203 L17 Flashcards
Exotoxins and exoenzymes
Exotoxins are —— produced by the bacteria and secreted into the ——–, causing ——- to the host
Proteins produced by the bacteria and secreted into environment, causing damage to the host
Exotoxins can lead to the ————- of ———– processes which is not —— damage so there can be complete cell ——— or ——- (controlled).
Exotoxins can lead to direct cell ——- and cause ——- (not controlled) or ——– (controlled)
Degradative enzymes don’t ———-. They cause ——– damage leading to ———. Some of the enzymes can target part of our immune response - e.g. complement proteins. This leads to an immune evasion effect.
Exotoxins can lead to the deregulation of cellular processes which is not cell damage so there can be complete cell recovery or apoptosis (controlled).
Exotoxins can lead to direct cell damage and cause necrosis (not controlled) or apoptosis (controlled)
Degradative enzymes don’t deregulate. They cause tissue damage leading to necrosis. Some of the enzymes can target part of our immune response - e.g. complement proteins. This leads to an immune evasion effect.
An infectious disease is when a ——– colonises a person’s body and ——— inside the host causing a disease.
An infectious disease is when a pathogen colonises a person’s body which proliferates inside the host causing a disease.
In microbial intoxication a ——– produces a —– in vitro and is ——– by the person which causes the disease. The bacteria that produce the toxin don’t have to be present.
In microbial intoxication a pathogen produces a toxin in vitro and the toxin is ingested by the person which causes the disease. The bacteria that produce the toxin don’t have to be present.
Cholera toxin
The cholera toxin belongs to the —– toxin family - — subunits = — subunit and —- subunit. The —- subunit goes together with – —- subunits.
The — — subunits build a ring structure that recognises a certain ——– on the surface of the ——— epithelial cells. This causes the toxin to be ———– into the cell move through the golgi and into the ———– ——– where the — subunit ——- and gets transported into the ——– to find its target. The target for the —- subunit is stimulatory — ——- (transducer). When the —- subunit binds to the —– protein it signals ——– ——– (effector) to cleave ——– to form ——– (intracellular messenger) which has a downstream effect on ———- (——— channel). The toxin leads to an over production of —— and that high amount of ——– keeps the ——— channel open, so alot of ———- is pumped into the ——— resulting in an ——– imbalance. Therefore the positive ———– ions follow resulting in an ———- imbalance. Therefore ——— moves into the lumen as well resulting in ———–.
Cholera toxin
The cholera toxin belongs to the Ab5 toxin family - 2 subunits = a subunit and b subunit. The a subunit goes together with 5 b subunits.
The 5 b subunits build a ring structure that recognises a certain receptor on the surface of the intestinal epithelial cells. This causes the toxin to be endocytosed into the cell move through the golgi and into the endoplasmic reticulum where the a subunit dissociates and gets transported into the cytosol to find its target. The target for the a subunit is stimulatory G proteins (transducer). When the a subunit binds to the G protein it signals adenylate cyclase (effector) to cleave ATP to form cAMP (intracellular messenger) which has a downstream effect on CFTR (chloride channel). The toxin leads to an over production of cAMP and that high amount of cAMP keeps the chloride channel open, so alot of chloride is pumped into the lumen resulting in an electrostatic imbalance. Therefore the positive sodium ions follow resulting in an osmotic imbalance. Therefore water moves into the lumen as well resulting in diarrhea
G protein
The g protein has — subunits - ——, ——-, ——- which have ———— change when a ligand binds to the receptor.
The ———- subunit fits into the ——— and the ——– is exchanged for a ——- which leads to a conformational change of the G protein which can now bind to ——- ——– and stimulate it converting —— to ——-. —— then dissociates back into —– to erase the signal.
The g protein has 3 subunits - alpha, beta, gamma which have conformational change when a ligand binds to the receptor.
The gamma subunit fits into the receptor and the GDP is exchanged for a GTP which leads to a conformational change of the G protein which can now bind to adenylate cyclase and stimulate it converting ATP to cAMP. GTP then dissociates back into GDP to erase the signal.
The —– subunit of the cholera toxin is an ——–, ADP ribosyltransferase. It recognises —— and it cleaves it to release the —— —-from the nicotinamide. It then transfers the —– ——- onto the ——– subunit of the G protein covalently. Therefore the ——– cannot dissociate anymore and there is a constant activation of the —– —— and constant ——– production. High levels of —– effects the ——-, causing active secretion of —–, with —– ions and ——- following.
