JoVE General
Herbivore-induced Blueberry Volatiles and Intra-plant Signaling
Department of Entomology, Rutgers University
A push-pull method for collecting plant volatiles is described. The method allows for a comparison of volatiles induced by herbivore feeding, exogenous methyl jasmonate, and mechanical damage. This technique is also used to investigate the volatile response of undamaged branches to exposure to volatiles from herbivore-damaged branches within blueberry plants.
JoVE Bioengineering
Characterizing Bacterial Volatiles using Secondary Electrospray Ionization Mass Spectrometry (SESI-MS)
School of Engineering, University of Vermont
Secondary electrospray ionization mass spectrometry (SESI-MS) enables the detection of volatile organic compounds (VOCs) without the need for any sample pretreatment. This protocol provides instructions for the rapid (within minutes) characterization of bacterial VOCs using SESI-MS.
JoVE General
Electroantennographic Bioassay as a Screening Tool for Host Plant Volatiles
Plant Mycotoxin Research, U.S. Department of Agriculture, Agricultural Research Service
A method to rapidly screen host plant volatiles by measurement of the electrophysiological response of adult navel orangeworm (Amyelois transitella) antennae to single components and blends via electroantennographic analysis is demonstrated.
JoVE Neuroscience
Identification of Olfactory Volatiles using Gas Chromatography-Multi-unit Recordings (GCMR) in the Insect Antennal Lobe
Department of Biology, University of Washington
Olfactory cues mediate many different behaviors in insects, and are often complex mixtures comprised of tens to hundreds of volatile compounds. Using gas chromatography with multi-channel recording in the insect antennal lobe, we describe a method for the identification of bioactive compounds.
JoVE Neuroscience
Vertical T-maze Choice Assay for Arthropod Response to Odorants
Entomology and Nematology Department, University of Florida
A vertical, T-maze olfactometer is described for assaying the behavioral response of arthropods. The olfactometer allows the experimenter to measure choices performed by test subjects when subjected to two potential odor fields. Both attraction to and repulsion from odorants can be measured with this device.
JoVE General
Fruit Volatile Analysis Using an Electronic Nose
1Department of Plant Sciences, University of California, Davis, 2Department of Chemical Engineering and Material Science, University of California, Davis, 3Department of Viticulture and Enology, University of California, Davis
A rapid method for volatile compound analysis in fruit is described. The volatile compounds present in the headspace of a homogenate of the sample are rapidly separated and detected with ultra-fast gas chromatography (GC) coupled with a surface acoustic wave (SAW) sensor. A procedure for data handling and analysis is also discussed.
JoVE Editorial
May 2012: This Month in JoVE
Here are some highlights from the May 2012 Issue of Journal of Visualized Experiments (JoVE).
JoVE Neuroscience
Imaging Pheromone Sensing in a Mouse Vomeronasal Acute Tissue Slice Preparation
1Department of Pharmacology and Toxicology, University of Lausanne, 2Department of Genetics and Evolution, University of Geneva
In mice, the ability to detect pheromones is principally mediated by the vomeronasal organ (VNO). Here, an acute tissue slice preparation of VNO for performing calcium imaging is described. This physiological approach allows observations of subpopulations and/or individual neurons in a living tissue and is convenient for receptor-ligand identification.
JoVE General
Isolation of Native Soil Microorganisms with Potential for Breaking Down Biodegradable Plastic Mulch Films Used in Agriculture
1Biology Department, Western Washington University, 2Washington State University Northwestern Research and Extension Center, 3Department of Plant and Soil Science, Texas Tech University
Plastic films labeled "biodegradable" are commercially available for agricultural use as mulches. Tillage represents an attractive disposal method, but degradation under field conditions is poorly understood. The purpose of this study was to develop methods for isolating native soil fungi and bacteria that colonize plastic mulch films after field burial.
JoVE Chemistry
Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development
ISOF - Bio Free Radicals, Consiglio Nazionale delle Ricerche
Radical-based biomimetic chemistry has been applied to building-up libraries necessary for biomarker development.
JoVE Bioengineering
Continuously-stirred Anaerobic Digester to Convert Organic Wastes into Biogas: System Setup and Basic Operation
Department of Biological and Environmental Engineering, Cornell University
Laboratory-scale anaerobic digesters allow scientists to research new ways of optimizing existing applications of anaerobic biotechnology and to evaluate the methane producing potential of various organic wastes. This article introduces a generalized model for the construction, inoculation, operation, and monitoring of a laboratory-scale continuously stirred anaerobic digester.
JoVE Editorial
March 2012: This Month in JoVE
Here are some highlights from the March 2012 Issue of Journal of Visualized Experiments (JoVE).
