植物遗传转化中选择标记基因的研究进展

标记基因在为植物遗传转化提供方便的同时也存在一些问题,综述了植物遗传转化中常用的选择标记基因、标记基因存在的问题以及解决选择标记基因安全性的策略.     

以木糖异构酶基因为筛选标记的玉米遗传转化

利用木糖异构酶基因作为筛选标记可以在含有不同浓度木糖的培养基上筛选出玉米再生植株,其中50％-100％木糖浓度的总体筛选效果较好,但不同玉米基因型之间筛选的最佳浓度差异很大。通过DNA点杂交、PCR及PCR．Southern印记法检测表明,木糖异构酶基因已经整合到转基因植株中。以木糖作为筛选剂,可以减小潜在的生物安全隐患。     

转基因植物选择标记基因及其安全性问题

就目前使用的选择标记基因和提高选择标记基因安全性的策略进行了评述.     

转基因植物中卡那霉素抗体（Ｋan^r）标记基因的生物安全性

卡那霉素抗性（Kan^r)基因是转基因植物中广泛使用的一类标记基因,其生物安全性受到普遍关注,本文详细讲座了转基因植物中Kan^r基因的漂流及其对自然生态环境的影响,并对Kan^r基因及编码蛋白ＡＰＨ（３′）－Ⅱ的人畜食用安全性进行了综述分析。     

平菇遗传标记筛选初探

本实验以0.5%的溴化镉溶液自然选择法和8-MOP-紫外光(30W)复合处理法,分别对平菇孢子进行处理,初步获得抗性菌株。     

两种筛选标记基因在水稻(Oryza sativa L.)遗传转化中的比较

筛选标记的有效选择(筛选周期及筛选效率)是影响作物基因转化成败的重要因素之一。该文在农杆菌介导水稻转化过程中,比较研究了两个标记基因(hpt和bar基因)对抗性愈伤组织产生时间及出愈率的影响。结果表明：以hpt为筛选标记,抗性愈伤组织出现周期短,出愈率高达20％左右;而bar基因作为筛选标记时,抗性愈伤组织块出现较慢,出愈率仅10％左右。因此,在水稻的农杆菌转化中,仅作为筛选标记,hpt基因的效果要明显优于bar基因。     

遗传标记及其在家禽遗传育种中应用的研究进展

概述了现代分子生物学所发展的各类遗传标记的发展和现状及其在家禽遗传育种中的应用,同时也探讨了数量与质量性状基因定位在动物遗传育种中的应用。     

无筛选标记转基因作物的研究进展

目前,大部分植物遗传转化都要使用选择标记基因,诸如抗生素、除草剂等来筛选转化子,由此而引起的转基因生物安全性问题受到了人们的关注。为了消除转基因作物中的筛选标记,一种全新的策略即无选择标记的转基因技术迅速发展起来。该技术既能够减轻大众对转基因植物中含有选择标记基因而引起的恐惧,又能将多个基因逐个整合到同一作物以实现基因聚合。因此这种新策略有着巨大的应用价值。对获得无筛选标记转基因作物的一些方法及其最新研究进展进行综述。     

丝状真菌遗传转化体系的研究进展

随着现代测序技术的飞速发展,主要丝状真菌的基因组序列相继公布,对丝状真菌基因水平的研究也不断深入,发展高效的遗传转化技术是真菌基因功能研究以及定向改良菌种的前提。近年来,尽管研究者不断优化并开发新的遗传转化方法,然而在丝状真菌中仍然存在转化效率较低、阳性转化子筛选困难等问题。适宜的转化方法和筛选标记对丝状真菌的遗传转化有至关重要的作用。该文综述了丝状真菌遗传转化系统的研究进展,主要从受体细胞的处理、外源基因的整合与表达、常用转化方法和阳性转化子的筛选鉴定等方面进行概述,旨在为今后丝状真菌遗传转化体系的构建提供思路。     

丝状真菌遗传筛选系统的研究及其应用

随着基因组时代的发展,主要丝状真菌基因组测序基本完成而被广泛应用于工业、农业、医药等领域。然而丝状真菌的遗传转化效率极低,为了保证在大量非转化子背景下能筛选到目标转化子,恰当的筛选标记显得尤为重要。目前,在丝状真菌的遗传转化过程中常用的筛选标记可分为两类:药物抗性筛选标记和营养缺陷型筛选标记。但两者均具有一定的局限性,为此科研人员利用最新研究的基因组编辑技术对筛选标记加以修饰改造,以更好地用于遗传筛选。本文综述了目前常用的遗传筛选系统的分子机制及运用基因组编辑技术改造的新型筛选标记理论,为丝状真菌在各领域更广泛的应用奠定基础。     

