Topic 1-9 (Lecture 9)

Question 1

What environmental factors control/affect the regulation of bacterial gene expression?

Answer 1

Temperature
Nutrients
Oxygen
Cellular pH
Iron availability
Osmolarity

Question 2

What are examples of process that are regulated (at a genetic level)?

Answer 2

Metabolism
Response to environmental stresses and conditions
Cell division

Question 3

What is a “global” regulatory system for virulence factors?

Answer 3

A regulatory system that controls multiple different virulence factors at once

Question 4

What is signal transduction?

Answer 4

The transmission of molecular signals from a cell’s exterior to its interior

Question 5

What system is commonly used to regulate virulence factors?

Answer 5

The two-component system

Question 6

How does the two-component system of signal transduction work?

Answer 6

1) A sensor kinase (protein that catalyzes phosphoryl transfer) detects changes in environment indicating it is residing within human host
2) Kinase phosphorylates a regulator protein (the second “component” of the two-component system)
3) Regulator protein becomes active, will activate or repress transcription of virulence factors (e.g. flagella genes, toxin genes, adhesin genes) by binding to DNA regulatory regions