Frankenstein is not fiction? There are also "stitched monsters" in the ocean~

Tuchong Creative

Frankenstein, I believe everyone in front of the screen knows that he is a man-made man made of different human bodies created by the British female writer Mary Shelley. He is the most famous "stitched monster" in the world. Frankenstein is fictional, but in reality there are indeed creatures that can be stitched together to form a new living individual.

Comb jellyfish, commonly known as sea walnuts. Although the word "jellyfish" is in its name, it is not actually a Cnidaria animal, but a Ctenophore. The jellyfish and red coral we commonly see belong to the Cnidaria. The Ctenophore consists of almost only various types of comb jellies.

You may be curious, this comb jellyfish has the word "jellyfish" in its name and looks like a jellyfish, so why does it belong to two different categories?

In fact, although comb jellies and jellyfish look similar, there are actually many fundamental differences. For example, the way they hunt. Jellyfish rely on cnidocytes (specialized cells) to hunt and defend; comb jellies do not have cnidocytes, but instead use special glial cells (colloblasts) to stick to their prey. Another example is the nervous system. Jellyfish only have simple nerve nets, while comb jellies have discrete neurons and sensory organs, and their nervous systems are more complex.

The reason why comb jellies and jellyfish look alike is that they live in similar environments, and in the process of adapting to the environment, they have evolved morphological or functional characteristics. This phenomenon is called "convergent evolution." Just like fish and dolphins, the former is fish and the latter is mammal. This phenomenon is very common in nature. Similar examples include bats and birds, the former is mammal and the latter is aves. Cacti and succulents. The former belongs to the Cactaceae family, while the latter does not belong to the same taxonomic family or genus.

There are many interesting things about comb jellies. The surface of the comb jellyfish is lined with eight comb plates, which are covered with cilia. The rhythmic movement of these cilia makes the comb jellies swim in the water very gracefully. This unique movement method, coupled with the comb jellies' ability to bioluminesce, makes them look like walking neon lights in the water.

However, the most unique thing about comb jellies is that two injured comb jellies can be "stitched" together to form a new individual and achieve the purpose of healing.

On October 7, "Contemporary Biology" published an article titled "Rapid physiological integration of fused ctenophores" that revealed the discovery process of the "suturing ability" of comb jellies. One day, researchers noticed an abnormal comb jelly in a laboratory seawater tank. This individual was abnormally large, and had two aboral ends and two apical organs. From the appearance, it looked like two individuals fused together. Therefore, the researchers boldly speculated that comb jellies have the ability to fuse, and conducted experiments based on the speculation.

The researchers selected comb jellies collected from different locations and on different dates, cut off part of the lobe of each individual, aligned the incisions and fixed them in a dissecting dish overnight, and conducted 10 independent transplantation experiments.

By observing fluorescently labeled food particles, the researchers found that the digestive systems of the fused comb jellies achieved functional coupling of material transfer, that is, digestion products could flow between the two originally independent digestive systems. This shows that the digestive systems of the two individuals are not only physically connected, but also functionally coupled.

Although the food transport and digestive systems are shared, the excretion functions of the comb jellies are not synchronized after the fusion, and the two anuses excrete independently. In short, although the two comb jellies are fused together, they still retain a certain degree of independence.

In other words, unlike Frankenstein, the comb jellyfish after fusion is not a "new individual" but "two individuals sharing a fused body."

Seeing this, some friends may have questions. Biological xenotransplantation is not only difficult, but also easy to cause rejection reactions. Why can comb jellies fuse together so easily?

Researchers speculate that comb jellies may lack an allorecognition system, which is an immune mechanism used by organisms to distinguish between "self" and "non-self". It helps organisms identify and exclude foreign invaders (such as bacteria, viruses, parasites, etc.), as well as identify and tolerate their own tissues and cells. Different blood types cannot be transfused, and rejection reactions during organ transplantation are closely related to the allorecognition system.

The lack of a homologous recognition system in comb jellies may have been a result of their free-floating lifestyle during evolution.

The fusion of comb jellies may also be related to their unique nervous system. Comb jellies do not have a central control organ like the brain, which makes their nervous system more plastic and easier to adapt to the new state after fusion.

In addition, in the experiment, the two damaged comb jellies were able to heal quickly and form a continuous epidermis and glial layer after the tissue was cut, indicating that they have strong regeneration and wound healing capabilities. This ability may also be the reason that helps them achieve physiological integration during the fusion process.

There are still many mysteries about comb jellies that have not been solved. For example, what advantages does this ability have for the survival and reproduction of comb jellies? How is the energy metabolism of fused individuals regulated? What impact does fusion have on the population dynamics of comb jellies and the function of the ecosystem?

In addition to comb jellies, some other organisms have similar fusion abilities. For example, hydras and some cnidarians (such as fire corals) can regenerate tissues after trauma and even fuse with other individuals in some cases. These organisms have simple tissue structures that can form continuous cell layers when they come into contact with each other.

Sea squirts can form groups through "symbiotic fusion", in which they share blood circulation and nervous systems. In addition, sea squirts can identify and integrate individuals with similar genetics to themselves, while rejecting incompatible individuals.

Some bryophytes, such as some species of the genus Lithops, can fuse with other bryophyte individuals as they grow, forming a continuous plant structure. This phenomenon usually occurs in humid environments, where they increase their chances of survival by sharing water and nutrient resources.

Research on comb jellies and organisms with similar abilities can not only help us understand where humans came from, but also has important implications for improving our medical technology.

Comb jellies may be one of the earliest groups to differentiate from the common ancestor of animals. The fact that comb jellies have the ability to fuse suggests that early differentiated animals may not have a complex immune rejection system. This discovery provides new ideas for studying the origin of the self-recognition mechanism in animal evolution and helps scientists understand the evolution of this mechanism in multicellular organisms.

The fusion ability of organisms such as comb jellies provides us with new ideas for studying tissue repair and regeneration. By deeply studying their molecular mechanisms, we can develop new treatments for diseases such as trauma and organ failure. Understanding the fusion mechanisms of these organisms can help solve the problem of immune rejection in organ transplantation and improve the survival rate of transplanted organs. The growth and spread of tumors also involve cell fusion and migration. Studying the fusion mechanisms of organisms such as comb jellies can help us gain a deeper understanding of the occurrence and development of tumors and provide new targets for cancer treatment.

The fusion ability of comb jellies reveals a corner of life evolution for us, and also provides new inspiration for regenerative medicine, cancer research and other fields. With the deepening of research, I believe we can find more answers to the mysteries of life from these seemingly simple marine organisms.

This article is a work supported by the Science Popularization China Creation Cultivation Program

Author: Bigan Yao (popular science author)

Reviewer: Zhao Xumao, Young Researcher, Lanzhou University

Produced by: China Association for Science and Technology Department of Science Popularization

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.