The enigmatic physiological roles of AhpCF, Gpx, Npr and Kat in peroxide stress response of Enterococcus faecium

Wasselin, Valentin; Budin-Verneuil, Aurélie; Rincé, Isabelle; L, Leger; Boukerb, Amine M.; Hartke, Axel; Benachour, Abdellah; Riboulet-Bisson, Eliette

doi:10.1016/j.resmic.2022.103982

Cited by 4 publications

(5 citation statements)

References 34 publications

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“…In that study, it was demonstrated that npr -defective mutants contain inactive catalase protein. The reason for this enzyme defect remains enigmatic, but presumably the catalase is inactivated by the high cytoplasmic concentrations of H 2 O 2 that result from the lack of NADH peroxidase activity [ 25 ] (Baureder and Hederstedt, unpublished data). Important for the present work, the colonies of E. faecalis strains without catalase protein (EMB1 and EMB17) showed the same pattern of colony ferric reductase zymogram staining as the parental strain on plates both with and without hemin ( Figure 1 ) ( Table 1 ).…”

Section: Resultsmentioning

confidence: 99%

“…Large amounts (≤0.6 mM) of H 2 O 2 can be found in the liquid culture supernatant after the growth of E. faecalis strains and related lactic acid bacteria, for example, Lactobacillus casei , if the cells are grown with glycerol and especially if NADH peroxidase is deficient [ 24 , 25 , 28 , 29 ]. Under aerobic conditions, glycerol can be metabolized in E. faecalis via two pathways: dependent on an NAD-dependent glycerol dehydrogenase and a glycerol kinase, respectively, that catalyzes the first step in the pathway.…”

Section: Resultsmentioning

confidence: 99%

“…The chemistry is complex and depends on the conditions, including the pH and how the iron ion is coordinated [ 32 ]. In E. faecalis , H 2 O 2 is mainly degraded by NADH peroxidase and also when heme is available by catalase, but other peroxidases also contribute [ 24 , 25 , 35 ]. Consequently, in E. faecalis , several enzyme activities combined determine the amount of H 2 O 2 that accumulates in the cytoplasm and on the outside of the cell ( Figure 4 ).…”

Section: Discussionmentioning

confidence: 99%

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Enterococcus faecalis NADH Peroxidase-Defective Mutants Stain Falsely in Colony Zymogram Assay for Extracellular Electron Transfer to Ferric Ions

Hederstedt

2022

Microorganisms

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Enterococcus faecalis cells can reduce ferric ions and other electron acceptors by extracellular electron transfer (EET). To find mutants with enhanced or defective EET, strain OG1RF with random transposon insertions in the chromosome was screened for ferric reductase activity by colony zymogram staining using the chromogenic ferrous-chelating compound Ferrozine. The screen revealed npr, eetB, and ndh3 mutants. The aberrant ferric reductase phenotype of Npr (NADH peroxidase)-defective mutants was found to be a property of colonies and not apparent with washed cells grown in liquid culture. EetB- and Ndh3-defective mutants, in contrast, consistently showed low ferric reductase activity. It is concluded that colony zymogram staining for ferric reductase activity using Ferrozine can be misleading, especially through false negative results. It is suggested that hydrogen peroxide produced in the colony quenches the zymogram staining. In addition, it is demonstrated that the negative effect of heme on EET to ferric ion in E. faecalis is relieved by cytochrome bd deficiency. The findings can help to identify bacteria with EET ability and contribute to our understanding of EET in Gram-positive bacteria and the physiology of E. faecalis.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Enterococcus faecalis NADH Peroxidase-Defective Mutants Stain Falsely in Colony Zymogram Assay for Extracellular Electron Transfer to Ferric Ions

Hederstedt

2022

Microorganisms

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“…Most peroxiredoxins, which are cysteine-dependent peroxidases, use the Trx systems as electron donor (Hanschmann et al, 2013). Peroxiredoxins notably include the alkyl hydroxyperoxide, AhpC (Wasselin et al, 2022), the thiol-peroxidase, Tpx (Comtois, 2003), and the bacterioferritin comigratory protein, Bcp (Reeves et al, 2011). Glutathione peroxidase (Gpx) is another family of peroxiredoxins (Margis et al, 2008).…”

