ATPase activity in cells of the yeast Saccharomycopsis fibuligera during mycelial growth.

Levels of ATPase activity were examined in the cells of Saccharomycopsis fibuligera during mycelial growth. The mycelial cells (M-form cells) grown under standing culture conditions exhibited a marked increase of ATPase activity after 3 days, showing a broad peak between 5 and 20 days and a maximum at 10 days. The dry weight/ml of the yeast-like cells (Y-form cells) grown under shaking culture conditions reached its peak after 3 days and remained constant throughout the 10 day period of observation. The dry weight/ml of the M-form cells under standing culture conditions exhibited its peak in 10-15 days and then gradually decreased. A very small amount of Y-form cells among the M-form cells under standing culture conditions, exhibited very low ATPase activity even in 10 days' incubation. In M-form cells, the particles increased in number during 20 days of incubation.