从“湖北光敏感核不育水稻”的未受精子房和花药培养出单倍体植株

采用10种诱导培养基,培养湖北光敏感核不育水稻农垦58品种的未受精子房和花药。共培养未受精子房2790个,获得胚囊愈伤组织17块,最高诱导频率达3.33%,其中2块分化出绿苗。培养花药16740个,获得花药愈伤组织15块,最高诱导频率为0.92%,其中3块分化出苗,2丛白苗,1株绿苗。胚囊植株和花粉植株经根尖染色体检查为单倍体,2n=x=12。实验证明,液体培养、2,4-D0.2-0.5 mg/1、低温预处理对诱导胚囊愈伤组织及花粉愈伤组织的形成具良好效果。     

温敏核不育小麦可育花药和败育花药发育观察

对温敏核不育小麦百农不育系（Bainong sterility,BNS）的可育和不育花药结构进行对比观察。在减数分裂期、小孢子早期和小孢子晚期,可育花药与不育花药的结构相同。小孢子分裂形成二胞花粉后,可育花粉中随着大液泡的分解,细胞质内含物增加,其中出现一些颗粒状物质。不育花药中,小孢子也可分裂形成二胞花粉,但营养细胞的大液泡不分解,细胞质也不增加,最终花粉中的细胞质消失,花粉败育。该种温敏核不育小麦的花粉败育时间发生在二胞花粉早期,可能和其大液泡没有适时分解有关。花粉败育时间的确定为进一步深入研究该种雄性不育小麦的败育机制打下了基础。     

光周期诱导光敏感核不育水稻花药蛋白变化的研究

采用双向电脉技术对不同光周期条件下,光敏感核不育水稻（农垦５８ｓ）的可育与不育花药蛋白的变化进行分析,发现花粉发育的不同阶段中,不育花药具有四个特异蛋白ｐＩ６．２／ｂＭＷ７０ＫＤ,ｐＩ６．２／ＭＷ６８ＫＤ,ｐＩ６．２／ＭＷ３８ＫＤ和ｐＩ７．４／ＭＷ３７ＫＤ．对游离组蛋白的分析表明．长日照诱导的不育花药中游离组蛋白的相对百分率均明显低于短日照下的可育花药．据此推测长日照诱导不百花药蛋白质组成和代谢变化．不育花药中游离组蛋白含量低,可能受ＤＮＡ合成数量少的影响．     

小麦遗传型与生理型雄性不育花药蛋白质双向电泳分析

为了研究小麦雄性不育蛋白表达机制, 以具有异质同核的3个亲本: 即遗传型不育系ms(S)-西农1376、对应的保持系(A)-西农1376和生理型(化学杀雄剂SQ-1诱导)雄性不育系ms(A)-西农1376为材料, 利用IEF/SDS-PAGE凝胶电泳技术, 对发育到单核后期的花药全蛋白特异性进行了比较分析, 得到320~350个清晰的蛋白点。结果表明: 遗传型和SQ-1诱导的生理型不育系蛋白质图谱与正常保持系在蛋白质(多肽)表达量上存在一定的差异, 同时发现有几种蛋白质的表达有明显的特异性, 两个不育材料2D胶上共有几个明显的特异蛋白点, 而在保持系中未发现; 两个不育材料又分别具有自己的特异蛋白表达, 不育机理不同; 比较分析可知, 不育系中某些蛋白的表达受到了抑制, 并开启了与花药败育有关的特定蛋白的表达, 可能使物质能量代谢受阻,导致雄性不育的发生。     

春小麦花培育种的遗传研究初报

春小麦是我省主要粮食作物,1987年将花药培养的一系列技术应用于育种,先后通过花药培养出一系列品系,已有品系参加省级品种区域性试验。 本文对花培育种的遗传研究表明:对植株诱导率的影响,即不同生态型、基因型F_1花药受不同年份,同时受不同生态区的不同地点,影响出愈率,分化率;供体植株基因型,以花培品系为亲本组合,其平均诱导率均高于不含花培品系的组合,说明小麦再生能力是花培育种的一个特点。不同世代供体基因型,几年来,我们彩用F_1代供体杂种,是提高诱导率和缩短育种年限的有效措施。花粉植株的遗传与变异是育种工作所注目的。     

基因型对春麦花粉植株诱导率影响的研究

花药培养中,不同基因型供体对于花粉植株的影响很大.几年来的研究结果表明,用花培品系做亲本配置杂交组合;不同世代的基因型,尤其是F_1代花药供体植株;亲本基因型在提高花粉愈伤组织出愈率、花粉绿苗分化及花粉绿苗率方面均有明显的效果.     

