Sporulation Flashcards

1
Q

Sporulation

A
  • 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
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2
Q

Endospores and Infectious Disease

A
  • harmless until they germinate
  • anthrax
  • tetanus
  • botulism
  • gas gangrene
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3
Q

Endospores as a sterility indicator for autoclaves

A
  • 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
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4
Q

Structure of an Endospore-Core

A

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

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5
Q

Structure of an Endospore-Cortex

A

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

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6
Q

Structure of an Endospore-Coat

A
  • protein layers that are impermeable to most chemicals

- the coat is responsible for the spores resistance to chemicals

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7
Q

Stages in Sporulation

A
  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
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8
Q

Factors involved in spore septum formation and chromosome partitioning-FtsZ

A
  • Filamentation Temperature Sensitive
  • forms a FtsZ ring at both cell poles
  • FtsZ ring is formed and septum formation follows
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9
Q

Factors involved in spore septum formation and chromosome partitioning-Spo0A

A
  • 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
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10
Q

Factors involved in spore septum formation and chromosome partitioning-SpoIIIE

A

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

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