Microbial Toxins

Question 1

Infectious diseases cause about ________ of deaths worldwide.

Answer 1

1/3

Question 2

________ is the most toxic microbial toxin known.

Answer 2

Botulinum

Question 3

Polysaccharides make lipid A _________.

Answer 3

soluble

Question 4

Endotoxin can cause ___________.

Answer 4

(1) inflammation, by activating the complement cascade; (2) fibrinolysis, by activating Hagemen factor; (3) hypotension, by activating bradykinin (also through Hagemen); and (4) DIC, by activating TNF-alpha -> factor VII -> factor X

Question 5

Hemolysins are often __________.

Answer 5

pore-forming toxins

Question 6

Gram-positive bacteria tend to make ___________ more than Gram-negative bacteria.

Answer 6

pore-forming cytolysins

Question 7

Superantigens can cause _____________.

Answer 7

toxic-shock syndrome and necrotizing fasciitis

Question 8

Staphylococcus aureus and streptococcus pyogenes together produce __________.

Answer 8

more than 19 different superantigens

Question 9

Diphtheria infection leads to ___________.

Answer 9

bull neck, conjunctivitis, myocarditis, and colonization of the pharyngeal membrane

Question 10

How does diphtheria toxin kill cells?

Answer 10

It modifies EF-2 (elongation factor-2) and thereby inhibits protein synthesis.

Question 11

Diphtheria is only taken up by ___________.

Answer 11

susceptible cells–those with the membrane receptor for diphtheria toxin (epidermal growth factor receptor, EGFR)

Question 12

Diphtheria binds with its ___ subunit and kills with its ______ subunit.

Answer 12

B; A

Question 13

________ treat diphtheria.

Answer 13

Anti-toxin and erythromycin

Question 14

Diphtheria toxin and Pseudomonas aeruginosa exotoxin A both _________.

Answer 14

inhibit protein synthesis by transferring the ADP-ribose portion of NAD to EF-2

Question 15

Although they do the same thing inside cells, diphtheria toxin and P. aeruginosa toxins _________.

Answer 15

are not cross-reactive; they have different antigenic regions and affect different cells based on membrane-receptor affinity

Question 16

____________ all also inhibit protein synthesis, similar to diphtheria and P. aeruginosa toxin, but they do so by ________.

Answer 16

Shiga toxin, enterohemorrhagic E. coli toxin, and ricin; modifying the 60S subunit of eukaryotic ribosome

Question 17

Type III secretion is ____________.

Answer 17

injection directly into host cells through needles; common in Gram-negative bacteria

Question 18

Type VI secretion is _______________.

Answer 18

needle insertion into other bacteria

Question 19

Botulinum toxin works on __________, while tetanus toxin works on _________.

Answer 19

motor neurons; spinal interneurons

Question 20

Botulinum toxin is released by __________.

Answer 20

cell lysis

Question 21

Some exotoxins that degrade the extracellular matrix are _________.

Answer 21

hyaluronidase, collagenase, elastase, and streptokinase

Question 22

Although they both inhibit cell protein synthesis, diphtheria toxin and pseudomonas aeruginosa exotoxin act on ________.

Answer 22

different cells; PAE targets liver cells, and DT attacks heart, liver, and kidney cells

Question 23

The exotoxins that affect intracellular signaling pathways are __________.

Answer 23

Vibrio cholerae, E. coli, anthrax, C. diff, and B. pertussis

Question 24

Tetanus toxin inhibits ___________.

Answer 24

VAMP (and the subsequent release of vesicles)

Question 25

Staphylococcal enterotoxins and streptococcal exotoxins are both _________.

Answer 25

superantigens

Question 26

Diphtheria does not leave the __________.

Answer 26

respiratory tract or skin–only its toxin does