Entamoeba aulastomi Nöller

Abstract

1. Entamoeba aulastomi and Hexamita sp. from Haemopis sanguisuga have been cultivated in inactivated horse-serum diluted 1 : 10 in 0·5 NaCl solution + solid sterile rice-starch, and upon an inspissated horse-serum slope covered with the liquid medium + sterile rice-starch. Cysts of E. aulastomi appeared on or after the 9th day from subcultivation, but cysts of Hexamita have not appeared in the cultures.2. The amoeboid phase of E. aulastomi divides by a simple direct method, without the formation of a spindle. There is no equatorial plate. It was not possible to count the number of chromatin granules.3. The mature cyst is quadrinucleate, though occasional octonucleate cysts are found. Chromatoids are present but are absorbed before hatching. A. large glycogen vacuole is present in the uninucleate cyst. The nucleus divides by the formation of a delicate spindle but no chromosomes were found.4. E. aulastomi are not harmed by being kept at 2° C. but they die out in the 2nd subculture if kept at 30° C. and within 24 hours if kept at 37° C. The cysts also are killed at 37° C.5. If treated with N/20 HCl all amoebae are killed in less than 10 min. but the cysts are unharmed.