Christie, Caroline Anne2014-12-172014-12-172014-12-17http://hdl.handle.net/10539/16010A Dissertation Submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg for the Degree of Master of Science March 1982The effects of '5-FUdR and 5-BUdR on differentiation and metamorphosis in Xenopus lacyis tadpoles were studied. In particular, a detailed study was made of the effects of 5-fUdR on cellular patterning and tissue differentiation during hind’imb development. Xenopus ,laevis tadpoles grown in solutions of 5-FUdR and 5-BUdR demonstrated hindlimb deformities* which were analysed by staining for cartilage visibility. Furthermore a comparison of the uptake of exogenous radioactive thymidine in the presence and absence of 5-FUdR by ^ejropus 1aevis tadpoles showed that 5-FUdR depressed exogenous thymidine uptahe, A buoyant density gradient analysis of G-BUdR-substituted DHA was undertaken using the analytical ultraccntrifuge. The resulting ultraviolet absorption photographs showed bands heavy and noria&l DMA, A aodel is proposed to explain the patterning of the Xenopus 1aevis hindlinb in the presence or absence of 5-FUdR.enThesis