Cell-surface interactions of Shewanella oneidensis MR-1 - role of eDNA and nucleolytic activity

在缺氧沉积环境中，异化铁还原细菌在铁氧化物及其相关金属/有机污染物的循环中起着关键作用。在自然界中，不溶的含金属矿物的还原是通过直接的代谢相互作用发生的，在底物表面形成微生物生物膜。微生物-表面相互作用的启动和细菌生活方式转换的启动的分子机制还不是很清楚。这项关于异化铁还原模式生物的拟议研究，将使用全球转录组和蛋白质组图谱来识别对新陈代谢惰性或可接近的表面的粘附性进行差异调节的基因模式。然后，这些将被用来创建荧光和基于LacZ的报告系统，以便对表面附着后的细胞活动进行显微镜监测，并追踪潜在的调节事件和环境刺激。同时，将对通过初步转录分析和转座子突变独立确定的调控系统进行更详细的研究，以参与这一过程。该方法将对新陈代谢和非新陈代谢微生物-表面相互作用的启动产生新的见解。

Dissimilatory iron-reducing bacteria play a critical role in cycling iron oxides and associated metal/organic contaminants in anoxic sedimentary environments. In nature, reduction of insoluble metal-containing minerals occurs through direct metabolic interaction, mediated by the formation of microbial biofilms at the substrate surface. The molecular mechanisms underlying the initiation of microbe-surface interactions and the onset of a bacterial life style switch are not well understood. The proposed study on the model-organism for dissimilatory iron reduction, Shewanella oneidensis MR-1, will use global transcriptomic and proteomic profiling to identify gene patterns differentially regulated on adhesion to metabolically inert or accessible surfaces. These will then be used to create fluorescent and lacZ-based reporter systems in order to microscopically monitor cellular activities following surface adhesion and to track down underlying regulatory events and environmental stimuli. In parallel a regulatory system will be studied in more detail that was identified independently by preliminary transcriptomic analysis and transposon mutagenesis to be involved in that process. The approach will yield novel insights into the initiation of metabolic and non-metabolic microbe-surface interaction.