Effects of protein inhibitors and auxin on nucleic Acid metabolism in peanut cotyledons

Abstract

The accumulation of labeled phosphorus into newly synthesized nucleic acids or peanut cotyledon slices incubated with chloramphenicol, puromycin, or 2,4-dichlorophenoxyacetic acid (2,4-D) was reduced. Promotion of nucleic acid synthesis was not noted by any of these chemicals. Chloramphenicol completely inhibited the synthesis of the DNA-RNA fraction at 1.25 x 10(-3)m while soluble and ribosomal RNA was inhibited by 70% and 80%, respectively. At the same concentration messenger RNA was inhibited by only 40%. These effects suggest that chloramphenicol inhibit nucleic acid synthesis in peanut cotyledons in a differential manner. Similar results were noted for DNA at low concentrations of 2,4-D. However, at high concentrations of 2,4-D, DNA as well as RNA fractions were inhibited in a similar manner at a given concentration. Puromycin did not differentially inhibit nucleic acid synthesis except at 2 x 10(-3)m where DNA was least inhibited.Nondifferential inhibition suggests that a common site or precursor pool essential for the synthesis of all nucleic acid fractions is altered. Differential inhibition may be due to the interference with a specific rate-limiting step, directly or indirectly, in the formation of a particular nucleic acid.