Jin Yong's novel "Tianlong Babu" has a Tianshan tongyao, who returns to her old age and returns to her childhood every 30 years.
There is a jellyfish in the ocean that can repeatedly change back to "childhood". It is the only known species in the world that can do this, and is called the "immortal jellyfish". Scientists have studied it for decades.
Reuters reported on August 31 that the study recently published by Spanish scientists in the Proceedings of the National Academy of Sciences in the United States unveiled the genetic code of "immortal jellyfish".
Will this small jellyfish with a diameter of four or five millimeters make human beings' dream of "immortality" come true?
There is a mutation in the gene of this jellyfish
The scientific name of the "immortal jellyfish" is Turritopsis dohrnii, Chinese called the lighthouse jellyfish. Its ability to rejuvenate has been a mystery in the biology community for decades.
Maria Turner, Victor Quesada and colleagues at the University of Oviedo in Spain plotted the genetic sequence of an immortal jellyfish.
Different life stages of immortal jellyfish
Like other jellyfish, the life cycle of the lighthouse jellyfish consists of two parts: the hydra body in the asexual stage, which lives on the seabed and sustains life during periods of food shortage. When the conditions are ripe, they become common jellyfish-like and have sexual reproduction.
The authors write that while many types of jellyfish have some ability to reverse aging and restore youthfulness, most lose this ability once they reach sexual maturity. This is not the case with lighthouse jellyfish.
They compared the genetic sequence of the lighthouse jellyfish with that of its close cousin, the crimson jellyfish, which does not rejuvenate, to see what was the difference.
It has been demonstrated in humans and other species that the ends of chromosomes, called cellular telomeres, shorten in length with age. This is an irreversible sign of getting older.
The comparison revealed that there were mutations in the genomes of lighthouse jellyfish that may have made them better at replicating and repairing DNA. They also seem to be better at maintaining telomeres.
This is the latest result of lighthouse jellyfish research and may give humans a new direction in the fight against aging.
Two students found it rejuvenating
This species was first discovered in the Mediterranean in 1883. 100 years later, two students accidentally discovered its eccentric "immortality."
In the summer of 1988, Christian Sommer, a German student in his 20s, and classmate Georges Bavelerello vacationed in the small town of Rapallo on the Italian Riviera. Sommer is a student of marine biology at the University of Salento in Italy.
While on vacation, do some research on small jellyfish. Between the cliffs of Portofino, they dive into the sea to find the jellyfish, collecting them with very fine nets, because the jellyfish are difficult to detect in the seawater.
They collected a small purple jellyfish and raised it in the lab of their teacher, Professor Ferdinando Boro.
Sommer forgot about them.
A few days later, remembering to check again, Sommer found that the jellyfish was missing and that there were dry hydras deposited under the tank.
The two students were confused. They also collected some hydra body jellyfish to monitor until they grew into jellyfish.
In general, these jellyfish mature before laying eggs and producing larvae.
But when they examined it again, they were surprised to find many new hydra bodies. After these hydra grow into swimming jellyfish, they are stimulated or stressed, and then directly change back into the hydra body, skipping the fertilization and larval stages.
Professor Boro said: "This observation is revolutionary. ”
Biologists say: This is impossible
Sommer and Bavelero's observations, reported at a symposium, gave the jellyfish the nicknames "immortal jellyfish" and "immortal jellyfish."
Jellyfish research expert Volcker Schmid said: "It's impossible. ”
The research institute will be in a marine laboratory. Boro said they did it on the spot for Schmid to see.
Diving brings back jellyfish, under Schmid's eyes, with a light forceps of forceps, the jellyfish becomes a ball of paper like a "sac", falling to the bottom of the tank, and then into a hydra body.
Schmid was surprised.
This discovery has attracted worldwide attention. Boro said another of his students, Stefano Pirano, attended the workshop together, joined the research, and began working with Schmid.
