Methionine-rich domains emerge as facilitators of copper recruitment in detoxification systems.

Copper homeostasis mechanisms are critical for bacterial resistance to copper-induced stress. The multicopper oxidase copper efflux oxidase (CueO) is part of the copper detoxification system in aerobic conditions. CueO contains a methionine-rich (Met-rich) domain believed to interact with copper, but its exact function and the importance of related copper-binding sites remain unclear.

Engineering of a Bacterial Biosensor for the Detection of Chlorate in Food.

Chlorate can contaminate food due to the use of chlorinated water for processing or equipment disinfection. Chronic exposure to chlorate in food and drinking water is a potential health concern. The current methods for detecting chlorate in liquids and foods are expensive and not easily accessible to all laboratories, highlighting an urgent need for a simple and cost-effective method.

Typhimurium uses the Cpx stress response to detect -chlorotaurine and promote the repair of oxidized proteins.

The cell envelope of gram-negative bacteria constitutes the first protective barrier between a cell and its environment. During host infection, the bacterial envelope is subjected to several stresses, including those induced by reactive oxygen species (ROS) and reactive chlorine species (RCS) produced by immune cells. Among RCS, chlorotaurine (ChT), which results from the reaction between hypochlorous acid and taurine, is a powerful and less diffusible oxidant.

Chlorate Contamination in Commercial Growth Media as a Source of Phenotypic Heterogeneity within Bacterial Populations.

Under anaerobic conditions, chlorate is reduced to chlorite, a cytotoxic compound that triggers oxidative stress within bacterial cultures. We previously found that BD Bacto Casamino Acids were contaminated with chlorate. In this study, we investigated whether chlorate contamination is detectable in other commercial culture media.

Methionine oxidation in bacteria: A reversible post-translational modification.

Methionine is a sulfur-containing residue found in most proteins which are particularly susceptible to oxidation. Although methionine oxidation causes protein damage, it can in some cases activate protein function. Enzymatic systems reducing oxidized methionine have evolved in most bacterial species and methionine oxidation proves to be a reversible post-translational modification regulating protein activity.

Methionine oxidation under anaerobic conditions in Escherichia coli.

Repairing oxidative-targeted macromolecules is a central mechanism necessary for living organisms to adapt to oxidative stress. Reactive oxygen and chlorine species preferentially oxidize sulfur-containing amino acids in proteins. Among these amino acids, methionine can be converted into methionine sulfoxide.

Periplasmic oxidized-protein repair during copper stress in E. coli: A focus on the metallochaperone CusF.

Methionine residues are particularly sensitive to oxidation by reactive oxygen or chlorine species (ROS/RCS), leading to the appearance of methionine sulfoxide in proteins. This post-translational oxidation can be reversed by omnipresent protein repair pathways involving methionine sulfoxide reductases (Msr). In the periplasm of Escherichia coli, the enzymatic system MsrPQ, whose expression is triggered by the RCS, controls the redox status of methionine residues.

HprSR Is a Reactive Chlorine Species-Sensing, Two-Component System in Escherichia coli.

Two-component systems (TCS) are signaling pathways that allow bacterial cells to sense, respond to, and adapt to fluctuating environments. Among the classical TCS of Escherichia coli, HprSR has recently been shown to be involved in the regulation of , which encodes the periplasmic methionine sulfoxide reductase system. In this study, we demonstrated that hypochlorous acid (HOCl) induces the expression of in an HprSR-dependent manner, whereas HO, NO, and paraquat (a superoxide generator) do not.

Methionine Redox Homeostasis in Protein Quality Control.

Bacteria live in different environments and are subject to a wide variety of fluctuating conditions. During evolution, they acquired sophisticated systems dedicated to maintaining protein structure and function, especially during oxidative stress. Under such conditions, methionine residues are converted into methionine sulfoxide (Met-O) which can alter protein function.

Bacterial Genetic Approach to the Study of Reactive Oxygen Species Production in During Infection.

Over the last decade, an increasing number of reports presented larvae as an important model to study host-pathogen interactions. Coherently, increasing information became available about molecular mechanisms used by this host to cope with microbial infections but few of them dealt with oxidative stress. In this work, we addressed the role of reactive oxygen species (ROS) produced by the immune system of to resist against , an intracellular pathogen responsible for a wide range of infections.

Redox controls RecA protein activity via reversible oxidation of its methionine residues.

Reactive oxygen species (ROS) cause damage to DNA and proteins. Here, we report that the RecA recombinase is itself oxidized by ROS. Genetic and biochemical analyses revealed that oxidation of RecA altered its DNA repair and DNA recombination activities.

Characterisation of the periplasmic methionine sulfoxide reductase (MsrP) from Salmonella Typhimurium.

The oxidation of free methionine (Met) and Met residues inside proteins leads to the formation of methionine sulfoxide (Met-O). The reduction of Met-O to Met is catalysed by a ubiquitous enzyme family: the methionine sulfoxide reductases (Msr). The importance of Msr systems in bacterial physiology and virulence has been reported in many species.

Complete Genome Sequence of Escherichia coli BE104, an MC4100 Derivative Lacking the Methionine Reductive Pathway.

In this announcement, we present the complete annotated genome sequence of an MC4100 mutant strain, BE104. This strain has several methionine sulfoxide reductase gene deletions, making it ideal for studying enzymes that alter the redox state of methionine.

