黄曲霉毒素生物合成径调节基因aflR

黄曲霉毒素生物合成途径调节基因在黄曲霉毒素产生过程中发挥十分重要的作用,它为绝大多数黄曲霉毒素合成相关基因的表达所必需。黄曲霉毒素生物合成途径调节基因的启动子中,含有若干真菌转录因子同源物的假定结合位点。AflR蛋白是黄曲霉毒素生物合成途径中的主要正性转录因子,它调节大多数黄曲霉毒素合成相关基因,也包括其自身基因的表达。     

冠毒素生物合成与调控的研究进展

冠毒素是80年代末发现的一种能引起多种植物弥散性黄萎病细菌毒素,它在结构和功能上与在胁迫反应中起作用的植物内源激素茉莉酸甲酯有显著的相似性。本文阐述了冠毒素在生物合成途径与遗传学研究及生物合成调控机制方面的研究进展。     

赤潮藻毒素生物合成研究进展

合成毒素是赤潮藻类的一个常见特征,已知能够产生毒素的微藻有70多种。作为次级代谢产物,藻毒素的产生可能是一种压制或清除其它藻类竞争者的一种反应,在群落演替、种间竞争中发挥重要作用。目前,人们对藻毒素生物合成机理依然知之甚少,相关基因的研究仍无明显突破。利用环境因子诱导毒素生成变化进而分离差异表达基因或者比较不同产毒藻株间基因表达的差异,从中克隆藻毒素生物合成基因似乎是一种极具潜力的研究方向。     

木质素的生物合成及其调控研究进展

木质素是植物体中仅次于纤维素的一种重要大分子有机物质,具有重要生物学功能,其3种主要单体的生物合成途径已经基本清楚。从木质素生物合成及基因工程在调控木质素生物合成中的作用等方面的研究进展进行了综述,并提出了存在的问题及对策。     

林可霉素生物合成及其分子调控研究进展

林可霉素(lincomycin)是由林可链霉菌(Streptomyces lincolnensis)产生的酰胺类抗生素,在临床上主要用于治疗革兰氏阳性菌引起的感染。鉴于其具有高药用价值和经济价值,林可霉素生物合成和分子调控备受关注,并取得了较好的研究进展。本文综述了林可霉素的特征结构和生物合成,并重点介绍了林可链霉菌中林可霉素的分子调控机制等方面的研究进展,有利于深入认识林可链霉菌次级代谢调控网络,为在林可霉素高产菌中改造调控因子或其靶点元件提高产量提供理论指导。     

青蒿素生物合成分子调控研究进展

青蒿素是目前世界上最有效的疟疾治疗药物。通过对青蒿素的生物合成途径,青蒿素生物合成途径的关键酶,青蒿素生物合成的分子调控的介绍,综述了青蒿素生物合成分子调控的最新研究进展。     

花色素苷生物合成的遗传和发育调控

概述了高等植物花色素苷生物合成过程的遗传和发育调控的研究进展。重点介绍花色素苷生物合成的结构基因和调控基困的分子克隆,调控基因对结构基因的调控功能。     

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。     

细菌胞外多糖生物合成转录调控因子研究进展

细菌胞外多糖(Exopolysaccharide,EPS)因其独特的理化特性和生理活性,在食品、制药和化工等领域广泛应用。在食品行业中,黄原胶、结冷胶和热凝胶等细菌EPS备受青睐。转录调控因子能在转录水平上调控eps基因的表达,影响细菌EPS的生物合成。目前细菌EPS转录调控因子的研究报道较少,且多数已知的EPS转录因子调控机制尚未阐明。本文总结了近年来细菌EPS调控因子的研究进展,重点介绍其研究方法和调控机制,以期为细菌EPS转录调控研究提供借鉴。     

植物花青素生物合成中的调控基因

文章概述了植物花青素的生物合成途径,重点介绍了植物花青素调控基因在几个重要的模式植物中的调控特点及其调控机制。     

靛蓝生物合成酶的研究进展

靛蓝色素是人类所知最古老的色素之一,广泛用于食品、医药和印染工业。靛蓝最初由植物中提取获得,作为一种色泽艳丽、无毒无害、能够生物降解的环保型染料,深受青睐。生物合成靛蓝因其绿色、高效、节约土地、安全稳定等优点,作为取代目前植物提取及化学合成的主流途径,受到广泛关注。在过去的几十年中,许多天然酶和工程酶已筛选用于合成靛蓝。本文概述了能够催化靛蓝生物合成的酶及相关应用,并探讨了当前存在的问题和未来研究方向,为推进基于生物合成的靛蓝工业化生产奠定基础。     

