工业微生物物理诱变育种技术的新进展

物理诱变技术是当今工业微生物育种中最重要、最有效的技术之一。传统的物理诱变技术主要有紫外线、X射线、γ射线诱变等,它们已在包括青霉素、"-淀粉酶等几乎所有的工业微生物菌种的诱变选育中发挥了巨大的作用。多数菌株在多次重复使用传统诱变源时往往出现抗性饱和的现象。太空环境、离子束、激光等是20世纪70～80年代逐渐兴起的新型诱变技术,因它们具有诱变谱广和在一定程度上能克服菌株对传统诱变源的抗性饱和等优点,而广受工业微生物育种工作者的欢迎。现就空间、离子束、激光等诱变育种技术的作用特点、诱变机理、应用及前景进行阐述。     

大豆诱变育种研究四十年

本文简要阐明我所大豆诱变育种研究四十年来,研究确定的可行诱变技术,创造的优良遗传变异类型。先后采用＾６０Ｃｏγ－射线,Ｘ－射线,热中子,ＥＭＳ,ＮａＮ３等诱变因素处理以及有性杂交与诱变结合的技术,育成１３个优良大豆品种,累计种植面积４３２万公顷。还创造出一些极早熟,高蛋白、低亚麻酸、高油,高亚油酸,抗病等优良突变体。研究表明,人工诱变,及其与有性杂交相结合技术,已经成为大豆遗传改良的有效技术手段。     

黄霉素高产菌株的选育

目的:为了获得黄霉素高产菌株。方法:进行了一系列的诱变筛选。以加纳链霉菌(Streptomyces ghanaesis)SgWE-11为出发菌株,采用紫外线诱变,以其自身代谢物黄霉素作为筛选因子。结果:获得一株遗传稳定且黄霉素发酵效价比出发菌株高出170.25%的菌株。对该菌株采用亚硝酸诱变,并以链霉素作为筛选因子时得到一株效价值为875u/mL的高产菌株SgWE-25,比出发菌株SgWE-11提高了4.4倍。传代结果表明,在传代的同时结合自然分离,可以保持稳定的产抗特性。     

黑龙江地区辐射诱变育种及应用研究

本文阐述了黑龙江省近期利用辐射诱导与享体生物技术,远缘杂交,有性杂交相结合,以及辐射诱变处理纯基因型品种（系）等技术方法,选育粮食,经济和蔬菜作物新品种１３个,累计推广面积１００万公顷,创造具有突出特性的突变体丰富了种质资源,结果表明辐射诱变与其他方法相结合,能够扩大变异谱,提高变异率,缩短育种周期等特点。     

植物诱变技术的研究进展

植物诱变技术是指利用外界因素加快物种遗传变异,在短期内获得有利用价值的突变体,为培育新种质、新品种及基因功能的研究等创造条件。相对于自然的选择,诱变技术具有高频率、广突变、周期短等特性。主要论述了常用的化学诱变、物理诱变、空间诱变和生物诱变等诱变手段,并详细介绍了上述诱变技术的诱变机理、生物学效应、常用的诱变方式及其在植物应用中的研究现状。针对现行各种诱变技术的不足提出了今后努力的方向。     

空间诱变在微生物菌种选育上的研究进展

空间诱变是一种新型有效的微生物育种手段。本主要综述国内外微生物空间条件诱发微生物突变的特点、生物学、细胞学、当代生理损伤效应、突变的机理以及育种中已取得的进展,并提出了存在的问题和今后研究的发展方向。     

黑曲霉单宁酶高活性菌株的诱变选育*

以黑曲霉（Ａｓｐｅｒｇｉｌｌｕｓ ｎｈｉｇｅｒ）Ｎｏ．１３为出发菌株,经紫外线诱变处理,获得一株制备原生质体的起始菌,该菌株单宁酶活性比Ｎｏ．１３提高５５％,并对其制备原生质体的条件进行了研究,在优化方案基础上,紫外诱变原生质体,诱变株经筛选,最后得到一株具有稳定遗传性的单宁酶高活性菌株,在摇瓶培养基中进行生物转化实验,连续传代１０次,结果显示发酵液中没食子酸浓度始 维持在２２．８－２３．９ｍｇ／     

微波诱变育种研究及应用进展

介绍了微波的生物效应及诱变机理,同时较为系统地介绍了微波诱变在农业、畜牧业及工业育种上的研究进展及成果。此外还对研究中的不足方面进行了阐述,并预测了今后的研究方向。     

植物抗逆诱变育种技术研究进展

随着分子生物学技术的飞速发展,通过基因工程方法可以更快更好地获得农作物抗逆新品种,其首要任务是通过分离相应的表型改变的突变体来鉴定、克隆在胁迫条件下表达模式发生改变的基因。主要介绍几种常用的及最新的突变体诱变和筛选技术,并分析每种技术的优缺点。     

木聚糖酶高产菌株的诱变*

出发菌株Aspergillus niger M1经过紫外线诱变得到一株木聚糖酶活力提高30％的突变株A．niger J506。木聚糖酶谱带检测发现,突变株成熟发酵液中有3种类型的木聚糖酶,而出发菌株中只有两种。经过正交试验得出突变株产酶的最佳发酵条件为：主碳源浓度4％、麸皮与玉米芯的比例为5：5、葡萄糖浓度0．1％、草酸铵浓度2．0％,培养基初始pH为5．0,250mL三角瓶的装液量为100mL。     

