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Sample records for natural bacterioplankton groups

  1. Coastal bacterioplankton community dynamics in response to a natural disturbance.

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    Sara K Yeo

    Full Text Available In order to characterize how disturbances to microbial communities are propagated over temporal and spatial scales in aquatic environments, the dynamics of bacterial assemblages throughout a subtropical coastal embayment were investigated via SSU rRNA gene analyses over an 8-month period, which encompassed a large storm event. During non-perturbed conditions, sampling sites clustered into three groups based on their microbial community composition: an offshore oceanic group, a freshwater group, and a distinct and persistent coastal group. Significant differences in measured environmental parameters or in the bacterial community due to the storm event were found only within the coastal cluster of sampling sites, and only at 5 of 12 locations; three of these sites showed a significant response in both environmental and bacterial community characteristics. These responses were most pronounced at sites close to the shoreline. During the storm event, otherwise common bacterioplankton community members such as marine Synechococcus sp. and members of the SAR11 clade of Alphaproteobacteria decreased in relative abundance in the affected coastal zone, whereas several lineages of Gammaproteobacteria, Betaproteobacteria, and members of the Roseobacter clade of Alphaproteobacteria increased. The complex spatial patterns in both environmental conditions and microbial community structure related to freshwater runoff and wind convection during the perturbation event leads us to conclude that spatial heterogeneity was an important factor influencing both the dynamics and the resistance of the bacterioplankton communities to disturbances throughout this complex subtropical coastal system. This heterogeneity may play a role in facilitating a rapid rebound of regions harboring distinctly coastal bacterioplankton communities to their pre-disturbed taxonomic composition.

  2. Energetic differences between bacterioplankton trophic groups and coral reef resistance.

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    McDole Somera, Tracey; Bailey, Barbara; Barott, Katie; Grasis, Juris; Hatay, Mark; Hilton, Brett J; Hisakawa, Nao; Nosrat, Bahador; Nulton, James; Silveira, Cynthia B; Sullivan, Chris; Brainard, Russell E; Rohwer, Forest

    2016-04-27

    Coral reefs are among the most productive and diverse marine ecosystems on the Earth. They are also particularly sensitive to changing energetic requirements by different trophic levels. Microbialization specifically refers to the increase in the energetic metabolic demands of microbes relative to macrobes and is significantly correlated with increasing human influence on coral reefs. In this study, metabolic theory of ecology is used to quantify the relative contributions of two broad bacterioplankton groups, autotrophs and heterotrophs, to energy flux on 27 Pacific coral reef ecosystems experiencing human impact to varying degrees. The effective activation energy required for photosynthesis is lower than the average energy of activation for the biochemical reactions of the Krebs cycle, and changes in the proportional abundance of these two groups can greatly affect rates of energy and materials cycling. We show that reef-water communities with a higher proportional abundance of microbial autotrophs expend more metabolic energy per gram of microbial biomass. Increased energy and materials flux through fast energy channels (i.e. water-column associated microbial autotrophs) may dampen the detrimental effects of increased heterotrophic loads (e.g. coral disease) on coral reef systems experiencing anthropogenic disturbance. © 2016 The Author(s).

  3. Quantifying the effects of geographical and environmental factors on distribution of stream bacterioplankton within nature reserves of Fujian, China.

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    Wang, Yongming; Yang, Jun; Liu, Lemian; Yu, Zheng

    2015-07-01

    Bacterioplankton are important components of freshwater ecosystems and play essential roles in ecological functions and processes; however, little is known about their geographical distribution and the factors influencing their ecology, especially in stream ecosystems. To examine how geographical and environmental factors affect the composition of bacterioplankton communities, we used denaturing gradient gel electrophoresis and clone sequencing to survey bacterioplankton communities in 31 samples of streamwater from seven nature reserves in Fujian province, southeast China. Our results revealed that dominant bacterioplankton communities exhibited a distinct geographical pattern. Further, we provided evidence for distance decay relationships in bacterioplankton community similarity and found similar community gradients in response to elevation and latitude. Both redundancy analyses and Mantel tests showed that bacterioplankton community composition was significantly correlated with both environmental (electrical conductivity, total phosphorus, and PO4-P) and geographical factors (latitude, longitude, and elevation). Variance partitioning further showed that the joint effect of geographical and environmental factors explained the largest proportion of the variation in distribution of bacterioplankton communities (13.6 %), followed by purely geographical factors (11.2 %), and purely environmental factors (0.6 %). The Betaproteobacteria were the most common taxa in the streams, followed by Firmicutes and Gammaproteobacteria. Therefore, our results suggest that the biogeographical patterns of stream bacterioplankton communities across the Fujian nature reserves are more influenced by geographical factors than by local physicochemical properties.

  4. Latitudinal patterns in the abundance of major marine bacterioplankton groups

    DEFF Research Database (Denmark)

    Wietz, Matthias; Gram, Lone; Jørgensen, Bo

    2010-01-01

    This study describes the abundance of major marine bacterioplankton taxa and two bacterial genera (Pseudoalteromonas and Vibrio) in surface seawater at 24 stations around the world. Catalyzed Reporter Deposition-Fluorescence in situ Hybridization (CARD-FISH) showed that Alphaproteobacteria (average...... relative abundance 37%, average absolute abundance 3.7×105 cells mL-1) including SAR11 (30%/3×105), Gammaproteobacteria (14%/1.2×105), and Bacteroidetes (12%/1.3×105) globally dominated the bacterioplankton. The SAR86 clade (4.6%/4.1×104) and Actinobacteria (4.5%/4×104) were detected ubiquitously, whereas...... Archaea were scarce (0.6%/4.2×103). The Roseobacter clade (averaging 3.8%/3.5×104), Pseudoalteromonas (2.6%/2.1×104), and Vibrio (1.5%/1.3×104) showed cosmopolitan occurrence. Principal Component Analysis revealed a latitudinal pattern in bacterial abundances by clustering samples according to lower...

  5. Comparison of Cellular and Biomass Specific Activities of Dominant Bacterioplankton Groups in Stratified Waters of the Celtic Sea

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    Zubkov, Mikhail V.; Fuchs, Bernhard M.; Burkill, Peter H.; Amann, Rudolf

    2001-01-01

    A flow-sorting technique was developed to determine unperturbed metabolic activities of phylogenetically characterized bacterioplankton groups with incorporation rates of [35S]methionine tracer. According to fluorescence in situ hybridization with rRNA targeted oligonucleotide probes, a clade of α-proteobacteria, related to Roseobacter spp., and a Cytophaga-Flavobacterium cluster dominated the different groups. Cytometric characterization revealed both these groups to have high DNA (HNA) content, while the α-proteobacteria exhibited high light scatter (hs) and the Cytophaga-Flavobacterium cluster exhibited low light scatter (ls). A third abundant group with low DNA (LNA) content contained cells from a SAR86 cluster of γ-proteobacteria. Cellular specific activities of the HNA-hs group were 4- and 1.7-fold higher than the activities in the HNA-ls and LNA groups, respectively. However, the higher cellular protein synthesis by the HNA-hs could simply be explained by their maintenance of a larger cellular protein biomass. Similar biomass specific activities of the different groups strongly support the main assumption that underlies the determination of bacterial production: different bacteria in a complex community incorporate amino acids at a rate proportional to their protein synthesis. The fact that the highest growth-specific rates were determined for the smallest cells of the LNA group can explain the dominance of this group in nutrient-limited waters. The metabolic activities of the three groups accounted for almost the total bacterioplankton activity, indicating their key biogeochemical role in the planktonic ecosystem of the Celtic Sea. PMID:11679347

  6. Natural analogue working group

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.

    1986-01-01

    A Natural Analogue Working Group was established by the Commission of the European Communities in 1985. The purpose of this group is to bring together modellers with earth scientists and others, so that maximum benefit can be obtained from natural analogue studies with a view to safe geological disposal of radioactive waste. The first meeting of this group was held in Brussels from November 5 to 7, 1985. The discussions mainly concerned the identification of the modellers' needs and of the earth scientists' capacity to provide for them. Following the debates, a written statement was produced by the Group; this document forms the core of the present Report. Notes and outlines of many of the presentations made are grouped in four appendixes. The valuable contribution of all those involved in the meeting is gratefully acknowledged

  7. The diversity of the Limnohabitans genus, an important group of freshwater bacterioplankton, by characterization of 35 isolated strains.

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    Vojtěch Kasalický

    Full Text Available Bacteria of the genus Limnohabitans, more precisely the R-BT lineage, have a prominent role in freshwater bacterioplankton communities due to their high rates of substrate uptake and growth, growth on algal-derived substrates and high mortality rates from bacterivory. Moreover, due to their generally larger mean cell volume, compared to typical bacterioplankton cells, they contribute over-proportionally to total bacterioplankton biomass. Here we present genetic, morphological and ecophysiological properties of 35 bacterial strains affiliated with the Limnohabitans genus newly isolated from 11 non-acidic European freshwater habitats. The low genetic diversity indicated by the previous studies using the ribosomal SSU gene highly contrasted with the surprisingly rich morphologies and different patterns in substrate utilization of isolated strains. Therefore, the intergenic spacer between 16S and 23S rRNA genes was successfully tested as a fine-scale marker to delineate individual lineages and even genotypes. For further studies, we propose the division of the Limnohabitans genus into five lineages (provisionally named as LimA, LimB, LimC, LimD and LimE and also additional sublineages within the most diversified lineage LimC. Such a delineation is supported by the morphology of isolated strains which predetermine large differences in their ecology.

  8. The diversity of the Limnohabitans genus, an important group of freshwater bacterioplankton, by characterization of 35 isolated strains

    Czech Academy of Sciences Publication Activity Database

    Kasalický, Vojtěch; Jezbera, Jan; Hahn, M.W.; Šimek, Karel

    2013-01-01

    Roč. 8, č. 3 (2013), e58209 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA206/08/0015; GA ČR(CZ) GAP504/10/0566; GA MŠk(CZ) MEB060702; GA MŠk(CZ) MEB060901 Institutional research plan: CEZ:AV0Z60170517 Institutional support: RVO:60077344 Keywords : bacterial microdiversity * aquatic * Limnohabitans * freshwater * bacterioplankton Subject RIV: EE - Microbiology, Virology Impact factor: 3.534, year: 2013

  9. Maximum growth rates and possible life strategies of different bacterioplankton groups in relation to phosphorus availability in a freshwater reservoir

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Horňák, Karel; Jezbera, Jan; Nedoma, Jiří; Vrba, Jaroslav; Straškrábová, Viera; Macek, Miroslav; Dolan, J. R.; Hahn, M.W.

    2006-01-01

    Roč. 8, č. 9 (2006), s. 1613-1624 ISSN 1462-2912 R&D Projects: GA ČR(CZ) GA206/05/0007; GA AV ČR(CZ) 1QS600170504 Grant - others:MŠM(CZ) 60076658/01 Institutional research plan: CEZ:AV0Z60170517 Keywords : bacterioplankton community composition * growth of bacteria and flagellates * phosphorus availability * reservoir * top-down and bottom-up control Subject RIV: EE - Microbiology, Virology Impact factor: 4.630, year: 2006

  10. Natural variation in SAR11 marine bacterioplankton genomes inferred from metagenomic data

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    Wilhelm Larry J

    2007-11-01

    Full Text Available Abstract Background One objective of metagenomics is to reconstruct information about specific uncultured organisms from fragmentary environmental DNA sequences. We used the genome of an isolate of the marine alphaproteobacterium SAR11 ('Candidatus Pelagibacter ubique'; strain HTCC1062, obtained from the cold, productive Oregon coast, as a query sequence to study variation in SAR11 metagenome sequence data from the Sargasso Sea, a warm, oligotrophic ocean gyre. Results The average amino acid identity of SAR11 genes encoded by the metagenomic data to the query genome was only 71%, indicating significant evolutionary divergence between the coastal isolates and Sargasso Sea populations. However, an analysis of gene neighbors indicated that SAR11 genes in the Sargasso Sea metagenomic data match the gene order of the HTCC1062 genome in 96% of cases (> 85,000 observations, and that rearrangements are most frequent at predicted operon boundaries. There were no conserved examples of genes with known functions being found in the coastal isolates, but not the Sargasso Sea metagenomic data, or vice versa, suggesting that core regions of these diverse SAR11 genomes are relatively conserved in gene content. However, four hypervariable regions were observed, which may encode properties associated with variation in SAR11 ecotypes. The largest of these, HVR2, is a 48 kb region flanked by the sole 5S and 23S genes in the HTCC1062 genome, and mainly encodes genes that determine cell surface properties. A comparison of two closely related 'Candidatus Pelagibacter' genomes (HTCC1062 and HTCC1002 revealed a number of "gene indels" in core regions. Most of these were found to be polymorphic in the metagenomic data and showed evidence of purifying selection, suggesting that the same "polymorphic gene indels" are maintained in physically isolated SAR11 populations. Conclusion These findings suggest that natural selection has conserved many core features of SAR11

  11. Impact of UV Radiation on Bacterioplankton Community Composition†

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    Winter, Christian; Moeseneder, Markus M.; Herndl, Gerhard J.

    2001-01-01

    The potential effect of UV radiation on the composition of coastal marine bacterioplankton communities was investigated. Dilution cultures with seawater collected from the surface mixed layer of the coastal North Sea were exposed to different ranges of natural or artificial solar radiation for up to two diurnal cycles. The composition of the bacterioplankton community prior to exposure was compared to that after exposure to the different radiation regimes using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA and 16S ribosomal DNA. Only minor changes in the composition of the bacterial community in the different radiation regimes were detectable. Sequencing of selected bands obtained by DGGE revealed that some species of the Flexibacter-Cytophaga-Bacteroides (FCB) group were sensitive to UV radiation while other species of the FCB group were resistant. Overall, only up to ≈10% of the operational taxonomic units present in the dilution cultures appeared to be affected by UV radiation. Thus, we conclude that UV radiation has little effect on the composition of coastal marine bacterioplankton communities in the North Sea. PMID:11157229

  12. Distinct Seasonal Patterns of Bacterioplankton Abundance and Dominance of Phyla α-Proteobacteria and Cyanobacteria in Qinhuangdao Coastal Waters Off the Bohai Sea.

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    He, Yaodong; Sen, Biswarup; Zhou, Shuangyan; Xie, Ningdong; Zhang, Yongfeng; Zhang, Jianle; Wang, Guangyi

    2017-01-01

    Qinhuangdao coastal waters in northern China are heavily impacted by anthropogenic and natural activities, and we anticipate a direct influence of the impact on the bacterioplankton abundance and diversity inhabiting the adjacent coastal areas. To ascertain the anthropogenic influences, we first evaluated the seasonal abundance patterns and diversity of bacterioplankton in the coastal areas with varied levels of natural and anthropogenic activities and then analyzed the environmental factors which influenced the abundance patterns. Results indicated distinct patterns in bacterioplankton abundance across the warm and cold seasons in all stations. Total bacterial abundance in the stations ranged from 8.67 × 10 4 to 2.08 × 10 6 cells/mL and had significant ( p bacterioplankton subgroups, α -Proteobacteria (phylum Proteobacteria ) was the dominant one followed by Family II (phylum Cyanobacteria ), representing 19.1-55.2% and 2.3-54.2% of total sequences, respectively. An inverse relationship ( r = -0.82) was observed between the two dominant subgroups, α -Proteobacteria and Family II . A wide range of inverse Simpson index (10.2 to 105) revealed spatial heterogeneity of bacterioplankton diversity likely resulting from the varied anthropogenic and natural influences. Overall, our results suggested that seasonal variations impose substantial influence on shaping bacterioplankton abundance patterns. In addition, the predominance of only a few cosmopolitan species in the Qinhuangdao coastal wasters was probably an indication of their competitive advantage over other bacterioplankton groups in the degradation of anthropogenic inputs. The results provided an evidence of their ecological significance in coastal waters impacted by seasonal inputs of the natural and anthropogenic matter. In conclusion, the findings anticipate future development of effective indicators of coastal health monitoring and subsequent management strategies to control the anthropogenic inputs in

  13. Coastal bacterioplankton community response to diatom-derived polysaccharide microgels.

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    Taylor, Joe D; Cunliffe, Michael

    2017-04-01

    Phytoplankton-derived polysaccharide microgels, including transparent exopolymer particles (TEP), are a major component of the marine organic carbon pool. Previous studies have made correlative links between phytoplankton material and bacterioplankton, and performed experiments that assess general responses to phytoplankton, yet there is a lack of direct empirical evidence of specific bacterioplankton responses to natural phytoplankton polysaccharide microgels. In this study, we used diatom produced TEP in controlled incubation experiments to determine the impact of polysaccharide microgels on a coastal bacterioplankton community. Quantification of bacterial 16S rRNA gene transcripts showed that the addition of TEP caused an increase in bacterioplankton activity. Similarly, high-throughput sequencing of RT-PCR amplified bacterial 16S rRNA gene transcripts showed that active bacterioplankton community structure and diversity also changed in response to microgels. Alteromonadales and Rhodobacterales increased in abundance in response to TEP, suggesting that both bacterioplankton taxa utilize diatom-derived microgels. However, through assessing 13 C-labelled TEP uptake via RNA Stable Isotope Probing, we show that only the Alteromonadales (genus Alteromonas) assimilated the TEP carbon. This study adds utilization of diatom-derived TEP to the metabolic repertoire of the archetypal copiotrophic bacterioplankton Alteromonas, and indicates that the Rhodobacterales may utilize TEP for other purposes (e.g. attachment sites). © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  14. Enhanced viral production and virus-mediated mortality of bacterioplankton in a natural iron-fertilized bloom event above the Kerguelen Plateau

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    Malits, A.; Christaki, U.; Obernosterer, I.; Weinbauer, M. G.

    2014-12-01

    Above the Kerguelen Plateau in the Southern Ocean natural iron fertilization sustains a large phytoplankton bloom over 3 months during austral summer. During the KEOPS1 project (KErguelen Ocean and Plateau compared Study1) we sampled this phytoplankton bloom during its declining phase along with the surrounding high-nutrient-low-chlorophyll (HNLC) waters to study the effect of natural iron fertilization on the role of viruses in the microbial food web. Bacterial and viral abundances were 1.7 and 2.1 times, respectively, higher within the bloom than in HNLC waters. Viral production and virus-mediated mortality of bacterioplankton were 4.1 and 4.9 times, respectively, higher in the bloom, while the fraction of infected cells (FIC) and the fraction of lysogenic cells (FLC) showed no significant differences between environments. The present study suggests viruses to be more important for bacterial mortality within the bloom and dominate over grazing of heterotrophic nanoflagellates (HNFs) during the late bloom phase. As a consequence, at least at a late bloom stage, viral lysis shunts part of the photosynthetically fixed carbon in iron-fertilized regions into the dissolved organic matter (DOM) pool with potentially less particulate organic carbon transferred to larger members of the food web or exported.

  15. Photoheterotrophy of bacterioplankton is ubiquitous in the surface oligotrophic ocean

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    Evans, Claire; Gómez-Pereira, Paola R.; Martin, Adrian P.; Scanlan, David J.; Zubkov, Mikhail V.

    2015-06-01

    Accurate measurements in the Southern Hemisphere were obtained to test a hypothesis of the ubiquity of photoheterotrophy in the oligotrophic ocean. We present experimental results of light-enhanced uptake of methionine, leucine and ATP by bacterioplankton during two large-scale transects of the South Atlantic. Light increased the uptake of substrates by both dominant bacterioplankton groups, Prochlorococcus and SAR11, as well as for the bulk microbial community. Our consistent experimental evidence strongly indicates that photoheterotrophy is characteristic of dominant bacterioplankton populations in the global oligotrophic ocean.

  16. Spatiotemporal pattern of bacterioplankton in Donghu Lake

    Science.gov (United States)

    Zhang, Xiang; Yan, Qingyun; Yu, Yuhe; Dai, Lili

    2014-05-01

    Bacterioplankton play key roles in the biogeochemical cycle and in organic contaminant degradation. The species richness and abundance of bacterial subgroups are generally distinct from each other, and this is attributed to their different functions in aquatic ecosystems. The spatiotemporal variations of eight phylogenetic subgroups (Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, Planctomycetes, alpha-, beta-, and gamma-Proteobacteria) derived from Donghu Lake were investigated using PCR-DGGE fingerprinting, to explore their responses to environmental factors. Results indicate that Actinobacteria and beta-Proteobacteria were the two largest bacterial subgroups detected. These two groups and Bacteroidetes showed clear seasonal patterns in composition of the operational taxonomic unit. Results also suggest that the bacterioplankton subgroups in Donghu Lake were significantly correlated with different environmental factors. In brief, the total nitrogen was one of the major factors regulating all the bacterioplankton except for Actinobacteria. However, total phosphorus, another important eutrophication factor, contributed to the two largest bacterial groups (Actinobacteria and beta-Proteobacteria), as well as to the Cyanobacteria and Firmicutes. Therefore, the responses of bacterioplankton subgroups to environmental factors were different, and this should be attributed to the differences in the functions of different groups.

  17. CEC natural analogue working group

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.A.

    1986-01-01

    The second meeting of the CEC Natural Analogue Working Group took place on June 17-19, 1986, hosted by the Swiss NAGRA in Interlaken (CH). A review of recent progress in natural analogue programmes was carried out, and complemented by detailed discussions about geomicrobiology, archaeological analogues, natural colloids, and use of analogues to increase confidence in safety assessments for radioactive waste disposal. A statement drafted by the Group, and the presentations made, are put together in this report

  18. CEC Natural Analogue Working Group

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.A.

    1989-01-01

    The central theme for the third meeting of the CEC analogue working group was ''How can analogue data be used for performance assessments, both in support of the results and for presentation to the public''. This report puts together the most recent achievements in this field, together with a review of on-going natural analogue programmes

  19. Comparison of Growth Rates of Aerobic Anoxygenic Phototrophic Bacteria and Other Bacterioplankton Groups in Coastal Mediterranean Waters

    Czech Academy of Sciences Publication Activity Database

    Ferrera, I.; Gasol, J.M.; Sebastian, M.; Hojerová, Eva; Koblížek, Michal

    2011-01-01

    Roč. 77, č. 21 (2011), s. 7451-7458 ISSN 0099-2240 R&D Projects: GA ČR GAP501/10/0221 Institutional research plan: CEZ:AV0Z50200510 Keywords : CATALYZED REPORTER DEPOSITION * NATURAL AQUATIC SYSTEMS * IN-SITU HYBRIDIZATION Subject RIV: EE - Microbiology, Virology Impact factor: 3.829, year: 2011

  20. Distinct Seasonal Patterns of Bacterioplankton Abundance and Dominance of Phyla α-Proteobacteria and Cyanobacteria in Qinhuangdao Coastal Waters Off the Bohai Sea

    Directory of Open Access Journals (Sweden)

    Yaodong He

    2017-08-01

    Full Text Available Qinhuangdao coastal waters in northern China are heavily impacted by anthropogenic and natural activities, and we anticipate a direct influence of the impact on the bacterioplankton abundance and diversity inhabiting the adjacent coastal areas. To ascertain the anthropogenic influences, we first evaluated the seasonal abundance patterns and diversity of bacterioplankton in the coastal areas with varied levels of natural and anthropogenic activities and then analyzed the environmental factors which influenced the abundance patterns. Results indicated distinct patterns in bacterioplankton abundance across the warm and cold seasons in all stations. Total bacterial abundance in the stations ranged from 8.67 × 104 to 2.08 × 106 cells/mL and had significant (p < 0.01 positive correlation with total phosphorus (TP, which indicated TP as the key monitoring parameter for anthropogenic impact on nutrients cycling. Proteobacteria and Cyanobacteria were the most abundant phyla in the Qinhuangdao coastal waters. Redundancy analysis revealed significant (p < 0.01 influence of temperature, dissolved oxygen and chlorophyll a on the spatiotemporal abundance pattern of α-Proteobacteria and Cyanobacteria groups. Among the 19 identified bacterioplankton subgroups, α-Proteobacteria (phylum Proteobacteria was the dominant one followed by Family II (phylum Cyanobacteria, representing 19.1–55.2% and 2.3–54.2% of total sequences, respectively. An inverse relationship (r = -0.82 was observed between the two dominant subgroups, α-Proteobacteria and Family II. A wide range of inverse Simpson index (10.2 to 105 revealed spatial heterogeneity of bacterioplankton diversity likely resulting from the varied anthropogenic and natural influences. Overall, our results suggested that seasonal variations impose substantial influence on shaping bacterioplankton abundance patterns. In addition, the predominance of only a few cosmopolitan species in the Qinhuangdao coastal

  1. Consequences of contamination on the interactions between phytoplankton and bacterioplankton.

    Science.gov (United States)

    Marisol, Goni-Urriza; Hélène, Moussard; Céline, Lafabrie; Claire, Carre; Marc, Bouvy; Asma, Sakka Hlaili; Olivier, Pringault

    2018-03-01

    Sediment resuspension can provoke strong water enrichment in nutrients, contaminants, and microorganisms. Microcosm incubations were performed in triplicate for 96 h, with lagoon and offshore waters incubated either with sediment elutriate or with an artificial mixture of contaminants issued from sediment resuspension. Sediment elutriate provoked a strong increase in microbial biomass, with little effects on the phytoplankton and bacterioplankton community structures. Among the pool of contaminants released, few were clearly identified as structuring factors of phytoplankton and bacterioplankton communities, namely simazine, Cu, Sn, Ni, and Cr. Effects were more pronounced in the offshore waters, suggesting a relative tolerance of the lagoon microbial communities to contamination. The impacts of contamination on the microbial community structure were direct or indirect, depending on the nature and the strength of the interactions between phytoplankton and bacterioplankton. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Phytoplankton and bacterioplankton abundances and community dynamics in Lake Erhai.

    Science.gov (United States)

    Mingming, Hu; Yanhui, Li; Yuchun, Wang; Huaidong, Zhou; Yongding, Liu; Gaofeng, Zhao

    2013-01-01

    The composition and seasonal variation of the phytoplankton and bacterioplankton community were investigated, and SPSS and redundancy analysis (RDA) were used to explore the relationship between the phytoplankton and bacterioplankton community dynamics in the typical plateau Lake of Lake Erhai from July 2009 to April 2010. Obvious seasonal variation of phytoplankton was observed, and the abundance of phytoplankton ranged from 2.02 × 10(6) to 57.9 × 10(6) cells/L. The dominant species in autumn and summer was Microcystis sp., Psephonema aenigmaticum Skuja was dominant in winter, and Microcystis sp., Aphanizonmenon flos-aquae, Asterionella sp., P. aenigmaticum, etc. were dominant in spring. The abundance of bacterioplankton in the whole lake changed between 1.93 × 10(9) and 4.61 × 10(9) cells/L showing distinct seasonal variation characteristics. The results of correlation and RDA indicated that the abundance and community diversity of bacterioplankton were significantly correlated with the abundance of phytoplankton, and the group of Bacteroidetes had obvious correlation with Microcystis sp. and other cyanobacteria, which might have some links with the harmful algal blooms in Lake Erhai. Further research is needed to study the mechanisms of interactions between phytoplankton and bacterioplankton communities.

  3. Disentangling seasonal bacterioplankton population dynamics by high-frequency sampling.

    Science.gov (United States)

    Lindh, Markus V; Sjöstedt, Johanna; Andersson, Anders F; Baltar, Federico; Hugerth, Luisa W; Lundin, Daniel; Muthusamy, Saraladevi; Legrand, Catherine; Pinhassi, Jarone

    2015-07-01

    Multiyear comparisons of bacterioplankton succession reveal that environmental conditions drive community shifts with repeatable patterns between years. However, corresponding insight into bacterioplankton dynamics at a temporal resolution relevant for detailed examination of variation and characteristics of specific populations within years is essentially lacking. During 1 year, we collected 46 samples in the Baltic Sea for assessing bacterial community composition by 16S rRNA gene pyrosequencing (nearly twice weekly during productive season). Beta-diversity analysis showed distinct clustering of samples, attributable to seemingly synchronous temporal transitions among populations (populations defined by 97% 16S rRNA gene sequence identity). A wide spectrum of bacterioplankton dynamics was evident, where divergent temporal patterns resulted both from pronounced differences in relative abundance and presence/absence of populations. Rates of change in relative abundance calculated for individual populations ranged from 0.23 to 1.79 day(-1) . Populations that were persistently dominant, transiently abundant or generally rare were found in several major bacterial groups, implying evolution has favoured a similar variety of life strategies within these groups. These findings suggest that high temporal resolution sampling allows constraining the timescales and frequencies at which distinct populations transition between being abundant or rare, thus potentially providing clues about physical, chemical or biological forcing on bacterioplankton community structure. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Detection of marine and freshwater bacterioplankton in immersed victims: Post-mortem bacterial invasion does not readily occur.

    Science.gov (United States)

    Kakizaki, Eiji; Kozawa, Shuji; Imamura, Nahoko; Uchiyama, Taketo; Nishida, Sho; Sakai, Masahiro; Yukawa, Nobuhiro

    2011-09-10

    We previously applied our method of detecting marine or freshwater bacterioplankton (bacteria) in the blood of immersed victims as a marker of drowning. However, we did not confirm the absence of post-mortem bacterial invasion during immersion. Here we examined the nature of bacterioplankton in blood samples from 21 immersed and 4 non-immersed cadavers. We found only freshwater bacterioplankton in the blood of two victims that were retrieved from the sea or an estuary inhabited by marine bacterioplankton even though one victim was highly putrefied. The results of diatom testing suggested that these two victims had drowned in fresh or brackish water with low salinity and then flowed out to the estuary or the sea. Two others were submerged in water, but representative bacterioplankton were undetectable in their blood although one victim was highly putrefied. Autopsy findings and the results of diatom tests did not indicate that the cause of death was drowning. As in previous studies, we identified freshwater bacterioplankton in the blood of seven other victims that had drowned in freshwater, marine bacterioplankton in the blood of four victims that had drowned in seawater and none in four victims found on land that had died by means other than drowning. Bacterioplankton in the blood of drowned victims appears to reflect the type of water aspirated and blood does not become easily contaminated with bacteria post-mortem even in decomposed bodies. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  5. Contrasting diversity of epibiotic bacteria and surrounding bacterioplankton of a common submerged macrophyte, Potamogeton crispus, in freshwater lakes.

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    He, Dan; Ren, Lijuan; Wu, Qinglong L

    2014-12-01

    Epibiotic bacteria on surfaces of submerged macrophytes play important roles in the ecological processes of shallow lakes. However, their community ecology and dynamics are far from understood in comparison with those of bacterioplankton. Here, we conducted a comparative study of the species diversity and composition of epibiotic bacterial and the surrounding bacterioplankton communities of a common submerged macrophyte, Potamogeton crispus, in 12 lakes at a regional scale in China. We found that in different freshwater lakes, epibiotic bacteria possessed higher taxonomic richness than bacterioplankton did. There existed a marked divergence in the community structure between epibiotic bacteria and bacterioplankton. Alphaproteobacteria was the most dominant group for epibiotic bacteria, whereas Actinobacteria dominated bacterioplankton. Although variations in both bacterioplankton and epibiotic bacterial community compositions in different lakes were better explained by environmental than spatial factors, both environment and space had more intensified effects on epibiotic bacteria. This implied more complex and diverse 'microhabitats' for epibiotic bacteria on surfaces of submerged macrophytes, which may lead to higher variations of epibiotic bacteria than bacterioplankton. Our study suggested that epibiotic bacteria exhibited higher diversity and distinct community composition than the surrounding bacterioplankton. More attention should be focused on the productive and diverse microbial habitats on submerged macrophytes. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  6. Elevated pCO2 enhances bacterioplankton removal of organic carbon.

    Science.gov (United States)

    James, Anna K; Passow, Uta; Brzezinski, Mark A; Parsons, Rachel J; Trapani, Jennifer N; Carlson, Craig A

    2017-01-01

    Factors that affect the removal of organic carbon by heterotrophic bacterioplankton can impact the rate and magnitude of organic carbon loss in the ocean through the conversion of a portion of consumed organic carbon to CO2. Through enhanced rates of consumption, surface bacterioplankton communities can also reduce the amount of dissolved organic carbon (DOC) available for export from the surface ocean. The present study investigated the direct effects of elevated pCO2 on bacterioplankton removal of several forms of DOC ranging from glucose to complex phytoplankton exudate and lysate, and naturally occurring DOC. Elevated pCO2 (1000-1500 ppm) enhanced both the rate and magnitude of organic carbon removal by bacterioplankton communities compared to low (pre-industrial and ambient) pCO2 (250 -~400 ppm). The increased removal was largely due to enhanced respiration, rather than enhanced production of bacterioplankton biomass. The results suggest that elevated pCO2 can increase DOC consumption and decrease bacterioplankton growth efficiency, ultimately decreasing the amount of DOC available for vertical export and increasing the production of CO2 in the surface ocean.

  7. Seasonality of freshwater bacterioplankton diversity in two tropical shallow lakes from the Brazilian Atlantic Forest.

    Science.gov (United States)

    Ávila, Marcelo P; Staehr, Peter A; Barbosa, Francisco A R; Chartone-Souza, Edmar; Nascimento, Andréa M A

    2017-01-01

    Bacteria are highly important for the cycling of organic and inorganic matter in freshwater environments; however, little is known about the diversity of bacterioplankton in tropical systems. Studies on carbon and nutrient cycling in tropical lakes suggest a very different seasonality from that of temperate climates. Here, we used 16S rRNA gene next-generation sequencing (NGS) to investigate seasonal changes in bacterioplankton communities of two tropical lakes, which differed in trophic status and mixing regime. Our findings revealed seasonally and depth-wise highly dynamic bacterioplankton communities. Differences in richness and structure appeared strongly related to the physicochemical characteristics of the water column, especially phosphate, pH and oxygen. Bacterioplankton communities were dominated by common taxonomic groups, such as Synechococcus and Actinobacteria acI, as well as rare and poorly characterized taxa such as 'Candidatus Methylacidiphilum' (Verrucomicrobia). Stratification and oxygen depletion during the rainy season promoted the occurrence of anoxygenic phototrophic and methanotrophic bacteria important for carbon and nutrient cycling. Differences in lake mixing regime were associated with seasonal beta diversity. Our study is the first attempt to use NGS for cataloging the diversity of bacterioplankton communities in Brazilian lakes and thus contributes to the ongoing worldwide endeavor to characterize freshwater lake bacterioplankton signatures. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Marine Bacterioplankton Seasonal Succession Dynamics.

    Science.gov (United States)

    Bunse, Carina; Pinhassi, Jarone

    2017-06-01

    Bacterioplankton (bacteria and archaea) are indispensable regulators of global element cycles owing to their unique ability to decompose and remineralize dissolved organic matter. These microorganisms in surface waters worldwide exhibit pronounced seasonal succession patterns, governed by physicochemical factors (e.g., light, climate, and nutrient loading) that are determined by latitude and distance to shore. Moreover, we emphasize that the effects of large-scale factors are modulated regionally, and over shorter timespans (days to weeks), by biological interactions including molecule exchanges, viral lysis, and grazing. Thus the interplay and scaling between factors ultimately determine the success of particular bacterial populations. Spatiotemporal surveys of bacterioplankton community composition provide the necessary frame for interpreting how the distinct metabolisms encoded in the genomes of different bacteria regulate biogeochemical cycles. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Bacterioplankton Community Dynamics and Nutrient Availability in a Shallow Well Mixed Estuary of the Northern Gulf of Mexico.

    Science.gov (United States)

    Hoch, M. P.

    2016-02-01

    Sabine Lake Estuary is a shallow, well mixed, tidal lagoon of the Northern Gulf of Mexico. This study defines the bacterioplankton community composition and factors that may influence its variation in Sabine Lake Estuary. Twenty physicochemical parameters, phytoplankton photopigments, and bacterial 16SrDNA sequences were analyzed seasonally from twelve sites ranging from the inflows of Sabine and Neches Rivers to the Sabine Pass outflow. Photopigments were used to estimate phytoplankton groups via CHEMTAX, and bacterioplankton 16SrDNA sequences of 97% similarity were quantified and taxa identified. Nutrient availability experiments were conducted on bacterioplankton. Notable seasonal differences were seen in six of the ten most common (>3% of total sequences) classes of bacterioplankton. Canonical correspondence analysis (CCA) of common classes was used to explore physiochemical parameters and phytoplankton groups influencing variation in the bacterioplankton. Alphaproteobacteria were most abundant throughout the year. Opitutae, Actinobacteria, Sphingobacteria, and Beta-proteobacteria were strongly influenced by conditions with higher TDN, DOC, turbidity, and Chlorophytes during winter when high river discharges reduced salinity. Planctomycetacia were most prevalent during spring and coincide with predominance of Cryptophytes. In summer and fall the aforementioned classes decline, and there is an increase in Synechococcophycideae. Nitrogen was least available to bacterioplankton during summer and fall. Clearer, warmer and more saline conditions with lower DOC reflect tidal movement of seawater into the estuary when river discharges were low, conditions favorable for Synechococcophycidea. Seasonal fluctuations in physicochemical conditions and certain phytoplankton groups influence the variation in the bacterioplankton community in Sabine Lake Estuary.

  10. The sensitivity and stability of bacterioplankton community structure to wind-wave turbulence in a large, shallow, eutrophic lake.

    Science.gov (United States)

    Zhou, Jian; Qin, Boqiang; Han, Xiaoxia; Jin, Decai; Wang, Zhiping

    2017-12-04

    Lakes are strongly influenced by wind-driven wave turbulence. The direct physical effects of turbulence on bacterioplankton community structure however, have not yet been addressed and remains poorly understood. To examine the stability of bacterioplankton communities under turbulent conditions, we simulated conditions in the field to evaluate the responses of the bacterioplankton community to physical forcing in Lake Taihu, using high-throughput sequencing and flow cytometry. A total of 4,520,231 high quality sequence reads and 74,842 OTUs were obtained in all samples with α-proteobacteria, γ-proteobacteria and Actinobacteria being the most dominant taxa. The diversity and structure of bacterioplankton communities varied during the experiment, but were highly similar based on the same time of sampling, suggesting that bacterioplankton communities are insensitive to wind wave turbulence in the lake. This stability could be associated with the traits associated with bacteria. In particular, turbulence favored the growth of bacterioplankton, which enhanced biogeochemical cycling of nutrients in the lake. This study provides a better understanding of bacterioplankton communities in lake ecosystems exposed to natural mixing/disturbances.

  11. pH influences the importance of niche-related and neutral processes in lacustrine bacterioplankton assembly.

    Science.gov (United States)

    Ren, Lijuan; Jeppesen, Erik; He, Dan; Wang, Jianjun; Liboriussen, Lone; Xing, Peng; Wu, Qinglong L

    2015-05-01

    pH is an important factor that shapes the structure of bacterial communities. However, we have very limited information about the patterns and processes by which overall bacterioplankton communities assemble across wide pH gradients in natural freshwater lakes. Here, we used pyrosequencing to analyze the bacterioplankton communities in 25 discrete freshwater lakes in Denmark with pH levels ranging from 3.8 to 8.8. We found that pH was the key factor impacting lacustrine bacterioplankton community assembly. More acidic lakes imposed stronger environmental filtering, which decreased the richness and evenness of bacterioplankton operational taxonomic units (OTUs) and largely shifted community composition. Although environmental filtering was determined to be the most important determinant of bacterioplankton community assembly, the importance of neutral assembly processes must also be considered, notably in acidic lakes, where the species (OTU) diversity was low. We observed that the strong effect of environmental filtering in more acidic lakes was weakened by the enhanced relative importance of neutral community assembly, and bacterioplankton communities tended to be less phylogenetically clustered in more acidic lakes. In summary, we propose that pH is a major environmental determinant in freshwater lakes, regulating the relative importance and interplay between niche-related and neutral processes and shaping the patterns of freshwater lake bacterioplankton biodiversity. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. Shift in bacterioplankton diversity and structure: Influence of anthropogenic disturbances along the Yarlung Tsangpo River on the Tibetan Plateau, China.

    Science.gov (United States)

    Wang, Peifang; Wang, Xun; Wang, Chao; Miao, Lingzhan; Hou, Jun; Yuan, Qiusheng

    2017-10-02

    River systems have critical roles in the natural water environment and the transportation of nutrients. Anthropogenic activities, including wastewater discharge and river damming, raise adverse impacts on ecosystem and continuum of rivers. An increasing amount of attention has been paid to riverine bacterioplankton as they make vital contributions to biogeochemical nutrient cycle. A comprehensive study was conducted on the bacterioplankton community along the Yarlung Tsangpo River, which is the longest plateau river in China and is suffering from various anthropogenic impacts. The results indicated that nutrient variations corresponded to anthropogenic activities, and silica, nitrogen and phosphorus were retained by the dam. River damming influenced the biomass and diversity of the bacterioplankton, but significant alterations in the community structure were not observed between upstream and downstream of the dam. Moreover, the spatial distribution of the bacterioplankton community changed gradually along the river, and the dominant bacterioplankton in the upstream, midstream and downstream portions of the river were Firmicutes, Bacteroidetes and Proteobacteria, respectively. Soluble reactive phosphorus, elevation, ammonium nitrogen, velocity and turbidity were the main environmental factors that shape the bacterioplankton community. Our study offers the first insights into the variation of a bacterioplankton community of a large river in plateau region.

  13. Effects of temperature and nutrients on changes in genetic diversity of bacterioplankton communities in a semi-closed bay, South Korea.

    Science.gov (United States)

    Kim, Hyun Jung; Jung, Seung Won; Lim, Dhong-Il; Jang, Min-Chul; Lee, Taek-Kyun; Shin, Kyoungsoon; Ki, Jang-Seu

    2016-05-15

    Bacterioplankton communities in a semi-closed bay (Jangmok Bay, South Korea) were analysed using a 16S rDNA multiplex 454 pyrosequencing approach. Diversity and operational taxonomic units of bacterioplankton communities in the Jangmok Bay are highest in cold water seasons and lowest in warm water ones. During cold seasons, α-proteobacteria respond rapidly to pulses of the concentration of inorganic nutrients, while γ-proteobacteria during warm water seasons are the most active type of bacterioplankton resent in the prevailing conditions, which include high dissolved organic carbon, chemical oxygen demand and primary production. Cyanobacteria, a minor group constituting 4.58% of the total bacterioplankton, are more abundant at low temperature. Flavobacteria are more abundant in nutrient-rich conditions and the abundance of this group also demonstrated a delayed decline following summer phytoplankton blooms. The pronounced seasonal oscillations in phosphorus concentration and temperature exert strong selection pressure on bacterioplankton communities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Redox-specialized bacterioplankton metacommunity in a temperate estuary.

    Science.gov (United States)

    Laas, Peeter; Simm, Jaak; Lips, Inga; Lips, Urmas; Kisand, Veljo; Metsis, Madis

    2015-01-01

    This study explored the spatiotemporal dynamics of the bacterioplankton community composition in the Gulf of Finland (easternmost sub-basin of the Baltic Sea) based on phylogenetic analysis of 16S rDNA sequences acquired from community samples via pyrosequencing. Investigations of bacterioplankton in hydrographically complex systems provide good insight into the strategies by which microbes deal with spatiotemporal hydrographic gradients, as demonstrated by our research. Many ribotypes were closely affiliated with sequences isolated from environments with similar steep physiochemical gradients and/or seasonal changes, including seasonally anoxic estuaries. Hence, one of the main conclusions of this study is that marine ecosystems where oxygen and salinity gradients co-occur can be considered a habitat for a cosmopolitan metacommunity consisting of specialized groups occupying niches universal to such environments throughout the world. These niches revolve around functional capabilities to utilize different electron receptors and donors (including trace metal and single carbon compounds). On the other hand, temporal shifts in the bacterioplankton community composition at the surface layer were mainly connected to the seasonal succession of phytoplankton and the inflow of freshwater species. We also conclude that many relatively abundant populations are indigenous and well-established in the area.

  15. Unusual bacterioplankton community structure in ultra-oligotrophic Crater Lake

    Science.gov (United States)

    Urbach, Ena; Vergin, Kevin L.; Morse, Ariel

    2001-01-01

    The bacterioplankton assemblage in Crater Lake, Oregon (U.S.A.), is different from communities found in other oxygenated lakes, as demonstrated by four small subunit ribosomal ribonucleic acid (SSU rRNA) gene clone libraries and oligonucleotide probe hybridization to RNA from lake water. Populations in the euphotic zone of this deep (589 m), oligotrophic caldera lake are dominated by two phylogenetic clusters of currently uncultivated bacteria: CL120-10, a newly identified cluster in the verrucomicrobiales, and ACK4 actinomycetes, known as a minor constituent of bacterioplankton in other lakes. Deep-water populations at 300 and 500 m are dominated by a different pair of uncultivated taxa: CL500-11, a novel cluster in the green nonsulfur bacteria, and group I marine crenarchaeota. b-Proteobacteria, dominant in most other freshwater environments, are relatively rare in Crater Lake (bacterioplankton populations may include low concentrations of available trace metals and dissolved organic matter, chemistry of infiltrating hydrothermal waters, and irradiation by high levels of ultraviolet light.

  16. Thermal discharge-created increasing temperatures alter the bacterioplankton composition and functional redundancy.

    Science.gov (United States)

    Xiong, Jinbo; Xiong, Shangling; Qian, Peng; Zhang, Demin; Liu, Lian; Fei, Yuejun

    2016-12-01

    Elevated seawater temperature has altered the coupling between coastal primary production and heterotrophic bacterioplankton respiration. This shift, in turn, could influence the feedback of ocean ecosystem to climate warming. However, little is known about how natural bacterioplankton community responds to increasing seawater temperature. To investigate warming effects on the bacterioplankton community, we collected water samples from temperature gradients (ranged from 15.0 to 18.6 °C) created by a thermal flume of a coal power plant. The results showed that increasing temperatures significantly stimulated bacterial abundance, grazing rate, and altered bacterioplankton community compositions (BCCs). The spatial distribution of bacterioplankton community followed a distance similarity decay relationship, with a turnover of 0.005. A variance partitioning analysis showed that temperature directly constrained 2.01 % variation in BCCs, while temperature-induced changes in water geochemical and grazing rate indirectly accounted for 4.03 and 12.8 % of the community variance, respectively. Furthermore, the relative abundances of 24 bacterial families were linearly increased or decreased (P < 0.05 in all cases) with increasing temperatures. Notably, the change pattern for a given bacterial family was in concert with its known functions. In addition, community functional redundancy consistently decreased along the temperature gradient. This study demonstrates that elevated temperature, combined with substrate supply and trophic interactions, dramatically alters BCCs, concomitant with decreases in functional redundancy. The responses of sensitive assemblages are temperature dependent, which could indicate temperature departures.

  17. Spatiotemporal distribution of bacterioplankton and bacteriobenthos in the Amur Liman and adjacent sea areas

    Science.gov (United States)

    Karetnikova, E. A.; Garetova, L. A.

    2015-09-01

    Data on the abundance and the ecological-trophic structure of bacterioplankton and bacteriobenthos communities in the Amur Liman and adjacent waters collected in June 2007 have been compared to the relevant data of 2006. Interyear changes of bacterioplankton abundance have been found to depend on the intensity of the Amur River runoff. Correlation analysis has revealed a negative dependence of the abundance of bacterioplankton, bacteriobenthos, and their ecological-trophic groups on water salinity, as well as direct relations between these biotic components and organic matter in water and bottom sediments. The microbiological indicators of water quality ranked the studied waters as classes III-IV in 2006 and as classes II-III in 2007. The high total abundance of bacteriobenthos (109-1010 cells/g) is a result of the functioning of a marginal filter rather than the direct pollution of the liman.

  18. Effects of UV radiation on DNA photodamage and production in bacterioplankton in the coastal Caribbean Sea

    NARCIS (Netherlands)

    Visser, P.M; Snelder, E; Kop, A.J; Boelen, P.; Buma, A.G.J.; van Duyl, F.C

    1999-01-01

    This study focuses on the effects of ultraviolet radiation (UVR) on bacterioplankton. The effect of different parts of the sunlight spectrum on the leucine and thymidine incorporation and on the induction of DNA damage in natural bacterial populations in the coastal Caribbean Sea off Curacao were

  19. Data Sharing & Publishing at Nature Publishing Group

    Science.gov (United States)

    VanDecar, J. C.; Hrynaszkiewicz, I.; Hufton, A. L.

    2015-12-01

    In recent years, the research community has come to recognize that upon-request data sharing has important limitations1,2. The Nature-titled journals feel that researchers have a duty to share data without undue qualifications, in a manner that allows others to replicate and build upon their published findings. Historically, the Nature journals have been strong supporters of data deposition in communities with existing data mandates, and have required data sharing upon request in all other cases. To help address some of the limitations of upon-request data sharing, the Nature titles have strengthened their existing data policies and forged a new partnership with Scientific Data, to promote wider data sharing in discoverable, citeable and reusable forms, and to ensure that scientists get appropriate credit for sharing3. Scientific Data is a new peer-reviewed journal for descriptions of research datasets, which works with a wide of range of public data repositories4. Articles at Scientific Data may either expand on research publications at other journals or may be used to publish new datasets. The Nature Publishing Group has also signed the Joint Declaration of Data Citation Principles5, and Scientific Data is our first journal to include formal data citations. We are currently in the process of adding data citation support to our various journals. 1 Wicherts, J. M., Borsboom, D., Kats, J. & Molenaar, D. The poor availability of psychological research data for reanalysis. Am. Psychol. 61, 726-728, doi:10.1037/0003-066x.61.7.726 (2006). 2 Vines, T. H. et al. Mandated data archiving greatly improves access to research data. FASEB J. 27, 1304-1308, doi:10.1096/fj.12-218164 (2013). 3 Data-access practices strengthened. Nature 515, 312, doi:10.1038/515312a (2014). 4 More bang for your byte. Sci. Data 1, 140010, doi:10.1038/sdata.2014.10 (2014). 5 Data Citation Synthesis Group: Joint Declaration of Data Citation Principles. (FORCE11, San Diego, CA, 2014).

  20. Investigating monsoon and post-monsoon variabilities of bacterioplankton communities in a mangrove ecosystem.

    Science.gov (United States)

    Ghosh, Anwesha; Bhadury, Punyasloke

    2018-02-01

    In mangrove environments, bacterioplankton communities constitute an important component of aquatic biota and play a major role in ecosystem processes. Variability of bacterioplankton communities from Sundarbans mangrove, located in the Indian subcontinent in South Asia and sits on the apex of Bay of Bengal, was investigated over monsoon and post-monsoon seasons. The study was undertaken in two stations in Sundarbans using 16S rRNA clone library and Illumina MiSeq approaches with focus on the functionally important members that participate in coastal biogeochemical cycling. Out of 544 sequenced clones, Proteobacteria dominated the study area (373 sequences) with persistence of two major classes, namely, Gammaproteobacteria and Alphaproteobacteria across both monsoon and post-monsoon seasons in both stations. Several sequences belonging to Sphingomonadales, Chromatiales, Alteromonadales, Oceanospirillales, and Bacteroidetes were encountered that are known to play important roles in coastal carbon cycling. Some sequences showed identity with published uncultured Planctomycetes and Chloroflexi highlighting their role in nitrogen cycling. The detection of two novel clades highlighted the existence of indigenous group of bacterioplankton that may play important roles in this ecosystem. The eubacterial V3-V4 region from environmental DNA extracted from the above two stations, followed by sequencing in Illumina MiSeq system, was also targeted in the study. A congruency between the clone library and Illumina approaches was observed. Strong variability in bacterioplankton community structure was encountered at a seasonal scale in link with precipitation. Drastic increase in sediment associated bacteria such as members of Firmicutes and Desulfovibrio was found in monsoon hinting possible resuspension of sediment-dwelling bacteria into the overlying water column. Principal component analysis (PCA) revealed dissolved ammonium and dissolved nitrate to account for maximum

  1. Proteomic Stable Isotope Probing Reveals Taxonomically Distinct Patterns in Amino Acid Assimilation by Coastal Marine Bacterioplankton.

    Science.gov (United States)

    Bryson, Samuel; Li, Zhou; Pett-Ridge, Jennifer; Hettich, Robert L; Mayali, Xavier; Pan, Chongle; Mueller, Ryan S

    2016-01-01

    Heterotrophic marine bacterioplankton are a critical component of the carbon cycle, processing nearly a quarter of annual primary production, yet defining how substrate utilization preferences and resource partitioning structure microbial communities remains a challenge. In this study, proteomic stable isotope probing (proteomic SIP) was used to characterize population-specific assimilation of dissolved free amino acids (DFAAs), a major source of dissolved organic carbon for bacterial secondary production in aquatic environments. Microcosms of seawater collected from Newport, Oregon, and Monterey Bay, California, were incubated with 1 µM 13 C-labeled amino acids for 15 and 32 h. The taxonomic compositions of microcosm metaproteomes were highly similar to those of the sampled natural communities, with Rhodobacteriales , SAR11, and Flavobacteriales representing the dominant taxa. Analysis of 13 C incorporation into protein biomass allowed for quantification of the isotopic enrichment of identified proteins and subsequent determination of differential amino acid assimilation patterns between specific bacterioplankton populations. Proteins associated with Rhodobacterales tended to have a significantly high frequency of 13 C-enriched peptides, opposite the trend for Flavobacteriales and SAR11 proteins. Rhodobacterales proteins associated with amino acid transport and metabolism had an increased frequency of 13 C-enriched spectra at time point 2. Alteromonadales proteins also had a significantly high frequency of 13 C-enriched peptides, particularly within ribosomal proteins, demonstrating their rapid growth during incubations. Overall, proteomic SIP facilitated quantitative comparisons of DFAA assimilation by specific taxa, both between sympatric populations and between protein functional groups within discrete populations, allowing an unprecedented examination of population level metabolic responses to resource acquisition in complex microbial communities

  2. Inoculation history affects community composition in experimental freshwater bacterioplankton communities.

    Science.gov (United States)

    Rummens, Koen; De Meester, Luc; Souffreau, Caroline

    2018-03-01

    Priority effects occur when the arrival order of species or genotypes has a lasting effect on community or population structure. For freshwater bacteria, priority effects have been shown experimentally among individual species, but no experiments have been performed using complex natural communities. We investigated experimentally whether a foreign bacterioplankton community influences the community assembly trajectory when inoculated prior to the local community, whether inoculation time lag affects priority effects, and how the individual OTUs responded to time lag. Two bacterioplankton communities from dissimilar ponds were inoculated into one of the natural media with a time lag of 0, 12, 36 or 60 h, giving advantage in time to the foreign community. All three time lags resulted in priority effects, as the final community composition of these treatments differed significantly from that of the treatment with no time lag, but compositional shifts were not linear to inoculation time lag. The responses of individual OTUs to time lag were highly diverse and not predictable based on their immigration history or relative abundance in the inocula or control. The observed impact and complexity of priority effects in multispecies systems emphasize the importance of this process in structuring both natural and industrial bacterial communities. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

  3. Fish-mediated changes in bacterioplankton community composition: an in situ mesocosm experiment

    Science.gov (United States)

    Luo, Congqiang; Yi, Chunlong; Ni, Leyi; Guo, Longgen

    2017-06-01

    We characterized variations in bacterioplankton community composition (BCC) in mesocosms subject to three different treatments. Two groups contained fish (group one: Cyprinus carpio; group two: Hypophthalmichthys molitrix); and group three, the untreated mesocosm, was the control. Samples were taken seven times over a 49-day period, and BCC was analyzed by PCR-denaturing gradient gel electrophoresis (DGGE) and real-time quantitative PCR (qPCR). Results revealed that introduction of C. carpio and H. molitrix had a remarkable impact on the composition of bacterioplankton communities, and the BCC was significantly different between each treatment. Sequencing of DGGE bands revealed that the bacterioplankton community in the different treatment groups was consistent at a taxonomic level, but differed in its abundance. H. molitrix promoted the richness of Alphaproteobacteria and Actinobacteria, while more bands affiliated to Cyanobacteria were detected inC. carpio mesocosms. The redundancy analysis (RDA) result demonstrated that the BCC was closely related to the bottom-up (total phosphorus, chlorophyll a, phytoplankton biomass) and top-down forces (biomass of copepods and cladocera) in C. carpio and control mesocosms, respectively. We found no evidence for top-down regulation of BCC by zooplankton in H. molitrix mesocosms, while grazing by protozoa (heterotrophic nanoflagellates, ciliates) became the major way to regulate BCC. Total bacterioplankton abundances were significantly higher in C. carpio mesocosms because of high nutrient concentration and suspended solids. Our study provided insights into the relationship between fish and bacterioplankton at species level, leading to a deep understanding of the function of the microbial loop and the aquatic ecosystem.

  4. Contrasted effects of diversity and immigration on ecological insurance in marine bacterioplankton communities.

    Directory of Open Access Journals (Sweden)

    Thierry Bouvier

    Full Text Available The ecological insurance hypothesis predicts a positive effect of species richness on ecosystem functioning in a variable environment. This effect stems from temporal and spatial complementarity among species within metacommunities coupled with optimal levels of dispersal. Despite its importance in the context of global change by human activities, empirical evidence for ecological insurance remains scarce and controversial. Here we use natural aquatic bacterial communities to explore some of the predictions of the spatial and temporal aspects of the ecological insurance hypothesis. Addressing ecological insurance with bacterioplankton is of strong relevance given their central role in fundamental ecosystem processes. Our experimental set up consisted of water and bacterioplankton communities from two contrasting coastal lagoons. In order to mimic environmental fluctuations, the bacterioplankton community from one lagoon was successively transferred between tanks containing water from each of the two lagoons. We manipulated initial bacterial diversity for experimental communities and immigration during the experiment. We found that the abundance and production of bacterioplankton communities was higher and more stable (lower temporal variance for treatments with high initial bacterial diversity. Immigration was only marginally beneficial to bacterial communities, probably because microbial communities operate at different time scales compared to the frequency of perturbation selected in this study, and of their intrinsic high physiologic plasticity. Such local "physiological insurance" may have a strong significance for the maintenance of bacterial abundance and production in the face of environmental perturbations.

  5. Contrasted Effects of Diversity and Immigration on Ecological Insurance in Marine Bacterioplankton Communities

    Science.gov (United States)

    Bouvier, Corinne; Barbera, Claire; Mouquet, Nicolas

    2012-01-01

    The ecological insurance hypothesis predicts a positive effect of species richness on ecosystem functioning in a variable environment. This effect stems from temporal and spatial complementarity among species within metacommunities coupled with optimal levels of dispersal. Despite its importance in the context of global change by human activities, empirical evidence for ecological insurance remains scarce and controversial. Here we use natural aquatic bacterial communities to explore some of the predictions of the spatial and temporal aspects of the ecological insurance hypothesis. Addressing ecological insurance with bacterioplankton is of strong relevance given their central role in fundamental ecosystem processes. Our experimental set up consisted of water and bacterioplankton communities from two contrasting coastal lagoons. In order to mimic environmental fluctuations, the bacterioplankton community from one lagoon was successively transferred between tanks containing water from each of the two lagoons. We manipulated initial bacterial diversity for experimental communities and immigration during the experiment. We found that the abundance and production of bacterioplankton communities was higher and more stable (lower temporal variance) for treatments with high initial bacterial diversity. Immigration was only marginally beneficial to bacterial communities, probably because microbial communities operate at different time scales compared to the frequency of perturbation selected in this study, and of their intrinsic high physiologic plasticity. Such local “physiological insurance” may have a strong significance for the maintenance of bacterial abundance and production in the face of environmental perturbations. PMID:22701572

  6. Diversity of bacterioplankton in coastal seawaters of Fildes Peninsula, King George Island, Antarctica.

    Science.gov (United States)

    Zeng, Yin-Xin; Yu, Yong; Qiao, Zong-Yun; Jin, Hai-Yan; Li, Hui-Rong

    2014-02-01

    The bacterioplankton not only serves critical functions in marine nutrient cycles, but can also serve as indicators of the marine environment. The compositions of bacterial communities in the surface seawater of Ardley Cove and Great Wall Cove were analyzed using a 16S rRNA multiplex 454 pyrosequencing approach. Similar patterns of bacterial composition were found between the two coves, in which Bacteroidetes, Alphaproteobacteria, and Gammaproteobacteria were the dominant members of the bacterioplankton communities. In addition, a large fraction of the bacterial sequence reads (on average 5.3 % per station) could not be assigned below the domain level. Compared with Ardley Cove, Great Wall Cove showed higher chlorophyll and particulate organic carbon concentrations and exhibited relatively lower bacterial richness and diversity. Inferred metabolisms of summer bacterioplankton in the two coves were characterized by chemoheterotrophy and photoheterotrophy. Results suggest that some cosmopolitan species (e.g., Polaribacter and Sulfitobacter) belonging to a few bacterial groups that usually dominate in marine bacterioplankton communities may have similar ecological functions in similar marine environments but at different geographic locations.

  7. Ubiquity and quantitative significance of bacterioplankton lineages inhabiting the oxygenated hypolimnion of deep freshwater lakes.

    Science.gov (United States)

    Okazaki, Yusuke; Fujinaga, Shohei; Tanaka, Atsushi; Kohzu, Ayato; Oyagi, Hideo; Nakano, Shin-Ichi

    2017-10-01

    The oxygenated hypolimnion accounts for a volumetrically significant part of the global freshwater systems. Previous studies have proposed the presence of hypolimnion-specific bacterioplankton lineages that are distinct from those inhabiting the epilimnion. To date, however, no consensus exists regarding their ubiquity and abundance, which is necessary to evaluate their ecological importance. The present study investigated the bacterioplankton community in the oxygenated hypolimnia of 10 deep freshwater lakes. Despite the broad geochemical characteristics of the lakes, 16S rRNA gene sequencing demonstrated that the communities in the oxygenated hypolimnia were distinct from those in the epilimnia and identified several predominant lineages inhabiting multiple lakes. Catalyzed reporter deposition fluorescence in situ hybridization revealed that abundant hypolimnion-specific lineages, CL500-11 (Chloroflexi), CL500-3, CL500-37, CL500-15 (Planctomycetes) and Marine Group I (Thaumarchaeota), together accounted for 1.5-32.9% of all bacterioplankton in the hypolimnion of the lakes. Furthermore, an analysis of single-nucleotide variation in the partial 16S rRNA gene sequence (oligotyping) suggested the presence of different sub-populations between lakes and water layers among the lineages occurring in the entire water layer (for example, acI-B1 and acI-A7). Collectively, these results provide the first comprehensive overview of the bacterioplankton community in the oxygenated hypolimnion of deep freshwater lakes.

  8. Composition of Total and Cell-Proliferating Bacterioplankton Community in Early Summer in the North Sea - Roseobacters Are the Most Active Component.

    Science.gov (United States)

    Bakenhus, Insa; Dlugosch, Leon; Billerbeck, Sara; Giebel, Helge-Ansgar; Milke, Felix; Simon, Meinhard

    2017-01-01

    Heterotrophic bacterioplankton communities play an important role in organic matter processing in the oceans worldwide. In order to investigate the significance of distinct phylogenetic bacterial groups it is not only important to assess their quantitative abundance but also their growth dynamics in relation to the entire bacterioplankton. Therefore bacterial abundance, biomass production and the composition of the entire and cell-proliferating bacterioplankton community were assessed in North Sea surface waters between the German Bight and 58°N in early summer by applying catalyzed reporter deposition (CARD-FISH) and bromodeoxyuridine fluorescence in situ hybridization (BrdU-FISH). Bacteroidetes and the Roseobacter group dominated the cell-proliferating fraction with 10-55 and 8-31% of total BrdU-positive cells, respectively. While Bacteroidetes also showed high abundances in the total bacterial fraction, roseobacters constituted only 1-9% of all cells. Despite abundances of up to 55% of total bacterial cells, the SAR11 clade constituted bacterioplankton whereas those of the SAR11 clade and Gammaproteobacteria were 0.04 and 0.21 day -1 , respectively, and much lower than bulk growth rates. Only numbers of total and cell-proliferating roseobacters but not those of Bacteroidetes and the other groups were significantly correlated to chlorophyll fluorescence and bacterioplankton biomass production. The Roseobacter group, besides Bacteroidetes , appeared to be a major player in processing phytoplankton derived organic matter despite its low partitioning in the total bacterioplankton community.

  9. Composition of Total and Cell-Proliferating Bacterioplankton Community in Early Summer in the North Sea – Roseobacters Are the Most Active Component

    Science.gov (United States)

    Bakenhus, Insa; Dlugosch, Leon; Billerbeck, Sara; Giebel, Helge-Ansgar; Milke, Felix; Simon, Meinhard

    2017-01-01

    Heterotrophic bacterioplankton communities play an important role in organic matter processing in the oceans worldwide. In order to investigate the significance of distinct phylogenetic bacterial groups it is not only important to assess their quantitative abundance but also their growth dynamics in relation to the entire bacterioplankton. Therefore bacterial abundance, biomass production and the composition of the entire and cell-proliferating bacterioplankton community were assessed in North Sea surface waters between the German Bight and 58°N in early summer by applying catalyzed reporter deposition (CARD-FISH) and bromodeoxyuridine fluorescence in situ hybridization (BrdU-FISH). Bacteroidetes and the Roseobacter group dominated the cell-proliferating fraction with 10–55 and 8–31% of total BrdU-positive cells, respectively. While Bacteroidetes also showed high abundances in the total bacterial fraction, roseobacters constituted only 1–9% of all cells. Despite abundances of up to 55% of total bacterial cells, the SAR11 clade constituted bacterioplankton whereas those of the SAR11 clade and Gammaproteobacteria were 0.04 and 0.21 day-1, respectively, and much lower than bulk growth rates. Only numbers of total and cell-proliferating roseobacters but not those of Bacteroidetes and the other groups were significantly correlated to chlorophyll fluorescence and bacterioplankton biomass production. The Roseobacter group, besides Bacteroidetes, appeared to be a major player in processing phytoplankton derived organic matter despite its low partitioning in the total bacterioplankton community. PMID:28959250

  10. Phylogenetic shifts of bacterioplankton community composition along Pearl Estuary: the potential impact of hypoxia and nutrients

    Directory of Open Access Journals (Sweden)

    Jiwen eLiu

    2015-02-01

    Full Text Available The significance of salinity in shaping bacterial communities dwelling in estuarine areas has been well documented. However, the influences of other environmental factors such as dissolved oxygen and nutrients in governing bacterioplankton communities inhabited in local estuarine regions remain elusive. Here, bacterioplankton community structure of surface and bottom waters from eight sites along Pearl Estuary were characterized with 16S rRNA genes pyrosequencing. The bacterioplankton community dendrogram partitioned the samples into three groups, i.e., whole water column of freshwater sites, surface water of saltwater sites and bottom water of saltwater sites. In the saltwater sites, Synechococcus dominated the surface water while Oceanospirillales, SAR11 and SAR406 were prevalent in the bottom water. Betaproteobacteria was abundant in the freshwater sites, with no significant difference between water layers. Moreover, occurrence of phylogenetic shifts in taxa affiliated to the same clade was also detected. Dissolved oxygen explained most of the bacterial community variation in the redundancy analysis targeting only freshwater sites, whereas nutrients and salinity explained most of the variation across all the samples in Pearl Estuary. Methylophilales (mainly PE2 clade was positively correlated to dissolved oxygen, whereas Rhodocyclales (mainly R.12up clade was negatively correlated. Moreover, high nutrient inputs to the freshwater area of Pearl Estuary have shifted the bacterial communities towards copiotrophic groups, such as Sphingomonadales. The present study provides a clear outline of bacterioplankton communities in two regions of a subtropical estuary and demonstrates that the overall nutrients and freshwater hypoxia play important roles in determining bacterioplankton compositions

  11. An association network analysis among microeukaryotes and bacterioplankton reveals algal bloom dynamics.

    Science.gov (United States)

    Tan, Shangjin; Zhou, Jin; Zhu, Xiaoshan; Yu, Shichen; Zhan, Wugen; Wang, Bo; Cai, Zhonghua

    2015-02-01

    Algal blooms are a worldwide phenomenon and the biological interactions that underlie their regulation are only just beginning to be understood. It is established that algal microorganisms associate with many other ubiquitous, oceanic organisms, but the interactions that lead to the dynamics of bloom formation are currently unknown. To address this gap, we used network approaches to investigate the association patterns among microeukaryotes and bacterioplankton in response to a natural Scrippsiella trochoidea bloom. This is the first study to apply network approaches to bloom dynamics. To this end, terminal restriction fragment (T-RF) length polymorphism analysis showed dramatic changes in community compositions of microeukaryotes and bacterioplankton over the blooming period. A variance ratio test revealed significant positive overall associations both within and between microeukaryotic and bacterioplankton communities. An association network generated from significant correlations between T-RFs revealed that S. trochoidea had few connections to other microeukaryotes and bacterioplankton and was placed on the edge. This lack of connectivity allowed for the S. trochoidea sub-network to break off from the overall network. These results allowed us to propose a conceptual model for explaining how changes in microbial associations regulate the dynamics of an algal bloom. In addition, key T-RFs were screened by principal components analysis, correlation coefficients, and network analysis. Dominant T-RFs were then identified through 18S and 16S rRNA gene clone libraries. Results showed that microeukaryotes clustered predominantly with Dinophyceae and Perkinsea while the majority of bacterioplankton identified were Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes. The ecologi-cal roles of both were discussed in the context of these findings. © 2014 Phycological Society of America.

  12. Interactive network configuration maintains bacterioplankton community structure under elevated CO2 in a eutrophic coastal mesocosm experiment

    Science.gov (United States)

    Lin, Xin; Huang, Ruiping; Li, Yan; Li, Futian; Wu, Yaping; Hutchins, David A.; Dai, Minhan; Gao, Kunshan

    2018-01-01

    There is increasing concern about the effects of ocean acidification on marine biogeochemical and ecological processes and the organisms that drive them, including marine bacteria. Here, we examine the effects of elevated CO2 on the bacterioplankton community during a mesocosm experiment using an artificial phytoplankton community in subtropical, eutrophic coastal waters of Xiamen, southern China. Through sequencing the bacterial 16S rRNA gene V3-V4 region, we found that the bacterioplankton community in this high-nutrient coastal environment was relatively resilient to changes in seawater carbonate chemistry. Based on comparative ecological network analysis, we found that elevated CO2 hardly altered the network structure of high-abundance bacterioplankton taxa but appeared to reassemble the community network of low abundance taxa. This led to relatively high resilience of the whole bacterioplankton community to the elevated CO2 level and associated chemical changes. We also observed that the Flavobacteria group, which plays an important role in the microbial carbon pump, showed higher relative abundance under the elevated CO2 condition during the early stage of the phytoplankton bloom in the mesocosms. Our results provide new insights into how elevated CO2 may influence bacterioplankton community structure.

  13. Decrease of NH4+-N by bacterioplankton accelerated the removal of cyanobacterial blooms in aerated aquatic ecosystem.

