Vishwam Sankaran
THE INDEPENDENT
Tue 8 October 2024
Comb jelly in seawater tank (Jokura et al., Current Biology (2024))
Tue 8 October 2024
Comb jelly in seawater tank (Jokura et al., Current Biology (2024))
Scientists have spotted for the first time two deep-sea “jelly” creatures readily turn into one individual following an injury.
The study, published in the journal Current Biology, may lead to breakthroughs in wound healing, researchers say.
Comb jellies are gelatinous animals related to jellyfish with translucent bodies living in the depths of the sea waters worldwide.
While regular jellyfish use the same opening to eat food and release waste, comb jellies have an anal pore to eject digested food.
They are among some of the earliest animal groups to emerge on Earth with unique nervous systems and strange features compared to other creatures.
In the new study, scientists observed a population of comb jellies kept in a seawater tank in the lab.
Researchers spotted an unusually large individual in the tank with atypical organs.
The comb jelly seemed to have two rare-end lobes and two of a sensory structure called an apical organ, instead of the usual one.
Scientists wondered if this unusual individual arose from the fusion of two injured jellies.
Further studies on the species revealed that over a single night, two individuals can seamlessly become one “with no apparent separation between them”, according to researchers.
When scientists poked at one of the lobes, the whole of the fused creature appeared to react with a startling response, suggesting there was no separation.
“We were astonished to observe that mechanical stimulation applied to one side of the fused ctenophore resulted in a synchronized muscle contraction on the other side,” study co-author Kei Jokura from the the University of Exeter said.
“The data imply that two separate individuals can rapidly merge their nervous systems and share action potentials,” Dr Jokura said.
In just about two hours, 95 per cent of the fused animal’s muscle contractions were found to be completely synchronous.
When the creature fed on fluorescently labelled brine shrimp, scientists found that the food particles went down the fused canal revealing that the animal’s digestive system was also fused.
The comb jelly expelled waste products from both its anuses, but not at the same time.
Researchers are perplexed how the fusion of two individuals into one helps the comb jellies as a survival strategy.
They hope future studies can unravel gaps in knowledge about the species.
Scientists say the latest discovery can also help better understand how the immune system recognises an entity as foreign.
“The capability of transplanted tissue to functionally integrate is unclear in many organisms,” researchers write.
“Our observations warrant further research into understanding the evolution of self–nonself recognition,” they say.
A better understanding of this process could lead to developments in research on regeneration and transplantation.
“Unraveling the molecular mechanisms underlying this fusion could advance these crucial research areas,” Dr Jokura says.
Watch: Jellyfish fuse together when they’re injured, scientists discover by accident
Joe Pinkstone
TELEGRAPH
Mon 7 October 2024
Two comb jelly fish quickly turned into one after suffering injuries
Some jellyfish can fuse together when injured to help their odds of survival, scientists have found.
Comb jellies have been caught on camera joining their movements into one, including a singular digestive tract to allow them to share food.
Scientists at Exeter University investigated this odd survival trait when they noticed one particularly large comb jelly in a seawater tank. The animal appeared to be one organism, but had two back ends and sensory structures.
Further experiments saw the team remove chunks of comb jellyfish bodies and put them in a tank and in nine out of 10 cases the two animals fused together.
When the animals were poked or prodded, the chimaera also responded as one entity, indicating a shared nervous system, the scientists say.
Mon 7 October 2024
Two comb jelly fish quickly turned into one after suffering injuries
Some jellyfish can fuse together when injured to help their odds of survival, scientists have found.
Comb jellies have been caught on camera joining their movements into one, including a singular digestive tract to allow them to share food.
Scientists at Exeter University investigated this odd survival trait when they noticed one particularly large comb jelly in a seawater tank. The animal appeared to be one organism, but had two back ends and sensory structures.
Further experiments saw the team remove chunks of comb jellyfish bodies and put them in a tank and in nine out of 10 cases the two animals fused together.
When the animals were poked or prodded, the chimaera also responded as one entity, indicating a shared nervous system, the scientists say.
‘Rapidly merge’
“Our findings suggest that ctenophores may lack a system for allorecognition, which is the ability to distinguish between self and others,” said Dr Kei Jokura, the study’s author.
“Additionally, the data imply that two separate individuals can rapidly merge their nervous systems and share action potentials.”
Further study showed that two individuals become one overnight with no apparent separation.
Dr Jokura said: “We were astonished to observe that mechanical stimulation applied to one side of the fused ctenophore resulted in a synchronised muscle contraction on the other side.”
The fused comb jellies had some individual movements for the first hour post-blending, but within two hours 95 per cent of the fused animal’s muscle contractions were completely synchronous.
The study, published in Current Biology, fed the fused jellyfish glowing shrimp and saw the food passed through one digestive system.
Research on regeneration
However, the comb jelly expelled waste products from both its anuses at different times.
The scientific team say it is unclear how the fusion of two individuals into one functions as a way of survival, and hope that more research investigates the phenomenon.
Dr Jokura said: “The allorecognition mechanisms are related to the immune system, and the fusion of nervous systems is closely linked to research on regeneration.
“Unravelling the molecular mechanisms underlying this fusion could advance these crucial research areas.”