Phylogenetic analysis of homologous fatty acid synthase and polyketide synthase involved in aflatoxin biosynthesis

The first two steps of aflatoxin biosynthesis are catalyzed by the HexA/B and by the Pks protein. The phylogenetic analysis clearly distinguished fungal HexA/B from FAS subunits and from other homologous proteins. The phylogenetic trees of the HexA and HexB set of proteins share the same clustering. Proteins involved in the synthesis of fatty acids or in the aflatoxin or sterigmatocystin biosynthesis cluster separately. The Pks phylogenetic tree also differentiates the aflatoxin-related polypeptide sequences from those of other kinds of secondary metabolism. The function of some of the A. flavus Pks homologues may be deduced from the phylogenetic analysis. The conserved sequence motifs of protein domains shared by HexA/B and Pks - namely, β-polyketide synthase (KS), acetyl transferase (AT) and acyl carrier protein (ACP) - have been identified, and the HexA/B and Pks involved in aflatoxin biosynthesis have been distinguished from those involved in primary metabolism or other kinds of secondary metabolism.     

Molecular genetic analysis and regulation of aflatoxin biosynthesis

Aflatoxins, produced by some Aspergillus species, are toxic and extremely carcinogenic furanocoumarins. Recent investigations of the molecular mechanism of AFB biosynthesis showed that the genes required for biosynthesis are in a 70 kb gene cluster. They encode a DNA-binding protein functioning in aflatoxin pathway gene regulation, and other enzymes such as cytochrome p450-type monooxygenases, dehydrogenases, methyltransferases, and polyketide and fatty acid synthases. Information gained from these studies has led to a better understanding of aflatoxin biosynthesis by these fungi. The characterization of genes involved in aflatoxin formation affords the opportunity to examine the mechanism of molecular regulation of the aflatoxin biosynthetic pathway, particularly during the interaction between aflatoxin-producing fungi and plants.     

A versiconal hemiacetal acetate converting enzyme in aflatoxin biosynthesis

Conversion of the aflatoxin biosynthetic intermediate versiconal hemiacetal acetate (VHA) in a cell free extract ofAspergillus parasiticus ATCC 15517 is investigated. The enzymatic reaction is monitored by a method using high performance liquid chromatography (HPLC). The major product of the enzymatic reaction is a water soluble compound not chloroform-extractable at pH 7.5. The product becomes chloroform extractable upon acidification of the reaction medium and is separated and quantitated by reversed-phase HPLC. It is tentatively identified as versiconal hemiacetal alcohol, which is converted to versicolorin C (VC) upon acid treatment.     

藤仓赤霉菌赤霉素生物合成及代谢调控研究进展

赤霉素是最重要的植物生长调节剂之一,在农业生产中得到越来越广泛的应用,具有广阔的市场前景,但其工业化的高生产成本严重制约着它的广泛应用。近年来,利用生物技术提升赤霉素产量日益成为研究热点。赤霉素生物合成是多种酶协同作用的过程,阐明赤霉素的生物合成机制,利用代谢工程策略调控代谢流量,对提高赤霉素产量至关重要。文中综述了当前藤仓赤霉菌赤霉素生物合成途径、关键酶、环境因素、代谢流调控等方面的研究进展,在代谢调控方面进行了展望,以期为实现赤霉素稳产高产提供思路。     

Aflatoxins: Detection,toxicity, and biosynthesis

Aflatoxins are toxic and carcinogenic secondary metabolites produced mainly byAspergillus flavus andAspergillus parasiticus. The aflatoxins present in food and feed are hazardous to both human and animal health. A number of studies have been conducted on the detection, toxicity, biosynthesis, and regulation of aflatoxins due to the discovery of serious aflatoxicosis in farm animals, and the presence of aflatoxins in many food products. There are many reviews that focus on the biosynthesis of aflatoxin, yet there are few examinations of the overall aspects of aflatoxins, including detection, toxicity, and the regulation on biosynthesis. Thus, the goal of this article is to give an overview of the overall aspects of aflatoxins. This review consists of four parts; i) detection methods for aflatoxins, ii) the toxicity mechanism of aflatoxin B1, iii) gene cluster for aflatoxin biosynthesis, and iv) the regulation of aflatoxin biosynthesis.     

蛋白激酶Cla4对黄曲霉生长发育、毒素合成和致病力的影响

黄曲霉Aspergillus flavus是机会性的动物和植物致病性丝状真菌,保守的PAK(p21-activated protein kinases)样蛋白激酶对信号传导、细胞周期进程和细胞形态发生具有重要作用.通过同源重组方法构建敲除突变株(ΔAflcla4),研究Aflcla4基因对黄曲霉营养生长、分生孢子产生、...