title: Pteroylpolyglutamate synthesis by lung- and culture-derived Pneumocystis carinii.
abstract: Pneumocystis carinii synthesizes folates de novo from exogenous p-aminobenzoic acid (pABA). Lung-derived organisms take up [3H]pABA in vitro except in the presence of sulfamethoxazole. Supernatants from spinner-flask cultures take up [3H]pABA if they were inoculated with lungs from infected rats, but not if they were inoculated with lungs from uninfected rats. P. carinii folates consist primarily of pteroylpentaglutamates. Plasmodium falciparum, in contrast, contains primarily pteroyltetraglutamates. Culture-derived organisms synthesize folates at a four-fold higher specific activity than lung-derived organisms, possibly because they contain less contaminating lung debris. These data suggest that P. carinii remains metabolically active in culture for at least 4 days.
authors.affiliation: Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor 48109-2029, USA.
authors.forename: Y L
authors.initials: YL
authors.lastname: Hong
authors.forename: M S
authors.initials: MS
authors.lastname: Bartlett
authors.forename: S
authors.initials: S
authors.lastname: Queener
authors.forename: J W
authors.initials: JW
authors.lastname: Smith
authors.forename: M
authors.initials: M
authors.lastname: Shaw
authors.forename: S R
authors.initials: SR
authors.lastname: Meshnick
mesh_terms: D010129:4-Aminobenzoic Acid / Q000378:metabolism; D000818:Animals; D066298:In Vitro Techniques; D008168:Lung / Q000382:microbiology; D009172:Mycology / Q000379:methods; D011010:Pneumocystis / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D011020:Pneumonia, Pneumocystis / Q000382:microbiology; D011624:Pteroylpolyglutamic Acids / Q000096:biosynthesis*; D051381:Rats
chemical_list: D011624:Pteroylpolyglutamic Acids; D010129:4-Aminobenzoic Acid