Tellurite Enters Escherichia Coli Mainly Through the Pita Phosphate Transporter

Several transporters suspected to be involved in tellurite uptake in Escherichia coli were analyzed. Results showed that the PitA phosphate transporter was related to tellurite uptake. Escherichia coli ?pitA was approximately four-fold more tolerant to tellurite, and cell viability remained almost unchanged during prolonged exposure to the toxicant as compared with wild type or ?pitB cells. Notably, reduced thiols (toxicant targets) as well as superoxide dismutase, catalase, and fumarase C activities did not change when exposing the ?pitA strain to tellurite, suggesting that tellurite-triggered oxidative damage is attenuated in the absence of PitA. After toxicant exposure, remaining extracellular tellurite was higher in E. coli ?pitA than in control cells. Whereas inductively coupled plasma atomic emission spectrometric studies confirmed that E. coli ?pitA accumulates ~50% less tellurite than the other strains under study, tellurite strongly inhibited 32Pi uptake suggesting that the PitA transporter is one of the main responsible for tellurite uptake in this bacterium. © 2012 The Authors. MicrobiologyOpen published by Blackwell Publishing Ltd.