To the vast question, “What is death?”, most scientists have a fairly simple answer: it is the irreversible cessation of the functioning of an organism as a whole. However, some cells can continue to function even after death, and this is proven by the practice of organ donation. Based on this observation, a team of researchers led by Peter A. Noblefrom the University of Washington, was interested in his latest study to what happens inside organisms after they die.
In a summary published in The Conversationthese researchers show that certain cells, when fed with nutrients, oxygen, bioelectricity or even biochemical signals, can transform after their death into multicellular organisms with completely new functions. They would then be the incarnation of a form of “third state”, located beyond the traditional boundaries between life and death.
The team of scientists discovered, for example, that skin cells extracted from deceased frog embryos were able to adapt to the new conditions of a Petri dish by laboratory. The latter managed to reorganize themselves spontaneously into multicellular organisms, called xenobots.
These new organisms then adopted behaviors that went well beyond their original biological roles. For example, they used their cilia, small hair-like structures, to navigate and move through their environment. Yet in a living frog embryo, these same cilia are typically used to move mucus.
The conditions of the “third state”
Several factors influence the survival and functioning of certain cells after the death of an organism, including environmental conditions, metabolic activity, and preservation techniques.
So active cellswhich require a continuous energy supply to maintain their function, are more difficult to culture than cells with lower energy requirements. Also, preservation techniques like cryopreservation may allow samples such as bone marrow to function similarly to those from living donor sources.
Inherent survival mechanisms also play a key role in cell survival. For example, researchers observed a significant increase in the activity of genes related to stress and those related to the immune system after the organism dies. Finally, factors such as age, health, sex and species type influence the “third state”. It is important to note that these multicellular organisms have a limited lifespan and naturally degrade after four to six weeks.
Researchers don’t yet know how the interaction of these variables allows these cells to continue functioning after an organism dies, but the “third state” nonetheless opens up promising prospects for new medical treatments.
Source: www.slate.fr