JoVE Bioengineering
Electrospinning Fundamentals: Optimizing Solution and Apparatus Parameters
1Department of Biomedical Engineering, University of Michigan, 2State Key Laboratory of Bioelectronics, Southeast University, 3Department of Neurology, University of Michigan, 4Geriatrics Research, Education and Clinical Center, Veterans Affairs Ann Arbor Healthcare Center
Electrospinning techniques can create a variety of nanofibrous scaffolds for tissue engineering or other applications. We describe here a procedure to optimize the parameters of the electrospinning solution and apparatus to obtain fibers with the desired morphology and alignment. Common problems and troubleshooting techniques are also presented.
JoVE General
Monitoring Plant Hormones During Stress Responses
Department of Biology, University of Texas
A simple method is provided that allows for the rapid extraction and analysis of multiple plant hormones from small tissue samples. The procedure uses vapor phase extraction as the solemn purification step. Samples are analyzed by GC/MS with chemical ionization that produces mainly (M+1)+ ions.
JoVE General
Drawing Blood from Rats through the Saphenous Vein and by Cardiac Puncture
Department of Physiology and Biophysics, University of California, Irvine (UCI)
Blood draws are necessary in a large number of studies, for example to study the pharmacokinetics profile of a compound. Here, we demonstrate how to draw blood from rats using two techniques: blood draw from the saphenous vein or by cardiac puncture.
JoVE Clinical and Translational Medicine
A Murine Closed-chest Model of Myocardial Ischemia and Reperfusion
1Department of Anesthesiology and Intensive Care Medicine, University of Bonn, Germany, 2Institute of Physiology, University of Bonn, Germany
Surgical trauma induces an inflammatory response. Cytokines and endogenous ligands are known to modulate myocardial infarct size following ischemia and reperfusion. We present a modified closed-chest model of murine ischemia and reperfusion using hanging weights to minimize effects of thoracotomy.
JoVE Bioengineering
Polymer Microarrays for High Throughput Discovery of Biomaterials
1Laboratory of Biophysics and Surface Analysis, University of Nottingham, 2School of Molecular Medical Sciences, University of Nottingham, 3David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology
A description of the formation of a polymer microarray using an on-chip photopolymerization technique. The high throughput surface characterization using atomic force microscopy, water contact angle measurements, X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry and a cell attachment assay is also described.
JoVE Immunology and Infection
Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction
Department of Microbiology, Immunology, & Cancer Biology, University of Virginia Health System
We describe a modified hot aqueous-phenol extraction method for purifying lipopolysaccharide (LPS) from Gram-negative bacteria. Once extracted, the LPS can be subsequently analyzed by SDS-PAGE and visualized by direct staining or Western immunoblot.
JoVE General
Analyzing Large Protein Complexes by Structural Mass Spectrometry
Department of Biological Chemistry, Weizmann Institute of Science
Mass spectrometry has proven to be a valuable tool for analyzing large protein complexes. This method enables insights into the composition, stoichiometry and overall architecture of multi-subunit assemblies. Here, we describe, step-by-step, how to perform a structural mass spectrometry analysis, and characterize macromolecular structures.
JoVE General
C. elegans Chemotaxis Assay
1Life Sciences, Queen's University, 2Department of Chemical Engineering, Queen's University, 3Department of Biology, Queen's University
A method of quantitatively evaluating the chemotactic response of Caenorhabditis elegans is described. A chemotactic index (CI) was employed as a way to precisely evaluate the response of worms to certain targets, and serve as a platform of comparison between strains and compounds of interest.
JoVE Application Notes
Introduction to eVol - Learn How to Simplify Your Liquid Handling Workflow - ADVERTISEMENT
View this video to learn about the benefits of using your R&D 100 award winning eVol®. eVol® the world's first digital analytical syringe improves the pace of laboratory processes while delivering improved accuracy and reproducibility, with standardized results independent of operator skill.
JoVE General
Photo-Induced Cross-Linking of Unmodified Proteins (PICUP) Applied to Amyloidogenic Peptides
1Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, 2Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, 3Department of Neurology, University of California, Los Angeles
Photo-induced cross-linking of unmodified proteins (PICUP) allows characterization of oligomer size distribution in metastable protein mixtures. We demonstrate application of PICUP to three representative amyloidogenic peptides the 40- and 42-residue forms of amyloid β-protein, and calcitonin, and a control peptide growth-hormone releasing factor.
