Scientists have uncovered something pretty astounding which might carry big implications in regenerative medicine: the sea walnut, Mnemiopsis leidyi, can survive injury by fusing with another organism of its kind to form a single working organism, essentially merging their physical bodies along with their nervous and digestive systems. Such a wonderful discovery was first marked by a groundbreaking study published in Current Biology, led by Dr. Kei Jokura of the University of Exeter and Japan’s National Institutes of Natural Sciences.
The Discovery of Fusion Capability
The scientists first observed a big comb jelly during an experiment conducted at a laboratory with two rear ends and two apical organs-the sensory structures responsible for helping it orient its body to thus establish its balance. In the normal state of things, comb jellies have only one apical organ. Thus what the scientists saw prompted quite an interest in the matter. It was realized that what they had seen was not a single jelly but two which had managed to merge into one having met injuries. The accidental discovery called for a more comprehensive exploration into how and why such a merging process took place.
In subsequent experiments, the researchers harvested lobes from single comb jellies and set them alongside other injured jellies in tanks of seawater. In 90% of attempts, the jellies fused together overnight to form a single organism that survived at least three weeks. They fused tissues, but it was as though they also integrated their systems of physiology.
Coordination of Nervous and Muscular Systems
Another surprising aspect of the fusion process was how fast two nervous systems of the comb jellies became synchronized. When the other part of the body was touched or stimulated, it reacted all over the organism, when originally two different organisms. Dr. Jokura and his team ran experiments to prove the fact that it was fully merged where this fused jelly responded to external stimuli with perfection to external stimuli.
Even muscle contractions were coordinated rapidly with the two fusing together. It was observed within two hours of fusion that 95% of the muscle contractions of the fused animal occurred. This means that not only were their nervous systems fused but also so was their control over the merged body almost in the blink of an eye.
We were surprised to see that mechanical stimulation applied on one side of the fused ctenophore caused synchronized contractions of muscles on the other side,” Dr. Jokura said. The researchers captured high-resolution images of the process, detailing how quickly the jellies became one functioning unit.
Digestive Systems Integration
Their digestive systems have merged, just like their nervous and muscular systems. The researchers fed the fused animals fluorescently tagged brine shrimp to track the digestion process. They watched in awe as, when food entered one mouth, it exited both anuses. Unfortunately, not at the same time – through a single digestive tract. It is simply incredible integration of those comb jellies after they were joined.
This linking of digestive systems allows the two organisms to pool their resources, thus any part of the organism that cannot feed itself again can survive; such integration is barely observed in other species, and it would seem that comb jellies are bestowed with a special biological machinery that supports this extraordinary metamorphosis.
Implications of Allorecognition and Immune Response:
Perhaps the most interesting feature of this finding is that it might shed new light upon the field of allorecognition – the biological mechanism whereby organisms distinguish their own cells from those of another. The relationship between most animals and their immune systems, which reject tissues foreign to them through a mechanism called graft rejection, is co-extensive with this ability. However, the comb jellies apparently have a defect in allorecognition altogether which allows them to integrate another individual’s tissues without alerting the immune system.
Our results show that ctenophores maybe not having any system for allorecognition or the ability to recognize self from others. Which means they can literally fuse into one organism with another and become completely functional as a single organism, said Dr. Jokura.
This inability of the two embryos to recognize each other’s genetic makeup may have tremendous implications for medical science, particularly in organ transplantation. Normally, organs transplanted into humans and other animals are usually rejected by the immune system following complications that have to be kept at bay with immunosuppressive drugs all through a lifetime. If mechanisms responsible for the ability of comb jellies to fuse without complications can be more lucidly understood by scientists, such information may sooner or later help break through potential limitations to reducing rejection in human transplantations.
Possible Course of Future Research
Though this fusion ability is unlikely to be a frequent encounter in the wild, since the adult comb jelly presumably leads an independent life, gigantic implications were drawn from this discovery. Dr. Jokura and his team are now focusing on unraveling the molecular and genetic processes which seem to underlie this sort of fusion. Knowing the way that comb jellies can fuse their nervous, muscular, and digestive systems without any kind of immune rejection might open new avenues to regenerative medicine.
The mechanisms of allorecognition are immune-system-related, while the nervous system fusion has much to do with the regeneration research, said Dr. Jokura. “Discovering the molecular basis for this fusion process might hold the secret in making progress in such vital areas of study.”
The relatively simple biological systems of comb jellies are hoped to gain enough insights on the applicability to human biology through the study by scientists. According to scientists in this discovery, insights gained will relate organisms from very distant evolutionary branches to contain clues that might revolutionize modern medicine. Through the comb jelly’s capacity to fuse and its ability to work like one body, avenues for new techniques in tissue regeneration, nerve repair, and even transplant surgery are open.
Historical Background and Wider Connotations
Interestingly, hybrid comb jelly is not a first-time documented case. During the 1930s, marine biologist B. R. Coonfield performed experiments that gave rise to a solitary comb jelly, composed of the bodies of four individuals. However, modern scientific tools, such as high-resolution imaging, allow researchers to observe this fusing process at much finer scales than was previously possible and provide new insights into how such creatures merge their systems in so resourceful and all-encompassing a manner.
While their translucent body and bioluminescence may make it resemble an extraterrestrial creature, comb jellies might be just the ticket to solving some of modern medicine’s thorniest problems. They fuse without rejection, share resources, and work as one organism, making them the perfect subject for further study into tissue regeneration and immune system modulation
