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Viruses Occur Incorporated in Biogenic High-Mg Calcite from Hypersaline Microbial Mats.

De Wit R, Gautret P, Bettarel Y, Roques C, Marlière C, Ramonda M, Nguyen Thanh T, Tran Quang H, Bouvier T - PLoS ONE (2015)

Bottom Line: Energy-dispersive X-ray spectrometer analysis revealed that they contain nitrogen and phosphorus in a molar ratio of ~9, which is typical for viruses.Nucleic acid staining revealed that they contain DNA or RNA.In addition, we showed that acid treatment (dissolution of calcite) resulted in release of viruses into suspension and estimated that there were ~15 × 10(9) viruses per g of calcite.

View Article: PubMed Central - PubMed

Affiliation: Centre for Marine Biodiversity, Exploitation and Conservation (MARBEC),Université de Montpellier, CNRS, IRD, Ifremer, Place Eugène Bataillon, Case 093, 34095, Montpellier, France.

ABSTRACT
Using three different microscopy techniques (epifluorescence, electronic and atomic force microscopy), we showed that high-Mg calcite grains in calcifying microbial mats from the hypersaline lake "La Salada de Chiprana", Spain, contain viruses with a diameter of 50-80 nm. Energy-dispersive X-ray spectrometer analysis revealed that they contain nitrogen and phosphorus in a molar ratio of ~9, which is typical for viruses. Nucleic acid staining revealed that they contain DNA or RNA. As characteristic for hypersaline environments, the concentrations of free and attached viruses were high (>10(10) viruses per g of mat). In addition, we showed that acid treatment (dissolution of calcite) resulted in release of viruses into suspension and estimated that there were ~15 × 10(9) viruses per g of calcite. We suggest that virus-mineral interactions are one of the possible ways for the formation of nano-sized structures often described as "nanobacteria" and that viruses may play a role in initiating calcification.

No MeSH data available.


Related in: MedlinePlus

Virus observed in different depth layers (see below) and different fractions of the microbial mat dominated by diatoms, Coleofasciculus chthonoplastes, and Chloroflexus-like bacteria (CLB), sampled in September 2007.A: Virus counts in the extracted water fraction (pore water and water soaked into the extracellular polymer matrix). B: Virus attached to solid organic and mineral matter. (circles = without acidification, squares = after 10 min of acidification, see Methods). C: Virus associated with extracted and purified carbonate grains observed on the outside of the carbonate grains (circles) and after 10 min of acidification (squares). See Methods for details. Description of the different layers: I: the yellow brown toplayer (0–1 ± 0.1 mm depth) was dominated by the diatom species belonging to the genera Frustula, Cymbella, Denticula, Nitzschia; II: layer B (1 ± 0.1 mm to 2.3 ± 0.2 mm depth) comprised bundles of C. chthonoplastes and filaments of CLB; III: layer (2.3 ± 0.2 mm to 3.9 ± 0.2 mm depth) corresponding to a transition zone with C. chthonoplastes and filaments of CLB, some of them showing signs of degradation; IV: deeply black coloured sediment (3.9 ± 0.3 mm to 5 ± 0.3 mm depth); V: layer (5 ± 0.3 mm to 6.4 ± 0.4 mm depth) was grey coloured with a lot of sand grains, other mineral particles. Biogenic high-Mg calcite grains were observed by microscopy in layers I, II, III, and IV.
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pone.0130552.g002: Virus observed in different depth layers (see below) and different fractions of the microbial mat dominated by diatoms, Coleofasciculus chthonoplastes, and Chloroflexus-like bacteria (CLB), sampled in September 2007.A: Virus counts in the extracted water fraction (pore water and water soaked into the extracellular polymer matrix). B: Virus attached to solid organic and mineral matter. (circles = without acidification, squares = after 10 min of acidification, see Methods). C: Virus associated with extracted and purified carbonate grains observed on the outside of the carbonate grains (circles) and after 10 min of acidification (squares). See Methods for details. Description of the different layers: I: the yellow brown toplayer (0–1 ± 0.1 mm depth) was dominated by the diatom species belonging to the genera Frustula, Cymbella, Denticula, Nitzschia; II: layer B (1 ± 0.1 mm to 2.3 ± 0.2 mm depth) comprised bundles of C. chthonoplastes and filaments of CLB; III: layer (2.3 ± 0.2 mm to 3.9 ± 0.2 mm depth) corresponding to a transition zone with C. chthonoplastes and filaments of CLB, some of them showing signs of degradation; IV: deeply black coloured sediment (3.9 ± 0.3 mm to 5 ± 0.3 mm depth); V: layer (5 ± 0.3 mm to 6.4 ± 0.4 mm depth) was grey coloured with a lot of sand grains, other mineral particles. Biogenic high-Mg calcite grains were observed by microscopy in layers I, II, III, and IV.

Mentions: The mat sampled in September 2007 represented a slightly more developed mat of C. chthonoplastes and CLB together with diatoms. The top layer I was dominated by diatoms and the layer II by communities of C. chthonoplastes associated with CLB on top of older degrading mat (III) and sediment (IV and V). In general, both the concentrations of freely suspended viruses in the extracted water and the viruses attached to the solid organic matter and mineral particles were higher in September than in March (cf. Fig 1A and 1B with 2A and 2B). In the four top layers (I–IV), where we observed biogenic (Ca,Mg)CO3 minerals in high amounts, the acidification resulted in increased viruses counts ranging from 51 to 12%, observed in layers I and IV, respectively (see Fig 2B). Again this increase is attributed to the liberation of viruses included in the carbonate grains. Only in layer V, we observed a decrease of 37% of viruses that can be explained to a large extent to losses induced by acidification.