Section: The Direct and Indirect Roles Of Trx Systems In Stress-responsementioning

confidence: 99%

From ubiquity to specificity: The diverse functions of bacterial thioredoxin systems

Anjou,

Lotoux,

Morvan

et al. 2024

Environmental Microbiology

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The thioredoxin (Trx) system, found universally, is responsible for the regeneration of reversibly oxidized protein thiols in living cells. This system is made up of a Trx and a Trx reductase, and it plays a central role in maintaining thiol‐based redox homeostasis by reducing oxidized protein thiols, such as disulfide bonds in proteins. Some Trxs also possess a chaperone function that is independent of thiol‐disulfide exchange, in addition to their thiol‐disulfide reductase activity. These two activities of the Trx system are involved in numerous physiological processes in bacteria. This review describes the diverse physiological roles of the Trx system that have emerged throughout bacterial evolution. The Trx system is essential for responding to oxidative and nitrosative stress. Beyond this primary function, the Trx system also participates in redox regulation and signal transduction, and in controlling metabolism, motility, biofilm formation, and virulence. This range of functions has evolved alongside the diversity of bacterial lifestyles and their specific constraints. This evolution can be characterized by the multiplication of the systems and by the specialization of cofactors or targets to adapt to the constraints of atypical lifestyles, such as photosynthesis, insect endosymbiosis, or spore‐forming bacteria.

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“…NADH-peroxidase ( Npr ), alkyl hydroperoxide reductases ( Ahp ) and thiol peroxidases ( Tpx ) are three peroxidases responsible for reducing reactive oxygen species-mediated bacteriolytic activity of phagocytes among E. faecalis [ 50 ]. Interestingly, the roles of Npr, Ahp and gpx (a putative glutathione peroxidase) in E. faecium do not have a protective role against H 2 O 2 [ 64 ]. Pilli also present virulence factors involved in biofilm formation, cell–cell aggregation and gene transfer, contributing to the pathogenesis of urinary infections and endocarditis and are present in both E. faecium and E. faecalis [ 50 , 65 ].…”

Section: Introductionmentioning

confidence: 99%

Promiscuous, persistent and problematic: insights into current enterococcal genomics to guide therapeutic strategy

Hourigan,

Stefanovic,

Hill

et al. 2024

BMC Microbiol

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Vancomycin-resistant enterococci (VRE) are major opportunistic pathogens and the causative agents of serious diseases, such as urinary tract infections and endocarditis. VRE strains mainly include species of Enterococcus faecium and E. faecalis which can colonise the gastrointestinal tract (GIT) of patients and, following growth and persistence in the gut, can transfer to blood resulting in systemic dissemination in the body. Advancements in genomics have revealed that hospital-associated VRE strains are characterised by increased numbers of mobile genetic elements, higher numbers of antibiotic resistance genes and often lack active CRISPR-Cas systems. Additionally, comparative genomics have increased our understanding of dissemination routes among patients and healthcare workers. Since the efficiency of currently available antibiotics is rapidly declining, new measures to control infection and dissemination of these persistent pathogens are urgently needed. These approaches include combinatory administration of antibiotics, strengthening colonisation resistance of the gut microbiota to reduce VRE proliferation through commensals or probiotic bacteria, or switching to non-antibiotic bacterial killers, such as bacteriophages or bacteriocins. In this review, we discuss the current knowledge of the genomics of VRE isolates and state-of-the-art therapeutic advances against VRE infections.

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The enigmatic physiological roles of AhpCF, Gpx, Npr and Kat in peroxide stress response of Enterococcus faecium

Cited by 4 publications

References 34 publications

Enterococcus faecalis NADH Peroxidase-Defective Mutants Stain Falsely in Colony Zymogram Assay for Extracellular Electron Transfer to Ferric Ions

Enterococcus faecalis NADH Peroxidase-Defective Mutants Stain Falsely in Colony Zymogram Assay for Extracellular Electron Transfer to Ferric Ions

From ubiquity to specificity: The diverse functions of bacterial thioredoxin systems

Promiscuous, persistent and problematic: insights into current enterococcal genomics to guide therapeutic strategy

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