127 - Bacterial Genetics

Transposition
Segment of DNA (eg, transposon) that can “jump” (excision and reintegration) from one location to another, can transfer genes from what to what and vice versa?

Transposition
When excision occurs, it may include some what, which can be incorporated into a plasmid and transferred to another bacterium?

Recall the image for Transposition

What are examples of spore-forming bacteria?

Some bacteria can form spores - when?

Some bacteria can form spores at the end of the stationary phase when what are limited?

Spores are highly resistant to what?

What do spores have in their core?

What is the metabolic activity of spores?

What must be done to potentially kill spores?

Exotoxins or Endotoxin?

Source: Certain species of gram ⊕ and gram ⊝ bacteria

Exotoxins or Endotoxin?

Source: Outer cell membrane of most gram ⊝ bacteria

Exotoxins or Endotoxin?

Secreted from Cell

Exotoxins or Endotoxin?

Not secreted from cell

Exotoxins or Endotoxin?

Chemistry: Polypeptide

Exotoxins or Endotoxin?

Chemistry: Lipid A component of LPS (structural part of bacteria; released when lysed)

Exotoxins or Endotoxin?

Location of genes: Plasmid or bacteriophage

Exotoxins or Endotoxin?

Location of genes: Bacterial chromosome

Exotoxins or Endotoxin?

Adverse effects: High (fatal dose on the order of 1 μg)

Exotoxins or Endotoxin?

Adverse effects: Low (fatal dose on the order of hundreds of micrograms)

Exotoxins or Endotoxin?

Clinical effects: Fever, shock (hypotension), DIC

Exotoxins or Endotoxin?

Mode of action: Induces TNF, IL-1, and IL-6

Exotoxins or Endotoxin?

Antigenicty: Induces high-titer antibodies called antitoxins

Exotoxins or Endotoxin?

Antigenicty: Poorly antigenic

Exotoxins or Endotoxin?

Vaccines: Toxoids used as vaccines

Exotoxins or Endotoxin?

Vaccines: No toxoids formed and no vaccine available

Exotoxins or Endotoxin?

Heat stability: Destroyed rapidly at 60°C (except staphylococcal enterotoxin and E coli heatstable toxin)

Exotoxins or Endotoxin?

Heat stability: Stable at 100°C for 1 hr

Exotoxins or Endotoxin?

Typical diseases: Tetanus, botulism, diphtheria

Exotoxins or Endotoxin?

Typical diseases: Meningococcemia; sepsis by gram ⊝ rods

What is the source of Exotoxins?

What is the source of Endotoxins?

What is the chemistry of Exotoxins?

What is the chemistry of Endotoxin?

What is the location of genes for Exotoxins?

What is the location of genes for Endotoxins?

What are the clinical effects of Endotoxin?

What is the mode of action for Endotoxins?

What is the antigenicity of Exotoxins?

What is the antigenicity of Endotoxins?

What are the vaccines for Exotoxins?

What are the vaccines for Endotoxins?

What is the heat stability of Exotoxins?

What is the heat stability of Endotoxins?