    Science.gov (United States)

    Yang, Xi; Xie, Ping; Ma, Zhimei; Wang, Qing; Fan, Huihui; Shen, Hong

    2013-11-01

    We used aerated systems to assess the influence of the bacterioplankton community on cyanobacterial blooms in algae/post-bloom of Lake Taihu, China. Bacterioplankton community diversity was evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting. Chemical analysis and nitrogen dynamic changes illustrated that NH4+-N was nitrified to NO2--N and NO3--N by bacterioplankton. Finally, NH4+-N was exhausted and NO3--N was denitrified to NO2--N, while the accumulation of NO2--N indicated that bacterioplankton with completely aerobic denitrification ability were lacking in the water samples collected from Lake Taihu. We suggested that adding completely aerobic denitrification bacteria (to denitrify NO2--N to N2) would improve the water quality. PCR-DGGE and sequencing results showed that more than1/3 of the bacterial species were associated with the removal of nitrogen, and Acidovorax temperans was the dominant one. PCR-DGGE, variation of nitrogen, removal efficiencies of chlorophyll-a and canonical correspondence analysis indicated that the bacterioplanktonsignificantly influenced the physiological and biochemical changes of cyanobacteria. Additionally, the unweighted pair-group method with arithmetic means revealed there was no obvious harm to the microecosystem from aeration. The present study demonstrated that bacterioplankton can play crucial roles in aerated ecosystems, which could control the impact of cyanobacterial blooms in eutrophicated fresh water systems.

  14. Interactive network configuration maintains bacterioplankton community structure under elevated CO2 in a eutrophic coastal mesocosm experiment

    Directory of Open Access Journals (Sweden)

    X. Lin

    2018-01-01

    Full Text Available There is increasing concern about the effects of ocean acidification on marine biogeochemical and ecological processes and the organisms that drive them, including marine bacteria. Here, we examine the effects of elevated CO2 on the bacterioplankton community during a mesocosm experiment using an artificial phytoplankton community in subtropical, eutrophic coastal waters of Xiamen, southern China. Through sequencing the bacterial 16S rRNA gene V3-V4 region, we found that the bacterioplankton community in this high-nutrient coastal environment was relatively resilient to changes in seawater carbonate chemistry. Based on comparative ecological network analysis, we found that elevated CO2 hardly altered the network structure of high-abundance bacterioplankton taxa but appeared to reassemble the community network of low abundance taxa. This led to relatively high resilience of the whole bacterioplankton community to the elevated CO2 level and associated chemical changes. We also observed that the Flavobacteria group, which plays an important role in the microbial carbon pump, showed higher relative abundance under the elevated CO2 condition during the early stage of the phytoplankton bloom in the mesocosms. Our results provide new insights into how elevated CO2 may influence bacterioplankton community structure.

  15. Alkaline phosphatases in microbialites and bacterioplankton from Alchichica soda lake, Mexico.

    Science.gov (United States)

    Valdespino-Castillo, Patricia M; Alcántara-Hernández, Rocio J; Alcocer, Javier; Merino-Ibarra, Martín; Macek, Miroslav; Falcón, Luisa I

    2014-11-01

    Dissolved organic phosphorus utilization by different members of natural communities has been closely linked to microbial alkaline phosphatases whose affiliation and diversity is largely unknown. Here we assessed genetic diversity of bacterial alkaline phosphatases phoX and phoD, using highly diverse microbial consortia (microbialites and bacterioplankton) as study models. These microbial consortia are found in an oligo-mesotrophic soda lake with a particular geochemistry, exhibiting a low calcium concentration and a high Mg : Ca ratio relative to seawater. In spite of the relative low calcium concentration in the studied system, our results highlight the diversity of calcium-based metallophosphatases phoX and phoD-like in heterotrophic bacteria of microbialites and bacterioplankton, where phoX was the most abundant alkaline phosphatase found. phoX and phoD-like phylotypes were more numerous in microbialites than in bacterioplankton. A larger potential community for DOP utilization in microbialites was consistent with the TN : TP ratio, suggesting P limitation within these assemblages. A cross-system comparison indicated that diversity of phoX in Lake Alchichica was similar to that of other aquatic systems with a naturally contrasting ionic composition and trophic state, although no phylotypes were shared among systems. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  16. The biogeography of abundant and rare bacterioplankton in the lakes and reservoirs of China

    Science.gov (United States)

    Liu, Lemian; Yang, Jun; Yu, Zheng; Wilkinson, David M

    2015-01-01

    Bacteria play key roles in the ecology of both aquatic and terrestrial ecosystems; however, little is known about their diversity and biogeography, especially in the rare microbial biosphere of inland freshwater ecosystems. Here we investigated aspects of the community ecology and geographical distribution of abundant and rare bacterioplankton using high-throughput sequencing and examined the relative influence of local environmental variables and regional (spatial) factors on their geographical distribution patterns in 42 lakes and reservoirs across China. Our results showed that the geographical patterns of abundant and rare bacterial subcommunities were generally similar, and both of them showed a significant distance–decay relationship. This suggests that the rare bacterial biosphere is not a random assembly, as some authors have assumed, and that its distribution is most likely subject to the same ecological processes that control abundant taxa. However, we identified some differences between the abundant and rare groups as both groups of bacteria showed a significant positive relationship between sites occupancy and abundance, but the abundant bacteria exhibited a weaker distance–decay relationship than the rare bacteria. Our results implied that rare subcommunities were mostly governed by local environmental variables, whereas the abundant subcommunities were mainly affected by regional factors. In addition, both local and regional variables that were significantly related to the spatial variation of abundant bacterial community composition were different to those of rare ones, suggesting that abundant and rare bacteria may have discrepant ecological niches and may play different roles in natural ecosystems. PMID:25748371

  17. Oceanic fronts: transition zones for bacterioplankton community composition

    Science.gov (United States)

    Baltar, F.; Currie, K.; Stuck, E.; Roosa, S.; Morales, S.

    2016-02-01

    Oceanic fronts are widespread mesoscale features that exist in the boundary between different water masses. Bacterioplankton (including Bacteria and Archaea) drive oceanic biogeochemical cycles, regulating the composition of Earth's atmosphere and influencing climate. Despite the recognized importance of bacterioplankton on the marine biogeochemical cycles and the ubiquitousness of fronts, the effect of frontal zones on the distribution of bacterioplankton community remains unknown. Using 16S rRNA gene sequencing coupled with a high spatial resolution analysis of the physical properties of the water masses, we demonstrate strong shifts in bacterioplankton community composition (BCC) across the Subtropical Frontal Zone off New Zealand. Transition between water masses resulted in a clear modification of the dominant taxa and a significant increase in community dissimilarity. Our results, linking physical oceanography and marine molecular ecology, support the strong role of oceanic frontal zones in delimiting the distribution of bacterioplankton in the ocean, where fronts serve as clear transition zones, indicating boundaries for bacterioplankton distribution in the ocean. Owing to the widespread abundance of fronts in the marine environment, future efforts should focus on confirming their roles in demarking bacterioplankton distribution and whether they act as indicators of ecosystem process changes. This would allow a better understanding of the forces that control energy flow in the ocean as well as the cycling of compounds that influence climate change, and concomitantly building more accurate models of global biogeochemical cycles.

  18. Covariance of bacterioplankton composition and environmental variables in a temperate delta system

    Science.gov (United States)

    Stepanauskas, R.; Moran, M.A.; Bergamaschi, B.A.; Hollibaugh, J.T.

    2003-01-01

    We examined seasonal and spatial variation in bacterioplankton composition in the Sacramento-San Joaquin River Delta (CA) using terminal restriction fragment length polymorphism (T-RFLP) analysis. Cloned 16S rRNA genes from this system were used for putative identification of taxa dominating the T-RFLP profiles. Both cloning and T-RFLP analysis indicated that Actinobacteria, Verrucomicrobia, Cytophaga-Flavobacterium and Proteobacteria were the most abundant bacterioplankton groups in the Delta. Despite the broad variety of sampled habitats (deep water channels, lakes, marshes, agricultural drains, freshwater and brackish areas), and the spatial and temporal differences in hydrology, temperature and water chemistry among the sampling campaigns, T-RFLP electropherograms from all samples were similar, indicating that the same bacterioplankton phylotypes dominated in the various habitats of the Delta throughout the year. However, principal component analysis (PCA) and partial least-squares regression (PLS) of T-RFLP profiles revealed consistent grouping of samples on a seasonal, but not a spatial, basis. ??-Proteobacteria related to Ralstonia, Actinobacteria related to Microthrix, and ??-Proteobacteria identical to the environmental Clone LD12 had the highest relative abundance in summer/fall T-RFLP profiles and were associated with low river flow, high pH, and a number of optical and chemical characteristics of dissolved organic carbon (DOC) indicative of an increased proportion of phytoplankton-produced organic material as opposed to allochthonous, terrestrially derived organic material. On the other hand, Geobacter-related ??-Proteobacteria showed a relative increase in abundance in T-RFLP analysis during winter/spring, and probably were washed out from watershed soils or sediment. Various phylotypes associated with the same phylogenetic division, based on tentative identification of T-RFLP fragments, exhibited diverse seasonal patterns, suggesting that ecological

  19. Characterization of the bacterioplankton community and its antibiotic resistance genes in the Baltic Sea.

    Science.gov (United States)

    Tiirik, Kertu; Nõlvak, Hiie; Oopkaup, Kristjan; Truu, Marika; Preem, Jens-Konrad; Heinaru, Ain; Truu, Jaak

    2014-01-01

    The residues from human environments often contain antibiotics and antibiotic resistance genes (ARGs) that can contaminate natural environments; the clearest consequence of that is the selection of antibiotic-resistant bacteria. The Baltic Sea is the second largest isolated brackish water reservoir on Earth, serving as a drainage area for people in 14 countries, which differ from one another in antibiotic use and sewage treatment policies. The aim of this study was to characterize the bacterioplankton structure and quantify ARGs (tetA, tetB, tetM, ermB, sul1, blaSHV, and ampC) within the bacterioplankton community of the Baltic Sea. Quantitative polymerase chain reaction was applied to quantify ARGs from four different sampling sites of the Baltic Sea over 2 years, and the bacterial communities were profiled sequencing the V6 region of the 16S rRNA gene on Illumina HiSeq2000. The results revealed that all the resistance genes targeted in the study were detectable from the Baltic Sea bacterioplankton. The percentage of tetA, tetB, tetM, ermB, and sul1 genes in the sea bacterial community varied between 0.0077% and 0.1089%, 0.0003% and 0.0019%, 0.0001% and 0.0105%, 0% and 0.0136%, and 0.0001% and 0.0438%, respectively. The most numerous ARG detected was the tetA gene and this gene also had the highest proportion in the whole microbial community. A strong association between bacterioplankton ARGs' abundance data and community phylogenetic composition was found, implying that the abundance of most of the studied ARGs in the Baltic Sea is determined by fluctuations in its bacterial community structure. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

  20. Bacterioplankton community structure in the Arctic waters as revealed by pyrosequencing of 16S rRNA genes.

    Science.gov (United States)

    Zeng, Yin-Xin; Zhang, Fang; He, Jian-Feng; Lee, Sang H; Qiao, Zong-Yun; Yu, Yong; Li, Hui-Rong

    2013-06-01

    Fjords and open oceans are two typical marine ecosystems in the Arctic region, where glacial meltwater and sea ice meltwater have great effects on the bacterioplankton community structure during the summer season. This study aimed to determine the differences in bacterioplankton communities between these two ecosystems in the Arctic region. We conducted a detailed census of microbial communities in Kongsfjorden (Spitsbergen) and the Chukchi Borderland using high-throughput pyrosequencing of the 16S rRNA gene. Gammaproteobacteria and Bacteroidetes were the dominant members of the bacterioplankton community in Kongsfjorden. By contrast, the most abundant bacterial groups in the surface seawater samples from the Chukchi Borderland were Alphaproteobacteria and Actinobacteria. Differences in bacterial communities were found between the surface and subsurface waters in the investigation area of the Chukchi Borderland, and significant differences in bacterial community structure were also observed in the subsurface water between the shelf and deep basin areas. These results suggest the effect of hydrogeographic conditions on bacterial communities. Ubiquitous phylotypes found in all the investigated samples belonged to a few bacterial groups that dominate marine bacterioplankton communities. The sequence data suggested that changes in environmental conditions result in abundant rare phylotypes and reduced amounts of other phylotypes.

  1. Oceanic fronts: transition zones for bacterioplankton community composition.

    Science.gov (United States)

    Baltar, Federico; Currie, Kim; Stuck, Esther; Roosa, Stéphanie; Morales, Sergio E

    2016-02-01

    Oceanic fronts are widespread mesoscale features that exist in the boundary between different water masses. Despite the recognized importance of bacterioplankton (including bacteria and archaea) on the marine biogeochemical cycles and the ubiquitousness of fronts, the effect of frontal zones on the distribution of bacterioplankton community remains unknown. Using 16S rRNA gene sequencing coupled with a high spatial resolution analysis of the physical properties of the water masses, we demonstrate strong shifts in bacterioplankton community composition (BCC) across the subtropical frontal zone off New Zealand. The transition between water masses resulted in a clear modification of the dominant taxa and a significant increase in community dissimilarity. Our results, linking physical oceanography and marine molecular ecology, support the strong role of oceanic frontal zones in delimiting the distribution of bacterioplankton in the ocean. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  2. BACTERIOPLANKTON DYNAMICS IN A SUBTROPICAL ESTUARY: EVIDENCE FOR SUBSTRATE LIMITATION

    Science.gov (United States)

    Bacterioplankton abundance and metabolic characteristics were measured along a transect in Pensacola Bay, Florida, USA, to examine the factors that control microbial water column processes in this subtropical estuary. The microbial measures included 3 H-L-leucine incorporation, e...

  3. In-group favouritism and out-group discimination in naturally occurring groups

    OpenAIRE

    Donna Harris; Klaus Abbink

    2012-01-01

    We study in-group favouritism and out-group discrimination in a multiplayer dictator game. An allocator divides a large sum of money among three groups of 20 recipients each and Self. Allocations to groups are divided equally among the group members. The three groups are supporters of the two rival political movements in Thailand (“yellow shirts†versus “red shirts†) and political neutral subjects. A control treatment with artificial groups (“group A†, “group B†, and “non-aff...

  4. UK Natural Analogue Coordinating Group: fourth annual report

    International Nuclear Information System (INIS)

    Read, D.; Hooker, P.J.

    1992-01-01

    HMIP has a research programme investigating some naturally radioactive sites as geochemical analogues of radionuclide migration. All of the analogue sites under investigation, both in the U.K. and overseas, are located where elevated uranium concentrations occur naturally. Coordination of the programme is achieved through the UK Natural Analogue Co-ordinating Group (NACG) which has met three times in this reporting period. The NACG is steered by the British Geological Survey. Its purpose is to ensure that the different research projects have an integrated function aimed at increasing our understanding of natural geochemical processes. Effort is also being expended in testing research models which may be used in such assessments. (author)

  5. Analytical group decision making in natural resources: methodology and application

    Science.gov (United States)

    Daniel L. Schmoldt; David L. Peterson

    2000-01-01

    Group decision making is becoming increasingly important in natural resource management and associated scientific applications, because multiple values are treated coincidentally in time and space, multiple resource specialists are needed, and multiple stakeholders must be included in the decision process. Decades of social science research on decision making in groups...

  6. [Effects of sediment resuspension on bacterioplankton community composition].

    Science.gov (United States)

    Guo, Liang; Xing, Peng; Jiang, Wei-wei; Liu, Zheng-wen

    2010-08-01

    To determine the response of bacterioplankton community to sediment resuspension we set up two different intensities of the sediment resuspension in experimental microcosms. We employed the terminal restriction fragment length polymorphism (T-RFLP), denaturing gradient gel electrophoresis (DGGE) methods to characterize the bacterial community structure. The result demonstrated that the species richness of the bacterioplankton in the treatment with sediment resuspension was higher than that in the controls without sediment resuspension. The bacterioplankton species richness and community diversity in the treatment with weak sediment resuspension (WR) was higher than that with strong sediment resuspension (SR). The relationship between bacterioplankton and environmental factors were investigated using canonical correspondence analysis (CCA) and redundancy analysis (RDA). The CCA and RDA results showed that there was a high degree of correlation between bacterioplankton community composition with Cladocera and particulate phosphorus (PP). It indicates that the sediment resuspension of shallow lakes has a significant effect on the species richness and diversity of bacterioplankton. We speculate the main reason is the dynamics of zooplankton community structure and the function of nutrient concentration influenced by the sediment resuspension.

  7. Group decision-making techniques for natural resource management applications

    Science.gov (United States)

    Coughlan, Beth A.K.; Armour, Carl L.

    1992-01-01

    This report is an introduction to decision analysis and problem-solving techniques for professionals in natural resource management. Although these managers are often called upon to make complex decisions, their training in the natural sciences seldom provides exposure to the decision-making tools developed in management science. Our purpose is to being to fill this gap. We present a general analysis of the pitfalls of group problem solving, and suggestions for improved interactions followed by the specific techniques. Selected techniques are illustrated. The material is easy to understand and apply without previous training or excessive study and is applicable to natural resource management issues.

  8. Bacterioplankton of the Kara Sea shelf

    Science.gov (United States)

    Romanova, N. D.; Sazhin, A. F.

    2015-11-01

    The principal zones of the Kara Sea shelf are distinguished on the basis of structural and functional characteristics of bacterioplankton. Estuarine regions are characterized by elevated bacterial abundance and production rates, while the adjacent shelf has high abundance but lower production values. The southwestern part of the Kara Sea has relatively low bacterial abundance; here, the activity of microorganisms depends on the availability of allochthonous organic matter. In the northern part of the Kara Sea shelf, high bacterial abundance and growth rates are observed in the upper brackish water layer. The upper water layer above the slope of the St. Anna Trough is characterized by low numbers of bacteria, and production rates decrease almost to zero values. It has been shown that the analysis of bacterial abundance in the upper mixed layer is enough for the characterization of quantitative changes in bacterial community of the shelf zone.

  9. THE NATURE OF RADICAL ISLAMIC GROUPS IN SOLO

    Directory of Open Access Journals (Sweden)

    Muhammad Wildan

    2013-06-01

    Full Text Available Radical Islamism is a challenging new pheno­menon in the modern world, including Indonesia. Solo presents an especially interesting case because of the dispropor­tionate nature of the radical Islamic groups that have emerged here especially that of the Front Pemuda Islam Surakarta (FPIS as well as other vigilante groups in the city. This paper will explore and map out the nature of Islam in Solo and asks what triggers the the emergence of the radical groups here. Dramatic changes at the national level have made Solo more politically conducive for radical Islamic groups, but this is not the only reason why they have flourished. In addition, historical and sociological factors may help such groups to emerge. Hence, the dominance of the abangan group (the nominal Muslims and the intensity of dakwah (preaching conducted by some Islamic groups has given rise to the ‘instant’ Muslims who see Islam as the ultimate solution to their problems. The call for jihād and the application of sharī‘ah laws are among the contentious political style that the groups propagated. It is these issues that the paper is interested to investigate.

  10. Analytical group decision making in natural resources: Methodology and application

    Science.gov (United States)

    Schmoldt, D.L.; Peterson, D.L.

    2000-01-01

    Group decision making is becoming increasingly important in natural resource management and associated scientific applications, because multiple values are treated coincidentally in time and space, multiple resource specialists are needed, and multiple stakeholders must be included in the decision process. Decades of social science research on decision making in groups have provided insights into the impediments to effective group processes and on techniques that can be applied in a group context. Nevertheless, little integration and few applications of these results have occurred in resource management decision processes, where formal groups are integral, either directly or indirectly. A group decision-making methodology is introduced as an effective approach for temporary, formal groups (e.g., workshops). It combines the following three components: (1) brainstorming to generate ideas; (2) the analytic hierarchy process to produce judgments, manage conflict, enable consensus, and plan for implementation; and (3) a discussion template (straw document). Resulting numerical assessments of alternative decision priorities can be analyzed statistically to indicate where group member agreement occurs and where priority values are significantly different. An application of this group process to fire research program development in a workshop setting indicates that the process helps focus group deliberations; mitigates groupthink, nondecision, and social loafing pitfalls; encourages individual interaction; identifies irrational judgments; and provides a large amount of useful quantitative information about group preferences. This approach can help facilitate scientific assessments and other decision-making processes in resource management.

  11. Insights into bacterioplankton community structure from Sundarbans mangrove ecoregion using Sanger and Illumina MiSeq sequencing approaches: A comparative analysis.

    Science.gov (United States)

    Ghosh, Anwesha; Bhadury, Punyasloke

    2017-03-01

    Next generation sequencing using platforms such as Illumina MiSeq provides a deeper insight into the structure and function of bacterioplankton communities in coastal ecosystems compared to traditional molecular techniques such as clone library approach which incorporates Sanger sequencing. In this study, structure of bacterioplankton communities was investigated from two stations of Sundarbans mangrove ecoregion using both Sanger and Illumina MiSeq sequencing approaches. The Illumina MiSeq data is available under the BioProject ID PRJNA35180 and Sanger sequencing data under accession numbers KX014101-KX014140 (Stn1) and KX014372-KX014410 (Stn3). Proteobacteria-, Firmicutes- and Bacteroidetes-like sequences retrieved from both approaches appeared to be abundant in the studied ecosystem. The Illumina MiSeq data (2.1 GB) provided a deeper insight into the structure of bacterioplankton communities and revealed the presence of bacterial phyla such as Actinobacteria, Cyanobacteria, Tenericutes, Verrucomicrobia which were not recovered based on Sanger sequencing. A comparative analysis of bacterioplankton communities from both stations highlighted the presence of genera that appear in both stations and genera that occur exclusively in either station. However, both the Sanger sequencing and Illumina MiSeq data were coherent at broader taxonomic levels. Pseudomonas , Devosia , Hyphomonas and Erythrobacter- like sequences were the abundant bacterial genera found in the studied ecosystem. Both the sequencing methods showed broad coherence although as expected the Illumina MiSeq data helped identify rarer bacterioplankton groups and also showed the presence of unassigned OTUs indicating possible presence of novel bacterioplankton from the studied mangrove ecosystem.

  12. Insights into bacterioplankton community structure from Sundarbans mangrove ecoregion using Sanger and Illumina MiSeq sequencing approaches: A comparative analysis

    Directory of Open Access Journals (Sweden)

    Anwesha Ghosh

    2017-03-01

    Full Text Available Next generation sequencing using platforms such as Illumina MiSeq provides a deeper insight into the structure and function of bacterioplankton communities in coastal ecosystems compared to traditional molecular techniques such as clone library approach which incorporates Sanger sequencing. In this study, structure of bacterioplankton communities was investigated from two stations of Sundarbans mangrove ecoregion using both Sanger and Illumina MiSeq sequencing approaches. The Illumina MiSeq data is available under the BioProject ID PRJNA35180 and Sanger sequencing data under accession numbers KX014101-KX014140 (Stn1 and KX014372-KX014410 (Stn3. Proteobacteria-, Firmicutes- and Bacteroidetes-like sequences retrieved from both approaches appeared to be abundant in the studied ecosystem. The Illumina MiSeq data (2.1 GB provided a deeper insight into the structure of bacterioplankton communities and revealed the presence of bacterial phyla such as Actinobacteria, Cyanobacteria, Tenericutes, Verrucomicrobia which were not recovered based on Sanger sequencing. A comparative analysis of bacterioplankton communities from both stations highlighted the presence of genera that appear in both stations and genera that occur exclusively in either station. However, both the Sanger sequencing and Illumina MiSeq data were coherent at broader taxonomic levels. Pseudomonas, Devosia, Hyphomonas and Erythrobacter-like sequences were the abundant bacterial genera found in the studied ecosystem. Both the sequencing methods showed broad coherence although as expected the Illumina MiSeq data helped identify rarer bacterioplankton groups and also showed the presence of unassigned OTUs indicating possible presence of novel bacterioplankton from the studied mangrove ecosystem.

  13. Biogeography of bacterioplankton in the tropical seawaters of Singapore.

    Science.gov (United States)

    Lau, Stanley C K; Zhang, Rui; Brodie, Eoin L; Piceno, Yvette M; Andersen, Gary; Liu, Wen-Tso

    2013-05-01

    Knowledge about the biogeography of marine bacterioplankton on the global scale in general and in Southeast Asia in particular has been scarce. This study investigated the biogeography of bacterioplankton community in Singapore seawaters. Twelve stations around Singapore island were sampled on different schedules over 1 year. Using PCR-DNA fingerprinting, DNA cloning and sequencing, and microarray hybridization of the 16S rRNA genes, we observed clear spatial variations of bacterioplankton diversity within the small area of the Singapore seas. Water samples collected from the Singapore Strait (south) throughout the year were dominated by DNA sequences affiliated with Cyanobacteria and Alphaproteobacteria that were believed to be associated with the influx of water from the open seas in Southeast Asia. On the contrary, water in the relatively polluted Johor Strait (north) were dominated by Betaproteobacteria, Gammaproteobacteria, and Bacteroidetes and that were presumably associated with river discharge and the relatively eutrophic conditions of the waterway. Bacterioplankton diversity was temporally stable, except for the episodic surge of Pseudoalteromonas, associated with algal blooms. Overall, these results provide valuable insights into the diversity of bacterioplankton communities in Singapore seas and the possible influences of hydrological conditions and anthropogenic activities on the dynamics of the communities. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  14. Comparison of Natural Drainage Group and Negative Drainage Groups after Total Thyroidectomy: Prospective Randomized Controlled Study

    Science.gov (United States)

    Woo, Seung Hoon; Kim, Jin Pyeong; Park, Jung Je; Shim, Hyun Seok; Lee, Sang Ha; Lee, Ho Joong; Won, Seong Jun; Son, Hee Young; Kim, Rock Bum

    2013-01-01

    Purpose The aim of this study was to compare a negative pressure drain with a natural drain in order to determine whether a negative pressure drainage tube causes an increase in the drainage volume. Materials and Methods Sixty-two patients who underwent total thyroidectomy for papillary thyroid carcinoma (PTC) were enrolled in the study between March 2010 and August 2010 at Gyeongsang National University Hospital. The patients were prospectively and randomly assigned to two groups, a negative pressure drainage group (n=32) and natural drainage group (n=30). Every 3 hours, the volume of drainage was checked in the two groups until the tube was removed. Results The amount of drainage during the first 24 hours postoperatively was 41.68±3.93 mL in the negative drain group and 25.3±2.68 mL in the natural drain group (pdrainage at postoperative day 3 was not statistically different between the two groups. In addition, the vocal cord palsy and temporary and permanent hypocalcemia were not different between the two groups. Conclusion These results indicate that a negative pressure drain may increase the amount of drainage during the first 24-48 hours postoperatively. Therefore, it is not necessary to place a closed suction drain when only a total thyroidectomy is done. PMID:23225820

  15. Bacterioplankton assembly and interspecies interaction indicating increasing coastal eutrophication.

    Science.gov (United States)

    Dai, Wenfang; Zhang, Jinjie; Tu, Qichao; Deng, Ye; Qiu, Qiongfen; Xiong, Jinbo

    2017-06-01

    Anthropogenic perturbations impose negative effects on coastal ecosystems, such as increasing levels of eutrophication. Given the biogeochemical significance of microorganisms, understanding the processes and mechanisms underlying their spatial distribution under changing environmental conditions is critical. To address this question, we examined how coastal bacterioplankton communities respond to increasing eutrophication levels created by anthropogenic perturbations. The results showed that the magnitude of changes in the bacterioplankton community compositions (BCCs) and the importance of deterministic processes that constrained bacterial assembly were closely associated with eutrophication levels. Moreover, increasing eutrophication significantly (P bacterioplankton community is limited, with disrupted interspecies interaction occurring under heavy eutrophication. As such, bacterial assemblages are sensitive to changes in environmental conditions and could thus potentially serve as bio-indicators for increasing eutrophication. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Seasonal Dynamics of Bacterioplankton Community Structure in a Eutrophic Lake as Determined by 5S rRNA Analysis

    Science.gov (United States)

    Höfle, Manfred G.; Haas, Heike; Dominik, Katja

    1999-01-01

    Community structure of bacterioplankton was studied during the major growth season for phytoplankton (April to October) in the epilimnion of a temperate eutrophic lake (Lake Plußsee, northern Germany) by using comparative 5S rRNA analysis. Estimates of the relative abundances of single taxonomic groups were made on the basis of the amounts of single 5S rRNA bands obtained after high-resolution electrophoresis of RNA directly from the bacterioplankton. Full-sequence analysis of single environmental 5S rRNAs enabled the identification of single taxonomic groups of bacteria. Comparison of partial 5S rRNA sequences allowed the detection of changes of single taxa over time. Overall, the whole bacterioplankton community showed two to eight abundant (>4% of the total 5S rRNA) taxa. A distinctive seasonal succession was observed in the taxonomic structure of this pelagic community. A rather-stable community structure, with seven to eight different taxonomic units, was observed beginning in April during the spring phytoplankton bloom. A strong reduction in this diversity occurred at the beginning of the clear-water phase (early May), when only two to four abundant taxa were observed, with one taxon dominating (up to 72% of the total 5S rRNA). The community structure during summer stagnation (June and July) was characterized by frequent changes of different dominating taxa. During late summer, a dinoflagellate bloom (Ceratium hirudinella) occurred, with Comamonas acidovorans (β-subclass of the class Proteobacteria) becoming the dominant bacterial species (average abundance of 43% of the total 5S rRNA). Finally, the seasonal dynamics of the community structure of bacterioplankton were compared with the abundances of other major groups of the aquatic food web, such as phyto- and zooplankton, revealing that strong grazing pressure by zooplankton can reduce microbial diversity substantially in pelagic environments. PMID:10388718

  17. Mustelidae are natural hosts of Staphylococcus delphini group A

    DEFF Research Database (Denmark)

    Guardabassi, Luca; Schmidt, Kristina Runge; Petersen, Tina Steiner

    2012-01-01

    158 SIG isolates from less studied animal species belonging to the order Carnivora, including mink (n=118), fox (n=33), badger (n=6) and ferret (n=1). Species identification was performed by nuc PCR in combination with sodA sequence analysis and pta PCR restriction fragment length polymorphism (RFLP......). The results showed a consistent association between host and bacterial species. All isolates from minks, ferret and badgers belonged to S. delphini group A, whereas all fox isolates except one were identified as S. pseudintermedius. The remaining fox isolate belonged to S. delphini group A. The results...... indicate that Mustelidae such as minks, ferrets and badgers are natural hosts of S. delphini group A. This is in contrast with Canidae, which are primarily colonized and infected with S. pseudintermedius. These findings suggest that coagulase-positive staphylococcal species may have evolved and diverged...

  18. Stream hydrological fragmentation drives bacterioplankton community composition.

    Directory of Open Access Journals (Sweden)

    Stefano Fazi

    Full Text Available In Mediterranean intermittent streams, the hydrological fragmentation in summer and the successive water flow re-convergence in autumn allow exploring how local processes shape the microbial community within the same habitat. The objectives of this study were to determine how bacterial community composition responded to hydrological fragmentation in summer, and to evaluate whether the seasonal shifts in community composition predominate over the effects of episodic habitat fragmentation. The bacterial community was assessed along the intermittent stream Fuirosos (Spain, at different levels of phylogenetic resolution by in situ hybridization, fingerprinting, and 16S rRNA gene sequencing. The hydrological fragmentation of the stream network strongly altered the biogeochemical conditions with the depletion of oxidized solutes and caused changes in dissolved organic carbon characteristics. In the isolated ponds, beta-Proteobacteria and Actinobacteria increased their abundance with a gradual reduction of the alpha-diversity as pond isolation time increased. Moreover, fingerprinting analysis clearly showed a shift in community composition between summer and autumn. In the context of a seasonal shift, the temporary stream fragmentation simultaneously reduced the microbial dispersion and affected local environmental conditions (shift in redox regime and quality of the dissolved organic matter tightly shaping the bacterioplankton community composition.

  19. Vertical partitioning of freshwater bacterioplankton community in a deep mesotrophic lake with a fully oxygenated hypolimnion (Lake Biwa, Japan).

    Science.gov (United States)

    Okazaki, Yusuke; Nakano, Shin-Ichi

    2016-07-12

    In freshwater microbial ecology, extensive studies are attempting to characterize the vast majority of uncultivated bacterioplankton taxa. However, these studies mainly focus on the epilimnion and little is known regarding the bacterioplankton inhabiting the hypolimnion of deep holomictic lakes, despite its biogeochemical importance. In this study, we investigated the bacterioplankton community composition in a deep freshwater lake with a fully oxygenated hypolimnion (Lake Biwa, Japan) using high-throughput 16S rRNA gene amplicon sequencing. Sampling at a pelagic site over 15 months throughout the water column revealed that the community composition in the hypolimnion was significantly different from that in the epilimnion. The bacterial community in the hypolimnion was composed of groups dominating in the whole water layer (e.g., bacI-A1 and acI-B1) and groups that were hypolimnion habitat specialists. Among the hypolimnion specialists, members of Chloroflexi and Planctomycetes were highly represented (e.g., CL500-11, CL500-15 and CL500-37), followed by members of Acidobacteria, Chlorobi and nitrifiers (e.g., Ca. Nitrosoarchaeum, Nitrosospira and Nitrospira). This study identified the number of previously understudied taxa dominating the deep aerobic freshwater habitat, suggesting that the biogeochemical cycling there is driven by the microbial community that are different from that in the epilimnion. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Phylogenetic shifts of bacterioplankton community composition along the Pearl Estuary: the potential impact of hypoxia and nutrients.

    Science.gov (United States)

    Liu, Jiwen; Fu, Bingbing; Yang, Hongmei; Zhao, Meixun; He, Biyan; Zhang, Xiao-Hua

    2015-01-01

    The significance of salinity in shaping bacterial communities dwelling in estuarine areas has been well documented. However, the influences of other environmental factors such as dissolved oxygen and nutrients in determining distribution patterns of both individual taxa and bacterial communities inhabited local estuarine regions remain elusive. Here, bacterioplankton community structures of surface and bottom waters from eight sites along the Pearl Estuary were characterized with 16S rRNA gene pyrosequencing. The results showed significant differences of bacterioplankton community between freshwater and saltwater sites, and further between surface and bottom waters of saltwater sites. Synechococcus dominated the surface water of saltwater sites while Oceanospirillales, SAR11 and SAR406 were prevalent in the bottom water. Betaproteobacteria was abundant in freshwater sites, with no significant difference between water layers. Occurrence of phylogenetic shifts in taxa affiliated to the same clade was also detected. Dissolved oxygen explained most of the bacterial community variation in the redundancy analysis targeting only freshwater sites, whereas nutrients and salinity explained most of the variation across all samples in the Pearl Estuary. Methylophilales (mainly PE2 clade) was positively correlated to dissolved oxygen, whereas Rhodocyclales (mainly R.12up clade) was negatively correlated. Moreover, high nutrient inputs to the freshwater area of the Pearl Estuary have shifted the bacterial communities toward copiotrophic groups, such as Sphingomonadales. The present study demonstrated that the overall nutrients and freshwater hypoxia play important roles in determining bacterioplankton compositions and provided insights into the potential ecological roles of specific taxa in estuarine environments.

  1. Spatial-Temporal Changes of Bacterioplankton Community along an Exhorheic River.

    Science.gov (United States)

    Ma, Lili; Mao, Guannan; Liu, Jie; Gao, Guanghai; Zou, Changliang; Bartlam, Mark G; Wang, Yingying

    2016-01-01

    To date, few aquatic microbial ecology studies have discussed the variability of the microbial community in exorheic river ecosystems on both the spatial and seasonal scales. In this study, we examined the spatio-temporal variation of bacterioplankton community composition in an anthropogenically influenced exorheic river, the Haihe River in Tianjin, China, using pyrosequencing analysis of 16S rRNA genes. It was verified by one-way ANOVA that the spatial variability of the bacterioplankton community composition over the whole river was stronger than the seasonal variation. Salinity was a major factor leading to spatial differentiation of the microbial community structure into riverine and estuarial parts. A high temperature influence on the seasonal bacterial community variation was only apparent within certain kinds of environments (e.g., the riverine part). Bacterial community richness and diversity both exhibited significant spatial changes, and their seasonal variations were completely different in the two environments studied here. Furthermore, riverine bacterial community assemblages were subdivided into urban and rural groups due to changes in the nutritional state of the river. In addition, the nutrient-loving group including Limnohabitans, Hydrogenophaga, and Polynucleobacter were abundant in the urbanized Haihe River, indicating the environmental factors in these anthropogenic waterbodies heavily influence the core freshwater community composition.

  2. Phytoplankton, bacterioplankton and virioplankton structure and function across the southern Great Barrier Reef shelf

    Science.gov (United States)

    Alongi, Daniel M.; Patten, Nicole L.; McKinnon, David; Köstner, Nicole; Bourne, David G.; Brinkman, Richard

    2015-02-01

    Bacterioplankton and phytoplankton dynamics, pelagic respiration, virioplankton abundance, and the diversity of pelagic diazotrophs and other bacteria were examined in relation to water-column nutrients and vertical mixing across the southern Great Barrier Reef (GBR) shelf where sharp inshore to offshore gradients in water chemistry and hydrology prevail. A principal component analysis (PCA) revealed station groups clustered geographically, suggesting across-shelf differences in plankton function and structure driven by changes in mixing intensity, sediment resuspension, and the relative contributions of terrestrial, reef and oceanic nutrients. At most stations and sampling periods, microbial abundance and activities peaked both inshore and at channels between outer shelf reefs of the Pompey Reef complex. PCA also revealed that virioplankton numbers and biomass correlated with bacterioplankton numbers and production, and that bacterial growth and respiration correlated with net primary production, suggesting close virus-bacteria-phytoplankton interactions; all plankton groups correlated with particulate C, N, and P. Strong vertical mixing facilitates tight coupling of pelagic and benthic shelf processes as, on average, 37% and 56% of N and P demands of phytoplankton are derived from benthic nutrient regeneration and resuspension. These across-shelf planktonic trends mirror those of the benthic microbial community.

  3. Linking Compositional and Functional Predictions to Decipher the Biogeochemical Significance in DFAA Turnover of Abundant Bacterioplankton Lineages in the North Sea.

    Science.gov (United States)

    Wemheuer, Bernd; Wemheuer, Franziska; Meier, Dimitri; Billerbeck, Sara; Giebel, Helge-Ansgar; Simon, Meinhard; Scherber, Christoph; Daniel, Rolf

    2017-11-05

    Deciphering the ecological traits of abundant marine bacteria is a major challenge in marine microbial ecology. In the current study, we linked compositional and functional predictions to elucidate such traits for abundant bacterioplankton lineages in the North Sea. For this purpose, we investigated entire and active bacterioplankton composition along a transect ranging from the German Bight to the northern North Sea by pyrotag sequencing of bacterial 16S rRNA genes and transcripts. Functional profiles were inferred from 16S rRNA data using Tax4Fun. Bacterioplankton communities were dominated by well-known marine lineages including clusters/genera that are affiliated with the Roseobacter group and the Flavobacteria . Variations in community composition and function were significantly explained by measured environmental and microbial properties. Turnover of dissolved free amino acids (DFAA) showed the strongest correlation to community composition and function. We applied multinomial models, which enabled us to identify bacterial lineages involved in DFAA turnover. For instance, the genus Planktomarina was more abundant at higher DFAA turnover rates, suggesting its vital role in amino acid degradation. Functional predictions further indicated that Planktomarina is involved in leucine and isoleucine degradation. Overall, our results provide novel insights into the biogeochemical significance of abundant bacterioplankton lineages in the North Sea.

  4. Linking Compositional and Functional Predictions to Decipher the Biogeochemical Significance in DFAA Turnover of Abundant Bacterioplankton Lineages in the North Sea

    Directory of Open Access Journals (Sweden)

    Bernd Wemheuer

    2017-11-01

    Full Text Available Deciphering the ecological traits of abundant marine bacteria is a major challenge in marine microbial ecology. In the current study, we linked compositional and functional predictions to elucidate such traits for abundant bacterioplankton lineages in the North Sea. For this purpose, we investigated entire and active bacterioplankton composition along a transect ranging from the German Bight to the northern North Sea by pyrotag sequencing of bacterial 16S rRNA genes and transcripts. Functional profiles were inferred from 16S rRNA data using Tax4Fun. Bacterioplankton communities were dominated by well-known marine lineages including clusters/genera that are affiliated with the Roseobacter group and the Flavobacteria. Variations in community composition and function were significantly explained by measured environmental and microbial properties. Turnover of dissolved free amino acids (DFAA showed the strongest correlation to community composition and function. We applied multinomial models, which enabled us to identify bacterial lineages involved in DFAA turnover. For instance, the genus Planktomarina was more abundant at higher DFAA turnover rates, suggesting its vital role in amino acid degradation. Functional predictions further indicated that Planktomarina is involved in leucine and isoleucine degradation. Overall, our results provide novel insights into the biogeochemical significance of abundant bacterioplankton lineages in the North Sea.

  5. Systems Biology and Ecology of Streamlined Bacterioplankton

    Science.gov (United States)

    Giovannoni, S. J.

    2014-12-01

    The salient feature of streamlined cells is their small genome size, but "streamlining" refers more generally to selection that favors minimization of cell size and complexity. The essence of streamlining theory is that selection is most efficient in organisms that have large effective population sizes, and, in nutrient-limited systems, favors cell architecture that minimizes resources required for replication. Regardless of the cause of genome reduction, lost coding potential eventually dictates loss of function, raising the questions, what genome features are expendable, and how do cells become highly successful with a minimal genomic repertoire? One consequence of reductive evolution in streamlined organisms is atypical patterns of prototrophy, for example the recent discovery of a requirement for the thiamin precursor 4-amino-5-hydroxymethyl-2-methylpyrimidine in some plankton taxa. Examples such as this fit within the framework of the Black Queen Hypothesis, which describes genome reduction that results in reliance on community goods and increased community connectivity. Other examples of genome reduction include losses of regulatory functions, or replacement with simpler regulatory systems, and increased metabolic integration. In one such case, in the order Pelagibacterales, the PII system for regulating responses to N limitation has been replaced with a simpler system composed of fewer genes. Both the absence of common regulatory systems and atypical patterns of prototrophy have been linked to difficulty in culturing Pelagibacterales, lending credibility to the idea that streamlining might broadly explain the phenomenon of the uncultured microbial majority. The success of streamlined osmotrophic bacterioplankton suggests that they successfully compete for labile organic matter and capture a large share of this resource, but an alternative theory postulates they are not good resource competitors and instead prosper by avoiding predation. The answers to these

  6. Temporal variation in the specific growth rate of bacterioplankton in the River Cauvery and its four down stream tributaries in Karnataka State, India.

    Science.gov (United States)

    Tondoti Sathyanarayana Rao, Harsha; Yamakanamardi, Sadanand Mallappa; Mallaiah, Mahadeveswamy

    2009-07-01

    The temporal variation in the Specific Growth Rate (SGR) of natural population of heterotrophic bacterioplankton of the river Cauvery and its four down stream tributaries in Karnataka State was monitored over a period of two years from February 2000 to January 2002. The SGR was calculated by taking into account only the abundance of bacterioplankton at the beginning (0 h) and at the end (48 h) incubation period, at room or river temperature. The mean SGR was less and significantly different in the surface waters of river Kapila, Shimsha, Suvarnavathy and Arkavathy. But it was more and significantly different in river Cauvery when compared to other tributaries. This suggests that the river Cauvery was more favorable habitat for SGR of bacterioplankton than the other four watercourses studied. Investigation of interrelationship between SGR and other bacterial variables showed presence of only one correlation with direct counts of particle bound bacteria in river Arkavathy. Further, the relationship between SGR of bacterioplankton and other environmental variables showed the presence of six correlations in river Shimsha, five in river Suvarnavathy, three in river Cauvery, and two each in river Kapila and river Arkavathy. Negative SGR were recorded on thirteen occasions in river Cauvery followed by eleven in river Shimsha, nine in river Suvarnavathy, seven in river Arkavathy and five in river Kapila, out of fifty SGR determinations. This negative SGR were a result of decrease in the observed bacterial cell counts after 48 h incubation from that of 0 h count. The probable reason for such negative growth rate and dependency of SGR of bacterioplankton and environmental variables has been discussed.

  7. Relationship between Bacterioplankton Richness, Respiration, and Production in the Southern North Sea

    OpenAIRE

    Reinthaler, Thomas; Winter, Christian; Herndl, Gerhard J.

    2005-01-01

    We investigated the relationship between bacterioplankton production (BP), respiration (BR), and community composition measured by terminal restriction fragment length polymorphism in the southern North Sea over a seasonal cycle. Major changes in bacterioplankton richness were apparent from April to December. While cell-specific BP decreased highly significantly with increasing bacterioplankton richness, cell-specific BR was found to be variable along the richness gradient, suggesting that ba...

  8. Short-term dynamics of North Sea bacterioplankton-dissolved organic matter coherence on molecular level

    Directory of Open Access Journals (Sweden)

    Judith eLucas

    2016-03-01

    Full Text Available Remineralisation and transformation of dissolved organic matter (DOM by marine microbes shape the DOM composition and thus, have large impact on global carbon and nutrient cycling. However, information on bacterioplankton-DOM interactions on a molecular level is limited. We examined the variation of bacterial community composition at Helgoland Roads (North Sea in relation to variation of molecular DOM composition and various environmental parameters on short-time scales. Surface water samples were taken daily over a period of twenty days. Bacterial community and molecular DOM composition were assessed via 16S rRNA gene tag sequencing and ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS, respectively. Environmental conditions were driven by a coastal water influx during the first half of the sampling period and the onset of a summer phytoplankton bloom towards the end of the sampling period. These phenomena led to a distinct grouping of bacterial communities and DOM composition which was particularly influenced by total dissolved nitrogen concentration, temperature and salinity, as revealed by distance-based linear regression analyses. Bacterioplankton-DOM interaction was demonstrated in strong correlations between specific bacterial taxa and particular DOM molecules, thus, suggesting potential specialization on particular substrates. We propose that a combination of high resolution techniques, as used in this study, may provide substantial information on substrate generalists and specialists and thus, contribute to prediction of bacterial community composition variation.

  9. Exploring the Ecological Coherence between the Spatial and Temporal Patterns of Bacterioplankton in Boreal Lakes

    Directory of Open Access Journals (Sweden)

    Juan Pablo Niño-García

    2017-04-01

    Full Text Available One of the major contemporary challenges in microbial ecology has been to discriminate the reactive core from the random, unreactive components of bacterial communities. In previous work we used the spatial abundance distributions of bacterioplankton across boreal lakes of Québec to group taxa into four distinct categories that reflect either hydrology-mediated dispersal along the aquatic network or environmental selection mechanisms within lakes. Here, we test whether this categorization derived from the spatial distribution of taxa is maintained over time, by analyzing the temporal dynamics of the operational taxonomic units (OTUs within those spatially derived categories along an annual cycle in the oligotrophic lake Croche (Québec, Canada, and assessing the coherence in the patterns of abundance, occurrence, and environmental range of these OTUs over space and time. We report that the temporal dynamics of most taxa within a single lake are largely coherent with those derived from their spatial distribution over large spatial scales, suggesting that these properties must be intrinsic of particular taxa. We also identified a set of rare taxa cataloged as having a random occupancy based on their spatial distribution, but which showed clear seasonality and abundance peaks along the year, yet these comprised a very small fraction of the total rare OTUs. We conclude that the presence of most rare bacterioplankton taxa in boreal lakes is random, since both their temporal and spatial dynamics suggest links to passive downstream transport and persistence in freshwater networks, rather than environmental selection.

  10. Short-Term Dynamics of North Sea Bacterioplankton-Dissolved Organic Matter Coherence on Molecular Level.

    Science.gov (United States)

    Lucas, Judith; Koester, Irina; Wichels, Antje; Niggemann, Jutta; Dittmar, Thorsten; Callies, Ulrich; Wiltshire, Karen H; Gerdts, Gunnar

    2016-01-01

    Remineralization and transformation of dissolved organic matter (DOM) by marine microbes shape the DOM composition and thus, have large impact on global carbon and nutrient cycling. However, information on bacterioplankton-DOM interactions on a molecular level is limited. We examined the variation of bacterial community composition (BCC) at Helgoland Roads (North Sea) in relation to variation of molecular DOM composition and various environmental parameters on short-time scales. Surface water samples were taken daily over a period of 20 days. Bacterial community and molecular DOM composition were assessed via 16S rRNA gene tag sequencing and ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), respectively. Environmental conditions were driven by a coastal water influx during the first half of the sampling period and the onset of a summer phytoplankton bloom toward the end of the sampling period. These phenomena led to a distinct grouping of bacterial communities and DOM composition which was particularly influenced by total dissolved nitrogen (TDN) concentration, temperature, and salinity, as revealed by distance-based linear regression analyses. Bacterioplankton-DOM interaction was demonstrated in strong correlations between specific bacterial taxa and particular DOM molecules, thus, suggesting potential specialization on particular substrates. We propose that a combination of high resolution techniques, as used in this study, may provide substantial information on substrate generalists and specialists and thus, contribute to prediction of BCC variation.

  11. Exploring the Ecological Coherence between the Spatial and Temporal Patterns of Bacterioplankton in Boreal Lakes.

    Science.gov (United States)

    Niño-García, Juan Pablo; Ruiz-González, Clara; Del Giorgio, Paul A

    2017-01-01

    One of the major contemporary challenges in microbial ecology has been to discriminate the reactive core from the random, unreactive components of bacterial communities. In previous work we used the spatial abundance distributions of bacterioplankton across boreal lakes of Québec to group taxa into four distinct categories that reflect either hydrology-mediated dispersal along the aquatic network or environmental selection mechanisms within lakes. Here, we test whether this categorization derived from the spatial distribution of taxa is maintained over time, by analyzing the temporal dynamics of the operational taxonomic units (OTUs) within those spatially derived categories along an annual cycle in the oligotrophic lake Croche (Québec, Canada), and assessing the coherence in the patterns of abundance, occurrence, and environmental range of these OTUs over space and time. We report that the temporal dynamics of most taxa within a single lake are largely coherent with those derived from their spatial distribution over large spatial scales, suggesting that these properties must be intrinsic of particular taxa. We also identified a set of rare taxa cataloged as having a random occupancy based on their spatial distribution, but which showed clear seasonality and abundance peaks along the year, yet these comprised a very small fraction of the total rare OTUs. We conclude that the presence of most rare bacterioplankton taxa in boreal lakes is random, since both their temporal and spatial dynamics suggest links to passive downstream transport and persistence in freshwater networks, rather than environmental selection.

  12. Response of marine bacterioplankton pH homeostasis gene expression to elevated CO2

    Science.gov (United States)

    Bunse, Carina; Lundin, Daniel; Karlsson, Christofer M. G.; Akram, Neelam; Vila-Costa, Maria; Palovaara, Joakim; Svensson, Lovisa; Holmfeldt, Karin; González, José M.; Calvo, Eva; Pelejero, Carles; Marrasé, Cèlia; Dopson, Mark; Gasol, Josep M.; Pinhassi, Jarone

    2016-05-01

    Human-induced ocean acidification impacts marine life. Marine bacteria are major drivers of biogeochemical nutrient cycles and energy fluxes; hence, understanding their performance under projected climate change scenarios is crucial for assessing ecosystem functioning. Whereas genetic and physiological responses of phytoplankton to ocean acidification are being disentangled, corresponding functional responses of bacterioplankton to pH reduction from elevated CO2 are essentially unknown. Here we show, from metatranscriptome analyses of a phytoplankton bloom mesocosm experiment, that marine bacteria responded to lowered pH by enhancing the expression of genes encoding proton pumps, such as respiration complexes, proteorhodopsin and membrane transporters. Moreover, taxonomic transcript analysis showed that distinct bacterial groups expressed different pH homeostasis genes in response to elevated CO2. These responses were substantial for numerous pH homeostasis genes under low-chlorophyll conditions (chlorophyll a 20 μg l-1) were low. Given that proton expulsion through pH homeostasis mechanisms is energetically costly, these findings suggest that bacterioplankton adaptation to ocean acidification could have long-term effects on the economy of ocean ecosystems.

  13. Testing the Metabolic Theory of Ecology with marine bacteria: Different temperature sensitivity of major phylogenetic groups during the spring phytoplankton bloom

    KAUST Repository

    Arandia-Gorostidi, Nestor

    2017-08-24

    Although temperature is a key driver of bacterioplankton metabolism, the effect of ocean warming on different bacterial phylogenetic groups remains unclear. Here, we conducted monthly short-term incubations with natural coastal bacterial communities over an annual cycle to test the effect of experimental temperature on the growth rates and carrying capacities of four phylogenetic groups: SAR11, Rhodobacteraceae, Gammaproteobacteria and Bacteroidetes. SAR11 was the most abundant group year-round as analysed by CARD-FISH, with maximum abundances in summer, while the other taxa peaked in spring. All groups, including SAR11, showed high temperature-sensitivity of growth rates and/or carrying capacities in spring, under phytoplankton bloom or post-bloom conditions. In that season, Rhodobacteraceae showed the strongest temperature response in growth rates, estimated here as activation energy (E, 1.43 eV), suggesting an advantage to outcompete other groups under warmer conditions. In summer E values were in general lower than 0.65 eV, the value predicted by the Metabolic Theory of Ecology (MTE). Contrary to MTE predictions, carrying capacity tended to increase with warming for all bacterial groups. Our analysis confirms that resource availability is key when addressing the temperature response of heterotrophic bacterioplankton. We further show that even under nutrient-sufficient conditions, warming differentially affected distinct bacterioplankton taxa. This article is protected by copyright. All rights reserved.

  14. Metabolic Roles of Uncultivated Bacterioplankton Lineages in the Northern Gulf of Mexico "Dead Zone".

    Science.gov (United States)

    Thrash, J Cameron; Seitz, Kiley W; Baker, Brett J; Temperton, Ben; Gillies, Lauren E; Rabalais, Nancy N; Henrissat, Bernard; Mason, Olivia U

    2017-09-12

    Marine regions that have seasonal to long-term low dissolved oxygen (DO) concentrations, sometimes called "dead zones," are increasing in number and severity around the globe with deleterious effects on ecology and economics. One of the largest of these coastal dead zones occurs on the continental shelf of the northern Gulf of Mexico (nGOM), which results from eutrophication-enhanced bacterioplankton respiration and strong seasonal stratification. Previous research in this dead zone revealed the presence of multiple cosmopolitan bacterioplankton lineages that have eluded cultivation, and thus their metabolic roles in this ecosystem remain unknown. We used a coupled shotgun metagenomic and metatranscriptomic approach to determine the metabolic potential of Marine Group II Euryarchaeota , SAR406, and SAR202. We recovered multiple high-quality, nearly complete genomes from all three groups as well as candidate phyla usually associated with anoxic environments- Parcubacteria (OD1) and Peregrinibacteria Two additional groups with putative assignments to ACD39 and PAUC34f supplement the metabolic contributions by uncultivated taxa. Our results indicate active metabolism in all groups, including prevalent aerobic respiration, with concurrent expression of genes for nitrate reduction in SAR406 and SAR202, and dissimilatory nitrite reduction to ammonia and sulfur reduction by SAR406. We also report a variety of active heterotrophic carbon processing mechanisms, including degradation of complex carbohydrate compounds by SAR406, SAR202, ACD39, and PAUC34f. Together, these data help constrain the metabolic contributions from uncultivated groups in the nGOM during periods of low DO and suggest roles for these organisms in the breakdown of complex organic matter. IMPORTANCE Dead zones receive their name primarily from the reduction of eukaryotic macrobiota (demersal fish, shrimp, etc.) that are also key coastal fisheries. Excess nutrients contributed from anthropogenic activity

  15. Temporal patterns of phyto- and bacterioplankton and their relationships with environmental factors in Lake Taihu, China.

    Science.gov (United States)

    Su, Xiaomei; Steinman, Alan D; Xue, Qingju; Zhao, Yanyan; Tang, Xiangming; Xie, Liqiang

    2017-10-01

    Phytoplankton and bacterioplankton are integral components of aquatic food webs and play essential roles in the structure and function of freshwater ecosystems. However, little is known about how phyto- and bacterioplankton may respond synchronously to changing environmental conditions. Thus, we analyzed simultaneously the composition and structure of phyto- and bacterioplankton on a monthly basis over 12 months in cyanobacteria-dominated areas of Lake Taihu and compared their responses to changes in environmental factors. Metric multi-dimensional scaling (mMDS) revealed that the temporal variations of phyto- and bacterioplankton were significant. Time lag analysis (TLA) indicated that the temporal pattern of phytoplankton tended to exhibit convergent dynamics while bacterioplankton showed highly stable or stochastic variation. A significant directional change was found for bacterioplankton at the genus level and the slopes (rate of change) and regression R 2 (low stochasticity or stability) were greater if Cyanobacteria were included, suggesting a higher level of instability in the bacterial community at lower taxonomy level. Consequently, phytoplankton responded more rapidly to the change in environmental conditions than bacterioplankton when analyzed at the phylum level, while bacterioplankton were more sensitive at the finer taxonomic resolution in Lake Taihu. Redundancy analysis (RDA) results showed that environmental variables collectively explained 51.0% variance of phytoplankton and 46.7% variance of bacterioplankton, suggesting that environmental conditions have a significant influence on the temporal variations of phyto- and bacterioplankton. Furthermore, variance partitioning indicated that the bacterial community structure was largely explained by water temperature and nitrogen, suggesting that these factors were the primary drivers shaping bacterioplankton. Copyright © 2017. Published by Elsevier Ltd.

  16. Quantification of carbon and phosphorus co-limitation in bacterioplankton: new insights on an old topic.

    Directory of Open Access Journals (Sweden)

    Irene Dorado-García

    Full Text Available Because the nature of the main resource that limits bacterioplankton (e.g. organic carbon [C] or phosphorus [P] has biogeochemical implications concerning organic C accumulation in freshwater ecosystems, empirical knowledge is needed concerning how bacteria respond to these two resources, available alone or together. We performed field experiments of resource manipulation (2×2 factorial design, with the addition of C, P, or both combined in two Mediterranean freshwater ecosystems with contrasting trophic states (oligotrophy vs. eutrophy and trophic natures (autotrophy vs. heterotrophy, measured as gross primary production:respiration ratio. Overall, the two resources synergistically co-limited bacterioplankton, i.e. the magnitude of the response of bacterial production and abundance to the two resources combined was higher than the additive response in both ecosystems. However, bacteria also responded positively to single P and C additions in the eutrophic ecosystem, but not to single C in the oligotrophic one, consistent with the value of the ratio between bacterial C demand and algal C supply. Accordingly, the trophic nature rather than the trophic state of the ecosystems proves to be a key feature determining the expected types of resource co-limitation of bacteria, as summarized in a proposed theoretical framework. The actual types of co-limitation shifted over time and partially deviated (a lesser degree of synergism from the theoretical expectations, particularly in the eutrophic ecosystem. These deviations may be explained by extrinsic ecological forces to physiological limitations of bacteria, such as predation, whose role in our experiments is supported by the relationship between the dynamics of bacteria and bacterivores tested by SEMs (structural equation models. Our study, in line with the increasingly recognized role of freshwater ecosystems in the global C cycle, suggests that further attention should be focussed on the biotic

  17. Quantification of Carbon and Phosphorus Co-Limitation in Bacterioplankton: New Insights on an Old Topic

    Science.gov (United States)

    Dorado-García, Irene; Medina-Sánchez, Juan Manuel; Herrera, Guillermo; Cabrerizo, Marco J.; Carrillo, Presentación

    2014-01-01

    Because the nature of the main resource that limits bacterioplankton (e.g. organic carbon [C] or phosphorus [P]) has biogeochemical implications concerning organic C accumulation in freshwater ecosystems, empirical knowledge is needed concerning how bacteria respond to these two resources, available alone or together. We performed field experiments of resource manipulation (2×2 factorial design, with the addition of C, P, or both combined) in two Mediterranean freshwater ecosystems with contrasting trophic states (oligotrophy vs. eutrophy) and trophic natures (autotrophy vs. heterotrophy, measured as gross primary production:respiration ratio). Overall, the two resources synergistically co-limited bacterioplankton, i.e. the magnitude of the response of bacterial production and abundance to the two resources combined was higher than the additive response in both ecosystems. However, bacteria also responded positively to single P and C additions in the eutrophic ecosystem, but not to single C in the oligotrophic one, consistent with the value of the ratio between bacterial C demand and algal C supply. Accordingly, the trophic nature rather than the trophic state of the ecosystems proves to be a key feature determining the expected types of resource co-limitation of bacteria, as summarized in a proposed theoretical framework. The actual types of co-limitation shifted over time and partially deviated (a lesser degree of synergism) from the theoretical expectations, particularly in the eutrophic ecosystem. These deviations may be explained by extrinsic ecological forces to physiological limitations of bacteria, such as predation, whose role in our experiments is supported by the relationship between the dynamics of bacteria and bacterivores tested by SEMs (structural equation models). Our study, in line with the increasingly recognized role of freshwater ecosystems in the global C cycle, suggests that further attention should be focussed on the biotic interactions that

  18. Temporal dynamics of bacterioplankton communities in response to excessive nitrate loading in oligotrophic coastal water.

    Science.gov (United States)

    Dong, Zhiying; Wang, Kai; Chen, Xinxin; Zhu, Jianlin; Hu, Changju; Zhang, Demin

    2017-01-30

    Coastal ecosystems are receiving elevated loads of nitrogen (N) from anthropogenic sources. Understanding how excessive N loading affects bacterioplankton communities is critical to predict the biodiversity of marine ecosystems under conditions of eutrophic disturbance. In this study, oligotrophic coastal water microcosms were perturbed with nitrate in two loading modes: 1) one-off loading at the beginning of the incubation period; and 2) periodic loading every two days for 16days. Turnover in the bacterioplankton community was investigated by 16S rDNA gene amplicon sequencing. The alpha diversity of the bacterioplankton community showed great temporal variability and similar responses to the different treatments. Bacterioplankton community composition was influenced remarkably by time and N loading mode. The effects of N loading on bacterioplankton community structure showed obvious temporal variation, probably because of the great temporal variation in environmental parameters. This study provides insights into the effects of N pollution in anthropogenically perturbed marine environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. On the Nature of Compact Groups of Galaxies

    Science.gov (United States)

    de Carvalho, Reinaldo R.

    Based on the spectroscopic survey of de Carvalho et al. (1997), we analyse the structural and dynamical properties of 17 Hickson Compact Groups (HCG). This analysis probes a region of 0.5o times 0.5o around each group and shows that most are part of larger structures. Our results also suggest that the Hickson sample is composed of different dynamical stages of the group's evolution. Specifically, we identify three possible evolutionary phases among groups in the sample: loose groups, [core+halo] systems and compact groups, each one presenting a distinct surface density profile. This sequence is consistent with the replenishment scenario for the formation and evolution of compact groups within larger and less dense systems.

  20. Transient changes in bacterioplankton communities induced by the submarine volcanic eruption of El Hierro (Canary Islands.

    Directory of Open Access Journals (Sweden)

    Isabel Ferrera

    Full Text Available The submarine volcanic eruption occurring near El Hierro (Canary Islands in October 2011 provided a unique opportunity to determine the effects of such events on the microbial populations of the surrounding waters. The birth of a new underwater volcano produced a large plume of vent material detectable from space that led to abrupt changes in the physical-chemical properties of the water column. We combined flow cytometry and 454-pyrosequencing of 16S rRNA gene amplicons (V1-V3 regions for Bacteria and V3-V5 for Archaea to monitor the area around the volcano through the eruptive and post-eruptive phases (November 2011 to April 2012. Flow cytometric analyses revealed higher abundance and relative activity (expressed as a percentage of high-nucleic acid content cells of heterotrophic prokaryotes during the eruptive process as compared to post-eruptive stages. Changes observed in populations detectable by flow cytometry were more evident at depths closer to the volcano (~70-200 m, coinciding also with oxygen depletion. Alpha-diversity analyses revealed that species richness (Chao1 index decreased during the eruptive phase; however, no dramatic changes in community composition were observed. The most abundant taxa during the eruptive phase were similar to those in the post-eruptive stages and to those typically prevalent in oceanic bacterioplankton communities (i.e. the alphaproteobacterial SAR11 group, the Flavobacteriia class of the Bacteroidetes and certain groups of Gammaproteobacteria. Yet, although at low abundance, we also detected the presence of taxa not typically found in bacterioplankton communities such as the Epsilonproteobacteria and members of the candidate division ZB3, particularly during the eruptive stage. These groups are often associated with deep-sea hydrothermal vents or sulfur-rich springs. Both cytometric and sequence analyses showed that once the eruption ceased, evidences of the volcano-induced changes were no longer

  1. The green impact: bacterioplankton response toward a phytoplankton spring bloom in the southern North Sea assessed by comparative metagenomic and metatranscriptomic approaches.

    Science.gov (United States)

    Wemheuer, Bernd; Wemheuer, Franziska; Hollensteiner, Jacqueline; Meyer, Frauke-Dorothee; Voget, Sonja; Daniel, Rolf

    2015-01-01

    Phytoplankton blooms exhibit a severe impact on bacterioplankton communities as they change nutrient availabilities and other environmental factors. In the current study, the response of a bacterioplankton community to a Phaeocystis globosa spring bloom was investigated in the southern North Sea. For this purpose, water samples were taken inside and reference samples outside of an algal spring bloom. Structural changes of the bacterioplankton community were assessed by amplicon-based analysis of 16S rRNA genes and transcripts generated from environmental DNA and RNA, respectively. Several marine groups responded to bloom presence. The abundance of the Roseobacter RCA cluster and the SAR92 clade significantly increased in bloom presence in the total and active fraction of the bacterial community. Functional changes were investigated by direct sequencing of environmental DNA and mRNA. The corresponding datasets comprised more than 500 million sequences across all samples. Metatranscriptomic data sets were mapped on representative genomes of abundant marine groups present in the samples and on assembled metagenomic and metatranscriptomic datasets. Differences in gene expression profiles between non-bloom and bloom samples were recorded. The genome-wide gene expression level of Planktomarina temperata, an abundant member of the Roseobacter RCA cluster, was higher inside the bloom. Genes that were differently expressed included transposases, which showed increased expression levels inside the bloom. This might contribute to the adaptation of this organism toward environmental stresses through genome reorganization. In addition, several genes affiliated to the SAR92 clade were significantly upregulated inside the bloom including genes encoding for proteins involved in isoleucine and leucine incorporation. Obtained results provide novel insights into compositional and functional variations of marine bacterioplankton communities as response to a phytoplankton bloom.

  2. Bacterioplankton carbon cycling along the Subtropical Frontal Zone off New Zealand

    Science.gov (United States)

    Baltar, Federico; Stuck, Esther; Morales, Sergio; Currie, Kim

    2015-06-01

    Marine heterotrophic bacterioplankton (Bacteria and Archaea) play a central role in ocean carbon cycling. As such, identifying the factors controlling these microbial populations is crucial to fully understanding carbon fluxes. We studied bacterioplankton activities along a transect crossing three water masses (i.e., Subtropical waters [STW], Sub-Antarctic waters [SAW] and neritic waters [NW]) with contrasting nutrient regimes across the Subtropical Frontal Zone. In contrast to bacterioplankton production and community respiration, bacterioplankton respiration increased in the offshore SAW, causing a seaward increase in the contribution of bacteria to community respiration (from 7% to 100%). Cell-specific bacterioplankton respiration also increased in SAW, but cell-specific production did not, suggesting that prokaryotic cells in SAW were investing more energy towards respiration than growth. This was reflected in a 5-fold decline in bacterioplankton growth efficiency (BGE) towards SAW. One way to explain this decrease in BGE could be due to the observed reduction in phytoplankton biomass (and presumably organic matter concentration) towards SAW. However, this would not explain why bacterioplankton respiration was highest in SAW, where phytoplankton biomass was lowest. Another factor affecting BGE could be the iron limitation characteristic of high-nutrient low-chlorophyll (HNLC) regions like SAW. Our field-study based evidences would agree with previous laboratory experiments in which iron stress provoked a decrease in BGE of marine bacterial isolates. Our results suggest that there is a strong gradient in bacterioplankton carbon cycling rates along the Subtropical Frontal Zone, mainly due to the HNLC conditions of SAW. We suggest that Fe-induced reduction of BGE in HNLC regions like SAW could be relevant in marine carbon cycling, inducing bacterioplankton to act as a link or a sink of organic carbon by impacting on the quantity of organic carbon they incorporate

  3. Bacterioplankton communities of Crater Lake, OR: Dynamic changes with euphotic zone food web structure and stable deep water populations

    Science.gov (United States)

    Urbach, E.; Vergin, K.L.; Larson, G.L.; Giovannoni, S.J.

    2007-01-01

    The distribution of bacterial and archaeal species in Crater Lake plankton varies dramatically over depth and with time, as assessed by hybridization of group-specific oligonucleotides to RNA extracted from lakewater. Nonmetric, multidimensional scaling (MDS) analysis of relative bacterial phylotype densities revealed complex relationships among assemblages sampled from depth profiles in July, August and September of 1997 through 1999. CL500-11 green nonsulfur bacteria (Phylum Chloroflexi) and marine Group I crenarchaeota are consistently dominant groups in the oxygenated deep waters at 300 and 500 m. Other phylotypes found in the deep waters are similar to surface and mid-depth populations and vary with time. Euphotic zone assemblages are dominated either by ??-proteobacteria or CL120-10 verrucomicrobia, and ACK4 actinomycetes. MDS analyses of euphotic zone populations in relation to environmental variables and phytoplankton and zooplankton population structures reveal apparent links between Daphnia pulicaria zooplankton population densities and microbial community structure. These patterns may reflect food web interactions that link kokanee salmon population densities to community structure of the bacterioplankton, via fish predation on Daphnia with cascading consequences to Daphnia bacterivory and predation on bacterivorous protists. These results demonstrate a stable bottom-water microbial community. They also extend previous observations of food web-driven changes in euphotic zone bacterioplankton community structure to an oligotrophic setting. ?? 2007 Springer Science+Business Media B.V.

  4. Building Social Capital in Groups: Facilitating Skill Development for Natural Resource Management

    Science.gov (United States)

    Kilpatrick, Sue

    2007-01-01

    Analysis of the experiences of four farmer groups set up to learn how to jointly manage local natural resource issues shows that the groups are going though two simultaneous processes. One builds technical competency in natural resource management and the other is the underpinning social process that allows the groups to make decisions and work…

  5. Flow cytometric monitoring of bacterioplankton phenotypic diversity predicts high population-specific feeding rates by invasive dreissenid mussels.

