Microbe Matters | Learn Science at Scitable

May 25, 2016 | By:  Kriti Lall

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Mitochondria: An Essential Cellular Organelle?

The mitochondria is a cell organelle that is known as the “powerhouse of the cell,” known to be essential to every single living eukaryote. But is it really that essential?


Scientists at the Charles University in Prague recently sequenced the genome of the gut microbe, called Monocercomonoides sp. (shown on the left), isolated from a researcher’s pet chinchilla. They expected to find some kind of vestigial mitochondrion, but instead, they didn’t find evidence that it made any mitochondrial proteins.

So far, that’s unheard of.

Anna Karnkowska, an author in the study, says, “In low-oxygen environments, eukaryotes often possess a reduced form of the mitochondrion, but it was believed that some of the mitochondrial functions are so essential that these organelles are indispensable for their life. We have characterized a eukaryotic microbe which indeed possesses no mitochondrion at all.”


She continued, “This amazing organism is a striking example of a cell which refuses to adhere to the standard cell biology textbook, and we believe there may be many more similar examples in the so far hidden diversity in the world of microbial eukaryotes.”

This discovery comes after many years of researchers trying to find organisms without mitochondria. For instance, previously researchers thought they had succeeded in finding a microbe without the organelle when they found the Giardia, a human gut parasite. However, Giardia still had vestigial mitochondria.

Although Monocercomonoides sp. lacks a mitochondrion, researchers found that it had a system called an SUF, which stands for a cytosolic sulfur mobilization system, which is originally of prokaryotic origin. They believe the system essentially substitutes for a mitochondrion in the organism.

Their next steps include learning more about how Monocercomonoides sp. functions, as well as investigating how the mitochondrion was lost and the SUF system was gained in this organism.

References

Karnkowska, A., et al. A Eukaryote without a Mitochondrial Organelle. Cell. 26. 1274-1284 (2016).

Khan, A. How is this Possible? Mysterious Mitochondria is Missing Mitochondria. Sci-Tech Today (2016).

Scientists find First-Ever Microbe Without Mitochondria. Futurism (2016).

Photo Credits

Mitochondrion (via Wikimedia)

Monocercomonoides sp. (ScienceDaily, via Dr. Naoji Yubuki)

https://www.nature.com/scitable/blog/microbe-matters

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