High energy phosphate metabolites observed by NMR in infective larvae of Haemonchus contortus.

Phosphorus resonances consistent with phosphoarginine and ATP were observed in the in vivo 31 P-nuclear magnetic resonance (NMR) spectra of infective larvae of Haemonchus contortus. The level of phosphoarginine quickly declined when nematode suspensions were purged with nitrogen and was restored upon return to aerobic conditions. Saturation transfer NMR demonstrated forward and reverse exchange of phosphorus between phosphoarginine and ATP.