Margalefidinium polykrikoides: Difference between revisions
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==Cell Structure, Metabolism and Life Cycle== | ==Cell Structure, Metabolism and Life Cycle== | ||
''M. Polykrikoides'' utilizes both organic phosphorus and nitrogen compounds but prefers NH4+ rather than NO2− and NO3- , during periods of high NH4+ concentration it has the highest growth rate (Liu et al 2021). ''M. Polykrikoides'' is largely photosynthetic but during periods of nutrient scarcity, the dinoflagellate also feeds on planktonic prey to sustain the population (Aquino-Cruz et al 2020). Reactive Oxygen Species (ROS) are created during various metabolic and biochemical processes, but is mostly found in chloroplasts, peroxisomes, and mitochondria (Aquino-Cruz et al 2020). | |||
The lifecycle consists of a few distinct stages: resting cyst, vegetative, temporary cyst, gametes, planozygote, chains depending on nutrient availability and water temperatures (Tang and Gobler 2012). From the resting cyst, germination occurs. During the germination process, reorganization of cell contents can be observed. Then, the protoplasm transforms into a motile cell with both transverse and longitudinal flagella and the motile cell emerges from the resting cyst (Li et al 2020, Tang and Gobler 2012). The opposite was also observed, where the reorganized cell contents are released via amoeboid motion and then it transforms into a motile, “germling” cell (Li et al 2020). Once in the motile stage, a germling cell can reproduce, asexually to form vegetative cells, sexually with punitive gametes, or form chains (Liu et al 2020). The chains of 2+ cells are used to enhance motility and maintain surface positions in warm, low-viscosity water (Griffith et al 2019). | |||
Four major points to the lifecycle were extracted from the paper by Li et al, as follows (2020). The resting cyst has a distinct germination process where a mature, motile cell is visible inside the cyst before emergence. The chain forming cells can produce temporary cysts can reproduce without asexual or sexual reproduction. Gamete fusion produces a planozygote which can be divided into single cells. ''M. Polykrikoides'' sexuality is considered homothallic mating behavior. | |||
==Ecology and Pathogenesis== | ==Ecology and Pathogenesis== | ||
Revision as of 17:03, 7 November 2022
Classification
Higher Order Taxa
Eukaryota; Sar; Alveolata; Dinophyceae; Gymnodiniales; Gymnodiniaceae
Species
Margalefidinium polykrikoides
Previously known as Cochlodinium polykrikoides.
Description and Significance
M. polykrikoides is a cyst-forming, photosynthetic, and mixotrophic marine dinoflagellate (Lopez-Cortes et al 2019). The genus Cochlodinium was established in the late nineteenth century, and C. polykrikoides was recently reassigned to the genus Margalefidinium (Lopez-Cortes et al 2019). Since they are unicellular eukaryotes, they have a small cell size of 10-100µm and an extremely large genome (Hong et al 2016).
Genome Structure
M. Polykrikoides is ranked as the 5th largest among dinoflagellates, with a nuclear genome size estimated between 100.97 Gb -110.54 Gb via flow cytometry (Hong et al 2016). Increased amounts of gene copies, repetitive sequences, and multiple noncoding DNA elements (pseudogenes etc.) may be responsible for this extremely large genome as well as their complex physiological and metabolic characteristics (Hong et al 2016).
Cell Structure, Metabolism and Life Cycle
M. Polykrikoides utilizes both organic phosphorus and nitrogen compounds but prefers NH4+ rather than NO2− and NO3- , during periods of high NH4+ concentration it has the highest growth rate (Liu et al 2021). M. Polykrikoides is largely photosynthetic but during periods of nutrient scarcity, the dinoflagellate also feeds on planktonic prey to sustain the population (Aquino-Cruz et al 2020). Reactive Oxygen Species (ROS) are created during various metabolic and biochemical processes, but is mostly found in chloroplasts, peroxisomes, and mitochondria (Aquino-Cruz et al 2020).
The lifecycle consists of a few distinct stages: resting cyst, vegetative, temporary cyst, gametes, planozygote, chains depending on nutrient availability and water temperatures (Tang and Gobler 2012). From the resting cyst, germination occurs. During the germination process, reorganization of cell contents can be observed. Then, the protoplasm transforms into a motile cell with both transverse and longitudinal flagella and the motile cell emerges from the resting cyst (Li et al 2020, Tang and Gobler 2012). The opposite was also observed, where the reorganized cell contents are released via amoeboid motion and then it transforms into a motile, “germling” cell (Li et al 2020). Once in the motile stage, a germling cell can reproduce, asexually to form vegetative cells, sexually with punitive gametes, or form chains (Liu et al 2020). The chains of 2+ cells are used to enhance motility and maintain surface positions in warm, low-viscosity water (Griffith et al 2019).
Four major points to the lifecycle were extracted from the paper by Li et al, as follows (2020). The resting cyst has a distinct germination process where a mature, motile cell is visible inside the cyst before emergence. The chain forming cells can produce temporary cysts can reproduce without asexual or sexual reproduction. Gamete fusion produces a planozygote which can be divided into single cells. M. Polykrikoides sexuality is considered homothallic mating behavior.
Ecology and Pathogenesis
Habitat; symbiosis; biogeochemical significance; contributions to environment.
If relevant, how does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
References
Author
Page authored by Nina McVay, student of Prof. Bradley Tolar at UNC Wilmington.