Butterflies turn back into caterpillars
When they were collecting this jellyfish in Rapallo, where Friedrich Nietzsche was a century ago, he said: "Everything is going on, everything is back; Eternally turning the wheel of existence. Everything is dead, everything is blossoming again..."
The rejuvenation of the lighthouse jellyfish has become a meme in biology and has crossed over to the field of literature and art.
In 1996, Boro and his colleagues published a paper entitled "Reversing life cycles." He made an analogy: a butterfly turned back into a caterpillar.
There are other metaphors: the chicken turns back into an egg and then gives birth to another chicken; Frogs turn back to tadpoles; The old man became younger and younger and changed back into a fetus.
Later, it was also known as "Benjamin Button Jellyfish", nicknamed after the protagonist of the movie "Rejuvenation". This characteristic also appears in the Japanese TV series "14 Months".
Perhaps the most avid scientist who studies lighthouse jellyfish is Japan's Shinkubota.
For more than a decade, he spent at least 3 hours a day caring for lighthouse jellyfish, and went abroad to attend academic conferences to keep jellyfish in portable refrigerators. He's also a singer, releasing 6 albums in five years, and many of the dozens of songs are "Lighthouse Jellyfish Songs", such as: "I have a special secret that no one else can have: I can – yes, I can!" - Rejuvenation. ”
"Reborn" 10 times in two years
How long can lighthouse jellyfish live? This is a tricky question.
"A lot of deep-sea scientific research takes a long time." Miranda, director of the Natural History Museum in London, said: "The survival study of jellyfish must also have perfect conditions, and they will not be harmed by anything external, such as humans or other predators." ”
Since 1990, Shinkubota has maintained a life cycle of immortal jellyfish populations. He cut the tiny brine shrimp eggs into thin slices under the microscope, so that the baby jellyfish could easily eat them. He reported that in two years, his jellyfish colonies returned to their natural state of youth as many as 10 times, sometimes at intervals of only one month.
The lighthouse jellyfish may change the rules, at any stage of its life, to revert to the hydra body, restarting its life cycle again and again. Simply put, it doesn't die.
But that's just not dead in biology. It will die, possibly killed by predators such as fish, turtles, and sea slugs, which can be eaten.
Immortal jellyfish were first discovered in the Mediterranean, but they are found in oceans around the world, and the genes of immortal jellyfish are the same everywhere, so it is impossible for it to travel only through ocean currents. A popular theory is that ships spread them widely, and its "immortality" makes it an excellent hitchhiker.
But immortal jellyfish look different everywhere. The researchers found that immortal jellyfish in tropical regions such as Panama have only 8 tentacles, while in the temperate waters of the Mediterranean And Japan, there are 24 or more. It's unclear why it's different.
One reason immortal jellyfish travels around the globe without attracting attention may be that it has no noticeable negative effects and is not as wild as other invasive species.
You can't catch jellyfish to make a skin cream
Regarding the latest research by Spanish scientists, Monty Graham, director of the Florida Institute of Oceanography and a jellyfish expert, said it has no direct commercial value.
"We can't think of it as: Hey, we're going to capture these jellyfish and turn it into a skin cream," he said, "and I think it's one of those papers that's going to open the door to a new research direction worth pursuing." ”
The Aquarium of Paris displays 45 different species of jellyfish
Boro's student Stefano Pirano believes that immortal jellyfish may help fight cancer. Like cancer cells, "some cells of this jellyfish should be able to turn off some genes and turn on some others, reactivating the genetic programs used in the early stages of the life cycle." ”
By studying how immortal jellyfish cells do it, he said, scientists may find clues to treat cancer.
Maria Turner, author of the latest study, says the genes they found may be linked to human aging. They can inspire regenerative medicine or provide insights into age-related diseases such as cancer and neurodegenerative diseases.
"The next step is to explore these genetic variants in mice or humans." She said.
Orange Persimmon Interactive City Express reporter Jin Yingying comprehensive report