Hojatollah Vali

vali [at] eps.mcgill.ca (Email)

Hojatollah ValiInvestigation of process occurring at the interface between inorganic and organic phases leading to the nucleation and growth of crystals (biomineralization) in both natural and synthetic systems. This is achieved through an interdisciplinary approach that integrates mineralogy, morphology, and molecular biology in two distinct areas: (I) pathogenic mineralogization and calcification in mammalian cells and tissues. Current research involves studying both bacteria controlled and protein based mineralization in Fe-oxides, Fe-sulphides, carbonates, hyroxyapapite, and clay minerals. (ii) Investigating biomarkers as signatures of ancient biological activity interrestrial and extraterrestrial materials. This research invloves the investigation of Martian meteorite and terrestrial analog samples. Current research topics related to bacteria-rock interaction and biomineralization processes under harsh conditions, which are relevant to Astrobiology and the Mars Sample Return Missions, are studied in various environments particularly: (a) deep-sea hydrothermal vents, (b) deep subsurface sedimentary basins, and (c) Antarctic and Canadian High Arctic permafrost environments.


Alipour, A., Naderi, G., Bakhshandeh, G.R., Vali, H., & Shokoohi, Sh. (2011) Elastomer nanocomposites based on NR/EPDM/organoclay: morphology and properties. Intern. Polymer Processing, XXVI (in press).

Ariya, P., Domine, F., Kos, G., Amyot, M., Cote, V., Vali, H., Lauzier, T., Kuhs, W., Techmer, K., Heinrichs, T. Mortazavi, R. (2011) Snow - A photobiochemical exchange platform for volatile and semi-volatile organic compounds with the atmosphere. Environmental Chemistry, (in press).

Mahmoudi, M., Vali, H., et al. (2011), Irreversible changes in protein conformation due to interaction with superparamagnetic iron oxide nanoparticles, Nanoscale, (in press).

Moon, J.-W., Rawn, C.J., Rondinone, A.J., Wang, W., Vali, H., Yeary, L.W., Love, L.J.,  Kirkham, M.J.,  Gu, B., & Phelps, T.J. (2010) Crystallite sizes and lattice parameters of nano-biomagnetite particles. J. Nanosci. Nanotechnol., 10, 8298-8306.

Dadash, M.S.,  Nasr Esfahany, M.,  Ebrahimi, R., Karbasi, S. & Vali, H. (2010) A comparative study on mechanical and adhesion properties of calcinated and non calcinated nanobioglass-titania nano composite coatings on stainless steel substrates. Sci. Iran., Trans. F: Nanotech., 17, 66-72.

Lotfabad, T.B., Abassi, H., Ahmadkhaniha, R., Roostaazad, R., Masoomi, F., Zahiri, H.S., Ahmadian, G., Vali, H., & Noghabi, K.A. (2010) Structural characterization of a rhamnolipid-type biosurfactant produced by Pseudomonas aeruginosa MR01: enhancement of di-rhamnolipid proportion using gamma irradiation. Colloids Surfaces. B, Biointerfaces, 81, 397-405.

Byrne, M., Ball, D., Guerquin-Kern, J.-L., Rouiller, I., Wu, T.-D., Downing, K., Vali, H., & Komeili, A. (2010) Desulfovibrio magneticus RS-1 contains an iron and phosphorus-rich organelle distinct from its bullet-shaped magnetosomes. Proc. Natl. Acad. Sci. U.S.A., doi: 10.1073/pnas.1001290107.

Murat, D., Quinlin, A., Vali, H., Komeili, A. (2010) Comprehensive genetic dissection of the magnetosome gene island reveals the stepwise assembly of a prokaryotic organelle. Proc. Natl.  Acad. Sci. U.S.A., 107:5593-5598.

Shahryari, A., Azari, F., Vali, H., Omanovic, S. (2010) The response of fibrinogen, platelets, endothelial and smooth muscle cells to an electrochemically modified SS316LS surface: towards the enhanced biocompatibility of coronary stents. Acta Biomater., 6, 695-701.

