104.4 Sunday, Jan. 6 The goldenrod gall fly’s liquid little secret: 3-acetyl-1,2-diacyl-sn-glycerols are associated with natural survival of intracellular freezing in Eurosta solidaginis MARSHALL, K.E.*; THOMAS, R.H.; ROXIN, A.; CHEN, E.K.Y.; BROWN, J.C.L.; GILLIES, E.R.; SINCLAIR, B.J.; University of Western Ontario; University of Western Ontario; University of Toronto; University of Western Ontario; University of Western Ontario; University of Western Ontario; University of Western Ontario firstname.lastname@example.org
The fat body cells of the goldenrod gall fly Eurosta solidaginis have the unusual ability to naturally withstand intracellular ice formation (IIF). To date, no unique compounds associated with natural IIF survival have been identified for any animal. Here we show that E. solidaginis seasonally synthesizes an unusual class of neutral lipid, 3-acetyl-1,2-diacyl-sn-glycerols (acTAGs). acTAGs are accumulated in preparation for winter and at their peak concentration comprise over 36% of the insect’s neutral lipid pool while long-chain TAGs (lcTAGs) comprise only 17% percent (by molarity). The acTAGs have a low melting point (-17 °C), and are therefore expected to remain liquid at temperatures where the cells freeze. These acTAGs are not found in other cold tolerant insects, and are not present in the Solidago spp. host or other members of the gall community. In addition, the amount of acTAGs increases when repeatedly frozen, and when added to saline, acTAGs lower the melting point of the resulting emulsion. We suggest these properties are consistent with a role as a candidate molecule for IIF survival.