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

Craver1350789智力优势：这项研究的总体目标是阐明细菌由于长期接触金属纳米颗粒而可能出现的表型和基因组变化，以及它们对纳米产品制造和公共健康的影响。拟议的项目侧重于填补以下方面的空白：i)确定细菌是否能够适应金属纳米颗粒的长期暴露，同时对对公众健康具有重要意义的药物产生抗药性，以及ii)阐明细菌生理阶段对金属纳米颗粒的应激反应的影响。这两个方面对纳米制造和公众健康都有重要影响。基于金属和金属氧化物的纳米粒子，如银、氧化锌和二氧化钛，目前正被广泛用于工业和消费品中，应用范围从化妆品到水处理。此外，由于萃取程序的优化，稀土元素独特的顺磁性使其使用量急剧增加，生产基于稀土的纳米颗粒和纳米产品是这些材料最具吸引力的用途之一。该项目旨在阐明细菌对金属纳米颗粒的适应性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。生理阶段将通过批量和连续培养试验进行测试。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各种物理化学和环境条件。适应性将使用动力学、表型和基因组参数来确定。然而，在间歇系统中，底物浓度和细胞的生理状态都随着时间的变化而变化，因此这种方法不能正确地评估细菌生理阶段在适应反应中的影响。为了克服这些限制，提出了第二个实验阶段，在这个阶段将使用连续培养。在连续培养中，建立了控制生长的底物的平衡浓度，并且该浓度与培养密度和时间无关。连续培养可以提供比分批培养更准确和可重复性的数据。化学药物已被广泛用于研究压力反应和细菌对抗生素的抗药性的发展；然而，据PI所知，还没有研究使用这种方法系统地评估细菌对纳米颗粒的适应。广泛的影响：该项目将为广泛的受众创造经验学习机会，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，她寻求实现她的学术事业的综合发展，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外的影响，例如对抗生素的抗药性，这可能会对公共健康产生重大影响。这一努力将影响目前用于评估纳米颗粒对微生物的毒理学反应的方案，并向废水处理设施的管理人员提供有关到达其设施的纳米颗粒对健康影响的重要信息。拟议的活动将向正在或可能在农村发展中社区部署或可能部署含有纳米颗粒的使用点水处理技术的非营利组织和利益攸关方提供重要知识；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并激励学生在从事STEM职业的同时担任环境管理员。没有正确的专业技能，学生的成功是不可能实现的。这项建议旨在促进关于纳米毒理学和细菌种群因长期接触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，让他们了解在消费产品中使用金属纳米颗粒的好处和关注的问题。最后，国际和平研究所致力于通过出版物、会议和公共媒体，以尽可能快的方式分发在项目中取得的成果。

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.