Ogbunude P O, al-Jaser M H, Baer H P
Department of Biological and Medical Research, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.
Exp Parasitol. 1991 Oct;73(3):369-75. doi: 10.1016/0014-4894(91)90109-a.
The nucleoside transport characteristics of two strains of Leishmania donovani promastigotes were studied. Strain S1, growing in fully defined medium, and strain S2 (MHOM/ET/67/HA3) both transported adenosine and inosine, but only strain S1 transported uridine and thymidine. Competition studies in the presence of 100 microM of unlabeled adenosine, inosine, guanosine, 2'-deoxyadenosine, tubercidin, formycin B, 3'-deoxyinosine as well as uridine, thymidine and cytidine, with either 1 microM [3H]adenosine or [3H]inosine as permeant, were carried out. The inhibition profile with [3H]inosine as permeant was essentially identical in S1 and S2 promastigotes, indicating that the same inosine transporter was present in both strains. However, with [3H] adenosine as permeant, significant differences were noted between the two strains. Thus, only adenosine, 2'-deoxyadenosine, tubercidin, uridine, and thymidine were strongly inhibitory in S1 promastigotes, while essentially all nucleosides tested were effective in S2 promastigotes. This indicates that adenosine transport in S2 promastigotes seems to involve a transporter differing from that described for S1 promastigotes.
对两株杜氏利什曼原虫前鞭毛体的核苷转运特性进行了研究。在完全限定培养基中生长的S1株和S2株（MHOM/ET/67/HA3）均能转运腺苷和肌苷，但只有S1株能转运尿苷和胸苷。以1μM [3H]腺苷或[3H]肌苷作为通透剂，在存在100μM未标记的腺苷、肌苷、鸟苷、2'-脱氧腺苷、杀结核菌素、间型霉素B、3'-脱氧肌苷以及尿苷、胸苷和胞苷的情况下进行了竞争研究。以[3H]肌苷作为通透剂时，S1和S2前鞭毛体的抑制谱基本相同，表明两株均存在相同的肌苷转运体。然而，以[3H]腺苷作为通透剂时，两株之间存在显著差异。因此，只有腺苷、2'-脱氧腺苷、杀结核菌素、尿苷和胸苷对S1前鞭毛体有强烈抑制作用，而基本上所有测试的核苷对S2前鞭毛体均有效。这表明S2前鞭毛体中的腺苷转运似乎涉及一种与S1前鞭毛体中描述的转运体不同的转运体。