Mahmoudi, M., Simchi, A., Vali, H., Imani, M., Shokrgozar, M.A., Azadmanesh, K., & Azari, F.  (2009) Cytotoxicity and cell cycle effects of bare and polyvinyl alcohol coated iron oxide nanoparticles in mouse fibroblasts. Adv. Eng. Mat., 11, B243-B250.

Diez, G., Kollmannsberger, P., Mierke, C.T.,  Koch, T.M., Vali, H., Fabry, B. & Goldmann, W. H. (2009) Anchorage of vinculin to lipid membranes influences cell mechanical properties. Biophys. J., 97, 3105-3112.

Kopp, R.E., Schumann, D., Raub, T.D., Powars, D.S., Godfrey, L.V., Swanson-Hysell, N.L., Maloof, A.C. & Vali, H. (2009) An Appalachian Amazon?: Magnetofossil evidence for the development of a tropical river-like system in the mid-Atlantic U.S. during the Paleocene-Eocene Thermal Maximum. Paleoceanography, 24, PA4211, doi:10.1029/2009PA001783.

Shahryari, A., Azari, F., Vali, H. & Omanovic, S. (2009) The response of fibrinogen, platelets, endothelial and smooth muscle cells to an electrochemically modified SS316LS surface: Towards the enhanced biocompatibility of coronary stents. Acta Biomaterialia, doi:10.1016/j.actbio.2009.07.007.

Shahryari, A., Azari, F., Vali, H. & Omanovic, S. (2009) The positive influence of electrochemical cyclic potentiodynamic polarization (CPP) passivation of a SS316LS surface on its response to fibronectin and pre-osteoblasts. J. Phys. Chem., 11, 6218–6224.

Nafisi, S., Szpunar, J., Vali, H., & Ghomashchi, R. (2009) Grain misorientation in thixo-billets prepared by melt stirring. Mater. Character.,60, 938-945.

Chien, Y.-C., Masica, D.L., Gray, J.J., Nguyen, S., Vali, H. & McKee, M.D. (2009) Modulation of calcium oxalate dihydrate growth by selective crystal-face binding of phosphorylated osteopontin and poly-aspartate peptide showing occlusion by sectoral (compositional) zoning. J. Biol. Chem., 284, 23491-23501.

Li, Y.-L., Pfiffner, S.M., Dyar, D.M., Vali, H., Konhauser, K., Cole, D.J., Rondinone, A.J. & Phelps, T. (2009) Degeneration of biogenic superparamagnetic magnetite. Geobiology, 7, 25-34.

Zukor, H., Song, W., Liberman, A., Mui, J., Vali, H., Guerquin-Kern, J.-L., Fillebeen, C., Pantopoulos, K. & Schipper, H.M. (2009) HO-1-mediated macroautophagy: A mechanism for unregulated iron deposition in aging and degenerating neural tissues. J. Neurosci., 109, 776-791.

Faghihi, S., Azari, F., Szpunar, J.A., Vali, H., & Tabrizian, M. (2009) Titanium crystal orientation as a tool for the improved and regulated cell attachment.  J. Biomed. Mater. Res. A., doi 10.1002/jbm.a.32275.

Mahmoudi, M.,, Shokrgozar, M.A., Simchi, A., Imani, M., Milani, A.S., Stroeve, P., Vali, H., Haefeli U.O., & Bonakda, S. (2009) Multiphysics flow modeling and in vitro toxicity of iron oxide nanoparticles coated with polyvinyl alcohol. J. Phys. Chem. C, doi: 10.1021/jp809453v.

Weiss, B.P., Fong, L.E., Vali, H., Lima, E.A., Baudenbacher, F.J. (2008) Paleointensity of the ancient Martian magnetic field. J. Geophys. Res. Lett., 35, L23207, doi:10.1029/2008GL035585.

