A Helical Structure in Ribonucleoprotein Bodies of Entamoeba invadens

Abstract

THERE have been conflicting reports in the literature about the chemical nature and origin of chromatoid and related bodies found in the cytoplasm of certain protozoa^1–8 and in the spermatogenic cells of certain crustaceans⁹, insects^10–11, cyclostomes⁹, reptiles¹², birds⁹, and mammals^13–15. Of special importance is the recent work of Barker^1,16. This investigator has shown in his cytochemi-cal and electron microscope studies that chromatoid bodies in Entamoeba invadens, a parasite of snakes, are composed of ribonucleic acid and protein and that chromatoid bodies arise by a process of aggregation tof small groups of 250–300 Å units which form polycrystalline masses in precysts and early cysts. The purposes of this report are to show: (A) that the chromatoid bodies are also found in axenically grown trophozoites, where there is no cyst formation, and (B) that the ribonucleoproteins within the chromatoid bodies are arranged in a helical pattern.