For the first time, scientists have discovered something they didn’t think existed – an animal that can’t breathe oxygen – and obviously doesn’t need to.
Scientists have discovered something they did not think existed: an animal that can’t breathe oxygen, and obviously does not need to.
That animal is a parasite called Henneguya salminocola, distantly related to jellyfish . It lives in the muscles of salmon and trout, causing unsightly little white nodules known as “tapioca disease.”
The parasite has just 90 cells and is smaller than many of the cells in our bodies, but it has an extraordinary superpower – the ability to live without the machinery to turn oxygen into energy, researchers reported this week in the journal Proceedings of the National Academy of Sciences
“In a way, it changes our view.” of animals, “said senior author Dorothée Huchon, a zoology professor in the Faculty of Life Sciences and the Steinhardt Museum of Natural History at Tel Aviv University, who worked with collaborators in Israel, the US and Canada.
While many microbes have evolved the ability to live without oxygen, animals tend to be much more complex, with many different types of cells and tissues combined in one organism.
As far as scientists knew until now, all animals were powered by organelles called mitochondria, which convert sugar and oxygen into energy through a process called respiration, and have their own “mitochondrial” genes.
Andrew Roger, a Dalhousie University biology professor who was not involved in the study but was part of a team that discovered the first eukaryote (organism with complex cells) without mitochondria , said he was surprised by the discovery, but found the evidence convincing.
“There was a belief that All animals should have mitochondrial DNA and be able to do aerobic metabolism, “he said. “This one can’t. It changes the textbook account of what you see in the animal kingdom.”
However, he believes “it’s inevitable” that scientists will find more animals like Henneguya among those that have adapted to living in places with almost no oxygen, such as some parts of the ocean floor.
In fact, scientists have already proposed that one such group of animals called loriciferans can do that , and had some evidence that this was the case, although not as much or as detailed as for Henneguya.
Roger says animals can actually use an oxygen-free process to produce energy from sugar, but it’s far less efficient. He suspects this may be what Henneguya is doing.
Patrick Keeling, a biology professor at the University of British Columbia has also studied parasitic microbes that don’t breathe oxygen, but was not involved in the research.
He said it’s hard to prove that something does not exist, but Said Huchon and her team have done that.
He added that the ability to live without breathing oxygen has evolved many times among microbes in environments with little or no oxygen.
“In a way, it’s not surprising, “he said. “But it’s pretty cool that animals can do it too.”
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