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Sample records for denitrifying enrichment cultures

  1. Enrichment of denitrifying methanotrophic bacteria for application after direct low-temperature anaerobic sewage treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kampman, Christel, E-mail: christel.kampman@wur.nl [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands); Hendrickx, Tim L.G. [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands); Luesken, Francisca A.; Alen, Theo A. van; Op den Camp, Huub J.M.; Jetten, Mike S.M. [Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Zeeman, Grietje; Buisman, Cees J.N.; Temmink, Hardy [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer A new concept for low-temperature anaerobic sewage treatment is proposed. Black-Right-Pointing-Pointer In this concept, denitrification and methane oxidation are performed by Methylomirabilis oxyfera. Black-Right-Pointing-Pointer The bacteria were enriched from fresh water sediment using sequencing fed-batch reactors. Black-Right-Pointing-Pointer The volumetric consumption rate has to be increased by an order of magnitude for practical application. Black-Right-Pointing-Pointer Further research should focus on systems with improved biomass retention. - Abstract: Despite many advantages of anaerobic sewage treatment over conventional activated sludge treatment, it has not yet been applied in temperate zones. This is especially because effluent from low-temperature anaerobic treatment contains nitrogen and dissolved methane. The presence of nitrogen and methane offers the opportunity to develop a reactor in which methane is used as electron donor for denitrification. Such a reactor could be used in a new concept for low-temperature anaerobic sewage treatment, consisting of a UASB-digester system, a reactor for denitrification coupled to anaerobic methane oxidation, and a nitritation reactor. In the present study denitrifying methanotrophic bacteria similar to 'Candidatus Methylomirabilis oxyfera' were enriched. Maximum volumetric nitrite consumption rates were 33.5 mg NO{sub 2}{sup -}-N/L d (using synthetic medium) and 37.8 mg NO{sub 2}{sup -}-N/L d (using medium containing effluent from a sewage treatment plant), which are similar to the maximum rate reported so far. Though the goal was to increase the rates, in both reactors, after reaching these maximum rates, volumetric nitrite consumption rates decreased in time. Results indicate biomass washout may have significantly decelerated enrichment. Therefore, to obtain higher volumetric consumption rates, further research should focus on systems with complete biomass retention.

  2. Enrichment of denitrifying methanotrophic bacteria for application after direct low-temperature anaerobic sewage treatment

    International Nuclear Information System (INIS)

    Highlights: ? A new concept for low-temperature anaerobic sewage treatment is proposed. ? In this concept, denitrification and methane oxidation are performed by Methylomirabilis oxyfera. ? The bacteria were enriched from fresh water sediment using sequencing fed-batch reactors. ? The volumetric consumption rate has to be increased by an order of magnitude for practical application. ? Further research should focus on systems with improved biomass retention. - Abstract: Despite many advantages of anaerobic sewage treatment over conventional activated sludge treatment, it has not yet been applied in temperate zones. This is especially because effluent from low-temperature anaerobic treatment contains nitrogen and dissolved methane. The presence of nitrogen and methane offers the opportunity to develop a reactor in which methane is used as electron donor for denitrification. Such a reactor could be used in a new concept for low-temperature anaerobic sewage treatment, consisting of a UASB-digester system, a reactor for denitrification coupled to anaerobic methane oxidation, and a nitritation reactor. In the present study denitrifying methanotrophic bacteria similar to ‘Candidatus Methylomirabilis oxyfera’ were enriched. Maximum volumetric nitrite consumption rates were 33.5 mg NO2?-N/L d (using synthetic medium) and 37.8 mg NO2?-N/L d (using medium containing effluent from a sewage treatment plant), which are similar to the maximum rate reported so far. Though the goal was to increase the rates, in both reactors, after reaching these maximum rates, volumetric nitrite consumption rates decreased in time. Results indicate biomass washout may have significantly decelerated enrichment. Therefore, to obtain higher volumetric consumption rates, further research should focus on systems with complete biomass retention.

  3. Acute and chronic responses of denitrifying culture to diclofenac.

    Science.gov (United States)

    Ozdemir, Gamze; Aydin, Egemen; Topuz, Emel; Yangin-Gomec, Cigdem; Okutman Tas, Didem

    2015-01-01

    Acute and chronic effect as well as biodegradation potential at different sludge retention times (SRTs) of a priority pollutant, diclofenac on denitrification process was assessed. The continuous amendment of the culture for 6months with 1?g/L diclofenac resulted in 30% decrease in gas production. The average diclofenac removal observed in the diclofenac-acclimated culture was less than 15%. Batch tests showed that nitrate was removed in diclofenac free-control reactor at a higher rate compared to diclofenac amended reactor. Although, SRT did not have any progressive effect on diclofenac degradation, the system operated at low SRT was more sensitive to diclofenac and resulted in an increase in N2O emission. Wastewater treatment plants (WWTPs) operated at higher SRTs may tolerate and recover from the adverse effects of such micropollutants. The study can lead to other researchers to understand the fate and effect of other emerging pollutants in the anoxic unit of WWTPs. PMID:25460991

  4. IDENTIFICATION AND ECOPHYSIOLOGY OF ACTIVE DENITRIFIERS IN ACTIVATED SLUDGE

    DEFF Research Database (Denmark)

    Hansen, Aviaja Anna; Le-Quy, Vang; Nielsen, Kåre Lehmann; Nielsen, Jeppe Lund

    2010-01-01

    Denitrification is of crucial importance for nitrogen removal in wastewater treatment. However, due to the polyphyletic taxonomy of denitrifiers, little is known about their community composition and ecophysiology and the available knowledge derives mainly from culture-dependent studies or enriched reactor studies. To obtain better identification of active denitrifying communities in full-scale wastewater treatment plants (WWTPs) we applied DNA-SIP with 13C-labelled substrates, and RT-PCR of exp...

  5. Functional characterization of heterotrophic denitrifying bacteria in activated sludge

    Scientific Electronic Library Online (English)

    Nishani, Ramdhani; Faizal, Bux.

    2007-04-01

    Full Text Available Wastewater treatment facilities are largely accountable for the detrimental enrichment of water bodies with nitrogenous compounds, resulting in eutrophication. Denitrification is of interest as a means of removing nitrates and nitrites from water supplies because they are also hazardous to human hea [...] lth. The integration of biological nutrient removal into conventional wastewater treatment processes has, however, failed to take into sufficient consideration the role of key microorganisms present, specifically denitrifying bacteria. The purpose of the study reported here was to group such heterotrophic denitrifying bacteria using a series of biochemical and molecular analyses, to achieve an improved understanding of their functions. The role of the denitrifying bacteria in reducing nitrate and nitrite was monitored using the colorimetric nitrate reduction test. The genetic diversity of the culture collection was investigated by the use of denaturing gradient gel electrophoresis (DGGE), which enabled the creation of a microbial population profile of eight predominant isolates. Batch experiments were conducted on these isolates, the results of which ultimately confirmed their classification according to their respective functions, namely, incomplete denitrifiers, true denitrifiers, sequential denitrifiers, and exclusive nitrite reducers.

  6. Cultural Enrichment through Community Action.

    Science.gov (United States)

    Wilson, O. J.

    This project was conceived as a technique for helping to eliminate a cultural void in the areas of art, music, and theatre in the service area of Western Kentucky University. To implement this concept, demonstrations were conducted in art, music, theatre, and in library and lecture resources in 16 counties over a four-year period. The attendance…

  7. Enrichment of high ammonia tolerant methanogenic culture

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov

    Ammonia is the major toxicant in full scale anaerobic digesters of animal wastes which are rich in proteins and/or urea, such as pig or poultry wastes. Ammonia inhibition decreases methane production rates, increases volatile fatty acids concentration and leads to economic losses for the biogas plants. The methods used today to counteract ammonia inhibition are slow and costexpensive. A new biological approach to avoid or counteract ammonia inhibition by using ammonia tolerant methanogens, could provide a sustainable solution for cost-effective digestion of abundant ammonia-rich wastes. The aim of the current study was to isolate and identify methanogenic cultures tolerant to high ammonia concentrations. A mixed methanogenic population was stepwise exposed to ammonia concentrations (1 to 9.26 g NH4+-N L-1) during an enrichment process with successive batch cultivations. The methanogenic population was derived from a full scale biogas reactor (Hashøj, Denmark), fed with 75% animal manure and 25% food industries organic waste. Basal anaerobic medium was used for the enrichment along with sodium acetate (1 g HAc L-1) as a carbon source. Fluorescence insitu hybridization (FISH) was used to determine microbial community composition. The outcome of the enrichment process was a mesophilic aceticlastic methanogenic enriched culture able to withstand high ammonia loads and utilize acetate and form methane stoichiometrically. FISH analysis showed that the methanogens of the enriched culture belonged exclusively to strict aceticlastic methanogens. Results obtained in this study, demonstrated for the first time that strictly aceticlastic methanogens, derived from an enriched culture, can efficiently produce methane under high ammonia levels.

  8. Highly enriched Betaproteobacteria growing anaerobically with p-xylene and nitrate

    DEFF Research Database (Denmark)

    Rotaru, Amelia-Elena; Probian, Christina; Wilkes, Heinz; Harder, Jens

    2010-01-01

    The identity of the microorganisms capable of anaerobic p-xylene degradation under denitrifying conditions is hitherto unknown. Here, we report highly enriched cultures of freshwater denitrifying bacteria that grow anaerobically with p-xylene as the sole organic carbon source and electron donor. Long curved rods, with 95% 16S rRNA gene sequence identity to Denitratisoma oestradiolicum, dominated the enrichment cultures (>91% of all cells), as detected by phylotype-specific probes. These Rhodocyc...

  9. Microbial Manganese Reduction by Enrichment Cultures from Coastal Marine Sediments

    OpenAIRE

    Burdige, David J.; Nealson, Kenneth H.

    1985-01-01

    Manganese reduction was catalyzed by enrichment cultures of anaerobic bacteria obtained from coastal marine sediments. In the absence of oxygen, these enrichment cultures reduced manganates when grown on either lactate, succinate, or acetate in both sulfate-free and sulfate-containing artificial seawaters. Sodium azide as well as oxygen completely inhibited microbial manganese reduction by these enrichment cultures, whereas molybdate had no effect on them. The addition of nitrate to the mediu...

  10. Enrichment and microbial characterization of syngas converting anaerobic cultures

    OpenAIRE

    Alves, J.I.; Visser, Michael; A. J. M. Stams; Plugge, Caroline M.; Alves, M. M.; Sousa, D. Z.

    2013-01-01

    Bioconversion of recalcitrant biomass/waste into bulk chemicals or biofuels is often not feasible. By gasification of these materials, syngas (mainly composed of CO2, CO and H2) is generated and can be used for the production of high value compounds by thermochemical or biotechnological processes. Here, three thermophilic cultures enriched with syngas mixtures or pure CO (T-Syn, T-Syn-CO and T-CO) were studied. Stable enriched cultures obtained by subsequent transfers for over a year, convert...

  11. Absence of microbial mineralization of lignin in anaerobic enrichment cultures.

    OpenAIRE

    Odier, E; Monties, B

    1983-01-01

    The existence of anaerobic biodegradation of lignin was examined in mixed microflora. Egyptian soil samples, in which rapid mineralization of organic matter takes place in the presence of an important anaerobic microflora, were used to obtain the anaerobic enrichment cultures for this study. Specifically, 14CO2 or [14C]lignin wood was used to investigate the release of labeled gaseous or soluble degradation products of lignin in microbial cultures. No conversion of 14C-labeled lignin to 14CO2...

  12. Methanogenic degradation of acetone by an enrichment culture

    OpenAIRE

    Platen, Harald; Schink, Bernhard

    1987-01-01

    An anaerobic enrichment culture degraded 1 mol of acetone to 2 tool of methane and 1 tool of carbon dioxide. Two microorganisms were involved in this process, a filament-forming rod similar to Methanothrix sp. and an unknown rod with round to slightly pointed ends. Both organisms formed aggregates up to 300 gm in diameter. No fluorescing bacteria were observed indicating that hydrogen or formate-utilizing methanogens are not involved in this process. Acetate was utilized in this culture by th...

  13. Immunological identification and distribution of dissimilatory heme cd1 and nonheme copper nitrite reductases in denitrifying bacteria.

    OpenAIRE

    Coyne, M S; Arunakumari, A; Averill, B A; Tiedje, J.M.

    1989-01-01

    Polyclonal antibodies were used to identify heme or copper nitrite reductases in the following groups: 23 taxonomically diverse denitrifiers from culture collections, 100 numerically dominant denitrifiers from geographically diverse environments, and 51 denitrifiers from a culture collection not selected for denitrification. Antisera were raised against heme nitrite reductases from Pseudomonas aeruginosa and Pseudomonas stutzeri and against copper nitrite reductase from Achromobacter cyclocla...

  14. Is enrichment culture necessary for the isolation of Campylobacter jejuni from faeces?

    OpenAIRE

    Hutchinson, D N; Bolton, F.J.

    1984-01-01

    The role of enrichment culture for the isolation of Campylobacter jejuni from faeces is discussed. It is concluded that enrichment culture is only necessary for those specimens where it is anticipated that the number of organisms is likely to be low. In a trial of a blood free enrichment broth (CCD broth) and the modified Preston enrichment broth the latter gave significantly superior results.

  15. Highly enriched Betaproteobacteria growing anaerobically with p-xylene and nitrate

    DEFF Research Database (Denmark)

    Rotaru, Amelia-Elena; Probian, Christina

    2010-01-01

    The identity of the microorganisms capable of anaerobic p-xylene degradation under denitrifying conditions is hitherto unknown. Here, we report highly enriched cultures of freshwater denitrifying bacteria that grow anaerobically with p-xylene as the sole organic carbon source and electron donor. Long curved rods, with 95% 16S rRNA gene sequence identity to Denitratisoma oestradiolicum, dominated the enrichment cultures (>91% of all cells), as detected by phylotype-specific probes. These Rhodocyclaceae microorganisms were distantly related to other denitrifying hydrocarbon-degrading Betaproteobacteria from the Azoarcus-Thauera clade. Complete oxidation p-xylene to CO(2) coupled to denitrification was suggested by quantitative measurements of substrate consumption. Metabolite analysis identified (4-methylbenzyl)succinate and (4-methylphenyl)itaconate, suggesting addition to fumarate as an initial activation reaction.

  16. Dimethylamine biodegradation by mixed culture enriched from drinking water biofilter.

    Science.gov (United States)

    Liao, Xiaobin; Chen, Chao; Zhang, Jingxu; Dai, Yu; Zhang, Xiaojian; Xie, Shuguang

    2015-01-01

    Dimethylamine (DMA) is one of the important precursors of drinking water disinfection by-product N-nitrosodimethylamine (NDMA). Reduction of DMA to minimize the formation of carcinogenic NDMA in drinking water is of practical importance. Biodegradation plays a major role in elimination of DMA pollution in the environment, yet information on DMA removal by drinking water biofilter is still lacking. In this study, microcosms with different treatments were constructed to investigate the potential of DMA removal by a mixed culture enriched from a drinking water biofilter and the effects of carbon and nitrogen sources. DMA could be quickly mineralized by the enrichment culture. Amendment of a carbon source, instead of a nitrogen source, had a profound impact on DMA removal. A shift in bacterial community structure was observed with DMA biodegradation, affected by carbon and nitrogen sources. Proteobacteria was the predominant phylum group in DMA-degrading microcosms. Microorganisms from a variety of bacterial genera might be responsible for the rapid DMA mineralization. PMID:25280176

  17. Complete Genome Sequence of Bacteroidales Strain CF from a Chloroform-Dechlorinating Enrichment Culture

    OpenAIRE

    Tang, Shuiquan; Edwards, Elizabeth A.

    2013-01-01

    Bacteroidales strain CF is the most abundant nondechlorinating organism in a Dehalobacter-containing enrichment culture that consistently reductively dechlorinates >50 mg/liter chloroform or 1,1,1-trichloroethane (methyl chloroform). We assembled and closed the complete genome sequence of this organism from the metagenomic sequencing data for enrichment cultures. This organism is predicted to ferment l-lactate and ethanol.

  18. Changes in Bacterial Species Composition in Enrichment Cultures with Various Dilutions of Inoculum as Monitored by Denaturing Gradient Gel Electrophoresis

    OpenAIRE

    Jackson, Colin R; Roden, Eric E; Churchill, Perry F.

    1998-01-01

    Denaturing gradient gel electrophoresis revealed changes in the bacterial species obtained from enrichment cultures with different inoculum dilutions. This inoculum dilution enrichment approach may facilitate the detection and isolation of a greater number of bacterial species than traditional enrichment techniques.

  19. Tetrachloroethene transformation to trichloroethene and cis-1,2-dichloroethene by sulfate-reducing enrichment cultures.

    OpenAIRE

    Bagley, D M; Gossett, J M

    1990-01-01

    Tetrachloroethene, also known as perchloroethylene, was reductively dechlorinated to trichloroethene and cis-1,2-dichloroethene by laboratory sulfate-reducing enrichment cultures. The causative organism or group was not identified. However, tetrachloroethene was dechlorinated to trichloroethene in 50 mM bromoethane-sulfonate-inhibited enrichments and to trichloroethene and cis-1,2-dichloroethene in 3 mM fluoroacetate-inhibited enrichments. Overall transformation varied from 92% tetrachloroeth...

  20. Utilization of aminoaromatic acids by a methanogenic enrichment culture and by a novel Citrobacter freundii strain

    OpenAIRE

    Savelieva, O.; Kotova, I.; Roelofsen, W; A. J. M. Stams; Netrusov, A.

    2004-01-01

    Following incubation of mesophilic methanogenic floccular sludge from a lab-scale upflow anaerobic sludge bed reactor used to treat cattle manure wastewater, a stable 5-aminosalicylate-degrading enrichment culture was obtained. Subsequently, a Citrobacter freundii strain, WA1, was isolated from the 5-aminosalicylate-degrading methanogenic consortium. The methanogenic enrichment culture degraded 5-aminosalicylate completely to CH4, CO2 and NH4 , while C. freundii strain WA1 reduced 5-aminosal...

  1. Characterization of a Highly Enriched Dehalococcoides-Containing Culture That Grows on Vinyl Chloride and Trichloroethene

    OpenAIRE

    Duhamel, Melanie; Mo, Kaiguo; Edwards, Elizabeth A.

    2004-01-01

    A highly enriched culture that reductively dechlorinates trichloroethene (TCE), cis-1,2-dichloroethene (cDCE), and vinyl chloride (VC) to ethene without methanogenesis is described. The Dehalococcoides strain in this enrichment culture had a yield of (5.6 ± 1.4) × 108 16S rRNA gene copies/?mol of Cl? when grown on VC and hydrogen. Unlike the other VC-degrading cultures described in the literature, strains VS and BAV1, this culture maintained the ability to grow on TCE with a yield of (3.6 ± 1...

  2. Enrichment methodology to increase the positivity of cultures from body fluids

    Scientific Electronic Library Online (English)

    Alessandra Valle, Daur; Francisco, Klimak Jr.; Laura Lúcia, Cogo; Gislene Diógenes, Botão; Cristina Leise Bastos, Monteiro; Libera Maria, Dalla Costa.

    2006-12-01

    Full Text Available Isolation and identification of etiological agents found in body fluids can be of critical importance for the recovery of patients suffering from potentially-severe infections, which are often followed by serious sequels. Eighty-two samples of different body fluids were analyzed using two different [...] methods: (1) the conventional culture method (agar plating) and (2) the enrichment culture technique, using the Bact/Alert® blood culture bottle. The number of positive cultures increased on average from 9.7% to 23.1% with the enrichment culture technique. Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus were the most frequently isolated bacteria. The enrichment method could provide a more accurate means the identifying etiological agents.

  3. Enrichment methodology to increase the positivity of cultures from body fluids

    Directory of Open Access Journals (Sweden)

    Alessandra Valle Daur

    2006-12-01

    Full Text Available Isolation and identification of etiological agents found in body fluids can be of critical importance for the recovery of patients suffering from potentially-severe infections, which are often followed by serious sequels. Eighty-two samples of different body fluids were analyzed using two different methods: (1 the conventional culture method (agar plating and (2 the enrichment culture technique, using the Bact/Alert® blood culture bottle. The number of positive cultures increased on average from 9.7% to 23.1% with the enrichment culture technique. Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus were the most frequently isolated bacteria. The enrichment method could provide a more accurate means the identifying etiological agents.

  4. Co-occurrence of Methanosarcina mazei and Geobacteraceae in an iron (III)-reducing enrichment culture

    Science.gov (United States)

    Zheng, Shiling; Zhang, Hongxia; Li, Ying; Zhang, Hua; Wang, Oumei; Zhang, Jun; Liu, Fanghua

    2015-01-01

    Methanosaeta harundinacea and Methanosarcina barkeri, known as classic acetoclastic methanogens, are capable of directly accepting electrons from Geobacter metallireducens for the reduction of carbon dioxide to methane, having been revealed as direct interspecies electron transfer (DIET) in the laboratory co-cultures. However, whether their co-occurrences are ubiquitous in the iron (III)-reducing environments and the other species of acetoclastic methanogens such as Methanosarcina mazei are capable of DIET are still unknown. Instead of initiating the co-cultures with pure cultures, two-step cultivation was employed to selectively enrich iron (III)-reducing microorganisms in a coastal gold mining river, Jiehe River, with rich iron content in the sediments. First, iron (III) reducers including Geobacteraceae were successfully enriched by 3-months successive culture on amorphous Fe(III) oxides as electron acceptor and acetate as electron donor. High-throughput Illumina sequencing, terminal restriction fragment length polymorphism (T-RFLP) and clone library analysis based on 16S rRNA genes revealed that the enrichment cultures actively contained the bacteria belong to Geobacteraceae and Bacilli, exclusively dominated by the archaea belong to Methanosarcinaceae. Second, the enrichment cultures including methanogens and Geobacteraceae were transferred with ethanol as alternative electron donor. Remarkably, aggregates were successively formed in the enrichments after three transfers. The results revealed by RNA-based analysis demonstrate that the co-occurrence of Methanosarcina mazei and Geobacteraceae in an iron (III)-reducing enrichment culture. Furthermore, the aggregates, as close physical contact, formed in the enrichment culture, indicate that DIET could be a possible option for interspecies electron transfer in the aggregates. PMID:26441876

  5. Enhanced production and isotope enrichment of recombinant glycoproteins produced in cultured mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Skelton, David; Goodyear, Abbey [Florida State University, Department of Chemistry and Biochemistry (United States); Ni, DaQun; Walton, Wendy J.; Rolle, Myron; Hare, Joan T. [Florida State University, Institute of Molecular Biophysics (United States); Logan, Timothy M., E-mail: tlogan@fsu.ed [Florida State University, Department of Chemistry and Biochemistry (United States)

    2010-10-15

    NMR studies of post-translationally modified proteins are complicated by the lack of an efficient method to produce isotope enriched recombinant proteins in cultured mammalian cells. We show that reducing the glucose concentration and substituting glutamate for glutamine in serum-free medium increased cell viability while simultaneously increasing recombinant protein yield and the enrichment of non-essential amino acids compared to culture in unmodified, serum-free medium. Adding dichloroacetate, a pyruvate dehydrogenase kinase inhibitor, further improves cell viability, recombinant protein yield, and isotope enrichment. We demonstrate the method by producing partially enriched recombinant Thy1 glycoprotein from Lec1 Chinese hamster ovary (CHO) cells using U-{sup 13}C-glucose and {sup 15}N-glutamate as labeled precursors. This study suggests that uniformly {sup 15}N,{sup 13}C-labeled recombinant proteins may be produced in cultured mammalian cells starting from a mixture of labeled essential amino acids, glucose, and glutamate.

  6. Enhanced production and isotope enrichment of recombinant glycoproteins produced in cultured mammalian cells

    International Nuclear Information System (INIS)

    NMR studies of post-translationally modified proteins are complicated by the lack of an efficient method to produce isotope enriched recombinant proteins in cultured mammalian cells. We show that reducing the glucose concentration and substituting glutamate for glutamine in serum-free medium increased cell viability while simultaneously increasing recombinant protein yield and the enrichment of non-essential amino acids compared to culture in unmodified, serum-free medium. Adding dichloroacetate, a pyruvate dehydrogenase kinase inhibitor, further improves cell viability, recombinant protein yield, and isotope enrichment. We demonstrate the method by producing partially enriched recombinant Thy1 glycoprotein from Lec1 Chinese hamster ovary (CHO) cells using U-13C-glucose and 15N-glutamate as labeled precursors. This study suggests that uniformly 15N,13C-labeled recombinant proteins may be produced in cultured mammalian cells starting from a mixture of labeled essential amino acids, glucose, and glutamate.

  7. Characterization of an Enriched Anaerobic Culture Having Ability to Dechlorinate TCE

    Science.gov (United States)

    Ise, K.; Suto, K.; Inoue, C.

    2007-03-01

    An anaerobic mixed microbial culture was enriched from soil and groundwater taken from a site contaminated with trichloroethene (TCE). This enrichment culture could dechlorinate TCE sequentially to cis-dichloroethene (cis-DCE), vinyl chloride (VC), and ethene rapidly within 2 weeks. This enrichment culture could utilize various organic compounds, such as methanol, ethanol, and sodium acetate and so on, as electron donor. This culture had maintained high ability of TCE dechlorination for about 3 years since the start of enrichment cultivation. The optimum pH value for the dechlorination activity of this culture, which reacts from TCE to ethene, was 6.7. However above the pH value 7.1, it lost the dechlorination ability of cis-DCE and VC. So cis-DCE was remained at that pH conditions. From the DNA sequencing analysis of 16SrRNA gene, this enrichment culture includes Dehalococcoides sp. which has the ability to dechlorinate TCE to VC completely with hydrogen. It suggested that this Dehalococcoides sp. takes part in the dechlorination of chloroethenes.

  8. Use of ?-hexachlorocyclohexane as a terminal electron acceptor by an anaerobic enrichment culture.

    Science.gov (United States)

    Elango, Vijai; Kurtz, Harry D; Anderson, Christina; Freedman, David L

    2011-12-15

    The use of ?-hexachlorocyclohexane (HCH) as a terminal electron acceptor via organohalide respiration was demonstrated for the first time with an enrichment culture grown in a sulfate-free HEPES-buffered anaerobic mineral salts medium. The enrichment culture was initially developed with soil and groundwater from an industrial site contaminated with HCH isomers, chlorinated benzenes, and chlorinated ethenes. When hydrogen served as the electron donor, 79-90% of the electron equivalents from hydrogen were used by the enrichment culture for reductive dechlorination of the ?-HCH, which was provided at a saturation concentration of approximately 10 mg/L. Benzene and chlorobenzene were the only volatile transformation products detected, accounting for 25% and 75% of the ?-HCH consumed (on a molar basis), respectively. The enrichment culture remained active with only hydrogen as the electron donor and ?-HCH as the electron acceptor through several transfers to fresh mineral salts medium for more than one year. Addition of vancomycin to the culture significantly slowed the rate of ?-HCH dechlorination, suggesting that a Gram-positive organism is responsible for the reduction of ?-HCH. Analysis of the ?-HCH dechlorinating enrichment culture did not detect any known chlororespiring genera, including Dehalobacter. In bicarbonate-buffered medium, reductive dechlorination of ?-HCH was accompanied by significant levels of acetogenesis as well as methanogenesis. PMID:21983168

  9. Use of {gamma}-hexachlorocyclohexane as a terminal electron acceptor by an anaerobic enrichment culture

    Energy Technology Data Exchange (ETDEWEB)

    Elango, Vijai, E-mail: velango@g.clemson.edu [Hazardous Substance Research Center/South and Southwest, Louisiana State University, 3221 Patrick Taylor Hall, Baton Rouge, LA 70803 (United States); Kurtz, Harry D. [Department of Genetics and Biochemistry, Clemson University, 100 Jordan Hall, Clemson, SC 29634 (United States); Anderson, Christina; Freedman, David L. [Department of Environmental Engineering and Earth Sciences, Box 340919, Clemson University, Clemson, SC 29634-0919 (United States)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Use of {gamma}-hexachlorocyclohexane as a terminal electron acceptor was demonstrated. Black-Right-Pointing-Pointer H{sub 2} served as the electron donor for an enrichment culture that dechlorinated {gamma}-HCH. Black-Right-Pointing-Pointer H{sub 2} consumption for acetogenesis and methanogenesis stopped in HEPES media. Black-Right-Pointing-Pointer Addition of vancomycin significantly slowed the rate of {gamma}-HCH dechlorination. Black-Right-Pointing-Pointer Previously identified chlororespiring microbes were not detected in the enrichment. - Abstract: The use of {gamma}-hexachlorocyclohexane (HCH) as a terminal electron acceptor via organohalide respiration was demonstrated for the first time with an enrichment culture grown in a sulfate-free HEPES-buffered anaerobic mineral salts medium. The enrichment culture was initially developed with soil and groundwater from an industrial site contaminated with HCH isomers, chlorinated benzenes, and chlorinated ethenes. When hydrogen served as the electron donor, 79-90% of the electron equivalents from hydrogen were used by the enrichment culture for reductive dechlorination of the {gamma}-HCH, which was provided at a saturation concentration of approximately 10 mg/L. Benzene and chlorobenzene were the only volatile transformation products detected, accounting for 25% and 75% of the {gamma}-HCH consumed (on a molar basis), respectively. The enrichment culture remained active with only hydrogen as the electron donor and {gamma}-HCH as the electron acceptor through several transfers to fresh mineral salts medium for more than one year. Addition of vancomycin to the culture significantly slowed the rate of {gamma}-HCH dechlorination, suggesting that a Gram-positive organism is responsible for the reduction of {gamma}-HCH. Analysis of the {gamma}-HCH dechlorinating enrichment culture did not detect any known chlororespiring genera, including Dehalobacter. In bicarbonate-buffered medium, reductive dechlorination of {gamma}-HCH was accompanied by significant levels of acetogenesis as well as methanogenesis.

  10. Use of ?-hexachlorocyclohexane as a terminal electron acceptor by an anaerobic enrichment culture

    International Nuclear Information System (INIS)

    Highlights: ? Use of ?-hexachlorocyclohexane as a terminal electron acceptor was demonstrated. ? H2 served as the electron donor for an enrichment culture that dechlorinated ?-HCH. ? H2 consumption for acetogenesis and methanogenesis stopped in HEPES media. ? Addition of vancomycin significantly slowed the rate of ?-HCH dechlorination. ? Previously identified chlororespiring microbes were not detected in the enrichment. - Abstract: The use of ?-hexachlorocyclohexane (HCH) as a terminal electron acceptor via organohalide respiration was demonstrated for the first time with an enrichment culture grown in a sulfate-free HEPES-buffered anaerobic mineral salts medium. The enrichment culture was initially developed with soil and groundwater from an industrial site contaminated with HCH isomers, chlorinated benzenes, and chlorinated ethenes. When hydrogen served as the electron donor, 79–90% of the electron equivalents from hydrogen were used by the enrichment culture for reductive dechlorination of the ?-HCH, which was provided at a saturation concentration of approximately 10 mg/L. Benzene and chlorobenzene were the only volatile transformation products detected, accounting for 25% and 75% of the ?-HCH consumed (on a molar basis), respectively. The enrichment culture remained active with only hydrogen as the electron donor and ?-HCH as the electron acceptor through several transfers to fresh mineral salts medium for more than one year. Addition of vancomycin to the culture significantly slowed the rate of ?-HCH dechlorination, suggesting that a Gram-positive organism is responsible for the reduction of ?-HCH. Analysis of the ?-HCH dechlorinating enrichment culture did not detect any known chlororespiring genera, including Dehalobacter. In bicarbonate-buffered medium, reductive dechlorination of ?-HCH was accompanied by significant levels of acetogenesis as well as methanogenesis.

  11. Characteristics of enriched cultures for bio-huff-`n`-puff tests at Jilin oil field

    Energy Technology Data Exchange (ETDEWEB)

    Xiu-Yuan Wang; Gang Dai; Yan-Fen Xue; Shu-Hua Xie [Institute of Microbiology, Beijing (China)] [and others

    1995-12-31

    Three enriched cultures (48, 15a, and 26a), selected from more than 80 soil and water samples, could grow anaerobically in the presence of crude oil at 30{degrees}C and could ferment molasses to gases and organic acids. Oil recovery by culture 48 in the laboratory model experiment was enhanced by 25.2% over the original reserves and by 53.7% over the residual reserves. Enriched culture 48 was composed of at least 4 species belonging to the genera Eubacterium, Fusobacterium, and Bacteroides. This enriched culture was used as inoculum for MEOR field trials at Jilin oil field with satisfactory results. The importance of the role of these isolates in EOR was confirmed by their presence and behavior in the fluids produced from the microbiologically treated reservoir.

  12. Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

    Energy Technology Data Exchange (ETDEWEB)

    Coyne, P.; Smith, G. [New Mexico State Univ., Las Cruces, NM (United States)

    1995-08-15

    This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments.

  13. Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

    International Nuclear Information System (INIS)

    This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments

  14. Direct Cloning from Enrichment Cultures, a Reliable Strategy for Isolation of Complete Operons and Genes from Microbial Consortia

    OpenAIRE

    Entcheva, Plamena; Liebl, Wolfgang; Johann, Andre; Hartsch, Thomas; Streit, Wolfgang R.

    2001-01-01

    Enrichment cultures of microbial consortia enable the diverse metabolic and catabolic activities of these populations to be studied on a molecular level and to be explored as potential sources for biotechnology processes. We have used a combined approach of enrichment culture and direct cloning to construct cosmid libraries with large (>30-kb) inserts from microbial consortia. Enrichment cultures were inoculated with samples from five environments, and high amounts of avidin were added to the...

  15. Ca2+ enrichment in culture medium potentiates effect of oligonucleotides.

    Science.gov (United States)

    Hori, Shin-Ichiro; Yamamoto, Tsuyoshi; Waki, Reiko; Wada, Shunsuke; Wada, Fumito; Noda, Mio; Obika, Satoshi

    2015-10-30

    Antisense and RNAi-related oligonucleotides have gained attention as laboratory tools and therapeutic agents based on their ability to manipulate biological events in vitro and in vivo. We show that Ca(2+) enrichment of medium (CEM) potentiates the in vitro activity of multiple types of oligonucleotides, independent of their net charge and modifications, in various cells. In addition, CEM reflects in vivo silencing activity more consistently than conventional transfection methods. Microscopic analysis reveals that CEM provides a subcellular localization pattern of oligonucleotides resembling that obtained by unassisted transfection, but with quantitative improvement. Highly monodispersed nanoparticles ?100 nm in size are found in Ca(2+)-enriched serum-containing medium regardless of the presence or absence of oligonucleotides. Transmission electron microscopy analysis reveals that the 100-nm particles are in fact an ensemble of much smaller nanoparticles (? ? 15 nm). The presence of these nanoparticles is critical for the efficient uptake of various oligonucleotides. In contrast, CEM is ineffective for plasmids, which are readily transfected via the conventional calcium phosphate method. Collectively, CEM enables a more accurate prediction of the systemic activity of therapeutic oligonucleotides, while enhancing the broad usability of oligonucleotides in the laboratory. PMID:26101258

  16. Synergistic degradation of deca-BDE by an enrichment culture and zero-valent iron.

    Science.gov (United States)

    Chen, Xingjuan; Chen, Guilan; Qiu, Mengde; Sun, Guoping; Guo, Jun; Xu, Meiying

    2014-01-01

    Debromination of decabromodiphenyl ether (deca-BDE) by microbe and by zero-valent iron (ZVI) has been reported previously. However, no study has indicated the presence of microorganisms and their effect on ZVI-mediated reduction of deca-BDE. Synergistic degradation of deca-BDE by an enrichment culture and ZVI was studied. It was found that synergistic effects enhanced the debromination of deca-BDE as well as promoting the reduction of lower brominated products. ZVI stimulated microbial debromination by serving as an electron donor. Correlation analysis also confirmed that ZVI was capable of enhancing microbial population in the debromination of deca-BDE. Conversely, the enrichment culture produced acid which maintained pH stability and stimulated the oxidation of ZVI. The enrichment culture supplied its energy requirements by the oxidation of ZVI and concomitant reduction of deca-BDE, but incapable of growth and reduction of BDE-209 without ZVI and vice versa. Compared to the initial culture, the microbial community of the enrichment culture became dominated by several bacterial genera based on the results of 16S rRNA-gene pyrosequencing. PMID:24643388

  17. Anaerobic benzene degradation by iron- and sulfate-reducing enrichment cultures

    OpenAIRE

    Abu Laban, Nidal

    2010-01-01

    Anaerobic benzene degradation was studied with a sulfate- and an iron-reducing enrichment culture (BPL and BF). In culture BPL, molecular analysis revealed 95% dominance of a novel phylotype that is affiliated to the genus Pelotomaculum. To elucidate the initial activation mechanism of anaerobic benzene degradation, putative metabolites were screened revealing benzoate as a product of a carboxylation reaction. For identification of enzymes involved in anaerobic benzene degradation the whole p...

  18. Anaerobic Degradation of 2-Methylnaphthalene by a Sulfate-Reducing Enrichment Culture

    OpenAIRE

    Annweiler, Eva; Materna, Arne; Safinowski, Michael; Kappler, Andreas; Richnow, Hans H.; Michaelis, Walter; Meckenstock, Rainer U.

    2000-01-01

    Anaerobic degradation of 2-methylnaphthalene was investigated with a sulfate-reducing enrichment culture. Metabolite analyses revealed two groups of degradation products. The first group comprised two succinic acid adducts which were identified as naphthyl-2-methyl-succinic acid and naphthyl-2-methylene-succinic acid by comparison with chemically synthesized reference compounds. Naphthyl-2-methyl-succinic acid accumulated to 0.5 ?M in culture supernatants. Production of naphthyl-2-methyl-succ...

  19. Identification of active denitrifiers in full-scale nutrient removal wastewater treatment systems

    DEFF Research Database (Denmark)

    McIlroy, Simon Jon; Szyszka, Anna

    2015-01-01

    Denitrification is essential to the removal of nitrogen from wastewater during treatment, yet an understanding of the diversity of the active denitrifying bacteria responsible in full-scale wastewater treatment plants (WWTP) is lacking. In this study stable isotope probing (SIP) was applied in combination with microautoradiography (MAR)-fluorescence in situ hybridisation (FISH) to identify the active denitrifiers in a full-scale WWTP with biological N and P removal. Recognising that a range of carbon sources likely drive denitrification, a fully 13 C-labelled complex substrate was used for SIP incubations, under nitrite reducing conditions, in order to better capture the diversity of active denitrifiers present. Members of the Rhodoferax, Dechloromonas and Sulfuritalea were well represented in the 16S rRNA gene clone libraries from DNA enriched in 13 C, with FISH probes designed here for their in situ characterisation. FISH and MAR confirmed that they were core active denitrifiers in the community. The SIP clone library was additionally represented by a phylogenetically diverse group of organisms, with many previously not considered as important denitrifiers. The combined approach of SIP and MAR-FISH represents an excellent approach for identifying and characterising un-described diversity of active denitrifiers in full-scale systems.

  20. Two-stage mineralization of phenanthrene by estuarine enrichment cultures

    International Nuclear Information System (INIS)

    The polycyclic aromatic hydrocarbon phenanthrene was mineralized in two stages by soil, estuarine water, and sediment microbial populations. At high concentrations, phenanthrene was degraded, with the concomitant production of biomass and accumulation of Folin-Ciocalteau-reactive aromatic intermediates. Subsequent consumption of these intermediates resulted in a secondary increase in biomass. Analysis of intermediates by high-performance liquid chromatography, thin-layer chromatography, and UV absorption spectrometry showed 1-hydroxy-2-naphthoic acid (1H2NA) to be the predominant product. A less pronounced two-stage mineralization pattern was also observed by monitoring 14CO2 production from low concentrations (0.5 mg liter-1) of radiolabeled phenanthrene. Here, mineralization of 14C-labeled 1H2NA could explain the incremental 14CO2 produced during the later part of the incubations. Accumulation of 1H2NA by isolates obtained from enrichments was dependent on the initial phenanthrene concentration. The production of metabolites during polycyclic aromatic hydrocarbon biodegradation is discussed with regard to its possible adaptive significance and its methodological implications

  1. Oxygen regulation of nitrate uptake in denitrifying Pseudomonas aeruginosa.

    OpenAIRE

    Hernandez, D; Rowe, J J

    1987-01-01

    Oxygen had an immediate and reversible inhibitory effect on nitrate respiration by denitrifying cultures of Pseudomonas aeruginosa. Inhibition of nitrate utilization by oxygen appeared to be at the level of nitrate uptake, since nitrate reduction to nitrite in cell extracts was not affected by oxygen. The degree of oxygen inhibition was dependent on the concentration of oxygen, and increasing nitrate concentrations could not overcome the inhibition. The inhibitory effect of oxygen was maximal...

  2. CULTURAL ENRICHMENT THROUGH COMMUNITY ACTION PROJECT. ANNUAL REPORT FOR PERIOD ENDING JULY 1, 1967. (TITLE SUPPLIED).

    Science.gov (United States)

    WILSON, O.J.

    WESTERN KENTUCKY UNIVERSITY INITIATED A PROJECT TO DETERMINE THE CULTURAL NEEDS AND INTERESTS OF THE AREA IT SERVES. IN PHASE ONE, CITY AND COUNTY REPRESENTATIVES ATTENDED A SYMPOSIUM ON ART, MUSIC, LIBRARY, LECTURE, AND THEATER RESOURCES AND FORMED A REGIONAL ADVISORY COUNCIL FOR COMMUNITY ENRICHMENT. PHASE TWO WAS A WORKSHOP TO HELP COUNCIL…

  3. Who is actively denitrifying in activated sludge?

    DEFF Research Database (Denmark)

    Hansen, Aviaja Anna; Nielsen, Jeppe Lund

    2008-01-01

    Denitrification is of crucial importance in nitrogen removal from wastewater. However, due to the polyphyletic taxonomy of denitrifiers, little is known about the composition and ecophysiology of the actively denitrifying community in activated sludge. To identify the active denitrifiers in a full-scale wastewater treatment plant the transcripts (mRNA) of the nirS, nirK and nosZ denitrification genes expressed under acetate or amino acid consumption were amplified, sequenced and identified. This...

  4. Microbial characterization of anode-respiring bacteria within biofilms developed from cultures previously enriched in dissimilatory metal-reducing bacteria.

    Science.gov (United States)

    Pierra, Mélanie; Carmona-Martínez, Alessandro A; Trably, Eric; Godon, Jean-Jacques; Bernet, Nicolas

    2015-11-01

    This work evaluated the use of a culture enriched in DMRB as a strategy to enrich ARB on anodes. DMRB were enriched with Fe(III) as final electron acceptor and then transferred to a potentiostatically-controlled system with an anode as sole final electron acceptor. Three successive iron-enrichment cultures were carried out. The first step of enrichment revealed a successful selection of the high current-producing ARB Geoalkalibacter subterraneus. After few successive enrichment steps, the microbial community analysis in electroactive biofilms showed a significant divergence with an impact on the biofilm electroactivity. Enrichment of ARB in electroactive biofilms through the pre-selection of DMRB should therefore be carefully considered. PMID:26182995

  5. Microbial degradation of 2,4,6-trichloroaniline in aquatic samples and laboratory enrichment cultures

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, W.R.; Hoke, S.H.; Rosencrance, A.B.

    1984-01-01

    Microorganisms present in water samples obtained from a small tributary to the Gunpowder River in Maryland degraded 2,4,6-trichloroaniline following a prolonged acclimation period. Creek water sediments, but not the co-substate aniline, reduced the lag time prior to degradation. The microorganisms in the samples could be enriched to grow 2,4,6-trichloroaniline as indicated by increase in carbon dioxide, chloride, and adenosine triphosphate and by slight biomass increases accompanying the degradation of the compound. Uptake of 2,4,6-trichloroaniline by the enrichment population was as rapid as that of the original sample population but was without an apparent lag. Similar enrichment cultures could not be developed from five other sites.

  6. Comparative analysis of metagenomes from three methanogenic hydrocarbon-degrading enrichment cultures with 41 environmental samples.

    Science.gov (United States)

    Tan, Boonfei; Jane Fowler, S; Laban, Nidal Abu; Dong, Xiaoli; Sensen, Christoph W; Foght, Julia; Gieg, Lisa M

    2015-09-01

    Methanogenic hydrocarbon metabolism is a key process in subsurface oil reservoirs and hydrocarbon-contaminated environments and thus warrants greater understanding to improve current technologies for fossil fuel extraction and bioremediation. In this study, three hydrocarbon-degrading methanogenic cultures established from two geographically distinct environments and incubated with different hydrocarbon substrates (added as single hydrocarbons or as mixtures) were subjected to metagenomic and 16S rRNA gene pyrosequencing to test whether these differences affect the genetic potential and composition of the communities. Enrichment of different putative hydrocarbon-degrading bacteria in each culture appeared to be substrate dependent, though all cultures contained both acetate- and H2-utilizing methanogens. Despite differing hydrocarbon substrates and inoculum sources, all three cultures harbored genes for hydrocarbon activation by fumarate addition (bssA, assA, nmsA) and carboxylation (abcA, ancA), along with those for associated downstream pathways (bbs, bcr, bam), though the cultures incubated with hydrocarbon mixtures contained a broader diversity of fumarate addition genes. A comparative metagenomic analysis of the three cultures showed that they were functionally redundant despite their enrichment backgrounds, sharing multiple features associated with syntrophic hydrocarbon conversion to methane. In addition, a comparative analysis of the culture metagenomes with those of 41 environmental samples (containing varying proportions of methanogens) showed that the three cultures were functionally most similar to each other but distinct from other environments, including hydrocarbon-impacted environments (for example, oil sands tailings ponds and oil-affected marine sediments). This study provides a basis for understanding key functions and environmental selection in methanogenic hydrocarbon-associated communities. PMID:25734684

  7. Enriched rat primary ventral mesencephalic neurons as an in-vitro culture model.

    Science.gov (United States)

    Bollimpelli, Venkata S; Kondapi, Anand K

    2015-08-19

    Primary ventral mesencephalic (VM) neuronal cultures are gaining importance in the study of molecular mechanisms leading to Parkinson's disease and development of treatment strategies. In practice, these neurons are cocultured with glial cells, making assessment of neuronal specific proteomic and genomic analyses difficult. Hence, development of VM neuron-enriched culture is indispensable for such analyses. In the current study, VM neurons with less than 5% of glial cells in culture were found to survive for 9 days in vitro (DIV), followed by a sudden death phase resulting in less than 5% of neuronal viability. Analysis of expression of precursor and mature neuronal markers, Nestin and MAP-2, respectively, has shown that these VM neurons attain maturity at the 7th DIV both in the presence and in the absence of glial cells. This VM neuron-enriched culture was shown to be rich in dopaminergic neurons from 7th DIV and survived up to 10th DIV. Reactive oxygen species and DNA damage estimated using CMH2CDFDA dye and comet assay, respectively, showed an increase in their respective levels at 9th DIV. Furthermore, expression of topoisomerase II ?, a key player in neuronal development, was found to increase until 9th DIV, followed by a sudden decrease on 10th DIV. In conclusion, the above results provide a good working model of VM neurons in vitro along with 7th DIV as an ideal time period to study and evaluate the pro/antisurvival effects of various compounds on VM neurons. PMID:26164462

  8. Establishment and Characterization of an Anaerobic Thermophilic (55 degrees C) Enrichment Culture Degrading Long-Chain Fatty Acids

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Ahring, Birgitte Kiær

    1995-01-01

    A thermophilic, long-chain fatty acid-oxidizing culture was enriched. Stearate was used as the substrate, and methane and carbon dioxide were the sole end products. Cultivation was possible only when a fed-batch system was used or with addition of activated carbon or bentonite. The enrichment culture consisted of a short rod and two bacteria antigenically related to Methanobacterium thermoautotrophicum DELTA-H and Methanosarcina thermophila TM-1.

  9. Establishment and Characterization of an Anaerobic Thermophilic (55(deg)C) Enrichment Culture Degrading Long-Chain Fatty Acids

    OpenAIRE

    Angelidaki, I.; Ahring, B.K.

    1995-01-01

    A thermophilic, long-chain fatty acid-oxidizing culture was enriched. Stearate was used as the substrate, and methane and carbon dioxide were the sole end products. Cultivation was possible only when a fed-batch system was used or with addition of activated carbon or bentonite. The enrichment culture consisted of a short rod and two bacteria antigenically related to Methanobacterium thermoautotrophicum (Delta)H and Methanosarcina thermophila TM-1.

  10. Establishment and Characterization of an Anaerobic Thermophilic (55 degrees C) Enrichment Culture Degrading Long-Chain Fatty Acids

    OpenAIRE

    Angelidaki, Irini; Ahring, Birgitte Kiær

    2012-01-01

    A thermophilic, long-chain fatty acid-oxidizing culture was enriched. Stearate was used as the substrate, and methane and carbon dioxide were the sole end products. Cultivation was possible only when a fed-batch system was used or with addition of activated carbon or bentonite. The enrichment culture consisted of a short rod and two bacteria antigenically related to Methanobacterium thermoautotrophicum DELTA-H and Methanosarcina thermophila TM-1.

  11. Metatranscriptome of an Anaerobic Benzene-Degrading, Nitrate-Reducing Enrichment Culture Reveals Involvement of Carboxylation in Benzene Ring Activation

    OpenAIRE

    LUO, Fei; Gitiafroz, Roya; Devine, Cheryl E.; Gong, Yunchen; Hug, Laura A; Raskin, Lutgarde; Edwards, Elizabeth A.

    2014-01-01

    The enzymes involved in the initial steps of anaerobic benzene catabolism are not known. To try to elucidate this critical step, a metatranscriptomic analysis was conducted to compare the genes transcribed during the metabolism of benzene and benzoate by an anaerobic benzene-degrading, nitrate-reducing enrichment culture. RNA was extracted from the mixed culture and sequenced without prior mRNA enrichment, allowing simultaneous examination of the active community composition and the different...

  12. Denitrifying Bacteria in the Earthworm Gastrointestinal Tract and In Vivo Emission of Nitrous Oxide (N(inf2)O) by Earthworms

    OpenAIRE

    Karsten, G. R.; H. L. Drake

    1997-01-01

    Earthworms (Lumbricus rubellus and Octolasium lacteum) and gut homogenates did not produce CH(inf4), and methanogens were not readily culturable from gut material. In contrast, the numbers of culturable denitrifiers averaged 7 x 10(sup7) and 9 x 10(sup6) per g (dry weight) of gut material for L. rubellus and O. lacteum, respectively; these values were 256- and 35-fold larger than the numbers of culturable denitrifiers in the soil from which the earthworms were obtained. Anaerobically incubate...

  13. Metabolic characteristics of an aerobe isolated from a methylotrophic methanogenic enrichment culture

    Indian Academy of Sciences (India)

    Stephen V Rapheal; K R Swaminathan; K Lalitha

    2003-03-01

    An anaerobic methylotrophic methanogenic enrichment culture, with sustained metabolic characteristics, including that of methanation for over a decade, was the choice of the present study on interspecies interactions. Growth and methanation by the enrichment were suppressed in the presence of antibiotics, and no methanogen grown on methanol could be isolated using stringent techniques. The present study confirmed syntrophic metabolic interactions in this enrichment with the isolation of a strain of Pseudomonas sp. The organism had characteristic metabolic versatility in metabolizing a variety of substrates including alcohols, aliphatic acids, amino acids, and sugars. Anaerobic growth was favoured with nitrate in the growth medium. Cells grown anaerobically with methanol, revealed maximal nitrate reductase activity. Constitutive oxidative activity of the membrane system emerged from the high-specific oxygen uptake and nitrate reductase activities of the aerobically and anerobically grown cells respectively. Cells grown anaerobically on various alcohols effectively oxidized methanol in the presence of flavins, cofactor FAD and the methanogenic cofactor F420, suggesting a constitutive alcohol oxidizing capacity. In cells grown anaerobically on methanol, the rate of methanol oxidation with F420 was three times that of FAD. Efficient utilization of alcohols in the presence of F420 is a novel feature of the present study. The results suggest that utilization of methanol by the mixed culture would involve metabolic interactions between the Pseudomonas sp. and the methanogen(s). Methylotrophic, methanogenic partnership involving an aerobe is a novel feature hitherto unreported among anaerobic syntrophic associations and is of ecological significance.

  14. Bacterial community analysis of cypermethrin enrichment cultures and bioremediation of cypermethrin contaminated soils.

    Science.gov (United States)

    Akbar, Shamsa; Sultan, Sikander; Kertesz, Michael

    2015-07-01

    Cypermethrin is widely used for insect control; however, its toxicity toward aquatic life requires its complete removal from contaminated areas where the natural degradation ability of microbes can be utilized. Agricultural soil with extensive history of CM application was used to prepare enrichment cultures using cypermethrin as sole carbon source for isolation of cypermethrin degrading bacteria and bacterial community analysis using PCR-DGGE of 16?S rRNA gene. DGGE analysis revealed that dominant members of CM enrichment culture were associated with ?-proteobacteria followed by ?-proteobacteria, Firmicutes, and Actinobacteria. Three potential CM-degrading isolates identified as Ochrobactrum anthropi JCm1, Bacillus megaterium JCm2, and Rhodococcus sp. JCm5 degraded 86-100% of CM (100?mg?L(-1) ) within 10 days. These isolates were also able to degrade other pyrethroids, carbofuran, and cypermethrin degradation products. Enzyme activity assays revealed that enzymes involved in CM-degradation were inducible and showed activity when strains were grown on cypermethrin. Degradation kinetics of cypermethrin (200?mg?kg(-1)) in soils inoculated with isolates JCm1, JCm2, and JCm5 suggested time-dependent disappearance of cypermethrin with rate constants of 0.0516, 0.0425, and 0.0807?d(-1), respectively, following first order rate kinetics. The isolated bacterial strains were among dominant genera selected under CM enriched conditions and represent valuable candidates for in situ bioremediation of contaminated soils and waters. PMID:25656248

  15. Integrated biogas upgrading and hydrogen utilization in an anaerobic reactor containing enriched hydrogenotrophic methanogenic culture

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini

    2012-01-01

    Biogas produced by anaerobic digestion, is mainly used in a gas motor for heat and electricity production. However, after removal of CO2, biogas can be upgraded to natural gas quality, giving more utilization possibilities, such as utilization as autogas, or distant utilization by using the existing natural gas grid. The current study presents a new biological method for biogas upgrading in a separate biogas reactor, containing enriched hydrogenotrophic methanogens and fed with biogas and hydrogen. Both mesophilic- and thermophilic anaerobic cultures were enriched to convert CO2 to CH4 by addition of H2. Enrichment at thermophilic temperature (55°C) resulted in CO2 and H2 bioconversion rate of 320?mL CH4/(gVSS?h), which was more than 60% higher than that under mesophilic temperature (37°C). Different dominant species were found at mesophilic- and thermophilic-enriched cultures, as revealed by PCR–DGGE. Nonetheless, they all belonged to the order Methanobacteriales, which can mediate hydrogenotrophic methanogenesis. Biogas upgrading was then tested in a thermophilic anaerobic reactor under various operation conditions. By continuous addition of hydrogen in the biogas reactor, high degree of biogas upgrading was achieved. The produced biogas had a CH4 content, around 95% at steady-state, at gas (mixture of biogas and hydrogen) injection rate of 6?L/(L?day). The increase of gas injection rate to 12?L/(L?day) resulted in the decrease of CH4 content to around 90%. Further study showed that by decreasing the gas–liquid mass transfer by increasing the stirring speed of the mixture the CH4 content was increased to around 95%. Finally, the CH4 content around 90% was achieved in this study with the gas injection rate as high as 24?L/(L?day). Biotechnol. Bioeng. 2012; 109: 2729–2736. © 2012 Wiley Periodicals, Inc.

  16. Large scale production of Blackleg vaccine by fermenter and enriched culture medium in Iran

    Directory of Open Access Journals (Sweden)

    Pilehchian Langroudi, R.

    2012-06-01

    Full Text Available In all biological systems growth is defined as increase of chemical compounds. Bacteria can achieve to balanced growth if they are growing in a medium, which are completely adapted to it. Clostridium chauvoei, (Clostridium feseri is an anaerobic, spore forming, motile, and polymorph bacteria, which its size varies from 0.5-1 to 3-8 micron and could be observed as individual bacterium, diplo, and rarely streptococcus. Blackleg is a fatal disease of young cattle. It produces an acute local infection, and the resulting blood poisoning leads to rapid death. Clostridium chauvoei and, less frequently, Clostridium septicum are the most commonly responsible organisms. Vaccination is the only effective means for controlling of blackleg disease. Several kinds of vaccine are available commercially. It is 4 decades that blackleg vaccine is produced in Razi institute and because of enhanced demand of country, decision was made to improve the production procedure of this vaccine using large-scale fermenter, so the aim of this study was adaptation of Clostridium chauvoei to growth and proliferation in fermenter for preparation of a potent vaccine. Accordingly attempts were made to prepare and formulate the ingredients in order to obtain high yield of Clostridium chauvoei in culture medium by fermenter. All experiments were done in two sets: A-growth in glass bottles using conventional culture medium and B-growth in fermenter using conventional culture medium similar to A and also enriched culture medium. Results showed high yield of Clostridium chauvoei suspension in fermenter after 10 hours, using enriched culture medium (more than 1,480,000,000 organisms/ml, but no significant changes was obtained in glass bottles conditions comparing to the fermenter conditions. The safety and potency of the prepared vaccine was determined in sheep and guinea pigs according to British pharmacopoeia (veterinary with satisfactory results. Since this research has been successfully done in Razi research institute, so the mono valent inactivated blackleg vaccine, using the enriched culture medium is currently producing by fermenter and is used for immunization of cattles in Iran.

  17. Functional gene pyrosequencing and network analysis: an approach to examine the response of denitrifying bacteria to increased nitrogen supply in salt marsh sediments

    Directory of Open Access Journals (Sweden)

    JenniferL.Bowen

    2013-11-01

    Full Text Available Functional gene pyrosequencing is emerging as a useful tool to examine the diversity and abundance of microbes that facilitate key biogeochemical processes. One such process, denitrification, is of particular importance because it converts fixed nitrate (NO3- to N2 gas, which returns to the atmosphere. In N limited salt marshes, removal of NO3- prior to entering adjacent waters helps prevent eutrophication. Understanding the dynamics of salt marsh microbial denitrification is thus imperative for the maintenance of healthy coastal ecosystems. We used pyrosequencing of the nirS gene to examine the denitrifying community response to fertilization in experimentally enriched marsh plots. A key challenge in the analysis of sequence data derived from pyrosequencing is understanding whether small differences in gene sequences are ecologically meaningful. We apply a novel approach from information theory that determined that the optimal similarity level for clustering DNA sequences into OTUs, while still capturing the ecological complexity of the system, was 88% similarity. With this clustering, phylogenetic analysis yielded 6 dominant clades of denitrifiers, the largest of which, accounting for more than half of all the sequences collected, had no close cultured representatives. Of the 638 OTUs identified, only 11 were present in all plots and no single OTU was dominant. We did, however, find a large number of specialist OTUs that were present only in a single plot. The high degree of endemic OTUs, while accounting for a large proportion of the nirS diversity in the plots, were found in lower abundance than the generalist taxa. The proportion of specialist taxa increased with increasing supply of nutrients, suggesting that addition of fertilizer may create conditions that expand the niche space for denitrifying organisms and may enhance the genetic capacity for denitrification.

  18. Combined genomic and proteomic approaches identify gene clusters involved in anaerobic 2-methylnaphthalene degradation in the sulfate-reducing enrichment culture N47.

    Science.gov (United States)

    Selesi, Drazenka; Jehmlich, Nico; von Bergen, Martin; Schmidt, Frank; Rattei, Thomas; Tischler, Patrick; Lueders, Tillmann; Meckenstock, Rainer U

    2010-01-01

    The highly enriched deltaproteobacterial culture N47 anaerobically oxidizes the polycyclic aromatic hydrocarbons naphthalene and 2-methylnaphthalene, with sulfate as the electron acceptor. Combined genome sequencing and liquid chromatography-tandem mass spectrometry-based shotgun proteome analyses were performed to identify genes and proteins involved in anaerobic aromatic catabolism. Proteome analysis of 2-methylnaphthalene-grown N47 cells resulted in the identification of putative enzymes catalyzing the anaerobic conversion of 2-methylnaphthalene to 2-naphthoyl coenzyme A (2-naphthoyl-CoA), as well as the reductive ring cleavage of 2-naphthoyl-CoA, leading to the formation of acetyl-CoA and CO(2). The glycyl radical-catalyzed fumarate addition to the methyl group of 2-methylnaphthalene is catalyzed by naphthyl-2-methyl-succinate synthase (Nms), composed of alpha-, beta-, and gamma-subunits that are encoded by the genes nmsABC. Located upstream of nmsABC is nmsD, encoding the Nms-activating enzyme, which harbors the characteristic [Fe(4)S(4)] cluster sequence motifs of S-adenosylmethionine radical enzymes. The bns gene cluster, coding for enzymes involved in beta-oxidation reactions converting naphthyl-2-methyl-succinate to 2-naphthoyl-CoA, was found four intervening open reading frames further downstream. This cluster consists of eight genes (bnsABCDEFGH) corresponding to 8.1 kb, which are closely related to genes for enzymes involved in anaerobic toluene degradation within the denitrifiers "Aromatoleum aromaticum" EbN1, Azoarcus sp. strain T, and Thauera aromatica. Another contiguous DNA sequence harbors the gene for 2-naphthoyl-CoA reductase (ncr) and 16 additional genes that were found to be expressed in 2-methylnaphthalene-grown cells. These genes code for enzymes that were supposed to catalyze the dearomatization and ring cleavage reactions converting 2-naphthoyl-CoA to acetyl-CoA and CO(2). Comparative sequence analysis of the four encoding subunits (ncrABCD) showed the gene product to have the closest similarity to the Azoarcus type of benzoyl-CoA reductase. The present work provides the first insight into the genetic basis of anaerobic 2-methylnaphthalene metabolism and delivers implications for understanding contaminant degradation. PMID:19854898

  19. Fermentative bio-hydrogen production from cellulose by cow dung compost enriched cultures

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Nan-Qi; Xu, Ji-Fei; Gao, Ling-Fang; Xin, Liang; Qiu, Jie; Su, Dong-Xia [State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090 (China)

    2010-04-15

    The performance of hydrogen production from cellulose by the cow dung compost enriched continuously in defined medium containing cellulose was investigated. In the initial experiments, batch-fermentation was carried out to observe the effects of different substrate concentration conditions on the rate of cellulose-degrading, growth of bacteria and the capability of hydrogen-producing from cellulose. The result showed that the cellulose degradation decreased from 55% at 5 g/l to 22% at 30 g/l. The maximum cumulative hydrogen production and the rate of hydrogen production first increased from 828 ml/l at 5 g/l to 1251 ml/l at 10 g/l then remained constant beyond 10 g/l. The maximum hydrogen production potential, the rate of hydrogen production and the yield of hydrogen was 1525 ml/l, 33 ml/l.h, and 272 ml/g-cellulose (2.09 mol/mol-hexose) was obtained at substrate concentration 10 g/l, the hydrogen concentration in biogas was 47-50%(v/v) and there was no methane observed. During the conversion of cellulose into hydrogen, acetate and butyrate were main liquid end-products in the metabolism of hydrogen fermentation. These results proposed that cow dung compost enriched cultures were ideal microflora for hydrogen production from cellulose. (author)

  20. Selective enrichment yields robust ethene-producing dechlorinating cultures from microcosms stalled at cis-dichloroethene.

    Science.gov (United States)

    Delgado, Anca G; Kang, Dae-Wook; Nelson, Katherine G; Fajardo-Williams, Devyn; Miceli, Joseph F; Done, Hansa Y; Popat, Sudeep C; Krajmalnik-Brown, Rosa

    2014-01-01

    Dehalococcoides mccartyi strains are of particular importance for bioremediation due to their unique capability of transforming perchloroethene (PCE) and trichloroethene (TCE) to non-toxic ethene, through the intermediates cis-dichloroethene (cis-DCE) and vinyl chloride (VC). Despite the widespread environmental distribution of Dehalococcoides, biostimulation sometimes fails to promote dechlorination beyond cis-DCE. In our study, microcosms established with garden soil and mangrove sediment also stalled at cis-DCE, albeit Dehalococcoides mccartyi containing the reductive dehalogenase genes tceA, vcrA and bvcA were detected in the soil/sediment inocula. Reductive dechlorination was not promoted beyond cis-DCE, even after multiple biostimulation events with fermentable substrates and a lengthy incubation. However, transfers from microcosms stalled at cis-DCE yielded dechlorination to ethene with subsequent enrichment cultures containing up to 10(9) Dehalococcoides mccartyi cells mL(-1). Proteobacterial classes which dominated the soil/sediment communities became undetectable in the enrichments, and methanogenic activity drastically decreased after the transfers. We hypothesized that biostimulation of Dehalococcoides in the cis-DCE-stalled microcosms was impeded by other microbes present at higher abundances than Dehalococcoides and utilizing terminal electron acceptors from the soil/sediment, hence, outcompeting Dehalococcoides for H2. In support of this hypothesis, we show that garden soil and mangrove sediment microcosms bioaugmented with their respective cultures containing Dehalococcoides in high abundance were able to compete for H2 for reductive dechlorination from one biostimulation event and produced ethene with no obvious stall. Overall, our results provide an alternate explanation to consolidate conflicting observations on the ubiquity of Dehalococcoides mccartyi and occasional stalling of dechlorination at cis-DCE; thus, bringing a new perspective to better assess biological potential of different environments and to understand microbial interactions governing bioremediation. PMID:24950250

  1. Enrichment and characterization of MTBE-degrading cultures under iron and sulfate reducing conditions

    Energy Technology Data Exchange (ETDEWEB)

    Raynal, M. [Univ. Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Ingenieria; Crimi, B. [Delft Univ. of Technology (Netherlands). Dept. of Biotechnology; Pruden, A. [Virginia Tech, Blacksburg, VA (United States). Dept. of Civil and Environmental Engineering

    2010-04-15

    Methyl tert-butyl ether (MTBE) is widely used as an additive to gasoline. It has been exposed to the environment as a result of releases from underground storage tanks and pipelines. MTBE has been banned or limited in many areas of North America because of its high aqueous solubility and slow biodegradation rate. The aim of this study was to obtain highly enriched consortia capable of the anaerobic biodegradation of MTBE. Amplified 16S rDNA restriction-digest analysis (ARDRA) was used to identify the sequencing of unique 16S rRNA genes. The study examined sulfate- and iron-reducing conditions as electron acceptors in groundwater. The aqueous cultures were inoculated in 3 different growth media to examine the effect of biodegradation. Between 5 to 8 members were identified in 3 consortia. A clone was detected in cultures containing iron. Results indicated that the buildup of intermediates and the presence of sulfides inhibited biodegradation. The results may provide biomarkers to support current anaerobic MTBE biodegradation field studies. 80 refs., 1 tab., 3 figs.

