๐ ๐ฃ๐๐ฅ๐ฅ๐ฒ๐๐ข๐ฌ๐ก ๐๐๐ง๐๐๐ซ ๐ข๐ง๐๐๐๐ญ๐ข๐ง๐ ๐ฌ๐๐ฅ๐ฆ๐จ๐ง? ๐๐ง๐ ๐ข๐ญ ๐๐จ๐๐ฌ๐ง’๐ญ ๐๐ซ๐๐๐ญ๐ก๐ ๐จ๐ฑ๐ฒ๐ ๐๐ง?
Today’s path rounds are on ๐ญ๐๐ฉ๐ข๐จ๐๐ ๐๐ข๐ฌ๐๐๐ฌ๐!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
Tapioca disease is a parasitic infection of salmon by the organism ๐๐๐ง๐ง๐๐ ๐ฎ๐ฒ๐ ๐ฌ๐๐ฅ๐ฆ๐ข๐ง๐ข๐๐จ๐ฅ๐. What is particularly interesting about this parasite is that it is actually a type of jellyfish! The infected areas of the fish form round, yellow-white cysts somewhat resembling tapioca. Yum!
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
Many species of fish are susceptible, however we most commonly see this disease in salmon.
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
Fish become infected as juveniles when they consume ๐ญ๐ฎ๐๐ข๐๐ข๐๐ข๐ ๐ฐ๐จ๐ซ๐ฆ๐ฌ carrying the parasite’s spores. The spores then travel through the circulatory system and reach the muscle, where they form cysts. When the fish dies, the cysts rupture and release spores into the water, continuing the life cycle.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
Thankfully, Henneguya doesn’t cause many issues for the fish. It also does not affect humans. However, it can affect the value of the fish as an edible item, since humans generally don’t enjoy eating spotty fish!
๐๐ญ ๐๐จ๐๐ฌ๐ง’๐ญ ๐๐ซ๐๐๐ญ๐ก๐ ๐จ๐ฑ๐ฒ๐ ๐๐ง?
Although this disease has been around for quite some time, researchers recently discovered that these Henneguya parasites don’t consume any oxygen! These parasitic cells lack ๐ฆ๐ข๐ญ๐จ๐๐ก๐จ๐ง๐๐ซ๐ข๐, the main cellular structure responsible for converting oxygen into energy.
Without mitochondria, it is impossible for the organism to use oxygen. There are other types of organisms, such as fungi and amoeba, who have similarly lost their mitochondria and rely exclusively on non-oxygen energy sources. However, this is the first time we have found an animal species that does not have mitochondria! This makes Henneguya the ๐จ๐ง๐ฅ๐ฒ ๐๐ง๐ข๐ฆ๐๐ฅ ๐ฌ๐ฉ๐๐๐ข๐๐ฌ we know of that doesn’t breathe.
๐๐จ๐ฐ ๐๐ข๐ ๐ ๐ฃ๐๐ฅ๐ฅ๐ฒ๐๐ข๐ฌ๐ก ๐๐๐๐จ๐ฆ๐ ๐ ๐ฉ๐๐ซ๐๐ฌ๐ข๐ญ๐?
Henneguya isn’t a traditional jellyfish, since it has lost a lot of the features we traditionally associate with jellyfish. We only know it is related to jellyfish based on genetic evaluation. In fact, so much of the genetic makeup of ๐ฆ๐ฒ๐ฑ๐จ๐ฌ๐ฉ๐จ๐ซ๐๐๐ง๐ฌ (the class Henneguya belongs to) has been lost that its genetic code is less than 5% the size of other jellyfish species.
The reason for the immense loss of genetic code in these species is unknown. Interestingly, most of the lost code is responsible for life as an independent organism, meaning that myxosporeans must now rely on other organisms to provide them their energy and nutrients.
One research group speculates that these organisms may have originated as a ๐ญ๐ซ๐๐ง๐ฌ๐ฆ๐ข๐ฌ๐ฌ๐ข๐๐ฅ๐ ๐ญ๐ฎ๐ฆ๐จ๐ซ. In this theory, the original tumor developed from a jellyfish and developed genetic mutations that allowed it to infect other animals. This is an ๐ข๐ง๐๐ซ๐๐๐ข๐๐ฅ๐ฒ ๐ซ๐๐ซ๐ feature among tumors, however it does happen!
After establishing a means of transmission between animals, the researchers speculate that the cancer ๐ข๐ง๐๐๐ฉ๐๐ง๐๐๐ง๐ญ๐ฅ๐ฒ ๐๐ฏ๐จ๐ฅ๐ฏ๐๐ ๐ฆ๐ฎ๐ฅ๐ญ๐ข๐๐๐ฅ๐ฅ๐ฎ๐ฅ๐๐ซ๐ข๐ญ๐ฒ. By doing so, they would essentially become their own species of animal, despite their cancerous origins.
More research is needed to determine the origin of myxosporeans. But if the ๐๐๐๐๐๐๐ (speciated by cancer development animals) ๐ก๐ฒ๐ฉ๐จ๐ญ๐ก๐๐ฌ๐ข๐ฌ holds true, that would be an absolutely crazy developmental process that we have never seen before!
๐๐ก๐จ๐ญ๐จ๐ฌ
1) Spores of Henneguya. The “eyes” that you see are actually stinger cells, harkening back to their jellyfish roots!
2-4) Tapioca cysts within salmon! Delicious.
๐๐จ๐ฎ๐ซ๐๐๐ฌ
A. Y. Panchin, V. V. Aleoshin, and Y. V. Panchin, โFrom tumors to species: a SCANDAL hypothesis,โ Biol Direct, vol. 14, p. 3, Jan. 2019, doi: 10.1186/s13062-019-0233-1.
A. Schmidt, โScientists Discover First-Known Non-Oxygen Breathing Animal | Blog | Nature | PBS,โ Nature.
Photo 1 ยฉ Stephen Douglas Atkinson.
Photos 2-3 ยฉ Wikimedia Commons contributors Flying Penguin and Michal Manas.
Photo 4 ยฉ US Geological Survey.
