MELS223 Lecture Notes - Lecture 13: Listeriolysin O, Cytosol, Glycogen Phosphorylase
6 Sep 2013
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Document Summary
Antimicrobial properties of phagocytes: low phagosomal ph (v-atpase, production of reactive oxygen species (ros, cationic antimicrobial peptides (camps, acquisition of proteases (e. g. cathepsins) Examples are superoxide anion and hydroxyl radical. Have an unpaired electron, making them highly reactive. Damage macromolecules (dna, protein, lipids) by oxidation. Killing of bacteria by cationic antimicrobial peptides (camps) Outer membrane and/or inner membrane of bacterium. - binds and destroys membrane. Intracellular survival of microbial pathogens: survival in an acidic compartment (salmonella, avoidance of fusion with lysosome (legionella, mycobacterium, escape from vacuole (listeria, shigella) Salmonella resides in a remodeled" lysosomal compartment (ph is acidic, but not as acidic as a normal lysosome) Intracellular survival requires two type iii secretion systems (ttss1 and ttss2) Other virulence factors needed for intracellular survival are: superoxide dismutase (sod, phop/phoq and pmra/pmrb two component regulatory systems. Superoxide dismutase and catalase protect salmonella from ros. Pmra/pmrb protect against killing by camps by covalently modifying lps.