  2. High yield derivation of enriched glutamatergic neurons from suspension-cultured mouse ESCs for neurotoxicology research

    Directory of Open Access Journals (Sweden)

    Hubbard Kyle S

    2012-10-01

    Full Text Available Abstract Background Recently, there has been a strong emphasis on identifying an in vitro model for neurotoxicity research that combines the biological relevance of primary neurons with the scalability, reproducibility and genetic tractability of continuous cell lines. Derived neurons should be homotypic, exhibit neuron-specific gene expression and morphology, form functioning synapses and consistently respond to neurotoxins in a fashion indistinguishable from primary neurons. However, efficient methods to produce neuronal populations that are suitable alternatives to primary neurons have not been available. Methods With the objective of developing a more facile, robust and efficient method to generate enriched glutamatergic neuronal cultures, we evaluated the neurogenic capacity of three mouse embryonic stem cell (ESC lines (R1, C57BL/6 and D3 adapted to feeder-independent suspension culture. Neurogenesis and neuronal maturation were characterized as a function of time in culture using immunological, genomic, morphological and functional metrics. The functional responses of ESNs to neurotropic toxins with distinctly different targets and mechanisms of toxicity, such as glutamate, ?-latrotoxin (LTX, and botulinum neurotoxin (BoNT, were also evaluated. Results Suspension-adapted ESCs expressed markers of pluripotency through at least 30 passages, and differentiation produced 97×106 neural progenitor cells (NPCs per 10-cm dish. Greater than 99% of embryonic stem cell-derived neurons (ESNs expressed neuron-specific markers by 96 h after plating and rapidly developed complex axodendritic arbors and appropriate compartmentalization of neurotypic proteins. Expression profiling demonstrated the presence of transcripts necessary for neuronal function and confirmed that ESN populations were predominantly glutamatergic. Furthermore, ESNs were functionally receptive to all toxins with sensitivities and responses consistent with primary neurons. Conclusions These findings demonstrate a cost-effective, scalable and flexible method to produce a highly enriched glutamatergic neuron population. The functional characterization of pathophysiological responses to neurotropic toxins and the compatibility with multi-well plating formats were used to demonstrate the suitability of ESNs as a discovery platform for molecular mechanisms of action, moderate-throughput analytical approaches and diagnostic screening. Furthermore, for the first time we demonstrate a cell-based model that is sensitive to all seven BoNT serotypes with EC50 values comparable to those reported in primary neuron populations. These data providing compelling evidence that ESNs offer a neuromimetic platform suitable for the evaluation of molecular mechanisms of neurotoxicity.

  3. Vertical Distribution of Soil Denitrifying Communities in a Wet Sclerophyll Forest under Long-Term Repeated Burning.

    Science.gov (United States)

    Liu, Xian; Chen, Chengrong; Wang, Weijin; Hughes, Jane M; Lewis, Tom; Hou, Enqing; Shen, Jupei

    2015-11-01

    Soil biogeochemical cycles are largely mediated by microorganisms, while fire significantly modifies biogeochemical cycles mainly via altering microbial community and substrate availability. Majority of studies on fire effects have focused on the surface soil; therefore, our understanding of the vertical distribution of microbial communities and the impacts of fire on nitrogen (N) dynamics in the soil profile is limited. Here, we examined the changes of soil denitrification capacity (DNC) and denitrifying communities with depth under different burning regimes, and their interaction with environmental gradients along the soil profile. Results showed that soil depth had a more pronounced impact than the burning treatment on the bacterial community size. The abundance of 16S rRNA and denitrification genes (narG, nirK, and nirS) declined exponentially with soil depth. Surprisingly, the nosZ-harboring denitrifiers were enriched in the deeper soil layers, which was likely to indicate that the nosZ-harboring denitrifiers could better adapt to the stress conditions (i.e., oxygen deficiency, nutrient limitation, etc.) than other denitrifiers. Soil nutrients, including dissolved organic carbon (DOC), total soluble N (TSN), ammonium (NH4 (+)), and nitrate (NO3 (-)), declined significantly with soil depth, which probably contributed to the vertical distribution of denitrifying communities. Soil DNC decreased significantly with soil depth, which was negligible in the depths below 20 cm. These findings have provided new insights into niche separation of the N-cycling functional guilds along the soil profile, under a varied fire disturbance regime. PMID:26066514

  4. Draft Genome Sequence of Alteromonas macleodii Strain MIT1002, Isolated from an Enrichment Culture of the Marine Cyanobacterium Prochlorococcus

    Science.gov (United States)

    Coe, Allison; Martin-Cuadrado, Ana-Belen

    2015-01-01

    Alteromonas spp. are heterotrophic gammaproteobacteria commonly found in marine environments. We present here the draft genome sequence of Alteromonas macleodii MIT1002, which was isolated from an enrichment culture of the marine cyanobacterium Prochlorococcus NATL2A. This genome contains a mixture of features previously seen only within either the “surface” or “deep” Alteromonas ecotype. PMID:26316635

  5. Members of the Family Comamonadaceae as Primary Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate)-Degrading Denitrifiers in Activated Sludge as Revealed by a Polyphasic Approach

    OpenAIRE

    Khan, Shams Tabrez; Horiba, Yoko; Yamamoto, Masamitsu; Hiraishi, Akira

    2002-01-01

    The distribution and phylogenetic affiliations of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-degrading denitrifying bacteria in activated sludge were studied by a polyphasic approach including culture-independent biomarker and molecular analyses as well as cultivation methods. A total of 23 strains of PHBV-degrading denitrifiers were isolated from activated sludges from different sewage treatment plants. 16S ribosomal DNA (rDNA) sequence comparisons showed that 20 of the isolates wer...

  6. High molecular weight dissolved organic matter enrichment selects for methylotrophs in dilution to extinction cultures.

    Science.gov (United States)

    Sosa, Oscar A; Gifford, Scott M; Repeta, Daniel J; DeLong, Edward F

    2015-12-01

    The role of bacterioplankton in the cycling of marine dissolved organic matter (DOM) is central to the carbon and energy balance in the ocean, yet there are few model organisms available to investigate the genes, metabolic pathways, and biochemical mechanisms involved in the degradation of this globally important carbon pool. To obtain microbial isolates capable of degrading semi-labile DOM for growth, we conducted dilution to extinction cultivation experiments using seawater enriched with high molecular weight (HMW) DOM. In total, 93 isolates were obtained. Amendments using HMW DOM to increase the dissolved organic carbon concentration 4x (280??M) or 10x (700??M) the ocean surface water concentrations yielded positive growth in 4-6% of replicate dilutions, whereas <1% scored positive for growth in non-DOM-amended controls. The majority (71%) of isolates displayed a distinct increase in cell yields when grown in increasing concentrations of HMW DOM. Whole-genome sequencing was used to screen the culture collection for purity and to determine the phylogenetic identity of the isolates. Eleven percent of the isolates belonged to the gammaproteobacteria including Alteromonadales (the SAR92 clade) and Vibrio. Surprisingly, 85% of isolates belonged to the methylotrophic OM43 clade of betaproteobacteria, bacteria thought to metabolically specialize in degrading C1 compounds. Growth of these isolates on methanol confirmed their methylotrophic phenotype. Our results indicate that dilution to extinction cultivation enriched with natural sources of organic substrates has a potential to reveal the previously unsuspected relationships between naturally occurring organic nutrients and the microorganisms that consume them. PMID:25978545

  7. Anaerobic alkane biodegradation by cultures enriched from oil sands tailings ponds involves multiple species capable of fumarate addition.

    Science.gov (United States)

    Tan, BoonFei; Semple, Kathleen; Foght, Julia

    2015-05-01

    A methanogenic short-chain alkane-degrading culture (SCADC) was enriched from oil sands tailings and transferred several times with a mixture of C6, C7, C8 and C10 n-alkanes as the predominant organic carbon source, plus 2-methylpentane, 3-methylpentane and methylcyclopentane as minor components. Cultures produced ?40% of the maximum theoretical methane during 18 months incubation while depleting the n-alkanes, 2-methylpentane and methylcyclopentane. Substrate depletion correlated with detection of metabolites characteristic of fumarate activation of 2-methylpentane and methylcyclopentane, but not n-alkane metabolites. During active methanogenesis with the mixed alkanes, reverse-transcription PCR confirmed the expression of functional genes (assA and bssA) associated with hydrocarbon addition to fumarate. Pyrosequencing of 16S rRNA genes amplified during active alkane degradation revealed enrichment of Clostridia (particularly Peptococcaceae) and methanogenic Archaea (Methanosaetaceae and Methanomicrobiaceae). Methanogenic cultures transferred into medium containing sulphate produced sulphide, depleted n-alkanes and produced the corresponding succinylated alkane metabolites, but were slow to degrade 2-methylpentane and methylcyclopentane; these cultures were enriched in Deltaproteobacteria rather than Clostridia. 3-Methylpentane was not degraded by any cultures. Thus, nominally methanogenic oil sands tailings harbour dynamic and versatile hydrocarbon-degrading fermentative syntrophs and sulphate reducers capable of degrading n-, iso- and cyclo-alkanes by addition to fumarate. PMID:25873461

  8. Sustained growth of explants from Mediterranean sponge Crambe crambe cultured in vitro with enriched RPMI 1640.

    Science.gov (United States)

    Garcia Camacho, F; Chileh, T; Cerón García, M C; Sanchez Mirón, A; Belarbi, E H; Contreras Gómez, A; Molina Grima, E

    2006-01-01

    Marine sponges are potential sources of many unique metabolites, including cytotoxic and anticancer compounds. Natural sponge populations are insufficient or inaccessible for producing commercial quantities of metabolites of interest. It is commonly accepted that tissue (fragments, explants, and primmorphs) and in vitro cell cultivation show great potential. However, there is little knowledge of the nutritional requirements of marine sponges to carry out efficient and sustained in vitro culture and progress has been slow. In marine invertebrate fila many unsuccessful attempts have been made with in vitro cultures using typical commercial animal cell media based on sources of dissolved organic carbon (DOC) (e.g., DMEM, RPMI, M199, L-15, etc.). One of the reasons for this failure is the use of hardly identifiable growth promoters, based on terrestrial animal sera. An alternative is the use of extracts from marine animals, since they may contain nutrients necessary for growth. In this work we have cultivated in vitro explants of the encrusting marine sponge Crambe crambe. It is one of the most abundant sponges on the Mediterranean coastline and also possesses an array of potentially active metabolites (crambines and crambescidins). Initially a new approach was developed in order to show consumption of DOC by explants. Thus, different initial DOC concentrations (300, 400, 700 and 1200 mg DOC L(-1)) were assayed. Consumption was evident in all four assays and was more marked in the first 6 h. The DOC assimilation data were adjusted to an empirical model widely used for uptake kinetics of organic dissolved compounds in marine invertebrates. Second, a protocol was established to cultivate explants in vitro. Different medium formulations based on RPMI 1640 commercial medium enriched with amino acids and inorganic salts to emulate seawater salinity were assayed. The enrichment of this medium with an Octopus aqueous extract in the proportions of 10% and 20% (v/v) resulted in an evident sustained long-term growth of C. crambe explants. This growth enhancement produced high metabolic activity in the explants, as is confirmed by the high ammonium and lactate content in the medium a few days after its renewal and by the consumption of glucose. The lactate accumulation increased with the size and age of explants. Prior to these experiments, we successfully developed a robust new alternative method, based on digital image treatment, for accurate determination of the explant apparent volume as growth measure. PMID:16739962

  9. Identity and Substrate Specificity of Reductive Dehalogenases Expressed in Dehalococcoides-Containing Enrichment Cultures Maintained on Different Chlorinated Ethenes.

    Science.gov (United States)

    Liang, Xiaoming; Molenda, Olivia; Tang, Shuiquan; Edwards, Elizabeth A

    2015-07-01

    Many reductive dehalogenases (RDases) have been identified in organohalide-respiring microorganisms, and yet their substrates, specific activities, and conditions for expression are not well understood. We tested whether RDase expression varied depending on the substrate-exposure history of reductive dechlorinating communities. For this purpose, we used the enrichment culture KB-1 maintained on trichloroethene (TCE), as well as subcultures maintained on the intermediates cis-dichloroethene (cDCE) and vinyl chloride (VC). KB-1 contains a TCE-to-cDCE dechlorinating Geobacter and several Dehalococcoides strains that together harbor many of the known chloroethene reductases. Expressed RDases were identified using blue native polyacrylamide gel electrophoresis, enzyme assays in gel slices, and peptide sequencing. As anticipated but never previously quantified, the RDase from Geobacter was only detected transiently at the beginning of TCE dechlorination. The Dehalococcoides RDase VcrA and smaller amounts of TceA were expressed in the parent KB-1 culture during complete dechlorination of TCE to ethene regardless of time point or amended substrate. The Dehalococcoides RDase BvcA was only detected in enrichments maintained on cDCE as growth substrates, in roughly equal abundance to VcrA. Only VcrA was detected in subcultures enriched on VC. Enzyme assays revealed that 1,1-DCE, a substrate not used for culture enrichment, afforded the highest specific activity. trans-DCE was substantially dechlorinated only by extracts from cDCE enrichments expressing BvcA. RDase gene distribution indicated enrichment of different strains of Dehalococcoides as a function of electron acceptor TCE, cDCE, or VC. Each chloroethene reductase has distinct substrate preferences leading to strain selection in mixed communities. PMID:25934625

  10. Diversity of reductive dehalogenase genes from environmental samples and enrichment cultures identified with degenerate primer PCR screens.

    Directory of Open Access Journals (Sweden)

    LauraAudreyHug

    2013-11-01

    Full Text Available Reductive dehalogenases are the critical enzymes for anaerobic organohalide respiration, a microbial metabolic process that has been harnessed for bioremediation efforts to resolve chlorinated solvent contamination in groundwater and is implicated in the global halogen cycle. Reductive dehalogenase sequence diversity is informative for the dechlorination potential of the site or enrichment culture. A suite of degenerate PCR primers targeting a comprehensive curated set of reductive dehalogenase genes was designed and applied to twelve DNA samples extracted from contaminated and pristine sites, as well as six enrichment cultures capable of reducing chlorinated compounds to non-toxic end-products. The amplified gene products from four environmental sites and two enrichment cultures were sequenced using Illumina HiSeq, and the reductive dehalogenase complement of each sample determined. The results indicate that the diversity of the reductive dehalogenase gene family is much deeper than is currently accounted for: one-third of the translated proteins have less than 70% pairwise amino acid identity to database sequences. Approximately 60% of the sequenced reductive dehalogenase genes were broadly distributed, being identified in four or more samples, and often in previously sequenced genomes as well. In contrast, 17% of the sequenced reductive dehalogenases were unique, present in only a single sample and bearing less than 90% pairwise amino acid identity to any previously identified proteins. Many of the broadly distributed reductive dehalogenases are uncharacterized in terms of their substrate specificity, making these intriguing targets for further biochemical experimentation. Finally, comparison of samples from a contaminated site and an enrichment culture derived from the same site eight years prior allowed examination of the effect of the enrichment process.

  11. Platelet-activating factor increases prostaglandin E(2) release from astrocyte-enriched cortical cell cultures.

    Science.gov (United States)

    Teather, Lisa A; Lee, Robert K K; Wurtman, Richard J

    2002-08-01

    The phospholipid mediator platelet-activating factor (PAF) increased the release of prostaglandin E(2) (PGE(2)) from astrocyte-enriched cortical cell cultures in a concentration- and time-dependent manner. The nonhydrolyzable PAF analog methylcarbamyl-PAF (mc-PAF), the PAF intermediate lyso-PAF, and arachidonic acid (AA) also produced this effect. In contrast, phosphatidlycholine (PC) and lyso-PC, lipids that are structurally similar to PAF and lyso-PAF, had no effect on PGE(2) production, suggesting that PAF-induced PGE(2) release is not the consequence of nonspecific phospholipid-induced membrane perturbation. Antagonism of intracellular PAF binding sites completely abolished the ability of mc-PAF and lyso-PAF to mobilize PGE(2,) and attenuated the AA effect. Antagonism of the G-protein-coupled PAF receptor in plasma membranes had no significant effect on mc-PAF, lyso-PAF or AA-induced PGE(2) release. Based on the present findings, we hypothesize that intracellular PAF is a physiologic stimulus of PGE(2) production in astrocytes. PMID:12133598

  12. Distribution of nitrogenous nutrients and denitrifiers strains in estuarine sediment profiles of the Tanshui River, northern Taiwan

    Science.gov (United States)

    Fan, L. F.; Shieh, W. Y.; Wu, W. F.; Chen, C.-P.

    2006-09-01

    Chemical profiles of both oxidized (nitrate and sulfate) and reduced (ammonium, sulfide, acid-volatile sulfide [AVS], and pyrite) materials and the corresponding distribution of denitrifier microbial communities were measured at low tide in sediments at Guandu in the estuary of the Tanshui River, northern Taiwan in August 2002. Denitrifier strains were isolated for physiological and phylogenic analyses. Based on the distribution of nitrogenous compounds and denitrifier abundances, the vertical profile of Guandu sediments could be separated into four layers: a mixed layer (the top 1 cm of depth, respectively containing 0.82-2.37 and 535.9-475.0 ?M of nitrate and ammonium), a nitrate-concentrated layer (1-5 cm in depth, 2.37-0.53 and 475.0-1192.1 ?M, respectively), a denitrifier-aggregation layer (5-7 cm in depth, 0.53-0.72 and 1192.1-1430.1 ?M, respectively), and an ammonium-enriched layer (7-12 cm in depth, 0.72-0.78 and 1430.1-2196.6 ?M, respectively). Denitrifier strains were detected in all layers except for the mixed layer. A variety of metabolic processes by these strains may occur in different layers. Bacillus jeotgali-, Bacillus sphaericus-, and Bacillus firmus-related strains isolated from the nitrate-concentrated layer may be involved in the nitrification-denitrification coupling process due to the relatively low nitrate concentrations (maximum = 2.37 ?M), and may contribute to denitrification not nitrification. Bacillus bataviensis- and B. jeotgali-related strains isolated from the denitrifier-aggregation layer comprised the predominant denitrifier population (3.64 × 10 4 cells/g of denitrifier abundance). They possess the ability of dissimilatory nitrate reduction to ammonium (DNRA). Bacillus jeotgali-related strains and two newly identified strains of GD0705 and GD0706 isolated from the ammonium-enriched layer possibly use fermentative processes as the main metabolic pathway instead of denitrification when nitrate is scarce, and this further supports the high ammonium concentrations (up to 2.20 mM) found in the Guandu sediments. In addition, spore formation also enhances the chance of survival of these strains in the face with such a nitrate-deficient environment.

  13. Passive markers as a low-cost method of enriching cultural visits on user’s demand

    Directory of Open Access Journals (Sweden)

    Anestis Koutsoudis

    2014-01-01

    Full Text Available The idea of enriching a cultural heritage visitor’s experience by employing mobile devices such as smartphones and tablets is an active research domain. This is mainly due to the worldwide user penetration of such devices along with their continuous hardware performance enhancement. This work presents the experience and feedback gained by one year of operation of an experimental information system that aims in enhancing the experience of a visitor on his/her demand. The evaluated system is based on the use case-scenario where the a mobile device is used to capture and decode passive markers (such as QR-codes that are located on facades of selected important buildings in the old town of Xanthi, Greece, in order to enrich the visitor’s experience through a broad context of historical and architectural information delivered over the Web.   Keywords: On-demand information, Passive marker, QR-code, Smartphone, Visit enrichment.

  14. Bacterial community analysis in chlorpyrifos enrichment cultures via DGGE and use of bacterial consortium for CP biodegradation.

    Science.gov (United States)

    Akbar, Shamsa; Sultan, Sikander; Kertesz, Michael

    2014-10-01

    The organophosphate pesticide chlorpyrifos (CP) has been used extensively since the 1960s for insect control. However, its toxic effects on mammals and persistence in environment necessitate its removal from contaminated sites, biodegradation studies of CP-degrading microbes are therefore of immense importance. Samples from a Pakistani agricultural soil with an extensive history of CP application were used to prepare enrichment cultures using CP as sole carbon source for bacterial community analysis and isolation of CP metabolizing bacteria. Bacterial community analysis (denaturing gradient gel electrophoresis) revealed that the dominant genera enriched under these conditions were Pseudomonas, Acinetobacter and Stenotrophomonas, along with lower numbers of Sphingomonas, Agrobacterium and Burkholderia. Furthermore, it revealed that members of Bacteroidetes, Firmicutes, ?- and ?-Proteobacteria and Actinobacteria were present at initial steps of enrichment whereas ?-Proteobacteria appeared in later steps and only Proteobacteria were selected by enrichment culturing. However, when CP-degrading strains were isolated from this enrichment culture, the most active organisms were strains of Acinetobacter calcoaceticus, Pseudomonas mendocina and Pseudomonas aeruginosa. These strains degraded 6-7.4 mg L(-1) day(-1) of CP when cultivated in mineral medium, while the consortium of all four strains degraded 9.2 mg L(-1) day(-1) of CP (100 mg L(-1)). Addition of glucose as an additional C source increased the degradation capacity by 8-14 %. After inoculation of contaminated soil with CP (200 mg kg(-1)) disappearance rates were 3.83-4.30 mg kg(-1) day(-1) for individual strains and 4.76 mg kg(-1) day(-1) for the consortium. These results indicate that these organisms are involved in the degradation of CP in soil and represent valuable candidates for in situ bioremediation of contaminated soils and waters. PMID:25008559

  15. Preparation of Glycerol-Enriched Yeast Culture and Its Effect on Blood Metabolites and Ruminal Fermentation in Goats

    OpenAIRE

    Ye, Gengping; Zhu, Yongxing; Liu, Jin; Chen, Xingxiang; Huang, Kehe

    2014-01-01

    The aim of this study was to isolate a glycerol-producing yeast strain from nature to prepare glycerol-enriched yeast culture (GY), and preliminarily evaluate the effects of GY on blood metabolites and ruminal fermentation in goats. During the trial, six isolates were isolated from unprocessed honey, and only two isolates with higher glycerol yield were identified by analysis of 26S ribosomal DNA sequences. One of the two isolates was identified as Saccharomyces cerevisiae, a direct-fed micro...

  16. Anaerobic Oxidation of n-Dodecane by an Addition Reaction in a Sulfate-Reducing Bacterial Enrichment Culture

    OpenAIRE

    Kropp, Kevin G.; Davidova, Irene A.; Suflita, Joseph M.

    2000-01-01

    We identified trace metabolites produced during the anaerobic biodegradation of H26- and D26-n-dodecane by an enrichment culture that mineralizes these compounds in a sulfate-dependent fashion. The metabolites are dodecylsuccinic acids that, in the case of the perdeuterated substrate, retain all of the deuterium atoms. The deuterium retention and the gas chromatography-mass spectrometry fragmentation patterns of the derivatized metabolites suggest that they are formed by C—H or C—D addition a...

  17. Atrazine biodegradation efficiency, metabolite detection, and trzD gene expression by enrichment bacterial cultures from agricultural soil

    OpenAIRE

    Solomon, Robinson David Jebakumar; Kumar, Amit; Satheeja Santhi, Velayudhan

    2013-01-01

    Atrazine is a selective herbicide used in agricultural fields to control the emergence of broadleaf and grassy weeds. The persistence of this herbicide is influenced by the metabolic action of habituated native microorganisms. This study provides information on the occurrence of atrazine mineralizing bacterial strains with faster metabolizing ability. The enrichment cultures were tested for the biodegradation of atrazine by high-performance liquid chromatography (HPLC) and mass spectrometry. ...

  18. Assessing the influence of CH4 concentration during culture enrichment on the biodegradation kinetics and population structure.

    Science.gov (United States)

    López, Juan C; Quijano, Guillermo; Pérez, Rebeca; Muñoz, Raúl

    2014-12-15

    Methanotrophic communities were enriched in three stirred tank reactors continuously supplied with CH4-laden air at 20, 2 and 0.2 gCH4 m(-3) in order to evaluate the influence of CH4 concentration on the biodegradation kinetics, population structure and potential polyhydroxyalkanoate production under sequential nitrogen limitations. The population structure of the enriched cultures, dominated by type I methanotrophs, was influenced by CH4 concentration. No significant correlation between CH4 concentration and the maximum specific degradation rate (qmax) or the half-saturation constant (KS) was recorded, microorganisms enriched at 2 gCH4 m(-3) presenting the highest qmax and those enriched at 20 and 0.2 gCH4 m(-3) exhibiting the lowest KS. Maximum polyhydroxybutyrate (PHB) contents of 1.0% and 12.6% (w/w) were achieved at 20 and 2 g CH4 m(-3), respectively. Polyhydroxyvalerate (PHV) was also detected at PHV:PHB ratios of up to 12:1 and 4:1 in the communities enriched at 20 and 0.2 gCH4 m(-3), respectively. PMID:25169644

  19. PCR amplification of Bartonella koehlerae from human blood and enrichment blood cultures

    Directory of Open Access Journals (Sweden)

    Breitschwerdt Edward B

    2010-08-01

    Full Text Available Abstract Background Cats appear to be the primary reservoir host for Bartonella koehlerae, an alpha Proteobacteria that is most likely transmitted among cat populations by fleas (Ctenocephalides felis. Bartonella koehlerae has caused endocarditis in a dog and in one human patient from Israel, but other clinically relevant reports involving this bacterium are lacking. Despite publication of numerous, worldwide epidemiological studies designed to determine the prevalence of Bartonella spp. bacteremia in cats, B. koehlerae has never been isolated using conventional blood agar plates. To date, successful isolation of B. koehlerae from cats and from the one human endocarditis patient has consistently required the use of chocolate agar plates. Results In this study, Bartonella koehlerae bacteremia was documented in eight immunocompetent patients by PCR amplification and DNA sequencing, either prior to or after enrichment blood culture using Bartonella alpha Proteobacteria growth medium. Presenting symptoms most often included fatigue, insomnia, joint pain, headache, memory loss, and muscle pain. Four patients were also infected with Bartonella vinsonii subsp. berkhoffii genotype II. After molecular documentation of B. koehlerae infection in these patients, a serological test was developed and serum samples were tested retrospectively. Bartonella koehlerae antibodies were not detected (titers B. koehlerae antibody titers of 1:64 or greater. Conclusions Although biased by a study population consisting of individuals with extensive arthropod and animal exposure, the results of this study suggest that B. koehlerae bacteremia is more common in immunocompetent people than has been previously suspected. Future studies should more thoroughly define modes of transmission and risk factors for acquiring infection with B. koehlerae. In addition, studies are needed to determine if B. koehlerae is a cause or cofactor in the development of arthritis, peripheral neuropathies or tachyarrhythmias in patients.

  20. Degradation of polycyclic aromatic hydrocarbons by microbial consortia enriched from three soils using two different culture media

    International Nuclear Information System (INIS)

    A consortium composed of many different bacterial species is required to efficiently degrade polycyclic aromatic hydrocarbons (PAH) in oil-contaminated soil. We obtained six PAH-degrading microbial consortia from three oil-contaminated soils using two different isolation culture media. Denaturing gradient gel electrophoresis (DGGE) and sequence analyses of amplified 16s rRNA genes confirmed the bacterial community was greatly affected by both the culture medium and the soil from which the consortia were enriched. Three bacterial consortia enriched using malt yeast extract (MYE) medium showed higher degradation rates of PAHs than consortia enriched using Luria broth (LB) medium. Consortia obtained from a soil and then added back to that same soil was more effective in degrading PAHs than adding, to the same soil, consortia isolated from other, unrelated soils. This suggests that inoculum used for bioremediation should be from the same, or very similar nearby soils, as the soil that is actually being bioremediated. -- Highlights: •Six PAH-degrading microbial consortia were isolated from three oil-contaminated soils. •The bacterial community by 16s rRNA genes was affected by culture media and source soil. •Inoculum should be from the same or similar soil as the soil being bioremediated. -- Bioremediation of oil-contaminated soils was most effective when using inoculum of microbial consortia from the same or similar soil as the soil being bioremediated

  1. Fermentative degradation of nonionic surfactants and polyethylene glycol by enrichment cultures and by pure cultures of homoacetogenic and propionate-forming bacteria

    OpenAIRE

    Wagener, Stefan; Schink, Bernhard

    1988-01-01

    Linear alkyl ethoxylates (polyethylene glycol alkyl ethers) were fermented completely to methane and CO2 in enrichment cultures inoculated with anoxic sewage sludge. Long-chain fatty acids were released as intermediates. No degradation was found with polypropylene glycol and polypropylene glycol-containing surfactants. Two types of primary ethoxylate-degrading bacteria were isolated and characterized. Both degraded polyethylene glycols with molecular weights of 1,000 completely. Strain KoB35 ...

  2. Building Learning Communities for Research Collaboration and Cross-Cultural Enrichment in Science Education

    Science.gov (United States)

    Sparrow, E. B.

    2003-12-01

    The GLOBE program has provided opportunities for environmental science research and education collaborations among scientists, teachers and K-12 students, and for cross-cultural enrichment nationally and abroad. In Alaska, GLOBE has also provided funding leverage in some cases, and a base for several other science education programs that share a common goal of increasing student interest, understanding, process skills and achievement in science, through involvement in ongoing research investigations. These programs that use GLOBE methodologies (standardized scientific measurements and learning activities developed by scientists and educators) are: Global Change Education Using Western Science and Native Knowledge also known as "Observing Locally, Connecting Globally" (OLCG); Alaska Earth System Science Education Alliance: Improving Understanding of Climate Variability and Its Relevance to Rural Alaska; Schoolyard Long Term Ecological Research; Alaska Rural Research Partnership; Alaska Partnership for Teacher Enhancement; Alaska Lake Ice and Snow Observatory Network; Alaska Boreal Forest Council Education Outreach; Calypso Farm and Ecology Center; Environmental Education Outreach; and also GLOBE Arctic POPs (persistent organic pollutants) a program that involves countries in the circumpolar North. The University of Alaska GLOBE Partnership has collaborated with the BLM Campbell Creek Science Center Globe Partnership in facilitating GLOBE Training Workshops and providing teacher support. GLOBE's extensive website including data entry, archive, analysis and visualization capabilities; GLOBE Teacher Guide, videos and other materials provided; excellent GLOBE science research and education staff, training support office, GLOBE help desk, alignment of GLOBE curriculum with national science education standards and GLOBE certification of teachers trained on even just one GLOBE investigation, have made it easier to implement GLOBE in the classroom. Using GLOBE, whole classes of students have engaged in and contributed data to science investigations. In Alaska, classes and individual students have conducted their own inquiry studies and have successfully presented their investigations and competed at science fairs and statewide high school science symposium and international conferences. Two students presented their research investigations at the GLOBE Learning Expedition in Croatia and four students presented their study at the GLOBE Arctic POPs Conference in Sweden. These students increased not only their understanding and knowledge of science but also in appreciation of people in other countries and their cultures. Friendships have also bloomed. The learning community in Alaska has expanded to include family and community members including Native elders (using OLCG), teachers, scientists and students from other countries. The following challenges remain: 1) getting funds to be able to provide GLOBE equipment and continuous support to GLOBE teachers and students throughout the year, 2) reaching teachers and students in remote areas, 3) rapid teacher turn-over rate in rural areas, 4) using inquiry-based pedagogies during GLOBE professional development workshops including the opportunity for teacher participants to conduct their own inquiries during the workshop, 5) time, school curriculum and national education requirement constraints, 6) involving school administrators, and more local scientists and community members, and 7) providing culturally relevant and responsive science education programs and life-long learning communities.

  3. Addition of novobiocin in pre-enrichment step can improve Salmonella culture protocol of modified semisolid Rappaport-Vassiliadis

    DEFF Research Database (Denmark)

    Jensen, Annette Nygaard; SØrensen, Gitte

    2003-01-01

    The aim was to investigate the effect of addition of Novobiocin to the non-selective buffered peptone water (BPW) for pre-enrichment of Salmonella in connection with plating on modified semisolid Rappaport-Vassiliadis (MSRV). In a semi-quantitative study, the level of Salmonella following pre-enrichment of 32 presumably naturally contaminated swine fecal samples were assessed for BPW with and without addition of Novobiocin (22 mug/ml). In another experiment, a total of 400 swine fecal samples were screened for the presence of Salmonella spp., in order to compare the performance of the nonselective pre-enrichment broth with BPW made semi-selective by addition of Novobiocin. The semi-quantitative assessment of the Salmonella level showed that addition of Novobiocin in the pre-enrichment step on average increased the level of Salmonella 1.2 log dilution steps. When growth was scored at five levels, 90 samples opposed to 50 yielded a strong positive reading (+++) when Novobiocin was applied. Growth was on average0.3 scores higher when pre-enriched with Novobiocin. The difference in growth score medians of the two methods was highly significant (Sign test; p <0.001). Despite the increased sensitivity, 13 culture-positive samples were missed when using the Novobiocin-containing BPW. In conclusion, a simple addition of Novobiocin in the BPW pre-enrichment step of fecal samples may facilitate reading and thereby detection of Salmonella on MSRV. The increase of Salmonella in the semi-quantitative study may be caused by a reduction in the number of competitive microorganisms.

  4. Site-specific variability in BTEX biodegradation under denitrifying conditions

    International Nuclear Information System (INIS)

    Laboratory microcosm experiments were conducted to evaluate the feasibility of benzene, toluene, ethylbenzene, m-xylene, and o-xylene (BTEX) biodegradation under denitrifying conditions. Nine different sources of inocula, including contaminated and uncontaminated soil cores from four different sites and activated sludge, were used to establish microcosms. BTEX was not degraded under denitrifying conditions in microcosms inoculated with aquifer material from Rocky Point and Traverse City. However, rapid depletion of glucose under denitrifying conditions was observed in microcosms containing Rocky Point aquifer material. TEX degradation was observed in microcosms containing Rocky Point aquifer material. TEX degradation was observed in microcosms containing aquifer material from Fort Bragg and Sleeping Bear Dunes and sewage sludge. Benzene was recalcitrant in all microcosms tested. The degradation of o-xylene ceased after toluene, ethylbenzene, and m-xylene were depleted in the Fort Bragg and sludge microcosms, but o-xylene continued to degrade in microcosms with contaminated Sleeping Bear Dunes soil. The most probable number (MPN) of denitrifiers in these nine different inocula were measured using a microtiter technique. There was no correlation between the MPN of denitrifiers and the TEX degradation rate under denitrifying conditions. Experimental results indicate that the degradation sequence and TEX degradation rate under denitrifying conditions may differ among sites. Results also indicate that denitrification alone may not be a suitable bioremediation technology for gasoline-contaminated aquifers because of the inability of denitrifiers to degrade benzene

  5. Enrichment strategy to select functional consortium from mixed cultures: Consortium from rumen liquor for simultaneous cellulose degradation and hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Aijie; Ren, Nanqi [State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); School of Environmental and Municipal Engineering, Harbin Institute of Technology, Harbin 150090 (China); Gao, Lingfang; Xu, Jifei; Liu, Chong; Lee, Duu-Jong [School of Environmental and Municipal Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2010-12-15

    Strain isolation using conventional roll tube/plating technique is time consuming and is able to culture in vitro only a small fraction of existing microbes in a natural microflora. This paper proposed a simple and rapid method to select the as-simple-as-possible biological consortium by serially diluting the original mixed culture. The diluted which remains, while the one diluted in serial loses the target function, is defined as the functional consortium of the original mixed culture. Since the microbial structure and the reaction pathway incorporated with the functional consortium is much simpler than its original mother liquor, detailed analysis on the strain interaction is possible without the risk of losing key functional strains as often caused from conventional isolation method. The rumen liquor that can degrade cellulose and produce hydrogen is used as a demonstration example. A ''rumen cellulose-degrading bacterial consortium'' (RCBC) was identified using the proposed enrichment strategy. (author)

  6. Effects of Temperature on Denitrifying Growth and Nitrate Reduction End Products of Comamonas testosteroni Isolated from Estuarine Sediment

    OpenAIRE

    IMAN RUSMANA

    2007-01-01

    Predictions of seasonal changes in N2O emission that occur in natural estuaries are important to anticipate the future implications of global warming. This study showed the effect of temperature on denitrifying growth and nitrate reduction end product of Comamonas testoteroni isolated from estuarine sediment using both batch and continuous cultures. The ?max values of Comamonas testosteroni grown in anaerobic batch culture were increased with increasing temperature, and the highest ?max was f...

  7. A New Protocol to Detect Multiple Foodborne Pathogens with PCR Dipstick DNA Chromatography after a Six-Hour Enrichment Culture in a Broad-Range Food Pathogen Enrichment Broth

    OpenAIRE

    Masahiro Hayashi; Tatsuya Natori; Sayoko Kubota-Hayashi; Machiko Miyata; Kiyofumi Ohkusu; Keiko Kawamoto; Hisao Kurazono; Souichi Makino; Takayuki Ezaki

    2013-01-01

    A quick foodborne pathogen screening method after six-hour enrichment culture with a broad-range food pathogen enrichment broth is described. Pathogenic factors of Salmonella enterica, Shigella spp., enteroinvasive Escherichia coli, and enterohemorrhagic E. coli are amplified with a cocktail primer and rapid polymerase chain reaction (PCR), which finishes amplification in 30?min. The PCR amplicon was differentiated with a dipstick DNA chromatography assay in 5–10?min. Starting from a four- to...

  8. Molecular Detection of Culture-Confirmed Bacterial Bloodstream Infections with Limited Enrichment Time

    OpenAIRE

    Moore, Miranda S; McCann, Chase D.; Jordan, Jeanne A

    2013-01-01

    Conventional blood culturing using automated instrumentation with phenotypic identification requires a significant amount of time to generate results. This study investigated the speed and accuracy of results generated using PCR and pyrosequencing compared to the time required to obtain Gram stain results and final culture identification for cases of culture-confirmed bloodstream infections. Research and physician-ordered blood cultures were drawn concurrently. Aliquots of the incubating rese...

  9. Feasibility study of an alkaline-based chemical treatment for the purification of polyhydroxybutyrate produced by a mixed enriched culture.

    Science.gov (United States)

    Jiang, Yang; Mikova, Gizela; Kleerebezem, Robbert; van der Wielen, Luuk Am; Cuellar, Maria C

    2015-12-01

    This study focused on investigating the feasibility of purifying polyhydroxybutyrate (PHB) from mixed culture biomass by alkaline-based chemical treatment. The PHB-containing biomass was enriched on acetate under non-sterile conditions. Alkaline treatment (0.2 M NaOH) together with surfactant SDS (0.2 w/v% SDS) could reach 99% purity, with more than 90% recovery. The lost PHB could be mostly attributed to PHB hydrolysis during the alkaline treatment. PHB hydrolysis could be moderated by increasing the crystallinity of the PHB granules, for example, by biomass pretreatment (e.g. freezing or lyophilization) or by effective cell lysis (e.g. adjusting alkali concentration). The suitability of the purified PHB by alkaline treatment for polymer applications was evaluated by molecular weight and thermal stability. A solvent based purification method was also performed for comparison purposes. As result, PHB produced by mixed enriched cultures was found suitable for thermoplastic applications when purified by the solvent method. While the alkaline method resulted in purity, recovery yield and molecular weight comparable to values reported in literature for PHB produced by pure cultures, it was found unsuitable for thermoplastic applications. Given the potential low cost and favorable environmental impact of this method, it is expected that PHB purified by alkaline method may be suitable for other non-thermal polymer applications, and as a platform chemical. PMID:25642402

  10. An agarose gel-based neurosphere culture system leads to enrichment of neuronal lineage cells in vitro.

    Science.gov (United States)

    Park, Kyuhee; Nam, Yeonju; Choi, Yongmun

    2015-05-01

    Stem cell-based therapy holds great potential especially for neurological disorders. However, clinical applications await further understanding of many aspects of stem cell differentiation and development of technology enabling manipulation of stem cells into desired cell types in the central nervous system. Here, we developed a new method that leads to enrichment of neuronal lineage cells in neural stem cell cultures. The protocol involves cultivation of primary cells derived from the forebrains of rat E18 embryos above a layer of nonadhesive hard agarose gel in the form of neurospheres. In contrast to the neurospheres that were cultured above an anti-adhesive hydrogel layer, the primary cells that were cultured above a layer of agarose gel preferentially differentiated into ?-III tubulin-positive neurons when allowed to undergo differentiation in vitro.In an effort to investigate the mechanism behind this observation, we found that the gene expression of a vertebrate neuronal determination gene (neurogenin1) was enhanced in the neurospheres that proliferated above a layer of agarose gel as compared with the control, and the gene expression level of neurogenin1 was quite well correlated with the rigidity of agarose gel. These results indicate that agarose gel can contribute, at least in part, to enrich neuronal progenitors and immature postmitotic neurons during neurosphere formation and may provide additional information to establish efficient protocols for the neural stem cell-based study. PMID:25539864

  11. Growth of in vitro Oncidesa plantlets cultured under cold cathode fluorescent lamps with super-elevated CO2 enrichment

    OpenAIRE

    Norikane, Atsushi; Jaime A. TEIXEIRA DA SILVA; Tanaka, Michio

    2013-01-01

    How can one increase the biomass of plants, particularly orchids, in an effective way? Photoautotrophic micropropagation is an effective means of increasing the biomass of Oncidesa orchids. Using 10,000 µmol mol?1 CO2 and a photosynthetic photon flux density of 60 µmol m?2 s?1, the number of leaves and roots and shoot and root fresh and dry weights could be considerably increased, but only when cultured on Kyoto medium rather than Vacin and Went medium. Super-elevated CO2 enrichment and growt...

  12. Macrofaunal Impact on the Denitrifying Bacterial Community in Freshwater Sediment

    DEFF Research Database (Denmark)

    Poulsen, Morten; Stief, Peter

    Sediment-dwelling macroinvertebrates alter their habitat by transporting oxic water into the sediment and enriching it for organic matter, thereby affecting microbial processes in the sediment. Here we report that burrowing macroinvertebrates can also have a pronounced effect on microbial diversity, with nitrate-reducing and denitrifying bacteria as examples. The diversity of these functional groups was compared in sediment microcosms with and without Chironomus plumosus larvae, using the genes encoding nitrate reductase (narG) and nitrous oxide reductase (nosZ) as functional markers. The estimated phylotype richness of narG increased from 68 in sediment without larvae to 170 in sediment with larvae. Part of this increase in narG diversity could be explained by metabolic activation of certain nitrate-reducing bacteria in the gut of C. plumosus, since 18.3 % of the additional phylotypes were found actively expressed in the gut contents of C. plumosus. The remaining increase may be due to the creationof a (on the microscale) more structured habitat by larval activities like burrow construction, bioturbation, and water pumping, possibly combined with a general activation of microbes by enriching the sediment with partly degraded organic material excreted by the larvae. In contrast to narG, nosZ phylotype richness was unaffected by the presence of chironomid larvae, and very few nosZ phylotypes were actively expressed in the larvae gut. Our results suggest that burrowing macroinvertebrates affect the microbial diversity in sediments, both indirectly by their behaviour and directly by activating certain functional groups of microorganisms passing through their gut.

  13. Embedded Voices: Building a Non-Learning Culture within a Learning Enrichment Programme

    Science.gov (United States)

    Hymer, Barry; Watkins, Chris; Dawson, Elizabeth; Buxton, Ruth

    2015-01-01

    The researchers examined transcripts of comments made and dialogues engaged in by children, teachers and student teaching assistants during a 10-week enrichment programme for gifted and talented children aged 7-9 years. Attempts were made to match these utterances with the programme's aims and aspirations as expressed in a promotional…

  14. Passport to Cultural Enrichment: The Peace Corps World Wise Schools Experience

    Science.gov (United States)

    Carano, Kenneth T.

    2009-01-01

    In recent studies, youths in the United States have demonstrated a remarkable lack of cultural literacy. As the world is becoming increasingly interconnected, it is imperative that students enhance their understanding of other cultures. A classroom correspondence match with a Peace Corps volunteer through the Coverdell Peace Corps World Wise…

  15. Evaluation of liquid and solid culture media for the recovery and enrichment of Burkholderia cenocepacia from distilled water.

    Science.gov (United States)

    Ahn, Youngbeom; Kim, Jeong Myeong; Ahn, Hyeri; Lee, Yong-Jin; LiPuma, John J; Hussong, David; Cerniglia, Carl E

    2014-07-01

    Burkholderia cepacia complex (BCC) presence has been the cause of recalls of both sterile and non-sterile pharmaceutical products since these opportunistic pathogens have been implicated to cause infections to susceptible individuals. BCC are ubiquitous in nature, but in pharmaceutical settings the most common source is contaminated water systems. Some strains of BCC, previously described as Pseudomonas cepacia, were not readily detected by standard culture methods. We have explored different strategies to recover and enrich Burkholderia cenocepacia previously cultured in distilled water for 40 days. Enrichment media of varied nutrient concentrations and composition were used, including modified Tryptic Soy Agar or Broth (TSA or TSB), Reasoner's 2nd Agar or Broth (R2A or R2AB), Brain-Heart Infusion Broth (BHIB), Mueller-Hinton Broth (MHB), and Ashdown's (ASH) medium. Of the various broth media tested, cell growth was significantly greater in TSB and R2AB than in BHIB, MHB, or ASH broth. TSB and R2AB were also compared for their recovery efficiency. Generally, there was no significant difference between the numbers of B. cenocepacia grown on 15 differently modified TSA and five modified R2A solid media. Overall, however, diluted TSA and TSB media, and R2A and R2AB showed better recovery efficiency than TSA and TSB for inocula containing small numbers of cells. All strains persisted in distilled water for 40 days. Broth media were more effective than solid media for recovery of B. cenocepacia from distilled water. These results may assist in improving detection assays with recovery and enrichment strategies to maximize recovery of these fastidious organisms. PMID:24756630

  16. Applicability of a Lactobacillus amylovorus strain as co-culture for natural folate bio-enrichment of fermented milk.

    Science.gov (United States)

    Laiño, Jonathan Emiliano; Juarez del Valle, Marianela; Savoy de Giori, Graciela; LeBlanc, Jean Guy Joseph

    2014-11-17

    The ability of 55 strains from different Lactobacillus species to produce folate was investigated. In order to evaluate folic acid productivity, lactobacilli were cultivated in the folate-free culture medium (FACM). Most of the tested strains needed folate for growth. The production and the extent of vitamin accumulation were distinctive features of individual strains. Lactobacillus amylovorus CRL887 was selected for further studies because of its ability to produce significantly higher concentrations of vitamin (81.2 ± 5.4 ?g/L). The safety of this newly identified folate producing strain was evaluated through healthy experimental mice. No bacterial translocation was detected in liver and spleen after consumption of CRL887 during 7 days and no undesirable side effects were observed in the animals that received this strain. This strain in co-culture with previously selected folate producing starter cultures (Lactobacillus bulgaricus CRL871, and Streptococcus thermophilus CRL803 and CRL415) yielded a yogurt containing high folate concentrations (263.1 ± 2.4 ?g/L); a single portion of which would provide 15% of the recommended dietary allowance. This is the first report where a Lactobacillus amylovorus strain was successfully used as co-culture for natural folate bio-enrichment of fermented milk. PMID:25217720

  17. Comparative Genomics of “Dehalococcoides ethenogenes” 195 and an Enrichment Culture Containing Unsequenced “Dehalococcoides” Strains ? †

    OpenAIRE

    West, Kimberlee A.; Johnson, David R.; Hu, Ping; DeSantis, Todd Z.; Brodie, Eoin L; Lee, Patrick K H; Feil, Helene; Andersen, Gary L.; Zinder, Stephen H.; Alvarez-Cohen, Lisa

    2008-01-01

    Tetrachloroethene (PCE) and trichloroethene (TCE) are prevalent groundwater contaminants that can be completely reductively dehalogenated by some “Dehalococcoides” organisms. A Dehalococcoides-organism-containing microbial consortium (referred to as ANAS) with the ability to degrade TCE to ethene, an innocuous end product, was previously enriched from contaminated soil. A whole-genome photolithographic microarray was developed based on the genome of “Dehalococcoides ethenogenes” 195. This mic...

  18. Rapid and Specific Detection of Salmonella spp. in Animal Feed Samples by PCR after Culture Enrichment

    OpenAIRE

    Löfström, Charlotta; Knutsson, Rickard; Axelsson, CE; Rådström, Peter

    2004-01-01

    A PCR procedure has been developed for routine analysis of viable Salmonella spp. in feed samples. The objective was to develop a simple PCR-compatible enrichment procedure to enable DNA amplification without any sample pretreatment such as DNA extraction or cell lysis. PCR inhibition by 14 different feed samples and natural background flora was circumvented by the use of the DNA polymerase Tth. This DNA polymerase was found to exhibit a high level of resistance to PCR inhibitors present in t...

  19. Enrichment and identification of ?9-Tetrahydrocannabinolic acid synthase from Pichia pastoris culture supernatants

    Directory of Open Access Journals (Sweden)

    Kerstin Lange

    2015-09-01

    Full Text Available This data article refers to the report ?9-Tetrahydrocannabinolic acid synthase (THCAS production in Pichia pastoris enables chemical synthesis of cannabinoids (Lange et. al. 2015 [2]. THCAS was produced on a 2 L lab scale using recombinant P. pastoris KM71 KE1. Enrichment of THCAS as a technically pure enzyme was realized using dialysis and cationic exchange chromatography. nLC-ESI-MS/MS analysis identified THCAS in different fractions obtained by cationic exchange chromatography.

  20. Growth and nitrate reduction of Beggiatoa filaments studied in enrichment cultures

    DEFF Research Database (Denmark)

    Kamp, Anja

    2007-01-01

    In this thesis, several aspects of the gliding, filamentous, colourless sulphur bacteria Beggiatoa were investigated. The first part of this thesis addressed the growth mode, breakage of filaments for multiplication, and movement directions of filaments of Beggiatoa. Marine Beggiatoa were enriched in oxygen-sulphide gradient tubes, and observed with a camera system. Growth mode, breakage, and movement directions of Beggiatoa filaments were documented via time-lapse video recording. The initial d...

  1. Stable Nitrogen and Oxygen Isotope Analysis of Nitrate using Denitrifying Bacteria

    Science.gov (United States)

    Edenburn, L.; Michalski, G. M.

    2009-12-01

    The total isotopic composition of nitrate is used for identifying the origin and fate of nitrate in atmospheric, terrestrial and aquatic systems. The analysis of ? 18O, ?15N, and ?17O values each give important and unique information about the sources and sinks of nitrate in these systems. Currently, there is no published method that allows for the simultaneous determination of ?18O, ?15N, and ?17O of nitrate. Cascotti designed a novel method for measurement of ?18O and ?15N in nitrate but not ?17O. This denitrifier method is based on the isotope ratio analysis of nitrous oxide generated by reduction of nitrate by cultured denitrifying bacteria. Kaiser then altered Cascotti's denitrifier method by converting N2O into O2 followed by the quantitative measurement ?18O and ?17O, however ?15N was not measured. Here we present preliminary data on ?15N, ?18O, ?17O values of N2 and O2 generated by the disproportionation of bacterial produced N2O. During the process of denitrification, nitrates are converted to nitrogen gas via a series of intermediate gaseous nitrogen oxide products. This is possible due to the presence of heterotrophic bacteria or autotrophic denitrifiers in select bacteria. Thus, we have chosen three distinct bacteria for the investigation of nitrate reduction for this study: Pseudomonas aureofaciens, Bacillus halodenitrificans, and Achromobacter cycloclastes. They each contain the copper-containing nitrite reductase necessary for the catalyzation of nitrate in order to complete the nitrogen cycle by returning N2 to the atmosphere. Bacillus halodenitrificans has the advantage of being an anaerobic halotolerant (salt-tolerant) denitrifier. Many of our samples have a high saline content; also, pre-concentration techniques using anion resin require elution using high ionic strength solutions. Further, high saline growth solutions limit contamination from other bacteria or organisms. Our efforts also focus on the conversion of N2O over a gold tube into both O2 and N2 using techniques adapted from Cascotti and Kaiser. Our instrument utilizes an extended 11-cup multi-collector feature which does not require a peak jump during analysis on the continuous flow IRMS. Although this is not the first method to study independent measurements of ?18O, ?17O, ?15N, or ?17O, this is first technique that simultaneously detects the stable isotope composition of oxygen and nitrogen in a given nitrate sample. Tests of the impact on isotopic composition by pre-concentration methods have been performed including freeze-drying/evaporation, column chromatography and ion chromatography.

  2. Drinking Water Denitrification using Autotrophic Denitrifying Bacteria in a Fluidized Bed Bioreactor 

    Directory of Open Access Journals (Sweden)

    Abdolmotaleb Seid-mohammadi

    2013-02-01

    Full Text Available Background and Objectives: Contamination of drinking water sources with nitrate may cause adverse effects on human health. Due to operational and maintenance problems of physicochemical nitrate removal processes, using biological denitrification processes have been performed. The aim of this study is to evaluate nitrate removal efficiency from drinking water using autotrophic denitrifying bacteria immobilized on sulfur impregnated activated carbon in a fluidized bed bioreactor. Materials and Methods: After impregnating activated carbon by sulfur as a microorganism carriers and enrichment and inoculation of denitrifying bacteria, a laboratory-scale fluidized bed bioreactor was operated. Nitrate removal efficiency, nitrite, turbidity, hardness and TOC in the effluent were examined during the whole experiment under various conditions including constant influent nitrate concentration as 90 mg NO3--N/l corresponding to different HRT ranging from 5.53 to 1.5 hr. Results: We found that  the denitrification rates was depended on the hydraulic retention time and the nitrate removal efficiency was up to 98%  and nitrite concentration was lower than 1mg/l at optimum HRT=2.4 hr respectively. Moreover, there was no difference in hardness between influent and effluent due to supplying sodium bicarbonate as carbon source for denitrifying bacteria.  However pH, TOC, hardness, and turbidity of the effluent met the W.H.O guidelines for drinking water.  Conclusion: This study demonstrated that an innovative carrier as sulfur impregnated activated carbon could be used as both the biofilm carrier and energy source for treating nitrate contaminated drinking water in the lab-scale fluidized bed bioreactor.

  3. Effects of the antimicrobial sulfamethoxazole on groundwater bacterial enrichment

    Science.gov (United States)

    Underwood, J.C.; Harvey, R.W.; Metge, D.W.; Repert, D.A.; Baumgartner, L.K.; Smith, R.L.; Roane, T.M.; Barber, L.B.

    2011-01-01

    The effects of "trace" (environmentally relevant) concentrations of the antimicrobial agent sulfamethoxazole (SMX) on the growth, nitrate reduction activity, and bacterial composition of an enrichment culture prepared with groundwater from a pristine zone of a sandy drinking-water aquifer on Cape Cod, MA, were assessed by laboratory incubations. When the enrichments were grown under heterotrophic denitrifying conditions and exposed to SMX, noticeable differences from the control (no SMX) were observed. Exposure to SMX in concentrations as low as 0.005 ??M delayed the initiation of cell growth by up to 1 day and decreased nitrate reduction potential (total amount of nitrate reduced after 19 days) by 47% (p = 0.02). Exposure to 1 ??M SMX, a concentration below those prescribed for clinical applications but higher than concentrations typically detected in aqueous environments, resulted in additional inhibitions: reduced growth rates (p = 5 ?? 10-6), lower nitrate reduction rate potentials (p = 0.01), and decreased overall representation of 16S rRNA gene sequences belonging to the genus Pseudomonas. The reduced abundance of Pseudomonas sequences in the libraries was replaced by sequences representing the genus Variovorax. Results of these growth and nitrate reduction experiments collectively suggest that subtherapeutic concentrations of SMX altered the composition of the enriched nitrate-reducing microcosms and inhibited nitrate reduction capabilities. ?? 2011 American Chemical Society.

  4. Cultivation of Mesophilic Soil Crenarchaeotes in Enrichment Cultures from Plant Roots

    OpenAIRE

    Holly M Simon; Jahn, Courtney E.; Bergerud, Luke T.; Marek K. Sliwinski; Weimer, Paul J; Willis, David K.; Goodman, Robert M

    2005-01-01

    Because archaea are generally associated with extreme environments, detection of nonthermophilic members belonging to the archaeal division Crenarchaeota over the last decade was unexpected; they are surprisingly ubiquitous and abundant in nonextreme marine and terrestrial habitats. Metabolic characterization of these nonthermophilic crenarchaeotes has been impeded by their intractability toward isolation and growth in culture. From studies employing a combination of cultivation and molecular...

  5. Temporal Expression of Respiratory Genes in an Enrichment Culture Containing Dehalococcoides ethenogenes

    OpenAIRE

    Rahm, Brian G.; Morris, Robert M.; Richardson, Ruth E

    2006-01-01

    Multiple reductive dehalogenase (RDase), hydrogenase (H2ase), and other respiration-associated (RA) oxidoreductase genes have been identified in cultured representatives of Dehalococcoides. Although their products are likely to play key roles in the environmentally important process of reductive dechlorination, very little information is available about their regulation and specific functions. Here we show increased expression and temporal variability in the expression of five RDase genes and...

  6. Enrichment of mixed cultures capable of aerobic degradation of 1,2-dibromoethane.

    OpenAIRE

    Freitas dos Santos, L M; Leak, D.J.; Livingston, A.G.

    1996-01-01

    1,2-dibromoethane (DBE) is a common environmental contaminant; it is potentially carcinogenic and has been detected in soil and groundwater supplies. Most of the biodegradation studies to date have been performed under anaerobic conditions or in the context of soil remediation, where the pollutant concentration was in the parts per billion range. In this work a mixed bacterial culture capable of complete aerobic mineralization of concentrations of DBE up to 1 g liter(-1) under well-controlled...

  7. Distribution of Microorganisms in Deep-Sea Hydrothermal Vent Chimneys Investigated by Whole-Cell Hybridization and Enrichment Culture of Thermophilic Subpopulations

    OpenAIRE

    Harmsen, H.; Prieur, D; Jeanthon, C.

    1997-01-01

    The microbial community structure of hydrothermal vent chimneys was evaluated by the combined use of enrichment cultures and whole-cell hybridizations with fluorescently labeled 16S rRNA-based oligonucleotide probes. Chimneys were collected during the Microsmoke cruise on the Mid-Atlantic Ridge and were subsampled on board and stored under reduced conditions or fixed. For estimation of culturable thermophiles, selective media were inoculated by dilution series of the samples and incubated at ...

  8. Denitrifying capability and community dynamics of glycogen accumulating organisms during sludge granulation in an anaerobic-aerobic sequencing batch reactor

    Science.gov (United States)

    Bin, Zhang; Bin, Xue; Zhigang, Qiu; Zhiqiang, Chen; Junwen, Li; Taishi, Gong; Wenci, Zou; Jingfeng, Wang

    2015-08-01

    Denitrifying capability of glycogen accumulating organisms (GAOs) has received great attention in environmental science and microbial ecology. Combining this ability with granule processes would be an interesting attempt. Here, a laboratory-scale sequencing batch reactor (SBR) was operated to enrich GAOs and enable sludge granulation. The results showed that the GAO granules were cultivated successfully and the granules had denitrifying capability. The batch experiments demonstrated that all NO3--N could be removed or reduced, some amount of NO2--N were accumulated in the reactor, and N2 was the main gaseous product. SEM analysis suggested that the granules were tightly packed with a large amount of tetrad-forming organisms (TFOs); filamentous bacteria served as the supporting structures for the granules. The microbial community structure of GAO granules was differed substantially from the inoculant conventional activated sludge. Most of the bacteria in the seed sludge grouped with members of Proteobacterium. FISH analysis confirmed that GAOs were the predominant members in the granules and were distributed evenly throughout the granular space. In contrast, PAOs were severely inhibited. Overall, cultivation of the GAO granules and utilizing their denitrifying capability can provide us with a new approach of nitrogen removal and saving more energy.

  9. Pilot-scale chitin extraction from shrimp shell waste by deproteination and decalcification with bacterial enrichment cultures.

    Science.gov (United States)

    Bajaj, Mini; Freiberg, Andrea; Winter, Josef; Xu, Youmei; Gallert, Claudia

    2015-11-01

    Extraction of chitin from mechanically pre-purified shrimp shells can be achieved by successive NaOH/HCl treatment, protease/HCl treatment or by environmentally friendly fermentation with proteolytic/lactic acid bacteria (LAB). For the last mentioned alternative, scale-up of shrimp shell chitin purification was investigated in 0.25 L (F1), 10 L (F2), and 300 L (F3) fermenters using an anaerobic, chitinase-deficient, proteolytic enrichment culture from ground meat for deproteination and a mixed culture of LAB from bio-yoghurt for decalcification. Protein removal in F1, F2, and F3 proceeded in parallel within 40 h at an efficiency of 89-91 %. Between 85 and 90 % of the calcit was removed from the shells by LAB in another 40 h in F1, F2, and F3. After deproteination of shrimp shells in F3, spent fermentation liquor was re-used for a next batch of 30-kg shrimp shells in F4 (300 L) which eliminated 85.5 % protein. The purity of the resulting chitin was comparable in F1, F2, F3, and F4. Viscosities of chitosan, obtained after chitin deacetylation and of chitin, prepared biologically or chemically in the laboratory, were much higher than those of commercially available chitin and chitosan. PMID:26227412

  10. Characterization of bacterial diversity in an atrazine degrading enrichment culture and degradation of atrazine, cyanuric acid and biuret in industrial wastewater.

    Science.gov (United States)

    Dutta, Anirban; Vasudevan, Venugopal; Nain, Lata; Singh, Neera

    2016-01-01

    An enrichment culture was used to study atrazine degradation in mineral salt medium (MSM) (T1), MSM+soil extract (1:1, v/v) (T2) and soil extract (T3). Results suggested that enrichment culture required soil extract to degrade atrazine, as after second sequential transfer only partial atrazine degradation was observed in T1 treatment while atrazine was completely degraded in T2 and T3 treatments even after fourth transfer. Culture independent polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique confirmed selective enrichment of genus Bacillus along with Pseudomonas and Burkholderia. Degradation of atrazine/metabolites in the industrial wastewater was studied at different initial concentrations of the contaminants [wastewater-water (v/v) ratio: T1, 1:9; T2, 2:8; T3, 3:7; T4, 5:5 and T5, undiluted effluent]. The initial concentrations of atrazine, cyanuric acid and biuret ranged between 5.32 and 53.92 µg mL(-1), 265.6 and 1805.2 µg mL(-1) and 1.85 and 16.12 µg mL(-1), respectively. The enrichment culture was able to completely degrade atrazine, cyanuric acid and biuret up to T4 treatment, while no appreciable degradation of contaminants was observed in the undiluted effluent (T5). Inability of enrichment culture to degrade atrazine/metabolites might be due to high concentrations of cyanuric acid. Therefore, a separate study on cyanuric acid degradation suggested: (i) no appreciable cyanuric acid degradation with accumulation of an unidentified metabolite in the medium where cyanuric acid was supplemented as the sole source of carbon and nitrogen; (ii) partial cyanuric acid degradation with accumulation of unidentified metabolite in the medium containing additional nitrogen source; and (iii) complete cyanuric acid degradation in the medium supplemented with an additional carbon source. This unidentified metabolite observed during cyanuric acid degradation and also detected in the enrichment culture inoculated wastewater samples, however, was degraded up to T4 treatments and was persistent in the T5 treatment. Probably, accumulation of this metabolite inhibited atrazine/cyanuric acid degradation by the enrichment culture in undiluted wastewater. PMID:26479154

  11. Inhibitory Effect of Gamma-Irradiated Chitosan on the Growth of Denitrifiers

    Directory of Open Access Journals (Sweden)

    Javier Vilcáez

    2009-01-01

    Full Text Available In order to find an environmentally benign substitute to hazardous inhibitory agents, the inhibitory effect of ?-irradiated chitosans against a mixed culture of denitrifying bacteria was experimentally evaluated. Unlike other studies using pure aerobic cultures, the observed effect was not a complete inhibition but a transient inhibition reflected by prolonged lag phases and reduced growth rates. Raw chitosan under acid conditions (pH 6.3 exerted the strongest inhibition followed by the 100?kGy and 500?kGy irradiated chitosans, respectively. Therefore, because the molecular weight of chitosan decreases with the degree of ?-irradiation, the inhibitory properties of chitosan due to its high molecular weight were more relevant than the inhibitory properties gained due to the modification of the surface charge and/or chemical structure by ?-irradiation. High dosage of ?-irradiated appeared to increase the growth of mixed denitrifying bacteria in acid pH media. However, in neutral pH media, high dosage of ?-irradiation appeared to enhance the inhibitory effect of chitosan.

  12. Cultivation and irradiation of human fibroblasts in a medium enriched with platelet lysate for obtaining feeder layer in epidermal cell culture

    International Nuclear Information System (INIS)

    For over 30 years, the use of culture medium, enriched with bovine serum, and murines fibroblasts, with the rate of proliferation controlled by irradiation or by share anticarcinogenic drugs, has been playing successfully its role in assisting in the development of keratinocytes in culture, for clinical purposes. However, currently there is a growing concern about the possibility of transmitting prions and animals viruses to transplanted patients. Taking into account this concern, the present work aims to cultivate human fibroblasts in a medium enriched with human platelets lysate and determine the irradiation dose of these cells, for obtaining feeder layer in epidermal cell culture. For carrying out the proposed objective, platelets lysis has standardized, this lysate was used for human fibroblasts cultivation and the irradiation dose enough to inhibit its duplication was evaluated. Human keratinocytes were cultivated in these feeder layers, in culture medium enriched with the lysate. With these results we conclude that the 10% platelets lysate promoted a better adhesion and proliferation of human fibroblasts and in all dose levels tested (60 to 300 Gy), these had their mitotic activity inactivated by ionizing irradiation, being that the feeder layers obtained with doses from 70 to 150 Gy were those that provided the best development of keratinocytes in medium containing 2.5% of human platelet lysate. Therefore, it was possible to standardize both the cultivation of human fibroblasts as its inactivation for use as feeder layer in culture of keratinocytes, so as to eliminate xenobiotics components. (author)

  13. Proteins differentially expressed in human beta-cells-enriched pancreatic islet cultures and human insulinomas

    DEFF Research Database (Denmark)

    Terra, Letícia F; Teixeira, Priscila C

    2013-01-01

    In view of the great demand for human beta-cells for physiological and medical studies, we generated cell lines derived from human insulinomas which secrete insulin, C-peptide and express neuroendocrine and islet markers. In this study, we set out to characterize their proteomes, comparing them to those of primary beta-cells using DIGE followed by MS. The results were validated by Western blotting. An average of 1800 spots was detected with less than 1% exhibiting differential abundance. Proteins more abundant in human islets, such as Caldesmon, are involved in the regulation of cell contractility, adhesion dependent signaling, and cytoskeletal organization. In contrast, almost all proteins more abundant in insulinoma cells, such as MAGE2, were first described here and could be related to cell survival and resistance to chemotherapy. Our proteomic data provides, for the first time, a molecular snapshot of the orchestrated changes in expression of proteins involved in key processes which could be correlated with the altered phenotype of human beta-cells. Collectively our observations prompt research towards the establishment of bioengineered human beta-cells providing a new and needed source of cultured human beta-cells for beta-cell research, along with the development of new therapeutic strategies for detection, characterization and treatment of insulinomas.

  14. Diversity and activity of denitrifiers of Chilean arid soil ecosystems

    Directory of Open Access Journals (Sweden)

    GescheBraker

    2012-04-01

    Full Text Available The Chilean sclerophyllous matorral is a Mediterranean semiarid ecosystem affected by erosion, with low soil fertility and limited by nitrogen. However, limitation of resources is even more severe for desert soils such as from the Atacama Desert, one of the most extreme arid deserts on Earth. Topsoil organic matter, nitrogen and moisture content were significantly higher in the semiarid soil compared to the desert soil. Although the most significant loss of biologically preferred nitrogen from terrestrial ecosystems occurs via denitrification, virtually nothing is known on the activity and composition of denitrifier communities thriving in arid soils. In this study, we explored denitrifier communities from two soils with profoundly distinct edaphic factors. While denitrification activity in the desert soil was below detection limit, the semiarid soil sustained denitrification activity. To elucidate the genetic potential of the soils to sustain denitrification processes we performed community analysis of denitrifiers based on nitrite reductase (nirK and nirS genes as functional marker genes for this physiological group. Presence of nirK-type denitrifiers in both soils was demonstrated but failure to amplify nirS from the desert soil suggests very low abundance of nirS-type denitrifiers shedding light on the lack of denitrification activity. Phylogenetic analysis showed a very low diversity of nirK with only three distinct genotypes in the desert soil which conditions presumably exert a high selection pressure. While nirK diversity was also limited to only few, albeit distinct genotypes, the semiarid matorral soil showed a surprisingly broad genetic variability of the nirS gene. The Chilean matorral is a shrub land plant community which form vegetational patches stabilizing the soil and increasing its nitrogen and carbon content. These islands of fertility may sustain the development and activity of the overall microbial community and of denitrifiers in particular.

