We had an article some 4 years ago about Monocercomonoides, single-celled flagellates that live in the digestive tracts of various animals. These were the first Eukaryotes ever found without mitochondria. (Eukaryotes are critters with a proper nucleus in the cell, which distinguishes them from bacteria and archaea.)

https://tokyo3.org/forums/holiday/?main=https%3A//tokyo3.org/forums/holiday/topics/10171/

We had a bit of a discussion back then about why this was noteworthy.

It has been announced recently that Henneguya salminicola, a small Cnidarian, also has not mitochondrial genome, though it appears to have structures that would normally be considered mitochondiral organelles. (The Cnidarians are a group of marine animals that include jellyfish, sea fans, corals etc.)

These are actual animals (multicellular metazoans), and this marks the first time any animal has been found without the means for aerobic respiration.

Henneguya salminicola are less than a millimetre in length are are parasites found in salmon intestines.

https://www.pnas.org/content/early/2020/02/18/1909907117

Mitochondrial respiration is an ancient characteristic of eukaryotes. However, it was lost independently in multiple eukaryotic lineages as part of adaptations to an anaerobic lifestyle. We show that a similar adaptation occurred in a member of the Myxozoa, a large group of microscopic parasitic animals that are closely related to jellyfish and hydroids. Using deep sequencing approaches supported by microscopic observations, we present evidence that an animal has lost its mitochondrial genome. The myxozoan cells retain structures deemed mitochondrion-related organelles, but have lost genes related to aerobic respiration and mitochondrial genome replication. Our discovery shows that aerobic respiration, one of the most important metabolic pathways, is not ubiquitous among animals.

dv said:

We had an article some 4 years ago about Monocercomonoides, single-celled flagellates that live in the digestive tracts of various animals. These were the first Eukaryotes ever found without mitochondria. (Eukaryotes are critters with a proper nucleus in the cell, which distinguishes them from bacteria and archaea.)

https://tokyo3.org/forums/holiday/?main=https%3A//tokyo3.org/forums/holiday/topics/10171/

We had a bit of a discussion back then about why this was noteworthy.

It has been announced recently that Henneguya salminicola, a small Cnidarian, also has not mitochondrial genome, though it appears to have structures that would normally be considered mitochondiral organelles. (The Cnidarians are a group of marine animals that include jellyfish, sea fans, corals etc.)

These are actual animals (multicellular metazoans), and this marks the first time any animal has been found without the means for aerobic respiration.

Henneguya salminicola are less than a millimetre in length are are parasites found in salmon intestines.

https://www.pnas.org/content/early/2020/02/18/1909907117

Mitochondrial respiration is an ancient characteristic of eukaryotes. However, it was lost independently in multiple eukaryotic lineages as part of adaptations to an anaerobic lifestyle. We show that a similar adaptation occurred in a member of the Myxozoa, a large group of microscopic parasitic animals that are closely related to jellyfish and hydroids. Using deep sequencing approaches supported by microscopic observations, we present evidence that an animal has lost its mitochondrial genome. The myxozoan cells retain structures deemed mitochondrion-related organelles, but have lost genes related to aerobic respiration and mitochondrial genome replication. Our discovery shows that aerobic respiration, one of the most important metabolic pathways, is not ubiquitous among animals.

How about that!

Thanks.

Michael V said:

dv said:

We had an article some 4 years ago about Monocercomonoides, single-celled flagellates that live in the digestive tracts of various animals. These were the first Eukaryotes ever found without mitochondria. (Eukaryotes are critters with a proper nucleus in the cell, which distinguishes them from bacteria and archaea.)

https://tokyo3.org/forums/holiday/?main=https%3A//tokyo3.org/forums/holiday/topics/10171/

We had a bit of a discussion back then about why this was noteworthy.

It has been announced recently that Henneguya salminicola, a small Cnidarian, also has not mitochondrial genome, though it appears to have structures that would normally be considered mitochondiral organelles. (The Cnidarians are a group of marine animals that include jellyfish, sea fans, corals etc.)

These are actual animals (multicellular metazoans), and this marks the first time any animal has been found without the means for aerobic respiration.

Henneguya salminicola are less than a millimetre in length are are parasites found in salmon intestines.

https://www.pnas.org/content/early/2020/02/18/1909907117

Mitochondrial respiration is an ancient characteristic of eukaryotes. However, it was lost independently in multiple eukaryotic lineages as part of adaptations to an anaerobic lifestyle. We show that a similar adaptation occurred in a member of the Myxozoa, a large group of microscopic parasitic animals that are closely related to jellyfish and hydroids. Using deep sequencing approaches supported by microscopic observations, we present evidence that an animal has lost its mitochondrial genome. The myxozoan cells retain structures deemed mitochondrion-related organelles, but have lost genes related to aerobic respiration and mitochondrial genome replication. Our discovery shows that aerobic respiration, one of the most important metabolic pathways, is not ubiquitous among animals.

