Living Organisms Need AntiFreeze Proteins to Survive in Cold

Plants and animals living in cold climates have natural antifreeze proteins (AFPs) that help them to survive, according to a new study.

A team of international researchers from the U.S., Israel and Canada have demonstrated how living organisms use their AFPs to prevent ice growth and crystallization of organic fluid matter. AFPs help plants and animals to survive in the cold, which would otherwise suffer from damage due to frost and might even die.

For their study, the research team examined the antifreeze protein of the yellow mealworm. The protein is effective in arresting ice growth that is 100 times greater than the potency of fish and plant AFPs. Scientists biochemically created a fluorescent marker version of the AFP in order to observe them under a microscope lens.

The protein was injected into custom-designed microfluidic devices with minute diameter channels. The microfluidic devices were placed in cooling units engineered with a temperature control at the level of a few thousandths of a degree. This was done so as to allow the ice crystals of 20 to 50 micrometers to be grown and melted controllably, all under microscopic observation.

Using this research work, scientists were able to show that ice grown and incubated in an antifreeze solution remains coated with protein and protected in subzero environments. They also showed that the AFPs bind ice directly and strongly enough in order to prevent ice growth even if there is no further presence of protein in the solution.

Researchers insist that the findings are significant, as the antifreeze proteins could be used in various fields. For instance, fish AFPs are already used in low-fat ice cream to prevent ice recrystallization and maintain a soft, creamy texture.

The AFPs can also be used in medicine to improve the quality of sperm, ovules and embryos stored in a frozen state. They can be used in cryosurgery and in agriculture, said the researchers.

The findings of the study appear in the journal Proceedings of the National Academy of Sciences.