METABOLISM OF BABESIA PARASITES IN VITRO. COMPARISON OF SEVERAL ZWITTERION BUFFERS FOR THE IN VITRO INCUBATION OF BARESIA RODHAINI

Abstract

Summary. The effect on the haemoprotozoan parasite Babesia rodhaini of adding a zwiiterion buffer, HEPES. to a basal medium was studied by comparing the glucose uptake, ATP concentration, medium pH and infectivity of parasitized rat erythrocytes every 4 h during 24 h incubalion in either Krebs Ringer phosphate (KRP) or KRP plus 28 mM HEPES. KRP plus HEPES was found to be superior to KRP for the maintenance of glucose uptake, erythrocyte ATP concentration, medium pH ynd infectivity of the parasite.Having established that HEPES improved the basal KRP medium. HEPES was then compared lo three olher buffers TES. BES and TRIS. to determine their relative effects on B. rodhaini during 18 h of incubation. At 28 and 56 mM concentration there was no significant difference in glucose uptake or lactate production among the 4 buffers. However, TES maintained the medium pH best, and BES preserved the infectivity of Ihe parasite best. Further comparison of TES and BES at 10, 20. 30 and 40 mM established 40 mM TES to be best for buffering the pH of the medium and maintaining infectivity of B. rodhaini.

METABOLISM OF BABESIA PARASITES IN VITRO. AMINO ACID PRODUCTION BY BABESIA RODHAINI COMPARED TO PLASMODIUM BERGHEI

“…The most likely one is that the use of 40 mM TES buffer during 4 h incubation provided a much more favourable environment for metabolic activity by the parasites than did 28 mM TES used during 18 h incubation. Barry (1982b) showed that 40 mM TES improved the survival rate of B. rodhaini up to 10-fold compared to 28 mM TES during 18 h of incubation.…”

“…In the 4 and 18 h incubation experiments in which individual amino acids were estimated, the medium was supplemented with 40 and 28 mM tris (hydroxymethyl) methylamino ethane sulphonic acid (TES), respectively, to increase buffering capacity (Barry, 1982b).…”