REGENERATION* 



DEFINITION : The restitution of a lost organ In such a form that It Is both structurally 

 and functionally complete. 



PURPOSE : To determine the ahllity of an emhryo or larva to repair or replace a lost part. 



MATERIALS : 



Biological : Rana: stages #10 to #17 and 5 5 to k.^ cm. tadpoles (may he used up to 

 8 cm. ) . 

 Amblystoma: stages #10 1:0 #29 and larvae with llmhs, before metamorphosis. 

 Triturus: stages #10 to #29 and late larvae. 



Technical : Standard operating equipment. 



Sodium sulfadiazine - 0.5^ aqueous (to prevent post-operative infection). 



METHOD : 



Precautions : 



1. Moderate precautions should be taken against bacterial contamination. Animals 

 may be reared in 0.5^ sodium sulfadiazine as protection. 



2. Keep operated animals in sopara^ce containers. The Urodeles particularly tend to 

 snap at any moving object and will bite off each others tails or appendages. 

 Provide adequate volume of medium and space for each specimen. 



5. After the wound is healed over all animals must be maximally fed (Enchytrea for 

 the Urodela and spinach for the Anura). 



Controls : 



1. Tall-fin controls consist of unoperated embryos of the same age and stage. 



2. Limb regeneration control consists of the limb of the opposite side. 



5. Blastema control consists of the transplantation of some other and neutral area 

 (unknown anlage) Into the blastema. 



Experimental procedure : 



TAIL-FIN REGENERATION 



Using either anuran tadpoles (stage #25 or older) or urodele larvae (stage #14-5 or 

 older) with distinct tail fins, select as many specimens as possible of the same age 

 and at the same stage of development. If anuran tadpoles are used they may be placed 

 in groups of 5 in single finger bowls containing a minimum of 25 cc. of medium. If 

 Urodele larvae are used they must be kept in separate containers such as finger bowls, 

 Lily cups, or #2 Stenders. 



The following directions are for Anuran tadpoxes: 



1. Prepare I8 finger bowls, 6 each with the follovrtng solutions (50 cc. each). 



a. 10^ Standard Solution (hypotonic) 



b. Standard Solution (isotonic) 



c. 200^ Standard Solution (hypertonic) 



2. Into each finger bowl place an equal number of tadpoles, a minimum of 5. 

 5. Mark the 6 finger bowls containing the same medium as follows: 



a. Vertical cut. 



b. Cut angled toward the dorsal body wall. 



c. Cut angled toward the belly. 



d. V-shaped cut, apex toward body. 



e. V-shaped cut, apex away from body 



f. Control - no cut. 



* The author acknowledges, with appreciation, the critical suggestions of Dr. H. S. Emer- 

 son in organizing this exercise, particularly that part relating to inductions within 

 the blastema. 



-512- 