    Science.gov (United States)

    Props, Ruben; Schmidt, Marian L; Heyse, Jasmine; Vanderploeg, Henry A; Boon, Nico; Denef, Vincent J

    2018-02-01

    Species invasion is an important disturbance to ecosystems worldwide, yet knowledge about the impacts of invasive species on bacterial communities remains sparse. Using a novel approach, we simultaneously detected phenotypic and derived taxonomic change in a natural bacterioplankton community when subjected to feeding pressure by quagga mussels, a widespread aquatic invasive species. We detected a significant decrease in diversity within 1 h of feeding and a total diversity loss of 11.6 ± 4.1% after 3 h. This loss of microbial diversity was caused by the selective removal of high nucleic acid populations (29 ± 5% after 3 h). We were able to track the community diversity at high temporal resolution by calculating phenotypic diversity estimates from flow cytometry (FCM) data of minute amounts of sample. Through parallel FCM and 16S rRNA gene amplicon sequencing analysis of environments spanning a broad diversity range, we showed that the two approaches resulted in highly correlated diversity measures and captured the same seasonal and lake-specific patterns in community composition. Based on our results, we predict that selective feeding by invasive dreissenid mussels directly impacts the microbial component of the carbon cycle, as it may drive bacterioplankton communities toward less diverse and potentially less productive states. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Structuring of bacterioplankton diversity in a large tropical bay.

    Directory of Open Access Journals (Sweden)

    Gustavo B Gregoracci

    Full Text Available Structuring of bacterioplanktonic populations and factors that determine the structuring of specific niche partitions have been demonstrated only for a limited number of colder water environments. In order to better understand the physical chemical and biological parameters that may influence bacterioplankton diversity and abundance, we examined their productivity, abundance and diversity in the second largest Brazilian tropical bay (Guanabara Bay, GB, as well as seawater physical chemical and biological parameters of GB. The inner bay location with higher nutrient input favored higher microbial (including vibrio growth. Metagenomic analysis revealed a predominance of Gammaproteobacteria in this location, while GB locations with lower nutrient concentration favored Alphaproteobacteria and Flavobacteria. According to the subsystems (SEED functional analysis, GB has a distinctive metabolic signature, comprising a higher number of sequences in the metabolism of phosphorus and aromatic compounds and a lower number of sequences in the photosynthesis subsystem. The apparent phosphorus limitation appears to influence the GB metagenomic signature of the three locations. Phosphorus is also one of the main factors determining changes in the abundance of planktonic vibrios, suggesting that nutrient limitation can be observed at community (metagenomic and population levels (total prokaryote and vibrio counts.

  7. Species-Specific Associations Between Bacterioplankton and Photosynthetic Picoeukaryotes

    Science.gov (United States)

    Farnelid, H.; Turk-Kubo, K.; Zehr, J. P.

    2016-02-01

    Photosynthetic picoeukaryotes are significant contributors to marine primary productivity. Interactions between marine bacterioplankton and picoeukaryotes frequently occur and can have large biogeochemical impacts. Currently, partly due to methodological difficulties for studying microbial associations in situ, these ecological interactions are poorly characterized. Here we use flow cytometry sorting to identify novel bacterial phylotypes found in physical association with photosynthetic picoeukaryotes. Samples were collected on eight occasions at the Santa Cruz wharf on Monterey Bay during summer and fall, 2014. The phylogeny of associated microbes was assessed through clone libraries and Illumina MiSeq sequencing of amplicons of the 16S rRNA gene. In addition, 16 bacterial isolates comprised of 14 taxa were obtained from sorted photosynthetic picoeukaryote cells. The most frequently detected bacterioplankton phyla were Alphaproteobacteria, Bacteriodetes, and Gammaproteobacteria. The sequences from the sorted populations were a community distinct from the unsorted seawater samples suggesting species-specific functional associations. These species-specific patterns were further supported by re-occurring patterns between replicates and sampling dates. The finding of sequences from the free-living genera Synechococcus and Pelagibacter also suggest that photosynthetic picoeukaryotes can be bacterivores, possibly feeding on some of the most numerically abundant bacteria. The results show that specific bacterial phylotypes are found in association with photosynthetic picoeukaryotes. Taxonomic identification of these associations is a prerequisite for further characterizing the interactions, their metabolic pathways and ecological functions.

  8. In situ interactions between photosynthetic picoeukaryotes and bacterioplankton in the Atlantic Ocean: evidence for mixotrophy.

    Science.gov (United States)

    Hartmann, Manuela; Zubkov, Mikhail V; Scanlan, Dave J; Lepère, Cécile

    2013-12-01

    Heterotrophic bacterioplankton, cyanobacteria and phototrophic picoeukaryotes (bacterioplankton is often attributed to aplastidic protists, recent evidence suggests that phototrophic picoeukaryotes could be important bacterivores. Here, we present direct visual evidence from the surface mixed layer of the Atlantic Ocean that bacterioplankton are internalized by phototrophic picoeukaryotes. In situ interactions of phototrophic picoeukaryotes and bacterioplankton (specifically Prochlorococcus cyanobacteria and the SAR11 clade) were investigated using a combination of flow cytometric cell sorting and dual tyramide signal amplification fluorescence in situ hybridization. Using this method, we observed plastidic Prymnesiophyceae and Chrysophyceae cells containing Prochlorococcus, and to a lesser extent SAR11 cells. These microscopic observations of in situ microbial trophic interactions demonstrate the frequency and likely selectivity of phototrophic picoeukaryote bacterivory in the surface mixed layer of both the North and South Atlantic subtropical gyres and adjacent equatorial region, broadening our views on the ecological role of the smallest oceanic plastidic protists. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

  9. BACTERIOPLANKTON DYNAMICS IN NORTHERN SAN FRANCISCO BAY: ROLE OF PARTICLE ASSOCIATION AND SEASONAL FRESHWATER FLOW

    Science.gov (United States)

    Bacterioplankton abundance and metabolic characteristics were observed in northern San Francisco Bay, California, during spring and summer 1996 at three sites: Central Bay, Suisun Bay, and the Sacramento River. These sites spanned a salinity gradient from marine to freshwater, an...

  10. Tidal switch on metabolic activity: Salinity induced responses on bacterioplankton metabolic capabilities in a tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Thottathil, S.D.; Balachandran, K.K.; Jayalakshmy, K.V.; Gupta, G.V.M.; Nair, S.

    Biolog plates were used to study the changes in the metabolic capabilities of bacterioplankton over a complete tidal cycle in a tropical ecosystem (Cochin Estuary, Kerala, India) along southwest coast of India. The pattern of utilization of carbon...

  11. Strong variability in bacterioplankton abundance and production in central and western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes; Ramaiah; Paul, J.T.; Sardessai; Jyothibabu; Gauns, M.

    to low or no nutrient injections into the surface, primary production in Bay of Bengal is reportedly low. As a consequence, the Bay of Bengal is considered as a region of low biological productivity. Along with many biological parameters, bacterioplankton...

  12. The sensitivity and stability of bacterioplankton community structure to wind-wave turbulence in a large, shallow, eutrophic lake

    OpenAIRE

    Zhou, Jian; Qin, Boqiang; Han, Xiaoxia; Jin, Decai; Wang, Zhiping

    2017-01-01

    Lakes are strongly influenced by wind-driven wave turbulence. The direct physical effects of turbulence on bacterioplankton community structure however, have not yet been addressed and remains poorly understood. To examine the stability of bacterioplankton communities under turbulent conditions, we simulated conditions in the field to evaluate the responses of the bacterioplankton community to physical forcing in Lake Taihu, using high-throughput sequencing and flow cytometry. A total of 4,52...

  13. Coupling bacterioplankton populations and environment to community function in coastal temperate waters

    DEFF Research Database (Denmark)

    Traving, S. J.; Bentzon-Tilia, Mikkel; Knudsen-Leerbeck, H.

    2016-01-01

    Bacterioplankton play a key role in marine waters facilitating processes important for carbon cycling. However, the influence of specific bacterial populations and environmental conditions on bacterioplankton community performance remains unclear. The aim of the present study was to identify...... surface waters over a full year indicated that specific bacterial populations were linked to measured functions. Namely, Synechococcus (Cyanobacteria) was strongly correlated with protease activity. Both function and community composition showed seasonal variation. However, the pattern of substrate...

  14. Bacterioplankton Populations within the Oxygen Minimum Zone of the Sargasso Sea

    Science.gov (United States)

    Schuler, G.; Parsons, R. J.; Johnson, R. J.

    2016-02-01

    Oxygen minimum zones are present throughout the world's oceans, and occur at depths between 200 to 1000m. Heterotrophic bacteria reduce the dissolved oxygen within this layer through respiration, while metabolizing falling particles. This report studied the bacterioplankton in the oxygen minimum zone at the BATS (Bermuda Atlantic Times-series Study) site from July 2014 until November 2014. Total bacterioplankton populations were enumerated through direct counts. In the transitional zone (400m-800m) of the oxygen minimum zone, a secondary bacterioplankton peak formed. This study used FISH (Fluorescent in situ hybridization) and CARD-FISH (Catalyzed Reporter Deposition-Fluorescent in situ hybridization) to enumerate specific bacterial and archaeal taxa. Crenarchaeota (including Thaumarchaeota) increased in abundance within the upper oxycline. Thaumarchaeota have the ammonia monooxygenase gene that oxidizes ammonium into nitrite in low oxygen conditions. Amplification of the amoA gene confirmed that ammonia oxidizing archaea (AOA) were present within the OMZ. Using Terminal Restriction Fragment Length Polymorphism (T-RFLP), the bacterial community structure showed high similarity based depth zones (0-80m, 160-600m, and 800-4500m). Niskin experiments determined that water collected at 800m had an exponential increase in bacterioplankton over time. While experimental design did not allow for oxygen levels to be maintained, the bacterioplankton community was predominantly bacteria with eubacteria positive cells making up 89.3% of the of the total bacterioplankton community by day 34. Improvements to the experimental design are required to determine which specific bacterial taxa caused this increase at 800m. This study suggests that there are factors other than oxygen influencing bacterioplankton populations at the BATS site, and more analysis is needed once the BATS data is available to determine the key drivers of bacterioplankton dynamics within the BATS OMZ.

  15. Community assembly processes underlying phytoplankton and bacterioplankton across a hydrologic change in a human-impacted river.

    Science.gov (United States)

    Isabwe, Alain; Yang, Jun R; Wang, Yongming; Liu, Lemian; Chen, Huihuang; Yang, Jun

    2018-02-27

    Although the influence of microbial community assembly processes on aquatic ecosystem function and biodiversity is well known, the processes that govern planktonic communities in human-impacted rivers remain largely unstudied. Here, we used multivariate statistics and a null model approach to test the hypothesis that environmental conditions and obstructed dispersal opportunities, dictate a deterministic community assembly for phytoplankton and bacterioplankton across contrasting hydrographic conditions in a subtropical mid-sized river (Jiulong River, southeast China). Variation partitioning analysis showed that the explanatory power of local environmental variables was larger than that of the spatial variables for both plankton communities during the dry season. During the wet season, phytoplankton community variation was mainly explained by local environmental variables, whereas the variance in bacterioplankton was explained by both environmental and spatial predictors. The null model based on Raup-Crick coefficients for both planktonic groups suggested little evidences of the stochastic processes involving dispersal and random distribution. Our results showed that hydrological change and landscape structure act together to cause divergence in communities along the river channel, thereby dictating a deterministic assembly and that selection exceeds dispersal limitation during the dry season. Therefore, to protect the ecological integrity of human-impacted rivers, watershed managers should not only consider local environmental conditions but also dispersal routes to account for the effect of regional species pool on local communities. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Phytoplankton Communities Exhibit a Stronger Response to Environmental Changes than Bacterioplankton in Three Subtropical Reservoirs.

    Science.gov (United States)

    Liu, Lemian; Yang, Jun; Lv, Hong; Yu, Xiaoqing; Wilkinson, David M; Yang, Jun

    2015-09-15

    The simultaneous analysis of multiple components of ecosystems is crucial for comprehensive studies of environmental changes in aquatic ecosystems, but such studies are rare. In this study, we analyzed simultaneously the bacterioplankton and phytoplankton communities in three Chinese subtropical reservoirs and compared the response of these two components to seasonal environmental changes. Time-lag analysis indicated that the temporal community dynamics of both bacterioplankton and phytoplankton showed significant directional changes, and variance partitioning suggested that the major reason was the gradual improvement of reservoir water quality from middle eutrophic to oligo-mesotrophic levels during the course of our study. In addition, we found a higher level of temporal stability or stochasticity in the bacterioplankton community than in the phytoplankton community. Potential explanations are that traits associated with bacteria, such as high abundance, widespread dispersal, potential for rapid growth rates, and rapid evolutionary adaptation, may underlie the different stability or stochasticity of bacterioplankton and phytoplankton communities to the environmental changes. In addition, the indirect response of bacterioplankton to nitrogen and phosphorus may result in the fact that environmental deterministic selection was stronger for the phytoplankton than for the bacterioplankton communities.

  17. A comparative hierarchical analysis of bacterioplankton and biofilm metacommunity structure in an interconnected pond system.

    Science.gov (United States)

    Souffreau, Caroline; Busschaert, Pieter; Denis, Carla; Van Wichelen, Jeroen; Lievens, Bart; Vyverman, Wim; De Meester, Luc

    2018-03-01

    It is unknown whether bacterioplankton and biofilm communities are structured by the same ecological processes, and whether they influence each other through continuous dispersal (known as mass effects). Using a hierarchical sampling approach we compared the relative importance of ecological processes structuring the dominant fraction (relative abundance ≥0.1%) of bacterioplankton and biofilm communities from three microhabitats (open water, Nuphar and Phragmites sites) at within- and among-pond scale in a set of 14 interconnected shallow ponds. Our results demonstrate that while bacterioplankton and biofilm communities are highly distinct, a similar hierarchy of ecological processes is acting on them. For both community types, most variation in community composition was determined by pond identity and environmental variables, with no effect of space. The highest β-diversity within each community type was observed among ponds, while microhabitat type (Nuphar, Phragmites, open water) significantly influenced biofilm communities but not bacterioplankton. Mass effects among bacterioplankton and biofilm communities were not detected, as suggested by the absence of within-site covariation of biofilm and bacterioplankton communities. Both biofilm and plankton communities were thus highly structured by environmental factors (i.e., species sorting), with among-lake variation being more important than within-lake variation, whereas dispersal limitation and mass effects were not observed. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. Diversity of bacterioplankton in the surface seawaters of Drake Passage near the Chinese Antarctic station.

    Science.gov (United States)

    Xing, Mengxin; Li, Zhao; Wang, Wei; Sun, Mi

    2015-07-01

    The determination of relative abundances and distribution of different bacterial groups is a critical step toward understanding the functions of various bacteria and its surrounding environment. Few studies focus on the taxonomic composition and functional diversity of microbial communities in Drake Passage. In this study, marine bacterioplankton communities from surface seawaters at five locations in Drake Passage were examined by 16S rRNA gene sequence analyses. The results indicated that psychrophilic bacteria were the most abundant group in Drake Passage, and mainly made up of Bacillus, Aeromonas, Psychrobacter, Pseudomonas and Halomonas. Diversity analysis showed that surface seawater communities had no significant correlation with latitudinal gradient. Additionally, a clear difference among five surface seawater communities was evident, with 1.8% OTUs (only two) belonged to Bacillus consistent across five locations and 71% OTUs (80) existed in only one location. However, the few cosmopolitans had the largest population sizes. Our results support the hypothesis that the dominant bacterial groups appear to be analogous between geographical sites, but significant differences may be detected among rare bacterial groups. The microbial diversity of surface seawaters would be liable to be affected by environmental factors. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Away from darkness: a review on the effects of solar radiation on heterotrophic bacterioplankton activity

    Science.gov (United States)

    Ruiz-González, Clara; Simó, Rafel; Sommaruga, Ruben; Gasol, Josep M.

    2013-01-01

    Heterotrophic bacterioplankton are main consumers of dissolved organic matter (OM) in aquatic ecosystems, including the sunlit upper layers of the ocean and freshwater bodies. Their well-known sensitivity to ultraviolet radiation (UVR), together with some recently discovered mechanisms bacteria have evolved to benefit from photosynthetically available radiation (PAR), suggest that natural sunlight plays a relevant, yet difficult to predict role in modulating bacterial biogeochemical functions in aquatic ecosystems. Three decades of experimental work assessing the effects of sunlight on natural bacterial heterotrophic activity reveal responses ranging from high stimulation to total inhibition. In this review, we compile the existing studies on the topic and discuss the potential causes underlying these contrasting results, with special emphasis on the largely overlooked influences of the community composition and the previous light exposure conditions, as well as the different temporal and spatial scales at which exposure to solar radiation fluctuates. These intricate sunlight-bacteria interactions have implications for our understanding of carbon fluxes in aquatic systems, yet further research is necessary before we can accurately evaluate or predict the consequences of increasing surface UVR levels associated with global change. PMID:23734148

  20. Away from darkness: A review on the effects of solar radiation on heterotrophic bacterioplankton activity

    Directory of Open Access Journals (Sweden)

    CLARA eRUIZ GONZALEZ

    2013-05-01

    Full Text Available Heterotrophic bacterioplankton are main consumers of dissolved organic matter in aquatic ecosystems, including the sunlit upper layers of the ocean and freshwater bodies. Their well-known sensitivity to ultraviolet radiation (UVR, together with some recently discovered mechanisms bacteria have evolved to benefit from photosynthetically available radiation (PAR, suggest that natural sunlight plays a relevant, yet difficult to predict role in modulating bacterial biogeochemical functions in aquatic ecosystems. Three decades of experimental work assessing the effects of sunlight on natural bacterial heterotrophic activity reveal responses ranging from high stimulation to total inhibition. In this review, we compile the existing studies on the topic and discuss the potential causes underlying these contrasting results, with special emphasis on the largely overlooked influences of the community composition and the previous light exposure conditions, as well as the different temporal and spatial scales at which exposure to solar radiation fluctuates. These intricate sunlight-bacteria interactions have implications for our understanding of carbon fluxes in aquatic systems, yet further research is necessary before we can accurately evaluate or predict the consequences of increasing surface UVR levels associated with global change.

  1. Group tele-immersion:enabling natural interactions between groups at distant sites.

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Christine L. (Sandia National Laboratories, Livermore, CA); Stewart, Corbin (Sandia National Laboratories, Livermore, CA); Nashel, Andrew (University of North Carolina at Chapel Hill, Chapel Hill, NC)

    2005-08-01

    We present techniques and a system for synthesizing views for video teleconferencing between small groups. In place of replicating one-to-one systems for each pair of users, we create a single unified display of the remote group. Instead of performing dense 3D scene computation, we use more cameras and trade-off storage and hardware for computation. While it is expensive to directly capture a scene from all possible viewpoints, we have observed that the participants viewpoints usually remain at a constant height (eye level) during video teleconferencing. Therefore, we can restrict the possible viewpoint to be within a virtual plane without sacrificing much of the realism, and in cloning so we significantly reduce the number of required cameras. Based on this observation, we have developed a technique that uses light-field style rendering to guarantee the quality of the synthesized views, using a linear array of cameras with a life-sized, projected display. Our full-duplex prototype system between Sandia National Laboratories, California and the University of North Carolina at Chapel Hill has been able to synthesize photo-realistic views at interactive rates, and has been used to video conference during regular meetings between the sites.

  2. Community Composition and Diversity of Coastal Bacterioplankton Assemblages in Lakes Michigan, Erie, and Huron.

    Science.gov (United States)

    Olapade, Ola A

    2018-04-01

    The Laurentian Great Lakes, including Lakes Superior, Michigan, Huron, Erie, and Ontario, located in the eastern part of North America are considered the largest of freshwater lakes in the world; however, very little is known about the diversity and distribution of indigenous microbial assemblages within these vast bodies of freshwater systems. Therefore, to delineate the microbial structure and community composition in these aquatic environments, combinations of high-throughput sequencing and fluorescent in situ hybridization (FISH) approaches were utilized to quantitatively characterize the occurrence, diversity, and distribution of bacterioplankton assemblages in six different sites located along the coastal regions of Lakes Michigan, Huron, and Erie. Phylogenetic examination showed a diverse bacterial community belonging to 11 different taxonomic groups. Pyrosequencing results revealed that the majority of the sequences were clustered into four main groups, i.e., Proteobacteria, Bacteriodetes, Actinobacteria, and Cyanobacteria, while fluorescent in situ hybridization also showed the numerical dominance of members of the Gammaproteobacteria and the Cytophaga-Flavobacterium in the six lake sites examined. Overall, the assemblages were shown to be quite diverse in distribution among the lake sites examined, comprising mostly of various heterotrophic populations, with the exception of the Lake Erie-Sandusky Bay site with more than 50% domination by autotrophic Cyanobacteria. This indicates that combinations of factors including water chemistry and various anthropogenic disturbances as well as the lake morphometric characteristics are probably influencing the community structure and diversity of the bacterial assemblages within the systems.

  3. Temporal Analysis of Bacterioplankton Community Structure in the Northeastern Gulf of Mexico

    Science.gov (United States)

    Knight, K. T.; Moss, J. A.; Snyder, R.; Henriksson, N. L.; Jeffrey, W. H.

    2016-02-01

    Bacteria are found in all oceans around the globe and are vital to many processes in the ocean. Evidence shows that bacteria are a dominant taxa in the marine environment with both abundance and contribution to the biological processes. Resource availability and environmental parameters are both key factors in determining bacterioplankton growth and community structure. Understanding temporal changes in the microbial community structure in the Gulf of Mexico has the potential to shed new light on the transfer of energy into and out of the system as well as through higher trophic levels. A two-year seasonal study was conducted at a station 40 km south of Choctawhatchee Bay on the Florida Shelf in the Northeast Gulf of Mexico. Water column samples were collected from surface and bottom waters ( 90 m) and mid-water deep chlorophyll maxima when present. In addition to microbial diversity, chemical, physical, and biological environmental parameters such as production, nutrients, temperature, salinity, chlorophyll a, and bacterial counts were also taken. 16S rDNA clone libraries were used to analyze temporal patterns and community structure of bacteria at fourteen timepoints and compared to the environmental data. Community structure patterns were seasonal in nature. The primary factors driving community structure are under statistical analyses.

  4. Euphotic zone bacterioplankton sources major sedimentary bacteriohopanepolyols in the Holocene Black Sea

    Science.gov (United States)

    Blumenberg, Martin; Seifert, Richard; Kasten, Sabine; Bahlmann, Enno; Michaelis, Walter

    2009-02-01

    Bacteriohopanepolyols (BHPs) are lipid constituents of many bacterial groups. Geohopanoids, the diagenetic products, are therefore ubiquitous in organic matter of the geosphere. To examine the potential of BHPs as environmental markers in marine sediments, we investigated a Holocene sediment core from the Black Sea. The concentrations of BHPs mirror the environmental shift from a well-mixed lake to a stratified marine environment by a strong and gradual increase from low values (˜30 μg g -1 TOC) in the oldest sediments to ˜170 μg g -1 TOC in sediments representing the onset of a permanently anoxic water body at about 7500 years before present (BP). This increase in BHP concentrations was most likely caused by a strong increase in bacterioplanktonic paleoproductivity brought about by several ingressions of Mediterranean Sea waters at the end of the lacustrine stage (˜9500 years BP). δ 15N values coevally decreasing with increasing BHP concentrations may indicate a shift from a phosphorus- to a nitrogen-limited setting supporting growth of N 2-fixing, BHP-producing bacteria. In sediments of the last ˜3000 years BHP concentrations have remained relatively stable at about 50 μg g -1 TOC. The distributions of major BHPs did not change significantly during the shift from lacustrine (or oligohaline) to marine conditions. Tetrafunctionalized BHPs prevailed throughout the entire sediment core, with the common bacteriohopanetetrol and 35-aminobacteriohopanetriol and the rare 35-aminobacteriohopenetriol, so far only known from a purple non-sulfur α-proteobacterium, being the main components. Other BHPs specific to cyanobacteria and pelagic methanotrophic bacteria were also found but only in much smaller amounts. Our results demonstrate that BHPs from microorganisms living in deeper biogeochemical zones of marine water columns are underrepresented or even absent in the sediment compared to the BHPs of bacteria present in the euphotic zone. Obviously, the assemblage of

  5. Lifelong Learning from Natural Disasters: Transformative Group-Based Learning at Philippine Universities

    Science.gov (United States)

    Dahl, Kari Kragh Blume; Millora, Christopher Malagad

    2016-01-01

    This study explores reflective experience during transformative, group-based learning among university leaders following a natural disaster such as a typhoon in two Philippine universities. Natural disasters are recurrent phenomena in many parts of the world, but the literature largely ignores their impact on lifelong human learning, for instance…

  6. Naturally seeded versus planted ponderosa pine seedlings in group-selection openings

    Science.gov (United States)

    Philip M. McDonald; Gary Fiddler; Martin Ritchie; Paula Anderson

    2009-01-01

    The purpose of this article was to determine whether natural regeneration or planted seedlings should be used in group-selection openings. The answer dependson the survival and growth rate of both types of seedlings, and that could depend on the size of the openings and the effect of trees on their edge. In thisside-by-side study, the natural pine seedlings originated...

  7. Coupling Bacterioplankton Populations and Environment to Community Function in Coastal Temperate Waters.

    Science.gov (United States)

    Traving, Sachia J; Bentzon-Tilia, Mikkel; Knudsen-Leerbeck, Helle; Mantikci, Mustafa; Hansen, Jørgen L S; Stedmon, Colin A; Sørensen, Helle; Markager, Stiig; Riemann, Lasse

    2016-01-01

    Bacterioplankton play a key role in marine waters facilitating processes important for carbon cycling. However, the influence of specific bacterial populations and environmental conditions on bacterioplankton community performance remains unclear. The aim of the present study was to identify drivers of bacterioplankton community functions, taking into account the variability in community composition and environmental conditions over seasons, in two contrasting coastal systems. A Least Absolute Shrinkage and Selection Operator (LASSO) analysis of the biological and chemical data obtained from surface waters over a full year indicated that specific bacterial populations were linked to measured functions. Namely, Synechococcus ( Cyanobacteria ) was strongly correlated with protease activity. Both function and community composition showed seasonal variation. However, the pattern of substrate utilization capacity could not be directly linked to the community dynamics. The overall importance of dissolved organic matter (DOM) parameters in the LASSO models indicate that bacterioplankton respond to the present substrate landscape, with a particular importance of nitrogenous DOM. The identification of common drivers of bacterioplankton community functions in two different systems indicates that the drivers may be of broader relevance in coastal temperate waters.

  8. Using Opinions and Knowledge to Identify Natural Groups of Gambling Employees.

    Science.gov (United States)

    Gray, Heather M; Tom, Matthew A; LaPlante, Debi A; Shaffer, Howard J

    2015-12-01

    Gaming industry employees are at higher risk than the general population for health conditions including gambling disorder. Responsible gambling training programs, which train employees about gambling and gambling-related problems, might be a point of intervention. However, such programs tend to use a "one-size-fits-all" approach rather than multiple tiers of instruction. We surveyed employees of one Las Vegas casino (n = 217) and one online gambling operator (n = 178) regarding their gambling-related knowledge and opinions prior to responsible gambling training, to examine the presence of natural knowledge groups among recently hired employees. Using k-means cluster analysis, we observed four natural groups within the Las Vegas casino sample and two natural groups within the online operator sample. We describe these natural groups in terms of opinion/knowledge differences as well as distributions of demographic/occupational characteristics. Gender and language spoken at home were correlates of cluster group membership among the sample of Las Vegas casino employees, but we did not identify demographic or occupational correlates of cluster group membership among the online gambling operator employees. Gambling operators should develop more sophisticated training programs that include instruction that targets different natural knowledge groups.

  9. Natural Interactions in Artifical Situations: Focus Groups as an Active Social Experiment

    DEFF Research Database (Denmark)

    Demant, Jakob

    2012-01-01

    This chapter discuss the question of how the validity of focus group data can be reframed when approaching focus groups as social experiments in a science and technology approach. By using this frame we first of all comes to perceive the focus group discussion as an artificial situation, while...... the interactions going on in the group can be described as natural occurring data (cf. Silverman, 2007). Thus this approach comes to terms with some of the problems addressed within both positivistic as well as constructivist uses of focus group methods. Secondly, framing focus groups as social experiments also...

  10. Opportunity for natural selection among five population groups of Manipur, North East India.

    Science.gov (United States)

    Asghar, M; Meitei, S Y; Luxmi, Y; Achoubi, N; Meitei, K S; Murry, B; Sachdeva, M P; Saraswathy, K N

    2014-01-01

    Opportunity for natural selection among five population groups of Manipur in comparison with other North East Indian population has been studied. Crow's index as well as Johnston and Kensinger's index for natural selection were calculated based on differential fertility and mortality. The mortality component was found to be lower compared to fertility component in all the populations which may attribute to comparatively improved and easily accessible health care facilities. However, different selection pressures, artificial and natural, seem to be influencing the selection intensity through induced abortion and spontaneous abortion among the two non-tribal migrant groups: Bamon and Muslims, respectively. This study highlights the probable interaction of artificial and natural selection in determining the evolutionary fate of any population group.

  11. Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study

    Directory of Open Access Journals (Sweden)

    U. Riebesell

    2013-01-01

    Full Text Available The effect of elevated seawater carbon dioxide (CO2 on the activity of a natural bacterioplankton community in an Arctic fjord system was investigated by a mesocosm perturbation study in the frame of the European Project on Ocean Acidification (EPOCA. A pCO2 range of 175–1085 μatm was set up in nine mesocosms deployed in the Kongsfjorden (Svalbard. The activity of natural extracellular enzyme assemblages increased in response to acidification. Rates of β-glucosidase and leucine-aminopeptidase increased along the gradient of mesocosm pCO2. A decrease in seawater pH of 0.5 units almost doubled rates of both enzymes. Heterotrophic bacterial activity was closely coupled to phytoplankton productivity in this experiment. The bacterioplankton community responded to rising chlorophyll a concentrations after a lag phase of only a few days with increasing protein production and extracellular enzyme activity. Time-integrated primary production and bacterial protein production were positively correlated, strongly suggesting that higher amounts of phytoplankton-derived organic matter were assimilated by heterotrophic bacteria at increased primary production. Primary production increased under high pCO2 in this study, and it can be suggested that the efficient heterotrophic carbon utilisation had the potential to counteract the enhanced autotrophic CO2 fixation. However, our results also show that beneficial pCO2-related effects on bacterial activity can be mitigated by the top-down control of bacterial abundances in natural microbial communities.

  12. Changes of bacterioplankton apparent species richness in two ornamental fish aquaria.

    Science.gov (United States)

    Vlahos, Nikolaos; Kormas, Konstantinos Ar; Pachiadaki, Maria G; Meziti, Alexandra; Hotos, George N; Mente, Eleni

    2013-12-01

    We analysed the 16S rRNA gene diversity within the bacterioplankton community in the water column of the ornamental fish Pterophyllum scalare and Archocentrus nigrofasciatus aquaria during a 60-day growth experiment in order to detect any dominant bacterial species and their possible association with the rearing organisms. The basic physical and chemical parameters remained stable but the bacterial community at 0, 30 and 60 days showed marked differences in bacterial cell abundance and diversity. We found high species richness but no dominant phylotypes were detected. Only few of the phylotypes were found in more than one time point per treatment and always with low relative abundance. The majority of the common phylotypes belonged to the Proteobacteria phylum and were closely related to Acinetobacter junii, Pseudomonas sp., Nevskia ramosa, Vogesella perlucida, Chitinomonas taiwanensis, Acidovorax sp., Pelomonas saccharophila and the rest belonged to the α-Proteobacteria, Bacteroidetes, Actinobacteria, candidate division OP11 and one unaffiliated group. Several of these phylotypes were closely related to known taxa including Sphingopyxis chilensis, Flexibacter aurantiacus subsp. excathedrus and Mycobacterium sp. Despite the high phylogenetic diversity most of the inferred ecophysiological roles of the found phylotypes are related to nitrogen metabolism, a key process for fish aquaria.

  13. Susceptibility of bacterioplankton to nutrient enrichment of oligotrophic and ultraoligotrophic lake waters

    Directory of Open Access Journals (Sweden)

    Beatriz MODENUTTI

    2008-08-01

    Full Text Available We carried out laboratory experiments in one ultraoligotrophic pristine Andean lake (Lake Gutiérrez, Argentina and in one subalpine lake that is now at the edge of the oligo- to mesotrophic condition (Lake Maggiore, Italy. Lake water was amended with phosphorus (+P, organic carbon (+C, alone or in combination (+CP, to test for short-term changes (48 hours in bacteria activity and community structure (CARD FISH. Experiments were carried out in spring and summer. Results showed that bacterial production increased in the +CP treatment in both lakes, and in the +P treatment in the ultroligotrophic lake. In both lakes the bacterial activity increased more rapidly in summer (within 24 hours. Bacteria composition changed in both seasons in all the treatments. At the beginning of the experiments the subclass of β-Proteobacteria dominated both lakes, while γ-Proteobacteria showed higher percentage in spring in Lake Maggiore and in summer in Lake Gutiérrez. After incubation, in spring and in particular in the +CP treatment, we observed an increase in the relative importance of γ-Proteobacteria in both lakes, whereas in Lake Maggiore this group declined in the summer experiments following an increase in β-Proteobacteria. All our results indicate the different response of bacterioplankton in systems at the edges of the oligotrophic range.

  14. The study of bacterioplankton dynamics in the Berlengas Archipelago (West coast of Portugal by applying the HJ-biplot method

    Directory of Open Access Journals (Sweden)

    Susana Mendes

    2009-01-01

    Full Text Available The relationship between bacterioplankton and environmental forcing in the Berlengas Archipelago (Western Coast of Portugal were studied between February 2006 and February 2007 in two sampling stations: Berlenga and Canal, using an HJ-biplot. The HJ-biplot showed a simultaneous display of the three main metabolic groups of bacteria involved in carbon cycling (aerobic heterotrophic bacteria, sulphate-reducing bacteria and nitrate-reducing bacteria and environmental parameters, in low dimensions. Our results indicated thatbacterial dynamics are mainly affected by temporal gradients (seasonal gradients with a clear winter versus summer opposition, and less by the spatial structure (Berlenga and Canal. The yearly variation in the abundance of aerobic heterotrophic bacteria were positively correlated with those in chlorophyll a concentration, whereas ammonium concentration and temperature decreased with increasing phosphates and nitrites concentration. The relationship between aerobic heterotrophic bacteria, chlorophyll a and ammonium reveals that phytoplankton is an important source of organic substrates for bacteria.

  15. Spatio-temporal patterns of bacterioplankton production and community composition related to phytoplankton composition and protistan bacterivory in a dam reservoir

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Horňák, Karel; Jezbera, Jan; Nedoma, Jiří; Znachor, Petr; Hejzlar, Josef; Seďa, Jaromír

    2008-01-01

    Roč. 51, č. 3 (2008), s. 249-262 ISSN 0948-3055 R&D Projects: GA ČR(CZ) GA206/08/0015; GA ČR(CZ) GA206/05/0007; GA AV ČR(CZ) 1QS600170504 Institutional research plan: CEZ:AV0Z60170517 Keywords : bacterioplankton composition and production * algal-bacterial relationships * extracellular phytoplankton production * protistan bacterivory * phytoplankton community * reservoir * betaproteobacterial groups Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.190, year: 2008

  16. Global patterns of marine bacterioplankton diversity and characterisation of bioactive Vibrionaceae isolates

    DEFF Research Database (Denmark)

    Wietz, Matthias

    The purpose of the present study was to analyze the composition of marine bacterial communities around the world, and to investigate bacterial isolates regarding the production of antibiotics. This included molecular analyses of marine bacterioplankton, as well as culture-based studies of marine...... bacterial isolates with antagonistic activity. The work was based on samples collected during the Galathea 3 and LOMROG-II marine research expeditions that have explored many different oceanic regions worldwide. A molecular survey of marine bacterioplankton at 24 worldwide stations investigated...... not produce andrimid and have different biosynthetic temperature optima suggested that V. coralliilyticus may comprise different subspecies with different niches. In summary, the present study shows biogeographical patterns of marine bacterioplankton on a global scale. In addition, the thesis work has...

  17. Sedimentological and Stratigraphic Controls on Natural Fracture Distribution in Wajid Group, SW Saudi Arabia

    Science.gov (United States)

    Benaafi, Mohammed; Hariri, Mustafa; Abdullatif, Osman; Makkawi, Mohammed; Korvin, Gabor

    2016-04-01

    The Cambro-Permian Wajid Group, SW Saudi Arabia, is the main groundwater aquifer in Wadi Al-Dawasir and Najran areas. In addition, it has a reservoir potentiality for oil and natural gas in Rub' Al-Khali Basin. Wajid Group divided into four formations, ascending Dibsiyah, Sanamah, Khussyayan and Juwayl. They are mainly sandstone and exposed in an area extend from Wadi Al-Dawasir southward to Najran city and deposited within fluvial, shallow marine and glacial environments. This study aims to investigate the sedimentological and stratigraphic controls on the distribution of natural fractures within Wajid Group outcrops. A scanline sampling method was used to study the natural fracture network within Wajid Group outcrops, where the natural fractures were measured and characterized in 12 locations. Four regional natural fracture sets were observed with mean strikes of 050o, 075o, 345o, and 320o. Seven lithofacies characterized the Wajid Group at these locations and include fine-grained sandstone, coarse to pebbly sandstone, cross-bedded sandstone, massive sandstone, bioturbated sandstone, conglomerate sandstone, and conglomerate lithofacies. We found that the fine-grained and small scale cross-bedded sandstones lithofacies are characterized by high fracture intensity. In contrast, the coarse-grained sandstone and conglomerate lithofacies have low fracture intensity. Therefore, the relative fracture intensity and spacing of natural fractures within Wajid Group in the subsurface can be predicted by using the lithofacies and their depositional environments. In terms of stratigraphy, we found that the bed thickness and the stratigraphic architecture are the main controls on fractures intensity. The outcomes of this study can help to understand and predict the natural fracture distribution within the subsurface fractured sandstone hosting groundwater and hydrocarbon in Wajid and Rub' Al-Khali Basins. Hence, the finding of this study might help to explore and develop the

  18. Distribution, Community Composition, and Potential Metabolic Activity of Bacterioplankton in an Urbanized Mediterranean Sea Coastal Zone.

    Science.gov (United States)

    Richa, Kumari; Balestra, Cecilia; Piredda, Roberta; Benes, Vladimir; Borra, Marco; Passarelli, Augusto; Margiotta, Francesca; Saggiomo, Maria; Biffali, Elio; Sanges, Remo; Scanlan, David J; Casotti, Raffaella

    2017-09-01

    Bacterioplankton are fundamental components of marine ecosystems and influence the entire biosphere by contributing to the global biogeochemical cycles of key elements. Yet, there is a significant gap in knowledge about their diversity and specific activities, as well as environmental factors that shape their community composition and function. Here, the distribution and diversity of surface bacterioplankton along the coastline of the Gulf of Naples (GON; Italy) were investigated using flow cytometry coupled with high-throughput sequencing of the 16S rRNA gene. Heterotrophic bacteria numerically dominated the bacterioplankton and comprised mainly Alphaproteobacteria , Gammaproteobacteria , and Bacteroidetes Distinct communities occupied river-influenced, coastal, and offshore sites, as indicated by Bray-Curtis dissimilarity, distance metric (UniFrac), linear discriminant analysis effect size (LEfSe), and multivariate analyses. The heterogeneity in diversity and community composition was mainly due to salinity and changes in environmental conditions across sites, as defined by nutrient and chlorophyll a concentrations. Bacterioplankton communities were composed of a few dominant taxa and a large proportion (92%) of rare taxa (here defined as operational taxonomic units [OTUs] accounting for bacterioplankton in coastal zones is of critical importance, considering that these areas are highly productive and anthropogenically impacted. Their richness and evenness, as well as their potential activity, are very important to assess ecosystem health and functioning. Here, we investigated bacterial distribution, community composition, and potential metabolic activity in the GON, which is an ideal test site due to its heterogeneous environment characterized by a complex hydrodynamics and terrestrial inputs of varied quantities and quality. Our study demonstrates that bacterioplankton communities in this region are highly diverse and strongly regulated by a combination of

  19. Drivers of coastal bacterioplankton community diversity and structure along a nutrient gradient in the East China Sea

    Science.gov (United States)

    He, Jiaying; Wang, Kai; Xiong, Jinbo; Guo, Annan; Zhang, Demin; Fei, Yuejun; Ye, Xiansen

    2017-04-01

    Anthropogenic nutrient discharge poses widespread threats to coastal ecosystems and has increased environmental gradients from coast to sea. Bacterioplankton play crucial roles in coastal biogeochemical cycling, and a variety of factors affect bacterial community diversity and structure. We used 16S rRNA gene pyrosequencing to investigate the spatial variation in bacterial community composition (BCC) across five sites on a coast-offshore gradient in the East China Sea. Overall, bacterial alpha-diversity did not differ across sites, except that richness and phylogenetic diversity were lower in the offshore sites, and the highest alpha-diversity was found in the most landward site, with Chl-a being the main factor. BCCs generally clustered into coastal and offshore groups. Chl-a explained 12.3% of the variation in BCCs, more than that explained by either the physicochemical (5.7%) or spatial (8.5%) variables. Nutrients (particularly nitrate and phosphate), along with phytoplankton abundance, were more important than other physicochemical factors, co-explaining 20.0% of the variation in BCCs. Additionally, a series of discriminant families (primarily affiliated with Gammaproteobacteria and Alphaproteobacteria), whose relative abundances correlated with Chl-a, DIN, and phosphate concentrations, were identified, implying their potential to indicate phytoplankton blooms and nutrient enrichment in this marine ecosystem. This study provides insight into bacterioplankton response patterns along a coast-offshore gradient, with phytoplankton abundance increasing in the offshore sites. Time-series sampling across multiple transects should be performed to determine the seasonal and spatial patterns in bacterial diversity and community structure along this gradient.

  20. Photo-degradation effect on dissolved organic carbon availability to bacterioplankton in a lake in the upper Paraná river floodplain - doi: 10.4025/actascibiolsci.v35i1.11054

    Directory of Open Access Journals (Sweden)

    Júlio César Rodrigues de Azevedo

    2012-12-01

    Full Text Available Dissolved organic carbon (DOC is nowadays recognized as the main substrate and source of energy for aquatic microbial community. The great part of available organic carbon for bacterioplankton might be formed after photolytic degradation of humic material, which constitutes the major part of DOC in almost all natural waters. The effects of DOC photo-degradation were evaluated, as was its utilization by bacterioplankton, through a two-step experiment, one involving photo-degradation of DOC and the other bacterial growth on the photo-degraded substrate. Photo-degradation was responsible for the consumption of 19% of DOC, reduced SUVA254, an increase in the E2/E3 and E3/E4 ratios, in addition to modifications in the fluorescence spectra that indicated a rise in the labile fraction of DOC. However, these alterations on DOC were not reflected in differences in bacterioplankton growth, as shown by the fact that there were no significant differences in density, biomass, bacterial production, bacterial respiration and bacterial growth efficiency between treatment and control.  

  1. The Effect of Dreissena polymorpha on Bacterioplankton, Nematode Fauna and their Relations to Environmental Factors in Ogosta Reservoir (Danube Basin

    Directory of Open Access Journals (Sweden)

    Kalcheva Hristina

    2016-04-01

    Full Text Available Spatial, seasonal, and annual bacterioplankton dynamics in recently infested by the species Dreissena polymorpha Ogosta Reservoir were studied for the first time during three year period. Bacterioplankton total number was higher in spring in ecotone zones, than in summer at thermocline. NH4-N, PO4-P, turbidity, dissolved oxygen, COD and chlorophyll-a correlate positively, while transparency and Ca2+ negatively with bacteria. Nematode species composition, included 22 species studied (13 rarely found and Rhabditis brevispina new for Bulgaria belonging to nine families. The D. polymorpha impact is positive on nematodes and phytoplankton, negative on zooplankton and bacterioplankton, but weak positive on larger bacteria, rods and attached bacteria.

  2. Ability Grouping's Effects on Grades and the Attainment of Higher Education: A Natural Experiment

    Science.gov (United States)

    Bygren, Magnus

    2016-01-01

    To test the effect of ability grouping on grades and the attainment of higher education, this study examines a naturally occurring experiment--an admission reform that dramatically increased ability sorting between schools in the municipality of Stockholm. Following six cohorts of students (N = 79,020) from the age of 16 to 26, I find a mean…

  3. Communicating the Nature of Science through "The Big Bang Theory": Evidence from a Focus Group Study

    Science.gov (United States)

    Li, Rashel; Orthia, Lindy A.

    2016-01-01

    In this paper, we discuss a little-studied means of communicating about or teaching the nature of science (NOS)--through fiction television. We report some results of focus group research which suggest that the American sitcom "The Big Bang Theory" (2007-present), whose main characters are mostly working scientists, has influenced…

  4. Walking for Well-Being: Are Group Walks in Certain Types of Natural Environments Better for Well-Being than Group Walks in Urban Environments?

    OpenAIRE

    Marselle, Melissa R.; Irvine, Katherine N.; Warber, Sara L.

    2013-01-01

    The benefits of walking in natural environments for well-being are increasingly understood. However, less well known are the impacts different types of natural environments have on psychological and emotional well-being. This cross-sectional study investigated whether group walks in specific types of natural environments were associated with greater psychological and emotional well-being compared to group walks in urban environments. Individuals who frequently attended a walking group once a ...

  5. Interactions between hydrology and water chemistry shape bacterioplankton biogeography across boreal freshwater networks.

    Science.gov (United States)

    Niño-García, Juan Pablo; Ruiz-González, Clara; Del Giorgio, Paul A

    2016-07-01

    Disentangling the mechanisms shaping bacterioplankton communities across freshwater ecosystems requires considering a hydrologic dimension that can influence both dispersal and local sorting, but how the environment and hydrology interact to shape the biogeography of freshwater bacterioplankton over large spatial scales remains unexplored. Using Illumina sequencing of the 16S ribosomal RNA gene, we investigate the large-scale spatial patterns of bacterioplankton across 386 freshwater systems from seven distinct regions in boreal Québec. We show that both hydrology and local water chemistry (mostly pH) interact to shape a sequential structuring of communities from highly diverse assemblages in headwater streams toward larger rivers and lakes dominated by fewer taxa. Increases in water residence time along the hydrologic continuum were accompanied by major losses of bacterial richness and by an increased differentiation of communities driven by local conditions (pH and other related variables). This suggests that hydrology and network position modulate the relative role of environmental sorting and mass effects on community assembly by determining both the time frame for bacterial growth and the composition of the immigrant pool. The apparent low dispersal limitation (that is, the lack of influence of geographic distance on the spatial patterns observed at the taxonomic resolution used) suggests that these boreal bacterioplankton communities derive from a shared bacterial pool that enters the networks through the smallest streams, largely dominated by mass effects, and that is increasingly subjected to local sorting of species during transit along the hydrologic continuum.

  6. Annual dynamics of North Sea bacterioplankton: seasonal variability superimposes short-term variation.

    Science.gov (United States)

    Lucas, Judith; Wichels, Antje; Teeling, Hanno; Chafee, Meghan; Scharfe, Mirco; Gerdts, Gunnar

    2015-09-01

    The dynamics of coastal marine microbial communities are driven by seasonally changing abiotic and biotic factors as well as by rapidly occurring short-term changes such as river fresh water influxes or phytoplankton blooms. We examined the variability of the free-living bacterioplankton at Helgoland Roads (German Bight, North Sea) over a period of one year with high temporal and taxonomic resolution to reveal variation patterns and main influencing factors. 16S rRNA gene tag sequencing of the bacterioplankton community hints at annual recurrence and resilience of few main taxa belonging to Alphaproteobacteria, Betaproteobacteria, Flavobacteriia, Acidimicrobiia and Thermoplasmata. Multiple regression analyses with various environmental factors revealed changes in water current patterns and resulting phytoplankton blooms as the main driving factors for short-term variation and temperature as the overlying factor for seasonal variation. Comparison of bacterioplankton successions during spring and summer phytoplankton blooms revealed the same dominating Flavobacteriia operational taxonomic units (OTUs) but shifts in Roseobacter related OTUs (Alphaproteobacteria) and SAR92 clade members (Gammaproteobacteria). Network analysis suggests that during spring and summer phytoplankton blooms temperature-dependent guilds are formed. In conclusion, our data imply that short-term bacterioplankton successions in response to phytoplankton blooms are indirectly affected by temperature, which is a major niche-defining factor in the German Bight. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. INFLUENCE OF LIGHT ON BACTERIOPLANKTON PRODUCTION AND RESPIRATION IN A SUBTROPICAL CORAL REEF

    Science.gov (United States)

    The influence of sunlight on bacterioplankton production (14C-leucine (Leu) and 3H-thymidine (TdR) incorporation; changes in cell abundances) and O2 consumption was investigated in a shallow subtropical coral reef located near Key Largo, Florida. Quartz (light) and opaque (dark) ...

  8. BACTERIOPLANKTON DYNAMICS IN PENSACOLA BAY, FL, USA: ROLE OF PHYTOPLANKTON AND DETRIAL CARBON SOURCES

    Science.gov (United States)

    Bacterioplankton Dynamics in Pensacola Bay, FL, USA: Role of Phytoplankton and Detrital Carbon Sources (Abstract). To be presented at the16th Biennial Conference of the Estuarine Research Foundation, ERF 2001: An Estuarine Odyssey, 4-8 November 2001, St. Pete Beach, FL. 1 p. (ER...

  9. Nutrient enrichment during shrimp cultivation alters bacterioplankton assemblies and destroys community stability.

    Science.gov (United States)

    Yang, Wen; Zheng, Cheng; Zheng, Zhongming; Wei, Yiming; Lu, Kaihong; Zhu, Jinyong

    2018-07-30

    Intensive shrimp farming is generally accompanied by nutrient enrichment and gradual eutrophication, which impose major threats to shrimp culture ecosystems. However, little is known about how the bacterioplankton community in a rearing environment responds to increased eutrophication during shrimp culture processes. In this study, we used the MiSeq sequencing technique to explore the impacts of nutrient enrichment on the assembly and stability of the bacterioplankton community. Our results showed that magnitudes of the changes in the bacterioplankton community compositions (BCCs) and diversity were closely associated with eutrophication level. Moreover, a phylogenetic-based mean nearest taxon distance (MNTD) analysis revealed that increased eutrophication significantly (P bacterioplankton ecological processes from deterministic to stochastic. A structural equation model showed that eutrophication indicators affected the BCCs either directly by controlling resources or indirectly by modifying other environmental variables of the shrimp ponds in complex pathways. Furthermore, association network comparisons revealed that nutrient enrichment increased the complexity of interspecies interactions and the proportion of cooperative interactions and decreased the proportion of generalists, which suggest that nutrient enrichment destroyed the community stability. These findings suggest that minimizing nutrient pollution, especially at the end of cultivation, could be an important management tool for establishing a microbially mature water system. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. A metagenomic assessment of winter and summer bacterioplankton from Antarctica Peninsula coastal surface waters.

    Science.gov (United States)

    Grzymski, Joseph J; Riesenfeld, Christian S; Williams, Timothy J; Dussaq, Alex M; Ducklow, Hugh; Erickson, Matthew; Cavicchioli, Ricardo; Murray, Alison E

    2012-10-01

    Antarctic surface oceans are well-studied during summer when irradiance levels are high, sea ice is melting and primary productivity is at a maximum. Coincident with this timing, the bacterioplankton respond with significant increases in secondary productivity. Little is known about bacterioplankton in winter when darkness and sea-ice cover inhibit photoautotrophic primary production. We report here an environmental genomic and small subunit ribosomal RNA (SSU rRNA) analysis of winter and summer Antarctic Peninsula coastal seawater bacterioplankton. Intense inter-seasonal differences were reflected through shifts in community composition and functional capacities encoded in winter and summer environmental genomes with significantly higher phylogenetic and functional diversity in winter. In general, inferred metabolisms of summer bacterioplankton were characterized by chemoheterotrophy, photoheterotrophy and aerobic anoxygenic photosynthesis while the winter community included the capacity for bacterial and archaeal chemolithoautotrophy. Chemolithoautotrophic pathways were dominant in winter and were similar to those recently reported in global 'dark ocean' mesopelagic waters. If chemolithoautotrophy is widespread in the Southern Ocean in winter, this process may be a previously unaccounted carbon sink and may help account for the unexplained anomalies in surface inorganic nitrogen content.

  11. Diel changes in bacteriochlorophyll a concentration suggest rapid bacterioplankton cycling in the Baltic Sea

    Czech Academy of Sciences Publication Activity Database

    Koblížek, Michal; Ston-Egiert, J.; Sagan, S.; Kolber, Z. S.

    2005-01-01

    Roč. 51, - (2005), s. 353-361 ISSN 0168-6496 R&D Projects: GA ČR GP206/03/P079; GA MŠk LN00A141 Institutional research plan: CEZ:AV0Z5020903 Keywords : Aerobic anoxygenic photoheterotrophs * Bacterial mortality * Bacterioplankton turnover Subject RIV: EE - Microbiology, Virology Impact factor: 2.787, year: 2005

  12. Influence of salinity on bacterioplankton communities from the Brazilian rain forest to the coastal Atlantic Ocean.

    Directory of Open Access Journals (Sweden)

    Cynthia B Silveira

    Full Text Available BACKGROUND: Planktonic bacteria are recognized as important drivers of biogeochemical processes in all aquatic ecosystems, however, the taxa that make up these communities are poorly known. The aim of this study was to investigate bacterial communities in aquatic ecosystems at Ilha Grande, Rio de Janeiro, Brazil, a preserved insular environment of the Atlantic rain forest and how they correlate with a salinity gradient going from terrestrial aquatic habitats to the coastal Atlantic Ocean. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed chemical and microbiological parameters of water samples and constructed 16S rRNA gene libraries of free living bacteria obtained at three marine (two coastal and one offshore and three freshwater (water spring, river, and mangrove environments. A total of 836 sequences were analyzed by MOTHUR, yielding 269 freshwater and 219 marine operational taxonomic units (OTUs grouped at 97% stringency. Richness and diversity indexes indicated that freshwater environments were the most diverse, especially the water spring. The main bacterial group in freshwater environments was Betaproteobacteria (43.5%, whereas Cyanobacteria (30.5%, Alphaproteobacteria (25.5%, and Gammaproteobacteria (26.3% dominated the marine ones. Venn diagram showed no overlap between marine and freshwater OTUs at 97% stringency. LIBSHUFF statistics and PCA analysis revealed marked differences between the freshwater and marine libraries suggesting the importance of salinity as a driver of community composition in this habitat. The phylogenetic analysis of marine and freshwater libraries showed that the differences in community composition are consistent. CONCLUSIONS/SIGNIFICANCE: Our data supports the notion that a divergent evolutionary scenario is driving community composition in the studied habitats. This work also improves the comprehension of microbial community dynamics in tropical waters and how they are structured in relation to physicochemical

  13. Influence of salinity on bacterioplankton communities from the Brazilian rain forest to the coastal Atlantic Ocean.

    Science.gov (United States)

    Silveira, Cynthia B; Vieira, Ricardo P; Cardoso, Alexander M; Paranhos, Rodolfo; Albano, Rodolpho M; Martins, Orlando B

    2011-03-09

    Planktonic bacteria are recognized as important drivers of biogeochemical processes in all aquatic ecosystems, however, the taxa that make up these communities are poorly known. The aim of this study was to investigate bacterial communities in aquatic ecosystems at Ilha Grande, Rio de Janeiro, Brazil, a preserved insular environment of the Atlantic rain forest and how they correlate with a salinity gradient going from terrestrial aquatic habitats to the coastal Atlantic Ocean. We analyzed chemical and microbiological parameters of water samples and constructed 16S rRNA gene libraries of free living bacteria obtained at three marine (two coastal and one offshore) and three freshwater (water spring, river, and mangrove) environments. A total of 836 sequences were analyzed by MOTHUR, yielding 269 freshwater and 219 marine operational taxonomic units (OTUs) grouped at 97% stringency. Richness and diversity indexes indicated that freshwater environments were the most diverse, especially the water spring. The main bacterial group in freshwater environments was Betaproteobacteria (43.5%), whereas Cyanobacteria (30.5%), Alphaproteobacteria (25.5%), and Gammaproteobacteria (26.3%) dominated the marine ones. Venn diagram showed no overlap between marine and freshwater OTUs at 97% stringency. LIBSHUFF statistics and PCA analysis revealed marked differences between the freshwater and marine libraries suggesting the importance of salinity as a driver of community composition in this habitat. The phylogenetic analysis of marine and freshwater libraries showed that the differences in community composition are consistent. Our data supports the notion that a divergent evolutionary scenario is driving community composition in the studied habitats. This work also improves the comprehension of microbial community dynamics in tropical waters and how they are structured in relation to physicochemical parameters. Furthermore, this paper reveals for the first time the pristine

  14. Alkane Hydroxylase Gene (alkB Phylotype Composition and Diversity in Northern Gulf of Mexico Bacterioplankton

    Directory of Open Access Journals (Sweden)

    Conor Blake Smith

    2013-12-01

    Full Text Available Natural and anthropogenic activities introduce alkanes into marine systems where they are degraded by alkane hydroxylases expressed by phylogenetically diverse bacteria. Partial sequences for alkB, one of the structural genes of alkane hydroxylase, have been used to assess the composition of alkane-degrading communities, and to determine their responses to hydrocarbon inputs. We present here the first spatially extensive analysis of alkB in bacterioplankton of the northern Gulf of Mexico (nGoM, a region that experiences numerous hydrocarbon inputs. We have analyzed 401 partial alkB gene sequences amplified from genomic extracts collected during March 2010 from 17 water column samples that included surface waters and bathypelagic depths. Previous analyses of 16S rRNA gene sequences for these and related samples have shown that nGoM bacterial community composition and structure stratify strongly with depth, with distinctly different communities above and below 100 m. Although we hypothesized that alkB gene sequences would exhibit a similar pattern, PCA analyses of operational protein units (OPU indicated that community composition did not vary consistently with depth or other major physical-chemical variables. We observed 22 distinct OPUs, one of which was ubiquitous and accounted for 57% of all sequences. This OPU clustered with alkB sequences from known hydrocarbon oxidizers (e.g., Alcanivorax and Marinobacter. Some OPUs could not be associated with known alkane degraders, however, and perhaps represent novel hydrocarbon-oxidizing populations or genes. These results indicate that the capacity for alkane hydrolysis occurs widely in the nGoM, but that alkane degrader diversity varies substantially among sites and responds differently than bulk communities to physical-chemical variables.

  15. Phytoplankton relationship with bacterioplankton, dissolved carbohydrates and water characteristics in a subtropical coastal lagoon

    Directory of Open Access Journals (Sweden)

    Pablo S. Guimarães

    2013-10-01

    Full Text Available Release of carbohydrates by phytoplankton enhances microbial diversity, promoting associations between algae and heterotrophic organisms. Thus, this work aimed to characterise the dissolved carbohydrates at a Brazilian subtropical coastal lagoon (Merin lagoon, in addition to determining their relationships with environmental parameters and phyto/bacterioplankton communities over one year. We analysed the relationships among physical, chemical and biological parameters by a principal component analysis (PCA after normalisation of data as z scores. Chlorophyceae showed the highest richness, although Bacillariophyceae and Cyanophyceae showed the highest densities. These classes are essentially represented by centric diatoms (Aulacoseira cf. muzzanensis and filamentous cyanobacteria (Planktolyngbya limnetica and Planktolyngbya cf. contorta. Merin lagoon showed a strong seasonal behaviour for most of parameters and phytoplanktonic density was mainly correlated with temperature, specific conductance, phosphate and total bright sunshine duration. Only combined dissolved carbohydrates (CDCHOs were found and their main components were glucose (31.6%, mannose/xylose (20.6%, ribose (13.9%, arabinose (8.9% and galacturonic acid (8.1%. The CDCHO amounts were higher in November, March-April and September and the December/January and July/August periods showed lower ones. Ribose was first detected only in the warm months and it gradually decreased with bacterial density. The carbohydrate concentration was coupled to phytoplanktonic density, except in December and January, when the bacterial density was increased. These results supported the significance of dissolved carbohydrates in associations with algae and bacteria in the freshwater planktonic environment. Our data reinforced the influence of phytoplankton community on the natural dissolved carbohydrate pool, besides the significance of such carbon source on the bacterial community dynamic.

  16. Polymer Electrolyte Prepared from Highly Deproteinized Natural Rubber Having Epoxy Group

    Science.gov (United States)

    Klinklai, W.; Kawahara, S.; Isono, Y.; Mizumo, T.; Yoshizawa, M.; Ohno, H.

    Deproteinized natural rubber having epoxy group (EDPNR) was applied to transport Li+ as a solid polymer electrolyte. The deproteinized natural rubber, incubated with proteolytic enzyme and surfactant, was subjected to epoxidation followed by oxidative depolymerization in latex stage. The resulting rubber was proved to be a liquid deproteinized natural rubber (LEDPNR) having polar epoxy groups, low Tg, low Mn and well-defined terminal units. Ionic conductivity of LEDPNR mixed with alkali metal salts was investigated through impedance analysis to clarify an effect of proteins present in the rubber. The ionic conductivity of the resulting LEDPNR depended on the kind of salts, their concentrations and temperature. The ionic conductivity of LEDPNR/lithium bis(trifluoromethan sulfonyl)imide (LiTFSI) was higher than that of LEDPNR/ lithium perchlorate (LiClO4). The difference in the ionic conductivity was attributed to the solubility of the salts as results of both high-resolution solid-state 13C-NMR spectroscopy and measurements of spin-lattice relaxation time. The conductivity of LEDPNR/LiTFSI was also dependent upon concentrations of LiTFSI and it reached the highest value at 20 wt%, which was different from the monotonic increase in the Li+ conductivity of liquid epoxidized natural rubber prepared from untreated natural rubber.

  17. Response of bacterioplankton communities to cadmium exposure in coastal water microcosms with high temporal variability.

    Science.gov (United States)

    Wang, Kai; Zhang, Demin; Xiong, Jinbo; Chen, Xinxin; Zheng, Jialai; Hu, Changju; Yang, Yina; Zhu, Jianlin

    2015-01-01

    Multiple anthropogenic disturbances to bacterial diversity have been investigated in coastal ecosystems, in which temporal variability in the bacterioplankton community has been considered a ubiquitous process. However, far less is known about the temporal dynamics of a bacterioplankton community responding to pollution disturbances such as toxic metals. We used coastal water microcosms perturbed with 0, 10, 100, and 1,000 μg liter(-1) of cadmium (Cd) for 2 weeks to investigate temporal variability, Cd-induced patterns, and their interaction in the coastal bacterioplankton community and to reveal whether the bacterial community structure would reflect the Cd gradient in a temporally varying system. Our results showed that the bacterioplankton community structure shifted along the Cd gradient consistently after a 4-day incubation, although it exhibited some resistance to Cd at low concentration (10 μg liter(-1)). A process akin to an arms race between temporal variability and Cd exposure was observed, and the temporal variability overwhelmed Cd-induced patterns in the bacterial community. The temporal succession of the bacterial community was correlated with pH, dissolved oxygen, NO3 (-)-N, NO2 (-)-N, PO4 (3-)-P, dissolved organic carbon, and chlorophyll a, and each of these parameters contributed more to community variance than Cd did. However, elevated Cd levels did decrease the temporal turnover rate of community. Furthermore, key taxa, affiliated to the families Flavobacteriaceae, Rhodobacteraceae, Erythrobacteraceae, Piscirickettsiaceae, and Alteromonadaceae, showed a high frequency of being associated with Cd levels during 2 weeks. This study provides direct evidence that specific Cd-induced patterns in bacterioplankton communities exist in highly varying manipulated coastal systems. Future investigations on an ecosystem scale across longer temporal scales are needed to validate the observed pattern. Copyright © 2015, American Society for Microbiology. All

  18. Coral and macroalgal exudates vary in neutral sugar composition and differentially enrich reef bacterioplankton lineages.

    Science.gov (United States)

    Nelson, Craig E; Goldberg, Stuart J; Wegley Kelly, Linda; Haas, Andreas F; Smith, Jennifer E; Rohwer, Forest; Carlson, Craig A

    2013-05-01

    Increasing algal cover on tropical reefs worldwide may be maintained through feedbacks whereby algae outcompete coral by altering microbial activity. We hypothesized that algae and coral release compositionally distinct exudates that differentially alter bacterioplankton growth and community structure. We collected exudates from the dominant hermatypic coral holobiont Porites spp. and three dominant macroalgae (one each Ochrophyta, Rhodophyta and Chlorophyta) from reefs of Mo'orea, French Polynesia. We characterized exudates by measuring dissolved organic carbon (DOC) and fractional dissolved combined neutral sugars (DCNSs) and subsequently tracked bacterioplankton responses to each exudate over 48 h, assessing cellular growth, DOC/DCNS utilization and changes in taxonomic composition (via 16S rRNA amplicon pyrosequencing). Fleshy macroalgal exudates were enriched in the DCNS components fucose (Ochrophyta) and galactose (Rhodophyta); coral and calcareous algal exudates were enriched in total DCNS but in the same component proportions as ambient seawater. Rates of bacterioplankton growth and DOC utilization were significantly higher in algal exudate treatments than in coral exudate and control incubations with each community selectively removing different DCNS components. Coral exudates engendered the smallest shift in overall bacterioplankton community structure, maintained high diversity and enriched taxa from Alphaproteobacteria lineages containing cultured representatives with relatively few virulence factors (VFs) (Hyphomonadaceae and Erythrobacteraceae). In contrast, macroalgal exudates selected for less diverse communities heavily enriched in copiotrophic Gammaproteobacteria lineages containing cultured pathogens with increased VFs (Vibrionaceae and Pseudoalteromonadaceae). Our results demonstrate that algal exudates are enriched in DCNS components, foster rapid growth of bacterioplankton and select for bacterial populations with more potential VFs than

  19. UK Natural Analogue Co-Ordinating Group: first annual progress report

    International Nuclear Information System (INIS)

    Hooker, P.J.; Chapman, N.A.

    1987-11-01

    The British Geological Survey is reponsible for co-ordinating the Department of the Environment's programme of natural analogue studies of radionuclide migration, a research programme that involved both UK and overseas sites. Co-ordination is achieved through the UK Natural Analogue Co-ordinating Group (NACG) which was established in October 1986. It has met three times to date and its function is to ensure that the different research projects have an integrated purpose aimed at improving and applying our understanding of natural geochemical processes in a way that will increase our confidence in long-term modelling predictions. Improved modelling prediction of radionuclide transport in the geosphere will directly benefit the performance and safety assessments of proposed radioactive waste repositories. (author)

  20. Responses of spatial-temporal dynamics of bacterioplankton community to large-scale reservoir operation: a case study in the Three Gorges Reservoir, China

    OpenAIRE

    Li, Zhe; Lu, Lunhui; Guo, Jinsong; Yang, Jixiang; Zhang, Jiachao; He, Bin; Xu, Linlin

    2017-01-01

    Large rivers are commonly regulated by damming, yet the effects of such disruption on bacterioplankton community structures have not been adequately studied. The aim of this study was to explore the biogeographical patterns present under dam regulation and to uncover the major drivers structuring bacterioplankton communities. Bacterioplankton assemblages in the Three Gorges Reservoir (TGR) were analyzed using Illumina Miseq sequencing by comparing seven sites located within the TGR before and...

  1. Freshwater bacterioplankton richness in oligotrophic lakes depends on nutrient availability rather than on species–area relationships

    OpenAIRE

    Logue, Jürg Brendan; Langenheder, Silke; Andersson, Anders F; Bertilsson, Stefan; Drakare, Stina; Lanzén, Anders; Lindström, Eva S

    2011-01-01

    A central goal in ecology is to grasp the mechanisms that underlie and maintain biodiversity and patterns in its spatial distribution can provide clues about those mechanisms. Here, we investigated what might determine the bacterioplankton richness (BR) in lakes by means of 454 pyrosequencing of the 16S rRNA gene. We further provide a BR estimate based upon a sampling depth and accuracy, which, to our knowledge, are unsurpassed for freshwater bacterioplankton communities. Our examination of 2...

  2. Time series analysis applied to construct US natural gas price functions for groups of states

    International Nuclear Information System (INIS)

    Kalashnikov, V.V.; Matis, T.I.; Perez-Valdes, G.A.

    2010-01-01

    The study of natural gas markets took a considerably new direction after the liberalization of the natural gas markets during the early 1990s. As a result, several problems and research opportunities arose for those studying the natural gas supply chain, particularly the marketing operations. Consequently, various studies have been undertaken about the econometrics of natural gas. Several models have been developed and used for different purposes, from descriptive analysis to practical applications such as price and consumption forecasting. In this work, we address the problem of finding a pooled regression formula relating the monthly figures of price and consumption volumes for each state of the United States during the last twenty years. The model thus obtained is used as the basis for the development of two methods aimed at classifying the states into groups sharing a similar price/consumption relationship: a dendrogram application, and an heuristic algorithm. The details and further applications of these grouping techniques are discussed, along with the ultimate purpose of using this pooled regression model to validate data employed in the stochastic optimization problem studied by the authors.

  3. Text string detection from natural scenes by structure-based partition and grouping.

    Science.gov (United States)

    Yi, Chucai; Tian, YingLi

    2011-09-01

    Text information in natural scene images serves as important clues for many image-based applications such as scene understanding, content-based image retrieval, assistive navigation, and automatic geocoding. However, locating text from a complex background with multiple colors is a challenging task. In this paper, we explore a new framework to detect text strings with arbitrary orientations in complex natural scene images. Our proposed framework of text string detection consists of two steps: 1) image partition to find text character candidates based on local gradient features and color uniformity of character components and 2) character candidate grouping to detect text strings based on joint structural features of text characters in each text string such as character size differences, distances between neighboring characters, and character alignment. By assuming that a text string has at least three characters, we propose two algorithms of text string detection: 1) adjacent character grouping method and 2) text line grouping method. The adjacent character grouping method calculates the sibling groups of each character candidate as string segments and then merges the intersecting sibling groups into text string. The text line grouping method performs Hough transform to fit text line among the centroids of text candidates. Each fitted text line describes the orientation of a potential text string. The detected text string is presented by a rectangle region covering all characters whose centroids are cascaded in its text line. To improve efficiency and accuracy, our algorithms are carried out in multi-scales. The proposed methods outperform the state-of-the-art results on the public Robust Reading Dataset, which contains text only in horizontal orientation. Furthermore, the effectiveness of our methods to detect text strings with arbitrary orientations is evaluated on the Oriented Scene Text Dataset collected by ourselves containing text strings in nonhorizontal

  4. Bacterioplankton responses to iron enrichment during the SAGE experiment

    Science.gov (United States)

    Kuparinen, J.; Hall, J.; Ellwood, M.; Safi, K.; Peloquin, J.; Katz, D.

