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19 Cards in this Set

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  • Back
What does Salmonella Typhimurium cause?
gastroenteritis and fever
What does Salmonella serovars (S. Typhi) cause?
Typhoid fever: a severe systemic disease
What does the salmonella typhimurinum infection in mice mimic in humans?
The S. Typhi (typhoid fever) of humans
What does Samonella Typhimurium use to combat the stomach's pH and acidic phagocytic vesicles of macrophages?
50 acid shock proteins
What three ways can acid shock proteins be induced?
1. directly by acid
2. indirectly by other environmental stresses (ex. low O2)
3. by an iron regulatory protein, Fur, induced by low iron.
What do Sip proteins do?
Send signals to eukaryotic cells that causes M cell invasion by modifiying LPS which causes a release of TNF alpha and synthesis of E-selectin. This causes host cell to bind more tightly to Salmonella. These also induce the cell to produce ruggles and do phagocytosis.
Why aren't the salmonella bacteria killed by lysozomes once in the phagosome in the M cell?
Salmonella inhibits the fusion of the lysosome.
Describe in detail Salomonella's entry into the M cell using the three different types of type III secretory app?
Type III-1 app: injects Sip proteins into the M-cell causing ruffle and phagosome formation
Type III-2: secretes proteins from within the phagosome out into the M-cell's cytoplasm that blocks fusion any lysosomes.
Type III-3: (This is encoded by SPI1's prgHIJK genes) Injects bacterial proteins into macrophages to facilitate phagocytosis - giving Salmonella access to the blood!
Where are most of the genes required for invasion of the Salmonella found?
In a pathogenicity island called SPI1 (salm path island 1)
What are most of the genes found on the SPI1 (salm path island 1) and what do they do?
They are: many inv and spa's

They encode a Type III secretory apparatus used to export Sip protein into the M cell.
Once inside the macrophage, what genes are repressed and what are expressed in Salmonella?
prgHIJK - repressed
2CST (2-component signal transducion) - expressed
How does the bacteria sense it is inside the macrophage?
Using the 2CST - 2-component signal transducion system
What are the two components of the 2CST? (VIP)
1. sensor - histidine autokinase (receptor) that is membrane bound as autophosphorylates using ATP AS A PHOSPHODONOR

2. response regulator: aspartate autokinase which is a DNA binding protein that autophosphorylates on aspartate (it takes the P off of the sensor and puts it on the aspartate). The prescence of the P changes the shape of the DBD allowing the regulator to bind. This can activate or repress depending on which DNA binding domain the aspartate is on.
If the aspartate binds on the DBD up stream - is it acting as a repressor or a promoter?
If the aspartate binds on the promoter does it act as a promoter or repressor?
In salmonella what is the name of the histidine-kinase sensor? What does it sense?
Sensor: PhoQ - it senses low Mg conc found uniquely within the macro phagosome. Says "we are in the macrophage!" and it autophosphorylates itself.
In salmonella what is the name of the response regulator? What does it activate and repress?
Response regulator: PhoP - it represses genes for invasion into Mcells and macrophages (prg) while simultaneoulsy activating genes for survival inside the macrophage (pag). So the PhoP steals the P off ProQ to activate/repress genes.
Is prg required for survival in macrophage or to get into macrophage (and M-cell)?
To get into
Is PhoQP signalling required for virulence?