INCORPORATION OF RADIOACTIVE AMINO ACIDS AND BASES INTO NUCLEIC ACID AND PROTEIN FRACTIONS OF GERMINATING SPORES OF BACILLUS SUBTILIS

Abstract

Using germinating spores of Bacillus subtilis Marburg, synthesis of macromolecules was studied by assay of radioactive amino acids and bases incorporated into protein and nucleic acid fractions. In spores heated at 70° for 10min, incorporation into protein and RNA fractions occurred simultaneously, but incorporation into DNA fraction about 40-50min later. But, when the spores were heated at 90° for 5min, "germination delay" was observed. In the spores, incorporation into RNA fraction occurred earlier than incorporation into protein. Early incorporation into protein was inhibited by actinomycin S, and later incorporation into RNA fraction was inhibited by chloramphenicol, puromycin and p-fluorophenylalanine. These agents also inhibited the incorporation into DNA fraction. On these grounds, the possibility was discussed that synthesis during germination occurred in a sequence of RNA, protein, and DNA, and the RNA synthesized in the early period of germination was essential for the following synthesis of protein, which might, in turn, play an important role in the subsequent synthesis of RNA and DNA during outgrowth.