Kalantari, F., Auguste, P., Ziafazeli, T., Tzimas, G., Malmstom, L., Bioulac-Sage, P., Boismenu, D., Vali, H. & Chevet, E. (2008) Proteomics analysis of liver pathological calcification suggests a role for the IQ motif containing GTPase activating protein 1 in myofibroblast function. Proteom. Clin. Appli., 3, 307-321.

Schumann, D., Raub, T.D., Kopp, R.E., Guerquin-Kern, J.L., Wu, T.-D., Rouiller, I., Smirnov, A.V., Sears, S.K., Leucken, U., Hesse, R., Kirschvink, J.L. & Vali, H. (2008) Gigantism in unique biogenic magnetite at the Paleocene-Eocene Thermal Maximum. Proc. Natl.  Acad. Sci. U.S.A., 105, 17648-17653.

Coustenis, A, Vali, H. and 154 others. (2008) TandEM: Titan and Enceladus mission. Exp. Astron., doi 10.1007/s10686-008-9103-z.

Nafisi, S., Ghomashchi, R., & Vali, H. (2008) Eutectic nucleation in hypoeutectic Al-Si alloys. Mat. Character., 59, 1466-1473.

Chien, Y.-C., Hinke, M.T., Vali, H. & McKee, M. (2008) Ultrastructural matrix-mineral relationships in avian eggshell, and effects of osteopontin on calcite growth in vitro. J. Struct. Biol., 163, 84-99.

Azari, F., Vali, H., Guerquin-Kern, J.-L.,Wu, T.D., Croisy, A., Sears, S.K., Tabrizian, M. & McKee,

M.D. (2008) Intracellular precipitation of hydroxyl apatite mineral and implications for pathological

calcification. J. Struct. Biol., 162, 468-479.

Nafisi, S., Vali, H., Szpunar, J., & Ghomashchi, R. (2008) Microstructural improvement of semi- solid hypoeutectic Al-Si foundry alloys through boron addition. TMS-Light Metals Conference 2008, New Orleans, LA.

Nafisi, S., Szpunar, J., Vali, H., & Ghomashchi, R. (2007) Impact of grain refining on semi-solid metal processing TMS-Light Metals Conference 2007, Orlando, FL 703-706.

Kopp, R. E., Raub, T., Schumann, D., Vali, H., Smirnov, A., & Kirschvink, J.L. (2007) Magnetofossil spike during the Paleocene-Eocene Thermal Maximum, Paleoceanography,

Maloof, A.C., Kopp, R.E., Grotzinger, J.P., Fike, D.A., Bosak, T., Vali, H., Poussart, P.M., Weiss, B.P., & Kirschvink, J.L. (2007) Sedimentary iron cycling and the origin and preservation of magnetization in platform carbonate muds, Andros Island, Bahamas. Earth Planet. Sci. Lett,. 259, 581–598.

Faghihi, S., Azari, F., Szpunar, J.A., Zhilyaev, A.P., Vali, H. & Tabrizian, M. (2007) Cellular and molecular interactions between MC3T3-E1 pre-osteoblasts and nanostructured titanium produced by high-pressure torsion. Biomaterials, 28, 3887-3895.

Kalantari, F., Miao, D., Emadali, A., Tzimas, G.N., Goltzman, D., Vali, H., Chevet, E. & Auguste, P. (2007) Cell and molecular mechanisms of abnormal calcification following ischemia-reperfusion injury in human liver transplantation. Modern Pathol., 20, 357-366.

Soo, P., Sidorov, S., Mui, J., Bronstein, L., Vali, H., Eisenberg, A. & Maysinger, D. (2007) Gold-labeled block copolymer micelles reveal gold aggregates at multiple subcellular sites. Langmuir, 23, 4830-4836.

Moon, J.-W., Roh, Y., Lauf, R.J., Vali, H., Yeary, L.W., & Phelps, T. J., (2007) Microbial preparation of metal-substituted magnetite nanoparticles,  J. Microbiol. Methods, doi:10.1016/j.mimet.2007.04.012.