  15. Rapid and Specific Enrichment of Culturable Gram Negative Bacteria Using Non-Lethal Copper-Free Click Chemistry Coupled with Magnetic Beads Separation

    Science.gov (United States)

    Fugier, Emilie; Dumont, Audrey; Malleron, Annie; Poquet, Enora; Mas Pons, Jordi; Baron, Aurélie; Vauzeilles, Boris; Dukan, Sam

    2015-01-01

    Currently, identification of pathogenic bacteria present at very low concentration requires a preliminary culture-based enrichment step. Many research efforts focus on the possibility to shorten this pre-enrichment step which is needed to reach the minimal number of cells that allows efficient identification. Rapid microbiological controls are a real public health issue and are required in food processing, water quality assessment or clinical pathology. Thus, the development of new methods for faster detection and isolation of pathogenic culturable bacteria is necessary. Here we describe a specific enrichment technique for culturable Gram negative bacteria, based on non-lethal click chemistry and the use of magnetic beads that allows fast detection and isolation. The assimilation and incorporation of an analog of Kdo, an essential component of lipopolysaccharides, possessing a bio-orthogonal azido function (Kdo-N3), allow functionalization of almost all Gram negative bacteria at the membrane level. Detection can be realized through strain-promoted azide-cyclooctyne cycloaddition, an example of click chemistry, which interestingly does not affect bacterial growth. Using E. coli as an example of Gram negative bacterium, we demonstrate the excellent specificity of the technique to detect culturable E. coli among bacterial mixtures also containing either dead E. coli, or live B. subtilis (as a model of microorganism not containing Kdo). Finally, in order to specifically isolate and concentrate culturable E. coli cells, we performed separation using magnetic beads in combination with click chemistry. This work highlights the efficiency of our technique to rapidly enrich and concentrate culturable Gram negative bacteria among other microorganisms that do not possess Kdo within their cell envelope. PMID:26061695

  16. Rate of denitrification and the accumulation of intermediates in a denitrifying bioreactor

    Science.gov (United States)

    Parsignault, D. R.; Gursky, H.; Kellogg, E. M.; Matilsky, T.; Murray, S.; Schreier, E.; Tananbaum, H.; Giacconi, R.; Brinkman, A. C.

    2012-12-01

    Denitrifying bioreactors (DNBRs) are an emerging mechanism to mitigate the impact of excess reactive nitrogen by harnessing the activity of ubiquitous denitrifying soil microbes. DNBRs fundamentally consist of an organic carbon energy source sufficiently saturated to develop anaerobic conditions and support heterotrophic reduction of nitrate to dinitrogen. Although recent research has well established achievable nitrate removal in DNBRs upwards of 90%, few studies experimentally determine the fate of nitrogen in these systems. This study differentiates between denitrification to inert nitrogen gas, which permanently removes reactive nitrogen from an enriched ecosystem, and transformation of nitrate to another bioavailable form (such as N2O or NOX, powerful greenhouse gases). Previous research has failed to make this distinction and as both are perceived as a reduction in nitrate concentration at the outlet, the utility of DNBRs in reducing downstream reactive nitrogen has not been sufficiently established. In order to quantify the rate of nitrate removal and the products produced, dissolved gas samples are collected from the DNBR with passive diffusion gas samplers while the influent and effluent nitrate concentration and chemical oxygen demand are monitored in real time with spectrometer probes. Nitrate removal is compared with the denitrification rate and the ratio of dinitrogen to nitrous oxide is reported. Denitrification is quantified from the proportion of nitrogen gas products produced from the nitrate pool, indicated by the negative congruence of the regression of 15N enrichment in the nitrate pool and temporal depletion in the gaseous products. The proportion of nitrous oxide to dinitrogen is examined with respect to saturation and redox potential. This research informs the interpretation of previous studies as well as advises the focus of long-term system level monitoring that will provide further information on the design and application of DNBRs to mitigate nitrate pollution.

  17. Isotope effects and O-exchange with water during N2O production by denitrifying fungi

    Science.gov (United States)

    Rohe, Lena; Braker, Gesche; Well, Reinhard; Giesemann, Anette; Anderson, Traute-Heidi; Wrage-Mönnig, Nicole; Flessa, Heinz

    2013-04-01

    N2O from soil denitrification originates from bacteria and - to an unknown extent - also from fungi. In pure culture studies, bacterial and fungal denitrification showed differences in isotopomer ratios of N2O. Isotopomer ratios of N2O can be expressed as 15N site preference (SP), i.e. the difference between ?15N of the central and terminal N-position of the asymmetric N2O molecule and might be suitable to distinguish between bacterial and fungal N2O under denitrifying soil conditions. Oxygen exchange takes place between H2O and intermediates during the denitrification process. Several studies showed that O-exchange of bacterial denitrifiers varies, but information about fungal O-exchanges is lacking. The objectives of the study presented are i) to verify SP of fungal N2O reported for two strains from pure culture studies and ii) to analyze the oxygen exchange between intermediates and H2O during denitrification in fungal pure cultures. Six different fungal pure cultures known to be capable of denitrification were incubated under anaerobic conditions, either with nitrite or nitrate. Gas samples were analysed for concentration and isotopic signatures (SP, average ?15N, ?18O) of N2O. To investigate the oxygen exchange, both treatments were also established in a tracer experiment where 18O-labelled water was used in the medium. The fungal strains evaluated so far indicate similar SP as reported previously. Concerning the amount of N2O produced, the nitrite led to a higher yield than nitrate. O-exchange with 18O-labelled water during fungal denitrification was visible. Using nitrite, the exchange ranged amounted from 39% to full exchange while nitrate led to exchange rates between 13% and full exchange. Detailed results will be presented.

  18. Higher diversity and abundance of denitrifying microorganisms in environments than considered previously.

    Science.gov (United States)

    Wei, Wei; Isobe, Kazuo; Nishizawa, Tomoyasu; Zhu, Lin; Shiratori, Yutaka; Ohte, Nobuhito; Koba, Keisuke; Otsuka, Shigeto; Senoo, Keishi

    2015-09-01

    Denitrification is an important process in the global nitrogen cycle. The genes encoding NirK and NirS (nirK and nirS), which catalyze the reduction of nitrite to nitric oxide, have been used as marker genes to study the ecological behavior of denitrifiers in environments. However, conventional polymerase chain reaction (PCR) primers can only detect a limited range of the phylogenetically diverse nirK and nirS. Thus, we developed new PCR primers covering the diverse nirK and nirS. Clone library and qPCR analysis using the primers showed that nirK and nirS in terrestrial environments are more phylogenetically diverse and 2-6 times more abundant than those revealed with the conventional primers. RNA- and culture-based analyses using a cropland soil also suggested that microorganisms with previously unconsidered nirK or nirS are responsible for denitrification in the soil. PCR techniques still have a greater capacity for the deep analysis of target genes than PCR-independent methods including metagenome analysis, although efforts are needed to minimize the PCR biases. The methodology and the insights obtained here should allow us to achieve a more precise understanding of the ecological behavior of denitrifiers and facilitate more precise estimate of denitrification in environments. PMID:25756678

  19. Effect of Earthworm Feeding Guilds on Ingested Dissimilatory Nitrate Reducers and Denitrifiers in the Alimentary Canal of the Earthworm ? †

    Science.gov (United States)

    Depkat-Jakob, Peter S.; Hilgarth, Maik; Horn, Marcus A.; Drake, Harold L.

    2010-01-01

    The earthworm gut is an anoxic nitrous oxide (N2O)-emitting microzone in aerated soils. In situ conditions of the gut might stimulate ingested nitrate-reducing soil bacteria linked to this emission. The objective of this study was to determine if dissimilatory nitrate reducers and denitrifiers in the alimentary canal were affected by feeding guilds (epigeic [Lumbricus rubellus], anecic [Lumbricus terrestris], and endogeic [Aporrectodea caliginosa]). Genes and gene transcripts of narG (encodes a subunit of nitrate reductase and targets both dissimilatory nitrate reducers and denitrifiers) and nosZ (encodes a subunit of N2O reductase and targets denitrifiers) were detected in guts and soils. Gut-derived sequences were similar to those of cultured and uncultured soil bacteria and to soil-derived sequences obtained in this study. Gut-derived narG sequences and narG terminal restriction fragments (TRFs) were affiliated mainly with Gram-positive organisms (Actinobacteria). The majority of gut- and uppermost-soil-derived narG transcripts were affiliated with Mycobacterium (Actinobacteria). In contrast, narG sequences indicative of Gram-negative organisms (Proteobacteria) were dominant in mineral soil. Most nosZ sequences and nosZ TRFs were affiliated with Bradyrhizobium (Alphaproteobacteria) and uncultured soil bacteria. TRF profiles indicated that nosZ transcripts were more affected by earthworm feeding guilds than were nosZ genes, whereas narG transcripts were less affected by earthworm feeding guilds than were narG genes. narG and nosZ transcripts were different and less diverse in the earthworm gut than in mineral soil. The collective results indicate that dissimilatory nitrate reducers and denitrifiers in the earthworm gut are soil derived and that ingested narG- and nosZ-containing taxa were not uniformly stimulated in the guts of worms from different feeding guilds. PMID:20656855

  20. Effect of earthworm feeding guilds on ingested dissimilatory nitrate reducers and denitrifiers in the alimentary canal of the earthworm.

    Science.gov (United States)

    Depkat-Jakob, Peter S; Hilgarth, Maik; Horn, Marcus A; Drake, Harold L

    2010-09-01

    The earthworm gut is an anoxic nitrous oxide (N(2)O)-emitting microzone in aerated soils. In situ conditions of the gut might stimulate ingested nitrate-reducing soil bacteria linked to this emission. The objective of this study was to determine if dissimilatory nitrate reducers and denitrifiers in the alimentary canal were affected by feeding guilds (epigeic [Lumbricus rubellus], anecic [Lumbricus terrestris], and endogeic [Aporrectodea caliginosa]). Genes and gene transcripts of narG (encodes a subunit of nitrate reductase and targets both dissimilatory nitrate reducers and denitrifiers) and nosZ (encodes a subunit of N(2)O reductase and targets denitrifiers) were detected in guts and soils. Gut-derived sequences were similar to those of cultured and uncultured soil bacteria and to soil-derived sequences obtained in this study. Gut-derived narG sequences and narG terminal restriction fragments (TRFs) were affiliated mainly with Gram-positive organisms (Actinobacteria). The majority of gut- and uppermost-soil-derived narG transcripts were affiliated with Mycobacterium (Actinobacteria). In contrast, narG sequences indicative of Gram-negative organisms (Proteobacteria) were dominant in mineral soil. Most nosZ sequences and nosZ TRFs were affiliated with Bradyrhizobium (Alphaproteobacteria) and uncultured soil bacteria. TRF profiles indicated that nosZ transcripts were more affected by earthworm feeding guilds than were nosZ genes, whereas narG transcripts were less affected by earthworm feeding guilds than were narG genes. narG and nosZ transcripts were different and less diverse in the earthworm gut than in mineral soil. The collective results indicate that dissimilatory nitrate reducers and denitrifiers in the earthworm gut are soil derived and that ingested narG- and nosZ-containing taxa were not uniformly stimulated in the guts of worms from different feeding guilds. PMID:20656855

  1. Hydraulic flow characteristics of agricultural residues for denitrifying bioreactor media

    Science.gov (United States)

    Denitrifying bioreactors are a promising technology to mitigate agricultural subsurface drainage nitrate-nitrogen losses, a critical water quality goal for the Upper Mississippi River Basin. This study was conducted to evaluate the hydraulic properties of agricultural residues that are potential bio...

  2. Trace Gas Emission from in-Situ Denitrifying Bioreactors

    Science.gov (United States)

    Pluer, W.; Walter, M. T.; Geohring, L.

    2014-12-01

    Despite decades of concerted effort to mitigate nonpoint source nitrate (NO3-) pollution from agricultural lands, these efforts have not been sufficient to arrest eutrophication. A primary process for removing excess NO3- from water is denitrification, where denitrifying bacteria use NO3- for respiration in the absence of oxygen. Denitrification results in reduced forms of nitrogen, often dinitrogen gas (N2) but also nitrous oxide (N2O), an aggressive greenhouse gas. A promising solution to NO3- pollution is to intercept agricultural discharges with denitrifying bioreactors (DNBRs). DNBRs provide conditions ideal for denitrifiers: an anaerobic environment, sufficient organic matter, and excess NO3-. These conditions are also ideal for methanogens, which produce methane (CH4), another harmful trace gas. While initial results from bioreactor studies show that they can cost-effectively remove NO3-, trace gas emissions are an unintended consequence. This study's goal was to determine how bioreactor design promotes denitrification while limiting trace gas production. Reactor inflow and outflow water samples were tested for nutrients, including NO3-, and dissolved inflow and outflow gas samples were tested for N2O and CH4. NO3- reduction and trace gas production were evaluated at various residence times, pHs, and inflow NO3- concentrations in field and lab-scale reactors. Low NO3- reduction indicated conditions that stressed denitrifying bacteria while high reductions indicated designs that optimized pollutant treatment for water quality. Several factors influenced high N2O, suggesting non-ideal conditions for the final step of complete denitrification. High CH4 emissions pointed to reactor media choice for discouraging methanogens, which may remove competition with denitrifiers. It is critical to understand all of potential impacts that DNBRs may have, which means identifying processes and design specifications that may affect them.

  3. Complete Detoxification of Vinyl Chloride by an Anaerobic Enrichment Culture and Identification of the Reductively Dechlorinating Population as a Dehalococcoides Species

    OpenAIRE

    He, Jianzhong; Ritalahti, Kirsti M; Aiello, Michael R.; Löffler, Frank E

    2003-01-01

    A major obstacle in the implementation of the reductive dechlorination process at chloroethene-contaminated sites is the accumulation of the intermediate vinyl chloride (VC), a proven human carcinogen. To shed light on the microbiology involved in the final critical dechlorination step, a sediment-free, nonmethanogenic, VC-dechlorinating enrichment culture was derived from tetrachloroethene (PCE)-to-ethene-dechlorinating microcosms established with material from the chloroethene-contaminated ...

  4. Combined Genomic and Proteomic Approaches Identify Gene Clusters Involved in Anaerobic 2-Methylnaphthalene Degradation in the Sulfate-Reducing Enrichment Culture N47?

    OpenAIRE

    Selesi, Draženka; Jehmlich, Nico; von Bergen, Martin; Schmidt, Frank; Rattei, Thomas; Tischler, Patrick; Lueders, Tillmann; Meckenstock, Rainer U.

    2009-01-01

    The highly enriched deltaproteobacterial culture N47 anaerobically oxidizes the polycyclic aromatic hydrocarbons naphthalene and 2-methylnaphthalene, with sulfate as the electron acceptor. Combined genome sequencing and liquid chromatography-tandem mass spectrometry-based shotgun proteome analyses were performed to identify genes and proteins involved in anaerobic aromatic catabolism. Proteome analysis of 2-methylnaphthalene-grown N47 cells resulted in the identification of putative enzymes c...

  5. Preparation of glycerol-enriched yeast culture and its effect on blood metabolites and ruminal fermentation in goats.

    Science.gov (United States)

    Ye, Gengping; Zhu, Yongxing; Liu, Jin; Chen, Xingxiang; Huang, Kehe

    2014-01-01

    The aim of this study was to isolate a glycerol-producing yeast strain from nature to prepare glycerol-enriched yeast culture (GY), and preliminarily evaluate the effects of GY on blood metabolites and ruminal fermentation in goats. During the trial, six isolates were isolated from unprocessed honey, and only two isolates with higher glycerol yield were identified by analysis of 26S ribosomal DNA sequences. One of the two isolates was identified as Saccharomyces cerevisiae, a direct-fed microbe permitted by the FDA. This isolate was used to prepare GY. The fermentation parameters were optimized through single-factor and orthogonal design methods to maximize the glycerol yield and biomass. The final GY contained 38.7±0.6 g/L glycerol and 12.6±0.5 g/L biomass. In vivo, eight castrated male goats with ruminal fistula were used in a replicated 4×4 Latin square experiment with four consecutive periods of 15 d. Treatments were as follows: control, LGY, MGY, and HGY with 0, 100, 200, and 300 mL GY per goat per day, respectively. The GY was added in two equal portions at 08?00 and 17?00 through ruminal fistula. Samples of blood and ruminal fluid were collected on the last one and two days of each period, respectively. Results showed that the plasma concentrations of triglyceride and total cholesterol were not affected by the supplemented GY. Compared with the control, goats supplemented with MGY and HGY had significantly higher (Pglucose and total protein, ruminal volatile fatty acid and molar proportion of propionate, and significantly lower (Peffects of glycerol and yeast for ruminants. PMID:24709881

  6. Comparative metagenomics of three Dehalococcoides-containing enrichment cultures: the role of the non-dechlorinating community

    Directory of Open Access Journals (Sweden)

    Hug Laura A

    2012-07-01

    Full Text Available Abstract Background The Dehalococcoides are strictly anaerobic bacteria that gain metabolic energy via the oxidation of H2 coupled to the reduction of halogenated organic compounds. Dehalococcoides spp. grow best in mixed microbial consortia, relying on non-dechlorinating members to provide essential nutrients and maintain anaerobic conditions. A metagenome sequence was generated for the dechlorinating mixed microbial consortium KB-1. A comparative metagenomic study utilizing two additional metagenome sequences for Dehalococcoides-containing dechlorinating microbial consortia was undertaken to identify common features that are provided by the non-dechlorinating community and are potentially essential to Dehalococcoides growth. Results The KB-1 metagenome contained eighteen novel homologs to reductive dehalogenase genes. The metagenomes obtained from the three consortia were automatically annotated using the MG-RAST server, from which statistically significant differences in community composition and metabolic profiles were determined. Examination of specific metabolic pathways, including corrinoid synthesis, methionine synthesis, oxygen scavenging, and electron-donor metabolism identified the Firmicutes, methanogenic Archaea, and the ?-Proteobacteria as key organisms encoding these pathways, and thus potentially producing metabolites required for Dehalococcoides growth. Conclusions Comparative metagenomics of the three Dehalococcoides-containing consortia identified that similarities across the three consortia are more apparent at the functional level than at the taxonomic level, indicating the non-dechlorinating organisms’ identities can vary provided they fill the same niche within a consortium. Functional redundancy was identified in each metabolic pathway of interest, with key processes encoded by multiple taxonomic groups. This redundancy likely contributes to the robust growth and dechlorination rates in dechlorinating enrichment cultures.

  7. Changes in glucose fermentation pathways by an enriched bacterial culture in response to regulated dissolved H2 concentrations.

    Science.gov (United States)

    Zheng, Hang; Zeng, Raymond J; Duke, Mikel C; O'Sullivan, Cathryn A; Clarke, William P

    2015-06-01

    It is well established that metabolic pathways in the fermentation of organic waste are primarily controlled by dissolved H2 concentrations, but there is no reported study that compares observed and predicted shifts in fermentation pathways induced by manipulating the dissolved H2 concentration. A perfusion system is presented that was developed to control dissolved H2 concentrations in the continuous fermentation of glucose by a culture highly enriched towards Thermoanaerobacterium thermosaccharolyticum (86?±?9% relative abundance) from an originally diverse consortia in the leachate of a laboratory digester fed with municipal solid waste. Media from a 2.5?L CSTR was drawn through sintered steel membrane filters to retain biomass, allowing vigorous sparging in a separate chamber without cellular disruption. Through a combination of sparging and variations in glucose feeding rate from 0.8 to 0.2?g/L/d, a range of steady state fermentations were performed with dissolved H2 concentrations as low as an equivalent equilibrated H2 partial pressure of 3?kPa. Trends in product formation rates were simulated using a H2 regulation partitioning model. The model correctly predicted the direction of products redistribution in response to H2 concentration changes and the acetate and butyrate formation rates when H2 concentrations were less than 6?kPa. However, the model over-estimated acetate, ethanol and butanol productions at the expense of butyrate production at higher H2 concentrations. The H2 yield at the lowest dissolved H2 concentration was 2.67?±?0.08?mol H2 /mol glucose, over 300% higher than the yield achieved in a CSTR operated without sparging. PMID:25545692

  8. Distribution of Microorganisms in Deep-Sea Hydrothermal Vent Chimneys Investigated by Whole-Cell Hybridization and Enrichment Culture of Thermophilic Subpopulations

    Science.gov (United States)

    Harmsen, H.; Prieur, D.; Jeanthon, C.

    1997-01-01

    The microbial community structure of hydrothermal vent chimneys was evaluated by the combined use of enrichment cultures and whole-cell hybridizations with fluorescently labeled 16S rRNA-based oligonucleotide probes. Chimneys were collected during the Microsmoke cruise on the Mid-Atlantic Ridge and were subsampled on board and stored under reduced conditions or fixed. For estimation of culturable thermophiles, selective media were inoculated by dilution series of the samples and incubated at 65, 80, and 95(deg)C. To analyze the microbial diversity of the samples, cells were extracted from the fixed chimney structure samples and hybridized with domain- and kingdom-specific probes. Quantification of the extracted cells was assessed by whole-cell hybridization on membrane filters. By both methods, the largest amounts of microorganisms were found in the upper and outer parts of the chimneys, although even the inner parts contained culturable and detectable amounts of cells. Different morphotypes of thermophilic and hyperthermophilic microorganisms were enriched and detected in samples. Our data clearly indicate that the morphological diversity observed by using whole-cell hybridization is much larger than that assessed by use of culture-based enrichments. This new approach, including culture-independent and -dependent methods to study hydrothermal vent chimneys, showed an uneven distribution of a diverse microbial community. Application of lower-level specific probes for known families and genera within each domain by our approach will be useful to reveal the real extent and nature of the chimney microbial diversity and to support cultivation attempts. PMID:16535655

  9. Treatment and electricity harvesting from sulfate/sulfide-containing wastewaters using microbial fuel cell with enriched sulfate-reducing mixed culture

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Duu-Jong, E-mail: cedean@mail.ntust.edu.tw [Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan (China); Lee, Chin-Yu [Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan (China); Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan (China); Center for Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan (China); Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer We started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture. Black-Right-Pointing-Pointer Sulfate-reducing bacteria and anode-respiring bacteria were enriched in anodic biofilms. Black-Right-Pointing-Pointer The MFC effectively remove sulfate to elementary sulfur in the presence of lactate. Black-Right-Pointing-Pointer The present device can treat sulfate laden wastewaters with electricity harvesting. - Abstract: Anaerobic treatment of sulfate-laden wastewaters can produce excess sulfide, which is corrosive to pipelines and is toxic to incorporated microorganisms. This work started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture as anodic biofilms and applied the so yielded MFC for treating sulfate or sulfide-laden wastewaters. The sulfate-reducing bacteria in anodic biofilm effectively reduced sulfate to sulfide, which was then used by neighboring anode respiring bacteria (ARB) as electron donor for electricity production. The presence of organic carbons enhanced MFC performance since the biofilm ARB were mixotrophs that need organic carbon to grow. The present device introduces a route for treating sulfate laden wastewaters with electricity harvesting.

  10. Treatment and electricity harvesting from sulfate/sulfide-containing wastewaters using microbial fuel cell with enriched sulfate-reducing mixed culture

    International Nuclear Information System (INIS)

    Highlights: ? We started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture. ? Sulfate-reducing bacteria and anode-respiring bacteria were enriched in anodic biofilms. ? The MFC effectively remove sulfate to elementary sulfur in the presence of lactate. ? The present device can treat sulfate laden wastewaters with electricity harvesting. - Abstract: Anaerobic treatment of sulfate-laden wastewaters can produce excess sulfide, which is corrosive to pipelines and is toxic to incorporated microorganisms. This work started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture as anodic biofilms and applied the so yielded MFC for treating sulfate or sulfide-laden wastewaters. The sulfate-reducing bacteria in anodic biofilm effectively reduced sulfate to sulfide, which was then used by neighboring anode respiring bacteria (ARB) as electron donor for electricity production. The presence of organic carbons enhanced MFC performance since the biofilm ARB were mixotrophs that need organic carbon to grow. The present device introduces a route for treating sulfate laden wastewaters with electricity harvesting.

  11. Isolation and Molecular Identification of an Aerobic Denitrifier

    Directory of Open Access Journals (Sweden)

    Hongyu Wang

    2013-10-01

    Full Text Available Six bacteria strains of which total nitrogen removal efficiency is over 70% were isolated from the activated sludge after enrichment culture. The strain Z31 with higher nitrogen removal was selected and its characteristic of aerobic denitrification was confirmed by the nitrogen element track. The results showed that the nitrate in the culture could be efficiently removed by strain Z31 and the nitrate nitrogen removal rate was up to above 95%. There was obvious nitrite accumulation during the denitrification process. Moreover, medium pH was increased and medium ORP was decreased as a result of denitrification. According to the morphological observation, physiological biochemical test and sequence analysis of the 16S rDNA, strain Z31 was identified as Pseudomonas stutzeri. And the phylogentic position of the strain was performed based on the phylogenetic tree.

  12. Determination of alachlor and its metabolite 2,6-diethylaniline in microbial culture medium using online microdialysis enriched-sampling coupled to high-performance liquid chromatography.

    Science.gov (United States)

    Chen, Chi-Zen; Yan, Cheing-Tong; Kumar, Ponnusamy Vinoth; Huang, Jenn-Wen; Jen, Jen-Fon

    2011-08-10

    In this study, a simple and novel microdialysis sampling technique incorporating hollow fiber liquid phase microextraction (HF-LPME) coupled online to high-performance liquid chromatography (HPLC) for the one-step sample pretreatment and direct determination of alachlor (2-chloro-2',6'-diethyl-N -(methoxymethyl)acetanilide) and its metabolite 2,6-diethylaniline (2,6-DEA) in microbial culture medium has been developed. A reversed-phase C-18 column was utilized to separate alachlor and 2,6-DEA from other species using an acetonitrile/water mixture (1:1) containing 0.1 M phosphate buffer solution at pH 7.0 as the mobile phase. Detection was carried out with a UV detector operated at 210 nm. Parameters that influenced the enrichment efficiency of online HF-LPME sampling, including the length of the hollow fiber, the perfusion solvent and its flow rate, the pH, and the salt added in sample solution, as well as chromatographic conditions were thoroughly optimized. Under optimal conditions, excellent enrichment efficiency was achieved by the microdialysis of a sample solution (pH 7.0) using hexane as perfusate at the flow rate of 4 ?L/min. Detection limits were 72 and 14 ng/mL for alachlor and 2,6-DEA, respectively. The enrichment factors were 403 and 386 (RSD alachlor and 2,6-DEA, respectively, when extraction was performed by using a 40 cm regenerated cellulose hollow fiber and hexane as perfusion solvent at the flow rate of 0.1 ?L/min. The proposed method provides a sensitive, flexible, fast, and eco-friendly procedure to enrich and determine alachlor and its metabolite (2,6-DEA) in microbial culture medium. PMID:21707080

  13. Warming-induced changes in denitrifier community structure modulate the ability of phototrophic river biofilms to denitrify

    Energy Technology Data Exchange (ETDEWEB)

    Boulêtreau, Stéphanie, E-mail: stephanie.bouletreau@univ-tlse3.fr [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Lyautey, Emilie [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Dubois, Sophie [Université de Bordeaux, EPOC - OASU, UMR 5805, Station Marine d' Arcachon, 2 rue du Professeur Jolyet, 33120 Arcachon (France); Compin, Arthur [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Delattre, Cécile; Touron-Bodilis, Aurélie [EDF Recherche et Développement, LNHE (Laboratoire National d' Hydraulique et Environnement), 6 quai Watier, F-78401 Chatou (France); Mastrorillo, Sylvain [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Garabetian, Frédéric [Université de Bordeaux, EPOC - OASU, UMR 5805, Station Marine d' Arcachon, 2 rue du Professeur Jolyet, 33120 Arcachon (France)

    2014-01-01

    Microbial denitrification is the main nitrogen removing process in freshwater ecosystems. The aim of this study was to show whether and how water warming (+ 2.5 °C) drives bacterial diversity and structuring and how bacterial diversity affects denitrification enzymatic activity in phototrophic river biofilms (PRB). We used water warming associated to the immediate thermal release of a nuclear power plant cooling circuit to produce natural PRB assemblages on glass slides while testing 2 temperatures (mean temperature of 17 °C versus 19.5 °C). PRB were sampled at 2 sampling times during PRB accretion (6 and 21 days) in both temperatures. Bacterial community composition was assessed using ARISA. Denitrifier community abundance and denitrification gene mRNA levels were estimated by q-PCR and qRT-PCR, respectively, of 5 genes encoding catalytic subunits of the denitrification key enzymes. Denitrification enzyme activity (DEA) was measured by the acetylene-block assay at 20 °C. A mean water warming of 2.5 °C was sufficient to produce contrasted total bacterial and denitrifier communities and, therefore, to affect DEA. Indirect temperature effect on DEA may have varied between sampling time, increasing by up to 10 the denitrification rate of 6-day-old PRB and decreasing by up to 5 the denitrification rate of 21-day-old PRB. The present results suggest that indirect effects of warming through changes in bacterial community composition, coupled to the strong direct effect of temperature on DEA already demonstrated in PRB, could modulate dissolved nitrogen removal by denitrification in rivers and streams. - Highlights: •We produced river biofilms in 2 mean temperature conditions: 17 vs 19.5 °C. •We compared their denitrifiers' structuring and functioning in 6d- and 21d-old biofilms. •A difference of 2.5 °C produced contrasted denitrifier communities. •The indirect temperature effect on denitrification activity shifted between biofilm age. •Warming impact strongly depends on the bacterial successional trajectory.

  14. Warming-induced changes in denitrifier community structure modulate the ability of phototrophic river biofilms to denitrify

    International Nuclear Information System (INIS)

    Microbial denitrification is the main nitrogen removing process in freshwater ecosystems. The aim of this study was to show whether and how water warming (+ 2.5 °C) drives bacterial diversity and structuring and how bacterial diversity affects denitrification enzymatic activity in phototrophic river biofilms (PRB). We used water warming associated to the immediate thermal release of a nuclear power plant cooling circuit to produce natural PRB assemblages on glass slides while testing 2 temperatures (mean temperature of 17 °C versus 19.5 °C). PRB were sampled at 2 sampling times during PRB accretion (6 and 21 days) in both temperatures. Bacterial community composition was assessed using ARISA. Denitrifier community abundance and denitrification gene mRNA levels were estimated by q-PCR and qRT-PCR, respectively, of 5 genes encoding catalytic subunits of the denitrification key enzymes. Denitrification enzyme activity (DEA) was measured by the acetylene-block assay at 20 °C. A mean water warming of 2.5 °C was sufficient to produce contrasted total bacterial and denitrifier communities and, therefore, to affect DEA. Indirect temperature effect on DEA may have varied between sampling time, increasing by up to 10 the denitrification rate of 6-day-old PRB and decreasing by up to 5 the denitrification rate of 21-day-old PRB. The present results suggest that indirect effects of warming through changes in bacterial community composition, coupled to the strong direct effect of temperature on DEA already demonstrated in PRB, could modulate dissolved nitrogen removal by denitrification in rivers and streams. - Highlights: •We produced river biofilms in 2 mean temperature conditions: 17 vs 19.5 °C. •We compared their denitrifiers' structuring and functioning in 6d- and 21d-old biofilms. •A difference of 2.5 °C produced contrasted denitrifier communities. •The indirect temperature effect on denitrification activity shifted between biofilm age. •Warming impact strongly depends on the bacterial successional trajectory

  15. Cr(VI) reduction under aerobic and denitrifying conditions by an aquifer-derived Pseudomonad

    Science.gov (United States)

    Beller, H. R.; Han, R.; Geller, J. T.

    2009-12-01

    Chromium contamination of groundwater is widespread within the Department of Energy (DOE) complex. For example, at DOE’s Hanford 100 Area in Washington state, the volume of Cr-contaminated groundwater is estimated to be 1.5 billion gallons. Bioremediation (in situ reductive immobilization) studies involving injection of a lactate-containing polymer have been conducted in the Hanford 100H area, where we have observed sequential use of the dissolved electron acceptors present in groundwater, namely, oxygen, nitrate, and sulfate. As part of an effort to explore Cr(VI) reduction under relevant electron-accepting conditions and with relevant bacteria, we have conducted studies with strain RCH2, a denitrifying bacterium similar to Pseudomonas stutzeri that was isolated from the Hanford 100H aquifer. Cell suspension studies with lactate demonstrated that Cr(VI) reduction could occur under either denitrifying or aerobic conditions (at comparable rates), and that reduction was much more rapid when the terminal electron acceptor (i.e., nitrate or O2) was present. It appears that, under both aerobic and denitrifying conditions, the chromate reductase gene(s) are not inducible by Cr; this conclusion is based on the fact that these cell suspension studies were conducted with cells grown in the absence of Cr and resuspended in a buffer that included chloramphenicol, which inhibits protein synthesis. As our studies indicate that anaerobic Cr(VI) reduction by strain RCH2 is much more rapid in the presence of nitrate (i.e., during denitrification) than in its absence, we explored molecular methods that could readily assess in situ denitrification. Specifically, we investigated whether the gene and transcript copy number of diagnostic denitrification genes (nirS and narG) in groundwater could be used to estimate in situ denitrification rates. Continuous culture (chemostat) studies showed strong correlations (r2 values > 0.93) between denitrification rate and either nirS or narG transcript copy number, suggesting that monitoring expression of such genes (and relevant chromate reductase genes, when characterized) in groundwater could provide valuable information for understanding the biogeochemical dynamics of in situ chromate reduction.

  16. Molecular and Stable Isotope Investigation of Nitrite Respiring Bacterial Communities Capable of Anaerobic Ammonium Oxidation (ANAMMOX) and Denitrifying Anaerobic Methane Oxidation (DAMO) in Nitrogen Contaminated Groundwater

    Science.gov (United States)

    Song, B.; Hirsch, M.; Taylor, J.; Smith, R. L.; Repert, D.; Tobias, C. R.

    2010-12-01

    Anaerobic ammonium oxidation (ANAMMOX) and denitrifying anaerobic methane oxidation (DAMO) are two recently discovered N2 production pathways in the microbial nitrogen cycle. ANAMMOX has been relatively well investigated in various aquatic ecosystems, while DAMO has been examined only in freshwater wetlands. However, neither ANAMMOX nor DAMO have been studied in groundwater ecosystems as microbial N removal processes where they could compliment or compete with denitrification to remediate N contaminated aquifers. Thus, we conducted molecular and stable isotope analyses to detect and measure ANAMMOX and DAMO in a nitrogen contaminated aquifer on Cape Cod, Massachusetts. The study site has a plume of nitrogen contaminated groundwater as a result of continuous discharge of treated wastewater over 60 years. Groundwater was collected from multiport sampling devices installed at two sites, near the waste-water disposal location (A) and more than 3 km down gradient (B) along the contamination plume. Biomass was collected from water samples for DNA extraction and 15N tracer incubation experiments. PCR with specific 16S rRNA gene primers detected the presence of ANAMMOX and DAMO bacteria at both sites. Phylogenetic analysis of 16S rRNA genes revealed that the ANAMMOX community at site A was most associated with Kuenenia spp. while site B had a community more closely related to Brocadia spp. The DAMO communities at the two sites were quite different based on 16S rRNA gene analysis. The communities at site B are closely associated with Candidatus “Methylomirabilis oxyfera”, which is the first enriched DAMO culture. Most of the 16S rRNA sequences detected in site A were related to those found in other DAMO enrichment cultures established from a eutrophic ditch sediment. In order to determine active members of ANAMMOX communities, the transcriptional expression of hydrazine oxidase (hzo) and hydrazine hydrolase (hh) genes was examined at both sites. In addition, 15N tracer incubation experiments were used to measure the rates of ANAMMOX and denitrification. ANAMMOX was found to be higher than denitrification at site A where ANAMMOX accounted for 60% of the 15N2 production. In contrast, denitrification was higher than ANAMMOX at site B where Methylomirabilis spp. were found. Thus, this study clearly demonstrates the potential importance of ANAMMOX and DAMO in the nitrogen removal from groundwater and suggests that detailed characterization of the processes under in situ subsurface conditions could provide new information regarding the ecology of these microbes.

  17. Dynamics of Soil Denitrifier Populations: Relationships between Enzyme Activity, Most-Probable-Number Counts, and Actual N Gas Loss †

    OpenAIRE

    Martin, Kendall; Parsons, Laura L.; Murray, Robert E.; Smith, M. Scott

    1988-01-01

    To better understand temporal variability in soil denitrification, denitrifying enzyme activity (DEA) and denitrifier populations (as determined by most-probable-number [MPN] counts) were measured in field and laboratory experiments. Measurements of DEA and MPN provided highly contradictory indications of denitrifier dynamics. In laboratory incubations, under conditions favoring active denitrification, the synthesis of new denitrifying enzymes and the actual amount of denitrification were clo...

  18. Cultivo del nematodo Panagrellus redivivus (Goodey, 1945) en un medio de avena enriquecida con Spirulina sp. / Nematode culture of Panagrellus redivivus (Goodey, 1945) with Spirulina sp. - enriched oatmeal

    Scientific Electronic Library Online (English)

    Ramón, de Lara; Thalía, Castro; Jorge, Castro; Germán, Castro.

    2007-04-01

    Full Text Available El nematodo Panagrellus redivivus se cultivó en dos medios: uno con hojuelas de avena y otro con hojuelas de avena enriquecido con Spirulina sp., en recipientes de plástico de 15x15x5 cm de altura con 200 g de hojuela de avena y 300 mL de agua purificada. Se utilizaron 5 g de Spirulina en el medio. [...] Se utilizó el programa SYSTAT versión 10.2 para el análisis estadístico; para determinar las diferencias significativas entre los tratamientos, se usó un análisis de varianza unidireccional (ANDEVA) con una confiabilidad ?= 0,05. Los resultados obtenidos muestran que el crecimiento de las poblaciones de nematodos en el medio enriquecido con Spirulina presentó la mayor abundancia de individuos a la segunda semana del cultivo, mientras que la población que creció en el medio de avena, presentó su mayor registro a la quinta semana del cultivo y no alcanzó el número de organismos que tuvo la población cultivada en el medio con Spirulina. El contenido de aminoácidos de las poblaciones de ambos medios se comparó y se cotejaron con los reportados para Artemia alimentada con Spirulina, observándose que en la mayoría de los aminoácidos las cantidades fueron mayores en P. redivivus cultivado en el medio con Spirulina. La composición de ácidos grasos en los nematodos cultivados en ambos medios presentó diferencias significativas entre los ácidos grasos linoleico, araquidónico y eicosapentenoico los cuales fueron en mayor porcentaje que los reportados en P. redivivus cultivado en avena con aceite de girasol. Estos datos demuestran que la cianobacteria Spirulina sp. acelera el crecimiento de la población del nematodo y permite la presencia de aminoácidos y ácidos grasos, y hace que estos nematodos puedan cubrir los requerimientos nutritivos de larvas de peces dulceacuícolas, sin embargo, se requieren estudios que lo demuestren Abstract in english The nematode Pangrellus redivivus was cultured in two media: one with oat flakes and the other with Spirulina sp.-enriched oat flakes, in 15x15x5 cm plastic containers with 200 g oat flakes and 300 mL purified water. Five grams of Spirulina was used in the medium. SYSTAT version 10.2 was used for st [...] atistical analysis; to determine the significant differences between treatment a unidirectional analysis of variance (ANOVA) was used with a confidence level of ?= 0.05. The results show that growth of the nematode population in the Spirulina-enriched medium presented the highest abundance of individuals on the second week of culture, whereas the population grown in the oat flakes medium showed the highest abundance on the fifth week of culture and did not reach the number of organisms attained by the population cultured in the Spirulina-enriched medium. The amino acids content of the populations from both media were compared to those reported for Artemia fed with Spirulina, observing that the amounts were higher for most amino acids in P. redivivus cultured in the Spirulina-enriched medium. The composition of fatty acids in the nematode cultures in both media depicted significant differences for the linoleic, arachidonic, and eicosapentaenoic fatty acids, which were found in a higher percentage than reported for P. redivivus cultures in oat flakes supplemented with sunflower oil. These data reveal that the cyanobacterium Spirulina sp. accelerates growth of the nematode populations and allows the presence of amino and fatty acids, making these nematodes suitable to cover the nutritional requirements of freshwater fish larvae, but further studies are needed to demonstrate it

  19. Interactions of deoxynivalenol and lipopolysaccharides on cytotoxicity protein synthesis and metabolism of DON in porcine hepatocytes and Kupffer cell enriched hepatocyte cultures.

    Science.gov (United States)

    Döll, Susanne; Schrickx, Jan A; Valenta, Hana; Dänicke, Sven; Fink-Gremmels, Johanna

    2009-09-10

    The cytotoxicity of deoxynivalenol (DON), effects on protein synthesis and albumin secretion was investigated in porcine hepatocytes and Kupffer cell-enriched hepatocyte cultures (co-cultures) in the presence and absence of lipopolysaccharides (LPS). Up to 16microM DON did not reduce the metabolic activity of hepatocytes. Lysosomal activity reacted more sensitively as neutral red uptake was decreased starting at 2 or 4microM DON irrespective of LPS exposure. The synthesis of secreted proteins was reduced to 31% and 42%, and of cellular proteins to 47% and 39%, in the absence and presence of LPS, respectively, when hepatocytes were exposed to 2microM DON. Reduced albumin secretion in response to DON was already observed after 3h in hepatocytes as well as co-cultures while LPS-mediated decrease was not evident until 24h, when interactions between DON and LPS resulted from a diminishing difference between LPS stimulated and non-stimulated cultures with increasing concentrations of DON. All observed effects may be biased by the cells' ability to conjugate DON to glucuronic acid as 54% and 64% of DON administered at 5nM were recovered as conjugates after 48h. Glucuronidation rate, as well as total DON recovery, decreased with increasing concentrations of DON, giving rise to assumptions on the formation of undetected metabolites. PMID:19477247

  20. Interactions of deoxynivalenol and lipopolysaccharides on cytokine excretion and mRNA expression in porcine hepatocytes and Kupffer cell enriched hepatocyte cultures.

    Science.gov (United States)

    Döll, Susanne; Schrickx, Jan A; Dänicke, Sven; Fink-Gremmels, Johanna

    2009-10-01

    The effects of deoxynivalenol (DON) on the mRNA expression of cytokines and inflammation-related genes, as well as the cytokine secretion of porcine hepatocytes and Kupffer cell enriched hepatocyte cultures (co-cultures), were investigated in the absence or presence of LPS. DON and LPS acted in a synergistic manner with regard to a significantly increased mRNA expression of TNF-alpha in hepatocytes exposed to 500 nM or 2000 nM DON, or non-significant increase in co-cultures after 3h of exposure. TNF-alpha supernatant concentrations were increased due to LPS but did not reflect the synergistic effects with DON as observed at mRNA level. IL-6 mRNA in hepatocyte cultures at 6h paralleled the TNF-alpha supernatant pattern at this time point. In co-cultures and hepatocytes, a DON dose dependent induction of IL-6 mRNA was detected in cells not exposed to LPS. Supernatant concentrations of LPS-induced IL-6 were significantly decreased by 2000 nM DON in both types of cell cultures. Also the mRNA expression of the anti-inflammatory IL-10 was increased by DON to various degrees depending on DON-dose, stimulation with LPS and time point of measurement. After 6h, expression of iNOS was only induced by 2000 nM DON, but not in LPS treated cells. Even if mRNA induction was not paralleled by related supernatant concentrations of TNF-alpha, IL-6 and IL-10 under the conditions of the present investigations, it was clearly demonstrated that DON has the potential to provoke and modulate immunological reactions of porcine liver cells. PMID:19607891

  1. Chloramphenicol Inhibition of Denitrifying Enzyme Activity in Two Agricultural Soils

    OpenAIRE

    Murray, Robert E.; Knowles, Roger

    1999-01-01

    Chloramphenicol, at concentrations greater than 0.1 g/liter (0.3 mM), inhibited the denitrifying enzyme activity (DEA) of slurries of humisol and sandy loam soils by disrupting the activity of existing nitrate reductase enzymes. When the concentration of chloramphenicol was increased from 0.1 to 2.0 g/liter (6.0 mM), the rate of nitrite production from nitrate decreased by 25 to 46%. The rate of NO production from nitrate decreased by 20 to 39%, and the rate of N2O production from nitrate, in...

  2. Rapid in vitro regeneration method for Moringa oleifera and performance evaluation of field grown nutritionally enriched tissue cultured plants

    OpenAIRE

    R. K. Saini; Shetty, N.P.; Giridhar, P; Ravishankar, G. A.

    2012-01-01

    The present investigations were attempted to develop the rapid in vitro micropropagation protocol of Moringa oleifera (Variety-PKM-1) from nodal sections of young, aseptically grown seedlings. Benzyladenine (BA) at 4.44 ?M was found to be optimal in producing on maximum an average of 9.0 ± 1.0 axillary shoots per explant after 15 days of inoculation. A high multiplication rate was established through routine sub culturing of nodal sections explanted from in vitro shoot cultures. In vitro root...

  3. Effects of Temperature on Denitrifying Growth and Nitrate Reduction End Products of Comamonas testosteroni Isolated from Estuarine Sediment

    Directory of Open Access Journals (Sweden)

    IMAN RUSMANA

    2007-01-01

    Full Text Available Predictions of seasonal changes in N2O emission that occur in natural estuaries are important to anticipate the future implications of global warming. This study showed the effect of temperature on denitrifying growth and nitrate reduction end product of Comamonas testoteroni isolated from estuarine sediment using both batch and continuous cultures. The ?max values of Comamonas testosteroni grown in anaerobic batch culture were increased with increasing temperature, and the highest ?max was found at 26 °C. Concentrations of nitrate reduced (mg-1 dried weight cells were higher at low temperature. Concentrations of N2 produced were higher at low temperature and the production of N2 was higher than both NO2- and N2O productions

  4. Complete genome sequence of Methylophilus sp. TWE2 isolated from methane oxidation enrichment culture of tap-water.

    Science.gov (United States)

    Xia, Fei; Zou, Bin; Shen, Cong; Zhu, Ting; Gao, Xin-Hua; Quan, Zhe-Xue

    2015-10-10

    The non-methane-utilizing methylotroph, Methylophilus sp. TWE2, was isolated from tap-water during the enrichment of methanotrophs with methane. The complete genome sequence of strain TWE2 showed that this bacterium may convert methanol to formaldehyde via catalysis of methanol dehydrogenase (MDH), after which formaldehyde would be assimilated to biomass through the ribulose monophosphate (RuMP) pathway or dissimilated via the tetrahydromethanopterin (H4MPT) pathway. The deficiency of glycolysis and the TCA cycle indicate that strain TWE2 may be an obligate methylotroph. This is the first complete genome sequence of the genus Methylophilus. PMID:26253961

  5. Thermo-acidophillic biohydrogen production from rice bran de-oiled wastewater by Selectively enriched mixed culture

    OpenAIRE

    D.Sivaramakrishna, D.Sreekanth, V.Himabindu, M.Lakshmi Narasu

    2010-01-01

    The present study focuses on the biohydrogen production in an anaerobic batch reactor operated at thermophillic (570C) and acidophilic conditions (pH 6) with rice bran de-oiled wastewater (RBOW) as substrate. The hydrogen generating mixed microflora was enriched from slaughter house sludge (SHS) through acid treatment (pH 3-4, for 24h) coupled with heat treatment (1h at 1000C) to eliminate non-spore forming bacteria and to inhibit the growth of methanogenic bacteria (MB) prior to inoculation ...

  6. A Fungal Cytochrome P-450nor Confers Denitrifying Ability to Tobacco By-2 Cells

    Directory of Open Access Journals (Sweden)

    Babiker M.A. Abdel-Banat

    2008-01-01

    Full Text Available Reactive nitrogen gases progressively contribute to the global warming. Development of gas-gas denitrifying plants that can efficiently reduce reactive nitrogen gases to dinitrogen (N2 could help to mitigate the effect of these gases. Taking the advances in gene manipulation technology, tobacco BY-2 cells were transformed with the fungus Cylindrocarpon tonkinense cytochrome P-450nor2 (Cnor2 gene. The product of this gene acts as nitric oxide reductase (nor. Transgenic BY-2 cell clones cultured in 15N-labelled nitrate (15NO3- actively evolved 15N2O gas up to 35-folds compared to the wild-type cells. In 15N-labelled ammonium (15NH4+, the transgenic and wild-type cells produced comparable amounts of 15N2O. This indicates that ammonium is not a direct substrate for nor and the small amount of N2O observed may be due to the nitrification of ammonium to nitrite. Addition of tungstate (a nitrate reductase inhibitor and cyanide to the transgenic cell cultures strongly inhibited 15N2O production. Activity of nor enzyme was also confirmed by in vitro activity assay. These observations together suggest that Cnor2 is actively expressed and enhanced the reduction of nitrate to N2O in plant cells. This finding indicates that plant cells are capable to tackle the denitrification pathway.

  7. Aerobic and anaerobic growth of rifampin-resistant denitrifying bacteria in soil.

    OpenAIRE

    Murray, R E; Parsons, L L; Smith, M.S.

    1990-01-01

    The growth and survival of several rifampin-resistant isolates of denitrifying bacteria were examined under anaerobic (denitrifying) and aerobic conditions. Two isolates added to nonsterile Bruno soil at densities of between 10(4) and 10(6) CFU g dry soil-1 exhibited an initial period of growth followed by a gradual decline in numbers. After 28 days, both isolates maintained viable populations of between 10(4) and 10(5) CFU g dry soil-1 under both denitrifying and aerobic conditions. One of t...

  8. Stable Carbon Isotope Fractionation During 1,2-Dichloropropane-to-Propene Transformation by an Enrichment Culture Containing Dehalogenimonas Strains and a dcpA Gene.

    Science.gov (United States)

    Martín-González, L; Mortan, S Hatijah; Rosell, M; Parladé, E; Martínez-Alonso, M; Gaju, N; Caminal, G; Adrian, L; Marco-Urrea, E

    2015-07-21

    A stable enrichment culture derived from Besòs river estuary sediments stoichiometrically dechlorinated 1,2-dichloropropane (1,2-DCP) to propene. Sequential transfers in defined anaerobic medium with the inhibitor bromoethanesulfonate produced a sediment-free culture dechlorinating 1,2-DCP in the absence of methanogenesis. Application of previously published genus-specific primers targeting 16S rRNA gene sequences revealed the presence of a Dehalogenimonas strain, and no amplification was obtained with Dehalococcoides-specific primers. The partial sequence of the 16S rRNA amplicon was 100% identical with Dehalogenimonas alkenigignens strain IP3-3. Also, dcpA, a gene described to encode a corrinoid-containing 1,2-DCP reductive dehalogenase was detected. Resistance of the dehalogenating activity to vancomycin, exclusive conversion of vicinally chlorinated alkanes, and tolerance to short-term oxygen exposure is consistent with the hypothesis that a Dehalogenimonas strain is responsible for 1,2-DCP conversion in the culture. Quantitative PCR showed a positive correlation between the number of Dehalogenimonas 16S rRNA genes copies in the culture and consumption of 1,2-DCP. Compound specific isotope analysis revealed that the Dehalogenimonas-catalyzed carbon isotopic fractionation (?C(bulk)) of the 1,2-DCP-to-propene reaction was -15.0 ± 0.7‰ under both methanogenic and nonmethanogenic conditions. This study demonstrates that carbon isotope fractionation is a valuable approach for monitoring in situ 1,2-DCP reductive dechlorination by Dehalogenimonas strains. PMID:26111261

  9. Effects of resveratrol on enrichment of adipose-derived stem cells and their differentiation to osteoblasts in two-and three-dimensional cultures.

    Science.gov (United States)

    Erdman, Christopher P; Dosier, Christopher R; Olivares-Navarrete, Rene; Baile, Clifton; Guldberg, Robert E; Schwartz, Zvi; Boyan, Barbara D

    2012-12-01

    The goal of this study was to develop a method for increasing the yield of multipotent adipose-derived mesenchymal stem cells (ASCs) and osteoprogenitor cells (OPCs) from subcutaneous fat. After removing mature adipocytes and haematopoietic cells from rat inguinal fat, ASCs in the remaining cell population were verified by their attachment to plastic, surface marker profile (CD271(+), CD73(+) and CD45(-)) and ability to differentiate into adipocytes, chondrocytes and osteoblasts. OPCs were defined as E11(+) and OCN(+). Adherent cells were cultured in growth medium (GM) or osteogenic medium (OM) and treated with resveratrol (0, 12.5, and 25 µM) for 7 days; ASCs and OPCs were assessed by flow cytometry. Osteogenic potential was determined in two-dimensional (2D) cultures as a function of alkaline phosphatase-specific activity and osteocalcin production. In addition, cells were seeded onto three-dimensional (3D) poly-?-caprolactone scaffolds and cultured under dynamic conditions; mineralization was quantified by micro-CT at 4, 8 and 12 weeks. Resveratrol increased the percentage of ASCs in the population (population%) and number of ASCs in both GM and OM, but increased only the number of OPCs in GM. In both media types resveratrol increased alkaline phosphatase activity and osteocalcin levels. In 3D cultures, resveratrol-treated cells significantly increased mineralized matrix volume at early time points. Resveratrol exerted a biphasic effect on adherent cells by enriching the ASC and OPC populations and enhancing osteogenic differentiation. Resveratrol pretreatment induced more mineralization at earlier time points and represents a clinically viable technique for orthopaedic and dental applications for autologous stem cell therapy. PMID:22467433

  10. Determination of the cause of the symptoms on yellow yam (Dioscorea cayenensis Lam.) leaf tissue and their eradication, enriching the culture medium and using techniques of meristem culture, thermo and chemotherapy on in vitro conditions

    International Nuclear Information System (INIS)

    Yams (Dioscorea spp) has been cultivated for exportation in Costa Rica, in North Huetar region. In vitro culture technique has been used for multiplying planting material for many advantages. However, cleaning of viruses that affect has been ineffective. Viruses such as: the potyvirus, potexvirus, cucumovirus . Methods like meristem culture, chemotherapy, thermotherapy and combinations of these have been used for the elimination of virus in plant species. The plants were evaluated in indexing assays, observing symptoms, serological methods and electron microscopy, among others. Other problems that have been affecting in vitro plant are deficient culture media in some nutrient. The presence of some abnormal characteristics in leaf tissue was determined whether have been caused by a virus or a nutritional deficiency in the culture medium. The presence of the virus has tried to find using ELISA and electron microscopy. Tests meristem culture, thermotherapy and chemotherapy have been made for the eradication of a possible virus; which have been assessed by observation of symptomatology and ELISA. The efficiency of the culture medium was evaluated to enrich it with nitrogen or excess iron. None of the suspected virus found in ELISA tests. Filaments are presumably viral particles were found through analysis of ultrastructure, as well as alterations in chloroplasts which indicated the presence of a pathogen or toxicity. Thermotherapy and chemotherapy with the concentration of 40 mg/L of ribavirin have been the most effective for the elimination of symptoms in virus eradication treatments. Assessments nutrient concentrations have shown that the differences between the various treatments used were undetectable. The symptoms presented were caused, according to the conclusions, by a virus which should preferably deal with thermotherapy. (author)

  11. Greenhouse Gas Emission from In-situ Denitrifying Bioreactors

    Science.gov (United States)

    Pluer, W.; Walter, M. T.; Geohring, L.

    2013-12-01

    Despite decades of concerted effort to mitigate nonpoint source nitrate (NO3-) pollution from agricultural lands, these efforts have not been sufficient to arrest eutrophication, which continues to be a serious and chronic problem. Two primary processes for removing excess NO3- from water are biological assimilation and denitrification. Denitrifying bacteria use NO3- as the electron acceptor for respiration in the absence of oxygen. Denitrification results in reduced forms of nitrogen, often dinitrogen gas (N2) but also nitrous oxide (N2O), an aggressive greenhouse gas (GHG). A promising solution to NO3- pollution is to intercept agricultural discharges with denitrifying bioreactors (DNBRs), though research has been limited to NO3- level reduction and omitted process mechanisms. DNBRs work by providing an anaerobic environment with plenty of organic matter (commonly woodchips) for denitrifying bacteria to flourish. While, initial results from bioreactor studies show that they can cost-effectively remove NO3-, GHG emission could be an unintended consequence. The study's goal is to determine how bioreactor design promotes microbial denitrification while limiting N2O production. It specifically focuses on expanding the body of knowledge concerning DNBRs in the areas of design implications and internal processes by measuring intermediate compounds and not solely NO3-. Nutrient samples are collected at inflow and outflow structures and tested for NO3- and nitrite (NO2-). Dissolved and headspace gas samples are collected and tested for N2O. Additional gas samples will be analyzed for naturally-occurring isotopic N2 to support proposed pathways. Designs will be analyzed both through the N2O/N2 production ratio and NO2- production caused by various residence times and inflow NO3- concentrations. High GHG ratios and NO2- production suggest non-ideal conditions or flow patterns for complete denitrification. NO3- reduction is used for comparison with previous studies. Few studies have focused on the reactions and products of DNBRs and instead note NO3- reductions in outflows as evidence that this should be used to treat agricultural discharges. It is, however, critical to understand all of the potential impacts that this treatment solution may have, which means identifying processes and design specifications that may affect them. This study addresses this lack of mechanistic understanding of DNBRs by means of sampling for incomplete products. Results will quantify gaseous products and internal processes and present a more complete picture of the potential for widespread use of DNBRs.

  12. Thermo-acidophillic biohydrogen production from rice bran de-oiled wastewater by Selectively enriched mixed culture

    Energy Technology Data Exchange (ETDEWEB)

    Sivaramakrishna, D.; Sreekanth, D.; Himabindu, V. [Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Kukatpally Hyderabad-500 085 (India); Narasu, M. Lakshmi [Centre for Biotechnology, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Kukatpally Hyderabad-500 085 (India)

    2010-07-01

    The present study focuses on the biohydrogen production in an anaerobic batch reactor operated at thermophillic (570C) and acidophilic conditions (pH 6) with rice bran de-oiled wastewater (RBOW) as substrate. The hydrogen generating mixed microflora was enriched from slaughter house sludge (SHS) through acid treatment (pH 3-4, for 24h) coupled with heat treatment (1h at 1000C) to eliminate non-spore forming bacteria and to inhibit the growth of methanogenic bacteria (MB) prior to inoculation in the reactor. The hydrogen production rate was maximum at 570C (1861 +- 14ml/L-WW/d) compared to 370C (651 +- 30ml/L-ww/d). The Hydrogen yield increased with temperature from 1.1 to 2.2 molH2/mol of substrate respectively. The optimum pH range for hydrogen production in this system was observed in between 5.5 to 6. Acid-forming pathway with butyric acid as a major metabolite dominated the metabolic flow during the hydrogen production.

  13. Thermo-acidophillic biohydrogen production from rice bran de-oiled wastewater by Selectively enriched mixed culture

    Directory of Open Access Journals (Sweden)

    D.Sivaramakrishna, D.Sreekanth, V.Himabindu, M.Lakshmi Narasu

    2010-07-01

    Full Text Available The present study focuses on the biohydrogen production in an anaerobic batch reactor operated at thermophillic (570C and acidophilic conditions (pH 6 with rice bran de-oiled wastewater (RBOW as substrate. The hydrogen generating mixed microflora was enriched from slaughter house sludge (SHS through acid treatment (pH 3-4, for 24h coupled with heat treatment (1h at 1000C to eliminate non-spore forming bacteria and to inhibit the growth of methanogenic bacteria (MB prior to inoculation in the reactor. The hydrogen production rate was maximum at 570C (1861±14ml/L-WW/d compared to 370C (651±30ml/L-ww/d. The Hydrogen yield increased with temperature from 1.1 to 2.2 molH2/mol of substrate respectively. The optimum pH range for hydrogen production in this system was observed in between 5.5 to 6. Acid-forming pathway with butyric acid as a major metabolite dominated the metabolic flow during the hydrogen production.

  14. Bacterial diversity of autotrophic enriched cultures from remote, glacial Antarctic, Alpine and Andean aerosol, snow and soil samples

    Directory of Open Access Journals (Sweden)

    E. González-Toril

    2009-01-01

    Full Text Available Four different communities and one culture of autotrophic microbial assemblages were obtained by incubation of samples collected from high elevation snow in the Alps (Mt. Blanc area and the Andes (Nevado Illimani summit, Bolivia, from Antarctic aerosol (French station Dumont d'Urville and a maritime Antarctic soil (King George Island, South Shetlands, Uruguay Station Artigas, in a minimal mineral (oligotrophic media. Molecular analysis of more than 200 16S rRNA gene sequences showed that all cultured cells belong to the Bacteria domain. Phylogenetic comparison with the currently available rDNA database allowed sequences belonging to Proteobacteria Alpha-, Beta- and Gamma-proteobacteria, Actinobacteria and Bacteroidetes phyla to be identified. The Andes snow culture was the richest in bacterial diversity (eight microorganisms identified and the marine Antarctic soil the poorest (only one. Snow samples from Col du Midi (Alps and the Andes shared the highest number of identified microorganisms (Agrobacterium, Limnobacter, Aquiflexus and two uncultured Alphaproteobacteria clones. These two sampling sites also shared four sequences with the Antarctic aerosol sample (Limnobacter, Pseudonocardia and an uncultured Alphaproteobacteriaclone. The only microorganism identified in the Antarctica soil (Brevundimonas sp. was also detected in the Antarctic aerosol. Most of the identified microorganisms had been detected previously in cold environments, marine sediments soils and rocks. Air current dispersal is the best model to explain the presence of very specific microorganisms, like those identified in this work, in environments very distant and very different from each other.

  15. Enrichment of denitrifying phosphorus accumulating organisms (DPAOs) in a continuous flow laboratory scale plant

    International Nuclear Information System (INIS)

    Enhanced Biological Phosphate Removal (EBPR) is a well established method for efficient removal of phosphate during wastewater treatment by using biological instead of chemical phenomena. EBPR is currently implemented at a number of Waste Water Treatment Plants (WWTPs) and usually phosphate removal occurs by recirculating activated sludge between an anaerobic and a aerobic tank. (Author)

  16. Nitrogen removal from micro-polluted reservoir water by indigenous aerobic denitrifiers.

    Science.gov (United States)

    Huang, Ting-Lin; Zhou, Shi-Lei; Zhang, Hai-Han; Zhou, Na; Guo, Lin; Di, Shi-Yu; Zhou, Zi-Zhen

    2015-01-01

    Treatment of micro-polluted source water is receiving increasing attention because of environmental awareness on a global level. We isolated and identified aerobic denitrifying bacteria Zoogloea sp. N299, Acinetobacter sp. G107, and Acinetobacter sp. 81Y and used these to remediate samples of their native source water. We first domesticated the isolated strains in the source water, and the 48-h nitrate removal rates of strains N299, G107, and 81Y reached 33.69%, 28.28%, and 22.86%, respectively, with no nitrite accumulation. We then conducted a source-water remediation experiment and cultured the domesticated strains (each at a dry cell weight concentration of 0.4 ppm) together in a sample of source water at 20-26 °C and a dissolved oxygen concentration of 3-7 mg/L for 60 days. The nitrate concentration of the system decreased from 1.57 ± 0.02 to 0.42 ± 0.01 mg/L and that of a control system decreased from 1.63 ± 0.02 to 1.30 ± 0.01 mg/L, each with no nitrite accumulation. Total nitrogen of the bacterial system changed from 2.31 ± 0.12 to 1.09 ± 0.01 mg/L, while that of the control system changed from 2.51 ± 0.13 to 1.72 ± 0.06 mg/L. The densities of aerobic denitrification bacteria in the experimental and control systems ranged from 2.8 × 10(4) to 2 × 10(7) cfu/mL and from 7.75 × 10(3) to 5.5 × 10(5) cfu/mL, respectively. The permanganate index in the experimental and control systems decreased from 5.94 ± 0.12 to 3.10 ± 0.08 mg/L and from 6.02 ± 0.13 to 3.61 ± 0.11 mg/L, respectively, over the course of the experiment. Next, we supplemented samples of the experimental and control systems with additional bacteria or additional source water and cultivated the systems for another 35 days. The additional bacteria did little to improve the water quality. The additional source water provided supplemental carbon and brought the nitrate removal rate in the experimental system to 16.97%, while that in the control system reached only 3.01%, with no nitrite accumulation in either system. Our results show that aerobic denitrifying bacteria remain highly active after domestication and demonstrate the applicability of such organisms in the bioremediation of oligotrophic ecosystems. PMID:25867475

  17. Combining Denitrifying Bacteria and Laser Spectroscopy for Isotopic Analyses (?(15)N, ?(18)O) of Dissolved Nitrate.

    Science.gov (United States)

    Soto, David X; Koehler, Geoff; Hobson, Keith A

    2015-07-21

    We present a novel approach for nitrogen (?(15)N) and oxygen (?(18)O) isotopic analysis of nitrate in water based on the isotopic analysis of N2O produced from the conversion of NO3(-) by cultured denitrifying bacteria and off-axis integrated cavity output spectroscopy (OA-ICOS). The headspace N2O was manually injected into an OA-ICOS isotopic N2O laser analyzer through a syringe septum port. Sample analysis time was ?300 s. The use of OA-ICOS technology yields accurate and precise ?(15)N and ?(18)O results for dissolved nitrate samples when nonlinearity issues are considered. This new isotope analytical technique thus improves the isotopic analysis of nitrates by (i) providing accurate measurements of ?(15)N and ?(18)O without preconcentration, (ii) eliminating interferences by other gas substances (i.e., H2O and CO2), and (iii) reducing extensive maintenance and costs of isotope ratio mass spectrometers (IRMS). This approach will greatly streamline the identification and quantification of nitrate sources in aquatic systems. PMID:26151723

  18. Aerobic and anaerobic degradation of a range of alkyl sulfides by a denitrifying marine bacterium

    Science.gov (United States)

    Visscher, P.T.; Taylor, B.F.

    1993-01-01

    A pure culture of a bacterium was obtained from a marine microbial mat by using an anoxic medium containing dimethyl sulfide (DMS) and nitrate. The isolate grew aerobically or anaerobically as a denitrifier on alkyl sulfides, including DMS, dimethyl disulfide, diethyl sulfide (DES), ethyl methyl sulfide, dipropyl sulfide, dibutyl sulfide, and dibutyl disulfide. Cells grown on an alkyl sulfide or disulfide also oxidized the corresponding thiols, namely, methanethiol, ethanethiol, propanethiol, or butanethiol. Alkyl sulfides were metabolized by induced or derepressed cells with oxygen, nitrate, or nitrite as electron acceptor. Cells grown on DMS immediately metabolized DMS, but there was a lag before DES was consumed; with DES-grown cells, DES was immediately used but DMS was used only after a lag. Chloramphenicol prevented the eventual use of DES by DMS-grown cells and DMS use by DES-grown cells, respectively, indicating separate enzymes for the metabolism of methyl and ethyl groups. Growth was rapid on formate, acetate, propionate, and butyrate but slow on methanol. The organism also grew chemolithotrophically on thiosulfate with a decrease in pH; growth required carbonate in the medium. Growth on sulfide was also carbonate dependent but slow. The isolate was identified as a Thiobacillus sp. and designated strain ASN-1. It may have utility for removing alkyl sulfides, and also nitrate, nitrite, and sulfide, from wastewaters.

  19. Methyl t-Butyl Ether Mineralization in Surface-Water Sediment Microcosms under Denitrifying Conditions

    Science.gov (United States)

    Bradley, P.M.; Chapelle, F.H.; Landmeyer, J.E.

    2001-01-01

    Mineralization of [U-14C] methyl t-butyl ether (MTBE) to 14CO2 without accumulation of t-butyl alcohol (TBA) was observed in surface-water sediment microcosms under denitrifying conditions. Methanogenic activity and limited transformation of MTBE to TBA were observed in the absence of denitrification. Results indicate that bed sediment microorganisms can effectively degrade MTBE to nontoxic products under denitrifying conditions.

  20. Methyl t-Butyl Ether Mineralization in Surface-Water Sediment Microcosms under Denitrifying Conditions

    OpenAIRE

    Bradley, Paul M.; Chapelle, Francis H.; Landmeyer, James E.

    2001-01-01

    Mineralization of [U-14C]methyl t-butyl ether (MTBE) to 14CO2 without accumulation of t-butyl alcohol (TBA) was observed in surface-water sediment microcosms under denitrifying conditions. Methanogenic activity and limited transformation of MTBE to TBA were observed in the absence of denitrification. Results indicate that bed sediment microorganisms can effectively degrade MTBE to nontoxic products under denitrifying conditions.

