Two potentialobstacles to using agarose gel electrophoresis for the fractionation of viruses and related particles are: (a) adherence of the sample to the gel during electrophoresis, and (b) the prolonged procedures necessary for determining whether or not particles stained with nucleic acid‐specific stains have their nucleic acid in a packaged state. It is demonstrated that adherence of positively charged tail fibers of bacteriophage T7 to agarose gels is the probable cause of a previously described (Serwer, P. and Pichler, M. E., J. Virol. 1978, 28, 917–928) sample concentration‐dependent spreading of bands formed by bacteriophage T7 during agarose gel electrophoresis (concentration effect). Procedures for screening preparations of agarose for nonadherence of particles are described and use of these procedures has resulted in the finding that the concentration effect is decreased or eliminated for T7 in preparations of agarose designed for low electro‐osmosis. In addition, it has been shown that after electrophoresis, the intensity with which bacteriophage T7 (and other DNA bacteriophages) stains with the nucleic acid‐specific stain, ethidium bromide, is increased by ejecting DNA from the interior of T7; this increase in staining intensity is used to recognized bands formed by particles with packaged DNA.
ASJC Scopus subject areas
- Clinical Biochemistry