Cienciaes.com: The snake’s venom. venomics. We spoke with Juan José Calvete Chornet

2021-03-03 10:06:13

An article recently published in Science talks about the evolution followed by three species of cobras until they independently developed a curious but very effective defense system. When they feel threatened, instead of biting the victim and inoculating the poison, they spit it into the eyes of the person or animal that threatens them with great precision, causing intense pain, which makes it possible for them to escape. This example of what is known as “convergent evolution” has allowed us to get closer to the world of venomics, a scientific discipline in which our guest works today in Talking with Scientists, Juan José Calvete Chornetresearcher of Evolutionary and Translational Venomics Laboratory in it Institute of Biomedicine of Valencia.

Venomics, the union of “poison” and “omics”, is a way of doing science that allows us to study poisons as a whole, instead of doing it by individually analyzing the molecules that compose them. Thus, venomics uses genetic techniques to analyze the genes of animals that generate poisons (genomics), studies the molecules of ARN that read the information encoded in those genes and copy it to transport it to the protein manufacturing sites (transcriptomics), and analyze the proteins that make up the toxins in the venoms (proteomics). All this allows us to know not only the composition of the poisons and their toxicity, but also facilitates knowledge of the set of molecules and interactions existing in the poisons that can be used to prepare antidotes and drugs. That’s right, some components of poisons have opened the doors to the development of certain medicines that are used to control blood pressure, that prevent the formation of thrombi, etc.

Poisons abound in nature and poisonous creatures too, although, as he says Juan Jose Calvete, you have to differentiate between poisonous and toxic. A poisonous animal is one that uses its poison to attack and capture its prey, unlike others that use the toxicity of the substances they secrete to defend themselves.

In nature there are more than 100,000 species that produce some type of toxic or poisonous substance. Among all the poison-producing animals, snakes are a special category. Many of them, it is not even known if they are poisonous or not. Some, like vipers, are armed with retractable fangs that can be extended forward to bite and inject venom into their prey; there are about 300 species of this type worldwide. Another set is made up of cobras, mambas and other related species, these have fixed teeth with which they inject venom into their prey. But a large number of them, belonging to the group of snakes, that is, snakes, contain in teeth located at the bottom of the mouth the ability to inoculate some substance to kill the prey they try to swallow.

Our guest says that biting a human being and injecting it with venom is not useful work for a snake, or even a cobra. As prey we are too big, but as predators, on the other hand, we are dangerous for them. Many of the encounters with these snakes occur by chance, when humans and snakes cross paths in the middle of nature. In this case, the cobra rises, flattens the neck vertebrae to appear larger, and snorts as a warning. Its intention is not to attack but to defend itself, although its deadly bite injects a neurotoxin that paralyzes the muscles and diaphragm, causing the victim to suffocate.

Juan José Calvete Chornet explains during the interview the different types of venom secreted by snakes, some are neurotoxic, such as the one mentioned in the cobra, others act on blood circulation and the cardiocirculatory system either causing thrombi that paralyze the prey or, otherwise, causing hemorrhages that bleed them out. The evolution of predators and prey has developed a kind of arms war in which species that have a greater ability to immobilize their prey and prey that are more resistant to attacks have been favored. One of these paths seems to have had humans as a partner because data indicates that the evolution of certain venomous snakes has followed a path parallel to the expansion of hominids.

Our guest teaches us how antidotes for snake venoms are obtained and the difficulties involved in making them. He explains how a mammal’s body reacts to venom and how antibodies can be generated to inactivate it, if the dose is not too large and the animal has time to counteract its effects.

As revealed in the article “Convergent evolution of pain-inducing defensive venom components in spitting cobras”, published in Science, signed by TD Kazandjian of the Liverpool School of Tropical Medicine in the United Kingdom and by other authors, including Juan José Calvete Chornet, at least three species of spitting cobra developed the ability to shoot venom into their eyes independently throughout their evolution.

I invite you to listen to Juan José Calvete Chornetresearcher of Evolutionary and Translational Venomics Laboratory in it Institute of Biomedicine of Valencia

Reference:

TD Kazandjian et al., Convergent evolution of pain-inducing defensive venom components in spitting cobras Science Jan 22, 2021: Vol. 371, Issue 6527, pp. 386-390 DOI: 10.1126 / science.abb9303