The Insane Biology of: The Axolotl

In Aztec mythology the legend of the five sons is the myth of the creation of our world the dawn of the fifth son caused the era in which humans were created and is the era in which we currently live according to the myth this sun was created by the gods but could not move through the sky that not without sacrificial food the gods themselves were the first to be sacrificed to the setting sun the tradition of human sacrifice that the Aztecs would later follow the god shalottal however they did not want to be sacrificed to To evade detection, he transformed into other forms, first into the corn plant, then into the agave plant and finally into the aquatic monster, the

axolotl

.

When he was found, his brother Ketzel Koat spared his life, but banished him to live forever in darkness like an

axolotl

today. The aquatic monster is believed to still contain the spirit of a god. Axolotls are a type of salamander found only in the Sochi Milko Lake area outside Mexico City, near the ancient capital of the Aztecs, Tenochtitlán, and beyond its spiritual ties. Axolotls are unlike any other salamander. They live permanently in water and, in fact, live permanently in their juvenile form, never maturing into their adult body, a tadpole forever and, in addition to their ability to defy age, the axolotl can regenerate almost any part of its body from missing limbs, tails, organs, parts of the eye and even parts of its brain For hundreds of years, the axolotl has been fundamental to our understanding of how our own organs develop and function.

Its unique physiology holds the answers to many of our most pressing biological questions and we now hope to crack the code on its regenerative superpowers. One day we will be able to harness them for ourselves, but with only a few hundred kilometers of waterways left of its natural habitat, The axolotl is on the verge of total annihilation in the wild and time to unlock these mysteries is running out. Why is the axolotl so different from any other vertebrate? What exactly is it about their unusual physiology that makes them the most important amphibian known to science? Axolotls are members of the tiger salamander species complex and evolved relatively recently compared to other salamander species in the In this region they grow to be about 23 centimeters long and come in a variety of colors and, unlike almost all Other salamanders are neotenic, meaning they maintain juvenile characteristics until adulthood.

They never undergo metamorphosis, meaning they remain aquatic and never venture onto the land they maintain. their feathery external gills and caudal fins and lack movable eyelids When they were first shipped from Mexico to noted French zoologist Augusta Dumaril in the 1860s, he was certain that the axolotls were larvae of an unknown type of salamander until six months later. , when their specimens reproduced very unexpectedly and because the adult stage of animals is defined by sexual maturity, these reproductive axolotls had to be adults. The strangeness of the axolotl was just beginning to reveal itself. Overall, retaining juvenile traits seems like a cute but strange thing to happen in At first glance, in the wild it looks like an entire species whose growth has been permanently stunted, but although axolotls are one of the only salamanders that remain in their juvenile form, Sometimes you can find other salamanders in the region doing the same with some individuals who stay in the water for their entire lives.

At first naturalists didn't know what to make of this phenomenon, but looking at where these salamanders lived began to give a clue as to why this may be selected in nature. All of the Mexican lakes where they are found have a few key things in common: first , they are all large, relatively permanent bodies of water, at least that is how they were before human intervention; second, the lakes are surrounded by desert and in many cases are the only permanent body of water in the region; and, third, all of these lakes historically did not have large predatory fish.

Salamanders in these lakes sometimes or always fail to mature to adulthood because these lakes are the only suitable habitat amidst a harsh, dry terrestrial environment. Salamanders normally metamorphose to take advantage of both waters. and land, but only if the land is somewhat moist, but staying in water forever is a strategy that only works without major predators lurking beneath the surface along with certain pH, temperature, and altitude requirements. These Mexican lakes simply fit the bill giving the salamanders a unique ability to thrive there. For a time it was thought that the axolotl never undergoes metamorphosis that its neoteny is a permanent feature of its

biology

, although this may be true most of the time. , is not true all the time as French zoologist Dumarill found out in 1865, when his axolotl specimens gave him an even bigger surprise.

