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Sample records for intact soil-core microcosms

  1. INTACT SOIL-CORE MICROCOSMS FOR EVALUATING THE FATE AND ECOLOGICAL IMPACT OF THE RELEASE OF GENETICALLY ENGINEERED MICROORGANISMS

    EPA Science Inventory

    Intact soil-core microcosms were studied to determine their applicability for evaluating the transport, survival and potential ecosystem effects of genetically engineered microorganisms before they are released into the environment. oi1-core microcosms were planted with wheat and...

  2. FATE OF TN5 MUTANTS OF ROOT GROWTH-INHIBITING PSEUDOMONAS SP. IN INTACT SOIL-CORE MICROCOSMS

    EPA Science Inventory

    Transposon Tn5 mutants of a wheat root growth-inhibiting nonfluorescent Pseudomonas sp. were inoculated into intact soil-core microcosms to determine the utility of intact soil cores for evaluating the fate and transport of microorganisms in agricultural ecosystems. ransposon Tn5...

  3. Intact soil-core microcosms for evaluating the fate and ecological impact of the release of genetically engineered microorganisms

    SciTech Connect

    Fredrickson, J.K.; Van Voris, P.; Li, S.W. ); Bentjen, S.A. )

    1989-01-01

    Intact soil-core microcosms were studied to determine their applicability for evaluating the transport, survival, and potential ecosystem effects of genetically engineered microorganisms before they are released into the environment. Soil-core microcosms were planted with wheat and maize seeds and inoculated with Azospirillum lipoferum SpBr17 and SpRG20a Tn5 mutants, respectively. Microcosm leachate, rhizosphere soil, plant endorhizosphere, insects, and xylem exudate were sampled for A. lipoferum Tn5 mutant populations. A. lipoferum TN5 populations, determined by most-probable-number technique-DNA hybridization, varied from bellow detection to 10{sup 6} g of dry root{sup {minus}1} in the rhizosphere, with smaller populations detected in the endorhizosphere. Intact soil-core microcosms were found to maintain some of the complexities of the natural ecosystem and should be particularly useful for initial evaluations of the fate of plant-associated genetically engineered bacteria.

  4. EVALUATION OF INTACT SOIL-CORE MICROCOSMS FOR DETERMINING POTENTIAL IMPACTS ON NUTRIENT DYNAMICS BY GENETICALLY ENGINEERED MICROORGANISMS

    EPA Science Inventory

    Nutrient export from intact soil-core microcosms in leachate or by plant uptake was evaluated as a means to assess the ecosystem impacts from the environmental release of genetically modified root-colonizing bacteria. ntact cores of two soil types, a Burbank sandy loam and an Pal...

  5. FIELD CALIBRATION OF SOIL-CORE MICROCOSMS FOR EVALUATING FATE AND EFFECTS OF GENETICALLY ENGINEERED MICROORGANISMS IN TERRESTRIAL ECOSYSTEMS

    EPA Science Inventory

    Pacific Northwest Laboratory compared intact soil-core microcosms and the field for ecosystem structural and functional properties after the introduction of a model genetically engineered microorganism (GEM). This project used two distinct microbial types as model GEMs, Gram nega...

  6. Field calibration of soil-core microcosms for evaluating fate and effects of genetically engineered microorganisms in terrestrial ecosystems

    SciTech Connect

    Bolton, H Jr; Fredrickson, J K; Bentjen, S A; Workman, D J; Li, S W; Thomas, J M

    1991-04-01

    Pacific Northwest Laboratory compared intact soil-core microcosms and the field for ecosystem structural and functional properties after the introduction of a model genetically engineered microorganism (GEM). This project used two distinct microbial types as model GEMs, Gram-negative Pseudomonas sp. RC1, which was an aggressive root colonizer, and Gram-positive Streptomyces lividans TK24. The model GEMs were added to surface soil in separate studies, with RC1 studied throughout the growth of winter wheat (Triticum aestivum), while TK24 was studied throughout a ten month period. Also, RC1 was used in studies conducted during two consecutive field seasons (1988 to 1990) to determine how year-to-year field variability influenced the calibration of microcosms with the field. The main conclusions of this research were that intact soil-core microcosms can be useful to simulate the field for studies of microbial fate and effects on ecosystem structural and functional properties. In general, microcosms in the growth chamber, which simulated average field variations, were similar to the field for most parameters or differences could be attributed to the great extremes in temperature that occurred in the field compared to the microcosms. Better controls of environmental variables including temperature and moisture will be necessary to more closely simulate the field for future use of microcosms for risk assessment. 126 refs., 13 figs., 12 tabs.

  7. Phosphorus leaching through intact soil cores as influenced by type and duration of manure application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaching of phosphorus (P) in manure-amended soils has received increased attention as a significant source of non-point source P pollution. Intact soil cores were collected from fields on a farm in Southern New York to test the effects of long-term dairy or poultry manure application on P leaching....

  8. An improved method for field extraction and laboratory analysis of large, intact soil cores

    USGS Publications Warehouse

    Tindall, J.A.; Hemmen, K.; Dowd, J.F.

    1992-01-01

    Various methods have been proposed for the extraction of large, undisturbed soil cores and for subsequent analysis of fluid movement within the cores. The major problems associated with these methods are expense, cumbersome field extraction, and inadequate simulation of unsaturated flow conditions. A field and laboratory procedure is presented that is economical, convenient, and simulates unsaturated and saturated flow without interface flow problems and can be used on a variety of soil types. In the field, a stainless steel core barrel is hydraulically pressed into the soil (30-cm diam. and 38 cm high), the barrel and core are extracted from the soil, and after the barrel is removed from the core, the core is then wrapped securely with flexible sheet metal and a stainless mesh screen is attached to the bottom of the core for support. In the laboratory the soil core is set atop a porous ceramic plate over which a soil-diatomaceous earth slurry has been poured to assure good contact between plate and core. A cardboard cylinder (mold) is fastened around the core and the empty space filled with paraffin wax. Soil cores were tested under saturated and unsaturated conditions using a hanging water column for potentials ???0. Breakthrough curves indicated that no interface flow occurred along the edge of the core. This procedure proved to be reliable for field extraction of large, intact soil cores and for laboratory analysis of solute transport.

  9. Experimental terrestrial soil-core microcosm test protocol. A method for measuring the potential ecological effects, fate, and transport of chemicals in terrestrial ecosystems

    SciTech Connect

    Van Voris, P.; Tolle, D.A.; Arthur, M.F.

    1985-06-01

    In order to protect the environment properly and have a realistic appraisal of how a chemical will act in the environment, tests of ecological effects and chemical fate must be performed on complex assemblages of biotic and abiotic components (i.e., microcosms) as well as single species. This protocol is one which could be added to a series of tests recently developed as guidelines for Section 4 of the Toxic Substances Control Act (P.L. 94-469; U.S.C., Section 2601-2629). The terrestrial soil-core microcosm is designed to supply site-specific and possibly regional information on the probable chemical fate and ecological effects resulting from release of a chemical substance to a terrestrial ecosystem. The EPA will use the data resulting from this test system to compare the potential hazards of a chemical with others that have been previously evaluated.

  10. Comparative community responses to elevated atmospheric CO{sub 2} in microcosms and intact grassland

    SciTech Connect

    Chiariello, N.R.

    1995-06-01

    Ecosystem responses to elevated CO{sub 2} involve components that are difficult to resolve in spatially varying, intact systems. Depending on their functional similarity to the field, experimental microcosms may provide more uniform, accessible analogues. At Stanford University`s Jasper Ridge Biological Preserve, research on grassland responses to elevated CO{sub 2} combines field studies and microcosm experiments on annual communities established from seed. Parallel measurements from year 3 of CO{sub 2} treatments in the field and year 2 in the microcosms (after self-seeding) provide a test of their functional similarity. In both, nutrient-poor serpentine soils supported high plant density (>10,000 m{sup -2}), diverse phenology, and low aboveground production (100-200 g m{sup -2}). Elevated CO{sub 2} (720 ppm) favored late-flowering, taprooted annuals in both and had little or no effect on early annuals. Exotic species that were rare in field plots were lost from microcosms by year 2. Annual grasses contributed more to production in microcosms than in the field.

  11. Leaching of Cryptosporidium parvum Oocysts, Escherichia coli, and a Salmonella enterica Serovar Typhimurium Bacteriophage through Intact Soil Cores following Surface Application and Injection of Slurry▿

    PubMed Central

    Forslund, Anita; Markussen, Bo; Toenner-Klank, Lise; Bech, Tina B.; Jacobsen, Ole Stig; Dalsgaard, Anders

    2011-01-01

    Increasing amounts of livestock manure are being applied to agricultural soil, but it is unknown to what extent this may be associated with contamination of aquatic recipients and groundwater if microorganisms are transported through the soil under natural weather conditions. The objective of this study was therefore to evaluate how injection and surface application of pig slurry on intact sandy clay loam soil cores influenced the leaching of Salmonella enterica serovar Typhimurium bacteriophage 28B, Escherichia coli, and Cryptosporidium parvum oocysts. All three microbial tracers were detected in the leachate on day 1, and the highest relative concentration was detected on the fourth day (0.1 pore volume). Although the concentration of the phage 28B declined over time, the phage was still found in leachate at day 148. C. parvum oocysts and chloride had an additional rise in the relative concentration at a 0.5 pore volume, corresponding to the exchange of the total pore volume. The leaching of E. coli was delayed compared with that of the added microbial tracers, indicating a stronger attachment to slurry particles, but E. coli could be detected up to 3 months. Significantly enhanced leaching of phage 28B and oocysts by the injection method was seen, whereas leaching of the indigenous E. coli was not affected by the application method. Preferential flow was the primary transport vehicle, and the diameter of the fractures in the intact soil cores facilitated transport of all sizes of microbial tracers under natural weather conditions. PMID:21948848

  12. N2O, NO, N2, and CO2 emissions from tropical savanna and grassland of Northern Australia: an incubation experiment with intact soil cores

    NASA Astrophysics Data System (ADS)

    Werner, C.; Reiser, K.; Dannenmann, M.; Hutley, L. B.; Jacobeit, J.; Butterbach-Bahl, K.

    2014-06-01

    Strong seasonal variability of hygric and thermal soil conditions are a defining environmental feature in Northern Australia. However, how such changes affect the soil-atmosphere exchange of nitrous oxide (N2O), nitric oxide (NO) and dinitrogen (N2) is still not well explored. By incubating intact soil cores from four sites (3 savanna, 1 pasture) under controlled soil temperatures (ST) and soil moisture (SM) we investigated the release of the trace gas fluxes of N2O, NO and carbon dioxide (CO2). Furthermore, the release of N2 due to denitrification was measured using the helium gas flow soil core technique. Under dry pre-incubation conditions NO and N2O emission were very low (<7.0 ± 5.0 μg NO-N m-2 h-1; <0.0 ± 1.4 μg N2O-N m-2 h-1) or in case of N2O, even a net soil uptake was observed. Substantial NO (max: 306.5 μg N m-2 h-1) and relatively small N2O pulse emissions (max: 5.8 ± 5.0 μg N m-2 h-1) were recorded following soil wetting, but these pulses were short-lived, lasting only up to 3 days. The total atmospheric loss of nitrogen was dominated by N2 emissions (82.4-99.3% of total N lost), although NO emissions contributed almost 43.2% at 50% SM and 30 °C ST. N2O emissions were systematically higher for 3 of 12 sample locations, which indicates substantial spatial variability at site level, but on average soils acted as weak N2O sources or even sinks. Emissions were controlled by SM and ST for N2O and CO2, ST and pH for NO, and SM and pH for N2.

  13. N2O, NO, N2 and CO2 emissions from tropical savanna and grassland of northern Australia: an incubation experiment with intact soil cores

    NASA Astrophysics Data System (ADS)

    Werner, C.; Reiser, K.; Dannenmann, M.; Hutley, L. B.; Jacobeit, J.; Butterbach-Bahl, K.

    2014-11-01

    Strong seasonal variability of hygric and thermal soil conditions are a defining environmental feature in northern Australia. However, how such changes affect the soil-atmosphere exchange of nitrous oxide (N2O), nitric oxide (NO) and dinitrogen (N2) is still not well explored. By incubating intact soil cores from four sites (three savanna, one pasture) under controlled soil temperatures (ST) and soil moisture (SM) we investigated the release of the trace gas fluxes of N2O, NO and carbon dioxide (CO2). Furthermore, the release of N2 due to denitrification was measured using the helium gas flow soil core technique. Under dry pre-incubation conditions NO and N2O emissions were very low (<7.0 ± 5.0 μg NO-N m-2 h-1; <0.0 ± 1.4 μg N2O-N m-2 h-1) or in the case of N2O, even a net soil uptake was observed. Substantial NO (max: 306.5 μg N m-2 h-1) and relatively small N2O pulse emissions (max: 5.8 ± 5.0 μg N m-2 h-1) were recorded following soil wetting, but these pulses were short lived, lasting only up to 3 days. The total atmospheric loss of nitrogen was generally dominated by N2 emissions (82.4-99.3% of total N lost), although NO emissions contributed almost 43.2% to the total atmospheric nitrogen loss at 50% SM and 30 °C ST incubation settings (the contribution of N2 at these soil conditions was only 53.2%). N2O emissions were systematically higher for 3 of 12 sample locations, which indicates substantial spatial variability at site level, but on average soils acted as weak N2O sources or even sinks. By using a conservative upscale approach we estimate total annual emissions from savanna soils to average 0.12 kg N ha-1 yr-1 (N2O), 0.68 kg N ha-1 yr-1 (NO) and 6.65 kg N ha-1 yr-1 (N2). The analysis of long-term SM and ST records makes it clear that extreme soil saturation that can lead to high N2O and N2 emissions only occurs a few days per year and thus has little impact on the annual total. The potential contribution of nitrogen released due to pulse events

  14. Evaluating the mobility of polymer-stabilised zero-valent iron nanoparticles and their potential to co-transport contaminants in intact soil cores.

    PubMed

    Chekli, L; Brunetti, G; Marzouk, E R; Maoz-Shen, A; Smith, E; Naidu, R; Shon, H K; Lombi, E; Donner, E

    2016-09-01

    The use of zero-valent iron nanoparticles (nZVI) has been advocated for the remediation of both soils and groundwater. A key parameter affecting nZVI remediation efficacy is the mobility of the particles as this influences the reaction zone where remediation can occur. However, by engineering nZVI particles with increased stability and mobility we may also inadvertently facilitate nZVI-mediated contaminant transport away from the zone of treatment. Previous nZVI mobility studies have often been limited to model systems as the presence of background Fe makes detection and tracking of nZVI in real systems difficult. We overcame this problem by synthesising Fe-59 radiolabelled nZVI. This enabled us to detect and quantify the leaching of nZVI-derived Fe-59 in intact soil cores, including a soil contaminated by Chromated-Copper-Arsenate. Mobility of a commercially available nZVI was also tested. The results showed limited mobility of both nanomaterials; <1% of the injected mass was eluted from the columns and most of the radiolabelled nZVI remained in the surface soil layers (the primary treatment zone in this contaminated soil). Nevertheless, the observed breakthrough of contaminants and nZVI occurred simultaneously, indicating that although the quantity transported was low in this case, nZVI does have the potential to co-transport contaminants. These results show that direct injection of nZVI into the surface layers of contaminated soils may be a viable remediation option for soils such as this one, in which the mobility of nZVI below the injection/remediation zone was very limited. This Fe-59 experimental approach can be further extended to test nZVI transport in a wider range of contaminated soil types and textures and using different application methods and rates. The resulting database could then be used to develop and validate modelling of nZVI-facilitated contaminant transport on an individual soil basis suitable for site specific risk assessment prior to n

  15. Evaluation of terrestrial microcosms for assessing the fate and effects of genetically engineered microorganisms on ecological processes

    SciTech Connect

    Fredrickson, J.K.; Bentjen, S.A.; Bolton, H. Jr.; Li, S.W.; Ligotke, M.W.; McFadden, K.M.; Van Voris, P.

    1989-04-01

    This project evaluates and modifies the existing US Environmental Protection Agency's Office of Pesticides and Toxic Substances (EPA/OPTS) terrestrial microcosm test system and test protocols such that they can be used to determine the environmental fate and ecological hazards of genetically engineered microorganisms (GEMs). The intact soil-core microcosm represents terrestrial ecosystems, and when coupled with appropriate test protocols, such microcosms may be appropriate to define and limit risks associated with the intentional release of GEMs. The terrestrial microcosm test system was used to investigate the survival and transport of two model GEMs (Azospirillum lipoferum and Pseudomonas sp. Tn5 mutants) to various trophic levels and niches and through intact soil cores. Subsequent effects on nutrient cycling and displacement of indigenous microorganisms were evaluated. The model organisms were a diazotrophic root-colonizing bacterium (A. lipoferum) and a wheat root growth-inhibiting rhizobacterium (Pseudomonas sp.). The transposable element Tn5 was used as a genetic marker for both microorganisms in two separate experiments. The organisms were subjected to transposon mutagenesis using a broad host-range-mobilizable suicide plasmid. The transposon Tn5 conferred levels of kanamycin resistance up to 500 ..mu..g/ml (Pseudomonas sp.), which allowed for selection of the bacteria from environmental samples. The presence of Tn5 DNA in the genome of the model GEMs also allowed the use of Tn5 gene probes to confirm and enumerate the microorganisms in different samples from the microcosms. Two types of root growth-inhibiting Pseudomonas sp. Tn5 mutants were obtained and used in microcosm studies: those that lacked the ability to inhibit either wheat root growth or the growth of other microorganisms in vitro (tox/sup /minus//) and those which retained these properties (tox/sup +/). 53 refs., 7 figs., 6 tabs.

  16. COMPARISON OF MICROBIAL TROPHIC INTERACTIONS IN AQUATIC MICROCOSMS DESIGNED FOR THE TESTING OF INTRODUCED MICROORGANISMS

    EPA Science Inventory

    Two aquatic microcosms of different complexity were calibrated with a eutrophic lake. he simple microcosm consisted of an intact sediment core with overlying water. he complex microcosm was compartmentalized (phytoplankton tank, grazer tank, and sediment cores) to allow manipulat...

  17. Evaluation of terrestrial microcosms for detection, fate, and survival analysis of genetically engineered microorganisms and their recombinant genetic material

    SciTech Connect

    Fredrickson, J.K.; Seidler, R.J.

    1989-02-01

    The research included in this document represents the current scientific information available regarding the applicability of terrestrial microcosms and related methodologies for evaluating detection methods and the fate and survival of microorganisms in the environment. The three terrestrial microcosms described in this document were used to evaluate the survival and fate of recombinant bacteria in soils and in association with plant surfaces and insects and their transport through soil with percolating water and root systems, and to test new methods and procedures to improve detection and enumeration of bacteria in soil. Simple (potting soil composed of peat mix and perlite, lacking environmental control and monitoring) and complex microcosms (agricultural soil with partial control and monitoring of environmental conditions) were demonstrated to be useful tools for preliminary assessments of microbial viability in terrestrial ecosystems. These studies evaluated the survival patterns of Enterobacter cloacae (pBR322) in soil and on plant surfaces and the ingestion of this same microorganism by cutworms and survival in the foregut and frass. The Versacore microcosm design was used to monitor the fate and competitiveness of genetically engineered bacteria in soil. Both selective media and gene probes were used successfully to follow the fate of two recombinant Pseudomonas sp. introduced into Versacore microcosms. Intact soil-core microcosms were employed to evaluate the fate and transport of genetically altered Azospirillum sp. and Pseudomonas sp. in soil and the plant rhizosphere. The usefulness of these various microcosms as a tool for risk assessment is underscored by the ease in obtaining soil from a proposed field release site to evaluate subsequent GEM fate and survival.

  18. Nitrate Reduction in a Groundwater Microcosm Determined by 15N Gas Chromatography-Mass Spectrometry

    PubMed Central

    Bengtsson, Göran; Annadotter, Heléne

    1989-01-01

    Aerobic and anaerobic groundwater continuous-flow microcosms were designed to study nitrate reduction by the indigenous bacteria in intact saturated soil cores from a sandy aquifer with a concentration of 3.8 mg of NO3−-N liter−1. Traces of 15NO3− were added to filter-sterilized groundwater by using a Darcy flux of 4 cm day−1. Both assimilatory and dissimilatory reduction rates were estimated from analyses of 15N2, 15N2O, 15NH4+, and 15N-labeled protein amino acids by capillary gas chromatography-mass spectrometry. N2 and N2O were separated on a megabore fused-silica column and quantified by electron impact-selected ion monitoring. NO3− and NH4+ were analyzed as pentafluorobenzoyl amides by multiple-ion monitoring and protein amino acids as their N-heptafluorobutyryl isobutyl ester derivatives by negative ion-chemical ionization. The numbers of bacteria and their [methyl-3H]thymidine incorporation rates were simultaneously measured. Nitrate was completely reduced in the microcosms at a rate of about 250 ng g−1 day−1. Of this nitrate, 80 to 90% was converted by aerobic denitrification to N2, whereas only 35% was denitrified in the anaerobic microcosm, where more than 50% of NO3− was reduced to NH4+. Assimilatory reduction was recorded only in the aerobic microcosm, where N appeared in alanine in the cells. The nitrate reduction rates estimated for the aquifer material were low in comparison with rates in eutrophic lakes and coastal sediments but sufficiently high to remove nitrate from an uncontaminated aquifer of the kind examined in less than 1 month. PMID:16348048

  19. Temperature effects on propylene glycol-contaminated soil cores

    SciTech Connect

    Davis-Hoover, W.J.; Vesper, S.J.

    1995-12-31

    The authors are examining the effect of temperature on the biodegradation of propylene glycol (PPG) in subsurface soil cores. Subsurface soils were contaminated in situ with PPG and allowed to diffuse into the soil for 30 days. The treated soil was reexposed, and intact were incubated for 30 days at temperatures ranging from 9 to 39 C in a temperature gradient incubator. At 30 days, soil moisture, soil pH, microbial activity [fluorescein diacetate (FDA) test], R2A plate counts, and plate counts of PPG degraders were studied. Although the soil moisture and pH remained relatively unchanged, the parameters of microbial activity varied rather consistently with temperature. Multiple populations or subpopulations of bacteria appear to exist between temperatures of 9 and 39 C in these soils.

  20. ELUTRIATOR/MICROCOSM SYSTEM PILOT MODEL AND TEST

    EPA Science Inventory

    An effective technique is described for transferring soft benthic sediments with their resident infauna intact into special holding systems (elutriator/microcosms) which permitted the study under controlled conditions of both nutrient exchange from the sediments and the activitie...

  1. The University as Microcosm

    ERIC Educational Resources Information Center

    Kaldis, Byron

    2009-01-01

    This paper puts forward the model of "microcosm-macrocosm" isomorphism encapsulated in certain philosophical views on the form of university education. The human being as a "microcosm" should reflect internally the external "macrocosm". Higher Education is a socially instituted attempt to guide human beings into forming themselves as microcosms of…

  2. Apollo rocks, fines and soil cores

    NASA Astrophysics Data System (ADS)

    Allton, J.; Bevill, T.

