''Mesodinium chamaeleon'' is a

ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a differen ...

of the genus ''

Mesodinium Mesodinium is a genus of ciliates that are widely distributed and are abundant in marine and brackish waters. Currently, six marine species of ''Mesodinium'' have been described and grouped by nutritional mode: plastidic (''M. chamaeleon'', ''M ...

''. It is known for being able to consume and maintain

algae Algae ( , ; : alga ) are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from ...

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 A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but ...

into an

autotroph An autotroph or primary producer is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide,Morris, J. et al. (2019). "Biology: How Life Works", ...

. The species was discovered in January 2012 outside the coast of

Nivå Nivå is a town with a population of 7,997 (1 January 2022)Øjvind Moestrup. In contrast to certain other species of the genus, ''Mesodinium chamaeleon'' can be maintained in culture for short periods only. It captures and ingests

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 the ...

s including

cryptomonad The cryptomonads (or cryptophytes) 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 anterio ...

s. The prey is ingested very rapidly into a

food vacuole The food vacuole, or digestive vacuole, is an organelle found in simple eukaryotes such as protists. This organelle is essentially a lysosome. During the stage of the symbiont parasites' lifecycle where it resides within a human (or other mammalia ...

without the cryptomonad flagella being shed and the

trichocyst A trichocyst is an organelle found in certain ciliates and dinoflagellates. A trichocyst can be found in tetrahymena ''Tetrahymena'', a unicellular eukaryote, is a genus of free-living ciliates. The genus Tetrahymena is the most widely studie ...

s being discharged. The individual food vacuoles subsequently serve as photosynthetic units, each containing the cryptomonad chloroplast, a

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom * Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...

, and some mitochondria. The ingested cells are eventually digested. This type of symbiosis differs from other plastid-bearing ''

'' spp. Among the strains that belong to ''

Mesodinium rubrum ''Mesodinium rubrum'' (or ''Myrionecta rubra'') is a species of ciliates. 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 i ...

'', they are known for causing

red tide A harmful algal bloom (HAB) (or excessive algae growth) is an algal bloom that causes negative impacts to other organisms by production of natural phycotoxin, algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are ...

s in many

coast The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in n ...

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syst ...

s. Although one of them denominated as ''M. rubrum'' is known as a non-toxic species, ciliate blooms can be potentially

harmful Harmful is a rock band from Frankfurt, Germany, founded in 1992 and frequently compared to early Helmet and more occasionally to Blackmail.sefor an overview of reviewer opinions The band has released eight albums to date, the first two and the la ...

to aquaculture industries. ''M. rubrum'' performs photosynthesis by sequestering the nucleus of its cryptophytic prey, in order to keep the plastids and other stolen organelles. By this, the retained ingested cryptomonad cells remain almost intact. The food strategy of ''M. chamaeleon'' appears to be intermediate between

heterotrophic A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but ...

species, such as ''

Mesodinium pulex Mesodinium is a genus of ciliates that are widely distributed and are abundant in marine and brackish waters. Currently, six marine species of ''Mesodinium'' have been described and grouped by nutritional mode: plastidic (''M. chamaeleon'', ''M ...

'' and ''

Mesodinium pupula Mesodinium is a genus of ciliates that are widely distributed and are abundant in marine and brackish waters. Currently, six marine species of ''Mesodinium'' have been described and grouped by nutritional mode: plastidic (''M. chamaeleon'', ''M ...

'', and species with red

endosymbionts, such as ''Mesodinium rubrum''.

References

Moeller, Holly, "Preferential Plastid Retention by the Acquired Phototroph Mesodinium chamaeleon", 2018-03, Vol.65 (2), p.148-158 * * * {{Taxonbar, from=Q6821479 Mesodinium Endosymbiotic events Protists described in 2012 Ciliate species