瑞香属植物生物活性研究进展

瑞香属植物分布广泛,在我国有35种。其中一些种类自古即供药用、观赏和作造纸原料。近几十年来,人们已从瑞香属植物中发现了60多种具不同作用的生物活性物质。药理学和毒理学研究表明,这些活性物质中,有的抗HIV、白血病、血栓形成和动脉粥样硬化,有的可抑制铜绿假单孢菌、细菌和疟原虫感染,有的可用于临床引产,还有的具杀虫和抑菌作用。说明这是一个大有开发前途的植物类群。     

瑞香属和荛花属的数量分类研究

瑞香属和荛花属为瑞香科瑞香亚科的落叶或常绿灌木,中国西南部是瑞香属和荛花属的重要分化中心。全世界共有瑞香属95种、荛花属70种,中国分布有瑞香属52种、荛花属49种。瑞香属和荛花属的分类学研究一直存在不同程度的分歧。花盘形状和果实类型在传统分类中一直是区分瑞香属和荛花属的典型特征,而花盘形态和果实类型在2个属中存在交叉和过渡,部分植物分类学家根据这些特征将两个属进行过不同程度的归并。该研究采用数量分类法对瑞香属77种(变种)和荛花属62种(变种)植物,选取32个形态学性状进行聚类分析和主成分分析。结果表明:聚类分析和主成分分析均显示两属均未形成单系类群。在主成分分析中,前3个主成分分析的贡献值为35.56%,传统分类中用来区分两属的花盘形状、叶序及果实类型等特征对前3个主成分贡献相对较小,因此,传统分类学中对这两个属进行区分的性状并没有典型的分类学意义。同时,聚类图和主成分分析得到的散点图均不能将这两个属区分开来。数量分类研究结果显示两属植物存在明显的交叉,支持瑞香属和荛花属不是两个独立自然类群的观点。     

广西禾本科植物二新记录属

该文报道了广西禾本科(Poaceae)植物二新记录属,即菵草属( Beckmannia Host)和草沙蚕属( Tripogon Roem. et Schult.)。菵草属有2种及1变种,分布较广,我国有1种1变种,广西首次记录到该属的菵草[ Beckmannia syzigachne (Steud.) Fern.]。草沙蚕属约有30种,多分布于亚洲和非洲,我国有11种,广西首次记录到该属的线形草沙蚕( Tripogon filiformis Nees ex Steud.)。同时,还提供了2个新记录属、种的形态描述与照片。     

瑞香属和荛花属(瑞香科)植物叶表皮特征及其分类学意义

选取瑞香科瑞香属(Daphne)植物56种(变种)、荛花属(Wikstroemia)植物45种(变种),及12种外类群植物,进行叶表皮微形态解剖学研究。结果表明,瑞香属和荛花属植物叶表皮细胞大多为多边形和不规则形,垂周壁大多为平直、弯曲和浅波状,大小为30~40μm×10~20μm,部分具毛。气孔呈随机分布,大小为20~36μm×17~25μm,宽椭圆形或窄椭圆形,气孔密度为100~250 S/mm2,气孔主要类型为无规则型(anomocytic)。瑞香属与荛花属的叶表皮性状整体具有一致性,两属间没有典型区别特征,很多性状在两个属中呈交叉分布,不反映瑞香属和荛花属分别是自然(单系)类群。毛管花属(Eriosolena)植物特有的乳突(papillae)特征在瑞香属和荛花属植物中均不存在,不支持将其并入瑞香属的分类处理。通过气孔器类型比较分析认为,瑞香属和荛花属与瑞香亚科中的其他属,如鼠皮树属(Rhamnoneuron)、毛管花属、假狼毒属(Stelleropsis)、Daphnopsis、结香属(Edgeworthia)相比具衍生性状,是衍生类群。     

广西豆科植物新记录属——镰瓣豆属

该文报道了中国广西豆科(Fabaceae)植物新分布记录属,即镰瓣豆属[Dysolobium (Benth.) Prain],同时描述了该属的分类学特征,并提供了镰瓣豆[D. grande (Benth.) Prain]的引证标本、地理信息和图片。     

中国鹿角兰属(兰科)植物新资料

报道了中国兰科(Orchidaceae)鹿角兰属(Pomatocalpa)一新记录种——纹瓣鹿角兰［P. tonkinense (Gagnep.) Seidenf.］,凭证标本保存于广西植物研究所标本馆(IBK)。纹瓣鹿角兰的花序疏生多数花,萼片、花瓣均具2条紫色条纹,中萼片及花瓣远长于侧萼片,与中国原记录的2种鹿角属植物容易区分。该研究提供了新记录种的形态描述、中国鹿角兰属植物图版及分种检索表。     

中国苦苣苔科一新记录属——四轮苣苔属

该文报道了中国苦苣苔科(Gesneriaceae)一新记录属——四轮苣苔属(Tetraphyllum Griff. ex C. B. Clarke)。该新记录属,即四轮苣苔属仅有3种,其中密花四轮苣苔[T. confertiflorum(Drake)B. L. Burtt]在我国首次记录。该研究提供了该属的形态描述和分种区别特征,并提供了该种的详细形态描述及彩色照片。凭证标本馆藏于广西植物研究所标本馆(IBK)和上海辰山植物标本馆(CSH)。     

黄金柏属——中国柏科一新记录属

报道了中国广西北部石灰岩地区柏科一新记录属——黄金柏属,提供了分布于我国广西的越南黄金柏的详细形态描述及照片。该种原记录仅分布于越南北部石灰岩地区,目前在我国仅见于广西北部的木论国家级自然保护区。     

广西兰科植物二新记录属

该文报道了广西兰科(Orchidaceae) 2个新记录属,即鹿角兰属(Pomatocalpa Breda)和独花兰属(Changnienia S. S. Chien)。鹿角兰属植物共有13种,中国分布有2种,广西首次记录到该属的台湾鹿角兰[Pomatocalpa undulatum (Lindley) J. J. Smith subsp. acuminatum (Rolfe) S. WatthanaS. W. Chung];独花兰属为单种属,仅独花兰(Changnienia amoena S. S. Chien) 1种,该种为中国特有种,广西首次记录。该文还提供了新记录属和种的形态描述和图片。     

不同来源凹叶瑞香中香豆素类成分的TLC分析

本文利用TLC法对不同产地凹叶瑞香不同部位所含香豆素类成分进行了综合比较分析。结果表明,不同产地的同种凹叶瑞香的主要化学成分是基本一致的,而与其它种间差别较大。这一结果为瑞香属的合理分类及开发利用提供了科学资料。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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.