26-461: (Redirected from Myxomycetes ) Myxomycota and Myxomycetes are terms used to refer to some fungus-like amoebozoa : Infraphylum Mycetozoa (which encompasses Myxogastria among other classes) Class Myxogastria alone See also [ edit ] Wikispecies:Fungi (classifications) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with
52-410: A "monopodial" form, with the entire cell functioning as a single pseudopod. Large pseudopods may produce numerous clear projections called subpseudopodia (or determinate pseudopodia ), which are extended to a certain length and then retracted, either for the purpose of locomotion or food intake. A cell may also form multiple indeterminate pseudopodia, through which the entire contents of the cell flow in
78-454: A crucial role in regulating actin polymerization and organization, localizing in the cortical actin network, discrete adhesion foci, and the perinuclear region. However, actin polymerization at the leading edge of migrating pseudopodia occurs independently of the Arp2/3 complex. During migration, changes in the ratio of filamentous actin (F-actin) to total actin correlate with the contractile state of
104-512: A high-level taxon , named Amorphea . 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. Some live as parasites or symbionts of other organisms, and some are known to cause disease in humans and other organisms. While
130-509: A more suitable name for a clade of approximately the same composition, a sister group to the Diaphoretickes . More recent work places the members of Amorphea together with the malawimonids and collodictyonids in a proposed clade called Opimoda, which comprises one of two major lineages diverging at the root of the eukaryote tree of life, the other being Diphoda . Traditionally all amoebozoa with lobose pseudopods were grouped together in
156-400: A posterior bulb called a uroid, which may serve to accumulate waste, periodically detaching from the rest of the cell. When food is scarce, most species can form cysts , which may be carried aerially and introduce them to new environments. In slime moulds, these structures are called spores, and form on stalked structures called fruiting bodies or sporangia . Mixotrophic species living in
182-531: A symbiotic relationship with microalgae of the genus Chlorella , which lives inside the cytoplasm of their host, have been found in Arcellinida and Mayorella . The majority of Amoebozoa lack flagella and more generally do not form microtubule -supported structures except during mitosis . However, flagella do occur among the Archamoebae , and many slime moulds produce biflagellate gametes . The flagellum
208-635: A thick-walled nucleus containing granular chromatin , and is therefore a eukaryote . Its membrane consists of a phospholipid bilayer similar to other eukaryotic organisms. The first description of this amoeba is probably that of August Johann Rösel von Rosenhof who, in 1755, published drawings of an amoeboid protozoan he called the "little Proteus". Subsequently, various authors assigned Rösel's organism and other amoeboid protozoa various names: Carl Linnaeus termed Rösel's organism Chaos protheus in 1758. Otto Friedrich Müller referred to it as Proteus diffluens in 1786. In 1878, Joseph Leidy proposed
234-423: 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. During locomotion, the endoplasm flows forwards and the ectoplasm runs backwards along the outside of the cell. In motion, many amoebozoans have a clearly defined anterior and posterior and may assume
260-646: 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 . This protozoan uses extensions called pseudopodia to move and to eat smaller unicellular organisms . Food is enveloped inside the cell's cytoplasm in a food vacuole , where ingested matter is slowly broken down by enzymes. A. proteus inhabits freshwater environments and feeds on protozoans, algae, rotifers, and even other smaller amoebae. They are colorless, but they may have colored inclusions derived from their food. A. proteus possesses
286-491: Is a major taxonomic group containing about 2,400 described species of amoeboid protists , often possessing blunt, fingerlike, lobose pseudopods and tubular mitochondrial cristae . In traditional classification schemes, Amoebozoa is usually ranked as a phylum within either the kingdom Protista or the kingdom Protozoa . In the classification favored by the International Society of Protistologists, it
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#1732876981002312-486: Is generally anchored by a cone of microtubules, suggesting a close relationship to the opisthokonts . The mitochondria in amoebozoan cells characteristically have branching tubular cristae. However, among the Archamoebae , which are adapted to anoxic or microaerophilic habitats, mitochondria have been lost. It appears (based on molecular genetics) that the members of Amoebozoa form a sister group to animals and fungi, diverging from this lineage after it had split from
338-502: Is retained as an unranked " supergroup " within Eukaryota. Molecular genetic analysis supports Amoebozoa as a monophyletic clade . Modern studies of eukaryotic phylogenetic trees identify it as the sister group to Opisthokonta , another major clade which contains both fungi and animals as well as several other clades comprising some 300 species of unicellular eukaryotes. Amoebozoa and Opisthokonta are sometimes grouped together in
