ARTICLE

CYTOPLASMIC DNA SYNTHESIS IN AMOEBA PROTEUS : I. On the Particulate Nature of the DNA-Containing Elements

M. Rabinovitch M.D.¹ and W. Plaut Ph.D.¹

¹ From the Department of Zoology, University of Wisconsin, Madison, Wisconsin.

Dr. Rabinovitch's permanent address is Faculty of Medicine, University of São Paulo, São Paulo, Brazil

The incorporation of tritiated thymidine in Amoeba proteus was reinvestigated in order to see if it could be associated with microscopically detectable structures. Staining experiments with basic dyes, including the fluorochrome acridine orange, revealed the presence of large numbers of 0.3 to 0.5 µ particles in the cytoplasm of all cells studied. The effect of nuclease digestion on the dye affinity of the particles suggests that they contain DNA as well as RNA. Centrifugation of living cells at 10,000 g leads to the sedimentation of the particles in the centrifugal third of the ameba near the nucleus. Analysis of centrifuged cells which had been incubated with H₃-thymidine showed a very high degree of correlation between the location of the nucleic acid-containing granules and that of acid-insoluble, deoxyribonuclease-sensitive labeled molecules and leads to the conclusion that cytoplasmic DNA synthesis in Amoeba proteus occurs in association with these particles.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Jeon, K. W. (1972). Development of Cellular Dependence on Infective Organisms: Micrurgical Studies in Amoebas. Science 176: 1122-1123 [Abstract]  
• Guttes, E., Guttes, S. (1964). Thymidine Incorporation by Mitochondria in Physarum polycephalum. Science 145: 1057-1058 [Abstract]  

Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents