Schaeffer & Fulton 1933
Endospores are non-reproductive structures produced by some Gram-positive bacteria, being a form of resistance
in unfavorable conditions, unlike the eukaryotic spores wich have a reproductive role. Bacterial endospores exists
in a dormant state waiting for reactivation when conditions become favorable.
Staining technique consists in dyeing the smear with malachite green. Only the endospore
retain the stain. Vegetative cell is decolorized when washed with water. The counterstain
safranin is then used to color vegetative cell.
Malachite green solution 5%,
Safranin solution 0.5% or diluted fuchsin.
Dry and heat-fix the slide then cover it with Malachite green solution. Heat the slide for 3
minutes; avoid boiling. Wash in running tap water.
Cover the slide with Safranin solution and wait 1 minute. Remove solution, wash and dry
|Malachite green stained,
spores (Bacillus anthracis)
Light-green inclusions (endospores) in pink-to-red vegetative cells.
A demonstration of staining procedure is available in video section.
(c) Costin Stoica