light Protocols

Category: Microbiology: Antibiotics Concentration in Media LB

Working concentrations and stock solutions and which antibiotics are light sensitive. Preparation of stock solutions and calculator tool to calculate concentrations for stock solutions. Practical Molecular Biology. - [Read Antibiotics. and Antibiotics Stock Calculator Tools]

Category: Drosophila Protocols

Enzyme-linked reagents give excellent sensitivity and use a simple light microscope for detection. A range of enzymes is available, but for staining in situ, horseradish peroxidase will suit most needs. Diaminobenzidine (DAB) is one of the most sensitive substrates for horseradish peroxidase. It yields an intense brown product that is insoluble in both water and alcohol. It can be made more sensitive by adding metal salts such as cobalt or nickel to the substrate solution. - [Read Antibody Addition to Drosophila Specimens and Detection Using Enzyme-Linked Reagents Protocol]

Category: Reporter Gene Assays: B-Galactosidase Assay Protocols

The assay for ß-galactosidase relies on the ability of the enzyme to catalyze the hydrolysis of ONPG (o-nitrophenyl-ß-D- galactopyranoside) to free o-nitrophenol, which absorbs light at 420 nm. In this protocol, extracts of cells transfected with a ß-galactosidase reporter plasmid are incubated with ONPG. - [Read Assay for ß-galactosidase in Extracts of Mammalian Cells]

Category: Reporter Gene Assays: Luciferase Assay Protocols

In this protocol, cells transfected with a luciferase reporter plasmid are lysed in a detergent-containing buffer. Luciferase in the extract catalyzes an oxidation reaction in which D-luciferin is converted to oxyluciferin, with production of light at 556 nm that can be quantified in a luminometer. - [Read Assay for Luciferase in Extracts of Mammalian Cells Protocol]

Category: Protein Protocols: Protein Quantitation Concentration Protocols: Bradford Protein Assay Protocols

Bradford Protein Assay Spectrophotometry.  Includes spectrophotometry information and the Bradford protein assay: A spectrophotometer or colorimeter makes use of the transmission of light through a solution to determine the concentration of a solute within the solution.  A spectrophtometer differs from a colorimeter in the manner in which light is separated into its component wavelengths.  A spectrophotometer uses a prism to separate light and a colorimeter uses filters. - [Read Bradford Protein Assay Spectrophotometry]

Category: Pharmacology and Toxicology Protocols: Cytotoxicity Protocols: Cytotoxicity Assays in Cell Culture Protocols

Human A431 cells and mouse 3T3 cells are exposed in culture to UV light both in the presence and absence of test compound.  Phototoxicity is expressed as a decrease in cell viability as determined by the MTT assay. - [Read Cell Culture Phototoxicity Test Protocol]

Category: Microscopy Protocols: Optical Microscopy Protocols

When imaging specimens in the optical microscope, differences in intensity and/or color create image contrast, which allows individual features and details of the specimen to become visible. Contrast is defined as the difference in light intensity between the image and the adjacent background relative to the overall background intensity. In general, a minimum contrast value of 0.02 (2 percent) is needed by the human eye to distinguish differences between the image and its background. - [Read Contrast in Optical Microscopy]

Category: Microscopy Protocols: Optical Microscopy Protocols

The visibility of the faint star light is enormously enhanced against a dark background. This principle is applied in darkfield (also called darkground) microscopy, a simple and popular method for making unstained transparent specimens clearly visible. Such objects often have refractive indices very close in value to that of their surroundings and are difficult to image in conventional brightfield microscopy. - [Read Darkfield Illumination]

Category: Microscopy Protocols: Electron Microscopy Protocols

Article describe the preparation of cells for correlative electron microscopy after live light microscopic observation of fluorescently labeled cytoskeletal proteins microinjected into the same cells. Since identification of cytoskeletal elements in electron microscopic preparations is an essential part of any correlative study, procedures for immunogold labeling of cytoskeletal components and for myosin S1 decoration of actin filaments are also described. - [Read Electron Microscopy of the Cytoskeleton of Cultured Cells]

Category: Cell Biology and Cell Culture: Flow Cytometry Protocols: Cell Sorting Protocols

Protocol describes how monocytes can be sorted from a lysed whole blood sample, and that cytospin preparations can be made for examination by light microscopy. - [Read Enrichment Of Monocytes For Morphological Study Protocol]

Category: Cell Biology and Cell Culture: Flow Cytometry Protocols

Flow cytometric analysis of gram-negative bacterial cells. Includes: Staining Conditions and FACSort Settings; Light Scatter Resolution on the BD FACSort; Bacterial Cell Resolution on the BD FACSort. - [Read Flow Cytometric Analysis of Gram-Negative Bacterial Cells]

Category: Cell Biology and Cell Culture: Flow Cytometry Protocols: Apoptosis Cytometry Protocols

Common methods applicable to flow cytometry make it possible to: (1) identify and quantify dead or dying cells, (2) reveal a mode of cell death (apoptosis or necrosis), and (3) study mechanisms involved in cell death. Gross changes in cell morphology and chromatin condensation, which occur during apoptosis, can be detected by analysis with laser light beam scattering. - [Read Flow Cytometry of Apoptosis Protocol]

