ISOLATION AND CHARACTERIZATION OF SOLUBLE RNA FROM DORMANT AND GERMINATED CONIDIA OF ASPERGILLUS ORYZAE

Abstract

Extraction and purification of soluble RNA (sRNA) from dormant and germinated conidia of Aspergillus oryzae were carried out. The direct extraction with water-saturated phenol of sRNA from intact cells, successfully employed in various organisms, was found employable only on germinated conidia but not on dormant ones. Therefore, in the present investigation sRNA from dormant and germinated conidia were extracted with sodium dodecylsulfate-phenol from the supernatant fraction of disrupted cells. The purification method finally adopted was the deoxyribonuclease digestion followed by the DEAF-cellulose column chromatography.
Both the sRNA samples thus obtained from dormant and germinated conidia gave the sedimentation coefficient of 4S with a single and symmetric pattern. The nucleotide analysis of either sample also showed the composition characteristic to sRNA. The thermal denaturation profile was rather broad in comparison with yeast sRNA and T_m-value of 65° was obtained in 5mM MgCl₂ (pH 7.6). Since the amino acid-acceptor activities of both samples were low, no final conclusion could be deduced wheather or not there were any difference in these activities between the two sRNA samples.