Stimulated transport of adenosine, guanosine and hypoxanthine in Crithidia luciliae: Metabolic machinery in which the parasite has a distinct advantage over the host
| Autor: | Rachel E. Day, Annette M. Gero, Simone T. Hall |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Purine
Adenosine Aminoisobutyric Acids Guanosine Purine nucleoside phosphorylase Deoxyglucose Culture Media Serum-Free chemistry.chemical_compound Inosine Monophosphate Nucleotidases Crithidia medicine Animals Crithidia luciliae Cycloheximide Purine metabolism Hypoxanthine Protein Synthesis Inhibitors biology Hypoxanthine transport Biological Transport biology.organism_classification Infectious Diseases Biochemistry chemistry Parasitology medicine.drug |
| Zdroj: | International Journal for Parasitology. 27:241-249 |
| ISSN: | 0020-7519 |
| DOI: | 10.1016/s0020-7519(96)00153-1 |
| Popis: | Nutritional insufficiency is a common environmental extreme to which parasitic protozoa are routinely exposed. In this study of purine salvage mechanisms we illustrate some successful adaptations of the parasite Crithidia luciliae to its environment, particularly in the case of purine stress. In purine-depleted conditions, the insect trypanosome C. luciliae has the ability to increase the rates of transport of adenosine, guanosine and hypoxanthine and the activity of the exoenzyme 3'nucleotidase (3'NTase) during the growth cycle. The dramatic increase in these activities appears after a 72-h period in culture. The increased activity of the purine transporters and 3'NTase could be suppressed by addition to the medium of a purine supplement such as adenosine or hypoxanthine (100 microM). Under conditions where the concentration of purines in the medium could be closely regulated, C. luciliae grown in purine-replete medium (or = 75 microM purine) exhibited low rates of purine transport and activity of 3'NTase. In comparison, parasites transferred to medium with a low purine source (or = 7.5 microM adenosine) had levels of adenosine, guanosine and hypoxanthine transport elevated 25-40-fold. The results link the simultaneous increase in activity of the nucleoside and base transporters, 3'NTase activity and a general increase in the purine salvage of C. luciliae to the concentration of purines available at any time to the parasite. |
| Databáze: | OpenAIRE |
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