Recent developments in cryopreservation of stallion semen with special emphasis on thawing procedure using thermal hysteresis proteins

While the first attempt to cool and preserve stallion semen was done 200 years ago (by Spallazani) and the first pregnancy achieved with frozen-thawes stallion semen almost 40 years ago (Barker & Gandier, 1957), frozen stallion semen has not been used widely, mainly because of its association with low fertility.

Microscopic Pattern of Ice Crystal Growth in the Presence of Thermal Hysteresis Proteins

This study examines the effect of thermal hysteresis proteins (THPs) from the winter flounder (Psuedopleuronectes americanus) on the ice-water interface morphology during freezing of aqueous solutions. Experiments were performed using a directional solidification stage, and the development of the two-phase interface was observed through a microscope and recorded by a video system. Unusual ice crystal morphologies were observed, including faceted ice crystal growth along the [1100] crystal plane; spicular or needlelike growth in the [1010] direction; and growth parallel to the c-axis, [0001], consisting of incorporated liquid inclusions bounded by hexagonal prism faces. The observed crystallographic structures can be explained as an effect of the interaction between the THPs and the primary prism faces of ice crystals. This results in an increase in the Gibbs free energy of these planes, followed by ice growth into the supercooled liquid adjacent to these faces.