The absolute concentration and the compartmentalization of analytes in cells and organelles are crucial parameters in the development of drugs and drug delivery systems, as well as in the fundamental understanding of many cellular processes. Nanoscale secondary ion mass spectrometry (NanoSIMS) imaging is a powerful technique which allows subcellular localization of chemical species with high spatial and mass resolution, and high sensitivity. In this study, we combined NanoSIMS imaging with spatial oversampling with transmission electron microscopy (TEM) imaging to discern the compartments (dense core and halo) of large dense core vesicles in a model cell line used to study exocytosis, and to localize C dopamine enrichment following 4-6 h of 150 μM C L-3,4-dihydroxyphenylalanine (L-DOPA) incubation. In addition, the absolute concentrations of C dopamine in distinct vesicle domains as well as in entire single vesicles were quantified and validated by comparison to electrochemical data. We found concentrations of 87.5 mM, 16.0 mM and 39.5 mM for the dense core, halo and the whole vesicle, respectively. This approach adds to the potential of using combined TEM and NanoSIMS imaging to perform absolute quantification and directly measure the individual contents of nanometer-scale organelles.
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http://dx.doi.org/10.3390/ijms23010160 | DOI Listing |
Sci Rep
October 2024
Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.
J Am Chem Soc
July 2024
Department of Chemistry, The University of Hong Kong, Pok Fu Lam, Hong Kong 999077, P. R. China.
Nanoscale secondary ion mass spectrometry (NanoSIMS) makes it possible to visualize elements and isotopes in a wide range of samples at a high resolution. However, the fidelity and quality of NanoSIMS images often suffer from distortions because of a requirement to acquire and integrate multiple image frames. We developed an optical flow-based algorithm tool, NanoSIMS Stabilizer, for all-channel postacquisition registration of images.
View Article and Find Full Text PDFBioconjug Chem
July 2024
Medicinal Chemistry, Research and Development, Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, SE-431 83 Gothenburg, Sweden.
Extensive efforts have been dedicated to developing cell-specific targeting ligands that can be conjugated to therapeutic cargo, offering a promising yet still challenging strategy to deliver oligonucleotide therapeutics beyond the liver. Indeed, while the cargo and the ligand are crucial, the third component, the linker, is integral but is often overlooked. Here, we present strain-promoted sydnone-alkyne cycloaddition as a versatile linker chemistry for oligonucleotide synthesis, expanding the choices for bioconjugation of therapeutics while enabling subcellular detection of the linker and payload using nanoscale secondary ion mass spectrometry (NanoSIMS) imaging.
View Article and Find Full Text PDFEnviron Pollut
August 2024
Department of Isotope Biochemistry, Currently Merged As Department of Technical Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, 04318, Leipzig, Germany; Department of Biology, Section for Microbiology, Aarhus University, 8000, Aarhus C, Denmark. Electronic address:
The presence and accumulation of both, plastics and antibiotics in soils may lead to the colonization, selection, and propagation of soil bacteria with certain metabolic traits, e.g., antibiotic resistance, in the plastisphere.
View Article and Find Full Text PDFProtein turnover is a critical process for accurate cellular function, in which damaged proteins in the cells are gradually replaced with newly synthesized ones. Many previous studies on cellular protein turnover have used stable isotopic labelling by amino acids in cell culture (SILAC), followed by proteomic bulk analysis. However, this approach does not take into account the heterogeneity observed at the single-cell and subcellular levels.
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