南方红豆杉种子综合处理过程中内源激素的动态变化

为揭示南方红豆杉种子内源激素与休眠的关系,采用酶联免疫吸附法(ELISA)测定了经过层积处理的种皮和胚乳的脱落酸(ABA)、赤霉素(GA3 )、吲哚乙酸(IAA)、玉米素核苷(ZR)4种内源激素含量的变化情况.结果表明:种子胚乳中内源ABA的含量随着层积时间的延长而逐渐下降,GA含量增加,IAA和ZR的含量先增加后降低...     

外源NO对瓶插期间的月季切花中内源激素含量的影响

以硝普钠（SNP）为一氧化氮供体,研究NO及其清除剂2-苯基-4,4,5,5-四甲基咪唑啉-1-羟-3-氧（PTIO）影响月季瓶插期间的生理指标和内源激素含量的结果表明：0.1mmol.L-1SNP释放的NO抑制月季切花瓶插期间花瓣中内源乙烯释放速率和ABA含量的升高,延缓IAA含量的下降,并保持组织中相对较低的ZR和GA水平。PTIO则可促进花瓣中的乙烯、ABA、ZR和GA含量的升高和IAA含量的下降。     

萘乙酸与多效唑对茉莉成花及新梢内源激素含量的影响

在茉莉开花前期分别使用不同浓度NAA与PP333均匀喷施于植株茎、叶片等生长部位,对其新梢与花蕾生长及其4种内源激素--生长素(IAA)、赤霉素(GA)、脱落酸(ABA)、玉米素核苷(ZR)的含量变化进行分析.结果表明:(1)NAA处理使茉莉新梢徒长,成花比对照推迟2～4 d;PP333处理的茉莉新梢矮化,而成花比对照提早2～4 d.(2)NAA处理后,茉莉新梢中IAA与ABA含量处理初期较高,后快速下降,后期稳定在较高水平;GA含量稍低于对照,ZR含量降低并稍低于对照.PP333处理后,茉莉新梢中IAA与ABA含量初期较高,而后缓慢下降;GA含量与对照一样快速上升;ZR含量在初期含量较高,后缓慢下降,但较对照稳定在较高水平.(3)PP333处理的茉莉植株新梢中ABA/IAA、GA/IAA、ZR/IAA比值在处理后迅速上升,特别是GA/IAA、ZR/IAA比值明显高于对照,而相应NAA处理的3个比值与对照无明显差异.可见,经NAA与PP333处理能明显调节茉莉新梢及花蕾生长进程,保持较高水平的内源激素GA、ZR、GA/IAA、ZR/IAA比值在茉莉新梢及花蕾生长过程中起关键作用.     

光皮树花芽分化过程中内源激素含量变化的研究

以4年生光皮树嫁接苗为材料,采用酶联免疫吸附法（ELISA）测定同龄开花光皮树与不开花光皮树叶内4种内源激素生长素（IAA）、赤霉素（GA3）、玉米核苷素（ZR）、脱落酸（ABA）含量的动态变化,研究成花过程中叶片内源激素含量的变化与成花的关系。研究结果表明：在芽分化时期开花光皮树和未开花光皮树叶内4种内源激素含量动态变化存在显著差异。有花芽分化的光皮树保持相对较低和稳定IAA、GA3含量,ABA含量高且变化幅度较大,ZR含量相对较低,但随着花的形成含量逐渐升高;而在相同的生长季内,无花光皮树IAA、GA3含量先升高后降低,ABA含量先逐渐升高,然后下降,而ZR含量呈现出先逐渐升高然后降低,再升高再下降的变化趋势。因此,4种内源激素含量的动态变化影响光皮树的成花过程。     

分析拟南芥叶片在激素促进的衰老中内源激素变化来解析抑制磷脂酶Dα1延缓激素促进衰老的机制

采后衰老进程在很大程度上受到内源和外源激素的影响。抑制拟南芥中磷脂酶Dα1（phospholipaseDtxl,PLDod）的表达后,使得外源脱落酸（abscisic acid,ABA）和乙烯加速的离体叶片衰老过程在一定程度上得到了缓解。然而,内源激素在这个过程中的作用尚不清楚。本研究对比分析了野生型和PLDα1缺失型两种基因型拟南芥叶片在3种不同人工老化过程中（离体诱导的、外源ABA和乙烯促进的衰老过程）,内源ABA,茉莉酸甲酯（methyl jasmonate,MeJA）、吲哚乙酸（indole-3-acetic acid,IAA）、玉米素核苷（zeatin riboside,ZR）和赤霉素（gibberellic acid,GA,）的含量变化。这5种激素对3种不同衰老处理方式的响应模式表明了人工老化过程存在着两个不同阶段,并且在衰老早期每种激素的变化模式相同。PLDα1功能缺失使得激素加速的衰老过程得以延缓,这与内源ABA、MeJA、ZR和IAA的含量变化有关。而与GA、的含量变化无关。同时,ZR和IAA的变化模式也说明了这两种激素的变化可能是缺失PLDα1延缓激素加速的衰老过程这一事件的原因而非结果。     

