Module 2: Section 2B

Question 1

How pili enhance bacterial infection

Answer 1

• Help bacteria stick to host cells and form biofilms
• Within biofilms, bacteria are protected from the immune system
• Biofilms allow bacteria to release enzymes that damage host cells
• Ex: Enterococcus faecalis uses this process to cause endocarditis

Question 2

3 steps of how phage use pili to infect a bacterial cell

Answer 2

1. Attachment
2. Retraction
3. Uncoating and penetration

Question 3

1. Attachment - phage use pili to infect a bacterial cell

Answer 3

• Phages interact with the tip or side of bacterial pili
• Initial interaction tethers the phage to the bacterium

Question 4

2. Retraction - phage use pili to infect a bacterial cell

Answer 4

Retraction of pili brings phage in close proximity with the bacterial cell

Question 5

3. Uncoating and penetration - phage use pili to infect a bacterial cell

Answer 5

• Phage can now interact with other membrane proteins
• Can also use pili basal structure to inject its genetic material into the cell

Question 6

Phage therapy

Answer 6

• Phages can be delivered to the lungs to treat chronic infections
• Once inside, they infect bacteria, replicate, and lysis, releasing more phages
• If no bacteria are present, phages are cleared by the immune system