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19 Cards in this Set
- Front
- Back
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What does Salmonella Typhimurium cause?
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gastroenteritis and fever
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What does Salmonella serovars (S. Typhi) cause?
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Typhoid fever: a severe systemic disease
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What does the salmonella typhimurinum infection in mice mimic in humans?
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The S. Typhi (typhoid fever) of humans
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What does Samonella Typhimurium use to combat the stomach's pH and acidic phagocytic vesicles of macrophages?
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50 acid shock proteins
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What three ways can acid shock proteins be induced?
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1. directly by acid
2. indirectly by other environmental stresses (ex. low O2) 3. by an iron regulatory protein, Fur, induced by low iron. |
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VIP VIP
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.
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Why aren't the salmonella bacteria killed by lysozomes once in the phagosome in the M cell?
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Salmonella inhibits the fusion of the lysosome.
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Describe in detail Salomonella's entry into the M cell using the three different types of type III secretory app?
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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! |
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Where are most of the genes required for invasion of the Salmonella found?
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In a pathogenicity island called SPI1 (salm path island 1)
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What are most of the genes found on the SPI1 (salm path island 1) and what do they do?
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They are: many inv and spa's
They encode a Type III secretory apparatus used to export Sip protein into the M cell. |
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Once inside the macrophage, what genes are repressed and what are expressed in Salmonella?
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prgHIJK - repressed
2CST (2-component signal transducion) - expressed |
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How does the bacteria sense it is inside the macrophage?
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Using the 2CST - 2-component signal transducion system
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What are the two components of the 2CST? (VIP)
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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. |
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If the aspartate binds on the DBD up stream - is it acting as a repressor or a promoter?
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Promoter
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If the aspartate binds on the promoter does it act as a promoter or repressor?
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Repressor
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VIP
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.
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VIP
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.
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Is prg required for survival in macrophage or to get into macrophage (and M-cell)?
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To get into
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Is PhoQP signalling required for virulence?
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Yes
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