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Mumper Final Dissertation.pdf (2.7 MB)

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Mixotrophic Magnetosome-Dependent Magnetoautotrophic Metabolism of Model Magnetototactic Bacterium Magnetospirillum magneticum AMB-1

Mumper, Eric Keith
http://orcid.org/0000-0003-3019-446X
http://rave.ohiolink.edu/etdc/view?acc_num=osu1551880645784717

Abstract Details

2019, Doctor of Philosophy, Ohio State University, Earth Sciences.
Magnetospirillum magneticum AMB-1 is a member of a phylogenetically diverse group of bacteria characterized by their ability to biomineralize magnetic minerals known collectively as magnetotactic bacteria (MTB). MTB produce chains of membrane-bound intracellular magnetic nanocrystals, collectively known as magnetosomes. The current scientific consensus is that magnetosomes are used by MTB to orient themselves in vertically stratified water columns in order to achieve optimal oxygen concentrations in a process known as magnetoaerotaxis. Biomineralization of magnetosomes is an energy intensive process which accounts for roughly 33% of the cell's metabolic budget. This high metabolic cost seems to contradict with the amount of time MTB cells spend aligned with external magnetic fields. Due to this apparent discrepancy, I examined the potential role the magnetosome may play in bacterial metabolism. Through analysis of comparative growth on a variety of media compositions both magnetic, wild type and non-magnetic, mutant strains of AMB-1, I discovered that cells grown under stress conditions exhibit an inversion of growth dynamics which indicates some advantage for magnetic cells. Non-magnetic, mutant cells display a direct relationship between external magnetic field strength and growth, indicating magnetic field dependence. I believe that this represents a novel magnetosome-dependant mixotrophic metabolism. Due to the ubiquity of MTB and the diversity of sessile eukaryotes which either produce biogenic magnetite or exhibit magnetosensing, this system may be part of a widespread, previously unknown component of global carbon cycling.
Steven Lower (Advisor)
Brian Lower (Committee Member)
Ratnasingham Sooryakumar (Committee Member)
Ann Cook (Committee Member)
129 p.
Biogeochemistry; Geobiology; Geology; Microbiology; Mineralogy
Geomicrobiology, biomineralization, magnetotactic bacteria, biochemistry, magnetotaxis, microbiology, geochemistry, Magnetospirillum, magneticum, AMB-1, magnetotactic, biogenic magnetite, magnetic, cryptochrome, magnetoreception, biogeochemistry

Recommended Citations

Citations

  • Mumper, E. K. (2019). Mixotrophic Magnetosome-Dependent Magnetoautotrophic Metabolism of Model Magnetototactic Bacterium Magnetospirillum magneticum AMB-1 [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1551880645784717

    APA Style (7th edition)

  • Mumper, Eric. Mixotrophic Magnetosome-Dependent Magnetoautotrophic Metabolism of Model Magnetototactic Bacterium Magnetospirillum magneticum AMB-1. 2019. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1551880645784717.

    MLA Style (8th edition)

  • Mumper, Eric. "Mixotrophic Magnetosome-Dependent Magnetoautotrophic Metabolism of Model Magnetototactic Bacterium Magnetospirillum magneticum AMB-1." Doctoral dissertation, Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1551880645784717

    Chicago Manual of Style (17th edition)

osu1551880645784717
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© 2019, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.