high Protocols

Category: DNA Protocols: Cosmid Library Protocols

Unamplified cosmid libraries are plated at high density onto 150-mm nitrocellulose or nylon filters and screened by hybridization - [Read Screening an Unamplified Cosmid Library by Hybridization: Plating the Library onto Filters Protocol]

Category: Cell Biology and Cell Culture: Flow Cytometry Protocols: DNA Staining Protocols for Flow Cytometry

In an attempt to accurately measure DNA content with simultaneous preservation of cell surface markers, we have utilized gentle ethanol treatment techniques, which permeablize cells with minimal loss of surface antigen expression and antibody-antigen association. For some cell types, the presence of apoptotic cells based on reduced DNA content can also be detected. One such technique employs the addition of ethanol to cells previously resuspended in high concentrations of fetal bovine serum... - [Read Simultaneous Analysis of DNA Content and Surface Immunophenotype Protocol]

Category: DNA Protein Interactions Protocols: Electrophoretic Mobility Shift Assays EMSA Protocols

The target sequence is simultaneously labeled and amplified, then heat-denatured and resolved by non-denaturing polyacrylamide gel electrophoresis.  Differences in sequence alter the conformation of the DNA and hence its electrophoretic mobility and, because of the high resolution of polyacrylamide gels, most conformational changes caused by subtle changes in sequence can be detected. - [Read Single-Strand Conformation Polymorphism Analysis Protocol]

Category: Mass Spectrometry Protocols

The dried-droplet method will fail for samples containing significant concentrations of involatile solvents or high concentrations of salts. PROWL - [Read Slow crystallization Protocol for MALDI samples]

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

Describes how FACSort can be used to enrich for transfected mouse cells expressing high levels of the human thrombin receptor. The sorted fraction can then be cultured in vivo and reanalyzed 12 days later to show that it remains enriched for thrombin receptor-expressing cells. - [Read Sorting Transfected Cells Based on Gene Expression, Followed by Culture in Vivo]

Category: Nucleic Acid Detection Protocols: Nucleic Acid Blotting Protocols

Protocol for southern blotting: simultaneous transfer of DNA from a single agarose gel to two membranes. DNA can be simultaneously transferred from opposite sides of a single agarose gel to two membranes.  Bidirectional transfer occurs rapidly at first, but soon slows down as the gel becomes dehydrated.  Because the efficiency of transfer is low, the method works best when the target sequences are present in high concentration - [Read Southern Blotting: Simultaneous Transfer of DNA from a Single Agarose Gel to Two Membranes Protocol]

Category: Nucleic Acid Detection Protocols: Nucleic Acid Blotting Protocols

Protocol for southern hybridization of radiolabeled probes to nucleic acids immobilized on membranes. Protocol describes how to carry out Southern hybridizations at high stringency in phosphate-SDS buffers.  Although a wide variety of formats are available, most Southern hybridizations are carried out in heat-sealable bags, roller bottles, or plastic boxes. - [Read Southern Hybridization of Radiolabeled Probes to Nucleic Acids Immobilized on Membranes Protocol]

Category: Microscopy Protocols: In Vivo Imaging Protocols

Sophisticated fluorescence microscopy methods & equipment, now allow cellular events to be studied at high resolution in living material. The studying of living fly tissues presents unique difficulties in keeping the cells alive, introducing fluorescent probes, & imaging through thick hazy cytoplasm. This protocol outlines the preparation of major tissue types amenable to study by time-lapse cinematography and different methods for keeping them alive. - [Read Time-Lapse Cinematography in Living Drosophila Tissues: Preparation of Material]

Category: Cytogenetics Protocols: In Situ Hybridization Protocols

This protocol fixes and prepares embryos for in situ hybridization to visualize transcript expression patterns. It is a modification of the method developed by Tautz and Pfeifle for whole-mount in situ analysis of embryos. Use of the standard hybridization protocol on RNAi-treated embryos results in high background staining, which makes visualization of transcript expression patterns practically impossible. The following modifications eliminate this problem and allow visualization of transcript. - [Read Transcript In Situ Hybridization of Whole-Mount Embryos for Phenotype Analysis of RNAi-Treated]

Category: Transfection Protocols

DEAE-dextran is generally used to obtain a burst of transient expression of cloned genes after transfection of mammalian cells. Many variants of the technique have been described, all of which seek to maximize the uptake of DNA and to minimize the cytotoxic effects of DEAE-dextran. In this protocol cells are exposed briefly to a high concentration of DEAE-dextran-DNA and then to chloroquine diphosphate, which is a facilitator of transfection. - [Read Transfection Mediated by DEAE-Dextran: High-efficiency Method Protocol]

Category: Transfection Protocols: Electroporation Sonoporation Protocols

Electrocompetent bacteria are prepared by growing cultures to mid-log phase, washing the bacteria extensively at low temperature, and then resuspending them in a solution of low ionic strength containing glycerol. DNA is introduced during exposure of the bacteria to a short high-voltage electrical discharge.

Category: Protein Protocols: Western Blot Protocol: Troubleshooting Western Blots

Troubleshooting Guide for Chemiluminescent Western Blotting Pierce. High Background, Reverse image on film, Blot glows in the darkroom, Signal duration is less than 8 hours, Weak or no signal, Spots within the protein bands, non-specific bands. - [Read Troubleshooting Guide for Chemiluminescent Western Blotting Pierce]

Category: Protein Protocols: Immunoprecipitation Protocols: Immunoprecipitation Troubleshooting

Troubleshooting the immunoprecipitation procedure Roche. Tagged proteins not visible or only weakly visible on Western blot. High background or many nonspecific bands on gel or blot membrane. - [Read Troubleshooting the immunoprecipitation procedure IP and IB - Roche]

Category: Yeast Protocols: Yeast Two-Hybrid Systems Protocols

High Efficiency Transformation of a yeast strain requiring maintenance of a plasmid. - [Read Two Hybrid System Transformation Protocol]

Category: DNA Protocols: cDNA Library Protocols: cDNA Library Construction Protocols

PCR is used as a preparative tool for the synthesis of a high-complexity double-stranded DNA library. In the example presented here, a mixture of synthetic oligonucleotides is used to synthesize a random peptide NNK library, where K is either T or G. The exclusion of A and C nucleotides at the third position decreases the occurrence of stop codons but still allows codons for all 20 amino acids. - [Read Use of PCR to Prepare a Double-Stranded DNA Library Encoding Random Peptides Protocol]

Category: Microscopy Protocols: Optical Microscopy Protocols

The light microscope allows dynamic biological processes to be imaged in their native (i.e., aqueous) environment with relatively high temporal resolution. However, the diffraction-limited resolution is low. When working at or beyond the diffraction-limited resolution of the LM, a disadvantage of fluorescence imaging is the relatively low signal-to-noise (S/N) ratio of the images. However, this can be increased significantly by video and computer technology. - [Read Watching Molecular Motors at Work by Video-Enhanced Light Microscopy]

Category: Yeast Protocols: Yeast Transformation Protocols: High Efficiency Yeast Transformation Protocols

Protocol for high efficiency Yeast transformation. - [Read Yeast Transformation (high efficiency) Protocol]