JoVE General
Flow Cytometry Purification of Mouse Meiotic Cells
1Genome Plasticity Laboratory, Department of Cancer Biology, The Scripps Research Institute, 2Flow Cytometry Core, The Scripps Research Institute
An efficient method to obtain highly purified viable meiotic fractions from mouse testis is described, which combines a refined cell dissociation protocol with fluorescent activated cell sorting (FACS). This method takes advantage of differences in the DNA content and nuclear density of discrete meiotic fractions.
JoVE General
Assembly, Loading, and Alignment of an Analytical Ultracentrifuge Sample Cell
The analytical ultracentrifuge (AUC) sample cell holds sample and reference buffer and during experiments and is exposed to high vacuum and rotor speeds up to 60,000 rpm. This video will demonstrate the rigorous attention to detail necessary for assembly, loading and alignment of this very important component of an AUC experiment.
JoVE General
Isolation and Purification of Kinesin from Drosophila Embryos
This is a protocol to isolate active full length Kinesin from Drosophila embryos for single-molecule biophysical studies. We show how to collect embryos, make the embryo lysate, and then polymerize microtubules (MTs). Kinesin is purified by immobilizing it on the MTs, spinning down the Kinesin-MT complexes, and then releasing the kinesin from the MTs via ATP addition.
JoVE Bioengineering
Micro-particle Image Velocimetry for Velocity Profile Measurements of Micro Blood Flows
1Department of Chemical and Biological Engineering, University of Ottawa, 2Department of Mechanical Engineering, University of Ottawa
Micro-particle image velocimetry (μPIV) is used to visualize paired images of micro particles seeded in blood flows which are cross-correlated to give an accurate velocity profile. Shear rate, maximum velocity, velocity profile shape, and flow rate, each of which has clinical applications, can be derived from these measurements.
JoVE Clinical and Translational Medicine
Isolation of Soluble and Insoluble PrP Oligomers in the Normal Human Brain
1Department of Pathology, National Prion Disease Pathology Surveillance Center, Case Western Reserve University School of Medicine, 2Department of Neurology, National Prion Disease Pathology Surveillance Center, Case Western Reserve University School of Medicine
A new species of cellular prion protein (PrPC) has recently been identified in uninfected human brains using the methods described here. These methods can be used to isolate various PrP species, while some of them are also useful in isolating other misfolded protein aggregates from human brains.
JoVE General
Using SecM Arrest Sequence as a Tool to Isolate Ribosome Bound Polypeptides
We describe here a technique that is now routinely used to isolate stably bound ribosome nascent chain complexes (RNCs). This technique takes advantage of the discovery that a 17 amino acid long SecM "arrest sequence" can halt translation elongation in a prokaryotic (E. coli) system, when inserted into (or fused to the C-terminus) of virtually any protein.
JoVE General
Purification and Visualization of Influenza A Viral Ribonucleoprotein Complexes
Department of Zoology, University of British Columbia - UBC
The genome of the influenza A virus consists of eight separate complexes of RNA and proteins, termed viral ribonucleoprotein complexes (vRNPs). This paper describes the glycerol gradient purification and transmission electron microscopy visualization of influenza A vRNPs.
JoVE General
Actin Co-Sedimentation Assay; for the Analysis of Protein Binding to F-Actin
Department of Cell and Tissue Biology, University of California, San Francisco - UCSF
Proteins bind to filamentous actin (F-actin) through distinct actin binding modules. In this video we demonstrate the procedure of actin co-sedimentation, which is an in vitro assay routinely used to analyze proteins or specific domains that bind F-actin.
JoVE General
Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes
1Experimental and Clinical Research Center (ECRC), Charité Medical Faculty and Max-Delbrück Center for Molecular Medicine (MDC), 2Medical Department, Division of Cardiology, Campus Virchow-Klinikum, Charité - Universitätsmedizin Berlin, 3Medical Department, Division of Cardiology and Angiology, Campus Mitte, Charité - Universitätsmedizin Berlin
Kv channel dysfunction is associated with cardiac arrhythmias. In order to study the molecular mechanisms that lead to such arrhythmias we utilize a systematic protocol for isolation of atrial and ventricular cardiomyocytes from Kv channel ancillary subunit knockout mice. Isolated cardiomyocytes can then immediately be used for cellular electrophysiological studies, biochemical or immunofluorescence (IF) assays.