  1. A Comparative Study of the Bacterial Community in Denitrifying and Traditional Enhanced Biological Phosphorus Removal Processes

    OpenAIRE

    Lv, Xiao-Mei; Shao, Ming-Fei; Li, Chao-Lin; Li, Ji; Gao, Xin-lei; Sun, Fei-Yun

    2014-01-01

    Denitrifying phosphorus removal is an attractive wastewater treatment process due to its reduced carbon source demand and sludge minimization potential. Two lab-scale sequencing batch reactors (SBRs) were operated in alternating anaerobic-anoxic (A-A) or anaerobic-oxic (A-O) conditions to achieve denitrifying enhanced biological phosphate removal (EBPR) and traditional EBPR. No significant differences were observed in phosphorus removal efficiencies between A-A SBR and A-O SBR, with phosphoru...

  2. Soil Resources Influence Spatial Patterns of Denitrifying Communities at Scales Compatible with Land Management? †

    OpenAIRE

    Enwall, Karin; Throbäck, Ingela N.; Stenberg, Maria; Söderström, Mats; Hallin, Sara

    2010-01-01

    Knowing spatial patterns of functional microbial guilds can increase our understanding of the relationships between microbial community ecology and ecosystem functions. Using geostatistical modeling to map spatial patterns, we explored the distribution of the community structure, size, and activity of one functional group in N cycling, the denitrifiers, in relation to 23 soil parameters over a 44-ha farm divided into one organic and one integrated crop production system. The denitrifiers were...

  3. Identification of active denitrifiers in full-scale nutrient removal wastewater treatment systems

    DEFF Research Database (Denmark)

    McIlroy, Simon Jon; Szyszka, Anna; Starnawski, Piotr Marian; Saunders, Aaron Marc; Nierychlo, Marta; Nielsen, Per Halkjær; Nielsen, Jeppe Lund

    2015-01-01

    Denitrification is essential to the removal of nitrogen from wastewater during treatment, yet an understanding of the diversity of the active denitrifying bacteria responsible in full-scale wastewater treatment plants (WWTP) is lacking. In this study stable isotope probing (SIP) was applied in combination with microautoradiography (MAR)-fluorescence in situ hybridisation (FISH) to identify the active denitrifiers in a full-scale WWTP with biological N and P removal. Recognising that a range of c...

  4. Identification of active denitrifiers in full-scale nutrient removal wastewater treatment systems

    DEFF Research Database (Denmark)

    Mcllroy, Simon; Starnawska, Anna; Starnawski, Piotr; Saunders, Aaron M.; Nierychlo, Marta; Nielsen, Per Halkjær; Nielsen, Jeppe Lund

    2015-01-01

    Denitrification is essential to the removal of nitrogen from wastewater during treatment, yet an understanding of the diversity of the active denitrifying bacteria responsible in full-scale wastewater treatment plants (WWTPs) is lacking. In this study, stable-isotope probing (SIP) was applied in combination with microautoradiography (MAR)-fluorescence in situ hybridization (FISH) to identify previously unrecognized active denitrifying phylotypes in a full-scale WWTP with biological N and P remov...

  5. Heavy metal incorporation in foraminiferal calcite: results from multi-element enrichment culture experiments with Ammonia tepida

    Directory of Open Access Journals (Sweden)

    G.-J. Reichart

    2010-08-01

    Full Text Available The incorporation of heavy metals into carbonate tests of the shallow water benthic foraminifer Ammonia tepida was investigated under controlled laboratory conditions. Temperature, salinity, and pH of the culture solutions were kept constant throughout the duration of this experiment, while trace metal concentrations were varied. Concentrations of Ni, Cu, and Mn were set 5-, 10-, and 20 times higher than levels found in natural North Sea water; for reference, a control experiment with pure filtered natural North Sea water was also analysed. The concentrations of Cu and Ni from newly grown chambers were determined by means of both ?-synchrotron XRF and Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA-ICP-MS. The results of both independent analytical techniques agreed within the analytical uncertainty. In general, the concentration of the analysed elements in the tests increased in line with their concentration in the culture solutions. Potential toxic and/or chemical competition effects might have resulted in the decreased incorporation of Ni and Cu into the calcite of the specimens exposed to the highest elemental concentrations. Mn incorporation exhibited large variability in the experiment with the 20-fold increased element concentrations, potentially due to antagonistic effects with Cu. The partition coefficients of Cu and Ni were calculated to be 0.14 ± 0.02 and 1.0 ± 0.5, respectively, whereas the partition coefficient of Mn was estimated to be least 2.4. These partition coefficients now open the way for reconstructing past concentrations for these elements in sea water.

  6. Analysis of denitrifier community in a bioaugmented sequencing batch reactor for the treatment of coking wastewater containing pyridine and quinoline

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yaohui; Xing, Rui; Wen, Donghui; Tang, Xiaoyan [Peking Univ., Beijing (CN). Key Lab. of Water and Sediment Sciences (Ministry of Education); Sun, Qinghua [Peking Univ., Beijing (CN). Key Lab. of Water and Sediment Sciences (Ministry of Education); Chinese Center for Disease Control and Prevention, Beijing (China). Inst. of Environmental Health and Related Product Safety

    2011-05-15

    The denitrifier community and associated nitrate and nitrite reduction in the bioaugmented and general sequencing batch reactors (SBRs) during the treatment of coking wastewater containing pyridine and quinoline were investigated. The efficiency and stability of nitrate and nitrite reduction in SBR was considerably improved after inoculation with four pyridine- or quinoline-degrading bacterial strains (including three denitrifying strains). Terminal restriction fragment length polymorphism (T-RFLP) based on the nosZ gene revealed that the structures of the denitrifier communities in bioaugmented and non-bioaugmented reactors were distinct and varied during the course of the experiment. Bioaugmentation protected indigenous denitrifiers from disruptions caused by pyridine and quinoline. Clone library analysis showed that one of the added denitrifiers comprised approximately 6% of the denitrifier population in the bioaugmented sludge. (orig.)

  7. Continuous-flow column study of reductive dehalogenation of PCE upon bioaugmentation with the Evanite enrichment culture

    Science.gov (United States)

    Azizian, Mohammad F.; Behrens, Sebastian; Sabalowsky, Andrew; Dolan, Mark E.; Spormann, Alfred M.; Semprini, Lewis

    2008-08-01

    A continuous-flow anaerobic column experiment was conducted to evaluate the reductive dechlorination of tetrachloroethene (PCE) in Hanford aquifer material after bioaugmentation with the Evanite (EV) culture. An influent PCE concentration of 0.09 mM was transformed to vinyl chloride (VC) and ethene (ETH) within a hydraulic residence time of 1.3 days. The experimental breakthrough curves were described by the one-dimensional two-site-nonequilibrium transport model. PCE dechlorination was observed after bioaugmentation and after the lactate concentration was increased from 0.35 to 0.67 mM. At the onset of reductive dehalogenation, cis-dichloroethene (c-DCE) concentrations in the column effluent exceeded the influent PCE concentration indicating enhanced PCE desorption and transformation. When the lactate concentration was increased to 1.34 mM, c-DCE reduction to vinyl chloride (VC) and ethene (ETH) occurred. Spatial rates of PCE and VC transformation were determined in batch-incubated microcosms constructed with aquifer samples obtained from the column. PCE transformation rates were highest in the first 5 cm from the column inlet and decreased towards the column effluent. Dehalococcoides cell numbers dropped from ˜ 73.5% of the total Bacterial population in the original inocula, to about 0.5% to 4% throughout the column. The results were consistent with estimates of electron donor utilization, with 4% going towards dehalogenation reactions.

  8. The social cost of coastal erosion. Using cultural theory to enrich the interpretation of stated preference data.

    Science.gov (United States)

    Kontogianni, A.; Tourkolias, C.; Vousdoukas, M.; Skourtos, M.

    2012-04-01

    Natural coastal processes are to a great extent modified by proximity to man-made structures. Engineered interventions, port facilities, housing and industrial infrastructure, all can increase the coastline fluctuations significantly relative to those along a long unobstructed coastline. As a consequence, coastlines are increasingly exposed to coastal erosion, a phenomenon defined as the encroachment of land by the sea after averaging over a period, which is sufficiently long to eliminate the impacts of weather, storm events and local sediment dynamics. In order to provide cost effective management of coastal erosion it is crucial to estimate both the benefits and costs associated with various management alternatives. The initiatives on Integrated Coastal Zone Manegment in Europe, but also the upcoming Marine Strategy Framwork Directive would benefit greatly from a proliferation of socioeconomic information to assist decision makers who must weigh the impacts of various types of coastal improvement and the cost of beach protection/restoration. In that spirit, the objective of the present research is to report the results of a survey undertaken in two resort beaches on the island of Lesvos (Greece), designed to estimate public preferences for avoiding coastal erosion. A mixed methodological approach is employed by combining an open-ended contingent valuation survey with cultural theory of risk perception. The empirical models to analyze individual choices of erosion control programs and the associated welfare measures are presented, followed by the discussion of model specification and estimation issues, and the results of the data analysis. Some concluding remarks are then presented. By choosing this approach we aim at improving our understanding of preference structure for avoiding public risk, accepted level of risk and perceptions thereof. The framework can also be used for assessing the social cost of extreme weather events such as storm surges in the coastal zone, to get an insight for insurance values.

  9. DNA stable-isotope probing of oil sands tailings pond enrichment cultures reveals different key players for toluene degradation under methanogenic and sulfidogenic conditions.

    Science.gov (United States)

    Laban, Nidal Abu; Dao, Anh; Foght, Julia

    2015-05-01

    Oil sands tailings ponds are anaerobic repositories of fluid wastes produced by extraction of bitumen from oil sands ores. Diverse indigenous microbiota biodegrade hydrocarbons (including toluene) in situ, producing methane, carbon dioxide and/or hydrogen sulfide, depending on electron acceptor availability. Stable-isotope probing of cultures enriched from tailings associated specific taxa and functional genes to (13)C6- and (12)C7-toluene degradation under methanogenic and sulfate-reducing conditions. Total DNA was subjected to isopycnic ultracentrifugation followed by gradient fraction analysis using terminal restriction fragment length polymorphism (T-RFLP) and construction of 16S rRNA, benzylsuccinate synthase (bssA) and dissimilatory sulfite reductase (dsrB) gene clone libraries. T-RFLP analysis plus sequencing and in silico digestion of cloned taxonomic and functional genes revealed that Clostridiales, particularly Desulfosporosinus (136 bp T-RF) contained bssA genes and were key toluene degraders during methanogenesis dominated by Methanosaeta. Deltaproteobacterial Desulfobulbaceae (157 bp T-RF) became dominant under sulfidogenic conditions, likely because the Desulfosporosinus T-RF 136 apparently lacks dsrB and therefore, unlike its close relatives, is presumed incapable of dissimilatory sulfate reduction. We infer incomplete oxidation of toluene by Desulfosporosinus in syntrophic association with Methanosaeta under methanogenic conditions, and complete toluene oxidation by Desulfobulbaceae during sulfate reduction. PMID:25873466

  10. Isolation and characterization of a mesophilic heavy-metals-tolerant sulfate-reducing bacterium Desulfomicrobium sp. from an enrichment culture using phosphogypsum as a sulfate source

    International Nuclear Information System (INIS)

    A sulfate-reducing bacterium, was isolated from a 6 month trained enrichment culture in an anaerobic media containing phosphogypsum as a sulfate source, and, designated strain SA2. Cells of strain SA2 were rod-shaped, did not form spores and stained Gram-negative. Phylogenetic analysis of the 16S rRNA gene sequence of the isolate revealed that it was related to members of the genus Desulfomicrobium (average sequence similarity of 98%) with Desulfomicrobium baculatum being the most closely related (sequence similarity of 99%). Strain SA2 used thiosulfate, sulfate, sulfite and elemental sulfur as electron acceptors and produced sulfide. Strain SA2 reduced sulfate contained in 1-20 g/L phosphogypsum to sulfide with reduction of sulfate contained in 2 g/L phosphogypsum being the optimum concentration. Strain SA2 grew with metalloid, halogenated and non-metal ions present in phosphogypsum and with added high concentrations of heavy metals (125 ppm Zn and 100 ppm Ni, W, Li and Al). The relative order for the inhibitory metal concentrations, based on the IC50 values, was Cu, Te > Cd > Fe, Co, Mn > F, Se > Ni, Al, Li > Zn

  11. CD133-enriched Xeno-Free human embryonic-derived neural stem cells expand rapidly in culture and do not form teratomas in immunodeficient mice

    Directory of Open Access Journals (Sweden)

    Daniel L. Haus

    2014-09-01

    Full Text Available Common methods for the generation of human embryonic-derived neural stem cells (hNSCs result in cells with potentially compromised safety profiles due to maintenance of cells in conditions containing non-human proteins (e.g. in bovine serum or on mouse fibroblast feeders. Additionally, sufficient expansion of resulting hNSCs for scaling out or up in a clinically relevant time frame has proven to be difficult. Here, we report a strategy that produces hNSCs in completely “Xeno-Free” culture conditions. Furthermore, we have enriched the hNSCs for the cell surface marker CD133 via magnetic sorting, which has led to an increase in the expansion rate and neuronal fate specification of the hNSCs in vitro. Critically, we have also confirmed neural lineage specificity upon sorted hNSC transplantation into the immunodeficient NOD-scid mouse brain. The future use or adaptation of these protocols has the potential to better facilitate the advancement of pre-clinical strategies from the bench to the bedside.

  12. Denitrifying bacteria from the terrestrial subsurface exposed to mixed waste contamination

    Energy Technology Data Exchange (ETDEWEB)

    Green, Stefan [Florida State University; Prakash, Om [Florida State University; Gihring, Thomas [Florida State University; Akob, Denise M. [Florida State University; Jasrotia, Puja [Florida State University; Jardine, Philip M [ORNL; Watson, David B [ORNL; Brown, Steven D [ORNL; Palumbo, Anthony Vito [ORNL; Kostka, Joel [Florida State University

    2010-01-01

    In terrestrial subsurface environments where nitrate is a critical groundwater contaminant, few cultivated representatives are available with which to verify the metabolism of organisms that catalyze denitrification. In this study, five species of denitrifying bacteria from three phyla were isolated from subsurface sediments exposed to metal radionuclide and nitrate contamination as part of the U.S. Department of Energy s Oak Ridge Integrated Field Research Challenge (OR-IFRC). Isolates belonged to the genera Afipia and Hyphomicrobium (Alphaproteobacteria), Rhodanobacter (Gammaproteobacteria), Intrasporangium (Actinobacteria) and Bacillus (Firmicutes). Isolates from the phylum Proteobacteria were confirmed as complete denitrifiers, whereas the Gram-positive isolates reduced nitrate to nitrous oxide. Ribosomal RNA gene analyses reveal that bacteria from the genus Rhodanobacter comprise a diverse population of circumneutral to moderately acidophilic denitrifiers at the ORIFRC site, with a high relative abundance in areas of the acidic source zone. Rhodanobacter species do not contain a periplasmic nitrite reductase and have not been previously detected in functional gene surveys of denitrifying bacteria at the OR-IFRC site. Sequences of nitrite and nitrous oxide reductase genes were recovered from the isolates and from the terrestrial subsurface by designing primer sets mined from genomic and metagenomic data and from draft genomes of two of the isolates. We demonstrate that a combination of cultivation, genomic and metagenomic data are essential to the in situ characterization of denitrifiers and that current PCR-based approaches are not suitable for deep coverage of denitrifying microorganisms. Our results indicate that the diversity of denitrifiers is significantly underestimated in the terrestrial subsurface.

  13. Denitrifying bacteria from the terrestrial subsurface exposed to mixed waste contamination

    International Nuclear Information System (INIS)

    In terrestrial subsurface environments where nitrate is a critical groundwater contaminant, few cultivated representatives are available with which to verify the metabolism of organisms that catalyze denitrification. In this study, five species of denitrifying bacteria from three phyla were isolated from subsurface sediments exposed to metal radionuclide and nitrate contamination as part of the U.S. Department of Energy's Oak Ridge Integrated Field Research Challenge (OR-IFRC). Isolates belonged to the genera Afipia and Hyphomicrobium (Alphaproteobacteria), Rhodanobacter (Gammaproteobacteria), Intrasporangium (Actinobacteria) and Bacillus (Firmicutes). Isolates from the phylum Proteobacteria were confirmed as complete denitrifiers, whereas the Gram-positive isolates reduced nitrate to nitrous oxide. Ribosomal RNA gene analyses reveal that bacteria from the genus Rhodanobacter comprise a diverse population of circumneutral to moderately acidophilic denitrifiers at the ORIFRC site, with a high relative abundance in areas of the acidic source zone. Rhodanobacter species do not contain a periplasmic nitrite reductase and have not been previously detected in functional gene surveys of denitrifying bacteria at the OR-IFRC site. Sequences of nitrite and nitrous oxide reductase genes were recovered from the isolates and from the terrestrial subsurface by designing primer sets mined from genomic and metagenomic data and from draft genomes of two of the isolates. We demonstrate that a combination of cultivation, genomic and metagenomic data are essential to the in situ characterization of denitrifiers and that current PCR-based approaches are not suitable for deep coverage of denitrifying microorganisms. Our results indicate that the diversity of denitrifiers is significantly underestimated in the terrestrial subsurface.

  14. Effect of pH on the denitrifying enzyme activity in pasture soils in relation to the intrinsic differences in denitrifier communities.

    Czech Academy of Sciences Publication Activity Database

    ?uhel, Ji?í; Šimek, Miloslav

    2011-01-01

    Ro?. 56, ?. 3 (2011), s. 230-235. ISSN 0015-5632 R&D Projects: GA MŠk LC06066; GA AV ?R IAA600660605 Institutional research plan: CEZ:AV0Z60660521 Keywords : pH * denitrifying enzyme activity * pasture soils Subject RIV: EH - Ecology, Behaviour Impact factor: 0.677, year: 2011

  15. Nutrient removal efficiency in a rice-straw denitrifying bioreactor.

    Science.gov (United States)

    Liang, Xinqiang; Lin, Limin; Ye, Yushi; Gu, Jiatao; Wang, Zhibo; Xu, Lixian; Jin, Yi; Ru, Qiukai; Tian, Guangming

    2015-12-01

    Rice straw was used as a carbon source in a denitrifying bioreactor, for the removal of nutrients from agricultural drainage. Nutrient removal efficiency was evaluated by: (a) nutrient loading rates (low, medium, and high); (b) hydraulic retention time, and (c) comparison with another carbon source (woodchip). The results show that concentrations of nitrate nitrogen (NO3(-)-N), ammonia nitrogen (NH4(+)-N), total nitrogen (TN), and orthophosphate phosphorus (PO4(3-)-P) in the rice-straw bioreactor effluents were reduced by 53%, 25%, 40%, and 35%, respectively, compared with influents at the medium nutrient loading rate (NO3(-)-N: 10-15mgNL(-1), NH4(+)-N: 10-15mgNL(-1), PO4(3-)-P: 1.0-1.5mgPL(-1)) and long hydraulic retention time (HRT, 24h), with a corresponding denitrification rate (DR) of 0.40mgNL(-1)h(-1). Moreover, the rice-straw bioreactor showed significantly higher (p<0.05) nutrient removal efficiency than the woodchip bioreactor at the medium nutrient loading rate and 24h HRT. PMID:26454040

  16. Differential isotopic fractionation during Cr(VI) reduction by an aquifer-derived bacterium under arobic versus denitrifying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Han, R.; Qin, L.; Brown, S. T.; Christensen, J. N.; Beller, H. R.

    2012-02-01

    We studied Cr isotopic fractionation during Cr(VI) reduction by Pseudomonas stutzeri strain RCH2. Despite the fact that strain RCH2 reduces Cr(VI) co-metabolically under both aerobic and denitrifying conditions and at similar specific rates, fractionation was markedly different under these two conditions (ε ~2? aerobically and ~0.4? under denitrifying conditions).

  17. Metaproteogenomic analysis of a sulfate-reducing enrichment culture reveals genomic organization of key enzymes in the m-xylene degradation pathway and metabolic activity of proteobacteria.

    Science.gov (United States)

    Bozinovski, Dragana; Taubert, Martin; Kleinsteuber, Sabine; Richnow, Hans-Hermann; von Bergen, Martin; Vogt, Carsten; Seifert, Jana

    2014-10-01

    This study aimed to ascertain the functional and phylogenetic relationships within an m-xylene degrading sulfate-reducing enrichment culture, which had been maintained for several years in the laboratory with m-xylene as the sole source of carbon and energy. Previous studies indicated that a phylotype affiliated to the Desulfobacteraceae was the main m-xylene assimilating organism. In the present study, genes and gene products were identified by a metaproteogenomic approach using LC-MS/MS analysis of the microbial community, and 2426 peptides were identified from 576 proteins. In the metagenome of the community, gene clusters encoding enzymes involved in fumarate addition to a methyl moiety of m-xylene (nms, bss), as well as gene clusters coding for enzymes involved in modified beta-oxidation to (3-methyl)benzoyl-CoA (bns), were identified in two separate contigs. Additionally, gene clusters containing homologues to bam genes encoding benzoyl-CoA reductase (Bcr) class II, catalyzing the dearomatization of (3-methyl)benzoyl-CoA, were identified. Time-resolved protein stable isotope probing (protein-SIP) experiments using (13)C-labeled m-xylene showed that the respective gene products were highly (13)C-labeled. The present data suggested the identification of gene products that were similar to those involved in methylnaphthalene degradation even though the consortium was not capable of growing in the presence of naphthalene, methylnaphthalene or toluene as substrates. Thus, a novel branch of enzymes was found that was probably specific for anaerobic m-xylene degradation. PMID:25156802

  18. Uranium enrichment

    International Nuclear Information System (INIS)

    Canada is the world's largest producer and exporter of uranium, most of which is enriched elsewhere for use as fuel in LWRs. The feasibility of a Canadian uranium-enrichment enterprise is therefore a perennial question. Recent developments in uranium-enrichment technology, and their likely impacts on separative work supply and demand, suggest an opportunity window for Canadian entry into this international market. The Canadian opportunity results from three particular impacts of the new technologies: 1) the bulk of the world's uranium-enrichment capacity is in gaseous diffusion plants which, because of their large requirements for electricity (more than 2000 kW·h per SWU), are vulnerable to competition from the new processes; 2) the decline in enrichment costs increases the economic incentive for the use of slightly-enriched uranium (SEU) fuel in CANDU reactors, thus creating a potential Canadian market; and 3) the new processes allow economic operation on a much smaller scale, which drastically reduces the investment required for market entry and is comparable with the potential Canadian SEU requirement. The opportunity is not open-ended. By the end of the century the enrichment supply industry will have adapted to the new processes and long-term customer/supplier relationships will have been established. In order to seize the opportunity, Canada must become a credible supplier during this century

  19. Comparison of alcohol shock enrichment and selective enrichment for the isolation of Clostridium difficile.

    OpenAIRE

    Riley, T. V.; Brazier, J. S.; Hassan, H.; Williams, K; Phillips, K D

    1987-01-01

    Two enrichment methods were compared for their ability to recover Clostridium difficile from stool samples. One method used selective enrichment in an antibiotic-containing broth followed by detection with a latex particle agglutination (LPA) reagent. The other used enrichment in a non-selective broth following treatment of the specimen with alcohol. With clinical specimens enrichment culture was significantly more successful at detecting C. difficile than direct plating. Alcohol shock enrich...

  20. Mapping spatial patterns of denitrifiers for bridging community ecology and microbial processes along environmental gradients

    Science.gov (United States)

    Bru, D.; Cuhel, J.; Saby, N.; Cheneby, D.; Chronokova, A.; Arrouays, D.; Martin-Laurent, F.; Simek, M.

    2010-12-01

    While there is ample evidence that microbial processes can exhibit large variations at a field scale, very little is known about the spatial distribution of the communities mediating these processes. To explore spatial patterns of size and activity of the denitrifying community, a functional guild involved in N-cycling, in a grassland field subjected to different cattle grazing regimes.We used geostatistical modeling to map the distribution of size and activity of the denitrifier community in the pasture. Size of the denitrifier community was estimated by PCR quantification of the denitrification gene copy numbers while its activity was estimated by measuring potential denitrification activity and potential N2O emissions. Non-random distribution patterns of the size and of the activity of the denitrifier community were observed with a field-scale spatial dependence. The soil properties, which were strongly affected by presence of cattle, imposed significant control on potential denitrification activity, potential N2O production but not on the size of the denitrifier community. The relative abundance of bacteria possessing the nosZ gene encoding the N2O reductase within the total bacterial community was a strong predictor of the N2O/N2 ratio. Our results clearly indicated that patterns of distribution of the abundance of denitrifiers can be modelled at a field scale. Characterization of such pattern at a field-scale constitutes the first step in modelling distribution of functional bacterial communities at a scale compatible with land management strategies. The absolute abundance of most denitrification genes was not correlated with potential denitrification activity or potential N2O production. However, the relative abundance of bacteria possessing the nosZ gene in the total bacterial community was a strong predictor of the N2O/(N2+N2O) ratio, suggesting a relationship between ecosystem processes and bacterial community composition.

  1. Concurrent Activity of Anammox and Denitrifying Bacteria in the Black Sea

    Directory of Open Access Journals (Sweden)

    JohnB.Kirkpatrick

    2012-07-01

    Full Text Available After the discovery of ANaerobic AMMonium OXidation (anammox in the Black Sea in 2003, the role of heterotrophic denitrification as the main marine pathway for fixed N loss was questioned. A 3 part, 15 month time series investigating Black Sea nitrite reductase (nirS mRNA transcripts at a single location was conducted in order to better understand the activity of anammox and denitrifying bacteria. Here we show that both of these groups were active, as well as being concurrent in the lower suboxic zone over this time span. Their distributions, however, were fundamentally different; denitrification expression was much more variable. Depth profiles covering the suboxic zone showed that the four groups of anammox-type sequences were expressed consistently in the lower suboxic zone, and were consistent with anammox 16S rDNA gene profiles. By contrast, denitrifier-type nirS sequence groups were mixed; half of the groups exhibited consistent expression in the lower suboxic zone, while others varied between season and depth. Co-occurrence of both anammox and denitrifier expression was common and ongoing. Both types of transcripts were also found in samples with low concentrations of sulfide ( >2 ?M. 6 major groups of denitrifier-type nirS transcripts were identified, making these transcripts more diverse than previous DNA clone libraries. Several groups of denitrifier-type nirS transcripts were closely related to sequences from the Baltic Sea. An increase in denitrifier-type nirS transcript diversity and depth range in October 2007 corresponded to an increase in mixed layer net community productivity as measured by O2/Ar gas ratios, as well as to an increase in N2 concentrations in the upper suboxic zone. Taken together, the variations in expression patterns between anammox and denitrification provide one explanation as to how near instantaneous rate measurements, such as isotope spike experiments, may regularly detect anammox activity but underreport denitrification.

  2. Effect of pyrene on denitrification activity and abundance and composition of denitrifying community in an agricultural soil

    International Nuclear Information System (INIS)

    Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene to a series of concentrations (0-500 mg kg-1) followed by dose-response and dynamic incubation experiments. Results showed a positive correlation between potential denitrification activity and copy numbers of denitrifying functional genes (nirK, nirS and nosZ), and were both negatively correlated with pyrene concentrations. Based on the comparison of EC50 values, denitrifiers harboring nirK, nirS or nosZ gene were more sensitive than denitrification activity, and denitrifiers harboring nirS gene were more sensitive than that harboring nirK or nosZ genes. Seven days after spiking with EC50 concentration of pyrene, denitrifiers diversity decreased and community composition changed in comparison with the control. Phylogenetic analyses of three genes showed that the addition of pyrene increased the proportion of Bradyrhizobiaceae, Rhodospirillales, Burkholderiales and Pseudomonadales. Some species belonging to these groups were reported to be able to degrade PAHs. - Highlights: ? Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene. ? PDA was positively correlated with the abundance of denitrifiers harboring nirK, nirS or nosZ gene. ? Both PDA and the abundance of denitrifiers were negatively correlated with pyrene concentrations. ? Denitrifiers harboring nirk, nirS or nosZ gene are more sensitive to pyrene than PDA in soils. - Denitrifiers harboring nirK, nirS or nosZ gene are more sensitive to pyrene contamination than potential denitrification activity in soils.

  3. Effect of pyrene on denitrification activity and abundance and composition of denitrifying community in an agricultural soil

    Energy Technology Data Exchange (ETDEWEB)

    Guo Guangxia; Deng Huan; Qiao Min; Mu Yujing [State Key Lab of Regional and Urban Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhu Yongguan, E-mail: ygzhu@rcees.ac.cn [State Key Lab of Regional and Urban Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China)

    2011-07-15

    Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene to a series of concentrations (0-500 mg kg{sup -1}) followed by dose-response and dynamic incubation experiments. Results showed a positive correlation between potential denitrification activity and copy numbers of denitrifying functional genes (nirK, nirS and nosZ), and were both negatively correlated with pyrene concentrations. Based on the comparison of EC{sub 50} values, denitrifiers harboring nirK, nirS or nosZ gene were more sensitive than denitrification activity, and denitrifiers harboring nirS gene were more sensitive than that harboring nirK or nosZ genes. Seven days after spiking with EC{sub 50} concentration of pyrene, denitrifiers diversity decreased and community composition changed in comparison with the control. Phylogenetic analyses of three genes showed that the addition of pyrene increased the proportion of Bradyrhizobiaceae, Rhodospirillales, Burkholderiales and Pseudomonadales. Some species belonging to these groups were reported to be able to degrade PAHs. - Highlights: > Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene. > PDA was positively correlated with the abundance of denitrifiers harboring nirK, nirS or nosZ gene. > Both PDA and the abundance of denitrifiers were negatively correlated with pyrene concentrations. > Denitrifiers harboring nirk, nirS or nosZ gene are more sensitive to pyrene than PDA in soils. - Denitrifiers harboring nirK, nirS or nosZ gene are more sensitive to pyrene contamination than potential denitrification activity in soils.

  4. Self-protected nitrate reducing culture for intrinsic repair of concrete cracks

    Science.gov (United States)

    Er?an, Yusuf Ç.; Gruyaert, Elke; Louis, Ghislain; Lors, Christine; De Belie, Nele; Boon, Nico

    2015-01-01

    Attentive monitoring and regular repair of concrete cracks are necessary to avoid further durability problems. As an alternative to current maintenance methods, intrinsic repair systems which enable self-healing of cracks have been investigated. Exploiting microbial induced CaCO3 precipitation (MICP) using (protected) axenic cultures is one of the proposed methods. Yet, only a few of the suggested healing agents were economically feasible for in situ application. This study presents a NO3? reducing self-protected enrichment culture as a self-healing additive for concrete. Concrete admixtures Ca(NO3)2 and Ca(HCOO)2 were used as nutrients. The enrichment culture, grown as granules (0.5–2 mm) consisting of 70% biomass and 30% inorganic salts were added into mortar without any additional protection. Upon 28 days curing, mortar specimens were subjected to direct tensile load and multiple cracks (0.1–0.6 mm) were achieved. Cracked specimens were immersed in water for 28 days and effective crack closure up to 0.5 mm crack width was achieved through calcite precipitation. Microbial activity during crack healing was monitored through weekly NOx analysis which revealed that 92 ± 2% of the available NO3? was consumed. Another set of specimens were cracked after 6 months curing, thus the effect of curing time on healing efficiency was investigated, and mineral formation at the inner crack surfaces was observed, resulting in 70% less capillary water absorption compared to healed control specimens. In conclusion, enriched mixed denitrifying cultures structured in self-protecting granules are very promising strategies to enhance microbial self-healing. PMID:26583015

  5. Effect of long-term wastewater irrigation on potential denitrification and denitrifying communities in soils at the watershed scale.

    Science.gov (United States)

    Guo, Guang-Xia; Deng, Huan; Qiao, Min; Yao, Huai-Ying; Zhu, Yong-Guan

    2013-04-01

    Wastewater irrigation mitigates the problem of water shortage but leads to the potential accumulation of pollutants and causes corresponding changes in denitrifying communities and denitrification, hence the potential ecological risk of long-term wastewater irrigation should not be overlooked. We investigated the relative contributions of different environmental factors to the abundance and diversity of denitrifying communities harboring nirK, nirS, and nosZ genes and the relative importance of these biotic and abiotic variables in potential denitrification activity (PDA) in soils with wastewater irrigation for around 25 years at a large watershed scale. Results showed that soil physicochemical properties, pollutants, including heavy metals and PAHs, and vegetation are the major factor groups influencing the abundance and structure of the three denitrifying communities and PDA. NirK-, nirS-, or nosZ-harboring denitrifiers responded in different manners to environmental changes, and were mainly influenced by substrate concentration, carbon source, or pollutants, respectively. The structure of the three denitrifying communities was more relevant to the environmental changes than their abundance. Conversely, the abundance, rather than diversity, was correlated with PDA. Pollutants and vegetation could affect PDA by both direct and indirect paths through soil physicochemical properties including pH, carbon and nitrogen sources, or through the abundance of denitrifying functional genes. The abundance of denitrifying functional genes is a valuable index that integrates potential activity and various environmental factors, and is therefore a good predictor of denitrification in the presence of environmental changes. PMID:23445539

  6. [Effect of denitrifying biofilm development on the surface configuration and chemical composition of PBS polymer].

    Science.gov (United States)

    Zhou, Hai-hong; Wang, Jian-long; Zhao, Xuan

    2006-12-01

    PBS, a new kind of biodegradable polymers (BDPs), can be used as carbon source and biofilm carrier to remove nitrate from drinking water source. The effect of denitrification on the surface configuration and chemical composition of PBS was analyzed by using IR spectrum and SEM observation. The results showed that PBS could be only decomposed under attack of microbial enzymes and provided the carbon source for biomass. Influent nitrate concentration (53 mg x L- 1) can be reduced to less than 10 mg x L(-1) within 12 h. The IR spectrum showed that under development of denitrifying biofilm, absorption band at 2 925 cm(-1),2 850 cm(-1), 3200 cm(-1) -3410 cm-1 became weak, which suggested that the content of methyl or hydroxyl group in PBS decreased slightly, and the other functional groups were not influenced apparently. The main monomer gradients of PBS, such as starch and ethylene, could all be utilized as carbon source by denitrifiers. The SEM observation indicated that the cavity could be formed on the PBS granular surface, which increased the area for denitrifiers to attach. The formation of the cavity structure on the PBS surface was beneficial to further development of compact biofilm, which can protect denitrifiers. PMID:17304849

  7. Mapping field-scale spatial patterns of size and activity of the denitrifier community.

    Czech Academy of Sciences Publication Activity Database

    Philippot, L.; ?uhel, Ji?í; Saby, N.P.A.; Chéneby, D.; Chro?áková, Alica; Bru, D.; Arrouays, D.; Martin-Laurent, F.; Šimek, Miloslav

    2009-01-01

    Ro?. 11, ?. 6 (2009), s. 1518-1526. ISSN 1462-2912 R&D Projects: GA MŠk MEB020726; GA MŠk LC06066; GA AV ?R IAA600660605 Institutional research plan: CEZ:AV0Z60660521 Keywords : field-scale spatial patterns * denitrifier community Subject RIV: EH - Ecology, Behaviour Impact factor: 4.909, year: 2009

  8. Post cold-storage conditioning time affects soil denitrifying enzyme activity

    DEFF Research Database (Denmark)

    Chirinda, Ngoni; Olesen, Jørgen E; Porter, John R.

    2011-01-01

    Soil denitrifying enzyme activity (DEA) is often assessed after cold storage. Previous studies using the short-term acetylene inhibition method have not considered conditioning time (post-cold-storage warm-up time prior to soil analysis) as a factor influencing results. We observed fluctuations in DEA following cold storage, suggesting a need to consider conditioning time when planning and interpreting results.

  9. Post-cold-storage conditioning time affects soil denitrifying enzyme activity

    DEFF Research Database (Denmark)

    Chirinda, Ngonidzashe; Olesen, Jørgen Eivind; Porter, John Roy

    2011-01-01

    Soil denitrifying enzyme activity (DEA) is often assessed after cold storage. Previous studies using the short-term acetylene inhibition method have not considered conditioning time (post-cold-storage warm-up time prior to soil analysis) as a factor influencing results. We observed fluctuations in DEA following cold storage, suggesting a need to consider conditioning time when planning and interpreting results.

  10. Mapping spatial patterns of denitrifiers for bridging community ecology and microbial processes along environmental gradients.

    Czech Academy of Sciences Publication Activity Database

    Philippot, L.; ?uhel, Ji?í; Saby, N.P.A.; Chéneby, D.; Chro?áková, Alica; Bru, D.; Arrouays, D.; Martin-Laurent, F.; Šimek, Miloslav

    Uppsala : Swedish University of Agricultural Sciences, 2009. s. 110. [BAGECO 10. Bacterial Genetics and Ecology - Coexisting on a Changing Planet. 15.06.2009-19.06.2009, Uppsala] Institutional research plan: CEZ:AV0Z60660521 Keywords : spatial patterns * denitrifiers * microbial processes Subject RIV: EH - Ecology, Behaviour

  11. Cattle activities affect abundance and activity of nitrifying and denitrifying microbial communities in upland soil.

    Czech Academy of Sciences Publication Activity Database

    Chro?áková, Alica; Radl, V.; ?uhel, Ji?í; Gattinger, A.; Šimek, Miloslav; Elhottová, Dana; Schloter, M.

    Uppsala : Swedish University of Agriculture Sciences, 2007. [Achievements of COST 856. Denitrification and related aspects. Final meeting of the ESF COST Action 856 /14./. 05.12.2007-08.12.2007, Uppsala] Institutional research plan: CEZ:AV0Z60660521 Keywords : cattle activities * nitrifying and denitrifying microbial communities * upland soil Subject RIV: EH - Ecology, Behaviour

  12. Job Enrichment

    Science.gov (United States)

    Sanders, Rick

    1970-01-01

    Job enrichment means giving people more decision-making power, more responsibility, more grasp of the totality of the job, and a sense of their own importance in the company. This article presents evidence of the successful working of this approach (Donnelly Mirrors), and the lack of success with an opposing approach (General Motors). (NL)

  13. Multiplex Real-Time PCR Assays for Screening of Shiga Toxin 1 and 2 Genes, Including All Known Subtypes, and Escherichia coli O26-, O111-, and O157-Specific Genes in Beef and Sprout Enrichment Cultures.

    Science.gov (United States)

    Harada, Tetsuya; Iguchi, Atsushi; Iyoda, Sunao; Seto, Kazuko; Taguchi, Masumi; Kumeda, Yuko

    2015-10-01

    Shiga toxin family members have recently been classified using a new nomenclature into three Stx1 subtypes (Stx1a, Stx1c, and Stx1d) and seven Stx2 subtypes (Stx2a, Stx2b, Stx2c, Stx2d, Stx2e, Stx2f, and Stx2g). To develop screening methods for Stx genes, including all of these subtype genes, and Escherichia coli O26-, O111-, and O157-specific genes in laboratory investigations of Shiga toxin-producing E. coli (STEC) foodborne cases, we developed multiplex real-time PCR assays and evaluated their specificity and quantitative accuracy using STEC and non-STEC isolates, recombinant plasmids, and food enrichment cultures and by performing STEC spiking experiments with beef and sprout enrichment cultures. In addition, we evaluated the relationship between the recovery rates of the target strains by direct plating and immunomagnetic separation and the cycle threshold (CT) values of the real-time PCR assays for the Stx subtypes and STEC O26, O111, and O157 serogroups. All three stx1- and seven stx2-subtype genes were detected by real-time PCR with high sensitivity and specificity, and the quantitative accuracy of this assay was confirmed using control plasmids and STEC spiking experiments. The results of the STEC spiking experiments suggest that it is not routinely possible to isolate STEC from enrichment cultures with real-time PCR CT values greater than 30 by direct plating on MacConkey agar, although highly selective media and immunomagnetic beads were able to isolate the inoculated strains from the enrichment cultures. These data suggest that CT values obtained from the highly quantitative real-time PCR assays developed in this study provide useful information to develop effective isolation strategies for STEC from food samples. The real-time PCR assays developed here are expected to aid in investigations of infections or outbreaks caused by STEC harboring any of the stx-subtype genes in the new Stx nomenclature, as well as STEC O26, O111, and O157. PMID:26408128

  14. RELATIONSHIP BETWEEN THE CONCENTRATION OF DENITRIFIERS AND PSEUDOMONAS SPP. IN SOILS: IMPLICATIONS FOR BTX BIOREMEDIATION (R823420)

    Science.gov (United States)

    Aquifer microcosms were used to investigate the effect of stimulating denitrification on microbial population shifts and BTX degradation potential. Selective pressurefor facultative denitrifiers was applied to a treatment set by feeding acetate and nitrate, and cycling electr...

  15. Seasonal variations of nitrate reducing and denitrifying bacteria utilizing hexadecane in Mandovi estuary, Goa, West Coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Sousa, T.D.; Ingole, B.; Sousa, S.D.; Bhosle, S.

    > cfu/ml on minimal media containing hexadecane as the sole carbon source. Highest bacterial counts were obtained during the monsoons. 22% of bacteria capable of hexadecane utilization were nitrate reducing and 12% were denitrifying. 29...

  16. Diversity of nitrite reductase genes (nirS) in the denitrifying water column of the coastal Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Jayakumar, D.A.; Francis, C.A.; Naqvi, S.W.A.; Ward, B.B.

    Denitrification often occurs in the water column, underlying zones of intense productivity and decomposition in upwelling regions. In the denitrifying zone off the southwest coast of India, high concentrations of nitrite (greater than 15 mu M...

  17. Simultaneous removal of sulfide, nitrate and acetate under denitrifying sulfide removal condition: Modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xijun; Chen, Chuan; Wang, Aijie; Guo, Wanqian; Zhou, Xu [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Lee, Duu-Jong, E-mail: djlee@ntu.edu.tw [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Ren, Nanqi, E-mail: rnq@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Chang, Jo-Shu [Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2014-01-15

    Graphical abstract: Model evaluation applied to case study 1: (A-G) S{sup 2?}, NO{sub 3}{sup ?}-N, NO{sub 2}{sup ?}-N, and Ac{sup ?}-C profiles under initial sulfide concentrations of 156.2 (A), 539 (B), 964 (C), 1490 (D), 342.7 (E), 718 (F), and 1140.7 (G) mg L{sup ?1}. The solid line represents simulated result and scatter represents experimental result. -- Highlights: • This work developed a mathematical model for DSR process. • Kinetics of sulfur–nitrogen–carbon and interactions between denitrifiers were studied. • Kinetic parameters of the model were estimated via data fitting. • The model described kinetic behaviors of DSR processes over wide parametric range. -- Abstract: Simultaneous removal of sulfide (S{sup 2?}), nitrate (NO{sub 3}{sup ?}) and acetate (Ac{sup ?}) under denitrifying sulfide removal process (DSR) is a novel biological wastewater treatment process. This work developed a mathematical model to describe the kinetic behavior of sulfur–nitrogen–carbon and interactions between autotrophic denitrifiers and heterotrophic denitrifiers. The kinetic parameters of the model were estimated via data fitting considering the effects of initial S{sup 2?} concentration, S{sup 2?}/NO{sub 3}{sup ?}-N ratio and Ac{sup ?}-C/NO{sub 3}{sup ?}-N ratio. Simulation supported that the heterotrophic denitratation step (NO{sub 3}{sup ?} reduction to NO{sub 2}{sup ?}) was inhibited by S{sup 2?} compared with the denitritation step (NO{sub 2}{sup ?} reduction to N{sub 2}). Also, the S{sup 2?} oxidation by autotrophic denitrifiers was shown two times lower in rate with NO{sub 2}{sup ?} as electron acceptor than that with NO{sub 3}{sup ?} as electron acceptor. NO{sub 3}{sup ?} reduction by autotrophic denitrifiers occurs 3–10 times slower when S{sup 0} participates as final electron donor compared to the S{sup 2?}-driven pathway. Model simulation on continuous-flow DSR reactor suggested that the adjustment of hydraulic retention time is an efficient way to make the reactor tolerating high S{sup 2?} loadings. The proposed model properly described the kinetic behaviors of DSR processes over wide parametric ranges and which can offer engineers with basis to optimize bioreactor operation to improve the treatment capacity.

  18. Uranium enrichment

    International Nuclear Information System (INIS)

    This paper reports that in 1990 the Department of Energy began a two-year project to illustrate the technical and economic feasibility of a new uranium enrichment technology-the atomic vapor laser isotope separation (AVLIS) process. GAO believes that completing the AVLIS demonstration project will provide valuable information about the technical viability and cost of building an AVLIS plant and will keep future plant construction options open. However, Congress should be aware that DOE still needs to adequately demonstrate AVLIS with full-scale equipment and develop convincing cost projects. Program activities, such as the plant-licensing process, that must be completed before a plant is built, could take many years. Further, an updated and expanded uranium enrichment analysis will be needed before any decision is made about building an AVLIS plant. GAO, which has long supported legislation that would restructure DOE's uranium enrichment program as a government corporation, encourages DOE's goal of transferring AVLIS to the corporation. This could reduce the government's financial risk and help ensure that the decision to build an AVLIS plant is based on commercial concerns. DOE, however, has no alternative plans should the government corporation not be formed. Further, by curtailing a planned public access program, which would have given private firms an opportunity to learn about the technology during the demonstration project, DOE may limit its ability to transfer AVLIS to the private sector

  19. A denitrifying bacterium from the deep sea at 11,000-m depth.

    Science.gov (United States)

    Tamegai, H; Li, L; Masui, N; Kato, C

    1997-11-01

    The denitrifying bacterium strain MT-1 was isolated from the mud of the Mariana Trench. The optimal temperature and pressure for growth of this bacterium were found to be 30 degrees C and 0.1 MPa, respectively. However, it showed greater tolerance to low temperature (4 degrees C) and high hydrostatic pressure (50 MPa) as compared with denitrifiers obtained from land. From the results, it can be said that this organism is adapted to the environment of the deep sea. Strain MT-1 was shown to belong to the genus Pseudomonas by analysis of its 16S rDNA. The cytochrome contents of the bacterium were similar to those of Ps. stutzeri in spectrophotometric studies. PMID:9680302

  20. Uranium enrichment policies

    International Nuclear Information System (INIS)

    A review of U enrichment policies is presented. Discussions are included on uranium resource assessment, uranium enrichment activities, DOE enrichment plants, tails assay, DOE natural uranium stockpile, DOE enrichment services, and nuclear fuel assurances

  1. Use of starter cultures of lactic acid bacteria and yeasts as inoculum enrichment for the production of gowé, a sour beverage from Benin

    DEFF Research Database (Denmark)

    Vieira-Dalodé, G.; Madodé, Y.E.; Hounhouigan, J.; Jespersen, Lene; Jakobsen, Mogens

    2008-01-01

    Lactobacillus fermentum, Weissella confusa, Kluyveromyces marxianus and Pichia anomala, previously isolated during natural fermentation of traditional gowé, were tested as inoculum enrichment for controlled fermentation of gowé. The final product was subjected to chemical analysis and sensory evaluation. Growth of the lactic acid bacteria (LAB) and yeasts were verified by determination of colony forming units (CFU) and molecular biology techniques. A significant decrease in pH from 6.1 to 3.3, w...

  2. Non-cultured adipose-derived CD45(-) side population cells are enriched for progenitors that give rise to myofibres in vivo

    DEFF Research Database (Denmark)

    Andersen, Ditte C; Schrøder, Henrik D; Jensen, Charlotte H

    2008-01-01

    Side population (SP) cells are highly able to exclude the Hoechst 33342 dye through membrane transporters, a feature associated with cell immaturity and therefore proposed as a marker of stem cells. Herein we demonstrate that the adipose tissue derived stromal vascular fraction (SVF) contains a novel population of non-haematopoietic "side population" (SPCD45(-)) cells. Simultaneous qRT-PCR of 64 genes revealed that the freshly isolated SPCD45(-) was highly enriched for cells expressing genes rel...

  3. Localization of the cytochrome cd1 and copper nitrite reductases in denitrifying bacteria.

    OpenAIRE

    Coyne, M. S.; Arunakumari, A; Pankratz, H S; Tiedje, J M

    1990-01-01

    The locations of cytochrome cd1 nitrite reductases in Pseudomonas aeruginosa and Pseudomonas fluorescens and copper nitrite reductases in Achromobacter cycloclastes and Achromobacter xylosoxidans were identified. Immunogold labeling with colloidal-gold probes showed that the nitrite reductases were synthesized exclusively in anaerobically grown (denitrifying) cells. Little immunogold label occurred in the cytoplasm of these four strains; most was found in the periplasmic space or was associat...

  4. Anaerobic toluene oxidation to benzyl alcohol and benzaldehyde in a denitrifying Pseudomonas strain.

    OpenAIRE

    Altenschmidt, U; Fuchs, G.

    1992-01-01

    The denitrifying Pseudomonas strain K172 was grown with a generation time of 6 h to a cell density of 0.4 g (dry weight) per liter with toluene and nitrate as substrates. We found that anaerobic cell suspensions oxidize [14C]toluene first to [14C]benzyl alcohol and subsequently to [14C]benzaldehyde. This proves that the methyl group of toluene is oxidized without molecular oxygen to a hydroxymethyl group.

  5. Mapping field-scale spatial patterns of size and activity of the denitrifier community.

    Science.gov (United States)

    Philippot, Laurent; Cuhel, Jiri; Saby, Nicolas P A; Chèneby, Dominique; Chronáková, Alicia; Bru, David; Arrouays, Dominique; Martin-Laurent, Fabrice; Simek, Miloslav

    2009-06-01

    There is ample evidence that microbial processes can exhibit large variations in activity on a field scale. However, very little is known about the spatial distribution of the microbial communities mediating these processes. Here we used geostatistical modelling to explore spatial patterns of size and activity of the denitrifying community, a functional guild involved in N-cycling, in a grassland field subjected to different cattle grazing regimes. We observed a non-random distribution pattern of the size of the denitrifier community estimated by quantification of the denitrification genes copy numbers with a macro-scale spatial dependence (6-16 m) and mapped the distribution of this functional guild in the field. The spatial patterns of soil properties, which were strongly affected by presence of cattle, imposed significant control on potential denitrification activity, potential N(2)O production and relative abundance of some denitrification genes but not on the size of the denitrifier community. Absolute abundance of most denitrification genes was not correlated with the distribution patterns of potential denitrification activity or potential N(2)O production. However, the relative abundance of bacteria possessing the nosZ gene encoding the N(2)O reductase in the total bacterial community was a strong predictor of the N(2)O/(N(2) + N(2)O) ratio, which provides evidence for a relationship between bacterial community composition based on the relative abundance of denitrifiers in the total bacterial community and ecosystem processes. More generally, the presented geostatistical approach allows integrated mapping of microbial communities, and hence can facilitate our understanding of relationships between the ecology of microbial communities and microbial processes along environmental gradients. PMID:19260937

  6. Anaerobic activation of toluene and o-xylene by addition to fumarate in denitrifying strain T.

    OpenAIRE

    Beller, H. R.; Spormann, A M

    1997-01-01

    Anaerobic assays conducted with strain T, a denitrifying bacterium capable of mineralizing toluene to carbon dioxide, demonstrated that toluene-grown, permeabilized cells catalyzed the addition of toluene to fumarate to form benzylsuccinate. This reaction was not dependent on the presence of coenzyme A (CoA) or ATP. In the presence of CoA, formation of E-phenylitaconate from benzylsuccinate was also observed. Kinetic studies demonstrated that the specific rate of benzylsuccinate formation fro...

  7. Sediment denitrifier community composition and nirS gene expression investigated with functional gene microarrays

    DEFF Research Database (Denmark)

    Francis, C.A.; Jackson, G.A.; Ward, B.B.; Bülow, Steffen

    2008-01-01

    A functional gene microarray was used to investigate denitrifier community composition and nitrite reductase (nirS) gene expression in sediments along the estuarine gradient in Chesapeake Bay, USA. The nirS oligonucleotide probe set was designed to represent a sequence database containing 539 Chesapeake Bay clones, as well as sequences from many other environments. Greatest nirS diversity was detected at the freshwater station at the head of the bay and least diversity at the higher salinity sta...

  8. Denitrifying microbial consortium in pasture soil is influenced by the intensity of cattle-induced stress.

    Czech Academy of Sciences Publication Activity Database

    ?uhel, Ji?í; Šimek, Miloslav

    Nijmegen : Radboud University Nijmegen, 2006. s. 38. [ COST Action 856, Ecological Aspects of Denitrification, with Emphasis on Agriculture. Management Committee Meeting & Workshop, New developments in the N-cycle reactions in the first decade of the 21st century. 09.03.2006-11.03.2006, Nijmegen] Institutional research plan: CEZ:AV0Z60660521 Keywords : denitrifying microbial consortium * pasture soil * intensity of cattle-induced stress Subject RIV: EH - Ecology, Behaviour

  9. Sediment denitrifier community composition and nirS gene expression investigated with functional gene microarrays

    DEFF Research Database (Denmark)

    Francis, C.A.; Jackson, G.A.

    2008-01-01

    A functional gene microarray was used to investigate denitrifier community composition and nitrite reductase (nirS) gene expression in sediments along the estuarine gradient in Chesapeake Bay, USA. The nirS oligonucleotide probe set was designed to represent a sequence database containing 539 Chesapeake Bay clones, as well as sequences from many other environments. Greatest nirS diversity was detected at the freshwater station at the head of the bay and least diversity at the higher salinity station near the mouth of the Bay. The most common OTUs from the sequence database were detected on the array with high signal strength in most samples. One of the most abundant OTUs, CB2-S-138, was identified as dominant at the mid-bay site by both microarray and quantitative PCR assays, but it comprised a much smaller fraction of the assemblage in the north and south bay samples. cDNA (transcribed from total RNA extracts) targets were hybridized to the same array to compare the profiles of community composition at the DNA (relative abundance) and mRNA (gene expression) levels. Only the three dominant denitrifying groups (in terms of relative strength of DNA hybridization signal) were detected at the mRNA level. These results suggest that the most actively denitrifying groups are responsible for most nirS expression as well Udgivelsesdato: 2008/11

  10. A comparative study of the bacterial community in denitrifying and traditional enhanced biological phosphorus removal processes.

    Science.gov (United States)

    Lv, Xiao-Mei; Shao, Ming-Fei; Li, Chao-Lin; Li, Ji; Gao, Xin-Lei; Sun, Fei-Yun

    2014-09-17

    Denitrifying phosphorus removal is an attractive wastewater treatment process due to its reduced carbon source demand and sludge minimization potential. Two lab-scale sequencing batch reactors (SBRs) were operated in alternating anaerobic-anoxic (A-A) or anaerobic-oxic (A-O) conditions to achieve denitrifying enhanced biological phosphate removal (EBPR) and traditional EBPR. No significant differences were observed in phosphorus removal efficiencies between A-A SBR and A-O SBR, with phosphorus removal rates being 87.9% and 89.0% respectively. The community structures in denitrifying and traditional EBPR processes were evaluated by high-throughput sequencing of the PCR-amplified partial 16S rRNA genes from each sludge. The results obtained showed that the bacterial community was more diverse in A-O sludge than in A-A sludge. Taxonomy and ?-diversity analyses indicated that a significant shift occurred in the dominant microbial community in A-A sludge compared with the seed sludge during the whole acclimation phase, while a slight fluctuation was observed in the abundance of the major taxonomies in A-O sludge. One Dechloromonas-related OTU outside the 4 known Candidatus "Accumulibacter" clades was detected as the main OTU in A-A sludge at the stationary operation, while Candidatus "Accumulibacter" dominated in A-O sludge. PMID:24964811

  11. Start-up of granule-based denitrifying reactors with multiple magnesium supplementation strategies.

    Science.gov (United States)

    Chen, Hui; He, Li-Ling; Liu, An-Na; Guo, Qiong; Zhang, Zheng-Zhe; Jin, Ren-Cun

    2015-05-15

    In the present work, the effect of Mg(2+) supplementation on the start-up of a denitrification process and the granulation of denitrifying sludge was investigated in three upflow anaerobic sludge blanket (UASB) reactors. The reactors R1 and R2 were continuously and intermittently, respectively, supplied with 50 mg L(-1) Mg(2+), whereas R0 was used as the control. The nitrogen loading rate (NLR) and organic loading rate (OLR) gradually increased, and extremely high values were obtained (36.0 kgN m(-3) d(-1) and 216.0 kgCOD m(-3) d(-1), respectively). Granulation occurred in R1 first, but the reactor capacities were comparable. Suffering from starvation, the R0-R2 performances were comparable. At the end of the experiment, the average diameter of the granules in R0, R1, and R2 were 1.67, 1.72 and 1.68 mm, respectively, and the settling velocities of the granules in R1 and R2 were 1.14-fold the speed of R0. The specific denitrifying activity (SDA) of the sludge from the reactors supplied with Mg(2+) was greater than the reactor without Mg(2+). Intermittent Mg(2+) supplementation was identified as the best choice to be utilized to cultivate denitrifying granules, which was consistent with kinetic analysis. PMID:25837295

  12. Isolation of Burkholderia cepacia by enrichment.

    OpenAIRE

    Flanagan, P G; Paull, A

    1998-01-01

    Burkholderia cepacia is a recognised cause of respiratory failure in patients with cystic fibrosis. The value of routine use of selective enrichment broth to increase the yield of B cepacia from cystic fibrosis sputa was investigated. Two hundred sputa from 86 adult and paediatric patients were cultured onto B cepacia selective agar and also in enrichment broth. The enrichment broths were subcultured after incubation onto B cepacia selective agar. Fourteen sputa from eight patients yielded B ...

  13. Use of starter cultures of lactic acid bacteria and yeasts as inoculum enrichment for the production of gowé, a sour beverage from Benin

    DEFF Research Database (Denmark)

    Vieira-Dalodé, G.; Madodé, Y.E.

    2008-01-01

    Lactobacillus fermentum, Weissella confusa, Kluyveromyces marxianus and Pichia anomala, previously isolated during natural fermentation of traditional gowé, were tested as inoculum enrichment for controlled fermentation of gowé. The final product was subjected to chemical analysis and sensory evaluation. Growth of the lactic acid bacteria (LAB) and yeasts were verified by determination of colony forming units (CFU) and molecular biology techniques. A significant decrease in pH from 6.1 to 3.3, with a concomitant increase in titratable acidity (11 to 60 g/kg as lactic acid, dry weight), was observed after 24 h of fermentation when LAB was used either alone or in combination with yeasts. The LAB count increased significantly from 6.1 to 9.4 log CFU/ml, while the yeast count remained constant throughout fermentation. Repetitive-polymerase chain reaction (rep-PCR) assays performed on isolates during the fermentation confirmed the dominance of the added LAB strains. Sensory evaluation revealed that the product fermented for 7 h with L. fermentum alone or in combination with K. marxianus was as acceptable as the traditional product normally obtained after a minimum of 24 h of fermentation. Consequently, gowé can be obtained by controlled fermentation, using L. fermentum as inoculum enrichment, in a small scale industry.  

  14. Distribution of baroduric, psychrotrophic and culturable nitrifying and denitrifying bacteria in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; PradeepRam, A.S.; Nair, S.; Nath, B.N.; Chandramohan, D.

    minutes-76 degrees 05 minutes E, showed that nitrifying bacteria were present in layers of sediment 0-25 cm below sea floor (bsf) with maximum numbers at sub-surface layers. Their average numbers ranged from 4.0 x 10 sup(4) to 2.43 x 10 sup(8) CFU g sup(-1...

  15. Nitrogen Removal Characteristics of a Newly Isolated Indigenous Aerobic Denitrifier from Oligotrophic Drinking Water Reservoir, Zoogloea sp. N299

    Directory of Open Access Journals (Sweden)

    Ting-Lin Huang

    2015-05-01

    Full Text Available Nitrogen is considered to be one of the most widespread pollutants leading to eutrophication of freshwater ecosystems, especially in drinking water reservoirs. In this study, an oligotrophic aerobic denitrifier was isolated from drinking water reservoir sediment. Nitrogen removal performance was explored. The strain was identified by 16S rRNA gene sequence analysis as Zoogloea sp. N299. This species exhibits a periplasmic nitrate reductase gene (napA. Its specific growth rate was 0.22 h?1. Obvious denitrification and perfect nitrogen removal performances occurred when cultured in nitrate and nitrite mediums, at rates of 75.53% ± 1.69% and 58.65% ± 0.61%, respectively. The ammonia removal rate reached 44.12% ± 1.61% in ammonia medium. Zoogloea sp. N299 was inoculated into sterilized and unsterilized reservoir source waters with a dissolved oxygen level of 5–9 mg/L, pH 8–9, and C/N 1.14:1. The total nitrogen removal rate reached 46.41% ± 3.17% (sterilized and 44.88% ± 4.31% (unsterilized. The cell optical density suggested the strain could survive in oligotrophic drinking water reservoir water conditions and perform nitrogen removal. Sodium acetate was the most favorable carbon source for nitrogen removal by strain N299 (p < 0.05. High C/N was beneficial for nitrate reduction (p < 0.05. The nitrate removal efficiencies showed no significant differences among the tested inoculums dosage (p > 0.05. Furthermore, strain N299 could efficiently remove nitrate at neutral and slightly alkaline and low temperature conditions. These results, therefore, demonstrate that Zoogloea sp. N299 has high removal characteristics, and can be used as a nitrogen removal microbial inoculum with simultaneous aerobic nitrification and denitrification in a micro-polluted reservoir water ecosystem.

  16. Marinobacter hydrocarbonoclasticus NY-4, a novel denitrifying, moderately halophilic marine bacterium

    OpenAIRE

    Li, Rongpeng; Zi, Xiaoli; Wang, Xinfeng; Zhang, Xia; Gao, Haofeng; Hu, Nan

    2013-01-01

    The isolation and characterization of a novel halophilic denitrifying marine bacterium is described. The halophilic bacterium, designated as NY-4, was isolated from soil in Yancheng City, China, and identified as Marinobacter hydrocarbonoclasticus by 16S rRNA gene sequence phylogenetic analysis. This organism can grow in NaCl concentrations ranging from 20 to 120 g/L. Optimum growth occurs at 80 g/L NaCl and pH 8.0. The organism can grow on a broad range of carbon sources and demonstrated eff...

  17. Molecular approaches to understand the regulation of N2O emission from denitrifying bacteria - model strains and soil communities (Invited)

    Science.gov (United States)

    Frostegard, A.; Bakken, L. R.

    2010-12-01

    Emissions of N2O from agricultural soils are largely caused by denitrifying bacteria. Field measurements of N2O fluxes show large variations and depend on several environmental factors, and possibly also on the composition of the denitrifying microbial community. The temporal and spatial variation of fluxes are not adequately captured by biogeochemical models, and few options for mitigations have been invented, which underscores the need to understand the mechanisms underlying the emissions of N2O. Analyses of denitrification genes and transcripts extracted from soils are important for describing the system, but may have limited value for prediction of N2O emissions. In contrast, phenotypic analyses are direct measures of the organisms’ responses to changing environmental conditions. Our approach is to combine phenotypic characterizations using high-resolution gas kinetics, with gene transcription analyses to study denitrification regulatory phenotypes (DRP) of bacterial strains or complex microbial communities. The rich data sets obtained provide a basis for refinement of biochemical and physiological research on this key process in the nitrogen cycle. The strength of this combined approach is illustrated by a series of experiments investigating effects of soil pH on denitrification. Soil pH emerges as a master variable determining the microbial community composition as well as its denitrification product ratio (N2O/N2), with higher ratio in acid than in alkaline soil. It is therefore likely that emissions of N2O from agro-ecosystems will increase in large parts of the world where soil pH is decreasing due to intensified management and increased use of chemical fertilizers. Considering its immense implications, surprisingly few attempts have been made to unravel the mechanisms involved in the pH-control of the product stoichiometry of denitrification. We investigated the kinetics of gas transformations (O2, NO, N2O and N2) and transcription of functional genes in intact soil samples from long-term liming experiments. Expression of nirS (encoding nitrite reductase) and nosZ (encoding N2OR) was generally lower at pH6 compared to pH8, but the nosZ/nirS transcript ratios were similar or even higher at pH6. These results were largely corroborated in refined experiments using extracted bacterial communities from the same soils, which allowed us to better control the pH levels experienced by the cells. The findings indicated that the higher N2O/N2 product ratios at pH6 were due to a post-transcriptional effect. Pure culture experiments using Paracoccus denitrificans demonstrated very low N2O/N2 ratios at pH7 while N2O reduction was severely inhibited by suboptimal pH, and that this inhibition occurred during protein synthesis/assembly rather than at the transcription level. The results are important for the understanding of main factors affecting N2O emissions from terrestrial ecosystems.

  18. Characterization of the denitrifying fraction of phosphate accumulating organisms in biological phosphate removal

    DEFF Research Database (Denmark)

    Meinhold, Jens; Filipe, Carlos D.M.

    1999-01-01

    Results of experimental investigations are presented that strongly support the hypothesis that PAO from activated sludge systems consist of two groups: a) denitrifying PAO (DNPAO) capable of using oxygen and nitrate and b) non-denitrifying PAO (non-DNPAO) only able to use oxygen. Batch experiments were performed in which activated sludge obtained from a pilot scale BIODENIPHO(TM) was submitted to a sequence of anaerobic/anoxic/aerobic, anaerobic/aerobic or anaerobic/anoxic conditions while monitoring the course of NOX-N, NH4-N, PO4-P, PHB and PHV. Several methods for the determination of the two fractions of PAO are performed and compared. This study extends on previously reported results (Kerrn-Jespersen and Henze, 1993) in that the pH was controlled to around pH 7 to assure that phosphate precipitation was minimal, and in the measurement of PHB and PHV. With regards to the latter, the paper also examines the influence of the size of the internal PHA pool on the anoxic phosphorus uptake rate. Simulations implementing existing models for the growth of non-DNPAO and DNPAO are used to confirm the experimental results and to gain a better understanding of some of the observations. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.

  19. Evaluation of the microbial diversity of denitrifying bacteria in batch reactor

    Scientific Electronic Library Online (English)

    S. I., Maintinguer; I. K., Sakamoto; M. A. T., Adorno; M. B. A., Varesche.

    2013-09-01

    Full Text Available Microbial communities in an industrial activated sludge plant may contribute to the denitrification process, but the information on the microorganisms present in denitrifying reactors is still scarce. Removal of inorganic nitrogen compounds can be accomplished by the addition of carbon sources to th [...] e biological process of denitrification. Ethanol is an economically viable alternative as a carbon source in tropical countries like Brazil, with large-scale production from sugarcane. This paper reports the successful aplication of activated sludge with nitrate and ethanol in a batch anaerobic reactor. The operation lasted 61.5 h with total consumption of nitrate in 42.5 h, nitrite generation (2.0 mg/L) and ethanol consumption (830.0 mg/L) in 23.5 h. Denitrifying cell counts by the most probable number at the start of the operation were lower than at the end, confirming the ability of the inoculum from activated sludge for the denitrification process. The samples from cell counts were identified as Acidovorax sp., Acinetobacter sp., Comamonas sp. and uncultured bacteria. Therefore, these species may be involved in nitrate reduction and ethanol consumption in the batch reactor.

