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Sample records for denitrifying enrichment cultures

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

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

    The abundance of baroduric, culturable nitrifying and denitrifying bacteria in the deep-sea cores of Central Indian Basin (CIB) at ca 5000 m depth was investigated. Analysis of 8 cores, sampled between 10 degrees 00 minutes S and 75 degrees 55...

  2. Simultaneous enrichment of denitrifying anaerobic methane-oxidizing microorganisms and anammox bacteria in a hollow-fiber membrane biofilm reactor.

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

    2017-01-01

    In this study, the coculture system of denitrifying anaerobic methane oxidation (DAMO) microbes and anaerobic ammonium oxidation (anammox) bacteria was successfully enriched in a hollow-fiber membrane biofilm reactor (HfMBR) using freshwater sediment as the inoculum. The maximal removal rates of nitrate and ammonium were 78 mg N/L/day (131 mg N/m(2)/day) and 26 mg N/L/day (43 mg N/m(2)/day), respectively. Due to the high rate of methane mass transfer in HfMBR, the activity of DAMO archaea continued to increase during the enrichment period, indicating that HfMBR could be a powerful tool to enrich DAMO microorganisms. Effects of partial methane pressure, temperature, and pH on the cocultures were obvious. However, the microbial activity in HfMBR could be recovered quickly after the shock change of environmental factors. Furthermore, the result also found that DAMO bacteria likely had a stronger competitive advantage than anammox bacteria under the operating conditions in this study. High-throughput sequencing 16S rRNA genes illustrated that the dominant microbes were NC10, Euryarchaeota, Proteobacteria, Planctomycetes, and Chlorobi with relative abundance of 38.8, 26.2, 13.78, 6.2, and 3.6 %, respectively.

  3. Operation of three parallel AN/AO processes to enrich denitrifying phosphorus removing bacteria for low strength wastewater treatment

    XIA Si-qing; LIU Hong-bo

    2006-01-01

    Three parallel anaerobic-anoxic/anaerobic-aerobic (AN/AO) processes were developed to enrich denitrifying phosphorus removal bacteria (DPB) for low strength wastewater treatment. The main body of the parallel AN/AO process consists of an AN(anaerobic-anoxic) process and an AO (anaerobic-aerobic) process. In the AO process, the common phosphorus accumulating organisms (PAOs) was dominate, while in the AN process, DPB was dominate. The volume of anaerobic zone(Vana):anoxic zone(Vano):aerobic zone (Vaer) for the parallel AN/AO process is 1:1:1 in contrast with a Vana:Vaer and Vano,:Vaer of 1:2 and 1:4 for a traditional biological nutrient removal process (BNR). Process 3 excels in the 3 processes on the basis of COD, TN and TP removal. For 4 month operation, the effluent COD concentration of process 3 did not exceed 60 mg/L; the effluent TN concentration of process 3 was lower than 15 mg/L; and the effluent TP concentration of process 3 was lower than 1 mg/L.

  4. Isolation and denitrification characteristic of an aerobic denitrifier

    ZHOU Dan-dan; MA Fang; WANG Hong-yu; DONG Shuang-shi; WANG Ai-jie

    2006-01-01

    Aerobic denitrifiers were enriched by activated sludge cultivation method. By this way, 105 strains were isolated from the activated sludge and 25 strains were confirmed to be capable of obtaining energy by deoxidization of nitrate to nitrogen gas under aerobic condition. The characteristic of one denitrifier, Pseudomonas chloritidismutans strain, was particularly studied due to its higher nitrogen removal rate. It was found that Pseudomonas chloritidismutans can use nitrite, nitrate and oxygen for aerobic respiration in liquid medium, and the pH increased and ORP decreased by activated denitrifier. When they used nitrite or nitrate for respiration, nitrogen removal effect was high and nitrite could be reduced more efficiently than nitrate. Denitrification process was accomplished faster when both nitrite and nitrate existed in the medium compared to each of which existed alone. Particularly, at denitrifying activity, the nitrogen removal rate of strain was not affected by the DO concentration in the culture media.

  5. Cultural Enrichment through Community Action.

    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…

  6. 21 CFR 866.2330 - Enriched culture medium.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Enriched culture medium. 866.2330 Section 866.2330...) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2330 Enriched culture medium. (a) Identification. An enriched culture medium is a device that consists primarily of liquid...

  7. Enrichment of high ammonia tolerant methanogenic culture

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

    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...

  8. Anaerobic degradation of long-chain alkylamines by a denitrifying Pseudomonas stutzeri.

    Nguyen, Phuong D; van Ginkel, Cornelis G; Plugge, Caroline M

    2008-10-01

    The anaerobic degradation of tetradecylamine and other long-chain alkylamines by a newly isolated denitrifying bacterium was studied. Strain ZN6 was isolated from a mixture of soil and active sludge and was identified as representing Pseudomonas stutzeri, based on partial 16S rRNA gene sequence analysis. Strain ZN6 was a mesophilic, motile, Gram-negative rod-shaped bacterium and was able to grow on a variety of compounds including even-numbered primary fatty amines with alkyl chains ranging from C(4) to C(18) coupled to nitrate reduction. Alkylamines were used as sole carbon, energy and nitrogen source and were completely mineralized. Nitrate was dissimilated by ZN6 to nitrite. When strain ZN6 was grown under nitrate limitation, nitrite was slowly dissimilated further. When cocultivated with the complete denitrifier Castellaniella defragens ZN3, anaerobic degradation under denitrifying of alkylamines by strain ZN6 was slightly faster. Strain ZN3 is a complete denitrifier, unable to convert tetradecylamine, and was copurified from the same enrichment culture as strain ZN6. The proposed pathway for the degradation of alkylamines in strain ZN6 starts with C-N cleavages to alkanals and further oxidation to the corresponding fatty acids.

  9. Culture enriched molecular profiling of the cystic fibrosis airway microbiome.

    Sibley, Christopher D; Grinwis, Margot E; Field, Tyler R; Eshaghurshan, Christina S; Faria, Monica M; Dowd, Scot E; Parkins, Michael D; Rabin, Harvey R; Surette, Michael G

    2011-01-01

    The microbiome of the respiratory tract, including the nasopharyngeal and oropharyngeal microbiota, is a dynamic community of microorganisms that is highly diverse. The cystic fibrosis (CF) airway microbiome refers to the polymicrobial communities present in the lower airways of CF patients. It is comprised of chronic opportunistic pathogens (such as Pseudomonas aeruginosa) and a variety of organisms derived mostly from the normal microbiota of the upper respiratory tract. The complexity of these communities has been inferred primarily from culture independent molecular profiling. As with most microbial communities it is generally assumed that most of the organisms present are not readily cultured. Our culture collection generated using more extensive cultivation approaches, reveals a more complex microbial community than that obtained by conventional CF culture methods. To directly evaluate the cultivability of the airway microbiome, we examined six samples in depth using culture-enriched molecular profiling which combines culture-based methods with the molecular profiling methods of terminal restriction fragment length polymorphisms and 16S rRNA gene sequencing. We demonstrate that combining culture-dependent and culture-independent approaches enhances the sensitivity of either approach alone. Our techniques were able to cultivate 43 of the 48 families detected by deep sequencing; the five families recovered solely by culture-independent approaches were all present at very low abundance (<0.002% total reads). 46% of the molecular signatures detected by culture from the six patients were only identified in an anaerobic environment, suggesting that a large proportion of the cultured airway community is composed of obligate anaerobes. Most significantly, using 20 growth conditions per specimen, half of which included anaerobic cultivation and extended incubation times we demonstrate that the majority of bacteria present can be cultured.

  10. Culture enriched molecular profiling of the cystic fibrosis airway microbiome.

    Christopher D Sibley

    Full Text Available The microbiome of the respiratory tract, including the nasopharyngeal and oropharyngeal microbiota, is a dynamic community of microorganisms that is highly diverse. The cystic fibrosis (CF airway microbiome refers to the polymicrobial communities present in the lower airways of CF patients. It is comprised of chronic opportunistic pathogens (such as Pseudomonas aeruginosa and a variety of organisms derived mostly from the normal microbiota of the upper respiratory tract. The complexity of these communities has been inferred primarily from culture independent molecular profiling. As with most microbial communities it is generally assumed that most of the organisms present are not readily cultured. Our culture collection generated using more extensive cultivation approaches, reveals a more complex microbial community than that obtained by conventional CF culture methods. To directly evaluate the cultivability of the airway microbiome, we examined six samples in depth using culture-enriched molecular profiling which combines culture-based methods with the molecular profiling methods of terminal restriction fragment length polymorphisms and 16S rRNA gene sequencing. We demonstrate that combining culture-dependent and culture-independent approaches enhances the sensitivity of either approach alone. Our techniques were able to cultivate 43 of the 48 families detected by deep sequencing; the five families recovered solely by culture-independent approaches were all present at very low abundance (<0.002% total reads. 46% of the molecular signatures detected by culture from the six patients were only identified in an anaerobic environment, suggesting that a large proportion of the cultured airway community is composed of obligate anaerobes. Most significantly, using 20 growth conditions per specimen, half of which included anaerobic cultivation and extended incubation times we demonstrate that the majority of bacteria present can be cultured.

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

    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.

  12. Selective enrichment media bias the types of Salmonella enterica strains isolated from mixed strain cultures and complex enrichment broths.

    Gorski, Lisa

    2012-01-01

    For foodborne outbreak investigations it can be difficult to isolate the relevant strain from food and/or environmental sources. If the sample is contaminated by more than one strain of the pathogen the relevant strain might be missed. In this study mixed cultures of Salmonella enterica were grown in one set of standard enrichment media to see if culture bias patterns emerged. Nineteen strains representing four serogroups and ten serotypes were compared in four-strain mixtures in Salmonella-only and in cattle fecal culture enrichment backgrounds using Salmonella enrichment media. One or more strain(s) emerged as dominant in each mixture. No serotype was most fit, but strains of serogroups C2 and E were more likely to dominate enrichment culture mixtures than strains of serogroups B or C1. Different versions of Rappaport-Vassiliadis (RV) medium gave different patterns of strain dominance in both Salmonella-only and fecal enrichment culture backgrounds. The fittest strains belonged to serogroups C1, C2, and E, and included strains of S. Infantis, S. Thompson S. Newport, S. 6,8:d:-, and S. Give. Strains of serogroup B, which included serotypes often seen in outbreaks such as S. Typhimurium, S. Saintpaul, and S. Schwarzengrund were less likely to emerge as dominant strains in the mixtures when using standard RV as part of the enrichment. Using a more nutrient-rich version of RV as part of the protocol led to a different pattern of strains emerging, however some were still present in very low numbers in the resulting population. These results indicate that outbreak investigations of food and/or other environmental samples should include multiple enrichment protocols to ensure isolation of target strains of Salmonella.

  13. Composition of the bacterial community degrading Phaeocystis mucopolysaccharides in enrichment cultures

    Janse, Ingmar; Zwart, Gabriel; Maarel, Marc J.E.C. van der; Gottschal, Jan C.

    2000-01-01

    As described recently, mucopolysaccharides of the marine microalga Phaeocystis can be degraded in enrichment cultures. In this paper we report on the characterization of the microbial community in such enrichments. Denaturing gradient gel electrophoresis (DGGE) profiles that were obtained during muc

  14. Atrazine and its metabolites degradation in mineral salts medium and soil using an enrichment culture.

    Kumar, Anup; Singh, Neera

    2016-03-01

    An atrazine-degrading enrichment culture was used to study degradation of atrazine metabolites viz. hydroxyatrazine, deethylatrazine, and deisopropylatrazine in mineral salts medium. Results suggested that the enrichment culture was able to degrade only hydroxyatrazine, and it was used as the sole source of carbon and nitrogen. Hydroxyatrazine degradation slowed down when sucrose and/or ammonium hydrogen phosphate were supplemented as the additional sources of carbon and nitrogen, respectively. The enrichment culture could degrade high concentrations of atrazine (up to 110 μg/mL) in mineral salts medium, and neutral pH was optimum for atrazine degradation. Further, except in an acidic soil, enrichment culture was able to degrade atrazine in three soil types having different physico-chemical properties. Raising the pH of acidic soil to neutral or alkaline enabled the enrichment culture to degrade atrazine suggesting that acidic pH inhibited atrazine-degrading ability. The study suggested that the enrichment culture can be successfully utilized to achieve complete degradation of atrazine and its persistent metabolite hydroxyatrazine in the contaminated soil and water.

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

    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.

  16. Enrichment culture of marine anaerobic ammonium oxidation (anammox) bacteria

    GUAN Yong-jie

    2016-01-01

    The present study investigates the enrichment of anaerobic ammonium oxidation (anammox) bacteria in the marine environment using sediment samples obtained from the East China Sea and discusses the nitrogen removal efficiency of marine anammox bioreactor. Enrichment of anammox bacteria with simultaneous removal of nitrite and ammonium ions was observed in the Anaerobic Sequencing Batch Reactor under a total nitrogen loading rate of 0.37kg-N m-3day-1. In this study, The nitrogen removal efficiency was up to 80% and the molar-reaction ratio of ammonium, nitrite and nitrate was 1.0:1.22:0.22 which was a little different from a previously reported ratio of 1.0:1.32:0.26 in a freshwater system.

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

    Shiling eZheng

    2015-09-01

    Full Text Available 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.

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

    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

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

    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.

  20. Isolation, Characterization and Identification of Thiram-degrading Microorganisms from Soil Enrichment Cultures

    ŞAHİN, Nurettin

    2000-01-01

    Mixed microbial cultures were obtained by enrichment from soil samples collected from the Gediz basin. A number of species of bacteria and fungi were isolated and partially characterized from enrichment clutures containing the fungicide thiram. According to their responses in morphological and biochemical tests fungi were identified as Aspergillus niger, A. flavus and Penicilium steckii. Bacterial isolates were assigned to the genera: Bacillus, Arthrobacter, Moraxella-like Acinetobacter a...

  1. Differential gene expression profiling of enriched human spermatogonia after short- and long-term culture.

    Conrad, Sabine; Azizi, Hossein; Hatami, Maryam; Kubista, Mikael; Bonin, Michael; Hennenlotter, Jörg; Renninger, Markus; Skutella, Thomas

    2014-01-01

    This study aimed to provide a molecular signature for enriched adult human stem/progenitor spermatogonia during short-term (differentiation/spermatogenesis pathway were highly expressed in enriched short-term cultured spermatogonia. After long-term culture, a proportion of cells retained and aggravated the "spermatogonial" gene expression profile with the expression of germ and pluripotency-associated genes, while in the majority of long-term cultured cells this molecular profile, typical for the differentiation pathway, was reduced and more genes related to the extracellular matrix production and attachment were expressed. The approach we provide here to study the molecular status of in vitro cultured spermatogonia may be important to optimize the culture conditions and to evaluate the germ cell plasticity in the future.

  2. Detection of Salmonella invA gene in shrimp enrichment culture by polymerase chain reaction.

    Upadhyay, Bishnu Prasad; Utrarachkij, Fuangfa; Thongshoob, Jarinee; Mahakunkijcharoen, Yuvadee; Wongchinda, Niracha; Suthienkul, Orasa; Khusmith, Srisin

    2010-03-01

    Contamination of seafood with salmonellae is a major public health concern. Detection of Salmonella by standard culture methods is time consuming. In this study, an enrichment culture step prior to polymerase chain reaction (PCR) was applied to detect 284 bp fragment of Salmonella invA in comparison with the conventional culture method in 100 shrimp samples collected from four different shrimp farms and fresh food markets around Bangkok. Samples were pre-enriched in non-selective lactose broth (LB) and selective tetrathionate broth (TTB). PCR detection limit was 10 pg and 10(4) cfu/ml of viable salmonellae with 100% specificity. PCR assay detected 19 different Salmonella serovars belonging to 8 serogroups (B, C1, C2-C3, D1, E1, E4 and K) commonly found in clinical and environmental samples in Thailand. The detection rate of PCR following TTB enrichment (24%) was higher than conventional culture method (19%). PCR following TTB, but not in LB enrichment allowed salmonella detection with 84% sensitivity, 90% specificity and 89% accuracy. Shrimp samples collected from fresh food markets had higher levels of contaminated salmonellae than those from shrimp farms. The results indicated that incorporation of an enrichment step prior to PCR has the potential to be applied for detection of naturally contaminated salmonellae in food, environment and clinical samples.

  3. Differential Gene Expression Profiling of Enriched Human Spermatogonia after Short- and Long-Term Culture

    Sabine Conrad

    2014-01-01

    Full Text Available This study aimed to provide a molecular signature for enriched adult human stem/progenitor spermatogonia during short-term (<2 weeks and long-term culture (up to more than 14 months in comparison to human testicular fibroblasts and human embryonic stem cells. Human spermatogonia were isolated by CD49f magnetic activated cell sorting and collagen−/laminin+ matrix binding from primary testis cultures obtained from ten adult men. For transcriptomic analysis, single spermatogonia-like cells were collected based on their morphology and dimensions using a micromanipulation system from the enriched germ cell cultures. Immunocytochemical, RT-PCR and microarray analyses revealed that the analyzed populations of cells were distinct at the molecular level. The germ- and pluripotency-associated genes and genes of differentiation/spermatogenesis pathway were highly expressed in enriched short-term cultured spermatogonia. After long-term culture, a proportion of cells retained and aggravated the “spermatogonial” gene expression profile with the expression of germ and pluripotency-associated genes, while in the majority of long-term cultured cells this molecular profile, typical for the differentiation pathway, was reduced and more genes related to the extracellular matrix production and attachment were expressed. The approach we provide here to study the molecular status of in vitro cultured spermatogonia may be important to optimize the culture conditions and to evaluate the germ cell plasticity in the future.

  4. Breast Cancer Stem Cell Culture and Enrichment Using Poly(ε-Caprolactone Scaffolds

    Sònia Palomeras

    2016-04-01

    Full Text Available The cancer stem cell (CSC population displays self-renewal capabilities, resistance to conventional therapies, and a tendency to post-treatment recurrence. Increasing knowledge about CSCs’ phenotype and functions is needed to investigate new therapeutic strategies against the CSC population. Here, poly(ε-caprolactone (PCL, a biocompatible polymer free of toxic dye, has been used to fabricate scaffolds, solid structures suitable for 3D cancer cell culture. It has been reported that scaffold cell culture enhances the CSCs population. A RepRap BCN3D+ printer and 3 mm PCL wire were used to fabricate circular scaffolds. PCL design and fabrication parameters were first determined and then optimized considering several measurable variables of the resulting scaffolds. MCF7 breast carcinoma cell line was used to assess scaffolds adequacy for 3D cell culture. To evaluate CSC enrichment, the Mammosphere Forming Index (MFI was performed in 2D and 3D MCF7 cultures. Results showed that the 60° scaffolds were more suitable for 3D culture than the 45° and 90° ones. Moreover, 3D culture experiments, in adherent and non-adherent conditions, showed a significant increase in MFI compared to 2D cultures (control. Thus, 3D cell culture with PCL scaffolds could be useful to improve cancer cell culture and enrich the CSCs population.

  5. Microbial dynamics in anaerobic enrichment cultures degrading di-n-butyl phthalic acid ester

    Trably, Eric; Batstone, Damien J.; Christensen, Nina

    2008-01-01

    in enrichment cultures degrading phthalic acid esters under methanogenic conditions. A selection pressure was applied by adding DBP at 10 and 200 mg L(-1) in semi-continuous anaerobic reactors. The microbial dynamics were monitored using single strand conformation polymorphism (SSCP). While only limited abiotic...

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

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

  7. Using Enrichment Clusters to Address the Needs of Culturally and Linguistically Diverse Learners

    Allen, Jennifer K.; Robbins, Margaret A.; Payne, Yolanda Denise; Brown, Katherine Backes

    2016-01-01

    Using data from teacher interviews, classroom observations, and a professional development workshop, this article explains how one component of the schoolwide enrichment model (SEM) has been implemented at a culturally diverse elementary school serving primarily Latina/o and African American students. Based on a broadened conception of giftedness,…

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

    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…

  9. A strict anaerobic extreme thermophilic hydrogen-producing culture enriched from digested household waste

    Karakashev, Dimitar Borisov; Kotay, Shireen Meher; Trably, Eric;

    2009-01-01

    The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H-2) producers from digested household solid wastes. A strict anaerobic extreme thermophilic H-2 producing bacterial culture was enriched from a lab-scale digester treating household was...... from digested household wastes. This study provided a culture with a potential to be applied in reactor systems for extreme thermophilic H-2 production from complex organic wastes.......The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H-2) producers from digested household solid wastes. A strict anaerobic extreme thermophilic H-2 producing bacterial culture was enriched from a lab-scale digester treating household...... sources. Growth on glucose produced acetate, H-2 and carbon dioxide. Maximal H-2 production rate on glucose was 1.1 mmol l(-1) h(-1) with a maximum H-2 yield of 1.9 mole H-2 per mole glucose. 16S ribosomal DNA clone library analyses showed that the culture members were phylogenetically affiliated...

  10. Enrichment of cancer stem cell-like cells by culture in alginate gel beads.

    Xu, Xiao-xi; Liu, Chang; Liu, Yang; Yang, Li; Li, Nan; Guo, Xin; Sun, Guang-wei; Ma, Xiao-jun

    2014-05-10

    Cancer stem cells (CSCs) are most likely the reason of cancer reoccurrence and metastasis. For further elucidation of the mechanism underlying the characteristics of CSCs, it is necessary to develop efficient culture systems to culture and expand CSCs. In this study, a three-dimensional (3D) culture system based on alginate gel (ALG) beads was reported to enrich CSCs. Two cell lines derived from different histologic origins were encapsulated in ALG beads respectively and the expansion of CSCs was investigated. Compared with two-dimensional (2D) culture, the proportion of cells with CSC-like phenotypes was significantly increased in ALG beads. Expression levels of CSC-related genes were greater in ALG beads than in 2D culture. The increase of CSC proportion after being cultured within ALG beads was further confirmed by enhanced tumorigenicity in vivo. Moreover, increased metastasis ability and higher anti-cancer drug resistance were also observed in 3D-cultured cells. Furthermore, we found that it was hypoxia, through the upregulation of hypoxia-inducible factors (HIFs) that occurred in ALG beads to induce the increasing of CSC proportion. Therefore, ALG bead was an efficient culture system for CSC enrichment, which might provide a useful platform for CSC research and promote the development of new anti-cancer therapies targeting CSCs.

  11. Identification of triclosan-degrading bacteria in a triclosan enrichment culture using stable isotope probing.

    Lee, Do Gyun; Cho, Kun-Ching; Chu, Kung-Hui

    2014-02-01

    Triclosan, a widely used antimicrobial agent, is an emerging contaminant in the environment. Despite its antimicrobial character, biodegradation of triclosan has been observed in pure cultures, soils and activated sludge. However, little is known about the microorganisms responsible for the degradation in mixed cultures. In this study, active triclosan degraders in a triclosan-degrading enrichment culture were identified using stable isotope probing (SIP) with universally (13)C-labeled triclosan. Eleven clones contributed from active microorganisms capable of uptake the (13)C in triclosan were identified. None of these clones were similar to known triclosan-degraders/utilizers. These clones distributed among α-, β-, or γ-Proteobacteria: one belonging to Defluvibacter (α-Proteobacteria), seven belonging to Alicycliphilus (β-Proteobacteria), and three belonging to Stenotrophomonas (γ-Proteobacteria). Successive additions of triclosan caused a significant shift in the microbial community structure of the enrichment culture, with dominant ribotypes belonging to the genera Alicycliphilus and Defluvibacter. Application of SIP has successfully identified diverse uncultivable triclosan-degrading microorganisms in an activated sludge enrichment culture. The results of this study not only contributed to our understanding of the microbial ecology of triclosan biodegradation in wastewater, but also suggested that triclosan degraders are more phylogenetically diverse than previously reported.

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

    Fotidis, Ioannis; Wang, Han; Angelidaki, Irini

    tolerant methanogenic culture as potential bioaugmentation inoculum in a continuous stirred tank reactor (CSTR) operating under “inhibited steady-state”, triggered by high ammonia levels (5 g NH4+-N L-1). The results of the current study established for the first time that bioaugmentation of an enriched...... ammonia tolerant methanogen in a CSTR reactor could completely alleviate the ammonia inhibitory effect. Furthermore, it was found that bioaugmentation with the enriched culture resulted in 25% higher methane production compared to when the bioaugmentation was achieved with pure methanogenic strains....... The bioaugmentation was performed without pausing the continuous operation of the CSTR reactor and without excluding the ammonia-rich substrate from the feedstock. Thus, bioaugmentation with mixed methanogenic cultures could potentially support the development of an efficient and cost-effective biomethanation process...

  13. [Mass spectrometry assay for denitrifying enzyme activity measurement].

    Zhang, Li-li; Wu, Zhi-jie; Song, Yu-chao

    2010-07-01

    Nitrification inhibitors exert inhibition function in soil nitrification process (NH4(+)-N to NO3(-)-N) and are widely applied in order to improve N fertilizer use efficiency. Before the new nitrification inhibitor is used, its effects on denitrification process must be investigated and denitrifying enzyme activity (DEA) is an effective indicator to show this process. In the present paper, a mass spectrometery (MS) method was taken to measure the denitrifying enzyme activity in the new nitrification inhibitor 3, 4-dimethylpyrazole phosphate (DMPP) incubation system. The results showed that the method measured the concentration of N2O in the incubation system accurately and the concentration measured by MS had marked correlation with that measured by gas chromatogram (GC) (MS(N2O) = -0.45 + 1.03GC(N2O, R2 = 0.995). At the same time, enrichment of 15 N2O and 15 N2 was measured to discriminate the nitrate reductase and N2O reductase. Differed with traditional method, the enzymatic inhibitor-acetylene was not appended. The results showed that DMPP had no influence on the denitrifying enzyme activity and indicated that the denitrification process was not influenced by DMPP.

  14. Cholera Rapid Test with Enrichment Step Has Diagnostic Performance Equivalent to Culture

    Ontweka, Lameck N.; Deng, Lul O.; Rauzier, Jean; Debes, Amanda K.; Tadesse, Fisseha; Parker, Lucy A.; Wamala, Joseph F.; Bior, Bior K.; Lasuba, Michael; But, Abiem Bona; Grandesso, Francesco; Jamet, Christine; Cohuet, Sandra; Ciglenecki, Iza; Serafini, Micaela; Sack, David A.; Quilici, Marie-Laure; Azman, Andrew S.; Luquero, Francisco J.

    2016-01-01

    Cholera rapid diagnostic tests (RDT) could play a central role in outbreak detection and surveillance in low-resource settings, but their modest performance has hindered their broad adoption. The addition of an enrichment step may improve test specificity. We describe the results of a prospective diagnostic evaluation of the Crystal VC RDT (Span Diagnostics, India) with enrichment step and of culture, each compared to polymerase chain reaction (PCR), during a cholera outbreak in South Sudan. RDTs were performed on alkaline peptone water inoculated with stool and incubated for 4–6 hours at ambient temperature. Cholera culture was performed from wet filter paper inoculated with stool. Molecular detection of Vibrio cholerae O1 by PCR was done from dry Whatman 903 filter papers inoculated with stool, and from wet filter paper supernatant. In August and September 2015, 101 consecutive suspected cholera cases were enrolled, of which 36 were confirmed by PCR. The enriched RDT had 86.1% (95% CI: 70.5–95.3) sensitivity and 100% (95% CI: 94.4–100) specificity compared to PCR as the reference standard. The sensitivity of culture versus PCR was 83.3% (95% CI: 67.2–93.6) for culture performed on site and 72.2% (95% CI: 54.8–85.8) at the international reference laboratory, where samples were tested after an average delay of two months after sample collection, and specificity was 98.5% (95% CI: 91.7–100) and 100% (95% CI: 94.5–100), respectively. The RDT with enrichment showed performance comparable to that of culture and could be a sustainable alternative to culture confirmation where laboratory capacity is limited. PMID:27992488

  15. Cholera Rapid Test with Enrichment Step Has Diagnostic Performance Equivalent to Culture.

    Ontweka, Lameck N; Deng, Lul O; Rauzier, Jean; Debes, Amanda K; Tadesse, Fisseha; Parker, Lucy A; Wamala, Joseph F; Bior, Bior K; Lasuba, Michael; But, Abiem Bona; Grandesso, Francesco; Jamet, Christine; Cohuet, Sandra; Ciglenecki, Iza; Serafini, Micaela; Sack, David A; Quilici, Marie-Laure; Azman, Andrew S; Luquero, Francisco J; Page, Anne-Laure

    2016-01-01

    Cholera rapid diagnostic tests (RDT) could play a central role in outbreak detection and surveillance in low-resource settings, but their modest performance has hindered their broad adoption. The addition of an enrichment step may improve test specificity. We describe the results of a prospective diagnostic evaluation of the Crystal VC RDT (Span Diagnostics, India) with enrichment step and of culture, each compared to polymerase chain reaction (PCR), during a cholera outbreak in South Sudan. RDTs were performed on alkaline peptone water inoculated with stool and incubated for 4-6 hours at ambient temperature. Cholera culture was performed from wet filter paper inoculated with stool. Molecular detection of Vibrio cholerae O1 by PCR was done from dry Whatman 903 filter papers inoculated with stool, and from wet filter paper supernatant. In August and September 2015, 101 consecutive suspected cholera cases were enrolled, of which 36 were confirmed by PCR. The enriched RDT had 86.1% (95% CI: 70.5-95.3) sensitivity and 100% (95% CI: 94.4-100) specificity compared to PCR as the reference standard. The sensitivity of culture versus PCR was 83.3% (95% CI: 67.2-93.6) for culture performed on site and 72.2% (95% CI: 54.8-85.8) at the international reference laboratory, where samples were tested after an average delay of two months after sample collection, and specificity was 98.5% (95% CI: 91.7-100) and 100% (95% CI: 94.5-100), respectively. The RDT with enrichment showed performance comparable to that of culture and could be a sustainable alternative to culture confirmation where laboratory capacity is limited.

  16. Phylogenetic and functional diversity of denitrifying bacteria isolated from various rice paddy and rice-soybean rotation fields.

    Tago, Kanako; Ishii, Satoshi; Nishizawa, Tomoyasu; Otsuka, Shigeto; Senoo, Keishi

    2011-01-01

    Denitrifiers can produce and consume nitrous oxide (N(2)O). While little N(2)O is emitted from rice paddy soil, the same soil produces N(2)O when the land is drained and used for upland crop cultivation. In this study, we collected soils from two types of fields each at three locations in Japan; one type of field had been used for continuous cultivation of rice and the other for rotational cultivation of rice and soybean. Active denitrifiers were isolated from these soils using a functional single-cell isolation method, and their taxonomy and denitrifying properties were examined. A total of 110 denitrifiers were obtained, including those previously detected by a culture-independent analysis. Strains belonging to the genus Pseudogulbenkiania were dominant at all locations, suggesting that Pseudogulbenkiania denitrifiers are ubiquitous in various rice paddy soils. Potential denitrifying activity was similar among the strains, regardless of the differences in taxonomic position and soil of origin. However, relative amounts of N(2) in denitrification end products varied among strains isolated from different locations. Our results also showed that crop rotation had minimal impact on the functional diversity of the denitrifying strains. These results indicate that soil and other environmental factors, excluding cropping systems, could select for N(2)-producing denitrifiers.

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

    McIlroy, Simon Jon; Szyszka, Anna; Starnawski, Piotr Marian;

    2016-01-01

    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...

  18. Halobacterium denitrificans sp. nov., an extremely halophilic denitrifying bacterium

    Tomlinson, G. A.; Jahnke, L. L.; Hochstein, L. I.

    1986-01-01

    Halobacterium denitrificans was one of several carbohydrate-utilizing, denitrifying, extremely halophilic bacteria isolated by anaerobic enrichment in the presence of nitrate. Anaerobic growth took place only when nitrate (or nitrite) was present and was accompanied by the production of dinitrogen. In the presence of high concentrations of nitrate (i.e., 0.5 percent), nitrous oxide and nitrite were also detected. When grown aerobically in a mineral-salts medium containing 0.005 percent yeast extract, H. denitrificans utilized a variety of carbohydrates as sources of carbon and energy. In every case, carbohydrate utilization was accompanied by acid production.

  19. Halobacterium denitrificans sp. nov. - An extremely halophilic denitrifying bacterium

    Tomlinson, G. A.; Jahnke, L. L.; Hochstein, L. I.

    1986-01-01

    Halobacterium denitrificans was one of several carbohydrate-utilizing, denitrifying, extremely halophilic bacteria isolated by anaerobic enrichment in the presence of nitrate. Anaerobic growth took place only when nitrate (or nitrite) was present and was accompanied by the production of dinitrogen. In the presence of high concentrations of nitrate (i.e., 0.5 percent), nitrous oxide and nitrite were also detected. When grown aerobically in a mineral-salts medium containing 0.005 percent yeast extract, H. denitrificans utilized a variety of carbohydrates as sources of carbon and energy. In every case, carbohydrate utilization was accompanied by acid production.

  20. Microbial degradation of chloro- and methylphenol mixtures under aerobic and denitrifying conditions. Regulation and interaction in a mixed culture; Mikrobieller Abbau von Chlor- und Methylphenolen im Gemisch unter aeroben und denitrifizierenden Bedingungen. Regulation und Interaktion in einer Mischkultur

    Hollender, J.

    1994-12-31

    The mechanism and the regulation of the microbial aerobic degradation of chloro- and methylphenol mixtures were investigated by comparing the mixed culture enriched of these phenolic compounds with the isolated pure cultures. The degradation assays and the characterization of the central degrading enzymes involved show that the degradation potential of the mixed culture was essentially determined by the additive abilities of the three pure cultures Alcaligenes xylosoxidans subspecies denitrificans JH1, Pseudomonas stutzeri JH3 and Comamonas testosteroni JH5. Degradation of some substrate mixtures and avoidance of enrichment of metabolites can only be explained by the interaction of the pure cultures or the participation of other organisms in the mixed culture which were not further investigated. (orig.) [Deutsch] Bei den Untersuchungen zum Mechanismus und der Regulation des aeroben Abbaus von Chlor- und Methylphenolen im Gemisch stand der Vergleich zwischen der auf diesen Phenolen angereicherten Mischkultur und den daraus isolierten Reinkulturen im Vordergrund. Die Abbauversuche und die Charakterisierung der am Metabolismus beteiligten zentralen Enzyme zeigen, dass fuer das Abbaupotential der Mischkultur im wesentlichen die additiven Abbauleistungen der drei Reinkulturen Alcaligenes xylosoxidans subspecies dentrificans JH1, Pseudomonas stutzeri JH3 und Comamonas testosteroni JH5 verantwortlich sind. Der Abbau einiger Substratmischungen und die Vermeidung einer Anreicherung von Metaboliten in der Mischkultur sind jedoch nur durch eine Interaktion der Reinkulturen oder durch eine Beteiligung anderer nicht naeher untersuchter Organismen in der Mischkultur zu erklaeren. (orig.)

  1. Identification of the autotrophic denitrifying community in nitrate removal reactors by DNA-stable isotope probing.

    Xing, Wei; Li, Jinlong; Cong, Yuan; Gao, Wei; Jia, Zhongjun; Li, Desheng

    2017-04-01

    Autotrophic denitrification has attracted increasing attention for wastewater with insufficient organic carbon sources. Nevertheless, in situ identification of autotrophic denitrifying communities in reactors remains challenging. Here, a process combining micro-electrolysis and autotrophic denitrification with high nitrate removal efficiency was presented. Two batch reactors were fed organic-free nitrate influent, with H(13)CO3(-) and H(12)CO3(-) as inorganic carbon sources. DNA-based stable-isotope probing (DNA-SIP) was used to obtain molecular evidence for autotrophic denitrifying communities. The results showed that the nirS gene was strongly labeled by H(13)CO3(-), demonstrating that the inorganic carbon source was assimilated by autotrophic denitrifiers. High-throughput sequencing and clone library analysis identified Thiobacillus-like bacteria as the most dominant autotrophic denitrifiers. However, 88% of nirS genes cloned from the (13)C-labeled "heavy" DNA fraction showed low similarity with all culturable denitrifiers. These findings provided functional and taxonomical identification of autotrophic denitrifying communities, facilitating application of autotrophic denitrification process for wastewater treatment.

  2. Developments in techniques for the isolation, enrichment, main culture conditions and identification of spermatogonial stem cells.

    He, Yanan; Chen, Xiaoli; Zhu, Huabin; Wang, Dong

    2015-12-01

    The in vitro culture system of spermatogonial stem cells (SSCs) provides a basis for studies on spermatogenesis, and also contributes to the development of new methods for the preservation of livestock and animal genetic modification. In vitro culture systems have mainly been established for mouse SSCs, but are lacking for farm animals. We reviewed and analyzed the current progress in SSC techniques such as isolation, purification, cultivation and identification. Based on the published studies, we concluded that two-step enzyme digestion and magnetic-activated cell sorting are fast becoming the main methods for isolation and enrichment of SSCs. With regard to the culture systems, serum and feeders were earlier thought to play an important role in the self-renewal and proliferation of SSCs, but serum- and feeder-free culture systems as a means of overcoming the limitations of SSC differentiation in long-term SSC culture are being explored. However, there is still a need to establish more efficient and ideal culture systems that can also be used for SSC culture in larger mammals. Although the lack of SSC-specific surface markers has seriously affected the efficiency of purification and identification, the transgenic study is helpful for our identification of SSCs. Therefore, future studies on SSC techniques should focus on improving serum- and feeder-free culture techniques, and discovering and identifying specific surface markers of SSCs, which will provide new ideas for the optimization of SSC culture systems for mice and promote related studies in farm animals.

  3. Innovative Approaches Using Lichen Enriched Media to Improve Isolation and Culturability of Lichen Associated Bacteria

    Biosca, Elena G.; Flores, Raquel; Santander, Ricardo D.; Díez-Gil, José Luis; Barreno, Eva

    2016-01-01

    Lichens, self-supporting mutualistic associations between a fungal partner and one or more photosynthetic partners, also harbor non-photosynthetic bacteria. The diversity and contribution of these bacteria to the functioning of lichen symbiosis have recently begun to be studied, often by culture-independent techniques due to difficulties in their isolation and culture. However, culturing as yet unculturable lichenic bacteria is critical to unravel their potential functional roles in lichen symbiogenesis, to explore and exploit their biotechnological potential and for the description of new taxa. Our objective was to improve the recovery of lichen associated bacteria by developing novel isolation and culture approaches, initially using the lichen Pseudevernia furfuracea. We evaluated the effect of newly developed media enriched with novel lichen extracts, as well as the influence of thalli washing time and different disinfection and processing protocols of thalli. The developed methodology included: i) the use of lichen enriched media to mimic lichen nutrients, supplemented with the fungicide natamycin; ii) an extended washing of thalli to increase the recovery of ectolichenic bacteria, thus allowing the disinfection of thalli to be discarded, hence enhancing endolichenic bacteria recovery; and iii) the use of an antioxidant buffer to prevent or reduce oxidative stress during thalli disruption. The optimized methodology allowed significant increases in the number and diversity of culturable bacteria associated with P. furfuracea, and it was also successfully applied to the lichens Ramalina farinacea and Parmotrema pseudotinctorum. Furthermore, we provide, for the first time, data on the abundance of culturable ecto- and endolichenic bacteria that naturally colonize P. furfuracea, R. farinacea and P. pseudotinctorum, some of which were only able to grow on lichen enriched media. This innovative methodology is also applicable to other microorganisms inhabiting these

  4. Isolation of Cultured Endothelial Progenitor Cells in vitro from PBMCs and CD133~+ Enriched Cells

    郑伟红; 万亚峰; 马小鹏; 李兴睿; 杨志芳; 殷茜; 易继林

    2010-01-01

    Two isolation methods for sorting of endothelial progenitor cells(EPCs):from peripheral blood mononuclear cells(PBMCs)and CD133+ enriched cells were compared,by defining the cell morphology,phenotype,reproductive activities and function in vitro,to provide a reference for clinical application of EPCs.PBMCs from healthy subjects were used either directly for cell culture or for CD133+ sorting.The two groups of cells were cultured in complete medium 199(M199)for 7 to 14 days and the phenotypes of EPCs were an...

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

    Tan, Boonfei; Fowler, S Jane; Abu Laban, Nidal; 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.

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

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

    2015-01-01

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

    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.

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

    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 α-proteobacteria followed by γ-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.

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

    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...

  10. High-efficiency hydrogen production by an anaerobic, thermophilic enrichment culture from an Icelandic hot spring.

    Koskinen, Perttu E P; Lay, Chyi-How; Puhakka, Jaakko A; Lin, Ping-Jei; Wu, Shu-Yii; Orlygsson, Jóhann; Lin, Chiu-Yue

    2008-11-01

    Dark fermentative hydrogen production from glucose by a thermophilic culture (33HL), enriched from an Icelandic hot spring sediment sample, was studied in two continuous-flow, completely stirred tank reactors (CSTR1, CSTR2) and in one semi-continuous, anaerobic sequencing batch reactor (ASBR) at 58 degrees C. The 33HL produced H2 yield (HY) of up to 3.2 mol-H2/mol-glucose along with acetate in batch assay. In the CSTR1 with 33HL inoculum, H2 production was unstable. In the ASBR, maintained with 33HL, the H2 production enhanced after the addition of 6 mg/L of FeSO4 x H2O resulting in HY up to 2.51 mol-H2/mol-glucose (H2 production rate (HPR) of 7.85 mmol/h/L). The H2 production increase was associated with an increase in butyrate production. In the CSTR2, with ASBR inoculum and FeSO4 supplementation, stable, high-rate H2 production was obtained with HPR up to 45.8 mmol/h/L (1.1 L/h/L) and HY of 1.54 mol-H2/mol-glucose. The 33HL batch enrichment was dominated by bacterial strains closely affiliated with Thermobrachium celere (99.8-100%). T. celere affiliated strains, however, did not thrive in the three open system bioreactors. Instead, Thermoanaerobacterium aotearoense (98.5-99.6%) affiliated strains, producing H2 along with butyrate and acetate, dominated the reactor cultures. This culture had higher H2 production efficiency (HY and specific HPR) than reported for mesophilic mixed cultures. Further, the thermophilic culture readily formed granules in CSTR and ASBR systems. In summary, the thermophilic culture as characterized by high H2 production efficiency and ready granulation is considered very promising for H2 fermentation from carbohydrates.

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

    Luo, Gang; Angelidaki, Irini

    2012-01-01

    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 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......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...

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

    Luo, Gang; Angelidaki, Irini

    2012-11-01

    Biogas produced by anaerobic digestion, is mainly used in a gas motor for heat and electricity production. However, after removal of CO(2) , 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 CO(2) to CH(4) by addition of H(2) . Enrichment at thermophilic temperature (55°C) resulted in CO(2) and H(2) bioconversion rate of 320 mL CH(4) /(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 CH(4) 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 CH(4) content to around 90%. Further study showed that by decreasing the gas-liquid mass transfer by increasing the stirring speed of the mixture the CH(4) content was increased to around 95%. Finally, the CH(4) content around 90% was achieved in this study with the gas injection rate as high as 24 L/(L day).

  13. Identification of novel glycosyl hydrolases with cellulolytic activity against crystalline cellulose from metagenomic libraries constructed from bacterial enrichment cultures.

    Mori, Toshio; Kamei, Ichiro; Hirai, Hirofumi; Kondo, Ryuichiro

    2014-01-01

    To obtain cellulases that are capable of degrading crystalline cellulose and cedar wood, metagenomic libraries were constructed from raw soil sample which was covered to pile of cedar wood sawdust or from its enrichment cultures. The efficiency of screening of metagenomic library was improved more than 3 times by repeating enrichment cultivation using crystalline cellulose as a carbon source, compared with the library constructed from raw soil. Four cellulase genes were obtained from the metagenomic libraries that were constructed from the total genome extracted from an enrichment culture that used crystalline cellulose as a carbon source. A cellulase gene and a xylanase gene were obtained from the enrichment culture that used unbleached kraft pulp as a carbon source. The culture supernatants of Escherichia coli expressing three clones that were derived from the enrichment culture that used crystalline cellulose showed activity against crystalline cellulose. In addition, these three enzyme solutions generated a reducing sugar from cedar wood powder. From these results, the construction of a metagenomic library from cultures that were repetition enriched using crystalline cellulose demonstrated that this technique is a powerful tool for obtaining cellulases that have activity toward crystalline cellulose.

  14. Inhibition of anaerobic ammonium oxidizing (anammox) enrichment cultures by substrates, metabolites and common wastewater constituents.

    Carvajal-Arroyo, José M; Sun, Wenjie; Sierra-Alvarez, Reyes; Field, Jim A

    2013-03-01

    Anaerobic ammonium oxidation (anammox) is an emerging technology for nitrogen removal that provides a more environmentally sustainable and cost effective alternative compared to conventional biological treatment methods. The objective of this study was to investigate the inhibitory impact of anammox substrates, metabolites and common wastewater constituents on the microbial activity of two different anammox enrichment cultures (suspended and granular), both dominated by bacteria from the genus Brocadia. Inhibition was evaluated in batch assays by comparing the N(2) production rates in the absence or presence of each compound supplied in a range of concentrations. The optimal pH was 7.5 and 7.3 for the suspended and granular enrichment cultures, respectively. Among the substrates or products, ammonium and nitrate caused low to moderate inhibition, whereas nitrite caused almost complete inhibition at concentrations higher than 15 mM. The intermediate, hydrazine, either stimulated or caused low inhibition of anammox activity up to 3mM. Of the common constituents in wastewater, hydrogen sulfide was the most severe inhibitor, with 50% inhibitory concentrations (IC(50)) as low as 0.03 mM undissociated H(2)S. Dissolved O(2) showed moderate inhibition (IC(50)=2.3-3.8 mg L(-1)). In contrast, phosphate and salinity (NaCl) posed very low inhibition. The suspended- and granular anammox enrichment cultures had similar patterns of response to the various inhibitory stresses with the exception of phosphate. The findings of this study provide comprehensive insights on the tolerance of the anammox process to a wide variety of potential inhibiting compounds.

  15. Neonicotinoid Insecticides Alter the Gene Expression Profile of Neuron-Enriched Cultures from Neonatal Rat Cerebellum

    Junko Kimura-Kuroda

    2016-10-01

    Full Text Available Neonicotinoids are considered safe because of their low affinities to mammalian nicotinic acetylcholine receptors (nAChRs relative to insect nAChRs. However, because of importance of nAChRs in mammalian brain development, there remains a need to establish the safety of chronic neonicotinoid exposures with regards to children’s health. Here we examined the effects of longterm (14 days and low dose (1 μM exposure of neuron-enriched cultures from neonatal rat cerebellum to nicotine and two neonicotinoids: acetamiprid and imidacloprid. Immunocytochemistry revealed no differences in the number or morphology of immature neurons or glial cells in any group versus untreated control cultures. However, a slight disturbance in Purkinje cell dendritic arborization was observed in the exposed cultures. Next we performed transcriptome analysis on total RNAs using microarrays, and identified significant differential expression (p < 0.05, q < 0.05, ≥1.5 fold between control cultures versus nicotine-, acetamiprid-, or imidacloprid-exposed cultures in 34, 48, and 67 genes, respectively. Common to all exposed groups were nine genes essential for neurodevelopment, suggesting that chronic neonicotinoid exposure alters the transcriptome of the developing mammalian brain in a similar way to nicotine exposure. Our results highlight the need for further careful investigations into the effects of neonicotinoids in the developing mammalian brain.

  16. Batch fermentative hydrogen production by enriched mixed culture: Combination strategy and their microbial composition.

    Sivagurunathan, Periyasamy; Sen, Biswarup; Lin, Chiu-Yue

    2014-02-01

    The effect of individual and combined mixed culture on dark fermentative hydrogen production performance was investigated. Mixed cultures from cow dung (C1), sewage sludge (C2), and pig slurry (C3) were enriched under strict anaerobic conditions at 37°C with glucose as the sole carbon source. Biochemical hydrogen production test in peptone-yeast-glucose (PYG) and basal medium was performed for individual mixed cultures (C1, C2 and C3) and their combinations (C1-C2, C2-C3, C1-C3 and C1-C2-C3) at a glucose concentration of 10 g/L, 37°C and initial pH 7. Maximum hydrogen yields (HY) of 2.0 and 1.86 [Formula: see text] by C2, and 1.98 and 1.95 mol(H2)/mol(glucose) by C2-C3 were obtained in PYG and basal medium, respectively. Butyrate and acetate were the major soluble metabolites produced by all the cultures, and the ratio of butyrate to acetate was ∼2 fold higher in basal medium than PYG medium, indicating strong influence of media formulation on glucose catabolism. The major hydrogen-producing bacterial strains, observed in all mixed cultures, belonged to Clostridium butyricum, C. saccharobutylicum, C. tertium and C. perfringens. The hydrogen production performance of the combined mixed culture (C2-C3) was further evaluated on beverage wastewater (10 g/L) at pH 7 and 37°C. The results showed an HY of 1.92 mol(H2)/mol(glucose-equivalent). Experimental evidence suggests that hydrogen fermentation by mixed culture combination could be a novel strategy to improve the HY from industrial wastewater.

  17. Regulation of Liver Enriched Transcription Factors in Rat Hepatocytes Cultures on Collagen and EHS Sarcoma Matrices.

    Jürgen Borlak

    Full Text Available Liver-enriched transcription factors (LETF play a crucial role in the control of liver-specific gene expression and for hepatocytes to retain their molecular and cellular functions complex interactions with extra cellular matrix (ECM are required However, during cell isolation ECM interactions are disrupted and for hepatocytes to regain metabolic competency cells are cultured on ECM substrata. The regulation of LETFs in hepatocytes cultured on different ECM has not been studied in detail. We therefore compared two common sources of ECM and evaluated cellular morphology and hepatocyte differentiation by investigating DNA binding activity of LETFs at gene specific promoters and marker genes of hepatic metabolism. Furthermore, we studied testosterone metabolism and albumin synthesis to assess the metabolic competence of cell cultures. Despite significant difference in morphological appearance and except for HNF1β (p<0.001 most LETFs and several of their target genes did not differ in transcript expression after Bonferroni adjustment when cultured on collagen or Matrigel. Nonetheless, Western blotting revealed HNF1β, HNF3α, HNF3γ, HNF4α, HNF6 and the smaller subunits of C/EBPα and C/EBPβ to be more abundant on Matrigel cultured cells. Likewise, DNA binding activity of HNF3α, HNF3β, HNF4α, HNF6 and gene expression of hepatic lineage markers were increased on Matrigel cultured hepatocytes. To further investigate hepatic gene regulation, the effects of Aroclor 1254 treatment, e.g. a potent inducer of xenobiotic defense were studied in vivo and in vitro. The gene expression of C/EBP-α increased in rat liver and hepatocytes cultured on collagen and this treatment induced DNA binding activity of HNF4α, C/EBPα and C/EBPβ and gene expression of CYP1A1 and CYP1A2 in vivo and in vitro. Taken collectively, two sources of ECM greatly affected hepatocyte morphology, activity of liver enriched transcription factors, hepatic gene expression and

  18. Denitrifying Bacteria in Paddy Soils of Taihu Lake Basin,China

    ZHANG Hua-Yong; LI Zhen-Gao; PAN Ying-Hua; LI Liang-Mo

    2004-01-01

    This study attempted to determine the characteristics of the communities, the ecological factors, and the denitrifying enzyme activity for denitrifying bacteria found in the paddy soils of the Taihu Lake Basin, China. Samples of the six main soil types of the basin were taken from paddy fields with different fertilities. The total numbers of bacteria and denitrifying bacteria in the high fertility soils were much more than those in low fertility soils, and the number of denitrifying bacteria accounted for 49% to 80% of the total number of bacteria. The O2 content was an important ecological factor that affected denitrification. Of test the strains isolated from the paddy soils in the Taihu Lake Basin, some (e.g., Pseudomonas spp.)grew well under low oxygen partial pressure, while others (e.g., Bacillus spp.) had no strict predilection with O2 content.Another critical ecological factor was the nitrogen concentration. Three selected denitrifying bacteria grew better in a culture medium with 135 instead of 276 mg L-1 nitrogen. At the same time 67% of the test strains were able to reduce NO-3 to NO-2 and 56% had N2O reductase.

  19. Phylogenetic analysis of aerobic freshwater and marine enrichment cultures efficient in hydrocarbon degradation: effect of profiling method

    Chang, Y.J.; Stephen, J.R.; Richter, A.P.; Venosa, A.D.; Bruggemann, J.; MacNaughton, S.J.; Kowalchuk, G.A.; Haines, J.R.; Kline, E.; White, D.C.

    2000-01-01

    Aerobically grown enrichment cultures derived from hydrocarbon- contaminated seawater and freshwater sediments were generated by growth on crude oil as sole carbon source. Both cultures displayed a high rate of degradation for a wide range of hydrocarbon compounds. The bacterial species composition

  20. Impact of arachidonic acid enrichment of live rotifer prey on bacterial communities in rotifer and larval fish cultures.

    Seychelles, Laurent H; Doiron, Kim; Audet, Céline; Tremblay, Réjean; Pernet, Fabrice; Lemarchand, Karine

    2013-03-01

    Rotifers (Brachionus plicatilis), commonly used at first feeding in commercial fish hatcheries, carry a large bacteria load. Because they are relatively poor in essential fatty acids, it is common practice to enrich them with fatty acids, including arachidonic acid (AA). This study aims to determine whether prey enrichment with AA may act as a prebiotic and modify the microbial community composition either in AA-enriched rotifer cultures or in larval-rearing water using winter flounder (Pseudopleuronectes americanus) as a larval fish model. AA enrichment modified the bacterial community composition in both the rotifer culture tanks and the larval-rearing tanks. We observed an increase in the number of cultivable bacteria on TCBS (thiosulfate-citrate-bile salts-sucrose) agar, used as a proxy for the abundance of Vibrio sp. The results suggest that AA may also play an indirect role in larval health.

  1. Denitrifying kinetics and nitrous oxide emission under different copper concentrations.

    Wu, Guangxue; Zhai, Xiaofeng; Jiang, Chengai; Guan, Yuntao

    2014-01-01

    Denitrifying activities and nitrous oxide (N2O) emission during denitrification can be affected by copper concentrations. Different denitrifiers were acclimated in sequencing batch reactors with acetate or methanol as the electron donor and nitrate as the electron acceptor. The effect of copper concentrations on the denitrifying activity and N2O emission for the acclimated denitrifiers was examined in batch experiments. Denitrifying activities of the acclimated denitrifiers declined with increasing copper concentrations, and the copper concentration exhibited a higher effect on denitrifiers acclimated with acetate than those acclimated with methanol. Compared with the control without the addition of copper, at the copper concentration of 1 mg/L, the acetate utilization rate reduced by 89% for acetate-acclimated denitrifiers, while the methanol utilization rate only reduced by 15% for methanol-acclimated denitrifiers. Copper also had different effects on N2O emission during denitrification carried out by various types of denitrifiers. For the acetate-acclimated denitrifiers, N2O emission initially increased and then decreased with increasing copper concentrations, while for the methanol-acclimated denitrifiers, N2O emission decreased with increasing copper concentrations.

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

    Jennifer L. 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.

  3. Persistence of pentolite (PETN and TNT) in soil microcosms and microbial enrichment cultures.

    Arbeli, Ziv; Garcia-Bonilla, Erika; Pardo, Cindy; Hidalgo, Kelly; Velásquez, Trigal; Peña, Luis; C, Eliana Ramos; Avila-Arias, Helena; Molano-Gonzalez, Nicolás; Brandão, Pedro F B; Roldan, Fabio

    2016-05-01

    Pentolite is a mixture (1:1) of 2,4,6-trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN), and little is known about its fate in the environment. This study was aimed to determine the dissipation of pentolite in soils under laboratory conditions. Microcosm experiments conducted with two soils demonstrated that dissipation rate of PETN was significantly slower than that of TNT. Interestingly, the dissipation of PETN was enhanced by the presence of TNT, while PETN did not enhanced the dissipation of TNT. Pentolite dissipation rate was significantly faster under biostimulation treatment (addition of carbon source) in soil from the artificial wetland, while no such stimulation was observed in soil from detonation field. In addition, the dissipation rate of TNT and PETN in soil from artificial wetland under biostimulation was significantly faster than the equivalent abiotic control, although it seems that non-biological processes might also be important for the dissipation of TNT and PETN. Transformation of PETN was also slower during establishment of enrichment culture using pentolite as the sole nitrogen source. In addition, transformation of these explosives was gradually reduced and practically stopped after the forth cultures transfer (80 days). DGGE analysis of bacterial communities from these cultures indicates that all consortia were dominated by bacteria from the order Burkholderiales and Rhodanobacter. In conclusion, our results suggest that PETN might be more persistent than TNT.

  4. Phylogenetic analysis of anaerobic psychrophilic enrichment cultures obtained from a greenland glacier ice core

    Sheridan, Peter P.; Miteva, Vanya I.; Brenchley, Jean E.

    2003-01-01

    The examination of microorganisms in glacial ice cores allows the phylogenetic relationships of organisms frozen for thousands of years to be compared with those of current isolates. We developed a method for aseptically sampling a sediment-containing portion of a Greenland ice core that had remained at -9 degrees C for over 100,000 years. Epifluorescence microscopy and flow cytometry results showed that the ice sample contained over 6 x 10(7) cells/ml. Anaerobic enrichment cultures inoculated with melted ice were grown and maintained at -2 degrees C. Genomic DNA extracted from these enrichments was used for the PCR amplification of 16S rRNA genes with bacterial and archaeal primers and the preparation of clone libraries. Approximately 60 bacterial inserts were screened by restriction endonuclease analysis and grouped into 27 unique restriction fragment length polymorphism types, and 24 representative sequences were compared phylogenetically. Diverse sequences representing major phylogenetic groups including alpha, beta, and gamma Proteobacteria as well as relatives of the Thermus, Bacteroides, Eubacterium, and Clostridium groups were found. Sixteen clone sequences were closely related to those from known organisms, with four possibly representing new species. Seven sequences may reflect new genera and were most closely related to sequences obtained only by PCR amplification. One sequence was over 12% distant from its closest relative and may represent a novel order or family. These results show that phylogenetically diverse microorganisms have remained viable within the Greenland ice core for at least 100,000 years.

  5. Selective enrichment and production of highly urease active bacteria by non-sterile (open) chemostat culture.

    Cheng, Liang; Cord-Ruwisch, Ralf

    2013-10-01

    In general, bioprocesses can be subdivided into naturally occurring processes, not requiring sterility (e.g., beer brewing, wine making, lactic acid fermentation, or biogas digestion) and other processes (e.g., the production of enzymes and antibiotics) that typically require a high level of sterility to avoid contaminant microbes overgrowing the production strain. The current paper describes the sustainable, non-sterile production of an industrial enzyme using activated sludge as inoculum. By using selective conditions (high pH, high ammonia concentration, and presence of urea) for the target bacterium, highly active ureolytic bacteria, physiologically resembling Sporosarcina pasteurii were reproducibly enriched and then continuously produced via chemostat operation of the bioreactor. When using a pH of 10 and about 0.2 M urea in a yeast extract-based medium, ureolytic bacteria developed under aerobic chemostat operation at hydraulic retention times of about 10 h with urease levels of about 60 μmol min⁻¹ ml⁻¹ culture. For cost minimization at an industrial scale the costly protein-rich yeast extract medium could be replaced by commercial milk powder or by lysed activated sludge. Glutamate, molasses, or glucose-based media did not result in the enrichment of ureolytic bacteria by the chemostat. The concentration of intracellular urease was sufficiently high such that the produced raw effluent from the reactor could be used directly for biocementation in the field.

