The widespread use of quantum dots (QDs) in numerous applications increases the possibility of their release to the environment.  Since bacteria are the basis of all known ecosystems, understanding their response to QDs is important to discern adaptation mechanisms. Both weathered and intact QDs as well as dissolved metal salts up-regulated the expression of metal efflux transporters czcABC in P. aeruginosa. Weathered QDs also induced superoxide dismutase gene sodM, suggesting a defense against oxidative stress. Extracellular synthesis of NPs, containing Cd and Se, were detected after the exposure to dissolved Cd(NO3)2 and SeO2 salts. With EXAFS, we determined biogenic nanoparticles such as CdO, CdS, CdSe and selenium sulfides. These results suggest that bacteria can mitigate QD toxicity by turning on energy dependent heavy-metal ion efflux systems and by decreasing metal bioavailability by promoting redox state changes and precipitation of metal ions as insoluble NPs.

Transcriptional response and potential defense mechanisms of <i>Pseudomonas aeruginosa</i> exposed to quantum dots

243rd National Meeting (2012)

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Transcriptional response and potential defense mechanisms of Pseudomonas aeruginosa exposed to quantum dots