Vibrio cholerae Flashcards
(6 cards)
Describe the geographical distribution of pandemic Vibrio cholerae strains
South asia
Sub-saharan africa
Haiti and caribbean
yemen
south america
Provide details for the England epidemic
Occurred during the 1846-1860 cholera pandemic
Happened in Soho distract of Westminster, London
Killed 616 people
John Snow identified water pump as source and removed the handle
Ended the outbreak
Considered a founding event in epidemiology
Provide details for the Haitian epidemic
Cholera broke out ten months after the earthquake
Approx. 600k cases and 7k deaths in Haiti
20k cases in the Dominican Republic
Suspected to have come from Kathmandu due to almost identical isolates
Describe the role of phage CTXØ in acquisition of cholera toxin (CT)
Attaches to TCP, which is expressed under virulence inducing conditions
Enters using this pilus as a receptor
ssDNA is converted to dsDNA
Integrates at specific sites within the genome
Carries ctxAB operon
Encodes for CtxA (A subunit of toxin) and CtxB (B subunit of toxin)
Becomes toxigenic
Explain the molecular function of CT and how it causes watery diarrhea in the host
AB5 toxin
Binds GM1 receptors, triggers endocytosis
ACtivates Gas regulatory protein in cytosol, produces cAMP
cAMP iactivates PKA
PKA interferes with ion homeostasis - phosphophorylation of NHEs and CFTR
Loss of ion homeostasis compromises H2O resorption - watery diarrhea
Provide molecular details about the type VI secretion system and its delivery of toxic effectors to prokaryotic cells
Comprised of proteins that are structural homologs of bacteriophage tail-like proteins
13 genes in assembly/function
Contractile sheath, tail tube, and base plate and tail spike
Crystallized Hcp forms hexameric rings that stack in tubes with a 40 Å channel
Same fold as lambda phage tube protein
