Auranticordis quadriverberis
| Auranticordis quadriverberis | ||||||||||||
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Auranticordis quadriverberis |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Auranticordis | ||||||||||||
| Chantangsi, Esson & Leander, 2008 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Auranticordis quadriverberis | ||||||||||||
| Chantangsi , Esson & Leander , 2008 | ||||||||||||
Auranticordis quadriverberis is a heterotrophic flagellate from the Cercozoa group . It is the only species of the genus Auranticordis and isassigned to the tribe Cercozoain an uncertain position . It differs from the other Cercozoen through its orange coloration and the probable primary endosymbiosis with a blue algae .
features
Appearance and movement
The cells can change their shape slightly and are lobed, heart-shaped, or egg-shaped. The cell size ranges from 35 to 75 micrometers. The front end is narrower, the wider rear end consists of four larger lobes. One flap is smaller than the other three, on its right side, on the abdomen, there is a depression, and to the left of it a pit in which the flagella are located. Instead of the usual two at Cercozoa, Auranticordis has four flagella that reach back in the aforementioned pit. The flagella arise from an apically located pocket. They run along the pit to the rear and are therefore almost invisible with a light microscope. They are arranged in two pairs and are covered with flagellated hair or mastigonemen . All flagella are approximately the same length and slightly longer than the cell. They strike similarly and ensure that the cells slide over the substrate. Pseudopodia are not known.
The cells are colored orange. This is due to the presence of linearly arranged orange-colored, mucus-carrying bodies that are distributed over the entire cell surface. These are small compartments around 780 nanometers in diameter that are located directly under the cell membrane. Other Extrusomen come at Auranticordis not available.
The surface of the cells is ribbed and consists of around 80 longitudinal ribs. The openings of the mucous bodies open into the furrows in between. Under each rib there is a single row of microtubules that are likely responsible for changing the shape of the cell. There is no cell wall or shell on the outside of the cell.
The type of food consumed is not known. Ingested bacteria were observed inside the cell .
Cell interior
Auranticordis quadriverberis has a large nucleus of 15 to 20 micrometers in diameter, which is located in the front area of the cell. There are several conspicuous nucleoli in it . Condensed chromosomes, as found in many Cercozoa, do not occur here. At the forward end, the cell nucleus is pointed and connected with a striped band that is located near the basal body and the microtubule roots. The nucleus is clearly indented on one side.
Near the front end there are still black material of unknown origin and function, lipid globules and Golgi apparatus . Mitochondria with tubular cristae are not yet known, but a number of elongated bodies near the cell surface are reminiscent of acristate mitochondria. This is interpreted as a degenerate form in connection with the oxygen-poor environment or as a possible preparation artifact . The structures are 135 to 185 nanometers long and therefore much smaller than the mitochondria of other Cercozoa.
Orange bodies as possible endosymbionts
The cells each contain 2 to 30 orange bodies of variable shape and around 4 to 5 micrometers in diameter. Some are up to 14 micrometers long. They are distributed over the whole cell, but concentrated in the front area. Each body is enveloped by two compressed inner membranes, which in turn are surrounded by sac-like vesicles. The innermost membrane turns inside the body and forms several, non-stacked thylakoids in the outer area of the body. There are no membranes in the center of the body, it contains an electron-dense area in which there are tailed viral particles . The orange color corresponds to the plastids of some dinoflagellates or diatoms, but their ultrastructure is essentially different from these plastids. The characteristics of the orange bodies can be reconciled with three possible identities:
- The bodies can be ingested prey that are in the first stage of digestion. However, virtually all of the objects examined were intact and not in an advanced state of digestion.
- The bodies can be temporary, photosynthetically active endosymbionts that are regularly renewed by kleptoplasty.
- The bodies can be permanently integrated, photosynthetically active endosymbionts, i.e. plastids. The presence of virus particles and the arrangement of the thylakoids indicate primary endosymbiosis with a cyanobacterium.
distribution
The species is only known from the place where it was first described. It was collected in the sands of the tidal area of Spanish Banks in Vancouver , British Columbia.
Systematics
Based on molecular genetic studies, Auranticordis quadriverberis belongs to the Cercozoa strain . Here, together with Pseudopirsonia mucosa and some uncultivated environmental specimens , it forms a group that is the sister group of the large group Cercomonadidae + Heteromitidae + Euglyphida + Thaumatomonadida .
The genus name Auranticordis means orange heart and refers to the shape and color of the cells. The species epithet quadriverberis means four flagellates .
supporting documents
- Chitchai Chantangsi, Heather J. Esson, Brian S. Leander: Morphology and molecular phylogeny of a marine interstitial tetraflagellate with putative endosymbionts: Auranticordis quadriverberis n. Gen. Et sp. (Cercozoa) . BMC Microbiology, Volume 8, 2008, Publication 123, (online)