Insight into the primary mode of action of TiO2 nanoparticles on Escherichia coli in the dark.
Large-scale production and incorporation of titanium dioxide nanoparticles (NP-TiO2 ) in consumer products leads to their potential release into the environment and raises the question of their toxicity. The bactericidal mechanism of NP-TiO2 under UV light is known to involve oxidative stress due to the generation of reactive oxygen species. In the dark, several studies revealed that NP-TiO2 can exert toxicological effects. However, the mode of action of these nanoparticles is still controversial. In the present study, we used a combination of fluorescent probes to show that NP-TiO2 causes Escherichia coli membrane depolarization and loss of integrity, leading to higher cell permeability. Using both transcriptomic and proteomic global approaches we showed that this phenomenon translates into a cellular response to osmotic stress, metabolism of cell envelope components and uptake/metabolism of endogenous and exogenous compounds. This primary mechanism of bacterial NP-TiO2 toxicity is supported by the observed massive cell leakage of K(+) /Mg(2+) concomitant with the entrance of extracellular Na(+), and by the depletion of intracellular ATP level.
['Sohm|Bénédicte|B|', 'Immel|Françoise|F|', 'Bauda|Pascale|P|', 'Pagnout|Christophe|C|']
D000255:Adenosine Triphosphate D004926:Escherichia coli D029968:Escherichia coli Proteins D008274:Magnesium D050296:Microbial Viability D053758:Nanoparticles D009997:Osmotic Pressure D010539:Permeability D011188:Potassium D012964:Sodium D014025:Titanium D059467:Transcriptome
Escherichia coli Titanium dioxide nanoparticles Toxicity Transcriptomics Osmotic stress Microbiology