Frontiers in Microbiology (Oct 2019)

Marine Archaeon Methanosarcina acetivorans Enhances Polyphosphate Metabolism Under Persistent Cadmium Stress

  • Ricardo Jasso-Chávez,
  • Elizabeth Lira-Silva,
  • Kasia González-Sánchez,
  • Violeta Larios-Serrato,
  • Diana Lucía Mendoza-Monzoy,
  • Fernando Pérez-Villatoro,
  • Fernando Pérez-Villatoro,
  • Enrique Morett,
  • Enrique Morett,
  • Alicia Vega-Segura,
  • M. Eugenia Torres-Márquez,
  • Armando Zepeda-Rodríguez,
  • Rafael Moreno-Sánchez

DOI
https://doi.org/10.3389/fmicb.2019.02432
Journal volume & issue
Vol. 10

Abstract

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Phosphate metabolism was studied to determine whether polyphosphate (polyP) pools play a role in the enhanced resistance against Cd2+ and metal-removal capacity of Cd2+-preadapted (CdPA) Methanosarcina acetivorans. Polyphosphate kinase (PPK), exopolyphosphatase (PPX) and phosphate transporter transcript levels and their activities increased in CdPA cells compared to control (Cnt) cells. K+ inhibited recombinant Ma-PPK and activated Ma-PPX, whereas divalent cations activated both enzymes. Metal-binding polyP and thiol-containing molecule contents, Cd2+-removal, and biofilm synthesis were significantly higher in CdPA cells >Cnt cells plus a single addition of Cd2+>Cnt cells. Also, CdPA cells showed a higher number of cadmium, sulfur, and phosphorus enriched-acidocalcisomes than control cells. Biochemical and physiological phenotype exhibited by CdPA cells returned to that of Cnt cells when cultured without Cd2+. Furthermore, no differences in the sequenced genomes upstream and downstream of the genes involved in Cd2+ resistance were found between CdPA and Cnt cells, suggesting phenotype loss rather than genome mutations induced by chronic Cd2+-exposure. Instead, a metabolic adaptation induced by Cd2+ stress was apparent. The dynamic ability of M. acetivorans to change its metabolism, depending on the environmental conditions, may be advantageous to remove cadmium in nature and biodigesters.

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