Stimulation of Bacillus subtilis transformation by spermidine.

Addition of spermidine in millimolar concentrations to Bacillus subtilis cells curing competence development increases transformability. The spermidine must be added at least 30 min before DNA for maximum stimulation. An incubation period of about 30 minutes is also required for the maximum uptake of labeled spermidine. The amount of DNA initially attached and the rate of DNA uptake are increased to the same extent as transformation. The rate of protein synthesis is also equivalently increased. These observations are consistent with an increase in the number of competent cells in the cell population; this increase is mediated by a spermidine-stimulated protein synthesis.