The National Astronomy Consortium (NAC)

Science.gov (United States)

Von Schill, Lyndele; Ivory, Joyce

2017-01-01

The National Astronomy Consortium (NAC) program is designed to increase the number of underrepresented minority students into STEM and STEM careers by providing unique summer research experiences followed by long-term mentoring and cohort support. Hallmarks of the NAC program include: research or internship opportunities at one of the NAC partner sites, a framework to continue research over the academic year, peer and faculty mentoring, monthly virtual hangouts, and much more. NAC students also participate in two professional travel opportunities each year: the annual NAC conference at Howard University and poster presentation at the annual AAS winter meeting following their summer internship.The National Astronomy Consortium (NAC) is a program led by the National Radio Astronomy Consortium (NRAO) and Associated Universities, Inc. (AUI), in partnership with the National Society of Black Physicist (NSBP), along with a number of minority and majority universities.

TaNAC29, a NAC transcription factor from wheat, enhances salt and drought tolerance in transgenic Arabidopsis.

Science.gov (United States)

Huang, Quanjun; Wang, Yan; Li, Bin; Chang, Junli; Chen, Mingjie; Li, Kexiu; Yang, Guangxiao; He, Guangyuan

2015-11-04

NAC (NAM, ATAF, and CUC) transcription factors play important roles in plant biological processes, including phytohormone homeostasis, plant development, and in responses to various environmental stresses. TaNAC29 was introduced into Arabidopsis using the Agrobacterium tumefaciens-mediated floral dipping method. TaNAC29-overexpression plants were subjected to salt and drought stresses for examining gene functions. To investigate tolerant mechanisms involved in the salt and drought responses, expression of related marker genes analyses were conducted, and related physiological indices were also measured. Expressions of genes were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). A novel NAC transcription factor gene, designated TaNAC29, was isolated from bread wheat (Triticum aestivum). Sequence alignment suggested that TaNAC29 might be located on chromosome 2BS. TaNAC29 was localized to the nucleus in wheat protoplasts, and proved to have transcriptional activation activities in yeast. TaNAC29 was expressed at a higher level in the leaves, and expression levels were much higher in senescent leaves, indicating that TaNAC29 might be involved in the senescence process. TaNAC29 transcripts were increased following treatments with salt, PEG6000, H2O2, and abscisic acid (ABA). To examine TaNAC29 function, transgenic Arabidopsis plants overexpressing TaNAC29 were generated. Germination and root length assays of transgenic plants demonstrated that TaNAC29 overexpression plants had enhanced tolerances to high salinity and dehydration, and exhibited an ABA-hypersensitive response. When grown in the greenhouse, TaNAC29-overexpression plants showed the same tolerance response to salt and drought stresses at both the vegetative and reproductive period, and had delayed bolting and flowering in the reproductive period. Moreover, TaNAC29 overexpression plants accumulated lesser malondialdehyde (MDA), H2O2, while had higher superoxide dismutase (SOD) and

Ectopic Expression of Pumpkin NAC Transcription Factor CmNAC1 Improves Multiple Abiotic Stress Tolerance in Arabidopsis

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Haishun Cao

2017-11-01

Full Text Available Drought, cold and salinity are the major environmental stresses that limit agricultural productivity. NAC transcription factors regulate the stress response in plants. Pumpkin (Cucurbita moschata is an important cucurbit vegetable crop and it has strong resistance to abiotic stress; however, the biological functions of stress-related NAC genes in this crop are largely unknown. This study reports the function of CmNAC1, a stress-responsive pumpkin NAC domain protein. The CmNAC1-GFP fusion protein was transiently expressed in tobacco leaves for subcellular localization analysis, and we found that CmNAC1 is localized in the nucleus. Transactivation assay in yeast cells revealed that CmNAC1 functions as a transcription activator, and its transactivation domain is located in the C-terminus. CmNAC1 was ubiquitously expressed in different organs, and its transcript was induced by salinity, cold, dehydration, H2O2, and abscisic acid (ABA treatment. Furthermore, the ectopic expression (EE of CmNAC1 in Arabidopsis led to ABA hypersensitivity and enhanced tolerance to salinity, drought and cold stress. In addition, five ABA-responsive elements were enriched in CmNAC1 promoter. The CmNAC1-EE plants exhibited different root architecture, leaf morphology, and significantly high concentration of ABA compared with WT Arabidopsis under normal conditions. Our results indicated that CmNAC1 is a critical factor in ABA signaling pathways and it can be utilized in transgenic breeding to improve the abiotic stress tolerance of crops.

O-GlcNAc site-mapping of liver X receptor-α and O-GlcNAc transferase.

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Fan, Qiong; Moen, Anders; Anonsen, Jan Haug; Bindesbøll, Christian; Sæther, Thomas; Carlson, Cathrine Rein; Grønning-Wang, Line M

2018-05-05

The Liver X Receptor α (LXRα) belongs to the nuclear receptor superfamily and plays an essential role in regulating cholesterol, lipid and glucose metabolism and inflammatory responses. We have previously shown that LXRα is post-translationally modified by O-linked β-N-acetyl-glucosamine (O-GlcNAc) with increased transcriptional activity. Moreover, we showed that LXRα associates with O-GlcNAc transferase (OGT) in vitro and in vivo in mouse liver. In this study, we report that human LXRα is O-GlcNAc modified in its N-terminal domain (NTD) by identifying a specific O-GlcNAc site S49 and a novel O-GlcNAc modified peptide 20 LWKPGAQDASSQAQGGSSCILRE 42 . However, O-GlcNAc site-mutations did not modulate LXRα transactivation of selected target gene promoters in vitro. Peptide array and co-immunoprecipitation assays demonstrate that LXRα interacts with OGT in its NTD and ligand-binding domain (LBD) in a ligand-independent fashion. Moreover, we map two new O-GlcNAc sites in the longest OGT isoform (ncOGT): S437 in the tetratricopeptide repeat (TPR) 13 domain and T1043 in the far C-terminus, and a new O-GlcNAc modified peptide (amino acids 826-832) in the intervening region (Int-D) within the catalytic domain. We also map four new O-GlcNAc sites in the short isoform sOGT: S391, T393, S399 and S437 in the TPRs 11-13 domain. Future studies will reveal the biological role of identified O-GlcNAc sites in LXRα and OGT. Copyright © 2018 Elsevier Inc. All rights reserved.

ThNAC13, a NAC Transcription Factor from Tamarix hispida, Confers Salt and Osmotic Stress Tolerance to Transgenic Tamarix and Arabidopsis

OpenAIRE

Wang, Liuqiang; Li, Zhen; Lu, Mengzhu; Wang, Yucheng

2017-01-01

NAC (NAM, ATAF1/2, and CUC2) proteins play critical roles in many plant biological processes and environmental stress. However, NAC proteins from Tamarix hispida have not been functionally characterized. Here, we studied a NAC gene from T. hispida, ThNAC13, in response to salt and osmotic stresses. ThNAC13 is a nuclear protein with a C-terminal transactivation domain. ThNAC13 can bind to NAC recognized sites and calmodulin-binding NAC (CBNAC) binding element. Overexpression of ThNAC13 in Arab...

NAC transcription factors: structurally distinct, functionally diverse

DEFF Research Database (Denmark)

Olsen, Addie Nina; Ernst, Heidi A; Leggio, Leila Lo

2005-01-01

level and localization, and to the first indications of NAC participation in transcription factor networks. The recent determination of the DNA and protein binding NAC domain structure offers insight into the molecular functions of the protein family. Research into NAC transcription factors has......NAC proteins constitute one of the largest families of plant-specific transcription factors, and the family is present in a wide range of land plants. Here, we summarize the biological and molecular functions of the NAC family, paying particular attention to the intricate regulation of NAC protein...

Characterization of a chickpea (Cicer arietinum L.) NAC family gene, CarNAC5, which is both developmentally- and stress-regulated.

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Peng, Hui; Cheng, Hui-Ying; Yu, Xin-Wang; Shi, Qing-Hua; Zhang, Hua; Li, Jian-Gui; Ma, Hao

2009-01-01

It has been documented that the plant-specific NAC (for NAM, ATAF1,2 and CUC2) transcription factors play an important role in plant development and stress responses. In this study, a chickpea NAC gene CarNAC5 (for Cicer arietinum L. NAC gene 5) was isolated from a cDNA library from chickpea leaves treated by polyethylene glycol (PEG). CarNAC5, as a single/low copy gene, contained three exons and two introns within genomic DNA sequence and encoded a polypeptide with 291 amino acids. CarNAC5 protein had a conserved NAC domain in the N-terminus and showed high similarity to other NACs, especially ATAF subgroup members. The CarNAC5:GFP fusion protein was localized in the nucleus of onion epidermal cells. Furthermore, CarNAC5 protein activated the reporter genes LacZ and HIS3 in yeast. The transactivation activity was mapped to the C-terminal region. The transcripts of CarNAC5 appeared in many chickpea tissues including seedling leaves, stems, roots, flowers, seeds and pods, but mostly accumulated in flowers. Meanwhile, CarNAC5 was strongly expressed during seed maturation and in embryos of the early germinating seeds. It was also significantly induced by drought, heat, wounding, salicylic acid (SA), and indole-3-acetic acid (IAA) treatments. Our results suggest that CarNAC5 encodes a novel NAC-domain protein and acts as a transcriptional activator involved in plant developmental regulation and various stress responses.

ThNAC13, a NAC Transcription Factor from Tamarix hispida, Confers Salt and Osmotic Stress Tolerance to Transgenic Tamarix and Arabidopsis

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Wang, Liuqiang; Li, Zhen; Lu, Mengzhu; Wang, Yucheng

2017-01-01

NAC (NAM, ATAF1/2, and CUC2) proteins play critical roles in many plant biological processes and environmental stress. However, NAC proteins from Tamarix hispida have not been functionally characterized. Here, we studied a NAC gene from T. hispida, ThNAC13, in response to salt and osmotic stresses. ThNAC13 is a nuclear protein with a C-terminal transactivation domain. ThNAC13 can bind to NAC recognized sites and calmodulin-binding NAC (CBNAC) binding element. Overexpression of ThNAC13 in Arabidopsis improved seed germination rate and increased root growth and fresh weight gain under salt or osmotic stress. Transgenic T. hispida plants transiently overexpressing ThNAC13 and with RNAi-silenced ThNAC13 were generated for gain- and loss-of-function experiments. Following exposure to salt or osmotic stress, overexpression of ThNAC13 induced superoxide dismutase (SOD) and peroxidase (POD) activities, chlorophyll and proline contents; decreased the reactive oxygen species (ROS) and malondialdehyde levels; and reduced electrolyte leakage rates in both transgenic Tamarix and Arabidopsis plants. In contrast, RNAi-silenced ThNAC13 showed the opposite results in transgenic Tamarix. Furthermore, ThNAC13 induced the expression of SODs and PODs in transgenic Arabidopsis. These results suggest that ThNAC13 improves salt and osmotic tolerance by enhancing the ROS-scavenging capability and adjusting osmotic potential. PMID:28491072

ThNAC13, a NAC Transcription Factor from Tamarix hispida, Confers Salt and Osmotic Stress Tolerance to Transgenic Tamarix and Arabidopsis

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Mengzhu Lu

2017-04-01

Full Text Available NAC (NAM, ATAF1/2, and CUC2 proteins play critical roles in many plant biological processes and environmental stress. However, NAC proteins from Tamarix hispida have not been functionally characterized. Here, we studied a NAC gene from T. hispida, ThNAC13, in response to salt and osmotic stresses. ThNAC13 is a nuclear protein with a C-terminal transactivation domain. ThNAC13 can bind to NAC recognized sites and calmodulin-binding NAC (CBNAC binding element. Overexpression of ThNAC13 in Arabidopsis improved seed germination rate and increased root growth and fresh weight gain under salt or osmotic stress. Transgenic T. hispida plants transiently overexpressing ThNAC13 and with RNAi-silenced ThNAC13 were generated for gain- and loss-of-function experiments. Following exposure to salt or osmotic stress, overexpression of ThNAC13 induced superoxide dismutase (SOD and peroxidase (POD activities, chlorophyll and proline contents; decreased the reactive oxygen species (ROS and malondialdehyde levels; and reduced electrolyte leakage rates in both transgenic Tamarix and Arabidopsis plants. In contrast, RNAi-silenced ThNAC13 showed the opposite results in transgenic Tamarix. Furthermore, ThNAC13 induced the expression of SODs and PODs in transgenic Arabidopsis. These results suggest that ThNAC13 improves salt and osmotic tolerance by enhancing the ROS-scavenging capability and adjusting osmotic potential.

Treatment of reactive process wastewater with high-level ammonia by blow-off method

International Nuclear Information System (INIS)

Chen Xiaotong; Quan Ying; Wang Yang; Fu Genna; Liu Bing; Tang Yaping

2012-01-01

The ceramic UO 2 kernels for nuclear fuel elements of high temperature gas cooled reactors were prepared through sol-gel process with uranyl nitrate, which produces process wastewater containing high-level ammonia and uranium. The blow-off method on a bench scale was investigated to remove ammonia from reactive wastewater. Under the optimized operating conditions, the ammonia can be removed by more than 95%, with little reactive uranium distilled. The effects of pH, heating temperature and stripping time were studied. Static tests with ion-exchange resin indicate that ammonia removal treatment increases uranium accumulation in anion exchange resin. (authors)

A Conserved Splicing Silencer Dynamically Regulates O-GlcNAc Transferase Intron Retention and O-GlcNAc Homeostasis

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Sung-Kyun Park

2017-08-01

Full Text Available Modification of nucleocytoplasmic proteins with O-GlcNAc regulates a wide variety of cellular processes and has been linked to human diseases. The enzymes O-GlcNAc transferase (OGT and O-GlcNAcase (OGA add and remove O-GlcNAc, but the mechanisms regulating their expression remain unclear. Here, we demonstrate that retention of the fourth intron of OGT is regulated in response to O-GlcNAc levels. We further define a conserved intronic splicing silencer (ISS that is necessary for OGT intron retention. Deletion of the ISS in colon cancer cells leads to increases in OGT, but O-GlcNAc homeostasis is maintained by concomitant increases in OGA protein. However, the ISS-deleted cells are hypersensitive to OGA inhibition in culture and in soft agar. Moreover, growth of xenograft tumors from ISS-deleted cells is compromised in mice treated with an OGA inhibitor. Thus, ISS-mediated regulation of OGT intron retention is a key component in OGT expression and maintaining O-GlcNAc homeostasis.

A NAC transcription factor gene of Chickpea (Cicer arietinum), CarNAC3, is involved in drought stress response and various developmental processes.

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Peng, Hui; Cheng, Hui-Ying; Chen, Chen; Yu, Xin-Wang; Yang, Jia-Ni; Gao, Wen-Rui; Shi, Qing-Hua; Zhang, Hua; Li, Jian-Gui; Ma, Hao

2009-11-15

NAC transcription factors have been found to play important roles in plant development and responses to environmental stresses. Based on two cDNA libraries constructed from the PEG-treated and -nontreated seedling leaves of chickpea, a NAC gene, CarNAC3, was isolated and characterized. The results indicated that CarNAC3 contained 285 amino acids and had a conserved NAC domain. It was localized in the nucleus and possessed trans-activation activity in the C-terminus. Phylogenetic analysis showed that CarNAC3 belonged to the NAP (NAC-like, activated by APETALA3/PISTILLATA) subgroup of the NAC protein family. CarNAC3 exhibited organ-specific expression and its induction was strongly dependent on leaf age. CarNAC3 showed differential expression patterns during seed development and germination, and could be significantly induced by drought stress, abscisic acid (ABA), ethephon (Et) and indole-3-acetic acid (IAA), but was inhibited by N-6-benzyl-adenine (6-BA). Our data suggest that CarNAC3 may be a transcriptional activator involved in drought stress response and various developmental processes.

Update on NAC's transportation projects

International Nuclear Information System (INIS)

Anne, Catherine; Patterson, John

2005-01-01

The Global Threat Reduction Initiative (GTRI) was announced in early 2004 by then U.S. Secretary of Energy Spencer Abraham and was reinforced by an international meeting in Vienna in September 2004 of countries supporting non- proliferation efforts. Under GTRI, the Foreign Research Reactor Program (FRR) will continue and irradiated fuel shipments under the Russian Research Fuel Return Program (RRRFR) will begin. These programs will result in a projected increase in research reactor shipments in the coming years. NAC owns and operates a fleet of eight NAC-LWT casks, which can transport up to 42 MTR fuel elements each. For the past 30 years, NAC has been supporting the Department of Energy with non-proliferation initiatives. Our teams have loaded casks in more than 25 foreign countries. Recent incidents of terrorism and ongoing threats have confirmed the necessity to ensure the security of high-enriched uranium and remove it from sensitive locations. Tremendous government efforts were initiated in 2004 in order to execute intra-governmental agreements for reactor conversion and material removal. As a result of these agreements, NAC will continue to provide its cask lease and transportation services to the Department of Energy. We expect to see very challenging shipments in the coming years. We are committed to these non-proliferation efforts as well as meeting our commercial customers' needs for transportation of irradiated fuel. The recent acquisition of NAC by USEC Inc. strengthens NAC's resources and joins NAC with a corporation with a strong non-proliferation orientation as the U.S. Government's Executive Agent under the highly successful U.S.-Russian Megatons to Megawatts program. This presentation summarizes our planned activities for the coming years with respect to GTRI initiatives. (author)

O-GlcNAc-specific antibody CTD110.6 cross-reacts with N-GlcNAc2-modified proteins induced under glucose deprivation.

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Takahiro Isono

Full Text Available Modification of serine and threonine residues in proteins by O-linked β-N-acetylglucosamine (O-GlcNAc glycosylation is a feature of many cellular responses to the nutritional state and to stress. O-GlcNAc modification is reversibly regulated by O-linked β-N-acetylglucosamine transferase (OGT and β-D-N-acetylglucosaminase (O-GlcNAcase. O-GlcNAc modification of proteins is dependent on the concentration of uridine 5'-diphospho-N-acetylglucosamine (UDP-GlcNAc, which is a substrate of OGT and is synthesized via the hexosamine biosynthetic pathway. Immunoblot analysis using the O-GlcNAc-specific antibody CTD110.6 has indicated that glucose deprivation increases protein O-GlcNAcylation in some cancer cells. The mechanism of this paradoxical phenomenon has remained unclear. Here we show that the increased glycosylation induced by glucose deprivation and detected by CTD110.6 antibodies is actually modification by N-GlcNAc(2, rather than by O-GlcNAc. We found that this induced glycosylation was not regulated by OGT and O-GlcNAcase, unlike typical O-GlcNAcylation, and it was inhibited by treatment with tunicamycin, an N-glycosylation inhibitor. Proteomics analysis showed that proteins modified by this induced glycosylation were N-GlcNAc(2-modified glycoproteins. Furthermore, CTD110.6 antibodies reacted with N-GlcNAc(2-modified glycoproteins produced by a yeast strain with a ts-mutant of ALG1 that could not add a mannose residue to dolichol-PP-GlcNAc(2. Our results demonstrated that N-GlcNAc(2-modified glycoproteins were induced under glucose deprivation and that they cross-reacted with the O-GlcNAc-specific antibody CTD110.6. We therefore propose that the glycosylation status of proteins previously classified as O-GlcNAc-modified proteins according to their reactivity with CTD110.6 antibodies must be re-examined. We also suggest that the repression of mature N-linked glycoproteins due to increased levels of N-GlcNAc(2-modified proteins is a newly

Molecular cloning and characterization of a membrane associated NAC family gene, SiNAC from foxtail millet [Setaria italica (L.) P. Beauv].

Science.gov (United States)

Puranik, Swati; Bahadur, Ranjit Prasad; Srivastava, Prem S; Prasad, Manoj

2011-10-01

The plant-specific NAC (NAM, ATAF, and CUC) transcription factors have diverse role in development and stress regulation. A transcript encoding NAC protein, termed SiNAC was identified from a salt stress subtractive cDNA library of S. italica seedling (Puranik et al., J Plant Physiol 168:280-287, 2011). This single/low copy gene containing four exons and four introns within the genomic-sequence encoded a protein of 462 amino acids. Structural analysis revealed that highly divergent C terminus contains a transmembrane domain. The NAC domain consisted of a twisted antiparallel beta-sheet packing against N terminal alpha helix on one side and a shorter helix on the other side. The domain was predicted to homodimerize and control DNA-binding specificity. The physicochemical features of the SiNAC homodimer interface justified the dimeric form of the predicted model. A 1539 bp fragment upstream to the start codon of SiNAC gene was cloned and in silico analysis revealed several putative cis-acting regulatory elements within the promoter sequence. Transactivation analysis indicated that SiNAC activated expression of reporter gene and the activation domain lied at the C terminal. The SiNAC:GFP was detected in the nucleus and cytoplasm while SiNAC ΔC(1-158):GFP was nuclear localized in onion epidermal cells. SiNAC transcripts mostly accumulated in young spikes and were strongly induced by dehydration, salinity, ethephon, and methyl jasmonate. These results suggest that SiNAC encodes a membrane associated NAC-domain protein that may function as a transcriptional activator in response to stress and developmental regulation in plants.

Banana NAC transcription factor MusaNAC042 is positively associated with drought and salinity tolerance.

Science.gov (United States)

Tak, Himanshu; Negi, Sanjana; Ganapathi, T R

2017-03-01

Banana is an important fruit crop and its yield is hampered by multiple abiotic stress conditions encountered during its growth. The NAC (NAM, ATAF, and CUC) transcription factors are involved in plant response to biotic and abiotic stresses. In the present study, we studied the induction of banana NAC042 transcription factor in drought and high salinity conditions and its overexpression in transgenic banana to improve drought and salinity tolerance. MusaNAC042 expression was positively associated with stress conditions like salinity and drought and it encoded a nuclear localized protein. Transgenic lines of banana cultivar Rasthali overexpressing MusaNAC042 were generated by Agrobacterium-mediated transformation of banana embryogenic cells and T-DNA insertion was confirmed by PCR and Southern blot analysis. Our results using leaf disc assay indicated that transgenic banana lines were able to tolerate drought and high salinity stress better than the control plants and retained higher level of total chlorophyll and lower level of MDA content (malondialdehyde). Transgenic lines analyzed for salinity (250 mM NaCl) and drought (Soil gravimetric water content 0.15) tolerance showed higher proline content, better Fv/Fm ratio, and lower levels of MDA content than control suggesting that MusaNAC042 may be involved in responses to higher salinity and drought stresses in banana. Expression of several abiotic stress-related genes like those coding for CBF/DREB, LEA, and WRKY factors was altered in transgenic lines indicating that MusaNAC042 is an efficient modulator of abiotic stress response in banana.

The rose (Rosa hybrida) NAC transcription factor 3 gene, RhNAC3, involved in ABA signaling pathway both in rose and Arabidopsis.

Science.gov (United States)

Jiang, Guimei; Jiang, Xinqiang; Lü, Peitao; Liu, Jitao; Gao, Junping; Zhang, Changqing

2014-01-01

Plant transcription factors involved in stress responses are generally classified by their involvement in either the abscisic acid (ABA)-dependent or the ABA-independent regulatory pathways. A stress-associated NAC gene from rose (Rosa hybrida), RhNAC3, was previously found to increase dehydration tolerance in both rose and Arabidopsis. However, the regulatory mechanism involved in RhNAC3 action is still not fully understood. In this study, we isolated and analyzed the upstream regulatory sequence of RhNAC3 and found many stress-related cis-elements to be present in the promoter, with five ABA-responsive element (ABRE) motifs being of particular interest. Characterization of Arabidopsis thaliana plants transformed with the putative RhNAC3 promoter sequence fused to the β-glucuronidase (GUS) reporter gene revealed that RhNAC3 is expressed at high basal levels in leaf guard cells and in vascular tissues. Moreover, the ABRE motifs in the RhNAC3 promoter were observed to have a cumulative effect on the transcriptional activity of this gene both in the presence and absence of exogenous ABA. Overexpression of RhNAC3 in A. thaliana resulted in ABA hypersensitivity during seed germination and promoted leaf closure after ABA or drought treatments. Additionally, the expression of 11 ABA-responsive genes was induced to a greater degree by dehydration in the transgenic plants overexpressing RhNAC3 than control lines transformed with the vector alone. Further analysis revealed that all these genes contain NAC binding cis-elements in their promoter regions, and RhNAC3 was found to partially bind to these putative NAC recognition sites. We further found that of 219 A. thaliana genes previously shown by microarray analysis to be regulated by heterologous overexpression RhNAC3, 85 are responsive to ABA. In rose, the expression of genes downstream of the ABA-signaling pathways was also repressed in RhNAC3-silenced petals. Taken together, we propose that the rose RhNAC3 protein

The rose (Rosa hybrida NAC transcription factor 3 gene, RhNAC3, involved in ABA signaling pathway both in rose and Arabidopsis.

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Guimei Jiang

Full Text Available Plant transcription factors involved in stress responses are generally classified by their involvement in either the abscisic acid (ABA-dependent or the ABA-independent regulatory pathways. A stress-associated NAC gene from rose (Rosa hybrida, RhNAC3, was previously found to increase dehydration tolerance in both rose and Arabidopsis. However, the regulatory mechanism involved in RhNAC3 action is still not fully understood. In this study, we isolated and analyzed the upstream regulatory sequence of RhNAC3 and found many stress-related cis-elements to be present in the promoter, with five ABA-responsive element (ABRE motifs being of particular interest. Characterization of Arabidopsis thaliana plants transformed with the putative RhNAC3 promoter sequence fused to the β-glucuronidase (GUS reporter gene revealed that RhNAC3 is expressed at high basal levels in leaf guard cells and in vascular tissues. Moreover, the ABRE motifs in the RhNAC3 promoter were observed to have a cumulative effect on the transcriptional activity of this gene both in the presence and absence of exogenous ABA. Overexpression of RhNAC3 in A. thaliana resulted in ABA hypersensitivity during seed germination and promoted leaf closure after ABA or drought treatments. Additionally, the expression of 11 ABA-responsive genes was induced to a greater degree by dehydration in the transgenic plants overexpressing RhNAC3 than control lines transformed with the vector alone. Further analysis revealed that all these genes contain NAC binding cis-elements in their promoter regions, and RhNAC3 was found to partially bind to these putative NAC recognition sites. We further found that of 219 A. thaliana genes previously shown by microarray analysis to be regulated by heterologous overexpression RhNAC3, 85 are responsive to ABA. In rose, the expression of genes downstream of the ABA-signaling pathways was also repressed in RhNAC3-silenced petals. Taken together, we propose that the rose RhNAC

Chemo-enzymatic modification of poly-N-acetyllactosamine (LacNAc oligomers and N,N-diacetyllactosamine (LacDiNAc based on galactose oxidase treatment

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Christiane E. Kupper

2012-05-01

Full Text Available The importance of glycans in biological systems is highlighted by their various functions in physiological and pathological processes. Many glycan epitopes on glycoproteins and glycolipids are based on N-acetyllactosamine units (LacNAc; Galβ1,4GlcNAc and often present on extended poly-LacNAc glycans ([Galβ1,4GlcNAc]n. Poly-LacNAc itself has been identified as a binding motif of galectins, an important class of lectins with functions in immune response and tumorigenesis. Therefore, the synthesis of natural and modified poly-LacNAc glycans is of specific interest for binding studies with galectins as well as for studies of their possible therapeutic applications. We present the oxidation by galactose oxidase and subsequent chemical or enzymatic modification of terminal galactose and N-acetylgalactosamine residues of poly-N-acetyllactosamine (poly-LacNAc oligomers and N,N-diacetyllactosamine (LacDiNAc by galactose oxidase. Product formation starting from different poly-LacNAc oligomers was characterised and optimised regarding formation of the C6-aldo product. Further modification of the aldehyde containing glycans, either by chemical conversion or enzymatic elongation, was established. Base-catalysed β-elimination, coupling of biotin–hydrazide with subsequent reduction to the corresponding hydrazine linkage, and coupling by reductive amination to an amino-functionalised poly-LacNAc oligomer were performed and the products characterised by LC–MS and NMR analysis. Remarkably, elongation of terminally oxidised poly-LacNAc glycans by β3GlcNAc- and β4Gal-transferase was also successful. In this way, a set of novel, modified poly-LacNAc oligomers containing terminally and/or internally modified galactose residues were obtained, which can be used for binding studies and various other applications.

A Pervaporation Study of Ammonia Solutions Using Molecular Sieve Silica Membranes

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Xing Yang

2014-02-01

Full Text Available An innovative concept is proposed to recover ammonia from industrial wastewater using a molecular sieve silica membrane in pervaporation (PV, benchmarked against vacuum membrane distillation (VMD. Cobalt and iron doped molecular sieve silica-based ceramic membranes were evaluated based on the ammonia concentration factor downstream and long-term performance. A modified low-temperature membrane evaluation system was utilized, featuring the ability to capture and measure ammonia in the permeate. It was found that the silica membrane with confirmed molecular sieving features had higher water selectivity over ammonia. This was due to a size selectivity mechanism that favoured water, but blocked ammonia. However, a cobalt doped silica membrane previously treated with high temperature water solutions demonstrated extraordinary preference towards ammonia by achieving up to a 50,000 mg/L ammonia concentration (a reusable concentration level measured in the permeate when fed with 800 mg/L of ammonia solution. This exceeded the concentration factor expected by the benchmark VMD process by four-fold, suspected to be due to the competitive adsorption of ammonia over water into the silica structure with pores now large enough to accommodate ammonia. However, this membrane showed a gradual decline in selectivity, suspected to be due to the degradation of the silica material/pore structure after several hours of operation.

Genomic analysis of NAC transcription factors in banana (Musa acuminata) and definition of NAC orthologous groups for monocots and dicots.

Science.gov (United States)

Cenci, Albero; Guignon, Valentin; Roux, Nicolas; Rouard, Mathieu

2014-05-01

Identifying the molecular mechanisms underlying tolerance to abiotic stresses is important in crop breeding. A comprehensive understanding of the gene families associated with drought tolerance is therefore highly relevant. NAC transcription factors form a large plant-specific gene family involved in the regulation of tissue development and responses to biotic and abiotic stresses. The main goal of this study was to set up a framework of orthologous groups determined by an expert sequence comparison of NAC genes from both monocots and dicots. In order to clarify the orthologous relationships among NAC genes of different species, we performed an in-depth comparative study of four divergent taxa, in dicots and monocots, whose genomes have already been completely sequenced: Arabidopsis thaliana, Vitis vinifera, Musa acuminata and Oryza sativa. Due to independent evolution, NAC copy number is highly variable in these plant genomes. Based on an expert NAC sequence comparison, we propose forty orthologous groups of NAC sequences that were probably derived from an ancestor gene present in the most recent common ancestor of dicots and monocots. These orthologous groups provide a curated resource for large-scale protein sequence annotation of NAC transcription factors. The established orthology relationships also provide a useful reference for NAC function studies in newly sequenced genomes such as M. acuminata and other plant species.

Barley plants over-expressing the NAC transcription factor gene HvNAC005 show stunting and delay in development combined with early senescence

DEFF Research Database (Denmark)

Christiansen, Michael W; Matthewman, Colette; Podzimska-Sroka, Dagmara

2016-01-01

-expressing plants showed up-regulation of genes involved with secondary metabolism, hormone metabolism, stress, signalling, development, and transport. Up-regulation of senescence markers and hormone metabolism and signalling genes supports a role of HvNAC005 in the cross field of different hormone and signalling......The plant-specific NAC transcription factors have attracted particular attention because of their involvement in stress responses, senescence, and nutrient remobilization. The HvNAC005 gene of barley encodes a protein belonging to subgroup NAC-a6 of the NAC family. This study shows that HvNAC005...... pathways. Binding of HvNAC005 to promoter sequences of putative target genes containing the T[G/A]CGT core motif was shown by direct protein-DNA interactions of HvNAC005 with promoters for two of the up-regulated genes. In conclusion, HvNAC005 was shown to be a strong positive regulator of senescence...

A Chemoenzymatic Histology Method for O-GlcNAc Detection.

Science.gov (United States)

Aguilar, Aime Lopez; Hou, Xiaomeng; Wen, Liuqing; Wang, Peng G; Wu, Peng

2017-12-14

Modification of nuclear and cytoplasmic proteins by the addition or removal of O-GlcNAc dynamically impacts multiple biological processes. Here, we present the development of a chemoenzymatic histology method for the detection of O-GlcNAc in tissue specimens. We applied this method to screen murine organs, uncovering specific O-GlcNAc distribution patterns in different tissue structures. We then utilized our histology method for O-GlcNAc detection in human brain specimens from healthy donors and donors with Alzheimer's disease and found higher levels of O-GlcNAc in specimens from healthy donors. We also performed an analysis using a multiple cancer tissue array, uncovering different O-GlcNAc levels between healthy and cancerous tissues, as well as different O-GlcNAc cellular distributions within certain tissue specimens. This chemoenzymatic histology method therefore holds great potential for revealing the biology of O-GlcNAc in physiopathological processes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization and expression profile of CaNAC2 pepper gene

Directory of Open Access Journals (Sweden)

Wei-Li eGuo

2015-09-01

Full Text Available The plant-specific NAC (NAM, ATAF, and CUC transcription factors have diverse role in development and stress regulation. A new transcript encoding NAC protein, homologous to nam-like protein 4 from Petunia was identified from an ABA-regulated subtractive cDNA library of Capsicum annuum seedling. Here, this homolog (named CaNAC2 from Capsicum annuum was characterized and investigated its role in abiotic stress tolerance. Our results indicated that a plant-specific and conserved NAC domain was located in the N-terminus domain of CaNAC2 which was predicted to encode a polypeptide of 410 amino acids. Phylogenetic analysis showed that CaNAC2 belonged to the NAC2 subgroup of the orthologous group 4d. The protein CaNAC2 was subcellularly localized in the nucleus and it had transcriptional activity in yeast cell. CaNAC2 was expressed mainly in seed and root. The transcription expression of CaNAC2 was strongly induced by cold, salt and ABA treatment and inhibited by osmotic stress and SA treatment. Silence of CaNAC2 in virus-induced gene silenced pepper seedlings resulted in the increased susceptibility to cold stress and delayed the salt-induced leaf chlorophyll degradation. These results indicated that this novel CaNAC2 gene might be involved in pepper response to abiotic stress tolerance.

Characterization of the okra mucilage by interaction with Gal, GalNAc and GlcNAc specific lectins.

Science.gov (United States)

Wu, A M; Jiang, Y J; Hwang, P Y; Shen, F S

1995-02-23

A bio-active polysaccharide, which was the major component of the extract of the common okra, Hibiscus esculentus, was isolated from the extract by precipitation with ethanol between 28.5 to 45%. According to a previous report (Whistler, R.L. and Conrad, H.E. (1954) J. Am. Chem. Soc. 76, 1673-1674), this polysaccharide contains the Gal alpha 1-->4Gal sequence, which is the ligand for the uropathogenic Escherichia coli and toxic lectins. Analysis of the binding property of the okra polysaccharide by precipitin assay with Gal, GalNAc and GlcNAc specific lectins showed that this okra mucilage reacted best with Mistletoe toxic lectin-I (ML-I) and precipitated over 80% of the ML-I nitrogen (5.1 micrograms N) added. It also precipitated well with Abrus precatorius (APA), Momordica charantia (MCA) and Ricinus communis (RCA1) agglutinins, but poorly with other lectins. The results obtained suggest that this polysaccharide is a valuable reagent to differentiate Gal specific lectins from the GalNAc and/or GlcNAc specific series.

The Nitrate-Inducible NAC Transcription Factor TaNAC2-5A Controls Nitrate Response and Increases Wheat Yield1[OPEN

Science.gov (United States)

He, Xue; Qu, Baoyuan; Li, Wenjing; Zhao, Xueqiang; Teng, Wan; Ma, Wenying; Ren, Yongzhe; Li, Bin; Li, Zhensheng; Tong, Yiping

2015-01-01

Nitrate is a major nitrogen resource for cereal crops; thus, understanding nitrate signaling in cereal crops is valuable for engineering crops with improved nitrogen use efficiency. Although several regulators have been identified in nitrate sensing and signaling in Arabidopsis (Arabidopsis thaliana), the equivalent information in cereals is missing. Here, we isolated a nitrate-inducible and cereal-specific NAM, ATAF, and CUC (NAC) transcription factor, TaNAC2-5A, from wheat (Triticum aestivum). A chromatin immunoprecipitation assay showed that TaNAC2-5A could directly bind to the promoter regions of the genes encoding nitrate transporter and glutamine synthetase. Overexpression of TaNAC2-5A in wheat enhanced root growth and nitrate influx rate and, hence, increased the root’s ability to acquire nitrogen. Furthermore, we found that TaNAC2-5A-overexpressing transgenic wheat lines had higher grain yield and higher nitrogen accumulation in aerial parts and allocated more nitrogen in grains in a field experiment. These results suggest that TaNAC2-5A is involved in nitrate signaling and show that it is an exciting gene resource for breeding crops with more efficient use of fertilizer. PMID:26371233

Defining carbohydrate specificity of Ricinus communis agglutinin as Gal beta 1-->4GlcNAc (II) > Gal beta 1-->3GlcNAc (I) > Gal alpha 1-->3Gal (B) > Gal beta 1-->3GalNAc (T).

Science.gov (United States)

Wu, J H; Herp, A; Wu, A M

1993-03-01

To define carbohydrate specificity of Ricinus communis agglutinin (RCA1), the combining site of RCA1 was further characterized by quantitative precipitin (QPA) and precipitin-inhibition assays (QPIA). Among the oligosaccharides tested for QPIA, Gal beta 1-->4GlcNAc (II, human blood group type II precursor sequence) was found to be 7.1 times more active than Gal beta 1-->3GalNAc (T, Thomsen-Friedenreich sequence) and about 1.7 times more active than the other three disaccharides tested--Gal beta 1-->4Man, Gal beta 1-->3DAra and Gal beta 1-->6GalNAc. Gal alpha 1-->4Gal, the receptor of the uropathogenic E. coli ligand was 3.6 times less active than the II sequence. These results indicate that the beta 1-->4 linkage of the terminal Gal to subterminal GlcNAc is important as this beta 1-->4GlcNAc sequence is at least 1.6 times more active than other types of disaccharides. Among the glycoproteins examined for QPA, native and desialized bovine submandibular glycoproteins, native and desialized human plasma alpha 1-acid glycoproteins, as well as crude hog stomach mucin and its three mild acid hydrolyzed products reacted well with the lectin. These glycoproteins precipitated over 75% of the lectin nitrogen added indicating that RCA1 has the ability to recognize Gal beta 1-->4/3GlcNAc and/or the related residues at the non-reducing ends and at positions in the interior of the chains. However, Tn (GalNAc alpha 1-->Ser/Thr sequence) rich glycoproteins such as desialized ovine submandibular glycoprotein and desialized armadillo salivary glycoprotein, in which over 90% of the carbohydrate side chains are Tn determinants with none or only a trace of I/II or T determinants, precipitated poorly with RCA1. From the present and previous results obtained, the carbohydrate specificity of RCA1 can be constructed and summarized in decreasing order by lectin determinants as follows: II (Gal beta 1-->4GlcNAc) > I (Gal beta 1-->3GlcNAc) > E (Gal alpha 1-->4Gal) and B (Gal alpha 1-->3Gal

Studies on the use of supercritical ammonia for ceramic nitride synthesis and fabrication

Science.gov (United States)

Cornell, Linda; Lin, Y. C.; Philipp, Warren H.

1990-01-01

The extractability of ammonia halides (including ammonium thiocyanate) formed as byproducts from the synthesis of Si(NH)2 via ammonolysis of the corresponding silicon tetrahalides using supercritical NH3 as the extraction medium was investigated. It was found that the NH4SCN byproduct of ammonolysis of Si(SCN)4 can be almost completely extracted from the insoluble Si(NH)2 forming a promising system for the synthesis of pure Si(NH)2, one of the best precursors for Si3N4. In addition it was found that Si3N4, AlN, BN, and Si(NH)2 are insoluble in SC ammonia. Also discussed are design considerations for a supercritical ammonia extraction unit.

O-GlcNAc modification: why so intimately associated with phosphorylation?

Directory of Open Access Journals (Sweden)

Ande Sudharsana R

2011-01-01

Full Text Available Abstract Post-translational modification of proteins at serine and threonine side chains by β-N-acetylglucosamine (O-GlcNAc mediated by the enzyme β-N-acetylglucosamine transferase has been emerging as a fundamental regulatory mechanism encompassing a wide range of proteins involved in cell division, metabolism, transcription and cell signaling. Furthermore, an extensive interplay between O-GlcNAc modification and serine/threonine phosphorylation in a variety of proteins has been reported to exist. However, our understanding of the regulatory mechanisms involved in O-GlcNAc modification and its interplay with serine/threonine phosphorylation in proteins is still elusive. Recent success in the mapping of O-GlcNAc modification sites in proteins as a result of technological advancement in mass spectrometry have revealed two important clues which may be inherently connected to the regulation of O-GlcNAc modification and its interplay with phosphorylation in proteins. First, almost all O-GlcNAc modified proteins are known phospho proteins. Second, the prevalence of tyrosine phosphorylation among O-GlcNAc modified proteins is exceptionally higher (~68% than its normal occurrence (~2% alone. We hypothesize that phosphorylation may be a requisite for O-GlcNAc modification and tyrosine phosphorylation plays a role in the interplay between O-GlcNAc modification and serine/threonine phosphorylation in proteins. In other words, the interplay between O-GlcNAc modification and phosphorylation is not limited to serine/threonine phosphorylation but also includes tyrosine phosphorylation. Our hypothesis provides an opportunity to understand the underlying mechanism involved in O-GlcNAc modification and its interplay with serine/threonine phosphorylation in proteins. Furthermore, implication of our hypothesis extends to tyrosine kinase signaling.

Nutrient-driven O-GlcNAc in proteostasis and neurodegeneration.

Science.gov (United States)

Akan, Ilhan; Olivier-Van Stichelen, Stephanie; Bond, Michelle R; Hanover, John A

2018-01-01

Proteostasis is essential in the mammalian brain where post-mitotic cells must function for decades to maintain synaptic contacts and memory. The brain is dependent on glucose and other metabolites for proper function and is spared from metabolic deficits even during starvation. In this review, we outline how the nutrient-sensitive nucleocytoplasmic post-translational modification O-linked N-acetylglucosamine (O-GlcNAc) regulates protein homeostasis. The O-GlcNAc modification is highly abundant in the mammalian brain and has been linked to proteopathies, including neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's. C. elegans, Drosophila, and mouse models harboring O-GlcNAc transferase- and O-GlcNAcase-knockout alleles have helped define the role O-GlcNAc plays in development as well as age-associated neurodegenerative disease. These enzymes add and remove the single monosaccharide from protein serine and threonine residues, respectively. Blocking O-GlcNAc cycling is detrimental to mammalian brain development and interferes with neurogenesis, neural migration, and proteostasis. Findings in C. elegans and Drosophila model systems indicate that the dynamic turnover of O-GlcNAc is critical for maintaining levels of key transcriptional regulators responsible for neurodevelopment cell fate decisions. In addition, pathways of autophagy and proteasomal degradation depend on a transcriptional network that is also reliant on O-GlcNAc cycling. Like the quality control system in the endoplasmic reticulum which uses a 'mannose timer' to monitor protein folding, we propose that cytoplasmic proteostasis relies on an 'O-GlcNAc timer' to help regulate the lifetime and fate of nuclear and cytoplasmic proteins. O-GlcNAc-dependent developmental alterations impact metabolism and growth of the developing mouse embryo and persist into adulthood. Brain-selective knockout mouse models will be an important tool for understanding the role of O-GlcNAc in the

A new tomato NAC (NAM/ATAF1/2/CUC2) transcription factor, SlNAC4, functions as a positive regulator of fruit ripening and carotenoid accumulation.

Science.gov (United States)

Zhu, Mingku; Chen, Guoping; Zhou, Shuang; Tu, Yun; Wang, Yi; Dong, Tingting; Hu, Zongli

2014-01-01

Fruit ripening in tomato (Solanum lycopersicum) is a complicated development process affected by both endogenous hormonal and genetic regulators and external signals. Although the role of NOR, a member of the NAC domain family, in mediating tomato fruit ripening has been established, its underlying molecular mechanisms remain unclear. To explore further the role of NAC transcription factors in fruit ripening, we characterized a new tomato NAC domain protein, named SlNAC4, which shows high accumulation in sepal and at the onset of fruit ripening. Various stress treatments including wounding, NaCl, dehydration and low temperature significantly increased the expression of SlNAC4. Reduced expression of SlNAC4 by RNA interference (RNAi) in tomato resulted in delayed fruit ripening, suppressed Chl breakdown and decreased ethylene synthesis mediated mainly through reduced expression of ethylene biosynthesis genes of system-2, and reduced carotenoids by alteration of the carotenoid pathway flux. Transgenic tomato fruits also displayed significant down-regulation of multiple ripening-associated genes, indicating that SlNAC4 functions as a positive regulator of fruit ripening by affecting ethylene synthesis and carotenoid accumulation. Moreover, we also noted that SlNAC4 could not be induced by ethylene and may function upstream of the ripening regulator RIN and positively regulate its expression. Yeast two-hybrid assay further revealed that SlNAC4 could interact with both RIN and NOR protein. These results suggested that ethylene-dependent and -independent processes are regulated by SlNAC4 in the fruit ripening regulatory network.

The Rose (Rosa hybrida) NAC Transcription Factor 3 Gene, RhNAC3, Involved in ABA Signaling Pathway Both in Rose and Arabidopsis

OpenAIRE

Jiang, Guimei; Jiang, Xinqiang; Lü, Peitao; Liu, Jitao; Gao, Junping; Zhang, Changqing

2014-01-01

Plant transcription factors involved in stress responses are generally classified by their involvement in either the abscisic acid (ABA)-dependent or the ABA-independent regulatory pathways. A stress-associated NAC gene from rose (Rosa hybrida), RhNAC3, was previously found to increase dehydration tolerance in both rose and Arabidopsis. However, the regulatory mechanism involved in RhNAC3 action is still not fully understood. In this study, we isolated and analyzed the upstream regulatory seq...

The Wheat NAC Transcription Factor TaNAC2L Is Regulated at the Transcriptional and Post-Translational Levels and Promotes Heat Stress Tolerance in Transgenic Arabidopsis.

Science.gov (United States)

Guo, Weiwei; Zhang, Jinxia; Zhang, Ning; Xin, Mingming; Peng, Huiru; Hu, Zhaorong; Ni, Zhongfu; Du, Jinkun

2015-01-01

Heat stress poses a serious threat to global crop production. In efforts that aim to mitigate the adverse effects of heat stress on crops, a variety of genetic tools are being used to develop plants with improved thermotolerance. The characterization of important regulators of heat stress tolerance provides essential information for this aim. In this study, we examine the wheat (Triticum aestivum) NAC transcription factor gene TaNAC2L. High temperature induced TaNAC2L expression in wheat and overexpression of TaNAC2L in Arabidopsis thaliana enhanced acquired heat tolerance without causing obvious alterations in phenotype compared with wild type under normal conditions. TaNAC2L overexpression also activated the expression of heat-related genes in the transgenic Arabidopsis plants, suggesting that TaNAC2L may improve heat tolerance by regulating the expression of stress-responsive genes. Notably, TaNAC2L is also regulated at the post-translational level and might be degraded via a proteasome-mediated pathway. Thus, this wheat transcription factor may have potential uses in enhancing thermotolerance in crops.

The Wheat NAC Transcription Factor TaNAC2L Is Regulated at the Transcriptional and Post-Translational Levels and Promotes Heat Stress Tolerance in Transgenic Arabidopsis.

Directory of Open Access Journals (Sweden)

Weiwei Guo

Full Text Available Heat stress poses a serious threat to global crop production. In efforts that aim to mitigate the adverse effects of heat stress on crops, a variety of genetic tools are being used to develop plants with improved thermotolerance. The characterization of important regulators of heat stress tolerance provides essential information for this aim. In this study, we examine the wheat (Triticum aestivum NAC transcription factor gene TaNAC2L. High temperature induced TaNAC2L expression in wheat and overexpression of TaNAC2L in Arabidopsis thaliana enhanced acquired heat tolerance without causing obvious alterations in phenotype compared with wild type under normal conditions. TaNAC2L overexpression also activated the expression of heat-related genes in the transgenic Arabidopsis plants, suggesting that TaNAC2L may improve heat tolerance by regulating the expression of stress-responsive genes. Notably, TaNAC2L is also regulated at the post-translational level and might be degraded via a proteasome-mediated pathway. Thus, this wheat transcription factor may have potential uses in enhancing thermotolerance in crops.

NAC Transcription Factors in Senescence: From Molecular Structure to Function in Crops

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Dagmara Podzimska-Sroka

2015-07-01

Full Text Available Within the last decade, NAC transcription factors have been shown to play essential roles in senescence, which is the focus of this review. Transcriptome analyses associate approximately one third of Arabidopsis NAC genes and many crop NAC genes with senescence, thereby implicating NAC genes as important regulators of the senescence process. The consensus DNA binding site of the NAC domain is used to predict NAC target genes, and protein interaction sites can be predicted for the intrinsically disordered transcription regulatory domains of NAC proteins. The molecular characteristics of these domains determine the interactions in gene regulatory networks. Emerging local NAC-centered gene regulatory networks reveal complex molecular mechanisms of stress- and hormone-regulated senescence and basic physiological steps of the senescence process. For example, through molecular interactions involving the hormone abscisic acid, Arabidopsis NAP promotes chlorophyll degradation, a hallmark of senescence. Furthermore, studies of the functional rice ortholog, OsNAP, suggest that NAC genes can be targeted to obtain specific changes in lifespan control and nutrient remobilization in crop plants. This is also exemplified by the wheat NAM1 genes which promote senescence and increase grain zinc, iron, and protein content. Thus, NAC genes are promising targets for fine-tuning senescence for increased yield and quality.

Performances and nitrification properties of biological aerated filters with zeolite, ceramic particle and carbonate media.

Science.gov (United States)

Qiu, Liping; Zhang, Shoubin; Wang, Guangwei; Du, Mao'an

2010-10-01

The performance and nitrification properties of three BAFs, with ceramic, zeolite and carbonate media, respectively, were investigated to evaluate the feasibility of employing these materials as biological aerated filter media. All three BAFs shown a promising COD and SS removal performance, while influent pH was 6.5-8.1, air-liquid ratio was 5:1 and HRT was 1.25-2.5 h, respectively. Ammonia removal in BAFs was inhibited when organic and ammonia nitrogen loading were increased, but promoted effectively with the increase pH value. Zeolite and carbonate were more suitable for nitrification than ceramic particle when influent pH below 6.5. It is feasible to employ these media in BAF and adequate bed volume has to be supplied to satisfy the requirement of removal COD, SS and ammonia nitrogen simultaneously in a biofilter. The carbonate with a strong buffer capacity is more suitable to treat the wastewater with variable or lower pH. Copyright 2010 Elsevier Ltd. All rights reserved.

Asymmetric Evolution and Expansion of the NAC Transcription Factor in Polyploidized Cotton

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Kai Fan

2018-01-01

Full Text Available Polyploidy in Gossypium hirsutum conferred different properties from its diploid ancestors under the regulation of transcription factors. The NAC transcription factor is a plant-specific family that can be related to plant growth and development. So far, little is known about the NAC family in cotton. This study identified 495 NAC genes in three cotton species and investigated the evolution and expansion of different genome-derived NAC genes in cotton. We revealed 15 distinct NAC subfamilies in cotton. Different subfamilies had different gene proportions, expansion rate, gene loss rate, and orthologous exchange rate. Paleohexaploidization (35% and cotton-specific decaploidy (32% might have primarily led to the expansion of the NAC family in cotton. Half of duplication events in G. hirsutum were inherited from its diploid ancestor, and others might have occurred after interspecific hybridization. In addition, NAC genes in the At and Dt subgenomes displayed asymmetric molecular evolution, as evidenced by their different gene loss rates, orthologous exchange, evolutionary rates, and expression levels. The dominant duplication event was different during the cotton evolutionary history. Different genome-derived NACs might have interacted with each other, which ultimately resulted in morphogenetic evolution. This study delineated the expansion and evolutionary history of the NAC family in cotton and illustrated the different fates of NAC genes during polyploidization.

DNA-binding specificity and molecular functions of NAC transcription factors

DEFF Research Database (Denmark)

Olsen, Addie Nina; Ernst, Heidi Asschenfeldt; Lo Leggio, Leila

2005-01-01

The family of NAC (NAM/ATAF1,2/CUC2) transcription factors has been implicated in a wide range of plant processes, but knowledge on the DNA-binding properties of the family is limited. Using a reiterative selection procedure on random oligonucleotides, we have identified consensus binding sites....... Furthermore, NAC protein binding to the CaMV 35S promoter was shown to depend on sequences similar to the consensus of the selected oligonucleotides. Electrophoretic mobility shift assays demonstrated that NAC proteins bind DNA as homo- or heterodimers and that dimerization is necessary for stable DNA binding....... The ability of NAC proteins to dimerize and to bind DNAwas analysed by structure-based mutagenesis. This identified two salt bridge-forming residues essential for NAC protein dimerization. Alteration of basic residues in a loop region containing several highly conserved residues abolished DNA binding. Thus...

Overexpression of a Novel Apple NAC Transcription Factor Gene, MdNAC1, Confers the Dwarf Phenotype in Transgenic Apple (Malus domestica)

Science.gov (United States)

Jia, Dongfeng; Gong, Xiaoqing; Li, Mingjun; Li, Chao; Sun, Tingting

2018-01-01

Plant height is an important trait for fruit trees. The dwarf characteristic is commonly associated with highly efficient fruit production, a major objective when breeding for apple (Malus domestica). We studied the function of MdNAC1, a novel NAC transcription factor (TF) gene in apple related to plant dwarfing. Localized primarily to the nucleus, MdNAC1 has transcriptional activity in yeast cells. Overexpression of the gene results in a dwarf phenotype in transgenic apple plants. Their reduction in size is manifested by shorter, thinner stems and roots, and a smaller leaf area. The transgenics also have shorter internodes and fewer cells in the stems. Levels of endogenous abscisic acid (ABA) and brassinosteroid (BR) are lower in the transgenic plants, and expression is decreased for genes involved in the biosynthesis of those phytohormones. All of these findings demonstrate that MdNAC1 has a role in plants dwarfism, probably by regulating ABA and BR production. PMID:29702625

Genomewide identification, classification and analysis of NAC type ...

Indian Academy of Sciences (India)

NAC transcription factors comprise a large plant-specific gene family. Increasing evidence suggests that members of this family have diverse functions in plant growth and development. In this study, we performed a genomewide survey of NAC type genes in maize (Zea mays L.). A complete set of 148 nonredundant NAC ...

Genomewide identification, classification and analysis of NAC type ...

Indian Academy of Sciences (India)

Supplementary data: Genomewide identification, classification and analysis of NAC type gene family in maize. Xiaojian Peng, Yang Zhao, Xiaoming Li, Min Wu, Wenbo Chai, Lei Sheng, Yu Wang, Qing Dong,. Haiyang Jiang and Beijiu Cheng. J. Genet. 94, 377–390. Table 1. Detailed information of NAC proteins in maize.

Expression of polypeptide GalNAc-transferases in stratified epithelia and squamous cell carcinomas

DEFF Research Database (Denmark)

Mandel, U; Hassan, H; Therkildsen, M H

1999-01-01

GalNAc-T1, -T2, and -T3. Application of this panel of novel antibodies revealed that GalNAc- transferases are differentially expressed in different cell lines, in spermatozoa, and in oral mucosa and carcinomas. For example, GalNAc-T1 and -T2 but not -T3 were highly expressed in WI38 cells, and Gal......NAc-T3 but not GalNAc-T1 or -T2 was expressed in spermatozoa. The expression patterns in normal oral mucosa were found to vary with cell differentiation, and for GalNAc-T2 and -T3 this was reflected in oral squamous cell carcinomas. The expression pattern of GalNAc-T1 was on the other hand changed...

[A girl with self-harm treated with N-acetylcysteine (NAC)].

Science.gov (United States)

Rus, C P

Deliberate and recurrent self-harm could be regarded as addictive behaviour that can be treated with medication. In addiction, the dopaminergic mesolimbic reward system is activated. Pain caused by cutting stimulates the reward system through the opioid system. Glutamatergic neurotransmission follows the same pathway and plays a role in addiction as well. In this case-study a 17-year-old girl was successfully treated with N-acetylcysteine (nac) in order to reduce the frequency of self-cutting. In addition, in this case nac reduced the symptoms of attention deficit/hyperactivity disorder and depression. nac modulates the glutamatergic neurotransmission. This article provides possible explanations for the effect of nac in this case.

Process for producing ceramic nitrides anc carbonitrides and their precursors

Science.gov (United States)

Brown, G.M.; Maya, L.

1987-02-25

A process for preparing ceramic nitrides and carbon nitrides in the form of very pure, fine particulate powder. Appropriate precursors is prepared by reaching a transition metal alkylamide with ammonia to produce a mixture of metal amide and metal imide in the form of an easily pyrolyzable precipitate.

Structural basis of O-GlcNAc recognition by mammalian 14-3-3 proteins.

Science.gov (United States)

Toleman, Clifford A; Schumacher, Maria A; Yu, Seok-Ho; Zeng, Wenjie; Cox, Nathan J; Smith, Timothy J; Soderblom, Erik J; Wands, Amberlyn M; Kohler, Jennifer J; Boyce, Michael

2018-05-21

O-GlcNAc is an intracellular posttranslational modification that governs myriad cell biological processes and is dysregulated in human diseases. Despite this broad pathophysiological significance, the biochemical effects of most O-GlcNAcylation events remain uncharacterized. One prevalent hypothesis is that O-GlcNAc moieties may be recognized by "reader" proteins to effect downstream signaling. However, no general O-GlcNAc readers have been identified, leaving a considerable gap in the field. To elucidate O-GlcNAc signaling mechanisms, we devised a biochemical screen for candidate O-GlcNAc reader proteins. We identified several human proteins, including 14-3-3 isoforms, that bind O-GlcNAc directly and selectively. We demonstrate that 14-3-3 proteins bind O-GlcNAc moieties in human cells, and we present the structures of 14-3-3β/α and γ bound to glycopeptides, providing biophysical insights into O-GlcNAc-mediated protein-protein interactions. Because 14-3-3 proteins also bind to phospho-serine and phospho-threonine, they may integrate information from O-GlcNAc and O-phosphate signaling pathways to regulate numerous physiological functions.

