DNA for analysis is purified using salt precipitation. The method is gentle, limits the breakage of the long chromosomal strands, and avoids the use of phenol and chloroform. It is suitable for use with cultured cells, breast tumor tissue that has been subjected to hormone receptor analysis, and blood samples. The loss of heterozygosity assay is performed using a multiplex PCR, in which one of each primer pair is labeled with a different fluorophor. - [Read A Multiplex PCR Method to Define a Narrow Deleted Chromosomal Region of a Tumor Genome]
Cryogenic preservation (storage below -100°C) of cell cultures is widely used to maintain backups or reserves of cells without the associated effort and expense of feeding and caring for them. The success of the freezing process depends on four critical areas: Proper handling and gentle harvesting of the cultures; Correct use of the cryoprotective agent; A controlled rate of freezing; Storage under proper cryogenic conditions. - [Read Cryogenic Preservation and Storage of Animal Cells Protocol]
Lysis in the sucrose-containing Buffer ("Mito-Buffer") is supposed to prevent accidential disrupture of the mitochondria to prevent the leakage of mitochondrial proteins (such as cytochrome c) into the cytosol. Celldeath.de - [Read Gentle lysis of mammalian cells for cytochrome c release assay]
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]
Fixation can mask epitopes. However, it is often possible to re-expose them using a gentle incubation with proteases, which removes obstructing structures and allows antibody access, as described here. Many proteases can be used for this procedure, including very crude preparations of proteases, such as pronase. However, using a better-characterized protease, such as trypsin, allows a more controlled reaction and better comparison between experiments. - [Read Unmasking Hidden Epitopes with Proteases Protocol]
Tubulin is polymerized into microtubules by incubating tubulin at 37°C with GTP. A nucleation seed is added when the purpose is to assay microtubule elongation. Tubulin can also be polymerized for the purposes of recycling the tubulin or labeling the microtubules with fluorescently labeled tubulin. Based on the protocol by Timothy Mitchison of Harvard University.