Guanylate requirement for patterning the postcephalic body region of the brine shrimp Artemia.

Mycophenolic acid (MA) reduces growth and survival rates of Artemia larvae fed hypoxanthine. The inhibitory effect of MA is suppressed by dietary guanosine as expected for inosinate dehydrogenase inhibition. Pulse MA treatments lasting 24 h imposed on larvae from 24 to 96 h posthatch result in the production of abnormal adults with thoracic, genital or abdominal defects. The MA-induced anomalies are interpreted as a disruption of pattern formation. Since dietary guanosine restores normal pattern in adults developing from larvae, MA-treated during early stages, it is concluded that guanylate production is required at critical developmental times to establish normal developmental fates.