Expression of LacdiNAc Groups on N-Glycans among Human Tumors Is Complex

Directory of Open Access Journals (Sweden)

Kiyoko Hirano

2014-01-01

Full Text Available Aberrant glycosylation of proteins and lipids is one of the characteristic features of malignantly transformed cells. The GalNAcβ1 → 4GlcNAc (LacdiNAc or LDN group at the nonreducing termini of both N- and O-glycans is not generally found in mammalian cells. We previously showed that the expression level of the LacdiNAc group in N-glycans decreases dramatically during the progression of human breast cancer. In contrast, the enhanced expression of the LacdiNAc group has been shown to be associated with the progression of human prostate, ovarian, and pancreatic cancers. Therefore, the expression of the disaccharide group appears to be dependent on types of tumors. The mechanism of formation of the LacdiNAc group in human tumors and cancer cells has been studied, and two β4-N-acetylgalacto-saminyltransferases (β4GalNAcTs, β4GalNAcT3 and β4GalNAcT4, have been shown to be involved in the biosynthesis of this disaccharide group in a tissue-dependent manner. Transfection of the β4GalNAcT3 gene brought about significant changes in the malignant phenotypes of human neuroblastoma, indicating that this disaccharide group is important for suppressing the tumor growth.

NACS Store Planning Manual.

Science.gov (United States)

College Store Journal, 1979

1979-01-01

Topics discussed by the NACS Store Planning/Renovation Committees in this updated version of the college store renovation manual include: short- and long-range planning, financial considerations, professional planning assistance, the store's image and business character, location considerations, building requirements, space requirements, fixtures,…

Functional O-GlcNAc modifications: Implications in molecular regulation and pathophysiology

Science.gov (United States)

Wells, Lance

2016-01-01

O-linked β-N-acetylglucosamine (O-GlcNAc) is a regulatory post-translational modification of intracellular proteins. The dynamic and inducible cycling of the modification is governed by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) in response to UDP-GlcNAc levels in the hexosamine biosynthetic pathway (HBP). Due to its reliance on glucose flux and substrate availability, a major focus in the field has been on how O-GlcNAc contributes to metabolic disease. For years this post-translational modification has been known to modify thousands of proteins implicated in various disorders, but direct functional connections have until recently remained elusive. New research is beginning to reveal the specific mechanisms through which O-GlcNAc influences cell dynamics and disease pathology including clear examples of O-GlcNAc modification at a specific site on a given protein altering its biological functions. The following review intends to focus primarily on studies in the last half decade linking O-GlcNAc modification of proteins with chromatin-directed gene regulation, developmental processes, and several metabolically related disorders including Alzheimer’s, heart disease and cancer. These studies illustrate the emerging importance of this post-translational modification in biological processes and multiple pathophysiologies. PMID:24524620

O-GlcNAc regulates NEDD4-1 stability via caspase-mediated pathway

International Nuclear Information System (INIS)

Jiang, Kuan; Bai, Bingyang; Ta, Yajie; Zhang, Tingling; Xiao, Zikang; Wang, Peng George; Zhang, Lianwen

2016-01-01

O-GlcNAc modification of cytosolic and nuclear proteins regulates essential cellular processes such as stress responses, transcription, translation, and protein degradation. Emerging evidence indicates O-GlcNAcylation has a dynamic interplay with ubiquitination in cellular regulation. Here, we report that O-GlcNAc indirectly targets a vital E3 ubiquitin ligase enzyme of NEDD4-1. The protein level of NEDD4-1 is accordingly decreased following an increase of overall O-GlcNAc level upon PUGNAc or glucosamine stimulation. O-GlcNAc transferase (OGT) knockdown, overexpression and mutation results confirm that the stability of NEDD4-1 is negatively regulated by cellular O-GlcNAc. Moreover, the NEDD4-1 degradation induced by PUGNAc or GlcN is significantly inhibited by the caspase inhibitor. Our study reveals a regulation mechanism of NEDD4-1 stability by O-GlcNAcylation. - Highlights: • Reduced NEDD4-1 correlates with increased overall O-GlcNAc level. • OGT negatively regulates NEDD4-1 stability. • O-GlcNAc regulates NEDD4-1 through caspase-mediated pathway.

Location, location, location: new insights into O-GalNAc protein glycosylation

DEFF Research Database (Denmark)

Gill, David J; Clausen, Henrik; Bard, Frederic

2011-01-01

O-GalNAc glycosylation of proteins confers essential structural, protective and signaling roles in eumetazoans. Addition of O-glycans onto proteins is an extremely complex process that regulates both sites of attachment and the types of oligosaccharides added. Twenty distinct polypeptide GalNAc......-transferases (GalNAc-Ts) initiate O-glycosylation and fine-tuning their expression provides a mechanism for regulating this action. Recently, a new mode of regulation has emerged where activation of Src kinase selectively redistributes Golgi-localized GalNAc-Ts to the ER. This relocalization results in a strong...... increase in the density of O-glycan decoration. In this review, we discuss how different mechanisms can regulate the number and the types of O-glycans decorating proteins. In addition, we speculate how Src-dependent relocation of GalNAc-Ts could play an important role in cancerous cellular transformation....

Probing polypeptide GalNAc-transferase isoform substrate specificities by in vitro analysis

DEFF Research Database (Denmark)

Kong, Yun; Joshi, Hiren J; Schjoldager, Katrine Ter-Borch Gram

2015-01-01

N-acetylgalactosaminyltransferase (GalNAc)-type (mucin-type) O-glycosylation is an abundant and highly diverse modification of proteins. This type of O-glycosylation is initiated in the Golgi by a large family of up to 20 homologous polypeptide GalNAc-T isoenzymes that transfer GalNAc to Ser, Thr...... and possibly Tyr residues. These GalNAc residues are then further elongated by a large set of glycosyltransferases to build a variety of complex O-glycan structures. What determines O-glycan site occupancy is still poorly understood, although it is clear that the substrate specificities of individual...... isoenzymes and the repertoire of GalNAc-Ts in cells are key parameters. The GalNAc-T isoenzymes are differentially expressed in cells and tissues in principle allowing cells to produce unique O-glycoproteomes dependent on the specific subset of isoforms present. In vitro analysis of acceptor peptide...

Niobia and tantala codoped orthorhombic zirconia ceramics

International Nuclear Information System (INIS)

Hoeftberger, M.; Gritzner, G.

1995-01-01

During recent studies it was found that codoping of zirconia with niobia and tantala yielded very corrosion resistant, orthorhombic zirconia ceramics. The powders for those novel ceramics were made via the sol-gel technique by hydrolysis of the respective metal propoxides; a method which required dry-box techniques during the preparation of the alkoxides. In these studies the authors investigated the fabrication of precursor material from aqueous solutions. The preparation of aqueous solutions of salts of zirconium, niobium and tantalum is hampered by rapid hydrolysis. Premature hydrolysis of the chlorides and oxichlorides of niobium, tantalum and zirconium can be, however, prevented in aqueous solutions of oxalic acid. Thus the authors investigated the coprecipitation of hydroxides as precursors by reacting oxalic acid solutions of the respective cations with aqueous ammonia. In addition they studied the effects of calcination and of hydrothermal conversion of the hydroxides to oxides on the powder characteristics and on the mechanical properties of the niobia and tantala codoped zirconia ceramics

Lectin Domains of Polypeptide GalNAc Transferases Exhibit Glycopeptide Binding Specificity

DEFF Research Database (Denmark)

Pedersen, Johannes W; Bennett, Eric P; Schjoldager, Katrine T-B G

2011-01-01

UDP-GalNAc:polypeptide a-N-acetylgalactosaminyltransferases (GalNAc-Ts) constitute a family of up to 20 transferases that initiate mucin-type O-glycosylation. The transferases are structurally composed of catalytic and lectin domains. Two modes have been identified for the selection...... of glycosylation sites by GalNAc-Ts: confined sequence recognition by the catalytic domain alone, and concerted recognition of acceptor sites and adjacent GalNAc-glycosylated sites by the catalytic and lectin domains, respectively. Thus far, only the catalytic domain has been shown to have peptide sequence...... on sequences of mucins MUC1, MUC2, MUC4, MUC5AC, MUC6, and MUC7 as well as a random glycopeptide bead library, we examined the binding properties of four different lectin domains. The lectin domains of GalNAc-T1, -T2, -T3, and -T4 bound different subsets of small glycopeptides. These results indicate...

Synthesis of a Benzene-containing C1-Phosphonate Analogue of UDP-GlcNAc for the Inhibition of O-GlcNAc Transferase

Energy Technology Data Exchange (ETDEWEB)

Im, Jungkyun [Soonchunhyang Univ., Asan (Korea, Republic of)

2016-01-15

I report here the design, synthesis, and biological evaluation of a new C1-phosphonate analogue of UDP-GlcNAc as a potential inhibitor of OGT, an enzyme responsible for O-GlcNAc modification. The analogue was designed to mimic the transition state of the natural donor involved in the enzymatic reaction. However, the analogue showed somehow low activity as an inhibitor of OGT.

Bivalent Carbohydrate Binding Is Required for Biological Activity of Clitocybe nebularis Lectin (CNL), the N,N′-Diacetyllactosediamine (GalNAcβ1–4GlcNAc, LacdiNAc)-specific Lectin from Basidiomycete C. nebularis*

Science.gov (United States)

Pohleven, Jure; Renko, Miha; Magister, Špela; Smith, David F.; Künzler, Markus; Štrukelj, Borut; Turk, Dušan; Kos, Janko; Sabotič, Jerica

2012-01-01

Lectins are carbohydrate-binding proteins that exert their biological activity by binding to specific cell glycoreceptors. We have expressed CNL, a ricin B-like lectin from the basidiomycete Clitocybe nebularis in Escherichia coli. The recombinant lectin, rCNL, agglutinates human blood group A erythrocytes and is specific for the unique glycan N,N′-diacetyllactosediamine (GalNAcβ1–4GlcNAc, LacdiNAc) as demonstrated by glycan microarray analysis. We here describe the crystal structures of rCNL in complex with lactose and LacdiNAc, defining its interactions with the sugars. CNL is a homodimeric lectin, each of whose monomers consist of a single ricin B lectin domain with its β-trefoil fold and one carbohydrate-binding site. To study the mode of CNL action, a nonsugar-binding mutant and nondimerizing monovalent CNL mutants that retain carbohydrate-binding activity were prepared. rCNL and the mutants were examined for their biological activities against Jurkat human leukemic T cells and the hypersensitive nematode Caenorhabditis elegans mutant strain pmk-1. rCNL was toxic against both, although the mutants were inactive. Thus, the bivalent carbohydrate-binding property of homodimeric CNL is essential for its activity, providing one of the rare pieces of evidence that certain activities of lectins are associated with their multivalency. PMID:22298779

O-GlcNAcase Expression is Sensitive to Changes in O-GlcNAc Homeostasis.

Science.gov (United States)

Zhang, Zhen; Tan, Ee Phie; VandenHull, Nicole J; Peterson, Kenneth R; Slawson, Chad

2014-01-01

O-linked N-acetylglucosamine (O-GlcNAc) is a post-translational modification involving an attachment of a single β-N-acetylglucosamine moiety to serine or threonine residues in nuclear and cytoplasmic proteins. Cellular O-GlcNAc levels are regulated by two enzymes: O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), which add and remove the modification, respectively. The levels of O-GlcNAc can rapidly change in response to fluctuations in the extracellular environment; however, O-GlcNAcylation returns to a baseline level quickly after stimulus removal. This process termed O-GlcNAc homeostasis appears to be critical to the regulation of many cellular functions including cell cycle progress, stress response, and gene transcription. Disruptions in O-GlcNAc homeostasis are proposed to lead to the development of diseases, such as cancer, diabetes, and Alzheimer's disease. O-GlcNAc homeostasis is correlated with the expression of OGT and OGA. We reason that alterations in O-GlcNAc levels affect OGA and OGT transcription. We treated several human cell lines with Thiamet-G (TMG, an OGA inhibitor) to increase overall O-GlcNAc levels resulting in decreased OGT protein expression and increased OGA protein expression. OGT transcript levels slightly declined with TMG treatment, but OGA transcript levels were significantly increased. Pretreating cells with protein translation inhibitor cycloheximide did not stabilize OGT or OGA protein expression in the presence of TMG; nor did TMG stabilize OGT and OGA mRNA levels when cells were treated with RNA transcription inhibitor actinomycin D. Finally, we performed RNA Polymerase II chromatin immunoprecipitation at the OGA promoter and found that RNA Pol II occupancy at the transcription start site was lower after prolonged TMG treatment. Together, these data suggest that OGA transcription was sensitive to changes in O-GlcNAc homeostasis and was potentially regulated by O-GlcNAc.

O-GlcNAc inhibits interaction between Sp1 and Elf-1 transcription factors

International Nuclear Information System (INIS)

Lim, Kihong; Chang, Hyo-Ihl

2009-01-01

The novel protein modification, O-linked N-acetylglucosamine (O-GlcNAc), plays an important role in various aspects of cell regulation. Although most of nuclear transcription regulatory factors are modified by O-GlcNAc, O-GlcNAc effects on transcription remain largely undefined yet. In this study, we show that O-GlcNAc inhibits a physical interaction between Sp1 and Elf-1 transcription factors, and negatively regulates transcription of placenta and embryonic expression oncofetal protein gene (Pem). These findings suggest that O-GlcNAc inhibits Sp1-mediated gene transcription possibly by interrupting Sp1 interaction with its cooperative factor.

Genome-Wide Analysis of the NAC Gene Family in Physic Nut (Jatropha curcas L.).

Science.gov (United States)

Wu, Zhenying; Xu, Xueqin; Xiong, Wangdan; Wu, Pingzhi; Chen, Yaping; Li, Meiru; Wu, Guojiang; Jiang, Huawu

2015-01-01

The NAC proteins (NAM, ATAF1/2 and CUC2) are plant-specific transcriptional regulators that have a conserved NAM domain in the N-terminus. They are involved in various biological processes, including both biotic and abiotic stress responses. In the present study, a total of 100 NAC genes (JcNAC) were identified in physic nut (Jatropha curcas L.). Based on phylogenetic analysis and gene structures, 83 JcNAC genes were classified as members of, or proposed to be diverged from, 39 previously predicted orthologous groups (OGs) of NAC sequences. Physic nut has a single intron-containing NAC gene subfamily that has been lost in many plants. The JcNAC genes are non-randomly distributed across the 11 linkage groups of the physic nut genome, and appear to be preferentially retained duplicates that arose from both ancient and recent duplication events. Digital gene expression analysis indicates that some of the JcNAC genes have tissue-specific expression profiles (e.g. in leaves, roots, stem cortex or seeds), and 29 genes differentially respond to abiotic stresses (drought, salinity, phosphorus deficiency and nitrogen deficiency). Our results will be helpful for further functional analysis of the NAC genes in physic nut.

Molecular Evolution and Expansion Analysis of the NAC Transcription Factor in Zea mays

Science.gov (United States)

Fan, Kai; Wang, Ming; Miao, Ying; Ni, Mi; Bibi, Noreen; Yuan, Shuna; Li, Feng; Wang, Xuede

2014-01-01

NAC (NAM, ATAF1, 2 and CUC2) family is a plant-specific transcription factor and it controls various plant developmental processes. In the current study, 124 NAC members were identified in Zea mays and were phylogenetically clustered into 13 distinct subfamilies. The whole genome duplication (WGD), especially an additional WGD event, may lead to expanding ZmNAC members. Different subfamily has different expansion rate, and NAC subfamily preference was found during the expansion in maize. Moreover, the duplication events might occur after the divergence of the lineages of Z. mays and S. italica, and segmental duplication seemed to be the dominant pattern for the gene duplication in maize. Furthermore, the expansion of ZmNAC members may be also related to gain and loss of introns. Besides, the restriction of functional divergence was discovered after most of the gene duplication events. These results could provide novel insights into molecular evolution and expansion analysis of NAC family in maize, and advance the NAC researches in other plants, especially polyploid plants. PMID:25369196

Efficient 1H-NMR Quantitation and Investigation of N-Acetyl-D-glucosamine (GlcNAc and N,N'-Diacetylchitobiose (GlcNAc2 from Chitin

Directory of Open Access Journals (Sweden)

Huey-Lang Yang

2011-09-01

Full Text Available A quantitative determination method of N-acetyl-D-glucosamine (GlcNAc and N,N'-diacetylchitobiose (GlcNAc2 is proposed using a proton nuclear magnetic resonance experiment. N-acetyl groups of GlcNAc and (GlcNAc2 are chosen as target signals, and the deconvolution technique is used to determine the concentration of the corresponding compound. Compared to the HPLC method, 1H-NMR spectroscopy is simple and fast. The method can be used for the analysis of chitin hydrolyzed products with real-time analysis, and for quantifying the content of products using internal standards without calibration curves. This method can be used to quickly evaluate chitinase activity. The temperature dependence of 1H-NMR spectra (VT-NMR is studied to monitor the chemical shift variation of acetyl peak. The acetyl groups of products are involved in intramolecular H-bonding with the OH group on anomeric sites. The rotation of the acetyl group is closely related to the intramolecular hydrogen bonding pattern, as suggested by the theoretical data (molecular modeling.

NAC transcription factors in senescence

DEFF Research Database (Denmark)

Podzimska-Sroka, Dagmara; O'Shea, Charlotte; Gregersen, Per L.

2015-01-01

involving the hormone abscisic acid, Arabidopsis NAP promotes chlorophyll degradation, a hallmark of senescence. Furthermore, studies of the functional rice ortholog, OsNAP, suggest that NAC genes can be targeted to obtain specific changes in lifespan control and nutrient remobilization in crop plants...

An acetylation site in lectin domain modulates the biological activity of polypeptide GalNAc-transferase-2

DEFF Research Database (Denmark)

Zlocowski, Natacha; Lorenz, Virginia; Bennett, Eric Paul

2013-01-01

Abstract Polypeptide GalNAc-transferases (ppGalNAc-Ts) are a family of enzymes that catalyze the initiation of mucin-type O-glycosylation. All ppGalNAc-T family members contain a common (QXW)3 motif which is present in R-type lectin group. Acetylation site K521 is part of the QKW motif of ß......-trefoil in the lectin domain of ppGalNAc-T2. We used a combination of acetylation and site-directed mutagenesis approaches to examine the functional role of K521 in ppGalNAc-T2. Binding assays of non-acetylated and acetylated forms of the mutant ppGalNAc-T2K521Q to various naked and aGalNAc-glycosylated mucin peptides...... indicated that degree of interaction of lectin domain with aGalNAc depends on the peptide sequence of mucin. Studies of inhibitory effect of various carbohydrates on interactions of ppGalNAc-T2 with MUC1aGalNAc indicate that point K521Q mutation enhance the carbohydrate specificity of lectin domain for aGalNAc...

O-GlcNAcase expression is sensitive to changes in O-GlcNAc homeostasis

Directory of Open Access Journals (Sweden)

ZHEN eZHANG

2014-12-01

Full Text Available O-linked N-acetylglucosamine (O-GlcNAc is a post-translational modification involving an attachment of a single β-N-acetylglucosamine moiety to serine or threonine residues in nuclear and cytoplasmic proteins. Cellular O-GlcNAc levels are regulated by two enzymes: O-GlcNAc transferase (OGT and O-GlcNAcase (OGA, which add and remove the modification respectively. The levels of O-GlcNAc can rapidly change in response to fluctuations in the extracellular environment; however, O-GlcNAcylation returns to a baseline level quickly after stimulus removal. This process termed O-GlcNAc homeostasis appears to be critical to the regulation of many cellular functions including cell cycle progress, stress response, and gene transcription. Disruptions in O-GlcNAc homeostasis are proposed to lead to the development of diseases such as cancer, diabetes, and Alzheimer’s disease. O-GlcNAc homeostasis is correlated with the expression of OGT and OGA. We reason that alterations in O-GlcNAc levels affect OGA and OGT transcription. We treated several human cell lines with Thiamet-G (TMG, an OGA inhibitor to increase overall O-GlcNAc levels resulting in decreased OGT protein expression and increased OGA protein expression. OGT transcript levels slightly declined with TMG treatment, but OGA transcript levels were significantly increased. Pretreating cells with protein translation inhibitor cycloheximide (CHX did not stabilize OGT or OGA protein expression in the presence of TMG; nor did TMG stabilize OGT and OGA mRNA levels when cells were treated with RNA transcription inhibitor actinomycin D (AMD. Finally, we performed RNA Polymerase II chromatin immunoprecipitation (ChIP at the OGA promoter and found RNA Pol II occupancy at the transcription start site (TSS was lower after prolonged TMG treatment. Together, these data suggest that OGA transcription was sensitive to changes in O-GlcNAc homeostasis and was potentially regulated by O-GlcNAc.

Deconstruction of O-glycosylation-GalNAc-T isoforms direct distinct subsets of the O-glycoproteome

DEFF Research Database (Denmark)

Schjoldager, Katrine T; Joshi, Hiren J; Kong, Yun

2015-01-01

GalNAc-type O-glycosylation is found on most proteins trafficking through the secretory pathway in metazoan cells. The O-glycoproteome is regulated by up to 20 polypeptide GalNAc-Ts and the contributions and biological functions of individual GalNAc-Ts are poorly understood. Here, we used a zinc......-finger nuclease (ZFN)-directed knockout strategy to probe the contributions of the major GalNAc-Ts (GalNAc-T1 and GalNAc-T2) in liver cells and explore how the GalNAc-T repertoire quantitatively affects the O-glycoproteome. We demonstrate that the majority of the O-glycoproteome is covered by redundancy, whereas...... distinct subsets of substrates are modified by non-redundant functions of GalNAc-T1 and GalNAc-T2. The non-redundant O-glycoproteome subsets and specific transcriptional responses for each isoform are related to different cellular processes; for the GalNAc-T2 isoform, these support a role in lipid...

Hsp70-GlcNAc-binding activity is released by stress, proteasome inhibition, and protein misfolding

International Nuclear Information System (INIS)

Guinez, Celine; Mir, Anne-Marie; Leroy, Yves; Cacan, Rene; Michalski, Jean-Claude; Lefebvre, Tony

2007-01-01

Numerous recent works strengthen the idea that the nuclear and cytosolic-specific O-GlcNAc glycosylation protects cells against injuries. We have first investigated O-GlcNAc level and Hsp70-GlcNAc-binding activity (HGBA) behaviour after exposure of HeLa and HepG 2 cells to a wide variety of stresses. O-GlcNAc and HGBA responses were different according to the stress and according to the cell. HGBA was released for almost all stresses, while O-GlcNAc level was modified either upwards or downwards, depending to the stress. Against all expectations, we demonstrated that energy charge did not significantly vary with stress whereas UDP-GlcNAc pools were more dramatically affected even if differences in UDP-GlcNAc contents were not correlated with O-GlcNAc variations suggesting that O-GlcNAc transferase is itself finely regulated during cell injury. Finally, HGBA could be triggered by proteasome inhibition and by L-azetidine-2-carboxylic acid (a proline analogue) incorporation demonstrating that protein misfolding is one of the key-activator of this Hsp70 property

Dissolution of copper in chloride/ammonia mixtures and the implications for the stress corrosion cracking of copper containers

International Nuclear Information System (INIS)

King, F.; Greidanus, G.; Jobe, D.J.

1999-05-01

Stress-corrosion cracking is a possible failure mechanism for copper nuclear fuel waste disposal containers. One species known to cause the stress corrosion of copper alloys is ammonia. It is conceivable that ammonia could be produced in a disposal vault under certain, very specific conditions. There are a number of conditions, however, that mitigate against container failure by stress corrosion, one of which is the presence of chloride ions in deep Canadian Shield groundwaters. There are a number of reports in the literature that suggest that Cl - has an inhibitive effect on the stress corrosion of Cu alloys in ammonia solutions. The electrochemical behaviour of Cu in Cl - /ammonia solutions has been studied as a function of ammonia concentration, pH, the rate of mass transport and electrochemical potential. In particular, the effects of these parameters on the formation Of Cu 2 O films and the steady-state dissolution behaviour have been determined. All experiments were carried out in 0.1 mol·dm -3 NaC1 as a base solution. A series of aqueous speciation and equilibrium potential/pH diagrams are also presented for the quaternary system Cu-C1 - NH 3 /NH 4 + H 2 O. These diagrams are used to interpret the results of the electrochemical experiments reported here. In addition, it is demonstrated how these diagrams could be used to predict the time-dependence of the susceptibility to stress corrosion cracking of Cu containers in a disposal vault. (author)

Preliminary design report for the NAC combined transport cask

International Nuclear Information System (INIS)

1990-04-01

Nuclear Assurance Corporation (NAC) is under contract to the United States Department of Energy (DOE) to design, license, develop and test models, and fabricate a prototype cask transportation system for nuclear spent fuel. The design of this combined transport (rail/barge) transportation system has been divided into two phases, a preliminary design phase and a final design phase. This Preliminary Design Package (PDP) describes the NAC Combined Transport Cask (NAC-CTC), the results of work completed during the preliminary design phase and identifies the additional detailed analyses, which will be performed during final design. Preliminary analytical results are presented in the appropriate sections and supplemented by summaries of procedures and assumptions for performing the additional detailed analyses of the final design. 60 refs., 1 fig., 2 tabs

Molecular characterization of banana NAC transcription factors and their interactions with ethylene signalling component EIL during fruit ripening.

Science.gov (United States)

Shan, Wei; Kuang, Jian-fei; Chen, Lei; Xie, Hui; Peng, Huan-huan; Xiao, Yun-yi; Li, Xue-ping; Chen, Wei-xin; He, Quan-guang; Chen, Jian-ye; Lu, Wang-jin

2012-09-01

The plant-specific NAC (NAM, ATAF1/2, and CUC2) transcription factors (TFs) play important roles in plant growth, development, and stress responses. However, the precise role of NAC TFs in relation to fruit ripening is poorly understood. In this study, six NAC genes, designated MaNAC1-MaNAC6, were isolated and characterized from banana fruit. Subcellular localization showed that MaNAC1-MaNAC5 proteins localized preferentially to the nucleus, while MaNAC6 was distributed throughout the entire cell. A transactivation assay in yeast demonstrated that MaNAC4 and MaNAC6, as well as their C-terminal regions, possessed trans-activation activity. Gene expression profiles in fruit with four different ripening characteristics, including natural, ethylene-induced, 1-methylcyclopropene (1-MCP)-delayed, and a combination of 1-MCP with ethylene treatment, revealed that the MaNAC genes were differentially expressed in peel and pulp during post-harvest ripening. MaNAC1 and MaNAC2 were apparently upregulated by ethylene in peel and pulp, consistent with the increase in ethylene production. In contrast, MaNAC3 in peel and pulp and MaNAC5 in peel were constitutively expressed, and transcripts of MaNAC4 in peel and pulp and MaNAC6 in peel decreased, while MaNAC5 or MaNAC6 in pulp increased slightly during fruit ripening. Furthermore, the MaNAC2 promoter was activated after ethylene application, further enhancing the involvement of MaNAC2 in fruit ripening. More importantly, yeast two-hybrid and bimolecular fluorescence complementation analyses confirmed that MaNAC1/2 physically interacted with a downstream component of ethylene signalling, ethylene insensitive 3 (EIN3)-like protein, termed MaEIL5, which was downregulated during ripening. Taken together, these results suggest that MaNACs such as MaNAC1/MaNAC2, may be involved in banana fruit ripening via interaction with ethylene signalling components.

Electrophoretic mobility shift assay reveals a novel recognition sequence for Setaria italica NAC protein.

Science.gov (United States)

Puranik, Swati; Kumar, Karunesh; Srivastava, Prem S; Prasad, Manoj

2011-10-01

The NAC (NAM/ATAF1,2/CUC2) proteins are among the largest family of plant transcription factors. Its members have been associated with diverse plant processes and intricately regulate the expression of several genes. Inspite of this immense progress, knowledge of their DNA-binding properties are still limited. In our recent publication,1 we reported isolation of a membrane-associated NAC domain protein from Setaria italica (SiNAC). Transactivation analysis revealed that it was a functionally active transcription factor as it could stimulate expression of reporter genes in vivo. Truncations of the transmembrane region of the protein lead to its nuclear localization. Here we describe expression and purification of SiNAC DNA-binding domain. We further report identification of a novel DNA-binding site, [C/G][A/T][T/A][G/C]TC[C/G][A/T][C/G][G/C] for SiNAC by electrophoretic mobility shift assay. The SiNAC-GST protein could bind to the NAC recognition sequence in vitro as well as to sequences where some bases had been reshuffled. The results presented here contribute to our understanding of the DNA-binding specificity of SiNAC protein.

[Cloning, subcellular localization, and heterologous expression of ApNAC1 gene from Andrographis paniculata].

Science.gov (United States)

Wang, Jian; Qi, Meng-Die; Guo, Juan; Shen, Ye; Lin, Hui-Xin; Huang, Lu-Qi

2017-03-01

Andrographis paniculata is widely used as medicinal herb in China for a long time and andrographolide is its main medicinal constituent. To investigate the underlying andrographolide biosynthesis mechanisms, RNA-seq for A. paniculata leaves with MeJA treatment was performed. In A. paniculata transcriptomic data, the expression pattern of one member of NAC transcription factor family (ApNAC1) matched with andrographolide accumulation. The coding sequence of ApNAC1 was cloned by RT-PCR, and GenBank accession number was KY196416. The analysis of bioinformatics showed that the gene encodes a peptide of 323 amino acids, with a predicted relative molecular weight of 35.9 kDa and isoelectric point of 6.14. To confirm the subcellular localization, ApNAC1-GFP was transiently expressed in A. paniculata protoplast. The results indicated that ApNAC1 is a nucleus-localized protein. The analysis of real-time quantitative PCR revealed that ApNAC1 gene predominantly expresses in leaves. Compared with control sample, its expression abundance sharply increased with methyl jasmonate treatment. Based on its expression pattern, ApNAC1 gene might involve in andrographolide biosynthesis. ApNAC1 was heterologously expressed in Escherichia coli and recombinant protein was purified by Ni-NTA agarose. Further study will help us to understand the function of ApNAC1 in andrographolide biosynthesis. Copyright© by the Chinese Pharmaceutical Association.

Interaction of hamster submaxillary sialyl-Tn and Tn glycoproteins with Gal, GalNAc and GlcNAc specific lectins.

Science.gov (United States)

Wu, A M; Shen, F; Herp, A; Wu, J H

1994-04-01

Hamster submaxillary glycoprotein (HSM), one of the simplest glycoproteins among mammalian salivary mucins, is composed of approximately equivalent amounts of protein, hexosamine and sialic acid. The Thr and Ser residues in the protein core account for more than half of all of the amino acid residues, while Lys, Glu, Pro and Ala are the major components of the remaining portion of amino acids. The carbohydrate side chains of this mucous glycoprotein have mainly the NeuAc-GalNAc-(sialyl-Tn) sequence (HSM), and those of the desialylated product (HSM-Tn) are almost exclusively unsubstituted GalNAc residues (Tn determinants). The binding properties of sialyl-Tn (HSM) and asialo-HSM (HSM-Tn) glycoproteins were tested by precipitin assay with Gal, GalNAc and GlcNAc specific lectins. The HSM-Tn completely precipitated Vicia villosa (VVL both B4 and mixture of A and B), Maclura pomifera (MPL), and Artocarpus integrifolia (Jacalin) lectins; less than 2 micrograms of HSM-Tn were required for precipitating 50% of 5.0-6.3 micrograms lectin nitrogen added. HSM-Tn also reacted well with Helix pomatia lectin (HPL), Wistaria floribunda lectin (WFL) and Abrus precatorius agglutinin (APA) and precipitated in each case over 81% of the lectin nitrogen added. The reactivity of HSM-Tn with other lectins (Ricinus communis, RCA1; Dolichol biflorus, DBL; Viscum album, ML-I; Arachis hypogaea, PNA, and Triticum vulgaris, WGA) was weak or negligible. The activity of sialyl-Tn (HSM) was more restricted; HSM reacted well with Jacalin, moderately with MPL and VVL-B4, but was inactive or only weakly with the other lectins used. These findings indicate that HSM and its desialylated product (HSM-Tn) are highly useful reagents for the differentiation of Tn and T/Gal specific lectins and for anti-T, Tn and Af monoclonal antibodies.

NAC, Neutron Activation Analysis and Isotope Inventory

International Nuclear Information System (INIS)

1995-01-01

1 - Description of program or function: NAC was designed to predict the neutron-induced gamma-ray radioactivity for a wide variety of composite materials. The NAC output includes the input data, a list of all reactions for each constituent element, and the end-of-irradiation disintegration rates for each reaction. NAC also compiles a product isotope inventory containing the isotope name, the disintegration rate, the gamma-ray source strength and the absorbed dose rate at 1 meter from an unshielded point source. The induced activity is calculated as a function of irradiation and decay times; the effect of cyclic irradiation can also be calculated. 2 - Method of solution: The standard neutron activation and decay equations are programmed. A data library is supplied which contains target element names, atomic densities, reaction indices, individual reactions and reaction parameters, and product isotopes and gamma energy yields. 3 - Restrictions on the complexity of the problem: Each composite material may consist of up to 20 different elements and up to 20 different decay times may be included. Both limits may be increased by the user by increasing the appropriate items in the dimension statement

O-GlcNAc transferase regulates transcriptional activity of human Oct4.

Science.gov (United States)

Constable, Sandii; Lim, Jae-Min; Vaidyanathan, Krithika; Wells, Lance

2017-10-01

O-linked β-N-acetylglucosamine (O-GlcNAc) is a single sugar modification found on many different classes of nuclear and cytoplasmic proteins. Addition of this modification, by the enzyme O-linked N-acetylglucosamine transferase (OGT), is dynamic and inducible. One major class of proteins modified by O-GlcNAc is transcription factors. O-GlcNAc regulates transcription factor properties through a variety of different mechanisms including localization, stability and transcriptional activation. Maintenance of embryonic stem (ES) cell pluripotency requires tight regulation of several key transcription factors, many of which are modified by O-GlcNAc. Octamer-binding protein 4 (Oct4) is one of the key transcription factors required for pluripotency of ES cells and more recently, the generation of induced pluripotent stem (iPS) cells. The action of Oct4 is modulated by the addition of several post-translational modifications, including O-GlcNAc. Previous studies in mice found a single site of O-GlcNAc addition responsible for transcriptional regulation. This study was designed to determine if this mechanism is conserved in humans. We mapped 10 novel sites of O-GlcNAc attachment on human Oct4, and confirmed a role for OGT in transcriptional activation of Oct4 at a site distinct from that found in mouse that allows distinction between different Oct4 target promoters. Additionally, we uncovered a potential new role for OGT that does not include its catalytic function. These results confirm that human Oct4 activity is being regulated by OGT by a mechanism that is distinct from mouse Oct4. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Peptide substrate-assisted study of O-GlcNAc transferase and O-GlcNAcylation

NARCIS (Netherlands)

Shi, Jie

2018-01-01

O-GlcNAcylation is a post translational modification (PTM) that corresponds to the addition of a single β-linked N-Acetyl-D-glucosamine (GlcNAc) sugar moiety onto the hydroxyl group of serine and threonine residues in numerous proteins. The addition of O-GlcNAc to proteins is catalyzed by O-GlcNAc

75 FR 42339 - List of Approved Spent Fuel Storage Casks: NAC-MPC System, Revision 6

Science.gov (United States)

2010-07-21

...-2010-0183] RIN 3150--AI88 List of Approved Spent Fuel Storage Casks: NAC-MPC System, Revision 6 AGENCY.... (NAC), NAC-MPC System listing within the ``List of Approved Spent Fuel Storage Casks'' to include... changes to the configuration of the NAC-MPC storage system as noted in Appendix B of the Technical...

The essence of NAC gene family to the cultivation of drought-resistant soybean (Glycine max L. Merr.) cultivars.

Science.gov (United States)

Hussain, Reem M; Ali, Mohammed; Feng, Xing; Li, Xia

2017-02-28

The NAC gene family is notable due to its large size, as well as its relevance in crop cultivation - particularly in terms of enhancing stress tolerance of plants. These plant-specific proteins contain NAC domain(s) that are named after Petunia NAM and Arabidopsis ATAF1/2 and CUC2 transcription factors based on the consensus sequence they have. Despite the knowledge available regarding NAC protein function, an extensive study on the possible use of GmNACs in developing soybean cultivars with superior drought tolerance is yet to be done. In response to this, our study was carried out, mainly through means of phylogenetic analysis (rice and Arabidopsis NAC genes served as seeding sequences). Through this, 139 GmNAC genes were identified and later grouped into 17 clusters. Furthermore, real-time quantitative PCR was carried out on drought-stressed and unstressed leaf tissues of both sensitive (B217 and H228) and tolerant (Jindou 74 and 78) cultivars. This was done to analyze the gene expression of 28 dehydration-responsive GmNAC genes. Upon completing the analysis, it was found that GmNAC gene expression is actually dependent on genotype. Eight of the 28 selected genes (GmNAC004, GmNAC021, GmNAC065, GmNAC066, GmNAC073, GmNAC082, GmNAC083 and GmNAC087) were discovered to have high expression levels in the drought-resistant soybean varieties tested. This holds true for both extreme and standard drought conditions. Alternatively, the drought-sensitive cultivars exhibited lower GmNAC expression levels in comparison to their tolerant counterparts. The study allowed for the identification of eight GmNAC genes that could be focused upon in future attempts to develop superior soybean varieties, particularly in terms of drought resistance. This study revealed that there were more dehydration-responsive GmNAC genes as (GmNAC004, GmNAC005, GmNAC020 and GmNAC021) in addition to what were reported in earlier inquiries. It is important to note though, that discovering such

Ammonia blood test

Science.gov (United States)

... page: //medlineplus.gov/ency/article/003506.htm Ammonia blood test To use the sharing features on this page, ... Encephalopathy - ammonia; Cirrhosis - ammonia; Liver failure - ammonia Images Blood test References Chernecky CC, Berger BJ. Ammonia (NH3) - blood ...

Dissolution of copper in chloride/ammonia mixtures and the implications for the stress corrosion cracking of copper containers

Energy Technology Data Exchange (ETDEWEB)

King, F.; Greidanus, G.; Jobe, D.J

1999-05-01

Stress-corrosion cracking is a possible failure mechanism for copper nuclear fuel waste disposal containers. One species known to cause the stress corrosion of copper alloys is ammonia. It is conceivable that ammonia could be produced in a disposal vault under certain, very specific conditions. There are a number of conditions, however, that mitigate against container failure by stress corrosion, one of which is the presence of chloride ions in deep Canadian Shield groundwaters. There are a number of reports in the literature that suggest that Cl{sup -} has an inhibitive effect on the stress corrosion of Cu alloys in ammonia solutions. The electrochemical behaviour of Cu in Cl{sup -}/ammonia solutions has been studied as a function of ammonia concentration, pH, the rate of mass transport and electrochemical potential. In particular, the effects of these parameters on the formation Of Cu{sub 2}O films and the steady-state dissolution behaviour have been determined. All experiments were carried out in 0.1 mol{center_dot}dm{sup -3} NaC1 as a base solution. A series of aqueous speciation and equilibrium potential/pH diagrams are also presented for the quaternary system Cu-C1{sup -}NH{sub 3}/NH{sub 4{sup +}}H{sub 2}O. These diagrams are used to interpret the results of the electrochemical experiments reported here. In addition, it is demonstrated how these diagrams could be used to predict the time-dependence of the susceptibility to stress corrosion cracking of Cu containers in a disposal vault. (author)

ST6GalNAc-I controls expression of sialyl-Tn antigen in gastrointestinal tissues

DEFF Research Database (Denmark)

Marcos, Nuno T; Bennett, Eric P; Gomes, Joana

2011-01-01

Sialyl-Tn is a simple mucin-type carbohydrate antigen aberrantly expressed in gastrointestinal adenocarcinomas and in the precursor lesion intestinal metaplasia. Sialyl-Tn tumour expression is an independent indicator of poor prognosis. We have previously shown in vitro that ST6GalNAc-I and ST6GalNAc......-II sialyltransferases can synthesize sialyl-Tn. The aim of the present study was to establish whether ST6GalNAc-I is the major enzyme responsible for the expression of sialyl-Tn. We used a model of CHO-ldlD cells producing only MUC1-Tn glycoform and showed that ST6GalNAc-I is the key-enzyme leading to sialyl......-Tn biosynthesis. We developed novel monoclonal antibodies specific for ST6GalNAc-I and evaluated its expression in gastrointestinal tissues. ST6GalNAc-I was detected in normal colon mucosa co-localized with O-acetylated sialyl-Tn. Expression was largely unaltered in colorectal adenocarcinomas. In contrast, we...

Method to remove ammonia using a proton-conducting ceramic membrane

Science.gov (United States)

Balachandran, Uthamalinga; Bose, Arun C

2003-10-07

An apparatus and method for decomposing NH.sub.3. A fluid containing NH.sub.3 is passed in contact with a tubular membrane that is a homogeneous mixture of a ceramic and a first metal, with the ceramic being selected from one or more of a cerate having the formula of M'Ce.sub.1-x M".sub.3-.delta., zirconates having the formula M'Zr.sub.1-x M"O.sub.3-.delta., stannates having the formula M'Sn.sub.1-x M'O.sub.3-.delta., where M' is a group IIA metal, M" is a dopant metal of one or more of Ca, Y, Yb, In, Nd, Gd or mixtures thereof and .delta. is a variable depending on the concentration of dopant and is in the range of from 0.001 to 0.5, the first metal is a group VIII or group IB element selected from the group consisting of Pt, Ag, Pd, Fe, Co, Cr, Mn, V, Ni, Au, Cu, Rh, Ru and mixtures thereof. The tubular membrane has a catalytic metal on the side thereof in contact with the fluid containing NH.sub.3 which is effective to cause NH.sub.3 to decompose to N.sub.2 and H.sub.2. When the H.sub.2 contacts the membrane H.sup.+ ions are formed which pass through the membrane driving the NH.sub.3 decomposition toward completion.

Functional significance of O-GlcNAc modification in regulating neuronal properties.

Science.gov (United States)

Hwang, Hongik; Rhim, Hyewhon

2018-03-01

Post-translational modifications (PTMs) covalently modify proteins and diversify protein functions. Along with protein phosphorylation, another common PTM is the addition of O-linked β-N-acetylglucosamine (O-GlcNAc) to serine and/or threonine residues. O-GlcNAc modification is similar to phosphorylation in that it occurs to serine and threonine residues and cycles on and off with a similar time scale. However, a striking difference is that the addition and removal of the O-GlcNAc moiety on all substrates are mediated by the two enzymes regardless of proteins, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), respectively. O-GlcNAcylation can interact or potentially compete with phosphorylation on serine and threonine residues, and thus serves as an important molecular mechanism to modulate protein functions and activation. However, it has been challenging to address the role of O-GlcNAc modification in regulating protein functions at the molecular level due to the lack of convenient tools to determine the sites and degrees of O-GlcNAcylation. Studies in this field have only begun to expand significantly thanks to the recent advances in detection and manipulation methods such as quantitative proteomics and highly selective small-molecule inhibitors for OGT and OGA. Interestingly, multiple brain regions, especially hippocampus, express high levels of both OGT and OGA, and a number of neuron-specific proteins have been reported to undergo O-GlcNAcylation. This review aims to discuss the recent updates concerning the impacts of O-GlcNAc modification on neuronal functions at multiple levels ranging from intrinsic neuronal properties to synaptic plasticity and animal behaviors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ammonia intoxication

International Nuclear Information System (INIS)

Bessman, S.P.; Pal, N.

1982-01-01

Data is presented which shows that there is a relation between ammonia concentration in the blood and state of consciousness. The concentrations of GTP and ATP also relate both to the ammonia concentration in blood and the state of consciousness. The rate of protein synthesis in the brain as measured by the percent of intracellular counts that are incorporated into protein is also related to ammonia concentration. These findings of energy depletion and depressed synthesis resulting from energy depletion suggest that the primary lesion in ammonia intoxication involves the Krebs cycle. The greater effect of ammonia on GTP than on ATP metabolism supports the view that the primary site of action of ammonia is at the glutamate dehydrogenase-ketoglutarate reduction step - and is consistent with previous work on this subject. (H.K.)

Protective Activity of N-acetyl-L-cysteine (NAC) against Cellular Oxidative Stress Induced by Radiation

Energy Technology Data Exchange (ETDEWEB)

Han, Min; Hyun, Kyung Man; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain); Aroutiounian, Rouben [Yerevan State University, Yerevan (Armenia)

2009-10-15

Oxidative stress occurs due to numerous factors such as irradiation, redox decomposition by ions of hydroperoxides or hydrogen peroxide, and thermal decomposition of free radical initiators including peroxides and hyponitrites. The antioxidant and free-radical scavenger N-acetyl- L-cysteine (NAC) is used extensively as a conditional nutrient. NAC acts as a cysteine donor and maintains or even increases the intracellular levels of glutathione (GSH), a tripeptide which protects cells from toxins such as free-radicals. With regard to the radioprotective effects of NAC, the majority of studies have been performed in vitro. NAC were used to protect the Chinese hamster ovary (CHO) cells from radiationinduced apoptosis by controlling the enzyme that triggers programmed cell death. Some studies have successfully demonstrated sporadic radioprotection following low-level chronic administration of NAC, though the mode and optimal dose of NAC are yet to be fully determined. This study was designed to evaluate the effects of NAC in different doses on the activity levels of GSH and the cell viability in the fish cell line against ionizing radiation.

Dynamic interplay between catalytic and lectin domains of GalNAc-transferases modulates protein O-glycosylation

DEFF Research Database (Denmark)

Lira-Navarrete, Erandi; de Las Rivas, Matilde; Compañón, Ismael

2015-01-01

the first crystal structures of complexes of GalNAc-T2 with glycopeptides that together with enhanced sampling molecular dynamics simulations demonstrate a cooperative mechanism by which the lectin domain enables free acceptor sites binding of glycopeptides into the catalytic domain. Atomic force microscopy......Protein O-glycosylation is controlled by polypeptide GalNAc-transferases (GalNAc-Ts) that uniquely feature both a catalytic and lectin domain. The underlying molecular basis of how the lectin domains of GalNAc-Ts contribute to glycopeptide specificity and catalysis remains unclear. Here we present...... and small-angle X-ray scattering experiments further reveal a dynamic conformational landscape of GalNAc-T2 and a prominent role of compact structures that are both required for efficient catalysis. Our model indicates that the activity profile of GalNAc-T2 is dictated by conformational heterogeneity...

The Novel Wheat Transcription Factor TaNAC47 Enhances Multiple Abiotic Stress Tolerances in Transgenic Plants.

Science.gov (United States)

Zhang, Lina; Zhang, Lichao; Xia, Chuan; Zhao, Guangyao; Jia, Jizeng; Kong, Xiuying

2015-01-01

NAC transcription factors play diverse roles in plant development and responses to abiotic stresses. However, the biological roles of NAC family members in wheat are not well understood. Here, we reported the isolation and functional characterization of a novel wheat TaNAC47 gene. TaNAC47 encoded protein, localizing in the nucleus, is able to bind to the ABRE cis-element and transactivate transcription in yeast, suggesting that it likely functions as a transcriptional activator. We also showed that TaNAC47 is differentially expressed in different tissues, and its expression was induced by the stress treatments of salt, cold, polyethylene glycol and exogenous abscisic acid. Furthermore, overexpression of TaNAC47 in Arabidopsis resulted in ABA hypersensitivity and enhancing tolerance of transgenic plants to drought, salt, and freezing stresses. Strikingly, overexpression of TaNAC47 was found to activate the expression of downstream genes and change several physiological indices that may enable transgenic plants to overcome unfavorable environments. Taken together, these results uncovered an important role of wheat TaNAC47 gene in response to ABA and abiotic stresses.

Operations experience with the NAC-1 legal weight truck cask

International Nuclear Information System (INIS)

Viebrock, J.M.; Hoffman, C.C.

1978-01-01

The first three years of operation of Nuclear Assurance Corporation's (NAC) four (4) NAC-1 Casks have demonstrated that shipments of spent fuel, fuel rods and other highly irradiated reactor components can be moved routinely by legal weight truck transport. Shipments of these materials have involved some 800,000 miles of highway travel and cask handling at some fifteen different nuclear facilities. This paper presents details on NAC's operations experience with these casks including cask description, cask handling (loading and unloading), pre-shipment testing, facility turnaround and transit times, operator exposure, transport vehicles and shipper/carrier/cask owner responsibilities, actual experience with regard to facility interfacing requirements and operational procedures. Cask and equipment utilization is discussed together with the methods used to control operation costs and to improve the economics of truck transport

Analysis of the stress-inducible transcription factor SsNAC23 in sugarcane plants

Directory of Open Access Journals (Sweden)

Renata Fava Ditt

2011-08-01

Full Text Available Stresses such as cold and drought can impair plant yield and induce a highly complex array of responses. Sugarcane (Saccharum spp. is cultivated in tropical and subtropical areas and is considered a cold-sensitive plant. We previously showed that cold stress induces the expression of several genes in in vitro sugarcane plantlets. Here we characterize one of those genes, SsNAC23, a member of the NAC family of plant-specific transcription factors, which are induced by low temperature and other stresses in several plant species. The expression of SsNAC23 was induced in sugarcane plants exposed to low temperatures (4ºC. With the aim of further understanding the regulatory network in response to stress, we used the yeast two-hybrid system to identify sugarcane proteins that interact with SsNAC23. Using SsNAC23 as bait, we screened a cDNA expression library of sugarcane plants submitted to 4ºC for 48 h. Several interacting partners were identified, including stress-related proteins, increasing our knowledge on how sugarcane plants respond to cold stress. One of these interacting partners, a thioredoxin h1, offers insights into the regulation of SsNAC23 activity.

Engineering the yeast Yarrowia lipolytica for the production of therapeutic proteins homogeneously glycosylated with Man8GlcNAc2 and Man5GlcNAc2

Directory of Open Access Journals (Sweden)

De Pourcq Karen

2012-05-01

Full Text Available Abstract Background Protein-based therapeutics represent the fastest growing class of compounds in the pharmaceutical industry. This has created an increasing demand for powerful expression systems. Yeast systems are widely used, convenient and cost-effective. Yarrowia lipolytica is a suitable host that is generally regarded as safe (GRAS. Yeasts, however, modify their glycoproteins with heterogeneous glycans containing mainly mannoses, which complicates downstream processing and often interferes with protein function in man. Our aim was to glyco-engineer Y. lipolytica to abolish the heterogeneous, yeast-specific glycosylation and to obtain homogeneous human high-mannose type glycosylation. Results We engineered Y. lipolytica to produce homogeneous human-type terminal-mannose glycosylated proteins, i.e. glycosylated with Man8GlcNAc2 or Man5GlcNAc2. First, we inactivated the yeast-specific Golgi α-1,6-mannosyltransferases YlOch1p and YlMnn9p; the former inactivation yielded a strain producing homogeneous Man8GlcNAc2 glycoproteins. We tested this strain by expressing glucocerebrosidase and found that the hypermannosylation-related heterogeneity was eliminated. Furthermore, detailed analysis of N-glycans showed that YlOch1p and YlMnn9p, despite some initial uncertainty about their function, are most likely the α-1,6-mannosyltransferases responsible for the addition of the first and second mannose residue, respectively, to the glycan backbone. Second, introduction of an ER-retained α-1,2-mannosidase yielded a strain producing proteins homogeneously glycosylated with Man5GlcNAc2. The use of the endogenous LIP2pre signal sequence and codon optimization greatly improved the efficiency of this enzyme. Conclusions We generated a Y. lipolytica expression platform for the production of heterologous glycoproteins that are homogenously glycosylated with either Man8GlcNAc2 or Man5GlcNAc2 N-glycans. This platform expands the utility of Y. lipolytica as a

O-GlcNAc profiling: from proteins to proteomes

Science.gov (United States)

2014-01-01

O-linked β-D-N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation) onto serine and threonine residues of proteins is an important post-translational modification (PTM), which is involved in many crucial biological processes including transcription, translation, proteasomal degradation, and signal transduction. Aberrant protein O-GlcNAcylation is directly linked to the pathological progression of chronic diseases including diabetes, cancer, and neurodegenerative disorders. Identification, site mapping, and quantification of O-GlcNAc proteins are a prerequisite to decipher their functions. In this review, we mainly focus on technological developments regarding O-GlcNAc protein profiling. Specifically, on one hand, we show how these techniques are being used for the comprehensive characterization of certain targeted proteins in which biologists are most interested. On the other hand, we present several newly developed approaches for O-GlcNAcomic profiling as well as how they provide us with a systems perspective to crosstalk amongst different PTMs and complicated biological events. Promising technical trends are also highlighted to evoke more efforts by diverse laboratories, which would further expand our understanding of the physiological and pathological roles of protein O-GlcNAcylation in chronic diseases. PMID:24593906

The novel wheat transcription factor TaNAC47 enhances multiple abiotic stress tolerances in transgenic plants

Directory of Open Access Journals (Sweden)

Li Na eZhang

2016-01-01

Full Text Available NAC transcription factors play diverse roles in plant development and responses to abiotic stresses. However, the biological roles of NAC family members in wheat are not well understood. Here, we reported the isolation and functional characterization of a novel wheat TaNAC47 gene. TaNAC47 encoded protein, localizing in the nucleus, is able to bind to the ABRE cis-element and transactivate transcription in yeast, suggesting that it likely functions as a transcriptional activator. We also showed that TaNAC47 is differentially expressed in different tissues, and its expression was induced by the stress treatments of salt, cold, polyethylene glycol (PEG and exogenous abscisic acid (ABA. Furthermore, overexpression of TaNAC47 in Arabidopsis resulted in ABA hypersensitivity and enhancing tolerance of transgenic plants to drought, salt and freezing stresses. Strikingly, overexpression of TaNAC47 was found to activate the expression of downstream genes and change several physiological indices that may enable transgenic plants to overcome unfavorable environments. Taken together, these results uncovered an important role of wheat TaNAC47 gene in response to ABA and abiotic stresses.

Enzymatic Synthesis of N-Acetyllactosamine (LacNAc Type 1 Oligomers and Characterization as Multivalent Galectin Ligands

Directory of Open Access Journals (Sweden)

Thomas Fischöder

2017-08-01

Full Text Available Repeats of the disaccharide unit N-acetyllactosamine (LacNAc occur as type 1 (Galβ1, 3GlcNAc and type 2 (Galβ1, 4GlcNAc glycosylation motifs on glycoproteins and glycolipids. The LacNAc motif acts as binding ligand for lectins and is involved in many biological recognition events. To the best of our knowledge, we present, for the first time, the synthesis of LacNAc type 1 oligomers using recombinant β1,3-galactosyltransferase from Escherichia coli and β1,3-N-acetylglucosaminyltranferase from Helicobacter pylori. Tetrasaccharide glycans presenting LacNAc type 1 repeats or LacNAc type 1 at the reducing or non-reducing end, respectively, were conjugated to bovine serum albumin as a protein scaffold by squarate linker chemistry. The resulting multivalent LacNAc type 1 presenting neo-glycoproteins were further studied for specific binding of the tumor-associated human galectin 3 (Gal-3 and its truncated counterpart Gal-3∆ in an enzyme-linked lectin assay (ELLA. We observed a significantly increased affinity of Gal-3∆ towards the multivalent neo-glycoprotein presenting LacNAc type 1 repeating units. This is the first evidence for differences in glycan selectivity of Gal-3∆ and Gal-3 and may be further utilized for tracing Gal-3∆ during tumor progression and therapy.

Catalytic and glycan-binding abilities of ppGalNAc-T2 are regulated by acetylation

DEFF Research Database (Denmark)

Zlocowski, Natacha; Sendra, Victor G; Lorenz, Virginia

2011-01-01

Post-translational acetylation is an important molecular regulatory mechanism affecting the biological activity of proteins. Polypeptide GalNAc transferases (ppGalNAc-Ts) are a family of enzymes that catalyze initiation of mucin-type O-glycosylation. All ppGalNAc-Ts in mammals are type II...

NAC international dry spent fuel transfer technology

International Nuclear Information System (INIS)

Shelton, Thomas A.; Malone, James P.; Patterson, John R.

1996-01-01

Full text: For more than ten years NAC International (NAC) has designed, fabricated, tested and operated a variety of Dry Transfer Systems (DTS's) to transfer spent nuclear fuel from facilities with limited crane capabilities, limited accesses or limiting features to IAEA and USNRC licensed spent fuel transport casks or vice-versa. These DTS's have been operated in diverse environments in the United States and throughout the world and have proven to be a significant enhancement in transferring fuel between spent fuel pools, dry storage and hot cell facilities and spent fuel transport casks. Over the years, NAC has successfully and safely transferred more than two thousand fuel assemblies in DTS's. Our latest generation DTS incorporates years of extensive design and operating experience. It consists of a transfer cask with integrated fuel canister grapple, fuel canisters, and facility and cask adapters as well as a complement of related tools and equipment. The transfer cask is used to move irradiated HEU and LEU MTR fuel onsite in those instances where direct loading or unloading of the shipping cask is not possible due to dimensional, weight or other restrictions. The transfer cask is used to move canisters of fuel from the fuel storage location to the shipping cask. Adapters are employed to ensure proper interfacing of the transfer cask with fuel storage locations and shipping casks (NAC-LWT and NLI-1/2). Our existing fuel storage location adapter is designed for use with a storage pool; however, site or equipment specific adapters can easily be developed to allow interfacing with virtually any storage facility. Prior to movement of the first fuel canister in the transfer cask, the shipping cask is prepared for loading by proper set up of the base plate, shipping cask and shipping cask adapter. The fuel canisters are loaded with fuel and then retracted into the transfer cask via the fuel storage location adapter. The transfer cask is then moved to the shipping

The early metazoan Trichoplax adhaerens possesses a functional O-GlcNAc system

NARCIS (Netherlands)

Selvan, Nithya; Mariappa, Daniel; Van Den Toorn, Henk W P; Heck, Albert J R; Ferenbach, Andrew T.; Van Aalten, Daan M F

2015-01-01

Protein O-GlcNAcylation is a reversible post-translational signaling modification of nucleocytoplasmic proteins that is essential for embryonic development in bilateria. In a search for a reductionist model to study O-GlcNAc signaling, we discovered the presence of functional O-GlcNAc transferase

Genome-wide organization and expression profiling of the NAC transcription factor family in potato (Solanum tuberosum L.).

Science.gov (United States)

Singh, Anil Kumar; Sharma, Vishal; Pal, Awadhesh Kumar; Acharya, Vishal; Ahuja, Paramvir Singh

2013-08-01

NAC [no apical meristem (NAM), Arabidopsis thaliana transcription activation factor [ATAF1/2] and cup-shaped cotyledon (CUC2)] proteins belong to one of the largest plant-specific transcription factor (TF) families and play important roles in plant development processes, response to biotic and abiotic cues and hormone signalling. Our genome-wide analysis identified 110 StNAC genes in potato encoding for 136 proteins, including 14 membrane-bound TFs. The physical map positions of StNAC genes on 12 potato chromosomes were non-random, and 40 genes were found to be distributed in 16 clusters. The StNAC proteins were phylogenetically clustered into 12 subgroups. Phylogenetic analysis of StNACs along with their Arabidopsis and rice counterparts divided these proteins into 18 subgroups. Our comparative analysis has also identified 36 putative TNAC proteins, which appear to be restricted to Solanaceae family. In silico expression analysis, using Illumina RNA-seq transcriptome data, revealed tissue-specific, biotic, abiotic stress and hormone-responsive expression profile of StNAC genes. Several StNAC genes, including StNAC072 and StNAC101that are orthologs of known stress-responsive Arabidopsis RESPONSIVE TO DEHYDRATION 26 (RD26) were identified as highly abiotic stress responsive. Quantitative real-time polymerase chain reaction analysis largely corroborated the expression profile of StNAC genes as revealed by the RNA-seq data. Taken together, this analysis indicates towards putative functions of several StNAC TFs, which will provide blue-print for their functional characterization and utilization in potato improvement.

