• Log in with Facebook Log in with Twitter Log In with Google      Sign In    
  • Create Account
  LongeCity
              Advocacy & Research for Unlimited Lifespans

Photo

Not human but inspiring nonetheless: A marine parasite’s mitochondria lack DNA but still churn out energy

mitochondria algae amoebophyra ceratii dna

  • Please log in to reply
1 reply to this topic

#1 Engadin

  • Guest
  • 198 posts
  • 580
  • Location:Madrid
  • NO

Posted 26 April 2019 - 09:48 AM


The missing genetic material turned up in the microbe’s nucleus

 

042319_TI_mitochondria-dna_feat.jpg

PARASITE LIFE  Parasitic Amoebophyra ceratii, which surprisingly is missing its mitochondrial DNA, can infect an ocean alga called Alexandrium (healthy, left; infected, middle and right). The photosynthetic part of the alga is shown in red and the parasite’s cytoplasm in green. 

 

 

One parasite that feeds on algae is so voracious that it even stole its own mitochondria’s DNA.

Mitochondria — the energy-generating parts of cells — of the parasitic plankton   Amoebophyra ceratii   seem to have   transferred all of their DNA to the cell’s nucleus, researchers report April 24 in Science Advances. The discovery is the first time that scientists have found an oxygen-using organism with fully functional mitochondria that don’t have any mitochondrial DNA. (Some anaerobic organisms, which don’t need oxygen, and thus mitochondria, to survive, have also lost mitochondrial DNA.)

Mitochondria are thought to be bacteria that were captured by other cells and eventually became standard parts of eukaryotic cells — cells that encase their DNA and other parts in membranes. Mitochondria reside outside of the nucleus in a cell’s jellylike guts, the cytoplasm. Part of the settling-in process involved relocating some genes needed for mitochondria’s function to the nucleus of host cells. But most mitochondria kept at least a few genes. (Human mitochondria held on to 37 genes.)

Not so for   A. ceratii, Uwe John of the Alfred Wegener Institute in Bremerhaven, Germany, and colleagues discovered. The parasite, which infects algae that can cause toxic blooms, has two mitochondria during the free-living stage of its life cycle. Both are able to produce energy, the researchers found. But the team couldn’t spot any DNA inside the mitochondria.

 

A search of the DNA in the organism’s nucleus turned up genes needed for mitochondrial function there. The scientists conclude that all of the genes necessary to make working mitochondria were transferred to the nucleus, making it possible for the tiny energy factories to keep producing energy after they lost their DNA.

 

Source:   https://www.sciencen...a-no-dna-energy

 

 



#2 Engadin

  • Topic Starter
  • Guest
  • 198 posts
  • 580
  • Location:Madrid
  • NO

Posted 27 April 2019 - 02:29 PM

Life Extension Advocacy Foundation POV on this matter:

 

Mitochondria.jpg

 

 

A recent study has suggested that A.Ceratii, a parasite that feeds on small life forms, including the ones that form algal blooms, contains mitochondria that have no mitochondrial DNA, and at least some of this DNA is found in the parasite’s own genetic code. However, a few genes found in humans are missing and replaced with alternatives [1].

 

What are mitochondria?

Mitochondria, commonly referred to as the “powerhouses of the cell”, are essentially tiny chemical factories in our cells that turn fats and sugars into adenosine triphosphate (ATP), a form of chemical energy. One reason we need to breathe oxygen to live is to keep our mitochondria running.

 

Mitochondria produce free radicals as a byproduct of energy production, and damaged mitochondria secrete even more free radicals [2]. Free radicals bounce around the interior of the cell and can damage the mitochondrial DNA if they strike it. This can cause more widespread damage, leading to inflammation, cancer, cellular senescence, and other harmful effects [3].

 

 

Mitochondria are thought to have originally been individual organisms. According to the widely accepted endosymbiosis theory [4], early mitochondria were consumed by an ancestor of most complex life, including plants and animals, a long time ago. These useful mitochondria were not consumed by our cellular ancestors, and they were allowed to replicate as their host cells divided. Over time, their genetic code has moved to the nucleus, which contains the host cell’s DNA, in order to reduce the risk of damage; however, in humans, there is still an important exception of 13 genes that are vital for energy production.

 

What is special about this parasite?

Normally, the main vital function of mitochondria has five important structures that are coded for inside the mitochondrial genome: complexes 1, 2, 3, 4, and 5. In this parasite, however, complexes 2, 4, and 5 have been seen working without mitochondrial DNA, while complexes 1 and 3 have been replaced by other proteins with a similar function.

 

So far, no other lifeform has been seen with working mitochondria (containing each of these complexes or a similar protein) that do not possess mitochondrial DNA, making this parasite unique.

 

Why is this important?

This is the only natural example of mitochondria that have successfully had all of their vital DNA removed while remaining functional; mimicking this is the goal of MitoSENS, a SENS Research Foundation project that has been crowdfunded on Lifespan.io [5]. Moving our mitochondrial DNA to our nuclei is a proposed way to defeat mitochondrial dysfunction, which is one of the hallmarks of aging.

 

Complex 4 has been considered a significantly difficult complex to transfer through this method. However, since it and Complex 2 have been already transferred in this parasite, its genetic material may be useful for the development of a future gene therapy. MitoSENS has achieved the transference of Complex 5, which leaves only complexes 1 and 3 without any instances of being expressed without mitochondrial DNA in nature.

 

In a webinar with scientists from the SENS Research Foundation, it was revealed that at least one subunit-coding gene of complex 1 has been successfully transferred to the host cell genome in an as-of-yet unpublished paper, suggesting an optimistic outlook for the possibility of transferring more of these genes.

 

Source: https://www.leafscie...ia-without-dna/


Edited by Engadin, 27 April 2019 - 02:30 PM.


Click HERE to rent this BIOSCIENCE adspot to support LongeCity (this will replace the google ad above).




Also tagged with one or more of these keywords: mitochondria, algae, amoebophyra ceratii, dna

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users