We present a novel imaging system combining total internal reflection fluorescence (TIRF) microscopy with measurement of steady-state acceptor fluorescence anisotropy in order to perform live cell Förster Resonance Energy Transfer (FRET) imaging at the plasma membrane. We compare directly the imaging performance of fluorescence anisotropy resolved TIRF with epifluorescence illumination. The use of high numerical aperture objective for TIRF required correction for induced depolarization factors. This arrangement enabled visualisation of conformational changes of a Raichu-Cdc42 FRET biosensor by measurement of intramolecular FRET between eGFP and mRFP1. Higher activity of the probe was found at the cell plasma membrane compared to intracellularly. Imaging fluorescence anisotropy in TIRF allowed clear differentiation of the Raichu-Cdc42 biosensor from negative control mutants. Finally, inhibition of Cdc42 was imaged dynamically in live cells, where we show temporal changes of the activity of the Raichu-Cdc42 biosensor.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4215982 | PMC |
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0110695 | PLOS |
J Mol Biol
January 2025
Department of Applied Bioscience, Kanazawa Institute of Technology. Electronic address:
A variety of potential biological roles of mechanical forces have been proposed in the field of cell biology. In particular, mechanical forces alter the mechanical conditions within cells and their environment, exerting a strong effect on the reorganization of the actin cytoskeleton. Single-molecule imaging studies have provided evidence that an actin filament may act as a mechanosensor.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Physics, Assam University, Silchar-788011, India.
Density functional theory has been employed to study indolo[3,2,1-]carbazole donor-based dyes, incorporating one and two units of 2,4-dimethoxybenzene auxiliary donors. Electrostatic potential analysis highlights the dye with one auxiliary donor (D2) as having the highest charge-donating capability. Structural analysis shows that auxiliary donors enhance planarity, reduce steric hindrance, and improve π-conjugation.
View Article and Find Full Text PDFAnal Chem
January 2025
Laboratoire d'Innovation Thérapeutique, UMR7200 CNRS, Université de Strasbourg, Institut du Médicament de Strasbourg, 74 route du Rhin, Strasbourg F-67000, France.
The worldwide spread of antibiotic resistance is considered to be one of the major health threats to society. While developing new antibiotics is crucial, there is also a strong need for next-generation analytical methods for studying the physiological state of live bacteria in heterogeneous populations and their response to environmental stress. Here we report a single-cell high-throughput method to monitor changes in the bacterial cell envelope in response to stress based on ratiometric flow cytometry.
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Neurological Disorders Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar.
Vesicle fusion induces neurotransmitter release, orchestrated by synaptotagmin-1 (Syt-1) as a Ca sensor. However, the precise molecular mechanisms of Syt-1 remain controversial, with various and competing models proposed based on different ionic strengths. Syt-1, residing on the vesicle membrane alongside anionic phospholipids such as phosphatidylserine (PS), undergoes Ca-induced binding to its own vesicle membrane, known as the cis-interaction, which prevents the trans-interaction of Syt-1 with the plasma membrane.
View Article and Find Full Text PDFGene
January 2025
Department of Pediatrics, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China. Electronic address:
Background: Methyltransferase-like 3 (METTL3) regulates numerous biological processes and diverse cancers.
Objective: To explore the frequency distribution of METTL3 rs1061026, rs1139130, and rs1263801 polymorphisms, and their potential impacts on clinical outcomes and chemotherapy-induced toxicities in a cohort of Chinese pediatric patients diagnosed with primary brain tumors (PBTs).
Methods: Genotyping for three investigated SNPs was performed in 107 pediatric patients with PBTs using the Sequenom MassARRAY iPLEX platform.
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