CAREER: Bacterial adaptation mechanism to chronic exposure to nanoparticles and its implications to nanomanufacturing and public health

Craver 1350789智力价值：这项研究的总体目标是阐明细菌由于长期暴露于金属纳米颗粒而可能出现的表型和基因组变化及其对纳米产品制造和公共卫生的影响。拟议项目的重点是填补有关需要的差距：i）确定细菌是否可以适应长期暴露于金属纳米粒子，同时发展耐药性的药物对公共卫生的重要性和ii）阐明细菌的生理阶段的影响对金属纳米粒子的压力反应。这两个方面对纳米制造和公共卫生都有重要影响。基于金属和金属氧化物的纳米颗粒，例如银、氧化锌和二氧化钛，目前广泛用于从化妆品到水处理的应用范围的工业和消费产品中。此外，由于提取程序的优化，稀土元素的使用由于其独特的顺磁性而急剧增加，并且基于稀土的纳米颗粒和纳米产品的生产是这些材料最有吸引力的用途之一。该项目旨在阐明细菌对金属纳米颗粒的适应是否取决于金属纳米颗粒的组成，物理化学性质和/或细胞的生理阶段。将使用分批和连续培养试验检测生理阶段。高通量批量测试将用于筛选可能导致细菌适应金属纳米颗粒的广泛的物理化学和环境条件。适应将使用动力学、表型和基因组参数来确定。然而，在分批系统中，底物的浓度和细胞的生理状态都作为时间的函数而变化，因此细菌的生理阶段在适应反应中的影响不能用这种类型的方法适当地评估。为了克服这些局限性，提出了第二个实验阶段，其中将使用连续培养。在连续培养中，建立生长控制底物的平衡浓度，并且该浓度与培养物的密度和时间无关。连续培养可以提供比从分批培养获得的数据更精确和可重复的数据。恒化剂已广泛用于研究应激反应和细菌对抗生素的耐药性;然而，据PI所知，没有研究系统地评估细菌使用这种方法对纳米颗粒的适应性。该项目将为广大观众提供体验式学习的机会，包括K-12教师和学生，本科生，研究生和基于金属纳米颗粒的产品的用户。通过这些活动，PI旨在实现她的学术生涯的综合发展，同时为科学发现，教育和社会繁荣做出贡献。这项研究还可能确定意想不到的影响，例如对抗生素的耐药性，这可能对公共卫生产生重大影响。这项工作将影响目前用于评估纳米颗粒对微生物的毒理学反应的协议，并为废水处理设施的管理人员提供有关纳米颗粒对健康影响的重要信息。拟议的活动将为正在或可能在农村发展中社区部署含有纳米颗粒的水处理技术的非营利组织和利益攸关方提供重要的知识;这将最大限度地减少对人类健康和环境的潜在负面影响。该项目的活动将吸引和激励学生追求STEM职业，同时成为环境管理员。学生的成功不能没有正确的专业技能集实现。该提案旨在促进有关纳米毒理学和细菌种群因长期暴露于纳米颗粒而产生的应激反应的信息。该项目的活动将吸引和激励具有不同教育和经验背景的人。PI将为教师和学生提供一系列机会，以了解在消费品中使用金属纳米颗粒的好处和担忧。最后，PI致力于通过出版物、会议和公共媒体以最快的方式传播项目所取得的成果。

Craver1350789Intellectual merit: The overall goal of this research is to elucidate the phenotypic and genomic changes that bacteria can present due to chronic exposure to metal nanoparticles and their implications to the manufacture of nano-based products and public health. The proposed project focuses on filling the gap regarding the need to: i) determine if bacteria can adapt to chronic exposure to metalnanoparticles and simultaneously develop resistance to pharmaceuticals of importance to public health and ii) to elucidate the impact of the bacterial physiological stage on the stress-response to metal nanoparticles. Both of these aspects have important implications for nano-manufacturing and public health. Metal- and metal oxide-based nanoparticles, such as silver, zinc oxide, and titanium dioxide, currently are being used extensively in industrial and consumer products for applications that range from cosmetics to water treatment. Also, due to the optimization of extraction procedures, the use of rare earth elements has increased sharply due to their unique paramagnetic properties, and the production of REE-based nanoparticles and nano-based products is one of the most attractive uses of these materials. This project proposes to elucidate whether bacterial adaption to metal nanoparticles depends on the composition of the metal nanoparticles, physicochemical properties, and/or the physiological stage of the cells. The physiological stage will be tested using batch and continuous culture tests. High-throughput batch tests will be used to screen a wide range of physicochemical and environmental conditions that could lead to bacterial adaptation to metal nanoparticles. Adaptation will be determined using kinetic, phenotypic, and genomic parameters. However, in batch systems, both the concentration of the substrate and the physiological state of the cells change as a function of time, therefore the impact of the physiological stage of the bacteria in the adaptation response cannot be assessed properly with this type of approach. To overcome these limitations, a second experimental phase is proposed in which a continuous culture will be used. In the continuous culture, an equilibrium concentration of the growth-controlling substrate is established, and this concentration is independent of the density of the culture and time. A continuous culture can provide more precise and reproducible data than those obtained from batch cultures. Chemostats have been usedextensively to study the stress response and bacteria's development of resistance to antibiotics; however, to the best knowledge of the PI, no study has systematically evaluated the adaptation of bacteria to nanoparticles using this approach.Broader Impacts: This project will generate experiential learning opportunities to a wide audience, consisting on K-12 teachers and students, undergraduate students, graduate students and users of metal nanoparticle-based products. Through the activities, the PI seeks to achieve an integrative development of her academic career while contributing to scientific discovery, education, and societal prosperity. This study also is likely to determine unintended impacts, such as resistance to antibiotics, which can have a significant impact on public health. This effort will impact the current protocols used to assess the toxicological response of nanoparticles on microorganisms and provide important information to managers of wastewater treatment facilities concerning the health impacts of nanoparticles that reach their facilities. The proposed activities will provide important knowledge to non-profit organizations and stakeholders who are deploying or may deploy point-of-use water treatment technologies containing nanoparticles in rural, developing communities; this will minimize potential negative effects on human health and the environment. Activities from this project will engage and inspire students to pursue STEM careers while being environmental stewards at the same time. Student success cannot be achieved without the right professional skill set. This proposal seeks to promote information on nanotoxicology and the stress-response of bacterial populations due to chronic exposure to nanoparticles. Activities from this project will engage and inspire people with diverse educational and experiential backgrounds. The PI will elaborate a series of opportunities for teachers andstudents to understand the benefit and concerns about the use metal nanoparticles in consumer products. Finally, the PI is committed to distributing the results obtained in the project in the fastest manner possible, through publications, conferences, and the public media.