鹅掌楸致濒的生态因素研究

鹅掌楸（Liriodendronchinense（Hemsl．）Sarg．）为古老残遗植物,该属植物在第三纪曾广布于北半球。由于第四纪冰川的压力,现存中国鹅掌楸局限星散分布于被称作“避难所”的长江流域以南亚热带山地,其种群大小和结构,受到与其共存的优势树种的竞争压力及人为干扰等多方面因素影响。目前天然分布的鹅掌楸,其种群规模小,在原生境中往往种子饱满率偏低,尤其是位于分布区东部的种群,正处于非适宜的“濒危生境”中。如果物种陷入了因地质历史变化、种间竞争或其他灾难引起的“濒危生境”中,运用迁地保护手段,可有效地保护该物种。     

利用RAPD标记分析北美鹅掌楸与鹅掌楸种间遗传多样性

利用ＲＡＰＤ标记技术对鹅掌楸属（Ｌｉｒｉｏｄｅｎｄｒｏｎ Ｌ．）２个现存种鹅掌楸（Ｌｉｒｉｏｄｅｎｄｒｏｎ ｃｈｉｎｅｎｓｅ （Ｈｅｍｓｌ．）Ｓａｒｇ）和北美鹅掌楸（Ｌｉｒｉｏｄｅｎｄｒｏｎ ｔｕｌｉｐｉｆｅｒａ ｌｉｎｎ．）的遗传多样性进行分析,结果表明：２个种都有较高的遗传多样性,但北美鹅掌楸的遗传多样性水平高于鹅掌楸;鹅掌楸的遗传变异主要来自地理种源内,而北美鹅掌楸的遗传变异主要来自地理种源     

鹅掌楸居群遗传结构及其保护对策

鹅掌楸（Ｌｉｒｉｏｄｅｎｄｒｏｎ ｃｈｉｎｅｎｓｅ（Ｈｅｍｓｌ．）Ｓａｒｇ．）１０个位点上的等位基因电泳结果表明：鹅掌楸种内遗传多样性水平较高,种内遗传变异的２０．６％分布在居群间,７９．４％分布在居群内,东部分布亚区的多样性水平和基因流低于西部,居群间分公程度则高于西部;其遗传我样性随纬度增加而递减,形成南高北低格局。针对我掌楸居群遗传结构的形成原因及现状提出了适宜的保护措施。     

鹅掌楸属引导组织和花粉管生长

鹅掌楸属引导组织和花粉管生长樊汝汶,方炎明,黄金生（南京林业大学,南京２１００３７）１．鹅掌楸属两种植物一中国鹅掌楸（Ｌｉｒｉｏｄｅｎｄｒｏｎｃｈｉｎｅｎｓｅ）和北美鹅掌揪（Ｌ,ｔｕｌｉｐｉ－ｊｅｒａ）的雌蕊引导组织的分布与个体发育是相同的。引导组织...     

中国鹅掌楸与北美鹅掌楸种间杂交的胚胎学研究

中国鹅掌楸与北美鹅掌楸种间杂交的胚胎学研究尹增芳,樊汝汶（南京林业大学,南京２１００３７）应用控制授粉、常规行蜡切片技术,研究了中国鹅掌楸（ＬｉｒｉｏｄｅｎｄｒｏｎＣｈｉｎｅｎｓｅ）×北美鹅掌楸（Ｌｉｒｉｏｄｅｎｄｒｏｎｔｕｌｉｐｉｆｅｒａ）种间杂交...     

七筋姑属种皮形态特征的研究

用扫描电镜对七筋姑属北美全部４个种和东亚七筋姑不同产地的１１个居群进行了种皮微形态特征的观察和研究,结果表明,北美４种中,Ｃｌｉｎｔｏｎｉａ ｕｍｂｅｌｌｕｌａｔａ以其种皮近于平滑、表面分布有大小不等的凹坑而不同于其它各种具条纹状或网穴状的表皮纹饰。北美西部的２个种Ｃ．ｕｎｉｆｌｏｒａ和Ｃ．ａｎｄｒｅｗｓｉａｎａ种皮纹饰相似,关系密切;而北美东部的Ｃ．ｂｏｒｅａｌｉｓ与东亚种Ｃ．ｕｄｅｎｓｉｓ长白     

