Myrionecta rubra

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Myrionecta rubra
Myrionecta rubra.jpg
M. rubra from north-west Black Sea
Scientific classification
Domain:
Eukaryota
(unranked):
SAR
(unranked):
Alveolata
Phylum:
Ciliophora
Class:
Litostomatea
Order:
Cyclotrichiida
Family:
Mesodiniidae
Genus:
Myrionecta
Species:
M. rubra
Binomial name
Myrionecta rubra
Lohmann, 1908
Synonyms

Halteria rubraLohmann, 1908
Mesodinium rubrumHamburger and Buddenbrock, 1929
Cyclotrichium meunieriPowers, 1932
Mesodinium pulex Bakker, 1966

Contents

Myrionecta rubra (or Mesodinium rubrum) is a species of ciliates. [1] It constitutes a plankton community and is found throughout the year, most abundantly in spring and fall, in coastal areas. Although discovered in 1908, its scientific importance came into light in the late 1960s when it attracted scientists by the recurrent red colouration it caused by forming massive blooms, [2] that cause red tides in the oceans. [3] [4]

Unlike typical protozoans, M. rubra can make its own nutrition by photosynthesis. The unusual autotrophic property was discovered in 2006 when genetic sequencing revealed that the photosynthesising organelles, plastids, were derived from the principal food of the ciliate, the photosynthetic algae called cryptomonads (or cryptophytes). [5] It is, thus, both autotrophic and heterotrophic. This nature also indicates that it is an example of endosymbiosis, supporting the endosymbiotic theory, as well as the concept of stealing of cell organelles called kleptoplastidy. [6] Moreover, M. rubra represents additional endosymbiosis by transferring its plastids to its predators, the dinoflagellate planktons belonging to the genus Dinophysis. [7] [8]

In 2009, a new species of Gram-negative bacteria called Maritalea myrionectae was discovered from a cell culture of M. rubra. [9]

Description

M. rubra is a free-living marine ciliate. It is reddish in colour and form dark-red mass during blooming. Its body is almost spherical, looking like a miniature sunflower with its radiating hair-like cilia on its body surface. It measures up to 100 μm in length and 75 μm in width. The body is superficially divided into two lobes due to formation of a constriction at the centre. The constriction gives rise to a larger anterior lobe and a smaller posterior lobe. The cilia arise from the constriction. Using the cilia it can jump about 10-20 times its body length in one movement. [10] Its nucleus is prominently situated at the centre, and is surrounded by organelles mostly derived from algae. For example, its cytoplasm contains numerous plastids, mitochondria and other nuclei. These organelles are properly separated such that the mitochondria are fully enclosed in a vacuole membrane and two endoplasmic reticulum membranes of the ciliate. [6] This indicates that the ciliate is primarily a heterotroph, but after acquiring algal plastid, it transforms into an autotroph.

The endosymbiont

Genetic analysis showed that in the American coastal areas, the primary food of M. rubra is the algae most closely related to the free-living Geminigera cryophila . [5] But in Japanese coasts, the major algal species is Teleaulax amphioxeia . [8] When these plastid-containing algae are ingested by the ciliate, they are not digested. The plastids remain functional and provide nutrition to the ciliate by photosynthesis. In order for the plastids to be normally active, they still require enzymes, which are synthesised by the sequestered algal nuclei. The single nucleus can survive and remain genetically active up to 30 days in the cytoplasm of the ciliate. [11] As the retention time of the prey nuclei is short, an average M. rubra cell may contain eight algal plastids per single prey nucleus and the nuclei need to be replaced by continuous feeding on fresh algae. Thus, the algal organelles are not permanently integrated. [5]

Related Research Articles

Chloroplast Plant organelle that conducts photosynthesis

Chloroplasts are organelles that conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in plant and algal cells. They then use the ATP and NADPH to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, much amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like Arabidopsis and wheat.

Dinoflagellate unicellular algae with two flagella

The dinoflagellates are protists constituting the phylum Dinoflagellata. Usually considered algae, dinoflagellates are mostly marine plankton, but they also are common in freshwater habitats. Their populations are distributed depending on sea surface temperature, salinity, or depth. Many dinoflagellates are known to be photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey.

Alveolate Superphylum of protists

The alveolates are a group of protists, considered a major clade and superphylum within Eukarya, and are also called Alveolata.

Cryptomonad Subphylum of algae

The cryptomonads are a group of algae, most of which have plastids. They are common in freshwater, and also occur in marine and brackish habitats. Each cell is around 10–50 μm in size and flattened in shape, with an anterior groove or pocket. At the edge of the pocket there are typically two slightly unequal flagella.

Plastid membrane-bound DNA-containing organelle found in the cytoplasm of autotrophic eukaryotes (plants, some protists) that functions as the site of manufacture and storage of important chemical compounds

The plastid is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms. They are considered endosymbiotic Cyanobacteria, related to the Gloeomargarita. Plastids were discovered and named by Ernst Haeckel, but A. F. W. Schimper was the first to provide a clear definition. Plastids are the site of manufacture and storage of important chemical compounds used by the cells of autotrophic eukaryotes. They often contain pigments used in photosynthesis, and the types of pigments in a plastid determine the cell's color. They have a common evolutionary origin and possess a double-stranded DNA molecule that is circular, like that of the circular chromosome of prokaryotic cells.

