MicrobeWorld

Scientists in the US have discovered a new class of biological antifreeze molecules - the first that do not contain proteins. The antifreeze, extracted from an Alaskan beetle capable of surviving at -60°C, consists of linked mannopyranose and xylopyranose sugars, termed xylomannan, associated with a lipid.

Large molecules that cause thermal hysteresis - a difference between the melting and freezing points of a solution - have been identified in many organisms that survive in the cold, from Antarctic fish to plants and bacteria. In all cases identified so far, thermal hysteresis appears to be caused by proteins, known as antifreeze proteins or AFPs.