Magnetotactic bacteria (MTB) represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe 3O 4) or greigite (Fe 3S 4) and cause cells to align along the Earth’s geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic–anoxic interface (OAI) in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes- Verrucomicrobia- Chlamydiae (PVC) bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0.
Amann, R.; Peplies, J.; Schüler, D. Diversity and taxonomy of magnetotactic bacteria. In Magnetoreception and Magnetosomes, in Bacteria; Schüler, D., Ed.; Microbiology Monographs; Springer: Berlin/Heidelberg, Germany, 2007; Volume 3, pp. 25–36.
[5]
Kolinko, S.; Jogler, C.; Katzmann, E.; Wanner, G.; Peplies, J.; Schüler, D. Single-cell analysis reveals a novel uncultivated magnetotactic bacterium within the candidate division OP3. Environ. Microbiol.？2012, 14, 1709–1721, doi:10.1111/j.1462-2920.2011.02609.x. 22003954
[6]
Lefèvre, C.T.; Viloria, N.; Schmidt, M.L.; Pósfai, M.; Frankel, R.B.; Bazylinski, D.A. Novel magnetite-producing magnetotactic bacteria belonging to the Gammaproteobacteria. ISME J.？2012, 6, 440–450, doi:10.1038/ismej.2011.97. 21776027
[7]
Bazylinski, D.A.; Schübbe, S. Controlled biomineralization by and applications of magnetotactic bacteria. Adv. Appl. Microbiol.？2007, 62, 21–62. 17869601
[8]
Schleifer, K.H.; Schüler, D.; Spring, S.; Weizenegger, M.; Amann, R.; Ludwig, W.; Kohler, M. The genus Magnetospirillum gen. nov. description of Magnetospirillum gryphiswaldense sp. nov. and transfer of Aquaspirillum magnetotacticum to Magnetospirillum magnetotacticum comb. nov. Syst. Appl. Microbiol.？1991, 14, 379–385, doi:10.1016/S0723-2020(11)80313-9.
[9]
Sakaguchi, T.; Arakaki, A.; Matsunaga, T. Desulfovibrio magneticus sp nov., a novel sulfate-reducing bacterium that produces intracellular single-domain-sized magnetite particles. Int. J. Syst. Evol. Microbiol.？2002, 52, 215–221. 11837306
[10]
Bazylinski, D.A.; Williams, T.J.; Lefèvre, C.T.; Berg, R.J.; Zhang, C.L.; Bowser, S.S.; Dean, A.J.; Beveridge, T.J. Magnetococcus marinus gen. nov., sp. nov., a marine, magnetotactic bacterium that represents a novel lineage (Magnetococcaceae fam. nov.; Magnetococcales ord. nov.) at the base of the Alphaproteobacteria. Int. J. Syst. Evol. Microbiol.？2013, 63, 801–808, doi:10.1099/ijs.0.038927-0. 22581902
[11]
Williams, T.J.; Lefèvre, C.T.; Zhao, W.; Beveridge, T.J.; Bazylinski, D.A. Magnetospira thiophila gen. nov., sp. nov., a marine magnetotactic bacterium that represents a novel lineage within the Rhodospirillaceae (Alphaproteobacteria). Int. J. Syst. Evol. Microbiol.？2012, 62, 2443–2450, doi:10.1099/ijs.0.037697-0. 22140150
[12]
Bazylinski, D.A.; Williams, T.J.; Lefèvre, C.T.; Trubitsyn, D.; Fang, J.; Beveridge, T.J.; Moskowitz, B.M.; Ward, B.; Schübbe, S.; Dubbels, B.L.; Simpson, B. Magnetovibrio blakemorei, gen. nov. sp. nov., a new magnetotactic bacterium (Alphaproteobacteria: Rhodospirillaceae) isolated from a salt marsh. Int. J. Syst. Evol. Microbiol.？2013, doi:10.1099/ijs.0.037697-0.
[13]
McKay, D.S.; Gibson, E.K.; Thomas-Keprta, K.L.; Vali, H.; Romanek, C.S.; Clemett, S.J.; Chillier, X.D.F.; Maechling, C.R.; Zare, R.N. Search for past life on Mars: Possible relic biogenic activity in Martian meteorite ALH84001. Science？1996, 273, 924–930, doi:10.1126/science.273.5277.924.
