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Testate Amoebae
Testate amoebae (formerly thecamoebians, Testacea or Thecamoeba) are a polyphyletic group of unicellular amoeboid protists, which differ from naked amoebae in the presence of a test that partially encloses the cell, with an aperture from which the pseudopodia emerge, that provides the amoeba with shelter from predators and environmental conditions. The test of some species is produced entirely by the amoeba and may be organic, siliceous or calcareous depending on the species (autogenic tests), whereas in other cases the test is made up of particles of sediment collected by the amoeba which are then agglutinated together by secretions from within the cell (xenogenic tests). A few taxa (Hyalosphenidae) can build either type, depending on the circumstances and availability of foreign material. The assemblage referred to as "testate amoebae" is actually composed of several, unrelated groups of organisms. However, some features they all share that have been used to group them together ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Difflugia Acuminata
''Difflugia'' is the largest genus of Arcellinida, one of several groups of Tubulinea within the eukaryote supergroup Amoebozoa. Arcellinida species produce shells or tests from mineral particles or biogeonic elements (e.g. diatom frustules) and are thus commonly referred to as testate amoebae or shelled amoebae. ''Difflugia'' are particularly common in marshes and other freshwater habitats. History The genus ''Difflugia'' was initially discovered in 1815 by L, Leclerc, but its infra-generic classification as a group is still unclear. The genus ''Difflugia'' is the oldest and most diverse of the testate amoebae. It contains more than 300 species and countless subspecies since even minor differences in morphology result in classification as a new species. In 1958, Gauthier-Lièvre and Thomas divided the genus into 10 groups depending on difference in shell morphology. These 10 groups are based on a survey conducted of the African species of ''Difflugia'' The 10 shell shape clas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arcellinida
Arcellinid testate amoebae or Arcellinida,http://www.microscopy-uk.org.uk/mag/artjun03/gsamoebae.html Testate amoebae, peat bogs and past climates. accessed 16 march 2007 Arcellacean or lobose testate amoebae are single-celled protists partially enclosed in a simple test (shell). Arcellinid testate amoebae are commonly found in soils, leaf litter, peat bogs and near/in fresh water. They use their pseudopodia, a temporary cell extension, for moving and taking in food. Like most amoebae, they are generally believed to reproduce asexually via binary fission. However a recent review suggests that sexual recombination may be the rule rather than the exception in amoeboid protists in general, including the Arcellinid testate amoebae. Test or shell Simple tests are made by secretion (autogenous tests), agglutination of foreign material (xenogenous tests), or sometimes a combination of both. Past environmental changes can be determined by analysing the composition of fossil tests, includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euglypha
''Euglypha'' is a genus of cercozoa Cercozoa is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead defined by molecular phylogenies of rRNA and actin or polyubiquitin. They were the first major euk .... It includes the species ''Euglypha rotunda''. References External links * * Cercozoa genera Imbricatea {{Cercozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heleopera
''Heleopera'' is a genus of Amoebozoa Amoebozoa 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 and currently no longer supported c .... It includes the following species. * ''Heleopera sphagni'' * ''Heleopera rosea'' * ''Heleopera sylvatica'' * ''Heleopera petricola'' References External links Amoebozoa genera Taxa named by Joseph Leidy {{Amoebozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Difflugia
''Difflugia'' is the largest genus of Arcellinida, one of several groups of Tubulinea within the eukaryote supergroup Amoebozoa. Arcellinida species produce shells or tests from mineral particles or biogeonic elements (e.g. diatom frustules) and are thus commonly referred to as testate amoebae or shelled amoebae. ''Difflugia'' are particularly common in marshes and other freshwater habitats. History The genus ''Difflugia'' was initially discovered in 1815 by L, Leclerc, but its infra-generic classification as a group is still unclear. The genus ''Difflugia'' is the oldest and most diverse of the testate amoebae. It contains more than 300 species and countless subspecies since even minor differences in morphology result in classification as a new species. In 1958, Gauthier-Lièvre and Thomas divided the genus into 10 groups depending on difference in shell morphology. These 10 groups are based on a survey conducted of the African species of ''Difflugia'' The 10 shell shape class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centropyxis
''Centropyxis'' is a genus of lobose testate amoebae (Amoebozoa Amoebozoa 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 and currently no longer supported c ...), including the species ''Centropyxis aculeata''. References External links Descriptions and pictures of Centropyxis' at Microworld Amoebozoa genera Taxa named by Johann Philip Emil Friedrich Stein {{Amoebozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diplochlamys (protist)