Genetic tools for <Emphasis Type="Italic">Sulfolobus</Emphasis> spp.: vectors and first applications

Sulfolobus species belong to the best-studied archaeal organisms but have lacked powerful genetic methods. Recently, there has been considerable progress in the field of Sulfolobus genetics. Urgently needed basic genetic tools, such as targeted gene knockout techniques and shuttle vectors are being developed at an increasing pace. For S. solfataricus knockout systems as well as different shuttle vectors are available. For the genetically more stable S. acidocaldarius shuttle vectors have been recently developed. In this review we summarize the currently available genetic tools and methods for the genus Sulfolobus. Different transformation protocols are discussed, as well as all so far developed knockout systems and Sulfolobus-Escherichia coli shuttle vectors are summarized. Special emphasis is put on the important vector components, i.e., selectable markers and Sulfolobus replicons. Additionally, the information gathered on different Sulfolobus strains with respect to their use as recipient strains is reviewed. The advantages and disadvantages of the different systems are discussed and aims for further improvement of genetic systems are identified.     

Development of novel low-copy nuclear markers for Hieraciinae (Asteraceae) and their perspective for other tribes

? Premise of the study: The development of three low-copy nuclear markers for low taxonomic level phylogenies in Asteraceae with emphasis on the subtribe Hieraciinae is reported. ? Methods and Results: Marker candidates were selected by comparing a Lactuca complementary DNA (cDNA) library with public DNA sequence databases. Interspecific variation and phylogenetic signal of the selected genes were investigated for diploid taxa from the subtribe Hieraciinae and compared to a reference phylogeny. Their ability to cross-amplify was assessed for other Asteraceae tribes. All three markers had higher variation (2.1-4.5 times) than the internal transcribed spacer (ITS) in Hieraciinae. Cross-amplification was successful in at least seven other tribes of the Asteraceae. Only three cases indicating the presence of paralogs or pseudogenes were detected. ? Conclusions: The results demonstrate the potential of these markers for phylogeny reconstruction in the Hieraciinae as well as in other Asteraceae tribes, especially for very closely related species.     

转基因植物中的标记基因研究新进展

文章综述了转基因植物中标记基因研究的新进展,主要包括以下3个方面：第一是采用共转化、位点特异性重组和转座子等技术对传统抗性标记基因进行消除,以利于对同一作物进行多次转基因操作;第二是完善各种已应用的以糖类代谢酶基因、耐胁迫酶类基因和绿色荧光蛋白基因等为安全标记基因的转化体系,并大力研究、开发潜在的汞离子还原酶基因、叶绿体合成关键酶基因等作为安全标记基因;第三是着力发展无标记基因、无载体骨架的简单高效转化体系。此外,还展望了安全标记的应用前景。     

A theoretical application of selectable markers in bacterial episomes for a DNA cryptosystem

A theoretical model utilizing the principle of selection for the purposes of DNA cryptography is proposed. A method to enhance the security of DNA cryptosystems that utilize polymerase chain reaction primer keys is presented. Double-encryption systems - encryption systems that have two keys - like the cryptosystem advanced in this paper, are generally more secure than systems that have one key. Two problems with this model are also discussed, and a hypothetical solution to the most major problem is proposed. The chief advantage of this DNA cryptosystem over other DNA cryptosystems is that it has, in theory, two equally secure keys an intruder must break through in order to access a secret message.No experimental analysis has been conducted by the author regarding any of the theoretical methods proposed in this paper.     

分子标记技术在蚕学研究中的应用

介绍了近年来DNA分子标记技术在绢丝昆虫的进化及亲缘关系分析、家蚕品种真实性鉴定、家蚕分子连锁图的构建、基因标记和定位等方面应用的重要进展 ,并展望了家蚕分子标记辅助育种的前景     

Development of EST-PCR markers and monitoring their intrapopulational genetic variation in Picea abies (L.) Karst.

