Phenotypic Characterization of a Female Sterile Mutant in Rice

A female sterile mutant, derived from a spontaneous mutation, was first discovered In rlce （Oryzs satlvs L. sep. Indlca） restorer llne 202R. Wlth normal fiowerlng, the mutant exhlblts an extremely low seed-sattlng rate. When the mutant Is crossed as a pollen donor, the seeds set normally; whereas when It Is used as a pollen recelver, no seeds are obtalned even wlth mlxed pollen gralns of dlfferent varletles sprlnkled over the atlgmas. The fioret of the mutant, conslatlng of slx stamens and one platll, looks the same as that of the wlld type In the malefemale organs, except that less than 10% of the mutant florets have three atlgmas on the ovary. Although the mutant has a low seed-setting rate, Its pollen fertility Is approximately 87.1%, which Is equal to that of the wild type. In addition, more than 90% of the mature embryo sacs of the mutant have complete Inner structures. At every stage after pollination, the sperm, embryo, and endosperm are not found In the mutant embryo sac, whereas the disintegration of the egg cell that does not accomplish fertilization Is visible. Through observetlons with a fluorescence microscope, we have found that the pollen grains germinate normally, whereas the pollen tube abnormally elongates in the style-transmitting tissue. The mutant pollen tubes display various defects In the style, such as slower elongation, conversed elongation, distorted elongation, swollen tips, or branched tips. As a result, the growth of the pollen tubes ceases In the style, and, therefore, the pollen tubes cannot reach the embryo sac and the process of double fertilization Is blocked. Based on these observations, we conclude that this mutant, designated as fs-202R, Is a novel type of female sterile mutation In rice, which causes the arrest of the elongation of the pollen tube.     

布鲁氏菌ery操纵子突变株生物学特性分析

布鲁氏菌ery操纵子参与赤藓醇代谢. 赤藓醇能够促进布鲁氏菌的生长.为进一步研究布鲁氏菌引发宿主流产的分子机制,采用基因重组技术构建布鲁氏菌ery操纵子启动子缺失株（△ery）,通过体内外实验探讨布鲁氏菌ery操纵子的生物学功能. 研究结果显示,获得了布鲁氏菌ery操纵子缺失株;布鲁氏菌ery操纵子缺失株侵染胚 胎滋养层细胞脱落较亲本株明显下降;巨噬细胞CFU计数缺失株作用组和亲本株作用组差异显著（P<0.05）.试管凝集和虎红平板实验结果显示均出现凝集现象;检测血清中细胞因子IL-10和TNF-α的表达水平,△ery诱导机体产生的IL-10和TNF-α明显低于亲本株（P<0.05）.小鼠脾脏细菌CFU计数结果显示,△ery较亲本株毒力明显下降.本研究表明,布鲁氏菌ery操纵子启动子缺失株毒力较亲本株明显下降,为进 一步揭示布鲁氏菌引起流产的致病机制提供了一定的理论依据.     

Characterization of a Cytochalasin D-Resistant Mutant of Entamoeba histolytica

Characterization of a cytochalasin D-resistant mutant of the human parasite Entamoeba histolytica capable of growing at 10 μM cytochalasin is described. The mutant cells also show resistance to 5 mM colchicine and 100 μM cytochalasin B, drugs proved deleterious for wild type trophozoites. The mutants show increased osmotic fragility and electric mobility but reduced phagocytic activity, and agglutination by Concanavalin A. On the other hand pinocytic activity remains unaltered when compared with the wild type cells. Polymerized actin, seen by staining with phalloidin, often appears polarized to one end of the trophozoites and forms few of the endocytic invaginations found in wild type amebas. An altered distribution of part of the actin could explain the differences in surface properties and motility observed in the mutant amebas.     

一个高粱直立叶突变体的表型鉴定和遗传分析

直立叶是构建合理株型和培育密植化栽培品种的重要指标之一.本研究利用甲基磺酸乙酯(EMS)诱变高粱BTX623,获得一株可以稳定遗传的直立叶突变体,暂命名el(erect leaf).该突变体叶片从6叶期开始出现直立性状,直至整个生育期叶片均呈直立状态.抽穗期突变体el植株倒1叶至倒7叶各节位叶长极显著缩短,叶片宽度也显...     

