ABSTRACT
Materials and methods used for the preparation of bacterial and fungal pathogens for bright-field microscopic observation, for differential staining of pathogens in host cells and whole mounts, and plastic prints of host surfaces are described. Wittmann's Direct Mounting Medium is used for direct mounting, fixing and staining of fungal preparations. Aniline or trypan blue is used to stain nuclei of Rhizoctonia solani and related fungi. Techniques have been developed for semi-quantitative and quantitative assessment of Gram-positivity of bacteria. Bacteria stained blue are Gram-positive and those stained red are Gram-negative. Growing a fungus as a slide culture results in preparation in which the sporulation characteristics remain undisturbed and spores remain attached to the sporophores thus facilitating their identification. Magdala Red-Licht Grun stains mycelium, fungal spores and bacterial cells brilliant red and host tissues green. Bacterial cells are violet-purple; cellulose walls, green to yellow; lignified tissues, blue; host nuclei, pale blue; and fungal nuclei, deep purple.
