Exercise 9: endospore staining

Question 1

Endospore def:

Answer 1

a dormant (metabolically inactive) survival structure made by only a few genera of microorganisms in response to unfavorable environmental conditions

Question 2

What are two common and clinically important genera that usually create endospores?

Answer 2

• Bacillus ssp.

- Clostridium ssp.

Question 3

What are some environmentally harsh conditions that could cause endospores to be produced?

Answer 3

• extreme heat, extreme cold, depletion of nutrients, lock of water, high levels of wast products or high levels of radiation

Question 4

Sporogeneis (sporulation) def:

Answer 4

creation of an endospore

Question 5

What is the spore surrounded by? and what makes up this?

Answer 5

• a spore coat

- multiple keratinized layers

Question 6

What does the spore coat protect the spore from?

Answer 6

the effects of boiling, freezing, certain types of radiation and desiccation

Question 7

Germination:

Answer 7

conversion of an endospore to a vegitative cell

Question 8

What are some positions the endospore can be in?

Answer 8

• central, subterminal, or terminal

Question 9

What age of cultures are more likely to produce endospores? & why?

Answer 9

• 48-72 hour cultures

- because young cultures (18-30 hour) are not yet nutritionally stressed

Question 10

How long do you steam the smear for?

Answer 10

3-5 minutes

Question 11

Why do you steam it?

Answer 11

it’s thought to increase the porosity of the keratinized layer comprising the spore cote. allows the malachite green to penetrate the spore coat

Question 12

What does water do?

Answer 12

it serves to decolorize the vegetative cells