植物花青素苷生物合成及调控的研究进展

花青素苷( anthocyanin)是植物新陈代谢过程中产生的类黄酮物质,决定被子植物花、果实、种皮、茎、叶和根等的颜色,具有重要的营养价值和药理作用.近年来关于花青素生物合成途径的研究已取得突破,综述了植物花青素苷基因研究现状和发展趋势,包括植物花青素生物合成途径、参与生物合成途径中相关的结构基因和调控基因及功能研究以及影响花青素苷生物合成的环境因素等的研究进展.     

紫杉醇的生物合成途径和参与催化的酶

通过了解紫杉醇生物合成途径和途径中的催化酶 ,特别是催化限速步骤的关键酶以及这些酶的编码基因 ,从而从分子水平对该途径实施人工操纵 ,将是发展先进的生物工艺大量生产紫杉醇的前提。文章介绍了紫杉醇生物合成途径和催化酶类的研究进展 ,并简略讨论了紫杉醇生物合成研究领域所面临的问题     

多氧霉素及其生物合成的研究进展

多氧霉素(Polyoxins)是高效广谱抗真菌核苷类抗生素,在农业上广泛用于防治植物真菌病害。本文综述了多氧霉素化学结构和理化性质,尤其是武汉大学组合生物合成与新药发现(教育部)重点实验室近年来在该抗生素生物合成基因簇的克隆、生物合成途径的阐明以及多氧霉素组合生物合成等多个方面的研究进展与成果,并对今后以多氧霉素为代表的核苷类抗生素的生物合成研究进行了展望。     

紫杉醇生物合成途径及调控研究进展

本文综述了紫杉醇的生物合成途径、代谢调控及基因工程方面的研究进展,总结了代谢调控与基因工程方法提高红豆杉属植物细胞培养紫杉醇合成量的研究状况,并在探讨生物合成途径理论的基础上,对紫杉醇生物合成的限速步骤进行了阐述,指出解决侧链合成的根速步骤问题会显著提高紫杉醇的生物合成量。     

植物类萜生物合成途径及关键酶的研究进展

萜类化合物是植物中广泛存在的一类代谢产物,在植物的生长、发育过程中起着重要的作用。植物中的萜类化合物有两条合成途径:甲羟戊酸途径和5-磷酸脱氧木酮糖/2C-甲基4-磷酸-4D-赤藓糖醇途径。这两条途径中都存在一系列调控萜类化合物生成、结构和功能各异的酶,其中关键酶的作用决定了下游萜类化合物的产量。植物类萜生物合成途径的调控以及该途径中关键酶的研究已成为目前国内外生物学领域的一大热点。综述了植物类萜生物合成途径和参与该途径的关键酶及其基因工程的研究进展,并展望了其应用前景。     

桉叶素生物合成研究进展

作为桉叶油的主要成分,桉叶素是具有多种生物活性的单萜化合物,被广泛应用于药品、食品及化妆品等领域。桉叶油主要从桉树叶提取,该过程耗费大量人力及自然资源,且容易污染环境。近年来,随着微生物代谢工程与合成生物学的快速发展,加上越来越多萜类生物合成途径得到解析,为桉叶素的绿色生产提供了新的途径。对桉叶素的生物合成途径、桉叶素合酶的结构与功能及近年来桉叶素的微生物合成进行了综述,并对利用微生物代谢工程合成桉叶素等单萜化合物的瓶颈问题及解决方案进行了探讨和归纳,为构建高产桉叶素等单萜微生物工程菌株提供参考。     

人参皂苷等萜类化合物生物合成途径及HMGR的研究进展

人参皂苷是人参的主要有效成分之一,属典型的萜类化合物。本文对萜类生物合成途径及HMG-CoA还原酶进行了综述。人参皂苷等萜类生物合成分为甲羟戊酸和丙酮酸两种途径,两者都是以异戊烯基焦磷酸为主要的中间产物。大量研究资料表明HMG-CoA还原酶是甲羟戊酸途径的第一个限速关键酶,这对人参皂苷生物合成途径及其调控的深入研究具有一定的参考价值。     

生长素合成途径的研究进展

生长素是一类含有一个不饱和芳香族环和一个乙酸侧链的内源激素, 参与植物生长发育的许多过程。植物和一些侵染植物的病原微生物都可以通过改变生长素的合成来调节植株的生长。吲哚-3-乙酸(IAA)是天然植物生长素的主要活性成分。近年来, 随着IAA生物合成过程中一些关键调控基因的克隆和功能分析, 人们对IAA的生物合成途径有了更加深入的认识。IAA的生物合成有依赖色氨酸和非依赖色氨酸两条途径。依据IAA合成的中间产物不同, 依赖色氨酸的生物合成过程通常又划分成4条支路: 吲哚乙醛肟途径、吲哚丙酮酸途径、色胺途径和吲哚乙酰胺途径。该文综述了近几年在IAA生物合成方面取得的新进展。     

