Figure 1
From: Selenite reduction by Shewanella oneidensis MR-1 is mediated by fumarate reductase in periplasm
Effect of extracellular respiratory system on selenite reduction by S. oneidensis MR-1.
(A) Selenite reduction rates of the wild-type strain and the extracellular respiratory proteins mutants. Both MtrA-MtrB-MtrC/OmcA and its functional analogue MtrD-MtrE-MtrF were examined for their contributions to selenite reduction. Periplasmic c-type cytochrome MtrA and MtrD were also studied here for integrity. Dual deletion of omcA and mtrC was constructed for their functional similarity in electron transfer. The reduction ability of all the mutants is expressed as the average rate (calculated over the linear portion of the kinetics curve, based on 4 time points) of selenite reduced in μmol h−1. The adjust (Adj.) R2 of each fitting were 0.9129, 0.8580, 0.9267, 0.9915, 0.9120, 0.8549. Error bars indicate the standard error of triplicate cultures; and (B) Effect of extracellular flavins to selenite reduction. FMN, instead of riboflavin, was dosed to the reduction culture of the wild-type and mutants, as MR-1 directly secreted FMN outside and riboflavin is in the form of hydrolyzate. The reduction ability is expressed as the average rate (calculated over the linear portion of the kinetics curve) of selenite reduced in μmol h−1.WT-0, wild-type without FMN dose; WT-1, wild-type with 1 μM FMN; ΔushA, ushA mutant without FMN dose; FMN, non-cells control with 10 μM FMN. The Adj. R2 of each fitting were 0.8640, 0.7816, 0.9978, 0.7962. Error bars indicate the standard error of triplicate cultures.