To his surprise, some of the individuals under his care transformed into their adult terrestrial form: they resembled tiger salamanders, but different enough to still be considered. its own unique species dumaril searched for the rest of its life for an explanation as to why these axolotls transformed but died before getting the answer, but in the early 20th century axolotl transformation was again at the forefront of research interests during At this time, researchers were looking at thyroid gland tissue as a mechanism for amphibian metamorphosis and the axolotl was the most suitable animal to clearly demonstrate its effect. When axolotls were fed thyroid tissue from cattle, the axolotls were They metamorphosed by losing their external gills, shedding their larval skin, and basically venturing onto land. thyroid tissue is a real-life moonstone for the axolotl;

In other cases, axolotls can transform when they are forced to breathe air, but this is stressful for the animal and takes much longer; However, it may be the reason why some in captivity have unexpectedly metamorphosed the discovery of transforming axolotls. a central role in the path towards our understanding of thyroid hormones such as thyroxine, which was first isolated in 1915 and synthesized in 1926. This marked the beginning of what would become the axolotl's immense contribution to medical research . All organisms have some level of regenerative capacity for some. Animal regeneration is only part of life, flatworms and hydras can regenerate their entire body even from a small part of their original self.

Starfish, octopuses or even crabs can lose an arm and grow back without much problem, but all these animals share something in common, they are all invertebrates in vertebrates like us, regeneration is practically limited to growing skin. or scar tissue over a wound, except for our liver, we cannot regenerate our organs or our limbs, in fact, almost no vertebrates can regenerate much further than we can. That is, with the exception of the axolotl and the other members of the order salamanders, the only other vertebrates that can recover limbs are frogs, but frogs lose the ability once they fully convert into their adult form, the axolotl retains its ability to regenerate throughout its life in the same way that an axolotl regrows a limb begins with cells that survive the limbs once the limb has been cut off or a blood clot has been lost quickly stops bleeding in the cut and a layer of cells covers the amputation area this part is not that different from the way we would heal Then, over the next few days, the cells beneath the epidermis begin to divide rapidly forming a cone-shaped structure known as blastoma, also called regeneration bud.

The blastoma is what holds the key to regeneration. It is where regular bone cartilage or muscle cells dedifferentiate. which means they lose their identity and transform back into stem cells. They slowly begin to reform the bone skin and veins much like stem cells would when the animal first develops into its egg, as the blastoma cells continue to divide, nerves and blood vessels follow them. they connect. On the rest of the body, the limb eventually grows back completely looking like an exact copy of the limb that was lost, and while total limb regeneration is quite impressive, axolotls are also capable of doing something that seems absolutely impossible. : regrow parts of your brain.

In mammals like us and indeed most vertebrates, neurons generally only grow in the embryonic stage. Any neurogenesis that occurs in adulthood is quite limited. If the brain is damaged in adulthood, it generally cannot regenerate new neurons, blood vessels or tissues, but somehow doing so is not possible. problem for the axolotl by dedifferentiating stem cells, they can add new neurons throughout their life and can regenerate the spinal cord and parts of the brain after injury. Salamanders are the only four-legged vertebrates that can transform normal cells back into stem cells, allowing them to grow back into new tissue.

This may seem like a superpower, but the axolotl doesn't actually have special regeneration genes to do this. , they are simply regulating their genes differently than other animals, this fact gives scientists hope that we still have this ability locked inside. shows us an ability that, if unlocked, could greatly benefit people suffering from certain organ failures, limb amputation or severe burns, while we still do not know the exact mechanisms that allow the axolotl to dedifferentiate cells, some of the components key are beginning to be revealed that many of them resemble the cells and molecules that are already working in our bodies.

One way to learn what molecules and cells are necessary for an axolotl to regenerate is to look for molecular adjustments that make them lose their regenerative capacity, for example, macrophages. It is known to be critical during inflammation in response to injury in many animals and has previously been linked to regeneration, so researchers found that injecting a drug that kills macrophages into the limb of an axolotl before amputation does scar tissue forms instead of regenerating. that macrophages, a type of cell that we readily have, are an important component for regeneration. The researchers similarly discovered that a protein called transforming growth factor beta is key in axolotl regeneration, a molecule that is also essential in preventing scar tissue in injured human embryos during the first trimester and.

In addition to this, the researchers also have found that both mice and humans can regenerate a partially amputated finger or toe, although humans lose this ability as they age. Researchers believe this is due to a type of stem cell found under the nail that normally helps. nails grow perpetually, they now think that these cells could also be a remnant of a time when our regenerative abilities were stronger. The regrowth of the fingers of the mice studied depends on two specific types of proteins called wnt and fgf2 proteins and certain proteins from signaling pathways and pathways that appear to all be the same as those in salamanders during regeneration, all of this suggesting that we can partially retain the same regeneration abilities as the axolotl's abilities that could one day be reawakened.

