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THE BIOLOGY OF HYDRA : 1961 



10 

 SB 



20 30 

 MB 



40 50 60 

 ST 



HOURS AFTER FEEDING 



70 



LT 



Fig. 3. DNA, RNA, and protein content of Hydra in different stages of 

 budding. The symbols SB, MB, ST, and LT represent the small bud, medium 

 bud, short tentacled, and long tentacled stage animals. 



These data reveal the first major chemical difference between par- 

 ent and bud tissues, the DNA/ protein ratio of the bud being three 

 times that of the parent Hydra. 



Since the experiments in Figure 3 gave no indication of the bud 

 possessing this high DNA/protein ratio, another type of experiment 

 was carried out to determine whether this high ratio was already 

 present in an early stage of bud tissue. In these experiments (Fig. 

 5 ) , we excised only the bud portion of a "medium bud" stage Hydra 

 and then determined the respective chemical composition of the 

 dissected parents and buds. It can be seen that, although there is 

 much less protein in the dissected bud than in the remaining parent, 

 the DNA contents of both parts are nearly equal. More striking is 

 the high DNA/protein ratio of the dissected bud. These results 



