Zilberstein D, Dwyer D M
Proc Natl Acad Sci U S A. 1985 Mar;82(6):1716-20. doi: 10.1073/pnas.82.6.1716.
Midlogarithmic phase Leishmania donovani promastigotes accumulate 2-deoxy-D-glucose (2-dGlc) and L-proline, maintaining concentration gradient factors across the surface membrane of 78.7 and 60, respectively. Cyanide (1 mM) and iodoacetate (0.5 mM) inhibited the transport of both substrates. L-proline uptake was also inhibited by 2-dGlc (10 mM). Transport of neither substrate was affected by Na+, phlorizin, or ouabain, indicating the sodium-independent transport of both systems. However, N',N'-dicyclohexylcarbodiimide (DCCD; 20 microM) significantly inhibited the transport of both 2-dGlc and L-proline (70% and 90%, respectively). The ionophores valinomycin (1 microM) and nigericin (5 microM) each partially inhibited the uptake of both substrates. In parallel experiments, nigericin and valinomycin were added concomitantly to promastigotes, each at a concentration that individually inhibited the transport of 2-dGlc and L-proline by less than 30%. Under such conditions, the transport of 2-dGlc and L-proline was inhibited by 69% and 78%, respectively. However, these ionophores had no significant effect on the promastigotes cellular ATP level. Carbonylcyanide p-(trifluoromethoxy)phenylhydrazone (FCCP; 1 microM) inhibited 2-dGlc (79%) and L-proline (85%) transport, whereas ATP levels of such cells were diminished by only 20%. Symport of D-glucose/H+ and L-proline/H+ was measured directly in cells pretreated with KCN and DCCD. Upon addition of D-glucose to such cells, a rapid movement of protons into the organisms occurred and was reversed upon addition of FCCP. Conversely, no proton movement was observed when L-glucose was added to such cells. L-proline, as D-glucose, caused a rapid influx of protons into the promastigotes, indicating that both substrates were cotransported with protons. We conclude that transport of D-glucose and L-proline in L. donovani promastigotes is protonmotive force-driven and is coupled to both delta pH and delta psi.
对数中期的杜氏利什曼原虫前鞭毛体积累2-脱氧-D-葡萄糖（2-dGlc）和L-脯氨酸，跨表面膜维持的浓度梯度因子分别为78.7和60。氰化物（1 mM）和碘乙酸盐（0.5 mM）抑制这两种底物的转运。2-dGlc（10 mM）也抑制L-脯氨酸的摄取。两种底物的转运均不受Na⁺、根皮苷或哇巴因的影响，表明这两种系统的转运均不依赖于钠。然而，N'，N'-二环己基碳二亚胺（DCCD；20 μM）显著抑制2-dGlc和L-脯氨酸的转运（分别为70%和90%）。离子载体缬氨霉素（1 μM）和尼日利亚菌素（5 μM）各自部分抑制这两种底物的摄取。在平行实验中，将尼日利亚菌素和缬氨霉素同时添加到前鞭毛体中，每种的浓度单独抑制2-dGlc和L-脯氨酸的转运均小于30%。在这种条件下，2-dGlc和L-脯氨酸的转运分别被抑制69%和78%。然而，这些离子载体对前鞭毛体细胞的ATP水平没有显著影响。羰基氰化物对-（三氟甲氧基）苯腙（FCCP；1 μM）抑制2-dGlc（79%）和L-脯氨酸（85%）的转运，而此类细胞的ATP水平仅降低20%。在经KCN和DCCD预处理的细胞中直接测量D-葡萄糖/H⁺和L-脯氨酸/H⁺的同向转运。向此类细胞中添加D-葡萄糖后，质子迅速进入生物体，并在添加FCCP后逆转。相反，当向此类细胞中添加L-葡萄糖时，未观察到质子移动。L-脯氨酸与D-葡萄糖一样，导致质子迅速流入前鞭毛体，表明这两种底物均与质子协同转运。我们得出结论，杜氏利什曼原虫前鞭毛体中D-葡萄糖和L-脯氨酸的转运是由质子动力驱动的，并且与ΔpH和Δψ均相关。
