cardiolipin restricts these H
+ within the microenvironment of the patch creating high
pmf. The presence of cytochrome c such as cytochrome c-550 with high electron
retention capacity significantly enhance the pmf. Moreover, due to the possible
interaction of cardiolipin to the respiratory complexes and ATP synthase, it can to
may continuously shuttle H
+ to the synthase, which may be one of the reasons why
alkaliphiles ATP synthesis is more efficient and strictly H
+
-coupled. Another contribution to high pH adaptation comes from unsaturated bonds of lipids. Double
bonds are known to react with radicals such as OH
À faster than single bonds. Thus,
the double bonds in squalene, squalene derivatives, and unsaturated fatty acids
within the lipid bilayer scavenge OH
À traversing the membrane. Although it needs
to be experimentally supported, desaturases probably re-establish the double bonds
lost by reacting with ingressing OH
À .
It is very clear that our understanding of high pH adaptation is expanding due to
the trickling information. However, the studies are still focused on prokaryotes.
Even among prokaryotes, with very few exceptions, almost all the studies are
directed to Gram-positive bacteria. On the other hand, there are largely diverse
Gram-negative bacteria, archaea, and eukaryotes that are known thriving in high
pH habitats. It could be interesting to include these groups of organisms in future
studies.
References
1. Jones BE, Grant WD, Duckworth AW, Owenson GG (1998) Microbial diversity of soda lakes.
Extremophiles 2:3191–3200
2. Sorokin DY, Berben T, Melton EM, Overmars L, Vavourakis CD, Muyzer G (2014) Microbial
diversity and biogeochemical cycling in soda lakes. Extremophiles 18:791–809
3. Borsodi AK, Korponai K, Schumann P, Spröer C, Felföldi T, Márialigeti K, Szili-Kovács T,
Tóth E (2017) Nitrincola alkalilacustris sp. nov. and Nitrincola schmidtii sp. nov., alkaliphilic
bacteria isolated from soda pans, and emended description of the genus Nitrincola. Int J Syst
Evol Microbiol 67:5159–5164
4. Olivera N, Siňeriz F, Breccia JD (2005) Bacillus patagoniensis sp. nov., a novel alkalitolerant
bacterium from Atriplex lampa rhizosphere, Patagonia, Argentina. Int J Syst Evol Microbiol
55:443–447
5. Szabo A, Korponai K, erepesi Cs K, Somogyi B, Vörös L, Bartha D et al (2017) Soda pans of
the Pannonian steppe harbor unique bacterial communities adapted to multiple extreme
conditions. Extremophiles 21:639–649
6. Zhang G, Yang Y, Wang S, Sun Z, Jiao K (2015) Alkalimicrobium pacificum gen. nov.,
sp. nov., a marine bacterium in the family Rhodobacteraceae. Int J Syst Evol Microbiol
65:2453–2458
7. Zhang YG, Lu XH, Ding YB, Wang SJ, Zhou XK, Wang HF et al (2016) Lipingzhangella
halophila gen. nov., sp. nov., a new member of the family Nocardiopsaceae. Int J Syst Evol
Microbiol 66:4071–4076
8. Ohkuma M, Shimizu H, Thongaram T, Kosono S, Moriya K, Trakulnaleam S et al (2003) An
alkaliphilic and xylanolytic Paenibacillus species isolated from the gut of a soil-feeding
termite. Microbes Environ 18:145–151
Challenges and Adaptations of Life in Alkaline Habitats
121
+ within the microenvironment of the patch creating high
pmf. The presence of cytochrome c such as cytochrome c-550 with high electron
retention capacity significantly enhance the pmf. Moreover, due to the possible
interaction of cardiolipin to the respiratory complexes and ATP synthase, it can to
may continuously shuttle H
+ to the synthase, which may be one of the reasons why
alkaliphiles ATP synthesis is more efficient and strictly H
+
-coupled. Another contribution to high pH adaptation comes from unsaturated bonds of lipids. Double
bonds are known to react with radicals such as OH
À faster than single bonds. Thus,
the double bonds in squalene, squalene derivatives, and unsaturated fatty acids
within the lipid bilayer scavenge OH
À traversing the membrane. Although it needs
to be experimentally supported, desaturases probably re-establish the double bonds
lost by reacting with ingressing OH
À .
It is very clear that our understanding of high pH adaptation is expanding due to
the trickling information. However, the studies are still focused on prokaryotes.
Even among prokaryotes, with very few exceptions, almost all the studies are
directed to Gram-positive bacteria. On the other hand, there are largely diverse
Gram-negative bacteria, archaea, and eukaryotes that are known thriving in high
pH habitats. It could be interesting to include these groups of organisms in future
studies.
References
1. Jones BE, Grant WD, Duckworth AW, Owenson GG (1998) Microbial diversity of soda lakes.
Extremophiles 2:3191–3200
2. Sorokin DY, Berben T, Melton EM, Overmars L, Vavourakis CD, Muyzer G (2014) Microbial
diversity and biogeochemical cycling in soda lakes. Extremophiles 18:791–809
3. Borsodi AK, Korponai K, Schumann P, Spröer C, Felföldi T, Márialigeti K, Szili-Kovács T,
Tóth E (2017) Nitrincola alkalilacustris sp. nov. and Nitrincola schmidtii sp. nov., alkaliphilic
bacteria isolated from soda pans, and emended description of the genus Nitrincola. Int J Syst
Evol Microbiol 67:5159–5164
4. Olivera N, Siňeriz F, Breccia JD (2005) Bacillus patagoniensis sp. nov., a novel alkalitolerant
bacterium from Atriplex lampa rhizosphere, Patagonia, Argentina. Int J Syst Evol Microbiol
55:443–447
5. Szabo A, Korponai K, erepesi Cs K, Somogyi B, Vörös L, Bartha D et al (2017) Soda pans of
the Pannonian steppe harbor unique bacterial communities adapted to multiple extreme
conditions. Extremophiles 21:639–649
6. Zhang G, Yang Y, Wang S, Sun Z, Jiao K (2015) Alkalimicrobium pacificum gen. nov.,
sp. nov., a marine bacterium in the family Rhodobacteraceae. Int J Syst Evol Microbiol
65:2453–2458
7. Zhang YG, Lu XH, Ding YB, Wang SJ, Zhou XK, Wang HF et al (2016) Lipingzhangella
halophila gen. nov., sp. nov., a new member of the family Nocardiopsaceae. Int J Syst Evol
Microbiol 66:4071–4076
8. Ohkuma M, Shimizu H, Thongaram T, Kosono S, Moriya K, Trakulnaleam S et al (2003) An
alkaliphilic and xylanolytic Paenibacillus species isolated from the gut of a soil-feeding
termite. Microbes Environ 18:145–151
Challenges and Adaptations of Life in Alkaline Habitats
121