JoVE Bioengineering
Air Filter Devices Including Nonwoven Meshes of Electrospun Recombinant Spider Silk Proteins
Biomaterials Research Group, University of Bayreuth
Spider silk fibers display extraordinary mechanical properties. Engineered Araneus diadematus Fibroin 4 (eADF4) can be processed into nonwoven meshes using electrospinning. Here, the eADF4 nonwoven meshes are used to improve the performance of air filtering devices.
JoVE Clinical and Translational Medicine
Implantation of Radiotelemetry Transmitters Yielding Data on ECG, Heart Rate, Core Body Temperature and Activity in Free-moving Laboratory Mice
1Division of Surgical Research, University Hospital Zurich, 2Institute of Laboratory Animal Science, University of Zurich
A surgical technique for implantation of commercially available telemetry transmitters used for continuous measurement of biopotential (one-lead ECG), heart rate, core body temperature and locomotor activity in freely moving mice is shown. Recommendations and protocols for post-operative care and pain relief, improving recovery, well being and survival rate are also presented.
JoVE General
Extracting DNA from the Gut Microbes of the Termite (Zootermopsis Angusticollis) and Visualizing Gut Microbes
Department of Environmental Science and Engineering, California Institute of Technology - Caltech
This video illustrates the technique for extracting DNA from the species of microbes resident in the termite hindgut. The preparation of a wet mount slide, which is useful for visualizing the gut microbial community is also illustrated, and a tour through the species-rich gut environment is given.
JoVE Neuroscience
C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays
1Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, 2Lewis-Sigler Institute for Integrative Genomics, Princeton University
Here we describe methods to test C. elegans associative learning and short- and long-term associative memory. These population assays employ the worms abilities to chemotax toward volatile odorants, and form positive associations upon pairing food with the chemoattractant butanone. Increasing the number of conditioning periods induces long-term memory.
JoVE Clinical and Translational Medicine
Use of Animal Model of Sepsis to Evaluate Novel Herbal Therapies
The Feinstein Institute for Medical Research, North Shore – LIJ Health System
Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection, and can be simulated by a surgical technique termed cecal ligation and puncture (CLP). Here we describe a method to use CLP-induced animal model to screen medicinal herbs for therapeutic agents.
JoVE General
Protein Crystallization for X-ray Crystallography
Molecular Biochemistry and Biophysics, Yale University
The 3-D structure of a molecule provides a unique understanding of how the molecule functions. The principal method for structure determination at near-atomic resolution is X-ray crystallography. Here, we demonstrate the current methods for obtaining three-dimensional crystals of any given macromolecule that are suitable for structure determination by X-ray crystallography.
JoVE General
Comprehensive Compositional Analysis of Plant Cell Walls (Lignocellulosic biomass) Part II: Carbohydrates
1Great Lakes Bioenergy Research Center, Michigan State University (MSU), 2Great Lakes Bioenergy Research Center and DOE-Plant Research Lab, Michigan State University (MSU)
Plant biomass is a major carbon-neutral renewable resource that could be used for the production of biofuels. Plant biomass consists mainly of cell walls, a structurally complex composite material termed lignocellulosics. Here we describe a protocol for a comprehensive analysis of the content and composition of wall derived carbohydrates.
JoVE General
Preparation of Adult Drosophila Eyes for Thin Sectioning and Microscopic Analysis
Department of Developmental and Molecular Biology, Albert Einstein College of Medicine
A standard approach to prepare adult Drosophila eyes for semi-thin sectioning and light microscopic analysis is presented here. The protocol can be used for gross morphological analysis of eye defects, or with the indicated adjustments can be used to determine genetic requirements of genes in specific cell types of the eye (e.g. clonal analysis of photoreceptors) or for electron microscopic analysis.
JoVE Clinical and Translational Medicine
Use of a Hanging-weight System for Isolated Renal Artery Occlusion
1Department of Anesthesiology, University of Colorado, 2School of Medicine, University of Colorado, 3Department of Anesthesiology, Korea University College of Medicine
A precise murine model for acute kidney injury (AKI) due to ischemia is an important tool to investigate acute kidney injury and possibly find therapeutic tools to treat renal injury. The hanging weight system offers a tool for immediate and reliable renal artery occlusion and reperfusion without causing renal congestion.
JoVE General
Metabolic Pathway Confirmation and Discovery Through 13C-labeling of Proteinogenic Amino Acids
1Department of Energy, Environmental and Chemical Engineering, Washington University, 2Department of Biology, Washington University, 3Department of Energy, Environmental and Chemical Engineering and Department of Biology, Washington University
13C-isotope labeling is a useful technique for determining the cell central metabolism for various types of microorganisms. After cells have been cultured with a specific labeled substrate, GC-MS measurement can reveal functional metabolic pathways based on unique labeling patterns in proteinogenic amino acids.
