Blastodinium
Classification
Higher Order Taxa
Domain:Eukaryota; Phylum:Dinoflagellata; Class:Blastodiniphyceae; Order:Blastodiniales; Family:Blastodinidae; Genus:Blastodinium
Genus
Blastodinium
Description and Significance
This genus contains cryptic species. All species in this genus have very similar morphological features, only differing slightly in their genomes. These species are obligate parasites, in which they must live inside a host in order to complete their life cycles. This genus will inhabit the gut of marine copepods, a group of small crustaceans typically 1-2mm in length. These parasites can grow to be a few hundred μm in length while inside the host.
These parasites are found in habits occupied by their copepods hosts-across the globe. However, these parasites are found in greater abundances in low nutrient, oligotrophic marine waters closer to the equator. The parasites found in this habitat have a greater chance of possessing chloroplasts, however, those found in colder waters near the poles of the planet are often found having no chloroplasts.
Life Cycle
The complete life cycle of species in the genus Blastodinium is unknown due to lack of experimental research. The life cycle stages during and after parasitism are known, however. This stage of the life cycle consists of the dinospore of the organism being ingested by the host and it becoming lodged in the copepod's gut. This dinospore grows into a trophocyte while inside the host. The trophocyte then divides into a secondary trophocyte and a gonocyte. The seconary trophocyte can divide into succeeding trophocytes and gonocytes, while the gonocyte will form sporocytes. Through dispersal mechanisms, the sporocytes release spores from the host, resulting in spores able to be ingested by more hosts.
Cell Structure and Metabolism
Ecology and Pathogenesis
The parasitic species in the genus Blastodinium have the ability to reverse the sex of male copepods and cause female copepods to become sterile. It is hypothesized that the size of the parasite inside the host can cause the loss of physiological reproductive function in females due to the pressure on its organs. The sex reversal mechanism that occurs in male copepods remains inconclusive due to lack of research on the subject. These effects on the male and female copepods would have a direct impact on copepod populations. The copepod population would be reduced due to the inability to mate between copepods. This would impact the higher trophic levels. This is just one ecological impact these parasites have.
Another impact is the effect on the biogeochemical cycle.
References
Author
Page authored by _____, student of Prof. Jay Lennon at IndianaUniversity.
