Qualitative assays of ribonuclease produced by plant pathogenic fungi

Abstract

The extracellular production of ribonuclease by fungi grown on solid and liquid media was demonstrated by turbidity of remaining RNA, ultraviolet absorption by hydrolytic products, spectral shift of thionine, and fluorescence of acridine orange. The test fungi varied considerably in their ability to produce ribonuclease, but slight activity was detected with all eight fungi tested in liquid media. The results of liquid assays were not in complete agreement, probably because the four tests measured different features of the hydrolysis of RNA. Assays of 15 fungi on solid media were useful only in the qualitative detection of ribonuclease.