  20. Efficiency and detrimental side effects of denitrifying bioreactors for nitrate reduction in drainage water.

    Science.gov (United States)

    Weigelhofer, Gabriele; Hein, Thomas

    2015-09-01

    A laboratory column experiment was conducted to test the efficiency of denitrifying bioreactors for the nitrate (NO3-N) removal in drainage waters at different flow rates and after desiccation. In addition, we investigated detrimental side effects in terms of the release of nitrite (NO2-N), ammonium (NH4-N), phosphate (PO4-P), dissolved organic carbon (DOC), methane (CH4), and dinitrogen oxide (N2O). The NO3-N removal efficiency decreased with increasing NO3-N concentrations, increasing flow rates, and after desiccation. Bioreactors with purely organic fillings showed higher NO3-N removal rates (42.6-55.7 g NO3-N m(-3) day(-1)) than those with organic and inorganic fillings (6.5-21.4 g NO3-N m(-3) day(-1)). The release of NO2-N and DOC was considerable and resulted in concentrations of up to 800 ?g NO2-N L(-1)and 25 mg DOC L(-1) in the effluent water. N2O concentrations increased by 4.0 to 15.3 ?g N2O-N L(-1) between the influent and the effluent, while CH4 production rates were low. Our study confirms the high potential of denitrifying bioreactors to mitigate NO3-N pollution in drainage waters, but highlights also the potential risks for the environment. PMID:25943519

  1. Effect of CO2 enrichment and high photosynthetic photon flux densities (PPFD) on rubisco and PEP-case activities of in vitro cultured strawberry plants

    International Nuclear Information System (INIS)

    Standard growing conditions in vitro (low light and CO2) are not conducive to autotrophy. An experiment was conducted to improve photosynthesis in vitro in the hope of increasing survival in acclimatization. A factorial experiment was elaborated where CO2 and PPFD were supplied to in vitro cultured strawberry plants in the rooting stage. Activities of carboxylating enzymes were determined after 4 weeks of culture. The activities of non-activated and activated rubisco and PEP-Case were measured after extraction of the enzymes and a reaction with NaH14CO3 followed by scintillation counting spectroscopy. High CO2 concentration significantly increased net assimilation rates (NAR) by 165% over the control for both 1650 and 3000 ppm CO2. High PPFD only increased NAR by 12 and 35% for 150 and 250 ?mol·m-2·s-1 respectively over the control. Plants grown at 3000 ppm CO2 had the highest level of chlorophyll/g FW with 97% more than the control. The activity of PEP-Case was the highest at high light levels and high CO2 with rates of 1.65 for 1650 ppm versus 1.22 mmol CO2 mg-1 chl. h-1 at 250 ?mol·m-2·s-1. There was no difference in PEP activity at low light levels. The rubisco activity was lower at 1650 and 3000 ppm CO2. Increases in NAR correlate more closely to the PEP-Case than to Rubisco activity. Physiological significance of high activity of PEP-Case over rubisco will be discussed

  2. Cultivation and irradiation of human fibroblasts in a medium enriched with platelet lysate for obtaining feeder layer in epidermal cell culture; Cultivo e irradiacao de fibroblastos humanos em meio enriquecido com lisado de plaquetas para obtencao de camada de sustentacao em culturas de celulas da epiderme

    Energy Technology Data Exchange (ETDEWEB)

    Yoshito, Daniele

    2011-07-01

    For over 30 years, the use of culture medium, enriched with bovine serum, and murines fibroblasts, with the rate of proliferation controlled by irradiation or by share anticarcinogenic drugs, has been playing successfully its role in assisting in the development of keratinocytes in culture, for clinical purposes. However, currently there is a growing concern about the possibility of transmitting prions and animals viruses to transplanted patients. Taking into account this concern, the present work aims to cultivate human fibroblasts in a medium enriched with human platelets lysate and determine the irradiation dose of these cells, for obtaining feeder layer in epidermal cell culture. For carrying out the proposed objective, platelets lysis has standardized, this lysate was used for human fibroblasts cultivation and the irradiation dose enough to inhibit its duplication was evaluated. Human keratinocytes were cultivated in these feeder layers, in culture medium enriched with the lysate. With these results we conclude that the 10% platelets lysate promoted a better adhesion and proliferation of human fibroblasts and in all dose levels tested (60 to 300 Gy), these had their mitotic activity inactivated by ionizing irradiation, being that the feeder layers obtained with doses from 70 to 150 Gy were those that provided the best development of keratinocytes in medium containing 2.5% of human platelet lysate. Therefore, it was possible to standardize both the cultivation of human fibroblasts as its inactivation for use as feeder layer in culture of keratinocytes, so as to eliminate xenobiotics components. (author)

  3. Acidophilic denitrifiers dominate the N2O production in a 100-year-old tea orchard soil.

    Science.gov (United States)

    Huang, Ying; Long, Xi-En; Chapman, Stephen J; Yao, Huaiying

    2015-03-01

    Aerobic denitrification is the main process for high N2O production in acid tea field soil. However, the biological mechanisms for the high emission are not fully understood. In this study, we examined N2O emission and denitrifier communities in 100-year-old tea soils with four pH levels (3.71, 5.11, 6.19, and 7.41) and four nitrate concentration (0, 50, 200, and 1000 mg kg(-1) of NO3 (-)-N) addition. Results showed the highest N2O emission (10.1 mg kg(-1) over 21 days) from the soil at pH 3.71 with 1000 mg kg(-1) NO3 (-) addition. The N2O reduction and denitrification enzyme activity in the acid soils (pH production and reduction. CCA analysis also showed a negative correlation between the dominant denitrifier ecotypes (nirS TRF 78, nosZ TRF 187) and soil pH. The representative sequences were identical to those of cultivated denitrifiers from acidic soils via phylogenetic tree analysis. Our results showed that the acidophilic denitrifier adaptation to the acid environment results in high N2O emission in this highly acidic tea soil. PMID:25273518

  4. Genome Sequence of the Deep-Sea Denitrifier Pseudomonas sp. Strain MT-1, Isolated from the Mariana Trench.

    Science.gov (United States)

    Fujinami, Shun; Oikawa, Yuji; Araki, Takuma; Shinmura, Yui; Midorikawa, Ryota; Ishizaka, Hikari; Kato, Chiaki; Horikoshi, Koki; Ito, Masahiro; Tamegai, Hideyuki

    2014-01-01

    Pseudomonas sp. strain MT-1 was the first deep-sea denitrifier isolated and characterized from mud recovered from a depth of 11,000 m in the Mariana Trench. We report here the genome sequence of this bacterium, which contributes to our understanding of denitrification and bioenergetics in the deep sea. PMID:25523772

  5. Genome Sequence of the Deep-Sea Denitrifier Pseudomonas sp. Strain MT-1, Isolated from the Mariana Trench

    OpenAIRE

    Fujinami, Shun; Oikawa, Yuji; Araki, Takuma; Shinmura, Yui; Midorikawa, Ryota; Ishizaka, Hikari; Kato, Chiaki; Horikoshi, Koki; ITO, Masahiro; Tamegai, Hideyuki

    2014-01-01

    Pseudomonas sp. strain MT-1 was the first deep-sea denitrifier isolated and characterized from mud recovered from a depth of 11,000 m in the Mariana Trench. We report here the genome sequence of this bacterium, which contributes to our understanding of denitrification and bioenergetics in the deep sea.

  6. Nitrous oxide reductase genes (nosZ) of denitrifying populations in soil and the earthworm gut are phylogenetically similar

    DEFF Research Database (Denmark)

    Horn, Marcus A.; Drake, Harold L.; Schramm, Andreas

    2006-01-01

    Earthworms emit nitrous oxide (N2O) and dinitrogen (N2). It has been hypothesized that the in situ conditions of the earthworm gut activates ingested soil denitrifiers during gut passage and leads to these in vivo emissions (M. A. Horn, A. Schramm, and H. L. Drake, Appl. Environ. Microbiol. 69:1662-1669, 2003). This hypothesis implies that the denitrifiers in the earthworm gut are not endemic to the gut but rather are regular members of the soil denitrifier population. To test this hypothesis, t...

  7. Beyond Job Enrichment to Employment Enrichment

    Science.gov (United States)

    Werther, William B., Jr.

    1975-01-01

    Employment enrichment views the total work environment confronting employees as a system consisting of two overlapping areas: worker-job and worker-organization subsystems. Job enrichment has improved the worker-job subsystem. The focus of this article is on methods of improving the worker-organization relationship. (Author/JB)

  8. Gravimetric enrichment of high lipid and starch accumulating microalgae.

    Science.gov (United States)

    Hassanpour, Morteza; Abbasabadi, Mahsa; Ebrahimi, Sirous; Hosseini, Maryam; Sheikhbaglou, Ahmad

    2015-11-01

    This study presents gravimetric enrichment of mixed culture to screen starch and lipid producing species separately in a sequencing batch reactor. In the enriched starch-producing mixed culture photobioreactor, the starch content at the end of steady state batch became 3.42 times the beginning of depletion. Whereas in the enriched lipid-producing photobioreactor, the lipid content at the end of steady state batch became 3 times the beginning of famine phase. The obtained results revealed that the gravimetric enrichment is a suitable screening method for specific production of storage compounds in none-sterile large-scaled condition. PMID:26218537

  9. Continuous nitrous oxide abatement in a novel denitrifying off-gas bioscrubber.

    Science.gov (United States)

    Frutos, Osvaldo D; Arvelo, Ilan A; Pérez, Rebeca; Quijano, Guillermo; Muñoz, Raúl

    2015-04-01

    The potential of a bioscrubber composed of a packed bed absorption column coupled to a stirred tank denitrification bioreactor (STR) was assessed for 95 days for the continuous abatement of a diluted air emission of N2O at different liquid recycling velocities. N2O removal efficiencies of up to 40?±?1 % were achieved at the highest recirculation velocity (8 m h(-1)) at an empty bed residence time of 3 min using a synthetic air emission containing N2O at 104?±?12 ppmv. N2O was absorbed in the packed bed column and further reduced in the STR at efficiencies >80 % using methanol as electron donor. The long-term operation of the bioscrubber suggested that the specialized N2O degrading community established was not able to use N2O as nitrogen source. Additional nitrification assays showed that the activated sludge used as inoculum was not capable of aerobically oxidizing N2O to nitrate or nitrite, regardless of the inorganic carbon concentration tested. Denitrification assays confirmed the ability of non-acclimated activated sludge to readily denitrify N2O at a specific rate of 3.9 mg N2O g VSS h(-1) using methanol as electron donor. This study constitutes, to the best of our knowledge, the first systematic assessment of the continuous abatement of N2O in air emission. A characterization of the structure of the microbial population in the absorption column by DGGE-sequencing revealed a high microbial diversity and the presence of heterotrophic denitrifying methylotrophs. PMID:25547842

  10. Coexistence of nitrifying, anammox and denitrifying bacteria in a sequencing batch reactor

    Directory of Open Access Journals (Sweden)

    MichelaLangone

    2014-02-01

    Full Text Available Elevated nitrogen removal efficiencies from ammonium-rich wastewaters have been demonstrated by several applications, that combine nitritation and anammox processes. Denitrification will occur simultaneously when organic carbon is also present. In this study, the activity of aerobic ammonia oxidizing, anammox and denitrifying bacteria in a full scale Sequencing Batch Reactor, treating digester supernatants, was studied by means of batch-assays. AOB and anammox activities were maximum at pH of 8.0 and 7.8-8.0, rispectively. Short term effect of nitrite on anammox activity was studied, showing nitrite up to 42 mg/L did not result in inhibition. Both denitrification via nitrate and nitrite were measured. To reduce nitrite-oxidizing activity, high of NH3 – N (1.9-10 mg N-NH3/L and low nitrite (3-8 mg TNN/L are required conditions during the whole SBR cycle.Molecular analysis showed the nitritation-anammox sludge harbored a high microbial diversity, where each microorganism has a specific role. Using ammonia monooxygenase ? –subunit (amoA gene as a marker, our analyses suggested different macro- and micro-environments in the reactor strongly affect the AOB community, allowing the development of different AOB species, such as N. europaea/eutropha and N. oligotropha groups, which improve the stability of nitritation process. A specific PCR primer set, used to target the 16S rRNA gene of anammox bacteria, confirmed the presence of the “Ca. Brocadia fulgida” type, able to grow in precence of organic matter and to tolerate high nitrite concentrations. The diversity of denitrifiers was assessed by using dissimilatory nitrite reductase (nirS gene-based analyses, who showed denitifiers were related to different betaproteobacterial genera, such as Thauera, Pseudomonas, Dechloromonas and Aromatoleum, able to assist in forming microbial aggregates. Concerning possible secondary processes, no n-damo bacteria were found while NOB from the genus of Nitrobacter was detected.

  11. The Role of plant type and salinity in the selection for the denitrifying community structure in the rhizosphere of wetland vegetation

    OpenAIRE

    Bañeras Vives, Lluís; Ruiz Rueda, Olaya; López i Flores, Rocío; Quintana Pou, Xavier; Hallin, Sara

    2012-01-01

    Coastal wetlands, as transient links from terrestrial to marine environments, are important for nitrogen removal by denitrification. Denitrification strongly depends on both the presence of emergent plants and the denitrifier communities selected by different plant species. In this study, the effects of vegetation and habitat heterogeneity on the community of denitrifying bacteria were investigated in nine coastal wetlands in two preserved areas of Spain. Sampling locations were selected to c...

  12. Uranium Enrichment, an overview

    International Nuclear Information System (INIS)

    This general presentation on uranium enrichment will be followed by lectures on more specific topics including descriptions of enrichment processes and assessments of the prevailing commercial and industrial situations. I shall therefore avoid as much as possible duplications with these other lectures, and rather dwell on: some theoretical aspects of enrichment in general, underlying the differences between statistical and selective processes, a review and comparison between enrichment processes, remarks of general order regarding applications, the proliferation potential of enrichment. It is noteworthy that enrichment: may occur twice in the LWR fuel cycle: first by enriching natural uranium, second by reenriching uranium recovered from reprocessing, must meet LWR requirements, and in particular higher assays required by high burn up fuel elements, bears on the structure of the entire front part of the fuel cycle, namely in the conversion/reconversion steps only involving UF6 for the moment. (author). tabs., figs., 4 refs

  13. Enrichment of high ammonia tolerant methanogenic culture

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Proietti, Nicolas; Angelidaki, Irini

    2013-01-01

    Ammonia is the major toxicant in full scale anaerobic digesters of animal wastes which are rich in proteins and/or urea, such as pig or poultry wastes. Ammonia inhibition decreases methane production rates, increases volatile fatty acids concentration and leads to economic losses for the biogas plants. The methods used today to counteract ammonia inhibition are slow and costexpensive. A new biological approach to avoid or counteract ammonia inhibition by using ammonia tolerant methanogens, could...

  14. Population analysis in a denitrifying sand filter: conventional and in situ identification of Paracoccus spp. in methanol-fed biofilms.

    OpenAIRE

    Neef, A.; Zaglauer, A; Meier, H; Amann, R; Lemmer, H; Schleifer, K H

    1996-01-01

    The microbial community of a denitrifying sand filter in a municipal wastewater treatment plant was examined by conventional and molecular techniques to identify the bacteria actively involved in the removal of nitrate. In this system, denitrification is carried out as the last step of water treatment by biofilms growing on quartz grains with methanol as a supplemented carbon source. The biofilms are quite irregular, having a median thickness of 13 to 20 microns. Fatty acid analysis of 56 den...

  15. Influence of Volatile Fatty Acids on Nitrite Accumulation by a Pseudomonas stutzeri Strain Isolated from a Denitrifying Fluidized Bed Reactor

    OpenAIRE

    van Rijn, J; Tal, Y.; Barak, Y.

    1996-01-01

    Intermediate nitrite accumulation during denitrification by Pseudomonas stutzeri isolated from a denitrifying fluidized bed reactor was examined in the presence of different volatile fatty acids. Nitrite accumulated when acetate or propionate served as the carbon and electron source but did not accumulate in the presence of butyrate, valerate, or caproate. Nitrite accumulation in the presence of acetate was caused by differences in the rates of nitrate and nitrite reduction and, in addition, ...

  16. Aerobic and anoxic growth and nitrate removal capacity of a marine denitrifying bacterium isolated from a recirculation aquaculture system

    OpenAIRE

    Borges, Maria-Teresa; Sousa, André; de Marco, Paolo; De Matos, Ana,; Hönigova, Petra; Castro, Paula M. L

    2008-01-01

    Bacterial biofilters used in marine recirculation aquaculture systems need improvements to enhance nitrogen removal efficiency. Relatively little is known about biofilter autochthonous population structure and function. The present study was aimed at isolating and characterizing an Autochthonous denitrifying bacterium from a marine biofilter installed at a recirculation aquaculture system. Colonization of four different media in a marine fish farm was followed by isolation of various denit...

  17. Structure and function of microbial communities in constructed wetlands - influence of environmental parameters and pesticides on denitrifying bacteria

    OpenAIRE

    Milenkovski, Susann

    2009-01-01

    This thesis addresses the interactions and relationships between natural aquatic bacterial communities, environmental parameters, anthropogenic chemicals and the denitrification pathway in the habitat of agricultural constructed wetlands. The main aim was to gain fundamental knowledge of the drivers behind the processes of the denitrification (i.e. nitrogen removal) in constructed wetlands, hence, the structure and function of the denitrifying bacterial community as efficient nitrogen removal...

  18. Effect of Earthworm Feeding Guilds on Ingested Dissimilatory Nitrate Reducers and Denitrifiers in the Alimentary Canal of the Earthworm ? †

    OpenAIRE

    Depkat-Jakob, Peter S.; Hilgarth, Maik; Horn, Marcus A; Drake, Harold L

    2010-01-01

    The earthworm gut is an anoxic nitrous oxide (N2O)-emitting microzone in aerated soils. In situ conditions of the gut might stimulate ingested nitrate-reducing soil bacteria linked to this emission. The objective of this study was to determine if dissimilatory nitrate reducers and denitrifiers in the alimentary canal were affected by feeding guilds (epigeic [Lumbricus rubellus], anecic [Lumbricus terrestris], and endogeic [Aporrectodea caliginosa]). Genes and gene transcripts of narG (encodes...

  19. Impact of plant harvest management on function and community structure of nitrifiers and denitrifiers in a constructed wetland.

    Science.gov (United States)

    Tanaka, Takashi S T; Irbis, Chagan; Wang, Pengyun; Inamura, Tatsuya

    2015-02-01

    Plant harvest is one of the most important management practices in constructed wetlands. In this study, we evaluated the impact of harvesting Phragmites australis (Cav.) Trin. ex Steudel on the activity and community structure of nitrifiers and denitrifiers in a free-water surface constructed wetland. The nitrifiers were targeted using bacterial and archaeal-amoA that encode ammonia monooxygenase, and the denitrifiers were targeted using nirK and nirS that encode the nitrite reductase. The community structures were evaluated using denaturing gradient gel electrophoresis. The potential nitrification and nitrate reduction rates were shown to be significantly higher in the harvested plant rhizosphere than in a non-harvested control plot. The potential nitrification rate positively correlated with the potential nitrate reduction rate and influenced the community structure of nirK. In addition, plant canopy developed differently after harvest and simultaneously changed the microclimate beneath the plant community. These results suggest that plant harvest management could change subsequent plant development and associated microenvironments, thereby affecting the function and community structure of nitrifiers and denitrifiers. Our study highlights the importance of plant harvest management within constructed wetlands to regulate the functions of nitrification and denitrification. PMID:25764547

  20. Phylogenetic analyses and nitrate-reducing activity of fungal cultures isolated from the permanent, oceanic oxygen minimum zone of the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Manohar, C.S.; Menezes, L.D.; Ramasamy, K.P.; Meena, R.M.

    Reports on the active role of fungi as denitrifiers in terrestrial ecosystems have stimulated an interest in the study of the role of fungi in oxygen-deficient marine systems. In this study, the culturable diversity of fungi was investigated from 4...

  1. Advanced enrichment techniques

    International Nuclear Information System (INIS)

    BNFL is in a unique position in that it has commercial experience of diffusion enrichment, and of centrifuge enrichment through its associate company Urenco. In addition BNFL is developing laser enrichment techniques as part of a UK development programme in this area. The paper describes the development programme which led to the introduction of competitive centrifuge enrichment technology by Urenco and discusses the areas where improvements have and will continue to be made in the centrifuge process. It also describes the laser development programme currently being undertaken in the UK. The paper concludes by discussing the relative merits of the various methods of uranium enrichment, with particular reference to the enrichment market likely to obtain over the rest of the century. (author)

  2. The enrichment secondary market

    International Nuclear Information System (INIS)

    This paper will addresses two topics: the background to the present status of the enrichment secondary market and the future outlook of the secondary market in enrichment services, and the viability of the nuclear fuel brokerage industry. These two topics are inevitably connected, as most secondary market activity, not only in enrichment but also in natural uranium, has traditionally been conducted with the participation of brokers. Therefore, the author interrelates these topics

  3. Quantity-activity relationship of denitrifying bacteria and environmental scaling in streams of a forested watershed

    Science.gov (United States)

    O'Connor, Ben L.; Hondzo, Miki; Dobraca, Dina; Lapara, Timothy M.; Finlay, Jacques C.; Brezonik, Patrick L.

    2006-12-01

    The spatial variability of subreach denitrification rates in streams was evaluated with respect to controlling environmental conditions, molecular examination of denitrifying bacteria, and dimensional analysis. Denitrification activities ranged from 0 and 800 ng-N gsed-1 d-1 with large variations observed within short distances (gene that encodes for nitrite reductase. Results showed a range of nirK quantities from 103 to 107 gene-copy-number gsed-1. A nonparametric statistical test showed no significant difference in nirK quantities among stream reaches, but revealed that samples with a high denitrification potential had significantly higher nirK quantities. Denitrification activity was positively correlated with nirK quantities with scatter in the data that can be attributed to varying environmental conditions along stream reaches. Dimensional analysis was used to evaluate denitrification activities according to environmental variables that describe fluid-flow properties, nitrate and organic material quantities, and dissolved oxygen flux. Buckingham's pi theorem was used to generate dimensionless groupings and field data were used to determine scaling parameters. The resulting expressions between dimensionless NO3- flux and dimensionless groupings of environmental variables showed consistent scaling, which indicates that the subreach variability in denitrification rates can be predicted by the controlling physical, chemical, and microbiological conditions.

  4. Evaluation of different culture media and enrichment in orange juice upon the growth of Alicyclobacillus spp. / Avaliação de diferentes meios de cultura e enriquecimento em suco de laranja sobre o crescimento de Alicyclobacillus spp.

    Scientific Electronic Library Online (English)

    Márcia Maria, Anjos; Suelen Pereira, Ruiz; Benício Alves, Abreu Filho.

    2014-04-01

    Full Text Available As bactérias do gênero Alicyiclobacillus spp. formam esporos e se desenvolvem em meios ácidos, podendo causar deterioração em sucos cítricos. O Brasil é o maior exportador de suco de laranja concentrado do mundo e, assim, este gênero vem sendo estudado por causar alterações de odor e sabor. Vários e [...] studos relatam diferentes meios de culturas empregados para a detecção e enumeração de Alicyclobacillus spp. Este estudo teve como objetivo avaliar a recuperação de esporos de Alicyclobacillus spp. nos meios ALI, BAT, K ágar e YSG, utilizando a metodologia indicada pela ABECitrus. Cinco inóculos diferentes foram utilizados, sendo dois de linhagens-referência e os outros três isolados de suco concentrado de laranja pasteurizado. Também foi verificada a recuperação das células após o enriquecimento em suco de laranja reconstituído. Foi inoculada uma população inicial de 6 log UFC/mL. Os meios ALI, BAT e YSG conseguiram recuperar esta população nos diferentes inóculos, não existindo diferenças significativas entre os resultados. Contudo, devido à facilidade do preparo, os meios ALI e YSG mostraram-se mais vantajosos quando comparados ao meio BAT. O meio K ágar apresentou recuperação inferior aos outros meios para todos os inóculos, porém, houve diferença significativa apenas para Alicyclobacillus acidocaldarius 0298 T (3,66 log UFC/mL) e Alicyclobacillus pomorum-like CBMAI 0278 (4,11 log UFC/mL). Abstract in english Bacteria of the genus Alicyiclobacillus spp. form spores and develop in acid media, leading to the spoilage of citrus juices. Brazil is the largest exporter of orange juice concentrate, and yet, it has been extensively studied due to changes in taste and smell. Several investigations have reported d [...] ifferent culture media used to detect and enumerate Alicyiclobacillus spp. The objective of the present study was to evaluate the recovery of Alicyiclobacillus spp. spores grown in ALI, BAT, K agar and YSG media using the methodology suggested by ABECitrus. Five inocula were used, two from reference strains and three from pasteurized concentrated orange juice. Cell recovery after the enrichment in reconstituted orange juice was also analyzed. An initial population of 6 log CFU/mL was inoculated. ALI, BAT and YSG media were able to recover the initial population of all different inocula, with no significant differences between the results. When compared to BAT, however, the preparation of ALI and YSG media was simpler and had more advantages. The recovery with K agar medium was lower than the other media for all the tested inocula, with significant differences found for Alicyclobacillus acidocaldarius 0298T (3.66 log CFU/mL) and Alicyclobacillus pomorum-like CBMAI 0278 (4.11 log CFU/mL).

  5. Commercial developments in enrichment

    International Nuclear Information System (INIS)

    The significance of the dollars spent by government and industry so far on enrichment programs is enhanced by the number of engineering and component design and supply firms who have become involved in the public and private development and design projects. The knowhow gained from this experience provides the nucleus of the industrial manufacturing base for the unique enrichment technology necessary to build the future U.S. enrichment plants. The $1.5 billion CIP/CUP programs now under way and the $4.4 billion Portsmouth Add-On Plant are bringing the U.S. enrichment capacity to the capability to supply the contracted 323 GW of reactors, while conserving uranium by allowing operation at a lower, more nearly optimum tails assay. The government enrichment contract books have remained closed to new orders since July of 1975. Inevitably, new foreign enrichment projects are actively pursuing customers. Until the government or private U.S. enrichment ventures resume contracting activity, the foreign plants have no U.S. competition. The technology exists within ERDA and industry to maintain U.S. leadership in the world enrichment market if the institutional questions can be answered

  6. Developments in uranium enrichment

    International Nuclear Information System (INIS)

    The enrichment services market is still characterized by overcapacities. While consumption worldwide will rise by some 15% to 39,000 t SWU/a over the next ten years, capacities amount to nearly 50,000 t SWU/a. The price for enrichment services probably has reached its all time low. Prices below U.S. $ 100/kg SWU are not likely to cover costs even of the economically most advanced enrichment processes. Urenco has prepared for the difficult enrichment business in the years to come by streamlining and cost cutting measures. The company intends to hold and increase its share of more than 10% in the world market. The uranium enrichment plant of Gronau will be expanded further. Expansion beyond 1000 t is subject to another permit being granted under the Atomic Energy Act, an application for which was filed in December 1994. Centrifuge technology is the superior enrichment technology, i.e., there is still considerable potential for further development. Construction of enrichment plants employing the centrifuge technology in the United States and in France is being pursued in various phases, from feasibility studies to licensing procedures. Before these plants could be implemented, however, considerable problems of organization would have to be solved, and the market would have to change greatly, respectively. The laser process, at the present time, does not seem to be able to develop into a major industrial competitor. (orig.)

  7. Identification of the functional periplasmic nitrate reductase (nap) gene cluster from the deep-sea denitrifier Pseudomonas sp. strain MT-1.

    Science.gov (United States)

    Tamegai, Hideyuki; Ikeda, Eriko; Kato, Chiaki; Horikoshi, Koki

    2007-08-01

    The nap gene cluster encoding periplasmic nitrate reductase was identified from Pseudomonas sp. strain MT-1, a deep-sea denitrifier isolated from the Mariana Trench. The ORFs identified were highly homologous with those of Pseudomonas stutzeri, but the cluster included only four ORFs (napDABC), less than those in other organisms. For other bacteria, some additional small ORFs (such as napE, napF, napG, napH, and napK) are found in the nap gene cluster, although their physiological function is still unclear. The soluble fraction of MT-1 grown under denitrifying condition showed significant nitrate reductase activity. This observation suggests that the periplasmic nitrate reductase encoded by the gene cluster identified in this study is functional. The activity was highest when the organism was grown under denitrifying conditions, suggesting that the enzyme participates in dissimilatory nitrite reduction. PMID:17690469

  8. TRIGA low enrichment fuel

    International Nuclear Information System (INIS)

    Sixty TRIGA reactors have been sold and the earliest of these are now passing twenty years of operation. All of these reactors use the uranium-zirconium hydride fuel (UZrH) which provides certain unique advantages arising out of its large prompt negative temperature coefficient, very low fission product release, and high temperature capability. Eleven of these Sixty reactors are conversions from plate fuel to TRIGA fuel which were made as a result of these advantages. With only a few exceptions, TRIGA reactors have always used low-enriched-uranium (LEU) fuel with an enrichment of 19.9%. The exceptions have either been converted from the standard low-enriched fuel to the 70% enriched FLIP fuel in order to achieve extended lifetime, or are higher powered reactors which were designed for long life using 93%-enriched uranium during the time when the use and export of highly enriched uranium (HEU) was not restricted. The advent of international policies focusing attention on nonproliferation and safeguards made the HEU fuels obsolete. General Atomic immediately undertook a development effort (nearly two years ago) in order to be in a position to comply with these policies for all future export sales and also to provide a low-enriched alternative to fully enriched plate-type fuels. This important work was subsequently partially supported by the U.S. Department of Energy. The laboratory and production tests have shown that higher uranium densities can be achieved to compensate for reducing the enrichment to 20%, and that the fuels maintain the characteristics of the very thoroughly proven standard TRIGA fuels. In May of 1978, General Atomic announced that these fuels were available for TRIGA reactors and for plate-type reactors with power levels up to 15 MW with GA's standard commercial warranty

  9. TRIGA low enrichment fuel

    International Nuclear Information System (INIS)

    Sixty TRIGA reactors have been sold and the earliest of these are now passing twenty years of operation. All of these reactors use the uranium zirconium hydride fuel (UZrH) which provides certain unique advantages arising out of its large prompt negative temperature coefficient, very low fission product release, and high temperature capability. Eleven of these Sixty reactors are conversions from plate fuel to TRIGA fuel which were made as a result of these advantages. With only a few exceptions, TRIGA reactors have always used low-enriched uranium (LEU) fuel with an enrichment of 19.9%. The exceptions have either been converted from the standard low-enriched fuel to the 70% enriched FLIP fuel in order to achieve extended lifetime, or are higher powered reactors which were designed for long life using 93%-enriched uranium during the time when the use and export of highly enriched uranium (HEU) was not restricted. The advent of international policies focusing attention on nonproliferation and safeguards made the HEU fuels obsolete. General Atomic immediately undertook a development effort (nearly two years ago) in order to be in a position to comply with these policies for all future export sales and also to provide a low-enriched alternative to fully enriched plate-type fuels. This important work was subsequently partially supported by the U.S. Department of Energy. The laboratory and production tests have shown that higher uranium densities can be achieved to compensate for reducing the enrichment to 20%, and that the fuels maintain the characteristics of the very thoroughly proven standard TRIGA fuels. In May of 1978, General Atomic announced that these fuels were available for TRIGA reactors and for plate-type reactors with power levels up to 15 MW with General Atomic's standard commercial warranty

  10. Denitrifiers in the surface zone are primarily responsible for the nitrous oxide emission of dairy manure compost

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Koki, E-mail: k_maeda@affrc.go.jp [Dairy Research Division, National Agricultural Research Center for Hokkaido Region, National Agricultural and Food Research Organization, 1 Hitsujigaoka, Sapporo 062-8555 (Japan); Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Toyoda, Sakae [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Hanajima, Dai [Dairy Research Division, National Agricultural Research Center for Hokkaido Region, National Agricultural and Food Research Organization, 1 Hitsujigaoka, Sapporo 062-8555 (Japan); Yoshida, Naohiro [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

    2013-03-15

    Highlights: ? Nitrous oxide (N{sub 2}O) productions of each compost zones were compared. ? The pile surface emitted significant fluxes of N{sub 2}O. ? The isotopic signature of N{sub 2}O from surface and NO{sub 2}{sup ?} amended core were different. ? The denitrifying gene abundance was significantly higher in pile surface than the pile core. -- Abstract: During the dairy manure composting process, significant nitrous oxide (N{sub 2}O) emissions occur just after the pile turnings. To understand the characteristics of this N{sub 2}O emission, samples were taken from the compost surface and core independently, and the N{sub 2}O production was monitored in laboratory incubation experiments. Equal amounts of surface and core samples were mixed to simulate the turning, and the {sup 15}N isotope ratios within the molecules of produced N{sub 2}O were analyzed by isotopomer analysis. The results showed that the surface samples emitted significant levels of N{sub 2}O, and these emissions were correlated with NO{sub x}{sup ?}-N accumulation. Moreover, the surface samples and surface-core mixed samples incubated at 30 °C produced N{sub 2}O with a low site preference (SP) value (?0.9 to 7.0‰) that was close to bacteria denitrification (0‰), indicating that denitrifiers in the surface samples are responsible for this N{sub 2}O production. On the other hand, N{sub 2}O produced by NO{sub 2}{sup ?}-amended core samples and surface samples incubated at 60 °C showed unrecognized isotopic signatures (SP = 11.4–20.3‰). From these results, it was revealed that the N{sub 2}O production occurring just after the turnings was mainly derived from bacterial denitrification (including nitrifier denitrification) of NO{sub x}{sup ?}-N under mesophilic conditions, and surface denitrifying bacteria appeared to be the main contributor to this process.

  11. Denitrifiers in the surface zone are primarily responsible for the nitrous oxide emission of dairy manure compost

    International Nuclear Information System (INIS)

    Highlights: ? Nitrous oxide (N2O) productions of each compost zones were compared. ? The pile surface emitted significant fluxes of N2O. ? The isotopic signature of N2O from surface and NO2? amended core were different. ? The denitrifying gene abundance was significantly higher in pile surface than the pile core. -- Abstract: During the dairy manure composting process, significant nitrous oxide (N2O) emissions occur just after the pile turnings. To understand the characteristics of this N2O emission, samples were taken from the compost surface and core independently, and the N2O production was monitored in laboratory incubation experiments. Equal amounts of surface and core samples were mixed to simulate the turning, and the 15N isotope ratios within the molecules of produced N2O were analyzed by isotopomer analysis. The results showed that the surface samples emitted significant levels of N2O, and these emissions were correlated with NOx?-N accumulation. Moreover, the surface samples and surface-core mixed samples incubated at 30 °C produced N2O with a low site preference (SP) value (?0.9 to 7.0‰) that was close to bacteria denitrification (0‰), indicating that denitrifiers in the surface samples are responsible for this N2O production. On the other hand, N2O produced by NO2?-amended core samples and surface samples incubated at 60 °C showed unrecognized isotopic signatures (SP = 11.4–20.3‰). From these results, it was revealed that the N2O production occurring just after the turnings was mainly derived from bacterial denitrification (including nitrifier denitrification) of NOx?-N under mesophilic conditions, and surface denitrifying bacteria appeared to be the main contributor to this process

  12. Diversity, Abundance, and Distribution of nirS-Harboring Denitrifiers in Intertidal Sediments of the Yangtze Estuary.

    Science.gov (United States)

    Zheng, Yanling; Hou, Lijun; Liu, Min; Gao, Juan; Yin, Guoyu; Li, Xiaofei; Deng, Fengyu; Lin, Xianbiao; Jiang, Xiaofen; Chen, Fei; Zong, Haibo; Zhou, Junliang

    2015-07-01

    Denitrification plays a critical role in nitrogen removal in estuarine and coastal ecosystems. In this study, the community composition, diversity, abundance, and distribution of cytochrome cd1-type nitrite reductase gene (nirS)-harboring denitrifiers in intertidal sediments of the Yangtze Estuary were analyzed using polymerase chain reaction (PCR)-based clone libraries and quantitative PCR techniques. Clone library analysis showed that the nirS-encoding bacterial biodiversity was significantly higher at the lower salinity sites than at the higher salinity sites. However, there was no significant seasonal difference in the nirS gene diversity between summer and winter. Phylogenetic analysis revealed that the nirS-harboring denitrifier communities at the study area had distinctive spatial heterogeneity along the estuary. At the lower salinity sites, the nirS-harboring bacterial community was co-dominated by clusters III and VII; while at the higher salinity sites, it was dominated by cluster I. Canonical correspondence analysis indicated that the community compositions of nirS-type denitrifiers were significantly correlated with salinity, ammonium, and nitrate. Quantitative PCR results showed that the nirS gene abundance was in the range of 1.01 × 10(6) to 9.00 × 10(7) copies per gram dry sediment, without significant seasonal variation. Among all the environmental factors, the nirS gene abundance was only significantly related to the change of salinity. These results can extend our current knowledge about the composition and dynamics of denitrification microbial community in the estuarine ecosystem. PMID:25592637

  13. Anaerobic activation of p-cymene in denitrifying betaproteobacteria: methyl group hydroxylation versus addition to fumarate.

    Science.gov (United States)

    Strijkstra, Annemieke; Trautwein, Kathleen; Jarling, René; Wöhlbrand, Lars; Dörries, Marvin; Reinhardt, Richard; Drozdowska, Marta; Golding, Bernard T; Wilkes, Heinz; Rabus, Ralf

    2014-12-01

    The betaproteobacteria "Aromatoleum aromaticum" pCyN1 and "Thauera" sp. strain pCyN2 anaerobically degrade the plant-derived aromatic hydrocarbon p-cymene (4-isopropyltoluene) under nitrate-reducing conditions. Metabolite analysis of p-cymene-adapted "A. aromaticum" pCyN1 cells demonstrated the specific formation of 4-isopropylbenzyl alcohol and 4-isopropylbenzaldehyde, whereas with "Thauera" sp. pCyN2, exclusively 4-isopropylbenzylsuccinate and tentatively identified (4-isopropylphenyl)itaconate were observed. 4-Isopropylbenzoate in contrast was detected with both strains. Proteogenomic investigation of p-cymene- versus succinate-adapted cells of the two strains revealed distinct protein profiles agreeing with the different metabolites formed from p-cymene. "A. aromaticum" pCyN1 specifically produced (i) a putative p-cymene dehydrogenase (CmdABC) expected to hydroxylate the benzylic methyl group of p-cymene, (ii) two dehydrogenases putatively oxidizing 4-isopropylbenzyl alcohol (Iod) and 4-isopropylbenzaldehyde (Iad), and (iii) the putative 4-isopropylbenzoate-coenzyme A (CoA) ligase (Ibl). The p-cymene-specific protein profile of "Thauera" sp. pCyN2, on the other hand, encompassed proteins homologous to subunits of toluene-activating benzylsuccinate synthase (termed [4-isopropylbenzyl]succinate synthase IbsABCDEF; identified subunits, IbsAE) and protein homologs of the benzylsuccinate ?-oxidation (Bbs) pathway (termed BisABCDEFGH; all identified except for BisEF). This study reveals that two related denitrifying bacteria employ fundamentally different peripheral degradation routes for one and the same substrate, p-cymene, with the two pathways apparently converging at the level of 4-isopropylbenzoyl-CoA. PMID:25261521

  14. Denitrifying and diazotrophic community responses to artificial warming in permafrost and tallgrass prairie soils.

    Science.gov (United States)

    Penton, Christopher R; St Louis, Derek; Pham, Amanda; Cole, James R; Wu, Liyou; Luo, Yiqi; Schuur, E A G; Zhou, Jizhong; Tiedje, James M

    2015-01-01

    Increasing temperatures have been shown to impact soil biogeochemical processes, although the corresponding changes to the underlying microbial functional communities are not well understood. Alterations in the nitrogen (N) cycling functional component are particularly important as N availability can affect microbial decomposition rates of soil organic matter and influence plant productivity. To assess changes in the microbial component responsible for these changes, the composition of the N-fixing (nifH), and denitrifying (nirS, nirK, nosZ) soil microbial communities was assessed by targeted pyrosequencing of functional genes involved in N cycling in two major biomes where the experimental effect of climate warming is under investigation, a tallgrass prairie in Oklahoma (OK) and the active layer above permafrost in Alaska (AK). Raw reads were processed for quality, translated with frameshift correction, and a total of 313,842 amino acid sequences were clustered and linked to a nearest neighbor using reference datasets. The number of OTUs recovered ranged from 231 (NifH) to 862 (NirK). The N functional microbial communities of the prairie, which had experienced a decade of experimental warming were the most affected with changes in the richness and/or overall structure of NifH, NirS, NirK and NosZ. In contrast, the AK permafrost communities, which had experienced only 1 year of warming, showed decreased richness and a structural change only with the nirK-harboring bacterial community. A highly divergent nirK-harboring bacterial community was identified in the permafrost soils, suggesting much novelty, while other N functional communities exhibited similar relatedness to the reference databases, regardless of site. Prairie and permafrost soils also harbored highly divergent communities due mostly to differing major populations. PMID:26284038

  15. Simultaneous electricity generation and pollutant removal in microbial fuel cell with denitrifying biocathode over nitrite

    International Nuclear Information System (INIS)

    Highlights: • An MFC was successfully started up using nitrite as cathodic electron acceptor. • The optimal HRT was deemed to be 8 h in this study. • The suitable temperature for power generation was found to be 20 °C. • The suitable temperature for pollutant removal was found to be 25 °C. • Free buffer led to 50% decrease of TN removal rate and power generation. - Abstract: The influences of hydraulic retention time, temperature and free buffer on the performance of short-cut denitrifying microbial fuel cell were investigated after it was successfully started up using nitrite as the cathodic electron acceptor. The results revealed that a power density of 8.3 ± 0.5 W m?3 NC was obtained after 15 days operation. The desirable hydraulic retention time was found in this study to be 8 h, with a COD removal rate of 2.117 ± 0.006 kg m?3 NC d?1 and a total nitrogen removal rate of 0.041 ± 0.002 kg m?3 NC d?1, respectively. It demonstrated that temperature had different effects on the electricity generation and pollutant removal performance of microbial fuel cell. The suitable temperature for power generation and pollutant removal was found to be 20 °C and 25 °C, respectively. Free buffer led to 50% decrease of both total nitrogen removal rate and power density of microbial fuel cell compared to that with phosphate buffer solution addition. The optimal total nitrogen removal rate obtained in the case with sodium azide addition (0.075 ± 0.008 kg m?3 NC d?1) increased by 50% as compared to that without sodium azide addition. It suggested that abolishing oxygen or inhibiting nitrite oxidizing bacteria would favor nitrogen removal

  16. Structure of a new azurin from the denitrifying bacterium Alcaligenes xylosoxidans at high resolution.

    Science.gov (United States)

    Dodd, F E; Hasnain, S S; Abraham, Z H; Eady, R R; Smith, B E

    1995-11-01

    It has been reported previously that Alcaligenes xylosoxidans (NC1MB 11015) grown under denitrifying conditions produces two azurins instead of the single previously identified azurin [Dodd, Hasnain, Hunter, Abraham, Debenham, Kanzler, Eldridge, Eady, Ambler & Smith (1995). Biochemistry. In the press]. The new azurin, called azurin II, has been crystallized as blue elongated rectangular prisms with the tetragonal space group P4(1)22 and unit-cell parameters a = b = 52.65, c = 100.63 A. X-ray crystallographic data extending to 1.9 A resolution were collected by the Weissenberg method using 200 x 400 mm image plates and synchrotron X-rays of wavelength 0.97 A. The three-dimensional structure of azurin II has been solved by the molecular-replacement method using the structure of azurin from Alcaligenes denitrificans NCTC 8582 with which this new azurin shows a close homology. The quality of the initial map was sufficient to predict a number of sequence differences. The model is currently refined to an R-factor of 18.8% with X-ray data between 8.5 and 1.9 A. The final model of 961 protein atoms, one Cu atom and 50 water molecules has r.m.s. deviations from ideality of 0.009 A for bond lengths and 1.7 degrees for bond angles. The overall structure is similar to that of the azurin from A. denitrificans NCTC 8582. It has a beta-barrel structure with the Cu atom located near the top end of the molecule. The Cu atom is coordinated to Ndelta of His46 and His117 at 2.02 A and to Sgamma of Cys112 at 2.12 A, while the carbonyl O atom of Gly45 and Sdelta atom of Met121 provide the additional interactions at 2.75 and 3.26 A, respectively. PMID:15299774

  17. Diversity of Nitrate-Reducing and Denitrifying Bacteria in a Marine Aquaculture Biofilter and their Response to Sulfide

    DEFF Research Database (Denmark)

    Krieger, Bärbel; Schwermer, Carsten U.; Rezakhani, Nastaran; Horn, Marcus A.; Gieseke, Armin; Cytryn, Eddie; Dror, Minz; van Rijn, Jaap; Drake, Harold L.; Schramm, Andreas

    2006-01-01

    DIVERSITY OF NITRATE-REDUCING AND DENITRIFYING BACTERIA IN A MARINE AQUACULTURE BIOFILTER AND THEIR RESPONSE TO SULFIDE B.U. Krieger 1,5, C. Schwermer 2, N. Rezakhani 5, M.A. Horn 1, A. Gieseke 2, E. Cytryn 3, D. Minz 3, J. van Rijn 4, H.L. Drake 1, A. Schramm 5 1 Dept. of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany; 2 Max Planck Institute for Marine Microbiology, Bremen, Germany; 3 Institute for Soil, Water and Environmental Sciences, ARO, The Volcani Center, Bet Dagan, I...

  18. Functional diversity in the denitrifying biofilm of the methanol-fed marine denitrification system at the Montreal Biodome.

    Science.gov (United States)

    Auclair, Julie; Parent, Serge; Villemur, Richard

    2012-05-01

    Nitrate is a serious problem in closed-circuit public aquariums because its accumulation rapidly becomes toxic to many lifeforms. A moving bed biofilm denitrification reactor was installed at the Montreal Biodome to treat its 3,250-m(3) seawater system. Naturally occurring microorganisms from the seawater affluent colonized the reactor carriers to form a denitrifying biofilm. Here, we investigated the functional diversity of this biofilm by retrieving gene sequences related to narG, napA, nirK, nirS, cnorB, and nosZ. A total of 25 sequences related to these genes were retrieved from the biofilm. Among them, the corresponding napA1, nirK1, cnorB9, and nosZ3 sequences were identical to the corresponding genes found in Hyphomicrobium sp. NL23 while the narG1 and narG2 sequences were identical to the two corresponding narG genes found in Methylophaga sp. JAM1. These two bacterial strains were previously isolated from the denitrifying biofilm. To assess the abundance of denitrifiers and nitrate respirers in the biofilm, the gene copy number of all the narG, napA, nirS, and nirK sequences found in biofilm was determined by quantitative PCR. napA1, nirK1, narG1, and narG2, which were all associated with either Methylophaga sp. JAM1 or Hyphomicrobium sp. NL23, were the most abundant genes. The other genes were 10 to 10,000 times less abundant. nirK, cnorB, and nosZ but not napA transcripts from Hyphomicrobium sp. NL23 were detected in the biofilm, and only the narG1 transcripts from Methylophaga sp. JAM1 were detected in the biofilm. Among the 19 other genes, the transcripts of only two genes were detected in the biofilm. Our results show the predominance of Methylophaga sp. JAM1 and Hyphomicrobium sp. NL23 among the denitrifiers detected in the biofilm. The results suggest that Hyphomicrobium sp. NL23 could use the nitrite present in the biofilm generated by nitrate respirers such as Methylophaga sp. JAM1. PMID:22006549

  19. Chromatin enrichment for proteomics

    OpenAIRE

    Kustatscher, Georg; Wills, Karen L. H.; Furlan, Cristina; RAPPSILBER, JURI

    2014-01-01

    During interphase, chromatin hosts fundamental cellular processes, such as gene expression, DNA replication and DNA damage repair. To analyze chromatin on a proteomic scale, we have developed chromatin enrichment for proteomics (ChEP), which is a simple biochemical procedure that enriches interphase chromatin in all its complexity. It enables researchers to take a ‘snapshot’ of chromatin and to isolate and identify even transiently bound factors. In ChEP, cells are fixed with formaldehyde; su...

  20. Uranium enrichment technology

    International Nuclear Information System (INIS)

    A comparison of different enrichment technologies and their economic aspects offers guiding information on criteria for selecting plants still to be erected. The diffusion, centrifuge, and separation nozzle methods are considered as well as the so-called South-African method and isotope separation by means of laser light. The existing enrichment plants, those under construction, and those being planned justify the assumption that there can be no real lack of separation capacity within the next ten years. (orig.)

  1. Enrich Project Final Report

    OpenAIRE

    Nixon, William

    2010-01-01

    The Enrich project was a 12 month JISC project funded as part of the Inf11 Programme (2009-11). It was conducted in partnership by the Library, Research and Enterprise and IT Services – with additional technical support from EPrints Services. This interdepartmental approach was critical to the success of the project and the repository’s long term sustainability as an institutional [not simply Library] service. At its heart, Enrich provided a clear focus for the integration and enhance...

  2. Lax Diagrams and Enrichment

    OpenAIRE

    Bacard, Hugo V.

    2012-01-01

    We introduce a new type of weakly enriched categories over a given symmetric monoidal model category M; these are called Co-Segal categories. Their definition derives from the philosophy of classical (enriched) Segal categories. We study their homotopy theory by giving a model structure on them. One of the motivations of introducing these structure was to have an alternative definition of higher linear categories following Segal-like methods.

  3. Enrichment bei Laborhunden

    OpenAIRE

    Hubert, Ilona

    2004-01-01

    The subject of the previous study was which toys and which bedding locations are preferred by laboratory dogs and how these enrichment objects influence the behaviour of the animals. Therefore preference tests were made. Furthermore effects on the behaviour of the dogs were compared after providing certain bedding locations as enrichment in relation to the precondition. A total of 21 Beagles took part in the study. The preference tests were carried out with three groups with a total of 12 ...

  4. Isolation of the {epsilon}-caprolactam denitrifying bacteria from a wastewater treatment system manufactured with acrylonitrile-butadiene-styrene resin

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.-C. [Department of Environmental Engineering, Hungkuang University, Shalu, Taichung 433, Taiwan (China)]. E-mail: chunchin@sunrise.hk.edu.tw; Lee, C.-M. [Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan (China)

    2007-06-25

    {epsilon}-Caprolactam has high COD and toxicity, so its discharge to natural water and soil systems may lead to an adverse environmental effect on water quality, endangering public health and welfare. This investigation attempts to isolate {epsilon}-caprolactam denitrifying bacteria from a wastewater treatment system manufactured with acrylonitrile-butadiene-styrene (ABS) resin. The goal is to elucidate the effectiveness of isolated pure strain and ABS mixed strains in treating {epsilon}-caprolactam from synthetic wastewater. The results reveal that Paracoccus versutus MDC-3 was isolated from the wastewater treatment system manufactured with ABS resin. The ABS mixed strains and P. versutus MDC-3 can consume up to 1539 mg/l {epsilon}-caprolactam to denitrify from synthetic wastewater. Complete {epsilon}-caprolactam removal depended on the supply of sufficient electron acceptors (nitrate). Strain P. versutus MDC-3, Hyphomicrobium sp. HM, Methylosinus pucelana and Magnetospirillum sp. CC-26 are related closely, according to the phylogenetic analyses of 16S rDNA sequences.

  5. Estimate of denitrifying microbiota in tertiary sewage treatment and kinetics of the denitrification process using different sources of carbon

    Directory of Open Access Journals (Sweden)

    Marchetto Margarida

    2003-01-01

    Full Text Available A study of the kinetics of denitrification was carried out in the laboratory based on the quantification of N2O, the final product of the activity of denitrifying microorganisms, when the enzymatic reduction of N2O to N2 was blocked by acetylene. Concentrated mixed liquor (sludge from a reactor with intermittent aeration used for sewage treatment was used as the inoculum, while methanol, acetic acid, glucose, effluent sewage from an anaerobic fluidized bed reactor and synthetic substrate simulating domestic sewage were used as carbon sources. The mean concentration of nitrate was 20 mg/L. Maxima of N2O production and NO3- consumption occurred between 0.5h and 2.0h of incubation using all the carbon sources, which characterized the denitrification process. Acetic acid and methanol were responsible for the highest rates of N2O production. The estimated number of denitrifying microorganisms in the reactor with intermittent aeration, using the MPN technique, varied from 10(9 to 10(10 MPN/g VSS, indicating a high potential for the occurrence of denitrification.

  6. Effects of elevated CO2 concentrations on denitrifying and nitrifying popualtions at terrestrial CO2 leakeage analogous sites

    Science.gov (United States)

    Christine, Dictor Marie; Catherine, Joulian; Valerie, Laperche; Stephanie, Coulon; Dominique, Breeze

    2010-05-01

    CO2 capture and geological storage (CCS) is recognized to be an important option for carbon abatement in Europe. One of the risks of CCS is the leakage from storage site. A laboratory was conducted on soil samples sampled near-surface from a CO2 leakage analogous site (Latera, Italy) in order to evaluate the impact of an elevated soil CO2 concentration on terrestrial bacterial ecosystems form near surface terrestrial environments and to determine a potential bacterial indicator of CO2 leakage from storage site. Surveys were conducted along a 50m long transect across the vent centre, providing a spectrum of CO2 flux rates, soil gas concentrations and compositions (Beaubien et al., 2007). A bacterial diversity studies, performed by CE-SSCP technique, on a soil profile with increasing CO2 soil concentrations (from 0.3% to 100%) showed that a change on bacterial diversity was noted when CO2 concentration was above 50 % of CO2. From this result, 3 soil samples were taken at 70 cm depth in 3 distinct zones (background soil CO2 content, soil CO2 content of 20% and soil CO2 content of 50%). Then theses soil samples were incubated under closed jars flushed with different air atmospheres (20, 50 and 90 % of CO2) during 18 months. At initial, 3, 6, 12 and 18 months, some soil samples were collected in order to estimate the denitrifying, nitrifying activities as a function of CO2 concentration content and times. Theses enzymatic activities were chosen because one occurs under anaerobic conditions (denitrification) and the other occurs under aerobic conditions (nitrification). Both of them were involved in the nitrogen cycle and are major actors of soil function and groundwater quality preservation. Metabolic diversity using BIOLOG Ecoplates was determined on every soil samples. Physico-chemical parameters (e.g. pH, bulk chemistry, mineralogy) were analyzed to have some information about the evolution of the soil during the incubation with increasing soil CO2 concentrations. Statistical analyses were performed to correlate microbiological measures and physico-chemical parameters. For the soil sampled in a zone with background CO2 content, incubation under an atmosphere with 20% of CO2, induce a sharp decrease of denitrifying activity after 6 months of incubation and only after 3 months with an atmosphere of 50% of CO2. On the contrary, concerning the soil sampled in a zone with 25.5% of CO2, incubation with an atmosphere of 50% has no effect on denitrifying activity and moreover this activity was stimulated with an atmosphere of 90% of CO2.Last, with the soil sampled in an area with 65.8% of CO2, denitrifying activity was negatively impacted from the 3th month of incubation with 90% CO2.and the activity was 2 fold lower after 12th of incubation. Concerning the nitrifying activity, soil sampled in an area with background CO2 content, this one remains little affected by increasing CO2 incubation. At initial times, soil sampled in the areas with 25.5 and 65.8 % of CO2 showed low level of nitrifying activities and further CO2 incubations have no effect on these activities. At the end, denitrifying activities seems to be more sensitive to CO2 concentrations evolution in the soil. More studies need to be done as incubation with lower CO2 content (affect the near-surface bacterial activities and identify a possible candidate of CO2 leakage from deep reservoirs.

  7. The competitive enrichment market

    International Nuclear Information System (INIS)

    With the enactment of the ''Private Ownership of Special Nuclear Materials Act'' in 1964, the U.S. Government made provisions to enter into the uranium enrichment services business. Since nuclear power was in its infancy and the Government was promoting its growth as well as trying to help U.S. industry sell reactors overseas, the initial contracts (Requirements Contracts) for enrichment services placed most of the risks associated with the supplying of the services on the Government. Projections of nuclear power additions continued to grow and in 1972 the Atomic Energy Commission (AEC) stopped contracting under Requirements Contracts in order to study which mode of contracting best suited the commercial development of the industry. In mid-1973, the AEC introduced the Long-Term Fixed Commitment (LTFC) contract which shifted the risk to the customer. By mid-1974, AEC had contracts which completely used the enrichment capacity of its complex and refused to accept requests for additional contracts. This action further convinced European nations that they should continue to develop their own enrichment capacity and resulted in the EURODIF and URENCO projects. Before this time the U.S. supplied 100% of the world market for enriching services

  8. Oxygen enrichment incineration

    International Nuclear Information System (INIS)

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested

  9. Uranium enrichment in Europe

    International Nuclear Information System (INIS)

    Until the mid 1970's, the USA had a monopoly of separation work. There is now sufficient capacity at the Eurodif and Urenco plants for fully servicing Europe, but the Americans still have a large proportion of the European market. In 1984/85, the international market was determined by a series of basic decisions by the American market leader, which in turn were determined by the world-wide marketing activities of the European concerns Eurodif and Urenco. The author deals with the present situation in the world market for separation work, the recent decisions by the US Department of Energy (DOE) in enrichment technology, the setting to work of the enrichment plant at Urenco Germany at Gronau, the successes of the Urenco centrifuge technique and the state of laser enrichment. (orig.)

  10. Oxygen enrichment incineration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested.

  11. Centrifuge enrichment program

    International Nuclear Information System (INIS)

    Exxon Nuclear has been active in privately funded research and development of centrifuge enrichment technology since 1972. In October of 1975, Exxon Nuclear submitted a proposal to design, construct, and operate a 3000-MT SWU/yr centrifuge enrichment plant, under the provisions of the proposed Nuclear Fuel Assurance Act of 1975. The U.S. Energy Research and Development Administration (ERDA) accepted the proposal as a basis for negotiation. It was proposed to build a 1000-MT SWU/yr demonstration increment to be operational in 1982; and after successful operation for about one year, expand the facilities into a 3000-MT SWU/yr plant. As part of the overall centrifuge enrichment plant, a dedicated centrifuge manufacturing plant would be constructed; sized to support the full 3000-MT SWU/yr plant. The selection of the centrifuge process by Exxon Nuclear was based on an extremely thorough evaluation of current and projected enrichment technology; results show that the technology is mature and the process will be cost effective. The substantial savings in energy (about 93%) from utilization of the centrifuge option rather than gaseous diffusion is a compelling argument. As part of this program, Exxon Nuclear has a large hardware R and D program, plus a prototype centrifuge manufacturing capability in Malta, New York. To provide a full-scale machine and limited cascade test capability, Exxon Nuclear is constructing a $4,000,000 Centrifuge Test Facility in Richland, Washington. This facility was to initiate operations in the Fall of 1976. Exxon Nuclear is convinced that the centrifuge enrichment process is the rational selection for emergence of a commercial enrichment industry

  12. Advanced uranium enrichment processes

    International Nuclear Information System (INIS)

    Three advanced Uranium enrichment processes are dealt with in the report: AVLIS (Atomic Vapour LASER Isotope Separation), MLIS (Molecular LASER Isotope Separation) and PSP (Plasma Separation Process). The description of the physical and technical features of the processes constitutes a major part of the report. If further presents comparisons with existing industrially used enrichment technologies, gives information on actual development programmes and budgets and ends with a chapter on perspectives and conclusions. An extensive bibliography of the relevant open literature is added to the different subjects discussed. The report was drawn up by the nuclear research Centre (CEA) Saclay on behalf of the Commission of the European Communities

  13. Enriching the Catalog

    Science.gov (United States)

    Tennant, Roy

    2004-01-01

    After decades of costly and time-consuming effort, nearly all libraries have completed the retrospective conversion of their card catalogs to electronic form. However, bibliographic systems still are really not much more than card catalogs on wheels. Enriched content that Amazon.com takes for granted--such as digitized tables of contents, cover…

  14. Prospects for uranium enrichment

    International Nuclear Information System (INIS)

    The biggest technological barrier to practical laser enrichment of U isotopes is the lack of suitable lasers. The major motivation behind studies of laser-induced photochemical enrichment of uranium is the potential efficiency of the technique. A gaseous-diffusion plant requires ten million times more energy to separate fissionable uranium-235 from the more-common uranium-238 than the theoretical minimum of 60 joules per gram calculated from the entropy of mixing one gram of 235U with 140 g of 238U. The centrifuge process requires only one-tenth the energy needed for gaseous diffusion, but laser techniques promise to be 100 times more efficient than the centrifuge. The laser approach also can provide higher enrichment factors per stage, thereby reducing energy requirements and size of a uranium-enrichment plant. It is noted that laser-induced isotope separation has been shown to be feasible with a variety of conceptually different approaches. The major challenge now is to build lasers with reliability and efficiency adequate to move the emphasis to economic feasibility

  15. Designing job enrichment projects.

    Science.gov (United States)

    Clakeley, G L

    1988-01-01

    This paper describes a management strategy for a job satisfaction program utilized in a large occupational therapy department. The goal of the program is to retain satisfied, productive employees and reduce attrition of therapists and assistants. The use of job enrichment projects for occupational therapy assistants will be presented with brief descriptions of two projects. PMID:23944880

  16. Job Enrichment in Extension.

    Science.gov (United States)

    Fourman, Louis S.; Jones, Jo

    1997-01-01

    Interviews with 10 participants in Ohio State University's job enrichment program for midcareer extension agents found that 5 returned to their same jobs after the experience but only 2 felt challenged/renewed. Part-time participation while working made it difficult to balance responsibilities. More information and a structured orientation were…

  17. Everyone Vegetarian, World Enriching

    OpenAIRE

    John Y. Wu

    2014-01-01

    This essay advocates global vegetarian diet. Firstly, seven personal health benefits and four global benefits of vegetarian dinners are specified to enrich the entire globe, and then, secondly, I explore concretely how to overcome internal hurdle and external hurdle, so as to effectively propagate vegetarian dinners throughout the world. Everyone wins, including animals!

  18. Diversity of Nitrate-Reducing and Denitrifying Bacteria in a Marine Aquaculture Biofilter and their Response to Sulfide

    DEFF Research Database (Denmark)

    Krieger, Bärbel; Schwermer, Carsten U.

    2006-01-01

    DIVERSITY OF NITRATE-REDUCING AND DENITRIFYING BACTERIA IN A MARINE AQUACULTURE BIOFILTER AND THEIR RESPONSE TO SULFIDE B.U. Krieger 1,5, C. Schwermer 2, N. Rezakhani 5, M.A. Horn 1, A. Gieseke 2, E. Cytryn 3, D. Minz 3, J. van Rijn 4, H.L. Drake 1, A. Schramm 5 1 Dept. of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany; 2 Max Planck Institute for Marine Microbiology, Bremen, Germany; 3 Institute for Soil, Water and Environmental Sciences, ARO, The Volcani Center, Bet Dagan, Israel; 4 Faculty of Agricultural, Food And Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, Israel; 5 Dept of Biological Sciences, Microbiology, University of Aarhus, Denmark Conventional aquaculture systems release nitrogen compounds and organic matter into marine environments. As an environmentally-friendly alternative, a zero-discharge mariculture system recently was developed containing a 3-stage biofilter for nitrification, denitrification/anaerobic sludge digestion, and sulfide oxidation. Sulfate reduction in the anaerobic part of the system leads to sulfide concentrations exceeding 5 mM, which may affect nitrate reduction and denitrification. Sulfide can inhibit nitrous oxide reductase, trigger a shift from denitrification to dissimilatory nitrate reduction to ammonium (DNRA), or be used as electron donor for nitrate reduction. The goal of this study was to identify and isolate nitrate-reducing and denitrifying bacteria from the biofilter and to investigate their response to sulfide concentrations relevant for the system. Almost 500 nitrate-consuming isolates were screened by 16S rRNA gene-RFLP; for each RFLP pattern representatives were sequenced. In total, 40 different strains were identified, some of them novel species, mostly affiliating with Alphaproteobacteria but also including Beta- and Gammaproteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. The diversity of the isolates was compared to the cultivation-independent diversity of nitrate-reducing and denitrifying bacteria based on narG and nosZ as functional marker genes. Growth experiments revealed great differences in sulfide-tolerance among isolates, ranging from < 50 µM to 5 mM; some strains were also able to oxidize sulfide. Increasing sulfide concentrations generally resulted in increased nitrous oxide production. Batch incubations of anaerobic sludge with 15N-nitrate confirmed the in situ relevance of these results and indicated a sulfide-induced shift from denitrification to DNRA.

  19. Availability of enrichment services

    International Nuclear Information System (INIS)

    The report summarizes major uncertainties which are likely to influence future demands for uranium isotopic enrichment. Since for the next decade the development of nuclear power will be largely concerned with the increment in demand the timely need for enrichment capacity will be particularly sensitive to assumptions about growth rates. Existing worldwide capacity together with capacities under construction will be sufficient well into the 1980's. However, long decision and construction leadtime, uncertainty as to future demand as well as other factors, specifically high capital need, all of which entail financial risks, create hindrances to a timely development of increment. The adequacy of current technology is well demonstrated in plant operation and new technology is under way. Technology is, however, not freely available on a purely commercial basis. Commercial willingness, which anticipates a limited degree of financial risk, is requesting both long term back-up from the utilities that would parallel their firm decisions on the acquisition of nuclear power units, and a protective government umbrella. This situation depends on the symbiotic relationship that exists between the nuclear power generating organizations, the enrichment undertakings and the governments involved. The report accordingly stresses the need for a more cooperative approach and this, moreover, at the multinational level. There is otherwise a risk that proper resources and financing means will not be allocated to the enrichment sector. Export limitations that request the highest degree of industrial processing of nuclear fuel, i.e. the compulsory enrichment of natural uranium, do not serve the interests of overall industrial efficiency

  20. Availability of enrichment services

    International Nuclear Information System (INIS)

    The report summarizes major uncertainties which are likely to influence future demands for uranium isotopic enrichment. Since for the next decade the development of nuclear power will be largely concerned with the increase in demand the need for enrichment capacity will then be particularly sensitive to assumptions about growth-rates. Existing world-wide capacity, together with capacities under construction, will be sufficient well into the 1980s. However, long decision and construction lead-time, uncertainty regarding future demand as well as other factors, specifically high capital need, all of which entail financial risks, create hindrances to a timely development of incremental capacity. The adequacy of current technology is well demonstrated in plant operation and new technology is under way. Technology is, however, not freely available on a purely commercial basis. Commercial willingness, which anticipates a limited degree of financial risk, requests both long-term back-up from the utilities that would parallel their firm decisions on the acquisition of nuclear power units, and a protective government umbrella. This situation depends on the symbiotic relationship that exists between the nuclear power generating organizations, the enrichment undertakings and the governments involved. The report accordingly stresses the need for a more co-operative approach and this, moreover, at the multinational level. There is otherwise a risk that proper resources and financing means will not be allocated to the enrichment sector. Export limitations that lead to a high degree of industrial processing of nuclear fuel, i.e. the obligatory enrichment of natural uranium, do not serve the interests of overall industrial efficiency. (author)

  1. Characterization of a murine neuron-enriched model of primary trigeminal ganglia cultures to study the interferon- ? antiviral effect against Herpes Simplex Virus type 1 / Caracterización de un modelo murino de cultivos primarios de ganglio trigeminal enriquecido en neuronas para el estudio del efecto antiviral del interferón- ? frente al virus Herpes simple tipo 1

    Scientific Electronic Library Online (English)

    Ana Maria, Low-Calle; Jeanette, Prada-Arismendy; Jaime E., Castellanos.

    2014-06-01

    Full Text Available Objetivo: Caracterizar un cultivo primario de ganglio trigeminal (GT) enriquecido en neuronas y evaluar la expresión de interferón- y su actividad frente a la infección con Herpes simple tipo 1 (HSV-1). Materiales y métodos: El porcentaje de neuronas fue determinado por inmunocitoquímica para neurof [...] ilamento. Los cultivos fueron tratados con interferón- ? e infectados con HSV-1, y se cuantificaron las células positivas para antígeno viral por inmunocitoquímica y la expresión de interferón- ? por PCR cuantitativa. Resultados: El cultivo presentó un 15% de neuronas y 85% de células no neuronales. Se encontró efecto citopático, asociado a una alta diseminación de la infección (72,9% neuronas y 48,3% de células no neuronales positivas para antígeno viral). El interferón- ? evitó la aparición de efecto citopático y disminuyó las células infectadas a 16,7% en neuronas y a 7,8% las células no neuronales. La infección viral incrementó la expresión de transcritos de interferón- ? 18,2 veces a las 6 h de infección, mientras que a las 18 h post infección el tratamiento con interferón incrementó esta expresión 3,7 veces. Discusión: Los cultivos presentaron un 15% de neuronas, lo cual es 10 veces más que en otros cultivos reportados. Las células no neuronales representan el 85% de las células del cultivo, y se evidenció que todos los tipos de células se infectaron; similar a lo que ha sido reportado durante infecciones agudas in vivo . Adicionalmente, el interferón- ? disminuyó el porcentaje de células infectadas y evitó la aparición de efecto citopático, similar a lo que ha sido reportado en cultivos de GT porcino. Conclusiones: Se caracterizó un modelo de cultivo primario de GT enriquecido en neuronas. Interferón- ? protegió las células del efecto citopático y la diseminación viral mientras que la infección viral incrementó la expresión de interferón- ?. Por lo tanto, el interferón- ? ejerció un papel antiviral importante frente al HSV-1 en estos cultivos. Abstract in english Objective: To characterize a neuron-enriched primary TG culture and evaluate interferon- ? expression and activity after HSV-1 infection. Materials and methods: The percentage of neurons present in cultures was assessed by neurofilament immunocytochemistry. Cultures were treated with interferon- ? a [...] nd infected with HSV-1, then viral antigen positive cells were counted and interferon- ?expression was assessed by quantitative PCR. Results: The culture contained 15% neurons and 85% non-neuronal cells. A cytopathic effect was observed, associated with high viral spread (72.9% neurons and 48.3% non-neuronal cells were positive for viral antigen). Interferon- ? treatment impaired the cytopathic effect and decreased the infected neurons to 16.7% and infected non-neuronal cells to 7.8%. Viral infection at 6 h postinfection significantly increased the interferon- ? transcripts by 18.2 fold, while at 18 h postinfection Interferon pre-treatment in infected cultures increased interferon- ? transcription by 3.7 fold. Discussion: This culture model contained 15% neurons, which is 10 times higher compared to other reported cultures, and non-neuronal cells comprised 85% of cells in this culture. All types of cells were found to be infected, which is similar to that reported during acute infections in vivo . Additionally, interferon- ?decreased the infected cells, avoiding the cytopathic effect, which is similar to that reported in swine TG cultures. Conclusions: A neuron-enriched primary TG model was characterized. Interferon- ? treatment protected cells from cytopathic effects and viral spread, while viral infection up-regulated interferon- ? expression. This result means that interferon- ? exerts an important antiviral effect against HSV-1 in these cultures.

