Exploring ammonium conversion at bioanodes of MEC
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PROVIDER: PRJEB91738 | ENA |
REPOSITORIES: ENA
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Project description:Nitric oxide (NO) has several important functions in biology and atmospheric chemistry as a toxin, signaling molecule, ozone depleting agent and the precursor of the greenhouse gas nitrous oxide (N2O). Even though NO is a potent oxidant, and was available on earth earlier than oxygen, its direct use by microorganisms for growth was not demonstrated before. Using physiological experiments, metatranscriptomics and metaproteomics, here we show that anaerobic ammonium-oxidizing (anammox) bacterium Kuenenia stuttgartiensis grow by coupling ammonium oxidation to NO reduction, and produce only N2. Such a metabolism could have existed on early earth, and has implications in controlling N2O and NO emissions both from natural and manmade ecosystems, where anammox bacteria contribute significantly to N2 release to the atmosphere.
2019-02-26 | PXD011763 | Pride
Project description:Roothans et al., analyzed heterotrophic denitrification processes that can be an important source of nitrous oxide. We employed planktonic nitrification-inhibited denitrifying enrichment cultures under alternating oxic-anoxic conditions. The dynamic conditions resulted in a general presence of the denitrifying enzymes. Overall, we show that aerobic denitrification should not be neglected as an ecologically relevant process. Contact author: m.laureni@tudelft.nl
2024-07-17 | PXD042057 | Pride
Project description:Ammonium is a waste product that inhibits cell growth, recombinant protein production, and protein glycosylation in mammalian cell culture. Recent studies have demonstrated that ammonium adversely affects glycosylation-related gene expression in Chinese hamster ovary (CHO) cells. However, since the CHO cell line species has not been fully sequenced, a glycosylation transcriptome analysis is not possible in this cell line. Therefore, to further understand the effects of ammonium on glycosylation-related gene expression, NS0 cells, a mouse myeloma cell line, were cultured under elevated ammonium. NS0 cells are similar to CHO cells, in that the NS0 cells are anchorage-independent and commonly used to commercially produce recombinant proteins. Additionally, DNA microarrays containing all known mouse glycosylation-related genes were available to be used to examine gene expression. NS0 cells were cultured under normal (control), elevated ammonium, elevated salt, and elevated ammonium with proline. It was observed that the control and treatments culture growth rates were not significantly different; however, the final cell densities were significantly different. The DNA microarray data was analyzed using a Welch ANOVA test with a Benjamini and Hochberg false discovery rate correction for the multiple comparisons of the glycosylation-genes. No significant difference in gene expression levels between the four conditions examined were observed. The results of this study demonstrated that NS0 cells, at the gene expression level, are insensitive to ammonium. Thus, the decreased glycosylation observed in NS0 cell cultures at elevated ammonium is likely due to changes in synthesis and degradation enzyme activity. In contrast, CHO cells have decreased glycosylation levels due to decreased sialytransferase gene expression and not increased degradation enzyme activity. Therefore, even though NS0 and CHO cells are both commonly used recombinant hosts for glycoprotein synthesis, it appears that NS0 and CHO cells had different control mechanisms respect to glycosylation-related gene expression under elevated ammonium.
2009-08-05 | GSE17495 | GEO
Project description:Salt marshes provide many key ecosystem services that have tremendous ecological and economic value. One critical service is the removal of fixed nitrogen from coastal waters, which limits the negative effects of eutrophication resulting from increased nutrient supply. Nutrient enrichment of salt marsh sediments results in higher rates of nitrogen cycling and, commonly, a concurrent increase in the flux of nitrous oxide, an important greenhouse gas. Little is known, however, regarding controls on the microbial communities that contribute to nitrous oxide fluxes in marsh sediments. To address this disconnect, we generated microbial community profiles as well as directly assayed nitrogen cycling genes that encode the enzymes responsible for overall nitrous oxide flux from salt marsh sediments. We hypothesized that communities of microbes responsible for nitrogen transformations will be structured by nitrogen availability. Taxa that respond positively to high nitrogen inputs may be responsible for the elevated rates of nitrogen cycling processes measured in fertilized sediments. Our data show that, with the exception of ammonia-oxidizing archaea, the community composition of organisms responsible for production and consumption of nitrous oxide was altered under nutrient enrichment. These results suggest that elevated rates of nitrous oxide production and consumption are the result of changes in community structure, not simply changes in microbial activity.
