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Oligohymenophorea
The Oligohymenophorea are a large class of ciliates. There is typically a ventral groove containing the mouth and distinct oral cilia, separate from those of the body. These include a paroral membrane to the right of the mouth and membranelles, usually three in number, to its left. The cytopharynx is inconspicuous and never forms the complex cyrtos found in similar classes. Body cilia generally arise from monokinetids, with dikinetids occurring in limited distribution over part of the body. In most groups the body cilia are uniform and often dense, while the oral cilia are inconspicuous and sometimes reduced, but among the peritrichs almost the opposite is the case. Members are widely distributed, and include many free-living (typically fresh-water, but many marine) and symbiotic forms. Most are microphagous, grazing on smaller organisms swept into the mouth by the cilia, but various other feeding habits occur. In one group, the astomes, the mouth and associated struct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciliate
The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different undulating pattern than flagella. Cilia occur in all members of the group (although the peculiar Suctoria only have them for part of their 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 ectosymbiotic and endosymbiotic species, as well as some obligate and opportunistic parasites. Ciliate species range in size from as little as 10 µm in some colpodeans to as much as 4 mm in length in s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scuticociliatia
Scuticociliatia is a subclass of ciliates in the class Oligohymenophorea. Its members are called scuticociliates. These unicellular eukaryotes are marine microorganisms that are usually free-living and widely distributed in the world's oceans. Around 20 members of the group have been identified as causative agents of the disease scuticociliatosis, in which the ciliates are parasites of other marine organisms. Species known to be susceptible include a broad range of teleosts, seahorses, sharks, and some crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...s. References * * External links * Oligohymenophorea [Baidu] |
Peritrich
The peritrichs (Latin: Peritrichia) are a large and distinctive group of ciliates. The peritrichs were first defined by Friedrich von Stein in 1859. Initially they were considered spirotrichs, then treated as a separate category, before receiving their modern placement. Structure They are usually bell or disc shaped, with a prominent paroral membrane arising from the oral cavity and circling counter-clockwise around the anterior of the cell, accompanied by a smaller series of membranelles. The oral cavity is apical and funnel shaped, with a contractile vacuole discharging directly into it. When disturbed, the anterior of the cell can contract. The rest of the body is unciliated, except for a ''telotroch band'' circling the posterior in mobile species and stages. Order Sessilida The larger order of Peritrichia are the Sessilida. Most of these have modified posterior kinetosomes which secrete a contractile stalk. The unattached stage, called a telotroch, is mouthless. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astomatia
Astomes (order Astomatida) are a group of ciliate eukaryotes commonly found in the guts of annelid worms, especially oligochaetes, and other invertebrates. As their name implies, these parasites are characterized by an absence of mouth. The cell is covered by uniform cilia; in addition, some astomes attach themselves to their hosts by suckers, while others use various hooks or barbs. Asexual reproduction is by transverse fission. In some cases, chains of individuals form by repeated fission without separation of the cells. The sexual phenomenon of conjugation Conjugation or conjugate may refer to: Linguistics *Grammatical conjugation, the modification of a verb from its basic form * Emotive conjugation or Russell's conjugation, the use of loaded language Mathematics *Complex conjugation, the change ... also occurs. Representative genera include '' Cepedietta'', which lives in the amphibian digestive system, and '' Radiophrya''. References Oligohymenophorea [Baidu] |
Hymenostomatia
The hymenostomes are an order of ciliate protozoa. Most are free-living in freshwater, such as the commonly studied genus ''Tetrahymena'', but some are parasitic on fish or aquatic invertebrates. Among these is the important species ''Ichthyophthirius multifiliis'', a common cause of death in aquaria and fish farms. The hymenostomes are fairly typical members of the Oligohymenophorea. Their body cilia are mostly uniform, sometimes with a few long caudal cilia, and arise from monokinetids or from dikinetids at the anterior. The oral cilia are in general distinctly tetrahymenal, with three membranelles and a paroral membrane, which corresponds only to the middle segment of the tripartite membranes found in certain scuticociliates. Mouth formation during cell division usually begins next to a postoral kinety. The hymenostomes were first defined by Delage Delage was a French luxury automobile and racecar company founded in 1905 by Louis Delâge in Levallois-Perret ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peniculid
The peniculids are an order of ciliate protozoa, including the well-known ''Paramecium'' and related genera, such as '' Frontonia'', '' Stokesia'', '' Urocentrum'' and '' Lembadion''. Most are relatively large, freshwater forms that feed by sweeping smaller organisms into the mouth. They have weird life cycles, and in many cases do not even form resting cysts. Typically the body has uniform, dense cilia, which also cover a vestibule preceding the mouth. Extrusomes are characteristically in the form of spindle trichocysts, which release thread-like shafts, and never mucocysts. The oral cilia include peniculi, corresponding to the membranelles of related groups, arranged parallel to the mouth deep in the oral cavity. Nematodesmata (rods) arise from the bases of the oral or perioral cilia, but these do not support a cyrtos as in some other classes. Two suborders are recognised: * The Frontoniina typically have a shallow oral cavity, with a long paroral membrane and denser s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astome
Astomes (order Astomatida) are a group of ciliate eukaryotes commonly found in the guts of annelid worms, especially oligochaetes, and other invertebrates. As their name implies, these parasites are characterized by an absence of mouth. The cell is covered by uniform cilia; in addition, some astomes attach themselves to their hosts by suckers, while others use various hooks or barbs. Asexual reproduction is by transverse fission. In some cases, chains of individuals form by repeated fission without separation of the cells. The sexual phenomenon of conjugation Conjugation or conjugate may refer to: Linguistics *Grammatical conjugation, the modification of a verb from its basic form * Emotive conjugation or Russell's conjugation, the use of loaded language Mathematics *Complex conjugation, the change ... also occurs. Representative genera include '' Cepedietta'', which lives in the amphibian digestive system, and '' Radiophrya''. References Oligohymenophorea [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 denitrifying obligate endosymbiont An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apostome
The Apostomatida are an order of ciliates from the class Oligohymenophorea. Individual organisms from this the order are called apostomes. They are symbiotic with Crustacea. For majority of their life cycle they are dormant and encysted on their host's exoskeleton. The life cycle of apostomes varies; most genera will multiply through the biological process of fission causing the larvae to develop within the crustacean host. Physical characteristics may include a small cytostome (mouth), often accompanied by a glandular rosette and sparse hair like projections (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 projecti ...) arranged in spiral rows on the organism. References * * Ciliate orders {{ciliate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paramecium Aurelia
''Paramecium aurelia'' are unicellular organisms belonging to the genus ''Paramecium'' of the phylum Ciliophora. They are covered in cilia which help in movement and feeding.''Paramecium'' can reproduce sexually, asexually, or by the process of endomixis. ''Paramecium aurelia'' demonstrate a strong “sex reaction” whereby groups of individuals will cluster together, and emerge in conjugant pairs. This pairing can last up to 12 hours, during which the micronucleus of each organism will be exchanged. In ''Paramecium aurelia'', a cryptic species complex was discovered by observation.Sonneborn, T. M. (1975) The Paramecium-aurelia complex of 14 sibling species. Transactions of American Microscope Society, 94: 155–178. Since then, some have tried to decode this complex using genetic data. Physical characteristics "The hair-like cilia that cover the outer body of the paramecium are in constant motion, helping the organism move along at a speed of four times its own length per s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monokinetid
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