The Texas cytoplasm of maize: cytoplasmic male sterility and disease susceptibility

The Texas cytoplasm of maize carries two cytoplasmically inherited traits, male sterility and disease susceptibility, which have been of great interest both for basic research and plant breeding. The two traits are inseparable and are associated with an unusual mitochondrial gene, T-urf13, which encodes a 13-kilodalton polypeptide (URF13). An interaction between fungal toxins and URF13, which results in permeabilization of the inner mitochondrial membrane, accounts for the specific susceptibility to the fungal pathogens.     

Mitochondrial heredity: a determinant in the toxic response of maize to the insecticide methomyl

Mitochondria isolated from etiolated Texas male-sterile (TMS) cytoplasm maize (Zea mays L.) seedlings were adversely affected by methomyl (Lannate, 90 wettable powder), while those isolated from normal-fertile seedlings were not. In a manner analogous to that reported for Bipolaris (Helminthosporium) maydis (race T) toxin, experiments with TMS mitochondria showed that 1 to 3 millimolar methomyl inhibited the state 4 oxidation rate of combined malate and pyruvate while stimulating that of succinate or exogenous reduced nicotinamide adenine dinucleotide. Similar concentrations of methomyl effected an inhibition of phosphorylation, an increase in the percentage of transmittance of light through mitochondrial suspensions, and a decrease in the density of the mitochondrial matrix. Methomyl (15 millimolar) had little effect on the physiological activity or ultrastructure of isolated normal-fertile mitochondria. These observations provide the opportunity to specifically assess the homogeneity, or lack of it, of a cytoplasmic heritable characteristic in a widely divergent group of higher plants.     

Restriction endonuclease analysis of mitochondrial DNA from normal and Texas cytoplasmic male-sterile maize

Mitochondrial DNA from normal and cytoplasmic male-sterile maize was digested with restriction endonucleases RI from Escherichia coli or dIII from Hemophilus influenzae. Electrophoresis of resulting fragments revealed distinctions between the two cytoplasmic types. These distinctions suggest that factors responsible or cytoplasmic male sterility are located in the mitochondrial DNA, and that the mitochondrial genome is not inherited paternally.     

线粒体蛋白质组学技术及其在植物细胞质雄性不育机理研究中的应用

利用差异蛋白质组学技术,比较研究不育系和保持系花药线粒体蛋白质组的变化,可以较全面地反映与育性相关蛋白质或多肽的表达变化特征,对于了解雄性不育花药败育发生的原因及其生理生化代谢机制具有重要作用。文章通过对植物线粒体蛋白质组学研究技术及其在揭示植物细胞质雄性不育（CMS）机理方面的研究进行综述,提出从线粒体差异蛋白质组学角度来揭示植物CMS的机理,是该领域研究的必然趋势。今后需加深对作物线粒体差异蛋白组学与其CMS机理的研究。此外,随着线粒体蛋白质组数据库的不断完善,蛋白质组学各种方法间的整合和互补,以及与其他学科（如基因组学、生物信息学等）领域的交叉研究,必将深入阐明CMS机理,从而加快植物杂种优势的利用。     

线粒体蛋白质组学技术及其在植物细胞质雄性不育机理研究中的应用

利用差异蛋白质组学技术,比较研究不育系和保持系花药线粒体蛋白质组的变化,可以较全面地反映与育性相关蛋白质或多肽的表达变化特征,对于了解雄性不育花药败育发生的原因及其生理生化代谢机制具有重要作用。文章通过对植物线粒体蛋白质组学研究技术及其在揭示植物细胞质雄性不育（CMS）机理方面的研究进行综述,提出从线粒体差异蛋白质组学角度来揭示植物CMS的机理,是该领域研究的必然趋势。今后需加深对作物线粒体差异蛋白组学与其CMS机理的研究。此外,随着线粒体蛋白质组数据库的不断完善,蛋白质组学各种方法间的整合和互补,以及与其他学科（如基因组学、生物信息学等）领域的交叉研究,必将深入阐明CMS机理,从而加快植物杂种优势的利用。     

Molecular cloning and expression of a human B-cell growth factor gene in Escherichia coli

A human B-cell growth factor (BCGF) (12 kilodaltons) supports the clonal proliferation of B lymphocytes. A clone was isolated that contained the proper structural sequence to encode biologically active, 12-kilodalton BCGF in Escherichia coli and to hybridize to a specific messenger RNA, identified by in vitro translation in Xenopus laevis oocytes. A relatively hydrophobic region of 18 amino acids was found at the amino terminal of the 124-amino acid-long polypeptide. The carboxyl terminal is composed of at least 32 amino acids that are derived from nucleotide sequences bearing significant homology to the Alu repeat family.     