Faghihi, S., Zhilyaev, A.P., Szpunar, J.A., Azari, F., Vali, H. & Tabrizian, M. (2007) Nanostructuring of titanium material by high pressure torsion improves pre-osteoblast attachment, Adv. Mater., 19,1069-1073.

Kopp, R.E., Weiss, B.P., Maloof, A.C., Vali, H., Nash, C.Z., & Kirschvink, J.L. (2006) Chains, clumps, and strings: Magnetofossil taphonomy with ferromagnetic resonance spectroscopy. Earth Planet. Sci. Lett., 247,10-25. doi:10.1016/j.epsl.2006.05.001.

Roh, Y., Gao, H., Vali, H., Gao, W., Stapleton, R.D., Moon, J.-W., Phelps, T.J., Zhou, J. (2006) Metal reduction and iron biomineralization by a novel psychrotolerant (Fe(III)-reducing bacterium Shewanella loihica PV-4. Appl. Environ. Microbiol., 72, 3236-3244.

Roh, Y., Vali, H., Phelps, T.J., & Moon, J.W. (2006) Extracellular synthesis of magnetite and metal-substituted magnetite nanoparticles. J. Nanosci. Nanotechnol., 11, 3517-3520.

Chien, Y.-C., Mucci, A., Paquette, J., Sears, S. K. & Vali, H. (2006) Advantages of using TEM imaging of  Pt-C Replicas to study nanoscale surface structures of calcite microcrystals. Microscop. Microanal., 2, 302-10.

Faghihi, S., Azari, F., Bateni, M., Szpunar, J., Vali, H., & Tabrizian, M. (2006) The significance of crystallographic texture of titanium alloy substrates on pre-osteoblast responses. Biomaterials, 27, 3532–3539.

Gralnick, J.A., Vali, H., & Newman, D.K. (2006) Extracellular respiration of dimethyl sulfoxide by Shewanella oneidensis MR-1. Proc. Natl. Acad. Sci. U. S. A., 103, 4669–4674.

Li., Y.-L., Vali, H., Yang, J., Phelps, T.J., & Zhang, C.L. (2006) Reduction of iron oxides enhanced by a sulfate-reducing bacteria and biogenic H2S production. J. Geomicrobiol,. 23, 103-107.

Duxin, N., Lui, F., Vali, H., & Eisenberg, A. (2005) Cadmium sulphide quantum dots in morphologically tunable triblock copolymer aggregates. J. Am. Chem.  Soc., 127, 10063-10069.

Faghihi, S., Bateni, R., Azari, F., Szpunar, J.A., Vali, H., & Tabrizian, M. (2005) The role of crystallographic texture of Ti-6Al-4V alloy on cell proliferation and attachment. Mater. Sci. For., 495-497, 705-710.       

Speer, M.Y., Chien, Y.-C., Quan, M., Yang, H.-Y., Vali, H., McKee, M.D., & Giachelli, C.M. (2005) Smooth muscle cells deficient in osteopontin have enhanced susceptibility to calcification in vitro. Cardiovascular Res., 66, 324-333.


Selected older publications:

Catelas, I., Petit, A.,Vali, H., Fragiskatos, C., Meilleur, R., Zukor, D.J., Antoniou, J., & Huk, O.L. (2005) Quantitative analysis of macrophage apoptosis vs. necrosis induced by cobalt and chromium ions in vitro.  Biomaterials, 26, 2441-2453.

Tzimas, G.N., Afshar, M., Emadali, A., Chevet, E., Vali, H., & Metrakos, P.P. (2004) Correlation of cell necrosis and tissue calcification with ischemia/reperfusion injury after liver transplantation. Transplant Proc., 36, 1766-8.

Vali, H., Weiss, B., Li, Y.-L., Sears, S.K., Kim, S.S., Kirschvink, J.L., & Zhang, C.L. (2004) Formation of tabular single-domain magnetite induced by Geobacter metallireducens GS-15. Proc. Natl. Acad. Sci. U. S. A., 101, 16121-6.