How about that!

Thanks.

It is awesome.

roughbarked said:

Michael V said:

dv said:

We had an article some 4 years ago about Monocercomonoides, single-celled flagellates that live in the digestive tracts of various animals. These were the first Eukaryotes ever found without mitochondria. (Eukaryotes are critters with a proper nucleus in the cell, which distinguishes them from bacteria and archaea.)

https://tokyo3.org/forums/holiday/?main=https%3A//tokyo3.org/forums/holiday/topics/10171/

We had a bit of a discussion back then about why this was noteworthy.

It has been announced recently that Henneguya salminicola, a small Cnidarian, also has not mitochondrial genome, though it appears to have structures that would normally be considered mitochondiral organelles. (The Cnidarians are a group of marine animals that include jellyfish, sea fans, corals etc.)

These are actual animals (multicellular metazoans), and this marks the first time any animal has been found without the means for aerobic respiration.

Henneguya salminicola are less than a millimetre in length are are parasites found in salmon intestines.

https://www.pnas.org/content/early/2020/02/18/1909907117

Mitochondrial respiration is an ancient characteristic of eukaryotes. However, it was lost independently in multiple eukaryotic lineages as part of adaptations to an anaerobic lifestyle. We show that a similar adaptation occurred in a member of the Myxozoa, a large group of microscopic parasitic animals that are closely related to jellyfish and hydroids. Using deep sequencing approaches supported by microscopic observations, we present evidence that an animal has lost its mitochondrial genome. The myxozoan cells retain structures deemed mitochondrion-related organelles, but have lost genes related to aerobic respiration and mitochondrial genome replication. Our discovery shows that aerobic respiration, one of the most important metabolic pathways, is not ubiquitous among animals.

How about that!

Thanks.

It is awesome.

> Henneguya salminicola, a small Cnidarian, also has not mitochondrial genome, though it appears to have structures that would normally be considered mitochondrial organelles.

Startling, but far from impossible. Mitochondria don’t actually have to have their own genome, it could be shuffled in with nuclear material. It’s just that most eukaryotes find it convenient to have a separate mitochondrial genome to generate oodles of the things and so get energy for running the cells faster. But if the organism doesn’t need a lot of energy then it can dispense with the mitochondrial genome addition, I suppose.

mollwollfumble said:

roughbarked said:

Michael V said:

How about that!

Thanks.

It is awesome.

> Henneguya salminicola, a small Cnidarian, also has not mitochondrial genome, though it appears to have structures that would normally be considered mitochondrial organelles.

Startling, but far from impossible. Mitochondria don’t actually have to have their own genome, it could be shuffled in with nuclear material. It’s just that most eukaryotes find it convenient to have a separate mitochondrial genome to generate oodles of the things and so get energy for running the cells faster. But if the organism doesn’t need a lot of energy then it can dispense with the mitochondrial genome addition, I suppose.

Might need to expand the possibilities of extraterrestrial lifeforms.

PermeateFree said:

mollwollfumble said:

roughbarked said:

It is awesome.

> Henneguya salminicola, a small Cnidarian, also has not mitochondrial genome, though it appears to have structures that would normally be considered mitochondrial organelles.

Startling, but far from impossible. Mitochondria don’t actually have to have their own genome, it could be shuffled in with nuclear material. It’s just that most eukaryotes find it convenient to have a separate mitochondrial genome to generate oodles of the things and so get energy for running the cells faster. But if the organism doesn’t need a lot of energy then it can dispense with the mitochondrial genome addition, I suppose.

Might need to expand the possibilities of extraterrestrial lifeforms.

Only it they’re parasites. Just kidding.

Any oxidising element can substitute for oxygen. On Earth for instance, sulfur may have been used for oxidation before oxygen was used. I ought to check that up. Aquifex may be one of the basal bacteria, what does it use?

“Aquifex spp. are rod-shaped bacteria with a length of 2 to 6 µm and a diameter of around 0.5 µm. They are non-sporeforming, Gram negative autotrophs. Aquifex means water-maker in Latin, and refers to the fact that its method of respiration creates water. Aquifex tend to form cell aggregates composed of up to 100 individual cells. Aquifex spp. are thermophilic and often grow near underwater volcanoes or hot springs. A. aeolicus requires oxygen to survive, but can grow in levels of oxygen as low as 7.5 ppm. A. pyrophilus can even grow anaerobically by reducing nitrogen instead of oxygen.”

Hmm. Cell wall already very complicated. Perhaps not Aquifex then.