一个新的番茄黄绿叶突变体表型鉴定与遗传分析

植物黄绿叶突变体不但在植物的光合作用、叶绿素的合成代谢途径、叶绿体的遗传分化与发育等一系列基础研究中具有重要作用,而且还可以作为标记性状应用到育种研究上。本研究以前期化学诱变得到的一个番茄黄绿叶突变体为材料,对其主要表型与光合作用特征特性进行鉴定分析,发现突变体从第1片真叶开始变黄,植株矮小,叶片叶绿素含量和净光合速率相对野生型极显著降低,叶绿体类囊体片层结构畸形。突变体和野生型进行正反交,分析其遗传方式。发现其F2群体正常叶与黄绿叶的分离比为3∶1,表明黄绿叶是由单个基因突变引起的隐性性状。本研究为后期的基因定位研究奠定了基础。     

玉米黄绿叶突变体表型鉴定及基因初步定位

叶色突变体是研究光合作用及叶绿体发育的重要材料。开展玉米叶色突变体的相关研究,对光形态建成、光合作用、基因功能注释、蛋白质功能及抗逆性机制的阐述具有重要的理论意义。本研究以黄绿叶突变体ygl-F17138为材料,与玉米自交系B73进行杂交,构建F2分离群体,进行遗传效应分析和基因初步定位。遗传分析表明,该突变性状由单个隐性核基因控制,且能稳定遗传。利用BSR-seq结合连锁分析的方法将该基因初步定位在第3条染色体上一个约9.2 Mb的区间内(chr.3:173087201~182203992),查询该区间内已知基因功能注释,未发现类似前人报道的调控黄绿叶性状基因,说明YGL-F17138基因可能是一个控制玉米黄绿叶发育未被挖掘的候选基因。     

PNP降解相关基因温敏突变株的分离及其特性研究

通过接合转移将质粒pSC123上的转座子Tn5随机插入到DLL-E4基因组DNA中,从大约8,000个突变株中得到1株温度敏感型突变株MT54。根据转座子上的已知序列设计引物以MT54基因组DNA为模板进行PCR扩增,证实MT54的染色体中有转座子插入。MT54在30℃条件下能够以对硝基苯酚(p-nitrophenol,PNP)为唯一碳源生长,但在37℃不能生长。格里斯试色剂法检测NO_2~-的生成情况进一步证明了MT54的这种特性。通过30℃和37℃两种温度条件下MT54和原始出发菌株DLL-E4对PNP和对苯二酚降解情况的比较,推测温敏突变位点可能发生在与PNP降解相关的基因中。     

虎纹捕鸟蛛毒素-I单残基突变体R20A-HWTX-I的化学合成与性质分析

虎纹捕鸟蛛毒素－１（Ｈｕｗｅｔｏｘｉｎ－１,ＨＷＴＸ－１）是从虎纹捕乌蛛（Ｓｅｌｅｎｏｃｏｓｍｉａ ｈｕｗｅｎａ）的粗只同的一种多肽类神经毒素。为了探明该毒素分子中统一的Ａｒｇ残基与其生物学活性的关系,运用固相多肽合成技术和Ｆｍｏｃ化学直接构建了Ａｌａ取代ＨＷＴＸ－１第２０位Ａｒｇ（Ｒ２０）的突变体Ｒ２０Ａ－ＨＷＴＸ－１;将合成的突一置于含谷胱甘肽的缓冲体系中氧化复性后用反相和特殊设计的离子交换Ｈ     

Purification and Characterization of an Endo-Polygalacturonase from a Mutant of Saccharomyces cerevisiae

An extracellular endo-polygalacturonase (PGase) produced by a mutant of Saccharomyces cerevisiae was isolated. The enzyme was regarded, immunologically, as a PGase belonging to the Kluyveromyces marxianus group. The enzyme had properties similar to the PGase from K. marxianus in heat and pH stability, and N-terminal amino acid sequence. However, the enzyme showed different properties in optimum pH and temperature, molecular weight, and reactivity in antiserum against PGase from K. marxianus, indicating that the enzyme has a different molecular structure from the PGase from K. marxianus.     

水稻短根毛突变体Ossrh2的表型分析与基因定位

在粳稻品种中花11为遗传背景的T-DNA突变体库中筛选获得一个遗传稳定的水稻（Oryzasativa）短根毛突变体Ossrh2（Oryza sativa short root hair2）。突变体在苗期表现为根毛数量减少,为野生型的61.4%,根毛长度明显变短,只有野生型的22.8%,同时根毛增粗,根毛形态也发生了变异,局部扭曲膨胀和分叉,除此之外突变体的地上部和根部生长情况与野生型相比没有显著差异。遗传分析表明,该突变性状受1对隐性单基因控制。通过对突变体T2和F2代的分子检测发现,该突变体表型非T-DNA插入引起。利用Ossrh2纯合体和籼稻品种Kasalath杂交构建的F2群体对OsSRH2进行基因定位,发现其与第10号染色体短臂上的SSR（simple sequence repeat）标记RM6370和RM474连锁,遗传距离分别为1.1cM和3.0cM。通过在两标记间发展3个新的STS（sequence-taggedsite）标记,将OsSRH2基因定位于标记S1227和S1531之间,物理距离约为304kb,为进一步克隆OsSRH2打下了基础。     

