Interrogating laboratory-adapted strains of Bacillus subtilis to elucidate the selective pressures of laboratory conditions on multicellular bacterial behaviors

摘要 细菌进行各种多细胞过程，影响其发病机制和环境作用 在自然环境中。然而，很明显，当这些生物体在 在实验室里，它们随着时间的推移经历了重大的基因改造。该项目的长期目标是 了解实验室环境本身如何选择和/或改变健身效果 多细胞细菌的行为，包括生物膜的形成，运动，和分泌的色素次生 代谢物。然而，这些特征是关键的，因为它们对细菌发病机理的影响及其对细菌的毒性。 积极或消极的环境影响。PI将表征B的实验室适应菌株。枯草 分离自在普通实验室培养基LB中生长约300代的群体。 这些菌株在运动性、生物膜形成和色素产生方面具有独特的变化。这个的目标 项目是使用这些实验室适应菌株：1）确定导致 在一个实验室适应的菌株中，不寻常的“社会游泳”行为，令人惊讶的是，这种菌株积极地形成 肉汤培养物中的大的多细胞聚集体。2)量化实验室培养中运动的成本和收益， 因为初步数据表明许多实验室适应的菌株具有降低或改变的运动性。3)识别 由实验室适应菌株和野生型B产生的色素。枯草杆菌菌株NCIB 3610在不同的温度下 在实验室条件下，并量化这些颜料的生产对实验室健身的影响。四、 确定环境和代谢途径负责触发生产色素 通过枯草芽孢杆菌对天然产物进行研究，重点研究了Pulcherrimin;并确定了色素之间的关系 生产和生物膜形成。这项研究是创新的，因为社会游泳是一种新的表型， 可以帮助我们理解多细胞生物的进化。此外，初步数据确定了差异 我们的观察结果与目前解释色素pulcherrimin在芽孢杆菌中作用的模型之间存在差异， 枯草芽孢杆菌，这表明进一步研究这种色素在B。需要subtilis。这很重要 这是由于Pulcherrimin在生物膜形成中的作用及其抗微生物性质。此外，这项工作将 为在实验室中研究多细胞过程（如运动）的科学家提供见解，因为这项工作将 确定实验室环境本身可能产生的影响。此外，这项拟议项目将加强 通过提供支持，让更多的本科生参与进来， 在研究，增加研究能力，并由于锡耶纳的学生人数，将有助于在更大的目标， 增加STEM的多样性。

Abstract Bacteria carry out a variety of multicellular processes that influence their pathogenesis and environmental roles in the natural environment. However, it has become apparent that when these organisms are studied in the laboratory, they undergo significant genetic modification over time. The long-term goal of this project is to understand how the laboratory environment itself selects against and/or changes the fitness effects of multicellular bacterial behaviors including biofilm formation, motility, and the secretion of pigmented secondary metabolites. These features, however, are critical due to their influence on bacterial pathogenesis and their positive or negative environmental effects. The PI will characterize laboratory adapted strains of B. subtilis isolated from populations that grew in the common laboratory medium LB for approximately 300 generations. These strains have distinctive changes in motility, biofilm formation, and pigment production. The goals of this project are to use these laboratory-adapted strains to: 1) Identify the molecular mechanism(s) that causes an unusual “social swimming” behavior in one laboratory adapted strain, as surprisingly, this strain actively forms large, multicellular aggregates in broth culture. 2) Quantify the costs and benefits of motility in laboratory culture, as preliminary data suggest many laboratory-adapted strains have reduced or altered motility. 3) Identify the pigments produced by a laboratory-adapted strain and the wildtype B. subtilis strain NCIB3610 under distinct laboratory conditions, and quantify the effects of the production of these pigments on fitness in the laboratory. 4) Identify the environmental and metabolic pathways responsible for the triggering of production of pigmented natural products by Bacillus subtilis, focusing on pulcherrimin; and determine the relationship between pigment production and biofilm formation. This research is innovative because social swimming is a novel phenotype that could inform understanding of the evolution of multicellularity. Also, preliminary data identify discrepancies between our observations and the current model explaining the role of the pigment pulcherrimin in Bacillus subtilis, suggesting that additional research on the role of this pigment in B. subtilis is needed. This is important due to the role of pulcherrimin in biofilm formation and its antimicrobial properties. Additionally, this work will provide insights to scientists studying multicellular processes like motility in the laboratory, as this work will identify probable effects of the laboratory environment itself. Furthermore, this proposed project will enhance the research environment at Siena College significantly by providing support to involve more undergraduate students in research, increasing research capacity, and due to Siena’s student population, will aid in the larger goal of increasing diversity in STEM.