| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | August 26, 2014 |
| Latest Amendment Date: | August 25, 2019 |
| Award Number: | 1424138 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Enriqueta Barrera
EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2014 |
| End Date: | August 31, 2020 (Estimated) |
| Total Intended Award Amount: | $282,000.00 |
| Total Awarded Amount to Date: | $392,002.00 |
| Funds Obligated to Date: |
FY 2015 = $56,395.00 FY 2018 = $53,607.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
1960 KENNY RD COLUMBUS OH US 43210-1016 (614)688-8735 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
Columbus OH US 43210-1320 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
Instrumentation & Facilities, Geobiology & Low-Temp Geochem |
| Primary Program Source: |
01001516DB NSF RESEARCH & RELATED ACTIVIT 01001819DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
There is increasing demand for magnetic nanoparticles in emerging areas of technology and medicine (e.g., high-density data storage, targeted drug delivery, scaffolding for tissue regeneration). The "ideal" particle for many of these applications is a nanometer scale magnet that has defined shape and morphology, narrow size distribution, high crystallinity, and controlled magnetic direction. Magnetotactic bacteria (MTB) have the innate capacity to synthesize crystals of the mineral magnetite (Fe3O4) that meet all of these criteria. In this proposal, investigators will study the protein-directed crystallization of magnetite by MTB.
MTB exercise strict genetic control over the size, composition, and morphology of their nanomagnetic crystals. Investigators will examine the so-called Mms proteins (Mms-5, 6, 12, 13; or homologues like MamC) to identify the key catalytic domains that direct nucleation and growth of Fe3O4. In vivo biomineralization experiments will be performed using wild-type strains (e.g., Magnetospirillum magneticum) as well as mutationally altered strains generated during this project. In vitro crystallization experiments will be carried out using recombinant proteins, or peptides that mimic key motifs. Structural and magnetic properties of the in vivo vs. in vitro mineral products will be characterized using electron microscopy, atomic force microscopy, confocal laser scanning microscopy, and magnetometry. Those proteins or peptides that catalyze novel mineral products will be further examined using molecular dynamics simulations in silico. The knowledge to be gained from these studies will allow to fabricate nanometer scale, single domain magnetic crystals that are designed to elicit a particular magnetic response.
This project also includes an educational outreach component for middle- and high-school students and teachers. Teachers will spend 3-4 weeks each year with the PIs learning how to collect and isolate MTB from environmental samples as well as characterize MTB with various forms of optical and electron microscopy. Based on this experience, the teachers will design experiments to use in their own classrooms. Investigators will also direct two field camps: an annual, domestic camp on environmental microbiology and one international field camp on biomineralization. Student participants will learn to design and test scientific hypothesis though field studies, lab experiments, and instrumental analyses (e.g., electron microscopy). The students will present their results at an annual science symposium.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Intellectual merit: Over the past six years, several research activities have advanced our work with magnetotactic bacteria resulting in 10 journal articles, 3 textbooks, 13 published abstracts, 2 book chapters, 3 post-doctoral researchers (2 underrepresented minority), 4 PhD dissertations (2 underrepresented minority), 3 MS thesis (2 underrepresented minority) and 5 BS degrees with research distinction (4 underrepresented minority). These research activities are broadly classified under two efforts: (1) biomineralization and (2) magneto-aerotaxis.
Biomineralization: The primary goal is to understand the mechanism(s) by which microorganisms use different genes, proteins and lipids to control the synthesis of minerals in the environment. Understanding how this is accomplished allows us to understand the evolution of life on Earth, enhance soil quality and fertility, develop new strategies for subsurface remediation and create drug-delivery systems, nanomineral synthesis systems and therapies for use in biotechnology and medicine. We determined how specific proteins that are synthesized by magentotatic bacteria are used to synthesize magnetic nanominerals. We developed a novel method to collect and isolate magnetotactic bacteria from the environment and used it to collect several new species of bacteria. Finally, we created an artificial system to synthesize magnetic nanominerals in a laboratory setting having well defined morphology and size.
Magneto-aerotaxis: Determining the biophysical properties of magneto-aerotaxis (i.e., bacteria swimming in response to a magnetic field and oxygen gradient) is crucial to understanding the behavior of magnetotactic bacteria and the evolution of this mode of motility. We used our ability to measure the swimming behavior of living single cells (or multiple cells) by localizing magnetotactic bacteria in microscopic magnetic traps and applying environmental stimuli (e.g., UV radiation, oxygen gradients, temperature) to observe their response in terms of swimming velocity, response time, flagellar thrust and magnetic moment. In addition, the novel technique that we developed can be easily adapted to study motility of other living bacteria. It should prove to be a useful system to study bacterial motion in a noninvasive manner because cells are free to move in any three-dimensional direction, rather than being tethered to a substrate as in other systems. Finally, it was demonstrated that clusters of magnetotactic bacteria can be directed along controlled paths under the influence of in-plane magnetic fields. This ability suggests that clusters of magnetotactic bacteria could serve as a system for manipulating microscopic objects in lab-on-a-chip devices. In this sense, magnetotactic bacteria could serve as a model organism for self-assembly processes in engineered systems by acting as a self-organized microscopic agent.
Broader impacts: Over the six years, we have focused on ten outreach activities that have advanced our broader impacts including: (1) full participation of women, persons with disabilities and underrepresented minorities in STEM; (2) creation of over 50 free STEM educational modules (lecture slides, closed-captioned lecture videos, writing assignments, quizzes, study guides) for K-12 and college teachers; (3) provided research opportunities for 12 high school students, 3 high school teachers, 5 BS students, 3 MS students, 7 PhD students, 4 post-docs, 2 staff, 3 visiting professors; (4) held 5 annual 1-week science camp for a total of 1050+ middle-school students; (5) hosted 7 annual science symposiums for a total of 5,000+ undergraduate student poster presentations; (6) provided teaching assistantship positions, workshops and training opportunities for 100+ undergraduate students majoring in K-12 education or intending to go to graduate school; (7) published 6 free open courses and 3 free open textbooks for high school and college students and teachers; (8) hosted research workshops and teaching workshops for students, staff and professors; (9) rural education efforts by teaching 17 new STEM courses at Ohio State University regional campuses to 550+ undergraduate students; and (10) increased scientific literacy and engagement of public with scientific and technology through talks, seminars and interviews.
We established a global reach with our science education efforts by offering free open-source textbooks and courses. The goal was to offer high-quality and engaging courses, anytime, anywhere access, with minimal to no cost to the public. Our open science courses (available on Apple and Canvas) and open science textbooks (available on Apple and Pressbooks) have become our most popular outreach products. Each year our courses average approximately 30,000+ student subscribers, 1,000,000+ page views, 150,000+ downloads and 100,000+ video streams. Apple named our Environmental Science course Best of 2015. Our free open textbooks were the Top 10 most popular textbooks on Apple Books for their first two years of publication. In addition, the free open textbooks have saved 14,000+ Ohio State University (OSU) students $700,000+ in the past six years. We have increased scientific literacy at OSU by targeting our course for both STEM and non-STEM majors. Enrollment in our General Education Natural Science courses has increased to 2,300 students per year at OSU, with over 50% of the students earning non-STEM degrees.
Last Modified: 12/18/2020
Modified by: Brian H Lower
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