PEPTIDE SECONDARY METABOLITE BIOSYNTHESIS IN BACILLUS

单细胞生物以及高等生物的细胞利用低 作为细胞外信号调节细胞的分子量多肽 差异化和专业化。该属的芽胞形成细菌 已知芽孢杆菌能产生许多具有 抗菌活性。最近，有证据表明， 暗示这些多肽是产孢量和能力的调节因子 发展。表面活性物质是一种环状脂肽和强大的生物表面活性物质 由枯草杆菌产生。生产表面活性物质所需的基因已经被 被确认和隔离。其中包括srfA操纵子，它在 参与合成表面活性物质的酶中的至少一种。遗传 有证据表明，srfA也是能力发展所必需的。 以及有效的产孢量，这表明由细菌合成的多肽 SrfA酶可能在发育过程中发挥作用。抄写： SrfA在稳定期细胞中被激活，并很容易被抑制 代谢的碳源和氮源。表面活性物质的生产也 需要昏迷基因，这是一种假定的能力转录调节因子 基因和srfA转录。SFP基因也是表面活性蛋白所必需的 生产，但其主要功能尚不清楚。世界银行的目标是 这里描述的实验是为了鉴定和表征产品 SrfA和SFP基因的同源性，并阐明srfA的作用机制 转录调控。需要srfA才能表达的基因 也将被确定，以便开始审查srfA在 芽孢杆菌的发展。

Unicellular organisms as well as the cells of higher organisms utilize low molecular weight polypeptides as extracellular signals that regulate cell differentiation and specialization. Spore- forming bacteria of the genus Bacillus are known to produce a number of peptides which possess antimicrobial activity. More recently, evidence has emerged which implicates these peptides as regulators of sporulation and competence development. Surfactin is a cyclic lipopeptide and powerful biosurfactant produced by B. subtilis. Genes required for surfactin production have been identified and isolated. These include the srfA operon, which encodes at least one of the enzymes involved in the synthesis of surfactin. Genetic evidence has shown that srfA is also required for competence development and efficient sporulation, which suggests that peptides synthesized by the srfA enzymes may function in developmental processes. Transcription of srfA is activated in stationary phase cells and is repressed by readily metabolized carbon and nitrogen sources. Production of surfactin also requires the comA gene, a putative transcriptional regulator of competence gene and srfA transcription. The sfp gene is also required for surfactin production, but its primary function of is unknown. The goals of the experiments described herein is to identify and characterize the products of the srfA and sfp genes, and to elucidate the mechanisms of srfA transcriptional regulation. Genes that require srfA for their expression will also be identified in order to begin to examine the role of srfA in Bacillus development.