The diguanosine nucleotides: do they exist in aquatic fungi?

The aquatic fungi Achlya ambisexualis and Blastocladiella emersonii were grown in the presence of 32Pi and the 32P-labeled acid-soluble nucleotide fractions were analyzed by ion-exchange chromatography on DEAE-cellulose. Selected column fractions containing diguanosine tri- and tetra-phosphates (Gp3G and Gp4G) added as chromatographic markers were analyzed further for 32P by chromatography and (or) enzyme hydrolysis. The results of these experiments clearly indicate that neither Gp4G nor Gp3G is synthesized during vegetative growth of these organisms and cast doubt on the hypothesis that diguanosine nucleotides are important metabolic regulators in fungi.