AFLATOXIN B-1 BIOSYNTHESIS IN ASPERGILLUS PARASITICUS

描述：(改编自调查人员的摘要)总体目标 这项研究项目的目的是了解 寄生曲霉黄曲霉毒素B1生物合成的调控。在工作中 假设黄曲霉毒素B1的生物合成是在 转录水平。提出了以下具体目标来进行测试 这一假设：(1)克隆编码催化黄曲霉毒素的酶的基因 寄生曲霉突变体(“受阻”)的遗传互补合成 在黄曲霉毒素生物合成中缺乏独特的酶步骤 利用粘粒文库进行转化的途径；以及(2)表征 克隆基因的遗传组织和表达：a)核苷酸 序列分析，b)Southern和Northern分析，c)S-1核酸酶 D)横向交变磁场凝胶电泳(TAFE)。 希望对控制这种合成代谢的机制的阐明 途径将为抑制黄曲霉毒素的生物合成提供靶点 监管方案的变更。从长远来看，这可能会导致 应用黄曲霉毒素防治采前黄曲霉毒素的研究 这一途径的生物/化学抑制物，竞争性排除 非黄曲霉毒素，或寄主植物的基因改造。自.以来 次生代谢物的转录调控可能涉及共同 不同真核生物属之间的调控元件黄曲霉毒素 途径可能也为理解生物合成提供了一个模型。 其他影响公众健康的霉菌毒素和有毒次生代谢物 和食品安全。

DESCRIPTION: (Adapted from the investigator's abstract) The overall goal of this research project is to understand the molecular mechanisms which regulate aflatoxin B1 biosynthesis in Aspergillus parasiticus. The working hypothesis is that aflatoxin B1 biosynthesis is regulated at the transcriptional level. The following specific aims are proposed to test this hypothesis: (1) Clone genes encoding enzymes which catalyze aflatoxin biosynthesis by genetic complementation of A. parasiticus mutants ("blocked mutants") deficient in unique enzymatic steps in the aflatoxin biosynthetic pathway by transformation with a cosmid library; and (2) characterize the genetic organization and expression of the cloned genes by: a) nucleotide sequence analysis, b) Southern and Northern analysis, c) S-1 nuclease analysis, and d) transverse alternating field gel electrophoresis (TAFE). It is hoped that elucidation of the mechanisms controlling this anabolic pathway will provide targets for inhibition of aflatoxin biosynthesis by alternation of the regulatory scheme. In the long term, this may lead to prevention of preharvest aflatoxigenesis by application of biological/chemical inhibitors of this pathway, competitive exclusion by nonaflatoxigenic aspergilli, or genetic modification of host plants. Since transcriptional regulation of secondary metabolites may involve common regulatory elements among different eukaryotic genera, the aflatoxin pathway may provide a model for also understanding the biosynthesis of other mycotoxins and toxic secondary metabolites that impact public health and food safety.