Arcellinid testate amoebae or Arcellinida,http://www.microscopy-uk.org.uk/mag/artjun03/gsamoebae.html Testate amoebae, peat bogs and past climates. accessed 16 march 2007 Arcellacean or lobose testate amoebae are single-celled protists partially enclosed in a simple test (shell). Arcellinid testate amoebae are commonly found in soils, leaf litter, peat bogs and near/in fresh water. They use their pseudopodia, a temporary cell extension, for moving and taking in food. Like most amoebae, they are generally believed to reproduce asexually via binary fission. However a recent review suggests that sexual recombination may be the rule rather than the exception in amoeboid protists in general, including the Arcellinid testate amoebae. Test or shell Simple tests are made by secretion (autogenous tests), agglutination of foreign material (xenogenous tests), or sometimes a combination of both. Past environmental changes can be determined by analysing the composition of fossil tests, includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptodifflugia
''Cryptodifflugia'' is a genus of arcellinid testate amoebae. It contains all the species previously grouped as the genus ''Difflugiella'', which is now a synonym of ''Cryptodifflugia''. Description ''Cryptodifflugia'' species are characterized by a shell with an oval egg-like shape with a short neck. Their surface is either smooth or adhering foreign particles. The shell can be colorless, yellow or brown, composed of an outer proteinaceous material that is usually lined. The shell's aperture is terminal, and has either a circular or an oval shape. They present pseudopods in the form of ectoplasmic anastomosing reticulopods, i.e. like fine threads that can branch or anastomose (meaning they can form links with each other) to create a dense network. Classification The classification of the genus, as revised in 2017, identifies 23 species along with some subspecies: *'' Cryptodifflugia angulata'' Playfair, 1917 – Australia *'' Cryptodifflugia angusta'' (Schönborn, 1965) Page, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apodera
''Apodera'' is a genus of Amoebozoa Amoebozoa 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 and currently no longer supported classi .... References Amoebozoa genera Tubulinea {{Amoebozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SAR Supergroup
The SAR supergroup, also just SAR or Harosa, is a clade that includes stramenopiles ( heterokonts), alveolates, and Rhizaria. The name is an acronym derived from the first letters of each of these clades; it has been alternatively spelled "RAS". The term "Harosa" (at the subkingdom level) has also been used. The SAR supergroup is a node-based taxon. Note that as a formal taxon, "Sar" has only its first letter capitalized, while the earlier abbreviation, SAR, retains all uppercase letters. Both names refer to the same group of organisms, unless further taxonomic revisions deem otherwise. Members of the SAR supergroup were once included under the separate supergroups Chromalveolata ( Chromista and Alveolata) and Rhizaria, until phylogenetic studies confirmed that stramenopiles and alveolates diverged with Rhizaria. This apparently excluded haptophytes and cryptomonads, leading Okamoto ''et al.'' (2009) to propose the clade Hacrobia to accommodate them. Phylogeny Based on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euglyphida
The euglyphids are a prominent group of filose amoebae that produce shells or tests from siliceous scales, plates, and sometimes spines. These elements are created within the cell and then assembled on its surface in a more or less regular arrangement, giving the test a textured appearance. There is a single opening for the long slender pseudopods, which capture food and pull the cell across the substrate. Euglyphids are common in soils, marshes, and other organic-rich environments, feeding on tiny organisms such as bacteria. The test is generally 30-100 μm in length, although the cell only occupies part of this space. During reproduction a second shell is formed opposite the opening, so both daughter cells remain protected. Different genera and species are distinguished primarily by the form of the test. '' Euglypha'' and ''Trinema'' are the most common. The euglyphids are traditionally grouped with other amoebae. However, genetic studies instead place them with var ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filopodia
Filopodia (singular filopodium) are slender cytoplasmic projections that extend beyond the leading edge of lamellipodia in migrating cells. Within the lamellipodium, actin ribs are known as ''microspikes'', and when they extend beyond the lamellipodia, they're known as filopodia. They contain microfilaments (also called actin filaments) cross-linked into bundles by actin-bundling proteins, such as fascin and fimbrin. Filopodia form focal adhesions with the substratum, linking them to the cell surface. Many types of migrating cells display filopodia, which are thought to be involved in both sensation of chemotropic cues, and resulting changes in directed locomotion. Activation of the Rho family of GTPases, particularly cdc42 and their downstream intermediates, results in the polymerization of actin fibers by Ena/Vasp homology proteins. Growth factors bind to receptor tyrosine kinases resulting in the polymerization of actin filaments, which, when cross-linked, make up the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
