蒺藜苜蓿MtROP5启动子与GUS基因融合构建的稳定转化及其表达特性

本文以3～4周大小的蒺藜苜蓿R108．1的叶片为外植体,通过根癌农杆菌介导的遗传转化系统将MtROP5启动子与GUS报告基因的融合构建导入蒺藜苜蓿中,该转化系统经体胚发生产生转化的再生植株。利用PCR扩增对转化植株进行初步鉴定,并通过GUS4J6学染色法分析MtROP5启动子的组织表达特性。结果表~）]MtROP5启动子主要在蒺藜苜蓿根、花、果荚、叶片和种子中表达。     

农杆菌介导的苜蓿次级体细胞胚的遗传转化

采用农杆菌菌株GV3101感染子叶期苜蓿体细胞胚来研究苜蓿次级体细胞胚的遗传转化方法。农杆菌菌株GV3101双相载体pCAMBIA2301,此双相载体具有gus报告基因和nptⅡ抗卡那霉素筛选基因。感染的子叶期苜蓿体细胞在75 mg/L卡那霉素筛选压下,经过一系列诱导培养,最终获得转基因植株。然后,通过GUS组织化学定位分析来检测转基因植株不同器官中的GUS表达,并进一步通过PCR和Southern杂交确定转基因的稳定整合和转化率。结果表明转基因植株不同器官均有GUS表达,整合的nptⅡ基因的拷贝数是1~4,获得的转基因植株的转化率是65.82%。     

根癌农杆菌介导的苜蓿悬浮胚性愈伤遗传转化体系的建立与优化

苜蓿基因型是限制遗传转化的关键因素之一。本实验通过对7种苜蓿胚性愈伤组织诱导,筛选出一份具有高频再生潜力的基因型公农-1号,并以该基因型为转化平台探索和建立了一套高效的苜蓿遗传转化系统。分析了影响农杆菌共培养转化苜蓿悬浮胚性愈伤的因素,优化了悬浮培养条件,建立的超声波辅助农杆菌介导苜蓿胚性愈伤的遗传转化系统为：以下胚轴诱导的愈伤组织经悬浮培养得到的胚性愈伤为转化材料,乙酰丁香酮为100 μmol·L^-1、超声波处理时间8 s、卡那霉素筛选浓度30 mg·L^-1、共培养4 d,接种于选择培养基上进行筛选和再生。最终,获得了大量的转基因植株,分子检测证实目的基因-角碱蓬液泡膜型Na⁺/H⁺逆向转运蛋白基因已经整合到苜蓿基因组中。     

苜蓿红豆草属间体细胞杂种的分子生物学鉴定

通过原生质体融合和培养获得苜蓿红豆草属间体细胞杂种植株。采用一种简便方法从杂种组织再生植株叶片、红豆草羟脯氨酸抗性系再生植株叶片和苜蓿根癌农杆菌702转化系愈伤组织提取DNA用于RAPD和Southern杂交分析。随机引物扩增结果显示两种亲本的RAPD多态具有明显差异。在所用20种随机引物中,6种产生较多的DNA片段。杂种组织具有两种亲本特有的DNA片段,但倾向于排除红豆草亲本的染色体,表明该杂种为非对称杂种,两种亲本染色体之间可能发生了重组。由于红豆草DNA的介入,杂种组织表现出较强的分化能力。分别利用RAPD扩增得到的OPA141000bp红豆草羟脯氨酸抗性系特异产物和OPA141600bp苜蓿根癌农杆菌702转化系特异产物为探针进行Southern分子杂交,证明杂种组织同时具有这两种DNA片段的同源序列。     

AtNDPK2 基因转化敖汉苜蓿及其耐盐性分析

植物核苷二磷酸激酶(NDPKs),属于蛋白激酶家族,参与植物的多种生理生化过程,在植物响应非生物胁迫过程中发挥重要作用。NDPK2基因转化紫花苜蓿,对提高紫花苜蓿的耐逆性具有重要意义。试验以"敖汉"苜蓿下胚轴的再生系统为基础,通过农杆菌介导法将SWPA2驱动的AtNDPK2基因转入紫花苜蓿下胚轴,获得抗性植株。通过PCR初步检测证明该基因已经整合到"敖汉"苜蓿的基因组,阳性植株转化率为23.3%。不同浓度NaCl胁迫测定转基因植株的SOD、POD活性及质膜相对电导率、MDA含量,结果发现在0.4%~1.0%NaCl胁迫下转基因植株的SOD、POD酶活性显著高于对照,相对电导率、MDA含量显著的低于对照,进一步说明AtNDPK2基因的转入增强了"敖汉"苜蓿的耐盐性。     