2018-01-13 | GSE108888 | GEO
Project description:Ammonium is a waste product that inhibits cell growth, recombinant protein production, and protein glycosylation in mammalian cell culture. Recent studies have demonstrated that ammonium adversely affects glycosylation-related gene expression in Chinese hamster ovary (CHO) cells. However, since the CHO cell line species has not been fully sequenced, a glycosylation transcriptome analysis is not possible in this cell line. Therefore, to further understand the effects of ammonium on glycosylation-related gene expression, NS0 cells, a mouse myeloma cell line, were cultured under elevated ammonium. NS0 cells are similar to CHO cells, in that the NS0 cells are anchorage-independent and commonly used to commercially produce recombinant proteins. Additionally, DNA microarrays containing all known mouse glycosylation-related genes were available to be used to examine gene expression. NS0 cells were cultured under normal (control), elevated ammonium, elevated salt, and elevated ammonium with proline. It was observed that the control and treatments culture growth rates were not significantly different; however, the final cell densities were significantly different. The DNA microarray data was analyzed using a Welch ANOVA test with a Benjamini and Hochberg false discovery rate correction for the multiple comparisons of the glycosylation-genes. No significant difference in gene expression levels between the four conditions examined were observed. The results of this study demonstrated that NS0 cells, at the gene expression level, are insensitive to ammonium. Thus, the decreased glycosylation observed in NS0 cell cultures at elevated ammonium is likely due to changes in synthesis and degradation enzyme activity. In contrast, CHO cells have decreased glycosylation levels due to decreased sialytransferase gene expression and not increased degradation enzyme activity. Therefore, even though NS0 and CHO cells are both commonly used recombinant hosts for glycoprotein synthesis, it appears that NS0 and CHO cells had different control mechanisms respect to glycosylation-related gene expression under elevated ammonium. NS0 cells (ECACC#85110503), originally from the European Collection of Cell Culture, were donated to Clemson University by Merck, Inc. NS0 cells are a mouse myeloma cell line with lymphoblast morphology, non-secreting clone, and cholesterol auxotroph. NS0 cells cultured under four conditions were examined: Control (C), Ammonium-Stressed (A), Salt-Stressed (S), and Ammonium-Stressed with Proline added to mitigate the negative effects of ammonium (P). Triplicates of each condition were used. The cultures were be monitored during the normal batch growth phase. To identify genes sensitive to ammonium in growing cultures, the 90-h time point was selected for RNA isolation and gene expression analysis. Other culture parameters that were monitored include: Cell density, viability, and glucose.
2010-05-15 | E-GEOD-17495 | biostudies-arrayexpress
Project description:Oxygen deficient zones (ODZs) are major sites of net natural oceanic nitrous oxide (N2O) production and emissions. In order to understand changes in the magnitude of N2O production in response to global change, knowledge on the individual contributions of the major microbial pathways (nitrification and denitrification) to N2O production and their regulation is needed. In the ODZ of the coastal area off Peru, the sensitivity of N2O production to oxygen and organic matter was investigated using 15N-tracer experiments in combination with qPCR and microarray analysis of total and active functional genes targeting archaeal amoA and nirS as marker genes for nitrification and denitrification, respectively. Denitrification was responsible for the highest N2O production with mean 8.7 nmol L-1 d-1 but up to 118 ± 27.8 nmol L-1 d-1 just below the oxic-anoxic interface. Highest N2O production from AO of 0.16 ± 0.003 nmol L-1 d-1 occurred in the upper oxycline at O2 concentrations of 10 - 30 µmol L-1 which coincided with highest archaeal amoA transcripts/genes. Oxygen responses of N2O production varied with substrate, but production and yields were generally highest below 10 µmol L-1 O2. Particulate organic matter additions increased N2O production by denitrification up to 5-fold suggesting increased N2O production during times of high particulate organic matter export. High N2O yields from ammonium oxidation of 2.1% were measured, but the overall contribution to N2O production stays an order of magnitude behind denitrification as an N2O source. Hence, these findings show that denitrification is the most important N2O production process in low oxygen conditions fueled by organic carbon supply which implies a positive feedback of the total oceanic N2O sources in response to increasing oceanic deoxygenation. [SUBMITTER_CITATION]: Frey, C., Bange, H. W., Achterberg, E. P., Jayakumar, A., Löscher, C. R., Arévalo-Martínez, D. L., León-Palmero, E., Sun, M., Sun, X., Xie, R. C., Oleynik, S., and Ward, B. B.: Regulation of nitrous oxide production in low-oxygen waters off the coast of Peru, Biogeosciences, 17, 2263-2287
2020-01-07 | GSE142804 | GEO
