In a variation of the experiment in the previous question,

In a variation of the experiment in the previous question, the following materials were added to three separate cell-free systems, generating the indicated results:
Materials Added Results
Radioactive amino acids Radioactive protein produced
Radioactive amino acids Radioactive protein produced and DNase (a DNA-digesting enzyme)
Several hours after grinding:
Radioactive amino acids No radioactive protein produced and DNase
What is the best interpretation of these observations?