One dye used to stain cells all the same color.
-can be used to tell morphology (shape) and size (although negative staining is better for size).
-cationic dyes are positively charged and are attracted by ionic forces to the negatively charged surface of bacterial cell.
-common dyes: methylene blue, crystal violet
anaerobic green: endospore/ free spores of clostridium
aerobic green: endospore/free spores of bacillus
anaerobic pink: vegetative/sporangia of clostridium
aerobic pink: vegetative/sporangia of bacillus
media whose exact chemical composition is known and in many instances is designed for isolation, selection, of differentiation
differentiaes or distinguishes b/w diff. types of organisms based on diff. in appearance of growth or color changes.
ex. EMB, blood agar,
B. Clear zone around and under bacterial growth = starch hydrolyzed by the organism’s amylase to glucose