features Protocols

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

Analysis of DNA Fragmentation Using Agarose Gel Electrophoresis Shailaja Kasibhatla et al. This protocol provides a qualitative method for assessing cell death by detecting DNA fragments using agarose gel electrophoresis. One of the classic features of apoptosis is the cleavage of the genomic DNA into oligonucleosomal fragments represented by multiples of 180-200 bp. Visualizing these fragments can aid in characterizing an apoptotic event. May be combined with more quantitative methods. - [Read Analysis of DNA Fragmentation Using Agarose Gel Electrophoresis (Subscription Required)]

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: PCR Protocols

Method describes how to modify the termini of PCR products by introducing restriction sites and other features.  To reduce the chance of contamination with exogenous DNAs, prepare and use a special set of reagents and solutions for PCR only.  Bake all glassware for 6 hours at 150°C and autoclave all plasticware. - [Read Genetic Engineering with PCR Protocol]

Category: PCR Protocols: PCR Optimization

Method describes how to modify the termini of PCR products by introducing restriction sites and other features.  To reduce the chance of contamination with exogenous DNAs, prepare and use a special set of reagents and solutions for PCR only.  Bake all glassware for 6 hours at 150°C and autoclave all plasticware. - [Read Genetic Engineering with PCR Protocol]

Category: Cell Biology and Cell Culture: Flow Cytometry Protocols: Cell Cycle Analysis Protocols

Exponentially growing cells are asynchronous with respect to the cell cycle stage. Detection of cell cycle-related events is improved by enriching the culture for cells at the stage during which the particular event occurs. Methods for synchronizing cells are provided here, including those based on morphological features of the cell. - [Read Methods for Synchronizing Cells at Specific Stages of the Cell Cycle]

Category: Chromatography Protocols: Affinity Chromatography Protocols

Recombinant proteins engineered to have a polyhistidine tail at either the carboxyl or amino terminus can easily be purified in one step by affinity chromatography on a resin carrying chelated nickel ions.  Chromatography can be carried out in column or batch formats.  After unbound proteins are washed away, the target protein is eluted using imidazole, which typically preserves the antigenic and functional features of the protein. - [Read Purification of Histidine-tagged Proteins by Immobilized Ni2+ Absorption Chromatography Protocol]