STUDIES ON THE FRAGMENTATION OF NOCARDIA ERYTHROPOLIS IN LIQUID MEDIUM

Abstract

Growth studies of Nocardia erythropolis, an actinomycete described previously on cytological bases as reproducing by fragmentation, were carried out with cultures in liquid medium. Multiplication of this organism, indicated by viable counts, total cell counts expressed as particle production, and cell mass increase measured by optical density or cell volume increases, was significantly different from eubacterial multiplication. Two distinct phases were noted during the growth cycle. Active growth of the organism, as measured by cell mass, occurred early in the cycle in the absence of an increased viable count. Conversely, in the later phase of fragmentation, numbers of viable particles increased without a concomitant increase in cell mass. Toward the end of the phase of fragmentation the viability of the fragmentation product decreased markedly. It is postulated that nonviable fragments are in part a result of septum deposition which separates cytoplasmic elements of coenocytic filaments not containing nuclear elements.