2025 Hyper Recent •CC0 1.0 Universal

This work is dedicated to the public domain. No rights reserved.

Access Preprint From Server
March 31st, 2025
Version: 1
Ben Gurion University
biochemistry
biorxiv

Integrated Approach to Investigate Magnetite Cycle in Marine Methanic Sediments

Rivlin, A.Open in Google Scholar•Bosco, A.Open in Google Scholar•Boyko, V.Open in Google Scholar•Shaar, R.Open in Google Scholar•Zemach, Y.Open in Google Scholar•Herut, B.Open in Google Scholar•Henkel, S.Open in Google Scholar•Weiss-Sarusi, K.Open in Google Scholar•Sivan, O.Open in Google Scholar

Magnetite (Fe3O4), a ubiquitous sedimentary iron mineral, is crucial for paleomagnetic records preservation. However, reactive ferric iron minerals, including magnetite, can undergo reduction in aquatic sediments above and within the sulfidic zone and at the Sulfate-Methane Transition Zone (SMTZ), resulting in the production of dissolved ferrous iron. Partial reoxidation of the reduced iron at the oxic-anoxic interface can lead to authigenic magnetite precipitation. Yet, magnetite persistence and behavior in deeper methanic sediments have remained poorly understood. Here we explore magnetite dynamics in different sub- methanic zones (deeper, middle and upper) of Mediterranean continental shelf sediments, including the potential for its authigenic precipitation. Sequential extractions revealed increasing magnetite concentrations accompanied by low-temperature magnetization (Verwey transition). First-order reversal curve (FORC) analyses supported nanoscale authigenic magnetite presence. The results highlight a net increase in single-domain magnetite in the middle methanic zone with declines in the upper and deeper zones. Microbial analyses pointed to iron reduction throughout the methanic zone, alongside potential precipitation of magnetite and a decline in methanogenesis functional genes. Sediment incubations with spiked 57Fe-ferrihydrite showed gross precipitation of isotopically enriched 57Fe-magnetite in the upper methanic zone. Our combined findings distinguish between gross and net magnetite precipitation, suggesting authigenic magnetite formation within the methanic zone, with reshaping and smoothing of the original magnetic signal. They also emphasize the limitations of relying on a single-method approach to unravel such complex processes. We propose that the methanic zone plays a critical role in the early diagenesis of magnetic minerals, driven by dynamic cycles of magnetite dissolution and authigenic precipitation.

