Mycobacterium tuberculosis

Question 1

Which proteins, secreted by the ESX1 T5SS, have WXG motifs and work together as a dimer

Answer 1

ESAT-6 AND CFP10

Question 2

Which proteins for lipid transport are amplified in the Mtb genome

Answer 2

Mmpt gene family

Question 3

How are Truncated haemoglobins in Mtb modified?

Answer 3

Glycosylation

Question 4

A catalase-periodoxase enzyme that degrades hydrogen peroxide (ROS) to water and oxygen

Answer 4

KatG

Question 5

Superoxide dimutase enzymes that degrade superoxide produced by IFN-gamma stimulated macrophages

Answer 5

SodA and SodC

Question 6

A reduced sulphur-containing compound that keeps the bacterial cytoplasm reduced when pH is low outside and there is oxidative stress from ROS

Answer 6

Mycothiol

Question 7

NADH-dependent peroxidase and peroxinitrate reductase

Answer 7

Degrades reactive oxygen and nitrogen species

Question 8

How does TrHbN overexpression interfere with host immunology

Answer 8

Suppressing CD80 and CD86 (interferes with T-cell activation by the macrophage)

Question 9

What is the result of glycosylated HbN surface expression

Answer 9

Optimal nitric oxide dioxygenase (NOD) function

Question 10

What are the two roles of truncated haemoglobins in Mtb

Answer 10

Detoxifying RNS and interfering with host immunology

Question 11

Which proteins in Mtb’s membrane are key for acid resistance

Answer 11

OmpATb proteins

Question 12

Which secretion systems mediate the rupture of phagosomal membranes inside host phagocytes

Answer 12

ESX-1

Question 13

Which secretion system is required for Mtb’s ability to move from the alveolar space into the lung interstitium

Answer 13

ESX-1

Question 14

Which secretion system secretes PE and PPE proteins including PE proteins with lipase domains to degrade host enzymes

Answer 14

ESX-5

Question 15

Which genes lie adjacent to PE-PPE genes in the same operon

Answer 15

ESX and ESAT-6

Question 16

What does 9% of the Mtb genome consist of

Answer 16

polymorphic tandemly repeated PE and PPE glycine-rich sequences

Question 17

Why do PE and PPE encoded antigens show high variation

Answer 17

Due to intragenic recombination and replication slippage due to their repeated sequences

Question 18

How do PE and PPE proteins give further antigenic variation

Answer 18

They dimerize on cell surfaces

Question 19

Mtb’s genome is GC-rich (65.6%), so which amino acids are rarely found in proteins?

Answer 19

Asparagine, Isoleucine, Phenylalanine, Lysine and Tyrosine (NIFKY)

Question 20

An lateral transfer of which genes caused Mtb to become pathogenic?

Answer 20

A PE-PPE gene pair into an ESAT gene cluster in a soil ancestor of mycobacterium

Question 21

What is current triple therapy for Mtb?

Answer 21

Isoniazid - inhibits mycolic acid synthesis
Flouroquinolones - affects DNA gyrase
Rifampicin - inhibits RNA polymerase
- Course is 6 months long

Question 22

What new drugs have been developed for Mtb?

Answer 22

• Delmanid - inhibits mycolic acid synthesis
• Pretomanid - causes nitric oxide synthesis and inhibits mycolic acid synthesis
• Bedaqualine - inhibits ATP synthesis by binding ATP synthase (fat-soluble)