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Summary: Gene expression is tightly controlled by transcription factors and RNA regulatory elements, including trans‐acting small RNAs, cis‐regulatory riboswitches and ribosome‐dependent ribo‐regulators. In the present study, we demonstrated that a ribosome‐dependent ribo‐regulator and two mistranslation products co‐regulate rppA (encoding a ribosomal protection protein) expression in Bacillus thuringiensis BMB171. The leader RNA of the rppA gene controls rppA expression via translation of leader ORF1 resident in its sequence. In the presence of chloramphenicol, a +1 frameshift product (ORF2) and a stop codon readthrough product (ORF3) of ORF1 emerged. ORF3 exerted a negative effect on rppA expression. By contrast, the ORF2 promoted rppA expression. The regulation mode identified in the present study will lead to a deeper understanding of bacterial gene expression. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) have recently emerged as antibacterial agents and have attracted considerable attention owing to their fascinating merits of small size, facile fabrication, and surface functionalization. Most of them are involved in external light activation or hybridization with other functional nanomaterials. Herein, we present peroxidase-like Cu-doped CDs (Cu-CDs) for in vitro antibacterial applications. The unique peroxidase-mimicking property of the Cu-CDs was demonstrated by tetramethylbenzidine chromogenic assay, electron paramagnetic resonance spectra, and hydroxy radical probe. Escherichia coli and Staphylococcus aureus were chosen as representative gram-negative/positive models against which Cu-CDs exhibited superior antimicrobial activity even at a dosage down to 5 μg/mL. A possible mechanism of action was that the Cu-CDs triggered a catalytic redox reaction of endogenous H 2 O 2 and glutathione depletion in the bacteria cells, with subsequent oxidative stress and membrane disruption. This work provides a new strategy for the design of microenvironment-responsive antimicrobial nano-agents., (© 2022 Wiley-VCH GmbH.)