Amoeba


Entamoeba histolytica (trophozoite)

Motility Pseudopods
Nucleus

Peripheral chromatin - usually evenly distributed and uniform in size
Karyosome - chromatin small, discrete; usually centrally located
Cytoplasm Finely granular
Inclusions RBCs occasionally
Pathogenic YES: Invasive - usually causes Amoebic dysintary


Entamoeba histolytica (cyst)

Shape Usually spherical, round to oval, with thick cell wall
Nucleus

Four mature cyst, peripheral chromatin present
Karyosome - small, discrete, usually centrally located
Cytoplasm Chromatid bodies - present; elongate bars with bluntly rounded ends, cigar-shaped

Entamoeba coli (trophozoite)

Motility Non-progressive, sluggish
Nucleus

Peripheral chromatin - irregular in size and distribution
Karyosome - chromatin is large, discrete, usually eccentrically located
Cytoplasm Coarse; often vacuolated
Inclusions May include bacteria, yeasts
Pathogenic NO


Entamoeba coli (cyst)

Shape Usually spherical
Nucleus

8 nuclei in mature cyst
Karyosome - large, discrete; usually eccentrically located
Cytoplasm Chromatid bodies less frequently present; usually splinter-like pointed ends

Iodamoeba buetschlii (trophozoite)

Motility Sluggish
Nucleus

No peripheral chromatin - reddish purple when stained
Karyosome - Large, usually centrally located
Cytoplasm Vacuolated
Inclusions Bacteria and yeasts
Pathogenic NO


Iodamoeba buetschlii (cyst)

Shape Ovoid or egg-shaped
Nucleus

No peripheral chromatin
Karyosome - large, usually eccentrically located
Cytoplasm Glycogen compact, well-defined mass. Glycogen stains dark with iodine