Employing Aspergillus niger strain 1617, we have made a kinetic analysis of the region of protease formation in the hypha.
When the fungal hyphae, grown by shaking in the ordinary synthetic medium containing sulfate (+S medium), were transferred to the same medium devoid of sulfate (-S medium), they produced acid protease after an induction period of 5hr. Making use of this phenomenon, the fungal conidia were grown in several batches of +S media (primary culture) each for different period and the growing hyphae transferred to -S media (secondary culture). Then the course of protease formation was followed in each culture.
From the kinetic analysis of the data of the above experiments, it was concluded that the apical growing region of ca. 40μ does not respond to the S-deficiency which causes protease induction, and the portion, following this, of ca. 30μ responds to the S-deficiency. The inducible region is followed by a region of protease formation. The site of septum formation in relation to these regions is discussed.