Lefèvre, C.T.; Abreu, F.; Schmidt, M.L.; Lins, U.; Frankel, R.B.; Hedlund, B.P.; Bazylinski, D.A. Moderately thermophilic magnetotactic bacteria from hot springs in Nevada. Appl. Environ. Microbiol.？2010, 76, 3740–3743, doi:10.1128/AEM.03018-09. 20382815
[16]
Anderson, J.P. A geochemical study of the southwest part of the Black Rock Desert and its geothermal areas; Washoe, Pershing, and Humboldt Counties, Nevada. Colo. School Mines Q.？1978, 73, 15–22.
[17]
Costa, K.C.; Navarro, J.B.; Shock, E.L.; Zhang, C.L.; Soukup, D.; Hedlund, B.P. Microbiology and geochemistry of great boiling and mud hot springs in the United States Great Basin. Extremophiles？2009, 13, 447–459, doi:10.1007/s00792-009-0230-x.
[18]
Haouari, O.; Fardeau, M.-L.; Cayol, J.-L.; Fauque, G.; Casiot, C.; Elbaz-Poulichet, F.; Hamdi, M.; Ollivier, B. Thermodesulfovibrio hydrogeniphilus sp. nov., a new thermophilic sulphate-reducing bacterium isolated from a Tunisian hot spring. Syst. Appl. Microbiol.？2008, 31, 38–42, doi:10.1016/j.syapm.2007.12.002. 18221850
[19]
Nash, C. Mechanisms and evolution of magnetotactic bacteria. Ph.D. thesis, California Institute of Technology, Pasadena, CA, USA, 2008.
[20]
Lefèvre, C.T.; Frankel, R.B.; Pósfai, M.; Prozorov, T.; Bazylinski, D.A. Isolation of obligately alkaliphilic magnetotactic bacteria from extremely alkaline environments. Environ. Microbiol.？2011, 13, 2342–2350, doi:10.1111/j.1462-2920.2011.02505.x.
[21]
Oremland, R.S.; Dowdle, P.R.; Hoeft, S.; Sharp, J.O.; Schaefer, J.K.; Miller, L.G.; Blum, J.S.; Smith, R.L.; Bloom, N.S.; Wallschlaeger, D. Bacterial dissimilatory reduction of arsenate and sulfate in meromictic Mono Lake, California. Geochim. Cosmochim. Acta.？2000, 64, 3073–3084, doi:10.1016/S0016-7037(00)00422-1.
[22]
Kulp, T.R.; Han, S.; Saltikov, C.W.; Lanoil, B.D.; Zargar, K.; Oremland, R.S. Effects of imposed salinity gradients on dissimilatory arsenate reduction, sulfate reduction, and other microbial processes in sediments from two California soda lakes. Appl. Environ. Microbiol.？2007, 73, 5130–5137, doi:10.1128/AEM.00771-07.
[23]
Hoeft, S.E.; Kulp, T.R.; Stolz, J.F.; Hollibaugh, J.T.; Oremland, R.S. Dissimilatory arsenate reduction with sulfide as electron donor: experiments with mono lake water and isolation of strain MLMS-1, a chemoautotrophic arsenate respirer. Appl. Environ. Microbiol.？2004, 70, 2741–2747, doi:10.1128/AEM.70.5.2741-2747.2004.
[24]
Wiemeyer, S. Metals and trace elements in water, sediment, and vegetation at Ash Meadows National Wildlife Refuge-1993. In Technical Report for the United States Fish and Wildlife Service; Reno, NV, USA, 2005.
[25]
Al-Qudah, O.; Woocay, A.; Walton, J. Identification of probable groundwater paths in the Amargosa Desert vicinity. Appl. Geochem.？2011, 26, 565–574, doi:10.1016/j.apgeochem.2011.01.014.
[26]
Pikuta, E.V.; Hoover, R.B.; Bej, A.K.; Marsic, D.; Whitman, W.B.; Cleland, D.; Krader, P. Desulfonatronum thiodismutans sp. nov., a novel alkaliphilic, sulfate-reducing bacterium capable of lithoautotrophic growth. Int. J. Syst. Evol. Microbiol.？2003, 53, 1327–1332, doi:10.1099/ijs.0.02598-0. 13130014
Chavadar, M.S.; Bajekal, S.S. Microaerophilic magnetotactic bacteria from Lonar Lake, India. J. Pure Appl. Microbiol.？2010, 4, 681–685.
[29]
Rajasekhar, R.P.; Mishra, D.C. Analysis of gravity and magnetic anomalies over Lonar Lake, India: An impact crater in a basalt province. Curr. Sci.？2005, 88, 1836–1840.
[30]
Krulwich, T.A. Alkaliphilic prokaryotes. In The Prokaryotes; Dworkin, M., Falkow, S., Rosenberg, E., Schleifer, K.-H., Stackebrandt, E., Eds.; Springer: New York, NY, USA, 2006; pp. 283–308.
