| Abstract: | The objective of this study was to partially characterize and follow the temporal expression of the enzyme ornithine decarboxylase (ODC) throughout embryonic and early larval development of Musca domestica. Enzymatically active ODC was shown to be present at detectable levels in the embryos only during the latter stages of embryogenesis. This temporally expressed enzyme displayed maximum activity at the time of hatching, and the activity rapidly declined in the newly hatched larvae. The half-life of ODC activity in extracts at the time of hatching and 30 min after hatching was 57 min and 12 min, respectively. The subunit molecular weight of the embryonic ODC was determined to be 46,000, and the apparent native molecular weight was determined to be 276,000. The concentrations of the polyamines putrescine, spermidine, and spermine also were determined throughout embryogenesis. Spermidine was found to be present in the embryos at about 10-fold higher concentrations than spermine and at about 100-fold higher concentrations than putrescine. These polyamines did not undergo major changes in concentration throughout development of the embryos. |
