Week 3: Protozoan Flashcards
known for ameboid characteristics, equipped with the ability to extend their cytoplasm in the form of pseudopods (often referred to as false feet), which allows them to move within their environment.
Amoeba
_____, _____, and _____ represent the important amoeba in humas
Entamoeba, Naegleria, Acanthamoeba
How many species of the genus Entamoeba are capable of infecting man?
Six (6) species
What is the only pathogenic in species of the genus Entamoeba?
Entamoeba histolytica
-a zoonotic protozoan of pigs and monkey
-known to be commensals in humans
-its infections are asymptomatic and seldomly cause diarrhea
Entamoeba polecki
_____ and _____ are free-living protozoans found mainly in freshwater
Naegleria, Acanthamoeba
What are the two morphologic forms?
Trophozoite and Cysts
-characteristically delicate and fragile because of their ability to produce and use pseudopods, motile
-replication only occurs in the trophozoite stage; it is accomplished by multiplication of the nucleus via asexual binary fission
Trophozoite
the morphologic conversion from the cyst form into the trophozoite form, occurs in the ileocecal area of the intestine
Excystation
the nonfeeding stage characterized by a thick protective cell wall designed tom protect the parasite from the harsh outside environment when deemed necessary
Cysts
the conversion of trophozoites to cysts, occurs in the intestine when the environment becomes unacceptable for continued trophozoite multiplication
Encystation
-It is frequently affecting invertebrate and vertebrate organisms.
-Characterized by vesicular nucleus with a comparatively small karyosome located at or near its center and with varying characteristics of the peripheral chromatin attached to the nuclear membrane.
The genus Entamoeba
morphologically similar and can only be differentiated by isoenzyme analysis, restriction fragment length polymorphism, typing
with monoclonal antibodies, and polymerase chain reaction
E. histolytica, E.dispar, and E. moshkovskii
considered to be the “small race” of E. histolytica because of its size.
E. hartmanni
*All entamoeba are lumen-dwelling protozoans except _____.
*All are non-pathogenic except _____.
*Cystic stage is the infective stage except _____.
E. gingivalis, E. histolytica., E. gingivalis.
First described by a young Russian peasant named _____, from a patient with diarrheic stool. A species-complex amoeba considered to cause _____ and _____ worldwide.
Entamoeba histolytica (Losch, amoebic dystentery, liver abscess)
_____ must be differentiated from pathogenic E. histolytica to avoid unnecessary treatment of patients infected with non-pathogenic species
Commensal Amebae
has a spherical nucleus with a distinct nuclear membrane lined with chromatin granules and a small karyosome found near the center of the nucleus. Trophozoites usually have only one nucleus
genus Entamoeba
has a vesicular nucleus with a relatively large, irregularly-
shaped karyosome anchored to the nucleus by achromatic fibrils.
genus Endolimax
characterized by a large, chromatin-rich karyosome surrounded by a layer of achromatic globules and anchored to the nuclear membrane by achromatic fibrils
genus lodamoeba
Originally proposed by Emile Brumpt in 1925
Entamoeba dispar & Entamoeba moshkovskii
*capable of causing focal intestinal lesions in experimental animals such as kittens, gerbils, and guinea pigs
*does not cause symptomatic disease, nor does it elicit the production of serum antibodies
*approximately nine times more prevalent than E. histolytica, and
together they infect about 10% of world’s population
E. dispar
is cosmopolitan in distribution, and is considerably more common than other human amebae.
Entamoeba coli
Has now attained general acceptance as the name for the amebae formerly designated as “small race” E. histolytica
Entamoeba hartmanni
First reported as an intestinal parasite of pigs and monkeys, has been found occasionally in humans.
Entamoeba polecki
often found in pyorrheal pockets between the teeth and gums and in the tonsillar crypts. Existing as a scavenger, it’s trophozoites feed on disintegrated cells and multiply by binary fission
Entamoeba gingivalis
receives its generic name from the characteristic glycogen vacuoles of the cyst stage, which are so prominent that in iodine stains the cysts seem to contain little else
lodamoeba bütschlii
The most common of the smaller intestinal amebae, Endolimax is usually encountered with about the same frequency as is E. coli
Endolimax nana
