pH range mid3

Edge evidence

• alkaliphile pH homeostasis enables pH range mid3 RO:0002327

  Alkaliphile pH-homeostasis enables growth across pH 8–10.

  • DOI:10.1038/nrmicro2549 alkaliphiles Supports alkaliphile cytoplasmic pH homeostasis as the alkaline growth-range mechanism.
• pH range mid3 is a pH range rdfs:subClassOf

  pH range mid3 is a quantitative bin of the pH-range phenotype.

  • DOI:10.1016/j.tim.2007.02.005 proton motive force Supports the pH 8–10 range as a value within the pH-range distribution.
• Mrp Na+/H+ antiporter complex maintains intracellular pH homeostasis

  Mrp Na+/H+ antiporter complex maintains intracellular pH homeostasis under alkaline stress.

  • DOI:10.1038/s41467-022-33640-y Mrp antiporters essential for growth of alkaliphilic bacteria under stress, maintaining intracellular pH and sodium homeostasis.
• Na+/H+ antiport activity causes cytoplasm acidification during alkaline growth biolink:causes

  Na+/H+ antiport activity acidifies the cytoplasm during alkaline growth.

  • DOI:10.1007/s13205-021-02938-x Alkaliphiles rely on dedicated Na+/H+ antiporters that import H+ in exchange for Na+, acidifying the cytoplasm for pH homeostasis.
• cytoplasm acidification during alkaline growth contributes to intracellular pH homeostasis RO:0002326

  Acidification of the cytoplasm contributes to intracellular pH homeostasis at high external pH.

  • DOI:10.1007/s13205-021-02938-x Proton import via antiport acidifies cytoplasm, a core alkaliphile pH-homeostasis mechanism.
• acidic cell-wall polymers (teichuronic acid) contributes to pH range mid3 RO:0002326

  Acidic cell-wall polymers (teichuronic acid) contribute to alkaline pH tolerance.

  • DOI:10.1007/s13205-021-02938-x Alkaliphilic Bacilli reinforce the cell wall with negatively charged teichuronic acid/acidic polymers, hypothesized to repel OH- and adsorb Na+/H+.
• cardiolipin-rich negatively charged membrane supports intracellular pH homeostasis

  Cardiolipin-rich negatively charged membranes support pH homeostasis at high pH.

  • DOI:10.1007/s13205-021-02938-x Alkaliphiles tend to enrich membranes in negatively charged phospholipids including cardiolipin, noted as especially important for pH homeostasis.
• carbonate-buffered alkaline medium enables observation of pH range mid3

  Carbonate-buffered alkaline medium enables assay/observation of the alkaliphile growth phenotype.

  • DOI:10.1007/s13205-023-03733-6 Alkaliphiles are commonly cultured with sodium carbonate/bicarbonate to set pH around 9.5-10, shaping the measured pH niche.
• observed growth-supporting pH range ~7.5-10.2 is evidence for pH range mid3

  Observed growth across pH ~7.5-10.2 is evidence for the pH range mid3 phenotype.

  • DOI:10.3389/fmicb.2023.1228266 C. thermarum grows pH 7.5-11; alkaliphilic methanogens grow 7.5-10.0 and 7.7-10.2, delimiting the pH 8-10 trait scope.