Category: Cell Biology and Cell Culture: Flow Cytometry Protocols: Flow Cytometry Immunofluorescence Staining Protocols

Fluorescent dyes absorb light at certain wavelengths and in turn emit their fluorescence energy at a higher wavelength. Each dye has a distinct emission spectrum, which can be exploited for multicolor analysis. eBioscience antibodies are available conjugated to a wide variety of fluorochromes. - [Read Fluorescent Dyes for Flow Cytometric Analysis]

Category: Histology Protocols: Tissue Sample Sectioning

Frozen Sectioning and Tissue Sectioning for Electron Microscopy. Includes Tissue Processing for Transmission Electron Microscopy and Tissue Preservation for Light Microscopy. University of California UCSF Dept. Pathology Research. - [Read Frozen Sectioning and Tissue Sectioning for Electron Microscopy]

Category: Fungi Protocols: Neurospora Protocols

Information and tips on how to assay light responses in Neurospora. - [Read How to Assay Light Responses in Neurospora]

Category: Western Blot Protocols: Antigen Detection Methods Protocols

The blot is blocked to prevent nonspecific adsorption of the immunological reagents.  Antibodies are then bound to the proteins immobilized on the membrane, and the antigen is detected by labeling the antibodies with conveniently identified tags.  Common labeling methods for chemiluminescent detection include anti-immunoglobulin antibody-coupled enzymes such as horseradish peroxidase, which catalyzes the oxidation of luminol and in turn releases light. - [Read Immunoblotting: Antigen Detection Using Chemiluminescence Protocol]

Category: Immunohistochemistry Protocols: Antibody Staining Protocols

There are several strategies to visualize the antibody. For transmitted light microscopy, color development substrates for enzymes are often used. The antibody can be directly labeled with the enzyme. However, such a covalent link between an antibody and an enzyme might result in a loss of both enzyme and antibody activity. For these reasons several multistep staining procedures have been developed, where intermediate link antibodies are used. In this protocol use the Vectastain ABC-kit. - [Read Immunocytochemistry in Free-Floating Sections Protocol]

Category: Immunohistochemistry Protocols

Describes two methods for using the immunoperoxidase reaction to localize antigens at the electron microscope level; one for adherent cultured cells and one for tissue sections. The reaction conditions are first optimized at the light microscope level and then adapted for EM level observation. These methods allow for reliable detection of antigens at the cell surface, within the cell, and especially in membrane bounded organelles. - [Read Immunoperoxidase Methods for Localization of Antigens in Cultured Cells and Tissues]

Category: Fungi Protocols: Neurospora Protocols

Procedure for an in vitro system to analyze light signal transduction in Neurospora crassa - [Read In Vitro System to Analyze Light Signal Transduction in Neurospora crassa]

Category: Microscopy Protocols: Fluorescence Microscopy Protocols

Article presents an introduction to fluorescence microscopy. Includes: Fundamentals of Excitation and Emission; Stokes' Shift; Fading, Quenching, and Photobleaching; Fluorescence Light Sources; Filter Terminology; The Fluorescence Light Budget; Detecting Single Molecules. - [Read Introduction to Fluorescence Microscopy]

Category: Cell Biology and Cell Culture: Apoptosis Protocols: Apoptosis Analysis

Leukostat Staining of Cytospin Preparations to Detect Apoptosis. Shailaja Kasibhatla et al. Leukostat staining is used to visualize nuclear changes and apoptotic body formation that are characteristic of apoptosis. Cells are viewed under a light microscope and counted to quantify apoptosis. This protocol can be used both for cells that grow in suspension and for adherent cells. - [Read Leukostat Staining of Cytospin Preparations to Detect Apoptosis]

Category: Cell Biology and Cell Culture: Apoptosis Protocols

Detection of Fragmented DNA in Apoptotic Cells Embedded in LR White:Histochemical (LM) and Ultrastructural (EM). Goping et al 1999. - [Read Light and Electron Microscopy Detection of Apoptosis]

Category: Molecular Imaging: Light Microscopy

Types of light microscopy, Bright Field Microscopy, Using a bright field microscope, mounting on slides, adjusting the microscope, Care of the microscope, When to use bright field microscopy. David R. Caprette. Rice University. - [Read Light Microscopy]

Category: Molecular Imaging: Light Microscopy

Light Microscopy - Microscopes in Cell Biology. House Ear Institute. Fluorescence microscopy, Nomarski differential interference contrast, Comparison between phase contrast and interference contrast optical systems , Interference contrast, Phase contrast, Darkfield illumination, alignment of Kohler illumination system, Protocol for using oil immersion lenses, Use of immersion oil, Calculating the final magnification on the photomicrograph, vibration, The coverslip glass, Photomicroscopy. - [Read Light Microscopy - Microscopes in Cell Biology]

Category: Molecular Imaging: Light Microscopy

Ahmanson Center for Advanced Electron Microscopy and Imaging. Use of Semi-Thin Cryosections for Light Microscopy, Immunolabeling of Cryosections on Glass Slides, Problems with Autofluorescence. House Ear Institute - [Read Light Microscopy Techniques]