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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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SEM-EDX analysis of two areas from a precipitate recovered and dried after 30 days of aging in the sterile DSMZ medium.Images on the left show two levels of magnification of same area. Images on the right show EDX spectrum of two distinct areas of the sample.
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pone-0089480-g007: SEM-EDX analysis of two areas from a precipitate recovered and dried after 30 days of aging in the sterile DSMZ medium.Images on the left show two levels of magnification of same area. Images on the right show EDX spectrum of two distinct areas of the sample.

Mentions: In contrast SEM imaging of the solid recovered from the sterile DSMZ medium revealed the presence of smooth spherical aggregates of 1–2 µm diameter (Figure 7). Their EDS analysis showed considerable variation in elemental composition within the following ranges: Ca (30–42), O (28–44) and Mg (4–5) while phosphorus remained constant around 24 dry wt.%.


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)

SEM-EDX analysis of two areas from a precipitate recovered and dried after 30 days of aging in the sterile DSMZ medium.Images on the left show two levels of magnification of same area. Images on the right show EDX spectrum of two distinct areas of the sample.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0089480-g007: SEM-EDX analysis of two areas from a precipitate recovered and dried after 30 days of aging in the sterile DSMZ medium.Images on the left show two levels of magnification of same area. Images on the right show EDX spectrum of two distinct areas of the sample.
Mentions: In contrast SEM imaging of the solid recovered from the sterile DSMZ medium revealed the presence of smooth spherical aggregates of 1–2 µm diameter (Figure 7). Their EDS analysis showed considerable variation in elemental composition within the following ranges: Ca (30–42), O (28–44) and Mg (4–5) while phosphorus remained constant around 24 dry wt.%.

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