  2. Environmental enrichment for indoor cats: implementing enrichment.

    Science.gov (United States)

    Herron, Meghan E; Buffington, C A Tony

    2012-01-01

    In a previous article, we described our approach to implementation of effective environmental enrichment, which begins with the diagnosis of environmental features to determine how well they meet the behavior and welfare needs of indoor-housed cats. We formulate this diagnosis based on a pertinent history and physical evaluation. A pertinent history allows us to identify features of the cat and environment that may precipitate or contribute to observed behavioral and physical problems. Physical evaluation of the environment means determination of the presence and quality of physical and behavioral resources available to the cat. As discussed in the previous article, we organize the environment into five basic systems: physical, nutritional, social, elimination, and behavioral, and methodically investigate each one to identify any features that may benefit from improvement. Our first article offered practical means of meeting the environmental needs of cats within each system. The objective of this article is to present methods for reviewing the information obtained with the client and developing an effective implementation plan. Rather than blaming the client for any identified environmental shortcomings, we choose to emphasize areas of improvement that the client believes can be accomplished. Effective communication skills increase the probability of implementation of and adherence to the plan. PMID:22271468

  3. Transitions in nirS-type Denitrifier Diversity, Community Composition, and Biogeochemical Activity along the Chesapeake Bay Estuary

    Directory of Open Access Journals (Sweden)

    ChristopherAFrancis

    2013-08-01

    Full Text Available Chesapeake Bay, the largest estuary in North America, can be characterized as having steep and opposing gradients in salinity and dissolved inorganic nitrogen along the main axis of the Bay. In this study, the diversity of nirS gene fragments (encoding cytochrome cd1-type nitrite reductase, physical/chemical parameters, and benthic N2-fluxes were analyzed in order to determine how denitrifier communities and biogeochemical activity vary along the estuary salinity gradient. The nirS gene fragments were PCR-amplified, cloned, and sequenced from sediment cores collected at five stations. Sequence analysis of 96 to 123 nirS clones from each station revealed extensive overall diversity in this estuary, as well as distinct spatial structure in the nirS sequence distributions. Both nirS-based richness and community composition varied among stations, with the most dramatic shifts occurring between low-salinity (oligohaline and moderate-salinity (mesohaline sites. For four samples collected in April, the nirS-based richness, nitrate concentrations, and N2-fluxes all decreased in parallel along the salinity gradient from the oligohaline northernmost station to the highest salinity (polyhaline station near the mouth of the Bay. The vast majority of the 550 nirS sequences were distinct from cultivated denitrifiers, although many were closely related to environmental clones from other coastal and estuarine systems. Interestingly, 8 of the 172 OTUs identified accounted for 42% of the total nirS clones, implying the presence of a few dominant and many rare genotypes, which were distributed in a non-random manner along the salinity gradient of Chesapeake Bay. These data, comprising the largest dataset to investigate nirS clone sequence diversity from an estuarine environment, also provided information that was required for the development of nirS microarrays to investigate the interaction of microbial diversity, environmental gradients, and biogeochemical activity.

  4. Whole-Genome Transcriptional Analysis of Chemolithoautotrophic Thiosulfate Oxidation by Thiobacillus denitrificans Under Aerobic vs. Denitrifying Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Beller, H R; Letain, T E; Chakicherla, A; Kane, S R; Legler, T C; Coleman, M A

    2006-04-22

    Thiobacillus denitrificans is one of the few known obligate chemolithoautotrophic bacteria capable of energetically coupling thiosulfate oxidation to denitrification as well as aerobic respiration. As very little is known about the differential expression of genes associated with ke chemolithoautotrophic functions (such as sulfur-compound oxidation and CO2 fixation) under aerobic versus denitrifying conditions, we conducted whole-genome, cDNA microarray studies to explore this topic systematically. The microarrays identified 277 genes (approximately ten percent of the genome) as differentially expressed using Robust Multi-array Average statistical analysis and a 2-fold cutoff. Genes upregulated (ca. 6- to 150-fold) under aerobic conditions included a cluster of genes associated with iron acquisition (e.g., siderophore-related genes), a cluster of cytochrome cbb3 oxidase genes, cbbL and cbbS (encoding the large and small subunits of form I ribulose 1,5-bisphosphate carboxylase/oxygenase, or RubisCO), and multiple molecular chaperone genes. Genes upregulated (ca. 4- to 95-fold) under denitrifying conditions included nar, nir, and nor genes (associated respectively with nitrate reductase, nitrite reductase, and nitric oxide reductase, which catalyze successive steps of denitrification), cbbM (encoding form II RubisCO), and genes involved with sulfur-compound oxidation (including two physically separated but highly similar copies of sulfide:quinone oxidoreductase and of dsrC, associated with dissimilatory sulfite reductase). Among genes associated with denitrification, relative expression levels (i.e., degree of upregulation with nitrate) tended to decrease in the order nar > nir > nor > nos. Reverse transcription, quantitative PCR analysis was used to validate these trends.

  5. The Enriched Xenon Observatory

    International Nuclear Information System (INIS)

    The Enriched Xenon Observatory (EXO) experiment will search for neutrinoless double beta decay of 136Xe. The EXO Collaboration is actively pursuing both liquid-phase and gas-phase Xe detector technologies with scalability to the ton-scale. The search for neutrinoless double beta decay of 136Xe is especially attractive because of the possibility of tagging the resulting Ba daughter ion, eliminating all sources of background other than the two neutrino decay mode. EXO-200, the first phase of the project, is a liquid Xe time projection chamber with 200 kg of Xe enriched to 80% in 136Xe. EXO-200, which does not include Ba-tagging, will begin taking data in 2009, with two-year sensitivity to the half-life for neutrinoless double beta decay of 6.4x1025 years. This corresponds to an effective Majorana neutrino mass of 0.13 to 0.19 eV.

  6. South Australia, uranium enrichment

    International Nuclear Information System (INIS)

    The Report sets out the salient data relating to the establishment of a uranium processing centre at Redcliff in South Australia. It is conceived as a major development project for the Commonwealth, the South Australian Government and Australian Industry comprising the refining and enrichment of uranium produced from Australian mines. Using the data currently available in respect of markets, demand, technology and possible financial return from overseas sales, the project could be initiated immediately with hexafluoride production, followed rapidly in stages by enrichment production using the centrifuge process. A conceptual development plan is presented, involving a growth pattern that would be closely synchronised with the mining and production of yellowcake. The proposed development is presented in the form of an eight-and-half-year programme. Costs in this Report are based on 1975 values, unless otherwise stated. (Author)

  7. Centrifugal enrichment of sulfur isotopes

    International Nuclear Information System (INIS)

    This work contains the results of the research for the complete cycle of the centrifuge enrichment process of all sulfur isotopes. As a result of this work there was obtained, and made available (by centrifuge enrichment process), for the first time hundreds of grams of all the isotopes of sulfur to high enrichment. (author)

  8. Fostering Earth Science Inquiry From Within a Native Hawaiian Cultural Framework In O`ahu (Hawai`i) Through A Multidisciplinary Place-Based High School Summer Enrichment Program

    Science.gov (United States)

    Moxey, L.; Dias, R.; Legaspi, E.

    2010-12-01

    During the summer of 2010, twenty-five public high school students from underrepresented communities and ethnicities (Hawaiian, part-Hawaiian, S?moan, Filipino, Pacific Islander) in O`ahu (Hawai`i) participated in the M?lama Ke Ahupua`a (protecting our watershed) program. This rigorous three-week hands-on, place-based multidisciplinary program provided students with the opportunity of visiting the M?noa Valley watershed (O`ahu, Hawaii) for learning and experiencing the Earth Science System dynamics that comprises it, while simultaneously exploring the significance of the ahupua`a (watershed) as related to native Hawaiian history and culture. While earning Hawaii DOE-approved academic credit, students utilized GPS/GIS technology, quantitative water quality testing equipment, and environmental monitoring tools for performing a watershed survey and water quality study of M?noa Stream (M?noa Valley) from its inception in the mountains, its advance through Honolulu’s urbanized areas, and its convergence with the Pacific Ocean. Through this hands-on field-based study, students documented changes in the watershed’s environment as reflected in declining water quality induced by anthropogenic pollution sources and urbanization. Students also visited relevant native Hawaiian cultural sites in M?noa, and explored their direct links with the historical sustainable usage of the watershed’s natural resources, both from a cultural and science-based perspective. Finally, traditional wa`a (native Hawaiian outrigger canoes) were used as both cultural resources for discussing ancient Polynesian exploration, as well as scientific research platforms for conducting near-shore reef surveys & assessments. This program served to promote not only Earth Science literacy and STEM skills, but also contributed to further environmental stewardship while fostering native Hawaiian & Polynesian cultural identities.

  9. Uranium enrichment by gas centrifuge

    International Nuclear Information System (INIS)

    After recalling the physical principles and the techniques of centrifuge enrichment the report describes the centrifuge enrichment programmes of the various countries concerned and compares this technology with other enrichment technologies like gaseous diffusion, laser, aerodynamic devices and chemical processes. The centrifuge enrichment process is said to be able to replace with advantage the existing enrichment facilities in the short and medium term. Future prospects of the process are also described, like recycled uranium enrichment and economic improvements; research and development needs to achieve the economic prospects are also indicated. Finally the report takes note of the positive aspect of centrifuge enrichment as far as safeguards and nuclear safety are concerned. 27 figs, 113 refs

  10. Detection of Mycobacterium tuberculosis in cerebrospinal fluid following immunomagnetic enrichment.

    OpenAIRE

    Mazurek, G H; Reddy, V.; Murphy, D.; T. Ansari

    1996-01-01

    The detection of Mycobacterium tuberculosis by culture of cerebrospinal fluid (CSF) is unacceptably slow. Low numbers of organisms and the presence of reaction inhibitors may prevent detection of M. tuberculosis by PCR. We used immunomagnetic enrichment to accelerate and enhance the detection of mycobacteria in CSF after demonstrating the utility of the method with pure suspensions. Growth was detected earlier in Bactec cultures of magnetically recovered mycobacteria than in untreated CSF (7 ...

  11. Evaluation of the microbial diversity in sequencing batch reactor treating linear alkylbenzene sulfonate under denitrifying and mesophilic conditions using swine sludge as inoculum

    Scientific Electronic Library Online (English)

    Iolanda Cristina Silveira, Duarte; Lorena Lima de, Oliveira; Dagoberto Yukio, Okada; Pierre Ferreira do, Prado; Maria Bernadete Amâncio, Varesche.

    2015-06-01

    Full Text Available The objective of this study was to evaluate the degradation of Linear Alkylbenzene Sulfonate (LAS) in anaerobic sequencing batch reactor (ASBR) under denitrifying conditions using swine sludge as inoculum. The reactor was operated for 104 days with synthetic substrate containing nitrate, and LAS was [...] added later (22 mg/L). Considering the added mass of the LAS, the adsorbed mass in the sludge and discarded along with the effluent, degradation of the surfactant at the end of operation was 87%, removal of chemical oxygen demand was 86% and nitrate was 98%. The bacterial community was evaluated by cutting the bands and sequencing of polymerase chain reaction (PCR) fragments and denaturing gradient gel electrophoresis (DGGE). The sequences obtained were related to the phylum Proteobacteria and the alpha-and beta-proteobacteria classes, these bacteria were probably involved in the degradation of LAS. The efficiently degraded LAS in the reactor was operated in batch sequences in denitrifying conditions.

  12. Effects of Heavy Metal Contamination upon Soil Microbes: Lead-induced Changes in General and Denitrifying Microbial Communities as Evidenced by Molecular Markers

    Directory of Open Access Journals (Sweden)

    Maria Begonia

    2008-12-01

    Full Text Available Lead (Pb is a common environmental contaminant found in soils. Unlike other metals, Pb has no biological role, and is potentially toxic to microorganisms. Effects of low (1 ppm and high (500-2000 levels of lead (Pb upon the soil microbial community was investigated by the PCR/DGGE analysis of the 16S and nirK gene markers, indicative of general microbial community and denitrifying community, respectively. Community analysis by use of those markers had shown that Pb has detectable effects upon the community diversity even at the lowest concentration tested. Analysis of sample diversity and similarity between the samples suggested that there are several thresholds crossed as metal concentration increase, each causing a substantial change in microbial diversity. Preliminary data obtained in this study suggest that the denitrifying microbial community adapts to elevated levels of Pb by selecting for metal-resistant forms of nitrite reductases.

  13. Evaluation of the microbial diversity in sequencing batch reactor treating linear alkylbenzene sulfonate under denitrifying and mesophilic conditions using swine sludge as inoculum

    Scientific Electronic Library Online (English)

    Iolanda Cristina Silveira, Duarte; Lorena Lima de, Oliveira; Dagoberto Yukio, Okada; Pierre Ferreira do, Prado; Maria Bernadete Amâncio, Varesche.

    Full Text Available The objective of this study was to evaluate the degradation of Linear Alkylbenzene Sulfonate (LAS) in anaerobic sequencing batch reactor (ASBR) under denitrifying conditions using swine sludge as inoculum. The reactor was operated for 104 days with synthetic substrate containing nitrate, and LAS was [...] added later (22 mg/L). Considering the added mass of the LAS, the adsorbed mass in the sludge and discarded along with the effluent, degradation of the surfactant at the end of operation was 87%, removal of chemical oxygen demand was 86% and nitrate was 98%. The bacterial community was evaluated by cutting the bands and sequencing of polymerase chain reaction (PCR) fragments and denaturing gradient gel electrophoresis (DGGE). The sequences obtained were related to the phylum Proteobacteria and the alpha-and beta-proteobacteria classes, these bacteria were probably involved in the degradation of LAS. The efficiently degraded LAS in the reactor was operated in batch sequences in denitrifying conditions.

  14. Heat Production by the Denitrifying Bacterium Pseudomonas fluorescens and the Dissimilatory Ammonium-Producing Bacterium Pseudomonas putrefaciens during Anaerobic Growth with Nitrate as the Electron Acceptor

    OpenAIRE

    Samuelsson, M.-O.; Cadez, P.; Gustafsson, L.

    1988-01-01

    The heat production rate and the simultaneous nitrate consumption and production and consumption of nitrite and nitrous oxide were monitored during the anaerobic growth of two types of dissimilatory nitrate reducers. Pseudomonas fluorescens, a denitrifier, consumed nitrate and accumulated small amounts of nitrite or nitrous oxide. The heat production rate increased steadily during the course of nitrate consumption and decreased rapidly concomitant with the depletion of the electron acceptors....

  15. Insights into the effect of soil pH on N2O and N2 emissions and denitrifier community size and activity.

    Czech Academy of Sciences Publication Activity Database

    ?uhel, Ji?í; Šimek, Miloslav; Laughlin, R.J.; Bru, D.; Chéneby, D.; Watson, C.J.; Philippot, L.

    2010-01-01

    Ro?. 76, ?. 6 (2010), s. 1870-1878. ISSN 0099-2240 R&D Projects: GA MŠk MEB020726; GA MŠk LC06066; GA AV ?R IAA600660605 Institutional research plan: CEZ:AV0Z60660521 Keywords : soil pH * N 2 O and N 2 emissions * denitrifier community Subject RIV: EH - Ecology, Behaviour Impact factor: 3.778, year: 2010

  16. Classification of positive blood cultures

    DEFF Research Database (Denmark)

    Gradel, Kim O; Knudsen, Inge Jenny Dahl; Arpi, Rolf Magnus; Ostergaard, Christian; Schønheyder, Henrik Carl; Søgaard, Mette

    2012-01-01

    ABSTRACT: BACKGROUND: Information from blood cultures is utilized for infection control, public health surveillance, and clinical outcome research. This information can be enriched by physicians assessments of positive blood cultures, which are, however, often available from selected patient groups or pathogens only. The aim of this work was to determine whether patients with positive blood cultures can be classified effectively for outcome research in epidemiological studies by the use of admin...

  17. Importance of pre-enrichment media for isolation of Salmonella spp. from swine and poultry

    DEFF Research Database (Denmark)

    Hoorfar, Jeffrey; Baggesen, Dorte Lau

    1998-01-01

    The performance of two new (1-day) culture methods, Salmonella Enrichment Broth (SEB) and Revive, and an alternative pre-enrichment broth, designated Universal pre-enrichment broth (UB), was compared to the internationally accepted buffered peptone water (BPW). The study was directed towards detection of Salmonella in 100 faecal samples from porcine and 100 neck-skin samples from poultry. The sensitivity (number of positive cases per method among all the positive cases) of the conventional pre-e...

  18. Enrichment of Thermophilic Propionate-Oxidizing Bacteria in Syntrophy with Methanobacterium thermoautotrophicum or Methanobacterium thermoformicicum

    OpenAIRE

    Stams, Alfons J M; Grolle, Katja C. F.; Frijters, Carla T. M.; Van Lier, Jules B.

    1992-01-01

    Thermophilic propionate-oxidizing, proton-reducing bacteria were enriched from the granular methanogenic sludge of a bench-scale upflow anaerobic sludge bed reactor operated at 55°C with a mixture of volatile fatty acids as feed. Thermophilic hydrogenotrophic methanogens had a high decay rate. Therefore, stable, thermophilic propionate-oxidizing cultures could not be obtained by using the usual enrichment procedures. Stable and reproducible cultivation was possible by enrichment in hydrogen-p...

  19. Modular enrichment measurement system for in-situ enrichment assay

    International Nuclear Information System (INIS)

    A modular enrichment measurement system has been designed and is in operation within General Electric's Nuclear Fuel Fabrication Facility for the in-situ enrichment assay of uranium-bearing materials in process containers. This enrichment assay system, which is based on the ''enrichment meter'' concept, is an integral part of the site's enrichment control program and is used in the in-situ assay of the enrichment of uranium dioxide (UO2) powder in process containers (five gallon pails). The assay system utilizes a commercially available modular counting system and a collimnator designed for compatability with process container transport lines and ease of operator access. The system has been upgraded to include a microprocessor-based controller to perform system operation functions and to provide data acquisition and processing functions. Standards have been fabricated and qualified for the enrichment assay of several types of uranium-bearing materials, including UO2 powders. The assay system has performed in excess of 20,000 enrichment verification measurements annually and has significantly contributed to the facility's enrichment control program

  20. Nitrogen Removal by a Fungal Aerobic Denitrifier of Penicillium Strain

    OpenAIRE

    Chaocheng Zhao; Weisi Li

    2012-01-01

    A kind of aerobic Penicillium that can remove ammonia, nitrite and nitrate was isolated through an improved bromothymol blue (BTB) selective culture medium method in this experiment and then the nitrogen removal by the strain was detailedly investigated. The results showed that this strain was able to make use of many kinds of organic carbon compounds as sole carbon source for the removal of the three types of inorganic nitrogen compounds but the way of removal was different. Ammonia was assi...

  1. Enrichment promotes learning in fish

    OpenAIRE

    Strand, David A.; Utne-Palm, Anne C.; Jakobsen, Per J.; Braithwaite, Victoria A.; Jensen, Knut Helge; Salvanes, Anne Gro Vea

    2010-01-01

    Captive birds and mammals reared in enriched rearing environments have been shown to behave more flexibly compared to animals reared in impoverished or plain environments. Recent evidence has shown that this is also true for fish; enrichment promotes faster recovery after a stressful experience, a higher propensity for exploration of novel areas and the development of more sophisticated social behaviour. Here we report how enrichment influences social learning in juvenile cod G...

  2. Enrichment of boron 10

    International Nuclear Information System (INIS)

    A isotopic separation pilot plant with five ion exchange columns interconnected in series were designed and built in the IEN. The columns are charged with a strong anionic resin in its alkaline form. The boric acid solution is introduced in the separation columns until it reaches a absorbing zone length which is sufficient to obtain the desired boron-10 isotopic concentration. The boric acid absorbing zone movement is provided by the injection of a diluted hydrochloric acid solution, which replace the boric acid throughout the columns. The absorbing zone equilibrium length is proportional to its total length. The enriched boron-10 and the depleted boron are located in the final boundary and in the initial position of the absorbing zones, respectively. (author)

  3. Changes in bacterial community structure correlate with initial operating conditions of a field-scale denitrifying fluidized bed reactor.

    Science.gov (United States)

    Hwang, C; Wu, W-M; Gentry, T J; Carley, J; Carroll, S L; Schadt, C; Watson, D; Jardine, P M; Zhou, J; Hickey, R F; Criddle, C S; Fields, M W

    2006-08-01

    High levels of nitrate are present in groundwater migrating from the former waste disposal ponds at the Y-12 National Security Complex in Oak Ridge, TN. A field-scale denitrifying fluidized bed reactor (FBR) was designed, constructed, and operated with ethanol as an electron donor for the removal of nitrate. After inoculation, biofilms developed on the granular activated carbon particles. Changes in the bacterial community of the FBR were evaluated with clone libraries (n = 500 partial sequences) of the small-subunit rRNA gene for samples taken over a 4-month start-up period. Early phases of start-up operation were characterized by a period of selection, followed by low diversity and predominance by Azoarcus-like sequences. Possible explanations were high pH and nutrient limitations. After amelioration of these conditions, diversification increased rapidly, with the appearance of Dechloromonas, Pseudomonas, and Hydrogenophaga sequences. Changes in NO3, SO4, and pH also likely contributed to shifts in community composition. The detection of sulfate-reducing-bacteria-like sequences closely related to Desulfovibrio and Desulfuromonas in the FBR have important implications for downstream applications at the field site. PMID:16292532

  4. Work Enrichment for Academic Libraries.

    Science.gov (United States)

    Martell, Charles; Untawale, Mercedes

    1983-01-01

    Explores important quality of work life strategy--job redesign--and discusses job enlargement and job enrichment. A case study of academic library personnel demonstrates how introduction of automated systems at University of California, Berkeley led to restructuring and enrichment of jobs. References and list of selected resources are appended.…

  5. New primers for detecting and quantifying denitrifying anaerobic methane oxidation archaea in different ecological niches.

    Science.gov (United States)

    Ding, Jing; Ding, Zhao-Wei; Fu, Liang; Lu, Yong-Ze; Cheng, Shuk H; Zeng, Raymond J

    2015-11-01

    The significance of ANME-2d in methane sink in the environment has been overlooked, and there was no any study evaluating the distribution of ANME-2d in the environment. New primers were thus needed to be designed for following research. In this paper, a pair of primers (DP397F and DP569R) was designed to quantify ANME-2d. The specificity and amplification efficiency of this primer pair were acceptable. PCR amplification of another pair of primers (DP142F and DP779R) generated a single, bright targeted band from the enrichment sample, but yielded faint, multiple bands from the environmental samples. Nested PCR was conducted using the primers DP142F/DP779R in the first round and DP142F/DP569R in the second round, which generated a bright targeted band. Further phylogenetic analysis showed that these targeted bands were ANME-2d-related sequences. Real-time PCR showed that the copies of the 16s ribosomal RNA gene of ANME-2d in these samples ranged from 3.72 × 10(4) to 2.30 × 10(5) copies ?g(-1) DNA, indicating that the percentage of ANME-2d was greatest in a polluted river sample and least in a rice paddy sample. These results demonstrate that the newly developed real-time PCR primers could sufficiently quantify ANME-2d and that nested PCR with an appropriate combination of the new primers could successfully detect ANME-2d in environmental samples; the latter finding suggests that ANME-2d may spread in environments. PMID:26300291

  6. New generation enrichment monitoring technology for gas centrifuge enrichment plants

    Energy Technology Data Exchange (ETDEWEB)

    Ianakiev, Kiril D [Los Alamos National Laboratory; Alexandrov, Boian S. [Los Alamos National Laboratory; Boyer, Brian D. [Los Alamos National Laboratory; Hill, Thomas R. [Los Alamos National Laboratory; Macarthur, Duncan W. [Los Alamos National Laboratory; Marks, Thomas [Los Alamos National Laboratory; Moss, Calvin E. [Los Alamos National Laboratory; Sheppard, Gregory A. [Los Alamos National Laboratory; Swinhoe, Martyn T. [Los Alamos National Laboratory

    2008-06-13

    The continuous enrichment monitor, developed and fielded in the 1990s by the International Atomic Energy Agency, provided a go-no-go capability to distinguish between UF{sub 6} containing low enriched (approximately 4% {sup 235}U) and highly enriched (above 20% {sup 235}U) uranium. This instrument used the 22-keV line from a {sup 109}Cd source as a transmission source to achieve a high sensitivity to the UF{sub 6} gas absorption. The 1.27-yr half-life required that the source be periodically replaced and the instrument recalibrated. The instrument's functionality and accuracy were limited by the fact that measured gas density and gas pressure were treated as confidential facility information. The modern safeguarding of a gas centrifuge enrichment plant producing low-enriched UF{sub 6} product aims toward a more quantitative flow and enrichment monitoring concept that sets new standards for accuracy stability, and confidence. An instrument must be accurate enough to detect the diversion of a significant quantity of material, have virtually zero false alarms, and protect the operator's proprietary process information. We discuss a new concept for advanced gas enrichment assay measurement technology. This design concept eliminates the need for the periodic replacement of a radioactive source as well as the need for maintenance by experts. Some initial experimental results will be presented.

  7. Earthquake forecast enrichment scores

    Directory of Open Access Journals (Sweden)

    Christine Smyth

    2012-03-01

    Full Text Available The Collaboratory for the Study of Earthquake Predictability (CSEP is a global project aimed at testing earthquake forecast models in a fair environment. Various metrics are currently used to evaluate the submitted forecasts. However, the CSEP still lacks easily understandable metrics with which to rank the universal performance of the forecast models. In this research, we modify a well-known and respected metric from another statistical field, bioinformatics, to make it suitable for evaluating earthquake forecasts, such as those submitted to the CSEP initiative. The metric, originally called a gene-set enrichment score, is based on a Kolmogorov-Smirnov statistic. Our modified metric assesses if, over a certain time period, the forecast values at locations where earthquakes have occurred are significantly increased compared to the values for all locations where earthquakes did not occur. Permutation testing allows for a significance value to be placed upon the score. Unlike the metrics currently employed by the CSEP, the score places no assumption on the distribution of earthquake occurrence nor requires an arbitrary reference forecast. In this research, we apply the modified metric to simulated data and real forecast data to show it is a powerful and robust technique, capable of ranking competing earthquake forecasts.

  8. Energetic optimization of algal lipid production in bubble columns: Part II: Evaluation of CO2 enrichment

    International Nuclear Information System (INIS)

    This study evaluated growth and lipid productivity of Nannochloropsis salina under sparging with carbon dioxide-enriched air. Carbon dioxide enrichments ranging from 0.5 to 9.5% and gas-to-culture volume ratios ranging from 0.02 to 1.0 min?1 were tested in 900 mL bubble column batch reactors. An energy-based approach is proposed to optimize CO2 enrichment. Cultures sparged with CO2-enrichments of 0.5–4% grew at nearly double the rate of those sparged with ambient air, accumulating 64% or more lipids. Based on energy efficiency, CO2-enrichment of 0.5% was found to be optimal while CO2-enrichments of 6.5% and greater were observed to cause inhibition. At this optimal CO2-enrichment of 0.5%, no significant changes were noted in the lipid content over the range of gas-to-culture volume ratios tested. These studies indicated that optimal energy recovery from N. salina can be achieved with CO2-enrichment of 0.5% sparged at a gas-to-culture volume ratio 0.18 min?1. Under this optimal condition, biomass growth rate was 0.161 g L?1 d?1, and the lipid content was 67.8%, yielding total lipid production of 0.771 g L?1 over 10 days at a net energy yield of 25 W m?3. -- Highlights: ? Evaluated algal productivity under sparging with CO2-enriched air. ? Proposed net energy to optimize algal productivity. ? Optimized CO2-enrichment and gas flow to maximize net energy. ? Net energy of 25 W/m3 found under optimal conditions.

  9. Hydrogen-enriched fuels

    Energy Technology Data Exchange (ETDEWEB)

    Roser, R. [NRG Technologies, Inc., Reno, NV (United States)

    1998-08-01

    NRG Technologies, Inc. is attempting to develop hardware and infrastructure that will allow mixtures of hydrogen and conventional fuels to become viable alternatives to conventional fuels alone. This commercialization can be successful if the authors are able to achieve exhaust emission levels of less than 0.03 g/kw-hr NOx and CO; and 0.15 g/kw-hr NMHC at full engine power without the use of exhaust catalysts. The major barriers to achieving these goals are that the lean burn regimes required to meet exhaust emissions goals reduce engine output substantially and tend to exhibit higher-than-normal total hydrocarbon emissions. Also, hydrogen addition to conventional fuels increases fuel cost, and reduces both vehicle range and engine output power. Maintaining low emissions during transient driving cycles has not been demonstrated. A three year test plan has been developed to perform the investigations into the issues described above. During this initial year of funding research has progressed in the following areas: (a) a cost effective single-cylinder research platform was constructed; (b) exhaust gas speciation was performed to characterize the nature of hydrocarbon emissions from hydrogen-enriched natural gas fuels; (c) three H{sub 2}/CH{sub 4} fuel compositions were analyzed using spark timing and equivalence ratio sweeping procedures and finally; (d) a full size pick-up truck platform was converted to run on HCNG fuels. The testing performed in year one of the three year plan represents a baseline from which to assess options for overcoming the stated barriers to success.

  10. Poster 1. Enriched boron products

    International Nuclear Information System (INIS)

    Eagle-Picher can produce large quantities of isotopically enriched boron up to 99 at % boron 10. Two products are of particular interest for the water chemistry in nuclear reactors. Enriched sodium pentaborate can be stored in the standby liquid control tank of the boiling water reactors. It allows the operator to employ more active fuels and still have sufficient shut down capabilities. Enriched boric acid can be used as a chemical shim in the primary cooling system of pressurized water reactors. It provides the benefits associated with high pH without sacrificing the boron 10 content or increasing the lithium content. (author)

  11. High enrichment to low enrichment core's conversion. Accidents analysis

    International Nuclear Information System (INIS)

    This work analyzes the different accidents that may occur in the reactor's facility after the 20% high-enriched uranium core's conversion. The reactor (of 5 thermal Mw), built in the 50's and 60's, is of the 'swimming pool' type, with light water and fuel elements of the curve plates MTR type, enriched at 93.15 %. This analysis includes: a) accidents by reactivity insertion; b) accidents by coolant loss; c) analysis by flow loss and d) fission products release. (Author)

  12. High enrichment to low enrichment core's conversion. Technical securities

    International Nuclear Information System (INIS)

    This work presents the fulfillment of the technical securities subscribed by INVAP S.E. for the conversion of a high enriched uranium core. The reactor (of 5 thermal Mw), built in the 50's and 60's, is of the 'swimming pool' type, with light water and fuel elements of the curve plates MTR type, enriched at 93.15 %. These are neutronic and thermohydraulic securities. (Author)

  13. Enriching rotifers with "premium" microalgae. Nannochloropsis gaditana.

    Science.gov (United States)

    Ferreira, Martiña; Coutinho, Paula; Seixas, Pedro; Fábregas, Jaime; Otero, Ana

    2009-01-01

    The nutritive quality of Nannochloropsis gaditana cultured semicontinuously with different daily renewal rates was tested as a diet for short-term enrichment of the rotifer Brachionus plicatilis. After 24 h, dramatic differences in the survival, dry weight, and biochemical composition of the rotifers depending on the renewal rate of microalgal cultures were observed. Survival after the feeding period increased with increasing renewal rates. Rotifers fed microalgae from low renewal rate, nutrient-deficient cultures showed low dry weight and organic contents very similar to those of the initial rotifers that were starved for 12 h before the start of the feeding period. On the contrary, rotifers fed nutrient-sufficient microalgal cells underwent up to twofold increases of dry weight and protein, lipid, and carbohydrate contents with regard to rotifers fed nutrient-depleted N. gaditana. Consequently, feed conversion rate decreased in these conditions, indicating a better assimilation of the microalgal biomass obtained at high renewal rates. No single microalgal biochemical parameter among those studied can explain the response of the filter feeder. Similarly to gross composition, EPA and n-3 contents in rotifers fed microalgae from nutrient-sufficient cultures were double than the contents found in rotifers fed nutrient-limited microalgae. In addition, very high positive correlations between the contents of EPA and n-3 in N. gaditana and B. plicatilis were observed. These results demonstrate that selecting the appropriate conditions of semicontinuous culture can strongly enhance the nutritional value of microalgae that is reflected in the growth and biochemical composition of the filter-feeder even in short exposure periods. PMID:19153793

  14. Carbon availability and the distribution of denitrifying organisms influence N2O production in the hyporheic zone

    Science.gov (United States)

    Farrell, T. B.; Quick, A. M.; Reeder, W. J.; Tonina, D.; Benner, S. G.; Feris, K. P.

    2013-12-01

    It has been estimated that 10% of greenhouse gas N2O emissions take place within river networks, with the majority of these processes occurring in the hyporheic zone (HZ). These emissions are the result of microbially-mediated nitrogen transformations (i.e. nitrification and denitrification) and yet the role of microbial distribution and function in this complex system is not well understood. We hypothesized that the concentration and availability of organic carbon influences the production of redox gradients, DIN (via mineralization, nitrification, and loss of DIN via denitrification), and ultimately N2O production in the HZ by controlling the distribution and activity of denitrifying microbial communities. Further, we hypothesized that by linking the distribution of denitrifying microbial communities and their associated functional genes (i.e. the relative abundance of N2O vs. N2 producing genetic elements) to flow dynamics and biogeochemical processes, we can begin to better understand what controls N2O production in hyporheic networks. To address these hypotheses we performed a series of column experiments designed to determine the influence of carbon concentration on redox gradient development and N2O flux along a one-dimensional flow path. Intact sediment cores were amended with 0.01%, 0.05%, 0.15%, and 0.5% dry mass riparian vegetation (>90% Populus sp.) to serve as an endogenous particulate organic matter (POM) source. During quasi-steady state conditions dissolved oxygen (DO), NH4+, NO3-, and N2O levels were measured. As predicted, a positive relationship between the level of POM amendment and development of a gradient of oxic and anoxic conditions was observed. There was negligible N2O production within columns inoculated with 0.01% and 0.05% DOC likely because these POC treatments were too low to create anoxic conditions necessary to stimulate denitrification. Maximum N2O flux was observed with the 0.15% POC treatment. Both oxic and anoxic conditions were present in this treatment; conditions suitable for both nitrification and denitrification. However, N2O production was only observed where DO was below detection indicating denitrification as the source of N2O rather than nitrification. Minimal N2O flux was observed in the 0.5% POC treatment. This column was mostly anoxic, likely not supporting nitrification, and thereby limiting denitrification potential. During denitrification, expression of nitrous oxide reductase can enzymatically mediate the reduction of N2O to N2 and is encoded for by the nosZ gene. On-going work includes quantifying the distribution of the nosZ gene within each treatment to determine if the relative abundance of this genetic element correlates with N2O production or if production is primarily controlled by carbon availability and redox conditions.

  15. Abundance of narG, nirS, nirK, and nosZ Genes of Denitrifying Bacteria during Primary Successions of a Glacier Foreland

    Science.gov (United States)

    Kandeler, Ellen; Deiglmayr, Kathrin; Tscherko, Dagmar; Bru, David; Philippot, Laurent

    2006-01-01

    Quantitative PCR of denitrification genes encoding the nitrate, nitrite, and nitrous oxide reductases was used to study denitrifiers across a glacier foreland. Environmental samples collected at different distances from a receding glacier contained amounts of 16S rRNA target molecules ranging from 4.9 × 105 to 8.9 × 105 copies per nanogram of DNA but smaller amounts of narG, nirK, and nosZ target molecules. Thus, numbers of narG, nirK, nirS, and nosZ copies per nanogram of DNA ranged from 2.1 × 103 to 2.6 × 104, 7.4 × 102 to 1.4 × 103, 2.5 × 102 to 6.4 × 103, and 1.2 × 103 to 5.5 × 103, respectively. The densities of 16S rRNA genes per gram of soil increased with progressing soil development. The densities as well as relative abundances of different denitrification genes provide evidence that different denitrifier communities develop under primary succession: higher percentages of narG and nirS versus 16S rRNA genes were observed in the early stage of primary succession, while the percentages of nirK and nosZ genes showed no significant increase or decrease with soil age. Statistical analyses revealed that the amount of organic substances was the most important factor in the abundance of eubacteria as well as of nirK and nosZ communities, and copy numbers of these two genes were the most important drivers changing the denitrifying community along the chronosequence. This study yields an initial insight into the ecology of bacteria carrying genes for the denitrification pathway in a newly developing alpine environment. PMID:16957216

  16. Evaluation of droplet digital PCR for characterizing plasmid reference material used for quantifying ammonia oxidizers and denitrifiers.

    Science.gov (United States)

    Dong, Lianhua; Meng, Ying; Wang, Jing; Liu, Yingying

    2014-02-01

    DNA reference materials of certified value have a critical function in many analytical processes of DNA measurement. Quantification of amoA genes in ammonia oxidizing bacteria (AOB) and archaea (AOA), and of nirS and nosZ genes in the denitrifiers is very important for determining their distribution and abundance in the natural environment. A plasmid reference material containing nirS, nosZ, amoA-AOB, and amoA-AOA is developed to provide a DNA standard with copy number concentration for ensuring comparability and reliability of quantification of these genes. Droplet digital PCR (ddPCR) was evaluated for characterization of the plasmid reference material. The result revealed that restriction endonuclease digestion of plasmids can improve amplification efficiency and minimize the measurement bias of ddPCR. Compared with the conformation of the plasmid, the size of the DNA fragment containing the target sequence and the location of the restriction site relative to the target sequence are not significant factors affecting plasmid quantification by ddPCR. Liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) was used to provide independent data for quantifying the plasmid reference material. The copy number concentration of the digested plasmid determined by ddPCR agreed well with that determined by LC-IDMS, improving both the accuracy and reliability of the plasmid reference material. The reference value, with its expanded uncertainty (k?=?2), of the plasmid reference material was determined to be (5.19?±?0.41)?×?10(9) copies ?L(-1) by averaging the results of two independent measurements. Consideration of the factors revealed in this study can improve the reliability and accuracy of ddPCR; thus, this method has the potential to accurately quantify DNA reference materials. PMID:24493332

  17. Do freshwater macrophytes influence the community structure of ammonia-oxidizing and denitrifying bacteria in the rhizospere?

    DEFF Research Database (Denmark)

    Herrmann, Martina; Schramm, Andreas

    2006-01-01

    DO FRESHWATER MACROPHYTES INFLUENCE THE COMMUNITY STRUCTURE OF AMMONIA-OXIDIZING AND DENITRIFYING BACTERIA IN THE RHIZOSPHERE? M. Herrmann, A. Schramm Department of Biological Sciences, Microbiology, University of Aarhus, Aarhus, Denmark Aquatic macrophytes such as Littorella uniflora and Lobelia dortmanna have been shown to release oxygen from their roots and to stimulate nitrification and coupled nitrification-denitrification in the rhizosphere. Together with the excretion of root exudates, this effect leads to strongly modified microenvironments at the root surface and in the rhizosphere compared to unvegetated sediment, especially with respect to the availability of oxygen, organic carbon, and inorganic nitrogen. We hypothesize that macrophyte species create specific niches for ammonia oxidizing and nitrate-reducing bacteria in their rhizosphere, leading to plant-dependant differences in abundance, activity and composition of these microbial communities between root surface (rhizoplane), rhizosphere and unvegetated sediment. Comparative investigations are carried out focussing on the macrophyte species Littorella uniflora, Juncus bulbosus and Myriophyllum spicatum. Microsensor measurements confirmed the photosynthesis-dependant, species-specific release of oxygen into the rhizosphere; batch incubations indicated a higher nitrification potential in the rhizosphere of Littorella uniflora compared to unvegetated sediment, and will be complemented with the determination of rates of coupled nitrification-denitrification using the 15N isotope pairing technique. Ammonia-oxidizing and nitrate-reducing populations are analyzed based on the ammonia monooxygenase gene (amoA) and the nitrate reductase gene (narG) as functional markers. Preliminary data indicate that there in fact exist differences in the community composition of ammonia oxidizing bacteria between the root surface, the rhizosphere and unvegetated sediment and between plant species, however, differences in the community composition among sampling sites also suggest a strong impact of the chemical properties of the sediment.

  18. Effect of land use on the density of nitrifying and denitrifying bacteria in the Colombian Coffee Region

    Directory of Open Access Journals (Sweden)

    Vallejo Quintero Victoria Eugenia

    2011-12-01

    Full Text Available

    Soil microbial communities involved in the cycling of nitrogen (N are essential to maintaining and improving soil fertility, productivity and functionality of natural and agricultural ecosystems. However, some compounds generated during the metabolic processes performed by nitrifying (NB and denitrifying (DB bacteria are associated with the production of greenhouse gases, groundwater pollution and acidification. Therefore, the study of these bacteria is essential for economic and environmental sustainability. This study evaluated the effect of different land uses in two river basins (La Vieja and Otun on NB and DB densities. Two sampling events (SE were conducted by selecting the most representative land uses. Physicochemical (T °, pH, moisture and nitrate and microbiological properties (NB and DB densities were evaluated. In both SEs, significantly higher densities of NB and DB were observed in the land uses: pasture, guadua (DB only and unshaded coffee (La Vieja and onion (Otun. These land uses, excluding guadua, are dependent on nitrogen fertilizers, which together with the activities of grazing livestock on pastures may lead to greater availability of substrates for the NB. The use of agricultural machinery and overgrazing in pasture and onion uses generate compacted soil and other physical disturbances, encouraging the growth of DB. Forests had the lowest densities of NB and DB possibly due to a reduced availability of N and the releasing of allelopathic compounds from certain plants. Finally, the densities of ammonium-oxidizing bacteria had the greatest differences between the land uses evaluated, demonstrating its high sensitivity to agricultural management practices and livestock. We suggest that changes in the abundance of this community could serve as a relevant and cost-effective bioindicator for soil monitoring.

  19. Draft genome sequence of the denitrifying strain Kiloniella sp. P1-1 isolated from the gut microflora of Pacific white shrimp, Litopenaeus vannamei.

    Science.gov (United States)

    Wang, Liping; Li, Xiaoyi; Shao, Zongze

    2015-12-01

    A denitrifying bacterium, Kiloniella sp. P1-1, was isolated from the intestinal tract contents of Pacific white shrimp (Litopenaeus vannamei) from the Taiwan Strait, China. Here we report the draft genome sequence of Kiloniella sp. P1-1, which comprised 4,312,146 bp in 85 contigs with a G+C content of 46.09%. Related genes involved in the denitrification process could be identified in this genome. The genome sequence of Kiloniella sp. P1-1 may provide insights into the mechanism of denitrification. PMID:26303669

  20. Purification and characterization of benzoate-coenzyme A ligase and 2-aminobenzoate-coenzyme A ligases from a denitrifying Pseudomonas sp.

    OpenAIRE

    Altenschmidt, U; Oswald, B; G. Fuchs

    1991-01-01

    The enzymes catalyzing the formation of coenzyme A (CoA) thioesters of benzoate and 2-aminobenzoate were studied in a denitrifying Pseudomonas sp. anaerobically grown with these aromatic acids and nitrate as sole carbon and energy sources. Three different rather specific aromatic acyl-CoA ligases, E1, E2, and E3, were found which catalyze the formation of CoA thioesters of benzoate, fluorobenzoates, and 2-aminobenzoate. ATP is cleaved into AMP and pyrophosphate. The enzymes were purified, the...

  1. Extraosseus enrichments in bone scintigraphy

    International Nuclear Information System (INIS)

    Extraosseus enrichments are common findings in bone scintigraphy. Main causes are artifacts by skin or cloth contamination, paravenous and subcutaneous injection. Physical examination, removal of cloths, skin cleaning or further images in differing projections lead to the correct diagnosis artefact or extraosseous enrichments. Further on, extraosseous enrichments are seen in physiological variants. In different diseases extraosseous enrichments are common, especially in urinary tract, liver and extremities. Further diagnostics, e.g. conventional radiologic procedures, sonography and CT scans, have to be performed. In individual cases side results in bone scintigraphy lead to formerly unknown diagnosis, further diagnostic procedure is influenced decisively. Own cases show for example a cerebral apoplectic insult, formerly unknown liver metastasis or metastasis in extraosseous Ewings's sarcoma. (orig.)

  2. Uranium enrichment by displacement chromatography

    International Nuclear Information System (INIS)

    Natural Uranium contains 0.72% of fissile isotope 235U. Need for 235U enriched uranium for light water moderated reactors and other uses are well known. Uranium enrichment is a highly complex and tedious process owing to extremely small separation factor. Several processes have been tried; however, gaseous diffusion and centrifugation techniques based on mass dependent isotope effect are being exploited for producing enriched uranium. In the recent past, Isotope fractionation based on mass independent isotope effect such as LASER technique, ion exchange displacement chromatography etc. have drawn the attention of separation scientist and efforts are being made for development and industrial deployment of these technologies. Indian Nuclear Power Programme is based on use of natural uranium (PHWRs) and slightly enriched uranium (BWRs, PWRs) with emphasis on use of vast resources of thorium. Spent fuel from PHWRs, which is depleted in 235U (0.2 to 0.3%), appears to be a promising source of slightly enriched uranium (1 to 3% 235U). Harnessing this source for 235U enrichment would augment fuel supply for PHWR and light water reactors. Ion exchange displacement chromatography is a proliferation resistant novel technique for 235U enrichment. It is based on nuclear field shift - an isotope shift in orbital electrons resulting from the isotopic difference in nuclear size and shape. Due to this effect lighter isotope (235U) exhibits a stronger tendency for a higher valence i.e. UO22+ as compared to heavier isotope (238U). Preliminary laboratory study is being carried out at HWP, Manuguru for exploring feasibility of using ion exchange displacement chromatography for enriching 235U using 4-vinyl pyridine based anion exchange resin

  3. Bioaugmentation of nitrate-dependent anaerobic ferrous oxidation by heterotrophic denitrifying sludge addition: A promising way for promotion of chemoautotrophic denitrification.

    Science.gov (United States)

    Wang, Ru; Zheng, Ping; Zhang, Meng; Zhao, He-Ping; Ji, Jun-Yuan; Zhou, Xiao-Xin; Li, Wei

    2015-12-01

    Nitrate-dependent anaerobic ferrous oxidation (NAFO) is a new and valuable bio-process for the treatment of wastewaters with low C/N ratio, and the NAFO process is in state of the art. The heterotrophic denitrifying sludge (HDS), possessing NAFO activity, was used as bioaugmentation to enhance NAFO efficiency. At a dosage of 6% (V/V), the removal of nitrate and ferrous was 2.4 times and 2.3 times of as primary, and the volumetric removal rate (VRR) of nitrate and ferrous was 2.4 times and 2.2 times of as primary. Tracing experiments of HDS indicated that the bioaugmentation on NAFO reactor was resulted from the NAFO activity by HDS itself. The predominant bacteria in HDS were identified as Thauera (52.5%) and Hyphomicrobium (20.0%) which were typical denitrifying bacteria and had potential ability to oxidize ferrous. In conclusion, HDS could serve as bioaugmentation or a new seeding sludge for operating high-efficiency NAFO reactors. PMID:26348287

  4. Two-step nitrification in a pure moving bed biofilm reactor-membrane bioreactor for wastewater treatment: nitrifying and denitrifying microbial populations and kinetic modeling.

    Science.gov (United States)

    Leyva-Díaz, J C; González-Martínez, A; Muñío, M M; Poyatos, J M

    2015-12-01

    The moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) is a novel solution to conventional activated sludge processes and membrane bioreactors. In this study, a pure MBBR-MBR was studied. The pure MBBR-MBR mainly had attached biomass. The bioreactor operated with a hydraulic retention time (HRT) of 9.5 h. The kinetic parameters for heterotrophic and autotrophic biomasses, mainly nitrite-oxidizing bacteria (NOB), were evaluated. The analysis of the bacterial community structure of the ammonium-oxidizing bacteria (AOB), NOB, and denitrifying bacteria (DeNB) from the pure MBBR-MBR was carried out by means of pyrosequencing to detect and quantify the contribution of the nitrifying and denitrifying bacteria in the total bacterial community. The relative abundance of AOB, NOB, and DeNB were 5, 1, and 3 %, respectively, in the mixed liquor suspended solids (MLSS), and these percentages were 18, 5, and 2 %, respectively, in the biofilm density (BD) attached to carriers. The pure MBBR-MBR had a high efficiency of total nitrogen (TN) removal of 71.81 ± 16.04 %, which could reside in the different bacterial assemblages in the fixed biofilm on the carriers. In this regard, the kinetic parameters for autotrophic biomass had values of Y A  = 2.3465 mg O2 mg N(-1), ? m, A = 0.7169 h(-1), and K NH = 2.0748 mg N L(-1). PMID:26264139

  5. A Systematic Approach to Marital Enrichment.

    Science.gov (United States)

    Dinkmeyer, Don; Carlson, Jon

    1986-01-01

    Presents a systematic approach to enriching marital relationships. The history and current status of marital enrichment is reviewed. An Adlerian approach to marital enrichment is described. Applications of the program in enrichment groups, marriage therapy and couple groups are included. (Author)

  6. Selective enrichment of a methanol-utilizing consortium using pulp & paper mill waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Gregory R. Mockos; William A. Smith; Frank J. Loge; David N. Thompson

    2007-04-01

    Efficient utilization of carbon inputs is critical to the economic viability of the current forest products sector. Input carbon losses occur in various locations within a pulp mill, including losses as volatile organics and wastewater . Opportunities exist to capture this carbon in the form of value-added products such as biodegradable polymers. Waste activated sludge from a pulp mill wastewater facility was enriched for 80 days for a methanol-utilizing consortium with the goal of using this consortium to produce biopolymers from methanol-rich pulp mill waste streams. Five enrichment conditions were utilized: three high-methanol streams from the kraft mill foul condensate system, one methanol-amended stream from the mill wastewater plant, and one methanol-only enrichment. Enrichment reactors were operated aerobically in sequencing batch mode at neutral pH and 25°C with a hydraulic residence time and a solids retention time of four days. Non-enriched waste activated sludge did not consume methanol or reduce chemical oxygen demand. With enrichment, however, the chemical oxygen demand reduction over 24 hour feed/decant cycles ranged from 79 to 89 %, and methanol concentrations dropped below method detection limits. Neither the non-enriched waste activated sludge nor any of the enrichment cultures accumulated polyhydroxyalkanoates (PHAs) under conditions of nitrogen sufficiency. Similarly, the non-enriched waste activated sludge did not accumulate PHAs under nitrogen limited conditions. By contrast, enriched cultures accumulated PHAs to nearly 14% on a dry weight basis under nitrogen limited conditions. This indicates that selectively-enriched pulp mill waste activated sludge can serve as an inoculum for PHA production from methanol-rich pulp mill effluents.

  7. Uranium enrichment: technology, economics, capacity

    International Nuclear Information System (INIS)

    Large-scale enrichment of uranium has now been carried out for 40 years. While the gaseous diffusion process was the original choice of several countries and continues today to provide the major component of the world production of separative work, the last two decades have witnessed the development of a number of alternative processes for enrichment. These processes, which are being studied and deployed around the world, offer a wide range of technical and economic characteristics which will be useful in assuring adequate capacity to meet projected reactor fuel market needs through the rest of this century at competitive prices. With present uncertainties in future enriched uranium needs, it is apparent that flexibility in the deployment and operation of any enrichment process will be one of the prime considerations for the future. More economical production of separative work not only can have a beneficial impact on reactor fuel costs, but also tends to conserve natural uranium resources. This paper reviews the world scene in the enrichment component of the fuel cycle, including existing or planned commercial-scale facilities and announced R and D efforts on various processes

  8. Identification of the function of extracellular polymeric substances (EPS) in denitrifying phosphorus removal sludge in the presence of copper ion.

    Science.gov (United States)

    Wang, Yayi; Qin, Jian; Zhou, Shuai; Lin, Ximao; Ye, Liu; Song, Chengkang; Yan, Yuan

    2015-04-15

    Industrial wastewater containing heavy metals that enters municipal wastewater treatment plants inevitably has a toxic impact on biological treatment processes. In this study, the impact of Cu(II) (0, 1.5, 2, 2.5, 3 mg/L) on the performance of denitrifying phosphorus removal (DPR) and microbial community structures was investigated. Particularly, the dynamic change in the amount and composition of extracellular polymeric substances (EPS), and the role of EPS in P removal, were assessed using three-dimensional excitation-emission matrix fluorescence spectroscopy combined with parallel factor (PARAFAC) analysis. The results showed that, after long-term adjustment, the P removal efficiency was maintained at 95 ± 2.7% at Cu(II) addition up to 2.5 mg/L, but deteriorated when the Cu(II) addition was 3 mg/L. The EPS content, including proteins and humic substances, increased with increasing Cu(II) additions at concentrations ?2.5 mg/L. This property of EPS was beneficial for protecting phosphate-accumulating organisms (PAOs) against heavy metals, as both proteins and humic substances are strong ligands for Cu(II). Therefore, the PAOs abundance was still relatively high (67 ± 3%) when Cu(II) accumulation in sludge was up to 10 mg/g SS. PARAFAC confirmed that aromatic proteins could be transformed into soluble microbial byproduct-like material when microorganisms were subjected to Cu(II) stress, owing to their strong metal ion complexing capacity. The increase in the percentage of humic-like substances enhanced the detoxification function of the sludge EPS. EPS accounted for approximately 26-47% of P removed by adsorption when Cu(II) additions were between 0 and 2.5 mg/L. The EPS function, including binding toxic heavy metals and P storage, enhanced the operating stability of DPR systems. This study provides us with a better understanding of (1) the tolerance of DPR sludge to copper toxicity and (2) the function of sludge EPS in the presence of heavy metals in biological P removal systems. PMID:25697691

  9. Relationship between N2O Fluxes from an Almond Soil and Denitrifying Bacterial Populations Estimated by Quantitative PCR

    Science.gov (United States)

    Matiasek, M.; Suddick, E. C.; Smart, D. R.; Scow, K. M.

    2008-12-01

    Cultivated soils emit substantial quantities of nitrous oxide (N2O), a greenhouse gas with almost 300 times the radiative forcing potential of CO2. Agriculture-related activities generate from 6 to 35 Tg N2O-N per year, or about 60 to 70% of global production. The microbial processes of nitrification, denitrification and nitrifier denitrification are major biogenic sources of N2O to the atmosphere from soils. Denitrification is considered the major source of N2O especially when soils are wet. The microbial N transformations that produce N2O depend primarily on nitrogen (N) fertilizer, with water content, available carbon and soil temperature being secondary controllers. Despite the fact that microbial processes are responsible for N2O emissions, very little is known about the numbers or types of populations involved. The objective of this study was to relate changes in denitrifying population densities, using quantitative PCR (qPCR) of functional genes, to N2O emissions in a fertilized almond orchard. Quantitative PCR targeted three specific genes involved in denitrification: nirS, nirK and nosZ. Copy numbers of the genes were related back to population densities and the portion of organisms likely to produce nitrous oxide. The study site, a 21.7 acre almond orchard fitted with micro-sprinklers, was fertigated (irrigated and fertilized simultaneously) with 50 lbs/acre sodium nitrate in late March 2008, then irrigated weekly. Immediately after the initial fertigation, fluxes of N2O and CO2, moisture content, inorganic N and denitrification gene copy numbers were measured 6 times over 24 days. Despite the fact that N2O emissions increased following fertigation, there was no consistent increase in any of the targeted genes. The genes nirK and nirS ranged from 0.4-1.4 × 107 and 0.4-1.4 × 108, whereas nosZ ranged from 2-8 × 106 copy numbers per g soil, respectively. Considerable variation, compounded by the small sample sizes used for DNA analysis, made it difficult to discern trends over time. High spatial variability was also observed with one of the field replicates have a substantially higher flux of N2O. This replicate also had the highest water filled pore space (WFPS) and water content, factors that likely favored denitrification. Water saturation of soil air space, optimal at >60% for denitrification to occur, was relatively low in the other field replicates. Thus, the low N2O flux measurements and gene copy numbers agreed in supporting the hypothesis denitrification was relatively low under the environmental conditions of these particular almond soils.

  10. Uranium enrichment in the United States

    International Nuclear Information System (INIS)

    History, improvement programs, status of electrical power availability, demands for uranium enrichment, operating plan for the U. S. enriching facilities, working inventory of enriched uranium, possible factors affecting deviations in the operating plan, status of gaseous diffusion technology, status of U. S. gas centrifuge advances, transfer of enrichment technology, gaseous diffusion--gas centrifuge comparison, new enrichment capacity, U. S. separative work pricing, and investment in nuclear energy are discussed. (LK)

  11. Enrichment of light hydrocarbon mixture

    Science.gov (United States)

    Yang, Dali (Los Alamos, NM); Devlin, David (Santa Fe, NM); Barbero, Robert S. (Santa Cruz, NM); Carrera, Martin E. (Naperville, IL); Colling, Craig W. (Warrenville, IL)

    2011-11-29

    Light hydrocarbon enrichment is accomplished using a vertically oriented distillation column having a plurality of vertically oriented, nonselective micro/mesoporous hollow fibers. Vapor having, for example, both propylene and propane is sent upward through the distillation column in between the hollow fibers. Vapor exits neat the top of the column and is condensed to form a liquid phase that is directed back downward through the lumen of the hollow fibers. As vapor continues to ascend and liquid continues to countercurrently descend, the liquid at the bottom of the column becomes enriched in a higher boiling point, light hydrocarbon (propane, for example) and the vapor at the top becomes enriched in a lower boiling point light hydrocarbon (propylene, for example). The hollow fiber becomes wetted with liquid during the process.

  12. Two-Stage Mineralization of Phenanthrene by Estuarine Enrichment Cultures

    OpenAIRE

    Guerin, William F.; Jones, Galen E.

    1988-01-01

    The polycyclic aromatic hydrocarbon phenanthrene was mineralized in two stages by soil, estuarine water, and sediment microbial populations. At high concentrations, phenanthrene was degraded, with the concomitant production of biomass and accumulation of Folin-Ciocalteau-reactive aromatic intermediates. Subsequent consumption of these intermediates resulted in a secondary increase in biomass. Analysis of intermediates by high-performance liquid chromatography, thin-layer chromatography, and U...

  13. Characterization of an anaerobic thermophilic glycerol-degrading enrichment culture

    OpenAIRE

    Cavaleiro, A.J.; Sousa, D. Z.; Alves, M. M.; A. J. M. Stams

    2015-01-01

    Background: The glycerol market was totally changed by the biodiesel industry, which resulted in the production of an excess of this compound as an industrial by-product. As a consequence, the price of glycerol dropped and a huge interest in alternatives for its valorisation emerged since then. In the field of Biotechnology research, glycerol is an attractive compound for the microbial production of chemical building blocks. Objectives: The aim of this work was to investigate thermophilic...

  14. Mixing Intensity Effects of Attached Growth on Enriched Anammox Cultures

    Directory of Open Access Journals (Sweden)

    Pongsak Noophan

    2015-01-01

    Full Text Available Anaerobic ammonium oxidation (anammox is a promising new technology for the treatment of wastewater with high ammonium and low carbon concentrations. Earlier work suggests that optimal processing would be realized within a sequencing batch reactor (SBR. However, the relatively slow growth of anammox bacteria inhibits the rates of nitrogen removal and biomass yielding. Improved anammox performance has been demonstrated when the bacteria are in granular form or attached to a growth medium. Little has been reported concerning the effect of mixing rate on nitrogen (N removal with attached anammox bacteria. This work subjected anammox bacteria attached to polystyrene sponge in SBR to various intensities of impeller mixing and studied the effect on NH4+ and NO2- removal. Nitrogen processing was virtually the same with velocity gradient values between 13.5 and 222 s-1. More vigorous mixing at 407 and 666 s-1 values significantly inhibited N removal, likely due to detachment of bacteria from the growth medium. Following the poor N removal at the two higher mixing intensities, agitation was reduced to 24.8 s-1 velocity gradient value. Recovery of N removal rates required 2-3 weeks, the slow time attributed to slow reattachment to the growth medium. Denaturing gradient gel electrophoresis (DGGE analysis identified the prominent anammox species in the experimental study as Candidatus Brocadia anammoxidans and Candidatus Kuenenia stuttgartiensis.

  15. Morita theory in enriched context

    OpenAIRE

    Segrt Ratkovic, Kruna

    2012-01-01

    We develop a homotopy theoretical version of classical Morita theory using the notion of a strong monad. It was Anders Kock who proved that a monad T in a monoidal category E is strong if and only if T is enriched in E. We prove that this correspondence between strength and enrichment follows from a 2-isomorphism of 2-categories. Under certain conditions on T, we prove that the category of T-algebras is Quillen equivalent to the category of modules over the endomorphism monoid of the T-algebr...

  16. Business History : A Cultural and Narrative Approach

    DEFF Research Database (Denmark)

    Hansen, Per H.

    2012-01-01

    This article argues that a cultural and narrative perspective can enrich the business history field, encourage new and different questions and answers, and provide new ways of thinking about methods and empirical material. It discusses what culture is and how it relates to narratives. Taking a cultural and narrative approach may affect questions, sources, and methodologies, as well as the status of our results. Finally, a narrative approach may contribute to our historical understanding of entrepreneurship and globalization.

  17. Comparison of chalcopyrite bioleaching after different microbial enrichment in shake flasks.

    Science.gov (United States)

    Xia, Lexian; Uribe, Paulina; Liu, Xinxing; Yu, Chu; Chai, Liyuan; Liu, Jianshe; Qiu, Wenqin; Qiu, Guanzhou

    2013-02-01

    The bioleachings of chalcopyrite ore were compared after inoculating different cultures enriched from the original acid mine drainage sample. The results showed that the higher bioleaching performance was achieved for inoculation with the enrichment D (0.5 % S, 2 % iron and 1 % chalcopyrite) compared to other enrichment systems. The generated ferric precipitation during bioleaching had a key influence on the final copper extraction. After enrichment, higher ratio of iron-oxidizer and higher ratio of sulfur-oxidizer existed in enrichment B and C, respectively. These caused the different bioleaching behaviours from other systems. Maintaining a suitable equilibrium between iron- and sulfur-oxidizers is significant to decrease ferric precipitation or postpone its formation, finally prolong efficient bioleaching period and improve copper extraction. PMID:23054700

  18. Enrichment and characterization of sulfate reducing, naphthalene degrading microorganisms

    Science.gov (United States)

    Steffen, Kümmel; Florian-Alexander, Herbst; Márcia, Duarte; Dietmar, Pieper; Jana, Seifert; Bergen Martin, von; Hans-Hermann, Richnow; Carsten, Vogt

    2014-05-01

    Polycyclic aromatic hydrocarbons (PAH) are pollutants of great concern due to their potential toxicity, mutagenicity and carcinogenicity. PAH are widely distributed in the environment by accidental discharges during the transport, use and disposal of petroleum products, and during forest and grass fires. Caused by their hydrophobic nature, PAH basically accumulate in sediments from where they are slowly released into the groundwater. Although generally limited by the low water solubility of PAH, microbial degradation is one of the major mechanisms leading to the complete clean-up of PAH-contaminated sites. Whereas organisms and biochemical pathways responsible for the aerobic breakdown of PAH are well known, anaerobic PAH biodegradation is less understood; only a few anaerobic PAH degrading cultures have been described. We studied the anaerobic PAH degradation in a microcosm approach to enrich anaerobic PAH degraders. Anoxic groundwater and sediment samples were used as inoculum. Groundwater samples were purchased from the erstwhile gas works facility and a former wood impregnation site. In contrast, sources of sediment samples were a former coal refining area and an old fuel depot. Samples were incubated in anoxic mineral salt medium with naphthalene as sole carbon source and sulfate as terminal electron acceptor. Grown cultures were characterized by feeding with 13C-labeled naphthalene, 16S rRNA gene sequencing using an Illumina® approach, and functional proteome analyses. Finally, six enrichment cultures able to degrade naphthalene under anoxic conditions were established. First results point to a dominance of identified sequences affiliated to the freshwater sulfate-reducing strain N47, which is a known anaerobic naphthalene degrader, in four out of the six enrichments. In those enrichments, peptides related to the pathway of anoxic naphthalene degradation in N47 were abundant. Overall the data underlines the importance of Desulfobacteria for natural attenuation of environmental contaminants. Understanding of diversity and physiology of anaerobic PAH degradation will contribute to remediation efforts of low-oxygen environments such as aquifers or river sediments.

  19. Environmental Development Plan: uranium enrichment

    International Nuclear Information System (INIS)

    This Environmental Development Plan identifies and examines the environmental, health, safety, and socioeconomic concerns and corresponding requirements associated with the DOE research, development, demonstration, and operation of the Uranium Enrichment program, including the gaseous diffusion process, the centrifuge process, centrifuge rotor fabrication, and related research and development activities

  20. Enriched Fell Bundles and Spaceoids

    CERN Document Server

    Bertozzini, Paolo; Lewkeeratiyutkul, Wicharn

    2011-01-01

    We propose a definition of involutive categorical bundle (Fell bundle) enriched in an involutive monoidal category and we argue that such a structure is a possible suitable environment for the formalization of different equivalent versions of spectral data for commutative C*-categories.

  1. Nitrite survival and nitrous oxide production of denitrifying phosphorus removal sludges in long-term nitrite/nitrate-fed sequencing batch reactors.

