Induction of stress responses.

<p>AB734 cells bearing single copy chromosomal fusions between the <i>lacZ</i> reporter gene and promoters induced by oxidative stress (<i>katG</i>), DNA damage (<i>sulA</i>), or cytoplasmic protein misfolding (<i>ibp</i>) were made competent and exposed to buffer (negative control) or the indicated chemical stressors. β-galacosidase activities were determined after 3h at 37°C and the magnitude of promoter induction was calculated by assigning a value of unity to the mean of negative controls. The β-galactosidase activity in cultures that had internalized BB-CT43-stabilized QDs supplied at 0.5 or 2.5 μg/mL was determined in a similar fashion. Error bars correspond to independent triplicate experiments.