Control of Hormogonium Differentiation in the Symbiotic Cyanobacterium Nostoc Punctiforme

共生蓝藻点状发菜中激素分化的控制

• 批准号: 0080805
• 负责人: John Meeks
• 金额: $ 36万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2004-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0080805&HistoricalAwards=false
• 关键词: Control; Hormogonium; Differentiation; Symbiotic; Cyanobacterium

0080805MeeksThe nitrogen-fixing cyanobacterium Nostoc punctiforme exemplifies filamentous cyanobacteria (blue-green algae) whose vegetative cells have four developmental alternatives and are the most complex of all bacteria. Depending on the environmental conditions vegetative cells can: grow and divide to continue the vegetative growth cycle, transiently differentiate into motile filaments called hormogonia, transiently differentiate into resting cells called akinetes, or terminally differentiate into heterocysts, the sites of nitrogen fixation. This project focuses on identifying the regulatory mechanisms involved in hormogonium differentiation and behavior. Motile hormogonium filaments serve in the colonization of new habitats and as the infective units in establishment of symbiotic associations with plants and fungi by the Nostoc. Cyanobacteria are important producers of reduced carbon and nitrogen for other organisms in maintaining steady state environmental conditions. In symbiotic associations with lichens for example, nitrogen-fixing cyanobacteria contribute to the consumption of atmospheric carbon dioxide in poor soils and lessen the extent of global warming. This project has two overall objectives. 1. Determine the extent of differential gene expression during hormogonium differentiation, using two dimensional protein gel electrophoresis to identify differentially synthesized proteins, determine the amino acid sequence of selected proteins and use the N. punctiforme genome data base to identify the corresponding genes that encode the proteins. 2. Characterization of a set of genes, whose synthesized proteins may function in the production of a metabolic compound that represses hormogonium differentiation. Specific focus will be on the activity of the hypothetical transcriptional repressor of the genes. The results of this study will be of value in addressing questions of the hierarchy, integration and evolution of regulatory pathways in developmental biology using

0080805 Meeks固氮蓝藻Nostoc punctiforme是丝状蓝藻（蓝绿藻）的一种，其营养细胞有四种发育选择，是所有细菌中最复杂的。根据环境条件，营养细胞可以：生长和分裂以继续营养生长周期，短暂分化为称为藻殖体的运动丝，短暂分化为称为动丝的静止细胞，或最终分化为异形胞，固氮的位点。该项目的重点是确定参与Hormogonium分化和行为的调控机制。能运动的藻殖体丝在念珠藻新生境的定殖中起作用，并作为感染单位与植物和真菌建立共生关系。蓝藻是维持稳定环境条件的重要生产者，为其他生物提供还原碳和氮。例如，在与地衣的共生关系中，固氮蓝藻有助于消耗贫瘠土壤中的大气二氧化碳，并减轻全球变暖的程度。该项目有两个总体目标。1.确定在藻殖体分化过程中差异基因表达的程度，使用二维蛋白质凝胶电泳鉴定差异合成的蛋白质，确定所选蛋白质的氨基酸序列，并使用N. punctiforme基因组数据库，以确定编码蛋白质的相应基因。 2.一组基因的特征，其合成的蛋白质可能在抑制藻殖体分化的代谢化合物的产生中起作用。具体的重点将放在假设的基因转录抑制因子的活性上。本研究的结果将是有价值的，在解决问题的层次，整合和进化的调控途径在发育生物学使用