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

    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)

  7. Detection of Yersinia spp. in meat products by enrichment culture, immunomagnetic separation and nested PCR.

    Estrada, Cecilia S M Lucero; Velázquez, Lidia Del Carmen; Favier, Gabriela Isabel; Genaro, María Silvia Di; Escudero, María Esther

    2012-05-01

    The prevalence of Yersinia enterocolitica in meat products was assessed by four methods: cold enrichment in trypticase soy broth (A), enrichment in modified Rappaport broth at 25 °C (B), concentration by immunomagnetic separation (C) and yadA nested PCR (D). Furthermore, the pathogenic potentials of the isolates were established by phenotypic and genotypic tests, and their genomic relationships were determined by pulsed-field gel electrophoresis (PFGE). A total of 238 samples were collected at retail level in the city of San Luis, Argentina, during the period 2007-2008. The highest Yersinia prevalence in meat products was observed by method D (92 positive samples), followed by methods A (13 positive samples) and C (5 positive samples); however, no isolation was obtained by method B. Fourteen Y. enterocolitica and 4 Yersinia intermedia strains were recovered by culture. All Y. enterocolitica 2/O:9 strains gave results related to virulence by phenotypic tests and exhibited the genotype virF(+)myfA(+)ail(+)ystA(+). Two biotype 1A strains showed a genotype virF(-)myfA(-)ail(+)ystA(+)ystB(+). The 14 Y. enterocolitica strains isolated during this work plus one reference strain were separated into 11 genomic types by PFGE. This genomic heterogeneity of the isolates shows the diversity of Y. enterocolitica strains in our region. It is the first time that IMS was used to search Y. enterocolitica strains from naturally contaminated meat products.

  8. Hydrogenotrophic culture enrichment reveals rumen Lachnospiraceae and Ruminococcaceae acetogens and hydrogen-responsive Bacteroidetes from pasture-fed cattle.

    Gagen, Emma J; Padmanabha, Jagadish; Denman, Stuart E; McSweeney, Christopher S

    2015-07-01

    Molecular information suggests that there is a broad diversity of acetogens in the rumen, distinct from any currently isolated acetogens. We combined molecular analysis with enrichment culture techniques to investigate this diversity further. Methane-inhibited, hydrogenotrophic enrichment cultures produced acetate as the dominant end product. Acetyl-CoA synthase gene analysis revealed putative acetogens in the cultures affiliated with the Lachnospiraceae and Ruminococcaceae as has been found in other rumen studies. No formyltetrahydrofolate synthetase genes affiliating with acetogens or with 'homoacetogen similarity' scores >90% were identified. To further investigate the hydrogenotrophic populations in these cultures and link functional gene information with 16S rRNA gene identity, cultures were subcultured quickly, twice, through medium without exogenous hydrogen, followed by incubation without exogenous hydrogen. Comparison of cultures lacking hydrogen and their parent cultures revealed novel Lachnospiraceae and Ruminococcaceae that diminished in the absence of hydrogen, supporting the hypothesis that they were likely the predominant acetogens in the enrichments. Interestingly, a range of Bacteroidetes rrs sequences that demonstrated <86% identity to any named isolate also diminished in cultures lacking hydrogen. Acetogens or sulphate reducers from the Bacteroidetes have not been reported previously; therefore this observation requires further investigation.

  9. Therapy of Chronic Cardiosclerosis in WAG Rats Using Cultures of Cardiovascular Cells Enriched with Cardiac Stem Cell.

    Chepeleva, E V; Pavlova, S V; Malakhova, A A; Milevskaya, E A; Rusakova, Ya L; Podkhvatilina, N A; Sergeevichev, D S; Pokushalov, E A; Karaskov, A M; Sukhikh, G T; Zakiyan, S M

    2015-11-01

    We developed a protocol for preparing cardiac cell culture from rat heart enriched with regional stem cells based on clonogenic properties and proliferation in culture in a medium with low serum content. Experiments on WAG rats with experimental ischemic myocardial damage showed that implantation of autologous regional stem cells into the left ventricle reduced the volume of cicatricial tissue, promoted angiogenesis in the damaged zone, and prevented the risk of heart failure development.

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

    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 μM) or 10x (700 μM) 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.

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

    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 (NH(4)(+)), and nitrate (NO(3)(-)), 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.

  12. Lack of cardiac differentiation in c-kit-enriched porcine bone marrow and spleen hematopoietic cell cultures using 5-azacytidine

    M.L. Ramirez (Mario); T. McMorrow (Tara); T.M. Sanderson (Thomas M.); C.J. Lancos (C.); Y.-L. Tseng (Y.); D.K.C. Cooper (David); F.J.M.F. Dor (Frank)

    2005-01-01

    textabstractThe adult spleen is a source of early hematopoietic stem cells (HSC). We therefore studied whether culturing spleen or bone marrow (BM) HSC in medium containing 5-azacytidine could induce a cardiac phenotype. c-kit enrichment and depletion of adult pig spleen and BM mononuclear cells wer

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

    Jiang, Y.; Mikova, G.; Kleerebezem, R.; Van der Wielen, L.A.M.; Cuellar Soares, M.C.

    2015-01-01

    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

  14. Stable acetate production in extreme-thermophilic (70ºC) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens

    Zhang, F.; Zhang, Y.; Ding, J.; Dai, K.; Van Loosdrecht, M.C.M.; Zeng, R.J.

    2014-01-01

    The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in extreme-th

  15. Large-scale monocyte enrichment coupled with a closed culture system for the generation of human dendritic cells.

    Pullarkat, Vinod; Lau, Roy; Lee, Sun-Min; Bender, James G; Weber, Jeffrey S

    2002-09-15

    Conventional methods for generating monocyte-derived dendritic cells (DC) for clinical trials utilize the property of plastic adherence to select monocytes from leukapheresis samples. This method is labor-intensive and has the potential for contamination at various steps. We evaluated a large-scale monocyte enrichment procedure using a cell selector (Isolex 300i(R)) followed by culture in a sterile bag system (Stericell(R)) for generation of DC. DC generated in tissue culture flasks after monocyte selection by plastic adherence were compared to those generated in Stericell(R) bags after monocyte enrichment by negative selection with the Isolex(R) 300i. DC were matured with lipopolysaccharide and pulsed with a peptide derived from the melanoma antigen gp100. Peptide-pulsed DC cultured by the two techniques were evaluated for phenotype, viability, ability to induce allogeneic and peptide-specific autologous proliferative responses as well as peptide-specific cytotoxic T-cell responses. The mean monocyte yield from leukapheresis collections was 17+/-2.4%, which increased to 52+/-11% after Isolex(R) selection. The DC yield of plated mononuclear cells from flasks or bags was 2.7+/-0.96% and 4.84+/-2.65%, respectively. DC cultured by both methods expressed high levels of CD86, CD80, CD40, CD83, CD44, CD11c and CD58, and was comparable in their ability to induce allogeneic and peptide-specific autologous proliferative responses as well as gp100 peptide-specific cytotoxic T-cell responses. These results indicate that potent monocyte-derived DC can be generated in a closed culture bag system after monocyte enrichment by immunomagnetic negative selection. Due to the closed nature of the enrichment and culture systems, the potential for contamination is minimized. This protocol is well suited for culturing large numbers of DC for clinical immunotherapy trials.

  16. The culture of cancer cell lines as tumorspheres does not systematically result in cancer stem cell enrichment.

    Calvet, Christophe Y; André, Franck M; Mir, Lluis M

    2014-01-01

    Cancer stem cells (CSC) have raised great excitement during the last decade and are promising targets for an efficient treatment of tumors without relapses and metastases. Among the various methods that enable to enrich cancer cell lines in CSC, tumorspheres culture has been predominantly used. In this report, we attempted to generate tumorspheres from several murine and human cancer cell lines: B16-F10, HT-29, MCF-7 and MDA-MB-231 cells. Tumorspheres were obtained with variable efficiencies from all cell lines except from MDA-MB-231 cells. Then, we studied several CSC characteristics in both tumorspheres and adherent cultures of the B16-F10, HT-29 and MCF-7 cells. Unexpectedly, tumorspheres-forming cells were less clonogenic and, in the case of B16-F10, less proliferative than attached cells. In addition, we did not observe any enrichment in the population expressing CSC surface markers in tumorspheres from B16-F10 (CD133, CD44 and CD24 markers) or MCF-7 (CD44 and CD24 markers) cells. On the contrary, tumorspheres culture of HT-29 cells appeared to enrich in cells expressing colon CSC markers, i.e. CD133 and CD44 proteins. For the B16-F10 cell line, when 1 000 cells were injected in syngenic C57BL/6 mice, tumorspheres-forming cells displayed a significantly lower tumorigenic potential than adherent cells. Finally, tumorspheres culture of B16-F10 cells induced a down-regulation of vimentin which could explain, at least partially, the lower tumorigenicity of tumorspheres-forming cells. All these results, along with the literature, indicate that tumorspheres culture of cancer cell lines can induce an enrichment in CSC but in a cell line-dependent manner. In conclusion, extensive characterization of CSC properties in tumorspheres derived from any cancer cell line or cancer tissue must be performed in order to ensure that the generated tumorspheres are actually enriched in CSC.

  17. Isolation and Physiological Characterization of Psychrophilic Denitrifying Bacteria from Permanently Cold Arctic Fjord Sediments (Svalbard, Norway)

    Canion, Andy; Prakash, Om; Green, Stefan J.; Jahnke, Linda; Kuypers, Marcel M. M.; Kostka, Joel E.

    2013-01-01

    A large proportion of reactive nitrogen loss from polar sediments is mediated by denitrification, but microorganisms mediating denitrification in polar environments remain poorly characterized. A combined approach of most-probable-number (MPN) enumeration, cultivation and physiological characterization was used to describe psychrophilic denitrifying bacterial communities in sediments of three Arctic fjords in Svalbard (Norway). A MPN assay showed the presence of 10(sup 3)-10(sup 6) cells of psychrophilic nitrate-respiring bacteria g(sup -1) of sediment. Fifteen strains within the Proteobacteria were isolated using a systematic enrichment approach with organic acids as electron donors and nitrate as an electron acceptor. Isolates belonged to five genera, including Shewanella, Pseudomonas, Psychromonas (Gammaproteobacteria), Arcobacter (Epsilonproteobacteria) and Herminiimonas (Betaproteobacteria). All isolates were denitrifiers, except Shewanella, which exhibited the capacity for dissimilatory nitrate reduction to ammonium (DNRA). Growth from 0 to 40 degC demonstrated that all genera except Shewanella were psychrophiles with optimal growth below 15 degC, and adaptation to low temperature was demonstrated as a shift from primarily C16:0 saturated fatty acids to C16:1 monounsaturated fatty acids at lower temperatures. This study provides the first targeted enrichment and characterization of psychrophilic denitrifying bacteria from polar sediments, and two genera, Arcobacter and Herminiimonas, are isolated for the first time from permanently cold marine sediments.

  18. Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part A-Monocyclic and Polycyclic Aromatic Hydrocarbons.

    Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

    2015-08-01

    Present study focused on the screening of bacterial consortium for biodegradation of monocyclic aromatic hydrocarbon (MAH) and polycyclic aromatic hydrocarbons (PAHs). Target compounds in the present study were naphthalene, acenaphthene, phenanthrene (PAHs), and benzene (MAH). Microbial consortia enriched with the above target compounds were used in screening experiments. Naphthalene-enriched consortium was found to be the most efficient consortium, based on its substrate degradation rate and its ability to degrade other aromatic pollutants with significantly high efficiency. Substrate degradation rate with naphthalene-enriched culture followed the order benzene > naphthalene > acenaphthene > phenanthrene. Chryseobacterium and Rhodobacter were discerned as the predominant species in naphthalene-enriched culture. They are closely associated to the type strain Chryseobacterium arthrosphaerae and Rhodobacter maris, respectively. Single substrate biodegradation studies with naphthalene (PAH) and benzene (MAH) were carried out using naphthalene-enriched microbial consortium (NAPH). Phenol and 2-hydroxybenzaldehyde were identified as the predominant intermediates during benzene and naphthalene degradation, respectively. Biodegradation of toluene, ethyl benzene, xylene, phenol, and indole by NAPH was also investigated. Monod inhibition model was able to simulate biodegradation kinetics for benzene, whereas multiple substrate biodegradation model was able to simulate biodegradation kinetics for naphthalene.

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

    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.

  20. Survey of Naegleria from Taiwan recreational waters using culture enrichment combined with PCR.

    Huang, Shih-Wei; Hsu, Bing-Mu

    2011-08-01

    Naegleria is a free-living amoeba. Pathogenic Naegleria may pose a health risk to people who come in contact with recreational waters. Here, we used Naegleria culture enrichment with PCR to identify the Naegleria species and investigated the distribution of Naegleria spp. in recreational waters including spring water, stream water and raw domestic water in central and southern Taiwan. In this study, Naegleria spp. were detected in 19 (17.8%) of the water samples. The occurrence of Naegleria in raw domestic water was 28.6%, higher than in stream water (14.7%) and in spring water (6.5%). The most frequently identified species exhibiting the closest phylogenetic relationships to the isolates were N. australiensis (n=4) and N. canariensis (n=4), followed by N. clarki (n=3) and N. philippinensis (n=3); N. americana (n=2). N. lovaniensis, N. dobsoni, and N. gruberi were each detected once. The pathogenic species N. fowleri was not detected, probably due to the low incubation temperature; however, the isolates exhibiting the closest phylogenetic relationships to the pathogenic species in mice of PAM, N. australiensis and N. philippinensis, were found. Results of this survey suggest the distribution of Naegleria spp. excluding N. fowleri in recreational waters. It should be considered a potential threat for health associated with human activities in recreational waters.

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

    Laura Audrey Hug

    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.

  2. Culture and Phosphorus Removal Property of Granular Sludge for Denitrifying Phosphorus Removal%反硝化除磷颗粒污泥的培养与除磷性能

    李军; 张宇坤; 韦甦; 王亚宜; 马骁; 彭永臻

    2012-01-01

    The granular sludge for denitrifying phosphorus removal is successfully formed in a sequencing batch reactor (SBR) fed with synthetic wastewater, by controlling the operational modes of anaerobic/ anoxic/aerobic, anoxie addition of the nitrate, and selection pressure. The granular sludge turns into ashape with a diameter of 0.3 to 0.5 mm, and sludge volume index (SVI) and mixed solid (MLSS) are maintained at 45 mL/g and 4 000 rag/L, respectively, during the The granular sludge for the denitrifying phosphorus removal also shows a good nutrient re steady moval suspended operation. capability,with the COD, ammonia nitrogen and phosphorus removal effieiencies of 88%, 96% and 90%, respectively. The fate of phosphorus and the X-ray diffraction test results suggest the existence of granular sludge phosphate precipitation phosphorus removal phenomena. Granular sludge for the denitrifyingphosphorus removal in the experiment uses biological phosphorus removal, and it also has phosphorus removal through phosphate precipitation in granular sludge.%摘要:以普通絮状污泥为接种污泥,人工配制生活污水,采用厌氧/缺氧/好氧的运行方式,通过在缺氧段投加硝酸盐氮和控制选择压,经98d的培养与调整在SBR中获得具有反硝化除磷功能的颗粒污泥.稳定运行的颗粒污泥粒径主要在0.3-0.5mm,SVI约为45mL/g,p(MLSS)约为4000mg/L.具有反硝化除磷功能的颗粒污泥对COD、氨氮和磷酸盐的去除率分别可达88%、96%和90%.通过分析磷的去向及X射线衍射检测结果可知存在颗粒污泥的磷酸盐沉淀除磷现象.培养的反硝化除磷颗粒污泥除生物除磷外,还具有磷酸盐固化于污泥颗粒方式除磷。

  3. Continuous culture enrichments of ammonia-oxidizing bacteria at low ammonium concentrations

    Bollmann, A.; Laanbroek, H.J.

    2001-01-01

    Until now enrichments of ammonia-oxidizing bacteria from natural ammonium-limited environments have been performed mainly in the presence of much higher ammonia concentrations than those present in the natural environment and many have resulted in the enrichment and isolation of environmentally less

  4. Enrichment culture and molecular identification of diverse Bartonella species in stray dogs.

    Bai, Ying; Kosoy, Michael Y; Boonmar, Sumalee; Sawatwong, Pongpun; Sangmaneedet, Somboon; Peruski, Leonard F

    2010-12-15

    Using pre-enrichment culture in Bartonella alpha-Proteobacteria growth medium (BAPGM) followed by PCR amplification and DNA sequence identification that targeted a fragment of the citrate synthase gene (gltA), we provide evidence of common bartonella infections and diverse Bartonella species in the blood of stray dogs from Bangkok and Khon Kaen, Thailand. The overall prevalence of all Bartonella species was 31.3% (60/192), with 27.9% (31/111) and 35.8% (29/81) in the stray dogs from Bangkok and Khon Kaen, respectively. Phylogenetic analyzes of gltA identified eight species/genotypes of Bartonella in the blood of stray dogs, including B. vinsonii subsp. arupensis, B. elizabethae, B. grahamii, B. quintana, B. taylorii, and three novel genotypes (BK1, KK1 and KK2) possibly representing unique species with ≤ 90.2% similarities to any of the known Bartonella species B. vinsonii subsp. arupensis was the only species detected in dogs from both sites, B. quintana and BK1 were found in the dogs from Bangkok, B. elizabethae, B. taylorii, KK1 and KK2 were found in the dogs from Khon Kaen. We conclude that stray dogs in Thailand are frequently infected with Bartonella species that vary with geographic region. As some Bartonella species detected in the present study are considered pathogenic for humans, stray dogs in Thailand may serve as possible reservoirs for Bartonella causing human illnesses. Further work is needed to determine the role of those newly discovered Bartonella genotypes/species in human and veterinary medicine.

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

    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, α- and γ-Proteobacteria and Actinobacteria were present at initial steps of enrichment whereas β-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.

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

    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.

  7. Potential effect of matrix stiffness on the enrichment of tumor initiating cells under three-dimensional culture conditions.

    Liu, Chang; Liu, Yang; Xu, Xiao-xi; Wu, Hao; Xie, Hong-guo; Chen, Li; Lu, Ting; Yang, Li; Guo, Xin; Sun, Guang-wei; Wang, Wei; Ma, Xiao-jun; He, Xin

    2015-01-01

    Cancer stem cell (CSC) or tumor initiating cell (TIC) plays an important role in tumor progression and metastasis. Biophysical forces in tumor microenvironment have an important effect on tumor formation and development. In this study, the potential effect of matrix stiffness on the biological characteristics of human head and neck squamous cell carcinoma (HNSCC) TICs, especially the enrichment of HNSCC TICs, was investigated under three-dimensional (3D) culture conditions by means of alginate gel (ALG) beads with different matrix stiffnesses. ALG beads with soft (21 kPa), moderate (70 kPa) and hard (105 kPa) stiffness were generated by changing alginate concentration. It was found that significant HNSCC TIC enrichment was achieved in the ALG beads with moderate matrix stiffness (70 kPa). The gene expression of stemness markers Oct3/4 and Nanog, TIC markers CD44 and ABCG2 was enhanced in cells under this moderate (70 kPa) stiffness. HNSCC TIC proportion was also highly enriched under moderate matrix stiffness, accompanying with higher tumorigenicity, metastatic ability and drug resistance. And it was also found that the possible molecular mechanism underlying the regulated TIC properties by matrix stiffness under 3D culture conditions was significantly different from 2D culture condition. Therefore, the results achieved in this study indicated that 3D biophysical microenvironment had an important effect on TIC characteristics and alginate-based biomimetic scaffolds could be utilized as a proper platform to investigate the interaction between tumor cells and 3D microenvironment.

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

    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

  9. The culture of cancer cell lines as tumorspheres does not systematically result in cancer stem cell enrichment.

    Christophe Y Calvet

    Full Text Available Cancer stem cells (CSC have raised great excitement during the last decade and are promising targets for an efficient treatment of tumors without relapses and metastases. Among the various methods that enable to enrich cancer cell lines in CSC, tumorspheres culture has been predominantly used. In this report, we attempted to generate tumorspheres from several murine and human cancer cell lines: B16-F10, HT-29, MCF-7 and MDA-MB-231 cells. Tumorspheres were obtained with variable efficiencies from all cell lines except from MDA-MB-231 cells. Then, we studied several CSC characteristics in both tumorspheres and adherent cultures of the B16-F10, HT-29 and MCF-7 cells. Unexpectedly, tumorspheres-forming cells were less clonogenic and, in the case of B16-F10, less proliferative than attached cells. In addition, we did not observe any enrichment in the population expressing CSC surface markers in tumorspheres from B16-F10 (CD133, CD44 and CD24 markers or MCF-7 (CD44 and CD24 markers cells. On the contrary, tumorspheres culture of HT-29 cells appeared to enrich in cells expressing colon CSC markers, i.e. CD133 and CD44 proteins. For the B16-F10 cell line, when 1 000 cells were injected in syngenic C57BL/6 mice, tumorspheres-forming cells displayed a significantly lower tumorigenic potential than adherent cells. Finally, tumorspheres culture of B16-F10 cells induced a down-regulation of vimentin which could explain, at least partially, the lower tumorigenicity of tumorspheres-forming cells. All these results, along with the literature, indicate that tumorspheres culture of cancer cell lines can induce an enrichment in CSC but in a cell line-dependent manner. In conclusion, extensive characterization of CSC properties in tumorspheres derived from any cancer cell line or cancer tissue must be performed in order to ensure that the generated tumorspheres are actually enriched in CSC.

  10. Effect of free ammonia and free nitrous acid concentration on the anabolic and catabolic processes of an enriched Nitrosomonas culture.

    Vadivelu, Vel M; Keller, Jurg; Yuan, Zhiguo

    2006-12-05

    The effects of free ammonia (FA; NH(3)) and free nitrous acid (FNA; HNO(2)) concentrations on the metabolisms of an enriched ammonia oxidizing bacteria (AOB) culture were investigated using a method allowing the decoupling of growth and energy generation processes. A lab-scale sequencing batch reactor (SBR) was operated for the enrichment of an AOB culture. Fluorescent in-situ hybridization (FISH) analysis showed that 82% of the bacterial population in the SBR bound to the NEU probe specifically designed for Nitrosomonas europaea. Batch tests were carried out to measure the oxygen and ammonium consumption rates by the culture at various FA and FNA levels, in the presence or absence of inorganic carbon (CO(2), HCO(3) (-), and CO(3) (2-)). It was revealed that FA of up to 16.0 mgNH(3)-N . L(-1), which was the highest concentration used in this study, did not have any inhibitory effect on either the catabolic or anabolic processes of the Nitrosomonas culture. In contrast, FNA inhibited both the growth and energy production capabilities of the Nitrosomonas culture. The inhibition on growth initiated at approximately 0.10 mgHNO(2)-N . L(-1), and the data suggested that the biosynthesis was completely stopped at an FNA concentration of 0.40 mgHNO(2)-N . L(-1). The inhibition on energy generation initiated at a slightly lower level but the Nitrosomonas culture was still oxidizing ammonia at half of the maximum rate at an FNA concentration of 0.50-0.63 mgHNO(2)-N . L(-1). The affinity constant of the Nitrosomonas culture with respect to ammonia was determined to be 0.36 mgNH(3)-N . L(-1), independent of the presence or absence of inorganic carbon.

  11. Screening and identification of aerobic denitrifiers

    Shao, K.; Deng, H. M.; Chen, Y. T.; Zhou, H. J.; Yan, G. X.

    2016-08-01

    With the standards of the effluent quality more stringent, it becomes a quite serious problem for municipalities and industries to remove nitrogen from wastewater. Bioremediation is a potential method for the removal of nitrogen and other pollutants because of its high efficiency and low cost. Seven predominant aerobic denitrifiers were screened and characterized from the activated sludge in the CAST unit. Some of these strains removed 87% nitrate nitrogen at least. Based on their phenotypic and phylogenetic characteristics, the isolates were identified as the genera of Ralstonia, Achromobacter, Aeromonas and Enterobacter.

  12. IDENTIFICATION AND ECOPHYSIOLOGY OF ACTIVE DENITRIFIERS IN ACTIVATED SLUDGE

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

    and when external carbon sources were supplemented to the activated sludge the composition of the denitrifying communities was significantly affected. Transcriptome profiling provided detailed insight in the metabolic pathways in several of the active denitrifiers in activated sludge. In conclusion...... 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 expressed denitrification genes (nirS, nirK and nosZ) upon various substrate-inductions. To come around...... were determined with quantitative FISH, while their active metabolic pathways were investigated directly in activated sludge with a tag-based metatranscriptomic approach under acetate-utilizing and denitrifying conditions. The different methods revealed a majority of denitrifiers in all WWTPs belonging...

  13. Improved enrichment culture technique for methane-oxidizing bacteria from marine ecosystems: the effect of adhesion material and gas composition.

    Vekeman, Bram; Dumolin, Charles; De Vos, Paul; Heylen, Kim

    2017-02-01

    Cultivation of microbial representatives of specific functional guilds from environmental samples depends largely on the suitability of the applied growth conditions. Especially the cultivation of marine methanotrophs has received little attention, resulting in only a limited number of ex situ cultures available. In this study we investigated the effect of adhesion material and headspace composition on the methane oxidation activity in methanotrophic enrichments obtained from marine sediment. Addition of sterilized natural sediment or alternatively the addition of acid-washed silicon dioxide significantly increased methane oxidation. This positive effect was attributed to bacterial adhesion on the particles via extracellular compounds, with a minimum amount of particles required for effect. As a result, the particles were immobilized, thus creating a stratified environment in which a limited diffusive gas gradients could build up and various microniches were formed. Such diffusive gas gradient might necessitate high headspace concentrations of CH4 and CO2 for sufficient concentrations to reach the methane-oxidizing bacteria in the enrichment culture technique. Therefore, high concentrations of methane and carbon dioxide, in addition to the addition of adhesion material, were tested and indeed further stimulated methane oxidation. Use of adhesion material in combination with high concentrations of methane and carbon dioxide might thus facilitate the cultivation and subsequent enrichment of environmentally important members of this functional guild. The exact mechanism of the observed positive effects on methane oxidation and the differential effect on methanotrophic diversity still needs to be explored.

  14. The Control of Microcystis spp. Bloom by Combining Indigenous Denitrifying Bacteria From Sutami Reservoir with Fimbristylis globulosa and Vetiveria zizanoides

    Bayu Agung Prahardika

    2013-04-01

    Full Text Available The purpose of this research is to know the ability of polyculture macrophyte (Fimbristylis globulosa and Vetiveria zizanoides and the combination of both with consortium of indigenous denitrifying bacteria from Sutami reservoir that was added by Microcystis spp. or not to reduce the concentration of nitrate, dissolved phosphate and the carrying capacity of Microcystis spp. The experiment was done in a medium filled up with Sutami reservoir water enriched with 16 ppm of nitrate and 0.4 ppm of phosphate. The denitrifying bacteria used in this research were DR-14, DU-27-1, DU-30-1, DU-30-2, TA-8 and DU-27-4 isolated from Sutami reservoir. The treatments were incubated within 15 days. Microcystis spp. abundance was calculated every day, but the measurement of the concentration of nitrate and dissolved phosphate was done every six days. The results showed that both treatment and the combination of both macrophytes with a consortium of denitrifying indigenous bacteria were added or not either Microcystis able to reduce nitrate at 99% and 93-99% orthophosphoric. The combination of macrophytes with denitrifying indigenous bacterial consortium from Sutami reservoir was able to inhibit the carrying capacity of Microcystis spp. highest up to 47.87%. They could also significantly reduce the abundance of Microcystis from 107 cells/mL in earlier days of the treatment into 0.35x104 cells/mL after fifteen days of incubation.

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

    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)

  16. Proteomic characterization of golgi membranes enriched from Arabidopsis suspension cell cultures

    Hansen, Sara Fasmer; Ebert, Berit; Rautengarten, Carsten

    2016-01-01

    The plant Golgi apparatus has a central role in the secretory pathway and is the principal site within the cell for the assembly and processing of macromolecules. The stacked membrane structure of the Golgi apparatus along with its interactions with the cytoskeleton and endoplasmic reticulum has...... historically made the isolation and purification of this organelle difficult. Density centrifugation has typically been used to enrich Golgi membranes from plant microsomal preparations, and aside from minor adaptations, the approach is still widely employed. Here we outline the enrichment of Golgi membranes...

  17. Biosynthesis of highly enriched 13C-lycopene for human metabolic studies using repeated batch tomato cell culturing with 13C-glucose

    Moran, Nancy E.; Rogers, Randy B.; Lu, Chi-Hua; Conlon, Lauren E.; Lila, Mary Ann; Clinton, Steven K.; Erdman, John W

    2013-01-01

    While putative disease-preventing lycopene metabolites are found in both tomato (Solanum lycopersicum) products and in their consumers, mammalian lycopene metabolism is poorly understood. Advances in tomato cell culturing techniques offer an economical tool for generation of highly-enriched 13C-lycopene for human bioavailability and metabolism studies. To enhance the 13C-enrichment and yields of labeled lycopene from the hp-1 tomato cell line, cultures were first grown in 13C-glucose media fo...

  18. Effects of carbon sources on the enrichment of halophilic polyhydroxyalkanoate-storing mixed microbial culture in an aerobic dynamic feeding process

    Cui, You-Wei; Zhang, Hong-Yu; Lu, Peng-Fei; Peng, Yong-Zhen

    2016-08-01

    Microbial polyhydroxyalkanoate (PHA) production serves as a substitute for petroleum-based plastics. Enriching mixed microbial cultures (MMCs) with the capacity to store PHA is a key precursor for low-cost PHA production. This study investigated the impact of carbon types on enrichment outcomes. Three MMCs were separately fed by acetate sodium, glucose, and starch as an enriching carbon source, and were exposed to long-term aerobic dynamic feeding (ADF) periods. The PHA production capacity, kinetics and stoichiometry of the enrichments, the PHA composition, and the microbial diversity and community composition were explored to determine carbon and enrichment correlations. After 350-cycle enriching periods under feast-famine (F-F) regimes, the MMCs enriched by acetate sodium and glucose contained a maximum PHA content of 64.7% and 60.5% cell dry weight (CDW). The starch-enriched MMC only had 27.3% CDW of PHA. High-throughput sequencing revealed that non-PHA bacteria survived alongside PHA storing bacteria, even under severe F-F selective pressure. Genus of Pseudomonas and Stappia were the possible PHA accumulating bacteria in acetate-enriched MMC. Genus of Oceanicella, Piscicoccus and Vibrio were found as PHA accumulating bacteria in glucose-enriched MMC. Vibrio genus was the only PHA accumulating bacteria in starch-enriched MMC. The community diversity and composition were regulated by the substrate types.

  19. Effects of CO2 enrichment and nutrients supply intermittency on batch cultures of Isochrysis galbana.

    Picardo, Marta C; de Medeiros, José Luiz; Araújo, Ofélia de Queiroz F; Chaloub, Ricardo Moreira

    2013-09-01

    Aiming at enhanced performance to increase economic feasibility of microalgae based processes, Isochrysis galbana was grown in three modes of cultivation: batch, intermittent fed batch and semi-continuous. The batch mode was conducted under two regimes of aeration: conventional aeration and CO2 enriched aeration (5% v/v in air). Increased biomass productivity without significant impact on lipid accumulation was observed for CO2 enriched aeration relatively to cultivation aerated with air only. The intermittent fed batch cultivation policy was proven to be useful for lipid accumulation, increasing the lipid content by 19.8%. However, the semi-continuous mode resulted in higher productivity due to increased biomass concentration; the biomass productivity reached 0.51 g/(Ld). Fluorescence measurements were performed; the calculated low electron transport rate showed the need to increase the irradiance. The results showed that I. galbana can be grown in semi-continuous condition at high levels of biomass productivity.

  20. Microbial succession in response to pollutants in batch-enrichment culture

    Shuo Jiao; Weimin Chen; Entao Wang; Junman Wang; Zhenshan Liu; Yining Li; Gehong Wei

    2016-01-01

    As a global problem, environmental pollution is an important factor to shape the microbial communities. The elucidation of the succession of microbial communities in response to pollutants is essential for developing bioremediation procedures. In the present study, ten batches of soil-enrichment subcultures were subjected to four treatments: phenanthrene, n-octadecane, phenanthrene + n-octadecane, or phenanthrene + n-octadecane + CdCl2. Forty pollutant-degrading consortia, corresponding to ea...

  1. Microbial succession in response to pollutants in batch-enrichment culture.

    Jiao, Shuo; Chen, Weimin; Wang, Entao; Wang, Junman; Liu, Zhenshan; Li, Yining; Wei, Gehong

    2016-02-24

    As a global problem, environmental pollution is an important factor to shape the microbial communities. The elucidation of the succession of microbial communities in response to pollutants is essential for developing bioremediation procedures. In the present study, ten batches of soil-enrichment subcultures were subjected to four treatments: phenanthrene, n-octadecane, phenanthrene + n-octadecane, or phenanthrene + n-octadecane + CdCl2. Forty pollutant-degrading consortia, corresponding to each batch of the four treatments were obtained. High-throughput sequencing of the 16S rRNA gene revealed that the diversity, richness and evenness of the consortia decreased throughout the subculturing procedure. The well-known hydrocarbon degraders Acinetobacter, Gordonia, Sphingobium, Sphingopyxis, and Castellaniella and several other genera, including Niabella and Naxibacter, were detected in the enriched consortia. The predominant microbes varied and the microbial community in the consortia gradually changed during the successive subculturing depending on the treatment, indicating that the pollutants influenced the microbial successions. Comparison of the networks in the treatments indicated that organic pollutants and CdCl2 affected the co-occurrence patterns in enriched consortia. In conclusion, single environmental factors, such as the addition of nutrients or selection pressure, can shape microbial communities and partially explain the extensive differences in microbial community structures among diverse environments.

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

    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…

  3. Signatures of Autotrophic and Heterotrophic Metabolic Activity in Enrichment Cultures from a Sulphur Oxidizing Acid Mine Site

    Slater, G. F.; Bernier, L.; Cowie, B. R.; Warren, L. A.

    2006-12-01

    Delineating the role of microorganisms in geochemical processes of interest in natural environments requires the development of tools that provide the ability to distinguish amongst microbial activity associated with different metabolic guilds. The gap between phylogenetic characterization and phenotypic understanding remains, underscoring the need to consider alternative methods. Compound specific analysis of cellular components has the potential to differentiate between active metabolic processes supporting microbial communities and may be especially useful in extreme environments. The goal of this study was to determine whether the phospholipids fatty acid (PLFA) distribution and isotopic signatures associated with autotrophs and heterotrophs enriched from an acid mine drainage (AMD) system differed, and further whether natural consortial autotrophic isolates showed similar signatures to autotrophic pure strains of Acidithiobacillus ferrooxidans and A. thiooxidans. Two distinct initial enrichments with tetrathionate and CO2 yielded primarily autotrophic (95%) Acidithiobaccillus spp. sulphur oxidizing communities. The remaining microbial members of theses enrichments (subculture of the consortial isolates in a medium amended with glucose but without tetrathionate selectively resulted in their visible growth. PLFA profiles and δ13C signatures from autotrophic (1) natural enrichments, pure cultures of (2) A. ferrooxidans and (3) A. thiooxidans were similar, but collectively differed from those of the natural heterotrophic enrichment cultures. The PLFA profiles for the heterotrophic communities were made up of primarily (88-99%) C16:0 and two isomers of C18:1. In contrast, the autotrophic communities had high proportions of C16:1 (up to 18%) as well as cyclo C17 and cyclo C19 PLFA that combined comprised 18 to 58% of the observed PLFA. The δ13C signatures of the PLFA also differed strongly between the two trophic levels. The δ13C of the autotrophic PLFA, - 24 to

  4. mRNA differential display in a microbial enrichment culture: simultaneous identification of three cyclohexanone monooxygenases from three species.

    Brzostowicz, Patricia C; Walters, Dana M; Thomas, Stuart M; Nagarajan, Vasantha; Rouvière, Pierre E

    2003-01-01

    mRNA differential display has been used to identify cyclohexanone oxidation genes in a mixed microbial community derived from a wastewater bioreactor. Thirteen DNA fragments randomly amplified from the total RNA of an enrichment subculture exposed to cyclohexanone corresponded to genes predicted to be involved in the degradation of cyclohexanone. Nine of these DNA fragments are part of genes encoding three distinct Baeyer-Villiger cyclohexanone monooxygenases from three different bacterial species present in the enrichment culture. In Arthrobacter sp. strain BP2 and Rhodococcus sp. strain Phi2, the monooxygenase is part of a gene cluster that includes all the genes required for the degradation of cyclohexanone, while in Rhodococcus sp. strain Phi1 the genes surrounding the monooxygenase are not predicted to be involved in this degradation pathway but rather seem to belong to a biosynthetic pathway. Furthermore, in the case of Arthrobacter strain BP2, three other genes flanking the monooxygenase were identified by differential display, demonstrating that the repeated sampling of bacterial operons shown earlier for a pure culture (D. M. Walters, R. Russ, H. Knackmuss, and P. E. Rouvière, Gene 273:305-315, 2001) is also possible for microbial communities. The activity of the three cyclohexanone monooxygenases was confirmed and characterized following their expression in Escherichia coli.

  5. Spontaneous bacterial peritonitis due to Listeria monocytogenes: importance of enrichment culture.

    Jayasinghe, Saroj; Connor, Martin; Donaldson, Shona; Austin, Hannah; Foster, Adele

    2010-09-01

    A case of Listeria monocytogenes induced spontaneous bacterial peritonitis (SBP) is reported in a patient with primary biliary cirrhosis. It is an indolent illness and may not show a neutrophil reaction in peritoneal fluid. Enrichment broth was required to isolate L monocytogenes in the patient. This is not routinely used in the UK and therefore isolates may be missed. L monocytogenes remains sensitive to ampicillin, penicillin and gentamicin, but is resistant to cephalosporin antibiotics. The rising incidence of listeriosis in the population suggests that the incidence of SBP from L monocytogenes is likely to increase.

  6. Developments in techniques for the isolation, enrichment, main culture conditions and identification of spermatogonial stem cells

    He, Yanan; Chen, Xiaoli; Zhu, Huabin; Wang, Dong

    2015-01-01

    The in vitro culture system of spermatogonial stem cells (SSCs) provides a basis for studies on spermatogenesis, and also contributes to the development of new methods for the preservation of livestock and animal genetic modification. In vitro culture systems have mainly been established for mouse SSCs, but are lacking for farm animals. We reviewed and analyzed the current progress in SSC techniques such as isolation, purification, cultivation and identification. Based on the published studie...

  7. Culturing bias in marine heterotrophic flagellates analyzed through seawater enrichment incubations.

    del Campo, Javier; Balagué, Vanessa; Forn, Irene; Lekunberri, Itziar; Massana, Ramon

    2013-10-01

    The diversity of heterotrophic flagellates is generally based on cultivated strains, on which ultrastructural, physiological, and molecular studies have been performed. However, the relevance of these cultured strains as models of the dominant heterotrophic flagellates in the marine planktonic environment is unclear. In fact, molecular surveys typically recover novel eukaryotic lineages that have refused cultivation so far. This study was designed to directly address the culturing bias in planktonic marine heterotrophic flagellates. Several microcosms were established adding increasing amounts and sources of organic matter to a confined natural microbial community pre-filtered by 3 μm. Growth dynamics were followed by epifluorescence microscopy and showed the expected higher yield of bacteria and heterotrophic flagellates at increased organic matter additions. Moreover, protist diversity analyzed by molecular tools showed a clear substitution in the community, which differed more and more from the initial sample as the organic matter increased. Within this gradient, there was also an increase of sequences related to cultured organisms as well as a decrease in diversity. Culturing bias is partly explained by the use of organic matter in the isolation process, which drives a shift in the community to conditions closer to laboratory cultures. An intensive culturing effort using alternative isolation methods is necessary to allow the access to the missing heterotrophic flagellates that constitute the abundant and active taxa in marine systems.

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

    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 μg/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 μg/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.

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

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

    2013-12-01

    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. Nine cultures JS01.Deg01 to JS09.Deg01 were identified as the degrader of atrazine in the enrichment culture. The three isolates JS04.Deg01, JS07.Deg01, and JS08.Deg01 were identified as efficient atrazine metabolizers. Isolates JS04.Deg01 and JS07.Deg01 produced hydroxyatrazine (HA) N-isopropylammelide and cyanuric acid by dealkylation reaction. The isolate JS08.Deg01 generated deethylatrazine (DEA), deisopropylatrazine (DIA), and cyanuric acid by N-dealkylation in the upper degradation pathway and later it incorporated cyanuric acid in their biomass by the lower degradation pathway. The optimum pH for degrading atrazine by JS08.Deg01 was 7.0 and 16S rDNA phylogenetic typing identified it as Enterobacter cloacae strain JS08.Deg01. The highest atrazine mineralization was observed in case of isolate JS08.Deg01, where an ample amount of trzD mRNA was quantified at 72 h of incubation with atrazine. Atrazine bioremediating isolate E. cloacae strain JS08.Deg01 could be the better environmental remediator of agricultural soils and the crop fields contaminated with atrazine could be the source of the efficient biodegrading microbial strains for the environmental cleanup process.

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

    Robinson David Jebakumar SOLOMON; Amit KUMAR; Velayudhan SATHEEJA SANTHI

    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 microor-ganisms. This study provides information on the occurrence of atrazine mineralizing bacterial strains with faster me-tabolizing ability. The enrichment cultures were tested for the biodegradation of atrazine by high-performance liquid chromatography (HPLC) and mass spectrometry. Nine cultures JS01.Deg01 to JS09.Deg01 were identified as the degrader of atrazine in the enrichment culture. The three isolates JS04.Deg01, JS07.Deg01, and JS08.Deg01 were identified as efficient atrazine metabolizers. Isolates JS04.Deg01 and JS07.Deg01 produced hydroxyatrazine (HA) N-isopropylammelide and cyanuric acid by dealkylation reaction. The isolate JS08.Deg01 generated deethylatrazine (DEA), deisopropylatrazine (DIA), and cyanuric acid by N-dealkylation in the upper degradation pathway and later it incorporated cyanuric acid in their biomass by the lower degradation pathway. The optimum pH for degrading atrazine by JS08.Deg01 was 7.0 and 16S rDNA phylogenetic typing identified it as Enterobacter cloacae strain JS08.Deg01. The highest atrazine mineralization was observed in case of isolate JS08.Deg01, where an ample amount of trzD mRNA was quantified at 72 h of incubation with atrazine. Atrazine bioremediating isolate E. cloacae strain JS08.Deg01 could be the better environmental remediator of agricultural soils and the crop fields contaminated with atrazine could be the source of the efficient biodegrading microbial strains for the environmental cleanup process.

  11. Lactate induces tumour necrosis factor-alpha, interleukin-6 and interleukin-1beta release in microglial- and astroglial-enriched primary cultures.

    Andersson, Anna K; Rönnbäck, Lars; Hansson, Elisabeth

    2005-06-01

    Hyperammonaemia has deleterious effects on the CNS in patients with liver dysfunction. Cellular mechanisms underlying the effects of hyperammonaemia are largely unknown, although astrocytes have been the main target of interest. This study investigated how treatment with NH4Cl and lactate, which increase in the brain as a consequence of hyperammonaemia, affects cells in primary rat cultures enriched in either astrocytes or microglia. Morphological changes were studied over time using light microscopy. Release of the proinflammatory cytokines tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 and IL-1beta was measured using ELISA. NH4Cl was found to induce vacuole formation in both culture systems. Lactate treatment altered astrocytic appearance, resulting in increased space between individual cells. Microglia adopted a round morphology with either NH4Cl or lactate treatment. Lactate, but not NH4Cl, induced release of TNF-alpha and IL-6 in both astroglial- and microglial-enriched cultures, while IL-1beta was released only in microglial cultures. Cytokine release was higher in the microglial- than in the astroglial-enriched cultures. Additionally, the astroglial-enriched cultures containing approximately 10% microglial cells released more cytokines than cultures containing about 5% microglial cells. Taken together, our data suggest that most TNF-alpha, IL-6 and IL-1beta release comes from microglia. Thus, microglia could play an important role in the pathological process of hyperammonaemia.

  12. One health from a social-ecological systems perspective: enriching social and cultural dimensions.

    Ross, Helen

    2013-01-01

    This chapter offers insights from the environmental management paradigm of 'social-ecological systems' and related bodies of theory on people-environment relationships to assist the evolution of the One Health interdisciplinary endeavour of health promotion across human-animal ecosystem relationships. It also seeks to expand thinking about the social and cultural dimensions that are likely to prove important in the development of thinking and practice in the One Health field. It advocates consideration of cultural and economic relationships affecting people's interactions with domesticated and wild animal species and ecosystems, and exploration of the cognitive and behavioural aspects of these interactions.

  13. Biodegradation of Chlorpyrifos by Pseudomonas Resinovarans Strain AST2.2 Isolated from Enriched Cultures.

    Anish Sharma*,

    2016-04-01

    Full Text Available A bacterial strain AST2.2 with chlorpyrifos degrading ability was isolated by enrichment technique from apple orchard soil with previous history of chlorpyrifos use. Based on the morphological, biochemical tests and 16S rRNA sequence analysis, AST2.2 strain was identified as Pseudomonas resinovarans. The strain AST2.2 utilized chlorpyrifos as the sole source of carbon and energy. This strain exhibited growth upto 400mg/l concentration of chlorpyrifos and exhibited high extracellular organophosphorus hydrolase (OPH activity. Gas chromatography-flame ionization detector (GC-FID studies revealed that Pseudomonas resinovarans AST2.2 degraded 43.90 % of chlorpyrifos (400 mg/l within 96 hrs. Intermediates of chlorpyrifos degradation were identified using GC-MS. This strain have potential to degrade chlorpyrifos and thus can be used for bioremediation and ecological restoration of sites contaminated with chlorpyrifos.

  14. Real-time PCR detection of Campylobacter spp.: A comparison toclassic culturing and enrichment

    Boer, P. de; Rahaoui, H.; Leer, R.J.; Montijn, R.C.; Vossen, J.M.B.M. van der

    2015-01-01

    The major disadvantage of the current gold standard for detection of the food pathogen Campylobacter, i.e. culturing, is the lengthy procedure. In this study we assessed the use of real-time PCR for detection of Campylobacter. To this end, 926 poultry samples, taken from transport containers and bro

  15. Culturally Diverse Literature: Enriching Variety in an Era of Common Core State Standards

    Boyd, Fenice B.; Causey, Lauren L.; Galda, Lee

    2015-01-01

    The authors argue for the overwhelming importance of finding and including culturally diverse literature into the curricula teachers are authorized to teach. They discuss the implications of use and offer ideas on how to identify quality literature to include in classroom and school libraries.

  16. Effects of Culture Media and Light Intensity on in vitro Growth of Oncidium under CO2 Enrichment Condition

    He Songlin; Pan Huitang; Yang Qiusheng; Kong Dezheng; Zhang Qixiang; Michio Tanaka

    2003-01-01

    The effects of culture media and light intensity on in vitro growth of Oncidium 'Aloha Iwanga' were investigated under CO2 enrichment condition. Height, fresh and dry weight of the Oncidium seedlings were measured, and the leaf number per plant, shoot number per plant, leaf width and leaf chlorophyll content were also investigated. The results were as follows: 1) The seedling height, fresh and dry weight, leaf number per plant, leaf width and leaf chlorophyll content of the shoots growing on MS complete culture medium were higher than those on 1/2MS, VW and 1/2VW media. The root number per plant and ratio of dry matter of the seedlings cultured on 1/2MS and 1/2VW media were higher than those on MS and VW; 2) The seedling height, fresh weight, dry weight, dry matter ratio and leaf chlorophyll content, leaf length, leaf width, root length, leaf number per plant, root number per plant of seedlings of Oncidium growing under 4 500 lx and 1 700 lx were higher than those under 750 lx. However, there was no significant difference in those growth parameters mentioned above while dealing with 4 500 lx and 1 700 lx except for the seedling height. Nevertheless, the leaf color of plants under 4 500 lx was lighter and the leaves of the lower parts became yellowish in comparison with those growing under 1 700 lx.

  17. Stable acetate production in extreme-thermophilic (70°C) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens

    Zhang, Fang; Zhang, Yan; Ding, Jing; Dai, Kun; van Loosdrecht, Mark C. M.; Zeng, Raymond J.

    2014-06-01

    The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in extreme-thermophilic (70°C) mixed culture fermentation. The continuous stirred tank reactor (CSTR) was stable operated during 100 days, in which acetate accounted for more than 90% of metabolites in liquid solutions. The yields of acetate, methane and biomass in CSTR were 1.5 +/- 0.06, 1.0 +/- 0.13 and 0.4 +/- 0.05 mol/mol glucose, respectively, close to the theoretical expected values. The CSTR effluent was stable and no further conversion occurred when incubated for 14 days in a batch reactor. In fed-batch experiments, acetate could be produced up to 34.4 g/L, significantly higher than observed in common hydrogen producing fermentations. Acetate also accounted for more than 90% of soluble products formed in these fed-batch fermentations. The microbial community analysis revealed hydrogenotrophic methanogens (mainly Methanothermobacter thermautotrophicus and Methanobacterium thermoaggregans) as 98% of Archaea, confirming that high temperature will select hydrogenotrophic methanogens over aceticlastic methanogens effectively. This work demonstrated a potential application to effectively produce acetate as a value chemical and methane as an energy gas together via mixed culture fermentation.

  18. Nicotine suppresses lipopolysaccharide-induced release of interleukin-6 in mixed glia and microglia-enriched cultures

    Zhihua Li; Qingzan Zhao; Hua Zhang; Xiuhua Ren; Mingfu Zhou; Weidong Zang

    2011-01-01

    Inflammation plays an important role in the pathogenesis of Parkinson's disease (PD) through the over-activation of microglia.Epidemiological studies show that smoking is associated with a lower incidence of PD.This study hypothesized that the neuroprotective effect of nicotine is mediated by modulating the activation of microglia via cytokine release.This study found that nicotine pretreatment suppressed the lipopolysaccharide-induced inflammatory reaction in the nervous system, especially microglia activation and interleukin-6 production.The inhibitory effects of 100 pmol/L nicotine were stronger compared with 1 and 10 pmol/L nicotine.These findings indicate that nicotine significantly decreases the production of proinflammatory interleukin-6 in mixed glia or microglia-enriched cultures, and plays an inhibitory effect on the lipopolysaccharide-induced inflammatory reaction.

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

    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.

  20. Identification and Metabolic Mechanism of Non-fermentative Short-cut Denitrifying Phosphorus-removing Bacteria

    LIU Hui; SUN Yanfu; JIA Xiaoshan; LI Jun; ZHOU Kangqun; QU Xiangdong; TAO Xueqin

    2013-01-01

    To investigate the characteristics and metabolic mechanism of short-cut denitrifying phosphorus-removing bacteria (SDPB) that are capable of enhanced biological phosphorus removal (EBPR) using nitrite as an electron acceptor,an aerobic/anoxic sequencing batch reactor was operated under three phases.An SDPB-strain YC was screened after the sludge enrichment and was identified by morphological,physiological,biochemical properties and 16S rDNA gene sequence analysis.Denitrifying phosphorus-removing experiments were conducted to study anaerobic and anoxic metabolic mechanisms by analyzing the changes of chemical oxygen demand (COD),phosphate,nitrite,poly-fβ-hydroxybutyrate (PHB),and glycogen.The results show that strain YC is a non-fermentative SDPB similar to Paracoccus denitrificans.As a kind of non-fermentative bacteria,the energy of strain YC was mainly generated from phosphorus release (96.2%) under anaerobic conditions with 0.32 mg P per mg synthesized PHB.Under anoxic conditions,strain YC accumulated 0.45 mg P per mg degraded PHB,which produced most of energy for phosphate accumulation (91.3%) and a little for glycogen synthesis (8.7%).This metabolic mechanism of strain YC is different from that of traditional phosphorus-accumulating organisms (PAOs).It is also found that PHB,a kind of intracellular polymer,plays a very important role in denitrifying and accumulating phosphorus by supplying sufficient energy for phosphorous accumulation and carbon sources for denitrification.Therefore,monitoring △P/△PHB and △NO2--N/△PHB is more necessary than monitoring △P/△COD,△NO2--N/△COD,or △P/△NO2--N.

  1. Selective Pressure of Temperature on Competition and Cross-Feeding within Denitrifying and Fermentative Microbial Communities.

    Hanke, Anna; Berg, Jasmine; Hargesheimer, Theresa; Tegetmeyer, Halina E; Sharp, Christine E; Strous, Marc

    2015-01-01

    In coastal marine sediments, denitrification and fermentation are important processes in the anaerobic decomposition of organic matter. Microbial communities performing these two processes were enriched from tidal marine sediments in replicated, long term chemostat incubations at 10 and 25°C. Whereas denitrification rates at 25°C were more or less stable over time, at 10°C denitrification activity was unstable and could only be sustained either by repeatedly increasing the amount of carbon substrates provided or by repeatedly decreasing the dilution rate. Metagenomic and transcriptomic sequencing was performed at different time points and provisional whole genome sequences (WGS) and gene activities of abundant populations were compared across incubations. These analyses suggested that a temperature of 10°C selected for populations related to Vibrionales/Photobacterium that contributed to both fermentation (via pyruvate/formate lyase) and nitrous oxide reduction. At 25°C, denitrifying populations affiliated with Rhodobacteraceae were more abundant. The latter performed complete denitrification, and may have used carbon substrates produced by fermentative populations (cross-feeding). Overall, our results suggest that a mixture of competition-for substrates between fermentative and denitrifying populations, and for electrons between both pathways active within a single population -, and cross feeding-between fermentative and denitrifying populations-controlled the overall rate of denitrification. Temperature was shown to have a strong selective effect, not only on the populations performing either process, but also on the nature of their ecological interactions. Future research will show whether these results can be extrapolated to the natural environment.

  2. Selective pressure of temperature on competition and cross-feeding within denitrifying and fermentative microbial communities

    Anna eHanke

    2016-01-01

    Full Text Available In coastal marine sediments, denitrification and fermentation are important processes in the anaerobic decomposition of organic matter. Microbial communities performing these two processes were enriched from tidal marine sediments in replicated, long term chemostat incubations at 10ºC and 25ºC. Whereas denitrification rates at 25ºC were more or less stable over time, at 10ºC denitrification activity was unstable and could only be sustained either by repeatedly increasing the amount of carbon substrates provided or by repeatedly decreasing the dilution rate. Metagenomic and transcriptomic sequencing was performed at different time points and provisional whole genome sequences and gene activities of abundant populations were compared across incubations. These analyses suggested that a temperature of 10ºC selected for populations related to Vibrionales/Photobacterium that contributed to both fermentation (via pyruvate/formate lyase and nitrous oxide reduction. At 25ºC, denitrifying populations affiliated with Rhodobacteracaea were more abundant. The latter performed complete denitrification, and may have used carbon substrates produced by fermentative populations (cross-feeding. Overall, our results suggest that a mixture of competition – for substrates between fermentative and denitrifying populations, and for electrons between both pathways active within a single population –, and cross feeding – between fermentative and denitrifying populations – controlled the overall rate of denitrification. Temperature was shown to have a strong selective effect, not only on the populations performing either process, but also on the nature of their ecological interactions. Future research will show whether these results can be extrapolated to the natural environment.

  3. Nitrifying and denitrifying bacteria in aerobic granules formed in sequencing batch airlift reactors

    WANG Fang; YANG Fenglin; QI Aijiu

    2007-01-01

    The purpose of this study was to investigate nitrifying bacteria and denitrifying bacteria isolated from aerobic granules.Aerobic granules were formed in an internal-circulate sequencing batch airlift reactor(SBAR)and biodegradation of NH3 -N was analyzed in the reactor.Bacteria were isolated and determined from aerobic granules using selected media.The growth properties and morphology of bacteria colonies were observed by controlling aerobic or anaerobic conditions in the culture medium.It was found that bacteria in aerobic granules were diverse and some of them were facultative aerobes.The diversity of bacteria in aerobic granules was a premise of simultaneous nitrification and denitrification.

  4. Quantification of anaerobic ammonium-oxidizing bacteria in enrichment cultures by quantitative competitive PCR

    HAO Chun; WANG Huan; LIU Qinhua; LI Xudong

    2009-01-01

    The anaerobic ammonium-oxidizing (ANAMMOX) bacteria were enriched from a sequencing batch biofilm reactor (SBBR) biofilm.We successfully developed a quantitative competitive polymerase chain reaction (QC-PCR) system to detect and quantify ANAMMOX bacteria in environmental samples.For QC-PCR system,PCR primer sets targeting 16S ribosomal RNA genes of ANAMMOX bacteria were designed and used.The quantification range of this system was 4 orders of magnitude,from 10~3 to 10~6 copies per PCR,corresponding to the detection limit of 300 target copies per mL.A 312-bp internal standard (IS) was constructed,which showed very similar amplification efficiency with the target amxC fragment (349 bp) over 4 orders of magnitude (10~3-10~6).The linear regressions were obtained with a R~2 of 0.9824 for 10~3 copies,R~2 of 0.9882 for 10~4 copies,0.9857 for 10~5 copies and 0.9899 for 10~6 copies.Using this method,we quantified ANAMMOX bacteria in a shortcut nitrification/denitrification-anammox system which is set for piggery wastewater treatment.

  5. Real-time PCR detection of Campylobacter spp.: A comparison to classic culturing and enrichment.

    de Boer, P; Rahaoui, H; Leer, R J; Montijn, R C; van der Vossen, J M B M

    2015-10-01

    The major disadvantage of the current gold standard for detection of the food pathogen Campylobacter, i.e. culturing, is the lengthy procedure. In this study we assessed the use of real-time PCR for detection of Campylobacter. To this end, 926 poultry samples, taken from transport containers and broiler caeca in The Netherlands in 2007, were subjected to three different real-time PCR detection methods: one targeting the Campylobacter jejuni hipO gene, one targeting the Campylobacter coli glyA gene, and one generically targeting Campylobacter spp. 16S rDNA sequence. The PCR results from the three different PCR protocols were compared to the work of Nauta et al. (2009) who analyzed the same set of samples collected from 62 broiler flocks by means of enrichment culturing. The results indicate that the generic 16S campylobacter PCR detection is equally reliable but much faster (4 h instead of ≥2 days) than detection by means of culturing. Moreover, PCR detection targeting the hipO and the glyA gene provide the possibility of C. jejuni and C. coli species discrimination. The generic Campylobacter spp. PCR analysis also confirmed the high incidence of Campylobacter spp. in poultry samples (∼90%) and the species specific PCR showed the simultaneous presence of C. jejuni and C. coli in ∼24% of the samples. Furthermore, the results from the three PCR analyses suggested the occurrence of alternative Campylobacter species in almost 10% of the samples. The campylobacter PCR detection methods reported here can replace traditional culturing because of being quicker and more reliable.

  6. A discourse on creating and rendering educational and cultural enrichment services to rural migrant workers by public libraries

    WANG; Zizhou; Charles; C.Yan

    2009-01-01

    As far as China’s enormous success in her economic reforms and development is concerned,Chinese rural migrant workers indeed have had their biggest share of contributions.Yet ironically in return,they have only received a disproportionate meager share of benefit rewards.These people represent a huge economically deprived group at the bottom of the social totem pole in China’s metropolises.On the whole as a social group,their educational attainment is relatively low as compared to their average urban coworkers.As such being the case,their rights to access some of the cost-free cultural and educational enrichment programs in the society are limited and not always assured.Nevertheless and in general speaking,they manifest a strong and consistent desire to acquire all sorts of new and practical knowledge by means of accessing the resources and facilities of their local public libraries.It is suggested in this paper that public libraries are in a good position to give strong support to the central government’s strategic planning for the development of a public culture service systema).In implementing such a government initiative with an unswerving purpose of advancing social justice and equality,public libraries should strife to provide as many as possible their library services at no cost to the public,especially to those socially deprived rural migrant workers.

  7. Implants composed of carbon fiber mesh and bone-marrow-derived, chondrocyte-enriched cultures for joint surface reconstruction.