ST6GalNAc-I controls expression of sialyl-Tn antigen in gastrointestinal tissues

DEFF Research Database (Denmark)

Marcos, Nuno T; Bennett, Eric Paul; Gomes, Joana

2011-01-01

-Tn biosynthesis. We developed novel monoclonal antibodies specific for ST6GalNAc-I and evaluated its expression in gastrointestinal tissues. ST6GalNAc-I was detected in normal colon mucosa co-localized with O-acetylated sialyl-Tn. Expression was largely unaltered in colorectal adenocarcinomas. In contrast, we......NAc-I as the major enzyme controlling the expression of cancer-associated sialyl-Tn antigen in gastrointestinal tissues....

Fabrication and testing of ceramic UO2 fuel - I-III. Part I

International Nuclear Information System (INIS)

Novakovic, M.

1961-12-01

The task described consists of the following: fabrication of UO 2 with different granulation from uranyl nitrate by ammonia diuranate; determination of size and shape distributions of metal and ceramic powders; fabrication of sintered pressed samples UO 2 ; investigating the properties of sintered uranium dioxide dependent on the fabrication process; producing a vibrator for compacting UO 2 powder. This volume includes reports on the first two tasks

Expression of a finger millet transcription factor, EcNAC1, in tobacco confers abiotic stress-tolerance.

Directory of Open Access Journals (Sweden)

Venkategowda Ramegowda

Full Text Available NAC (NAM, ATAF1-2, and CUC2 proteins constitute one of the largest families of plant-specific transcription factors and have been shown to be involved in diverse plant processes including plant growth, development, and stress-tolerance. In this study, a stress-responsive NAC gene, EcNAC1, was isolated from the subtracted stress cDNA library generated from a drought adapted crop, finger millet, and characterized for its role in stress-tolerance. The expression analysis showed that EcNAC1 was highly induced during water-deficit and salt stress. EcNAC1 shares high amino acid similarity with rice genes that have been phylogenetically classified into stress-related NAC genes. Our results demonstrated that tobacco transgenic plants expressing EcNAC1 exhibit tolerance to various abiotic stresses like simulated osmotic stress, by polyethylene glycol (PEG and mannitol, and salinity stress. The transgenic plants also showed enhanced tolerance to methyl-viologen (MV induced oxidative stress. Reduced levels of reactive oxygen species (ROS and ROS-induced damage were noticed in pot grown transgenic lines under water-deficit and natural high light conditions. Root growth under stress and recovery growth after stress alleviation was more in transgenic plants. Many stress-responsive genes were found to be up-regulated in transgenic lines expressing EcNAC1. Our results suggest that EcNAC1 overexpression confers tolerance against abiotic stress in susceptible species, tobacco.

Divergent Evolutionary Patterns of NAC Transcription Factors Are Associated with Diversification and Gene Duplications in Angiosperm

Directory of Open Access Journals (Sweden)

Xiaoli Jin

2017-06-01

Full Text Available NAC (NAM/ATAF/CUC proteins constitute one of the biggest plant-specific transcription factor (TF families and have crucial roles in diverse developmental programs during plant growth. Phylogenetic analyses have revealed both conserved and lineage-specific NAC subfamilies, among which various origins and distinct features were observed. It is reasonable to hypothesize that there should be divergent evolutionary patterns of NAC TFs both between dicots and monocots, and among NAC subfamilies. In this study, we compared the gene duplication and loss, evolutionary rate, and selective pattern among non-lineage specific NAC subfamilies, as well as those between dicots and monocots, through genome-wide analyses of sequence and functional data in six dicot and five grass lineages. The number of genes gained in the dicot lineages was much larger than that in the grass lineages, while fewer gene losses were observed in the grass than that in the dicots. We revealed (1 uneven constitution of Clusters of Orthologous Groups (COGs and contrasting birth/death rates among subfamilies, and (2 two distinct evolutionary scenarios of NAC TFs between dicots and grasses. Our results demonstrated that relaxed selection, resulting from concerted gene duplications, may have permitted substitutions responsible for functional divergence of NAC genes into new lineages. The underlying mechanism of distinct evolutionary fates of NAC TFs shed lights on how evolutionary divergence contributes to differences in establishing NAC gene subfamilies and thus impacts the distinct features between dicots and grasses.

Precision mapping of the human O-GalNAc glycoproteome through SimpleCell technology

DEFF Research Database (Denmark)

Steentoft, Catharina; Vakhrushev, Sergey; Joshi, Hiren Jitendra

2013-01-01

Glycosylation is the most abundant and diverse posttranslational modification of proteins. While several types of glycosylation can be predicted by the protein sequence context, and substantial knowledge of these glycoproteomes is available, our knowledge of the GalNAc-type O-glycosylation is hig......Glycosylation is the most abundant and diverse posttranslational modification of proteins. While several types of glycosylation can be predicted by the protein sequence context, and substantial knowledge of these glycoproteomes is available, our knowledge of the GalNAc-type O......-glycosylation is highly limited. This type of glycosylation is unique in being regulated by 20 polypeptide GalNAc-transferases attaching the initiating GalNAc monosaccharides to Ser and Thr (and likely some Tyr) residues. We have developed a genetic engineering approach using human cell lines to simplify O...

Probing isoform-specific functions of polypeptide GalNAc-transferases using zinc finger nuclease glycoengineered SimpleCells

DEFF Research Database (Denmark)

Schjoldager, Katrine Ter-Borch Gram; Vakhrushev, Sergey Y; Kong, Yun

2012-01-01

to include proteome-wide discovery of unique functions of individual GalNAc-Ts. We used the GalNAc-T2 isoform implicated in dyslipidemia and the human HepG2 liver cell line to demonstrate unique functions of this isoform. We confirm that GalNAc-T2-directed site-specific O-glycosylation inhibits proprotein...... activation of the lipase inhibitor ANGPTL3 in HepG2 cells and further identify eight O-glycoproteins exclusively glycosylated by T2 of which one, ApoC-III, is implicated in dyslipidemia. Our study supports an essential role for GalNAc-T2 in lipid metabolism, provides serum biomarkers for GalNAc-T2 enzyme...

Ammonia Monitor

Science.gov (United States)

Sauer, Richard L. (Inventor); Akse, James R. (Inventor); Thompson, John O. (Inventor); Atwater, James E. (Inventor)

1999-01-01

Ammonia monitor and method of use are disclosed. A continuous, real-time determination of the concentration of ammonia in an aqueous process stream is possible over a wide dynamic range of concentrations. No reagents are required because pH is controlled by an in-line solid-phase base. Ammonia is selectively transported across a membrane from the process stream to an analytical stream to an analytical stream under pH control. The specific electrical conductance of the analytical stream is measured and used to determine the concentration of ammonia.

Effect of ozone on the performance of a hybrid ceramic membrane-biological activated carbon process.

Science.gov (United States)

Guo, Jianning; Hu, Jiangyong; Tao, Yi; Zhu, Jia; Zhang, Xihui

2014-04-01

Two hybrid processes including ozonation-ceramic membrane-biological activated carbon (BAC) (Process A) and ceramic membrane-BAC (Process B) were compared to treat polluted raw water. The performance of hybrid processes was evaluated with the removal efficiencies of turbidity, ammonia and organic matter. The results indicated that more than 99% of particle count was removed by both hybrid processes and ozonation had no significant effect on its removal. BAC filtration greatly improved the removal of ammonia. Increasing the dissolved oxygen to 30.0 mg/L could lead to a removal of ammonia with concentrations as high as 7.80 mg/L and 8.69 mg/L for Processes A and B, respectively. The average removal efficiencies of total organic carbon and ultraviolet absorbance at 254 nm (UV254, a parameter indicating organic matter with aromatic structure) were 49% and 52% for Process A, 51% and 48% for Process B, respectively. Some organic matter was oxidized by ozone and this resulted in reduced membrane fouling and increased membrane flux by 25%-30%. However, pre-ozonation altered the components of the raw water and affected the microorganisms in the BAC, which may impact the removals of organic matter and nitrite negatively. Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

NAC gets OK for waste canister, looks for buyers

International Nuclear Information System (INIS)

Newman, P.

1994-01-01

The Nuclear Regulatory Commission has given design approval to the first dual-purpose waste cansiter suitable for storing and transporting irradiated nuclear fuel. The cask could be commercially available by January 1995. NRC issued a transportation certificate for the canister, which was developed by Atlanta-based NAC Services Inc., a subsidiary of NAC Holding Inc. That certificate, which says the cask is a suitable vessel for transporting radioactive wastes by rail and truck, is the first credential of a two-part licensing process the design must acquire. Testing of the cask has been extensive, including drop tests and pin-puncture tests. Roughly 19 feet long and eight feet in diameter, the cask is designed to hold 26 pressurized water reactor fuel assemblies. NAC officials say the cask design will soon be adapted to accomodate larger boiling water reactor fuel assemblies. Utilities will need some convincing that the dual-purpose $1.5 million cask is worth the money, particularly since companies currently have no use for the cask's transportation capabilities

Enhanced mass spectrometric mapping of the human GalNAc-type O-glycoproteome with SimpleCells

DEFF Research Database (Denmark)

Vakhrushev, Sergey Y; Steentoft, Catharina; Vester-Christensen, Malene B

2013-01-01

Characterizing protein GalNAc-type O-glycosylation has long been a major challenge, and as a result, our understanding of this glycoproteome is particularly poor. Recently, we presented a novel strategy for high throughput identification of O-GalNAc glycosites using zinc finger nuclease gene......-engineered "SimpleCell" lines producing homogeneous truncated O-glycosylation. Total lysates of cells were trypsinized and subjected to lectin affinity chromatography enrichment, followed by identification of GalNAc O-glycopeptides by nLC-MS/MS, with electron transfer dissociation employed to specify sites of O...... of O-GalNAc attached to tyrosine. Furthermore, we uncovered ≈ 220 O-glycosites wherein the peptides were clearly identified, but the glycosites could not be unambiguously assigned to specific positions. The improved strategy should greatly facilitate high throughput characterization of the human GalNAc...

The Lectin Domain of the Polypeptide GalNAc Transferase Family of Glycosyltransferases (ppGalNAc Ts) Acts as a Switch Directing Glycopeptide Substrate Glycosylation in an N- or C-terminal Direction, Further Controlling Mucin Type O-Glycosylation

DEFF Research Database (Denmark)

Gerken, Thomas A; Revoredo, Leslie; Thome, Joseph J C

2013-01-01

and specificity that differ between transferase isoforms. For example, ppGalNAc T1, T2, and T14 prefer C-terminally placed GalNAc-O-Thr, whereas ppGalNAc T3 and T6 prefer N-terminally placed GalNAc-O-Thr. Several transferase isoforms, ppGalNAc T5, T13, and T16, display equally enhanced N- or C-terminal activities...... relative to the nonglycosylated control peptides. This N- and/or C-terminal selectivity is presumably due to weak glycopeptide binding to the lectin domain, whose orientation relative to the catalytic domain is dynamic and isoform-dependent. Such N- or C-terminal glycopeptide selectivity provides...

O-GlcNAc and the Cardiovascular System

Science.gov (United States)

Dassanayaka, Sujith; Jones, Steven P.

2014-01-01

The cardiovascular system is capable of robust changes in response to physiologic and pathologic stimuli through intricate signaling mechanisms. The area of metabolism has witnessed a veritable renaissance in the cardiovascular system. In particular, the post-translational β-O-linkage of N-acetylglucosamine (O-GlcNAc) to cellular proteins represents one such signaling pathway that has been implicated in the pathophysiology of cardiovascular disease. This highly dynamic protein modification may induce functional changes in proteins and regulate key cellular processes including translation, transcription, and cell death. In addition, its potential interplay with phosphorylation provides an additional layer of complexity to post-translational regulation. The hexosamine biosynthetic pathway generally requires glucose to form the nucleotide sugar, UDP-GlcNAc. Accordingly, O-GlcNAcylation may be altered in response to nutrient availability and cellular stress. Recent literature supports O-GlcNAcylation as an autoprotective response in models of acute stress (hypoxia, ischemia, oxidative stress). Models of sustained stress, such as pressure overload hypertrophy, and infarct-induced heart failure, may also require protein O-GlcNAcylation as a partial compensatory mechanism. Yet, in models of Type II diabetes, O-GlcNAcylation has been implicated in the subsequent development of vascular, and even cardiac, dysfunction. This review will address this apparent paradox and discuss the potential mechanisms of O-GlcNAc-mediated cardioprotection and cardiovascular dysfunction. This discussion will also address potential targets for pharmacologic interventions and the unique considerations related to such targets. PMID:24287310

Dynamic O-GlcNAc cycling at promoters of Caenorhabditis elegans genes regulating longevity, stress, and immunity.

Science.gov (United States)

Love, Dona C; Ghosh, Salil; Mondoux, Michelle A; Fukushige, Tetsunari; Wang, Peng; Wilson, Mark A; Iser, Wendy B; Wolkow, Catherine A; Krause, Michael W; Hanover, John A

2010-04-20

Nutrient-driven O-GlcNAcylation of key components of the transcription machinery may epigenetically modulate gene expression in metazoans. The global effects of GlcNAcylation on transcription can be addressed directly in C. elegans because knockouts of the O-GlcNAc cycling enzymes are viable and fertile. Using anti-O-GlcNAc ChIP-on-chip whole-genome tiling arrays on wild-type and mutant strains, we detected over 800 promoters where O-GlcNAc cycling occurs, including microRNA loci and multigene operons. Intriguingly, O-GlcNAc-marked promoters are biased toward genes associated with PIP3 signaling, hexosamine biosynthesis, and lipid/carbohydrate metabolism. These marked genes are linked to insulin-like signaling, metabolism, aging, stress, and pathogen-response pathways in C. elegans. Whole-genome transcriptional profiling of the O-GlcNAc cycling mutants confirmed dramatic deregulation of genes in these key pathways. As predicted, the O-GlcNAc cycling mutants show altered lifespan and UV stress susceptibility phenotypes. We propose that O-GlcNAc cycling at promoters participates in a molecular program impacting nutrient-responsive pathways in C. elegans, including stress, pathogen response, and adult lifespan. The observed impact of O-GlcNAc cycling on both signaling and transcription in C. elegans has important implications for human diseases of aging, including diabetes and neurodegeneration.

Characterization of senscence-associated NAC transcription factors in Barley (Hordeum Vulgare L.)

DEFF Research Database (Denmark)

Podzimska, Dagmara Agata

, such as yield, biomass production and nutrient quality, and NAC (NAM, ATAF1/2 and CUC2) transcription factors are promising targets for the breeding. The aim of this thesis was thus to assess the role of NAC transcription factors in regulation of senescence in barley (Hordeum vulgare L.) and to contribute...

Respiratory ammonia output and blood ammonia concentration during incremental exercise

NARCIS (Netherlands)

Ament, W; Huizenga, [No Value; Kort, E; van der Mark, TW; Grevink, RG; Verkerke, GJ

The aim of this study was to investigate whether the increase of ammonia concentration and lactate concentration in blood was accompanied by an increased expiration of ammonia during graded exercise. Eleven healthy subjects performed an incremental cycle ergometer test. Blood ammonia, blood lactate

Le double destin des archives Jean Sénac

Directory of Open Access Journals (Sweden)

Hamid Nacer-Khodja

2014-04-01

Full Text Available Les archives Jean Sénac (1926‑1973 sont constituées de deux fonds : un fonds déposé à la bibliothèque municipale de Marseille et un autre à la Bibliothèque nationale d’Algérie. Le premier fonds regroupe essentiellement les manuscrits de la période de l’écrivain en France (1950‑1952 et 1954‑1962. Le fonds de la Bibliothèque nationale d’Algérie – le plus riche quantitativement – correspond à deux grandes périodes de la vie et de l’œuvre de Sénac en Algérie, soit de 1926 à 1950 et de 1962 à 1973.

File list: His.PSC.05.H2BS112GlcNAc.AllCell [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available His.PSC.05.H2BS112GlcNAc.AllCell hg19 Histone H2BS112GlcNAc Pluripotent stem cell h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.PSC.05.H2BS112GlcNAc.AllCell.bed ...

The interdomain flexible linker of the polypeptide GalNAc transferases dictates their long-range glycosylation preferences

DEFF Research Database (Denmark)

Rivas, Matilde De Las; Lira-Navarrete, Erandi; Daniel, Earnest James Paul

2017-01-01

The polypeptide GalNAc-transferases (GalNAc-Ts), that initiate mucin-type O-glycosylation, consist of a catalytic and a lectin domain connected by a flexible linker. In addition to recognizing polypeptide sequence, the GalNAc-Ts exhibit unique long-range N- A nd/or C-terminal prior glycosylation ...

An OGA-Resistant Probe Allows Specific Visualization and Accurate Identification of O-GlcNAc-Modified Proteins in Cells.

Science.gov (United States)

Li, Jing; Wang, Jiajia; Wen, Liuqing; Zhu, He; Li, Shanshan; Huang, Kenneth; Jiang, Kuan; Li, Xu; Ma, Cheng; Qu, Jingyao; Parameswaran, Aishwarya; Song, Jing; Zhao, Wei; Wang, Peng George

2016-11-18

O-linked β-N-acetyl-glucosamine (O-GlcNAc) is an essential and ubiquitous post-translational modification present in nucleic and cytoplasmic proteins of multicellular eukaryotes. The metabolic chemical probes such as GlcNAc or GalNAc analogues bearing ketone or azide handles, in conjunction with bioorthogonal reactions, provide a powerful approach for detecting and identifying this modification. However, these chemical probes either enter multiple glycosylation pathways or have low labeling efficiency. Therefore, selective and potent probes are needed to assess this modification. We report here the development of a novel probe, 1,3,6-tri-O-acetyl-2-azidoacetamido-2,4-dideoxy-d-glucopyranose (Ac 3 4dGlcNAz), that can be processed by the GalNAc salvage pathway and transferred by O-GlcNAc transferase (OGT) to O-GlcNAc proteins. Due to the absence of a hydroxyl group at C4, this probe is less incorporated into α/β 4-GlcNAc or GalNAc containing glycoconjugates. Furthermore, the O-4dGlcNAz modification was resistant to the hydrolysis of O-GlcNAcase (OGA), which greatly enhanced the efficiency of incorporation for O-GlcNAcylation. Combined with a click reaction, Ac 3 4dGlcNAz allowed the selective visualization of O-GlcNAc in cells and accurate identification of O-GlcNAc-modified proteins with LC-MS/MS. This probe represents a more potent and selective tool in tracking, capturing, and identifying O-GlcNAc-modified proteins in cells and cell lysates.

Temporal and Spatial Stability of Ammonia-Oxidizing Archaea and Bacteria in Aquarium Biofilters

KAUST Repository

Bagchi, Samik; Vlaeminck, Siegfried E.; Sauder, Laura A.; Mosquera, Mariela; Neufeld, Josh D.; Boon, Nico; Poulain, Alexandre

2014-01-01

Nitrifying biofilters are used in aquaria and aquaculture systems to prevent accumulation of ammonia by promoting rapid conversion to nitrate via nitrite. Ammonia-oxidizing archaea (AOA), as opposed to ammonia-oxidizing bacteria (AOB), were recently identified as the dominant ammonia oxidizers in most freshwater aquaria. This study investigated biofilms from fixed-bed aquarium biofilters to assess the temporal and spatial dynamics of AOA and AOB abundance and diversity. Over a period of four months, ammonia-oxidizing microorganisms from six freshwater and one marine aquarium were investigated at 4–5 time points. Nitrogen balances for three freshwater aquaria showed that active nitrification by aquarium biofilters accounted for ≥81–86% of total nitrogen conversion in the aquaria. Quantitative PCR (qPCR) for bacterial and thaumarchaeal ammonia monooxygenase (amoA) genes demonstrated that AOA were numerically dominant over AOB in all six freshwater aquaria tested, and contributed all detectable amoA genes in three aquarium biofilters. In the marine aquarium, however, AOB outnumbered AOA by three to five orders of magnitude based on amoA gene abundances. A comparison of AOA abundance in three carrier materials (fine sponge, rough sponge and sintered glass or ceramic rings) of two three-media freshwater biofilters revealed preferential growth of AOA on fine sponge. Denaturing gel gradient electrophoresis (DGGE) of thaumarchaeal 16S rRNA genes indicated that community composition within a given biofilter was stable across media types. In addition, DGGE of all aquarium biofilters revealed low AOA diversity, with few bands, which were stable over time. Nonmetric multidimensional scaling (NMDS) based on denaturing gradient gel electrophoresis (DGGE) fingerprints of thaumarchaeal 16S rRNA genes placed freshwater and marine aquaria communities in separate clusters. These results indicate that AOA are the dominant ammonia-oxidizing microorganisms in freshwater aquarium

Temporal and Spatial Stability of Ammonia-Oxidizing Archaea and Bacteria in Aquarium Biofilters

KAUST Repository

Bagchi, Samik

2014-12-05

Nitrifying biofilters are used in aquaria and aquaculture systems to prevent accumulation of ammonia by promoting rapid conversion to nitrate via nitrite. Ammonia-oxidizing archaea (AOA), as opposed to ammonia-oxidizing bacteria (AOB), were recently identified as the dominant ammonia oxidizers in most freshwater aquaria. This study investigated biofilms from fixed-bed aquarium biofilters to assess the temporal and spatial dynamics of AOA and AOB abundance and diversity. Over a period of four months, ammonia-oxidizing microorganisms from six freshwater and one marine aquarium were investigated at 4–5 time points. Nitrogen balances for three freshwater aquaria showed that active nitrification by aquarium biofilters accounted for ≥81–86% of total nitrogen conversion in the aquaria. Quantitative PCR (qPCR) for bacterial and thaumarchaeal ammonia monooxygenase (amoA) genes demonstrated that AOA were numerically dominant over AOB in all six freshwater aquaria tested, and contributed all detectable amoA genes in three aquarium biofilters. In the marine aquarium, however, AOB outnumbered AOA by three to five orders of magnitude based on amoA gene abundances. A comparison of AOA abundance in three carrier materials (fine sponge, rough sponge and sintered glass or ceramic rings) of two three-media freshwater biofilters revealed preferential growth of AOA on fine sponge. Denaturing gel gradient electrophoresis (DGGE) of thaumarchaeal 16S rRNA genes indicated that community composition within a given biofilter was stable across media types. In addition, DGGE of all aquarium biofilters revealed low AOA diversity, with few bands, which were stable over time. Nonmetric multidimensional scaling (NMDS) based on denaturing gradient gel electrophoresis (DGGE) fingerprints of thaumarchaeal 16S rRNA genes placed freshwater and marine aquaria communities in separate clusters. These results indicate that AOA are the dominant ammonia-oxidizing microorganisms in freshwater aquarium

The Arabidopsis thaliana NAC transcription factor family: structure-function relationships and determinants of ANAC019 stress signalling

DEFF Research Database (Denmark)

Jensen, Michael K; Kjaersgaard, Trine; Nielsen, Michael M.

2010-01-01

-termini. Nine of the ten NAC domains analysed bind a previously identified conserved DNA target sequence with a CGT[GA] core, although with different affinities. Likewise, all but one of the NAC proteins analysed is dependent on the C-terminal region for transactivational activity. In silico analyses show......TFs (transcription factors) are modular proteins minimally containing a DBD (DNA-binding domain) and a TRD (transcription regulatory domain). NAC [for NAM (no apical meristem), ATAF, CUC (cup-shaped cotyledon)] proteins comprise one of the largest plant TF families. They are key regulators...... of stress perception and developmental programmes, and most share an N-terminal NAC domain. On the basis of analyses of gene expression data and the phylogeny of Arabidopsis thaliana NAC TFs we systematically decipher structural and functional specificities of the conserved NAC domains and the divergent C...

The role of O-GlcNAc signaling in the pathogenesis of diabetic retinopathy.

Science.gov (United States)

Semba, Richard D; Huang, Hu; Lutty, Gerard A; Van Eyk, Jennifer E; Hart, Gerald W

2014-04-01

Diabetic retinopathy is a leading cause of blindness worldwide. Despite laser and surgical treatments, antiangiogenic and other therapies, and strict metabolic control, many patients progress to visual impairment and blindness. New insights are needed into the pathophysiology of diabetic retinopathy in order to develop new methods to improve the detection and treatment of disease and the prevention of blindness. Hyperglycemia and diabetes result in increased flux through the hexosamine biosynthetic pathway, which, in turn, results in increased PTM of Ser/Thr residues of proteins by O-linked β-N-acetylglucosamine (O-GlcNAc). O-GlcNAcylation is involved in regulation of many nuclear and cytoplasmic proteins in a manner similar to protein phosphorylation. Altered O-GlcNAc signaling has been implicated in the pathogenesis of diabetes and may play an important role in the pathogenesis of diabetic retinopathy. The goal of this review is to summarize the biology of the hexosamine biosynthesis pathway and O-GlcNAc signaling, to present the current evidence for the role of O-GlcNAc signaling in diabetes and diabetic retinopathy, and to discuss future directions for research on O-GlcNAc in the pathogenesis of diabetic retinopathy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Differential binding properties of Gal/GalNAc specific lectins available for characterization of glycoreceptors.

Science.gov (United States)

Wu, A M; Song, S C; Sugii, S; Herp, A

1997-01-01

Differentiating the binding properties of applied lectins should facilitate the selection of lectins for characterization of glycoreceptors on the cell surface. Based on the binding specificities studied by inhibition assays of lectin-glycan interactions, over twenty Gal and/or GalNAc specific lectins have been divided into eight groups according to their specificity for structural units (lectin determinants), which are the disaccharide as all or part of the determinants and of GalNAc alpha 1-->Ser (Thr) of the peptide chain. A scheme of codes for lectin determinants is illustrated as follows: (1) F (GalNAc alpha 1-->3GalNAc), Forssman specific disaccharide--Dolichos biflorus (DBL), Helix pomatia (HPL) and Wistaria floribunda (WFL) lectins. (2) A (GalNAc alpha 1-->3 Gal), blood group A specific disaccharide--Codium fragile subspecies tomentosoides (CFT), Soy bean (SBL), Vicia villosa-A4 (VVL-A4), and Wistaria floribunda (WFL) lectins. (3) Tn (GalNAc alpha 1-->Ser (Thr) of the protein core)--Vicia villosa B4 (VVL-B4), Salvia sclarea (SSL), Maclura pomifera (MPL), Bauhinia purpurea alba (BPL) and Artocarpus integrifolia (Jacalin, AIL). (4) T (Gal beta 1-->3GalNAc), the mucin type sugar sequences on the human erythrocyte membrane(T alpha), T antigen or the disaccharides at the terminal nonreducing end of gangliosides (T beta)--Peanut (PNA), Bauhinia purpurea alba (BPL), Maclura pomifera (MPL), Sophora japonica (SJL), Artocarpus lakoocha (Artocarpin) lectins and Abrus precatorius agglutinin (APA).(5) I and II (Gal beta 1-->3(4)GlcNAc)--the disaccharide residue at the nonreducing end of the carbohydrate chains derived from either N- or O-glycosidic linkage--Ricinus communis agglutinin (RCA1), Datura stramonium (TAL, Thorn apple), Erythrina cristagalli (ECL, Coral tree), and Geodia cydonium (GCL). (6) B (Gal alpha 1-->3Gal), human blood group B specific disaccharide--Griffonia(Banderiaea) simplicifolia B4 (GSI-B4). (7) E (Gal alpha 1-->4Gal), receptors for pathogenic E

Nac1 promotes self-renewal of embryonic stem cells through direct transcriptional regulation of c-Myc.

Science.gov (United States)

Ruan, Yan; He, Jianrong; Wu, Wei; He, Ping; Tian, Yanping; Xiao, Lan; Liu, Gaoke; Wang, Jiali; Cheng, Yuda; Zhang, Shuo; Yang, Yi; Xiong, Jiaxiang; Zhao, Ke; Wan, Ying; Huang, He; Zhang, Junlei; Jian, Rui

2017-07-18

The pluripotency transcriptional network in embryonic stem cells (ESCs) is composed of distinct functional units including the core and Myc units. It is hoped that dissection of the cellular functions and interconnections of network factors will aid our understanding of ESC and cancer biology. Proteomic and genomic approaches have identified Nac1 as a member of the core pluripotency network. However, previous studies have predominantly focused on the role of Nac1 in psychomotor stimulant response and cancer pathogenesis. In this study, we report that Nac1 is a self-renewal promoting factor, but is not required for maintaining pluripotency of ESCs. Loss of function of Nac1 in ESCs results in a reduced proliferation rate and an enhanced differentiation propensity. Nac1 overexpression promotes ESC proliferation and delays ESC differentiation in the absence of leukemia inhibitory factor (LIF). Furthermore, we demonstrated that Nac1 directly binds to the c-Myc promoter and regulates c-Myc transcription. The study also revealed that the function of Nac1 in promoting ESC self-renewal appears to be partially mediated by c-Myc. These findings establish a functional link between the core and c-Myc-centered networks and provide new insights into mechanisms of stemness regulation in ESCs and cancer.

Lateral Root Development in Potato Is Mediated by Stu-mi164 Regulation of NAC Transcription Factor

Directory of Open Access Journals (Sweden)

Li Zhang

2018-03-01

Full Text Available The NAC designation is derived from petunia (Petunia hybrida gene NO APICAL MERISTEM (NAM and Arabidopsis genes ATAF1/ATAF2 and CUP-SHAPED COTYLEDON2 (CUC2, which belongs to the family of plant-specific transcription factors (TFs, and plays important role in plant development processes, such as response to biotic and abiotic stress, and hormone signaling. MicroRNAs (miRNAs are a class of small, non-coding endogenous RNAs which play versatile and significant role in plant stress response and development via negatively affecting gene expression at a post-transcriptional level. Here, we showed that Stu-mi164 had a complementary sequence in the CDS sequence of potato NAC TFs, and that NAC expression exhibited significant differences under osmotic stress. We measured expression levels of the Stu-mi164 target gene StNAC262 between control and PEG-treated plants using real-time PCR, and the results demonstrated that they had inverse relationship. We suggested that Stu-miR164 might drive overexpression of NAC gene under osmotic stress in potato. To confirm the regulation of NAC TFs by Stu-mi164, we developed transgenic plants, using Agrobacterium tumefaciens–mediated transformation, of the potato cultivars “Gannongshu 2” and “Kexin 3” overexpressing the Stu-mi164 or the TF StNAC262. Real-time PCR analysis of transgenic potato plants under osmotic (PEG stress, showed that potato plants overexpressing Stu-mi164 had reduced expression of StNAC262 and their osmotic resistance decreased. Furthermore, these plants had low number of lateral roots although the same length as the control. Our findings support the regulatory role of Stu-miRNAs in controlling plant response to osmotic stress via StNAC262.

Ammonia complexes of metals in aqueous solutions with high concentrations of ammonia

International Nuclear Information System (INIS)

Padar, T.G.; Novikov, L.K.; Stupko, T.V.; Isaev, I.D.; Pashkov, G.L.; Mironov, V.E.

1991-01-01

Potentiometric method, glass electrodes and Bierrum function were used to study the formation of ammonia complexes of magnesium, calcium, cadmium, zinc, copper(2) and silver in 2.0 mol/dm 3 aqueous solutions of ammonia nitrate with 0-18 mol/dm 3 ammonia concentrations at 25.0 deg C. Step constants of stability of studied complexes were calculated and their compositions were determined with account of nonideal character of aqueous-salt solutions with ammonia concentrations above 1.0 mol/dm 3 . Values of correction effects on salting out ammonia action for Bierrum function in solutions with 1.0-18 mol/dm 3 ammonia concentrations were found

Protein O-GlcNAc Modification Increases in White Blood Cells After a Single Bout of Physical Exercise.

Science.gov (United States)

Nagy, Tamás; Kátai, Emese; Fisi, Viktória; Takács, Tamás Tibor; Stréda, Antal; Wittmann, István; Miseta, Attila

2018-01-01

Protein O-linked N -acetylglucosamine (O-GlcNAc) is a dynamic posttranslational modification influencing the function of many intracellular proteins. Recently it was revealed that O-GlcNAc regulation is modified under various stress states, including ischemia and oxidative stress. Aside from a few contradictory studies based on animal models, the effect of exercise on O-GlcNAc is unexplored. To evaluate O-GlcNAc levels in white blood cells (WBC) of human volunteers following physical exercise. Young (age 30 ± 5.2), healthy male volunteers ( n  = 6) were enlisted for the study. Blood parameters including metabolites, ions, "necro"-enzymes, and cell counts were measured before and after a single bout of exercise (2-mile run). From WBC samples, we performed western blots to detect O-GlcNAc modified proteins. The distribution of O-GlcNAc in WBC subpopulations was assessed by flow cytometry. Elevation of serum lactic acid (increased from 1.3 ± 0.4 to 6.9 ± 1.7 mM), creatinine (from 77.5 ± 6.3 U/L to 102.2 ± 7.0 μM), and lactate dehydrogenase (from 318.5 ± 26.2 to 380.5 ± 33.2 U/L) confirmed the effect of exercise. WBC count also significantly increased (from 6.6 ± 1.0 to 8.4 ± 1.4 G/L). The level of O-GlcNAc modified proteins in WBCs showed significant elevation after exercise (85 ± 51%, p  O-GlcNAc status of WBCs. O-GlcNAc modification could be a natural process by which physical activity modulates the immune system. Further research could elucidate the role of O-GlcNAc during exercise and validate O-GlcNAc as a biomarker for fitness assessment.

NAC Transcription Factors in Stress Responses and Senescence

DEFF Research Database (Denmark)

O'Shea, Charlotte

Plant-specific NAM/ATAF/CUC (NAC) transcription factors have recently received considerable attention due to their significant roles in plant development and stress signalling. This interest has resulted in a number of physiological, genetic and cell biological studies of their functions. Some...... of these studies have also revealed emerging gene regulatory networks and protein-protein interaction networks. However, structural studies relating structure to function are lagging behind. Structure-function analysis of the NAC transcription factors has therefore been the main focus of this PhD thesis...... not involve significant folding-upon-binding but fuzziness or an extended ANAC046 region. The ANAC046 regulatory domain functions as an entropic chain with a bait for interactions with for example RCD1. RCD1 interacts with transcription factors from several different families, and the large stress...

Disruption of O-GlcNAc cycling in C. elegans perturbs Nucleotide Sugar pools and Complex Glycans

Directory of Open Access Journals (Sweden)

Salil K Ghosh

2014-11-01

Full Text Available The carbohydrate modification of serine and threonine residues with O-linked beta-N-acetylglucosamine (O-GlcNAc is ubiquitous and governs cellular processes ranging from cell signaling to apoptosis. The O-GlcNAc modification along with other carbohydrate modifications, including N-linked and O-linked glycans, glycolipids, and sugar polymers, all require the use of the nucleotide sugar UDP-GlcNAc, the end product of the hexosamine biosynthetic pathway. In this paper, we describe the biochemical consequences resulting from perturbation of the O-GlcNAc pathway in C. elegans lacking O-GlcNAc transferase and O-GlcNAcase activities. In ogt-1 null animals, steady-state levels of UDP-GlcNAc/UDP-GalNAc and UDP-glucose were substantially elevated. Transcripts of genes encoding for key members in the Hexosamine Biosynthetic Pathway (gfat-2, gna-2, C36A4.4 and trehalose metabolism (tre-1, tre-2, and tps-2 were elevated in ogt-1 null animals. While there is no evidence to suggest changes in the profile of N-linked glycans in the ogt-1 and oga-1 mutants, glycans insensitive to PNGase digestion (including O-linked glycans, glycolipids, and glycopolymers were altered in these strains. Our data supports that changes in O-GlcNAcylation alters nucleotide sugar production, overall glycan composition, and transcription of genes encoding glycan processing enzymes. These data along with our previous findings that disruption in O-GlcNAc cycling alters macronutrient storage underscores the noteworthy influence this posttranslational modification plays in nutrient sensing.

PpNAC1, a main regulator of phenylalanine biosynthesis and utilization in maritime pine.

Science.gov (United States)

Pascual, María Belén; Llebrés, María-Teresa; Craven-Bartle, Blanca; Cañas, Rafael A; Cánovas, Francisco M; Ávila, Concepción

2018-05-01

The transcriptional regulation of phenylalanine metabolism is particularly important in conifers, long-lived species that use large amounts of carbon in wood. Here, we show that the Pinus pinaster transcription factor, PpNAC1, is a main regulator of phenylalanine biosynthesis and utilization. A phylogenetic analysis classified PpNAC1 in the NST proteins group and was selected for functional characterization. PpNAC1 is predominantly expressed in the secondary xylem and compression wood of adult trees. Silencing of PpNAC1 in P. pinaster results in the alteration of stem vascular radial patterning and the down-regulation of several genes associated with cell wall biogenesis and secondary metabolism. Furthermore, transactivation and EMSA analyses showed that PpNAC1 is able to activate its own expression and PpMyb4 promoter, while PpMyb4 is able to activate PpMyb8, a transcriptional regulator of phenylalanine and lignin biosynthesis in maritime pine. Together, these results suggest that PpNAC1 is a functional ortholog of the ArabidopsisSND1 and NST1 genes and support the idea that key regulators governing secondary cell wall formation could be conserved between gymnosperms and angiosperms. Understanding the molecular switches controlling wood formation is of paramount importance for fundamental tree biology and paves the way for applications in conifer biotechnology. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

The Hv NAC6 transcription factor: a positive regulator of penetration resistance in barley and Arabidopsis

DEFF Research Database (Denmark)

Jensen, Michael Krogh; Rung, Jesper Henrik; Gregersen, Per Langkjaer

2007-01-01

Pathogens induce the expression of many genes encoding plant transcription factors, though specific knowledge of the biological function of individual transcription factors remains scarce. NAC transcription factors are encoded in plants by a gene family with proposed functions in both abiotic...... and biotic stress adaptation, as well as in developmental processes. In this paper, we provide convincing evidence that a barley NAC transcription factor has a direct role in regulating basal defence. The gene transcript was isolated by differential display from barley leaves infected with the biotrophic...... powdery mildew fungus, Blumeria graminis f.sp. hordei (Bgh). The full-length cDNA clone was obtained using 5'-RACE and termed HvNAC6, due to its high similarity to the rice homologue, OsNAC6. Gene silencing of HvNAC6 during Bgh inoculation compromises penetration resistance in barley epidermal cells...

Performance and fouling characteristics of different pore-sized submerged ceramic membrane bioreactors (SCMBR).

Science.gov (United States)

Jin, Le; Ng, How Yong; Ong, Say Leong

2009-01-01

The membrane bioreactor (MBR), a combination of activated sludge process and the membrane separation system, has been widely used in wastewater treatment. However, 90% of MBR reported were employing polymeric membranes. The usage of ceramic membranes in MBR is quite rare. Four submerged ceramic membrane bioreactors (SCMBRs) with different membrane pore size were used in this study to treat sewage. The results showed that the desirable carbonaceous removal of 95% and ammonia nitrogen removal of 98% were obtained for all the SCMBRs. It was also showed that the ceramic membranes were able to reject some portions of the protein and carbohydrate, whereby the carbohydrate rejection rate was much higher than that of protein. Membrane pore size did not significantly affect the COD and TOC removal efficiencies, the composition of EPS and SMP or the membrane rejection rate, although slight differences were observed. The SCMBR with the biggest membrane pore size fouled fastest, and membrane pore size was a main contributor for the different fouling potential observed.

Loss of UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 3 and reduced O-glycosylation in colon carcinoma cells selected for hepatic metastasis

DEFF Research Database (Denmark)

Kato, Kentaro; Takeuchi, Hideyuki; Kanoh, Akira

2010-01-01

O-glycosylation of mucin is initiated by the attachment of N-acetyl-D-galactosamine (GalNAc) to serine or threonine residues in mucin core polypeptides by UDPGalNAc:polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-Ts). It is not well understood how GalNAc attachment is regulated by multiple...... ppGalNAc-Ts in each cell. In the present study, the expression levels of murine ppGalNAc-Ts (mGalNAc-Ts), T1, T2, T3, T4, T6, and T7 were compared between mouse colon carcinoma colon 38 cells and variant SL4 cells, selected for their metastatic potentials, by using the competitive RT-PCR method....... The expression levels of mGalNAc-T1, T2, and T7 were slightly higher in the SL4 cells than in the colon 38 cells, whereas the expression level of mGalNAc-T3 in the SL4 cells was 1.5% of that in the colon 38 cells. Products of enzymatic incorporations of GalNAc residues into FITCPTTTPITTTTK peptide by the use...

Overexpression of TaNAC2D displays opposite responses to abiotic stresses between seedling and mature stage of transgenic Arabidopsis

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Quanjun Huang

2016-11-01

Full Text Available Environmental stresses frequently affect plant growth and development, and many genes have been found to be induced by unfavorable environmental conditions. Here, we reported the biological functions of TaNAC2D, a stress-related NAC (NAM, ATAF, and CUC gene from wheat. TaNAC2D showed transcriptional activator activity in yeast. TaNAC2D-GFP fusion protein was localized in the nucleus of wheat mesophyll protoplasts. TaNAC2D transcript abundance was significantly induced by NaCl, PEG6000, and abscisic acid (ABA at seedling stage, and repressed by NaCl and PEG6000 at mature plant stage. When TaNAC2D was introduced into Arabidopsis, the 35-day-old soil-grown TaNAC2D-overexpression (TaNAC2D-OX plants displayed slower stomatal closure, higher water loss rate, and more sensitivity to salt and drought stresses compared with WT plants. In contrast, TaNAC2D-OX seedlings, grown on 1/2 MS medium supplemented with different concentrations of NaCl, Mannitol, and MV, had enhanced tolerances to salt, osmotic and oxidative stresses during seed germination and post-germination periods. The opposite stress-responsive phenotypes of transgenic Arabidopsis were consistent with the expression patterns of TaNAC2D in wheat. Moreover, under high salinity and dehydration conditions, three marker genes, including NCED3, RD29A, and RD29B, were down-regulated in 35-d-old TaNAC2D-OX plants grown in soil and up-regulated in 14-d-old TaNAC2D-OX seedlings grown on 1/2 MS medium. Our results suggest that the change in growth stages and environmental conditions may regulate TaNAC2D’s function.

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

Science.gov (United States)

Stahl, David A.

2013-01-01

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopumilus maritimus SCM1 growing at two ammonia concentrations, as measured by combined ammonia and ammonium, one well above the Km for ammonia oxidation (∼500 μM) and the other well below the Km (ammonia-replete to ammonia-limiting conditions. Transcript levels for ammonia oxidation, CO2 fixation, and one of the ammonia transport genes were approximately the same at high and low ammonia availability. Transcripts for all analyzed genes decreased with time in the complete absence of ammonia, but with various rates of decay. The new steady-state mRNA levels established are presumably more reflective of the natural physiological state of ammonia-oxidizing archaea and offer a reference for interpreting message abundance patterns in the natural environment. PMID:23995944

Interaction between O-GlcNAc modification and tyrosine phosphorylation of prohibitin: implication for a novel binary switch.

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Sudharsana R Ande

Full Text Available Prohibitin (PHB or PHB1 is an evolutionarily conserved, multifunctional protein which is present in various cellular compartments including the plasma membrane. However, mechanisms involved in various functions of PHB are not fully explored yet. Here we report for the first time that PHB interacts with O-linked beta-N-acetylglucosamine transferase (O-GlcNAc transferase, OGT and is O-GlcNAc modified; and also undergoes tyrosine phosphorylation in response to insulin. Tyrosine 114 (Tyr114 and tyrosine 259 (Tyr259 in PHB are in the close proximity of potential O-GlcNAc sites serine 121 (Ser121 and threonine 258 (Thr258 respectively. Substitution of Tyr114 and Tyr259 residues in PHB with phenylalanine by site-directed mutagenesis results in reduced tyrosine phosphorylation as well as reduced O-GlcNAc modification of PHB. Surprisingly, this also resulted in enhanced tyrosine phosphorylation and activity of OGT. This is attributed to the presence of similar tyrosine motifs in PHB and OGT. Substitution of Ser121 and Thr258 with alanine and isoleucine respectively resulted in attenuation of O-GlcNAc modification and increased tyrosine phosphorylation of PHB suggesting an association between these two dynamic modifications. Sequence analysis of O-GlcNAc modified proteins having known O-GlcNAc modification site(s or known tyrosine phosphorylation site(s revealed a strong potential association between these two posttranslational modifications in various proteins. We speculate that O-GlcNAc modification and tyrosine phosphorylation of PHB play an important role in tyrosine kinase signaling pathways including insulin, growth factors and immune receptors signaling. In addition, we propose that O-GlcNAc modification and tyrosine phosphorylation is a novel previously unidentified binary switch which may provide new mechanistic insights into cell signaling pathways and is open for direct experimental examination.

NAC Transcription Factors of Barley (Hordeum vulgare L.) and their Involvement in Leaf Senescence

DEFF Research Database (Denmark)

Wagner, Michael

parts of the senescence process. The specific aims of this study were therefore (1) to establish and characterise the NAC transcription factors of the model cereal crop barley (Hordeum vulgare L.) (2) to identify and study putative barley NAC transcription factors involved in the regulation of leaf...

Comparative Genomics of NAC Transcriptional Factors in Angiosperms: Implications for the Adaptation and Diversification of Flowering Plants

Science.gov (United States)

Pereira-Santana, Alejandro; Alcaraz, Luis David; Castaño, Enrique; Sanchez-Calderon, Lenin; Sanchez-Teyer, Felipe; Rodriguez-Zapata, Luis

2015-01-01

NAC proteins constitute one of the largest groups of plant-specific transcription factors and are known to play essential roles in various developmental processes. They are also important in plant responses to stresses such as drought, soil salinity, cold, and heat, which adversely affect growth. The current knowledge regarding the distribution of NAC proteins in plant lineages comes from relatively small samplings from the available data. In the present study, we broadened the number of plant species containing the NAC family origin and evolution to shed new light on the evolutionary history of this family in angiosperms. A comparative genome analysis was performed on 24 land plant species, and NAC ortholog groups were identified by means of bidirectional BLAST hits. Large NAC gene families are found in those species that have experienced more whole-genome duplication events, pointing to an expansion of the NAC family with divergent functions in flowering plants. A total of 3,187 NAC transcription factors that clustered into six major groups were used in the phylogenetic analysis. Many orthologous groups were found in the monocot and eudicot lineages, but only five orthologous groups were found between P. patens and each representative taxa of flowering plants. These groups were called basal orthologous groups and likely expanded into more recent taxa to cope with their environmental needs. This analysis on the angiosperm NAC family represents an effort to grasp the evolutionary and functional diversity within this gene family while providing a basis for further functional research on vascular plant gene families. PMID:26569117

Comparative Genomics of NAC Transcriptional Factors in Angiosperms: Implications for the Adaptation and Diversification of Flowering Plants.

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Alejandro Pereira-Santana

Full Text Available NAC proteins constitute one of the largest groups of plant-specific transcription factors and are known to play essential roles in various developmental processes. They are also important in plant responses to stresses such as drought, soil salinity, cold, and heat, which adversely affect growth. The current knowledge regarding the distribution of NAC proteins in plant lineages comes from relatively small samplings from the available data. In the present study, we broadened the number of plant species containing the NAC family origin and evolution to shed new light on the evolutionary history of this family in angiosperms. A comparative genome analysis was performed on 24 land plant species, and NAC ortholog groups were identified by means of bidirectional BLAST hits. Large NAC gene families are found in those species that have experienced more whole-genome duplication events, pointing to an expansion of the NAC family with divergent functions in flowering plants. A total of 3,187 NAC transcription factors that clustered into six major groups were used in the phylogenetic analysis. Many orthologous groups were found in the monocot and eudicot lineages, but only five orthologous groups were found between P. patens and each representative taxa of flowering plants. These groups were called basal orthologous groups and likely expanded into more recent taxa to cope with their environmental needs. This analysis on the angiosperm NAC family represents an effort to grasp the evolutionary and functional diversity within this gene family while providing a basis for further functional research on vascular plant gene families.

Mice lacking pituitary tumor transforming gene show elevated exposure of DGalNAc carbohydrate determinants

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Lutsyk A. D.

2012-04-01

Full Text Available Aim. To investigate the influence of pituitary tumor transforming gene (pttg-1 knockout on glycome of parenchimal organs by means of lectin histochemistry. Methods. DGalNAc, DGlcNAc, NeuNAc carbohydrate determinants were labelled with soybean agglutinin (SBA and wheat germ agglutinin (WGA, conjugated to peroxidase, with subsequent visualization of the lectin-binding sites with diaminobenzidine. The testes and kidneys of murine strain BL6/C57 with the pttg-1 gene knockout (PTTG-KO were compared to the wild type (PTTG-WT animals, both groups 1 month of age. Results. Knockout of the pttg-1 gene was accompanied by enhanced exposure of the DGalNAc sugar residues within the Golgi complex of secondary spermatocytes, in a brush border of renal tubules and on the lumenal surface of collecting ducts. Conclusions. This study suggests that knockout of the pttg-1 gene may lead to the changes in carbohydrate processing in mammalian organism.

The NAC transcription factor family in maritime pine (Pinus Pinaster): molecular regulation of two genes involved in stress responses.

Science.gov (United States)

Pascual, Ma Belén; Cánovas, Francisco M; Ávila, Concepción

2015-10-24

NAC transcription factors comprise a large plant-specific gene family involved in the regulation of diverse biological processes. Despite the growing number of studies on NAC transcription factors in various species, little information is available about this family in conifers. The goal of this study was to identify the NAC transcription family in maritime pine (Pinus pinaster), to characterize ATAF-like genes in response to various stresses and to study their molecular regulation. We have isolated two maritime pine NAC genes and using a transient expression assay in N. benthamiana leaves estudied the promoter jasmonate response. In this study, we identified 37 NAC genes from maritime pine and classified them into six main subfamilies. The largest group includes 12 sequences corresponding to stress-related genes. Two of these NAC genes, PpNAC2 and PpNAC3, were isolated and their expression profiles were examined at various developmental stages and in response to various types of stress. The expression of both genes was strongly induced by methyl jasmonate (MeJA), mechanical wounding, and high salinity. The promoter regions of these genes were shown to contain cis-elements involved in the stress response and plant hormonal regulation, including E-boxes, which are commonly found in the promoters of genes that respond to jasmonate, and binding sites for bHLH proteins. Using a transient expression assay in N. benthamiana leaves, we found that the promoter of PpNAC3 was rapidly induced upon MeJA treatment, while this response disappeared in plants in which the transcription factor NbbHLH2 was silenced. Our results suggest that PpNAC2 and PpNAC3 encode stress-responsive NAC transcription factors involved in the jasmonate response in pine. Furthermore, these data also suggest that the jasmonate signaling pathway is conserved between angiosperms and gymnosperms. These findings may be useful for engineering stress tolerance in pine via biotechnological approaches.

Ammonia chemistry at SMART

International Nuclear Information System (INIS)

Na, J. W.; Seong, G. W.; Lee, E. H.; Kim, W. C.; Choi, B. S.; Kim, J. P.; Lee, D. J.

1999-01-01

Ammonia is used as the pH control agent of primary water at SMART (System-integrated Modular Advanced ReacTor). Some of this ammonia is decomposed to hydrogen and nitrogen by radiation in the reactor core. The produced hydrogen gas is used for the removal of dissolved oxygen in the coolant. Some of nitrogen gas in pressurizer is dissolved into the primary water. Because ammonia, hydrogen and nitrogen which is produced by ammonia radiolysis are exist in the coolant at SMART, ammonia chemistry at SMART is different with lithium-boron chemistry at commercial PWR. In this study, the pH characteristics of ammonia and the solubility characteristics of hydrogen and nytrogen were analyzed for the management of primary water chemistry at SMART

CDX2 homeoprotein is involved in the regulation of ST6GalNAc-I gene in intestinal metaplasia

DEFF Research Database (Denmark)

Pinto, Rita; Barros, Rita; Pereira-Castro, Isabel

2015-01-01

lesions and in the intestine, CDX2 homeobox transcription factor is co-expressed with STn and ST6GalNAc-I. We therefore hypothesized that CDX2 might induce STn expression by positive regulation of ST6GalNAc-I. We showed that ST6GalNAc-I transcript levels and CDX2 have a coordinated expression upon Caco-2...... in vitro differentiation, and overexpression of CDX2 in MKN45 gastric cells increases ST6GalNAc-I transcript levels. Nine putative CDX-binding sites in the ST6GalNAc-I-regulatory sequence were identified and analyzed by chromatin immunoprecipitation in Caco-2 cells and in IM. The results showed that CDX2...... protein is recruited to all regions, being the most proximal sites preferentially occupied in vivo. Luciferase assays demonstrated that CDX2 is able to transactivate ST6GalNac-I-regulatory region. The induction was stronger for the regions mapped in the neighbourhood of ATG start codon and site...

Interaction of a novel Tn (GalNAc alpha 1-->Ser/Thr) glycoprotein with Gal, GalNAc and GlcNAc specific lectins.

Science.gov (United States)

Wu, A M; Wu, J H; Shen, F

1994-01-14

A naturally occurring Tn glycoprotein (Native ASG-Tn) with GalNAc alpha 1-->Ser/Thr as the only carbohydrate side chains, has been prepared from armadillo submandibular glands. In a quantitative precipitin assay, this glycoprotein completely precipitated Maclura pomifera (MPA), Vicia villosa B4 (VVL-B4) and Artocarpus integrifolia (Jacalin, AIL). It also reacted well with Helix pomatia (HPL) and Wistaria floribunda (WFL) and precipitated over 75% of the lectin nitrogen added, but poorly with Ricinus communis agglutinin (RCA1), ricin, peanut (Arachis hypogaea, PNA), Abrus precatorius agglutinin (APA) and Triticum vulgaris (WGA). This finding suggests that this novel Tn-glycoprotein may serve as a useful reagent for differentiating Tn and T specific monoclonal antibodies and lectins.

Foreword of the Fifth Symposium on Nuclear Analytical Chemistry (NAC-V)

International Nuclear Information System (INIS)

Acharya, R.; Goswami, A.; Reddy, A.V.R.

2014-01-01

The Fifth Symposium on Nuclear Analytical Chemistry (NAC-V) was organized at BARC, Mumbai during January 20-24, 2014 with more than 300 participants. It was sponsored by the Board of Research in Nuclear Sciences, Department of Atomic Energy (DAE), India and organized in cooperation with the IAEA and coorganized by the IANCAS. A total of 240 contributed abstracts along with 27 invited talks and 10 invited short talks were presented in 15 technical sessions. Selected 54 full papers of NAC-V have been accepted after review for publication in special issue of JRNC. (author)

A Systematic Study of Site-specific GalNAc-type O-Glycosylation Modulating Proprotein Convertase Processing

DEFF Research Database (Denmark)

Schjoldager, Katrine Ter-Borch Gram; Vester-Christensen, Malene B.; Goth, Christoffer K.

2011-01-01

Site-specific GalNAc-type O-glycosylation is emerging as an important co-regulator of proprotein convertase (PC) processing of proteins. PC processing is crucial in regulating many fundamental biological pathways and O-glycans in or immediately adjacent to processing sites may affect recognition...... and function of PCs. Thus, we previously demonstrated that deficiency in site-specific O-glycosylation in a PC site of the fibroblast growth factor, FGF23, resulted in marked reduction in secretion of active unprocessed FGF23, which cause familial tumoral calcinosis and hyperostosis hyperphosphatemia. GalNAc......-type O-glycosylation is found on serine and threonine amino acids and up to 20 distinct polypeptide GalNAc transferases catalyze the first addition of GalNAc to proteins making this step the most complex and differentially regulated steps in protein glycosylation. There is no reliable prediction model...

Chemical Arsenal for the Study of O-GlcNAc

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Eun J. Kim

2011-02-01

Full Text Available The concepts of both protein glycosylation and cellular signaling have been influenced by O-linked-β-N-acetylglucosamine (O-GlcNAc modification (O-GlcNAcylation on the hydroxyl group of serine or threonine residues. Unlike conventional protein glycosylation, O-GlcNAcylation is localized in the nucleocytoplasm and its cycling is a dynamic process that operates in a highly regulated manner in response to various cellular stimuli. These characteristics render O-GlcNAcylation similar to phosphorylation, which has long been considered a major regulatory mechanism in cellular processes. Various efficient chemical approaches and novel mass spectrometric (MS techniques have uncovered numerous O-GlcNAcylated proteins that are involved in the regulation of many important cellular events. These discoveries imply that O-GlcNAcylation is another major regulator of cellular signaling. However, in contrast to phosphorylation, which is regulated by hundreds of kinases and phosphatases, dynamic O-GlcNAc cycling is catalyzed by only two enzymes: uridine diphospho-N-acetyl-glucosamine:polypeptide β-N-acetylglucosaminyl transferase (OGT and β-D-N-acetylglucosaminidase (OGA. Many useful chemical tools have recently been used to greatly expand our understanding of the extensive crosstalk between O-GlcNAcylation and phosphorylation and hence of cellular signaling. This review article describes the various useful chemical tools that have been developed and discusses the considerable advances made in the O-GlcNAc field.

The ubiquitin ligase SEVEN IN ABSENTIA (SINA) ubiquitinates a defense-related NAC transcription factor and is involved in defense signaling.