[The greater wax moth, Galleria mellonella to study host-pathogen interactions].

The massive use of antibiotics in health and agriculture has led to the emergence of pathogenic microorganisms resistant to frequently used treatments. In 2017, the World Health Organization (WHO) published its first ever list of antibiotic-resistant "priority pathogens", a catalogue of twelve families of bacteria that pose the greatest threat to human health. In this context, a new model for the study of host-pathogen interactions is becoming increasingly popular : the greater wax moth, Galleria mellonella.

Silver and Antibiotic, New Facts to an Old Story.

The therapeutic arsenal against bacterial infections is rapidly shrinking, as drug resistance spreads and pharmaceutical industry are struggling to produce new antibiotics. In this review we cover the efficacy of silver as an antibacterial agent. In particular we recall experimental evidences pointing to the multiple targets of silver, including DNA, proteins and small molecules, and we review the arguments for and against the hypothesis that silver acts by enhancing oxidative stress.

Species-specific activity of antibacterial drug combinations.

The spread of antimicrobial resistance has become a serious public health concern, making once-treatable diseases deadly again and undermining the achievements of modern medicine. Drug combinations can help to fight multi-drug-resistant bacterial infections, yet they are largely unexplored and rarely used in clinics. Here we profile almost 3,000 dose-resolved combinations of antibiotics, human-targeted drugs and food additives in six strains from three Gram-negative pathogens-Escherichia coli, Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa-to identify general principles for antibacterial drug combinations and understand their potential.

Oxidative stress, protein damage and repair in bacteria.

Oxidative damage can have a devastating effect on the structure and activity of proteins, and may even lead to cell death. The sulfur-containing amino acids cysteine and methionine are particularly susceptible to reactive oxygen species (ROS) and reactive chlorine species (RCS), which can damage proteins. In this Review, we discuss our current understanding of the reducing systems that enable bacteria to repair oxidatively damaged cysteine and methionine residues in the cytoplasm and in the bacterial cell envelope.

Silver potentiates aminoglycoside toxicity by enhancing their uptake.

The predicted shortage in new antibiotics has prompted research for chemicals that could act as adjuvant and enhance efficacy of available antibiotics. In this study, we tested the effects of combining metals with aminoglycosides on Escherichia coli survival. The best synergizing combination resulted from mixing aminoglycosides with silver.

The 'liaisons dangereuses' between iron and antibiotics.

The decline in the rate of new antibiotic discovery is of growing concern, and new antibacterial strategies must now be explored. This review brings together research in two fields (metals in biology and antibiotics) in the hope that collaboration between scientists working in these two areas will lead to major advances in understanding and the development of new approaches to tackling microbial pathogens. Metals have been used as antiseptics for centuries.

Repairing oxidized proteins in the bacterial envelope using respiratory chain electrons.

The reactive species of oxygen and chlorine damage cellular components, potentially leading to cell death. In proteins, the sulfur-containing amino acid methionine is converted to methionine sulfoxide, which can cause a loss of biological activity. To rescue proteins with methionine sulfoxide residues, living cells express methionine sulfoxide reductases (Msrs) in most subcellular compartments, including the cytosol, mitochondria and chloroplasts.

Commercial Lysogeny Broth culture media and oxidative stress: a cautious tale.

Lysogeny Broth (LB), most often misnamed Luria-Bertani medium, ranks among the most commonly used growth media in microbiology. Surprisingly, we observed that oxidative levels vary with the commercial origin of the LB ready to use powder. Indeed, growth on solid media of Escherichia coli and Salmonella derivatives lacking antioxidative stress defenses, such as oxyR mutant devoid of the H2O2-sensing transcriptional activator or Hpx(-) strains lacking catalases and peroxidases, exhibit different phenotypes on LB-Sigma or LB-Difco.

Fe-S cluster biosynthesis controls uptake of aminoglycosides in a ROS-less death pathway.

All bactericidal antibiotics were recently proposed to kill by inducing reactive oxygen species (ROS) production, causing destabilization of iron-sulfur (Fe-S) clusters and generating Fenton chemistry. We find that the ROS response is dispensable upon treatment with bactericidal antibiotics. Furthermore, we demonstrate that Fe-S clusters are required for killing only by aminoglycosides.

Reprint of: Iron/sulfur proteins biogenesis in prokaryotes: formation, regulation and diversity.

Iron/sulfur centers are key cofactors of proteins intervening in multiple conserved cellular processes, such as gene expression, DNA repair, RNA modification, central metabolism and respiration. Mechanisms allowing Fe/S centers to be assembled, and inserted into polypeptides have attracted much attention in the last decade, both in eukaryotes and prokaryotes. Basic principles and recent advances in our understanding of the prokaryotic Fe/S biogenesis ISC and SUF systems are reviewed in the present communication.

Iron/sulfur proteins biogenesis in prokaryotes: formation, regulation and diversity.

Iron/sulfur centers are key cofactors of proteins intervening in multiple conserved cellular processes, such as gene expression, DNA repair, RNA modification, central metabolism and respiration. Mechanisms allowing Fe/S centers to be assembled, and inserted into polypeptides have attracted much attention in the last decade, both in eukaryotes and prokaryotes. Basic principles and recent advances in our understanding of the prokaryotic Fe/S biogenesis ISC and SUF systems are reviewed in the present communication.