    2011-03-01

    We studied the microbial food web in the upper 100 m of the water column in iron-limited sub-Antarctic HNLC waters south-east of New Zealand in the SAGE experiment in 2004, with focus on bacterioplankton. Samples were collected daily from inside and outside the iron enriched patch. Short term enrichment experiments were conducted on board in 4 L polycarbonate bottles with water outside the iron enriched patch to study single and combined effects of micronutrient additions on microbial food web. Low bacterial growth was recorded in the study area with community turnover times of 50 h or more during the study period. Measurements of bacterial standing stocks and production rates in the study show minor responses to the large scale iron enrichment, with increase in rates and stocks after the first enrichment and at the end of the study period after the third iron enrichment when solar radiation increased and wind mixing decreased. The average daily bacterial production rates were 31.5 and 33.7 mgCm -2 d -1 for the OUT and IN stations, respectively; thus overall there was not a significant difference between the control and the iron-enriched patch. In the bottle experiments bacterial thymidine incorporation showed responses to single iron and silicic acid enrichments and a major growth response to the combined iron and sucrose enrichments. Phytoplankton chlorophyll- a showed clear stimulation by single additions of iron and silicic acid and silicic acid enhanced the iron impact. Cobalt additions had no effect on bacteria growth and a negative effect on phytoplankton growth. Low bacterial in situ growth rates and the enrichment experiments suggest that bacteria are co-limited by iron and carbon, and that bacterial iron uptake is dependent on carbon supply by the food web. With the high iron quota (μmol Fe mol C -1) bacteria may scavenge considerable amounts of the excess iron, and thus influence the relative importance of the microbial food web as a carbon sink.

  5. Fourth natural analogue working group meeting and Pocos de Caldas project final workshop

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.A.

    1991-01-01

    The fourth meeting of the CEC-sponsored natural analogue working group (NAWG) was held in Pitlochry, Scotland, from 18 to 22 June 1990, and also included the final workshop of the Pocos de Caldas (Brazil) natural analogue project, sponsored by Nagra (CH), SKB (S) UK-DOE and US-DOE. About 80 specialists attended this meeting, originating from EC Member States and also Australia, Brazil, Canada, Finland, Japan, Sweden, Switzerland and the USA. The IAEA and OCDE-NEA were also represented. This plenary meeting was the opportunity to review and discuss five years of progress and activities of natural analogues in central areas of performance assessment: waste forms and engineered barriers, geochemistry and radionuclide speciation, radionuclide migration and the overall geological context of radwaste disposal. In addition, a feedback session provided the opportunity for regulators and those individuals who had advisory roles to give their views and impressions on the significance of natural analogue research. These proceedings, divided into two sessions, contain 32 technical papers and 14 abstracts of published papers

  6. Social Cognitive Maps. A method for identifying social groups in natural settings

    Directory of Open Access Journals (Sweden)

    Francisco Juan Garcia Bacete

    2013-04-01

    Full Text Available This article describes the composite Social-Cognitive Map (SCM, a user-friendly method to identify groups of persons in natural settings. The method is introduced, with its foundations, the interview procedure, the use of SCM software 4.0, and the analysis of the information it yields. Despite having a large tradition, this software is quite unknown in Spanish speaking contexts. This method can be applied in various fields, but in this study we focus on the school context, the classroom and the student groups in the classroom. The SCM provides information on: a the identity of individuals who are members of a peer group and the people with whom each individual is more closely affiliated; b the number of peer groups and the centrality of each group within the social network (class; and c the centrality of each individual in the classroom. Finally, the results obtained in studies which applied this method are commented, and information about its validity, reliability and generalization is provided.

  7. The role of isomorphous substitutions in natural selenides belonging to the pyrite group

    Energy Technology Data Exchange (ETDEWEB)

    Bindi, Luca [Museo di Storia Naturale, sez. di Mineralogia e Litologia, Universita degli Studi di Firenze, via La Pira 4, I-50121 Firenze (Italy)], E-mail: luca.bindi@unifi.it; Cipriani, Curzio [Museo di Storia Naturale, sez. di Mineralogia e Litologia, Universita degli Studi di Firenze, via La Pira 4, I-50121 Firenze (Italy); Pratesi, Giovanni [Museo di Storia Naturale, sez. di Mineralogia e Litologia, Universita degli Studi di Firenze, via La Pira 4, I-50121 Firenze (Italy); Dipartimento di Scienze della Terra, Universita degli Studi di Firenze, via La Pira 4, I-50121 Firenze (Italy); Trosti-Ferroni, Renza [Dipartimento di Scienze della Terra, Universita degli Studi di Firenze, via La Pira 4, I-50121 Firenze (Italy)

    2008-07-14

    The present paper reports chemical and structural data of selenide minerals belonging to the pyrite group. Eighteen samples of minerals in this group with variable chemical composition (7 samples of penroseite, NiSe{sub 2}; 10 samples of krutaite, CuSe{sub 2}; 1 sample of trogtalite, CoSe{sub 2}) were studied by means of X-ray single-crystal diffraction and electron microprobe. On the basis of information gained from the chemical characterization, we can conclude that a complete solid solution between NiSe{sub 2} and CuSe{sub 2} exists in nature with the absence of pure end-members. Although verified only for the Ni-rich members, we also infer a solid solution between NiSe{sub 2} and CoSe{sub 2}. The unit-cell parameters were modeled using a multiple regression method as a function of the Co, Ni, and Cu contents.

  8. Regulation of bacterioplankton density and biomass in tropical shallow coastal lagoons

    Directory of Open Access Journals (Sweden)

    Fabiana MacCord

    Full Text Available AIM: Estimating bacterioplankton density and biomass and their regulating factors is important in order to evaluate aquatic systems' carrying capacity, regarding bacterial growth and the stock of matter in the bacterial community, which can be consumed by higher trophic levels. We aim to evaluate the limnological factors which regulate - in space and time - the bacterioplankton dynamics (abundance and biomass in five tropical coastal lagoons in the state of Rio de Janeiro, Brazil. METHOD: The current study was carried out at the following lagoons: Imboassica, Cabiúnas, Comprida, Carapebus and Garças. They differ in morphology and in their main limnological factors. The limnological variables as well as bacterioplankton abundance and biomass were monthly sampled for 14 months. Model selection analyses were performed in order to evaluate the main variables regulating the bacterioplankton's dynamics in these lagoons. RESULT: The salt concentration and the "space" factor (i.e. different lagoons explained great part of the bacterial density and biomass variance in the studied tropical coastal lagoons. When the lagoons were analyzed separately, salinity still explained great part of the variation of bacterial density and biomass in the Imboassica and Garças lagoons. On the other hand, phosphorus concentration was the main factor explaining the variance of bacterial density and biomass in the distrophic Cabiúnas, Comprida and Carapebus lagoons. There was a strong correlation between bacterial density and biomass (r² = 0.70, p < 0.05, indicating that bacterial biomass variations are highly dependent on bacterial density variations. CONCLUSION: (i Different limnological variables regulate the bacterial density and biomass in the studied coastal lagoons, (ii salt and phosphorus concentrations greatly explained the variation of bacterial density and biomass in the saline and distrophic lagoons, respectively, and (iii N-nitrate and chlorophyll

  9. Basin-scale seasonal changes in marine free-living bacterioplankton community in the Ofunato Bay

    KAUST Repository

    Reza, Md. Shaheed

    2018-04-26

    The Ofunato Bay in the northeastern Pacific Ocean area of Japan possesses the highest biodiversity of marine organisms in the world and has attracted much attention due to its economic and environmental importance. We report here a shotgun metagenomic analysis of the year-round variation in free-living bacterioplankton collected across the entire length of the bay. Phylogenetic differences among spring, summer, autumn and winter bacterioplankton suggested that members of Proteobacteria tended to decrease at high water temperatures and increase at low temperatures. It was revealed that Candidatus Pelagibacter varied seasonally, reaching as much as 60% of all sequences at the genus level in the surface waters during winter. This increase was more evident in the deeper waters, where they reached up to 75%. The relative abundance of Planktomarina also rose during winter and fell during summer. A significant component of the winter bacterioplankton community was Archaea (mainly represented by Nitrosopumilus), as their relative abundance was very low during spring and summer but high during winter. In contrast, Actinobacteria and Cyanobacteria appeared to be higher in abundance during high-temperature periods. It was also revealed that Bacteroidetes constituted a significant component of the summer bacterioplankton community, being the second largest bacterial phylum detected in the Ofunato Bay. Its members, notably Polaribacter and Flavobacterium, were found to be high in abundance during spring and summer, particularly in the surface waters. Principal component analysis and hierarchal clustering analyses showed that the bacterial communities in the Ofunato Bay changed seasonally, likely caused by the levels of organic matter, which would be deeply mixed with surface runoff in the winter.

  10. Combined Carbohydrates Support Rich Communities of Particle-Associated Marine Bacterioplankton.

    Science.gov (United States)

    Sperling, Martin; Piontek, Judith; Engel, Anja; Wiltshire, Karen H; Niggemann, Jutta; Gerdts, Gunnar; Wichels, Antje

    2017-01-01

    Carbohydrates represent an important fraction of labile and semi-labile marine organic matter that is mainly comprised of exopolymeric substances derived from phytoplankton exudation and decay. This study investigates the composition of total combined carbohydrates (tCCHO; >1 kDa) and the community development of free-living (0.2-3 μm) and particle-associated (PA) (3-10 μm) bacterioplankton during a spring phytoplankton bloom in the southern North Sea. Furthermore, rates were determined for the extracellular enzymatic hydrolysis that catalyzes the initial step in bacterial organic matter remineralization. Concentrations of tCCHO greatly increased during bloom development, while the composition showed only minor changes over time. The combined concentration of glucose, galactose, fucose, rhamnose, galactosamine, glucosamine, and glucuronic acid in tCCHO was a significant factor shaping the community composition of the PA bacteria. The richness of PA bacteria greatly increased in the post-bloom phase. At the same time, the increase in extracellular β-glucosidase activity was sufficient to explain the observed decrease in tCCHO, indicating the efficient utilization of carbohydrates by the bacterioplankton community during the post-bloom phase. Our results suggest that carbohydrate concentration and composition are important factors in the multifactorial environmental control of bacterioplankton succession and the enzymatic hydrolysis of organic matter during phytoplankton blooms.

  11. Identification of polyamine-responsive bacterioplankton taxa in South Atlantic Bight.

    Science.gov (United States)

    Lu, Xinxin; Sun, Shulei; Hollibaugh, James T; Mou, Xiaozhen

    2015-12-01

    Putrescine and spermidine are short-chained aliphatic polyamines (PAs) that are ubiquitously distributed in seawater. These compounds may be important sources of dissolved organic carbon and nitrogen for marine bacterioplankton. Here, we used pyrotag sequencing to quantify the response of bacterioplankton to putrescine and spermidine amendments in microcosms established using surface waters collected at various stations in the South Atlantic Bight in October 2011. Our analysis showed that PA-responsive bacterioplankton consisted of bacterial taxa that are typically dominant in marine systems. Rhodobacteraceae (Alphaproteobacteria) was the taxon most responsive to PA additions at the nearshore site. Gammaproteobacteria of the families Piscirickettsiaceae; Vibrionaceae; and Vibrionaceae and Pseudoalteromonadaceae, were the dominant PA-responsive taxa in samples from the river-influenced coastal station, offshore station and open ocean station, respectively. The spatial variability of PA-responsive taxa may be attributed to differences in composition of the initial bacterial community and variations of in situ physiochemical conditions among sites. Our results also provided the first empirical evidence that Gammaproteobacteria might play an important role in PA transformation in marine systems. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. Bacterioplankton community shifts associated with epipelagic and mesopelagic waters in the Southern Ocean.

    Science.gov (United States)

    Yu, Zheng; Yang, Jun; Liu, Lemian; Zhang, Wenjing; Amalfitano, Stefano

    2015-08-10

    The Southern Ocean is among the least explored marine environments on Earth, and still little is known about regional and vertical variability in the diversity of Antarctic marine prokaryotes. In this study, the bacterioplankton community in both epipelagic and mesopelagic waters was assessed at two adjacent stations by high-throughput sequencing and quantitative PCR. Water temperature was significantly higher in the superficial photic zone, while higher salinity and dissolved oxygen were recorded in the deeper water layers. The highest abundance of the bacterioplankton was found at a depth of 75 m, corresponding to the deep chlorophyll maximum layer. Both Alphaproteobacteria and Gammaproteobacteria were the most abundant taxa throughout the water column, while more sequences affiliated to Cyanobacteria and unclassified bacteria were identified from surface and the deepest waters, respectively. Temperature was the most significant environmental variable affecting the bacterial community structure. The bacterial community composition displayed significant differences at the epipelagic layers between two stations, whereas those in the mesopelagic waters were more similar to each other. Our results indicated that the epipelagic bacterioplankton might be dominated by short-term environmental variable conditions, whereas the mesopelagic communities appeared to be structured by longer water-mass residence time and relative stable environmental factors.

  13. Spatially uniform but temporally variable bacterioplankton in a semi-enclosed coastal area.

    Science.gov (United States)

    Meziti, Alexandra; Kormas, Konstantinos A; Moustaka-Gouni, Maria; Karayanni, Hera

    2015-07-01

    Studies focusing on the temporal and spatial dynamics of bacterioplankton communities within littoral areas undergoing direct influences from the coast are quite limited. In addition, they are more complicated to resolve compared to communities in the open ocean. In order to elucidate the effects of spatial vs. temporal variability on bacterial communities in a highly land-influenced semi-enclosed gulf, surface bacterioplankton communities from five coastal sites in Igoumenitsa Gulf (Ionian Sea, Greece) were analyzed over a nine-month period using 16S rDNA 454-pyrosequencing. Temporal differences were more pronounced than spatial ones, with lower diversity indices observed during the summer months. During winter and early spring, bacterial communities were dominated by SAR11 representatives, while this pattern changed in May when they were abruptly replaced by members of Flavobacteriales, Pseudomonadales, and Alteromonadales. Additionally, correlation analysis showed high negative correlations between the presence of SAR11 OTUs in relation to temperature and sunlight that might have driven, directly or indirectly, the disappearance of these OTUs in the summer months. The dominance of SAR11 during the winter months further supported the global distribution of the clade, not only in the open-sea, but also in coastal systems. This study revealed that specific bacteria exhibited distinct succession patterns in an anthropogenic-impacted coastal system. The major bacterioplankton component was represented by commonly found marine bacteria exhibiting seasonal dynamics, while freshwater and terrestrial-related phylotypes were absent. Copyright © 2015 Elsevier GmbH. All rights reserved.

  14. Seasonal assemblages and short-lived blooms in coastal north-west Atlantic Ocean bacterioplankton.

    Science.gov (United States)

    El-Swais, Heba; Dunn, Katherine A; Bielawski, Joseph P; Li, William K W; Walsh, David A

    2015-10-01

    Temperate oceans are inhabited by diverse and temporally dynamic bacterioplankton communities. However, the role of the environment, resources and phytoplankton dynamics in shaping marine bacterioplankton communities at different time scales remains poorly constrained. Here, we combined time series observations (time scales of weeks to years) with molecular analysis of formalin-fixed samples from a coastal inlet of the north-west Atlantic Ocean to show that a combination of temperature, nitrate, small phytoplankton and Synechococcus abundances are best predictors for annual bacterioplankton community variability, explaining 38% of the variation. Using Bayesian mixed modelling, we identified assemblages of co-occurring bacteria associated with different seasonal periods, including the spring bloom (e.g. Polaribacter, Ulvibacter, Alteromonadales and ARCTIC96B-16) and the autumn bloom (e.g. OM42, OM25, OM38 and Arctic96A-1 clades of Alphaproteobacteria, and SAR86, OM60 and SAR92 clades of Gammaproteobacteria). Community variability over spring bloom development was best explained by silicate (32%)--an indication of rapid succession of bacterial taxa in response to diatom biomass--while nanophytoplankton as well as picophytoplankton abundance explained community variability (16-27%) over the transition into and out of the autumn bloom. Moreover, the seasonal structure was punctuated with short-lived blooms of rare bacteria including the KSA-1 clade of Sphingobacteria related to aromatic hydrocarbon-degrading bacteria. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Understanding diversity patterns in bacterioplankton communities from a sub-Antarctic peatland.

    Science.gov (United States)

    Quiroga, María Victoria; Valverde, Angel; Mataloni, Gabriela; Cowan, Don

    2015-06-01

    Bacterioplankton communities inhabiting peatlands have the potential to influence local ecosystem functions. However, most microbial ecology research in such wetlands has been done in ecosystems (mostly peat soils) of the Northern Hemisphere, and very little is known of the factors that drive bacterial community assembly in other regions of the world. In this study, we used high-throughput sequencing to analyse the structure of the bacterial communities in five pools located in a sub-Antarctic peat bog (Tierra del Fuego, Argentina), and tested for relationships between bacterial communities and environmental conditions. Bacterioplankton communities in peat bog pools were diverse and dominated by members of the Proteobacteria, Actinobacteria, Bacteroidetes and Verrucomicrobia. Community structure was largely explained by differences in hydrological connectivity, pH and nutrient status (ombrotrophic versus minerotrophic pools). Bacterioplankton communities in ombrotrophic pools showed phylogenetic clustering, suggesting a dominant role of deterministic processes in shaping these assemblages. These correlations between habitat characteristics and bacterial diversity patterns provide new insights into the factors regulating microbial populations in peatland ecosystems. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  16. Marine bacterioplankton community turnover within seasonally hypoxic waters of a subtropical sound: Devil's Hole, Bermuda.

    Science.gov (United States)

    Parsons, Rachel J; Nelson, Craig E; Carlson, Craig A; Denman, Carmen C; Andersson, Andreas J; Kledzik, Andrew L; Vergin, Kevin L; McNally, Sean P; Treusch, Alexander H; Giovannoni, Stephen J

    2015-10-01

    Understanding bacterioplankton community dynamics in coastal hypoxic environments is relevant to global biogeochemistry because coastal hypoxia is increasing worldwide. The temporal dynamics of bacterioplankton communities were analysed throughout the illuminated water column of Devil's Hole, Bermuda during the 6-week annual transition from a strongly stratified water column with suboxic and high-pCO2 bottom waters to a fully mixed and ventilated state during 2008. A suite of culture-independent methods provided a quantitative spatiotemporal characterization of bacterioplankton community changes, including both direct counts and rRNA gene sequencing. During stratification, the surface waters were dominated by the SAR11 clade of Alphaproteobacteria and the cyanobacterium Synechococcus. In the suboxic bottom waters, cells from the order Chlorobiales prevailed, with gene sequences indicating members of the genera Chlorobium and Prosthecochloris--anoxygenic photoautotrophs that utilize sulfide as a source of electrons for photosynthesis. Transitional zones of hypoxia also exhibited elevated levels of methane- and sulfur-oxidizing bacteria relative to the overlying waters. The abundance of both Thaumarcheota and Euryarcheota were elevated in the suboxic bottom waters (> 10(9) cells l(-1)). Following convective mixing, the entire water column returned to a community typical of oxygenated waters, with Euryarcheota only averaging 5% of cells, and Chlorobiales and Thaumarcheota absent. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  17. Spatial abundance and diversity of bacterioplankton in a typical stream-forming ecosystem, Huangqian Reservoir, China.

    Science.gov (United States)

    Wei, Guangshan; Li, Jing; Wang, Ningxin; Gao, Zheng

    2014-10-01

    The specific freshwater environment of reservoirs formed by streams has not been well studied. In this paper, the bacterioplankton community in such a reservoir, the Huangqian Reservoir in eastern China, was described using culture-independent molecular methods. We found that the most dominant bacterioplankton were affiliated with Cyanobacteria, followed by Betaproteobacteria, Bacteroidetes, Gammaproteobacteria, and Actinobacteria. Both bacterial abundance and diversity increased along the direction of water flow, and the 16S rRNA gene copy number in the water outlet was nearly an order of magnitude higher than that in the water inlet. Pearson correlation analyses indicated that nitrate had a significantly negative correlation with the bacterial abundance (p bacterioplankton. According to redundancy analysis, nitrate and dissolved oxygen were the major factors influencing the bacterial communities. In addition, we attempted to determine the reasons why such a reservoir could maintain good ecological balance for a period of decades, and we found that the environmental factors and bacterial communities both played critical roles. This research will benefit our understanding of bacterial communities and their surrounding environments in freshwater ecosystems.

  18. Biosynthesis of gold and silver nanoparticles by natural precursor clove and their functionalization with amine group

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ashwani Kumar; Talat, Mahe [Banaras Hindu University, Nanoscience and Nanotechnology Unit, Department of Physics (India); Singh, D. P. [Southern Illinois University Carbondale, Department of Physics (United States); Srivastava, O. N., E-mail: hepons@yahoo.co [Banaras Hindu University, Nanoscience and Nanotechnology Unit, Department of Physics (India)

    2010-06-15

    We report a simple and cost effective way for synthesis of metallic nanoparticles (Au and Ag) using natural precursor clove. Au and Ag nanoparticles have been synthesized by reducing the aqueous solution of AuCl{sub 4} and AgNO{sub 3} with clove extract. One interesting aspect here is that reduction time is quite small (few minutes instead of hours as compared to other natural precursors). We synthesized gold and silver nanoparticles of different shape and size by varying the ratio of AuCl{sub 4} and AgNO{sub 3} with respect to clove extract, where the dominant component is eugenol. The evolution of Au and Ag nanoparticles from the reduction of different ratios of AuCl{sub 4} and AgNO{sub 3} with optimised concentration of the clove extract has been evaluated through monitoring of surface plasmon behaviour as a function of time. The reduction of AuCl{sub 4} and AgNO{sub 3} by eugenol is because of the inductive effect of methoxy and allyl groups which are present at ortho and para positions of proton releasing -OH group as two electrons are released from one molecule of eugenol. This is followed by the formation of resonating structure of the anionic form of eugenol. The presence of methoxy and allyl groups has been confirmed by FTIR. To the best of our knowledge, use of clove as reducing agent, the consequent very short time (minutes instead of hours and without any scavenger) and the elucidation of mechanism of reduction based on FTIR analysis has not been attempted earlier.

  19. Responses of spatial-temporal dynamics of bacterioplankton community to large-scale reservoir operation: a case study in the Three Gorges Reservoir, China.

    Science.gov (United States)

    Li, Zhe; Lu, Lunhui; Guo, Jinsong; Yang, Jixiang; Zhang, Jiachao; He, Bin; Xu, Linlin

    2017-02-13

    Large rivers are commonly regulated by damming, yet the effects of such disruption on bacterioplankton community structures have not been adequately studied. The aim of this study was to explore the biogeographical patterns present under dam regulation and to uncover the major drivers structuring bacterioplankton communities. Bacterioplankton assemblages in the Three Gorges Reservoir (TGR) were analyzed using Illumina Miseq sequencing by comparing seven sites located within the TGR before and after impoundment. This approach revealed ecological and spatial-temporal variations in bacterioplankton community composition along the longitudinal axis. The community was dynamic and dominated by Proteobacteria and Actinobacteria phyla, encompassing 39.26% and 37.14% of all sequences, respectively, followed by Bacteroidetes (8.67%) and Cyanobacteria (3.90%). The Shannon-Wiener index of the bacterioplankton community in the flood season (August) was generally higher than that in the impoundment season (November). Principal Component Analysis of the bacterioplankton community compositions showed separation between different seasons and sampling sites. Results of the relationship between bacterioplankton community compositions and environmental variables highlighted that ecological processes of element cycling and large dam disturbances are of prime importance in driving the assemblages of riverine bacterioplankton communities.

  20. A Global eDNA Comparison of Freshwater Bacterioplankton Assemblages Focusing on Large-River Floodplain Lakes of Brazil.

    Science.gov (United States)

    Tessler, Michael; Brugler, Mercer R; DeSalle, Rob; Hersch, Rebecca; Velho, Luiz Felipe M; Segovia, Bianca T; Lansac-Toha, Fabio A; Lemke, Michael J

    2017-01-01

    With its network of lotic and lentic habitats that shift during changes in seasonal connection, the tropical and subtropical large-river systems represent possibly the most dynamic of all aquatic environments. Pelagic water samples were collected from Brazilian floodplain lakes (total n = 58) in four flood-pulsed systems (Amazon [n = 21], Araguaia [n = 14], Paraná [n = 15], and Pantanal [n = 8]) in 2011-2012 and sequenced via 454 for bacterial environmental DNA using 16S amplicons; additional abiotic field and laboratory measurements were collected for the assayed lakes. We report here a global comparison of the bacterioplankton makeup of freshwater systems, focusing on a comparison of Brazilian lakes with similar freshwater systems across the globe. The results indicate a surprising similarity at higher taxonomic levels of the bacterioplankton in Brazilian freshwater with global sites. However, substantial novel diversity at the family level was also observed for the Brazilian freshwater systems. Brazilian freshwater bacterioplankton richness was relatively average globally. Ordination results indicate that Brazilian bacterioplankton composition is unique from other areas of the globe. Using Brazil-only ordinations, floodplain system differentiation most strongly correlated with dissolved oxygen, pH, and phosphate. Our data on Brazilian freshwater systems in combination with analysis of a collection of freshwater environmental samples from across the globe offers the first regional picture of bacterioplankton diversity in these important freshwater systems.

  1. Warming and nutrient enrichment in combination increase stochasticity and beta diversity of bacterioplankton assemblages across freshwater mesocosms.

    Science.gov (United States)

    Ren, Lijuan; He, Dan; Chen, Zhen; Jeppesen, Erik; Lauridsen, Torben L; Søndergaard, Martin; Liu, Zhengwen; Wu, Qinglong L

    2017-03-01

    The current climate warming and eutrophication are known to interactively threaten freshwater biodiversity; however, the interactive effects on lacustrine bacterioplankton diversity remain to be determined. Here, we analyzed the spring bacterioplankton community composition (BCC) in 24 outdoor, flow-through mesocosms (mimicking shallow lake environments) under 3 temperature scenarios and 2 nutrient regimes. Our results revealed that neither long-term warming (8.5 years) nor nutrient enrichment had significant effects on bacterioplankton alpha diversity, whereas long-term enhanced warming (elevated 50% above the IPCC A2 climate scenario) and nutrient enrichment in combination increased bacterioplankton beta diversity. We also found that BCC shifted significantly under enhanced warming and nutrient-enriched conditions towards decreased relative abundances of Actinobacteria, Bacteroidetes and Betaproteobacteria, whereas the percentages of Cyanobacteria, total rare phyla and unclassified phyla significantly increased. Null-model tests indicated that deterministic processes played a more important role than stochastic processes in determining BCC. However, the relative importance of stochasticity, primarily ecological drift, was enhanced and contributed to the increased beta diversity of BCC under enhanced warming and nutrient-enriched conditions. Overall, our study suggests that the synergetic effects of warming and nutrient enrichment may result in high variability in the composition of bacterioplankton communities in lacustrine water bodies.

  2. Glutathione-Conjugates of Deoxynivalenol in Naturally Contaminated Grain Are Primarily Linked via the Epoxide Group

    Science.gov (United States)

    Uhlig, Silvio; Stanic, Ana; Hofgaard, Ingerd S.; Kluger, Bernhard; Schuhmacher, Rainer; Miles, Christopher O.

    2016-01-01

    A glutathione (GSH) adduct of the mycotoxin 4-deoxynivalenol (DON), together with a range of related conjugates, has recently been tentatively identified by LC-MS of DON-treated wheat spikelets. In this study, we prepared samples of DON conjugated at the 10- and 13-positions with GSH, Cys, CysGly, γ-GluCys and N-acetylcysteine (NAC). The mixtures of conjugates were used as standards for LC-HRMS analysis of one of the DON-treated wheat spikelet samples, as well as 19 Norwegian grain samples of spring wheat and 16 grain samples of oats that were naturally-contaminated with DON at concentrations higher than 1 mg/kg. The artificially-contaminated wheat spikelets contained conjugates of GSH, CysGly and Cys coupled at the olefinic 10-position of DON, whereas the naturally-contaminated harvest-ripe grain samples contained GSH, CysGly, Cys, and NAC coupled mainly at the 13-position on the epoxy group. The identities of the conjugates were confirmed by LC-HRMS comparison with authentic standards, oxidation to the sulfoxides with hydrogen peroxide, and examination of product-ion spectra from LC-HRMS/MS analysis. No γ-GluCys adducts of DON were detected in any of the samples. The presence of 15-O-acetyl-DON was demonstrated for the first time in Norwegian grain. The results indicate that a small but significant proportion of DON is metabolized via the GSH-conjugation pathway in plants. To our knowledge, this is the first report of in vivo conjugation of trichothecenes via their epoxy group, which has generally been viewed as unreactive. Because conjugation at the 13-position of DON and other trichothecenes has been shown to be irreversible, this type of conjugate may prove useful as a biomarker of exposure to DON and other 12,13-epoxytrichothecenes. PMID:27845722

  3. Glutathione-Conjugates of Deoxynivalenol in Naturally Contaminated Grain Are Primarily Linked via the Epoxide Group

    Directory of Open Access Journals (Sweden)

    Silvio Uhlig

    2016-11-01

    Full Text Available A glutathione (GSH adduct of the mycotoxin 4-deoxynivalenol (DON, together with a range of related conjugates, has recently been tentatively identified by LC-MS of DON-treated wheat spikelets. In this study, we prepared samples of DON conjugated at the 10- and 13-positions with GSH, Cys, CysGly, γ-GluCys and N-acetylcysteine (NAC. The mixtures of conjugates were used as standards for LC-HRMS analysis of one of the DON-treated wheat spikelet samples, as well as 19 Norwegian grain samples of spring wheat and 16 grain samples of oats that were naturally-contaminated with DON at concentrations higher than 1 mg/kg. The artificially-contaminated wheat spikelets contained conjugates of GSH, CysGly and Cys coupled at the olefinic 10-position of DON, whereas the naturally-contaminated harvest-ripe grain samples contained GSH, CysGly, Cys, and NAC coupled mainly at the 13-position on the epoxy group. The identities of the conjugates were confirmed by LC-HRMS comparison with authentic standards, oxidation to the sulfoxides with hydrogen peroxide, and examination of product-ion spectra from LC-HRMS/MS analysis. No γ-GluCys adducts of DON were detected in any of the samples. The presence of 15-O-acetyl-DON was demonstrated for the first time in Norwegian grain. The results indicate that a small but significant proportion of DON is metabolized via the GSH-conjugation pathway in plants. To our knowledge, this is the first report of in vivo conjugation of trichothecenes via their epoxy group, which has generally been viewed as unreactive. Because conjugation at the 13-position of DON and other trichothecenes has been shown to be irreversible, this type of conjugate may prove useful as a biomarker of exposure to DON and other 12,13-epoxytrichothecenes.

  4. Bacterioplankton Responses to Increased Organic Carbon and Nutrient Loading in a Boreal Estuary-Separate and Interactive Effects on Growth and Respiration.

    Science.gov (United States)

    Soares, Ana R A; Kritzberg, Emma S; Custelcean, Ioana; Berggren, Martin

    2017-12-18

    Increases in the terrestrial export of dissolved organic carbon (C) to rivers may be associated with additional loading of organic nitrogen (N) and phosphorus (P) to the coastal zone. However, little is known about how these resources interact in the regulation of heterotrophic bacterioplankton metabolism in boreal coastal ecosystems. Here, we measured changes in bacterioplankton production (BP) and respiration (BR) in response to full-factorial (C, N, and P) enrichment experiments at two sites within the Öre estuary, northern Sweden. The BR was stimulated by single C additions and further enhanced by combined additions of C and other nutrients. Single addition of N or P had no effect on BR rates. In contrast, BP was primarily limited by P at the site close to the river mouth and did not respond to C or N additions. However, at the site further away from the near the river mouth, BP was slightly stimulated by single additions of C. Possibly, the natural inflow of riverine bioavailable dissolved organic carbon induced local P limitation of BP near the river mouth, which was then exhausted and resulted in C-limited BP further away from the river mouth. We observed positive interactions between all elements on all responses except for BP at the site close to the river mouth, where P showed an independent effect. In light of predicted increases in terrestrial P and C deliveries, we expect future increases in BP and increases of BR of terrestrially delivered C substrates at the Öre estuary and similar areas.

  5. Are oceanic fronts ecotones? Seasonal changes along the subtropical front show fronts as bacterioplankton transition zones but not diversity hotspots.

    Science.gov (United States)

    Morales, Sergio E; Meyer, Moana; Currie, Kim; Baltar, Federico

    2018-04-01

    Ecotones are regarded as diversity hotspots in terrestrial systems, but it is unknown if this 'ecotone effect' occurs in the marine environment. Oceanic fronts are widespread mesoscale features, present in the boundary between different water masses, and are arguably the best potential examples of ecotones in the ocean. Here we performed the first seasonal study along an oceanic front, combining 16S rRNA gene sequencing coupled with a high spatial resolution analysis of the physical properties of the water masses. Using the Subtropical Frontal Zone off New Zealand we demonstrate that fronts delimit shifts in bacterioplankton community composition between water masses, but that the strength of this effect is seasonally dependent. While creating a transition zone where physicochemical parameters and bacterioplankton communities get mixed, this ecotone does not result in increased diversity. Thus unlike terrestrial ecotones, oceanic fronts are boundaries but not hotspots of bacterioplankton diversity in the ocean. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Spatial and seasonal distributions of bacterioplankton in the Pearl River Estuary: The combined effects of riverine inputs, temperature, and phytoplankton.

    Science.gov (United States)

    Li, Jiajun; Jiang, Xin; Jing, Zhiyou; Li, Gang; Chen, Zuozhi; Zhou, Linbin; Zhao, Chunyu; Liu, Jiaxing; Tan, Yehui

    2017-12-15

    In this study, we used flow cytometry and 16S rRNA gene pyrosequencing to investigate bacterioplankton (heterotrophic bacteria and picocyanobacteria) abundance and community structure in surface waters along the Pearl River Estuary. The results showed significant differences in bacterioplankton dynamics between fresh- and saltwater sites and between wet and dry season. Synechococcus constituted the majority of picocyanobacteria in both seasons. During the wet season, Synechococcus reached extremely high abundance at the mouth of the estuary, and heterotrophic bacteria were highly abundant (>10 6 cellsml -1 ) throughout the studied region. At the same time, bacterioplankton decreased dramatically during the dry season. Pyrosequencing data indicated that salinity was a key parameter in shaping microbial community structure during both seasons. Phytoplankton was also an important factor; the proportion of Synechococcus and Rhodobacteriales was elevated at the frontal zone with higher chlorophyll a during the wet season, whereas Synechococcus were markedly reduced during the dry season. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Walking for Well-Being: Are Group Walks in Certain Types of Natural Environments Better for Well-Being than Group Walks in Urban Environments?

    Directory of Open Access Journals (Sweden)

    Sara L. Warber

    2013-10-01

    Full Text Available The benefits of walking in natural environments for well-being are increasingly understood. However, less well known are the impacts different types of natural environments have on psychological and emotional well-being. This cross-sectional study investigated whether group walks in specific types of natural environments were associated with greater psychological and emotional well-being compared to group walks in urban environments. Individuals who frequently attended a walking group once a week or more (n = 708 were surveyed on mental well-being (Warwick Edinburgh Mental Well-being Scale, depression (Major Depressive Inventory, perceived stress (Perceived Stress Scale and emotional well-being (Positive and Negative Affect Schedule. Compared to group walks in urban environments, group walks in farmland were significantly associated with less perceived stress and negative affect, and greater mental well-being. Group walks in green corridors were significantly associated with less perceived stress and negative affect. There were no significant differences between the effect of any environment types on depression or positive affect. Outdoor walking group programs could be endorsed through “green prescriptions” to improve psychological and emotional well-being, as well as physical activity.

  8. Walking for well-being: are group walks in certain types of natural environments better for well-being than group walks in urban environments?

    Science.gov (United States)

    Marselle, Melissa R; Irvine, Katherine N; Warber, Sara L

    2013-10-29

    The benefits of walking in natural environments for well-being are increasingly understood. However, less well known are the impacts different types of natural environments have on psychological and emotional well-being. This cross-sectional study investigated whether group walks in specific types of natural environments were associated with greater psychological and emotional well-being compared to group walks in urban environments. Individuals who frequently attended a walking group once a week or more (n = 708) were surveyed on mental well-being (Warwick Edinburgh Mental Well-being Scale), depression (Major Depressive Inventory), perceived stress (Perceived Stress Scale) and emotional well-being (Positive and Negative Affect Schedule). Compared to group walks in urban environments, group walks in farmland were significantly associated with less perceived stress and negative affect, and greater mental well-being. Group walks in green corridors were significantly associated with less perceived stress and negative affect. There were no significant differences between the effect of any environment types on depression or positive affect. Outdoor walking group programs could be endorsed through "green prescriptions" to improve psychological and emotional well-being, as well as physical activity.

  9. Ingestion of microplastics by natural zooplankton groups in the northern South China Sea.

    Science.gov (United States)

    Sun, Xiaoxia; Li, Qingjie; Zhu, Mingliang; Liang, Junhua; Zheng, Shan; Zhao, Yongfang

    2017-02-15

    The ingestion of microplastics by five natural zooplankton groups in the northern South China Sea was studied for the first time and two types of sampling nets (505μm and 160μm in mesh size) were compared. The microplastics were detected in zooplankton sampled from 16 stations, with the fibrous microplastics accounting for the largest proportion (70%). The main component of the found microplastics was polyester. The average length of the microplastics was 125μm and 167μm for Nets I and II, respectively. The encounter rates of microplastics/zooplankton increased with trophic levels. The average encounter rate of microplastics/zooplankton was 5%, 15%, 34%, 49%, and 120% for Net I, and 8%, 21%, 47%, 60%, and 143% for Net II for copepods, chaetognaths, jellyfish, shrimp, and fish larvae, respectively. The average abundance of microplastics that were ingested by zooplankton was 4.1pieces/m 3 for Net I and 131.5pieces/m 3 for Net II. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Natural variation of HIV-1 group M integrase: Implications for a new class of antiretroviral inhibitors

    Directory of Open Access Journals (Sweden)

    Gifford Robert J

    2008-08-01

    Full Text Available Abstract HIV-1 integrase is the third enzymatic target of antiretroviral (ARV therapy. However, few data have been published on the distribution of naturally occurring amino acid variation in this enzyme. We therefore characterized the distribution of integrase variants among more than 1,800 published group M HIV-1 isolates from more than 1,500 integrase inhibitor (INI-naïve individuals. Polymorphism rates equal or above 0.5% were found for 34% of the central core domain positions, 42% of the C-terminal domain positions, and 50% of the N-terminal domain positions. Among 727 ARV-naïve individuals in whom the complete pol gene was sequenced, integrase displayed significantly decreased inter- and intra-subtype diversity and a lower Shannon's entropy than protease or RT. All primary INI-resistance mutations with the exception of E157Q – which was present in 1.1% of sequences – were nonpolymorphic. Several accessory INI-resistance mutations including L74M, T97A, V151I, G163R, and S230N were also polymorphic with polymorphism rates ranging between 0.5% to 2.0%.

  11. Alteration in successional trajectories of bacterioplankton communities in response to co-exposure of cadmium and phenanthrene in coastal water microcosms.

    Science.gov (United States)

    Qian, Jie; Ding, Qifang; Guo, Annan; Zhang, Demin; Wang, Kai

    2017-02-01

    Coexistence of heavy metals and organic contaminants in coastal ecosystems may lead to complicated circumstances in ecotoxicological assessment for biological communities due to potential interactions of contaminants. Consequences of metals and polycyclic aromatic hydrocarbons (PAHs) co-contamination on coastal marine microbes at the community level were paid less attention. We chose cadmium (Cd) and phenanthrene (PHE) as representatives of metals and PAHs, respectively, and mimicked contaminations using coastal water microcosms spiked with Cd (1 mg/L), PHE (1 mg/L), and their mixture over two weeks. 16S rRNA gene amplicon sequencing was used to compare individual and cumulative effects of Cd and PHE on temporal succession of bacterioplankton communities. Although we found dramatic impacts of dimethylsulfoxide (DMSO, used as a carrier solvent for PHE) on bacterial α-diversity and composition, the individual and cumulative effects of Cd and PHE on bacterial α-diversity were temporally variable showing an antagonistic pattern at early stage in the presence of DMSO. Temporal succession of bacterial community composition (BCC) was associated with temporal variability of water physicochemical parameters, each of which explained more variation in BCC than two target contaminants did. However, Cd, PHE, and their mixture distinctly altered the successional trajectories of BCC, while only the effect of Cd was retained at the end of experiment, suggesting certain resilience in BCC after the complete dissipation of PHE along the temporal trajectory. Moreover, bacterial assemblages at the genus level associated with the target contaminants were highly time-dependent and more unpredictable in the co-contamination group, in which some genera possessing hydrocarbon-degrading members might contribute to PHE degradation. These results provide preliminary insights into how co-exposure of Cd and PHE phylogenetically alters successional trajectories of bacterioplankton communities

  12. Bacterioplankton diversity and community composition in the Southern Lagoon of Venice.

    Science.gov (United States)

    Simonato, Francesca; Gómez-Pereira, Paola R; Fuchs, Bernhard M; Amann, Rudolf

    2010-04-01

    The Lagoon of Venice is a large water basin that exchanges water with the Northern Adriatic Sea through three large inlets. In this study, the 16S rRNA approach was used to investigate the bacterial diversity and community composition within the southern basin of the Lagoon of Venice and at one inlet in October 2007 and June 2008. Comparative sequence analysis of 645 mostly partial 16S rRNA gene sequences indicated high diversity and dominance of Alphaproteobacteria, Gammaproteobacteria and Bacteroidetes at the lagoon as well as at the inlet station, therefore pointing to significant mixing. Many of these sequences were close to the 16S rRNA of marine, often coastal, bacterioplankton, such as the Roseobacter clade, the family Vibrionaceae, and class Flavobacteria. Sequences of Actinobacteria were indicators of a freshwater input. The composition of the bacterioplankton was quantified by catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) with a set of rRNA-targeted oligonucleotide probes. CARD-FISH counts corroborated the dominance of members of the phyla Alphaproteobacteria, Gammaproteobacteria and Bacteroidetes. When assessed by a probe set for the quantification of selected clades within Alphaproteobacteria and Gammaproteobacteria, bacterioplankton composition differed between October 2007 and June 2008, and also between the inlet and the lagoon. In particular, members of the readily culturable copiotrophic gammaproteobacterial genera Vibrio, Alteromonas and Pseudoalteromonas were enriched in the southern basin of the Lagoon of Venice. Interestingly, the alphaproteobacterial SAR11 clade and related clusters were also present in high abundances at the inlet and within the lagoon, which was indicative of inflow of water from the open sea.

  13. Distribution and diversity of bacterioplankton communities in subtropical seawater around Xiamen Island, China.

    Science.gov (United States)

    Shan, Dapeng; Wei, Guangshan; Li, Mingcong; Wang, Wanpeng; Li, Xu; Gao, Zheng; Shao, Zongze

    2015-06-01

    Marine bacterioplankton communities have profound impact on global biogeochemical cycles and ecological balances. However, relatively little is known about the bacterioplankton communities and the factors shaping their spatial distribution in subtropical island. Here, the bacterioplankton communities around a typical subtropical island, Xiamen Island, were revealed by analyzing bacterial 16S rRNA gene through quantitative PCR (qPCR) and 454 pyrosequencing methods. The qPCR results indicated that the abundance of 16S rRNA gene ranged from 2.07 × 10(7) to 2.13 × 10(8)copies mL(-1) in surface seawater among eight sampling sites (S1-S8) around Xiamen Island, and the nitrogen and phosphorus-rich sites (S5 and S8) were detected with higher 16S rRNA gene abundance. Pyrosequencing evidenced that a total of 267 genera of 47 classes in 26 different phyla (or candidate phyla) and some unclassified bacteria were obtained from seawater around Xiamen Island. The most dominant phylum was Proteobacteria (49.62-76.84% among sites), followed by Bacteroidetes (6.64-20.88%), Actinobacteria (2.58-9.20%), Firmicutes (0.03-13.30%), Verrucomicrobia (0.23-2.67%) and Planctomycetes (0.14-2.20%). Among eight sites, the nitrogen and phosphorus-rich sites (S5 and S8) exhibited higher proportions of Gammaproteobacteria, Epsilonproteobacteria, Firmicutes and lower proportions of Alphaproteobacteria and Planctomycetes than other sites. S5 and S8 also had more similar β-diversity, and sampling site near the estuary (S8) showed the highest bacterial diversity. Redundancy analysis (RDA) confirmed that total nitrogen and total phosphorus significantly (Pbacterioplankton communities around Xiamen Island. These results will provide insights into bacterial abundance, diversity and distribution patterns, as well as their controlling factors, in subtropical marine ecosystems. Copyright © 2015 Elsevier GmbH. All rights reserved.

  14. group

    African Journals Online (AJOL)

    Jane T. B, Nlandu M, Matondo M, Evelyn G. L.. Factors Influencing the Use of Traditional versus. Modern Family Planning Methods in Bas Zaire. Studies in Family Planning, November/December. 1885;16(6):332-34l. Peter W. H. A natural method of child spacing. American Journal of Obstetrics and Gynecology,. December ...

  15. Bacterioplankton community composition along a salinity gradient of sixteen high-mountain lakes located on the Tibetan Plateau, China

    NARCIS (Netherlands)

    Wu, Q.L.; Zwart, G.; Schauer, M.; Kamst-van Agterveld, M.P.; Hahn, M.W.

    2006-01-01

    The influence of altitude and salinity on bacterioplankton community composition (BCC) in 16 high-mountain lakes located at altitudes of 2,817 to 5,134 m on the Eastern Qinghai-Xizang (Tibetan) Plateau, China, spanning a salinity gradient from 0.02% (freshwater) to 22.3% (hypersaline), was

  16. .i.Candidatus./i. Planktophila limnetica, an actinobacterium representing one of the most numerically important taxa in freshwater bacterioplankton

    Czech Academy of Sciences Publication Activity Database

    Jezbera, Jan; Sharma, A. K.; Brandt, U.; Doolittle, W.F.; Hahn, M.W.

    2009-01-01

    Roč. 59, č. 11 (2009), s. 2864-2869 ISSN 1466-5026 Institutional research plan: CEZ:AV0Z60170517 Keywords : Actinobacteria * Planktophila * freshwater * bacterioplankton Subject RIV: EE - Microbiology, Virology Impact factor: 2.113, year: 2009

  17. Discordance Between Resident and Active Bacterioplankton in Free-Living and Particle-Associated Communities in Estuary Ecosystem.

    Science.gov (United States)

    Li, Jia-Ling; Salam, Nimaichand; Wang, Pan-Deng; Chen, Lin-Xing; Jiao, Jian-Yu; Li, Xin; Xian, Wen-Dong; Han, Ming-Xian; Fang, Bao-Zhu; Mou, Xiao-Zhen; Li, Wen-Jun

    2018-03-16

    Bacterioplankton are the major driving force for biogeochemical cycles in estuarine ecosystems, but the communities that mediate these processes are largely unexplored. We sampled in the Pearl River Estuary (PRE) to examine potential differences in the taxonomic composition of resident (DNA-based) and active (RNA-based) bacterioplankton communities in free-living and particle-associated fractions. MiSeq sequencing data showed that the overall bacterial diversity in particle-associated fractions was higher than in free-living communities. Further in-depth analyses of the sequences revealed a positive correlation between resident and active bacterioplankton communities for the particle-associated fraction but not in the free-living fraction. However, a large overlapping of OTUs between free-living and particle-associated communities in PRE suggested that the two fractions may be actively exchanged. We also observed that the positive correlation between resident and active communities is more prominent among the abundant OTUs (relative abundance > 0.2%). Further, the results from the present study indicated that low-abundance bacterioplankton make an important contribution towards the metabolic activity in PRE.

  18. Snowmelt-driven changes in dissolved organic matter and bacterioplankton communities in the Heilongjiang watershed of China.

    Science.gov (United States)

    Qiu, Linlin; Cui, Hongyang; Wu, Junqiu; Wang, Baijie; Zhao, Yue; Li, Jiming; Jia, Liming; Wei, Zimin

    2016-06-15

    Bacterioplankton plays a significant role in the circulation of materials and ecosystem function in the biosphere. Dissolved organic matter (DOM) from dead plant material and surface soil leaches into water bodies when snow melts. In our study, water samples from nine sampling sites along the Heilongjiang watershed were collected in February and June 2014 during which period snowmelt occurred. The goal of this study was to characterize changes in DOM and bacterioplankton community composition (BCC) associated with snowmelt, the effects of DOM, environmental and geographical factors on the distribution of BCC and interactions of aquatic bacterioplankton populations with different sources of DOM in the Heilongjiang watershed. BCC was measured by denaturing gradient gel electrophoresis (DGGE). DOM was measured by excitation-emission matrix (EEM) fluorescence spectroscopy. Bacterioplankton exhibited a distinct seasonal change in community composition due to snowmelt at all sampling points except for EG. Redundancy analysis (RDA) indicated that BCC was more closely related to DOM (Components 1 and 4, dissolved organic carbon, biochemical oxygen demand and chlorophyll a) and environmental factors (water temperature and nitrate nitrogen) than geographical factors. Furthermore, DOM had a greater impact on BCC than environmental factors (29.80 vs. 15.90% of the variation). Overall, spring snowmelt played an important role in altering the quality and quantity of DOM and BCC in the Heilongjiang watershed. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Dissolved organic carbon and relationship with bacterioplankton community composition in 3 lake regions of Lake Taihu, China.

    Science.gov (United States)

    Pang, Xinghong; Shen, Hong; Niu, Yuan; Sun, Xiaoxue; Chen, Jun; Xie, Ping

    2014-10-01

    To clarify the relationships between dissolved organic carbon (DOC) and bacterioplankton community composition (BCC), a 1-year survey (June 2009 - May 2010) was conducted in 3 regions of Lake Taihu (Meiliang Bay, Lake Center, and Eastern Taihu), China. Polymerase chain reaction - denaturing gradient gel electrophoresis was used to analyze the composition and heterogeneity of the bacterioplankton community. Canonical correspondence analysis was used to explore the relationships between DOC concentration and BCC. We found a significant negative correlation between DOC concentration and bacterioplankton community diversity (as measured by the Shannon-Wiener index (H')). The results show that spatial variation in the bacterioplankton population was stronger than the seasonal variation and that DOC concentration influences BCC in Lake Taihu. DOC concentration, followed by macrophyte biomass, water turbidity, and phytoplankton biomass were the most influential factors that account for BCC changes in Lake Taihu. More detailed studies on the relationship between DOC concentration and BCC should focus on differences in DOC concentrations and quality among these lake regions. DOC had a significant impact on BCC in Meiliang Bay. The relationship between DOC and BCC in the 2 other regions studied (Lake Center and Eastern Taihu) was weaker. The results of this study add to our understanding of the BCC in eutrophic lakes, especially regarding the role of the microbial loop in lake ecosystems.

  20. Nearly a decade-long repeatable seasonal diversity patterns of bacterioplankton communities in the eutrophic Lake Donghu (Wuhan, China).

    Science.gov (United States)

    Yan, Qingyun; Stegen, James C; Yu, Yuhe; Deng, Ye; Li, Xinghao; Wu, Shu; Dai, Lili; Zhang, Xiang; Li, Jinjin; Wang, Chun; Ni, Jiajia; Li, Xuemei; Hu, Hongjuan; Xiao, Fanshu; Feng, Weisong; Ning, Daliang; He, Zhili; Van Nostrand, Joy D; Wu, Liyou; Zhou, Jizhong

    2017-07-01

    Uncovering which environmental factors govern community diversity patterns and how ecological processes drive community turnover are key questions related to understand the community assembly. However, the ecological mechanisms regulating long-term variations of bacterioplankton communities in lake ecosystems remain poorly understood. Here we present nearly a decade-long study of bacterioplankton communities from the eutrophic Lake Donghu (Wuhan, China) using 16S rRNA gene amplicon sequencing with MiSeq platform. We found strong repeatable seasonal diversity patterns in terms of both common (detected in more than 50% samples) and dominant (relative abundance >1%) bacterial taxa turnover. Moreover, community composition tracked the seasonal temperature gradient, indicating that temperature is a key environmental factor controlling observed diversity patterns. Total phosphorus also contributed significantly to the seasonal shifts in bacterioplankton composition. However, any spatial pattern of bacterioplankton communities across the main lake areas within season was overwhelmed by their temporal variabilities. Phylogenetic analysis further indicated that 75%-82% of community turnover was governed by homogeneous selection due to consistent environmental conditions within seasons, suggesting that the microbial communities in Lake Donghu are mainly controlled by niche-based processes. Therefore, dominant niches available within seasons might be occupied by similar combinations of bacterial taxa with modest dispersal rates throughout different lake areas. © 2017 John Wiley & Sons Ltd.

  1. Stimulated bacterioplankton growth and selection for certain bacterial taxa in the vicinity of the ctenophore Mnemiopsis leidyi.

    Science.gov (United States)

    Dinasquet, Julie; Granhag, Lena; Riemann, Lasse

    2012-01-01

    Episodic blooms of voracious gelatinous zooplankton, such as the ctenophore Mnemiopsis leidyi, affect pools of inorganic nutrients and dissolved organic carbon by intensive grazing activities and mucus release. This will potentially influence bacterioplankton activity and community composition, at least at local scales; however, available studies on this are scarce. In the present study we examined effects of M. leidyi on bacterioplankton growth and composition in incubation experiments. Moreover, we examined community composition of bacteria associated with the surface and gut of M. leidyi. High release of ammonium and high bacterial growth was observed in the treatments with M. leidyi relative to controls. Deep 454 pyrosequencing of 16 S rRNA genes showed specific bacterial communities in treatments with M. leidyi as well as specific communities associated with M. leidyi tissue and gut. In particular, members of Flavobacteriaceae were associated with M. leidyi. Our study shows that M. leidyi influences bacterioplankton activity and community composition in the vicinity of the jellyfish. In particular during temporary aggregations of jellyfish, these local zones of high bacterial growth may contribute significantly to the spatial heterogeneity of bacterioplankton activity and community composition in the sea.

  2. Stimulated bacterioplankton growth and selection for certain bacterial taxa in the vicinity of the ctenophore Mnemiopsis leidyi

    Directory of Open Access Journals (Sweden)

    Julie eDinasquet

    2012-08-01

    Full Text Available Episodic blooms of voracious gelatinous zooplankton, such as the ctenophore Mnemiopsis leidyi, affect pools of inorganic nutrients and dissolved organic carbon by intensive grazing activities and mucus release. This will potentially influence bacterioplankton activity and community composition, at least at local scales; however, available studies on this are scarce. In the present study we examined effects of M. leidyi on bacterioplankton growth and composition in incubation experiments. Moreover, we examined community composition of bacteria associated with the surface and gut of M. leidyi. High release of ammonium and high bacterial growth was observed in the treatments with M. leidyi relative to controls. Deep 454 pyrosequencing of 16S rRNA genes showed specific bacterial communities in treatments with M. leidyi as well as specific communities associated with M. leidyi tissue and gut. In particular, members of Flavobacteriaceae were associated with M. leidyi. Our study shows that M. leidyi influences bacterioplankton activity and community composition in the vicinity of the jellyfish. In particular during temporary aggregations of jellyfish, these local zones of high bacterial growth may contribute significantly to the spatial heterogeneity of bacterioplankton activity and community composition in the sea.

  3. Macrophytes and periphyton carbon subsidies to bacterioplankton and zooplankton in a shallow eutrophic lake in tropical China

    NARCIS (Netherlands)

    De Kluijver, A.; Ning, J.; Liu, Z.; Jeppesen, E.; Gulati, R.D.; Middelburg, J.J.

    2015-01-01

    The subsidy of carbon derived from macrophytes and associated periphyton to bacterioplankton and zooplankton in subtropical shallow eutrophic Huizhou West Lake in China was analyzed using carbon stable isotope signatures. A restored part of the lake dominated by macrophytes was compared with an

  4. Nearly a decade-long repeatable seasonal diversity patterns of bacterioplankton communities in the eutrophic Lake Donghu (Wuhan, China)

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Qingyun [Environmental Microbiome Research Center and the School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou China; Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Stegen, James C. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland WA USA; Yu, Yuhe [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Deng, Ye [CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing China; Li, Xinghao [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Wu, Shu [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Dai, Lili [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Zhang, Xiang [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Li, Jinjin [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Wang, Chun [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Ni, Jiajia [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Li, Xuemei [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Hu, Hongjuan [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Xiao, Fanshu [Environmental Microbiome Research Center and the School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou China; Feng, Weisong [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan China; Ning, Daliang [Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of Oklahoma, Norman OK USA; He, Zhili [Environmental Microbiome Research Center and the School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou China; Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of Oklahoma, Norman OK USA; Van Nostrand, Joy D. [Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of Oklahoma, Norman OK USA; Wu, Liyou [Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of Oklahoma, Norman OK USA; Zhou, Jizhong [Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of Oklahoma, Norman OK USA; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing China; Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA USA

    2017-05-21

    Uncovering which environmental factors have the greatest influence on community diversity patterns and how ecological processes govern community turnover are key questions related to understanding community assembly mechanisms. Although we have good understanding of plant and animal community assembly, the mechanisms regulating diversity patterns of aquatic bacterial communities in lake ecosystems remains poorly understood. Here we present nearly a decade-long time-series study of bacterioplankton communities from the eutrophic Lake Donghu (Wuhan, China) using 16S rRNA gene amplicon sequencing. We found strong repeatable seasonal patterns for the overall community, common (detected in more than 50% samples) and dominant bacterial taxa (relative abundance > 1%). Moreover, community composition tracked the seasonal temperature gradient, indicating that temperature is an important environmental factor controlling observed diversity patterns. Total phosphorus also contributed significantly to the seasonal shifts in bacterioplankton composition. However, any spatial pattern across the main lake areas was overwhelmed by temporal variability in this eutrophic lake system. Phylogenetic analysis further indicated that 75%-82% of community turnover was governed by homogeneous selection, suggesting that the bacterioplankton communities are mainly controlled by niche-based processes. However, dominant niches available within seasons might be occupied by similar combinations of bacterial taxa with modest dispersal rates throughout this lake system. This study gives us important insights into community assembly and seasonal turnover of lake bacterioplankton, it may be also useful to predict temporal patterns of other planktonic communities.

  5. Implications of Boy Scout group use of public lands for natural resource managers: a regional comparison

    Science.gov (United States)

    Gail A. Vander Stoep

    1992-01-01

    Resource managers can apply group-specific rather than generic communications and management strategies to different public land user groups. This study compares use patterns of one user group, Boy Scout troops, from two regions of the United States. It identifies their public land use patterns, activities, needs, and motivations. Results can be used by resource...

  6. Relation between presence-absence of a visible nucleoid and metabolic activity in bacterioplankton cells

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Joon, W.; Sherr, E.B.; Sherr, B.F. [Oregon State Univ., Corvallis, OR (United States)

    1996-09-01

    We investigated the report of Zweifel and Hagstroem that only a portion of marine bacteria contain nucleoids--the DNA-containing regions of procaryotic cells-- and that such bacteria correspond to the active or viable fraction of bacterioplankton. In Oregon coastal waters, 21-64% of bacteria had visible nucleoids; number of nucleoid-visible (NV) bacteria were greater than numbers of metabolically active bacteria, based on cells with active electron transport systems (ETS) and intact cell membranes. During log growth of a marine isolate, proportions of NV and ETS-active cells approached 100%. In stationary growth phase, the fraction of ETS-active cells decreased rapidly, while that of NV cells remained high for 7 d. When starved cells of the isolate were resupplied with nutrient (50 mg liter{sup -1} peptone), total cell number did not increase during the initial 6 h, but the proportion of NV cells increased from 27 to 100%, and that of ETS-active cells from 6 to 75%. In an analogous experiment with a bacterioplankton assemblage, a similar trend was observed: the number of NV cells double during the initial 6 h prior to an increase in total cell counts. These results show that some bacteria without visible nucleoids are capable of becoming NV cells, and thus have DNa in a nucleoid region not detectable with the method used here. 18 refs., 4 figs., 1 tab.

  7. Differential impact of lytic viruses on the taxonomical resolution of freshwater bacterioplankton community structure.

    Science.gov (United States)

    Keshri, Jitendra; Pradeep Ram, Angia Sriram; Colombet, Jonathan; Perriere, Fanny; Thouvenot, Antoine; Sime-Ngando, Télesphore

    2017-11-01

    The significance of lytic viral lysis in shaping bacterial communities in temperate freshwater systems is less documented. Here we used Illumina sequencing of 16S rRNA genes to examine bacterial community structure and diversity in relation to variable viral lysis in the euphotic zone of 25 temperate freshwater lakes (French Massif Central). We captured a rich bacterial community that was dominated by a few bacterial classes and operational taxonomic units (OTUs) frequently detected in other freshwater ecosystems. In the investigated lakes with contrasting physico-chemical characteristics, the dominant bacterioplankton community was represented by major taxonomical orders, namely Actinomycetales, Burkholderiales, Sphingobacteriales, Acidimicrobiales, Flavobacteriales and Cytophagales covering about 70% of all sequences. Viral lysis was significantly correlated with the bacterial diversity indices (Chao, Shannon, OTUs) which explained about 33% and 45% of the variation in species diversity and observed richness respectively. Anosim and UniFrac analyses indicated a clear distinction of bacterial community structure among the lakes that exhibited high and low lytic viral infection (FIC) rates. Based on our findings, high FIC (>10%) supported higher species richness, whereas low FIC (bacterioplankton diversity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Occurrence of Plasmids in the Aromatic Degrading Bacterioplankton of the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Ain Heinaru

    2011-11-01

    Full Text Available Plasmids are mobile genetic elements that provide their hosts with many beneficial traits including in some cases the ability to degrade different aromatic compounds. To fulfill the knowledge gap regarding catabolic plasmids of the Baltic Sea water, a total of 209 biodegrading bacterial strains were isolated and screened for the presence of these mobile genetic elements. We found that both large and small plasmids are common in the cultivable Baltic Sea bacterioplankton and are particularly prevalent among bacterial genera Pseudomonas and Acinetobacter. Out of 61 plasmid-containing strains (29% of all isolates, 34 strains were found to carry large plasmids, which could be associated with the biodegradative capabilities of the host bacterial strains. Focusing on the diversity of IncP-9 plasmids, self-transmissible m-toluate (TOL and salicylate (SAL plasmids were detected. Sequencing the repA gene of IncP-9 carrying isolates revealed a high diversity within IncP-9 plasmid family, as well as extended the assumed bacterial host species range of the IncP-9 representatives. This study is the first insight into the genetic pool of the IncP-9 catabolic plasmids in the Baltic Sea bacterioplankton.

  9. Detection of bacterioplankton using PCR probes as a diagnostic indicator for drowning; the Leicester experience.

    Science.gov (United States)

    Rutty, Guy N; Bradley, Carina J; Biggs, Mike J P; Hollingbury, Frances E; Hamilton, Stuart J; Malcomson, Roger D G; Holmes, Christopher W

    2015-09-01

    Bodies found immersed in water can pose difficulties to the investigating authorities. Pathologists may be assisted with the diagnosis by the use of tests such as the analysis for diatoms or the levels of strontium in the blood, although there is a recognised level of uncertainty associated with these tests. Recent work from Japan has shown that using molecular approaches, most recently real-time polymerase chain reaction (PCR) assays with TaqMan probes for bacterioplankton, it is possible to undertake rapid, less laborious, high throughput tests to differentiate freshwater from marine bacterioplankton and in doing so provide a molecular diagnostic test to assist in the diagnosis of drowning. We report the experiences of a United Kingdom forensic pathology unit in the use of this PCR based system for the diagnosis of drowning. We applied this technique to 20 adult and child cadavers from 4 bath, 12 freshwater, 2 brackish and 2 salt water scenes both from within the United Kingdom and abroad. Drowning was concluded to be the cause of death in 16 of these 20 cases and the PCR method supported this conclusion in 12 of these 16 cases. The PCR did not provide evidence of drowning in the four cases where death was from other causes. We illustrate that this PCR method provides a rapid diagnostic supportive test for the diagnosis of drowning that can be applied to United Kingdom autopsy practice. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. Bacterioplankton abundance, biomass and production in a Brazilian coastal lagoon and in two German lakes

    Directory of Open Access Journals (Sweden)

    FURTADO ANDRÉ L. S.

    2001-01-01

    Full Text Available The bacterioplanktonic abundance, biomass, and production within a tropical lagoon (Cabiúnas, Brazil and two temperate lakes (Stechlin and Dagow, Germany were compared. Bacterial abundance and production were significantly different among the three water bodies. The lowest bacterial production ( 0.8mug C l-1 d-1 was observed in the tropical Cabiúnas Lagoon despite its higher mean temperature and dissolved organic carbon concentration. Highest bacterioplankton abundance ( 2.6 x 10(9 cells l-1 and production ( 68.5mug C l-1 d-1 were measured in eutrophic Lake Dagow. In oligotrophic Lake Stechlin, the lowest bacterial biomass ( 48.05mug C l-1 was observed because of lower bacterial biovolume ( 0.248mum³ and lower bacterial abundance. Bacterial populations in the temperate lakes show higher activity (production/biomass ratio than in the tropical lagoon. The meaning of isotopic dilution and leucine incorporation by non-bacterial micro-organisms were evaluated in the oligotrophic temperate system. Leucine uptake by non-bacterial micro-organisms did not have significant influence on bacterial production.

  11. Identification of Associations between Bacterioplankton and Photosynthetic Picoeukaryotes in Coastal Waters

    Directory of Open Access Journals (Sweden)

    Hanna Maria Farnelid

    2016-03-01

    Full Text Available Photosynthetic picoeukaryotes are significant contributors to marine primary productivity. Associations between marine bacterioplankton and picoeukaryotes frequently occur and can have large biogeochemical impacts. We used flow cytometry to sort cells from seawater to identify non-eukaryotic phylotypes that are associated with photosynthetic picoeukaryotes. Samples were collected at the Santa Cruz wharf on Monterey Bay, California during summer and fall, 2014. The phylogeny of associated microbes was assessed through 16S rRNA gene amplicon clone and Illumina MiSeq libraries. The most frequently detected bacterioplankton phyla within the photosynthetic picoeukaryote sorts were Proteobacteria (Alphaproteobacteria and Gammaproteobacteria and Bacteroidetes. Intriguingly, the presence of free-living bacterial genera in the photosynthetic picoeukaryote sorts could suggest that some of the photosynthetic picoeukaryotes were mixotrophs. However, the occurrence of bacterial sequences, which were not prevalent in the corresponding bulk seawater samples, indicates that there was also a selection for specific OTUs in association with photosynthetic picoeukaryotes suggesting specific functional associations. The results show that diverse bacterial phylotypes are found in association with photosynthetic picoeukaryotes. Taxonomic identification of these associations is a prerequisite for further characterizing and to elucidate their metabolic pathways and ecological functions.

  12. Network analysis reveals seasonal variation of co-occurrence correlations between Cyanobacteria and other bacterioplankton.

    Science.gov (United States)

    Zhao, Dayong; Shen, Feng; Zeng, Jin; Huang, Rui; Yu, Zhongbo; Wu, Qinglong L

    2016-12-15

    Association network approaches have recently been proposed as a means for exploring the associations between bacterial communities. In the present study, high-throughput sequencing was employed to investigate the seasonal variations in the composition of bacterioplankton communities in six eutrophic urban lakes of Nanjing City, China. Over 150,000 16S rRNA sequences were derived from 52 water samples, and correlation-based network analyses were conducted. Our results demonstrated that the architecture of the co-occurrence networks varied in different seasons. Cyanobacteria played various roles in the ecological networks during different seasons. Co-occurrence patterns revealed that members of Cyanobacteria shared a very similar niche and they had weak positive correlations with other phyla in summer. To explore the effect of environmental factors on species-species co-occurrence networks and to determine the most influential environmental factors, the original positive network was simplified by module partitioning and by calculating module eigengenes. Module eigengene analysis indicated that temperature only affected some Cyanobacteria; the rest were mainly affected by nitrogen associated factors throughout the year. Cyanobacteria were dominant in summer which may result from strong co-occurrence patterns and suitable living conditions. Overall, this study has improved our understanding of the roles of Cyanobacteria and other bacterioplankton in ecological networks. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Impact of photochemical processing of DOC on the bacterioplankton respiratory quotient in aquatic ecosystems

    Science.gov (United States)

    Allesson, Lina; Ström, Lena; Berggren, Martin

    2016-07-01

    Many studies assume a respiratory quotient (RQ = molar ratio of CO2 produced to O2 consumed) close to 1 when calculating bacterioplankton respiration. However, evidence suggests that RQ depends on the chemical composition of the respired substrate pool that may be altered by photochemical production of oxygen-rich substrates, resulting in elevated RQs. Here we conducted a novel study of the impact of photochemical processing of dissolved organic carbon (DOC) on RQ. We monitored the bacterial RQ in bioassays of both ultraviolet light irradiated and nonirradiated humic lake water, using optic gas-pressure sensors. In the experimentally irradiated samples the average RQ value was significantly higher (3.4-3.5 [±0.4 standard error (SE)]) than that in the dark controls (1.3 [±0.1 SE]). Our results show that the RQ is systematically higher than 1 when the bacterial metabolism in large part is based on photoproducts. By assuming an RQ of 1, bacterioplankton respiration in freshwater ecosystems may be greatly underestimated.

  14. Dispersal timing and drought history influence the response of bacterioplankton to drying-rewetting stress.

    Science.gov (United States)

    Székely, Anna J; Langenheder, Silke

    2017-08-01

    The extent and frequency of drought episodes is expected to increase in the following decades making it a crucial stress factor for smaller water bodies. However, very little is known about how bacterioplankton is affected by increased evaporation and how these communities reassemble after rewetting. Here, we present results from a microcosm experiment that assessed the effect of drying-rewetting stress on bacterioplankton in the light of the stress history and the rate and timing of dispersal after the rewetting. We found that the drying phase resulted mainly in a change of function, whereas the complete desiccation and rewetting processes strongly affected both composition and function, which were, however, influenced by the initial conditions and stress history of the communities. Effects of dispersal were generally stronger when it occurred at an early stage after the rewetting. At this stage, selective establishment of dispersed bacteria coupled with enhanced compositional and functional recovery was found, whereas effects of dispersal were neutral, that is, predictable by dispersal rates, at later stages. Our studies therefore show that both the stress history and the timing of dispersal are important factors that influence the response of bacterial communities to environmental change and stress events.

  15. The influence of status on group drinking by young adults: a survey of natural drinking groups on their way to and from bars.

