Snakes Develop Ability to Resist Their Own Venom, Study Reveals

Scientists have discovered how snakes' resistance against their own venom has evolved over time using cutting-edge technology. The study which was carried out at the University of Queensland, Australia found that this phenomenon results from genetic changes in nerve cell receptors.

Snake venom contains neurotoxin (nerve-attacking chemicals) that is capable of killing mammals in a split of minutes. Not only does the venom kill mammals but it kills other snakes too.

(Photo : Pixabay)

The Discovery of the Resistance

Two researchers, Professor Bryan Fry and Ph.D. student Richard Harris, both of the University of Queensland in Australia, have found that genetic changes in nerve cell receptors result in snakes' ability to resist venom from the bite of other snakes.

They said changes at this genetic level mean receptor cells carry the same electrical charge as the venom. It implies that when the venom tries to attack the cells it is repelled. The concept can be likened to trying to bring two positive ends of a magnet together.

The study explained that the genetic mutations enable certain species, such as the mole snakes, Burmese pythons, and other southern stiletto snakes to repel a particular neurotoxin found in snake venom.

The researchers found that a single gene mutation allows vulnerable snakes to develop resistance against alpha-neurotoxins. It's not only the vulnerable snakes that develop this resistance, even the predator snakes also do.

The team identified similar mutations in predator snakes that help to protect themselves from their own deadly venom.

Cobras and kraits who prey on other snakes evolved their venom in a manner that the alpha-neurotoxins have positively charged surface sites.

The sites support the venom to bind with particular target nerves with negatively charged receptors. It brings opposite sides of magnets together. 

In the same vein, Burmese pythons have evolved genetic mutations to escape this type of interaction. They have changed the amino acid of their target receptor from negatively to positively charged.

This interaction with alpha-neurotoxins becomes repulsive thereby deterring the venom rather than binding. Fry added that they searched through sequences and are sure that it has the same repulsive effect in other species. 

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(Photo : Ray Bilcliff)

Reason The Study Was Successful 

This study was successful as a result of developing artificial nerves with or without the genetic mutations to observe their interactions with the venom.

Cutting-edge technology, biosensors, was deployed to measure almost any interactions between molecules.

Using the equipment, they observed a synergistic effect that enhances resistance by charge reversal of two sites together.

As it is, it lowers the vulnerability to alpha-neurotoxin by creating a stronger repulsive charge interaction. On his part, Harris said, "That was one thing we didn't expect, this synergistic effect was quite a surprise when looking at the data.

Regardless of how amplified this resistance is, the predator's venom will perhaps adopt again. The nerve receptors have many sites of interactions and have many potential binding sites for toxins.

Harris said they are looking for other neurotoxins that have the capacity to bind to different parts of the receptor, and consequently finding their way around this particular type of resistance.

Fry emphasized that every benefit comes with a tax. That is a fitness disadvantage that explains why it's not every species of snake develops resistance. If not at extreme risk, the genetic mutation may do more harm than good.

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