Interactions between exogenous deoxyribonucleic acid and membrane vesicles isolated from competent and noncompetent...

Competent cultures of Bacillus subtilis 168 have been fractionated into a high-competent and a low-competent fraction by a large-scale separation technique. Membrane vesicles isolated from both cell fractions are equally active in the transport of L-glutamate. Both membrane vesicle preparations seem to have similar endo- and exonuclease activities. Also, both preparations are capable of binding deoxyribonucleic acid. However, especially at low deoxyribonucleic acid concentrations (1 mug or less per ml), vesicles obtained from competent cells bind significantly more deoxyribonucleic acid (up to sixfold) than vesicles from noncompetent cells.