    Robinson, D; Efrat, M; Mendes, D G; Halperin, N; Nevo, Z

    1993-01-01

    The current study integrates two distinct approaches in joint resurfacing into a combined type of implant, composed of carbon fiber mesh impregnated and coated with a hyaluronic-acid-based delivery substance containing cultured cells. Rabbit autogeneic chondrocyte-enriched cultures obtained from mesenchymal stem cells (chondroprogenitor cells) derived from adult rabbit bone marrow were grown in vitro under conditions favoring chondrogenesis. The improvement in quality of repair when a combined implant containing both cells and a carbon scaffold was used, in comparison to the utilization of carbon fiber mesh alone, was clearly demonstrated using clinical, histological, biochemical, and biomechanical examinations. Evaluations of the joints were performed at 6 weeks and 6 months after implantation. The repair tissue in the cell-implanted joints consisted of a typical hyaline cartilage, which was more cellular and thicker than the repair tissue in the hyaluronic-acid-impregnated carbon-fiber-implanted control joints. The hyaline cartilage in the experimental group formed a superficial layer above the carbon fibers, flush with the joint surface. In the controls, in which carbon fiber and the delivery substance alone were implanted, a histologically and biochemically fibrous tissue that was inferior biomechanically to the new cartilage was formed by the cells containing implants.

  8. Enhancement of Phenolics, Resveratrol and Antioxidant Activity by Nitrogen Enrichment in Cell Suspension Culture of Vitis vinifera

    Napaporn Sae-Lee

    2014-06-01

    Full Text Available Ammonium nitrate (NH4NO3, an important nitrogen source (34% N, has been used as an elicitor to stimulate plant growth and development as well as induce secondary metabolites under controlled conditions. In the present paper, we investigated the enhancement of cell biomass, total phenolics, resveratrol levels, and antioxidant activity of Vitis vinifera cv. Pok Dum by nitrogen enrichment (MS medium supplemented with NH4NO3 at 0, 500, 1,000, 5,000 and 10,000 mg/L. The highest accumulations of biomass, phenolics and resveratrol contents were observed at 8.8-fold (86.6 g DW/L, 15.9-fold (71.91 mg GAE/g DW and 5.6-fold (277.89 µg/g DW by the 14th day, in the medium supplemented with 500 mg/L NH4NO3. Moreover, the antioxidant activities of cultured grape cells estimated by the DPPH· and ABTS·+ assay were positively correlated with phenolics and resveratrol, and the maximum activity was also observed in cultured cells with 500 mg/L NH4NO3 at 176.11 and 267.79 mmol TE/100 g DW, respectively.

  9. Identification of enzymes involved in anaerobic benzene degradation by a strictly anaerobic iron-reducing enrichment culture.

    Abu Laban, Nidal; Selesi, Draženka; Rattei, Thomas; Tischler, Patrick; Meckenstock, Rainer U

    2010-10-01

    Anaerobic benzene degradation was studied with a highly enriched iron-reducing culture (BF) composed of mainly Peptococcaceae-related Gram-positive microorganisms. The proteomes of benzene-, phenol- and benzoate-grown cells of culture BF were compared by SDS-PAGE. A specific benzene-expressed protein band of 60 kDa, which could not be observed during growth on phenol or benzoate, was subjected to N-terminal sequence analysis. The first 31 amino acids revealed that the protein was encoded by ORF 138 in the shotgun sequenced metagenome of culture BF. ORF 138 showed 43% sequence identity to phenylphosphate carboxylase subunit PpcA of Aromatoleum aromaticum strain EbN1. A LC/ESI-MS/MS-based shotgun proteomic analysis revealed other specifically benzene-expressed proteins with encoding genes located adjacent to ORF 138 on the metagenome. The protein products of ORF 137, ORF 139 and ORF 140 showed sequence identities of 37% to phenylphosphate carboxylase PpcD of A. aromaticum strain EbN1, 56% to benzoate-CoA ligase (BamY) of Geobacter metallireducens and 67% to 3-octaprenyl-4-hydroxybenzoate carboxy-lyase (UbiD/UbiX) of A. aromaticum strain EbN1 respectively. These genes are proposed as constituents of a putative benzene degradation gene cluster (∼ 17 kb) composed of carboxylase-related genes. The identified gene sequences suggest that the initial activation reaction in anaerobic benzene degradation is probably a direct carboxylation of benzene to benzoate catalysed by putative anaerobic benzene carboxylase (Abc). The putative Abc probably consists of several subunits, two of which are encoded by ORFs 137 and 138, and belongs to a family of carboxylases including phenylphosphate carboxylase (Ppc) and 3-octaprenyl-4-hydroxybenzoate carboxy-lyase (UbiD/UbiX).

  10. Characterization of Fe (III)-reducing enrichment culture and isolation of Fe (III)-reducing bacterium Enterobacter sp. L6 from marine sediment.

    Liu, Hongyan; Wang, Hongyu

    2016-07-01

    To enrich the Fe (III)-reducing bacteria, sludge from marine sediment was inoculated into the medium using Fe (OH)3 as the sole electron acceptor. Efficiency of Fe (III) reduction and composition of Fe (III)-reducing enrichment culture were analyzed. The results indicated that the Fe (III)-reducing enrichment culture with the dominant bacteria relating to Clostridium and Enterobacter sp. had high Fe (III) reduction of (2.73 ± 0.13) mmol/L-Fe (II). A new Fe (III)-reducing bacterium was isolated from the Fe (III)-reducing enrichment culture and identified as Enterobacter sp. L6 by 16S rRNA gene sequence analysis. The Fe (III)-reducing ability of strain L6 under different culture conditions was investigated. The results indicated that strain L6 had high Fe (III)-reducing activity using glucose and pyruvate as carbon sources. Strain L6 could reduce Fe (III) at the range of NaCl concentrations tested and had the highest Fe (III) reduction of (4.63 ± 0.27) mmol/L Fe (II) at the NaCl concentration of 4 g/L. This strain L6 could reduce Fe (III) with unique properties in adaptability to salt variation, which indicated that it can be used as a model organism to study Fe (III)-reducing activity isolated from marine environment.

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

    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

  12. Establishment of microbial eukaryotic enrichment cultures from a chemically stratified antarctic lake and assessment of carbon fixation potential.

    Dolhi, Jenna M; Ketchum, Nicholas; Morgan-Kiss, Rachael M

    2012-04-20

    Lake Bonney is one of numerous permanently ice-covered lakes located in the McMurdo Dry Valleys, Antarctica. The perennial ice cover maintains a chemically stratified water column and unlike other inland bodies of water, largely prevents external input of carbon and nutrients from streams. Biota are exposed to numerous environmental stresses, including year-round severe nutrient deficiency, low temperatures, extreme shade, hypersalinity, and 24-hour darkness during the winter (1). These extreme environmental conditions limit the biota in Lake Bonney almost exclusively to microorganisms (2). Single-celled microbial eukaryotes (called "protists") are important players in global biogeochemical cycling (3) and play important ecological roles in the cycling of carbon in the dry valley lakes, occupying both primary and tertiary roles in the aquatic food web. In the dry valley aquatic food web, protists that fix inorganic carbon (autotrophy) are the major producers of organic carbon for organotrophic organisms (4, 2). Phagotrophic or heterotrophic protists capable of ingesting bacteria and smaller protists act as the top predators in the food web (5). Last, an unknown proportion of the protist population is capable of combined mixotrophic metabolism (6, 7). Mixotrophy in protists involves the ability to combine photosynthetic capability with phagotrophic ingestion of prey microorganisms. This form of mixotrophy differs from mixotrophic metabolism in bacterial species, which generally involves uptake dissolved carbon molecules. There are currently very few protist isolates from permanently ice-capped polar lakes, and studies of protist diversity and ecology in this extreme environment have been limited (8, 4, 9, 10, 5). A better understanding of protist metabolic versatility in the simple dry valley lake food web will aid in the development of models for the role of protists in the global carbon cycle. We employed an enrichment culture approach to isolate potentially

  13. Geochemical diversity in S processes mediated by culture-adapted and environmental-enrichments of Acidithiobacillus spp.

    Bernier, Luc; Warren, Lesley A.

    2007-12-01

    Coupled S speciation and acid generation resulting from S processing associated with five different microbial treatments, all primarily Acidithiobacillus spp. (i.e. autotrophic S-oxidizers) were evaluated in batch laboratory experiments. Microbial treatments included two culture-adapted strains, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, their consortia and two environmental enrichments from a mine tailings lake that were determined to be >95% Acidithiobacillus spp., by whole-cell fluorescent hybridization. Using batch experiments simulating acidic mine waters with no carbon amendments, acid generation, and S speciation associated with the oxidation of three S substrates (thiosulfate, tetrathionate, and elemental S) were evaluated. Aseptic controls showed no observable pH decrease over the experimental time course (1 month) for all three S compounds examined. In contrast, pH decreased in all microbial treatments from starting pH values of 4 to 2 or less for all three S substrates. Results show a non-linear relationship between the pH dynamics of the batch cultures and their corresponding sulfate concentrations, and indicate how known microbial S processing pathways have opposite impacts, ultimately on pH dynamics. Associated geochemical modeling indicated negligible abiogenic processes contributing to the observed results, indicating strong microbial control of acid generation extending over pH ranges from 4 to less than 2. However, the observed acid generation rates and associated S speciation were both microbial treatment and substrate-specific. Results reveal a number of novel insights regarding microbial catalysis of S oxidation: (1) metabolic diversity in S processing, as evidenced by the observed geochemical signatures in S chemical speciation and rates of acid generation amongst phylogenetically similar organisms (to the genus level); (2) consortial impacts differ from those of individual strain members; (3) environmental enrichments

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

    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.

  15. The metabolism of neonicotinoid insecticide thiamethoxam by soil enrichment cultures, and the bacterial diversity and plant growth-promoting properties of the cultured isolates.

    Zhou, Guang-Can; Wang, Ying; Ma, Yuan; Zhai, Shan; Zhou, Ling-Yan; Dai, Yi-Jun; Yuan, Sheng

    2014-01-01

    A soil enrichment culture (SEC) rapidly degraded 96% of 200 mg L(-1) neonicotinoid insecticide thiamethoxam (TMX) in MSM broth within 30 d; therefore, its metabolic pathway of TMX, bacterial diversity and plant growth-promoting rhizobacteria (PGPR) activities of the cultured isolates were studied. The SEC transformed TMX via the nitro reduction pathway to form nitrso, urea metabolites and via cleavage of the oxadiazine cycle to form a new metabolite, hydroxyl CLO-tri. In addition, 16S rRNA gene-denaturing gradient gel electrophoresis analysis revealed that uncultured rhizobacteria are predominant in the SEC broth and that 77.8% of the identified bacteria belonged to uncultured bacteria. A total of 31 cultured bacterial strains including six genera (Achromobacter, Agromyces, Ensifer, Mesorhizobium, Microbacterium and Pseudoxanthomonas) were isolated from the SEC broth. The 12 strains of Ensifer adhaerens have the ability to degrade TMX. All six selected bacteria showed PGPR activities. E. adhaerens TMX-23 and Agromyces mediolanus TMX-25 produced indole-3-acetic acid, whereas E. adhaerens TMX-23 and Mesorhizobium alhagi TMX-36 are N2-fixing bacteria. The six-isolated microbes were tolerant to 200 mg L(-1) TMX, and the growth of E. adhaerens was significantly enhanced by TMX, whereas that of Achromobacter sp. TMX-5 and Microbacterium sp.TMX-6 were enhanced slightly. The present study will help to explain the fate of TMX in the environment and its microbial degradation mechanism, as well as to facilitate future investigations of the mechanism through which TMX enhances plant vigor.

  16. Effect on the Growth of Denitrifying Bacteria from Different Carbon Sources%不同碳源对反硝化细菌生长的影响

    李建; 潘康成

    2012-01-01

    The growth of bacteria was relative to carbon sources intimately. The experiment was designed to find the best carbon source in enlarging denitrifying bacteria by research into effect on the growth of denitrifying bacteria from different carbon sources. The 5 carbon sources including glucose, potassium sodium tartrate, cane sugar, acetic acid and ethanol were used as the only carbon source respectively taking denitrifying bacteria into liquid culture media in the contrast test. Live bacteria number was used to denitrifying bacteria from different carbon sources. The results made it clear that of denitrifying bacteria more remarkably than the others. The results indicated others in enlarging denitrifying bacteria. estimate effect on the growth of glucose could promote the growth that glucose was better than the%细菌的生长速度和碳源有非常密切的关系,研究不同碳源对反硝化细菌生长的影响,以找到适合用于扩大培养菌种的最佳碳源。分别采用葡萄糖、酒石酸钾钠、蔗糖、乙酸和乙醇5种碳源作为唯一碳源,接种反硝化细菌进行对比实验,采用活菌数来反映不同碳源对反硝化细菌生长的影响。结果显示,葡萄糖促进反硝化细菌生长的作用明显优于其余4种碳源。对反硝化细菌进行扩大培养,葡萄糖的效果是比较好的。

  17. Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part B--Nitrogen-, Sulfur-, and Oxygen-Containing Heterocyclic Aromatic Compounds.

    Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

    2015-07-01

    Present study focused on the biodegradation of various heterocyclic nitrogen, sulfur, and oxygen (NSO) compounds using naphthalene-enriched culture. Target compounds in the study were pyridine, quinoline, benzothiophene, and benzofuran. Screening studies were carried out using different microbial consortia enriched with specific polycyclic aromatic hydrocarbon (PAH) and NSO compounds. Among different microbial consortia, naphthalene-enriched culture was the most efficient consortium based on high substrate degradation rate. Substrate degradation rate with naphthalene-enriched culture followed the order pyridine > quinoline > benzofuran > benzothiophene. Benzothiophene and benzofuran were found to be highly recalcitrant pollutants. Benzothiophene could not be biodegraded when concentration was above 50 mg/l. It was observed that 2-(1H)-quinolinone, benzothiophene-2-one, and benzofuran-2,3-dione were formed as metabolic intermediates during biodegradation of quinoline, benzothiophene, and benzofuran, respectively. Quinoline-N and pyridine-N were transformed into free ammonium ions during the biodegradation process. Biodegradation pathways for various NSO compounds are proposed. Monod inhibition model was able to simulate single substrate biodegradation kinetics satisfactorily. Benzothiophene and benzofuran biodegradation kinetics, in presence of acetone, was simulated using a generalized multi-substrate model.

  18. Detection of Mycoplasma ovipneumoniae and M. arginini in bighorn sheep using enrichment culture coupled with genus- and species-specific polymerase chain reaction.

    Weiser, Glen C; Drew, Mark L; Cassirer, E Frances; Ward, Alton C S

    2012-04-01

    Mycoplasma species are of interest as possible primary pathogens in the pneumonia complex of bighorn sheep (Ovis canadensis). Previous investigations have not commonly detected low frequencies of Mycoplasma spp. from free-ranging bighorn sheep, possibly due to the fastidious and slow growth of these organisms. We developed a culture protocol that employed an average initial 3-day enrichment culture in liquid Hayflick broth in a CO(2)-enhanced atmosphere. The broth was plated to solid Hayflick medium and the cultures observed for growth for up to 30 days. Polymerase chain reaction (PCR) was performed on DNA isolated from the enrichment broth and on isolates obtained from culture using Mycoplasma genus-specific PCR assays and species-specific PCR assays for M. arginini and M. ovipneumoniae. Some cultures that grew on Hayflick plates were picked as single colonies but were mixed because two organisms may grow together and appear as a single colony. Culture and PCR tests produced similar results for M. arginini, but for M. ovipneumoniae, culture alone was less accurate than PCR. Use of genus-specific primers also may allow detection of other species in samples negative for M. arginini and M. ovipneumoniae. Two methods of transport from field to laboratory (Port-a-Cul™ tubes, cryoprotectant in liquid N(2) and Fisher Transport System) gave similar results under our study conditions.

  19. Denitrifying bioreactors for nitrate removal from tile drained cropland

    Denitrification bioreactors are a promising technology for mitigation of nitrate-nitrogen (NO3-N) losses in subsurface drainage water. Bioreactors are constructed with carbon substrates, typically wood chips, to provide a substrate for denitrifying microorganisms. Researchers in Iowa found that for ...

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

    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...

  1. Study on separation and induction of high efficient denitrifier

    HUO Ai-qun; YU Tao; TAN Xin; ZHAO Lin

    2005-01-01

    A kind of denitrifier HY - 1 initially obtained from activated sludge was domesticated and inducted with UV and illumination to a new species bacterium HY -2 that has high bioactivity at low temperature. HY 2 was most active at 13 ℃. Nitrate and CODer removal efficiency was investigated under different temperature and C/N ratio.

  2. Denitrification and the denitrifier community in coastal microbial mats

    Fan, H.; Bolhuis, H.; Stal, L.J.

    2015-01-01

    Denitrification was measured in three structurally different coastal microbial mats by using the stable isotope technique. The composition of the denitrifying community was determined by analyzing the nitrite reductase (nirS and nirK) genes using clone libraries and the GeoChip. The highest potentia

  3. Comparison of polymerase chain reaction methods and plating for analysis of enriched cultures of Listeria monocytogenes when using the ISO11290-1 method.

    Dalmasso, Marion; Bolocan, Andrei Sorin; Hernandez, Marta; Kapetanakou, Anastasia E; Kuchta, Tomáš; Manios, Stavros G; Melero, Beatriz; Minarovičová, Jana; Muhterem, Meryem; Nicolau, Anca Ioana; Rovira, Jordi; Skandamis, Panagiotis N; Stessl, Beatrix; Wagner, Martin; Jordan, Kieran; Rodríguez-Lázaro, David

    2014-03-01

    Analysis for Listeria monocytogenes by ISO11290-1 is time-consuming, entailing two enrichment steps and subsequent plating on agar plates, taking five days without isolate confirmation. The aim of this study was to determine if a polymerase chain reaction (PCR) assay could be used for analysis of the first and second enrichment broths, saving four or two days, respectively. In a comprehensive approach involving six European laboratories, PCR and traditional plating of both enrichment broths from the ISO11290-1 method were compared for the detection of L. monocytogenes in 872 food, raw material and processing environment samples from 13 different dairy and meat food chains. After the first and second enrichments, total DNA was extracted from the enriched cultures and analysed for the presence of L. monocytogenes DNA by PCR. DNA extraction by chaotropic solid-phase extraction (spin column-based silica) combined with real-time PCR (RTi-PCR) was required as it was shown that crude DNA extraction applying sonication lysis and boiling followed by traditional gel-based PCR resulted in fewer positive results than plating. The RTi-PCR results were compared to plating, as defined by the ISO11290-1 method. For first and second enrichments, 90% of the samples gave the same results by RTi-PCR and plating, whatever the RTi-PCR method used. For the samples that gave different results, plating was significantly more accurate for detection of positive samples than RTi-PCR from the first enrichment, but RTi-PCR detected a greater number of positive samples than plating from the second enrichment, regardless of the RTi-PCR method used. RTi-PCR was more accurate for non-food contact surface and food contact surface samples than for food and raw material samples especially from the first enrichment, probably because of sample matrix interference. Even though RTi-PCR analysis of the first enrichment showed less positive results than plating, in outbreak scenarios where a rapid result is

  4. Trace Gas Emission from in-Situ Denitrifying Bioreactors

    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.

  5. Legal Thinking on the Construction of Culture -Enriched Beijing%"人文北京"建设的法制思考

    杨积堂

    2012-01-01

    The core of Culture - enriched Beijing construction lies in humanity and culture. From the perspec- tive of humanity, Culture - enriched Beijing construction aims to build up a more prosperous, civilized, harmoni- ous, livable and healthy socialist society. From the perspective of culture, Culture -enriched Beijing construction aims to build up the socialism with Chinese characteristics with the most humanistic concern, civilized and cultural charm capital. Legal construction is the significant aim and content requirement. For one thing, rule of law is one of content requirements to realize the real Culture - enriched Beijing. For another, perfecting the legal system is the fundamental guarantee in Culture -enriched Beijing construction. The perfect culture legal system, harmonious and efficient enforcement of cultural mechanism, uncorrupted judicial operation mechanism as well as convenient law intermediary service mechanism are the requirements of cultural legal construction. As for the legal system construc- tion, laying down the legal construction strategy, perfecting the local cultural code system and creating good legal atmosphere for Culture -enriched Beijing construction are proposed.%“人文北京”建设的核心是“人”和“文”,以人为本,以文化人,从“人”的角度,“人文北京”就是要建设更加繁荣、文明、和谐、宜居、健康的社会主义和谐社会“首善之区”。从“文”的角度.“人文北京”就是要建成最具人文关怀、最显文明风采、最有文化魅力的中国特色社会主义先进文化之都。“法治”建设,是人文北京建设的重要目标和内涵要求。一方面,法治是实现真正的“人文北京”的内涵之一;另一方面,健全法制又是“人文北京”建设的根本保障。完善的文化法律法规体系、协调高效的文化执法机制、廉洁公正的司法运行机制、便捷的法律中介服务机制是文化法制

  6. Nitrate removal, communities of denitrifiers and adverse effects in different carbon substrates for use in denitrification beds.

    Warneke, Sören; Schipper, Louis A; Matiasek, Michael G; Scow, Kate M; Cameron, Stewart; Bruesewitz, Denise A; McDonald, Ian R

    2011-11-01

    Denitrification beds are containers filled with wood by-products that serve as a carbon and energy source to denitrifiers, which reduce nitrate (NO(3)(-)) from point source discharges into non-reactive dinitrogen (N(2)) gas. This study investigates a range of alternative carbon sources and determines rates, mechanisms and factors controlling NO(3)(-) removal, denitrifying bacterial community, and the adverse effects of these substrates. Experimental barrels (0.2 m(3)) filled with either maize cobs, wheat straw, green waste, sawdust, pine woodchips or eucalyptus woodchips were incubated at 16.8 °C or 27.1 °C (outlet temperature), and received NO(3)(-) enriched water (14.38 mg N L(-1) and 17.15 mg N L(-1)). After 2.5 years of incubation measurements were made of NO(3)(-)-N removal rates, in vitro denitrification rates (DR), factors limiting denitrification (carbon and nitrate availability, dissolved oxygen, temperature, pH, and concentrations of NO(3)(-), nitrite and ammonia), copy number of nitrite reductase (nirS and nirK) and nitrous oxide reductase (nosZ) genes, and greenhouse gas production (dissolved nitrous oxide (N(2)O) and methane), and carbon (TOC) loss. Microbial denitrification was the main mechanism for NO(3)(-)-N removal. Nitrate-N removal rates ranged from 1.3 (pine woodchips) to 6.2 g N m(-3) d(-1) (maize cobs), and were predominantly limited by C availability and temperature (Q(10) = 1.2) when NO(3)(-)-N outlet concentrations remained above 1 mg L(-1). The NO(3)(-)-N removal rate did not depend directly on substrate type, but on the quantity of microbially available carbon, which differed between carbon sources. The abundance of denitrifying genes (nirS, nirK and nosZ) was similar in replicate barrels under cold incubation, but varied substantially under warm incubation, and between substrates. Warm incubation enhanced growth of nirS containing bacteria and bacteria that lacked the nosZ gene, potentially explaining the greater N(2)O emission in

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

    Gengping Ye

    Full Text Available 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 (P<0.05 concentrations of plasma glucose and total protein, ruminal volatile fatty acid and molar proportion of propionate, and significantly lower (P<0.05 ruminal pH and ammonia nitrogen. These parameters changed linearly with increasing GY supplementation level (P<0.05. In conclusion, GY has great potential to be developed as a feed additive with dual effects of glycerol and yeast for ruminants.

  8. Landfill Leachate as Enrichment Culture for Ammonia-Oxidizing Bacteria%利用垃圾渗滤液富集培养氨氧化菌

    崔荣; 李金玲; 李凤德; 韩京龙

    2011-01-01

    Maintaining a certain amount of active ammonia-oxidizing bacteria (AOB) in activated sludge is essential for the biological nitrogen removal process. The addition of enriched AOB into activated sludge is an effective option to increase AOB population. To economically get enriched AOB and effectively treat landfill leachate, the feasibility of using landfill leachate as a culture for enriching AOB was examined. Leachate from the Yantai municipal landfill site was used as the culture, and returned sludge from the Xin' an River municipal sewage treatment plant A2/O process was used as seed sludge. The AOB were enriched by fed batch cultivation. The results showed that after four cultivation cycles, the population of cells in the enriched AOB was 5. 6 times higher than the original activated sludge. By adding 14.5% of enriched AOB after four cultivation cycles into the activated sludge, the ammonia oxidation rate increased by 65.4%, which confirmed that landfill leachate could be used as a culture for enriching AOB.%确保活性污泥中适当的氨氧化菌(AOB)的数量及活性对污水生物除氮过程至关重要,投加富集AOB是增加活性污泥中AOB浓度的方法之一.为了经济有效地获取富集的AOB并有效处理难降解的垃圾渗滤液,对利用垃圾渗滤液富集培养AOB的可行性进行了研究.采用烟台市生活垃圾填埋场的垃圾渗滤液作为培养基,利用辛安河污水处理厂A2/O工艺二沉池的回流污泥进行接种,通过更代方式富集培养AOB.结果显示:更代4次后,菌液中AOB的浓度增至原来的5.6倍;向活性污泥中投加14.5%的经过4次更代富集培养的AOB,氨氧化速率提高了65.4%,从而验证了利用垃圾渗滤液富集AOB是可行的.

  9. Development of PCR primer systems for amplification of nitrite reductase genes (nirK and nirS) to detect denitrifying bacteria in environmental samples

    Braker, G.; Witzel, K.P. [Max-Planck-Inst. fuer Limnologie, Ploen (Germany); Fesefeldt, A. [Univ. Kiel (Germany). Inst. fuer Allgemeine Mikrobiologie

    1998-10-01

    A system was developed for the detection of denitrifying bacteria by the application of specific nitrite reductase gene fragments with PCR. Primer sequences were found for the amplification of fragments from both nitrite reductase genes (nirK and nirS) after comparative sequence analysis. Whenever amplification was tried with these primers, the known nir type of denitrifying laboratory cultures could be confirmed. Likewise, the method allowed a determination of the nir type of five laboratory strains. The nirK gene could be amplified from Blastobacter denitrificans, Alcaligenes xylosoxidans, and Alcaligenes sp. (DSM 30128); the nirS gene was amplified from Alcaligenes eutrophus DSM 530 and from the denitrifying isolate IFAM 3698. For each of the two genes, at least one primer combination amplified successfully for all of the test strains. Specific amplification products were not obtained wit h nondenitrifying bacteria or with strains of the other nir type. The specificity of the amplified products was confirmed by subsequent sequencing. These results suggest the suitability of the method for the qualitative detection of denitrifying bacteria in environmental samples. This was shown by applying the generally amplifying primer combination for each nir gene developed in this study to total DNA preparations from aquatic habitats.

  10. High frequency of Thermodesulfovibrio spp. and Anaerolineaceae in association with Methanoculleus spp. in a long-term incubation of n-alkanes-degrading methanogenic enrichment culture

    Bo Liang

    2016-09-01

    Full Text Available In the present study, the microbial community and functional gene composition of a long-term active alkane-degrading methanogenic culture was established after two successive enrichment culture transfers and incubated for a total period of 1750 days. Molecular analysis was conducted after the second transfer (incubated for 750 days for both the active alkanes-degrading methanogenic enrichment cultures (T2-AE and the background control (T2-BC. A net increase of methane as the end product was detected in the headspace of the enrichment cultures amended with long-chain n-alkanes and intermediate metabolites, including octadecanoate, hexadecanoate, isocaprylate, butyrate, isobutyrate, propionate, acetate and formate were measured in the liquid cultures. The composition of microbial community shifted through the successive transfers over time of incubation. Sequences of bacterial and archaeal 16S rRNA gene (16S rDNA and mcrA functional gene indicated that bacterial sequences affiliated to Thermodesulfovibrio spp. and Anaerolineaceae and archaeal sequences falling within the genus Methanoculleus were the most frequently encountered and thus represented the dominant members performing the anaerobic degradation of long-chain n-alkanes and methanogenesis. In addition, the presence of assA functional genes encoding the alkylsuccinate synthase α subunit indicated that fumarate addition mechanism could be considered as a possible initial activation step of n-alkanes in the present study. The succession pattern of microbial communities indicates that Thermodesulfovibrio spp. could be a generalist participating in the metabolism of intermediates, while Anaerolineaceae plays a key role in the initial activation of long-chain n-alkane biodegradation.

  11. 海洋细菌增菌培养方法的研究%Cultural methods of enrichment in ocean bacteria

    马聪; 蒋学兵; 刘敏; 张在文; 王海东; 陈昌国; 郭建巍

    2008-01-01

    Objective To explore the effecitve cultural methods of enrichment in ocean bacteria. Methods Different kinds of cultural mediums were selectd to culture seawater bacteria. Results Both alkaline peptone water( APW) and halophilic bacteria liquid had good effects to Vibrio enrichment. NO. 2 nutrient broth was effective for ordinary bacteria. Eumycete could be isolated from seawater by cultural sabouraud liquid. Conclusions APW and halophilic bacteria liquid should be selected for Vibrio enrichment, NO. 2 nutrient broth for ordinary bacteria. Moreover, cultural sabouraud liquid can be effective for fungus.%目的 探讨理想的海洋细菌增菌培养方法.方法 选择不同种类的增菌培养液对海水中细菌进行增菌培养.结果 碱性蛋白胨水与嗜盐菌增菌液对海水弧菌具有良好的增菌效果,2号营养肉汤适合海水普通细菌的增菌培养,液体沙保氏增菌液能从海水中增菌培养出真菌.结论 海水中弧菌增菌应选用碱性蛋白胨水与嗜盐菌增菌液,增菌普通细菌应选用2号营养肉汤,真菌应选用液体沙保氏增菌液.

  12. Composting-Like Conditions Are More Efficient for Enrichment and Diversity of Organisms Containing Cellulase-Encoding Genes than Submerged Cultures.

    Heiss-Blanquet, Senta; Fayolle-Guichard, Françoise; Lombard, Vincent; Hébert, Agnès; Coutinho, Pedro M; Groppi, Alexis; Barre, Aurélien; Henrissat, Bernard

    2016-01-01

    Cost-effective biofuel production from lignocellulosic biomass depends on efficient degradation of the plant cell wall. One of the major obstacles for the development of a cost-efficient process is the lack of resistance of currently used fungal enzymes to harsh conditions such as high temperature. Adapted, thermophilic microbial communities provide a huge reservoir of potentially interesting lignocellulose-degrading enzymes for improvement of the cellulose hydrolysis step. In order to identify such enzymes, a leaf and wood chip compost was enriched on a mixture of thermo-chemically pretreated wheat straw, poplar and Miscanthus under thermophile conditions, but in two different set-ups. Unexpectedly, metagenome sequencing revealed that incubation of the lignocellulosic substrate with compost as inoculum in a suspension culture resulted in an impoverishment of putative cellulase- and hemicellulase-encoding genes. However, mimicking composting conditions without liquid phase yielded a high number and diversity of glycoside hydrolase genes and an enrichment of genes encoding cellulose binding domains. These identified genes were most closely related to species from Actinobacteria, which seem to constitute important players of lignocellulose degradation under the applied conditions. The study highlights that subtle changes in an enrichment set-up can have an important impact on composition and functions of the microcosm. Composting-like conditions were found to be the most successful method for enrichment in species with high biomass degrading capacity.

  13. Diversity of Denitrifying Bacteria in the San Francisco Bay

    Atluri, A.; Lee, J.; Francis, C. A.

    2012-12-01

    We compared the diversity of communities of denitrifying bacteria from the San Francisco Bay to investigate whether environmental factors affect diversity. To do this, we studied the sequence diversity of the marker gene nirK. nirK codes for the enzyme nitrite reductase which helps reduce nitrite to nitric oxide, an important step in denitrification. Sediment samples were collected spatially from five different locations and temporally during the four different seasons along a salinity gradient in the bay. After collecting samples and extracting DNA from them, we used PCR to amplify our gene of interest, created clone libraries for sequencing, and compared phylogenetic trees from the different communities. Based on several phylogenetic analyses on our tree and environments, we saw that denitrifying bacteria from the North and Central Bay form distinct spatial clusters; Central Bay communities are very similar to each other, while communities from the North Bay are more distinct from each other and from communities in the Central Bay. Bacteria from site 8.1M (Carquinez Strait) showed the most cm-scale spatial diversity, and there was the most species richness during the winter. All this suggests that diversity of communities of denitrifying bacteria may be affected by spatial and temporal environmental factors.

  14. Denitrification characteristics of a marine origin psychrophilic aerobic denitrifying bacterium

    Haiyan Zheng; Ying Liu; Guangdong Sun; Xiyan Gao; Qingling Zhang; Zhipei Liu

    2011-01-01

    A psychrophilic aerobic denitrifying bacterium,strain S1-1,was isolated from a biological aerated filter conducted for treatment of recirculating water in a marine aquaculture system.Strain S1-1 was preliminarily identified as Psychrobacter sp.based on the analysis of its 16S rRNA gene sequence,which showed 100% sequence similarity to that of Psychrobacter sp.TSBY-70.Strain S 1-1 grew well either in high nitrate or high nitrite conditions with a removal of 100% nitrate or 63.50% nitrite,and the total nitrogen removal rates could reach to 46.48% and 31.89%,respectively.The results indicated that nitrate was mainly reduced in its logarithmic growth phase with a very low leve 1 accumulation of nitrite,suggesting that the aerobic denitrification process of strain S l-1 occurred mainly in this phase.The GC-MS results showed that N2O was formed as the major intermediate during the aerobic denitrifying process of strain S1-1.Finally,factors affecting the growth of strain Sl-1 and its aerobic denitrifying ability were also investigated.Results showed that the optimum aerobic denitrification conditions for strain S1-1 were sodium succinate as carbon source,C/N ratio15,salinity 10 g/L NaCl,incubation temperature 20℃ and initial pH 6.5.

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

    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.

  16. Multiplexed Single Intact Cell Droplet Digital PCR (MuSIC ddPCR) Method for Specific Detection of Enterohemorrhagic E. coli (EHEC) in Food Enrichment Cultures

    McMahon, Tanis C.; Blais, Burton W.; Wong, Alex; Carrillo, Catherine D.

    2017-01-01

    Foodborne illness attributed to enterohemorrhagic E. coli (EHEC), a highly pathogenic subset of Shiga toxin-producing E. coli (STEC), is increasingly recognized as a significant public health issue. Current microbiological methods for identification of EHEC in foods often use PCR-based approaches to screen enrichment broth cultures for characteristic gene markers [i.e., Shiga toxin (stx) and intimin (eae)]. However, false positives arise when complex food matrices, such as beef, contain mixtures of eae-negative STEC and eae-positive E. coli, but no EHEC with both markers in a single cell. To reduce false-positive detection of EHEC in food enrichment samples, a Multiplexed, Single Intact Cell droplet digital PCR (MuSIC ddPCR) assay capable of detecting the co-occurrence of the stx and eae genes in a single bacterial cell was developed. This method requires: (1) dispersal of intact bacteria into droplets; (2) release of genomic DNA (gDNA) by heat lysis; and (3) amplification and detection of genetic targets (stx and eae) using standard TaqMan chemistries with ddPCR. Performance of the method was tested with panels of EHEC and non-target E. coli. By determining the linkage (i.e., the proportion of droplets in which stx and eae targets were both amplified), samples containing EHEC (typically greater than 20% linkage) could be distinguished from samples containing mixtures of eae-negative STEC and eae-positive E. coli (0–2% linkage). The use of intact cells was necessary as this linkage was not observed with gDNA extracts. EHEC could be accurately identified in enrichment broth cultures containing excess amounts of background E. coli and in enrichment cultures derived from ground beef/pork and leafy-green produce samples. To our knowledge, this is the first report of dual-target detection in single bacterial cells using ddPCR. The application of MuSIC ddPCR to enrichment-culture screening would reduce false-positives, thereby improving the cost, speed, and accuracy of

  17. Enrichment of prostate cancer stem-like cells from human prostate cancer cell lines by culture in serum-free medium and chemoradiotherapy.

    Wang, Lei; Huang, Xing; Zheng, Xinmin; Wang, Xinghuan; Li, Shiwen; Zhang, Lin; Yang, Zhonghua; Xia, Zhiping

    2013-01-01

    The discovery of rare subpopulations of cancer stem cells (CSCs) has created a new focus in cancer research. As CSCs demonstrate resistance to chemoradiation therapy relative to other cancer cells, this allows the enrichment of CSC populations by killing apoptosis-susceptible cancer cells. In this study, three commonly used human prostate cancer (PCa) cell lines (DU145, PC-3 and LNCaP) were examined for their expression of the putative stem cell markers CD133 and CD44 via flow cytometric analysis. Under normal culture conditions, CD133(+)/CD44(+) cells were only present in the DU145 cell line, and comprised only a minor percentage (0.1% ± 0.01%) of the total population. However, the proportion of these CD133(+)/CD44(+) prostate CSCs could be increased in these cell lines via culture in serum-free medium (SFM), or through chemotherapy or radiotherapy. Indeed, after culture in SFM, the proportion of CD133(+)/CD44(+) cells in DU145 and PC-3 had increased to 10.3% and 3.0%, respectively. Moreover, the proportion had increased to 9.8% enriched by chemotherapy and 3.5% by radiotherapy in DU145. Colony-formation tests, cell invasion assays, and tumor xenografts in BALB/c nude mice were used to evaluate the stem cell properties of CD133(+)/CD44(+) PCa cells that were isolated via fluorescence-activated cell sorting (FACS). CD133(+)/CD44(+) cells had an enhanced colony-formation capability and invasive ability in vitro, and displayed greater tumorigenic properties in vivo. These results demonstrate the presence of CD133(+)/CD44(+) prostate CSCs in established PCa cell lines and that populations of these cells can be enriched by culture in SFM or chemoradiotherapy. Finding novel therapies to override chemoradiation resistance in the prostate CSCs is the key to improve long-term results in PCa management.

  18. Phylogenetic and Metabolic Diversity of Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-transforming Bacteria in Strictly Anaerobic Mixed Cultures Enriched on RDX as Nitrogen Source

    2003-01-01

    the Enterobacteriaceae family ( Klebsiella pneumoniae, Serratia marcescens, Morganella morganii, Citrobacter freundii, and Escherichia coli) [10,11... wastewater to methane (70% of the total gas released). The following compounds were added to the basic salts and vitamins medium to enrich bacteria using RDX...RDX biodegradation by a methanogenic enrichment culture obtained from an explosives man- ufacturing wastewater treatment plant. Technical report, pp. 99

  19. 富铬蚁巢伞(鸡(土从)菌)液体培养%Submerged culture of chromium-enriched Termitomyces albuminosus

    胡忠策; 郑晓冬; 陈新爱; 郑裕国

    2008-01-01

    A species of mushroom, Termitomyces albuminosus, was cultured in liquid medium for production of chromium-enriched mycelium. The influence of chromium (Ⅲ) on mycelial growth of T. albuminosus was investigated. An optimum medium composed of 5.6g/L yeast extract, 51.6g/L hydrolyzed rice, 2g/L KH2PO4,and 20mg/L chromium(Ⅲ) with initial pH of 4.5 was obtained by using method of central composite design (CCD). After incubation of 84h, the maximal biomass of chromium-enriched mycelia reached 24.23g DMW(dried mycelial weight)/L with 272μg/g DMW chromium content in 500mL flasks containing 100mL medium with an inoculum of 8% on a shaker of 100r/min under an optimized cultivation condition at 28℃.

  20. [Denitrifying and phosphorus accumulating mechanisms of denitrifying phosphorus accumulating organisms (DPAOs) for wastewater treatment--a review].

    Yu, Hongting; Li, Min

    2015-03-04

    Eutrophication has raised increasing concerns due to its adverse effects on creatures. It is widely accepted that microbes are capable of removing nitrogen (N) and phosphate (P) via denitrification and P accumulation. So far, several strains can do this work. Therefore, more studies are focused on looking for micro-organisms that have both denitrification and P accumulation ability. Whether exposed to aerobic or anaerobic environment, microbial N and P removal mechanisms differ. Proton Motive Force and Electron Acceptor Theory are involved in the chemical process, whereas denitrifying enzymes polyphosphate kinases are regarded as the leading participators in the enzymatic systems. Studies have shown the influences of N on P accumulation, but further investigation should identify the influences of P on N removal. Here we reviewed the aspects of N and P removal mechanisms in denitrifying phosphorus accumulating organisms (DPAOs) and their potential to remove N and P from water system. Moreover, future works on clarifying denitrifying phosphorus accumulating mechanisms in depth and improving efficiency of removing N and P by DPAOs are provided.

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

    Jensen, Annette Nygaard; Sørensen, Gitte; Baggesen, Dorte Lau

    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-enr...

  2. Biosynthesis of highly enriched 13C-lycopene for human metabolic studies using repeated batch tomato cell culturing with 13C-glucose.

    Moran, Nancy Engelmann; Rogers, Randy B; Lu, Chi-Hua; Conlon, Lauren E; Lila, Mary Ann; Clinton, Steven K; Erdman, John W

    2013-08-15

    While putative disease-preventing lycopene metabolites are found in both tomato (Solanum lycopersicum) products and in their consumers, mammalian lycopene metabolism is poorly understood. Advances in tomato cell culturing techniques offer an economical tool for generation of highly-enriched (13)C-lycopene for human bioavailability and metabolism studies. To enhance the (13)C-enrichment and yields of labelled lycopene from the hp-1 tomato cell line, cultures were first grown in (13)C-glucose media for three serial batches and produced increasing proportions of uniformly labelled lycopene (14.3±1.2%, 39.6±0.5%, and 48.9±1.5%) with consistent yields (from 5.8 to 9 mg/L). An optimised 9-day-long (13)C-loading and 18-day-long labelling strategy developed based on glucose utilisation and lycopene yields, yielded (13)C-lycopene with 93% (13)C isotopic purity, and 55% of isotopomers were uniformly labelled. Furthermore, an optimised acetone and hexane extraction led to a fourfold increase in lycopene recovery from cultures compared to a standard extraction.

  3. Epidemiology of Salmonella sp. in California cull dairy cattle: prevalence of fecal shedding and diagnostic accuracy of pooled enriched broth culture of fecal samples

    Omran A. Abu Aboud

    2016-08-01

    Full Text Available Background The primary objective of this cross-sectional study was to estimate the crude, seasonal and cull-reason stratified prevalence of Salmonella fecal shedding in cull dairy cattle on seven California dairies. A secondary objective was to estimate and compare the relative sensitivity (Se and specificity (Sp for pools of 5 and 10 enriched broth cultures of fecal samples for Salmonella sp. detection. Methods Seven dairy farms located in the San Joaquin Valley of California were identified and enrolled in the study as a convenience sample. Cull cows were identified for fecal sampling once during each season between 2014 and 2015, specifically during spring, summer, fall, and winter, and 10 cows were randomly selected for fecal sampling at the day of their sale. In addition, study personnel completed a survey based on responses of the herd manager to questions related to the previous four month’s herd management. Fecal samples were frozen until testing for Salmonella. After overnight enrichment in liquid broth, pools of enrichment broth (EBP were created for 5 and 10 samples. All individual and pooled broths were cultured on selective media with putative Salmonella colonies confirmed by biochemical testing before being serogrouped and serotyped. Results A total of 249 cull cows were enrolled into the study and their fecal samples tested for Salmonella. The survey-weighted period prevalence of fecal shedding of all Salmonella sp. in the cull cow samples across all study herds and the entire study period was 3.42% (N = 249; SE 1.07. The within herd prevalence of Salmonella shed in feces did not differ over the four study seasons (P = 0.074. The Se of culture of EBP of five samples was 62.5% (SE = 17.12, which was not statistically different from the Se of culture of EBP of 10 (37.5%, SE = 17.12, P = 0.48. The Sp of culture of EBP of five samples was 95.24% (SE = 3.29 and for pools of 10 samples was 100.00% (SE = 0. There was no statistical

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

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

    2008-01-01

    skeletal muscle repair mainly relies on the satellitecell, several reports have shown that vessel-associated cells may adopt a myogenic phenotype when exposed to a muscle environment. In accordance with these findings, we also observed invitro myogenic specification of SPCD45(-) cells when cocultured...... with myoblasts. Furthermore, immediate intramuscular engraftment of non-cultured SPCD45(-) cells gave rise to myofibres andcells lining blood vessels, whereas the SVF only provided donor derived mononuclear cells. We therefore conclude that the SPCD45(-) fraction of adipose-derived SVF is enriched for cells...

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

    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.

  6. Non-Neuronal Cells Are Required to Mediate the Effects of Neuroinflammation: Results from a Neuron-Enriched Culture System.

    Chin Wai Hui

    Full Text Available Chronic inflammation is associated with activated microglia and reactive astrocytes and plays an important role in the pathogenesis of neurodegenerative diseases such as Alzheimer's. Both in vivo and in vitro studies have demonstrated that inflammatory cytokine responses to immune challenges contribute to neuronal death during neurodegeneration. In order to investigate the role of glial cells in this phenomenon, we developed a modified method to remove the non-neuronal cells in primary cultures of E16.5 mouse cortex. We modified previously reported methods as we found that a brief treatment with the thymidine analog, 5-fluorodeoxyuridine (FdU, is sufficient to substantially deplete dividing non-neuronal cells in primary cultures. Cell cycle and glial markers confirm the loss of ~99% of all microglia, astrocytes and oligodendrocyte precursor cells (OPCs. More importantly, under this milder treatment, the neurons suffered neither cell loss nor any morphological defects up to 2.5 weeks later; both pre- and post-synaptic markers were retained. Further, neurons in FdU-treated cultures remained responsive to excitotoxicity induced by glutamate application. The immunobiology of the FdU culture, however, was significantly changed. Compared with mixed culture, the protein levels of NFκB p65 and the gene expression of several cytokine receptors were altered. Individual cytokines or conditioned medium from β-amyloid-stimulated THP-1 cells that were, potent neurotoxins in normal, mixed cultures, were virtually inactive in the absence of glial cells. The results highlight the importance of our glial-depleted culture system and identifies and offer unexpected insights into the complexity of -brain neuroinflammation.

  7. Simultaneous denitrifying phosphorus accumulation in a sequencing batch reactor

    YUAN Linjiang; HAN Wei; WANG Lei; YANG Yongzhe; WANG Zhiying

    2007-01-01

    In order to achieve simultaneous nitrogen and phosphorus removal in the biological treatment process,denitrifying phosphorus accumulation(DNPA)and its affecting factors were studied in a sequencing batch reactor(SBR)with synthetic wastewater.The results showed that when acetate was used as the sole carbon resource in the influent.the sludge acclimatized under anaerobic/aerobic operation had good phosphorus removal ability.Denitrifying phosphorus accumulation was observed soon when fed with nitrate instead of aeration following the anaerobic stage,which is a vital premise to DNPA.If DNPA sludge is fed with nitrate prior to the anaerobic stage,the DNPA would weaken or even disappear.At the high concen tration of nitrate fed in the anoxic stage,the longer anoxic time needed,the better the DNPA was.Induced DNPA did not disappear even though an aerobic stage followed the anoxic stage,but the shorter the aerobic stage lasted,the higher the proportions of phosphorus removal via DNPA to total removal.

  8. Dynamic Metabolic Modeling of Denitrifying Bacterial Growth: The Cybernetic Approach

    Song, Hyun-Seob; Liu, Chongxuan

    2015-06-29

    Denitrification is a multistage reduction process converting nitrate ultimately to nitrogen gas, carried out mostly by facultative bacteria. Modeling of the denitrification process is challenging due to the complex metabolic regulation that modulates sequential formation and consumption of a series of nitrogen oxide intermediates, which serve as the final electron acceptors for denitrifying bacteria. In this work, we examined the effectiveness and accuracy of the cybernetic modeling framework in simulating the growth dynamics of denitrifying bacteria in comparison with kinetic models. In four different case studies using the literature data, we successfully simulated diauxic and triauxic growth patterns observed in anoxic and aerobic conditions, only by tuning two or three parameters. In order to understand the regulatory structure of the cybernetic model, we systematically analyzed the effect of cybernetic control variables on simulation accuracy. The results showed that the consideration of both enzyme synthesis and activity control through u- and v-variables is necessary and relevant and that uvariables are of greater importance in comparison to v-variables. In contrast, simple kinetic models were unable to accurately capture dynamic metabolic shifts across alternative electron acceptors, unless an inhibition term was additionally incorporated. Therefore, the denitrification process represents a reasonable example highlighting the criticality of considering dynamic regulation for successful metabolic modeling.

  9. 异养硝化/好氧反硝化菌的分离鉴定及其在不同培养条件下产N_2O研究%Isolation of Heterotrophic Nitrifiers/Aerobic Denitrifiers and Their Roles in N_2O Production for Different Incubations

    蒋静艳; 胡正华; 黄耀

    2009-01-01

    Soil microorganisms are important sources of N_2O for the atmosphere. Peak emissions of N_2O are often observed after wetting of soil. The simultaneous heterotrophic: nitrifying and aerobic denitrifying hacteria with respect to N_2O emission were studied to obtain more information about the microbiological aspects of peak emissions. Using acelamide as the C and N source, two strains of nitrifying and denitrifying bacteria were isolated,coded as XM1 and HX2,respectively. XMlstrain was Gram-negative chain-like bacilli,and the HX2 was Gram-negative cocci. In enrichment culture,N_2O production of HX2 was 76 times more than XM1 . Two strains could grow with glucose,mannitol or sodium tartrate as sole carbon source,respectively. They could nitrify with sodium nitrate or denitrify with ammonium sulfate as unique nitrogen source, and produce intermediate product nitrite. XMlstrain growth velocity and nitrite formation were obviously higher than HX2. The phylogentic analysis based on partial 16S rDNA showed that two isolated strains were the closest relative of Pseudomonas sp.99% sequence similarity. Under different WFPS (water-filled-pore-space) conditions, the aerobic autoclaved soil incubation trial showed that, HX2 strain was suitable for growing in 30% WFPS,and N_2O production was (36.01 ± 2.48) ng/g which was 1.9 times than that in 60% WFPS. But XM1 was suitable for growing in 60% WFPS and almost had no N_2O production. To investigate the nitrifying and denitrifying mechanisms of heterotrophic nitrifiers/aerobic denitrifiers should be useful for mastering the mitigation way of soil N_2O emission in future.%以乙酰胺为唯一碳氮源分离纯化出2株既能异养硝化又能好氧反硝化的菌株XM1和HX2,革兰氏阴性,分别为链状杆菌和球状菌.在富集培养基中,菌株HX2产N_2O量为XM1的76倍;两菌株均能分别以葡萄糖、甘露醇、酒石酸钠为唯一碳源进行生长;也可分别以硝酸钠和硫酸铵为唯一氮源进行硝化

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

    Zafiriadis, I.; Kapagiannidis, A. G.; Aivasidis, A.

    2009-07-01

    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)

  11. Comparative analysis of tertiary alcohol esterase activity in bacterial strains isolated from enrichment cultures and from screening strain libraries.

    Herter, Susanne; Nguyen, Giang-Son; Thompson, Mark L; Steffen-Munsberg, Fabian; Schauer, Frieder; Bornscheuer, Uwe T; Kourist, Robert

    2011-05-01

    The preparation of enantiopure tertiary alcohols is of great contemporary interest due to the application of these versatile building blocks in organic synthesis and as precursors towards high value pharmaceutical compounds. Herein, we describe two approaches taken towards the discovery of novel biocatalysts for the synthesis of these valuable compounds. The first approach was initiated with screening of 47 bacterial strains for hydrolytic activity towards the simple tertiary alcohol ester tert-butyl acetate. In conjunction, a second method focussed on the isolation of strains competent for growth on tert-butyl acetate as the sole source of carbon and energy. From functional screening, 10 Gram-positive Actinomycetes showed hydrolytic activity, whilst enrichment selection resulted in the identification of 14 active strains, of which five belong to the Gram-negative cell-wall type. Bacterial strains obtained from both approaches were viable for enantioselective hydrolysis of pyridine substituted tertiary alcohol esters in addition to bulky aliphatic and keto-derived substrates from the same class. Activity towards each of the test substrates was uncovered, with promising enantioselectivities of up to E = 71 in the hydrolysis of a para-substituted pyridine tertiary alcohol ester using a strain of Rhodococcus ruber. Interestingly strains of Microbacterium and Alcaligenes sp. gave opposite enantiopreference in the hydrolysis of a meta-substituted pyridine tertiary alcohol ester with E values of 17 and 54. These approaches show that via both possibilities, screening established strain collections and performing enrichment selection, it is possible to identify novel species which show activity towards sterically challenging substrates.

  12. ENRICHMENT AND CHARACTERIZATION OF THYMUS-REPOPULATING CELLS IN STROMA-DEPENDENT CULTURES OF RAT BONE-MARROW

    PRAKAPAS, Z; DENOYELLE, M; DARGEMONT, C; KROESE, FGM; THIERY, JP; DEUGNIER, MA

    1993-01-01

    The bone marrow precursor cells seeding the thymus have been difficult to investigate using fresh bone marrow and in vivo thymus reconstitution assays. We have therefore designed a short-term bone marrow culture system allowing the study of thymus-repopulating cells in the marrow microenvironment. L

  13. An enrichment and acclimation procedure to obtain photo heterotrophic cultures for H{sub 2} production from organic effluents

    Acevedo-Benitez, J. A.; Ponce-Noyola, M. T.; Poggi-Varaldo, H. M.

    2009-07-01

    Production of H{sub 2} via photo heterotrophic is an attractive alternative, due to the capacity of photo heterotrophic organisms to convert the organic matter of effluents into H{sub 2}. The objective of our work was to develop a protocol for selecting undefined mixed cultures of photo heterotrophic microorganism with the capability of producing of H{sub 2}. (Author)

  14. Bringing the Past to the Present. : The use of tagging and storytelling for the enrichment of cultural heritage.

    Vliet, H.M.M. (Harry) van; Hekman, Erik

    2011-01-01

    The Internet’s dominant role in recent years has caused a change in the relationship between media producers, suppliers and consumers in the traditional media landscape. The cultural sector must therefore decide what to do with today’s digital media in response to the general public’s changing role,

  15. Greenhouse Gas Emission from In-situ Denitrifying Bioreactors

    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

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

    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.

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

    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.

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

    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.

  19. BIODEGRADATION OF AROMATIC COMPOUNDS UNDER MIXED OXYGEN/DENITRIFYING CONDITIONS: A REVIEW

    Bioremediation of aromatic hydrocarbons in groundwater and sediments is often limited by dissolved oxygen. Many aromatic hydrocarbons degrade very slowly or not at all under anaerobic conditions. Nitrate is a good alternative electron acceptor to oxygen, and denitrifying bacteria...

  20. Elimination of pharmaceuticals in single- and three-stage pre-denitrifying MBBR

    Polesel, Fabio; Torresi, Elena; Loreggian, L.;

    This study investigated the elimination of pharmaceuticals in pre-denitrifying moving bed biofilm reactors (MBBRs) in single- and three-stage configurations. Under batch conditions, biotransformation and retransformation of two pharmaceuticals (trimethoprim, sulfamethoxazole) occurred at comparable...

  1. Interactions between nitrifying and denitrifying bacteria in gnotobiotic microcosms planted with the emergent macrophyte Glyceria maxima

    Bodelier, P.L.E.; Duyts, H.; Blom, C.W.P.M.; Laanbroek, H.J.

    1998-01-01

    The population dynamics of the chemolithoautotrophic nitrifiers Nitrosomonas europaea and Nitrobacter winogradskyi were studied in gnotobiotic microcosms fed with ammonium in response to the presence or absence of the emergent macrophyte Glyceria maxima and the heterotrophic denitrifying bacterium P

  2. INHIBITION OF ALKYLBENZENE BIODEGRADATION UNDER DENITRIFYING CONDITIONS BY USING THE ACETYLENE BLOCK TECHNIQUE

    Addition of acetylene to microcosms simultaneously amended with nitrate and alkylbenzenes resulted in inhibition of the rate of alkylbenzene biodegradation under denitrifying conditions. Toluene, xylenes, and 1,2,4-trimethylbenzene were recalcitrant, whereas ethylbenzene was degr...

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

    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 μ-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.

  4. Highly diverse nirK genes comprise two major clades that harbour ammonium-producing denitrifiers

    2016-01-01

    Background Copper dependent nitrite reductase, NirK, catalyses the key step in denitrification, i.e. nitrite reduction to nitric oxide. Distinct structural NirK classes and phylogenetic clades of NirK-type denitrifiers have previously been observed based on a limited set of NirK sequences, however, their environmental distribution or ecological strategies are currently unknown. In addition, environmental nirK-type denitrifiers are currently underestimated in PCR-dependent surveys due to prime...

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

    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.)

  6. Feeding glycerol-enriched yeast culture improves lactation performance, energy status, and hepatic gluconeogenic enzyme expression of dairy cows during the transition period.

    Ye, G; Liu, J; Liu, Y; Chen, X; Liao, S F; Huang, D; Huang, K

    2016-06-01

    This study aimed to evaluate the effects of feeding glycerol-enriched yeast culture (GY) on feed intake, lactation performance, blood metabolites, and expression of some key hepatic gluconeogenic enzymes in dairy cows during the transition period. Forty-four multiparous transition Holstein cows were blocked by parity, previous 305-d mature equivalent milk yield, and expected calving date and randomly allocated to 4 dietary treatments: Control (no additive), 2 L/d of GY (75.8 g/L glycerol and 15.3 g/L yeast), 150 g/d of glycerol (G; 0.998 g/g glycerol), and 1 L/d of yeast culture (Y; 31.1 g/L yeast). All additives were top-dressed and hand mixed into the upper one-third of the total mixed ration in the morning from -14 to +28 d relative to calving. Results indicated that the DMI, NE intake, change of BCS, and milk yields were not affected by the treatments ( > 0.05). Supplementation of GY or Y increased milk fat percentages, milk protein percentages, and milk protein yields relative to the Control or G group ( 0.10). In conclusion, dietary GY or Y supplementation increased the milk fat and protein content of the cows in early lactation and GY or G supplementation improved the energy status as indicated by greater plasma glucose and lower plasma BHBA and NEFA concentrations and upregulated the hepatic gluconeogenic enzymes of dairy cows during the transition period. Feeding cows with a GY mixture in the peripartum period combined the effects of yeast on lactation performance and the effects of glycerol on energy status in dairy cows.

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

    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.

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

    Azabou, Samia; Mechichi, Tahar; Patel, Bharat K C; Sayadi, Sami

    2007-02-09

    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 1-20g/L phosphogypsum to sulfide with reduction of sulfate contained in 2g/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 (125ppm Zn and 100ppm Ni, W, Li and Al). The relative order for the inhibitory metal concentrations, based on the IC(50) values, was Cu, Te>Cd>Fe, Co, Mn>F, Se>Ni, Al, Li>Zn.

  9. Microbiological Denitrification and Denitrifying Activity of Paracoccus Denitrificans

    万曦; 万国江; 等

    2000-01-01

    With rapidly industrial and agricultural development,more and more fertilizers,chemicals and heavy ions will be discharged into lakes and rivers,which would cause lake eutrophication and quality deterioration in drinking water sources.Therefore,denitrification is essential for controlling the amounts of nitrogen,During the transformation process from nitrate to the end products-nitrogen and several intermediated[e.g.nitrite(NO2-),nitrous oxide(N2O) and nitric oxide(NO)]may be accumulated,which have more toxic influences on the environment.in This study,the denitrification effect of Paracoccus Denitrificans was examined on the changes between oxic and anoxic conditions at varying pH.At pH=7.5,denitrification proceeded well after 3 switches from oxic to anoxic conditions and vice versa,Production of N2 was constant and the amounts of NO2-,N2O and NO were extremely low.How ever,at pH=6.8,denitrification activity was inhitied and there large amounts of the intermaediates.The denitrifying bacteria decreased violently in dry weight and were washed out.