Chromista is a biological kingdom consisting of some single-celled and multicellular eukaryotic organisms, which share similar features in their photosynthetic organelles (plastids). It includes all protists such as some algae, diatoms, oomycetes, and protozoans whose plastids contain chlorophyll c. It is probably a polyphyletic group whose members independently arose as separate evolutionary group from the common ancestor of all eukaryotes. As it is assumed the last common ancestor already possessed chloroplasts of red algal origin, the non-photosynthetic forms evolved from ancestors able to perform photosynthesis. Their plastids are surrounded by four membranes, and are believed to have been acquired from some red algae.

Kleptoplasty sequestration of intact plastids from algae by predators

Kleptoplasty or kleptoplastidy is a symbiotic phenomenon whereby plastids, notably chloroplasts from algae, are sequestered by host organisms. The word is derived from Kleptes (κλέπτης) which is Greek for thief. The alga is eaten normally and partially digested, leaving the plastid intact. The plastids are maintained within the host, temporarily continuing photosynthesis and benefiting the predator. The term was coined in 1990 to describe chloroplast symbiosis.

Cryptophyceae class of algae

The cryptophyceae are a class of algae, most of which have plastids. About 220 species are known, and they are common in freshwater, and also occur in marine and brackish habitats. Each cell is around 10–50 μm in size and flattened in shape, with an anterior groove or pocket. At the edge of the pocket there are typically two slightly unequal flagella.

<i>Elysia chlorotica</i> species of mollusc

Elysia chlorotica is a small-to-medium-sized species of green sea slug, a marine opisthobranch gastropod mollusc. This sea slug superficially resembles a nudibranch, yet it does not belong to that clade of gastropods. Instead it is a member of the clade Sacoglossa, the sap-sucking sea slugs. Some members of this group use chloroplasts from the algae they eat for photosynthesis, a phenomenon known as kleptoplasty. Elysia chlorotica is one of these "solar-powered sea slugs". It lives in a subcellular endosymbiotic relationship with chloroplasts of the marine heterokont alga Vaucheria litorea.

Protozoa Diverse motile unicellular heterotrophic eukaryotic organisms

Protozoa is an informal term for single-celled eukaryotes, either free-living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris. Historically, the protozoa were regarded as "one-celled animals", because they often possess animal-like behaviors, such as motility and predation, and lack a cell wall, as found in plants and many algae. Although the traditional practice of grouping protozoa with animals is no longer considered valid, the term continues to be used in a loose way to identify single-celled organisms that can move independently and feed by heterotrophy.

<i>Dinophysis</i> genus of protists

Dinophysis is a genus of dinoflagellates common in tropical, temperate, coastal and oceanic waters. It was first described in 1839 by Christian Gottfried Ehrenberg.

Mesodinium chamaeleon is a ciliate of the genus Mesodinium. It is known for being able to consume and maintain algae endosymbiotically for days before digesting the algae. It has the ability to eat red and green algae, and afterwards using the chlorophyll granules from the algae to generate energy, turning itself from being a heterotroph into an autotroph. The species was discovered in January 2012 outside the coast of Nivå, Denmark by professor Øjvind Moestrup.

<i>Dinophysis acuminata</i> species of protist

Dinophysis acuminata is a marine plankton species of dinoflagellates that is found in coastal waters of the north Atlantic and Pacific oceans. The genus Dinophysis includes both phototrophic and heterotrophic species. D. acuminata is one of several phototrophic species of Dinophysis classed as toxic, as they produce okadaic acid which can cause diarrhetic shellfish poisoning (DSP). Okadiac acid is taken up by shellfish and has been found in the soft tissue of mussels and the liver of flounder species. When contaminated animals are consumed, they cause severe diarrhoea. D. acuminata blooms are constant threat to and indication of diarrhoeatic shellfish poisoning outbreaks.

Maritalea is a genus of Gram-negative, strictly aerobic, oxidase- and catalase-positive, rod-shaped, motile bacteria with peritrichous flagella from the family of Hyphomicrobiaceae.

Karyoklepty is a strategy for cellular evolution, whereby a predator cell appropriates the nucleus of a cell from another organism to supplement its own biochemical capabilities.

Maritalea myrionectae is a Gram-negative, rod-shaped, strictly aerobic bacterium from the genus of Maritalea which was isolated from the protist Myrionecta rubra in Kunsan in the Republic of Korea.

Mixotrophic dinoflagellate

Dinoflagellates are eukaryotic plankton, existing in marine and freshwater environments. Previously, dinoflagellates had been grouped into two categories, phagotrophs and phototrophs. Mixotrophs, however include a combination of phagotrophy and phototrophy. Mixotrophic dinoflagellates are a sub-type of planktonic dinoflagellates and are part of the phylum Dinoflagellata. They are flagellated eukaryotes that combine photoautotrophy when light is available, and heterotrophy via phagocytosis. Dinoflagellates are one of the most diverse and numerous species of phytoplankton, second to diatoms.

