[Comparative study of chromosome and plasmid transformation in Bacillus subtilis: the effect of lysozyme and polyethylene glycol].

The influence of lysozyme and polyethyleneglycol (PEG) on chromosomal and plasmid transformation was comparatively investigated. Treatment of competent cell culture with low concentrations of lysozyme which do not affect cell viability stimulates both types of transformation. When transforming DNA was treated with definite concentrations of PEG, inhibition of transformation using chromosomal DNA occurred. The similar treatment, however, stimulated transformation by oligomeric forms of plasmid DNA. Possibly, PEG alters the DNA conformation rendering it less sensitive to nuclease degradation. This promotes plasmid transformation but reduces the frequency of transformation by chromosomal DNA, because the changes resulting from nuclease action further DNA integration into the genome of a recipient.