  10. Effect of denitrifying bacteria on the electrochemical reaction of activated carbon fiber in electrochemical biofilm system

    YING Diwen; JIA Jinping; ZHANG Lehua

    2007-01-01

    An electrochemical-activated denitrifying biofilm system consisting of activated carbon fiber electrodes immobilized with denitrifying bacteria film as cathode was studied.A revised model for an electrochemical-activated denitrifying biofilm was developed and validated by electrochemical analysis of cathodal polarization curves and nitrate consumption rate.The cathodal polarization curve and nitrate consumption rate were introduced to verify the rate of electrochemical reaction and the activity of denitrifying bacteria,respectively.It was shown that the denitrification process effectively strengthened the electrochemical reaction while the electron also intensified denitrification activity.Electron was transferred between electrochemical process and biological process not only by hydrogen molecule but also by new produced active hydrogen atom.Additionally,a parameter of apparent exchange current density was deprived from the cathodal polarization curve with high overpotential,and a new bio-effect current density was defined through statistical analysis,which was linearly dependent to the activity of denitrification bacteria.Activated carbon fiber (ACF) electrode was also found to be more suitable to the electrochemical denitrifying system compared with graphite and platinum.

  11. Positive role of nitrite as electron acceptor on anoxic denitrifying phosphorus removal process

    HUANG RongXin; LI Dong; LI XiangKun; BAO LinLin; JIANG AnXi; ZHANG Jie

    2007-01-01

    Literatures revealed that the electron acceptor-nitrite could be inhibitory or toxic in the denitrifying phosphorus removal process.Batch test experiments were used to investigate the inhibitory effect during the anoxic condition.The inoculated activated sludge was taken from a continuous double- sludge denitrifying phosphorus and nitrogen removal system.Nitrite was added at the anoxic stage.One time injection and sequencing batch injection were carried on in the denitrifying dephosphorus procedure.The results indicated that the nitrite concentration higher than 30 mg/L would inhibit the anoxic phosphate uptake severely, and the threshold inhibitory concentration was dependent on the characteristics of the activated sludge and the operating conditions; instead, lower than the inhibitory concentration would not be detrimental to anoxic phosphorus uptake, and it could act as good electron acceptor for the anoxic phosphate accumulated.Positive effects performed during the denitrifying biological dephosphorus all the time.The utility of nitrite as good electron acceptor would provide a new feasible way in the denitrifying phosphorus process.

  12. Impact of Land Use Management and Soil Properties on Denitrifier Communities of Namibian Savannas.

    Braker, Gesche; Matthies, Diethart; Hannig, Michael; Brandt, Franziska Barbara; Brenzinger, Kristof; Gröngröft, Alexander

    2015-11-01

    We studied potential denitrification activity and the underlying denitrifier communities in soils from a semiarid savanna ecosystem of the Kavango region in NE Namibia to help in predicting future changes in N(2)O emissions due to continuing changes of land use in this region. Soil type and land use (pristine, fallow, and cultivated soils) influenced physicochemical characteristics of the soils that are relevant to denitrification activity and N(2)O fluxes from soils and affected potential denitrification activity. Potential denitrification activity was assessed by using the denitrifier enzyme activity (DEA) assay as a proxy for denitrification activity in the soil. Soil type and land use influenced C and N contents of the soils. Pristine soils that had never been cultivated had a particularly high C content. Cultivation reduced soil C content and the abundance of denitrifiers and changed the composition of the denitrifier communities. DEA was strongly and positively correlated with soil C content and was higher in pristine than in fallow or recently cultivated soils. Soil type and the composition of both the nirK- and nirS-type denitrifier communities also influenced DEA. In contrast, other soil characteristics like N content, C:N ratio, and pH did not predict DEA. These findings suggest that due to greater availability of soil organic matter, and hence a more effective N cycling, the natural semiarid grasslands emit more N(2)O than managed lands in Namibia.

  13. Abundance and Diversity of Denitrifying and Anammox Bacteria in Seasonally Hypoxic and Sulfidic Sediments of the Saline Lake Grevelingen

    Lipsewers, Y.A.; Hopmans, E.C.; Meysman, F.J.R.; Sinninghe Damsté, J.S.; Villanueva, L.

    2016-01-01

    Denitrifying and anammox bacteria are involved in the nitrogen cycling in marine sediments but the environmental factors that regulate the relative importance of these processes are not well constrained. Here, we evaluated the abundance, diversity, and potential activity of denitrifying, anammox, an

  14. Differential Isotopic Fractionation during Cr(VI) Reduction by an Aquifer-Derived Bacterium under Aerobic versus Denitrifying Conditions

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

    2012-01-27

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

  15. 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.

    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.

  16. Factors affecting biological denitrifying dephosphatation in anaerobic/anoxic/aerobic sequencing batch reactor

    2007-01-01

    This study was conducted to verify and discuss the denitrifying dephosphatation under different levels of nitrate concentration and retention time of anoxic/aerobic process in a Sequencing Batch Reactor ( SBR ).The results of tests demonstrated that there were two kinds of phosphorus-accumulating organisms (PAOs) in the biological excess phosphorus removal (BEPR) system. One was non-DNPAOs that could only use oxygen as terminal electron acceptors, the other was denitrifying PAOs (DNPAOs) that could use both nitrate and oxygen as terminal electron acceptors. Phosphorus uptake efficiency could be attained under anoxic period ranging from 28.7%-96.7% in an anacrobic/anoxic/aerobic system. Experimental results showed that nitrate concentration and retention time of anoxic/aerobic process were the key factors affecting the course of denitrifying dephosphatation.

  17. Identification of a denitrifying bacterium and verification of its anaerobic ammonium oxidation ability

    HU; Baolan; ZHENG; Ping; LI; Jinye; XU; Xiangyang; JIN; Rencun

    2006-01-01

    A strain D3 of denitrifying bacterium was isolated from an anammox reactor, and identified as Pseudomonas mendocina based on the morphological and physiological assay, Vitek test,Biolog test, (G+C) mol% content, and 16S rDNA phylogenetic analysis. As a typical denitrifying bactration of 88.5 mg N/L. The optimal pH and growth temperature were 7.84 and 34.9℃, respectively.Strain D3 was able to oxidize ammonia under anaerobic condition. The maximum nitrate and ammoof ammonia to nitrate was 1:1.91. Electron microscopic observation revealed peculiar cell inclusions in strain D3. Because of its relation to anammox activity, strain D3 was presumed to be anammoxosome.The present investigation proved that denitrifying bacteria have the anammox ability, and the results have engorged the range of anammox populations.

  18. Effect of fish oil enriched enteral diet on inflammatory bowel disease tissues in organ culture: Differential effects on ulcerative colitis and Crohn's disease

    Doris Meister; Subrata Ghosh

    2005-01-01

    AIM: To investigate the influence of fish oil enriched enteral diet on intestinal tissues taken from Crohn's disease (CD), ulcerative colitis (UC) and non-inflamed non-IBD control patients in vitro.METHODS: Colonoscopic biopsies from patients with active CD (n = 4), active UC (n = 7), and non-inflamed non-IBD control patients (n = 4) were incubated (three dilutions of 1:20, 1:10, and 1:5) with Waymouth's culture medium and enteral elemental diet (EO28, SHS, Liverpool, UK) modified in the fatty acid composition with fish oil (EF) in an organ culture system for 24 h. In each experimental set-up, incubation with Waymouth's medium alone as control was included. Tissue viability was assessed by adding bromodeoxyuridine (BrdU) to the culture fluid and immunohistochemically staining for BrdU uptake. Cytokine ratio of IL-1ra/IL-1β (low ratio indicative of inflammation) and production of those cytokines as a percentage of medium control were assayed in the culture supernatant. RESULTS: Incubation of CD-affected tissue with EF (1:20, 1:10, and 1:5) modestly and non-significantly increased IL-1ra/IL-1β ratio as compared with medium control (CD 39.1±16.1; 26.5±7.8, 47.1±16.8 vs control 13.0±2.2), but incubation of UC-affected tissues increased IL-1ra/IL-1β ratio significantly in all three dilutions (UC 69.1±32.2, P<0.05; 76.1±36.4, P = 0.05;84.5±37.3, P<0.02; vs control 10.2±3.7). Incubation of non-inflamed non-IBD control tissue did not increase the IL-1ra/IL-1β ratio in any dilution compared to medium control (69.3±47.0, 54.1±30.6, 79.4±34.0 vs control 76.1±37.3). Average percentage production of IL-1β indexed against medium control was significantly less in UC after EF incubation as compared with CD (UC 24.0±4.8 vs CD 51.8±8.1; P<0.05). Average percentage production of IL-1ra was markedly higher in UC (135.9±3.4) than that in control patients (36.5±4.3) (P<0.0001).CONCLUSION: IBD tissues, after incubation with elemental diet modified in its

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

    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.

  20. Tillage Management and Seasonal Effects on Denitrifier Community Abundance, Gene Expression and Structure over Winter.

    Tatti, Enrico; Goyer, Claudia; Burton, David L; Wertz, Sophie; Zebarth, Bernie J; Chantigny, Martin; Filion, Martin

    2015-10-01

    Tillage effects on denitrifier communities and nitrous oxide (N2O) emissions were mainly studied during the growing season. There is limited information for the non-growing season, especially in northern countries where winter has prolonged periods with sub-zero temperatures. The abundance and structure of the denitrifier community, denitrification gene expression and N2O emissions in fields under long-term tillage regimes [no-tillage (NT) vs conventional tillage (CT)] were assessed during two consecutive winters. NT exerted a positive effect on nirK and nosZ denitrifier abundance in both winters compared to CT. Moreover, the two contrasting managements had an opposite influence on nirK and nirS RNA/DNA ratios. Tillage management resulted in different denitrifier community structures during both winters. Seasonal changes were observed in the abundance and the structure of denitrifiers. Interestingly, the RNA/DNA ratios were greater in the coldest months for nirK, nirS and nosZ. N2O emissions were not influenced by management but changed over time with two orders of magnitude increase in the coldest month of both winters. In winter of 2009-2010, emissions were mainly as N2O, whereas in 2010-2011, when soil temperatures were milder due to persistent snow cover, most emissions were as dinitrogen. Results indicated that tillage management during the growing season induced differences in denitrifier community structure that persisted during winter. However, management did not affect the active cold-adapted community structure.

  1. 一个硫酸盐还原细菌富集物对丁草胺的厌氧降解%Anaerobic degradation of butachlor by sulfate-reducing bacteria enrichment culture

    叶央芳; 杜宇峰

    2000-01-01

    An enrichment culture of sulfate-reducing bacteria,capable of anaerabic degrading butachlor,was obtained.The degradation kinetics of butachlor by the enrichment culture was determined and the optimum concentration of butachlor,the optimum pH and temperature for degradation of butachlor were observed..%通过多次富集培养,得到一个能有效厌氧降解丁草胺的硫酸盐还原细菌(SRB)富集物,并对该富集物的生长动力学以及生长的最适丁草胺浓度、最适pH和最适温度作了探讨.

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

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

    2008-01-01

    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 m......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...

  3. A combined approach for the enhanced detection and isolation of Bartonella species in dog blood samples: pre-enrichment liquid culture followed by PCR and subculture onto agar plates.

    Duncan, Ashlee W; Maggi, Ricardo G; Breitschwerdt, Edward B

    2007-05-01

    Historically, direct plating, lysis centrifugation, or freeze-thaw approaches have proven to be highly insensitive methods for confirming Bartonella species infection in dogs. A prospective study was designed to compare diagnostic methods for the detection of Bartonella using samples submitted to the Vector-Borne Disease Diagnostic Laboratory at North Carolina State University. Methods included indirect immunofluorescence assay, PCR, direct inoculation of a blood agar plate (trypticase soy agar with 5% rabbit blood), and inoculation into a novel pre-enrichment liquid medium, Bartonella/alpha-Proteobacteria growth medium (BAPGM). Sequential research efforts resulted in the development of a combinational approach consisting of pre-enrichment culture of Bartonella species in BAPGM, sub-inoculation of the liquid culture onto agar plates, followed by DNA amplification using PCR. The multi-faceted approach resulted in substantial improvement in the microbiological detection and isolation of Bartonella when compared to direct inoculation of a blood agar plate. Importantly, this approach facilitated the detection and subsequent isolation of both single and co-infections with two Bartonella species in the blood of naturally infected dogs. The use of a combinational approach of pre-enrichment culture and PCR may assist in the diagnostic confirmation of bartonellosis in dogs and other animals.

  4. The effects of co-contaminants and native wetland sediments on the activity and dominant transformation mechanisms of a 1,1,2,2-tetrachloroethane (TeCA)-degrading enrichment culture

    Lorah, Michelle M.; Schiffmacher, Emily N.; Becker, Jennifer G.; Voytek, Mary A.

    2016-01-01

    Bioremediation strategies, including bioaugmentation with chlorinated ethene-degrading enrichment cultures, have been successfully applied in the cleanup of subsurface environments contaminated with tetrachloroethene (PCE) and/or trichloroethene (TCE). However, these compounds are frequently found in the environment as components of mixtures that may also contain chlorinated ethanes and methanes. Under these conditions, the implementation of bioremediation may be complicated by inhibition effects, particularly when multiple dehalorespirers are present. We investigated the ability of the 1,1,2,2-tetrachloroethane (TeCA)-dechlorinating culture WBC-2 to biotransform TeCA alone, or a mixture of TeCA plus PCE and carbon tetrachloride (CT), in microcosms. The microcosms contained electron donors provided to biostimulate the added culture and sediment collected from a wetland where numerous “hotspots” of contamination with chlorinated solvent mixtures exist. The dominant TeCA biodegradation mechanism mediated by the WBC-2 culture in the microcosms was different in the presence of these wetland sediments than in the sediment-free enrichment culture or in previous WBC-2 bioaugmented microcosms and column tests conducted with wetland sediment collected at nearby sites. The co-contaminants and their daughter products also inhibited TeCA biodegradation by WBC-2. These results highlight the need to conduct biodegradability assays at new sites, particularly when multiple contaminants and dehalorespiring populations are present.

  5. Pyruvic Oxime Nitrification and Copper and Nickel Resistance by a Cupriavidus pauculus, an Active Heterotrophic Nitrifier-Denitrifier

    Miguel Ramirez

    2014-01-01

    Full Text Available Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammonium ion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N2 and nitrous oxide (N2O while heterotrophically nitrifying the organic substrate pyruvic oxime [CH3–C(NOH–COOH]. Neither N2 nor N2O were produced. Nucleotide and phylogenetic analyses indicated that the organism is a member of a genus (Cupriavidus known for its resistance to metals and its metabolism of xenobiotics. The microbe (a Cupriavidus pauculus designated as C. pauculus strain UM1 was examined for its ability to perform heterotrophic nitrification in the presence of Cu2+ and Ni2+ and to metabolize the xenobiotic phenol. The bacterium heterotrophically nitrified well when either 1 mM Cu2+ or 0.5 mM Ni2+ was present in either enriched or minimal medium. The organism also used phenol as a sole carbon source in either the presence or absence of 1 mM Cu2+ or 0.5 mM Ni2+. The ability of this isolate to perform a number of different metabolisms, its noteworthy resistance to copper and nickel, and its potential use as a bioremediation agent are discussed.

  6. Nitrogen Removal from Micro-Polluted Reservoir Water by Indigenous Aerobic Denitrifiers

    Ting-Lin Huang

    2015-04-01

    Full Text Available 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 × 104 to 2 × 107 cfu/mL and from 7.75 × 103 to 5.5 × 105 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

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

    Poulsen, Morten; Stief, Peter; Schramm, Andreas

    actively expressed in the gut contents of C. plumosus. The remaining increase may be due to the creation of 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...

  8. Effect of carbon source and nitrate concentration on denitrifying phosphorus removal by DPB sludge

    WANG Ya-yi; PENG Yong-zhen; Wang Shu-ying; PAN Mian-li

    2004-01-01

    Effect of added carbon source and nitrate concentration on the denitrifying phosphorus removal by DPB sludge was systematically studied using batch experiments, at the same time the variation of ORP was investigated.Results showed that the denitrifying and phosphorus uptake rate in anoxic phase increased with the high initial anaerobic carbon source addition. However once the initial COD concentration reached a certain level, which was in excess to the PHB saturation of poly-P bacteria, residual COD carried over to anoxic phase inhibited the subsequent denitrifying phosphorus uptake. Simultaneously, phosphate uptake continued until all nitrate was removed, following a slow endogenous release of phosphate. High nitrate concentration in anoxic phase increased the initial denitrifying phosphorus rate. Once the nitrate was exhausted, phosphate uptake changed to release. Moreover, the time of this turning point occurred later with the higher nitrate addition. On the other hand, through on-line monitoring the variation of the ORP with different initial COD concentration , it was found ORP could be used as a control parameter for phosphorus release, but it is impossible to utilize ORP for controlling the denitrificaion and anoxic phosphorus uptake operations.

  9. Optimization of denitrifying bioreactor performance with agricultural residue-based filter media

    Denitrification bioreactors are a promising technology for mitigation of nitrate-nitrogen (NO3-N) losses in subsurface drainage water. Bioreactors are constructed with carbon substrates, typically wood chips, to provide a substrate for denitrifying microorganisms. Columns were packed with wood chips...

  10. Influence of carbon source and temperature on the denitrifying phosphorus removal process

    WANG Yayi; WANG Shuying; PENG Yongzhen; Zhu Guibing; LING Yunfang

    2007-01-01

    To supply the valuable operating parameters for the popular usage of the new denitrifying phosphors removal process,it is essential to study the dominant biochemical reactions and the characteristics of denitriflying phosphorus removing bacteria(DPB).Thus,parallel batch experiments using DPB sludge were carried out to assess the effect of substrates(sewage,HAc,and endogenous carbon source)on denitriflying dephosphorus removal efficiency in this study.The results showed that the initial specific phosphorus release rate increased with the high concentration of the short-chain volatile fatty acids ratio in the influent,and sufficient phosphorus was released by DPB.This improved the subsequent denitrification and phosphorus uptake efficiency.The specific endogenous denitrification mainly relies on the internal carbon source(PHB)stored by poly-P bacteria.Denitrifying phosphorus removing bacteria were very hungry when the internal PHB was consumed.Consequently,the specific endogenous denitrification rate was low and the phosphorus uptake did not happen.On the other hand,in the experiment,the denitrifying phosphorus removal performance under two temperature conditions(8-10℃ and 25-26℃)was also investigated and analyzed.It was found that the lower temperature decreased the specific phosphorus release and uptake rate,but did not inhibit the denitrifying phosphorus removal completely.Therefore,the negative influence of the low temperature on the overall phosphorus removal was not significant.

  11. Optimizing hydraulic retention times in denitrifying woodchip bioreactors treating recirculating aquaculture system wastewater

    The performance of wood-based denitrifying bioreactors to treat high-nitrate wastewaters from aquaculture systems has not previously been demonstrated. Four pilot-scale woodchip bioreactors (approximately 1:10 scale) were constructed and operated for 268 d to determine the optimal range of design hy...

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

    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...

  13. Carbon amendment and soil depth affect the distribution and abundance of denitrifiers in agricultural soils.

    Barrett, M; Khalil, M I; Jahangir, M M R; Lee, C; Cardenas, L M; Collins, G; Richards, K G; O'Flaherty, V

    2016-04-01

    The nitrite reductase (nirS and nirK) and nitrous oxide reductase-encoding (nosZ) genes of denitrifying populations present in an agricultural grassland soil were quantified using real-time polymerase chain reaction (PCR) assays. Samples from three separate pedological depths at the chosen site were investigated: horizon A (0-10 cm), horizon B (45-55 cm), and horizon C (120-130 cm). The effect of carbon addition (treatment 1, control; treatment 2, glucose-C; treatment 3, dissolved organic carbon (DOC)) on denitrifier gene abundance and N2O and N2 fluxes was determined. In general, denitrifier abundance correlated well with flux measurements; nirS was positively correlated with N2O, and nosZ was positively correlated with N2 (P soil (GCC) varied in response to carbon type amendment (P soil depth directly affected bacterial, archaeal, and denitrifier abundance, possibly due to changes in soil carbon availability with depth.

  14. Rapid identification of Salmonella serovars in feces by specific detection of virulence genes, invA and spvC, by an enrichment broth culture-multiplex PCR combination assay.

    Chiu, C H; Ou, J T

    1996-10-01

    In order to make a rapid and definite diagnosis of Salmonella enteritis in children, an enrichment broth culture-multiplex PCR combination assay was devised to identify Salmonella serovars directly from fecal samples. Two pairs of oligonucleotide primers were prepared according to the sequences of the chromosomal invA and plasmid spvC genes. PCR with these two primers would produce either one amplicon (from the invA gene) or two amplicons (from the invA and spvC genes), depending on whether or not the Salmonella bacteria contained a virulence plasmid. The fecal sample was diluted 10- to 20-fold into gram-negative enrichment broth and incubated to eliminate inhibitory compounds and also to allow selective enrichment of the bacteria. One or two amplicons were obtained, the expected result if Salmonella bacteria were present. The detection limit of this PCR was about 200 bacteria per reaction mixture. The primers were specific, as no amplification products were obtained with 18 species and 22 isolates of non-Salmonella bacteria tested which could be present in the feces or cause contamination. In contrast, when 23 commonly seen Salmonella serovars (38 isolates) were tested, all were shown to carry the invA gene and seven concomitantly harbored the spvC gene of the virulence plasmid. This assay was applied to the diagnosis of Salmonella enteritis in 57 children who were suffering from mucoid and/or bloody diarrhea. Of the 57 children, 38 were PCR positive and 22 were culture positive. There were two culture-positive samples that were not detected by PCR. Thus, this PCR assay showed an efficiency of 95% (38 of 40), which is much higher than the 60% (24 of 40) by culture alone. Not only is this method more sensitive, rapid, and efficient but it will cause only an incremental increase in the cost of stool processing, since enrichment cultivation of fecal samples from diarrheal patients using gram-negative enrichment broth is a routine practice for identification in many

  15. Soil denitrifier community size changes with land use change to perennial bioenergy cropping systems

    Thompson, Karen A.; Deen, Bill; Dunfield, Kari E.

    2016-10-01

    Dedicated biomass crops are required for future bioenergy production. However, the effects of large-scale land use change (LUC) from traditional annual crops, such as corn-soybean rotations to the perennial grasses (PGs) switchgrass and miscanthus, on soil microbial community functioning is largely unknown. Specifically, ecologically significant denitrifying communities, which regulate N2O production and consumption in soils, may respond differently to LUC due to differences in carbon (C) and nitrogen (N) inputs between crop types and management systems. Our objective was to quantify bacterial denitrifying gene abundances as influenced by corn-soybean crop production compared to PG biomass production. A field trial was established in 2008 at the Elora Research Station in Ontario, Canada (n  =  30), with miscanthus and switchgrass grown alongside corn-soybean rotations at different N rates (0 and 160 kg N ha-1) and biomass harvest dates within PG plots. Soil was collected on four dates from 2011 to 2012 and quantitative PCR was used to enumerate the total bacterial community (16S rRNA) and communities of bacterial denitrifiers by targeting nitrite reductase (nirS) and N2O reductase (nosZ) genes. Miscanthus produced significantly larger yields and supported larger nosZ denitrifying communities than corn-soybean rotations regardless of management, indicating large-scale LUC from corn-soybean to miscanthus may be suitable in variable Ontario climatic conditions and under varied management, while potentially mitigating soil N2O emissions. Harvesting switchgrass in the spring decreased yields in N-fertilized plots, but did not affect gene abundances. Standing miscanthus overwinter resulted in higher 16S rRNA and nirS gene copies than in fall-harvested crops. However, the size of the total (16S rRNA) and denitrifying bacterial communities changed differently over time and in response to LUC, indicating varying controls on these communities.

  16. Porównawcze badania nad występowaniem bakterii w hydroponicznych uprawach sałaty (Lactuca sativa L. z azotanowaą i amonową formą azotu w pożywce [Comparative studies on the occurrence of bacteria in hydroponic cultures of lettuce (Lactuca sativa L. enriched with nitrate or ammonia forms of nitrogen in the nutrient medium

    Z. Kobierzyńska-Gołąb

    2015-06-01

    Full Text Available The experiment demonstrated the greatest number of bacteria on the surface of roots immersed in nutrient solution, next on the epidermis of the parts of roots remaining in the air space above the nutrient solution and on the roots growing in the seed-bed; a smaller number in the seed-bed itself and the smallest number in the nutrient solution. The population of bacteria consisted of up to 90% short rod of bacilli. The total number of bacteria in hydroponic culture with ammonium was higher than in that with nitrate. As a rule the bacteria belonging to the separate physiological groups, participating in nitrogen metabolism (ammonifying, proteolytic, proteinizing, denitrifying and oligonitrophilic bacteria appeared to be more numerus in the culture with ammonium than in that with nitrate. The growth of plants in hydroponic culture with ammonium was weaker than in that with nitrate.

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

    Vieira-Dalodé, G.; Madodé, Y.E.; Hounhouigan, J.

    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 eva...

  18. In situ detection of denitrifying bacteria by mRNA-targeted nucleic acid probes and catalyzed reporter deposition

    Kofoed, Michael Vedel; Stief, Peter; Poulsen, Morten;

    In situ detection of denitrifying bacteria by mRNA-targeted nucleic acid probes and catalyzed reporter deposition   Michael V.W. Kofoed, Peter Stief, Morten Poulsen, and Andreas Schramm Department of Biological Sciences, Microbiology, University of Aarhus, Denmark Denitrification, the sequential...... reduction of nitrate to dinitrogen gas, is essential for the removal of fixed nitrogen from natural and engineered ecosystems. However, community structure and activity dynamics of denitrifying bacteria in most systems are poorly understood, partially due to difficulties in identifying and quantifying...... (active) denitrifiers. The goal of this study was therefore to develop a protocol for the in situ detection of denitrifying bacterial cells by targeting the mRNA of denitrification genes, hereby linking denitrification activity directly to the single-cell level. Target genes were narG (encoding nitrate...

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

    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

  20. 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.

    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.

  1. Denitrification potential under different fertilization regimes is closely coupled with changes in the denitrifying community in a black soil.

    Yin, Chang; Fan, Fenliang; Song, Alin; Cui, Peiyuan; Li, Tingqiang; Liang, Yongchao

    2015-07-01

    Preferable inorganic fertilization over the last decades has led to fertility degradation of black soil in Northeast China. However, how fertilization regimes impact denitrification and its related bacterial community in this soil type is still unclear. Here, taking advantage of a suit of molecular ecological tools in combination of assaying the potential denitrification (DP), we explored the variation of activity, community structure, and abundance of nirS and nirK denitrifiers under four different fertilization regimes, namely no fertilization control (N0M0), organic pig manure (N0M1), inorganic fertilization (N1M0), and combination of inorganic fertilizer and pig manure (N1M1). The results indicated that organic fertilization increased DP, but inorganic fertilization had no impacts. The increase of DP was mirrored by the shift of nirS denitrifiers' community structure but not by that of nirK denitrifiers'. Furthermore, the change of DP coincided with the variation of abundances of both denitrifiers. Shifts of community structure and abundance of nirS and nirK denitrifiers were correlated with the change of soil pH, total nitrogen (TN), organic matter (OM), C:P, total phosphorus (TP), and available phosphorus (Olsen P). Our results suggest that the change of DP under these four fertilization regimes was closely related to the shift of denitrifying bacteria communities resulting from the variation of properties in the black soil tested.

  2. Self-Protected Nitrate Reducing Culture for Intrinsic Repair of Concrete Cracks

    Yusuf Cagatay Ersan

    2015-11-01

    Full Text Available 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 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(NO32 and Ca(HCOO2 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.

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

    Erşan, 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

  4. Kinetics of Nitrate Utilization by Mixed Populations of Denitrifying Bacteria †

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

    1989-01-01

    Kinetics of nitrate utilization by mixed bacterial populations from two agricultural soils and a pond sediment in Kentucky were measured by using progress curves of nitrous oxide production. Nitrous oxide production from anaerobic soil and sediment slurries containing added nitrate and acetylene exhibited first-order kinetics. Nitrate affinity (Km) for mixed populations of denitrifying bacteria in unfertilized agricultural soils and pond sediments ranged from 1.8 to 13.7 μM. The affinity of b...

  5. Disentangling the rhizosphere effect on nitrate reducers and denitrifiers: insight into the role of root exudates.

    Henry, S; Texier, S; Hallet, S; Bru, D; Dambreville, C; Chèneby, D; Bizouard, F; Germon, J C; Philippot, L

    2008-11-01

    To determine to which extent root-derived carbon contributes to the effects of plants on nitrate reducers and denitrifiers, four solutions containing different proportions of sugar, organic acids and amino acids mimicking maize root exudates were added daily to soil microcosms at a concentration of 150 microg C g(-1) of soil. Water-amended soils were used as controls. After 1 month, the size and structure of the nitrate reducer and denitrifier communities were analysed using the narG and napA, and the nirK, nirS and nosZ genes as molecular markers respectively. Addition of artificial root exudates (ARE) did not strongly affect the structure or the density of nitrate reducer and denitrifier communities whereas potential nitrate reductase and denitrification activities were stimulated by the addition of root exudates. An effect of ARE composition was also observed on N(2)O production with an N(2)O:(N(2)O + N(2)) ratio of 0.3 in microcosms amended with ARE containing 80% of sugar and of 1 in microcosms amended with ARE containing 40% of sugar. Our study indicated that ARE stimulated nitrate reduction or denitrification activity with increases in the range of those observed with the whole plant. Furthermore, we demonstrated that the composition of the ARE affected the nature of the end-product of denitrification and could thus have a putative impact on greenhouse gas emissions.

  6. Fertilization stimulates anaerobic fuel degradation of antarctic soils by denitrifying microorganisms.

    Powell, Shane M; Ferguson, Susan H; Snape, Ian; Siciliano, Steven D

    2006-03-15

    Human activities in the Antarctic have resulted in hydrocarbon contamination of these fragile polar soils. Bioremediation is one of the options for remediation of these sites. However, little is known about anaerobic hydrocarbon degradation in polar soils and the influence of bioremediation practices on these processes. Using a field trial at Old Casey Station, Antarctica, we assessed the influence of fertilization on the anaerobic degradation of a 20-year old fuel spill. Fertilization increased hydrocarbon degradation in both anaerobic and aerobic soils when compared to controls, but was of most benefit for anaerobic soils where evaporation was negligible. This increased biodegradation in the anaerobic soils corresponded with a shift in the denitrifier community composition and an increased abundance of denitrifiers and benzoyl-CoA reductase. A microcosm study using toluene and hexadecane confirmed the degradative capacity within these soils under anaerobic conditions. It was observed that fertilized anaerobic soil degraded more of this hydrocarbon spike when incubated anaerobically than when incubated aerobically. We conclude that denitrifiers are actively involved in hydrocarbon degradation in Antarctic soils and that fertilization is an effective means of stimulating their activity. Further, when communities stimulated to degrade hydrocarbons under anaerobic conditions are exposed to oxygen, hydrocarbon degradation is suppressed. The commonly accepted belief that remediation of polar soils requires aeration needs to be reevaluated in light of this new data.

  7. [Analysis on Diversity of Denitrifying Microorganisms in Sequential Batch Bioreactor Landfill].

    Li, Wei-Hua; Sun, Ying-Jie; Liu, Zi-Liang; Ma, Qiang; Yang, Qiang

    2016-01-15

    A denitrification functional microorganism gene clone library (amoA, nosZ) and the PCR-RFLP technology was constructed to investigate the microbial diversity of denitrifying microorganisms in the late period of stabilization of sequential batch bioreactor landfill. The results indicated that: the bacterial diversity of ammonia oxidizing bacteria in the aged refuse reactor was very high, and most of them were unknown groups, also, all bacteria were unculturable or had not been isolated. The phylogenetic analysis suggested that the dominant ammonia oxidizing bacteria were presumably Nitrosomonas of 6-Proteobacteria. The diversity of denitrifying bacteria in fresh refuse reactor was abundant, which mainly included Thauera and Thiobacillus of 6-Proteobacteria. As Thauera sp. has the denitrification characteristics under the condition of aerobic while Thiobacillus denitrificans has the autotrophic denitrification characteristics, it was speculated that aerobic denitrification and autotrophic denitrification might be the main pathways for nitrogen removal in the fresh refuse reactor at the late period of stabilization. Additionally, another group in the gene clone library of denitrifying bacteria may be classified as Bradyrhizobiaceae of alpha-Proteobacteria.

  8. Enrichment of Secondary Wastewater Sludge for Production of Hydrogen from Crude Glycerol and Comparative Evaluation of Mono-, Co- and Mixed-Culture Systems

    Vinayak Laxman Pachapur

    2016-01-01

    Full Text Available Anaerobic digestion using mixed-culture with broader choice of pretreatments for hydrogen (H2 production was investigated. Pretreatment of wastewater sludge by five methods, such as heat, acid, base, microwave and chloroform was conducted using crude glycerol (CG as substrate. Results for heat treatment (100 °C for 15 min showed the highest H2 production across the pretreatment methods with 15.18 ± 0.26 mmol/L of medium at 30 °C in absence of complex media and nutrient solution. The heat-pretreated inoculum eliminated H2 consuming bacteria and produced twice as much as H2 as compared to other pretreatment methods. The fermentation conditions, such as CG concentration (1.23 to 24 g/L, percentage of inoculum size (InS (1.23% to 24% v/v along with initial pH (2.98 to 8.02 was tested using central composite design (CCD with H2 production as response parameter. The maximum H2 production of 29.43 ± 0.71 mmol/L obtained at optimum conditions of 20 g/L CG, 20% InS and pH 7. Symbiotic correlation of pH over CG and InS had a significant (p-value: 0.0011 contribution to H2 production. The mixed-culture possessed better natural acclimatization activity for degrading CG, at substrate inhibition concentration and provided efficient inoculum conditions in comparison to mono- and co-culture systems. The heat pretreatment step used across mixed-culture system is simple, cheap and industrially applicable in comparison to mono-/co-culture systems for H2 production.

  9. Enrichment of Secondary Wastewater Sludge for Production of Hydrogen from Crude Glycerol and Comparative Evaluation of Mono-, Co- and Mixed-Culture Systems.

    Pachapur, Vinayak Laxman; Kutty, Prianka; Brar, Satinder Kaur; Ramirez, Antonio Avalos

    2016-01-13

    Anaerobic digestion using mixed-culture with broader choice of pretreatments for hydrogen (H₂) production was investigated. Pretreatment of wastewater sludge by five methods, such as heat, acid, base, microwave and chloroform was conducted using crude glycerol (CG) as substrate. Results for heat treatment (100 °C for 15 min) showed the highest H₂ production across the pretreatment methods with 15.18 ± 0.26 mmol/L of medium at 30 °C in absence of complex media and nutrient solution. The heat-pretreated inoculum eliminated H₂ consuming bacteria and produced twice as much as H₂ as compared to other pretreatment methods. The fermentation conditions, such as CG concentration (1.23 to 24 g/L), percentage of inoculum size (InS) (1.23% to 24% v/v) along with initial pH (2.98 to 8.02) was tested using central composite design (CCD) with H₂ production as response parameter. The maximum H₂ production of 29.43 ± 0.71 mmol/L obtained at optimum conditions of 20 g/L CG, 20% InS and pH 7. Symbiotic correlation of pH over CG and InS had a significant (p-value: 0.0011) contribution to H₂ production. The mixed-culture possessed better natural acclimatization activity for degrading CG, at substrate inhibition concentration and provided efficient inoculum conditions in comparison to mono- and co-culture systems. The heat pretreatment step used across mixed-culture system is simple, cheap and industrially applicable in comparison to mono-/co-culture systems for H₂ production.

  10. Effect of a Semi-Purified Oligosaccharide-Enriched Fraction from Caprine Milk on Barrier Integrity and Mucin Production of Co-Culture Models of the Small and Large Intestinal Epithelium

    Alicia M. Barnett

    2016-05-01

    Full Text Available Caprine milk contains the highest amount of oligosaccharides among domestic animals, which are structurally similar to human milk oligosaccharides (HMOs. This suggests caprine milk oligosaccharides may offer similar protective and developmental effects to that of HMOs. However, to date, studies using oligosaccharides from caprine milk have been limited. Thus, this study aimed to examine the impact of a caprine milk oligosaccharide-enriched fraction (CMOF on barrier function of epithelial cell co-cultures of absorptive enterocytes (Caco-2 cells and mucus-secreting goblet cells (HT29-MTX cells, that more closely simulate the cell proportions found in the small (90:10 and large intestine (75:25. Treatment of epithelial co-cultures with 0.4, 1.0, 2.0 and 4.0 mg/mL of CMOF was shown to have no effect on metabolic activity but did enhance cell epithelial barrier integrity as measured by trans-epithelial electrical resistance (TEER, in a dose-dependent manner. The CMOF at the maximum concentration tested (4.0 mg/mL enhanced TEER, mucin gene expression and mucin protein abundance of epithelial co-cultures, all of which are essential components of intestinal barrier function.

  11. Phylogenetic and metabolic diversity of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-transforming bacteria in strictly anaerobic mixed cultures enriched on RDX as nitrogen source.

    Zhao, Jian-Shen; Spain, Jim; Hawari, Jalal

    2003-11-01

    Five obligate anaerobes that were most closely related to Clostridium bifermentans, Clostridium celerecrescens, Clostridium saccharolyticum, Clostridium butyricum and Desulfovibrio desulfuricans by their 16S rRNA genes sequences were isolated from enrichment cultures using hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) as a nitrogen source. The above isolates transformed RDX at rates of 24.0, 5.4, 6.2, 2.5, 5.5 mumol h(-1) g (dry weight) of cells(-1), respectively, to nitrite, formaldehyde, methanol, and nitrous oxide. The present results indicate that clostridia are major strains responsible for RDX removal, and all isolates seemed to mainly transform RDX via its initial reduction to MNX and subsequent denitration. Since clostridia are commonly present in soil, we suggest that they may contribute to the removal of RDX in the subsurface (anoxic) soil.

  12. Predominance of Viable Spore-Forming Piezophilic Bacteria in High-Pressure Enrichment Cultures from ~1.5 to 2.4 km-Deep Coal-Bearing Sediments below the Ocean Floor

    Fang, Jiasong; Kato, Chiaki; Runko, Gabriella M.; Nogi, Yuichi; Hori, Tomoyuki; Li, Jiangtao; Morono, Yuki; Inagaki, Fumio

    2017-01-01

    Phylogenetically diverse microorganisms have been observed in marine subsurface sediments down to ~2.5 km below the seafloor (kmbsf). However, very little is known about the pressure-adapted and/or pressure-loving microorganisms, the so called piezophiles, in the deep subseafloor biosphere, despite that pressure directly affects microbial physiology, metabolism, and biogeochemical processes of carbon and other elements in situ. In this study, we studied taxonomic compositions of microbial communities in high-pressure incubated sediment, obtained during the Integrated Ocean Drilling Program (IODP) Expedition 337 off the Shimokita Peninsula, Japan. Analysis of 16S rRNA gene-tagged sequences showed that members of spore-forming bacteria within Firmicutes and Actinobacteria were predominantly detected in all enrichment cultures from ~1.5 to 2.4 km-deep sediment samples, followed by members of Proteobacteria, Acidobacteria, and Bacteroidetes according to the sequence frequency. To further study the physiology of the deep subseafloor sedimentary piezophilic bacteria, we isolated and characterized two bacterial strains, 19R1-5 and 29R7-12, from 1.9 and 2.4 km-deep sediment samples, respectively. The isolates were both low G+C content, gram-positive, endospore-forming and facultative anaerobic piezophilic bacteria, closely related to Virgibacillus pantothenticus and Bacillus subtilis within the phylum Firmicutes, respectively. The optimal pressure and temperature conditions for growth were 20 MPa and 42°C for strain 19R1-5, and 10 MPa and 43°C for strain 29R7-12. Bacterial (endo)spores were observed in both the enrichment and pure cultures examined, suggesting that these piezophilic members were derived from microbial communities buried in the ~20 million-year-old coal-bearing sediments after the long-term survival as spores and that the deep biosphere may host more abundant gram-positive spore-forming bacteria and their spores than hitherto recognized. PMID:28220112

  13. Characteristics of self-alkalization in high-rate denitrifying automatic circulation (DAC) reactor fed with methanol and sodium acetate.

    Li, Wei; Zheng, Ping; Guo, Jun; Ji, Junyuan; Zhang, Meng; Zhang, Zonghe; Zhan, Enchao; Abbas, Ghulam

    2014-02-01

    Denitrification is a self-alkalization process. In this experiment, the characteristics of self-alkalization in high-rate heterotrophic denitrifying automatic circulation (DAC) reactor fed with methanol and sodium acetate were investigated, respectively. The results showed that, (1) The self-alkalization of high-rate denitrifying reactors was remarkably strong both with methanol and sodium acetate as carbon sources, while the effluent pH was much lower than the stoichiometric values and the malfunction from self-alkalization of denitrification was far less serious than expected. (2) The self-adaptation of the reactors was attributed to the neutralization of carbon dioxide (oxidization product of organic matter) and the self-adaptation of denitrifying sludge. The formation and discharge of calcium carbonate precipitates gave rise to lower effluent pH and alkalinity than the stoichiometric values.

  14. Moving Denitrifying Bioreactors beyond Proof of Concept: Introduction to the Special Section.

    Christianson, Laura E; Schipper, Louis A

    2016-05-01

    Denitrifying bioreactors are organic carbon-filled excavations designed to enhance the natural process of denitrification for the simple, passive treatment of nitrate-nitrogen. Research on and installation of these bioreactors has accelerated within the past 10 years, particularly in watersheds concerned about high nonpoint-source nitrate loads and also for tertiary wastewater treatment. This special section, inspired by the meeting of the Managing Denitrification in Agronomic Systems Community at the 2014 Annual Meeting of the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, aims to firmly establish that denitrifying bioreactors for treatment of nitrate in drainage waters, groundwater, and some wastewaters have moved beyond the proof of concept. This collection of 14 papers expands the peer-reviewed literature of denitrifying bioreactors into new locations, applications, and environmental conditions. There is momentum behind the pairing of wood-based bioreactors with other media (biochar, corn cobs) and in novel designs (e.g., use within treatment trains or use of baffles) to broaden applicability into new kinds of waters and pollutants and to improve performance under challenging field conditions such as cool early season agricultural drainage. Concerns about negative bioreactor by-products (nitrous oxide and hydrogen sulfide emissions, start-up nutrient flushing) are ongoing, but this translates into a significant research opportunity to develop more advanced designs and to fine tune management strategies. Future research must think more broadly to address bioreactor impacts on holistic watershed health and greenhouse gas balances and to facilitate collaborations that allow investigation of mechanisms within the bioreactor "black box."

  15. Marine Oxygen-Deficient Zones Harbor Depauperate Denitrifying Communities Compared to Novel Genetic Diversity in Coastal Sediments.

    Bowen, Jennifer L; Weisman, David; Yasuda, Michie; Jayakumar, Amal; Morrison, Hilary G; Ward, Bess B

    2015-08-01

    Denitrification is a critically important biogeochemical pathway that removes fixed nitrogen from ecosystems and thus ultimately controls the rate of primary production in nitrogen-limited systems. We examined the community structure of bacteria containing the nirS gene, a signature gene in the denitrification pathway, from estuarine and salt marsh sediments and from the water column of two of the world's largest marine oxygen-deficient zones (ODZs). We generated over 125,000 nirS gene sequences, revealing a large degree of genetic diversity including 1,815 unique taxa, the vast majority of which formed clades that contain no cultured representatives. These results underscore how little we know about the genetic diversity of metabolisms underlying this critical biogeochemical pathway. Marine sediments yielded 1,776 unique taxa when clustered at 95 % sequence identity, and there was no single nirS denitrifier that was a competitive dominant; different samples had different highly abundant taxa. By contrast, there were only 39 unique taxa identified in samples from the two ODZs, and 99 % of the sequences belonged to 5 or fewer taxa. The ODZ samples were often dominated by nirS sequences that shared a 92 % sequence identity to a nirS found in the anaerobic ammonium-oxidizing (anammox) genus Scalindua. This sequence was abundant in both ODZs, accounting for 38 and 59 % of all sequences, but it was virtually absent in marine sediments. Our data indicate that ODZs are remarkably depauperate in nirS genes compared to the remarkable genetic richness found in coastal sediments.

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

    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.

  17. Survival of the North American strain of viral hemorrhagic septicemia virus (VHSV) in filtered seawater and seawater containing ovarian fluid, crude oil and serum-enriched culture medium

    Kocan, R.M.; Hershberger, P.K.; Elder, N.E.

    2001-01-01

     The North American strain of viral hemorrhagic septicemia virus (NA-VHSV) could be recovered for up to 40 h in natural filtered seawater (27 ppt) with a 50% loss of infectivity after approximately 10 h at 15°C. Addition of 10 ppb North Slope crude oil to the seawater had no effect on virus survival. However, when various concentrations of teleost ovarian fluid were added to seawater, virus could be recovered after 72 h at 0.01% ovarian fluid and after 96 h at 1.0%. When cell culture medium supplemented with 10% fetal bovine serum was added to the seawater, 100% of the virus could be recovered for the first 15 d and 60% of the virus remained after 36 d. These findings quantify NA-VHSV infectivity in natural seawater and demonstrate that ovarian fluid, which occurs naturally during spawning events, significantly prolongs the survival and infectivity of the virus. The extended stabilization of virus in culture medium supplemented with serum allows for low titer field samples to be collected and transported in an unfrozen state without significant loss of virus titer.

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

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

    is limited1. Flexible denitrifiers play a crucial role in the cycling of nitrogen in the aquatic environment and are particularly significant in estuaries where they help regulate nitrogen transport to the oceans2,3 and maintain the integrity... & DENITRIFYING BACTERIA 589 et al, 200124 have reported a regulation of pH in estuaries on account of various inherent biological processes and soil water interactions. On the other hand, the temperature was noted to vary with the seasons with 27-28°C...

  19. cultural

    Irene Kreutz

    2006-01-01

    Full Text Available Es un estudio cualitativo que adoptó como referencial teorico-motodológico la antropología y la etnografía. Presenta las experiencias vivenciadas por mujeres de una comunidad en el proceso salud-enfermedad, con el objetivo de comprender los determinantes sócio-culturales e históricos de las prácticas de prevención y tratamiento adoptados por el grupo cultural por medio de la entrevista semi-estructurada. Los temas que emergieron fueron: la relación entre la alimentación y lo proceso salud-enfermedad, las relaciones con el sistema de salud oficial y el proceso salud-enfermedad y lo sobrenatural. Los dados revelaron que los moradores de la comunidad investigada tienen un modo particular de explicar sus procedimientos terapéuticos. Consideramos que es papel de los profesionales de la salud en sus prácticas, la adopción de abordajes o enfoques que consideren al individuo en su dimensión sócio-cultural e histórica, considerando la enorme diversidad cultural en nuestro país.

  20. Polyphasic characterization of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (p(HB-co-HV)) metabolizing and denitrifying Acidovorax sp. strains.

    Schloe, K; Gillis, M; Hoste, B; Pot, B; Vancanneyt, M; Mergaert, J; Swings, J; Biedermann, J; Süssmuth, R

    2000-10-01

    For the purpose of denitrification in small drinking water plants, a bacterial mixed population was isolated from a packed bed column bioreactor with poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P(HB-co-HV)) as a substrate for the denitrification of ground water (10 degrees C). Isolates 2nIII from the mixed culture, with the ability to denitrify and metabolize P(HB-co-HV), were used as starter cultures for the elimination of nitrate in ground water. The strains were characterized by diverse techniques. Classical phenotypic studies lead to rRNA group III of the genus Pseudomonas. Results obtained by molecular techniques demonstrated that the 2nIII strains are members of the Comamonadaceae and shows similarities to the genus Acidovorax. However, an integration of the 2nIII isolates within one of the known Acidovorax species is not possible for the moment. The 2nIII starter cultures clustered close to Av. temperans according to their whole cell proteins and fatty acids, whereas in DNA/DNA hybridization no significant DNA binding (< 25%) was found. In contrast a significant but low degree of DNA/DNA hybridization was found between the 2nIII strains and Av. facilis and Av. delafieldii. Our polyphasic results lead to the conclusion that the 2nIII strains may constitute a separate Acicdovorax species.

  1. Construction and screening of metagenomic libraries derived from enrichment cultures: generation of a gene bank for genes conferring alcohol oxidoreductase activity on Escherichia coli.

    Knietsch, Anja; Waschkowitz, Tanja; Bowien, Susanne; Henne, Anke; Daniel, Rolf

    2003-03-01

    Enrichment of microorganisms with special traits and the construction of metagenomic libraries by direct cloning of environmental DNA have great potential for identifying genes and gene products for biotechnological purposes. We have combined these techniques to isolate novel genes conferring oxidation of short-chain (C(2) to C(4)) polyols or reduction of the corresponding carbonyls. In order to favor the growth of microorganisms containing the targeted genes, samples collected from four different environments were incubated in the presence of glycerol and 1,2-propanediol. Subsequently, the DNA was extracted from the four samples and used to construct complex plasmid libraries. Approximately 100,000 Escherichia coli strains of each library per test substrate were screened for the production of carbonyls from polyols on indicator agar. Twenty-four positive E. coli clones were obtained during the initial screen. Sixteen of them contained a plasmid (pAK101 to pAK116) which conferred a stable carbonyl-forming phenotype. Eight of the positive clones exhibited NAD(H)-dependent alcohol oxidoreductase activity with polyols or carbonyls as the substrates in crude extracts. Sequencing revealed that the inserts of pAK101 to pAK116 encoded 36 complete and 17 incomplete presumptive protein-encoding genes. Fifty of these genes showed similarity to sequenced genes from a broad collection of different microorganisms. The genes responsible for the carbonyl formation of E. coli were identified for nine of the plasmids (pAK101, pAK102, pAK105, pAK107 to pAK110, pAK115, and pAK116). Analyses of the amino acid sequences deduced from these genes revealed that three (orf12, orf14, and orf22) encoded novel alcohol dehydrogenases of different types, four (orf5, sucB, fdhD, and yabF) encoded novel putative oxidoreductases belonging to groups distinct from alcohol dehydrogenases, one (glpK) encoded a putative glycerol kinase, and one (orf1) encoded a protein which showed no similarity to any

  2. Responses of bacterial community structure and denitrifying bacteria in biofilm to submerged macrophytes and nitrate

    Zhang, Songhe; Pang, Si; Wang, Peifang; Wang, Chao; Guo, Chuan; Addo, Felix Gyawu; Li, Yi

    2016-10-01

    Submerged macrophytes play important roles in constructed wetlands and natural water bodies, as these organisms remove nutrients and provide large surfaces for biofilms, which are beneficial for nitrogen removal, particularly from submerged macrophyte-dominated water columns. However, information on the responses of biofilms to submerged macrophytes and nitrogen molecules is limited. In the present study, bacterial community structure and denitrifiers were investigated in biofilms on the leaves of four submerged macrophytes and artificial plants exposed to two nitrate concentrations. The biofilm cells were evenly distributed on artificial plants but appeared in microcolonies on the surfaces of submerged macrophytes. Proteobacteria was the most abundant phylum in all samples, accounting for 27.3–64.8% of the high-quality bacterial reads, followed by Chloroflexi (3.7–25.4%), Firmicutes (3.0–20.1%), Acidobacteria (2.7–15.7%), Actinobacteria (2.2–8.7%), Bacteroidetes (0.5–9.7%), and Verrucomicrobia (2.4–5.2%). Cluster analysis showed that bacterial community structure can be significantly different on macrophytes versus from those on artificial plants. Redundancy analysis showed that electrical conductivity and nitrate concentration were positively correlated with Shannon index and operational taxonomic unit (OTU) richness (log10 transformed) but somewhat negatively correlated with microbial density. The relative abundances of five denitrifying genes were positively correlated with nitrate concentration and electrical conductivity but negatively correlated with dissolved oxygen.

  3. Fate of aniline and sulfanilic acid in UASB bioreactors under denitrifying conditions.

    Pereira, Raquel; Pereira, Luciana; van der Zee, Frank P; Madalena Alves, M

    2011-01-01

    Two upflow anaerobic sludge blanket (UASB) reactors were operated to investigate the fate of aromatic amines under denitrifying conditions. The feed consisted of synthetic wastewater containing aniline and/or sulfanilic acid and a mixture of volatile fatty acids (VFA) as the primary electron donors. Reactor 1 (R1) contained a stoichiometric concentration of nitrate and Reactor 2 (R2) a stoichiometric nitrate and nitrite mixture as terminal electron acceptors. The R1 results demonstrated that aniline could be degraded under denitrifying conditions while sulfanilic acid remains. The presence of nitrite in the influent of R2, caused a chemical reaction that led to immediate disappearance of both aromatic amines and the formation of an intense yellow coloured solution. HPLC analysis of the influent solution, revealed the emergence of three product peaks: the major one at retention time (R(t)) 14.3 min and two minor at R(t) 17.2 and 21.5 min. In the effluent, the intensity of the peaks at R(t) 14.3 and 17.2 min was very low and of that at R(t) 21.5 min increased (∼3-fold). Based on the mass spectrometry analysis, we propose the structures of some possible products, mainly azo compounds. Denitrification activity tests suggest that biomass needed to adapt to the new coloured compounds, but after a 3 days lag phase, activity is recovered and the final (N(2) + N(2)O) is even higher than that of the control.

  4. Experimental Study on Denitrification Using Coated Electrode of Immobilized Denitrifying Bacteria

    2006-01-01

    Objective To develop a coated electrode of immobilized denitrificants and to evaluate the performance of a bioelectrochemical reactor to enhance and control denitrification. Methods Denitrifying bacteria were developed by batch incubation and immobilized with polyvinyl alcohol (PVA) on the surface of activated carbon fiber (ACF) to make a coated electrode. Then the coated electrode (cathode) and graphite electrode (anode) were transferred to the reactor to reduce nitrate. Results After acclimated to the mixtrophic and autotrophic denitrification stages, the denitrifying bacteria could use hydrogen as an electron donor to reduce nitrate. When the initial nitrate concentration was 30.2 mg NO3--N/L, the denitrification efficiency was 57.3% at an applied electric current of 15 mA and a hydraulic retention time (HRT) of 12 hours.Correspondingly, the current density was 0.083 mA / cm2. The nitrate removal rate of the reactor was 34.4 g NO3--N / m3·d, and the surface area loading was 1.34 g NO3--N / m2·d. Conclusion The coated electrode may keep high quantity of biomass, thus achieving a high denitrification rate. Denitrification efficiencies are related to HRT, current density, oxidation reduction potential (ORP), dissolved oxygen (DO), pH value, and temperature.

  5. Full-scale post denitrifying biofilters: sinks of dissolved N2O?

    Bollon, Julien; Filali, Ahlem; Fayolle, Yannick; Guerin, Sabrina; Rocher, Vincent; Gillot, Sylvie

    2016-09-01

    In this study, nitrous oxide (N2O) emissions from a full-scale denitrifying biofilter plant were continuously monitored over two periods (summer campaign in September 2014 and winter campaign in February 2015). Results of the summer campaign showed that the major part (>99%) of N2O flux was found in the liquid phase and was discharged with the effluent. N2O emissions were highly variable and represented in average 1.28±1.99% and 0.22±0.31% of the nitrate uptake rate during summer and winter campaigns, respectively. Denitrification was able to consume a large amount of dissolved N2O coming from the upstream nitrification stage. In the absence of methanol injection failure and with an influent BOD/NO3-N ratio higher than 3, average reduction of N2O was estimated to be of 93%. The control of exogenous carbon dosage is essential to minimize N2O production from denitrifying biofilters, in correlation to NO2-N concentrations in the filter.

  6. Simultaneous domestic wastewater and nitrate sewage treatment by DEnitrifying AMmonium OXidation (DEAMOX) in sequencing batch reactor.

    Du, Rui; Cao, Shenbin; Li, Baikun; Wang, Shuying; Peng, Yongzhen

    2017-05-01

    A novel DEAMOX system was developed for nitrogen removal from domestic wastewater and nitrate (NO3(-)-N) sewage in sequencing batch reactor (SBR). High nitrite (NO2(-)-N) was produced from NO3(-)-N reduction in partial-denitrification process, which served as electron acceptor for anammox and was removed with ammonia (NH4(+)-N) in domestic wastewater simultaneously. A 500-days operation demonstrated that the efficient and stable nitrogen removal performance could be achieved by DEAMOX. The total nitrogen (TN) removal efficiency was as high as 95.8% with influent NH4(+)-N of 63.58 mg L(-1) and NO3(-)-N of 69.24 mg L(-1). The maximum NH4(+)-N removal efficiency reached up to 94.7%, corresponding to the NO3(-)-N removal efficiency of 97.8%. The biomass of partial-denitrification and anammox bacteria was observed to be wall-growth. The deteriorated nitrogen removal performance occurred due to excess denitrifying microbial growth in the outer layer of sludge consortium, which prevented the substrate transfer for anammox inside. However, an excellent nitrogen removal could be guaranteed by scrapping the superficial denitrifying biomass at regular intervals. Furthermore, the high-throughput sequencing analysis revealed that the Thauera genera (26.33%) was possibly responsible for the high NO2(-)-N accumulation in partial-denitrification and Candidatus Brocadia (1.7%) was the major anammox species.

  7. 反硝化除磷菌筛选及其特性研究%Studies on the screening of denitrifying and phosphorus removal bacteria and its characteristics

    安健; 伏光辉; 阮记明; 陈百尧; 龚琪本; 唐兴本; 杨先乐

    2012-01-01

    [Objective] In order to study on the characteristics of denitrifying and phosphorus removal bacteria. [Methods] Many strains with denitrification and phosphorus removal characteristics under aerobic condition were isolated by screening of microorganism and methods of biological characteristics from the water and sediment samples of shrimp culture ponds. [Results] Among them strain LY-1 could remove nitrite nitrogen from 10 mg/L to 0.04 mg/L, and the PO43- -P from 10 mg/L to 0.05 mg/L in 18 h, respectively; and approximately to 100% of denitrifying and phosphorus removal rate were reached at the DO concentration of 5.0-5.9 mg/L. Furthermore, in comparison with a denitrifying and phosphorus removal bacterium, Bacillus subtilis selected as the positive control and Escherichia coli as the negative control, strain LY-1 was tested under different pH, temperature, salty, PO43--P and nitrite concentration, its denitrifying removal rate was reached approximately 99%, and phosphorus removal rate reached 86% at the pH of 5-9; the denitrifying and phosphorus removal rate of strain YX-6 reached proximately 100% at 30 °C; The rate almost reached 99% when salty ranged between 5 and 15, phosphorus concentration was 10 mg/L and nitrite nitrogen concentration was 20 mg/L. [Conclusion] The results showed that the denitrifying and phosphorus removal of LY-1 was significantly higher than that of the two controls (P<0.05). According to the morphological, physiological and biochemical properties, and the analysis of its 16S rRNA gene sequence, strain LY-1 was identified as Bacillus cereus primarily.%[目的]研究反硝化除磷菌特性.[方法]通过微生物筛选和生物学特性研究方法,从对虾养殖池塘中筛选出多株可在有氧条件下同时具有反硝化除磷功能的菌种.[结果]菌株LY-1可在18h内将初始量为10 mg/L的亚硝酸盐氮降低至0.04 mg/L,PO43--P降低至0.05 mg/L.在DO浓度为5.0-5.9 mg/L时,该菌反硝化除磷率近100%.试验选取

  8. Development of a rapid lateral flow immunoassay test for detection of exosomes previously enriched from cell culture medium and body fluids

    Myriam Oliveira-Rodríguez

    2016-08-01

    Full Text Available Exosomes are cell-secreted nanovesicles (40–200 nm that represent a rich source of novel biomarkers in the diagnosis and prognosis of certain diseases. Despite the increasingly recognized relevance of these vesicles as biomarkers, their detection has been limited due in part to current technical challenges in the rapid isolation and analysis of exosomes. The complexity of the development of analytical platforms relies on the heterogeneous composition of the exosome membrane. One of the most attractive tests is the inmunochromatographic strips, which allow rapid detection by unskilled operators. We have successfully developed a novel lateral flow immunoassay (LFIA for the detection of exosomes based on the use of tetraspanins as targets. We have applied this platform for the detection of exosomes purified from different sources: cell culture supernatants, human plasma and urine. As proof of concept, we explored the analytical potential of this LFIA platform to accurately quantify exosomes purified from a human metastatic melanoma cell line. The one-step assay can be completed in 15 min, with a limit of detection of 8.54×105 exosomes/µL when a blend of anti-CD9 and anti-CD81 were selected as capture antibodies and anti-CD63 labelled with gold nanoparticles as detection antibody. Based on our results, this platform could be well suited to be used as a rapid exosome quantification tool, with promising diagnostic applications, bearing in mind that the detection of exosomes from different sources may require adaptation of the analytical settings to their specific composition.