The A subunit of the cholera toxin is an enzyme, ADP ribosyltransferase. It recognises NAD+ and it cleaves it to release the ADP ribose from the nicotinamide. It then transfers the ADP ribose onto the alpha subunit of the G protein covalently. Therefore the GTP cannot dissociate anymore and there is a constant activation of the adenylate cyclase and constant cAMP production. High levels of cAMP effects the CFTR and causes active secretion of Cl-, with sodium ions and water follwing.
Shiga like toxin
The shiga like toxin belongs to the —- toxin family - — subunits = —- subunit and —- subunit. The —- subunit goes together with — — subunits.
The — — subunits build a ring structure that recognises a certain —— on the surface of the ——– epithelial cells. This causes the toxin to be ———– into the cell move through the golgi and into the ——— ——— where the —— subunit dissociates and gets transported into the —— to find its target. It targets the 28S ——— in the ——–, changing a ——– so the ——– doesn’t work anymore. The ——– translation stops, the cells go into ——– and start an ——– process
The shiga like toxin belongs to the Ab5 toxin family - 2 subunits = a subunit and b subunit. The a subunit goes together with 5 b subunits.
The 5 b subunits build a ring structure that recognises a certain receptor on the surface of the intestinal epithelial cells. This causes the toxin to be endocytosed into the cell move through the golgi and into the endoplasmic reticulum where the a subunit dissociates and gets transported into the cytosol to find its target. It targets the 28S rRNA in the ribosome, changing a nucleotide so the ribosome doesn’t work anymore. The protein translation stops, the cells go into stress and start an apoptotic process
Shiga like toxin
The shiga like toxin belongs to the —- toxin family - — subunits = —- subunit and —- subunit. The —- subunit goes together with — — subunits.
The — — subunits build a ring structure that recognises a certain —— on the surface of the ——– epithelial cells. This causes the toxin to be ———– into the cell move through the golgi and into the ——— ——— where the —— subunit dissociates and gets transported into the —— to find its target. It targets the 28S ——— in the ——–, changing a ——– so the ——– doesn’t work anymore. The ——– translation stops, the cells go into ——– and start an ——– process
The shiga like toxin belongs to the Ab5 toxin family - 2 subunits = a subunit and b subunit. The a subunit goes together with 5 b subunits.
The 5 b subunits build a ring structure that recognises a certain receptor on the surface of the intestinal epithelial cells. This causes the toxin to be endocytosed into the cell move through the golgi and into the endoplasmic reticulum where the a subunit dissociates and gets transported into the cytosol to find its target. It targets the 28S rRNA in the ribosome, changing a nucleotide so the ribosome doesn’t work anymore. The protein translation stops, the cells go into stress and start an apoptotic process
Direct cell damage by cytolysins
These are ——— secreted by the bacteria in a soluble form
They bind to a receptor and ——- to form a ——–. This damages the ——— function so the cell can influx water and burst
Cytolysins that target RBC are called ———.
These are exotoxins secreted by the bacteria in a soluble form
They bind to a receptor and oligomerise to form a pore. This damages the barrier function so the cell can influx water and burst
Cytolysins that target RBC are called hemolysins
Direct cell damage by cytolysins
These are ——— secreted by the bacteria in a soluble form
They bind to a receptor and ——- to form a ——–. This damages the ——— function so the cell can influx water and burst
Cytolysins that target RBC are called ———.
These are exotoxins secreted by the bacteria in a soluble form
They bind to a receptor and oligomerise to form a pore. This damages the barrier function so the cell can influx water and burst
Cytolysins that target RBC are called hemolysins
Degradative enzymes are —— secreted by the bacteria into the ———–.
Degradative enzymes are proteins secreted by the bacteria into the environment.
Lipases are enzymes that target ——-.
Proteases are enzymes that target ——–.
DNAses are enzymes that target —-.
Lipases are enzymes that target lipid.
Proteases are enzymes that target proteins.
DNAses are enzymes that target DNA.
Lipases are enzymes that target ——-.
Proteases are enzymes that target ——–.
DNAses are enzymes that target —-.
Lipases are enzymes that target lipid.
Proteases are enzymes that target proteins.
DNAses are enzymes that target DNA.
