|
Selenococcidium
''Selenococcidium'' is a genus of parasitic alveolates in the phylum Apicomplexa. There is one recognised species in this genus – ''Selenococcidium intermedium''. This species infects the intestinal tract of European lobsters (''Homarus gammarus''). The genus and species were described by Léger & Duboscq in 1909.Léger & Duboscq 1909 C. R. Acad. Sci. Paris, 149, 364 The specific name is derived from the appearance of the trophozoites which possesses aspects of both the coccidia and gregarines. Description The mechanism by which the parasites enter the gastrointestinal tract of the lobster is not known this stage may (or may not) involve an intermediate host. Within the lobster the trophozoites are vermicular in form similar those of the gregarines. These enter an enterocyte, divide three times to give rise to an octonucleate schizont. The schizont divides and gives rise to eight merozoites which then invade other enterocytes. There may be several rounds of asexual reproduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenococcidium Intermedium
''Selenococcidium'' is a genus of parasitic alveolates in the phylum Apicomplexa. There is one recognised species in this genus – ''Selenococcidium intermedium''. This species infects the intestinal tract of European lobsters (''Homarus gammarus''). The genus and species were described by Léger & Duboscq in 1909.Léger & Duboscq 1909 C. R. Acad. Sci. Paris, 149, 364 The specific name is derived from the appearance of the trophozoites which possesses aspects of both the coccidia and gregarines. Description The mechanism by which the parasites enter the gastrointestinal tract of the lobster is not known this stage may (or may not) involve an intermediate host. Within the lobster the trophozoites are vermicular in form similar those of the gregarines. These enter an enterocyte, divide three times to give rise to an octonucleate schizont. The schizont divides and gives rise to eight merozoites which then invade other enterocytes. There may be several rounds of asexual repro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eucoccidiorida
The Eucoccidiorida are an order of microscopic, spore-forming, single-celled parasites belonging to the apicomplexan class Conoidasida. Protozoans of this order include parasites of humans, and both domesticated and wild animals including birds. Among these parasites are the ''Toxoplasma gondii'' that cause toxoplasmosis and ''Isospora belli'', which results in isosporiasis. Definition This is the largest order in the class Conoidasida and contains those species that all undergo merogony (asexual), gametogony (sexual) and sporogony (spore formation) during their lifecycles. Genera Nineteen families, three subfamilies, and 70 genera are recognised in this order. The genera include: '' Adelea'', '' Adelina'', ''Aggregata'', '' Alveocystis'', ''Atoxoplasma'', ''Babesiosoma'', '' Barrouxia'', '' Bartazoon'', '' Besnoitia'', ''Calyptospora'', '' Caryospora'', '' Caryotropha'', '' Chagasella'', ''Choleoeimeria'', ''Cryptosporidium'', '' Crystallospora'', ''Cyclospora'', '' Cyrilia'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eimeriorina
Eimeriorina is a suborder of phylum Apicomplexa. All species in this clade are homoxenous or facultatively homoxenous. Merogony, gamogony and oocyst formation all occur within the same host. The hosts may be vertebrates or invertebrates. Erroneous identifications of species is a major problem in coccidian systematics and it is likely that some of the genera and species will be revised. Taxonomy There are 12 families, 2 subfamilies and 50 genera recognised in this suborder. The genus ''Eimeria'' with ~1500 species is the largest genus in this suborder. Notes One genus is entirely entomoxenous (parasitic on insects) — '' Barrouxia''. The taxonomic status of ''Atoxoplasma ''Atoxoplasma'' is a genus of parasitic alveolates in the phylum Apicomplexa. The species in this genus infect birds. They are spread by the orofaecal route. History This genus was created by Garnham in 1950. The history of this genus has been ...'' remains unclear. References Conoidasida SAR ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryota
Eukaryotes () are organisms whose Cell (biology), cells have a cell nucleus, nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the Three-domain system, three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard (archaea), Asgard archaea. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass (ecology), biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as Flagellated cell, flagellated phagotrophs. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gregarine
The gregarines are a group of Apicomplexan alveolates, classified as the Gregarinasina or Gregarinia. The large (roughly half a millimeter) parasites inhabit the intestines of many invertebrates. They are not found in any vertebrates. However, gregarines are closely related to both ''Toxoplasma'' and ''Plasmodium'', which cause toxoplasmosis and malaria, respectively. Both protists use protein complexes similar to those that are formed by the gregarines for gliding motility and invading target cells. This makes them excellent models for studying gliding motility with the goal of developing treatment options for toxoplasmosis and malaria. Thousands of different species of gregarines are expected to be found in insects, and 99% of these gregarines still need to be described. Each insect can be the host of multiple species. One of the most studied gregarines is ''Gregarina garnhami''. In general, gregarines are regarded as very successful parasites, as their hosts are spread over the ... [...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] |
Fertilization
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Processes such as insemination or pollination which happen before the fusion of gametes are also sometimes informally called fertilisation. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation. History In Antiquity, Aristotle conceived the formation of new individuals through fusion of male and female fluids, with form and function emerging gradually, in a mode called by him as epigenetic. In 1784, Spallanzani established the need of interaction between the female's ovum and male's sperm to form a zygote in frog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrogamete
{{Short pages monitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microgamete
{{Short pages monitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merozoite
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] |
