基因枪转化小麦幼胚的再生培养与转基因植株的获得

以小麦幼胚为受体,用基因枪法对Trx-S反义基因 目的基因 和Bar基因 标记基因 进行了共转化,以轰击后的小麦幼胚为实验材料,对幼胚培养的基本培养基、分化和生根培养基进行了筛选优化.结果表明:4种基本培养基中,L3培养基的成愈率最高,且增殖速度快;MS培养基次之.以L3为基本培养基,分化培养基中添加NAA1mg·L-1和ZT2mg·L-1配比对愈伤组织诱导分化的效果最好,分化率达到50%以上.1/2MS培养基中添加IAA0.8mg·L-1的生根效果好,且移栽成活率高.以优化的培养方案对来自7个小麦品种的幼胚进行转化与再生培养,多数品种的出愈率都达到90%以上,分化率在40%以上,并在5个品种上获得再生植株,经检测证实在4个品种上获得转基因再生植株.     

小麦幼胚培养中的体细胞胚胎发生

小麦品种崇阳红麦和鄂思一号杂种一代幼胚培养具有再生植株的潜力。从一个幼胚经200天左右的连续培养获得530多株再生植株,并从中获得了典型的具有两极性的与愈伤组织块仅局部相连的胚状体。体细胞胚胎发生是小麦幼胚培养的主要途径,但受培养条件的影响,以MS培养基作基本培养基,低浓度2,4-D(0.4mg/1)和水解酪蛋白(1000mg/l)有利于体细胞胚胎发生。     

不同组织培养途径对小麦再生能力的研究

从现在推广的小麦优良品种和有苗头的新品系中选用10个小麦基因型品种进行组织培养,从愈伤组织诱导率、绿苗分化率等方面比较了幼穗培养、花药培养、幼胚培养三种培养方式的培养效果。结果表明,幼胚培养效果最好,基因型间差异小,都能获得足够数量的再生植株。幼穗的培养效果最差,愈伤组织分化生根和绿芽十分容易,但分化成完整植株则较为困难。花药培养在基因型间差异非常明显而且有较多白化苗。此外,本研究还分析了影响小麦再生能力的因素,建立了一套高效、可靠的小麦组培再生系统,为小麦的转基因技术提供优良的受体材料。     

不同小麦品种愈伤组织诱导和再生体系建立

为了筛选适合组织培养的小麦基因型,建立一套有效的小麦诱导再生体系,以24个小麦品种的幼胚为研究材料,选用4种诱导培养基和3种分化培养基,研究了影响小麦组织培养的各种因素。结果表明：①培养基之间存在显著差异,MM2培养基的诱导效果最好,平均诱导率为98．5％,M5B培养基的分化效果最佳,平均分化率为39．8％。②不同品种在诱导愈伤和分化再生上都有显著的基因型差异。③愈伤组织诱导率和分化率之间无显著相关性。     

小麦成熟胚高频植株再生系统的建立

在研究小麦成熟种子不同预处理时间、不同种类和浓度生长调节物质、分化培养基中是否添加CuSO4、不同外植体类型和不同放置方式对小麦成熟胚愈伤组织诱导和分化的基础上,建立了一套高效、可靠、重复性好的小麦成熟胚高频植株再生系统.以小麦成熟种子完整胚作为外植体的诱导频率为100%;除掉胚的原胚芽部位生长出的芽苗后,转分化的分化频率达到42.50%.     

基因枪介导小麦成熟胚遗传转化的影响因素

小麦成熟胚作为转化受体可克服小麦幼胚存在的受季节和幼胚发育阶段限制的缺点。以湖北省小麦品种‘鄂麦12’和模式品种‘Bobwhite’为材料,成熟胚为转化受体,优化基因枪转化法的轰击压力、轰击距离、选择剂等因素,建立以小麦成熟胚为转化受体的高效转化系统。结果表明:小麦成熟胚作为转化受体时,适宜轰击压力和轰击距离组合是900 psi、6 cm;成熟胚对选择剂G418的敏感性强于幼胚,轰击后需要延长恢复时间,选择剂G418的适合浓度为20～40 mg/L。在以上优化条件下小麦成熟胚转化频率达0.3%～0.9%,已初步建立基因枪介导的小麦成熟胚遗传转化系统。     

