Students Christian Sommer and Giorgio Bavestrello collected Turritopsis polyps, which they kept and monitored until medusae were released. It was 100 years later, in the 1980s, that their immortality was accidentally discovered. dohrnii was first described by scientists in 1883. 'We might be distracted watching much larger jellyfish, but the tiny things such as this can inform so much of our science about these animals,' says Miranda. This life cycle reversal can be repeated, and in perfect conditions, it may be that these jellyfish would never die of old age. They can then mature again from there as normal, producing new, genetically identical medusae.
Transdifferentiation reprogrammes the medusa's specialised cells to become specialised polyp cells, allowing the jellyfish to regrow themselves in an entirely different body plan to the free-swimming jellyfish they had recently been. Medusa cells and polyp cells are different - some cells and organs only occur in the polyp, others only in the adult jellyfish. The process behind the jellyfish's remarkable transformation is called transdifferentiation and is extremely rare. This phenomenon has been likened to that of a butterfly which, instead of dying, would be able to transform back into a caterpillar and then metamorphose into an adult butterfly once again.
Over the next 24-36 hours, this blob develops into a new polyp - the jellyfish's previous life stage - and after maturing, medusae bud off.
It then settles on the seafloor as a blob-like cyst. When the medusa of this species is physically damaged or experiences stresses such as starvation, instead of dying it shrinks in on itself, reabsorbing its tentacles and losing the ability to swim. It has been dubbed the immortal jellyfish. The hydrozoan Turritopsis dohrnii, an animal about 4.5 millimetres wide and tall (likely making it smaller than the nail on your little finger), can actually reverse its life cycle.
0 kommentar(er)