    Science.gov (United States)

    Wang, Yayi; Zhou, Shuai; Ye, Liu; Wang, Hong; Stephenson, Tom; Jiang, Xuxin

    2014-12-15

    Nitrite-based phosphorus (P) removal could be useful for innovative biological P removal systems where energy and carbon savings are a priority. However, using nitrite for denitrification may cause nitrous oxide (N2O) accumulation and emissions. A denitrifying nitrite-fed P removal system [Formula: see text] was successfully set up in a sequencing batch reactor (SBR) and was run for 210 days. The maximum pulse addition of nitrite to [Formula: see text] was 11 mg NO2(-)-N/L in the bulk, and a total of 34 mg NO2(-)-N/L of nitrite was added over three additions. Fluorescent in situ hybridization results indicated that the P-accumulating organisms (PAOs) abundance was 75 ± 1.1% in [Formula: see text] , approximately 13.6% higher than that in a parallel P removal SBR using nitrate [Formula: see text] . Type II Accumulibacter (PAOII) (unable to use nitrate as an electron acceptor) was the main PAOs species in [Formula: see text] , contributing 72% to total PAOs. Compared with [Formula: see text] , [Formula: see text] biomass had enhanced nitrite/free nitrous acid (FNA) endurance, as demonstrated by its higher nitrite denitrification and P uptake rates. N2O accumulated temporarily in [Formula: see text] after each pulse of nitrite. Peak N2O concentrations in the bulk for [Formula: see text] were generally 6-11 times higher than that in [Formula: see text] ; these accumulations were rapidly denitrified to nitrogen gases. N2O concentration increased rapidly in nitrate-cultivated biomass when 5 or 10 mg NO2(-)-N/L per pulse was added. Whereas, N2O accumulation did not occur in nitrite-cultivated biomass until up to 30 mg NO2(-)-N/L per pulse was added. Long-term acclimation to nitrite and pulse addition of nitrite in [Formula: see text] reduced the risk of nitrite accumulation, and mitigated N2O accumulation and emissions from denitrifying P removal by nitrite. PMID:25261626

  2. Dialogismo, lenguas extranjeras e identidad cultural (Dialogism, Foreign Languages, and Cultural Identity).

    Science.gov (United States)

    Zoreda, Margaret Lee

    Foreign Language education will play an important role in the broadening and globalization of higher education for the 21st century. Where else will educators find the tools to "dialog" with--to engage--the "other" as part of the enriching process that accompanies cultural exchange, cultural broadening? This paper sheds light on these issues, and…

  3. Trace elements affect methanogenic activity and diversity in enrichments from subsurface coal bed produced water

    Directory of Open Access Journals (Sweden)

    KlausNüsslein

    2012-05-01

    Full Text Available Microbial methane from coal beds accounts for a significant and growing percentage of natural gas worldwide. Our knowledge of physical and geochemical factors regulating methanogenesis is still in its infancy. We hypothesized that in these closed systems, trace elements (as micronutrients are a limiting factor for methanogenic growth and activity. Trace elements are essential components of enzymes or cofactors of metabolic pathways associated with methanogenesis. This study examined the effects of eight trace elements (iron, nickel, cobalt, molybdenum, zinc, manganese, boron, and copper on methane production, on mcrA transcript levels, and on methanogenic community structure in enrichment cultures obtained from coal bed methane well produced water samples from the Powder River Basin, Wyoming. Methane production was shown to be limited both by a lack of additional trace elements as well as by the addition of an overly concentrated trace element mixture. Addition of trace elements at concentrations optimized for standard media enhanced methane production by 37%. After seven days of incubation, the levels of mcrA transcripts in enrichment cultures with trace element amendment were much higher than in cultures without amendment. Transcript levels of mcrA correlated positively with elevated rates of methane production in supplemented enrichments (R2=0.95. Metabolically-active methanogens, identified by clone sequences of mcrA mRNA retrieved from enrichment cultures, were closely related to Methanobacterium subterraneum and Methanobacterium formicicum. Enrichment cultures were dominated by M. subterraneum and had slightly higher predicted methanogenic richness, but less diversity than enrichment cultures without amendments. These results suggest that varying concentrations of trace elements in produced water from different subsurface coal wells may cause changing levels of coal bed methane production and alter the composition of the active methanogenic community.

  4. Fecal culture

    Science.gov (United States)

    Stool culture; Culture - stool ... stool tests are done in addition to the culture, such as: Gram stain of stool Fecal smear ... RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods . 22nd ed. Philadelphia, PA: Saunders ...

  5. Safeguards Culture

    Energy Technology Data Exchange (ETDEWEB)

    Frazar, Sarah L.; Mladineo, Stephen V.

    2012-07-01

    The concepts of nuclear safety and security culture are well established; however, a common understanding of safeguards culture is not internationally recognized. Supported by the National Nuclear Security Administration, the authors prepared this report, an analysis of the concept of safeguards culture, and gauged its value to the safeguards community. The authors explored distinctions between safeguards culture, safeguards compliance, and safeguards performance, and evaluated synergies and differences between safeguards culture and safety/security culture. The report concludes with suggested next steps.

  6. Absolute enrichment: gene set enrichment analysis for homeostatic systems

    OpenAIRE

    Saxena, Vishal; Orgill, Dennis Paul; Kohane, Isaac Samuel

    2006-01-01

    The Gene Set Enrichment Analysis (GSEA) identifies sets of genes that are differentially regulated in one direction. Many homeostatic systems will include one limb that is upregulated in response to a downregulation of another limb and vice versa. Such patterns are poorly captured by the standard formulation of GSEA. We describe a technique to identify groups of genes (which sometimes can be pathways) that include both up- and down-regulated components. This approach lends insights into the f...

  7. Organizational Culture

    Directory of Open Access Journals (Sweden)

    Adrian HUDREA

    2006-02-01

    Full Text Available Cultural orientations of an organization can be its greatest strength, providing the basis for problem solving, cooperation, and communication. Culture, however, can also inhibit needed changes. Cultural changes typically happen slowly – but without cultural change, many other organizational changes are doomed to fail. The dominant culture of an organization is a major contributor to its success. But, of course, no organizational culture is purely one type or another. And the existence of secondary cultures can provide the basis for change. Therefore, organizations need to understand the cultural environments and values.

  8. Job Enrichment and the Mentally Retarded Worker.

    Science.gov (United States)

    Morris, Jerry L.; And Others

    1981-01-01

    The effect of job enrichment on the production rate of 14 mentally retarded adult workers was evaluated. Job enrichment led to increases in standard rates of production for high IQ Ss and lower rates for low IQ Ss. (Author)

  9. Uranium enrichment (a strategy analysis overview)

    International Nuclear Information System (INIS)

    An analysis of available information on enrichment technology, separative work supply and demand, and SWU cost is presented. Estimates of present and future enrichment costs are provided for use in strategy analyses of alternate nuclear fuel cycles and systems. (auth)

  10. Vegetation, soil and hydrology management influence denitrification activity and the composition of nirK-type denitrifier communities in a newly afforested riparian buffer.

    Science.gov (United States)

    Boz, Bruno; Mizanur Rahman, Md; Bottegal, Mariangela; Basaglia, Marina; Squartini, Andrea; Gumiero, Bruna; Casella, Sergio

    2013-09-25

    Soil microbial community composition and activity could be affected by suitable manipulation of the environment they live in. If correctly applied such an approach could become a very effective way to remediate excess of chemicals. The concentration of nitrogen, especially nitrate deriving from agricultural managements, is generally found to increase in water flow. Therefore, by forcing the water flow through a buffer strip specifically designed and possibly afforested with suitable plant species, may result effective in reducing high nitrogen contents. The management of a riparian buffer may definitely affect the soil microbial activities, including denitrification, as well as the composition of the community. The present study reports on the changes occurred in terms of denitrifying microbial community composition, as compared to that of a neighbouring agricultural area, as a consequence of hydraulic management coupled to the suspension of farming practices and to the development of the woody and herbaceous vegetation. With this aim, denitrification was repeatedly measured and the data obtained were related to those deriving from a specific analysis of bacterial groups involved in denitrification. nirK, encoding for nitrite reductase, an enzyme essential for the conversion of nitrite to nitric oxide and considered the key step in the denitrification process, was chosen as the target gene. The main results obtained indicated that denitrification activity changes in riparian buffer as compared to agricultural soil and it is strongly influenced by carbon availability and soil depth. Although no significant differences on the community composition between superficial (0-15 cm) and medium (40-55 cm) layers were observed, the nirK-type denitrifier community was shown to significantly differ between riparian and agricultural soils in both surface and medium layers. PMID:23567981

  11. Diversity and distribution of amoA-type nitrifying and nirS-type denitrifying microbial communities in the Yangtze River estuary

    Science.gov (United States)

    Zhang, Y.; Xie, X.; Jiao, N.; Hsiao, S. S.-Y.; Kao, S.-J.

    2014-04-01

    Coupled nitrification-denitrification plays a critical role in the removal of excess nitrogen, which is chiefly caused by humans, to mitigate estuary and coastal eutrophication. Despite its obvious importance, limited information about the relationships between nitrifying and denitrifying microbial communities in estuaries, and their controlling factors have been documented. We investigated the nitrifying and denitrifying microbial communities in the estuary of turbid subtropical Yangtze River (YRE), the largest river in Asia, by analyzing the ammonia monooxygenase gene amoA, including archaeal and bacterial amoA, and the dissimilatory nitrite reductase gene nirS using clone libraries and quantitative PCR (qPCR). The diversity indices and rarefaction analysis revealed a quite low diversity for both ?-proteobacterial and archaeal amoA genes, but qPCR data showed significantly higher amoA gene copy numbers for archaea than ?-proteobacteria. Compared with the amoA gene, a significantly higher level of diversity but lower gene copy numbers were found for the nirS gene. Nitrification and denitrification rates based on 15N incubation experiments supported gene abundance data as denitrification rates were below detection limit, suggesting lower denitrification than nitrification potential. In general, the abundances of the amoA and nirS genes were significantly higher in the bottom samples than the surface ones, and in the high-turbidity river mouth, were significantly higher in the particle-associated (> 3 ?m) than the free-living (0.2 ~ 3 ?m) communities. Notably, positive correlations between the amoA and nirS gene abundances suggested potential gene-based coupling between nitrification and denitrification, especially for the particle-associated assemblages. Statistical analysis of correlations between the community structure, gene abundances and environmental variables further revealed that dissolved oxygen and total suspended material might be the key factors controlling community spatial structure and regulating nitrification and denitrification potentials in the YRE ecosystem.

  12. Using metagenomic analyses to estimate the consequences of enrichment bias for pathogen detection

    Directory of Open Access Journals (Sweden)

    Pettengill James B

    2012-07-01

    Full Text Available Abstract Background Enriching environmental samples to increase the probability of detection has been standard practice throughout the history of microbiology. However, by its very nature, the process of enrichment creates a biased sample that may have unintended consequences for surveillance or resolving a pathogenic outbreak. With the advent of next-generation sequencing and metagenomic approaches, the possibility now exists to quantify enrichment bias at an unprecedented taxonomic breadth. Findings We investigated differences in taxonomic profiles of three enriched and unenriched tomato phyllosphere samples taken from three different tomato fields (n?=?18. 16S rRNA gene meteganomes were created for each of the 18 samples using 454/Roche’s pyrosequencing platform, resulting in a total of 165,259 sequences. Significantly different taxonomic profiles and abundances at a number of taxonomic levels were observed between the two treatments. Although as many as 28 putative Salmonella sequences were detected in enriched samples, there was no significant difference in the abundance of Salmonella between enriched and unenriched treatments. Conclusions Our results illustrate that the process of enriching greatly alters the taxonomic profile of an environmental sample beyond that of the target organism. We also found evidence suggesting that enrichment may not increase the probability of detecting a target. In conclusion, our results further emphasize the need to develop metagenomics as a validated culture independent method for pathogen detection.

  13. Enrichment demand boosts SWU prices

    International Nuclear Information System (INIS)

    The enrichment market is picking up significantly on very brisk demand. US utilities, which normally purchase material nine months to a year ahead of time, are already hitting the market to fill their 1996 requirements. In June, two non-US utilities, one European entity and a US utility bought SWUs, the entity in an off-market deal. But that doesn't tell the whole story. Three other US utilities entered the market during the month. Meanwhile, we count 13 more utilities getting ready to hit the market for more than 4 million SWUs. Why the surge in demand? Utilities, uncertain of the role to be played by the new US Enrichment Corp. and seeking to take advantage of low interest rates, are implementing buy and hold strategies. As a result, the upper end of NUKEM's SWU price range inched up to $78. The lower end dipped to $67 based on the European deal

  14. Simulations of Cosmic Chemical Enrichment

    CERN Document Server

    Kobayashi, C; White, S D M; Kobayashi, Chiaki; Springel, Volker; White, Simon D. M.

    2006-01-01

    Using a new numerical model for cosmic chemical evolution, we study the influence of hypernova feedback on the star formation and metal enrichment history of the universe. For assumptions which produce plausible results in idealized collapse models of individual galaxies, our cosmological simulations of the standard Lambda-CDM cosmology show a peak of the cosmic star formation rate at z~4, with ~10% of the baryons turning into stars. We find that the majority of stars in present-day massive galaxies formed in much smaller galaxies at high redshifts, giving them a mean stellar age as old as 10 Gyr, despite their late assembly times. The hypernova feedback drives galactic outflows efficiently in low mass galaxies, and these winds eject heavy elements into the intergalactic medium. The ejected baryon fraction is larger for less massive galaxies, correlates well with stellar metallicity, and amounts to ~20% of all baryons in total. The resulting enrichment history is broadly consistent with the observed abundance...

  15. Introducing Enriched Concrete Syntax Trees

    OpenAIRE

    Raki?, Gordana; Zoran BUDIMAC

    2013-01-01

    In our earlier research an area of consistent and systematic application of software metrics was explored. Strong dependency of applicability of software metrics on input programming language was recognized as one of the main weaknesses in this field. Introducing enriched Concrete Syntax Tree (eCST) for internal and intermediate representation of the source code resulted with step forward over this weakness. In this paper we explain innovation made by introducing eCST and pr...

  16. Enrichment techniques employed in phosphoproteomics.

    Czech Academy of Sciences Publication Activity Database

    Fíla, Jan; Honys, David

    2012-01-01

    Ro?. 43, ?. 3 (2012), s. 1025-1047. ISSN 0939-4451 R&D Projects: GA ?R(CZ) GAP501/11/1462; GA ?R GA522/09/0858; GA ?R GA525/09/0994; GA MŠk OC08011 Institutional research plan: CEZ:AV0Z50380511 Keywords : Phosphoproteomics * Enrichment * IMAC Subject RIV: ED - Physiology Impact factor: 3.914, year: 2012

  17. CNA Laboratory Enrichment By Virtualization

    OpenAIRE

    Adodo, Segun

    2011-01-01

    This study is related to networking and the aim is to enrich the laboratory work aspect of the networking study module as implemented by the school’s information technology department. The existing practice lab structures in the institution’s information technology degree programme rely more on Microsoft windows than other operating systems. As a result, experience in non-window operating systems is low in students. To increase the awareness of the Linux operating system among networking ...

  18. How Did the IGM Become Enriched?

    OpenAIRE

    Aguirre, Anthony; Schaye, Joop

    2006-01-01

    The enrichment of the intergalactic medium with heavy elements is a process that lies at the nexus of poorly-understood aspects of physical cosmology. We review current understanding of the processes that may remove metals from galaxies, the basic predictions of these models, the key observational constraints on enrichment, and how intergalactic enrichment may be used to test cosmological simulations.

  19. Urenco's contribution to the enrichment market

    International Nuclear Information System (INIS)

    The paper deals with the Present status of Urenco Enrichment Plants and Order Book, Urenco's future development, The Western World enrichment supply situation, Urenco's Policy on the reliability of enrichment supplies, and its contribution to a reliable, stable and competitive world enrichment market. Urenco's current plant capacity and forward committed expansion plans up to 1990 and its present position in the western world enrichment market are described. The application of Urenco's centrifuge technology to the enrichment of recycles uranium and the relevance of laser enrichment development to Urenco are discussed. The paper next discusses the structure and main characteristics of the major sectional markets of the western world enrichment market, i.e. particularly in the United States, Western Europe and Asia (Japan, Korea and Taiwan). Urenco's contractual approach regarding the reliability of enrichment supplies is discussed, it is shown that Urenco's development of the centrifuge process to the point of economic maturity, Urenco's establishment of a multi-national commercial enrichment organization, Urenco's achievement in the world enrichment market by a commercial and competitive approach, Urenco's preparedness to negotiate suitable supply arrangements including the establishment of plants in other market areas have vastly contributed to a stabilisation of the world enrichment market. (J.P.N.)

  20. Perspectives on Job Enrichment and Productivity.

    Science.gov (United States)

    Suojanen, Waino W., Ed.; And Others

    The book of reading focuses on the state of job enrichment in the United States today, as well as some of its international implications. Featured in the book are 20 selected working papers analyzing the development and use of job enrichment in various types of organizations, union response to job enrichment, and its outlook for the future. The…

  1. Uranium enrichment and public policy

    International Nuclear Information System (INIS)

    Alternative policies to the present government monopoly of the uranium enrichment process are discussed in this monograph. Alternative policies analyzed are continued government monopoly and operation by the Department of Energy, establishment of a government corporation, and complete relinquishing of government control with the private sector taking the risks of constructing additional capacity. The material is divided into 6 chapters. Chapter 1 describes the fuel cycle and the public policy issues involved. The enrichment process, current capacity, and the operation of the plants by the government are described in Chapter 2. Chapter 3 estimates future demand for electricity in the U.S. and forecasts the demand for nuclear power and for enrichment services. Chapter 4 describes the historical background, including the Nuclear Fuel Assurance Act, opposition to it, and its demise. The basic policy options the government faces with an analysis of the advantages and disadvantages of each are included in Chapter 5. The final chapter summarizes the findings and presents the conclusion that, from an economic efficiency viewpoint, selling the existing plants and turning the industry over to the private sector would be best. An appendix describes some of the issues involved in plutonium recycling

  2. Cascade device for enriching uranium

    International Nuclear Information System (INIS)

    Object: To separate and remove impure gas of light mass from a flow of UF6 gas and increase the UF6 gas in pressure to be fed into stages, thereby enhancing cascade effect. Structure: Raw gas supplied from a raw material supply pipe is introduced into a separator while mixed with waste gas fed from a first stage on the enriching side through a connection pipe and product gas fed from a first stage on the depletion side through another connection pipe. The separator has its function to separate light gas from heavy gas by the action of centrifugal force to increase pressure of the heavy gas. The thus separated light gas is discharged outside the system by means of a vacuum pump through a light gas discharge pipe, a light gas manifold and a cold trap, whereas the heavy gas (feed gas) is sent to the raw material supply stage. The product gas enriched in the raw material supply stage is mixed with waste gas discharged from another stage on the enriching side and flown into next separator. (Kamimura, M.)

  3. Using Salt-Enriched Diets to Reduce Stress in Trout

    Directory of Open Access Journals (Sweden)

    Amanda E. Smith

    2005-01-01

    Full Text Available Chronically stressful conditions in fish culture facilities can lead to outbreaks of disease and reductions in growth and performance. A secondary response to stress in fish is the sudden and significant loss of plasma chloride ions, a condition known as hypochloremia. This loss of plasma chloride has been implicated as a cause of mortality in severely stressed fish. The effect of increased dietary salt on reducing hypochloremia in rainbow trout (Onchorynchus mykiss subjected to a confinement challenge was investigated. Experimental diets included added NaCl or CaCl2. Trout fed salt-enriched diets suffered less hypochloremia in the early hours or confinement. Trout fed a higher level of NaCl had significantly higher recovery plasma chloride levels post-stress. Salt-enriched diets containing moderate levels of NaCl may offer some benefit in recovering trout that have been exposed to stress.

  4. Decoding cultural landscapes: guiding principles for the management of interpretation in cultural world heritage sites

    OpenAIRE

    Kamel, Ehab

    2011-01-01

    Conserving the cultural significance of heritage sites - as the guardians of social unity, place identity, and national pride - plays an essential role in maintaining sustainable social development, as well as preserving the variations identifying cultural groups and enriching the interaction between them. Consequently, and considering the importance of the built environment in communicating, as well as documenting, cultural messages, this research project, started in 2007, develops a set of ...

  5. Culture matters.

    Science.gov (United States)

    Arif, Zeba

    Zebaa Arif reflects on changes during her career as a mental health nurse in relation to cultural care issues: Cultural awareness is becoming embedded in patient care. All aspects of care are influenced by cultural beliefs and should form part of assessment. Leadership is essential in influencing cultural care, as is organisational commitment. PMID:16262169

  6. Learning Culture.

    Science.gov (United States)

    Jones, David

    Adult and continuing education in the arts can and does play a role in the development of cultural identity. Dimensions of culture include ethnicity, location, age, social class, and time. This definition of culture leads to the conclusion that cultures are generally small and are dynamic rather than static. Research shows that individuals in what…

  7. Cultural Heritage Content Re-Use: An Aggregators's Point of View

    Science.gov (United States)

    Gavrilis, D.; Ioannides, M.; Theofanous, E.

    2015-08-01

    This paper introduces a use case of re-using aggregated and enriched metadata for the tourism creative industry. The MORe aggregation and enrichment framework is presented along with an example for enriching cultural heritage objects harvested from a number of Omeka repositories. The enriched content is then published both to the EU Digital Library Europeana (http://www.europeana.eu) and to an Elastic Search component that feeds a portal aimed at providing tourists with interesting information.

  8. Development of enrichment measurement technologies at the Ningyo-Toge uranium enrichment pilot plant

    International Nuclear Information System (INIS)

    The enrichment measurement of UF6 is one of the most important techniques for a gas centrifuge enrichment plant. Developments of enrichment measurements using non-destructive assay technologies have been carried out at the Ningyo-Toge Uranium Enrichment Pilot Plant, PNC. Included in these developments are an enrichment monitor on 30B type cylinders, a neutron monitor, in-line enrichment monitors, and those for pipework and for sample bottles, and the field test of the IAEA gas phase enrichment monitor. The evaluation applications of these monitors, used for both safeguards and process control, are described. (author)

  9. Spatial Culture

    DEFF Research Database (Denmark)

    Reeh, Henrik

    2012-01-01

    Spatial Culture – A Humanities Perspective Abstract of introductory essay by Henrik Reeh Secured by alliances between socio-political development and cultural practices, a new field of humanistic studies in spatial culture has developed since the 1990s. To focus on links between urban culture and modern society is, however, an intellectual practice which has a much longer history. Already in the 1980s, the debate on the modern and the postmodern cited Paris and Los Angeles as spatio-cultural ill...

  10. Environmental enrichment for primates in laboratories

    Science.gov (United States)

    Buchanan-Smith, H. M.

    2010-06-01

    Environmental enrichment is a critical component of Refinement, one of the 3Rs underlying humane experimentation on animals. In this paper I discuss why primates housed in laboratories, which often have constraints of space and study protocols, are a special case for enrichment. I outline a framework for categorising the different types of enrichment, using the marmoset as a case study, and summarise the methods used to determine what animals want/prefer. I briefly review the arguments that enrichment does not negatively affect experimental outcomes. Finally I focus on complexity and novelty, choice and control, the underlying features of enrichment that makes it successful, and how combined with a thorough understanding of natural history we can put effective enrichment into practice in laboratories. Throughout the paper I emphasise the need to evaluate enrichment to ensure it is having the desired effect.

  11. Enrichment and specific quantification of Methanocalculus in anaerobic digestion.

    Science.gov (United States)

    Chen, Si; He, Qiang

    2015-12-01

    Members of the genus Methanocalculus are characterized as hydrogenotrophic methanogens and present in diverse natural and engineered environments. Methanocalculus populations were enriched from anaerobic digesters treating dairy waste using formate as the substrate. Methanocalculus sequences retrieved from the enrichment cultures were subsequently used to develop a Methanocalculus-specific TaqMan qPCR assay to determine the abundance of Methanocalculus populations in the environment, representing the first quantitative tool specifically targeting Methanocalculus. The Methanocalculus-specific primer/probe set was shown to have high coverage with perfect match to >80% of all Methanocalculus 16S rRNA gene sequences in the Ribosomal Database Project (RDP). High specificity of the qPCR assay was also validated by both in silico and experimental analyses. Amplification efficiency of the qPCR assay was determined to be 91.9%, which is satisfactory for quantitative applications. Results from the Methanocalculus-specific qPCR analysis of formate-enriched methanogenic cultures were consistent with those from clone library analysis of the same cultures, validating the accuracy of the qPCR assay. Subsequent field application of the qPCR assay found low relative abundance of Methanocalculus in anaerobic digesters treating dairy waste, accounting for 0.01% of the archaeal populations. The qPCR results were consistent with the lack of detection of Methanocalculus in previous studies of the same anaerobic digesters with clone library analyses, which are less sensitive than qPCR. Thus, the Methanocalculus-specific qPCR assay developed in this study is a highly sensitive tool for the rapid and efficient quantification of Methanocalculus populations in methanogenic environments and understanding of the ecological functions of these methanogens. PMID:26059102

  12. 31 CFR 540.308 - Low Enriched Uranium (LEU).

    Science.gov (United States)

    2010-07-01

    ... 2010-07-01 false Low Enriched Uranium (LEU). 540.308 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

  13. 31 CFR 540.306 - Highly Enriched Uranium (HEU).

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Highly Enriched Uranium (HEU). 540.306 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.306 Highly Enriched Uranium (HEU). The term highly enriched...

  14. Cultural commons and cultural evolution

    OpenAIRE

    Bravo, Giangiacomo

    2010-01-01

    Culture evolves following a process that is akin to biological evolution, although with some significant differences. At the same time culture has often a collective good value for human groups. This paper studies culture in an evolutionary perspective, with a focus on the implications of group definition for the coexistence of different cultures. A model of cultural evolution is presented where agents interacts in an artificial environment. The belonging to a specific memet...

  15. Enrichment of carbon monoxide utilising microorganisms from methanogenic bioreactor sludge

    OpenAIRE

    Pereira, Ana Luísa; A. J. M. Stams; Alves, M. M.; Sousa, D. Z.

    2015-01-01

    Conversion of CO is the rate limiting step during anaerobic conversion of syngas (a gaseous mixture mainly composed of CO, CO2 and H2). In this work we study the microbial diversity in anaerobic sludge submitted to extended contact to syngas in a multi-orifice baffled bioreactor (MOBB). Methane was the main product resulting from syngas conversion in the MOBB. Enrichment cultures started with this sludge produced methane as final product, but also acetate. 16S rRNA gene analysis revealed a pr...

  16. Enrichment planting without soil treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hagner, Mats

    1998-12-31

    Where enrichment planting had been carried out with either of the two species Picea abies and Pinus contorta, the survival of the planted seedlings was at least as good as after planting in a normal clear cut area treated with soil scarification. This was in spite of the fact that the seedlings were placed shallow in the humus layer without any soil treatment. However, they were sheltered from insects by treatment before planting. Where enrichment planting was carried out with Pinus sylvestris the survival in dense forest was poor, but in open forest the survival was good. The growth of planted seedlings was enhanced by traditional clearing and soil treatment. However, this was for Pinus sylvestris not enough to compensate for the loss of time, 1-2 years, caused by arrangement of soil scarification. The growth of seedlings planted under crown cover was directly related to basal area of retained trees. However, the variation in height growth among individual seedlings was very big, which meant that some seedlings grow well also under a fairly dense forest cover. The pioneer species Pinus sylvestris reacted more strongly to basal area of retained trees than did the shade tolerant species Picea abies. Enrichment planting seems to be a necessary tool for preserving volume productivity, at places where fairly intensive harvest of mature trees has been carried out in stands of ordinary forest type in central Sweden. If double seedlings, with one Picea abies and one Pinus sylvestris, are used, the probability for long term establishment is enhanced 13 refs, 20 figs, 4 tabs

  17. DOE enrichment plant hums ahead

    International Nuclear Information System (INIS)

    The Department of Energy's $10-billion gas centrifuge uranium enrichment plant, after three years of construction, is rising on schedule near Piketon, Ohio. A detailed conceptual design, smart management, liberal design fees, hungry contractors and cooperative unions are combining to get the job done. One reason for completing the task is that this will be a far more efficient process - 135 MW will be required to operate the centrifuge plant vs more than 2100 MW to produce the same amount of fuel at the mile-square diffusion plant near Portsmouth, Ohio

  18. Pathogen enrichment device (PED) enables one-step growth, enrichment and separation of pathogen from food matrices for detection using bioanalytical platforms.

    Science.gov (United States)

    Hahm, Byoung-Kwon; Kim, Hyochin; Singh, Atul K; Bhunia, Arun K

    2015-10-01

    The bottleneck for accurate detection of foodborne pathogens is separation of target analytes from complex food matrices. Currently used sample preparation methods are cumbersome, arduous and lengthy; thus, a user-friendly system is desirable. A hand-held sample preparation system designated pathogen enrichment device (PED) was built that contains a growth chamber, filters, and an ion exchange cartridge to deliver bacteria directly onto the detection platforms. Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes were used as model pathogens. Spinach, ground beef, hotdogs, and eggs were used as model foods to evaluate PED performance, and results were compared with traditional bag enrichment method. Bacterial cells were inoculated at 1, 10, and 100CFU/g of the sample and enriched in PED using appropriate pathogen-specific selective enrichment broths. The bacterial cell counts in both PED and stomacher-bag were comparable and the pH in PED-recovered cell suspension was close to neutral whereas the pH of cell suspension in the stomacher-bag was slightly acidic. The bacterial recovery from the PED was 79-100% and was directly detected by lateral-flow immunoassay (LFIA), quantitative PCR (qPCR) and light scattering sensor with sample-to-result time of 8-24h with a detection limit of 1CFU/g. In qPCR, the amplified PCR products appeared in 4-5cycles earlier with PED-enriched cultures compared to the cultures enriched in stomacher-bag. The hand-held PED proved to be a one-step procedure for enrichment and recovery of homogenous particle-free bacterial cells for detection using immunological, molecular or biosensor-based platforms. PMID:26211638

  19. Cultural Neuroscience.

    Science.gov (United States)

    Ames, Daniel L; Fiske, Susan T

    2010-06-01

    Cultural neuroscience issues from the apparently incompatible combination of neuroscience and cultural psychology. A brief literature sampling suggests, instead, several preliminary topics that demonstrate proof of possibilities: cultural differences in both lower-level processes (e.g. perception, number representation) and higher-order processes (e.g. inferring others' emotions, contemplating the self) are beginning to shed new light on both culture and cognition. Candidates for future cultural neuroscience research include cultural variations in the default (resting) network, which may be social; regulation and inhibition of feelings, thoughts, and actions; prejudice and dehumanization; and neural signatures of fundamental warmth and competence judgments. PMID:23874143

  20. Fluxes in PHA-storing microbial communities during enrichment and biopolymer accumulation processes.

    Science.gov (United States)

    Janarthanan, Om Murugan; Laycock, Bronwyn; Montano-Herrera, Liliana; Lu, Yang; Arcos-Hernandez, Monica V; Werker, Alan; Pratt, Steven

    2016-01-25

    The use of mixed microbial cultures for the production of polyhydroxyalkanoates (PHAs) is emerging as a viable technology. In this study, 16S rRNA gene amplicon pyrosequencing was used to analyse fluctuations in populations over a 63-day period within a PHA-storing mixed microbial community enriched on fermented whey permeate. This community was dominated by the genera Flavisolibacter and Zoogloea as well as an unidentified organism belonging to the phylum Bacteroidetes. The population was observed to cycle through an increase in Zoogloea followed by a return to a community composition similar to the initial one (highly enriched in Flavisolibacter). It was found that the PHA accumulation capacity of the community was robust to population flux during enrichment and even PHA accumulation, with final polymer composition dependent on the overall proportion of acetic to propionic acids in the feed. This community adaptation suggests that mixed culture PHA production is a robust process. PMID:26257140

  1. Priming tissue cultured propagules

    International Nuclear Information System (INIS)

    Priming of in vitro propagules refers to the manipulation of the growing environment, prior to and upon transplanting, and is an integral part of tissue culture propagation. Tissue-cultured propagules are produced under controlled environment. Such plantlets have small juvenile leaves with reduced photosynthetic capacity, and malfunctioning stomata. Priming for rooting, shooting, and improved photosynthesis can be achieved with growth regulators and simple adjustment to the growing conditions that affect the post-transplanting performance of the propagules. Vented closures with microbial filters have been used to facilitate gas exchange to reduce ethylene build-up that stunts plant growth, reduces leaf-size, and causes leaf drop in tissue culture containers. Plantlets produced under photoautotrophic culture systems on media with or without sucrose but CO2-enrichment, increased light intensity, good gas exchange and reduced humidity are more vigorous, have larger root- systems, and are less susceptible to microbial contamination. Plants adapted gradually to the ex-vitro environment have improved survival upon transfer to soil. Plants in their natural environment are colonized with many bacteria, fungi, and mycorrhizae. In-vitro or ex-vitro biopriming of micropropagated plants with such organisms can improve plant performance under stress environments, and consequently enhances yield. (author)

  2. Impact of Pre-enrichment media pH on Salmonella detection

    Science.gov (United States)

    In a recent study, the ph of commonly used Salmonella pre-enrichment medias became acidic (pH 4.0 to 5.0) when feed/ingredient were incubated for 24 hrs. Acidic conditions have been reported to injure or kill Salmonella. In this study, non-stressed and stressed cultures of S. typhimurium (ST), S. e...

  3. Use of an Interculturally Enriched Collaboration Script in Computer-Supported Collaborative Learning in Higher Education

    Science.gov (United States)

    Popov, Vitaliy; Biemans, Harm J. A.; Kuznetsov, Andrei N.; Mulder, Martin

    2014-01-01

    In this exploratory study, the authors introduced an interculturally enriched collaboration script (IECS) for working in culturally diverse groups within a computer-supported collaborative learning (CSCL) environment and then assessed student online collaborative behaviour, learning performance and experiences. The question was if and how these…

  4. Virtual Interaction through Video-Web Communication: A Step towards Enriching and Internationalizing Language Learning Programs

    Science.gov (United States)

    Jauregi, Kristi; Banados, Emerita

    2008-01-01

    This paper describes an intercontinental project with the use of interactive tools, both synchronous and asynchronous, which was set up to internationalize academic learning of Spanish language and culture. The objective of this case study was to investigate whether video-web communication tools can contribute to enriching the quality of foreign…

  5. Repellent Culture.

    Science.gov (United States)

    Carroll, Jeffrey

    2001-01-01

    Considers defining "culture," noting how it is difficult to define because those individuals defining it cannot separate themselves from it. Relates these issues to student writing and their writing improvement. Addresses violence in relation to culture. (SG)

  6. Rectal culture

    Science.gov (United States)

    ... The swab is rotated gently, and removed. A smear of the swab is placed in culture media ... you have an infection. This may be from bacterial or parasitic enterocolitis or gonorrhea. Sometimes a culture ...

  7. Gastric culture

    Science.gov (United States)

    Gastric culture is a test to check a child's stomach contents for the bacteria that cause tuberculosis (TB). ... is placed in a special dish called a culture medium and watched for the growth of bacteria.

  8. Throat Culture

    Science.gov (United States)

    ... limited. Home Visit Global Sites Search Help? Throat Culture Share this page: Was this page helpful? Collecting | ... treatment | Getting results | see BLOOD SAMPLE Collecting A culture is a test that is often used to ...

  9. Culturing Protozoa.

    Science.gov (United States)

    Stevenson, Paul

    1980-01-01

    Compares various nutrient media, growth conditions, and stock solutions used in culturing protozoa. A hay infusion in Chalkey's solution maintained at a stable temperature is recommended for producing the most dense and diverse cultures. (WB)

  10. Safety culture

    International Nuclear Information System (INIS)

    Safety culture has become a topic of increasing interest for industry and regulators as issues are raised on safety problems around the world. The keys to safety culture are organizational effectiveness, effective communications, organizational learning, and a culture that encourages the identification and resolution of safety issues. The necessity of a strong safety culture places an onus on all of us to continually question whether the safety measures already in place are sufficient, and are being applied. (author)

  11. Cultural Neuroscience

    OpenAIRE

    Ames, Daniel L.; Fiske, Susan T

    2010-01-01

    Cultural neuroscience issues from the apparently incompatible combination of neuroscience and cultural psychology. A brief literature sampling suggests, instead, several preliminary topics that demonstrate proof of possibilities: cultural differences in both lower-level processes (e.g. perception, number representation) and higher-order processes (e.g. inferring others’ emotions, contemplating the self) are beginning to shed new light on both culture and cognition. Candidates for future cultu...

  12. Stable coexistence of two Caldicellulosiruptor species in a de novo constructed hydrogen-producing co-culture

    OpenAIRE

    Rådström Peter; Zeidan Ahmad A; Van Niel Ed WJ

    2010-01-01

    Abstract Background Mixed culture enrichments have been used frequently for biohydrogen production from different feedstock. In spite of the several advantages offered by those cultures, they suffer poor H2 yield. Constructing defined co-cultures of known H2 producers may offer a better performance than mixed-population enrichments, while overcoming some of the limitations of pure cultures based on synergies among the microorganisms involved. Results The extreme thermophiles Caldicellulosirup...

  13. Evaluación del crecimiento de un cultivo de Daphnia magna alimentado con Saccharomyces cereviseae y un enriquecimiento con avena soya / Growth culture evaluation of Daphnia magna feed with Saccharomyces cereviseae enrichment with oat soy / Avaliação do crescimento de um cultivo de Daphnia magna alimentada con Saccharomyces cereviseae e um meio enrriquecido com aveia soja

    Scientific Electronic Library Online (English)

    Lucía E, Ocampo; Mónica C, Botero; Luis F, Restrepo.

    2010-03-01

    Full Text Available O objetivo do experimento foi avaliar o efeito das gorduras saturadas e insaturadas e seu grau de proteção (protegidas e sem proteção) sob a cinética e a extensão da degradação in vitro da matéria seca (MS) em dietas para ruminantes. Quatro dietas foram formuladas para conter o mesmo nível de energi [...] a (3200 Kcal ED /Kg MS) e proteína (13%PC) a ração total misturada (RTM), de acordo com as necessidades nutricionais de ovelhas em fase de finalização, quatro tipos de gorduras foram feitas com 8% de MS e foram testados tipos de gorduras foram testados: 1) gordura saturada sem proteção (GSSP), 2) gordura saturada protegida (GSP), 3) gordura insaturada sem proteção (GISP) e 4) gordura insaturada protegida (GIP). Para estimar a cinética e a extensão da degradação da MS e cinética da produção de gás, as rações foram avaliadas mediante a técnica in vitro de produção de gás, seguindo os modelos propostos por Orskov e McDonald (1979) y France et al (1993), para isto foi empregado o procedimento PROC NLIN de SAS (2001). Ao mesmo tempo, foi realizado um analise de medidas repetidas no tempo para verificar o efeito dos tratamentos sobre a produção de gás e a degradação da MS no tempo com ajuda do procedimento PROC MIXED do SAS (2001.) Neste experimento verificou-se que a utilização de gorduras insaturadas protegidas não afetou a degradação de MS quando comparadas com as não protegidas. No caso das gorduras saturadas, não houve um claro efeito da proteção sob a degradação e a cinética de fermentação da MS. Abstract in spanish Se realizó el cultivo experimental de cladócero Daphnia magna alimentado con probióticos. Se realizaron 16 ensayos experimentales, en el laboratorio de larvicultura de peces y alimento vivo (Larpeali) de la Facultad de Ciencias Agrarias de la Universidad de Antioquia, bajo condiciones controladas de [...] temperatura ambiente (21 - 25 °C), temperatura del agua (22 - 23 °C) y pH (7.6). Empleando una dieta de Saccharomyces cereviseae y un medio de enriquecimiento con ácidos grasos (n-6) proveniente de harina avena-soya. Las concentraciones de dieta y enriquecimiento fueron de 25 ppm y 12.5 ppm, en arreglo factorial 2x2 (2 niveles de dieta con levadura y 2 niveles dieta con avena de soya), los cultivos de Daphnia por tratamiento se realizaron con cuatro replicas con el fin de determinar su efecto sobre el desempeño de la población. Se alimentaron cada tercer día, durante 15 días, evaluándose el número de organismos al final del período. Se obtuvieron diferencias altamente significativas (p0.05). Se evidenció que la combinación de estos componentes en sus concentraciones más altas potenció el crecimiento de la Daphnia magna, alcanzando un número de microcrustáceos de 826ª Daphnias/L ± 9.57. Se puede concluir que los cladóceros por sus características de crecimiento en cultivo, presentan adaptación favorable a las condiciones de manejo para la producción de biomasa útil como alimento vivo en acuicultura. Abstract in english Experimental cultivate cladocerans Daphnia magna feed with probiotics was realized. At University of Antioquia, Faculty of Agrarian Science, Larviculture, fish and food live Laboratory (Larpeali), under controlled conditions of environmental temperature between (21 - 25 °C), water temperature (22 - [...] 23°C) and pH (7.6), were performed. One diet of Saccharomyces cereviseae was used and one enriched medium of oat-soy flour (fatty acid, n-6) to concentrations of diet and enriched medium were the same, 25 ppm and 12.5 ppm, 2x2 factorial treatment arrangements (2 levels of Saccharomyces cereviseae and 2 levels of oat-soy flour, diets was fed to four replicates of Daphnia culture per treatment in order to determine their effects on the populations cultivated. A 15-days feeding, each third day, trial were conducted, to assess the organisms at final period. The results showed significant high difference (p0.05). The results showed that the combination of their high concentrations of components enhan

  14. Evaluación del crecimiento de un cultivo de Daphnia magna alimentado con Saccharomyces cereviseae y un enriquecimiento con avena soya Avaliação do crescimento de um cultivo de Daphnia magna alimentada con Saccharomyces cereviseae e um meio enrriquecido com aveia soja Growth culture evaluation of Daphnia magna feed with Saccharomyces cereviseae enrichment with oat soy

    Directory of Open Access Journals (Sweden)

    Lucía E Ocampo

    2010-03-01

    Full Text Available Se realizó el cultivo experimental de cladócero Daphnia magna alimentado con probióticos. Se realizaron 16 ensayos experimentales, en el laboratorio de larvicultura de peces y alimento vivo (Larpeali de la Facultad de Ciencias Agrarias de la Universidad de Antioquia, bajo condiciones controladas de temperatura ambiente (21 - 25 °C, temperatura del agua (22 - 23 °C y pH (7.6. Empleando una dieta de Saccharomyces cereviseae y un medio de enriquecimiento con ácidos grasos (n-6 proveniente de harina avena-soya. Las concentraciones de dieta y enriquecimiento fueron de 25 ppm y 12.5 ppm, en arreglo factorial 2x2 (2 niveles de dieta con levadura y 2 niveles dieta con avena de soya, los cultivos de Daphnia por tratamiento se realizaron con cuatro replicas con el fin de determinar su efecto sobre el desempeño de la población. Se alimentaron cada tercer día, durante 15 días, evaluándose el número de organismos al final del período. Se obtuvieron diferencias altamente significativas (p0.05. Se evidenció que la combinación de estos componentes en sus concentraciones más altas potenció el crecimiento de la Daphnia magna, alcanzando un número de microcrustáceos de 826ª Daphnias/L ± 9.57. Se puede concluir que los cladóceros por sus características de crecimiento en cultivo, presentan adaptación favorable a las condiciones de manejo para la producción de biomasa útil como alimento vivo en acuicultura.O objetivo do experimento foi avaliar o efeito das gorduras saturadas e insaturadas e seu grau de proteção (protegidas e sem proteção sob a cinética e a extensão da degradação in vitro da matéria seca (MS em dietas para ruminantes. Quatro dietas foram formuladas para conter o mesmo nível de energia (3200 Kcal ED /Kg MS e proteína (13%PC a ração total misturada (RTM, de acordo com as necessidades nutricionais de ovelhas em fase de finalização, quatro tipos de gorduras foram feitas com 8% de MS e foram testados tipos de gorduras foram testados: 1 gordura saturada sem proteção (GSSP, 2 gordura saturada protegida (GSP, 3 gordura insaturada sem proteção (GISP e 4 gordura insaturada protegida (GIP. Para estimar a cinética e a extensão da degradação da MS e cinética da produção de gás, as rações foram avaliadas mediante a técnica in vitro de produção de gás, seguindo os modelos propostos por Orskov e McDonald (1979 y France et al (1993, para isto foi empregado o procedimento PROC NLIN de SAS (2001. Ao mesmo tempo, foi realizado um analise de medidas repetidas no tempo para verificar o efeito dos tratamentos sobre a produção de gás e a degradação da MS no tempo com ajuda do procedimento PROC MIXED do SAS (2001. Neste experimento verificou-se que a utilização de gorduras insaturadas protegidas não afetou a degradação de MS quando comparadas com as não protegidas. No caso das gorduras saturadas, não houve um claro efeito da proteção sob a degradação e a cinética de fermentação da MS.Experimental cultivate cladocerans Daphnia magna feed with probiotics was realized. At University of Antioquia, Faculty of Agrarian Science, Larviculture, fish and food live Laboratory (Larpeali, under controlled conditions of environmental temperature between (21 - 25 °C, water temperature (22 - 23°C and pH (7.6, were performed. One diet of Saccharomyces cereviseae was used and one enriched medium of oat-soy flour (fatty acid, n-6 to concentrations of diet and enriched medium were the same, 25 ppm and 12.5 ppm, 2x2 factorial treatment arrangements (2 levels of Saccharomyces cereviseae and 2 levels of oat-soy flour, diets was fed to four replicates of Daphnia culture per treatment in order to determine their effects on the populations cultivated. A 15-days feeding, each third day, trial were conducted, to assess the organisms at final period. The results showed significant high difference (p0.05. The results showed that the combination of their high concentrations of components enhanced the population growth of Daphnia magna, reaching a number of micr

  15. CULTURAL VALUES

    OpenAIRE

    Harun, Sudarmin,Dr.S.Arts.SS.M.Hum

    2012-01-01

    This study aimed at finding and elaborating: (1) the cultural symbols, their kinds, their morphemic, literal, and idiomatic meanings, applied in BTS; (2) the aspect of values and their significant meanings, reflected by the cultural symbols in BTS; (3) The significant meanings and the aims of cultural symbols used by Buginese community, which are still relevant in marriage, inauguration, and political contexts.

  16. Observational Tests of Intergalactic Enrichment Models

    OpenAIRE

    Aguirre, Anthony; Schaye, Joop

    2005-01-01

    We summarize recent results assessing the carbon and silicon abundances of the intergalactic medium (IGM) using the `pixel optical depth' technique. We briefly discuss the implications of these results for models of intergalactic enrichment, focusing on distinguishing `early' z >> 4 enrichment by the first generations of stars and objects from `late' enrichment by 2 < z < 5 Ly-break galaxies. We then discuss the comparison of observed QSO spectra to simulated spectra generat...

  17. EURODIF: the uranium enrichment by gaseous diffusion

    International Nuclear Information System (INIS)

    During the seventies the nuclear power programme had an extremely rapid growth rate which entailed to increase the world uranium enrichment capacity. EURODIF is the largest undertaking in this field. This multinational joint venture built and now operates and enrichment plant using the gaseous diffusion process at Tricastin (France). This plant is delivering low enriched uranium since two years and has contracted about 110 million SWU's till 1990. Description, current activity and prospects are given in the paper. (Author)

  18. A mixture of nitrite-oxidizing and denitrifying microorganisms affects the ?18O of dissolved nitrate during anaerobic microbial denitrification depending on the ?18O of ambient water

    Science.gov (United States)

    Wunderlich, Anja; Meckenstock, Rainer U.; Einsiedl, Florian

    2013-10-01

    The stable isotopes 15N/14N and 18O/16O of nitrate are frequently used to determine sources of nitrate and to assess denitrification processes in the environment. Nitrate isotope ratios are thought to be conservative unless involved in (bio-) chemical conversion processes. Thus, stable isotopes are considered to be a reliable tool to determine sources of nitrate in aquatic habitats even after transport and dilution has occurred. Denitrification is known to shift both isotope ratios towards higher ?-values. A fixed ratio of 0.5 for ??18O/??15N has been proposed and has been widely used to detect denitrification in terrestrial environments, predominantly in aquifers. However, it is observed in environmental and laboratory studies that this ratio actually varies between less than 0.5 and 1 for uncertain reasons with laboratory studies usually describing a ratio close to 1. Here we report results of anoxic incubation experiments with natural populations of nitrate-reducing microorganisms using sediments from three different environments. In our experiments we used water with a ?18O in excess of 500‰ and found a microbially mediated influence of the oxygen isotopic composition of ambient water on the isotopic composition of the residual dissolved nitrate. We found up to 5.7 ± 2.3% of the oxygen-atoms in the residual dissolved nitrate was exchanged by oxygen-atoms from ambient water within the limited timeframe of the experiments. The fastest incorporation of oxygen-atoms from water into dissolved nitrate correlated with the highest intermittent nitrite concentrations observed in our experiments. In a second series of batch experiments we also found that pure cultures of the nitrite-oxidizing bacterium Nitrobacter vulgaris promoted the incorporation of oxygen atoms from ambient water into dissolved nitrate under anoxic conditions. Presumably this happens via a reoxidation of intermediary formed nitrite by the enzyme "nitrite oxidoreductase" (NXR) in concurrence with respiratory nitrate reduction. In this context, our hypothesis is a reversibility of the reactions at the NXR enzyme even in the absence of external electron acceptors for nitrite oxidation. We suggest that the presence of nitrite-oxidizing microorganisms in aquatic environments may catalyse such an incorporation of oxygen-atoms stemming from ambient water into nitrate. This process may thus mask the original ?18O value of nitrate sources during denitrification and also distort the observed enrichment of 18O that is ascribed to denitrification. Our results are highly likely an explanation of the deviation of the described variable ??18O/??15N ratios for denitrification in terrestrial field studies from the values observed in the laboratory on pure cultures.

  19. Internet culture

    CERN Document Server

    Porter, David

    2013-01-01

    The internet has recently grown from a fringe cultural phenomenon to a significant site of cultural production and transformation. Internet Culture maps this new domain of language, politics and identity, locating it within the histories of communication and the public sphere. Internet Culture offers a critical interrogation of the sustaining myths of the virtual world and of the implications of the current mass migration onto the electronic frontier. Among the topics discussed in Internet Culture are the virtual spaces and places created by the citizens of the Net and their claims to the hot

  20. Community relations and uranium enrichment in Louisiana

    International Nuclear Information System (INIS)

    Louisiana Energy Services (L-E-S) will build the nation's first privately owned enrichment plant at the Claiborne Enrichment Center in Louisiana using centrifuge enrichment technology to separate physically uranium 238 from uranium 235. The waste will contain depleted uranium fluoride DUF6 that still contains approximately 40 percent of its original U235. It will be stored in 300 cylinders a year at the Claiborne Enrichment Center. There will be about 16,000 pounds of low level waste, which consists of the usual paper, clothing and wipes. In addition there will be about 1,500 pounds of activated carbon and 1,850 pounds of ventilation filters annually

  1. Cultural tourism and tourism cultures

    DEFF Research Database (Denmark)

    Ooi, Can-Seng

    2002-01-01

    Presenting a comprehensive and dynamic understanding of cultural tourism, this volume examines cultural mediators and how they help tourists appreciate foreign cultures. It also shows how tourism experiences are strategically crafted by mediators, the complexity of the mediation process, and how various products are mediated differently. A number of different products are investigated, including destination brand identities, "living" cultures and everyday life, art and history. The author illust...

  2. Uranium enrichment and the environment

    International Nuclear Information System (INIS)

    The three gaseous diffusion plants comprise one of the largest industrial complexes in the free world. Since all of the enrichment is done inside a very large plumbing maze, the control of radioactivity does not present a serious problem. Conventional, nonexotic engineering and administrative measures adequately control the minor levels of radioactivity associated with support activities such as equipment decontamination and maintenance. The treatment and control of chemical waste streams to comply with Federal and state regulations has required the commitment of 47 million dollars since 1974. Through 1982, an additional 84 million dollars may be required. The high cost is not a reflection of initially poor conditions but is rather the result of providing large treatment systems to meet very low discharge limits. Examples that will be discussed include airborne particulate removal, recirculating cooling water treatment, and hazardous waste disposal concepts

  3. IPNS enriched uranium booster target

    International Nuclear Information System (INIS)

    Since startup in 1981, IPNS has operated on a fully depleted 238U target. With the booster as in the present system, high energy protons accelerated to 450 MeV by the Rapid Cycling Synchrotron are directed at the target and by mechanisms of spallation and fission of the uranium, produce fast neutrons. The neutrons from the target pass into adjacent moderator where they slow down to energies useful for spectroscopy. The target cooling systems and monitoring systems have operated very reliably and safely during this period. To provide higher neutron intensity, we have developed plans for an enriched uranium (booster) target. HETC-VIM calculations indicate that the target will produce approx.90 kW of heat, with a nominal x5 gain (k/sub eff/ = 0.80). The neutron beam intensity gain will be a factor of approx.3. Thermal-hydraulic and heat transport calculations indicate that approx.1/2 in. thick 235U discs are subject to about the same temperatures as the present 238U 1 in. thick discs. The coolant will be light demineralized water (H2O) and the coolant flow rate must be doubled. The broadening of the fast neutron pulse width should not seriously affect the neutron scattering experiments. Delayed neutrons will appear at a level about 3% of the total (currently approx.0.5%). This may affect backgrounds in some experiments, so that we are assessing measures to control and correct for this (e.g., beam tube choppers). Safety analyses and neutronic calculations are nearing completion. Construction of the 235U discs at the ORNL Y-12 facility is scheduled to begin late 1985. The completion of the booster target and operation are scheduled for late 1986. No enriched uranium target assembly operating at the projected power level now exists in the world. This effort thus represents an important technological experiment as well as being a ''flux enhancer''

  4. Anaerobic degradation of propane and butane by sulfate-reducing bacteria enriched from marine hydrocarbon cold seeps

    OpenAIRE

    Jaekel, Ulrike; Musat, Niculina; Adam, Birgit; Kuypers, Marcel; Grundmann, Olav; Musat, Florin

    2012-01-01

    The short-chain, non-methane hydrocarbons propane and butane can contribute significantly to the carbon and sulfur cycles in marine environments affected by oil or natural gas seepage. In the present study, we enriched and identified novel propane and butane-degrading sulfate reducers from marine oil and gas cold seeps in the Gulf of Mexico and Hydrate Ridge. The enrichment cultures obtained were able to degrade simultaneously propane and butane, but not other gaseous alkanes. They were cold-...

  5. Stochastic self-enrichment, pre-enrichment, and the formation of globular clusters

    OpenAIRE

    Bailin, Jeremy; Harris, William E.

    2009-01-01

    We develop a model for stochastic pre-enrichment and self-enrichment in globular clusters (GCs) during their formation process. GCs beginning their formation have an initial metallicity determined by the pre-enrichment of their surrounding protocloud, but can also undergo internal self-enrichment during formation. Stochastic variations in metallicity arise because of the finite numbers of supernova. We construct an analytic formulation of the combined effects of pre-enrichme...

  6. Microbial community structure and function in response to the shift of sulfide/nitrate loading ratio during the denitrifying sulfide removal process.

    Science.gov (United States)

    Huang, Cong; Li, Zhi-Ling; Chen, Fan; Liu, Qian; Zhao, You-Kang; Zhou, Ji-Zhong; Wang, Ai-Jie

    2015-12-01

    Influence of acetate-C/NO3(-)-N/S(2-) ratio to the functional microbial community during the denitrifying sulfide removal process is poorly understood. Here, phylogenetic and functional bacterial community for elemental sulfur (S(0)) recovery and nitrate (NO3(-)) removal were investigated with the switched S(2-)/NO3(-) molar ratio ranged from 5/2 to 5/9. Optimized S(2-)/NO3(-) ratio was evaluated as 5/6, with the bacterial genera predominated with Thauera, Enterobacter, Thiobacillus and Stappia, and the sqr gene highly expressed. However, insufficient or high loading of acetate and NO3(-) resulted in the low S(0) recovery, and also significantly modified the bacterial community and genetic activity. With S(2-)/NO3(-) ratio of 5/2, autotrophic S(2-) oxidization genera were dominated and NO3(-) reduction activity was low, confirmed by the low expressed nirK gene. In contrast, S(2-)/NO3(-) ratio switched to 5/8 and 5/9 introduced diverse heterotrophic nitrate reduction and S(0) over oxidization genera in accompanied with the highly expressed nirK and sox genes. PMID:26340031

  7. Nitrogen-removal efficiency of a novel aerobic denitrifying bacterium, Pseudomonas stutzeri strain ZF31, isolated from a drinking-water reservoir.

    Science.gov (United States)

    Huang, Tinglin; Guo, Lin; Zhang, Haihan; Su, Junfeng; Wen, Gang; Zhang, Kai

    2015-11-01

    An aerobic denitrifier, identified as Pseudomonas stutzeri strain ZF31, was isolated from the Zhoucun drinking-water reservoir. Strain ZF31 removed 97% of nitrate nitrogen after 16h, without nitrite accumulation. Sequence amplification indicated the presence of the denitrification genes napA, nirS, norB, and nosZ. Nitrogen balance analysis revealed that approximately 75% of the initial nitrogen was removed as gas products. Response surface methodology (RSM) experiments showed that maximum removal of total nitrogen (TN) occurred at pH 8.23, a C/N ratio of 6.68, temperature of 27.72°C, and with shaking at 54.15rpm. The TN removal rate at low C/N ratio (i.e., 3) and low temperature (i.e., 10°C) was 73.30% and 60.08%, respectively. These results suggest that strain ZF31 has potential applications for the bioremediation of slightly polluted drinking-water reservoirs. PMID:26241840

  8. Providing incentives to buy US enrichment

    International Nuclear Information System (INIS)

    The U.S. Department of Energy is making a series of commercial and technological decisions crucial to its future as an enriching enterprise. The state of US enrichment, as revealed in this years AIF Fuel Cycle conference, is reported. (U.K.)

  9. Enrichment Monitor for 235U Fuel Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Winn, W.G.

    2001-08-22

    This report describes the performance of this prototype y-monitor of 235 Uranium enrichment. In this proposed method y-rates associated with 235U and 232U are correlated with enrichment. Instrumentation for appraising fuel tubes with this method has been assembled and tested.

  10. After-School Enrichment: Extending Learning Time

    Science.gov (United States)

    Sanger, Carla

    2011-01-01

    After-school programs can help show students how academics are relevant to their personal interests, and serve as training grounds for future teachers. This article features LA's BEST After School Enrichment Program whose mission is to provide a safe and supervised after school education, enrichment, and recreation program for children ages 5 to…

  11. Perspectives for the uranium enrichment in Brazil

    International Nuclear Information System (INIS)

    Through an analysis of the electrical energy future in Brazil, the needs for enriched uranium are discussed, and therefore the importance of developing local capability for self-production. A description of the production processes that are well established is given first, then the analysis itself is performed and finally a visualization of the International Market for enriched uranium is shown. (author)

  12. A Duality of Quantale-Enriched Categories

    OpenAIRE

    Hofmann, Dirk; Waszkiewicz, Pawel

    2010-01-01

    We describe a duality for quantale-enriched categories that extends the Lawson duality for continuous dcpos: for any saturated class J of modules that commute with certain weighted limits, and under an appropriate choice of morphisms, the category of J-cocomplete and J-continuous quantale-enriched categories is self-dual.

  13. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes, Francisco J., E-mail: fjcervantes@ipicyt.edu.mx [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Mancilla, Ana Rosa; Toro, E. Emilia Rios-del [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico)

    2011-11-15

    Highlights: {yields} Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. {yields} Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. {yields} Several species from classes {beta}-, {delta}- and {gamma}-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 {mu}M of benzene were degraded, which corresponds to 279 {+-} 27 micro-electron equivalents ({mu}Eq) L{sup -1}, linked to the reduction of 619 {+-} 81 {mu}Eq L{sup -1} of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two {gamma}-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes {beta}-, {delta}- and {gamma}-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  14. Uranium enrichment capacity: public versus private ownership

    International Nuclear Information System (INIS)

    Continual growth of conventional nuclear capacity requires an assured supply of enriched uranium and, hence, potential expansion of domestic uranium enrichment capacity. The question of ownership of new enrichment capacity, i.e., public or private, entails not only the social-opportunity costs of alternative investments but also technical parameters of uranium utilization and advanced reactor development. Inclusion of risk preferences in both the public and private sectors produces interesting results in terms of optimal investment strategies with respect to choice of technology and scale of investment. Utilization of a nuclear fuel cycle requirements process model allows explicit specification of production technology. Integration of process model output with a least-cost investment model permits flexibility in parametric analysis. Results indicate minimum incentive for Government subsidy of a private enrichment sector through 2000 given moderate to low nuclear growth assumptions. The long-run scenario, to 2020, exhibits potentially greater incentives for private enrichment investment

  15. Current perspective of the uranium enrichment market

    International Nuclear Information System (INIS)

    Over the past several years, developments in the uranium enrichment market have required the Department of Energy (DOE) to make a number of changes in the U.S. enrichment enterprise. These changes have been made to allow DOE to conduct our enrichment business so as to be more responsive to changing market forces. Needless to say, some of these changes have been difficult, but they have been necessary if they are to conduct a healthy and competitive uranium enrichment business in the United States. This paper discusses several topics, including: The Uranium Enrichment Market, Utility Services (US) Contracts, Reduced Prices, Incentive Pricing, Better Customer Services, and Advanced Technology. In addition to these topics, information is provided on the recent court action regarding the US Contracts and the viability finding on the uranium mining industry

  16. Culture evolves

    OpenAIRE

    Whiten, Andrew; Hinde, Robert A.; Laland, Kevin N.; Stringer, Christopher B.

    2011-01-01

    Culture pervades human lives and has allowed our species to create niches all around the world and its oceans, in ways quite unlike any other primate. Indeed, our cultural nature appears so distinctive that it is often thought to separate humanity from the rest of nature and the Darwinian forces that shape it. A contrary view arises through the recent discoveries of a diverse range of disciplines, here brought together to illustrate the scope of a burgeoning field of cultural evolution and to...

  17. Analysis of Culture(s), Culture(s) of Analysis

    OpenAIRE

    LEONE, Massimo

    2009-01-01

    PROGRAMMA Saturday September 5, 2009 Chair: Eero Tarasti, President of the International Association for Semiotic Studies 16:00 Winfried Nöth, University of Kassel Machines of Cultures and Cultures of Machines 17:00 Break 17:15 Gianfranco Marrone, University of Palermo Text, Discourse, Culture 18:15 Roundtable 1 Sunday September 6, 2009 10:00 Claudio Guerri, University of Buenos Aires The Semiotic Nonagon and the Graphic Language TSD: an operative model for ...

  18. Talking Culture

    DEFF Research Database (Denmark)

    Holmgreen, Lise-Lotte

    2010-01-01

    When Danish businesses move production abroad, ‘culture’ is often seen as a huge challenge to the successful outcome of cross-border collaboration. Therefore, business leaders often seek information and guidelines of how to cope in the vast amount of literature on culture and intercultural communication. Much of this literature is based on functionalist approaches providing the dos and don’ts of intercultural encounters. This involves inter alia conceptualising ‘culture’ as a relatively fixed, h...

  19. Beyond culture

    OpenAIRE

    Levine, Peter (Peter Lawrence)

    1991-01-01

    ?This dissertation examines Friedrich Nietzsche's theory of culture. Nietzsche held that all beliefs were arbitrary and culturally contingent; cultures were distinct, organic, homogeneous entities, whose values were mutually incommensurable. I trace the origins of this theory to Nietzsche's experience as a philologist; but I claim that, in deriving his theory from historical data, Nietzsche drew false conclusions. As a mature philosopher, Nietzsche developed a somewhat mo...

  20. Manuscript Cultures

    DEFF Research Database (Denmark)

    2014-01-01

    What do Mesoamerica, Greece, Byzantium, Island, Chad, Ethiopia, India, Tibet, China and Japan have in common? Like many other cultures of the world, they share a particular form of cultural heritage: ancient handwritten documents. In 2007, scholars from some20 countries around the world gathered at the University of Copenhagen for a workshop on manuscripts to compare notes. This event led to the publication of this volume, which brings together16 articles on philological, cultural, and material ...

  1. Characterization of four TCE-dechlorinating microbial enrichments grown with different cobalamin stress and methanogenic conditions.

    Science.gov (United States)

    Men, Yujie; Lee, Patrick K H; Harding, Katie C; Alvarez-Cohen, Lisa

    2013-07-01

    To investigate the important supportive microorganisms responsible for trichloroethene (TCE) bioremediation under specific environmental conditions and their relationship with Dehalococcoides (Dhc), four stable and robust enrichment cultures were generated using contaminated groundwater. Enrichments were maintained under four different conditions exploring two parameters: high and low TCE amendments (resulting in inhibited and uninhibited methanogenic activity, respectively) and with and without vitamin B?? amendment. Lactate was supplied as the electron donor. All enrichments were capable of reductively dechlorinating TCE to vinyl chloride and ethene. The dechlorination rate and ethene generation were higher, and the proportion of electrons used for dechlorination increased when methanogenesis was inhibited. Biologically significant cobalamin biosynthesis was detected in the enrichments without B?? amendment. Comparative genomics using a genus-wide microarray revealed a Dhc genome similar to that of strain 195 in all enrichments, a strain that lacks the major upstream corrin ring biosynthesis pathway. Seven other bacterial operational taxonomic units (OTUs) were detected using clone libraries. OTUs closest to Pelosinus, Dendrosporobacter, and Sporotalea (PDS) were most dominant. The Clostridium-like OTU was most affected by B?? amendment and active methanogenesis. Principal component analysis revealed that active methanogenesis, rather than vitamin B?? limitation, exerted a greater effect on the community structures even though methanogens did not seem to play an essential role in providing corrinoids to Dhc. In contrast, acetogenic bacteria that were abundant in the enrichments, such as PDS and Clostridium sp., may be potential corrinoid providers for Dhc. PMID:23640361

  2. The role of work-family enrichment in work-life balance & career success

    OpenAIRE

    Shah, Shalaka Sharad

    2014-01-01

    The issue of work-life balance is becoming increasingly important for employers and employees globally. The clearer becomes our understanding about this issue; the better it will be for an effective and positive integration of these dynamic domains of our lives. Work-family enrichment is a positive way of integrating work and family and it helps to achieve work-life balance. In this Indo-German study, work-life balance, work-family enrichment, work-family culture and career success are analys...

  3. Conversion of Crude Oil to Methane by a Microbial Consortium Enriched From Oil Reservoir Production Waters

    Directory of Open Access Journals (Sweden)

    LisaGieg

    2014-05-01

    Full Text Available The methanogenic biodegradation of crude oil is an important process occurring in petroleum reservoirs and other oil-containing environments such as contaminated aquifers. In this process, syntrophic bacteria degrade hydrocarbon substrates to products such as acetate, and/or H2 and CO2 that are then used by methanogens to produce methane in a thermodynamically dependent manner. We enriched a methanogenic crude oil-degrading consortium from production waters sampled from a low temperature heavy oil reservoir. Alkylsuccinates indicative of fumarate addition to C5 and C6 n-alkanes were identified in the culture (above levels found in controls, corresponding to the detection of an alkyl succinate synthase gene (assA in the culture. In addition, the enrichment culture was tested for its ability to produce methane from residual oil in a sandstone-packed column system simulating a mature field. Methane production rates of up 5.8 ?mol CH4/g of oil/day were measured in the column system. Amounts of produced methane were in relatively good agreement with hydrocarbon loss showing depletion of more than 50% of saturate and aromatic hydrocarbons. Microbial community analysis revealed that the enrichment culture was dominated by members of the genus Smithella, Methanosaeta, and Methanoculleus. However, a shift in microbial community occurred following incubation of the enrichment in the sandstone columns. Here, Methanobacterium sp. were most abundant, as were bacterial members of the genus Pseudomonas and other known biofilm forming organisms. Our findings show that microorganisms enriched from petroleum reservoir waters can bioconvert crude oil components to methane both planktonically and in sandstone-packed columns as test systems. Further, the results suggest that different organisms may contribute to oil biodegradation within different phases (e.g., planktonic versus sessile within a subsurface crude oil reservoir.

