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Ciliate
The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagellum, eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different wikt:undulating, undulating pattern than flagella. Cilia occur in all members of the group (although the peculiar Suctoria only have them for part of their biological life cycle, life cycle) and are variously used in swimming, crawling, attachment, feeding, and sensation. Ciliates are an important group of protists, common almost anywhere there is water—in lakes, ponds, oceans, rivers, and soils. About 4,500 unique free-living species have been described, and the potential number of extant species is estimated at 27,000–40,000. Included in this number are many Ectosymbiosis, ectosymbiotic and endosymbiotic species, as well as some Obligate parasite, obligate and Facultative parasite, opportunistic parasites. Ciliate species r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paramecium
'' ''Paramecium'' ( , ; also spelled ''Paramoecium'') is a genus of eukaryotic, unicellular ciliates, commonly studied as a representative of the ciliate group. ''Paramecia'' are widespread in freshwater, brackish, and marine environments and are often very abundant in stagnant basins and ponds. Because some species are readily cultivated and easily induced to conjugate and divide, it has been widely used in classrooms and laboratories to study biological processes. Its usefulness as a model organism has caused one ciliate researcher to characterize it as the " white rat" of the phylum Ciliophora. Historical background ''Paramecia'' were among the first ciliates to be seen by microscopists, in the late 17th century. They were probably known to the Dutch pioneer of protozoology, Antonie van Leeuwenhoek, and were clearly described by his contemporary Christiaan Huygens in a letter of 1678. The earliest known illustration of a Paramecium was published anonymously in Philosophi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karyorelictea
Karyorelictea is a class of ciliates in the subphylum Postciliodesmatophora. Most species are members of the microbenthos community, that is, microscopic organisms found in the marine interstitial habitat, though one genus, ''Loxodes'', is found in freshwater. The majority of karyorelict taxa have not been cultivated in the laboratory, although clonal lines of ''Loxodes'' have been developed. Systematics According to Lynn (2008), the Karyorelictea class is divided into three orders: * Loxodida, containing the families Cryptopharyngidae and Loxodidae; * Protoheterotrichida, containing the families Aveliidae and Geleiidae; * Protostomatida, containing the families Kentrophoridae and Trachelocercidae. These three orders were defined morphologically, and have been confirmed with molecular phylogenetics. An additional family, Wilbertomorphidae, is of uncertain affiliation and has not been assigned to an order. Nuclear dimorphism All ciliates, including karyorelicteans, p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alveolate
The alveolates (meaning "pitted like a honeycomb") are a group of protists, considered a major clade and Biological classification, superphylum within Eukarya. They are currently grouped with the stramenopiles and Rhizaria among the protists with tubulocristate mitochondria, the group being referred to as SAR supergroup, SAR. Characteristics The most notable shared characteristic is the presence of cortical (near the surface) alveoli (sacs). These are flattened vesicle (biology), vesicles (sacs) arranged as a layer just under the cell membrane, membrane and supporting it, typically contributing to a flexible pellicle (thin skin). In armored dinoflagellates they may contain stiff plates. Alveolates have mitochondrion, mitochondria with tubular cristae (invaginations), and cells often have pore-like intrusions through the cell surface. The group contains free-living and parasitic organisms, predatory flagellates, and photosynthetic organisms. Almost all sequenced mitochondrial g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armophorea
Armophorea is a class of ciliates in the subphylum Intramacronucleata. . It was first resolved in 2004 and comprises three orders: Metopida, Clevelandellida, and Armophorida. Previously members of this class were thought to be heterotrichs because of similarities in morphology, most notably a characteristic dense arrangement of cilia surrounding their oral structures. However, the development of genetic tools and subsequent incorporation of DNA sequence information has led to major revisions in the evolutionary relationships of many protists, including ciliates. Metopids, clevelandellids, and armophorids were grouped into this class based on similarities in their small subunit rRNA sequences, making them one of two so-called "riboclasses" of ciliates, however, recent analyses suggest that Armophorida may not be related to the other two orders. Etymology The name Armophorea is thought to be derived from the Latin word ''arma,'' meaning weapons, or ''armus'', meaning shoulder. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colpodea
The Colpodea are a class of ciliates, of about 200 species common in freshwater and soil habitats. The body cilia are typically uniform, and are supported by dikinetids of characteristic structure, with cilia on both kinetosomes. The mouth may be apical or ventral, with more or less prominent associated polykinetids. Many are asymmetrical, the cells twisting sideways and then untwisting again prior to division, which often takes place within cysts. ''Colpoda'', a kidney-shaped ciliate common in organic rich conditions, is representative. Most ciliates placed here were originally considered advanced trichostomes, on the assumption that they lacked true oral cilia. However the Bursariomorphida, large carnivorous ciliates whose oral cavity forms a deep anterior pocket, were considered heterotrichs because of their prominent oral polykinetids. The modern class was first defined by Small Small may refer to: Science and technology * SMALL, an ALGOL-like programming language ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cilia