JoVE Bioengineering
A Protocol for Detecting and Scavenging Gas-phase Free Radicals in Mainstream Cigarette Smoke
1CDCF-AOX Lab, 2National Biomedical Center for Advanced ESR Technology (ACERT), Department of Chemistry and Chemical Biology, Cornell University
Spin-trapping ESR spectroscopy was used to study the effect of plant antioxidants lycopene, pycnogenol and grape seed extract on scavenging gas-phase free radicals in cigarette smoke.
JoVE General
Arabidopsis thaliana Polar Glycerolipid Profiling by Thin Layer Chromatography (TLC) Coupled with Gas-Liquid Chromatography (GLC)
Department of Biochemistry and Molecular Biology, Michigan State University
Composition of polar lipid extracts and the fatty acid composition of individual glycerolipids are determined in a simple and robust lipid profiling experiment. For this purpose, glycerolipids are isolated by thin layer chromatography and subjected to transmethylation of their acyl groups. Fatty acyl methylesters are quantified by gas-liquid chromatography.
JoVE Neuroscience
Assaying Surface Expression of Chemosensory Receptors in Heterologous Cells
1Department of Molecular Genetics and Molecular Biology , Duke University, 2Department of Chemistry, Duke University
Here we demonstrate a protocol to carry out live cell staining that can be used to detect odorant receptors on the surface of HEK293T cells conveniently. In addition, it may also be used to assay for surface expression of other chemosensory receptors or GPCRs.
JoVE Neuroscience
Electrophysiology of Scorpion Peg Sensilla
Department of Zoology, University of Oklahoma
This article describes an electrophysiological method for isolating chemical stimulation to individual sensilla via extracellular, tip-recordings under mineral oil.
JoVE General
In vivo Imaging of Intact Drosophila Larvae at Sub-cellular Resolution
1Junior Research Group Synaptic Plasticity, Hertie Institute for Clinical Brain Research, University of Tübingen, 2Graduate School of Cellular and Molecular Neuroscience, University of Tübingen
This protocol describes a reliable method for anesthetization and imaging of intact Drosophila melanogaster larvae. We have utilized the volatile anesthetic desflurane to allow for repetitive imaging at sub-cellular resolution and re-identification of structures for up to a few days1.
JoVE Bioengineering
Solid-phase Submonomer Synthesis of Peptoid Polymers and their Self-Assembly into Highly-Ordered Nanosheets
Molecular Foundry, Lawrence Berkeley National Laboratory
A simple and general manual peptoid synthesis method involving basic equipment and commercially available reagents is outlined, enabling peptoids to be easily synthesized in most laboratories. The synthesis, purification and characterization of an amphiphilic peptoid 36mer is described, as well as its self-assembly into highly-ordered nanosheets.
JoVE Clinical and Translational Medicine
Bilateral Common Carotid Artery Occlusion as an Adequate Preconditioning Stimulus to Induce Early Ischemic Tolerance to Focal Cerebral Ischemia
There is accumulating evidence, that ischemic preconditioning (PC) – a non-damaging ischemic challenge to the brain - confers a transient protection to a subsequent damaging ischemic insult. We established bilateral common carotid artery occlusion (BCCAO) as a preconditioning stimulus to induce early ischemic tolerance (IT) to transient focal cerebral ischemia (induced by middle cerebral artery occlusion, MCAO) in C57Bl6/J mice.
JoVE Clinical and Translational Medicine
Modeling Colitis-Associated Cancer with Azoxymethane (AOM) and Dextran Sulfate Sodium (DSS)
Division of Gastroenterology, Washington University School of Medicine
We demonstrate a protocol in which administration of the genotoxic agent azoxymethane (AOM) followed by three cycles of the pro-inflammatory agent dextran sulfate sodium (DSS) rapidly and consistently generates colon tumors in mice with morphologic and molecular similarities to those seen in human colitis-associated cancer.
JoVE General
High-resolution Measurement of Odor-Driven Behavior in Drosophila Larvae
Laboratory of Neurogenetics and Behavior, Rockefeller University
In this video article, we describe a new method allowing the construction of odorant gradients with stable and controllable geometries. We briefly illustrate how these gradients can be used to screen for olfactory defects (full and partial anosmia) and to study more subtle features of chemotaxis behavior.
JoVE Neuroscience
Single Sensillum Recordings in the Insects Drosophila melanogaster and Anopheles gambiae
Laboratory of Neurogenetics and Behavior, Rockefeller University
Electrophysiological responses of olfactory sensory neurons to odorants can be measured in insects using single sensillum recordings. In this video article we will demonstrate how to perform single sensillum recordings in the antennae of the vinegar fly (Drosophila melanogaster) and the maxillary palps of the malaria mosquito (Anopheles gambiae).