Komeili, A., Vali, H., Beveridge, T.J., & Newman, D.K. (2004) Magnetosome vesicles are present before magnetite formation, and MamA is required for their activation. Proc. Natl. Acad. Sci. U. S. A., 101, 3839-3844.

Miranda, C.J., Makui, H., Soares, R.J., Bilodeau, M., Mui, J., Vali, H., Bertrand, R., Andrews, N.C., & Santos, M.M. (2003). Hfe deficiency increases susceptibility to cardiotoxicity and exacerbates changes in iron metabolism induced by doxorubicin. Blood, 102, 2574-2580.

Guo, T, Kit, Y.Y., Nicaud, J.-M., Le Dall, M.-T., Sears, S.K., Vali, H., Chan, H., Rachubinski, R.A., & Titorenko, V.I. (2003) Peroxisome division in the yeast Yarrowia lipolytica is regulated by a signal from inside the peroxisome. J. Cell Biol., 162, 1255-1266.

Shata, S., Hesse, R., Martin, R.F., & Vali, H. (2003) Expandability of anchizonal illite and chlorite: Significance for crystallinity development in the transition from diagenesis to metamorphism. Am. Mineral., 88, 748-761.

Romanek, C. S., Zhang, C. L., Li, Y., Horita, J., Cole, D. R., & Vali, H. (2003) Carbon and hydrogen isotope fractionations associated with dissimilatory iron-reducing bacteria. Chem. Geol., 195, 5-16.

Briedus, D.J., Khamsessan, A., McLaughlin, R., Vali, H., Panaritou, M. & Chan, E.C.S. (2002) Isolation of Campylobacteria fetus subsp. fetus from a patient with cellulitis. J. Clinical Microbiol., 40, 4792-4796

McLaughlin, R., Vali, H., Lau, P.C.K., Palfree, R., De Ciccio, A. Sirois, M., Ahmad, D., Villemur, R., Derosiers, M., & Chan, E.C.S. (2002) Are there naturally occurring pleomorphic bacteria in blood of healthy humans? J. Clinical Microbiol., 40, 4771-4775.

Thomas-Keprta, K.L., Clemett, S.J., Bazylinski, D.A., Kirschvink, J.L., McKay, D.S., Wentworth, S.J., Vali, H., Gibson Jr., E.K., & Romanek, C.S. (2002) Magnetofossils from ancient Mars: a robust biosignature in the martian meteorite ALH84001. Appl. Environ. Microbiol., 68, 3663-3672.

Weiss, B.P,. Vali, H., Baudenbacher, F.J., Kirschvink, J.L., Stewart, S.T., & Shuster, D.L. (2002) Records of an ancient Martian magnetic field in ALH84001. Earth Planet. Sci. Letts., 203, 449-463.

Thomas-Keprta, K.L., Clemett, S.J, Bazylinski, Kirschvink, J.L., D.A., McKay, D.S., Wentworth, S.J., Vali, H., Gibson, Jr., E.K., & Romanek, C.S. (2001) Truncated hexa-octahedral magnetite crystals in ALH 84001: Presumptive biogenesis. Proc. Natl. Acad. Sci. U.S.A., 98, 2164-2169.

Vali, H., McKee, M.D, Ciftcioglu, N., Sears, S.K., Plows, F.L., Chevet, E., Plavsic, M., Kajander, E.O., & Zare, R.N. (2001) Nanoforms: A new type of protein-associated mineralization. Geochem. Cosmochem. Acta, 65, 63 -74.

Weiss, B P., Kirschvink, J.L., Baudenbacher, Vali, H., Peters, N.T., Macdonald, F.A., Wikswo, J.P. A low temperature transfer of ALH84001 from Mars to Earth. Science, 290, 791 - 795.

Temman, M., Paquette, J. & Vali, H. (2000) Mn and Zn incorporation into calcite as a function of chlorine aqueous concentration. Geochem. Cosmochem. Acta, 64, 2417-2430.

Kirschvink, J., Maine, A., & Vali, H. (1997) Paleomagnetic evidence of a low-temperature origin of carbonate in the Martian meteorite ALH84001. Science, 275, 1629-1633.

