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Carbonate Mineral Formation under the Influence of Limestone-Colonizing Actinobacteria: Morphology and Polymorphism.

Cao C, Jiang J, Sun H, Huang Y, Tao F, Lian B - Front Microbiol (2016)

Bottom Line: Mineralogical analyses showed that hexagonal prism calcite was only observed in the sub-surfaces of the mycelium pellets, which is a novel morphology mediated by microbes.Our analyses suggested that the effects of mycelium pellets as a molecular template almost gained an advantage over SMP both in crystal nucleation and growth, having nothing to do with biological activity.It is thereby convinced that lithophilous actinobacteria, S. luteogriseus DHS C014, owing to its advantageous genetic metabolism and filamentous structure, showed good biomineralization abilities, maybe it would have geoactive potential for biogenic carbonate in local microenvironments.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of SciencesGuiyang, China; Institute of Geochemistry, University of Chinese Academy of SciencesBeijing, China; The Key Laboratory of Biotechnology for Medicinal Plant of Jiangsu Province, School of Life Science, Jiangsu Normal UniversityXuzhou, China.

ABSTRACT
Microorganisms and their biomineralization processes are widespread in almost every environment on earth. In this work, Streptomyces luteogriseus DHS C014, a dominant lithophilous actinobacteria isolated from microbial mats on limestone rocks, was used to investigate its potential biomineralization to allow a better understanding of bacterial contributions to carbonate mineralization in nature. The ammonium carbonate free-drift method was used with mycelium pellets, culture supernatant, and spent culture of the strain. Mineralogical analyses showed that hexagonal prism calcite was only observed in the sub-surfaces of the mycelium pellets, which is a novel morphology mediated by microbes. Hemispheroidal vaterite appeared in the presence of spent culture, mainly because of the effects of soluble microbial products (SMP) during mineralization. When using the culture supernatant, doughnut-like vaterite was favored by actinobacterial mycelia, which has not yet been captured in previous studies. Our analyses suggested that the effects of mycelium pellets as a molecular template almost gained an advantage over SMP both in crystal nucleation and growth, having nothing to do with biological activity. It is thereby convinced that lithophilous actinobacteria, S. luteogriseus DHS C014, owing to its advantageous genetic metabolism and filamentous structure, showed good biomineralization abilities, maybe it would have geoactive potential for biogenic carbonate in local microenvironments.

No MeSH data available.


Related in: MedlinePlus

Morphologies of biominerals in CS treatments. Panel (A) Showing calcite with rhombohedral morphology and vaterite with hemispheroid morphology; (B,C) showing crystal details of calcite areas enclosed by dashed boxes on Panel (A); (D) showing crystal details of vaterite area enclosed by a dashed box on Panel (A) and EDS spectrum obtained from the asterisked site (the Au peak was the result of ion sputtering used before SEM examination); (E) showing doughnut-like vaterite; (F) showing details of the boxed area on Panel (E) and EDS spectrum obtained from the asterisked site.
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Figure 9: Morphologies of biominerals in CS treatments. Panel (A) Showing calcite with rhombohedral morphology and vaterite with hemispheroid morphology; (B,C) showing crystal details of calcite areas enclosed by dashed boxes on Panel (A); (D) showing crystal details of vaterite area enclosed by a dashed box on Panel (A) and EDS spectrum obtained from the asterisked site (the Au peak was the result of ion sputtering used before SEM examination); (E) showing doughnut-like vaterite; (F) showing details of the boxed area on Panel (E) and EDS spectrum obtained from the asterisked site.

Mentions: In CS treatments, an interesting aspect was that a rhombohedral calcite appeared in close contact with a hemispheroidal vaterite (Figure 9A). The following magnified images show that mycelia spread over the crystal surfaces, and were occasionally buried inside the crystal (arrows in Figures 9B,C). In addition, the crystal displayed its angles and edges of its (104) face with perfect cleavages. The vaterite crystal was fully covered by a network of mycelium, and it was hard to observe any details (Figure 9D). Furthermore, a good many doughnut-like crystals (Figure 9E) frequently appeared in this case. EDS data showed that Ca, C, and O were the major elements in these two shapes of crystals (Figures 9D,F). Na, K, and Cl, were introduced from the microbes. During mineralization process, these crystals were twinned with mycelia and braced firmly onto the mycelial mats. Thanks to this mycelial assistance, crystals here could easily develop from hemispheroid into spheroid form. However, the mycelia growing on these crystals can also hinder further crystal growth, and finally contributed to the doughnut-like crystals with their axial invagination. Unicellular bacteria described earlier could not contribute to the precipitation of doughnut-like crystals. In this case, small mycelia fragments could survive and grow slowly: this had less effects on the polymorphism than the SMP in the solution. On the contrary, another experiment was conducted that biomineralization occurred in the presence of washed mycelium pellets and spent culture. The results were consistent with MP treatments, indicating that mycelium pellets as a molecular template gained an advantage over SMP both in crystal nucleation and growth.


