We demonstrate the fabrication of a low-cost cryogenic stage designed to fit most reflected light microscopes. This lab-built cryogenic stage enables efficient and reliable correlative imaging between cryo-light and cryo-electron microscopy.
Determination of Molecular Structures of HIV Envelope Glycoproteins using Cryo-Electron Tomography and Automated Sub-tomogram Averaging
1Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 2The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, 3National Library of Medicine, National Institutes of Health, 4Massachusetts Institute of Technology, 5William Fremd High School, 6University of Virginia, 7Duke University, 8Yale University, 9University of Notre Dame, 10Washington University in St. Louis, 11Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12Thomas Jefferson High School for Science and Technology
The protocol describes a high-throughput approach to determining structures of membrane proteins using cryo-electron tomography and 3D image processing. It covers the details of specimen preparation, data collection, data processing and interpretation, and concludes with the production of a representative target for the approach, the HIV-1 Envelope glycoprotein. These computational procedures are designed in a way that enables researchers and students to work remotely and contribute to data processing and structural analysis.
Visualizing Proteins and Macromolecular Complexes by Negative Stain EM: from Grid Preparation to Image Acquisition
Visualizing protein samples by negative stain electron microscopy (EM) has become a popular structural analysis method. It is useful for quantitative structural analysis, such as calculating a 3D reconstruction of the molecules being studied, and also for qualitative examination of the quality of protein preparations. In this article we present detailed protocols for preparing the EM grids, staining the sample and visualizing the sample in an electron microscope. Novice users can follow these protocols easily and to utilize negative stain EM as a routine assay, in addition to other biochemical assays, for evaluating their protein samples.
Structure of HIV-1 Capsid Assemblies by Cryo-electron Microscopy and Iterative Helical Real-space Reconstruction
This article describes a method to obtain a three-dimensional (3D) structure of helically assembled molecules using cryo-electron microscopy. In this protocol, we use HIV-1 capsid assemblies to illustrate the detailed 3D reconstruction procedure for achieving a density map by the iterative helical real-space reconstruction method.
Single Particle Electron Microscopy Reconstruction of the Exosome Complex Using the Random Conical Tilt Method
This article describes a standard method to get a three-dimensional (3D) reconstruction of biological macromolecules using negative staining electron microscopy (EM). In this protocol, we explain how to get the 3D structure of the Saccharomyces cerevisiae exosome complex at medium resolution using the random conical tilt reconstruction method (RCT).
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.
Evaluation of Polymeric Gene Delivery Nanoparticles by Nanoparticle Tracking Analysis and High-throughput Flow Cytometry
1Biomedical Engineering Department, Johns Hopkins University School of Medicine, 2Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, 3Wilmer Eye Institute, Johns Hopkins University School of Medicine, 4Institute for Nanobiotechnology, Johns Hopkins University School of Medicine
A protocol for nanoparticle tracking analysis (NTA) and high-throughput flow cytometry to evaluate polymeric gene delivery nanoparticles is described. NTA is utilized to characterize the nanoparticle particle size distribution and the plasmid per particle distribution. High-throughput flow cytometry enables quantitative transfection efficacy evaluation for a library of gene delivery biomaterials.
We illustrate here how to use electron cryotomography (ECT) to study the ultrastructure of bacterial cells in near-native states, to "macromolecular" (~4 nm) resolution.
Plant viral nanoparticles (VNPs) are promising platforms for applications in biomedicine. Here, we describe the procedures for plant VNP propagation, purification, characterization, and bioconjugation. Finally, we show the application of VNPs for tumor homing and imaging using a mouse xenograft model and fluorescence imaging.
1Laboratory of Nano- and Translational Medicine, Department of Radiation Oncology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, 2Carolina Center for Nanotechnology Excellence, University of North Carolina
This article describes a nanoprecipitation method to synthesize polymer-based nanoparticles using diblock co-polymers. We will discuss the synthesis of diblock co-polymers, the nanoprecipitation technique, and potential applications.
