The incorporation of microinjected 14C-amino acids into TCA insoluble fractions of the giant axon of the squid

Giant squid axons were microinjected with serine, valine and leucine-C¹⁴ under controlled electrophysiological conditions. These amino acids are incorporated into TCA insoluble fraction in the isolated axon. This incorporation is higher in the stimulated axons as compared to non-stimulated ones. By processing separately the axoplasm and axon sheath, it was found that the last one is responsible almost entirely for the observed incorporation. Through differential centrifugation of homogenates of microinjected axons was shown that the highest incorporation occurred in the 1500 × g sediment, which probably corresponds to membranes. The incorporation of amino acids in stimulated axons, is strongly inhibited by chloramphenicol and actinomycin D.     

The effects of kinetin and contaminating bacteria on the incorporation of 32P-orthophosphate into various fractions of nucleic acid extracted from radish leaves

Summary By comparing ³²P-orthophosphate incorporation into nucleic acid extracts of sterile and non-sterile radish leaf discs, it was shown that contaminating bacteria cause a 2–4 fold increase in the rate of precursor incorporation and alter the pattern of label distribution after fractionation of the extracts by sedimentation through sucrose gradients or chromatography on MAK¹ columns. Using sterile senescing radish leaf discs, a stimulation of ³²P-orthophosphate incorporation into various fractions of nucleic acid was observed as a result of kinetin treatment.