[31]
Jimenez-Lopez, C.; Romanek, C.S.; Bazylinski, D.A. Magnetite as a prokaryotic biomarker: A review. J. Geophys. Res. Biogeosci.？2010, 115, G00G03, doi:10.1029/2009JG001152.
[32]
Schübbe, S.; Kube, M.; Scheffel, A.; Wawer, C.; Heyen, U.; Meyerdierks, A.; Madkour, M.H.; Mayer, F.; Reinhardt, R.; Schüler, D. Characterization of a spontaneous nonmagnetic mutant of Magnetospirillum gryphiswaldense reveals a large deletion comprising a putative magnetosome island. J. Bacteriol.？2003, 185, 5779–5790, doi:10.1128/JB.185.19.5779-5790.2003.
[33]
Dubbels, B.L.; DiSpirito, A.A.; Morton, J.D.; Semrau, J.D.; Neto, J.N.E.; Bazylinski, D.A. Evidence for a copper-dependent iron transport system in the marine, magnetotactic bacterium strain MV-1. Microbiology？2004, 150, 2931–2945, doi:10.1099/mic.0.27233-0.
[34]
Schüler, D. Genetics and cell biology of magnetosome formation in magnetotactic bacteria. FEMS Microbiol. Rev.？2008, 32, 654–672, doi:10.1111/j.1574-6976.2008.00116.x.
[35]
Pósfai, M.; Moskowitz, B.M.; Arató, B.; Schüler, D.; Flies, C.; Bazylinski, D.A.; Frankel, R.B. Properties of intracellular magnetite crystals produced by Desulfovibrio magneticus strain RS-1. Earth Planet Sci. Lett.？2006, 249, 444–455, doi:10.1016/j.epsl.2006.06.036.
[36]
Fang, J.; Zhang, L.; Bazylinski, D.A. Deep-sea piezosphere and piezophiles: geomicrobiology and biogeochemistry. Trends Microbiol.？2010, 18, 413–422, doi:10.1016/j.tim.2010.06.006.
[37]
Stolz, J.; Chang, S.B.R.; Kirschvink, J.L. Magnetotactic bacteria and single-domain magnetite in hemipelagic sediments. Nature？1986, 321, 849–851, doi:10.1038/321849a0.
[38]
Petermann, H.; Bleil, U. Detection of live magnetotactic bacteria in South Atlantic deep-sea sediments. Earth Planet. Sci. Lett.？1993, 117, 223–228, doi:10.1016/0012-821X(93)90128-V.
[39]
Abreu, F.; Lins, U. Universidade Federal do Rio de Janeiro: Rio de Janeiro, Brazil, 2013.
[40]
Baker-Austin, C.; Dopson, M. Life in acid: pH homeostasis in acidophiles. Trends Microbiol.？2007, 15, 165–171, doi:10.1016/j.tim.2007.02.005.
Martins, J.L.; Silveira, T.S.; Silva, K.T.; Lins, U. Salinity dependence of the distribution of multicellular magnetotactic prokaryotes in a hypersaline lagoon. Int. Microbiol.？2009, 12, 193–201. 19784926
[44]
Lefèvre, C.T.; Abreu, F.; Lins, U.; Bazylinski, D.A. Nonmagnetotactic multicellular prokaryotes from low-saline, nonmarine aquatic environments and their unusual negative phototactic behavior. Appl. Environ. Microbiol.？2010, 76, 3220–3227, doi:10.1128/AEM.00408-10.
Thomas-Keprta, K.L.; Clemett, S.J.; Bazylinski, D.A.; Kirschvink, J.L.; McKay, D.S.; Wentworth, S.J.; Vali, H.; Gibson, E.K.; Romanek, C.S. Magnetofossils from ancient Mars: a robust biosignature in the Martian meteorite ALH84001. Appl. Environ. Microbiol.？2002, 68, 3663–3672, doi:10.1128/AEM.68.8.3663-3672.2002.
[48]
Buseck, P.R.; Dunin-Borkowski, R.E.; Devouard, B.; Frankel, R.B.; McCartney, M.R.; Midgley, P.A.; Posfai, M.; Weyland, M. Magnetite morphology and life on Mars. P. Natl. Acad. Sci. USA？2001, 98, 13490–13495, doi:10.1073/pnas.241387898.
Chang, S.B.R.; Kirschvink, J.L. Magnetofossils, the magnetization of sediments, and the evolution of magnetite biomineralization. Annu. Rev. Earth Planet Sci.？1989, 17, 169–195, doi:10.1146/annurev.ea.17.050189.001125.
