CULTURE OF CELLS AND TISSUES DERIVED FROM XENOPUS LAEVIS 621 



to a powerful antifungal agent, amphotericin B or Fungizone (SQUIBB), at a 

 concentration of 3 yig per ml 1 . 



Table I 



Composition of média for aseptic rearing of embryos and young tadpoles 

 of Xenopus laevis 



Rearing Media (1000 ml) 



ABIOT-RS-A1 



ABIOT-RS-A2 ABIOT-RS-A3 



Z "<5 



a h 



-!2h 



NaCl 



KC1 



Ca(N0 3 ) 2 .4H 2 6 ! ! 

 MgS0 4 .7H 2 . . . 

 Na 2 HP0 4 .12H 2 . 



KH 2 P0 4 



NaHC0 3 



H 2 



Penicillin G ... 

 Streptomycin sulfate 

 Tetracycline-HCl . 

 Sulfathiazole . . . 

 Fungizone-Squibb 

 (Amphotericin B) . 



340 mg 

 5 mg 

 8 mg 

 21 mg 

 28 mg 

 2 mg 

 20 mg 

 1000 ml 

 300,000 units 

 300 mg 

 10 mg 

 







340 mg 

 5 mg 

 8 mg 

 21 mg 

 28 mg 

 2 mg 

 20 mg 

 1000 ml 

 300,000 units 

 300 mg 

 10 mg 

 500 mg 







340 mg 

 5 mg 

 8 mg 

 21 mg 

 28 mg 



2 mg 

 20 mg 



1000 ml 

 units 

 mg 

 mg 

 mg 



3 mg 



Add 2 ml of IN/NaOH to each solution before sterilization. 



Sterilized by filtration through Millipore filter, type GS, 0.22 \x pore size, under position pressure; 

 Ail média stored frozen at — 25° C and protected from exposure to light, until used. 



B. De contamination of normally reared tadpoles and of frogs 



Prior to the explantation procédures normally reared tadpoles are starved 

 for several days, then transfered to our rearing-medium ABIOT-RS-A2 and 

 kept there for 48 hours with daily transfers into fresh médium at room température. 



Frogs, selected for the préparation of cultures from internai organs (kidney, 

 spleen etc.) are bathed for a few minutes in dilute solutions of Haemo-Sol 

 (MERZ and DADE), anestesized in 1 :2000 solution of M. S. 222 (SANDOZ), 

 then washed quickly in 1% solutions of Lysol or Desogen (GEIGY), and sub- 

 I sequently brushed over superficially with 70% ethanol. 



1 Fungizone is highly toxic to embryos and larvae of Xenopus laevis. In embryos it causes 

 extensive damage to the developing axial structures and ultimately death of the hatching embryos. 

 Fully developed tadpoles, on the other hand, do not survive continuous exposure to Fungizone 

 at concentrations which effectively suppress fungal contaminations (3 \xg per ml). Therefore, 

 Fungizone cannot be incorporated into média for the rearing of embryos and young tadpoles, 

 and exposure of fully developed tadpoles to this antibiotic must be limited to a few hours. 



