Ocean sediments consist mainly of calcium carbonate and organic matter (phytoplankton debris). Once subducted, some carbon is removed from the slab and returns to the atmosphere as CO in arc magmas. Its isotopic signature is thought to reflect the bulk fraction of inorganic (carbonate) and organic (graphitic) carbon in the sedimentary source. Here we challenge this assumption by experimentally investigating model sediments composed of C-CaCO + C-graphite interacting with water at pressure, temperature and redox conditions of an average slab-mantle interface beneath arcs. We show that oxidative dissolution of graphite is the main process controlling the production of CO, and its isotopic composition reflects the CO/CaCO rather than the bulk graphite/CaCO (i.e., organic/inorganic carbon) fraction. We provide a mathematical model to relate the arc CO isotopic signature with the fluid-rock ratios and the redox state in force in its subarc source.
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http://dx.doi.org/10.1038/s41467-022-30421-5 | DOI Listing |
Phys Chem Chem Phys
January 2025
Université Paris Cité, CNRS, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, 75005, Paris, France.
Tetramethylammonium (TMA) is a ubiquitous cationic motif in biochemistry, found in the charged choline headgroup of membrane phospholipids and in tri-methylated lysine residues, which modulates histone-DNA interactions and impacts epigenetic mechanisms. TMA interactions with anionic species, particularly carboxylate groups of amino acid residues and extracellular sugars, are of substantial biological relevance, as these interactions mediate a wide range of cellular processes. This study investigates the molecular interactions between TMA and acetate, representing carboxylate-containing groups, using neutron scattering experiments complemented by force fields and molecular dynamics (MD) simulations.
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA.
Complexins are a family of small presynaptic proteins that regulate neurotransmitter release at nerve terminals and are highly conserved in evolution. While direct interactions with SNARE proteins are critical for all complexin functions, binding of their disordered C-terminal domains (CTD) to membranes, especially to synaptic vesicle membranes, is essential for the ability of complexin to inhibit vesicle release. Furthermore, while some complexin CTDs possess an endogenous affinity for membranes, other complexin isoforms are subject to lipidation at their C-termini, which is presumed to confer additional membrane binding.
View Article and Find Full Text PDFEcotoxicology
January 2025
Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mazatlán, Sinaloa, México.
Monitoring the dynamics of contaminants in ecosystems helps understand their potential effects. Seabirds have been used as biomonitors of marine ecosystems for this purpose. However, exposure and vulnerability to pollutants are understudied in tropical species, and the relationships between various pollutants and the trophic ecology of seabirds are poorly understood.
View Article and Find Full Text PDFChemMedChem
January 2025
National Institute of Standards and Technology, Material Measurement Laboratory, UNITED STATES OF AMERICA.
Antibody-based pharmaceuticals are the leading biologic drug platform (> $75B/year). Despite a wealth of information collected on them, there is still a lack of knowledge on their inter-domain structural distributions, which impedes innovation and development. To address this measurement gap, we have developed a new methodology to derive biomolecular structure ensembles from distance distribution measurements via a library of tagged proteins bound to an unlabeled and otherwise unmodified target biologic.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Department of Ecology and Coastal Management, Instituto de Ciencias Marinas de Andalucía (ICMAN-CSIC), Avda. República Saharaui, 2, Puerto Real, Cadiz, 11510, Spain; Associate Research Unit "Blue Growth", Spanish National Research Council (CSIC) - Andalusian Institute of Agricultural and Fisheries Research and Training (IFAPA), Cadiz, Spain. Electronic address:
The variability in trophic position and carbon isotopic signatures can provide information about their dietary flexibility and its ability to adapt to changing environmental conditions. The impact of the invasive blue crab Callinectes sapidus was assessed by estimating its trophic position and isotopic niche using stable isotopes (δ³C, δ⁵N, δ³⁴S) across different invaded Atlantic coastal areas. This study, the first of its kind in the eastern Atlantic range, reveals the crab's omnivorous behavior with a wide trophic position (TP = 2-4), consistent with findings from its native range.
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