    Science.gov (United States)

    Dumas, Tara M; Wells, Samantha; Flynn, Andrea; Lange, James E; Graham, Kathryn

    2014-04-01

    Young people's social standing among friends and peers has been linked to general levels of drinking and has been shown to influence others' drinking. We extend previous research by examining young adults' status within their natural-occurring drinking groups as a predictor of their subsequent alcohol consumption and encouragement of group members' alcohol consumption during a night out at licensed drinking establishments, a salient context for heavy drinking and alcohol-related risk among young adults. We recruited same-sex young adult drinking groups (n = 104 groups; 63 all-male; average group size = 3.4 members; Mage = 21.86) on their way to drinking establishments to complete a survey-containing measures of member-nominated within-group status, likeability, and self-reported alcohol consumption-and a breathalyzer test. At the end of the evening, participants completed the same alcohol consumption measures and were asked to nominate group members who encouraged other members to drink that night. Multilevel analysis revealed that higher-status members engaged in the most alcohol consumption (via both self-report and breathalyzer) but in heavier drinking groups only. Higher-status members also encouraged the most alcohol consumed by others, regardless of levels of group drinking. Further, even though being liked by one's peers was positively related to intoxication that night, it did not account for the significant relationship between within-group status and drinking. Results suggest that peer-related prevention programs for young adults' problem drinking may benefit from focusing on the structure and dynamic of young people's drinking groups. Also, programs targeting peer norms may be more successful if they incorporate status-related issues. Copyright © 2013 by the Research Society on Alcoholism.

  16. Post-mortem computed tomography coaxial cutting needle biopsy to facilitate the detection of bacterioplankton using PCR probes as a diagnostic indicator for drowning

    OpenAIRE

    Rutty, Guy N.; Johnson, Christopher; Amoroso, Jasmin; Robinson, Claire; Bradley, Carina J.; Morgan, Bruno

    2016-01-01

    We report for the first time the use of coaxial cutting needle biopsy, guided by post-mortem computed tomography (PMCT), to sample internal body tissues for bacterioplankton PCR analysis to investigate drowning. This technical report describes the biopsy technique, the comparison of the needle biopsy and the invasive autopsy sampling results, as well as the PMCT and autopsy findings. By using this new biopsy sampling approach for bacterioplankton PCR, we have developed on previous papers desc...

  17. Species groups occupying different trophic levels respond differently to the invasion of semi-natural vegetation by Solidago canadensis

    NARCIS (Netherlands)

    Groot, de M.; Kleijn, D.; Jogan, N.

    2007-01-01

    We studied the impact of the invasive plant species Solidago canadensis on the species richness of vascular plants and the abundance, species richness and diversity of butterflies, hoverflies and carabid beetles in herbaceous semi-natural habitats near Ljubljana, Slovenia. The species groups were

  18. On the triplet nature of excited states of group IVB metallocenes

    International Nuclear Information System (INIS)

    Lukova, G.V.; Smirnov, V.A.; Starodubova, S.E.

    2005-01-01

    Direct photophysical approach is presented to estimation of energy and orbital nature of electron-excited states of metalorganic compounds of transition metals (Ti, Zr, Hf) by nonradiating triplet-triplet energy transfer from metalorganic complexes to unsaturated hydrocarbons having strong S-T-splitting energy. It is proved for the first time that emission excites states of metallocenes Cp 2 M IV Cl 2 are triplet and their emission is accordingly phosphorescence [ru

  19. Late-stage chemoselective functional-group manipulation of bioactive natural products with super-electrophilic silylium ions

    Science.gov (United States)

    Bender, Trandon A.; Payne, Philippa R.; Gagné, Michel R.

    2018-01-01

    The selective (and controllable) modification of complex molecules with disparate functional groups (for example, natural products) is a long-standing challenge that has been addressed using catalysts tuned to perform singular transformations (for example, C-H hydroxylation). A method whereby reactions with diverse functional groups within a single natural product are feasible depending on which catalyst or reagent is chosen would widen the possible structures one could obtain. Fluoroarylborane catalysts can heterolytically split Si-H bonds to yield an oxophilic silylium (R3Si+) equivalent along with a reducing (H-) equivalent. Together, these reactive intermediates enable the reduction of multiple functional groups. Exogenous phosphine Lewis bases further modify the catalyst speciation and attenuate aggressive silylium ions for the selective modification of complex natural products. Manipulation of the catalyst, silane reagent and the reaction conditions provides experimental control over which site is modified (and how). Applying this catalytic method to complex bioactive compounds (natural products or drugs) provides a powerful tool for studying structure-activity relationships.

  20. Low-temperature calorimetric and magnetic data for natural end-members of the axinite group

    Czech Academy of Sciences Publication Activity Database

    Filip, J.; Dachs, E.; Tuček, J.; Novák, M.; Bezdička, Petr

    2008-01-01

    Roč. 93, č. 4 (2008), s. 548-557 ISSN 0003-004X Institutional research plan: CEZ:AV0Z40320502 Keywords : axinite group minerals * chemical composition * heat capacity Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.962, year: 2008

  1. Human genetic studies in areas of high natural radiation VI. Genetical load and ethnic group

    International Nuclear Information System (INIS)

    Freire-Maia, A.

    1974-01-01

    The load of mutations disclosed by inbreeding, according to the ethnic group of the parents, has been analyzed in our data. Besides the total of the population, a sample with no alien ancestrals has also been analyzed. Genetic load has been studied for absortions, still births, pos-natal mortality, total mortality, anomalies, total mortality + anomalies, and abnormalities in general [pt

  2. Group Decision Making with Responses of a Quantitative Nature: The Theory of Social Decision Schemes for Quantities.

    Science.gov (United States)

    Hinsz

    1999-10-01

    Group decisions involving responses of a quantitative nature occur frequently in organizations. Although extensive research has considered group decisions involving discrete responses, only recently have responses involving quantities received comparable attention. It is proposed that the group decision processes related to quantities involve compromise and are characteristically different from the consensus processes that occur for discrete choices. The theory of social decision schemes (Davis, 1973) as originally formulated is intractable for quantitative responses because they involve a large number of response alternatives. This paper extends and adapts the theory of social decision schemes to apply it to group decisions of a quantitative nature. The decision schemes considered in modeling group decisions for quantitative responses also differ from those of discrete responses. The classes of decision schemes considered include central tendency, consensus-based, faction-attraction, coalition, distance-influence, dictator, special cases, and other. Unique approaches for evaluating the adequacy of these decision schemes for quantities are considered. An illustration of the theory of social decision schemes for quantities is presented with data from research on group goal decisions (Hinsz, 1991). Copyright 1999 Academic Press.

  3. Exploiting natural killer group 2D receptors for CAR T-cell therapy.

    Science.gov (United States)

    Demoulin, Benjamin; Cook, W James; Murad, Joana; Graber, David J; Sentman, Marie-Louise; Lonez, Caroline; Gilham, David E; Sentman, Charles L; Agaugue, Sophie

    2017-08-01

    Chimeric antigen receptors (CARs) are genetically engineered proteins that combine an extracellular antigen-specific recognition domain with one or several intracellular T-cell signaling domains. When expressed in T cells, these CARs specifically trigger T-cell activation upon antigen recognition. While the clinical proof of principle of CAR T-cell therapy has been established in hematological cancers, CAR T cells are only at the early stages of being explored to tackle solid cancers. This special report discusses the concept of exploiting natural killer cell receptors as an approach that could broaden the specificity of CAR T cells and potentially enhance the efficacy of this therapy against solid tumors. New data demonstrating feasibility of this approach in humans and supporting the ongoing clinical trial are also presented.

  4. Temporal Patterns in Bacterioplankton Community Composition in Three Reservoirs of Similar Trophic Status in Shenzhen, China

    Directory of Open Access Journals (Sweden)

    Jiancheng Li

    2016-06-01

    Full Text Available The bacterioplankton community composition’s (BCC spatial and temporal variation patterns in three reservoirs (Shiyan, Xikeng, and LuoTian Reservoir of similar trophic status in Bao’an District, Shenzhen (China, were investigated using PCR amplification of the 16S rDNA gene and the denaturing gradient gel electrophoresis (DGGE techniques. Water samples were collected monthly in each reservoir during 12 consecutive months. Distinct differences were detected in band number, pattern, and density of DGGE at different sampling sites and time points. Analysis of the DGGE fingerprints showed that changes in the bacterial community structure mainly varied with seasons, and the patterns of change indicated that seasonal forces might have a more significant impact on the BCC than eutrophic status in the reservoirs, despite the similar Shannon-Weiner index among the three reservoirs. The sequences obtained from excised bands were affiliated with Cyanobacteria, Firmicutes, Bacteriodetes, Acidobacteria, Actinobacteria, Planctomycetes, and Proteobacteria.

  5. Temporal Patterns in Bacterioplankton Community Composition in Three Reservoirs of Similar Trophic Status in Shenzhen, China.

    Science.gov (United States)

    Li, Jiancheng; Chen, Cheng; Lu, Jun; Lei, Anping; Hu, Zhangli

    2016-06-16

    The bacterioplankton community composition's (BCC) spatial and temporal variation patterns in three reservoirs (Shiyan, Xikeng, and LuoTian Reservoir) of similar trophic status in Bao'an District, Shenzhen (China), were investigated using PCR amplification of the 16S rDNA gene and the denaturing gradient gel electrophoresis (DGGE) techniques. Water samples were collected monthly in each reservoir during 12 consecutive months. Distinct differences were detected in band number, pattern, and density of DGGE at different sampling sites and time points. Analysis of the DGGE fingerprints showed that changes in the bacterial community structure mainly varied with seasons, and the patterns of change indicated that seasonal forces might have a more significant impact on the BCC than eutrophic status in the reservoirs, despite the similar Shannon-Weiner index among the three reservoirs. The sequences obtained from excised bands were affiliated with Cyanobacteria, Firmicutes, Bacteriodetes, Acidobacteria, Actinobacteria, Planctomycetes, and Proteobacteria.

  6. Naturally occurring arsenic in the Miocene Hawthorn Group, southwestern Florida: Potential implication for phosphate mining

    International Nuclear Information System (INIS)

    Lazareva, Olesya; Pichler, Thomas

    2007-01-01

    To understand the mineralogical association, concentration, and distribution of arsenic (As) in the Hawthorn Group, the chemical and mineralogical composition of 362 samples that were collected from 16 cores in southwestern Florida were examined in detail. In the study area, the Hawthorn Group consisted primarily of a basal carbonate unit (the Arcadia Formation) and an upper siliciclastic unit (The Peace River Formation). The Peace River Formation contains appreciable amounts of phosphate and is currently being exploited for phosphate ore. Samples were taken from cores of each formation at intervals of 7.5 m. In addition, to the interval samples, sections likely to have high As concentrations, such as zones with pyrite crystals, hydrous ferric oxides, green clays, and organic material, were collected and analyzed. Bulk As concentrations were determined by hydride generation-atomic fluorescence spectrometry (HG-AFS) after digestion with aqua regia (3:1 HCl and HNO 3 ). The elements Fe, Al, Si, Mg, Ca, S, and P were measured on the same solutions by inductively coupled plasma optical emission spectrometry (ICP-OES). The identification of discrete minerals was aided by scanning electron microscopy (SEM) and chemical compositions within the sample matrix and in individual minerals were obtained by electron-probe microanalysis (EMPA). This detailed mineralogical and geochemical study demonstrated that: (1) As in the Hawthorn Group varied from formation to formation and was mostly concentrated in trace minerals, such as pyrite; (2) average As concentrations significantly changed from 8.8 mg/kg (σ = 8.6 mg/kg) in the Peace River Formation to 3.0 mg/kg (σ = 3.7 mg/kg) in the Tampa Member of the Arcadia Formation. Arsenic concentrations for all Hawthorn samples varied from 0.1 to 69.0 mg/kg; (3) pyrite, with one exception, occurred as framboids and was unevenly distributed throughout the Hawthorn Group; (4) pyrite framboids were located inside a francolite (carbonate

  7. Community-based educational intervention on necklace method as a natural family planning amongst reproductive age group women in India

    OpenAIRE

    Jyothi Ramesh; Ramesh Chandrababu

    2018-01-01

    Objective: To assess the effectiveness of a community-based educational intervention on necklace method as a natural family planning amongst reproductive age group women. This approach helps women decide on their reproductive health choices and avoid ill health, impact and long-term consequences of unwanted pregnancy that lead to unsafe abortion. Methods: A total of 120 women were selected using non-probability purposive sampling technique. The knowledge and practice of participants were a...

  8. Enhanced dispersion of multiwall carbon nanotubes in natural rubber latex nanocomposites by surfactants bearing phenyl groups.

    Science.gov (United States)

    Mohamed, Azmi; Anas, Argo Khoirul; Bakar, Suriani Abu; Ardyani, Tretya; Zin, Wan Manshol W; Ibrahim, Sofian; Sagisaka, Masanobu; Brown, Paul; Eastoe, Julian

    2015-10-01

    Here is presented a systematic study of the dispersibility of multiwall carbon nanotubes (MWCNTs) in natural rubber latex (NR-latex) assisted by a series of single-, double-, and triple-sulfosuccinate anionic surfactants containing phenyl ring moieties. Optical polarising microscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Raman spectroscopy have been performed to obtain the dispersion-level profiles of the MWCNTs in the nanocomposites. Interestingly, a triple-chain, phenyl-containing surfactant, namely sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3-phenylpropoxy)carbonyl) pentane-2-sulfonate (TCPh), has a greater capacity the stabilisation of MWCNTs than a commercially available single-chain sodium dodecylbenzenesulfonate (SDBS) surfactant. TCPh provides significant enhancements in the electrical conductivity of nanocomposites, up to ∼10(-2) S cm(-1), as measured by a four-point probe instrument. These results have allowed compilation of a road map for the design of surfactant architectures capable of providing the homogeneous dispersion of MWCNTs required for the next generation of polymer-carbon-nanotube materials, specifically those used in aerospace technology. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Opportunity for natural selection among some selected population groups of Northeast India

    Science.gov (United States)

    Das, Farida Ahmed; Mithun, Sikdar

    2010-01-01

    BACKGROUND: Selection potential based on differential fertility and mortality has been computed for seven population groups inhabiting different geographical locations of Northeast India. MATERIALS AND METHODS: Crow’s as well as Johnston and Kensinger’s index have been used for the present purpose. RESULTS AND CONCLUSION: Irrespective of the methodology, the total index of selection was found to be highest among the Deoris followed by the Kaibartas. The lowest selection index was found among the Oraon population. If the relative contribution of fertility and mortality components to the total index is considered to be multiplicative, it is observed that in all these communities the fertility component exceeds that of mortality component, which may indicate initiation of demographic transitional phase in the selected populations with the betterment of healthcare and socioeconomic condition within the last few decades. PMID:21031053

  10. Opportunity for natural selection among some selected population groups of Northeast India.

    Science.gov (United States)

    Das, Farida Ahmed; Mithun, Sikdar

    2010-05-01

    Selection potential based on differential fertility and mortality has been computed for seven population groups inhabiting different geographical locations of Northeast India. Crow's as well as Johnston and Kensinger's index have been used for the present purpose. Irrespective of the methodology, the total index of selection was found to be highest among the Deoris followed by the Kaibartas. The lowest selection index was found among the Oraon population. If the relative contribution of fertility and mortality components to the total index is considered to be multiplicative, it is observed that in all these communities the fertility component exceeds that of mortality component, which may indicate initiation of demographic transitional phase in the selected populations with the betterment of healthcare and socioeconomic condition within the last few decades.

  11. Gauge Group Contraction of Electroweak Model and its Natural Energy Limits

    Directory of Open Access Journals (Sweden)

    Nikolai A. Gromov

    2015-09-01

    Full Text Available The low and higher energy limits of the Electroweak Model are obtained from first principles of gauge theory. Both limits are given by the same contraction of the gauge group, but for the different consistent rescalings of the field space. Mathematical contraction parameter in both cases is interpreted as energy. The very weak neutrino-matter interaction is explained by zero tending contraction parameter, which depends on neutrino energy. The second consistent rescaling corresponds to the higher energy limit of the Electroweak Model. At the infinite energy all particles lose masses, electroweak interactions become long-range and are mediated by the neutral currents. The limit model represents the development of the early Universe from the Big Bang up to the end of the first second.

  12. Measurement of the natural radiation environment and its dependence on various parameters in Austria and assessment of the natural external and internal radiation dose of various population groups

    International Nuclear Information System (INIS)

    Pohl, E.

    1978-06-01

    The natural mean values of natural radionuclides in the air and external gamma radiation were determined from measurements carried out in various parts of Austria and the mean values were used as a basis for the determination of body and organ doses. Moreover frequency distributions of several specific organ doses within various population groups were investigated. Measurements of natural air activity were carried out indoors and outdoors as well as gamma radiation at the following sites - Salzburg Town, Badgastein, Gastein Valley and Mallnitz and several other places at a line crossing the Alps from South to North (Corinthia, Schwarzach, Forstau, Hallein, Kuchl, Grodig and Voggenberg - Bergheim) and in 15 different mines in the Counties of Salzburg and Upper Austria. The methods of calculation of the radiation burden due to inhalation is published in the Proceedings of the Symposium on Biological and Environmental Effects of Low Level Radiation, IAEA, Chicago 1976, Vol. II pages 305-315. It can be concluded from the work that great local differences of some components occur even within relatively small areas. The radioactivity in the air shows great temporal differences at one and the same site. In addition radiation doses had to be calculated separately for various organs and tissues due to the inhomogeneous distribution of doses within the body. Also the estimation had to be made for a variety of individuals depending on sex, age, weight and various physiological states of activity. The highest doses to tissues from inhalation of natural radioactivity are the basal cells of the sigmental epithelium and subsigmental bronchi 4th - 9th generation in the lung model of Weibel. 46% of the population investigated received more than 0.5 rem per year, 25% more than 1.5 rem per year and 1.3% more than 3 rem per year. The different air activities in the living and working rooms are due to differences in the building materials and in the construction of houses

  13. Response of bacterioplankton community structure to an artificial gradient of pCO2 in the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    R. Zhang

    2013-06-01

    Full Text Available In order to test the influences of ocean acidification on the ocean pelagic ecosystem, so far the largest CO2 manipulation mesocosm study (European Project on Ocean Acidification, EPOCA was performed in Kings Bay (Kongsfjorden, Spitsbergen. During a 30 day incubation, bacterial diversity was investigated using DNA fingerprinting and clone library analysis of bacterioplankton samples. Terminal restriction fragment length polymorphism (T-RFLP analysis of the PCR amplicons of the 16S rRNA genes revealed that general bacterial diversity, taxonomic richness and community structure were influenced by the variation of productivity during the time of incubation, but not the degree of ocean acidification. A BIOENV analysis suggested a complex control of bacterial community structure by various biological and chemical environmental parameters. The maximum apparent diversity of bacterioplankton (i.e., the number of T-RFs in high and low pCO2 treatments differed significantly. A negative relationship between the relative abundance of Bacteroidetes and pCO2 levels was observed for samples at the end of the experiment by the combination of T-RFLP and clone library analysis. Our study suggests that ocean acidification affects the development of bacterial assemblages and potentially impacts the ecological function of the bacterioplankton in the marine ecosystem.

  14. Response of bacterioplankton community structure to an artificial gradient of pCO2 in the Arctic Ocean

    Science.gov (United States)

    Zhang, R.; Xia, X.; Lau, S. C. K.; Motegi, C.; Weinbauer, M. G.; Jiao, N.

    2013-06-01

    In order to test the influences of ocean acidification on the ocean pelagic ecosystem, so far the largest CO2 manipulation mesocosm study (European Project on Ocean Acidification, EPOCA) was performed in Kings Bay (Kongsfjorden), Spitsbergen. During a 30 day incubation, bacterial diversity was investigated using DNA fingerprinting and clone library analysis of bacterioplankton samples. Terminal restriction fragment length polymorphism (T-RFLP) analysis of the PCR amplicons of the 16S rRNA genes revealed that general bacterial diversity, taxonomic richness and community structure were influenced by the variation of productivity during the time of incubation, but not the degree of ocean acidification. A BIOENV analysis suggested a complex control of bacterial community structure by various biological and chemical environmental parameters. The maximum apparent diversity of bacterioplankton (i.e., the number of T-RFs) in high and low pCO2 treatments differed significantly. A negative relationship between the relative abundance of Bacteroidetes and pCO2 levels was observed for samples at the end of the experiment by the combination of T-RFLP and clone library analysis. Our study suggests that ocean acidification affects the development of bacterial assemblages and potentially impacts the ecological function of the bacterioplankton in the marine ecosystem.

  15. Bacterioplankton community responses to key environmental variables in plateau freshwater lake ecosystems: A structural equation modeling and change point analysis.

    Science.gov (United States)

    Cao, Xiaofeng; Wang, Jie; Liao, Jingqiu; Gao, Zhe; Jiang, Dalin; Sun, Jinhua; Zhao, Lei; Huang, Yi; Luan, Shengji

    2017-02-15

    Elevated environmental pressures negatively affect the bacterial community structure. However, little knowledge about the nonlinear responses of spatially related environmental variable across multiple plateau lake ecosystems on bacterioplankton communities has been gathered. Here, we used 454 pyrosequencing of 16S rRNA genes to study the associations of bacterial communities in terms of environmental characteristics as well as the potentially ecological threshold-inducing shifts of the bacterial community structure along the key environmental variables based on hypothesized structural equation models and the SEGMENTED method in 21 plateau lakes. Our results showed that water transparency was the major driving force and that total nitrogen was more significant than total phosphorus in determining the taxon composition of the bacterioplankton community. Significant community threshold estimates for bacterioplankton were observed at 7.36 for pH and 25.6% for the percentage of the agricultural area, while the remarkable change point of the cyanobacteria community structure responding to pH was at 7.74. Furthermore, the findings indicated that increasing nutrient loads can induce a distinct shift in dominance from Proteobacteria to Cyanobacteria, as well as a sharp decrease and adjacent increase when crossing the change point for Actinobacteria and Bacteroidetes along the gradient of the agricultural area. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Modeling the impact of riverine DON removal by marine bacterioplankton on primary production in the Arctic Ocean

    Science.gov (United States)

    Le Fouest, V.; Manizza, M.; Tremblay, B.; Babin, M.

    2014-12-01

    The planktonic and biogeochemical dynamics of the Arctic shelves exhibit a strong variability in response to Arctic warming. In this study, in order to elucidate on the processes regulating the production of phytoplankton (PP) and bacterioplankton (BP) and their interactions, we employ a biogeochemical model coupled to a pan-Arctic ocean-sea ice model (MITgcm) to explicitly simulate and quantify the contribution of usable dissolved organic nitrogen (DON) drained by the major circum-Arctic rivers on PP and BP in a scenario of melting sea ice (1998-2011). Model simulations suggest that on average between 1998 and 2011, the removal of usable RDON by bacterioplankton is responsible of a ~26% increase of the annual BP for the whole Arctic Ocean. With respect to total PP, the model simulates an increase of ~8% on an annual basis and of ~18% in summer. Recycled ammonium is responsible for the PP increase. The recycling of RDON by bacterioplankton promotes higher BP and PP but there is no significant temporal trend in the BP : PP ratio within the ice-free shelves over the 1998-2011 period. This suggests no significant evolution in the balance between autotrophy and heterotrophy in the last decade with a constant annual flux of RDON into the coastal ocean although changes in RDON supply and further reduction in sea ice cover could potentially alter this delicate balance.

  17. Seasonality Affects the Diversity and Composition of Bacterioplankton Communities in Dongjiang River, a Drinking Water Source of Hong Kong

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2017-08-01

    Full Text Available Water quality ranks the most vital criterion for rivers serving as drinking water sources, which periodically changes over seasons. Such fluctuation is believed associated with the state shifts of bacterial community within. To date, seasonality effects on bacterioplankton community patterns in large rivers serving as drinking water sources however, are still poorly understood. Here we investigated the intra-annual bacterial community structure in the Dongjiang River, a drinking water source of Hong Kong, using high-throughput pyrosequencing in concert with geochemical property measurements during dry, and wet seasons. Our results showed that Proteobacteria, Actinobacteria, and Bacteroidetes were the dominant phyla of bacterioplankton communities, which varied in composition, and distribution from dry to wet seasons, and exhibited profound seasonal changes. Actinobacteria, Bacteroidetes, and Cyanobacteria seemed to be more associated with seasonality that the relative abundances of Actinobacteria, and Bacteroidetes were significantly higher in the dry season than those in the wet season (p < 0.01, while the relative abundance of Cyanobacteria was about 10-fold higher in the wet season than in the dry season. Temperature and NO3--N concentration represented key contributing factors to the observed seasonal variations. These findings help understand the roles of various bacterioplankton and their interactions with the biogeochemical processes in the river ecosystem.

  18. Modelling the impact of riverine DON removal by marine bacterioplankton on primary production in the Arctic Ocean

    Science.gov (United States)

    Le Fouest, V.; Manizza, M.; Tremblay, B.; Babin, M.

    2015-06-01

    The planktonic and biogeochemical dynamics of the Arctic shelves exhibit a strong variability in response to Arctic warming. In this study, we employ a biogeochemical model coupled to a pan-Arctic ocean-sea ice model (MITgcm) to elucidate the processes regulating the primary production (PP) of phytoplankton, bacterioplankton (BP), and their interactions. The model explicitly simulates and quantifies the contribution of usable dissolved organic nitrogen (DON) drained by the major circum-Arctic rivers to PP and BP in a scenario of melting sea ice (1998-2011). Model simulations suggest that, on average between 1998 and 2011, the removal of usable riverine dissolved organic nitrogen (RDON) by bacterioplankton is responsible for a ~ 26% increase in the annual BP for the whole Arctic Ocean. With respect to total PP, the model simulates an increase of ~ 8% on an annual basis and of ~ 18% in summer. Recycled ammonium is responsible for the PP increase. The recycling of RDON by bacterioplankton promotes higher BP and PP, but there is no significant temporal trend in the BP : PP ratio within the ice-free shelves over the 1998-2011 period. This suggests no significant evolution in the balance between autotrophy and heterotrophy in the last decade, with a constant annual flux of RDON into the coastal ocean, although changes in RDON supply and further reduction in sea-ice cover could potentially alter this delicate balance.

  19. Seasonality Affects the Diversity and Composition of Bacterioplankton Communities in Dongjiang River, a Drinking Water Source of Hong Kong.

    Science.gov (United States)

    Sun, Wei; Xia, Chunyu; Xu, Meiying; Guo, Jun; Sun, Guoping

    2017-01-01

    Water quality ranks the most vital criterion for rivers serving as drinking water sources, which periodically changes over seasons. Such fluctuation is believed associated with the state shifts of bacterial community within. To date, seasonality effects on bacterioplankton community patterns in large rivers serving as drinking water sources however, are still poorly understood. Here we investigated the intra-annual bacterial community structure in the Dongjiang River, a drinking water source of Hong Kong, using high-throughput pyrosequencing in concert with geochemical property measurements during dry, and wet seasons. Our results showed that Proteobacteria, Actinobacteria , and Bacteroidetes were the dominant phyla of bacterioplankton communities, which varied in composition, and distribution from dry to wet seasons, and exhibited profound seasonal changes. Actinobacteria, Bacteroidetes , and Cyanobacteria seemed to be more associated with seasonality that the relative abundances of Actinobacteria , and Bacteroidetes were significantly higher in the dry season than those in the wet season ( p bacterioplankton and their interactions with the biogeochemical processes in the river ecosystem.

  20. Distribution of bacterioplankton with active metabolism in waters of the St. Anna Trough, Kara Sea, in autumn 2011

    Science.gov (United States)

    Mosharova, I. V.; Mosharov, S. A.; Ilinskiy, V. V.

    2017-01-01

    The distribution of bacterioplankton with active electron transport chains, as well as bacteria with intact cell membranes, was investigated for the first time in the region of St. Anna Trough in the Kara Sea. The average number of bacteria with active electron transport chains in the waters of the St. Anna Trough was 15.55 × 103 cells mL-1 (the limits of variation were 1.06-92.17 × 103 cells mL-1). The average number of bacteria with intact membranes was 33.46 × 103 cells mL-1 (the limits of variation were 6.78 to 103.18 × 103 cells mL-1). Almost all bacterioplankton microorganisms in the studied area were potentially viable, and the average share of bacteria with intact membranes was 92.1% of the total number of bacterioplankton (TNB) (the limits of variation were 76.2 to 98.4%). The share of bacteria with active metabolisms was 38.2% of the TNB (the limits of variation were 5.6-93.4%). The shares of the bacteria with active metabolisms were maximum in areas with the most stable environmental conditions (on the shelf and in deep water), whereas on the slope, where the gradients of water temperature and salinity were maximum, these values were lower.

  1. Comparative analysis of deep-sea bacterioplankton OMICS revealed the occurrence of habitat-specific genomic attributes.

    Science.gov (United States)

    Smedile, Francesco; Messina, Enzo; La Cono, Violetta; Yakimov, Michail M

    2014-10-01

    Bathyal aphotic ocean represents the largest biotope on our planet, which sustains highly diverse but low-density microbial communities, with yet untapped genomic attributes, potentially useful for discovery of new biomolecules, industrial enzymes and pathways. In the last two decades, culture-independent approaches of high-throughput sequencing have provided new insights into structure and function of marine bacterioplankton, leading to unprecedented opportunities to accurately characterize microbial communities and their interactions with the environments. In the present review we focused on the analysis of relatively few deep-sea OMICS studies, completed thus far, to find the specific genomic patterns determining the lifeway and adaptation mechanisms of prokaryotes thriving in the dark deep ocean below the depth of 1000m. Phylogenomic and omic studies provided clear evidence that the bathyal microbial communities are distinct from the epipelagic counterparts and, along with generally larger genomes, possess their own habitat-specific genomic attributes. The high abundance in the deep ocean OMICS of the systems for environmental sensing, signal transduction and metabolic versatility as compared to the epipelagic counterparts is thought to enable the deep-sea bacterioplankton to rapidly adapt to changing environmental conditions associated with resource scarcity and high diversity of energy and carbon substrates in the bathyal biotopes. Together with a versatile heterotrophy, mixotrophy and anaplerosis are thought to enable the deep-sea bacterioplankton to cope with these environmental conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Analysis of composition and structure of coastal to mesopelagic bacterioplankton communities in the northern gulf of Mexico.

    Science.gov (United States)

    King, Gary M; Smith, Conor B; Tolar, Bradley; Hollibaugh, James T

    2012-01-01

    16S rRNA gene amplicons were pyrosequenced to assess bacterioplankton community composition, diversity, and phylogenetic community structure for 17 stations in the northern Gulf of Mexico (nGoM) sampled in March 2010. Statistical analyses showed that samples from depths ≤100 m differed distinctly from deeper samples. SAR 11 α-Proteobacteria and Bacteroidetes dominated communities at depths ≤100 m, which were characterized by high α-Proteobacteria/γ-Proteobacteria ratios (α/γ > 1.7). Thaumarchaeota, Firmicutes, and δ-Proteobacteria were relatively abundant in deeper waters, and α/γ ratios were low (bacterioplankton communities might develop independently of nGoM physical-chemical variables. Phylogenetic community structure as measured by the net relatedness (NRI) and nearest taxon (NTI) indices also did not vary with depth. NRI values indicated that most of the communities were comprised of OTUs more distantly related to each other in whole community comparisons than expected by chance. NTI values derived from phylogenetic distances of the closest neighbor for each OTU in a given community indicated that OTUs tended to occur in clusters to a greater extent than expected by chance. This indicates that "habitat filtering" might play an important role in nGoM bacterioplankton species assembly, and that such filtering occurs throughout the water column.

  3. To Befriend or Not: Naturally Developing Friendships Amongst a Clinical Group of Adolescents with Chronic Pain.

    Science.gov (United States)

    Forgeron, Paula A; MacLaren Chorney, Jill; Carlson, Torie E; Dick, Bruce D; Plante, Erica

    2015-10-01

    Adolescents with chronic pain frequently perceive a lack of support from friends. Support from a peer with a shared experience has been found to provide emotional, informational, and appraisal support. We sought to quantify the frequency with which adolescents with chronic pain want to befriend other adolescents with chronic pain, and to describe the features of these friendships. Adolescents with chronic pain who had attended a 10-week structured self-management program from 3 sites were invited to complete an online survey. Forty teens participated, 95% (n = 38) were girls; 32% (n = 13) befriended another; 52% (n = 21) were interested in befriending another but did not; 15% (n = 6) were not interested in befriending anyone. Over half (62%) of the friendships lasted at least 1 year (n = 8), but only 2 intermingled these with their regular friendships. Pain was discussed frequently during interactions. The most common reasons for not forming friendships were no time to exchange contact information during group and not having things in common. Reasons for not being interested in forming a friendship also included not having anything in common apart from pain. The majority of participants were interested in befriending another. Emotional support, by feeling understood and discussing pain without fear that the other is disinterested, was the main peer support provided. Without common interests, this form of friendship may not last and is at risk for being overly solicitous by focusing on pain. It remains unclear whether the benefits of peer support translate into improved function. Copyright © 2015 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  4. Natural hazards Early career scientist Team (NhET), a newborn group bridging science to a broader community

    Science.gov (United States)

    Lombardo, Luigi; Cigala, Valeria; Rizzi, Jonathan; Craciun, Iulya; Gain, Animesh Kumar; Albano, Raffaele

    2017-04-01

    Alongside with other major EGU divisions, Natural Hazard has recently formed his Early Career Scientist (ECS) team, known as NhET. NhET was born in 2016 and its scope includes various activities for the EGU members, the international scientific community as well as for the general public. We are a group of six early career researchers, either PhDs or Post-Docs, from different fields of Natural Hazard, keen to promote knowledge exchanges and collaborations. This is done by organizing courses, training sessions and social activities, especially targeting ECSs, during the EGU General Assembly for this year and the next to come. Outside the timeframe of the EGU conference, we constantly promote EGU contents for our division. This is done through the division website (http://www.egu.eu/nh), a mailing list (https://groups.google.com/forum/#!forum/nhet) and social media. With respect to the latter, a new Facebook page will be launched shortly and other platforms such as Twitter will be used to reach a broader audience. These platforms will foster the transmission of Natural Hazard topics to anyone who is interested. The main content will be researchers' interviews, information about open positions, trainings, open source software, conferences together with news on hazards and their anthropic and environmental impacts. We are NhET and we invite you all to follow and collaborate with us for a more dynamic, efficient and widespread scientific communication.

  5. Environmental rather than spatial factors structure bacterioplankton communities in shallow lakes along a > 6000 km latitudinal gradient in South America.

    Science.gov (United States)

    Souffreau, Caroline; Van der Gucht, Katleen; van Gremberghe, Ineke; Kosten, Sarian; Lacerot, Gissell; Lobão, Lúcia Meirelles; de Moraes Huszar, Vera Lúcia; Roland, Fabio; Jeppesen, Erik; Vyverman, Wim; De Meester, Luc

    2015-07-01

    Metacommunity studies on lake bacterioplankton indicate the importance of environmental factors in structuring communities. Yet most of these studies cover relatively small spatial scales. We assessed the relative importance of environmental and spatial factors in shaping bacterioplankton communities across a > 6000 km latitudinal range, studying 48 shallow lowland lakes in the tropical, tropicali (isothermal subzone of the tropics) and tundra climate regions of South America using denaturing gradient gel electrophoresis. Bacterioplankton community composition (BCC) differed significantly across regions. Although a large fraction of the variation in BCC remained unexplained, the results supported a consistent significant contribution of local environmental variables and to a lesser extent spatial variables, irrespective of spatial scale. Upon correction for space, mainly biotic environmental factors significantly explained the variation in BCC. The abundance of pelagic cladocerans remained particularly significant, suggesting grazer effects on bacterioplankton communities in the studied lakes. These results confirm that bacterioplankton communities are predominantly structured by environmental factors, even over a large-scale latitudinal gradient (6026 km), and stress the importance of including biotic variables in studies that aim to understand patterns in BCC. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Seasonal variations in bacterioplankton community structures in two small rivers in the Himi region of central Japan and their relationships with environmental factors.

    Science.gov (United States)

    Tanaka, Daisuke; Takahashi, Toyo; Yamashiro, Yoko; Tanaka, Hitoshi; Kimochi, Yuzuru; Nishio, Masaki; Sakatoku, Akihiro; Nakamura, Shogo

    2017-11-13

    The aim of this study was to improve our understanding of seasonal variations and the effects of physicochemical conditions on the bacterioplankton communities in two small rivers, the Moo and Nakayachi Rivers in the Himi region of central Japan. These rivers are inhabited by unionid freshwater mussels, which are used for oviposition by the endangered Itasenpara bitterling (Acheilognathus longipinnis). Water samples were collected every month between March 2011 and February 2012. Changes in bacterioplankton community structures were analysed using an approach that did not require cultivating the bacteria and involved PCR and denaturing gradient gel electrophoresis. The bacterioplankton community structures in the two rivers were similar in all seasons except winter. The bacterial sequences identified were dominated by typical freshwater Actinobacteria, Bacteroidetes, Cyanobacteria, α-Proteobacteria, and β-Proteobacteria bacterioplankton. Many β-Proteobacteria species were detected in all seasons, but Bacteroidetes species were dominant in the winter. The bacterioplankton community structures were affected by biochemical oxygen demand, chemical oxygen demand, chlorophyll-a concentration, water depth, and water temperature. These results provide a foundation for a more detailed understanding of the conditions that provide a suitable unionid habitat.

  7. Submerged macrophytes shape the abundance and diversity of bacterial denitrifiers in bacterioplankton and epiphyton in the Shallow Fresh Lake Taihu, China.

    Science.gov (United States)

    Fan, Zhou; Han, Rui-Ming; Ma, Jie; Wang, Guo-Xiang

    2016-07-01

    nirK and nirS genes are important functional genes involved in the denitrification pathway. Recent studies about these two denitrifying genes are focusing on sediment and wastewater microbe. In this study, we conducted a comparative analysis of the abundance and diversity of denitrifiers in the epiphyton of submerged macrophytes Potamogeton malaianus and Ceratophyllum demersum as well as in bacterioplankton in the shallow fresh lake Taihu, China. Results showed that nirK and nirS genes had significant different niches in epiphyton and bacterioplankton. Bacterioplankton showed greater abundance of nirK gene in terms of copy numbers and lower abundance of nirS gene. Significant difference in the abundance of nirK and nirS genes also existed between the epiphyton from different submerged macrophytes. Similar community diversity yet different community abundance was observed between epiphytic bacteria and bacterioplankton. No apparent seasonal variation was found either in epiphytic bacteria or bacterioplankton; however, environmental parameters seemed to have direct relevancy with nirK and nirS genes. Our study suggested that submerged macrophytes have greater influence than seasonal parameters in shaping the presence and abundance of bacterial denitrifiers. Further investigation needs to focus on the potential contact and relative contribution between denitrifiers and environmental factors.

  8. Habitat filtering of bacterioplankton communities above polymetallic nodule fields and sediments in the Clarion-Clipperton zone of the Pacific Ocean.

    Science.gov (United States)

    Lindh, Markus V; Maillot, Brianne M; Smith, Craig R; Church, Matthew J

    2018-04-01

    Deep-sea mining of commercially valuable polymetallic nodule fields will generate a seabed sediment plume into the water column. Yet, the response of bacterioplankton communities, critical in regulating energy and matter fluxes in marine ecosystems, to such disturbances is unknown. Metacommunity theory, traditionally used in general ecology for macroorganisms, offers mechanistic understanding on the relative role of spatial differences compared with local environmental conditions (habitat filtering) for community assembly. We examined bacterioplankton metacommunities using 16S rRNA amplicons from the Clarion-Clipperton Zone (CCZ) in the eastern Pacific Ocean and in global ocean transect samples to determine sensitivity of these assemblages to environmental perturbations. Habitat filtering was the main assembly mechanism of bacterioplankton community composition in the epi- and mesopelagic waters of the CCZ and the Tara Oceans transect. Bathy- and abyssopelagic bacterioplankton assemblages were mainly assembled by undetermined metacommunity types or neutral and dispersal-driven patch-dynamics for the CCZ and the Malaspina transect. Environmental disturbances may alter the structure of upper-ocean microbial assemblages, with potentially even more substantial, yet unknown, impact on deep-sea communities. Predicting such responses in bacterioplankton assemblage dynamics can improve our understanding of microbially-mediated regulation of ecosystem services in the abyssal seabed likely to be exploited by future deep-sea mining operations. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

  9. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  10. Reducing visitors' group size increases the number of birds during educational activities: Implications for management of nature-based recreation.

    Science.gov (United States)

    Remacha, Carolina; Pérez-Tris, Javier; Delgado, Juan Antonio

    2011-06-01

    Organized tours to watch wildlife are popular recreational and educational activities, in which the visitor expectative (to observe as many and as diverse animals as possible) runs parallel to conservation purposes. However, the presence of visitors may cause negative impacts on wildlife, which makes recreation difficult to manage. Thus, restricting visitor's load to minimize impacts on fauna may be advisable, but too much restriction may end up disappointing the public. We analysed how visitors' group size influences the number and variety of birds observed during an educational activity directed to scholars, in a forested area where public access is otherwise restricted. We observed fewer birds, but not fewer species, as the size of scholars' groups increased. Such effect was apparently mediated by a few species demonstrating reduced tolerance to increased group size. Our results support the idea that reducing the size of visitors' groups not only helps to minimize the negative impacts on wildlife derived from leisure activities, but also allows visitors to watch more wildlife. Therefore, organizing visitors in small numbers is recommended in the design of activities directed to groups of people visiting natural areas. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Systemic lupus erythematosus in three ethnic groups. VI: Factors associated with fatigue within 5 years of criteria diagnosis. LUMINA Study Group. LUpus in MInority populations: NAture vs Nurture.

    Science.gov (United States)

    Zonana-Nacach, A; Roseman, J M; McGwin, G; Friedman, A W; Baethge, B A; Reveille, J D; Alarcón, G S

    2000-01-01

    To determine the frequency, degree and associated features of fatigue among Hispanic (H), African American (AA) and Caucasian (C) patients with recent onset (NAture vs Nurture) cohort were studied. Fatigue [Fatigue Severity Scale (FSS)] was defined as present if FSS score > or = 3.0. Variables from functional, clinical, sociodemographic, health behaviors, behavioral and psychological and immunogenetics domains were ascertained at study entry. Associations were examined using regression models. Eighty-six percent (85.7%) of patients reported having fatigue (82.6% H; 85.5% AA; 88.7% C); median FSS score, 5.3. Factors from the psychological and clinical domains were primarily associated with FSS; immunogenetic (HLA Class II phenotypes) features were not. Increased fatigue was strongly associated with decreasing function, both physical and mental. Variables associated with significantly greater degree of fatigue at baseline in the multivariable stepwise model in order of decreasing additional partial R2 explained included: abnormal illness-related behaviors, older age, higher self-reported pain, greater degree of helplessness, greater disease activity, Caucasian race, and lacking health insurance (model R2 = 37%). Fatigue is one of the most prevalent clinical manifestations of SLE across all ethnic groups. The perception of fatigue severity in SLE may be multifactorial in origin, including psychosocial factors and disease activity. If these prove causal, knowledge of their contribution may suggest therapeutic and/or behavioral interventions, which could ameliorate this pervasive and often incapacitating symptom of SLE.

  12. The natural fenhexamid-resistant grey mould populations from strawberry in Zhejiang Province are dominated by Botrytis cinerea group S.

    Science.gov (United States)

    Yin, Dafang; Wu, Sisi; Liu, Na; Yin, Yanni; Ma, Zhonghua

    2016-08-01

    Recently, a novel clade Botrytis cinerea group S was found to be common in B. cinerea populations from Germany and New Zealand. Fenhexamid, an effective antibotrytis fungicide, has not been registered in China, but our preliminary study detected fenhexamid-resistant (HydR) isolates from strawberry in Zhejiang Province. Genetic identification of 639 B. cinerea isolates from strawberry found that 331 (62.9%) belonged to B. cinerea group S. The frequency of HydR isolates ranged from 0 to 37.5% among the nine locations. Of the 74 HydR isolates, 71 were B. cinerea group S and moderately resistant to fenhexamid (HydR). Seven new mutations S9G, P57A, P269L, V365A, E368D, E375K and A378T in the target gene erg27 were reported for the first time. Sixty-two (83.8%) HydR isolates simultaneously carried P57A and A378T mutations, and further transformation assays showed that integration of one copy of erg27(P57A) (,) (A378T) into a wild-type strain led to partial resistance. Detached fruit studies showed that fenhexamid at the recommended field rate could control the disease incited by moderately resistant isolates but not by highly resistant isolates. B. cinerea group S isolates are widespread in all strawberry-growing locations in Zhejiang Province. The natural HydR populations from strawberry are dominated by B. cinerea group S. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  13. The hidden seasonality of the rare biosphere in coastal marine bacterioplankton

    KAUST Repository

    Alonso-Sáez, Laura

    2015-04-08

    Summary: Rare microbial taxa are increasingly recognized to play key ecological roles, but knowledge of their spatio-temporal dynamics is lacking. In a time-series study in coastal waters, we detected 83 bacterial lineages with significant seasonality, including environmentally relevant taxa where little ecological information was available. For example, Verrucomicrobia had recurrent maxima in summer, while the Flavobacteria NS4, NS5 and NS2b clades had contrasting seasonal niches. Among the seasonal taxa, only 4 were abundant and persistent, 20 cycled between rare and abundant and, remarkably, most of them (59) were always rare (contributing <1% of total reads). We thus demonstrate that seasonal patterns in marine bacterioplankton are largely driven by lineages that never sustain abundant populations. A fewer number of rare taxa (20) also produced episodic \\'blooms\\', and these events were highly synchronized, mostly occurring on a single month. The recurrent seasonal growth and loss of rare bacteria opens new perspectives on the temporal dynamics of the rare biosphere, hitherto mainly characterized by dormancy and episodes of \\'boom and bust\\', as envisioned by the seed-bank hypothesis. The predictable patterns of seasonal reoccurrence are relevant for understanding the ecology of rare bacteria, which may include key players for the functioning of marine ecosystems. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  14. Bacterioplankton community analysis in tilapia ponds by Illumina high-throughput sequencing.

    Science.gov (United States)

    Fan, Li Min; Barry, Kamira; Hu, Geng Dong; Meng, Shun long; Song, Chao; Wu, Wei; Chen, Jia Zhang; Xu, Pao

    2016-01-01

    The changes of microbial community in aquaculture systems under the effects of stocking densities and seasonality were investigated in tilapia ponds. Total DNAs were extracted from the water samples, 16S rRNA gene was amplified and the bacterial community analyzed by Illumina high-throughput sequencing obtaining 3486 OTUs, from a total read of 715,842 sequences. Basing on the analysis of bacterial compositions, richness, diversity, bacterial 16S rRNA gene abundance, water sample comparisons and existence of specific bacterial taxa within three fish ponds in a 4 months period, the study conclusively observed that the dominant phylum in all water samples were similar, and they included; Proteobacteria, Cyanobacteria, Bacteroidetes, Actinobacteria, Planctomycetes and Chlorobi, distributed in different proportions in the different months and ponds. The seasonal changes had a more pronounced effect on the bacterioplankton community than the stocking densities; however some differences between the ponds were more likely caused by feed coefficient than by stocking densities. At the same time, most bacterial communities were affected by the nutrient input except phylum Cyanobacteria that was also affected by the feed control of tilapia.

  15. Macrophyte Species Drive the Variation of Bacterioplankton Community Composition in a Shallow Freshwater Lake

    Science.gov (United States)

    Zeng, Jin; Bian, Yuanqi; Xing, Peng

    2012-01-01

    Macrophytes play an important role in structuring aquatic ecosystems. In this study, we explored whether macrophyte species are involved in determining the bacterioplankton community composition (BCC) in shallow freshwater lakes. The BCC in field areas dominated by different macrophyte species in Taihu Lake, a large, shallow freshwater lake, was investigated over a 1-year period. Subsequently, microcosm experiments were conducted to determine if single species of different types of macrophytes in an isolated environment would alter the BCC. Denaturing gradient gel electrophoresis (DGGE), followed by cloning and sequence analysis of selected samples, was employed to analyze the BCC. The DGGE results of the field investigations indicated that the BCC changed significantly from season to season and that the presence of different macrophyte species resulted in lower BCC similarities in the summer and fall. LIBSHUFF analysis of selected clone libraries from the summer demonstrated different BCCs in the water column surrounding different macrophytes. Relative to the field observations, the microcosm studies indicated that the BCC differed more pronouncedly when associated with different species of macrophytes, which was also supported by LIBSHUFF analysis of the selected clone libraries. Overall, this study suggested that macrophyte species might be an important factor in determining the composition of bacterial communities in this shallow freshwater lake and that the species-specific influence of macrophytes on BCC is variable with the season and distance. PMID:22038598

  16. Jellyfish-associated bacterial communities and bacterioplankton in Indonesian Marine lakes.

    Science.gov (United States)

    Cleary, Daniel F R; Becking, Leontine E; Polónia, Ana R M; Freitas, Rossana M; Gomes, Newton C M

    2016-05-01

    In the present study, we compared communities of bacteria in two jellyfish species (the 'golden' jellyfish Mastigias cf.papua and the box jellyfish Tripedalia cf.cystophora) and water in three marine lakes located in the Berau region of northeastern Borneo, Indonesia. Jellyfish-associated bacterial communities were compositionally distinct and less diverse than bacterioplankton communities. Alphaproteobacteria, Gammaproteobacteria, Synechococcophycidae and Flavobacteriia were the most abundant classes in water. Jellyfish-associated bacterial communities were dominated by OTUs assigned to the Gammaproteobacteria (family Endozoicimonaceae), Mollicutes, Spirochaetes and Alphaproteobacteria (orders Kiloniellales and Rhodobacterales). Mollicutes were mainly restricted to Mastigias whereas Spirochaetes and the order Kiloniellales were most abundant in Tripedalia hosts. The most abundant OTU overall in jellyfish hosts was assigned to the family Endozoicimonaceae and was highly similar to organisms in Genbank obtained from various hosts including an octocoral, bivalve and fish species. Other abundant OTUs included an OTU assigned to the order Entomoplasmatales and mainly found in Mastigias hosts and OTUs assigned to the Spirochaetes and order Kiloniellales and mainly found in Tripedalia hosts. The low sequence similarity of the Entomoplasmatales OTU to sequences in Genbank suggests that it may be a novel lineage inhabiting Mastigias and possibly restricted to marine lakes. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Seasonal dynamics of the littoral zooplankton groups of the Uday River within the National Nature Park "Pyryatynsky"

    Directory of Open Access Journals (Sweden)

    Z. V. Burian

    2017-08-01

    Full Text Available The increase in anthropogenic impact on aquatic ecosystems causes significant alterations in the composition and structure of hydrobiont groups. These processes are characteristic of the hydrobiocenoses of the Uday River, the valley of which lies within the National Nature Park "Pyryatynsky", established in 2009 in the Pyryatyn district of Poltava region. Within this protected area it is convenient to carry out continuous monitoring of changes in anthropogenic load on shore ecosystems of the river. One of the most convenient monitoring groups is zooplankton, which is one of the essential components of the trophic networks of aquatic ecosystems and which is the feeding basis of planktonophagous and young fish. The object of this research was the major groups of zooplankton: rotifers (class Eurotatoria, cladocerans (class Branchiopoda, order Cladocera, different age stages of copepods (class Copepoda, ostracods (class Ostracoda. Zooplankton were collected in the daytime in spring (mid April, summer (end of July and autumn (late September 2016 within eight research stations. As a result of the conducted research, 69 species of zooplankton were registered within the littoral water area of the Uday River. Monogonont rotifers numbered 19 (27.5% species, bdelloid rotifers (subclass Bdelloidea, cladocerans – 33 (47.9% species, copepods – 17 (24.6%. According to the faunal spectrum in the zooplankton groups, representatives of the cladoceran complex predominated. This is due to the favourable conditions for the development of filtrators, of which a considerable part is cladocerans. Three species of rotifers were identified in Poltava region for the first time: Beauchampiella eudactylota (Gosse, 1886, Dipleuchlanis propatula (Gosse, 1886, Mytilina acanthophora (Hauer, 1938. During the spring, 33 species of zooplankton were collected: rotifers – 10 species, cladocerans – 14, copepods – 9 species. In summer 41 species were registered, including

  18. Clean fossil or refuse dump. Results of focus groups with citizens on CO2-storage in depleted natural gas fields

    International Nuclear Information System (INIS)

    Ganzevles, J.H.; Kets, A.; Van Est, Q.C.

    2008-09-01

    This report gives an account of a meeting with four focus groups - 31 citizens in Total - held at the Rathenau Institute on 7 July 2007. Carbon capture and storage (CCS) in depleted natural gas fields was the main topic. The goal of this meeting was to explore the public opinion on CCS, to gauge their attitude towards new technology and to examine the influence of information services on their opinion. The analysis has resulted in a comprehensive overview of arguments in favor of and against the development of CO2 capture and storage in the Netherlands. The study illustrates how all questions and points of interest can be classified based on three different angles, i.e. (1) the promise of CCS as instrument for handling environmental problems, energy problems and offering economic opportunities for the Netherlands; (2) the implementation process of CCS; and (3) possible side effects of CCS. [mk] [nl

  19. Seasonal variation of the main zooplanktonic groups of the protected natural area estuary El Salado, Jalisco, Mexico

    Directory of Open Access Journals (Sweden)

    Navarro-Rodríguez, M.C.

    2015-01-01

    Full Text Available Estuarine systems are the most important aquatic natural resources of the nation from various perspectives; fisheries use them mainly through studies that allow the detection and evaluation of the areas of concentration of adults on reproduction phase and potentially exploitable species. This present paper analyzes the spatial and temporal variation of the abundance of zooplankton groups in the Estuary El Salado, Puerto Vallarta, Jalisco. Eight zooplanktonic trawls were conducted during diurnal periods from spring to winter 2001, trawls were superficial, lasting ten minutes, by using a standard “Zeppelin” net with a mesh size of 505 μm with a length of 1.50 m mouth width of 0.60 m which was equipped with a digital flow meter to calculate the volume of filtered water, abundance data were normalized to a volume of 1000 m3. The total catch was 101,968.4 organisms, represented in eleven groups, the brachyurans were the most important group in the order of abundance accounting for 44.5 %, followed by 24.1 % in chaetognaths, decapod with 6.78 %, euphausiids with 11.84 %, and less abundant copepods with 6.18 %, 3.37 % siphonophores small jellyfish, stomatopods 2.83 %, 0.22 % amphipods, cladocerans with 0.33 %, 0.08 % gastropods and finally rare organisms with 0.02 % (appendicular, polychaetes and cumaceans. Variations in both spatial and temporal abundance were influenced by tidal conditions as well as variations in temperature and salinity. All registered major zooplankton groups abundances were homogeneous in the four seasonal periods, however spring was characterized by low abundance, while for summer and winter, the highest values recorded were represented mainly by the Brachyura order, and those abundances were associated with two reproductive periods in both seasons.

  20. Polymorphism of CRISPR shows separated natural groupings of Shigella subtypes and evidence of horizontal transfer of CRISPR.

    Science.gov (United States)

    Yang, Chaojie; Li, Peng; Su, Wenli; Li, Hao; Liu, Hongbo; Yang, Guang; Xie, Jing; Yi, Shengjie; Wang, Jian; Cui, Xianyan; Wu, Zhihao; Wang, Ligui; Hao, Rongzhang; Jia, Leili; Qiu, Shaofu; Song, Hongbin

    2015-01-01

    Clustered, regularly interspaced, short palindromic repeats (CRISPR) act as an adaptive RNA-mediated immune mechanism in bacteria. They can also be used for identification and evolutionary studies based on polymorphisms within the CRISPR locus. We amplified and analyzed 6 CRISPR loci from 237 Shigella strains belonging to the 4 species groups, as well as 13 Escherichia coli strains. The CRISPR-associated (cas) gene sequence arrays of these strains were screened and compared. The CRISPR sequences from Shigella were conserved among subtypes, suggesting that CRISPR may represent a new identification tool for the detection and discrimination of Shigella species. Secondary structure analysis showed a different stem-loop structure at the terminal repeat, suggesting a distinct recognition mechanism in the formation of crRNA. In addition, the presence of "self-target" spacers and polymorphisms within CRISPR in Shigella indicated a selective pressure for inhibition of this system, which has the potential to damage "self DNA." Homology analysis of spacers showed that CRISPR might be involved in the regulation of virulence transmission. Phylogenetic analysis based on CRISPR sequences from Shigella and E. coli indicated that although phenotypic properties maintain convergent evolution, the 4 Shigella species do not represent natural groupings. Surprisingly, comparative analysis of Shigella repeats with other species provided new evidence for CRISPR horizontal transfer. Our results suggested that CRISPR analysis is applicable for the detection of Shigella species and for investigation of evolutionary relationships.

  1. Polymorphism of CRISPR shows separated natural groupings of Shigella subtypes and evidence of horizontal transfer of CRISPR

    Science.gov (United States)

    Yang, Chaojie; Li, Peng; Su, Wenli; Li, Hao; Liu, Hongbo; Yang, Guang; Xie, Jing; Yi, Shengjie; Wang, Jian; Cui, Xianyan; Wu, Zhihao; Wang, Ligui; Hao, Rongzhang; Jia, Leili; Qiu, Shaofu; Song, Hongbin

    2015-01-01

    Clustered, regularly interspaced, short palindromic repeats (CRISPR) act as an adaptive RNA-mediated immune mechanism in bacteria. They can also be used for identification and evolutionary studies based on polymorphisms within the CRISPR locus. We amplified and analyzed 6 CRISPR loci from 237 Shigella strains belonging to the 4 species groups, as well as 13 Escherichia coli strains. The CRISPR-associated (cas) gene sequence arrays of these strains were screened and compared. The CRISPR sequences from Shigella were conserved among subtypes, suggesting that CRISPR may represent a new identification tool for the detection and discrimination of Shigella species. Secondary structure analysis showed a different stem-loop structure at the terminal repeat, suggesting a distinct recognition mechanism in the formation of crRNA. In addition, the presence of “self-target” spacers and polymorphisms within CRISPR in Shigella indicated a selective pressure for inhibition of this system, which has the potential to damage “self DNA.” Homology analysis of spacers showed that CRISPR might be involved in the regulation of virulence transmission. Phylogenetic analysis based on CRISPR sequences from Shigella and E. coli indicated that although phenotypic properties maintain convergent evolution, the 4 Shigella species do not represent natural groupings. Surprisingly, comparative analysis of Shigella repeats with other species provided new evidence for CRISPR horizontal transfer. Our results suggested that CRISPR analysis is applicable for the detection of Shigella species and for investigation of evolutionary relationships. PMID:26327282

  2. Grazer and virus-induced mortality of bacterioplankton accelerates development of .i.Flectobacillus./i. populations in a freshwater community

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Weinbauer, M.G.; Horňák, Karel; Jezbera, Jan; Nedoma, Jiří; Dolan, J. R.

    2007-01-01

    Roč. 9, č. 3 (2007), s. 789-800 ISSN 1462-2912 R&D Projects: GA ČR(CZ) GA206/05/0007; GA AV ČR(CZ) 1QS600170504 Grant - others:MŠMT(CZ) Barrande 2004-004-2 Institutional research plan: CEZ:AV0Z60170517 Source of funding: V - iné verejné zdroje Keywords : bacterioplankton community composition * virus lysis * flagellate bacterivory * reservoir * FISH analysis of food vacuoles * microautoradiography Subject RIV: EE - Microbiology, Virology Impact factor: 4.929, year: 2007

  3. Natural Arsenic in the Miocene Hawthorn Group, Florida: Wide Ranging Implications for ASR, Phosphate Mining, Private Well

    Science.gov (United States)

    Lazareva, O. V.; Pichler, T.

    2004-12-01

    organic material, clays, and iron oxides contain lower As concentrations contrasted to pyrite; (5) Pyrite occurs in framboidal and euhedral forms. Because phosphorous, arsenic and sulfur are chemically closely related, they often occur together in nature, thus posing a potential problem for the phosphate industry. There have been several occurrences of swine fatalities due to arsenic poisoning as a result of phosphate feed supplements. Information about the concentration, distribution and mineralogical association of naturally occurring As is important, because this is a first step to forecast its behavior during anthropogenic induced physico-chemical changes in the aquifer. Recently, aquifer storage and recovery (ASR) facilities in central Florida reported As concentrations in excess of 100 μ g/L in recovered water. The ASR storage zone is the Suwannee Limestone, which directly underlies the Hawthorn sediments. It is crucial to the future of ASR in this area to understand the source and distribution of arsenic in the overlying Hawthorn Group and the cycling of arsenic in the Florida platform.

  4. Bacterioplankton features and its relations with doc characteristics and other limnological variables in Paraná river floodplain environments (PR/MS-Brazil).

    Science.gov (United States)

    Teixeira, Mariana Carolina; Santana, Natália Fernanda; de Azevedo, Júlio César Rodrigues; Pagioro, Thomaz Aurélio

    2011-07-01

    Since the introduction of the Microbial Loop concept, many studies aimed to explain the role of bacterioplankton and dissolved organic carbon (DOC) in aquatic ecosystems. Paraná River floodplain system is a very complex environment where these subjects were little explored. The aim of this work was to characterize bacterial community in terms of density, biomass and biovolume in some water bodies of this floodplain and to verify its temporal variation and its relation with some limnological variables, including some indicators of DOC quality, obtained through Ultraviolet-visible (UV-VIS) and fluorescence spectroscopic analysis. Bacterial density, biomass and biovolume are similar to those from other freshwater environments and both density and biomass were higher in the period with less rain. The limnological and spectroscopic features that showed any relation with bacterioplankton were the concentrations of N-NH4 and P-PO4, water transparency, and some indicators of DOC quality and origin. The analysis of these relations showed a possible competition between bacterioplankton and phytoplankton for inorganic nutrients and that the DOC used by bacterioplankton is labile and probably from aquatic macrophytes.

  5. Bacterioplankton features and its relations with doc characteristics and other limnological variables in Paraná river floodplain environments (PR/MS-Brazil

    Directory of Open Access Journals (Sweden)

    Mariana Carolina Teixeira

    2011-09-01

    Full Text Available Since the introduction of the Microbial Loop concept, many studies aimed to explain the role of bacterioplankton and dissolved organic carbon (DOC in aquatic ecosystems. Paraná River floodplain system is a very complex environment where these subjects were little explored. The aim of this work was to characterize bacterial community in terms of density, biomass and biovolume in some water bodies of this floodplain and to verify its temporal variation and its relation with some limnological variables, including some indicators of DOC quality, obtained through Ultraviolet-visible (UV-VIS and fluorescence spectroscopic analysis. Bacterial density, biomass and biovolume are similar to those from other freshwater environments and both density and biomass were higher in the period with less rain. The limnological and spectroscopic features that showed any relation with bacterioplankton were the concentrations of N-NH4 and P-PO4, water transparency, and some indicators of DOC quality and origin. The analysis of these relations showed a possible competition between bacterioplankton and phytoplankton for inorganic nutrients and that the DOC used by bacterioplankton is labile and probably from aquatic macrophytes.

  6. Nitrogen and carbon limitation of planktonic primary production and phytoplankton-bacterioplankton coupling in ponds on the McMurdo Ice Shelf, Antarctica

    DEFF Research Database (Denmark)

    Sorrell, B.K.; Hawes, I.; Safi, K.

    2013-01-01

    -limited phytoplanton photosynthesis in some waters. Phytoplankton and bacterioplankton production were extremely closely linked, with no indication of any external nutrient inputs. Most of the large amounts of DOC and DON in the ponds was recalcitrant and not available to plankton. In meromictically stratified ponds...

  7. Effects of decreased resource availability, protozoan grazing and viral impact on a structure of bacterioplankton assemblage in a canyon-shaped reservoir

    Czech Academy of Sciences Publication Activity Database

    Horňák, Karel; Mašín, Michal; Jezbera, Jan; Bettarel, Y.; Nedoma, Jiří; Sime-Ngando, T.; Šimek, Karel

    2005-01-01

    Roč. 52, č. 3 (2005), s. 315-327 ISSN 0168-6496 R&D Projects: GA ČR(CZ) GA206/02/0003 Grant - others:PICS(FR) project 1111 Institutional research plan: CEZ:AV0Z60170517 Keywords : bacterioplankton * protozoan grazing * viral lysis Subject RIV: EH - Ecology, Behaviour Impact factor: 2.787, year: 2005

  8. Linking phytoplankton and bacterioplankton community dynamics to iron-binding ligand production in a microcosm experiment

    Science.gov (United States)

    Hogle, S. L.; Bundy, R.; Barbeau, K.

    2016-02-01

    Several significant lines of evidence implicate heterotrophic bacterioplankton as agents of iron cycling and sources of iron-binding ligands in seawater, but direct and mechanistic linkages have mostly remained elusive. Currently, it is unknown how microbial community composition varies during the course of biogenic particle remineralization and how shifts in community structure are related to sources and sinks of Fe-binding ligands. In order to simulate the rise, decline, and ultimate remineralization of a phytoplankton bloom, we followed the production of different classes of Fe-binding ligands as measured by electrochemical techniques, Fe concentrations, and macronutrient concentrations in a series of iron-amended whole seawater incubations over a period of six days during a California Current Ecosystem Long Term Ecological Research (CCE-LTER) process cruise. At the termination of the experiment phytoplankton communities were similar across iron treatments, but high iron conditions generated greater phytoplankton biomass and increased nutrient drawdown suggesting that phytoplankton communities were in different phases of bloom development. Strikingly, L1 ligands akin to siderophores in binding strength were only observed in high iron treatments implicating phytoplankton bloom phase as an important control. Using high-throughput 16S rRNA gene surveys, we observed that the abundance of transiently dominant copiotroph bacteria were strongly correlated with L1 concentrations. However, incubations with similar L1 concentrations and binding strengths produced distinct copiotroph community profiles dominated by a few strains. We suggest that phytoplankton bloom maturity influences algal-associated heterotrophic community succession, and that L1 production is either directly or indirectly tied to the appearance and eventual dominance of rarely abundant copiotroph bacterial strains.

  9. Temporal and Vertical Distributions of Bacterioplankton at the Gray's Reef National Marine Sanctuary

    Science.gov (United States)

    Lu, Xinxin; Sun, Shulei; Zhang, Yu-Qin; Hollibaugh, James T.

    2014-01-01

    Large spatial scales and long-term shifts of bacterial community composition (BCC) in the open ocean can often be reliably predicted based on the dynamics of physical-chemical variables. The power of abiotic factors in shaping BCC on shorter time scales in shallow estuarine mixing zones is less clear. We examined the diurnal variation in BCC at different water depths in the spring and fall of 2011 at a station in the Gray's Reef National Marine Sanctuary (GRNMS). This site is located in the transition zone between the estuarine plume and continental shelf waters of the South Atlantic Bight. A total of 234,516 pyrotag sequences of bacterial 16S rRNA genes were recovered; they were taxonomically affiliated with >200 families of 23 bacterial phyla. Nonmetric multidimensional scaling analysis revealed significant differences in BCC between spring and fall samples, likely due to seasonality in the concentrations of dissolved organic carbon and nitrate plus nitrite. Within each diurnal sampling, BCC differed significantly by depth only in the spring and differed significantly between day and night only in the fall. The former variation largely tracked changes in light availability, while the latter was most correlated with concentrations of polyamines and chlorophyll a. Our results suggest that at the GRNMS, a coastal mixing zone, diurnal variation in BCC is attributable to the mixing of local and imported bacterioplankton rather than to bacterial growth in response to environmental changes. Our results also indicate that, like members of the Roseobacter clade, SAR11 bacteria may play an important role in processing dissolved organic material in coastal oceans. PMID:25416764

  10. New insights on resource stoichiometry: assessing availability of carbon, nitrogen, and phosphorus to bacterioplankton

    Science.gov (United States)

    Soares, Ana R. A.; Bergström, Ann-Kristin; Sponseller, Ryan A.; Moberg, Joanna M.; Giesler, Reiner; Kritzberg, Emma S.; Jansson, Mats; Berggren, Martin

    2017-03-01

    Boreal lake and river ecosystems receive large quantities of organic nutrients and carbon (C) from their catchments. How bacterioplankton respond to these inputs is not well understood, in part because we base our understanding and predictions on total pools, yet we know little about the stoichiometry of bioavailable elements within organic matter. We designed bioassays with the purpose of exhausting the pools of readily bioavailable dissolved organic carbon (BDOC), bioavailable dissolved nitrogen (BDN), and bioavailable dissolved phosphorus (BDP) as fast as possible. Applying the method in four boreal lakes at base-flow conditions yielded concentrations of bioavailable resources in the range 105-693 µg C L-1 for BDOC (2 % of initial total DOC), 24-288 µg N L-1 for BDN (31 % of initial total dissolved nitrogen), and 0.2-17 µg P L-1 for BDP (49 % of initial total dissolved phosphorus). Thus, relative bioavailability increased from carbon (C) to nitrogen (N) to phosphorus (P). We show that the main fraction of bioavailable nutrients is organic, representing 80 % of BDN and 61 % of BDP. In addition, we demonstrate that total C : N and C : P ratios are as much as 13-fold higher than C : N and C : P ratios for bioavailable resource fractions. Further, by applying additional bioavailability measurements to seven widely distributed rivers, we provide support for a general pattern of relatively high bioavailability of P and N in relation to C. Altogether, our findings underscore the poor availability of C for support of bacterial metabolism in boreal C-rich freshwaters, and suggest that these ecosystems are very sensitive to increased input of bioavailable DOC.

  11. Bacterioplankton Biogeography of the Atlantic Ocean: A Case Study of the Distance-Decay Relationship.

    Science.gov (United States)

    Milici, Mathias; Tomasch, Jürgen; Wos-Oxley, Melissa L; Decelle, Johan; Jáuregui, Ruy; Wang, Hui; Deng, Zhi-Luo; Plumeier, Iris; Giebel, Helge-Ansgar; Badewien, Thomas H; Wurst, Mascha; Pieper, Dietmar H; Simon, Meinhard; Wagner-Döbler, Irene

    2016-01-01

    In order to determine the influence of geographical distance, depth, and Longhurstian province on bacterial community composition and compare it with the composition of photosynthetic micro-eukaryote communities, 382 samples from a depth-resolved latitudinal transect (51°S-47°N) from the epipelagic zone of the Atlantic ocean were analyzed by Illumina amplicon sequencing. In the upper 100 m of the ocean, community similarity decreased toward the equator for 6000 km, but subsequently increased again, reaching similarity values of 40-60% for samples that were separated by ~12,000 km, resulting in a U-shaped distance-decay curve. We conclude that adaptation to local conditions can override the linear distance-decay relationship in the upper epipelagial of the Atlantic Ocean which is apparently not restrained by barriers to dispersal, since the same taxa were shared between the most distant communities. The six Longhurstian provinces covered by the transect were comprised of distinct microbial communities; ~30% of variation in community composition could be explained by province. Bacterial communities belonging to the deeper layer of the epipelagic zone (140-200 m) lacked a distance-decay relationship altogether and showed little provincialism. Interestingly, those biogeographical patterns were consistently found for bacteria from three different size fractions of the plankton with different taxonomic composition, indicating conserved underlying mechanisms. Analysis of the chloroplast 16S rRNA gene sequences revealed that phytoplankton composition was strongly correlated with both free-living and particle associated bacterial community composition (R between 0.51 and 0.62, p bacterioplankton, most likely because dispersal and evolution occur at drastically different rates in bacteria.

