Exocytic fusion in neuroendocrine cells does not always result in complete release of the peptide contents from dense core vesicles (DCVs). In this study, we use fluorescence imaging and immunoelectron microscopy to examine the retention, endocytosis and recycling of chromogranin B in DCVs of NGF-treated PC12 cells. Our results indicate that DCVs retained and retrieved an intact core that was available for subsequent exocytic release. The endocytic process was inhibited by cyclosporine A or by substitution of extracellular Ca(2+) with Ba(2+) and the total recycling time was less than 5 min.
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http://dx.doi.org/10.1016/j.febslet.2004.05.086 | DOI Listing |
ACS Nano
December 2024
Department of Chemistry, University of California, Berkeley, California 94720, United States.
Characterizing the size, structure, and composition of nanoparticles is vital in predicting and understanding their macroscopic properties. In this work, charge detection mass spectrometry (CDMS) was used to analyze nanocapsules (∼10-200 MDa) consisting of a liquid oleic acid core surrounded by a dense silica outer shell. CDMS is an emerging method for nanoparticle analysis that can rapidly measure the mass and charge of thousands of individual nanoparticles.
View Article and Find Full Text PDFHuan Jing Ke Xue
January 2025
Institute of Blue and Green Development, Shandong University, Weihai 264209, China.
Clarifying the spatial correlation network structure from tourism transportation carbon emissions and its influencing factors is crucial for China's tourism and transportation industry to coordinate the planning of carbon reduction governance and realize the sustainable development of the tourism transportation industry. Based on inter-provincial panel data from 2001 to 2021, China's carbon emissions from tourism transportation were measured, and the modified spatial gravity model was used to construct characteristics of provincial spatial networks and their influencing factors, which were analyzed using the social network analysis method and the QAP model. The study showed that ① China's total carbon emissions from tourism and transportation have been growing slowly year by year, showing a distribution pattern of "high in the southeast and low in the northwest," with obvious differences between the eastern and western regions.
View Article and Find Full Text PDFBiochem Biophys Res Commun
December 2024
Graduate School of Chemical Sciences and Engineering, Hokkaido University, N13, W8, Sapporo, 060-8628, Japan; Department of Chemistry, Faculty of Science, Hokkaido University, N8, W5, Sapporo, 060-0810, Japan. Electronic address:
Bicelles, an artificial disk-shaped lipid bilayer, are commonly used for the structural and functional characterization of membrane-bound proteins in an environment similar to that in intracellular membranes. Because the dynamics of the lipids that constitute bicelles exert a significant impact on the structure and function of the inserted proteins, we investigated the mobility of lipid molecules in bicelles composed of DMPC (14:0 PC) and DHPC (06:0 PC) using solution NMR and MD calculations. C R relaxation experiments for the acyl groups demonstrated that increasing bicelle sizes limit the rotational diffusion of acyl chain H-C bonds in DMPC.
View Article and Find Full Text PDFBiophys J
December 2024
Cellular and Molecular Physiology, School of Medicine, Yale University, New Haven, CT; Nanobiology Institute, Yale University, West Haven, CT; Molecular Biophysics and Biochemistry, Yale University, New Haven, CT; Saints-Pères Paris Institute for the Neurosciences (SPPIN), Université de Paris, Centre National de la Recherche Scientifique (CNRS) UMR 8003, Paris, France; Wu Tsai Institute, Yale University. Electronic address:
Synaptotagmin-1 (Syt1) is a major calcium sensor for rapid neurotransmitter release in neurons and hormone release in many neuroendocrine cells. It possesses two tandem cytosolic C2 domains that bind calcium, negatively charged phospholipids, and the neuronal SNARE complex. Calcium binding to Syt1 triggers exocytosis, but how this occurs is not well understood.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
Semenov Federal Research Center for Chemical Physics, Kosygina, 4, 119991 Moscow, Russia.
The ability of particles to transform absorbed energy into translational movements brings peculiar order into nonequilibrium matter. Connected together into a chain, these particles collectively behave completely differently from well-known equilibrium polymers. Examples of such systems vary from nanoscale to macroscopic objects.
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