astralavista

French biologists say thay have proof that immortality is impossible. Single-celled bacteria like E. coli, and even some humans, have long nutrured hope that they may eascape aging and death. No so, says Eric J. Stewart of the Institut des Hautes Etudes Scientifique in France. "No life strategy is immune to the effects of aging and suggest that this may be because immortality is too costly or is mechanistically impossible," he writes. "This may be bad news for people who had hoped that advances in science might eventually lead to human immortality."
Scientists have assumed that cells that divide symmetrically do not age and are functionally immortal. Stewart and his colleagues tested this idea by analyzing repeated cycles of reproduction in Escherichia coli, a bacteria that reproduces without a juvenile phase and with an apparently symmetric division.
E. coli is a rod-shaped organism that reproduces by dividing in the middle. Each resultant cell, Stewart writes, inherits an old end or pole and a new pole, which is made during the division. The new and the old pole contain slightly different components, so although they look the same, they are physiologically asymmetrical.
Stewart found that the cells "inheriting old poles had a reduced growth rate, decreased rate of offspring formation, and increased risk of dying compared with the cells inheriting new poles. Thus, although the cells produced when E. coli divide look identical, they are functionally asymmetric, and the old pole cell is effectively an aging parent repeatedly producing rejuvenated offspring."
That may take some wind from the sails of transhumanists and others who believe in the possibility of immortality in some shape.
At least Stewart did try to offer some solace. He said his research provides "an excellent genetic platform for the study of the fundamental mechanisms of cellular aging and so could provide information that might ameliorate some of the unpleasantness of the human aging process."