BIOCHEMICAL AND PHYSICAL ORGANIZATION OF BACTERIAL ICE NUCLEI

THE BIOCHEMICAL AND PHYSICAL ORGANIZATION OF BACTERIAL ICE NUCLEI ARE EXAMINED. AN UNDERSTANDING OF THE STRUCTURE OF THESE NUCLEI IS KEY TO THEIR PRESERVATION AND BIOTECHNOLOGICAL EXPLOITATION. FORMATION OF MEMBRANE-BOUND AGGREGATES OF ICE NUCLEATION PROTEINS HAS BEEN POSTULATED TO BE THE BASIS OF THE ACTIVITY OF THESE NUCLEI AT TEMPERATURES NEAR THE FREEZING POINT OF WATER. THE PROGRAM GOALS ARE: (A) FRACTIONATION OF NUCLEATING MEMBRANES BY PHYSICAL METHODS; AND (B) VISUALIZATION OF NUCLEI ON MEMBRANES BY IMMUNOFLUORESCENCE AND IMMUNOELECTRON MICROSCOPY. THE PROPOSED RESEARCH UTILIZES CLONING AND EXPRESSION OF BACTERIAL ICE NUCLEATION GENES IN E. COLI, CHEMICAL CROSS-LINKING OF PROTEINS, IMMUNOFLUORESCENCE AND IMMUNOELECTRON MICROSCOPY, AND ESTABLISHED BIOCHEMICAL, PHYSICAL, AND IMMUNOLOGICAL TECHNIQUES. THE PLANNED INVESTIGATIONS WILL DEMONSTRATE THE IMPORTANCE OF AGGREGATES OF ICE NUCLEATION PROTEINS IN NUCLEI ACTIVE AT TEMPERATURES CLOSE TO FREEZING. THIS RESEARCH WILL DETERMINE FUTURE DIRECTIONS FOR INVESTIGATION AND DEVELOPMENT OF CELL-FREE ICE NUCLEI.