Sears, S.K., Hesse, R., Vali, H., Elliott, W.C., Aronson, J.L., & Martin, R.F. (1998b) K-Ar ages of 2:1 clay minerals, Mackenzie Delta-Beaufort Sea region, Arctic Canada: significance of n-alkylammonium exchange. Can. Mineral., 36:1507-1524.

Zhang, C., Vali, H., Romanek, C.S., Phelps, T.J., & Liu, S.V. (1998) Formation of single-domain magnetite by a thermophilic bacterium. Am. Mineral., 83:1409-1418.

Moffitt, M., Vali, H., & Eisenberg, A. (1998) Assemblies of semiconductor nanoparticle in water soluble block copolymer aggregates. Chem. Mat., 10, 1021-1028.

McKay, D.S., Gibson Jr, E, Thomas-Keprta, K, & Vali, H. (1997) No 'nanofossils' in martian meteorite. Nature, 390, 454-455.

Kirschvink, J., Maine, A., & Vali, H. (1997) Paleomagnetic evidence of a low-temperature origin of carbonate in the Martian meteorite ALH84001. Science, 275, 1629-1633.

McKay, D.S., Thomas-Keprta, K.L., Gibson JR, E.K., Romanek, C.S, & Vali, H. (1996) Evaluating the evidence for past life on Mars. Science, 274, 2123-2124.

Paquette, J., Vali, H., & Mucci, A. (1996) TEM study of Pt-C replicas of calcite overgrowths precipitated from electrolyte solutions. Geochem. Cosmochem. Acta, 60, 4689-4699

McKay, D.S., Gibson Jr, E.K., Thomas-Keprta, K.L., Vali, H., Romanek, C.S., Clemett, S.J., Chillier, X.D.F., Maechling, C.R. & Zare, R.N. (1996) Search for past life on Mars: Possible relic biogenic activity in Martian meteorite ALH84001. Science, 273, 924-930

Stanjek, H., Fassbinder, J., Vali, H., Waegle, H., & Graf, W. (1994) Evidence of biogenic greigite (ferrimagnetic Fe3S4) in soil. Eur. J. Soil Sci., 45, 97-103

Vali, H., Martin R.F., Amarantidis, G. & Morteani, G. (1993) Smectite-group minerals in deep-sea sediments: Monomineralic solid-solution or multiphase mixtures? Am. Mineral., 78, 1217-1229.

Vali, H., Hesse, R. & Kohler, E. (1991) Combined freeze-etch replicas and HRTEM imaging as tools to study the fundamental particles and the multi phase Nature of 2:1 layer silicates. Am. Mineral., 76, 1973-1984.

Vali, H. & Hesse R. (1990) Alkylammonium ion treatment of clay minerals in ultrathin section: A new method for HRTEM examination of expandable layers. Am. Mineral., 75, 1443-1446.

Vali, H. & Kirschvink, J. (1990) Observation of magnetosome organization, surface structure and iron biomineralization of undescribed magnetic bacteria: Evolutionary Speculations. In: Blakemore, R.P. and Frankel, R.B., Plenum Publishing Corporation pp 97-115.

Fassbinder, J.W.E., Stanjek, H. & Vali, H. (1990) Occurrence of magnetic bacteria in soil. Nature, 343, 161-163.

Vali, H. & Kirschvink, J. (1989) Magnetofossil dissolution in a paleomagnetically unstable deep sea sediment. Nature, 339, 2203-206.

Vali, H. & Bachmann, L. (1988) Ultrastructure and flow behavior of colloidal smectite dispersions. J. Colloid Interface Sci., 126, 278-291.

Vali, H., Föster, O., Amarantidis, G. & Petersen, N. (1987) Magnetotactic bacteria and their magnetofossils in sediments. Earth Planet. Science Lett,. 6, 389-400.

Petersen, N., von Dobeneck, T & Vali, H. (1986) Fossil bacterial magnetite in deep-sea sediments from the South Atlantic Ocean. Nature, 320, 611-615.