Metal homeostasis and resistance in bacteria

Overview

This Nature Reviews Microbiology article by Chandrangsu (Cornell), Rensing (Chinese Academy of Sciences and Fujian Agriculture and Forestry University), and Helmann (Cornell) is the foundational reference on bacterial metal homeostasis. The review documents the protein-based and RNA-based metal sensors that activate transcriptional responses to metal limitation (importer induction, metal-mobilization pathway activation) and to metal excess (efflux pump activation, metallothionein-like storage, sequestration). The authors describe the stepwise transcriptional response to metal stress, the post-transcriptional regulatory systems that reinforce it, and the host-driven nutritional immunity strategies (Zn and Mn sequestration by calprotectin; Fe sequestration by transferrin and lipocalin) that exploit bacterial metal-limitation pathways to restrict bacterial growth during infection.

Key conclusions

Metal limitation and metal intoxication are evolutionarily ancient bacterial-growth-restriction strategies. The review covers the major bacterial responses to each of the toxicologically relevant metals (Cu, Zn, Fe, Mn, Ni, Co, Cd, Hg, Pb, Cr), with mechanism-level detail for the Bacillus subtilis, E. coli, and Staphylococcus aureus systems that are the principal model organisms. For toxic metals (Cd, Hg, Pb, Cr-VI, As), the focus is on efflux pumps and metal-binding proteins that minimize intracellular metal load. For essential metals (Fe, Zn, Cu, Mn, Ni, Co), the focus is on the import-versus-efflux balance that maintains intracellular concentrations within tolerable bounds.

Implications

• Certification: Background context for why heavy-metal exposure perturbs gut microbiota composition: the perturbation is not random but reflects which taxa carry adequate metal-tolerance machinery. Provides the mechanistic vocabulary for the Yang 2023, Soto-Ocaña 2024, and related microbiome-shifts-on-metal-exposure findings.
• Microbiome: Foundational reference for any metal-microbiome page. Crosswalks to WikiBiome as a metals-and-microbial-physiology entry.
• Courses: Standard teaching reference for the metallobiology of bacteria.

Wiki pages updated on ingest

• Lead
• Cadmium
• Mercury
• Nickel
• Chromium, Hexavalent

Update history

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