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Archigregarines
The ''Archigregarinorida'' are an order of parasitic alveolates in the phylum Apicomplexa. Species in this order infect marine invertebrates — usually annelids, ascidians, hemichordates and sipunculids. Taxonomy This order was redefined by Levine in 1971. The order currently consists of 76 species in two families — '' Exoschizonidae'' and '' Selenidioididae''. The family ''Exoschizonidae'' contains one genus — '' Exoschizon'' — which has one species. The family '' Selenidioididae'' has six genera: ''Filipodium'' with 3 species, '' Merogregarina'' with one species, '' Meroselenidium'' with one species, ''Platyproteum'' with one species, '' Selenidioides'' with 11 species and ''Veloxidium'' with one species. Phylogenetics DNA studies suggest that the archigregarines are ancestral to the other gregarines. Phylogenetic analysis suggests that this group is paraphyletic and will need division. The Neogregarinorida appear to be derived from the Eugregarinorida. Assuming th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apicomplexa
The Apicomplexa (also called Apicomplexia) are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of non-photosynthetic plastid called an apicoplast, and an apical complex structure. The organelle is an adaptation that the apicomplexan applies in penetration of a host cell. The Apicomplexa are unicellular and spore-forming. All species are obligate endoparasites of animals, except '' Nephromyces'', a symbiont in marine animals, originally classified as a chytrid fungus. Motile structures such as flagella or pseudopods are present only in certain gamete stages. The Apicomplexa are a diverse group that includes organisms such as the coccidia, gregarines, piroplasms, haemogregarines, and plasmodia. Diseases caused by Apicomplexa include: * Babesiosis (''Babesia'') * Malaria (''Plasmodium'') * Cryptosporidiosis (''Cryptosporidium parvum'') * Cyclosporiasis (''Cyclospora cayetanensis'') * Cystoisosporiasis (''Cystoisosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exoschizonidae
The Exoschizonidae are a family in the phylum Apicomplexa. History This family was created by Levine in 1971.Levine ND (1971) Taxonomy of the Archigregarinorida and Selenidiidae (Protozoa, Apicomplexa) J Euk Microbiol 18 (4) 704–717 Taxonomy There is one genus currently recognised in this family - '' Exoschizon''. This genus has only one species - '' Exoschizon siphonosomae'' - which was described by Hukui in 1939.Hukui (1939) J Fac Sci Hiroshima Univ 7: 17 Description This species was found in the intestine of a sipunculid worm ('' Siphonosoma cumanense'') in Japan. The meront Apicomplexans, a group of intracellular parasites, have life cycle stages that allow them to survive the wide variety of environments they are exposed to during their complex life cycle. Each stage in the life cycle of an apicomplexan organism is ...s measure . There are ~13 longitudinal striations per side. The meronts and gamonts are similarly shaped. Transmission is presumably by the orof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenidioides
''Selenidioides'' are a genus of parasitic alveolates in the phylum Apicomplexa The Apicomplexa (also called Apicomplexia) are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of non-photosynthetic plastid called an apicoplast, and an apical complex structure. Th .... Species in this genus infect marine invertebrates. Taxonomy The order Archigregarinorida was redefined by Levine in 1971.Levine N D (1971) Taxonomy of the Archigregarinorida and Selenidiidae (Protozoa, Apicomplexa) J Euk Micro 18 (4) 704-717 DOI: 10.1111/j.1550-7408.1971.tb03401.x This reorganisation lead to the creation of two new families ( Exoschizonidae and Selenidioididae) and several genera including ''Selenidioides''. There are 11 species in this genus. Life cycle The parasites in the genus infect the gastrointestinal tract and are presumably transmitted by the orofaecal route but the details of this mechanism are presently unknown. Refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crista
A crista (; plural cristae) is a fold in the inner membrane of a mitochondrion. The name is from the Latin for ''crest'' or ''plume'', and it gives the inner membrane its characteristic wrinkled shape, providing a large amount of surface area for chemical reactions to occur on. This aids aerobic cellular respiration, because the mitochondrion requires oxygen. Cristae are studded with proteins, including ATP synthase and a variety of cytochromes. Background With the discovery of the dual-membrane nature of mitochondria, the pioneers of mitochondrial ultrastructural research proposed different models for the organization of the mitochondrial inner membrane. Three models proposed were: *Baffle model – According to Palade (1953), the mitochondrial inner membrane is convoluted in a baffle-like manner with broad openings towards the intra-cristal space. This model entered most textbooks and was widely believed for a long time. *Septa model – Sjöstrand (1953) suggested that she ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondria
A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'' was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase coined by Philip Siekevitz in a 1957 article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). A large number of unicellular organisms, such as microsporidia, parabasalids and diplomonads, have reduced or transformed their mitochondria into mitosome, other structures. One eukaryote, ''Monocercomonoides'', is known to have completely lost its mitocho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Host (biology)
