A Multicellular Organism That Doesn't Breathe Oxygen

[Recusant]

Its ancestors breathed, but it has dispensed with directly using oxygen. Henneguya salminicola is the first known instance of this type of arrangement.

"Henneguya salminicola: Microscopic parasite has no mitochondrial DNA" | Phys.org

Light microscope image of spores of the parasitic cnidarian Henneguya salminicola,
from Chinook salmon.
Image credit: Stephen Douglas Atkinson

An international team of researchers has found a multicellular animal with no mitochondrial DNA, making it the only known animal to exist without the need to breathe oxygen. In their paper published in Proceedings of the National Academy of Sciences, the group describes their study of Henneguya salminicola, a microscopic, parasitic member of the group Myxozoa and its unique physiology.

One of the common characteristics of all multicellular animals on Earth is mitochondrial respiration—the process by which oxygen is used to generate adenosine triphosphate—the fuel used to power cellular processes. The process takes place in mitochondria, which has both its own genome and the main genome found in the rest of the body's cells. But now, there is a known exception: Henneguya salminicola.

H. salminicola is a microscopic parasite that infects salmon. When the host dies, spores are released that are consumed by worms, which can also serve as hosts for the parasite. When salmon eat the worms, they become infected as the parasite moves into their muscles. They can be seen by fishermen as white, oozing bubbles, which is why salmon with H. salminicola infections are sometimes said to have tapioca disease.

[Continues . . .]

* * *

"Scientists Find The First-Ever Animal That Doesn't Need Oxygen to Survive" | ScienceAlert

Image credit: Stephen Douglas Atkinson

Scientists have just discovered that a jellyfish-like parasite doesn't have a mitochondrial genome - the first multicellular organism known to have this absence. That means it doesn't breathe; in fact, it lives its life completely free of oxygen dependency.

This discovery isn't just changing our understanding of how life can work here on Earth - it could also have implications for the search for extraterrestrial life.

Life started to develop the ability to metabolise oxygen - that is, respirate - sometime over 1.45 billion years ago. A larger archaeon engulfed a smaller bacterium, and somehow the bacterium's new home was beneficial to both parties, and the two stayed together.

That symbiotic relationship resulted in the two organisms evolving together, and eventually those bacteria ensconced within became organelles called mitochondria. Every cell in your body except red blood cells has large numbers of mitochondria, and these are essential for the respiration process.

They break down oxygen to produce a molecule called adenosine triphosphate, which multicellular organisms use to power cellular processes.

We know there are adaptations that allow some organisms to thrive in low-oxygen, or hypoxic, conditions. Some single-celled organisms have evolved mitochondria-related organelles for anaerobic metabolism; but the possibility of exclusively anaerobic multicellular organisms has been the subject of some scientific debate.

That is, until a team of researchers led by Dayana Yahalomi of Tel Aviv University in Israel decided to take another look at a common salmon parasite called Henneguya salminicola.

It's a cnidarian, belonging to the same phylum as corals, jellyfish and anemones. Although the cysts it creates in the fish's flesh are unsightly, the parasites are not harmful, and will live with the salmon for its entire life cycle.

Tucked away inside its host, the tiny cnidarian can survive quite hypoxic conditions. But exactly how it does so is difficult to know without looking at the creature's DNA - so that's what the researchers did.

They used deep sequencing and fluorescence microscopy to conduct a close study of H. salminicola, and found that it has lost its mitochondrial genome. In addition, it's also lost the capacity for aerobic respiration, and almost all of the nuclear genes involved in transcribing and replicating mitochondria.

[. . .]

Exactly how it survives is still something of a mystery. It could be leeching adenosine triphosphate from its host, but that's yet to be determined.

But the loss is pretty consistent with an overall trend in these creatures - one of genetic simplification. Over many, many years, they have basically devolved from a free-living jellyfish ancestor into the much more simple parasite we see today.

[Continues . . .]

* * *

"Discovered: Henneguya Salminicola, The Only Animal On Earth That Doesn't Breathe" | Science 2.0

Scientists have discovered a non-oxygen breathing animal, a tiny, less than 10-celled parasite named Henneguya salminicola which lives in salmon muscle.

As it evolved, the animal, a myxozoan relative of jellyfish and corals, gave up breathing and consuming oxygen to produce energy.

Aerobic respiration is a major source of energy but organisms like fungi, amoebas or ciliate lineages in anaerobic environments have lost the ability to breathe over time. This is the first discovery of an animal that gave up this critical pathway, possibly because the parasite happens to live in an anaerobic environment.

[Continues . . .]

There is a link to the abstract in the last paragraph above, but the full paper is behind a paywall.

[Kusa]

I want to have this ability.

[Recusant]

Would you be willing to live in a fish cyst to obtain it?

[Kusa]

Depends on what the pay is.

[Recusant]

 

[Dark Lightning]

Depends on what the pay is.

All the salmon you can eat.