    Apollo rocks and soils not only established basic lunar properties and ground truth for global remote sensing, they also provided important lessons for planetary protection (Adv. Space Res ., 1998, v. 22, no. 3 pp. 373-382). The six Apollo missions returned 2196 samples weighing 381.7 kg, comprised of rocks, fines, soil cores and 2 gas samples. By examining which samples were allocated for scientific investigations, information was obtained on usefulness of sampling strategy, sampling devices and containers, sample types and diversity, and on size of sample needed by various disciplines. Diversity was increased by using rakes to gather small rocks on the Moon and by removing fragments >1 mm from soils by sieving in the laboratory. Breccias and soil cores are diverse internally. Per unit weight these samples were more often allocated for research. Apollo investigators became adept at wringing information from very small sample sizes. By pushing the analytical limits, the main concern was adequate size for representative sampling. Typical allocations for trace element analyses were 750 mg for rocks, 300 mg for fines and 70 mg for core subsamples. Age-dating and isotope systematics allocations were typically 1 g for rocks and fines, but only 10% of that amount for core depth subsamples. Historically, allocations for organics and microbiology were 4 g (10% for cores). Modern allocations for biomarker detection are 100mg. Other disciplines supported have been cosmogenic nuclides, rock and soil petrology, sedimentary volatiles, reflectance, magnetics, and biohazard studies . Highly applicable to future sample return missions was the Apollo experience with organic contamination, estimated to be from 1 to 5 ng/g sample for Apollo 11 (Simonheit &Flory, 1970; Apollo 11, 12 &13 Organic contamination Monitoring History, U.C. Berkeley; Burlingame et al., 1970, Apollo 11 LSC , pp. 1779-1792). Eleven sources of contaminants, of which 7 are applicable to robotic missions, were

  3. A Protocol for Collecting and Constructing Soil Core Lysimeters.

    PubMed

    Saporito, Louis S; Bryant, Ray B; Kleinman, Peter J A

    2016-01-01

    Leaching of nutrients from land applied fertilizers and manure used in agriculture can lead to accelerated eutrophication of surface water. Because the landscape has complex and varied soil morphology, an accompanying disparity in flow paths for leachate through the soil macropore and matrix structure is present. The rate of flow through these paths is further affected by antecedent soil moisture. Lysimeters are used to quantify flow rate, volume of water and concentration of nutrients leaching downward through soils. While many lysimeter designs exist, accurately determining the volume of water and mass balance of nutrients is best accomplished with bounded lysimeters that leave the natural soil structure intact. Here we present a detailed method for the extraction and construction of soil core lysimeters equipped with soil moisture sensors at 5 cm and 25 cm depths. Lysimeters from four different Coastal Plain soils (Bojac, Evesboro, Quindocqua and Sassafras) were collected on the Delmarva Peninsula and moved to an indoor climate controlled facility. Soils were irrigated once weekly with the equivalent of 2 cm of rainfall to draw down soil nitrate-N concentrations. At the end of the draw down period, poultry litter was applied (162 kg TN ha(-1)) and leaching was resumed for an additional five weeks. Total recovery of applied irrigation water varied from 71% to 85%. Nitrate-N concentration varied over the course of the study from an average of 27.1 mg L(-1) before litter application to 40.3 mg L(-1) following litter application. While greatest flux of nutrients was measured in soils dominated by coarse sand (Sassafras) the greatest immediate flux occurred from the finest textured soil with pronounced macropore development (Quindocqua). PMID:27341654

  4. Atmospheric carbonyl sulfide exchange in bog microcosms

    SciTech Connect

    Fried, A.; Klinger, L.F.; Erickson, D.J. III )

    1993-01-22

    Measurements of Carbonyl sulfide (OCS) fluxes were carried out on bog microcosms using chamber sampling and tunable diode laser analysis. Intact bog microcosms (vascular plants, mosses, and peat) removed ambient levels of OCS in the light and dark with rates from [minus]2.4 to [minus]8.1 ng S min[sup [minus]1] m[sup [minus]2]. Peat and peat plus mosses emitted OCS in the light with rates of 17.4 and 10.9 ng S min[sup [minus]1] m[sup [minus]2], respectively. In the dark, the mosses apparently removed OCS at a rate equivalent to the peat emissions. A 3-D numerical tracer model using this data indicated that boreal bog ecosystems remove at most 1% of ambient OCS, not sufficient to account for an observed OCS depletion in boreal air masses. 13 refs., 1 fig., 1 tab.

  5. Extending the Marine Microcosm Laboratory

    ERIC Educational Resources Information Center

    Ryswyk, Hal Van; Hall, Eric W.; Petesch, Steven J.; Wiedeman, Alice E.

    2007-01-01

    The traditional range of marine microcosm laboratory experiments is presented as an ideal environment to teach the entire analysis process. The microcosm lab provides student-centered approach with opportunities for collaborative learning and to develop critical communication skills.

  6. A Natal Microcosm

    NASA Technical Reports Server (NTRS)

    2004-01-01

    In the quest to better understand the birth of stars and the formation of new worlds, astronomers have used NASA's Spitzer Space Telescope to examine the massive stars contained in a cloudy region called Sharpless 140. This cloud is a fascinating microcosm of a star-forming region since it exhibits, within a relatively small area, all of the classic manifestations of stellar birth.

    Sharpless 140 lies almost 3000 light-years from Earth in the constellation Cepheus. At its heart is a cluster of three deeply embedded young stars, which are each several thousand times brighter than the Sun. Though they are strikingly visible in this image from Spitzer's infrared array camera, they are completely obscured in visible light, buried within the core of the surrounding dust cloud.

    The extreme youth of at least one of these stars is indicated by the presence of a stream of gas moving at high velocities. Such outflows are signatures of the processes surrounding a star that is still gobbling up material as part of its formation.

    The bright red bowl, or arc, seen in this image traces the outer surface of the dense dust cloud encasing the young stars. This arc is made up primarily of organic compounds called polycyclic aromatic hydrocarbons, which glow on the surface of the cloud. Ultraviolet light from a nearby bright star outside of the image is 'eating away' at these molecules. Eventually, this light will destroy the dust envelope and the masked young stars will emerge.

    This false-color image was taken on Oct. 11, 2003 and is composed of photographs obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

  7. Atrazine remediation in wetland microcosms.

    PubMed

    Runes, H B; Bottomley, P J; Lerch, R N; Jenkins, J J

    2001-05-01

    Laboratory wetland microcosms were used to study treatment of atrazine in irrigation runoff by a field-scale-constructed wetland under controlled conditions. Three experiments, in which 1 ppm atrazine was added to the water column of three wetland, one soil control, and one water control microcosm, were conducted. Atrazine dissipation from the water column and degradate formation (deethylatrazine [DEA]; deisopropylatrazine [DIA]; and hydroxyatrazine [HA]) were monitored. Atrazine dissipation from the water column of wetland microcosms was biphasic. Less than 12% of the atrazine applied to wetland microcosms remained in the water column on day 56. Atrazine degradates were observed in water and sediment, with HA the predominant degradate. Analysis of day 56 sediment samples indicated that a significant portion of the initial application was detected as the parent compound and HA. Most probable number (MPN) assays demonstrated that atrazine degrader populations were small in wetland sediment. Wetland microcosms were able to reduce atrazine concentration in the water column via sorption and degradation. Based on results from this study, it is hypothesized that plant uptake contributed to atrazine dissipation from the water column. PMID:11337869

  8. Using Microcosms To Teach about the Environment.

    ERIC Educational Resources Information Center

    Kaufman, Donald G.; Taylor, Lisa

    A microcosm is a small, completely sealed, self-sustaining ecosystem. Once a microcosm has been sealed in a transparent container, only light and some heat can enter and only excess heat can leave. This manual describes how to set up aquatic microcosms using glass jars and little or no collecting equipment. The activities can be tailored to suit…

  9. Sorption and photo degradation processes govern distribution of sulfamethazine in freshwater-sediment microcosms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antibiotic sulfamethazine can be transported from manured fields to surface water bodies. We investigated the degradation and fate of sulfamethazine in surface water using 14C-phenyl-sulfamethazine in small pond water microcosms containing intact sediment and pond water. We found a 2.7-d half-li...

  10. PRODUCTION CYCLES IN AQUATIC MICROCOSMS

    EPA Science Inventory

    Four 700-liter cylindrical containers were filled with demineralized water, enriched with nutrients, and inoculated with 3.5-liter lakewater samples. The microcosms were maintained at a temperature of 18C under a 12:12 L:D cycle for 6 months and several manipulations of their tro...

  11. Know Thyself: Macrocosm and Microcosm

    ERIC Educational Resources Information Center

    Tubbs, Nigel

    2011-01-01

    There was a time when, in the Liberal Arts, philosophy and education enjoyed the most intimate and productive relationship. Drawing together philosophy and nature they sought to understand the greatest of human mysteries. This meant thinking about both the macrocosm and the microcosm and especially the relation between them. In this relation lies…

  12. Uranium transformations in static microcosms.

    SciTech Connect

    Kelly, S. D.; Wu, W.; Yang, F.; Criddle, C.; Marsh, T. L.; O'Loughlin, E. J.; Ravel, B.; Watson, D.; Jardine, P. M.; Kemner, K. M.; Stanford Univ.; Michigan State Univ.; ORNL; BNL; EXAFS Analysis

    2010-01-01

    Elucidation of complex biogeochemical processes and their effects on speciation of U in the subsurface is critical for developing remediation strategies with an understanding of stability. We have developed static microcosms that are similar to bioreduction process studies in situ under laminar flow conditions or in sediment pores. Uranium L{sub 3}-edge X-ray absorption near-edge spectroscopy analysis with depth in the microcosms indicated that transformation of U{sup VI} to U{sup IV} occurred by at least two distinct processes. Extended X-ray absorption fine structure (EXAFS) analysis indicated that initial U{sup VI} species associated with C- and P-containing ligands were transformed to U{sup IV} in the form of uraninite and U associated with Fe-bound ligands. Microbial community analysis identified putative Fe{sup III} and sulfate reducers at two different depths in the microcosms. The slow reduction of U{sup VI} to U{sup IV} may contribute the stability of U{sup IV} within microcosms at 11 months after a decrease in bioreducing conditions due to limited electron donors.

  13. SOIL-SOILN simulations of water drainage and nitrate nitrogen transport from soil core lysimeters.

    PubMed

    Jabro, J D; Stout, W L; Fales, S L; Fox, R H

    2001-01-01

    Water resources protection from nitrate nitrogen (NO3-N) contamination is an important public concern and a major national environmental issue. The abilities of the SOIL-SOILN model to simulate water drainage and nitrate N fluxes from orchardgrass (Dactylis glomerata L.) were evaluated using data from a 3-yr field experiment. The soil is classified as a Hagerstown silt loam soil (fine, mixed, semiactive, mesic Typic Hapludalf). Nitrate losses below the 1-m depth from N-fertilized grazed orchardgrass were measured with intact soil core lysimeters. Five N-fertilizer treatments consisted of a control, urine application in the spring, urine application in the summer, urine application in the fall, and feces application in the summer. The SOIL-SOILN models were evaluated using water drainage and nitrate flux data for 1993-1994, 1994-1995, and 1995-1996. The N rate constants from a similar experiment with inorganic fertilizer and manure treatments under corn (Zea mays L.) were used to evaluate the SOILN model under orchardgrass sod. Results indicated that the SOIL model accurately simulated water drainage for all three years. The SOILN model adequately predicted nitrate losses for three urine treatments in each year and a control treatment in 1994-1995. However, it failed to produce accurate simulations for two control treatments in 1993-1994 and 1995-1996, and feces treatments in all three years. The inaccuracy in the simulation results for the control and feces treatments seems to be related to an inadequate modeling of N transformation processes. In general, the results demonstrate the potential of the SOILN model to predict NO3-N fluxes under pasture conditions using N transformation rate constants determined through the calibration process from corn fields on similar soils. PMID:11285920

  14. Infiltration characteristics of non-aqueous phase liquids in undisturbed loessal soil cores.

    PubMed

    Wang, Yunqiang; Shao, Ming'an

    2009-01-01

    The widespread contamination of soils and aquifers by non-aqueous phase liquids (NAPL), such as crude oil, poses serious environmental and health hazards globally. Understanding the infiltration characteristics of NAPL in soil is crucial in mitigating or remediating soil contamination. The infiltration characteristics of crude and diesel oils into undisturbed loessal soil cores, collected in polymethyl methacrylate cylindrical columns, were investigated under a constant fluid head (3 cm) of either crude oil or diesel oil. The infiltration rate of both crude and diesel oils decreased exponentially as wetting depth increased with time. Soil core size and bulk density both had significant effects on NAPL infiltration through the undisturbed soil cores; a smaller core size or a greater bulk density could reduce oil penetration to depth. Compacting soil in areas susceptible to oil spills may be an effective stratage to reduce contamination. The infiltration of NAPL into soil cores was spatially anisotropic and heterogeneous, thus recording the data at four points on the soil core is a good stratage to improve the accuracy of experimental results. Our results revealed that crude and diesel oils, rather than their components, have a practical value for remediation of contaminated loessal soils. PMID:19999998

  15. EFFICIENCY OF SOIL CORE AND SOIL-PORE WATER SAMPLING SYSTEMS

    EPA Science Inventory

    A laboratory column and field lysimeter study were conducted to evaluate the efficiency of soil core and soil-pore water samples to detect the migration of the organic components of land treated wastes through soil. In the laboratory, column leaching studies were performed by pac...

  16. A portable fluorescence spectroscopy imaging system for automated root phenotyping in soil cores in the field.

    PubMed

    Wasson, Anton; Bischof, Leanne; Zwart, Alec; Watt, Michelle

    2016-02-01

    Root architecture traits are a target for pre-breeders. Incorporation of root architecture traits into new cultivars requires phenotyping. It is attractive to rapidly and directly phenotype root architecture in the field, avoiding laboratory studies that may not translate to the field. A combination of soil coring with a hydraulic push press and manual core-break counting can directly phenotype root architecture traits of depth and distribution in the field through to grain development, but large teams of people are required and labour costs are high with this method. We developed a portable fluorescence imaging system (BlueBox) to automate root counting in soil cores with image analysis software directly in the field. The lighting system was optimized to produce high-contrast images of roots emerging from soil cores. The correlation of the measurements with the root length density of the soil cores exceeded the correlation achieved by human operator measurements (R (2)=0.68 versus 0.57, respectively). A BlueBox-equipped team processed 4.3 cores/hour/person, compared with 3.7 cores/hour/person for the manual method. The portable, automated in-field root architecture phenotyping system was 16% more labour efficient, 19% more accurate, and 12% cheaper than manual conventional coring, and presents an opportunity to directly phenotype root architecture in the field as part of pre-breeding programs. The platform has wide possibilities to capture more information about root health and other root traits in the field. PMID:26826219

  17. A portable fluorescence spectroscopy imaging system for automated root phenotyping in soil cores in the field

    PubMed Central

    Wasson, Anton; Bischof, Leanne; Zwart, Alec; Watt, Michelle

    2016-01-01

    Root architecture traits are a target for pre-breeders. Incorporation of root architecture traits into new cultivars requires phenotyping. It is attractive to rapidly and directly phenotype root architecture in the field, avoiding laboratory studies that may not translate to the field. A combination of soil coring with a hydraulic push press and manual core-break counting can directly phenotype root architecture traits of depth and distribution in the field through to grain development, but large teams of people are required and labour costs are high with this method. We developed a portable fluorescence imaging system (BlueBox) to automate root counting in soil cores with image analysis software directly in the field. The lighting system was optimized to produce high-contrast images of roots emerging from soil cores. The correlation of the measurements with the root length density of the soil cores exceeded the correlation achieved by human operator measurements (R 2=0.68 versus 0.57, respectively). A BlueBox-equipped team processed 4.3 cores/hour/person, compared with 3.7 cores/hour/person for the manual method. The portable, automated in-field root architecture phenotyping system was 16% more labour efficient, 19% more accurate, and 12% cheaper than manual conventional coring, and presents an opportunity to directly phenotype root architecture in the field as part of pre-breeding programs. The platform has wide possibilities to capture more information about root health and other root traits in the field. PMID:26826219

  18. Anaerobic biotransformation of trichlorofluoroethene in groundwater microcosms

    SciTech Connect

    Vancheeswaran, S.; Semprini, L. . Dept. of Civil, Construction, and Environmental Engineering); Hyman, M.R. . Dept. of Microbiology)

    1999-06-15

    The biological reduction of trichlorofluoroethene (TCFE) was investigated in anaerobic groundwater microcosms. TCFE was reductively dehalogenated by microorganisms to produce three dichlorofluoroethene isomers, with cis-1,2-dichlorofluoroethene (c-DCFE) being the main isomer formed. Further sequential biological transformation of these compounds to mono-chlorofluoroethene isomers was incomplete and occurred at much slower rates. The rates of TCFE reduction were compared to the rates of reduction of two common chlorinated solvents, perchloroethene (PCE) and trichloroethene (TCE), when present at similar concentrations. Aqueous concentrations ranged from 7.0 to 14.0 mg/L for TCFE and from 7.5 to 15.0 mg/L for PCE and TCE. Similar rates of PCE and TCE transformation relative to TCFE were observed in single-compound tests (PCE, TCE, and TCFE in separate microcosms) and when the contaminants were present together as mixtures in the microcosms. The close similarities between the time course and kinetics of TCFE degradation and the degradation of both PCE and TCE, when present at comparable initial concentrations, suggest that TCFE could potentially be used as a benign reactive tracer to measure in-situ rates of PCE and TCE transformation in contaminated environments.

  19. Cometabolic biodegradation of trichloroethylene in microcosms

    USGS Publications Warehouse

    Kane, Allen C.; Wilson, Timothy P.; Fischer, Jeffrey M.

    1997-01-01

    Laboratory microcosms were used to determine the concentrations of oxygen (O2) and methane (CH4) that optimize trichloroethylene (TCE) biodegradation in sediment and ground-water samples from a TCE-contaminated aquifer at Picatinny Arsenal, Morris County, New Jersey. The mechanism for degradation is the cometabolic activity of methanotrophic bacteria. The laboratory data will be used to support a field study designed to demonstrate the effectiveness of combining air sparging with cometabolic degradation of TCE for the purpose of aquifer remediation. Microcosms were constructed in autoclaved 250-mL (milliliter) amber glass bottles with valves for repeated headspace sampling. Equal volumes (25 mL) of sediment and ground water, collected from a depth of 40 feet, were added. TCE was added to attain initial aqueous concentrations equal to the field level of 1,400 mu g/L (micrograms per liter). Nine microcosms were constructed with initial headspace O2 concentrations of 5%, 10%, or 14% and CH4 concentrations of 0.5%, 3%, or 5%, with nitrogen making up the balance. Sterile controls, controls without CH4, and controls without sediment were also constructed. A 4-mL gas sample was removed periodically and TCE, O2 , CH4 , and carbon dioxide (CO2) concentrations were measured by using gas chromatography. As biodegradation proceeded, the decrease in O2, CH4 , and TCE concentrations and the production of CO2 were monitored. An initial acclimation period of at least 100 days was observed in those microcosms in which significant microbial activity occurred, as determined from decreases in O2 and CH4 concentrations and an increase in CO2 content. Degradation of TCE occurred with O2 concentrations of 2.7 to 8.7% and CH4 concentrations of 0.5 to 3.5%. Microcosms that initially contained 10% O2 and 3% CH4 showed the greatest microbial activity and the greatest amount of TCE degradation. The greatest rates of TCE degradation occurred when O2 and CH4 headspace concentrations reached

  20. Estimation of SX Farm Vadose Zone CS-137 Inventories from Geostatistical Analysis of Drywell and Soil Core Data

    SciTech Connect

    KNEPP, A.J.

    2000-06-02

    This report provides an estimation of the Cs-137 inventories in the soil under the SX Tank Farm based on measurements obtained from drywell and soil cores. The Cs-137 inventories are estimated separately for distinct volumes of soil associated etc.

  1. Arbuscular-mycorrhizal networks inhibit Eucalyptus tetrodonta seedlings in rain forest soil microcosms.

    PubMed

    Janos, David P; Scott, John; Aristizábal, Catalina; Bowman, David M J S

    2013-01-01

    Eucalyptus tetrodonta, a co-dominant tree species of tropical, northern Australian savannas, does not invade adjacent monsoon rain forest unless the forest is burnt intensely. Such facilitation by fire of seedling establishment is known as the "ashbed effect." Because the ashbed effect might involve disruption of common mycorrhizal networks, we hypothesized that in the absence of fire, intact rain forest arbuscular mycorrhizal (AM) networks inhibit E. tetrodonta seedlings. Although arbuscular mycorrhizas predominate in the rain forest, common tree species of the northern Australian savannas (including adult E. tetrodonta) host ectomycorrhizas. To test our hypothesis, we grew E. tetrodonta and Ceiba pentandra (an AM-responsive species used to confirm treatments) separately in microcosms of ambient or methyl-bromide fumigated rain forest soil with or without severing potential mycorrhizal fungus connections to an AM nurse plant, Litsea glutinosa. As expected, C. pentandra formed mycorrhizas in all treatments but had the most root colonization and grew fastest in ambient soil. E. tetrodonta seedlings also formed AM in all treatments, but severing hyphae in fumigated soil produced the least colonization and the best growth. Three of ten E. tetrodonta seedlings in ambient soil with intact network hyphae died. Because foliar chlorosis was symptomatic of iron deficiency, after 130 days we began to fertilize half the E. tetrodonta seedlings in ambient soil with an iron solution. Iron fertilization completely remedied chlorosis and stimulated leaf growth. Our microcosm results suggest that in intact rain forest, common AM networks mediate belowground competition and AM fungi may exacerbate iron deficiency, thereby enhancing resistance to E. tetrodonta invasion. Common AM networks-previously unrecognized as contributors to the ashbed effect-probably help to maintain the rain forest-savanna boundary. PMID:23460899

  2. Arbuscular-Mycorrhizal Networks Inhibit Eucalyptus tetrodonta Seedlings in Rain Forest Soil Microcosms

    PubMed Central

    Janos, David P.; Scott, John; Aristizábal, Catalina; Bowman, David M. J. S.

    2013-01-01

    Eucalyptus tetrodonta, a co-dominant tree species of tropical, northern Australian savannas, does not invade adjacent monsoon rain forest unless the forest is burnt intensely. Such facilitation by fire of seedling establishment is known as the "ashbed effect." Because the ashbed effect might involve disruption of common mycorrhizal networks, we hypothesized that in the absence of fire, intact rain forest arbuscular mycorrhizal (AM) networks inhibit E. tetrodonta seedlings. Although arbuscular mycorrhizas predominate in the rain forest, common tree species of the northern Australian savannas (including adult E. tetrodonta) host ectomycorrhizas. To test our hypothesis, we grew E. tetrodonta and Ceiba pentandra (an AM-responsive species used to confirm treatments) separately in microcosms of ambient or methyl-bromide fumigated rain forest soil with or without severing potential mycorrhizal fungus connections to an AM nurse plant, Litsea glutinosa. As expected, C. pentandra formed mycorrhizas in all treatments but had the most root colonization and grew fastest in ambient soil. E. tetrodonta seedlings also formed AM in all treatments, but severing hyphae in fumigated soil produced the least colonization and the best growth. Three of ten E. tetrodonta seedlings in ambient soil with intact network hyphae died. Because foliar chlorosis was symptomatic of iron deficiency, after 130 days we began to fertilize half the E. tetrodonta seedlings in ambient soil with an iron solution. Iron fertilization completely remedied chlorosis and stimulated leaf growth. Our microcosm results suggest that in intact rain forest, common AM networks mediate belowground competition and AM fungi may exacerbate iron deficiency, thereby enhancing resistance to E. tetrodonta invasion. Common AM networks–previously unrecognized as contributors to the ashbed effect–probably help to maintain the rain forest–savanna boundary. PMID:23460899

  3. (Photosynthesis in intact plants)

    SciTech Connect

    Not Available

    1990-01-01

    Progress in the two years since the last renewal application has been excellent. We have made substantial contributions on both main fronts of the projects, and are particularly happy with the progress of our research on intact plants. The approach of basing our field work on a sound foundation of laboratory studies has enabled is to use methods which provide unambiguous assays of well characterized reactions. We have also made excellent progress in several laboratory studies which will have direct applications in future field work, and have introduced to the laboratory a range of molecular genetics techniques which will allow us to explore new options in the attempt to understand function at the level of molecular structure.

  4. A Reproducible Oral Microcosm Biofilm Model for Testing Dental Materials

    PubMed Central

    Rudney, J.D.; Chen, R.; Lenton, P.; Li, J.; Li, Y.; Jones, R.S.; Reilly, C.; Fok, A.S.; Aparicio, C.

