THE ROLE OF SOME ENZYMES IN THE 

 DEVELOPMENT OF ASCIDIANS 



G. REVERBERI: zoological institute, 



UNIVERSITY, PALERMO, ITALY 



The cytologists of the past century, closing their research and 

 their discussion on mitochondria, could not suspect that a new 

 brilliant mitochondrial era would be opened in the next century 

 by the work of the biochemists. In any scientific movement it is 

 always difficult to fix exactly the starting point; but perhaps we 

 are not much mistaken in ascribing the beginning of the new 

 golden age of mitochondria to the fundamental discovery of 

 Green et al. ( 1948 ) , by which it was established that the com- 

 plete oxidation of pyruvate and the connected oxidative phos- 

 phorylation are carried out by a group of enzymes and coenzymes 

 that are situated in the particulate elements of the cytoplasm. In 

 the years that followed other important discoveries were made, 

 particularly in the past five years, and enzymology became in a 

 short time one of the most prosperous branches of biology. 



Morphologists, physiologists, and even the embryologists could 

 not remain indifferent to these new discoveries; they immediately 

 felt that a reconsideration of some of the old, dismissed problems 

 would be very profitable. 



The morphologists were much helped in such reconsideration 

 by the electron microscope which disclosed, in the mitochondria, 

 unsuspected features. In fact, the electron microscope revealed 

 a mitochondrial structure with transversal bands or "cristae mito- 

 chondriales," as they were named. The problem arose as to their 

 meaning, and of course that problem led to many other problems. 



The physiologists, for their part, were particularly affected by 

 the new discoveries, as they shed new light on the problems of 



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