Evidence for the involvement of serine protease in the conidial discharge of Conidiobolus coronatus

The involvement of serine protease(s) in the conidial discharge of Conidiobolus coronatus was investigated using the parent strain and a variant strain with reduced conidial discharge. Time course profiles of protease levels and conidial discharge showed that maximum protease levels coincided with maximum conidial discharge in both the parent and variant strains. Inhibition of serine protease(s) by phenyl methyl sulfonyl fluoride showed that low protease levels resulted in inhibition of the conidial discharge and a minimum activity of 1.0 U/mg protein is essential for triggering the conidial discharge. Using casein to induce proteases, it was further observed that early gain in the protease level (1.0 U/mg protein) leads to early onset of conidial discharge. The above evidence suggests the involvement of protease(s) in the conidial discharge of C. coronatus.