BioSc 321 Pathogenic Microbiology
Exam 4
Due 12//22003
Bordetella pertusis produces two toxins that impact cAMP production. Describe the typical mechanism of
cAMP production in host cells and compare the different mechanisms by which the two toxins lead to elevated
cAMP production. What possible advantage might the bacteria derive from elevated cAMP levels?
Describe the classic Avery, McLeod and McCarty experiments with Streptococcus pneumoniae which
demonstrated that DNA is the genetic material. The avirulent strains used in their experiments were avirulent
because they were now susceptible to host defenses. Describe all the defenses to which the avirulent bacteria
are now susceptible.
In your textbook chapter on Tuberculosis, a proposed chemotherapy target is isocitrate lyase. Explain the role
of isocitrate lyase in the metabolism of the bacterium and the reason why it might be an effective target.
Discuss the merits of such a targeted drug design.
An outbreak of respiratory infections is occurring in Hereford, in western England. Legionnaire’s disease is
the suspected cause. What factors would you look for (patient history, symptoms, etc.) to support this
diagnosis? Where would you look for the source of the outbreak and how would you test to confirm the
source?
Compare Mycoplasma pneumoniae and Chlamydia pneumoniae. i.e. the diseases they cause, their life cycles,
characteristics, etc. and how these characteristics might be used to distinguish the cause of a respiratory
infection.
Researchers at Harvard school of medicine have been working on drugs to battle infections with Bacillus
anthracis They are taking two approaches, focusing the interaction of the anthrax toxins with their target
cells. One approach is to inject a person with a copy of the host cell receptor protein and the other is to inject
a person with a defective copy of the protective antigen. Predict the effect of each of these injected proteins
on the activity of the anthrax toxin. It has also been discovered that injection of the defective copy of the
protective antigen has the added advantage of inducing immunity to anthrax. Speculate on the reason for the
immunogenic effect of the defective protective antigen.