2021-04-20

Research: The complexity of snake venom is determined by the diet of the prey

By yqqlm yqqlm

Christopher Parkinson, a professor in the Department of Biological Sciences at Clemson University’s School of Science, said: “It’s not the dietary habits that determine the difference in snake venom. This is a broad diet. If a snake eats 20 different mammals, then Its venom will not become very complicated. But if it eats centipedes, frogs, birds and mammals, its venom will be very complicated, because each component of the venom will affect the difference among the different animals the snake preys on. Things.”

Research: The complexity of snake venom is determined by the diet of the prey

Matthew Holding, the lead author of the paper, said: “Snakebite is a neglected tropical disease. In the United States, there are not many deaths, only about 8 people per year. But it can cause lasting damage such as nerve and tissue damage. Although we have good antivenoms, they can certainly do better.”

Holding collaborated with researchers from Clemson, Florida State University, Mexico and Brazil to study 46 species The venom and diet of North American Agkistrodon, which includes all venomous snakes living in the United States. Later, they used the dietary information of these species to understand why some venoms are very simple and some are very complicated.

The protein contained in the venom can make the prey incapacitated. The number of different proteins it contains reflects its complexity.

Research: The complexity of snake venom is determined by the diet of the prey(1)

“You can think of venom as The snake’s toolbox,” Holding said, “wrenches, sockets, and screwdrivers each have different purposes. Similarly, when the venom is injected into rats, lizards, centipedes, or any prey eaten by a snake, each protein has a different Function. Some snakes have simpler venom and fewer ingredients. Some have more. We want to understand why this is the case from an evolutionary perspective.”

For this, the researchers collected North American rattlesnakes and cotton A sample of the venom and venom glands of the mouth snake. They used next-generation sequencing technology to generate the largest viper proteome and venom transcriptome data set to date. Using natural history specimens, the researchers compared the complexity of the venom to the diet of snakes.

Research: The complexity of snake venom is determined by the diet of the prey(2)

“Have a specimen based on natural history Our prey database is crucial, because without these museum collections we would not be able to complete this work. Without snakes, we would not be able to establish a more phylogenetic framework to compare the diet and evolutionary history of snakes.” A researcher Christopher Parkinson pointed out.

Holding said that changes in the complexity of snake venoms are related to the phylogenetic diversity of snake diets–including the evolution of simple and complex venoms. The study shows that the degree of difference between prey species is critical to the evolution of the target venom, not just the difference between prey species or major taxa, regardless of their systematic evolutionary relationship.

Some previous studies used rough data to suggest that diet may have caused the difference in snake venom. This project used more than 250 snake venom gland genetic data, which is more intensive than any other research to date. The researchers also compiled a detailed prey database. Combining these data will help understand the causes of venom mutations.

Research shows that dietary diversity can predict the complexity of expression of three of the four largest venom gene families in viper venom. Serine proteases, metalloproteinases and phospholipases have a positive relationship, which means that the more diverse a snake’s diet, the more complex its venom. But diet does not have the same effect on C-type lectins. The diversity of food is responsible for 25% to 40% of the changes in the complexity of the venom.

“(For this) we asked new questions for other researchers to solve, such as why the relationship between C-type lectin and dietary diversity is different from other gene families, and what can explain the rest 3/4 of the change in the complexity of the venom, we can’t explain (to this),” Holding said.

Since snake venom-derived drugs are used to treat human heart disease, high blood pressure and blood clots, the more thoroughly scientists understand snake venom, the more likely it is to use it to make human drugs.