Microbiology Chapter 9

Front 1

Exotoxins and type III cytotoxins act on

Back 1

Intracellular targets

Front 2

These types of toxins generally act on the cell surface

Back 2

Endotoxin
membrane damaging toxin
superantigen

Front 3

These toxins modulate targets in the extracellular matrix

Back 3

Exoenzymes

Front 4

Mechanism of Diphtheria toxin

Back 4

ADP ribosylation of elongation factor 2 (EF-2) which irreversibly blocks protein synthesis

Front 5

Mechanism of Cholera toxin

Back 5

ADP ribosylation of G protein leading to increased intracellular cAMP (intestinal epithelium). This provokes movement of massive quantities of fluid across intestinal membrane into the lumen.

Front 6

These genus-es produce spores

Back 6

Clostridium, Bacillus

Front 7

Mechanism of Botulinum toxin

Back 7

Inactivation of vesicle fusion at peripheral nerve ending inhibits STIMULATORY neurotransmitter release resulting in FLACID paralysis.

Front 8

Mechanism of Tetanus toxin

Back 8

Inactivation of vesicle fusion at interneuronal junction inhibits the release of INHIBITORY neurotransmitters resulting in SPASTIC paralysis

Front 9

Roles of A and B domains in exotoxins

Back 9

The B domain binds to the cell membrane and delivers the enzymatically active A domain into the host cell

Front 10

Endotoxins will come from bacteria with which Gram stain what color?

Back 10

Pink

Front 11

The pattern recognition receptor from Gram negative bacteria is

Back 11

Endotoxin

Front 12

The pattern recognition receptor from Gram positive bacteria is

Back 12

Lipoteichoic acid

Front 13

Pattern recognition receptors bind to _____ in order to propagate the intracellular signal

Back 13

Toll like receptors (TLR) on cell surface

Front 14

Small amount of bacterial endotoxin targeting Kupfer cells leads to

Back 14

Increase in IL-1, TNF which leads to fever

Front 15

Small amounts of bacterial endotoxin targeting Neutrophils leads to

Back 15

Increase in kinins leading to vasodilation

Front 16

Small amounts of bacterial endotoxin targeting B lymphocytes leads to

Back 16

Activation of B lymphocyte and increased Ab synthesis

Front 17

Small amounts of bacterial endotoxin binding complement leads to

Back 17

Activation of alternative pathway leading to inflammation

Front 18

Large amounts of bacterial endotoxin can cause

Back 18

Shock (hypotension)and DIC

Front 19

Endotoxins induce the release of ___ from mononuclear phagocytes which induces B (but not T lymphocytes) to divide

Back 19

IL-1

Front 20

Sepsis from meningococcal infection can lead to adrenal insufficiency and rapid death in _______ syndrome

Back 20

Waterhouse-Friderichson

Front 21

Three ways endotoxin leads to coaguable state

Back 21

1. Activation of Hageman (XII) factor
2. Platelet degranulation
3. PMNs release proteins that stabilize fibrin

Front 22

Lecithinase (produced by gas gangrene) lyses cells by targeting

Back 22

Phosphatidylcholine in cell membrane

Front 23

The alpha toxin of staph aureus induces hemolysis (and leukolysis) by

Back 23

Forming pores in the cell membrane

Front 24

This toxin from some streptococci will form pores that lead to lysis of RBCs but not neutrophils or macrophages.

Back 24

Streptolysin O
this does however lead to WBC death by opening lysosomes and inducing apoptosis

Front 25

These toxins bind the MHC of an APC with the T cell receptor on lymphocytes to stimulate wasteful and inefficient antibody production

Back 25

Superantigens

Front 26

These toxins include hyaluronidase (secreted by some Gram positives) which breaks down the ground substance of connective tissue

Back 26

Exoenzymes

Front 27

Streptococcus pyogenes produces _____ which activates plasminogen, converting it to plasmin that breaks up fibrin clots

Back 27

Streptokinase

Front 28

Chemically inactivated toxin used as vaccine

Back 28

Toxoid

Front 29

This potential problem of antitoxin administration is an immune reaction against foreign antigens.

Back 29

serum sickness