Biology Reference
In-Depth Information
FIGURE 7.3 Intercellular spread of Shigella measured in the plaque assay. Bacteria are allowed
to invade a confluent monolayer of cells in tissue culture for 90 min. The monolayer is washed and
an overlay of 0.5% agarose-containing tissue culture medium with gentamicin is added and the
monolayers incubated for 48-72 h. The gentamicin kills extracellular bacteria. Plaques are formed
by intracellular bacteria that spread from cell to cell via protrusions that protect them from the
antibiotic. Top panel shows plaques formed by S. flexneri 2a in a monolayer of L2 fibroblasts after
48 h. Bottom panel shows the appearance of a plaque at higher magnification. The monolayer is
stained with neutral red, which stains living cells. Dead (unstained) cells can be seen in the center
of the plaque.
interaction between Atg5 and IcsA through competitive binding to IcsA ( Ogawa
et al., 2005 ). After 4 hours post-infection, 40% of the intracellular icsB mutants
are associated with autophagosome markers whereas only 8% of the wild-type
bacteria are recognized by the autophagy machinery ( Ogawa et al., 2005 ). IcsB
and Atg5 bind to the same internal region of IcsA (amino acids 320-433) but
Search WWH ::




Custom Search