Flashcards
Bacterial Pathogenesis II
Flashcards do conjunto (25)
- 1What is an exotoxin?Actively participates in host cell cellular disruption and damage.
- 2EndotoxinsPassively participate in host damage caused by an excessive response by host innate immune system to presence of endotoxin
- 3What are the general properties of exotoxins?Soluble protein, gram +ve or -ve, can be important virulence factor, gene carried in plasmid of prophage
- 4How do exotoxins help invade the IS?Aid infection, transmission and obtaining host cell nutrients
- 5What is the extracellular effect of exotoxins?Affect cellular junctions and structure
- 6Cell membrane effect of exotoxins?Superantigen (bind cell receptors) and cytolytic toxins (disrupt cell membrane)
- 7What are the effects of exotoxins within cells?Cytotonic toxins, cytotoxic toxins and neurotoxins
- 8What is the role of superantigens?Toxin that bridges MHC of antigen presenting cell with T cell in a non-specific manner -> non-specific B cells and antibodies and SHOCK
- 9How do cytolytic toxins work?Proteolysis, direct lysis of cell membrane, pore forming, detergents -> holes in membrane leading to lose of control of osmotic balance -> cell lysis
- 10What are the two main strategies that exotoxins can cross the cell wall?Binary molecule (A-B toxins) or direct delivery
- 11How to Type III and Type IV secretory molecules work in direct transfer?After contact with host. Type III injects toxins and Type IV transfer similar to DNA transfer via sex pillus
- 12Some examples of A-B toxins?Diphtheria, cholera toxin and tetanus neurotoxin
- 13What is the mode of action of cytotonic toxins?Raises level of cAMP by disrupting its turnover -> raised movement of cations through cell membrane and consequently excessive water loss
- 14Where is the site of action of cytotonic exotoxins?GI tract -> diarrhoea and dehydration
Lung -> excessive cough reflex - 15What is the mode of action of cytotoxic toxins?Causes cell death by inhibiting protein synthesis or disrupting intracellular signalling
- 16Site of action of cytotoxic toxins?Widespread, any cell that is infected or can mount an immune response
- 17What is the mode of action of neurotoxins?Disrupt nervous system by inhibiting release of neurotransmitter into synaptic cleft
- 18What are the sites of action of neurotoxins?BOTULINUM TOXIN -> peripheral NS causing decreased excitatory neurotransmitter -> flaccid paralysis
TETANUS -> CNS decreased inhib neurotransmitter -> spastic paralysis - 19Do exotoxins need to be inactivated before vaccination?YES
- 20What are the general properties endotoxin?Lipopolysaccharide with a gram -ve cell wall
- 21What does LPS induced inflammatory response cause?Inflammatory cytokines, lipid free radicals, activation of complement and coagulation cascade. If increase infection/dissemination -> SEPTIC SHOCK
- 22What does excessive inflammatory response lead to?Increase in arteriolar dilation and vascular permeability -> hypotension. Decrease in cardiac output and perfusion of all but vital organs
- 23What does excessive activation of complement lead to?Excessive anaphylatoxins -> proinflamm response. Non-specific endothelial cell damage -> increase vascular permeability
- 24Excessive activation of coagulation cascade leads to...Kinin release -> increase vascular permeability and leucocyte activation. DIC -> tissue damage
- 25What are the end results of sepsis?Septic shock, multiple organ dysfunction-> failure and DEATH
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- I & I: Virology FlashCards sobre Bacterial Pathogenesis II, criado por priya.j.patel em 24-03-2014.
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- priya.j.patel
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