Observation of the nuclear behavior in Streptomyces cinnamonensis

The nuclear region in the hyphae of Streptomyces cinnamonensis consists of two phases: a dense fibrillar phase and a less dense phase in which the fibrillar phase is embedded. The fibrillar phase occurs in two states of aggregation, a dispersed condition in which a network of fine fibrils is apparent and a more organized condition in which the fibrils appear thicker and more compact and exhibit a variety of configurations. The fibrils may be dispersed throughout the nuclear region, either in a whorled pattern or in a more or less straightened manner aligned along the nuclear axis. They may aggregate toward the center of the nuclear region as a dense mass which may be separated into two daughter groups of fibrils. Often the nuclear region between the two daughter groups of fibrils is subdivided by cytoplasmic invagination. Conversely, the two daughter groups of fibrils divide a second time resulting in four masses of fibrils. Thus several nuclear regions may be located in a common cytoplasmic field. The significance of these findings is discussed.