The fusion of cells by influenza hemagglutinin (HA) is the best characterized example of protein-mediated membrane fusion. In simultaneous measurements of pairs of assays for fusion, we determined the order of detectable events during fusion. Fusion pore formation in HA-triggered cell-cell fusion was first detected by changes in cell membrane capacitance, next by a flux of fluorescent lipid, and finally by flux of aqueous fluorescent dye. Fusion pore conductance increased by small steps. A retardation of lipid and aqueous dyes occurred during fusion pore fluctuations. The flux of aqueous dye depended on the size of the molecule. The lack of movement of aqueous dyes while total fusion pore conductance increased suggests that initial HA-triggered fusion events are characterized by the opening of multiple small pores: the formation of a "sieve".
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http://dx.doi.org/10.1083/jcb.127.6.1885 | DOI Listing |
Methods Mol Biol
January 2025
Institute of Physical Chemistry, University of Göttingen, Göttingen, Germany.
We present two innovative approaches to investigate the dynamics of membrane fusion and the strength of protein-membrane interactions. The first approach employs pore-spanning membranes (PSMs), which allow for the observation of protein-assisted fusion processes. The second approach utilizes colloidal probe microscopy with membrane-coated probes with reconstituted proteins.
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Department of Immunobiology, University of Lausanne, Epalinges, Switzerland.
Fluorescence recovery after photobleaching (FRAP) can be employed to investigate membrane lipid mixing of vacuoles in live budding yeast cells and distinguish the fused, hemi-fused or non-fused states of these organelles under physiological conditions. Here, we describe a protocol for labeling the outer and inner leaflets of vacuoles in live cells that allow to detect hemifusion intermediates and, thus, identify components necessary for fusion pore opening.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Ulsan National Institute of Science and Technology, Department of Chemistry, UNIST GIL 50, 44919, Ulsan, KOREA, REPUBLIC OF.
Efficient separation of hydrogen isotopes, especially deuterium (D2), is pivotal for advancing industries such as nuclear fusion, semiconductor processing, and metabolic imaging. Current technologies, including cryogenic distillation and Girdler sulfide processes, suffer from significant limitations in selectivity and cost-effectiveness. Herein, we introduce a novel approach utilizing an imidazolium-based Metal-Organic Framework (MOF), JCM-1, designed to enhance D2/H2 separation through temperature-dependent gate-opening controlled by ion exchange.
View Article and Find Full Text PDFEcotoxicol Environ Saf
January 2025
College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Harbin 150030, China. Electronic address:
Bisphenol A (BPA) is a common endocrine disruptor chemical that is widely used in the production of food plastic packaging, and it has been shown to potentially harm the reproductive system. However, the specific mechanism by which BPA induces apoptosis of Leydig cells (LCs) and inhibits testosterone synthesis in these cells is unclear. In the present study, TM3 cells were used as an experimental model in combination with a reactive oxygen species (ROS) scavenger (N-acetylcysteine), Caspase-3 inhibitor (Ac-DEVD-CHO), autophagy activator (Torin2), and autophagy inhibitor (Chloroquine) to investigate the potential mechanisms by which BPA causes TM3 cell damage in vitro.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Department of Industrial Engineering, University of Trento, 38123 Trento, Italy.
The metastable β-Ti21S alloy exhibits a lower elastic modulus than Ti-6Al-4V ELI while maintaining high mechanical strength and ductility. To address stress shielding, this study explores the integration of lattice structures within prosthetics, which is made possible through additive manufacturing. Continuous adhesion between the implant and bone is essential; therefore, auxetic bow-tie structures with a negative Poisson's ratio are proposed for regions under tensile stress, while Triply Periodic Minimal Surface (TPMS) structures with a positive Poisson's ratio are recommended for areas under compressive stress.
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