低温条件下不同抗寒性薰衣草内源激素的变化

为揭示薰衣草内源激素与抗寒能力的关系,以抗寒性相对较强的狭叶薰衣草和抗寒性较弱的宽叶薰衣草为试验材料,在田间自然条件下,于越冬前不同降温时期分别对叶片和根系取样,采用酶联免疫吸附法（ELISA）测定和分析了内源激素ABA、GA3、IAA和ZR的含量变化。结果表明,两种薰衣草的叶片和根系中的ABA、IAA和ZR的含量随气温的降低均表现为先升高后降低的趋势,但GA3表现为持续下降的趋势。抗寒性强的狭叶薰衣草叶片和根系中的ABA、IAA和ZR含量均高于抗寒性弱的宽叶薰衣草,而GA3小于宽叶薰衣草。对薰衣草越冬起重要作用的内源激素是ABA。     

大果白刺种子内源激素含量研究

目的：探究大果白刺种子萌发过程中内源激素的变化。方法：通过HPLC测定低温层积后大果白刺种子内源激素含量的变化。结果：大果白刺种子GA₃含量显著提高，而ABA、IAA、ZR和ETH含量均显著下降。GA₃/ABA值显著提升，IAA/ABA和ZR/ABA值呈现下降趋势。结论：GA₃含量和GA₃/ABA值较高，ABA、IAA、ZR、ETH含量和IAA/ABA、ZR/ABA值较低，证明各种内源激素含量及其比值是制约其种子休眠的重要因素。     

棉花花芽分化时期茎尖内源激素的变化

实验结果表明,从子叶展平后到肉眼可花芽（现蕾）,所测几种激素（ABA、IAA、GA3、iPA、ZR）的含量均表现出明显的动态变化,而且在花芽分化临界期表现出最显著的变化（出现高峰或出现低峰）。推测所测几种激素均与花芽分化有密切关系。其中ABA、GA3和CTK（iPA、ZR）在花芽分化临界期时,其含量变化均呈现出一个高峰;而IAA则在花芽分化临界期时出现一个低峰。经比较分析得知,随着花芽分化的进行,ABA/IAA、GA3／IAA、CTK／IAA均表现一个较明显的变化规律。即从子叶展平时起,其比值开始上升,到花芽开始分化时达到一个峰值,之后逐渐下降,并维持在一个较稳定的水平。显然,ABA／IAA、GA3／IAA、CTK／IAA在棉花的花芽分化过程中起着重要的调控作用。由此推测,增加植物体内的ABA、GA3、CTK的含量或降低IAA的含量,都可以促进棉花的花芽分化;反之则抑制棉花的花芽分化。     

分析拟南芥叶片在激素促进的衰老中内源激素变化来解析抑制磷脂酶Dα1延缓激素促进衰老的机制

采后衰老进程在很大程度上受到内源和外源激素的影响。抑制拟南芥中磷脂酶Dα1 (phospholipase Dα1, PLDα1)的表达后,使得外源脱落酸（abscisic acid,ABA）和乙烯加速的离体叶片衰老过程在一定程度上得到了缓解。然而,内源激素在这个过程中的作用尚不清楚。本研究对比分析了野生型和PLDα1缺失型两种基因型拟南芥叶片在3种不同人工老化过程中（离体诱导的、外源ABA和乙烯促进的衰老过程）,内源ABA,茉莉酸甲酯（methyl jasmonate,MeJA）、 吲哚乙酸（indole 3 acetic acid,IAA）、玉米素核苷（zeatin riboside,ZR）和赤霉素（gibberellic acid,GA3）的含量变化。这5种激素对3种不同衰老处理方式的响应模式表明了人工老化过程存在着两个不同阶段,并且在衰老早期每种激素的变化模式相同。PLDα1功能缺失使得激素加速的衰老过程得以延缓,这与内源ABA、MeJA、ZR和IAA的含量变化有关,而与GA3的含量变化无关。同时,ZR和IAA的变化模式也说明了这两种激素的变化可能是缺失PLDα1延缓激素加速的衰老过程这一事件的原因而非结果。     

水杨酸对两个品种百合鳞茎膨大的作用及其与内源激素含量的关系

百合品种‘精粹’的鳞茎周径和鲜重随着叶面喷施水杨酸（SA）的浓度的增加而增加;品种‘普瑞头’鳞茎周径和鲜重也随着叶面喷施SA的浓度的变化而变化,其中以0．5mmol·L^-1SA的效应最明显。叶面喷施SA的百合鳞茎中ABA和GA3含量下降,IAA和ZR含量上升,鳞茎中（IAA＋GA3）／ABA、IAA／GA3比值均比未喷施SA的高,而IAA／ZR、GA3／ZR比值则比未喷施SA的低。显示鳞茎膨大与内源激素的含量相关。     

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