7-2: Microbial Warfare Flashcards
How are antibiotics used in microbial warfare
Some bacteria (e.g. Streptomyces) produce/secrete small molecules that inhibit or kill bacteria
Where do streptomyces live? When are antibiotics produced?
Soil = competitive
During starvation to inhibit growth of competitors
What is the type VI secretion system (T6SS)
Essentially a syringe/needle to inject toxic proteins into competing bacteria
Species variation
Sometimes used on euk
Toxic proteins of type VI secretion systems. What is targeted?
T6SS effectors targets key cell structures (CW, membranes, DNA)
Why don’t bacteria type VI secretion system affect themselves with toxic proteins
Immunity protein is encoded immediately downstream, prevents self intoxication
What are bacteriocins
Protein toxins produced/secreted by certain bacteria
Similar to antibiotics bc they are secreted toxic molecules, similar to T6SS because they are toxic proteins targeting neighbouring cells
What protects bacteriocin secreted cells from bacteriocins
Immunity proteins produced
Some bacteriocins are…
Chemically modified proteins (aa of protein is modified by an enzyme)
How do bacteriocins cross OM and CM to access target
Have specific domains in toxic proteins
Yeast strains that produce toxins to kill other yeasts are…
killer yeasts
Eukaryotic microbes (“killer yeasts”) secrete protein toxins with two parts:
- Exhibits toxicity
- Triggers uptake into target cell
Killer toxins in euk encoded by..
viruses that infect the yeast
What commonly consumes and digests bacteria as primary food/energy source
Free-living amoeba
How do amoeba consume bacteria
Use temporary appendages called pseudopods to engulf bacteria
What happens once bacteria are engulfed by amoeba
Phagocytosed into a vacuole, fuses with lysozyme where bacteria are killed/digested
