Antifreeze Proteins help Notothenioid fish survive in icy Water

Antifreeze Proteins help Notothenioid fish survive in icy Water

A new research team has recently discovered that several species of Antarctic notothenioid fish possess the ability to live in cold waters by producing proteins similar to antifreeze. The protein keeps pieces of ice inside the fish from getting larger. However, the same protein does not allow the ice to melt during warmer climatic conditions.

These protein-bound ice crystals that accumulate inside their bodies keep the ice from melting. It was also found that not all fish that live in Antarctica have this feature; it is mostly found in Notothenioid fish.

The team found that when the antifreeze proteins attach to a piece of ice, either inside of the fish or in a larger solution of water, it keeps the ice from melting even when the ice is heated beyond its normal melting point.

Ice that remains solid beyond its normal melting point is called "superheated" ice. According to researches, this may be the first-ever discovered case of superheated ice found in nature, according to the researchers.

The study has been done in collaboration between researchers from the University of Oregon and the University of Illinois. Paul Cziko and the rest of the team spent most of the past two years studying Antarctic ice fish, such as the Antarctic toothfish, to learn everything possible about how the fish survive in freezing waters.

The antifreeze protein was first developed approximately 20 million years ago and was discovered last year. Professor Chi-hing Christina Cheng, one of the researchers, mentions that currently the team is trying to figure out how having small pieces of ice inside the fish affects them.

Paul Cziko said these pieces of ice might be similar to blood clots in human body. He said, "Since much of the ice accumulates in the fishes' spleens, we think there may be a mechanism to clear the ice from the circulation".

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