  9. Does reactor staging influence microbial structure and functions in biofilm systems? The case of pre-denitrifying MBBRs

    Polesel, Fabio; Torresi, Elena; Jensen, Marlene Mark

    community based on qPCR (quantitative polymerase chain reaction) showed differences in the abundance of genes (nirS, nirK, nosZ) encoding for denitrifying enzymes in the three staged MBBRs. Further microbial characterization through 16sRNA sequencing (Illumina) is currently under investigation to determine...

  10. Using T-RFLP data on denitrifier community composition to inform understanding of denitrification in stream sediments (Invited)

    Wang, S.; Somers, K.; Sudduth, E.; Hassett, B.; Bernhardt, E. S.; Urban, D. L.

    2010-12-01

    We used terminal restriction fragment length polymorphism (T-RFLP), a molecular fingerprinting method, to characterize denitrifier communities in sediments taken from 48 study streams in North Carolina, USA. In addition to characterizing denitrifier communities, we also used denitrification enzyme activity (DEA) assays to measure potential denitrification rates. Due to differences in watershed land-use, study streams covered a gradient of nitrogen and carbon concentrations, as well as a gradient of contaminant loading from stormwater and sanitary sewers. Nitrogen and carbon (i.e., substrate) concentrations are commonly used to make predictions about denitrification rates in streams. Such models do not take into account denitrifier community composition, which may be an important, independent control of denitrification rates, particularly under stressful conditions (e.g., high contaminant loading) that prevent communities from capitalizing on high substrate availability. Our results indicate that substrate availability by itself was a weak predictor of denitrification rates; the same was also true for denitrifier community composition. However, when both factors were incorporated in a multiple regression model, the percent variation explained increased substantially. These findings suggest that T-RFLP, a relatively cost-effective method, can be used to improve our understanding of controls on denitrification rates in streams with varying watershed land-uses.

  11. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    Kester, R.A.; Boer, W. de; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of nitrous

  12. Enrichment of Breast Cancer Stem Cells by Serum-free Shaking Suspension Culture%无血清摇动悬浮培养富集乳腺癌干细胞

    闫文星; 陈玉丙; 张红梅; 国春龙; 王铁君

    2011-01-01

    Objective To investigate the characteristics of division of breast cancer MCF-7 cells under various conditions so as to develop a rapid and effective method for enrichment of breast cancer stem cells. Methods MCF-7 cells were subjected to static culture in complete medium (group A), shaking culture in complete medium (group B), static culture with cytokine (group C) and shaking culture with cytokine (group D) respectively, for 12, 24 and 36 h, then observed for division under inverted phase contrast microscope, based on which clone formation rate was calculated, and determined for the percentage of CD44+/CD24"/low lymphocyte subsets. Results In groups B and C, rod-like divisions were observed in both about 30% of cells 12 h, and in about 50% and about 60% of cells respectively 24 h, while large cell clones were formed 36 h after culture. However, in group D, rod-like division was observed in about 50% of cells 12 h, and in about 80% of cells 24 h when several cell clones appeared, while the number of cell clones decreased 36 h after culture. The percentage of CD44+/CD24"/km lymphocyte subsets 12 h after culture in group D (8. 05%) was 8 times of those in group B (0. 99%) and 2. 1 times of those in group C (3. 80%). However, the percentage 24 h after culture in group D (15. 24%) was 3 times of those in group B (4. 83%) and 6 times of those in group C (2. 30%). The percentage in group D decreased to 9. 68% 36 h after culture, which was about 9 times of those in groups B (0. 95%) and C (1. 03%). Conclusion The mitotic division of MCF-7 cells was accelerated in shaking culture with cytokine, while the percentage of CD44+/CD24'/low lymphocyte subsets increased rapidly, and stem cell pool increased significantly, indicating serum-free shaking suspension culture a rapid and effective method for enrichment of breast cancer stem cells.%目的 探讨不同培养条件下乳腺癌MCF-7细胞的分裂特点,建立快速、有效的乳腺癌干细胞富集方法.方法 将MCF-7

  13. High-efficient nitrogen removal by coupling enriched autotrophic-nitrification and aerobic-denitrification consortiums at cold temperature.

    Zou, Shiqiang; Yao, Shuo; Ni, Jinren

    2014-06-01

    This study paid particular attention to total nitrogen removal at low temperature (10°C) by excellent coupling of enriched autotrophic nitrifying and heterotrophic denitrifying consortiums at sole aerobic condition. The maximum specific nitrifying rate of the nitrifying consortium reached 8.85mgN/(gSSh). Further test in four identical lab-scale sequencing batch reactors demonstrated its excellent performance for bioaugmentation in potential applications. On the other hand, the aerobic denitrifying consortium could achieve a specific denitrifying rate of 32.93mgN/(gSSh) under dissolved oxygen of 1.0-1.5mg/L at 10°C. Coupling both kinds of consortiums was proved very successful for a perfect total nitrogen (TN) removal at COD/N of 4 and dissolved oxygen of 1.5-4.5mg/L, which was hardly reached by any single consortium reported previously. The encouraging results from coupling aerobic consortiums implied a huge potential in practical treatment of low-strength domestic wastewater (200-300mg/L COD) during wintertime.

  14. 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

    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)

  15. Nitrate removal by nitrate-dependent Fe(II) oxidation in an upflow denitrifying biofilm reactor.

    Zhou, Jun; Wang, Hongyu; Yang, Kai; Sun, Yuchong; Tian, Jun

    2015-01-01

    A continuous upflow biofilm reactor packed with ceramsite was constructed for nitrate removal under an anaerobic atmosphere without an organic carbon source. Denitrifying bacteria, Pseudomonas sp. W1, Pseudomonas sp. W2 and Microbacterium sp. W5, were added to the bioreactor as inocula. Nitrate concentration, nitrite accumulation and nitrogen removal efficiency in the effluent were investigated under various conditions set by several parameters including pH, hydraulic retention time (HRT), ratios of carbon to nitrogen (C/N) and temperature. The results illustrated that the maximum removal efficiency of nitrogen was 85.39%, under optimum reaction parameters, approximately pH 6.5-7, HRT = 48 hours and C/N = 13.1:1 at temperature of 30 °C, which were determined by experiment.

  16. Enhanced Performance of Denitrifying Sulifde Removal Process by 1,2-Naphthoquinone-4-Sulphonate

    Liu Chunshuang; Han Kang; Zhao Dongfeng; Guo Yadonag; Liu Lihong; Liu Fang; Zhao Chaocheng

    2016-01-01

    The denitrifying sulifde removal (DSR) process with bio-granules comprising both heterotrophic and autotrophic denitriifers can simultaneously convert nitrate, sulifde and acetate species into di-nitrogen gas, elemental sulfur and carbon dioxide, respectively, at high loading rates. This study has determined that the reaction rate of sulifde oxidized into sulfur could be enhanced in the presence of 1,2-naphthoquinone-4-sulphonate (NQS). The presence of NQS mitigated the inhibi-tion effects of sulifde species on denitriifcation. Furthermore, the reaction rates of nitrate and acetate to nitrogen gas and CO2, respectively, were also promoted in the presence of NQS, thereby enhancing the performance of DSR granules. The advantages and disadvantages of applying the NQS-DSR process are discussed.

  17. Continuous treatment of azo acid dyes by photo-dependent denitrifying sludge

    2002-01-01

    Simultaneous removals of dye and nitrate by photo-dependent denitrifying sludge(PDDS) have been demonstrated in a continuousflow bench-scale reactor.The best C/N for the degradation of azo dyes by PDDS was 1.5.The specific removal rate of azo dye AB92 decreased with a decrease in hydraulic retention time and increased with a decrease in solids retention time.The degradation rate of TOC decreased with a decrease in hydraulic retention time.AB92,which has nitro and hydroxyl substitutions in non-para positions,was uniquely degraded.During continuous flow treatment experiments using PDDS,complete degradation of azo dyes AB92 and AO20 at influent concentrations of 40 mg/L and 30 mg/L,respectively,was achieved with an HRT of 16.

  18. Heterotrophic ammonium removal characteristics of an aerobic heterotrophic nitrifying-denitrifying bacterium, Providencia rettgeri YL

    TAYLOR Shauna M; HE Yiliang; ZHAO Bin; HUANG Jue

    2009-01-01

    Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium (NH4+-N). In order to further analyze its removal ability, several experiments were conducted to identify the growth and ammonium removal response in different carbon to nitrogen (C/N) mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions (C/N 10, 30℃, 120 r/min), YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth. The nitrification products hydroxylamine (NH2OH), nitrite (NO2-) and nitrate (NO3-) as well as the denitrification product, nitrogen gas (N2), were detected under completely aerobic conditions.

  19. Optimization of hard clams, polychaetes, physical disturbance and denitrifying bacteria of removing nutrients in marine sediment.

    Shen, Hui; Thrush, Simon F; Wan, Xihe; Li, Hui; Qiao, Yi; Jiang, Ge; Sun, Ruijian; Wang, LiBao; He, Peimin

    2016-09-15

    Marine organisms are known to play important roles in transforming nutrients in sediments, however, guidelines to optimize sediment restoration are not available. We conducted a laboratory mesocosm experiment to investigate the role of hard clams, polychaetes, the degree of physical disturbance and denitrifying bacterial concentrations in removing total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) in marine sediments. Response surface methodology was employed to analyze the results of initial experiments and in a subsequent experiment identified optimal combinations of parameters. Balancing the TN, TP, TOC removal efficiency, our model predicted 39% TN removal, 33% TP removal, and 42% TOC removal for a 14-day laboratory bioremediation trial using hard clams biomass of 1.2kgm(-2), physical disturbance depth of 16.4cm, bacterial density of 0.18Lm(-2), and polychaetes biomass of 0.16kgm(-2), respectively. These results emphasize the value of combining different species in field-based bioremediation.

  20. Maintaining granulation in a denitrifying upflow sludge-blanket reactor treating groundwater with low hardness.

    Rouse, Joseph D; Nakashima, Takahiro; Furukawa, Kenji

    2003-01-01

    Maintenance of denitrifying granular sludge for treating soft groundwater (total hardness = 75 mg calcium carbonate/L) in an upflow sludge-blanket reactor was demonstrated with complete removal of applied nitrate (20 mg N/L) over extended operation and a hydraulic residence time of 34 minutes. A high pH of approximately 9.0 was shown to be important for generation of mineral precipitation needed for production of heavy granular sludge with good retention characteristics. As a method of increasing precipitation potential, pH adjustment was determined to be more economically favorable than calcium or alkalinity supplementation. In addition, temporary increases in substrate loading were shown to be effective for enhancing biomass levels in a manageable granular sludge. The significance of biomass in promoting mineral precipitation was discussed.

  1. Soil functional operating range linked to microbial biodiversity and community composition using denitrifiers as model guild.

    Sara Hallin

    Full Text Available Soil microorganisms are key players in biogeochemical cycles. Yet, there is no consistent view on the significance of microbial biodiversity for soil ecosystem functioning. According to the insurance hypothesis, declines in ecosystem functioning due to reduced biodiversity are more likely to occur under fluctuating, extreme or rapidly changing environmental conditions. Here, we compare the functional operating range, a new concept defined as the complete range of environmental conditions under which soil microbial communities are able to maintain their functions, between four naturally assembled soil communities from a long-term fertilization experiment. A functional trait approach was adopted with denitrifiers involved in nitrogen cycling as our model soil community. Using short-term temperature and salt gradients, we show that the functional operating range was broader and process rates were higher when the soil community was phylogenetically more diverse. However, key bacterial genotypes played an important role for maintaining denitrification as an ecosystem functioning under certain conditions.

  2. DRIVERS OF THE DYNAMICS OF DIAZOTROPHS AND DENITRIFIERS IN NORTH SEA BOTTOM WATERS AND SEDIMENTS

    Lucas eStal

    2015-07-01

    Full Text Available The fixation of dinitrogen (N2 and denitrification are two opposite processes in the nitrogen cycle. The former transfers atmospheric dinitrogen gas into bound nitrogen in the biosphere, while the latter returns this bound nitrogen back to atmospheric dinitrogen. It is unclear whether or not these processes are intimately connected in any microbial ecosystem or that they are spatially and/or temporally separated. Here, we measured seafloor nitrogen fixation and denitrification as well as pelagic nitrogen fixation by using the stable isotope technique. Alongside, we measured the diversity, abundance, and activity of nitrogen-fixing and denitrifying microorganisms at three stations in the southern North Sea. Nitrogen fixation ranged from undetectable to 2.4 nmol N L-1 d-1 and from undetectable to 8.2 nmol N g-1 d-1 in the water column and seafloor, respectively. The highest rates were measured in August at Doggersbank, both for the water column and for the seafloor. Denitrification ranged from 1.7 to 208.8 µmol m-2 d-1 and the highest rates were measured in May at the Oyster Grounds. DNA sequence analysis showed sequences of nifH, a structural gene for nitrogenase, related to sequences from anaerobic sulfur/iron reducers and sulfate reducers. Sequences of the structural gene for nitrite reductase, nirS, were related to environmental clones from marine sediments. Quantitative polymerase chain reaction (qPCR data revealed the highest abundance of nifH and nirS genes at the Oyster Grounds. Quantitative reverse transcription polymerase chain reaction (qRT-PCR data revealed the highest nifH expression at Doggersbank and the highest nirS expression at the Oyster Grounds. The distribution of the diazotrophic and denitrifying communities seems to be subject to different selecting factors, leading to spatial and temporal separation of nitrogen fixation and denitrification. These selecting factors include temperature, organic matter availability, and

  3. Responses of activities, abundances and community structures of soil denitrifiers to short-term mercury stress

    Zhifeng Zhou; Yuanming Zheng; Jupei Shen; Limei Zhang; Yurong Liu; Jizheng He

    2012-01-01

    The responses of activities,abundances and community structures of soil denitrifiers to mercury(Hg)stress were investigated through a short-term incubation experiment.Four soil treatments with different concentrations of Hg(CK,Hg25,Hg50,and Hgl00,denoted as 0,25,50,and 100 mg Hg/kg dry soil,respectively)were incubated for 28 days.Soil denitrification enzyme activity(DEA)was measured at day 3,7 and 28.The abundances and community structures of two denitrification concerning genes,nirS(Cd1-nitrite reductase gene)and nosZ(nitrous oxide reductase gene),were analyzed using real-time PCR and denaturing gradient gel electrophoresis(DGGE).Results showed that soil DEA was significantly stimulated in the treatments of Hg25 and Hg50 compared with others at day 7.Meanwhile,no difference in the abundances of soil nirS and nosZ was found between Hg spiked treatments and CK,except the lower abundance of nirS(P < 0.05)in the Hg added treatments compared with that in the CK at day 28.The community structures of denitrifiers based on nirS gene presented obvious change at day 7 along with the Hg additions,however,no variation was found in all treatments based on the nosZ gene.The results indicated that Hg(Hg25 and Hg50)had a strongly short-term stimulation on soil DEA,and nirS gene is more sensitive than nosZ gene to Hg stress.

  4. Denitrifying bacterial communities affect current production and nitrous oxide accumulation in a microbial fuel cell.

    Ariadna Vilar-Sanz

    Full Text Available The biocathodic reduction of nitrate in Microbial Fuel Cells (MFCs is an alternative to remove nitrogen in low carbon to nitrogen wastewater and relies entirely on microbial activity. In this paper the community composition of denitrifiers in the cathode of a MFC is analysed in relation to added electron acceptors (nitrate and nitrite and organic matter in the cathode. Nitrate reducers and nitrite reducers were highly affected by the operational conditions and displayed high diversity. The number of retrieved species-level Operational Taxonomic Units (OTUs for narG, napA, nirS and nirK genes was 11, 10, 31 and 22, respectively. In contrast, nitrous oxide reducers remained virtually unchanged at all conditions. About 90% of the retrieved nosZ sequences grouped in a single OTU with a high similarity with Oligotropha carboxidovorans nosZ gene. nirS-containing denitrifiers were dominant at all conditions and accounted for a significant amount of the total bacterial density. Current production decreased from 15.0 A · m(-3 NCC (Net Cathodic Compartment, when nitrate was used as an electron acceptor, to 14.1 A · m(-3 NCC in the case of nitrite. Contrarily, nitrous oxide (N2O accumulation in the MFC was higher when nitrite was used as the main electron acceptor and accounted for 70% of gaseous nitrogen. Relative abundance of nitrite to nitrous oxide reducers, calculated as (qnirS+qnirK/qnosZ, correlated positively with N2O emissions. Collectively, data indicate that bacteria catalysing the initial denitrification steps in a MFC are highly influenced by main electron acceptors and have a major influence on current production and N2O accumulation.

  5. Modeling of Cr(VI) Bioreduction Under Fermentative and Denitrifying Conditions

    Molins, S.; Steefel, C.; Yang, L.; Beller, H. R.

    2011-12-01

    The mechanisms of bioreductive immobilization of Cr(VI) were investigated by reactive transport modeling of a set of flow-through column experiments performed using natural Hanford 100H aquifer sediment. The columns were continuously eluted with 5 μM Cr(VI), 5 mM lactate as the electron donor, and selected electron acceptors (tested individually). Here we focus on the two separate experimental conditions that showed the most removal of Cr(VI) from solution: fermentation and denitrification. In each case, a network of enzymatic and abiotic reaction pathways was considered to interpret the rate of chromate reduction. The model included biomass growth and decay, and thermodynamic limitations on reaction rates, and was constrained by effluent concentrations measured by IC and ICP-MS and additional information from bacterial isolates from column effluent. Under denitrifying conditions, Cr(VI) reduction was modeled as co-metabolic with nitrate reduction based on experimental observations and previous studies on a denitrifying bacterium derived from the Hanford 100H aquifer. The reactive transport model results supported this interpretation of the reaction mechanism and were used to quantify the efficiency of the process. The models results also suggest that biomass growth likely relied on a nitrogen source other than ammonium (e.g. nitrate). Under fermentative conditions and based on cell suspension studies performed on a bacterial isolate from the columns, the model assumes that Cr(VI) reduction is carried out directly by fermentative bacteria that convert lactate into acetate and propionate. The evolution to complete lactate fermentation and Cr(VI) reduction took place over a week's time and simulations were used to determine an estimate for a lower limit of the rate of chromate reduction by calibration with the flow-through column experimental results. In spite of sulfate being added to these columns, sulfate reduction proceeded at a slow rate and was not well

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

    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.

  7. Performance of Denitrifying Bioreactors at Reducing  Agricultural Nitrogen Pollution in a Humid  Subtropical Coastal Plain Climate

    Timothy Rosen

    2017-02-01

    Full Text Available Denitrifying bioreactors are an agricultural best management practice developed in the  midwestern United States to treat agricultural drainage water enriched with nitrate‐nitrogen (NO3N. The practice is spreading rapidly to agricultural regions with poor water quality due to nutrient  enrichment. This makes it imperative to track bioreactor NO3‐N reduction efficiency as this practice  gets deployed to new regions. This study evaluated the application and performance of denitrifying  bioreactors in the humid subtropical coastal plain environment of the Chesapeake Bay catchment to  provide data about regionally specific NO3‐N reduction efficiencies. NO3‐N samples were taken  before  and  after  treatment  at  three  denitrifying  bioreactors,  in  addition  to  other  nutrients  (orthophosphate‐phosphorus,  PO4‐P;  ammonium‐nitrogen,  NH4‐N;  total  nitrogen,  TN;  total  phosphorus,  TP  and  water  quality  parameters  (dissolved  oxygen,  DO;  oxidation  reduction  potential,  ORP;  pH;  specific  conductance,  SPC.  Total  removal  ranged  drastically  between  bioreactors from 10 to 133 kg N, with removal efficiencies of 9.0% to 62% and N removal rates of  0.21 to 5.36 g N removed per m3 of bioreactor per day. As the first bioreactor study in the humid  subtropical coastal plain, this data provides positive proof of concept that denitrifying bioreactor is  another tool for reducing N loads in agricultural tile drainage in this region.

  8. 应用渗透膜高密度培养富硒螺旋藻%Application of Osmotic Membrane for High Cell Density Culture of Selenium-Enriched Spirulina platensis

    任璐艳; 靳兴媛; 周永林; 张逸波; 凌钦婕; 黄峙

    2012-01-01

    应用透析袋(OT法)组装光生物反应器,与鼓泡式生物反应器(AB法)和摇瓶(SB法)进行对比实验,探讨利用渗透膜建立高密度培养富硒螺旋藻(Se-sP)方法的可行性。称质量法监测并推算藻细胞生长率和最大生物量,荧光光度法测定se-sP及其培养液中硒含量和形态变化,分光光度法检测Se-SP中总蛋白(TP)、藻蓝蛋白(PC)、叶绿素a(Chla)、总胡萝卜素(Caro)、水溶性多糖(SPS)及巯基(-SH)含量等主要营养构成,培养液中无机碳(IC)和有机溶解碳(DOC)的含量采用自动分析仪测定。结果发现:OT法培养Se-SP的最大生物量可达9.6·g/L,是AB和SB方法培养的3-5倍,其中有机硒转化率及TP、PC、Chla、SPS和-SH等主要营养成分的含量均有明显提高。相应地,培养基中IC剩余减少,DOC无明显累积。结果提示,OT法可实现Se-SP高密度培养,并有望获得优质Se-SP产品,其优势体现在高细胞增殖速率、高有机硒转化率、高无机营养源消耗率和低有机碳的积累,便于培养液的再生利用,减少废液污染。%Selenium-enriched Spirulinaplatensis (Se-SP) was cultured in osmotic membrane tube (OT) and compared with air blowing bioreactor (AB) and shaking bottle (SB) cultures under the same conditions. Se supplementation was 100 μ g/mL in the form of sodium selenite. Growth rate and maximum biomass were monitored and deduced according to dry weight at designated time points. Total Se, organic Se and inorganic Se in Se-SP as well as soluble and insoluble Se species in culture medium were determined using a fluorimeter. Total protein (TP), phycocyanin (PC), chlorophyll a (Chla), carotenoids (Caro), total polysac- charides (SPS) and sulfydryl groups (-SH) in Se-SP were also detected colorimetrically. The contents of inorganic carbon (IC) and dissolved organic carbon

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

    Krieger, Bärbel; Schwermer, Carsten U.; Rezakhani, Nastaran;

    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...... 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...

  10. The Denitrifying Biological Phosphorus Removal Performance in Anaerobic/Anoxic Sequencing Batch Reactor: The Effect of Carbon Source

    Gürtekin, Engin; ŞEKERDAĞ, Nusret

    2015-01-01

    In this study, the effect of carbon source on denitrifying biological phosphorus removal performance in acetate and glucose fed two anaerobic/anoxic sequencinq batch reactor (SBR) was investigated. Glucose and acetate were used as the substrates. In acetate and glucose fed reactors, the COD (Chemical Oxygen Demand) removal efficiencies were 91,90% and PO4-P removal efficiencies were 87,51% respectively. These results shows that the phosphorus removal efficiency is lower in glucose fed reactor.

  11. Simultaneous pollutant removal and electricity generation in denitrifying microbial fuel cell with boric acid-borate buffer solution.

    Chen, Gang; Zhang, Shaohui; Li, Meng; Wei, Yan

    2015-01-01

    A double-chamber denitrifying microbial fuel cell (MFC), using boric acid-borate buffer solution as an alternative to phosphate buffer solution, was set up to investigate the influence of buffer solution concentration, temperature and external resistance on electricity generation and pollutant removal efficiency. The result revealed that the denitrifying MFC with boric acid-borate buffer solution was successfully started up in 51 days, with a stable cell voltage of 205.1 ± 1.96 mV at an external resistance of 50 Ω. Higher concentration of buffer solution favored nitrogen removal and electricity generation. The maximum power density of 8.27 W/m(3) net cathodic chamber was obtained at a buffer solution concentration of 100 mmol/L. An increase in temperature benefitted electricity generation and nitrogen removal. A suitable temperature for this denitrifying MFC was suggested to be 25 °C. Decreasing the external resistance favored nitrogen removal and organic matter consumption by exoelectrogens.

  12. The incidence of nirS and nirK and their genetic heterogeneity in cultivated denitrifiers.

    Heylen, Kim; Gevers, Dirk; Vanparys, Bram; Wittebolle, Lieven; Geets, Joke; Boon, Nico; De Vos, Paul

    2006-11-01

    Gene sequence analysis of nirS and nirK, both encoding nitrite reductases, was performed on cultivated denitrifiers to assess their incidence in different bacterial taxa and their taxonomical value. Almost half of the 227 investigated denitrifying strains did not render an nir amplicon with any of five previously described primers. NirK and nirS were found to be prevalent in Alphaproteobacteria and Betaproteobacteria, respectively, nirK was detected in the Firmicutes and Bacteroidetes and nirS and nirK with equal frequency in the Gammaproteobacteria. These observations deviated from the hitherto reported incidence of nir genes in bacterial taxa. NirS gene phylogeny was congruent with the 16S rRNA gene phylogeny on family or genus level, although some strains did group within clusters of other bacterial classes. Phylogenetic nirK gene sequence analysis was incongruent with the 16S rRNA gene phylogeny. NirK sequences were also found to be significantly more similar to nirK sequences from the same habitat than to nirK sequences retrieved from highly related taxa. This study supports the hypothesis that horizontal gene transfer events of denitrification genes have occurred and underlines that denitrification genes should not be linked with organism diversity of denitrifiers in cultivation-independent studies.

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

    Michela eLangone

    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 α –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

  14. Characteristics of a Novel Aerobic Denitrifying Bacterium, Enterobacter cloacae Strain HNR.

    Guo, Long-Jie; Zhao, Bin; An, Qiang; Tian, Meng

    2016-03-01

    A novel aerobic denitrifier strain HNR, isolated from activated sludge, was identified as Enterobacter cloacae by16S rRNA sequencing analysis. Glucose was considered as the most favorable C-source for strain HNR. The logistic equation well described the bacterial growth, yielding a maximum growth rate (μmax) of 0.283 h(-1) with an initial NO3 (-)-N concentration of 110 mg/L. Almost all NO3 (-)-N was removed aerobically within 30 h with an average removal rate of 4.58 mg N L(-1) h(-1). Nitrogen balance analysis revealed that proximately 70.8 % of NO3 (-)-N was removed as gas products and only 20.7 % was transformed into biomass. GC-MS result indicates that N2 was the end product of aerobic denitrification. The enzyme activities of nitrate reductase and nitrite reductase, which are related to the process of aerobic denitrification, were 0.0688 and 0.0054 U/mg protein, respectively. Thus, the aerobic denitrification of reducing NO3 (-) to N2 by strain HNR was demonstrated. The optimal conditions for nitrate removal were C/N ratio 13, pH value 8, shaking speed 127 rpm and temperature 30 °C. These findings show that E. cloacae strain HNR has a potential application on wastewater treatment to achieve nitrate removal under aerobic conditions.

  15. Microbial Characterization of Denitrifying Sulifde Removal Sludge Using High-Throughput Amplicon Sequencing Method

    Ma Wenjuan; Liu Chunshuang; Zhao Dongfeng; Guo Yadong; Wang Aijie; Jia Kuili

    2015-01-01

    The denitrifying sulifde removal (DSR) process has recently been studied extensively from an engineering per-spective. However, the importance of microbial communities of this process was generally underestimated. In this study, the microbial community structure of a lab-scale DSR reactor was characterized in order to provide a comprehensive insight into the key microbial groups in DSR system. Results from high-throughput sequencing analysis revealed that the frac-tion of autotrophic denitriifers increased from 2.34 % to 10.93% and 44.51% in the DSR system when the inlfuent NaCl increased from 0 g/L, to 4 g/L and 30 g/L, respectively. On the contrary, the fraction of heterotrophic denitriifers decreased from 61.74% to 39.57%, and 24.12%, respectively.Azoarcus andThiobacillus were the main autotrophic denitriifers, and Thauera was the main hetetrophic denitriifer during the whole process. This study could be useful for better understanding the interaction between autotrophs and heterotrophs in DSR system.

  16. Formaldehyde and urea removal in a denitrifying granular sludge blanket reactor.

    Eiroa, M; Kennes, C; Veiga, M C

    2004-09-01

    Simultaneous formaldehyde biodegradation, urea hydrolysis and denitrification in anoxic batch assays and in a continuous laboratory anoxic reactor were investigated. In batch assays, the initial formaldehyde biodegradation rate was around 0.7 g CH(2)Og VSS(-1)d(-1) and independent of the urea concentration (90- 370 mg N-NH(2)CONH(2)l(-1)). Urea was completely hydrolyzed to ammonium in the presence of 430 mg l(-1) formaldehyde and complete denitrification took place in all cases (125 mg N-NO(-)(3)l(-1)). Formaldehyde removal efficiencies above 99.5% were obtained in a lab-scale denitrifying upflow sludge blanket reactor at organic loading rates between 0.37 and 2.96 kg CODm(-3)d(-1) (625-5000 mg CH(2)Ol(-1)). The urea loading rate was increased from 0.06 to 0.44 kg Nm(-3)d(-1) (100-800 mg N-NH(2)CONH(2)l(-1)) and hydrolysis to ammonium was around 77.5% at all loading rates. The denitrification process was always almost complete (100-800 mg N-NO(3)(-)l(-1)), due to the high COD/N ratio of 6.7 in the influent. A minimum value of 3.5 was found to be required for full denitrification. The composition of the biogas indicated that denitrification and methanogenesis occurred simultaneously in the same unit. A good granulation of the sludge was observed.

  17. Correlating denitrifying catabolic genes with N2O and N2 emissions from swine slurry composting.

    Angnes, G; Nicoloso, R S; da Silva, M L B; de Oliveira, P A V; Higarashi, M M; Mezzari, M P; Miller, P R M

    2013-07-01

    This work evaluated N dynamics that occurs over time within swine slurry composting piles. Real-time quantitative PCR (qPCR) analyzes were conducted to estimate concentrations of bacteria community harboring specific catabolic nitrifying-ammonium monooxygenase (amoA), and denitrifying nitrate- (narG), nitrite- (nirS and nirG), nitric oxide- (norB) and nitrous oxide reductases (nosZ) genes. NH3-N, N2O-N, N2-N emissions represented 15.4 ± 1.9%, 5.4 ± 0.9%, and 79.1 ± 2.0% of the total nitrogen losses, respectively. Among the genes tested, temporal distribution of narG, nirS, and nosZ concentration correlated significantly (pcompost pile. Considering our current empirical limitations to accurately measure N2 emissions from swine slurry composting at field scale the use of these catabolic genes could represent a promising monitoring tool to aid minimize our uncertainties on biological N mass balances in these systems.

  18. A biofilm model to understand the onset of sulfate reduction in denitrifying membrane biofilm reactors.

    Tang, Youneng; Ontiveros-Valencia, Aura; Feng, Liang; Zhou, Chen; Krajmalnik-Brown, Rosa; Rittmann, Bruce E

    2013-03-01

    This work presents a multispecies biofilm model that describes the co-existence of nitrate- and sulfate-reducing bacteria in the H(2)-based membrane biofilm reactor (MBfR). The new model adapts the framework of a biofilm model for simultaneous nitrate and perchlorate removal by considering the unique metabolic and physiological characteristics of autotrophic sulfate-reducing bacteria that use H(2) as their electron donor. To evaluate the model, the simulated effluent H(2), UAP (substrate-utilization-associated products), and BAP (biomass-associated products) concentrations are compared to experimental results, and the simulated biomass distributions are compared to real-time quantitative polymerase chain reaction (qPCR) data in the experiments for parameter optimization. Model outputs and experimental results match for all major trends and explain when sulfate reduction does or does not occur in parallel with denitrification. The onset of sulfate reduction occurs only when the nitrate concentration at the fiber's outer surface is low enough so that the growth rate of the denitrifying bacteria is equal to that of the sulfate-reducing bacteria. An example shows how to use the model to design an MBfR that achieves satisfactory nitrate reduction, but suppresses sulfate reduction.

  19. Simultaneous Nitrogen and Phosphorus Removal by Denitrifying Dephosphatation in a (AO)2 Sequencing Batch Reactor

    ZHANG Yan-ping; PENG Yong-zhen; WANG Shu-ying; WANG Shao-po

    2005-01-01

    A 24 L working volume reactor was used for the research on simultaneous phosphorus (P) and nitrogen (N) removal by denitrifying dephosphatation in an anaerobic-oxid-anoxic-oxid sequencing batch reactor ((AO)2SBR) system. The durations of each phase are: anaerobic 1.5 h, aerobic 2.5 h, anoxic 1.5 h, post-aerobic 0.5 h, settling 1.0 h, fill 0.5 h. The successful removal of nitrogen and phosphorus is achieved in a stable (AO)2SBR. The effluent P concentrations is below 1 mg/L, and the COD,TN and P average removal efficiency is 88.9%, 77.5% and 88.7%, respectively. The batch experiment results show that the durations of aerobic and anoxic phase influence the P removal efficiency. Some feature points are found on the DO, ORP and pH curves to demonstrate the complete of phosphate release and phosphate uptake. These feature points can be used for the control of (AO)2 SBR.

  20. Microbial community analysis of an aerobic nitrifying-denitrifying MBR treating ABS resin wastewater.

    Chang, Chia-Yuan; Tanong, Kulchaya; Xu, Jia; Shon, Hokyong

    2011-05-01

    A two-stage aerobic membrane bioreactor (MBR) system for treating acrylonitrile butadiene styrene (ABS) resin wastewater was carried out in this study to evaluate the system performance on nitrification. The results showed that nitrification of the aerobic MBR system was significant and the highest TKN removal of approximately 90% was obtained at hydraulic retention time (HRT) 18 h. In addition, the result of nitrogen mass balance revealed that the percentage of TN removal due to denitrification was in the range of 8.7-19.8%. Microbial community analysis based on 16s rDNA molecular approach indicated that the dominant ammonia oxidizing bacteria (AOB) group in the system was a β-class ammonia oxidizer which was identified as uncultured sludge bacterium (AF234732). A heterotrophic aerobic denitrifier identified as Thauera mechernichensis was found in the system. The results indicated that a sole aerobic MBR system for simultaneous removals of carbon and nitrogen can be designed and operated for neglect with an anaerobic unit.

  1. 水培条件下几种观赏植物对铅的富集特征%Enrichment Characteristics of Pb by Several Kinds of Ornamental Plants Under Hydroponic Culture

    李翠兰; 邵泽强; 王玉军; 张晋京

    2011-01-01

    通过水培试验,研究了铅处理质量浓度为0~200 mg·L-1条件下,7种观赏植物(包括四季海棠、百日草、茶花凤仙、金鱼草、金盏菊、天竺葵和雁来红)的生长反应和富集特征.结果表明:供试观赏植物在试验的铅胁迫水平下都具有较强的耐性;四季海棠和百日草的地上部最大铅质量分数分别达到了1 229.2、1 209.7 mg·kg-1,满足超富集植物的临界质量分数标准,同时它们在试验铅处理质量浓度下的地上部铅质量分数和富集系数均显著高于其他观赏植物;四季海棠和百日草的铅转移系数最高值可达到0.9以上,并且百日草铅质量浓度在200 mg·L-1时的转移系数仍高于100 mg·L-1时的转移系数.%The growth response and enrichment characteristics of seven ornamental plants, Begonia semperflorens, Zinnia elegan, Impatiens balsamina, Antirrhinum majus, Calendula officinalis, Pelargonium hortorum and Amaranthus tricolo, were studied under hydroponic culture with 0-200 mg · L-1 of Pb. Results showed that all the tested ornamental plants had higher tolerance to Pb in the range of experimental Pb stress levels. The highest Pb mass fractions in the above-ground parts of B. semperflorens and Z. elegan were 1 229.2 and 1 209.7 mg · kg-1, respectively, which reached the critical standard of Pb hyperaccumulating plants. And the Pb mass fraction and bioaccumulation coefficient in the above-ground parts of B. semperflorens and Z. elegan was significantly higher than those of the other five ornamental plants. The highest Pb translocation factors for B. semperflorens and Z. elegan were over 0.9, and the Pb translocation factor for Z. elegan was still higher under 200 mg · L-1 than under 100 mg · L-1 of Pb.

  2. Uranium Conversion & Enrichment

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-06

    The isotopes of uranium that are found in nature, and hence in ‘fresh’ Yellowcake’, are not in relative proportions that are suitable for power or weapons applications. The goal of conversion then is to transform the U3O8 yellowcake into UF6. Conversion and enrichment of uranium is usually required to obtain material with enough 235U to be usable as fuel in a reactor or weapon. The cost, size, and complexity of practical conversion and enrichment facilities aid in nonproliferation by design.

  3. A Cultural Classroom Library

    Lawrence, Maria

    2007-01-01

    Native American and other cultural stories provide students with a broader perspective on the world. In addition, cultural stories connect science content and knowledge about the world to cultural interpretations and people's life ways. By implementing the ideas suggested in this article, you can select books that both enrich your science library…

  4. Tertiary Denitrification of the Secondary Effluent by Denitrifying Biofilters Packed with Different Sizes of Quartz Sand

    Nan Wei

    2014-05-01

    Full Text Available Tertiary denitrification of the secondary effluent in wastewater treatment plants is necessary to control the eutrophication of receiving water bodies. Two denitrifying biofilters (DNBF, one packed with quart sand with sizes of 2–4 mm (DNBFS and the other of 4–6 mm (DNBFL, were operated for tertiary denitrification under empty bed retention times (EBRTs of 30 min, 15 min and 7.5 min, respectively. Under EBRTs of 30 min, 15 min and 7.5 min, the NO3−-N removal percentages were 93%, 82% and 83% in DNBFS, and were 92%, 68% and 36% in DNBFL, respectively. The nitrogen removal loading rates increased with decreasing EBRTs, and at the EBRT of 7.5 min, the rate was 2.15 kg/(m3·d in DNBFS and 1.08 kg/(m3·d in DNBFL. The half-order denitrification coefficient of DNBFS increased from 0.42 (mg/L1/2/min at the EBRT of 30 min to 0.70 (mg/L1/2/min at the EBRT of 7.5 min, while did not vary much in DNBFL with values from 0.22 to 0.25 (mg/L1/2/min. The performance of both DNBFs was stable within each backwashing cycle, with the NO3−-N removal percentage variation within 5%. Better denitrification was achieved in DNBFS but with a slightly high decreased flow rate during the operation.

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

    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.

  6. Ecology of Nitrogen Fixing, Nitrifying, and Denitrifying Microorganisms in Tropical Forest Soils

    Pajares, Silvia; Bohannan, Brendan J. M.

    2016-01-01

    Soil microorganisms play important roles in nitrogen cycling within forest ecosystems. Current research has revealed that a wider variety of microorganisms, with unexpected diversity in their functions and phylogenies, are involved in the nitrogen cycle than previously thought, including nitrogen-fixing bacteria, ammonia-oxidizing bacteria and archaea, heterotrophic nitrifying microorganisms, and anammox bacteria, as well as denitrifying bacteria, archaea, and fungi. However, the vast majority of this research has been focused in temperate regions, and relatively little is known regarding the ecology of nitrogen-cycling microorganisms within tropical and subtropical ecosystems. Tropical forests are characterized by relatively high precipitation, low annual temperature fluctuation, high heterogeneity in plant diversity, large amounts of plant litter, and unique soil chemistry. For these reasons, regulation of the nitrogen cycle in tropical forests may be very different from that of temperate ecosystems. This is of great importance because of growing concerns regarding the effect of land use change and chronic-elevated nitrogen deposition on nitrogen-cycling processes in tropical forests. In the context of global change, it is crucial to understand how environmental factors and land use changes in tropical ecosystems influence the composition, abundance and activity of key players in the nitrogen cycle. In this review, we synthesize the limited currently available information regarding the microbial communities involved in nitrogen fixation, nitrification and denitrification, to provide deeper insight into the mechanisms regulating nitrogen cycling in tropical forest ecosystems. We also highlight the large gaps in our understanding of microbially mediated nitrogen processes in tropical forest soils and identify important areas for future research. PMID:27468277

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

    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.

  8. Enriching the Catalog

    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…

  9. Abundance, composition and activity of ammonia oxidizer and denitrifier communities in metal polluted rice paddies from South China.

    Yuan Liu

    Full Text Available While microbial nitrogen transformations in soils had been known to be affected by heavy metal pollution, changes in abundance and community structure of the mediating microbial populations had been not yet well characterized in polluted rice soils. Here, by using the prevailing molecular fingerprinting and enzyme activity assays and comparisons to adjacent non-polluted soils, we examined changes in the abundance and activity of ammonia oxidizing and denitrifying communities of rice paddies in two sites with different metal accumulation situation under long-term pollution from metal mining and smelter activities. Potential nitrifying activity was significantly reduced in polluted paddies in both sites while potential denitrifying activity reduced only in the soils with high Cu accumulation up to 1300 mg kg-1. Copy numbers of amoA (AOA and AOB genes were lower in both polluted paddies, following the trend with the enzyme assays, whereas that of nirK was not significantly affected. Analysis of the DGGE profiles revealed a shift in the community structure of AOA, and to a lesser extent, differences in the community structure of AOB and denitrifier between soils from the two sites with different pollution intensity and metal composition. All of the retrieved AOB sequences belonged to the genus Nitrosospira, among which species Cluster 4 appeared more sensitive to metal pollution. In contrast, nirK genes were widely distributed among different bacterial genera that were represented differentially between the polluted and unpolluted paddies. This could suggest either a possible non-specific target of the primers conventionally used in soil study or complex interactions between soil properties and metal contents on the observed community and activity changes, and thus on the N transformation in the polluted rice soils.

  10. Bacterial community succession during the enrichment of chemolithoautotrophic arsenite oxidizing bacteria at high arsenic concentrations

    Nguyen Ai Le; Akiko Sato; Daisuke Inoue; Kazunari Sei; Satoshi Soda; Michihiko Ike

    2012-01-01

    To generate cost-effective technologies for the removal of arsenic from water,we developed an enrichment culture of chemolithoautotrophic arsenite oxidizing bacteria (CAOs) that could effectively oxidize widely ranging concentrations of As(Ⅲ) to As(Ⅴ).In addition,we attempted to elucidate the enrichment process and characterize the microbial composition of the enrichment culture.A CAOs enrichment culture capable of stably oxidizing As(Ⅲ) to As(Ⅴ) was successfully constructed through repeated batch cultivation for more than 700 days,during which time the initial As(Ⅲ) concentrations were increased in a stepwise manner from l to 10-12 mmol/L.As(Ⅲ) oxidation activity of the enrichment culture gradually improved,and 10-12 mmol/L As(Ⅲ) was almost completely oxidized within four days.Terminal restriction fragment length polymorphism analysis showed that the dominant bacteria in the enrichment culture varied drastically during the enrichment process depending on the As(Ⅲ) concentration.Isolation and characterization of bacteria in the enrichment culture revealed that the presence of multiple CAOs with various As(Ⅲ) oxidation abilities enabled the culture to adapt to a wide range of As(Ⅲ) concentrations.The CAOs enrichment culture constructed here may he useful for pretreatment of water from which arsenic is being removed.

  11. Performance and influencing factors of halophilic activated sludge in denitrifying of nitrite%嗜盐污泥反硝化亚硝酸盐的性能及其影响因素

    崔有为; 丁洁然; 卢鹏飞; 彭永臻

    2012-01-01

    淡水污泥反硝化高盐废水受到盐度抑制而导致处理的失败.为了突破高盐废水脱氮的技术瓶颈,本研究通过采集人海口河底泥发展嗜盐脱氮生物系统实现了高盐废水的脱氮.本文系统地探讨了盐度、温度、pH和碳源类型等关键影响因素对嗜盐污泥反硝化亚硝酸的影响.试验结果表明:采集人海口底泥发展的嗜盐系统可以以亚硝酸盐作为电子受体进行反硝化.在38 g·L-1盐度下,嗜盐反硝化菌以甲醇作为碳源的最大反硝化速率为3.29 mg N·(g VSS)-1·h-1.系统最适宜盐度为15~51 g· L-1,最佳pH范围为8.0~9.0.反硝化碳源类型影响着反硝化速率.在测试的4种碳源类型中,嗜盐反硝化污泥利用甲醇进行反硝化较快.作为新认知的生物系统,确定高盐废水嗜盐生物处理系统的反硝化特性和影响因素对于实现高盐废水的高效处理具有重要的意义.%It is not successful to denitrify waste-water with high content of salt by freshwater activated sludge because of salinity choking. To overcome this problem, halophilic activated sludge must be developed. In this study, activated sediment at estuary of a river was collected and cultured to get halophilic activated sludge. The effect of key factors, such as salinity, temperature, pH and carbon source etc. , on denitrifying-nitrite performance of the halophilic activated sludge was studied. The results show that nitrite can be denitrified by the halophilic system via utilizing it as electron acceptor. As a result, the halophilic activated sludge is of ability to denitrify highly saline wastewater. At 38 g · L-1 salinity environment,the maximum specific denitrification rate of the biological system is 3. 29 mg N · (g VSS)-1 · h-1. These key operation parameters were optimized for further engineering design; the optimal survival salinity is 15-51 g · L-1 and pH 8. 0-9. 0. Carbon source has a great influence on denitrification rate. Among

  12. Impacts of nitrogen application rates on the activity and diversity of denitrifying bacteria in the Broadbalk Wheat Experiment.

    Clark, Ian M; Buchkina, Natalya; Jhurreea, Deveraj; Goulding, Keith W T; Hirsch, Penny R

    2012-05-05

    Bacterial denitrification results in the loss of fertilizer nitrogen and greenhouse gas emissions as nitrous oxides, but ecological factors in soil influencing denitrifier communities are not well understood, impeding the potential for mitigation by land management. Communities vary in the relative abundance of the alternative dissimilatory nitrite reductase genes nirK and nirS, and the nitrous oxide reductase gene nosZ; however, the significance for nitrous oxide emissions is unclear. We assessed the influence of different long-term fertilization and cultivation treatments in a 160-year-old field experiment, comparing the potential for denitrification by soil samples with the size and diversity of their denitrifier communities. Denitrification potential was much higher in soil from an area left to develop from arable into woodland than from a farmyard manure-fertilized arable treatment, which in turn was significantly higher than inorganic nitrogen-fertilized and unfertilized arable plots. This correlated with abundance of nirK but not nirS, the least abundant of the genes tested in all soils, showing an inverse relationship with nirK. Most genetic variation was seen in nirK, where sequences resolved into separate groups according to soil treatment. We conclude that bacteria containing nirK are most probably responsible for the increased denitrification potential associated with nitrogen and organic carbon in this soil.

  13. Shifts in the microbial community, nitrifiers and denitrifiers in the biofilm in a full-scale rotating biological contactor.

    Peng, Xingxing; Guo, Feng; Ju, Feng; Zhang, Tong

    2014-07-15

    The objective of this study was to investigate the microbial community shifts, especially nitrifiers and denitrifiers, in the biofilm of two rotating biological contactor (RBC) trains with different running times along the plug flowpath. The microbial consortia were profiled using multiple approaches, including 454 high-throughput sequencing of the V3-V4 region of 16S rRNA gene, clone libraries, and quantitative polymerase chain reaction (qPCR). The results demonstrated that (1) the overall microbial community at different locations had distinct patterns, that is, there were similar microbial communities at the beginnings of the two RBC trains and completely different populations at the ends of the two RBC trains; (2) nitrifiers, including ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB, Nitrosomonas) and nitrite-oxidizing bacteria (NOB, Nitrospira), increased in relative abundance in the biofilm along the flowpath, whereas denitrifiers (Rhodanobacter, Paracoccus, Thauera, and Azoarcus) markedly decreased; (3) the AOA were subdominant to the AOB in all sampled sections; and (4) strong ecological associations were shown among different bacteria. Overall, the results of this study provided more comprehensive information regarding the biofilm community composition and assemblies in full-scale RBCs.

  14. Isolation of aerobic denitrifier and characteristics of enhanced nitrogen removal in concentric-circles reactor with diversion wall

    许晓毅; 汤丽娟; 罗固源; 蒋真玉

    2009-01-01

    Three strains of aerobic denitrifiers,named as AT3,AT6 and AT7,were isolated from concentric-circles reactor with diversion wall possessing simultaneous nitrification and denitrification (SND) effect of 69%. The three strains are all gram-positive and rod-shaped,and their colonial colors are pale yellow,milk white and pink,respectively. Combined with 16SrDNA sequence homology comparison and biochemical tests,AT3 and AT7 were identified to belong to Rhodococcus,and AT6 to Gordonia. These bacterial strains could grow well in the medium with potassium nitrate as nitrogen source and sodium citrate as carbon source. Based on the enhanced nitrogen removal experiments of selected bacteria mixture for activated sludge,the inoculum amount of 5% was supposed to be proper. The mixed biomass suspension of selected strains with PVA immobilization was put into the concentric-circles reactor in order to study the characteristics of enhanced nitrogen removal after amplifying cultivation with inoculated amount of 5%. The experimental results show that the average removal efficiencies of ammonia nitrogen (NH3-N) and total nitrogen (TN) in the reactor enhanced with aerobic denitrifying bacteria using PVA are 92.18% and 79.14% respectively,increasing by 5.29% and 7.83% respectively compared with removal effects of control group without strains enhancement.

  15. Removal of nitrogen and phosphorus from the secondary effluent in tertiary denitrifying biofilters combined with micro-coagulation.

    Wei, Nan; Shi, Yunhong; Wu, Guangxue; Hu, Hongying; Guo, Yumei; Wu, Yihui; Wen, Hui

    2016-01-01

    Effective control of nitrogen and phosphorus in secondary effluent can reduce or avoid the eutrophication of receiving water bodies. Two denitrifying biofilters (DNBFs) packed with different sizes of quartz sands combined with micro-coagulation were operated for simultaneous removal of nitrogen and phosphorus from the secondary effluent. The quartz sand size in one DNBF was 2-4 mm (DNBFS), and in the other was 4-6 mm (DNBFL). In both DNBFs, methanol was used as the electron donor and different organic carbon to nitrogen (C/N) ratios were applied. Under C/N ratios of 1.5, 1.25, and 0.75 g/g, the nitrate nitrogen (NO3(-)-N) removal percentages were 73%, 77%, and 50% in DNBFS, and 43%, 25%, and 21% in DNBFL; the effluent total phosphorus concentrations were 0.15, 0.14, and 0.18 mg/L in DNBFS, and 0.29, 0.35, and 0.24 mg/L in DNBFL. The performance of both biofilters was quite stable within a backwashing cycle. The NO3(-)-N reduction rates were 1.31, 1.10, and 0.48 mg/(L·min) in DNBFS, and 0.97, 0.27, and 0.10 mg/(L·min) in DNBFL. For biomass detached from both biofilters, their denitrifying activities were similar. Biofilm biomass in DNBFS was higher than that in DNBFL, inducing a high denitrification efficiency in DNBFS.

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

    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.

  17. 好氧反硝化菌的筛选鉴定及其脱氮特性研究%SCREENING, IDENTIFICATION AND DENITRIFICATION CHARACTERISTICS OF AEROBIC DENITRIFIERS

    张宇燕; 贺根和; 陆丽君; 刘佳; 黄翔峰; 梁亮亮

    2014-01-01

    通过分离筛选获得3株好氧反硝化菌S1、S2和S3,初步鉴定S1为土生拉乌尔菌属(Raoultella terrigena), S2和S3均为解鸟氨酸拉乌尔菌属(Raoultella ornithinolytica)。这3株菌为好氧反硝化菌属首次报道,对其好氧反硝化脱氮特性的研究结果表明,培养液中氮含量的大幅变化均发生于菌株的对数生长期;在以硝酸盐或亚硝酸盐为唯一氮源的研究中,NO3--N和NO2--N的24 h去除率分别约为26%和67%,说明这3株菌更容易利用亚硝酸盐进行好氧反硝化;而且研究结果还表明,S3为脱氮效率最优的菌株,对低氮浓度的富营养化水质有较好的反硝化效果,4 h时S3的反硝化速率最大,达0.62 mg·L-1·h-1,对TN的反硝化脱氮贡献率可达52.5%。%Three aerobic denitrifiers(S1, S2 and S3)were abtained by isolating and screening. Strain S1 was identified as Raoultella terrigena, while strains S2 and S3 were identified as Raoultella ornithinolytica. It is first reported that the three bacteria are aerobic denitrifiers. Studies on their aerobic denitrification characteristics showed that significant changes of nitrogen level in culture media occurred in the logarithmic growth phase of strains; in the studies on using nitrate or nitrite as sole nitrogen source, respectively, the removal rates of NO3--N and NO2--N were 26%and 67%at 24 h, respectively, which proved that nitrite was used more easily for aerobic denitrification of three strains;Results also showed that S3 was optimal strain with the highest removal efficiency of nitrogen, which had better denitrification effects on eutrophic water with low concentration nitrogen, and S3 had the highest denitrification rate of 0.62 mg·L-1·h-1 and denitrification contribution rate of TN up to 52.5%at 4 h.

  18. ISOLATION, IDENTIFICATION OF AN AEROBIC DENITRIFIER AND ITS EFFECT OF NITROGEN REMOVAL%一株好氧反硝化细菌的筛选鉴定及其脱氮效果

    贺根和; 梁亮亮; 尹丽; 肖小雨

    2014-01-01

    An aerobic denitrifying bacteria was isolated from the sludge of municipal waste water treatment plant by enrichment and denitrification potential test, and identified through 16S rDNA sequence analysis. Then it was inoculated into simulation of eutrophication system, aiming to enhance the denitrification capacity. The strain was identified as Klebsiella sp. and designated HLNR05. It could remove 96.6% or 92.1% of the nitrate nitrogen and the total nitrogen at 24 h, respectively. Moreover, the nitrogen which was removed from the inoculation system is higher than assimilated into the cell. In addition, it could remove 91.4% and 88.2% of the nitrate nitrogen and the total nitrogen in the simulated eutrophic wastewater system at 24 h, respectively. It can be concluded that the aerobic denitrifier has a strong ability of aerobic denitrification.%经过富集培养和反硝化能力测定,从城市污水处理厂活性污泥中筛选得到1株好氧反硝化细菌。通过16S rDNA 同源性分析对该菌进行分子鉴定,并将菌接种到模拟富营养化水体中以探究其对系统中硝态氮和总氮的去除能力。结果表明,该菌属于Klebsiella sp.,命名为 HLNR05。菌株HLNR05在24 h内NO3--N的去除率达96.6%, TN去除率达92.1%,而且其从培养体系中完全去除的氮明显多于同化到细胞的氮。利用HLNR05处理模拟富营养化废水,结果发现其在24 h内对模拟废水中的NO3--N和TN去除率达91.4%和88.2%。表明菌株HLNR05具有较强的好氧反硝化能力。

  19. Insights into the effect of soil pH on N(2)O and N(2) emissions and denitrifier community size and activity.

    Cuhel, Jirí; Simek, Miloslav; Laughlin, Ronnie J; Bru, David; Chèneby, Dominique; Watson, Catherine J; Philippot, Laurent

    2010-03-01

    The objective of this study was to investigate how changes in soil pH affect the N(2)O and N(2) emissions, denitrification activity, and size of a denitrifier community. We established a field experiment, situated in a grassland area, which consisted of three treatments which were repeatedly amended with a KOH solution (alkaline soil), an H(2)SO(4) solution (acidic soil), or water (natural pH soil) over 10 months. At the site, we determined field N(2)O and N(2) emissions using the (15)N gas flux method and collected soil samples for the measurement of potential denitrification activity and quantification of the size of the denitrifying community by quantitative PCR of the narG, napA, nirS, nirK, and nosZ denitrification genes. Overall, our results indicate that soil pH is of importance in determining the nature of denitrification end products. Thus, we found that the N(2)O/(N(2)O + N(2)) ratio increased with decreasing pH due to changes in the total denitrification activity, while no changes in N(2)O production were observed. Denitrification activity and N(2)O emissions measured under laboratory conditions were correlated with N fluxes in situ and therefore reflected treatment differences in the field. The size of the denitrifying community was uncoupled from in situ N fluxes, but potential denitrification was correlated with the count of NirS denitrifiers. Significant relationships were observed between nirS, napA, and narG gene copy numbers and the N(2)O/(N(2)O + N(2)) ratio, which are difficult to explain. However, this highlights the need for further studies combining analysis of denitrifier ecology and quantification of denitrification end products for a comprehensive understanding of the regulation of N fluxes by denitrification.

  20. Denitrifying Phosphorus Removal in MUCT-MBR%MUCT-MBR工艺反硝化除磷脱氮研究

    刘鹏霄; 张捍民; 王晓琳; 肖景霓; 杨凤林

    2009-01-01

    自行设计的双反应器MUCT-MBR简化了MUCT工艺,将反应池由5个简化到2个,减小了工艺占地面积,并且采用膜过滤取代二沉池出水,操作简单,出水安全可靠.针对MUCT-MBR工艺脱氮除磷性能,尤其是反硝化除磷功能进行研究.结果表明,当进水C/N/P比在33.3/5/1~25/5.5/1范围内,整个实验过程中COD、TN和TP平均去除率分别达到89.3%、75.4%、79.2%;且膜出水不受污泥沉降性的影响.缺氧段的反硝化吸磷是MUCT-MBR工艺除磷的关键,系统运行至第58 d,系统中反硝化除磷菌(DPAOs)所占比例达84.2%,反硝化除磷占系统总磷去除的67.07%.%The self-designed MUCT-MBR simplifies the MUCT process with reducing reactors from 5 to 2, which greatly reduces land occupied by equipment. Instead of secondary sedimentation tank, the. membrane effluent quality is quite safe, and the operation is simple. In the investigation about simultaneous phosphorus and nitrogen removal of MUCT-MBR, the results showed that: when the proportions of C, N and P in the influent were 33.3/5/1-25/5.5/1, the average removal rate of COD, TN and TP in the whole experimental process were 89.3%,75.4% and 79.2 % , respectively. And the sludge settling capacity had no influence on the membrane effluent quality. The key factor of N and P removal rates is denitrifying phosphorus removal in anoxic condition. The proportion of denitrifying phosphate accumulating organisms (DPAOs) and the rate of denitrifying phosphorous removal were 84.2% and 67.07% on the 58th day, respectively.

  1. Autotrophic carbon dioxide fixation via the Calvin-Benson-Bassham cycle by the denitrifying methanotroph "Candidatus Methylomirabilis oxyfera".

    Rasigraf, Olivia; Kool, Dorien M; Jetten, Mike S M; Sinninghe Damsté, Jaap S; Ettwig, Katharina F

    2014-04-01

    Methane is an important greenhouse gas and the most abundant hydrocarbon in the Earth's atmosphere. Methanotrophic microorganisms can use methane as their sole energy source and play a crucial role in the mitigation of methane emissions in the environment. "Candidatus Methylomirabilis oxyfera" is a recently described intra-aerobic methanotroph that is assumed to use nitric oxide to generate internal oxygen to oxidize methane via the conventional aerobic pathway, including the monooxygenase reaction. Previous genome analysis has suggested that, like the verrucomicrobial methanotrophs, "Ca. Methylomirabilis oxyfera" encodes and transcribes genes for the Calvin-Benson-Bassham (CBB) cycle for carbon assimilation. Here we provide multiple independent lines of evidence for autotrophic carbon dioxide fixation by "Ca. Methylomirabilis oxyfera" via the CBB cycle. The activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), a key enzyme of the CBB cycle, in cell extracts from an "Ca. Methylomirabilis oxyfera" enrichment culture was shown to account for up to 10% of the total methane oxidation activity. Labeling studies with whole cells in batch incubations supplied with either (13)CH4 or [(13)C]bicarbonate revealed that "Ca. Methylomirabilis oxyfera" biomass and lipids became significantly more enriched in (13)C after incubation with (13)C-labeled bicarbonate (and unlabeled methane) than after incubation with (13)C-labeled methane (and unlabeled bicarbonate), providing evidence for autotrophic carbon dioxide fixation. Besides this experimental approach, detailed genomic and transcriptomic analysis demonstrated an operational CBB cycle in "Ca. Methylomirabilis oxyfera." Altogether, these results show that the CBB cycle is active and plays a major role in carbon assimilation by "Ca. Methylomirabilis oxyfera" bacteria. Our results suggest that autotrophy might be more widespread among methanotrophs than was previously assumed and implies that a methanotrophic

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

    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.

