SlOO fractions were isolated from submerged cultures of well conidiating (No. 45H), nonconidiating (No. 52-1) and factor C treated No. 52-1 Streptomyces griseus strains and analyzed by one-dimensional SDS-PAGE. The quantity and synthesis of soluble proteins were examined on densitograms and fluorograms. The evaluation was carried out by a computer aided method. Specific radioactivities of the protein bands were also calculated.Some groups of protein bands were found to be characteristic of the two strains during development. On the other hand densitograms of the two strains could be in part superimposed showing similarities in the position and relative intensity of bands.Most of the soluble proteins were synthesized all over the life-cycle of both strains, although characteristic individual bands appeared or disappeared during differentiation or when the two strains were compared.The protein pattern of SlOO fraction from factor C treated No. 52-1 cultures became similar although not identical, with that of strain No. 45H. Fluorograms showed closer similarities than densitograms. At 40 h. there were certain peaks of specific radioactivity in the factor C treated mycelium which were missing from strain No. 45H of that age, but were expressed later in the 64 h old mycelium.Although the bands obtained by one-dimensional SDS-PAGE did not represent individual proteins, the results shown demonstrate that our method is suitable for the characterization of the process of biochemical differentiation. The quantitative changes of some bands detected by densiometry, fluorography and specific radioactivity may reflect important events of differentiation (Table 1).
1969).27 J. Basic Microbiol. 28 (lQ88) 6