Science.gov (United States)

Miao, Min; Niu, Xiangli; Kud, Joanna; Du, Xinran; Avila, Julian; Devarenne, Timothy P; Kuhl, Joseph C; Liu, Yongsheng; Xiao, Fangming

2016-07-01

We recently identified a defense-related tomato (Solanum lycopersicum) NAC (NAM, ATAF1,2, CUC2) transcription factor, NAC1, that is subjected to ubiquitin-proteasome system-dependent degradation in plant cells. In this study, we identified a tomato ubiquitin ligase (termed SEVEN IN ABSENTIA3; SINA3) that ubiquitinates NAC1, promoting its degradation. We conducted coimmunoprecipitation and bimolecular fluorescence complementation to determine that SINA3 specifically interacts with the NAC1 transcription factor in the nucleus. Moreover, we found that SINA3 ubiquitinates NAC1 in vitro and promotes NAC1 degradation via polyubiquitination in vivo, indicating that SINA3 is a ubiquitin ligase that ubiquitinates NAC1, promoting its degradation. Our real-time PCR analysis indicated that, in contrast to our previous finding that NAC1 mRNA abundance increases upon Pseudomonas infection, the SINA3 mRNA abundance decreases in response to Pseudomonas infection. Moreover, using Agrobacterium-mediated transient expression, we found that overexpression of SINA3 interferes with the hypersensitive response cell death triggered by multiple plant resistance proteins. These results suggest that SINA3 ubiquitinates a defense-related NAC transcription factor for degradation and plays a negative role in defense signaling. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Effects of pore sizes and oxygen-containing functional groups on desulfurization activity of Fe/NAC prepared by ultrasonic-assisted impregnation

International Nuclear Information System (INIS)

Shu, Song; Guo, Jia-Xiu; Liu, Xiao-Li; Wang, Xue-Jiao; Yin, Hua-Qiang; Luo, De-Ming

2016-01-01

Graphical abstract: - Highlights: • Fe/NAC-60 exhibits the best desulfurization activity. • Different oscillation time can change surface area and pore volume of catalysts. • Ultrasonic oscillation increases Fe dispersion on carrier and effective pores. • Pore sizes play a crucial role during the SO 2 removal. - Abstract: A series of Fe-loaded activated carbons treated by HNO 3 (Fe/NAC) were prepared by incipient impregnation method with or without ultrasonic assistance and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy with energy disperse spectroscope (SEM-EDS), transmission electron microscopy (TEM) and N 2 adsorption/desorption. The desulfurization activities were evaluated at a fixed bed reactor under a mixed gas simulated from flue gas. The results showed that desulfurization activity from excellent to poor is as follows: Fe/NAC-60 > Fe/NAC-80 > Fe/NAC-30 > Fe/NAC-15 > Fe/NAC-0 > Fe/NAC-100 > NAC. Fe/NAC-60 exhibits the best desulfurization activity and has breakthrough sulfur capacity of 319 mg/g and breakthrough time of 540 min. The introduction of ultrasonic oscillation does not change the form of Fe oxides on activated carbon but can change the dispersion and relative contents of Fe 3 O 4 . The types of oxygen-containing functional groups have no obvious change for all samples but the texture properties show some differences when they are oscillated for different times. The fresh Fe/NAC-60 has a surface area of 1045 m 2 /g and total pore volume of 0.961 cm 3 /g with micropore volume of 0.437 cm 3 /g and is larger than Fe/NAC-0 (823 m 2 /g, 0.733 and 0.342 cm 3 /g). After desulfurization, surface area and pore volume of all samples decrease significantly, and those of the exhausted Fe/NAC-60 decrease to 233 m 2 /g and 0.481 cm 3 /g, indicating that some byproducts deposit on surface to cover pores. Pore size distribution influences SO 2 adsorption, and fresh Fe/NAC-60 has

Theoretical pKa prediction of the α-phosphate moiety of uridine 5‧-diphosphate-GlcNAc

Science.gov (United States)

Vipperla, Bhavaniprasad; Griffiths, Thomas M.; Wang, Xingyong; Yu, Haibo

2017-01-01

The pKa value of the α-phosphate moiety of uridine 5‧-diphosphate-GlcNAc (UDP-GlcNAc) has been successfully calculated using density functional theory methods in conjunction with the Polarizable Continuum Models. Theoretical methods were benchmarked over a dataset comprising of alkyl phosphates. B3LYP/6-31+G(d,p) calculations using SMD solvation model provide excellent agreement with the experimental data. The predicted pKa for UDP-GlcNAc is consistent with most recent NMR studies but much higher than what it has long been thought to be. The importance of this study is evident that the predicted pKa for UDP-GlcNAc supports its potential role as a catalytic base in the substrate-assisted biocatalysis.

Texture analysis on MR images helps predicting non-response to NAC in breast cancer

International Nuclear Information System (INIS)

Michoux, N.; Van den Broeck, S.; Lacoste, L.; Fellah, L.; Galant, C.; Berlière, M.; Leconte, I.

2015-01-01

To assess the performance of a predictive model of non-response to neoadjuvant chemotherapy (NAC) in patients with breast cancer based on texture, kinetic, and BI-RADS parameters measured from dynamic MRI. Sixty-nine patients with invasive ductal carcinoma of the breast who underwent pre-treatment MRI were studied. Morphological parameters and biological markers were measured. Pathological complete response was defined as the absence of invasive and in situ cancer in breast and nodes. Pathological non-responders, partial and complete responders were identified. Dynamic imaging was performed at 1.5 T with a 3D axial T1W GRE fat-suppressed sequence. Visual texture, kinetic and BI-RADS parameters were measured in each lesion. ROC analysis and leave-one-out cross-validation were used to assess the performance of individual parameters, then the performance of multi-parametric models in predicting non-response to NAC. A model based on four pre-NAC parameters (inverse difference moment, GLN, LRHGE, wash-in) and k-means clustering as statistical classifier identified non-responders with 84 % sensitivity. BI-RADS mass/non-mass enhancement, biological markers and histological grade did not contribute significantly to the prediction. Pre-NAC texture and kinetic parameters help predicting non-benefit to NAC. Further testing including larger groups of patients with different tumor subtypes is needed to improve the generalization properties and validate the performance of the predictive model

Genome-wide survey and expression analysis of the plant-specific NAC transcription factor family in soybean during development and dehydration stress.

Science.gov (United States)

Le, Dung Tien; Nishiyama, Rie; Watanabe, Yasuko; Mochida, Keiichi; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo; Tran, Lam-Son Phan

2011-08-01

Plant-specific NAC transcription factors (TFs) play important roles in regulating diverse biological processes, including development, senescence, growth, cell division and responses to environmental stress stimuli. Within the soybean genome, we identified 152 full-length GmNAC TFs, including 11 membrane-bound members. In silico analysis of the GmNACs, together with their Arabidopsis and rice counterparts, revealed similar NAC architecture. Next, we explored the soybean Affymetrix array and Illumina transcriptome sequence data to analyse tissue-specific expression profiles of GmNAC genes. Phylogenetic analysis using stress-related NAC TFs from Arabidopsis and rice as seeding sequences identified 58 of the 152 GmNACs as putative stress-responsive genes, including eight previously reported dehydration-responsive GmNACs. We could design gene-specific primers for quantitative real-time PCR verification of 38 out of 50 newly predicted stress-related genes. Twenty-five and six GmNACs were found to be induced and repressed 2-fold or more, respectively, in soybean roots and/or shoots in response to dehydration. GmNAC085, whose amino acid sequence was 39%; identical to that of well-known SNAC1/ONAC2, was the most induced gene upon dehydration, showing 390-fold and 20-fold induction in shoots and roots, respectively. Our systematic analysis has identified excellent tissue-specific and/or dehydration-responsive candidate GmNAC genes for in-depth characterization and future development of improved drought-tolerant transgenic soybeans.

F44. AN ADD-ON TRIAL WITH N-ACETYL-CYSTEINE (NAC) IN EARLY PSYCHOSIS PATIENTS: TOWARDS BIOMARKER GUIDED TREATMENT

Science.gov (United States)

Conus, Philippe; Fournier, Margot; Xin, Lijing; Cleusix, Martine; Baumann, Philipp S; Ferrari, Carina; Cousins, Ann; Alameda, Luis; Gholam-Razaee, Mehdi; Golay, Philippe; Jenni, Raoul; Woo, Tsung-Ung Wilson; Keshavan, Matcheri; Eap, Chin B; Wojcik, Joanne; Cuenod, Michel; Buclin, Thierry; Gruetter, Rolf; Seidman, Larry; Do, Kim

2018-01-01

Abstract Background Oxidative stress, coupled with dysregulation of inflammation, NMDAR and dopamine, is involved in schizophrenia (SZ) pathophysiology. Earlier add-on clinical trials showed in chronic SZ patients that NAC, a precursor of glutathione (GSH), an important cerebral antioxidant, improved negative symptoms, mismatch negativity and local synchronization. We hypothesized that NAC at an earlier stage of illness would have a greater impact. Methods Early psychosis patients (EP, less than 5 years of illness, N=63; NAC=32, placebo=31) were supplemented with NAC (2.7g/day, 6 months) in a double-blind randomized placebo-controlled trial. Outcome measures: PANSS and neurocognition (MATRICS Consensus Cognitive Battery; n=36); quantification of medial prefronfal cortex glutathione (GSHmPFC) by 1H-magnetic-resonance-spectroscopy, of white matter diffusion properties estimated by generalized fractional anisotropy (gFA) computed from diffusion spectrum imaging (DSI), of blood cells GSH (GSHBC) and GSH peroxidase activity (GPxBC) at start and end of trial Results While PANSS negative and positive were not affected by NAC, NAC improved Processing Speed (NAC > Placebo; F(1, 30)=5.849, p=.022), favoring 2 of 3 processing speed tasks (Trail Making A, F(1, 30)=4.279, p=.048 & Verbal Fluency, F(1, 30)=5.749, p=.023). GSHmPFC (+23%, p=0.005) and GSHBC (+19%, p=0.05) were increased following NAC treatment. In patients with high-baseline GPxBC (>22.3U/gHb), subgroup explorations revealed an improvement of PANSS positive compared to placebo (p=0.02). The change of PANSS positive correlated negatively with that of GPxBC activity, showing that the improvement paralleled the restoration of redox status. NAC group showed 11% increase in fornix white matter integrity as measured by gFA, correlating with an increase in GSHmPFC over the 6-months period. Discussion This is the first clinical trial assessing the impact of NAC treatment in a sample of EP and the potential predictive role

Liberation of ammonia by cyanobacteria

Energy Technology Data Exchange (ETDEWEB)

Newton, J.W.

1986-04-01

Photoheterotrophic nitrogen-fixing cyanobacteria release ammonia when treated with methionine sulfoximine (MSX) to inhibit nitrogen incorporation into protein. This released ammonia can be derived from recently fixed nitrogen (nitrogen atmosphere) or endogenous reserves (argon atmosphere). Anaerobic ammonia release requires light and is stimulated by the photosystem II herbicides DCMU and Atrazine, regardless of the source of ammonia. As much as one quarter of the total cellular nitrogen can be released as ammonia by cyanbacteria treated with MSX and DCMU under argon in light. Chromatography of cell extracts indicates that virtually all cellular proteins are degraded. DCMU and Atrazine, at very low concentration, inhibit sustained uptake of the ammonia analog /sup 14/C methylamine. These data indicate that the herbicides interrupt ammonia uptake and retention by the cells, and support a role for photosystem II in ammonia metabolism.

Liberation of ammonia by cyanobacteria

International Nuclear Information System (INIS)

Newton, J.W.

1986-01-01

Photoheterotrophic nitrogen-fixing cyanobacteria release ammonia when treated with methionine sulfoximine (MSX) to inhibit nitrogen incorporation into protein. This released ammonia can be derived from recently fixed nitrogen (nitrogen atmosphere) or endogenous reserves (argon atmosphere). Anaerobic ammonia release requires light and is stimulated by the photosystem II herbicides DCMU and Atrazine, regardless of the source of ammonia. As much as one quarter of the total cellular nitrogen can be released as ammonia by cyanbacteria treated with MSX and DCMU under argon in light. Chromatography of cell extracts indicates that virtually all cellular proteins are degraded. DCMU and Atrazine, at very low concentration, inhibit sustained uptake of the ammonia analog 14 C methylamine. These data indicate that the herbicides interrupt ammonia uptake and retention by the cells, and support a role for photosystem II in ammonia metabolism

75 FR 57841 - List of Approved Spent Fuel Storage Casks: NAC-MPC System, Revision 6, Confirmation of Effective...

Science.gov (United States)

2010-09-23

... Spent Fuel Storage Casks: NAC-MPC System, Revision 6, Confirmation of Effective Date AGENCY: Nuclear... amended the NRC's spent fuel storage regulations at 10 CFR 72.214 to revise the NAC-MPC System listing to... configuration of the NAC-MPC storage system by the incorporation of a single closure lid with a welded closure...

Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

Science.gov (United States)

Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

2016-01-01

Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia. We measured breath ammonia in real time by quartz enhanced photoacoustic spectrometry and blood ammonia in 10 healthy and 10 cirrhotic participants. Each participant contributed 5 breath samples and blood for ammonia measurement within 1 h. We calculated the coefficient of variation (CV) for 5 breath ammonia values, reported medians of healthy and cirrhotic participants, and used scatterplots to display breath and blood ammonia. For healthy participants, mean age was 22 years (±4), 70% were men, and body mass index (BMI) was 27 (±5). For cirrhotic participants, mean age was 61 years (±8), 60% were men, and BMI was 31 (±7). Median blood ammonia for healthy participants was within normal range, 10 μmol L−1 (interquartile range (IQR), 3–18) versus 46 μmol L−1 (IQR, 23–66) for cirrhotic participants. Median breath ammonia was 379 pmol mL−1 CO2 (IQR, 265–765) for healthy versus 350 pmol mL−1 CO2 (IQR, 180–1013) for cirrhotic participants. CV was 17 ± 6%. There remains an important unmet need in the evaluation of systemic ammonia, and breath measurement continues to demonstrate promise to fulfill this need. Given the many differences between breath and blood ammonia measurement, we examined biological explanations for our findings in healthy and cirrhotic participants. We conclude that based upon these preliminary data breath may offer clinically important information this is not provided by blood ammonia. PMID:26658550

Mutations in N-acetylglucosamine (O-GlcNAc) transferase in patients with X-linked intellectual disability

NARCIS (Netherlands)

Willems, A.P.; Gundogdu, M.; Kempers, M.J.E.; Giltay, J.C.; Pfundt, R.P.; Elferink, M.; Loza, B.F.; Fuijkschot, J.; Ferenbach, A.T.; Gassen, K.L. van; Aalten, D.M.F. van; Lefeber, D.J.

2017-01-01

N-Acetylglucosamine (O-GlcNAc) transferase (OGT) regulates protein O-GlcNAcylation, an essential and dynamic post-translational modification. The O-GlcNAc modification is present on numerous nuclear and cytosolic proteins and has been implicated in essential cellular functions such as signaling and

Effects of pore sizes and oxygen-containing functional groups on desulfurization activity of Fe/NAC prepared by ultrasonic-assisted impregnation

Energy Technology Data Exchange (ETDEWEB)

Shu, Song [College of Architecture and Environment, Sichuan University, Chengdu 610065, Sichuan (China); Guo, Jia-Xiu, E-mail: guojiaxiu@scu.edu.cn [College of Architecture and Environment, Sichuan University, Chengdu 610065, Sichuan (China); National Engineering Technology Research Center for Flue Gas Desulfurization, Chengdu 610065, Sichuan (China); Sichuan Provincial Environmental Protection Environmental Catalysis and Materials Engineering Technology Center, Chengdu 610065, Sichuan (China); Liu, Xiao-Li [National Engineering Technology Research Center for Flue Gas Desulfurization, Chengdu 610065, Sichuan (China); Wang, Xue-Jiao [College of Architecture and Environment, Sichuan University, Chengdu 610065, Sichuan (China); Yin, Hua-Qiang [College of Architecture and Environment, Sichuan University, Chengdu 610065, Sichuan (China); National Engineering Technology Research Center for Flue Gas Desulfurization, Chengdu 610065, Sichuan (China); Sichuan Provincial Environmental Protection Environmental Catalysis and Materials Engineering Technology Center, Chengdu 610065, Sichuan (China); Luo, De-Ming [National Engineering Technology Research Center for Flue Gas Desulfurization, Chengdu 610065, Sichuan (China)

2016-01-01

Graphical abstract: - Highlights: • Fe/NAC-60 exhibits the best desulfurization activity. • Different oscillation time can change surface area and pore volume of catalysts. • Ultrasonic oscillation increases Fe dispersion on carrier and effective pores. • Pore sizes play a crucial role during the SO{sub 2} removal. - Abstract: A series of Fe-loaded activated carbons treated by HNO{sub 3} (Fe/NAC) were prepared by incipient impregnation method with or without ultrasonic assistance and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy with energy disperse spectroscope (SEM-EDS), transmission electron microscopy (TEM) and N{sub 2} adsorption/desorption. The desulfurization activities were evaluated at a fixed bed reactor under a mixed gas simulated from flue gas. The results showed that desulfurization activity from excellent to poor is as follows: Fe/NAC-60 > Fe/NAC-80 > Fe/NAC-30 > Fe/NAC-15 > Fe/NAC-0 > Fe/NAC-100 > NAC. Fe/NAC-60 exhibits the best desulfurization activity and has breakthrough sulfur capacity of 319 mg/g and breakthrough time of 540 min. The introduction of ultrasonic oscillation does not change the form of Fe oxides on activated carbon but can change the dispersion and relative contents of Fe{sub 3}O{sub 4}. The types of oxygen-containing functional groups have no obvious change for all samples but the texture properties show some differences when they are oscillated for different times. The fresh Fe/NAC-60 has a surface area of 1045 m{sup 2}/g and total pore volume of 0.961 cm{sup 3}/g with micropore volume of 0.437 cm{sup 3}/g and is larger than Fe/NAC-0 (823 m{sup 2}/g, 0.733 and 0.342 cm{sup 3}/g). After desulfurization, surface area and pore volume of all samples decrease significantly, and those of the exhausted Fe/NAC-60 decrease to 233 m{sup 2}/g and 0.481 cm{sup 3}/g, indicating that some byproducts deposit on surface to cover pores. Pore size distribution

Effects of chronic ammonia exposure on ammonia metabolism and excretion in marine medaka Oryzias melastigma.

Science.gov (United States)

Gao, Na; Zhu, Limei; Guo, Zhiqiang; Yi, Meisheng; Zhang, Li

2017-06-01

Ammonia is highly toxic to aquatic organisms, but whether ammonia excretion or ammonia metabolism to less toxic compounds is the major strategy for detoxification in marine fish against chronic ammonia exposure is unclear to date. In this study, we investigated the metabolism and excretion of ammonia in marine medaka Oryzias melastigma during chronic ammonia exposure. The fish were exposed to 0, 0.1, 0.3, 0.6, and 1.1 mmol l -1  NH 4 Cl spiked seawater for 8 weeks. Exposure of 0.3-1.1 mmol l -1  NH 4 Cl had deleterious effects on the fish, including significant reductions in growth, feed intake, and total protein content. However, the fish could take strategies to detoxify ammonia. The tissue ammonia (T Amm ) in the 0.3-1.1 mmol l -1  NH 4 Cl treatments was significantly higher than those in the 0 and 0.1 mmol l -1  NH 4 Cl treatments after 2 weeks of exposure, but it recovered with prolonged exposure time, ultimately reaching the control level after 8 weeks. The amino acid catabolic rate decreased to reduce the gross ammonia production with the increasing ambient ammonia concentration. The concentrations of most metabolites remained constant in the 0-0.6 mmol l -1  NH 4 Cl treatments, whereas 5 amino acids and 3 energy metabolism-related metabolites decreased in the 1.1 mmol l -1  NH 4 Cl treatment. J Amm steadily increased in ambient ammonia from 0 to 0.6 mmol l -1 and slightly decreased when the ambient ammonia concentration increased to 1.1 mmol l -1 . Overall, marine medaka cope with sublethal ammonia environment by regulating the tissue T Amm via reducing the ammonia production and increasing ammonia excretion. Copyright © 2017 Elsevier Ltd. All rights reserved.

DETERMINATION OF AMMONIA IN EAR-LOBE CAPILLARY BLOOD IS AN ALTERNATIVE TO ARTERIAL BLOOD AMMONIA

NARCIS (Netherlands)

HUIZENGA, [No Value; GIPS, CH; CONN, HO; JANSEN, PLM

1995-01-01

Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

Determination of ammonia in ear-lobe capillary blood is an alternative to arterial blood ammonia

NARCIS (Netherlands)

Huizenga, J. R.; Gips, C. H.; Conn, H. O.; Jansen, P. L.

1995-01-01

Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

Identification of GIG1, a GlcNAc-induced gene in Candida albicans needed for normal sensitivity to the chitin synthase inhibitor nikkomycin Z.

Science.gov (United States)

Gunasekera, Angelo; Alvarez, Francisco J; Douglas, Lois M; Wang, Hong X; Rosebrock, Adam P; Konopka, James B

2010-10-01

The amino sugar N-acetylglucosamine (GlcNAc) is known to be an important structural component of cells from bacteria to humans, but its roles in cell signaling are less well understood. GlcNAc induces two pathways in the human fungal pathogen Candida albicans. One activates cyclic AMP (cAMP) signaling, which stimulates the formation of hyphal cells and the expression of virulence genes, and the other pathway induces genes needed to catabolize GlcNAc. Microarray analysis of gene expression was carried out under four different conditions in order to characterize the transcriptional changes induced by GlcNAc. The most highly induced genes include those that encode a GlcNAc transporter (NGT1) and the GlcNAc catabolic enzymes (HXK1, DAC1, and NAG1). GlcNAc also activated most of the genes whose expression is increased when cells are triggered with other stimuli to form hyphae. Surprisingly, GlcNAc also induced a subset of genes that are regulated by galactose (GAL1, GAL7, and GAL10), which may be due to cross talk between signaling pathways. A novel GlcNAc-induced gene, GIG1, which is not essential for GlcNAc catabolism or the induction of hyphae, was identified. However, a Gig1-green fluorescent protein (GFP) fusion protein was specifically induced by GlcNAc, and not by other sugars. Gig1-GFP localized to the cytoplasm, where GlcNAc metabolism occurs. Significantly, a gig1Δ mutant displayed increased resistance to nikkomycin Z, which inhibits chitin synthase from converting UDP-GlcNAc into cell wall chitin. Gig1 is highly conserved in fungi, especially those that contain GlcNAc catabolic genes. These results implicate Gig1 in GlcNAc metabolism.

De novo expression of human polypeptide N-acetylgalactosaminyltransferase 6 (GalNAc-T6) in colon adenocarcinoma inhibits the differentiation of colonic epithelium

DEFF Research Database (Denmark)

Lavrsen, Kirstine; Dabelsteen, Sally; Vakhrushev, Sergey Y

2018-01-01

Aberrant expression of O-glycans is a hallmark of epithelial cancers. Mucin type O-glycosylation is initiated by a large family of UDP-GalNAc:polypeptide N-acetyl-galactosaminyltransferases (GalNAc-Ts), that target different proteins and are differentially expressed in cells and organs. Here we...... investigated the expression patterns of all of the GalNAc-Ts in colon cancer by analysing transcriptomic data. We found that GalNAc-T6 was highly upregulated in colon adenocarcinomas but absent in normal-appearing adjacent colon tissue. The results were verified by immunohistochemistry, suggesting that Gal......NAc-T6 plays a role in colon carcinogenesis. To investigate the function of GalNAc-T6 in colon cancer, we used precise gene targeting to produce isogenic colon cancer cell lines with a knockout/-rescue system for GalNAc-T6. GalNAc-T6 expression was associated with a cancer-like, dysplastic growth pattern...

Comparison of fouling characteristics in different pore-sized submerged ceramic membrane bioreactors.

Science.gov (United States)

Jin, Le; Ong, Say Leong; Ng, How Yong

2010-12-01

Membrane fouling, the key disadvantage that inevitably occurs continuously in the membrane bioreactor (MBR), baffles the wide-scale application of MBR. Ceramic membrane, which possesses high chemical and thermal resistance, has seldom been used in MBR to treat municipal wastewater. Four ceramic membranes with the same materials but different pore sizes, ranging from 80 to 300 nm, were studied in parallel using four lab-scale submerged MBRs (i.e., one type of ceramic membrane in one MBR). Total COD and ammonia nitrogen removal efficiencies were observed to be consistently above 94.5 and 98%, respectively, in all submerged ceramic membrane bioreactors. The experimental results showed that fouling was mainly affected by membrane's microstructure, surface roughness and pore sizes. Ceramic membrane with the roughest surface and biggest pore size (300 nm) had the highest fouling potential with respect to the TMP profile. The 80 nm membrane with a smoother surface and relatively uniform smaller pore openings experienced least membrane fouling with respect to TMP increase. The effects of the molecular weight distribution, particle size distribution and other biomass characteristics such as extracellular polymeric substances, zeta potential and capillary suction time, were also investigated in this study. Results showed that no significant differences of these attributes were observed. These observations indicate that the membrane surface properties are the dominant factors leading to different fouling potential in this study. Copyright © 2010 Elsevier Ltd. All rights reserved.

Precision 3d Surface Reconstruction from Lro Nac Images Using Semi-Global Matching with Coupled Epipolar Rectification

Science.gov (United States)

Hu, H.; Wu, B.

2017-07-01

The Narrow-Angle Camera (NAC) on board the Lunar Reconnaissance Orbiter (LRO) comprises of a pair of closely attached high-resolution push-broom sensors, in order to improve the swath coverage. However, the two image sensors do not share the same lenses and cannot be modelled geometrically using a single physical model. Thus, previous works on dense matching of stereo pairs of NAC images would generally create two to four stereo models, each with an irregular and overlapping region of varying size. Semi-Global Matching (SGM) is a well-known dense matching method and has been widely used for image-based 3D surface reconstruction. SGM is a global matching algorithm relying on global inference in a larger context rather than individual pixels to establish stable correspondences. The stereo configuration of LRO NAC images causes severe problem for image matching methods such as SGM, which emphasizes global matching strategy. Aiming at using SGM for image matching of LRO NAC stereo pairs for precision 3D surface reconstruction, this paper presents a coupled epipolar rectification methods for LRO NAC stereo images, which merges the image pair in the disparity space and in this way, only one stereo model will be estimated. For a stereo pair (four) of NAC images, the method starts with the boresight calibration by finding correspondence in the small overlapping stripe between each pair of NAC images and bundle adjustment of the stereo pair, in order to clean the vertical disparities. Then, the dominate direction of the images are estimated by project the center of the coverage area to the reference image and back-projected to the bounding box plane determined by the image orientation parameters iteratively. The dominate direction will determine an affine model, by which the pair of NAC images are warped onto the object space with a given ground resolution and in the meantime, a mask is produced indicating the owner of each pixel. SGM is then used to generate a disparity

PRECISION 3D SURFACE RECONSTRUCTION FROM LRO NAC IMAGES USING SEMI-GLOBAL MATCHING WITH COUPLED EPIPOLAR RECTIFICATION

Directory of Open Access Journals (Sweden)

H. Hu

2017-07-01

Full Text Available The Narrow-Angle Camera (NAC on board the Lunar Reconnaissance Orbiter (LRO comprises of a pair of closely attached high-resolution push-broom sensors, in order to improve the swath coverage. However, the two image sensors do not share the same lenses and cannot be modelled geometrically using a single physical model. Thus, previous works on dense matching of stereo pairs of NAC images would generally create two to four stereo models, each with an irregular and overlapping region of varying size. Semi-Global Matching (SGM is a well-known dense matching method and has been widely used for image-based 3D surface reconstruction. SGM is a global matching algorithm relying on global inference in a larger context rather than individual pixels to establish stable correspondences. The stereo configuration of LRO NAC images causes severe problem for image matching methods such as SGM, which emphasizes global matching strategy. Aiming at using SGM for image matching of LRO NAC stereo pairs for precision 3D surface reconstruction, this paper presents a coupled epipolar rectification methods for LRO NAC stereo images, which merges the image pair in the disparity space and in this way, only one stereo model will be estimated. For a stereo pair (four of NAC images, the method starts with the boresight calibration by finding correspondence in the small overlapping stripe between each pair of NAC images and bundle adjustment of the stereo pair, in order to clean the vertical disparities. Then, the dominate direction of the images are estimated by project the center of the coverage area to the reference image and back-projected to the bounding box plane determined by the image orientation parameters iteratively. The dominate direction will determine an affine model, by which the pair of NAC images are warped onto the object space with a given ground resolution and in the meantime, a mask is produced indicating the owner of each pixel. SGM is then used to

Methods for the Detection, Study, and Dynamic Profiling of O-GlcNAc Glycosylation.

Science.gov (United States)

Thompson, John W; Griffin, Matthew E; Hsieh-Wilson, Linda C

2018-01-01

The addition of O-linked β-N-acetylglucosamine (O-GlcNAc) to serine/threonine residues of proteins is a ubiquitous posttranslational modification found in all multicellular organisms. Like phosphorylation, O-GlcNAc glycosylation (O-GlcNAcylation) is inducible and regulates a myriad of physiological and pathological processes. However, understanding the diverse functions of O-GlcNAcylation is often challenging due to the difficulty of detecting and quantifying the modification. Thus, robust methods to study O-GlcNAcylation are essential to elucidate its key roles in the regulation of individual proteins, complex cellular processes, and disease. In this chapter, we describe a set of chemoenzymatic labeling methods to (1) detect O-GlcNAcylation on proteins of interest, (2) monitor changes in both the total levels of O-GlcNAcylation and its stoichiometry on proteins of interest, and (3) enable mapping of O-GlcNAc to specific serine/threonine residues within proteins to facilitate functional studies. First, we outline a procedure for the expression and purification of a multiuse mutant galactosyltransferase enzyme (Y289L GalT). We then describe the use of Y289L GalT to modify O-GlcNAc residues with a functional handle, N-azidoacetylgalactosamine (GalNAz). Finally, we discuss several applications of the copper-catalyzed azide-alkyne cycloaddition "click" reaction to attach various alkyne-containing chemical probes to GalNAz and demonstrate how this functionalization of O-GlcNAc-modified proteins can be used to realize (1)-(3) above. Overall, these methods, which utilize commercially available reagents and standard protein analytical tools, will serve to advance our understanding of the diverse and important functions of O-GlcNAcylation. © 2018 Elsevier Inc. All rights reserved.

Enrichment of ammonia concentration from aqua-ammonia vapors by using 3A molecular sieve

International Nuclear Information System (INIS)

Chiou, J.S.; Lin, T.M.; She, K.Y.; Chen, W.M.

2009-01-01

In aqua-ammonia refrigeration systems, the ammonia is the refrigerant and the water is the absorbent, the vapor produced in the generator always contains a small fraction of water. The removed of this residual water is a crucial issue in order to guarantee a reliable and efficient operation of these systems. Currently, the thermal distillation methods (via a rectifier and/or an analyzer) are used to further separate the water from aqua-ammonia mixtures. In this study, a molecular sieve module is used for ammonia purification. A thermal system with a 3A molecular sieve module was set up, and the conditions of working fluid entering into the sieve module is similar to that entering into the rectifier tower of a typical aqua-ammonia absorption system. Results from ammonia enrichment tests indicate the concentration of ammonia can be raised from about 80% up to about 99% if siever installation was properly arranged.

75 FR 42292 - List of Approved Spent Fuel Storage Casks: NAC-MPC System, Revision 6

Science.gov (United States)

2010-07-21

... Fuel Storage Casks: NAC-MPC System, Revision 6 AGENCY: Nuclear Regulatory Commission. ACTION: Direct...-MPC storage system as noted in Appendix B of the Technical Specifications (TS): Incorporation of a... include the following changes to the configuration of the NAC-MPC storage system as noted in Appendix B of...

Chemical Changes in Nonthermal Plasma-Treated N-Acetylcysteine (NAC) Solution and Their Contribution to Bacterial Inactivation.

Science.gov (United States)

Ercan, Utku K; Smith, Josh; Ji, Hai-Feng; Brooks, Ari D; Joshi, Suresh G

2016-02-02

In continuation of our previous reports on the broad-spectrum antimicrobial activity of atmospheric non-thermal dielectric barrier discharge (DBD) plasma treated N-Acetylcysteine (NAC) solution against planktonic and biofilm forms of different multidrug resistant microorganisms, we present here the chemical changes that mediate inactivation of Escherichia coli. In this study, the mechanism and products of the chemical reactions in plasma-treated NAC solution are shown. UV-visible spectrometry, FT-IR, NMR, and colorimetric assays were utilized for chemical characterization of plasma treated NAC solution. The characterization results were correlated with the antimicrobial assays using determined chemical species in solution in order to confirm the major species that are responsible for antimicrobial inactivation. Our results have revealed that plasma treatment of NAC solution creates predominantly reactive nitrogen species versus reactive oxygen species, and the generated peroxynitrite is responsible for significant bacterial inactivation.

A Gibberellin-Mediated DELLA-NAC Signaling Cascade Regulates Cellulose Synthesis in Rice.

Science.gov (United States)

Huang, Debao; Wang, Shaogan; Zhang, Baocai; Shang-Guan, Keke; Shi, Yanyun; Zhang, Dongmei; Liu, Xiangling; Wu, Kun; Xu, Zuopeng; Fu, Xiangdong; Zhou, Yihua

2015-06-01

Cellulose, which can be converted into numerous industrial products, has important impacts on the global economy. It has long been known that cellulose synthesis in plants is tightly regulated by various phytohormones. However, the underlying mechanism of cellulose synthesis regulation remains elusive. Here, we show that in rice (Oryza sativa), gibberellin (GA) signals promote cellulose synthesis by relieving the interaction between SLENDER RICE1 (SLR1), a DELLA repressor of GA signaling, and NACs, the top-layer transcription factors for secondary wall formation. Mutations in GA-related genes and physiological treatments altered the transcription of CELLULOSE SYNTHASE genes (CESAs) and the cellulose level. Multiple experiments demonstrated that transcription factors NAC29/31 and MYB61 are CESA regulators in rice; NAC29/31 directly regulates MYB61, which in turn activates CESA expression. This hierarchical regulation pathway is blocked by SLR1-NAC29/31 interactions. Based on the results of anatomical analysis and GA content examination in developing rice internodes, this signaling cascade was found to be modulated by varied endogenous GA levels and to be required for internode development. Genetic and gene expression analyses were further performed in Arabidopsis thaliana GA-related mutants. Altogether, our findings reveal a conserved mechanism by which GA regulates secondary wall cellulose synthesis in land plants and provide a strategy for manipulating cellulose production and plant growth. © 2015 American Society of Plant Biologists. All rights reserved.

Innovative bioelectrochemical-anaerobic-digestion integrated system for ammonia recovery and bioenergy production from ammonia-rich residues

DEFF Research Database (Denmark)

Zhang, Yifeng; Angelidaki, Irini

2015-01-01

(SMRC) and a continuous stirred tank reactor (CSTR), to prevent ammonia toxicity during anaerobic digestion by in-situ ammonia recovery and electricity production (Figure 1). In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L with an average recovery rate of 0.18 g-N/L(CSTR...... performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative effect on the ammonia transportation. In continuous reactor operation, 112% extra biogas production was achieved due to ammonia recovery. High-throughput molecular sequencing analysis showed an impact...... of ammonia recovery on the microbial community composition in the integrated system. Results clearly indicate the great potential of the SMRC-CSTR-coupled system for efficient and cost-effective ammonia recovery, energy production and treatment of ammonia-rich residues....

Genome-wide identification and expression analysis of the CaNAC family members in chickpea during development, dehydration and ABA treatments.

Directory of Open Access Journals (Sweden)

Chien Van Ha

Full Text Available The plant-specific NAC transcription factors (TFs play important roles in regulation of diverse biological processes, including development, growth, cell division and responses to environmental stimuli. In this study, we identified the members of the NAC TF family of chickpea (Cicer arietinum and assess their expression profiles during plant development and under dehydration and abscisic acid (ABA treatments in a systematic manner. Seventy-one CaNAC genes were detected from the chickpea genome, including 8 membrane-bound members of which many might be involved in dehydration responses as judged from published literature. Phylogenetic analysis of the chickpea and well-known stress-related Arabidopsis and rice NACs enabled us to predict several putative stress-related CaNACs. By exploring available transcriptome data, we provided a comprehensive expression atlas of CaNACs in various tissues at different developmental stages. With the highest interest in dehydration responses, we examined the expression of the predicted stress-related and membrane-bound CaNACs in roots and leaves of chickpea seedlings, subjected to well-watered (control, dehydration and ABA treatments, using real-time quantitative PCR (RT-qPCR. Nine-teen of the 23 CaNACs examined were found to be dehydration-responsive in chickpea roots and/or leaves in either ABA-dependent or -independent pathway. Our results have provided a solid foundation for selection of promising tissue-specific and/or dehydration-responsive CaNAC candidates for detailed in planta functional analyses, leading to development of transgenic chickpea varieties with improved productivity under drought.

The role of peu-miR164 and its target PeNAC genes in response to abiotic stress in Populus euphratica.

Science.gov (United States)

Lu, Xin; Dun, Hui; Lian, Conglong; Zhang, Xiaofei; Yin, Weilun; Xia, Xinli

2017-06-01

Plant miR164 family is highly conserved and miR164 members regulate conserved targets belonging to NAC transcription factors. Our previous studies have revealed that peu-miR164a-e and its target gene POPTR_0007s08420 participate in abiotic stress response in Populus euphratica according to deep sequencing and degradome sequencing. In this study, miR164 family comprises six members that generate two mature products (miR164a-e and miR164f) and target seven NAC genes in P. euphratica. Co-expression in Nicotiana benthamiana and 5' RACE confirmed that peu-miR164 directs PeNAC070, PeNAC012 and PeNAC028 mRNAs cleavage. Expression profiles of primary peu-miR164 a/b/c/d/e bear similarity to those of peu-miR164a-e, whereas PeNAC070 and PeNAC081 showed inverse expression patterns with peu-miR164a-e under abiotic stresses. Existence of cis-acting elements in PeNAC070 promoter (ABRE,MBs, Box-W1, GC-motif, and W-box) and in peu-MIR164b promoter (HSE) further confirmed different responses of peu-miR164 and PeNAC070 to abiotic stresses. Histochemical β-glucuronidase (GUS) staining revealed that GUS activities increased when Pro PeNAC070 ::GUS transgenic Arabidopsis plants were exposed to NaCl, mannitol and abscisic acid (ABA), whereas GUS activity of Pro peu-MIR164b ::GUS plants decreased under ABA treatment. Subcellular localization and transactivation assays showed that PeNAC070 protein was localized to the nucleus and exhibited transactivation activity at the C-terminal. Overexpression of PeNAC070 in Arabidopsis promoted lateral root development, delayed stem elongation, and increased sensitivity of transgenic plants to drought and salt stresses. This study aids in understanding the adaptability of P. euphratica to extreme drought and salt environment by analysing tissue-specific expression patterns of miR164-regulated and specific promoter-regulated PeNAC genes. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Identification of GIG1, a GlcNAc-Induced Gene in Candida albicans Needed for Normal Sensitivity to the Chitin Synthase Inhibitor Nikkomycin Z▿§

Science.gov (United States)

Gunasekera, Angelo; Alvarez, Francisco J.; Douglas, Lois M.; Wang, Hong X.; Rosebrock, Adam P.; Konopka, James B.

2010-01-01

The amino sugar N-acetylglucosamine (GlcNAc) is known to be an important structural component of cells from bacteria to humans, but its roles in cell signaling are less well understood. GlcNAc induces two pathways in the human fungal pathogen Candida albicans. One activates cyclic AMP (cAMP) signaling, which stimulates the formation of hyphal cells and the expression of virulence genes, and the other pathway induces genes needed to catabolize GlcNAc. Microarray analysis of gene expression was carried out under four different conditions in order to characterize the transcriptional changes induced by GlcNAc. The most highly induced genes include those that encode a GlcNAc transporter (NGT1) and the GlcNAc catabolic enzymes (HXK1, DAC1, and NAG1). GlcNAc also activated most of the genes whose expression is increased when cells are triggered with other stimuli to form hyphae. Surprisingly, GlcNAc also induced a subset of genes that are regulated by galactose (GAL1, GAL7, and GAL10), which may be due to cross talk between signaling pathways. A novel GlcNAc-induced gene, GIG1, which is not essential for GlcNAc catabolism or the induction of hyphae, was identified. However, a Gig1-green fluorescent protein (GFP) fusion protein was specifically induced by GlcNAc, and not by other sugars. Gig1-GFP localized to the cytoplasm, where GlcNAc metabolism occurs. Significantly, a gig1Δ mutant displayed increased resistance to nikkomycin Z, which inhibits chitin synthase from converting UDP-GlcNAc into cell wall chitin. Gig1 is highly conserved in fungi, especially those that contain GlcNAc catabolic genes. These results implicate Gig1 in GlcNAc metabolism. PMID:20675577

RESULTS OF INITIAL AMMONIA OXIDATION TESTING

Energy Technology Data Exchange (ETDEWEB)

Nash, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fowley, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-12-30

This memo presents an experimental survey of aqueous phase chemical processes to remove aqueous ammonia from waste process streams. Ammonia is generated in both the current Hanford waste flowsheet and in future waste processing. Much ammonia will be generated in the Low Activity Waste (LAW) melters.i Testing with simulants in glass melters at Catholic University has demonstrated the significant ammonia production.ii The primary reaction there is the reducing action of sugar on nitrate in the melter cold cap. Ammonia has been found to be a problem in secondary waste stabilization. Ammonia vapors are noxious and destruction of ammonia could reduce hazards to waste treatment process personnel. It is easily evolved especially when ammonia-bearing solutions are adjusted to high pH.

Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

OpenAIRE

Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

2015-01-01

Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia.

Biosynthesis of the Common Polysaccharide Antigen of Pseudomonas aeruginosa PAO1: Characterization and Role of GDP-D-Rhamnose:GlcNAc/GalNAc-Diphosphate-Lipid α1,3-D-Rhamnosyltransferase WbpZ.

Science.gov (United States)

Wang, Shuo; Hao, Youai; Lam, Joseph S; Vlahakis, Jason Z; Szarek, Walter A; Vinnikova, Anna; Veselovsky, Vladimir V; Brockhausen, Inka

2015-06-15

The opportunistic pathogen Pseudomonas aeruginosa produces two major cell surface lipopolysaccharides, characterized by distinct O antigens, called common polysaccharide antigen (CPA) and O-specific antigen (OSA). CPA contains a polymer of D-rhamnose (D-Rha) in α1-2 and α1-3 linkages. Three putative glycosyltransferase genes, wbpX, wbpY, and wbpZ, are part of the CPA biosynthesis cluster. To characterize the enzymatic function of the wbpZ gene product, we chemically synthesized the donor substrate GDP-D-Rha and enzymatically synthesized GDP-D-[(3)H]Rha. Using nuclear magnetic resonance (NMR) spectroscopy, we showed that WbpZ transferred one D-Rha residue from GDP-D-Rha in α1-3 linkage to both GlcNAc- and GalNAc-diphosphate-lipid acceptor substrates. WbpZ is also capable of transferring D-mannose (D-Man) to these acceptors. Therefore, WbpZ has a relaxed specificity with respect to both acceptor and donor substrates. The diphosphate group of the acceptor, however, is required for activity. WbpZ does not require divalent metal ion for activity and exhibits an unusually high pH optimum of 9. WbpZ from PAO1 is therefore a GDP-D-Rha:GlcNAc/GalNAc-diphosphate-lipid α1,3-D-rhamnosyltransferase that has significant activity of GDP-D-Man:GlcNAc/GalNAc-diphosphate-lipid α1,3-D-mannosyltransferase. We used site-directed mutagenesis to replace the Asp residues of the two DXD motifs with Ala. Neither of the mutant constructs of wbpZ (D172A or D254A) could be used to rescue CPA biosynthesis in the ΔwbpZ knockout mutant in a complementation assay. This suggested that D172 and D254 are essential for WbpZ function. This work is the first detailed characterization study of a D-Rha-transferase and a critical step in the development of CPA synthesis inhibitors. This is the first characterization of a D-rhamnosyltransferase and shows that it is essential in Pseudomonas aeruginosa for the synthesis of the common polysaccharide antigen. Copyright © 2015, American Society for

O-GlcNAc in cancer: An Oncometabolism-fueled vicious cycle.

Science.gov (United States)

Hanover, John A; Chen, Weiping; Bond, Michelle R

2018-06-01

Cancer cells exhibit unregulated growth, altered metabolism, enhanced metastatic potential and altered cell surface glycans. Fueled by oncometabolism and elevated uptake of glucose and glutamine, the hexosamine biosynthetic pathway (HBP) sustains glycosylation in the endomembrane system. In addition, the elevated pools of UDP-GlcNAc drives the O-GlcNAc modification of key targets in the cytoplasm, nucleus and mitochondrion. These targets include transcription factors, kinases, key cytoplasmic enzymes of intermediary metabolism, and electron transport chain complexes. O-GlcNAcylation can thereby alter epigenetics, transcription, signaling, proteostasis, and bioenergetics, key 'hallmarks of cancer'. In this review, we summarize accumulating evidence that many cancer hallmarks are linked to dysregulation of O-GlcNAc cycling on cancer-relevant targets. We argue that onconutrient and oncometabolite-fueled elevation increases HBP flux and triggers O-GlcNAcylation of key regulatory enzymes in glycolysis, Kreb's cycle, pentose-phosphate pathway, and the HBP itself. The resulting rerouting of glucose metabolites leads to elevated O-GlcNAcylation of oncogenes and tumor suppressors further escalating elevation in HBP flux creating a 'vicious cycle'. Downstream, elevated O-GlcNAcylation alters DNA repair and cellular stress pathways which influence oncogenesis. The elevated steady-state levels of O-GlcNAcylated targets found in many cancers may also provide these cells with a selective advantage for sustained growth, enhanced metastatic potential, and immune evasion in the tumor microenvironment.

Characterization of ppGalNAc-T18, a member of the vertebrate-specific Y subfamily of UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferases.

Science.gov (United States)

Li, Xing; Wang, Jing; Li, Wei; Xu, Yingjiao; Shao, Dong; Xie, Yinyin; Xie, Wenxian; Kubota, Tomomi; Narimatsu, Hisashi; Zhang, Yan

2012-05-01

The first step of mucin-type O-glycosylation is catalyzed by members of the UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase (ppGalNAc-T; EC 2.4.1.41) family. Each member of this family has unique substrate specificity and expression profiles. In this report, we describe a new subfamily of ppGalNAc-Ts, designated the Y subfamily. The Y subfamily consists of four members, ppGalNAc-T8, -T9, -T17 and -T18, in which the conserved YDX(5)WGGENXE sequence in the Gal/GalNAc-T motif of ppGalNAc-Ts is mutated to LDX(5)YGGENXE. Phylogenetic analysis revealed that the Y subfamily members only exist in vertebrates. All four Y subfamily members lack in vitro GalNAc-transferase activity toward classical substrates possibly because of the UDP-GalNAc-binding pocket mutants. However, ppGalNAc-T18, the newly identified defining member, was localized in the endoplasmic reticulum rather than the Golgi apparatus in lung carcinoma cells. The knockdown of ppGalNAc-T18 altered cell morphology, proliferation potential and changed cell O-glycosylation. ppGalNAc-T18 can also modulate the in vitro GalNAc-transferase activity of ppGalNAc-T2 and -T10, suggesting that it may be a chaperone-like protein. These findings suggest that the new Y subfamily of ppGalNAc-Ts plays an important role in protein glycosylation; characterizing their functions will provide new insight into the role of ppGalNAc-Ts.

Exergy analysis of industrial ammonia synthesis

International Nuclear Information System (INIS)

Kirova-Yordanova, Zornitza

2004-01-01

Exergy consumption of ammonia production plants depends strongly on the ammonia synthesis loop design. Due to the thermodynamically limited low degree of conversion of hydrogen-nitrogen mixture to ammonia, industrial ammonia synthesis is implemented as recycle process (so-called 'ammonia synthesis loop'). Significant quantities of reactants are recycled back to reactor, after the removal of ammonia at low temperatures. Modern ammonia synthesis plants use well-developed heat- and cold recovery to improve the reaction heat utilisation and to reduce the refrigeration costs. In this work, the exergy method is applied to estimate the effect of the most important process parameters on the exergy efficiency of industrial ammonia synthesis. A specific approach, including suitable definitions of the system boundaries and process parameters, is proposed. Exergy efficiency indexes are discussed in order to make the results applicable to ammonia synthesis loops of various designs. The dependence of the exergy losses on properly selected independent process parameters is studied. Some results from detailed exergy analysis of the most commonly used ammonia synthesis loop design configurations at a wide range of selected parameters values are shown

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

OpenAIRE

Nakagawa, Tatsunori; Stahl, David A.

2013-01-01

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopu...

A Gibberellin-Mediated DELLA-NAC Signaling Cascade Regulates Cellulose Synthesis in Rice[OPEN

Science.gov (United States)

Huang, Debao; Wang, Shaogan; Zhang, Baocai; Shang-Guan, Keke; Shi, Yanyun; Zhang, Dongmei; Liu, Xiangling; Wu, Kun; Xu, Zuopeng; Fu, Xiangdong; Zhou, Yihua

2015-01-01

Cellulose, which can be converted into numerous industrial products, has important impacts on the global economy. It has long been known that cellulose synthesis in plants is tightly regulated by various phytohormones. However, the underlying mechanism of cellulose synthesis regulation remains elusive. Here, we show that in rice (Oryza sativa), gibberellin (GA) signals promote cellulose synthesis by relieving the interaction between SLENDER RICE1 (SLR1), a DELLA repressor of GA signaling, and NACs, the top-layer transcription factors for secondary wall formation. Mutations in GA-related genes and physiological treatments altered the transcription of CELLULOSE SYNTHASE genes (CESAs) and the cellulose level. Multiple experiments demonstrated that transcription factors NAC29/31 and MYB61 are CESA regulators in rice; NAC29/31 directly regulates MYB61, which in turn activates CESA expression. This hierarchical regulation pathway is blocked by SLR1-NAC29/31 interactions. Based on the results of anatomical analysis and GA content examination in developing rice internodes, this signaling cascade was found to be modulated by varied endogenous GA levels and to be required for internode development. Genetic and gene expression analyses were further performed in Arabidopsis thaliana GA-related mutants. Altogether, our findings reveal a conserved mechanism by which GA regulates secondary wall cellulose synthesis in land plants and provide a strategy for manipulating cellulose production and plant growth. PMID:26002868

Renal Ammonia Metabolism and Transport

Science.gov (United States)

Weiner, I. David; Verlander, Jill W.

2015-01-01

Renal ammonia metabolism and transport mediates a central role in acid-base homeostasis. In contrast to most renal solutes, the majority of renal ammonia excretion derives from intrarenal production, not from glomerular filtration. Renal ammoniagenesis predominantly results from glutamine metabolism, which produces 2 NH4+ and 2 HCO3− for each glutamine metabolized. The proximal tubule is the primary site for ammoniagenesis, but there is evidence for ammoniagenesis by most renal epithelial cells. Ammonia produced in the kidney is either excreted into the urine or returned to the systemic circulation through the renal veins. Ammonia excreted in the urine promotes acid excretion; ammonia returned to the systemic circulation is metabolized in the liver in a HCO3−-consuming process, resulting in no net benefit to acid-base homeostasis. Highly regulated ammonia transport by renal epithelial cells determines the proportion of ammonia excreted in the urine versus returned to the systemic circulation. The traditional paradigm of ammonia transport involving passive NH3 diffusion, protonation in the lumen and NH4+ trapping due to an inability to cross plasma membranes is being replaced by the recognition of limited plasma membrane NH3 permeability in combination with the presence of specific NH3-transporting and NH4+-transporting proteins in specific renal epithelial cells. Ammonia production and transport are regulated by a variety of factors, including extracellular pH and K+, and by several hormones, such as mineralocorticoids, glucocorticoids and angiotensin II. This coordinated process of regulated ammonia production and transport is critical for the effective maintenance of acid-base homeostasis. PMID:23720285

Use of zeolite for removing ammonia and ammonia-caused toxicity in marine toxicity identification evaluations.

Science.gov (United States)

Burgess, R M; Perron, M M; Cantwell, M G; Ho, K T; Serbst, J R; Pelletier, M C

2004-11-01

Ammonia occurs in marine waters including effluents, receiving waters, and sediment interstitial waters. At sufficiently high concentrations, ammonia can be toxic to aquatic species. Toxicity identification evaluation (TIE) methods provide researchers with tools for identifying aquatic toxicants. For identifying ammonia toxicity, there are several possible methods including pH alteration and volatilization, Ulva lactuca addition, microbial degradation, and zeolite addition. Zeolite addition has been used successfully in freshwater systems to decrease ammonia concentrations and toxicity for several decades. However, zeolite in marine systems has been used less because ions in the seawater interfere with zeolite's ability to adsorb ammonia. The objective of this study was to develop a zeolite method for removing ammonia from marine waters. To accomplish this objective, we performed a series of zeolite slurry and column chromatography studies to determine uptake rate and capacity and to evaluate the effects of salinity and pH on ammonia removal. We also assessed the interaction of zeolite with several toxic metals. Success of the methods was also evaluated by measuring toxicity to two marine species: the mysid Americamysis bahia and the amphipod Ampelisca abdita. Column chromatography proved to be effective at removing a wide range of ammonia concentrations under several experimental conditions. Conversely, the slurry method was inconsistent and variable in its overall performance in removing ammonia and cannot be recommended. The metals copper, lead, and zinc were removed by zeolite in both the slurry and column treatments. The zeolite column was successful in removing ammonia toxicity for both the mysid and the amphipod, whereas the slurry was less effective. This study demonstrated that zeolite column chromatography is a useful tool for conducting marine water TIEs to decrease ammonia concentrations and characterize toxicity.

Ammonia toxicity: from head to toe?

Science.gov (United States)

Dasarathy, Srinivasan; Mookerjee, Rajeshwar P; Rackayova, Veronika; Rangroo Thrane, Vinita; Vairappan, Balasubramaniyan; Ott, Peter; Rose, Christopher F

2017-04-01

Ammonia is diffused and transported across all plasma membranes. This entails that hyperammonemia leads to an increase in ammonia in all organs and tissues. It is known that the toxic ramifications of ammonia primarily touch the brain and cause neurological impairment. However, the deleterious effects of ammonia are not specific to the brain, as the direct effect of increased ammonia (change in pH, membrane potential, metabolism) can occur in any type of cell. Therefore, in the setting of chronic liver disease where multi-organ dysfunction is common, the role of ammonia, only as neurotoxin, is challenged. This review provides insights and evidence that increased ammonia can disturb many organ and cell types and hence lead to dysfunction.

The influences of N-acetyl cysteine (NAC) on the cytotoxicity and mechanical properties of Poly-methylmethacrylate (PMMA)-based dental resin.

Science.gov (United States)

Jiao, Yang; Ma, Sai; Li, Jing; Shan, Lequn; Yang, Yanwei; Li, Meng; Chen, Jihua

2015-01-01

Objectives. This study aimed to investigate the influences of N-acetyl cysteine (NAC) on cytotoxicity and mechanical properties of Poly-methylmethacrylate (PMMA) dental resins. Methods. Experimental PMMA resin was prepared by incorporating various concentrations of NAC (0, 0.15, 0.3, 0.6 and 0.9 wt.%). MTT assay was performed to investigate viability of human dental pulp cells after exposure to extract of PMMA resin with or without NAC. Cell adhesion on resin specimens was examined with scanning electron microscopy. Degree of conversion was studied with Fourier Transform Infrared Spectroscopy (FTIR). Flexural strength, microhardness and surface roughness was evaluated using a universal testing machine, microhardness tester and optical profilometer, respectively. Results. Incorporation of NAC into PMMA resin significantly reduced its cytotoxicity and enhanced cell adhesion on its surface. NAC induced negative influences on the mechanical and physical properties of PMMA resin in a dose-dependent manner. The degree of conversion for all experimental PMMA resins reached as high as 72% after 24 h of polymerization. All the tested properties were maintained when the concentration of incorporated NAC was 0.15 wt.%. Conclusion. The addition of 0.15 wt.% NAC remarkably improved biocompatibility of PMMA resin without exerting significant negative influence on its mechanical and physical properties.

Evaluation of Oxidative Stress in Combination Therapy with D-penicillamine and N-Acetylcysteine (NAC in Lead Poisoning in Opium Addicts

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Saeedeh Shojaeepour

2017-12-01

Full Text Available Background: N-acetylcysteine (NAC is a putative antioxidant and has gained attention as a promising agent for chelating heavy metals including lead. Considering the animal studies results, we hypothesized that adding NAC to the treatment regimen may improve the success of treatment with lead chelators. Methods: A total of 46 patients who were lead-poisoned opioid addicts were divided into two groups randomly and treated with d-penicillamine (DP, 1g/day in four equal divided doses and NAC+DP (1 g/day + 150 mg/kg/day. The efficacy of treatment was evaluated by hospitalization period. Meanwhile, the oxidative stress parameters including lipid peroxidation, protein carbonyl, total antioxidant capacity (TAC, glutathione concentration and super oxide dismutase (SOD activity were determined on admission and discharge and compared with healthy normal controls. Results: Hospitalization period was not different between the two groups. Treatment with DP and DP+NAC significantly decreased oxidative stress in patients. On the discharge day, the SOD activity and TAC were significantly higher in DP+NAC group in comparison with the DP group. Conclusion: Although NAC recovers antioxidant capacity, the advantages of NAC in improvement of DP efficacy in lead poisoning is questionable. Further studies with larger sample size and combination with other chelators are recommended.

Ammonia Leak Locator Study

Science.gov (United States)

Dodge, Franklin T.; Wuest, Martin P.; Deffenbaugh, Danny M.

1995-01-01

The thermal control system of International Space Station Alpha will use liquid ammonia as the heat exchange fluid. It is expected that small leaks (of the order perhaps of one pound of ammonia per day) may develop in the lines transporting the ammonia to the various facilities as well as in the heat exchange equipment. Such leaks must be detected and located before the supply of ammonia becomes critically low. For that reason, NASA-JSC has a program underway to evaluate instruments that can detect and locate ultra-small concentrations of ammonia in a high vacuum environment. To be useful, the instrument must be portable and small enough that an astronaut can easily handle it during extravehicular activity. An additional complication in the design of the instrument is that the environment immediately surrounding ISSA will contain small concentrations of many other gases from venting of onboard experiments as well as from other kinds of leaks. These other vapors include water, cabin air, CO2, CO, argon, N2, and ethylene glycol. Altogether, this local environment might have a pressure of the order of 10(exp -7) to 10(exp -6) torr. Southwest Research Institute (SwRI) was contracted by NASA-JSC to provide support to NASA-JSC and its prime contractors in evaluating ammonia-location instruments and to make a preliminary trade study of the advantages and limitations of potential instruments. The present effort builds upon an earlier SwRI study to evaluate ammonia leak detection instruments [Jolly and Deffenbaugh]. The objectives of the present effort include: (1) Estimate the characteristics of representative ammonia leaks; (2) Evaluate the baseline instrument in the light of the estimated ammonia leak characteristics; (3) Propose alternative instrument concepts; and (4) Conduct a trade study of the proposed alternative concepts and recommend promising instruments. The baseline leak-location instrument selected by NASA-JSC was an ion gauge.

Rectal administration of 13N-ammonia in the study of ammonia metabolism

International Nuclear Information System (INIS)

Koen, Hirofumi

1980-01-01

13 N-ammonia produced by the cyclotron was instilled intrarectally in patients with liver diseases for the study of the turnover of rectally absorbed 13 N-ammonia. A positron camera connected to an on-line computer system was used for imaging of the liver and heart; 13 N-activity over the head was also recorded. Sequential changes of 13 N-activity in blood was measured, and chromatographic analysis of 13 N-labeled substances in blood was carried out using a Dowex 50W x 8 column. In the control, 13 N-ammonia was absorbed quickly into blood visualizing the liver shortly after administration, and hepatic uptake of 13 N-ammonia reached a plateau in 10 -- 15 min, whereas in patients with cirrhosis, the lung and heart were visualized in 5 min when the liver image was still faint. 13 N-activity over the head was apparently higher in the cirrhotic group. It was suggested that a large proportion of absorbed 13 N-ammonia bypassed liver cells and reached peripheral tissues. The heart/liver ratio of 13 N and 13 N over the head were closely correlated with various indices of portal hypertension. The relative proportion of 13 N-metabolites in blood was lower at 5 min and 15 min after administration in cirrhosis, suggesting a reduced capacity of the liver to remove and metabolize ammonia. (author)

Ammonia Emissions from Agriculture in China

Science.gov (United States)

Chen, Y.; Zhang, L.; Zhao, Y.; Huang, B.

