Limb Regeneration Is Not Limited To Salamanders
May 17, 2021 at 8:15 p.m.
By Max [email protected]
His thoughts were included in a recent issue of the New Yorker. Levin’s work involves converging biology with computer science. He uses electrical signals to stimulate cells without involving the organism’s genome and by altering what he believes is possible to control growth. Levin argues that the cells in our bodies use bioelectricity to communicate and to make decisions among themselves as to what they will become.
Mastering the code of electrical charges in body tissues will give scientists unprecedented control over how and why they grow. Levin is convincing a number of biologists of his theory and that it is possible to decipher, and even speak, the electrical code.
His work follows studies of the reality of bioelectricity that began in the 20th century. In 1909, it was discovered that larval salamanders regenerate faster when electricity courses through their aquarium water.
In the following decades, researchers measured distinct bioelectrical patterns associated with development and wound healing. Eventually, the biologists came to understand that electricity is integral to cellular life.
Cell membranes contain tiny valves known as ion channels, which maintain the cell’s negatively charged interior and positively charged exterior by allowing charged atoms called ions to flow in and out. Cells employ the bioelectrical system as an intracellular internet, and use it to build intricate and expansive communication networks that control gene transcription, the contraction of muscles, and the release of hormones.
In 2016, Levin and his team injected cancer – causing rRNA into frog embryos, and found that injected areas first lost their electrical polarity, then developed tumor-like growths. When the researchers counteracted the depolarization, some of the tumors disappeared.
According to Levin, the cancer cells had lost the thread of the wider conversation, and begun to reproduce aimlessly, without cooperating with their neighbors. Once communication had been restored, they were able to make good decisions again.
Salamanders
Salamanders are a group of amphibians typically characterized by a lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten present-day salamander families are grouped together under the order Urodela. Most salamanders look like a cross between a lizard and a frog. They have moist, smooth skin like frongs and long tails like lizards.
There are several species of salamanders including newts that will regenerate limbs that are amputated. Experiments have shown that if restoration of a limb is to occur (1) limb tissues must injured, (2) a wound epidermis, free from underlying dermis, must cover the amputation surface and (3) nerves must be present in sufficient quantity at the level of amputation. If any of the three are prerequisites is absent, regeneration will not occur. The exact roles of injury, the wound epidermis, and nerves in the initiation of regeneration are not understood.
Regeneration is not limited to salamander species, many other larval and adult animals are able to do the same after transection or amputation and this usually restores the structures that were removed. If a planarium worm is transected, the head fragment regenerates tail structures, whereas the tail fragment grows a new head. Newts and other salamanders can regenerate fully functional limbs, organs and tissue, including heart muscle, components of its nervous system and the lens of its eye. The molecular basis is complicated and involves growth zones and local cell interactions.
Newts are members of the Salamander family, all newts are salamanders but not all salamanders are newts. Strangely, the newt genome is 10 times larger than the human genome.
Final Thoughts
We continue to learn more and more about how wounds learn or know how to heal and how tissues of unborn babies differentiate and take shape without direction from a brain. It all suggests that limbs and tissues besides the brain might be able to remember, think and act. Someday, perhaps even our species will be able to regenerate any of its limbs or organs. Determining the mechanism is the first place to begin the journey.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. His new book “Science Snippets” is available from Amazon and other book sellers. It contains a number of previously published columns. He can be reached by email at [email protected].
His thoughts were included in a recent issue of the New Yorker. Levin’s work involves converging biology with computer science. He uses electrical signals to stimulate cells without involving the organism’s genome and by altering what he believes is possible to control growth. Levin argues that the cells in our bodies use bioelectricity to communicate and to make decisions among themselves as to what they will become.
Mastering the code of electrical charges in body tissues will give scientists unprecedented control over how and why they grow. Levin is convincing a number of biologists of his theory and that it is possible to decipher, and even speak, the electrical code.
His work follows studies of the reality of bioelectricity that began in the 20th century. In 1909, it was discovered that larval salamanders regenerate faster when electricity courses through their aquarium water.
In the following decades, researchers measured distinct bioelectrical patterns associated with development and wound healing. Eventually, the biologists came to understand that electricity is integral to cellular life.
Cell membranes contain tiny valves known as ion channels, which maintain the cell’s negatively charged interior and positively charged exterior by allowing charged atoms called ions to flow in and out. Cells employ the bioelectrical system as an intracellular internet, and use it to build intricate and expansive communication networks that control gene transcription, the contraction of muscles, and the release of hormones.
In 2016, Levin and his team injected cancer – causing rRNA into frog embryos, and found that injected areas first lost their electrical polarity, then developed tumor-like growths. When the researchers counteracted the depolarization, some of the tumors disappeared.
According to Levin, the cancer cells had lost the thread of the wider conversation, and begun to reproduce aimlessly, without cooperating with their neighbors. Once communication had been restored, they were able to make good decisions again.
Salamanders
Salamanders are a group of amphibians typically characterized by a lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten present-day salamander families are grouped together under the order Urodela. Most salamanders look like a cross between a lizard and a frog. They have moist, smooth skin like frongs and long tails like lizards.
There are several species of salamanders including newts that will regenerate limbs that are amputated. Experiments have shown that if restoration of a limb is to occur (1) limb tissues must injured, (2) a wound epidermis, free from underlying dermis, must cover the amputation surface and (3) nerves must be present in sufficient quantity at the level of amputation. If any of the three are prerequisites is absent, regeneration will not occur. The exact roles of injury, the wound epidermis, and nerves in the initiation of regeneration are not understood.
Regeneration is not limited to salamander species, many other larval and adult animals are able to do the same after transection or amputation and this usually restores the structures that were removed. If a planarium worm is transected, the head fragment regenerates tail structures, whereas the tail fragment grows a new head. Newts and other salamanders can regenerate fully functional limbs, organs and tissue, including heart muscle, components of its nervous system and the lens of its eye. The molecular basis is complicated and involves growth zones and local cell interactions.
Newts are members of the Salamander family, all newts are salamanders but not all salamanders are newts. Strangely, the newt genome is 10 times larger than the human genome.
Final Thoughts
We continue to learn more and more about how wounds learn or know how to heal and how tissues of unborn babies differentiate and take shape without direction from a brain. It all suggests that limbs and tissues besides the brain might be able to remember, think and act. Someday, perhaps even our species will be able to regenerate any of its limbs or organs. Determining the mechanism is the first place to begin the journey.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. His new book “Science Snippets” is available from Amazon and other book sellers. It contains a number of previously published columns. He can be reached by email at [email protected].
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