FURTHER OBSERVATIONS ON THE CARBON DIOXIDE INCORPORATION INTO RNA IN THE EARLY PHASE OF CONIDIA GERMINATION IN ASPERGILLUS ORYZAE WITH SPECIAL REFERENCE TO SOLUBLE RNA SYNTHESIS

Abstract

Using Aspergillus oryzae conidia. timing of the syntheses of various RNA classes in the early phase of germination was investigated. The methylated albumin-coated kieselguhl column chromatography was employed for the fractionation of RNA classes extracted from the conidia which had been labeled with 14CO2 for different periods of germination. Following the synthesis of ribosomal RNA (rRNA) at the very initial step of germination, the synthesis or the modification of soluble RNA (sRNA) was found to commence not later than 15 min. of cultivation. After the hydrolysis of the 14c-labeled rRNA and sRNA, the hydrolyzates were subjected to paper chromatography and radioactivities of bases (or nucleotides) scanned. The results showed that bases of rRNA were almost evenly labeled, while those of sRNA quite unevenly (higher specific activities in pyrimidine nucleotides than in purine ones).