重组蓖麻、相思子毒素A链嵌合突变体的制备与分析

目的:构建蓖麻毒素(RIC)、相思子毒素(ABR)A链突变体的嵌合体蛋白,实现嵌合体蛋白的可溶性表达、纯化及抗原性分析。方法:采用柔性linker连接RIC A链突变体(mRICAD75AV76MY80A)和ABR A链突变体(mABRAE164AR167L),构建嵌合体基因mRICA/mABRA,将该嵌合体基因亚克隆至原核载体pQE80L构建表达质粒pQE80L-mRICA/mABRA,再转化至大肠杆菌M15获得表达工程菌株M15/pQE80L-mRICA/mABRA,工程菌在18℃经0.1 mmol/L的IPTG诱导14 h,表达的嵌合体蛋白经Ni-NTA亲和层析柱纯化,通过ELISA和Western印迹检测嵌合体蛋白的抗原性。结果:所获得的mRICA/mABRA嵌合体基因经一致性比对分析,与预计嵌合基因的序列一致性为100%,其开放读框全长1572 bp,编码524个氨基酸残基;重组表达质粒pQE80L-mRICA/mABRA经PCR及双酶切鉴定证明构建正确,嵌合体蛋白相对分子质量约为62×103,与预测相符,可溶性的嵌合体蛋白经Ni-NTA亲和层析柱纯化,纯度可达99%;间接ELISA和Western印迹结果表明,嵌合体蛋白能同时与抗RIC多克隆抗体和抗ABR多克隆抗体发生特异的抗原抗体反应。结论:得到的mRICA/mABRA嵌合体蛋白具有良好的抗原性,为研制新型RIC和ABR双价疫苗奠定了重要基础。     

水稻叶色突变体叶绿体发育规律研究

从温敏核不育系水稻'810S'中筛选出一个生长发育正常的淡黄绿叶色自然突变株'标810S',其叶绿素含量约为'810S'的50%,光合速率比野生型高.以'810S'为对照,对'标810S'进行叶片形态、叶肉细胞和叶绿体超微结构以及叶绿体蛋白研究.结果显示,'标810S'的叶长、宽和面积与'810S'相似;叶肉细胞和叶绿体发育稍迟缓,片层结构减少;叶绿体蛋白约为对照的55%,并初步鉴定出与光合作用相关的差异蛋白点13个,其中4个缺失蛋白,包括1个RuBP大亚基缺失.推测该水稻突变体叶色变浅与叶绿体基粒片层减少有关.     

Phenotypic and Genetic Analysis of a Mutant of Heterorhabditis bacteriophora Strain HP88

Induction and characterization of a morphological mutant are described for Heterorhabditis bacteriophora strain HP88. A homozygous inbred line was used as the base population for mutagenesis and genetic analysis of mutations. Mutagenesis was induced by exposing young hermaphrodites to 0.05 M ethyl methanesulfonate. A dumpy mutant (designated Hdpy-l) was isolated from the F₂ generation of the mutagenized population. Morphological studies with light and scanning electron microscopy revealed that the head region of the adult stage was compressed. The head region of the infective juvenile was distorted and the mouth open. Backcross with the original population was successful only between mutant hermaphrodites and wild type males; 50-100 percent of the progeny of this cross maintained the dumpy phenotype, indicating that the ratio between self- and external fertilization of the eggs is > 1 and that the dumpy mutation is recessive.     

