The feeling of hunger seems pretty simple on the surface, but behind the scenes, it involves a complex network of transmissions and signals by multiple hormones that influence whether or not to eat another serving. The ability to know when to stop eating seems to be widespread among animals, suggesting that it may have deep evolutionary roots.
New research suggests that at least part of the system can be traced back to animal origins. Researchers have identified a hormone that jellyfish use to determine when they are full and stop eating. And they found that it could elicit the same response in fruit flies, suggesting that this system may have operated in the ancestors of these two very distant animals. increase. Its ancestors would have lived before the Cambrian.
feed the fish (or jellyfish)
Given that there is no mouth equivalent, it may seem difficult to tell if a jellyfish is eating, let alone hungry.However, a team of Japanese researchers found that jellyfish seeds Cladonema pacificum There are many typical behaviors during feeding, such as tentacles hooking on prey and retracting the tentacles into the bell so that it can digest the prey. And continuing to feed the jellyfish’s brine shrimp eventually slows down this process, indicating that the animal senses that it’s getting enough food. )
To find out how this is regulated, researchers dissected the jellyfish’s core, which contains the digestive tract, and the bell, which contains much of the animal’s neural network. We next examined which genes were activated in these tissues when animals were either hungry or satiated. And, to avoid confusion, we also created a complete list of genes that are active in brine shrimp fed to jellyfish. We have created a list of potential hormones that have not.
Overall, we came up with 43 genes that code for small molecules that may act as hormones. These are typically normal-sized proteins with repeating sequences so that they can be chopped up to form collections of short amino acid chains called peptides. may be further qualified by
The researchers chemically synthesized all 43 genes and tested whether they could alter feeding behavior. They found five that do. Her four of them were activated after the animals were fed to the point where they stopped feeding.
In this study, researchers chose to focus on one of these. The unfortunate name is (N)GPPGLWamide (they called it GLWa, I do the same). Treatment of jellyfish with GLWa suppressed tentacle contraction during feeding to approximately the same extent as when animals were fed multiple brine shrimps. It is also interesting that the gene encoding it is found in a wide range of cnidarians, a group of radially symmetrical organisms that includes jellyfish, corals and sea anemones. This suggests that there may be