  12. Propionibacterium acnes overabundance and natural killer group 2 member D system activation in corpus-dominant lymphocytic gastritis.

    Science.gov (United States)

    Montalban-Arques, Ana; Wurm, Philipp; Trajanoski, Slave; Schauer, Silvia; Kienesberger, Sabine; Halwachs, Bettina; Högenauer, Christoph; Langner, Cord; Gorkiewicz, Gregor

    2016-12-01

    Corpus-dominant lymphocytic gastritis (LyG) is characterized by CD8 + T-cell infiltration of the stomach epithelium by a so far uncharacterized mechanism. Although Helicobacter pylori is typically undetectable in LyG, patients respond to H. pylori antibiotic eradication therapy, suggesting a non-H. pylori microbial trigger for the disease. Comparative microbiota analysis of specimens from LyG, H. pylori gastritis and healthy controls precluded involvement of H. pylori in LyG but identified Propionibacterium acnes as a possible disease trigger. In addition, the natural killer group 2 member D (NKG2D) system and the proinflammatory cytokine interleukin (IL)-15 are significantly upregulated in the gastric mucosa of LyG patients, and gastric epithelial cells respond to microbe-derived stimuli, including live P. acnes and the microbial products short-chain fatty acids, with induction of NKG2D ligands. In contrast, H. pylori infection does not activate or even repress NKG2D ligands. Together, our findings identify P. acnes as a possible causative agent for LyG, which is dependent on the NKG2D system and IL-15 activation. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

  13. Assessment of various natural orbitals as the basis of large active space density-matrix renormalization group calculations.

    Science.gov (United States)

    Ma, Yingjin; Ma, Haibo

    2013-06-14

    It is well-known that not only the orbital ordering but also the choice of the orbitals itself as the basis may significantly influence the computational efficiency of density-matrix renormalization group (DMRG) calculations. In this study, for assessing the efficiency of using various natural orbitals (NOs) as the DMRG basis, we performed benchmark DMRG calculations with different bases, which included the NOs obtained by various traditional electron correlation methods, as well as NOs acquired from preliminary moderate DMRG calculations (e.g., preserved states less than 500). The tested systems included N2, transition metal Cr2 systems, as well as 1D hydrogen polyradical chain systems under equilibrium and dissociation conditions and 2D hydrogen aggregates. The results indicate that a good compromise between the requirement for low computational costs of acquiring NOs and the demand for high efficiency of NOs as the basis of DMRG calculations may be very dependent on the studied systems' diverse electron correlation characteristics and the size of the active space. It is also shown that a DMRG-complete active space configuration interaction (DMRG-CASCI) calculation in a basis of carefully chosen NOs can provide a less expensive alternative to the standard DMRG-complete active space self-consistent field (DMRG-CASSCF) calculation and avoid the convergence difficulties of orbital optimization for large active spaces. The effect of different NO ordering schemes on DMRG-CASCI calculations is also discussed.

  14. Freshwater bacterioplankton richness in oligotrophic lakes depends on nutrient availability rather than on species-area relationships.

    Science.gov (United States)

    Logue, Jürg Brendan; Langenheder, Silke; Andersson, Anders F; Bertilsson, Stefan; Drakare, Stina; Lanzén, Anders; Lindström, Eva S

    2012-06-01

    A central goal in ecology is to grasp the mechanisms that underlie and maintain biodiversity and patterns in its spatial distribution can provide clues about those mechanisms. Here, we investigated what might determine the bacterioplankton richness (BR) in lakes by means of 454 pyrosequencing of the 16S rRNA gene. We further provide a BR estimate based upon a sampling depth and accuracy, which, to our knowledge, are unsurpassed for freshwater bacterioplankton communities. Our examination of 22,669 sequences per lake showed that freshwater BR in fourteen nutrient-poor lakes was positively influenced by nutrient availability. Our study is, thus, consistent with the finding that the supply of available nutrients is a major driver of species richness; a pattern that may well be universally valid to the world of both micro- and macro-organisms. We, furthermore, observed that BR increased with elevated landscape position, most likely as a consequence of differences in nutrient availability. Finally, BR decreased with increasing lake and catchment area that is negative species-area relationships (SARs) were recorded; a finding that re-opens the debate about whether positive SARs can indeed be found in the microbial world and whether positive SARs can in fact be pronounced as one of the few 'laws' in ecology.

  15. Near-Bottom Hypoxia Impacts Dynamics of Bacterioplankton Assemblage throughout Water Column of the Gulf of Finland (Baltic Sea)

    Science.gov (United States)

    Laas, Peeter; Šatova, Elina; Lips, Inga; Lips, Urmas; Simm, Jaak; Kisand, Veljo; Metsis, Madis

    2016-01-01

    Over the past century the spread of hypoxia in the Baltic Sea has been drastic, reaching its ‘arm’ into the easternmost sub-basin, the Gulf of Finland. The hydrographic and climatological properties of the gulf offer a broad suite of discrete niches for microbial communities. The current study explores spatiotemporal dynamics of bacterioplankton community in the Gulf of Finland using massively parallel sequencing of 16S rRNA fragments obtained by amplifying community DNA from spring to autumn period. The presence of redoxcline and drastic seasonal changes make spatiotemporal dynamics of bacterioplankton community composition (BCC) and abundances in such estuary remarkably complex. To the best of our knowledge, this is the first study that analyses spatiotemporal dynamics of BCC in relation to phytoplankton bloom throughout the water column (and redoxcline), not only at the surface layer. We conclude that capability to survive (or benefit from) shifts between oxic and hypoxic conditions is vital adaptation for bacteria to thrive in such environments. Our results contribute to the understanding of emerging patterns in BCCs that occupy hydrographically similar estuaries dispersed all over the world, and we suggest the presence of a global redox- and salinity-driven metacommunity. These results have important implications for understanding long-term ecological and biogeochemical impacts of hypoxia expansion in the Baltic Sea (and similar ecosystems), as well as global biogeography of bacteria specialized inhabiting similar ecosystems. PMID:27213812

  16. Freshwater bacterioplankton richness in oligotrophic lakes depends on nutrient availability rather than on species–area relationships

    Science.gov (United States)

    Logue, Jürg Brendan; Langenheder, Silke; Andersson, Anders F; Bertilsson, Stefan; Drakare, Stina; Lanzén, Anders; Lindström, Eva S

    2012-01-01

    A central goal in ecology is to grasp the mechanisms that underlie and maintain biodiversity and patterns in its spatial distribution can provide clues about those mechanisms. Here, we investigated what might determine the bacterioplankton richness (BR) in lakes by means of 454 pyrosequencing of the 16S rRNA gene. We further provide a BR estimate based upon a sampling depth and accuracy, which, to our knowledge, are unsurpassed for freshwater bacterioplankton communities. Our examination of 22 669 sequences per lake showed that freshwater BR in fourteen nutrient-poor lakes was positively influenced by nutrient availability. Our study is, thus, consistent with the finding that the supply of available nutrients is a major driver of species richness; a pattern that may well be universally valid to the world of both micro- and macro-organisms. We, furthermore, observed that BR increased with elevated landscape position, most likely as a consequence of differences in nutrient availability. Finally, BR decreased with increasing lake and catchment area that is negative species–area relationships (SARs) were recorded; a finding that re-opens the debate about whether positive SARs can indeed be found in the microbial world and whether positive SARs can in fact be pronounced as one of the few ‘laws' in ecology. PMID:22170419

  17. Virio- and bacterioplankton in the estuary zone of the Ob River and adjacent regions of the Kara Sea shelf

    Science.gov (United States)

    Kopylov, A. I.; Sazhin, A. F.; Zabotkina, E. A.; Romanenko, A. V.; Romanova, N. D.

    2017-01-01

    The distribution of structural and functional characteristics of virioplankton in the north of the Ob River estuary and the adjacent Kara Sea shelf (between latitudes 71°44'44″ N and 73°45'24″ N) was studied with consideration of the spatial variations in the number ( N B) and productivity ( P B) of bacteria and water properties (temperature, salinity, density) by analyzing samples taken in September 2013. The number of plankton viruses ( N V), the occurrence of visible infected bacteria cells, virus-induced mortality of bacteria, and virioplankton production in the studied region varied within (214-2917) × 103 particles/mL, 0.3-5.6% of NB, 2.2-64.4% of P B, and (6-17248) × 103 particles/(mL day), respectively. These parameters were the highest in water layers with a temperature of +7.3-7.5°C, salinity of 3.75-5.41 psu, and conventional density (στ) of 2.846-4.144. The number of bacterioplankton was (614-822) × 103 cells/mL, and the N V/ N B ratio was 1.1-4.5. A large amount of virus particles were attached to bacterial cells and suspended matter. The data testify to the considerable role of viruses in controlling the number and production of heterotrophic bacterioplankton in the interaction zone of river and sea waters.

  18. Seasonality in molecular and cytometric diversity of marine bacterioplankton: the reshuffling of bacterial taxa by vertical mixing

    KAUST Repository

    García, Francisca C.

    2015-07-17

    The ’cytometric diversity’ of phytoplankton communities has been studied based on single-cell properties, but the applicability of this method to characterize bacterioplankton has been unexplored. Here, we analysed seasonal changes in cytometric diversity of marine bacterioplankton along a decadal time-series at three coastal stations in the Southern Bay of Biscay. Shannon-Weaver diversity estimates and Bray-Curtis similarities obtained by cytometric and molecular (16S rRNA tag sequencing) methods were significantly correlated in samples from a 3.5-year monthly time-series. Both methods showed a consistent cyclical pattern in the diversity of surface bacterial communities with maximal values in winter. The analysis of the highly resolved flow cytometry time-series across the vertical profile showed that water column mixing was a key factor explaining the seasonal changes in bacterial composition and the winter increase in bacterial diversity in coastal surface waters. Due to its low cost and short processing time as compared to genetic methods, the cytometric diversity approach represents a useful complementary tool in the macroecology of aquatic microbes.

  19. Complementary Metaproteomic Approaches to Assess the Bacterioplankton Response toward a Phytoplankton Spring Bloom in the Southern North Sea.

    Science.gov (United States)

    Wöhlbrand, Lars; Wemheuer, Bernd; Feenders, Christoph; Ruppersberg, Hanna S; Hinrichs, Christina; Blasius, Bernd; Daniel, Rolf; Rabus, Ralf

    2017-01-01

    Annually recurring phytoplankton spring blooms are characteristic of temperate coastal shelf seas. During these blooms, environmental conditions, including nutrient availability, differ considerably from non-bloom conditions, affecting the entire ecosystem including the bacterioplankton. Accordingly, the emerging ecological niches during bloom transition are occupied by different bacterial populations, with Roseobacter RCA cluster and SAR92 clade members exhibiting high metabolic activity during bloom events. In this study, the functional response of the ambient bacterial community toward a Phaeocystis globosa bloom in the southern North Sea was studied using metaproteomic approaches. In contrast to other metaproteomic studies of marine bacterial communities, this is the first study comparing two different cell lysis and protein preparation methods [using trifluoroethanol (TFE) and in-solution digest as well as bead beating and SDS-based solubilization and in-gel digest (BB GeLC)]. In addition, two different mass spectrometric techniques (ESI-iontrap MS and MALDI-TOF MS) were used for peptide analysis. A total of 585 different proteins were identified, 296 of which were only detected using the TFE and 191 by the BB GeLC method, demonstrating the complementarity of these sample preparation methods. Furthermore, 158 proteins of the TFE cell lysis samples were exclusively detected by ESI-iontrap MS while 105 were only detected using MALDI-TOF MS, underpinning the value of using two different ionization and mass analysis methods. Notably, 12% of the detected proteins represent predicted integral membrane proteins, including the difficult to detect rhodopsin, indicating a considerable coverage of membrane proteins by this approach. This comprehensive approach verified previous metaproteomic studies of marine bacterioplankton, e.g., detection of many transport-related proteins (17% of the detected proteins). In addition, new insights into e.g., carbon and nitrogen

  20. MSW Foundation Students in the Field: Reflections on the Nature and Quality of Group Work Assignments and Supervision

    Science.gov (United States)

    LaPorte, Heidi Heft; Sweifach, Jay

    2011-01-01

    Commentators find that education in social group work has diminished over the past three decades, creating a shortage in group work-trained field instructors. The role of instructing group work students may appear relatively easy; however, quality instruction requires careful planning, time, energy, and specialized knowledge. Without knowledge and…

  1. Group velocity dispersion measurement method using sinusoidally phase-modulated continuous wave light based on cyclic nature of optical waveform change by group velocity dispersion.

    Science.gov (United States)

    Yamamoto, Takashi; Mori, Takayoshi; Sakamoto, Taiji; Kurokawa, Kenji; Tomita, Shigeru; Tsubokawa, Makoto

    2010-09-20

    We show that any optical pulse train recovers its original waveform after passing through a group velocity dispersion (GVD) device when the total GVD value of the device is equal to an integral multiple of 1/(2πf(rep)(2)), where f(rep) is the repetition rate of the optical pulse train. In addition, we detail our proposed GVD measurement method, or optical phase-modulation (PM) method, which utilizes a sinusoidally PM continuous wave (CW) light as a probe light. The total GVD B(2) of a device under test (DUT) is derived by using a very simple equation, |B(2)|=1/(2πf(null)(2)), where f(null) is the smallest modulation frequency at which the sinusoidally PM light becomes CW light again after passing through the DUT.

  2. Effects of resource availability and bacterivory on leucine incorporation in different groups of freshwater bacterioplankton, assessed using microautoradiography

    Czech Academy of Sciences Publication Activity Database

    Horňák, Karel; Jezbera, Jan; Nedoma, Jiří; Gasol, J.M.; Šimek, Karel

    2006-01-01

    Roč. 45, č. 3 (2006), s. 277-289 ISSN 0948-3055 R&D Projects: GA ČR GA206/05/0007 Grant - others:FRVŠ(CZ) 1062/2004 Institutional research plan: CEZ:AV0Z60170517 Keywords : leucin e incorporation * bacterial structure * bacterial function Subject RIV: EH - Ecology, Behaviour Impact factor: 2.209, year: 2006

  3. Performance and behaviour of rabbit does in a group-housing system with natural mating or artificial insemination

    NARCIS (Netherlands)

    Rommers, J.M.; Boiti, C.; Jong, de I.C.; Brecchia, G.

    2006-01-01

    This study compared reproductive performance and behaviour of does raised in a group-housing system and in a regular cage system. The group-housing pen was divided into different functional areas for suckling, resting, and eating and special hiding areas for kits when they had left the nest-boxes

  4. Molucular gene profiling of Clostridium botulinum group III and their detection in naturally contaminated samples originating from various European countries

    NARCIS (Netherlands)

    Woudstra, C.; LeMarechal, C.; Souillard, R.; Bäyon-Auboyer, M.H.; Anniballi, F.; Auricchio, B.; Medici, De D.; Bano, L.; Koene, M.G.J.; Sansonetti, M.H.; Hansbauer, E.M.; Desoutter, D.; Dorner, M.B.; Fach, P.; Dorner, B.G.

    2015-01-01

    We report the development of real-time PCR assays for genotyping Clostridium botulinum group III targeting the newly defined C. novyi sensu lato group; the nontoxic nonhemagglutinin (NTNH)-encoding gene ntnh; the botulinum neurotoxin (BoNT)-encoding genes bont/C, bont/C/D, bont/D, and bont/D/C; and

  5. Bacterioplankton from Two Hungarian Danube River Wetlands (Beda-Karapancsa, Danube-Drava National Park and its Relations to Environmental Variables

    Directory of Open Access Journals (Sweden)

    Kalcheva Hristina

    2016-04-01

    Full Text Available Seasonal and spatial distribution of bacterioplankton from two Hungarian oxbow lake type wetlands, Mocskos-Danube and Riha, was studied. They were both covered by macrophytes and they had different hydrological connectivity to the Danube. The six sampling campaigns from April to October 2014 included parallel samples from the Danube River at Mohács, Hungary. Bacterial abundance was the highest in spring and in Mocskos-Danube, followed by Mohács and Riha. Positive relationships existed between bacterioplankton and temperature on one hand and suspended solids, pH, PO4-P and chl-a on the other. Negative correlations were with DOC, dissolved oxygen and NH4-N.

  6. Post-mortem computed tomography coaxial cutting needle biopsy to facilitate the detection of bacterioplankton using PCR probes as a diagnostic indicator for drowning.

    Science.gov (United States)

    Rutty, Guy N; Johnson, Christopher; Amoroso, Jasmin; Robinson, Claire; Bradley, Carina J; Morgan, Bruno

    2017-01-01

    We report for the first time the use of coaxial cutting needle biopsy, guided by post-mortem computed tomography (PMCT), to sample internal body tissues for bacterioplankton PCR analysis to investigate drowning. This technical report describes the biopsy technique, the comparison of the needle biopsy and the invasive autopsy sampling results, as well as the PMCT and autopsy findings. By using this new biopsy sampling approach for bacterioplankton PCR, we have developed on previous papers describing the minimally invasive PMCT approach for the diagnosis of drowning. When such a system is used, the operator must take all precautions to avoid contamination of the core biopsy samples due to the sensitivity of PCR-based analytic systems.

  7. Parent and Child Perspectives on the Nature of Anxiety in Children and Young People with Autism Spectrum Disorders: A Focus Group Study

    Science.gov (United States)

    Ozsivadjian, Ann; Knott, Fiona; Magiati, Iliana

    2012-01-01

    Anxiety disorders are common among children and young people with autism spectrum disorders (ASD). Despite growing knowledge about the prevalence, phenomenology and treatment of anxiety disorders, relatively little is understood about the nature and impact of anxiety in this group and little is known about autism-specific factors that may have a…

  8. A tailored biocatalyst achieved by the rational anchoring of imidazole groups on a natural polymer: furnishing a potential artificial nuclease by sustainable materials engineering.

    Science.gov (United States)

    Ferreira, José G L; Grein-Iankovski, Aline; Oliveira, Marco A S; Simas-Tosin, Fernanda F; Riegel-Vidotti, Izabel C; Orth, Elisa S

    2015-04-11

    Foreseeing the development of artificial enzymes by sustainable materials engineering, we rationally anchored reactive imidazole groups on gum arabic, a natural biocompatible polymer. The tailored biocatalyst GAIMZ demonstrated catalytic activity (>10(5)-fold) in dephosphorylation reactions with recyclable features and was effective in cleaving plasmid DNA, comprising a potential artificial nuclease.

  9. Review of flavonoids: A diverse group of natural compounds with anti-Candida albicans activity in vitro.

    Science.gov (United States)

    Seleem, Dalia; Pardi, Vanessa; Murata, Ramiro Mendonça

    2017-04-01

    Flavonoids are a subdivision of polyphenols, a versatile class of natural compounds that represent secondary metabolites from higher plants and are abundant in human diet. Various protective effects of flavonoids have been reported, including antimicrobial and antifungal activities. Due to the nature of oral candidiasis and the increased use of antifungal agents, several drug-resistant strains have emerged making it impractical to rely on one standard therapeutic regime. The aim of this review is to summarize the antifungal activity of some examples of the major subclasses of flavonoids in pure extract forms against C. albicans in vitro, as reported in literature over the past 10 years (2004-2015). In addition, this review outlines the potential mechanism of actions of flavonoids studied in vitro, which may contribute to a better understanding of flavonoids as multi-targets agents in the treatment and/or prevention of oral candidiasis in clinical settings. Copyright © 2016. Published by Elsevier Ltd.

  10. Social Ecology and Group Cohesion in Pilot Whales and Their Responses to Playback of Anthropogenic and Natural Sounds

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Social ecology and group cohesion in pilot whales and their...N000141410410 LONG-TERM GOALS This project investigates the social ecology and cohesion of long-finned pilot whales as part of a broad multi...close associates within the same social group with sound and movement recording DTAGs (Johnson and Tyack, 2003). These tags sample a pair of

  11. Contrasting patterns of free-living bacterioplankton diversity in macrophyte-dominated versus phytoplankton blooming regimes in Dianchi Lake, a shallow lake in China

    Science.gov (United States)

    Wang, Yujing; Li, Huabing; Xing, Peng; Wu, Qinglong

    2017-03-01

    Freshwater shallow lakes typically exhibit two alternative stable states under certain nutrient loadings: macrophyte-dominated and phytoplankton-dominated water regimes. An ecosystem regime shift from macrophytes to phytoplankton blooming typically reduces the number of species of invertebrates and fishes and results in the homogenization of communities in freshwater lakes. We investigated how microbial biodiversity has responded to a shift of the ecosystem regime in Dianchi Lake, which was previously fully covered with submerged macrophytes but currently harbors both ecological states. We observed marked divergence in the diversity and community composition of bacterioplankton between the two regimes. Although species richness, estimated as the number of operational taxonomic units and phylogenetic diversity (PD), was higher in the phytoplankton dominated ecosystem after this shift, the dissimilarity of bacterioplankton community across space decreased. This decrease in beta diversity was accompanied by loss of planktonic bacteria unique to the macrophyte-dominated ecosystem. Mantel tests between bacterioplankton community distances and Euclidian distance of environmental parameters indicated that this reduced bacterial community differentiation primarily reflected the loss of environmental niches, particularly in the macrophyte regime. The loss of this small-scale heterogeneity in bacterial communities should be considered when assessing long-term biodiversity changes in response to ecosystem regime conversions in freshwater lakes.

  12. “It’ll Grow Organically and Naturally": The Reciprocal Relationship between Student Groups and Disability Studies on College Campuses

    Directory of Open Access Journals (Sweden)

    Allegra Stout

    2014-03-01

    Full Text Available Although few colleges and universities offer undergraduate disability studies curricula, our own experiences suggest that higher education settings provide opportunities for students to engage with and act upon disability studies theories and concepts. To learn more about the interactions between undergraduate student groups and disability studies, we interviewed students and faculty on three campuses. We found that students not only access disability studies theory through both formal and informal means, but that they also actively engage with it to develop their understandings of disability and interpret their experiences. Additionally, student groups educate their campus communities by advocating for the inclusion of disability studies in curricula, sharing their perspectives in the classroom, and hosting events related to disability studies. Through these activities, often in collaboration with faculty and staff, students forge reciprocal relationships between their activism and the field of disability studies. Keywords: Student groups, activism, advocacy, narrative, undergraduate education

  13. DiGIR1 and NaGIR1: naturally occurring group I-like ribozymes with unique core organization and evolved biological role

    DEFF Research Database (Denmark)

    Johansen, Steinar; Einvik, Christer; Nielsen, Henrik

    2002-01-01

    The group I-like ribozyme GIR1 is a unique example of a naturally occurring ribozyme with an evolved biological function. GIR1 generates the 5'-end of a nucleolar encoded messenger RNA involved in intron mobility. GIR1 is found as a cis-cleaving ribozyme within two very different rDNA group I...... introns (twin-ribozyme introns) in distantly related organisms. The Didymium GIR1 (DiGIR1) and Naegleria GIR1 (NaGIR1) share fundamental features in structural organization and reactivity, and display significant differences when compared to the related group I splicing ribozymes. GIR1 lacks...... the characteristic P1 segment present in all group I splicing ribozymes, it has a novel core organization, and it catalyses two site-specific hydrolytic cleavages rather than splicing. DiGIR1 and NaGIR1 appear to have originated from eubacterial group I introns in order to fulfil a common biological challenge...

  14. Report of study group 7.1: natural gas in competition with electric power in industrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Youssef, Ch.; Tatsuda, T.

    2000-07-01

    This report consists of three sections. The first section is a brief general overview of all the issues that impact the competition between natural gas and electricity in industrial applications. The second section of this report focus on the all the marketing issues and provides detail analysis of the status of these issues in Europe, Japan and United States. The third section of this report is a detail review of the current status of the competition between gas technologies and electro-technologies, it also make recommendation for developing new gas technologies. The fourth section is a contribution from M. Pettersson and S. Stenstroem, Sweden, on infrared dryers. (authors)

  15. Conformational control of cofactors in nature: The effect of methoxy group orientation on the electronic structure of ubisemiquinone

    Science.gov (United States)

    De Almeida, Wagner B.; O'Malley, Patrick J.

    2018-03-01

    Ubiquinone is the key electron and proton transfer agent in biology. Its mechanism involves the formation of its intermediate one-electron reduced form, the ubisemiquinone radical. This is formed in a protein-bound form which permits the semiquinone to vary its electronic and redox properties. This can be achieved by hydrogen bonding acceptance by one or both oxygen atoms or as we now propose by restricted orientations for the methoxy groups of the headgroup. We show how the orientation of the two methoxy groups of the quinone headgroup affects the electronic structure of the semiquinone form and demonstrate a large dependence of the ubisemiquinone spin density distribution on the orientation each methoxy group takes with respect to the headgroup ring plane. This is shown to significantly modify associated hyperfine couplings which in turn needs to be accounted for in interpreting experimental values in vivo. The study uncovers the key potential role the methoxy group orientation can play in controlling the electronic structure and spin density of ubisemiquinone and provides an electronic-level insight into the variation in electron affinity and redox potential of ubiquinone as a function of the methoxy orientation. Taken together with the already known influence of cofactor conformation on heme and chlorophyll electronic structure, it reveals a more widespread role for cofactor conformational control of electronic structure and associated electron transfer in biology.

  16. Molecular gene profiling of Clostridium botulinum group III and its detection in naturally contaminated samples originating from various European countries.

    Science.gov (United States)

    Woudstra, Cedric; Le Maréchal, Caroline; Souillard, Rozenn; Bayon-Auboyer, Marie-Hélène; Anniballi, Fabrizio; Auricchio, Bruna; De Medici, Dario; Bano, Luca; Koene, Miriam; Sansonetti, Marie-Hélène; Desoutter, Denise; Hansbauer, Eva-Maria; Dorner, Martin B; Dorner, Brigitte G; Fach, Patrick

    2015-04-01

    We report the development of real-time PCR assays for genotyping Clostridium botulinum group III targeting the newly defined C. novyi sensu lato group; the nontoxic nonhemagglutinin (NTNH)-encoding gene ntnh; the botulinum neurotoxin (BoNT)-encoding genes bont/C, bont/C/D, bont/D, and bont/D/C; and the flagellin (fliC) gene. The genetic diversity of fliC among C. botulinum group III strains resulted in the definition of five major subgroups named fliC-I to fliC-V. Investigation of fliC subtypes in 560 samples, with various European origins, showed that fliC-I was predominant and found exclusively in samples contaminated by C. botulinum type C/D, fliC-II was rarely detected, no sample was recorded as fliC-III or fliC-V, and only C. botulinum type D/C samples tested positive for fliC-IV. The lack of genetic diversity of the flagellin gene of C. botulinum type C/D would support a clonal spread of type C/D strains in different geographical areas. fliC-I to fliC-III are genetically related (87% to 92% sequence identity), whereas fliC-IV from C. botulinum type D/C is more genetically distant from the other fliC types (with only 50% sequence identity). These findings suggest fliC-I to fliC-III have evolved in a common environment and support a different genetic evolution for fliC-IV. A combination of the C. novyi sensu lato, ntnh, bont, and fliC PCR assays developed in this study allowed better characterization of C. botulinum group III and showed the group to be less genetically diverse than C. botulinum groups I and II, supporting a slow genetic evolution of the strains belonging to C. botulinum group III. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Taxonomy and natural history of the myrmecophilous genus Clinterocera Motschulsky, 1858 (Coleoptera: Scarabaeidae: Cetoniinae) from China and adjacent regions: definition of species group and revision of the C. discipennis species group.

    Science.gov (United States)

    Qiu, Jian-Yue; Xu, Hao

    2016-06-22

    The Asian genus Clinterocera Motschulsky, 1858 (Coleoptera: Scarabaeidae: Cetoniinae: Cremastocheilini) is redescribed and divided into four species groups based on adult external characters. The definition of species groups and an identification key to these species groups are provided. The C. discipennis species group is revised, and two species are recognized: C. discipennis Fairmaire, 1889 and C. trimaculata Ma, 1993. Callynomes rufiventris Fairmaire, 1904, Callynomes rufithorax Moser, 1901, Callynomes cruciatus Moser, 1901, Callynomes vitalisi (Bourgoin, 1924), and Clinterocera rubra Ma, 1992 are placed as junior synonyms of Clinterocera discipennis. The male of Clinterocera trimaculata is described for the first time and newly recorded from Vietnam. Diagnoses and illustrations of Clinterocera discipennis and Clinterocera trimaculata are provided, with comments on the intraspecific variations. New distribution records of the two species are presented on a map. Brief natural history notes and host ant Liometopum sinense Wheeler, 1921 (Hymenoptera: Formicidae) record of Clinterocera trimaculata are also given.

  18. Effect of the spacer group nature on the optical and electrical properties of confined poly( p-phenylene vinylene) derivatives

    Science.gov (United States)

    Benzarti-Ghédira, Maha; Zahou, Imen; Hrichi, Haikel; Jaballah, Nejmeddine; Ben Chaâbane, Rafik; Majdoub, Mustapha; Ben Ouada, Hafedh

    2015-09-01

    This study is an investigation about the effect of chemical modification on the morphological, optical and electrical properties of semiconducting organic thin films. Two confined poly( p-phenylene vinylene) (PPV)-type polymers containing different spacer groups were studied: P1 has an isopropylidene spacer group and P2 with hexafluoroisopropylidene spacer. The UV-Vis absorption and PL analysis showed a stronger π- π interaction in the P1 film; in P2, the π-stacking is limited by the introduction of a bulky trifluoromethyl (CF3) groups on the spacer units. The P2 exhibits a better film quality as illustrated by the atomic force microscopy. The HOMO and LUMO energy levels and electrochemical band gap of the polymers were determinate by the cyclic voltammetry. The electrical properties of ITO/PPV derivative/Al diodes were investigated by means of current-voltage and show a space-charge-limited current conduction mechanism with higher mobility in the P2 thin layer. The impedance spectra of the devices can be discussed in terms of an equivalent circuit model designed as a parallel resistance ( R p) and capacitance ( C p) network in series with a resistance.

  19. The nature of peptide interactions with acid end-group PLGAs and facile aqueous-based microencapsulation of therapeutic peptides

    OpenAIRE

    Sophocleous, Andreas M.; Desai, Kashappa-Goud H.; Mazzara, J. Maxwell; Tong, Ling; Cheng, Ji-Xin; Olsen, Karl F.; Schwendeman, Steven P.

    2013-01-01

    An important poorly understood phenomenon in controlled-release depots involves the strong interaction between common cationic peptides and low Mw free acid end-group poly(lactic-co-glycolic acids) (PLGAs) used to achieve continuous peptide release kinetics. The kinetics of peptide sorption to PLGA was examined by incubating peptide solutions of 0.2-4 mM octreotide or leuprolide acetate salts in 0.1 M HEPES buffer, pH 7.4, with polymer particles or films at 4-37 °C for 24 h. The extent of abs...

  20. The potential effect of age on the natural behavior of bladder cancer: Does urothelial cell carcinoma progress differently in various age groups?

    Science.gov (United States)

    Gunlusoy, Bulent; Ceylan, Yasin; Degirmenci, Tansu; Aydogdu, Ozgu; Bozkurt, Ibrahim Halil; Yonguc, Tarik; Sen, Volkan; Kozacioglu, Zafer

    2016-05-01

    We aimed to evaluate the potential effect of age on the natural behavior of bladder cancer and to compare these findings between different age groups. The clinical and pathologic data of 239 patients treated at our institution between 1994 and 2014 were analyzed. The patients were classified into three groups according to age: ≤ 40 years (Group 1), 41-59 years (Group 2), and ≥ 60 years (Group 3). The following data were collected: characteristics of the patients, initial pathological findings after transurethral resection, tumor stage and grade, tumor size and multiplicity, and disease recurrence and progression. The mean age of the patients at initial diagnosis was 34.2±5.5 years, 53±5.1 years, and 71.1±7 years in Groups 1, 2, and 3, respectively. There were 207 (86.6%) patients with nonmuscle-invasive urothelial bladder cancer and 32 (13.4%) patients with muscle-invasive disease. Tumor recurrence was significantly lower in Group 1 than in Group 2 (p=0.001) and Group 3 (p=0.001). Although the time to tumor recurrence was significantly different between the three groups (p=0.001), no significant difference was noted in the time to progression (p=0.349). Patients with urothelial cancer younger than 40 years tend to have single and small tumors. The tumor recurrence rate is lower in the younger age group, but tumor progression is similar in older and younger patients. Therefore, the findings indicate that clinicians should be careful when assessing the invasiveness of urothelial tumors in younger patients and start treatment as soon as possible. Copyright © 2016. Published by Elsevier Taiwan.

  1. Reaction of oxygen with γ, δ-ethylenic phenylhydrazones. Model reaction of end-group behavior in phenylhydrazine-accelerated oxidation of natural rubber

    International Nuclear Information System (INIS)

    El Hamdaoui, A.; Reyx, D.; Campistron, I.

    1995-01-01

    An accurate definition of terminal groups of chains in the liquid polymers obtained by the phenylhydrazine-accelerated oxidation of natural rubber is needed. The object of the work was to use model molecules to explore the behavior of γ,δ-ethylenic methylketone phenylhydrazone end-groups in oxidation conditions. We have investigated the synthesis and characterization of models of these hypothetical end-groups, methylketones and phenones 1, their phenylhydrazones 2, the α-(phenyldiazenyl)hydroperoxides 3 resulting from reaction of 2 with oxygen, and the α-(phenyldiazenyl)alcohols 4 as characteristic derivatives of 3 or as models of possible reduced structures in oxidized liquid natural rubber. Three original syntheses of γ,δ-ethylenic ketones were carried out. In the case of γ,δ-ethylenic phenylhydrazones, the oxidation led to the expected α-(phenyldiazenyl)hydroperoxides and to epoxide derivatives of α-(phenyldiazenyl)alcohols 5 and ketones 6. An intramolecular mechanism is proposed. The results are used to predict the possibilities of identification of the corresponding end-groups in liquid rubbers produced in this way. (authors). 16 refs., 12 figs., 3 tabs

  2. Feeling like a group after a natural disaster: Common ingroup identity and relations with outgroup victims among majority and minority young children.

    Science.gov (United States)

    Vezzali, Loris; Cadamuro, Alessia; Versari, Annalisa; Giovannini, Dino; Trifiletti, Elena

    2015-09-01

    We conducted a field study to test whether the common ingroup identity model (Gaertner & Dovidio, 2000, reducing intergroup bias: The common ingroup identity model. Philadelphia, PA: Psychology Press) could be a useful tool to improve intergroup relations in the aftermath of a natural disaster. Participants were majority (Italian) and minority (immigrant) elementary school children (N = 517) living in the area struck by powerful earthquakes in May 2012. Results revealed that, among majority children, the perceived external threat represented by the earthquake was associated with greater perceptions of belonging to a common ingroup including both ingroup and outgroup. In turn, heightened one-group perceptions were associated with greater willingness to meet and help outgroup victims, both directly and indirectly via more positive outgroup attitudes. Among immigrant children, perceived disaster threat was not associated with any of the dependent variables; one-group perceptions were positively associated with outgroup attitudes, helping and contact intentions towards outgroup victims. Thus, one-group perceptions after a natural disaster may promote more positive and supporting relations between the majority and the minority group. We discuss the theoretical and practical implications of the findings. © 2014 The British Psychological Society.

  3. Induction of Broadly Cross-Reactive Stalk-Specific Antibody Responses to Influenza Group 1 and Group 2 Hemagglutinins by Natural H7N9 Virus Infection in Humans.

    Science.gov (United States)

    Liu, Lu; Nachbagauer, Raffael; Zhu, Lingyan; Huang, Yang; Xie, Xinci; Jin, Shan; Zhang, Anli; Wan, Yanmin; Hirsh, Ariana; Tian, Di; Shi, Xiaolin; Dong, Zhaoguang; Yuan, Songhua; Hu, Yunwen; Krammer, Florian; Zhang, Xiaoyan; Xu, Jianqing

    2017-02-15

    The outbreak of novel avian H7N9 influenza virus infections in China in 2013 has demonstrated the continuing threat posed by zoonotic pathogens. Deciphering the immune response during natural infection will guide future vaccine development. We assessed the induction of heterosubtypic cross-reactive antibodies induced by H7N9 infection against a large panel of recombinant hemagglutinins and neuraminidases by quantitative enzyme-linked immunosorbent assay, and novel chimeric hemagglutinin constructs were used to dissect the anti-stalk or -head humoral immune response. H7N9 infection induced strong antibody responses against divergent H7 hemagglutinins. Interestingly, we also found induction of antibodies against heterosubtypic hemagglutinins from both group 1 and group 2 and a boost in heterosubtypic neutralizing activity in the absence of hemagglutination inhibitory activity. Kinetic monitoring revealed that heterosubtypic binding/neutralizing antibody responses typically appeared and peaked earlier than intrasubtypic responses, likely mediated by memory recall responses. Our results indicate that cross-group binding and neutralizing antibody responses primarily targeting the stalk region can be elicited after natural influenza virus infection. These data support our understanding of the breadth of the postinfection immune response that could inform the design of future, broadly protective influenza virus vaccines.

  4. Constraining the Nature of Dark Matter with the Star-formation History of the Faintest Local Group Dwarf Galaxy Satellites

    Energy Technology Data Exchange (ETDEWEB)

    Chau, Alice; Mayer, Lucio [Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); Governato, Fabio [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States)

    2017-08-10

    Λ warm dark matter (ΛWDM), realized by collisionless particles of 1–3 keV, has been proposed as an alternative scenario to Λ-Cold-Dark Matter (ΛCDM) for the dwarf galaxy scale discrepancies. We present an approach to test the viability of such WDM models using star-formation histories (SFHs) of the dwarf spheroidal galaxies (dSphs) in the Local Group. We compare their high-time-resolution SFHs with the collapse redshift of their dark halos in CDM and WDM. Collapse redshift is inferred after determining the subhalo infall mass. This is based on the dwarf current mass inferred from stellar kinematics, combined with cosmological simulation results on subhalo evolution. WDM subhalos close to the filtering mass scale, forming significantly later than CDM, are the most difficult to reconcile with early truncation of star formation ( z ≥ 3). The ultra-faint dwarfs (UFDs) provide the most stringent constraints. Using six UFDs and eight classical dSphs, we show that a 1 keV particle is strongly disfavored, consistently with other reported methods. Excluding other models is only hinted for a few UFDs. Other UFDs for which the lack of robust constraints on halo mass prevents us from carrying out our analysis rigorously, show a very early onset of star formation that will strengthen the constraints delivered by our method in the future. We discuss the various caveats, notably the low number of dwarfs with accurately determined SFHs and the uncertainties when determining the subhalo infall mass, most notably the baryonic physics. Our preliminary analysis may serve as a pathfinder for future investigations that will combine accurate SFHs for local dwarfs with direct analysis of WDM simulations with baryons.

  5. The nature of peptide interactions with acid end-group PLGAs and facile aqueous-based microencapsulation of therapeutic peptides.

    Science.gov (United States)

    Sophocleous, Andreas M; Desai, Kashappa-Goud H; Mazzara, J Maxwell; Tong, Ling; Cheng, Ji-Xin; Olsen, Karl F; Schwendeman, Steven P

    2013-12-28

    An important poorly understood phenomenon in controlled-release depots involves the strong interaction between common cationic peptides and low Mw free acid end-group poly(lactic-co-glycolic acids) (PLGAs) used to achieve continuous peptide release kinetics. The kinetics of peptide sorption to PLGA was examined by incubating peptide solutions of 0.2-4mM octreotide or leuprolide acetate salts in a 0.1M HEPES buffer, pH7.4, with polymer particles or films at 4-37°C for 24h. The extent of absorption/loading of peptides in PLGA particles/films was assayed by two-phase extraction and amino acid analysis. Confocal Raman microspectroscopy, stimulated Raman scattering (SRS) and laser scanning confocal imaging, and microtome sectioning techniques were used to examine peptide penetration into the polymer phase. The release of sorbed peptide from leuprolide-PLGA particles was evaluated both in vitro (PBST+0.02% sodium azide, 37°C) and in vivo (male Sprague-Dawley rats). We found that when the PLGA-COOH chains are sufficiently mobilized, therapeutic peptides not only bind at the surface, a common belief to date, but also can be internalized and distributed throughout the polymer phase at physiological temperature forming a salt with low-molecular weight PLGA-COOH. Importantly, absorption of leuprolide into low MW PLGA-COOH particles yielded ~17 wt.% leuprolide loading in the polymer (i.e., ~70% of PLGA-COOH acids occupied), and the absorbed peptide was released from the polymer for >2 weeks in a controlled fashion in vitro and as indicated by sustained testosterone suppression in male Sprague-Dawley rats. This new approach, which bypasses the traditional encapsulation method and associated production cost, opens up the potential for facile production of low-cost controlled-release injectable depots for leuprolide and related peptides. © 2013.

  6. Influence of humic acids on the migration behavior of radioactive and non-radioactive substances under conditions close to nature. Synthesis, radiometric determination of functional groups, complexation

    International Nuclear Information System (INIS)

    Pompe, S.; Bubner, M.; Schmeide, K.; Heise, K.H.; Bernhard, G.; Nitsche, H.

    2000-04-01

    The interaction behavior of humic acids with uranium(VI) and the influence of humic substances on the migration behavior of uranium was investigated. A main focus of this work was the synthesis of four different humic acid model substances and their characterization and comparison to the natural humic acid from Aldrich. A radiometric method for the determination of humic acid functional groups was applied in addition to conventional methods for the determination of the functionality of humic acids. The humic acid model substances show functional and structural properties comparable to natural humic acids. Modified humic acids with blocked phenolic OH were synthesized to determine the influence of phenolic OH groups on the complexation behavior of humic acids. A synthesis method for 14 C-labeled humic acids with high specific activity was developed. The complexation behavior of synthetic and natural humic acids with uranium(VI) was investigated by X-ray absorption spectroscopy, laser-induced fluorescence spectroscopy and FTIR spectroscopy. The synthetic model substances show an interaction behavior with uranium(VI) that is comparable to natural humic acids. This points to the fact that the synthetic humic acids simulate the functionality of their natural analogues very well. For the first time the influence of phenolic OH groups on the complexation behavior of humic acids was investigated by applying a modified humic acid with blocked phenolic OH groups. The formation of a uranyl hydroxy humate complex was identified by laserspectroscopic investigations of the complexation of Aldrich humic acid with uranium(VI) at pH7. The migration behavior of uranium in a sandy aquifer system rich in humic substances was investigated in column experiments. A part of uranium migrates non-retarded through the sediment, bound to humic colloids. The uranium migration behavior is strongly influenced by the kinetically controlled interaction processes of uranium with the humic colloids

  7. Composition influences the pathway but not the outcome of the metabolic response of bacterioplankton to resource shifts.

    Directory of Open Access Journals (Sweden)

    Jérôme Comte

    Full Text Available Bacterioplankton community metabolism is central to the functioning of aquatic ecosystems, and strongly reactive to changes in the environment, yet the processes underlying this response remain unclear. Here we explore the role that community composition plays in shaping the bacterial metabolic response to resource gradients that occur along aquatic ecotones in a complex watershed in Québec. Our results show that the response is mediated by complex shifts in community structure, and structural equation analysis confirmed two main pathways, one involving adjustments in the level of activity of existing phylotypes, and the other the replacement of the dominant phylotypes. These contrasting response pathways were not determined by the type or the intensity of the gradients involved, as we had hypothesized, but rather it would appear that some compositional configurations may be intrinsically more plastic than others. Our results suggest that community composition determines this overall level of community plasticity, but that composition itself may be driven by factors independent of the environmental gradients themselves, such that the response of bacterial communities to a given type of gradient may alternate between the adjustment and replacement pathways. We conclude that community composition influences the pathways of response in these bacterial communities, but not the metabolic outcome itself, which is driven by the environment, and which can be attained through multiple alternative configurations.

  8. Response of marine bacterioplankton to a massive under-ice phytoplankton bloom in the Chukchi Sea (Western Arctic Ocean)

    Science.gov (United States)

    Ortega-Retuerta, E.; Fichot, C. G.; Arrigo, K. R.; Van Dijken, G. L.; Joux, F.

    2014-07-01

    The activity of heterotrophic bacterioplankton and their response to changes in primary production in the Arctic Ocean is essential to understand biogenic carbon flows in the area. In this study, we explored the patterns of bacterial abundance (BA) and bacterial production (BP) in waters coinciding with a massive under-ice phytoplankton bloom in the Chukchi Sea in summer 2011, where chlorophyll a (chl a) concentrations were up to 38.9 mg m-3. Contrary to our expectations, BA and BP did not show their highest values coinciding with the bloom. In fact, bacterial biomass was only 3.5% of phytoplankton biomass. Similarly, average DOC values were similar inside (average 57.2±3.1 μM) and outside (average 64.3±4.8 μM) the bloom patch. Regression analyses showed relatively weak couplings, in terms of slope values, between chl a or primary production and BA or BP. Multiple regression analyses indicated that both temperature and chl a explained BA and BP variability in the Chukchi Sea. This temperature dependence was confirmed experimentally, as higher incubation temperatures (6.6 °C vs. 2.2 °C) enhanced BA and BP, with Q10 values of BP up to 20.0. Together, these results indicate that low temperatures in conjunction with low dissolved organic matter release can preclude bacteria to efficiently process a higher proportion of carbon fixed by phytoplankton, with further consequences on the carbon cycling in the area.

  9. Simultaneous natural speech and AAC interventions for children with childhood apraxia of speech: lessons from a speech-language pathologist focus group.

    Science.gov (United States)

    Oommen, Elizabeth R; McCarthy, John W

    2015-03-01

    In childhood apraxia of speech (CAS), children exhibit varying levels of speech intelligibility depending on the nature of errors in articulation and prosody. Augmentative and alternative communication (AAC) strategies are beneficial, and commonly adopted with children with CAS. This study focused on the decision-making process and strategies adopted by speech-language pathologists (SLPs) when simultaneously implementing interventions that focused on natural speech and AAC. Eight SLPs, with significant clinical experience in CAS and AAC interventions, participated in an online focus group. Thematic analysis revealed eight themes: key decision-making factors; treatment history and rationale; benefits; challenges; therapy strategies and activities; collaboration with team members; recommendations; and other comments. Results are discussed along with clinical implications and directions for future research.

  10. Impacts of combined overfishing and oil spills on the plankton trophodynamics of the West Florida shelf over the last half century of 1965-2011: A two-dimensional simulation analysis of biotic state transitions, from a zooplankton- to a bacterioplankton-modulated ecosystem.

    Science.gov (United States)

    Walsh, J. J.; Lenes, J. M.; Darrow, B.; Parks, A.; Weisberg, R. H.

    2016-03-01

    Over 50 years of multiple anthropogenic perturbations, Florida zooplankton stocks of the northeastern Gulf of Mexico declined ten-fold, with increments of mainly dominant toxic dinoflagellate harmful algal blooms (HABs), rather than diatoms, and a shift in loci of nutrient remineralization and oxygen depletion by bacterioplankton, from the sea floor to near surface waters. Yet, lytic bacterial biomass and associated ammonification only increased at most five-fold over the same time period, with consequently little indication of new, expanded "dead zones" of diatom-induced hypoxia. After bacterial lysis of intact cells of these increased HABs, the remaining residues of zooplankton biomass decrements evidently instead exited the water column as malign aerosolized HAB asthma triggers, correlated by co-traveling mercury aerosols, within wind-borne sea sprays. To unravel the causal mechanisms of these inferred decadal food web transitions, a 36-state variable plankton model of algal, bacterial, protozoan, and copepod component communities replicated daily time series of each plankton group's representatives on the West Florida shelf (WFS) during 1965-2011. At the lower phytoplankton trophic levels, 52% of the ungrazed HAB increments, between 1965-1967 and 2001-2002 before recent oil spills, remained in the water column to kill fishes and fuel bacterioplankton. But, another 48% of the WFS primary production then left the ocean's surface as a harbinger of increased public health hazards during continuing sea spray exports of salts, HAB toxins, and Hg poisons. Following the Deepwater Horizon petroleum releases in 2010, little additional change of element partition among the altered importance of WFS food web components of the trophic pyramid then pertained between 2001-2002 and 2010-2011, despite when anomalous upwelled nutrient supplies instead favored retrograde benign, oil-tolerant diatoms over the HABs during 2010. Indeed, by 2011 HABs were back, with biomass

  11. Importance of Antibodies to Lipopolysaccharide in Natural and Vaccine-Induced Serum Bactericidal Activity against Neisseria meningitidis Group B▿†

    Science.gov (United States)

    Schmiel, Deborah H.; Moran, Elizabeth E.; Keiser, Paul B.; Brandt, Brenda L.; Zollinger, Wendell D.

    2011-01-01

    Analysis of the specificity of bactericidal antibodies in normal, convalescent, and postvaccination human sera is important in understanding human immunity to meningococcal infections and can aid in the design of an effective group B vaccine. A collection of human sera, including group C and group B convalescent-phase sera, normal sera with naturally occurring cross-reactive bactericidal activity, and some postvaccination sera, was analyzed to determine the specificity of cross-reactive bactericidal antibodies. Analysis of human sera using a bactericidal antibody depletion assay demonstrated that a significant portion of the bactericidal activity could be removed by purified lipopolysaccharide (LPS). LPS homologous to that expressed on the bactericidal test strain was most effective, but partial depletion by heterologous LPS suggested the presence of antibodies with various degrees of cross-reactivity. Binding of anti-L3,7 LPS bactericidal antibodies was affected by modification of the core structure, suggesting that these functional antibodies recognized epitopes consisting of both core structures and lacto-N-neotetraose (LNnT). When the target strain was grown with 5′-cytidinemonophospho-N-acetylneuraminic acid (CMP-NANA) to increase LPS sialylation, convalescent-phase serum bactericidal titers were decreased by only 2- to 4-fold, and most remaining bactericidal activity was still depleted by LPS. Highly sialylated LPS was ineffective in depleting bactericidal antibodies. We conclude that natural infections caused by strains expressing L3,7 LPS induce persistent, protective bactericidal antibodies and appear to be directed against nonsialylated bacterial epitopes. Additionally, subsets of these bactericidal antibodies are cross-reactive, binding to several different LPS immunotypes, which is a useful characteristic for an effective group B meningococcal vaccine antigen. PMID:21768280

  12. THE COOPERATIVE INTERNATIONAL NEUROMUSCULAR RESEARCH GROUP DUCHENNE NATURAL HISTORY STUDY—A LONGITUDINAL INVESTIGATION IN THE ERA OF GLUCOCORTICOID THERAPY: DESIGN OF PROTOCOL AND THE METHODS USED

    Science.gov (United States)

    McDonald, Craig M.; Henricson, Erik K.; Abresch, R. Ted; Han, Jay J.; Escolar, Diana M.; Florence, Julaine M.; Duong, Tina; Arrieta, Adrienne; Clemens, Paula R.; Hoffman, Eric P.; Cnaan, Avital

    2014-01-01

    Contemporary natural history data in Duchenne muscular dystrophy (DMD) is needed to assess care recommendations and aid in planning future trials. Methods The Cooperative International Neuromuscular Research Group (CINRG) DMD Natural History Study (DMD-NHS) enrolled 340 individuals, aged 2–28 years, with DMD in a longitudinal, observational study at 20 centers. Assessments obtained every 3 months for 1 year, at 18 months, and annually thereafter included: clinical history; anthropometrics; goniometry; manual muscle testing; quantitative muscle strength; timed function tests; pulmonary function; and patient-reported outcomes/ health-related quality-of-life instruments. Results Glucocorticoid (GC) use at baseline was 62% present, 14% past, and 24% GC-naive. In those ≥6 years of age, 16% lost ambulation over the first 12 months (mean age 10.8 years). Conclusions Detailed information on the study methodology of the CINRG DMD-NHS lays the groundwork for future analyses of prospective longitudinal natural history data. These data will assist investigators in designing clinical trials of novel therapeutics. PMID:23677550

  13. Evolution of Chemical Diversity in a Group of Non-Reduced Polyketide Gene Clusters: Using Phylogenetics to Inform the Search for Novel Fungal Natural Products

    Directory of Open Access Journals (Sweden)

    Kurt Throckmorton

    2015-09-01

    Full Text Available Fungal polyketides are a diverse class of natural products, or secondary metabolites (SMs, with a wide range of bioactivities often associated with toxicity. Here, we focus on a group of non-reducing polyketide synthases (NR-PKSs in the fungal phylum Ascomycota that lack a thioesterase domain for product release, group V. Although widespread in ascomycete taxa, this group of NR-PKSs is notably absent in the mycotoxigenic genus Fusarium and, surprisingly, found in genera not known for their secondary metabolite production (e.g., the mycorrhizal genus Oidiodendron, the powdery mildew genus Blumeria, and the causative agent of white-nose syndrome in bats, Pseudogymnoascus destructans. This group of NR-PKSs, in association with the other enzymes encoded by their gene clusters, produces a variety of different chemical classes including naphthacenediones, anthraquinones, benzophenones, grisandienes, and diphenyl ethers. We discuss the modification of and transitions between these chemical classes, the requisite enzymes, and the evolution of the SM gene clusters that encode them. Integrating this information, we predict the likely products of related but uncharacterized SM clusters, and we speculate upon the utility of these classes of SMs as virulence factors or chemical defenses to various plant, animal, and insect pathogens, as well as mutualistic fungi.

  14. Environmental health research recommendations from the Inter-Environmental Health Sciences Core Center Working Group on unconventional natural gas drilling operations.

    Science.gov (United States)

    Penning, Trevor M; Breysse, Patrick N; Gray, Kathleen; Howarth, Marilyn; Yan, Beizhan

    2014-11-01

    Unconventional natural gas drilling operations (UNGDO) (which include hydraulic fracturing and horizontal drilling) supply an energy source that is potentially cleaner than liquid or solid fossil fuels and may provide a route to energy independence. However, significant concerns have arisen due to the lack of research on the public health impact of UNGDO. Environmental Health Sciences Core Centers (EHSCCs), funded by the National Institute of Environmental Health Sciences (NIEHS), formed a working group to review the literature on the potential public health impact of UNGDO and to make recommendations for needed research. The Inter-EHSCC Working Group concluded that a potential for water and air pollution exists that might endanger public health, and that the social fabric of communities could be impacted by the rapid emergence of drilling operations. The working group recommends research to inform how potential risks could be mitigated. Research on exposure and health outcomes related to UNGDO is urgently needed, and community engagement is essential in the design of such studies.

  15. Host Factors Influencing the Retrohoming Pathway of Group II Intron RmInt1, Which Has an Intron-Encoded Protein Naturally Devoid of Endonuclease Activity.

    Directory of Open Access Journals (Sweden)

    Rafael Nisa-Martínez

    Full Text Available Bacterial group II introns are self-splicing catalytic RNAs and mobile retroelements that have an open reading frame encoding an intron-encoded protein (IEP with reverse transcriptase (RT and RNA splicing or maturase activity. Some IEPs carry a DNA endonuclease (En domain, which is required to cleave the bottom strand downstream from the intron-insertion site for target DNA-primed reverse transcription (TPRT of the inserted intron RNA. Host factors complete the insertion of the intron. By contrast, the major retrohoming pathway of introns with IEPs naturally lacking endonuclease activity, like the Sinorhizobium meliloti intron RmInt1, is thought to involve insertion of the intron RNA into the template for lagging strand DNA synthesis ahead of the replication fork, with possible use of the nascent strand to prime reverse transcription of the intron RNA. The host factors influencing the retrohoming pathway of such introns have not yet been described. Here, we identify key candidates likely to be involved in early and late steps of RmInt1 retrohoming. Some of these host factors are common to En+ group II intron retrohoming, but some have different functions. Our results also suggest that the retrohoming process of RmInt1 may be less dependent on the intracellular free Mg2+ concentration than those of other group II introns.

  16. Co-occurrence Analysis of Microbial Taxa in the Atlantic Ocean Reveals High Connectivity in the Free-Living Bacterioplankton

    Science.gov (United States)

    Milici, Mathias; Deng, Zhi-Luo; Tomasch, Jürgen; Decelle, Johan; Wos-Oxley, Melissa L.; Wang, Hui; Jáuregui, Ruy; Plumeier, Iris; Giebel, Helge-Ansgar; Badewien, Thomas H.; Wurst, Mascha; Pieper, Dietmar H.; Simon, Meinhard; Wagner-Döbler, Irene

    2016-01-01

    We determined the taxonomic composition of the bacterioplankton of the epipelagic zone of the Atlantic Ocean along a latitudinal transect (51°S–47°N) using Illumina sequencing of the V5-V6 region of the 16S rRNA gene and inferred co-occurrence networks. Bacterioplankon community composition was distinct for Longhurstian provinces and water depth. Free-living microbial communities (between 0.22 and 3 μm) were dominated by highly abundant and ubiquitous taxa with streamlined genomes (e.g., SAR11, SAR86, OM1, Prochlorococcus) and could clearly be separated from particle-associated communities which were dominated by Bacteroidetes, Planktomycetes, Verrucomicrobia, and Roseobacters. From a total of 369 different communities we then inferred co-occurrence networks for each size fraction and depth layer of the plankton between bacteria and between bacteria and phototrophic micro-eukaryotes. The inferred networks showed a reduction of edges in the deepest layer of the photic zone. Networks comprised of free-living bacteria had a larger amount of connections per OTU when compared to the particle associated communities throughout the water column. Negative correlations accounted for roughly one third of the total edges in the free-living communities at all depths, while they decreased with depth in the particle associated communities where they amounted for roughly 10% of the total in the last part of the epipelagic zone. Co-occurrence networks of bacteria with phototrophic micro-eukaryotes were not taxon-specific, and dominated by mutual exclusion (~60%). The data show a high degree of specialization to micro-environments in the water column and highlight the importance of interdependencies particularly between free-living bacteria in the upper layers of the epipelagic zone. PMID:27199970

  17. Co-occurrence Analysis of Microbial Taxa in the Atlantic Ocean Reveals High Connectivity in the Free-Living Bacterioplankton.

    Science.gov (United States)

    Milici, Mathias; Deng, Zhi-Luo; Tomasch, Jürgen; Decelle, Johan; Wos-Oxley, Melissa L; Wang, Hui; Jáuregui, Ruy; Plumeier, Iris; Giebel, Helge-Ansgar; Badewien, Thomas H; Wurst, Mascha; Pieper, Dietmar H; Simon, Meinhard; Wagner-Döbler, Irene

    2016-01-01

    We determined the taxonomic composition of the bacterioplankton of the epipelagic zone of the Atlantic Ocean along a latitudinal transect (51°S-47°N) using Illumina sequencing of the V5-V6 region of the 16S rRNA gene and inferred co-occurrence networks. Bacterioplankon community composition was distinct for Longhurstian provinces and water depth. Free-living microbial communities (between 0.22 and 3 μm) were dominated by highly abundant and ubiquitous taxa with streamlined genomes (e.g., SAR11, SAR86, OM1, Prochlorococcus) and could clearly be separated from particle-associated communities which were dominated by Bacteroidetes, Planktomycetes, Verrucomicrobia, and Roseobacters. From a total of 369 different communities we then inferred co-occurrence networks for each size fraction and depth layer of the plankton between bacteria and between bacteria and phototrophic micro-eukaryotes. The inferred networks showed a reduction of edges in the deepest layer of the photic zone. Networks comprised of free-living bacteria had a larger amount of connections per OTU when compared to the particle associated communities throughout the water column. Negative correlations accounted for roughly one third of the total edges in the free-living communities at all depths, while they decreased with depth in the particle associated communities where they amounted for roughly 10% of the total in the last part of the epipelagic zone. Co-occurrence networks of bacteria with phototrophic micro-eukaryotes were not taxon-specific, and dominated by mutual exclusion (~60%). The data show a high degree of specialization to micro-environments in the water column and highlight the importance of interdependencies particularly between free-living bacteria in the upper layers of the epipelagic zone.

  18. Co-occurrence analysis of microbial taxa in the Atlantic Ocean reveals high connectivity in the free-living bacterioplankton

    Directory of Open Access Journals (Sweden)

    Mathias eMilici

    2016-05-01

    Full Text Available We determined the taxonomic composition of the bacterioplankton of the epipelagic zone of the Atlantic Ocean along a latitudinal transect (51°S – 47°N using Illumina sequencing of the V5-V6 region of the 16S rRNA gene and inferred co-occurrence networks. Bacterioplankon community composition was distinct for Longhurstian provinces and water depth. Free-living microbial communities (between 0.22-3 µm were dominated by highly abundant and ubiquitous taxa with streamlined genomes (e.g. SAR11, SAR86, OM1, Prochlorococcus and could clearly be separated from particle-associated communities which were dominated by Bacteroidetes, Planktomycetes, Verrucomicrobia and Roseobacters. From a total of 369 different communities we then inferred co-occurrence networks for each size fraction and depth layer of the plankton between bacteria and between bacteria and phototrophic micro-eukaryotes. The inferred networks showed a reduction of edges in the deepest layer of the photic zone. Networks comprised of free-living bacteria had a larger amount of connections per OTU when compared to the particle associated communities throughout the water column. Negative correlations accounted for roughly one third of the total edges in the free-living communities at all depths, while they decreased with depth in the particle associated communities where they amounted for roughly 10% of the total in the last part of the epipelagic zone. Co-occurrence networks of bacteria with phototrophic micro-eukaryotes were not taxon-specific, and dominated by mutual exclusion (~60%. The data show a high degree of specialization to micro-environments in the water column and highlight the importance of interdependencies particularly between free-living bacteria in the upper layers of the epipelagic zone.

  19. A Mixed-Methods Trial of Broad Band Noise and Nature Sounds for Tinnitus Therapy: Group and Individual Responses Modeled under the Adaptation Level Theory of Tinnitus

    Science.gov (United States)

    Durai, Mithila; Searchfield, Grant D.

    2017-01-01

    for sound effectiveness. The different rates of adaptation to broadband noise and nature sound by the auditory system may explain the different tinnitus loudness level matches. In addition to group effects there also appears to be a great deal of individual variation. A sound therapy framework based on adaptation level theory is proposed that accounts for individual variation in preference and response to sound. Clinical Trial Registration: www.anzctr.org.au, identifier #12616000742471. PMID:28337139

  20. Effects of hexavalent chromium on phytoplankton and bacterioplankton of the Río de la Plata estuary: an ex-situ assay.

    Science.gov (United States)

    Sathicq, María Belén; Gómez, Nora

    2018-03-17

    We examined the responses of the phytoplankton and the bacterioplankton of the freshwater zone of the Río de la Plata estuary when exposed to an addition of hexavalent chromium (Cr +6 ). The planktonic community from a coastal site was exposed to a chromium increase of 80 μg L -1 for 72 h in laboratory conditions. The results showed a decrease in the concentration of Cr +6 by 33% in the treatments, along with significant decreases in chlorophyll-a (63%), the chlorophyll-a:pheophytin-a ratio (33%), oxygen production (37%), and in the total density of the phytoplankton (15%). The relative abundance of chlorophytes and diatoms decreased, while the cyanobacteria thrived. Finally, the total bacterial density and the density of viable bacteria decreased. These results show that even small increments in Cr +6 can cause significant effects on the phytoplankton and bacterioplankton, which could potentially affect other trophic levels of the community, risking alterations of the entire ecosystem.

  1. Successional trajectories of bacterioplankton community over the complete cycle of a sudden phytoplankton bloom in the Xiangshan Bay, East China Sea.

    Science.gov (United States)

    Chen, Heping; Zhang, Huajun; Xiong, Jinbo; Wang, Kai; Zhu, Jianlin; Zhu, Xiangyu; Zhou, Xiaoyan; Zhang, Demin

    2016-12-01

    Phytoplankton bloom has imposed ecological concerns worldwide; however, few studies have been focused on the successional trajectories of bacterioplankton community over a complete phytoplankton bloom cycle. Using 16S pyrosequencing, we investigated how the coastal bacterioplankton community compositions (BCCs) respond to a phytoplankton bloom in the Xiangshan Bay, East China Sea. The results showed that BCCs were significantly different among the pre-bloom, bloom, and after-bloom stages, with the lowest bacterial diversity at the bloom phase. The BCCs at the short-term after-bloom phase showed a rapid but incomplete recovery to the pre-bloom phase, evidenced by 69.8% similarity between pre-bloom and after-bloom communities. This recovery was parallel with the dynamics of the operational taxonomic units (OTUs) affiliated with Actinobacteria, Bacteroidetes, Cyanobacteria, Alphaproteobacteria and Gammaproteobacteria, whose abundance enriched when bloom occur, and decreased after-bloom, and vice versa. Collectively, the results showed that the BCCs were sensitive to algal-induced disturbances, but could recover to a certain extent after bloom. In addition, OTUs which enriched or decreased during this process are closely associated with this temporal pattern, thus holding the potential to evaluate and indicate the succession stage of phytoplankton bloom. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Summary of Recommendations of the GBIF Task Group on the Global Strategy and Action Plan for the Digitisation of Natural History Collections

    Directory of Open Access Journals (Sweden)

    Walter G. Berendsohn

    2010-10-01

    Full Text Available The Global Biodiversity Information Facility’s Task Group has formulated three basic recommendations to the GBIF Governing Board in order to increase the rate of the digitization of natural history collections and improve the usage of this information resource: (i GBIF must facilitate access to information about non-digitized collection resources by publicizing the research potential of collections through metadata and assessing the number of non-digitized specimens; (ii GBIF must work with collections to continue to increase the efficiency of specimen data capture and to enhance data quality by means of technical measures, by means of ensuring attribution and professional credit and influencing institutional priorities, and by engaging with funding agencies; (iii GBIF must continue to improve and promote the global infrastructure used to mobilize digitized collection data through technical measures, outreach activities and political measures.

  3. Lie Group Analysis of Natural Convective Flow from a Convectively Heated Upward Facing Radiating Permeable Horizontal Plate in Porous Media Filled with Nanofluid

    Directory of Open Access Journals (Sweden)

    Md. Jashim Uddin

    2012-01-01

    Full Text Available Two-dimensional, steady, laminar and incompressible natural convective flow of a nanofluid over a connectively heated permeable upward facing radiating horizontal plate in porous medium is studied numerically. The present model incorporates Brownian motion and thermophoresis effects. The similarity transformations for the governing equations are developed by Lie group analysis. The transformed equations are solved numerically by Runge-Kutta-Fehlberg fourth-fifth order method with shooting technique. Effects of the governing parameters on the dimensionless velocity, temperature and nanoparticle volume fraction as well as on the dimensionless rate of heat and mass transfer are presented graphically and the results are compared with the published data for special cases. Good agreement is found between numerical results of the present paper and published results. It is found that Lewis number, Brownian motion and convective heat transfer parameters increase the heat and mass transfer rates whilst thermophoresis decreases both heat and mass transfer rates.

  4. Group Grammar

    Science.gov (United States)

    Adams, Karen

    2015-01-01

    In this article Karen Adams demonstrates how to incorporate group grammar techniques into a classroom activity. In the activity, students practice using the target grammar to do something they naturally enjoy: learning about each other.

  5. Modelling the Transfer of Radionuclides from Naturally Occurring Radioactive Material (NORM). Report of the NORM Working Group of EMRAS Theme 2

    International Nuclear Information System (INIS)

    2012-01-01

    This working group was established to improve the modelling of the transfer of radionuclides from residues containing naturally occurring radioactive material (NORM) for the purposes of radiological assessment. Almost all naturally occurring materials contain radionuclides from the primordial decay chains (for example, uranium-238, uranium-235, thorium-232 and their daughter products radium-226 and radium-228), plus some individual long-lived radionuclides such as potassium-40. Extraction and/or processing of minerals containing these materials results waste containing such radionuclides. Often the processing can enhance the concentration of the NORM in the waste as compared with the original material. The extraction and processing of minerals usually involves large volumes of material and the resulting waste is also present in large volumes which are usually left on the earth's surface. Human exposure to radionuclides from such waste piles can occur as a result of gaseous emanation from the waste (radon-222) or as a result of the leaching by rainfall of radionuclides from the waste into water courses and, possibly, food chains. There are a variety of situations involving NORM that require potential radiation doses to be assessed, they include: (1) surface storage of residues from the extraction and processing of minerals; (2) remediation of NORM-containing waste piles; and (3) the use of NORM-containing waste for backfilling, building materials, road construction etc. In all of these situations there is a need to understand the present and future behaviour of the radionuclides which may be released from NORM so that steps can be taken to ensure that humans are adequately protected from exposure to radiation. Because of the long-lived nature of many of the radionuclides, the assessments must be carried out over long times into the future. This is the first time that the modelling of NORM-containing radionuclides has been examined in this IAEA format and the working

  6. [Growth-regulating activity of N-benzyl- and O-benzyl-containing compounds belonging to a new group of synthetic analogues of natural auxins].

    Science.gov (United States)

    Gafurov, R G; Makhmutova, A A

    2005-01-01

    We studied the effect of benzylamine, benzyl alcohol, and their derivatives (constituting a new group of synthetic analogues of natural auxins) on rooting of leaf and stem cuttings, rhizogenesis and growth of barley plantlets and tomato seedlings, and tomato plant productivity. These compounds promoted rooting of leaf and stem bean cuttings, increased rhizogenic activity, and stimulated the development of root systems in barley and tomato seeds. The activity of the compounds studied was similar to that of standard substances (3-indoleacetic acid potassium salt and 2-naphthylacetic acid). The benzyl group attached to the oxygen or nitrogen atom was shown to be the smallest molecular structure which provided auxin activity of the compounds. Derivatives of benzyl alcohol containing the quaternary ammonium fragment possessed auxin and anti-gibberellin (retardant) properties. They were selected by chemical synthesis of low-molecular-weight bioregulators with desired properties (a combination of chemical fragments with complementary physiological activity in the molecule). Auxin and anti-gibberellin (retardant) activities produced a synergistic effect. Germination of seeds treated with these compounds was accompanied by a more significant increase in the weight and length of roots (compared to standard auxins). The rate of seedling establishment reached 100%. The development of fruits and accumulation of reserve nutrient substances were synchronized and accelerated after spraying vegetating plants with solutions of studied compounds. The synergistic effect underlay a significant increase in the amount and quality of the crop (e.g., tomatoes).

  7. Behavioural Responses of Yunnan Snub-Nosed Monkeys (Rhinopithecus bieti) to Tourists in a Provisioned Monkey Group in Baimaxueshan Nature Reserve.

