L3: Sporulating Bacteria Flashcards
What is the production of endospores called?
Sporulation.
Are endospores produced by all bacteria?
Only some gram positive bacteria.
Spores are very resistant ……. (3)
Heat, chemicals, radiation.
Spores are very resistant to heat, chemicals, and radiation, why is this useful?
Enables survival during difficult times.
Define endospores?
Highly differentiated cells that are extremely resistant to heat, harsh chemicals, and radiation
What part of the life cycle are endospores considered to be?
The dormant stage.
Vegetative cell –> endospore –> Vegetative cell.
What are the 3 steps in sporulation?
Activation
Germination
Outgrowth
Describe what happens at the Activation step.
Occurs when endospores are heated for several minutes.
Nutrients are added.
Describe what happens at the Germination step. (4)
Very rapid, takes a few mins.
Loss of microscope refractility.
Loss of heat and chemical resistance.
Increased ability to be stained by dyes.
Describe what happens at the Outgrowth step.
Visible swelling, due to uptake of water, synthesis of RNA, DNA and proteins.
Cell emerges from broken endospore.
–> continues to grow.
Under a light microscope, why might endospores be seen as un stained regions?
They are impermeable to many dyes.
Name two structural facts about endospores.
Refractile
Hard to stain.
What makes an endospore more ‘structurally complex’ than the vegetative cell?
It has many layers.
1) Exosporium (outer)
2) Spore coats - composed of layers of spore specific proteins
3) Cortex - loosely cross linked peptidoglycan
4) Core
How does having high levels of calcium dipicolinate help an endospore?
Helps reduce water content of the core.
How much water content does the core of an endospore have compared to vegetative cells, and what does this result in?
10-25% compared to vegetative cells,
Results in a gel like cytoplasm. Mast.
What is the pH of the core like in endospores?
Lower than normal cells
What are SASPs?
Small Acid Soluble Proteins
SASPs are made during the sporulation process; what is their function?
Bind tightly to DNA in core and protect it from damage from uv radiation, dessication and dry heat.
Change DNA structure from B to a more compact A form.
–> makes it more resistant to uv radiation.
What type of ions do endospores contain a lot of?
Calcium ions.
Ca2+
What are the two main genus names for spore forming bacteria?
Clostridium …
Bacillus …
Clostridium perfringens is part of the normal flora of the gut, what can it cause and why?
It can cause food poisoning, as it can survive heat/cooking.
What disease is Clostridium tetani associated with?
Tetanus
What type of organism is Clostridium tetani?
Soil organism.
What are the 2 spore forming bacteria that can cause food poisoning?
Clostridium perfringens
Clostridium botulinum
