电镜方法对北京地区鬼针草属植物7个种的果实微形态特征进行了观察、比较。结果表明:(1)7种鬼针草属植物瘦果的果体形状、表面棱的数目、芒刺(冠毛)数目及其上倒刺数目和生长位置等特征可以作为鉴定各种的重要形态学依据。(2)根据果皮在扫描电镜下表面纹饰类型及表皮细胞形状等特征,可将7种鬼针草分为两类:一类果皮表面为典型的网纹纹饰,表皮细胞呈不规则多边形,细胞界限明显;另一类果皮表面为条状网纹或纵条纹纹饰,表皮细胞呈长圆形或长条形,细胞界限不明显。由于7个种的果皮表面纹饰有着明显的差异和各自的特点,并与根据叶形、地理分布及分子等证据得出的系统亲缘关系结果基本相符,表明这一特征可能具有一定的系统学意义。     

变豆菜属11种植物的叶表皮微形态特征研究

为探讨叶表皮微形态特征在变豆菜属植物中的系统及分类学意义,我们利用扫描电镜对变豆菜属11个种(13个居群)的叶表皮微形态特征进行了研究。结果表明,11种变豆菜属植物叶表皮微形态特征较稳定,上表皮细胞轮廓大多不清晰,初级蜡质纹饰均存在条状纹饰,表皮上均粘附着颗粒物;下表皮均存在气孔,气孔周围存在均匀分布的纹饰,气孔外拱盖表面大多有颗粒状纹饰,并且其二级纹饰类型、气孔周围纹饰、气孔外拱盖内缘纹饰等叶表皮微形态特征上存在一定差异。上述研究结果可为探讨变豆菜属类群界定及种间关系提供重要依据。     

中国水鳖科（Hydrcharitaceae）植物的果皮微形态特征

应用扫描电镜地国产水鳖科６属植物的果皮微形态特征进行了初步的观察。结果表明水鳖科各属植物在果皮面纹饰及表皮细胞形态,径向壁和横向凸出与否等特征上存在差异,可以作为属间分类的依据之一．从果皮微形态特征来看,水鳖属和海菜花属差异很大,支持将它们分别作为不同的族处理的观点,而水筛属和苦草属则较为近缘。果皮微形态下的观察结果表明水鳖科和泽泻科植物在果皮表现细胞形态,径向壁明显凸出等方面十分相似,因而支持了     

中国水鳖科（Hydrocharitaceae）植物的果皮微形态特征

应用扫描电镜对国产水鳖科6属植物的果皮微形态特征进行了初步的观察。结果表明水鳖科各属植物在果皮表面纹饰及表皮细胞形态,径向壁和横向壁凸出与否等特征上存在差异,可以作为属间分类的依据之一。从果皮微形态特征来看,水鳖属和海菜花属差异很大,支持将它们分别作为不同的族处理的观点,而水筛属和苦草属则较为近缘。果皮微形态下的观察结果表明水鳖科和泽泻科植物在果皮表面细胞形态,径向壁明显凸出等方面十分相似,因而支持了水鳖科与泽泻目近缘的观点。     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

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.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细