乳酸高产菌的代谢调控育种思路

简述了乳酸的结构、性质、用途和生产方法;讨论了乳酸的生物合成途径、代谢途径酶系的组成以及代谢调节机制;重点阐述了采用代谢调控手段如何选育乳酸高产菌的育种战略,概述了近年来乳酸高产菌新的育种技术。     

天然产物的生物合成专刊序言

天然产物是创新药物、食品、香料和日化产品等的重要来源,和人民的健康生活息息相关。近年来,随着现代生物学技术和天然产物化学技术的发展和融合,天然产物生物合成研究得到了迅猛的发展。一批天然产物的生物合成途径被解析,许多天然产物生物合成相关的途径酶与后修饰酶被挖掘和功能表征。进一步,这些参与天然产物生物合成的途径酶编码基因被组装到不同的底盘细胞中,利用合成生物学技术构建细胞工厂,用于天然产物的生物合成。此外,包括基因组编辑等新技术在内的生物技术也被用于天然产物的生物合成。为了进一步促进天然产物生物合成研究的发展,《生物工程学报》特组织出版"天然产物的生物合成"专刊,重点阐述了在天然产物生物合成途径的解析,工具酶的挖掘和功能表征以及生物合成技术制备天然产物三方面所取得的研究进展,并展望未来的发展趋势,为天然产物生物合成的进一步发展提供借鉴和指导。     

Biosynthes of polyketide antibiotics by various actinomycin producing Streptomyces species]

A collection of actinomycin-producing Streptomyces strains, their variants with different levels of antibiotic biosynthesis, and recombinant strains were screened in order to select new strains that produce polyketide antibiotics. Screening with the use of the cloned act gene encoding a component of actinorhodin polyketide synthase (PKS) multienzyme complex from Streptomyces coelicolor revealed that many strains tested can synthesize polyketide antibiotics along with actinomycins. A relationship between biosynthetic pathways of actinomycins and polyketides is discussed.     

Biosynthesis of Polyketide Antibiotics by Various StreptomycesSpecies that Produce Actinomycins

A collection of actinomycin-producing Streptomycesstrains, their variants with different levels of antibiotic biosynthesis, and recombinant strains were screened in order to select new strains that produce polyketide antibiotics. Screening with the use of the cloned actgene encoding a component of actinorhodin polyketide synthase (PKS) multienzyme complex from Streptomyces coelicolorrevealed that many strains tested can synthesize polyketide antibiotics along with actinomycins. A relationship between the biosynthetic pathways of actinomycins and polyketides is discussed.     

Isolation of a plasmid from actinomycin C-producing Streptomyces chrysomallus and its characteristics

Until now the identification of plasmids in streptomyces, the producers of actinomycins, has not been reported, although there exist the genetic data on the possible plasmid participation in biosynthesis of these antibiotics. In this paper the data are presented on plasmid identification in two variants of Streptomyces chrysomallus. Plasmids are shown to be identical in both variants differing in productiveness. The restriction map is constructed for this 7000 b. p. plasmid. Plasmid participation in actinomycin biosynthesis and its possible use for molecular cloning in streptomyces are discussed.     

Biosynthesis of the Actinomycin Chromophore: Incorporation of 3-Hydroxy-4-Methylanthranilic Acid into Actinomycins by Streptomyces antibioticus

Actinomycin synthesis by washed mycelia of Streptomyces antibioticus has been conducted in the presence of 3-hydroxy-4-methylanthranilate-(carboxyl-¹⁴C). Incorporation of this compound into actinomycins has been observed, which constitutes further evidence that 3-hydroxy-4-methylanthranilate is an intermediate in actinomycin biosynthesis. The position of the incorporated label has been determined to be within the actinomycin chromophore, and the label appears to be equally distributed between both halves of the chromophore. Incidental to these findings was the observation that the ¹⁴C-labeled actinomycins were subject to rapid reabsorption by the organism with actinomycin V taken up preferentially to actinomycin IV.     

