Chapter 3 : The Amoeba

• Trophozoite: a growing form of a protozoan that feeds, multiplies, and possesses pseudopods.
• Amoeba: they are equipped with the ability to extend their cytoplasm in the form of PSEUDOPODS ( false feet ) which allows them to move within their environment.
• Cysts: The non-feeding stage, characterized by a thick cell wall to protect itself from the environment.
• Intestinal species

  • Entamoeba histlytica
  • Entamoeba hartmanni
  • Entamoeba coli
  • Entamoeba polecki
  • Endolimax nana
  • Iodamoeba butschlii
• Extraintestinal species

  • Entamoeba gingivalis
  • Naegliria fowleri
  • Acanthamoeba species
• EXCYSTATION, the morphologic conversion from the cyst form into the trophozoite form, occurs in the ileocecal area of the intestine.
• ENCYSTATION , the conversion of trophozoite to cysts.
• Entamoeba histolytica

  (Trophozoite)

  • 8- 65 um
  • MOTILITY: Progressive, finger-like pseudopods
  • NUCLEI: 1
  • KARYOSOME: Small and Central
  • PERIPHERAL CHROMATIN: fine, evenly distributed
  • CYTOPLASM: finely granular
  • Pathogenic
  • INCLUSION : with bull's eye karyosome, Ingested RBC
• Entamoeba hartmanni

  ( Trophozoite)

  • 5-15 um
  • MOTILITY: nonprogressive ,finger-like pseudopods
  • NUCLEI: 1
  • KARYOSOME: small and central
  • PERIPHERAL CHROMATIN: fine, evenly distributed
  • CYTOPLASM: finely granular
  • non- pathogenic
  • Identically to E. Histolytica
  • INCLUSION : bacteria may be present
• Entamoeba coli

  ( Trophozoite )

  • 12- 55 um
  • MOTILITY: nonprogressive, blunt pseudopods
  • NUCLEI: 1
  • KARYOSOME : large, irregular shape, eccentric
  • PERIPHERAL CHROMATIN: unevenly distributed
  • CYTOPLASM : coarse and granulated
  • non- pathogenic
  • Most number of nuclei
  • Vacuoles containing bacteria often visible
• ENTAMOEBA HISTOLYTICA

  ( Cyst )

  • SIZE: 8- 22 um
  • SHAPE: spherical to round
  • NUCLEI: 1-4
  • KARYOSOME: small and central
  • CYTOPLASM: finely granular
  • PERIPHERAL CHROMATIN: fine, evenly distributed
  • INCLUSION: chromatids bars, diffuse glycogen mass in young cyst.
• ENTAMOEBA HARTMANNI

  ( Cyst )

  • SIZE: 5-12 um
  • SHAPE: spherical
  • NUCLEI: 1-4
  • KARYOSOME: small and central
  • CYTOPLASM: finely granular
  • PERIPHERAL CHROMATIN: fine, evenly distributed
  • INCLUSION: chromatoid bars diffuse glycogen mass in young cyst
• ENTAMOEBA COLI

  ( Cyst )

  • SIZE: 8-35 um
  • SHAPE: round to spherical
  • NUCLEI: 1-8
  • KARYOSOME: large, irregular eccentric
  • CYTOPLASM: coarse and granulated
  • PERIPHERAL CHROMATIN: unevenly distributed
  • INCLUSION: diffuse glycogen mass present in young cyst may displace NUCLEI, thin chromatoid bars, to splinter ends in young cysts.
• ENTAMOEBA POLECKI

  ( Cyst )

  • SIZE: 10-20 um
  • SHAPE: spherical to oval
  • NUCLEI: 1
  • KARYOSOME: small and central
  • CYTOPLASM: granular
  • PERIPHERAL CHROMATIN: fine, evenly distributed
  • INCLUSION: chromatoid bars, angular or pointed end. In young cyst; glycogen mass in young cysts
• ENDOLIMAX NANA

  ( Cyst )