Ta1小麦轮选群体高分子量谷蛋白亚基组成分析

利用Ta1小麦 Ms2 创建改良小麦面包品质的优质群体,采用SDS-PAGE法对其2次互交轮回群体C2的HMW-GS组成进行了分析.结果表明:在供试的193个样品中各HMW-GS及其组成模式的频率不尽相同,Glu-A1、Glu-B1和Glu-D1位点上产生频率最高的亚基分别是1、14+15和2+12,各为54.40%、35.75%和60.10%,优质亚基5+10的频率为17.6%; null、14+15、2+12 模式产生频率最高,为13.47%,并有 14+15,5+10 的优质亚基聚合体出现,占5.2%;该群体也产生了亲本不具有的13、16、22亚基及19种新的HMW-GS组成模式.说明利用Ta1小麦轮回选择技术是创造新亚基类型的一个有效途径.     

太谷核不育小麦花药内游离脯氨酸和总氨基酸含量的变化及其与育性的关系

本文对显性单基因控制的太谷核不育小麦不同发育阶段的可育株和不育株的花药及雌蕊内游离肺氨酸和游离总氨基酸的含量进行了分析。结果表明:(1)在小孢子母细胞减数分裂期,不同育性花药之间游离脯氨酸的含量无明显差异,且含量较低。(2)在小孢子单核初期,可育花药内游离脯氨酸的含量显著高于不育花药,是不育花药的7倍,比减数分裂期增加20倍,高达其干重的1.65％,占其游离总氨基酸的50％。(3)在雌蕊中,游离脯氨酸的含量远远低于花药,不同育性植株之间差异不很明显。(4)关于游离总氨基酸的含量,在花药中减数分裂期,不同育性植株之间无明显差异;在小孢子单核初期,可育株高于不育株。在雌蕊中,相应于小孢子单核初期时,可育株稍高于不育株,受精后迅速趋于一致,但整个变化幅度不大。     

温敏不育系A3314在中国不同生态地点的育性表现

利用作者参与发明的ZL00105488．0专利方法选育的小麦温度敏感不育系A3314在中国元谋、杨陵、石家庄、互助、依安、贵阳、武威7个不同纬度地点种植的自交结实率,结合各点光温条件的分析表明：A3314在黄淮冬麦区、云贵冬麦区、西北春麦区、东北春麦区各点,按当地小麦生产正季播种均表现稳定雄性不育;而在黄淮和云贵冬麦区春播(夏播)则自交结实,适宜条件下自交结实率可达60％以上。说明该温敏不育系的雄性育性受温度的制约,而与日长无明显相关。根据A3314的育性表现,推测它在中国大部分小麦产区均可安全用于杂交小麦制种。     

Nuclear-pore-complex dynamics and transport in higher eukaryotes

Summary The nuclear-pore complex controls the passage of macromolecules to and from the nucleus. It is a complex structure spanning the double-membrane nuclear envelope, consisting of many proteins and structural components. Structurally it consists of a series of stacked rings and associated filaments and a central cylinder which appears to contain the transport channel. Much of the pore complex appears to be dynamic, altering conformationally during transport. We review what is known about pore complex structure and dynamics and attempt to relate this to recent new information on transport pathways and the interactions of transport factors with each other and with components of the nuclear-pore complex.     

Nucleosome Interactions and Stability in an Ordered Nucleosome Array Model System

Although it is well established that the majority of eukaryotic DNA is sequestered as nucleosomes, the higher-order structure resulting from nucleosome interactions as well as the dynamics of nucleosome stability are not as well understood. To characterize the structural and functional contribution of individual nucleosomal sites, we have developed a chromatin model system containing up to four nucleosomes, where the array composition, saturation, and length can be varied via the ordered ligation of distinct mononucleosomes. Using this system we find that the ligated tetranucleosomal arrays undergo intra-array compaction. However, this compaction is less extensive than for longer arrays and is histone H4 tail-independent, suggesting that well ordered stretches of four or fewer nucleosomes do not fully compact to the 30-nm fiber. Like longer arrays, the tetranucleosomal arrays exhibit cooperative self-association to form species composed of many copies of the array. This propensity for self-association decreases when the fraction of nucleosomes lacking H4 tails is systematically increased. However, even tetranucleosomal arrays with only two octamers possessing H4 tails recapitulate most of the inter-array self-association. Varying array length shows that systems as short as dinucleosomes demonstrate significant self-association, confirming that relatively few determinants are required for inter-array interactions and suggesting that in vivo multiple interactions of short runs of nucleosomes might contribute to complex fiber-fiber interactions. Additionally, we find that the stability of nucleosomes toward octamer loss increases with array length and saturation, suggesting that in vivo stretches of ordered, saturated nucleosomes could serve to protect these regions from histone ejection.     

