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1.
Molecular identification of mutant alleles responsible for certain phenotypic alterations is a central goal of genetic analyses. In this study we describe a rapid procedure suitable for the identification of induced recessive and dominant mutations applied to two Zea mays mutants expressing a dwarf and a pale green phenotype, respectively, which were obtained through pollen ethyl methanesulfonate (EMS) mutagenesis. First, without prior backcrossing, induced mutations (single nucleotide polymorphisms, SNPs) segregating in a (M2) family derived from a heterozygous (M1) parent were identified using whole‐genome shotgun (WGS) sequencing of a small number of (M2) individuals with mutant and wild‐type phenotypes. Second, the state of zygosity of the mutation causing the phenotype was determined for each sequenced individual by phenotypic segregation analysis of the self‐pollinated (M3) offspring. Finally, we filtered for segregating EMS‐induced SNPs whose state of zygosity matched the determined state of zygosity of the mutant locus in each sequenced (M2) individuals. Through this procedure, combining sequencing of individuals and Mendelian inheritance, three and four SNPs in linkage passed our zygosity filter for the homozygous dwarf and heterozygous pale green mutation, respectively. The dwarf mutation was found to be allelic to the an1 locus and caused by an insertion in the largest exon of the AN1 gene. The pale green mutation affected the nuclear W2 gene and was caused by a non‐synonymous amino acid exchange in encoded chloroplast DNA polymerase with a predicted deleterious effect. This coincided with lower cpDNA levels in pale green plants.  相似文献   
2.
产生物表面活性剂菌株的选育   总被引:1,自引:0,他引:1  
以原油为碳源进行微好氧培养筛选到1株产生物表面活性剂的兼性厌氧菌I,其可将界面张力由16.36mN/m降到6.49mN/m。以其为出发菌株,经过紫外和甲基磺酸乙酯复合诱变,得到1株性能优良的变异新菌株,其降低界面张力的能力显著提高,界面张力降低了32.8%。性能评价表明,该菌株能在72℃高温和30%矿化度下生长。有望用于微生物采油研究。  相似文献   
3.
A Nasim  C Grant 《Mutation research》1973,17(2):185-190
Strains showing ethyl methanesulfonate (EMS)-induced replicating instability were genetically analysed to test whether within a given line, mosaics from different plating generations carry a mutation at the same site within the locus. A forward mutation system involving five loci controlling adenine biosynthesis in Schizosaccharomyces pombe was used. Genetic analysis was carried out by interallelic complementation and intragenic recombination tests. The data showed that EMS-induced instabilities are site-specific in being confined to the same recombination unit. This finding is discussed in relation to the possible mechanism(s) of replicating instabilities after different mutagenic treatments in a variety of biological systems.  相似文献   
4.
The phenothiazine psychotherapeutant, triflupromazine (TFP), was studied for mutagenic potential in dominant-lethal, in vivo and in vitro cytogenetic and host-mediated assay procedures. No evidence of gross chromosomal aberrations or point mutations was detected in these assays even at dosage regimens which produced substantial lethality. The effect of the drug on body temperature was measured at the same doses used for mutagenicity testing. A marked and sustained temperature reduction occurs shortly after administration of as little as 10 mg/kg. Due to the pronounced physiological effects at these levels, the validity of mutagenicity studies conducted at the same levels may be seriously questioned.  相似文献   
5.
Nalidixic acid can efficiently induce the reversion of some T4 rII mutations. The great majority of the strains whose reversion can be induced by this antibiotic are also sensitive to the mutagenic action of proflavin, indicating that mutagenicity of nalidixic acid results in base pair addition or deletion. With bacterial host strains resistant to nalidixic acid, the mutagenic effect is greatly reduced but not the effects on phage multiplication. This fact shows that the mutagenic agent is not the nalidixic acid itself but a derivative synthesized in sensitive bacterial strains.  相似文献   
6.
To increase the frequency of stable mutants from cultured anthers of rice, the effects of EMS treatment on callus induction, plant regeneration and mutant induction were investigated according to the timing of treatment after anther inoculation on the medium. The frequency of callus induction was highest in anthers treated with 0.5% EMS 10 days after culture. Anthers treated directly at the initiation of culture exhibited a very low callus induction level, and the such calluses exhibited a poor plant regeneration capacity. The frequency of regeneration of green plants was significantly decreased by EMS treatments immediately after anther inoculation as compared with control. The frequencies of stable mutants were 20.7% and 12.0% in EMS treatments at 10 and 20 days, but unstable mutants were 43.1% and 52.6%, respectively. A total of 14 stable mutants, semidwarf mutants (4 lines), grain-shape mutants (2 lines) and glabrous mutants (8 lines) were selected from doubled haploid lines of the A2 generation. The frequencies of callus induction, green plant regeneration and stable mutants were maximal in anthers treated with 0.5% EMS 10 days after culture.  相似文献   
7.
The mutagenic activity of the monofunctional alkylating agent ethylenimine (EI) was tested with the adenine-3 (ad-3) system in a two-component heterokaryon of Neurospora crassa. The results of forward-mutation experiments showed that EI is a potent mutagen in N. crassa.Genetic analysis of EI-induced ad-3 mutants showed that the frequencies of leakiness, allelic complementation, and non-polarized complementation patterns are similar to those of ad-3 mutants induced by other alkylating agents. It seems, therefore, that in addition to multilocus deletions (which occur at low a frequency), EI-induced mutations probably include base-pair substitutions, frameshift mutations, and other types of intragenic alterations.  相似文献   
8.
将解除了葡萄糖阻遏的纤维素酶高产菌株瑞氏木霉TrichodermareeseiRutC30经EMS诱变后,在酪蛋白平板上筛选出部分蛋白酶缺陷突变菌株T.reeseiRutC30M3。RutC30M3的胞外蛋白酶活力比亲本株降低约74%,但生长特性、产纤维素酶活力等性状与亲本株相同。用携带潮霉素磷酸转移酶基因(hph)的表达质粒pAN7-1分别转化瑞氏木霉RutC30和RutC30M3原生质体,转化结果显示RutC30M3(pAN7-1)对潮霉素的抗性比RutC30(pAN7-1)提高约20%,而Northernblot分析结果显示在两菌株中潮霉素基因转录水平相似,由此证明宿主菌蛋白酶缺陷对保护重组蛋白免于降解有明显作用。蛋白酶缺陷菌株RutC30M3适于作为瑞氏木霉外源基因表达系统中的受体菌株用于大量生产同源与异源蛋白。  相似文献   
9.
Treating pollen with mutagens prior to controlled pollination may facilitate the production of mutant trees for developmental studies and eventual plantation improvement. To establish a suitable dose of the chemical mutagen ethyl methanesulfonate (EMS) for the testing of this hypothesis, pollen of Eucalyptus globulus ssp. globulus and E. grandis was studied in vitro. Pollen germination, pollen tube elongation and generative cell division were examined after 48 h of culture, following exposure to between 0 and 1,000 ppm EMS. Doses of 600 to 1,000 ppm EMS reduced pollen germination in vitro in both species. Doses of up to 1,000 ppm EMS were not observed to significantly impact on either pollen tube length, or generative cell division in vitro of either species. A dose of 600 ppm EMS in paraffin oil is predicted to induce mutation in Eucalyptus species whilst impacting minimally on seed production based on the effect on pollen germination.  相似文献   
10.
Environmental mutagen testing in Escherichia coli and phage lambda   总被引:2,自引:0,他引:2  
S Kondo 《Mutation research》1974,26(4):235-241
  相似文献   
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