Spore stain

What is the difference between the vegetative cell and endospore?

• Vegetative cell: The metabolically active, growing form of the bacterium.

• Endospore (spore): A dormant, tough structure produced when environmental conditions become unfavorable to protect the bacterial DNA. When conditions improve, it can return to the vegetative state.

What is the primary stain, counterstain, and is there a decolorizer?

• Primary: malachite green

• Counterstain: safranin

• Decolorizer: none

What is the charge of the stains used in this lab?

• Primary and counterstain are positive

What is unique about the procedure for the spore stain?

• There’s no decolorizer and it requires heat

What will happen if there is not enough steam/heat?

• Endospore positive will appear red (endospore negative)

What will happen if you forget to apply malachite green?

• Endospore positive will appear red (endospore negative)

What will happen if you accidentally applied a decolorizer?

• Endospore positive will appear red (endospore negative)

What will happen if you forget to apply safranin?

• Endospore negative will not stain and appear colorless

What color is the endospore/spore? The vegetative cell?

Endospore Positive: Green (free spores/endospores)

Pink vegetative cells

Endospore negative: ALL pink

Bacteria Species (A):

Endospore +/ - :

Name B,C,D:

Bacillus cereus

Endospore positive

B: Pink vegetative cell

C: Green endospore inside pink vegetative cell

D: Free green spore

Bacteria Species:

Endospore +/ - :

Escherichia coli

Endospore negative

Bacteria Species:

Endospore +/ - :

Klebsiella pneumoniae

Endospore negative

Bacteria Species:

Endospore +/ - :

Staphylococcus aureus

Endospore negative

Bacteria Species:

Endospore +/ - :

Streptococcus agalactiae

Endospore negative