Dynamics of a vesicle under simple shear flow is studied in the limit of small capillary number. A perturbative approach is used to derive the equation of vesicle dynamics. The expansions are shown to converge for significantly deflated vesicles (with excess area from the sphere as high as 2). In particular, we provide an explicit analytical expression for the tank-treading to tumbling bifurcation point. This expression is valid for excess areas up to 2.5. The results are compared with full 3D numerical simulations. The proposed method can be used for analytical or numerical solution of vesicle dynamics under weak flow of general form.
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http://dx.doi.org/10.1103/PhysRevE.85.061922 | DOI Listing |
FEBS Open Bio
January 2025
Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Germany.
Neurotransmitter release is triggered in microseconds by the two C domains of the Ca sensor synaptotagmin-1 and by SNARE complexes, which form four-helix bundles that bridge the vesicle and plasma membranes. The synaptotagmin-1 CB domain binds to the SNARE complex via a 'primary interface', but the mechanism that couples Ca-sensing to membrane fusion is unknown. Widespread models postulate that the synaptotagmin-1 Ca-binding loops accelerate membrane fusion by inducing membrane curvature, perturbing lipid bilayers or helping bridge the membranes, but these models do not seem compatible with SNARE binding through the primary interface, which orients the Ca-binding loops away from the fusion site.
View Article and Find Full Text PDFSci China Life Sci
January 2025
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China.
Mitochondrial Rho-GTPase 1 (MIRO1) is an outer mitochondrial membrane protein which regulates mitochondrial transport and mitophagy in mitosis. In present study, we reported the crucial roles of MIRO1 in mammalian oocyte meiosis and its potential relationship with aging. We found that MIRO1 expressed in mouse and porcine oocytes, and its expression decreased in aged mice.
View Article and Find Full Text PDFMol Biol Rep
January 2025
Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
Background: Exosomes are extracellular vesicles released by cells that mediate intercellular communication and actively participate in cancer progression, metastasis, and regulation of immune response within the tumour microenvironment. Inhibiting exosome release from cancer cells could be employed as a therapeutic against cancer.
Methods And Results: In the present study, we have studied the effects of Acorus calamus in inhibiting exosome secretion via targetting Rab27a and neutral sphingomyelinase 2 (nSMase2) in HER2-positive (MDA-MB-453), hormone receptor-positive (MCF-7) and triple-negative breast cancer (MDA-MB-231) cells.
Cell Death Dis
January 2025
School of Pharmacy, Faculty of Medicine & State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, China.
Small extracellular vesicles (sEVs), carrying PD-L1, have been implicated in immune evasion and tumor progression. However, understanding how PD-L1 sEVs are secreted still needs to be improved. We found that the secretion dynamics of PD-L1 sEVs is similar to that of other sEVs.
View Article and Find Full Text PDFJ Exp Bot
January 2025
Vegetable and Fruit Improvement Center and Department of Horticultural Sciences Texas A&M University, College Station, TX 77843, USA.
Complex N-glycans are asparagine (N)-linked branched sugar chains attached to secretory proteins in eukaryotes. They are produced by modification of N-linked oligosaccharide structures in the endoplasmic reticulum (ER) and Golgi apparatus. Complex N-glycans formed in the Golgi apparatus are often assigned specific roles unique to the host organism, with their roles in plants remaining largely unknown.
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