利用番茄突变体进行功能基因组学研究

利用番茄突变体进行遗传学研究和育种已有几十年的历史,然而能从分子水平上识别的番茄突变体却为数不多。目前已经获得了大量的番茄序列信息,但仅明确了少数基因的功能。应用饱和突变群体的发展方向,检测突变体和挖掘序列数据的新方法,架起了研究番茄基因和其功能之间的桥梁。     

Identification of a hotspot for transformation of Neisseria meningitidis by shuttle mutagenesis using signature-tagged transposons

Shuttle mutagenesis using signature-tagged transposons was employed to generate a library of individually tagged mutants of the Neisseria meningitidis strain B1940, which belongs to serogroup B. The use of tagged transposons allowed us to monitor for enrichment for single mutants during the process of shuttle mutagenesis, by amplification of the tags and subsequent sequence determination. Enrichment of a single clone occurred during the transformation of the meningococci with transposon-containing plasmid DNA. Sequence determination around the site of transposon insertion revealed that the transposon had mutagenized a previously unknown locus, which was designated hrtA (high rate of transformation). hrtA-mediated transformation was independent of TnMax5 and tag sequences, and it most probably involved recombination events. The hrtA locus is restricted to meningococci and gonococci and is present in few apathogenic neisserial species. Chromosomal mapping of hrtA and six further hrt sites revealed a random distribution of highly transforming DNA fragments on the meningococcal chromosome. In conclusion, our data demonstrate that shuttle mutagenesis of naturally competent bacteria using signature-tagged transposons allows the isolation of chromosomal DNA fragments, which exhibit a high transformation efficiency, and which, therefore, are likely to be involved in horizontal gene transfer. Received: 12 January 1998 / Accepted: 30 April 1998     

诱变选育高产海藻糖的酵母菌株

以酿酒酵母Saccharomyces cerevisiae HY01为出发菌株,分别对其进行化学诱变和紫外诱变。选用5-溴尿嘧啶和盐酸平阳霉素两种低毒性诱变剂联合使用,通过均匀设计确定了两种诱变剂的最佳配比即5-Bu浓度为300umol/L、平阳霉素浓度为5umol/L时,获得一定数量的正突变株,最高海藻糖含量是15．98％。在紫外诱变过程中经摇瓶初筛、复筛获得了高产海藻糖菌株,其海藻糖含量为19．52％,比出发菌株提高了35％。     

Site-directed mutagenesis using positive antibiotic selection

Various mutsgenesis protocols have been established that use the hybridization of a mismatched oligonucleotide to prime DNA synthesis on an M13 phagemid template. For efficient mutagenesis, all of these methods require a means to select for the mutant strand before or during amplification in anEscherichia coli host. In the Altered Sites II protocol, the mismatched oligonucleotide and an oligonucleotide that restores antibiotic resistance to the phagemid are simultaneously hybridized to the template and coupled by DNA synthesis and ligation. The restored antibiotic resistance is then used to select only those phagemids which incorporate the antibiotic repair oligonucleotide. Generally, between 60 and 90% of the phagemids recovered will incorporate both oligonucleotides. This method provides a simple an efficient technique for introducing specific mutations into DNA.     

复合诱变选育林肯霉素高产菌株

以林肯链霉菌9502(Streptomyces lincolnensis9502)为出发菌株,进行NTG诱变处理,并用高效的琼脂块培养法对菌株进行筛选,得到产林肯霉素相对效价提高35.4%的变异株9502-7。对9502-7菌株孢子采用紫外线处理,得到变异高产菌株9502-7-12,其相对效价较出发菌株提高50%以上。     

Site-directed mutagenesis of the CP 47 protein of photosystem II: alteration of conserved charged residues which lie within lethal deletions of the large extrinsic loop E

The intrinsic chlorophyll-protein CP 47 is a component of photosystem II which functions in both light-harvesting and oxygen evolution. The large extrinsic loop E of this protein has been shown to interact with the oxygen-evolving site. Previously, Vermaas and coworkers have produced a number of deletions within loop E which yielded mutants which were unable to grow photoautotrophically and which could not evolve oxygen at normal rates. During the course of our site-directed mutagenesis program in Synechocystis 6803, we have altered all of the conserved charged residues which were present within six of these deletions. All ten of these mutants were photoautotrophic and evolved oxygen at normal rates. We speculate that the severe phenotypes of the deletion mutants observed by Vermaas and coworkers in due to large structural perturbations in the extrinsic loop E of CP 47.     

Pentapeptide scanning mutagenesis: encouraging old proteins to execute unusual tricks

Pentapeptide scanning mutagenesis is a facile transposon-based procedure for the random insertion of a variable five amino acid cassette into a target protein. The analysis of a library of proteins harbouring pentapeptide insertions can provide invaluable information on the essential and inessential regions of a target protein, as well as revealing surprising aspects of target protein function and activity.