Loosely bound iron, due to its contribution to oxidative stress and inflammation, has become an i... more Loosely bound iron, due to its contribution to oxidative stress and inflammation, has become an important therapeutic target for many diseases. A water-soluble chitosan-based polymer exhibiting both antioxidant and chelating properties due to the dual functionalization with DOTAGA and DFO has been developed to extract this iron therefore preventing its catalytic production of reactive oxygen species. This functionalized chitosan was shown to have stronger antioxidant properties compared to conventional chitosan, improved iron chelating properties compared to the clinical therapy, deferiprone, and provided promising results for its application and improved metal extraction within a conventional 4 h hemodialysis session with bovine plasma.
Heavy metals present a threat to human health, even at minimal concentrations within the body. On... more Heavy metals present a threat to human health, even at minimal concentrations within the body. One source of exposure is due to the consumption of low-level contaminated foodstuff and water. Lead and cadmium have been shown to be absorbed by and accumulate within organs like the kidneys and liver, and they have also been associated to many diseases including cardiovascular disease and kidney dysfunction as well as developmental disorders and neurodegenerative diseases. Since this contamination of lead and cadmium is found worldwide, limiting the exposure is complicated and novel strategies are required to prevent the absorption and accumulation of these metals by forcing their elimination. In this study, a DOTAGA-functionalized chitosan polymer is evaluated for this preventative strategy. It shows promising results when orally administered in mice to force the elimination and negate the toxic effects of lead and cadmium found within foodstuff.
Figure S1. Full amoA (A) and 16S rRNA (B) gene trees for the bacterial ammonia oxidiser reference... more Figure S1. Full amoA (A) and 16S rRNA (B) gene trees for the bacterial ammonia oxidiser reference sequences. Figure S2. Congruence of amoA and 16S rRNA gene phylogenetic trees for the bacterial ammonia oxidiser reference sequences. Shades of blue indicate similarity between the most common nodes between the two trees. Figure S3. Full bacterial amoA gene tree including the environmental sequences (assembled using the MiSeq 'Assembly' pipeline) and the reference sequences. Figure S4. Congruence between two phylogenetic trees of 370 archaeal amoA sequences (see Gubry-Rangin et al., 2015) with (A) or without (B) the sequence gap corresponding to the MiSeq AOA gap pipeline. Branch colour corresponds to congruence between the two trees. Table S1. Identification of sequences of the 56 terrestrial Nitrosospira AOB strains used in this study. For strains with > 1 copy, only the sequences used in this study presented. n.a. – not applicable. Table S2. Statistical results of the cano...
In this article, we report the conception and the use of dialysis-based medical device for the ex... more In this article, we report the conception and the use of dialysis-based medical device for the extraction of metals. The medical device is obtained by addition in the dialysate of a functionalized chitosan that can chelate endogenous metals like iron or copper. This water-soluble functionalized chitosan is obtained after controlled reacetylation and grafting of DOTAGA. Due to the high mass of chitosan, the polymer cannot cross through the membrane and the metals are trapped in the dialysate during hemodialysis. Copper extraction has been evaluated in vitro using an hemodialysis protocol. Feasibility study has been performed on healthy sheep showing no acute toxicity througout the entire dialysis procedure and first insights of metallic extraction even on healthy animals.
Even though organic waste (OW) recycling via anaerobic digestion (AD) and composting are increasi... more Even though organic waste (OW) recycling via anaerobic digestion (AD) and composting are increasingly used, little is known about the impact of OW origin (fecal matters and food and vegetable wastes) on the end products’ bacterial contents. The hypothesis of a predictable bacterial community structure in the end products according to the OW origin was tested. Nine OW treatment plants were selected to assess the genetic structure of bacterial communities found in raw OW according to their content in agricultural and urban wastes and to estimate their modifications through AD and composting. Two main bacterial community structures among raw OWs were observed and matched a differentiation according to the occurrences of urban chemical pollutants. Composting led to similar 16S rRNA gene OTU profiles whatever the OW origin. With a significant shift of about 140 genera (representing 50% of the bacteria), composting was confirmed to largely shape bacterial communities toward similar struct...
Shewanella algae C6G3 can reduce dissimilatively nitrate into ammonium and manganese-oxide (MnIV)... more Shewanella algae C6G3 can reduce dissimilatively nitrate into ammonium and manganese-oxide (MnIV) into MnII. It has the unusual ability to produce anaerobically nitrite from ammonium in the presence of MnIV. To gain insight into their metabolic capabilities, global mRNA expression patterns were investigated by RNA-seq and qRT-PCR in cells growing with lactate and ammonium as carbon and nitrogen sources and with either MnIV or nitrate as electron acceptors. Gene exhibiting higher expression levels in the presence of MnIV belonged to functional categories of carbohydrate, coenzyme, lipid metabolisms and inorganic ion transport. Comparative transcriptomic pattern between MnIV and NO3 revealed that the strain presented an ammonium limitation status with MnIV, despite the presence of non-limiting concentration of ammonium under both culture conditions. In addition, in presence of MnIV, ntrB/nrtC regulators, ammonium channel, nitrogen regulatory protein P-II, glutamine synthetase and aspa...
