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Philippis, Roberto De; Chen, Sili; Paperi, Raffaella; Vincenzini, Massimo

doi:10.1023/a:1017590425924

Cited by 245 publications

(57 citation statements)

References 38 publications

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“…It was explained that the Cyanobacteria dominates microbial mats, working as the most important group in the organomineralization producing exopolisaccharide (EPS) into the mats which is a pliant matrix for structuring associations within microbial communities [58]. EPS can be produced by a wide array of microorganisms, photoautotrophic bacteria as well as heterotrophic bacteria, although Cyanobacteria are believed to generate the bulk of the quantity, and the content might vary with different stressors and/or environmental conditions [59][60][61][62][63][64][65][66][67]. However, we observed that the cyanobacterial OTUs found in our samples are very scarce or absent.…”

Section: Discussionmentioning

confidence: 99%

Bacterial Diversity in Microbial Mats and Sediments from the Atacama Desert

et al. 2015

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The Atacama Desert has extreme environmental conditions that allow the development of unique microbial communities. The present paper reports the bacterial diversity of microbial mats and sediments and its mineralogical components. Some physicochemical conditions of the water surrounding these ecosystems have also been studied trying to determine their influence on the diversity of these communities. In that way, mats and sediments distributed among different hypersaline lakes located in salt flats of the Atacama Desert were subjected to massive parallel sequencing of the V4 region of the 16S rRNA genes of Bacteria. A higher diversity in sediment than in mat samples have been found. Lakes that harbor microbial mats have higher salinity than lakes where mats are absent. Proteobacteria and/or Bacteroidetes are the major phyla represented in all samples. An interesting item is the finding of a low proportion or absence of Cyanobacteria sequences in the ecosystems studied, suggesting the possibility that other groups may be playing an essential role as primary producers in these extreme environments. Additionally, the large proportion of 16S rRNA gene sequences that could not be classified at the level of phylum indicates potential new phyla present in these ecosystems.

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Section: Discussionmentioning

confidence: 99%

Bacterial Diversity in Microbial Mats and Sediments from the Atacama Desert

et al. 2015

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“…Moreover, the overall negative charge of cyanobacterial EPS may be essential for sequestering metal cations that are essential for cell growth but present at low concentrations in their surroundings, and/or preventing the direct contact between the cells and toxic heavy metals dispersed in the environment (De Philippis & Vincenzini, 2003;Pereira et al, 2009). The ability of EPS-producing cyanobacteria to remove heavy metals from aqueous solutions has been widely reported in the literature, focusing mainly on its biotechnological potential (De Philippis et al, 2001De Philippis & Vincenzini, 2003;Li et al, 2001). On the other hand, information about the effects of the metals on the physiology of cyanobacteria is still scarce particularly for situations of simultaneous exposure to more than one metal, which frequently occur in polluted environments (Baptista & Vasconcelos, 2006;Burnat et al, 2009;Fiore & Trevors, 1994;Heng et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Using extracellular polymeric substances (EPS)-producing cyanobacteria for the bioremediation of heavy metals: do cations compete for the EPS functional groups and also accumulate inside the cell?

et al. 2011

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Many cyanobacteria produce extracellular polymeric substances (EPS) mainly of polysaccharidic nature. These EPS can remain associated to the cell surface as sheaths, capsules and/or slimes, or be liberated into the surrounding environment as released polysaccharides (RPS). The ability of EPS-producing cyanobacteria to remove heavy metals from aqueous solutions has been widely reported in the literature, focusing mainly on the biotechnological potential. However, the knowledge of the effects of the metals in the cell's survival/growth is still scarce, particularly when they are simultaneously exposed to more than one metal. This work evaluated the effects of different concentrations of Cu 2+ and/or Pb 2+ in the growth/survival of Gloeothece sp. PCC 6909 and its sheathless mutant Gloeothece sp. CCY 9612. The results obtained clearly showed that both phenotypes are more severely affected by Cu 2+ than Pb 2+ , and that the mutant is more sensitive to the former metal than the wild-type. Evident ultrastructural changes were also observed in the wild-type and mutant cells exposed to high levels (10 mg l "1 ) of Cu 2+ . Moreover, in bi-metal systems, Pb 2+ was preferentially removed compared with Cu 2+ , being the RPS of the mutant that is the most efficient polysaccharide fraction in metal removal. In these systems, the simultaneous presence of Cu 2+ and Pb 2+ caused a mutual inhibition in the adsorption of each metal.

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“…Therefore, the EPS can be considered capping agents, which supports the process of AuNPs biosynthesis and prevents them from aggregating. In addition, most EPS are water-soluble polymers [48], so their presence at the NP surface improves the stability of colloidal gold in aqueous solutions. Similar findings had been published by Dahoumane and coauthors, who indicated the important role of EPS produced by photosynthetic organisms in the stabilization of AuNPs [24,29,31].…”

Section: Discussionmentioning

confidence: 99%

Formation of Variously Shaped Gold Nanoparticles by Anabaena laxa

et al. 2017

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Anew aspect of this study is the biocatalysis ability of Anabaena laxafresh-water strain-which to date has not been studied with respect to the formation of gold nanoparticles. The results of our study have shown that A. laxa is able to form gold nanoparticles (AuNPs) at good yields within 24 h of incubation at all three tested concentrations (0.1, 0.5 and 1 mM) of hydrogen tetrachloroaurate (III). After 24 h, nanoparticles were mostly localized in the growth medium, which significantly facilitates their isolation. However, the elongation of this process is accompanied by their concentration in the exopolysaccharide (EPS) layer of the cyanobacterial cells. There is a correlation between the initial concentration of the Au 3? cations and the formation of AuNPs of various shapes and a size. The comparison of activities of living and deactivated cells indicated that AuNPs were formed more efficiently when metabolically active cyanobacteria were used.

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Cited by 245 publications

References 38 publications

Bacterial Diversity in Microbial Mats and Sediments from the Atacama Desert

Bacterial Diversity in Microbial Mats and Sediments from the Atacama Desert

Using extracellular polymeric substances (EPS)-producing cyanobacteria for the bioremediation of heavy metals: do cations compete for the EPS functional groups and also accumulate inside the cell?

Formation of Variously Shaped Gold Nanoparticles by Anabaena laxa

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