Lab 7 - Endospore bacteria

Question 1

How do endospores withstand heat and adverse conditions?

Answer 1

• Outer spore coat of dense proteins
• Inner membrane extremely impermeable
• Spore core with low water content and high acid complexes to preserve structure

Question 2

Which bacteria produce endospores?

Answer 2

Gram positive = Bacillus, Clostridium, Clostridioides

Question 3

What feature of endospores is used to isolate them from vegetative cells?

Answer 3

Withstand pasteurisation (80C for 15-20mins) which is lethal for vegetative cells

Question 4

Briefly describe the method used in this experiment

Answer 4

1. Add soil and water to McCartney bottle and shake
2. Incubate 45mins in 80C waterbath
3. Make dilutions of the soil-water in distilled water
4. Pipette dilutions onto PYEA and BA plates\
5. Incubate 2-4 days at room temperature
6. Select and stain colonies

Question 5

What are the expected colonies and spores from this experiment?

Answer 5

Colonies = smooth round colonies and fuzzy filamentous colonies
Spores = green, free or inside cells (central and subterminal)