Characterization and Fine Mapping of a Novel Rice Narrow Leaf Mutant nal9

A narrow leaf mutant was isolated from transgenic rice （Oryza sativa L.） lines carrying a T-DNA insertion. The mutant is characterized by narrow leaves during its whole growth period, and was named nal9 （narrow leaf 9）. The mutant also has other phenotypes, such as light green leaves at the seedling stage, reduced plant height, a small panicle and increased tillering. Genetic analysis revealed that the mutation is controlled by a single recessive gene. A hygromycin resistance assay showed that the mutation was not caused by T-DNA insertion, so a map-based cloning strategy was employed to isolate the nal9 gene. The mutant individuals from the F2 generations of a cross between the nal9mutant and Longtepu were used for mapping. With 24 F2 mutants, the nal9 gene was preliminarily mapped near the marker RM156 on the chromosome 3. New INDEL markers were then designed based on the sequence differences between japonica and indica at the region near RM156. The nal9 gene was finally located in a 69.3 kb region between the markers V239B and V239G within BAC OJ1212_C05 by chromosome walking. Sequence and expression analysis showed that an ATP-dependent CIp protease proteolytic subunit gene （CIpP） was most likely to be the nal9 gene. Furthermore, the nal9 mutation was rescued by transformation of the CIpP cDNA driven by the 35S promoter. Accordingly, the CIpP gene was identified as the NAL9 gene. Our results provide a basis for functional studies of NAL9 in future work.     

一个酿酒酵母呼吸突变株在高糖胁迫下的生理特性研究

MF11a为甘蔗糖蜜乙醇发酵野生型高产菌株MF1002的呼吸突变体,对糖分的利用能力显著高于MF1002。本文研究了这两菌株应激高糖胁迫的生理特性变化。结果表明,高糖培养条件下,MF11a菌株的生长和乙醇发酵受抑制的程度均明显低于MF1002,培养基的葡萄糖浓度为30%和40%时,其最大菌体密度、最高出芽率和乙醇浓度等已显著高于MF1002,表明MF11a较MF1002具有更强的高糖耐受能力。在30%葡萄糖的胁迫培养条件下,两菌株胞内的总超氧化物歧化酶(SOD)活力、过氧化氢酶活力、过氧化物酶活力,及它们细胞质和线粒体的ATP酶活力均显著上升,说明这五种酶均参与了两菌株的高糖胁迫反应。其中,MF11a的胞内过氧化氢酶活性、过氧化物酶活力、细胞质ATP酶活力在高糖胁迫下的上升幅度显著高于MF1002,表明这三种酶活力可能与MF11a菌株的高糖耐受能力有关,可作为该菌株进一步改造的指导指标。     

棉花矮化突变体的遗传分析

陆地棉科遗２号×中棉完紫的种间杂交衍生后代群体中分离出一株矮秆小叶突变体,经多年选择育成了矮早棉１号。在北京气候条件下,矮早棉１号成熟时,株高只有４５ｃｍ,不到正常陆地棉的１／２。遗传分析揭示矮早棉１号的矮化早熟特性系由两对隐性基因控制,其基因符号定名为ｄ_１和ｄ_２,矮早棉１号为双隐性纯合子,基因型为ｄ_１ｄ_１ｄ_２ｄ_２。正常陆地棉ＴＭ－１、中棉所１２及中棉所１６均为显性纯合子,基因型为Ｄ_１Ｄ_１Ｄ_２Ｄ_２。控制棉花株高的两对基因Ｄ_１／ｄ_１和Ｄ_２／ｄ_２间表现重叠作用。矮早棉１号在棉花早熟育种中有重要价值。     

Characterization and Molecular Mapping of a New Virescent Mutant in Rice

Plant leaves play a significant role in photosynthesis. Normal chloroplast development is critical for plant growth and yield performance. Defect of the chlorophyll in chloroplasts may cause abnormal leaf colors, such as yellow, white, or stripe. Chloroplasts have their own genomes encoding for about 100 genes that are essential for plastid protein synthesis and photosynthesis （Kanno and Hirai, 1993; Sato et al., 1999）. Moreover, over 3000 proteins encoded by plant nuclear genomes target to the chloroplasts and participate in the chloroplast development and/or photosynthesis. Hitherto, a number of plant genes, which encode for enzymes involved in chlorophyll biosynthetic pathways,     

Characterization of a Loss-of-Function Mutant of Gibberellin Biosynthetic Gene LsGA3ox1 in Lettuce

A previous study generated lettuce (Lactuca sativa) mutant lines tagged by retrotransposon Tnt1 from tobacco (Nicotiana tabacum) and identified a homozygous mutant, Tnt6a, that exhibited severe dwarf phenotype. Here we show that Tnt1 is inserted into the intron of gibberellin biosynthetic gene LsGA3ox1 in Tnt6a mutants. Expression analysis suggests that LsGA3ox1 is nearly knocked out in the Tnt6a mutants.     

Chloroplast Composition and Structural Differences in a Chlorophyll-reduced Mutant of Oilseed Rape Seedlings

缺乏叶绿素的油菜突变体的叶绿体组成和结构变化 赵云 杜林方* 杨胜洪 李世崇 张义正 （四川大学生命科学学院,成都610064）