小麦幼胚培养再生单性雌花的研究

通过45个基因型的小麦(Triticum aestivum L.)幼胚培养,发现有11.1%的基因型从靠近再生芽基部的愈伤组织上分化形成花器官.再生花芽呈裸露的、多子房丛生的、具有茂盛羽毛状柱头而缺乏雄蕊、外稃、内稃和颖片的单性雌花. 组织切片观察发现,其雌蕊起源于再生芽附近的分生组织细胞,并通过次生雌蕊再生的方式形成丛生状,其羽毛状结构的发育先于子房中胚珠的分化. 除正常的单胚珠外,还发现双生胚珠分化.χ2独立性检验结果显示,花芽再生率存在强烈的基因型效应.小麦品种YA-1 表现突出(44.4%),其花芽再生潜力能在不同年份间较好地再现,说明YA-1的花芽再生能力具有相对稳定性.与脱分化培养基的效应相比,YA-1的花芽再生效率主要受继代培养基成分的影响. 其中,6-BA、NAA和加倍无机铁盐的配比较2,4-D和正常浓度无机铁盐的配比更有利于YA-1的幼胚培养再生花芽.同时,外植体实验表明,YA-1的幼穗和成熟胚培养无任何成花反应,而其幼胚外植体具有特异的花芽再生能力.据此认为,YA-1的幼胚培养有助于为小麦花发育机理研究建立理想的实验系统.     

油茶优良无性系子叶体细胞胚植株再生

以油茶优良无性系‘湘林4号’子叶为外植体,采用附加不同种类激素的MS培养基对其进行组织培养实验。研究结果表明:子叶形成胚性愈伤组织的最适合培养基为MS+2.0mg.L-12,4-D+1.0mg.L-1KT;经胚状体诱导产生不定芽分化的最适合培养基为MS+2.5mg.L-16-BA+1.5mg.L-1IAA;油茶优良无性系的生根培养基以MS+7.0mg.L-1NAA最适;通过对植株再生过程中各阶段的组培材料进行RAPD鉴定分析表明,DNA水平上未发现变异,说明通过组织培养建立的油茶优良无性系再生植株同原无性系无明显差别,最终获得的组培苗木能够保持原无性系的优良特性,其遗传是稳定的。     

小麦幼胚培养再生单性雌花的研究

通过45个基因型的小麦（Triticum aestivumL.)幼胚培养,发现有11.1%的基因型从靠近再生芽基部的愈伤组织上分化形成花器官,再生花芽呈裸露的,多子房丛生的,具有藏盛羽毛状柱头而缺乏雄蕊,外稃,内稃和颖片的单性雄花。组织切片观察发现,其雌蕊起源于再生芽附近的分生组织细胞,并通过次生雌蕊再生的方式形成从生状,其羽毛状结构的发育先于子房中胚珠的分化,除正常的单胚珠外,还发现双生胚珠分化。X^2独立性检验结果显示,花芽再生率存在强烈的基因型效应,小麦品种YA-1表现突出（44.4%)。其花芽再生潜力能在不同年份间较好地再现,说明YA-1的花芽再生能力具有相对稳定性,与脱分化培养基的效应相比,YA-1的花芽再生效率主要受继代培养基成分的影响,其中,6-BA,NAA和加倍无机铁盐的配比较2,4,-D和正常浓度无机铁盐的配比更有利于YA-1的幼胚培养再生花芽,同时,外植体实验表明,YA-1的幼穗和成熟胚培养无任何成花反应,而其幼胚外植体具有特异的花芽再生能力。据此认为,YA-1的幼胚培养有助于为小麦花发育机理研究建立理想的实验系统。     

小麦不同生理状态的幼穗和幼胚盾片与诱导分化能力关系的研究

用植物组织培养的方法,研究了冬小麦品种鄂恩1号和品系鄂55072不同生理状态的幼穗和幼胚盾片与诱导分化的关系。结果表明,长度在0.4-2.0cm间的幼穗和直径在0.4-1.5mm间的盾片随生理状态不同,其诱导和分化频率有明显的差异,幼嫩的材料再生频率较高。经SAS统计分析,发现0.5-1.0cm长的幼穗和直径为0.4-1.1mm的盾片是处于诱导分化的最佳生理时期的实验材料,平均每个胚性愈伤组织的植株再生分别达到3.17和5.63株。通过比较幼穗和幼胚盾片的植物组织培养结果,发现幼胚盾片比幼穗愈伤组织出现早,生长快,植株再生绿苗率高,这表明小麦幼胚盾片是较好的植物组织培养的材料。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.     

Time of detection of recessive genes: effects of system of mating and number of examined individuals

Summary Anthers were cultured from two sets of seven lines of hexaploid wheat (Triticum aestivum L.) with different cytoplasms, the euplasmic nucleus donors, Siete Cerros 66 and Penjamo 62, as well as their six alloplasmic lines derived from wild relative species of the genera Triticum and Aegilops. Significant cytoplasmic and nuclear effects but no cytoplasmic-nuclear interaction were found for embryogenic anther response, with the best performance of Penjamo 62 in Ae. kotschyi cytoplasm. Plant regeneration was not affected significantly by the cytoplasmic background of the lines cultured. The possible genetic implications of the observed cytoplasmic and nuclear influences on the in vitro haploid induction of wheat are discussed.