by Piter Kehoma Boll
While looking for flatfish you may eventually find one with some grotesque growth on the body, like the one in the picture below:
This sort of tumor is called xenoma and, in flatfish, is caused by a microscopical and parasitic fungus named Glugea stephani, or the flounder glugea.
The flounder glugea is part of a group of fungi called Microsporidia that until recently were classified as protists. They are unicellular and parasite other organisms, especially crustaceans and fish.
Once inside a flatfish, the flounder glugea enters an intestinal cell and starts to develop. They induce the host cell to increase in size and may give rise to the xenomas, which are the most extreme stage in the development of the disease. The proliferating and active stage of the glugea are free in the cytoplasm of the host cell, but they may change into a spore-like form called sporoblast that remains inside a vacuole.
Fortunately most infections are mild and do not compromise the fish health, at least not very much…
– – –
Takvorian, P. M.; Cali, A. (1983). Appendages associated with Glugea stephani, a microscporidian found in flounder. Journal of Protozoology, 30(2): 251-256.
Wikipedia. Xenoma. Available at: < https://en.wikipedia.org/wiki/Xenoma >. Access on September 17, 2016.
– – –
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.