The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projection that extends from the surface of the much larger cell body. Eukaryotic flagella found on sperm cells and many protozoans have a similar structure to motile cilia that enables swimming through liquids; they are longer than cilia and have a different undulating motion. There are two major classes of cilia: ''motile'' and ''non-motile'' cilia, each with a subtype, giving four types in all. A cell will typically have one primary cilium or many motile cilia. The structure of the cilium core called the axoneme determines the cilium class. Most motile cilia have a central pair of single microtubules surrounded by nine pairs of double microtubules called a 9+2 axoneme. Most non-motile cilia have a 9+0 axoneme that lacks the central pair of mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterotrich
The heterotrichs are a class of ciliates. They typically have a prominent adoral zone of membranelles circling the mouth, used in locomotion and feeding, and shorter cilia on the rest of the body. Many species are highly contractile, and are typically compressed or conical in form. These include some of the largest protozoa, such as ''Stentor'' and ''Spirostomum'', as well as many brightly pigmented forms, such as certain ''Blepharisma''. Etymology The term ''heterotrich'' derives from the ancient Greek (), meaning "another, different", and , (), meaning 'hair', because of the contrast between the regular somatic ciliation and the one of the oral zone. Ultrastructure A number of ultrastructural details characterize the group. The cilia on the body are in dikinetids, in which either the anterior one or both kinetosomes may be ciliated, and which are associated with fibers composed of overlapping postciliary microtubules, called ''postciliodesmata'' and found only in this g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protist
A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the exclusion of other eukaryotes means that protists do not form a natural group, or clade. Therefore, some protists may be more closely related to animals, plants, or fungi than they are to other protists. However, like the groups ''algae'', ''invertebrates'', and '' protozoans'', the biological category ''protist'' is used for convenience. Others classify any unicellular eukaryotic microorganism as a protist. The study of protists is termed protistology. History The classification of a third kingdom separate from animals and plants was first proposed by John Hogg in 1860 as the kingdom Protoctista; in 1866 Ernst Haeckel also proposed a third kingdom Protista as "the kingdom of primitive forms". Originally these also included prokaryotes, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coleps
''Coleps'' is a genus of ciliates in the class Prostomatea with barrel-shaped bodies surrounded by regularly arranged plates composed of calcium carbonate. Description Species of ''Coleps'' can grow up to 250 µm in length, but are usually under 100 µm in their longest axis. ''Coleps'' can be taxonomically distinguished by the ornamentation of the ectoplasmic plates which make up their test. These plates are located outside alveolar vesicles of the cell cortex, and contain both organic and inorganic components, the latter of which is mostly amorphous calcium carbonate. Predatory behavior ''Coleps'' feeds on bacteria, algae, flagellate A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their ...s, living and dead ciliates, animal and plant tissues. ''Coleps'' uses toxicysts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plagiopylid
The plagiopylids are a small order of ciliates, including a few forms common in anaerobic habitats. The body cilia are dense, and arise from monokinetids with an entirely unique ultrastructure; one or two rows of dikinetids run into the oral cavity, which takes the form of a groove, with a deep tube lined by oral cilia leading to the mouth. The order was introduced by Eugen Small and Denis Lynn in 1985, who treated it as a subclass of Oligohymenophorea. Since then they tend to be treated as an independent class, possibly affiliated with the Colpodea. Class Plagiopylea is divided into two clades: one contains members of the order Plagiopylida (like ''Plagiopyla frontata'' and ''Trimyema compressum'') and the second clade contains plagiopylean ciliate associated with Denitrification, denitrifying obligate endosymbiont Azoamicus ciliaticola, ''Candidatus'' Azoamicus ciliaticola. References Further reading * * Intramacronucleata Ciliate orders {{Ciliate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Litostomatea
The Litostomatea are a class of ciliates. The group consists of three subclasses: Haptoria, Trichostomatia and Rhynchostomatia. Haptoria includes mostly carnivorous forms such as ''Didinium'', a species of which preys primarily on the ciliate ''Paramecium''. Trichostomatia (trichostomes) are mostly endosymbionts in the digestive tracts of vertebrates. These include the species ''Balantidium coli'', which is the only ciliate parasitic in humans. The group Rhynchostomatia includes two free-living orders previously included among the Haptoria, but now known to be genetically distinct from them, the Dileptida and the Tracheliida. Morphology In litostomes, the body cilia arise from structures in the cell cortex called monokinetids, which are made up of a single cilium and its associated structures, such as basal bodies and microtubular fibres. These have an ultrastructural arrangement characteristic to the group. The cell "mouth" (cytostome) is apical or subapical. In trichostomes it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parablepharismea
Parablepharismea is a class of free-living marine and brackish anaerobic ciliates that form a major clade of obligate anaerobes within the SAL group ( Spirotrichea, Armophorea, and Litostomatea), together with the classes Muranotrichea and Armophorea Armophorea is a class of ciliates in the subphylum Intramacronucleata. . It was first resolved in 2004 and comprises three orders: Metopida, Clevelandellida, and Armophorida. Previously members of this class were thought to be heterotrichs beca .... Parablepharismea are medium to large, elongated ciliates with navicular outline and holotrichous somatic ciliature composed of dikinetids without postciliodesmata. Their oral ciliature is composed of bipartite paroral membrane and adoral zone of membranelles. They host a thick coat of prokaryotic ectosymbionts and cytoplasmic endosymbionts. They are found in micro-oxic marine to brackish habitats. Parablepharismea may be related to the deep sea Cariacotrichea ciliates. This class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
