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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.
The amoeba moves towards the signal. The amoeba secretes more cAMP to boost the signal. The effect of this is to relay the signal throughout the nearby population of amoebae and cause inward movement to the area of highest cAMP concentration. Within an individual cell, the mechanism is as follows:
Note that an apogamic amoeba retains its matA1 mating type specificity and can still fuse sexually with an amoeba of a different mating type to form a diploid heterozygous plasmodium—another characteristic that facilitates genetic analysis. [citation needed] P. polycephalum amoebae growing on lawns of live E. coli.
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.
Another unique example of symbiosis occurs in the social amoeba Dictyostelium discoideum. D. discoideum and other social amoeba differ from free living Acanthamoeba in that instead of encysting, they undergo a social cycle where individual D. discoideum cells aggregate together in a food scarce environment.
This class was anticipated by some biologists such as Jahn, who grouped all amoebae with granular pseudopodia together, [1] but most split the lobose amoebae into testate Testacealobosia and naked Gymnamoebia.
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 ...
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 .