Isolate-dependent differences in the oxidative metabolism of Trypanosoma cruzi epimastigotes.
Epimastigote cultures of the two cloned Trypanosoma cruzi stocks, CA-I/72 and HO-3/15, grown under identical conditions, differ both qualitatively and quantitatively in their cytochrome content. The CA-I/72 stock has a four-fold higher cytochrome b content (19.2 nM (mg protein)-1) than the HO-3/15 stock (4.9 nM (mg protein)-1). Cytochrome o is present at 29 nM (mg protein)-1 in the CA-I/72 stock but is below detectable limits in the HO-3/15 stock. There is no inter-stock difference in oxygen utilization (12-15 nM O2 min-1 (mg protein)-1) during exponential growth. However, stationary phase CA-I/72 epimastigotes utilize twice as much oxygen as HO-3/15 epimastigotes. Oxygen utilization by HO-3/15 epimastigotes incubated in Dulbecco's phosphate buffer solution (starvation conditions), was stimulated earlier and to higher levels by the addition of glucose than by CA-I/72 epimastigotes under identical conditions. Under starvation conditions and with the cytochrome chain partially inhibited by antimycin A,(anti-A) the addition addition of glucose also increased oxygen utilization by CA-I/72 epimastigotes. In contrast, anti-A did not influence glucose-stimulated oxygen utilization by HO-3/15 epimastigotes. Following partial inhibition with anti-A, salicylhydroxamic acid produced an additional 50% inhibition in oxygen utilization in both stocks irrespective of the growth phase of the organisms. These data indicate that marked intra-specific differences in oxidative metabolism exist within the T. cruzi population and that an alpha-glycerophosphate oxidase or similar salicylhydroxamic acid-inhibitable compound may be present in the organism.
Engel
J C
JC
Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.
Doyle
P S
PS
Dvorak
J A
JA
D000818:Animals; D003580:Cytochromes / Q000032:analysis; D014644:Genetic Variation; D005947:Glucose / Q000502:physiology; D007501:Iron / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects / Q000235:genetics*; D012457:Salicylamides / Q000494:pharmacology; D014344:Trypanocidal Agents / Q000494:pharmacology; D014349:Trypanosoma cruzi / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
D003580:Cytochromes; D012457:Salicylamides; D014344:Trypanocidal Agents; C005703:salicylhydroxamic acid; D007501:Iron; D005947:Glucose