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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 ...
Similarly to some of the white blood cells of vertebrates, in many species amebocytes are found in the blood or body fluid (e.g. as the blood cells of Limulus, the horseshoe crab) [1] and play a role in the defense of the organism against pathogens. Depending on the species, an amebocyte may also digest and distribute food, dispose of wastes ...
As long as the cell has a way to grapple the substratum, repetition of this process guides the cell forward. Inside the amoeba, there are proteins that can be activated to convert the gel into the more liquid sol state. Cytoplasm consist largely of actin and actin is regulated by actin-binding protein. Actin binding proteins are in turn ...
The central body tends to vary between brick red, orange, reddish yellow, brown, or green. [4] [6] [7] Numerous long colourless pseudopodia extend in all directions giving trophozoites an isodiametric morphotype. [3] These pseudopodia can be as long as three times the diameter of the cell body and may be branched or unbranched. [6]
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 monopodial form, with a single dominant pseudopod deployed in the direction of movement.
Because Acanthamoeba does not differ greatly at the ultrastructural level from a mammalian cell, it is an attractive model for cell-biology studies; it is important in cellular microbiology, environmental biology, physiology, cellular interactions, molecular biology, biochemistry, and evolutionary studies, due to the organisms' versatile roles ...
Life cycle. Dictyostelium discoideum is a species of soil-dwelling amoeba belonging to the phylum Amoebozoa, infraphylum Mycetozoa.Commonly referred to as slime mold, D. discoideum is a eukaryote that transitions from a collection of unicellular amoebae into a multicellular slug and then into a fruiting body within its lifetime.
Amoebae exhibit “open mitosis” during which the nuclear membrane breaks down, as is typical of animal cells, before reassembling after telophase. Plasmodia exhibit “closed mitosis” during which the nuclear membrane remains intact. This presumably prevents nuclear fusion from occurring during mitosis in the multinucleate syncytium.