Incorporation of fatty acids and amino acids by cultured Pneumocystis carinii.

Cultured P. carinii rapidly took up a variety of fatty acids. The relative rates of uptake for four fatty acids were 18:1 >> 16:0 approximately equal to 18:0 approximately equal to 18:2. Fatty acids were primarily incorporated into phospholipids and the uptake process was specifically inhibited by 2.2 and 22 microM primaquine, a concentration having no effect on host cells. Amino acids were also taken up by cultured P. carinii in a primaquine sensitive process. Radiolabeled leucine was incorporated into the major surface glycoprotein of P. carinii. The formation of radioactive P. carinii-specific proteins indicated that the cultured organisms carried out transcription and translation and that the incorporation of amino acids was dependent upon P. carinii rather than rare HEL human embryonic lung cells. The spinner flask culture system provides convenient access to P. carinii for metabolic studies in defined medium for a period of 5-14 days after inoculation.