2016-12-01

Ammonia (NH3) is an important alkaline pollutant in the atmosphere and it has various environmental and climatic effects. We will present an improved bottom-up estimate of ammonia emissions from agriculture in China at 0.5°×0.5° horizontal resolution and monthly variability. Ammonia emissions from fertilizer use are derived using data of crop planting area, fertilizer application time and rate for 18 main crops. Ammonia emission factors from fertilizer use are estimated as a function of soil properties such as soil pH, cation exchange capacity (CEC), and agricultural activity information such as crop type, fertilizer type, and application mode. We further consider ambient temperature and wind speed to account for the meteorological influences on ammonia emission factors of fertilizer use. We also estimate the ammonia emission from livestock over China using the mass-flow methodology. The derived ammonia emissions in China for the year 2005 are 4.55 Tg NH3 from fertilizer use and 6.96 Tg from livestock. Henan and Jiangsu provinces are the two largest emitting areas for ammonia from fertilizer use (470 Gg NH3 and 365 Gg NH3). Henan (621 Gg NH3) and Shandong (533 Gg NH3) have the largest ammonia emissions from livestock. Both ammonia emissions from fertilizer use and livestock have distinct seasonal variations; peaking in June for fertilizer use (822 Gg NH3) and in July for livestock (1244 Gg NH3), and are both lowest in January (80 Gg and 241 Gg, respectively). Combining with other ammonia source (eg. human waste and transport) estimates from the REAS v2.1 emission inventory, we show that total ammonia emissions in China for the year 2005 are 14.0 Tg NH3 a-1. Comparisons with satellite measurements of ammonia columns will also be presented.

Defences against ammonia toxicity in tropical air-breathing fishes exposed to high concentrations of environmental ammonia: a review.

Science.gov (United States)

Ip, Y K; Chew, S F; Wilson, J M; Randall, D J

2004-10-01

In the tropics, air-breathing fishes can be exposed to environmental ammonia when stranded in puddles of water during the dry season, during a stay inside a burrow, or after agricultural fertilization. At low concentrations of environmental ammonia, NH(3) excretion is impeded, as in aerial exposure, leading to the accumulation of endogenous ammonia. At high concentrations of environmental ammonia, which results in a reversed NH(3) partial pressure gradient (DeltaP(NH3)), there is retention of endogenous ammonia and uptake of exogenous ammonia. In this review, several tropical air-breathing fishes (giant mudskipper, African catfish, oriental weatherloach, swamp eel, four-eyed sleeper, abehaze and slender African lungfish), which can tolerate high environmental ammonia exposure, are used as examples to demonstrate how eight different adaptations can be involved in defence against ammonia toxicity. Four of these adaptations deal with ammonia toxicity at branchial and/or epithelial surfaces: (1) active excretion of NH(4)(+); (2) lowering of environmental pH; (3) low NH(3) permeability of epithelial surfaces; and (4) volatilization of NH(3), while another four adaptations ameliorate ammonia toxicity at the cellular and subcellular levels: (5) high tolerance of ammonia at the cellular and subcellular levels; (6) reduction in ammonia production; (7) glutamine synthesis; and (8) urea synthesis. The responses of tropical air-breathing fishes to high environmental ammonia are determined apparently by behavioural adaptations and the nature of their natural environments.

Efek N-Asetil-L- Sistein (NAC terhadap Kadar Adma Plasma dan Ekspresi Protein Vcam-l pada Disfungsi Endotel Tikus Diabetes

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Irma Santi

2016-12-01

Full Text Available Abstract Endothelial dysfunction is an early state of symptoms in a cardiovascular disease. An elevated oxidative stress plays a key role in the pathogenesis of macrovascular diabetic complication. The present study was design to evaluate the effect of NAC on plasma ADMA level and the expression of VCAM-1 protein on endothelial dysfunction in diabetic rats. Thirty male Sprague–Dawley rats were divided into 5 groups i.e. normal rats, diabetic rats, treatment with NAC 30 mg/kgBW, NAC 56 mg/ kgBW and NAC 100 mg/kgBW. Diabetic rats model was induced by intraperitonial administration of alloxan monohydrate at dose of 150 mg/kgBW, diabetes occurred on 3nd day after alloxan injection and then started treatment of N-acetyl-L-cystein for 28 days. ADMA plasma level was analyzed with Elisa Reader and the expression of VCAM-1 protein was evaluated by immunohistochemistry. Conclusion of this research is that treatment with NAC 30 mg/kgBW, NAC 56 mg/kgBW and NAC 100 mg/kgBW for 28 days may prevent oxidative stress indicated by the decreasing of plasma ADMA level by 45.8%: 55.75% and 65.92%, respectively and the decreasing of the expression of VCAM-1 protein on endothelial dysfunction in diabetic rat by 24%: 31.75% and 58.92%, respectively. Key words : (NAC, Endothelial dysfunction, ADMA, VCAM-1AbstrakDisfungsi endotel merupakan tahap awal pada penyakit kardiovaskular. Peningkatan stres oksidatif berperan penting dalam patogenesis komplikasi makrovaskular pada penyakit diabetes. Penelitian ini bertujuan untuk mengevaluasi efek N-asetil sistein (NAC dalam menurunkan kadar ADMA plasma dan ekspresi protein VCAM-1 pada disfungsi endotel tikus diabetes. 30 tikus jantan strain sprague- Dawley dibagi menjadi 5 kelompok yaitu kelompok normal, kelompok diabetes, kelompok perlakuan NAC pada dosis 30, 56 dan 100 mg/kgBB. Model tikus diabetes diperoleh dengan diinduksi aloksan monohidrat 150 mg/kgBB secara intraperitonial, kondisi diabetes terjadi pada hari ke-3 setelah

First Comprehensive In Silico Analysis of the Functional and Structural Consequences of SNPs in Human GalNAc-T1 Gene

Directory of Open Access Journals (Sweden)

Hussein Sheikh Ali Mohamoud

2014-01-01

Full Text Available GalNAc-T1, a key candidate of GalNac-transferases genes family that is involved in mucin-type O-linked glycosylation pathway, is expressed in most biological tissues and cell types. Despite the reported association of GalNAc-T1 gene mutations with human disease susceptibility, the comprehensive computational analysis of coding, noncoding and regulatory SNPs, and their functional impacts on protein level, still remains unknown. Therefore, sequence- and structure-based computational tools were employed to screen the entire listed coding SNPs of GalNAc-T1 gene in order to identify and characterize them. Our concordant in silico analysis by SIFT, PolyPhen-2, PANTHER-cSNP, and SNPeffect tools, identified the potential nsSNPs (S143P, G258V, and Y414D variants from 18 nsSNPs of GalNAc-T1. Additionally, 2 regulatory SNPs (rs72964406 and #x26; rs34304568 were also identified in GalNAc-T1 by using FastSNP tool. Using multiple computational approaches, we have systematically classified the functional mutations in regulatory and coding regions that can modify expression and function of GalNAc-T1 enzyme. These genetic variants can further assist in better understanding the wide range of disease susceptibility associated with the mucin-based cell signalling and pathogenic binding, and may help to develop novel therapeutic elements for associated diseases.

OGT (O-GlcNAc Transferase) Selectively Modifies Multiple Residues Unique to Lamin A.

Science.gov (United States)

Simon, Dan N; Wriston, Amanda; Fan, Qiong; Shabanowitz, Jeffrey; Florwick, Alyssa; Dharmaraj, Tejas; Peterson, Sherket B; Gruenbaum, Yosef; Carlson, Cathrine R; Grønning-Wang, Line M; Hunt, Donald F; Wilson, Katherine L

2018-05-17

The LMNA gene encodes lamins A and C with key roles in nuclear structure, signaling, gene regulation, and genome integrity. Mutations in LMNA cause over 12 diseases ('laminopathies'). Lamins A and C are identical for their first 566 residues. However, they form separate filaments in vivo, with apparently distinct roles. We report that lamin A is β- O -linked N -acetylglucosamine- (O -GlcNAc)-modified in human hepatoma (Huh7) cells and in mouse liver. In vitro assays with purified O -GlcNAc transferase (OGT) enzyme showed robust O -GlcNAcylation of recombinant mature lamin A tails (residues 385⁻646), with no detectable modification of lamin B1, lamin C, or 'progerin' (Δ50) tails. Using mass spectrometry, we identified 11 O -GlcNAc sites in a 'sweet spot' unique to lamin A, with up to seven sugars per peptide. Most sites were unpredicted by current algorithms. Double-mutant (S612A/T643A) lamin A tails were still robustly O -GlcNAc-modified at seven sites. By contrast, O -GlcNAcylation was undetectable on tails bearing deletion Δ50, which causes Hutchinson⁻Gilford progeria syndrome, and greatly reduced by deletion Δ35. We conclude that residues deleted in progeria are required for substrate recognition and/or modification by OGT in vitro. Interestingly, deletion Δ35, which does not remove the majority of identified O -GlcNAc sites, does remove potential OGT-association motifs (lamin A residues 622⁻625 and 639⁻645) homologous to that in mouse Tet1. These biochemical results are significant because they identify a novel molecular pathway that may profoundly influence lamin A function. The hypothesis that lamin A is selectively regulated by OGT warrants future testing in vivo, along with two predictions: genetic variants may contribute to disease by perturbing OGT-dependent regulation, and nutrient or other stresses might cause OGT to misregulate wildtype lamin A.

Senescence-associated barley NAC (NAM, ATAF1,2, CUC) transcription factor interacts with radical-induced cell death 1 through a disordered regulatory domain

DEFF Research Database (Denmark)

Kjaersgaard, Trine; Jensen, Michael K; Christiansen, Michael W

2011-01-01

as a transcriptional activator suggesting that an involvement of HvNAC013 and HvNAC005 in senescence will be different. HvNAC013 interacted with barley radical-induced cell death 1 (RCD1) via the very C-terminal part of its TRD, outside of the region containing the LP motif. No significant secondary structure...... (NAM, ATAF1,2, CUC) TF family are up-regulated during senescence in barley (Hordeum vulgare). Both HvNAC005 and HvNAC013 bound the conserved NAC DNA target sequence. Computational and biophysical analyses showed that both proteins are intrinsically disordered in their large C-terminal domains, which...... was induced in the HvNAC013 TRD upon interaction with RCD1. RCD1 also interacted with regions dominated by intrinsic disorder in TFs of the MYB and basic helix-loop-helix families. We propose that RCD1 is a regulatory protein capable of interacting with many different TFs by exploiting their intrinsic...

Scanning the available Dictyostelium discoideum proteome for O-linked GlcNAc glycosylation sitesusing neural networks

DEFF Research Database (Denmark)

Gupta, Ramneek; Jung, Eva; Gooley, Andrew A

1999-01-01

Dictyostelium discoideum has been suggested as a eukaryotic model organism for glycobiology studies. Presently, the characteristics of acceptor sites for the N-acetylglucosaminyl-transferases in Dictyostelium discoideum, which link GlcNAc in an alpha linkage to hydroxyl residues, are largely...... unknown. This motivates the development of a species specific method for prediction of O-linked GlcNAc glycosylation sites in secreted and membrane proteins of D. discoideum. The method presented here employs a jury of artificial neural networks. These networks were trained to recognize the sequence...... context and protein surface accessibility in 39 experimentally determined O-alpha-GlcNAc sites found in D. discoideum glycoproteins expressed in vivo. Cross-validation of the data revealed a correlation in which 97% of the glycosylated and nonglycosylated sites were correctly identified. Based...

Synthesis of ammonia using sodium melt.

Science.gov (United States)

Kawamura, Fumio; Taniguchi, Takashi

2017-09-14

Research into inexpensive ammonia synthesis has increased recently because ammonia can be used as a hydrogen carrier or as a next generation fuel which does not emit CO 2 . Furthermore, improving the efficiency of ammonia synthesis is necessary, because current synthesis methods emit significant amounts of CO 2 . To achieve these goals, catalysts that can effectively reduce the synthesis temperature and pressure, relative to those required in the Haber-Bosch process, are required. Although several catalysts and novel ammonia synthesis methods have been developed previously, expensive materials or low conversion efficiency have prevented the displacement of the Haber-Bosch process. Herein, we present novel ammonia synthesis route using a Na-melt as a catalyst. Using this route, ammonia can be synthesized using a simple process in which H 2 -N 2 mixed gas passes through the Na-melt at 500-590 °C under atmospheric pressure. Nitrogen molecules dissociated by reaction with sodium then react with hydrogen, resulting in the formation of ammonia. Because of the high catalytic efficiency and low-cost of this molten-Na catalyst, it provides new opportunities for the inexpensive synthesis of ammonia and the utilization of ammonia as an energy carrier and next generation fuel.

Pivotal Role of O-GlcNAc Modification in Cold-Induced Thermogenesis by Brown Adipose Tissue Through Mitochondrial Biogenesis.

Science.gov (United States)

Ohashi, Natsuko; Morino, Katsutaro; Ida, Shogo; Sekine, Osamu; Lemecha, Mengistu; Kume, Shinji; Park, Shi-Young; Choi, Cheol Soo; Ugi, Satoshi; Maegawa, Hiroshi

2017-09-01

Adipose tissues considerably influence metabolic homeostasis, and both white (WAT) and brown (BAT) adipose tissue play significant roles in lipid and glucose metabolism. O -linked N -acetylglucosamine ( O -GlcNAc) modification is characterized by the addition of N -acetylglucosamine to various proteins by O -GlcNAc transferase (Ogt), subsequently modulating various cellular processes. However, little is known about the role of O -GlcNAc modification in adipose tissues. Here, we report the critical role of O -GlcNAc modification in cold-induced thermogenesis. Deletion of Ogt in WAT and BAT using adiponectin promoter-driven Cre recombinase resulted in severe cold intolerance with decreased uncoupling protein 1 (Ucp1) expression. Furthermore, Ogt deletion led to decreased mitochondrial protein expression in conjunction with decreased peroxisome proliferator-activated receptor γ coactivator 1-α protein expression. This phenotype was further confirmed by deletion of Ogt in BAT using Ucp1 promoter-driven Cre recombinase, suggesting that O -GlcNAc modification in BAT is responsible for cold-induced thermogenesis. Hypothermia was significant under fasting conditions. This effect was mitigated after normal diet consumption but not after consumption of a fatty acid-rich ketogenic diet lacking carbohydrates, suggesting impaired diet-induced thermogenesis, particularly by fat. In conclusion, O -GlcNAc modification is essential for cold-induced thermogenesis and mitochondrial biogenesis in BAT. Glucose flux into BAT may be a signal to maintain BAT physiological responses. © 2017 by the American Diabetes Association.

O-Linked β-N-acetylglucosamine (O-GlcNAc) modification: a new pathway to decode pathogenesis of diabetic retinopathy.

Science.gov (United States)

Gurel, Zafer; Sheibani, Nader

2018-01-31

The incidence of diabetes continues to rise among all ages and ethnic groups worldwide. Diabetic retinopathy (DR) is a complication of diabetes that affects the retinal neurovasculature causing serious vision problems, including blindness. Its pathogenesis and severity is directly linked to the chronic exposure to high glucose conditions. No treatments are currently available to stop the development and progression of DR. To develop new and effective therapeutic approaches, it is critical to better understand how hyperglycemia contributes to the pathogenesis of DR at the cellular and molecular levels. We propose alterations in O-GlcNAc modification of target proteins during diabetes contribute to the development and progression of DR. The O-GlcNAc modification is regulated through hexosamine biosynthetic pathway. We showed this pathway is differentially activated in various retinal vascular cells under high glucose conditions perhaps due to their selective metabolic activity. O-GlcNAc modification can alter protein stability, activity, interactions, and localization. By targeting the same amino acid residues (serine and threonine) as phosphorylation, O-GlcNAc modification can either compete or cooperate with phosphorylation. Here we will summarize the effects of hyperglycemia-induced O-GlcNAc modification on the retinal neurovasculature in a cell-specific manner, providing new insight into the role of O-GlcNAc modification in early loss of retinal pericytes and the pathogenesis of DR. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

21 CFR 862.1065 - Ammonia test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ammonia test system. 862.1065 Section 862.1065....1065 Ammonia test system. (a) Identification. An ammonia test system is a device intended to measure ammonia levels in blood, serum, and plasma, Ammonia measurements are used in the diagnosis and treatment...

Loss of NAC1 expression is associated with defective bony patterning in the murine vertebral axis.

Directory of Open Access Journals (Sweden)

Kai Lee Yap

Full Text Available NAC1 encoded by NACC1 is a member of the BTB/POZ family of proteins and participates in several pathobiological processes. However, its function during tissue development has not been elucidated. In this study, we compared homozygous null mutant Nacc1(-/- and wild type Nacc1(+/+ mice to determine the consequences of diminished NAC1 expression. The most remarkable change in Nacc1(-/- mice was a vertebral patterning defect in which most knockout animals exhibited a morphological transformation of the sixth lumbar vertebra (L6 into a sacral identity; thus, the total number of pre-sacral vertebrae was decreased by one (to 25 in Nacc1(-/- mice. Heterozygous Nacc1(+/- mice had an increased tendency to adopt an intermediate phenotype in which L6 underwent partial sacralization. Nacc1(-/- mice also exhibited non-closure of the dorsal aspects of thoracic vertebrae T10-T12. Chondrocytes from Nacc1(+/+ mice expressed abundant NAC1 while Nacc1(-/- chondrocytes had undetectable levels. Loss of NAC1 in Nacc1(-/- mice was associated with significantly reduced chondrocyte migratory potential as well as decreased expression of matrilin-3 and matrilin-4, two cartilage-associated extracellular matrix proteins with roles in the development and homeostasis of cartilage and bone. These data suggest that NAC1 participates in the motility and differentiation of developing chondrocytes and cartilaginous tissues, and its expression is necessary to maintain normal axial patterning of murine skeleton.

Aquatic Life Criteria - Ammonia

Science.gov (United States)

Documents related to EPA's final 2013 Aquatic Life Ambient Water Quality Criteria for Ammonia (Freshwater). These documents pertain to the safe levels of Ammonia in water that should protect to the majority of species.

Wastewater Treatment with Ammonia Recovery System

OpenAIRE

M. Örvös; T. Balázs; K. F. Both

2008-01-01

From environmental aspect purification of ammonia containing wastewater is expected. High efficiency ammonia desorption can be done from the water by air on proper temperature. After the desorption process, ammonia can be recovered and used in another technology. The calculation method described below give some methods to find either the minimum column height or ammonia rich solution of the effluent.

Fracture strength of three all-ceramic systems: Top-Ceram compared with IPS-Empress and In-Ceram.

Science.gov (United States)

Quran, Firas Al; Haj-Ali, Reem

2012-03-01

The purpose of this study was to investigate the fracture loads and mode of failure of all-ceramic crowns fabricated using Top-Ceram and compare it with all-ceramic crowns fabricated from well-established systems: IPS-Empress II, In-Ceram. Thirty all-ceramic crowns were fabricated; 10 IPS-Empress II, 10 In-Ceram alumina and 10 Top-Ceram. Instron testing machine was used to measure the loads required to introduce fracture of each crown. Mean fracture load for In-Ceram alumina [941.8 (± 221.66) N] was significantly (p > 0.05) higher than those of Top-Ceram and IPS-Empress II. There was no statistically significant difference between Top-Ceram and IPS-Empress II mean fracture loads; 696.20 (+222.20) and 534 (+110.84) N respectively. Core fracture pattern was highest seen in Top- Ceram specimens.

Mucin-type O-glycosylation is controlled by short- and long-range glycopeptide substrate recognition that varies among members of the polypeptide GalNAc transferase family

DEFF Research Database (Denmark)

Revoredo, Leslie; Wang, Shengjun; Bennett, Eric Paul

2016-01-01

A large family of UDP-GalNAc:polypeptide GalNAc transferases (ppGalNAc-Ts) initiates and defines sites of mucin-type Ser/Thr-O-GalNAc glycosylation. Family members have been classified into peptide- and glycopeptide-preferring subfamilies, although both families possess variable activities agains...

[ManNAc, a new therapeutic agent to reduce Angptl4-induced proteinuria in MCD].

Science.gov (United States)

Clément, Lionel; Macé, Camille

2016-01-01

Current therapies used in minimal change disease (MCD) were originally designed to cure other diseases. They are only partially efficient, and present inconvenient side effects. Therefore, understanding the molecular mechanisms implicated in the pathogenesis of proteinuria in MCD could lead to new therapeutic strategies. A new experimental transgenic rat model of human MCD was generated. These NPHS2-Angptl4 transgenic rats over-express two different forms of the glycoprotein Angptl4 from the podocyte. The majority of the protein shows a lack of sialylation that is implicated in the pathogenesis of proteinuria. Supplementation of ManNAc, a precursor of sialic acid, significantly reduces albuminuria in those rats by increasing sialylation of the hyposialylated form of Angptl4. After treatment of the first episode of MCD with glucocorticoids in patients, ManNAc could be used as a maintenance drug, especially to reduce the frequency and intensity of relapse. ManNAc is a promising therapeutic agent for patients with MCD. © 2016 médecine/sciences – Inserm.

Cylinder supplied ammonia scrubber testing in IDMS

International Nuclear Information System (INIS)

Lambert, D.P.

1994-01-01

This report summarizes the results of the off-line testing the Integrated DWPF Melter System (IDMS) ammonia scrubbers using ammonia supplied from cylinders. Three additional tests with ammonia are planned to verify the data collected during off-line testing. Operation of the ammonia scrubber during IDMS SRAT and SME processing will be completed during the next IDMS run. The Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) scrubbers were successful in removing ammonia from the vapor stream to achieve ammonia vapor concentrations far below the 10 ppM vapor exit design basis. In most of the tests, the ammonia concentration in the vapor exit was lower than the detection limit of the analyzers so results are generally reported as <0.05 parts per million (ppM). During SRAT scrubber testing, the ammonia concentration was no higher than 2 ppM and during SME testing the ammonia concentration was no higher than 0.05 m

Localization of three human polypeptide GalNAc-transferases in HeLa cells suggests initiation of O-linked glycosylation throughout the Golgi apparatus

DEFF Research Database (Denmark)

Röttger, S; White, J; Wandall, H H

1998-01-01

O-glycosylation of proteins is initiated by a family of UDP-N-acetylgalactosamine:polypeptide N-acetylgalactos-aminyltransferases (GalNAc-T). In this study, we have localized endogenous and epitope-tagged human GalNAc-T1, -T2 and -T3 to the Golgi apparatus in HeLa cells by subcellular fractionation......, immunofluorescence and immunoelectron microscopy. We show that all three GalNAc-transferases are concentrated about tenfold in Golgi stacks over Golgi associated tubular-vesicular membrane structures. Surprisingly, we find that GalNAc-T1, -T2 and -T3 are present throughout the Golgi stack suggesting that initiation...... of O-glycosylation may not be restricted to the cis Golgi, but occur at multiple sites within the Golgi apparatus. GalNAc-T1 distributes evenly across the Golgi stack whereas GalNAc-T2 and -T3 reside preferentially on the trans side and in the medial part of the Golgi stack, respectively. Moreover, we...

CADDIS Volume 2. Sources, Stressors and Responses: Ammonia

Science.gov (United States)

Introduction to the ammonia module, when to list ammonia as a candidate cause, ways to measure ammonia, simple and detailed conceptual diagrams for ammonia, literature reviews and references for the ammonia module.

Application and influence of preoperative intervention intra-arterial chemotherapy (NAC) of uterine artery for endometrial carcinoma

International Nuclear Information System (INIS)

Zhu Xueqiong; Yue Tianfu; Wang Dehua

2001-01-01

Objective: To analyse the effect of preoperative persistent infusion chemotherapy via uterine artery on endometrial carcinoma and followed by hysterectomy. Methods: According to the Seldinger's technique, polyethylene catheter was super selected into the uterine artery. The drugs were infused with cisplatin 100 mg and doxorubicin 50 mg in a consecutive low-dose method for five days. Radical surgery was performed about three or four weeks after NAC. The NAC group (n = 20) underwent surgery following intra-arterial chemotherapy, while the control group (n = 40) was randomly selected among the patients of endometrial carcinoma performed operations in the hospital. Results: One (5.0%) patient showed complete response in NAC group, the rates of complete response plus partial response were 60.0%. There were no significant differences in bleeding amounts, the operation time, the function recovery of bladder and bowel, the healing time of the incision between the two groups. Compared with the control group, infiltration larger than half of myometrium and lymph nodes involvement were statistically significant lower in NAC group (P < 0.05). Conclusions: Preparing intra-arterial chemotherapy may reduce tumor volume and possibly eradicate subclinical metastases without increasing the incidence of operative complications

Ammonia-based quantum computer

International Nuclear Information System (INIS)

Ferguson, Andrew J.; Cain, Paul A.; Williams, David A.; Briggs, G. Andrew D.

2002-01-01

We propose a scheme for quantum computation using two eigenstates of ammonia or similar molecules. Individual ammonia molecules are confined inside fullerenes and used as two-level qubit systems. Interaction between these ammonia qubits takes place via the electric dipole moments, and in particular we show how a controlled-NOT gate could be implemented. After computation the qubit is measured with a single-electron electrometer sensitive enough to differentiate between the dipole moments of different states. We also discuss a possible implementation based on a quantum cellular automaton

[Ceramic-on-ceramic bearings in total hip arthroplasty (THA)].

Science.gov (United States)

Sentürk, U; Perka, C

2015-04-01

The main reason for total hip arthroplasty (THA) revision is the wear-related aseptic loosening. Younger and active patients after total joint replacement create high demands, in particular, on the bearings. The progress, especially for alumina ceramic-on-ceramic bearings and mixed ceramics have solved many problems of the past and lead to good in vitro results. Modern ceramics (alumina or mixed ceramics containing alumina) are extremely hard, scratch-resistant, biocompatible, offer a low coefficient of friction, superior lubrication and have the lowest wear rates in comparison to all other bearings in THA. The disadvantage of ceramic is the risk of material failure, i.e., of ceramic fracture. The new generation of mixed ceramics (delta ceramic), has reduced the risk of head fractures to 0.03-0.05 %, but the risk for liner fractures remains unchanged at about 0.02 %. Assuming a non-impinging component implantation, ceramic-on-ceramic bearings have substantial advantages over all other bearings in THA. Due to the superior hardness, ceramic bearings produce less third body wear and are virtually impervious to damage from instruments during the implantation process. A specific complication for ceramic-on-ceramic bearings is "squeaking". The high rate of reported squeaking (0.45 to 10.7 %) highlights the importance of precise implant positioning and the stem and patient selection. With precise implant positioning this problem is rare with many implant designs and without clinical relevance. The improved tribology and the presumable resulting implant longevity make ceramic-on-ceramic the bearing of choice for young and active patients. Georg Thieme Verlag KG Stuttgart · New York.

Portfolio: Ceramics.

Science.gov (United States)

Hardy, Jane; And Others

1982-01-01

Describes eight art activities using ceramics. Elementary students created ceramic tiles to depict ancient Egyptian and medieval European art, made ceramic cookie stamps, traced bisque plates on sketch paper, constructed clay room-tableaus, and designed clay relief masks. Secondary students pit-fired ceramic pots and designed ceramic Victorian…

ENGINEERING DESIGN CONFIGURATIONS FOR BIOLOGICAL AMMONIA REMOVAL

Science.gov (United States)

Many regions in the United States have excessive levels of nutrients including ammonia in their source waters. For example, farming and agricultural sources of ammonia in the Midwest contribute to relatively high levels of ammonia in many ground waters. Although ammonia in water ...

Over-expression of a NAC 67 transcription factor from finger millet (Eleusine coracana L.) confers tolerance against salinity and drought stress in rice.

Science.gov (United States)

Rahman, Hifzur; Ramanathan, Valarmathi; Nallathambi, Jagedeeshselvam; Duraialagaraja, Sudhakar; Muthurajan, Raveendran

2016-05-11

NAC proteins (NAM (No apical meristem), ATAF (Arabidopsis transcription activation factor) and CUC (cup-shaped cotyledon)) are plant-specific transcription factors reported to be involved in regulating growth, development and stress responses. Salinity responsive transcriptome profiling in a set of contrasting finger millet genotypes through RNA-sequencing resulted in the identification of a NAC homolog (EcNAC 67) exhibiting differential salinity responsive expression pattern. Full length cDNA of EcNAC67 was isolated, characterized and validated for its role in abiotic stress tolerance through agrobacterium mediated genetic transformation in a rice cultivar ASD16. Bioinformatics analysis of putative NAC transcription factor (TF) isolated from a salinity tolerant finger millet showed its genetic relatedness to NAC67 family TFs in related cereals. Putative transgenic lines of rice over-expressing EcNAC67 were generated through Agrobacterium mediated transformation and presence/integration of transgene was confirmed through PCR and southern hybridization analysis. Transgenic rice plants harboring EcNAC67 showed enhanced tolerance against drought and salinity under greenhouse conditions. Transgenic rice plants were found to possess higher root and shoot biomass during stress and showed better revival ability upon relief from salinity stress. Upon drought stress, transgenic lines were found to maintain higher relative water content and lesser reduction in grain yield when compared to non-transgenic ASD16 plants. Drought induced spikelet sterility was found to be much lower in the transgenic lines than the non-transgenic ASD16. Results revealed the significant role of EcNAC67 in modulating responses against dehydration stress in rice. No detectable abnormalities in the phenotypic traits were observed in the transgenic plants under normal growth conditions. Results indicate that EcNAC67 can be used as a novel source for engineering tolerance against drought and salinity

Rectal administration of /sup 13/N-ammonia in the study of ammonia metabolism

Energy Technology Data Exchange (ETDEWEB)

Koen, H [Chiba Univ. (Japan). School of Medicine

1980-08-01

/sup 13/N-ammonia produced by the cyclotron was instilled intrarectally in patients with liver diseases for the study of the turnover of rectally absorbed /sup 13/N-ammonia. A positron camera connected to an on-line computer system was used for imaging of the liver and heart; /sup 13/N-activity over the head was also recorded. Sequential changes of /sup 13/N-activity in blood was measured, and chromatographic analysis of /sup 13/N-labeled substances in blood was carried out using a Dowex 50W x 8 column. In the control, /sup 13/N-ammonia was absorbed quickly into blood visualizing the liver shortly after administration, and hepatic uptake of /sup 13/N-ammonia reached a plateau in 10 -- 15 min, whereas in patients with cirrhosis, the lung and heart were visualized in 5 min when the liver image was still faint. /sup 13/N-activity over the head was apparently higher in the cirrhotic group. It was suggested that a large proportion of absorbed /sup 13/N-ammonia bypassed liver cells and reached peripheral tissues. The heart/liver ratio of /sup 13/N and /sup 13/N over the head were closely correlated with various indices of portal hypertension. The relative proportion of /sup 13/N-metabolites in blood was lower at 5 min and 15 min after administration in cirrhosis, suggesting a reduced capacity of the liver to remove and metabolize ammonia.

Ammonia Synthesis at Low Pressure.

Science.gov (United States)

Cussler, Edward; McCormick, Alon; Reese, Michael; Malmali, Mahdi

2017-08-23

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called "stranded," because it is only available far from population centers where it can be directly used. In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 °C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

Ammonia for hydrogen storage: challenges and opportunities

DEFF Research Database (Denmark)

Klerke, Asbjørn; Christensen, Claus H.; Nørskov, Jens Kehlet

2008-01-01

The possibility of using ammonia as a hydrogen carrier is discussed. Compared to other hydrogen storage materials, ammonia has the advantages of a high hydrogen density, a well-developed technology for synthesis and distribution, and easy catalytic decomposition. Compared to hydrocarbons...... and alcohols, it has the advantage that there is no CO2 emission at the end user. The drawbacks are mainly the toxicity of liquid ammonia and the problems related to trace amounts of ammonia in the hydrogen after decomposition. Storage of ammonia in metal ammine salts is discussed, and it is shown...... that this maintains the high volumetric hydrogen density while alleviating the problems of handling the ammonia. Some of the remaining challenges for research in ammonia as a hydrogen carrier are outlined....

Expression of binding properties of Gal/GalNAc reactive lectins by mammalian glycotopes (an updated report).

Science.gov (United States)

Wu, A M

2001-01-01

Expression of the binding properties of Gal/GalNAc specific lectins, based on the affinity of decreasing order of mammalian glycotopes (determinants) rather than monosaccharide inhibition pattern, is probably one of the best ways to express carbohydrate specifity and should facilitate the selection of lectins as structural probes for studying mammalian glycobiology. Eleven mammalian structural units have been selected to express the binding domain of applied lectins. They are: 1. F, GalNAcalpha1 --> 3GalNAc; 2. A, GalNAcalpha1 --> 3Gal; 3. T, Galbeta1 --> 3GalNAc; 4. I, Galbeta 1 --> 3GlcNAc; 5. II, Galbeta1 --> 4GlcNAc; 6. B, Galalpha1 --> 3Gal; 7. E, Galalpha1--> 4Gal; 8. L, Galbeta1 --> 4Glc; 9. P, GalNAcbeta1 --> 3Gal; 10. S, GalNAcbeta1 --> 4Gal and 11. Tn, GalNAcalpha1 --> 4Ser (Thr) of the peptide chain. Thus, the carbohydrate specificity of Gal/GalNAc reactive lectins can be divided into classes according to their highest affinity for the above disaccharides and/or Tn residue. Examples of the binding properties of these lectins can be demonstrated by Ricimus communis agglutinin (RCA1), grouped as II specific lectin and its binding property is II > I > B > T; Ahrus precatorius agglutinin (APA), classified as T and its carbohydrate specificity is T > I/II > E > B > Tn; Artocarpus integrifolia (jacalin, AIL), as T/Tn specific and its binding reactivity is T > Tn > I (II) and Geodia cydonium (GCL), as F/A specific, and with affinity for F > Ah [GalNAcalpha1-->43(L(Fuc)alpha1-->2)Gal] > I > L. Due to the multiple reactivity of lectins toward mammalian glycotopes, the possible existence of different combining sites or subsites in the same molecule has to be examined, and the differential binding properties of these combining sites (if any) have to be characterized. To establish the relationship among the amino acid sequences of the combining sites of plant lectins and mammalian glycotopes should be an important direction to be addressed in lectinology.

Tetraammineplatinum(II dichloride ammonia tetrasolvate

Directory of Open Access Journals (Sweden)

Tobias Grassl

2014-07-01

Full Text Available The title compound, [Pt(NH34]Cl2·4NH3, was crystallized in liquid ammonia from the salt PtCl2. The platinum cation is coordinated by four ammonia molecules, forming a square-planar complex. The chloride anions are surrounded by nine ammonia molecules, either bound within the platinum complex or solvent molecules. The solvent ammonia molecules are packed in such a way that an extended network of N—H...N and N—H...Cl hydrogen bonds is formed. The structure is isotypic with [Pd(NH34]Cl2·4NH3 [Grassl & Korber (2014. Acta Cryst. E70, i32].

Doppler spectroscopy of hydrogen Balmer lines in a hollow cathode glow discharge in ammonia and argon-ammonia mixture

International Nuclear Information System (INIS)

Sisovic, N. M.; Konjevic, N.

2008-01-01

The results of Doppler spectroscopy of hydrogen Balmer lines from a stainless steel (SS) and copper (Cu) hollow cathode (HC) glow discharge in ammonia and argon-ammonia mixture are reported. The experimental profiles in ammonia discharge are fitted well by superposing three Gaussian profiles. The half widths, in energy units, of narrow and medium Gaussians are in the ranges 0.3-0.4 eV and 3-4 eV, respectively, for both hollow cathodes what is expected on the basis of earlier electron beam→NH 3 experiments. The half widths of the largest Gaussian in ammonia are 46 and 55 eV for SS and Cu HC, respectively. In argon-ammonia discharge, three Gaussians are also required to fit experimental profiles. While half widths of narrow and medium Gaussians are similar to those in ammonia, the half widths of the largest Gaussians are 35 and 42 eV for SS and Cu HC, respectively. The half widths of the largest Gaussians in ammonia and in argon-ammonia mixture indicate the presence of excessive Doppler broadening.

A DNA-binding-site landscape and regulatory network analysis for NAC transcription factors in Arabidopsis thaliana

DEFF Research Database (Denmark)

Lindemose, Søren; Jensen, Michael Krogh; de Velde, Jan Van

2014-01-01

regulatory networks of 12 NAC transcription factors. Our data offer specific single-base resolution fingerprints for most TFs studied and indicate that NAC DNA-binding specificities might be predicted from their DNA-binding domain's sequence. The developed methodology, including the application......Target gene identification for transcription factors is a prerequisite for the systems wide understanding of organismal behaviour. NAM-ATAF1/2-CUC2 (NAC) transcription factors are amongst the largest transcription factor families in plants, yet limited data exist from unbiased approaches to resolve...... the DNA-binding preferences of individual members. Here, we present a TF-target gene identification workflow based on the integration of novel protein binding microarray data with gene expression and multi-species promoter sequence conservation to identify the DNA-binding specificities and the gene...

Natural variation in monoterpene synthesis in kiwifruit: transcriptional regulation of terpene synthases by NAC and ETHYLENE-INSENSITIVE3-like transcription factors.

Science.gov (United States)

Nieuwenhuizen, Niels J; Chen, Xiuyin; Wang, Mindy Y; Matich, Adam J; Perez, Ramon Lopez; Allan, Andrew C; Green, Sol A; Atkinson, Ross G

2015-04-01

Two kiwifruit (Actinidia) species with contrasting terpene profiles were compared to understand the regulation of fruit monoterpene production. High rates of terpinolene production in ripe Actinidia arguta fruit were correlated with increasing gene and protein expression of A. arguta terpene synthase1 (AaTPS1) and correlated with an increase in transcript levels of the 2-C-methyl-D-erythritol 4-phosphate pathway enzyme 1-deoxy-D-xylulose-5-phosphate synthase (DXS). Actinidia chinensis terpene synthase1 (AcTPS1) was identified as part of an array of eight tandemly duplicated genes, and AcTPS1 expression and terpene production were observed only at low levels in developing fruit. Transient overexpression of DXS in Nicotiana benthamiana leaves elevated monoterpene synthesis by AaTPS1 more than 100-fold, indicating that DXS is likely to be the key step in regulating 2-C-methyl-D-erythritol 4-phosphate substrate flux in kiwifruit. Comparative promoter analysis identified potential NAC (for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF], and cup-shaped cotyledon [CUC])-domain transcription factor) and ETHYLENE-INSENSITIVE3-like transcription factor (TF) binding sites in the AaTPS1 promoter, and cloned members of both TF classes were able to activate the AaTPS1 promoter in transient assays. Electrophoretic mobility shift assays showed that AaNAC2, AaNAC3, and AaNAC4 bind a 28-bp fragment of the proximal NAC binding site in the AaTPS1 promoter but not the A. chinensis AcTPS1 promoter, where the NAC binding site was mutated. Activation could be restored by reintroducing multiple repeats of the 12-bp NAC core-binding motif. The absence of NAC transcriptional activation in ripe A. chinensis fruit can account for the low accumulation of AcTPS1 transcript, protein, and monoterpene volatiles in this species. These results indicate the importance of NAC TFs in controlling monoterpene production and other traits in ripening fruits. © 2015 American

Ammonia as a Suitable Fuel for Fuel Cells

International Nuclear Information System (INIS)

Lan, Rong; Tao, Shanwen

2014-01-01

Ammonia, an important basic chemical, is produced at a scale of 150 million tons per year. Half of hydrogen produced in chemical industry is used for ammonia production. Ammonia containing 17.5 wt% hydrogen is an ideal carbon-free fuel for fuel cells. Compared to hydrogen, ammonia has many advantages. In this mini-review, the suitability of ammonia as fuel for fuel cells, the development of different types of fuel cells using ammonia as the fuel and the potential applications of ammonia fuel cells are briefly reviewed.

RhNAC2 and RhEXPA4 Are Involved in the Regulation of Dehydration Tolerance during the Expansion of Rose Petals1[C][W][OA

Science.gov (United States)

Dai, Fanwei; Zhang, Changqing; Jiang, Xinqiang; Kang, Mei; Yin, Xia; Lü, Peitao; Zhang, Xiao; Zheng, Yi; Gao, Junping

2012-01-01

Dehydration inhibits petal expansion resulting in abnormal flower opening and results in quality loss during the marketing of cut flowers. We constructed a suppression subtractive hybridization library from rose (Rosa hybrida) flowers containing 3,513 unique expressed sequence tags and analyzed their expression profiles during cycles of dehydration. We found that 54 genes were up-regulated by the first dehydration, restored or even down-regulated by rehydration, and once again up-regulated by the second dehydration. Among them, we identified a putative NAC family transcription factor (RhNAC2). With transactivation activity of its carboxyl-terminal domain in yeast (Saccharomyces cerevisiae) cell and Arabidopsis (Arabidopsis thaliana) protoplast, RhNAC2 belongs to the NAC transcription factor clade related to plant development in Arabidopsis. A putative expansin gene named RhEXPA4 was also dramatically up-regulated by dehydration. Silencing RhNAC2 or RhEXPA4 in rose petals by virus-induced gene silencing significantly decreased the recovery of intact petals and petal discs during rehydration. Overexpression of RhNAC2 or RhEXPA4 in Arabidopsis conferred strong drought tolerance in the transgenic plants. RhEXPA4 expression was repressed in RhNAC2-silenced rose petals, and the amino-terminal binding domain of RhNAC2 bound to the RhEXPA4 promoter. Twenty cell wall-related genes, including seven expansin family members, were up-regulated in Arabidopsis plants overexpressing RhNAC2. These data indicate that RhNAC2 and RhEXPA4 are involved in the regulation of dehydration tolerance during the expansion of rose petals and that RhEXPA4 expression may be regulated by RhNAC2. PMID:23093360

Tritiated ammonia formation

International Nuclear Information System (INIS)

Heung, L.K.

1995-01-01

When nitrogen was selected as the glovebox atmosphere for the Replacement Tritium Facility (RTF) at the Savannah River Site (SRS), a concern was raised as to the possibility of tritiated ammonia formation in the gloveboxes. Experimental data were produced to study the tritiated ammonia formation rate in a tritium and nitrogen mixture. A rate equation that closely simulates the experimental data was developed. This rate equation can be used to calculate the formation of tritiated ammonia from different concentrations of tritium and nitrogen. The reaction of T 2 and N 2 to form NT 3 is a slow process, particularly when the tritium concentration is low. The reaction requires weeks or months to reach radiochemical equilibrium dependent on the concentrations of the reactants. 4 refs., 6 figs., 1 tab

Surface modification of ceramics. Ceramics no hyomen kaishitsu

Energy Technology Data Exchange (ETDEWEB)

Hioki, T. (Toyota Central Research and Development Labs., Inc., Nagoya (Japan))

1993-07-05

Surface modification of ceramics and some study results using in implantation in surface modification are introduced. The mechanical properties (strength, fracture toughness, flaw resistance) of ceramics was improved and crack was repaired using surface modification by ion implantation. It is predicted that friction and wear properties are considerably affected because the hardness of ceramics is changed by ion implantation. Cementing and metalization are effective as methods for interface modification and the improvement of the adhesion power of the interface between metal and ceramic is their example. It was revealed that the improvement of mechanical properties of ceramics was achieved if appropriate surface modification was carried out. The market of ceramics mechanical parts is still small, therefore, the present situation is that the field of activities for surface modification of ceramics is also narrow. However, it is thought that in future, ceramics use may be promoted surely in the field like medicine and mechatronics. 8 refs., 4 figs.

(Bio)electrochemical ammonia recovery

NARCIS (Netherlands)

Kuntke, P.; Sleutels, T.H.J.A.; Rodríguez Arredondo, M.; Georg, S.; Barbosa, S.G.; Heijne, Ter A.; Hamelers, Hubertus V.M.; Buisman, C.J.N.

2018-01-01

In recent years, (bio)electrochemical systems (B)ES have emerged as an energy efficient alternative for the recovery of TAN (total ammonia nitrogen, including ammonia and ammonium) from wastewater. In these systems, TAN is removed or concentrated from the wastewater under the influence of an

Ammonia as a suitable fuel for fuel cells

Directory of Open Access Journals (Sweden)

Rong eLan

2014-08-01

Full Text Available Ammonia, an important basic chemical, is produced at a scale of 150 million tons per year. Half of hydrogen produced in chemical industry is used for ammonia production. Ammonia containing 17.5wt% hydrogen is an ideal carbon-free fuel for fuel cells. Compared to hydrogen, ammonia has many advantages. In this mini-review, the suitability of ammonia as fuel for fuel cells, the development of different types of fuel cells using ammonia as the fuel and the potential applications of ammonia fuel cells are briefly reviewed.

The performance of biological anaerobic filters packed with sludge-fly ash ceramic particles (SFCP) and commercial ceramic particles (CCP) during the restart period: effect of the C/N ratios and filter media.

Science.gov (United States)

Yue, Qinyan; Han, Shuxin; Yue, Min; Gao, Baoyu; Li, Qian; Yu, Hui; Zhao, Yaqin; Qi, Yuanfeng

2009-11-01

Two lab-scale upflow biological anaerobic filters (BAF) packed with sludge-fly ash ceramic particles (SFCP) and commercial ceramic particles (CCP) were employed to investigate effects of the C/N ratios and filter media on the BAF performance during the restart period. The results indicated that BAF could be restarted normally after one-month cease. The C/N ratio of 4.0 was the thresholds of nitrate removal and nitrite accumulation. TN removal and phosphate uptake reached the maximum value at the same C/N ratio of 5.5. Ammonia formation was also found and excreted a negative influence on TN removal, especially when higher C/N ratios were applied. Nutrients were mainly degraded within the height of 25 cm from the bottom. In addition, SFCP, as novel filter media manufactured by wastes-dewatered sludge and fly ash, represented a better potential in inhibiting nitrite accumulation, TN removal and phosphate uptake due to their special characteristics in comparison with CCP.

Ammonia tolerant enriched methanogenic cultures as bioaugmentation inocula to alleviate ammonia inhibition in continuous anaerobic reactors

DEFF Research Database (Denmark)

Fotidis, Ioannis; Wang, Han; Angelidaki, Irini

Ammonia is the most common inhibitor of anaerobic digestion (AD) process, resulting in suboptimal exploitation of the biogas potential of the feedstocks, causing significant economic losses to the biogas plants. Ammonia is mainly inhibiting the aceticlastic methanogens, while the hydrogenotrophic...... methanogens are more robust to ammonia toxicity effect. It has been shown that bioaugmentation of a pure strain of a hydrogenotrophic methanogen (i.e. Methanoculleus bourgensis) in an ammonia inhibited continuous anaerobic reactor can improve methane production more than 30%. Nevertheless, cultivation...... tolerant methanogenic culture as potential bioaugmentation inoculum in a continuous stirred tank reactor (CSTR) operating under “inhibited steady-state”, triggered by high ammonia levels (5 g NH4+-N L-1). The results of the current study established for the first time that bioaugmentation of an enriched...

Tetraamminepalladium(II dichloride ammonia tetrasolvate

Directory of Open Access Journals (Sweden)

Tobias Grassl

2014-07-01

Full Text Available The title compound, [Pd(NH34]Cl2·4NH3, was crystallized in liquid ammonia from the salt Pd(enCl2 (en is ethylenediamine and is isotypic with [Pt(NH34]Cl2·4NH3 [Grassl & Korber (2014. Acta Cryst. E70, i31]. The Pd2+ cation is coordinated by four ammonia molecules, exhibiting a square-planar geometry. The chloride anions are surrounded by nine ammonia molecules. These are either bound in the palladium complex or solvent molecules. The packing of the ammonia solvent molecules enables the formation of an extended network of N—H...N and N—H...Cl interactions with nearly ideal hydrogen-bonding geometry.

Dynamic study of ammonia metabolism after rectal administration of /sup 13/N-ammonia

Energy Technology Data Exchange (ETDEWEB)

Koen, H; Arimizu, N; Musha, H; Okuda, K; Tateno, Y [Chiba Univ. (Japan). School of Medicine

1980-01-01

/sup 13/N-ammonia produced by cyclotron, short lived positron emitter (Tl/2 10 min) was instilled intrarectally in a dose of 15 - 30 mCi with liver disease, in order to study the dynamic metabolism of rectally absorbed /sup 13/N-ammonia. A NIRS positron camera connected with an on-line computer system was used for imaging of the liver and heart. /sup 13/N-activity over the head was recorded by detectors used in renography. Sequential changes of /sup 13/N-activity in blood was measured, and chromatographic analysis of /sup 13/N-labeled substances in blood was performed using Dowex 50 W x 8. In the control, /sup 13/N-ammonia was absorbed quickly into blood visualizing the liver shortly after administration, and hepatic uptake of /sup 13/N-ammonia reached a plateau in 10 - 15 min, whereas in patients with cirrhosis, the lung and heart were visualized in 5 min when the liver image was still faint. /sup 13/N-activity over the head was apparently higher in the cirrhotic group compared with the control. It was suggested that a large proportion of injected /sup 13/N-ammonia bypassed liver cells and reached peripheral tissues. We determined the heart/liver activity ratio and this ratio at 15 min was found to be closely correlated with various indices of portal hypertension. The percentages of /sup 13/N-metabolite in blood at 5 min and 15 min were lower in the cirrhotic, suggesting reduced capacity of the liver to remove /sup 13/N-ammonia in cirrhosis.

Catalyst for Ammonia Oxidation

DEFF Research Database (Denmark)

2015-01-01

The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

Ammonia chemistry in a flameless jet

Energy Technology Data Exchange (ETDEWEB)

Zieba, Mariusz; Schuster, Anja; Scheffknecht, Guenter [Institute of Process Engineering and Power Plant Technology, University of Stuttgart, Pfaffenwaldring 23, D-70569 Stuttgart (Germany); Brink, Anders; Hupa, Mikko [Process Chemistry Centre, Aabo Akademi University, Biskopsgatan 8, 20500 Aabo (Finland)

2009-10-15

In this paper, the nitrogen chemistry in an ammonia (NH{sub 3}) doped flameless jet is investigated using a kinetic reactor network model. The reactor network model is used to explain the main differences in ammonia chemistry for methane (CH{sub 4})-containing fuels and methane-free fuels. The chemical pathways of nitrogen oxides (NO{sub x}) formation and destruction are identified using rate-of-production analysis. The results show that in the case of natural gas, ammonia reacts relatively late at fuel lean condition leading to high NO{sub x} emissions. In the pre-ignition zone, the ammonia chemistry is blocked due to the absence of free radicals which are consumed by methane-methyl radical (CH{sub 3}) conversion. In the case of methane-free gas, the ammonia reacted very rapidly and complete decomposition was reached in the fuel rich region of the jet. In this case the necessary radicals for the ammonia conversion are generated from hydrogen (H{sub 2}) oxidation. (author)

NMDA and dopamine D1 receptors within NAc-shell regulate IEG proteins expression in reward circuit during cocaine memory reconsolidation.

Science.gov (United States)

Li, Y; Ge, S; Li, N; Chen, L; Zhang, S; Wang, J; Wu, H; Wang, X; Wang, X

2016-02-19

Reactivation of consolidated memory initiates a memory reconsolidation process, during which the reactivated memory is susceptible to strengthening, weakening or updating. Therefore, effective interference with the memory reconsolidation process is expected to be an important treatment for drug addiction. The nucleus accumbens (NAc) has been well recognized as a pathway component that can prevent drug relapse, although the mechanism underlying this function is poorly understood. We aimed to clarify the regulatory role of the NAc in the cocaine memory reconsolidation process, by examining the effect of applying different pharmacological interventions to the NAc on Zif 268 and Fos B expression in the entire reward circuit after cocaine memory reactivation. Through the cocaine-induced conditioned place preference (CPP) model, immunohistochemical and immunofluorescence staining for Zif 268 and Fos B were used to explore the functional activated brain nuclei after cocaine memory reactivation. Our results showed that the expression of Zif 268 and Fos B was commonly increased in the medial prefrontal cortex (mPFC), the infralimbic cortex (IL), the NAc-core, the NAc-shell, the hippocampus (CA1, CA2, and CA3 subregions), the amygdala, the ventral tegmental area (VTA), and the supramammillary nucleus (SuM) following memory reconsolidation, and Zif 268/Fos B co-expression was commonly observed (for Zif 268: 51-68%; for Fos B: 52-66%). Further, bilateral NAc-shell infusion of MK 801 and SCH 23390, but not raclopride or propranolol, prior to addictive memory reconsolidation, decreased Zif 268 and Fos B expression in the entire reward circuit, except for the amygdala, and effectively disturbed subsequent CPP-related behavior. In summary, N-methyl-d-aspartate (NMDA) and dopamine D1 receptors, but not dopamine D2 or β adrenergic receptors, within the NAc-shell, may regulate Zif 268 and Fos B expression in most brain nuclei of the reward circuit after cocaine memory reactivation

Highly durable, coking and sulfur tolerant, fuel-flexible protonic ceramic fuel cells.

Science.gov (United States)

Duan, Chuancheng; Kee, Robert J; Zhu, Huayang; Karakaya, Canan; Chen, Yachao; Ricote, Sandrine; Jarry, Angelique; Crumlin, Ethan J; Hook, David; Braun, Robert; Sullivan, Neal P; O'Hayre, Ryan

2018-05-01

Protonic ceramic fuel cells, like their higher-temperature solid-oxide fuel cell counterparts, can directly use both hydrogen and hydrocarbon fuels to produce electricity at potentially more than 50 per cent efficiency 1,2 . Most previous direct-hydrocarbon fuel cell research has focused on solid-oxide fuel cells based on oxygen-ion-conducting electrolytes, but carbon deposition (coking) and sulfur poisoning typically occur when such fuel cells are directly operated on hydrocarbon- and/or sulfur-containing fuels, resulting in severe performance degradation over time 3-6 . Despite studies suggesting good performance and anti-coking resistance in hydrocarbon-fuelled protonic ceramic fuel cells 2,7,8 , there have been no systematic studies of long-term durability. Here we present results from long-term testing of protonic ceramic fuel cells using a total of 11 different fuels (hydrogen, methane, domestic natural gas (with and without hydrogen sulfide), propane, n-butane, i-butane, iso-octane, methanol, ethanol and ammonia) at temperatures between 500 and 600 degrees Celsius. Several cells have been tested for over 6,000 hours, and we demonstrate excellent performance and exceptional durability (less than 1.5 per cent degradation per 1,000 hours in most cases) across all fuels without any modifications in the cell composition or architecture. Large fluctuations in temperature are tolerated, and coking is not observed even after thousands of hours of continuous operation. Finally, sulfur, a notorious poison for both low-temperature and high-temperature fuel cells, does not seem to affect the performance of protonic ceramic fuel cells when supplied at levels consistent with commercial fuels. The fuel flexibility and long-term durability demonstrated by the protonic ceramic fuel cell devices highlight the promise of this technology and its potential for commercial application.

Ammonia excretion in Caenorhabditis elegans: mechanism and evidence of ammonia transport of the Rhesus protein CeRhr-1

Science.gov (United States)

Adlimoghaddam, Aida; Boeckstaens, Mélanie; Marini, Anna-Maria; Treberg, Jason R.; Brassinga, Ann-Karen C.; Weihrauch, Dirk

2015-01-01

ABSTRACT The soil-dwelling nematode Caenorhabditis elegans is a bacteriovorous animal, excreting the vast majority of its nitrogenous waste as ammonia (25.3±1.2 µmol gFW−1 day−1) and very little urea (0.21±0.004 µmol gFW−1 day−1). Although these roundworms have been used for decades as genetic model systems, very little is known about their strategy to eliminate the toxic waste product ammonia from their bodies into the environment. The current study provides evidence that ammonia is at least partially excreted via the hypodermis. Starvation reduced the ammonia excretion rates by more than half, whereas mRNA expression levels of the Rhesus protein CeRhr-2, V-type H+-ATPase (subunit A) and Na+/K+-ATPase (α-subunit) decreased correspondingly. Moreover, ammonia excretion rates were enhanced in media buffered to pH 5 and decreased at pH 9.5. Inhibitor experiments, combined with enzyme activity measurements and mRNA expression analyses, further suggested that the excretion mechanism involves the participation of the V-type H+-ATPase, carbonic anhydrase, Na+/K+-ATPase, and a functional microtubule network. These findings indicate that ammonia is excreted, not only by apical ammonia trapping, but also via vesicular transport and exocytosis. Exposure to 1 mmol l−1 NH4Cl caused a 10-fold increase in body ammonia and a tripling of ammonia excretion rates. Gene expression levels of CeRhr-1 and CeRhr-2, V-ATPase and Na+/K+-ATPase also increased significantly in response to 1 mmol l−1 NH4Cl. Importantly, a functional expression analysis showed, for the first time, ammonia transport capabilities for CeRhr-1 in a phylogenetically ancient invertebrate system, identifying these proteins as potential functional precursors to the vertebrate ammonia-transporting Rh-glycoproteins. PMID:25740900

46 CFR 154.1760 - Liquid ammonia.

Science.gov (United States)

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Liquid ammonia. 154.1760 Section 154.1760 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR....1760 Liquid ammonia. The master shall ensure that no person sprays liquid ammonia into a cargo tank...

Stabilities of protonated water-ammonia clusters

Science.gov (United States)

Sundén, A. E. K.; Støchkel, K.; Hvelplund, P.; Brøndsted Nielsen, S.; Dynefors, B.; Hansen, K.

2018-05-01

Branching ratios of water and ammonia evaporation have been measured for spontaneous evaporation from protonated mixed clusters H+(H2O)n(NH3)m in the size range 0 ≤ n ≤ 11 and 0 ≤ m ≤ 7. Mixed clusters evaporate water except for clusters containing six or more ammonia molecules, indicating the formation of a stable core of one ammonium ion surrounded by four ammonia molecules and a second shell consisting predominantly of water. We relate evaporative branching ratios to free energy differences between the products of competing channels and determine the free energy differences for clusters with up to seven ammonia molecules. Clusters containing up to five ammonia molecules show a very strong scaling of these free energy differences.

Genome-Wide Analyses of the NAC Transcription Factor Gene Family in Pepper (Capsicum annuum L.: Chromosome Location, Phylogeny, Structure, Expression Patterns, Cis-Elements in the Promoter, and Interaction Network

Directory of Open Access Journals (Sweden)

Weiping Diao

2018-03-01

Full Text Available The NAM, ATAF1/2, and CUC2 (NAC transcription factors form a large plant-specific gene family, which is involved in the regulation of tissue development in response to biotic and abiotic stress. To date, there have been no comprehensive studies investigating chromosomal location, gene structure, gene phylogeny, conserved motifs, or gene expression of NAC in pepper (Capsicum annuum L.. The recent release of the complete genome sequence of pepper allowed us to perform a genome-wide investigation of Capsicum annuum L. NAC (CaNAC proteins. In the present study, a comprehensive analysis of the CaNAC gene family in pepper was performed, and a total of 104 CaNAC genes were identified. Genome mapping analysis revealed that CaNAC genes were enriched on four chromosomes (chromosomes 1, 2, 3, and 6. In addition, phylogenetic analysis of the NAC domains from pepper, potato, Arabidopsis, and rice showed that CaNAC genes could be clustered into three groups (I, II, and III. Group III, which contained 24 CaNAC genes, was exclusive to the Solanaceae plant family. Gene structure and protein motif analyses showed that these genes were relatively conserved within each subgroup. The number of introns in CaNAC genes varied from 0 to 8, with 83 (78.9% of CaNAC genes containing two or less introns. Promoter analysis confirmed that CaNAC genes are involved in pepper growth, development, and biotic or abiotic stress responses. Further, the expression of 22 selected CaNAC genes in response to seven different biotic and abiotic stresses [salt, heat shock, drought, Phytophthora capsici, abscisic acid, salicylic acid (SA, and methyl jasmonate (MeJA] was evaluated by quantitative RT-PCR to determine their stress-related expression patterns. Several putative stress-responsive CaNAC genes, including CaNAC72 and CaNAC27, which are orthologs of the known stress-responsive Arabidopsis gene ANAC055 and potato gene StNAC30, respectively, were highly regulated by treatment with

Titan's Ammonia Feature

Science.gov (United States)

Smythe, W.; Nelson, R.; Boryta, M.; Choukroun, M.

