A photo from open sources
Important breaking news: biologists from Tufts University (USA) managed to restore the ability to regenerate tail tissue in tadpoles. Such work could be considered ordinary, if not one circumstance: the result was achieved in a non-trivial way, with the use of optogenetics, which is based on management cell activity with the help of light. The ultimate goal of all such research – discover the natural mechanisms that control restoration of body parts, and learn to incorporate them in humans. Tadpoles are the best suited for this task, since at the early stage of development retain the ability to replace lost limbs, but then sharply lose it. If you cut off the tail of individuals, entered the so-called refractory period, they will not be able to grow it again. Internal systems controlling regeneration, still present in their bodies, but for some reason stopped. Michael Levin and colleagues forced them to earn again, actually turning physiological time back. Great how they did it. One group of tadpoles, devoid of tail, was grown in a container illuminated by short flashes of light for two days; the other lived in full in the dark. As a result, the tadpoles of the first group recovered full tail tissue, including structures of the spine, muscles, nerve endings and skin. Tadpoles second overcome the consequences amputations could not, as expected at their age. If it looks like focus, it’s only partly. To figure out why it happened The principle underlying the experiment needs to be clarified. Indeed, all animals in one stage life cycle, subjected to identical manipulations. The only thing, what distinguished the two groups was the presence or absence of lighting. However the light was not the true cause of the change. He served a remote switch that actuated the factor, which (in a not entirely clear way) started the regeneration process. Hyperpolarization acted as such a factor. transmembrane cell potentials; or simpler – bioelectricity. Optogenetics allows you to build an experiment is relatively simple. Archerhodopsin Photosensitive Protein mRNA Molecule Injection were introduced into tadpoles. This led to the fact that after some time on the surface of ordinary cells located in the thickness of the tissue, “squirrel pumps” appeared. Under the condition of stimulation with light (and only in in this case) they induced an ion flow through the membrane, thereby changing its very electrical potential. Essentially besides membrane light-activated pumps, scientists to help tadpoles nothing not offered. However, only the impact on electrical cell properties turned out to be enough to run in the body complex cascade of regeneration processes. In turn, thanks optogenetics to cause these changes from the outside is simple, you just need shine on the tadpole. Regeneration remains one of the main mysteries of biology. In 2005, Science magazine ranked among 25 The most important problems facing science, the next question: What Controls Organ Regeneration? Unfortunately, scientists have so far failed to end to understand why some animals at any stage of their lives freely restore lost parts of the body, while others lose this ability forever. Once your body knew how grow an eye or arm. It was a long time ago, at the very beginning of life in as an embryo. Specialists are interested in where this disappears. knowledge and whether it is possible to revive it again in an adult. IN the present moment, the search for most biologists is concentrated in mainly around gene expression or chemical signals. IN Michael Levine’s labs answer the riddle of regeneration hope discover in another phenomenon, bioelectricity, and these hopes, by apparently, not without reason. That in a living organism there are electric currents, known from the time of the experiments Galvani. However, few have studied their impact on development so intently, as Levin does. Bioelectricity has long had a chance become a worthy subject of experiments, but the molecular revolution in biology of the second half of the twentieth century supplanted research interest in this subject on the periphery of science. Levin, coming from the realm computer modeling and genetics, attracting the most modern methods absent from predecessors, in fact returns this direction to the biological mainstream. At the heart of it enthusiasm lies in the belief that electricity represents basic physical phenomenon, and evolution could not but use its in fundamental processes, such as the development of the body. By changing the transmembrane potential of cells, a scientist can give a command tadpole tissues to grow an eye in a predetermined area body. On the wall of his laboratory is a photograph of a six-legged frog. Additional limbs appeared in her solely as a result of effects on electrical biocurrents. Unlike neurons, ordinary cells are not able to be excited, but can consistently transmit signals almost throughout the body through slotted contacts. If the planaria has a tiny worm that can regenerate, cut off the tail, from the incision area will go a request to the head in order to make sure that it is in place. Block the transmission of this information, and instead of the tail should grow head. Manipulating various ion channels defining electrical properties of cells, scientists in their experiments got worms with two heads, two tails and even worms unusual design with four heads. According to Levin, almost he was always told that his ideas should not work. He relied on her intuition, and in most cases she did not fail. From these attempts are still very far from full knowledge of how to restore limb in humans. While people with disabilities can only rely on improvement of dentures. However in a unique laboratory Tufts Universities are looking for something even more fundamental: like genetic code, Levin believes, must exist bioelectric code connecting gradients and voltage dynamics membranes with anatomical structures. Having understood it, you can will not only control regeneration, but also affect growth tumors. Levin considers them as a consequence of cell loss body shape information and cancer research is included the number of tasks in his laboratory. As is often the case, various with mind processes can have a single nature. If the bioelectric code really stands behind the construction of various organs of the body, its unraveling can shed light on two crucial issues at once, facing humanity.
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