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Mechanism of Pyrimethamine Resistance in Recent Isolates of Plasmodium Falciparum

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Specialty Pharmacology
Date 1984 Nov 1
PMID 6393866
Citations 12
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Abstract

Clones of Plasmodium falciparum prepared from recent isolates of infected blood were studied to determine the molecular mechanism of naturally occurring pyrimethamine resistance. Total DNA, as well as thymidylate synthetase and dihydrofolate reductase activities, were characterized from these lines. Restriction analysis of DNA from pyrimethamine-susceptible and -resistant lines of the parasite showed no obvious amplification of any DNA fragment. Further, analysis of DNA from resistant and susceptible lines by centrifugation in cesium chloride-ethidium bromide revealed no extrachromosomal amplification in the resistant line. Comparison of the dihydrofolate reductase enzyme activity in the two lines revealed similar KmS for substrate but a large difference in the inhibition constant for pyrimethamine. Additionally, the enzyme from the resistant line was considerably more stable in vitro than the corresponding enzyme from the susceptible line. The thymidylate synthetase activity in the two lines was similar and unaffected by pyrimethamine. The mechanism of drug resistance in this isolate involves altered properties of the dihydrofolate reductase conferring both a different affinity for the drug and increased stability.

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References
1.
Roberts D . An isotopic assay for thymidylate synthetase. Biochemistry. 1966; 5(11):3546-8. DOI: 10.1021/bi00875a022. View

2.
FERONE R, BURCHALL J, HITCHINGS G . Plasmodium berghei dihydrofolate reductase. Isolation, properties, and inhibition by antifolates. Mol Pharmacol. 1969; 5(1):49-59. View

3.
Carter R, McGregor I . Enzyme variation in Plasmodium falciparum in the Gambia. Trans R Soc Trop Med Hyg. 1973; 67(6):830-7. DOI: 10.1016/0035-9203(73)90011-4. View

4.
TRAGER W, Jensen J . Human malaria parasites in continuous culture. Science. 1976; 193(4254):673-5. DOI: 10.1126/science.781840. View

5.
Kan S, Siddiqui W . Comparative studies on dihydrofolate reductases from Plasmodium falciparum and Aotus trivirgatus. J Protozool. 1979; 26(4):660-4. DOI: 10.1111/j.1550-7408.1979.tb04216.x. View