1Organic Chemistry Institute and CeNTech, Westfälische Wilhelms-Universität Münster, 2Laboratory of Macromolecular and Organic Chemistry, Institute for Complex Molecular Systems, Eindhoven University of Technology, 3Laboratory of Materials and Interface Chemistry and Soft Matter Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology
The goal of this experiment is to determine and control the size, shape and stability of self-assembled discotic amphiphiles in water. For aqueous based supramolecular polymers such level of control is very difficult. We apply a strategy using both repulsive and attractive interactions. The experimental techniques applied to characterize this system are broadly applicable.
Assessing Two-dimensional Crystallization Trials of Small Membrane Proteins for Structural Biology Studies by Electron Crystallography
Evaluating two-dimensional (2D) crystallization trials for the formation of ordered membrane protein arrays is a highly critical and difficult task in electron crystallography. Here we describe our approach in screening for and identifying 2D crystals of predominantly small membrane proteins in the range of 15 – 90kDa.
Here, we describe a protocol for the purification of highly active Hsp104, a hexameric AAA+ protein from yeast, which couples ATP hydrolysis to protein disaggregation. This scheme exploits a His6-tagged construct for affinity purification from E. coli followed by anion-exchange chromatography, His6-tag removal with TEV protease, and size-exclusion chromatography.
An approach for analyzing migration and eventual fate of avian neural crest cells in quail-chick chimeric embryos is described. This method is a simple and straightforward technique for tracing neural crest cells during migration and differentiation that are otherwise difficult to distinguish within an unmanipulated chick embryo.
Reproducible Mouse Sciatic Nerve Crush and Subsequent Assessment of Regeneration by Whole Mount Muscle Analysis
In this report we describe a method to crush mouse sciatic nerve. This method uses readily available hemostatic forceps and easily and reproducibly produces complete sciatic nerve crush. In addition, we describe a method to prepare muscle whole mounts suitable for analysis of nerve regeneration after sciatic nerve crush.
Here are some highlights from the December 2011 Issue of Journal of Visualized Experiments (JoVE).
The plant cuticle is a waxy outer covering on plants that has a primary role in water conservation but is also an important barrier against the entry of pathogenic microorganisms. In this video, we demonstrate the analysis of plant cuticle mutants identified by forward and reverse genetics approaches.
A method for embedding yeast colonies allowing sectioning for light and electron microscopy. This protocol allows determination of the distribution of sporulated cells and pseudohyphal cells within colonies providing a new tool toward understanding the organization of cell types within a fungal community.
This study describes a method that allows the rapid and clear diagnosis of plant virus diseases in about half a day by using a combination of microwave assisted plant sample preparation for transmission electron microscopy and negative staining methods.
Correlative Light and Electron Microscopy (CLEM) as a Tool to Visualize Microinjected Molecules and their Eukaryotic Sub-cellular Targets
The CLEM technique has been adapted to analyze ultrastructural morphology of membranes, organelles, and subcellular structures affected by microinjected molecules. This method combines the powerful techniques of micromanipulation/microinjection, confocal fluorescent microscopy, and electron microscopy to allow millimeter to multi-nanometer resolution. This technique is amenable to a wide variety of applications.
1Department of Ophthalmology and Visual Sciences, University of Iowa, 2Omics Laboratory, University of Iowa, 3School of Dentistry, UCLA, 4Bernard and Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, College of Physicians and Surgeons, Columbia University
The dissection technique illustrates enucleation of the mouse eye for tissue fixation to perform phenotyping in high-throughput screens.
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.
Harvesting and Cryo-cooling Crystals of Membrane Proteins Grown in Lipidic Mesophases for Structure Determination by Macromolecular Crystallography
Herein is described procedures implemented in the Caffrey Membrane Structural and Functional Biology Group to harvest and cryo-cool membrane protein crystals grown in lipidic cubic and sponge phases for use in structure determination using macromolecular X-ray crystallography.
This protocol describes how resin embedded brain tissue can be prepared and imaged in the three dimensions in the focussed ion beam, scanning electron microscope.
