Visualization of Cortex Organization and Dynamics in Microorganisms, using Total Internal Reflection Fluorescence Microscopy
Total Internal Reflection Fluorescence (TIRF) microscopy is a powerful approach to observe structures close to the cell surface at high contrast and temporal resolution. We demonstrate how TIRF can be employed to study protein dynamics at the cortex of cell wall-enclosed bacterial and fungal cells.
We describe how to measure near membrane and global intracellular calcium dynamics in cultured astrocytes using total internal reflection and epifluorescence microscopy.
A TIRF Microscopy Technique for Real-time, Simultaneous Imaging of the TCR and its Associated Signaling Proteins
The compartmentalization of proteins either within the plasma membrane or into intracellular locations is one regulatory mechanism that can greatly influence signaling outcomes; hence, to understand signaling it is important to study the spatial and temporal behavior of the proteins involved. We describe here a TIRF microscopy based system to study signal transduction in T cells, but is broadly applicable.
Live Cell Response to Mechanical Stimulation Studied by Integrated Optical and Atomic Force Microscopy
1Department of Systems Biology and Translational Medicine, College of Medicine, Cardiovascular Research Institute, Texas A&M Health Science Center, 2Department of Biomedical Engineering, Texas A&M University
This paper aims to instruct the reader in the operation of an integrated atomic force-optical imaging microscope for mechanical stimulation of live cells in culture. A step-by-step protocol is presented. A representative data set that shows live cell response to mechanical stimulation is presented.
1Department of Pathology, New York University Langone School of Medicine, 2Program in Molecular Pathogenesis, Marty and Helen Kimmel Center for Biology and Medicine and Skirball Institute for Biomolecular Medicine, 3Laboratory of Molecular Immunogenetics, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, 4Veteran Affairs New York Harbor Healthcare System
This article describes a method to visualize formation of an HIV-1 envelope-induced virological synapse on glass supported planar bilayers by total internal reflection fluorescence (TIRF) microscopy. The method can also be combined with immunofluorescence staining to detect activation and redistribution of signaling molecules that occur during HIV-1 envelope-induced virological synapse formation.
By tagging the extracellular domains of membrane receptors with superecliptic pHluorin, and by imaging these fusion receptors in cultured mouse neurons, we can directly visualize individual vesicular insertion events of the receptors to the plasma membrane. This technique will be instrumental in elucidating the molecular mechanisms governing receptor insertion to the plasma membrane.
Nano-fEM: Protein Localization Using Photo-activated Localization Microscopy and Electron Microscopy
We describe a method to localize fluorescently tagged proteins in electron micrographs. Fluorescence is first localized using photo-activated localization microscopy on ultrathin sections. These images are then aligned to electron micrographs of the same section.
Here we demonstrate the protocols for performing single-molecule fluorescence microscopy on living bacterial cells to enable functional molecular complexes to be detected, tracked and quantified.
In this video, we demonstrate how to label and visualize single synaptic vesicle exocytosis and trafficking in goldfish retinal bipolar cells using total internal reflectance fluorescence (TIRF) microscopy.
This video shows experiments with subsequent analysis of protein-protein interactions by the use of micro-patterned surfaces. The approach offers the possibility to detect protein interactions in living cells and combines high throughput capabilities with the possibility to extract quantitative information.
A method to measure the persistence length or flexural rigidity of biopolymers is described. The method uses a kinesin-driven microtubule gliding assay to experimentally determine the persistence length of individual microtubules and is adaptable to actin-based gliding assays.
Imaging G-protein Coupled Receptor (GPCR)-mediated Signaling Events that Control Chemotaxis of Dictyostelium Discoideum
Here, we describe detailed live cell imaging methods for investigating chemotaxis. We present fluorescence microscopic methods to monitor spatiotemporal dynamics of signaling events in migrating cells. Measurement of signaling events permits us to further understand how a GPCR-signaling network achieves gradient sensing of chemoattractants and controls directional migration of eukaryotic cells.
