Hemolymph ice nucleating proteins from the New Zealand alpine weta Hemideina maori (Orthoptera: Stenopelmatidae)

We report measurements of the supercooling point of the hemolymph of the freeze-tolerant New Zealand alpine weta Hemideina maori Hutton (Orthoptera; Stenopelmatidae). Dilution curve and supercooling points following ultrafiltration argue that the ice-nucleation agents present are proteinaceous. We also report dynamic light-scattering measurements leading to hydrodynamic diameters of large molecules found in the weta hemolymph. The measured diameters agree well with theoretical estimates for sizes of ice-nucleating proteins corresponding to the measured supercooling points.