JoVE Applied Physics
Echo Particle Image Velocimetry
Mechanical Engineering Department, University of New Hampshire
An echo particle image velocimetry (EPIV) system capable of acquiring two-dimensional fields of velocity in optically opaque fluids or through optically opaque geometries is described, and validation measurements in pipe flow are reported.
JoVE Neuroscience
Three Dimensional Vestibular Ocular Reflex Testing Using a Six Degrees of Freedom Motion Platform
1Department of Neuroscience, Erasmus MC, 2TNO Human Factors
A method is described to measure three-dimensional vestibulo ocular reflexes (3D VOR) in humans using a six degrees of freedom (6DF) motion simulator. The gain and misalignment of the 3D angular VOR provide a direct measure of the quality of vestibular function. Representative data on healthy subjects are provided
JoVE Bioengineering
Three-dimensional Cell Culture Model for Measuring the Effects of Interstitial Fluid Flow on Tumor Cell Invasion
School of Biomedical Engineering, Science and Health Systems, Drexel University
Interstitial fluid flow is elevated in solid tumors and can modulate tumor cell invasion. Here we describe a technique to apply interstitial fluid flow to cells embedded in a matrix and then measure its effects on cell invasion. This technique can be easily adapted to study other systems.
JoVE Applied Physics
Determining 3D Flow Fields via Multi-camera Light Field Imaging
1Department of Mechanical Engineering, Brigham Young University, 2Naval Undersea Warfare Center, Newport, RI
A technique for performing quantitative three-dimensional (3D) imaging for a range of fluid flows is presented. Using concepts from the area of Light Field Imaging, we reconstruct 3D volumes from arrays of images. Our 3D results span a broad range including velocity fields and multi-phase bubble size distributions.
JoVE Neuroscience
VisioTracker, an Innovative Automated Approach to Oculomotor Analysis
1Institute of Molecular Life Sciences, University of Zurich, 2TSE Systems GmbH
The VisioTracker is an automated system for the quantitative analysis of visual performance of larval and small adult fish based on the recording of eye movements. It features full control over visual stimulus properties and real-time analysis, enabling high-throughput research in fields such as visual system development and function, pharmacology, neural circuit studies and sensorimotor integration.
JoVE Neuroscience
C. elegans Tracking and Behavioral Measurement
1Donnelly Centre, University of Toronto, 2Department of Physics and Astronomy, Vrije Universiteit, 3Okinawa Institute of Science and Technology, 4Department of Physics, University of Toronto
We have developed a video-rate tracking microscope system that can record and quantify C. elegans behavior at high resolution and high speeds. We have also developed computational methods to reduce the dimensionality of the worm images to a fundamental set of measurements that completely describe the shape of the worm.
JoVE Clinical and Translational Medicine
Tilt Testing with Combined Lower Body Negative Pressure: a "Gold Standard" for Measuring Orthostatic Tolerance
Department of Biomedical Physiology and Kinesiology, Simon Fraser University
We describe a "gold standard" for evaluating orthostatic tolerance (OT) using tilt testing with combined lower body negative pressure (LBNP). This can be combined with non-invasive evaluations of cardiovascular reflex control. Normal and abnormal responses are defined.
JoVE General
Zebrafish Brain Ventricle Injection
1Whitehead Institute for Biochemical Research, 2MIT - Massachusetts Institute of Technology
After neural tube formation, the neuroepithelium constricts and folds while the tube fills with embryonic cerebrospinal fluid (eCSF) to form the embryonic brain ventricles. We developed this ventricle injection technique to better visualize the fluid filled space in contrast to the neuroepithelial shape in a live embryo.
