Blum J J
Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710.
J Protozool. 1990 Nov-Dec;37(6):505-10. doi: 10.1111/j.1550-7408.1990.tb01256.x.
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.
研究了培养时间对硕大利什曼原虫前鞭毛体氧化短链、中链和长链脂肪酸速率的影响。来自5天稳定期培养物的前鞭毛体氧化几种饱和脂肪酸的速度比对数后期培养物中的细胞快约3至4倍，但[10-14C]油酸的氧化速度快9倍。将5天稳定期培养物中的细胞重悬于新鲜培养基中后，氧化速率的增加在5小时内部分逆转，在30小时内几乎完全逆转。添加乙酸盐、亮氨酸或丙氨酸对[1-14C]棕榈酸氧化有适度抑制作用，而甘油影响不大。然而，葡萄糖是[1-14C]棕榈酸和[1-14C]辛酸氧化的强力抑制剂。甘露糖和果糖也是棕榈酸氧化的强抑制剂，但半乳糖、2-脱氧葡萄糖或6-脱氧葡萄糖均未引起明显抑制。乙酸盐的抑制程度随培养时间增加而增加，而葡萄糖的抑制作用则下降。这些数据除了表明β-氧化能力随培养时间可逆增加外，还表明葡萄糖对脂肪酸氧化具有迄今未被认识的强烈且依赖于培养时间的抑制作用。
