A thermal hysteresis-producing xylomannan glycolipid antifreeze associated with cold tolerance is found in diverse taxa

Abstract

The presence of large-molecular-mass, thermal hysteresis (TH)-producing antifreezes (e.g., antifreeze proteins) has been reported in numerous and diverse taxa, including representative species of fish, arthropods, plants, fungi, and bacteria. However, relatively few of these antifreeze molecules have been chemically characterized. We screened diverse species by subjecting their homogenates to ice-affinity purification and discovered the presence of a newly identified class of antifreeze, a xylomannan-based TH-producing glycolipid that was previously reported in one species of freeze-tolerant Alaskan beetle. We isolated xylomannan-based antifreeze glycolipids from one plant species, six insect species, and the first frog species to be shown to produce a large-molecular-mass antifreeze. (1)H NMR spectra of the ice-purified molecules isolated from these diverse freeze-tolerant and freeze-avoiding organisms were nearly identical, indicating that the chemical structures of the glycolipids were highly similar. Although the exact functions remain uncertain, it appears that antifreeze glycolipids play a role in cold tolerance.

Advances in physiological and molecular aspects of plant cold tolerance

“…Research about the mechanism of ice initiation in plants has greatly decreased recently because of its essential role in specific aspects of cold hardiness (Gusta et al 2009;Aryal & Neuner 2010;Hacker et al 2011;Walters Jr et al 2011). Ice formation may take place either in the intracellular or extracellular spaces depending on the cooling conditions (Guy 1990).…”

Antifreeze proteins in the primary urine of larvae of the beetle Dendroides canadensis (Latreille)

“…In response to decreasing temperature and reduced photoperiod in the autumn, D. canadensis cease feeding and drinking, clear gut contents and synthesize AFPs, as well as antifreeze glycolipids and glycerol (Olsen and Duman, 1997;Duman et al, 2010;Walters et al, 2011). During warm periods in the winter and in early spring when snowmelt occurs, the larvae appear to drink, but this has not been conclusively demonstrated.…”

The many roles of fats in overwintering insects

“…Antifreeze proteins and glycoproteins are perhaps the most celebrated of the molecules associated with low-temperature tolerance and have been well-characterised in insects (Doucet et al, 2009;Duman, 2015;Bar Dolev et al, 2016). Recently, a xylomannan glycolipid with activity similar to that of well-known antifreeze proteins was identified in a freeze-tolerant Alaskan beetle (Walters et al, 2009); these glycolipid antifreeze proteins have subsequently been found in a range of overwintering insects (Walters et al, 2011). These glycolipids consist of a repeated xylose-mannose backbone with fatty acyl moieties attached (Fig.…”