Quantitive autoradiographic study of competence and deoxyribonucleic acid incorporation in Bacillus subtilis.
The relationships among deoxyribonucleic acid (DNA) uptake, transformation, and autoradiographic labeling were investigated. It is shown that: (i) autoradiography is a good method for measuring the total fraction of competent cells able to incorporate transforming DNA; in our best experiment that fraction was 11.5%. (ii) Computation of the fraction of competent cells in a culture of Bacillus subtilis, by comparing the frequencies of single and double transformants for two unlinked markers, gives values which are somewhat different from those obtained by auto-radiography. (iii) On the average, a competent cell of B. subtilis irreversibly takes up from 0.9 x 10(-10) to 1.4 x 10(-10) mug of DNA; this amount represents about 1/55 to 1/35 of the bacterial chromosome weighing 5 x 10(-9) mug, and corresponds to three to six DNA molecules having a molecular weight of 1.6 x 10(7).
D001345:Autoradiography; D001412:Bacillus subtilis / Q000378:metabolism*; D002876:Chromosomes, Bacterial; D004269:DNA, Bacterial / Q000378:metabolism*; D008970:Molecular Weight; D014170:Transformation, Genetic
D004269:DNA, Bacterial