Isolation of second-generation schizonts of avian coccidia and their use in biochemical investigations

Abstract

Summary: A technique is described for the isolation of a pure suspension of second-generation schizonts ofEimeria necatrixandE. tenella. Most of the schizonts appeared viable as judged by their ability to exclude Trypan blue and the use of this criterion is examined. They were able to metabolize radio-isotope labelled glucose and accumulate thiamine against a concentration gradient. A formula allowing detailed consideration of the latter process is introduced. Crude extracts of these schizonts exhibited serine hydroxymethyl transferase activity which is significantly different from that of the host tissue in terms of optimal pH (8·3 for the parasite and 7·8 for the avian intestinal cells) and Michaelis constant (approximately 2·6 × 10⁻³mand 0·6 × 10⁻³mrespectively). Differences in response to potential inhibitors are also shown.