Topic 7- L2 - Microbial warfare

Question 1

The production of antibiotic by streptomyces is done during

Answer 1

Starvation, produced to inhibit growth of competitors to allow them to complete sporulation process?

Question 2

Type VI secretion systems (T6SS)

Answer 2

Needle that inject StockX proteins into competing bacteria, need close contact. Presence depends on strain.

Question 3

Toxic proteins called

Answer 3

“T6SS effectors”

Question 4

Immediately downstream of being injected by toxic protein by T6SS,
an

Answer 4

immunity protein is encoded to protect against self-intoxication

Question 5

Effectors (T^SS effector) target (often

degrade) key cellular structures –

Answer 5

cell wall, membranes, DNA

Question 6

T6SS related to system used by

Answer 6

phage to inject their DNA into bacteria

Question 7

Bacteriocins are

Answer 7

protein toxins produced/secreted by certain bacteria

Change depending on strain

Question 8

Bacteriocins Similar to

Answer 8

antibiotics (secreted toxic molecules) and T6SS (toxic proteins to target neighbouring cells)

Question 9

Bacteriocins have a lot of variability and target

Answer 9

cell wall, cell membrane, nucleic acids, etc

Question 10

Some bacteriocins are

Answer 10

chemically modified proteins (enzymes modify amino acids)

• used for food preservation (Nisin)

Question 11

“Killer Yeasts” –

Answer 11

yeast strains that produce toxins that kill other yeasts

They are killer toxins

Question 12

Secreted protein toxins typically have two parts:

Answer 12

One part exhibits toxicity

other part triggers uptake into target cells

Question 13

Killer toxins have

Answer 13

Immunity to toxins and impact fermentation

Question 14

Free-living amoeba (eukaryotic) eat bacteria by using

Answer 14

temporary appendages called
pseudopods - also used for movement - to engulf bacteria

Then fused with lysosome

Question 15

Legionella pneumophila (gram -) causes

Answer 15

Legionnaires’ disease is a form of pneumonia (infection that
leads to lung inflammation)

Question 16

The natural reservoir for Legionella are

Answer 16

aquatic amoeba - they have evolved to survive after being consumed by these amoeba, by manipulating the biology of the amoeba

Question 17

After engulfment, Legionella pneumophila

Answer 17

avoid fusion with lysosomes – sculpt intracellular niche called a Legionella containing vacuole (LCV).

allow Legionella to survive when engulfed by
human immune cells!

Question 18

L. pneumophila uses a

Answer 18

type IV secretion system to inject specific effector proteins into amoeba (cells of “accidental hosts” like humans)

Question 19

Effector proteins manipulate host cell biology in several different ways to
enable Legionella to establish a

Answer 19

replicative niche (LCV) within these cells