In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasite, parasitic, a mutualism (biology), mutualistic, or a commensalism, commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include animals playing host to parasitic worms (e.g. nematodes), cell (biology), cells harbouring pathogenic (disease-causing) viruses, a Fabaceae, bean plant hosting mutualistic (helpful) Rhizobia, nitrogen-fixing bacteria. More specifically in botany, a host plant supplies nutrient, food resources to micropredators, which have an evolutionarily stable strategy, evolutionarily stable relationship with their hosts similar to ectoparasitism. The host range is the collection of hosts that an organism can use as a partner. Symbiosis Symbiosis spans a wide variety of possible relationships between organisms, differing in their permanence and their effects on the two parties. If one of the partners in an ass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoxenous
Monoxenous development, or monoxeny, characterizes a parasite whose development is restricted to a single host species. The etymology of the terms monoxeny / monoxenous derives from the two ancient Greek words (), meaning "unique", and (), meaning "foreign". In a monoxenous life cycle, the parasitic species may be strictly host specific (using only a single host species, such as gregarines) or not (e.g. ''Eimeria'', ''Coccidia Coccidia (Coccidiasina) are a subclass of microscopic, spore-forming, single-celled obligate intracellular parasites belonging to the apicomplexan class Conoidasida. As obligate intracellular parasites, they must live and reproduce within an a ...''). References External links xeno-, xen- word info Parasitism {{parasite-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meiosis
Meiosis (; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately result in four cells with only one copy of each chromosome ( haploid). Additionally, prior to the division, genetic material from the paternal and maternal copies of each chromosome is crossed over, creating new combinations of code on each chromosome. Later on, during fertilisation, the haploid cells produced by meiosis from a male and female will fuse to create a cell with two copies of each chromosome again, the zygote. Errors in meiosis resulting in aneuploidy (an abnormal number of chromosomes) are the leading known cause of miscarriage and the most frequent genetic cause of developmental disabilities. In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells, each with half the number of chr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broad range of environments. Less formally, they are categorized as Helminths, but are taxonomically classified along with Arthropod, arthropods, Tardigrade, tardigrades and other moulting animalia, animals in the clade Ecdysozoa, and unlike platyhelminthe, flatworms, have tubular digestion, digestive systems with openings at both ends. Like tardigrades, they have a reduced number of Hox genes, but their sister phylum Nematomorpha has kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum. Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species described to date vary by author and may change rapidly over ... [...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 nm and have an inner diameter between 11 and 15 nm. They are formed by the polymerization of a dimer of two globular proteins, alpha and beta tubulin into 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, including the movement of secretory vesicles, organell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemosporidia
Haemosporidiasina (Haemosporidia) is a subclass of apicomplexans described by Jacques Euzéby in 1988.Euzéby, J. (1988) Comparative Medical Protozoology, Vol. 3: Apicomplexa, 2: Haemosporidioses, Part 1: Plasmodiids, Haemoproteids, "Piroplasms" (general characters) The taxon is very similar to Aconoidasida. Taxonomy Haemosporidiasina is divided into 2 orders: Order Chromatorida (with pigmented intraerythrocytic parasites) Suborder Laveraniina *Family Plasmodiidae ** Genus ''Bioccala'' Landau ''et al'' 1984 ** Genus ''Biguetiella'' Landau ''et al'' 1984 ** Genus ''Billbraya'' Paperna & Landau 1990 ** Genus ''Dionisia'' Landau ''et al'' 1980 ** Genus ''Hepatocystis'' Miller 1908 ** Genus ''Mesnilium'' Misra, Haldar & Chakravarty 1972 ** Genus ''Nycteria'' Garnham and Heisch 1953 ** Genus ''Plasmodium'' Marchiafava & Celli 1885 ** Genus ''Polychromophilus'' Landau ''et al'' 1984 ** Genus ''Rayella'' Dasgupta 1967 ** Genus ''Saurocytozoon'' Lainson & Shaw 1969 ** Genus ''Vetufe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugregarinorida
The ''Eugregarinorida'' are the most large and diverse order of gregarines — parasitic protists belonging to the phylum Apicomplexa. Eugregarines are found in marine, freshwater and terrestrial habitats. These species possess large trophozoites that are significantly different in morphology and behavior from the sporozoites. This taxon contains most of the known gregarine species. These protozoa are common parasites of many invertebrates including insects and polychete worms. Taxonomy Eugregarinorida has three recognised suborders: Aseptatorina, Blastogregarinorina and Septatorina. The intestinal eugregarines are separated into septate — suborder Septatina — and aseptate — suborder Aseptatina — depending on whether the trophozoite is superficially divided by a transverse septum. The marine gregarines are the most poorly studied members of this order. The eugregarines have been classified into 27 families with ~244 genera, 14 of which have more than 25 species each. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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