Project description:Oxygen deficient zones (ODZs) are major sites of net natural oceanic nitrous oxide (N2O) production and emissions. In order to understand changes in the magnitude of N2O production in response to global change, knowledge on the individual contributions of the major microbial pathways (nitrification and denitrification) to N2O production and their regulation is needed. In the ODZ of the coastal area off Peru, the sensitivity of N2O production to oxygen and organic matter was investigated using 15N-tracer experiments in combination with qPCR and microarray analysis of total and active functional genes targeting archaeal amoA and nirS as marker genes for nitrification and denitrification, respectively. Denitrification was responsible for the highest N2O production with mean 8.7 nmol L-1 d-1 but up to 118 ± 27.8 nmol L-1 d-1 just below the oxic-anoxic interface. Highest N2O production from AO of 0.16 ± 0.003 nmol L-1 d-1 occurred in the upper oxycline at O2 concentrations of 10 - 30 µmol L-1 which coincided with highest archaeal amoA transcripts/genes. Oxygen responses of N2O production varied with substrate, but production and yields were generally highest below 10 µmol L-1 O2. Particulate organic matter additions increased N2O production by denitrification up to 5-fold suggesting increased N2O production during times of high particulate organic matter export. High N2O yields from ammonium oxidation of 2.1% were measured, but the overall contribution to N2O production stays an order of magnitude behind denitrification as an N2O source. Hence, these findings show that denitrification is the most important N2O production process in low oxygen conditions fueled by organic carbon supply which implies a positive feedback of the total oceanic N2O sources in response to increasing oceanic deoxygenation. [SUBMITTER_CITATION]: Frey, C., Bange, H. W., Achterberg, E. P., Jayakumar, A., Löscher, C. R., Arévalo-Martínez, D. L., León-Palmero, E., Sun, M., Sun, X., Xie, R. C., Oleynik, S., and Ward, B. B.: Regulation of nitrous oxide production in low-oxygen waters off the coast of Peru, Biogeosciences, 17, 2263-2287
2020-01-07 | GSE142805 | GEO
Project description:Anaerobic ammonium-oxidising (anammox) bacteria, members of the ‘Candidatus Brocadiaceae’ family, play an important role in the nitrogen cycle and are estimated to be responsible for about half of the oceanic nitrogen loss to the atmosphere. Anammox bacteria combine ammonium with nitrite and produce dinitrogen gas via the intermediates nitric oxide and hydrazine (anammox reaction) while nitrate is formed as a by-product. These reactions take place in a specialized, membrane-bound compartment called the anammoxosome. Therefore, the substrates ammonium, nitrite and product nitrate have to cross the outer-, cytoplasmic- and anammoxosome membranes to enter or exit the anammoxosome. The genomes of all anammox species harbour multiple copies of ammonium-, nitrite- and nitrate transporter genes. Here we investigated how the distinct genes for ammonium-, nitrite- and nitrate- transport were expressed during substrate limitation in membrane bioreactors. Transcriptome analysis of Kuenenia stuttgartiensis planktonic cells under ammonium-limitation showed that three of the seven ammonium transporter genes and one of the six nitrite transporter genes were significantly upregulated, while another ammonium and nitrite transporter gene were downregulated in nitrite limited growth conditions. The two nitrate transporters were expressed to similar levels in both conditions. In addition, genes encoding enzymes involved in the anammox reaction were differentially expressed, with those using nitrite as a substrate being upregulated under nitrite limited growth and those using ammonium as a substrate being upregulated during ammonium limitation. Taken together, these results give a first insight in the potential role of the multiple nutrient transporters in regulating transport of substrates and products in and out of the compartmentalized anammox cell.
2020-06-05 | GSE148825 | GEO
Project description:Bradyrhizobium japonicum RegSR regulatory proteins belong to the family of two-component regulatory systems, and orthologs are present in many Proteobacteria where they globally control gene expression mostly in a redox-responsive manner. In this work, we have performed a transcriptional profiling of wild-type and regR mutant cells grown under anoxic denitrifying conditions. The comparative analyses of wild-type and regR strains revealed that almost 620 genes induced in the wild type under denitrifying conditions were regulated (directly or indirectly) by RegR, pointing out the important role of this protein as a global regulator of denitrification. Genes controlled by RegR included nor and nos structural genes encoding nitric oxide and nitrous oxide reductase, respectively, genes encoding electron transport proteins such as cycA (blr7544), or cy2 (bll2388), genes involved in nitric oxide detoxification (blr2806-09), copper homeostasis (copCAB), as well as two regulatory genes (bll3466, bll4130). Purified RegR interacted with the promoters of norC (blr3214), nosR (blr0314), a fixK-like gene (bll3466), and bll4130 which encodes a LysR-type regulator. By using fluorescently labeled oligonucleotide extension (FLOE), we were able to identify two transcriptional start sites located at about 35 (P1) and 22 (P2) bp upstream of the putative translational start codon of norC. P1 matched with the previously mapped 5M-bM-^@M-^Yend of norC mRNA which we demonstrate in this work to be under FixK2 control. P2 is a start site modulated by RegR and specific for anoxic conditions. Moreover, qRT-PCR experiments, expression studies with a norC-lacZ fusion, and heme c-staining analyses revealed that anoxia and nitrate are required for RegR-dependent induction of nor genes, and that this control is independent of the sensor protein RegS. A total of eight Affymetrix GeneChips are included in this study. Per strain (wild-type B. japonicum 110spc4, delta regR mutant 2426) four biological replicates were processed and analyzed. Strains were grown under anoxic conditions in Bergersen minimal medium supplemented with succinate as carbon source and KNO3 as terminal electron acceptor. For comparison, a microarray expression dataset generated with B. japonicum wild-type (Hauser et al., Mol. Genet. Genomics 278:255-271, 2007) and delta regR mutant cells (Lindemann et al., J. Bacteriol. 189:8928-8943, 2007) was used.
2014-09-01 | E-GEOD-56668 | biostudies-arrayexpress