提高春小麦花粉植株诱导率的研究

本文研究了影响春小麦花粉植株诱导率的几种主要因素。供试材料为1990年温室种植的杂种F_1代,试验结果表明,诱导培养基中附加细胞分裂素BA或BA与KT相结合能显著提高愈伤组织分化率;0.17M的葡萄糖加0.17M的蔗糖比用0.26M的蔗糖愈伤组织诱导率高60％以上;愈伤组织在18～25℃比在23～25℃下培养绿苗率显著提高;接种前2～3℃预处理幼穗72小时对提高出愈率和绿苗分化率有明显效果。     

SESAME: A least-squares approach to the evaluation of protein structures computed from NMR data

Summary A method is proposed for defining a probability distribution on an ensemble of protein conformations from a 2D NOE spectrum, while at the same time back-calculating the experimental spectrum from the ensemble. This enables one to assess the relative quality and significance of the conformations, and to test the consistency of the ensemble as a whole with the experimental spectrum. The method eliminates the need to integrate the cross-peak intensities and is surprisingly insensitive to random noise in the spectrum. In this communication, these advantages are demonstrated by applying the method to simulated data, for which the correct result is already known.Abbreviations NOE nuclear Overhauser effect - BPTI basic pancreatic trypsin inhibitor - rmsd root-mean-square deviation     

不同细胞质的普通小麦\"中国春\"(Triticum aestivum var.Chinese Spring)与小偃麦杂交F1代的育性与减数分裂行为的研究

15个不同细胞质“中国春”小麦与八倍体小偃麦杂交 ,杂种F1减数分裂的染色体行为表明 :普通小麦与天蓝偃麦草的F或E组染色体之间存在着部分同源关系 ;D2 型细胞质促进部分同源染色体配对、但却抑制同源染色体配对 ;Sv 型细胞质对同源染色体或部分同源染色体的配对均有抑制作用 ;G型细胞质促进同源染色体配对。1 5个不同细胞质“中国春”小麦与六倍体小偃麦杂交 ,F1结实率很低 ,减数分裂中期的染色体行为混乱 ,单价体过多 ,或许意味着在天蓝偃麦草 (Elytrigiain termedium)与长穗偃麦草 (E .elongatum)的E组染色体之间存在着很大差别。随着回交代数的增加 ,选出G型、D2 型、Mt 型、Mu 型等细胞质雄性不育的八倍体小偃麦品系 ,其中D2 型细胞质八倍体小偃麦具有光周期敏感性雄性不育的特征 ;G型细胞质“远中 3”育性正常 ,表明八倍体小偃麦“远中 3”的E组染色体中存在G型胞质的育性恢复基因。     

Nucleosome Interaction Surface of Linker Histone H1c Is Distinct from That of H10

The fully organized structure of the eukaryotic nucleosome remains unsolved, in part due to limited information regarding the binding site of the H1 or linker histone. The central globular domain of H1 is believed to interact with the nucleosome core at or near the dyad and to bind at least two strands of DNA. We utilized site-directed mutagenesis and in vivo photobleaching to identify residues that contribute to the binding of the globular domain of the somatic H1 subtype H1c to the nucleosome. As was previously observed for the H1⁰ subtype, the binding residues for H1c are clustered on the surface of one face of the domain. Despite considerable structural conservation between the globular domains of these two subtypes, the locations of the binding sites identified for H1c are distinct from those of H1⁰. We suggest that the globular domains of these two linker histone subtypes will bind to the nucleosome with distinct orientations that may contribute to higher order chromatin structure heterogeneity or to differences in dynamic interactions with other DNA or chromatin-binding proteins.     

小麦花药培养中小孢子DNA合成的放射自显影研究

用放射自显影术研究小麦花药培养中小孢子的雄核发育,发现培养24小时后3H－胸腺嘧啶核苷掺入单核晚期小孢子,2．5天后营养细胞核中有3H－胸腺嘧啶核苷掺入,由A和B途径形成多细胞花粉的过程中,超始几次孢子体分裂,细胞的DNA合成是同步进行的。在多细胞花粉形成时逐渐变为不同步,生殖核的DNA合成不活跃,偶而能被标记上,个别合成DNA的生殖细胞形成类胚柄结构,当培养基中蔗糖浓度低（3％）时,培养早期小孢子内核的DNA合成正常进行,3H－胸腺嘧啶核苷比高糖浓度（9％）更易惨入小孢子,但经1－2次分裂后,核不再分裂,细胞壁不形成,所以3％的糖浓度中,多细胞花粉不能形成,主要不是DNA不能复制,而是细胞分裂和细胞壁的形成受阻所致。