Carbonate Mineral Formation under the Influence of Limestone-Colonizing Actinobacteria: Morphology and Polymorphism.

Cao C, Jiang J, Sun H, Huang Y, Tao F, Lian B - Front Microbiol (2016)

Morphologies of biominerals in CS treatments. Panel (A) Showing calcite with rhombohedral morphology and vaterite with hemispheroid morphology; (B,C) showing crystal details of calcite areas enclosed by dashed boxes on Panel (A); (D) showing crystal details of vaterite area enclosed by a dashed box on Panel (A) and EDS spectrum obtained from the asterisked site (the Au peak was the result of ion sputtering used before SEM examination); (E) showing doughnut-like vaterite; (F) showing details of the boxed area on Panel (E) and EDS spectrum obtained from the asterisked site.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834437&req=5

Figure 9: Morphologies of biominerals in CS treatments. Panel (A) Showing calcite with rhombohedral morphology and vaterite with hemispheroid morphology; (B,C) showing crystal details of calcite areas enclosed by dashed boxes on Panel (A); (D) showing crystal details of vaterite area enclosed by a dashed box on Panel (A) and EDS spectrum obtained from the asterisked site (the Au peak was the result of ion sputtering used before SEM examination); (E) showing doughnut-like vaterite; (F) showing details of the boxed area on Panel (E) and EDS spectrum obtained from the asterisked site.
Mentions: In CS treatments, an interesting aspect was that a rhombohedral calcite appeared in close contact with a hemispheroidal vaterite (Figure 9A). The following magnified images show that mycelia spread over the crystal surfaces, and were occasionally buried inside the crystal (arrows in Figures 9B,C). In addition, the crystal displayed its angles and edges of its (104) face with perfect cleavages. The vaterite crystal was fully covered by a network of mycelium, and it was hard to observe any details (Figure 9D). Furthermore, a good many doughnut-like crystals (Figure 9E) frequently appeared in this case. EDS data showed that Ca, C, and O were the major elements in these two shapes of crystals (Figures 9D,F). Na, K, and Cl, were introduced from the microbes. During mineralization process, these crystals were twinned with mycelia and braced firmly onto the mycelial mats. Thanks to this mycelial assistance, crystals here could easily develop from hemispheroid into spheroid form. However, the mycelia growing on these crystals can also hinder further crystal growth, and finally contributed to the doughnut-like crystals with their axial invagination. Unicellular bacteria described earlier could not contribute to the precipitation of doughnut-like crystals. In this case, small mycelia fragments could survive and grow slowly: this had less effects on the polymorphism than the SMP in the solution. On the contrary, another experiment was conducted that biomineralization occurred in the presence of washed mycelium pellets and spent culture. The results were consistent with MP treatments, indicating that mycelium pellets as a molecular template gained an advantage over SMP both in crystal nucleation and growth.

Bottom Line: Mineralogical analyses showed that hexagonal prism calcite was only observed in the sub-surfaces of the mycelium pellets, which is a novel morphology mediated by microbes.Our analyses suggested that the effects of mycelium pellets as a molecular template almost gained an advantage over SMP both in crystal nucleation and growth, having nothing to do with biological activity.It is thereby convinced that lithophilous actinobacteria, S. luteogriseus DHS C014, owing to its advantageous genetic metabolism and filamentous structure, showed good biomineralization abilities, maybe it would have geoactive potential for biogenic carbonate in local microenvironments.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of SciencesGuiyang, China; Institute of Geochemistry, University of Chinese Academy of SciencesBeijing, China; The Key Laboratory of Biotechnology for Medicinal Plant of Jiangsu Province, School of Life Science, Jiangsu Normal UniversityXuzhou, China.

ABSTRACT
Microorganisms and their biomineralization processes are widespread in almost every environment on earth. In this work, Streptomyces luteogriseus DHS C014, a dominant lithophilous actinobacteria isolated from microbial mats on limestone rocks, was used to investigate its potential biomineralization to allow a better understanding of bacterial contributions to carbonate mineralization in nature. The ammonium carbonate free-drift method was used with mycelium pellets, culture supernatant, and spent culture of the strain. Mineralogical analyses showed that hexagonal prism calcite was only observed in the sub-surfaces of the mycelium pellets, which is a novel morphology mediated by microbes. Hemispheroidal vaterite appeared in the presence of spent culture, mainly because of the effects of soluble microbial products (SMP) during mineralization. When using the culture supernatant, doughnut-like vaterite was favored by actinobacterial mycelia, which has not yet been captured in previous studies. Our analyses suggested that the effects of mycelium pellets as a molecular template almost gained an advantage over SMP both in crystal nucleation and growth, having nothing to do with biological activity. It is thereby convinced that lithophilous actinobacteria, S. luteogriseus DHS C014, owing to its advantageous genetic metabolism and filamentous structure, showed good biomineralization abilities, maybe it would have geoactive potential for biogenic carbonate in local microenvironments.

No MeSH data available.


Related in: MedlinePlus