75. Harold FM, Van Brunt J (1977) Circulation of H
+ and K
+ across the plasma membrane is not
obligatory for bacterial growth. Science 197:372–373
76. Speelmans G, Poolman B, Abee T, Konings WN (1993) Energy transduction in the thermophilic anaerobic bacterium Clostridium fervidus is exclusively coupled to sodium ions. Proc
Natl Acad Sci U S A 90:7975–7979
77. Swartz TH, Ikewada S, Ishikawa O, Ito M, Krulwich TA (2005) The Mrp system: a giant
among monovalent cation/proton antiporters? Extremophiles 9:345–354
78. Ito M, Morino M, Krulwich TA (2017) Mrp antiporters have important roles in diverse
bacteria and archaea. Front Microbiol 8:2325. https://doi.org/10.3389/fmicb.2017.02325
79. Kajiyama Y, Otagiri M, Sekiguchi J, Kosono S, Kudo T (2007) Complex formation by the
mrpABCDEFG gene products, which constitute a principal Na
+ /H
+ antiporter in Bacillus
subtilis. J Bacteriol 189:7511–7514
80. Morino M, Natsui S, Swartz TH, Krulwich TA, Ito M (2008) Single gene deletions of mrpA to
mrpG and mrpE point mutations affect activity of the Mrp Na
+ /H
+ antiporter of alkaliphilic
Bacillus and formation of hetero-oligomeric Mrp complexes. J Bacteriol 190:4162–4172
81. Aono R, Ito M, Horikoshi K (1992) Instability of the protoplast membrane of facultative
alkaliphilic Bacillus sp. C-125 at alkaline pH values below the pH optimum for growth.
Biochem J 285:99–103
82. Aono R, Ito M, Machida T (1999) Contribution of the cell wall component teichuronopeptide
to pH homeostasis and alkaliphily in the alkaliphile Bacillus lentus C-125. J Bacteriol
181:6600–6606
83. Aono R, Ogino H, Horikoshi K (1992) pH-dependent flagella formation by facultative
alkaliphilic Bacillus sp. C-125. Biosci Biotechnol Biochem 56:48–53
84. Aono R, Ohtani M (1990) Loss of alkalophily in cell-wall-component-defective mutants
derived from alkalophilic Bacillus C-125. Isolation and partial characterization of the mutants.
Biochem J 266:933–936
85. Gilmour r, Messner P, Guffanti AA, Kent R, Scheberl A, Kendrick N, Krulwich TA (2000)
Two-dimensional gel electrophoresis analyses of pH-dependent protein expression in facultatively alkaliphilic Bacillus pseudofirmus OF4 lead to characterization of an S-layer protein
with a role in alkaliphily. J Bacteriol 182:5969–5981
86. Ito M, Hicks DB, Henkin TM, Guffanti AA, Powers B, Zvi L, Uematsu K, Krulwich TA
(2004) MotPS is the stator-force generator for motility of alkaliphilic Bacillus and its homologue is a second functional Mot in Bacillus subtilis. Mol Microbiol 53:1035–1049
87. Terahara N, Kodera N, Uchihashi T, Ando T, Namba K, Minamino T (2017) Na
+ -induced
structural transition of MotPS for stator assembly of the Bacillus flagellar motor. Sci Adv 3:
eaao4119
88. Fujinami S, Terahara N, Lee S, Ito M (2007) Na
+ and flagella-dependent swimming of
alkaliphilic Bacillus pseudofirmus OF4: a basis for poor motility at low pH and enhancement
in viscous media in an “up-motile” variant. Arch Microbiol 187:239
89. Chahine M, Pilote S, Pouliot V, Takami H, Sato C (2004) Role of arginine residues on the S4
segment of the Bacillus halodurans Na
+ channel in voltage-sensing. J Membr Biol 201:9–24
90. Koishi RXH, Ren D, Navarro B, Spiller BW, Shi Q, Clapham DE (2004) A superfamily of
voltage-gated sodium channels in bacteria. J Biol Chem 279:9532–9538
91. Ito M, Xu H, Guffanti AA, Wei Y, Zvi L, Clapham DE, Krulwich TA (2004) The voltagegated Na
+ channel NavBP has a role in motility, chemotaxis, and pH homeostasis of an
alkaliphilic Bacillus. Proc Natl Acad Sci U S A 101:10566–10571
92. Morino M, Suzuki T, Ito M, Krulwich TA (2014) Purification and functional reconstitution of
a seven-subunit mrp-type Na
+ /H
+ antiporter. J Bacteriol 196:28–35
93. Fujinami S, Sato T, Trimmer JS, Spiller BW, Clapham DE, Krulwich TA et al (2007) The
voltage-gated Na
+ channel NaVBP co-localizes with methyl-accepting chemotaxis protein at
cell poles of alkaliphilic Bacillus pseudofirmus OF4. Microbiology 153:4027–4038
Challenges and Adaptations of Life in Alkaline Habitats
