ROBERT E. EAKIN 411 



preparations the relatixe activity of enzymatic inhibition of a 

 series of homologs strikingly paralleled their specific activity in 

 arresting regeneration. On the basis of these results, we proposed 

 that the primary action which eventually results in the inhibition 

 of normal morphogenesis is the inhibition of this specific enzyme. 



CONCLUSION 



By the use of different strains subjected to various physical and 

 chemical treatments one can produce a \ ariety of different regen- 

 eration patterns that can be recognized by macroscopic observa- 

 tions. Treated and untreated organisms exhibiting these different 

 responses can then be used for making comparative histological 

 studies to determine the structural differences in the processes 

 taking place in the different patterns of normal and altered regen- 

 eration. In these same organisms cytochemical, enzymatic, and 

 related types of biochemical studies can likewise be used for com- 

 parative studies. The use of a particular agent, lipoic acid, is a 

 beginning in this approach to establish correlation between the 

 effect of an agent on gross development, its effect upon cellular 

 patterns, and its effect upon specific biochemical reactions. 



REFERENCES 



1. Ham, R. G. 1957. Biochemical studies on regeneration of Inclra. Doctoral Dis- 



sertation, The University of Texas. 



2. Ham, R. G., and R. E.. Eakin. 1958. Time sequence of certain physiological 



events during regeneration in hydra. /. Exp. Zool. 139: 33-54. 



3. Ham, R. G., and R. E. Eakln. 1958. Loss of regenerative capacity in hydra 



treated with lipoic acid. /. Exp. Zool. 139: 55-68. 



4. Ham, R. G., D. C. Fitzgerald, Jr., and R. E. Eakin. 1956. Effects of lithium 



ion on regeneration of hydra in a chemicalh- defined environment. /. Exp. 

 Zool. 133: 559-572. 



5. Henderson, R. F., and R. E. Eakin. 1959. Alteration of regeneration in 



planaria treated with hpoic acid. /. Exp. Zool. 141: 175-190. 



6. Henderson, R. F., and R. E. Eakin. 1960. Inhibition of malic dehydrogenase 



by cyclic disulfides. Biochem. and Biophys. Res. Comin. 3: 169-172. 



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sporidia. /. Protozoology 8: 151-152. 



8. Spangenberg, D. B., and R. G. Ham. 1960. The epidermal nen'c net of hydra. 



;. Exp. Zool. 143: 195-202. 



