TRACKING THE PROFILE OF A SPECIFIC ANTIFREEZE PROTEIN AND ITS CONTRIBUTION TO THE THERMAL HYSTERESIS ACTIVITY IN COLD HARDY INSECTS

This study summarizes some important new directions in research on ant ifreeze protein biosynthesis and regulation. It describes the recent d evelopment and availability of essential biochemical and cellular tool s that make possible more direct cellular investigations, and an asses sment of the relationship between thermal hysteresis protein (THP) lev els and antifreeze activity (both thermal hysteresis and recrystalliza tion inhibition [RI]). These tools include: 1) the isolation of a spec ific THP of high activity designated Tm 12.86), and an additional endo genous activating factor of this antifreeze protein; 2) the ability to track the cellular and secretory patterns of Tm 12.86 immunologically ; 3) the use of an in vitro fat body cell culture system for direct in vestigation of cellular events, and, 4) a means of quantifying RI beha vior of purified Tm 12.86, and samples of unknown concentrations of TH Ps, to provide a more sensitive detection method for antifreeze activi ty at scaled down values associated with the in vitro system. In combi nation, these studies indicate that the adaptation mechanisms contribu ting to the overall antifreeze protein response in a cold hardy insect involves a complex interaction between antifreeze proteins and endoge nous activators of these proteins. With the availability of these key tools, the details of a precise and seasonal regulation of these antif reeze protein/activator interactions, which ultimately generate an eff icient cold hardy response, now have the potential to be worked out.