Extracellular vesicles as an alternative copper-secretion mechanism in bacteria

• DOI: 10.1016/j.jhazmat.2022.128594
• Publication Date: 2022-02-26T07:30:06Z
• Authors: Steeve Lima; Jorge Matinha-Car...; Joaquín Giner-Lamia; Narciso Couto; Catarina C. Pacheco; Francisco J. Flor...; Phillip C. Wright; Paula Tamagnini; Paulo Oliveira
• Keywords: Synechocystis; Copper toxicity; Efflux

Metal homeostasis is fundamental for optimal performance of cell metabolic pathways. Over the course evolution, several systems emerged to warrant an intracellular metal equilibrium. When exposed growth-challenging copper concentrations, Gram-negative bacteria quickly activate copper-detoxification mechanisms, dependent on transmembrane-protein complexes and metallochaperones that mediate efflux. Here, we show vesiculation also a common bacterial response mechanism high extracellular vesicles (EVs) play role in transporting copper. We present evidence from different ecological niches release copious amounts EVs when Along with activation classical detoxification systems, demonstrate copper-stressed cells cyanobacterium Synechocystis sp. PCC6803 loaded copper-binding metallochaperone CopM. Under standard growth conditions, CopM-loaded could be isolated strain lacking functional TolC-protein, which characterize here as exhibiting copper-sensitive phenotype. Analyses tolC-mutant's cultivated under conditions indicated presence therein, significantly higher levels compared those wild-type. Altogether, these results suggest represent novel copper-secretion mechanism, shedding light into alternative mechanisms resistance.