  3. The diversity of denitrifying bacteria in the alpine meadow soil of Sanjiangyuan natural reserve in Tibet Plateau

    XU Haiping; ZHANG Yuguang; SUN Yanping; LI Diqiang; CHEN Xinmou; WANG Huimin; XIAO Qiming; LIU Xueduan

    2006-01-01

    This is the first time to describe the diversity of denitrifying bacteria in Sanjiangyuan natural reserve in Tibet Plateau by investigating the molecular diversity and phylogenetic analysis of nirK and nosZ genes using PCR-RFLP and sequencing. Four soil samples were collected from alpine meadow communities from over an altitude of 4600 m which had different physicochemical properties by principal component analysis (PCA). For the genes fragment of nirKand nosZ, the diverse PCR products were characterized by cloning, restriction fragment length polymorphism (RFLP) analysis and sequenced. A total of 253 nirK clones and 283 nosZ clones were received in four samples, and 78 operational taxonomic units (OTUs) of nirK and 120 OTUs of nosZ by the restriction enzymes Mspl and Rsal digested. The analysis of environmental factors showed that altitude and C/N ratio in soil may be the key factors to the denitrifying bacteria community. 36 nirK clones and 17 nosZ clones were sequenced, and their levels of nucleotide identity were from 69% to 98% and 57% to 97%, respectively. The phylogenetic tree was constructed using the Clustal W and Mega softwares, and all the sequenced clones could be subdivided into 4 groups. Some of clone sequences were related to the nirK and nosZ genes belonging to three phylogenetic subdivisions (α-, β- and Y subclasses of the Proteobacteria), while most of the clones were closely related to the genes of the uncultured bacteria. The sequence distributions were not clear relating to the sample sites in the tree.

  4. Comparison of endogenous metabolism during long-term anaerobic starvation of nitrite/nitrate cultivated denitrifying phosphorus removal sludges.

    Wang, Yayi; Zhou, Shuai; Wang, Hong; Ye, Liu; Qin, Jian; Lin, Ximao

    2015-01-01

    Denitrifying phosphorus removal (DPR) by denitrifying phosphorus-accumulating organisms (DPAOs) is a promising approach for reducing energy and carbon usage. However, influent fluctuations or interruptions frequently expose the DPAOs biomass to starvation conditions, reducing biomass activity and amount, and ultimately degrading the performance of DPR. Therefore, a better understanding of the endogenous metabolism and recovery ability of DPAOs is urgently required. In the present study, anaerobic starvation (12 days) and recovery were investigated in nitrite- and nitrate-cultivated DPAOs at 20 ± 1 °C. The cell decay rates in nitrite-DPAOs sludges from the end of the anaerobic and aerobic phase were 0.008 day⁻¹ and 0.007 day⁻¹, respectively, being 64% and 68% lower than those of nitrate-DPAOs sludges. Nitrite-DPAOs sludges also recovered more rapidly than nitrate-DPAOs sludge after 12 days of starvation. The maintenance energy of nitrite-DPAOs sludges from the end of the anaerobic and aerobic phase were approximately 31% and 34% lower, respectively, than those of nitrate-DPAOs sludges. Glycogen and polyphosphate (poly-P) sequentially served as the main maintenance energy sources in both nitrite-and nitrate-DPAOs sludges. However, the transformation pathway of the intracellular polymers during starvation differed between them. Nitrate-DPAOs sludge used extracellular polymeric substances (EPS) (mainly polysaccharides) as an additional maintenance energy source during the first 3 days of starvation. During this phase, EPS appeared to contribute to 19-27% of the ATP production in nitrate-DPAOs, but considerably less to the cell maintenance of nitrite-DPAOs. The high resistance of nitrite-DPAOs to starvation might be attributable to frequent short-term starvation and exposure to toxic substances such as nitrite/free nitrous acids in the parent nitrite-fed reactor. The strong resistance of nitrite-DPAOs sludge to anaerobic starvation may be exploited in P removal

  5. Denitrifying bacteria from the genus Rhodanobacter dominate bacterial communities in the highly contaminated subsurface of a nuclear legacy waste site.

    Green, Stefan J; Prakash, Om; Jasrotia, Puja; Overholt, Will A; Cardenas, Erick; Hubbard, Daniela; Tiedje, James M; Watson, David B; Schadt, Christopher W; Brooks, Scott C; Kostka, Joel E

    2012-02-01

    The effect of long-term mixed-waste contamination, particularly uranium and nitrate, on the microbial community in the terrestrial subsurface was investigated at the field scale at the Oak Ridge Integrated Field Research Challenge (ORIFRC) site in Oak Ridge, TN. The abundance, community composition, and distribution of groundwater microorganisms were examined across the site during two seasonal sampling events. At representative locations, subsurface sediment was also examined from two boreholes, one sampled from the most heavily contaminated area of the site and another from an area with low contamination. A suite of DNA- and RNA-based molecular tools were employed for community characterization, including quantitative PCR of rRNA and nitrite reductase genes, community composition fingerprinting analysis, and high-throughput pyrotag sequencing of rRNA genes. The results demonstrate that pH is a major driver of the subsurface microbial community structure and that denitrifying bacteria from the genus Rhodanobacter (class Gammaproteobacteria) dominate at low pH. The relative abundance of bacteria from this genus was positively correlated with lower-pH conditions, and these bacteria were abundant and active in the most highly contaminated areas. Other factors, such as the concentration of nitrogen species, oxygen level, and sampling season, did not appear to strongly influence the distribution of Rhodanobacter bacteria. The results indicate that these organisms are acid-tolerant denitrifiers, well suited to the acidic, nitrate-rich subsurface conditions, and pH is confirmed as a dominant driver of bacterial community structure in this contaminated subsurface environment.

  6. Thermal breeder fuel enrichment zoning

    Capossela, Harry J.; Dwyer, Joseph R.; Luce, Robert G.; McCoy, Daniel F.; Merriman, Floyd C.

    1992-01-01

    A method and apparatus for improving the performance of a thermal breeder reactor having regions of higher than average moderator concentration are disclosed. The fuel modules of the reactor core contain at least two different types of fuel elements, a high enrichment fuel element and a low enrichment fuel element. The two types of fuel elements are arranged in the fuel module with the low enrichment fuel elements located between the high moderator regions and the high enrichment fuel elements. Preferably, shim rods made of a fertile material are provided in selective regions for controlling the reactivity of the reactor by movement of the shim rods into and out of the reactor core. The moderation of neutrons adjacent the high enrichment fuel elements is preferably minimized as by reducing the spacing of the high enrichment fuel elements and/or using a moderator having a reduced moderating effect.

  7. Comparison between traditional biological phosphorus removal by anaerobic/aerobic and denitrifying phosphorus removal by anaerobic/aerobic%传统厌氧/好氧生物除磷与厌氧/缺氧反硝化除磷效能的比较

    苏婉琳; 韩萍芳

    2011-01-01

    采用序批式反应器(SBR),对比厌氧/好氧(A/O)和厌氧/缺氧(A/A)2种运行模式对模拟生活和工业混合污水同时脱氮除磷的效能.结果表明:反硝化聚磷菌完全可以在厌氧/缺氧交替运行条件下得到富集,稳定运行的2种模式对有机物和P的去除率分别保持在90%和85%以上,且A/A SBR具有更强的释磷能力,其释磷量比A/O SBR高出1.2倍.进一步试验表明:磷的释放在有无硝酸盐的情况下效果是不同的.2个系统内污泥均有反硝化除磷能力,A/A SBR中所含反硝化聚磷菌(DPAO)的比例是A/O SBR的4.56倍.2种模式出水水质都能取得较好的效果,且能实现同步除磷脱氮,而反硝化除磷在生物除磷方面更具优势.%Two sequence batch reactors(SBRs) in A/O and A/A run modes were operated in parallel to compare their ability of simultaneous phosphorus and nitrogen removal. The results showed that the ability of the anaerobic/anoxic strategy enriched the growth of denitrifying phosphorus bacteria capable of taking up phosphate under anoxic condition, and the removal of COD and phosphorus were averaged over 90% and 85% in the steady-state, respectively. A/A SBR had the stronger anaerobic phosphorus release ability; its amount of anaerobic released phosphorus is higher than 1. 2 times compared with A/O SBR. It is shown that interpretation of phosphorus release tests with or without nitrate present was different. The proportion of denitrifying phosphate accumulating organism ( DPAO) was 4. 56 times compared with the one of A/O SBR. The qualities of effluent were met the criteria, and DPAO systems could obtaia get simultaneous denitrifying and phosphorus removal. Thus, DPAO had more advantages than PAO for biological phosphorus removal.

  8. [Influences of long-term application of organic and inorganic fertilizers on the composition and abundance of nirS-type denitrifiers in black soil].

    Yin, Chang; Fan, Fen-Liang; Li, Zhao-Jun; Song, A-Lin; Zhu, Ping; Peng, Chang; Liang, Yong-Chao

    2012-11-01

    The objectives of this study were to explore the effects of long-term organic and inorganic fertilizations on the composition and abundance of nirS-type denitrifiers in black soil. Soil samples were collected from 4 treatments (i. e. no fertilizer treatment, CK; organic manure treatment, OM; chemical fertilizer treatment (NPK) and combination of organic and chemical fertilizers treatment (MNPK)) in Gongzhuling Long-term Fertilization Experiment Station. Composition and abundance of nirS-type denitrifiers were analyzed with terminal restriction fragment length polymorphism (T-RFLP) and real-time quantitative PCR (Q-PCR), respectively. Denitrification enzyme activity (DEA) and soil properties were also measured. Application of organic fertilizers (OM and MNPK) significantly increased the DEAs of black soil, with the DEAs in OM and MNPK being 5.92 and 6.03 times higher than that in CK treatment, respectively, whereas there was no significant difference between NPK and CK. OM and MNPK treatments increased the abundances of nirS-type denitrifiers by 2.73 and 3.83 times relative to that of CK treatment, respectively. The abundance of nirS-type denitrifiers in NPK treatment was not significantly different from that of CK. The T-RFLP analysis of nirS genes showed significant differences in community composition between organic and inorganic treatments, with the emergence of a 79 bp T-RF, a significant decrease in relative abundance of the 84 bp T-RF and a loss of the 99 bp T-RF in all organic treatments. Phylogenetic analysis indicated that the airS-type denitrifiers in the black soil were mainly composed of alpha, beta and gamma-Proteobacteria. The 79 bp-type denitrifiers inhabiting exclusively in organic treatments (OM and MNPK) were affiliated to Pseudomonadaceae in gamma-Proteobacteria and Burkholderiales in beta-Proteobacteria. The 84 bp-types were related to Burkholderiales and Rhodocyclales. Correlation analysis indicated that pH, concentrations of total nitrogen

  9. A novel denitrifying methanotroph of the NC10 phylum and its microcolony

    He, Zhanfei; Cai, Chaoyang; Wang, Jiaqi; Xu, Xinhua; Zheng, Ping; Jetten, Mike S. M.; Hu, Baolan

    2016-09-01

    The NC10 phylum is a candidate phylum of prokaryotes and is considered important in biogeochemical cycles and evolutionary history. NC10 members are as-yet-uncultured and are difficult to enrich, and our knowledge regarding this phylum is largely limited to the first species ‘Candidatus Methylomirabilis oxyfera’ (M. oxyfera). Here, we enriched NC10 members from paddy soil and obtained a novel species of the NC10 phylum that mediates the anaerobic oxidation of methane (AOM) coupled to nitrite reduction. By comparing the new 16S rRNA gene sequences with those already in the database, this new species was found to be widely distributed in various habitats in China. Therefore, we tentatively named it ‘Candidatus Methylomirabilis sinica’ (M. sinica). Cells of M. sinica are roughly coccus-shaped (0.7–1.2 μm), distinct from M. oxyfera (rod-shaped; 0.25–0.5 × 0.8–1.1 μm). Notably, microscopic inspections revealed that M. sinica grew in honeycomb-shaped microcolonies, which was the first discovery of microcolony of the NC10 phylum. This finding opens the possibility to isolate NC10 members using microcolony-dependent isolation strategies.

  10. Survival of indicator organisms during enrichment on tetrachloroethene.

    Skramstad, J D; Hurst, C J; Novak, P J

    2003-01-01

    A laboratory study was performed as the basis for a full-scale bioaugmentation project at a site contaminated with chlorinated ethenes. The objectives of this study were to 1) develop a protocol to enrich for a tetrachloroethene (PCE)-dechlorinating culture from waste activated sludge and anaerobic digester biosolids and 2) monitor the survival of fecal coliform bacteria and bacteriophage, which model enteric viruses, during the enrichment process. A culture was enriched in 8 days with the ability to degrade 6-microM PCE to cis-dichloroethene. Using the enrichment protocol in two identical experiments, significant inactivation of fecal coliform bacteria (2 log) and somatic coliphage (0.33 log) was observed in one of the experiments; no inactivation occurred in the second experiment. The number of F-specific coliphage decreased in both experiments (0.87 and 1.26 log inactivation). Despite the decrease in some of the coliform and bacteriophage numbers, the quantity of organisms and phage particles present after enrichment was still high (approximately 7.5 x 10(5) most probable number/L, 6.9 x 10(6) plaque-forming units (PFU)/L, and 3.3 x 10(5) PFU/L, for fecal coliform bacteria, somatic coliphage, and F-specific coliphage, respectively). This may be cause for concern, depending on the current and future groundwater use at or near a site undergoing bioaugmentation with cultures derived from waste activated sludge and anaerobic digester biosolids.

  11. Evidence for the biogenic origin of manganese-enriched layers in Lake Superior sediments.

    Palermo, Christine; Dittrich, Maria

    2016-04-01

    Manganese (Mn) and iron (Fe)-enriched sediment layers were discovered in Lake Superior within, above and below the oxic-anoxic interface. While the role of bacteria in redox reactions with Mn is known to be significant, little information exists about indigenous microbial communities in many freshwater environments. This study examined the bacterial communities of Mn-enriched layers in Lake Superior to identify the potential Mn(II) oxidizers responsible for the formation of Mn oxides. Anaerobic Mn(II) oxidation occurring in the Mn-enriched layers at the oxic-anoxic interface was investigated using Mn(II)-enriched cultures. High-resolution microscopic and spectroscopic investigations provided evidence of the biogenic formation of Mn oxides on cell surfaces. Spectroscopic mapping confirmed high levels of Mn in structures resembling biogenic Mn oxides. These structures were observed in enrichment cultures and in Mn-enriched layer sediment samples, indicating the significance of biogenic Mn oxidation occurring in situ. 16S ribosomal DNA pyrosequencing was used to identify the bacteria potentially responsible for Mnoxide formation in the enrichment cultures and Mn-enriched layers, revealing that the Mn-enriched layer contains classes with known Mn(II)-oxidizing members. Pyrosequencing of bacterial cultures suggested that these bacteria may be Bacillus strains, and that anaerobic microbial-mediated Mn(II) oxidation contributes to the formation of the layers.

  12. Effect of interactions between carbon dioxide enrichment and NH4+/NO3- ratio on pH of culturing nutrient solution,growth and vigor of tomato root system

    Juan LI; Jianmin ZHOU

    2008-01-01

    A growth chamber experiment was conducted to investigate the influence of NH4+/NO3- ratio and elevated CO2 concentration on the pH in nutrient solution,growth and root vigor system of tomato seedling roots,which attempts to understand whether the elevated CO2 concentration can alleviate the harmful effects of higher NH4+-N concentration in nutrient solutions on the tomato root system.Tomato (Lycopersicon esculenturn Mill.var.Hezuo 906) was grown in pots with nutrient solutions varying in NH4+/NO3- ratio (0:1,1:3,1:1,3:1and 1:0) and the growth chambers were supplied with with the growth process and CO2 concentration increased.At both CO2 levels,pH increased when 100% NO3--N was supplied and decreased in other treatments.The pH decrease in the nutrient solution was directly correlated to the NH4+-N proportion.The pH value was more reduced in 100% NH4+-N nutrient solution than increased in the 100% NO3--N nutrient solution.CO2 enrichment increased the dry weight of shoots and roots,root vigor system,total absorbing area and active absorbing area of tomato seedlings.All the measurement indexes above were increased in the elevated CO2 concentration treatment with the NO3- proportion increase in the nutrient solutions.Thus,under the elevated CO2 concentration,the dry weights of shoots and roots,root vigor system,total root absorbing area and active absorbing area were found to be inversely correlated to NH4+/NO3- ratio,leading to about 65.8%,78.0%,18.9%,12.9% and 18.9% increase,respectively,compared with that under the ambient CO2 concentration.Our results indicated that tomato seedling roots may benefit mostly from CO2 enrichment when 100% NO3--N nutrient solutions was supplied,but the CO2 concentration elevation did not alleviate the harmful effects when 100% NHa+-N was supplied.

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

    Iolanda Cristina Silveira Duarte

    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.

  14. 构建一种高产量小胶质细胞体外纯化培养的方法%A new method for culturing highly enriched microglia in vitro

    魏桂荣; 张敏; 董继华; 梅元武; 刘仁刚

    2005-01-01

    BACKGROUND: Microglial cells are prominently involved in certain neurologic diseases such as Parkinson disease and Alzeheimer disease. In vitro primary culture is commonly used in studies on the functions of microglia.However, these classical culture methods have some defects including complex procedures and low out-put.OBJECTIVE: To establish a simplified high-output primary culture of microglia.DESIGN: An explorative experiment with microglial cells as the single sample.SETTING: Department of Neurology, Affiliated Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.MATERIALS: The study was finished at the Central Laboratory of Union Hospital from April to October 2004. Microglial cells were obtained from 10 newborn(one day) male Kunming mice that were selected.METHODS: The author' s culture method was based on McCarthy method, we developed a new culture method and made some improvements,including the increased cell density for primary culture and nutritional deprivation. The microlglial cells were isolated with low-concentration trypsin-EDTA(ethylene diamine tetraacetic acid) digestion and immunochemically labeled with MAC-1 antibody, so as to measure the output and purity of microglia.MAIN OUTCOME MEASURES: ① Morphologic features of microglial cells, observed with inverted microscope; ② Purity and activity of microglia cultured with these two methods, were measured immunohistochemically.RESULTS: For microglia cultured with McCarthy method, the culture cycle was 20 days and the output was 2 × l05 cells per flask with a purity of 95% -97%. The new method shortened the culture cycle to 15 days and the output reached 1 × 106 cells per flask with a purity of 96-98%. Cell purity and activity had no significant difference between these two culture methods.CONCLUSION: The new method has a similar purity and activity with classical method; however, it may simplify procedures, shorten cycle, and increase output, and therefore can be

  15. Hydrogen-enriched fuels

    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.

  16. CLEAN: CLustering Enrichment ANalysis

    Medvedovic Mario

    2009-07-01

    Full Text Available Abstract Background Integration of biological knowledge encoded in various lists of functionally related genes has become one of the most important aspects of analyzing genome-wide functional genomics data. In the context of cluster analysis, functional coherence of clusters established through such analyses have been used to identify biologically meaningful clusters, compare clustering algorithms and identify biological pathways associated with the biological process under investigation. Results We developed a computational framework for analytically and visually integrating knowledge-based functional categories with the cluster analysis of genomics data. The framework is based on the simple, conceptually appealing, and biologically interpretable gene-specific functional coherence score (CLEAN score. The score is derived by correlating the clustering structure as a whole with functional categories of interest. We directly demonstrate that integrating biological knowledge in this way improves the reproducibility of conclusions derived from cluster analysis. The CLEAN score differentiates between the levels of functional coherence for genes within the same cluster based on their membership in enriched functional categories. We show that this aspect results in higher reproducibility across independent datasets and produces more informative genes for distinguishing different sample types than the scores based on the traditional cluster-wide analysis. We also demonstrate the utility of the CLEAN framework in comparing clusterings produced by different algorithms. CLEAN was implemented as an add-on R package and can be downloaded at http://Clusteranalysis.org. The package integrates routines for calculating gene specific functional coherence scores and the open source interactive Java-based viewer Functional TreeView (FTreeView. Conclusion Our results indicate that using the gene-specific functional coherence score improves the reproducibility of the

  17. Soil environmental conditions and microbial build-up mediate the effect of plant diversity on soil nitrifying and denitrifying enzyme activities in temperate grasslands.

    Xavier Le Roux

    Full Text Available Random reductions in plant diversity can affect ecosystem functioning, but it is still unclear which components of plant diversity (species number - namely richness, presence of particular plant functional groups, or particular combinations of these and associated biotic and abiotic drivers explain the observed relationships, particularly for soil processes. We assembled grassland communities including 1 to 16 plant species with a factorial separation of the effects of richness and functional group composition to analyze how plant diversity components influence soil nitrifying and denitrifying enzyme activities (NEA and DEA, respectively, the abundance of nitrifiers (bacterial and archaeal amoA gene number and denitrifiers (nirK, nirS and nosZ gene number, and key soil environmental conditions. Plant diversity effects were largely due to differences in functional group composition between communities of identical richness (number of sown species, though richness also had an effect per se. NEA was positively related to the percentage of legumes in terms of sown species number, the additional effect of richness at any given legume percentage being negative. DEA was higher in plots with legumes, decreased with increasing percentage of grasses, and increased with richness. No correlation was observed between DEA and denitrifier abundance. NEA increased with the abundance of ammonia oxidizing bacteria. The effect of richness on NEA was entirely due to the build-up of nitrifying organisms, while legume effect was partly linked to modified ammonium availability and nitrifier abundance. Richness effect on DEA was entirely due to changes in soil moisture, while the effects of legumes and grasses were partly due to modified nitrate availability, which influenced the specific activity of denitrifiers. These results suggest that plant diversity-induced changes in microbial specific activity are important for facultative activities such as denitrification

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

    2015-01-01

    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%, ...

  19. Riboflavin Reduces Pro-Inflammatory Activation of Adipocyte-Macrophage Co-culture. Potential Application of Vitamin B2 Enrichment for Attenuation of Insulin Resistance and Metabolic Syndrome Development

    Agnieszka Irena Mazur-Bialy

    2016-12-01

    Full Text Available Due to the progressive increase in the incidence of obese and overweight individuals, cardiometabolic syndrome has become a worldwide pandemic in recent years. Given the immunomodulatory properties of riboflavin, the current study was performed to investigate the potency of riboflavin in reducing obesity-related inflammation, which is the main cause of insulin resistance, diabetes mellitus 2 or arteriosclerosis. We determined whether pretreatment with a low dose of riboflavin (10.4–1000 nM affected the pro-inflammatory activity of adipocyte-macrophage co-culture (3T3 L1-RAW 264.7 following lipopolysaccharide stimulation (LPS; 100 ng/mL which mimics obesity-related inflammation. The apoptosis of adipocytes and macrophages as well as tumor necrosis factor-alpha (TNF-α, interleukin 6 (IL-6, interleukin 1beta (IL-1β, monocyte chemotactic protein 1 (MCP-1, high-mobility group box 1 (HMGB1, transforming growth factor–beta 1 (TGFβ, interleukin 10 (IL-10, inducible nitric oxide synthase (iNOS, nitric oxide (NO, matrix metalloproteinase 9 (MMP-9, tissue inhibitor of metalloproteinases-1 (TIMP-1 expression and release, macrophage migration and adipokines (adiponectin and leptin were determined. Our results indicated an efficient reduction in pro-inflammatory factors (TNFα, IL-6, MCP-1, HMGB1 upon culture with riboflavin supplementation (500–1000 nM, accompanied by elevation in anti-inflammatory adiponectin and IL-10. Moreover, macrophage migration was reduced by the attenuation of chemotactic MCP-1 release and degradation of the extracellular matrix by MMP-9. In conclusion, riboflavin effectively inhibits the pro-inflammatory activity of adipocyte and macrophage co-cultures, and therefore we can assume that its supplementation may reduce the likelihood of conditions associated with the mild inflammation linked to obesity.

  20. Effects of carbon-to-sulfur (C/S) ratio and nitrate (N) dosage on Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorus Removal (DS-EBPR)

    Yu, Mei; Lu, Hui; Wu, Di; Zhao, Qing; Meng, Fangang; Wang, Yudan; Hao, Xiaodi; Chen, Guang-Hao

    2016-03-01

    In this study, the Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorous Removal (DS-EBPR) with 20 mg P/L/d of the volumetric P removal rate was successfully achieved in a Sequencing Batch Reactor (SBR). The effects of carbon-to-sulfur (C/S) mass ratio and nitrate (N) dosage were investigated through two batch tests to reveal the role of wastewater compositions in DS-EBPR performance. The optimal specific P release and uptake rates (0.4 and 2.4 mg P/g VSS/h, respectively) were achieved at C/S/P/N mass ratio of 150/200/20/20, and poly-S is supplied as a potential electron and energy storage. The nitrate dosage in a range of 10–50 mg N/L had no significant influence on P uptake rates (2.1 ~ 2.4 mg P/g VSS/h), but significantly affected the storage of inclusion poly-S, the poly-S oxidation rate was increased about 16% while dosing nitrate from 20 to 30 mg N/L. It implies that nitrate is denitrified in the P uptake phase, and excess nitrate is further consumed by poly-S. Moreover, the microbial analysis showed that the functional bacteria should mostly belong to denitrifying bacteria or Unclassified genera.

  1. A doubling of microphytobenthos biomass coincides with a tenfold increase in denitrifier and total bacterial abundances in intertidal sediments of a temperate estuary.

    Helen Decleyre

    Full Text Available Surface sediments are important systems for the removal of anthropogenically derived inorganic nitrogen in estuaries. They are often characterized by the presence of a microphytobenthos (MPB biofilm, which can impact bacterial communities in underlying sediments for example by secretion of extracellular polymeric substances (EPS and competition for nutrients (including nitrogen. Pyrosequencing and qPCR was performed on two intertidal surface sediments of the Westerschelde estuary characterized by a two-fold difference in MPB biomass but no difference in MPB composition. Doubling of MPB biomass was accompanied by a disproportionately (ten-fold increase in total bacterial abundances while, unexpectedly, no difference in general community structure was observed, despite significantly lower bacterial richness and distinct community membership, mostly for non-abundant taxa. Denitrifier abundances corresponded likewise while community structure, both for nirS and nirK denitrifiers, remained unchanged, suggesting that competition with diatoms for nitrate is negligible at concentrations in the investigated sediments (appr. 1 mg/l NO3-. This study indicates that MPB biomass increase has a general, significantly positive effect on total bacterial and denitrifier abundances, with stimulation or inhibition of specific bacterial groups that however do not result in a re-structured community.

  2. A Contrastive Research on American-Chinese Cultural Identity from Perspective of Mass Culture

    赵欣

    2012-01-01

    The appearance and development of "Super Girl" accompanies with the rise of mass culture and it reflects the main features of mass culture.Meanwhile western mass cultural product especially the American mass cultural product "American Idol" influenced Chinese mass culture and it has produced massive impact on the identity of national cultural and cultural independence in China.The thesis can help to deepen and make up for the deficiency of mass culture theories,to enrich the applicational experience and the...

  3. Kinetics of p-aminoazobenzene degradation by Bacillus subtilis under denitrifying conditions

    Zissi, U.S.; Kornaros, M.E.; Lyberatos, G.C.

    1999-05-01

    Bacillus subtilis is an organism capable of degrading an azo dye, such as p-aminoazobenzene (pAAB), under both aerobic and anoxic conditions. In both cases, pAAB is co-metabolized with a main carbon source and under anoxic conditions denitrification is observed. Kinetic experiments were carried out with a pure culture of B. subtilis and a mathematical model that accurately describes both biodegradation of pAAB under anoxic conditions and the denitrification process under both carbon- and nitrate- or nitrite-limited conditions is developed. Presence of pAAB in culture medium causes an inhibition of bacterial growth and of nitrite accumulation. Bacterial growth and pAAB degradation rates are found to be slower under anoxic conditions compared to the corresponding rates under aerobic conditions.

  4. Enrichment and terminal differentiation of striated muscle progenitors in vitro

    Becher, Ulrich M.; Breitbach, Martin; Sasse, Philipp [Institute of Physiology I, Life and Brain Center, University of Bonn, Bonn (Germany); Garbe, Stephan [Department of Radiology, University of Bonn, Bonn (Germany); Ven, Peter F.M. van der [Institute for Cell Biology, University of Bonn, Bonn (Germany); Fuerst, Dieter O., E-mail: dfuerst@uni-bonn.de [Institute for Cell Biology, University of Bonn, Bonn (Germany); Fleischmann, Bernd K., E-mail: bernd.fleischmann@uni-bonn.de [Institute of Physiology I, Life and Brain Center, University of Bonn, Bonn (Germany)

    2009-10-01

    Enrichment and terminal differentiation of mammalian striated muscle cells is severely hampered by fibroblast overgrowth, de-differentiation and/or lack of functional differentiation. Herein we report a new, reproducible and simple method to enrich and terminally differentiate muscle stem cells and progenitors from mice and humans. We show that a single gamma irradiation of muscle cells induces their massive differentiation into structurally and functionally intact myotubes and cardiomyocytes and that these cells can be kept in culture for many weeks. Similar results are also obtained when treating skeletal muscle-derived stem cells and progenitors with Mitomycin C.

  5. Functional bacteria and process metabolism of the Denitrifying Sulfur conversion-associated Enhanced Biological Phosphorus Removal (DS-EBPR) system: An investigation by operating the system from deterioration to restoration.

    Guo, Gang; Wu, Di; Hao, Tianwei; Mackey, Hamish Robert; Wei, Li; Wang, Haiguang; Chen, Guanghao

    2016-05-15

    A sulfur conversion-associated Enhanced Biological Phosphorus (P) Removal (EBPR) system is being developed to cater for the increasing needs to treat saline/brackish wastewater resulting from seawater intrusion into groundwater and sewers and frequent use of sulfate coagulants during drinking water treatment, as well as to meet the demand for eutrophication control in warm climate regions. However, the major functional bacteria and metabolism in this emerging biological nutrient removal system are still poorly understood. This study was thus designed to explore the functional microbes and metabolism in this new EBPR system by manipulating the deterioration, failure and restoration of a lab-scale system. This was achieved by changing the mixed liquor suspended solids (MLSS) concentration to monitor and evaluate the relationships among sulfur conversion (including sulfate reduction and sulfate production), P removal, variation in microbial community structures, and stoichiometric parameters. The results show that the stable Denitrifying Sulfur conversion-associated EBPR (DS-EBPR) system was enriched by sulfate-reducing bacteria (SRB) and sulfide-oxidizing bacteria (SOB). These bacteria synergistically participated in this new EBPR process, thereby inducing an appropriate level of sulfur conversion crucial for achieving a stable DS-EBPR performance, i.e. maintaining sulfur conversion intensity at 15-40 mg S/L, corresponding to an optimal sludge concentration of 6.5 g/L. This range of sulfur conversion favors microbial community competition and various energy flows from internal polymers (i.e. polysulfide or elemental sulfur (poly-S(2-)/S(0)) and poly-β-hydroxyalkanoates (PHA)) for P removal. If this range was exceeded, the system might deteriorate or even fail due to enrichment of glycogen-accumulating organisms (GAOs). Four methods of restoring the failed system were investigated: increasing the sludge concentration, lowering the salinity or doubling the COD

  6. 东南太平洋热液区硫化物样品富集培养物中Fe3+还原细菌的多样性分析%Diversity analysis of Fe3+ -reducing bacteria in enriched cultures from hydrothermal sulfide sample of southeast Pacific Ocean

    秦丹; 张晓波; 姜丽晶; 盖英宝; 曾湘

    2011-01-01

    采集了东南太平洋热液区DY115-20V-S35-TVG17站位的沉积物硫化物样品,其含有76.717% (m/m)强还原性的磁性良好的黄铁矿.以乳酸钠为电子供体,不溶性的氢氧化铁为电子受体,对该样品进行Fe3+还原细菌的定向富集培养.通过构建该菌群的16S rDNA基因文库,随机挑选82个阳性克隆子进行群落结构多样性分析.研究结果表明:82个克隆代表的6种基因型分别属于4个主要类群,其中ε-变形杆菌占有绝对优势,达到55.2%.此外其还包括厚壁菌门、β-变形杆菌和α-变形杆菌,克隆子比例依次为27.6%、10.3%、6.9%.在富集产物中还原氢氧化铁的功能菌群主要是具有硫还原作用的ε-变形菌中的硫还原菌.%The ocean contains rich resources and in deep sea sediments there exists iron compounds at different stages of oxidation and reduction. Iron is one of the most widely distributed elements on the earth and its cycle chiefly includes two processes of oxidation and reduction. As a primitive form of respiration, Fe3 + -reduction and Fe3 + -reducing bacteria play an important role in the iron cycle where in sediments with an anaerobic environment, where iron chiefly exists in a reduced form. In the current study, a hydrothermal sulfide sample was obtained from the southeast Pacific Ocean, site DY115-20V-S35-TVG17 (50.648 l°N,37.780 2°W, depth 2 783 m) using a television grasp sampler in December, 2008, and was found to be mainly composed of iron pyrite with good magnetism, chiefly Fe1-XS and FeS2, 76.717% (m/m) through X-ray detection. To investigate the diversity of Fe3 +-reducing bacteria in the sample, we designed a medium with sodium lactate as the electron donor and insoluble ferric hydroxide as electron acceptor and cultivated the enriched culture of Fe3 +-reducing bacteria from this sample. The 16S Rdna gene library showed that the 29 selected clones in enriched cultures were clustered into two groups. Pro

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

    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-enrichment in BPW was found to be 0.77 for swine and 0.66 for poultry samples, while a combination...

  8. Culture Studies of Nitrogen and Oxygen Isotope Effects Associated with Nitrate Assimilation and Denitrification

    Sigman, D. M.; Granger, J.; Lehmann, M. F.; Difiore, P. J.; Tortell, P. D.

    2007-12-01

    The isotope effects of nitrate-consuming reactions such as nitrate assimilation and denitrification are potential indicators of the physiological state of the organisms carrying out these reactions. Moreover, an understanding of these isotope effects is needed to use the stable isotopes to investigate the fluxes associated with these reactions in modern and ancient environments. We have used batch cultures to investigate the nitrogen (N) and oxygen (O) isotope effects of (1) nitrate assimilation by eukaryotic and prokaryotic algae and by heterotrophic bacteria, and (2) nitrate reduction by denitrifying bacteria. We observe intra- and inter-specific variation in isotope effect amplitudes and, in the case of denitrifiers, indications of isotope effect decreases during individual nitrate drawdown experiments. However, the measured N and O isotope effect ratio is close to 1 for all studied organisms, with the exception of an unusual denitrifier (Rhodobacter sphaeroides) that possesses only periplasmic (non-respiratory) nitrate reductase. This observation and other findings are consistent with nitrate reductase being the predominant source of isotope fractionation and with most isotope effect amplitude variability arising from variable degrees to which nitrate imported into the cell is reduced versus effluxed back into the environment; the more efflux, the more complete the expression of the fractionation imparted by nitrate reduction. If this is the case, then isotope effect amplitudes in the field should be related to physiological conditions in the environment, a prediction that, we argue, is supported by recent studies of (1) nitrate assimilation in the polar ocean and (2) denitrification in sediment porewaters.

  9. Succession of Denitrifying Community Composition in Coastal Wetland Soils Along a Salinity Gradient

    PIAO Zhe; ZHANG Wen-Wen; MA Shuai; LI Yu-Min; YIN Shi-Xue

    2012-01-01

    To better understand the effect of salinity on denitrification communities,soils along a salinity gradient (ranging from 7.32 to 1.70 mS cm-1) in a wetland along the Yellow Sea coastline in Jiangsu Province,China,were studied using both culture-dependent and -independent methods.Culture efforts yielded 82 isolates in total,81.7% of which were close relatives of Bacillus sp.based on partial sequences of their 16S rRNA genes.Denaturing gradient gel electrophoresis (DGGE) analysis based on 16S rRNA sequences suggested possible existence of bacterial community succession along the salinity gradient.Clone library analysis based on nosZ gene sequences (coding nitrous oxide reductase) showed that operational taxonomic units (OTUs) associated with α-proteobacteria dominated in all three soils,whereas those associated with β-and γ-subdivisions showed a clear succession.In the high salinity soil,only the OTUs associated with α-subdivision were found.In the medium salinity soil,small proportions ofβ- (6.5%) and γ-associated (19.6%) OTUs were found.In the low salinity soil,the proportions were further increased to 33% and 25% for β- and γ-Proteobacteria,respectively.Statistic analysis using Unifrac P test showed that nosZ-communities in different saline soils were significantly different from each other.It could be concluded that α-subdivision of nosZ-community tended to be sustained in high salinity environments whereas β- and γ-subdivisions,especially the former,tended to be sustained in low salinity environments.Salinity was the key determinant of nosZ-community composition in the environment.

  10. Enrichment of light hydrocarbon mixture

    Yang; Dali; Devlin, David; Barbero, Robert S.; Carrera, Martin E.; Colling, Craig W.

    2010-08-10

    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.

  11. Design Enriches Life,Life Breeds Fashion

    Yun Gong

    2016-11-01

    Full Text Available As society advances and technology changes,fashion design has developed from the initial few exclusive to public demand, and fashion category also covers all walks of life, extends to every area from a single demand to industrialization. Fashion design development, has become an indispensable part of people's lives. Fashion satisfies public demand, reflecting the public interest towards, and designer correctly grasp of fashion and taste of popular motivated the design of continuous innovation to creating new business value, cultural values of the social value of fashion. A precise definition to fashion is hard, cause too broad as it relates to areas, such as products, clothing, entertainment, advertising, decoration, home, fashion is reach into every aspect of our lives. Fashion derived from life elements, convergence elements of era and innovation into your life all over again, this cycle forward and updated, fully embodies the understanding of art and life. Design enriches life, life gave birth to fashion.

  12. 31 CFR 540.316 - Uranium enrichment.

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium enrichment. 540.316 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.316 Uranium enrichment. The term uranium enrichment means the process...

  13. Denitratimonas tolerans gen. nov., sp. nov., a denitrifying bacterium isolated from a bioreactor for tannery wastewater treatment.

    Han, Song-Ih; Kim, Ju-Ok; Lee, Ye-Rim; Ekpeghere, Kalu I; Koh, Sung-Cheol; Whang, Kyung-Sook

    2016-06-01

    A denitrifying bacterium, designated strain E4-1(T), was isolated from a bioreactor for tannery wastewater treatment, and its taxonomic position was investigated using a polyphasic approach. Strain E4-1(T), a facultative anaerobic bacterium, was observed to grow between 0 and 12 % (w/v) NaCl, between pH 3.0 and 12.0. Cells were found to be oxidase-positive and catalase-negative. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain E4-1(T) forms a distinct lineage with respect to closely related genera in the family Xanthomonadaceae, and is closely related to Chiayiivirga, Aquimonas and Dokdonella, and the levels of 16S rRNA gene sequence similarity with respect to the type species of related genera are less than 93.9 %. The predominant respiratory quinone was determined to be ubiquinone-8 (Q-8) and the major cellular fatty acids were determined to be iso-C15:0, iso-C17:1 ω9c, iso-C11:0 and iso-C11:0 3OH. Based on physiological, biochemical and chemotaxonomic properties together with results of comparative 16S rRNA gene sequence analysis, strain E4-1(T) is considered to represent a novel species in a new genus, for which the name Denitratimonas tolerans gen. nov., sp. nov. is proposed. The type strain is E4-1(T) (=KACC 17565(T) = NCAIM B 025327(T)).

  14. Effect of dissolved oxygen on nitrate removal using polycaprolactone as an organic carbon source and biofilm carrier in fixed-film denitrifying reactors.

    Luo, Guozhi; Xu, Guimei; Gao, Jinfang; Tan, Hongxin

    2016-05-01

    Nitrate-nitrogen (NO3(-)-N) always accumulates in commercial recirculating aquaculture systems (RASs) with aerobic nitrification units. The ability to reduce NO3(-)-N consistently and confidently could help RASs to become more sustainable. The rich dissolved oxygen (DO) content and sensitive organisms stocked in RASs increase the difficulty of denitrifying technology. A denitrifying process using biologically degradable polymers as an organic carbon source and biofilm carrier was proposed because of its space-efficient nature and strong ability to remove NO3(-)-N from RASs. The effect of dissolved oxygen (DO) levels on heterotrophic denitrification in fixed-film reactors filled with polycaprolactone (PCL) was explored in the current experiment. DO conditions in the influent of the denitrifying reactors were set up as follows: the anoxic treatment group (Group A, average DO concentration of 0.28±0.05mg/L), the low-oxygen treatment DO group (Group B, average DO concentration of 2.50±0.24mg/L) and the aerated treatment group (Group C, average DO concentration of 5.63±0.57mg/L). Feeding with 200mg/L of NO3(-)-N, the NO3(-)-N removal rates were 1.53, 1.60 and 1.42kg/m(3) PCL/day in Groups A, B and C, respectively. No significant difference in NO3(-)-N removal rates was observed among the three treatments. It was concluded that the inhibitory effects of DO concentrations lower than 6mg/L on heterotrophic denitrification in the fixed-film reactors filled with PCL can be mitigated.

  15. Continuous rhamnolipid production using denitrifying Pseudomonas aeruginosa cells in hollow-fiber bioreactor.

    Pinzon, Neissa M; Cook, Aaron G; Ju, Lu-Kwang

    2013-01-01

    Rhamnolipids are high-value effective biosurfactants produced by Pseudomonas aeruginosa. Large-scale production of rhamnolipids is still challenging especially under free-cell aerobic conditions in which the highly foaming nature of the culture broth reduces the productivity of the process. Immobilized systems relying on oxygen as electron acceptor have been previously investigated but oxygen transfer limitation presents difficulties for continuous rhamnolipid production. A coupled system using immobilized cells and nitrate instead of oxygen as electron acceptor taking advantage of the ability of P. aeruginosa to perform nitrate respiration was evaluated. This denitrification-based immobilized approach based on a hollow-fiber setup eliminated the transfer limitation problems and was found suitable for continuous rhamnolipid production in a period longer than 1,500 h. It completely eliminated the foaming difficulties related to aerobic systems with a comparable specific productivity of 0.017 g/(g dry cells)-h and allowed easy recovery of rhamnolipids from the cell-free medium.

  16. Building a Culture of Achievement

    Major, Marc R.

    2009-01-01

    Culture is the social and intergenerational glue that defines, connects, sustains, and enriches the members of successful communities--including schools and classrooms. A classroom culture is a psychological atmosphere that nurtures and shapes students' attitudes about their own identity, classes, school, and learning in general. Classroom culture…

  17. Phylogenetic and functional diversity within toluene-degrading, sulphate-reducing consortia enriched from a contaminated aquifer.

    Kuppardt, Anke; Kleinsteuber, Sabine; Vogt, Carsten; Lüders, Tillmann; Harms, Hauke; Chatzinotas, Antonis

    2014-08-01

    Three toluene-degrading microbial consortia were enriched under sulphate-reducing conditions from different zones of a benzene, toluene, ethylbenzene and xylenes (BTEX) plume of two connected contaminated aquifers. Two cultures were obtained from a weakly contaminated zone of the lower aquifer, while one culture originated from the highly contaminated upper aquifer. We hypothesised that the different habitat characteristics are reflected by distinct degrader populations. Degradation of toluene with concomitant production of sulphide was demonstrated in laboratory microcosms and the enrichment cultures were phylogenetically characterised. The benzylsuccinate synthase alpha-subunit (bssA) marker gene, encoding the enzyme initiating anaerobic toluene degradation, was targeted to characterise the catabolic diversity within the enrichment cultures. It was shown that the hydrogeochemical parameters in the different zones of the plume determined the microbial composition of the enrichment cultures. Both enrichment cultures from the weakly contaminated zone were of a very similar composition, dominated by Deltaproteobacteria with the Desulfobulbaceae (a Desulfopila-related phylotype) as key players. Two different bssA sequence types were found, which were both affiliated to genes from sulphate-reducing Deltaproteobacteria. In contrast, the enrichment culture from the highly contaminated zone was dominated by Clostridia with a Desulfosporosinus-related phylotype as presumed key player. A distinct bssA sequence type with high similarity to other recently detected sequences from clostridial toluene degraders was dominant in this culture. This work contributes to our understanding of the niche partitioning between degrader populations in distinct compartments of BTEX-contaminated aquifers.

  18. Influences of Quinclorac on Culturable Microorganisms and Soil Respiration in Flooded Paddy Soil

    ZHEN-MEI LU; HANG MIN; YANG-FANG YE

    2003-01-01

    Objective To investigate the potential effects of herbicide quinclorac (3,7-dichloro-8-quinoline-carboxylic) on the culturable microorganisms in flooded paddy soil. Methods Total soil aerobic bacteria, actinomycetes and fungi were counted by a 10-fold serial dilution plate technique. Numbers of anaerobic fermentative bacteria (AFB), denitrifying bacteria (DNB) and hydrogen-producing acetogenic bacteria (HPAB) were numerated by three-tube anaerobic most-probable-number (MPN)methods with anaerobic liquid enrichment media. The number of methanogenic bacteria (MB) and nitrogen-fixing bacteria (NFB) was determined by the rolling tube method in triplicate. Soil respiration was monitored by a 102G-type gas chromatography with a stainless steel column filled with GDX-104 and a thermal conductivity detector. Results Quinclorac concentration was an important factor affecting the populations of various culturable microorganisms. There were some significant differences in the aerobic heterotrophic bacteria. AFB and DNB between soils were supplemented with quinclorac and non-quinclorac at the early stage of incubation, but none of them was persistent. The number of fungi and DNB was increased in soil samples treated by lower than1.33 μg·g-1 dried soil, while the CFU of fungi and HPAB was inhibited in soil samples treated by higher than 1.33 μg·g-1 dried soil. The population of actinomycete declined in negative proportion to the concentrations of quinclorac applied after 4 days. However, application of quinclorac greatly stimulated the growth of AFB and NFB. MB was more sensitive to quinclorac than the others, and the three soil samples with concentrations higher than 1 μg·g-1 dried soil declined significantly to less than 40% of that in the control, but the number of samples with lower concentrations of quinclorac was nearly equal to that in the control at the end of experiments. Conclusion Quinclorac is safe to the soil microorganisms when applied at normal

  19. Tissue culture: the unrealized potential

    Sato, Gordon

    2007-01-01

    Lack of differentiated functions of the tissue of origin in tissue culture thought to be due to dedifferentiation was shown to be due to selective overgrowth of fibroblasts. Enrichment culture techniques, (alternate animal and culture passage), designed to give the functionally differentiated cells selective advantage over the fibroblasts resulted in a large number of functionally differentiated clonal strains. Thus the dogma of dedifferentiation was destroyed. It is proposed to substitute th...

  20. Biomedical advances from tissue culture

    Okamoto, Tetsuji; Sato, J. Denry; Barnes, David W.; Sato, Gordon H.

    2013-01-01

    The demonstration that the “dedifferentiation” of cells commonly observed in the early days of tissue culture was due to selective overgrowth of fibroblasts led to enrichment culture techniques (alternate animal and culture passage) designed to give a selective advantage to functionally differentiated tumor cells. These experiments resulted in the derivation of a large number of functionally differentiated clonal strains of a range of cell types. These results gave rise to the hypothesis that...

  1. Impact of electro-stimulation on denitrifying bacterial growth and analysis of bacterial growth kinetics using a modified Gompertz model in a bio-electrochemical denitrification reactor.

    Liu, Hengyuan; Chen, Nan; Feng, Chuanping; Tong, Shuang; Li, Rui

    2017-05-01

    This study aimed to investigate the effect of electro-stimulation on denitrifying bacterial growth in a bio-electrochemical reactor, and the growth were modeled using modified Gompertz model under different current densities at three C/Ns. It was found that the similar optimum current density of 250mA/m(2) was obtained at C/N=0.75, 1.00 and 1.25, correspondingly the maximum nitrate removal efficiencies were 98.0%, 99.2% and 99.9%. Moreover, ATP content and cell membrane permeability of denitrifying bacteria were significantly increased at optimum current density. Furthermore, modified Gompertz model fitted well with the microbial growth curves, and the highest maximum growth rates (µmax) and shorter lag time were obtained at the optimum current density for all C/Ns. This study demonstrated that the modified Gompertz model could be used for describing microbial growth under different current densities and C/Ns in a bio-electrochemical denitrification reactor, and it provided an alternative for improving the performance of denitrification process.

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

    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 YA=2.3465 mg O2 mg N(-1), μm, A=0.7169 h(-1), and KNH=2.0748 mg NL(-1).

  3. Enrichment of lanthanides in aragonite

    瞿成利; 路波; 刘刚

    2009-01-01

    Using the constant addition technique,the coprecipitation of lanthanum,gadolinium,and lutetium with aragonite in seawater was experimentally investigated at 25 ℃.Their concentrations in aragonite overgrowths were determined by inductive coupled plasma mass spectrometer.All these lanthanides were strongly enriched in aragonite overgrowths.The amount of lanthanum,gadolinium,and lutetium incorporated into aragonite accounted for 57%-99%,50%-89%,and 40%-91% of their initial total amount,respectively.With the in...

  4. Resource recovery from organic waste streams by microbial enrichment cultures

    Tamis, J.

    2015-01-01

    Polyhydroxyalkanoate (PHA) is a natural product that can potentially replace a part of the chemicals and plastics derived from fossil sources. One of the main barriers for market entry of PHA is its relatively high price compared to conventional (fossil) feedstocks. This high price is related to cur

  5. Cultural Enrichment: Connecting African American Elementary Children to Academic Achievement

    Winston, Deborah L.

    2011-01-01

    A large, growing number of mis-educated American citizens are being produced by America's public schools. Many of these students are being funneled into the penal system shortly after dropping out of high school. This phenomenon is especially prevalent among African American male students, many of whom have withdrawn academically years prior…

  6. Enrichment and aggression in primates.

    Honess, P E; Marin, C M

    2006-01-01

    There is considerable evidence that primates housed under impoverished conditions develop behavioural abnormalities, including, in the most extreme example, self-harming behaviour. This has implications for all contexts in which primates are maintained in captivity from laboratories to zoos since by compromising the animals' psychological well-being and allowing them to develop behavioural abnormalities their value as appropriate educational and research models is diminished. This review examines the extensive body of literature documenting attempts to improve living conditions with a view to correcting behavioural abnormalities and housing primates in such a way that they are encouraged to exhibit a more natural range and proportion of behaviours, including less self-directed and social aggression. The results of housing, feeding, physical, sensory and social enrichment efforts are examined with specific focus on their effect on aggressive behaviour and variation in their use and efficacy. It is concluded that while inappropriate or poorly distributed enrichment may encourage aggressive competition, enrichment that is species, sex, age and background appropriate can dramatically reduce aggression, can eliminate abnormal behaviour and substantially improve the welfare of primates maintained in captivity.

  7. Nitrogen removal and spatial distribution of denitrifier and anammox communities in a bioreactor for mine drainage treatment.

    Herbert, Roger B; Winbjörk, Harry; Hellman, Maria; Hallin, Sara

    2014-12-01

    Mine drainage water may contain high levels of nitrate (NO3(-)) due to undetonated nitrogen-based explosives. The removal of NO3(-) and nitrite (NO2(-)) in cold climates through the microbial process of denitrification was evaluated using a pilot-scale fixed-bed bioreactor (27 m(3)). Surface water was diverted into the above-ground bioreactor filled with sawdust, crushed rock, and sewage sludge. At hydraulic residence times of ca.15 h and with the addition of acetate, NO3(-) and NO2(-) were removed to below detection levels at a NO3(-) removal rate of 5-10 g N m(-3) (bioreactor material) d(-1). The functional groups contributing to nitrogen removal in the bioreactor were studied by quantifying nirS and nirK present in denitrifying bacteria, nosZI and nosZII genes from the nitrous oxide - reducing community, and a taxa-specific part of the16S rRNA gene for the anammox community. The abundances of nirS and nirK were almost 2 orders of magnitude greater than the anammox specific 16S rRNA gene, indicating that denitrification was the main process involved in nitrogen removal. The spatial distribution of the quantified genes was heterogeneous in the bioreactor, with trends observed in gene abundance as a function of depth, distance from the bioreactor inlet, and along specific flowpaths. There was a significant relationship between the abundance of nirS, nirK, and nosZI genes and depth in the bioreactor, such that the abundance of organisms containing these genes may be controlled by oxygen diffusion and substrate supply in the partially or completely water-saturated material. Among the investigated microbial functional groups, nirS and anammox bacterial 16S rRNA genes exhibited a systematic trend of decreasing and increasing abundance, respectively, with distance from the inlet, which suggested that the functional groups respond differently to changing environmental conditions. The greater abundance of nirK along central flowpaths may indicate that the bioreactor

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

    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.

  9. Selective Enrichment of a Methanol-Utilizing Consortium Using Pulp and Paper Mill Waste Streams

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

    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. Wasteactivated 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 4 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-h 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.

  10. 亚硝化-反硝化除磷技术研究进展%Advance of Research on the Technology of Nitrite-denitrifying Phosphorus Removal

    叶丽红; 李冬; 张杰; 张金库; 曾辉平

    2016-01-01

    With nitrogen and phosphorus in water body caused the environmental problem, removal of the nitrogen and phosphorus in water body with low cost has become a challenge to the biological wastewater treatment worldwide. The technology of nitrite-denitrifying phosphorus removal has advantages of reducing carbon source consumption, saving occupied area, improving water treatment equipment utilization, and decreasing sludge production. But it remains unclear about the cognition of phosphorus accumulating organisms( PAOs) , and the stable operation of the whole technology that ammonia is reduced to nitrite and denitrifying phosphorus removal is not reported at present. Simultaneously, according to different researchers, PAOs has different classification, while the main results of the mechanism with short-cut denitrifying phosphorus removal are phosphate release and storage energy in anaerobic, then the energy supply for denitrifying phosphorus uptake with nitrite as the electron acceptor in anoxic. The effect of nitrogen and phosphorus removal is influenced by temperature, pH, the kind of carbon source, the value of ρ(C)/ρ(P) and other factors, so, in order to achieve the stable and efficient treatment of sewage wastewater, the reaction conditions of short-cut denitrifying phosphorus removal is necessarily reasonable. It is necessary to summerize the relevant research reported on the nitrite-denitrification and phosphorus removal to guide and overcome the disadvantages of the biological nitrogen and phosphorus removal.%氮磷引起的环境问题已引起世界关注,低成本减少水体氮磷污染是生物处理工艺面临的挑战。亚硝化-反硝化除磷工艺具有节约碳源和能源、节省空间及占地、提高水处理设备利用率、减少污泥产量等优势,但关于聚磷菌( PAOs)的认知缺乏深入了解,且目前尚未见氨氮亚硝化-反亚硝酸除磷整体工艺的稳定运行报道。关于PAOs的分类,不同研究者有不

  11. Network-based functional enrichment

    Poirel Christopher L

    2011-11-01

    Full Text Available Abstract Background Many methods have been developed to infer and reason about molecular interaction networks. These approaches often yield networks with hundreds or thousands of nodes and up to an order of magnitude more edges. It is often desirable to summarize the biological information in such networks. A very common approach is to use gene function enrichment analysis for this task. A major drawback of this method is that it ignores information about the edges in the network being analyzed, i.e., it treats the network simply as a set of genes. In this paper, we introduce a novel method for functional enrichment that explicitly takes network interactions into account. Results Our approach naturally generalizes Fisher’s exact test, a gene set-based technique. Given a function of interest, we compute the subgraph of the network induced by genes annotated to this function. We use the sequence of sizes of the connected components of this sub-network to estimate its connectivity. We estimate the statistical significance of the connectivity empirically by a permutation test. We present three applications of our method: i determine which functions are enriched in a given network, ii given a network and an interesting sub-network of genes within that network, determine which functions are enriched in the sub-network, and iii given two networks, determine the functions for which the connectivity improves when we merge the second network into the first. Through these applications, we show that our approach is a natural alternative to network clustering algorithms. Conclusions We presented a novel approach to functional enrichment that takes into account the pairwise relationships among genes annotated by a particular function. Each of the three applications discovers highly relevant functions. We used our methods to study biological data from three different organisms. Our results demonstrate the wide applicability of our methods. Our algorithms are

  12. NEAT: an efficient network enrichment analysis test

    Signorelli, Mirko; Vinciotti, Veronica; Wit, Ernst C

    2016-01-01

    Background Network enrichment analysis is a powerful method, which allows to integrate gene enrichment analysis with the information on relationships between genes that is provided by gene networks. Existing tests for network enrichment analysis deal only with undirected networks, they can be computationally slow and are based on normality assumptions. Results We propose NEAT, a test for network enrichment analysis. The test is based on the hypergeometric distribution, which naturally arises ...

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

    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

  14. Enriching Music and Language Arts Experiences

    Flohr, John W.

    2006-01-01

    The article focuses on enriching music and language arts experiences of students. Music can enrich literature and language arts, poetry, theater arts, transitions, science, and math, as well as help meet special learner needs. A well-understood example of enrichment is the alphabet song. A music or classroom teacher using the alphabet song helps…

  15. How Did the IGM Become Enriched?

    Aguirre, A; 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.

  16. Characterization of nitrate-reducing and amino acid-using bacteria prominent in nitrotoxin-enriched equine cecal populations

    In the present study, populations of equine cecal microbes enriched for enhanced rates of 3-nitro-1-propionic acid (NPA) or nitrate metabolism were diluted and cultured for NPA-metabolizing bacteria on a basal enrichment medium (BEM) or tryptose soy agar (TSA) medium supplemented with either 5 mM NP...

  17. Enrichment planting without soil treatment

    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

  18. Boron enrichment in martian clay.

    James D Stephenson

    Full Text Available We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration.

  19. Environmental enrichment for primates in laboratories

    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.

  20. Cultivation of Denitrifying Polyphosphate-accumulating Organisms in Sequencing Batch Reactor%SBR反应器中反硝化除磷菌的快速富集

    夏灵敏; 王弘宇; 田俊; 杨开; 张静

    2013-01-01

    Denitrifying polyphosphate-accumulating organisms (DPAOs),a principal part in the denitrifying phosphorus removal process,can remove nitrogen and phosphorus simultaneously under anoxic condition.The cultivation of DPAOs was achieved in a two-stage sequencing batch reactor (SBR) system,using the returned sludge from a secondary settling tank of Wuhan Shahu WWTP.The first-stage SBR operated in anaerobic/aerobic (A/O) mode to achieve the cultivation of PAOs.After 13 d,the removal rates of nitrogen and phosphorus were all above 85%.The second-stage SBR operated in anaerobic/aerobic/anoxic (A/O/A) mode to achieve the cultivation of DPAOs.After 26 d,the removal rates of ammonia nitrogen and phosphate were 92.2% and 91.2%,respectively.There was a linear relationship between phosphorus uptake and nitrate consumption,which suggested that the denitrifying phosphorus removal ability of the system was enhanced significantly.%反硝化除磷菌(DPAOs)能够在缺氧条件下同步完成脱氮除磷,是反硝化除磷工艺的主体.以武汉沙湖污水处理厂二沉池的回流污泥为种泥,采用二段式SBR工艺实现了反硝化除磷菌的快速富集.在第一阶段反应器采用厌氧/好氧(A/O)模式运行,可以实现对除磷菌(PAOs)的快速诱导和富集,运行13d后,SBR反应器对氮、磷的去除率均达到85%以上.而后进入第二阶段,采用厌氧/好氧/缺氧(A/O/A)模式运行,以快速富集培养反硝化除磷菌,经过26 d的运行,反应器对氨氮和磷酸盐的去除率分别达到92.2%和91.2%左右,且典型周期内硝酸盐的消耗量与磷的吸收量基本呈线性关系,表明系统的反硝化除磷能力得到显著增强.

