| Raphidiophrys contractilis | |
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| Raphidiophrys contractilis | |
| Scientific classification | |
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| Genus: | |
| Species: | R. contractilis |
| Binomial name | |
| Raphidiophrys contractilis | |
Raphidiophrys contractilis is a species of freshwater centrohelid.
| Raphidiophrys contractilis | |
|---|---|
| | |
| Raphidiophrys contractilis | |
| Scientific classification | |
| Domain: | |
| Order: | |
| Family: | |
| Genus: | |
| Species: | R. contractilis |
| Binomial name | |
| Raphidiophrys contractilis | |
Raphidiophrys contractilis is a species of freshwater centrohelid.
This species was first isolated from a brackish pond in Shukkeien Garden, Naka-ku, Hiroshima City, Japan. [1]
Raphidiophrys contractilis is a spherical organism measuring between 7 and 19 µm in diameter and has several axopodia measuring between 60 and 110 µm. The axopodia are sustained by a set of microtubules arranged in a complex of hexagons and triangles. [1] The cell body is coated by a thin layer of small scales composed of silica. These scales are oblong, with curved edges and with the surface always facing the cell body. [1]
Raphidiophrys contractilis preys on other protists, such as flagellates and ciliates, and captures them with its axopodia. The axopodia contain many organelles called kinetocysts, which are released on the prey's surface and probably have a paralyzing effect. [2] After the prey is attached to the axopodium, the axopodium contracts rapidly, at a velocity of about 1 mm/s, this being the reason for the species being named Raphidiophrys contractilis. [1]
Although R. contractilis is not a colonial species, several individuals can cooperate in the capture of larger prey. In this case, the individuals gather around the prey and fuse into a larger structure with partially joined cytoplasms and build a common food vacuole to ingest and digest the prey organism. [2]
The actinophryids are an order of heliozoa, a polyphyletic array of stramenopiles, having a close relationship with pedinellids and Ciliophrys. They are common in fresh water and occasionally found in marine and soil habitats. Actinophryids are unicellular and roughly spherical in shape, with many axopodia that radiate outward from the cell body. Axopodia are a type of pseudopodia that are supported by hundreds of microtubules arranged in interlocking spirals and forming a needle-like internal structure or axoneme. Small granules, extrusomes, that lie under the membrane of the body and axopodia capture flagellates, ciliates and small metazoa that make contact with the arms.
Zooplankton are the animal component of the planktonic community. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequently, they drift or are carried along by currents in the ocean, or by currents in seas, lakes or rivers.
The centrohelids or centroheliozoa are a large group of heliozoan protists. They include both mobile and sessile forms, found in freshwater and marine environments, especially at some depth.
Blepharisma is a genus of unicellular ciliate protists found in fresh and salt water. The group includes about 40 accepted species, and many sub-varieties and strains. While species vary considerably in size and shape, most are easily identified by their red or pinkish color, which is caused by granules of the pigment blepharismin.
Carpediemonas is genus of Metamonada, and belongs to the group Excavata. This organism is a unicellular flagellated eukaryote that was first discovered in substrate samples from the Great Barrier Reef. Carpediemonas can be found in anaerobic intertidal sediment, where it feeds on bacteria. A feature of this species is the presence of a feeding groove, a characteristic of the excavates. Like most other metamonads, Carpediemonas does not rely on an aerobic mitochondrion to produce energy. Instead, it contains hydrogenosomes that are used to produce ATP. This organism has two flagella: a posterior one used for feeding on the substrate, and an anterior one that moves in a slower sweeping motion. Carpediemonas is assigned to the fornicates, where similar Carpediemonas-like organisms are used in researching the evolution within excavates. Although Carpediemonas is a member of the metamonads, it is unusual in the sense that it is free-living and has three basal bodies.
Malawimonas is genus of unicellular, heterotrophic flagellates with uncertain phylogenetic affinities. They have variably being assigned to Excavata and Loukozoa. Recent studies suggest they may be closely related to the Podiata.
The genus Labyrinthula is part of the protist group Labyrinthulomycetes and contains thirteen species. The major feature of this genus is the formation of an ectoplasmic net secreted by specialized organelles called bothrosomes which surrounds the colony, which is also used by Labyrinthula for moving. The protist reproduces by zoosporulation as it sets some flagellated spores free from a sporangium. One of the flagella of the zoospores has stiff tripartite hairs (mastigonemes) - the defining characteristic of the stramenopiles.
Proteromonas is a genus of single-celled biflagellated microbial eukaryotes belonging to the Superphylum Stramenopiles which are characterized by the presence of tripartite, hair-like structures on the anteriorly-directed larger of the two flagella. Proteromonas on the other hand are notable by having tripartite hairs called somatonemes not on the flagella but on the posterior of the cell. Proteromonas are closely related to Karotomorpha and Blastocystis, which belong to the Opalines group.
Willaertia /ˈwɪləɹʃə/ is a genus of non-pathogenic, free-living, thermophilic amoebae in the family Vahlkampfiidae.
