Methods for scanning and transmission electron microscopy of normal and damaged gram-negative bacteria

Preparatory procedures and different types of electron microscopical imaging of bacterial specimens are described. Transmission electron microscopy (TEM) was performed on ultra-thin sections of plastic embedded material and negatively stained specimens. Metal coated, whole bacteria were prepared for scanning electron microscopy (SEM). The rapid procedure for TEM observation of negatively stained specimens indicates size, shape and appendages. TEM micrographs of ultra-thin sections show details of the cell wall and internal structures of the cytoplasm. SEM is superior in demonstrating size and gross surface morphology. The three methods are complementary in the study of bacterial cell ultrastructural morphology.