Parasitology

Research Article

Hypoxanthine: a low molecular weight factor essential for growth of erythrocytic Plasmodium falciparum in a serum-free medium

H. Asahia1 c1, T. Kanazawaa1, Y. Kajiharaa2, K. Takahashia2 and T. Takahashia3

a1 Department of Parasitology, National Institute of Health, 23-1, Toyama 1-chome, Shinjuku-ku, Tokyo 162, Japan

a2 Life Tech Division, Nihon Pharmaceutical Co. Ltd, Sumiyoshi-cho 26, Izumisano, Osaka 598, Japan

a3 Institute of Medicinal Chemistry, Hoshi University, Ebara 2-4-41, Shinagawa-ku, Tokyo 142, Japan

SUMMARY

A low molecular weight factor in a basal medium essential for erythrocytic Plasmodium falciparum development in a serum-free medium using a cell growth-promoting factor derived from adult bovine serum was detected. The factor was hypoxanthine. The optimal hypoxanthine concentration for parasite growth was between 15 and 120 μM. The contribution of hypoxanthine to increased parasite growth was clearly evident in cultures on day 4. Among various low molecular weight supplements tested, adenine, adenosine, AMP, ATP, cyclic AMP, guanine, guanosine, inosine, inosine mono-phosphate, xanthine, NAD, NADH, NADP, NADPH and deoxyguanosine triphosphate showed a similar effect to that of hypoxanthine in the serum-free culture system. On the other hand, the addition of uric acid, FAD, thymidine, uridine, orotic acid, deoxythymidine triphosphate, deoxycytidine triphosphate, deoxyadenosine triphosphate, ribose-1-phosphate, or ethanolamine was not beneficial to the parasite growth. The results presented here will not only be of practical value, but will provide important information about the developmental requirements of the parasite.

(Received December 13 1995)

(Revised February 19 1996)

(Accepted February 19 1996)

Correspondence:

c1 Corresponding author. Tel: +3 5285 1111. Fax: +3 5285 1150.

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