EAGER: The Bacterial Magnetosome may be a Potential Energy-Harvesting Pseudo-organelle for Magnetotrophy

EAGER：细菌磁小体可能是磁营养学的潜在能量收集伪细胞器

• 批准号: 2038207
• 负责人: Steven Lower
• 金额: $ 28.2万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2038207&HistoricalAwards=false
• 关键词: EAGER; Bacterial; Magnetosome; may; Potential

Magnetotactic bacteria (MTB) have evolved a unique suite of genetically-encoded proteins that are used to synthesize magnetic crystals within an intracellular compartment called the magnetosome. The conventional wisdom is that the magnetosome functions as a sort of internal compass enabling these cells to navigate to their ideal niche using the Earth's magnetic field as MTB swim through bodies of water. While this is an elegant explanation for magnetotaxis, the disparity between the high cost of synthesizing the magnetosome and infrequent alignment of MTB in nature suggests another function. This proposal will investigate the potentially transformative hypothesis that the magnetosome is not used for navigation/orientation but rather it is part of a previously unknown form of metabolism. If this hypothesis is validated then this would add a radically different form of metabolism (magneto-trophy) to established pathways to generate energy like autotrophy and heterotrophy. This new form of metabolism would actually be widespread because MTB are found in just about any environment with liquid water and these bacteria evolved billions of years ago. Knowledge gained from this research will be of great interest to educators across broad disciplinary bounds and promote the progress of science by helping to address fundamental questions integral to the connection between life science and physical science. These research activities will promote STEM training for underrepresented minority students as well as high school teachers embedded in the investigators' labs. Experiments will be performed to test whether the magnetosome plays a role in generating metabolic energy for MTB. Custom-made growth chambers will be used to culture MTB under a range of external magnetic-field strengths. Bacteria specimens will include wild-type strains of MTB and mutants that lack the genetic repertoire to synthesize their internal magnets. Magnetic measurements will be used to determine the presence (or absence) of the magnetosome and characterize the field-strength of internal magnetite in wild-type cells. Bacteria growth and activity will be monitored through absorbance measurements, cell counts, swimming speed, and assays for energy-carrying molecules. Omics and incorporation of isotopically-labeled compounds for wild-type versus mutant strains will permit identification of gene networks and products (proteins and metabolites) impacted by magnetic fields. Integration of data from these distinct yet complementary experiments will allow to carefully test the novel hypothesis that the magnetosome evolved to maximize energy uptake and/or endure in organic-carbon depleted environments that MTB often occupy in nature.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

趋磁细菌（MTB）已经进化出一套独特的遗传编码蛋白，用于在称为磁小体的细胞内隔室中合成磁性晶体。 传统观点认为，磁小体的功能就像一种内部指南针，使这些细胞能够在MTB游泳通过水体时利用地球磁场导航到理想的生态位。 虽然这是对趋磁性的一个优雅的解释，但合成磁小体的高成本与自然界中MTB的罕见对齐之间的差异表明了另一种功能。 该提案将调查潜在的变革性假设，即磁小体不用于导航/定向，而是以前未知的代谢形式的一部分。 如果这一假设得到验证，那么这将为已建立的产生能量的途径（如自养和异养）添加一种完全不同的代谢形式（磁营养）。 这种新的代谢形式实际上是广泛存在的，因为MTB几乎存在于任何有液态水的环境中，这些细菌在数十亿年前进化而来。 从这项研究中获得的知识将引起广泛学科范围内教育工作者的极大兴趣，并通过帮助解决生命科学和物理科学之间联系所不可或缺的基本问题来促进科学的进步。 这些研究活动将促进对代表性不足的少数民族学生以及嵌入研究人员实验室的高中教师的STEM培训。将进行实验以测试磁小体是否在产生MTB的代谢能量中起作用。 定制的生长室将用于在一系列外部磁场强度下培养MTB。 细菌标本将包括野生型MTB菌株和缺乏合成其内部磁体的遗传库的突变体。 磁性测量将用于确定磁小体的存在（或不存在），并表征野生型细胞中内部磁铁矿的场强。 细菌的生长和活动将通过吸光度测量，细胞计数，游泳速度和能量携带分子的测定来监测。 野生型与突变株的组学和同位素标记化合物的掺入将允许鉴定受磁场影响的基因网络和产物（蛋白质和代谢物）。 整合这些不同但互补的实验数据将允许仔细测试新的假设，即磁小体进化以最大限度地吸收能量和/或在自然界中MTB经常占据的有机碳耗尽的环境中持久。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

项目成果

Implementation of an Online Poster Symposium for a Large-Enrollment, Natural Science, General Education, Asynchronous Course

大招生自然科学通识异步课程在线海报研讨会的实施

• DOI: 10.3389/feduc.2022.906995
• 发表时间: 2022
• 期刊: Frontiers in Education
• 影响因子: 2.3
• 作者: Weaver, Ella M.;Shaul, Kylienne A.;Lower, Brian H.
• 通讯作者: Lower, Brian H.

Thermophilic Magnetotactic Bacteria from Mickey Hot Springs, an Arsenic-Rich Hydrothermal System in Oregon

• DOI: 10.1021/acsearthspacechem.1c00318
• 发表时间: 2022-02
• 期刊: ACS Earth and Space Chemistry
• 影响因子: 3.4
• 作者: Zachery Oestreicher;Lumarie Pérez‐Guzmán;Nadia N. Casillas-Ituarte;Michaela R. Hostetler;E. Mumper;D. Baz

Statistical Thermodynamic Description of Heteroaggregation between Anthropogenic Particulate Matter and Natural Particles in Aquatic Environments

• DOI: 10.1021/acsearthspacechem.0c00318
• 发表时间: 2021-03
• 期刊: ACS Earth and Space Chemistry
• 影响因子: 3.4
• 作者: R. Wheeler;S. Lower

Localization of Native Mms13 to the Magnetosome Chain of Magnetospirillum magneticum AMB-1 Using Immunogold Electron Microscopy, Immunofluorescence Microscopy and Biochemical Analysis

使用免疫金电子显微镜、免疫荧光显微镜和生化分析将天然 Mms13 定位到磁螺菌 AMB-1 的磁小体链上

• DOI: 10.3390/cryst11080874
• 发表时间: 2021
• 期刊: Crystals
• 影响因子: 2.7
• 作者: Oestreicher, Zachery;Valverde-Tercedor, Carmen;Mumper, Eric;Pérez-Guzmán, Lumarie;Casillas-Ituarte, Nadia N.;Jimenez-Lopez, Concepcion;Bazylinski, Dennis A.;Lower, Steven K.;Lower, Brian H.
• 通讯作者: Lower, Brian H.

A meta-analysis framework to assess the role of units in describing nanoparticle toxicity

评估单位在描述纳米颗粒毒性中的作用的荟萃分析框架

• DOI: 10.1016/j.impact.2020.100277
• 发表时间: 2021
• 期刊: NanoImpact
• 影响因子: 4.9
• 作者: Wheeler, Robert M.;Lower, Steven K.
• 通讯作者: Lower, Steven K.