INDUCIBILITY OF λ PHAGE DEVELOPMENT IN ESCHERICHIA COLI SPHEROPLASTS

Abstract

Effect of alteration of cell envelope on the inducibility of λ phage development was studied using various bacterial preparations of the lysogens. Plasmolysis or osmotic shock did not particularly affect spontaneous induction as well as UV inducibility of λ. The λ phage inducibility was, however, significantly reduced by conversion of the lysogens into spheroplasts with lysozyme, glycine, or penicillin. Spontaneous and artificial inductions (by UV or MC) were both affected in these spheroplasts. Thermal induction of λcIts was also reduced considerably, suggesting that somesteps following repressor inactivation were impaired in spheroplasts. On the other hand, spheroplasts of λ lysogens retained the ability to exclude T4rII, even after UV irradiation. Cross induction was not detected in mixed culture of intact F- lysogenic cells and nonlysogenic Hfr spheroplasts. Based on these results, possible relationship between integrity of cell envelope and inducibility of λ phage development was discussed.