Fifteen cDNA sequences are reported for the European coniferous forest tree species Norway spruce [Picea abies (L.) Karst.], including the results of similarity searches in public electronic databases. The sequences were subsequently employed for the design of specific primer pairs and PCR-based amplification of genomic fragments. For seven primer pairs, polymorphic EST-PCR markers were identified among 18 trees. Their mode of inheritance was verified by analysing single-tree offspring and studying segregation among haploid endosperms in comparison to diploid tissue. Codominant inheritance was indicated for six markers, while one marker was apparently dominant. Variation of the six codominant EST markers was tested by genotyping 110 randomly selected trees in a Bavarian Norway spruce population. For comparison, the same trees were genotyped at 18 enzyme coding gene loci. There were 3.33 alleles per locus for EST markers and 3.00 for isoenzyme gene markers. In general, a trend to more even frequency distributions and larger intrapopulational variation, including observed heterozygosities, was indicated more for EST markers than for isoenzyme gene markers. The benefits of these newly developed EST-PCR markers are outlined with respect to population genetics and ecological genetics. Received: 29 April 2000 / Accepted: 25 August 2000     

微藻与其他微生物共培养的研究进展及应用

化石燃料的挖掘和燃烧导致环境污染以及气候变化.与化石燃料相比,微藻被认为是一种更有前途的生物柴油生产原料,它具有生长速度快、含油量高、不占用耕地的特点.尽管微藻被认为是生产第三代生物燃料的最佳生产者之一,但单独培养微藻容易污染且采收成本高,与化石燃料和传统可再生能源相比缺乏竞争力.利用微藻与其他微生物共培养能够实现自絮...     

Lactone-ring-cleaving enzymes of microorganisms: their diversity and applications

Microbial lactonohydrolases (lactone-ring-cleaving enzymes) with unique characteristics were found. The Fusarium oxysporum enzyme catalyzes the reversible and stereospecific hydrolysis of aldonate lactones and D-pantolactone (D-PL), and is useful for the optical resolution of racemic PL. The Agrobacterium tumefaciens enzyme hydrolyzes several aromatic lactones, and catalyzes the stereospecific hydrolysis of PL like the Fusarium enzyme, but its selectivity is opposite. The Acinetobacter calcoaceticus enzyme catalyzing the specific hydrolysis of dihydrocoumarin belongs to serine-enzyme family, and is useful for enantioselective hydrolysis of methyl DL-beta-acetylthioisobutyrate and regioselective hydrolysis of methyl cetraxate. This enzyme also catalyzes the bromination of monochlorodimedon when incubated with H(2)O(2) and dihydrocoumarin.     

分子标记在啤酒花种质资源研究中的应用

该论文利用分子生物学中常用的DNA分子标记对世界各地现存的野生和栽培的啤酒花种质资源遗传多样性研究的应用进展做一综述。通过查阅和研读20世纪90年代以来发表的各类文献进行归纳总结。发现DNA分子标记相比形态学标记和细胞学标记具有结果准确、稳定的特点,常用的分子标记技术有RAPD、RFLP、ISSR、SSR、AFLP、EST等;研究发现北美洲的啤酒花遗传多样性要高于欧洲的啤酒花,基因变异程度也相对较高;野生啤酒花的基因序列具有丰富的基因多样性,可在分子杂交遗传育种中作为一个种质去改善栽培品种的某些不良性状。因此,利用分子标记研究啤酒花的遗传多样性将对啤酒花的优良育种提供理论指导和技术支持,目前较为理想的技术是SSR和AFLP。     

分子遗传标记技术及其在昆虫科学中的应用

分子遗传标记是随着聚合酶链式反应 (PCR)和Southern杂交等分子生物学技术的飞速发展而出现的遗传学标记技术 ,它突破了以往形态标记 ,细胞学标记和同工酶标记等表达型标记的局限性 ,在揭示物种的遗传变异性研究中发挥着独特的优势。分子遗传标记目前已出现了几十种 ,可依其涉及的位点和反映的多态性的基础分为多位点分子标记和单位点分子标记 ,多位点分子标记反映核苷酸序列的多态性 ,单位点分子标记反映基因座上等位基因的多态性。本文对一些常用的分子标记技术的特点和它们在昆虫系统进化、昆虫分类、昆虫生态、生物防治和特定基因标记等研究中的应用作了介绍。