364-738: The Lobosa are paraphyletic: Conosa is sister of the Cutosea. Centramoebida Himatismenida Himatismenida Thecamoebida Dermamoebida Vannellida Dactylopodida Trichosida Microcoryciidae Echinamoebida Leptomyxida Euamoebida Arcellinida Squamocutida Entamoebida Pelobiontida Phalansteriida Flamellidae Ramamoebida Profiliida Fractovitellida Acytosteliales Dictyosteliida Ceratiomyxida Protosporangiida Cribrariales Reticulariales Liceida Trichiida Amoeba proteus Volvox proteus Pallas, 1766 Amoeba proteus
390-673: The cell cortex, where an increasing F-actin/total actin ratio corresponds to isometric contraction, while a decreasing ratio indicates isotonic contraction associated with cytoskeleton disintegration. Furthermore, the Rac/PAK pathway is involved in regulating cell migration, with the PAK kinase MIHCK acting as an effector for the Rac-like protein, and inhibition of MIHCK disrupts normal migration and pseudopod formation, although it does not directly affect actin polymerization. Although Amoeba proteus has most of
416-502: The class Lobosea , placed with other amoeboids in the phylum Sarcodina or Rhizopoda , but these were considered to be unnatural groups. Structural and genetic studies identified the percolozoans and several archamoebae as independent groups. In phylogenies based on rRNA their representatives were separate from other amoebae, and appeared to diverge near the base of eukaryotic evolution, as did most slime molds. However, revised trees by Cavalier-Smith and Chao in 1996 suggested that
442-475: The classic Lobosea: non-flagellated amoebae with blunt, lobose pseudopods ( Amoeba , Acanthamoeba, Arcella, Difflugia etc. ). The latter is made up of both amoeboid and flagellated cells, characteristically with more pointed or slightly branching subpseudopodia (Archamoebae and the Mycetozoan slime molds). From older studies by Cavalier-Smith, Chao & Lewis 2016 and Silar 2016. Also recent phylogeny indicates
468-528: The current name Amoeba proteus to describe Rösel's Proteus , Proteus diffluens , and another described amoeba Amoeba princeps . The locomotion of Amoeba proteus exhibits chaotic dynamics described by a low-dimensional chaotic attractor with a correlation dimension around 3-4, indicating that the seemingly random movement arises from deterministic cooperative interactions among a small number of processes like sol-gel transformations, cytoplasmic streaming, and calcium-mediated reactions. The Arp2/3 complex plays
494-406: The direction of locomotion. These are more or less tubular and are mostly filled with granular endoplasm. The cell mass flows into a leading pseudopod, and the others ultimately retract, unless the organism changes direction. While most amoebozoans are "naked," like the familiar Amoeba and Chaos , or covered with a loose coat of minute scales, like Cochliopodium and Korotnevella , members of
520-464: The largest protozoa. The well-known species Amoeba proteus , which may reach 800 μm in length, is often studied in schools and laboratories as a representative cell or model organism , partly because of its convenient size. Multinucleate amoebae like Chaos and Pelomyxa may be several millimetres in length, and some multicellular amoebozoa, such as the "dog vomit" slime mold Fuligo septica , can cover an area of several square meters. Amoebozoa
546-424: The majority of amoebozoan species are unicellular, the group also includes several clades of slime molds , which have a macroscopic, multicellular stage of life during which individual amoeboid cells remain together after multiple cell division to form a macroscopic plasmodium or, in cellular slime molds, aggregate to form one. Amoebozoa vary greatly in size. Some are only 10–20 μm in diameter, while others are among
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#1732876981002572-468: The name "unikonts" (formally, Unikonta) for this branch, whose members were believed to have been descended from a common ancestor possessing a single emergent flagellum rooted in one basal body . However, while the close relationship between Amoebozoa and Opisthokonta is robustly supported, recent work has shown that the hypothesis of a uniciliate ancestor is probably false. In their Revised Classification of Eukaryotes (2012), Adl et al. proposed Amorphea as
598-619: The order Arcellinida form rigid shells, or tests , equipped with a single aperture through which the pseudopods emerge. Arcellinid tests may be secreted from organic materials, as in Arcella , or built up from collected particles cemented together, as in Difflugia . In all amoebozoa, the primary mode of nutrition is phagocytosis , in which the cell surrounds potential food particles with its pseudopods, sealing them into vacuoles within which they may be digested and absorbed. Some amoebozoans have
624-404: The other groups, as illustrated below in a simplified diagram: Loukozoa [REDACTED] CRuMs [REDACTED] Amoebozoa Breviata [REDACTED] Apusomonadida [REDACTED] Fungi [REDACTED] Animalia [REDACTED] Strong similarities between Amoebozoa and Opisthokonts lead to the hypothesis that they form a distinct clade. Thomas Cavalier-Smith proposed
650-669: The remaining lobosans do form a monophyletic group, to which the Archamoebae and Mycetozoa were closely related, although the percolozoans were not. Subsequently, they emended the phylum Amoebozoa to include both the subphylum Lobosa and a new subphylum Conosa , comprising the Archamoebae and the Mycetozoa . Recent molecular genetic data appear to support this primary division of the Amoebozoa into Lobosa and Conosa. The former, as defined by Cavalier-Smith and his collaborators, consists largely of
676-459: The title Myxomycota . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Myxomycota&oldid=1176708184 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Amoebozoa Amoebozoa
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