6.E: Virulence Factors that Damage the Host (Exercises)
- Page ID
- 8025
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)These are homework exercises to accompany Kaiser's "Microbiology" TextMap. Microbiology is the study of microorganisms, which are defined as any microscopic organism that comprises either a single cell (unicellular), cell clusters or no cell at all (acellular). This includes eukaryotes, such as fungi and protists, and prokaryotes. Viruses and prions, though not strictly classed as living organisms, are also studied.
Study the material in this section and then write out the answers to these questions. Do not just click on the answers and write them out. This will not test your understanding of this tutorial.
- List 3 general categories of virulence factors that damage the host.
2. Matching:
_____ Intercellular regulatory proteins produced by one cell that subsequently bind to other cells in the area and influence their activity in some manner. Regulate body defense mechanisms.
_____ Defense regulatory chemicals that promote an inflammatory response by enabling white blood cells to leave the blood vessels and enter the surrounding tissue, by chemotactically attracting these white blood cells to the infection site, and by triggering neutrophils to release killing agents for extracellular killing.
_____ A condition where bacteria enter the bloodstream causing harm.
_____ A decreased volume of circulating blood.
_____ Reduced delivery of nutrients and oxygen via the blood. This can lead to ischemia, a restriction in blood supply that results in damage or dysfunction of tissue.
_____ Respiratory failure from acute inflammation in the lungs, injury to capillaries in the alveoli of the lungs, and pulmonary edema.
_____ The formation of clots within the blood vessels throughout the body.
A. inflammation
B. septicemia
C. chemokines
D. cytokines
E. DIC
F. ARDS
G. septic shock
H. hypovolemia
I. hypotension
J. hypoperfusion
3. Define hypotension and describe the biological mechanism behind 3 factors that contribute to hypotension.
4. Define hypovolemia and describe the biological mechanism behind 3 factors that contribute to hypovolemia.
5. Define hypoperfusion and describe the biological mechanism behind 3 factors that contribute to hypoperfusion.
6. Describe the biological mechanism behind ARDS and how ARDS contributes to hypoperfusion.
7. Define pyroptosis and state its role in inducing inflammation.
8. List three types of exotoxins.
A.
B.
C.
9. Define exotoxin.
10. The body's major defense against exotoxins is _______________________________________________.
11. Define superantigen .
12. Briefly describe the mechanism by which superantigens cause harm to the body.
13. Name 2 superantigens and give an example of a bacterium that produces each.
A.
B.
14. Match the following descriptions with the exotoxin:
_____ Causes lysis of white blood cells and other immune cells by damaging their cell membrane . It is produced by various pyogenic bacteria including Staphylococcus aureus and Streptococcus pyogenes.
______ Causes the respiratory damage and violent coughing episodes seen during whooping cough.
______ Damages the membranes of intestinal mucosal cells causing hypersecretion of fluids; triggers the production of inflammatory cytokines; attracts and destroys neutrophils causing them to release their lysosomal enzymes for further tissue damage leading to hemorrhagic necrosis.
a. leukotoxins
b. Toxin A
c. Toxin B
d. Bordetella tracheal cytotoxin
15. Usually deep puncture-type wounds are needed for the development of gas gangrene. The resulting infected tissue shows massive edema, is mushy to the touch, and the infection spreads very rapidly through the tissue. In terms of the causative organism and its products, discuss why.
1. State the functions of the A component and the B component in A-B toxins. .
2. Match the following descriptions with the exotoxin:
_____ Produced by certain strains of Escherichia coli such as E. coli O157:H7. These toxins kill intestinal epithelial cells of the colon and cause bloody diarrhea. Less commonly, the toxins enter the blood and are carried to the kidneys where they damage endothelial cells of the blood vessels and cause hemolytic uremic syndrome (HUS).
_____ Produced by a species of Clostridium. This is a neurotoxin that acts peripherally on the autonomic nervous system. This toxin binds to and enters the presynaptic neuron and blocks its release of acetylcholine. This causes a flaccid paralysis, a weakening of the involved muscles.
_____ Produced by a species of Clostridium. This is a neurotoxin that binds to inhibitory interneurons of the spinal cord and blocks their release of inhibitor molecules.The toxin, by blocking the release of inhibitors, keeps the involved muscles in a state of contraction and leads to spastic paralysis, a condition where opposing flexor and extensor muscles simultaneously contract.
_____ At low levels, this toxin inhibits the release of proinflammatory cytokines such as interleukin-1 (IL-1), tumor necrosis factor-alpha, (TNF-alpha), and NO. This may initially reduce immune responses against the organism and its toxins. But at high levels, it is cytolytic for macrophages, causing release of high levels of interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-alpha), and NO. Excessive release of these cytokines can lead to a massive inflammatory response and the shock cascade, similar to septic shock.
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a. diphtheria exotoxin |
f. anthrax lethal toxin |
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b. cholera exotoxin |
g. botulism exotoxin |
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c. enterotoxins |
h. tetanus exotoxin |
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d. pertussis exotoxin |
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e. shiga toxin |