布鲁氏菌rOmp31_(48-74)-BLS重组载体的构建与苜蓿的转化

将布鲁氏菌rOmp3148-74-BLS基因转入紫花苜蓿中苜一号,最终获得转基因苜蓿。本试验利用不依赖于连接反应的克隆(Ligation-Independent Cloning,LIC)方法将布鲁氏菌rOmp3148-74-BLS基因克隆到植物表达载体pJG045上,并利用三亲本杂交的方法转化农杆菌AGL0。最后通过农杆菌介导法将该基因转化紫花苜蓿中苜一号。经PCR鉴定,筛选出转基因苜蓿植株。本试验为今后布鲁氏菌转基因植物疫苗的研发奠定了理论和实验基础。     

沙冬青脱水素基因提高转基因紫花苜蓿的耐旱性

为鉴定转基因紫花苜蓿的耐旱能力,本研究以转基因紫花苜蓿T0代植株为材料,通过干旱胁迫,从转基因植株的表型、生理指标和分子水平等层面检测转基因植株的抗旱特性,试验表明,干旱胁迫后转基因苜蓿和对照的茎、叶片全部干枯,而复水后转基因苜蓿大部分恢复生长,对照几乎全部死亡。干旱胁迫后苜蓿叶片的Pro和MDA含量均随处理时间延长而逐渐增加,转基因植株叶片的Pro含量高于对照,而其MDA含量低于对照植株,且二者均达到了显著差异;转基因苜蓿的离体叶片失水率也明显低于对照。在20%PEG胁迫下,植株体内ProDH和P5CS基因的相对表达量都是先升后降,转基因植株和对照中ProDH和P5CS基因的表达量显著增加,且二者在转基因植株与对照间存在显著差异。这表明,在干旱胁迫条件下,由于AmDHN基因在紫花苜蓿中的过量表达,可能引起植株体内脯氨酸的大量积累,并进一步诱导脯氨酸合成相关基因的表达,最终引起植株抗旱性的提高,因此,推测转基因苜蓿的耐旱性比对照强。     

烟草MnSOD基因在保定苜蓿中的转化

通过农杆菌介导的转基因方法 ,将烟草MnSOD基因的cDNA序列导入保定苜蓿中 ,成功地诱导了转基因植株的再生。转基因植株生长和发育良好 ,NPTⅡ基因和MnSOD基因的PCR检测和Southern杂交表明MnSOD基因已经导入到保定苜蓿的再生植株中 ,MnSOD活性检测表明部分转基因植株的MnSOD活性显著高于对照植株     

冻融法转化苜蓿中华根瘤菌

对于苜蓿中华根瘤菌转化方法的研究仅限于三亲杂交法和电激转化,本实验首次将冻融法用于转化苜蓿中华根瘤菌。将携带CUS片段并且含有壮观霉素抗性的质粒用冻融法转移至野生型苜蓿中华根瘤菌菌株,得到的抗性克隆用GUS引物进行PCR扩增鉴定。经过计算,冻融法的转化率为2．2×10^5／μg。与传统方法比较,冻融法操作简单,转化过程快速,转化率较高,所需时间较短,转化成本低,是适合用于苜蓿中华根瘤菌的转化方法。     

天蓝苜蓿原生质体培养再生植株

苜蓿属（Ｍｅｄｉｃａｇｏ）植物多为优质牧草,是进行原生质体培养研究较多的一个属。至今已有１０余种苜蓿属植物进行过原生质体培养的研究,多数获得了再生植株［１～６］。天蓝苜蓿是一种优质牧草、绿肥和药用植物。关于它的体外培养已有一些报道［５,７,８］,但原生质体培养尚未能再生植株。本文以悬浮系为材料进行了原生质体的分离与培养,并经胚状体发生和器官发生两种途径获得了再生植株。１　材料和方法天蓝苜蓿（ＭｅｄｉｃａｇｏｌｕｐｕｌｉｎａＬ．）种子采集于吉林省西部草原。干种子用浓硫酸浸泡３ｍｉｎ,升汞灭菌５ｍｉ…     

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.     

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     

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.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV