ARTICLE| VOLUME 26, ISSUE 10, P1274-1284, MAY 23, 2016

A Eukaryote without a Mitochondrial Organelle

https://www.cell.com/current-biology/abstract/S0960-9822(16)30263-9
Highlights

 Monocercomonoides sp. is a eukaryotic microorganism with no mitochondriaThe complete absence of mitochondria is a secondary loss, not an ancestral featureThe essential mitochondrial ISC pathway was replaced by a bacterial SUF system

Summary

The presence of mitochondria and related organelles in every studied eukaryote supports the view that mitochondria are essential cellular components. Here, we report the genome sequence of a microbial eukaryote, the oxymonadMonocercomonoides sp., which revealed that this organism lacks all hallmark mitochondrial proteins. Crucially, the mitochondrial iron-sulfur cluster assembly pathway, thought to be conserved in virtually all eukaryotic cells, has been replaced by a cytosolic sulfur mobilization system (SUF) acquired by lateral gene transfer from bacteria.

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So what are the implications of this then?

Bubblecar said:

So what are the implications of this then?

There are more things on heaven and earth, Horatio, than are dreamt of in your philosophy…etc.

will this go the way of the arsenic poisoning

http://www.abc.net.au/news/2012-07-09/scientists-disprove-arsenic-life-form-claim/4118444

Bubblecar said:

So what are the implications of this then?

Well it’s certainly a turn up for the books.

Broadly, cellular life is divided into archaea, bacteria, and eukaryota. The Eukaryotes are the only form of life with a proper cell nucleus, and they feature more internal complexity than other kinds of life. Eukaryotes are typically much larger than bacteria or archaea, and also are the only kind of life to be multicellular (though some eukaryotes are unicellular, still).

Mitochondria play the crucial role of converting sugars to adenosine triphosphate (ATP) which acts as the fast energy source for most kinds of cellular activity. Mitochondria have their own DNA, and even when existing within the cells of eukaryotes, undergo asexual reproduction. Whereas you or I have genetic family trees that difurcate at each generation, mitochondria are more like bacteria in this regard: they divide into identical copies, (barring mutations). It is widely thought that mitochondria are descended from bacteria that had a symbiotic relationship with eukaryotes, eventually becoming a necessary, intrinsic part of the functioning of the eukaryotic cells.

So finding a eukaryotic life form that has done away with them is a surprise. It’s come up with a completely different mechanism for obtaining energy from its environment.

It’s such a revolutionary change that, assuming this critter has descendants, biologists of the distant future might look back on this thing as the first member of a new domain of life.

SCIENCE said:

will this go the way of the arsenic poisoning

Fair question. Let’s not start flagellating each others’ thecae just yet.

But it is a bit different. It’s a bit hard to be mistaken about the complete absence of organelles.

dv said:

Bubblecar said:

So what are the implications of this then?

Well it’s certainly a turn up for the books.

Broadly, cellular life is divided into archaea, bacteria, and eukaryota. The Eukaryotes are the only form of life with a proper cell nucleus, and they feature more internal complexity than other kinds of life. Eukaryotes are typically much larger than bacteria or archaea, and also are the only kind of life to be multicellular (though some eukaryotes are unicellular, still).

Mitochondria play the crucial role of converting sugars to adenosine triphosphate (ATP) which acts as the fast energy source for most kinds of cellular activity. Mitochondria have their own DNA, and even when existing within the cells of eukaryotes, undergo asexual reproduction. Whereas you or I have genetic family trees that difurcate at each generation, mitochondria are more like bacteria in this regard: they divide into identical copies, (barring mutations). It is widely thought that mitochondria are descended from bacteria that had a symbiotic relationship with eukaryotes, eventually becoming a necessary, intrinsic part of the functioning of the eukaryotic cells.

So finding a eukaryotic life form that has done away with them is a surprise. It’s come up with a completely different mechanism for obtaining energy from its environment.

It’s such a revolutionary change that, assuming this critter has descendants, biologists of the distant future might look back on this thing as the first member of a new domain of life.

Ta, interesting.

> Mitochondria play the crucial role of converting sugars to adenosine triphosphate (ATP) which acts as the fast energy source for most kinds of cellular activity.

Yes.

So why did Monocercomonoides get rid of them?