Quantifying Glomerular Permeability of Fluorescent Macromolecules Using 2-Photon Microscopy in Munich Wistar Rats
A technique utilizing high resolution intavital 2-photon microscopy to directly visualize and quantify gloemrular filtration in surface glomeruli. This method allows for direct determination of permeability characteristics of macromolecules in both normal and diseased states.
Revealing Dynamic Processes of Materials in Liquids Using Liquid Cell Transmission Electron Microscopy
We have developed a self-contained liquid cell, which allows imaging through liquids using a transmission electron microscope. Dynamic processes of nanoparticles in liquids can be revealed in real time with sub-nanometer resolution.
1Department of Pathology, Medical College of Wisconsin, 2Current Address: Department of Pathology, Wayne State University School of Medicine Detroit Medical Center, 3Department of Neurology, Medical College of Wisconsin, 4Department of Medicine, Medical College of Wisconsin, 5Division of Neoplastic Diseases and Related Disorders, Medical College of Wisconsin
Fat pad aspiration is a preferred, minimally invasive, and low cost approach as compared to other methods to detect amyloid for diagnosis of systemic amyloidosis. This video article demonstrates a procedural outline for performing fat pad aspiration with appropriate processing of the specimen for the optimal diagnostic outcome.
We describe a protocol for transcardiac perfusion of mice, removal and sectioning of the brain, as well as immunoperoxidase staining, resin embedding, and ultrathin sectioning of the brain sections. Upon completion of these procedures, the immunostained material is ready for examination with transmission electron microscopy.
RNA In situ Hybridization in Whole Mount Embryos and Cell Histology Adapted for Marine Elasmobranchs
By combining methods for RNA whole mount in situ hybridization and histology, gene expression can be linked with cell fate decisions in the developing embryo. These methods have been adapted to marine elasmobranchs and facilitate the use of these animals as model organisms for biomedical, toxicology and comparative studies.
Synthesis, Assembly, and Characterization of Monolayer Protected Gold Nanoparticle Films for Protein Monolayer Electrochemistry
Alkanethiolate stabilized gold colloids known as monolayer protected clusters (MPCs) are synthesized, characterized, and assembled into thin films as an adsorption interface for protein monolayer electrochemistry of simple redox protein like Pseudomonas aeruginosa azurin (AZ) and cytochrome c (cyt c).
Generation of an Immortalized Murine Brain Microvascular Endothelial Cell Line as an In Vitro Blood Brain Barrier Model
This method describes how to isolate and immortalize microvascular endothelial cells from mouse brain. We describe a step-by-step protocol starting from the homogenization of brain tissue, digestion steps, seeding and immortalization of the cells. Usually, it takes about five weeks to obtain a homogenous, immortalized microvascular endothelial cell line.
Intraoperative Detection of Subtle Endometriosis: A Novel Paradigm for Detection and Treatment of Pelvic Pain Associated with the Loss of Peritoneal Integrity
1Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Greenville Hospital System, 2Department of Pathology, Duke University Health System, 3Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Duke University
Loss of peritoneal integrity provides a new paradigm to understand and treat chronic pelvic pain in women with mild forms of endometriosis and can be easily detected using intraoperative instillation of dye at the time of laparoscopy.
The intraluminal middle cerebral occlusion model in mice is herein presented. The extent of cerebral infarct is evaluated by a neurologic score and cresyl violet staining, an alternative staining to TTC, offering the great advantage to test in parallel many interest markers.
Neural induction is the first step in the formation of the brain. It is a mechanism by which Hensen's node (organizer), instructs adjacent tissue to adopt a neural fate, i.e. to give rise to the nervous system. This video demonstrates an assay for neural induction in chick embryo.