鹅掌楸配子选择与雄性繁殖适合度

在多父本等量花粉混合授粉的交配实验设计基础上, 利用SSR分子标记对其子代进行父本分析, 研究鹅掌楸的配子选择与雄性繁殖适合度。参试亲本为鹅掌楸2个种的5个单株（鹅掌楸（Liriodendron chinense）2株, 即FY和LS; 北美鹅掌楸（L. tulipifera）3株, 即LYS、MSL和NK）。结果表明： 鹅掌楸的配子选择个体间差异较大。作为母本, NK和LYS倾向于选择异种雄配子, 而MSL和LS则倾向于选择同种雄配子; 在同种雄配子的选择中, NK、LYS和LS倾向于自交, 而MSL则倾向于异交。以北美鹅掌楸为母本时, 北美鹅掌楸与鹅掌楸的雄性繁殖贡献率分别为45.5%和54.5%, 北美鹅掌楸的雄性繁殖适合度为鹅掌楸的0.556倍。以鹅掌楸为母本时, 二者的繁殖贡献率分别为15.6%和84.4%, 北美鹅掌楸的雄性繁殖适合度为鹅掌楸的0.123倍。总体上看, 鹅掌楸的雄性繁殖适合度高于北美鹅掌楸, 鹅掌楸与北美鹅掌楸均表现为自交亲和。     

鹅掌楸属（Liriodendron L．）种质‘优酉’的遗传背景研究

应用光学显微镜和扫描电子显微镜,以鹅掌楸[Liriodendron chinense（Hemsl．）Sarg．]、北美鹅掌楸（L.tutipifera L．）及杂种鹅掌楸（L．chinense×L．tulipifera）为对照,对重庆酉阳鹅掌楸（Liriodendron sp．）种源‘优酉’（‘Youyou’）的外部形态特征、叶表皮微形态结构特征和花粉形态特征进行观察比较,并利用RAPD标记技术对‘优酉’的遗传关系进行了分析。结果表明,鹅掌楸属各树种在外部形态上存在差别,但在叶表皮和花粉形态特征上表现出明显的一致性,‘优酉’的各形态特征与鹅掌楸有较多相似性。RAPD标记分析结果表明,‘优酉’的遗传距离与鹅掌楸和北美鹅掌楸较远,但与鹅掌楸的遗传关系相对较近。推测‘优酉’可能是由较原始的鹅掌楸向较进化的北美鹅掌楸过渡的1个中间类型。‘优酉’生长速度快、观赏价值高,可直接用于园林绿化及林木种植。     

利用EST-SSR分子标记检测鹅掌楸种间渐渗杂交

引进物种常与本土近缘种间发生杂交而导致基因渐渗,进而影响本地种的遗传系统。鹅掌楸(Liriodendron chinense)为我国濒危树种之一,鹅掌楸种间杂交可配性高,近10年来随着北美鹅掌楸(L.tulipifera)的大量引种及杂交鹅掌楸的繁殖推广,鹅掌楸种间发生基因渐渗的可能性大大增加。本文以5个包含鹅掌楸、北美鹅掌楸、杂交鹅掌楸的人工混交林为实验群体,每个群体包含19–130个成年个体及60–117个自然更新小苗或半同胞子代,利用EST-SSR(simple sequence repeat based on expressed sequence tag)分子标记对各子代群体进行亲本分析,探究鹅掌楸种间自然交配方式以检测鹅掌楸种间渐渗杂交;同时,以亲子群体等位基因频率的回归系数作为渐渗系数,定量分析鹅掌楸属种间基因渐渗。结果表明:在研究的5个鹅掌楸混生群体中,均检测到种间渐渗杂交,且渐渗杂交的方向与效应大小在不同群体间有差异。研究还发现,各树种基因渐渗程度与其种群个体数有关,种群个体数越多,其渐渗能力越强。据此,我们还探讨了鹅掌楸种质资源保护策略。     

黑颈鹤(Grus nigricolus)种群生态及濒危等级评估

黑颈鹤的种群总量有５０００～６０００只个体,主要分布在青藏高原和云贵高原,分布区约２２×１０５ｋｍ２,占有面积约５４００ｋｍ２。青藏高原北部和西部为其繁殖区,越冬区主要在雅鲁藏布江河谷中段、喜马拉雅山脉南坡及云贵高原部分区域,青藏高原东部为其迁徙途径之地。越冬时以家族、同种群及混合群（主要与灰鹤Ｇｒｕｓｇｒｕｓ和斑头雁Ａｎｓｅｒｉｎｄｉｃｕｓ）形式集群活动。繁殖期分化为非繁殖群和繁殖对（Ｂｒｅｄｉｎｇｐａｉｒ）两种类型。繁殖对能否成功地占有领域是繁殖成败的关键。笔者认为该物种依ＩＵＣＮ（１９９４）标准应列为易危级（Ｖｕｌｎｅｒａｂｌｅ,ＶＵ）     

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