Supported planar bilayers are powerful tools that can be used to model the molecular interactions in an immunological synapse. Here, we show methods for anchoring cell adhesion proteins known to modulate synapse formation to the upper leaflet of the lipid bilyer and visualize synapse formation using TIRF microscopy.
This protocol demonstrates a simple single-molecule fluorescence microscopy technique for visualizing DNA replication by individual replisomes in real time.
In this article we describe how we obtain FRET traces from individual DNA molecules immobilized to a surface using an automated scanning confocal microscope.
1Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, 2Department of Mechanical and Aerospace Engineering, The Ohio State University, 3Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, 4Dept. of Chemical and Biomolecular Engineering, Vanderbilt University
A method is described to individually select, manipulate, and image live pathogens using an optical trap coupled to a spinning disk microscope. The optical trap provides spatial and temporal control of organisms and places them adjacent to host cells. Fluorescence microscopy captures dynamic intercellular interactions with minimal perturbation to cells.
We describe the preparation of colloidal quantum dots with minimized hydrodynamic size for single-molecule fluorescence imaging. Compared to conventional quantum dots, these nanoparticles are similar in size to globular proteins and are optimized for single-molecule brightness, stability against photodegradation, and resistance to nonspecific binding to proteins and cells.
Nanotopology of Cell Adhesion upon Variable-Angle Total Internal Reflection Fluorescence Microscopy (VA-TIRFM)
Topology of cell adhesion on a substrate is measured with nanometre precision by variable-angle total internal reflection fluorescence microscopy (VA-TIRFM).
We present an in vitro, two-color fluorescence assay to visualize the fusion of single virus particles with a fluid target bilayer. By labeling viral particles with fluorophores that differentially stain the viral membrane and its interior, we are able to monitor the kinetics of hemifusion and pore formation.
1Departments of Neurology, Columbia University, 2Departments of Psychiatry and Pharmacology, Columbia University, 3Department of Chemistry, Columbia University, 4eMolecules, Inc., 5Departments of Neurology and Physiology, University of California School of Medicine, San Francisco, 6Division of Molecular Therapeutics, New York Psychiatric Institute
A new means to measure neurotransmission optically using fluorescent dopamine analogs.
Determination of Lipid Raft Partitioning of Fluorescently-tagged Probes in Living Cells by Fluorescence Correlation Spectroscopy (FCS)
1Centre de Recherche de l’Institut du Cerveau et de la Moelle Épinière, Hôpital de la Pitié-Salpêtrière, 2Institut des Sciences Moléculaires d'Orsay, Université Paris-Sud, 3Centre de Photonique Biomédicale du Centre Laser, Université Paris-Sud
A technique to probe the lipid raft partitioning of fluorescent proteins at the plasma membrane of living cells is described. It takes advantage of the disparity in diffusion times of proteins located inside or outside of lipid rafts. Acquisition can be performed dynamically in control conditions or after drug addition.
The mesothelial clearance assay described here takes advantage of fluorescently labeled cells and time-lapse video microscopy to visualize and quantitatively measure the interactions of ovarian cancer multicellular spheroids and mesothelial cell monolayers. This assay models the early steps of ovarian cancer metastasis.
1Institut National de la Santé et de la Recherche Médicale, UMR 631, Parc scientifique de Luminy, 2Centre National de la Recherche Scientifique, UMR 6102, Parc scientifique de Luminy, 3Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 4École Centrale Marseille, Technopôle de Château-Gombert, 5Institut Fresnel, Aix-Marseille University, 6Centre National de la Recherche Scientifique, UMR 6133, Aix-Marseille University
Multiple-Target Tracing is a homemade algorithm developed for tracking individually labeled molecules within the plasma membrane of living cells. Efficiently detecting, estimating and tracing molecules over time at high-density provide a user-friendly, comprehensive tool to investigate nanoscale membrane dynamics.