Bacterial Endospores Flashcards
Bacterial Endospores (Spores)
-Enable bacteria to withstand hostile conditions
-Facilitates survival of bacteria
-Most common genera of bacteria that produce endospores
>Bacillus
>Clostridum
-16 genera of Gram Positive spore formers
-1 genus of Gram Negative spore former
Most common genera of bacteria that produce endospores
- Bacillus
2. Clostridium
Endospores contain
- Copy of the organisms chromosome
- Small amount of cytoplasm
- Small amount of cell machinery
Spore Coat Contains
- Keratin
- Protein
- Calcium
- Dipicolinic Acid
- Peptidoglycan
Sporulation
The formation of endospores
- A vegetative bacterial cell will form spores when exposed to adverse environmental conditions such as
1. Nutrient Limitation
2. Waste Accumulation
3. Temperature Changes
A vegetative bacterial cell will form spores when exposed to adverse environmental conditions such as?
- Nutrient Limitation
- Waste Accumulation
- Temperature Changes
How Long Do Endospores Survive?
- 25 million years or longer
- Borucki, R.J. (1995, May 19), revival and identification of bacterial spores in 25 to 40 million year old Dominican amber
How resistant are Endospores?
Endospores survive extremes:
- Heat
- Drying
- Freezing
- Radiation
- Chemicals
- Pressure
Germination
The Breaking of Dormancy
(endospores revert back to active vegetative cells)
-When favorable conditions arise, a fully active vegetative cell emerges
-Water must be available
-Amino Acid or organic salt must also be present
-These stimulate the formation of digestive enzymes which breakdown the cortex and expose the core to water
-Germination can occur as rapidly as 2 hours
Endospore forming Genera and Diseases
- Bacillus Anthrax
- Cutaneous Anthrax- mortality rate 20%
- Pulmonary Anthrax- Rapid death; mortality rate 99%
- Gastrointestinal Anthrax- very rare; high mortality rate - Bacillus cereus
- Gastrointersinal- Food poisoning
Endospore Forming Genera and Diseases: Bacillus Anthrax
- Cutaneous Anthrax- mortality rate 20%
- Pulmonary Anthrax- Rapid death; mortality rate 99%
- Gastrointestinal Anthrax- very rare; high mortality rate
ENdospore Forming Genera and Diseases: Bacillus cereus
-Gastrointersinal- Food poisoning
Diseases caused by Spore Formers
- Clostridium tetani- tetanus, lockjaw (tetanospasmin is a neurotoxin)
- Clostridium perfringens- gas gangrene (anaerobic cellulitis)
- Clostridium botulinum- botulism
- Clostridium difficile- antibiotic associated colitis
Schaeffer- Fulton Spore Stain
This technique uses heat to force the stain through resistant spore coat
- Primary Dye: Malachite Green (6 minutes on a hot plate)
- Water rinse (water is the decolorizer)
- Counterstain: Safranin (2 minutes)