125
+ and K
+ across the plasma membrane is not
obligatory for bacterial growth. Science 197:372–373
76. Speelmans G, Poolman B, Abee T, Konings WN (1993) Energy transduction in the thermophilic anaerobic bacterium Clostridium fervidus is exclusively coupled to sodium ions. Proc
Natl Acad Sci U S A 90:7975–7979
77. Swartz TH, Ikewada S, Ishikawa O, Ito M, Krulwich TA (2005) The Mrp system: a giant
among monovalent cation/proton antiporters? Extremophiles 9:345–354
78. Ito M, Morino M, Krulwich TA (2017) Mrp antiporters have important roles in diverse
bacteria and archaea. Front Microbiol 8:2325. https://doi.org/10.3389/fmicb.2017.02325
79. Kajiyama Y, Otagiri M, Sekiguchi J, Kosono S, Kudo T (2007) Complex formation by the
mrpABCDEFG gene products, which constitute a principal Na
+ /H
+ antiporter in Bacillus
subtilis. J Bacteriol 189:7511–7514
80. Morino M, Natsui S, Swartz TH, Krulwich TA, Ito M (2008) Single gene deletions of mrpA to
mrpG and mrpE point mutations affect activity of the Mrp Na
+ /H
+ antiporter of alkaliphilic
Bacillus and formation of hetero-oligomeric Mrp complexes. J Bacteriol 190:4162–4172
81. Aono R, Ito M, Horikoshi K (1992) Instability of the protoplast membrane of facultative
alkaliphilic Bacillus sp. C-125 at alkaline pH values below the pH optimum for growth.
Biochem J 285:99–103
82. Aono R, Ito M, Machida T (1999) Contribution of the cell wall component teichuronopeptide
to pH homeostasis and alkaliphily in the alkaliphile Bacillus lentus C-125. J Bacteriol
181:6600–6606
83. Aono R, Ogino H, Horikoshi K (1992) pH-dependent flagella formation by facultative
alkaliphilic Bacillus sp. C-125. Biosci Biotechnol Biochem 56:48–53
84. Aono R, Ohtani M (1990) Loss of alkalophily in cell-wall-component-defective mutants
derived from alkalophilic Bacillus C-125. Isolation and partial characterization of the mutants.
Biochem J 266:933–936
85. Gilmour r, Messner P, Guffanti AA, Kent R, Scheberl A, Kendrick N, Krulwich TA (2000)
Two-dimensional gel electrophoresis analyses of pH-dependent protein expression in facultatively alkaliphilic Bacillus pseudofirmus OF4 lead to characterization of an S-layer protein
with a role in alkaliphily. J Bacteriol 182:5969–5981
86. Ito M, Hicks DB, Henkin TM, Guffanti AA, Powers B, Zvi L, Uematsu K, Krulwich TA
(2004) MotPS is the stator-force generator for motility of alkaliphilic Bacillus and its homologue is a second functional Mot in Bacillus subtilis. Mol Microbiol 53:1035–1049
87. Terahara N, Kodera N, Uchihashi T, Ando T, Namba K, Minamino T (2017) Na
+ -induced
structural transition of MotPS for stator assembly of the Bacillus flagellar motor. Sci Adv 3:
eaao4119
88. Fujinami S, Terahara N, Lee S, Ito M (2007) Na
+ and flagella-dependent swimming of
alkaliphilic Bacillus pseudofirmus OF4: a basis for poor motility at low pH and enhancement
in viscous media in an “up-motile” variant. Arch Microbiol 187:239
89. Chahine M, Pilote S, Pouliot V, Takami H, Sato C (2004) Role of arginine residues on the S4
segment of the Bacillus halodurans Na
+ channel in voltage-sensing. J Membr Biol 201:9–24
90. Koishi RXH, Ren D, Navarro B, Spiller BW, Shi Q, Clapham DE (2004) A superfamily of
voltage-gated sodium channels in bacteria. J Biol Chem 279:9532–9538
91. Ito M, Xu H, Guffanti AA, Wei Y, Zvi L, Clapham DE, Krulwich TA (2004) The voltagegated Na
+ channel NavBP has a role in motility, chemotaxis, and pH homeostasis of an
alkaliphilic Bacillus. Proc Natl Acad Sci U S A 101:10566–10571
92. Morino M, Suzuki T, Ito M, Krulwich TA (2014) Purification and functional reconstitution of
a seven-subunit mrp-type Na
+ /H
+ antiporter. J Bacteriol 196:28–35
93. Fujinami S, Sato T, Trimmer JS, Spiller BW, Clapham DE, Krulwich TA et al (2007) The
voltage-gated Na
+ channel NaVBP co-localizes with methyl-accepting chemotaxis protein at
cell poles of alkaliphilic Bacillus pseudofirmus OF4. Microbiology 153:4027–4038
Challenges and Adaptations of Life in Alkaline Habitats
125