JoVE General
In vivo Micro-circulation Measurement in Skeletal Muscle by Intra-vital Microscopy
1Department of Anesthesiology and Critical Care, Shriners Hospital for Children, Massachusetts General Hospital, and Harvard Medical School, 2Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo
A new versatile method for observation of microcirculation is presented. It is considered suitable for long-term observation, and for combination with pharmacophysiological or molecular biological interventions.
JoVE Clinical and Translational Medicine
High-frequency High-resolution Echocardiography: First Evidence on Non-invasive Repeated Measure of Myocardial Strain, Contractility, and Mitral Regurgitation in the Ischemia-reperfused Murine Heart
1Department of Surgery, The Ohio State University, 2Heart and Lung Research Institute, The Ohio State University, 3Department of Cardiovascular Medicine, The Ohio State University
High frequency Doppler ultrasound is a novel technology for assessing regional myocardial function. This work presents first evidence demonstrating applicability of this versatile imaging platform for the repeated measure of myocardial strain, dp/dt, and mitral regurgitation in the ischemia-reperfused (IR) murine heart.
JoVE Clinical and Translational Medicine
Transthoracic Echocardiography in Mice
1Department of Molecular Physiology and Biophysics, Baylor College of Medicine (BCM), 2The Margaret M. and Albert B. Alkek Department of Medicine, Baylor College of Medicine (BCM)
Transthoracic echocardiography offers a noninvasive method for the evaluation of cardiac function in mice. A combination of ultrasound and Doppler imaging modalities can be used to obtain dimensional measurements of the heart and intracardiac blood flow, which together provide an assessment of cardiac systolic and diastolic performance.
JoVE General
Flow Cytometry-based Purification of S. cerevisiae Zygotes
1Department of Pathology, Case Western Reserve University School of Medicine, 2Cell Biology Program, Case Western Reserve University School of Medicine, 3Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine
To purify zygotes of S. cerevisiae, haploid cells of opposite mating type were engineered to express red or green fluorescent proteins, co-incubated to allow zygote formation, and fractionated using a flow cytometry-based protocol. The highly-enriched fraction enables subsequent "-omic" studies, recovery of initial progeny, and systematic investigation of zygote morphogenesis.
JoVE Neuroscience
Intravital Microscopy of the Mouse Brain Microcirculation using a Closed Cranial Window
1Bioengineering, University of California, San Diego, 2La Jolla Bioengineering Institute
Intravital microscopy to follow temporal and spatial hemodynamic and inflammatory events in the pial microcirculation.
JoVE General
High Speed Droplet-based Delivery System for Passive Pumping in Microfluidic Devices
1Materials Science Program, University of Wisconsin-Madison, 2Department of Biomedical Engineering, University of Wisconsin-Madison
A novel microfluidic system has been developed using the phenomenon of passive pumping and a user controlled fluid delivery system. This microfluidic system has the potential to be used in a wide variety of biological applications given its low cost, ease of use, volumetric precision, high speed, repeatability and automation.
JoVE Clinical and Translational Medicine
Doppler Optical Coherence Tomography of Retinal Circulation
1Department of Ophthalmology, Oregon Health and Science University, 2Department of Ophthalmology, University of Southern California
Total retinal blood flow is measured by Doppler optical coherence tomography and semi-automated grading software.
JoVE General
In vivo Imaging of Deep Cortical Layers using a Microprism
Department of Biomedical Engineering, Yale University
Right-angle microprisms inserted into the mouse neocortex allows for deep imaging of multiple cortical layers with a viewpoint typically found in slice. One-millimeter microprisms offer a wide field-of-view (~900 μm) and spatial resolutions sufficient to resolve dendritic spines. We demonstrate layer V neuronal imaging and neocortical vascular imaging using microprisms.
JoVE Neuroscience
Video-oculography in Mice
1Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands, 2Department of Neuroscience, Royal Dutch Academy of Arts & Sciences (KNAW)
Video-oculography is a very quantitative method to investigate ocular motor performance as well as motor learning. Here, we describe how to measure video-oculography in mice. Applying this technique on normal, pharmacologically-treated or genetically modified mice is a powerful research tool to explore the underlying physiology of motor behaviors.
