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The role of Carboxydothermus hydrogenoformans in the conversion of calcium phosphate from amorphous to crystalline state.

Haddad M, Vali H, Paquette J, Guiot SR - PLoS ONE (2014)

Bottom Line: The first of these solids occurred as micrometric clusters of blocky, angular crystals, which were associated with bacterial biofilm.Since Mg is known to be a strong inhibitor of the nucleation and growth of CaP, C. hydrogenoformans may act by providing sites that chelate Mg or form complexes with it, thus decreasing its activity as nucleation and crystal growth inhibitor.The synthesis of whitlockite and nano-HAP-like material by C. hydrogenoformans demonstrates the versatility of this organism also known for its ability to perform the water-gas shift reaction, and may have applications in bacterially mediated synthesis of CaP materials, as an environmentally friendly alternative process.

View Article: PubMed Central - PubMed

Affiliation: Energy, Mining and Environment Portfolio, National Research Council Canada, Montreal, Quebec, Canada ; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada.

ABSTRACT
Two previously unknown modes of biomineralization observed in the presence of Carboxydothermus hydrogenoformans are presented. Following the addition of NaHCO3 and the formation of an amorphous calcium phosphate precipitate in a DSMZ medium inoculated with C. hydrogenoformans, two distinct crystalline solids were recovered after 15 and 30 days of incubation. The first of these solids occurred as micrometric clusters of blocky, angular crystals, which were associated with bacterial biofilm. The second solid occurred as 30-50 nm nanorods that were found scattered among the organic products of bacterial lysis. The biphasic mixture of solids was clearly dominated by the first phase. The X-ray diffractometry (XRD) peaks and Fourier transform infrared spectroscopy (FTIR) spectrum of this biphasic material consistently showed features characteristic of Mg-whitlockite. No organic content or protein could be identified by dissolving the solids. In both cases, the mode of biomineralization appears to be biologically induced rather than biologically controlled. Since Mg is known to be a strong inhibitor of the nucleation and growth of CaP, C. hydrogenoformans may act by providing sites that chelate Mg or form complexes with it, thus decreasing its activity as nucleation and crystal growth inhibitor. The synthesis of whitlockite and nano-HAP-like material by C. hydrogenoformans demonstrates the versatility of this organism also known for its ability to perform the water-gas shift reaction, and may have applications in bacterially mediated synthesis of CaP materials, as an environmentally friendly alternative process.

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XRD spectra of the dried precipitate recovered after 30 days of C. hydrogenoformans growth in the DSMZ medium (identified as ‘Dried sample’), the dried sample after having been calcinated (identified as ‘Calcinated sample’), the commercial sintered β-TCP, and the whitlockite, calculated according to the JCPDS (Joint Committee on Powder Diffraction Standards) database (number 01-070-1786).
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pone-0089480-g003: XRD spectra of the dried precipitate recovered after 30 days of C. hydrogenoformans growth in the DSMZ medium (identified as ‘Dried sample’), the dried sample after having been calcinated (identified as ‘Calcinated sample’), the commercial sintered β-TCP, and the whitlockite, calculated according to the JCPDS (Joint Committee on Powder Diffraction Standards) database (number 01-070-1786).

Mentions: The XRD pattern (Figure 2) of solids recovered after 30 days in the inoculated DSMZ medium showed sharp peaks at the same angles as the one of whitlockite XRD pattern from the JCPDS database (file number 01-070-1786). Lattice parameters of these solids were determined as a = 10,330 A° and c = 37,103 A°, in agreement with those reported from natural whitlockite [26]. The calculated value of crystallite size was 30 nm compared to the crystallite size of 102 nm for the commercial β-TCP. The calculated crystallinity of the dried-only solid was 91.7%. After calcination (600°C) in air for 1 h, the solid showed 100% crystallinity (Figure 3). By comparison, the XRD spectrum (Figure 4) of the solid recovered after 30 days of aging in the sterile DSMZ medium showed a broad hump around 30° and no sharp peaks, suggesting either a total lack of crystallinity or barely incipient nanocrystallinity.


