The Significance of the Large Bodies and the Development of L Type of Colonies in Bacterial Cultures

Abstract

The occurrence of deeply stained large round bodies in bacterial cultures has long been known. These large bodies have aroused much speculation, but from the study of the literature nothing definite can be learned concerning their nature and functions, and the majority of bacteriologists regard them as products of degeneration. The author has previously pointed out (1939a) that the large bodies which give the characteristic appearance to the cultures of L1 and of the pleuropneumonia group of organisms are morphologically very similar to the large bodies of bacteria and are probably analogous in nature. If this supposition is correct, we must obtain more information concerning the nature of the large bodies in order to understand the nature of L1 and of the pleuropneumonia group of organisms and their relationship to other microorganisms. The large bodies in most cultures degenerate without further development. It is not unreasonable to expect that in some cultures their functions will be apparent if we study a large number of cultures belonging to different species. With this thought in mind, many routine bacteriological cultures have been examined during the last three years for the occurrence of large bodies. When they were found, their properties and their eventual development was studied both in the original cultures and in transplants. Between 3,000 and 6,000 cultures were examined although their exact number is not known since no records were kept of the cultures which showed no, or only a few, large bodies. By this procedure strains which produced large bodies in abundance were found in many bacterial species. They occurred only occasionally among freshly isolated strains of Escherichia coli, Hemophilus influenzae and Hemophilus parainfluenzae, gram-positive aerobic sporebearing bacilli and Streptococcus. Colonies in which nearly all cocci transformed into large bodies were frequently seen in gonococcus cultures grown directly from patients, and all strains of 1 The expenses of this investigation have been defrayed in part by a grant from the Commonwealth Fund. This is publication 57 of the Robert W. Lovett Memorial.

Pleomorphism in Hemophilus Hemolyticus Caused by V‐factor Deficiency

“…We have repeatedly found strains of E. coli in cases of chronic urinary infection, which showed a similar pleomorphism. Dienes has already drawn attention to this fact (5).…”

Rapid Detection and Isolation of Mycoplasmas From Cell Cultures

“…Negative plates were further incubated for periods of up to 2 weeks. At this time those plates remaining negative were examined after the addition of Dienes stain (Dienes, 1942).…”

Micro‐organisms of the Pleuropneumonia Group

“…It may be sufficient for identification to find the characteristic colonies, but it is often desirable to stain the colonies as a whole for high-power microscopy. Dienes (1939Dienes ( , 1942Dienes ( , 1945 spreads an alcoholic solution of methylene blue and azure on the surface of a cover-slip. After the evaporation of the alcohol the slip is covered with a loopful of 0.5 yo phosphoric acid, and when the water has disappeared, a bright blue film remains.…”