Minimal cobalt metabolism in the marine cyanobacterium Prochlorococcus.
Nicholas J HawcoMatthew M McIlvinRandelle M BundyAlessandro TagliabueTyler J GoepfertDawn M MoranLuis Valentin-AlvaradoGiacomo R DiTullioMak A SaitoPublished in: Proceedings of the National Academy of Sciences of the United States of America (2020)
Despite very low concentrations of cobalt in marine waters, cyanobacteria in the genus Prochlorococcus retain the genetic machinery for the synthesis and use of cobalt-bearing cofactors (cobalamins) in their genomes. We explore cobalt metabolism in a Prochlorococcus isolate from the equatorial Pacific Ocean (strain MIT9215) through a series of growth experiments under iron- and cobalt-limiting conditions. Metal uptake rates, quantitative proteomic measurements of cobalamin-dependent enzymes, and theoretical calculations all indicate that Prochlorococcus MIT9215 can sustain growth with less than 50 cobalt atoms per cell, ∼100-fold lower than minimum iron requirements for these cells (∼5,100 atoms per cell). Quantitative descriptions of Prochlorococcus cobalt limitation are used to interpret the cobalt distribution in the equatorial Pacific Ocean, where surface concentrations are among the lowest measured globally but Prochlorococcus biomass is high. A low minimum cobalt quota ensures that other nutrients, notably iron, will be exhausted before cobalt can be fully depleted, helping to explain the persistence of cobalt-dependent metabolism in marine cyanobacteria.
Keyphrases
- reduced graphene oxide
- carbon nanotubes
- metal organic framework
- single cell
- stem cells
- gold nanoparticles
- cell therapy
- cell death
- cell proliferation
- bone marrow
- genome wide
- induced apoptosis
- risk assessment
- heavy metals
- mass spectrometry
- dna methylation
- density functional theory
- mesenchymal stem cells
- iron deficiency
- anaerobic digestion