    Science.gov (United States)

    Xia, Wancai; Ren, Baoping; Li, Yanhong; Hu, Jie; He, Xinming; Krzton, Ali; Li, Ming; Li, Dayong

    2016-01-01

    The appearance of tourists brings about behavioural changes in some primates. Primate behavioural responses to human activities can reflect their survival strategy. Little is known about how the behaviour of Rhinopithecus bieti changes in the presence of tourists. Here we provide the first detailed description of interactions between a provisioned group of R. bieti and tourists at Xiangguqing in Baimaxueshan Nature Reserve from July 2012 to June 2013. We found that R. bieti had different response rates to the 5 most common human actions (shout, photograph, offer food, clap, and wave). Results indicated that R. bieti expresses 10 behavioural reactions (threat, escape, vigilance, warning, panic, alliance, attack, foraging, approach, and staring) to tourists' actions. On the whole, most of the monkeys' responses were unfriendly or hostile; a small number were neutral and affiliative. Behavioural responses were also significantly different among the different age/sex classes. Immature individuals engaged in more affiliative behaviours than adult individuals, and adult males tended towards more hostile behaviours. The behaviour of R. bieti towards tourists showed both tension and adaptability. Scientific management of provisioned monkey groups and strict regulation of tourist behaviour is needed in order to protect the animals from the negative effects of tourism-related disturbance. © 2017 S. Karger AG, Basel.

  8. Increased concentrations of C-reactive protein but not high-mobility group box 1 in dogs with naturally occurring sepsis.

    Science.gov (United States)

    Karlsson, I; Wernersson, S; Ambrosen, A; Kindahl, H; Södersten, F; Wang, L; Hagman, R

    2013-11-15

    Sepsis is difficult to diagnose and remains a common mortality cause worldwide in both humans and animals. The uterine infection pyometra causes sepsis in more than half of affected dogs and therefore allows the natural physiological development of sepsis to be studied. To find a sepsis-specific biochemical marker that could be combined with conventional clinical criteria for a more robust and quick diagnosis of sepsis, we measured systemic concentrations of high-mobility group box 1 (HMGB1) in 23 healthy control dogs and in 27 dogs with pyometra, 74% of which had sepsis. We also measured concentrations of the major acute phase protein C-reactive protein (CRP) and an indicator for endotoxaemia, prostaglandin F2α metabolite (PGM) to assess the relative contribution of HMGB1 to the detection of systemic inflammation and endotoxaemia. We found that HMGB1 concentrations, in line with concentrations of CRP and PGM, were significantly increased in dogs with pyometra, and that concentrations of CRP, but not HMGB1, were significantly higher in dogs with sepsis compared to dogs without sepsis. Although serum HMGB1 did not differ between dogs with or without sepsis and was not correlated with either CRP or PGM concentrations, HMGB1 was correlated with the total white blood cell counts, suggesting an independent regulation and involvement in inflammation. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. A naturally occurring mutation in ropB suppresses SpeB expression and reduces M1T1 group A streptococcal systemic virulence.

    Directory of Open Access Journals (Sweden)

    Andrew Hollands

    Full Text Available Epidemiological studies of group A streptococcus (GAS have noted an inverse relationship between SpeB expression and invasive disease. However, the role of SpeB in the course of infection is still unclear. In this study we utilize a SpeB-negative M1T1 clinical isolate, 5628, with a naturally occurring mutation in the gene encoding the regulator RopB, to elucidate the role of RopB and SpeB in systemic virulence. Allelic exchange mutagenesis was used to replace the mutated ropB allele in 5628 with the intact allele from the well characterized isolate 5448. The inverse allelic exchange was also performed to replace the intact ropB in 5448 with the mutated allele from 5628. An intact ropB was found to be essential for SpeB expression. While the ropB mutation was shown to have no effect on hemolysis of RBC's, extracellular DNase activity or survival in the presence of neutrophils, strains with the mutated ropB allele were less virulent in murine systemic models of infection. An isogenic SpeB knockout strain containing an intact RopB showed similarly reduced virulence. Microarray analysis found genes of the SpeB operon to be the primary target of RopB regulation. These data show that an intact RopB and efficient SpeB production are necessary for systemic infection with GAS.

  10. Effects of enalapril maleate on survival of dogs with naturally acquired heart failure. The Long-Term Investigation of Veterinary Enalapril (LIVE) Study Group.

    Science.gov (United States)

    Ettinger, S J; Benitz, A M; Ericsson, G F; Cifelli, S; Jernigan, A D; Longhofer, S L; Trimboli, W; Hanson, P D

    1998-12-01

    To test the long-term effect of enalapril maleate treatment on progression of clinical signs of heart disease in dogs with moderate or severe naturally acquired heart failure associated with chronic degenerative mitral valvular disease (mitral regurgitation [MR]) or dilated cardiomyopathy (DCM). Prospective multicenter study. 110 dogs enrolled at 15 locations in the United States. All dogs enrolled in this study were maintained on their randomly allocated treatment regimen until death, treatment failure (deterioration of condition requiring additional medication), or termination of the study. All dogs entered in the study received standard heart failure treatment (furosemide with or without digoxin). Statistical analysis (log-rank test) was performed to compare the distribution of number of days in the study between dogs that received placebo tablets and dogs that received enalapril tablets. When dogs with MR and DCM were grouped together, mean number of days until treatment failure was significantly different between those receiving enalapril and those given placebo tablets (157.5 and 77.0 days, respectively). For dogs with MR, mean number of days until treatment failure was significantly different between those receiving enalapril and placebo tablets (159.5 and 86.6 days, respectively). Mean number of days until treatment failure among dogs with DCM receiving enalapril and placebo tablets was 142.8 and 56.5, respectively. Use of enalapril in combination with standard treatment (diuretics with or without digoxin) appears to be beneficial over an extended period, compared with standard treatment alone.

  11. Hypervariability generated by natural selection in an extracellular complement-inhibiting protein of serotype M1 strains of group A Streptococcus.

    Science.gov (United States)

    Stockbauer, K E; Grigsby, D; Pan, X; Fu, Y X; Mejia, L M; Cravioto, A; Musser, J M

    1998-03-17

    In many countries, M1 strains of the human pathogenic bacterium group A Streptococcus are the most common serotype recovered from patients with invasive disease episodes. Strains of this serotype express an extracellular protein that inhibits complement [streptococcal inhibitor of complement (Sic)] and is therefore believed to be a virulence factor. Comparative sequence analysis of the 915-bp sic gene in 165 M1 organisms recovered from diverse localities and infection types identified 62 alleles. Inasmuch as multilocus enzyme electrophoresis and pulsed-field gel electrophoresis previously showed that most M1 organisms represent a distinct streptococcal clone, the extent of sic gene polymorphism was unexpected. The level of polymorphism greatly exceeds that recorded for all other genes examined in serotype M1 strains. All insertions and deletions are in frame, and virtually all nucleotide substitutions alter the amino acid sequence of the Sic protein. These molecular features indicate that structural change in Sic is mediated by natural selection. Study of 70 strains recovered from two temporally distinct epidemics of streptococcal infections in the former East Germany found little sharing of Sic variants among strains recovered in the different time periods. Taken together, the data indicate that sic is a uniquely variable gene and provide insight into a potential molecular mechanism contributing to fluctuations in streptococcal disease frequency and severity.

  12. Bacterioplankton assemblages in coastal ponds reflect the influence of hydrology and geomorphological setting.

    Science.gov (United States)

    Huggett, Megan J; Kavazos, Christopher R J; Bernasconi, Rachele; Czarnik, Robert; Horwitz, Pierre

    2017-06-01

    The factors that shape microbial community assembly in aquatic ecosystems have been widely studied; yet it is still unclear how distinct communities within a connected landscape influence one another. Coastal lakes are recipients of, and thus are connected to, both marine and terrestrial environments. Thus, they may host microbial assemblages that reflect the relative degree of influence by, and connectivity to, either system. In order to address this idea, we interrogated microbial community diversity at 49 sites in seven ponds in two seasons in the Lake MacLeod basin, a system fed by seawater flowing inland through underground karst. Environmental and spatial variation within ponds explain <9% of the community structure, while identity of the pond that samples were taken from explains 50% of community variation. That is, ponds each host distinct assemblages despite similarities in size, environment and position in the landscape, indicating a dominant role for local species sorting. The ponds contain a substantial amount of previously unknown microbial taxa, reflecting the unusual nature of this inland system. Rare marine taxa, possibly dispersed from seawater assemblages via the underground karst connection, are abundant within the inland system, suggesting an important role for regional dispersal within the metacommunities. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Excess labile carbon promotes the expression of virulence factors in coral reef bacterioplankton

    KAUST Repository

    Cardenas, Anny

    2017-09-12

    Coastal pollution and algal cover are increasing on many coral reefs, resulting in higher dissolved organic carbon (DOC) concentrations. High DOC concentrations strongly affect microbial activity in reef waters and select for copiotrophic, often potentially virulent microbial populations. High DOC concentrations on coral reefs are also hypothesized to be a determinant for switching microbial lifestyles from commensal to pathogenic, thereby contributing to coral reef degradation, but evidence is missing. In this study, we conducted ex situ incubations to assess gene expression of planktonic microbial populations under elevated concentrations of naturally abundant monosaccharides (glucose, galactose, mannose, and xylose) in algal exudates and sewage inflows. We assembled 27 near-complete (>70%) microbial genomes through metagenomic sequencing and determined associated expression patterns through metatranscriptomic sequencing. Differential gene expression analysis revealed a shift in the central carbohydrate metabolism and the induction of metalloproteases, siderophores, and toxins in Alteromonas, Erythrobacter, Oceanicola, and Alcanivorax populations. Sugar-specific induction of virulence factors suggests a mechanistic link for the switch from a commensal to a pathogenic lifestyle, particularly relevant during increased algal cover and human-derived pollution on coral reefs. Although an explicit test remains to be performed, our data support the hypothesis that increased availability of specific sugars changes net microbial community activity in ways that increase the emergence and abundance of opportunistic pathogens, potentially contributing to coral reef degradation.

  14. Natural history and parental experience of children with trisomy 18 based on a questionnaire given to a Japanese trisomy 18 parental support group.

    Science.gov (United States)

    Kosho, Tomoki; Kuniba, Hideo; Tanikawa, Yuko; Hashimoto, Yoko; Sakurai, Hiroko

    2013-07-01

    We conducted a questionnaire-based study in collaboration with a Japanese trisomy 18 parental support group. Sixty-five children (female, 68%) with full trisomy 18 were evaluated. Diagnosis was made prenatally in 17% (11/65) and 57% (37/65) were born following a cesarean. The mean gestational age at delivery was 38 weeks and 6 days, and the mean birth weight was 1,920 g (-2.6SD). A total of 51% (24/47) of children had apneic episodes. Thirteen children experienced generalized seizures, and a minority was seizure-free with medication. Parents of 36% (18/50) of children were offered intensive treatment. A total of 45% (27/60) of children received intermittent mandatory ventilation, which was weaned off in half of them. Nine had surgeries, including esophageal atresia/omphalocele correction, cardiac surgery, and tracheostomy. A total of 15% (8/55) were fed fully orally, and 45% (29/64) were discharged home. Slow but constant psychomotor development was observed, and in four long-term survivors over 10 years, two walked unassisted. Factors significantly associated with survival over 1 year included diagnosis after birth, absence of prematurity, heavier birth weight, absence of esophageal atresia, extubation, ability to feed orally without medical assistance, and home discharge. Parents appeared to be positive about caring for their children, and the children seemed to interact with parents and siblings as long as they lived, resulting in quality family time. The family point of view, as well as knowledge of natural history, should be considered when policy statements about the care of children with trisomy 18 are made. Copyright © 2013 Wiley Periodicals, Inc.

  15. Linking Activity and Function to Ecosystem Dynamics in a Coastal Bacterioplankton Community

    Directory of Open Access Journals (Sweden)

    Scott Michael Gifford

    2014-04-01

    Full Text Available For bacterial communities containing hundreds to thousands of distinct populations, connecting functional processes and environmental dynamics at high taxonomic resolution has remained challenging. Here we use the expression of ribosomal proteins (%RP as a proxy for in situ activity of 200 taxa within 20 metatranscriptomic samples in a coastal ocean time series encompassing both seasonal variability and diel dynamics. %RP patterns grouped the taxa into seven activity clusters with distinct profiles in functional gene expression and correlations with environmental gradients. Clusters 1-3 had their highest potential activity in the winter and fall, and included some of the most active taxa, while Clusters 4-7 had their highest potential activity in the spring and summer. Cluster 1 taxa were characterized by gene expression for motility and complex carbohydrate degradation (dominated by Gammaproteobacteria and Bacteroidetes, and Cluster 2 taxa by transcription of genes for amino acid and aromatic compound metabolism and aerobic anoxygenic phototrophy (Roseobacter. Other activity clusters were enriched in transcripts for proteorhodopsin and methylotrophy (Cluster 4; SAR11 and methylotrophs, photosynthesis and attachment (Clusters 5 and 7; Synechococcus, picoeukaryotes, Verucomicrobia, and Planctomycetes, and sulfur oxidation (Cluster 7; Gammaproteobacteria. The seasonal patterns in activity were overlain, and sometimes obscured, by large differences in %RP over shorter day-night timescales. Seventy-eight taxa, many of them heterotrophs, had a higher %RP activity index during the day than night, indicating strong diel activity at this coastal site. Emerging from these taxonomically- and time-resolved estimates of in situ microbial activity are predictions of specific ecological groupings of microbial taxa in a dynamic coastal environment.

  16. Morphology and LPS content for the estimation of marine bacterioplankton biomass in the Ionian Sea

    Directory of Open Access Journals (Sweden)

    Rosabruna La Ferla

    2004-03-01

    Full Text Available The abundance, morphotypes and biomass of the bacterial assemblages were investigated in the Ionian Sea by using two different methods: the epifluorescent microscopy technique for enumerating and sizing bacterial cells, and the determination of bacterial lipopolysaccharides (LPS. Five bacterial morphotypes were distinguished: cocci, rods, coccobacilli, vibrios and spirillae. The proportions of cocci were higher than those of other morphotypes at every depth, ranging from 39% to 73%. Both rod-shaped bacteria and coccobacilli were homogenously distributed in the water column, while the proportions of vibrios were rather variable. Spirillae occurred only in surface samples and disappeared below 100 m. The two methodologies were compared: LPS concentrations showed a highly significant correlation with the bacterial numbers (P< 0.01; n= 88; r= 0.68, but not with biovolumes, and different ratios between LPS concentrations and bacterial volumes were recorded for the photic and aphotic zones (3.11 ± 1.35 and 0.96 ± 0.37 ng LPS per µm3 respectively. LPS-derived cell carbon content on average was 23 fg C cell-1, similar to the C amount derived by mean cell biovolume (19 fg C cell-1 and the biomass from two highly correlated methods (P< 0.01; n= 95; r= 0.59. Our results confirm that the widely used factor of 20 fg C cell-1 (Lee and Furhman, 1987 should be plausible for studying the biomass of the natural microbial populations in the study area. Nevertheless, the wide variability of the cell size classes, also along the whole water columns, questions the applicability of a constant conversion factor for all the marine ecosystems. Consequently, locally derived biomass estimates of bacteria are essential in order to obtain an accurate evaluation of the bacterial role in biogeochemical cycles.

  17. Experimental incubations elicit profound changes in community transcription in OMZ bacterioplankton.

    Directory of Open Access Journals (Sweden)

    Frank J Stewart

    Full Text Available Sequencing of microbial community RNA (metatranscriptome is a useful approach for assessing gene expression in microorganisms from the natural environment. This method has revealed transcriptional patterns in situ, but can also be used to detect transcriptional cascades in microcosms following experimental perturbation. Unambiguously identifying differential transcription between control and experimental treatments requires constraining effects that are simply due to sampling and bottle enclosure. These effects remain largely uncharacterized for "challenging" microbial samples, such as those from anoxic regions that require special handling to maintain in situ conditions. Here, we demonstrate substantial changes in microbial transcription induced by sample collection and incubation in experimental bioreactors. Microbial communities were sampled from the water column of a marine oxygen minimum zone by a pump system that introduced minimal oxygen contamination and subsequently incubated in bioreactors under near in situ oxygen and temperature conditions. Relative to the source water, experimental samples became dominated by transcripts suggestive of cell stress, including chaperone, protease, and RNA degradation genes from diverse taxa, with strong representation from SAR11-like alphaproteobacteria. In tandem, transcripts matching facultative anaerobic gammaproteobacteria of the Alteromonadales (e.g., Colwellia increased 4-13 fold up to 43% of coding transcripts, and encoded a diverse gene set suggestive of protein synthesis and cell growth. We interpret these patterns as taxon-specific responses to combined environmental changes in the bioreactors, including shifts in substrate or oxygen availability, and minor temperature and pressure changes during sampling with the pump system. Whether such changes confound analysis of transcriptional patterns may vary based on the design of the experiment, the taxonomic composition of the source community

  18. Dissolved Compounds Excreted by Copepods Reshape the Active Marine Bacterioplankton Community Composition

    Directory of Open Access Journals (Sweden)

    Valentina P. Valdés

    2017-11-01

    Full Text Available Copepods are important suppliers of bioreactive compounds for marine bacteria through fecal pellet production, sloppy feeding, and the excretion of dissolved compounds. However, the interaction between copepods and bacteria in the marine environment is poorly understood. We determined the nitrogen and phosphorus compounds excreted by copepods fed with two natural size-fractionated diets (<20- and 20–150-μm in the upwelling zone of central/southern Chile in late summer and spring. We then assessed the biogeochemical response of the bacterial community and its structure, in terms of total and active cells, to enrichment by copepod-excreted dissolved compounds. Results revealed that copepods actively excreted nitrogen and phosphorus compounds, mainly in the form of ammonium and dissolved organic phosphorus (DOP, reaching excretion rates of 2.6 and 0.05 μmol L−1h−1, respectively. In both periods, the maximum excretion rates were associated with the 20–150-μm size fraction, but particularly during spring, when a higher organic matter quality was observed in excretion products compared to late summer. There were higher excretion rates of dissolved free amino acids (DFAAs from copepods fed with the <20-μm size fraction, mainly histidine (HIS in late summer and glutamic acid (GLU in spring. A shift in the composition of the active bacterial community was observed between periods and treatments, which was associated with the response of the common seawater surface phyla Proteobacteria and Bacteroidetes. The specific bacterial activity (16S rRNA:rDNA suggested a different response to the two size-fractionated diets. In late summer, Betaproteobacteria and Bacteroidetes were stimulated by the treatment enriched with excretion products derived from the 20–150-μm and <20-μm size fractions, respectively. In spring, Alphaproteobacteria were active in the treatment enriched with the excretion products of copepods fed with the <20-μm size

  19. Pollution Impacts on Bacterioplankton Diversity in a Tropical Urban Coastal Lagoon System

    Science.gov (United States)

    Salloto, Gigliola R. B.; Cardoso, Alexander M.; Coutinho, Felipe H.; Pinto, Leonardo H.; Vieira, Ricardo P.; Chaia, Catia; Lima, Joyce L.; Albano, Rodolpho M.; Martins, Orlando B.; Clementino, Maysa M.

    2012-01-01

    Despite a great number of published studies addressing estuarine, freshwater and marine bacterial diversity, few have examined urban coastal lagoons in tropical habitats. There is an increasing interest in monitoring opportunistic pathogens as well as indigenous microbial community members in these water bodies by current molecular and microbiological approaches. In this work, bacterial isolates were obtained through selective plate dilution methods to evaluate antibiotic resistances. In addition, 16S rRNA gene libraries were prepared from environmental waters and mixed cultures grown in BHI medium inoculated with Jacarepaguá lagoon waters. Denaturing gradient gel electrophoresis (DGGE) analyses showed distinct community profiles between environmental communities from each studied site and their cultured counterparts. A total of 497 bacterial sequences were analyzed by MOTHUR, yielding 245 operational taxonomic units (OTUs) grouped at 97% similarity. CCA diagrams showcased how several environmental variables affect the distribution of 18 bacterial orders throughout the three distinct habitats. UniFrac metrics and Venn diagrams revealed that bacterial communities retrieved through each experimental approach were significantly different and that only one OTU, closely related to Vibrio cholerae, was shared between them. Potentially pathogenic bacteria were isolated from most sampled environments, fifty percent of which showed antibiotic resistance. PMID:23226484

  20. Pollution impacts on bacterioplankton diversity in a tropical urban coastal lagoon system.

    Directory of Open Access Journals (Sweden)

    Gigliola R B Salloto

    Full Text Available Despite a great number of published studies addressing estuarine, freshwater and marine bacterial diversity, few have examined urban coastal lagoons in tropical habitats. There is an increasing interest in monitoring opportunistic pathogens as well as indigenous microbial community members in these water bodies by current molecular and microbiological approaches. In this work, bacterial isolates were obtained through selective plate dilution methods to evaluate antibiotic resistances. In addition, 16S rRNA gene libraries were prepared from environmental waters and mixed cultures grown in BHI medium inoculated with Jacarepaguá lagoon waters. Denaturing gradient gel electrophoresis (DGGE analyses showed distinct community profiles between environmental communities from each studied site and their cultured counterparts. A total of 497 bacterial sequences were analyzed by MOTHUR, yielding 245 operational taxonomic units (OTUs grouped at 97% similarity. CCA diagrams showcased how several environmental variables affect the distribution of 18 bacterial orders throughout the three distinct habitats. UniFrac metrics and Venn diagrams revealed that bacterial communities retrieved through each experimental approach were significantly different and that only one OTU, closely related to Vibrio cholerae, was shared between them. Potentially pathogenic bacteria were isolated from most sampled environments, fifty percent of which showed antibiotic resistance.

  1. Spatial diversity of bacterioplankton communities in surface water of northern South China Sea.

    Directory of Open Access Journals (Sweden)

    Jialin Li

    Full Text Available The South China Sea is one of the largest marginal seas, with relatively frequent passage of eddies and featuring distinct spatial variation in the western tropical Pacific Ocean. Here, we report a phylogenetic study of bacterial community structures in surface seawater of the northern South China Sea (nSCS. Samples collected from 31 sites across large environmental gradients were used to construct clone libraries and yielded 2,443 sequences grouped into 170 OTUs. Phylogenetic analysis revealed 23 bacterial classes with major components α-, β- and γ-Proteobacteria, as well as Cyanobacteria. At class and genus taxon levels, community structure of coastal waters was distinctively different from that of deep-sea waters and displayed a higher diversity index. Redundancy analyses revealed that bacterial community structures displayed a significant correlation with the water depth of individual sampling sites. Members of α-Proteobacteria were the principal component contributing to the differences of the clone libraries. Furthermore, the bacterial communities exhibited heterogeneity within zones of upwelling and anticyclonic eddies. Our results suggested that surface bacterial communities in nSCS had two-level patterns of spatial distribution structured by ecological types (coastal VS. oceanic zones and mesoscale physical processes, and also provided evidence for bacterial phylogenetic phyla shaped by ecological preferences.

  2. The Temporal Dynamics of Coastal Phytoplankton and Bacterioplankton in the Eastern Mediterranean Sea.

    Directory of Open Access Journals (Sweden)

    Ofrat Raveh

    Full Text Available This study considers variability in phytoplankton and heterotrophic bacterial abundances and production rates, in one of the most oligotrophic marine regions in the world-the Levantine Basin. The temporal dynamics of these planktonic groups were studied in the coastal waters of the southeastern Mediterranean Sea approximately every two weeks for a total of two years. Heterotrophic bacteria were abundant mostly during late summer and midwinter, and were positively correlated with bacterial production and with N2 fixation. Based on size fractionating, picophytoplankton was abundant during the summer, whereas nano-microphytoplankton predominated during the winter and early spring, which were also evident in the size-fractionated primary production rates. Autotrophic abundance and production correlated negatively with temperature, but did not correlate with inorganic nutrients. Furthermore, a comparison of our results with results from the open Levantine Basin demonstrates that autotrophic and heterotrophic production, as well as N2 fixation rates, are considerably higher in the coastal habitat than in the open sea, while nutrient levels or cell abundance are not different. These findings have important ecological implications for food web dynamics and for biological carbon sequestration in this understudied region.

  3. The divided mind of a disbeliever: Intuitive beliefs about nature as purposefully created among different groups of non-religious adults.

    Science.gov (United States)

    Järnefelt, Elisa; Canfield, Caitlin F; Kelemen, Deborah

    2015-07-01

    Do non-religious adults - despite their explicit disavowal of religious beliefs - have a tacit tendency to view nature as purposefully created by some being? This question was explored in three online studies using a speeded judgment procedure, which assessed disbelievers in two different Western cultures (United States and Finland). Despite strong performance on control trials, across all three studies non-religious individuals displayed a default bias to increasingly judge pictures of natural phenomena as "purposefully made by some being" under processing constraints. Personal beliefs in the supernatural agency of nature ("Gaia beliefs") consistently predicted this tendency. However, beliefs in nature as purposefully made by some being persisted even when such secular agency beliefs were controlled. These results suggest that the tendency to view nature as designed is rooted in evolved cognitive biases as well as cultural socialization. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Close Link Between Harmful Cyanobacterial Dominance and Associated Bacterioplankton in a Tropical Eutrophic Reservoir

    Directory of Open Access Journals (Sweden)

    Iame A. Guedes

    2018-03-01

    Full Text Available Cyanobacteria tend to become the dominant phytoplankton component in eutrophic freshwater environments during warmer seasons. However, general observations of cyanobacterial adaptive advantages in these circumstances are insufficient to explain the prevalence of one species over another in a bloom period, which may be related to particular strategies and interactions with other components of the plankton community. In this study, we present an integrative view of a mixed cyanobacterial bloom occurring during a warm, rainy period in a tropical hydropower reservoir. We used high-throughput sequencing to follow temporal shifts in the dominance of cyanobacterial genera and shifts in the associated heterotrophic bacteria community. The bloom occurred during late spring-summer and included two distinct periods. The first period corresponded to Microcystis aeruginosa complex (MAC dominance with a contribution from Dolichospermum circinale; this pattern coincided with high water retention time and low transparency. The second period corresponded to Cylindrospermopsis raciborskii and Synechococcus spp. dominance, and the reservoir presented lower water retention time and higher water transparency. The major bacterial phyla were primarily Cyanobacteria and Proteobacteria, followed by Actinobacteria, Bacteroidetes, Verrucomicrobia, and Planctomycetes. Temporal shifts in the dominance of cyanobacterial genera were not only associated with physical features of the water but also with shifts in the associated heterotrophic bacteria. The MAC bloom was associated with a high abundance of Bacteroidetes, particularly Cytophagales. In the second bloom period, Planctomycetes increased in relative abundance, five Planctomycetes OTUs were positively correlated with Synechococcus or C. raciborskii OTUs. Our results suggest specific interactions of the main cyanobacterial genera with certain groups of the heterotrophic bacterial community. Thus, considering biotic

  5. On the significance of natural gas with regard to tomorrow's customer target group; Zur Bedeutung von Erdgas in der Kundenzielgruppe von morgen

    Energy Technology Data Exchange (ETDEWEB)

    Halstrup, Dominik [Hochschule Osnabrueck (Germany). Professur fuer BWL und Strategisches Management; Groeblinghoff, Sebastian [EVU, Essen (Germany); Walsh, Gianfranco [Koblenz Univ. (Germany). Inst. fuer Management

    2011-10-15

    Competition between the energy carriers in Germany's heating market has become harsher over the past years and is expected to grow still further. Successful customer acquisition and long-term customer retention will become increasingly important for natural gas supply companies. For this reason decision makers at public utilities that have a significant share of natural gas in their sales portfolio should have the foresight to ask themselves what sentiment tomorrow's home and house owners will have towards natural gas as an energy product as well as towards their company.

  6. Task Group 7B: Cellular and Molecular Mechanisms of Biological Aging: The Roles of Nature, Nurture and Chance in the Maintenance of Human Healthspan

    Energy Technology Data Exchange (ETDEWEB)

    Weier, Heinz-Ulrich; Arya, Suresh; Grant, Christine; Miller, Linda; Ono, Santa Jeremy; Patil, Chris; Shay, Jerry; Topol, Eric; Torry, Michael; Weier, Heinz-Ulrich G.; Tse, Iris; Lin, Su-Ju; Miller, Richard

    2007-11-14

    The degree to which an individual organism maintains healthspan and lifespan is a function of complex interactions between genetic inheritance ('nature'), environment, including cultural inheritance (nurture) and stochastic events ('luck' or 'chance'). This task group will focus upon the role of chance because it is so poorly understood and because it appears to be of major importance in the determination of individual variations in healthspan and lifespan within species. The major factor determining variations in healthspan and lifespan between species is genetic inheritance. Broader aspects of cellular and molecular mechanisms of biological aging will also be considered, given their importance for understanding the cellular and molecular basis of successful aging. The task force will consider the cellular and molecular basis for nature, nurture and chance in healthspan and life span determination. On the basis of comparisons between identical and non-identical twins, geneticists have estimated that genes control no more than about a quarter of the inter-individual differences in lifespan (Herskind 1996). Twin studies of very old individuals, however, show substantially greater genetic contributions to Healthspan (McClearn 2004; Reed 2003). The environment clearly plays an important role in the length and the quality of life. Tobacco smoke, for example has the potential to impact upon multiple body systems in ways that appear to accelerate the rates at which those systems age (Bernhard 2007). To document the role of chance events on aging, one must rigorously control both the genetic composition of an organism and its environment. This has been done to a remarkable degree in a species of nematodes, Caenorhabditis elegans (Vanfleteren 1998). The results confirm hundreds of previous studies with a wide range of species, especially those with inbred rodents housed under apparently identical but less well controlled environments. One

  7. DiGIR1 and NaGIR1: naturally occurring group I-like ribozymes with unique core organization and evolved biological role

    DEFF Research Database (Denmark)

    Johansen, Steinar; Einvik, Christer; Nielsen, Henrik

    2002-01-01

    the characteristic P1 segment present in all group I splicing ribozymes, it has a novel core organization, and it catalyses two site-specific hydrolytic cleavages rather than splicing. DiGIR1 and NaGIR1 appear to have originated from eubacterial group I introns in order to fulfil a common biological challenge...

  8. Seasonal and spatial distribution of Bacterioplankton in a fluvial-lagunar system of a tropical region: density, biomass, cellular volume and morphologic variation

    Directory of Open Access Journals (Sweden)

    Magnólia Fernandes Florêncio de Araújo

    2008-02-01

    Full Text Available The temporal and spatial fluctuations of Bacterioplankton in a fluvial-lagunar system of a tropical region (Pitimbu River and Jiqui Lake, RN were studied during the dry and the rainy periods. The bacterial abundance varied from 2.67 to 5.1 Cells10(7mL-1 and did not show a typical temporal variation, presenting only small oscillations between the rainy and the dry periods. The bacterial biomass varied from 123 µgC L-1 to 269 µgC L-1 in the sampling sites and the average cellular volume varied from 0.12 to 0.54µm³, showing a predominance of the rods. The temperature showed a positive correlation with the cellular volume of the rods (R=0.55; p=0.02 and vibrio (R=0.53; p=0.03. Significant spatial differences of biomass (Mann Whitney: p=0.01 and cellular volume of the morphotypes (Mann Whitney: p=0.003 were found between the sampling sites. The strong positive correlations of the water temperature and oxygen with bacterioplankton showed a probable high bacterial activity in this system.A variação temporal e espacial do bacterioplâncton em um sistema fluvial-lagunar de região tropical foi estudada em períodos seco e chuvoso. As médias da abundância bacteriana variaram de 2,67 a 5,1 x 10(7 e não exibiram uma variação temporal marcante, tendo apresentado apenas pequenas oscilações entre os períodos chuvoso e seco. A biomassa bacteriana variou de 123 µg C L-1 a 269 µg C L-1 entre os locais de coleta e o volume celular médio de 0,12µm³ a 0,54µm³, ocorrendo predominância de bacilos. A temperatura mostrou correlação positiva com o volume celular de bacilos (R=0,55; p=0,02 e de vibriões (R=0,53; p=0,03. Foram encontradas diferenças espaciais significativas de biomassa (Mann Whitney: p=0,01 e volume celular dos morfotipos (Mann Whitney: p= 0,003, entre os locais de coleta. As fortes correlações positivas da temperatura da água e do oxigênio, com o bacterioplâncton, são sugestivas de uma provavelmente elevada atividade

  9. Influence of top-down and bottom-up manipulations on the R-BT065 subcluster of Betaproteobacteria, an abundant group in bacterioplankton of a freshwater reservoir

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Horňák, Karel; Jezbera, Jan; Mašín, Michal; Nedoma, Jiří; Gasol, J. M. .; Schauer, M.

    2005-01-01

    Roč. 71, č. 5 (2005), s. 2381-2390 ISSN 0099-2240 R&D Projects: GA ČR(CZ) GA206/05/0007; GA ČR(CZ) GA206/02/0003 Grant - others:CSIC(ES) DGICYT REN2001-2120/MAR; EU(XE) EVK3-CT-2002-00078; Austrian Science Foundation(AT) P15655 Institutional research plan: CEZ:AV0Z60170517 Keywords : reservoir * top-down and bottom-up control * microbial food webs * bacterivory * bacterial community composition Subject RIV: EE - Microbiology, Virology Impact factor: 3.818, year: 2005

  10. Natural-orifice transluminal endoscopic surgery (NOTES) in Europe: summary of the working group reports of the Euro-NOTES meeting 2010

    DEFF Research Database (Denmark)

    Meining, A; Feussner, H; Swain, P

    2011-01-01

    collaboration and indications, robotics and platforms, and matters related to training and education. This review summarizes consensus statements of the working groups to give an overview of what has been achieved so far and what might be relevant for research related to NOTES in the near future....... formed, consisting of participants with varying scientific and medical backgrounds. Each group was assigned to an important topic: the correct strategy for dealing with bacterial contamination and related complications, the question of the ideal entry point and secure closure, interdisciplinary...

  11. Genetic Diversity, Natural Selection and Haplotype Grouping of Plasmodium knowlesi Gamma Protein Region II (PkγRII): Comparison with the Duffy Binding Protein (PkDBPαRII).

    Science.gov (United States)

    Fong, Mun Yik; Rashdi, Sarah A A; Yusof, Ruhani; Lau, Yee Ling

    2016-01-01

    Plasmodium knowlesi is a simian malaria parasite that has been reported to cause malaria in humans in Southeast Asia. This parasite invades the erythrocytes of humans and of its natural host, the macaque Macaca fascicularis, via interaction between the Duffy binding protein region II (PkDBPαRII) and the Duffy antigen receptor on the host erythrocytes. In contrast, the P. knowlesi gamma protein region II (PkγRII) is not involved in the invasion of P. knowlesi into humans. PkγRII, however, mediates the invasion of P. knowlesi into the erythrocytes of M. mulata, a non-natural host of P. knowlesi via a hitherto unknown receptor. The haplotypes of PkDBPαRII in P. knowlesi isolates from Peninsular Malaysia and North Borneo have been shown to be genetically distinct and geographically clustered. Also, the PkDBPαRII was observed to be undergoing purifying (negative) selection. The present study aimed to determine whether similar phenomena occur in PkγRII. Blood samples from 78 knowlesi malaria patients were used. Forty-eight of the samples were from Peninsular Malaysia, and 30 were from Malaysia Borneo. The genomic DNA of the samples was extracted and used as template for the PCR amplification of the PkγRII. The PCR product was cloned and sequenced. The sequences obtained were analysed for genetic diversity and natural selection using MEGA6 and DnaSP (version 5.10.00) programmes. Genetic differentiation between the PkγRII of Peninsular Malaysia and North Borneo isolates was estimated using the Wright's FST fixation index in DnaSP (version 5.10.00). Haplotype analysis was carried out using the Median-Joining approach in NETWORK (version 4.6.1.3). A total of 78 PkγRII sequences was obtained. Comparative analysis showed that the PkγRII have similar range of haplotype (Hd) and nucleotide diversity (π) with that of PkDBPαRII. Other similarities between PkγRII and PkDBPαRII include undergoing purifying (negative) selection, geographical clustering of haplotypes

  12. Natural History of the Slave Making Ant, Polyergus lucidus, Sensu lato in Northern Florida and Its Three Formica pallidefulva Group Hosts

    Science.gov (United States)

    King, Joshua R.; Trager, James C.

    2007-01-01

    Slave making ants of the Polyergus lucidus Mayr (Hymenoptera: Formicidae) complex enslave 3 different Formica species, Formica archboldi, F. dolosa, and F. pallidefalva, in northern Florida. This is the first record of presumed P. lucidus subspecies co-occurring with and enslaving multiple Formica hosts in the southern end of their range. The behavior, colony sizes, body sizes, nest architecture, and other natural history observations of Polyergus colonies and their Formica hosts are reported. The taxonomic and conservation implications of these observations are discussed. PMID:20345317

  13. The frequency and spectrum of congenital anomalies in natural family planning users in South America: no increase in a case-control study. NFP-ECLAMC Group. Natural Family Planning. Latin-American Collaborative Study of Congenital Malformations.

    Science.gov (United States)

    Castilla, E E; Lopez-Camelo, J S; da Graça Dutra, M; Queenan, J T; Simpson, J L

    1997-12-01

    Users of natural family planning (NFP) practice periodic abstinence, leading many to reason that such couples should show increased anomalies in offspring as a result of fertilization involving aging gametes. In an effort to complement our NFP cohort study, we currently conducted a case-control study in the same region (South America) in which the largest number of cases have been recruited for our cohort NFP study. During 1992-94, 5324 case-control pairs of mothers were interviewed during the immediate postpartum period in 18 maternity hospitals participating in the Latin-American Collaborative Study of Congenital Malformations: ECLAMC (Spanish acronym for Latin-American Collaborative Study of Congenital Malformations). Natural family planning (NFP) usage was recorded in 6% of mothers in the ECLAMC sample studied (n = 10,648). Overall, no significant differences in frequency of NFP usage were observed between malformed cases (349/5324 = 6.6%) and normal controls (303/5324 = 5.7%) (chi 2 = 3.3; df = 1; p > 0.05). No significant differences in sex ratios were observed between children of NFP user and non-user mothers. Of special interest is the lack of association between NFP and Down syndrome, the sentinel phenotype for the hypothesis of delayed fertilization (aging gametes).

  14. The internationalisation of Spanish family firms through business groups: Factors affecting the profitability, and the moderating effect of the family nature of the Spanish business

    Directory of Open Access Journals (Sweden)

    M. Carmen Pérez-López

    2018-01-01

    The results of this study could help to clarify an issue of some significance in professional and academic circles. Both owners and managers of family businesses can use these research findings to better understand how certain characteristics of business group management could affect their performance and the success of the internationalisation process.

  15. Natural resources as an area of protection in LCA - outcomes of the discussion by the working group on resources within the UNEP-SETAC Life Cycle Initiative

    DEFF Research Database (Denmark)

    Sonderegger, T.; Fantke, Peter; Dewulf, J.

    2016-01-01

    The topic of resources as an area of protection (AoP) in life cycle assessment (LCA) is being discussed within an expert group under the umbrella of the Life Cycle Initiative by the United Nations Environment Programme (UNEP) and the Society for Environmental Toxicology and Chemistry (SETAC...

  16. Effect of the pollution level on the functional bacterial groups aiming at degrading bisphenol A and nonylphenol in natural biofilms of an urban river.

    Science.gov (United States)

    Cai, Wei; Li, Yi; Wang, Peifang; Niu, Lihua; Zhang, Wenlong; Wang, Chao

    2016-08-01

    Bisphenol A (BPA) and 4-nonylphenol (NP) are ubiquitous pollutants with estrogenic activity in aquatic environment and have attracted global concern due to their disruption of endocrine systems. This study investigated the spatial distribution characteristics of the bacterial groups involved in the degradation of BPA and NP within biofilms in an urban river using terminal restriction fragment length polymorphism based on 16S rRNA gene sequences. The effects of the pollution level and water parameters on these groups were also assessed. Hierarchical cluster analysis grouped the sampling sites into three clusters reflecting their varying nutrient pollution levels of relatively slight pollution (SP), moderate pollution (MP), and high pollution (HP) based on water quality data and Environmental Quality Standard for Surface Water of China (GB3838-2002). The BPA and NP concentration in river water ranged from 0.8 to 77.5 and 10.2 to 162.9 ng L(-1), respectively. Comamonadaceae, Pseudomonadaceae, Alcaligenaceae, Bacillaceae, Sphingomonadacea, Burkholderiaceae, and Rhizobiaceae were the dominant bacterial taxa involved in BPA and NP degradation, comprising an average of 9.8, 8.1, 7.6, 6.7, 6.2, 4.1, and 2.8 % of total sequences, respectively. The total abundance of these groups showed a slight upward trend and subsequently rapidly decreased with increasing pollution levels. The average proportion of Comamonadaceae in MP river sections was almost 1.5-2 times than that in SP or HP one. The distribution of functional groups was found related to environmental variables, especially pH, conductivity, ammonium nitrogen (NH3-N), and BPA. The abundance of Comamonadaceae and Rhizobiaceae was both closely related to higher values of pH and conductivity as well as lower concentrations of NP and BPA. Alcaligenaceae and Pseudomonadaceae were associated with higher concentrations of TP and CODMn and inversely correlated with DO concentration. This study might provide effective data on

  17. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  18. Pluralising Nature

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2017-01-01

    Denmark is recognised for its democratic approach to planning, and for the idea of planning for the common good. This interest in the common good and in common values also seems to be reflected in the way that the restoration of nature is planned and managed, suggesting that there is one common...... “nature” that everyone can agree on. But nature restoration is far from being an unproblematic undertaking. As with any other type of heritage production, it can be the source of dissonance. As exemplified by the Skjern River Restoration Project, one perception of a landscape and its value as “nature” can...... suppress other valid perceptions, in conflict with the need for different groups of people to be able to identify with the same territory. However, planning for the common good, in the case of nature restoration, does not necessarily mean planning for one common nature. Understanding and working...

  19. Natural endocrine profiles of the group-living skunk anemonefish Amphiprion akallopisos in relation to their size-based dominance hierarchy.

    Science.gov (United States)

    Mills, S C; O'Donnell, J L; Bernardi, G; Beldade, R

    2018-03-01

    Group-living animals commonly display differences in behaviour, physiology and endocrine profiles between conspecifics within the group, which are tightly linked to reproduction. Teleosts exhibit a variety of social systems, where social status, as well as sex, has been linked to different androgen and oestrogen profiles. Levels of gonadal androgen and oestrogen were investigated as a function of sex and position in a social hierarchy in free-living individuals of the skunk anemonefish Amphiprion akallopisos, a protandrous pomacentrid fish with a size-based dominance hierarchical social system. Plasma levels of 11-ketotestosterone (11-KT), testosterone (T) and 17β-oestradiol (E 2 ), as well as conversion ratios from T, were measured by ELISA from 111 individuals along a linear hierarchy from 38 social groups in the wild. Blood plasma levels of 11-KT and E 2 showed sex differences, being higher in males and females respectively as expected based on their role as the major androgen and oestrogen in fish reproduction. However, no sex differences were found for T, which may represent its role in territorial defence or simply as a precursor for the synthesis of 11-KT and E 2 . In terms of the hierarchical social system within males, 11-KT levels decline as the hierarchy is descended, which may represent their decreasing reproductive opportunity, as well as the decreasing levels of aggression towards males lower in the hierarchy. In summary, the size-based dominance hierarchy is associated with distinct steroid levels of 11-KT and E 2 between individual free-living A. akallopisos that closely resemble those of species in which breeding individuals suppress reproduction of conspecifics lower in the hierarchy. © 2018 The Fisheries Society of the British Isles.

  20. On the nature of the electronic effect of multiple hydroxyl groups in the 6-membered ring - the effects are additive but steric hindrance plays a role too

    DEFF Research Database (Denmark)

    Pedersen, Christian Marcus; Bols, Mikael

    2017-01-01

    Research during the last two decades has shown a remarkable directional component of the substituent effects of hydroxy groups, which has a profound effect on the properties of hydroxylated compounds such as carbohydrates. While the epimerisation of a single hydroxyl function is well studied...... synthesized and their pKa and conformation were studied. The results show that the large difference in the electronic effect between the axial and equatorial hydroxyls is partially cancelled by counteracting steric hindrance from 1,3-diaxial interactions. Hydrogen bonding does not appear to play any role...

  1. The bourgeoisie framed: Mafalda and its group criticize elements of the bourgeois society (the naturalization of the differences, the inhumanuzation and the competition in the History class

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Rebuá Oliveira

    2012-08-01

    Full Text Available The purpose of this work, from a marxist point of view, is to think about the possibility in criticizing the bourgeosie society in History classes, to set up colectively, at last, anti-hegemonic reality readings. Based upon Gramsci concept of hegemony and on anti-hegemony notion, we have analyzed the comics not with the intention of making this language more and more present in the classes but with the attempt of understanding them as a tool that may contribute a lot for a real criticism and for the explicitness of the historic moment in which they were created, for a teaching, at the same time, more playful and critic. In methodological terms, we have selected three Mafalda’s strips (named “The naturalization of the differences”, “The inhumanization” and “The competition”, shown on Toda Mafalda (2002 aiming to replace the insights herein sketched. This work is a part of the master’s degree lecture, read  at the Postgraduation Program in Education of UERJ (ProPed in March 2011, under the title of Mafalda in The History class: a criticism of the bourgeoise society charactheristic elements and the collective making-up of hegemonic meanings.

  2. Comparison of the inhibitory capacity of two groups of pure natural extract on the crystallization of two types of material compound urinary stones in vitro study

    Science.gov (United States)

    Beghalia, Mohamed; Ghalem, Said; Allali, Hocine

    2015-10-01

    Urolithiasis is defined as the result of an abnormal precipitation within the urinary tract. This precipitation is most often from the normal constituents of the urine. This is a fairly common condition in the population. She is happy and recurrent etiology is often unknown if hypothetical. In Algeria, as in many countries, a large number of patients use herbal medicines in the treatment of their diseases including urolithiasis. Thus the aim of this study is the most widely used to evaluate the effectiveness of aqueous extracts of medicinal plants, in the treatment of calcium urolithiasis oxalo-and magnesium-amoniaco in vitro. The study also examines the effect of these extracts on the states of crystallization (nucleation, crystal growth, crystal aggregation), followed by photography on polarized light microscope.In this regard, we are devoted to studying the crystallization steps from oxalo-calcium and phospho-calcic prepared as artificial urine and supersaturated aqueous solutions, maintained at 37 °C to remain close to biological conditions. Extracts of the first group of herbs: Ammodaucus leucotrichus, Ajuga iva, Globularia alypum, Atriplex halimus are studied on the crystallization calcium oxalate, we cite the Ammodaucus leucotrichus which acts on the stages of nucleation, growth and the aggregation with a total inhibition. The second group of extracts plants tested on calcium phosphate crystallization : Acacia raddiana, Citrullus colocynthis, Rhus tripartita, Pistacia lentiscu, Warionia saharae, are able to significantly reduce phosphate crystallization in vitro. It is easily proved by FTIR and optical microscope. In conclusion the results of our work allows us to confirm the use of these plants as an aqueous decoction, in the field of urolithiasis. These activities may help to strengthen the body in depressed situations.

  3. Nature vs. nurture in the low-density environment: structure and evolution of early-type dwarf galaxies in poor groups

    Science.gov (United States)

    Annibali, F.; Grützbauch, R.; Rampazzo, R.; Bressan, A.; Zeilinger, W. W.

    2011-04-01

    We present the stellar population properties of 13 dwarf galaxies residing in poor groups (low-density environment, LDE) observed with VIMOS at VLT. Ages, metallicities, and [α/Fe] ratios were derived within an r < re/2 aperture from the Lick indices Hβ, Mgb, Fe5270, and Fe5335 through comparison with our simple stellar population (SSP) models that account for variable [α/Fe] ratios. For a fiducial subsample of 10 early-type dwarfs, we derived median values and scatters around the medians of 5.7 ± 4.4 Gyr, -0.26 ± 0.28, and -0.04 ± 0.33 for age, log Z/Z⊙, and [α/Fe] , respectively. For a selection of bright early-type galaxies (ETGs) from an earlier sample residing in a comparable environment, we derive median values of 9.8 ± 4.1 Gyr, 0.06 ± 0.16, and 0.18 ± 0.13 for the same stellar population parameters. It follows that dwarfs are on average younger, less metal rich, and less enhanced in the α-elements than giants, in agreement with the extrapolation to the low-mass regime of the scaling relations derived for giant ETGs. From the total (dwarf + giant) sample, we find that age ∝ σ0.39 ± 0.22, Z ∝ σ0.80 ± 0.16, and α/Fe ∝ σ0.42 ± 0.22. We also find correlations with morphology, in the sense that the metallicity and the [α/Fe] ratio increase with the Sersic index n or with the bulge-to-total light fraction B/T. The presence of a strong morphology-[α/Fe] relation appears to contradict the possible evolution along the Hubble sequence from low B/T (low n) to high B/T (high n) galaxies. We also investigate the role played by environment by comparing the properties of our LDE dwarfs with those of Coma red passive dwarfs from the literature. We find possible evidence that LDE dwarfs experienced more prolonged star formations than Coma dwarfs, however larger data samples are needed to draw firmer conclusions. Based on observations obtained at the European Southern Observatory, La Silla, Chile.

  4. Effects of grazing, phosphorus and light on the growth rates of major bacterioplankton taxa in the coastal NW Mediterranean

    Czech Academy of Sciences Publication Activity Database

    Sánchez, O.; Koblížek, Michal; Gasol, J.M.; Ferrera, I.

    2017-01-01

    Roč. 9, č. 3 (2017), s. 300-309 ISSN 1758-2229 R&D Projects: GA ČR GA13-11281S; GA MŠk(CZ) LO1416 Institutional support: RVO:61388971 Keywords : AEROBIC ANOXYGENIC PHOTOTROPHS * CATALYZED REPORTER DEPOSITION * NATURAL PLANKTONIC BACTERIA Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.363, year: 2016

  5. Environmental Sensitivity in Nuclear Emergencies in Rural and Semi-natural Environments. Report of Working Group 8, Environmental Sensitivity of EMRAS II Topical Heading Approaches for Assessing Emergency Situations. Environmental Modelling for RAdiation Safety (EMRAS II) Programme

    International Nuclear Information System (INIS)

    2013-11-01

    Environmental assessment models are used for evaluating the radiological impact of actual and potential releases of radionuclides to the environment. They are essential tools for use in the regulatory control of routine discharges to the environment and also in planning measures to be taken in the event of accidental releases. They are also used for predicting the impact of releases which may occur far into the future, for example, from underground radioactive waste repositories. It is important to verify, to the extent possible, the reliability of the predictions of such models by comparison with measured values in the environment or by comparing them with the predictions of other models. The IAEA has been organizing programmes of international model testing since the 1980s. The programmes have contributed to a general improvement in models, in transfer data and in the capabilities of modellers in Member States. IAEA publications on this subject over the past three decades demonstrate the comprehensive nature of the programmes and record the associated advances which have been made. From 2009 to 2011, the IAEA organized a programme entitled Environmental Modelling for RAdiation Safety (EMRAS II), which concentrated on the improvement of environmental transfer models and the development of reference approaches to estimate the radiological impacts on humans, as well as on flora and fauna, arising from radionuclides in the environment. The following topics were addressed in nine working groups: Reference Approaches for Human Dose Assessment - Working Group 1: Reference Methodologies for Controlling Discharges of Routine Releases; - Working Group 2: Reference Approaches to Modelling for Management and Remediation at NORM and Legacy Sites; - Working Group 3: Reference Models for Waste Disposal Reference Approaches for Biota Dose Assessment; - Working Group 4: Biota Modelling; - Working Group 5: Wildlife Transfer Coefficient Handbook; - Working Group 6: Biota Dose

  6. Direct and indirect effects of vertical mixing, nutrients and ultraviolet radiation on the bacterioplankton metabolism in high-mountain lakes from southern Europe

    Science.gov (United States)

    Durán, C.; Medina-Sánchez, J. M.; Herrera, G.; Villar-Argaiz, M.; Villafañe, V. E.; Helbling, E. W.; Carrillo, P.

    2014-05-01

    led to higher HBP. Consequently, EOC satisfied BCD in the clear lakes, particularly in the clearest one [LC]. Our results suggest that the higher vulnerability of bacteria to the damaging effects of UVR may be particularly accentuated in the opaque lakes and further recognizes the relevance of light exposure history and biotic interactions on bacterioplankton metabolism when coping with fluctuating radiation and nutrient inputs.

  7. Effect of natural gas flaring upon the butterfly, Eurema hecabe (Lepidoptera: Pieridae) and its host plant, Cassia tora (Fabales: Fabaceae) in two group gathering stations of Assam, India: an approach of environmental monitoring.

    Science.gov (United States)

    Sarma, Bitopan; Bhattacharyya, Pranab Ram; Bhuyan, Mantu

    2018-03-07

    Apart from other pollutants, flaring of natural gas adds carbon dioxide into the environment and changes the atmospheric composition, including temperature and humidity. As a major gaseous product, carbon dioxide changes plant structural components as well as herbivores, i.e., insect by dilution of nitrogen under such circumstances. Present analysis demonstrated the impact of gas flaring upon adjoining biota especially Eurema hecabe butterfly and its host plant, Cassia tora in some wells (group gathering stations) of Assam, India. Analysis, pertaining from the current investigation, documented higher carbon dioxide as well as temperature in the studied flaring sites. Apart from this, reduction of leaf nitrogen, SLA, and chlorophyll with increasing in LDMC, thickness, and carbon in the studied plant as well as poor developmental rate, RGR, ECD with high RCR in insect indicated severe impact of flaring in those areas. Simulation studies with different concentration of CO 2 in open top chamber on the plant and butterfly also revealed similar trend of results.

  8. A natural variant of the cysteine protease virulence factor of group A Streptococcus with an arginine-glycine-aspartic acid (RGD) motif preferentially binds human integrins alphavbeta3 and alphaIIbbeta3.

    Science.gov (United States)

    Stockbauer, K E; Magoun, L; Liu, M; Burns, E H; Gubba, S; Renish, S; Pan, X; Bodary, S C; Baker, E; Coburn, J; Leong, J M; Musser, J M

    1999-01-05

    The human pathogenic bacterium group A Streptococcus produces an extracellular cysteine protease [streptococcal pyrogenic exotoxin B (SpeB)] that is a critical virulence factor for invasive disease episodes. Sequence analysis of the speB gene from 200 group A Streptococcus isolates collected worldwide identified three main mature SpeB (mSpeB) variants. One of these variants (mSpeB2) contains an Arg-Gly-Asp (RGD) sequence, a tripeptide motif that is commonly recognized by integrin receptors. mSpeB2 is made by all isolates of the unusually virulent serotype M1 and several other geographically widespread clones that frequently cause invasive infections. Only the mSpeB2 variant bound to transfected cells expressing integrin alphavbeta3 (also known as the vitronectin receptor) or alphaIIbbeta3 (platelet glycoprotein IIb-IIIa), and binding was blocked by a mAb that recognizes the streptococcal protease RGD motif region. In addition, mSpeB2 bound purified platelet integrin alphaIIbbeta3. Defined beta3 mutants that are altered for fibrinogen binding were defective for SpeB binding. Synthetic peptides with the mSpeB2 RGD motif, but not the RSD sequence present in other mSpeB variants, blocked binding of mSpeB2 to transfected cells expressing alphavbeta3 and caused detachment of cultured human umbilical vein endothelial cells. The results (i) identify a Gram-positive virulence factor that directly binds integrins, (ii) identify naturally occurring variants of a documented Gram-positive virulence factor with biomedically relevant differences in their interactions with host cells, and (iii) add to the theme that subtle natural variation in microbial virulence factor structure alters the character of host-pathogen interactions.

  9. Distribution and production of plankton communities in the subtropical convergence zone of the Sargasso Sea. I. Phytoplankton and bacterioplankton

    DEFF Research Database (Denmark)

    Riemann, Lasse; Nielsen, Torkel Gissel; Kragh, Theis

    2011-01-01

    . With the aim of improving the understanding of physical and lower trophic level processes in the area, we carried out field studies of physical, chemical and biological characteristics along 3 transects crossing thermal fronts associated with the STCZ in March to April 2007. Thermal and chemical stratification....... Bacterial biomass was roughly equal to half of the phytoplankton biomass. We did not find elevated levels of primary production or biomass of specific phytoplankton groups associated with the STCZ, probably due to a pronounced variability between stations along transects. Nevertheless, distinct increases...

  10. Latitudinal Trends in Abundant and Rare Bacterioplankton Community Structure and Diversity in Surface Waters of the Pacific Ocean

    Science.gov (United States)

    Jeffrey, W. H.; Moss, J. A.; Snyder, R.; Pakulski, J. D.

    2016-02-01

    To fully comprehend planktonic diversity and the roles of microorganisms in global biogeochemical cycling, we must recognize the distribution patterns of planktonic taxa and phylotypes and their controlling environmental factors. To advance this understanding, Illumina sequencing targeting the 16S rRNA gene was used to evaluate latitudinal patterns of bacterial taxa as well as diversity in surface waters in the Pacific Ocean. Surface water was collected at 37 stations at 370 km intervals in a 16,200 km transect from 71 N to 68 S in the Pacific Ocean from August to November 2003. These samples were collected on Sterivex filters and kept continuously at -80 C until recent processing which produced over 200k reads per site, half of which were discernible down to the genus level. Bray-Curtis analysis of known genera produced 4 major clusters—sub-Arctic/Arctic, tropical, temperate, and sub-Antarctic/Antarctic. Analysis of only the rare (< 1%) genera produced the same 4 major clusters, although the clusters were most congruent in their geographic distribution when only the abundant taxa were included. Key phyla responsible for these groupings include genera of the Proteobacteria and Cyanobacteria, and as expected, include the pronounced presence of Prochlorococcus in the temperate and equatorial regions. However, many robust trends such as unipolar and bipolar distribution in both the abundant (≥1%) and rare (< 1%) genera within phyla Verrucomicrobia, Actinobacteria, and Barteriodetes, were also apparent. The data sheds light on distribution patterns of the Oleibacter, Thalassobius, Olleya, Salegentibacter, Ulvibacter, Bizionia, Pirellula, and many other additional, understudied genera. Of the 655 identified genera, no significant gradients in gamma diversity were apparent when 12 commonly used species and phylogenetic indices were applied.

  11. Group X

    Energy Technology Data Exchange (ETDEWEB)

    Fields, Susannah

    2007-08-16

    This project is currently under contract for research through the Department of Homeland Security until 2011. The group I was responsible for studying has to remain confidential so as not to affect the current project. All dates, reference links and authors, and other distinguishing characteristics of the original group have been removed from this report. All references to the name of this group or the individual splinter groups has been changed to 'Group X'. I have been collecting texts from a variety of sources intended for the use of recruiting and radicalizing members for Group X splinter groups for the purpose of researching the motivation and intent of leaders of those groups and their influence over the likelihood of group radicalization. This work included visiting many Group X websites to find information on splinter group leaders and finding their statements to new and old members. This proved difficult because the splinter groups of Group X are united in beliefs, but differ in public opinion. They are eager to tear each other down, prove their superiority, and yet remain anonymous. After a few weeks of intense searching, a list of eight recruiting texts and eight radicalizing texts from a variety of Group X leaders were compiled.

  12. Group Flow and Group Genius

    Science.gov (United States)

    Sawyer, Keith

    2015-01-01

    Keith Sawyer views the spontaneous collaboration of group creativity and improvisation actions as "group flow," which organizations can use to function at optimum levels. Sawyer establishes ideal conditions for group flow: group goals, close listening, complete concentration, being in control, blending egos, equal participation, knowing…

  13. Isopermutation group

    Energy Technology Data Exchange (ETDEWEB)

    Muktibodh, A. S. [Department of Mathematics, Mohota College of Science, NAGPUR-440009 India E-mail: amukti2000@yahoo.com (India)

    2015-03-10

    The concept of ‘Isotopy’ as formulated by Ruggero Maria Santilli [1, 2, 3] plays a vital role in the development of Iso mathematics. Santilli defined iso-fields of characteristic zero. In this paper we extend this definition to define Iso-Galois fields [4] which are essentially of non-zero characteristic. Isotopically isomorphic realizations of a group define isopermutation group which gives a clear cut distinction between automorphic groups and isotopic groups.

  14. Chemistry of Natural Dyes

    Indian Academy of Sciences (India)

    The sulfonated oils, which possess better metal bind- ing capacity than the natural oils due to the presence of sulfonic acid group, bind to metal ions forming a complex with the dye to give superior fastness and hue. Limitations of Natural Dyes. Tedious extraction of colouring component from the raw mate- rial, low colour ...

  15. Permutation groups

    CERN Document Server

    Passman, Donald S

    2012-01-01

    This volume by a prominent authority on permutation groups consists of lecture notes that provide a self-contained account of distinct classification theorems. A ready source of frequently quoted but usually inaccessible theorems, it is ideally suited for professional group theorists as well as students with a solid background in modern algebra.The three-part treatment begins with an introductory chapter and advances to an economical development of the tools of basic group theory, including group extensions, transfer theorems, and group representations and characters. The final chapter feature

  16. PLURALIZING NATURE

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    not necessary mean planning for a one common nature. As exemplified by the River Aire Re-naturalization Project (2002-2015), landscape architecture might provide an alternative approach to nature restoration that is more site specific and allows for multiple interpretations to coexist. In the presentation...

  17. Environmental groups in politics

    International Nuclear Information System (INIS)

    Lowe, P.; Goyder, J.

    1983-01-01

    The subject is covered in chapters, entitled: introduction; (Part I) the environmental movement (environmental groups and the attentive public; the episodic development of the environmental movement; the underlying values of environmentalism; the roots of environmental concern; the social limits to growth; elite manipulation of values); the organisation of environmental groups; environmental groups in national politics; environmental groups in local politics; (Part II) the Henley Society; Friends of the Earth; the National Trust; the Royal Society for Nature Conservation; the European Environmental Bureau. (U.K.)

  18. The City and Nature

    Directory of Open Access Journals (Sweden)

    Eduard Tovmasyan

    2016-09-01

    Full Text Available Animate “nature–1” around us is transforming into supported or non-supported by man “nature-2” within the framework of the urban development of town areas. Interaction of town and nature is a bilateral process. Experts underline 4 groups of town planning risks related to the interaction of town and nature: ecological, natural and biosphere, sanitary-epidemiologic risks as well as planning and management risks. The latter is often connected with protest population activities. The magazine is looking forward to readers comments.

  19. Reflection groups

    International Nuclear Information System (INIS)

    Eggermont, G.

    2006-01-01

    In 2005, PISA organised proactive meetings of reflection groups on involvement in decision making, expert culture and ethical aspects of radiation protection.All reflection group meetings address particular targeted audiences while the output publication in book form is put forward

  20. Group Theatre.

    Science.gov (United States)

    Clark, Brian

    The group interpretation approach to theatre production is defined as a method that will lead to production of plays that will appeal to "all the layers of the conscious and unconscious mind." In practice, it means that the group will develop and use resources of the theatre that orthodox companies too often ignore. The first two chapters of this…

  1. PLURALIZING NATURE

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    Denmark is widely recognised for its democratic approach to planning and the idea of planning for the common good. This interest in the common good and common values seems also to be reflected in the way which nature restoration is planned and managed – one common nature directed by the public...... authorities. But nature restoration is far from being a neural undertaking. Just like any other type of heritage production it can be the source of dissonance – ‘our’ nature is not necessary ‘their’ nature. Often this dissonance is managed in ways, which are not particular sensitive to site......-specificity. As exemplified by the Skjern River Restoration Project (1999-2003), one interpretation of the landscape sometimes suppresses other valid interpretations neglecting its diverse history. However, evidence from Switzerland suggests that planning for the common good, in the case of nature restoration, does...

  2. Dynamical Groups

    Science.gov (United States)

    Paldus, Josef

    The well known symmetry (invariance, degeneracy) dynamical groups or algebras of quantum mechanical Hamiltonians provide quantum numbers (conservation laws, integrals of motion) for state labeling and the associated selection rules. In addition, it is often advantageous to employ much larger groups, referred to as the dynamical groups (noninvariance groups, dynamical algebras, spectrum generating algebras), which may or may not be the invariance groups of the studied system [4.1,2,3,4,5,6,7]. In all known cases, they are Lie groups (LGs), or rather corresponding Lie algebras (LAs), and one usually requires that all states of interest of a system be contained in a single irreducible representation (irrep). Likewise, one may require that the Hamiltonian be expressible in terms of the Casimir operators of the corresponding universal enveloping algebra [4.8,9]. In a weaker sense, one regards any group (or corresponding algebra) as a dynamical group if the Hamiltonian can be expressed in terms of its generators [4.10,11,12]. In nuclear physics, one sometimes distinguishes exact (baryon number preserving), almost exact (e.g., total isospin), approximate (e.g., SU(3) of the "eightfold way") and model (e.g., nuclear shell model) dynamical symmetries [4.13]. The dynamical groups of interest in atomic and molecular physics can be conveniently classified by their topological characteristic of compactness. Noncompact LGs (LAs) generally arise in simple problems involving an infinite number of bound states, while those involving a finite number of bound states (e.g., molecular vibrations or ab initio models of electronic structure) exploit compact LG's.

  3. Temporal naturalism

    Science.gov (United States)

    Smolin, Lee

    2015-11-01

    Two people may claim both to be naturalists, but have divergent conceptions of basic elements of the natural world which lead them to mean different things when they talk about laws of nature, or states, or the role of mathematics in physics. These disagreements do not much affect the ordinary practice of science which is about small subsystems of the universe, described or explained against a background, idealized to be fixed. But these issues become crucial when we consider including the whole universe within our system, for then there is no fixed background to reference observables to. I argue here that the key issue responsible for divergent versions of naturalism and divergent approaches to cosmology is the conception of time. One version, which I call temporal naturalism, holds that time, in the sense of the succession of present moments, is real, and that laws of nature evolve in that time. This is contrasted with timeless naturalism, which holds that laws are immutable and the present moment and its passage are illusions. I argue that temporal naturalism is empirically more adequate than the alternatives, because it offers testable explanations for puzzles its rivals cannot address, and is likely a better basis for solving major puzzles that presently face cosmology and physics. This essay also addresses the problem of qualia and experience within naturalism and argues that only temporal naturalism can make a place for qualia as intrinsic qualities of matter.

  4. Natural Philosophy

    OpenAIRE

    Blair, Ann M.

    2006-01-01

    Natural philosophy” is often used by European historians as an umbrella term to designate the study of nature before it can easily be identified with what we call “science” today, to avoid the modern and potentially anachronistic connotations of that term. But “natural philosophy” (and its equivalents in different languages) was also an actor's category, a term commonly used throughout the early modern period and typically defined quite broadly as the study of natural bodies. As the central ...

  5. Computer group

    International Nuclear Information System (INIS)

    Bauer, H.; Black, I.; Heusler, A.; Hoeptner, G.; Krafft, F.; Lang, R.; Moellenkamp, R.; Mueller, W.; Mueller, W.F.; Schati, C.; Schmidt, A.; Schwind, D.; Weber, G.

    1983-01-01

    The computer groups has been reorganized to take charge for the general purpose computers DEC10 and VAX and the computer network (Dataswitch, DECnet, IBM - connections to GSI and IPP, preparation for Datex-P). (orig.)

  6. Group technology

    International Nuclear Information System (INIS)

    Rome, C.P.

    1976-01-01

    Group Technology has been conceptually applied to the manufacture of batch-lots of 554 machined electromechanical parts which now require 79 different types of metal-removal tools. The products have been grouped into 7 distinct families which require from 8 to 22 machines in each machine-cell. Throughput time can be significantly reduced and savings can be realized from tooling, direct-labor, and indirect-labor costs

  7. Lie groups and algebraic groups

    Indian Academy of Sciences (India)

    . These fields are interrelated and each of these fields contributes to the other. 2. Examples and classification. We first give some examples of Lie groups. The most frequently occurring ones are the linear classical groups GLn(R), GLn(C), ...

  8. Lie groups and algebraic groups

    Indian Academy of Sciences (India)

    M S RAGHUNATHAN and T N VENKATARAMANA. ∗. School of Mathematics, Tata Institute of Fundamental ... linear classical groups GLn(R), GLn(C), SOn(R),. SOn(C), Spn(R) and Spn(C). Let us call a con- nected Lie ..... split groups due respectively to C C Moore and. V Deodhar. B Sury solved the congruence subgroup ...

  9. Abelian groups

    CERN Document Server

    Fuchs, László

    2015-01-01

    Written by one of the subject’s foremost experts, this book focuses on the central developments and modern methods of the advanced theory of abelian groups, while remaining accessible, as an introduction and reference, to the non-specialist. It provides a coherent source for results scattered throughout the research literature with lots of new proofs. The presentation highlights major trends that have radically changed the modern character of the subject, in particular, the use of homological methods in the structure theory of various classes of abelian groups, and the use of advanced set-theoretical methods in the study of undecidability problems. The treatment of the latter trend includes Shelah’s seminal work on the undecidability in ZFC of Whitehead’s Problem; while the treatment of the former trend includes an extensive (but non-exhaustive) study of p-groups, torsion-free groups, mixed groups, and important classes of groups arising from ring theory. To prepare the reader to tackle these topics, th...

  10. Framing nature

    NARCIS (Netherlands)

    Jansen, Peter

    2017-01-01

    This PhD thesis is about communication concerning nature in the Netherlands. The purpose of this exploratory study is to take both a theoretical and an empirical look at whether (implicit) religious elements play a role in this communication about nature in the Netherlands.

    In this PhD

  11. natural theology

    African Journals Online (AJOL)

    p1243322

    ancient Greece. The aim of this article is not to propose a new natural theology; nor does it seek to resurrect older models. It is necessary, however, to examine the extent to ... In studies like this one the South African context is relevant, as Barth is ... human reason to reach knowledge about God's nature and works insofar as.

  12. Nature Watch

    Indian Academy of Sciences (India)

    Nature Watch. When Dragons Fly ... K A Subramanian. A Natural History of Odonata. We have all held them by their wings, made them lift pebbles from our palms, tied their tails to paper flags and watched them flyaway, wondering all the while where and how they lived and what they did. I only knew that we called them ...

  13. Nature Detectives

    Science.gov (United States)

    Harr, Natalie; Lee, Richard E.; Jr.

