38. BIOSYNTHESIS OF PROTEINS IN BACTERIAL CELLS 451 



soluble protein. Radioactivity can also be displaced from ribosomes to 

 soluble protein by incubating cells labeled for a very short time in the 

 absence of the tracer. 



A very elegant demonstration of the early formation of protein in the 

 microsomal particles and of the RNA in the nucleus has been given by 

 Zalockar 212 in radioautographing cells of Neurospora, after incorporation of 

 tritiated precursors of these macromolecules. Similar results have also been 

 obtained by Sirlin 213 in studying the sites of protein and nucleic acid syn- 

 thesis in salivary glands of Surittia. 



212 M. Zalokar, Exptl: Cell Research 19, 114 (1960). 



213 J. L. Sirlin, Exptl. Cell Research, 19, 177 (1960). 



