|
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 that 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karyorelictea
Karyorelictea is a class (biology), 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 order (biology), orders were defined morphology (biology), 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 dimorphi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirostomum
''Spirostomum'' is a genus of ciliated protists in the class Heterotrichea. It is known for being very contractile.Fernandes, N.M.; da Silva Neto, I.D. (2013). “Morphology and 18S rDNA gene sequence of ''Spirostomum minus'' and ''Spirostomum teres'' (Ciliophora: Heterotrichea) from Rio de Janeiro, Brazil”. ''Zoologia'' 30: 72-79doi: 10.1590/S1984-46702013000100009 Having been first identified by Christian Gottfried Ehrenberg in 1834, further research has identified eight additional true morphospecies.Bishop, A. (1923). “Some observations upon ''Spirostomum ambiguum'' (Ehrenberg)”. ''Journal of Cell Science'' 267: 391-434doi: 10.1242/jcs.s2-67.267.391/ref>Fokin, S. (2004). “A brief history of ciliate studies (late XVII the first third of the XX century)”''Protistology'' 3: 283-296./ref>Boscaro, V.; Carducci, D.; Barbieri, G.; Senra, M.V.X.; Andreoli, I.; Erra, F.; Petroni, G.; Verni, F.; Fokin, S.I. (2014). “Focusing on genera to improve species identification: revis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blepharismidae
Blepharismidae is a family of unicellular ciliate protists found in fresh and salt water. Two genera are recognized: '' Blepharisma'', which contains some model organisms, and ''Pseudoblepharisma'' (monotypic in most sources) '' Parablepharisma'' was part of the family, but more careful inspection (morphological and molecular) has placed it in a separate class distinct from the heterotrichs. Acquisition of ribosomal sequences from ''Pseudoblepharisma'' in 2021 and 2022 also produces phylogenetic results incongruent with current taxonomy, instead placing the genus sister to ''Spirostomum ''Spirostomum'' is a genus of ciliated protists in the class Heterotrichea. It is known for being very contractile.Fernandes, N.M.; da Silva Neto, I.D. (2013). “Morphology and 18S rDNA gene sequence of ''Spirostomum minus'' and ''Spirostomum te ...''. References {{Taxonbar, from=Q18670525 Heterotrichea Taxa described in 1985 Ciliate families ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Kahl
Alfred Detlef Fritz Kahl (18 February 1877 – November, 1946) was a German schoolteacher who took up microscopy in mid-life and became a leading authority on ciliated protozoa. In a burst of scientific productivity that lasted just nine years, he published 1800 pages of scholarly work, in which he described 17 new ciliate families, 57 genera, and about 700 previously unknown species. During his brief career as a protozoologist, he redescribed and illustrated nearly all the species of ciliates known in his time, and fit them into a taxonomic scheme that remains influential today.Foissner, Wilhelm. Life and Legacy of an Outstanding Ciliate Taxonomist, Alfred Kahl (1877-1946), Including a Facsimile of his Forgotten Monograph from 1943. Acta Protozoologica 2004 (Suppl.) 43: 1-69Corliss, John O. A Salute to Fifty-Four Great Microscopists of the Past: A Pictorial Footnote to the History of Protozoology. Part II. Transactions of the American Microscopical Society. 98: 1 (Jan, 1979), pp. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stentor Roeselii
''Stentor roeselii'' is a free-living ciliate species of the genus ''Stentor (ciliate), Stentor'', in the Class (biology), class Heterotrichea. It is a common and widespread protozoan, found throughout the world in freshwater ponds, lakes, rivers and ditches. Appearance and Characteristics ''S. roeselii'' is found in still or slow-moving bodies of water, where it feeds on bacteria, flagellates, algae, and other ciliates. When feeding, the cell is fixed in place (Sessility (motility), sessile), attached by a posterior "holdfast" organelle to a firm surface such as plant stem or submerged detritus. Attached specimens are trumpet-shaped, and very contractile. When swimming freely, cells are compactly ovoid. Fully stretched out specimens are usually between 500 and 1200 micrometres in length, but size is extremely variable. It is a colourless species, with no pigmentation in the cell cortex. The body of the organism is covered with 40-80 longitudinal rows of cilia, and the oral re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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 two subtypes, 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 pai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stentor Coeruleus
''Stentor coeruleus'' () is a protist in the family Stentoridae which is characterized by being a very large ciliate that measures 0.5 to 2 millimetres when fully extended. ''S. coeruleus'' specifically appears as a very large trumpet. It contains a macronucleus that looks like a string of beads that are contained within a ciliate that is blue to blue-green in color. It has the ability to contract into a ball through the contraction of its many myonemes . ''Stentor coeruleus'' is known for its regenerative abilities. When this organism is cut in half, each half is able to regenerate a cell that has its normal anatomy provided that each cut part includes some of the macro-nucleus. It feeds by means of cilia that carry food into the gullet. DNA The genetic code is the standard code, and not the usual form for ciliates. The introns are unusually small, only 15 or 16 nucleotides long. Reproduction ''S. coeruleus'' is capable of sexual reproduction, or conjugation, but primaril ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polykinetid
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, 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 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microtubule
Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nanometer, nm and have an inner diameter between 11 and 15 nm. They are formed by the polymerization of a Protein dimer, dimer of two globular proteins, Tubulin#Eukaryotic, alpha and beta tubulin into #Structure, protofilaments that can then associate laterally to form a hollow tube, the microtubule. The most common form of a microtubule consists of 13 protofilaments in the tubular arrangement. Microtubules play an important role in a number of cellular processes. They are involved in maintaining the structure of the cell and, together with microfilaments and intermediate filaments, they form the cytoskeleton. They also make up the internal structure of cilia and flagella. They provide platforms for intracellular transport and are involved in a variety of cellular processes, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetosome
A basal body (synonymous with basal granule, kinetosome, and in older cytological literature with blepharoplast) is a protein structure found at the base of a eukaryotic undulipodium (cilium or flagellum). The basal body was named by Theodor Wilhelm Engelmann in 1880. It is formed from a centriole and several additional protein structures, and is, essentially, a modified centriole. The basal body serves as a nucleation site for the growth of the axoneme microtubules. Centrioles, from which basal bodies are derived, act as anchoring sites for proteins that in turn anchor microtubules, and are known as the microtubule organizing center (MTOC). These microtubules provide structure and facilitate movement of vesicles and organelles within many eukaryotic cells. Assembly, structure Cilia and basal bodies form during quiescence or the G1 phase of the cell cycle. Before the cell enters G1 phase, i.e. before the formation of the cilium, the mother centriole serves as a component of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dikinetid
{{Short pages monitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