    2012-01-01

    Aims Most studies of biofilm effects on dental materials use single-species biofilms, or consortia. Microcosm biofilms grown directly from saliva or plaque are much more diverse, but difficult to characterize. We used the Human Oral Microbial Identification Microarray (HOMIM) to validate a reproducible oral microcosm model. Methods and Results Saliva and dental plaque were collected from adults and children. Hydroxyapatite and dental composite disks were inoculated with either saliva or plaque, and microcosm biofilms were grown in a CDC biofilm reactor. In later experiments, the reactor was pulsed with sucrose. DNA from inoculums and microcosms were analyzed by HOMIM for 272 species. Microcosms included about 60% of species from the original inoculum. Biofilms grown on hydroxyapatite and composites were extremely similar. Sucrose-pulsing decreased diversity and pH, but increased the abundance of Streptococcus and Veilonella. Biofilms from the same donor, grown at different times, clustered together. Conclusions This model produced reproducible microcosm biofilms that were representative of the oral microbiota. Sucrose induced changes associated with dental caries. Significance and Impact of the Study This is the first use of HOMIM to validate an oral microcosm model that can be used to study the effects of complex biofilms on dental materials. PMID:22925110

  5. Ecotoxicological assessment of biosolids by microcosms.

    PubMed

    Groth, Vitor Avelar; Carvalho-Pereira, Ticiana; da Silva, Eduardo Mendes; Niemeyer, Júlia Carina

    2016-10-01

    Biosolids have been applied as soil amendments to improve and maintain the soil fertility and faster plant growth. In spite of its beneficial use, the potential risks of land disposal should be analyzed, considering potential ecological receptors in soil and water. This work describes the use of an early warning laboratory microcosm system to evaluate the integrated ecotoxicological potential of two biosolids: BIO-1 and BIO-2 (18 and 28 months after landfarming, respectively), from an effluent treatment station in a petrochemical and industrial district. The endpoints related to habitat function were: a) germination, growth and biomass of Phaseolus vulgaris; b) survival, biomass and number of cocoons of Eisenia andrei (Oligochaeta) and; c) reproduction of Folsomia candida (Collembola). The retention function was evaluated by testing the leachates using the tropical cladoceran Latonopsis australis (Cladocera) in a 48-h acute toxicity test, and growth of the aquatic plant Lemna minor in a 7-d chronic test. Tropical artificial soil (TAS) and a natural soil (NS) from the region were used as control soils. Results showed no chronic toxicity of BIO-1 and BIO-2 to the soil organisms tested, but acute toxicity of BIO-1 in the leachate for 50% of L. australis, and chronic toxicity of both biosolid leachates to L. minor (inhibition of growth rate), indicating potential risks to aquatic ecosystems. The results confirmed the ability of this microcosm system as a rapid tool to assess biosolid toxicity over time and its potential for hazardous waste characterization in environmental risk assessment, in a screening phase. PMID:27448314

  6. Potassium leaching in undisturbed soil cores following surface applications of gypsum

    NASA Astrophysics Data System (ADS)

    Jalali, M.; Rowell, D. L.

    2009-03-01

    Displacement studies on leaching of potassium (K+) were conducted under unsaturated steady state flow conditions in nine undisturbed soil columns (15.5 cm in diameter and 25 cm long). Pulses of K+ applied to columns of undisturbed soil were leached with distilled water or calcium chloride (CaCl2) at a rate of 18 mm h-1. The movement of K+ in gypsum treated soil leached with distilled water was at a similar rate to that of the untreated soil leached with 15 mM CaCl2. The Ca2+ concentrations in the leachates were about 15 mM, the expected values for the dissolution of the gypsum. When applied K+ was displaced with the distilled water, K+ was retained in the top 10-12.5 cm depth of soil. In the undisturbed soil cores there is possibility of preferential flow and lack of K+ sorption. The application of gypsum and CaCl2 in the reclamation of sodic soils would be expected to leach K+ from soils. It can also be concluded that the use of sources of water for irrigation which have a high Ca2+ concentration can also lead to leaching of K+ from soil. Average effluent concentration of K+ during leaching period was 30.2 and 28.6 mg l-1 for the gypsum and CaCl2 treated soils, respectively. These concentrations are greater than the recommended guideline of the World Health Organisation (12 mg K+ l-1).

  7. Measurement of effective air diffusion coefficients for trichloroethene in undisturbed soil cores

    NASA Astrophysics Data System (ADS)

    Bartelt-Hunt, Shannon L.; Smith, James A.

    2002-06-01

    In this study, we measure effective diffusion coefficients for trichloroethene in undisturbed soil samples taken from Picatinny Arsenal, New Jersey. The measured effective diffusion coefficients ranged from 0.0053 to 0.0609 cm 2/s over a range of air-filled porosity of 0.23-0.49. The experimental data were compared to several previously published relations that predict diffusion coefficients as a function of air-filled porosity and porosity. A multiple linear regression analysis was developed to determine if a modification of the exponents in Millington's [Science 130 (1959) 100] relation would better fit the experimental data. The literature relations appeared to generally underpredict the effective diffusion coefficient for the soil cores studied in this work. Inclusion of a particle-size distribution parameter, d10, did not significantly improve the fit of the linear regression equation. The effective diffusion coefficient and porosity data were used to recalculate estimates of diffusive flux through the subsurface made in a previous study performed at the field site. It was determined that the method of calculation used in the previous study resulted in an underprediction of diffusive flux from the subsurface. We conclude that although Millington's [Science 130 (1959) 100] relation works well to predict effective diffusion coefficients in homogeneous soils with relatively uniform particle-size distributions, it may be inaccurate for many natural soils with heterogeneous structure and/or non-uniform particle-size distributions.

  8. Transport of bromide measured by soil coring, suction plates, and lysimeters under transient flow conditions.

    NASA Astrophysics Data System (ADS)

    Kasteel, R.; Pütz, Th.; Vereecken, H.

    2003-04-01

    Lysimeter studies are one step within the registration procedure of pesticides. Flow and transport in these free-draining lysimeters do not reflect the field situation mainly because of the occurence of a zone of local saturation at the lower boundary (seepage face). The objective of this study is to evaluate the impact of flow and transport behaviour of bromide detected with different measuring devices (lysimeters, suction plates, and soil coring) by comparing experimental results with numerical simulations in heterogeneous flow domains. We applied bromide as a small pulse to the bare soil surface (Orthic Luvisol) of the three devices and the displacement of bromide was regurlarly sampled for three years under natural wheather conditions. Based on the mean breakthrough curves we observe experimentally that lysimeters have a lower effective pore-water velocity and exhibit more solute spreading resulting in a larger dispersivity than the suction plates. This can be ascribed to the artefact of the lower boundary. We performed numerical transport simulations in 2-D heterogeneous flow fields (scaling approach) choosing appropriate boundary conditions for the various devices. The simulations allow to follow the temporal evolution of flow and transport processes in the various devices and to gain additional process understanding. We conclude that the model is essentially capable to reproduce the main experimental findings only if we account for the spatial correlation structure of the hydraulic properties, i.e. soil heterogeneity.

  9. The physics of intact capture

    NASA Technical Reports Server (NTRS)

    Tsou, Peter; Griffiths, D. J.; Albee, A. L.

    1994-01-01

    The ability to capture projectiles intact at hypervelocities in underdense media open a new area of study in physics. Underdense material behaves markedly different than solid, liquid, or gas upon hypervelocity impact. This new phenomenon enables applications in science that would either not be possible or would be very costly by other means. This phenomenon has been fully demonstrated in the laboratory and validated in space. Even more interesting is the fact that this hypervelocity intact capture was accomplished passively. A better understanding of the physics of intact capture will lead to improvements in intact capture. A collection of physical observations of this phenomenon is presented here.

  10. Atrazine soil core residue analysis from an agricultural field 21 years after its ban.

    PubMed

    Vonberg, David; Hofmann, Diana; Vanderborght, Jan; Lelickens, Anna; Köppchen, Stephan; Pütz, Thomas; Burauel, Peter; Vereecken, Harry

    2014-07-01

    Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) groundwater monitoring in the Zwischenscholle aquifer in western Germany revealed concentrations exceeding the threshold value of 0.1 μg L and increasing concentration trends even 20 yr after its ban. Accordingly, the hypothesis was raised that a continued release of bound atrazine residues from the soil into the Zwischenscholle aquifer in combination with the low atrazine degradation in groundwater contributes to elevated atrazine in groundwater. Three soil cores reaching down to the groundwater table were taken from an agricultural field where atrazine had been applied before its ban in 1991. Atrazine residues were extracted from eight soil layers down to 300 cm using accelerated solvent extraction and analyzed using liquid chromatography-tandem mass spectrometry. Extracted atrazine concentrations ranged between 0.2 and 0.01 μg kg for topsoil and subsoil, respectively. The extracted mass from the soil profiles represented 0.07% of the applied mass, with 0.01% remaining in the top layer. A complete and instantaneous remobilization of atrazine residues and vertical mixing with the groundwater body below would lead to atrazine groundwater concentrations of 0.068 μg L. Considering the area where atrazine was applied in the region and assuming instantaneous lateral mixing in the Zwischenscholle aquifer would result in a mean groundwater concentration of 0.002 μg L. A conservative estimation suggests an atrazine half-life value of about 2 yr for the soil zone, which significantly exceeds highest atrazine half-lives found in the literature (433 d for subsurface soils). The long-term environmental behavior of atrazine and its metabolites thus needs to be reconsidered. PMID:25603092

  11. Effect of organic loading on nitrification and denitrification in a marine sediment microcosm

    USGS Publications Warehouse

    Caffrey, J.M.; Sloth, N.P.; Kaspar, H.F.; Blackburn, T.H.

    1993-01-01

    The effects of organic additions on nitrification and denitrification were examined in sediment microcosms. The organic material, heat killed yeast, had a C/N ratio of 7.5 and was added to sieved, homogenized sediments. Four treatments were compared: no addition (control, 30 g dry weight (dw) m-2 mixed throughout the 10 cm sediment column (30 M), 100 g dw m-2 mixed throughout sediments (100M), and 100 g dw m-2 mixed into top 1 cm (100S). After the microcosms had been established for 7-11 days, depth of O2 penetration, sediment-water fluxes and nitrification rates were measured. Nitrification rates were measured using three different techniques: N-serve and acetylene inhibition in intact cores, and nitrification potentials in slurries. Increased organic additions decreased O2 penetration from 2.7 to 0.2 mm while increasing both O2 consumption, from 30 to 70 mmol O2 m-2 d-1, and NO3- flux into sediments. Nitrification rates in intact cores were similar for the two methods. Highest rates occurred in the 30 M treatment, while the lowest rate was measured in the 100S treatment. Total denitrification rates (estimated from nitrification and nitrate fluxes) increased with increased organic addition, because of the high concentrations of NO3- (40 ??M) in the overlying water. The ratio of nitrification: denitrification was used as an indication of the importance of nitrification as the NO3- supply for denitrification. This ratio decreased from 1.55 to 0.05 with increased organic addition.

  12. Space research with intact organisms

    NASA Technical Reports Server (NTRS)

    Phillips, Robert W.; Haddy, Francis J.

    1992-01-01

    Effects of space exposure on intact organisms are briefly reviewed, and examples of future experiments that might provide new information on the role of gravity in the evolution of life are suggested. It is noted that long term experiments with intact plant and animals for studying gravitational thresholds will provide important new insights.

  13. Effect of vegetation removal and water table drawdown on the non-methane biogenic volatile organic compound emissions in boreal peatland microcosms

    NASA Astrophysics Data System (ADS)

    Faubert, Patrick; Tiiva, Päivi; Rinnan, Åsmund; Räty, Sanna; Holopainen, Jarmo K.; Holopainen, Toini; Rinnan, Riikka

    2010-11-01

    Biogenic volatile organic compound (BVOC) emissions are important in the global atmospheric chemistry and their feedbacks to global warming are uncertain. Global warming is expected to trigger vegetation changes and water table drawdown in boreal peatlands, such changes have only been investigated on isoprene emission but never on other BVOCs. We aimed at distinguishing the BVOCs released from vascular plants, mosses and peat in hummocks (dry microsites) and hollows (wet microsites) of boreal peatland microcosms maintained in growth chambers. We also assessed the effect of water table drawdown (-20 cm) on the BVOC emissions in hollow microcosms. BVOC emissions were measured from peat samples underneath the moss surface after the 7-week-long experiment to investigate whether the potential effects of vegetation and water table drawdown were shown. BVOCs were sampled using a conventional chamber method, collected on adsorbent and analyzed with GC-MS. In hummock microcosms, vascular plants increased the monoterpene emissions compared with the treatment where all above-ground vegetation was removed while no effect was detected on the sesquiterpenes, other reactive VOCs (ORVOCs) and other VOCs. Peat layer from underneath the surface with intact vegetation had the highest sesquiterpene emissions. In hollow microcosms, intact vegetation had the highest sesquiterpene emissions. Water table drawdown decreased monoterpene and other VOC emissions. Specific compounds could be closely associated to the natural/lowered water tables. Peat layer from underneath the surface of hollows with intact vegetation had the highest emissions of monoterpenes, sesquiterpenes and ORVOCs whereas water table drawdown decreased those emissions. The results suggest that global warming would change the BVOC emission mixtures from boreal peatlands following changes in vegetation composition and water table drawdown.

  14. MICROCOSM METHOD TO ASSESS SURVIVAL OF RECOMBINANT BACTERIA ASSOCIATED WITH PLANTS AND HERBIVOROUS INSECTS (JOURNAL VERSION)

    EPA Science Inventory

    A microcosm method was developed to investigate survival and fate of genetically engineered bacteria associated with plant surfaces and a plant-feeding insect, the variegated cutworm, Peridroma saucia. Larvae on radish plants in microcosms were sprayed with nonrecombinant Pseudom...

  15. Intact capture of hypervelocity particles

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    1986-01-01

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  16. Intact capture of hypervelocity particles

    NASA Astrophysics Data System (ADS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  17. Influence of water table on carbon dioxide, carbon monoxide, and methane fluxes from taiga bog microcosms

    SciTech Connect

    Funk, D.W.; Pullmann, E.R.; Peterson, K.M.

    1994-09-01

    Hydrological changes, particularly alterations in water table level, may largely overshadow the more direct effects of global temperature increase upon carbon cycling in arctic and subarctic wetlands. Frozen cores (n=40) of intact soils and vegetation were collected from a bog near Fairbanks, Alaska, and fluxes of CO{sub 2}, CH{sub 4}, and Co in response to water table variation were studied under controlled conditions in the Duke University phytotron. Core microcosms thawed to a 20-cm depth over 30 days under a 20 hour photoperiod with a day/night temperature regime of 20/10{degrees}C. After 30 days the water table in 20 microcosms was decreased from the soil surface to -15 cm and maintained at the soil surface in 20 control cores. Outward fluxes of CO{sub 2} (9-16 g m{sup -2}d{sup -1}) and CO (3-4 mg m{sup -2}d{sup -1}) were greatest during early thaw and decreased to near zero for both gases before the water table treatment started. Lower water table tripled CO{sub 2} flux to the atmosphere when compared with control cores. Carbon monoxide was emitted at low rates from high water table cores and consumed by low water table cores. Methane fluxes were low (<1 mg m{sup -2}d{sup -1}) in all cores during thaw. High water table cores increased CH{sub 4} flux to 8-9 mg m{sup -2}d{sup -1} over 70 days and remained high relative to the low water table cores (<0.74 mg m{sup -2}d{sup -1}). Although drying of wetland taiga soils may decrease CH{sub 4} emissions to the atmosphere, the associated increase in CO{sub 2} due to aerobic respiration will likely increase the global warming potential of gas emissions from these soils. 43 refs., 4 figs.

  18. Intact capture of cosmic dust

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1991-01-01

    The focus of this development effort is to capture dust particles at hypervelocities intact and unmelted in order to preserve volatile organics. At the same time, the capture process must minimize any organic elemental or compound contamination to prevent any compromise of exobiological analyses. Inorganic silicate aerogel has been developed as a successful capture medium to satisfy both requirements of intact capture and minimal organic contamination. Up to 6 km/s, silicate projectiles from a few microns up to 100 microns have been captured intact without any melting and with minimal loss of mass. Carbon in silicate aerogel can be reduced to less than 1 part in 1000 and hydrogen 3 parts in 1000 when baked in air. Under controlled inert gas environments, additional hydrocarbon reduction can be achieved.

  19. IMPACT OF UV-B RADIATION UPON ESTUARINE MICROCOSMS

    EPA Science Inventory

    Twelve flow-through estuarine microcosms were exposed daily to four different levels of UV-B radiation. In addition to a natural level of visible solar radiation. The parameters studied over a four week period were phytoplankton community composition, plankton biomass (ash-free d...

  20. Comparison of laboratory batch and flow-through microcosm bioassays.

    PubMed

    Clément, Bernard J P; Delhaye, Hélène L; Triffault-Bouchet, Gaëlle G

    2014-10-01

    Since 1997, we have been developing a protocol for ecotoxicological bioassays in 2-L laboratory microcosms and have applied it to the study of various pollutants and ecotoxicological risk assessment scenarios in the area of urban facilities and transport infrastructures. The effects on five different organisms (micro-algae, duckweeds, daphnids, amphipods, chironomids) are assessed using biological responses such as growth, emergence (chironomids), reproduction (daphnids) and survival, with a duration of exposure of 3 weeks. This bioassay has mainly been used as a batch bioassay, i.e., the water was not renewed during the test. A flow-through microcosm bioassay has been developed recently, with the assumption that conditions for the biota should be improved, variability reduced, and the range of exposure patterns enlarged (e.g., the possibility of maintaining constant exposure in the water column). This paper compares the results obtained in batch and flow-through microcosm bioassays, using cadmium as a model toxicant. As expected, the stabilization of physico-chemical parameters, increased organism fitness and reduced variability were observed in the flow-through microcosm bioassay. PMID:25086825

  1. Figs and fig wasps: evolution in a microcosm.

    PubMed

    Cook, J M; Lopez-Vaamonde, C

    2001-06-01

    Fig wasps are tiny insects that both pollinate and feed upon fig plants. Each species requires the other in order to complete its reproductive cycle. The interaction centres on the unique structure of syconium (fig inflorescence), which provides an intriguing and convenient microcosm for studying the action of both natural and sexual selection. PMID:11399840

  2. CHARACTERIZING THE MICROBIAL COMMUNITY IN SABRE MICROCOSM STUDIES (ABSTRACT ONLY)

    EPA Science Inventory

    The SABRE (Source Area BioREmediation) project will evaluate accelerated anaerobic bioremediation of chlorinated solvents in areas of high concentration, such as DNAPL source areas. In preparation for a field scale pilot test, laboratory microcosm and column studies were conducte...

  3. FATE OF SELECTED HERBICIDES IN A TERRESTRIAL LABORATORY MICROCOSM

    EPA Science Inventory

    The transport and metabolism of 14C-labeled herbicides (simazine, bromacil, trifluralin, and 2,4,5-T) applied as a foliar spray (0.28 kg/ha) was examined in a terrestrial microcosm chamber (TMC). These chemicals were compared to a reference compound, the insecticide dieldrin. The...

  4. METRICS OF PERFORMANCE FOR THE SABRE MICROCOSM STUDY (ABSTRACT ONLY)

    EPA Science Inventory

    The SABRE (Source Area BioREmediation) project will evaluate accelerated anaerobic bioremediation of chlorinated solvents in areas of high concentration, such as DNAPL source areas. In preparation for a field scale pilot test, a laboratory microcosm study was conducted to provide...

  5. TROPHIC STRUCTURE MODIFICATIONS BY PLANKTIVOROUS FISH IN AQUATIC MICROCOSMS

    EPA Science Inventory

    Two of 4 replicate 700-liter aquatic microcosms each were stocked with 2 mosquito fish (Gambusia affinis). The dominant zooplankter shifted from the large cladoceran Simocephalus vetulus to the smaller Alona guttata. The subsequent release of grazing pressure resulted in a rise i...

  6. Degradation and bioavailability of sulfamethazine in pond water microcosms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antibiotic sulfamethazine can be transported from manured fields to farm ponds. We investigated the degradation and fate of sulfamethazine in small pond water microcosms. 14C-phenyl-sulfamethazine was added to the pond water column in a swine manure slurry or in water. Residual concentrations in...

  7. TRANSFORMATION OF CHIRAL POLLUTANTS IN SOIL AND SEDIMENT MICROCOSMS

    EPA Science Inventory

    The transformation rates and enantiomeric ratios of several chiral pollutants were determined in laboratory microcosms (25oC). Aerobic and anaerobic agricultural soil slurries were separately dosed with the following chiral pesticides: o,p'-DDT, o,p'-methoxychlor, cis-chlordane, ...

  8. FATE AND IMPACT OF WOOD PRESERVATIVES IN A TERRESTRIAL MICROCOSM

    EPA Science Inventory

    The transport and effects of 14C-labeled wood preservatives (creosote with labeled phenanthrene or acenaphthene, pentachlorophenol, and bis(tri-n-butyltin)oxide) impregnated in wood posts were examined in a terrestrial microcosm chamber (TMC-II) in comparison to a reference compo...

  9. Recent advances in the use of estuarine meiobenthos to assess contaminated sediment effects in multi-species whole sediment microcosms

    SciTech Connect

    Chandler, G.T.; Coull, B.C.; Schizas, N.V.; Donelan, T.L.

    1995-12-31

    Many marine meiobenthic taxa (i.e. invertebrates passing a 1-mm sieve but retaining on a 0.063 mm sieve) are ideal for ``whole-sediment`` and porewater bioassay of sedimented pollutants. Annual production of meiobenthos is 5--10 times that of the more commonly studied macrobenthos, and > 95% of all meiobenthos live in the oxic zone of muddy sediments at densities of 4--12 million per M{sup 2}. Most spend their entire lifecycles, burrowing freely and feeding on/within the sediment:porewater matrix, many taxa undergo 10--14 generations per year, most larval/juvenile stages are benthic, and many have easily quantifiable reproductive output. Furthermore, many meiobenthic taxa can be cultured indefinitely over multiple life-cycles within simple sediment microcosms consisting of sealed whole-sediment cores collected intact from intertidal mudflats. The authors describe several recent technical developments exploiting meiofaunal sediment culture for rapid contaminated sediment bioassays of toxicant effects on survival, reproduction and population growth of meiobenthic taxa in whole-sediment microcosms. Currently meiobenthic copepods, nematodes, foraminifers and polychaetes are being continuously cultured to study these parameters under exposure to model sediment-associated toxicants (e.g. cadmium). Bioassays are run for 21-d under flowing seawater. With this approach, fertile benthic copepods (e.g. Amphiascus tenuiremis) can be added to core microcosms to assess survival and growth of a fixed population cohort. All other meiobenthic taxa are enumerated relative to controls and evaluated for toxicant effects on higher order community-level endpoints. This approach exploits meiobenthos` high abundance and rapid reproductive rates to yield on a micro scale better endpoints than much larger sediment mesocosms targeted at macrofaunal endpoints.

  10. Metal binding in soil cores and sediments in the vicinity of a dammed agricultural and industrial watershed.

    PubMed

    Kanbar, Hussein Jaafar; Hanna, Nour; El Samrani, Antoine G; Kazpard, Véronique; Kobaissi, Ahmad; Harb, Nafez; Amacha, Nabil

    2014-12-01

    The environment is witnessing a downgrade caused by the amelioration of the industrial and agricultural sectors, namely, soil and sediment compartments. For those reasons, a comparative study was done between soil cores and sediments taken from two locations in the Qaraaoun reservoir, Lebanon. The soil cores were partitioned into several layers. Each layer was analyzed for several physicochemical parameters, such as functional groups, particle size distribution, ζ-potential, texture, pH, electric conductivity, total dissolved solids, organic matter, cation exchange capacity, active and total calcareous, available sodium and potassium, and metal content (cadmium, copper, and lead). The metal content of each site was linked to soil composition and characteristics. The two sites showed distinguishable characteristics for features such as organic matter, pH, mineral fraction, calcareous, and metal content. The samples taken toward the south site (Q1), though contain lower organic matter than the other but are more calcareous, showed higher metal content in comparison to the other site (Q2) (average metal content of Q1 > Q2; for Cd 3.8 > 1.8 mg/kg, Cu 28.6 > 21.9 mg/kg, Pb 26.7 > 19 mg/kg). However, the metal content in this study did not correlate as much to the organic matter; rather, it was influenced by the location of the samples with respect to the dam, the reservoir's hydrodynamics, the calcareous nature of the soil, and the variation of the industrial and agricultural influence on each site. PMID:25228528

  11. Spatial Changes in the Bacterial Community Structure along a Vertical Oxygen Gradient in Flooded Paddy Soil Cores

    PubMed Central

    Lüdemann, Heiner; Arth, Inko; Liesack, Werner

    2000-01-01

    Molecular ecology techniques were applied to assess changes in the bacterial community structure along a vertical oxygen gradient in flooded paddy soil cores. Microsensor measurements showed that oxygen was depleted from 140 μM at the floodwater/soil interface to nondetectable amounts at a depth of approximately 2.0 mm and below. Bacterial 16S rRNA gene (rDNA)-based community fingerprint patterns were obtained from 200-μm-thick soil slices of both the oxic and anoxic zones by using the T-RFLP (terminal restriction fragment length polymorphism) technique. The fingerprints revealed a tremendous shift in the community patterns in correlation to the oxygen depletion measured with depth. 16S rDNA clone sequences recovered from the oxic or anoxic zone directly corresponded to those terminal restriction fragments which were highly characteristic of the respective zone. Comparative sequence analysis of these clones identified members of the α and β subclasses of Proteobacteria as the abundant populations in the oxic zone. In contrast, members of clostridial cluster I were determined to be the predominant bacterial group in the oxygen-depleted soil. The extraction of total RNA followed by reverse transcription-PCR of the bacterial 16S rRNA and T-RFLP analysis resulted for both oxic and anoxic zones of flooded soil cores in community fingerprint patterns similar to those obtained by the rDNA-based analysis. This finding suggests that the microbial groups detected on the rDNA level are the metabolically active populations within the oxic and anoxic soil slices examined. PMID:10653747

  12. Soil coring at multiple field environments can directly quantify variation in deep root traits to select wheat genotypes for breeding.

