NaCl optimum

Edge evidence

• ambient NaCl concentration causes osmotic balance biolink:causes

  External NaCl level engages the osmoadaptive balance machinery.

  • DOI:10.1186/1746-1448-4-2 cope with the high salt concentrations Supports osmotic balance as the response to ambient NaCl.
• compatible solutes regulates osmotic balance RO:0002211

  Compatible-solute accumulation maintains osmotic balance at the optimal NaCl.

  • DOI:10.1093/femsre/fuy009 synthesize organic osmotic solutes Supports compatible solutes as the osmoadaptive osmolyte.
• Na+/H+ antiporters enables osmotic balance RO:0002327

  Na+/H+ antiporters support ion homeostasis underlying osmotic balance.

  • DOI:10.1093/femsre/fuy009 Na+/H+ antiporters Supports antiporter-driven Na+ extrusion as an osmoadaptive mechanism.
• osmotic balance enables maximal growth rate RO:0002327

  Maintained osmotic balance enables peak growth at the optimal NaCl concentration.

  • DOI:10.1186/1746-1448-4-2 optimum Supports peak growth at the optimal NaCl as the operational definition of NaCl optimum.
• maximal growth rate manifests as NaCl optimum METPO:2007400

  The NaCl concentration at which peak growth is achieved manifests the NaCl-optimum phenotype.

  • DOI:10.1093/femsre/fuy009 optimal NaCl Supports the trait endpoint.
• ambient NaCl concentration induces osmotic stress

  External NaCl concentration imposes osmotic stress that drives osmoadaptation.

  • DOI:10.1186/1746-1448-4-2 Halophilic microorganisms use two strategies to balance their cytoplasm osmotically with their medium (broad review-level mechanism).
• salt-in strategy increases intracellular K+ accumulation RO:0002213

  The salt-in strategy accumulates molar concentrations of KCl in the cytoplasm.

  • DOI:10.1186/1746-1448-4-2 The first involves accumulation of molar concentrations of KCl; strong general mechanism across extreme halophiles.
• acidic proteome enables protein stability at high salt RO:0002327

  An acidic proteome enables protein stability and enzymatic function at high intracellular salt.

  • DOI:10.1186/1746-1448-4-2 The proteome of such organisms is highly acidic; requires adaptation of the intracellular enzymatic machinery at near-saturating salt.
• compatible-solute accumulation regulates osmotic balance RO:0002211

  Accumulation of organic compatible solutes maintains osmotic balance without interfering with enzyme activity.

  • DOI:10.1186/1746-1448-4-2 Exclude salt from the cytoplasm and synthesize/accumulate organic compatible solutes that do not interfere with enzymatic activity; broad canonical mechanism.
• compatible solute uptake associated with lower energetic cost than de novo synthesis biolink:associated_with

  Uptake of compatible solutes from the medium is energetically favored over de novo synthesis.

  • DOI:10.3389/fmicb.2022.846677 Uptake of compatible solute from the medium is preferred over de novo synthesis, reflecting an energetically favored mechanism.
• Na+/H+ antiport activity regulates cytoplasmic Na+ homeostasis RO:0002211

  Na+/H+ antiport activity lowers cytoplasmic Na+ to maintain ion homeostasis and prevent toxicity.

  • DOI:10.1128/aem.00145-24 Na+/H+ antiporters function to lower cytoplasmic Na+ to prevent toxicity and contribute to salt acclimation.