ABSTRACT Field measurements in the Arcachon Bay (southwest France) indicated anaerobic production... more ABSTRACT Field measurements in the Arcachon Bay (southwest France) indicated anaerobic production of NOx via nitrifica- tion, which was coupled to the reduction of Mn-oxides. To prove the occurrence of this process, laboratory microcosm experiments were set up. A 15N tracer-based approach was used to track if NOx produced through Mn-oxide-mediated anaerobic nitrification would be reduced to N2 via denitrification or anammox. We also hy- pothesized the generation of the potent greenhouse gas nitrous oxide (N2O) during nitrification–denitrification in the presence of Mn-oxides. The microcosms were prepared using sediment sectioned at varying depths (0–2.5, 2.5–4.5, 4.5–8.5, 8.5–12 and 12–17 cm) during two sampling campaigns in October (fall) and January (winter). Labeling with 15NO−3 revealed low N2 production originating from NO−3 in the water column (Pw), which did not increase significantly on amendment with Mn-oxides during both sampling periods. However, for both sea- sons, a significant increase of N2 produced via nitrification (Pn) was observed upon addition of Mn-oxides reaching 76-fold enhancement at ≤ 2.5 cm. To support these results, sediment slurries of October were subjected to amendment of 15NH+4 , 14NO−3 with or without addition of Mn-oxides. A substantial production of P15 (N2 production from 15NH+4 ) within 0–17 cm provided further evidence on nitrification–denitrification mediated by Mn-oxides probably with minimal intervention of anammox. In organically rich sediments, anaerobic nitrifi- cation–denitrification mediated by Mn-oxides could play an important role in lowering re-mineralized NH+4 levels in the benthic system. As hypothesized, significant production of N2O through the pathway was observed revealing newer mechanisms leading to the generation of the radiative gas.
Loosely bound iron, due to its contribution to oxidative stress and inflammation, has become an i... more Loosely bound iron, due to its contribution to oxidative stress and inflammation, has become an important therapeutic target for many diseases. A water-soluble chitosan-based polymer exhibiting both antioxidant and chelating properties due to the dual functionalization with DOTAGA and DFO has been developed to extract this iron therefore preventing its catalytic production of reactive oxygen species. This functionalized chitosan was shown to have stronger antioxidant properties compared to conventional chitosan, improved iron chelating properties compared to the clinical therapy, deferiprone, and provided promising results for its application and improved metal extraction within a conventional 4 h hemodialysis session with bovine plasma.
Heavy metals present a threat to human health, even at minimal concentrations within the body. On... more Heavy metals present a threat to human health, even at minimal concentrations within the body. One source of exposure is due to the consumption of low-level contaminated foodstuff and water. Lead and cadmium have been shown to be absorbed by and accumulate within organs like the kidneys and liver, and they have also been associated to many diseases including cardiovascular disease and kidney dysfunction as well as developmental disorders and neurodegenerative diseases. Since this contamination of lead and cadmium is found worldwide, limiting the exposure is complicated and novel strategies are required to prevent the absorption and accumulation of these metals by forcing their elimination. In this study, a DOTAGA-functionalized chitosan polymer is evaluated for this preventative strategy. It shows promising results when orally administered in mice to force the elimination and negate the toxic effects of lead and cadmium found within foodstuff.
Figure S1. Full amoA (A) and 16S rRNA (B) gene trees for the bacterial ammonia oxidiser reference... more Figure S1. Full amoA (A) and 16S rRNA (B) gene trees for the bacterial ammonia oxidiser reference sequences. Figure S2. Congruence of amoA and 16S rRNA gene phylogenetic trees for the bacterial ammonia oxidiser reference sequences. Shades of blue indicate similarity between the most common nodes between the two trees. Figure S3. Full bacterial amoA gene tree including the environmental sequences (assembled using the MiSeq 'Assembly' pipeline) and the reference sequences. Figure S4. Congruence between two phylogenetic trees of 370 archaeal amoA sequences (see Gubry-Rangin et al., 2015) with (A) or without (B) the sequence gap corresponding to the MiSeq AOA gap pipeline. Branch colour corresponds to congruence between the two trees. Table S1. Identification of sequences of the 56 terrestrial Nitrosospira AOB strains used in this study. For strains with > 1 copy, only the sequences used in this study presented. n.a. – not applicable. Table S2. Statistical results of the cano...
