Corrigendum to 'Amyloid adhesin production in activated sludge is enhanced in lab-scale sequencing batch reactors: Feeding regime impacts microbial community and amyloid distribution' [Water Research X 17 (2022) 100162].

[This corrects the article DOI: 10.1016/j.wroa.2022.100162.].

Amyloid adhesin production in activated sludge is enhanced in lab-scale sequencing batch reactors: Feeding regime impacts microbial community and amyloid distribution.

Amyloid adhesins are ß-sheet-rich extracellular proteins thought to contribute to bioflocculation. They are present in activated sludge to varying extent. However, it remains unclear which operational conditions promote their production. To this end, the abundance and distribution of amyloids and their potential producers were monitored in two lab-scale reactors operated in sequencing batch mode with an unaerated and aerated reaction phase. Various feeding regimes ranging from feast-famine to nearly continuous feeding were applied. Thioflavin T staining revealed more amyloids in the lab-scale reactors during all operational stages compared to the full-scale industrial and municipal inocula. Furthermore, the feeding regime impacted the distribution of produced amyloids from dense clusters during feast-famine conditions towards a dispersed distribution during nearly continuous feeding. This dispersed presence did not negatively impact the bioflocculation (towards average floc size and shear sensitivity). 16S rRNA sequencing detected several known EPS and amyloid producers. More continuous and, hence, partially aerobic feeding promoted the relative abundance of denitrifiers. Sequential Thioflavin T staining and fluorescence in situ hybridization identified Zoogloea and Ca. Competibacter as potential amyloid producers under the applied conditions. This experiment confirms that amyloid producers need to be triggered for production and that the feeding regime impacts the microbial community composition, which in turn influences the amyloid production and distribution.

Effects of beta-band and gamma-band rhythmic stimulation on motor inhibition.

To investigate whether beta oscillations are causally related to motor inhibition, thirty-six participants underwent two concurrent transcranial alternating current stimulation (tACS) and electroencephalography (EEG) sessions during which either beta (20 Hz) or gamma (70 Hz) stimulation was applied while participants performed a stop-signal task. In addition, we acquired magnetic resonance images to simulate the electric field during tACS. 20 Hz stimulation targeted at the pre-supplementary motor area enhanced inhibition and increased beta oscillatory power around the time of the stop-signal in trials directly following stimulation. The increase in inhibition on stop trials followed a dose-response relationship with the strength of the individually simulated electric field. Computational modeling revealed that 20 and 70 Hz stimulation had opposite effects on the braking process. These results highlight that the effects of tACS are state-dependent and demonstrate that fronto-central beta activity is causally related to successful motor inhibition, supporting its use as a functional biomarker.