Raphidiophrys is a genus of centrohelid with radiating axopodia. R. intermedia is found in the bottom sludge of freshwater bodies in Canada, Chile, Argentina, Australia, New Zealand, Malaysia, Russia, and central Europe. Raphidiophrys have bipartite scales are a defining characteristic among species. Differences in type and size of scales are used to differentiate amongst the members of this genus. The genus Raphidiophrys was discovered in 1867 by W. Archer. Raphidiophrys is one of very few centrohelids in which dimorphism has been shown.
Oxyrrhis is a genus of heterotrophic dinoflagellate, the only genus in the family Oxyrrhinaceae. It inhabits a range of marine environments worldwide and is important in the food web dynamics of these ecosystems. It has the potential to be considered a model organism for the study of other protists. Oxyrrhis is an early-branching lineage and has long been described in literature as a monospecific genus, containing only Oxyrrhis marina. Some recent molecular phylogenetic studies argue that Oxyrrhis comprises O. marina and O. maritima as distinct species, while other publications state that the two are genetically diverse lineages of the same species. The genus has previously been suggested to contain O. parasitica as a separate species, however the current consensus appears to exclude this, with Oxyrrhis being monospecific and containing O. marina and O. maritima as separate lineages of the type species. The genus is characterised by its elongated body which is anteriorly prolonged to a point, its complex flagellar apparatuses which attach to the ventral side of the cell, and the unique features of its nucleus.
Thaumatomastix is a protist genus of the order Thaumatomonadida, within the phylum Cercozoa and the class Imbricatea. Its species are aquatic, feeding on algae and appearing in waters of a wide range of temperatures and salinities, and are 15-50 micrometers long. They can interchange between flagellated and amoeboid forms, and are notable for being covered in both spiny and flattened siliceous scales.
Reticulomyxa is a monospecific genus of freshwater foraminiferans. The type species is the unicellular Reticulomyxa filosa. It is found in freshwater environments as well as moist environments, like decomposing matter and damp soils. The heterotrophic naked foraminiferan can feed on microbes as well has larger organisms and is able to be sustained in culture by supplemented nutrients such as wheat germ and oats. The large, multinucleate foraminferan is characteristic for its lack of test and named for the network of connecting pseudopodia surrounding its central body mass. The organism has unique bidirectional cytoplasmic streaming throughout the anastomosing pseudopodia that is some of the fastest reported organelle transport observed. Reticulomyxa was first described in 1949 and is commonly used as a model organism for the unique transport of organelles throughout the cytoplasm of pseudopodia by cytoskeletal mechanisms. Only asexual reproduction of this genus has been observed in culture, but the genome possesses genes related to meiosis suggesting it is capable of sexually reproductive life stages.
Kraken is a genus of amoebae within the Cercozoa, containing the sole species Kraken carinae. These amoebae are characterized by a small round cell body and a network of thin and very long filopodia that can reach up to a mm in diameter. Kraken amoebae feed on bacteria and live in freshwater and soil systems.
Tsukubamonas is a monotypic genus of excavates that contains a single species, Tsukubamonas globosaYabuki et al. 2011. T. globosa is a free-living flagellate that was isolated from a pond in the University of Tsukuba, Japan.
Raphidiophrys drakena is a species of protist in the genus of Raphidiophrys. It is a unicellular eukaryote with a cell diameter of 26.7±0.39 μm and several cell surface features like axopodia, kinecysts and a tangential scale layer. The scales have a length of 6.0±0.18 μm and a width of 3.5±0.14 μm. R. drakena differs from other morphologically studied members of the genus Rhaphidiophrys by lacking spicules on its surface.
Ceratocorys is a genus of photosynthetic free-living marine dinoflagellates first described in 1883 by Friedrich Stein. Currently consisting of 12 species, this genus is typically found at the water surface in tropical and subtropical ocean regions, and has both low nutrient requirements and salinity sensitivity. All species in the genus have a theca; 29 membrane-bound armored plates with anywhere from 2 to 6 spines protruding from the cell. They reproduce through binary fission at temperatures above 20°C during asexual reproduction and whether or not they have sexual reproduction is not known. Due to its bioluminescent capabilities, the type species of this genus, Ceratocorys horrida, has many practical applications. Its bioluminescent response to water flow means it can act as a model organism for understanding planktonic reaction to water movement. It is also sensitive to environmental molecules; by measuring the bioluminescent response it can be used in rapid toxicity tests to detect the levels of different contaminants in water systems. Its presence is also an indicator of different oceanic phenomena like upwellings or tropical waters.
Vampyrella is a genus of amoebae belonging to the vampyrellid cercozoans usually ranging from 30-60 µm. Members of the genus alternate between two life stages: a free-living trophozoite stage and a cyst stage in which mitosis occurs. This taxon has received a great deal of attention due to their peculiar feeding behaviour of perforating the cell wall of algal cells and drawing out the contents for nourishment.
Vampyrella lateritia is a freshwater species of predatory amoebae that feeds on species of algae and is known for its specialized feeding strategy of removing, digesting, and ingesting the cellular contents of its prey. It is the type species of the genus Vampyrella and has been identified in numerous locations around the world including Brazil, Germany, and the eastern United States. Along with Vampyrella pendula, its genome was sequenced in 2012.
Synchroma is a genus of marine stramenopile algae containing two species with amoeboid morphology. They are grouped within the monotypic family Synchromaceae and order Synchromales as part of an independent clade of ochrophytes known as Picophagea or Synchromophyceae.
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