MORPHOLOGICAL STUDIES IN THE GENUS NOCARDIA II

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Abstract
Studies of stained prepns. of 6-month-old cultures of 46 strains of Nocardia sp. revealed 3 types of development. Strains that were most bacterial in colonial texture produce a preponderance of coccoid cells. Pasty-textured forms develop pleomorphic rods for the most part, and waxy- and cartilaginous-textured forms show "ghost filaments," homogeneously stained hyphae, and filaments with discrete cytoplasmic condensations separated by clear areas. The 46 strains studied were Gram-positive, non-acid fast and had a marked affinity for basic aniline dyes. Cytological studies of Proactinomyces (Nocardia) ruber by means of both light and electron microscopy, revealed that: the cell wall is thin, plastic and flexible, cell division is initiated by a separation of the cytoplasm, without the previous deposition of a demonstrable septum, the cytoplasm is alveolar in structure, large vacuoles develop in filaments as they age, 2 types of granules are present in the cytoplasm which do not possess the solubilities of volutin and do not give a positive Feulgen reaction, fat globules are present and glycogen-like material was demonstrated.
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