transdifferentiation

IMMORTAL JELLYFISH — request from elocinbored
Turritopsis nutricula
©Cibermitanios.com.ar

Turritopsis nutricula, the potentially immortal jellyfish, is a hydrozoan whose  jellyfish form can revert back to the polyp stage after becoming sexually mature. It is the only known case of a metazoan capable of reverting completely to a sexually immature, colonial stage after having reached sexual maturity.

It does this through the cell development process of transdifferentiation.

Cell transdifferentiation is when the jellyfish “alters the differentiated state of the cell and transforms it into a new cell”. In this process the mature jellyfish transforms back into the polyps stage creating a new polyp colony. Theoretically, this process can go on indefinitely, effectively rendering the jellyfish biologically immortal, although in nature, most Turritopsis, like other medusae, are likely to succumb to predation or disease in the plankton stage, without reverting to the polyp form.

No single specimen has been observed for any extended period, so it is not currently possible to estimate the age of an individual, and so even if this species has the potential for immortality, there is no laboratory evidence of many generations surviving from any individual.

Source: http://en.wikipedia.org/wiki/Turritopsis_nutricula

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22 June 2013

Brain Marrow

Converting one cell type into another – a process called transdifferentiation – doesn’t occur naturally in humans, or in most other creatures for that matter, though it can be induced artificially. But why would researchers want to make a cell switch identities? Well, just imagine if a patient had a disease where certain cells were damaged or dying. Making some of the patient’s other cells adopt the identity of the diseased cells could help to repair or replace the damaged tissue without the need for donor cells or organs. Researchers have now identified an antibody that binds to bone marrow cells and induces them to become nerve cells – their characteristic long skinny projections seen here (stained green) tipped with growth-directing regions called growth cones (stained red). Extracting a person’s bone marrow and converting it into nerve cells could potentially provide a convenient source of cells for repairing brain or spinal cord injury.

Written by Ruth Williams

What can we learn from the “immortal” jellyfish? - by Dr Laura Sidney

There is a species of jellyfish, discovered in 1992, which can effectively live forever. Turritopsis dohrnii (previously classified as Turritopsis nutricula) is a small jellyfish that can revert to an immature larval stage after reaching adulthood. To do this, its cells go through transdifferentiation, a process in which a non-stem cell can become any other cell.

So what can we learn from this exceptional species? In stem cell biology, we already have some understanding of how stem cells can naturally turn into different cell types of the body. However, if we better understood the transdifferentiation process, we could learn how to turn any type of cell into a different type of cell. With this knowledge, we may be able to create therapies to reverse some of the more debilitating effects of ageing such as cancer, arthritis and Alzheimer’s disease.

However, this may be a long way off. Keeping T. dohrnii in captivity is challenging, and requires close attention to the jellyfish’s environment, making them difficult to study. In fact, there is only one scientist culturing them consistently, Shin Kubota. An interesting article from the New York Times, detailing his work and views on ageing can be found here.

YouTube Video Link: SciShow How to Live Forever? Be a Jellyfish - https://www.youtube.com/watch?v=2kLSiE-eNjw