Studies of DNA-infected disrupted cell preparations.

Procedures for increasing both sensitivity and reproducibility of virus production in disrupted DNA-infected cell preparations have been described. A variety of chemical agents and physical procedures, including fractionation by centrifugation, were tested for effects on the ability of disrupted cell preparations to form virus particles. DNA prepared from lambda-virulent phage, a deletion mutant derived from lambda-temperate phage, was shown to be infectious in disrupted cell preparations. When infectious lambda-virulent and lambda-temperate phage DNA were added simultaneously to frozen and thawed cell preparations, a marked increase in the production of infectious units was observed. This effect was eliminated when the biological activity of either DNA type was destroyed by heat. Phage particles produced by such mixed infections had the same buoyant density as the respective parental phages.