Goldsmith M R, Havas S W, Ma R I, Kallenbach N R
J Bacteriol. 1970 Jun;102(3):774-83. doi: 10.1128/jb.102.3.774-783.1970.
The intercellular transfer of competence during growth under the conditions specified by the transformation procedure of Spizizen was investigated with Bacillus subtilis 168. The rate of competence development as assayed uniformly in medium B was not affected by variations in the cell concentration, although the first appearance of transformants occurred earlier with high cell densities in medium A, approximately in proportion to the onset of the stationary phase in the culture. Growth in the presence of Pronase enhanced the frequency of transformation, but did not detectably alter the kinetics of competence development. The rate of competence increase in physiologically noncompetent cultures was not changed by mixing with competent cultures either in medium A or in medium B; however, an early appearance of transformants was noted in mixed cultures in which the proportion of competent to noncompetent cells prevented exponential growth of the noncompetent strain. These experiments indicate that the normal development of competence in B. subtilis is not mediated by a soluble or loosely bound protein factor capable of transmitting competence directly via cell contact. The onset of competence is thus a function of internal physiological changes which are induced by the overall metabolic state of the culture.
采用枯草芽孢杆菌168研究了在斯皮齐曾转化程序所规定的条件下生长期间感受态的细胞间转移。在培养基B中统一测定的感受态发展速率不受细胞浓度变化的影响，尽管在培养基A中细胞密度高时转化子首次出现的时间较早，大约与培养物中稳定期的开始成比例。在链霉蛋白酶存在下生长提高了转化频率，但未显著改变感受态发展的动力学。生理上无感受态的培养物中感受态增加的速率，在培养基A或培养基B中与有感受态的培养物混合后均未改变；然而，在有感受态细胞与无感受态细胞的比例阻止无感受态菌株指数生长的混合培养物中，观察到转化子提前出现。这些实验表明，枯草芽孢杆菌中感受态的正常发展不是由能够通过细胞接触直接传递感受态的可溶性或松散结合的蛋白质因子介导的。因此，感受态的开始是由培养物的整体代谢状态诱导的内部生理变化的函数。