The role of Carboxydothermus hydrogenoformans in the conversion of calcium phosphate from amorphous to crystalline state.

Haddad M, Vali H, Paquette J, Guiot SR - PLoS ONE (2014)

XRD spectra of the dried precipitate recovered after 30 days of C. hydrogenoformans growth in the DSMZ medium (identified as ‘Dried sample’), the dried sample after having been calcinated (identified as ‘Calcinated sample’), the commercial sintered β-TCP, and the whitlockite, calculated according to the JCPDS (Joint Committee on Powder Diffraction Standards) database (number 01-070-1786).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3935887&req=5

pone-0089480-g003: XRD spectra of the dried precipitate recovered after 30 days of C. hydrogenoformans growth in the DSMZ medium (identified as ‘Dried sample’), the dried sample after having been calcinated (identified as ‘Calcinated sample’), the commercial sintered β-TCP, and the whitlockite, calculated according to the JCPDS (Joint Committee on Powder Diffraction Standards) database (number 01-070-1786).
Mentions: The XRD pattern (Figure 2) of solids recovered after 30 days in the inoculated DSMZ medium showed sharp peaks at the same angles as the one of whitlockite XRD pattern from the JCPDS database (file number 01-070-1786). Lattice parameters of these solids were determined as a = 10,330 A° and c = 37,103 A°, in agreement with those reported from natural whitlockite [26]. The calculated value of crystallite size was 30 nm compared to the crystallite size of 102 nm for the commercial β-TCP. The calculated crystallinity of the dried-only solid was 91.7%. After calcination (600°C) in air for 1 h, the solid showed 100% crystallinity (Figure 3). By comparison, the XRD spectrum (Figure 4) of the solid recovered after 30 days of aging in the sterile DSMZ medium showed a broad hump around 30° and no sharp peaks, suggesting either a total lack of crystallinity or barely incipient nanocrystallinity.

Bottom Line: The first of these solids occurred as micrometric clusters of blocky, angular crystals, which were associated with bacterial biofilm.Since Mg is known to be a strong inhibitor of the nucleation and growth of CaP, C. hydrogenoformans may act by providing sites that chelate Mg or form complexes with it, thus decreasing its activity as nucleation and crystal growth inhibitor.The synthesis of whitlockite and nano-HAP-like material by C. hydrogenoformans demonstrates the versatility of this organism also known for its ability to perform the water-gas shift reaction, and may have applications in bacterially mediated synthesis of CaP materials, as an environmentally friendly alternative process.

View Article: PubMed Central - PubMed

Affiliation: Energy, Mining and Environment Portfolio, National Research Council Canada, Montreal, Quebec, Canada ; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada.

ABSTRACT
Two previously unknown modes of biomineralization observed in the presence of Carboxydothermus hydrogenoformans are presented. Following the addition of NaHCO3 and the formation of an amorphous calcium phosphate precipitate in a DSMZ medium inoculated with C. hydrogenoformans, two distinct crystalline solids were recovered after 15 and 30 days of incubation. The first of these solids occurred as micrometric clusters of blocky, angular crystals, which were associated with bacterial biofilm. The second solid occurred as 30-50 nm nanorods that were found scattered among the organic products of bacterial lysis. The biphasic mixture of solids was clearly dominated by the first phase. The X-ray diffractometry (XRD) peaks and Fourier transform infrared spectroscopy (FTIR) spectrum of this biphasic material consistently showed features characteristic of Mg-whitlockite. No organic content or protein could be identified by dissolving the solids. In both cases, the mode of biomineralization appears to be biologically induced rather than biologically controlled. Since Mg is known to be a strong inhibitor of the nucleation and growth of CaP, C. hydrogenoformans may act by providing sites that chelate Mg or form complexes with it, thus decreasing its activity as nucleation and crystal growth inhibitor. The synthesis of whitlockite and nano-HAP-like material by C. hydrogenoformans demonstrates the versatility of this organism also known for its ability to perform the water-gas shift reaction, and may have applications in bacterially mediated synthesis of CaP materials, as an environmentally friendly alternative process.

Show MeSH
Related in: MedlinePlus