Enzymes and toxins

Question 1

Extracellular enzymes and what they do

Answer 1

Hyaluridonase-breaks down hyaluronic acid that helps keep tissue together to allow pathogen in host tissues; coagulase-fibrin formation on cells and protects bacteria from host; streptokinase-fibrinolytic enzyme dissolves clots to allow spread of bacteria

Question 2

Exotoxin

Answer 2

cell membrane: make them permeable; protein synthesis: ribosomes are the target; second messenger pathway disruption: stimulate cAMP or cGMP to lead to hypersecretion of fluids; superantigens: T cell proliferation leads to cytokine release which causes fever/shock/vomit; proteases: break down proteins

Question 3

A-B toxins

Answer 3

A is the active component and B binds to the cell to allow transfer

Question 4

Examples of A-B toxins

Answer 4

Shiga toxin from EH E. Coli (O157:H7), ADP-ribosyltransferase: transfers ADP-ribose from NAD to target protein

Question 5

Enterotoxins

Answer 5

affect enterocytes, produced by E. Coli, Salmonella enterica

Question 6

Neurotoxins

Answer 6

tetanus and botulinum inhibit neurotransmitters for muscles

Question 7

Endotoxins

Answer 7

also known as LPS, released when a bacteria dies or is infected, Lipid A has biological activity, low concentrations lead to alarm reactions and high concentrations lead to shock and death
MAIN signs: fever, disseminated intravascular coagulation, shock