[Comparative electron microscopic study of cultures of Nocardia asteroides and of the Nocardia-like variant, Actinomyces chrysomallus].

The ultrastructural organization of the red-orange cultures of Nocardia (Proactinomyces) asteroides was compared with that of a Nocardia-like variant of Actinomyces (Streptomyces) chrysomallus isolated upon the inoculation of the submerged parent culture. The comparison has demonstrated for the first time that the major difference consists in the structure of their cross partitions. In Nocardia, the septa is split at all stages of its formation; in the Nocardia-like variant, the partitions have the same structure as the cultures of the genus Actinomyces (Streptomyces). Therefore, the accepted terminology is conventional.