basic, positively charged chromophore

Methylene Blue

Crystal Violet

no charge

Sudan Black stains granules of Poly-B-OH-butyric acid

water insoluble

India Ink (colloid suspension of carbon particles)

Stains background in brightfield micr.

Nigrosin (repelled by - cell surface)

India Ink (no penetration)

Tells morphology and size

One cationic dye used and absorbed by negative cell

Methylene blue and Crystal Violet

staining procedure which causes cells to stain differently based on properties of the cell

Gram stain

Acid-fast stain

Gram +: high peptidoglycan, low lipid

Gram -: low peptidoglycan, high lipid

Crystal Violet>Iodine>Ethanol>Saffranin

Acid fast has high wax content and will appear red

Non-acid fast will appear blue

Calbol fuschin>steam>acid alcohol>methylene blue

Mycobacterium: tuberculosis, leprae; gram + tapered rods

Nocardia

spores are stained while microorganisms and vegetative cells are decolorized

Endospores=green+pink

Free spores=green

Malachite green>steam>water>saffranin

Bacillus= aerobic, gram + rod

Clostridium= anaerobic, gram + rod

Sporsarcinae= cocci

Anaerobic green= spore Clostridium

Aerobic green= spore Bacillus

Anaerobic pink= vegetative Clostridium

Aerobic pink= spore Bacillus