In this article, we report the conception and the use of dialysis-based medical device for the ex... more In this article, we report the conception and the use of dialysis-based medical device for the extraction of metals. The medical device is obtained by addition in the dialysate of a functionalized chitosan that can chelate endogenous metals like iron or copper. This water-soluble functionalized chitosan is obtained after controlled reacetylation and grafting of DOTAGA. Due to the high mass of chitosan, the polymer cannot cross through the membrane and the metals are trapped in the dialysate during hemodialysis. Copper extraction has been evaluated in vitro using an hemodialysis protocol. Feasibility study has been performed on healthy sheep showing no acute toxicity througout the entire dialysis procedure and first insights of metallic extraction even on healthy animals.
Even though organic waste (OW) recycling via anaerobic digestion (AD) and composting are increasi... more Even though organic waste (OW) recycling via anaerobic digestion (AD) and composting are increasingly used, little is known about the impact of OW origin (fecal matters and food and vegetable wastes) on the end products’ bacterial contents. The hypothesis of a predictable bacterial community structure in the end products according to the OW origin was tested. Nine OW treatment plants were selected to assess the genetic structure of bacterial communities found in raw OW according to their content in agricultural and urban wastes and to estimate their modifications through AD and composting. Two main bacterial community structures among raw OWs were observed and matched a differentiation according to the occurrences of urban chemical pollutants. Composting led to similar 16S rRNA gene OTU profiles whatever the OW origin. With a significant shift of about 140 genera (representing 50% of the bacteria), composting was confirmed to largely shape bacterial communities toward similar struct...
Shewanella algae C6G3 can reduce dissimilatively nitrate into ammonium and manganese-oxide (MnIV)... more Shewanella algae C6G3 can reduce dissimilatively nitrate into ammonium and manganese-oxide (MnIV) into MnII. It has the unusual ability to produce anaerobically nitrite from ammonium in the presence of MnIV. To gain insight into their metabolic capabilities, global mRNA expression patterns were investigated by RNA-seq and qRT-PCR in cells growing with lactate and ammonium as carbon and nitrogen sources and with either MnIV or nitrate as electron acceptors. Gene exhibiting higher expression levels in the presence of MnIV belonged to functional categories of carbohydrate, coenzyme, lipid metabolisms and inorganic ion transport. Comparative transcriptomic pattern between MnIV and NO3 revealed that the strain presented an ammonium limitation status with MnIV, despite the presence of non-limiting concentration of ammonium under both culture conditions. In addition, in presence of MnIV, ntrB/nrtC regulators, ammonium channel, nitrogen regulatory protein P-II, glutamine synthetase and aspa...
ABSTRACT Field measurements in the Arcachon Bay (southwest France) indicated anaerobic production... more ABSTRACT Field measurements in the Arcachon Bay (southwest France) indicated anaerobic production of NOx via nitrifica- tion, which was coupled to the reduction of Mn-oxides. To prove the occurrence of this process, laboratory microcosm experiments were set up. A 15N tracer-based approach was used to track if NOx produced through Mn-oxide-mediated anaerobic nitrification would be reduced to N2 via denitrification or anammox. We also hy- pothesized the generation of the potent greenhouse gas nitrous oxide (N2O) during nitrification–denitrification in the presence of Mn-oxides. The microcosms were prepared using sediment sectioned at varying depths (0–2.5, 2.5–4.5, 4.5–8.5, 8.5–12 and 12–17 cm) during two sampling campaigns in October (fall) and January (winter). Labeling with 15NO−3 revealed low N2 production originating from NO−3 in the water column (Pw), which did not increase significantly on amendment with Mn-oxides during both sampling periods. However, for both sea- sons, a significant increase of N2 produced via nitrification (Pn) was observed upon addition of Mn-oxides reaching 76-fold enhancement at ≤ 2.5 cm. To support these results, sediment slurries of October were subjected to amendment of 15NH+4 , 14NO−3 with or without addition of Mn-oxides. A substantial production of P15 (N2 production from 15NH+4 ) within 0–17 cm provided further evidence on nitrification–denitrification mediated by Mn-oxides probably with minimal intervention of anammox. In organically rich sediments, anaerobic nitrifi- cation–denitrification mediated by Mn-oxides could play an important role in lowering re-mineralized NH+4 levels in the benthic system. As hypothesized, significant production of N2O through the pathway was observed revealing newer mechanisms leading to the generation of the radiative gas.
Uploads