Moontanman Posted April 27 Posted April 27 A marine algae and a nitrogen fixing bacteria have officially teamed up and the bacteria has become a new organelle inside a marine algae. The teaming up of nitrogen fixing bacteria and plants Is not a new (Azolla carolinensis) is one but the bacteria is just in a communal relationship with the plant but this bacteria has actually become an organelle inside the algae cells much like mitochondria or chloroplasts in other cells, this new organelle has been dubbed Nitroplast. https://newscenter.lbl.gov/2024/04/17/scientists-discover-first-nitrogen-fixing-organelle/ Quote After years of work, an international team found evidence that a once-independent nitrogen-fixing microbe has become a permanent resident within algae cells Quote Adapted from a release by Erin Malsbury at UC Santa Cruz Modern biology textbooks assert that only bacteria can take nitrogen from the atmosphere and convert it into a form that is usable for life. Plants that fix nitrogen, such as legumes, do so by harboring symbiotic bacteria in root nodules. But a recent discovery upends that rule. In two recent papers, an international team of scientists describe the first known nitrogen-fixing organelle within a eukaryotic cell. The organelle is the fourth example in history of primary endosymbiosis – the process by which a prokaryotic cell is engulfed by a eukaryotic cell and evolves beyond symbiosis into an organelle. “It’s very rare that organelles arise from these types of things,” said Tyler Coale, a postdoctoral scholar at UC Santa Cruz and first author on one of two recent papers. “The first time we think it happened, it gave rise to all complex life. Everything more complicated than a bacterial cell owes its existence to that event,” he said, referring to the origins of the mitochondria. “A billion years ago or so, it happened again with the chloroplast, and that gave us plants,” Coale said. The third known instance involves a microbe similar to a chloroplast. The organelle in this discovery has been named a nitroplast. I am remembering reading of another animal that has evolved something similar that allowed it live in anoxic water in the black sea. If I remember correctly it was a ctenophore, anyone remember this? 4
exchemist Posted April 27 Posted April 27 25 minutes ago, Moontanman said: A marine algae and a nitrogen fixing bacteria have officially teamed up and the bacteria has become a new organelle inside a marine algae. The teaming up of nitrogen fixing bacteria and plants Is not a new (Azolla carolinensis) is one but the bacteria is just in a communal relationship with the plant but this bacteria has actually become an organelle inside the algae cells much like mitochondria or chloroplasts in other cells, this new organelle has been dubbed Nitroplast. https://newscenter.lbl.gov/2024/04/17/scientists-discover-first-nitrogen-fixing-organelle/ Extremely interesting, thanks for posting this. It seems this may shed some light on very early evolutionary processes by which other organelles may have arisen, by being first endosymbionts and then getting integrated into the cell. I know next to nothing about this but I presume a key feature of the change would be the progressive migration of at least parts of the genetic coding needed for replication, from the endosymbiont to the nucleus of the host cell. I think I have read this is thought to have happened with mitochondria, which still retain some of their own DNA, separate from the cell nucleus. I see this work says that the template for some of the proteins the former endosymbiont needs is now in the cell nucleus, but a label is attached to them which gets them picked up by the "nitroplast". Perhaps investigation of this will help us understand how eukaryotes acquired other organelles in the long distant past. 1
exchemist Posted April 29 Posted April 29 On 4/27/2024 at 6:48 PM, Moontanman said: A marine algae and a nitrogen fixing bacteria have officially teamed up and the bacteria has become a new organelle inside a marine algae. The teaming up of nitrogen fixing bacteria and plants Is not a new (Azolla carolinensis) is one but the bacteria is just in a communal relationship with the plant but this bacteria has actually become an organelle inside the algae cells much like mitochondria or chloroplasts in other cells, this new organelle has been dubbed Nitroplast. https://newscenter.lbl.gov/2024/04/17/scientists-discover-first-nitrogen-fixing-organelle/ I am remembering reading of another animal that has evolved something similar that allowed it live in anoxic water in the black sea. If I remember correctly it was a ctenophore, anyone remember this? Actually this prompted me to wonder about where the "fixed", i.e. not molecular N2, nitrogen came from at the origin of life. It's impossible to construct terrestrial biochemistry without a source of this, whether from nitrites, nitrates or ammonia or something like that. Could be worth starting a thread on it.........I'll do some digging.