Comb jellies fuse together when injured, study finds
Nicola Davis Science correspondent
THE GUARDIAN
Mon 7 October 2024
A comb jelly in the Bohol Sea, off the Philippines.Photograph: Alamy
It might not be what the Spice Girls envisaged when they sang 2 Become 1, but scientists have found comb jellies do actually fuse together if they are injured.
Researchers studying a species of the gelatinous marine invertebrates known as “sea walnuts” said they made the discovery after spotting an unusually shaped individual in the laboratory tank.
“I was very excited,” said Dr Oscar Arenas, co-author of the work, from the University of California, Berkeley.
Writing in the journal Current Biology, the team reports that, among other features, the creature appeared to have two “aboral ends”, or backsides.
In addition, Arenas said, the animal had two mouths – something the team had never seen before.
“This led us to wonder if it was the result of two independent animals fusing,” he said. “That same night, we began trying to replicate this observation.”
The team took pairs of sea walnuts – collected from different sites at different times – and, for each, removed part of the side of the body. Each pair was then pinned together overnight with their injuries touching.
The results revealed that, in nine out of 10 cases, the individuals had fused.
“Once we realised we could consistently reproduce the fusion, we shortened the time, and eventually we found the fusion occurred within a few hours in a petri dish,” Arenas said.
The team notes it is not the first time the grafting of comb jellies – or ctenophores – has been reported, but they say their experiments expand upon such observations.
Among other findings, the team found when they prodded one side of the fused creature both individuals jerked and contracted, a result that suggests the nervous systems of the pair might have merged, they say.
Arenas said the finding was exciting because very little is known about the ctenophore nervous system.
“Moreover, given that ctenophores are now considered descendants of the ancestors of all other animals, studying how their nervous system works is crucial for understanding the basic principles of neuronal function,” he said.
“Beyond that, our observations suggest that ctenophores might serve as an excellent model for investigating evolutionary processes of self-recognition systems and advancing our understanding of tissue grafting and regeneration in many tissues, including the nervous system.”
The idea that the nervous systems had merged was supported by the discovery that, one hour after the comb jellies were paired, their muscle contractions started to synchronise. An experiment involving six fused pairs suggested 95% of contractions within each pair were completely synchronous after two hours.
The researchers found that when they fed fluorescently labelled food to one of the comb jellies, particles passed into the digestive system of the other. The digested waste products, however, were expelled from both anuses in an unsynchronised manner.
Arenas said the study suggested comb jellies had few mechanisms for distinguishing their own tissues from those of others of the same species.
“I am convinced that it provides insight into the molecular mechanism of how single cells recognise themselves when they coalesce to become multicellular animals.”
Mon 7 October 2024
A comb jelly in the Bohol Sea, off the Philippines.Photograph: Alamy
It might not be what the Spice Girls envisaged when they sang 2 Become 1, but scientists have found comb jellies do actually fuse together if they are injured.
Researchers studying a species of the gelatinous marine invertebrates known as “sea walnuts” said they made the discovery after spotting an unusually shaped individual in the laboratory tank.
“I was very excited,” said Dr Oscar Arenas, co-author of the work, from the University of California, Berkeley.
Writing in the journal Current Biology, the team reports that, among other features, the creature appeared to have two “aboral ends”, or backsides.
In addition, Arenas said, the animal had two mouths – something the team had never seen before.
“This led us to wonder if it was the result of two independent animals fusing,” he said. “That same night, we began trying to replicate this observation.”
The team took pairs of sea walnuts – collected from different sites at different times – and, for each, removed part of the side of the body. Each pair was then pinned together overnight with their injuries touching.
The results revealed that, in nine out of 10 cases, the individuals had fused.
“Once we realised we could consistently reproduce the fusion, we shortened the time, and eventually we found the fusion occurred within a few hours in a petri dish,” Arenas said.
The team notes it is not the first time the grafting of comb jellies – or ctenophores – has been reported, but they say their experiments expand upon such observations.
Among other findings, the team found when they prodded one side of the fused creature both individuals jerked and contracted, a result that suggests the nervous systems of the pair might have merged, they say.
Arenas said the finding was exciting because very little is known about the ctenophore nervous system.
“Moreover, given that ctenophores are now considered descendants of the ancestors of all other animals, studying how their nervous system works is crucial for understanding the basic principles of neuronal function,” he said.
“Beyond that, our observations suggest that ctenophores might serve as an excellent model for investigating evolutionary processes of self-recognition systems and advancing our understanding of tissue grafting and regeneration in many tissues, including the nervous system.”
The idea that the nervous systems had merged was supported by the discovery that, one hour after the comb jellies were paired, their muscle contractions started to synchronise. An experiment involving six fused pairs suggested 95% of contractions within each pair were completely synchronous after two hours.
The researchers found that when they fed fluorescently labelled food to one of the comb jellies, particles passed into the digestive system of the other. The digested waste products, however, were expelled from both anuses in an unsynchronised manner.
Arenas said the study suggested comb jellies had few mechanisms for distinguishing their own tissues from those of others of the same species.
“I am convinced that it provides insight into the molecular mechanism of how single cells recognise themselves when they coalesce to become multicellular animals.”
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