Introduction

Question 1

BEFORE ingestion, intestinal pathogens often reside in water AT (4-furlough)….

Answer 1

1. at a low temperature (cold)
2. at low ionic strength
3. at near-neutral pH (noot)
4. at low concentration of organic nutrients (no food)

Question 2

AFTER ingested, pathogens must adapt TO (5-oh so high as a kite)…

Answer 2

1. higher temperature
2. higher osmotic strength
3. LOW pH in the STOMACH
4. HIGH pH, bile salts, lack of oxygen, and abundant organic nutrients in the INTESTINE
5. host sequesters virtually all of its iron making it unavailable to the pathogen

Question 3

To SURVIVE this journey, pathogens must rapidly express a variety of gene products…cinqo de mayo

Answer 3

1. IRON CHELATOR (higher affinity than host’s) to scavenge for iron…SIDEPHORES
2. Proteins that permit it to tolerate low pH in the stomach
3. FLAGELLA and CHEMOTAXIS PROTEINS that allow to migrate to a suitable niche
4. ADHESINS that permit it to colonize the intestine
5. TOXINS and INVASINS that permit it to elicit disease and free up nutrients

Question 4

But how/who do I fux with?!

Answer 4

specific “virulence genes” must be turned on to adapt to each of these conditions or to perform each of these tasks. SIMULTANEOUSLY, other genes must be turned OFF.