permeability Protocols

Category: Staining Protocols: Gram Staining Protocols

Gram-positive and Gram-negative organisms form a complex of crystal violet and iodine within the bacterial cell during the Gram-staining procedure. Gm+ organisms are thought to resist decolorization by alcohol or acetone because cell wall permeability is markedly decreased when it is dehydrated by these solvents. Thus, the dye complex is entrapped within the cell, resist being washed out by the solvents, and Gm+ bacteria remain purple following this differential stain. - [Read Gram Staining Protocol]

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

Membrane permeability of perfused cell cultures, as determined by the efflux of [3H]-2-deoxy-D-glucose-6phosphate, is used as an indicator of the cytotoxic effect of chemicals. - [Read Membrane Permability as a Measure of Cytotoxcity in Perfused Cell Cultures]

Category: Transfection Protocols

Protocol describes transfection of plasmid DNA into mammalian cell lines using electroporation, a process whereby external application of electric pulses induce cell membrane permeability. Cells in suspension and small volume cells are difficult to transfect, whereas adherent cells and large volume cells are relatively easy. Regardless of cell size or phenotype, transfection efficiency increases with a high concentration of cells in a small volume. - [Read Optimizing Electrotransfection of Mammalian Cells In Vitro Protocol]

Category: Transfection Protocols: Electroporation Sonoporation Protocols

Protocol describes transfection of plasmid DNA into mammalian cell lines using electroporation, a process whereby external application of electric pulses induce cell membrane permeability. A number of factors can affect electrotransfection efficiency. In general, cells in suspension and small volume cells are difficult to transfect, whereas adherent cells and large volume cells are relatively easy. - [Read Optimizing Electrotransfection of Mammalian Cells In Vitro Protocol]

Category: Plant Biology Protocols: Plant Proteins, Peptides and Antigens

The activity of ß-glucuronidase (GUS) can be accurately determined in intact plant tissue using 4-methylumbelliferyl ß-D-glucuronide (4-MUG) as a substrate. Upon hydrolysis by GUS, the fluorochrome 4-methyl umbelliferone (4-MU) is produced. This method is based on the permeability of both 4-MUG and 4-MU through plant tissue. It consists of incubation of the tissue with the reagent and quantification of the fluorescence emitted by 4-MU in the solution. GUS activity in each sample can be... - [Read Quantitative GUS Activity Assay in Intact Plant Tissue Protocol]