Amoebas Flashcards
Protozoa
Organisms in a number of phyla
Highly diverse group
unicellular, eukaryotic
Trophozoite
Active feeding stage of a protozoan (vegetative stage)
Cyst
Environmentally resistant dormant stage of protozoan
-spherical, with a thick cyst wall
Pellicle
Entire outer envelope covering protozoa
Glycocalyx
Carbohydrate above plasma membrane
Endosome (karyosome)
Like a nucleolus (but does not dissapear during mitosis)
Chromatoidal bars
Chromatoid bars or bodies are masses containing RNA found in young entamoeba cysts
Entamoeba Histolytica: Cysts
Asymptomatic infection trophozites encyst as feces forms
spherical to oval in shape
Organism is associated with flask-shaped lesions in intestines
a. entameba histolytica
b. entameba coli
c. naegleria fowleri
d. acanthameba spp.
Entameba Histolytica
Organism is not a parasite, but a commensal
a. entameba histolytica
b. entameba coli
c. naegleria fowleri
d. acanthameba spp.
Entameba Coli
Outbreaks in immunocompetent people are often associated with contaminated contact lens solutions
a. entameba histolytica
b. entameba coli
c. naegleria fowleri
d. acanthameba spp.
Acanthameba spp.
Infection is associated with warm water lakes and streams, especially when water is forced up the nose.
a. entameba histolytica
b. entameba coli
c. naegleria fowleri
d. acanthameba spp.
Naegleria Fowleri
Centrally located endosome in nucleus, early cysts with blunt chromatoid bars, and mature cysts with 4 nuclei
a. entameba histolytica
b. entameba coli
c. naegleria fowleri
d. acanthameba spp.
Entameba Histolytica
Entamoeba Coli
Lives on intestinal bacteria, other protozoa, yeast, maybe an occasional host cell
Entamoeba Coli: Trophozoites
eccentrally located endosome
thicker, darker staning chromatin granules
food vacuoles often contain bacteria
Entamoeba Histolytica: Trophozoites
centrally located endosome
thin fibrils entending to nuclear membrane
food vacuoles common, some may contain host red blood cells
Infection: EH
cyst pass in feces, must be ingested (mouth-butt route)
contaminated water supplies, filth flies, cockroaches
sexual practices
use of human feces (night soil) as fertilizer
Symptoms: EH
Diarrhea, abdominal pain, cramps , vomiting , bloody diarrhea
not typically a disease of children
more common in tropics
Treatment: EH
Metranidazole, several other drugs
Antibiotics may be used to treat accompanying secondary bacterial infections
Entamoeba Coli: Cysts
ecentrally located endosome; thicker dark staining chromatin granules
more than 4 nuclei (8 in mature cyst)
chromatodial bars with jagged, splintered ends in young cysts
Naegleria fowleri
ameba trael via olfactory nerves, through cribriform plate to brain
common aquatic ameba but infection is rare
naegleria is sensitive to amphotericin b
Acanthameba Spp
attacks the cornea of the eye
immunocompromised patients may cause skin, lung, CNS infections