1Institute of Medical Microbiology and Hygiene, University of Lübeck, 2Institute of Anatomie, University of Lübeck, 3Department of Obstetrics and Gynecology, University Hospital of Schleswig-Holstein, University of Lübeck, 4Medical Clinic III, University Hospital of Schleswig-Holstein, University of Lübeck
We describe an ex vivo infection model for visualisation of direct interactions from bacterial pathogens with human fallopian tube cells. The whole organ tissue model was established to investigate C. trachomatis induced pathology to the female fallopian tube under "life-like" conditions.
FM dyes have been of invaluable help in the understanding of synaptic dynamics. FMs are normally followed under the fluorescent microscope during different stimulation conditions. However, photoconversion of FM dyes combined with electron microscopy allows the visualization of distinct synaptic vesicle pools, among other ultrastructure components, in synaptic boutons.
Here are some highlights from the October 2011 Issue of Journal of Visualized Experiments (JoVE).
Simple and reproducible procedures are described for making three structurally distinct collagen assemblies from a common commercially available Type I collagen monomer. Native type, fibrous long spacing or segmental long spacing collagen can be constructed by varying the conditions to which the 300 nm long and 1.4 nm diameter monomer building block is exposed.
Single-cell electroporation (SCE) is a specialized technique allowing delivery of DNA or other macromolecules into individual cells within intact tissue, including in vivo preparations. Here we detail the procedure for SCE of a fluorescent dye or plasmid DNA into neurons within the intact brain of the Xenopus laevis tadpole.
This paper demonstrates methods for the isolation, purification and detection of exosomes, as well as techniques for analysis of their molecular content. These methods are adaptable for exosome isolation from both cell culture media and biological fluids, and can beyond analysis of molecular content also be useful in functional studies.
This video demonstrates New culture, a method by which chick embryos are cultured outside the egg for up to 24 hr. This method enables one to study early development (primitive streak to 14 som.), a period corresponding to E7-9 in mouse. Applications of this technique include electroporation, in situ hybridization and immunohistochemistry.
This video demonstrates whole mount immunohistochemistry, a method by which the spatial and temporal expression pattern of an antigen can be visualized in young chick embryos. This method was originally introduced by Jane Dodd and Tom Jessell.
Identification of mechanisms underlying muscle damage is crucial. Here we present the histological technique for preparing paraffin-embedded and frozen sections of Drosophila thoracic muscles. This allows analysis of muscle morphology and localization of protein and other muscle cell components.
A rotating cell culture system that allows epithelial cells to grow under physiological conditions resulting in 3-D cellular aggregate formation is described. The aggregates generated display in vivo-like characteristics not observed in conventional culture models and serve as a more accurate organotypic model system for a multitude of scientific investigations.
The fabrication of electrically addressable, high-aspect-ratio (> 1000:1) metal nanowires separated by gaps of single nanometers using either sacrificial layers of aluminum and silver or self-assembled monolayers as templates is described. These nanogap structures are fabricated without a clean room or any photo- or electron-beam lithographic processes by a form of edge lithography known as nanoskiving.
Here are some highlights from the July 2011 Issue of Journal of Visualized Experiments (JoVE).
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.
Neutrophil Extracellular Traps (NETs) are an important innate immune mechanism to fight pathogenic bacteria, fungi and parasites. Here we describe methods to isolate neutrophil granulocytes from human blood and to activate them to form NETs. We present preparation techniques to visualize NETs in light and electron microscopy.
1Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, 2Clinical Research Laboratory, 81st Medical Group, Keesler Air Force Base
Lytic phage biosensors and antibody beads are able to discriminate between methicillin resistant (MRSA) and sensitive staphylococcus bacteria. The phages were immobilized by a Langmuir-Blodgett method onto a surface of a quartz crystal microbalance sensor and worked as broad range staphylococcus probes. Antibody beads recognize MRSA.
The zebrafish kidney is home to both renal and hematopoietic adult stem/progenitor cells, and represents an outstanding opportunity to study these cell types and their progeny in a vertebrate model organism. Here, we demonstrate a detailed dissection procedure that enables the researcher to identify and surgically remove the adult zebrafish kidney, which can be used for applications such as cell isolation, transplantation, and expression studies of kidney and/or blood cell populations.