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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 ...
These are roughly cylindrical with granular endoplasm and no subpseudopodia, as found in other members of the class Tubulinea. During locomotion one pseudopod typically becomes dominant and the others are retracted as the body flows into it. In some cases the cell moves by "walking", with relatively permanent pseudopodia serving as limbs.
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.
Many unicellular protists, particularly protozoans, are motile and can generate movement using flagella, cilia or pseudopods. Cells which use flagella for movement are usually referred to as flagellates, cells which use cilia are usually referred to as ciliates, and cells which use pseudopods are usually referred to as amoeba or amoeboids.
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 .
In total, the researchers found 16 plastic fibers and particles in the tissues. The smallest were slimmer than the diameter of a human red blood cell, which measures about 8 micrometers. The most ...
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.