  • SIZE: 4-12 um
  • SHAPE: spherical, ovoid, ellipsoid
  • NUCLEI: 1-4
  • KARYOSOME: large, blot-like, usually central
  • CYTOPLASM: granular and vacuolated
  • PERIPHERAL CHROMATIN: absent
  • INCLUSION: chromatins granules, nondescript small mass, diffuse glycogen mass in young cyst
• IODAMOEBA BUTSCHLII

  ( Cyst )

  • SIZE: 5-22 um
  • SHAPE: ovoid, ellipsoid, triangular
  • NUCLEI: 1
  • KARYOSOME: large, eccentric, achromatic granules on one side may present
  • CYTOPLASM: coarsely granular and vacuolated
  • PERIPHERAL CHROMATIN: absent
  • INCLUSION: well defined glycogen mass
• NAEGLIRIA FOWLERI

  ( Cyst ) SIZE: 9-12 um

  SHAPE: roundthickcellwall

  NUCLEI: 1

  KARYOSOME: large and central

  CYTOPLASM: granular vacuolated

  PERIPHERAL CHROMATIN: absent

  INCLUSION: disease condition ( primary amebic meningoencephalitis ( PAM )
• ACANTHAMOEBA SPECIES

  ( Cyst )

  • SIZE: 8-25 um
  • SHAPE: roundish with ragged edges
  • NUCLEI: 1
  • KARYOSOME: large and central
  • CYTOPLASM: disorganized granular, sometimes vacuolated
  • PERIPHERAL CHROMATIN: Absent
  • INCLUSION: double cell wall; smooth inner cell wall and outer jagged cell wall
• ENTAMOEBA GINGIVALIS

  ( no cyst form )
• IODAMOEBA BUTSCHLII

  (Trophozoite )

  • 8-22 um
  • MOTILITY: usually progressive
  • NUCLEI: 1
  • KARYOSOME: large, usually central refractive acromatic granules may present
  • PERIPHERAL CHROMATIN : Absent
  • CYTOPLASM: coarsely granular and vacuolated
  • non- pathogenic
  • INCLUSION: Cyst remains uninucleated even when mature, Bacteria; yeast cell other debris.
• ENDOLIMAX NANA ( Trophozoite )

  • 5-12 um
  • MOTILITY: sluggish, non-progressive, blunt pseudopods
  • NUCLEI: 1
  • KARYOSOME : Large, irregular, blot-like
  • PERIPHERAL CHROMATIN : absent
  • CYTOPLASM: granular and vacuolated
  • non- pathogenic
  • INCLUSION: With cross eyed cyst, Bacteria
• ENTAMOEBA POLECKI ( Trophozoite )

  • 8-25 um
  • MOTILITY: sluggish, progressive, non-progressive unidirectional
  • NUCLEI: 1
  • KARYOSOME: small and central
  • PERIPHERAL CHROMATIN: fine, evenly distributed
  • CYTOPLASM: granular and vacuolated
  • non-pathogenic
  • Parasites of pigs and monkey Ingested bacteria
• ENTAMOEBA GINGIVALIS (Trophozoite )

  • 8-20 um
  • MOTILITY : active, varying pseudopods appearance
  • NUCLEI : 1
  • KARYOSOME : centrally located
  • PERIPHERAL CHROMATIN: fine, evenly distributed
  • CYTOPLASM: finely granular
  • Non-pathogenic
  • INCLUSION: Ingested WBC, leukocytes; epithelial cell, bacteria
• Acanthamoeba species

  ( Trophozoite)

  • SIZE: 12-45 um
  • NUCLEI: 1
  • MOTILITY: sluggish, spinelike pseudopods
  • KARYOSOME: large
  • CYTOPLASM: granular and vacuolated
  • PERIPHERAL CHROMATIN: absent
  • INCLUSION: trophozoite slowly motile
  • Free- living pathogenic
• NAEGLERIA FOWLERI ( TROPHOZOITE )

  • SIZE: 8-22 um
  • MOTILITY : sluglike, blunt pseudopods
  • NUCLEI: 1
  • KARYOSOME: large and usually centrally located
  • CYTOPLASM: granular and vacuolated
  • PERIPHERAL CHROMATIN: absent
  • INCLUSION: trop rapidly motile, with flagellate form