Purine metabolism by the avian malarial parasite Plasmodium lophurae.
Extracts of normal duckling erythrocytes catabolized AMP to IMP, inosine and hypoxanthine; adenosine and adenine were not formed from AMP. When erythrocyte-free Plasmodium lophurae, prepared by antibody lysis, were incubated in the presence of [14C]hypoxanthine approximately 60% of the label was recovered as purine nucleotides and there was not evidence of extracellular alteration of added hypoxanthine. However, when adenosine was added to suspensions of antibody- or saponin-prepared parasites extensive conversion to inosine and hypoxanthine occurred. This conversion was found to be the result of parasite lysis with release of cytosolic purine salvage pathway enzymes; plasmodial surface membrane ecto-enzymes were not responsible for adenosine catabolism. It appears that in vivo the intracellular plasmodium utilizes the normal erythrocytic process of purine turnover to avail itself of hypoxanthine, the red cell's end product, and at the same time the parasite avoids direct competition for adenosine essential to erythrocyte survival. Since the blood plasma of infected ducklings contained increased amounts of hypoxanthine it is possible that P. lophurae also utilizes this as a purine source.
D000227:Adenine Nucleotides / Q000378:metabolism; D000818:Animals; D004372:Ducks / Q000469:parasitology*; D004912:Erythrocytes / Q000378:metabolism*; D006790:Host-Parasite Interactions; D007042:Hypoxanthines / Q000378:metabolism; D008289:Malaria, Avian / Q000378:metabolism / Q000469:parasitology; D010961:Plasmodium / Q000378:metabolism*; D011685:Purine Nucleotides / Q000378:metabolism; D011687:Purines / Q000097:blood / Q000378:metabolism*
D000227:Adenine Nucleotides; D007042:Hypoxanthines; D011685:Purine Nucleotides; D011687:Purines