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Percolozoa
The Percolozoa are a group of colourless, non-photosynthetic Excavata, including many that can transform between amoeboid, flagellate, and cyst stages. Characteristics Most Percolozoa are found as bacterivores in soil, fresh water and occasionally in the ocean. The only member of this group that is infectious to humans is '' Naegleria fowleri'', the causative agent of the often fatal disease amoebic meningitis. The group is closely related to the Euglenozoa, and share with them the unusual characteristic of having mitochondria with discoid cristae. The presence of a ventral feeding groove in the flagellate stage, as well as other features, suggests that they are part of the Excavata group. The amoeboid stage is roughly cylindrical, typically around 20-40 μm in length. They are traditionally considered lobose amoebae, but are not related to the others, and unlike them, do not form true lobose pseudopods. Instead, they advance by eruptive waves, where hemispherical bulges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naegleria Fowleri
''Naegleria fowleri'', colloquially known as a "brain-eating amoeba", is a species of the genus '' Naegleria'', belonging to the phylum Percolozoa, which is technically not classified as true amoeba, but a shapeshifting amoeboflagellate excavate. It is a free-living, bacteria-eating microorganism that can be pathogenic, causing an extremely rare, sudden, severe and usually fatal brain infection called naegleriasis or primary amoebic meningoencephalitis (PAM). This microorganism is typically found in bodies of warm freshwater, such as ponds, lakes, rivers, hot springs, warm water discharge from industrial or power plants, geothermal well water, poorly maintained or minimally chlorinated (under 0.5 mg/m3 residual) swimming pools, water heaters, soil, and pipes connected to tap water. It can be seen in either an amoeboid or temporary flagellate stage. Etymology The organism was named after Malcolm Fowler, an Australian pathologist at Adelaide Children's Hospital, who was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1 E-5 M
1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1. In conventions of sign where zero is considered neither positive nor negative, 1 is the first and smallest positive integer. It is also sometimes considered the first of the infinite sequence of natural numbers, followed by 2, although by other definitions 1 is the second natural number, following 0. The fundamental mathematical property of 1 is to be a multiplicative identity, meaning that any number multiplied by 1 equals the same number. Most if not all properties of 1 can be deduced from this. In advanced mathematics, a multiplicative identity is often denoted 1, even if it is not a number. 1 is by convention not considered a prime number; this was not universally accepted until the mid-20th century. Additionally, 1 is the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sporangium
A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cycle. Sporangia can produce spores by mitosis, but in nearly all land plants and many fungi, sporangia are the site of meiosis and produce genetically distinct haploid spores. Fungi In some phyla of fungi, the sporangium plays a role in asexual reproduction, and may play an indirect role in sexual reproduction. The sporangium forms on the sporangiophore and contains haploid nuclei and cytoplasm. Spores are formed in the sporangiophore by encasing each haploid nucleus and cytoplasm in a tough outer membrane. During asexual reproduction, these spores are dispersed via wind and germinate into haploid hyphae. Although sexual reproduction in fungi varies between phyla, for some fungi the sporangium plays an indirect role in sexual re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dictyostelid
The dictyostelids (Dictyostelia/Dictyostelea, ICZN, or Dictyosteliomycetes, ICBN) are a group of cellular slime molds, or social amoebae. Multicellular behavior When food (normally bacteria) is readily available dictyostelids behave as individual amoebae, which feed and divide normally. However, when the food supply is exhausted, they aggregate to form a multicellular assembly, called a pseudoplasmodium, grex, or slug (not to be confused with the gastropod mollusc called a slug). The grex has a definite anterior and posterior, responds to light and temperature gradients, and has the ability to migrate. Under the correct circumstances the grex matures forming a sorocarp (fruiting body) with a stalk supporting one or more sori (balls of spores). These spores are inactive cells protected by resistant cell walls, and become new amoebae once food is available. In ''Acytostelium'', the sorocarp is supported by a stalk composed of cellulose, but in other dictyostelids the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrasid
The family Acrasidae (ICZN, or Acrasiomycota, ICBN) is a family of slime molds which belongs to the excavate group Percolozoa. The name element - comes from the Greek ''akrasia'', meaning "acting against one's judgement". This group consists of cellular slime molds. Some would also consider it as a kingdom unto itself, but the debate is as yet unsettled. The terms "Acrasiomycota" or "Acrasiomycetes" have been used when the group was classified as a fungus ("-mycota"). In some classifications, '' Dictyostelium'' was placed in Acrasiomycetes, an artificial group of cellular slime molds, which was characterized by the aggregation of individual amoebae into a multicellular fruiting body, making it an important factor that related the acrasids to the dictyostelids. Reproduction When resources such as water or food become limiting, the amoeba will release pheromones such as acrasin to aggregate amoebal cells in preparation for movement as a large (thousands of cells) grex or p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudovahlkampfia
''Pseudovahlkampfia'' is a genus of Excavates Excavation may refer to: * Excavation (archaeology) * Excavation (medicine) * ''Excavation'' (The Haxan Cloak album), 2013 * ''Excavation'' (Ben Monder album), 2000 * ''Excavation'' (novel), a 2000 novel by James Rollins * '' Excavation: A Memo ... It includes the species ''Pseudovahlkampfia emersoni''. References Percolozoa Excavata genera {{Excavata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vahlkampfia
''Vahlkampfia'' is a genus of amoeboid An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopo ...s in Heterolobosea. References Further reading *Brown, Susan; De Jonckheere, Johan F. (Feb. 25, 1999). "A reevaluation of the amoeba genus Vahlkampfia based on SSUrDNA sequences". ''European Journal of Protistology'' 35 (1):49-54. doi:10.1016/S0932-4739(99)80021-2 * * Percolozoa Excavata genera {{Excavata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psalteriomonas
''Psalteriomonas'' is a genus of excavates Excavation may refer to: * Excavation (archaeology) * Excavation (medicine) * ''Excavation'' (The Haxan Cloak album), 2013 * ''Excavation'' (Ben Monder album), 2000 * ''Excavation'' (novel), a 2000 novel by James Rollins * '' Excavation: A Memo ... in the group of Heterolobosea. The genus was first discovered and named in 1990. It contains amoeboflagellate cells that live in freshwater anaerobic sediments all over the world. The microtubule-organizing ribbon and the associated microfibrillar bundles of the mastigote system is the predominant feature in Psalteriomonas. This harp-shaped complex gives rise to the name of this genus. ''Psalteriomonas''forms an endosymbiotic relationship with methanogenic bacteria, especially with ''Methanobacterium formicicum'' There are currently three species in this genus: ''P. lanterna'', ''P. vulgaris'', and ''P. magna''. Etymology The name of the genus ''Psalteriomonas'' comes from the word ''psa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