  1. Trace elements affect methanogenic activity and diversity in enrichments from subsurface coal bed produced water.

    Unal, Burcu; Perry, Verlin Ryan; Sheth, Mili; Gomez-Alvarez, Vicente; Chin, Kuk-Jeong; Nüsslein, Klaus

    2012-01-01

    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 (CBM) 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 7 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 (R(2) = 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 CBM production and alter the composition of the active methanogenic community.

  2. Trace elements affect methanogenic activity and diversity in enrichments from subsurface coal bed produced water

    Burcu eÜnal

    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

  3. Degradation of toluene by a mixed population of archetypal aerobes, microaerophiles, and denitrifiers: laboratory sand column experiment and multispecies biofilm model formulation.

    Kim, Hyun-Su; Jaffé, Peter R

    2008-02-01

    An experiment was conducted in a saturated sand column with three bacterial strains that have different growth characteristics on toluene, Pseudomonas putida F1 which degrades toluene only under aerobic conditions, Thauera aromatica T1 which degrades toluene only under denitrifying conditions, and Ralstonia pickettii PKO1 has a facultative nature and can perform nitrate-enhanced biodegradation of toluene under hypoxic conditions (DO <2 mg/L). Steady-state concentration profiles showed that oxygen and nitrate appeared to be utilized simultaneously, regardless of the dissolved oxygen concentration and the results from fluorescent in-situ hybridization (FISH) indicated that PKO1 maintained stable cells numbers throughout the column, even when the pore water oxygen concentration was high. Since PKO1's growth rate under aerobic condition is much lower than that of F1, except under hypoxic conditions, these observations were not anticipated. Therefore these observations require a mechanistic explanation that can account for localized low oxygen concentrations under aerobic conditions. To simulate the observed dynamics, a multispecies biofilm model was implemented. This model formulation assumes the formation of a thin biofilm that is composed of the three bacterial strains. The individual strains grow in response to the substrate and electron acceptor flux from bulk fluid into the biofilm. The model was implemented such that internal changes in bacterial composition and substrate concentration can be simulated over time and space. The model simulations from oxic to denitrifying conditions compared well to the experimental profiles of the chemical species and the bacterial strains, indicating the importance of accounting for the biological activity of individual strains in biofilms that span different redox conditions.

  4. Detoxification of tar water by anaerobic treatment in an UASB reactor - A study of the degradation of phenolic compounds in a combined denitrifying and anaerobic UASB reactor

    Skibsted Mogensen, A.; Schmidt, J.E.; Ahring, B.K. [Technical Univ., Dept. of Environmental Science and Engineering, Lyngby (Denmark)

    1998-08-01

    The digestion of pyrolysis condensate (PC) in two combined anaerobic and denitrifying upflow anaerobic sludge blanket (UASB) reactors was studied. A COD removal of 80% was achieved with an influent concentration of 1.43% PC{sub pH}. When the reactor was fed with 100% PC during a period of 10 days good reactor operation was observed. Despite less than one retention time of operation, the results indicated clearly, that PC could be used as substrate in the biogas process, even in very high concentrations. A combined anaerobic and denitrifying UASB reactor was successfully digesting 5.5% of wet oxidised PC, but further loading increments deteriorated the anaerobic digestion process. The detoxification of PC was studied by determining the degradation of phenols during reactor operation and the toxicity of PC was decreased more than 77 times witnessed through decreased inhibition of the nitrification process. Phenol, methyl and dimethyl phenols along with methoxyphenols were shown to be degraded within the reactor systems. Degradation rates for phenol and substituted phenols were determined by the reactor experiment indicating that the biomass was selective towards the substrates. Maximum growth rates and half saturation constants for phenol, 4-Methylphenol and 2-Methoxy-4-methylphenol were determined in batch experiments. The degradation rates of phenols determined in batches were significantly higher compared to degradation rates observed in the reactor systems digesting pyrolysis condensate. Determination of the population of methanogens revealed, that Methanosarcina was found only in one reactor, while Methanobacterium and Methanosaeta were found in reactors and inoculum. A UASB reactor was designed for the treatment of pyrolysis condensate at the gasification plant at Harbooere, Denmark. (au) 35 refs.

  5. Tibet Policies Enrich Region's Development

    2007-01-01

    During an interview with the German magazine Der Spiegel published on March 26,the 14th Dalai Lama attacked the Chinese government as"dividing Tibet by letting other provinces govern parts of Tibet".He also claimed that Tibet was"suffering cultural homicide".

  6. Early stationary phase culture supernatant accelerates growth of sputum cultures collected after initiation of anti-tuberculosis treatment.

    Kolwijck, E; Friedrich, S O; Karinja, M N; van Ingen, J; Warren, R M; Diacon, A H

    2014-07-01

    We investigated the effect of Mycobacterium tuberculosis culture supernatant added to sputum cultures collected during the first 8 weeks of anti-tuberculosis treatment. With ongoing treatment duration, time to culture positivity decreased significantly in supernatant-enriched cultures, possibly due to stimulation of dormant or slowly metabolizing M. tuberculosis cells.

  7. Environmental enrichment in farm, zoo, companion and experimental animals

    Vučinić Marijana

    2009-01-01

    Full Text Available The paper deals with environmental enrichment for domestic animals at farms, animals in zoos, experimental animals and pet animals. Also, the paper defines and describes different strategies of environmental enrichment. Environmental enrichment is a simple and effective mean of prevention of boredom, behavioral disorders as well as an effective mean of improving animal welfare in farm, zoo, companion and experimental animals. Different items and materials may be used for environmental enrichment. They need to be evaluated for use by taking into account the following: the species of an animal, its needs, habits and capabilities, the type of an enrichment device, the device's ability to stimulate the animal's interest and the safety of the device. Enrichment programmes should always include two forms of enrichment: behavioral enrichment and environmental enrichment. Enrichment comes in many forms such as structural or physical enrichment, sensory enrichment (auditory and olfactory stimulation, dietary enrichment, manipulatable enrichment and social enrichment.

  8. Enrichment and characteristics of mixed methane-oxidizing bacteria from a Chinese coal mine.

    Jiang, Hao; Duan, Changhong; Luo, Mingfang; Xing, Xin-Hui

    2016-12-01

    In methane-rich environments, methane-oxidizing bacteria usually occur predominantly among consortia including other types of microorganisms. In this study, artificial coal bed gas and methane gas were used to enrich mixed methanotrophic cultures from the soil of a coal mine in China, respectively. The changes in microbial community structure and function during the enrichment were examined. The microbial diversity was reduced as the enrichment proceeded, while the capacity for methane oxidation was significantly enhanced by the increased abundance of methanotrophs. The proportion of type II methanotrophs increased greatly from 7.84 % in the sampled soil to about 50 % in the enrichment cultures, due to the increase of methane concentration. After the microbial community of the cultures got stable, Methylomonas and Methylocystis became the dominant type I and type II methanotrophs, while Methylophilus was the prevailing methylotroph. The sequences affiliated with pigment-producing strains, Methylomonas rubra, Hydrogenophaga sp. AH-24, and Flavobacterium cucumis, could explain the orange appearance of the cultures. Comparing the two cultures, the multi-carbon sources in the artificial coal bed gas caused more variety of non-methanotrophic bacteria, but did not help to maintain the diversity or to increase the quantity and activity of methanotrophs. The results could help to understand the succession and interaction of microbial community in a methane-driven ecosystem.

  9. Student science enrichment training program

    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.

  10. 21 CFR 137.350 - Enriched rice.

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Enriched rice. 137.350 Section 137.350 Food and... Related Products § 137.350 Enriched rice. (a) The foods for which definitions and standards of identity are prescribed by this section are forms of milled rice (except rice coated with talc and glucose...

  11. A Component Analysis of Marriage Enrichment.

    Buston, Beverley G.; And Others

    Although marriage enrichment programs have been shown to be effective for many couples, a multidimensional approach to assessment is needed in investigating these groups. The components of information and social support in successful marriage enrichment programs were compared in a completely crossed 2 x 2 factorial design with repeated measures.…

  12. Inoculation Stress Hypothesis of Environmental Enrichment

    Crofton, Elizabeth J.; Zhang, Yafang; Green, Thomas A.

    2014-01-01

    One hallmark of psychiatric conditions is the vast continuum of individual differences in susceptibility vs. resilience resulting from the interaction of genetic and environmental factors. The environmental enrichment paradigm is an animal model that is useful for studying a range of psychiatric conditions, including protective phenotypes in addiction and depression models. The major question is how environmental enrichment, a non-drug and non-surgical manipulation, can produce such robust individual differences in such a wide range of behaviors. This paper draws from a variety of published sources to outline a coherent hypothesis of inoculation stress as a factor producing the protective enrichment phenotypes. The basic tenet suggests that chronic mild stress from living in a complex environment and interacting non-aggressively with conspecifics can inoculate enriched rats against subsequent stressors and/or drugs of abuse. This paper reviews the enrichment phenotypes, mulls the fundamental nature of environmental enrichment vs. isolation, discusses the most appropriate control for environmental enrichment, and challenges the idea that cortisol/corticosterone equals stress. The intent of the inoculation stress hypothesis of environmental enrichment is to provide a scaffold with which to build testable hypotheses for the elucidation of the molecular mechanisms underlying these protective phenotypes and thus provide new therapeutic targets to treat psychiatric/neurological conditions. PMID:25449533

  13. Enrichment-ELISA for Detection of Salmonella typhi From Food and Water Samples

    S.KUMAR; K.BALAKRISHNA; HV.BATRA

    2008-01-01

    Objective Development of monoclonal antibody based sandwich enzyme linked immunosorbant assay(sELISA)for rapid detection of Salmonella enterica serovar typhi(S.typhi) from food and water samples and optimization of enrichment procedures for use with the developed sELISA to increase the detection Sensitivity of the assay. Methods Spleen cells from BALB/c mice immunized with flagellin(H=d)antigen of S.typhi were fused with Sp2/0 myeloma cells.The hybridoma cell line specific to H=d antigen was established.characterized and ascites raised against one of these clones.The hypefimmune serum to flagellin antigen was raised in New Zealand White rabbits.An sELISA was developed using polyclonalantibody as capture and monoelonal antibody as detection antibody.To design the efficient culture sUrategies for use with the sELISA.different pre-enrichment and enrichment brothswere evaluated.The mediaincluded buffered peptonewater(BPW)and brain heart infusion broth for pre-enrichment and selenite F broth and Rappaport-Vassiliadis broth as enrichment broths.The developed sELISA with preceding enrichment step in BPW(Enrichment-ELISA)was evaluated in various food samples artificially inoculated with S. typhi bacteria.Various food(30)and water(35)samples collected from field were also tested by Enrichment-ELISA and culture method. Results Out of four specific clones to H=d antigen,one clone(#2/56.IgG2a isotype)was usedin sELISA.The sELISA had the detectionlimit of 104-105 cfu of S.typhi.Of the various broths used with sELISA,BPW was found to yield maximum ELISA values.Enrichment-ELISA,when tested in artificially inoculated food samples,generally,could detect 102S.typhi cfu/mL within 10 h from variousfood rinses(meat,vegetable)and milk samples.After overnight enrichment in BPW,as less as 2 bacteria per 10 mL of milk,meat rinse.and chicken rinse could be detected.Only one of the field samples(water)gave false positive result by Enrichment-ELISA.Conclusion In comparison to culture

  14. Neuron enriched nuclear proteome isolated from human brain.

    Dammer, Eric B; Duong, Duc M; Diner, Ian; Gearing, Marla; Feng, Yue; Lah, James J; Levey, Allan I; Seyfried, Nicholas T

    2013-07-05

    The brain consists of diverse cell types including neurons, astrocytes, oligodendrocytes, and microglia. The isolation of nuclei from these distinct cell populations provides an opportunity to identify cell-type-specific nuclear proteins, histone modifications, and regulation networks that are altered with normal brain aging or neurodegenerative disease. In this study, we used a method by which intact neuronal and non-neuronal nuclei were purified from human post-mortem brain employing a modification of fluorescence activated cell sorting (FACS) termed fluorescence activated nuclei sorting (FANS). An antibody against NeuN, a neuron specific splicing factor, was used to isolate neuronal nuclei. Utilizing mass spectrometry (MS) based label-free quantitative proteomics, we identified 1755 proteins from sorted NeuN-positive and negative nuclear extracts. Approximately 20% of these proteins were significantly enriched or depleted in neuronal versus non-neuronal populations. Immunoblots of primary cultured rat neuron, astrocyte, and oligodendrocyte extracts confirmed that distinct members of the major nucleocytoplasmic structural linkage complex (LINC), nesprin-1 and nesprin-3, were differentially enriched in neurons and astrocytes, respectively. These comparative proteomic data sets also reveal a number of transcription and splicing factors that are selectively enriched in a cell-type-specific manner in human brain.

  15. Enriching an effect calculus with linear types

    Egger, Jeff; Møgelberg, Rasmus Ejlers; Simpson, Alex

    2009-01-01

    We define an ``enriched effect calculus'' by conservatively extending  a type theory for computational effects with primitives from linear logic. By doing so, we obtain a generalisation of linear type theory, intended as a formalism for expressing linear aspects of effects. As a worked example, we...... formulate  linearly-used continuations in the enriched effect calculus. These are captured by a fundamental translation of the enriched effect calculus into itself, which extends existing call-by-value and call-by-name linearly-used CPS translations. We show that our translation is involutive. Full...... completeness results for the various linearly-used CPS translations  follow. Our main results, the conservativity of enriching the effect calculus with linear primitives, and the involution property of the fundamental translation, are proved using a category-theoretic semantics for the enriched effect calculus...

  16. Ethyl tert-butyl ether (ETBE)-degrading microbial communities in enrichments from polluted environments.

    Le Digabel, Yoann; Demanèche, Sandrine; Benoit, Yves; Fayolle-Guichard, Françoise; Vogel, Timothy M

    2014-08-30

    The ethyl tert-butyl ether (ETBE) degradation capacity and phylogenetic composition of five aerobic enrichment cultures with ETBE as the sole carbon and energy source were studied. In all cases, ETBE was entirely degraded to biomass and CO2. Clone libraries of the 16S rRNA gene were prepared from each enrichment. The analyses of the DNA sequences obtained showed different taxonomic compositions with a majority of Proteobacteria in three cases. The two other enrichments have different microbiota with an abundance of Acidobacteria in one case, whereas the microbiota in the second was more diverse (majority of Actinobacteria, Chlorobi and Gemmatimonadetes). Actinobacteria were detected in all five enrichments. Several bacterial strains were isolated from the enrichments and five were capable of degrading ETBE and/or tert-butyl alcohol (TBA), a degradation intermediate. The five included three Rhodococcus sp. (IFP 2040, IFP 2041, IFP 2043), one Betaproteobacteria (IFP 2047) belonging to the Rubrivivax/Leptothrix/Ideonella branch, and one Pseudonocardia sp. (IFP 2050). Quantification of these five strains and two other strains, Rhodococcus sp. IFP 2042 and Bradyrhizobium sp. IFP2049, which had been previously isolated from one of the enrichments was carried out on the different enrichments based on quantitative PCR with specific 16S rRNA gene primers and the results were consistent with the hypothesized role of Actinobacteria and Betaproteobacteria in the degradation of ETBE and the possible role of Bradyrhizobium strains in the degradation of TBA.

  17. Fluxes in PHA-storing microbial communities during enrichment and biopolymer accumulation processes.

    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.

  18. Deuterium enrichment of interstellar dusts

    Das, Ankan; Chakrabarti, Sandip Kumar; Majumdar, Liton; Sahu, Dipen

    2016-07-01

    High abundance of some abundant and simple interstellar species could be explained by considering the chemistry that occurs on interstellar dusts. Because of its simplicity, the rate equation method is widely used to study the surface chemistry. However, because the recombination efficiency for the formation of any surface species is highly dependent on various physical and chemical parameters, the Monte Carlo method is best suited for addressing the randomness of the processes. We carry out Monte-Carlo simulation to study deuterium enrichment of interstellar grain mantle under various physical conditions. Based on the physical properties, various types of clouds are considered. We find that in diffuse cloud regions, very strong radiation fields persists and hardly a few layers of surface species are formed. In translucent cloud regions with a moderate radiation field, significant number of layers would be produced and surface coverage is mainly dominated by photo-dissociation products such as, C, CH_3, CH_2D, OH and OD. In the intermediate dense cloud regions (having number density of total hydrogen nuclei in all forms ˜2 × 10^4 cm^{-3}), water and methanol along with their deuterated derivatives are efficiently formed. For much higher density regions (˜10^6 cm^{-3}), water and methanol productions are suppressed but surface coverage of CO, CO_2, O_2, O_3 are dramatically increased. We find a very high degree of fractionation of water and methanol. Observational results support a high fractionation of methanol but surprisingly water fractionation is found to be low. This is in contradiction with our model results indicating alternative routes for de-fractionation of water.

  19. Profile of World Uranium Enrichment Programs-2009

    Laughter, Mark D [ORNL

    2009-04-01

    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

  20. Nitrous Oxide Emission and Denitrifier Abundance in Two Agricultural Soils Amended with Crop Residues and Urea in the North China Plain

    Jin, Haiyang; Liu, Yuan; Bai, Xueying; Ma, Dongyun; Zhu, Yunji; Wang, Chenyang; Guo, Tiancai

    2016-01-01

    The application of crop residues combined with Nitrogen (N) fertilizer has been broadly adopted in China. Crop residue amendments can provide readily available C and N, as well as other nutrients to agricultural soils, but also intensify the N fixation, further affecting N2O emissions. N2O pulses are obviously driven by rainfall, irrigation and fertilization. Fertilization before rainfall or followed by flooding irrigation is a general management practice for a wheat-maize rotation in the North China Plain. Yet, little is known on the impacts of crop residues combined with N fertilizer application on N2O emission under high soil moisture content. A laboratory incubation experiment was conducted to investigate the effects of two crop residue amendments (maize and wheat), individually or in combination with N fertilizer, on N2O emissions and denitrifier abundance in two main agricultural soils (one is an alluvial soil, pH 8.55, belongs to Ochri-Aquic Cambosols, OAC, the other is a lime concretion black soil, pH 6.61, belongs to Hapli-Aquic Vertosols, HAV) under 80% WFPS (the water filled pore space) in the North China Plain. Each type soil contains seven treatments: a control with no N fertilizer application (CK, N0), 200 kg N ha-1 (N200), 250 kg N ha-1 (N250), maize residue plus N200 (MN200), maize residue plus N250 (MN250), wheat residue plus N200 (WN200) and wheat residue plus N250 (WN250). Results showed that, in the HAV soil, MN250 and WN250 increased the cumulative N2O emissions by 60% and 30% compared with N250 treatment, respectively, but MN200 and WN200 decreased the cumulative N2O emissions by 20% and 50% compared with N200. In the OAC soil, compared with N200 or N250, WN200 and WN250 increased the cumulative N2O emission by 40%-50%, but MN200 and MN250 decreased the cumulative N2O emission by 10%-20%. Compared with CK, addition of crop residue or N fertilizer resulted in significant increases in N2O emissions in both soils. The cumulative N2O emissions

  1. Nitrous Oxide Emission and Denitrifier Abundance in Two Agricultural Soils Amended with Crop Residues and Urea in the North China Plain.

    Jianmin Gao

    Full Text Available The application of crop residues combined with Nitrogen (N fertilizer has been broadly adopted in China. Crop residue amendments can provide readily available C and N, as well as other nutrients to agricultural soils, but also intensify the N fixation, further affecting N2O emissions. N2O pulses are obviously driven by rainfall, irrigation and fertilization. Fertilization before rainfall or followed by flooding irrigation is a general management practice for a wheat-maize rotation in the North China Plain. Yet, little is known on the impacts of crop residues combined with N fertilizer application on N2O emission under high soil moisture content. A laboratory incubation experiment was conducted to investigate the effects of two crop residue amendments (maize and wheat, individually or in combination with N fertilizer, on N2O emissions and denitrifier abundance in two main agricultural soils (one is an alluvial soil, pH 8.55, belongs to Ochri-Aquic Cambosols, OAC, the other is a lime concretion black soil, pH 6.61, belongs to Hapli-Aquic Vertosols, HAV under 80% WFPS (the water filled pore space in the North China Plain. Each type soil contains seven treatments: a control with no N fertilizer application (CK, N0, 200 kg N ha-1 (N200, 250 kg N ha-1 (N250, maize residue plus N200 (MN200, maize residue plus N250 (MN250, wheat residue plus N200 (WN200 and wheat residue plus N250 (WN250. Results showed that, in the HAV soil, MN250 and WN250 increased the cumulative N2O emissions by 60% and 30% compared with N250 treatment, respectively, but MN200 and WN200 decreased the cumulative N2O emissions by 20% and 50% compared with N200. In the OAC soil, compared with N200 or N250, WN200 and WN250 increased the cumulative N2O emission by 40%-50%, but MN200 and MN250 decreased the cumulative N2O emission by 10%-20%. Compared with CK, addition of crop residue or N fertilizer resulted in significant increases in N2O emissions in both soils. The cumulative N2O

  2. Enhancing effect of induced crystallization process on denitrifying phosphorus removal%诱导结晶对反硝化除磷的强化作用

    顾倩; 吕锡武; 史静; 李洁

    2013-01-01

    To investigate the enhancing effect of induced crystallization on the denitrifying phosphorus removal,experiments were carried out by combining the two-sludge system and the induced crystallization process.The results show that the phosphorus recovery rate of induced crystallizer is not greatly improved when the mole ratio of n(Ca2+)/n(PO43--P) reaches 5∶1.The optimum value of n (Ca2 +)/n (PO43--P) is 3∶1 which achieves a phosphorus recovery rate of 62.05 %.Appropriately increasing the amount of phosphorus recovery does not have a significant effect on the amount of anaerobic phosphorus release.When the amount of phosphorus release maintains at (13.44 ± 0.55)mg/L,the amount of phosphorus uptake decreases from 21.11 to 16.42 mg/L.The ratio of phosphorus uptake amount to release amount falls from 1.51 to 1.24 along with a high recovery rate,which means that the burden of bio-P removal is lightened.During the prior period of denitrifying phosphorus removal,the rate of phosphorus uptake goes down while the amount of phosphorus recovery increases,but the reaction of denitrifying phosphorus removal all ends after 30 min.Chemical phosphorus recovery do not cause negative effect on biological phosphorus removal.Moreover,the process which combines biological phosphorus removal with chemical phosphorus recovery can ensure that the effluent quality meets the related requirements under the condition of low influent CODto-phosphorus mass ratio.%以双污泥-诱导结晶工艺为研究对象,考察诱导结晶工艺回收磷对反硝化除磷的强化作用.结果表明,当摩尔比n(Ca2+)/n(PO43--P)提高到5∶1时,反应器内回收率没有明显的提高,最佳n(Ca2+)/n(PO43--P)为3∶1,回收率可达62.05%;提高磷回收量对厌氧释磷影响并不大,当释磷量保持在(13.44±0.55) mg/L时,聚磷量由21.11 mg/L降至16.42 mg/L,聚磷量与释磷量之比从1.51降至1.24,化学回收磷减轻了生物除磷负担;提高结晶磷回收量会降低聚磷

  3. Selective enrichment of Geobacter sulfurreducens from anaerobic granular sludge with quinones as terminal electron acceptors

    Cervantes-Carillo, F.J.; Duong Dac, T.; Ivanova, A.E.; Roest, de K.; Akkermans, A.D.L.; Lettinga, G.; Field, J.A.

    2003-01-01

    A quinone-respiring, enrichment culture derived from methanogenic granular sludge was phylogenetically characterized by using a combined cloning-denaturing gradient gel electrophoresis (DGGE) method, which revealed that the consortium developed was dominated by a single microorganism: 97% related, i

  4. Teaching and Learning Culture

    inside and outside the classroom; at the same time, culture also influences the context of the learning. The context may be “invisible” and hide itself as tacit knowledge or embedded values, or it may be very visible and present itself as a fixed curriculum or an established tradition. No matter what......, including a student-centered task-based problem-based learning (PBL) approach, a digital technology-supported approach and more. It also reports on how, when teaching and learning culture, teachers’ professional identity and the informal teaching and learning environment impact the teaching and learning......, but instead, should explore how the context may be integrated into and used constructively in the teaching and learning of culture. This allowance of context in the classroom will allow for teachers, students, subjects and contexts to enter into a dialogue and negotiation of meaning that will enrich each...

  5. Profile of World Uranium Enrichment Programs - 2007

    Laughter, Mark D [ORNL

    2007-11-01

    It is generally agreed that the most difficult step in building a nuclear weapon is acquiring weapons grade fissile material, either plutonium or highly enriched uranium (HEU). Plutonium is produced in a nuclear reactor, while 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 in fuel for nuclear reactors. However, the same equipment used to produce LEU for nuclear 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 only enriched to LEU, no undeclared LEU is produced, and no uranium is enriched to HEU or secretly diverted. 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 53 million kg-separative work units (SWU) per year, with 22 million in gaseous diffusion and 31 million in gas centrifuge plants. Another 23 million SWU/year of capacity are 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

  6. 溶解氧浓度对连续流活性污泥工艺反硝化除磷的影响%Effects of dissolved oxygen concentration on denitrifying phosphorus removal in continuous-flow activated sludge process

    王荣昌; 司书鹏; 郑翔; 杨殿海; 励建全; 赵建夫

    2011-01-01

    @@ 引言 随着水体富营养化问题的日渐突出,污水处理技术逐渐从单一去除有机物为目的的阶段进入既要去除有机物又要脱氮除磷的深度处理阶段[1].%Effects of dissolved oxygen (DO) concentration on removal performance of nitrogen and phosphorus were investigated in a pilot-scale anaerobic-anoxic-aerobic (A2/O) activated sludge process for treating municipal wastewater. During run operation, sludge recycling ratio and internal mixed liquid recirculation ratio were kept constant at 150% and 100%, respectively. The results showed that DO concentration played an important role in nutrient removal by A2/O process. Denitrifying phosphorus removal was observed when aerobic tank was kept at low DO (DO=1. 0-1.5 mg · L-1) conditions. The best performance of nutrient removal was achieved when DO concentration was kept at 0. 2 mg · L-1 in anoxic tank and 1.0 mg · L-1 in aerobic tank. Total nitrogen (TN) and total phosphorus (TP) removal was about 64.6% and 89.6%, respectively. TN and TP concentration in the effluent was (11.9± 5. 3)mg · L-1and (0. 17±0.09) mg· L-1 , respectively. TP removal in anoxic tank was about 48.2% of the total TP removal by the whole process. Denitrifying phosphorus removal became an important way of dephosphorization. Denitrifying phosphorus removal bacteria (DPB) accounted for 55.7% of the total phosphorus accumulating organisms (PAOs) based on the results of denitrifying phosphorus removal activity analysis. The analysis for particle diameter distributions showed that the particle diameter of activated sludge in aerobic tank was larger than those in anaerobic and anoxic tanks. Larger particle diameter resulted in the existence of anaerobic or anoxic microenvironments in the sludge particles in aerobic tank, which favored the survival and propagation of DPBs in the whole system. Therefore, the nutrient removal performance and cost-efficiency of conventional activated sludge processes can

  7. Investigation on the effect of denitrified fly ash on the properties of cement%脱硝粉煤灰对水泥性能影响的研究

    王穆君; 徐玲玲; 刘方; 汪洋; 叶强; 杨尚富; 刘韬

    2011-01-01

    Denitrified fly ash is a solid by-product of thermal power plant denitrificat]on process used to reduce NOx emissions. With the popularizing of this technique in power plant,fly ash produced by low-NOx combustion will be the major type of fly ash. Therefore,its comprehensive utilization has practical significance. In this paper three samples of fly ash with low-NOx combustion from different power plants have been studied to replace the cement with weight percentage of 10%,20%,30% and 40%. Their effects on cement properties were tested. The results show that the effect of denitrified fly ash is nearly the same as that of ordinary fly ash. As it has certain water reducing effect.the flowability of cement is increased,setting time is prolonged and the earlier stage strength is lowered. Such effect strengthens with the increasing of denitrified fly ash content. To ensure the stability of cement with denitrified fly ash,the CaO content in denitrified fly ash should be considered when determining the percentage of fly ash adding into cement.%脱硝粉煤灰是火电厂采用脱硝工艺减少NOx气体排放时的固体副产物,随着脱硝工艺的普及,脱硝粉煤灰将成为主要的粉煤灰种类,因此其综合利用具有重大的实际意义.主要研究了3种采集自不同电厂的脱硝粉煤灰以10%、20%、30%和40%掺入水泥中对水泥性能的影响,结果表明,脱硝粉煤灰对水泥性能的作用类似于普通粉煤灰,具有一定的减水作用,提高了水泥的流动度,但延长了水泥的凝结时间,并降低了水泥的早期强度,这些作用随着粉煤灰掺量的增加而增强.在设计粉煤灰掺量时必须考虑粉煤灰中CaO的含量,以保证水泥的安定性合格.

  8. 77 FR 13367 - General Electric-Hitachi Global Laser Enrichment, LLC, Proposed Laser-Based Uranium Enrichment...

    2012-03-06

    ... COMMISSION General Electric-Hitachi Global Laser Enrichment, LLC, Proposed Laser-Based Uranium Enrichment...- Hitachi Global Laser Enrichment, LLC (GLE) Uranium Enrichment Facility. On June 26, 2009, GLE submitted a... uranium enrichment facility (the ``proposed action''). The GLE proposes to locate the facility on...

  9. Management's Ecstasy and Disparity Over Job Enrichment

    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)

  10. 氮肥对稻田土壤反硝化细菌群落结构和丰度的影响%Response of denitrifying bacteria community structure and abundance to nitrogen in paddy fields

    宋亚娜; 林智敏; 林艳

    2012-01-01

    Denitrification is critical for nitrogen cycle in the ecosystem,where fixed nitrogen is released into the atmosphere as N2.Nitrite reductase,the product of nirS or nirK nitrite reductase genes,is the key enzyme of bacteria dissimilatory denitrification process.Denitrifying bacteria community composition varies with environmental factors such as temperature,moisture,pH,O2 and nutrient availability.There is obvious denitrification process in flooded paddy fields.Hence denitrifying bacteria community structure and abundance in paddy fields are used to investigate the response of denitrifying bacteria to nitrogen fertilizer application in paddy fields.The experiment was conducted in a second-year nitrogen fertilization field with the aid of denaturing gradient gel electropho-resis and real-time PCR assay copies of nirS gene.DGGE images of nirS gene in root-zone soil and surface soil showed rich abun-dance of denitrifying bacteria in paddy soils.DGGE band number in surface soil image was higher than that in root-zone soil.Principle components analysis (PCA) of nirS gene DGGE profile showed that denitrifying bacteria community structure in root-zone or surface soil of paddy fields with nitrogen fertilizer [N: 150 kg(N)-hm-2] was similar to that of paddy fields without fertilizer (CK) during rice growth stages of tillering,heading and maturity.Also no difference was noted in denitrifying bacteria community structure in root-zone soil or surface soil among different growth stages of rice.Denitrifying bacteria nirS gene copy abundance in root-zone or in surface soil with nitrogen fertilizer treatment was significantly (P < 0.05) higher than that of CK treatment during rice growth.In both nitrogen fertilizer and CK treatments,denitrifying bacteria nirS gene copies in root-zone soil markedly (P < 0.05) dropped at maturity stage of rice growth.There were,however,no differences in nirS gene copies in surface soil among the different rice growth stages.At maturity stage

  11. Microbial community structure and function in response to the shift of sulfide/nitrate loading ratio during the denitrifying sulfide removal process.

    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.

  12. Nitrogen-removal efficiency of a novel aerobic denitrifying bacterium, Pseudomonas stutzeri strain ZF31, isolated from a drinking-water reservoir.

    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.

  13. Molecular and Kinetic Characterization of Planktonic Nitrospira spp. Selectively Enriched from Activated Sludge.

    Park, Mee-Rye; Park, Hongkeun; Chandran, Kartik

    2017-03-07

    Nitrospira spp. are chemolithoautotrophic nitrite-oxidizing bacteria (NOB), which are ubiquitous in natural and engineered environments. However, there exist few independent biokinetic studies on Nitrospira spp., likely because their isolation and selective enrichment from environmental consortia such as activated sludge can be challenging. Herein, planktonic Nitrospira spp. cultures closely related to Candidatus Nitrospira defluvii (Nitrospira lineage I) were successfully enriched from activated sludge in a sequencing batch reactor by maintaining sustained limiting extant nitrite and dissolved oxygen concentrations. Morphologically, the enrichment consisted largely of planktonic cells with an average characteristic diameter of 1.3 ± 0.6 μm. On the basis of respirometric assays, estimated maximum specific growth rate (μmax), nitrite half saturation coefficient (KS), oxygen half saturation coefficient (KO), and biomass yield coefficient (Y) of the enriched cultures were 0.69 ± 0.10 d(-1), 0.52 ± 0.14 mg-N/L, 0.33 ± 0.14 mg-O2/L, and 0.14 ± 0.02 mg-COD/mg-N, respectively. These parameters collectively reflect not just higher affinities of this enrichment for nitrite and oxygen, respectively, but also a higher biomass yield and energy transfer efficiency relative to Nitrobacter spp. Used in combination, these kinetic and thermodynamic parameters can help toward the development and application of energy-efficient biological nutrient removal processes through effective Nitrospira out-selection.

  14. Dialogismo, lenguas extranjeras e identidad cultural (Dialogism, Foreign Languages, and Cultural Identity).

    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…

  15. A combined enrichment/polymerase chain reaction based method for the routine screening of streptococcus agalactiae in pregnant women

    MUNARI, F. M.; de-Paris,F.; Salton, G.D.; Lora,P.S; Giovanella, P.; Machado, A.B.M.P.; Laybauer, L.S.; Oliveira, K.R.P.; C. Ferri; Silveira, J.L.S.; Laurino,C.C.F.C; Xavier, R.M.; Barth,A.L.; S Echeverrigaray; Laurino, J.P.

    2012-01-01

    Group B Streptococcus (GBS) is the most common cause of life-threatening infection in neonates. Guidelines from CDC recommend universal screening of pregnant women for rectovaginal GBS colonization. The objective of this study was to compare the performance of a combined enrichment/PCR based method targeting the atr gene in relation to culture using enrichment with selective broth medium (standard method) to identify the presence of GBS in pregnant women. Rectovaginal GBS samples from women a...

  16. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    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.

  17. Contribution of enrichments and resampling for sulfate reducing bacteria diversity assessment by high-throughput cultivation.

    Colin, Yannick; Goñi-Urriza, Marisol; Caumette, Pierre; Guyoneaud, Rémy

    2015-03-01

    The development of new high-throughput cultivation methods aims to increase the isolation efficiency as compared to standard techniques that often require enrichment procedures to compensate the low microbial recovery. In the current study, estuarine sulfate-reducing bacteria were isolated using an anaerobic isolation procedure in 384-well microplates. Ninety-nine strains were recovered from initial sediments. Isolates were identified according to their partial 16S rRNA sequences and clustered into 13 phylotypes. Besides, the increase in species richness obtained through enrichments or resampling was investigated. Forty-four enrichment procedures were conducted and shifts in sulfate-reducing bacterial communities were investigated through dsrAB gene fingerprinting. Despite efforts in conducting numerous enrichment conditions only few of them were statistically different from initial sample. The cultural diversity obtained from 3 of the most divergent enrichments, as well as from resampled sediments equally contributed to raise the sulfate-reducing diversity up to 22 phylotypes. Enrichments (selection of metabolism) or resampling (transient populations and micro-heterogeneity) may still be helpful to assess new microbial phylotypes. Nevertheless, all the newly cultivated strains were all representatives of minor Operational Taxonomic Units and could eventually be recovered by maintaining high-throughput isolation effort from the initial sediments.

  18. Characterization of four TCE-dechlorinating microbial enrichments grown with different cobalamin stress and methanogenic conditions.

    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 B₁₂ 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 B₁₂ 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 B₁₂ amendment and active methanogenesis. Principal component analysis revealed that active methanogenesis, rather than vitamin B₁₂ 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.

  19. Enrichment of Mouse Spermatogonial Stem Cells by the Stem Cell Dye CDy1.

    Kanatsu-Shinohara, Mito; Morimoto, Hiroko; Shinohara, Takashi

    2016-01-01

    Spermatogonial stem cells (SSCs) comprise a small population of germ cells with self-renewal potential. Previous studies have shown that SSCs share several common features with stem cells in other self-renewing tissues, including surface markers and proliferative machinery. However, studies of SSCs are severely handicapped by the small number of SSCs and the lack of SSC-specific markers. In the present study, we examined the utility of CDy1 and Rh123, both of which are used for the collection of stem cells in several self-renewing tissues. CDy1 stained germline stem (GS) cells, cultured spermatogonia enriched for SSC activity, after in vitro incubation without exerting toxic effects. Unlike previously reported stem cell-specific dyes, CDy1 was also useful for enrichment of SSCs in both GS cell culture and mature adult testes. Spermatogonial transplantation showed that ∼1 in 66.7 cells exhibited SSC activity after CDH1-based magnetic cell selection and CDy1 staining. In contrast, although Rh123 was previously used successfully to collect SSCs from cryptorchid testes, it was not possible to recover SSCs from both GS cell cultures and wild-type testes. Thus, CDy1 staining will provide a useful strategy for the enrichment of SSCs and may be used in conjunction with other reagents for the enrichment of SSCs.

  20. Enrichment and isolation of Flavobacterium strains with tolerance to high concentrations of cesium ion.

    Kato, Souichiro; Goya, Eri; Tanaka, Michiko; Kitagawa, Wataru; Kikuchi, Yoshitomo; Asano, Kozo; Kamagata, Yoichi

    2016-02-17

    Interest in the interaction of microorganisms with cesium ions (Cs(+)) has arisen, especially in terms of their potent ability for radiocesium bioaccumulation and their important roles in biogeochemical cycling. Although high concentrations of Cs(+) display toxic effects on microorganisms, there have been only limited reports for Cs(+)-tolerant microorganisms. Here we report enrichment and isolation of Cs(+)-tolerant microorganisms from soil microbiota. Microbial community analysis revealed that bacteria within the phylum Bacteroidetes, especially Flavobacterium spp., dominated in enrichment cultures in the medium supplemented with 50 or 200 mM Cs(+), while Gammaproteobacteria was dominant in the control enrichment cultures (in the presence of 50 and 200 mM K(+) instead of Cs(+)). The dominant Flavobacterium sp. was successfully isolated from the enrichment culture and was closely related to Flavobacterium chungbukense with 99.5% identity. Growth experiments clearly demonstrated that the isolate has significantly higher tolerance to Cs(+) compared to its close relatives, suggesting the Cs(+)-tolerance is a specific trait of this strain, but not a universal trait in the genus Flavobacterium. Measurement of intracellular K(+) and Cs(+) concentrations of the Cs(+)-tolerant isolate and its close relatives suggested that the ability to maintain low intracellular Cs(+) concentration confers the tolerance against high concentrations of external Cs(+).

  1. Urine culture

    Culture and sensitivity - urine ... when urinating. You also may have a urine culture after you have been treated for an infection. ... when bacteria or yeast are found in the culture. This likely means that you have a urinary ...

  2. Classification of positive blood cultures

    Gradel, Kim Oren; Knudsen, Jenny Dahl; Arpi, Magnus

    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 administrative data and computer algorithms, taking physicians assessments as reference. METHODS: Physicians...... assessments of positive blood cultures were routinely recorded at two Danish hospitals from 2006 through 2008. The physicians assessments classified positive blood cultures as: a) contamination or bloodstream infection; b) bloodstream infection as mono- or polymicrobial; c) bloodstream infection as community...

  3. Safeguards Culture

    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.

  4. Organizational Culture

    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.

  5. Early Recovery of Salmonella from Food Using a 6-Hour Non-selective Pre-enrichment and Reformulation of Tetrathionate Broth

    Daquigan, Ninalynn; Grim, Christopher J.; White, James R.; Hanes, Darcy E.; Jarvis, Karen G.

    2016-01-01

    Culture based methods are commonly employed to detect pathogens in food and environmental samples. These methods are time consuming and complex, requiring multiple non-selective and selective enrichment broths, and usually take at least 1 week to recover and identify pathogens. Improving pathogen detection in foods is a primary goal for regulatory agencies and industry. Salmonella detection in food relies on a series of culture steps in broth formulations optimized to resuscitate Salmonella and reduce the abundance of competitive bacteria. Examples of non-selective pre-enrichment broths used to isolate Salmonella from food include Lactose, Universal Pre-enrichment, BPW, and Trypticase Soy broths. Tetrathionate (TT) and Rappaport–Vassiliadis (RV) broths are employed after a 24-h non-selective enrichment to select for Salmonella and hamper the growth of competitive bacteria. In this study, we tested a new formulation of TT broth that lacks brilliant green dye and has lower levels of TT . We employed this TT broth formulation in conjunction with a 6-h non-selective pre-enrichment period and determined that Salmonella recovery was possible one day earlier than standard food culture methods. We tested the shortened culture method in different non-selective enrichment broths, enumerated Salmonella in the non-selective enrichments, and used 16S rRNA gene sequencing to determine the proportional abundances of Salmonella in the TT and RV selective enrichments. Together these data revealed that a 6-h non-selective pre-enrichment reduces the levels of competitive bacteria inoculated into the selective TT and RV broths, enabling the recovery of Salmonella 1 day earlier than standard culture enrichment methods. PMID:28082968

  6. Conversion of Crude Oil to Methane by a Microbial Consortium Enriched From Oil Reservoir Production Waters

    Carolina eBerdugo-Clavijo

    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 μmol 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.

  7. Characteristics of phosphorus removal microorganisms in denitrifying phosphorus removal and induced crystallization phosphorus recovery process for waste water treatment%污水处理反硝化除磷-诱导结晶磷回收工艺中除磷微生物特性

    邹海明; 吕锡武; 李婷

    2014-01-01

    为探究反硝化除磷-诱导结晶磷回收工艺中缺氧池污泥释磷、吸磷以及微生物特征,利用荧光原位杂交(fluorescence in situ hybridization,FISH)技术、电子扫描显微镜(scanning electron microscope,SEM)观察了微生物的数量、分布和形态;通过批次试验考察了污泥在厌氧/好氧和厌氧/缺氧2种模式下的释磷和吸磷特征。结果表明:该双污泥系统缺氧池中聚磷菌占总细菌比例的69.7%,明显高于单污泥系统中富集的聚磷菌比例,污泥中的微生物多呈杆状;厌氧/好氧、厌氧/缺氧模式下单位污泥浓度(mixed liquor suspended solids,MLSS)总吸磷量(以PO43--P计)分别为22.84、18.60 mg/g,反硝化聚磷菌(denitrifying polyphosphate-accumulating organisms, DPAO)占聚磷菌(polyphosphate-accumulating organisms,PAO)的比例为81.44%,表明在长期的厌氧/缺氧运行条件下可以富集到以硝酸盐为电子受体的反硝化聚磷菌,同时还存在着仅以氧气为电子受体的聚磷菌;通过 pH值和氧化还原电位(oxidation reduction potential,ORP)的实时监测可以快速地了解污水生物处理系统中各类反应的进程,对调控工艺参数有着重要的意义。综上所述,为保证污水生物处理工艺的正常稳定运行,将微生物分析与常规的化学参数分析结合起来考察将是未来发展的必然趋势。%A novel wastewater treatment process in our previous research can perform denitrifying simultaneous nitrogen and phosphorus removal and phosphorus recovery via induced crystallization (thereafter called BNR-IC process). Generally, removal efficiencies of contaminants including carbon, nitrogen and phosphorus through wastewater biological treatment process may be attributed to characteristics of predominant microorganisms in activated sludge. In this BNR-IC process, microorganism enriched in the anoxic tank is one of key factors influencing

  8. Enrichment of Acinetobacter spp. from food samples.

    Carvalheira, Ana; Ferreira, Vânia; Silva, Joana; Teixeira, Paula

    2016-05-01

    Relatively little is known about the role of foods in the chain of transmission of acinetobacters and the occurrence of different Acinetobacter spp. in foods. Currently, there is no standard procedure to recover acinetobacters from food in order to gain insight into the food-related ecology and epidemiology of acinetobacters. This study aimed to assess whether enrichment in Dijkshoorn enrichment medium followed by plating in CHROMagar™ Acinetobacter medium is a useful method for the isolation of Acinetobacter spp. from foods. Recovery of six Acinetobacter species from food spiked with these organisms was compared for two selective enrichment media (Baumann's enrichment and Dijkshoorn's enrichment). Significantly (p Acinetobacter was applied to detect Acinetobacter spp. in different foods. Fourteen different presumptive acinetobacters were recovered and assumed to represent nine different strains on the basis of REP-PCR typing. Eight of these strains were identified by rpoB gene analysis as belonging to the species Acinetobacter johnsonii, Acinetobacter calcoaceticus, Acinetobacter guillouiae and Acinetobacter gandensis. It was not possible to identify the species level of one strain which may suggests that it represents a distinct species.

  9. Profile of World Uranium Enrichment Programs-2009

    Laughter, Mark D [ORNL

    2009-04-01

    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

  10. In vitro antioxidant activities of antioxidant-enriched toothpastes.

    Battino, M; Ferreiro, M S; Armeni, T; Politi, A; Bompadre, S; Massoli, A; Bullon, P

    2005-03-01

    Several forms of periodontal diseases (PD) are often associated with modified phagocytosing leukocytes and contemporary free radical production. Host antioxidant defenses could benefit from toothpastes used as adjuncts to counteract plaque-associated bacteria. The aim of the present study was to determine possible antioxidant activity (AA) of 12 differently antioxidant-enriched toothpastes, regardless of their efficacy as antimicrobial agents. Toothpastes were enriched alternatively with sodium ascorbyl phosphate, alpha-tocopherol acetate, pycnogenol, allantoin and methyl salycilate or a mixture of these. AA was tested in a cell-free system with a ABTS-decolorization assay improved by means of a flow injection analysis device. Comet assay, using NCTC 2544 keratinocytes, was performed to test if it was possible to identify any protection against in vitro DNA fragmentation provoked by a challenge with H(2)O(2) in cultures pre-incubated with toothpaste extracts. Only toothpastes containing sodium ascorbyl phosphate displayed clear AA with I(50) values ranging between 50 and 80 mg of toothpaste/ml water. COMET analysis of cells challenged with H(2)O(2) in presence of toothpaste extracts revealed a limited protection exerted by sodium ascorbyl phosphate. The results described herein indicate that toothpastes containing sodium ascorbyl phosphate possess AA. All the data were obtained in systems in vitro and the demonstration of in vivo AA is desirable. These findings could be useful in the treatment and maintenance of some forms of PD and should be considered when arranging new toothpaste formulations.

  11. Industrial cultures

    Rasmussen, Lauge Baungaard

    1996-01-01

    The chapter deals with different paradigms andtheories of cultural development. The problem toexplain change and methods to analyse developmentin different cultures are presented and discussed.......The chapter deals with different paradigms andtheories of cultural development. The problem toexplain change and methods to analyse developmentin different cultures are presented and discussed....

  12. Nutrient enrichment increases mortality of mangroves.

    Catherine E Lovelock

    Full Text Available Nutrient enrichment of the coastal zone places intense pressure on marine communities. Previous studies have shown that growth of intertidal mangrove forests is accelerated with enhanced nutrient availability. However, nutrient enrichment favours growth of shoots relative to roots, thus enhancing growth rates but increasing vulnerability to environmental stresses that adversely affect plant water relations. Two such stresses are high salinity and low humidity, both of which require greater investment in roots to meet the demands for water by the shoots. Here we present data from a global network of sites that documents enhanced mortality of mangroves with experimental nutrient enrichment at sites where high sediment salinity was coincident with low rainfall and low humidity. Thus the benefits of increased mangrove growth in response to coastal eutrophication is offset by the costs of decreased resilience due to mortality during drought, with mortality increasing with soil water salinity along climatic gradients.

  13. Uranium enrichment management review: summary of analysis

    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.

  14. Nutrient Enrichment Increases Mortality of Mangroves

    Lovelock, Catherine E.; Ball, Marilyn C.; Martin, Katherine C.; C. Feller, Ilka

    2009-01-01

    Nutrient enrichment of the coastal zone places intense pressure on marine communities. Previous studies have shown that growth of intertidal mangrove forests is accelerated with enhanced nutrient availability. However, nutrient enrichment favours growth of shoots relative to roots, thus enhancing growth rates but increasing vulnerability to environmental stresses that adversely affect plant water relations. Two such stresses are high salinity and low humidity, both of which require greater investment in roots to meet the demands for water by the shoots. Here we present data from a global network of sites that documents enhanced mortality of mangroves with experimental nutrient enrichment at sites where high sediment salinity was coincident with low rainfall and low humidity. Thus the benefits of increased mangrove growth in response to coastal eutrophication is offset by the costs of decreased resilience due to mortality during drought, with mortality increasing with soil water salinity along climatic gradients. PMID:19440554

  15. Role of epithelial-mesenchymal transition in the enrichment of colorectal cancer stem cells

    Jia-ping CHENG

    2016-10-01

    Full Text Available Objective  To explore whether the enrichment of cancer stem cells (CSCs in colorectal cancer by suspension culture method is involved with epithelial-mesenchymal transition (EMT. Methods  3D microspheres were cultured by suspension culture method to human colorectal cancer SW620 cells. The 3D microspheres and SW620 cells were used as the research objects. To clarify whether 3D microspheres were enriched with CSCs, we made tumorigenicity experiments in NOD/SCID mice, soft agar cloning experiments, and detected the expression levels of cancer stem cells markers CD44 and Ep-CAM by flow cytometry or by Western blotting. The protein expression levels of EMT markers such as E-cadherin, N-cadherin and vimentin were detected by Western blotting. Results  Compared with the parental SW620 cells, colony formation in vitro (P<0.01 and tumorigenicity in NOD/SCID mice were significantly enhanced, the percentage of CD44-positive cells and Ep-CAM protein expression levels was significantly increased (P<0.01 in 3D microspheres. The protein expression level of epithelial marker E-cadherin was obviously increased (P<0.01, while the protein expression levels of mesenchymal markers N-cadherin and vimentin were significantly decreased (P<0.01. Conclusions  Colorectal cancer stem cells can be enriched by suspension culture method, and the process may be related to EMT. DOI: 10.11855/j.issn.0577-7402.2016.09.03

  16. Technical considerations for the use of passive samplers to quantify the isotopic composition of NOx and NO2 using the denitrifier method

    Dahal, Bigyan; Hastings, Meredith G.

    2016-10-01

    The isotopic composition of nitrogen oxides (NOx = NO + NO2) hold potential to trace emissions sources, as well as chemistry in the atmosphere. Passive samplers that collect NOx and NO2 as nitrite could provide a simple and inexpensive means by which to collect samples in a variety of environments, and we report here on several methodological considerations when using Ogawa passive collectors of NOx and NO2 for concentration analysis via colorimetric methods and isotopic analysis via the denitrifier method. Using Ogawa samplers, NOx and NO2 were collected in Providence, RI, USA (41.8°N, 71.4°W) with exposure times of seven, fourteen, twenty-one, and twenty-eight days during summer and winter in an area dominated by vehicle emissions, particularly diesel delivery trucks. Average values were -9.7 ± 0.7‰ for δ15N-NOx and -8.3 ± 0.9‰ for δ15N-NO2 based on duplicate seven, fourteen, twenty-one, and twenty-eight day exposures (n = 8) in summertime, and -11.9 ± 0.7‰ for δ15N-NOx and -6.4 ± 1.4‰ for δ15N-NO2 based on seven, fourteen, twenty-one, and twenty-eight day exposures (n = 7) in wintertime. The oxygen isotopic composition (δ18O, Δ17O) was also determined with averages of: 36.3 ± 2.4‰ for δ18O-NOx (n = 8), 50.5 ± 3.2‰ for δ18O-NO2 (n = 8), 6.2 ± 0.8‰ for Δ17O-NOx and 10.8 ± 0.6‰ for Δ17O-NO2 (n = 4) in summer; and 38.7 ± 2.9‰ for δ18O-NOx and 47.4 ± 1.2‰ for δ18O-NO2 (n = 7), 7.7 ± 1.5‰ for Δ17O-NO2 (n = 4) and 5.3 ± 1.2‰ for Δ17O-NOx (n = 5), in winter. Our isotopic results differ from previous studies that utilized passive samplers and suggest specific nitrogen and oxygen isotopic signatures associated with vehicular emissions. To collect sufficient sample for multiple isotopic analyses (e.g., 10 nmol N for δ15N and δ18O; 50 nmol N for Δ17O) the exposure time for the samplers, even in urban areas, is at least days. This necessarily results in collection of a mixture of local emissions sources, as well as

  17. 21 CFR 136.115 - Enriched bread, rolls, and buns.

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Enriched bread, rolls, and buns. 136.115 Section... § 136.115 Enriched bread, rolls, and buns. (a) Each of the foods enriched bread, enriched rolls, and... label statement of ingredients prescribed for bread, rolls or buns by § 136.110, except that: (1)...

  18. Phosphopeptide enrichment by immobilized metal affinity chromatography

    Thingholm, Tine E.; Larsen, Martin R.

    2016-01-01

    Immobilized metal affinity chromatography (IMAC) has been the method of choice for phosphopeptide enrichment prior to mass spectrometric analysis for many years and it is still used extensively in many laboratories. Using the affinity of negatively charged phosphate groups towards positively...... charged metal ions such as Fe3+, Ga3+, Al3+, Zr4+, and Ti4+ has made it possible to enrich phosphorylated peptides from peptide samples. However, the selectivity of most of the metal ions is limited, when working with highly complex samples, e.g., whole-cell extracts, resulting in contamination from...

  19. Cr(VI) removal from aqueous solution by thermophilic denitrifying bacterium Chelatococcus daeguensis TAD1 in the presence of single and multiple heavy metals.

    Li, Han; Huang, Shaobin; Zhang, Yongqing

    2016-09-01

    Cr(VI) pollution is increasing continuously as a result of ongoing industrialization. In this study, we investigated the thermophilic denitrifying bacterium Chelatococcus daeguensis TAD1, isolated from the biofilm of a biotrickling filter used in nitrogen oxides (NOX) removal, with respect to its ability to remove Cr(VI) from an aqueous solution. TAD1 was capable of reducing Cr(VI) from an initial concentration of 10 mg/L to non-detectable levels over a pH range of 7-9 and at a temperature range of 30-50°C. TAD1 simultaneously removed both Cr(VI) and NO3 (-)-N at 50°C, when the pH was 7 and the initial Cr(VI) concentration was 15 mg/L. The reduction of Cr(VI) to Cr(III) correlated with the growth metabolic activity of TAD1. The presence of other heavy metals (Cu, Zn, and Ni) inhibited the ability of TAD1 to remove Cr(VI). The metals each individually inhibited Cr(VI) removal, and the extent of inhibition increased in a cooperative manner in the presence of a combination of the metals. The addition of biodegradable cellulose acetate microspheres (an adsorption material) weakened the toxicity of the heavy metals; in their presence, the Cr(VI) removal efficiency returned to a high level. The feasibility and applicability of simultaneous nitrate removal and Cr(VI) reduction by strain TAD1 is promising, and may be an effective biological method for the clean-up of wastewater.

  20. Effects of planting Phragmites australis on nitrogen removal, microbial nitrogen cycling, and abundance of ammonia-oxidizing and denitrifying microorganisms in sediments.

    Toyama, Tadashi; Nishimura, Yoshiko; Ogata, Yuka; Sei, Kazunari; Mori, Kazuhiro; Ike, Michihiko

    2015-10-21

    We examined the effect of planting an emergent aquatic plant (Phragmites australis) on nitrogen removal from sediments using a 42-d pot experiment. The experimental pot systems comprised two types of sediments planted with and without young P. australis. Total nitrogen (total N), total dissolved N, and NH4-N in the sediments decreased markedly after planting. In contrast, those levels decreased only slightly in the unplanted sediments. The decrease in total N in the P. australis-planted sediments was 7-20 times those in the unplanted sediments. Abundances of bacterial 16S rRNA, archaeal 16S rRNA, ammonia-oxidizing bacterial ammonia monooxygenase (amoA), ammonia-oxidizing archaeal amoA, and denitrifying bacterial nitrite reductase (nirK) genes increased significantly in sediments after planting. Phragmites australis appears to have released oxygen and created a repeating cycle of oxidizing and reducing conditions in the sediments. These conditions should promote mineralization of organic N, nitrification, and denitrification in the sediments. Phragmites australis absorbed bioavailable nitrogen generated by microbial nitrogen metabolism. During the 42-d period after planting, 31-44% of total N was removed by microbial nitrogen cycling, and 56-69% was removed via absorption by P. australis. These results suggest that planting P. australis can increase microbial populations and their activities, and that nitrogen removal can be accelerated by the combined functions of P. australis and microorganisms in the sediment. Thus, planting P. australis has considerable potential as an effective remediation technology for eutrophic sediments.

  1. 3D microfilter device for viable circulating tumor cell (CTC) enrichment from blood.

    Zheng, Siyang; Lin, Henry K; Lu, Bo; Williams, Anthony; Datar, Ram; Cote, Richard J; Tai, Yu-Chong

    2011-02-01

    Detection of circulating tumor cells has emerged as a promising minimally invasive diagnostic and prognostic tool for patients with metastatic cancers. We report a novel three dimensional microfilter device that can enrich viable circulating tumor cells from blood. This device consists of two layers of parylene membrane with pores and gap precisely defined with photolithography. The positions of the pores are shifted between the top and bottom membranes. The bottom membrane supports captured cells and minimize the stress concentration on cell membrane and sustain cell viability during filtration. Viable cell capture on device was investigated with scanning electron microscopy, confocal microscopy, and immunofluorescent staining using model systems of cultured tumor cells spiked in blood or saline. The paper presents and validates this new 3D microfiltration concept for circulation tumor cell enrichment application. The device provides a highly valuable tool for assessing and characterizing viable enriched circulating tumor cells in both research and clinical settings.

  2. Isolation and Enrichment of Mouse Female Germ Line Stem Cells

    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.

  3. Enrichment and Function Research of Large Cell Lung Cancer Stem Cell-like Cells

    Wenke YUE

    2011-06-01

    Full Text Available Background and objective There are no universal method to recognize and screen for lung cancer stem cell markers and indicators. Commonly used methods are flow Cytometry and learning from other cancer stem cell sorting tags to sort lung cancer stem cells. But this method has low specificity screening, the workload is huge. In this study, Serum-free suspension culture was used to enrich lung cancer stem cells, and explore method for lung cancer stem cell screening. Methods Human large lung cancer cell line-L9981 was cultured in serum-free and growth factors added medium, and spheres were obtained. Then the morphological differences of sphere cells and adherent L9981 cells cultured in serum-containing mediums are observed. Cell proliferation was analyzed by Vi-cell viability analyzer; invasion ability was tested by transwell assay; and in vivo tumorigenicity of the two groups of cells was studied in nude mouse. Results Compared with adherent L9981 cells cultured in serum-containing mediums, cells cultured in serum-free medium display sphere appearance. Doubling time of adherent cells and sphere cells are (56.05±1.95 h and (33.00±1.44 h respectively; Spheroid cells had higher invasion and tumorigenicity ability, 5 times and 20 times respectively, than adherent cells. Conclusion Suspension cultured L9981 in Serum-free medium could form spheroid populations. Cells in spheres had higher ability of invasion and Tumorigenicity than adherent L9981 cells. These results indicated spheroid L9981 cells contained enriched lung cancer stem cells, and Serum-free suspension culture can be a candidate method for enriching lung cancer stem cell.

  4. 77 FR 14838 - General Electric-Hitachi Global Laser Enrichment LLC, Commercial Laser-Based Uranium Enrichment...