<i>Polykrikos</i> genus of unarmored pseudocolonial dinoflagellates

Polykrikos is one of the genera of family Polykrikaceae that includes athecate pseudocolony-forming dinoflagellates. Polykrikos are characterized by a sophisticated ballistic apparatus, named the nematocyst-taeniocyst complex, which allows species to prey on a variety of organisms. Polykrikos have been found to regulate algal blooms as they feed on toxic dinoflagellates. However, there is also some data available on Polykrikos being toxic to fish.

Nutrient cycling in the Columbia River Basin involves the transport of nutrients through the system, as well as transformations from among dissolved, solid, and gaseous phases, depending on the element. The elements that constitute important nutrient cycles include macronutrients such as nitrogen, silicate, phosphorus, and micronutrients, which are found in trace amounts, such as iron. Their cycling within a system is controlled by many biological, chemical, and physical processes.

Mesodinium may refer to:

References

  1. ↑ Gustafson, Daniel E.; Stoecker, Diane K.; Johnson, Matthew D.; Van Heukelem, William F.; Sneider, Kerri (2000). "Cryptophyte algae are robbed of their organelles by the marine ciliate Mesodinium rubrum". Nature. 405 (6790): 1049–1052. doi:10.1038/35016570. PMID   10890444.
  2. ↑ Ryther, John H. (1967). "Occurrence of red water off Peru". Nature. 214 (5095): 1318–1319. doi:10.1038/2141318a0.
  3. ↑ Johnson, William S.; Fylling, Dennis M. Allen (2012). Zooplankton of the Atlantic and Gulf coasts : a guide to their identification and ecology (2 ed.). Baltimore: Johns Hopkins University Press. p. 82. ISBN   978-1-421406183.
  4. ↑ Fehling, Johanna; Stoecker, Diane; Baldauf, Sandra L (2007). "Photosynthesis and the eukaryote tree of life". In Falkowski, Paul G.; Knoll, Andrew H. (eds.). Evolution of Primary Producers in the Sea. Amsterdam: Elsevier Academic Press. p. 97. ISBN   978-0-08-055051-0.
  5. 1 2 3 Johnson, Matthew D.; Tengs, Torstein; Oldach, David; Stoecker, Diane K. (2006). "Sequestration, performance, and functional control of cryptophyte plastids in the ciliate Myrionecta rubra (Ciliophora)". Journal of Phycology. 42 (6): 1235–1246. doi:10.1111/j.1529-8817.2006.00275.x.
  6. 1 2 Nowack, E. C. M.; Melkonian, M. (2010). "Endosymbiotic associations within protists". Philosophical Transactions of the Royal Society B: Biological Sciences. 365 (1541): 699–712. doi:10.1098/rstb.2009.0188. PMC   2817226 . PMID   20124339.
  7. ↑ Janson, Sven (2004). "Molecular evidence that plastids in the toxin-producing dinoflagellate genus Dinophysis originate from the free-living cryptophyte Teleaulax amphioxeia". Environmental Microbiology. 6 (10): 1102–1106. doi:10.1111/j.1462-2920.2004.00646.x. PMID   15344936.
  8. 1 2 Nishitani, G.; Nagai, S.; Baba, K.; Kiyokawa, S.; Kosaka, Y.; Miyamura, K.; Nishikawa, T.; Sakurada, K.; Shinada, A.; Kamiyama, T. (2010). "High-level congruence of Myrionecta rubra prey and Dinophysis species plastid identities as revealed by genetic analyses of isolates from Japanese coastal waters". Applied and Environmental Microbiology. 76 (9): 2791–2798. doi:10.1128/AEM.02566-09. PMC   2863437 . PMID   20305031.
  9. ↑ Hwang, C. Y.; Cho, K. D.; Yih, W.; Cho, B. C. (2009). "Maritalea myrionectae gen. nov., sp. nov., isolated from a culture of the marine ciliate Myrionecta rubra". International Journal of Systematic and Evolutionary Microbiology. 59 (3): 609–614. doi: 10.1099/ijs.0.002881-0 . PMID   19244448.
  10. ↑ Taylor, F. J. R.; Blackbourn, D. J.; Blackbourn, Janice (1971). "The red-water ciliate Mesodinium rubrum and its 'incomplete symbionts': A review including new ultrastructural observations". Journal of the Fisheries Research Board of Canada. 28 (3): 391–407. doi:10.1139/f71-052.
  11. ↑ Johnson, Matthew D.; Oldach, David; Delwiche, Charles F.; Stoecker, Diane K. (2007). "Retention of transcriptionally active cryptophyte nuclei by the ciliate Myrionecta rubra". Nature. 445 (7126): 426–428. doi:10.1038/nature05496. PMID   17251979.
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