JoVE Neuroscience
Calcium Imaging of Odor-evoked Responses in the Drosophila Antennal Lobe
1Center for Integrative Genomics, University of Lausanne, 2Department of Biology, University of Konstanz
We describe an established technique to measure and analyze odor-evoked calcium responses in the antennal lobe of living Drosophila melanogaster.
JoVE Neuroscience
Imaging Odor-Evoked Activities in the Mouse Olfactory Bulb using Optical Reflectance and Autofluorescence Signals
This article presents the protocols of intrinsic optical signals and flavoproteins autofluorescence signals imaging to map odor-evoked activities at the surface of the olfactory bulb in mice.
JoVE Neuroscience
A Molecular Readout of Long-term Olfactory Adaptation in C. elegans
1Department of Biological Sciences and Institute for Neuroscience, George Washington University, 2Fred Hutchinson Cancer Research Center, 3Department of Cell and Tissue Biology, University of California San Francisco
Here we describe a molecular readout of long-term olfactory adaptation in Caenorhabditis elegans. The Protein Kinase G, EGL-4, is necessary for stable adaptation responses in the primary sensory neuron pair called AWC. During prolonged odor exposure EGL-4 translocates from the cytosol to nucleus of the AWC.
JoVE Neuroscience
Post-embedding Immunogold Labeling of Synaptic Proteins in Hippocampal Slice Cultures
1Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 2Department of Microbiology and Molecular Genetics, Medical College of Wisconsin
The localization and distribution of proteins provide important information for understanding their cellular functions. The superior spatial resolution of electron microscopy (EM) can be used to determine the subcellular localization of a given antigen following immunohistochemistry. For tissues of the central nervous system (CNS), preserving structural integrity while maintaining antigenicity has been especially difficult in EM studies. Here, we adopt a procedure that has been used to preserve structures and antigens in the CNS to study and characterize synaptic proteins in rat hippocampal CA1 pyramidal neurons.
JoVE Clinical and Translational Medicine
Modeling Intracerebral Hemorrhage in Mice: Injection of Autologous Blood or Bacterial Collagenase
1Department of Physiology and Pharmacology, Loma Linda University School of Medicine, 2College of Natural and Agricultural Sciences, University of California, Riverside, 3Department of Anesthesiology, Loma Linda University School of Medicine, 4Department of Neurosurgery, Loma Linda University School of Medicine
Clinically relevant animal models of intracerebral hemorrhage (ICH) are needed to extend our knowledge of hemorrhagic stroke and to examine novel therapeutic strategies. In this study, we describe and evaluate two ICH models that implement unilateral injections of either autologous whole blood or bacterial collagenase into the basal ganglia (corpus striatum) of mice.
JoVE Immunology and Infection
Assessing Hepatic Metabolic Changes During Progressive Colonization of Germ-free Mouse by 1H NMR Spectroscopy
1School of Chemistry, Food and Pharmacy, The University of Reading, 2Department of Nutritional Sciences, The University of Reading
A progressive colonization procedure is described to further assess its impact on the host hepatic metabolism. Colonization is monitored non invasively by evaluating the urinary excretion of microbial co-metabolites by NMR-based metabolic profiling while hepatic metabolism is assessed by High Resolution Magic Angle Spinning (HR MAS) NMR profiling of intact biopsy.
JoVE Applied Physics
Atom Probe Tomography Studies on the Cu(In,Ga)Se2 Grain Boundaries
1Department of Microstructure Physics and Alloy Design, Max-Planck-Institut für Eisenforschung GmbH, 2Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg ( ZSW )
In this work, we describe the use of the atom-probe tomography technique for studying the grain boundaries of the absorber layer in a CIGS solar cell. A novel approach to prepare the atom probe tips containing the desired grain boundary with a known structure is also presented here.
JoVE Neuroscience
Lateral Fluid Percussion: Model of Traumatic Brain Injury in Mice
1Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, 2Spinal Cord and Brain Injury Research Center, 3Department of Anatomy and Neurobiology, Department of Physical Medicine and Rehabilitation, University of Kentucky Chandler Medical Center
Lateral fluid percussion (LFP), an established model of traumatic brain injury in mice, is demonstrated. LFP fulfills three major criteria for animal models: validity, reliability and clinical relevance. The procedure, consisting of surgical craniotomy, fixation of hub followed by induction of injury, resulting in focal and diffuse injuries, is described.
More Results...