JoVE Neuroscience
Assessment of Cerebral Lateralization in Children using Functional Transcranial Doppler Ultrasound (fTCD)
Department of Experimental Psychology, University of Oxford
Functional transcranial Doppler sonography (fTCD) is a simple and non-invasive ultrasound technique which can be used to assess the lateralization of cognitive functions, especially language, and is suitable for use with children.
JoVE Neuroscience
Automated Interactive Video Playback for Studies of Animal Communication
1Department of Visualization, Texas A&M University (TAMU), 2Department of Biology, Texas A&M University (TAMU)
Video playback is a widely used technique in animal behavior. We created and evaluated a program that applies rules-based, interactive playback of 3-D computer animations in response to real-time, automated data on subject behavior.
JoVE Bioengineering
Separating Beads and Cells in Multi-channel Microfluidic Devices Using Dielectrophoresis and Laminar Flow
1Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 2Micro and Nanotechnology Lab, University of Illinois at Urbana-Champaign, 3Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 4Bioengineering, University of Illinois at Urbana-Champaign
Dielectrophoresis (DEP) is an effective method to manipulate cells. Printed circuit boards (PCB) can provide inexpensive, reusable and effective electrodes for contact-free cell manipulation within microfluidic devices. By combining PDMS-based microfluidic channels with coverslips on PCBs, we demonstrate bead and cell manipulation and separation within multichannel microfluidic devices.
JoVE Bioengineering
Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus (SCUVA)
1Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, 2Environmental Science and Marine Biology, Roger Williams University, 3Marine Biology Laboratory, Whitman Center, 4Department of Biology, Providence College, 5Departments of Aeronautics and Bioengineering, California Institute of Technology
This protocol provides instructions on how to use a self-contained underwater velocimetry apparatus (SCUVA), which is designed for quantification of in situ animal-generated flows. In addition, this protocol addresses challenges posed by field conditions, and includes operator motion, predicting position of animals, and orientation of SCUVA.
JoVE Bioengineering
Microfluidic-based Electrotaxis for On-demand Quantitative Analysis of Caenorhabditis elegans' Locomotion
1Department of Biology, McMaster University, 2Department of Mechanical Engineering, McMaster University
A semi-automated micro-electro-fluidic method to induce on-demand locomotion in Caenorhabditis elegans is described. This method is based on the neurophysiologic phenomenon of worms responding to mild electric fields (“electrotaxis”) inside microfluidic channels. Microfluidic electrotaxis serves as a rapid, sensitive, low-cost, and scalable technique to screen for factors affecting neuronal health.
JoVE General
T-wave Ion Mobility-mass Spectrometry: Basic Experimental Procedures for Protein Complex Analysis
Department of Biological Chemistry, Weizmann Institute of Science
Ion mobility-mass spectrometry is an emerging gas-phase technology that separates ions, based on their collision cross-section and mass. The method provides three-dimensional information on the overall topology and shape of protein complexes. Here, we outline a basic procedure for instrument setting and optimization, calibration of drift times, and data interpretation.
JoVE Immunology and Infection
Tracking Neutrophil Intraluminal Crawling, Transendothelial Migration and Chemotaxis in Tissue by Intravital Video Microscopy
Department of Pharmacology, University of Saskatchewan
We describe a protocol of brightfield intravital microscopy for measuring dynamic neutrophil-endothelial cell interactions during neutrophil recruitment in response to the source of a neutrophil chemoattractant in vivo. Neutrophil intraluminal crawling, transendothelial migration and chemotaxis in mouse cremaster muscle tissue are visualized with time-lapsed video photography and tracked with ImageJ.