    PubMed

    Wasson, A P; Rebetzke, G J; Kirkegaard, J A; Christopher, J; Richards, R A; Watt, M

    2014-11-01

    We aim to incorporate deep root traits into future wheat varieties to increase access to stored soil water during grain development, which is twice as valuable for yield as water captured at younger stages. Most root phenotyping efforts have been indirect studies in the laboratory, at young plant stages, or using indirect shoot measures. Here, soil coring to 2 m depth was used across three field environments to directly phenotype deep root traits on grain development (depth, descent rate, density, length, and distribution). Shoot phenotypes at coring included canopy temperature depression, chlorophyll reflectance, and green leaf scoring, with developmental stage, biomass, and yield. Current varieties, and genotypes with breeding histories and plant architectures expected to promote deep roots, were used to maximize identification of variation due to genetics. Variation was observed for deep root traits (e.g. 111.4-178.5cm (60%) for depth; 0.09-0.22cm/°C day (144%) for descent rate) using soil coring in the field environments. There was significant variation for root traits between sites, and variation in the relative performance of genotypes between sites. However, genotypes were identified that performed consistently well or poorly at both sites. Furthermore, high-performing genotypes were statistically superior in root traits than low-performing genotypes or commercial varieties. There was a weak but significant negative correlation between green leaf score (-0.5), CTD (0.45), and rooting depth and a positive correlation for chlorophyll reflectance (0.32). Shoot phenotypes did not predict other root traits. This study suggests that field coring can directly identify variation in deep root traits to speed up selection of genotypes for breeding programmes. PMID:24963000

  13. Bioaccumulation and toxicity of copper in outdoor freshwater microcosms.

    PubMed

    Hoang, Tham C; Pryor, Rachel L; Rand, Gary M; Frakes, Robert A

    2011-05-01

    This study characterizes the effects of copper (Cu) on Florida apple snails (Pomacea paludosa) and mosquito fish (Gambusia affinis) using a replicated outdoor microcosm design. Soils used in this study were collected from two Cu-enriched citrus agricultural sites in South Florida (Agler property (AGLR) in St. Lucie County and Sunrise Boys property (SRB) in Palm Beach County) and a reference site (Equus property) in St. Lucie County. The study included a 5-week aging phase, an 11 month exposure phase, and a 3 month post-treatment (exposure) phase. The aging phase was initiated by flooding agricultural soils with rainwater in 4 m(3) fiberglass microcosm tanks. Introducing juvenile apple snails (≤7 d old) and mosquito fish (2-3 cm) into the microcosm tanks initiated the exposure phase. Survival, growth, and reproduction of apple snails and fish, and Cu uptake in apple snails, fish, and periphyton were determined in this study. Water chemistry (e.g., dissolved Cu concentration, dissolved organic carbon and dissolved oxygen concentrations, pH, hardness, alkalinity, etc.) was measured daily or weekly during the study. Initial soil Cu concentrations in Equus, SRB, and AGLR microcosms were 7, 55, and 99 mg/kg dw, respectively. Dissolved Cu concentrations in Equus, SRB and AGLR microcosms at the beginning of the study were 3, 82, and 43 μg/L, respectively and decreased to low saturation levels of about ≤9 μg/L Cu after the first 3 months of the study. The decrease of dissolved Cu concentrations was likely due to the dilution of rainwater. Snail and fish mortality appeared to be higher in SRB microcosms than in Equus and AGLR microcosms. There was no significant difference in growth of the snails between treatments. Snail growth data followed the von Bertalanffy Model. The maximum shell length, shell height, and shell width of the snails calculated by the von Bertalanffy Model (L(∞)) were 2.76, 2.05, and 2.18 cm, respectively. The maximum wet weight was 9.38 g

  14. Monitoring Intact Viruses Using Aptamers.

    PubMed

    Kumar, Penmetcha K R

    2016-01-01

    Viral diagnosis and surveillance are necessary steps in containing the spread of viral diseases, and they help in the deployment of appropriate therapeutic interventions. In the past, the commonly employed viral detection methods were either cell-culture or molecule-level assays. Most of these assays are laborious and expensive, require special facilities, and provide a slow diagnosis. To circumvent these limitations, biosensor-based approaches are becoming attractive, especially after the successful commercialization of glucose and other biosensors. In the present article, I have reviewed the current progress using the biosensor approach for detecting intact viruses. At the time of writing this review, three types of bioreceptor surfaces (antibody-, glycan-, and aptamer-based) have been explored on different sensing platforms for detecting intact viruses. Among these bioreceptors, aptamer-based sensors have been increasingly explored for detecting intact viruses using surface plasmon resonance (SPR) and other platforms. Special emphasis is placed on the aptamer-based SPR platform in the present review. PMID:27527230

  15. Language and Williams syndrome: how intact is "intact"?

    PubMed

    Karmiloff-Smith, A; Grant, J; Berthoud, I; Davies, M; Howlin, P; Udwin, O

    1997-04-01

    It has been claimed that Williams syndrome (WS), a rare neurodevelopmental disorder, is characterized by serious cognitive deficits alongside intact language. The syndrome is often used as a prime example of the modularity of an innate faculty for morphosyntactic rules. We challenge this claim and hypothesize that morphosyntax, although surprisingly good given WS level of mental retardation, is by no means intact. We make an initial test of this hypothesis through an analysis of the receptive language of a group of English-speaking WS individuals on a standardized morphosyntactic test. We then present an experimental study of expressive language that examines grammatical gender assignment in French-speaking WS patients. Despite a Verbal Mental Age selected to be higher than the chronological age of the young control group, these people with WS continue even in adulthood to show clear-cut deficits in their production of an aspect of morphosyntax that normal children acquire effortlessly very early. The results of the 2 studies, one focusing on receptive language and the other on expressive language, challenge the notion that comprehension and use of morphosyntactic rules in WS individuals are intact. The Within-domain dissociations regarding the use of grammatical gender assignment across several sentence clements and their difficulties in understanding embedded sentences-two quintessentially linguistic skills-suggest that we must rethink the notion of spared, modular, language capacities in Williams syndrome. We conclude that WS language follows a different path to normal acquisition and may turn out to be more like second language learning. PMID:9180000

  16. Modelling of Genetically Engineered Microorganisms Introduction in Closed Artificial Microcosms

    NASA Astrophysics Data System (ADS)

    Pechurkin, N. S.; Brilkov, A. V.; Ganusov, V. V.; Kargatova, T. V.; Maksimova, E. E.; Popova, L. Yu.

    1999-01-01

    The possibility of introducing genetically engineered microorganisms (GEM) into simple biotic cycles of laboratory water microcosms was investigated. The survival of the recombinant strain Escherichia coli Z905 (Apr, Lux+) in microcosms depends on the type of model ecosystems. During the absence of algae blooming in the model ecosystem, the part of plasmid-containing cells E. coli decreased fast, and the structure of the plasmid was also modified. In conditions of algae blooming (Ankistrodesmus sp.) an almost total maintenance of plasmid-containing cells was observed in E.coli population. A mathematics model of GEM's behavior in water ecosystems with different level of complexity has been formulated. Mechanisms causing the difference in luminescent exhibition of different species are discussed, and attempts are made to forecast the GEM's behavior in water ecosystems.

  17. Morphological Alteration and Survival of Burkholderia pseudomallei in Soil Microcosms.

    PubMed

    Kamjumphol, Watcharaporn; Chareonsudjai, Pisit; Taweechaisupapong, Suwimol; Chareonsudjai, Sorujsiri

    2015-11-01

    The resilience of Burkholderia pseudomallei, the causative agent of melioidosis, was evaluated in control soil microcosms and in soil microcosms containing NaCl or FeSO4 at 30°C. Iron (Fe(II)) promoted the growth of B. pseudomallei during the 30-day observation, contrary to the presence of 1.5% and 3% NaCl. Scanning electron micrographs of B. pseudomallei in soil revealed their morphological alteration from rod to coccoid and the formation of microcolonies. The smallest B. pseudomallei cells were found in soil with 100 μM FeSO4 compared with in the control soil or soil with 0.6% NaCl (P < 0.05). The colony count on Ashdown's agar and bacterial viability assay using the LIVE/DEAD(®) BacLight(™) stain combined with flow cytometry showed that B. pseudomallei remained culturable and viable in the control soil microcosms for at least 120 days. In contrast, soil with 1.5% NaCl affected their culturability at day 90 and their viability at day 120. Our results suggested that a low salinity and iron may influence the survival of B. pseudomallei and its ability to change from a rod-like to coccoid form. The morphological changes of B. pseudomallei cells may be advantageous for their persistence in the environment and may increase the risk of their transmission to humans. PMID:26324731

  18. Intact capture of hypervelocity projectiles.

    PubMed

    Tsou, P

    1990-01-01

    The ability to capture projectiles intact at hypervelocities opens new applications in science and technology that would either not be possible or would be very costly by other means. This capability has been demonstrated in the laboratory for aluminum projectiles of 1.6 mm diameter, captured at 6 km/s, in one unmelted piece, and retaining up to 95% of the original mass. Furthermore, capture was accomplished passively using microcellular underdense polymer foam. Another advantage of capturing projectiles in an underdense medium is the ability of such a medium to preserve a record of the projectile's original velocity components of speed and direction. A survey of these experimental results is described in terms of a dozen parameters which characterize the amount of capture and the effect on the projectile due to different capture media. PMID:11538362

  19. Biotransformations of Aroclor 1242 in Hudson River test tube microcosms

    SciTech Connect

    Fish, K.M.; Principe, J.M.

    1994-12-01

    Polychlorinated biphenyls (PCBs) are relatively unreactive and hydrophobic, are widely used commercially, and have accumulated in soils, sediments, and biota. The researchers partially simulated environmental conditions in the laboratory to examine the fate of Aroclor 1242 in the Upper Hudson River. The test tube microcosms developed both aerobic and anaerobic compartments. This paper reports on the patterns and rates of anaerobic and aerobic PCB transformations for a single set of conditions in static, unamended microosms to model the environmental fate of Aroclor 1242 in river sediments. 23 refs., 5 figs.

  20. EFFECTS OF SEDIMENT TYPE ON BENTHIC MACROINFAUNAL COLONIZATION OF LABORATORY MICROCOSMS

    EPA Science Inventory

    We tested the effects of four different sediment types on macroinfaunal colonization and community development in our laboratory flow-thru microcosm system (all microcosms were 20 cm side-1 and sediment depth was 5 cm) over a period of 41 days. Sediments included Santa Rosa Islan...

  1. ASSESSMENT OF THE PRECISION AND ACCURACY OF SAM AND MFC MICROCOSMS EXPOSED TO TOXICANTS

    EPA Science Inventory

    The results of 30 mixed flank culture (MFC) and four standardized aquatic microcosm (SAM) microcosm experiments were used to describe the precision and accuracy of these two protocols. oefficients of variation (CV) for chemicals measurements (DO,pH) were generally less than 7%, f...

  2. SOME EFFECTS OF CADMIUM ON CONIFEROUS FOREST SOIL AND LITTER MICROCOSMS

    EPA Science Inventory

    Description and criticism is given of a preliminary design and use of a soil/litter microcosm in which oxygen, temperature, and humidity are kept constant, and oxygen generation and carbon dioxide and heat evolution rates are monitored. Using four microcosms, one acting as a dead...

  3. FATE OF FENTHION IN SALT-MARSH ENVIRONMENTS: II. TRANSPORT AND BIODEGRADATION IN MICROCOSMS

    EPA Science Inventory

    The fate of fenthion was examined in microcosms to define the possible interaction between sediment and biodegradation in the field. athematical model was also calibrated to calculate the distribution of fenithion in microcosms. ntact sediment cores, both with and without Juncus ...

  4. Isomer-specific investigation of PCDD/F mobility and other fate processes in deep soil cores.

    PubMed

    Grant, Sharon; Stevenson, Gavin; Malcolm, Don; Zennegg, Markus; Gaus, Caroline

    2015-10-01

    Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are highly hydrophobic compounds with low migration potential in soil-water. Nevertheless, they have been occasionally reported in subsurface soils hypothesised as the result of facilitated transport processes with colloids or surfactants, or yet unidentified in-situ formation processes. To date, however, the prevalence of deep soil contamination, involved processes and their kinetics remain poorly understood. This study investigated PCDD/F concentrations and isomer profiles through deep soil cores (to 20 m) from agricultural, industrial and urban sites in Queensland, Australia. Based on isomer profiles, a unique source common to all core soils (regardless of depth) was identified, dominated by octachlorodibenzo-p-dioxin (OCDD). The source was consistent with contamination resulting from pesticide impurities. Elevated PCDD concentrations (μg/kg range) to depths up to ∼4-17 m and a continuous increase of peri-chlorinated (1,4,6,9-substituted) isomers through the cores suggested that vertical transport and lateral dechlorination were key post-depositional processes at these sites. The mobility of PCDDs in the present study is far greater than previously reported in soils in general. High estimated mass transport rates for OCDD in four agricultural cores (3.0-6.2% year(-1)) likely reflect significant levels of facilitating species, including surfactants, and intensive rainfall at these sites. The implications of such extensive subsurface transport of PCDD/Fs for groundwater contamination and load estimates may be significant. If the cores of the present study are assumed representative of the region, a total PCDD/F load in the order of 800 tonnes (1.6 tonnes TEQ) could be present in subsurface Queensland coastal soils. PMID:26025295

  5. Extracellular proteases are released by ciliates in defined seawater microcosms.

    PubMed

    Thao, Ngo Vy; Nozawa, Akino; Obayashi, Yumiko; Kitamura, Shin-Ichi; Yokokawa, Taichi; Suzuki, Satoru

    2015-08-01

    The biodegradation of proteins in seawater requires various proteases which are commonly thought to be mainly derived from heterotrophic bacteria. We, however, found that protists showed a high protease activity and continuously produced trypsin-type enzymes. The free-living marine heterotrophic ciliate Paranophrys marina together with an associated bacterium was isolated and used for microcosm incubation with different concentrations of killed bacteria as food for 10 days. The results showed that the co-existence of the ciliate with its associated bacterium produced a significant protease activity in both cell-associated and cell-free fractions while that in the associated bacterium only microcosm was negligible. The protease profiles are different between cell-associated and cell-free fractions, and a trypsin-type enzyme hydrolyzing Boc-Val-Leu-Lys-MCA was detected throughout the period in the presence of ciliates. This suggests that ciliates release proteases into the surrounding environment which could play a role in protein digestion outside cells. It has been previously suggested that bacteria are the major transformers in seawater. We here present additional data which indicates that protists, or at least ciliates with their specific enzymes, are a potential player in organic matter degradation in water columns. PMID:26115436

  6. Fate of neptunium in an anaerobic, methanogenic microcosm.

    SciTech Connect

    Banaszak, J. E.

    1998-12-21

    Neptunium is found predominantly as Np(IV) in reducing environments, but Np(V) in aerobic environments. However, currently it is not known how the interplay between biotic and abiotic processes affects Np redox speciation in the environment. In order to evaluate the effect of anaerobic microbial activity on the fate of Np in natural systems, Np(V) was added to a microcosminoculated with anaerobic sediments from a metal-contaminated fresh water lake. The consortium included metal-reducing, sulfate-reducing, and methanogenic microorganisms, and acetate was supplied as the only exogenous substrate. Addition of more than 10{sup {minus}5} M Np did not inhibit methane production. Total Np volubility in the active microcosm, as well as in sterilized control samples, decreased by nearly two orders of magnitude. A combination of analytical techniques, including VIS-NIR absorption spectroscopy and XANES, identified Np(IV) as the oxidation state associated with the sediments. The similar results from the active microcosm and the abiotic controls suggest that microbian y produced Mn(II/HI) and Fe(II) may serve as electron donors for Np reduction.

  7. Azolla-anabaena-bacteria system as a natural microcosm

    NASA Astrophysics Data System (ADS)

    Carrapico, Francisco J.

    2002-02-01

    Azolla is an aquatic fern that contains a permanent endosymbiotic prokaryotic community (cyanobacteria and bacteria) inside of the cavity in the leaf dorsal lobe of the pteridophyte. This is a unique situation and can be seen as a microcosm inside of an organism and also can be considered a good example of a living model for biological and environmental studies. These symbionts are specific of this symbiosis and lives immobilized in a mucilaginous fibrillar network, which fills part of the cavity. The symbionts works as immobilized organisms in a natural system that can be used as a model for biotechnological research and in biologically based life support systems. The nature and the complexity of this system is simultaneously a reference and a challenge for the research in the communication between the two levels of nature organization (microcosm and mesocosm), and can also be used as a reference for the design of new environmental engineered symbiotic systems that include man as a prelude to life in space.

  8. Microcosm experiments of oil degradation by microbial mats.

    PubMed

    de Oteyza, Tirso García; Grimalt, Joan O; Llirós, Marc; Esteve, Isabel

    2006-03-15

    Several microcosm experiments were run in parallel to evaluate the efficiency of microbial mats for crude oil degradation as compared with physico-chemical weathering. The oils used in the experiments constituted representative examples of those currently used for commercial purposes. One was aliphatic and of low viscosity (33.4 American Petroleum Institute degrees, degrees API) and the other was predominantly aromatic, with high sulphur content (ca. 2.7%) and viscosity (16.6 degrees API). After crude oil introduction, the microcosms were kept under cyclic changes in water level to mimic coastal tidal movements. The transformations observed showed that water weathering leads to more effective and rapid elimination of low molecular weight hydrocarbons than microbial mat metabolism, e.g. n-alkanes with chain length shorter than n-pentadecane or n-heptadecane, regular isoprenoid hydrocarbons with chain length lower than C16 or C18 or lower molecular weight naphthalenes. Microbial mats preserved these hydrocarbons from volatilization and water washing. However, hydrocarbons of lower volatility such as the C24-C30 n-alkanes or containing nitrogen atoms, e.g. carbazoles, were eliminated in higher proportion by microbial mats than by water weathering. The strong differences in composition between the two oils used for the experiments were also reflected in significant differences between water weathering and microbial mat biodegradation. Higher oil viscosity seemed to hinder the former but not the later. PMID:15935450

  9. Alteration of Rock Fragments from Columbia River Basalt Microcosms

    NASA Technical Reports Server (NTRS)

    Wentworth, Susan J.; Thomas-Keprta, Kathie L.; Velbel, Michael A.; McKay, David S.; Stevens, Todd O.

    1999-01-01

    During an earlier study, microorganisms were grown microcosms consisting of sterilized chips of Columbia River Basalt (CRB) and natural CRB ground water with its natural microflora; environmental conditions simulated a deep subsurface, anaerobic, dark environment. Subsequent scanning and transmission electron microscope (SEM and TEM) studies revealed the presence of several types of bacteria and biofilm, some of which were mineralized. Some of these biological features are very similar to possible biogenic features found in two meteorites from Mars, ALH84001 (found in Antarctica) and Nakhla (observed to fall in Egypt). Both ALH84001 and Nakhla contain traces of low-temperature aqueous alteration of silicates, oxides, and sulfides. The goals of this study are to use high-resolution field-emission SEM (FE-SEM) to examine the CRB samples for evidence of alteration features similar to those in the martian meteorites, to determine the extent of alteration during the CRB microcosm experiments, and to determine whether effects of biological activity can be distinguished from inorganic effects.

  10. Ecological changes in oral microcosm biofilm during maturation.

    PubMed

    Kim, Young-Seok; Kang, Si-Mook; Lee, Eun-Song; Lee, Ji Hyun; Kim, Bo-Ra; Kim, Baek-Il

    2016-10-01

    The aim of this study was to evaluate the ecological changes in the biofilm at different stages of maturation using 16S rDNA gene amplicon sequencing and to identify correlations between red/green (R/G) fluorescence ratio and ecological changes. An oral microcosm biofilm was initiated from the saliva of a single donor and grown anaerobically for up to 10 days in basal medium mucin. Quantitative light-induced fluorescence analysis was shown that the R/G ratio of the biofilm increased consistently, but the slope rapidly decreased after six days. The bacterial compositions of 10 species also consistently changed over time. However, there was no significant correlation between each bacteria and red fluorescence. The monitoring of the maturation process of oral microcosm biofilm over 10 days revealed that the R/G ratio and the bacterial composition within biofilm consistently changed. Therefore, the R/G fluorescence ratio of biofilm may be related with its ecological change rather than specific bacteria PMID:26950795

  11. Mechanics of intact bone marrow.

    PubMed

    Jansen, Lauren E; Birch, Nathan P; Schiffman, Jessica D; Crosby, Alfred J; Peyton, Shelly R

    2015-10-01

    The current knowledge of bone marrow mechanics is limited to its viscous properties, neglecting the elastic contribution of the extracellular matrix. To get a more complete view of the mechanics of marrow, we characterized intact yellow porcine bone marrow using three different, but complementary techniques: rheology, indentation, and cavitation. Our analysis shows that bone marrow is elastic, and has a large amount of intra- and inter-sample heterogeneity, with an effective Young׳s modulus ranging from 0.25 to 24.7 kPa at physiological temperature. Each testing method was consistent across matched tissue samples, and each provided unique benefits depending on user needs. We recommend bulk rheology to capture the effects of temperature on tissue elasticity and moduli, indentation for quantifying local tissue heterogeneity, and cavitation rheology for mitigating destructive sample preparation. We anticipate the knowledge of bone marrow elastic properties for building in vitro models will elucidate mechanisms involved in disease progression and regenerative medicine. PMID:26189198

  12. Use of in situ microcosms for evaluating reservoir water management options

    SciTech Connect

    French, R.H. ); Cooper, J.J. ); Vigg, S. )

    1988-10-01

    The use of in situ microcosms for performing reservoir trophic studies and aiding in the design of reservoir restoration programs are discussed. The site of this study was Lahontan Reservoir, Nevada, which has experienced water quality problems associated with monospecific blooms of blue-green algae and hypolimnetic dissolved oxygen depletions. In situ microcosms were used to investigate the response of phytoplankton species composition to additions of the nutrients nitrogen, phosphorus, and the phosphorus precipitant aluminum sulfate. At the end of the 16-day experimental period, the microcosms receiving the phosphate treatments yielded the highest standing crops of algae and the greatest percentage composition of blue-green algae. The microcosms receiving the nitrate treatment exhibited greater initial algal concentrations followed by a decline in phytoplankton, which coincided with an increase in the zoo-plankton population. The results presented here suggest that microcosms can be a cost-effective method for assessing reservoir water quality and planning restoration programs.