  4. Profile of World Uranium Enrichment Programs-2009

    International Nuclear Information System (INIS)

    It is generally agreed that the most difficult step in building a nuclear weapon is acquiring fissile material, either plutonium or highly enriched uranium (HEU). Plutonium is produced in a nuclear reactor, whereas HEU is produced using a uranium enrichment process. Enrichment is also an important step in the civil nuclear fuel cycle, in producing low enriched uranium (LEU) for use as fuel for nuclear reactors to generate electricity. However, the same equipment used to produce LEU for nuclear reactor fuel can also be used to produce HEU for weapons. Safeguards at an enrichment plant are the array of assurances and verification techniques that ensure uranium is not diverted or enriched to HEU. There are several techniques for enriching uranium. The two most prevalent are gaseous diffusion, which uses older technology and requires a lot of energy, and gas centrifuge separation, which uses more advanced technology and is more energy efficient. Gaseous diffusion plants (GDPs) provide about 40% of current world enrichment capacity but are being phased out as newer gas centrifuge enrichment plants (GCEPs) are constructed. Estimates of current and future enrichment capacity are always approximate, due to the constant upgrades, expansions, and shutdowns occurring at enrichment plants, largely determined by economic interests. Currently, the world enrichment capacity is approximately 56 million kilogram separative work units (SWU) per year, with 22.5 million in gaseous diffusion and more than 33 million in gas centrifuge plants. Another 34 million SWU/year of capacity is under construction or planned for the near future, almost entirely using gas centrifuge separation. Other less-efficient techniques have also been used in the past, including electromagnetic and aerodynamic separations, but these are considered obsolete, at least from a commercial perspective. Laser isotope separation shows promise as a possible enrichment technique of the future but has yet to be demonstrated commercially. In the early 1980s, six countries developing gas centrifuge technology (United States, United Kingdom, Germany, the Netherlands, Japan, and Australia) along with the International Atomic Energy Agency and the European Atomic Energy Community began developing effective safeguards techniques for GCEPs. This effort was known as the Hexapartite Safeguards Project (HSP). The HSP had the goal of maximizing safeguards effectiveness while minimizing the cost to the operator and inspectorate, and adopted several recommendations, such as the acceptance of limited-frequency unannounced access inspections in cascade halls, and the use of nondestructive assay measurements and tamper-indicating seals. While only the HSP participants initially committed to implementing all the measures of the approach, it has been used as a model for the safeguards applied to GCEPs in additional states. Uranium enrichment capacity has continued to expand on all fronts in the last few years. GCEP capacity is expanding in anticipation of the eventual shutdown of the less-efficient GDPs, the termination of the U.S.-Russia HEU blend-down program slated for 2013, and the possible resurgence of nuclear reactor construction as part of an expected 'Nuclear Renaissance'. Overall, a clear trend in the world profile of uranium enrichment plant operation is the continued movement towards multinational projects driven by commercial and economic interests. Along this vein, the safeguards community is continuing to develop new safeguards techniques and technologies that are not overly burdensome to enrichment plant operators while delivering more effective and efficient results. This report provides a snapshot overview of world enrichment capacity in 2009, including profiles of the uranium enrichment programs of individual states. It is a revision of a 2007 report on the same topic; significant changes in world enrichment programs between the previous and current reports are emphasized. It is based entirely on open-source information, which is dependent on published sources and may theref

  5. Student science enrichment training program

    Energy Technology Data Exchange (ETDEWEB)

    Sandhu, S.S.

    1994-08-01

    This is a report on the Student Science Enrichment Training Program, with special emphasis on chemical and computer science fields. The residential summer session was held at the campus of Claflin College, Orangeburg, SC, for six weeks during 1993 summer, to run concomitantly with the college`s summer school. Fifty participants selected for this program, included high school sophomores, juniors and seniors. The students came from rural South Carolina and adjoining states which, presently, have limited science and computer science facilities. The program focused on high ability minority students, with high potential for science engineering and mathematical careers. The major objective was to increase the pool of well qualified college entering minority students who would elect to go into science, engineering and mathematical careers. The Division of Natural Sciences and Mathematics and engineering at Claflin College received major benefits from this program as it helped them to expand the Departments of Chemistry, Engineering, Mathematics and Computer Science as a result of additional enrollment. It also established an expanded pool of well qualified minority science and mathematics graduates, which were recruited by the federal agencies and private corporations, visiting Claflin College Campus. Department of Energy`s relationship with Claflin College increased the public awareness of energy related job opportunities in the public and private sectors.

  6. Nutraceutical enriched Indian traditional chikki.

    Science.gov (United States)

    Ramakrishna, Chetana; Pamisetty, Aruna; Reddy, Sunki Reddy Yella

    2015-08-01

    Chikki or peanut brittle, a traditional sweet snack was chosen as vehicle for enrichment with added natural nutraceuticals through herbs. The formulation and process for preparation of chikki with added herbs like ashwagandha (Withania somenifera), tulasi (Ocimumsanctum L.) and ajwain (Trachyspermum ammi S.) were standardized. The polyphenol content of chikki with added herbs ranged 0.29-0.46 g/100 g. Among the herbs, ajwain showed more potent antioxidant activity followed by tulasi, whereas ashwagandha and product prepared with it showed the least activity. Total carotenoid contents of chikki with added herbs ranged between 1.5 and 4.3 mg/100 g. Storage studies showed that chikki prepared with tulasi and ajwain were sensorily acceptable up to 90 days, while rancid notes were observed in control and chikki with added ashwagandha at the end of 30 days. Thus chikki with added herbs in addition to containing natural nutraceuticals like polyphenols and carotenoids had improved storage stability compared to control. PMID:26243935

  7. Mortality among uranium enrichment workers

    International Nuclear Information System (INIS)

    A retrospective cohort mortality study was conducted on workers at the Portsmouth Uranium Enrichment facility in Pike County, Ohio, in response to a request from the Oil, Chemical and Atomic Workers International Local 3-689 for information on long-term health effects. Primary hazards included inhalation exposure to uranyl fluoride containing uranium-235 and uranium-234, technetium-99 compounds, and hydrogen-fluoride. Uranium-238 presented a nephrotoxic hazard. Statistically significant mortality deficits based on U.S. death rates were found for all causes, accidents, violence, and diseases of nervous, circulatory, respiratory, and digestive systems. Standardized mortality rates were 85 and 54 for all malignant neoplasms and for other genitourinary diseases, respectively. Deaths from stomach cancer and lymphatic/hematopoietic cancers were insignificantly increased. A subcohort selected for greatest potential uranium exposure has reduced deaths from these malignancies. Insignificantly increased stomach cancer mortality was found after 15 years employment and after 15 years latency. Routine urinalysis data suggested low internal uranium exposures

  8. Enriching the hot circumgalactic medium

    CERN Document Server

    Crain, Robert A; Schaye, Joop; Frenk, Carlos S; Theuns, Tom

    2013-01-01

    Models of galaxy formation in a CDM universe predict that massive galaxies are surrounded by a hot, quasi-hydrostatic circumgalactic corona of slowly cooling gas, predominantly accreted from the IGM. This prediction is borne out by the cosmological hydrodynamical simulations of Crain et al., which reproduce scaling relations between the X-ray and optical properties of nearby disc galaxies. Such coronae are metal poor, but observations of the X-ray emitting circumgalactic medium (CGM) of local galaxies typically indicate enrichment to near-solar iron abundance, potentially signalling a shortcoming in galaxy formation models. We show here that, while the hot CGM of galaxies formed in the simulations is metal poor in a mass-weighted sense, its X-ray luminosity-weighted metallicity is often close to solar. This bias arises because the soft X-ray emissivity of a typical 0.1 keV corona is dominated by collisionally-excited metal ions that are synthesised in stars and recycled into the hot CGM. We find that these me...

  9. Addressing Culture in the efl Classroom: A Dialogic Proposal

    OpenAIRE

    Álvarez Valencia José Aldemar; Bonilla Medina Ximena

    2009-01-01

    Language teaching has gone from a linguistic centered approach towards a lingo-cultural experience in which learning a language goes hand in hand with the understanding of not only the target culture, but the learner’s own culture. This paper attempts to describe and reflect upon a collaborative and dialogical experience carried out between two teachers of the Languages Program of Universidad de la Salle, in Bogotá. The bilateral enrichment of such a pedagogical experience helped the teachers...

  10. Methods for Enhanced Culture Recovery of Francisella tularensis

    OpenAIRE

    Petersen, Jeannine M.; Schriefer, Martin E; Gage, Kenneth L; Montenieri, John A.; Carter, Leon G.; Stanley, Miles; Chu, May C.

    2004-01-01

    Francisella tularensis is found in a wide variety of hosts and extrahost environments, making culture recovery a diagnostic challenge. Here we demonstrate improved recovery times and good sensitivity (90%) when cultures were inoculated on the site of an investigation using fresh tissues. For contaminated specimens, antibiotic supplementation of enriched cysteine heart agar blood culture medium improved recovery of F. tularensis by 81.1%. For transport of tissues, immediate freezing yielded cu...

  11. Digital Culture

    OpenAIRE

    Lavender, AM

    2010-01-01

    This chapter outlines some of the underlying features of digital culture, in order to see how they apply to – and help shape – intermedial theatre and performance. It synthesises accounts of digital technology and contemporary cultural production to argue for a distinctive set of characteristics to recent intermedial performance.

  12. Cultural citizenship

    Directory of Open Access Journals (Sweden)

    Toby Miller

    2011-12-01

    Full Text Available Cultural citizenship is a concept whose time has come. Following on from political citizenship--the right to reside and to vote--and economic citizenship--the right to thrive and prosper--it insists on a right to communication and to the representation of cultural difference.

  13. DOE enrichment plants-safeguards means business

    International Nuclear Information System (INIS)

    The Portsmouth Gaseous Diffusion Plant, owned by the US Department of Energy (DOE) and operated by Martin Marietta Energy Systems, Inc., is a full service enrichment plant. Its long enriching cascade can process uranium hexafluoride (UF6) feeds at almost any 235U level and can produce UF6 over the complete spectrum from depleted to very highly enriched uranium. The DOE uranium enrichment program is a government-owned enterprise operating as a business. The operating concerns of the DOE uranium enrichment plants and their safeguards programs have evolved together over the past three decades, and that evolution will likely continue. As the risk associated with possession, processing, and shipment of strategic nuclear material increased, the protection and control of it increased; as the value of the product grew with time, better ways were found to measure and conserve it. In each of these areas, safeguards objectives and the business requirements of the plant are complementary, and the progress made in one area has been reflected by progress in the other. The plant's material control and accountability program has become crucial to such business requirements as quantifying the enriched uranium (separative work units) produced in each monthly period and convincing financial auditors that the multibillion dollar enriched uranium assets located at the Portsmouth plant are properly stated

  14. Developments in world enrichment supply and economics

    International Nuclear Information System (INIS)

    The paper discusses the supply and demand situation for enriched uranium in the 1990s, how advanced technology can impact the market and the restructuring of the United States uranium enrichment enterprise. In the 1990s, utilities are expected to spend about US $2.5 billion per year for enrichment services. (One billion = 109). Enrichment demand in the world outside centrally planned economies area should increase through the 1990s, from 25 million separate work units today to over 30 million by 2000. However, there should be a plentiful supply of enriched uranium at reasonable prices in the 1990s. It appears that the world enrichment market will become even more competitive, with additional suppliers entering the market. The United States of America and other countries are actively developing advanced technology, since it promises lower prices. There is a strong incentive to be the first to develop and deploy advanced technology. The USA is in the process of restructuring its enrichment enterprise to give it added stability and flexibility. (author). 8 figs

  15. World enrichment services market 1990-2005

    International Nuclear Information System (INIS)

    Growth in world enrichment capacity, already in oversupply, will lead to a very competitive enrichment services market by the second half of the 1990s. Three of the four primary enrichment suppliers (USDOE, Eurodif, and Urenco) already have the capacity to produce 33 million SWU per year. Explorts from the Soviet Union and the People's Republic of China (PRC) currently make available an additional six million SWU per year, and that figure could rise substantially. With additional supply capability expected from China, the Soviet Union, Louisiana Energy Services (LES) and Isotope Technologies (ITI), and the increased capacity of Urenco, and possibly even AVLIS from DOE, enrichment supply capability could exceed 46 million SWU per year by the year 2000. Yet annual enrichment requirements are only estimated to grow from 23.5 million SWU in 1990, to 28.9 million SWU by 2000. Total unfilled enrichment requirements will rise significantly in the second half of the 1990s, particularly from US utilities, creating sales opportunities for which suppliers will compete aggressively. These factors foretell a very competitive market in which sellers will offer low prices and flexible contracts. The anticipation of such strong competition also raises the question of which enrichment technology will succeed, and puts tremendous pressure on all suppliers to find cost-effective means of production as quickly as possible

  16. Italian activities in uranium enrichment

    International Nuclear Information System (INIS)

    The paper describes Italian activities in uranium enrichment, which have mainly developed along the lines of the two classical processes: gaseous diffusion and centrifuges. Research, development and industrial activities play different roles in the two methods, and a special working group, GIAU, was established by CNEN to help co-ordinate this activity. In the field of gaseous diffusion, R and D effort was, from the start of the programme in 1968, mainly devoted to barriers and compressors, with the object of fully understanding the process and of demonstrating that it was capable of overcoming the main problems in this technology. Isotope separation of UF6 was demonstrated in 1974 at experimental plant level. Cost-sharing contracts were signed between CNEN and industries to build prototypes and ''first-of-a-kind'' components; small production lines have been set up to evaluate economics and assess production quality. Eurodif is partially associated with the development of this activity. On the industrial level, AGIP Nucleare and CNEN were among the promoters of the Eurodif venture from the beginning in 1973 and now own 25% of the shares. In the field of ultracentrifugation, work is still devoted mainly to R and D on the machines. The separation process was demonstrated in 1973 at laboratory level with a Zippe type centrifuge. Later activities aimed at developing high-capacity machines; different solutions are under close scrutiny. Carbon fibres and multiplerotor machines have been mechanically tested, and the first reference design of a small cascade plant has been completed. In the field of laser separation, after a complete and critical survey of different processes under development in other countries, experimental research work is now being undertaken, and experiments on basic aspects of the process are in progress. (author)

  17. The US Enrichment Corp.. Looking towards privatisation

    International Nuclear Information System (INIS)

    The United States Enrichment Corporation (USEC) was launched in 1993 with the intention of bringing private sector disciplines into the US enrichment industry. It is charged with operating as a business enterprise on a profitable and efficient basis, with maximizing the long term value of the Corporation to the Treasury and taxpayer, and with maintaining a reliable and economic source of enriched uranium. Though acting like a commercial business, it remains for the moment in US government ownership. The directors have an obligation, however, to recommend to the government in 1995 if, how and when the Corporation should be privatized. (UK)

  18. Purification and characterization of benzoate-coenzyme A ligase and 2-aminobenzoate-coenzyme A ligases from a denitrifying Pseudomonas sp.

    Science.gov (United States)

    Altenschmidt, U; Oswald, B; Fuchs, G

    1991-09-01

    The enzymes catalyzing the formation of coenzyme A (CoA) thioesters of benzoate and 2-aminobenzoate were studied in a denitrifying Pseudomonas sp. anaerobically grown with these aromatic acids and nitrate as sole carbon and energy sources. Three different rather specific aromatic acyl-CoA ligases, E1, E2, and E3, were found which catalyze the formation of CoA thioesters of benzoate, fluorobenzoates, and 2-aminobenzoate. ATP is cleaved into AMP and pyrophosphate. The enzymes were purified, their N-terminal amino acid sequences were determined, and their catalytic and molecular properties were studied. Cells anaerobically grown on benzoate and nitrate contain one CoA ligase (AMP forming) for benzoic acid (E1). It is a homodimer of Mr 120,000 which prefers benzoate as a substrate but shows some activity also with 2-aminobenzoate and fluorobenzoates, although with lower Km. Cells anaerobically grown on 2-aminobenzoate and nitrate contain three different CoA ligases for aromatic acids. The first one is identical with benzoate-CoA ligase (E1). The second enzyme is a 2-aminobenzoate-CoA ligase (E2). It is a monomer of Mr 60,000 which prefers 2-aminobenzoate but also activates benzoate, fluorobenzoates and, less effectively, 2-methylbenzoate, with lower affinities to the latter substrates. The enzymes E1 and E2 have similar activity levels; a third minor CoA ligase activity is due to a different 2-aminobenzoate-CoA ligase. The enzyme (E3) is a monomer of Mr, 65,000 which 2-aminobenzoate pathway (U. Altenschmidt, C. Eckerskorn, and G. Fuchs, Eur. J. Biochem. 194:647-653, 1990); apparently, it is not completely repressed under anaerobic conditions and therefore also is induced to a small extent by 2-aminobenzoate under anaerobic growth conditions. PMID:1885526

  19. Ammonium removal at low temperature by a newly isolated heterotrophic nitrifying and aerobic denitrifying bacterium Pseudomonas fluorescens wsw-1001.

    Science.gov (United States)

    Zhang, Shumei; Sha, Changqing; Jiang, Wei; Li, Weiguang; Zhang, Duoying; Li, Jing; Meng, Liqiang; Piao, Yongjian

    2015-10-01

    A heterotrophic nitrifier wsw-1001 was isolated from Songhua River and identified as Pseudomonas fluorescens. Ammonium removal by the strain at low temperature was investigated. The effect of initial ammonium concentration (from 5 to 1000?mg/L) and culture temperature (from 4°C to 30°C) on ammonium removal efficiency was studied. Biodegradation product, [Formula: see text], [Formula: see text], N2, N2O and intercellular N were monitored. The results indicated that the strain had potential for water and wastewater treatment. Ammonium could be removed by the strain at low temperature. Ammonium removal efficiency increased with temperature from 4°C to 20°C and decreased with ammonium concentration from 5 to 1000?mg/L. The strain exhibited a capability of heterotrophic nitrification and aerobic denitrification using [Formula: see text] as the sole nitrogen source at 8°C. [Formula: see text] and [Formula: see text] were reduced by the strain. Nitrogen balance analysis in the presence of 39.7?mg/L [Formula: see text] indicated that 71.2% [Formula: see text] was removed by converting to N2 (46.3%) and assimilating as biomass (42.5%). Substances such as [Formula: see text], [Formula: see text] and N2O were detected at very low concentrations. Ammonium mono-oxygenase, hydroxylamine oxidase, nitrite reductase and nitrate reductase activity were measured. The ammonium removal pathway of the strain was speculated to be [Formula: see text]. PMID:25827750

  20. 76 FR 34103 - In the Matter of Areva Enrichment Services, LLC (Eagle Rock Enrichment Facility); Notice of...

    Science.gov (United States)

    2011-06-10

    ...10-899-02-ML-BD01] In the Matter of Areva Enrichment Services, LLC (Eagle Rock Enrichment Facility); Notice of Hearing, (Notice...regarding the December 2008 application by AREVA Enrichment Services, LLC (AES) seeking a...

  1. 75 FR 10525 - In the Matter of: AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility) and All Other...

    Science.gov (United States)

    2010-03-08

    ...NRC-2009-0187] In the Matter of: AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility) and All Other Persons Who Seek...Program (Effective Immediately) I AREVA Enrichment Services, LLC (AES), has applied to...

  2. Structure of denitrifying communities reducing N2O at suboxic waters off northern Chile and Perú / Estructura de las comunidades desnitrificantes que reducen N2O en aguas subóxicas del norte de Chile y Perú

    Scientific Electronic Library Online (English)

    Maribeb, Castro-González; Osvaldo, Ulloa; Laura, Farías.

    2015-04-01

    Full Text Available El gen nosZ, el cual codifica para la reducción de N2O a N2, fue usado para estudiar la estructura de las comunidades desnitrificantes en la zona de mínimo oxígeno frente a las costas de Chile y Perú, a través del polimorfismo de los fragmentos largos de restricción terminal (PFLRT) y clonamiento de [...] los genes nosZ. El análisis del PFLRT mostró poca diversidad de genes nosZ en las profundidades subóxicas (núcleo de la zona de mínimo oxígeno-ZMO) comparado con las profundidades donde el O2 varío ampliamente (límite superior de la zona de mínimo oxígeno o LSZMO). Las comunidades desnitrificantes-nosZ presentaron diferencias en su estructura entre localidades geográficas y tiempo de muestreo sugiriendo asociación con la variación en las condiciones ambientales. El análisis de correspondencia canónica indicó que los parámetros ambientales seleccionados como variables predictoras (N2O, O2, NH4+ y NO2-) explicaron bien las diferencias en la composición de la comunidad nosZ entre sitios de muestreo. El análisis filogenético mostró poca diversidad de secuencias nosZ y agrupó el 81% de los clones cerca al clúster de secuencias de sedimentos del Pacífico. Las secuencias no se relacionaron con ninguna secuencia nosZ reportada en agua de mar, o de bacterias desnitrificantes conocidas, demostrando la novedad de los filotipos encontrados en esta área. Abstract in english The nosZ gene, which encodes for N2O reduction to N2, was used to study the structure of denitrifying communities in the oxygen minimum zone off Chilean and Peruvian coast throughout terminal restriction fragment length polymorphism (TRFLP) and cloning of nosZ genes. TRFLP analysis showed little div [...] ersity of nosZ genes at suboxic depths (Oxygen Minimum Zone´s core) compared with depths where O2 largely varied (upper limit of OMZ or ULOMZ). The nosZ-denitrifying communities showed differences in its structure between geographical locations and time sampling suggesting an association with the shift in the environmental conditions. The canonical correspondence analysis showed that the environmental parameters selected as predictor variables (N2O, O2, NH4+ and NO2-) explained well the differences in nosZ-denitrifying community composition among sampling sites. The phylogenetic analysis showed little nosZ sequence diversity and grouped 81% of nosZ-clones near the cluster of sediments sequences from Pacific. Our sequences did not branch with any known denitrifying bacteria or seawater nosZ-sequences available, demonstrating the novelty of phylotypes founded in this area.

  3. A Guide to Job Enrichment and Redesign.

    Science.gov (United States)

    Cunningham, J. Barton; Eberle, Ted

    1990-01-01

    Describes job design alternatives--job enrichment, the job characteristics model, Japanese style management, and quality-of-worklife approaches. Focuses on the problems that human resources professionals may encounter when attempting to implement these approaches. (Author/JOW)

  4. Management's Ecstasy and Disparity Over Job Enrichment

    Science.gov (United States)

    King, Albert S.

    1976-01-01

    A case study analyzing job enrichment schemes and manager expectations of increased productivity is presented. It was found that it was the managers' expectations of increased productivity, not the reorganization of work, that led to higher productivity. (EC)

  5. Job Enrichment: How to Avoid the Pitfalls

    Science.gov (United States)

    Tregoe, Benjamin B., Jr.

    1974-01-01

    While many job enrichment programs fail, a program called Analytical Trouble Shooting has been successful in training people to increase their problem-solving capabilities and to communicate readily with persons in other areas and on different levels. (AG)

  6. U.S. forms uranium enrichment corporation

    International Nuclear Information System (INIS)

    After almost 40 years of operation, the federal government is withdrawing from the uranium enrichment business. On July 1, the Department of Energy turned over to a new government-owned entity--the US Enrichment Corp. (USEC)--both the DOE enrichment plants at Paducah, Ky., and Portsmouth, Ohio, and domestic and international marketing of enriched uranium from them. Pushed by the inability of DOE's enrichment operations to meet foreign competition, Congress established USEC under the National Energy Policy Act of 1992, envisioning the new corporation as the first step to full privatization. With gross revenues of $1.5 billion in fiscal 1992, USEC would rank 275th on the Fortune 500 list of top US companies. USEC will lease from DOE the Paducah and Portsmouth facilities, built in the early 1950s, which use the gaseous diffusion process for uranium enrichment. USEC's stock is held by the US Treasury, to which it will pay annual dividends. Martin Marietta Energy Systems, which has operated Paducah since 1984 and Portsmouth since 1986 for DOE, will continue to operate both plants for USEC. Closing one of the two facilities will be studied, especially in light of a 40% world surplus of capacity over demand. USEC also will consider other nuclear-fuel-related ventures. USEC will produce only low-enriched uranium, not weapons-grade material. Indeed, USEC will implement a contract now being completed under which the US will purchase weapons-grade uranium from dismantled Russian nuclear weapons and convert it into low-enriched uranium for power reactor fuel

  7. Production of lutein-enriched microalgal biomass

    OpenAIRE

    Mogedas, B.; Forján, E.; Cuaresma, M.; Garbayo, I.; Vega, J.M.; Vílchez, C.

    2009-01-01

    An integrated approach towards production of lutein-enriched biomass of Chlamydomonas acidophile, an extremophile microalga isolated by our group from Tinto river (Huelva, Spain) was carried out. That approach included determining optimal growth conditions, determining optimal lutein biosynthesis conditions and designing a continuous lutein-enriched biomass production process in a suitable, specifically designed, panel photobioreactor. Optimal growth of the extremophile microalga was found t...

  8. Modeling of Transients in an Enrichment Circuit

    International Nuclear Information System (INIS)

    In the present work a mathematical model is presented in order to describe the dynamic behavior inside a closed enrichment loop, the latter representing a single stage of an uranium gaseous diffusion enrichment cascade.The analytical model is turned into a numerical model, and implemented through a computational code.Transients of two species separation were numerically analyzed, including setting times of each magnitude, behavior of each one of them during different transients, and redistribution of concentrations along the closed loop

  9. Anti-craving effects of environmental enrichment

    OpenAIRE

    Thiel, Kenneth J; Sanabria, Federico; Pentkowski, Nathan S; Neisewander, Janet L.

    2009-01-01

    We hypothesized that environmental enrichment in rats may reduce cocaine-seeking behaviour elicited by cocaine-priming injections and by cocaine-associated cues. Rats trained to self-administer cocaine while housed in isolated conditions were then assigned to live in isolation or an enriched environment for 21 d of forced abstinence. Subsequently, extinction and reinstatement of cocaine-seeking behaviour (operant responses without cocaine available) were assessed. Expt 1 showed that enrichmen...

  10. Uranium enrichment activities: the SILVA project

    International Nuclear Information System (INIS)

    In the general frame of a long term R and D uranium enrichment approach, the French laser isotope separation program (SILVA) is presented including fundamentals of the process, an overview of its organization and activities. The main areas of basic research, subsystems assessment, enrichment demonstrations and plant design are described. The general schedule leading to a future commercial plant is outlined. 11 refs., 7 figs

  11. Environmental enrichment for neotropical primates in captivity

    OpenAIRE

    Boere Vanner

    2001-01-01

    Captivity is an extreme non-natural environment for primates. The success of a breeding colony depends of management and veterinarian procedures which must rely on the knowledge of primates' behavioral needs. Environmental enrichment consists of a series of procedures that improve the quality of life of captive animals by meeting their ethological needs. Enrichment can reduce stress, while increasing animal well being in captivity. Suitable ethical conditions, incidences of behavioral disorde...

  12. Enrichment Discrimination Behavior in Spontaneously Hypertensive Rats

    OpenAIRE

    Ramiz M. Salimov; Kovalev, Georgy I.

    2012-01-01

    Objectives: 1) To reveal, among spontaneously hypertensive rats, subpopulations that diverge in attention to objects enriching an empty cross-maze; 2) To evaluate effect of clinically efficient drug for treatment of attention deficiency atomoxetine on the attention to environmental cues in attentionally-low rats. Method: A novel paradigm that provides measure of attention towards enriching objects independent of general locomotor activity and spatial orientation is employed. The apparatus con...

  13. Principles and techniques of uranium enrichment

    International Nuclear Information System (INIS)

    The main separation processes already used industrially or likely to be used before the end of century (gas diffusion, ultracentrifugation, laser, the nozzle process, a process developed in South Africa) are presented. Some data on the costs of the enrichment are clarified. The main characteristics of the enrichment market in which the Eurodif plant is called upon, on the expiration of five years, to take a foremost place are reported

  14. Uranium enrichment - market, supply, commercial aspects

    International Nuclear Information System (INIS)

    The enrichment market to the end of the century is considered and related to likely variations in the installed nuclear power capacity and in other major assumptions. Particular attention is paid to uranium supply and demand because of its key influence on the long-term development of nuclear power. Enrichment supply and demand up to the mid 1980's is examined in relation to the published plans of the existing suppliers. Urenco terms for the supply of separative work are discussed. (author)

  15. Enrichment of Auxotrophic Mutants in Streptomyces griseus

    OpenAIRE

    Werner, Rolf G.; Arnold L. Demain

    1980-01-01

    A method for the isolation and enrichment of tryptophan auxotrophic mutants of the indolmycin-producing strain Streptomyces griseus ATCC 12648 was developed, using penicillin selection. With UV irradiation of 2.2 × 104 ?W cm?2, a mutation rate to tryptophan auxotrophy of 5.6 × 10?4 was achieved. With 300 ?g ml?1 of penicillin G, an enrichment of tryptophan auxotrophs of about 1,000-fold was attained. Approximately 40% of all survivors were tryptophan auxotrophs.

  16. Compared economic features of enrichment processes

    International Nuclear Information System (INIS)

    Several attempts made in the past have shown that comparing economic features of enrichment processes is a difficult endeavour. The separative work cost concept can be used as a guiding criteria, but other aspects are also important. Dealing solely with enrichment costs leads to qualify the various items which appear in the cost breakdowns of separative work delivered by various enrichment processes. Among these items, a broad distinction can be made between intrinsic characteristics of the processes (i.e. component sophistication, operating staff, energy consumption, material hold-up, etc.) and economic features or assumptions of a more general nature (costs of manpower; rates of return, energy, inflation, etc.). The paper briefly reviews these various aspects and points out some of the difficulties met in attempting comparisons: for instance, the processes under survey rarely attain the same state of development and the general economic backgrounds vary from one country to another. Moreover, differences appear when coping with a real plant project instead of a simple didactic exercise. Although it can hardly be quantified, the ability of the project's sponsoring team then becomes of prime importance. The conclusion of this short paper can only be expressed in very cautious terms. Attaining low enrichment costs is undoubtedly a stimulating challenge which every enrichment producer keeps in mind. But there are many ways to attain or maintain competitivity. Beyond such endeavours, one may simply express the wish to see fair pricing applied within a large and healthy enrichment market. (author). 2 figs, 1 tab

  17. Urine culture

    Science.gov (United States)

    Culture and sensitivity - urine ... sample will be collected as a clean catch urine sample in your health care provider's office or ... will use a special kit to collect the urine. A urine sample can also be taken by ...

  18. Blood culture

    Science.gov (United States)

    Culture - blood ... A blood sample is needed. The site where blood will be drawn is first cleaned with an antiseptic such ... organism from the skin getting into (contaminating) the blood sample and causing a false-positive result (see ...

  19. Enrichment determination of low-enriched uranium material by gamma spectroscopic method

    International Nuclear Information System (INIS)

    In this work the non -destructive gamma spectroscopic method for determination of uranium enrichment is presented. In order to determine the uranium enrichment the activity ratios of 234U/235U and 238U/235U were measured. The activity ratios 234U/235U and 238U/235U were determined by using intrinsic efficiency calibration. As a test of this method, low-enriched uranium standard was measured, the obtained result was in good agreement with the estimated value. (author)

  20. Anaerobic degradation of propane and butane by sulfate-reducing bacteria enriched from marine hydrocarbon cold seeps.

    Science.gov (United States)

    Jaekel, Ulrike; Musat, Niculina; Adam, Birgit; Kuypers, Marcel; Grundmann, Olav; Musat, Florin

    2013-05-01

    The short-chain, non-methane hydrocarbons propane and butane can contribute significantly to the carbon and sulfur cycles in marine environments affected by oil or natural gas seepage. In the present study, we enriched and identified novel propane and butane-degrading sulfate reducers from marine oil and gas cold seeps in the Gulf of Mexico and Hydrate Ridge. The enrichment cultures obtained were able to degrade simultaneously propane and butane, but not other gaseous alkanes. They were cold-adapted, showing highest sulfate-reduction rates between 16 and 20?°C. Analysis of 16S rRNA gene libraries, followed by whole-cell hybridizations with sequence-specific oligonucleotide probes showed that each enrichment culture was dominated by a unique phylotype affiliated with the Desulfosarcina-Desulfococcus cluster within the Deltaproteobacteria. These phylotypes formed a distinct phylogenetic cluster of propane and butane degraders, including sequences from environments associated with hydrocarbon seeps. Incubations with (13)C-labeled substrates, hybridizations with sequence-specific probes and nanoSIMS analyses showed that cells of the dominant phylotypes were the first to become enriched in (13)C, demonstrating that they were directly involved in hydrocarbon degradation. Furthermore, using the nanoSIMS data, carbon assimilation rates were calculated for the dominant cells in each enrichment culture. PMID:23254512

  1. ”Intensive culture

    DEFF Research Database (Denmark)

    Michelsen, Anders Ib

    2012-01-01

    Scott Lash argumenterer i bogen Intensive Culture for en vending fra ”ekstensiv” til ”intensiv” i den nutidige globalisering. Bogens udgangspunkt er en stadig mere ekstensiv og gennemtrængende globalisering af kultur, forbrugs- og vareformer, ”comtemporary culture, today’s capitalism – our global information society – is ever more extensive”. Dette medfører imidlertid et paradoks, fordi den ekstensive kultur slår om i intensive kulturformer: ”Given this growing extensification of contemporary cu...

  2. Organ culture

    DEFF Research Database (Denmark)

    Alm, Rikard; Edvinsson, Lars; Malmsjö, Malin

    2002-01-01

    BACKGROUND: Endothelium dysfunction is believed to play a role in the development of cardiovascular disease. The aim of the present study was to evaluate the suitability of organ culture as a model for endothelium dysfunction. METHODS: The isometric tension was recorded in isolated segments of the rat mesenteric artery branch, before and after organ culture for 20 h. Vasodilatation was expressed as % of preconstriction with U46619. The acetylcholine (ACh) induced nitric oxide (NO) mediated dilat...

  3. Cultural Usability

    DEFF Research Database (Denmark)

    Shi, Qingxin

    2007-01-01

    Culture has already played an important role in the global market. It not only affects products, but also impacts on usability evaluation methods. This project aims to examine in the established thinking aloud usability evaluation method (TA UEM), how does the evaluator build a supportive relationship and communicate effectively with the user in order to find relevant usability problems in culturally localized applications. It includes three parts, pilot study, field study and experiments, to ge...

  4. Separable Bilayer Microfiltration Device for Viable Label-free Enrichment of Circulating Tumour Cells

    Science.gov (United States)

    Zhou, Ming-Da; Hao, Sijie; Williams, Anthony J.; Harouaka, Ramdane A.; Schrand, Brett; Rawal, Siddarth; Ao, Zheng; Brennaman, Randall; Gilboa, Eli; Lu, Bo; Wang, Shuwen; Zhu, Jiyue; Datar, Ram; Cote, Richard; Tai, Yu-Chong; Zheng, Si-Yang

    2014-12-01

    The analysis of circulating tumour cells (CTCs) in cancer patients could provide important information for therapeutic management. Enrichment of viable CTCs could permit performance of functional analyses on CTCs to broaden understanding of metastatic disease. However, this has not been widely accomplished. Addressing this challenge, we present a separable bilayer (SB) microfilter for viable size-based CTC capture. Unlike other single-layer CTC microfilters, the precise gap between the two layers and the architecture of pore alignment result in drastic reduction in mechanical stress on CTCs, capturing them viably. Using multiple cancer cell lines spiked in healthy donor blood, the SB microfilter demonstrated high capture efficiency (78-83%), high retention of cell viability (71-74%), high tumour cell enrichment against leukocytes (1.7-2 × 103), and widespread ability to establish cultures post-capture (100% of cell lines tested). In a metastatic mouse model, SB microfilters successfully enriched viable mouse CTCs from 0.4-0.6 mL whole mouse blood samples and established in vitro cultures for further genetic and functional analysis. Our preliminary studies reflect the efficacy of the SB microfilter device to efficiently and reliably enrich viable CTCs in animal model studies, constituting an exciting technology for new insights in cancer research.

  5. Separable Bilayer Microfiltration Device for Viable Label-free Enrichment of Circulating Tumour Cells

    Science.gov (United States)

    Zhou, Ming-Da; Hao, Sijie; Williams, Anthony J.; Harouaka, Ramdane A.; Schrand, Brett; Rawal, Siddarth; Ao, Zheng; Brennaman, Randall; Gilboa, Eli; Lu, Bo; Wang, Shuwen; Zhu, Jiyue; Datar, Ram; Cote, Richard; Tai, Yu-Chong; Zheng, Si-Yang

    2014-01-01

    The analysis of circulating tumour cells (CTCs) in cancer patients could provide important information for therapeutic management. Enrichment of viable CTCs could permit performance of functional analyses on CTCs to broaden understanding of metastatic disease. However, this has not been widely accomplished. Addressing this challenge, we present a separable bilayer (SB) microfilter for viable size-based CTC capture. Unlike other single-layer CTC microfilters, the precise gap between the two layers and the architecture of pore alignment result in drastic reduction in mechanical stress on CTCs, capturing them viably. Using multiple cancer cell lines spiked in healthy donor blood, the SB microfilter demonstrated high capture efficiency (78–83%), high retention of cell viability (71–74%), high tumour cell enrichment against leukocytes (1.7–2 × 103), and widespread ability to establish cultures post-capture (100% of cell lines tested). In a metastatic mouse model, SB microfilters successfully enriched viable mouse CTCs from 0.4–0.6?mL whole mouse blood samples and established in vitro cultures for further genetic and functional analysis. Our preliminary studies reflect the efficacy of the SB microfilter device to efficiently and reliably enrich viable CTCs in animal model studies, constituting an exciting technology for new insights in cancer research. PMID:25487434

  6. Effect of Sample Pre-enrichment and Characters of Food Samples on the Examination for the Salmonella by Plate Count Method and Fluorescent in-situ Hybridization Technique

    Directory of Open Access Journals (Sweden)

    R.M.U.S.K. Rathnayaka

    2011-01-01

    Full Text Available In most of the novel and traditional methods used in the examination of food samples for Salmonella, pre-enrichment of samples is used as a means of increasing the sensitivity and reliability. However, the influence of pre-enrichment of sample on some of those methods has not been studied. Furthermore, the effect of the conditions of the sample on the sensitivity of some of those methods are also not been studied. The aim of this research was to study the influence of pre-enrichment and the conditions of the samples on the detection sensitivity of one novel method Fluorescent in-situ Hybridization (FISH and one traditional culture techniques (XLT-4 agar plates. To study the influence of enrichment, 60 pork sausage samples collected from 20 different food outlets were examined for Salmonella contamination by both methods with and without pre-enrichment. To study the effect of the conditions of food, collected samples were spiked with 107 cfu mL-1 Salmonella enterica culture and examined with and without pre-enrichment. Detection sensitivity of both methods was higher in pre-enriched fresh samples as well as spiked samples. FISH method was found to be more sensitive and less affected by the conditions of food, compared to culture method.

  7. Isolation and Enrichment of Mouse Female Germ Line Stem Cells

    Directory of Open Access Journals (Sweden)

    Somayeh Khosravi-Farsani

    2015-01-01

    Full Text Available Objective: The existence of female germ-line stem cells (FGSCs has been the subject of a wide range of recent studies. Successful isolation and culture of FGSCs could facilitate studies on regenerative medicine and infertility treatments in the near future. Our aim in the present study was evaluation of the most commonly used techniques in enrichment of FGSCs and in establishment of the best procedure. Materials and Methods: In this experimental study, after digesting neonate ovary from C57Bl/6 mice, we performed 2 different isolation experiments: magnetic activated cell sorting (MACS and pre-plating. MACS was applied using two different antibodies against mouse vasa homolog (MVH and stage-specific embryonic antigen-1 (SSEA1 markers. After the cells were passaged and proliferated in vitro, colony-forming cells were characterized using reverse transcription-polymerase chain reaction (RT-PCR (for analysis of expression of Oct4, Nanog, C-kit, Fragilis, Mvh, Dazl, Scp3 and Zp3, alkaline phosphatase (AP activity test and immunocytochemistry. Results: Data showed that colonies can be seen more frequently in pre-plating technique than that in MACS. Using the SSEA1 antibody with MACS, 1.98 ± 0.49% (Mean ± SDV positive cells were yield as compared to the total cells sorted. The colonies formed after pre-plating expressed pluripotency and germ stem cell markers (Oct4, Nanog, C-kit, Fragilis, Mvh and Dazl whereas did not express Zp3 and Scp3 at the mRNA level. Immunocytochemistry in these colonies further confirmed the presence of OCT4 and MVH proteins, and AP activity measured by AP-kit showed positive reaction. Conclusion: We established a simple and an efficient pre-plating technique to culture and to enrich FGSCs from neonatal mouse ovaries.

  8. Academic Culture and Campus Culture of Universities

    OpenAIRE

    Xi Shen; Xianghong Tian

    2012-01-01

    Academic culture of universities mainly consists of academic outlooks, academic spirits, academic ethics and academic environments. Campus culture in a university is characterized by individuality, academic feature, opening, leading, variety and creativity. The academic culture enhances the construction of campus culture. The campus culture conditions and restricts the development of academic culture. The construction strategies of academic culture and campus culture are as follows: universit...

  9. Evaluation and comparison of rapid methods for the detection of Salmonella in naturally contaminated pine nuts using different pre enrichment media.

    Science.gov (United States)

    Wang, Hua; Gill, Vikas S; Cheng, Chorng-Ming; Gonzalez-Escalona, Narjol; Irvin, Kari A; Zheng, Jie; Bell, Rebecca L; Jacobson, Andrew P; Hammack, Thomas S

    2015-04-01

    Foodborne outbreaks, involving pine nuts and peanut butter, illustrate the need to rapidly detect Salmonella in low moisture foods. However, the current Bacteriological Analytical Manual (BAM) culture method for Salmonella, using lactose broth (LB) as a pre enrichment medium, has not reliably supported real-time quantitative PCR (qPCR) assays for certain foods. We evaluated two qPCR assays in LB and four other pre enrichment media: buffered peptone water (BPW), modified BPW (mBPW), Universal Pre enrichment broth (UPB), and BAX(®) MP media to detect Salmonella in naturally-contaminated pine nuts (2011 outbreak). A four-way comparison among culture method, Pathatrix(®) Auto, VIDAS(®) Easy SLM, and qPCR was conducted. Automated DNA extraction techniques were compared with manual extraction methods (boiling or InstaGene™). There were no significant differences (P > 0.05) among the five pre enrichment media for pine nuts using the culture method. While both qPCR assays produced significantly (P ? 0.05) higher false negatives in 24 h pre enriched LB than in the other four media, they were as sensitive as the culture method in BPW, mBPW, UPB, and BAX media. The VIDAS Easy and qPCR were equivalent; Pathatrix was the least effective method. The Automatic PrepSEQ™ DNA extraction, using 1000 ?L of pre enrichment, was as effective as manual extraction methods. PMID:25475267

  10. Cultural Robotics: The Culture of Robotics and Robotics in Culture

    OpenAIRE

    Hooman Samani; Elham Saadatian; Natalie Pang; Doros Polydorou; Owen Noel Newton Fernando; Ryohei Nakatsu; Jeffrey Tzu Kwan Valino Koh

    2013-01-01

    In this paper, we have investigated the concept of "Cultural Robotics" with regard to the evolution of social into cultural robots in the 21st Century. By defining the concept of culture, the potential development of a culture between humans and robots is explored. Based on the cultural values of the robotics developers, and the learning ability of current robots, cultural attributes in this regard are in the process of being formed, which would define the new concept of cultural robotics. Ac...

  11. A protocol for isolation and enriched monolayer cultivation of neural precursor cells from mouse dentate gyrus

    OpenAIRE

    GerdKempermann; HarishBabu; Jan-HendrikClaasen

    2011-01-01

    In vitro assays are valuable tools to study the characteristics of adult neural precursor cells under controlled conditions with a defined set of parameters. We here present a detailed protocol based on our previous original publication (Babu et al., Enriched monolayer precursor cell cultures from micro-dissected adult mouse dentate gyrus yield functional granule cell-like neurons, PLoS One 2007, 2:e388) to isolate neural precursor cells from the hippocampus of adult mice and maintain and pro...

  12. Populations Implicated in Anaerobic Reductive Dechlorination of 1,2-Dichloropropane in Highly Enriched Bacterial Communities†

    OpenAIRE

    Ritalahti, Kirsti M; Löffler, Frank E

    2004-01-01

    1,2-Dichloropropane (1,2-D), a widespread groundwater contaminant, can be reductively dechlorinated to propene by anaerobic bacteria. To shed light on the populations involved in the detoxification process, a comprehensive 16S rRNA gene-based bacterial community analysis of two enrichment cultures derived from geographically distinct locations was performed. Analysis of terminal restriction fragments, amplicons obtained with dechlorinator-specific PCR primers, and enumeration with quantitativ...

  13. Enrichment of microbial community generating electricity using a fuel-cell-type electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.H.; Kim, G.T.; Chang, I.S.; Lee, J.; Phung, N.T. [Water Environment and Remediation Research Center, Korea Inst. of Science and Technology, Seoul (Korea); Park, H.S. [Water Environment and Remediation Research Center, Korea Inst. of Science and Technology, Seoul (Korea); Samsung Engineering R and D Center, Yongin-Si (Korea); Kim, H.J. [Water Environment and Remediation Research Center, Korea Inst. of Science and Technology, Seoul (Korea); Korea BioSystems Co. (Korea)

    2004-07-01

    A fuel cell was used to enrich a microbial consortium generating electricity, using organic wastewater as the fuel. Within 30 days of enrichment the maximum current of 0.2 mA was generated with a resistance of 1 k{omega}. Current generation was coupled to a fall in chemical oxygen demand from over 1,700 mg 1{sup -1} down to 50 mg 1{sup -1}. Denaturing gradient gel electrophoresis showed a different microbial population in the enriched electrode from that in the sludge used as the inoculum. Electron microscopic observation showed a biofilm on the electrode surface and microbial clumps. Nanobacteria-like particles were present on the biofilm surface. Metabolic inhibitors and electron acceptors inhibited the current generation. 16S ribosomal RNA gene analysis showed a diverse bacterial population in the enrichment culture. These findings demonstrate that an electricity-generating microbial consortium can be enriched using a fuel cell and that the electrochemical activity is a form of anaerobic electron transfer. (orig.)

  14. Enrichment of anaerobic syngas-converting bacteria from thermophilic bioreactor sludge

    OpenAIRE

    Joana I. Alves; Stams, Alfons J M; Plugge, Caroline M.; M. Madalena Alves; Sousa, Diana Z.

    2013-01-01

    Thermophilic (55 °C) anaerobic microbial communities were enriched with a synthetic syngas mixture (composed of CO, H2, and CO2) or with CO alone. Cultures T-Syn and T-CO were incubated and successively transferred with syngas (16 transfers) or CO (9 transfers), respectively, with increasing CO partial pressures from 0.09 to 0.88 bar. Culture T-Syn, after 4 successive transfers with syngas, was also incubated with CO and subsequently transferred (9 transfers) with solely this substrate – cult...

  15. Enhanced biosynthetically directed fractional carbon-13 enrichment of proteins for backbone NMR assignments.

    Science.gov (United States)

    Wenrich, Broc R; Sonstrom, Reilly E; Gupta, Riju A; Rovnyak, David

    2015-11-01

    Routes to carbon-13 enrichment of bacterially expressed proteins include achieving uniform or positionally selective (e.g. ILV-Me, or (13)C', etc.) enrichment. We consider the potential for biosynthetically directed fractional enrichment (e.g. carbon-13 incorporation in the protein less than 100%) for performing routine n-(D)dimensional NMR spectroscopy of proteins. First, we demonstrate an approach to fractional isotope addition where the initial growth media containing natural abundance glucose is replenished at induction with a small amount (e.g. 10%(w/w)u-(13)C-glucose) of enriched nutrient. The approach considered here is to add 10% (e.g. 200mg for a 2g/L culture) u-(13)C-glucose at the induction time (OD600=0.8), resulting in a protein with enhanced (13)C incorporation that gives almost the same NMR signal levels as an exact 20% (13)C sample. Second, whereas fractional enrichment is used for obtaining stereospecific methyl assignments, we find that (13)C incorporation levels no greater than 20%(w/w) yield (13)C and (13)C-(13)C spin pair incorporation sufficient to conduct typical 3D-bioNMR backbone experiments on moderate instrumentation (600MHz, RT probe). Typical 3D-bioNMR experiments of a fractionally enriched protein yield expected backbone connectivities, and did not show amino acid biases in this work, with one exception. When adding 10% u-(13)C glucose to expression media at induction, there is poor preservation of (13)C?-(13)C? spin pairs in the amino acids ILV, leading to the absence of C? signals in HNCACB spectra for ILV, a potentially useful editing effect. Enhanced fractional carbon-13 enrichment provides lower-cost routes to high throughput protein NMR studies, and makes modern protein NMR more cost-accessible. PMID:26256059

  16. Culturally Responsive Teaching: Understanding Disability Culture

    Science.gov (United States)

    Darrow, Alice-Ann

    2013-01-01

    To be culturally responsive teachers, we must first have an understanding of other cultures and how students from these cultures differ from one another. As we consider the many cultures represented in our classrooms, we might also consider students with disabilities as a cultural group. Within any main culture are subgroups differentiated by…

  17. A comparison of two enrichment and two plating media for the isolation of Salmonella sp. from broilers.

    OpenAIRE

    Truscott, R.B.

    1983-01-01

    Twenty duplicate cloacal swabs and the intestines of 98 broilers were cultured using Rappaport-Vassiliadis and tetrathionate as enrichment broths. These were plated to brilliant green and modified dulcitol brilliant green agars at one, two and seven days. Salmonellae were recovered with greater frequency from tetrathionate plated to modified dulcitol brilliant green than the other combinations.

  18. Biblioteca Na?ional? a României: obiective ?i perspective în valorificarea patrimoniului cultural

    Directory of Open Access Journals (Sweden)

    Elena Tîrziman

    2008-01-01

    Biblioteca Na?ional? a României este implicat? în proiecte interna?ionale care au ca scop crearea de con?inut digital relevant pentru memoria cultural? european?: The European Library – TEL (Biblioteca european?, Manuscriptorium ?i ENRICH – European Networking Resources and Information concerning Cultural Heritage, proiecte coordonate de Biblioteca Na?ional? a Cehiei. Biblioteca Na?ional? a României a contribuit la proiectele Manuscriptorium / ENRICH prin carte româneasc? veche din perioada corespunz?toare secolelor XVI-XVII.

  19. Is «cultural tourism» actually «cultural»?

    Directory of Open Access Journals (Sweden)

    David Senabre López

    2007-09-01

    Full Text Available The epithet of cultural has been used as an adulterated attraction for a kind of leisure activity dressed up in all its finery: the type of tourism that is linked to the historic heritage. The tourism client sets off for an apparent happiness by means of a manipulated, abridged or smoothen by-product of a civilisation’s real historic essence, without paying any attention to –or passively assumin– the mercantilist machinery that it is part of. The label of «cultural» is often distorted by the superficial made of it.Should other forms of tourism that do not involve heritage –such as beach holi- days, rural tourism or mountain holidays– be considered as ‘a-cultural’? Can anybody acquire any culture just by travelling or culture is something that must be carried on by the traveller so as to properly value what he sees? Surveys on cultural tourism so far have concentrated on boosting its efficiency from a business point of view –which is a wrong approach– instead of analysing the phenomenon from a humanistic perspective. Key words: Tourism, Cultura, Leisure, Heritage.

  20. Microscale Generation of Cardiospheres Promotes Robust Enrichment of Cardiomyocytes Derived from Human Pluripotent Stem Cells

    Directory of Open Access Journals (Sweden)

    Doan C. Nguyen

    2014-08-01

    Full Text Available Cardiomyocytes derived from human pluripotent stem cells (hPSCs are a promising cell source for regenerative medicine, disease modeling, and drug discovery, all of which require enriched cardiomyocytes, ideally ones with mature phenotypes. However, current methods are typically performed in 2D environments that produce immature cardiomyocytes within heterogeneous populations. Here, we generated 3D aggregates of cardiomyocytes (cardiospheres from 2D differentiation cultures of hPSCs using microscale technology and rotary orbital suspension culture. Nearly 100% of the cardiospheres showed spontaneous contractility and synchronous intracellular calcium transients. Strikingly, from starting heterogeneous populations containing ?10%–40% cardiomyocytes, the cell population within the generated cardiospheres featured ?80%–100% cardiomyocytes, corresponding to an enrichment factor of up to 7-fold. Furthermore, cardiomyocytes from cardiospheres exhibited enhanced structural maturation in comparison with those from a parallel 2D culture. Thus, generation of cardiospheres represents a simple and robust method for enrichment of cardiomyocytes in microtissues that have the potential use in regenerative medicine as well as other applications.

  1. Enrichment of anammox bacteria fro marine environment for the construction of a bioremediation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Jun; Sakka, Makiko; Kimura, Tetsuya; Sakka, Kazuo [Mie Univ., Tsu (Japan). Graduate School of Bioresources; Furukawa, Kenji [Kumamoto Univ. (Japan). Dept. of Civil Engineering and Architecture

    2008-01-15

    In the global ocean nitrogen cycle, the anaerobic ammonium-oxidizing (anammox) process is recognized as important. In this study, we established an enrichment culture of marine anammox bacteria (MAB) in a column-type reactor. The reactor, which included a porous polyester non-woven fabric that had been placed at the sea floor in advance for enrichment, was continuously fed with NH{sub 4}Cl and NaNO{sub 2} for more than 1 year. Anammox activity in the MAB reactor was confirmed by {sup 15}N tracer analysis using {sup 15}NH{sub 4}Cl and Na{sup 14}NO{sub 2}. We identified two 16S rRNA genes in the amplified DNA fragments derived from MAB, which were highly homologous with those from Candidatus ''Scalindua wagneri'' and an uncultured planctomycete clone. Fluorescence in situ hybridization analysis using an anammox-specific probe also confirmed that MAB predominated in the reactor. To our knowledge, this is the first report on the establishment of an enrichment culture of anammox bacteria from the marine environment using a continuous culture system. (orig.)

  2. On the Cultural Differences in Tourism Translation

    Directory of Open Access Journals (Sweden)

    Lihua YANG

    2014-03-01

    Full Text Available With the rapid development of tourism industry in China, it is urgent to translate tourist text from Chinese into English. Translation is not a simple mechanic linguistic transference, but involves complex cross-cultural communication. English and Chinese have different cultures, so translator must pay attention to the cultural differences between the two languages for successful cross-cultural communication. A good tourist text will arouse potential readers’ interest in the scenic spots, which will help both the development of Chinese tourist industry, and the output of Chinese culture and the enrichment of the target culture. The paper makes an analysis of cultural differences between east and west from the aspect of thinking mode, historical background, and religion and speech rhetoric. Then, it studies the function of tourism text as well as some translation principles and methods, including rewriting, adding and cutting. In the conclusion, the author emphasizes that translators should not only lay solid linguistic foundation, but also pay attention to the cultural factors in both English and Chinese for the successful cross-cultural communication.

  3. High-rate biological denitrification in the cyclic rotating-bed biological reactor: Effect of COD/NO3(-), nitrate concentration and salinity and the phylogenetic analysis of denitrifiers.

    Science.gov (United States)

    Jafari, Seyed Javad; Moussavi, Gholamreza; Yaghmaeian, Kamyar

    2015-12-01

    The effects of COD/NO3(-) ratio, nitrate concentration and salinity was tested on the performance of the CRBR in denitrification with catechol as carbon source. The maximum nitrate reduction attained at COD/NO3(-) ratio of 1. The CRBR operated at optimum COD/NO3(-) ratio could completely denitrify the nitrate at inlet concentration up to 1250mg/L without nitrite accumulation. The maximum denitrification rate in the CRBR was 3.56kgNO3(-)/m(3)d with a nitrate reduction efficiency of 99% when the bioreactor was operated at inlet nitrate loading rate of 3.6kgNO3(-)/m(3)d. The denitrification performance of the CRBR was not affected significantly by NaCl concentrations up to 20g/L. 16S rRNA fragment and phylogenetic analysis identified Pseudomonas resinovorans, Stenotrophomonas maltophilia and Bacillus cereus as the most abundant denitrifiers in biomass. Accordingly, the CRBR is a high-rate bioreactor and appropriate technology for treatment of nitrate-laden industrial wastewaters containing phenolic compounds and salinity. PMID:26369277

  4. Comparison of analytical values for enrichment nutrients in selected grain products to federal enrichment standards

    Science.gov (United States)

    Enriched grain products are required to have iron, thiamin, riboflavin, niacin, and folic acid added at specified levels (minimum and maximum) according to the U.S. Code of Federal Regulations (CFR). To provide up-to-date values for the USDA National Nutrient Database for Standard Reference, enriche...

  5. Linking nutrient enrichment, sediment erodibility and biofilms

    Science.gov (United States)

    Conrad, B.; Mahon, R.; Sojka, S. L.

    2014-12-01

    Sediment movement in coastal lagoons affects nutrient flux and primary producer growth. Previous research has shown that sediment erodibility is affected by biofilm concentration and that growth of benthic organisms, which produce biofilm, is affected by nutrient enrichment. However, researchers have not examined possible links between nutrient addition and sediment erodibility. We manipulated nutrient levels in the water column of 16 microcosms filled with homogenized sediment from a shallow coastal lagoon and artificial seawater to determine the effects on biofilm growth, measured through chlorophyll a and colloidal carbohydrate concentrations. Erosion tests using a Gust microcosm were conducted to determine the relationship between sediment erodibility and biofilm concentration. Results show that carbohydrate levels decreased with increasing nutrient enrichment and were unrelated to chlorophyll concentrations and erodibility. The nutrient levels did not predictably affect the chlorophyll levels, with lower chlorophyll concentrations in the control and medium enrichment treatments than the low and high enrichment treatments. Controls on biofilm growth are still unclear and the assumed relationship between carbohydrates and erodibility may be invalid. Understanding how biofilms respond to nutrient enrichment and subsequent effects on sediment erodibility is essential for protecting and restoring shallow coastal systems.

  6. The enriched chromium neutrino source for GALLEX

    International Nuclear Information System (INIS)

    The preparation and study of an intense source of neutrinos in the form of neutron irradiated materials which are enriched in Cr-50 for use in the GALLEX solar neutrino experiment are discussed. Chromyl fluoride gas is enriched in the Cr-50 isotope by gas centrifugation and subsequently converted to a very stable form of chromium oxide. The results of neutron activation analyses of such chromium samples indicate low levels of any long-lived activities, but show that short-lived activities, in particular Na-24, may be of concern. These results show that irradiating chromium oxide enriched in Cr-50 is preferable to irradiating either natural chromium or argon gas as a means of producing a neutrino source to calibrate the GALLEX detector. These results of the impurity level analysis of the enriched chromyl fluoride gas and its conversion to the oxide are also of interest to work in progress by other members of the Collaboration investigating an alternative conversion of the enriched gas to chromium metal. 35 refs., 12 figs., 5 tabs

  7. Uranium enrichment: Supply, demand and costs

    International Nuclear Information System (INIS)

    Most of the proven reactor types envisaged for commercial operation over the next two decades require enriched uranium. Even assuming a larger share for natural uranium fueled heavy water systems and an early date of introduction for breeders on a commercial scale, enriched uranium fueled stations are likely to represent the bulk of the new nuclear capacity to be installed between now and the turn of the century. Hence the problem of ensuring an adequate supply of enrichment services at the lowest possible cost is just as important as that of securing a solid basis of uranium ore reserves. The present enrichment capacity available in the western world is likely to be exhausted in the early 1980's, the exact date depending on the rate of growth of nuclear capacity and on plausible variations in the proportions of different reactor types. Since the lead time between consideration and commissioning of an enrichment plant is of the order of 8 to 10 years, and since the issue has significant national, regional and international aspects on the commercial and political levels, it has recently been in the forefront of interest, and no review of nuclear power prospects would be complete without its consideration

  8. Culture shock

    Directory of Open Access Journals (Sweden)

    Adrian Furham

    2012-01-01

    Full Text Available This paper considers the popular concept of culture shock. From the academic perspective co-researchers from different disciplines (anthropology, education, psychiatry, psychology, sociology have attempted to operationalise the concept and understand the process behind it. It represents fifty years of research using different methodologies and trying to answer different questions about the experience of travel for many reasons. This paper also considers issues concerned with the “overseas” student, of which there are ever more, travelling abroad to study. They can have serious culture shock difficulties. Implications of this research are considered

  9. Geo-neutrinos and Silicate Earth Enrichment

    CERN Document Server

    Dye, Steve

    2010-01-01

    The terrestrial distribution of U, Th, and K abundances governs the thermal evolution, traces the differentiation, and reflects the bulk composition of the earth. Comparing the bulk earth composition to chondritic meteorites estimates the net amounts of these radiogenic heat-producing elements available for partitioning to the crust, mantle, and core. Core formation enriches the abundances of refractory lithophile elements, including U and Th, in the silicate earth by ~1.5. Global removal of volatile elements potentially increases this enrichment to ~2.8. The K content of the silicate earth follows from the ratio of K to U. Variable enrichment produces a range of possible heat-producing element abundances in the silicate earth. A model assesses the essentially fixed amounts of U, Th, and K in the approximately closed crust reservoir. Subtracting these sequestered crustal amounts from the variable amounts in the silicate earth results in a range of possible mantle allocations, leaving global dynamics and therm...

  10. A consideration on laser enrichment module

    International Nuclear Information System (INIS)

    Several problems are discussed for designing a simplified enrichment module based on Atomic Laser Isotope Separation Method, which involve the vaporization of metal, laser excitation, laser ionization and ion recovery. The conditions at which the consumed energy has the minimum value are obtained by calculating the specific energy consumption for producing unit amount of enriched products. It is found that there should be an appropriate relationship between the processing atomic density and the electrode gap in order to avoid the enrichment loss caused by the charge exchange during the ion recovery. Moreover it is also found that this relation depends on the electrode length measured along both the atomic beam direction and the laser beam direction. (author)

  11. Environmental enrichment for neotropical primates in captivity

    Directory of Open Access Journals (Sweden)

    Boere Vanner

    2001-01-01

    Full Text Available Captivity is an extreme non-natural environment for primates. The success of a breeding colony depends of management and veterinarian procedures which must rely on the knowledge of primates' behavioral needs. Environmental enrichment consists of a series of procedures that improve the quality of life of captive animals by meeting their ethological needs. Enrichment can reduce stress, while increasing animal well being in captivity. Suitable ethical conditions, incidences of behavioral disorders, minimal clinical interventions, low mortality, higher reproduction rates and cost/benefit relationship, reflect directly on the quality of captive breeding colonies. Anthropoids like Neotropical primates possess complex neural structures and relate, in a sophisticated manner, to the environment. This review reports important experiences on enrichment procedures for Neotropical primates and the physiological events which could explain improvement of animal well-being.

  12. Uranium enrichment management review: summary of analysis

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    In May 1980, the Assistant Secretary for Resource Applications within the Department of Energy requested that a group of experienced business executives be assembled to review the operation, financing, and management of the uranium enrichment enterprise as a basis for advising the Secretary of Energy. After extensive investigation, analysis, and discussion, the review group presented its findings and recommendations in a report on December 2, 1980. The following pages contain background material on which that final report was based. This report is arranged in chapters that parallel those of the uranium enrichment management review final report - chapters that contain summaries of the review group's discussion and analyses in six areas: management of operations and construction; long-range planning; marketing of enrichment services; financial management; research and development; and general management. Further information, in-depth analysis, and discussion of suggested alternative management practices are provided in five appendices.

  13. Uranium enrichment management review: summary of analysis

    International Nuclear Information System (INIS)

    In May 1980, the Assistant Secretary for Resource Applications within the Department of Energy requested that a group of experienced business executives be assembled to review the operation, financing, and management of the uranium enrichment enterprise as a basis for advising the Secretary of Energy. After extensive investigation, analysis, and discussion, the review group presented its findings and recommendations in a report on December 2, 1980. The following pages contain background material on which that final report was based. This report is arranged in chapters that parallel those of the uranium enrichment management review final report - chapters that contain summaries of the review group's discussion and analyses in six areas: management of operations and construction; long-range planning; marketing of enrichment services; financial management; research and development; and general management. Further information, in-depth analysis, and discussion of suggested alternative management practices are provided in five appendices

  14. Inhomogeneous chemical enrichment in the Galactic Halo

    Science.gov (United States)

    Kobayashi, Chiaki

    2015-08-01

    In a galaxy, chemical enrichment takes place in an inhomogeneous fashion, and the Galactic Halo is one of the places where the inhomogeneous effects are imprinted and can be constrained from observations. I show this using my chemodynamical simulations of Milky Way type galaxies. The scatter in the elemental abundances is originated from radial migration, merging/accretion of satellite galaxies, local variation of star formation and chemical enrichment, and intrinsic variation of nucleosynthesis yields. In the simulated galaxies, there is no strong age-metallicity relations. This means that the most metal poor stars are not always the oldest stars, and can be formed in chemically unevolved clouds at later times. The long-lifetime sources of chemical enrichment such as asymptotic giant blanch stars or neutron star mergers can contribute the abundance patterns of extremely metal-poor stars, which are in good agreement with observations.

  15. Method of deuterium isotope separation and enrichment

    International Nuclear Information System (INIS)

    A method is described for separating and enriching deuterium containing molecules comprising the steps of: providing a source of organic molecules containing a normal abundance of deuterium atoms, the organic molecules having a structural formula RX, in which R is an organic radical selected from ethyl, isopropyl, t-butyl and 3-cyclopentenyl, and in which X is selected from F, Cl, Br and OH, and wherein R represents 3-cyclopentenyl, X may additionally represent H; exposing the molecules to the radiation of at least one pulsed infrared laser source which has been specifically tuned and focussed to selectively decompose RX molecules containing deuterium to form an enriched olefin specie containing deuterium, and HX; and separating the deuterium enriched olefin specie from the undecomposed deuterium depleted RX molecules and HX. (author)

  16. Opening of the industrial period of enrichment

    International Nuclear Information System (INIS)

    The annual value of the world's needs for separative work is quoted to show that uranium enrichment is an industrial reality. Enrichment organisations in which France is concerned are discussed, in particular Eurodif. The financial basis and industrial structure of this multinational body are explained. The importance, to the gaseous diffusion uranium enrichment industry, of raw materials and power is stressed, and the need to consider how the industry fits into the fuel cycle and how it should be related to the production of natural uranium. The policy on commercial activities and contracts with customers is discussed. Plans to construct a second commercial plant under an organisation Coredif (participants: Eurodif, C.E.A. and the atom energy authority of Iran) are described. (U.K.)

  17. Uranium enrichment by centrifuge in Japan

    International Nuclear Information System (INIS)

    The demand for enriched uranium is on the increase with nuclear power capacity in which the LWR predominates and is estimated to exceed the supply from the present facilities in the world in less than ten years. Therefore, the basic strategy for enriched uranium is investigated on the following three-point long-range program in Japan: 1. To continue negotiations to extend the current allocation by the long-term contract; 2. To seek active participation in international enrichment projects; and 3. To make efforts to develop uranium enrichment technology and to construct inland facilities. On this basis, a vigorous development program of gas centrigue process for industrialization was launched out in 1972 as a national project. Ever since substantial progress in this field has been made and development works have been increased year after year. At present, a concrete plan of a pilot plant is taking shape. Up to now, several types of centrifuges were developed, of which some were completed as prototype models, and subjected to life tests and also to extensive earthquake-resistivity tests for the characteristics of Japanese geological condition. An enrichment plant is composed of so many centrifuges that the installation and piping system of centrifuges is an important factor which has an effect on plant economy and reliability. Two types of the experimental cascade were constructed in Japan. One has been in operation since 1973, and the other since 1975. Valuable empirical data have been accumulated on cascade characteristics, maintenance scheme and so on. It will be important for the coming plants to have a flexibility to escalation of labor and energy cost, or to variation of the separative work requirement and further. An economic prospect of centrifuge enrichment process is presented

  18. Enrichment for Plesiomonas shigelloides from stools.

    OpenAIRE

    Rahim, Z.; Kay, B.A.

    1988-01-01

    Bile peptone broth and alkaline peptone water (pH 8.5) were examined as enrichment media for the isolation of Plesiomonas shigelloides from stools, with salmonella-shigella agar as the isolation medium. After 423 parallel examinations in two different experiments, bile peptone broth enrichment for 24 h was observed to be six times more effective (P less than 0.01) than direct plating alone on salmonella-shigella agar. Bile peptone broth was found to be twice as effective as alkaline peptone w...

  19. Comparison of VHTR and ALWR fuel enrichments

    International Nuclear Information System (INIS)

    The higher enrichment of the VHTR relative to the ALWR is mainly due to the much higher specific power and the targeted cycle length of 18 months, which lead to a signficantly higher cycle burnup. If the cycle burnup of the VHTR is made similar to that of the ALWR by reducing the specific power or allowing a shorter cycle length than the targeted value, the targeted discharge burnup could be achieved with fuel enrichment similar to (or slightly higher than) a value required for the ALWR to achieve the same discharge burnup

  20. Uranium enrichment services in the United States

    International Nuclear Information System (INIS)

    The United States of America is the world's largest market for uranium enrichment services. After the disintegration of the Soviet Union, Russian uranium is entering the world market on an increasing scale. The U.S. tries to protect its market and, in this connection, also the European market from excessive price drops by taking anti-dumping measures. In order to become more competitive, American companies have adapted modern enrichment techniques from Europe. European - U.S. joint ventures are to help, also technically and economically, to integrate military uranium, accumulating as a consequence of worldwide disarmament, into the commercial fuel cycle for the peaceful use of nuclear power. (orig.)