Louassini M, Foulquié M R, Benítez R, Adroher F J
Department of Parasitology, Faculty of Pharmacy, University of Granada, Spain.
Parasitol Res. 1999 Apr;85(4):300-6. doi: 10.1007/s004360050552.
This paper follows the development in the activity of the key enzymes of glycolysis and dehydrogenases of the pentose phosphate shunt throughout the in vitro growth and metacyclogenesis of two human strains of Leishmania infantum - one visceral (VL) and the other cutaneous (CL) - together with changes in the glucose, ammonium, and proton concentrations in the culture medium. In the first stage, ammonium was generated and no glucose was consumed. Later on, all the glucose was consumed and, finally, ammonium was generated again. The ammonium concentration increased 16- and 21-fold in cultures of VL and CL strains, respectively. The activities of the glycosomal enzymes hexokinase and phosphofructokinase differed in each strain, always being higher in CL than in VL and increasing throughout the culture period in CL while decreasing in VL. This probably indicates a different capability to adapt to the culture medium conditions. The activities of the pentose phosphate shunt enzymes examined indicate that 6-phosphogluconate dehydrogenase is possibly a rate-limiting enzyme for this pathway. Pyruvate kinase is a cytosolic control enzyme of glycolysis in trypanosomatids, and its activity decreased throughout the growth and differentiation of both strains of L. infantum, as occurs in other trypanosomatids. It was also observed that glucose catabolism was more active in the cutaneous strain than in the visceral one.
本文追踪了两种婴儿利什曼原虫人源菌株（一种为内脏利什曼病菌株，另一种为皮肤利什曼病菌株）在体外生长和发育为成熟体的过程中，糖酵解关键酶和磷酸戊糖途径脱氢酶活性的变化，以及培养基中葡萄糖、铵和质子浓度的变化。在第一阶段，产生了铵但未消耗葡萄糖。随后，所有葡萄糖被消耗，最后又再次产生了铵。在VL和CL菌株的培养物中，铵浓度分别增加了16倍和21倍。糖体酶己糖激酶和磷酸果糖激酶的活性在每个菌株中有所不同，CL菌株中的活性始终高于VL菌株，并且在CL菌株的整个培养期间都在增加，而在VL菌株中则下降。这可能表明它们适应培养基条件的能力不同。所检测的磷酸戊糖途径酶的活性表明，6-磷酸葡萄糖酸脱氢酶可能是该途径的限速酶。丙酮酸激酶是锥虫中糖酵解的胞质控制酶，其活性在两种婴儿利什曼原虫菌株的生长和分化过程中均下降，其他锥虫也有这种情况。还观察到，皮肤菌株中的葡萄糖分解代谢比内脏菌株更活跃。