  13. Single- and dual-porosity modelling of flow in reclaimed mine soil cores with embedded lignitic fragments.

    PubMed

    Gerke, Horst H; Badorreck, Annika; Einecke, Markus

    2009-02-16

    Lignitic mine soils represent a typical two-scale dual-porosity medium consisting of a technogenic mixture of overburden sediments that include lignitic components as dust and as porous fragments embedded within a mostly coarse-textured matrix. Flow and transport processes in such soils are not sufficiently understood to predict the course of soil reclamation or of mine drainage. The objective of this contribution is to identify the most appropriate conceptual model for describing small-scale heterogeneity effects on flow on the basis of the physical structure of the system. Multistep flow experiments on soil cores are analyzed using either mobile-immobile or mobile-mobile type 1D dual-porosity models, and a 3D numerical model that considers a local-scale distribution of fragments. Simulations are compared with time series' of upward infiltration and matric potential heads measured at two depths using miniature tensiometers. The 3D and the 1D dual-permeability models yielded comparable results as long as pressure heads are in local equilibrium; however, could describe either the upward infiltration or the matric potential curves but not both at the same time. The mobile-immobile type dual-porosity model failed to describe the data. A simultaneous match with pressure heads and upward infiltration data could only be obtained with the 1D dual-permeability model (i.e., mobile-mobile) by assuming an additional restriction of the inter-domain water transfer. These results indicate that for unsaturated flow conditions at higher matric potential heads (i.e., here >-40 hPa), water in a restricted part of the fragment domain must be more mobile as compared to water in the sandy matrix domain. Closer inspections of the pore system and first neutron radiographic imaging support the hypothesis that a more continuous pore region exists at these pressure heads in the vicinity of the lignitic fragments possibly formed by fragment contacts and a lignitic dust interface

  14. Temporal variation of magnetotactic bacterial communities in two freshwater sediment microcosms.

    PubMed

    Lin, Wei; Pan, Yongxin

    2010-01-01

    Magnetotactic bacteria (MTB), which can mineralize nanosized magnetite or greigite crystals within cells, play important roles in biogeochemical processes, for example iron and sulfur cycling, and depositional remanent magnetization acquisitions. Despite decades of research, the knowledge of MTB distribution and ecology is still limited. In the present study, we investigated the temporal variation of MTB communities in freshwater sediment microcosms based on 16S rRNA genes and unifrac analyses. Two microcosms (MY8 and MY11) collected from two separate sites in Lake Miyun (Beijing, China) were analyzed. The majority of retrieved sequences belonged to alphaproteobacterial magnetotactic cocci in both microcosms (representing 64.29% of clones from MY8 and 100% of clones from MY11), whereas so-called 'Magnetobacterium bavaricum'-like MTB affiliated within Nitrospira phylum were exclusively found in microcosm MY8. Over a 3-month period, the temporal variation of MTB communities was evident in both microcosms. In addition, the phylogenetic discrepancy of MTB communities between two microcosms is more prominent than that of the same microcosm at different times, implying adaptation of MTB phylogenetic lineages to specific microenvironments. Among the physical-chemical parameters measured, a strong correlation was shown between nitrate and the main genetic variability of MTB communities, indicating that nitrate may influence the occurrence of MTB phylogenetic lineages in natural environments. PMID:19909346

  15. Use of microcosms to determine the survival of the fish pathogen Tenacibaculum maritimum in seawater.

    PubMed

    Avendaño-Herrera, Ruben; Irgang, Rute; Magariños, Beatriz; Romalde, Jesús L; Toranzo, Alicia E

    2006-05-01

    The survival of the fish pathogen Tenacibaculum maritimum in different seawater microcosms was investigated during 160 days. The persistence of culturable cells was greater in sterile than in natural seawater. Standard plate counts showed that T. maritimum survived in sterile seawater for more than 5 months at concentration around 10(3) cfu ml(-1). However, T. maritimum proved to be very labile in non-sterile seawater, rendering culturable cells no longer than 5 days. These results were confirmed when DNA-based methods were applied. Regardless of the microcosms used, epifluorescence microscopy counts remained at about 10(6) cells ml(-1) throughout the experiment, even though we can not distinguish T. maritimum in the case of non-sterile microcosms. Resuscitation assays with addition of fresh medium to non-sterile microcosms did not favour the recovery of T. maritimum on solid media. Although morphological changes from filamentous to spheres were observed after 3 days in the non-sterile microcosms, in the case of the sterile microcosms this change was observed at the sixth day. The biochemical, physiological, serological and genetic characteristics were unaffected in the sterile microcosms. The overall results contribute to a better understanding of the behaviour of T. maritimum in natural seawater and suggest that the aquatic bacterial population play an important role in the survival of this fish pathogen. PMID:16623748

  16. Microbial community analysis of switchgrass planted and unplanted soil microcosms displaying PCB dechlorination

    PubMed Central

    Liang, Yi; Meggo, Richard; Hu, Dingfei; Schnoor, Jerald L.; Mattes, Timothy E.

    2015-01-01

    Polychlorinated biphenyls (PCBs) pose potential risks to human and environmental health because they are carcinogenic, persistent and bioaccumulative. In this study we investigated bacterial communities in soil microcosms spiked with PCB 52, 77 and 153. Switchgrass (Panicum virgatum) was employed to improve overall PCB removal and redox cycling (i.e. sequential periods of flooding followed by periods of no flooding) was performed in an effort to promote PCB dechlorination. Lesser chlorinated PCB transformation products were detected in all microcosms, indicating the occurrence of PCB dechlorination. Terminal restriction fragment length polymorphism (T-RFLP) and clone library analysis showed that PCB spiking, switchgrass planting and redox cycling affected the microbial community structure. Putative organohalide-respiring Chloroflexi populations, which were not found in unflooded microcosms, were enriched after two weeks of flooding in the redox-cycled microcosms. Sequences classified as Geobacter sp. were detected in all microcosms, and were most abundant in the switchgrass-planted microcosm spiked with PCB congeners. The presence of possible organohalide-respiring bacteria in these soil microcosms suggests they play a role in PCB dechlorination therein. PMID:25820643

  17. Biodegradation of veterinary ionophore antibiotics in broiler litter and soil microcosms.

    PubMed

    Sun, Peizhe; Cabrera, Miguel L; Huang, Ching-Hua; Pavlostathis, Spyros G

    2014-01-01

    Ionophore antibiotics (IPAs) are polyether compounds used in broiler feed to promote growth and control coccidiosis. Most of the ingested IPAs are excreted into broiler litter (BL), a mixture of excreta and bedding material. BL is considered a major source of IPAs released into the environment as BL is commonly used to fertilize agricultural fields. This study investigated IPA biodegradation in BL and soil microcosms, as a process affecting the fate of IPAs in the environment. The study focused on the most widely used IPAs, monensin (MON), salinomycin (SAL), and narasin (NAR). MON was stable in BL microcosms at 24-72% water content (water/wet litter, w/w) and 35-60 °C, whereas SAL and NAR degraded under certain conditions. Factor analysis was conducted to delineate the interaction of water and temperature on SAL and NAR degradation in the BL. A major transformation product of SAL and NAR was identified. Abiotic reaction(s) were primarily responsible for the degradation of MON and SAL in nonfertilized soil microcosms, whereas biodegradation contributed significantly in BL-fertilized soil microcosms. SAL biotransformation in soil microcosms yielded the same product as in the BL microcosms. A new primary biotransformation product of MON was identified in soil microcosms. A field study showed that MON and SAL were stable during BL stacking, whereas MON degraded after BL was applied to grassland. The biotransformation product of MON was also detected in the top soil layer where BL was applied. PMID:24494860

  18. Introduction of anaerobic dechlorinating bacteria into soil slurry microcosms and nested-PCR monitoring.

    PubMed Central

    el Fantroussi, S; Mahillon, J; Naveau, H; Agathos, S N

    1997-01-01

    Desulfomonile tiedjei and Desulfitobacterium dehalogenans were chosen as model bacteria to demonstrate the introduction of an anaerobic microbia reductive dechlorination activity into nonsterile soil slurry microcosms by inoculation. De novo 3-chlorobenzoate dechlorination activity was established with the bacterium D. tiedjei in microcosms normally devoid of this dechlorination capacity. The addition of D. tiedjei to microcosms supplemented with 20 mM pyruvate as the cosubstrate resulted in total biotransformation of 1.5 mM 3-chlorobenzoate within 7 days. The introduction of the bacterium Desulfitobacterium dehalogenans into nonsterile microcosms resulted in a shortening of the period required for dechlorination activity to be established. In microcosms inoculated with Desulfitobacterium dehalogenans, total degradation of 6 mM 3-chloro-4-hydroxy phenoxyacetic acid (3-Cl-4-OHPA) was observed after 4 days in contrast to the result in noninoculated microcosms, where the total degradation of 3-Cl-4-OHPA by indigenous microorganisms was observed after 11 days. Both externally introduced bacterial strains were detected in soil slurry microcosms by a nested-PCR methodology. PMID:9023963

  19. Saprophytic growth of inoculated Frankia sp. in soil microcosms.

    PubMed

    Mirza, Babur S; Welsh, Allana; Hahn, Dittmar

    2007-12-01

    The potential of two Frankia strains to grow saprophytically was studied in nonsterile soil microcosms with ground leaf litter of Alnus glutinosa as the sole carbon and nitrogen sources. Strains Ag45/Mut15 and ArI3, which represent two taxonomic subgroups within the Alnus host infection group were inoculated alone, or together to investigate potential competition. Their growth was analyzed by in situ and dot-blot hybridization. A significant increase in cell numbers and filament length was observed during the first 6 weeks after inoculation for strain Ag45/Mut15, both alone and in mixed culture with strain ArI3, followed by a decrease until the end of the study after 12 weeks. The number of filaments remained unchanged. In contrast, the cell numbers and filament length of strain ArI3 were reduced significantly during the first 2 weeks and were undetectable for the remainder of the study. These results were comparable with those obtained in sterile mineral medium amended with leaf litter of A. glutinosa, although reductions in cell numbers and filament length were less pronounced than in soil microcosms. In concomitant control studies without leaf litter amendments for both experimental setups, filaments of both strains could only be detected immediately after inoculation. These results were matched in all experimental setups by concomitant shifts in the rRNA content of both strains, i.e., an immediate decline in the rRNA content for strain ArI3 after inoculation, and an increase in the rRNA content, followed by a late decline during incubation for strain Ag45/Mut15. These results demonstrated that Frankia strain Ag45/Mut15 could grow saprophytically in soil with complex carbon and nitrogen sources such as leaf litter, while the growth of strain ArI3 was not supported. PMID:17916077

  20. ANAEROBIC SOIL DISINFESTATION IN MICROCOSMS OF TWO SANDY SOILS.

    PubMed

    Stremińska, M A; Runia, W T; Termorshuizen, A J; Feil, H; Van Der Wurff, A W G

    2014-01-01

    In recent years, anaerobic soil disinfestation (ASD) has been proposed as an alternative control method of soil-borne plant pathogens. It involves adding a labile carbon source, irrigating the soil to stimulate decomposition of organic material and then covering the soil with air-tight plastic to limit gas exchange. During the ASD process, soil microorganisms switch from aerobic to anaerobic metabolism. As a result, by-products of anaerobic metabolism are released into the soil environment such as various organic acids and gases. These by-products are reported to have a negative effect on survival of soil-borne plant pathogens. However, the efficacy of ASD to reduce soil-borne pathogens in practice may vary significantly. Therefore, we studied the efficacy of the ASD process in two different soils. In addition, it was investigated whether a pre-treatment with an anaerobic bacterial inoculum prior to ASD affected the efficacy of the process. Two sandy soils (dune sand and glacial sand) were inoculated in 2 L soil microcosms. We tested the efficacy of ASD treatment against the potato cyst nematode Globodera pallida. For each soil, three treatments were used: control treatment (no Herbie addition, aerobic incubation), ASD 1 (organic substrate addition, anaerobic incubation) and ASD 2 (organic substrate and anaerobic bacterial inoculum addition, anaerobic incubation). Soil microcosms were incubated in the dark at 20°C for two weeks. We observed that anaerobic soil disinfestation treatments were highly effective against Potato Cyst Nematode (PCN), with pathogen being eradicated totally in all but one ASD treatment (glacial sand ASD2) within two weeks. The relative abundance of Firmicutes (spore-forming bacteria, often fermentative) in total bacteria increased significantly in ASD treated soils. Numbers of these bacteria correlated positively with increased concentrations of acetic and butyric acids in soil water phase in ASD treatments. PMID:26084078

  1. Acidic sandy soil improvement with biochar - A microcosm study.

    PubMed

    Molnár, Mónika; Vaszita, Emese; Farkas, Éva; Ujaczki, Éva; Fekete-Kertész, Ildikó; Tolner, Mária; Klebercz, Orsolya; Kirchkeszner, Csaba; Gruiz, Katalin; Uzinger, Nikolett; Feigl, Viktória

    2016-09-01

    Biochar produced from a wide range of organic materials by pyrolysis has been reported as a means to improve soil physical properties, fertility and crop productivity. However, there is a lack of studies on the complex effects of biochar both on the degraded sandy soil physico-chemical properties and the soil biota as well as on toxicity, particularly in combined application with fertilizer and compost. A 7-week microcosm experiment was conducted to improve the quality of an acidic sandy soil combining variations in biochar types and amounts, compost and fertilizer application rates. The applied biochars were produced from different feedstocks such as grain husks, paper fibre sludge and wood screenings. The main purpose of the microcosm experiment was to assess the efficiency and applicability of different biochars as soil amendment prior to field trials and to choose the most efficient biochar to improve the fertility, biological activity and physical properties of acidic sandy soils. We complemented the methodology with ecotoxicity assessment to evaluate the possible risks to the soil as habitat for microbes, plants and animals. There was clear evidence of biochar-soil interactions positively affecting both the physico-chemical properties of the tested acidic sandy soil and the soil biota. Our results suggest that the grain husk and the paper fibre sludge biochars applied to the tested soil at 1% and 0.5 w/w% rate mixed with compost, respectively can supply a more liveable habitat for plants and soil living animals than the acidic sandy soil without treatment. PMID:26850860

  2. BIODEGRADATION OF POLYCYCLIC AROMATIC HYDROCARBONS (PAH) FROM CRUDE OIL IN SANDY-BEACH MICROCOSMS.

    EPA Science Inventory

    Though the lower n-alkanes are considered the most degradable components of crude oil, our experiments with microcosms simulating oiled beaches showed substantial depletion of fluorene, phenanthrene, dibenzothiophene, and other PAH in control treatments consisting of raw seawater...

  3. Stability and resilience of oral microcosms toward acidification and Candida outgrowth by arginine supplementation.

    PubMed

    Koopman, Jessica E; Röling, Wilfred F M; Buijs, Mark J; Sissons, Christopher H; ten Cate, Jacob M; Keijser, Bart J F; Crielaard, Wim; Zaura, Egija

    2015-02-01

    Dysbiosis induced by low pH in the oral ecosystem can lead to caries, a prevalent bacterial disease in humans. The amino acid arginine is one of the pH-elevating agents in the oral cavity. To obtain insights into the effect of arginine on oral microbial ecology, a multi-plaque "artificial mouth" (MAM) biofilm model was inoculated with saliva from a healthy volunteer and microcosms were grown for 4 weeks with 1.6 % (w/v) arginine supplement (Arginine) or without (Control), samples were taken at several time-points. A cariogenic environment was mimicked by sucrose pulsing. The bacterial composition was determined by 16S rRNA gene amplicon sequencing, the presence and amount of Candida and arginine deiminase system genes arcA and sagP by qPCR. Additionally, ammonium and short-chain fatty acid concentrations were determined. The Arginine microcosms were dominated by Streptococcus, Veillonella, and Neisseria and remained stable in time, while the composition of the Control microcosms diverged significantly in time, partially due to the presence of Megasphaera. The percentage of Candida increased 100-fold in the Control microcosms compared to the Arginine microcosms. The pH-raising effect of arginine was confirmed by the pH and ammonium results. The abundances of sagP and arcA were highest in the Arginine microcosms, while the concentration of butyrate was higher in the Control microcosms. We demonstrate that supplementation with arginine serves a health-promoting function; it enhances microcosm resilience toward acidification and suppresses outgrowth of the opportunistic pathogen Candida. Arginine facilitates stability of oral microbial communities and prevents them from becoming cariogenic. PMID:25433583

  4. Sunlight inactivation of Escherichia coli in waste stabilization microcosms in a sahelian region (Ouagadougou, Burkina Faso).

    PubMed

    Maïga, Ynoussa; Denyigba, Kokou; Wethe, Joseph; Ouattara, Aboubakar Sidiki

    2009-02-01

    Experiments on sunlight inactivation of Escherichia coli were conducted from November 2006 to June 2007 in eight outdoors microcosms with different depths filled with maturation pond wastewater in order to determine pond depth influence on sunlight inactivation of E. coli. The long-term aim was to maximize sunlight inactivation of waterborne pathogens in waste stabilization ponds (WSPs) in sahelian regions where number of sunny days enable longer exposure of wastewater to sunlight. The inactivation was followed during daylight from 8.00 h to 17.00 h and during the night. Sunlight inactivation rates (K(S)), as a function of cumulative global solar radiation (insolation), were 16 and 24 times higher than the corresponding dark inactivation (K(D)) rates, respectively in cold and warm season. In warm season, E. coli was inactivated far more rapidly. Inactivation of E. coli follows the evolution of radiation during the day. In shallow depth microcosms, E. coli was inactivated far more rapidly than in high depth microcosms. The physical chemical parameters [pH, dissolved oxygen (DO)] of microcosms water were higher in shallow depth microcosms than in high depth microcosms suggesting a synergistic effect of sunlight and these parameters to damage E. coli. To increase the efficiency of the elimination of waterborne bacteria, the use of maturation ponds with intermediate depths (0.4m) would be advisable in view of the high temperatures and thus evaporation recorded in sahelian regions. PMID:19084427

  5. Microcosm procedure for determining safe levels of chemical exposure in shallow-water communities

    SciTech Connect

    Giddings, J.M.

    1985-01-01

    This paper describes a method for determining safe levels of chemical exposure in shallow-water communities, using laboratory microcosms as test subjects. The safe level is considered to be the maximum exposure that causes no persistent, ecologically significant changes in the ecosystem. In experiments completed at Oak Ridge National Laboratory, microcosm-derived estimates of safe exposure levels were confirmed using outdoor artificial ponds, which suggests that the microcosm procedure can be an efficient and economical means of determining safe levels for shallow-water communities. Details of microcosm construction, techniques for monitoring ecological variables in microcosms, and an experimental design for determining safe exposure levels are provided here. The microcosms are assembled by transferring components of natural ecosystems to 80-litre aquaria in a controlled laboratory environment. The communities that develop in these systems are typically dominated by common, cosmopolitan littoral species of macrophytes, algae, and invertebrates. Methods are described for measuring changes in water chemistry, phytoplankton, periphyton, macrophytes, zooplankton, and ecosystem production and respiration. By monitoring these variables over a gradient of pollutant exposure levels, the safe level can be determined accurately and precisely. 16 refs., 2 figs.

  6. Microcosm and in situ field studies of enhanced biotransformation of trichloroethylene by phenol-utilizing microorganisms.

    PubMed Central

    Hopkins, G D; Semprini, L; McCarty, P L

    1993-01-01

    The ability of different aerobic groundwater microorganisms to cometabolically degrade trichloroethylene (TCE), 1,2-cis-dichloroethylene (c-DCE), and 1,2-trans-dichloroethylene (t-DCE) was evaluated both in groundwater-fed microcosms and in situ in a shallow aquifer. Microcosms amended with phenol or toulene were equally effective in removing c-DCE (> 90%) followed by TCE (60 to 70%), while the microcosm fed methane was most effective in removing t-DCE (> 90%). The microcosm fed ammonia was the least effective. None of the microcosms effectively degraded 1,1,1-trichloroethane. At the Moffett Field groundwater test site, in situ removal of c-DCE and TCE coincided with biostimulation through phenol and oxygen injection and utilization, with c-DCE removed more rapidly than TCE. Greater TCE and c-DCE removal was observed when the phenol concentration was increased. Over 90% removal of c-DCE and TCE was observed in the 2-m biostimulated zone. This compares with 40 to 50% removal of c-DCE and 15 to 25% removal of TCE achieved by methane-grown microorganisms previously evaluated in an adjacent in situ test zone. The in situ removal with phenol-grown microorganisms agrees qualitatively with the microcosm studies, with the rates and extents of removal ranked as follows: c-DCE > TCE > t-DCE. These studies demonstrate the potential for in situ TCE bioremediation using microorganisms grown on phenol. PMID:8357259

  7. Stereoselective biodegradation of amphetamine and methamphetamine in river microcosms.

    PubMed

    Bagnall, John; Malia, Louis; Lubben, Anneke; Kasprzyk-Hordern, Barbara

    2013-10-01

    Here presented for the first time is the enantioselective biodegradation of amphetamine and methamphetamine in river microcosm bioreactors. The aim of this investigation was to test the hypothesis that mechanisms governing the fate of amphetamine and methamphetamine in the environment are mostly stereoselective and biological in nature. Several bioreactors were studied over the duration of 15 days (i) in both biotic and abiotic conditions, (ii) in the dark or exposed to light and (iii) in the presence or absence of suspended particulate matter. Bioreactor samples were analysed using SPE-chiral-LC-(QTOF)MS methodology. This investigation has elucidated the fundamental mechanism for degradation of amphetamine and methamphetamine as being predominantly biological in origin. Furthermore, stereoselectivity and changes in enantiomeric fraction (EF) were only observed under biotic conditions. Neither amphetamine nor methamphetamine appeared to demonstrate adsorption to suspended particulate matter. Our experiments also demonstrated that amphetamine and methamphetamine were photo-stable. Illicit drugs are present in the environment at low concentrations but due to their pseudo-persistence and non-racemic behaviour, with two enantiomers revealing significantly different potency (and potentially different toxicity towards aquatic organisms) the risk posed by illicit drugs in the environment should not be under- or over-estimated. The above results demonstrate the need for re-evaluation of the procedures utilised in environmental risk assessment, which currently do not recognise the importance of the phenomenon of chirality in pharmacologically active compounds. PMID:23886544

  8. No evidence of aquatic priming effects in hyporheic zone microcosms.

    PubMed

    Bengtsson, Mia M; Wagner, Karoline; Burns, Nancy R; Herberg, Erik R; Wanek, Wolfgang; Kaplan, Louis A; Battin, Tom J

    2014-01-01

    The priming effect refers to quantitative changes in microbial decomposition of recalcitrant organic matter upon addition of labile organic matter and is a phenomenon that mainly has been reported and debated in soil science. Recently, priming effects have been indicated in aquatic ecosystems and have received attention due to the potential significance for ecosystem carbon budgets. Headwater stream biofilms, which are important degraders of both allochthonous, presumably recalcitrant, organic matter and labile autochthonous organic matter, may be sites where priming effects are important in aquatic environments. We have experimentally tested for priming effects in stream biofilms within microcosms mimicking the stream hyporheic zone. A (13)C labeled model allochthonous carbon source was used in combination with different carbon sources simulating autochthonous inputs. We did not detect changes in respiration, removal or incorporation of allochthonous organic matter in response to autochthonous treatments, thus not supporting the occurrence of priming effects under the experimental conditions. This study is the first to address priming effects in the hyporheic zone, and one of very few studies quantitatively assessing aquatic priming effects. The results contrast with existing studies, which highlights the need for quantitative approaches to determine the importance of priming effects in aquatic environments. PMID:24898319

  9. Arsenic mobilization from sediments in microcosms under sulfate reduction.

    PubMed

    Sun, Jing; Quicksall, Andrew N; Chillrud, Steven N; Mailloux, Brian J; Bostick, Benjamin C

    2016-06-01

    Arsenic is often assumed to be immobile in sulfidic environments. Here, laboratory-scale microcosms were conducted to investigate whether microbial sulfate reduction could control dissolved arsenic concentrations sufficiently for use in groundwater remediation. Sediments from the Vineland Superfund site and the Coeur d'Alene mining district were amended with different combination of lactate and sulfate and incubated for 30-40 days. In general, sulfate reduction in Vineland sediments resulted in transient and incomplete arsenic removal, or arsenic release from sediments. Sulfate reduction in the Coeur d'Alene sediments was more effective at removing arsenic from solution than the Vineland sediments, probably by arsenic substitution and adsorption within iron sulfides. X-ray absorption spectroscopy indicated that the Vineland sediments initially contained abundant reactive ferrihydrite, and underwent extensive sulfur cycling during incubation. As a result, arsenic in the Vineland sediments could not be effectively converted to immobile arsenic-bearing sulfides, but instead a part of the arsenic was probably converted to soluble thioarsenates. These results suggest that coupling between the iron and sulfur redox cycles must be fully understood for in situ arsenic immobilization by sulfate reduction to be successful. PMID:27037658

