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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. Characteristics 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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mobilida
Mobilida is a group of parasitic or symbiotic peritrich ciliates, comprising more than 280 species. Mobilids live on or within a wide variety of aquatic organisms, including fish, amphibians, molluscs, cnidarians, flatworms and other ciliates, attaching to their host organism by means of an aboral adhesive disk. Some mobilid species are pathogens of wild or farmed fish, causing severe and economically damaging diseases such as trichodinosis. Morphology and Feeding As the name suggests, mobilida cells are mobile, capable of moving about on the body of a host organism, and of swimming between hosts. This sets them apart from the predominantly sessile peritrichs of the order Sessilida, such as Vorticella and Epistylis, which, during the feeding, or vegetative, phase of the life cycle remain attached to submerged surfaces, often by means of a stalk. Like all peritrichs, the mobilids possess a spiral wreathe of cilia running counterclockwise around the oral region (peristome ... [...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 microorganisms that are usually free-living and can be found in freshwater, marine, and soil habitats. 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 crustaceans. Since 2022 there have also been several reports that scuticociliates might be responsible for mass die-off events of sea urchin Sea urchins or urchins () are echinoderms in the class (biology), class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body cove ...s across the world's oceans. References * * External links * Oligohymeno ... [...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 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, including anoxic and oxygen-depleted habitats. 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 paras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoothamnium Niveum
''Zoothamnium niveum'' is a species of ciliate protozoan which forms feather-shaped colonies in marine coastal environments. The ciliates form a symbiosis with sulfur-oxidizing chemosynthetic bacteria of the species "''Candidatus'' Thiobios zoothamnicoli", which live on the surface of the colonies and give them their unusual white color. Characteristics The conspicuously white and feather-shaped colonies are composed of individual bell-shaped cells known as zooids. The stalks of individual cells grow from a single central stalk. Colonies can reach a length of up to 15 mm, formed from hundreds of single zooids, each with a length of only 120 μm. An entire colony can contract into a ball-shaped bunch through the contraction of myonemes in their stalks. The white color is produced by chemolithoautotrophic sulfur-oxidizing bacteria, which cover the entire surface of the ''Z. niveum'' colony. In most other species of ''Zoothamnium'', bacteria are only known to cover the ... [...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 (ciliate), Stokesia'', ''Urocentrum'' and ''Lembadion''. Most are relatively large, freshwater forms that feed by sweeping smaller organisms into the mouth. They have simple life cycles, and in many cases do not even form microbial cyst, 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 ... [...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 also occurs. Representative genera include '' Cepedietta'', which lives in the amphibian digestive system The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller compone ..., and '' Radiophrya''. References Oligohymenophorea [Baidu] |
Hymenostomatida
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 aquarium, aquaria and fish farming, 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 Yves Delage, Delage & Edgard Hérouard, Hérouard in 1896. Initially the scuticociliates and peniculids we ... [...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 also occurs. Representative genera include '' Cepedietta'', which lives in the amphibian digestive system The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller compone ..., and '' Radiophrya''. References Oligohymenophorea [Baidu] |
Apostomatida
The Apostomatida are an order of ciliates from the class Oligohymenophorea. Individual organisms from this 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 (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...) arranged in spiral rows on the organism. References * * Ciliate orders {{ciliate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [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. 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 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 (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...) arranged in spiral rows on the organism. References * * Ciliate orders {{ciliate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