2011-01-01

NH3 has long been considered an important component in the formation and evolution of the outer planet satellites. NH3 is particularly important for Titan, since it may serve as the reservoir for atmospheric nitrogen. A brightening seen on Titan starting in 2004 may arise from a transient low-lying fog or surface coating of ammonia. The spectral shape suggests the ammonia is anhydrous, a molecule that hydrates quickly in the presence of water.

27 CFR 21.96 - Ammonia, aqueous.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Ammonia, aqueous. 21.96 Section 21.96 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30 percent by...

Development of isoform-specific sensors of polypeptide GalNAc-transferase activity

DEFF Research Database (Denmark)

Song, Lina; Bachert, Collin; Schjoldager, Katrine T

2014-01-01

sequence influenced their activity and required modification, which we carried out based on previous in vitro work. Significantly, the modified T2 and T3 sensors were activated only in cells lacking their corresponding isozymes. Thus, we have developed T2- and T3-specific sensors that will be valuable......Humans express up to 20 isoforms of GalNAc-transferase (herein T1-T20) that localize to the Golgi apparatus and initiate O-glycosylation. Regulation of this enzyme family affects a vast array of proteins transiting the secretory pathway and diseases arise upon misregulation of specific isoforms....... Surprisingly, molecular probes to monitor GalNAc-transferase activity are lacking and there exist no effective global or isoform-specific inhibitors. Here we describe the development of T2- and T3-isoform specific fluorescence sensors that traffic in the secretory pathway. Each sensor yielded little signal...

Citrus CitNAC62 cooperates with CitWRKY1 to participate in citric acid degradation via up-regulation of CitAco3.

Science.gov (United States)

Li, Shao-Jia; Yin, Xue-Ren; Wang, Wen-Li; Liu, Xiao-Fen; Zhang, Bo; Chen, Kun-Song

2017-06-15

Citric acid is the predominant organic acid of citrus fruit. Degradation of citric acid occurs during fruit development, influencing fruit acidity. Associations of CitAco3 transcripts and citric acid degradation have been reported for citrus fruit. Here, transient overexpression of CitAco3 significantly reduced the citric acid content of citrus leaves and fruits. Using dual luciferase assays, it was shown that CitNAC62 and CitWRKY1 could transactivate the promoter of CitAco3. Subcellular localization results showed that CitWRKY1 was located in the nucleus and CitNAC62 was not. Yeast two-hybrid analysis and bimolecular fluorescence complementation (BiFC) assays indicated that the two differently located transcription factors could interact with each other. Furthermore, BiFC showed that the protein-protein interaction occurred only in the nucleus, indicating the potential mobility of CitNAC62 in plant cells. A synergistic effect on citrate content was observed between CitNAC62 and CitWRKY1. Transient overexpression of CitNAC62 or CitWRKY1 led to significantly lower citrate content in citrus fruit. The combined expression of CitNAC62 and CitWRKY1 resulted in lower citrate content compared with the expression of CitNAC62 or CitWRKY1 alone. The transcript abundance of CitAco3 was consistent with the citrate content. Thus, we propose that a complex of CitWRKY1 and CitNAC62 contributes to citric acid degradation in citrus fruit, potentially via modulation of CitAco3. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Members of the barley NAC transcription factor gene family show differential co-regulation with senescence-associated genes during senescence of flag leaves

DEFF Research Database (Denmark)

Christiansen, Michael W; Gregersen, Per L.

2014-01-01

-expressed with members of the NAC gene family. In conclusion, a list of up to 15 NAC genes from barley that are strong candidates for being regulatory factors of importance for senescence and biotic stress-related traits affecting the productivity of cereal crop plants has been generated. Furthermore, a list of 71...... in the NAC transcription factor family during senescence of barley flag leaves was studied. Several members of the NAC transcription factor gene family were up-regulated during senescence in a microarray experiment, together with a large range of senescence-associated genes, reflecting the coordinated...... activation of degradation processes in senescing barley leaf tissues. This picture was confirmed in a detailed quantitative reverse transcription–PCR (qRT–PCR) experiment, which also showed distinct gene expression patterns for different members of the NAC gene family, suggesting a group of ~15 out of the 47...

The effect of N-acetyl cysteine (NAC) on aluminum phosphide poisoning inducing cardiovascular toxicity: a case-control study.

Science.gov (United States)

Taghaddosinejad, Fakhreddin; Farzaneh, Esmaeil; Ghazanfari-Nasrabad, Mahdi; Eizadi-Mood, Nastaran; Hajihosseini, Morteza; Mehrpour, Omid

2016-01-01

Aluminum phosphide (AlP) is a very effective indoor and outdoor pesticide. We investigated the effects of N-acetyl cysteine (NAC) on the survival time, hemodynamics, and cardiac biochemical parameters at various time intervals in some cases of AlP poisoning. This research was a case-control study to evaluate 63 AlP poisoned patients during 2010-2012. Patients with cardiovascular complications of AlP to be treated with intravenous NAC plus conventional treatment were considered as the case group and compared with patients who did not receive NAC. NAC infusion was administered to the case group at 300 mg/kg for 20 h. The data gathered included age, sex, heart rate, Systolic blood pressure (SBP), creatine phosphokinase (CPK), creatine kinase MB (CK-MB), and ECG at the admission time and 12, 18, and 24 h after admission. Analysis of repeated measures was performed to check the variability of parameters over time. The mean ages in the case and control groups were 26.65 ± 1.06 (19-37 years) and 28.39 ± 1.11 (18-37 years), respectively (P = 0.266). Most of the patients were female (56.5%). CK-MB means were significantly different between the two groups, but no differences between the other variables were observed. Also, CK-MB, CPK, heart rate, and systolic blood pressure means became significantly different over time (0, 12, 18, and 24 h) in both groups (P managed by the positive role of NAC as the biochemical index of cardiotoxicity was found to elevate in both the case and control groups. Therefore, for the management protocol optimization, NAC evaluation should be done in further cases.

NAC transcription factor JUNGBRUNNEN1 enhances drought tolerance in tomato

KAUST Repository

Thirumalaikumar, Venkatesh P.

2017-06-22

Water deficit (drought stress) massively restricts plant growth and the yield of crops; reducing the deleterious effects of drought is therefore of high agricultural relevance. Drought triggers diverse cellular processes including the inhibition of photosynthesis, the accumulation of cell-damaging reactive oxygen species, and gene expression reprogramming, besides others. Transcription factors (TF) are central regulators of transcriptional reprogramming and expression of many TF genes is affected by drought, including members of the NAC family. Here, we identify the NAC factor JUNGBRUNNEN1 (JUB1) as a regulator of drought tolerance in tomato (Solanum lycopersicum). Expression of tomato JUB1 (SlJUB1) is enhanced by various abiotic stresses, including drought. Inhibiting SlJUB1 by virus-induced gene silencing drastically lowers drought tolerance concomitant with an increase in ion leakage, an elevation of hydrogen peroxide (H2 O2 ) levels, and a decrease of the expression of various drought-responsive genes. In contrast, overexpression of AtJUB1 from Arabidopsis thaliana increases drought tolerance in tomato, alongside with a higher relative leaf water content during drought and reduced H2 O2 levels. AtJUB1 was previously shown to stimulate expression of DREB2A, a TF involved in drought responses, and of the DELLA genes GAI and RGL1. We show here that SlJUB1 similarly controls the expression of the tomato orthologs SlDREB1, SlDREB2, and SlDELLA. Furthermore, AtJUB1 directly binds to the promoters of SlDREB1, SlDREB2 and SlDELLA in tomato. Our study highlights JUB1 as a transcriptional regulator of drought tolerance and suggests considerable conservation of the abiotic stress-related gene regulatory networks controlled by this NAC factor between Arabidopsis and tomato. This article is protected by copyright. All rights reserved.

Natural Variation in Monoterpene Synthesis in Kiwifruit: Transcriptional Regulation of Terpene Synthases by NAC and ETHYLENE-INSENSITIVE3-Like Transcription Factors1

Science.gov (United States)

Nieuwenhuizen, Niels J.; Chen, Xiuyin; Wang, Mindy Y.; Matich, Adam J.; Perez, Ramon Lopez; Allan, Andrew C.; Green, Sol A.; Atkinson, Ross G.

2015-01-01

Two kiwifruit (Actinidia) species with contrasting terpene profiles were compared to understand the regulation of fruit monoterpene production. High rates of terpinolene production in ripe Actinidia arguta fruit were correlated with increasing gene and protein expression of A. arguta terpene synthase1 (AaTPS1) and correlated with an increase in transcript levels of the 2-C-methyl-d-erythritol 4-phosphate pathway enzyme 1-deoxy-d-xylulose-5-phosphate synthase (DXS). Actinidia chinensis terpene synthase1 (AcTPS1) was identified as part of an array of eight tandemly duplicated genes, and AcTPS1 expression and terpene production were observed only at low levels in developing fruit. Transient overexpression of DXS in Nicotiana benthamiana leaves elevated monoterpene synthesis by AaTPS1 more than 100-fold, indicating that DXS is likely to be the key step in regulating 2-C-methyl-d-erythritol 4-phosphate substrate flux in kiwifruit. Comparative promoter analysis identified potential NAC (for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF], and cup-shaped cotyledon [CUC])-domain transcription factor) and ETHYLENE-INSENSITIVE3-like transcription factor (TF) binding sites in the AaTPS1 promoter, and cloned members of both TF classes were able to activate the AaTPS1 promoter in transient assays. Electrophoretic mobility shift assays showed that AaNAC2, AaNAC3, and AaNAC4 bind a 28-bp fragment of the proximal NAC binding site in the AaTPS1 promoter but not the A. chinensis AcTPS1 promoter, where the NAC binding site was mutated. Activation could be restored by reintroducing multiple repeats of the 12-bp NAC core-binding motif. The absence of NAC transcriptional activation in ripe A. chinensis fruit can account for the low accumulation of AcTPS1 transcript, protein, and monoterpene volatiles in this species. These results indicate the importance of NAC TFs in controlling monoterpene production and other traits in ripening fruits. PMID:25649633

Ammonia synthesis using magnetic induction method (MIM)

Science.gov (United States)

Puspitasari, P.; Razak, J. Abd; Yahya, N.

2012-09-01

The most challenging issues for ammonia synthesis is to get the high yield. New approach of ammonia synthesis by using Magnetic Induction Method (MIM) and the Helmholtz Coils has been proposed. The ammonia detection was done by using Kjeldahl Method and FTIR. The system was designed by using Autocad software. The magnetic field of MIM was vary from 100mT-200mT and the magnetic field for the Helmholtz coils was 14mT. The FTIR result shows that ammonia has been successfully formed at stretching peaks 1097,1119,1162,1236, 1377, and 1464 cm-1. UV-VIS result shows the ammonia bond at 195nm of wavelength. The ammonia yield was increase to 244.72μmole/g.h by using the MIM and six pairs of Helmholtz coils. Therefore this new method will be a new promising method to achieve the high yield ammonia at ambient condition (at 25δC and 1atm), under the Magnetic Induction Method (MIM).

Evaluation of ammonia metabolism in the skeletal muscles of patients with cirrhosis using N-13 ammonia PET

International Nuclear Information System (INIS)

Susumu Shiomi; Etsushi Kawamura; Takehiro Hayashi; Ai Oe; Jin Kotani; Hirotaka Ishizu; Kenji Torii; Joji Kawabe; Akihiro Tamori; Daiki Habu; Tadashi Takeda; Shuhei Nishiguchi

2004-01-01

Purpose: Hepatic encephalopathy is one of the causes of death of patients with liver cirrhosis, and treatment of this encephalopathy is important for patients with liver cirrhosis. Ammonia plays a major role in the pathogenesis of hepatic encephalopathy. Ammonia is mainly generated in vivo by deamination of amino acids in proteins ingested as food, but some is produced by intestinal bacteria. The generated ammonia reaches the liver through the portal vein, is converted to urea by means of the urea cycle and excreted from the kidney. In patients with decreased hepatic functional reserve or those with porto-systemic shunt, ammonia level in the blood rises. The excessive ammonia in such cases is mainly metabolized in skeletal muscles, However, skeletal muscles have no urea cycle, and therefore metabolize ammonia by producing glutamine from glutamate. Branched-chain amino acids (BCAA) is required for this reaction. Ammonia is considered the major pathogenetic factor of hepatic encephalopathy. It has been reported in animal experiments that skeletal muscles compensate for the decreased ammonia metabolism in cirrhotic liver. Positron emission tomography (PET) with N-13 ammonia has been widely used for the evaluation of myocardial perfusion. We examined ammonia metabolism in the skeletal muscles in patients with liver cirrhosis before and after administration of BCAA using N-13 ammonia PET.. Methods: The subjects were patients with cirrhosis underlying hepatitis C virus infection. Case 1 was a 68-year-old man diagnosed with compensated liver cirrhosis. Both ascites and encephalopathy were absent. The red blood cell count was 365 X 10 4 /ml, the platelet count was 14.6 serum albumin concentration was 4.2 g/dl, the cholinesterase activity was 396 IU/l, the total bi concentration was 0.6 mg/dl, the blood ammonia was 52 g/dl, the prothrombin time was 150%, and branched-chain amino acid and tyrosin ratio (BTR) was 6.60. Case 2 was a 69-year-old woman diagnosed with

Cyclic mechanical fatigue in ceramic-ceramic composites: an update

International Nuclear Information System (INIS)

Lewis, D. III

1983-01-01

Attention is given to cyclic mechanical fatigue effects in a number of ceramics and ceramic composites, including several monolithic ceramics in which significant residual stresses should be present as a result of thermal expansion mismatches and anisotropy. Fatigue is also noted in several BN-containing ceramic matrix-particulate composites and in SiC fiber-ceramic matrix composites. These results suggest that fatigue testing is imperative for ceramics and ceramic composites that are to be used in applications subject to cyclic loading. Fatigue process models are proposed which provide a rationale for fatigue effect observations, but do not as yet provide quantitative results. Fiber composite fatigue damage models indicate that design stresses in these materials may have to be maintained below the level at which fiber pullout occurs

Influence of Water Activated by Far infrared Porous Ceramics on Nitrogen Absorption in the Pig Feed.

Science.gov (United States)

Meng, Junping; Liu, Jie; Liang, Jinsheng; Zhang, Hongchen; Ding, Yan

2016-04-01

Under modern and, intensive feeding livestock and poultry density has increased, and brought a deterioration of the farm environment. The livestock and their excrement generate harmful gases such as ammonia, etc. which restricted the sustainable development and improvement of production efficiency of animal husbandry. In this paper, a new kind of far infrared porous ceramics was prepared to activate, the animal drinking water. The activated water and common water were then supplied to pigs, and the fresh pig feces of experimental group and:control group were collected on a regular basis. The residual protein content in feces was tested by Kjeldahl nitrogen method to study the influence law of the porous ceramics on absorbing nitrogen element in animal feces. The results showed that compared with the control group, the protein content in the experimental group decreased on average by 39.2%. The activated drinking water was conducive to the absorption of nitrogen in pig feed. The clusters of water molecules became smaller under the action of the porous ceramics. Hence, they were easy to pass through the water protein channel on the cell membrane for speeding up the metabolism.

Method for forming ammonia

Science.gov (United States)

Kong, Peter C.; Pink, Robert J.; Zuck, Larry D.

2008-08-19

A method for forming ammonia is disclosed and which includes the steps of forming a plasma; providing a source of metal particles, and supplying the metal particles to the plasma to form metal nitride particles; and providing a substance, and reacting the metal nitride particles with the substance to produce ammonia, and an oxide byproduct.

Sizing of an Ammonia Discharge Tank

Directory of Open Access Journals (Sweden)

Tuliagenda Beckfords

2011-01-01

Full Text Available Phosphate companies use well-stirred tanks to regulate the concentration of ammonia they discharge via their wastewater, preventing ammonia spikes from exceeding the cap set by the Environmental Protection Agency. This report discusses the methods used to determine the minimum possible volume of the tank required to regulate wastewater discharge. With this information, it was determined that the use of a stirring tank is an efficient and cost effective way to regulate ammonia discharge. Based on these results many other companies may use this method to decrease the negative effects of ammonia on the environment.

Modeling and simulation of ammonia removal from purge gases of ammonia plants using a catalytic Pd-Ag membrane reactor

International Nuclear Information System (INIS)

Rahimpour, M.R.; Asgari, A.

2008-01-01

In this work, the removal of ammonia from synthesis purge gas of an ammonia plant has been investigated. Since the ammonia decomposition is thermodynamically limited, a membrane reactor is used for complete decomposition. A double pipe catalytic membrane reactor is used to remove ammonia from purge gas. The purge gas is flowing in the reaction side and is converted to hydrogen and nitrogen over nickel-alumina catalyst. The hydrogen is transferred through the Pd-Ag membrane of tube side to the shell side. A mathematical model including conservation of mass in the tube and shell side of reactor is proposed. The proposed model was solved numerically and the effects of different parameters on the rector performance were investigated. The effects of pressure, temperature, flow rate (sweep ratio), membrane thickness and reactor diameter have been investigated in the present study. Increasing ammonia conversion was observed by raising the temperature, sweep ratio and reducing membrane thickness. When the pressure increases, the decomposition is gone toward completion but, at low pressure the ammonia conversion in the outset of reactor is higher than other pressures, but complete destruction of the ammonia cannot be achieved. The proposed model can be used for design of an industrial catalytic membrane reactor for removal of ammonia from ammonia plant and reducing NO x emissions

Manure application and ammonia volatilization

NARCIS (Netherlands)

Huijsmans, J.F.M.

2003-01-01

Keywords: manure application, ammonia volatilization, environmental conditions, application technique, incorporation technique, draught force, work organization, costs Livestock manure applied on farmland is an important source of ammonia (NH3) volatilization, and NH3 is a major atmospheric

Synthesis of ammonia with microwave plasma

International Nuclear Information System (INIS)

Xu Wenguo; Yu Aimin; Liu Jun; Jin Qinhan

1991-01-01

THe synthesis of ammonia absorbed on 13X zeolite with the aid of microwave plasma is described. The ammonia molecule absorbed on 13X zeolite as ammonium ions were detected by IR spectroscopy. The results obtained show that the ammonia synthesis is facilitated by the surface reactions of NH x (x = 1, 2) radicals adsorbed on zeolite with hydrogen atoms

Peripheral Ammonia as a Mediator of Methamphetamine Neurotoxicity

Science.gov (United States)

Halpin, Laura E.; Yamamoto, Bryan K.

2012-01-01

Ammonia is metabolized by the liver and has established neurological effects. The current study examined the possibility that ammonia contributes to the neurotoxic effects of methamphetamine (METH). The results show that a binge dosing regimen of METH to the rat increased plasma and brain ammonia concentrations that were paralleled by evidence of hepatotoxicity. The role of peripheral ammonia in the neurotoxic effects of METH was further substantiated by the demonstration that the enhancement of peripheral ammonia excretion blocked the increases in brain and plasma ammonia and attenuated the long term depletions of dopamine and serotonin typically produced by METH. Conversely, the localized perfusion of ammonia in combination with METH, but not METH alone or ammonia alone, into the striatum recapitulated the neuronal damage produced by the systemic administration of METH. Furthermore, this damage produced by the local administration of ammonia and METH was blocked by the GYKI 52466, an AMPA receptor antagonist. These findings highlight the importance of ammonia derived from the periphery as a small molecule mediator of METH neurotoxicity and more broadly emphasize the importance of peripheral organ damage as a possible mechanism that mediates the neuropathology produced by drugs of abuse and other neuroactive molecules. PMID:22993432

Ammonia gas permeability of meat packaging materials.

Science.gov (United States)

Karim, Faris; Hijaz, Faraj; Kastner, Curtis L; Smith, J Scott

2011-03-01

Meat products are packaged in polymer films designed to protect the product from exterior contaminants such as light, humidity, and harmful chemicals. Unfortunately, there is almost no data on ammonia permeability of packaging films. We investigated ammonia permeability of common meat packaging films: low-density polyethylene (LDPE; 2.2 mil), multilayer polyolefin (MLP; 3 mil), and vacuum (V-PA/PE; 3 mil, 0.6 mil polyamide/2.4 mil polyethylene). The films were fabricated into 10 × 5 cm pouches and filled with 50 mL deionized water. Pouches were placed in a plexiglass enclosure in a freezer and exposed to 50, 100, 250, or 500 ppm ammonia gas for 6, 12, 24, and 48 h at -17 ± 3 °C and 21 ± 3 °C. At freezing temperatures, no ammonia residues were detected and no differences in pH were found in the water. At room temperature, ammonia levels and pH of the water increased significantly (P packaging materials have low ammonia permeability and protect meat products exposed to ammonia leaks during frozen storage.

Method of forming a ceramic matrix composite and a ceramic matrix component

Science.gov (United States)

de Diego, Peter; Zhang, James

2017-05-30

A method of forming a ceramic matrix composite component includes providing a formed ceramic member having a cavity, filling at least a portion of the cavity with a ceramic foam. The ceramic foam is deposited on a barrier layer covering at least one internal passage of the cavity. The method includes processing the formed ceramic member and ceramic foam to obtain a ceramic matrix composite component. Also provided is a method of forming a ceramic matrix composite blade and a ceramic matrix composite component.

Cerebral ammonia metabolism in hyperammonemic rats

Energy Technology Data Exchange (ETDEWEB)

Cooper, A J; Mora, S N; Cruz, N F; Gelbard, A S

1985-06-01

The short-term metabolic fate of blood-borne (/sup 13/N)ammonia was determined in the brains of chronically (8- or 14-week portacaval-shunted rats) or acutely (urease-treated) hyperammonemic rats. Using a freeze-blowing technique it was shown that the overwhelming route for metabolism of blood-borne (/sup 13/N)ammonia in normal, chronically hyperammonemic and acutely hyperammonemic rat brain was incorporation into glutamine (amide). However, the rate of turnover of (/sup 13/N)ammonia to L-(amide-/sup 13/N)glutamine was slower in the hyperammonemic rat brain than in the normal rat brain. The activities of several enzymes involved in cerebral ammonia and glutamate metabolism were also measured in the brains of 14-week portacaval-shunted rats. The rat brain appears to have little capacity to adapt to chronic hyperammonemia because there were no differences in activity compared with those of weight-matched controls for the following brain enzymes involved in glutamate/ammonia metabolism: glutamine synthetase, glutamate dehydrogenase, aspartate aminotransferase, glutamine transaminase, glutaminase, and glutamate decarboxylase. The present findings are discussed in the context of the known deleterious effects on the CNS of high ammonia levels in a variety of diseases.

Cell cycle-dependent O-GlcNAc modification of tobacco histones and their interaction with the tobacco lectin.

Science.gov (United States)

Delporte, Annelies; De Zaeytijd, Jeroen; De Storme, Nico; Azmi, Abdelkrim; Geelen, Danny; Smagghe, Guy; Guisez, Yves; Van Damme, Els J M

2014-10-01

The Nicotiana tabacum agglutinin or Nictaba is a nucleocytoplasmic lectin that is expressed in tobacco after the plants have been exposed to jasmonate treatment or insect herbivory. Nictaba specifically recognizes GlcNAc residues. Recently, it was shown that Nictaba is interacting in vitro with the core histone proteins from calf thymus. Assuming that plant histones - similar to their animal counterparts - undergo O-GlcNAcylation, this interaction presumably occurs through binding of the lectin to the O-GlcNAc modification present on the histones. Hereupon, the question was raised whether this modification also occurs in plants and if it is cell cycle dependent. To this end, histones were purified from tobacco BY-2 suspension cells and the presence of O-GlcNAc modifications was checked. Concomitantly, O-GlcNAcylation of histone proteins was studied. Our data show that similar to animal histones plant histones are modified by O-GlcNAc in a cell cycle-dependent fashion. In addition, the interaction between Nictaba and tobacco histones was confirmed using lectin chromatography and far Western blot analysis. Collectively these findings suggest that Nictaba can act as a modulator of gene transcription through its interaction with core histones. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Ammonia stress under high environmental ammonia induces Hsp70 and Hsp90 in the mud eel, Monopterus cuchia.

Science.gov (United States)

Hangzo, Hnunlalliani; Banerjee, Bodhisattwa; Saha, Shrabani; Saha, Nirmalendu

2017-02-01

The obligatory air-breathing mud eel (Monopterus cuchia) is frequently being challenged with high environmental ammonia (HEA) exposure in its natural habitats. The present study investigated the possible induction of heat shock protein 70 and 90 (hsp70, hsc70, hsp90α and hsp90β) genes and more expression of Hsp70 and Hsp90 proteins under ammonia stress in different tissues of the mud eel after exposure to HEA (50 mM NH 4 Cl) for 14 days. HEA resulted in significant accumulation of toxic ammonia in different body tissues and plasma, which was accompanied with the stimulation of oxidative stress in the mud eel as evidenced by more accumulation of malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ) during exposure to HEA. Further, hyper-ammonia stress led to significant increase in the levels of mRNA transcripts for inducible hsp70 and hsp90α genes and also their translated proteins in different tissues probably as a consequence of induction of hsp70 and hsp90α genes in the mud eel. However, hyper-ammonia stress was neither associated with any significant alterations in the levels of mRNA transcripts for constitutive hsc70 and hsp90β genes nor their translated proteins in any of the tissues studied. More abundance of Hsp70 and Hsp90α proteins might be one of the strategies adopted by the mud eel to defend itself from the ammonia-induced cellular damages under ammonia stress. Further, this is the first report of ammonia-induced induction of hsp70 and hsp90α genes under hyper-ammonia stress in any freshwater air-breathing teleost.

Polymer-derived microporous ceramics for membranes and sensors for high temperature hydrogen purification and sensing

Energy Technology Data Exchange (ETDEWEB)

Prasad, Ravi Mohan

2012-06-11

activated and Knudsen diffusion. The stability and sensing characteristics of SnO{sub 2} sensors coated with amorphous microporous SiBCN layers have been studied in oxygen-free atmospheres. The SiBCN layers coated on SnO{sub 2} sensors are amorphous, crack-free and microporous. The diameter of micropores (about 0.70 nm) is larger than the kinetic diameter of H{sub 2} (0.289 nm) and CO (0.376 nm) molecules, allowing in this way their diffusion towards the bottom SnO{sub 2} sensing layer. Transient response characteristics and sensor signals of uncoated SnO{sub 2}, three-fold and five-fold SiBCN-coated SnO{sub 2} sensors exposed to CO (10, 20 and 120 ppm) and H{sub 2} (40, 400 and 900 ppm) in nitrogen at 350 and 530 C are obtained. Uncoated SnO{sub 2} sensor is reduced at 530 C in H{sub 2} to tin while SiBCN-coated SnO{sub 2} sensors show reversible resistance changes while exposed to CO and H{sub 2}. Si{sub 3}N{sub 4}-ceramics have been synthesized via a dry ammonia pyrolysis of commercially available polysilazane (KiON HTT 1800). Amorphous microporous-Si{sub 3}N{sub 4} ceramic layers deposited on the top of GaN sensing layer followed by dry ammonia treatment leads to the improved H{sub 2} to CO selectivity of Si{sub 3}N{sub 4}/GaN sensors in the oxygen-free atmosphere. Transient response of the uncoated-, three-fold Si{sub 3}N{sub 4} coated- and ammonia treated-GaN sensors exposed to CO (10, 20 and 120 ppm) and H{sub 2} (40, 400 and 900 ppm) in pure nitrogen at 350 and 530 C are investigated. The results indicate that uncoated-GaN sensor shows high response towards both CO and H{sub 2} whereas for microporous Si{sub 3}N{sub 4} coated- and ammonia treated-GaN gas sensors the sensitivity towards the interfering gas CO is significantly reduced. High-surface area micro- and mesoporous carbon-rich SiCN ceramics have been obtained by controlled thermolysis of a carbon-rich poly(diphenylsilylcarbodiimide) precursor under argon. The formation of porous SiCN ceramics is due to the

Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia.

Science.gov (United States)

Zhang, Yifeng; Angelidaki, Irini

2015-02-01

High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L during 30 days, resulting in an average recovery rate of 80 g-N/m(2)/d. Meanwhile, a maximum power density of 0.71±0.5 W/m(2) was generated at 2.85 A/m(2). Both current driven NH4(+) migration and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative effect on the ammonia transportation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation

Energy Technology Data Exchange (ETDEWEB)

Anheier, N.C. Jr.; McDonald, C.E.; Cuta, J.M.; Cuta, F.M.; Olsen, K.B.

1995-05-01

This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose of this work was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. PNL researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH{sub 4}{sup +}). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

New findings on cerebral ammonia uptake in HE using functional (13)N-ammonia PET

DEFF Research Database (Denmark)

Sørensen, Michael; Keiding, Susanne

2007-01-01

PET is a functional imaging technique suitable for studies of brain ammonia metabolism. Dynamic (13)N-ammonia PET yields time-courses of radioactivity concentrations in brain (PET camera) and blood (samples). Ahl et al. (Hepatology 40:73-79, 2004) and Keiding et al. (Hepatology 43:42-50, 2006...

Flexible ammonia handling strategies using both cutaneous and branchial epithelia in the highly ammonia-tolerant Pacific hagfish.

Science.gov (United States)

Clifford, Alexander M; Weinrauch, Alyssa M; Edwards, Susan L; Wilkie, Michael P; Goss, Greg G

2017-08-01

Hagfish consume carrion, potentially exposing them to hypoxia, hypercapnia, and high environmental ammonia (HEA). We investigated branchial and cutaneous ammonia handling strategies by which Pacific hagfish ( Eptatretus stoutii ) tolerate and recover from high ammonia loading. Hagfish were exposed to HEA (20 mmol/l) for 48 h to elevate plasma total ammonia (T Amm ) levels before placement into divided chambers for a 4-h recovery period in ammonia-free seawater where ammonia excretion ( J Amm ) was measured independently in the anterior and posterior compartments. Localized HEA exposures were also conducted by subjecting hagfish to HEA in either the anterior or posterior compartments. During recovery, HEA-exposed animals increased J Amm in both compartments, with the posterior compartment comprising ~20% of the total J Amm compared with ~11% in non-HEA-exposed fish. Plasma T Amm increased substantially when whole hagfish and the posterior regions were exposed to HEA. Alternatively, plasma T Amm did not elevate after anterior localized HEA exposure. J Amm was concentration dependent (0.05-5 mmol/l) across excised skin patches at up to eightfold greater rates than in skin sections that were excised from HEA-exposed hagfish. Skin excised from more posterior regions displayed greater J Amm than those from more anterior regions. Immunohistochemistry with hagfish-specific anti-rhesus glycoprotein type c (α-hRhcg; ammonia transporter) antibody was characterized by staining on the basal aspect of hagfish epidermis while Western blotting demonstrated greater expression of Rhcg in more posterior skin sections. We conclude that cutaneous Rhcg proteins are involved in cutaneous ammonia excretion by Pacific hagfish and that this mechanism could be particularly important during feeding. Copyright © 2017 the American Physiological Society.

A new classification system for all-ceramic and ceramic-like restorative materials.

Science.gov (United States)

Gracis, Stefano; Thompson, Van P; Ferencz, Jonathan L; Silva, Nelson R F A; Bonfante, Estevam A

2015-01-01

Classification systems for all-ceramic materials are useful for communication and educational purposes and warrant continuous revisions and updates to incorporate new materials. This article proposes a classification system for ceramic and ceramic-like restorative materials in an attempt to systematize and include a new class of materials. This new classification system categorizes ceramic restorative materials into three families: (1) glass-matrix ceramics, (2) polycrystalline ceramics, and (3) resin-matrix ceramics. Subfamilies are described in each group along with their composition, allowing for newly developed materials to be placed into the already existing main families. The criteria used to differentiate ceramic materials are based on the phase or phases present in their chemical composition. Thus, an all-ceramic material is classified according to whether a glass-matrix phase is present (glass-matrix ceramics) or absent (polycrystalline ceramics) or whether the material contains an organic matrix highly filled with ceramic particles (resin-matrix ceramics). Also presented are the manufacturers' clinical indications for the different materials and an overview of the different fabrication methods and whether they are used as framework materials or monolithic solutions. Current developments in ceramic materials not yet available to the dental market are discussed.

Chirality dependent interaction of ammonia with carbon nanotubes

Science.gov (United States)

Talukdar, Keka; Shantappa, Anil

2018-04-01

For the specific structure and extraordinary properties, carbon nanotubes (CNTs) have many applications in diversified fields. The interaction of CNTs with ammonia is a very interesting matter to study as it is related to the application of CNTs as ammonia sensor. Here the interaction of single walled zigzag, armchair and chiral carbon nanotubes is studied in respect of the change in energies before and after binding with ammonia by molecular dynamics simulation. Their deformation after simulation is modeled. The change of thermal conductivity of the CNTs is also found by simulation. The potential energy before and after absorption of ammonia gives useful information of the system. Thermal conductivities of the ammonia bound CNTs are changed considerably. It is observed that the potential energy and thermal conductivity both are changing for the interaction with ammonia and hence they are sensitive to ammonia binding.

Observations of atmospheric ammonia from TANSO-FTS/GOSAT

Science.gov (United States)

Someya, Yu; Imasu, Ryoichi; Saitoh, Naoko; Shiomi, Kei

2017-04-01

Atmospheric ammonia has large impacts on the nitrogen cycles or atmospheric environment such as nucleation of PM2.5 particles. It is reported that ammonia in the atmosphere has been increasing rapidly with the growth of population globally and this trend must continue in the future. Satellite observation is an effective approach to get to know the global perspectives of the gas. Atmospheric ammonia is observable using the thermal infrared (TIR) spectra, and IASI, TES and CrIS had been revealed those distributions. GOSAT also has TIR band including the ammonia absorption bands. GOSAT has the shorter revisit cycle than that of the other hyper-spectral TIR sounders mentioned above, therefore, the shorter time-scale events can be represented. In addition to the importance of the impacts of ammonia itself, the concentration ratio between ammonia and the other trace gases such as CO which is one of the main targets of the GOSAT-2 project is useful as the indicator of their emission sources. In this study, we introduce an algorithm to retrieve the column amount of atmospheric ammonia based on non-linear optimal estimation (Rogers, 2000) from GOSAT spectra in the ammonia absorption band between 960 - 970 cm-1. Temperature and water vapor profiles are estimated in advance of the ammonia retrieval. The preliminary results showed significant high concentrations of ammonia in the Northern India and the Eastern China as pointed out in the previous researches. We will discuss the global distribution of ammonia in the presentation.

Experimental study of mixed additive of Ni(II) and piperazine on ammonia escape in CO2 capture using ammonia solution

International Nuclear Information System (INIS)

Ma, Shuangchen; Chen, Gongda; Zhu, Sijie; Wen, Jiaqi; Gao, Ran; Ma, Lan; Chai, Jin

2016-01-01

Highlights: • Compound additive was used to obtain high CO 2 absorption efficiency and low NH 3 escape. • Both organic material and metal ion were applied as compound additive. • Influences of additives on CO 2 absorption and NH 3 escape were investigated. • Possible mechanism and products were analyzed by XRD and UV–visible spectrophotometer. - Abstract: In order to obtain high CO 2 absorption efficiency and low ammonia escape rate, mixed additives of piperazine and Ni(II) were used as absorbent in bubbling reactor. The effects of mixed additive on CO 2 absorption efficiency and ammonia escape rate were investigated; the performances of mixed additive in removal process were compared with that of pure ammonia solution. The proposed mechanism was analyzed by XRD and UV–visible spectrophotometer. The mixed additive has well effect on CO 2 absorption efficiency and ammonia escape reduction. The CO 2 absorption efficiency was 72% when 2 wt% ammonia solution mixed with 0.025 mol/L piperazine and 0.05 mol/L Ni(II), higher than that achieved by 3 wt% ammonia solution without additive, and the amount of ammonia loss was nearly 1/3 compared with 3 wt% pure ammonia solution. This paper provided one feasible method which is beneficial to the balance between CO 2 absorption and ammonia escape in CO 2 capture process.

Effect of dietary protein restriction on renal ammonia metabolism

Science.gov (United States)

Lee, Hyun-Wook; Osis, Gunars; Handlogten, Mary E.; Guo, Hui; Verlander, Jill W.

2015-01-01

Dietary protein restriction has multiple benefits in kidney disease. Because protein intake is a major determinant of endogenous acid production, it is important that net acid excretion change in parallel during protein restriction. Ammonia is the primary component of net acid excretion, and inappropriate ammonia excretion can lead to negative nitrogen balance. Accordingly, we examined ammonia excretion in response to protein restriction and then we determined the molecular mechanism of the changes observed. Wild-type C57Bl/6 mice fed a 20% protein diet and then changed to 6% protein developed an 85% reduction in ammonia excretion within 2 days, which persisted during a 10-day study. The expression of multiple proteins involved in renal ammonia metabolism was altered, including the ammonia-generating enzymes phosphate-dependent glutaminase (PDG) and phosphoenolpyruvate carboxykinase (PEPCK) and the ammonia-metabolizing enzyme glutamine synthetase. Rhbg, an ammonia transporter, increased in expression in the inner stripe of outer medullary collecting duct intercalated cell (OMCDis-IC). However, collecting duct-specific Rhbg deletion did not alter the response to protein restriction. Rhcg deletion did not alter ammonia excretion in response to dietary protein restriction. These results indicate 1) dietary protein restriction decreases renal ammonia excretion through coordinated regulation of multiple components of ammonia metabolism; 2) increased Rhbg expression in the OMCDis-IC may indicate a biological role in addition to ammonia transport; and 3) Rhcg expression is not necessary to decrease ammonia excretion during dietary protein restriction. PMID:25925252

A novel strategy for global mapping of O-GlcNAc proteins and peptides using selective enzymatic deglycosylation, HILIC enrichment and mass spectrometry identification.

Science.gov (United States)

Shen, Bingquan; Zhang, Wanjun; Shi, Zhaomei; Tian, Fang; Deng, Yulin; Sun, Changqing; Wang, Guangshun; Qin, Weijie; Qian, Xiaohong

2017-07-01

O-GlcNAcylation is a kind of dynamic O-linked glycosylation of nucleocytoplasmic and mitochondrial proteins. It serves as a major nutrient sensor to regulate numerous biological processes including transcriptional regulation, cell metabolism, cellular signaling, and protein degradation. Dysregulation of cellular O-GlcNAcylated levels contributes to the etiologies of many diseases such as diabetes, neurodegenerative disease and cancer. However, deeper insight into the biological mechanism of O-GlcNAcylation is hampered by its extremely low stoichiometry and the lack of efficient enrichment approaches for large-scale identification by mass spectrometry. Herein, we developed a novel strategy for the global identification of O-GlcNAc proteins and peptides using selective enzymatic deglycosylation, HILIC enrichment and mass spectrometry analysis. Standard O-GlcNAc peptides can be efficiently enriched even in the presence of 500-fold more abundant non-O-GlcNAc peptides and identified by mass spectrometry with a low nanogram detection sensitivity. This strategy successfully achieved the first large-scale enrichment and characterization of O-GlcNAc proteins and peptides in human urine. A total of 474 O-GlcNAc peptides corresponding to 457 O-GlcNAc proteins were identified by mass spectrometry analysis, which is at least three times more than that obtained by commonly used enrichment methods. A large number of unreported O-GlcNAc proteins related to cell cycle, biological regulation, metabolic and developmental process were found in our data. The above results demonstrated that this novel strategy is highly efficient in the global enrichment and identification of O-GlcNAc peptides. These data provide new insights into the biological function of O-GlcNAcylation in human urine, which is correlated with the physiological states and pathological changes of human body and therefore indicate the potential of this strategy for biomarker discovery from human urine. Copyright �

Wonderland of ceramics superplasticity; Ceramics chososei no sekai

Energy Technology Data Exchange (ETDEWEB)

Wakai, F. [National Industrial Research Inst. of Nagoya, Nagoya (Japan)

1995-07-01

It has been ten years since it was found that ceramics, which is strong and hard at room temperatures and does not deform at all, may exhibit a superplasticity phenomenon at high temperatures that it endlessly elongates when pulled as if it were chewing gum. This phenomenon is one of peculiar behaviours which nano-crystal ceramics, pulverized to an extent that the crystalline particle size is on the order of nanometers, show. The application of superplasticity made the material engineers`s old dream come true that hard ceramics are arbitrarily deformed and machined like metal. Using as models materials such as silicone nitride, alumina and zirconia, this paper describes the history and deformation mechanism of ceramics superplasticity, material design aiming at superplasticization and application of ceramics superplasticity to the machining technology. Furthermore, it describes the trend and future development of international joint researches on the basic surveys on ceramics superplasticity. 25 refs., 11 figs.

Synthetic Receptors for the High-Affinity Recognition of O-GlcNAc Derivatives

NARCIS (Netherlands)

Rios, Pablo; Carter, Tom S; Mooibroek, Tiddo J; Crump, Matthew P; Lisbjerg, Micke; Pittelkow, Michael; Supekar, Nitin T; Boons, Geert-Jan|info:eu-repo/dai/nl/088245489; Davis, Anthony P

2016-01-01

The combination of a pyrenyl tetraamine with an isophthaloyl spacer has led to two new water-soluble carbohydrate receptors ("synthetic lectins"). Both systems show outstanding affinities for derivatives of N-acetylglucosamine (GlcNAc) in aqueous solution. One receptor binds the methyl glycoside

Comparative study of ZnSe thin films deposited from modified chemical bath solutions with ammonia-containing and ammonia-free precursors

International Nuclear Information System (INIS)

Chen Liangyan; Zhang Daoli; Zhai Guangmei; Zhang Jianbing

2010-01-01

Ammonia is one of the complexing agents which are the most commonly used in the precursors of ZnSe thin films by chemical bath deposition, but its high volatility may be harmful to human beings and environments. In our experiments, ZnSe films were obtained from modified chemical solutions with ammonia-containing and ammonia-free precursors. X-ray diffraction, field-emission scanning electron microscope (FSEM), and absorption spectrum were applied to investigate the microstructure, morphology and optical properties of the samples obtained from both growth conditions, which were investigated in this work. The ammonia-free chemical bath deposited ZnSe films showed comparable properties with the ammonia-containing ones, indicating that ZnSe films from ammonia-free chemical solution may be preferred buffer layer in thin film solar cells with less environmental contamination.

Transport experience with the NAC-1 radioactive materials shipping cask

International Nuclear Information System (INIS)

Rollins, J.D.; Hoffman, C.C.

1976-01-01

During the first one and one-half years of operation of Nuclear Assurance Corporation's (NAC) four (4) second-generation NAC-1 truck casks, shipments of spent fuel assemblies, fuel rods, and other highly irradiated reactor components have involved over 300,000 cask miles of travel by land, and cask handling at some ten different nuclear facilities. This on-site experience has included the use of various types of auxiliary lifting devices, operational problems with which have identified the need to establish related Quality Assurance procedures in the area of post-fabrication testing. During the course of pre-shipment checkout and testing of the casks minor defects in the upper impact limiter and lower cask shielding wall have been detected and repaired according to procedure. One enroute occurrence with the cask in which an emergency response was implemented has emphasized the need for rigid adherence to procedural checkout before shipment. Periodic inspection and testing are performed as part of the cask license requirement whereby cask components are inspected and/or replaced. During such test periods leaking ball valves and a leaking neutron shield tank have been detected and repaired. (author)

Ceramic Laser Materials

Directory of Open Access Journals (Sweden)

Guillermo Villalobos

2012-02-01

Full Text Available Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements.

Ceramic Laser Materials

Science.gov (United States)

Sanghera, Jasbinder; Kim, Woohong; Villalobos, Guillermo; Shaw, Brandon; Baker, Colin; Frantz, Jesse; Sadowski, Bryan; Aggarwal, Ishwar

2012-01-01

Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG) ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements. PMID:28817044

Ammonia synthesis. Ammonia synthesis by N₂ and steam electrolysis in molten hydroxide suspensions of nanoscale Fe₂O₃.

Science.gov (United States)

Licht, Stuart; Cui, Baochen; Wang, Baohui; Li, Fang-Fang; Lau, Jason; Liu, Shuzhi

2014-08-08

The Haber-Bosch process to produce ammonia for fertilizer currently relies on carbon-intensive steam reforming of methane as a hydrogen source. We present an electrochemical pathway in which ammonia is produced by electrolysis of air and steam in a molten hydroxide suspension of nano-Fe2O3. At 200°C in an electrolyte with a molar ratio of 0.5 NaOH/0.5 KOH, ammonia is produced at 1.2 volts (V) under 2 milliamperes per centimeter squared (mA cm(-2)) of applied current at coulombic efficiency of 35% (35% of the applied current results in the six-electron conversion of N2 and water to ammonia, and excess H2 is cogenerated with the ammonia). At 250°C and 25 bar of steam pressure, the electrolysis voltage necessary for 2 mA cm(-2) current density decreased to 1.0 V. Copyright © 2014, American Association for the Advancement of Science.

Comparative Genomics of NAC Transcriptional Factors in Angiosperms: Implications for the Adaptation and Diversification of Flowering Plants

OpenAIRE

Pereira-Santana, Alejandro; Alcaraz, Luis David; Casta?o, Enrique; Sanchez-Calderon, Lenin; Sanchez-Teyer, Felipe; Rodriguez-Zapata, Luis

2015-01-01

NAC proteins constitute one of the largest groups of plant-specific transcription factors and are known to play essential roles in various developmental processes. They are also important in plant responses to stresses such as drought, soil salinity, cold, and heat, which adversely affect growth. The current knowledge regarding the distribution of NAC proteins in plant lineages comes from relatively small samplings from the available data. In the present study, we broadened the number of plan...

Liver X receptor regulates hepatic nuclear O-GlcNAc signaling and carbohydrate responsive element-binding protein activity

DEFF Research Database (Denmark)

Bindesbøll, Christian; Fan, Qiong; Nørgaard, Rikke C

2015-01-01

in response to feeding, which is believed to be mediated by insulin. We have previously shown that LXRs are targets for glucose-hexosamine-derived O-linked β-N-acetylglucosamine (O-GlcNAc) modification enhancing their ability to regulate SREBP-1c promoter activity in vitro. To elucidate insulin...... of glycolytic and lipogenic enzymes, including glucokinase (GK), SREBP-1c, ChREBPα, and the newly identified shorter isoform ChREBPβ. Furthermore, glucose-dependent increases in LXR/retinoid X receptor-regulated luciferase activity driven by the ChREBPα promoter was mediated, at least in part, by O-GlcNAc...... transferase (OGT) signaling in Huh7 cells. Moreover, we show that LXR and OGT interact and colocalize in the nucleus and that loss of LXRs profoundly reduced nuclear O-GlcNAc signaling and ChREBPα promoter binding activity in vivo. In summary, our study provides evidence that LXRs act as nutrient and glucose...

Synthesis of ammonia using sodium melt

OpenAIRE

Kawamura, Fumio; Taniguchi, Takashi

2017-01-01

Research into inexpensive ammonia synthesis has increased recently because ammonia can be used as a hydrogen carrier or as a next generation fuel which does not emit CO2. Furthermore, improving the efficiency of ammonia synthesis is necessary, because current synthesis methods emit significant amounts of CO2. To achieve these goals, catalysts that can effectively reduce the synthesis temperature and pressure, relative to those required in the Haber-Bosch process, are required. Although severa...

Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia

DEFF Research Database (Denmark)

Zhang, Yifeng; Angelidaki, Irini

2015-01-01

High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia...... recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7g-N/L during 30days, resulting in an average recovery rate of 80g-N/m2/d. Meanwhile, a maximum power density of 0.71±0.5W/m2 was generated at 2.85A/m2. Both current driven NH4+ migration...... and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative...

An antibody to the GM1/GalNAc-GD1a complex correlates with development of pure motor Guillain-Barré syndrome with reversible conduction failure.

Science.gov (United States)

Ogawa, Go; Kaida, Ken-ichi; Kuwahara, Motoi; Kimura, Fumihiko; Kamakura, Keiko; Kusunoki, Susumu

2013-01-15

Antibodies to a ganglioside complex consisting of GM1 and GalNAc-GD1a (GM1/GalNAc-GD1a) are found in sera from patients with Guillain-Barré syndrome (GBS). To elucidate the clinical significance of anti-GM1/GalNAc-GD1a antibodies in GBS, clinical features of 58 GBS patients with IgG anti-GM1/GalNAc-GD1a antibodies confirmed by enzyme-linked immunosorbent assay and thin layer chromatography immunostaining were analyzed. Compared to GBS patients without anti-GM1/GalNAc-GD1a antibodies, anti-GM1/GalNAc-GD1a-positive patients more frequently had a preceding respiratory infection (n=38, 66%, pbedridden cases were able to walk independently within one month after the nadir. These results show that the presence of anti-GM1/GalNAc-GD1a antibodies correlated with pure motor GBS characterized by antecedent respiratory infection, fewer cranial nerve deficits, and CBs at intermediate sites of motor nerves. The CB may be generated through alteration of the regulatory function of sodium channels in the nodal axolemma. Copyright © 2012 Elsevier B.V. All rights reserved.

USE OF ZEOLITE FOR REMOVING AMMONIA AND AMMONIA-CAUSED TOXCITY IN MARINE TOXICITY IDENTIFCATION EVALUATIONS (TIES)

Science.gov (United States)

Ammonia occurs in marine waters including effluents, receiving waters, and sediment interstitial waters. At sufficiently high concentrations, ammonia can be toxic to aquatic species. Toxicity identification evaluation (TIE) methods provide researchers with tools for identifyi...

Synthesis of disialyl Lewis a (Le(a)) structure in colon cancer cell lines by a sialyltransferase, ST6GalNAc VI, responsible for the synthesis of alpha-series gangliosides.

Science.gov (United States)

Tsuchida, Akiko; Okajima, Tetsuya; Furukawa, Keiko; Ando, Takayuki; Ishida, Hideharu; Yoshida, Aruto; Nakamura, Yoko; Kannagi, Reiji; Kiso, Makoto; Furukawa, Koichi

2003-06-20

Biosynthesis of disialyl Lewis a (Lea) was analyzed using previously cloned ST6GalNAc V and ST6GalNAc VI, which were responsible for the synthesis of alpha-series gangliosides. Among lactotetraosylceramide (Lc4), neolactotetraosylceramide, and their sialyl forms, only sialyl Lc4 was sialylated with ST6GalNAc V and ST6GalNAc VI. The products were confirmed to be disialyl Lea in TLC-immunostaining. Compared with the original substrate GM1b, the synthetic rates of disialyl Lea were 22 and 38% with ST6GalNAc V and ST6GalNAc VI, respectively. Since sialyl Lea could not be converted to disialyl Lea, disialyl Lea was produced only from disialyl Lc4. Therefore, it appears that ST6GalNAc V/VI and fucosyltransferase III (FUT-3) compete for sialyl Lc4, their common substrate. The results of either one transfection or co-transfection of two genes into COS1 cells revealed that both ST6GalNAc VI and FUT-3 contributed in the synthesis of disialyl Lea but partly compete with each other. Many colon cancer cell lines expressed the ST6GalNAc VI gene more or less, and some of them actually expressed disialyl Lea. None of them expressed ST6GalNAc V. These results suggested the novel substrate specificity of ST6GalNAc VI, which is responsible for the synthesis of disialyl Lea but not for alpha-series gangliosides in human colon tissues.

Resveratrol prevents ammonia toxicity in astroglial cells.

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Larissa Daniele Bobermin

Full Text Available Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS. Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS, GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA and extracellular signal-regulated kinase (ERK pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity.

Resveratrol Prevents Ammonia Toxicity in Astroglial Cells

Science.gov (United States)

Guerra, Maria Cristina; Leite, Marina Concli; Souza, Diogo Onofre; Gonçalves, Carlos-Alberto; Gottfried, Carmem

2012-01-01

Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO) production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS). Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS), GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA) and extracellular signal-regulated kinase (ERK) pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB) are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox) were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity. PMID:23284918

Ammonia production, excretion, toxicity, and defense in fish: A Review

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Alex Y K Ip

2010-10-01

Full Text Available Many fishes are ammonotelic but some species can detoxify ammonia to glutamine or urea. Certain fish species can accumulate high levels of ammonia in the brain or defense against ammonia toxicity by enhancing the effectiveness of ammonia excretion through active NH4+ transport, manipulation of ambient pH, or reduction in ammonia permeability through the branchial and cutaneous epithelia. Recent reports on ammonia toxicity in mammalian brain reveal the importance of permeation of ammonia through the blood-brain barrier and passages of ammonia and water through transporters in the plasmalemma of brain cells. Additionally, brain ammonia toxicity could be related to the passage of glutamine through the mitochondrial membranes into the mitochondrial matrix. On the other hand, recent reports on ammonia excretion in fish confirm the involvement of Rhesus glycoproteins in the branchial and cutaneous epithelia. Therefore, this review focuses on both the earlier literature and the up-to-date information on the problems and mechanisms concerning the permeation of ammonia, as NH3, NH4+ or proton-neutral nitrogenous compounds, across mitochondrial membranes, the blood-brain barrier, the plasmalemma of neurons, and the branchial and cutaneous epithelia of fish. It also addresses how certain fishes with high ammonia tolerance defend against ammonia toxicity through the regulation of the permeation of ammonia and related nitrogenous compounds through various types of membranes. It is hoped that this review would revive the interests in investigations on the passage of ammonia through the mitochondrial membranes and the blood-brain barrier of ammonotelic fishes and fishes with high brain ammonia-tolerance, respectively.

Ammonia transport in the kidney by Rhesus glycoproteins

Science.gov (United States)

Verlander, Jill W.

2014-01-01

Renal ammonia metabolism is a fundamental element of acid-base homeostasis, comprising a major component of both basal and physiologically altered renal net acid excretion. Over the past several years, a fundamental change in our understanding of the mechanisms of renal epithelial cell ammonia transport has occurred, replacing the previous model which was based upon diffusion equilibrium for NH3 and trapping of NH4+ with a new model in which specific and regulated transport of both NH3 and NH4+ across renal epithelial cell membranes via specific membrane proteins is required for normal ammonia metabolism. A major advance has been the recognition that members of a recently recognized transporter family, the Rhesus glycoprotein family, mediate critical roles in renal and extrarenal ammonia transport. The erythroid-specific Rhesus glycoprotein, Rh A Glycoprotein (Rhag), was the first Rhesus glycoprotein recognized as an ammonia-specific transporter. Subsequently, the nonerythroid Rh glycoproteins, Rh B Glycoprotein (Rhbg) and Rh C Glycoprotein (Rhcg), were cloned and identified as ammonia transporters. They are expressed in specific cell populations and membrane domains in distal renal epithelial cells, where they facilitate ammonia secretion. In this review, we discuss the distribution of Rhbg and Rhcg in the kidney, the regulation of their expression and activity in physiological disturbances, the effects of genetic deletion on renal ammonia metabolism, and the molecular mechanisms of Rh glycoprotein-mediated ammonia transport. PMID:24647713

NAC selectively inhibit cancer telomerase activity: A higher redox homeostasis threshold exists in cancer cells

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Pengying Li

2016-08-01

Full Text Available Telomerase activity controls telomere length, and this plays an important role in stem cells, aging and tumors. Antioxidant was shown to protect telomerase activity in normal cells but inhibit that in cancer cells, but the underlying mechanism is elusive. Here we found that 7721 hepatoma cells held a higher redox homeostasis threshold than L02 normal liver cells which caused 7721 cells to have a higher demand for ROS; MnSOD over-expression in 7721 decreased endogenous reactive oxygen species (ROS and inhibited telomerase activity; Akt phosphorylation inhibitor and NAC both inhibited 7721 telomerase activity. The over-elimination of ROS by NAC resulted in the inhibition of Akt pathway. Our results suggest that ROS is involved in the regulation of cancer telomerase activity through Akt pathway. The different intracellular redox homeostasis and antioxidant system in normal cells and tumor cells may be the cause of the opposite effect on telomerase activity in response to NAC treatment. Our results provide a theoretical base of using antioxidants selectively inhibit cancer telomerase activity. Findings of the present study may provide insights into novel approaches for cancer treatment.

Ammonia Test

Science.gov (United States)

... of Conditions Not Listed? Not Listed? Acidosis and Alkalosis Adrenal Insufficiency and Addison Disease Alcoholism Allergies Alzheimer ... ammonia, but both can damage the eyes, skin, respiratory tract, and, if swallowed, the mouth, throat, and ...

Upwind impacts of ammonia from an intensive poultry unit

International Nuclear Information System (INIS)

Jones, L.; Nizam, M.S.; Reynolds, B.; Bareham, S.; Oxley, E.R.B.

2013-01-01

This study investigated potential ammonia impacts on a sand dune nature reserve 600 m upwind of an intensive poultry unit. Ammonia concentrations and total nitrogen deposition were measured over a calendar year. A series of ammonia and nitrogen exposure experiments using dune grassland species were conducted in controlled manipulations and in the field. Ammonia emissions from the intensive poultry unit were detected up to 2.8 km upwind, contributing to exceedance of critical levels of ammonia 800 m upwind and exceedance of critical loads of nitrogen 2.8 km upwind. Emissions contributed 30% of the total N load in parts of the upwind conservation site. In the nitrogen exposure experiments, plants showed elevated tissue nitrogen contents, and responded to ammonia concentrations and nitrogen deposition loads observed in the conservation site by increasing biomass. Estimated long-term impacts suggest an increase in the soil carbon pool of 9% over a 50-year timescale. -- Highlights: •Ammonia from a poultry unit can be detected 2.8 km upwind. •Ammonia caused exceedance of critical levels 800 m and critical loads 2.8 km upwind. •Dune grassland species utilised ammonia as a nutrient source. •Plant biomass increased at low levels of ammonia and total nitrogen deposition. •Soil C pools are predicted to increase by 9% over 50 years due to the excess ammonia. -- Ammonia from a poultry unit has upwind impacts, exceeding critical levels 800 m and critical loads 2.8 km upwind, and increasing biomass and tissue N of dune grassland species

Synthetic assembly of novel avidin-biotin-GlcNAc (ABG) complex as an attractive bio-probe and its interaction with wheat germ agglutinin (WGA).