  10. Microcosm investigation on phytoremediation of Cr using Azolla pinnata.

    PubMed

    Rai, Prabhat Kumar

    2010-01-01

    The extent of Chromium (Cr) pollution in Singrauli industrial region, India was assessed and phytoremediation capacity of a small water fern, Azolla pinnata R.BR (Azollaceae) was observed to purify waters polluted by Cr under microcosm condition. Azolla pinnata endemic to India is a potential hyper-accumulator of heavy metals. During 13 days of the experiment the fern was grown in the aqueous medium containing Cr3+ and CrO4(2-) ions, each in a concentration 0.5, 1.0, and 3.0 mg L(-1). The presence of these ions caused a + 3.1 to -37.5% inhibition of Azolla pinnata growth in comparison to the control. After 13 days of the experiment, metal contents in the solution was decreased up to 70% (CrO4(2-) 3.0 mg L(-1) treatment) to 88% (CrO4(2-) 0.5 mg L(-1) treatment). In the Azolla pinnata tissues, the concentration of couple of the ionic forms of Cr under investigation ranged from 415 to 1095 mg kg(-1) dry mass (dm); the highest level being found for Cr (III) containing solution. PMID:20734631

  11. Antiseptics and microcosm biofilm formation on titanium surfaces.

    PubMed

    Verardi, Georgia; Cenci, Maximiliano Sérgio; Maske, Tamires Timm; Webber, Bruna; Santos, Luciana Ruschel dos

    2016-01-01

    Oral rehabilitation with osseointegrated implants is a way to restore esthetics and masticatory function in edentulous patients, but bacterial colonization around the implants may lead to mucositis or peri-implantitis and consequent implant loss. Peri-implantitis is the main complication of oral rehabilitation with dental implants and, therefore, it is necessary to take into account the potential effects of antiseptics such as chlorhexidine (CHX), chloramine T (CHT), triclosan (TRI), and essential oils (EO) on bacterial adhesion and on biofilm formation. To assess the action of these substances, we used the microcosm technique, in which the oral environment and periodontal conditions are simulated in vitro on titanium discs with different surface treatments (smooth surface - SS, acid-etched smooth surface - AESS, sand-blasted surface - SBS, and sand-blasted and acid-etched surface - SBAES). Roughness measurements yielded the following results: SS: 0.47 µm, AESS: 0.43 µm, SB: 0.79 µm, and SBAES: 0.72 µm. There was statistical difference only between SBS and AESS. There was no statistical difference among antiseptic treatments. However, EO and CHT showed lower bacterial counts compared with the saline solution treatment (control group). Thus, the current gold standard (CHX) did not outperform CHT and EO, which were efficient in reducing the biofilm biomass compared with saline solution. PMID:26981756

  12. Bacterial Community Response to Petroleum Hydrocarbon Amendments in Freshwater, Marine, and Hypersaline Water-Containing Microcosms

    PubMed Central

    Jurelevicius, Diogo; Alvarez, Vanessa Marques; Marques, Joana Montezano; de Sousa Lima, Laryssa Ribeiro Fonseca; Dias, Felipe de Almeida

    2013-01-01

    Hydrocarbon-degrading bacterial communities from freshwater, marine, and hypersaline Brazilian aquatic ecosystems (with water salinities corresponding to 0.2%, 4%, and 5%, respectively) were enriched with different hydrocarbons (heptadecane, naphthalene, or crude oil). Changes within the different microcosms of bacterial communities were analyzed using cultivation approaches and molecular methods (DNA and RNA extraction, followed by genetic fingerprinting and analyses of clone libraries based on the 16S rRNA-coding gene). A redundancy analysis (RDA) of the genetic fingerprint data and a principal component analysis (PCA) of the clone libraries revealed hydrocarbon-enriched bacterial communities specific for each ecosystem studied. However, within the same ecosystem, different bacterial communities were selected according to the petroleum hydrocarbon used. In general, the results demonstrated that Acinetobacter and Cloacibacterium were the dominant genera in freshwater microcosms; the Oceanospirillales order and the Marinobacter, Pseudomonas, and Cycloclasticus genera predominated in marine microcosms; and the Oceanospirillales order and the Marinobacter genus were selected in the different hydrocarbon-containing microcosms in hypersaline water. Determination of total petroleum hydrocarbons (TPHs) in all microcosms after 32 days of incubation showed a decrease in the hydrocarbon concentration compared to that for the controls. A total of 50 (41.3%) isolates from the different hydrocarbon-contaminated microcosms were associated with the dominant operational taxonomic units (OTUs) obtained from the clone libraries, and their growth in the hydrocarbon contaminating the microcosm from which they were isolated as the sole carbon source was observed. These data provide insight into the general response of bacterial communities from freshwater, marine, and hypersaline aquatic ecosystems to petroleum hydrocarbon contamination. PMID:23872573

  13. Phosphate release from seasonally flooded soils: a laboratory microcosm study.

    PubMed

    Young, E O; Ross, D S

    2001-01-01

    Phosphorus derived from agricultural practices has been targeted as a leading cause of water quality degradation in Lake Champlain. Mobilization of P from seasonally flooded agricultural soils is a concern. Using 14 soils from a research farm in New York's Champlain Valley, we characterized the available P status, extractable Fe and Al, P sorption capacities, and soluble phosphate release in flooded laboratory microcosms. Quantities of NH4-acetate available P ranged from 3 to 100 mg kg(-1) and fluoride-extractable P from 10 to 211 mg kg(-1). Flooding soils induced significant release of phosphate to the porewater over a 60- to 90-d period in 13 of the 14 soils studied. Porewater phosphate increases ranged from 2.2 to 27.0 times the initial phosphate concentrations. However, floodwater phosphate increases were much lower, with a maximum of 3.6 times the initial concentration. Average porewater phosphate concentrations over the flooding period ranged from 0.046 to 7.0 mg L(-1) and average floodwater P from 0.032 to 3.70 mg L(-1). Ammonium-acetate P and the degree of phosphorus saturation (DPS) were highly correlated with the average porewater and floodwater phosphate concentration. Average ratio of porewater to floodwater phosphate concentrations ranged from 1.0 to 3.3. Five soils that were lower in fluoride-extractable P had increasing porewater phosphate accompanied by increasing porewater Fe2+ and decreasing floodwater phosphate. Results suggest that P solubility and mobility were a function of both the available P status and redox cycling. PMID:11215671

  14. Carbazole degradation in the soil microcosm by tropical bacterial strains

    PubMed Central

    Salam, Lateef B.; Ilori, Matthew O.; Amund, Olukayode O.

    2015-01-01

    In a previous study, three bacterial strains isolated from tropical hydrocarbon-contaminated soils and phylogenetically identified as Achromobacter sp. strain SL1, Pseudomonas sp. strain SL4 and Microbacterium esteraromaticum strain SL6 displayed angular dioxygenation and mineralization of carbazole in batch cultures. In this study, the ability of these isolates to survive and enhance carbazole degradation in soil were tested in field-moist microcosms. Strain SL4 had the highest survival rate (1.8 x 107 cfu/g) after 30 days of incubation in sterilized soil, while there was a decrease in population density in native (unsterilized) soil when compared with the initial population. Gas chromatographic analysis after 30 days of incubation showed that in sterilized soil amended with carbazole (100 mg/kg), 66.96, 82.15 and 68.54% were degraded by strains SL1, SL4 and SL6, respectively, with rates of degradation of 0.093, 0.114 and 0.095 mg kg−1 h−1. The combination of the three isolates as inoculum in sterilized soil degraded 87.13% carbazole at a rate of 0.121 mg kg−1 h−1. In native soil amended with carbazole (100 mg/kg), 91.64, 87.29 and 89.13% were degraded by strains SL1, SL4 and SL6 after 30 days of incubation, with rates of degradation of 0.127, 0.121 and 0.124 mg kg−1 h−1, respectively. This study successfully established the survivability (> 106 cfu/g detected after 30 days) and carbazole-degrading ability of these bacterial strains in soil, and highlights the potential of these isolates as seed for the bioremediation of carbazole-impacted environments. PMID:26691461

  15. Multilevel samplers as microcosms to assess microbial response to biostimulation.

    PubMed

    Baldwin, B R; Peacock, A D; Park, M; Ogles, D M; Istok, J D; McKinley, J P; Resch, C T; White, D C

    2008-01-01

    Passive multilevel samplers (MLS) containing a solid matrix for microbial colonization were used as in situ microcosms in conjunction with a push-pull biostimulation experiment designed to promote biological U(VI) and Tc(VII) reduction. MLS were deployed at 24 elevations in the injection well and two downgradient wells to investigate the spatial variability in microbial community composition and growth prior to and following biostimulation. The microbial community was characterized by real-time quantitative polymerase chain reaction (Q-PCR) quantification of bacteria, NO(3)(-)-reducing bacteria (nirS and nirK), delta-proteobacteria, Geobacter sp., and methanogens (mcrA). Pretest cell densities were low overall but varied substantially with significantly greater bacterial populations detected at circumneutral pH (t-test, alpha= 0.05), suggesting carbon substrate and low pH limitations of microbial activity. Although pretest cell densities were low, denitrifying bacteria were dominant members of the microbial community. Biostimulation with an ethanol-amended ground water resulted in concurrent NO(3)(-) and Tc(VII) reduction, followed by U(VI) reduction. Q-PCR analysis of MLS revealed significant (1 to 2 orders of magnitude, Mann-Whitney U-test, alpha= 0.05) increases in cell densities of bacteria, denitrifiers, delta-proteobacteria, Geobacter sp., and methanogens in response to biostimulation. Traditionally, characterization of sediment samples has been used to investigate the microbial community response to biostimulation; however, collection of sediment samples is expensive and not conducive to deep aquifers or temporal studies. The results presented demonstrate that push-pull tests with passive MLS provide an inexpensive approach to determine the effect of biostimulation on contaminant concentrations, geochemical conditions, and the microbial community composition and function. PMID:18194316

  16. Microcosms metacommunities in river network: niche effects and biodiversity

    NASA Astrophysics Data System (ADS)

    Giometto, A.; Carrara, F.; Altermatt, F.; Rinaldo, A.

    2012-04-01

    Many highly diverse landscapes exhibit hierarchical spatial structures that are shaped by geomorphological processes. Riverine ecosystems, among the most diverse habitats on Earth, represent an outstanding example of such mechanisms. In these landscapes, in which connectivity directly influences metacommunity processes, habitat capacity contributes to control biodiversity at several levels. A previous study has already highlighted the effect of connectivity on species distribution at local and regional scales, but habitat capacity was kept uniform. We studied the interaction of connectivity and habitat capacity in an aquatic microcosm experiment, in which microbial communities were grown in 36-well culture plates connected by dispersal. Dispersal occurred by periodic transfer of culture medium among connected local communities, following river network topology. The effect of habitat capacity in these landscapes was investigated by comparing three different spatial configurations of local community volumes: 1. Power law distributed volumes, according to drainage area. 2. Spatial random permutation of the volumes in the above configuration. 3. Equal distribution of volumes (preserving the total volume with respect to the above configurations). The net effect of habitat capacity on community composition was isolated in a control treatment in which communities were kept isolated for the whole duration of the experiment. In all treatments we observed that varying volumes induced niche effects: some protozoan species preferentially occupied larger nodes (systematically in isolation). Nevertheless, there is evidence that position along the network played a significant role in shaping biodiversity patterns. Size distribution measurements for each community were taken with a CASY cell counter, and species abundances data on log scale precision were collected by direct microscope observation.

  17. Toxic effects of isoproturon on periphyton communities a microcosm study

    NASA Astrophysics Data System (ADS)

    Schmitt-Jansen, Mechthild; Altenburger, Rolf

    2005-02-01

    Coastal and estuarine ecosystems are increasingly exposed to herbicide contamination. To study the potential risks of these pollutants, the establishment of periphyton communities under exposure of a concentration series of isoproturon in a range of 0.0024-0.312 mg L -1 was investigated in a microcosm study. After two weeks of growth, chronic effects on biomass development, measured as Chl a fluorescence, taxonomic composition and photosynthetic capacity of PS II of attached microalgae were analysed using a pulse-amplitude modulated (PAM) fluorescence-based method. Algal classes were differentiated according to their pigment systems using four excitation wavelengths. Biomass remained constant up to pre-exposure concentrations of 0.02 mg L -1 isoproturon but decreased within one order of magnitude at the highest test concentration. Algal classes shifted from diatoms to chlorophytes at pre-exposure concentrations of 0.02-0.39 mg L -1. Community structure of diatoms representing the dominant group of attached algae at lower test concentrations was studied by microscopic analysis revealing that species numbers were highest at lowest test concentrations as compared to controls. At higher test concentrations Navicula halophila dominated with 89% of the diatom biomass but was abnormally shaped. Pollution-induced community tolerance (PICT) of periphyton to isoproturon was determined by short-term inhibition tests of photosynthesis. Pre-exposed communities increased their effect concentrations (EC 50) up to threefold within the 0.039 mg L -1 pre-treatment. Our results suggest that attached microalgal communities have a high potential of tolerance development to isoproturon at lower levels of contamination due to the replacement of sensitive species by more tolerant algae, although these species seemed to be affected too. We conclude that herbicide concentrations in river basins, estuaries or coastal zones may change community structure and primary production of

  18. Properties of Subsurface Soil Cores from Four Geologic Provinces Surrounding Mars Desert Research Station, Utah: Characterizing Analog Martian Soil in a Human Exploration Scenario

    NASA Technical Reports Server (NTRS)

    Stoker, C. R.; Clarke, J. D. A.; Direito, S.; Foing, B.

    2011-01-01

    The DOMEX program is a NASA-MMAMA funded project featuring simulations of human crews on Mars focused on science activities that involve collecting samples from the subsurface using both manual and robotic equipment methods and analyzing them in the field and post mission. A crew simulating a human mission to Mars performed activities focused on subsurface science for 2 weeks in November 2009 at Mars Desert Research Station near Hanksville, Utah --an important chemical and morphological Mars analog site. Activities performed included 1) survey of the area to identify geologic provinces, 2) obtaining soil and rock samples from each province and characterizing their mineralogy, chemistry, and biology; 3) site selection and reconnaissance for a future drilling mission; 4) deployment and testing of Mars Underground Mole, a percussive robotic soil sampling device; and 5) recording and analyzing how crew time was used to accomplish these tasks. This paper summarizes results from analysis of soil cores

  19. Lipid diffusibility in the intact erythrocyte membrane.

    PubMed Central

    Bloom, J A; Webb, W W

    1983-01-01

    The lateral diffusion of fluorescent lipid analogues in the plasma membrane of intact erythrocytes from man, mouse, rabbit, and frog has been measured by fluorescence photobleaching recovery (FPR). Intact cells from dystrophic, normoblastic, hemolytic, and spherocytotic mouse mutants; from hypercholesterolemic rabbits and humans; and from prenatal, neonatal, and juvenile mice have been compared with corresponding normals. The lateral diffusion coefficient (D) for 3,3'-dioctadecylindodicarbocyanine iodide (DiI[5]) in intact normal human erythrocytes is D = 8.2 +/- 1.2 X 10(-9) cm2/s at 25 degrees C and D = 2.1 +/- 0.4 X 10(-8) cm2/s at 37 degrees C, and varies approximately 50-fold between 1 degree and 42 degrees C. The diffusion constants of lipid analogue rhodamine-B phosphatidylethanolamine (RBPE) are about twice those of DiI[5]. The temperature dependence and magnitude of D vary by up to a factor of 3 between species and are only influenced by donor age in prenatals. DiI[5] diffusibility is not perturbed by the presence of calcium or local anesthetics or by spectrin depletion (via mutation). However, lipid-analogue diffusibility in erythrocyte ghosts may differ from intact cells. Dietary hypercholesterolemia in rabbits reduces the diffusion coefficient and eliminates the characteristic break in Arrhenius plots of D found in all other cells studied except frog. PMID:6603237

  20. HYDROCARBON VAPOR DIFFUSION IN INTACT CORE SLEEVES

    EPA Science Inventory

    The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors out of residually contaminated sandy soil from the U.S. Environmental Protection Agency (EPA) field research site at Traverse City, Michigan, was measured and modeled. he headspace of an intact c...

  1. HYDROCARBON VAPOR DIFFUSION IN INTACT CORE SLEEVES

    EPA Science Inventory

    The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors put of residually contaminated sandy soil from the U.S. Environmental Protection Agency (EPA) field research site at Traverse City, Michigan, was measured and modeled. The headspace of an intact ...

  2. Plant growth and the performance of mangrove wetland microcosms for mariculture effluent depuration.

    PubMed

    Su, Yung-Ming; Lin, Ying-Feng; Jing, Shuh-Ren; Hou, Ping-Chun Lucy

    2011-07-01

    This study established wetland microcosms that were either unplanted or planted in monoculture with native mangrove species in Taiwan (Avicennia marina, Rhizophora stylosa, and Lumnitzera racemosa) for the purpose of receiving high-salinity mariculture effluents; additionally, the microcosms operated at different hydraulic retention times (HRTs). Plant growth and the performance of the microcosms with respect to pollutant removal were investigated. The results showed that seedlings of all three mangrove species survived and grew sufficiently well under continuous flooding. The presence of mangroves consistently improved SS, BOD(5), and TP removal, particularly under short HRT conditions. The mangrove microcosms removed pollutants from the mariculture effluents with efficiencies of 5.7-27.1% (SS), 4.9-36.3% (BOD(5)), 18.7-29.9% (TP), 21.2-49.8% (NH(4)-N), and 5.4-37.7% (NO(x)-N). A. marina and L. racemosa were more tolerant of continuous flooding than R. stylosa. However, no species displayed consistently superior performance in decreasing all pollutant-related parameters investigated. For all pollutants, microcosms operating at a 2-d HRT exhibited a higher removal efficiency than those operating at a 0.5-d HRT. PMID:21561629

  3. Automated online measurement of N2, N2O, NO, CO2, and CH4 emissions based on a gas-flow-soil-core technique.

    PubMed

    Liao, Tingting; Wang, Rui; Zheng, Xunhua; Sun, Yang; Butterbach-Bahl, Klaus; Chen, Nuo

    2013-11-01

    The gas-flow-soil-core (GFSC) technique allows to directly measure emission rates of denitrification gases of incubated soil cores. However, the technique was still suffering some drawbacks such as inadequate accuracy due to asynchronous detection of dinitrogen (N2) and other gases and low measurement frequency. Furthermore, its application was limited due to intensive manual operation. To overcome these drawbacks, we updated the GFSC system as described by Wang et al. (2011) by (a) using both a chemiluminescent detector and a gas chromatograph detector to measure nitric oxide (NO), (b) synchronizing the measurements of N2, NO, nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4), and (c) fully automating the sampling/analysis of all the gases. These technical modifications significantly reduced labor demands by at least a factor of two, increased the measurement frequency from 3 to 6 times per day and resulted in remarkable improvements in measurement accuracy (with detection limits of 0.5, 0.01, 0.05, 2.3 and 0.2μgN or Ch(-1)kg(-1)ds, or 17, 0.3, 1.8, 82, and 6μgN or Cm(-2)h(-1), for N2, N2O, NO, CO2, and CH4, respectively). In some circumstances, the modified system measured significantly more N2 and CO2 and less N2O and NO because of the enhanced measurement frequency. The modified system distinguished the differences in emissions of the denitrification gases and CO2 due to a 20% change in initial carbon supplies. It also remarkably recovered approximately 90% of consumed nitrate during incubation. These performances validate the technical improvement, and indicate that the improved GFSC system may provide a powerful research tool for obtaining deeper insights into the processes of soil carbon and nitrogen transformation during denitrification. PMID:24184044

  4. Non-destructive Analysis of Oil-Contaminated Soil Core Samples by X-ray Computed Tomography and Low-Field Nuclear Magnetic Resonance Relaxometry: a Case Study

    PubMed Central

    Mitsuhata, Yuji; Nishiwaki, Junko; Kawabe, Yoshishige; Utsuzawa, Shin; Jinguuji, Motoharu

    2010-01-01

    Non-destructive measurements of contaminated soil core samples are desirable prior to destructive measurements because they allow obtaining gross information from the core samples without touching harmful chemical species. Medical X-ray computed tomography (CT) and time-domain low-field nuclear magnetic resonance (NMR) relaxometry were applied to non-destructive measurements of sandy soil core samples from a real site contaminated with heavy oil. The medical CT visualized the spatial distribution of the bulk density averaged over the voxel of 0.31 × 0.31 × 2 mm3. The obtained CT images clearly showed an increase in the bulk density with increasing depth. Coupled analysis with in situ time-domain reflectometry logging suggests that this increase is derived from an increase in the water volume fraction of soils with depth (i.e., unsaturated to saturated transition). This was confirmed by supplementary analysis using high-resolution micro-focus X-ray CT at a resolution of ∼10 μm, which directly imaged the increase in pore water with depth. NMR transverse relaxation waveforms of protons were acquired non-destructively at 2.7 MHz by the Carr–Purcell–Meiboom–Gill (CPMG) pulse sequence. The nature of viscous petroleum molecules having short transverse relaxation times (T2) compared to water molecules enabled us to distinguish the water-saturated portion from the oil-contaminated portion in the core sample using an M0–T2 plot, where M0 is the initial amplitude of the CPMG signal. The present study demonstrates that non-destructive core measurements by medical X-ray CT and low-field NMR provide information on the groundwater saturation level and oil-contaminated intervals, which is useful for constructing an adequate plan for subsequent destructive laboratory measurements of cores. PMID:21258437

  5. Small Particles Intact Capture Experiment (SPICE)

    NASA Astrophysics Data System (ADS)

    Nishioka, Ken-Ji; Carle, G. C.; Bunch, T. E.; Mendez, David J.; Ryder, J. T.

    The Small Particles Intact Capture Experiment (SPICE) will develop technologies and engineering techniques necessary to capture nearly intact, uncontaminated cosmic and interplanetary dust particles (IDP's). Successful capture of such particles will benefit the exobiology and planetary science communities by providing particulate samples that may have survived unaltered since the formation of the solar system. Characterization of these particles may contribute fundamental data to our knowledge of how these particles could have formed into our planet Earth and, perhaps, contributed to the beginnings of life. The term 'uncontaminated' means that captured cosmic and IDP particles are free of organic contamination from the capture process and the term 'nearly intact capture' means that their chemical and elemental components are not materially altered during capture. The key to capturing cosmic and IDP particles that are organic-contamination free and nearly intact is the capture medium. Initial screening of capture media included organic foams, multiple thin foil layers, and aerogel (a silica gel); but, with the exception of aerogel, the requirements of no contamination or nearly intact capture were not met. To ensure no contamination of particles in the capture process, high-purity aerogel was chosen. High-purity aerogel results in high clarity (visual clearness), a useful quality in detection and recovery of embedded captured particles from the aerogel. P. Tsou at the Jet Propulsion Laboratory (JPL) originally described the use of aerogel for this purpose and reported laboratory test results. He has flown aerogel as a 'GAS-can Lid' payload on STS-47 and is evaluating the results. The Timeband Capture Cell Experiment (TICCE), a Eureca 1 experiment, is also flying aerogel and is scheduled for recovery in late April.

  6. Small Particles Intact Capture Experiment (SPICE)

    NASA Technical Reports Server (NTRS)

    Nishioka, Ken-Ji; Carle, G. C.; Bunch, T. E.; Mendez, David J.; Ryder, J. T.

    1994-01-01

    The Small Particles Intact Capture Experiment (SPICE) will develop technologies and engineering techniques necessary to capture nearly intact, uncontaminated cosmic and interplanetary dust particles (IDP's). Successful capture of such particles will benefit the exobiology and planetary science communities by providing particulate samples that may have survived unaltered since the formation of the solar system. Characterization of these particles may contribute fundamental data to our knowledge of how these particles could have formed into our planet Earth and, perhaps, contributed to the beginnings of life. The term 'uncontaminated' means that captured cosmic and IDP particles are free of organic contamination from the capture process and the term 'nearly intact capture' means that their chemical and elemental components are not materially altered during capture. The key to capturing cosmic and IDP particles that are organic-contamination free and nearly intact is the capture medium. Initial screening of capture media included organic foams, multiple thin foil layers, and aerogel (a silica gel); but, with the exception of aerogel, the requirements of no contamination or nearly intact capture were not met. To ensure no contamination of particles in the capture process, high-purity aerogel was chosen. High-purity aerogel results in high clarity (visual clearness), a useful quality in detection and recovery of embedded captured particles from the aerogel. P. Tsou at the Jet Propulsion Laboratory (JPL) originally described the use of aerogel for this purpose and reported laboratory test results. He has flown aerogel as a 'GAS-can Lid' payload on STS-47 and is evaluating the results. The Timeband Capture Cell Experiment (TICCE), a Eureca 1 experiment, is also flying aerogel and is scheduled for recovery in late April.

