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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 ...
Amoeba, Entamoeba histolytica uses holozoic nutrition. Holozoic nutrition (Greek: holo -whole ; zoikos -of animals) is a type of heterotrophic nutrition that is characterized by the internalization ( ingestion ) and internal processing of liquids or solid food particles. [ 1 ]
Food enveloped by the Amoeba is stored in digestive organelles called food vacuoles. Amoeba, like other unicellular eukaryotic organisms, reproduces asexually by mitosis and cytokinesis. Sexual phenomena have not been directly observed in Amoeba, although sexual exchange of genetic material is known to occur in other Amoebozoan groups. [15]
The advantage of the Colonial Theory hypothesis is that it has been seen to occur independently in 16 different protoctistan phyla. For instance, during food shortages the amoeba Dictyostelium groups together in a colony that moves as one to a new location. Some of these amoeba then slightly differentiate from each other.
Amoeba proteus is a large species of amoeba closely related to another genus of giant amoebae, Chaos. As such, the species is sometimes given the alternative scientific name Chaos diffluens. [1] [2] Amoeba proteus in locomotion. This protozoan uses extensions called pseudopodia to move and to eat smaller unicellular organisms.
Both single-celled and multi-cellular eukaryotic phototactic organisms have a fixed shape, are polarized, swim in a spiral and use cilia for swimming and phototactic steering. Signalling can happen via direct light-triggered ion currents, adenylyl cyclases or trimeric G-proteins. The photoreceptors used can also be very different (see below).
An amoeba of the genus Mayorella (Amoebozoa, Discosea). Amoebozoa is a large and diverse group, but certain features are common to many of its members. The amoebozoan cell is typically divided into a granular central mass, called endoplasm, and a clear outer layer, called ectoplasm.
Nucleariida is a group of amoebae [1] with filose pseudopods, known mostly from soils and freshwater.They are distinguished from the superficially similar vampyrellids mainly by having mitochondria with discoid cristae, in the absence of superficial granules, and in the way they consume food.