The roughened darkling beetle can produce a nonprotein antifreeze molecule in low temperatures. (Kent Walters/University of Notre Dame)
Insects exposed to subzero temperatures can adapt to the extreme climate to survive freezing temperatures, but until now, antifreeze molecules had not been isolated from freeze-tolerant animals. An NSF-supported study, published in the Nov. 24 issue of Proceedings of the National Academy of Sciences, describes a brand new type of antifreeze molecule isolated from the freeze-tolerant roughened darkling beetle (Upis ceramboides) by Kent Walters and colleagues at the University of Notre Dame.
Interestingly, the antifreeze molecule described by the research team differs from previously described factors in that it is not a protein, but a combination of saccharides and fatty acids, which are other types of biomolecules.
What does that mean? Size is one big difference. The exact size of this particular molecule is unknown, but the fact that it is small could prove beneficial. The chemical composition of the molecule could prove amenable to commercial production because small chains of sugars can be readily synthesized in the laboratory, making them cheaper and easier to manufacture than biologically assembled molecules.
Antifreeze molecules are present in many organisms including fish, insects, plants, fungi, and bacteria. "The most active known antifreeze proteins had been described in freeze-avoiding insects, allowing certain insects to survive temperatures below -60 C (-76 F)," said Walters. However, this is the first reported isolation of antifreeze from a freeze-tolerant insect (those able to survive freezing).