Viruses Occur Incorporated in Biogenic High-Mg Calcite from Hypersaline Microbial Mats.

De Wit R, Gautret P, Bettarel Y, Roques C, Marlière C, Ramonda M, Nguyen Thanh T, Tran Quang H, Bouvier T - PLoS ONE (2015)

Virus observed in different depth layers (see below) and different fractions of the microbial mat dominated by diatoms, Coleofasciculus chthonoplastes, and Chloroflexus-like bacteria (CLB), sampled in September 2007.A: Virus counts in the extracted water fraction (pore water and water soaked into the extracellular polymer matrix). B: Virus attached to solid organic and mineral matter. (circles = without acidification, squares = after 10 min of acidification, see Methods). C: Virus associated with extracted and purified carbonate grains observed on the outside of the carbonate grains (circles) and after 10 min of acidification (squares). See Methods for details. Description of the different layers: I: the yellow brown toplayer (0–1 ± 0.1 mm depth) was dominated by the diatom species belonging to the genera Frustula, Cymbella, Denticula, Nitzschia; II: layer B (1 ± 0.1 mm to 2.3 ± 0.2 mm depth) comprised bundles of C. chthonoplastes and filaments of CLB; III: layer (2.3 ± 0.2 mm to 3.9 ± 0.2 mm depth) corresponding to a transition zone with C. chthonoplastes and filaments of CLB, some of them showing signs of degradation; IV: deeply black coloured sediment (3.9 ± 0.3 mm to 5 ± 0.3 mm depth); V: layer (5 ± 0.3 mm to 6.4 ± 0.4 mm depth) was grey coloured with a lot of sand grains, other mineral particles. Biogenic high-Mg calcite grains were observed by microscopy in layers I, II, III, and IV.
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pone.0130552.g002: Virus observed in different depth layers (see below) and different fractions of the microbial mat dominated by diatoms, Coleofasciculus chthonoplastes, and Chloroflexus-like bacteria (CLB), sampled in September 2007.A: Virus counts in the extracted water fraction (pore water and water soaked into the extracellular polymer matrix). B: Virus attached to solid organic and mineral matter. (circles = without acidification, squares = after 10 min of acidification, see Methods). C: Virus associated with extracted and purified carbonate grains observed on the outside of the carbonate grains (circles) and after 10 min of acidification (squares). See Methods for details. Description of the different layers: I: the yellow brown toplayer (0–1 ± 0.1 mm depth) was dominated by the diatom species belonging to the genera Frustula, Cymbella, Denticula, Nitzschia; II: layer B (1 ± 0.1 mm to 2.3 ± 0.2 mm depth) comprised bundles of C. chthonoplastes and filaments of CLB; III: layer (2.3 ± 0.2 mm to 3.9 ± 0.2 mm depth) corresponding to a transition zone with C. chthonoplastes and filaments of CLB, some of them showing signs of degradation; IV: deeply black coloured sediment (3.9 ± 0.3 mm to 5 ± 0.3 mm depth); V: layer (5 ± 0.3 mm to 6.4 ± 0.4 mm depth) was grey coloured with a lot of sand grains, other mineral particles. Biogenic high-Mg calcite grains were observed by microscopy in layers I, II, III, and IV.
Mentions: The mat sampled in September 2007 represented a slightly more developed mat of C. chthonoplastes and CLB together with diatoms. The top layer I was dominated by diatoms and the layer II by communities of C. chthonoplastes associated with CLB on top of older degrading mat (III) and sediment (IV and V). In general, both the concentrations of freely suspended viruses in the extracted water and the viruses attached to the solid organic matter and mineral particles were higher in September than in March (cf. Fig 1A and 1B with 2A and 2B). In the four top layers (I–IV), where we observed biogenic (Ca,Mg)CO3 minerals in high amounts, the acidification resulted in increased viruses counts ranging from 51 to 12%, observed in layers I and IV, respectively (see Fig 2B). Again this increase is attributed to the liberation of viruses included in the carbonate grains. Only in layer V, we observed a decrease of 37% of viruses that can be explained to a large extent to losses induced by acidification.

Bottom Line: Energy-dispersive X-ray spectrometer analysis revealed that they contain nitrogen and phosphorus in a molar ratio of ~9, which is typical for viruses.Nucleic acid staining revealed that they contain DNA or RNA.In addition, we showed that acid treatment (dissolution of calcite) resulted in release of viruses into suspension and estimated that there were ~15 × 10(9) viruses per g of calcite.

View Article: PubMed Central - PubMed

Affiliation: Centre for Marine Biodiversity, Exploitation and Conservation (MARBEC),Université de Montpellier, CNRS, IRD, Ifremer, Place Eugène Bataillon, Case 093, 34095, Montpellier, France.

ABSTRACT
Using three different microscopy techniques (epifluorescence, electronic and atomic force microscopy), we showed that high-Mg calcite grains in calcifying microbial mats from the hypersaline lake "La Salada de Chiprana", Spain, contain viruses with a diameter of 50-80 nm. Energy-dispersive X-ray spectrometer analysis revealed that they contain nitrogen and phosphorus in a molar ratio of ~9, which is typical for viruses. Nucleic acid staining revealed that they contain DNA or RNA. As characteristic for hypersaline environments, the concentrations of free and attached viruses were high (>10(10) viruses per g of mat). In addition, we showed that acid treatment (dissolution of calcite) resulted in release of viruses into suspension and estimated that there were ~15 × 10(9) viruses per g of calcite. We suggest that virus-mineral interactions are one of the possible ways for the formation of nano-sized structures often described as "nanobacteria" and that viruses may play a role in initiating calcification.

No MeSH data available.


Related in: MedlinePlus