Gonzalez N S, Algranati I D
Instituto de Investigaciones Bioquímicas Fundación Campomar, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
Cell Mol Biol (Noisy-le-grand). 1994 Nov;40(7):907-14.
Putrescine uptake of Leishmania mexicana promastigotes is tightly regulated by polyamine intracellular concentrations. This uptake, markedly stimulated after parasite treatment with alpha-difluoromethylornithine (DFMO) for 48 to 72 hrs., was strongly repressed by exposure of Leishmania cultures to exogenous putrescine or its derivative 1,4-dimethylputrescine. In contrast, spermidine, spermine, diaminopropane and cadaverine were unable to decrease putrescine transport. Both, the uptake induction as well as its specific feedback repression by increased levels of endogenous putrescine requires protein synthesis since they were abolished after addition of cycloheximide for several hours. Our results seem to indicate that putrescine transporter is a stable and specific protein which can be reversibly inactivated by a relatively unstable repressor.
墨西哥利什曼原虫前鞭毛体对腐胺的摄取受到多胺细胞内浓度的严格调控。在用α-二氟甲基鸟氨酸（DFMO）处理寄生虫48至72小时后，这种摄取显著增加，但将利什曼原虫培养物暴露于外源性腐胺或其衍生物1,4-二甲基腐胺后，摄取则受到强烈抑制。相比之下，亚精胺、精胺、二氨基丙烷和尸胺无法降低腐胺的转运。内源性腐胺水平升高引起的摄取诱导及其特异性反馈抑制都需要蛋白质合成，因为在添加放线菌酮数小时后，这些现象就会消失。我们的结果似乎表明，腐胺转运体是一种稳定且特异性的蛋白质，它可被一种相对不稳定的阻遏物可逆地失活。
