[Synchronous growth in liquid medium of species related to "Mycobacterium rhodochrous": "Nocardia restricta" and "Jensenia canicruria" (author's transl)].

The synchronous development of nocardioform and coryneform populations had not yet been studied. We have observed that it is possible to obtain a synchronous growth of Nocardia restricta and Jensenia canicruria (species related to Mycobacterium rhodochrous) in a liquid synthetic medium by inoculating the medium with spherical cells taken during the advanced stationary phase, at the end of the cell division cycle. Good synchrony produces a series of breaks in the slope of culture absorbance and of cell protein content. DNA replication checked either by cell DNA content measurements or by pulse-incorporations of tritiated thymidine, is discontinous; peaks of incorporation of thymidine follow one another with a periodicity equal to the generation time. A study of the cell division cycle, hitherto unknown, is now possible.