Sporulation

Question 1

Sporulation

Answer 1

• when Bacillus or Clostridium are faced with limiting supplies of C/N, the cells sporulate
• endospores are resistant to heat, UV radiation, desiccation and toxic chemicals
• spores can remain dormant for hundreds of years but will germinate into growing cells when nutrients become available

Question 2

Endospores and Infectious Disease

Answer 2

• harmless until they germinate
• anthrax
• tetanus
• botulism
• gas gangrene

Question 3

Endospores as a sterility indicator for autoclaves

Answer 3

• glass ampule w/ media
• after autoclaving flexible vial is squeezed to break and release medium onto spore strip
• yellow medium means spores are viable, autoclaved objects not sterile
• red means spores were killed, autoclaved objects are sterile

Question 4

Structure of an Endospore-Core

Answer 4

-dehydrated cytoplasm, containing DNA, ribosomes, enzymes and high level of calcium dipicolinate (thought to confer heat resistance properties of the spore)

Question 5

Structure of an Endospore-Cortex

Answer 5

a modified cell wall/peptidoglycan layer that is not as highly cross linked as in vegetative cell

Question 6

Structure of an Endospore-Coat

Answer 6

• protein layers that are impermeable to most chemicals

- the coat is responsible for the spores resistance to chemicals

Question 7

Stages in Sporulation

Answer 7

1. Chromosome condenses into axial filament, septum begins to form
2. septum is complete and cells divided into 2 compartments-mother cell and forespore
   - a copy of the chromosome is translocated into the forespore compartment
3. mother cell septum grows around the forespore (engulfment)
   - the forespore has 2 sets of inner and outer membranes
4. space between the membranes of the forespore is filled with cortex made of newly synthesized peptidoglycan on the surface of the inner membrane
5. A spore coat is laid down around the outer membrane
   - the coat is made of proteins synthesized by the mother cell
6. spore develops resistance properties
7. release of mature spore as a result of mother cell lysis

Question 8

Factors involved in spore septum formation and chromosome partitioning-FtsZ

Answer 8

• Filamentation Temperature Sensitive
• forms a FtsZ ring at both cell poles
• FtsZ ring is formed and septum formation follows

Question 9

Factors involved in spore septum formation and chromosome partitioning-Spo0A

Answer 9

• the master regulator of sporulation genes
• spo0A- mutant remains at stage 0 of sporulation
• a TF that regulates over 120 genes including those required for chromosomal axial filament and FtsZ ring formation

Question 10

Factors involved in spore septum formation and chromosome partitioning-SpoIIIE

Answer 10

A DNA translocase that translocates chromosome into the forespore compartment by a mechanism similar to plasmid transfer during conjugation