The oldest putative fossils occur as hematite filaments and tubes in jasper-carbonate banded iron formations from the 4280- to 3750-Ma Nuvvuagittuq Supracrustal Belt, Québec. If biological in origin, these filaments might have affinities with modern descendants; however, if abiotic, they could indicate complex prebiotic forms on early Earth. Here, we report images of centimeter-size, autochthonous hematite filaments that are pectinate-branching, parallel-aligned, undulated, and containing Fe-oxides. These microstructures are considered microfossils because of their mineral associations and resemblance to younger microfossils, modern Fe-bacteria from hydrothermal environments, and the experimental products of heated Fe-oxidizing bacteria. Additional clusters of irregular hematite ellipsoids could reflect abiotic processes of silicification, producing similar structures and thus yielding an uncertain origin. Millimeter-sized chalcopyrite grains within the jasper-carbonate rocks have S- and S-enrichments consistent with microbial S-disproportionation and an O-poor atmosphere. Collectively, the observations suggest a diverse microbial ecosystem on the primordial Earth that may be common on other planetary bodies, including Mars.
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http://dx.doi.org/10.1126/sciadv.abm2296 | DOI Listing |
Int J Mol Sci
November 2024
Department of Biotechnology, Institute of Biological Sciences, University of Zielona Gora, Prof. Z. Szafrana 1, 65-516 Zielona Gora, Poland.
Owing to recent advancements in nanotechnology, magnetic iron oxide nanoparticles (MNPs), particularly magnetite (FeO) and maghemite (γ-FeO), are currently widely employed in the field of medicine. These MNPs, characterized by their large specific surface area, potential for diverse functionalization, and magnetic properties, have found application in various medical domains, including tumor imaging (MRI), radiolabelling, internal radiotherapy, hyperthermia, gene therapy, drug delivery, and theranostics. However, ensuring the non-toxicity of MNPs when employed in medical practices is paramount.
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May 2024
Department of Microbiology, University of Massachusetts Amherst, Amherst, Massachusetts, USA.
Unlabelled: Extracellular cytochrome filaments are proposed to serve as conduits for long-range extracellular electron transfer. The primary functional physiological evidence has been the reported inhibition of Fe(III) oxide reduction when the gene for the filament-forming cytochrome OmcS is deleted. Here we report that the OmcS-deficient strain from that original report reduces Fe(III) oxide as well as the wild-type, as does a triple mutant in which the genes for the other known filament-forming cytochromes were also deleted.
View Article and Find Full Text PDFSmall
February 2023
Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China.
Active tether and transportation of cargoes on cytoskeletal highway enabled by molecular motors is key for accurate delivery of vesicles and organelles in the complex intracellular environment. Here, a hybrid system composed of colloidal motors and self-assembled lipid tubes is designed to mimic the subcellular traffic system in living cells. The colloidal motors, composed of gold-coated hematite, display light-activated self-propulsion tunable by the light intensity and the concentration of hydrogen peroxide fuel.
View Article and Find Full Text PDFSci Adv
April 2022
School of Earth and Environment, University of Leeds, Leeds, UK.
The oldest putative fossils occur as hematite filaments and tubes in jasper-carbonate banded iron formations from the 4280- to 3750-Ma Nuvvuagittuq Supracrustal Belt, Québec. If biological in origin, these filaments might have affinities with modern descendants; however, if abiotic, they could indicate complex prebiotic forms on early Earth. Here, we report images of centimeter-size, autochthonous hematite filaments that are pectinate-branching, parallel-aligned, undulated, and containing Fe-oxides.
View Article and Find Full Text PDFSci Rep
May 2020
Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Av. Giuseppe Maximo Scolfaro, 10000, 13083-100, Campinas, Brazil.
Precambrian cellular remains frequently have simple morphologies, micrometric dimensions and are poorly preserved, imposing severe analytical and interpretational challenges, especially for irrefutable attestations of biogenicity. The 1.88 Ga Gunflint biota is a Precambrian microfossil assemblage with different types and qualities of preservation across its numerous geological localities and provides important insights into the Proterozoic biosphere and taphonomic processes.
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