    2010-01-01

    Richard Louv's "Last Child in the Woods" (2008) added to a growing consensus to get children outside and experiencing nature. Using ideas from place-based education, the authors present a simple year-long project that brings science, nature, and other curriculum standards to life right in your school yard. With a focus on journaling, this project…

  14. Matematica Natural.

    Science.gov (United States)

    Lozano, Patricia; Medearis, Linda

    Matematica Natural (Natural Mathematics) is a mathematics curriculum for young children based on the assumption that they learn mathematics through concrete, real life, relevant experiences and that educational differences rather than cultural differences influence math achievement. The curriculum uses hands-on materials and activities to teach…

  15. Natur formet

    DEFF Research Database (Denmark)

    Søberg, Martin

    2011-01-01

    Anmeldelse af Malene Hauxner, "Fra naturlig natur til SUPERNATUR – Europæisk landskabsarkitektur 1967-2007 set fra Danmark", Risskov: Ikaros Press, 2011.......Anmeldelse af Malene Hauxner, "Fra naturlig natur til SUPERNATUR – Europæisk landskabsarkitektur 1967-2007 set fra Danmark", Risskov: Ikaros Press, 2011....

  16. Framing nature

    NARCIS (Netherlands)

    Jansen, Peter

    2017-01-01

    This PhD thesis is about communication concerning nature in the Netherlands. The purpose of this exploratory study is to take both a theoretical and an empirical look at whether (implicit) religious elements play a role in this communication about nature in the Netherlands.   In this PhD thesis

  17. Doing focus group research

    DEFF Research Database (Denmark)

    Lindegaard, Laura Bang

    2014-01-01

    Scholars of ethnomethodologically informed discourse studies are often sceptical of the use of interview data such as focus group data. Some scholars quite simply reject interview data with reference to a general preference for so-called naturally occurring data. Other scholars acknowledge......, not as something that pre-exists or goes beyond the situated interaction. This article, however, challenges not only the first, but also the second position and suggests that it is, after all, possible to do committedly ethnomethodological studies of focus group data that demonstrate how members of a focus group...

  18. Dissonant Nature

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2013-01-01

    Nature restoration is far from being a neural undertaking. Just like any other type of heritage production it can be the source of dissonance – ‘our’ nature is not necessary ‘their’ nature. Often this dissonance is managed in ways, which are not particular sensitive to site......-specificity. As exemplified by the Skjern River Restoration Project (1999-2003), one interpretation of the landscape sometimes suppresses other valid interpretations neglecting its diverse history. Landscape architecture might, however, provide an alternative approach to nature restoration that is more site specific...... and allows for multiple interpretations to coexist. Evidence can be found in the Re-naturalization of River Aire (2002-2015), a restoration project, which reveals approaches that could be labelled landscape architecture specific....

  19. Mining microbial metatranscriptomes for expression of antibiotic resistance genes under natural conditions

    Science.gov (United States)

    Versluis, Dennis; D'Andrea, Marco Maria; Ramiro Garcia, Javier; Leimena, Milkha M.; Hugenholtz, Floor; Zhang, Jing; Öztürk, Başak; Nylund, Lotta; Sipkema, Detmer; Schaik, Willem Van; de Vos, Willem M.; Kleerebezem, Michiel; Smidt, Hauke; Passel, Mark W. J. Van

    2015-07-01

    Antibiotic resistance genes are found in a broad range of ecological niches associated with complex microbiota. Here we investigated if resistance genes are not only present, but also transcribed under natural conditions. Furthermore, we examined the potential for antibiotic production by assessing the expression of associated secondary metabolite biosynthesis gene clusters. Metatranscriptome datasets from intestinal microbiota of four human adults, one human infant, 15 mice and six pigs, of which only the latter have received antibiotics prior to the study, as well as from sea bacterioplankton, a marine sponge, forest soil and sub-seafloor sediment, were investigated. We found that resistance genes are expressed in all studied ecological niches, albeit with niche-specific differences in relative expression levels and diversity of transcripts. For example, in mice and human infant microbiota predominantly tetracycline resistance genes were expressed while in human adult microbiota the spectrum of expressed genes was more diverse, and also included β-lactam, aminoglycoside and macrolide resistance genes. Resistance gene expression could result from the presence of natural antibiotics in the environment, although we could not link it to expression of corresponding secondary metabolites biosynthesis clusters. Alternatively, resistance gene expression could be constitutive, or these genes serve alternative roles besides antibiotic resistance.

  20. Group learning

    DEFF Research Database (Denmark)

    Pimentel, Ricardo; Noguira, Eloy Eros da Silva; Elkjær, Bente

    The article presents a study that aims at the apprehension of the group learning in a top management team composed by teachers in a Brazilian Waldorf school whose management is collective. After deciding to extend the school, they had problems recruiting teachers who were already trained based...... with which they coexist. To achieve this, the research adopted phenomenology as a method and ethnography as strategy, using participant observation, in-depth interviews, and interviews-to-the-double. The results show that the collective management practice is a crossroad of other practices......, and they are interrelated to the group learning as the construction, maintenance and reconstruction of the intelligibility of practices. From this perspective, it can be said that learning is a practice and not an exceptional phenomenon. Building, maintaining and rebuilding the intelligibility is the group learning...

  1. Writing Nature

    Directory of Open Access Journals (Sweden)

    Kristin Asdal

    2014-06-01

    Full Text Available This special issue of the Nordic Journal of Science and Technology Studies is interested in how nature, in different versions and forms, is invited into our studies, analyses, and stories. How is it that we “write nature”? How is it that we provide space for, and actually describe the actors, agents, or surroundings, in our stories and analyses? The articles in the issue each deal with different understandings of both the practices of writing and the introduction of various natures into these. In this introduction to the issue the editors engage with actor-network theory as a material semiotic resource for writing nature. We propose to foreground actor-network theory as a writing tool, at the expense of actor-network theory as a distinct vocabulary. In doing this and pointing out the semiotic origins to material-semiotics we also want to problematize a clear-cut material approach to writing nature.

  2. Natural Childbirth

    Science.gov (United States)

    ... Things That Help Feelings Expert Answers Q&A Movies & More for Teens Teens site Sitio para adolescentes ... the Pain? Print en español Parto natural Some women choose to give birth using no medications at ...

  3. Natural Communities

    Data.gov (United States)

    Kansas Data Access and Support Center — This dataset shows the locations of known tracts of high quality natural communities in Kansas, generalized to the PLSS section. It is not a compehensive dataset of...

  4. Natural Propositions

    DEFF Research Database (Denmark)

    Stjernfelt, Frederik

    Preface -- Introduction -- The generality of signs -- Dicisigns -- Some consequences of the dicisign doctrine -- Dicisigns and cognition -- Natural propositions--the evolution of semiotic self-control -- Dicisigns beyond language -- Operational and optimal iconicity in Peirce's diagrammatology...

  5. Statistical Group Comparison

    CERN Document Server

    Liao, Tim Futing

    2011-01-01

    An incomparably useful examination of statistical methods for comparisonThe nature of doing science, be it natural or social, inevitably calls for comparison. Statistical methods are at the heart of such comparison, for they not only help us gain understanding of the world around us but often define how our research is to be carried out. The need to compare between groups is best exemplified by experiments, which have clearly defined statistical methods. However, true experiments are not always possible. What complicates the matter more is a great deal of diversity in factors that are not inde

  6. Natural aphrodisiacs.

    Science.gov (United States)

    Shamloul, Rany

    2010-01-01

    The search for a remedy or a prescription that can enhance sexual function and/or treat male erectile dysfunction has been an obsession throughout known history. Whether it was an Eastern civilization or a Western one, religious or atheist, man's aspiration for a better or best "manhood" has been a history-time goal. This review will discuss the current research done on the most popular natural aphrodisiacs and examine the weight of evidence to support or discourage the use of any of these substances to enhance sexual desire and/or function. Review of the current evidence on the use of natural substances as aphrodisiacs. Efficacy of natural aphrodisiacs in enhancing sexual function in men and women. There is little evidence from literature to recommend the usage of natural aphrodisiacs for the enhancement of sexual desire and/or performance. Data on yohimbine's efficacy does not support the wide use of the drug, which has only mild effects in the treatment of psychogenic ED. Although there's a positive trend towards recommending ginseng as an effective aphrodisiac, however, more in depth studies involving large number of subjects and its mechanism of action are needed before definite conclusions could be reached. Data on the use of natural aphrodisiacs in women is limited. The current body of objective evidence does not support the use of any natural aphrodisiac as an effective treatment for male or female sexual dysfunctions. Potent men and men with ED will continue the search for natural aphrodisiacs despite the current disappointing data on their effectiveness. Care should be taken regarding the fraud addition of sildenafil analogues to natural aphrodisiacs.

  7. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2011-01-01

    The CMS Communications Group, established at the start of 2010, has been busy in all three areas of its responsibility: (1) Communications Infrastructure, (2) Information Systems, and (3) Outreach and Education. Communications Infrastructure There are now 55 CMS Centres worldwide that are well used by physicists working on remote CMS shifts, Computing operations, data quality monitoring, data analysis and outreach. The CMS Centre@CERN in Meyrin, is the centre of the CMS offline and computing operations, hosting dedicated analysis efforts such as during the CMS Heavy Ion lead-lead running. With a majority of CMS sub-detectors now operating in a “shifterless” mode, many monitoring operations are now routinely performed from there, rather than in the main Control Room at P5. The CMS Communications Group, CERN IT and the EVO team are providing excellent videoconferencing support for the rapidly-increasing number of CMS meetings. In parallel, CERN IT and ...

  8. Embeddings of graph braid and surface groups in right-angled Artin groups and braid groups

    OpenAIRE

    Crisp, John; Wiest, Bert

    2003-01-01

    We prove by explicit construction that graph braid groups and most surface groups can be embedded in a natural way in right-angled Artin groups, and we point out some consequences of these embedding results. We also show that every right-angled Artin group can be embedded in a pure surface braid group. On the other hand, by generalising to right-angled Artin groups a result of Lyndon for free groups, we show that the Euler characteristic -1 surface group (given by the relation x^2y^2=z^2) nev...

  9. Examining the Impact of DIfferent Virtual Manipulative Types on the Nature of Students' SMall-Group Discussions: An Exploratory Mixed-Methods Case Study of Techno-Mathematical Discourse

    OpenAIRE

    Anderson-Pence, Katie L.

    2014-01-01

    This study examined the influence of different virtual manipulative types on the nature of students’ techno-mathematical discourse (TMD) when working with a partner. The research used a concurrent mixed-methods design using identical samples to compare and synthesize the results. For this study, six fifth-grade students participated in nine sessions of mathematics instruction using virtual manipulatives. The study compared three virtual manipulative types: combined (multiple representations, ...

  10. Natural Disaster and Natural Selection

    OpenAIRE

    Uchida, Hirofumi; Miyakawa, Daisuke; Hosono, Kaoru; Ono, Arito; Uchino, Taisuke; Uesugi, Iichiro

    2013-01-01

    In this paper, we investigate whether a natural selection mechanism works for firm exit. By using data of firms after a devastating earthquake, the Greeat Tohoku Earthquake, we examine the impact of firm efficiency on firm exit both inside and outside the earthquake-affected areas. We find evidence suggesting that more efficeint firms are less likely to exit both inside and outside the affected areas, which supports the natural selection mechanism. However, we also find that the mechanism is ...

  11. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2011-01-01

    The CMS Communications Group has been busy in all three areas of its responsibility: (1) Communications Infrastructure, (2) Information Systems, and (3) Outreach and Education. Communications Infrastructure The 55 CMS Centres worldwide are well used by physicists working on remote CMS shifts, Computing operations, data quality monitoring, data analysis and outreach. The CMS Centre@CERN in Meyrin, is the centre of the CMS Offline and Computing operations, and a number of subdetector shifts can now take place there, rather than in the main Control Room at P5. A new CMS meeting room has been equipped for videoconferencing in building 42, next to building 40. Our building 28 meeting room and the facilities at P5 will be refurbished soon and plans are underway to steadily upgrade the ageing equipment in all 15 CMS meeting rooms at CERN. The CMS evaluation of the Vidyo tool indicates that it is not yet ready to be considered as a potential replacement for EVO. The Communications Group provides the CMS-TV (web) cha...

  12. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2010-01-01

    The CMS Communications Group, established at the start of 2010, has been strengthening the activities in all three areas of its responsibility: (1) Communications Infrastructure, (2) Information Systems, and (3) Outreach and Education. Communications Infrastructure The Communications Group has invested a lot of effort to support the operations needs of CMS. Hence, the CMS Centres where physicists work on remote CMS shifts, Data Quality Monitoring, and Data Analysis are running very smoothly. There are now 55 CMS Centres worldwide, up from just 16 at the start of CMS data-taking. The latest to join are Imperial College London, the University of Iowa, and the Università di Napoli. The CMS Centre@CERN in Meyrin, which is now full repaired after the major flooding at the beginning of the year, has been at the centre of CMS offline and computing operations, most recently hosting a large fraction of the CMS Heavy Ion community during the lead-lead run. A number of sub-detector shifts can now take pla...

  13. Group play

    DEFF Research Database (Denmark)

    Tychsen, Anders; Hitchens, Michael; Brolund, Thea

    2008-01-01

    Role-playing games (RPGs) are a well-known game form, existing in a number of formats, including tabletop, live action, and various digital forms. Despite their popularity, empirical studies of these games are relatively rare. In particular there have been few examinations of the effects of the v......Role-playing games (RPGs) are a well-known game form, existing in a number of formats, including tabletop, live action, and various digital forms. Despite their popularity, empirical studies of these games are relatively rare. In particular there have been few examinations of the effects...... of the various formats used by RPGs on the gaming experience. This article presents the results of an empirical study, examining how multi-player tabletop RPGs are affected as they are ported to the digital medium. Issues examined include the use of disposition assessments to predict play experience, the effect...... of group dynamics, the influence of the fictional game characters and the comparative play experience between the two formats. The results indicate that group dynamics and the relationship between the players and their digital characters, are integral to the quality of the gaming experience in multiplayer...

  14. Emancipating Nature

    DEFF Research Database (Denmark)

    Munk, Anders Kristian

    2012-01-01

    The issue of riverine flooding in the UK is closely tied up with computer simulations. Arguably, these modelling practices are ripe with the anticipation of nature. They aspire to pre-empt it, hence expect it to be ‘out there’, and ultimately work through formalized distillations of it – hydrodyn......The issue of riverine flooding in the UK is closely tied up with computer simulations. Arguably, these modelling practices are ripe with the anticipation of nature. They aspire to pre-empt it, hence expect it to be ‘out there’, and ultimately work through formalized distillations...... of it – hydrodynamic equations – which have their own anticipations and place their own demands on their modellers. Through the experience of a flood modelling apprenticeship I argue that the taking-place of such anticipations paradoxically relies on the birth of a hybrid, the model-modeller, and thus on a nature...

  15. Provincialising Nature

    DEFF Research Database (Denmark)

    Provincialising Nature: Multidisciplinary Approaches to the Politics of the Environment in Latin America offers a timely analysis of some of the crucial challenges, contradictions and promises within current environmental discourses and practices in the region. This book shows both challenging...... scenarios and original perspectives that have emerged in Latin America in relation to the globally urgent issues of climate change and the environmental crisis. Two interconnected analytical frameworks guide the discussions in the book: the relationship between nature, knowledge and identity and their role...

  16. Natural pedagogy.

    Science.gov (United States)

    Csibra, Gergely; Gergely, György

    2009-04-01

    We propose that human communication is specifically adapted to allow the transmission of generic knowledge between individuals. Such a communication system, which we call 'natural pedagogy', enables fast and efficient social learning of cognitively opaque cultural knowledge that would be hard to acquire relying on purely observational learning mechanisms alone. We argue that human infants are prepared to be at the receptive side of natural pedagogy (i) by being sensitive to ostensive signals that indicate that they are being addressed by communication, (ii) by developing referential expectations in ostensive contexts and (iii) by being biased to interpret ostensive-referential communication as conveying information that is kind-relevant and generalizable.

  17. Natural aerodynamics

    CERN Document Server

    Scorer, R S

    1958-01-01

    Natural Aerodynamics focuses on the mathematics of any problem in air motion.This book discusses the general form of the law of fluid motion, relationship between pressure and wind, production of vortex filaments, and conduction of vorticity by viscosity. The flow at moderate Reynolds numbers, turbulence in a stably stratified fluid, natural exploitation of atmospheric thermals, and plumes in turbulent crosswinds are also elaborated. This text likewise considers the waves produced by thermals, transformation of thin layer clouds, method of small perturbations, and dangers of extra-polation.Thi

  18. Cardiovascular group

    Science.gov (United States)

    Blomqvist, Gunnar

    1989-01-01

    As a starting point, the group defined a primary goal of maintaining in flight a level of systemic oxygen transport capacity comparable to each individual's preflight upright baseline. The goal of maintaining capacity at preflight levels would seem to be a reasonable objective for several different reasons, including the maintenance of good health in general and the preservation of sufficient cardiovascular reserve capacity to meet operational demands. It is also important not to introduce confounding variables in whatever other physiological studies are being performed. A change in the level of fitness is likely to be a significant confounding variable in the study of many organ systems. The principal component of the in-flight cardiovascular exercise program should be large-muscle activity such as treadmill exercise. It is desirable that at least one session per week be monitored to assure maintenance of proper functional levels and to provide guidance for any adjustments of the exercise prescription. Appropriate measurements include evaluation of the heart-rate/workload or the heart-rate/oxygen-uptake relationship. Respiratory gas analysis is helpful by providing better opportunities to document relative workload levels from analysis of the interrelationships among VO2, VCO2, and ventilation. The committee felt that there is no clear evidence that any particular in-flight exercise regimen is protective against orthostatic hypotension during the early readaptation phase. Some group members suggested that maintenance of the lower body muscle mass and muscle tone may be helpful. There is also evidence that late in-flight interventions to reexpand blood volume to preflight levels are helpful in preventing or minimizing postflight orthostatic hypotension.

  19. The importance of natural fractures in a tight reservoir for potential CO2 storage : A case study of the upper Triassic-middle Jurassic Kapp Toscana Group (Spitsbergen, Arctic Norway)

    NARCIS (Netherlands)

    Ogata, K.; Senger, K.; Braathen, A.; Tveranger, J.; Olaussen, S.

    2014-01-01

    In the Longyearbyen CO2 laboratory project, it is planned to inject carbon dioxide into a Triassic-Jurassic fractured sandstone-shale succession (Kapp Toscana Group) at a depth of 700- 1000 m below the local settlement. The targeted storage sandstones offer moderate secondary porosity and low

  20. The importance of natural fractures in a tight reservoir for potential CO2 storage: a case study of the upper Triassic-middle Jurassic Kapp Toscana Group (Spitsbergen, Arctic Norway)

    NARCIS (Netherlands)

    Ogata, K.; Senger, K.; Braathen, A.; Tveranger, J.; Olaussen, S.

    2012-01-01

    In the Longyearbyen CO2 laboratory project, it is planned to inject carbon dioxide into a Triassic–Jurassic fractured sandstone–shale succession (Kapp Toscana Group) at a depth of 700– 1000 m below the local settlement. The targeted storage sandstones offer moderate secondary porosity and low

  1. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 2. Nature Watch Decline of a Montane Ecosystem. Kartik Shanker. Feature Article Volume 2 Issue 2 February 1997 pp 75-82. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/02/0075-0082 ...

  2. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 8. Nature Watch - Hornbills – Giants Among the Forest Birds. T R Shankar Raman Divya Mudappa. Feature Article Volume 3 Issue 8 August 1998 pp 56-65. Fulltext. Click here to view fulltext PDF. Permanent link:

  3. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 9. Nature Watch - Coral Reefs and their Fauna: An Underwater Fantasyland. Anuradha Bhat. Feature Article Volume 9 Issue 9 September 2004 pp 62-73. Fulltext. Click here to view fulltext PDF. Permanent link:

  4. Nature Watch

    Indian Academy of Sciences (India)

    Annual Meetings · Mid Year Meetings · Discussion Meetings · Public Lectures · Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 7. Nature Watch - Tent-making Bats. N Gopukumar J Balasingh. Feature Article Volume 7 Issue ...

  5. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 3. Nature Watch Diversity of Bats. G Marimuthu. Feature Article Volume 1 Issue 3 March 1996 pp 103-110. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/03/0103-0110. Author Affiliations.

  6. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 5. Nature Watch Will the Meek Inherit the Earth? Kartik Shanker. Feature Article Volume 2 Issue 5 May 1997 pp 54-59. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/05/0054-0059 ...

  7. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 8. Nature Watch: On the Trail of Skinks of the Western Ghats. Anirudha Datta-Roy. Feature Article Volume 19 Issue 8 August 2014 pp 753-763. Fulltext. Click here to view fulltext PDF. Permanent link:

  8. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 3. Nature Watch Diversity of Bats. G Marimuthu. Feature Article Volume 1 Issue 3 March 1996 pp 103-110. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/03/0103-0110. Author Affiliations.

  9. Nature Watch

    Indian Academy of Sciences (India)

    After the 1960s man's attention was diverted towards the Thar ... effects also. The alluvial and inter-dunal plains have gypsiferous hard pen sediments, which are responsible for serious water logging and salinity-alkalinity problems. Moreover, natural surface drainage system is absent and the ground water is highly saline.

  10. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 8. Nature Watch - Secrets of the Shieldtails. Kartik Shanker. Feature Article Volume 1 Issue 8 August 1996 pp 64-70. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/08/0064-0070 ...

  11. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 7. Nature Watch - Singapore's Jurong BirdPark: A Study Model. Abraham Verghese. Feature Article Volume 6 Issue 7 July 2001 pp 74-88. Fulltext. Click here to view fulltext PDF. Permanent link:

  12. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 7. Nature Watch - The Odyssey of the Olive Ridley. Kartik Shanker. Feature Article Volume 4 Issue 7 July 1999 pp 68-78. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/004/07/0068-0078 ...

  13. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 12. Nature Watch - Sarus Crane: On its Way to Extinction. Alok Kumar Mishra. Feature Article Volume 14 Issue 12 December 2009 pp 1206-1209. Fulltext. Click here to view fulltext PDF. Permanent link:

  14. Kritikkens natur

    DEFF Research Database (Denmark)

    Schatz-Jakobsen, Claus

    1999-01-01

    Artiklen introducerer det nye forskningsfelt inden for samtænkning af litteratur, kultur og natur, den såkaldt økologiske kritik, og kaster et kritisk blik på  dens brug af romantisk litteratur som proto-økologisk kanon....

  15. Nature Watch

    Indian Academy of Sciences (India)

    Nature Watch - Tracking Turtles through Time and Space. Kartik Shanker. General Article Volume 7 Issue 6 June 2002 ... Keywords. Turtles; animal navigation; conservation biology; nesting behaviour; telemetry. Author Affiliations. Kartik Shanker1. Wildlife Institute of India PO Box 18, Chandrabani Dehradun 248001, India.

  16. Nature Watch

    Indian Academy of Sciences (India)

    ... Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 5. Nature Watch - Thinking Like a Tahr: When Males and Females go their Separate Ways. M D Madhusudan. Feature Article Volume 3 Issue 5 May 1998 pp 43-47 ...

  17. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 10. Nature Watch The Amazing Desert Gerbil. Ishwar Prakash. Feature Article Volume 2 Issue 10 October 1997 pp 54-61. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/10/0054-0061 ...

  18. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 3. Nature Watch: Symbiosis in Coastal Marine Communities. Neelam Pereira. Feature Article Volume 20 Issue 3 March 2015 pp 245-253. Fulltext. Click here to view fulltext PDF. Permanent link:

  19. Natural fibers

    Science.gov (United States)

    Craig M. Clemons; Daniel F. Caulfield

    2005-01-01

    The term “natural fibers” covers a broad range of vegetable, animal, and mineral fibers. However, in the composites industry, it usually refers to wood fiber and agrobased bast, leaf, seed, and stem fibers. These fibers often contribute greatly to the structural performance of the plant and, when used in plastic composites, can provide significant reinforcement. Below...

  20. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 8. Nature Watch - Secrets of the Shieldtails. Kartik Shanker. Feature Article Volume 1 Issue 8 August 1996 pp 64-70. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/08/0064-0070 ...

  1. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 10. Nature Watch - When Dragons Fly. K A Subramanian. Feature Article Volume 7 Issue 10 October 2002 pp 69-78. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/10/0069-0078 ...

  2. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 8. Nature Watch - The Treasures of the Night Sky. P N Shankar B S Shylaja. Feature Article Volume 6 Issue 8 August 2001 pp 82-89. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/006/08/0082- ...

  3. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 1. Nature Watch The Kokum Tree. M D Subash Chandran. Feature Article Volume 1 Issue 1 January 1996 pp 86-89. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/01/0086-0089 ...

  4. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 7. Nature Watch - On Observing the Night Sky. P N Shankar B S Shylaja. Feature Article Volume 6 Issue 7 July 2001 pp 89-96. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/006/07/0089-0096 ...

  5. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 4. Nature Watch The Ancient Mariners. Kartik Shanker. Feature Article Volume 1 Issue 4 April 1996 pp 50-57. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/04/0050-0057. Author Affiliations.

  6. Nature Watch

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... ... 20; Issue 1. Nature Watch: A Tale of Two Turtles. V Deepak. Feature Article Volume 20 Issue 1 January 2015 pp 47-54. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/020/01/0047-0054. Keywords. Ecology; endemic; India; turtles; tortoises; Western Ghats.

  7. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 7. Nature Watch - The Odyssey of the Olive Ridley. Kartik Shanker. Feature Article Volume 4 Issue 7 July 1999 pp 68-78. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/004/07/0068-0078 ...

  8. Trajectory grouping structure

    Directory of Open Access Journals (Sweden)

    Maike Buchin

    2015-03-01

    Full Text Available The collective motion of a set of moving entities like people, birds, or other animals, is characterized by groups arising, merging, splitting, and ending. Given the trajectories of these entities, we define and model a structure that captures all of such changes using the Reeb graph, a concept from topology. The trajectory grouping structure has three natural parameters that allow more global views of the data in group size, group duration, and entity inter-distance. We prove complexity bounds on the maximum number of maximal groups that can be present, and give algorithms to compute the grouping structure efficiently. We also study how the trajectory grouping structure can be made robust, that is, how brief interruptions of groups can be disregarded in the global structure, adding a notion of persistence to the structure. Furthermore, we showcase the results of experiments using data generated by the NetLogo flocking model and from the Starkey project. The Starkey data describe the movement of elk, deer, and cattle. Although there is no ground truth for the grouping structure in this data, the experiments show that the trajectory grouping structure is plausible and has the desired effects when changing the essential parameters. Our research provides the first complete study of trajectory group evolvement, including combinatorial,algorithmic, and experimental results.

  9. Nature as Dissonant Heritage

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    -evident. But who define and decide what kind of nature to restore? And is nature restoration not a contradiction in terms in our deeply cultivated landscapes? To examine these questions it makes sense to draw parallels between nature restoration and the concept of ‘dissonant heritage’ (Ashworth 2010), which...... concerns situations of mismatch between people and their heritage. The aim of the paper is to uncover the latent cultural dissonance in relation to nature restoration and to explain how landscape architecture could play an important role in the management of this dissonance. If one accepts that heritage...... is not the same as history, but a contemporary product shaped from history, it is clear that the same area or object could be part of different heritages, creates by different groups of people for different reasons. Heritance logically and potentially involves disinheritance – our heritage is not necessary...

  10. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2010-01-01

    The recently established CMS Communications Group, led by Lucas Taylor, has been busy in all three of its main are areas of responsibility: Communications Infrastructure, Information Systems, and Outreach and Education Communications Infrastructure The damage caused by the flooding of the CMS Centre@CERN on 21st December has been completely repaired and all systems are back in operation. Major repairs were made to the roofs, ceilings and one third of the floor had to be completely replaced. Throughout these works, the CMS Centre was kept operating and even hosted a major press event for first 7 TeV collisions, as described below. Incremental work behind the scenes is steadily improving the quality of the CMS communications infrastructure, particularly Webcasting, video conferencing, and meeting rooms at CERN. CERN/IT is also deploying a pilot service of a new videoconference tool called Vidyo, to assess whether it might provide an enhanced service at a lower cost, compared to the EVO tool currently in w...

  11. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2012-01-01

      Outreach and Education We are fortunate that our research has captured the public imagination, even though this inevitably puts us under the global media spotlight, as we saw with the Higgs seminar at CERN in December, which had 110,000 distinct webcast viewers. The media interest was huge with 71 media organisations registering to come to CERN to cover the Higgs seminar, which was followed by a press briefing with the DG and Spokespersons. This event resulted in about 2,000 generally positive stories in the global media. For this seminar, the CMS Communications Group prepared up-to-date news and public material, including links to the CMS results, animations and event displays [http://cern.ch/go/Ch8thttp://cern.ch/go/Ch8t]. There were 44,000 page-views on the CMS public website, with the Higgs news article being by far the most popular item. CMS event displays from iSpy are fast becoming the iconic media images, featuring on numerous major news outlets (BBC, CNN, MSN...) as well as in the sci...

  12. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2011-01-01

    Communications Infrastructure The 55 CMS Centres worldwide are well used by physicists working on remote CMS shifts, Computing operations, data quality monitoring, data analysis and outreach. The CMS Centre@CERN in Meyrin is particularly busy at the moment, hosting about 50 physicists taking part in the heavy-ion data-taking and analysis. Three new CMS meeting room will be equipped for videoconferencing in early 2012: 40/5B-08, 42/R-031, and 28/S-029. The CMS-TV service showing LHC Page 1, CMS Page 1, etc. (http://cmsdoc.cern.ch/cmscc/projector/index.jsp) is now also available for mobile devices: http://cern.ch/mcmstv. Figure 12: Screenshots of CMS-TV for mobile devices Information Systems CMS has a new web site: (http://cern.ch/cms) using a modern web Content Management System to ensure content and links are managed and updated easily and coherently. It covers all CMS sub-projects and groups, replacing the iCMS internal pages. It also incorporates the existing CMS public web site (http:/...

  13. Emotional collectives: How groups shape emotions and emotions shape groups.

    Science.gov (United States)

    van Kleef, Gerben A; Fischer, Agneta H

    2016-01-01

    Group settings are epicentres of emotional activity. Yet, the role of emotions in groups is poorly understood. How do group-level phenomena shape group members' emotional experience and expression? How are emotional expressions recognised, interpreted and shared in group settings? And how do such expressions influence the emotions, cognitions and behaviours of fellow group members and outside observers? To answer these and other questions, we draw on relevant theoretical perspectives (e.g., intergroup emotions theory, social appraisal theory and emotions as social information theory) and recent empirical findings regarding the role of emotions in groups. We organise our review according to two overarching themes: how groups shape emotions and how emotions shape groups. We show how novel empirical approaches break important new ground in uncovering the role of emotions in groups. Research on emotional collectives is thriving and constitutes a key to understanding the social nature of emotions.

  14. Unbounded Naturalism

    Directory of Open Access Journals (Sweden)

    Andrew Taggart

    2008-10-01

    Full Text Available nbsp;font face="Times, serif"font size="3"In the Anglo-American reception of John McDowellrsquo;s /font/fontfont face="Times, serif"font size="3"emMind and World/em/font/fontfont face="Times, serif"font size="3", there has been little attention paid to the developmental aspect of his lsquo;partially re-enchantedrsquo; naturalism. In lsquo;Naturalism Unboundedrsquo;, I argue that McDowellrsquo;s story of our normal upbringing (/font/fontfont face="Times, serif"font size="3"emBildung/em/font/fontfont face="Times, serif"font size="3" presents problems for his claim that we have a lsquo;standing obligationrsquo; to reflect on our perceptual experiences. I follow this critique up with a Hegelian-inspired attempt to retain and revise the vital points he makes about experience./font/font

  15. Jagtens natur

    DEFF Research Database (Denmark)

    Gjerris, Mickey; Borkfelt, Sune; Gamborg, Christian

    2017-01-01

    Jagt kan ses som en konfrontation mellem menneskeverdenen og den vilde natur. I dag kan det dog være svært at få øje på det vilde i naturen i et land som Danmark, hvor over 60 % af det samlede areal anvendes til landbrug, og kun få pletter er overladt til sig selv. Ikke desto mindre spiller naturen...... en stor rolle for både jægerne og for de, der forholder sig kritisk til jagt. Der er stor enighed mellem disse parter om, at naturen er noget, vi skal tage vare på – men når det kommer til, hvilken natur der sigtes til, og hvordan vi skal tage vare på den, skilles vandene. Det skal bemærkes, at vi i...

  16. Natural games

    International Nuclear Information System (INIS)

    Anttila, Jani; Annila, Arto

    2011-01-01

    A course of a game is formulated as a physical process that will consume free energy in the least time. Accordingly, the rate of entropy increase is the payoff function that will subsume all forms of free energy that motivate diverse decisions. Also other concepts of game theory are related to their profound physical counterparts. When the physical portrayal of behavior is mathematically analyzed, the course of a game is found to be inherently unpredictable because each move affects motives in the future. Despite the non-holonomic character of the natural process, the objective of consuming free energy in the least time will direct an extensive-form game toward a Lyapunov-stable point that satisfies the minimax theorem. -- Highlights: → Behavior in the context of game theory is described as a natural process. → The rate of entropy increase, derived from statistical physics of open systems, is identified as the payoff function. → Entropy as the payoff function also clarifies motives of collaboration and subjective nature of decision making. → Evolutionary equation of motion that accounts for the course of a game is inherently unpredictable.

  17. Acute and short-term hemodynamic, echocardiographic, and clinical effects of enalapril maleate in dogs with naturally acquired heart failure: results of the Invasive Multicenter PROspective Veterinary Evaluation of Enalapril study. The IMPROVE Study Group.

    Science.gov (United States)

    1995-01-01

    The efficacy of enalapril maleate in dogs with naturally acquired class III or class IV heart failure was evaluated in a multicenter study. Fifty-eight dogs with dilated cardiomyopathy (35 dogs), mitral regurgitation (22 dogs), or aortic regurgitation (1 dog) receiving conventional therapy for heart failure (furosemide with or without digoxin) were included in a randomized double-blind study. Thirty-one dogs received enalapril tablets PO at approximately 0.5 mg/kg body weight bid, and 27 dogs received placebo tablets PO bid. Physical, electrocardiographic, hemodynamic, echocardiographic, radiographic, and clinical examinations were performed on each dog before treatment and at the end of the approximately 21-day study. After treatment on day 0, the enalapril-treated dogs had significantly (P < .05) lower heart rate, mean systemic arterial blood pressure, and mean pulmonary arterial blood pressure than the placebo-treated dogs. Pulmonary capillary wedge pressure was marginally decreased (P = .0567) in the enalapril-treated dogs. When compared with those in the placebo-treated dogs, scores for pulmonary edema were significantly (P < .05) decreased on day 2 in the enalapril-treated dogs. At the end of the study, enalapril-treated dogs had significantly (P < .05) greater decreases in class of heart failure, pulmonary edema score, and mobility score relative to baseline, and had significantly (P < .05) better overall evaluation scores when compared with the placebo-treated dogs. This study shows the beneficial hemodynamic and clinical effects of adding enalapril to conventional therapy for dogs with heart failure.

  18. Nature Watch

    Indian Academy of Sciences (India)

    Admin

    in groups of around 2 to 5 in regions like wetlands, flood areas, ponds, lakes, canals, fallow and rice paddies. They form their nests around shallow water bodies where green shrubs, grasses and bushes are in abundance. Cranes are omnivorous and feed mainly on certain aquatic tubers, rhizomes, seeds and grains.

  19. of Natural

    International Development Research Centre (IDRC) Digital Library (Canada)

    Cathy Egan

    could lead the process without imposing solutions. With strong motivation and an untested new policy mandate, fishers in Quang Thai proposed forming a user group. Key village and local government officials were identified and met to review recent research data on the degradation of lagoon resources and to share ideas.

  20. Wave grouping measures

    Energy Technology Data Exchange (ETDEWEB)

    Mansard, E.; Sand, S.E.; Klinting, P.

    1989-02-01

    There are recent indications that distinct wave groupings can be found even in deep water. The main objective has been to give a statistical description suitable for the design of coastal and offshore structures and it is undertaken to make further investigations in this field by analyzing some prototype records using the concepts of run length of high waves and spectrum of squared elevation, the limitations and performances of which in nonlinear waves will be highlighted in this study. An attempt has been made to relate this wave grouping to the surge motion of a floating structure with a simple mooring arrangement and thereby to propose a motion-based grouping measure. It appears that the observed run length statistics can be suitably described by Kimura's predictions if the records are sufficiently long. Records whose duration are equal to, or less than, 0.6 h reflect a large statistical variability in the various wave grouping measures. The filter cut-off proposed in the concept of SIWEH for the estimation of Groupiness Factor appears to be too high to give meaningful contrasts with respect to prototype values of the peakedness factors. It is therefore proposed to use the Hilbert Transform of the time series and a cut-off which is relevant to the natural period of the test structure. In the absence of information about this natural period a cut-off fc less than or equal to f/sub p//15 may work better. The motion equivalent groupiness factor concept could be used effectively to determine the critical sea state conditions to be used for testing of floating structures. The directional resolution of the sea state and theoretical formulations defining statistical variabilities caused by finite record lengths could be useful in evaluating whether the wave grouping is a linear process. (AB) 49 refs.

  1. A natural grouping of motifs with an aspartate or asparagine residue forming two hydrogen bonds to residues ahead in sequence: their occurrence at alpha-helical N termini and in other situations.

    Science.gov (United States)

    Wan, W Y; Milner-White, E J

    1999-03-12

    Examination of the ways side-chain carboxylate and amide groups in high-resolution protein crystal structures form hydrogen bonds with main-chain atoms reveals that the most common category is a two-hydrogen-bond four to five residue motif with an aspartate or asparagine (Asx) at the first residue, for which we propose the name Asx-motif. Similar motifs with glutamate or glutamine residues at that position are rare. Asx-motifs occur typically as (1) a common feature of the N termini of alpha-helices called the Asx N-cap motif; (2) an independent motif, usually a beta-turn with an appropriately hydrogen-bonded Asx as the first residue; and (3) a motif incorporated in a beta-bulge loop. Asx-motifs are common, there being just under two-and-a-half in an average-sized protein subunit; of these, about 55 % are Asx N-cap motifs. Because they occur often in many situations, it seems that these motifs have an inherent propensity to form on their own rather than just being a feature stabilised at the end of a helix. Asx-motifs also occur in functionally interesting situations in aspartyl proteases, citrate synthase, EF hands, haemoglobins, lipocalins, glutathione reductase and the alpha/beta hydrolases. Copyright 1999 Academic Press.

  2. Natural relaxation

    Science.gov (United States)

    Marzola, Luca; Raidal, Martti

    2016-11-01

    Motivated by natural inflation, we propose a relaxation mechanism consistent with inflationary cosmology that explains the hierarchy between the electroweak scale and Planck scale. This scenario is based on a selection mechanism that identifies the low-scale dynamics as the one that is screened from UV physics. The scenario also predicts the near-criticality and metastability of the Standard Model (SM) vacuum state, explaining the Higgs boson mass observed at the Large Hadron Collider (LHC). Once Majorana right-handed neutrinos are introduced to provide a viable reheating channel, our framework yields a corresponding mass scale that allows for the seesaw mechanism as well as for standard thermal leptogenesis. We argue that considering singlet scalar dark matter extensions of the proposed scenario could solve the vacuum stability problem and discuss how the cosmological constant problem is possibly addressed.

  3. Natural uranium

    International Nuclear Information System (INIS)

    Ammerich, Marc; Frot, Patricia; Gambini, Denis-Jean; Gauron, Christine; Moureaux, Patrick; Herbelet, Gilbert; Lahaye, Thierry; Pihet, Pascal; Rannou, Alain

    2014-08-01

    This sheet belongs to a collection which relates to the use of radionuclides essentially in unsealed sources. Its goal is to gather on a single document the most relevant information as well as the best prevention practices to be implemented. These sheets are made for the persons in charge of radiation protection: users, radioprotection-skill persons, labor physicians. Each sheet treats of: 1 - the radio-physical and biological properties; 2 - the main uses; 3 - the dosimetric parameters; 4 - the measurement; 5 - the protection means; 6 - the areas delimitation and monitoring; 7 - the personnel classification, training and monitoring; 8 - the effluents and wastes; 9 - the authorization and declaration administrative procedures; 10 - the transport; and 11 - the right conduct to adopt in case of incident or accident. This sheet deals specifically with natural uranium

  4. Natural isotopes

    International Nuclear Information System (INIS)

    Vogel, J.C.

    1986-01-01

    14 C dates between 600 and 900 AD were obtained for early Iron Age sites in Natal, and from 1300 to 1450 AD for rock engraving sites in Bushmanland. Palaeoenvironmental data derived from the dating of samples related to sedimentary and geomorphic features in the central and northern Namib Desert enabled the production of a tentative graph for the changes in humidity in the region over the past 40000 years. These results suggest that relatively humid conditions came to an end in the Namib at ±25000 BP (before present). The increased precision of the SIRA mass spectrometer enabled the remeasurement of 13 C and 18 O in the Cango stalagmite. This data confirmed that the environmental temperatures in the Southern Cape remained constant to within ±1 o C during the past 5500 years. Techniques and applications for environmental isotopes in hydrology were developed to determine the origin and movement of ground water. Isotopic fractionation effects in light elements in nature were investigated. The 15 N/ 14 N ratio in bones of animals and humans increases in proportion to the aridity of the environment. This suggests that 15 N in bone from dated archaeological sites could be used to detect changes in past climatic conditions as naturally formed nitrate minerals are higly soluble and are only preserved in special, very dry environments. The sources and sinks of CO 2 on the South African subcontinent were also determined. The 13 C/ 12 C ratios of air CO 2 obtained suggest that the vegetation provides the major proportion of respired CO 2 . 9 refs., 1 fig

  5. Patient-initiated Electronic Messages and Quality of Care for Patients With Diabetes and Hypertension in a Large Fee-for-Service Medical Group: Results From a Natural Experiment.

    Science.gov (United States)

    McClellan, Sean R; Panattoni, Laura; Chan, Albert S; Tai-Seale, Ming

    2016-03-01

    Few studies have examined the association between patient-initiated electronic messaging (e-messaging) and clinical outcomes in fee-for-service settings. To estimate the association between patient-initiated e-messages and quality of care among patients with diabetes and hypertension. Longitudinal observational study from 2009 to 2013. In March 2011, the medical group eliminated a $60/year patient user fee for e-messaging and established a provider payment of $3-5 per patient-initiated e-message. Quality of care for patients initiating e-messages was compared before and after March 2011, relative to nonmessaging patients. Propensity score weighting accounted for differences between e-messaging and nonmessaging patients in generalized estimating equations. Large multispecialty practice in California compensating providers' fee-for-service. Patients with diabetes (N=4232) or hypertension (N=15,463) who had activated their online portal but not e-messaged before e-messaging became free. Quality of care included HEDIS-based process measures for hemoglobin (Hb) A1c, blood pressure, low-density lipoprotein (LDL), nephropathy, and retinopathy tests, and outcome measures for HbA1c, blood pressure, and LDL. E-messaging was measured as counts of patient-initiated e-message threads sent to providers. Patients were categorized into quartiles by e-messaging frequency. The probability of annually completing indicated tests increased by 1%-7% for e-messaging patients, depending on the outcome and e-messaging frequency. E-messaging was associated with small improvements in HbA1c and LDL for some patients with diabetes. Patient-initiated e-messaging may increase the likelihood of completing recommended tests, but may not be sufficient to improve clinical outcomes for most patients with diabetes or hypertension without additional interventions.

  6. Working group 4: Terrestrial

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    A working group at a Canada/USA symposium on climate change and the Arctic identified major concerns and issues related to terrestrial resources. The group examined the need for, and the means of, involving resource managers and users at local and territorial levels in the process of identifying and examining the impacts and consequences of climatic change. Climatic change will be important to the Arctic because of the magnitude of the change projected for northern latitudes; the apparent sensitivity of its terrestrial ecosystems, natural resources, and human support systems; and the dependence of the social, cultural, and economic welfare of Arctic communities, businesses, and industries on the health and quality of their environment. Impacts of climatic change on the physical, biological, and associated socio-economic environment are outlined. Gaps in knowledge needed to quantify these impacts are listed along with their relationships with resource management. Finally, potential actions for response and adaptation are presented

  7. Biogeochemical cycling and phyto- and bacterioplankton communities in a large and shallow tropical lagoon (Términos Lagoon, Mexico) under 2009-2010 El Niño Modoki drought conditions

    Science.gov (United States)

    Conan, Pascal; Pujo-Pay, Mireille; Agab, Marina; Calva-Benítez, Laura; Chifflet, Sandrine; Douillet, Pascal; Dussud, Claire; Fichez, Renaud; Grenz, Christian; Gutierrez Mendieta, Francisco; Origel-Moreno, Montserrat; Rodríguez-Blanco, Arturo; Sauret, Caroline; Severin, Tatiana; Tedetti, Marc; Torres Alvarado, Rocío; Ghiglione, Jean-François

    2017-03-01

    The 2009-2010 period was marked by an episode of intense drought known as the El Niño Modoki event. Sampling of the Términos Lagoon (Mexico) was carried out in November 2009 in order to understand the influence of these particular environmental conditions on organic matter fluxes within the lagoon's pelagic ecosystem and, more specifically, on the relationship between phyto- and bacterioplankton communities. The measurements presented here concern biogeochemical parameters (nutrients, dissolved and particulate organic matter [POM], and dissolved polycyclic aromatic hydrocarbons [PAHs]), phytoplankton (biomass and photosynthesis), and bacteria (diversity and abundance, including PAH degradation bacteria and ectoenzymatic activities). During the studied period, the water column of the Términos Lagoon functioned globally as a sink and, more precisely, as a nitrogen assimilator. This was due to the high production of particulate and dissolved organic matter (DOM), even though exportation of autochthonous matter to the Gulf of Mexico was weak. We found that bottom-up control accounted for a large portion of the variability of phytoplankton productivity. Nitrogen and phosphorus stoichiometry mostly accounted for the heterogeneity in phytoplankton and free-living prokaryote distribution in the lagoon. In the eastern part, we found a clear decoupling between areas enriched in dissolved inorganic nitrogen near the Puerto Real coastal inlet and areas enriched in phosphate (PO4) near the Candelaria estuary. Such a decoupling limited the potential for primary production, resulting in an accumulation of dissolved organic carbon and nitrogen (DOC and DON, respectively) near the river mouths. In the western part of the lagoon, maximal phytoplankton development resulted from bacterial activity transforming particulate organic phosphorus (PP) and dissolved organic phosphorus (DOP) to available PO4 and the coupling between Palizada River inputs of nitrate (NO3) and PP. The

  8. Symmetries in nature

    International Nuclear Information System (INIS)

    Mainzer, K.

    1988-01-01

    Symmetry, disymmetry, chirality etc. are well-known topics in chemistry. But they cannot only be found on the molecular level of matter. Atoms and elementary particles in physics are also characterized by particular symmetry groups. Even living organisms and populations on the macroscopic level have functional properties of symmetry. The whole physical, chemical, and biological evolution seems to be regulated by the emergence of new symmetries and the breaking down of old ones. One is reminded of Heisenberg's famous statement: 'Die letzte Wurzel der Erscheinungen ist also nicht die Materie, sondern das mathematische Gesetz, die Symmetrie, die mathematische Form' (Wandlungen in den Grundlagen der Naturwissenschaften, 1959). Historically the belief in symmetry and simplicity of nature has a long philosophical tradition from the Pythagoreans, Plato and Greek astronomers to Kepler and modern scientists. Today, 'symmetries in nature' is a common topic of mathematics, physics, chemistry, and biology. A lot of Nobel prizes were given in honour of inquiries concerning symmetries in nature. The fascination of symmetries is not only motivated by science, but by art and religion too. Therefore 'symmetris in nature' is an interdisciplinary topic which may help to overcome C.P. Snow's 'Two Cultures' of natural sciences and humanities. (author) 17 refs., 21 figs

  9. Natural gas purchasing

    International Nuclear Information System (INIS)

    Freedenthal, C.

    1993-01-01

    In recent years, natural gas has gained new momentum because of changes in marketing and regulations. The gas industry has always received an inordinate amount of regulatory control starting at the well head where the gas is produced to the consuming burner tip. Regulations have drastically impacted the availability of gas. Changes in the marketing and regulations have made the natural gas market sensitive at the point of production, the well head. Now, with plentiful supply and ease of transportation to bring the gas from the producing fields to the consumer, natural gas markets are taking advantage of the changed conditions. At the same time, new markets are developing to take advantage of the changes. This section shows consumers, especially the energy planners for large buyers of fuel, the advantages, sources and new methods of securing natural gas supplies. Background on how natural gas is produced and marketed are given. This section lists marketing sources, regulatory agencies and information groups available to help buyers and consumers of this important fuel for US industries and residences. 7 figs., 8 tabs

  10. Nature's palette: the search for natural blue colorants.

    Science.gov (United States)

    Newsome, Andrew G; Culver, Catherine A; van Breemen, Richard B

    2014-07-16

    The food and beverage industry is seeking to broaden the palette of naturally derived colorants. Although considerable effort has been devoted to the search for new blue colorants in fruits and vegetables, less attention has been directed toward blue compounds from other sources such as bacteria and fungi. The current work reviews known organic blue compounds from natural plant, animal, fungal, and microbial sources. The scarcity of blue-colored metabolites in the natural world relative to metabolites of other colors is discussed, and structural trends common among natural blue compounds are identified. These compounds are grouped into seven structural classes and evaluated for their potential as new color additives.

  11. Mother natural: Motivations and associations for consuming natural foods.

    Science.gov (United States)

    Moscato, Emily M; Machin, Jane E

    2018-02-01

    Natural is perceived as innately positive and is a widely sought-after attribute in food products. The natural food industry continues to grow in response to rising consumer demand. This qualitative study explored mothers' motivations for purchasing and consuming natural food products for themselves and their families. Mothers are an important population because of their disproportionate influence on household food consumption. We employed participant photography and a series of three weekly focus groups to derive a rich understanding of the activities surrounding and motivations behind seeking natural in everyday buying decisions. Five major themes were identified. First, natural nurtures well-being: physical, psychological, social, and emotional health. Second, natural behaves "supernaturally," allowing positive attributes to be transmitted from the source to the recipient. Third, natural is associated with authenticity, providing a sense of trust, transparency, and control. Fourth, consuming natural reinforces the socially constructed idea of a good mother. Lastly, the preference for natural does not always translate into purchase; mothers face compromises because of conflicting priorities and resources. Understanding mothers' multiple motivations provides deeper insight into the attraction for natural products. The findings have application in positioning interventions for more nutritional eating and revising regulations on the food label natural. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Natural Selection and Morality

    Directory of Open Access Journals (Sweden)

    Alejandro Rosas

    2006-12-01

    Full Text Available Resumen:En este ensayo abordo los intentos, relativamente recientes, de dar una explicación de la moralidad como adaptación por selección natural. Mi exposición tiene una introducción y cuatro partes: en la primera explico en qué consiste la paradoja del altruismo biológico. En la segunda expongo la solución que apela a la selección de grupos, recientemente resurgida; la solución que presuntamente aplicó Charles Darwin cuando formuló sus reflexiones biológicas sobre la moralidad humana. En la tercera expongo la solución sociobiológica, que opta por negar que la selección natural pueda explicar directamente la moralidad humana. La moralidad se presenta más bien como opuesta a la naturaleza diseñada por selección natural. En la cuarta parte desarrollo brevemente una explicación de la moralidad como adaptación que beneficia a los individuos. No opone la moralidad a la naturaleza, ni apela a la selección de grupos. Se sirve de un mecanismo de selección que opera a través de preferencias en la interacción social.Abstract:In this essay, I address recent attempts to account for morality as an adaptation due to natural selection. After a brief introduction, my exposition has four sections. I first explain the paradox of biological altruism. Second, I explain the solution to the paradox in terms of group selection. This solution was presumably applied by Darwin himself as he discussed human morality, and it has experienced a recent revival, though it remains suspicious to most biologists. In the third section I offer a socio-biological solution that opts for denying that morality can be explained by any form of natural selection. Morality is opposed to human nature as designed by natural selection. In the fourth, I argue for an explanation in terms of individual selection. It does not oppose morality to nature, and does not need the workings of group selection; rather, it operates through the agents’ psychological preferences

  13. Imagining Nature during Music Listening

    DEFF Research Database (Denmark)

    Bonde, Lars Ole; Beck, Bolette Daniels

    2018-01-01

    Nature, its delights and horrors, its creatures, its challenges and affordances play an underrated role in receptive music therapy, especially Guided Imagery and Music (GIM). In general, people from Western cultures are challenged in their mostly recreational relationship with nature, while ancient...... and traditional cultures worship nature as a place of holiness and wholeness. In GIM, a client or a group listens to music in a relaxed state and multi-modal imagery is evoked and supported by the music. The imagery is shared with the guide/therapist. This chapter will focus on ‘nature imagery’ in GIM through...

  14. Natural gas news; Gaz actualites

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1998-12-01

    This brochure is a compilation of practical information concerning the Gaz de France group: organization chart, daughter companies, services, economical activity, natural gas market, trade, regulations etc. A list of partners, directions, centres, groups, associations and other various organisms in relation with Gaz de France company is given. (J.S.)

  15. Common Group Problems: A Field Study.

    Science.gov (United States)

    Weinberg, Sanford B.; And Others

    1981-01-01

    A field study of a naturally functioning group (N=125) was conducted to identify common group problems. Trained observers attended group meetings and described the problems encountered. Difficulties of cohesion, leadership, sub-group formation, and personality conflict were identified. (RC)

  16. Atum: Scalable Group Communication Using Volatile Groups

    OpenAIRE

    Guerraoui, Rachid; Kermarrec, Anne-Marie; Pavlovic, Matej; Seredinschi, Dragos-Adrian

    2016-01-01

    This paper presents Atum, a group communication middleware for a large, dynamic, and hostile environment. At the heart of Atum lies the novel concept of volatile groups: small, dynamic groups of nodes, each executing a state machine replication protocol, organized in a flexible overlay. Using volatile groups, Atum scatters faulty nodes evenly among groups, and then masks each individual fault inside its group. To broadcast messages among volatile groups, Atum runs a gossip protocol across the...

  17. Nature and nature values in organic agriculture

    DEFF Research Database (Denmark)

    Hansen, Lene; Noe, Egon; Højring, Katrine

    2006-01-01

    The relationship between agriculture and nature is a centra issue in the current agricultural debate. Organic farming has ambitions and a special potential in relation to nature. Consideration for nature is part of the guiding principals of organic farming and many organic farmers are committed...... to protecting natural qualities. However, the issue of nature, landscape, and land use is not straightforward. Nature is an ambiguous concept that involves multiple interests and actors reaching far beyond farmers. The Danish research project ......

  18. H-D exchange on natural aluminosilicates of orthosilicate group

    International Nuclear Information System (INIS)

    Markevich, S.V.; Kolesnikov, I.M.

    1982-01-01

    Experimental data are presented on the effect of aluminium ion coordination in the composition of polyhedrons on the capability of polyhedrons to change the reaction rate of H-D exchange (on the example of ethylene). It is shown that at temperature lower 400 deg C the rate of isotopic exchange reaction is low. Experimental results both for irradiated and non-irradiated minerals are presented. The conclusion is made that the increase of aluminosilicates activity under radiation is connected with the presence of (AlO 4 )-tetrahedrons in the system and change of their state. (AlO 5 ) and (AlO 6 )-polyhedrons are not activated with gamma rays

  19. A natural Poincare gauge model

    International Nuclear Information System (INIS)

    Aldrovandi, R.; Pereira, J.G.

    1985-01-01

    A natural candidate model for a gauge theory for the Poincare group is discussed. It satisfies the usual electric-magnetic symmetry of gauge models and is a contraction of a gauge model for the De Sitter group. Its field equations are just the Yang-Mills equations for the Poincare group. It is shown that these equations do not follow from a Lagrangean. (Author) [pt

  20. Punctured torus groups and 2-bridge knot groups

    CERN Document Server

    Akiyoshi, Hirotaka; Wada, Masaaki; Yamashita, Yasushi

    2007-01-01

    This monograph is Part 1 of a book project intended to give a full account of Jorgensen's theory of punctured torus Kleinian groups and its generalization, with application to knot theory. Although Jorgensen's original work was not published in complete form, it has been a source of inspiration. In particular, it has motivated and guided Thurston's revolutionary study of low-dimensional geometric topology. In this monograph, we give an elementary and self-contained description of Jorgensen's theory with a complete proof. Through various informative illustrations, readers are naturally led to an intuitive, synthetic grasp of the theory, which clarifies how a very simple fuchsian group evolves into complicated Kleinian groups.

  1. From groups to geometry and back

    CERN Document Server

    Climenhaga, Vaughn

    2017-01-01

    Groups arise naturally as symmetries of geometric objects, and so groups can be used to understand geometry and topology. Conversely, one can study abstract groups by using geometric techniques and ultimately by treating groups themselves as geometric objects. This book explores these connections between group theory and geometry, introducing some of the main ideas of transformation groups, algebraic topology, and geometric group theory. The first half of the book introduces basic notions of group theory and studies symmetry groups in various geometries, including Euclidean, projective, and hyperbolic. The classification of Euclidean isometries leads to results on regular polyhedra and polytopes; the study of symmetry groups using matrices leads to Lie groups and Lie algebras. The second half of the book explores ideas from algebraic topology and geometric group theory. The fundamental group appears as yet another group associated to a geometric object and turns out to be a symmetry group using covering space...

  2. Which finite simple groups are unit groups?

    DEFF Research Database (Denmark)

    Davis, Christopher James; Occhipinti, Tommy

    2014-01-01

    We prove that if G is a finite simple group which is the unit group of a ring, then G is isomorphic to either (a) a cyclic group of order 2; (b) a cyclic group of prime order 2^k −1 for some k; or (c) a projective special linear group PSLn(F2) for some n ≥ 3. Moreover, these groups do all occur...

  3. Oklo working group meeting

    International Nuclear Information System (INIS)

    Von Maravic, H.

    1993-01-01

    Natural analogue studies have been carried out for several years in the framework of the European Community's R and D programme on radioactive waste; and within its recent fourth five-year programme on 'Management and storage of radioactive waste (1990-94)' the Community is participating in the Oklo study, natural analogue for transfer processes in a geological repository. The Oklo project is coordinated by CEA-IPSN (F) and involves laboratories from several CEA directorates (IPSN, DTA and DCC) which collaborate with other institutions from France: CREGU, Nancy; CNRS, Strasbourg and ENSMD, Fontainebleau. Moreover, institutes from non-EC member States are also taking part in the Oklo study. The second joint CEC-CEA progress meeting of the Oklo Working Group was held in April 1992 in Brussels and gave the possibility of reviewing and discussing progress made since its first meeting in February 1991 at CEA in Fontenay-aux-Roses. About 40 participants from 15 laboratories and organizations coming from France, Canada, Gabon, Japan, Sweden and the USA underline the great interest in the ongoing research activities. The meeting focused on the different tasks within the CEC-CEA Oklo project concerning (i) field survey and sampling, (ii) characterization of the source term, (iii) studies of the petrographical and geochemical system, and (iv) studies of the hydrogeological system and hydrodynamic modelling. (author) 17 papers are presented

  4. Concave 1-norm group selection.

    Science.gov (United States)

    Jiang, Dingfeng; Huang, Jian

    2015-04-01

    Grouping structures arise naturally in many high-dimensional problems. Incorporation of such information can improve model fitting and variable selection. Existing group selection methods, such as the group Lasso, require correct membership. However, in practice it can be difficult to correctly specify group membership of all variables. Thus, it is important to develop group selection methods that are robust against group mis-specification. Also, it is desirable to select groups as well as individual variables in many applications. We propose a class of concave [Formula: see text]-norm group penalties that is robust to grouping structure and can perform bi-level selection. A coordinate descent algorithm is developed to calculate solutions of the proposed group selection method. Theoretical convergence of the algorithm is proved under certain regularity conditions. Comparison with other methods suggests the proposed method is the most robust approach under membership mis-specification. Simulation studies and real data application indicate that the [Formula: see text]-norm concave group selection approach achieves better control of false discovery rates. An R package grppenalty implementing the proposed method is available at CRAN. © Published by Oxford University Press 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  5. The Cogema group in Japan

    International Nuclear Information System (INIS)

    1998-12-01

    The partnership between the Cogema group and Japan in the domain of fuel cycle started about 20 years ago and the 10 Japanese nuclear operators are all clients of the Cogema group. The 1997 turnover realized with Japan reached 3.6 billions of francs (11% of the total turnover of the group). This short paper presents briefly the nuclear program of Japan (nuclear park, spent fuels reprocessing-recycling strategy) and the contracts between Cogema and the Japanese nuclear operators (natural uranium, uranium conversion and enrichment, spent fuel reprocessing, plutonium recycle and MOX fuel production markets). (J.S.)

  6. Group Cohesion in Experiential Growth Groups

    Science.gov (United States)

    Steen, Sam; Vasserman-Stokes, Elaina; Vannatta, Rachel

    2014-01-01

    This article explores the effect of web-based journaling on changes in group cohesion within experiential growth groups. Master's students were divided into 2 groups. Both used a web-based platform to journal after each session; however, only 1 of the groups was able to read each other's journals. Quantitative data collected before and…

  7. Natural Product Molecular Fossils.

    Science.gov (United States)

    Falk, Heinz; Wolkenstein, Klaus

    The natural products synthesized by organisms that were living a long time ago gave rise to their molecular fossils. These can consist of either the original unchanged compounds or they may undergo peripheral transformations in which their skeletons remain intact. In cases when molecular fossils can be traced to their organismic source, they are termed "geological biomarkers".This contribution describes apolar and polar molecular fossils and, in particular biomarkers, along the lines usually followed in organic chemistry textbooks, and points to their bioprecursors when available. Thus, the apolar compounds are divided in linear and branched alkanes followed by alicyclic compounds and aromatic and heterocyclic molecules, and, in particular, the geoporphyrins. The polar molecular fossils contain as functional groups or constituent units ethers, alcohols, phenols, carbonyl groups, flavonoids, quinones, and acids, or are polymers like kerogen, amber, melanin, proteins, or nucleic acids. The final sections discuss the methodology used and the fundamental processes encountered by the biomolecules described, including diagenesis, catagenesis, and metagenesis.

  8. Probability groups as orbits of groups

    International Nuclear Information System (INIS)

    Bhattarai, H.N.

    2003-11-01

    The set of double cosets of a group with respect to a subgroup and the set of orbits of a group with respect to a group of automorphisms have structures which can be studied as multigroups, hypergroups or Pasch geometries. When the subgroup or the group of automorphisms are finite, the multivalued products can be provided with some weightages forming so-called Probability Groups. It is shown in this paper that some abstract probability groups can be realized as orbit spaces of groups. (author)

  9. Biology and Potential Biogeochemical Impacts of Novel Predatory Flavobacteria

    Science.gov (United States)

    2010-06-01

    experiments with natural bacterioplankton communities have indicated that at least a portion of marine flavobacteria readily attach to particle surfaces from...the latter two more closely related to the genus Olleya, see Chapter 2) from Southern Ocean bacterioplankton were specifically detected colonizing...the amendment of natural bacterioplankton with protein, though no effect was observed after starch amendment [125]. The use of 131 radioactively

  10. ATLAS Detector Interface Group

    CERN Multimedia

    Mapelli, L

    Originally organised as a sub-system in the DAQ/EF-1 Prototype Project, the Detector Interface Group (DIG) was an information exchange channel between the Detector systems and the Data Acquisition to provide critical detector information for prototype design and detector integration. After the reorganisation of the Trigger/DAQ Project and of Technical Coordination, the necessity to provide an adequate context for integration of detectors with the Trigger and DAQ lead to organisation of the DIG as one of the activities of Technical Coordination. Such an organisation emphasises the ATLAS wide coordination of the Trigger and DAQ exploitation aspects, which go beyond the domain of the Trigger/DAQ project itself. As part of Technical Coordination, the DIG provides the natural environment for the common work of Trigger/DAQ and detector experts. A DIG forum for a wide discussion of all the detector and Trigger/DAQ integration issues. A more restricted DIG group for the practical organisation and implementation o...

  11. Virtual nature environment with nature sound exposure induce stress recovery by enhanced parasympathetic activity

    DEFF Research Database (Denmark)

    Annerstedt, Matilda; Jönsson, Peter; Wallergård, Mattias

    2013-01-01

    Experimental research on stress recovery in natural environments is limited, as is study of the effect of sounds of nature. After inducing stress by means of a virtual stress test, we explored physiological recovery in two different virtual natural environments (with and without exposure to sounds...... of nature) and in one control condition. Cardiovascular data and saliva cortisol were collected. Repeated ANOVA measurements indicated parasympathetic activation in the group subjected to sounds of nature in a virtual natural environment, suggesting enhanced stress recovery may occur in such surroundings....... The group that recovered in virtual nature without sound and the control group displayed no particular autonomic activation or deactivation. The results demonstrate a potential mechanistic link between nature, the sounds of nature, and stress recovery, and suggest the potential importance of virtual reality...

  12. Stereotypes of Norwegian social groups.

    Science.gov (United States)

    Bye, Hege H; Herrebrøden, Henrik; Hjetland, Gunnhild J; Røyset, Guro Ø; Westby, Linda L

    2014-10-01

    We present a pilot study and two main studies that address the nature of stereotypes of social groups in Norway within the framework of the Stereotype Content Model (SCM). The first study focused on stereotypes of a wide range of groups across categories such as gender, age, religious conviction, socioeconomic and health status. The second study focused on stereotypes of immigrant groups. Participants (n = 244 and n = 63, respectively) rated the groups on perceived warmth, competence, status, and competition. Results from both studies support the applicability of the SCM in Norway and provides a unique insight into stereotypes of Norwegian social groups. © 2014 The Authors. Scandinavian Journal of Psychology published by Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  13. North American Natural Gas Markets

    International Nuclear Information System (INIS)

    1988-12-01

    This report sunnnarizes the research by an Energy Modeling Forum working group on the evolution of the North American natural gas markets between now and 2010. The group's findings are based partly on the results of a set of economic models of the natural gas industry that were run for four scenarios representing significantly different conditions: two oil price scenarios (upper and lower), a smaller total US resource base (low US resource case), and increased potential gas demand for electric generation (high US demand case). Several issues, such as the direction of regulatory policy and the size of the gas resource base, were analyzed separately without the use of models

  14. North American Natural Gas Markets

    International Nuclear Information System (INIS)

    1989-02-01

    This report summarizes die research by an Energy Modeling Forum working group on the evolution of the North American natural gas markets between now and 2010. The group's findings are based partly on the results of a set of economic models of the natural gas industry that were run for four scenarios representing significantly different conditions: two oil price scenarios (upper and lower), a smaller total US resource base (low US resource case), and increased potential gas demand for electric generation (high US demand case). Several issues, such as the direction of regulatory policy and the size of the gas resource base, were analyzed separately without the use of models

  15. Promoting EFL Learning through Group Dynamics | Oladunjoye ...

    African Journals Online (AJOL)

    What makes this article different from similar papers on this subject is that it centers on the elements of team work and grouping 'therapy' and not mere dividing into groups and then using some other methods to help groups learn. Rather, the paper is about the need to understand the EFL classroom and tap the nature of ...

  16. Deformation quantization of the Heisenberg group

    International Nuclear Information System (INIS)

    Bonechi, F.

    1994-01-01

    After reviewing the way the quantization of Poisson Lie Groups naturally leads to Quantum Groups, the existing quantum version H(1) q of the Heisenberg algebra is used to give an explicit example of this quantization on the Heisenberg group. (author) 6 refs

  17. Nature Inspired Surface Coatings

    Science.gov (United States)

    Rubner, Michael

    2011-04-01

    Materials Scientists more and more are looking to nature for clues on how to create highly functional surface coatings with exceptional properties. The fog harvesting capabilities of the Namib Desert beetle, the beautiful iridescent colors of the hummingbird, and the super water repellant abilities of the Lotus leaf are but a few examples of the amazing properties developed over many years in the natural world. Nature also makes extensive use of the pH-dependent behavior of weak functional groups such as carboxylic acid and amine functional groups. This presentation will explore synthetic mimics to the nano- and microstructures responsible for these fascinating properties. For example, we have demonstrated a pH-induced porosity transition that can be used to create porous films with pore sizes that are tunable from the nanometer scale to the multiple micron scale. The pores of these films, either nano- or micropores, can be reversibly opened and closed by changes in solution pH. The ability to engineer pH-gated porosity transitions in heterostructured thin films has led to the demonstration of broadband anti-reflection coatings that mimic the anti-reflection properties of the moth eye and pH-tunable Bragg reflectors with a structure and function similar to that found in hummingbird wings and the Longhorn beetle. In addition, the highly textured honeycomb-like surfaces created by the formation of micron-scale pores are ideally suited for the creation of superhydrophobic surfaces that mimic the behavior of the self-cleaning lotus leaf. The development of synthetic "backbacks" on immune system cells that may one day ferry drugs to disease sites will also be discussed.

  18. Group typicality, group loyalty and cognitive development.

    Science.gov (United States)

    Patterson, Meagan M

    2014-09-01

    Over the course of childhood, children's thinking about social groups changes in a variety of ways. Developmental Subjective Group Dynamics (DSGD) theory emphasizes children's understanding of the importance of conforming to group norms. Abrams et al.'s study, which uses DSGD theory as a framework, demonstrates the social cognitive skills underlying young elementary school children's thinking about group norms. Future research on children's thinking about groups and group norms should explore additional elements of this topic, including aspects of typicality beyond loyalty. © 2014 The British Psychological Society.

  19. Cyclic homology and group actions

    Science.gov (United States)

    Ponge, Raphaël

    2018-01-01

    In this paper we present the construction of explicit quasi-isomorphisms that compute the cyclic homology and periodic cyclic homology of crossed-product algebras associated with (discrete) group actions. In the first part we deal with algebraic crossed-products associated with group actions on unital algebras over any ring k ⊃ Q. In the second part, we extend the results to actions on locally convex algebras. We then deal with crossed-products associated with group actions on manifolds and smooth varieties. For the finite order components, the results are expressed in terms of what we call "mixed equivariant cohomology". This "mixed" theory mediates between group homology and de Rham cohomology. It is naturally related to equivariant cohomology, and so we obtain explicit constructions of cyclic cycles out of equivariant characteristic classes. For the infinite order components, we simplify and correct the misidentification of Crainic (1999). An important new homological tool is the notion of "triangular S-module". This is a natural generalization of the cylindrical complexes of Getzler-Jones. It combines the mixed complexes of Burghelea-Kassel and parachain complexes of Getzler-Jones with the S-modules of Kassel-Jones. There are spectral sequences naturally associated with triangular S-modules. In particular, this allows us to recover spectral sequences of Feigin-Tsygan and Getzler-Jones and leads us to a new spectral sequence.

  20. AREVA group overview; Presentation du groupe AREVA

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-02-08

    This document presents the Group Areva, a world nuclear industry leader, from a financial holding company to an industrial group, operating in two businesses: the nuclear energy and the components. The structure and the market of the group are discussed, as the financial assets. (A.L.B.)