[Low transfecting efficiency of phage lambda ring chromosomes and their fragments formed by membrane nucleases]

Transfection efficiency of a number of lambda DNA samples differing in ring to linear molecules ratio was determined. Graphic extrapolation to the zero content of linear molecules showed that efficiency of ring molecules did not exceed 5% of that of linear molecules. Probably, this difference is caused by more fast penetration of linear molecules into the cell and, therefore, by lower probability of their degradation by cell wall nucleases. Fragments of both ring and linear molecules formed by cell wall nucleases proved to be inactive in marker rescue experiments.