The morphology of bacteriophage ST1 was examined by transmission electron microscopy. Bacteriophage particles were fixed by mixing 25 ìl of the bacteriophage suspension with 25 ìl of 50% glutaraldehyde in 4% paraformaldeyde. A 5-ìl aliquot of this mixture was placed on a carbon Formvar-coated copper grid (Proscitech, Brisbane, Queenland, Australia) and allowed to adsorb for 5 min at room temperature. The bacteriophage was negatively stained with 2% (w/v) phosphotungstic acid for 1 min then inspected with a JEM-1230 transmission electron microscope (JEOL, Tokyo, Japan) at different magnitudes. The bacteriophage size was determined from the average of five independent measurements.