  7. The influence of iron on the biodegradation of benzene in soil microcosms

    SciTech Connect

    Poor, N.D.; Wheeler, E.; Novak, J.T.

    1996-12-31

    Iron was positively-correlated with benzene biodegradation rate in a statistically-significant multiple linear regression model of rates measured in aerobic soil microcosm experiments regressed with corresponding soil nitrate, phosphorus, iron, organic matter and sand content for 10 different previously uncontaminated Virginia subsurface soils. The addition of ferric chloride or ferric hydroxide to soil microcosms prepared with Alaga series sand and spiked with 10 mg/L initial benzene significantly increased the biodegradation rate in unamended experiments, but had no observable influence on biodegradation rates in experiments amended with ammonium phosphate and potassium phosphate. Unamended soil microcosms degraded 10 mg/L initial benzene in 10 days, iron-amended in 5 days, and nutrient-amended in 2 days.

  8. Quick stimulation of Alcanivorax sp. by bioemulsificant EPS2003 on microcosm oil spill simulation

    PubMed Central

    Cappello, Simone; Genovese, Maria; Denaro, Renata; Santisi, Santina; Volta, Anna; Bonsignore, Martina; Mancini, Giuseppe; Giuliano, Laura; Genovese, Lucrezia; Yakimov, Michail M.

    2014-01-01

    Oil spill microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS2003) on quick stimulation of hydrocarbonoclastic bacteria. Early hours of oil spill, were stimulated using an experimental seawater microcosm, supplemented with crude oil and EPS2003 (SW+OIL+EPS2003); this system was monitored for 2 days and compared to control microcosm (only oil-polluted seawater, SW+OIL). Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out. Community composition of marine bacterioplankton was determined by 16S rRNA gene clone libraries. Data obtained indicated that bioemulsificant addition stimulated an increase of total bacterial abundance and, in particular, selection of bacteria related to Alcanivorax genus; confirming that EPS2003 could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process. PMID:25763036

  9. Fungal diversity and ecosystem function data from wine fermentation vats and microcosms.

    PubMed

    Boynton, Primrose J; Greig, Duncan

    2016-09-01

    Grape must is the precursor to wine, and consists of grape juice and its resident microbial community. We used Illumina MiSeq® to track changes in must fungal community composition over time in winery vats and laboratory microcosms. We also measured glucose consumption and biomass in microcosms derived directly from must, and glucose consumption in artificially assembled microcosms. Functional impacts of individual must yeasts in artificially assembled communities were calculated using a "keystone index," developed for "Species richness influences wine ecosystem function through a dominant species" [1]. Community composition data and functional measurements are included in this article. DNA sequences were deposited in GenBank (GenBank: SRP073276). Discussion of must succession and ecosystem functioning in must are provided in [1]. PMID:27331092

  10. MICROCOSM AND IN-SITU FIELD STUDIES OF ENHANCED BIOTRANSFORMATION OF TRICHLOROETHYLENE BY PHENOL-UTILIZING MICROORGANISMS

    EPA Science Inventory

    The ability of different aerobic groundwater microorganisms to cometabolically degrade trichloroethylene (TCE), 1,2-cis-dichloroethylene (c-DCE), and 1,2-trans-dichloroethylene (t-DCE) was evaluated both in groundwater-fed microcosms and in situ in a shallow aquifer. Microcosms a...

  11. The Use of Microcosms as an Experimental Approach to Understanding Terrestrial Ecosystem Functioning

    NASA Astrophysics Data System (ADS)

    Fraser, L. H.

    1999-01-01

    Since 1986, a series of microcosm experiments has been conducted at the Unit of Comparative Plant Ecology (UCPE) in an attempt to test our understanding of the principles controlling the structure and dynamics of plant communities and ecosystems. In each experiment microcosms have been seeded with a common pool of organisms, and systems have been allowed to assemble under replicated controlled conditions. Experiment variables have included mineral nutrient supply, temperature, moisture supply, soil depth, carbon dioxide concentration, mycorrhizas, rhizobia, herbivores and carnivores. Results from these experiments are presented to illustrate the value of synthesised ecosystems in ecological research.

  12. Stimulation of Mercury Methylation by Coal Ash in Anaerobic Sediment Microcosms

    NASA Astrophysics Data System (ADS)

    Schwartz, G.; Hsu-Kim, H.; Redfern, L.; Gunsch, C.; Vengosh, A.

    2015-12-01

    Coal combustion products (coal ash) represent one of the largest industrial waste streams in the United States. Coal ash contains elevated levels of toxic, bioaccumulative elements such as mercury (Hg), yet the majority of coal ash waste is stored in unlined impoundments and landfills. These impoundments have a long history of environmental degradation, including: groundwater contamination, surface water contamination through impoundment effluent discharge, and impoundment failures resulting in catastrophic ash release events. The fate of toxic elements associated with coal ash is greatly influenced by environmental parameters, such as redox potential and microbial activity, which induce transformations and leaching of contaminants. Here we used anaerobic sediment-ash microcosms to determine how coal ash impacts methyl mercury (MeHg) production in a simulated benthic aquatic environment. We used two coal ash types in the microcosms: a weathered ash with low sulfate/Hg content and a fresh fly ash that was relatively enriched in sulfate/Hg compared to the weathered ash. Two different sediments were used in the microcosms: one was a pristine sediment (containing 0.03 mg/kg Hg) and the other was a relatively Hg-contaminated sediment (containing 0.29 mg/kg Hg). Results showed that microcosms amended with the low sulfate/low Hg ash had no net MeHg production. In contrast, microcosms amended with high sulfate/high Hg ash showed increases in MeHg concentrations that were 2 to 3 times greater than control microcosms without ash, indicating that coal ash can stimulate MeHg production by providing spikes of Hg and labile sulfate to the aquatic system. MeHg production in ash-amended microcosms containing contaminated sediment was no greater than in the ash-amended pristine sediment microcosms. This may indicate that Hg associated with coal ash is more bioavailable than the Hg present in historically contaminated sediments. Illumina sequencing is underway to investigate the

  13. Xenopus egg cytoplasm with intact actin.

    PubMed

    Field, Christine M; Nguyen, Phuong A; Ishihara, Keisuke; Groen, Aaron C; Mitchison, Timothy J

    2014-01-01

    We report optimized methods for preparing Xenopus egg extracts without cytochalasin D, that we term "actin-intact egg extract." These are undiluted egg cytoplasm that contains abundant organelles, and glycogen which supplies energy, and represents the least perturbed cell-free cytoplasm preparation we know of. We used this system to probe cell cycle regulation of actin and myosin-II dynamics (Field et al., 2011), and to reconstitute the large, interphase asters that organize early Xenopus embryos (Mitchison et al., 2012; Wühr, Tan, Parker, Detrich, & Mitchison, 2010). Actin-intact Xenopus egg extracts are useful for analysis of actin dynamics, and interaction of actin with other cytoplasmic systems, in a cell-free system that closely mimics egg physiology, and more generally for probing the biochemistry and biophysics of the egg, zygote, and early embryo. Detailed protocols are provided along with assays used to check cell cycle state and tips for handling and storing undiluted egg extracts. PMID:24630119

  14. Silica Aerogel Captures Cosmic Dust Intact

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1994-01-01

    The mesostructure of silica aerogel resembles stings of grapes, ranging in size from 10 to 100 angstrom. This fine mesostructure transmits nearly 90 percent of incident light in the visible, while providing sufficiently gentle dissipation of the kinetric energy of hypervelocity cosmic dust particles to permit their intact capture. We introduced silica aerogel in 1987 as capture medium to take advantage of its low density, fine mesostruicture and most importantly, its transparency, allowing optical location of captured micron sized particles.

  15. Measuring mitochondrial function in intact cardiac myocytes

    PubMed Central

    Dedkova, Elena N.; Blatter, Lothar A.

    2011-01-01

    Mitochondria are involved in cellular functions that go beyond the traditional role of these organelles as the power plants of the cell. Mitochondria have been implicated in several human diseases, including cardiac dysfunction, and play a role in the aging process. Many aspects of our knowledge of mitochondria stem from studies performed on the isolated organelle. Their relative inaccessibility imposes experimental difficulties to study mitochondria in their natural environment – the cytosol of intact cells – and has hampered a comprehensive understanding of the plethora of mitochondrial functions. Here we review currently available methods to study mitochondrial function in intact cardiomyocytes. These methods primarily use different flavors of fluorescent dyes and genetically encoded fluorescent proteins in conjunction with high-resolution imaging techniques. We review methods to study mitochondrial morphology, mitochondrial membrane potential, Ca2+ and Na+ signaling, mitochondrial pH regulation, redox state and ROS production, NO signaling, oxygen consumption, ATP generation and the activity of the mitochondrial permeability transition pore. Where appropriate we complement this review on intact myocytes with seminal studies that were performed on isolated mitochondria, permeabilized cells, and in whole hearts. PMID:21964191

  16. Multi-View Intact Space Learning.

    PubMed

    Xu, Chang; Tao, Dacheng; Xu, Chao

    2015-12-01

    It is practical to assume that an individual view is unlikely to be sufficient for effective multi-view learning. Therefore, integration of multi-view information is both valuable and necessary. In this paper, we propose the Multi-view Intact Space Learning (MISL) algorithm, which integrates the encoded complementary information in multiple views to discover a latent intact representation of the data. Even though each view on its own is insufficient, we show theoretically that by combing multiple views we can obtain abundant information for latent intact space learning. Employing the Cauchy loss (a technique used in statistical learning) as the error measurement strengthens robustness to outliers. We propose a new definition of multi-view stability and then derive the generalization error bound based on multi-view stability and Rademacher complexity, and show that the complementarity between multiple views is beneficial for the stability and generalization. MISL is efficiently optimized using a novel Iteratively Reweight Residuals (IRR) technique, whose convergence is theoretically analyzed. Experiments on synthetic data and real-world datasets demonstrate that MISL is an effective and promising algorithm for practical applications. PMID:26539856

  17. Radioimmunoassay for intact Gross mouse leukemia virus.

    PubMed Central

    Yalow, R S; Gross, L

    1976-01-01

    A radioimmunoassay for intact Gross leukemia virus has been developed using 125I-labeled Gross virus grown in tissue culture and guinea pig antisera to Gross virus grown either in tissue culture or harvested from leukemic C3H(f) mice. Separation of bound from free labeled virus was effected using the double antibody method. The assay can detect fewer than 10(8) virus particles and has been used to measure the viral content of individual organs from inoculated leukemic C3H(f) mice and from Ak mice with spontaneous leukemia. Organs from noninoculated healthy C3H(f) mice crossreacted poorly in the system, virus generally being detectable only in the thymus and spleen and at low concentration. In some of the inoculated C3H(f) leukemic mice the viral content of as little as 0.5 mul of plasma is measurable. That this assay is for intact virus and not for soluble antigens of the viral envelope was proven by the observation that the immunoreactive material of plasma and extracts from thymus and liver of leukemic mice has a buoyant denisty in sucrose of 1.17-1.18 g/ml, corresponding to that of intact virus grown in tissue culture. With this sensitivity it may now be possible to quantitate viral concentrations in tissue and body fluids from the time of inoculation through the development of obvious pathology. PMID:1066697

  18. IMPORTANCE OF PHYSICAL SCALING FACTORS TO BENTHIC MARINE INVERTEBRATE RECOLONIZATION OF LABORATORY MICROCOSMS

    EPA Science Inventory

    Five laboratory studies of benthic macroinvertebrate recolonization were conducted for 6-wk periods to evaluate the effects of physical factors (i.e., microcosm size, seawater flow rates and sediment depth) on benthic community structure. esign variables included4 open-faced acry...

  19. STIMULATION OF THE REDUCTIVE DECHLORINATION OF TETRACHLOROETHENE IN ANAEROBIC AQUIFER MICROCOSMS BY THE ADDITION OF TOLUENE

    EPA Science Inventory

    In this study, the biologically mediated interactions of toluene and PCE under anaerobic conditions were investigated by using microcosms constructed with aquifer solids from an area that was exposed to both alkylbenzenes and chlorinated ethenes at the U.S. Coast Guard Air Statio...

  20. Effects Of Nutrient Source And Supply On Crude Oil Biodegradation In Continuous-Flow Beach Microcosms

    EPA Science Inventory

    Ammonium and nitrate were used as nitrogen sources to support microbial biodegradation of crude oil in continuous-flow beach microcosms to determine whether either nutrient was more effective in open systems, such as intertidal shorelines. No differences in the rate or the exten...

  1. Methanogenic degradation kinetics of phenolic compounds in aquifer-derived microcosms

    USGS Publications Warehouse

    Godsy, E.M.; Goerlitz, D.F.; Grbic-Galic, D.

    1992-01-01

    In this segment of a larger multidisciplinary study of the movement and fate of creosote derived compounds in a sand-and-gravel aquifer, we present evidence that the methanogenic degradation of the major biodegradable phenolic compounds and concomitant microbial growth in batch microcosms derived from contaminated aquifer material can be described using Monod kinetics. Substrate depletion and bacterial growth curves were fitted to the Monod equations using nonlinear regression analysis. The method of Marquardt was used for the determination of parameter values that best fit the experimental data by minimizing the residual sum of squares. The Monod kinetic constants (??max, Ks, Y, and kd) that describe phenol, 2-, 3-, and 4-methylphenol degradation and concomitant microbial growth were determined under conditions that were substantially different from those previously reported for microcosms cultured from sewage sludge. The Ks values obtained in this study are approximately two orders of magnitude lower than values obtained for the anaerobic degradation of phenol in digesting sewage sludge, indicating that the aquifer microorganisms have developed enzyme systems that are adapted to low nutrient conditions. The values for kd are much less than ??max, and can be neglected in the microcosms. The extremely low Y values, approximately 3 orders of magnitude lower than for the sewage sludge derived cultures, and the very low numbers of microorganisms in the aquifer derived microcosms suggest that these organisms use some unique strategies to survive in the subsurface environment. ?? 1992 Kluwer Academic Publishers.

  2. INFLUENCE OF SOLID SURFACE, ADHESIVE ABILITY, AND INOCULUM SIZE ON BACTERIAL COLONIZATION IN MICROCOSM STUDIES

    EPA Science Inventory

    Microcosm studies were performed to evaluate the effect of solid surfaces, bacterial adhesive ability, and inoculum size on colonization success and persistence of P. fluorescens or X maltophilia, each with a Tn5 insertion that conferred resistance to kanamycin and streptomycin. ...

  3. Creating a Community. A Microcosm that Develops Career Awareness. Career Development Program.

    ERIC Educational Resources Information Center

    Winograd, Myra

    Intended for use by teachers in elementary and junior high schools, this booklet offers ten classroom activities to create a community microcosm which would enable students to develop awareness of career opportunities and of community values and priorities. As a lead-in exercise, lesson 1 suggests two films for the class to view and discuss.…

  4. EFFECTS OF MICROCOSM PREPARATION ON RATES OF TOLUENE BIODEGRADATION UNDER DENITRIFYING CONDITIONS

    EPA Science Inventory

    Microcosms were prepared with subsurface material from two aquifers to examine the effects of preparation methods on rates of toluene biodegradation under denitrifying conditions. In both cases, the data fit a zero-order kinetics plot. However, rates of removal were generally pro...

  5. LONG-TERM SURVIVAL AND PLASMID MAINTENANCE OF ESCHERICHIA COLI IN MARINE MICROCOSMS

    EPA Science Inventory

    The survival pattern and plasmid maintenance of Escherichia con was examined in an artificial seawater microcosm. t was found that the three strain, of E. coli (EK3C, H10407 and 34309) included in the study were able to maintain a portion of cells in the culturable phase for at l...

  6. Enrichment of anaerobic benzene-degrading microorganisms by in situ microcosms.

    PubMed

    Herrmann, Steffi; Kleinsteuber, Sabine; Neu, Thomas R; Richnow, Hans Hermann; Vogt, Carsten

    2008-01-01

    Microcosms filled with different solids (sand, lava, Amberlite XAD-7) were exposed for 67 days in the sulfidic part of a groundwater monitoring well downstream of the source zone of a benzene-contaminated aquifer and subsequently incubated in the laboratory. Benzene was repeatedly degraded in several microcosms accompanied by production of sulfide, leading to stable benzene-degrading enrichment cultures. In control microcosms without filling material, benzene was initially degraded, but the benzene-degrading capacity could not be sustained. The results indicate that long-term physiologically active benzene-degrading microorganisms were attached to surfaces of the solids. The biodiversity and attachment behavior of microorganisms in the in situ microcosms was assessed by confocal laser scanning microscopy and single-strand conformation polymorphism (SSCP) analysis, followed by sequencing of dominant SSCP bands. The microbial community was composed of several different Bacteria, representing members of Clostridia, Bacteroidales, all subgroups of the Proteobacteria, Verrucomicrobia, Nitrospira, Chloroflexi and Chlorobi. Only a few archaeal sequences could be retrieved from the communities. The majority of phylotypes were affiliated to bacterial groups with a possible functional relationship to the bacterial sulfur cycle, thus indicating that the microbial community in the investigated aquifer zone depends mainly on inorganic sulfur compounds as electron donors or acceptors, a finding that corresponds to the geochemical data. PMID:18081593

  7. MICROCOSM FOR MEASURING SURVIVAL AND CONJUGATION OF GENETICALLY ENGINEERED BACTERIA IN RHIZOSPHERE ENVIRONMENTS

    EPA Science Inventory

    A microcosm is described to evaluate and measure bacterial conjugation in the rhizosphere of barley and radish with strains of Pseudomonas cepacia. he purpose was to describe a standard method useful for evaluating the propensity of genetically engineered microorganisms (GEMs) to...

  8. AEROBIC SOIL MICROCOSMS FOR LONG-TERM BIODEGRADATION OF HYDROCARBON VAPORS

    EPA Science Inventory

    The aims of this research project included the development of laboratory protocols for the preparation of aerobic soil microcosms using aseptic field soil samples, and for the gas chromatographic analysis of hydrocarbon vapor biodegradation based on vapor samples obtained from th...

  9. CONJUGAL TRANSFER AT NATURAL POPULATION DENSITIES IN A MICROCOSM SIMULATING AN ESTUARINE ENVIRONMENT

    EPA Science Inventory

    Estuarine microcosms were used to follow conjugal transfer of a broad host range IncP1 plasmid from a Pseudomonas putida donor to indigenous bacteria. onor cells were added at a concentration similar to the natural abundance of bacteria in the water column (10 6/mi). ransfer was ...

  10. Enumeration and Biomass Estimation of Bacteria in Aquifer Microcosm Studies by Flow Cytometry

    PubMed Central

    DeLeo, P. C.; Baveye, P.

    1996-01-01

    Flow cytometry was used to enumerate and characterize bacteria from a sand column microcosm simulating aquifer conditions. Pure cultures of a species of Bacillus isolated from subsurface sediments or Bacillus megaterium were first evaluated to identify these organisms' characteristic histograms. Counting was then carried out with samples from the aquifer microcosms. Enumeration by flow cytometry was compared with more-traditional acridine orange direct counting. These two techniques gave statistically similar results. However, counting by flow cytometry, in this case, surveyed a sample size 700 times greater than did acridine orange direct counting (25 (mu)l versus 0.034 (mu)l) and required 1/10 the time (2 h versus 20 h). Flow cytometry was able to distinguish the same species of bacteria grown under different nutrient conditions, and it could distinguish changes in cell growth patterns, specifically single cell growth versus chained cell growth in different regions of an aquifer microcosm. A biomass estimate was calculated by calibrating the total fluorescence of a sample from a pure culture with the dry weight of a freeze-dried volume from the original pure culture. Growth conditions significantly affected histograms and biomass estimates, so the calibration was carried out with cells grown under conditions similar to those in the aquifer microcosm. Costs associated with using flow cytometry were minimal compared with the amount of time saved in counting cells and estimating biomass. PMID:16535470

  11. EPA worst case water microcosms for testing phage biocontrol of Salmonella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method using laboratory microcosms is proposed for evaluating the effectiveness of selected phages for biocontrol of Salmonella within swine effluent and manure impacted environments. The method uses EPA (U.S. Environmental Protection Agency) worst case water as a high organic matter matrix to s...

  12. EFFECTS OF FLUORENE ON MICROCOSMS DEVELOPED FROM FOUR NATURAL COMMUNITIES (JOURNAL VERSION)

    EPA Science Inventory

    Ecosystem-level responses were examined in microcosms developed from four different natural plankton communities and exposed to nominal concentrations of 0.12, 0.50, 2.0, 5.0 and 10.0 mg/L fluorene. The lowest observed effect level (LOEL) for dark respiration was 0.12 mg/L fluore...

  13. ADAPTATION OF MIXED FLASK CULTURE MICROCOSMS FOR TESTING THE SURVIVAL AND EFFECTS OF INTRODUCED MICROORGANISMS

    EPA Science Inventory

    A microcosm test was used to evaluate the survival and effects of Bacillus thuringiensis var. israelinsis (Bti) in aquatic systems. wo commercial formulations (Vectobac tm from Abbot; Mosquito Attack tm form Aeuters Laboratories) and a laboratory preparation of Bti spores were te...

  14. Effect of isobutanol on toluene biodegradation in nitrate amended, sulfate amended and methanogenic enrichment microcosms.

    PubMed

    Jayamani, Indumathy; Cupples, Alison M

    2013-09-01

    Isobutanol is an alternate fuel additive that is being considered because of economic and lower emission benefits. However, future gasoline spills could result in co-contamination of isobutanol with gasoline components such as benzene, toluene, ethyl-benzene and xylene. Hence, isobutanol could affect the degradability of gasoline components thereby having an effect on contaminant plume length and half-life. In this study, the effect of isobutanol on the biodegradation of a model gasoline component (toluene) was examined in laboratory microcosms. For this, toluene and isobutanol were added to six different toluene degrading laboratory microcosms under sulfate amended, nitrate amended or methanogenic conditions. While toluene biodegradation was not greatly affected in the presence of isobutanol in five out of the six different experimental sets, toluene degradation was completely inhibited in one set of microcosms. This inhibition occurred in sulfate amended microcosms constructed with inocula from wastewater treatment plant activated sludge. Our data suggest that toluene degrading consortia are affected differently by isobutanol addition. These results indicate that, if co-contamination occurs, in some cases the in situ half-life of toluene could be significantly extended. PMID:23224907

  15. Pyrosequencing Analysis Reveals High Population Dynamics of the Soil Microcosm Degrading Octachlorodibenzofuran

    PubMed Central

    Chen, Wei-Yu; Wu, Jer-Horng; Chang, Juu-En

    2014-01-01

    A deeper understanding of the microbial community structure is very important in bioremediation for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs). However, this has been insufficiently addressed in previous studies. To obtain more information, we pyrosequenced the V4/V5 regions of the 16S rRNA genes of bacterial communities transited from polluted soil to batch microcosms that rapidly degraded high concentrations of octachlorodibenzofuran (OCDF). The analysis results contained an average of 11,842 reads per sample, providing the first detailed description of bacterial communities associated with PCDD/Fs. The community composition markedly changed to be concomitant with the degradation of OCDF, indicating that a distinctive population structure developed rapidly in the microcosm. Although oxygen gas was provided weekly to the microcosm, the growth of potential degraders, Sphingomonas, Pseudomonas, Rhodococcus, and Clostridium, was observed, but in consistently low quantities. While anaerobic Sedimentibacter initially emerged as an abundant pioneer, several aerobic participants, such as the genera Brevundimonas, Pseudoxanthomonas, and Lysobacter, exhibited a large increase in their 16S rRNA gene copies within the timeframe, which showed a temporal population dynamic, and indicated their collaborative contributions to the degradation of OCDF under hypoxic conditions. These results have provided a deeper insight into the microbial community structure and population dynamics of the OCDF-degrading microcosm. PMID:25491754

  16. Fate of Sulfamethazine in Surface Water Microcosms and Bioaccumulation in Sediment-dwelling Invertebrates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antibiotic sulfamethazine can be transported from manured fields to surface water bodies. We investigated the degradation and fate of sulfamethazine in small pond water microcosms using 14C-phenyl-sulfamethazine, and found a 2.7-d half-life in pond water and 4.2-d half-life when added to the wat...