玉米细胞质雄性不育与恢复基因研究进展

玉米作为我国重要的粮、饲两用作物在保障粮食安全,推动社会经济发展和提供工业能源等方面 扮演着关键的角色。细胞质雄性不育是高等植物中普遍存在的生物学现象,玉米细胞质雄性不育可以分为 T 型、 C 型与 S 型 3 种类型。不育基因来源于线粒体基因重排形成嵌合基因,新形成的嵌合基因对花药中小孢子的发 育产生危害导致败育的发生。恢复基因的存在可以消除不育基因的危害,使小孢子正常生长。由于不育基因为 线粒体基因,恢复基因为细胞核基因,对细胞质不育与恢复机理的研究同样是探究质 - 核互作关系的桥梁。同 时对雄性不育系的利用是玉米利用杂种优势的一个重要技术手段,玉米生产上利用细胞质雄性不育对于作物杂 种优势的利用、杂交种的制种都有重要意义,不但能够解放劳动力降低制种成本,而且提高了制种纯度增加产量。 对玉米细胞质雄性不育的分类、特征及近年来发现的玉米细胞质雄性不育基因与育性恢复基因进行概述,并探 讨了玉米细胞质雄性不育应用过程中的问题与发展前景,以其为细胞质雄性不育在生产上的推广利用提供参考。     

Method for Isolating Mitochondrial DNA from Etiolated Tissue of Cabbage

Isolation of high-quality mitochondrial DNA（mtDNA） is an important premise for researching molecular mechanisms in cytoplasmic male sterility of cabbage（Brassica oleracea L.var.capitata）. An efficient protocol for separation and purification of mitochondria and extraction of mitochondrial DNA（mtDNA） from etiolated tissues of cabbage was developed. We took a method combined mannitol density gradient with differential centrifugation, selected appropriate rotational speed, extended DNase I treating time and changed mitochondria cracking condition. The results showed that the extracted mitochondria in this protocol had complete structure, appeared to ellipsoid and had not been contaminated with other impurities under the Jannus Green B staining. The isolated mitochondrial DNA had high purity and yield through detecting the optical density, nuclear specific primer PCR and agarose gel electrophoresis. The results indicated that mitochondrial DNA extracted by this protocol had high quality and enabled to be used in futher genetic studies.     

禾谷类作物编码与雄性不育相关线粒体蛋白核基因筛选策略

植物细胞质雄性不育（CMS）是指植物不能产生具有正常功能的花粉。控制CMS的基因存在于线粒体中,核基因对线粒体基因表达具顺向调节作用,而线粒体对核基因表达具有反向调节作用。目前植物线粒体蛋白组研究主要以营养器官为材料,主要粮食作物如水稻、小麦及玉米等都存在花药小、花期短、同一花序的花药发育不同步等。文章介绍了线粒体起源及植物线粒体蛋白组和植物CMS的研究现状,禾谷类作物花药线粒体蛋白组研究的重要性及困难,提出利用比较基因组学筛选水稻编码线粒体蛋白、与雄性不育相关的核基因的策略,以期为研究禾谷类作物特别是水稻CMS机理提供参考。     

PLAGUE TOXIN: ITS EFFECT IN VITRO AND IN VIVO

The murine toxin of Pasteurella pestis inhibited the respiration of heart mitochondria from the rat and the mouse but had little or no effect on the respiration of mitochondria from the rabbit, chimpanzee, dog, and monkey. Alterations occurred in tile S-T segments of the electrocardiogramus recorded corded from rats injected with (1/4) to 10 LD(50) of toxin, but not in those from rats dying of hemorrhagic shock, hypoxia, intoxication with glucose, or Escherichia coli endotoxin. No abnormalities were observed in electrocardiograms from rabbits injected with large amounts of toxin.     

Manipulating the metazoan mitochondrial genome with targeted restriction enzymes

High copy number and random segregation confound genetic analysis of the mitochondrial genome. We developed an efficient selection for heritable mitochondrial genome (mtDNA) mutations in Drosophila, thereby enhancing a metazoan model for study of mitochondrial genetics and mutations causing human mitochondrial disease. Targeting a restriction enzyme to mitochondria in the germline compromised fertility, but escaper progeny carried homoplasmic mtDNA mutations lacking the cleavage site. Among mutations eliminating a site in the cytochrome c oxidase gene, mt:CoI(A302T) was healthy, mt:CoI(R301L) was male sterile but otherwise healthy, and mt:CoI(R301S) exhibited a wide range of defects, including growth retardation, neurodegeneration, muscular atrophy, male sterility, and reduced life span. Thus, germline expression of mitochondrial restriction enzymes creates a powerful selection and has allowed direct isolation of mitochondrial mutants in a metazoan.     

烟草雄性不育的分子机理研究进展

综述了烟草雄性不育分子机理研究的最新进展，包括：线粒体DNA与雄性不育；叶绿体DNA与雄性不育；核DNA与雄性不育等研究。     

大白菜胞质雄性不育线粒体基因特异分子RAPD标记及克隆

用随机引物对大白菜细胞质雄性不育系及其保持系线粒体DNA的RAPD分析,在不育系与保持系的线粒体基因组间存在明显的差异,用引物S259在不育系中扩增并克隆得到特异片断(mt)S259-600bp,序列分析表明该片断与油菜线粒体基因NADH脱氢酶第四亚基序列有部分相似性,片段与雄性不育的关系还需进一步研究.     

