SAN FRANCISCO – Scientists at the University of California, San Francisco, studied a hydra, a tiny strange sea creature similar to jellyfish that tears apart its own body before it can eat its prey. This small freshwater animal uses an incredibly complicated process to open and close its mouth, leaving biologists and physicists stunned.
In the paper published in Biophysical Journal, the hydra tears a hole through its epithelial tissue and its mouth literally disappears when it closes. The tiny creature uses a set of tentacles to catch its prey and take it towards the mouth.
The team of biologists and physicists observed the morphological changes that occurred at the cellular levels and found that the hydra has the ability to rearrange the cells of its tentacles in order to make a wider opening. By rearranging the positions of its skin cells, the animal opens and closes (or disappears) its mouth in less than a minute.
UC Irvine professor Robert Steele injected hydra with red and green fluorescent proteins, which were tagged to cytoplasmic proteins in the endodermal and ectodermal epithelial cells of the animal. This process allowed scientists to see what happened inside and out of the creature as it fed.
Lead author Eva-Maria Collins studied the genetically engineered hydra. The animal’s hypostome has contractile filaments named myonemes, which the hydra arranges in rings and spokes, similarly to a spider web. Collins found that the creature’s mouth opens when the spokes contract and closes when the rings do. This process is similar to that of the pupils in human eyes when they are dilated and constricted.
Collin alongside her team also proved that the cells around the opening mouth do not rearrange themselves, but they change shape and turn much narrower and longer to accommodate the hydra’s widening gap.
When talking about hydras, Greek mythology doesn’t seem that far from reality
In Greek mythology, Hydra was venomous snake monster with multiple heads and incredible regeneration powers. Real hydras do regenerate with amazing skill and some biologists have even said that they are immortal. Real hydras also recall the beast of mythology because they have stinging cells capable of firing venomous harpoons.
Source: National Geographic