Science.gov (United States)

Kumari, Amrita; Koyama, Tetsuo; Hatano, Ken; Matsuoka, Koji

2016-10-01

A tetravalent GlcNAc pendant glycocluster was constructed with terminal biotin through C6 linker. To acquire the multivalent carbohydrate-protein interactions, we synthesized a glycopolymer of tetrameric structure using N-acetyl-d-glucosamine (GlcNAc) as the target carbohydrate by the use of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) as coupling reagent, followed by biotin-avidin complexation leading to the formation of glycocluster of avidin-biotin-GlcNAc conjugate (ABG complex). The dynamic light scattering (DLS) system was implied for size detection and to check the binding affinity of GlcNAc conjugate with a WGA lectin we use fluorometric assay by means of specific excitation of tryptophan at λex 295nm and it was found to be very high Ka∼1.39×10(7) M(-1) in case of ABG complex as compared to GlcNAc only Ka∼1.01×10(4) M(-1) with the phenomenon proven to be due to glycocluster effect. Copyright © 2016 Elsevier Inc. All rights reserved.

Staging properties of potassium-ammonia ternary graphite intercalation compounds at high ammonia pressure

Science.gov (United States)

Qian, X. W.; Solin, S. A.

1989-04-01

The pressure dependence of the (00l) x-ray diffraction patterns of the ternary graphite intercalation compound K(NH3)xC24 has been studied in the range 0.5-11 kbar (for which x~4.5) using a diamond anvil cell. A special apparatus for loading the cell with liquid ammonia at room temperature has been constructed and is briefly described. In these experiments, the pressure-transmitting fluid was also an intercalant, namely ammonia. Therefore, the chemical potential of this species was linearly coupled to the applied pressure in contrast to the usual case where the pressure-transmitting fluid is chemically passive. The pressure dependences of the basal spacings and of the relative intensities of key reflections have been measured, as have the compressibilities of the stage-1 and stage-2 components of the two-phase system. Basal-spacing anomalies and anomalies in the relative intensities occur at pressures of ~3.5 and 8.0 kbar and are tentatively attributed to in-plane coordination changes in the potassium-ammonia ratio. Using thermodynamic arguments and Le Chatelier's principle we show quantitatively that a staging phase transition from pure stage-1 phase to an admixture of stage-1 and stage-2 is expected with increased pressure above 10 bar in agreement with experiment. The saturation ammonia compositions (x values) of the admixed stages are found to be 4.5 and 5.4 for the stage-1 and -2 components, respectively. This result is interpreted as evidence that the composition is not sterically limited but is determined by the binding energy of ammonia for potassium and by the perturbation to this energy from the guest-host interaction.

Mechanism of ammonia excretion in the freshwater leech Nephelopsis obscura: characterization of a primitive Rh protein and effects of high environmental ammonia

Science.gov (United States)

Quijada-Rodriguez, Alex R.; Treberg, Jason R.

2015-01-01

Remarkably little is known about nitrogenous excretion in freshwater invertebrates. In the current study, the nitrogen excretion mechanism in the carnivorous ribbon leech, Nephelopsis obscura, was investigated. Excretion experiments showed that the ribbon leech is ammonotelic, excreting 166.0 ± 8.6 nmol·grams fresh weight (gFW)−1·h−1 ammonia and 14.7 ± 1.9 nmol·gFW−1·h−1 urea. Exposure to high and low pH hampered and enhanced, respectively, ammonia excretion rates, indicating an acid-linked ammonia trapping mechanism across the skin epithelia. Accordingly, compared with body tissues, the skin exhibited elevated mRNA expression levels of a newly identified Rhesus protein and at least in tendency the Na+/K+-ATPase. Pharmacological experiments and enzyme assays suggested an ammonia excretion mechanism that involves the V-ATPase, Na+/K+-ATPase, and carbonic anhydrase, but not necessarily a functional microtubule system. Most importantly, functional expression studies of the identified Rh protein cloned from leech skin tissue revealed an ammonia transport capability of this protein when expressed in yeast. The leech Rh-ammonia transporter (NoRhp) is a member of the primitive Rh protein family, which is a sister group to the common ancestor of vertebrate ammonia-transporting Rh proteins. Exposure to high environmental ammonia (HEA) caused a new adjustment of body ammonia, accompanied with a decrease in NoRhp and Na+/K+-ATPase mRNA levels, but unaltered ammonia excretion rates. To our knowledge, this is only the second comprehensive study regarding the ammonia excretion mechanisms in a freshwater invertebrate, but our results show that basic processes of ammonia excretion appear to also be comparable to those found in freshwater fish, suggesting an early evolution of ionoregulatory mechanisms in freshwater organisms. PMID:26180186

Ammonia Generation via a Graphene-Coated Nickel Catalyst

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Fei Lu

2017-05-01

Full Text Available A novel graphene-coated Ni electrode was developed in this investigation to improve corrosion resistance while unexpectedly enhancing the ammonia generation rate in the electrochemically induced urea to ammonia (eU2A process, which is an electrochemical onsite ammonia generation method. The development of the electrode is crucial for the eU2A reactions since in the ammonia generation process, the concentration of ammonia is inevitably high on the surface of the electrode, leading to severe corrosion of the electrode and the loss of generated ammonia as well. In this paper, the graphene was derived from raw coal by using the chemical vapor deposition method and self-lifted onto a Ni electrode to form a protective layer for corrosion prevention. Transmission electron microscopy showed the synthesized graphene had few-layers and Raman spectroscopy indicated that the coating of graphene was stable during the eU2A reaction. As a result, the ammonia corrosion of the Ni electrode was dramatically reduced by ~20 times with the graphene coating method. More importantly, a higher ammonia generation rate (~2 times was achieved using the graphene-coated Ni working electrode compared to a bare Ni electrode in the eU2A process.

Eating 'Junk-Food' Produces Rapid and Long-Lasting Increases in NAc CP-AMPA Receptors: Implications for Enhanced Cue-Induced Motivation and Food Addiction.

Science.gov (United States)

Oginsky, Max F; Goforth, Paulette B; Nobile, Cameron W; Lopez-Santiago, Luis F; Ferrario, Carrie R

2016-12-01

Urges to eat are influenced by stimuli in the environment that are associated with food (food cues). Obese people are more sensitive to food cues, reporting stronger craving and consuming larger portions after food cue exposure. The nucleus accumbens (NAc) mediates cue-triggered motivational responses, and activations in the NAc triggered by food cues are stronger in people who are susceptible to obesity. This has led to the idea that alterations in NAc function similar to those underlying drug addiction may contribute to obesity, particularly in obesity-susceptible individuals. Motivational responses are mediated in part by NAc AMPA receptor (AMPAR) transmission, and recent work shows that cue-triggered motivation is enhanced in obesity-susceptible rats after 'junk-food' diet consumption. Therefore, here we determined whether NAc AMPAR expression and function is increased by 'junk-food' diet consumption in obesity-susceptible vs -resistant populations using both outbred and selectively bred models of susceptibility. In addition, cocaine-induced locomotor activity was used as a general 'read out' of mesolimbic function after 'junk-food' consumption. We found a sensitized locomotor response to cocaine in rats that gained weight on a 'junk-food' diet, consistent with greater responsivity of mesolimbic circuits in obesity-susceptible groups. In addition, eating 'junk-food' increased NAc calcium-permeable-AMPAR (CP-AMPAR) function only in obesity-susceptible rats. This increase occurred rapidly, persisted for weeks after 'junk-food' consumption ceased, and preceded the development of obesity. These data are considered in light of enhanced cue-triggered motivation and striatal function in obesity-susceptible rats and the role of NAc CP-AMPARs in enhanced motivation and addiction.

Safety assessment of ammonia as a transport fuel

Energy Technology Data Exchange (ETDEWEB)

Duijm, N.J.; Markert, F.; Lundtang paulsen, Jette

2005-02-01

This report describes the safety study performed as part of the EU supported project 'Ammonia Cracking for Clean Electric Power Technology' The study addresses the following activities: safety of operation of the ammonia-powered vehicle under normal and accident (collision) conditions, safety of transport of ammonia to the refuelling stations and safety of the activities at the refuelling station (unloading and refuelling). Comparisons are made between the safety of using ammonia and the safety of other existing or alternative fuels. The conclusion is that the hazards in relation to ammonia need to be controlled by a combination of technical and regulatory measures. The most important requirements are: - Advanced safety systems in the vehicle - Additional technical measures and regulations are required to avoid releases in maintenance workshops and unauthorised maintenance on the fuel system - Road transport of ammonia to refuelling stations in refrigerated form - Sufficient safety zones between refuelling stations and residential or otherwise public areas. When these measures are applied, the use of ammonia as a transport fuel wouldnt cause more risks than currently used fuels (using current practice). (au)

TaNAC1 acts as a negative regulator of stripe rust resistance in wheat, enhances susceptibility to Pseudomonas syringae, and promotes lateral root development in transgenic Arabidopsis thaliana

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Fengtao eWang

2015-02-01

Full Text Available Plant-specific NAC transcription factors constitute a large family and play important roles in regulating plant developmental processes and responses to environmental stresses, but only some of them have been investigated for effects on disease reaction in cereal crops. Virus-induced gene silencing (VIGS is an effective strategy for rapid functional analysis of genes in plant tissues. In this study, TaNAC1, encoding a new member of the NAC1 subgroup, was cloned from bread wheat and characterized. It is a transcription factor localized in the cell nucleus, and contains an activation domain in its C-terminal. TaNAC1 was strongly expressed in wheat roots and was involved in responses to infection by the obligate pathogen Puccinia striiformis f. sp. tritici and defense-related hormone treatments such as salicylic acid, methyl jasmonate and ethylene. Knockdown of TaNAC1 with barley stripe mosaic virus-induced gene silencing (BSMV-VIGS enhanced stripe rust resistance. TaNAC1-overexpression in Arabidopsis plants gave enhanced susceptibility, attenuated systemic-acquired resistance to Pseudomonas syringae DC3000, and promoted lateral root development. Jasmonic acid-signaling pathway genes PDF1.2 and ORA59 were constitutively expressed in transgenic plants. TaNAC1 overexpression suppressed the expression levels of resistance-related genes PR1 and PR2 involved in SA signaling and AtWRKY70, which functions as a connection node between the JA- and SA-signaling pathways. Collectively, TaNAC1 is a novel NAC member of the NAC1 subgroup, negatively regulates plant disease resistance, and may modulate plant JA- and SA-signaling defense cascades.

Ceramic piezoelectric materials

International Nuclear Information System (INIS)

Kaszuwara, W.

2004-01-01

Ceramic piezoelectric materials conert reversibility electric energy into mechanical energy. In the presence of electric field piezoelectric materials exhibit deformations up to 0.15% (for single crystals up to 1.7%). The deformation energy is in the range of 10 2 - 10 3 J/m 3 and working frequency can reach 10 5 Hz. Ceramic piezoelectric materials find applications in many modern disciplines such as: automatics, micromanipulation, measuring techniques, medical diagnostics and many others. Among the variety of ceramic piezoelectric materials the most important appear to be ferroelectric materials such as lead zirconate titanate so called PZT ceramics. Ceramic piezoelectric materials can be processed by methods widely applied for standard ceramics, i.e. starting from simple precursors e.g. oxides. Application of sol-gel method has also been reported. Substantial drawback for many applications of piezoelectric ceramics is their brittleness, thus much effort is currently being put in the development of piezoelectric composite materials. Other important research directions in the field of ceramic piezoelectric materials composite development of lead free materials, which can exhibit properties similar to the PZT ceramics. Among other directions one has to state processing of single crystals and materials having texture or gradient structure. (author)

Testing method for ceramic armour and bare ceramic tiles

NARCIS (Netherlands)

Carton, E.P.; Roebroeks, G.H.J.J.

2016-01-01

TNO developed an alternative, more configuration independent ceramic test method than the Depth-of-Penetration test method. In this alternative test ceramic tiles and ceramic based armour are evaluated as target without a semi-infinite backing layer. An energy approach is chosen to evaluate and rank

Testing method for ceramic armor and bare ceramic tiles

NARCIS (Netherlands)

Carton, E.P.; Roebroeks, G.H.J.J.

2014-01-01

TNO has developed an alternative, more configuration independent ceramic test method than the standard Depth-of-Penetration test method. In this test ceramic tiles and ceramic based armor are evaluated as target without a semi-infinite backing layer. An energy approach is chosen to evaluate and rank

Study of Ammonia Emissions in a Ventilated Pig Pen

DEFF Research Database (Denmark)

Rong, Li

Pig productions cause a wide emission of odors, such as ammonia (NH3), hydrogen sulfide (H2S), and methane (CH4). Ammonia is one of the most important emissions for evaluating the air quality either in animal buildings or atmospheric environment. In studies of ammonia emission from animal buildings...... emission rate was measured in a wind tunnel under different airflow and ammonium solution temperatures. This investigation provides a general understanding for the influence of velocity, turbulence intensity and temperature on the ammonia emissions. The relationship between ammonia emissions and boundary...... through the air-liquid interface is suggested from vapor-liquid equilibrium properties of ammonia water. Furthermore, the effects of airflow and temperature on ammonia mass transfer coefficient are also analyzed under different concentration boundary conditions determined by various Henry’s law constant...

Glycopyrrolate in toxic exposure to ammonia gas

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Bhalla A

2011-01-01

Full Text Available Ammonia (NH 3 is a highly water-soluble, colorless, irritant gas with a unique pungent odor. Liquid ammonia stored under high pressure is still widely used for refrigeration in cold stores used for storing grains. Severe toxicity may occur following accidental exposure. We report an interesting case of accidental exposure to ammonia treated with glycopyrrolate along with other supportive measures.

Comprehensive genome-wide survey, genomic constitution and expression profiling of the NAC transcription factor family in foxtail millet (Setaria italica L..

Directory of Open Access Journals (Sweden)

Swati Puranik

Full Text Available The NAC proteins represent a major plant-specific transcription factor family that has established enormously diverse roles in various plant processes. Aided by the availability of complete genomes, several members of this family have been identified in Arabidopsis, rice, soybean and poplar. However, no comprehensive investigation has been presented for the recently sequenced, naturally stress tolerant crop, Setaria italica (foxtail millet that is famed as a model crop for bioenergy research. In this study, we identified 147 putative NAC domain-encoding genes from foxtail millet by systematic sequence analysis and physically mapped them onto nine chromosomes. Genomic organization suggested that inter-chromosomal duplications may have been responsible for expansion of this gene family in foxtail millet. Phylogenetically, they were arranged into 11 distinct sub-families (I-XI, with duplicated genes fitting into one cluster and possessing conserved motif compositions. Comparative mapping with other grass species revealed some orthologous relationships and chromosomal rearrangements including duplication, inversion and deletion of genes. The evolutionary significance as duplication and divergence of NAC genes based on their amino acid substitution rates was understood. Expression profiling against various stresses and phytohormones provides novel insights into specific and/or overlapping expression patterns of SiNAC genes, which may be responsible for functional divergence among individual members in this crop. Further, we performed structure modeling and molecular simulation of a stress-responsive protein, SiNAC128, proffering an initial framework for understanding its molecular function. Taken together, this genome-wide identification and expression profiling unlocks new avenues for systematic functional analysis of novel NAC gene family candidates which may be applied for improvising stress adaption in plants.

Comprehensive genome-wide survey, genomic constitution and expression profiling of the NAC transcription factor family in foxtail millet (Setaria italica L.).

Science.gov (United States)

Puranik, Swati; Sahu, Pranav Pankaj; Mandal, Sambhu Nath; B, Venkata Suresh; Parida, Swarup Kumar; Prasad, Manoj

2013-01-01

The NAC proteins represent a major plant-specific transcription factor family that has established enormously diverse roles in various plant processes. Aided by the availability of complete genomes, several members of this family have been identified in Arabidopsis, rice, soybean and poplar. However, no comprehensive investigation has been presented for the recently sequenced, naturally stress tolerant crop, Setaria italica (foxtail millet) that is famed as a model crop for bioenergy research. In this study, we identified 147 putative NAC domain-encoding genes from foxtail millet by systematic sequence analysis and physically mapped them onto nine chromosomes. Genomic organization suggested that inter-chromosomal duplications may have been responsible for expansion of this gene family in foxtail millet. Phylogenetically, they were arranged into 11 distinct sub-families (I-XI), with duplicated genes fitting into one cluster and possessing conserved motif compositions. Comparative mapping with other grass species revealed some orthologous relationships and chromosomal rearrangements including duplication, inversion and deletion of genes. The evolutionary significance as duplication and divergence of NAC genes based on their amino acid substitution rates was understood. Expression profiling against various stresses and phytohormones provides novel insights into specific and/or overlapping expression patterns of SiNAC genes, which may be responsible for functional divergence among individual members in this crop. Further, we performed structure modeling and molecular simulation of a stress-responsive protein, SiNAC128, proffering an initial framework for understanding its molecular function. Taken together, this genome-wide identification and expression profiling unlocks new avenues for systematic functional analysis of novel NAC gene family candidates which may be applied for improvising stress adaption in plants.

Interactions between plant RING-H2 and plant-specific NAC (NAM/ATAF1/2/CUC2) proteins: RING-H2 molecular specificity and cellular localization

DEFF Research Database (Denmark)

Greve, Krestine; Bravo Munoz, Tanja La Cour; Jensen, Michael Krogh

2003-01-01

RING miduler, NAC transkriptionsfatorer, abscisinsyre inducerbar, proteinnedbrydning, subcellulær lo......RING miduler, NAC transkriptionsfatorer, abscisinsyre inducerbar, proteinnedbrydning, subcellulær lo...

The importance of the ammonia purification process in ammonia-water absorption systems

International Nuclear Information System (INIS)

Fernandez-Seara, Jose; Sieres, Jaime

2006-01-01

Practical experience in working with ammonia-water absorption systems shows that the ammonia purification process is a crucial issue in order to obtain an efficient and reliable system. In this paper, the detrimental effects of the residual water content in the vapour refrigerant are described and quantified based on the system design variables that determine the effectiveness of the purification process. The study has been performed considering a single stage system with a distillation column with complete condensation. The ammonia purification effectiveness of the column is analysed in terms of the efficiencies in the stripping and rectifying sections and the reflux ratio. By varying the efficiencies from 0 to 1, systems with neither the rectifying nor stripping section, with either the rectifying or stripping section, or with both sections can be considered. The impact of the ammonia purification process on the absorption system performance is studied based on the column efficiencies and reflux ratio; and its effects on refrigerant concentration, system COP, system pressures and main system mass flow rates and concentrations are analysed. When the highest efficiency rectifying sections are used a combination of generation temperature and reflux ratio which leads to optimum COP values is found. The analysis covers different operating conditions with air and water cooled systems from refrigeration to air conditioning applications by changing the evaporation temperature. The importance of rectification in each kind of application is evaluated

FIBROUS CERAMIC-CERAMIC COMPOSITE MATERIALS PROCESSING AND PROPERTIES

OpenAIRE

Naslain , R.

1986-01-01

The introduction of continuous fibers in a ceramic matrix can improve its toughness, if the fiber-matrix bonding is weak enough, due to matrix microcracking and fiber pull-out. Ceramic-ceramic composite materials are processed according to liquid or gas phase techniques. The most important are made of glass, carbide, nitride or oxide matrices reinforced with carbon, SiC or Al2O3 fibers.

Release of ammonia from HAN-type PHA

International Nuclear Information System (INIS)

Zamecnik, J.R.

1992-01-01

A preliminary design basis for ammonia scrubbers in the DWPF has been issued. This design basis is based on a theoretical model of ammonia evolution from the SRAT, SME and RCT. It is desirable to acquire actual process data on ammonia evolution prior to performing detailed design of scrubbers for DWPF. The evolution of ammonia from the SRAT and SME in the Integrated DWPF Melter System (IDMS) was investigated during the HM4 run. In this run, Precipitate Hydrolysis Aqueous (PHA), which was made in the Precipitate Hydrolysis Experimental Facility (PHEF) using the HAN (hydroxylamine nitrate) process was used, thus resulting in PHA with a high concentration of ammonium ion

Converting Wind Energy to Ammonia at Lower Pressure

International Nuclear Information System (INIS)

Malmali, Mahdi; Reese, Michael; McCormick, Alon V.; Cussler, E. L.

2017-01-01

Renewable wind energy can be used to make ammonia. However, wind-generated ammonia costs about twice that made from a traditional fossil-fuel driven process. To reduce the production cost, we replace the conventional ammonia condensation with a selective absorber containing metal halides, e.g., calcium chloride, operating at near synthesis temperatures. With this reaction-absorption process, ammonia can be synthesized at 20 bar from air, water, and wind-generated electricity, with rates comparable to the conventional process running at 150–300 bar. In our reaction-absorption process, the rate of ammonia synthesis is now controlled not by the chemical reaction but largely by the pump used to recycle the unreacted gases. The results suggest an alternative route to distributed ammonia manufacture which can locally supply nitrogen fertilizer and also a method to capture stranded wind energy as a carbon-neutral liquid fuel.

O-linked-N-acetylglucosamine modification of mammalian Notch receptors by an atypical O-GlcNAc transferase Eogt1

Energy Technology Data Exchange (ETDEWEB)

Sakaidani, Yuta [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan); Ichiyanagi, Naoki [Department of Applied Molecular Biosciences, Nagoya University Graduate School of Bioagricultural Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Saito, Chika; Nomura, Tomoko [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan); Ito, Makiko [Department of Applied Molecular Biosciences, Nagoya University Graduate School of Bioagricultural Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Nishio, Yosuke [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan); Nadano, Daita; Matsuda, Tsukasa [Department of Applied Molecular Biosciences, Nagoya University Graduate School of Bioagricultural Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Furukawa, Koichi [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan); Okajima, Tetsuya, E-mail: tokajima@med.nagoya-u.ac.jp [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan); Department of Applied Molecular Biosciences, Nagoya University Graduate School of Bioagricultural Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan)

2012-03-02

Highlights: Black-Right-Pointing-Pointer We characterized A130022J15Rik (Eogt1)-a mouse gene homologous to Drosophila Eogt. Black-Right-Pointing-Pointer Eogt1 encodes EGF domain O-GlcNAc transferase. Black-Right-Pointing-Pointer Expression of Eogt1 in Drosophila rescued the cell-adhesion defect in the Eogt mutant. Black-Right-Pointing-Pointer O-GlcNAcylation reaction in the secretory pathway is conserved through evolution. -- Abstract: O-linked-{beta}-N-acetylglucosamine (O-GlcNAc) modification is a unique cytoplasmic and nuclear protein modification that is common in nearly all eukaryotes, including filamentous fungi, plants, and animals. We had recently reported that epidermal growth factor (EGF) repeats of Notch and Dumpy are O-GlcNAcylated by an atypical O-GlcNAc transferase, EOGT, in Drosophila. However, no study has yet shown whether O-GlcNAcylation of extracellular proteins is limited to insects such as Drosophila or whether it occurs in other organisms, including mammals. Here, we report the characterization of A130022J15Rik, a mouse gene homolog of Drosophila Eogt (Eogt 1). Enzymatic analysis revealed that Eogt1 has a substrate specificity similar to that of Drosophila EOGT, wherein the Thr residue located between the fifth and sixth conserved cysteines of the folded EGF-like domains is modified. This observation is supported by the fact that the expression of Eogt1 in Drosophila rescued the cell-adhesion defect caused by Eogt downregulation. In HEK293T cells, Eogt1 expression promoted modification of Notch1 EGF repeats by O-GlcNAc, which was further modified, at least in part, by galactose to generate a novel O-linked-N-acetyllactosamine structure. These results suggest that Eogt1 encodes EGF domain O-GlcNAc transferase and that O-GlcNAcylation reaction in the secretory pathway is a fundamental biochemical process conserved through evolution.

O-linked-N-acetylglucosamine modification of mammalian Notch receptors by an atypical O-GlcNAc transferase Eogt1

International Nuclear Information System (INIS)

Sakaidani, Yuta; Ichiyanagi, Naoki; Saito, Chika; Nomura, Tomoko; Ito, Makiko; Nishio, Yosuke; Nadano, Daita; Matsuda, Tsukasa; Furukawa, Koichi; Okajima, Tetsuya

2012-01-01

Highlights: ► We characterized A130022J15Rik (Eogt1)—a mouse gene homologous to Drosophila Eogt. ► Eogt1 encodes EGF domain O-GlcNAc transferase. ► Expression of Eogt1 in Drosophila rescued the cell-adhesion defect in the Eogt mutant. ► O-GlcNAcylation reaction in the secretory pathway is conserved through evolution. -- Abstract: O-linked-β-N-acetylglucosamine (O-GlcNAc) modification is a unique cytoplasmic and nuclear protein modification that is common in nearly all eukaryotes, including filamentous fungi, plants, and animals. We had recently reported that epidermal growth factor (EGF) repeats of Notch and Dumpy are O-GlcNAcylated by an atypical O-GlcNAc transferase, EOGT, in Drosophila. However, no study has yet shown whether O-GlcNAcylation of extracellular proteins is limited to insects such as Drosophila or whether it occurs in other organisms, including mammals. Here, we report the characterization of A130022J15Rik, a mouse gene homolog of Drosophila Eogt (Eogt 1). Enzymatic analysis revealed that Eogt1 has a substrate specificity similar to that of Drosophila EOGT, wherein the Thr residue located between the fifth and sixth conserved cysteines of the folded EGF-like domains is modified. This observation is supported by the fact that the expression of Eogt1 in Drosophila rescued the cell-adhesion defect caused by Eogt downregulation. In HEK293T cells, Eogt1 expression promoted modification of Notch1 EGF repeats by O-GlcNAc, which was further modified, at least in part, by galactose to generate a novel O-linked-N-acetyllactosamine structure. These results suggest that Eogt1 encodes EGF domain O-GlcNAc transferase and that O-GlcNAcylation reaction in the secretory pathway is a fundamental biochemical process conserved through evolution.

Durability of feldspathic veneering ceramic on glass-infiltrated alumina ceramics after long-term thermocycling.

Science.gov (United States)

Mesquita, A M M; Ozcan, M; Souza, R O A; Kojima, A N; Nishioka, R S; Kimpara, E T; Bottino, M A

2010-01-01

This study compared the bond strength durability of a feldspathic veneering ceramic to glass-infiltrated reinforced ceramics in dry and aged conditions. Disc shaped (thickness: 4 mm, diameter: 4 mm) of glass-infiltrated alumina (In-Ceram Alumina) and glass-infiltrated alumina reinforced by zirconia (In-Ceram Zirconia) core ceramic specimens (N=48, N=12 per groups) were constructed according to the manufacturers' recommendations. Veneering ceramic (VITA VM7) was fired onto the core ceramics using a mold. The core-veneering ceramic assemblies were randomly divided into two conditions and tested either immediately after specimen preparation (Dry) or following 30000 thermocycling (5-55 ºC±1; dwell time: 30 seconds). Shear bond strength test was performed in a universal testing machine (cross-head speed: 1 mm/min). Failure modes were analyzed using optical microscope (x20). The bond strength data (MPa) were analyzed using ANOVA (α=0.05). Thermocycling did not decrease the bond strength results for both In-Ceram Alumina (30.6±8.2 MPa; P=0.2053) and In-Ceram zirconia (32.6±9 MPa; P=0.3987) core ceramic-feldspathic veneering ceramic combinations when compared to non-aged conditions (28.1±6.4 MPa, 29.7±7.3 MPa, respectively). There were also no significant differences between adhesion of the veneering ceramic to either In-Ceram Alumina or In-Ceram Zirconia ceramics (P=0.3289). Failure types were predominantly a mixture of adhesive failure between the veneering and the core ceramic together with cohesive fracture of the veneering ceramic. Long-term thermocycling aging conditions did not impair the adhesion of the veneering ceramic to the glass-infiltrated alumina core ceramics tested.

Ammonia Affects Astroglial Proliferation in Culture

Science.gov (United States)

Bodega, Guillermo; Segura, Berta; Ciordia, Sergio; Mena, María del Carmen; López-Fernández, Luis Andrés; García, María Isabel; Trabado, Isabel; Suárez, Isabel

2015-01-01

Primary cultures of rat astroglial cells were exposed to 1, 3 and 5 mM NH4Cl for up to 10 days. Dose- and time-dependent reductions in cell numbers were seen, plus an increase in the proportion of cells in the S phase. The DNA content was reduced in the treated cells, and BrdU incorporation diminished. However, neither ammonia nor ammonia plus glutamine had any effect on DNA polymerase activity. iTRAQ analysis showed that exposure to ammonia induced a significant reduction in histone and heterochromatin protein 1 expression. A reduction in cell viability was also noted. The ammonia-induced reduction of proliferative activity in these cultured astroglial cells seems to be due to a delay in the completion of the S phase provoked by the inhibition of chromatin protein synthesis. PMID:26421615

Ammonia Affects Astroglial Proliferation in Culture.

Directory of Open Access Journals (Sweden)

Guillermo Bodega

Full Text Available Primary cultures of rat astroglial cells were exposed to 1, 3 and 5 mM NH4Cl for up to 10 days. Dose- and time-dependent reductions in cell numbers were seen, plus an increase in the proportion of cells in the S phase. The DNA content was reduced in the treated cells, and BrdU incorporation diminished. However, neither ammonia nor ammonia plus glutamine had any effect on DNA polymerase activity. iTRAQ analysis showed that exposure to ammonia induced a significant reduction in histone and heterochromatin protein 1 expression. A reduction in cell viability was also noted. The ammonia-induced reduction of proliferative activity in these cultured astroglial cells seems to be due to a delay in the completion of the S phase provoked by the inhibition of chromatin protein synthesis.

Ammonium recruitment and ammonia transport by E. coli ammonia channel AmtB

DEFF Research Database (Denmark)

Nygaard, Thomas Pedersen; Rovira, C.; Peters, Günther H.j.

2006-01-01

To investigate substrate recruitment and transport across the Escherichia coli Ammonia transporter B (AmtB) protein, we performed molecular dynamics simulations of the AmtB trimer. We have identified residues important in recruitment of ammonium and intraluminal binding sites selective of ammonium......, which provide a means of cation selectivity. Our results indicate that A162 guides translocation of an extraluminal ammonium into the pore lumen. We propose a mechanism for transporting the intraluminally recruited proton back to periplasm. Our mechanism conforms to net transport of ammonia and can...

Ammonia concentrations in canine whole blood, EDTA-anticoagulated whole blood, and plasma measured by use of a point-of-care ammonia meter.

Science.gov (United States)

Odunayo, Adesola; Tobias, Karen M; Okafor, Chika C; Flatland, Bente

2017-11-01

OBJECTIVE To investigate the use of canine whole blood (WB) for measurement of ammonia concentration by use of a point-of-care ammonia meter and to compare results of measuring ammonia concentrations in WB, EDTA-anticoagulated WB, and plasma. ANIMALS 40 client-owned dogs. PROCEDURES A blood sample (2 mL) was obtained from each dog. One drop of WB was immediately applied to a test strip for evaluation with an ammonia meter. The remainder of the blood sample was placed in an EDTA-containing tube, and 1 drop of EDTA-anticoagulated WB was applied to a test strip. The remaining EDTA-anticoagulated WB sample was centrifuged, and the plasma was harvested and placed on ice. One drop of plasma was applied to a test strip; the remainder of the plasma sample was transported on ice and used for ammonia measurement with a reference laboratory instrument. All samples were tested within 1 hour after sample collection. Results were evaluated to detect significant differences in ammonia concentration. RESULTS Ammonia concentrations did not differ significantly between WB and EDTA-anticoagulated WB and between plasma samples measured with the meter and reference laboratory instrument. However, median ammonia concentration was significantly higher in plasma than in WB or EDTA-anti-coagulated WB. CONCLUSIONS AND CLINICAL RELEVANCE Anticoagulant-free WB was a valid sample for measurement by use of the ammonia meter. Plasma samples had higher ammonia concentrations than did WB samples. Results for each sample type should be interpreted by use of specimen- and method-specific reference intervals.

Changes of ammonia, urea contents and transaminase activity in the body during aerial exposure and ammonia loading in Chinese loach Paramisgurnus dabryanus.

Science.gov (United States)

Zhang, Yun-Long; Zhang, Hai-Long; Wang, Ling-Yu; Gu, Bei-Yi; Fan, Qi-Xue

2017-04-01

The Paramisgurnus dabryanus was exposed to 30 mmol L -1 NH 4 Cl solution and air to assessing the change of body ammonia and urea contents and the activities of alanine aminotransferase (ALT) and aspartate transaminase (AST). After 48 h of ammonia exposure, ammonia concentration in the plasma, brain, liver and muscle were 3.3-fold, 5.6-fold, 3.5-fold and 4.2-fold, respectively, those of the control values. Plasma, brain, liver and muscle ammonia concentrations increased to 2.2-fold, 3.3-fold, 2.5-fold and 2.9-fold, respectively, those of control values in response to 48 h of aerial exposure. Within the given treatment (ammonia or aerial exposure), there was no change in plasma, brain and liver urea concentrations between exposure durations. The plasma ALT activity was significantly affected by exposure time during aerial exposure, while the liver ALT activity was not affected by ammonia or aerial exposure. Exposure to NH 4 Cl or air had no effect on either plasma or liver AST activity. Our results suggested that P. dabryanus could accumulate quite high level of internal ammonia because of the high ammonia tolerance in its cells and tissues, and NH 3 volatilization would be a possible ammonia detoxification strategy in P. dabryanus. Urea synthesis was not an effective mechanism to deal with environmental or internal ammonia problem. The significant increase of ALT activity in plasma during aerial exposure, indicating that alanine synthesis through certain amino acid catabolism may be subsistent in P. dabryanus.

NAC-1 cask dose rate calculations for LWR spent fuel

International Nuclear Information System (INIS)

CARLSON, A.B.

1999-01-01

A Nuclear Assurance Corporation nuclear fuel transport cask, NAC-1, is being considered as a transport and storage option for spent nuclear fuel located in the B-Cell of the 324 Building. The loaded casks will be shipped to the 200 East Area Interim Storage Area for dry interim storage. Several calculations were performed to assess the photon and neutron dose rates. This report describes the analytical methods, models, and results of this investigation

CADDIS Volume 2. Sources, Stressors and Responses: Ammonia - Simple Conceptual Diagram

Science.gov (United States)

Introduction to the ammonia module, when to list ammonia as a candidate cause, ways to measure ammonia, simple and detailed conceptual diagrams for ammonia, literature reviews and references for the ammonia module.

CADDIS Volume 2. Sources, Stressors and Responses: Ammonia - Detailed Conceptual Diagram

Science.gov (United States)

Introduction to the ammonia module, when to list ammonia as a candidate cause, ways to measure ammonia, simple and detailed conceptual diagrams for ammonia, literature reviews and references for the ammonia module.

Ceramic Technology Project

Energy Technology Data Exchange (ETDEWEB)

1992-03-01

The Ceramic Technology Project was developed by the USDOE Office of Transportation Systems (OTS) in Conservation and Renewable Energy. This project, part of the OTS's Materials Development Program, was developed to meet the ceramic technology requirements of the OTS's automotive technology programs. Significant accomplishments in fabricating ceramic components for the USDOE and NASA advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. These programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. A five-year project plan was developed with extensive input from private industry. In July 1990 the original plan was updated through the estimated completion of development in 1993. The objective is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities.

Skeletal muscle O-GlcNAc transferase is important for muscle energy homeostasis and whole-body insulin sensitivity

Directory of Open Access Journals (Sweden)

Hao Shi

2018-05-01

Full Text Available Objective: Given that cellular O-GlcNAcylation levels are thought to be real-time measures of cellular nutrient status and dysregulated O-GlcNAc signaling is associated with insulin resistance, we evaluated the role of O-GlcNAc transferase (OGT, the enzyme that mediates O-GlcNAcylation, in skeletal muscle. Methods: We assessed O-GlcNAcylation levels in skeletal muscle from obese, type 2 diabetic people, and we characterized muscle-specific OGT knockout (mKO mice in metabolic cages and measured energy expenditure and substrate utilization pattern using indirect calorimetry. Whole body insulin sensitivity was assessed using the hyperinsulinemic euglycemic clamp technique and tissue-specific glucose uptake was subsequently evaluated. Tissues were used for histology, qPCR, Western blot, co-immunoprecipitation, and chromatin immunoprecipitation analyses. Results: We found elevated levels of O-GlcNAc-modified proteins in obese, type 2 diabetic people compared with well-matched obese and lean controls. Muscle-specific OGT knockout mice were lean, and whole body energy expenditure and insulin sensitivity were increased in these mice, consistent with enhanced glucose uptake and elevated glycolytic enzyme activities in skeletal muscle. Moreover, enhanced glucose uptake was also observed in white adipose tissue that was browner than that of WT mice. Interestingly, mKO mice had elevated mRNA levels of Il15 in skeletal muscle and increased circulating IL-15 levels. We found that OGT in muscle mediates transcriptional repression of Il15 by O-GlcNAcylating Enhancer of Zeste Homolog 2 (EZH2. Conclusions: Elevated muscle O-GlcNAc levels paralleled insulin resistance and type 2 diabetes in humans. Moreover, OGT-mediated signaling is necessary for proper skeletal muscle metabolism and whole-body energy homeostasis, and our data highlight O-GlcNAcylation as a potential target for ameliorating metabolic disorders. Keywords: O-GlcNAc signaling, Type 2 diabetes, N

Creep in ceramics

CERN Document Server

Pelleg, Joshua

2017-01-01

This textbook is one of its kind, since there are no other books on Creep in Ceramics. The book consist of two parts: A and B. In part A general knowledge of creep in ceramics is considered, while part B specifies creep in technologically important ceramics. Part B covers creep in oxide ceramics, carnides and nitrides. While covering all relevant information regarding raw materials and characterization of creep in ceramics, the book also summarizes most recent innovations and developments in this field as a result of extensive literature search.

Sensitive Ceramics

DEFF Research Database (Denmark)

2014-01-01

Sensitive Ceramics is showing an interactive digital design tool for designing wall like composition with 3d ceramics. The experiment is working on two levels. One which has to do with designing compositions and patterns in a virtual 3d universe based on a digital dynamic system that responds on ...... with realizing the modules in ceramics by 3d printing directly in porcelain with a RapMan printer that coils up the 3d shape in layers. Finally the ceramic modules are mounted in a laser cut board that reflects the captured composition of the movement of the hands....

Performance Study of Ceramic Filter Module in Recirculated Aquaculture System (RAS)

Science.gov (United States)

Ng, L. Y.; Ng, C. Y.

2017-06-01

The growth of world population has led to significant increase in seafood demand over the world. Aquaculture has been widely accepted by many countries to increase the seafood production owing to the decline of natural seafood resources. The aquaculture productivity, however, is directly linked to the pond water quality. In this study, attempts were made to employ ceramic micro-filter to improve the pond water quality through filtration processes. There were two batches of filtration processes, short term (1 hour) and long term (48 hours). Significant improvements on real pond water quality were recorded through the short term microfiltration process, which reduced turbidity (96%), total suspended solids (TSS) (80%), biochemical oxygen demand (BOD) (72%), chemical oxygen demand (COD) (55%), ammonia (60%), nitrate (96%) and phosphorus (83%). The long term filtration process also showed high efficiency in the removal of solid particle and organic matters. The results showed that all of the parameters were successfully reduced to acceptable ranges (turbidityfiltered pond water. Current study showed that the microfiltration using ceramic micro-filter has high potential to be used in recirculating aquaculture system throughout the aquaculture activities in order to maintain the pond water quality, thus, increase the survival rate of cultured species.

Hydrothermal oxidation of ammonia/organic waste mixtures

International Nuclear Information System (INIS)

Luan, Li; Proesmans, P.I.; Buelow, S.J.

1997-01-01

Hydrothermal oxidation is a promising new technology for the treatment of radioactive contaminated hazardous organic wastes. Los Alamos National Laboratory is currently evaluating this technology for the U. S. Department of Energy. In this paper, we present experimental results from the study of the hydrothermal oxidation of an ammonia/alcohol/uranium waste mixture. The use of a co-oxidant system consisting of hydrogen peroxide combined with nitrate is discussed. Experiments demonstrate near complete destruction of ammonia and organic compounds at 500 degrees C, 38 MPa, and 50 seconds reaction time. The ammonia and total organic carbon (TOC) concentrations in a waste simulant is reduced from 8,500 mg/L of ammonia and 12,500 mg/L TOC to 30 mg/L ammonia and less than 10 mg/L TOC. The major reaction products are CO 2 , N 2 , and a small amount of N 2 O. Comparison experiments with nitrate and hydrogen peroxide used individually show the advantage of the co-oxidant system

Improving The Efficiency Of Ammonia Electrolysis For Hydrogen Production

Science.gov (United States)

Palaniappan, Ramasamy

Given the abundance of ammonia in domestic and industrial wastes, ammonia electrolysis is a promising technology for remediation and distributed power generation in a clean and safe manner. Efficiency has been identified as one of the key issues that require improvement in order for the technology to enter the market phase. Therefore, this research was performed with the aim of improving the efficiency of hydrogen production by finding alternative materials for the cathode and electrolyte. 1. In the presence of ammonia the activity for hydrogen evolution reaction (HER) followed the trend Rh>Pt>Ru>Ni. The addition of ammonia resulted in lower rates for HER for Pt, Ru, and Ni, which have been attributed to competition from the ammonia adsorption reaction. 2. The addition of ammonia offers insight into the role of metal-hydrogen underpotential deposition (M-Hupd) on HER kinetics. In addition to offering competition via ammonia adsorption it resulted in fewer and weaker M-Hupd bonds for all metals. This finding substantiates the theory that M-Hupd bonds favor HER on Pt electrocatalyst. However, for Rh results suggest that M-Hupd bond may hinder the HER. In addition, the presence of unpaired valence shell electrons is suggested to provide higher activity for HER in the presence of ammonia. 3. Bimetals PtxM1-x (M = Ir, Ru, Rh, and Ni) offered lower overpotentials for HER compared to the unalloyed metals in the presence of ammonia. The activity of HER in the presence of ammonia follows the trend Pt-Ir>Pt-Rh>Pt-Ru>Pt-Ni. The higher activity of HER is attributed to the synergistic effect of the alloy, where ammonia adsorbs onto the more electropositive alloying metal leaving Pt available for Hupd formation and HER to take place. Additionally, this supports the theory that the presence of a higher number of unpaired electrons favors the HER in the presence of ammonia. 4. Potassium polyacrylate (PAA-K) was successfully used as a substitute for aqueous KOH for ammonia

Fabrication and testing of ceramic UO{sub 2} fuel - I-III. Part I; Izrada i ispitivanje keramickog goriva na bazi UO{sub 2}- I-III, I Deo

Energy Technology Data Exchange (ETDEWEB)

Novakovic, M [Institute of Nuclear Sciences Boris Kidric, Laboratorija za termotehniku reaktora, Vinca, Beograd (Serbia and Montenegro)

1961-12-15

The task described consists of the following: fabrication of UO{sub 2} with different granulation from uranyl nitrate by ammonia diuranate; determination of size and shape distributions of metal and ceramic powders; fabrication of sintered pressed samples UO{sub 2}; investigating the properties of sintered uranium dioxide dependent on the fabrication process; producing a vibrator for compacting UO{sub 2} powder. This volume includes reports on the first two tasks.

Regeneration of ammonia borane from polyborazylene

Science.gov (United States)

Sutton, Andrew; Gordon, John C; Ott, Kevin C; Burrell, Anthony K

2013-02-05

Method of producing ammonia borane, comprising providing a reagent comprising a dehydrogenated material in a suitable solvent; and combining the reagent with a reducing agent comprising hydrazine, a hydrazine derivative, or combinations thereof, in a reaction which produces a mixture comprising ammonia borane.

The EGF repeat-specific O-GlcNAc-transferase Eogt interacts with notch signaling and pyrimidine metabolism pathways in Drosophila.

Directory of Open Access Journals (Sweden)

Reto Müller

Full Text Available The O-GlcNAc transferase Eogt modifies EGF repeats in proteins that transit the secretory pathway, including Dumpy and Notch. In this paper, we show that the Notch ligands Delta and Serrate are also substrates of Eogt, that mutation of a putative UDP-GlcNAc binding DXD motif greatly reduces enzyme activity, and that Eogt and the cytoplasmic O-GlcNAc transferase Ogt have distinct substrates in Drosophila larvae. Loss of Eogt is larval lethal and disrupts Dumpy functions, but does not obviously perturb Notch signaling. To identify novel genetic interactions with eogt, we investigated dominant modification of wing blister formation caused by knock-down of eogt. Unexpectedly, heterozygosity for several members of the canonical Notch signaling pathway suppressed wing blister formation. And importantly, extensive genetic interactions with mutants in pyrimidine metabolism were identified. Removal of pyrimidine synthesis alleles suppressed wing blister formation, while removal of uracil catabolism alleles was synthetic lethal with eogt knock-down. Therefore, Eogt may regulate protein functions by O-GlcNAc modification of their EGF repeats, and cellular metabolism by affecting pyrimidine synthesis and catabolism. We propose that eogt knock-down in the wing leads to metabolic and signaling perturbations that increase cytosolic uracil levels, thereby causing wing blister formation.

Review of Options for Ammonia/Ammonium Management

Energy Technology Data Exchange (ETDEWEB)

Nash, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-05-06

This report is a review of literature supporting practical ammonia/ammonium destruction processes. Melter research supporting Hanford Low Activity Waste (LAW) glass production has shown that significant amounts of ammonia will be in the melter offgas condensate. Further work with secondary waste forms indicates the potential need to remove the ammonia, perhaps by an oxidative process. This review finds likely practical chemical methods to oxidize ammonia in aqueous solution at moderate temperatures and atmospheric pressure, using easily obtained reagents. Leading candidates include nitrite oxidation to produce nitrogen gas, various peroxide oxidative processes, and air stripping. This work reviews many other processes and provides reasoning to not consider those processes further for this application.

Surface - atmosphere exchange of ammonia over grazed pasture

NARCIS (Netherlands)

Plantaz, M.A.H.G.

1998-01-01

This thesis deals with the exchange of ammonia between the atmosphere and grazed pasture in an area of intensive livestock breeding. The term exchange is used because gaseous ammonia can be taken up (dry deposition) as well as released (emission) by this type of surface.
Ammonia exchange

Synthesis and NMR analysis of model compounds related to fucosylated chondroitin sulfates: GalNAc and Fuc(1 → 6)GalNAc derivatives.

Science.gov (United States)

Vinnitskiy, Dmitry Z; Ustyuzhanina, Nadezhda E; Dmitrenok, Andrey S; Shashkov, Alexander S; Nifantiev, Nikolay E

2017-01-13

Unsubstituted and 6-O-α-L-fucosylated propyl 2-acetamido-2-deoxy-β-D-galactopyranosides and their selectively O-sulfated (both in GalNAc and Fuc units) derivatives were synthesized as model compounds representing the fragments of fucosylated chondroitin sulfates (FCS) from sea cucumbers. Per-O-acetylated 2-deoxy-2-N-phthalimido-D-glucopyranose was used as a key precursor for the preparation of all 2-acetamido-2-deoxy-D-galactopyranoside containing products. Attempts at 6-O-glycosylation of propyl 3-O-benzoyl-2-deoxy-2-N-phthalimido-D-galactoside by 2-O-benzyl-3,4-di-O-chloracetyl-L-fucosyl trichloracetimidate in the presence of TMSOTf gave a 1:1 mixture of the corresponding α- and β-isomeric disaccharides, while the use of structurally related fucosyl bromide donor with promotion by Bu 4 NBr led to the formation of desired α-isomeric disaccharide exclusively. Selective removal of orthogonal O-protections permitted subsequent O-sulfation both at the GalNAc and Fuc units. Further removal of blocking groups yielded the target products which were systematically studied by 1 H and 13 C NMR spectroscopy in order to determine the spectral effects of O-sulfation and α-L-fucosylation needed for the development of computer assisted structural analysis of natural FCS. Copyright © 2016 Elsevier Ltd. All rights reserved.

Advanced Ceramics

International Nuclear Information System (INIS)

1989-01-01

The First Florida-Brazil Seminar on Materials and the Second State Meeting about new materials in Rio de Janeiro State show the specific technical contribution in advanced ceramic sector. The others main topics discussed for the development of the country are the advanced ceramic programs the market, the national technic-scientific capacitation, the advanced ceramic patents, etc. (C.G.C.) [pt

Eating ‘Junk-Food' Produces Rapid and Long-Lasting Increases in NAc CP-AMPA Receptors: Implications for Enhanced Cue-Induced Motivation and Food Addiction

Science.gov (United States)

Oginsky, Max F; Goforth, Paulette B; Nobile, Cameron W; Lopez-Santiago, Luis F; Ferrario, Carrie R

2016-01-01

Urges to eat are influenced by stimuli in the environment that are associated with food (food cues). Obese people are more sensitive to food cues, reporting stronger craving and consuming larger portions after food cue exposure. The nucleus accumbens (NAc) mediates cue-triggered motivational responses, and activations in the NAc triggered by food cues are stronger in people who are susceptible to obesity. This has led to the idea that alterations in NAc function similar to those underlying drug addiction may contribute to obesity, particularly in obesity-susceptible individuals. Motivational responses are mediated in part by NAc AMPA receptor (AMPAR) transmission, and recent work shows that cue-triggered motivation is enhanced in obesity-susceptible rats after ‘junk-food' diet consumption. Therefore, here we determined whether NAc AMPAR expression and function is increased by ‘junk-food' diet consumption in obesity-susceptible vs -resistant populations using both outbred and selectively bred models of susceptibility. In addition, cocaine-induced locomotor activity was used as a general ‘read out' of mesolimbic function after ‘junk-food' consumption. We found a sensitized locomotor response to cocaine in rats that gained weight on a ‘junk-food' diet, consistent with greater responsivity of mesolimbic circuits in obesity-susceptible groups. In addition, eating ‘junk-food' increased NAc calcium-permeable-AMPAR (CP-AMPAR) function only in obesity-susceptible rats. This increase occurred rapidly, persisted for weeks after ‘junk-food' consumption ceased, and preceded the development of obesity. These data are considered in light of enhanced cue-triggered motivation and striatal function in obesity-susceptible rats and the role of NAc CP-AMPARs in enhanced motivation and addiction. PMID:27383008

Characterization of ceramics used in mass ceramic industry Goianinha/RN

International Nuclear Information System (INIS)

Sales Junior, J.C.C.; Nascimento, R.M. do; Andrade, J.C.S.; Saldanha, K.M.; Dutra, R.P.S.

2011-01-01

The preparation of the the ceramic mass is one of the most important steps in the manufacture of ceramic products, since the characteristics of the raw materials used, and the proportions that they are added, directly influence the final properties of ceramic products and the operational conditions of processing. The objective of this paper is to present the results of the characterization of a ceramic mass used in the manufacture of sealing blocks by a red ceramic industry of the city of Goianinha / RN. We analyzed the chemical and mineralogical composition; thermogravimetric and differential thermal analysis; granulometric analysis; evaluation of plasticity; and determining the technological properties of specimens used in test firing at 700, 900 and 1100 ° C. The results show that the ceramic body studied has characteristics that allow use in the manufacture of sealing blocks when burned at a temperature of 900 ° C. (author)

Identification of GIG1, a GlcNAc-Induced Gene in Candida albicans Needed for Normal Sensitivity to the Chitin Synthase Inhibitor Nikkomycin Z▿§

OpenAIRE

Gunasekera, Angelo; Alvarez, Francisco J.; Douglas, Lois M.; Wang, Hong X.; Rosebrock, Adam P.; Konopka, James B.

2010-01-01

The amino sugar N-acetylglucosamine (GlcNAc) is known to be an important structural component of cells from bacteria to humans, but its roles in cell signaling are less well understood. GlcNAc induces two pathways in the human fungal pathogen Candida albicans. One activates cyclic AMP (cAMP) signaling, which stimulates the formation of hyphal cells and the expression of virulence genes, and the other pathway induces genes needed to catabolize GlcNAc. Microarray analysis of gene expression was...

O-GlcNAc modification of the coat protein of the potyvirus Plum pox virus enhances viral infection.

Science.gov (United States)

Pérez, José de Jesús; Udeshi, Namrata D; Shabanowitz, Jeffrey; Ciordia, Sergio; Juárez, Silvia; Scott, Cheryl L; Olszewski, Neil E; Hunt, Donald F; García, Juan Antonio

2013-08-01

O-GlcNAcylation is a dynamic protein modification which has been studied mainly in metazoans. We reported previously that an Arabidopsis thaliana O-GlcNAc transferase modifies at least two threonine residues of the Plum pox virus (PPV) capsid protein (CP). Now, six additional residues were shown to be involved in O-GlcNAc modification of PPV CP. CP O-GlcNAcylation was abolished in the PPV CP7-T/A mutant, in which seven threonines were mutated. PPV CP7-T/A infected Nicotiana clevelandii, Nicotiana benthamiana, and Prunus persica without noticeable defects. However, defects in infection of A. thaliana were readily apparent. In mixed infections of wild-type arabidopsis, the CP7-T/A mutant was outcompeted by wild-type virus. These results indicate that CP O-GlcNAcylation has a major role in the infection process. O-GlcNAc modification may have a role in virion assembly and/or stability as the CP of PPV CP7-T/A was more sensitive to protease digestion than that of the wild-type virus. Copyright © 2013 Elsevier Inc. All rights reserved.

Randomized, Controlled Clinical Trial of Bilayer Ceramic and Metal-Ceramic Crown Performance

Science.gov (United States)

Esquivel-Upshaw, Josephine; Rose, William; Oliveira, Erica; Yang, Mark; Clark, Arthur E.; Anusavice, Kenneth

2013-01-01

Purpose Analyzing the clinical performance of restorative materials is important, as there is an expectation that these materials and procedures will restore teeth and do no harm. The objective of this research study was to characterize the clinical performance of metal-ceramic crowns, core ceramic crowns, and core ceramic/veneer ceramic crowns based on 11 clinical criteria. Materials and Methods An IRB-approved, randomized, controlled clinical trial was conducted as a single-blind pilot study. The following three types of full crowns were fabricated: (1) metal-ceramic crown (MC) made from a Pd-Au-Ag-Sn-In alloy (Argedent 62) and a glass-ceramic veneer (IPS d.SIGN veneer); (2) non-veneered (glazed) lithium disilicate glass-ceramic crown (LDC) (IPS e.max Press core and e.max Ceram Glaze); and (3) veneered lithia disilicate glass-ceramic crown (LDC/V) with glass-ceramic veneer (IPS Empress 2 core and IPS Eris). Single-unit crowns were randomly assigned. Patients were recalled for each of 3 years and were evaluated by two calibrated clinicians. Thirty-six crowns were placed in 31 patients. A total of 12 crowns of each of the three crown types were studied. Eleven criteria were evaluated: tissue health, marginal integrity, secondary caries, proximal contact, anatomic contour, occlusion, surface texture, cracks/chips (fractures), color match, tooth sensitivity, and wear (of crowns and opposing enamel). Numerical rankings ranged from 1 to 4, with 4 being excellent, and 1 indicating a need for immediate replacement. Statistical analysis of the numerical rankings was performed using a Fisher’s exact test. Results There was no statistically significant difference between performance of the core ceramic crowns and the two veneered crowns at year 1 and year 2 (p > 0.05). All crowns were rated either as excellent or good for each of the clinical criteria; however, between years 2 and 3, gradual roughening of the occlusal surface occurred in some of the ceramic-ceramic crowns

DNA binding by the plant-specific NAC transcription factors in crystal and solution

DEFF Research Database (Denmark)

Welner, Ditte Hededam; Lindemose, Søren; Grossmann, J. Günter

2012-01-01

angle X-ray scattering on complexes with oligonucleotides, mutagenesis and (DNase I and uranyl photo-) footprinting, is combined to form a structural view of DNA-binding, and for the first time provide experimental evidence for the speculated relationship between plant-specific NAC proteins, WRKY...

Pretreatment of Biomass by Aqueous Ammonia for Bioethanol Production

Science.gov (United States)

Kim, Tae Hyun; Gupta, Rajesh; Lee, Y. Y.

The methods of pretreatment of lignocellulosic biomass using aqueous ammonia are described. The main effect of ammonia treatment of biomass is delignification without significantly affecting the carbohydrate contents. It is a very effective pretreatment method especially for substrates that have low lignin contents such as agricultural residues and herbaceous feedstock. The ammonia-based pretreatment is well suited for simultaneous saccharification and co-fermentation (SSCF) because the treated biomass retains cellulose as well as hemicellulose. It has been demonstrated that overall ethanol yield above 75% of the theoretical maximum on the basis of total carbohydrate is achievable from corn stover pretreated with aqueous ammonia by way of SSCF. There are two different types of pretreatment methods based on aqueous ammonia: (1) high severity, low contact time process (ammonia recycle percolation; ARP), (2) low severity, high treatment time process (soaking in aqueous ammonia; SAA). Both of these methods are described and discussed for their features and effectiveness.

Adjusting dental ceramics: An in vitro evaluation of the ability of various ceramic polishing kits to mimic glazed dental ceramic surface.

Science.gov (United States)

Steiner, René; Beier, Ulrike S; Heiss-Kisielewsky, Irene; Engelmeier, Robert; Dumfahrt, Herbert; Dhima, Matilda

2015-06-01

During the insertion appointment, the practitioner is often faced with the need to adjust ceramic surfaces to fit a restoration to the adjacent or opposing dentition and soft tissues. The purpose of this study was to assess the ceramic surface smoothness achieved with various commercially available ceramic polishing kits on different commonly used ceramic systems. The reliability of the cost of a polishing kit as an indicator of improved surface smoothness was assessed. A total of 350 ceramic surfaces representing 5 commonly available ceramic systems (IPS Empress Esthetic, IPS e.max Press, Cergo Kiss, Vita PM 9, Imagine PressX) were treated with 5 types of ceramic polishing systems (Cerapreshine, 94006C, Ceramiste, Optrafine, Zenostar) by following the manufacturers' guidelines. The surface roughness was measured with a profilometer (Taylor Hobson; Precision Taylor Hobson Ltd). The effects of ceramic systems and polishing kits of interest on surface roughness were analyzed by 2-way ANOVA, paired t test, and Bonferroni corrected significance level. The ceramic systems and polishing kits statistically affected surface roughness (Pceramic surface. No correlation could be established between the high cost of the polishing kit and low surface roughness. None of the commonly used ceramic polishing kits could create a surface smoother than that of glazed ceramic (Pceramic polishing kits is not recommended as a reliable indicator of better performance of ceramic polishing kits (P>.30). Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Power-to-ammonia: rethinking the role of ammonia – from a value product to a flexible energy carrier (FlexNH3)

NARCIS (Netherlands)

Bennani, Yasmina; Perl, Andras; Patil, Anish; van Someren, Christian; Heijne, Leo; van Steenis, Machiel

2016-01-01

This report focuses on the feasibility of the power-to-ammonia concept. Power-to-ammonia uses produced excess renewable electricity to electrolyze water, and then to react the obtained hydrogen with nitrogen, which is obtained through air separation, to produce ammonia. This process may be used as a

Ceramic joining

Energy Technology Data Exchange (ETDEWEB)

Loehman, R.E. [Sandia National Lab., Albuquerque, NM (United States)

1996-04-01

This paper describes the relation between reactions at ceramic-metal interfaces and the development of strong interfacial bonds in ceramic joining. Studies on a number of systems are described, including silicon nitrides, aluminium nitrides, mullite, and aluminium oxides. Joints can be weakened by stresses such as thermal expansion mismatch. Ceramic joining is used in a variety of applications such as solid oxide fuel cells.

