Ribonucleic acid and morphogenesis in the fungus, Mucor rouxii

The fungus, Mucor rouxii, can grow in two morphological states depending on culture conditions. The present work analyzed total RNA populations from aerobically grown filamentous cells and anaerobically grown (in an atmosphere of N2) yeast-like cells of this organism. No differences in the RNA populations were revealed by competition hybridization, using the filter technique in a formamide - standard saline citrate system. Limitations of the hybridization technique and RNA isolation methods were discussed as possible reasons for this result. DNA optical renaturation experiments gave a genome size of 7.2 x 1^9 daltons for M. rouxii, with no evidence of significant DNA redundancy. These results were confirmed on hydroxyapatite. The difficulties of obtaining highly labeled, stable 3H-DNA prevented the completion of in-solution hybridizations to determine the extent of genomic transcription. Preparing DNA labeled at very high specific activity with a radioisotope other than tritium might hold promise in answering this question