JoVE Clinical and Translational Medicine
Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain
1Department of Surgery, University of Texas Medical Branch, 2Department of Neuroscience and Cell Biology, University of Texas Medical Branch
A method for large-scale purification of the APP intracellular domain (AICD) is described. We also describe methodology to induce in vitro AICD aggregation and visualization by atomic force microscopy. The methods described are useful for biochemical/structural characterization of the AICD and the effects of molecular chaperones on its aggregation.
JoVE Clinical and Translational Medicine
Isolation of Cardiomyocyte Nuclei from Post-mortem Tissue
1Strategic Research Center for Stem Cell Biology and Cell Therapy, University of Lund, 2Department of Cardiology Lund University Hospital, University of Lund
Cardiac nuclei are isolated via density sedimentation and immunolabeled with antibodies against pericentriolar material 1 (PCM-1) to identify and sort cardiomyocyte nuclei by flow cytometry.
JoVE General
Transverse Aortic Constriction in Mice
1Department of Molecular Physiology and Biophysics, Baylor College of Medicine (BCM), 2The Margaret M. and Albert B. Alkek Department of Medicine, Baylor College of Medicine (BCM)
Transverse aortic constriction (TAC) in the mouse is a commonly used experimental model to study mechanisms underlying cardiac hypertrophy and heart failure development. Here, we describe procedures to constrict the aorta to create a reproducible degree of cardiac hypertrophy in mice.
JoVE Bioengineering
Studying Cell Rolling Trajectories on Asymmetric Receptor Patterns
1Department of Materials Science and Engineering, MIT - Massachusetts Institute of Technology, 2Department of Mechanical Engineering, MIT - Massachusetts Institute of Technology, 3HST Center for Biomedical Engineering and Harvard Stem Cell Institute, Brigham and Women's Hospital and Harvard Medical School
We describe a protocol to observe and analyze cell rolling trajectories on asymmetric receptor-patterned substrates. The resulting data are useful for engineering of receptor-patterned substrates for label-free cell separation and analysis.
JoVE Clinical and Translational Medicine
Magnetic Resonance Derived Myocardial Strain Assessment Using Feature Tracking
1The Heart Institute, Cincinnati Children Hospital Medical Center (CCHMC), 2TomTec, Imaging Systems GmbH, 3AMID, Advanced Medical Imaging Development SRL, 4The Heart and Vascular Center, The Christ Hospital
An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF.
JoVE Bioengineering
Increasing cDNA Yields from Single-cell Quantities of mRNA in Standard Laboratory Reverse Transcriptase Reactions using Acoustic Microstreaming
1Florey Neuroscience Institutes and Centre for Neuroscience, University of Melbourne, 2Fluid Dynamics Group, CSIRO Materials Science and Engineering, 3Swinburne University of Technology, Faculty of Engineering and Industrial Sciences
We describe a novel method for increasing cDNA yield from single-cell quantities of mRNA in otherwise standard laboratory reverse transcription reactions. The novelty resides in the use of a micromixer, which utilizes the phenomenon of acoustic microstreaming, to mix fluids at microliter scales more effectively than shaking, vortexing or trituration.
JoVE General
Study of the Actin Cytoskeleton in Live Endothelial Cells Expressing GFP-Actin
Department of Physiology, Louisiana State University Health Sciences Center
Microscopic imaging of live endothelial cells expressing GFP-actin allows characterization of dynamic changes in cytoskeletal structures. Unlike techniques that use fixed specimens, this method provides a detailed assessment of temporal changes in the actin cytoskeleton in the same cells before, during, and after various physical, pharmacological, or inflammatory stimuli.
JoVE Immunology and Infection
A New Screening Method for the Directed Evolution of Thermostable Bacteriolytic Enzymes
Institute for Bioscience and Biotechnology Research, University of Maryland
A novel directed evolution method specific to the field of thermostability engineering was developed and consequently validated for bacteriolytic enzymes. After only one round of random mutagenesis, an evolved bacteriolytic enzyme, PlyC 29C3, displayed greater than twice the residual activity when compared to the wild-type protein after elevated temperature incubation.
