Demonstration of stage-specific nucleolytic activity in cell-free extracts of Phycomyces and inhibition of this activity by EDTA and G-actin

Abstract

Stage-specific nucleolytic activity was identified in cell-free extracts (CFEs) of Phycomyces. Such activity was not detected in spore germlings or mycelia for the first 36 h after the start of cultivation. However, it was detected in mycelia more than 48 h after the start of cultivation, as well as sporangiophores and sporangia. The nucleolytic activity was completely inhibited by the addition of EDTA or G-actin to the CFE, and the various results together suggest that the activity was due to deoxyribonuclease I (DNase I).