Deploying FLAREs to Visualize Functional Outcomes of Host-Pathogen Encounters

Two functional microbial reporters have been used to distinguish active invasion from phagocytic uptake.\n The feasibility of these genetic manipulations depends on the ease with which the target microbe can be mutated. Since genetically encoded fluorophores can be sensitive to environmental conditions, for example, ambient oxygen concentrations in host tissues [12], it is imperative to define the readouts of these functional microbial reporters under in vitro and in vivo conditions. The mechanism by which DsRed and other genetically encoded fluorophores are quenched and degraded within mammalian phagosomes remains poorly defined. [...]the strict correlation between loss of fluorescence in sorted leukocyte populations and loss of microbial viability, as measured by colony-forming unit analysis, is critical to the success of the FLARE approach.