For this reason, the axolotl is one of the most incredible and most important research animals in science, as well as becoming a beloved pet in freshwater aquariums around the world, and yet they are facing almost complete annihilation. In the wild, the axolotl's conservation story is unique and if we are not careful we risk losing one of the most important animals. incredible creatures on earth the wild axolotl is on the verge of extinction its population has decreased exponentially in recent decades in a 1998 study it was reported that around 6,000 individuals lived per square kilometer in its habitat in 2015 only 35 individuals were found per square kilometer were predicted to become extinct in the wild by 2020, although they have barely escaped this fate.

No one knows exactly how many are left now, but the numbers are frightening today. The axolotl is found naturally in a single place like Sochi Milko, but the modern bypass of this lake is more like a series of small canals, it is a ghost of what it used to be and represents only two percent of thehuge original wetland system. Centuries ago this area contained several large lakes that were home to many Mesoamerican cultures including the Teotihuacans, Toltecs and later the Aztecs. At the time of the Spanish conquest in 1519 the size of these lakes would have covered much of the modern Mexico City, due to its naturally shallow waters and freshwater springs in South Lake Sochi Milko, was the center of Chinampa agriculture.

In the centuries before the arrival of the Spanish, these artificial islands created an extensive network of canals. The ancient cities here in some ways were very similar to today's Venice. Here the axolotl thrived alongside humans, but over time the area's population grew and grew. and eventually all lakes were drained with the exception of lake sochi milko to prevent flooding and allow for urban expansion. What remains of Lake Sochi Milko today is highly polluted, full of dangerous algae blooms and large invasive fish that compete with and eat the axolotls. It is not surprising that the axolotl has almost disappeared there, and yet in laboratories around the world the axolotl abounds.

They have even been called the white mice of amphibians, as they are ideal for research and are easy to breed in the laboratory. They are the most distributed. amphibian in the world, so you may wonder if the axolotl is thriving in aquariums and laboratories, what is the problem, unfortunately, laboratory colonies are not staying healthy, these captive populations are becoming inbred and lack the genetic diversity that protects from disease To help mitigate this, scientists have crossed axolotls in captivity with a similar species, the tiger salamander, but this has left many laboratory specimens with a large number of foreign genes, meaning they are no longer exactly the same as wild axolotls.

One proposed solution to the decline of wild axolotls is to simply reintroduce some of the captive population into the wild, but until the lake is cleaned up, returning them would be a death sentence and, despite the efforts of some scientists and conservationists such as Sochi Milko, becoming clean and healthy any time soon seems unlikely.By reintroducing them to their original habitat, some scientists have a different idea to give the axolotls a new home. A suitable site has been identified near the National Autonomous University of Mexico. A freshwater lake has been born from an abandoned quarry and researchers are now using it as an ecological resource. research site, dozens of axolotls have been released here and are tracked using radio transmitters.

Over time, it is hoped that these research subjects will breed here and a new type of semi-wild population may be born, perhaps with the introduction of wild-caught axolotls alongside those raised in the laboratory. Their genetic diversity could improve and although it is a different ecosystem to the swampy canals that evolved, places like this may be the best option for the long-term survival of these magnificent creatures. Mexico is one of the countries with the greatest biodiversity in the world. The world finds Brazil, Colombia and Indonesia at the top of the biodiversity list with thousands of unique endemic species.

It is estimated that more than 10 of all the world's species live in Mexico, which is why it is considered a mega diverse country. The axolotl is far from the only notable native species that Mexico has to offer: the Mexican prairie dog, the Owls, the Mexican wolf, the rarest subspecies of wolf in North America, and the American bison, the largest land animal in the Americas, are amazing creatures that live on the grasslands. of Mexico's grasslands, an ecosystem that can be easy to overlook, is in fact teeming with biodiversity. The number of different types of grasses there are is comparable to the number of different types of trees in a rainforest.

Personally, I didn't know much about this amazing ecosystem. Before seeing my wild backyard on the curiosity stream, the Janos Biosphere Reserve episode caught my attention, especially since I live in Texas and this ecosystem is actually in my backyard. Other episodes explore the unexpected wildlife of New York City or the stunning national parks of Argentina. Follow the locals. ecologists and scientists as they show us the hidden wonders of wildlife that exist around us. Curiosity Stream is a streaming platform with thousands of high-quality documentaries like this and now Curiositystream is partnering with us to offer an incredible deal by signing up for Curiositystream. now also get a subscription to nebula nebula is a streaming platform created by me and several other YouTube educational content creators.

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