JoVE General
Analysis of Gene Function and Visualization of Cilia-Generated Fluid Flow in Kupffer's Vesicle
1Department of Cell and Developmental Biology, State University of New York, Upstate Medical University, 2Department of Neurobiology and Anatomy, Eccles Institute of Human Genetics, University of Utah
Cilia-generated fluid flow in Kupffer’s Vesicle (KV) controls left-right patterning of the zebrafish embryo. Here, we describe a technique to modulate gene function specifically in KV cells. In addition, we show how to deliver fluorescent beads into KV to visualize fluid flow.
JoVE General
Tissue Targeted Embryonic Chimeras: Zebrafish Gastrula Cell Transplantation
Department of Biological Sciences, Smith College
Zebrafish cell transplantation enables the combination of genetics and embryology to generate tissue specific chimeras. This video demonstrates gastrula staged cell transplantations that have allowed our lab to investigate the roles of astroglial populations and specific guidance cues during commissure formation in the forebrain.
JoVE Neuroscience
An Experimental Platform to Study the Closed-loop Performance of Brain-machine Interfaces
Department of Bioengineering, Imperial College London
We use a closed-loop fly-machine interface to investigate general principles in neuronal control.
JoVE Immunology and Infection
Human T Lymphocyte Isolation, Culture and Analysis of Migration In Vitro
Center for Vaccine Biology and Immunology, University of Rochester
T lymphocyte migration occurs during homing to lymphoid organs, exit from the vasculature, and entering into peripheral tissues. Here, we describe a protocol that can be used to analyze T lymphocyte migration in vitro.
JoVE Clinical and Translational Medicine
Murine Fetal Echocardiography
Fetal and perinatal death is a common feature when studying genetic alterations affecting cardiac development. High-frequency ultrasound imaging has improved 2-D resolution and can provide excellent information on early cardiac development and is an ideal method to detect the impact on cardiac structure and function prior to death.
JoVE Immunology and Infection
Multicolor Flow Cytometry Analyses of Cellular Immune Response in Rhesus Macaques
1Department of Immunology, MD Anderson Cancer Center - University of Texas, 2Department of Medicine, University of Miami
We demonstrate the utility of multicolor flow cytometry for detailed phenotypic and functional characterization of total as well as memory subsets of CD4+ and CD8+ T cells in rhesus macaques, the ideal model for HIV/AIDS vaccine studies.
JoVE General
Procedures for Rat in situ Skeletal Muscle Contractile Properties
Faculty of Kinesiology, University of Calgary
This video demonstrates the surgical preparation and procedures needed to study the contractile responses of the rat medial gastrocnemius muscle preparation in situ. This preparation allows measurement of skeletal muscle contractile properties under physiological conditions. The animal is anesthetized and the muscle is separated from surrounding tissue at its distal end. The Achilles tendon is attached to a force transducer, allowing measurement of the muscle’s contractile response at 37 degrees C with an intact circulation.
JoVE General
Chromatographic Purification of Highly Active Yeast Ribosomes
1Department of Cell Biology and Molecular Genetics, University of Maryland, 2Department of Biotechnology and Microbiology, Vilnius University
Contamination of preparations of eukaryotic ribosomes purified by traditional methods by co-purifying nucleases and proteases negatively impacts on downstream biochemical and structural analyses. A rapid and simple chromatographic purification method is used to solve this problem using yeast ribosomes as a model system.
JoVE Clinical and Translational Medicine
Implantation of a Carotid Cuff for Triggering Shear-stress Induced Atherosclerosis in Mice
1European Institute for Molecular Imaging, Westfälische Wilhelms-University Münster, 2British Heart Foundation Cardiovascular Sciences Unit, Imperial College London, 3Department of Bioengineering, Imperial College London, 4Biomedical Engineering, Eindhoven University of Technology
The constricting cuff presented in this article is designed to induce atherosclerosis in the murine common carotid artery. Due to the conical shape of its inner lumen the implanted cuff generates well-defined regions of low, high and oscillatory shear stress triggering the development of atherosclerotic lesions of different inflammatory phenotypes.
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