Which feature identifies Iodamoeba bütschlii cysts?

• A. Blunt chromatoidal bars
• B. Four nuclei with large karyosomes
• C. Many ingested bacteria
• D. A well-defined glycogen mass

Answer: (D)

Iodamoeba bütschlii cysts are best identified by a large, well-defined glycogen mass inside the cyst. This glycogen body is a distinctive feature that stains with iodine, giving the cyst a characteristic appearance and helping separate this species from others that may have multiple nuclei or different internal contents. The cysts typically show a single nucleus, and the prominent glycogen mass dominates the interior, which is not a trait shared by cysts with four nuclei or with numerous ingested bacteria. Chromatoidal bars and multiple nuclei are features of other amoebic cysts, so they aren’t the reliable identifiers for Iodamoeba bütschlii.