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Merocystis
''Merocystis'' is a genus in the phylum Apicomplexa. History This genus was created in 1911 by DakinDakin WJ (1911) Notes on a new coccidian ''Merocystis kathae'' (n. gen. et sp.,) occurring in the renal organ of the whelk. Arch. Protist XXIII: 1115 He discovered this parasite - ''Merocystis kathae'' - in the renal organ of the whelk (''Buccinum undatum''). Its life cycle has been studied in some detail by other workers. A second species was described - ''Merocystis tellinovum'' - by Buchanan in 1979 but this has since been moved to the genus ''Pseudoklossia''. Taxonomy There is one species known in this genus. Description The life cycle follows a seasonal course. The earliest stages may appear in the kidney any time between March and June. Growth proceeds and sexual differentiation takes place but mature gametes are not found until November, when the first stages of sporogony are first found. Mature spores containing sporozoites are formed in January and become increasingly ... [...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] |
Apicomplexa Genera
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 (''Cystoisospora ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus comes above species and below family (taxonomy), family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microgamete
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Sporozoite
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 typified by a ''cellular variety'' with a distinct morphology and biochemistry. Not all apicomplexa develop all the following cellular varieties and division methods. This presentation is intended as an outline of a hypothetical generalised apicomplexan organism. Methods of asexual replication Apicomplexans (sporozoans) replicate via ways of multiple fission (also known as schizogony). These ways include , and , although the latter is sometimes referred to as schizogony, despite its general meaning. Merogony is an asexually reproductive process of apicomplexa. After infecting a host cell, a trophozoite ( see glossary below) increases in size while repeatedly replicating its nucleus and other organelles. During this process, the org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apicomplexa Lifecycle Stages
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 typified by a ''cellular variety'' with a distinct morphology and biochemistry. Not all apicomplexa develop all the following cellular varieties and division methods. This presentation is intended as an outline of a hypothetical generalised apicomplexan organism. Methods of asexual replication Apicomplexans (sporozoans) replicate via ways of multiple fission (also known as schizogony). These ways include , and , although the latter is sometimes referred to as schizogony, despite its general meaning. Merogony is an asexually reproductive process of apicomplexa. After infecting a host cell, a trophozoite ( see glossary below) increases in size while repeatedly replicating its nucleus and other organelles. During this process, the orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oocyst
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 typified by a ''cellular variety'' with a distinct morphology and biochemistry. Not all apicomplexa develop all the following cellular varieties and division methods. This presentation is intended as an outline of a hypothetical generalised apicomplexan organism. Methods of asexual replication Apicomplexans (sporozoans) replicate via ways of multiple fission (also known as schizogony). These ways include , and , although the latter is sometimes referred to as schizogony, despite its general meaning. Merogony is an asexually reproductive process of apicomplexa. After infecting a host cell, a trophozoite ( see glossary below) increases in size while repeatedly replicating its nucleus and other organelles. During this process, the or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sporoblast
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Cone
A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines connecting a common point, the apex, to all of the points on a base that is in a plane that does not contain the apex. Depending on the author, the base may be restricted to be a circle, any one-dimensional quadratic form in the plane, any closed one-dimensional figure, or any of the above plus all the enclosed points. If the enclosed points are included in the base, the cone is a solid object; otherwise it is a two-dimensional object in three-dimensional space. In the case of a solid object, the boundary formed by these lines or partial lines is called the ''lateral surface''; if the lateral surface is unbounded, it is a conical surface. In the case of line segments, the cone does not extend beyond the base, while in the case of half-lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spindle (textiles)
A spindle is a straight spike usually made from wood used for spinning (textiles), spinning, twisting fibers such as wool, flax, hemp, cotton into Thread (yarn), yarn. It is often weighted at either the bottom, middle, or top, commonly by a disc or spherical object called a spindle whorl, whorl; many spindles, however, are weighted simply by thickening their shape towards the bottom, e.g. Orenburg and French spindles. The spindle may also have a hook, groove, or notch at the top to guide the yarn. Spindles come in many different sizes and weights depending on the thickness of the yarn one desires to spin. History The origin of the first wooden spindle is lost to history because the materials did not survive. Whorl-weighted spindles date back at least to Neolithic times; spindle whorls have been found in archaeological digs around the world. A spindle is also part of traditional spinning wheels where it is horizontal, such as the Indian charkha and the great or walking wheel. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Nucleus
The cell nucleus (pl. nuclei; from Latin or , meaning ''kernel'' or ''seed'') is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have no nuclei, and a few others including osteoclasts have many. The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and isolates its contents from the cellular cytoplasm; and the nuclear matrix, a network within the nucleus that adds mechanical support. The cell nucleus contains nearly all of the cell's genome. Nuclear DNA is often organized into multiple chromosomes – long stands of DNA dotted with various proteins, such as histones, that protect and organize the DNA. The genes within these chromosomes are structured in such a way to promote cell function. The nucleus maintains the integrity of genes and controls the activities of the cell by regulating gene expres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygote
A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicellular organisms, the zygote is the earliest developmental stage. In humans and most other anisogamous organisms, a zygote is formed when an egg cell and sperm cell come together to create a new unique organism. In single-celled organisms, the zygote can divide asexually by mitosis to produce identical offspring. German zoologists Oscar and Richard Hertwig made some of the first discoveries on animal zygote formation in the late 19th century. Humans In human fertilization, a released ovum (a haploid secondary oocyte with replicate chromosome copies) and a haploid sperm cell (male gamete) combine to form a single diploid cell called the zygote. Once the single sperm fuses with the oocyte, the latter completes the division of the second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
