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Oxymonad
The Oxymonads (or Oxymonadida) are a group of flagellated protozoa found exclusively in the intestines of termites and other wood-eating insects. Along with the similar parabasalid flagellates, they harbor the symbiotic bacteria that are responsible for breaking down cellulose. It includes ''Dinenympha'', '' Pyrsonympha'', and '' Oxymonas''. Characteristics Most Oxymonads are around 50 μm in size and have a single nucleus, associated with four flagella. Their basal bodies give rise to several long sheets of microtubules, which form an organelle called an axostyle, but different in structure from the axostyles of parabasalids. The cell may use the axostyle to swim, as the sheets slide past one another and cause it to undulate. An associated fiber called the preaxostyle separates the flagella into two pairs. A few oxymonads have multiple nuclei, flagella, and axostyles. Relationship to Trimastix The free-living flagellate ''Trimastix'' is closely related to the oxymonads. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monocercomonoides
''Monocercomonoides'' is a genus of flagellate Excavata belonging to the order Oxymonadida. It was established by Bernard V. Travis and was first described as those with "polymastiginid flagellates having three anterior flagella and a trailing one originating at a single basal granule located in front of the anteriorly positioned nucleus, and a more or less well-defined axostyle". It is the first eukaryotic genus to be found to completely lack mitochondria, and all hallmark proteins responsible for mitochondrial function. The genus also lacks any other mitochondria related organelles (MROs) such as hydrogenosomes or mitosomes. Data suggests that the absence of mitochondria is not an ancestral feature, but rather due to secondary loss. ''Monocercomonoides ''sp. was found to obtain energy through an enzymatic action of nutrients absorbed from the environment. The genus has replaced the iron-sulfur cluster assembly pathway with a cytosolic sulfur mobilization system, likely ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamonad
The metamonads are microscopic eukaryotic organisms, a large group of flagellate amitochondriate Loukozoa. Their composition is not entirely settled, but they include the retortamonads, diplomonads, and possibly the parabasalids and oxymonads as well. These four groups are all anaerobic (many being aerotolerant anerobes), occurring mostly as symbiotes or parasites of animals, as is the case with ''Giardia lamblia'' which causes diarrhea in mammals. Characteristics A number of parabasalids and oxymonads are found in termite guts, and play an important role in breaking down the cellulose found in wood. Some other metamonads are parasites. These flagellates are unusual in lacking mitochondria. Originally they were considered among the most primitive eukaryotes, diverging from the others before mitochondria appeared. However, they are now known to have lost mitochondria secondarily, and retain both organelles and nuclear genes derived from them. Mitochondrial relics include h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flagellate
A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their means of motion. The term presently does not imply any specific relationship or classification of the organisms that possess flagella. However, the term "flagellate" is included in other terms (such as " dinoflagellate" and " choanoflagellata") which are more formally characterized. Form and behavior Flagella in eukaryotes are supported by microtubules in a characteristic arrangement, with nine fused pairs surrounding two central singlets. These arise from a basal body. In some flagellates, flagella direct food into a cytostome or mouth, where food is ingested. Flagella often support hairs, called mastigonemes, or contain rods. Their ultrastructure plays an important role in classifying eukaryotes. Among protoctists and micros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excavata
Excavata is a major supergroup of unicellular organisms belonging to the domain Eukaryota. It was first suggested by Simpson and Patterson in 1999 and introduced by Thomas Cavalier-Smith in 2002 as a formal taxon. It contains a variety of free-living and symbiotic forms, and also includes some important parasites of humans, including ''Giardia'' and ''Trichomonas''. Excavates were formerly considered to be included in the now obsolete Protista kingdom. They are classified based on their flagellar structures, and they are considered to be the most basal flagellate lineage. Phylogenomic analyses split the members of Excavata into three different and not all closely related groups: Discobids, Metamonads and Malawimonads. Except for Euglenozoa, they are all non-photosynthetic. Characteristics Most excavates are unicellular, heterotrophic flagellates. Only the Euglenozoa are photosynthetic. In some (particularly anaerobic intestinal parasites), the mitochondria have been greatly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axostyle
An axostyle is a sheet of microtubules found in certain protists. It arises from the bases of the flagella, sometimes projecting beyond the end of the cell, and is often flexible or contractile, and so may be involved in movement and provides support for the cell. Axostyles originate in association with a flagellar microtubular root and occur in two groups, the oxymonads and parabasalid The parabasalids are a group of flagellated protists within the supergroup Excavata. Most of these eukaryotic organisms form a symbiotic relationship in animals. These include a variety of forms found in the intestines of termites and cockroach ...s; they have different structures and are not homologous. Within Trichomonads the axostyle has been theorised to participate in locomotion and cell adhesion, but also karyokinesis during cell division. References {{Protist Cell biology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preaxostyla
Anaeromonadea is a class of excavates, comprising the oxymonads and ''Trimastix ''Trimastix'' is a genus of excavates, the sole occupant of the order Trimastigida. ''Trimastix'' are bacterivorous, free living and anaerobic. When first observed in 1881 by William Kent, the morphology of Trimastix was not well describedKent, ...''. Another name used is "Preaxostyla". Phylogeny and Taxonomy Based on the work of Zhang et al. 2015. References External links Tree of Life: Preaxostyla Metamonads Excavata classes {{Excavata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaeromonadea
Anaeromonadea is a class of excavates, comprising the oxymonad The Oxymonads (or Oxymonadida) are a group of flagellated protozoa found exclusively in the intestines of termites and other wood-eating insects. Along with the similar parabasalid flagellates, they harbor the symbiotic bacteria that are respons ...s and '' Trimastix''. Another name used is "Preaxostyla". Phylogeny and Taxonomy Based on the work of Zhang et al. 2015. References External links Tree of Life: Preaxostyla Metamonads Excavata classes {{Excavata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parabasalid
The parabasalids are a group of flagellated protists within the supergroup Excavata. Most of these eukaryotic organisms form a symbiotic relationship in animals. These include a variety of forms found in the intestines of termites and cockroaches, many of which have symbiotic bacteria that help them digest cellulose in woody plants. Other species within this supergroup are known parasites, and include human pathogens. Characteristics The flagella are arranged in one or more clusters near the anterior of the cell. Their basal bodies are linked to parabasal fibers that attach to prominent Golgi complexes, distinctive to the group. Usually they also give rise to a sheet of cross-like microtubules that runs down the center of the cell and in some cases projects past the end. This is called the axostyle, but is different in structure from the axostyles of oxymonads. Parabasalids are anaerobic, and lack mitochondria, but this is now known to be a result of secondary loss, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimastix
''Trimastix'' is a genus of excavates, the sole occupant of the order Trimastigida. ''Trimastix'' are bacterivorous, free living and anaerobic. When first observed in 1881 by William Kent, the morphology of Trimastix was not well describedKent, W. S. (1881). A manual of the infusoria: including a description of all known flagellate, ciliate, and tentaculiferous protozoa, British and foreign, and an account of the organization and affinities of the sponges (Vol. 1). David Bogue, London, England. but over time the oral structure and flagellar organization have become clearer.Brugerolle, G., & Patterson, D. (1997). Ultrastructure of Trimastix convexa Hollande, an amitochondriate anaerobic flagellate with a previously undescribed organization. European Journal of Protistology, 33(2), 121-130. There are few known species, and the genus's role in the ecosystem is largely unknown. However, it is known that they generally live in marine environments within the tissues of decaying organism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