URF6, last unidentified reading frame of human mtDNA, codes for an NADH dehydrogenase subunit

The polypeptide encoded in URF6, the last unassigned reading frame of human mitochondrial DNA, has been identified with antibodies to peptides predicted from the DNA sequence. Antibodies prepared against highly purified respiratory chain NADH dehydrogenase from beef heart or against the cytoplasmically synthesized 49-kilodalton iron-sulfur subunit isolated from this enzyme complex, when added to a deoxycholate or a Triton X-100 mitochondrial lysate of HeLa cells, specifically precipitated the URF6 product together with the six other URF products previously identified as subunits of NADH dehydrogenase. These results strongly point to the URF6 product as being another subunit of this enzyme complex. Thus, almost 60% of the protein coding capacity of mammalian mitochondrial DNA is utilized for the assembly of the first enzyme complex of the respiratory chain. The absence of such information in yeast mitochondrial DNA dramatizes the variability in gene content of different mitochondrial genomes.     

Cloning of Shiga-like toxin structural genes from a toxin converting phage of Escherichia coli

The genes controlling high-level production of Shiga-like toxin (SLT) in Escherichia coli were cloned from the SLT converting phage 933J. This phage was isolated from a strain of E. coli that caused a foodborne outbreak of hemorrhagic colitis. The genes that convert normal E. coli to organisms producing high levels of toxin were cloned into the plasmid pBR328 and expressed in E. coli HB101. DNA restriction mapping, subcloning, examination of the cloned gene products by minicell analysis, neutralization, and immunoprecipitation with antibodies to SLT were used to localize the toxin converting genes and identify them as structural genes for SLT. Southern hybridization studies established that the DNA fragment carrying the cloned toxin structural genes had homology with the DNA of Shigella.     

玉米C型胞质雄性不育与可溶性糖、可溶性蛋白、游离脯氨酸含量的关系

为揭示玉米胞质雄性不育的生化机制,以玉米C型雄性不育系C478及其保持系478、恢复系H01为材料,对叶片及雄穗小花的可溶性糖、可溶性蛋白、游离脯氨酸含量进行比较研究.结果表明:玉米不育系苗期、抽雄期、开花期叶片中可溶性糖含量均显著高于保持系、恢复系;三系间可溶性蛋白含量相差小;不育系除抽雄期外叶片中的游离脯氨酸含量显著高于其保持系、恢复系.玉米雄穗发育过程中,保持系雄穗小花中的可溶性糖含量在雄穗孕育完全但没抽出期(时期Ⅱ)、散粉期(时期Ⅲ)显著高于不育系;不育系小花中各个时期的可溶性蛋白含量均低于其保持系和恢复系,特别在时期Ⅱ、时期Ⅲ显著低于保持系和恢复系;不育系每个时期小花中的游离脯氨酸含量都显著低于保持系和恢复系.     

玉米同核异质雄性不育系花药发育的超微结构研究

研究了玉米Mo_(17)核背景下雄性不育细胞质(T、C、S)与正常细胞质(N)系小孢子发育过程中花药组织的超微结构。结果发现,T型细胞质系减数分裂期绒毡层细胞线粒体嵴和基质出现异常,S型细胞质系单核后期药室中单核小孢子内、外存在着许多具有外壳包裹的圆形至椭圆型小体以及二核花粉期不规则膜状团聚体的出现。     

烟草胞质雄性不育系与保持系线粒体DNA的RAPD分析

用124个10碱基随机引物对烟草2对雄性不育系及其保持系线粒体DNA的RAPD分析表明，不育系与保持系间有112个引物未扩增出多态性片段，占引物总数的92．56％．这反映了不育系和保持系线粒体的同源性。同时，在不育系与保持系的线粒体基因组间也发现了明显的差异，这些差异片段与雄性不育的关系还需进一步研究。     

太空诱变玉米细胞核雄性不育基因与RAPD标记的连锁分析

以姊妹交多代的太空诱变玉米雄性不育材料RP3195(A)×S37(自交系)得到的F2代分离群体(138株)为材料,利用集团分离法(BSA)对太空诱变玉米细胞核雄性不育基因进行了RAPD分析,在152个随机引物中,引物SB SK-14(CCCGCTACAC)和SBSR-3(ACACAGAGGG)分别在可育集团与不育集团之间扩增出多态性产物SBSK-14850、SBSK-14475和SBSR-3400。通过对F2代分离群体中的单株进行连锁分析,初步认为SBSK-14850、SBSK-14475和SBSR-3400与太空诱变玉米细胞核雄性不育基因相连锁,遗传距离分别为49.6,26.6和31.7cM。     

植物细胞质雄性不育与线粒体基因组的分子生物学研究进展

本文综述了植物细胞质雄性不育和线粒体基因组基因及其表达产物的分子生物学研究进展。对细胞质雄性不育遗传因子的细胞器定位、线粒体基因组嵌合基因及其表达产物与细胞质雄性不育的产生的关系、育性恢复基因对线粒体嵌合基因表达的影响、线粒体质粒和RNA 编辑对细胞质雄性不育的影响等细胞质雄性不育的分子生物学研究进展进行了讨论。