Bacterial Toxins and Dehydration Flashcards
Mechanisms for enhancing in vivo protein folding; benefits and risks associated with in vivo folding
s
Components of phospholipids, glycolipids, cholesterol
k
Structure of carbohydrates on glycoproteins and glycolipids; orientation in relation to cytoplasm
the molecule recognized by the B portion is the carbohydrate moiety of a host cell surface glycoprotein or Gleicher lipid, but some be portions bind to proteins; if a certain glycoprotein is found only on the surface of neurons, the toxin will work there.
E. coli Toxin Mechanism of Action
Heat Labile (LT): Increases excretion of chloride ions
Heat Stable (ST): Increases diverse ion pump functions
Shiga toxin (stx)
Ion efflux stimulates water secretion outside of the cell
Loss of ions into lumen of gut, causes a loss of water to the gut as well.
If ions flow across a membrane, water follows
Functions of protein pores, channels, transporters
Pore insertion into the plasma membrane allows unregulated flow of both water and ions
Normally:
K+ high intracellularly
Na+ low intracellularly
Pore insertion allows K+ to flow out and Na+ to flow into the cells
Water will also flow unregulated into the cell, causing it to swell
Membrane permeability
s
Effects of osmotic pressure and water transport (into and out of cells, through the blood)
s
Changes in ligand transport and osmotic pressure (SGLT)
SGLT transports glucose
Relies on Na gradient
Relationship of transport of water and ions across the erythrocyte membrane and cell shape
s
Hypertonic, isotonic, hypotonic compared to plasma
s
How does osmolarity influence fluid movement within body compartments?
s
Signs of dehydration in pediatric patients and appropriate treatment
s
Signs of dehydration in pediatric patients and appropriate treatment
Increased heart rate (Tachycardia) is the earliest clinical manifestation
Other signs of more severe dehydration:
- altered mental status
- decrease in BP
- increase in RR
- decrease skin turgor
Class 3 Toxins
Form pores in membrane
Diphtheria toxin Cholera toxin Anthrax Botulinum Tetanus
They have a conformational change from a soluble, globular structure to a membrane inserted structure
Endosome is acidified by proton pump
Drop in pH triggers conformational change in one subunit
Histidine has an ionizable side chain in the pH range of neutral to acidic, could be perfect for pore formation
Diptheria toxin Mechanism
Bind to host membrane-bound receptors and enter cells via receptor-mediated endocytosis
Endosome acidification
A domain is translocated into cytosol by insertion into endosomal membrane and reduction of disuphide bond
A domains of DT-like toxins ADP-ribosylate elongation factor 2 (EF2) which inhibits protein synthesis and kills the cell
