Abstract
Nucleic acid biosynthesis of Angiostrongylus costaricensis was examined with various inhibitors; aminopterin (inhibitor of purine and pyrimidine de novo biosynthetic pathways), 8-azaguanine (specific inhibitor of purine salvage pathway) and PALA (specific inhibitor of pyrimidine de novo biosynthetic pathway) were applied in in vitro culture developing from the third stage larvae to young adult in chemically defined medium. It was suggested that A. costaricensis possessed functional purine and pyrimidine de novo biosynthetic pathways and also that they could utilize exogenous sources of purines and pyrimidines by salvage pathways for their development.