MOLECULAR CYTOSKELETAL MICROSCOPY PROBES AND BIOLOGICAL WIRES

NOVEL PROBES ARE INTRODUCED FOR THE STUDY OF CYTOSKELETAL STRUCTURES AND PROCESSES BY ELECTRON MICROSCOPY. THESE COMPRISE LARGE CLUSTER COMPLEXES OF GOLD, PLANTINUM, AND PALLADIUM 0.8 NM-2.4 NM IN DIAMETER COVALENTLY LINKED TO PHALLOIDIN, CYTOCHALASIN B, COLCHICINE, AND TAXOL VIA A SINGLE REACTIVE FUNCTIONAL GROUP INCORPORATED INTO THEIR LIGAND SPHERES. THE CONJUGATES CAN PENETRATE 20-30 MUM OR MORE INTO CELL SECTIONS AND ACHIEVE SIGNIFICANTLY HIGHER RESOLUTION THAN COLLOIDAL GOLD-ANTIBODY CONJUGATES. THEY ARE MICROINJECTABLE; COMPATIBLE WITH LIVING CELLS; AND USED TO EXTEND THE USE OF ELECTRON MICROSCOPY TO THE STUDY OF ORGANISMS SUCH AS PROCARYOTIC BACTERIA, IN WHICH ANTIBODY PROBES ARE NOT FEASIBLE. COMBINED LABELS INCLUDING BOTH A GOLD CLUSTER AND A FLUORESCENT MOIETY ARE BEING USED TO PREPARE ADDITIONAL PROBES WITH THE SAME MOLECULES, ENABLING CORRELATION OF FLUORESCENCE CONFOCAL MICROSCOPY AND ELECTRON MICROSCOPY DATA FROM A SINGLE LABELING EXPERIMENT. THE PREPARATION OF MOLECULAR WIRES IS BEING ATTEMPTED BY THE IN VITRO ASSEMBLY OF GOLD-LABELED CYTOSKELETAL COMPONENTS, FOLLOWED BY SILVER ENHANCEMENT.