Nitrogen metabolism and kinetics of ammonia-oxidizing archaea.

Science.gov (United States)

Martens-Habbena, Willm; Stahl, David A

2011-01-01

The discovery of ammonia-oxidizing mesophilic and thermophilic Group I archaea changed the century-old paradigm that aerobic ammonia oxidation is solely mediated by two small clades of Beta- and Gammaproteobacteria. Group I archaea are extremely diverse and ubiquitous in marine and terrestrial environments, accounting for 20-30% of the microbial plankton in the global oceans. Recent studies indicated that many of these organisms carry putative ammonia monooxygenase genes and are more abundant than ammonia-oxidizing bacteria in most natural environments suggesting a potentially significant role in the nitrogen cycle. The isolation of Nitrosopumilus maritimus strain SCM1 provided the first direct evidence that Group I archaea indeed gain energy from ammonia oxidation. To characterize the physiology of this archaeal nitrifier, we developed a respirometry setup particularly suited for activity measurements in dilute microbial cultures with extremely low oxygen uptake rates. Here, we describe the setup and review the kinetic experiments conducted with N. maritimus and other nitrifying microorganisms. These experiments demonstrated that N. maritimus is adapted to grow on ammonia concentrations found in oligotrophic open ocean environments, far below the survival threshold of ammonia-oxidizing bacteria. The described setup and experimental procedures should facilitate physiological studies on other nitrifying archaea and oligotrophic microorganisms in general. Copyright © 2011 Elsevier Inc. All rights reserved.

Industrial ceramics - Properties, forming and applications

International Nuclear Information System (INIS)

Fantozzi, Gilbert; Niepce, Jean-Claude; Bonnefont, Guillaume; Alary, J.A.; Allard, B.; Ayral, A.; Bassat, J.M.; Elissalde, C.; Maglione, M.; Beauvy, M.; Bertrand, G.; Bignon, A.; Billieres, D.; Blanc, J.J.; Blumenfeld, P.; Bonnet, J.P.; Bougoin, M.; Bourgeon, M.; Boussuge, M.; Thorel, A.; Bruzek, C.E.; Cambier, F.; Carrerot, H.; Casabonne, J.M.; Chaix, J.M.; Chevalier, J.; Chopinet, M.H.; Couque, H.; Courtois, C.; Leriche, A.; Dhaler, D.; Denape, J.; Euzen, P.; Ganne, J.P.; Gauffinet, S.; Girard, A.; Gonon, M.; Guizard, C.; Hampshire, S.; Joulin, J.P.; Julbe, A.; Ferrato, M.; Fontaine, M.L.; Lebourgeois, R.; Lopez, J.; Maquet, M.; Marinel, S.; Marrony, M.; Martin, J.F.; Mougin, J.; Pailler, R.; Pate, M.; Petitpas, E.; Pijolat, C.; Pires-Franco, P.; Poirier, C.; Poirier, J.; Pourcel, F.; Potier, A.; Tulliani, J.M.; Viricelle, J.P.; Beauger, A.

2013-01-01

After a general introduction to ceramics (definition, general properties, elaboration, applications, market data), this book address conventional ceramics (elaboration, material types), thermo-structural ceramics (oxide based ceramics, non-oxide ceramics, fields of application, functional coatings), refractory ceramics, long fibre and ceramic matrix composites, carbonaceous materials, ceramics used for filtration, catalysis and the environment, ceramics for biomedical applications, ceramics for electronics and electrical engineering (for capacitors, magnetic, piezoelectric, dielectric ceramics, ceramics for hyper-frequency resonators), electrochemical ceramics, transparent ceramics (forming and sintering), glasses, mineral binders. The last chapter addresses ceramics used in the nuclear energy sector: in nuclear fuels and fissile material, absorbing ceramics and shields, in the management of nuclear wastes, new ceramics for reactors under construction or for future nuclear energy

The origin of mouth-exhaled ammonia.

Science.gov (United States)

Chen, W; Metsälä, M; Vaittinen, O; Halonen, L

2014-09-01

It is known that the oral cavity is a production site for mouth-exhaled NH3. However, the mechanism of NH3 production in the oral cavity has been unclear. Since bacterial urease in the oral cavity has been found to produce ammonia from oral fluid urea, we hypothesize that oral fluid urea is the origin of mouth-exhaled NH3. Our results show that under certain conditions a strong correlation exists between oral fluid urea and oral fluid ammonia (NH4(+)+NH3) (rs = 0.77, p oral fluid NH3 and mouth-exhaled NH3 (rs = 0.81, p oral fluid pH. Bacterial urease catalyses the hydrolysis of oral fluid urea to ammonia (NH4(+)+NH3). Oral fluid ammonia (NH4(+)+NH3) and pH determine the concentration of oral fluid NH3, which evaporates from oral fluid into gas phase and turns to mouth-exhaled NH3.

UDP-galactose 4'-epimerase activities toward UDP-Gal and UDP-GalNAc play different roles in the development of Drosophila melanogaster.

Directory of Open Access Journals (Sweden)

Jennifer M I Daenzer

Full Text Available In both humans and Drosophila melanogaster, UDP-galactose 4'-epimerase (GALE catalyzes two distinct reactions, interconverting UDP-galactose (UDP-gal and UDP-glucose (UDP-glc in the final step of the Leloir pathway of galactose metabolism, and also interconverting UDP-N-acetylgalactosamine (UDP-galNAc and UDP-N-acetylglucosamine (UDP-glcNAc. All four of these UDP-sugars serve as vital substrates for glycosylation in metazoans. Partial loss of GALE in humans results in the spectrum disorder epimerase deficiency galactosemia; partial loss of GALE in Drosophila melanogaster also results in galactose-sensitivity, and complete loss in Drosophila is embryonic lethal. However, whether these outcomes in both humans and flies result from loss of one GALE activity, the other, or both has remained unknown. To address this question, we uncoupled the two activities in a Drosophila model, effectively replacing the endogenous dGALE with prokaryotic transgenes, one of which (Escherichia coli GALE efficiently interconverts only UDP-gal/UDP-glc, and the other of which (Plesiomonas shigelloides wbgU efficiently interconverts only UDP-galNAc/UDP-glcNAc. Our results demonstrate that both UDP-gal and UDP-galNAc activities of dGALE are required for Drosophila survival, although distinct roles for each activity can be seen in specific windows of developmental time or in response to a galactose challenge. By extension, these data also suggest that both activities might play distinct and essential roles in humans.

15N-enrichments of ammonia and glutamine in blood after infusion of 15N-ammonia in chickens fed low or high protein diet

International Nuclear Information System (INIS)

Karasawa, Yutaka; Koh, Katsuki

1985-01-01

In this experment, the blood ammonia and glutamine amide came from infused ammonia were determined when N-15 labeled ammonium acetate was intraportally infused into the chickens fed 5 or 20 % protein diet. The data obtained indicated that the infused ammonia was taken into blood glutamine amide, and also accumulated in blood as it is, in both dietary groups. 10 to 12 months old White Leghorn male birds were used. The experimental diet was fed once a day for 5 days to the birds weighting about 1.2 kg by 35 g per kg body weight. The experimental diet was consumed within 40 min in all cases. Cardiac and portal catheterization were performed for blood collection and ammonia infusion, respectively. After finishing the infusion, blood samples were taken to analyze the ammonia and glutamine contents and their N-15 enrichment. Statistical difference was not observed in the appearance of N-15 in ammonia and glutamine amide between two dietary groups. The N-15 enrichment in blood ammonia and the amide of plasma glutamine, and the calculated exogenous nitrogen in the ammonia and glutamine amide tended to be more in the 5 % protein diet group than the other. (Kako, I.)

Growth of ammonia-oxidizing archaea and bacteria in cattle manure compost under various temperatures and ammonia concentrations.

Science.gov (United States)

Oishi, Ryu; Tada, Chika; Asano, Ryoki; Yamamoto, Nozomi; Suyama, Yoshihisa; Nakai, Yutaka

2012-05-01

A recent study showed that ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) coexist in the process of cattle manure composting. To investigate their physiological characteristics, liquid cultures seeded with fermenting cattle manure compost were incubated at various temperatures (37°C, 46°C, or 60°C) and ammonium concentrations (0.5, 1, 4, or 10 mM NH (4) (+) -N). The growth rates of the AOB and AOA were monitored using real-time polymerase chain reaction analysis targeting the bacterial and archaeal ammonia monooxygenase subunit A genes. AOB grew at 37°C and 4 or 10 mM NH (4) (+) -N, whereas AOA grew at 46°C and 10 mM NH (4) (+) -N. Incubation with allylthiourea indicated that the AOB and AOA grew by oxidizing ammonia. Denaturing gradient gel electrophoresis and subsequent sequencing analyses revealed that a bacterium related to Nitrosomonas halophila and an archaeon related to Candidatus Nitrososphaera gargensis were the predominant AOB and AOA, respectively, in the seed compost and in cultures after incubation. This is the first report to demonstrate that the predominant AOA in cattle manure compost can grow and can probably oxidize ammonia under moderately thermophilic conditions.

Ammonia as a respiratory gas in water and air-breathing fishes.

Science.gov (United States)

Randall, David J; Ip, Yuen K

2006-11-01

Ammonia is produced in the liver and excreted as NH(3) by diffusion across the gills. Elevated ammonia results in an increase in gill ventilation, perhaps via stimulation of gill oxygen chemo-receptors. Acidification of the water around the fish by carbon dioxide and acid excretion enhances ammonia excretion and constitutes "environmental ammonia detoxification". Fish have difficulties in excreting ammonia in alkaline water or high concentrations of environmental ammonia, or when out of water. The mudskipper, Periphthalmodon schlosseri, is capable of active NH(4)(+) transport, maintaining low internal levels of ammonia. To prevent a back flux of NH(3), these air-breathing fish can increase gill acid excretion and reduce the membrane NH(3) permeability by modifying the phospholipid and cholesterol compositions of their skin. Several air-breathing fish species can excrete ammonia into air through NH(3) volatilization. Some fish detoxify ammonia to glutamine or urea. The brains of some fish can tolerate much higher levels of ammonia than other animals. Studies of these fish may offer insights into the nature of ammonia toxicity in general.

Tribology of ceramics: Report of the Committee on Tribology of Ceramics

Science.gov (United States)

1988-01-01

The current state of knowledge of ceramic surface structures, composition, and reactivity is reviewed. The tribological requirements of advanced mechanical systems now being deployed (in particular, heat engines) exceed the capabilities of traditional metallic-based materials because of the high temperatures encountered. Advanced ceramic materials for such applications are receiving intense scrutiny, but there is a lack of understanding of the properties and behavior of ceramic surfaces and the influence of processing on the properties of ceramics is described. The adequacy of models, ranging form atomic to macro, to describe and to predict ceramic friction and wear are discussed, as well as what is known about lubrication at elevated temperatures. From this analysis, recommendations are made for coordination, research, and development that will lead to better performance of ceramic materials in tribological systems.

Ammonia Sensor Using Wavelength Modulation Spectroscopy

KAUST Repository

Farooq, Aamir; Owen, Kyle

2015-01-01

An ammonia sensor can include a laser detector configured to provide stable sample readings. The sensor can implement a method including processing the recorded intensity of the laser beam to determine a first harmonic component and a second harmonic component and the amount of ammonia in the sample.

Ammonia Sensor Using Wavelength Modulation Spectroscopy

KAUST Repository

Farooq, Aamir

2015-09-01

An ammonia sensor can include a laser detector configured to provide stable sample readings. The sensor can implement a method including processing the recorded intensity of the laser beam to determine a first harmonic component and a second harmonic component and the amount of ammonia in the sample.

Atmospheric behaviour of ammonia and ammonium

NARCIS (Netherlands)

Asman, W.A.H.

1987-01-01

1.4.1 Scope of this thesis

A few models for ammonia and ammonium exist. Russell et al. (1983) made a multi-layer Lagrangian transport model describing the transport and formation of ammonium nitrate aerosol for California. They did not take reactions of ammonia and sulphuric acid

Distorting the ceramic familiar: materiality and non-ceramic intervention, Conference, Keramik Museum, Germany

OpenAIRE

Livingstone, Andrew

2009-01-01

Invited conference speaker, Westerwald Keramik Museum, August 2009. Paper title: Distorting the ceramic familiar: materiality and non-ceramic intervention.\\ud \\ud This paper will examine the integration of non-ceramic media into the discourse of ceramics.

46 CFR 151.50-32 - Ammonia, anhydrous.

Science.gov (United States)

2010-10-01

... enclosed anhydrous ammonia tanks complies with the following chemical and physical properties: (1) Boiling... requirements of § 151.50-30 for compressed gases are also applicable to the shipment of anhydrous ammonia...

Formulation and synthesis by melting process of titanate enriched glass-ceramics and ceramics

International Nuclear Information System (INIS)

Advocat, T.; Fillet, C.; Lacombe, J.; Bonnetier, A.; McGlinn, P.

1999-01-01

The main objective of this work is to provide containment for the separated radionuclides in stable oxide phases with proven resistance to leaching and irradiation damage and in consequence to obtain a glass ceramic or a ceramic material using a vitrification process. Sphene glass ceramic, zirconolite glass ceramic and zirconolite enriched ceramic have been fabricated and characterized by XRD, SEM/EDX and DTA

The barley HvNAC6 transcription factor affects ABA accumulation and promotes basal resistance against powdery mildew

DEFF Research Database (Denmark)

Chen, Yan-Jun; Perera, Venura; Wagner, Michael

2013-01-01

Barley HvNAC6 is a member of the plant-specific NAC (NAM, ATAF1,2, CUC2) transcription factor family and we have shown previously that it acts as a positive regulator of basal resistance in barley against the biotrophic pathogen Blumeria graminis f. sp. hordei (Bgh). In this study, we use a trans...

Exhaust gas sensors for NO{sub x} storage catalysts and ammonia SCR systems; Abgassensoren fuer NO{sub x}-Speicherkatalysatoren und Ammoniak-SCR-Systeme

Energy Technology Data Exchange (ETDEWEB)

Moos, R. [Bayreuth Univ. (DE). Bayreuth Engine Research Center (BERC)

2008-07-01

Measuring of the air-to-fuel ratio and/or the exhaust gas oxygen content with the help of an exhaust gas sensor has been established thirty years ago. Whereas the original thimble type lambda probe, which is still shown today in textbooks, is a product of classical ceramic technology, newer sensors are manufactured in planar multilayer technology stemming from electronic technology. This is the basis for additional functionalities like NO{sub x} or ammonia sensitivities. Due to increasing requirements for OBD, the sensor of the future might be a multifunctional device which allows for measuring application specific components as well as lambda in a wide range. From a technical standpoint, it would even today be feasible to manufacture an integrated exhaust gas sensor that can measure ammonia, NO{sub x}, and lambda at the same time. Whether the direct catalyst status diagnosis will become ripe for serial application does not depends only on technical questions and cost considerations but also on the issue whether one is willing to establish a completely novel way of catalyst detection in the exhaust pipe. (orig.)

Comparison of ammonia emissions determined using different sampling methods

Science.gov (United States)

Dynamic, flow-through flux chambers are sometimes used to estimate ammonia emissions from livestock operations; however, ammonia emissions from the surfaces are affected by many factors which can be affected by the chamber. Ammonia emissions estimated using environmental flow-through chambers may be...

Scale up issues involved with the ceramic waste form: ceramic-container interactions and ceramic cracking quantification

International Nuclear Information System (INIS)

Bateman, K. J.; DiSanto, T.; Goff, K. M.; Johnson, S. G.; O'Holleran, T.; Riley, W. P. Jr.

1999-01-01

Argonne National Laboratory is developing a process for the conditioning of spent nuclear fuel to prepare the material for final disposal. Two waste streams will result from the treatment process, a stainless steel based form and a ceramic based form. The ceramic waste form will be enclosed in a stainless steel container. In order to assess the performance of the ceramic waste form in a repository two factors must be examined, the surface area increases caused by waste form cracking and any ceramic/canister interactions that may release toxic material. The results indicate that the surface area increases are less than the High Level Waste glass and any toxic releases are below regulatory limits

Study on an integrated process combining ozonation with ceramic ultra-filtration for decentralized supply of drinking water.

Science.gov (United States)

Zhu, Jia; Fan, Xiao J; Tao, Yi; Wei, De Q; Zhang, Xi H

2014-09-19

An integrated process was specifically developed for the decentralized supply of drinking water from micro-polluted surface water in the rural areas of China. The treatment process combined ozonation with ceramic ultra-filtration (UF), coagulation for pre-treatment and granular activated carbon filtration. A flat-sheet ceramic membrane was used with a cut-off of 60 nm and the measurement of 254 mm (length) × 240 mm (width) × 6 mm (thickness). Ozonation and ceramic UF was set up whthin one reactor. The experimental results showed that the removal efficiencies of the dissolved organic carbon (DOC) and the formation potential of trihalomethanes (THMs), haloacetic acids (HAAs) and ammonia were 80%, 76%, 70% and 90%, respectively; that the turbidity of the product water was below 0.2 NTU and the particle count number (particles larger than 2 μm) was less than 50 counts per mL. The result also showed that all the pathogenic microorganisms were retained by the ceramic and that UF. Ozonation played a critical role in the control of membrane fouling and the removal of contaminants. Exactly, the membrane fouling can be controlled in situ with 3 mg L(-1) ozone at the permeate flux of 80 L m(-2) h(-1), yet the required dosage of ozone was dependent on the quality of the raw water. Therefore, this study is able to provide a highly compacted system for decentralized supply of high-quality drinking water in terms of both chemical and microbiological safety for the rural areas in China.

46 CFR 98.25-5 - How anhydrous ammonia may be carried.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false How anhydrous ammonia may be carried. 98.25-5 Section 98... Anhydrous Ammonia in Bulk § 98.25-5 How anhydrous ammonia may be carried. (a) Anhydrous ammonia shall be..., except as otherwise provided in paragraph (b) of this section. (b) When anhydrous ammonia is to be...

Characterization techniques to predict mechanical behaviour of green ceramic bodies fabricated by ceramic microstereolithography

Science.gov (United States)

Adake, Chandrashekhar V.; Bhargava, Parag; Gandhi, Prasanna

2018-02-01

Ceramic microstereolithography (CMSL) has emerged as solid free form (SFF) fabrication technology in which complex ceramic parts are fabricated from ceramic suspensions which are formulated by dispersing ceramic particles in UV curable resins. Ceramic parts are fabricated by exposing ceramic suspension to computer controlled UV light which polymerizes resin to polymer and this polymer forms rigid network around ceramic particles. A 3-dimensional part is created by piling cured layers one over the other. These ceramic parts are used to build microelectromechanical (MEMS) devices after thermal treatment. In many cases green ceramic parts can be directly utilized to build MEMS devices. Hence characterization of these parts is essential in terms of their mechanical behaviour prior to their use in MEMS devices. Mechanical behaviour of these green ceramic parts depends on cross link density which in turn depends on chemical structure of monomer, concentrations of photoinitiator and UV energy dose. Mechanical behaviour can be determined with the aid of nanoindentation. And extent of crosslinking can be verified with the aid of DSC. FTIR characterization is used to analyse (-C=C-) double bond conversion. This paper explains characterization tools to predict the mechanical behaviour of green ceramic bodies fabricated in CMSL

Fracture-dissociation of ceramic liner.

Science.gov (United States)

Hwang, Sung Kwan; Oh, Jin-Rok; Her, Man Seung; Shim, Young Jun; Cho, Tae Yeun; Kwon, Sung Min

2008-08-01

The use of BIOLOX delta ceramic (CeramTec AG, Plochingen, Germany) has been increasing. This ceramic prevents cracking by restraining the phase transformation due to the insertion of nano-sized, yttria-stabilized tetragonal zirconia into the alumina matrix. This restrains the progress of cracking through the formation of platelet-like crystal or whiskers due to the addition of an oxide additive. We observed a case of BIOLOX delta ceramic liner (CeramTec AG) rim fracture 4 months postoperatively. Radiographs showed that the ceramic liner was subluxated from the acetabular cup. Scratches on the acetabular cup and femoral neck were seen, and the fracture was visible on the rim of the liner. Under electron microscope, metal particle coatings from the ceramic liner were identified. The ceramic liner, fracture fragments, and adjacent tissues were removed and replaced with a ceramic liner and femoral head of the same size and design. We believe the mechanism of the fracture-dissociation of the ceramic liner in this case is similar to a case of separation of the ceramic liner from the polyethylene shell in a sandwich-type ceramic-ceramic joint. To prevent ceramic liner fracture-dissociation, the diameter of the femoral neck needs to be decreased in a new design, while the diameter of the femoral head needs to be increased to ensure an increase in range of motion.

Ammonia-water Rankine cycle

International Nuclear Information System (INIS)

Bo Hanliang; Ma Changwen; Wu Shaorong

1997-01-01

On characteristics of heating source and cooling source in nuclear heating reactor cooperation, the authors advance a new kind of power cycle in which a multicomponent mixture as the work fluid, ammonia-water Rankine cycle, describe its running principle, and compare it with steam Rankine cycle in the same situation. The result is that: the new kind of power cycle, ammonia-water Rankine cycle has higher electricity efficiency; it suits for the situation of heating source and cooling source which offered by nuclear heating reactor cooperation. For low temperature heating source, it maybe has a widely application

Effect of competing ions and causticization on the ammonia adsorption by a novel poly ligand exchanger (PLE) ammonia adsorption reagent.

Science.gov (United States)

Chen, Quanzhou; Zhou, Kanggen; Hu, Yuanjuan; Liu, Fang; Wang, Aihe

2017-03-01

In this paper, a poly ligand exchanger, Cu(II)-loaded chelating resin named ammonia adsorption reagent (AMAR), bearing the functional group of weak iminodiacetate acid, was prepared to efficiently remove ammonia from solutions. Batch adsorption equilibrium experiments were conducted under a range of conditions. The effects of pH on the removal of ammonia by AMAR were investigated at 25 °C. The copper loaded on the resin forms a complex with NH 3 in solution under alkaline condition. The effect of alkaline dosage (AD) on the ammonia adsorption was investigated. The maximum breakthrough bed volumes were obtained when the AD was set as 0.75 mmol OH - /mL. The higher AD did not guarantee the better ammonia removal efficiency due to the forming of Cu(OH) 2 precipitate between OH - in solutions and Cu(II) on the resin. The effect of competing ions on the adsorption breakthrough curve of virgin AMAR and causticized AMAR was also investigated. The results demonstrated that the existence of competing ions had a negative impact on the adsorption capacity for both virgin AMAR and causticized AMAR. After causticization, the AMAR was more resistant to the competing ions comparing with virgin AMAR. The bivalent Ca 2+ affects the ammonia adsorption more than does the monovalent Na + .

Lipopolysaccharide impairs hepatocyte ureagenesis from ammonia: involvement of mitochondrial aquaporin-8.

Science.gov (United States)

Soria, Leandro R; Marrone, Julieta; Molinas, Sara M; Lehmann, Guillermo L; Calamita, Giuseppe; Marinelli, Raúl A

2014-05-02

We recently reported that hepatocyte mitochondrial aquaporin-8 (mtAQP8) channels facilitate the uptake of ammonia and its metabolism into urea. Here we studied the effect of bacterial lipopolysaccharides (LPS) on ammonia-derived ureagenesis. In LPS-treated rats, hepatic mtAQP8 protein expression and diffusional ammonia permeability (measured utilizing ammonia analogues) of liver inner mitochondrial membranes were downregulated. NMR studies using 15N-labeled ammonia indicated that basal and glucagon-induced ureagenesis from ammonia were significantly reduced in hepatocytes from LPS-treated rats. Our data suggest that hepatocyte mtAQP8-mediated ammonia removal via ureagenesis is impaired by LPS, a mechanism potentially relevant to the molecular pathogenesis of defective hepatic ammonia detoxification in sepsis. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Simultaneous removal of ammonia and N-nitrosamine precursors from high ammonia water by zeolite and powdered activated carbon.

Science.gov (United States)

Xue, Runmiao; Donovan, Ariel; Zhang, Haiting; Ma, Yinfa; Adams, Craig; Yang, John; Hua, Bin; Inniss, Enos; Eichholz, Todd; Shi, Honglan

2018-02-01

When adding sufficient chlorine to achieve breakpoint chlorination to source water containing high concentration of ammonia during drinking water treatment, high concentrations of disinfection by-products (DBPs) may form. If N-nitrosamine precursors are present, highly toxic N-nitrosamines, primarily N-nitrosodimethylamine (NDMA), may also form. Removing their precursors before disinfection should be a more effective way to minimize these DBPs formation. In this study, zeolites and activated carbon were examined for ammonia and N-nitrosamine precursor removal when incorporated into drinking water treatment processes. The test results indicate that Mordenite zeolite can remove ammonia and five of seven N-nitrosamine precursors efficiently by single step adsorption test. The practical applicability was evaluated by simulation of typical drinking water treatment processes using six-gang stirring system. The Mordenite zeolite was applied at the steps of lime softening, alum coagulation, and alum coagulation with powdered activated carbon (PAC) sorption. While the lime softening process resulted in poor zeolite performance, alum coagulation did not impact ammonia and N-nitrosamine precursor removal. During alum coagulation, more than 67% ammonia and 70%-100% N-nitrosamine precursors were removed by Mordenite zeolite (except 3-(dimethylaminomethyl)indole (DMAI) and 4-dimethylaminoantipyrine (DMAP)). PAC effectively removed DMAI and DMAP when added during alum coagulation. A combination of the zeolite and PAC selected efficiently removed ammonia and all tested seven N-nitrosamine precursors (dimethylamine (DMA), ethylmethylamine (EMA), diethylamine (DEA), dipropylamine (DPA), trimethylamine (TMA), DMAP, and DMAI) during the alum coagulation process. Copyright © 2017. Published by Elsevier B.V.

What every surgeon should know about Ceramic-on-Ceramic bearings in young patients

OpenAIRE

Hernigou, Philippe; Roubineau, Fran?ois; Bouthors, Charlie; Flouzat-Lachaniette, Charles-Henri

2016-01-01

Based on the exceptional tribological behaviour and on the relatively low biological activity of ceramic particles, Ceramic-on-Ceramic (CoC) total hip arthroplasty (THA) presents significant advantages CoC bearings decrease wear and osteolysis, the cumulative long-term risk of dislocation, muscle atrophy, and head-neck taper corrosion. However, there are still concerns regarding the best technique for implantation of ceramic hips to avoid fracture, squeaking, and revision of ceramic hips with...

Ammonia pollution characteristics of centralized drinking water sources in China.

Science.gov (United States)

Fu, Qing; Zheng, Binghui; Zhao, Xingru; Wang, Lijing; Liu, Changming

2012-01-01

The characteristics of ammonia in drinking water sources in China were evaluated during 2005-2009. The spatial distribution and seasonal changes of ammonia in different types of drinking water sources of 22 provinces, 5 autonomous regions and 4 municipalities were investigated. The levels of ammonia in drinking water sources follow the order of river > lake/reservoir > groundwater. The levels of ammonia concentration in river sources gradually decreased from 2005 to 2008, while no obvious change was observed in the lakes/reservoirs and groundwater drinking water sources. The proportion of the type of drinking water sources is different in different regions. In river drinking water sources, the ammonia level was varied in different regions and changed seasonally. The highest value and wide range of annual ammonia was found in South East region, while the lowest value was found in Southwest region. In lake/reservoir drinking water sources, the ammonia levels were not varied obviously in different regions. In underground drinking water sources, the ammonia levels were varied obviously in different regions due to the geological permeability and the natural features of regions. In the drinking water sources with higher ammonia levels, there are enterprises and wastewater drainages in the protected areas of the drinking water sources.

Ammonia and nitrite oxidation in the Eastern Tropical North Pacific

Science.gov (United States)

Peng, Xuefeng; Fuchsman, Clara A.; Jayakumar, Amal; Oleynik, Sergey; Martens-Habbena, Willm; Devol, Allan H.; Ward, Bess B.

2015-12-01

Nitrification plays a key role in the marine nitrogen (N) cycle, including in oceanic oxygen minimum zones (OMZs), which are hot spots for denitrification and anaerobic ammonia oxidation (anammox). Recent evidence suggests that nitrification links the source (remineralized organic matter) and sink (denitrification and anammox) of fixed N directly in the steep oxycline in the OMZs. We performed shipboard incubations with 15N tracers to characterize the depth distribution of nitrification in the Eastern Tropical North Pacific (ETNP). Additional experiments were conducted to investigate photoinhibition. Allylthiourea (ATU) was used to distinguish the contribution of archaeal and bacterial ammonia oxidation. The abundance of archaeal and β-proteobacterial ammonia monooxygenase gene subunit A (amoA) was determined by quantitative polymerase chain reaction. The rates of ammonia and nitrite oxidation showed distinct subsurface maxima, with the latter slightly deeper than the former. The ammonia oxidation maximum coincided with the primary nitrite concentration maximum, archaeal amoA gene maximum, and the subsurface nitrous oxide maximum. Negligible rates of ammonia oxidation were found at anoxic depths, where high rates of nitrite oxidation were measured. Archaeal amoA gene abundance was generally 1 to 2 orders of magnitude higher than bacterial amoA gene abundance, and inhibition of ammonia-oxidizing bacteria with 10 μM ATU did not affect ammonia oxidation rates, indicating the dominance of archaea in ammonia oxidation. These results depict highly dynamic activities of ammonia and nitrite oxidation in the oxycline of the ETNP OMZ.

Ammonia causes decreased brain monoamines in fathead minnows (Pimephales promelas)

Science.gov (United States)

Ronan, Patrick J.; Gaikowski, Mark P.; Hamilton, Steven J.; Buhl, Kevin J.; Summers, Cliff H.

2007-01-01

Hyperammonemia, arising from variety of disorders, leads to severe neurological dysfunction. The mechanisms of ammonia toxicity in brain are not completely understood. This study investigated the effects of ammonia on monoaminergic systems in brains of fathead minnows (Pimephales promelas). Fish serve as a good model system to investigate hyperammonemic effects on brain function since no liver manipulations are necessary to increase endogenous ammonia concentrations. Using high performance liquid chromatography with electrochemical detection, monoamines and some associated metabolites were measured from whole brain homogenate. Adult males were exposed for 48 h to six different concentrations of ammonia (0.01–2.36 mg/l unionized) which bracketed the 96-h LC50 for this species. Ammonia concentration-dependent decreases were found for the catecholamines (norepinephrine and dopamine) and the indoleamine serotonin (5-HT). After an initial increase in the 5-HT precursor 5-hydroxytryptophan it too decreased with increasing ammonia concentrations. There were also significant increases in the 5-HIAA/5-HT and DOPAC/DA ratios, often used as measures of turnover. There were no changes in epinephrine (Epi) or monoamine catabolites (DOPAC, 5-HIAA) at any ammonia concentrations tested. Results suggest that ammonia causes decreased synthesis while also causing increased release and degradation. Increased release may underlie behavioral reactions to ammonia exposure in fish. This study adds weight to a growing body of evidence demonstrating that ammonia leads to dysfunctional monoaminergic systems in brain which may underlie neurological symptoms associated with human disorders such as hepatic encephalopathy.

Ceramic Parts for Turbines

Science.gov (United States)

Jones, R. D.; Carpenter, Harry W.; Tellier, Jim; Rollins, Clark; Stormo, Jerry

1987-01-01

Abilities of ceramics to serve as turbine blades, stator vanes, and other elements in hot-gas flow of rocket engines discussed in report. Ceramics prime candidates, because of resistance to heat, low density, and tolerance of hostile environments. Ceramics considered in report are silicon nitride, silicon carbide, and new generation of such ceramic composites as transformation-toughened zirconia and alumina and particulate- or whisker-reinforced matrices. Report predicts properly designed ceramic components viable in advanced high-temperature rocket engines and recommends future work.

Nitrite as a stimulus for ammonia-starved Nitrosomonas europaea

NARCIS (Netherlands)

Laanbroek, H.J.; Bär-Gilissen, M.J.; Hoogveld, H.L.

2002-01-01

Ammonia-starved cells of Nitrosomonas europaea are able to preserve a high level of ammonia-oxidizing activity in the absence of ammonium. However, when the nitrite-oxidizing cells that form part of the natural nitrifying community do not keep pace with the ammonia-oxidizing cells, nitrite

Protein intrinsic disorder in Arabidopsis NAC transcription factors

DEFF Research Database (Denmark)

O'Shea, Charlotte; Jensen, Mikael Kryger; Stender, Emil G.P.

2015-01-01

of differences in binding mechanisms. Although substitution of both hydrophobic and acidic residues of the ANAC046 MoRF region abolished binding, substitution of other residues, even with α-helix-breaking proline, was less disruptive. Together, the biophysical analyses suggest that RCD1-ANAC046 complex formation......Protein ID (intrinsic disorder) plays a significant, yet relatively unexplored role in transcription factors (TFs). In the present paper, analysis of the transcription regulatory domains (TRDs) of six phylogenetically representative, plant-specific NAC [no apical meristem, ATAF (Arabidopsis...

Ammonia-based feedforward and feedback aeration control in activated sludge processes.

Science.gov (United States)

Rieger, Leiv; Jones, Richard M; Dold, Peter L; Bott, Charles B

2014-01-01

Aeration control at wastewater treatment plants based on ammonia as the controlled variable is applied for one of two reasons: (1) to reduce aeration costs, or (2) to reduce peaks in effluent ammonia. Aeration limitation has proven to result in significant energy savings, may reduce external carbon addition, and can improve denitrification and biological phosphorus (bio-P) performance. Ammonia control for limiting aeration has been based mainly on feedback control to constrain complete nitrification by maintaining approximately one to two milligrams of nitrogen per liter of ammonia in the effluent. Increased attention has been given to feedforward ammonia control, where aeration control is based on monitoring influent ammonia load. Typically, the intent is to anticipate the impact of sudden load changes, and thereby reduce effluent ammonia peaks. This paper evaluates the fundamentals of ammonia control with a primary focus on feedforward control concepts. A case study discussion is presented that reviews different ammonia-based control approaches. In most instances, feedback control meets the objectives for both aeration limitation and containment of effluent ammonia peaks. Feedforward control, applied specifically for switching aeration on or off in swing zones, can be beneficial when the plant encounters particularly unusual influent disturbances.

ORTHO-TO-PARA ABUNDANCE RATIO (OPR) OF AMMONIA IN 15 COMETS: OPRs OF AMMONIA VERSUS 14N/15N RATIOS IN CN

International Nuclear Information System (INIS)

Shinnaka, Yoshiharu; Kawakita, Hideyo; Kobayashi, Hitomi; Jehin, Emmanuel; Manfroid, Jean; Hutsemekers, Damien; Arpigny, Claude

2011-01-01

The ortho-to-para abundance ratio (OPR) of cometary molecules is considered to be one of the primordial characteristics of cometary ices. We present OPRs of ammonia (NH 3 ) in 15 comets based on optical high-dispersion spectroscopic observations of NH 2 , which is a photodissociation product of ammonia in the gaseous coma. The observations were mainly carried out with the VLT/UVES. The OPR of ammonia is estimated from the OPR of NH 2 based on the observations of the NH 2 (0, 9, 0) vibronic band. The absorption lines by the telluric atmosphere are corrected and the cometary C 2 emission lines blended with NH 2 lines are removed in our analysis. The ammonia OPRs show a cluster between 1.1 and 1.2 (this corresponds to a nuclear spin temperature of ∼30 K) for all comets in our sample except for 73P/Schwassmann-Wachmann 3 (73P/SW3). Comet 73P/SW3 (both B- and C-fragments) shows the OPR of ammonia consistent with nuclear spin statistical weight ratio (1.0) that indicates a high-temperature limit as nuclear spin temperature. We compared the ammonia OPRs with other properties ( 14 N/ 15 N ratios in CN, D/H ratios of water, and mixing ratios of volatiles). Comet 73P/SW3 is clearly different from the other comets in the plot of ammonia OPRs versus 14 N/ 15 N ratios in CN. The ammonia OPRs of 1.0 and lower 15 N-fractionation of CN in comet 73P/SW3 imply that icy materials in this comet formed under warmer conditions than other comets. Comets may be classified into two groups in the plot of ammonia OPRs against 14 N/ 15 N ratios in CN.

Excretory nitrogen metabolism and defence against ammonia toxicity in air-breathing fishes.

Science.gov (United States)

Chew, S F; Ip, Y K

2014-03-01

With the development of air-breathing capabilities, some fishes can emerge from water, make excursions onto land or even burrow into mud during droughts. Air-breathing fishes have modified gill morphology and morphometry and accessory breathing organs, which would tend to reduce branchial ammonia excretion. As ammonia is toxic, air-breathing fishes, especially amphibious ones, are equipped with various strategies to ameliorate ammonia toxicity during emersion or ammonia exposure. These strategies can be categorized into (1) enhancement of ammonia excretion and reduction of ammonia entry, (2) conversion of ammonia to a less toxic product for accumulation and subsequent excretion, (3) reduction of ammonia production and avoidance of ammonia accumulation and (4) tolerance of ammonia at cellular and tissue levels. Active ammonia excretion, operating in conjunction with lowering of ambient pH and reduction in branchial and cutaneous NH₃ permeability, is theoretically the most effective strategy to maintain low internal ammonia concentrations. NH₃ volatilization involves the alkalization of certain epithelial surfaces and requires mechanisms to prevent NH₃ back flux. Urea synthesis is an energy-intensive process and hence uncommon among air-breathing teleosts. Aestivating African lungfishes detoxify ammonia to urea and the accumulated urea is excreted following arousal. Reduction in ammonia production is achieved in some air-breathing fishes through suppression of amino acid catabolism and proteolysis, or through partial amino acid catabolism leading to alanine formation. Others can slow down ammonia accumulation through increased glutamine synthesis in the liver and muscle. Yet, some others develop high tolerance of ammonia at cellular and tissue levels, including tissues in the brain. In summary, the responses of air-breathing fishes to ameliorate ammonia toxicity are many and varied, determined by the behaviour of the species and the nature of the environment in

Ammonia in the environment: From ancient times to the present

International Nuclear Information System (INIS)

Sutton, Mark A.; Erisman, Jan Willem; Dentener, Frank; Moeller, Detlev

2008-01-01

Recent research on atmospheric ammonia has made good progress in quantifying sources/sinks and environmental impacts. This paper reviews the achievements and places them in their historical context. It considers the role of ammonia in the development of agricultural science and air chemistry, showing how these arose out of foundations in 18th century chemistry and medieval alchemy, and then identifies the original environmental sources from which the ancients obtained ammonia. Ammonia is revealed as a compound of key human interest through the centuries, with a central role played by sal ammoniac in alchemy and the emergence of modern science. The review highlights how recent environmental research has emphasized volatilization sources of ammonia. Conversely, the historical records emphasize the role of high-temperature sources, including dung burning, coal burning, naturally burning coal seams and volcanoes. Present estimates of ammonia emissions from these sources are based on few measurements, which should be a future priority. - Past ammonia applications reveal new emphases in biospheric transformations

Transcript Profiling Identifies NAC-Domain Genes Involved in Regulating Wall Ingrowth Deposition in Phloem Parenchyma Transfer Cells of Arabidopsis thaliana

Directory of Open Access Journals (Sweden)

Yuzhou Wu

2018-03-01

Full Text Available Transfer cells (TCs play important roles in facilitating enhanced rates of nutrient transport at key apoplasmic/symplasmic junctions along the nutrient acquisition and transport pathways in plants. TCs achieve this capacity by developing elaborate wall ingrowth networks which serve to increase plasma membrane surface area thus increasing the cell's surface area-to-volume ratio to achieve increased flux of nutrients across the plasma membrane. Phloem parenchyma (PP cells of Arabidopsis leaf veins trans-differentiate to become PP TCs which likely function in a two-step phloem loading mechanism by facilitating unloading of photoassimilates into the apoplasm for subsequent energy-dependent uptake into the sieve element/companion cell (SE/CC complex. We are using PP TCs in Arabidopsis as a genetic model to identify transcription factors involved in coordinating deposition of the wall ingrowth network. Confocal imaging of pseudo-Schiff propidium iodide-stained tissue revealed different profiles of temporal development of wall ingrowth deposition across maturing cotyledons and juvenile leaves, and a basipetal gradient of deposition across mature adult leaves. RNA-Seq analysis was undertaken to identify differentially expressed genes common to these three different profiles of wall ingrowth deposition. This analysis identified 68 transcription factors up-regulated two-fold or more in at least two of the three experimental comparisons, with six of these transcription factors belonging to Clade III of the NAC-domain family. Phenotypic analysis of these NAC genes using insertional mutants revealed significant reductions in levels of wall ingrowth deposition, particularly in a double mutant of NAC056 and NAC018, as well as compromised sucrose-dependent root growth, indicating impaired capacity for phloem loading. Collectively, these results support the proposition that Clade III members of the NAC-domain family in Arabidopsis play important roles in

Ammonia Induces Autophagy through Dopamine Receptor D3 and MTOR

Science.gov (United States)

Li, Zhiyuan; Ji, Xinmiao; Wang, Wenchao; Liu, Juanjuan; Liang, Xiaofei; Wu, Hong; Liu, Jing; Eggert, Ulrike S.; Liu, Qingsong

2016-01-01

Hyperammonemia is frequently seen in tumor microenvironments as well as in liver diseases where it can lead to severe brain damage or death. Ammonia induces autophagy, a mechanism that tumor cells may use to protect themselves from external stresses. However, how cells sense ammonia has been unclear. Here we show that culture medium alone containing Glutamine can generate milimolar of ammonia at 37 degrees in the absence of cells. In addition, we reveal that ammonia acts through the G protein-coupled receptor DRD3 (Dopamine receptor D3) to induce autophagy. At the same time, ammonia induces DRD3 degradation, which involves PIK3C3/VPS34-dependent pathways. Ammonia inhibits MTOR (mechanistic target of Rapamycin) activity and localization in cells, which is mediated by DRD3. Therefore, ammonia has dual roles in autophagy: one to induce autophagy through DRD3 and MTOR, the other to increase autophagosomal pH to inhibit autophagic flux. Our study not only adds a new sensing and output pathway for DRD3 that bridges ammonia sensing and autophagy induction, but also provides potential mechanisms for the clinical consequences of hyperammonemia in brain damage, neurodegenerative diseases and tumors. PMID:27077655

Closing CO2 Loop in Biogas Production: Recycling Ammonia As Fertilizer.

Science.gov (United States)

He, Qingyao; Yu, Ge; Tu, Te; Yan, Shuiping; Zhang, Yanlin; Zhao, Shuaifei

2017-08-01

We propose and demonstrate a novel system for simultaneous ammonia recovery, carbon capture, biogas upgrading, and fertilizer production in biogas production. Biogas slurry pretreatment (adjusting the solution pH, turbidity, and chemical oxygen demand) plays an important role in the system as it significantly affects the performance of ammonia recovery. Vacuum membrane distillation is used to recover ammonia from biogas slurry at various conditions. The ammonia removal efficiency in vacuum membrane distillation is around 75% regardless of the ammonia concentration of the biogas slurry. The recovered ammonia is used for CO 2 absorption to realize simultaneous biogas upgrading and fertilizer generation. CO 2 absorption performance of the recovered ammonia (absorption capacity and rate) is compared with a conventional model absorbent. Theoretical results on biogas upgrading are also provided. After ammonia recovery, the treated biogas slurry has significantly reduced phytotoxicity, improving the applicability for agricultural irrigation. The novel concept demonstrated in this study shows great potential in closing the CO 2 loop in biogas production by recycling ammonia as an absorbent for CO 2 absorption associated with producing fertilizers.

Oxide ceramics

International Nuclear Information System (INIS)

Ryshkewitch, E.; Richerson, D.W.

1985-01-01

The book explores single-phase ceramic oxide systems from the standpoint of physical chemistry and technology. This second edition also focuses on advances in technology since publication of the original edition. These include improvements in raw materials and forming and sintering techniques, and the major role that oxide ceramics have had in development of advanced products and processes. The text is divided into five major sections: general fundamentals of oxide ceramics, advances in aluminum oxide technology, advances in zirconia technology, and advances in beryllium oxide technology

Calreticulin discriminates the proximal region at the N-glycosylation site of Glc1Man9GlcNAc2 ligand

Energy Technology Data Exchange (ETDEWEB)

Hirano, Makoto; Adachi, Yuka [Department of Materials and Life Science, Seikei University, 3-3-1 Kichijoji-kita, Musashino, Tokyo 180-8633 (Japan); Ito, Yukishige [Synthetic Cellular Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); ERATO, Japan Science and Technology Agency, Ito Glycotrilogy Project, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Totani, Kiichiro, E-mail: ktotani@st.seikei.ac.jp [Department of Materials and Life Science, Seikei University, 3-3-1 Kichijoji-kita, Musashino, Tokyo 180-8633 (Japan)

2015-10-23

Calreticulin (CRT) is well known as a lectin-like chaperone that recognizes Glc1Man9GlcNAc2 (G1M9)-glycoproteins in the endoplasmic reticulum (ER). However, whether CRT can directly interact with the aglycone moiety (protein portion) of the glycoprotein remains controversial. To improve our understanding of CRT interactions, structure-defined G1M9-derivatives with different aglycones (–OH, –Gly–NH{sub 2}, and –Gly–Glu–{sup t}Bu) were used as CRT ligands, and their interactions with recombinant CRT were analyzed using thermal shift analysis. The results showed that CRT binds strongly to a G1M9-ligand in the order –Gly–Glu–{sup t}Bu > –Gly–NH{sub 2} > –OH, which is the same as that of the reglucosylation of Man9GlcNAc2 (M9)-derivatives by the folding sensor enzyme UGGT (UDP-glucose: glycoprotein glucosyltransferase). Our results indicate that, similar to UGGT, CRT discriminates the proximal region at the N-glycosylation site, suggesting a similar mechanism mediating the recognition of aglycone moieties in the ER glycoprotein quality control system. - Highlights: • Glc1Man9GlcNAc2 (G1M9) ligands with different aglycones were chemically prepared. • Calreticulin (CRT) discriminates the aglycone of Glc1Man9GlcNAc2 (G1M9) ligand. • CRT binds with G1M9 ligands in a similar manner to folding sensor enzyme.

Y-TZP ceramic processing from coprecipitated powders: a comparative study with three commercial dental ceramics.

Science.gov (United States)

Lazar, Dolores R R; Bottino, Marco C; Ozcan, Mutlu; Valandro, Luiz Felipe; Amaral, Regina; Ussui, Valter; Bressiani, Ana H A

2008-12-01

(1) To synthesize 3mol% yttria-stabilized zirconia (3Y-TZP) powders via coprecipitation route, (2) to obtain zirconia ceramic specimens, analyze surface characteristics, and mechanical properties, and (3) to compare the processed material with three reinforced dental ceramics. A coprecipitation route was used to synthesize a 3mol% yttria-stabilized zirconia ceramic processed by uniaxial compaction and pressureless sintering. Commercially available alumina or alumina/zirconia ceramics, namely Procera AllCeram (PA), In-Ceram Zirconia Block (CAZ) and In-Ceram Zirconia (IZ) were chosen for comparison. All specimens (6mmx5mmx5mm) were polished and ultrasonically cleaned. Qualitative phase analysis was performed by XRD and apparent densities were measured on the basis of Archimedes principle. Ceramics were also characterized using SEM, TEM and EDS. The hardness measurements were made employing Vickers hardness test. Fracture toughness (K(IC)) was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's test (alpha=0.05). ANOVA revealed that the Vickers hardness (pceramic materials composition. It was confirmed that the PA ceramic was constituted of a rhombohedral alumina matrix, so-called alpha-alumina. Both CAZ and IZ ceramics presented tetragonal zirconia and alpha-alumina mixture of phases. The SEM/EDS analysis confirmed the presence of aluminum in PA ceramic. In the IZ and CAZ ceramics aluminum, zirconium and cerium in grains involved by a second phase containing aluminum, silicon and lanthanum were identified. PA showed significantly higher mean Vickers hardness values (H(V)) (18.4+/-0.5GPa) compared to vitreous CAZ (10.3+/-0.2GPa) and IZ (10.6+/-0.4GPa) ceramics. Experimental Y-TZP showed significantly lower results than that of the other monophased ceramic (PA) (pceramics (pceramic processing conditions led to ceramics with mechanical properties comparable to commercially available reinforced ceramic materials.

Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

Science.gov (United States)

Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert

2016-01-12

A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.

Roles of renal ammonia metabolism other than in acid-base homeostasis.

Science.gov (United States)

Weiner, I David

2017-06-01

The importance of renal ammonia metabolism in acid-base homeostasis is well known. However, the effects of renal ammonia metabolism other than in acid-base homeostasis are not as widely recognized. First, ammonia differs from almost all other solutes in the urine in that it does not result from arterial delivery. Instead, ammonia is produced by the kidney, and only a portion of the ammonia produced is excreted in the urine, with the remainder returned to the systemic circulation through the renal veins. In normal individuals, systemic ammonia addition is metabolized efficiently by the liver, but in patients with either acute or chronic liver disease, conditions that increase the addition of ammonia of renal origin to the systemic circulation can result in precipitation and/or worsening of hyperammonemia. Second, ammonia appears to serve as an intrarenal paracrine signaling molecule. Hypokalemia increases proximal tubule ammonia production and secretion as well as reabsorption in the thick ascending limb of the loop of Henle, thereby increasing delivery to the renal interstitium and the collecting duct. In the collecting duct, ammonia decreases potassium secretion and stimulates potassium reabsorption, thereby decreasing urinary potassium excretion and enabling feedback correction of the initiating hypokalemia. Finally, the stimulation of renal ammonia metabolism by hypokalemia may contribute to the development of metabolic alkalosis, which in turn can stimulate NaCl reabsorption and contribute to the intravascular volume expansion, increased blood pressure and diuretic resistance that can develop with hypokalemia. The evidence supporting these novel non-acid-base roles of renal ammonia metabolism is discussed in this review.

A fractographic study of clinically retrieved zirconia–ceramic and metal–ceramic fixed dental prostheses

Science.gov (United States)

Pang, Zhen; Chughtai, Asima; Sailer, Irena; Zhang, Yu

2015-01-01

Objectives A recent 3-year randomized controlled trial (RCT) of tooth supported three- to five-unit zirconia–ceramic and metal–ceramic posterior fixed dental prostheses (FDPs) revealed that veneer chipping and fracture in zirconia–ceramic systems occurred more frequently than those in metal–ceramic systems [1]. This study seeks to elucidate the underlying mechanisms responsible for the fracture phenomena observed in this RCT using a descriptive fractographic analysis. Methods Vinyl-polysiloxane impressions of 12 zirconia–ceramic and 6 metal–ceramic FDPs with veneer fractures were taken from the patients at the end of a mean observation of 40.3 ± 2.8 months. Epoxy replicas were produced from these impressions [1]. All replicas were gold coated, and inspected under the optical microscope and scanning electron microscope (SEM) for descriptive fractography. Results Among the 12 zirconia–ceramic FDPs, 2 had small chippings, 9 had large chippings, and 1 exhibited delamination. Out of 6 metal–ceramic FDPs, 5 had small chippings and 1 had large chipping. Descriptive fractographic analysis based on SEM observations revealed that fracture initiated from the wear facet at the occlusal surface in all cases, irrespective of the type of restoration. Significance Zirconia–ceramic and metal–ceramic FDPs all fractured from microcracks that emanated from occlusal wear facets. The relatively low fracture toughness and high residual tensile stress in porcelain veneer of zirconia restorations may contribute to the higher chipping rate and larger chip size in zirconia–ceramic FDPs relative to their metal–ceramic counterparts. The low veneer/core interfacial fracture energy of porcelain-veneered zirconia may result in the occurrence of delamination in zirconia–ceramic FDPs. PMID:26233469

[Comparison of color reappearance between metal-ceram restoration and foundry-ceram restoration using crystaleye spectrophotometer].

Science.gov (United States)

Shi, Tao; Zhang, Ning; Kong, Fan-wen; Zhan, De-song

2010-10-01

To study the color reappearance effect of metal-ceram restoration and foundry-ceram restoration using Crystaleye spectrophotometer. 58 metal-ceram restorations and 58 foundry-ceram restorations according to the result of the Crystaleye spectrophotometer were made respectively. The deltaE between restorations and natural teeth as referenced were analyzed. And satisfaction of dentists and patients were evaluated. The deltaE between metal-ceram restorations and natural teeth was 7.13 +/- 0.74. The deltaE between foundry-ceram restorations and teeth was 1.47 +/- 0.84. There were statistical differences between the deltaE (P spectrophotometer can provide accurate reference for foundry-ceram restoration, but for metal-ceram restoration it is not accurate.

Ammonia emissions in Europe

DEFF Research Database (Denmark)

Jacobsen, Brian H.

2012-01-01

The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the la......The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries...

The role of O-linked GlcNAc modification on the glucose response of ChREBP

Energy Technology Data Exchange (ETDEWEB)

Sakiyama, Haruhiko [Department of Biochemistry, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Fujiwara, Noriko, E-mail: noriko-f@hyo-med.ac.jp [Department of Biochemistry, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Noguchi, Takahiro; Eguchi, Hironobu; Yoshihara, Daisaku [Department of Biochemistry, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Uyeda, Kosaku [Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, TX 75390-9038 (United States); Suzuki, Keiichiro [Department of Biochemistry, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan)

2010-11-26

Research highlights: {yields} The O-linked GlcNAc modification is crucial for the glucose response. {yields} Mlx is required for nuclear localization and transcription activity of ChREBP. {yields} The presence of Mlx stabilizes ChREBP protein. -- Abstract: The carbohydrate response element-binding protein (ChREBP) functions as a transcription factor in mediating the glucose-activated gene expression of multiple liver enzymes, which are responsible for converting excess carbohydrate to storage fat. ChREBP is translocated into the nucleus in response to high glucose levels, and then up-regulates transcriptional activity. Although this glucose activation of ChREBP is generally observed only in liver cells, overexpression of wild type max-like protein X (Mlx), but not an inactive mutant Mlx, resulted in the exhibition of the ChREBP functions also in a human kidney cell line. Because high glucose conditions induce the glycosylation of cellular proteins, the effect of O-linked GlcNAc modification on ChREBP functions was examined. Treatment with an O-GlcNAcase inhibitor (PUGNAc), which increases the O-linked GlcNAc modification of cellular proteins, caused an increase in the glucose response of ChREBP. In contrast, treatment with a glutamine fructose amidotransferase inhibitor (DON), which decreases O-GlcNAcylation by inhibiting the hexosamine biosynthetic pathway, completely blocked the glucose response of ChREBP. These results suggest that the O-linked glycosylation of ChREBP itself or other proteins that regulate ChREBP is essential for the production of functional ChREBP.

Werkstoffwoche 98. Vol. 7. Symposium 9: Ceramics. Symposium 14: Simulation of ceramics

International Nuclear Information System (INIS)

Heinrich, J.; Ziegler, G.; Hermel, W.; Riedel, H.

1999-01-01

The leading subject of this proceedings volume is ceramic materials, with papers on the following subject clusters: Processing (infiltration, sintering, forming) - Physics and chemistry of ceramics (functional ceramics, SiC, ceramic precursors, microstructural properties) - Novel concepts (composites, damage induced by oxidation and mechanical stress, performance until damage under mechanical and thermal stress, layers, nanocomposites). 28 of the conference papers have been prepared for individual retrieval from the ENERGY database. (orig./CB) [de

Basic Physical Properties of Ammonia-Rich Ice

Science.gov (United States)

Shandera, S. E.; Lorenz, R. D.

2000-10-01

We report simple measurements of the thermal conductivity, mechanical strength and microwave absorptivity of ammonia hydrate ices, which are likely to be abundant in the Saturnian system. Understanding the dielectric properties of ammonia ice could play an important role in interpreting data from the Cassini spacecraft, which will image Titan's surface by radar in 2004. Thermal conductivity measurements were made by freezing a thin copper wire in the center of ice samples. The wire acted as both heater and temperature sensor, calibrated by a thermocouple also frozen in the sample. Ices with concentrations of 5- 30% ammonia were compared to pure water ice and ices containing salts. Thermal conductivity was found to decrease with increasing concentration of ammonia - a factor of 3 or 4 less than pure water ice for the 30% peritectic composition. Microwave absorptivity was measured by placing insulated ice samples and calibration materials in a conventional microwave oven. The microwave absorptivity was found to increase with increasing concentration of ammonia, although the effect is strongly temperature dependent, and heat leak from the room made quantitative measurement difficult. Mechanical strength was estimated using a ball bearing/accelerometer indentation method. For temperatures 100-150K, ammonia-rich ice has a Young's modulus about 10x smaller than pure ice. These properties affect tidal dissipation and the likelihood and style of cryovolcanism on (and the radar appearance of) the icy satellites and Titan. This work was supported by the Cassini RADAR team and the Arizona Space Grant Consortium.

Flight-vehicle materials, structures, and dynamics - Assessment and future directions. Vol. 3 - Ceramics and ceramic-matrix composites

Science.gov (United States)

Levine, Stanley R. (Editor)

1992-01-01

The present volume discusses ceramics and ceramic-matrix composites in prospective aerospace systems, monolithic ceramics, transformation-toughened and whisker-reinforced ceramic composites, glass-ceramic matrix composites, reaction-bonded Si3N4 and SiC composites, and chemical vapor-infiltrated composites. Also discussed are the sol-gel-processing of ceramic composites, the fabrication and properties of fiber-reinforced ceramic composites with directed metal oxidation, the fracture behavior of ceramic-matrix composites (CMCs), the fatigue of fiber-reinforced CMCs, creep and rupture of CMCs, structural design methodologies for ceramic-based materials systems, the joining of ceramics and CMCs, and carbon-carbon composites.

What every surgeon should know about Ceramic-on-Ceramic bearings in young patients.

Science.gov (United States)

Hernigou, Philippe; Roubineau, François; Bouthors, Charlie; Flouzat-Lachaniette, Charles-Henri

2016-04-01

Based on the exceptional tribological behaviour and on the relatively low biological activity of ceramic particles, Ceramic-on-Ceramic (CoC) total hip arthroplasty (THA) presents significant advantagesCoC bearings decrease wear and osteolysis, the cumulative long-term risk of dislocation, muscle atrophy, and head-neck taper corrosion.However, there are still concerns regarding the best technique for implantation of ceramic hips to avoid fracture, squeaking, and revision of ceramic hips with fracture of a component.We recommend that surgeons weigh the potential advantages and disadvantages of current CoC THA in comparison with other bearing surfaces when considering young very active patients who are candidates for THA. Cite this article: Hernigou P, Roubineau F, Bouthors C, Flouzat-Lachaniette C-H. What every surgeon should know about Ceramic-on-Ceramic bearings in young patients. EFORT Open Rev 2016;1:107-111. DOI: 10.1302/2058-5241.1.000027.