    2012-03-13

    ... COMMISSION General Electric-Hitachi Global Laser Enrichment LLC, Commercial Laser-Based Uranium Enrichment... applicant) to authorize construction of a laser-based uranium enrichment facility and possession and use of...-based uranium enrichment facility. Revisions to the application were submitted on March 23, 2010;...

  5. Global Nomads and the Search for Cultural Identity: Tips from the Classroom

    Al-Issa, Ahmad

    2004-01-01

    Understanding one's cultural system leads to greater skills in appreciating other cultures. When students and teachers from diverse cultural backgrounds come together, they bring diversity that can either improve or break down the process of learning and teaching. If handled properly, cultural diversity can enrich the classroom; if ignored,…

  6. Cultural commons and cultural evolution

    Giangiacomo Bravo

    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 memetic group is a majo...

  7. The Complexity of Enriched Mu-Calculi

    Bonatti, Piero A; Murano, Aniello; Vardi, Moshe Y

    2008-01-01

    The fully enriched mu-calculus is the extension of the propositional mu-calculus with inverse programs, graded modalities, and nominals. While satisfiability in several expressive fragments of the fully enriched mu-calculus is known to be decidable and ExpTime-complete, it has recently been proved that the full calculus is undecidable. In this paper, we study the fragments of the fully enriched mu-calculus that are obtained by dropping at least one of the additional constructs. We show that, in all fragments obtained in this way, satisfiability is decidable and ExpTime-complete. Thus, we identify a family of decidable logics that are maximal (and incomparable) in expressive power. Our results are obtained by introducing two new automata models, showing that their emptiness problems are ExpTime-complete, and then reducing satisfiability in the relevant logics to these problems. The automata models we introduce are two-way graded alternating parity automata over infinite trees (2GAPTs) and fully enriched automa...

  8. Phosphopeptide enrichment by immobilized metal affinity chromatography

    Thingholm, Tine E.; Larsen, Martin R.

    2016-01-01

    Immobilized metal affinity chromatography (IMAC) has been the method of choice for phosphopeptide enrichment prior to mass spectrometric analysis for many years and it is still used extensively in many laboratories. Using the affinity of negatively charged phosphate groups towards positively...

  9. Teaching Mathematical Modelling: Demonstrating Enrichment and Elaboration

    Warwick, Jon

    2015-01-01

    This paper uses a series of models to illustrate one of the fundamental processes of model building--that of enrichment and elaboration. The paper describes how a problem context is given which allows a series of models to be developed from a simple initial model using a queuing theory framework. The process encourages students to think about the…

  10. Implementing the Schoolwide Enrichment Model in Brazil

    de Souza Fleith, Denise; Soriano de Alencar, Eunice M. L.

    2010-01-01

    The Schoolwide Enrichment Model (SEM) has been one of the most widely used models in the education of the gifted in Brazil. It has inspired the political and pedagogical project of the Centers of Activities of High Abilities/Giftedness recently implemented in 27 Brazilian states by the Ministry of Education. In this article, our experience in…

  11. Recommendations based on semantically enriched museum collections

    Wang, Y.; Stash, N.; Aroyo, L.; Gorgels, P.; Rutledge, L.; Schreiber, G.

    2008-01-01

    This article presents the CHIP demonstrator1 for providing personalized access to digital museum collections. It consists of three main components: Art Recommender, Tour Wizard, and Mobile Tour Guide. Based on the semantically enriched Rijksmuseum Amsterdam2 collection, we show how Semantic Web tech

  12. The enrichment history of cosmic metals

    Wiersma, Robert P C; Vecchia, Claudio Dalla; Booth, C M; Theuns, Tom; Aguirre, Anthony

    2010-01-01

    We use a suite of cosmological, hydrodynamical simulations to investigate the chemical enrichment history of the Universe. Specifically, we trace the origin of the metals back in time to investigate when various gas phases were enriched and by what halo masses. We find that the age of the metals decreases strongly with the density of the gas in which they end up. At least half of the metals that reside in the diffuse intergalactic medium (IGM) at redshift zero (two) were ejected from galaxies above redshift two (three). The mass of the haloes that last contained the metals increases rapidly with the gas density. More than half of the mass in intergalactic metals was ejected by haloes with total masses less than 1e11 solar masses and stellar masses less than 1e9 solar masses. The range of halo masses that contributes to the enrichment is wider for the hotter part of the IGM. By combining the `when' and `by what' aspects of the enrichment history, we show that metals residing in lower density gas were typically...

  13. Enrichment Education: Key to NCLEX Success.

    Wolahan, Caryle G. Hussey; Wieczorek, Rita Reis

    1991-01-01

    A concomitant decrease in test scores and major change in the composition of the student body was dealt with by the College of Nursing at the State University of New York through the Nursing Education Success Plan. The plan addresses student preparation for the National Council Licensure Exam (NCLEX), curriculum revision, remediation/enrichment,…

  14. 21 CFR 137.165 - Enriched flour.

    2010-04-01

    ... riboflavin, 24 milligrams of niacin, 0.7 milligrams of folic acid, and 20 milligrams of iron. (b) It may... calcium or wheat germ is excluded in calculating ash content. (f) All ingredients from which the food is... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Enriched flour. 137.165 Section 137.165 Food...

  15. Combined denitrification and phosphorus removal in a biofilter

    Falkentoft, Christina Maria; Harremoes, Poul; Mosbæk, Hans;

    2000-01-01

    A lab-scale biofilter was run continuously for 11/2 years for combined denitrification and phosphorus removal. Alternation between anaerobic and anoxic (nitrate) conditions was used to obtain an enriched culture of denitrifying, phosphate accumulating organisms. Batch experiments were performed...

  16. Separable Bilayer Microfiltration Device for Viable Label-free Enrichment of Circulating Tumour Cells

    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.

  17. Deep Subsurface Life from North Pond: Enrichment, Isolation, Characterization and Genomes of Heterotrophic Bacteria.

    Russell, Joseph A; León-Zayas, Rosa; Wrighton, Kelly; Biddle, Jennifer F

    2016-01-01

    Studies of subsurface microorganisms have yielded few environmentally relevant isolates for laboratory studies. In order to address this lack of cultivated microorganisms, we initiated several enrichments on sediment and underlying basalt samples from North Pond, a sediment basin ringed by basalt outcrops underlying an oligotrophic water-column west of the Mid-Atlantic Ridge at 22°N. In contrast to anoxic enrichments, growth was observed in aerobic, heterotrophic enrichments from sediment of IODP Hole U1382B at 4 and 68 m below seafloor (mbsf). These sediment depths, respectively, correspond to the fringes of oxygen penetration from overlying seawater in the top of the sediment column and upward migration of oxygen from oxic seawater from the basalt aquifer below the sediment. Here we report the enrichment, isolation, initial characterization and genomes of three isolated aerobic heterotrophs from North Pond sediments; an Arthrobacter species from 4 mbsf, and Paracoccus and Pseudomonas species from 68 mbsf. These cultivated bacteria are represented in the amplicon 16S rRNA gene libraries created from whole sediments, albeit at low (up to 2%) relative abundance. We provide genomic evidence from our isolates demonstrating that the Arthrobacter and Pseudomonas isolates have the potential to respire nitrate and oxygen, though dissimilatory nitrate reduction could not be confirmed in laboratory cultures. The cultures from this study represent members of abundant phyla, as determined by amplicon sequencing of environmental DNA extracts, and allow for further studies into geochemical factors impacting life in the deep subsurface.

  18. Enhanced biosynthetically directed fractional carbon-13 enrichment of proteins for backbone NMR assignments.

    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 (600 MHz, 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)Cα-(13)Cβ spin pairs in the amino acids ILV, leading to the absence of Cβ 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.

  19. Throat Culture

    ... 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 ...

  20. Culturing Protozoa.

    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)

  1. Repellent Culture.

    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)

  2. Playful Learning Culture in the Museum

    Marchetti, Emanuela

    2013-01-01

    not undergone much investigation. This study was conducted in cooperation with two historical museums, these being the Transport Museum in Coventry, England and The Viking Museum in Ribe, Denmark. A new learning platform called MicroCulture has been created, aimed at eliciting a sociocultural understanding...... of history in young visitors. This study indicates that museum learning culture could be enriched by the introduction of mediated play as a resource for conceptual thinking and social interaction....

  3. Safety culture

    Keen, L.J. [Canadian Nuclear Safety Commission, Ottawa, Ontario (Canada)

    2003-07-01

    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)

  4. Enrichment of mesophilic acidophiles from the Underground Copper Mine Bor

    Conić Vesna T.

    2009-01-01

    Full Text Available In this work, autotrophic growth of mesophilic acidophiles from the Underground Copper Mine Bor was performed. Two selected solution samples collected from the 'Tilva Roš' ore body were prepared in a 9K nutrient medium (Silverman and Lundgren, 1959. The first sample TR k-16 was obtained during the hole drilling of the ore body, and the second TR k-31 from the drainage channel. Two samples of 9K media (Silverman and Lundgren, 1959 were inoculated with two selected solution samples from the underground mine Tilva Roš. Inoculated culture media were incubated without prior autoclaving in the period of 6 days at a temperature of 28 ?C with purging air through the system with enough oxygen and carbon dioxide. Oxidation rate of ferrous ions in the first 3 days of incubation was 14.8 and 10.7 wt.% Fe2+/day, the next 3 days 17.3 and 13.6 and for the total period of 6 days 98.3 and 74.8 wt.% for the first and second sample, respectively, i.e. 100 wt.% with initial percentage of ferrous ion in each medium. After centrifugation of enriched samples of culture media at 3000 rpm for 5 min, a plenty of mesophilic acidophiles were determined by microscopic method. According to Karavaiko [6], in the processes of incubition for 9K nutrient solution cells number reach a value of 108 cells/cm3.

  5. Handling Culture

    Nispen tot Pannerden, P.J.M. van

    2011-01-01

    The article indicates how companies may prepare for and deal with cultural differences. Because the research base is still rather limited an overall perspective may not be realised. After discussing definitions and concepts of culture, as well as values, cultural differences between states are discu

  6. Beyond Culture.

    Barron, Daniel D.

    1993-01-01

    Discusses the lack of literature relating to cultural differences and school library media programs and reviews the book "Beyond Culture" by Edward T. Hall. Highlights include the population/environment crisis, cultural literacy, the use of technology, and Marshall McLuhan's idea of the global village. (LRW)

  7. Enrichment of breast cancer stem cells using a keratinocyte serum-free medium

    LIU Zhen-zhen; CHEN Ping; LU Zhen-duo; CUI Shu-de; DONG Zi-ming

    2011-01-01

    Background Keratinocyte serum-free medium (K-SFM) is a defined medium used to support the growth of primary keratinocytes and embryonic stem cell. The aim of this research was to optimize enrichment of breast cancer stem cells (CSCs) using K-SFM.Methods A K-SFM was used to enrich CSCs from two breast cancer cell lines and a primary culture of breast cancer.RPMI-1640 supplemented with 10% fetal calf serum (FCS) was used as a control. CSCs were identified with flow cytometry using CD44+/CD24-as molecular markers. The expression of a variety of CSC markers (Oct-4, ABCG2, Nanog,N-cadherin, and E-cadherin) was analyzed with real-time PCR.Results Much higher percentage of CSCs was achieved with K-SFM: 17.3% for MCF-7 cells, 17.4% for SKBR-3, and 20.0% for primary breast cancer culture. Less than 1% CSC was achieved using RPMI-1640 supplemented with 10% FCS. In comparison to the CSCs obtained with RPMI-1640, CSCs in the K-SFM expressed higher levels of Oct-4,ABCG2, Nanog and N-cadherin, and lower level of E-cadherin.Conclusion K-SFM is an optimal culture medium to maintain and to enrich breast CSCs.

  8. Effect of inoculant on diversity of denitrifying bacteria in composting%添加外源菌剂对堆肥中反硝化菌多样性的影响

    许修宏; 卢欣颖; 姜虎; 李洪涛; 陈会海

    2014-01-01

    一氧化二氮还原酶是堆肥发酵中反硝化菌代表性的酶,可较准确地反映出堆肥中反硝化菌的活动状态及反硝化作用状态。文章采用PCR-DGGE方法研究堆肥中反硝化菌群落的变化,结果表明,添加菌剂的堆肥(堆肥Ⅰ和Ⅱ)中反硝化菌的数量与种类都有所增加(尤其是在堆肥Ⅱ中)。通过对DGGE图谱上的条带进行克隆测序,发现测序条带多为假单胞菌。%Nitrous oxide reductase is the representative of denitrifying bacteria accurately reflecting the state of the organisms and denitrification in compost. In this study, PCR-DGGE was used to study the structure and diversity of nitrous oxide reductase bacteria community in compost. The results showed that the number and species of denitrifying bacteria increased in compost (compost Ⅰ and Ⅱ, especial y in compost Ⅱ) inoculated with exogenous organisms. The cloning and sequencing of the DGGE bands revealed that they were affiliated to Pseudomonas.

  9. Observation of high seasonal variation in community structure of denitrifying bacteria in arable soil receiving artificial fertilizer and cattle manure by determining T-RFLP of nir gene fragments

    Priemé, Anders; Wolsing, Martin

    2004-01-01

    Temporal and spatial variation of communities of soil denitrifying bacteria at sites receiving mineral fertilizer (60 and 120 kg N ha-1 year-1) and cattle manure (75 and 150 kg N ha-1 year-1) were explored using terminal restriction fragment length polymorphism (T-RFLP) analyses of PCR amplified...... a significant seasonal shift in the community structure of nirK-containing bacteria. Also, sites treated with mineral fertilizer or cattle manure showed different communities of nirK-containing denitrifying bacteria, since the T-RFLP patterns of soils treated with these fertilizers were significantly different...... nitrite reductase (nirK and nirS) gene fragments. The analyses were done three times during the year: in March, July and October. nirK gene fragments could be amplified in all three months, whereas nirS gene fragments could be amplified only in March. Analysis of similarities in T-RFLP patterns revealed...

  10. Images Bridging Home and Academic Cultures.

    Andres, Sophia

    Often students are unable to draw upon their personal worlds and individual experiences to enrich their writing, suggesting a disparity between home and academic cultures. In light of this apparent disparity, teachers must try to bridge the gap, a task that is possible when the teacher focuses on the germinal, emotional, and unifying qualities of…

  11. Culturally Responsive Computing: A Theory Revisited

    Scott, Kimberly A.; Sheridan, Kimberly M.; Clark, Kevin

    2015-01-01

    Despite multiple efforts and considerable funding, historically marginalized groups (e.g., racial minorities and women) continue not to enter or persist in the most lucrative of fields--technology. Understanding the potency of culturally responsive teaching (CRT), some technology-enrichment programs modified CRP principles to establish a…

  12. Cultural Rights and Cultural Diversity

    WANG SIXIN

    2011-01-01

    @@ Culture is a very big concept, big enough almost to comprise all the activities of human beings and the tangible and intangible results caused by human activities.Therefore, it is very difficult to define culture in a few words.

  13. Cyclohexane-1,2-dione hydrolase from denitrifying Azoarcus sp. strain 22Lin, a novel member of the thiamine diphosphate enzyme family.

    Steinbach, Alma K; Fraas, Sonja; Harder, Jens; Tabbert, Anja; Brinkmann, Henner; Meyer, Axel; Ermler, Ulrich; Kroneck, Peter M H

    2011-12-01

    Alicyclic compounds with hydroxyl groups represent common structures in numerous natural compounds, such as terpenes and steroids. Their degradation by microorganisms in the absence of dioxygen may involve a C-C bond ring cleavage to form an aliphatic intermediate that can be further oxidized. The cyclohexane-1,2-dione hydrolase (CDH) (EC 3.7.1.11) from denitrifying Azoarcus sp. strain 22Lin, grown on cyclohexane-1,2-diol as a sole electron donor and carbon source, is the first thiamine diphosphate (ThDP)-dependent enzyme characterized to date that cleaves a cyclic aliphatic compound. The degradation of cyclohexane-1,2-dione (CDO) to 6-oxohexanoate comprises the cleavage of a C-C bond adjacent to a carbonyl group, a typical feature of reactions catalyzed by ThDP-dependent enzymes. In the subsequent NAD(+)-dependent reaction, 6-oxohexanoate is oxidized to adipate. CDH has been purified to homogeneity by the criteria of gel electrophoresis (a single band at ∼59 kDa; calculated molecular mass, 64.5 kDa); in solution, the enzyme is a homodimer (∼105 kDa; gel filtration). As isolated, CDH contains 0.8 ± 0.05 ThDP, 1.0 ± 0.02 Mg(2+), and 1.0 ± 0.015 flavin adenine dinucleotide (FAD) per monomer as a second organic cofactor, the role of which remains unclear. Strong reductants, Ti(III)-citrate, Na(+)-dithionite, and the photochemical 5-deazaflavin/oxalate system, led to a partial reduction of the FAD chromophore. The cleavage product of CDO, 6-oxohexanoate, was also a substrate; the corresponding cyclic 1,3- and 1,4-diones did not react with CDH, nor did the cis- and trans-cyclohexane diols. The enzymes acetohydroxyacid synthase (AHAS) from Saccharomyces cerevisiae, pyruvate oxidase (POX) from Lactobacillus plantarum, benzoylformate decarboxylase from Pseudomonas putida, and pyruvate decarboxylase from Zymomonas mobilis were identified as the closest relatives of CDH by comparative amino acid sequence analysis, and a ThDP binding motif and a 2-fold Rossmann fold

  14. Challenges when developing omega-3 enriched foods

    Jacobsen, Charlotte

    2010-01-01

    the influence of important factors such as oil quality, delivery systems for omega-3 fatty acids, processing conditions, composition of the food matrix on lipid oxidation in different omega-3 enriched foods (milk, yoghurt, mayonnaise and mayonnaise-based salads, dressing, energy bar and fish paté). Moreover......Due to the polyunsaturated nature of omega-3 fatty acids, lipid oxidation is a major challenge when developing omega-3 enriched foods. In multiphase food systems, several factors can affect lipid oxidation and efficacy of antioxidants, added to prevent lipid oxidation. This review discusses......, the effect of different antioxidants (tocopherol, EDTA, lactoferrin, caffeic acid, ascorbic acid, ascorbyl palmitate, propyl gallate, gallic acid, as well as lipophilized antioxidants) is compared in different food systems....

  15. Uranium enrichment activities: the SILVA program

    Guyot, J.; Cazalet, J.; Camarcat, N.; Figuet, J.

    1994-12-31

    Through its commitment to a nuclear electricity generation policy, France holds today a specific position in the uranium enrichment market thanks to the modern multinational EURODIF gaseous diffusion plant. France has, altogether, a long-term goal in developing SILVA, a laser uranium enrichment process, based on the selective photo-ionization of U-235. After reviewing the fundamentals of SILVA (the laser system with copper vapor lasers and dye lasers and the separator system), a description of the general organization of the R and D program is provided going through basic research, subsystems assessment, production demonstrations and simulations (with the LACAN code), plant design and economics. The general schedule of SILVA is outlined, leading to the possible construction of a commercial plant. 7 figs., 11 refs.

  16. Enriched model categories and diagram categories

    Guillou, Bertrand

    2011-01-01

    We collect in one place a variety of known and folklore results in enriched model category theory and add a few new twists. One twist is a new perspective on equivariant model categories. A central theme is a general procedure for constructing a Quillen adjunction, often a Quillen equivalence, between a given V-model category and a category of diagrams in V, where V is any good enriching category. From this perspective, we rederive the result of Schwede and Shipley that reasonable stable model categories are Quillen equivalent to diagram categories of spectra (alias categories of module spectra). The general theory will be applied to G-spectra in a sequel, and for that we need quite a few technical improvements and modifications of general model categorical results. We collect those here. They are bound to have applications in a variety of other contexts.

  17. Development Issues on Linked Data Weblog Enrichment

    Ruiz-Rube, Iván; Cornejo, Carlos M.; Dodero, Juan Manuel; García, Vicente M.

    In this paper, we describe the issues found during the development of LinkedBlog, a Linked Data extension for WordPress blogs. This extension enables to enrich text-based and video information contained in blog entries with RDF triples that are suitable to be stored, managed and exploited by other web-based applications. The issues have to do with the generality, usability, tracking, depth, security, trustiness and performance of the linked data enrichment process. The presented annotation approach aims at maintaining web-based contents independent from the underlying ontological model, by providing a loosely coupled RDFa-based approach in the linked data application. Finally, we detail how the performance of annotations can be improved through a semantic reasoner.

  18. Free-air CO2 enrichment (FACE) enhances biomass production in a short-rotation poplar plantation

    Calfapietra, C.; Gielen, B.; Galema, A.N.J.; Lukac, M.; Angelis, de P.; Moscatelli, M.C.; Ceulemans, R.; Scarascia-Mugnozza, G.

    2003-01-01

    This paper investigates the possible contribution of Short Rotation Cultures (SRC) to carbon sequestration in both current and elevated atmospheric CO2 concentrations ([CO2]). A dense poplar plantation (1 x 1 m) was exposed to a [CO2] of 550 ppm in Central Italy using the free-air CO2 enrichment (FA

  19. Nutritional Properties of Enriched Local Complementary Flours

    W.R. Compaoré

    2011-02-01

    Full Text Available This study aimed to identify the nutritional, functional, sensory and microbiological profile of experimental nutritional flours, produced with local products in Burkina Faso. The raw materials included maize (Zea mays, millet (Pennisetum glaucum and rice (Oryza sativa. Local ingredients were pulps of Adansonia digitata and Parkia biglobosa and seeds of Cucurbita maxima and Moringa oleifera. Three formula were developed, the first (F1 with maize, the second (F2 with rice and the last (F3 with millet. Each of these cereals was mixed with predetermined portions of seeds and pulps in order to obtain enriched flour. Nutritional, microbiological and functional analysis and the acceptability criteria of these enriched flours were assessed and compared to Misola (F4, the existing local complementary flour. The fat content of experimental flours were respectively in the first (F1, second (F2 and third formula (F3 15.91±0.01%, 11.82±0.02% and 17.02±0.02%. The carbohydrate range was 65.46±0.06%, 70.81±0.01% and 64.51±0.01% for F1, F2 and F3, while the energetic value is higher than recommended (453.07±0.05, 424.56±0.03 and 458.96±0.05 kcal respectively for F1, F2 and F3. Functional characteristics indicated the good viscosity (117, 119 and 121 mm/30 sec for F1, F2 and F3 least gelation (9, 6 and 7% and water absorption capacity (2, 4 and 1 g/g. Trained sensory evaluation panellists gore the enriched flour porridge a score of acceptable. These enriched flours have great potential as a weaning food in resource-poor and technologically under-developed countries.

  20. On Heavy Element Enrichment in Classical Novae

    Alexakis, A; Heger, A; Brown, E F; Dursi, L J; Truran, J W; Rosner, R; Lamb, D Q; Timmes, F X; Fryxell, B; Zingale, M A; Ricker, P M; Olson, K

    2004-01-01

    Many classical nova ejecta are enriched in CNO and Ne. Rosner et al. recently suggested that the enrichment might originate in the resonant interaction between large-scale shear flows in the accreted H/He envelope and gravity waves at the interface between the envelope and the underlying C/O white dwarf. The shear flow amplifies the waves, which eventually form cusps and break. This wave breaking injects a spray of C/O into the superincumbent H/He. Using two-dimensional simulations, we formulate a quantitative expression for the amount of C/O that can be entrained into the H/He at saturation. The fraction of the envelope that is enriched depends on the shear velocity and density contrast between the C/O white dwarf and the H/He layer but is roughly independent of the shape of the shear profile. Using this parameterization for the mixed mass, we then perform several one-dimensional Lagrangian calculations of an accreting white dwarf envelope and consider two scenarios: that the wave breaking and mixing is driv...

  1. Enriching Earthdata by Improving Content Curation

    Bagwell, R.; Wong, M. M.; Murphy, K. J.

    2014-12-01

    Since the launch of Earthdata in the later part of 2011, there has been an emphasis on improving the user experience and providing more enriched content to the user, ultimately with the focus to bring the "pixels to the people" or to ensure that a user clicks the fewest amount of times to get to the data, tools, or information which they seek. Earthdata was founded to be a single source of information for Earth Observing System Data and Information System (EOSDIS) components and services as a conglomeration between over 15 different websites. With an increased focus on access to Earth science data, the recognition is now on transforming Earthdata from a static website to one that is a dynamic, data-driven site full of enriched content.In the near future, Earthdata will have a number of components that will drive the access to the data, such as Earthdata Search, the Common Metadata Repository (CMR), and a redesign of the Earthdata website. The focus on content curation will be to leverage the use of these components to provide an enriched content environment and a better overall user experience, with an emphasis on Earthdata being "powered by EOSDIS" components and services.

  2. Enriched MU-Calculi Module Checking

    Ferrante, Alessandro; Parente, Mimmo

    2008-01-01

    The model checking problem for open systems has been intensively studied in the literature, for both finite-state (module checking) and infinite-state (pushdown module checking) systems, with respect to Ctl and Ctl*. In this paper, we further investigate this problem with respect to the Mu-calculus enriched with nominals and graded modalities (hybrid graded Mu-calculus), in both the finite-state and infinite-state settings. Using an automata-theoretic approach, we show that hybrid graded Mu-calculus module checking is solvable in exponential time, while hybrid graded Mu-calculus pushdown module checking is solvable in double-exponential time. These results are also tight since they match the known lower bounds for Ctl. We also investigate the module checking problem with respect to the hybrid graded Mu-calculus enriched with inverse programs (Fully enriched Mu-calculus): by showing a reduction from the domino problem, we show its undecidability. We conclude with a short overview of the model checking problem ...

  3. Enriched $^{82}$Se for the LUCIFER experiment

    Beeman, J W; Benetti, P; Cardani, L; Casali, N; Chiesa, D; Clemenza, M; Dafinei, I; Di Domizio, S; Ferroni, F; Gironi, L; Giuliani, A; Gotti, C; Laubenstein, M; Maino, M; Nagorny, S; Nisi, S; Nones, C; Orio, F; Pagnanini, L; Pattavina, L; Pessina, G; Piperno, G; Pirro, S; Previtali, E; Rusconi, C; Schäffner, K; Tomei, C; Vignati, M

    2015-01-01

    The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of $^{82}$Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched $^{82}$Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3% enriched $^{82}$Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of $^{232}$Th, $^{238}$U and $^{235}$U are respectively: $<$61 $\\mu$Bq/kg, $<$110 $\\mu$Bq/kg and $<$74 $\\mu$Bq/kg at 90% C.L.. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the $^{82}$...

  4. Inhomogeneous chemical enrichment in the Galactic Halo

    Kobayashi, Chiaki

    2016-08-01

    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 originate 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 relation. 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 branch stars or neutron star mergers can contribute at low metallicities. The intrinsic variation of yields are important in the early Universe or metal-poor systems such as in the Galactic halo. The carbon enhancement of extremely metal-poor (EMP) stars can be best explained by faint supernovae, the low [α/Fe] ratios in some EMP stars naturally arise from low-mass (~ 13 - 15M ⊙) supernovae, and finally, the [α/Fe] knee in dwarf spheroidal galaxies can be produced by subclasses of Type Ia supernovae such as SN 2002cx-like objects and sub-Chandrasekhar mass explosions.

  5. Supply of enriched uranium for research reactors

    Mueller, H. [NUKEM GmbH, Alzenau (Germany)

    1997-08-01

    Since the RERTR-meeting In Newport/USA in 1990 the author delivered a series of papers in connection with the fuel cycle for research reactors dealing with its front-end. In these papers the author underlined the need for unified specifications for enriched uranium metal suitable for the production of fuel elements and made proposals with regard to the re-use of in Europe reprocessed highly enriched uranium. With regard to the fuel cycle of research reactors the research reactor community was since 1989 more concentrating on the problems of its back-end since the USA stopped the acceptance of spent research reactor fuel on December 31, 1988. Now, since it is apparent that these back-end problem have been solved by AEA`s ability to reprocess and the preparedness of the USA to again accept physically spent research reactor fuel the author is focusing with this paper again on the front-end of the fuel cycle on the question whether there is at all a safe supply of low and high enriched uranium for research reactors in the future.

  6. Evaluation and comparison of rapid methods for the detection of Salmonella in naturally contaminated pine nuts using different pre enrichment media.

    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 μL of pre enrichment, was as effective as manual extraction methods.

  7. A Resolution of the Paradox of Enrichment

    Feng, Z. C.; Li, Y. Charles

    2015-06-01

    The paradox of enrichment was observed by Rosenzweig [1971] in a class of predator-prey models. Two of the parameters in the models are crucial for the paradox. These two parameters are the prey's carrying capacity and prey's half-saturation for predation. Intuitively, increasing the carrying capacity due to enrichment of the prey's environment should lead to a more stable predator-prey system. Analytically, it turns out that increasing the carrying capacity always leads to an unstable predator-prey system that is susceptible to extinction from environmental random perturbations. This is the so-called paradox of enrichment. Our resolution here rests upon a closer investigation on a dimensionless number H formed from the carrying capacity and the prey's half-saturation. By recasting the models into dimensionless forms, the models are in fact governed by a few dimensionless numbers including H. The effects of the two parameters: carrying capacity and half-saturation are incorporated into the number H. In fact, increasing the carrying capacity is equivalent (i.e. has the same effect on H) to decreasing the half-saturation which implies more aggressive predation. Since there is no paradox between more aggressive predation and instability of the predator-prey system, the paradox of enrichment is resolved. The so-called instability of the predator-prey system is characterized by the existence of a stable limit cycle in the phase plane, which gets closer and closer to the predator axis and prey axis. Due to random environmental perturbations, this can lead to extinction. We also further explore spatially dependent models for which the phase space is infinite-dimensional. The spatially independent limit cycle which is generated by a Hopf bifurcation from an unstable steady state, is linearly stable in the infinite-dimensional phase space. Numerical simulations indicate that the basin of attraction of the limit cycle is riddled. This shows that spatial perturbations can

  8. A combined enrichment and aptamer pulldown assay for Francisella tularensis detection in food and environmental matrices.

    Elise A Lamont

    Full Text Available Francisella tularensis, a Gram-negative bacterium and causative agent of tularemia, is categorized as a Class A select agent by the Centers for Disease Control and Prevention due to its ease of dissemination and ability to cause disease. Oropharyngeal and gastrointestinal tularemia may occur due to ingestion of contaminated food and water. Despite the concern to public health, little research is focused on F. tularensis detection in food and environmental matrices. Current diagnostics rely on host responses and amplification of F. tularensis genetic elements via Polymerase Chain Reaction; however, both tools are limited by development of an antibody response and limit of detection, respectively. During our investigation to develop an improved culture medium to aid F. tularensis diagnostics, we found enhanced F. tularensis growth using the spent culture filtrate. Addition of the spent culture filtrate allowed for increased detection of F. tularensis in mixed cultures of food and environmental matrices. Ultraperformance liquid chromatography (UPLC/MS analysis identified several unique chemicals within the spent culture supernatant of which carnosine had a matching m/z ratio. Addition of 0.625 mg/mL of carnosine to conventional F. tularensis medium increased the growth of F. tularensis at low inoculums. In order to further enrich F. tularensis cells, we developed a DNA aptamer cocktail to physically separate F. tularensis from other bacteria present in food and environmental matrices. The combined enrichment steps resulted in a detection range of 1-106 CFU/mL (starting inoculums in both soil and lettuce backgrounds. We propose that the two-step enrichment process may be utilized for easy field diagnostics and subtyping of suspected F. tularensis contamination as well as a tool to aid in basic research of F. tularensis ecology.

  9. SLAM-enriched hematopoietic stem cells maintain long-term repopulating capacity after lentiviral transduction using an abbreviated protocol.

    Laje, P; Zoltick, P W; Flake, A W

    2010-03-01

    Gene transfer to long-term repopulating hematopoietic stem cells (HSCs) using integrating viral vectors is an important goal in gene therapy. The SLAM (signaling lymphocyte activation molecule)-family receptors have recently been used for the isolation of highly enriched murine HSCs. This HSC enrichment protocol is relatively simple, and results in an HSC population with comparable repopulating capacity to c-kit(+)lin(-)Sca-1(+) (KSL) HSCs. The capacity to withstand genetic manipulation and, most importantly, to maintain long-term repopulating capacity of SLAM-enriched HSC populations has not been reported. In this study, SLAM-enriched HSCs were assessed for transduction efficiency and in vivo long-term repopulating capacity after lentiviral transduction using an abbreviated transduction protocol and KSL-enriched HSCs as a reference population. SLAM- and KSL-enriched HSCs were efficiently transduced by lentiviral vector using a simple protocol that involves minimal in vitro manipulation and no pre-stimulation. SLAM-HSCs are at least equal to KSL-HSCs with respect to efficiency of transduction and maintenance of long-term repopulating capacity. Although there was a reduction in repopulating capacity related to enrichment and culture manipulations relative to freshly isolated bone marrow (BM) cells, no detrimental effects were identified on long-term competitive capacity related to transduction, as transduced cells maintained stable levels of chimerism in competition with non-transduced cells and freshly isolated BM cells. These results support the SLAM-HSC enrichment protocol as a simple and efficient method for HSC enrichment for gene transfer studies.

  10. A pre-enrichment step is essential for detection of Campylobacter sp. in turbid pond water.

    Abulreesh, H H; Paget, T A; Goulder, R

    2014-06-01

    This work aimed to detect Campylobacter species from naturally contaminated turbid pond water by PCR. A total of 16 water samples were collected from a turbid village pond. Four methods of DNA extraction were applied to centrifuge pellets from eight 100 ml pond water samples prior to attempted detection of Campylobacter by PCR without an enrichment step. These methods were (1) Tris-HCl and sodium dodecyl sulfate followed by phenol:chloroform:isoamylalcohol extraction followed by treatment with DNA clean up kit, (2) proteinase K, (3) Chelex® 100, and (4) boiling. The other eight pond water samples (10 ml and 100 ml) were filtered and filters were incubated overnight in Preston enrichment broth. The centrifuge pellets obtained from enrichment cultures were treated by proteinase K for DNA extraction. Primers CF03 and CF04 for the flagellin genes (flaA and flaB) of Campylobacter jejuni and Campylobacter coli were used for amplifying the extracted DNA. The DNA extracted from eight-100 ml pond water samples that were not subject to selective enrichment was never amplified with primers CF03 and CF04, hence Campylobacter was not detected. In contrast, the DNA that was from samples that were subjected to a selective enrichment step in Preston broth prior to PCR assay always gave amplified bands of 340-380 bp, therefore the presence of Campylobacter was confirmed. Detection of campylobacters from naturally contaminated, turbid, environmental water may not be feasible by direct PCR assay because of low numbers and the presence of high concentration of humic matter and other PCR inhibitors. The enrichment of water samples in selective broth, however, facilitated PCR detection of Campylobacter probably by increasing cell number and by diluting PCR inhibitors.

  11. Biomineralization of strontianite(SrCO3) by aerobic microorganisms enriched from rhodoliths

    Kang, S.; Roh, Y.

    2012-12-01

    The transport and fate of trace metals and radionuclides in natural environments are controlled by physical, chemical, and microbiological processes. Especially, microbially induced precipitation of carbonates has drawn much attention in recent decades because of its numerous implications such as atmospheric CO2 fixation through mineral carbonation and solid phase capture of inorganic contaminants. The objectives of this study were to investigate the potential for microbially induced precipitation of strontianite (SrCO3) using microorganisms enriched from rhodoliths and to identify mineralogical characteristics of the precipitates of strontianite. Carbonate forming microorganisms were enriched from rhodoliths, which were sampled at Seogwang-ri coast in the western part of Wu Island, Jeju-do, Korea. Microorganisms enriched from rhodoliths were aerobically cultured at 25Ć in D-1 media containing 30 mM Sr-acetate, and the microorganisms were analyzed by 16S rRNA gene DGGE analysis to confirm microbial diversity. Mineralogical characteristics of the carbonate minerals precipitated by the enriched microorganisms were determined by XRD, TEM-EDS, and SEM-EDS analyses. A 16S rRNA sequence analysis showed the enriched microorganisms contained carbonate forming microorganisms such as Proteus mirailis. The enriched microorganisms precipitated carbonate minerals using D-1 media containing 30 mM Sr-acetate and mineralogy of the precipitate was strontianite (SrCO3). SEM/TEM-EDS analyses showed that the strontianite formed by the microorganisms had a spherical shape and consisted of mainly Sr, O and C. TEM-EDS analyses showed that the strontianite formed by the microorganisms had a rhombohedron shape and consisted of mainly Sr, O and C. These results indicate that the microorganisms induce precipitation of strontianite (SrCO3) on the cell walls and EPS via the accumulation of Sr ions on the cells. Therefore, microbial precipitation of carbonate minerals may play one of important

  12. 21 CFR 139.122 - Enriched nonfat milk macaroni products.

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Enriched nonfat milk macaroni products. 139.122... Macaroni and Noodle Products § 139.122 Enriched nonfat milk macaroni products. (a) Each of the enriched macaroni products made with nonfat milk for which a definition and standard of identity is prescribed...

  13. 78 FR 75579 - Low Enriched Uranium From France

    2013-12-12

    ... COMMISSION Low Enriched Uranium From France Determination On the basis of the record \\1\\ developed in the... antidumping duty order on low enriched uranium from France would be likely to lead to continuation or...), entitled Low Enriched Uranium from France: Investigation No. 731-TA-909 (Second Review). By order of...

  14. 31 CFR 540.308 - Low Enriched Uranium (LEU).

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Low Enriched Uranium (LEU). 540.308... OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.308 Low Enriched Uranium (LEU). The term low...

  15. 31 CFR 540.306 - Highly Enriched Uranium (HEU).

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Highly Enriched Uranium (HEU). 540...) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.306 Highly Enriched Uranium (HEU). The term...

  16. Spatial Culture

    Reeh, Henrik

    2012-01-01

    for re-subjectivization. By developing a dialogue with other disciplines, such as the conception of architecture outlined by Alberto Pérez-Gómez, humanistic urban studies may even contribute to reappropriations of objective culture. During the first decade of the 2000s, graduate students at the Faculty......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 illustrations of these major philosophical concepts. Earlier, in the history of critical studies, the work...

  17. Culture Shock

    宋文玲

    2004-01-01

    Specialists say that it is not easy to get used to life in a new culture.“Culture shock”is the term these specialists use when talking about the feelings that people have in a new environment.There are three stages of culture shock,say the specialists.In the first stage,the newcomers like their new environment,Then when the fresh experience

  18. Skin or nail culture

    Mucosal culture; Culture - skin; Culture - mucosal; Nail culture; Culture - fingernail; Fingernail culture ... There, it is placed in a special dish (culture). It is then watched to see if bacteria, ...

  19. A protocol for isolation and enriched monolayer cultivation of neural precursor cells from mouse dentate gyrus

    Harish eBabu

    2011-07-01

    Full Text Available 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 propagate them as adherent monolayer cultures. The strategy is based on the use of Percoll density gradient centrifugation to enrich precursor cells from the micro-dissected dentate gyrus. Based on the expression of Nestin and Sox2, a culture-purity of more than 98% can be achieved. The cultures are expanded under serum-free conditions in Neurobasal A medium with addition of the mitogens EGF and FGF2 as well as the supplements Glutamax-1 and B27. Under differentiation conditions, the precursor cells reliably generate approximately 30% neurons with appropriate morphological, molecular and electrophysiological characteristics that might reflect granule cell properties as their in vivo counterpart. We also highlight potential modifications to the protocol.

  20. Work-family enrichment and psychological health

    Ameeta Jaga

    2013-03-01

    Full Text Available Orientation: This study examines the beneficial aspects of the interface between work and family and its relationships with psychological health from a positive psychology perspective.Research purpose: The objective of this study was to investigate whether work-family enrichment helps to predict psychological health, specifically increased subjective well-being and decreased feelings of emotional exhaustion and depression.Motivation for the study: The burgeoning literature on the work-family interface contains little on the potentially positive benefits of maintaining work and family roles.Research approach, design and method: The authors used a descriptive research design. Employees in two national organisations in the financial retail and logistics industries completed a self-administered survey questionnaire. The authors analysed responses from those who reported both family and work responsibilities (N = 160.Main findings: Consistent with previous research, factor analysis revealed two distinct directions of work-family enrichment: from work to family (W2FE and from family to work (F2WE. Multiple regression analysis showed that F2WE explained a significant proportion of the variance in subjective wellbeing, whilst W2FE explained a significant proportion of the variance in depression and emotional exhaustion.Practical/managerial implications: The findings of this study revealed the individual and organisational benefits of fostering work-family enrichment. Contributions/value add: This study presents empirical evidence for the need to focus on the positive aspects of the work-family interface, provides further support for a positive organisational psychology perspective in organisations and hopefully will encourage further research on interventions in organisations and families.

  1. Modeling Profiles and Signatures of Enrichments

    Ali, A.; Qualls, C.; Lucas, S. G.; Lombari, G.; Appenzeller, O.

    2014-12-01

    Anthropogenic and geochemical enrichment of soils and living matter have been well documented 1, 2, 3.Here we report on geochemical, anthropogenic and biological enrichments with heavy metals in Modern Peru and compared this to Modern and ancient data from New Mexico, USA. We established a signature derived from the quantities of 25 metals in various biological, fossil and soil materials. We also speculate that human adaptation to mercury toxicity may occur in remarkably short time spans during the Holocene. We found mercury concentrations in Modern pigeon feathers and llama wool from free foraging birds and animals in Albuquerque, NM, ranging from 0.006 to 0.019 mg/Kg of tissue. The values for Modern Peru ranged from 22.0 to 556 mg/Kg for the same tissues. We discovered, in 64 million-year-old fossilized plants from New Mexico (Paleocene Nacimiento Formation, San Juan Basin), a mercury concentration of 1.11 mg/Kg of fossil, whereas Modern plant material from the Rio Grande Basin in New Mexico contained no mercury. Profiling of metal content of these samples suggests that mercury is a proxy for anthropogenic rather than geochemical enrichment in the localities we examined. We found no overt signs of mercury toxicity in contemporaneous inhabitants of Huancavelica4, Peru; one of the ten most mercury-polluted places in the world and the mercury concentration in their hair is well below modern admissible levels. However, assessment of their annual scalp hair growth-rate showed marked reduction in growth (~ 5cm/yr) versus ~ 16cm/year for normal scalp hair from other continents4. This is consistent with a toxic effect of heavy metals on human metabolism and especially autonomic nervous system function in Huancavelica, Peru. Contemporaneous anthropogenic activities are known to increase heavy metal content in the biosphere with potentially toxic effects on humans. However, signs of human evolutionary adaptation to such toxins might already be evident in Peru4.

  2. Nitrogen enrichment regulates calcium sources in forests

    Hynicka, Justin D.; Pett-Ridge, Julie C; Perakis, Steven

    2016-01-01

    Nitrogen (N) is a key nutrient that shapes cycles of other essential elements in forests, including calcium (Ca). When N availability exceeds ecosystem demands, excess N can stimulate Ca leaching and deplete Ca from soils. Over the long term, these processes may alter the proportion of available Ca that is derived from atmospheric deposition vs. bedrock weathering, which has fundamental consequences for ecosystem properties and nutrient supply. We evaluated how landscape variation in soil N, reflecting long-term legacies of biological N fixation, influenced plant and soil Ca availability and ecosystem Ca sources across 22 temperate forests in Oregon. We also examined interactions between soil N and bedrock Ca using soil N gradients on contrasting basaltic vs. sedimentary bedrock that differed 17-fold in underlying Ca content. We found that low-N forests on Ca-rich basaltic bedrock relied strongly on Ca from weathering, but that soil N enrichment depleted readily weatherable mineral Ca and shifted forest reliance toward atmospheric Ca. Forests on Ca-poor sedimentary bedrock relied more consistently on atmospheric Ca across all levels of soil N enrichment. The broad importance of atmospheric Ca was unexpected given active regional uplift and erosion that are thought to rejuvenate weathering supply of soil minerals. Despite different Ca sources to forests on basaltic vs. sedimentary bedrock, we observed consistent declines in plant and soil Ca availability with increasing N, regardless of the Ca content of underlying bedrock. Thus, traditional measures of Ca availability in foliage and soil exchangeable pools may poorly reflect long-term Ca sources that sustain soil fertility. We conclude that long-term soil N enrichment can deplete available Ca and cause forests to rely increasingly on Ca from atmospheric deposition, which may limit ecosystem Ca supply in an increasingly N-rich world.

  3. Nitrogen enrichment regulates calcium sources in forests.

    Hynicka, Justin D; Pett-Ridge, Julie C; Perakis, Steven S

    2016-12-01

    Nitrogen (N) is a key nutrient that shapes cycles of other essential elements in forests, including calcium (Ca). When N availability exceeds ecosystem demands, excess N can stimulate Ca leaching and deplete Ca from soils. Over the long term, these processes may alter the proportion of available Ca that is derived from atmospheric deposition vs. bedrock weathering, which has fundamental consequences for ecosystem properties and nutrient supply. We evaluated how landscape variation in soil N, reflecting long-term legacies of biological N fixation, influenced plant and soil Ca availability and ecosystem Ca sources across 22 temperate forests in Oregon. We also examined interactions between soil N and bedrock Ca using soil N gradients on contrasting basaltic vs. sedimentary bedrock that differed 17-fold in underlying Ca content. We found that low-N forests on Ca-rich basaltic bedrock relied strongly on Ca from weathering, but that soil N enrichment depleted readily weatherable mineral Ca and shifted forest reliance toward atmospheric Ca. Forests on Ca-poor sedimentary bedrock relied more consistently on atmospheric Ca across all levels of soil N enrichment. The broad importance of atmospheric Ca was unexpected given active regional uplift and erosion that are thought to rejuvenate weathering supply of soil minerals. Despite different Ca sources to forests on basaltic vs. sedimentary bedrock, we observed consistent declines in plant and soil Ca availability with increasing N, regardless of the Ca content of underlying bedrock. Thus, traditional measures of Ca availability in foliage and soil exchangeable pools may poorly reflect long-term Ca sources that sustain soil fertility. We conclude that long-term soil N enrichment can deplete available Ca and cause forests to rely increasingly on Ca from atmospheric deposition, which may limit ecosystem Ca supply in an increasingly N-rich world.

  4. A metaphor-enriched social cognition.

    Landau, Mark J; Meier, Brian P; Keefer, Lucas A

    2010-11-01

    Social cognition is the scientific study of the cognitive events underlying social thought and attitudes. Currently, the field's prevailing theoretical perspectives are the traditional schema view and embodied cognition theories. Despite important differences, these perspectives share the seemingly uncontroversial notion that people interpret and evaluate a given social stimulus using knowledge about similar stimuli. However, research in cognitive linguistics (e.g., Lakoff & Johnson, 1980) suggests that people construe the world in large part through conceptual metaphors, which enable them to understand abstract concepts using knowledge of superficially dissimilar, typically more concrete concepts. Drawing on these perspectives, we propose that social cognition can and should be enriched by an explicit recognition that conceptual metaphor is a unique cognitive mechanism that shapes social thought and attitudes. To advance this metaphor-enriched perspective, we introduce the metaphoric transfer strategy as a means of empirically assessing whether metaphors influence social information processing in ways that are distinct from the operation of schemas alone. We then distinguish conceptual metaphor from embodied simulation--the mechanism posited by embodied cognition theories--and introduce the alternate source strategy as a means of empirically teasing apart these mechanisms. Throughout, we buttress our claims with empirical evidence of the influence of metaphors on a wide range of social psychological phenomena. We outline directions for future research on the strength and direction of metaphor use in social information processing. Finally, we mention specific benefits of a metaphor-enriched perspective for integrating and generating social cognitive research and for bridging social cognition with neighboring fields.

  5. Cheese bread enriched with biofortified cowpea flour

    Rodrigo Barbosa Monteiro Cavalcante

    2016-02-01

    Full Text Available ABSTRACT The development and enrichment of food are of great importance not only for the industry but also to improve the population's nutrition, where you can create new products or optimize existing ones. The consumption of fortified products in the diet is an option for the control of deficiency diseases. This study aimed to develop enriched cheese bread with whole biofortified cowpea flour and evaluate their acceptance and chemical composition. Two formulations, F1 and F2, were prepared containing 5.6 and 8% of cowpea flour as a substitute for starch, respectively. To check acceptance, three sensory tests were used (Hedonic Scale, Purchase Intent, and Paired Comparison, F1 being sensory viable according to assessors, being chemically analyzed. Minerals were determined by atomic emission spectrometry with inductively coupled plasma source. The moisture was determined by drying at 105 °C, ash by calcination in muffle at 550 °C, proteins by the macro-Kjeldahl method, and lipids by hot extraction in a Soxhlet extractor. Carbohydrates were obtained by difference and the calories were calculated. The addition of cowpea increased the amounts of copper, iron, phosphorus, magnesium, manganese, and zinc, as well as protein and carbohydrate values. On the other hand, there was a reduction of the moisture concerning lipids and the total caloric value compared to the standard formulation. It was concluded , therefore, that the cowpea, a regional raw material in market expansion is presented as an option for the enrichment of baked foods that do not contain gluten, such as cheese bread.

  6. Say Hola: Crossing Borders, Enriching Lives.

    Gates, Michele; Farris, Pamela

    1998-01-01

    Describes a thematic unit of study, carried out in a kindergarten class, on traditional aspects of Mexican life. Describes class activities, unit objectives, and student responses in the unit involving geography, art, literacy, and Mexican culture. (SR)

  7. Enrich the environment to empower the brain.

    Sale, Alessandro; Berardi, Nicoletta; Maffei, Lamberto

    2009-04-01

    Environmental enrichment (EE) has long been exploited to investigate the influence of the environment on brain structure and function. Robust morphological and functional effects elicited by EE at the neuronal level have been reported to be accompanied by improvements in cognitive performance. Recently, EE has been shown to accelerate the development of the visual system and to enhance visual-cortex plasticity in adulthood. These new findings highlight the potential of EE as a promising non-invasive strategy to ameliorate deficits in the maturation of the nervous system and to promote recovery of normal sensory functions in pathological conditions affecting the adult brain.

  8. Enriched vibrational resonance in certain discrete systems

    A Jeevarekha; M Santhiah; P Philominathan

    2014-10-01

    We wish to report the occurrence of vibrational resonance in certain discrete systems like sine square map and sine circle map, in a unique fashion, comprising of multiple resonant peaks which pave the way for enrichment. As the systems of our choice are capable of exhibiting vibrational resonance behaviour unlike the earlier reports, they are taken for investigation and the necessary numerical and analytical results are presented. Further, we study the effect of external forcing on various attractors of these systems with appropriate bifurcation and Lyapunov exponent diagrams.

  9. Enrichment and Preservation of Architectural Knowledge

    Beetz, Jakob; Blümel, Ina; Dietze, Stefan

    2016-01-01

    approaches of semi-automatically deriving building models from point cloud data sets acquired from laser scans and the integration and overlay of such representations with explicit Building Information Models (BIM). We introduce novel ways for the further semantic enrichment of such hybrid building models...... with contextual data and vocabularies from external resources using Linked Data (LD) and the recognition relevant features and building components. A special focus of the research reported here lies on strategies and policies for their long term archival, information retrieval based on rich semantic metadata...

  10. Concise review: no breakthroughs for human mesenchymal and embryonic stem cell culture: conditioned medium, feeder layer, or feeder-free; medium with fetal calf serum, human serum, or enriched plasma; serum-free, serum replacement nonconditioned medium, or ad hoc formula? All that glitters is not gold!

    Mannello, Ferdinando; Tonti, Gaetana A

    2007-07-01

    The choice of an optimal strategy of stem cell culture is at the moment an impossible task, and the elaboration of a culture medium adapted to the production of embryonic and adult mesenchymal stem cells for the clinical application of cell therapy remains a crucial matter. To make an informed choice, it is crucial to not underestimate the theoretical health risk of using xenogenic compounds, to limit the immunological reactions once stem cells are transplanted, to not overestimate the controversial results obtained with human serum, plasma, and blood derivatives, as well as to carefully examine the pros and cons of serum-free and ad hoc formulation strategies; besides that, to also maintain multipotentiality, self-renewal, and transplantability. The extent to which we are able to achieve effective cell therapies will depend on assimilating a rapidly developing base of scientific knowledge with the practical considerations of design, delivery, and host response. Although clinical studies have already started, many questions remain unsolved, and concomitantly even more evidence on suitable and safe off-the-shelf products (mainly xeno-free) for embryonic and mesenchymal stem cells is cropping up, even though there should be no rush to enter the clinical stage while the underlying basic research is still not so solid; this solely will lead to high-quality translational research, without making blunders stemming from the assumption that all that glitters is not gold. Disclosure of potential conflicts of interest is found at the end of this article.

  11. Diversity and enrichment of nitrite-dependent anaerobic methane oxidizing bacteria from wastewater sludge.

    Luesken, Francisca A; van Alen, Theo A; van der Biezen, Erwin; Frijters, Carla; Toonen, Ger; Kampman, Christel; Hendrickx, Tim L G; Zeeman, Grietje; Temmink, Hardy; Strous, Marc; Op den Camp, Huub J M; Jetten, Mike S M

    2011-11-01

    Recently discovered microorganisms affiliated to the bacterial phylum NC10, named "Candidatus Methylomirabilis oxyfera", perform nitrite-dependent anaerobic methane oxidation. These microorganisms could be important players in a novel way of anaerobic wastewater treatment where ammonium and residual dissolved methane might be removed at the expense of nitrate or nitrite. To find suitable inocula for reactor startup, ten selected wastewater treatment plants (WWTPs) located in The Netherlands were screened for the endogenous presence of M. oxyfera using molecular diagnostic methods. We could identify NC10 bacteria with 98% similarity to M. oxyfera in nine out of ten WWTPs tested. Sludge from one selected WWTP was used to start a new enrichment culture of NC10 bacteria. This enrichment was monitored using specific pmoA primers and M. oxyfera cells were visualized with fluorescence oligonucleotide probes. After 112 days, the enrichment consumed up to 0.4 mM NO(2)(-) per day. The results of this study show that appropriate sources of biomass, enrichment strategies, and diagnostic tools existed to start and monitor pilot scale tests for the implementation of nitrite-dependent methane oxidation in wastewater treatment at ambient temperature.

  12. Optimization of STR locus enrichment for STR profiling of fragmented DNA.

    Ham, Seon-Kyu; Kim, Se-Yong; Ahn, Jang-Won; Seo, Bo Young; Woo, Kwang-Man; Choi, Cheol Yong; Lee, Seung-Hwan

    2014-11-01

    DNA degradation is a major obstacle in gaining an accurate profile with standard DNA typing technology. Although alternative genotyping strategies such as mini-STRs and SNPs have proven to be more successful in profiling degraded DNA, these approaches also have limitations. Here, we show that locus enrichment by hybridization of degraded genomic DNA with an STR locus-specific biotinylated oligonucleotide is a powerful approach to overcome problems in STR typing of highly degraded DNA. An experimental investigation of factors affecting the efficiency of this method indicates that the choice of primer and molar ratio of primers to genomic DNA are critical factors in improving enrichment of the STR locus before genotyping with multiplex kits. In addition, we find that indirect capture rather than direct capture with magnetic beads yields better enrichment efficiency for STR locus enrichments. Using these strategies, we demonstrate an improvement in STR typing of DNA from cultured cells damaged by exposure to sunlight or UV. We suggest that this approach could be applied to highly degraded forensic samples alone or in combination with mini-STRs.

  13. [Culturable psychrotolerant methanotrophic bacteria in landfill cover soil].

    Kallistova, A Iu; Montonen, L; Jurgens, G; Munster, U; Kevbrina, M V; Nozhevnikova, A N

    2014-01-01

    Methanotrophs closely related to psychrotolerant members of the genera Methylobacter and Methylocella were identified in cultures enriched at 10@C from landfill cover soil samples collected in the period from April to November. Mesophilic methanotrophs of the genera Methylobacter and Methylosinus were found in cultures enriched at 20 degrees C from the same cover soil samples. A thermotolerant methanotroph related to Methylocaldum gracile was identified in the culture enriched at 40 degrees C from a sample collected in May (the temperature of the cover soil was 11.5-12.5 degrees C). In addition to methanotrophs, methylobacteria of the genera Methylotenera and Methylovorus and members of the genera Verrucomicrobium, Pseudomonas, Pseudoxanthomonas, Dokdonella, Candidatus Protochlamydia, and Thiorhodospira were also identified in the enrichment cultures. A methanotroph closely related to the psychrotolerant species Methylobacter tundripaludum (98% sequence identity of 16S r-RNA genes with the type strain SV96(T)) was isolated in pure culture. The introduction of a mixture of the methanotrophic enrichments, grown at 15 degrees C, into the landfill cover soil resulted in a decrease in methane emission from the landfill surface in autumn (October, November). The inoculum used was demonstrated to contain methanotrophs closely related to Methylobacter tundripaludum SV96.

  14. Cultural Communications.

    Armas, Jose

    It is too often taken for granted that the communication process with culturally different children takes place as readily as it might with children from Anglo cultures. Most teachers receive training in verbal and formal communication skills; children come to school with nonverbal and informal communication skills. This initially can create…

  15. Culture Stories

    Jensen, Ole B.

    2007-01-01

    by certain representations and embedded in certain norms and values. The analytical framework is applied on a case of cultural urban branding. The case is the harbour front in Aalborg, Denmark where a number of flagship architecture projects and cultural institutions are being planned. It is shown how...

  16. Cultural probes

    Madsen, Jacob Østergaard

    2016-01-01

    The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation.......The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation....

  17. Manuscript Cultures

    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...

  18. GOMA: functional enrichment analysis tool based on GO modules

    Qiang Huang; Ling-Yun Wu; Yong Wang; Xiang-Sun Zhang

    2013-01-01

    Analyzing the function of gene sets is a critical step in interpreting the results of high-throughput experiments in systems biology.A variety of enrichment analysis tools have been developed in recent years,but most output a long list of significantly enriched terms that are often redundant,making it difficult to extract the most meaningful functions.In this paper,we present GOMA,a novel enrichment analysis method based on the new concept of enriched functional Gene Ontology (GO) modules.With this method,we systematically revealed functional GO modules,i.e.,groups of functionally similar GO terms,via an optimization model and then ranked them by enrichment scores.Our new method simplifies enrichment analysis results by reducing redundancy,thereby preventing inconsistent enrichment results among functionally similar terms and providing more biologically meaningful results.

  19. CULTURAL TOURISM

    Dana POP

    2016-07-01

    Full Text Available In this paper we will try to analyse the cultural tourism. We will start by referring to the complex concepts of tourism and culture and to the synergies existing between them. We will define cultural tourism and present its appearance and evolution as well as its importance as a modern form of tourism. We will present the various types of cultural tourism with their characteristics and the specific features of cultural tourists according to their interests. We will also mention that there are advantages and disadvantages for any kind of tourism depending on the position – local communities, companies or tourists. For the future we will refer to the new partnership between UNWTO and UNESCO.

  20. Microsatellite DNA capture from enriched libraries.

    Gonzalez, Elena G; Zardoya, Rafael

    2013-01-01

    Microsatellites are DNA sequences of tandem repeats of one to six nucleotides, which are highly polymorphic, and thus the molecular markers of choice in many kinship, population genetic, and conservation studies. There have been significant technical improvements since the early methods for microsatellite isolation were developed, and today the most common procedures take advantage of the hybrid capture methods of enriched-targeted microsatellite DNA. Furthermore, recent advents in sequencing technologies (i.e., next-generation sequencing, NGS) have fostered the mining of microsatellite markers in non-model organisms, affording a cost-effective way of obtaining a large amount of sequence data potentially useful for loci characterization. The rapid improvements of NGS platforms together with the increase in available microsatellite information open new avenues to the understanding of the evolutionary forces that shape genetic structuring in wild populations. Here, we provide detailed methodological procedures for microsatellite isolation based on the screening of GT microsatellite-enriched libraries, either by cloning and Sanger sequencing of positive clones or by direct NGS. Guides for designing new species-specific primers and basic genotyping are also given.