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Clockwise from top right: Amoeba proteus, Actinophrys sol, Acanthamoeba sp., Nuclearia thermophila., Euglypha acanthophora, neutrophil ingesting bacteria. An amoeba (/ ə ˈ m iː b ə /; less commonly spelled ameba or amœba; pl.: amoebas (less commonly, amebas) or amoebae (amebae) / ə ˈ m iː b i /), [1] often called an amoeboid, is a type of cell or unicellular organism with the ability ...
Many protozoan pathogens are human parasites, causing serious diseases such as malaria, giardiasis, toxoplasmosis, and sleeping sickness. Some of these protozoa have two-phase life cycles, alternating between proliferative stages (e.g., trophozoites ) and resting cysts , enabling them to survive harsh conditions.
Amoebozoa includes many of the best-known amoeboid organisms, such as Chaos, Entamoeba, Pelomyxa and the genus Amoeba itself. Species of Amoebozoa may be either shelled (testate) or naked, and cells may possess flagella. Free-living species are common in both salt and freshwater as well as soil, moss and leaf litter.
In Amoeba, the pseudopodia are approximately tubular, and rounded at the ends (lobose). The cell's overall shape may change rapidly as pseudopodia are extended and retracted into the cell body. An Amoeba may produce many pseudopodia at once, especially when freely floating. When crawling rapidly along a surface, the cell may take a roughly ...
The most important genera are Amoeba and Chaos, which are set apart from the others by longitudinal ridges. The best known of the species in this family is Amoeba proteus , commonly used in classrooms to demonstrate movement by pseudopodia.
The name Lobosa was chosen for these amoebae "as expressing the lobe-like character of their pseudopodial extensions". [ 5 ] As currently defined, the subphylum Lobosa includes both shelled ( testate ) and naked amoebae (gymnamoebae), but excludes some organisms traditionally regarded as "lobosean", such as Pelomyxa and Entamoeba (Amoebozoa ...
The heterolobosean pathogen Naegleria fowleri can behave as an amoeba (center) or as a flagellate (right).. An amoeboflagellate (pl. amoeboflagellates) is any eukaryotic organism capable of behaving as an amoeba and as a flagellate at some point during their life cycle.
Some examples of organisms that exhibit this type of locomotion are amoebae (such as Amoeba proteus and Naegleria gruberi, [2]) and slime molds, as well as some cells in humans such as leukocytes. Sarcomas , or cancers arising from connective tissue cells, are particularly adept at amoeboid movement, thus leading to their high rate of metastasis .