pH delta

Edge evidence

• pH-homeostasis flexibility enables pH tolerance breadth RO:0002327

  pH-homeostasis flexibility enables broad pH tolerance.

  • DOI:10.1038/nrmicro2549 pH homeostasis Supports the breadth of pH homeostasis as the basis of broad pH tolerance.
• pH tolerance breadth manifests as pH delta METPO:2007400

  The breadth between minimum and maximum growth-supporting external pH manifests the pH-delta phenotype.

  • DOI:10.1016/j.tim.2007.02.005 proton motive force Supports the bounded proton motive force as the determinant of the pH tolerance breadth.
• external pH homeostasis enables pH delta RO:0002327

  External pH homeostasis enables a broader external pH growth breadth.

  • DOI:10.1093/femsre/fuad033 Na+/H+ and K+/H+ antiporters and proton-pumping systems prevent internal pH from becoming too low, underpinning growth across pH (general bacteria, review).
• proton motive force generation supports external pH homeostasis

  Proton motive force generation supports external pH homeostasis.

  • DOI:10.1093/femsre/fuad033 PMF-linked systems regulate internal pH; decarboxylation can store free energy as PMF (general bacteria, review).
• F0F1-ATPase activity supports external pH homeostasis

  F0F1-ATPase activity supports external pH homeostasis.

  • DOI:10.1093/femsre/fuad033 F0F1-ATPase uses 3-5 protons per ATP and is among systems that prevent internal pH from becoming too low (general bacteria, review).
• monovalent cation:H+ antiporter activity supports external pH homeostasis

  Monovalent cation:H+ antiporter activity supports pH homeostasis under alkaline conditions.

  • DOI:10.1128/AEM.00569-24 Monovalent antiporters exchange Na+/K+ to facilitate proton entry for alkali tolerance (generic transporter class).
• saturated membrane fatty acid remodeling decreases membrane proton permeability RO:0002212

  Saturated membrane fatty acid remodeling decreases membrane proton permeability.

  • DOI:10.3389/fmicb.2022.1034164 Membranes enriched in saturated fatty acids reduce proton permeability, minimizing proton influx in acidic environments (generalizable low-pH mechanism).
• amino-acid decarboxylase acid-resistance system increases low-pH tolerance RO:0002213

  Amino-acid decarboxylase acid-resistance systems increase low-pH tolerance.

  • DOI:10.3390/microorganisms12091774 Amino-acid decarboxylase systems consume protons and export corresponding amines as a key acid-resistance mechanism (authoritative review).
• oxidative phosphorylation supports external pH homeostasis

  Oxidative phosphorylation upregulation supports proton export and resistance to cytoplasmic acidification.

  • DOI:10.3390/microorganisms12081565 Increased oxidative phosphorylation generates PMF and a higher proton export rate, causally helping cells resist decreases in cytoplasmic pH.