CULTURE OF CELLS AND TISSUES DERIVED F ROM XENOPUS LAI N IS 



627 



Observations with cultures derived from xenopus lai vis whole embryos 



and whole tadpoles 



Practically without exception luxuriously growing cultures are obtained 

 when cells and small tissue fragments isolated from advanced Xenopus embryos 

 (stages 35 to 40) and from young swimming Xenopus tadpoles (stages 42 to 45) 



F ' 



Fig, 2 c 



c) early-anaphase chromosomes (magni- 

 fication, 7750 X). Hypotonie treatment 

 directly on culture slides (10 minutes at 

 room température in 20 % WS-AO + 80 % 

 H 2 0); fixed (Acetic acid — methanol 

 mixture 1 :3), air dried and stained 

 (Orceïn). 



Fig. 3 



Primary-explant cultures derived from 

 whole advanced embryos and whole 

 young tadpoles of Xenopus laevis, grown 

 in TCM-A2 at room température: Petri- 

 dish culture 2 weeks old, flask culture 

 3 weeks old. Fixed (Bouin) and stained 

 (Hematoxylin-eosin). 



are explanted with growth médium TCM-A2 (see Figure 3). Fetal bovine sérum 

 at a concentration of 20% (by volume) in the primary-explant médium causes 

 rapid and tight attachment to the surface of the culture vessels not only of iso- 

 lated cells and small cell clumps but also of relatively large fragments of organs 

 such as tail (see Figure 4a) or intestinal tract (see Figure 4b). In thèse cultures 

 cells begin to multiply almost immediately after attachment, that is usually 



