Biogeochemical fingerprinting of magnetotactic bacterial magnetite
Bazylinski, Dennis A.
Iowa State University Digital Repository, Ames IA (United States)
Is Version Of
Ames National Laboratory
Biominerals are important archives of the presence of life and environmental processes in the geological record. However, ascribing a clear biogenic nature to minerals with nanometer-sized dimensions has proven challenging. Identifying hallmark features of biologically controlled mineralization is particularly important for the case of magnetite crystals, resembling those produced by magnetotactic bacteria (MTB), which have been used as evidence of early prokaryotic life on Earth and in meteorites. We show here that magnetite produced by MTB displays a clear coupled C–N signal that is absent in abiogenic and/or biomimetic (protein-mediated) nanometer-sized magnetite. We attribute the presence of this signal to intracrystalline organic components associated with proteins involved in magnetosome formation by MTB. These results demonstrate that we can assign a biogenic origin to nanometer-sized magnetite crystals, and potentially other biominerals of similar dimensions, using unique geochemical signatures directly measured at the nanoscale. This finding is significant for searching for the earliest presence of life in the Earth’s geological record and prokaryotic life on other planets.
This is a manuscript of an article published as Pérez-Huerta, Alberto, Chiara Cappelli, Ylenia Jabalera, Tanya Prozorov, Concepcion Jimenez-Lopez, and Dennis A. Bazylinski. "Biogeochemical fingerprinting of magnetotactic bacterial magnetite." Proceedings of the National Academy of Sciences 119, no. 31 (2022): e2203758119. DOI: 10.1073/pnas.2203758119. Copyright 2022 The Author(s). Posted with permission. DOE Contract Number(s): AC02-07CH11358; EAR-1647012; EAR-150779; EAR-1423939.