多杀菌素的生物合成

多杀菌素是一种新颖大环内酯类杀虫剂,具有对害虫高效、对环境安全、对哺乳动物低毒的优异特点。介绍了多杀菌素生物合成的步骤,及参与这些合成步骤的有关酶系统和基因簇。通过对刺糖多孢菌中多杀菌素合成基因的克隆鉴定与分析,已基本了解多杀菌素生物合成的限速步骤及相关控制基因,从而可通过遗传工程的办法改造刺糖多孢菌,提高多杀菌素的产量 。     

Evidence of isoprenoid precursor toxicity in Bacillus subtilis

The mevalonic acid (MVA) and methylerythritol phosphate (MEP) pathways for isoprenoid biosynthesis both culminate in the production of the two-five carbon prenyl diphosphates: dimethylallyl diphosphate (DMAPP) and isopentenyl diphosphate (IPP). These are the building blocks for higher isoprenoids, including many that have industrial and pharmaceutical applications. With growing interest in producing commercial isoprenoids through microbial engineering, reports have appeared of toxicity associated with the accumulation of prenyl diphosphates in Escherichia coli expressing a heterologous MVA pathway. Here we explored whether similar prenyl diphosphate toxicity, related to MEP pathway flux, could also be observed in the bacterium Bacillus subtilis. After genetic and metabolic manipulations of the endogenous MEP pathway in B. subtilis, measurements of cell growth, MEP pathway flux, and DMAPP contents suggested cytotoxicity related to prenyl diphosphate accumulation. These results have implications as to understanding the factors impacting isoprenoid biosynthesis in microbial systems.     

2-C-methylerythritol phosphate pathway of isoprenoid biosynthesis as a target in identifying new antibiotics,herbicides, and immunomodulators: A review

Specific inhibitors of 2-C-methylerythritol phosphate pathway (MEP-pathway), including compounds obtained based on its metabolites, may compose a new class of antibiotics combining high efficiency and low toxicity. MEP-pathway of isoprenoid biosynthesis is a promising target in identifying new herbicides, immunomodulators, and other physiologically active compounds.     

The extremely conserved pyroA gene of Aspergillus nidulans is required for pyridoxine synthesis and is required indirectly for resistance to photosensitizers.

Numerous disparate studies in plants, filamentous fungi, yeast, Archaea, and bacteria have identified one of the most highly conserved proteins (SNZ family) for which no function was previously defined. Members have been implicated in the stress response of plants and yeast and resistance to singlet oxygen toxicity in the plant pathogen Cercospora. However, it is found in some anaerobic bacteria and is absent in some aerobic bacteria. We have cloned the Aspergillus nidulans homologue (pyroA) of this highly conserved gene and define this gene family as encoding an enzyme specifically required for pyridoxine biosynthesis. This realization has enabled us to define a second pathway for pyridoxine biosynthesis. Some bacteria utilize the pdx pyridoxine biosynthetic pathway defined in Escherichia coli and others utilize the pyroA pathway. However, Eukarya and Archaea exclusively use the pyroA pathway. We also found that pyridoxine is destroyed in the presence of singlet oxygen, helping to explain the connection to singlet oxygen sensitivity defined in Cercospora. These data bring clarity to the previously confusing data on this gene family. However, a new conundrum now exists; why have highly related bacteria evolved with different pathways for pyridoxine biosynthesis?     

2-C-Methylerythritol phosphate pathway of isoprenoid biosynthesis as a target in identifying of new antibiotics, herbicides, and immunomodulators (Review)

Specific inhibitors of 2-C-methylerythritol phosphate pathway (MEP-pathway), including compounds obtained based on its metabolites, may compose a new class of antibiotics combining high efficiency and low toxicity. MEP-pathway of isoprenoid biosynthesis is a promising target in identifying new herbicides, immunomodulators, and other physiologically active compounds.     

Evidence of Isoprenoid Precursor Toxicity in Bacillus subtilis

The mevalonic acid (MVA) and methylerythritol phosphate (MEP) pathways for isoprenoid biosynthesis both culminate in the production of the two-five carbon prenyl diphosphates: dimethylallyl diphosphate (DMAPP) and isopentenyl diphosphate (IPP). These are the building blocks for higher isoprenoids, including many that have industrial and pharmaceutical applications. With growing interest in producing commercial isoprenoids through microbial engineering, reports have appeared of toxicity associated with the accumulation of prenyl diphosphates in Escherichia coli expressing a heterologous MVA pathway. Here we explored whether similar prenyl diphosphate toxicity, related to MEP pathway flux, could also be observed in the bacterium Bacillus subtilis. After genetic and metabolic manipulations of the endogenous MEP pathway in B. subtilis, measurements of cell growth, MEP pathway flux, and DMAPP contents suggested cytotoxicity related to prenyl diphosphate accumulation. These results have implications as to understanding the factors impacting isoprenoid biosynthesis in microbial systems.