2: COMMENSAL AMEBAE Flashcards
The three genera
of intestinal amebae can be differentiated
through the morphological features of their
________.
nuclei
Trophozoites usually have only ______ nucleus.
one
The genus _____________ has a vesicular nucleus with a relatively large, irregularly-shaped karyosome anchored to the nucleus by achromatic fibrils.
Endolimax
The genus ____________ is characterized by a large, chromatin-rich karyosome surrounded by a layer of achromatic globules and anchored to the nuclear membrane by achromatic fibrils.
Iodamoeba
All species have the following stages:
trophozoite, precyst, cyst, and metacystic
trophozoite; (with the exception of Entamoeba gingivalis)
has no cyst stage, and does not inhabit the intestines
Entamoeba gingivalis
Excystation occurs in the alkaline environment of the ________________________
lower small intestines
__________________colonize the large intestines and live on the mucus coat covering the intestinal mucosa
Metacystic trophozoites
____________________ is morphologically
similar to E. histolytica, but their DNA and
ribosomal RNA are different
Entamoeba dispar (isoenzyme pattern is different)
It is a non-pathogenic species
that is morphologically indistinguishable
from E. histolytica and E. dispar, but differs
from them biochemically and genetically
Entamoeba moshkovskii i
E. moshkovskii is also physiologically unique—it being _______________ , able to grow at room temperature (25-30°C optimum), able to survive at temperatures ranging from 0 to 41°C.
osmotolerant
All human isolates have been found
to belong to one group___________.
“ribodeme 2
The appearance of _____________ is relatively
similar to that of E. histolytica apart from its
smaller size.
E. hartmanni
_____________ does not ingest red blood cells.
E. hartmanni
______________ is cosmopolitan in
distribution, and is considerably more common than other human amebae.
Entamoeba coli
E. coli can be differentiated from E. histolytica trophozoite by the following features:
1) a more vacuolated or granular endoplasm with bacteria and debris, but no red blood cells;
2) a narrower, less-differentiated ectoplasm;
3) broader and blunter pseudopodia used more for feeding than locomotion;
4) more sluggish, undirected movements; and
5) thicker, irregular peripheral
chromatin with a large, eccentric karyosome in the nucleus
An E. coli cyst may be differentiated from
E. histolytica by:
1) its larger size (10 to 35 μm in diameter),
2) more nuclei (eight versus four in E. histolytica),
3) more granular cytoplasm, and
4) splinter-like chromatoidal bodies
__________________ is a parasite found in
the intestines of pigs and monkeys.
Entamoeba polecki
E. polecki can be distinguished from E.
histolytica in that the former’s cyst is:
- consistently uninucleated
- chromatoidal bars are frequently angular or pointed.
__________________, which is found in apes
and monkeys, is morphologically identical to
E. polecki.
Entamoeba chattoni
Identification of E. chattoni was done via ______________
isoenzyme analysis
___________________ can be found in the mouth.
Entamoeba gingivalis
It moves quickly, and has numerous
blunt pseudopodia.
Entamoeba gingivalis
________________ lives on the surface of
gum and teeth, in gum pockets, and sometimes in the tonsillar crypts. They are abundant in cases of oral disease.
E. gingivalis
