Effects of culture age and hexoses on fatty acid oxidation by Leishmania major.
The effect of culture age on the rate of oxidation of short-, medium, and long-chain fatty acids by Leishmania major promastigotes was investigated. Promastigotes from 5-day stationary phase cultures oxidized several saturated fatty acids about 3-to-4-fold faster than cells from late log phase cultures, but [10-14C]oleate was oxidized 9-fold faster. The increase in rate of oxidation was partially reversed within 5 h and almost completely reversed within 30 h after resuspending cells from a 5-day stationary culture in fresh medium. Addition of acetate, leucine, or alanine caused moderate inhibitions of [1-14C]palmitate oxidation, while glycerol had little effect. Glucose, however, was a powerful inhibitor of the oxidation of [1-14C]palmitate and of [1-14C]octanoate. Mannose and fructose were also strong inhibitors of palmitate oxidation, but neither galactose, 2-deoxyglucose or 6-deoxyglucose caused appreciable inhibition. The extent of inhibition by acetate increased with increasing culture age, whereas inhibition by glucose decreased. In addition to demonstrating a reversible rise in beta-oxidation capacity with culture age, these data also demonstrate a hitherto unrecognized strong and culture age-dependent inhibition of fatty acid oxidation by glucose.
Blum
J J
JJ
Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710.
D000085:Acetates / Q000378:metabolism; D000409:Alanine / Q000378:metabolism; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D002470:Cell Survival; D005227:Fatty Acids / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006601:Hexoses / Q000378:metabolism*; D007895:Leishmania tropica / Q000378:metabolism / Q000502:physiology*; D007930:Leucine / Q000378:metabolism; D010084:Oxidation-Reduction
D000085:Acetates; D005227:Fatty Acids; D006601:Hexoses; D002245:Carbon Dioxide; D007930:Leucine; D005947:Glucose; D000409:Alanine