[51]
Golden, D.C.; Ming, D.W.; Morris, R.V.; Brearley, A.J.; Lauer, H.V., Jr.; Treiman, A.H.; Zolensky, M.E.; Schwandt, C.S.; Lofgren, G.E.; McKay, G.A. Evidence for exclusively inorganic formation of magnetite in Martian meteorite ALH84001. Am. Mineral.？2004, 89, 681–695.
[52]
Martel, J.; Young, D.; Peng, H.-H.; Wu, C.-Y.; Young, J.D. Biomimetic properties of minerals and the search for life in the Martian meteorite ALH84001. Annu. Rev. Earth Planet. Sci.？2012, 40, 167–193, doi:10.1146/annurev-earth-042711-105401.
[53]
Weiss, B.P.; Kim, S.S.; Kirschvink, J.L.; Kopp, R.E.; Sankaran, M.; Kobayashi, A.; Komeili, A. Magnetic tests for magnetosome chains in Martian meteorite ALH84001. P. Natl. Acad. Sci. USA？2004, 101, 8281–8284, doi:10.1073/pnas.0402292101.
[54]
Arato, B.; Szanyi, Z.; Flies, C.; Schüler, D.; Frankel, R.B.; Buseck, P.R.; Pósfai, M. Crystal-size and shape distributions of magnetite from uncultured magnetotactic bacteria as a potential biomarker. Am. Mineral.？2005, 90, 1233–1240, doi:10.2138/am.2005.1778.
[55]
Kopp, R.E.; Kirschvink, J.L. The identification and biogeochemical interpretation of fossil magnetotactic bacteria. Earth Sci. Rev.？2008, 86, 42–61, doi:10.1016/j.earscirev.2007.08.001.
[56]
Gehring, A.U.; Kind, J.; Charilaou, M.; Garcia-Rubio, I. The detection of magnetotactic bacteria and magnetofossils by means of magnetic anisotropy. Earth Planet. Sci. Lett.？2011, 309, 113–117, doi:10.1016/j.epsl.2011.06.024.
[57]
Kind, J.; Gehring, A.U.; Winklhofer, M.; Hirt, A.M. Combined use of magnetometry and spectroscopy for identifying magnetofossils in sediments. Geochem. Geophys. Geosyst.？2011, 12, Q08008.
[58]
Kempe, S.; Degens, E. An early soda ocean? Chem. Geol.？1985, 53, 95–108, doi:10.1016/0009-2541(85)90023-3.
[59]
Hecht, M.H.; Kounaves, S.P.; Quinn, R.C.; West, S.J.; Young, S.M.M.; Ming, D.W.; Catling, D.C.; Clark, B.C.; Boynton, W.V.; Hoffman, J.; et al. Detection of perchlorate and the soluble chemistry of martian soil at the Phoenix lander site. Science？2009, 325, 64–67. 19574385
[60]
Kounaves, S.P.; Hecht, M.H.; Kapit, J.; Gospodinova, K.; DeFlores, L.; Quinn, R.C.; Boynton, W.V.; Clark, B.C.; Catling, D.C.; Hredzak, P.; et al. Wet chemistry experiments on the 2007 Phoenix Mars Scout Lander mission: Data analysis and results. J. Geophys. Res. Planets？2010, 115.
[61]
Kempe, S.; Kazmierczak, J. A terrestrial model for an alkaline martian hydrosphere. Planet Space Sci.？1997, 45, 1493–1499, doi:10.1016/S0032-0633(97)00116-5.
[62]
McNeill, D.F.; Ginsburg, R.N.; Chang, S.B.R.; Kirschvink, J.L. Magnetostratigraphic dating of shallow-water carbonates from San-Salvador, Bahamas. Geology？1988, 16, 8–12, doi:10.1130/0091-7613(1988)016<0008:MDOSWC>2.3.CO;2.
[63]
Sakai, S.; Jige, M. Characterization of magnetic particles and magnetostratigraphic dating of shallow-water carbonates in the Ryukyu Islands, northwestern Pacific. Isl. Arc.？2006, 15, 468–475, doi:10.1111/j.1440-1738.2006.00542.x.
[64]
Bellini, S. On a unique behavior of freshwater bacteria. Chin. J. Oceanol. Limn.？2009, 27, 3–5, doi:10.1007/s00343-009-0003-5.
[65]
Bellini, S. Further studies on “magnetosensitive bacteria”. Chin. J. Oceanol. Limn.？2009, 27, 6–12, doi:10.1007/s00343-009-0006-2.
