CHARACTERIZATION AND LOCALIZATION OF THE ICE-NUCLEATING ACTIVE AGENTS IN LARVAE OF THE RICE STEM BORER, CHILO SUPPRESSALIS WALKER (LEPIDOPTERA, PYRALIDAE)

摘要

Chemical properties of the ice-nucleating active agents (INAs) distributed in the muscle of diapausing larvae of the rice stem borer, Chile suppressalis Walker were studied. Sensitivity to protease indicated that the INAs were proteinaceous. The INAs were stable at at least 50 degrees C for 5 min, and active over a broad pH range (pH 2.0 to 8.0) and after delipidation treatments. These results suggest that the chemical characteristics of the INAs of the muscle in the diapausing larvae are similar to those of the exogenous agents in the nondiapausing ones in Fusarium sp. After differential centrifugation of muscle homogenate of the diapausing larvae, the crystallization temperature of the 105,000g pellet was the highest of all fractions separated, implying that INAs are present in microsome membrane.