Moontanman Posted April 29 Author Posted April 29 1 hour ago, exchemist said: Actually this prompted me to wonder about where the "fixed", i.e. not molecular N2, nitrogen came from at the origin of life. It's impossible to construct terrestrial biochemistry without a source of this, whether from nitrites, nitrates or ammonia or something like that. Could be worth starting a thread on it.........I'll do some digging. Nitrous oxide from lightning ?
exchemist Posted April 29 Posted April 29 9 minutes ago, Moontanman said: Nitrous oxide from lightning ? Hardly enough for much, I'd have thought. But maybe just enough to get some biochemistry started. I suspect N availability would have been one of the key constraints at the beginning. But I may have found a good paper on this. Let me read it and start a new thread if it's what I'm after. 1
Moontanman Posted April 29 Author Posted April 29 5 minutes ago, exchemist said: Hardly enough for much, I'd have thought. But maybe just enough to get some biochemistry started. I suspect N availability would have been one of the key constraints at the beginning. But I may have found a good paper on this. Let me read it and start a new thread if it's what I'm after. Don't forget about ammonia, it is thought to have been present as well. 1
Sensei Posted April 29 Posted April 29 (edited) 17 minutes ago, exchemist said: Hardly enough for much, I'd have thought. But maybe just enough to get some biochemistry started. ..billions of years of lightning strikes make a difference.. https://en.wikipedia.org/wiki/NOx "Scientists Ott et al.[13] estimated that each flash of lightning on average in the several mid-latitude and subtropical thunderstorms studied turned 7 kg (15 lb) of nitrogen into chemically reactive NOx. With 1.4 billion lightning flashes per year, multiplied by 7 kilograms per lightning strike, they estimated the total amount of NOx produced by lightning per year is 8.6 million tonnes. However, NOx emissions resulting from fossil fuel combustion are estimated at 28.5 million tonnes.[14] " Edited April 29 by Sensei 1
exchemist Posted April 29 Posted April 29 12 minutes ago, Sensei said: ..billions of years of lightning strikes make a difference.. https://en.wikipedia.org/wiki/NOx "Scientists Ott et al.[13] estimated that each flash of lightning on average in the several mid-latitude and subtropical thunderstorms studied turned 7 kg (15 lb) of nitrogen into chemically reactive NOx. With 1.4 billion lightning flashes per year, multiplied by 7 kilograms per lightning strike, they estimated the total amount of NOx produced by lightning per year is 8.6 million tonnes. However, NOx emissions resulting from fossil fuel combustion are estimated at 28.5 million tonnes.[14] " OK, but telephone numbers like this don't tell us a great deal until put into context. What concentration of NOx is this thought to have generated? Especially in the marine environment where life is thought to have started. 1
CharonY Posted April 29 Posted April 29 47 minutes ago, Moontanman said: Don't forget about ammonia, it is thought to have been present as well. I may be wrong but I think the general assumption is that it is the most likely nitrogen source used by early life.
Moontanman Posted April 29 Author Posted April 29 1 minute ago, CharonY said: I may be wrong but I think the general assumption is that it is the most likely nitrogen source used by early life. Ammonia is still an important food source for life, at least in aquatic captives. If not for bacteria that oxidize ammonia it would be very difficult to keep aquariums... 😁
exchemist Posted April 29 Posted April 29 20 minutes ago, Moontanman said: Ammonia is still an important food source for life, at least in aquatic captives. If not for bacteria that oxidize ammonia it would be very difficult to keep aquariums... 😁 OK, I've now started a thread on the evolution of nitrogenase, in the Evolution section of Biology. I knew nothing about this at all until a few days ago. 😀
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