| Abstract: | SYNOPSIS. In a study of in vitro maintenance of the trophonts and sporozoites of the cephaline gregarine, Pyxinia crystalligera, a basal medium consisting of salts, reducing agents, and antibiotics was supplemented by fetal bovine serum, serum protein fraction IV-4, or protein hydrolysates. Motility was used as the viability criterion. The tests were terminated when viability was ～30% of the original inoculum. Two-week survival of trophonts was observed with 0.75% protein fraction, 80% of organisms remaining viable at the end of 1 week. Similar results were noted with 2% casein hydrolysate. With lactalbumin hydrolysate and Casamino acids trophonts remained viable for 6 days, and with fetal bovine serum the results were similar to those obtained with lower concentrations of protein fraction IV-4. Sporozoites remained motile for up to 5 days in the basal medium supplemented by both protein fraction IV-4 and diluted haemocoelic contents of the host, Dermestes vulpinus, but only for 3 days or less in that supplemented by the protein fraction alone. The characteristic crystals of trophonts were dissolved or possibly utilized during in vitro maintenance. A new type of crystal, however, was observed in forms kept in the presence of higher protein hydrolysate concentrations. Smaller trophonts were more adaptable to maintenance than larger ones, for rapid depletion of paraglycogen and resorption of the deutomerite often was observed in the latter. Results of cytochemical tests for carbohydrates, neutral lipids, and proteins indicated that the trophonts were capable of paraglycogen synthesis in vitro. |