Similar Papers

biorxiv
Wed Apr 02 2025
In vivo activation of the dia BGC allows consolidation of the biosynthetic pathways of diaporthin, dichlorodiaporthin, diaporthinic acid, and diaporthinol
Fungal secondary metabolites exhibit remarkable chemical diversity and biological activity, making them valuable sources of bioactive compounds. A group of polyketides, with a similar core structure, have been isolated previously from different fungi - the phytotoxins diaporthin and orthosporin, the mediocre antimicrobial dichlorodiaporthin, as well as diaporthinol and diaporthinic acid. Previous ...
Burger, I.
•
Leonhartsberger, S.
•
Peikert, K.
•
Fourtis, L.
...•
Zimmermann, C.
biorxiv
Wed Apr 02 2025
Theory on the accurate estimation of Michaelis-Menten enzyme kinetic parameters from steady state and progress curve datasets
Accurate estimation of enzyme kinetic parameters such as KM and vmax from the experimental datasets is critical to characterize any enzyme. The validity of widely used standard quasi steady state approximation over decades relies on a priori information of KM and other kinetic parameters which are generally not available for newly identified enzyme systems. Progress curve analysis of the time cour...
Murugan, R.
biorxiv
Wed Apr 02 2025
Development of a Vibrio natriegens-based plate-clearing assay for rapid screening of PET-hydrolyzing enzymes
Polyethylene terephthalate (PET) is a major contributor to plastic waste. Enzymatic PET degradation offers a sustainable recycling approach, but screening for effective enzymes remains challenging. Herein, we established an experimental plate-clearing assay with Vibrio natriegens, exploiting its protein-secretion ability to rapidly identify catalytic activity without time-consuming downstream proc...
Bolstad, I. M.
•
Trooyen, S. H.
•
Luciano, D.
•
Petersen, E.
•
Courtade, G.
biorxiv
Wed Apr 02 2025
Baseline bioenergetic profile of mitochondria and permeabilized tissue of Aedes aegypti (Diptera: Culicidae) throughout its life cycle
Cellular respiration parameters provide information on the energy metabolism of an organism under physiological or non-conditions and can be determined by isolating mitochondria or even using their permeabilized tissue. The present study aimed to describe the mitochondrial activity of Ae. aegypti throughout its life cycle. For this purpose, we isolated mitochondria and permeabilized tissue (1 and ...
Castillo-Morales, R. M.
•
Urbina-Duitama, D. L.
•
Mendez, S. C.
•
Duque, J. E.
biorxiv
Wed Apr 02 2025
Customizing the Structure of a Minimal TIM Barrel to Craft a De Novo Enzyme
The TIM barrel is the most prevalent fold in natural enzymes, supporting efficient catalysis of diverse chemical reactions. While de novo TIM barrels have been successfully designed, their minimalistic architectures lack structural elements essential for substrate binding and catalysis. Here, we present CANVAS, a computational workflow that introduces a structural lid into a minimal de novo TIM ba...
Beck, J.
•
Smith, B. J.
•
Zarifi, N.
•
Freund, E.
...•
Hoecker, B.
biorxiv
Wed Apr 02 2025
Phosphate-binding pocket on cyclin B governs CDK substrate phosphorylation and mitotic timing
Cell cycle progression is governed by complexes of the cyclin-dependent kinases (CDKs) and their regulatory subunits cyclin and Cks1. CDKs phosphorylate hundreds of substrates, often at multiple sites. Multisite phosphorylation depends on Cks1, which binds initial priming phosphorylation sites to promote secondary phosphorylation at other sites. Here, we describe a similar role for a recently disc...
Ng, H. Y.
•
Whelpley, D. H.
•
Adly, A. N.
•
Maxwell, R. A.
•
Morgan, D. O.
biorxiv
Wed Apr 02 2025
Specific binding modes of SIRT6 C-terminal domain to the nucleosome core particle influence DNA unwrapping and H3K27 accessibility
Sirtuins are a class of NAD-dependent histone deacetylases that regulate important biological pathways in prokaryotes and eukaryotes. This enzyme family comprises seven members, named SIRT1 to SIRT7. Among them, Sirtuin 6 (SIRT6) is a human sirtuin that deacetylates histones and plays a key role in DNA repair, telomere maintenance, carbohydrate and lipid metabolism, and lifespan. SIRT6\'s structur...
Qiu, Y.
•
Papai, G.
•
Ben Shem, A.
•
Bignon, E.
biorxiv
Wed Apr 02 2025
Bayesian analysis and efficient algorithms for single-molecule fluorescence data and step counting
With the growing adoption of single-molecule fluorescence experiments, there is an increasing demand for efficient statistical methodologies and accurate analysis of the acquired measurements. Existing analysis frameworks, such as those that use kinetic models, often rely on strong assumptions on the dynamics of the molecules and fluorophores under study that render them inappropriate for general ...
Mattamira, C.
•
Ward, A.
•
Krishnan, S. T.
•
Lamichhane, R.
...•
Sgouralis, I.
biorxiv
Wed Apr 02 2025
The bacterial chaperone CsgC inhibits functional amyloid CsgA formation by promoting the intrinsically disordered pre-nuclear state
E. coli secretes a functional amyloid called curli during biofilm formation. Curli fibers are composed of polymers of the CsgA protein, which adopts a beta-sheet rich fold upon fibrillization. A chaperone-like protein called CsgC inhibits CsgA amyloid formation. Like other amyloidogenic proteins, CsgA undergoes a 3-stage aggregation process: an initial lag phase where a beta-rich nucleus forms, an...
Balistreri, A.
•
Kolli, D.
•
Jayaweera, S. W.
•
Lundahl, D.
...•
Chapman, M. R.
biorxiv
Wed Apr 02 2025
Discovery and chemical optimisation of a Potent, Bi-cyclic (Bicycle(R)) Antimicrobial Inhibitor of Escherichia coli PBP3
Penicillin binding proteins (PBPs) are well validated antimicrobial targets, but the prevalence of {beta}-lactamase driven resistance and, more rarely, target-based mutations, necessitates new classes of PBP-targeting drugs. Here we describe the discovery and optimisation of novel, bicyclic peptide (Bicycle(R)) inhibitors of E. coli PBP3 (EcPBP3) using a proprietary phage display platform, and the...
Rowland, C. E.
•
Newman, H.
•
Martin, T. T.
•
Dods, R.
...•
Dawson, M. J.