Reading Review Questions – Chapter 13
The Power of Bacteria
As a tool to reinforce your reading of Chapter 13, please answer the following questions (only even numbered questions to reduce load).
2. Describe how you would show that putative translocated effector proteins from Salmonella were involved in inducing actin rearrangements, changing phosphorylation states of host proteins, and induction of apoptosis or DNA synthesis in host cells.
4. In the chapter, we mention that one advantage of direct delivery of toxic effectors into target host cells by the T3SS, T4SS, or T6SS is that the toxic effectors are able to avoid being neutralized by circulating antibodies. What other advantages does direct delivery of a toxic effector have for the pathogen?
6. You suspect that a newly discovered secretion system is important for virulence. How would you test this hypothesis? Keep in mind that mutations that disrupt an essential secretion system may kill the cell, thus making the bacterium appear less virulent.
8. You want to design a plasmid vector that would enable researchers to have their favorite protein(s) secreted by E. coli, even though that protein is not normally a secreted protein. Which of the secretion systems would you choose and why? Describe what this plasmid vector would entail?
10. How does the autotransporter secretory pathway differ from the other secretory pathways? Is the secretion mechanisms considered Sec-dependent or Sec-independent. Explain your answer.
12. Describe the mechanisms used by Gram-positive bacteria to retain proteins on their cell surfaces. Why are these mechanisms needed.
You do not need to address the “Solving Problems in Bacterial Pathogenesis” questions here.
Reading Review Questions – Chapter 14
The Power of Bacteria
As a tool to reinforce your reading of Chapter 14, please answer the following questions (only even numbered questions to reduce load).
2. Why would having regulated virulence genes be an advantage to a bacterium?
4. What type of mutation(s) would cause genes regulated by a two-component regulatory to be expressed constitutively?
6. Briefly describe the mechanisms by which Rho-dependent termination occurs.
8. Describe how the regulatory mechanism of “quorum sensing” might play a role in the pathogenesis of a Vibrio infection and how it works using the example of Lux (bacterial luminescence).
10. Bacteria adapt to changes in their environment and alter regulation of gene expression accordingly. One of the mechanisms of regulation in bacteria involves transduction of an environmental signal. Explain the function of bacterial sensors and transducers for gene regulation. How do two-component regulatory systems control gene expression in response to environmental changes? Give examples.
12. You are using a gene fusion between a very bad gene (vbg) and lacZ to study the regulation of vbg by iron. (When lacZ is expressed, cells are blue: when lacZ is not expressed, cells are white.) You introduce a transposon into the strain carrying a vbg-lacZ fusion and screen for regulatory mutants. You conclude that vbg is expressed in the presence of iron because you observe that, for the wildtype fusions, colonies are ________ in the presence of iron and ______ in the absence of iron. You conclude that the transposon has been inserted into a gene encoding the activator protein because you observe that the colonies are __________ in the presence of iron and ________ in the absence of iron.
a. blue…white….blue…blue
b. white…blue….blue…blue
c. blue…white….white…white
d. white…blue….white…white
e. white…blue….white…blue
Select any problem from the section “Solving Problems in Bacterial Pathogenesis” in your textbook and solve the problem. Explain your work.
