Location of branches within the apical hyphal region of Streptomyces granaticolor mycelia.

Abstract

The location of branches (ramifications) within the apical hyphal region of Streptomyces granaticolor mycelia was studied in dependence on the specific growth rate by using batch and chemostat cultures. The site where a new branch emerged was correlated to the neighboured elongation sites (e-sites) as well as to the septae. In dependence on the growth rate the distance from a newly formed branch (i.e. e-site) to the apical e-site (tip of the main hypha) changed from 12 to 44 microns and to the e-site on the tip of the preceding neighboured branch from 12 to 27 microns. Thus, except for the slowest grown culture, the new branching site in the apical hyphal region did not represent the midst between the two preexisting e-sites. Comparing branching and septation sites, the data indicated a close correlation between them, if the respective mean values of whole populations were determined. But regarding individual hyphae, only 4-39%--depending on the growth rate--of the apical branches were directly neighboured to a septum. The remaining percentage was situated at one of several potential branching sites, the number of which per subapical cell corresponded to the number of nucleoids.