  17. ENANTIOSELECTIVE REDUCTIVE TRANSFORMATION OF CHIRAL POLYCHLORINATED BIPHENYLS IN LAKE SEDIMENT MICROCOSMS

    EPA Science Inventory

    The transformation rates and enantiomeric ratios of two chiral poylchlorinated biphenyls (PCBs), 2,2',3,4',5',6-hexachlorobiphenyl (2,2',3,4',5',6-HCB) and 2,2',3,3',4,4',5,6-octachlorobiphenyl (2,2',3,3',4,4',5,6-OCB), were determined in anaerobic lake sediment microcosms (25oC)...

  18. SURVIVAL OF SALMONELLA TYPHIMURIUM IN FOUR SOIL MICROCOSMS AS AFFECTED BY SOIL TYPE AND INCUBATION TEMPERATURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Survival of Salmonella typhimurium was determined in sterile and non-sterile microcosms in four soil series (Brooksville, Leeper, Marietta, and Ruston) held at 10, 15, 25 and 35 degrees C. Exponential linear destruction was observed for S. typhimurium in non-sterile soil stored at all temperatures....

  19. The Institution of Carlisle School: A Microcosm of 500 Years of Indian Policy.

    ERIC Educational Resources Information Center

    Fine, Mike

    The history of the Carlisle Indian Boarding School is a microcosm of 500 years of Indian policy. Established through the efforts of career military man Richard Pratt in 1879, the school symbolized the emerging view of assimilation, an important change from earlier attempts at genocide and prior militant attitudes towards the Indians. Long…

  20. Calcium Signaling in Intact Dorsal Root Ganglia

    PubMed Central

    Gemes, Geza; Rigaud, Marcel; Koopmeiners, Andrew S.; Poroli, Mark J.; Zoga, Vasiliki; Hogan, Quinn H.

    2013-01-01

    Background Ca2+ is the dominant second messenger in primary sensory neurons. In addition, disrupted Ca2+ signaling is a prominent feature in pain models involving peripheral nerve injury. Standard cytoplasmic Ca2+ recording techniques use high K+ or field stimulation and dissociated neurons. To compare findings in intact dorsal root ganglia, we used a method of simultaneous electrophysiologic and microfluorimetric recording. Methods Dissociated neurons were loaded by bath-applied Fura-2-AM and subjected to field stimulation. Alternatively, we adapted a technique in which neuronal somata of intact ganglia were loaded with Fura-2 through an intracellular microelectrode that provided simultaneous membrane potential recording during activation by action potentials (APs) conducted from attached dorsal roots. Results Field stimulation at levels necessary to activate neurons generated bath pH changes through electrolysis and failed to predictably drive neurons with AP trains. In the intact ganglion technique, single APs produced measurable Ca2+ transients that were fourfold larger in presumed nociceptive C-type neurons than in nonnociceptive Aβ-type neurons. Unitary Ca2+ transients summated during AP trains, forming transients with amplitudes that were highly dependent on stimulation frequency. Each neuron was tuned to a preferred frequency at which transient amplitude was maximal. Transients predominantly exhibited monoexponential recovery and had sustained plateaus during recovery only with trains of more than 100 APs. Nerve injury decreased Ca2+ transients in C-type neurons, but increased transients in Aβ-type neurons. Conclusions Refined observation of Ca2+ signaling is possible through natural activation by conducted APs in undissociated sensory neurons and reveals features distinct to neuronal types and injury state. PMID:20526180

  1. High frequency oscillations in the intact brain

    PubMed Central

    Buzsáki, György; da Silva, Fernando Lopes

    2016-01-01

    High frequency oscillations (HFOs) constitute a novel trend in neurophysiology that is fascinating neuroscientists in general, and epileptologists in particular. But what are HFOs? What is the frequency range of HFOs? Are there different types of HFOs, physiological and pathological? How are HFOs generated? Can HFOs represent temporal codes for cognitive processes? These questions are pressing and this symposium volume attempts to give constructive answers. As a prelude to this exciting discussion, we summarize the physiological high frequency patterns in the intact brain, concentrating mainly on hippocampal patterns, where the mechanisms of high frequency oscillations are perhaps best understood. PMID:22449727

  2. Phylogenetic Characterization of a Polychlorinated-Dioxin- Dechlorinating Microbial Community by Use of Microcosm Studies

    PubMed Central

    Yoshida, Naoko; Takahashi, Nobutaka; Hiraishi, Akira

    2005-01-01

    Microcosms capable of reductive dechlorination of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) were constructed in glass bottles by seeding them with a polluted river sediment and incubating them anaerobically with an organic medium. All of the PCDD/F congeners detected were equally reduced without the accumulation of significant amounts of less-chlorinated congeners as the intermediate or end products. Alternatively, large amounts of catechol and salicylic acid were produced in the upper aqueous phase. Thus, the dechlorination of PCDD/Fs and the oxidative degradation of the dechlorinated products seemed to take place simultaneously in the microcosm. Denaturing gel gradient electrophoresis and clone library analyses of PCR-amplified 16S rRNA genes from the microcosm showed that members of the phyla Firmicutes, Proteobacteria, and Bacteroidetes predominated. A significant number of Chloroflexi clones were also detected. Quantitative real-time PCR with specific primer sets showed that the 16S rRNA genes of a putative dechlorinator, “Dehalococcoides,” and its relatives accounted for 0.1% of the total rRNA gene copies of the microcosm. Most of the clones thus obtained formed a cluster distinct from the typical “Dehalococcoides” group. Quinone profiling indicated that ubiquinones accounted for 18 to 25% of the total quinone content, suggesting the coexistence and activity of ubiquinone-containing aerobic bacteria. These results suggest that the apparent complete dechlorination of PCDD/Fs found in the microcosm was due to a combination of the dechlorinating activity of the “Dehalococcoides”-like organisms and the oxidative degradation of the dechlorinated products by aerobic bacteria with aromatic hydrocarbon dioxygenases. PMID:16085820

  3. 7 CFR 160.29 - Containers to remain intact.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Containers to remain intact. 160.29 Section 160.29... STANDARDS FOR NAVAL STORES Analysis, Inspection, and Grading on Request § 160.29 Containers to remain intact... the containers holding such naval stores remain intact as sampled until the analysis,...

  4. 50 CFR 622.38 - Landing fish intact.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Landing fish intact. 622.38 Section 622... § 622.38 Landing fish intact. The operator of a vessel that fishes in the EEZ is responsible for ensuring that fish on that vessel in the EEZ are maintained intact and, if taken from the EEZ,...

  5. Nitrate and the Origin of Saliva Influence Composition and Short Chain Fatty Acid Production of Oral Microcosms.

    PubMed

    Koopman, Jessica E; Buijs, Mark J; Brandt, Bernd W; Keijser, Bart J F; Crielaard, Wim; Zaura, Egija

    2016-08-01

    Nitrate is emerging as a possible health benefactor. Especially the microbial conversion of nitrate to nitrite in the oral cavity and the subsequent conversion to nitric oxide in the stomach are of interest in this regard. Yet, how nitrate influences the composition and biochemistry of the oral ecosystem is not fully understood. To investigate the effect of nitrate on oral ecology, we performed a 4-week experiment using the multiplaque artificial mouth (MAM) biofilm model. This model was inoculated with stimulated saliva of two healthy donors. Half of the microcosms (n = 4) received a constant supply of nitrate, while the other half functioned as control (n = 4). Additionally, all microcosms received a nitrate and sucrose pulse, each week, on separate days to measure nitrate reduction and acid formation. The bacterial composition of the microcosms was determined by 16S rDNA sequencing. The origin of the saliva (i.e., donor) showed to be the strongest determinant for the development of the microcosms. The supplementation of nitrate was related to a relatively high abundance of Neisseria in the microcosms of both donors, while Veillonella was highly abundant in the nitrate-supplemented microcosms of only one of the donors. The lactate concentration after sucrose addition was similarly high in all microcosms, irrespective of treatment or donor, while the concentration of butyrate was lower after nitrate addition in the nitrate-receiving microcosms. In conclusion, nitrate influences the composition and biochemistry of oral microcosms, although the result is strongly dependent on the inoculum. PMID:27155967

  6. Intact Protein Quantitation Using Pseudoisobaric Dimethyl Labeling.

    PubMed

    Fang, Houqin; Xiao, Kaijie; Li, Yunhui; Yu, Fan; Liu, Yan; Xue, Bingbing; Tian, Zhixin

    2016-07-19

    Protein structural and functional studies rely on complete qualitative and quantitative information on protein species (proteoforms); thus, it is important to quantify differentially expressed proteins at their molecular level. Here we report our development of universal pseudoisobaric dimethyl labeling (pIDL) of amino groups at both the N-terminal and lysine residues for relative quantitation of intact proteins. Initial proof-of-principle study was conducted on standard protein myoglobin and hepatocellular proteomes (HepG2 vs LO2). The amino groups from both the N-terminal and lysine were dimethylated with HXHO (X = (13)C or C) and NaBY3CN (Y = H or D). At the standard protein level, labeling efficiency, effect of product ion size, and mass resolution on quantitation accuracy were explored; and a good linear quantitation dynamic range up to 50-fold was obtained. For the hepatocellular proteome samples, 33 proteins were quantified with RSD ≤ 10% from one-dimensional reversed phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS) analysis of the 1:1 mixed samples. The method in this study can be extended to quantitation of other intact proteome systems. The universal "one-pot" dimethyl labeling of all the amino groups in a protein without the need of preblocking of those on the lysine residues is made possible by protein identification and quantitation analysis using ProteinGoggle 2.0 with customized databases of both precursor and product ions containing heavy isotopes. PMID:27359340

  7. Recollections of Parent Characteristics and Attachment Patterns for College Women of Intact vs. Non-Intact Families

    ERIC Educational Resources Information Center

    Kilmann, Peter R.; Carranza, Laura V.; Vendemia, Jennifer M. C.

    2006-01-01

    This study contrasted offsprings' attachment patterns and recollections of parent characteristics in two college samples: 147 females from intact biological parents and 157 females of parental divorce. Secure females from intact or non-intact families rated parents positively, while insecure females rated parents as absent, distant, and demanding.…

  8. Oligodeoxynucleotide Probes for Detecting Intact Cells

    NASA Technical Reports Server (NTRS)

    Rosson, Reinhardt A.; Maurina-Brunker, Julie; Langley, Kim; Pynnonen, Christine M.

    2004-01-01

    A rapid, sensitive test using chemiluminescent oligodeoxynucleotide probes has been developed for detecting, identifying, and enumerating intact cells. The test is intended especially for use in detecting and enumerating bacteria and yeasts in potable water. As in related tests that have been developed recently for similar purposes, the oligodeoxynucleotide probes used in this test are typically targeted at either singlecopy deoxyribonucleic acid (DNA) genes (such as virulence genes) or the multiple copies (10,000 to 50,000 copies per cell) of 16S ribosomal ribonucleic acids (rRNAs). Some of those tests involve radioisotope or fluorescent labeling of the probes for reporting hybridization of probes to target nucleic acids. Others of those tests involve labeling with enzymes plus the use of chemiluminescent or chromogenic substrates to report hybridization via color or the emission of light, respectively. The present test is of the last-mentioned type. The chemiluminescence in the present test can be detected easily with relatively simple instrumentation. In developing the present test, the hybridization approach was chosen because hybridization techniques are very specific. Hybridization detects stable, inheritable genetic targets within microorganisms. These targets are not dependent on products of gene expression that can vary with growth conditions or physiological states of organisms in test samples. Therefore, unique probes can be designed to detect and identify specific genera or species of bacteria or yeast (in terms of rRNA target sequences) or can be designed to detect and identify virulence genes (genomic target sequences). Because of the inherent specificity of this system, there are few problems of cross-reactivity. Hybridization tests are rapid, but hybridization tests now available commercially lack sensitivity; typically, between 10(exp 6) and 10(exp 7) cells of the target organism are needed to ensure a reliable test. Consequently, the numbers of

  9. Molecular Analysis of Microbial Community Structures in Pristine and Contaminated Aquifers: Field and Laboratory Microcosm Experiments

    PubMed Central

    Shi, Y.; Zwolinski, M. D.; Schreiber, M. E.; Bahr, J. M.; Sewell, G. W.; Hickey, W. J.

    1999-01-01

    This study used phylogenetic probes in hybridization analysis to (i) determine in situ microbial community structures in regions of a shallow sand aquifer that were oxygen depleted and fuel contaminated (FC) or aerobic and noncontaminated (NC) and (ii) examine alterations in microbial community structures resulting from exposure to toluene and/or electron acceptor supplementation (nitrate). The latter objective was addressed by using the NC and FC aquifer materials for anaerobic microcosm studies in which phylogenetic probe analysis was complemented by microbial activity assays. Domain probe analysis of the aquifer samples showed that the communities were predominantly Bacteria; Eucarya and Archaea were not detectable. At the phylum and subclass levels, the FC and NC aquifer material had similar relative abundance distributions of 43 to 65% β- and γ-Proteobacteria (B+G), 31 to 35% α-Proteobacteria (ALF), 15 to 18% sulfate-reducing bacteria, and 5 to 10% high G+C gram positive bacteria. Compared to that of the NC region, the community structure of the FC material differed mainly in an increased abundance of B+G relative to that of ALF. The microcosm communities were like those of the field samples in that they were predominantly Bacteria (83 to 101%) and lacked detectable Archaea but differed in that a small fraction (2 to 8%) of Eucarya was detected regardless of the treatment applied. The latter result was hypothesized to reflect enrichment of anaerobic protozoa. Addition of nitrate and/or toluene stimulated microbial activity in the microcosms, but only supplementation of toluene alone significantly altered community structures. For the NC material, the dominant subclass shifted from B+G to ALF, while in the FC microcosms 55 to 65% of the Bacteria community was no longer identifiable by the phylum or subclass probes used. The latter result suggested that toluene exposure fostered the proliferation of phylotype(s) that were otherwise minor constituents of the

  10. Short-term emissions of ammonia and carbon dioxide from cattle urine contaminated tropical grassland microcosm.

    PubMed

    Majumdar, Deepanjan; Patel, Manoj; Drabar, Reena; Vyas, Manish

    2006-11-01

    The study was designed to understand the emissions of ammonia (NH(3)) and carbon dioxide (CO(2)) from a single cattle urination event on a tropical grassland and underline the significance of the emissions in the context of huge animal population grazing on large pasture areas in some countries. Emissions of ammonia (NH(3)) and carbon dioxide (CO(2)) were monitored for three weeks from a tropical grassland (dominated by Cynodon dactylon Pers.) microcosm contaminated with cow and buffalo urine. The grassland microcosms were treated with urine (50 and 100 ml of each) only once and irrigated with water once every week. Ammonia was sampled by an automatic sampling system comprising of a vacuum pump, three-way stopcocks and rubber tubing and an impinger containing suitable absorbing solution (H(2)SO(4)), connected to the tubing suitably. The sampled gas, after sucked by the vacuum pump and absorbed in H(2)SO(4), was allowed to enter the closed microcosm again maintaining internal pressure of the microcosm. Carbon dioxide was sampled by absorption in an alkali (NaOH) trap inside the microcosm. Both NH(3) and CO(2) emissions were highly variable temporally and there was no continuous increasing or decreasing emission trend with time. Respectively, 45 and 46% of total NH(3)-N were emitted within first 48 h from 50 and 100 ml cow urine application while the corresponding values for buffalo urine were 34 and 32%. Total NH(3)-N emissions, integrated for sampling days (i.e. 1, 2, 3, 4, 6, 15, 18 and 21st) were 11 and 6% in cow and 8 and 5% in buffalo urine, of the total-N added through 50 and 100 ml urine samples. Carbon dioxide emissions were standardized at 25 degrees C by using a suitable formula which were lower than actual emissions at actual soil temperature (> 25 degrees C). Carbon dioxide emission rates were classified on the basis of soil repiratory classification and classes ranged from moderately low soil activity up to unusually high soil activity, the latter

  11. Protein methylation reactions in intact pea chloroplasts

    SciTech Connect

    Niemi, K.J. )

    1989-04-01

    Post-translational protein methylation was investigated in Pisum sativum chloroplasts. Intact pea chloroplasts were incubated with ({sup 3}H-methyl)-S-adenosylmethionine under various conditions. The chloroplasts were then separated into stromal and thylakoid fractions and analyzed for radioactivity transferred to protein. Light enhanced the magnitude of labeling in both fractions. One thylakoid polypeptide with an apparent molecular mass of 43 kDa was labeled only in the light. Several other thylakoid and stromal proteins were labeled in both light and dark-labeling conditions. Both base-labile methylation, carboxy-methylesters and base-stable groups, N-methylations were found. Further characterization of the methyl-transfer reactions will be presented.

  12. Drilling to gabbro in intact ocean crust.

    PubMed

    Wilson, Douglas S; Teagle, Damon A H; Alt, Jeffrey C; Banerjee, Neil R; Umino, Susumu; Miyashita, Sumio; Acton, Gary D; Anma, Ryo; Barr, Samantha R; Belghoul, Akram; Carlut, Julie; Christie, David M; Coggon, Rosalind M; Cooper, Kari M; Cordier, Carole; Crispini, Laura; Durand, Sedelia Rodriguez; Einaudi, Florence; Galli, Laura; Gao, Yongjun; Geldmacher, Jörg; Gilbert, Lisa A; Hayman, Nicholas W; Herrero-Bervera, Emilio; Hirano, Nobuo; Holter, Sara; Ingle, Stephanie; Jiang, Shijun; Kalberkamp, Ulrich; Kerneklian, Marcie; Koepke, Jürgen; Laverne, Christine; Vasquez, Haroldo L Lledo; Maclennan, John; Morgan, Sally; Neo, Natsuki; Nichols, Holly J; Park, Sung-Hyun; Reichow, Marc K; Sakuyama, Tetsuya; Sano, Takashi; Sandwell, Rachel; Scheibner, Birgit; Smith-Duque, Chris E; Swift, Stephen A; Tartarotti, Paola; Tikku, Anahita A; Tominaga, Masako; Veloso, Eugenio A; Yamasaki, Toru; Yamazaki, Shusaku; Ziegler, Christa

    2006-05-19

    Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but it has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismic layer 2, 1157 meters into crust formed at a superfast spreading rate. The gabbros are the crystallized melt lenses that formed beneath a mid-ocean ridge. The depth at which gabbro was reached confirms predictions extrapolated from seismic experiments at modern mid-ocean ridges: Melt lenses occur at shallower depths at faster spreading rates. The gabbros intrude metamorphosed sheeted dikes and have compositions similar to the overlying lavas, precluding formation of the cumulate lower oceanic crust from melt lenses so far penetrated by Hole 1256D. PMID:16627698

  13. Mass Spectrometry of Intact Membrane Protein Complexes

    PubMed Central

    Laganowsky, Arthur; Reading, Eamonn; Hopper, Jonathan T.S.; Robinson, Carol V.

    2014-01-01

    Mass spectrometry of intact soluble protein complexes has emerged as a powerful technique to study the stoichiometry, structure-function and dynamics of protein assemblies. Recent developments have extended this technique to the study of membrane protein complexes where it has already revealed subunit stoichiometries and specific phospholipid interactions. Here, we describe a protocol for mass spectrometry of membrane protein complexes. The protocol begins with preparation of the membrane protein complex enabling not only the direct assessment of stoichiometry, delipidation, and quality of the target complex, but also evaluation of the purification strategy. A detailed list of compatible non-ionic detergents is included, along with a protocol for screening detergents to find an optimal one for mass spectrometry, biochemical and structural studies. This protocol also covers the preparation of lipids for protein-lipid binding studies and includes detailed settings for a Q-ToF mass spectrometer after introduction of complexes from gold-coated nanoflow capillaries. PMID:23471109

  14. A simple, inexpensive, and field-relevant microcosm tidal simulator for use in marsh macrophyte studies1

    PubMed Central

    MacTavish, Rachel M.; Cohen, Risa A.

    2014-01-01

    • Premise of the study: A microcosm unit with tidal simulation was developed to address the challenge of maintaining ecologically relevant tidal regimes while performing controlled greenhouse experiments on smooth cordgrass, Spartina alterniflora. • Methods and Results: We designed a simple, inexpensive, easily replicated microcosm unit with tidal simulation and tested whether S. alterniflora growth in microcosms with tidal simulation was similar to that of tidally influenced plants in the field on Sapelo Island, Georgia. After three months of exposure to either natural or simulated tidal treatment, plants in microcosms receiving tidal simulation had similar stem density, height, and above- and belowground biomass to plants in field plots. • Conclusions: The tidal simulator developed may provide an inexpensive, effective method for conducting studies on S. alterniflora and other tidally influenced plants in controlled settings to be used not only to complement field studies, but also in locations without coastal access. PMID:25383265

  15. Mineralogical, chemical, organic and microbial properties of subsurface soil cores from Mars Desert Research Station (Utah, USA): Phyllosilicate and sulfate analogues to Mars mission landing sites

    NASA Astrophysics Data System (ADS)

    Stoker, Carol R.; Clarke, Jonathan; Direito, Susana O. L.; Blake, David; Martin, Kevin R.; Zavaleta, Jhony; Foing, Bernard

    2011-07-01

    We collected and analysed soil cores from four geologic units surrounding Mars Desert Research Station (MDRS) Utah, USA, including Mancos Shale, Dakota Sandstone, Morrison formation (Brushy Basin member) and Summerville formation. The area is an important geochemical and morphological analogue to terrains on Mars. Soils were analysed for mineralogy by a Terra X-ray diffractometer (XRD), a field version of the CheMin instrument on the Mars Science Laboratory (MSL) mission (2012 landing). Soluble ion chemistry, total organic content and identity and distribution of microbial populations were also determined. The Terra data reveal that Mancos and Morrison soils are rich in phyllosilicates similar to those observed on Mars from orbital measurements (montmorillonite, nontronite and illite). Evaporite minerals observed include gypsum, thenardite, polyhalite and calcite. Soil chemical analysis shows sulfate the dominant anion in all soils and SO4>>CO3, as on Mars. The cation pattern Na>Ca>Mg is seen in all soils except for the Summerville where Ca>Na. In all soils, SO4 correlates with Na, suggesting sodium sulfates are the dominant phase. Oxidizable organics are low in all soils and range from a high of 0.7% in the Mancos samples to undetectable at a detection limit of 0.1% in the Morrison soils. Minerals rich in chromium and vanadium were identified in Morrison soils that result from diagenetic replacement of organic compounds. Depositional environment, geologic history and mineralogy all affect the ability to preserve and detect organic compounds. Subsurface biosphere populations were revealed to contain organisms from all three domains (Archaea, Bacteria and Eukarya) with cell density between 3.0×106 and 1.8×107 cells ml-1 at the deepest depth. These measurements are analogous to data that could be obtained on future robotic or human Mars missions and results are relevant to the MSL mission that will investigate phyllosilicates on Mars.

  16. Survival study of enterotoxigenic Escherichia colistrain in seawater and wastewater microcosms.

    PubMed

    Boukef Ben Omrane, I; El Bour, M; Mejri, S; Mraouna, R; Got, P; Troussellier, M; Boudabous, A

    2011-01-01

    In order to survey osmotic and oligotrophic stress consequence on pathogenic enterobacteria discharged in marine areas, we examined enterotoxigenic Escherichia coli (ETEC) and a reference (Ecoli O126:B16) strains during their survival (47 days) in wastewater microcosms, submerged in natural seawater and maintained in laboratory conditions. The results revealed that the survival time for the two strains was prolonged when bacterial cells were previously incubated in wastewater, with less cellular membrane damage. In addition, the wild clinical E. coli strain showed a better survival capacity than the reference E. coli strain one. For both, we noted some modifications in biochemical profiles relatively to the initial state, notably when they were previously incubated in wastewater microcosm. PMID:23461140

  17. Comparing the impacts of sediment-bound bifenthrin on aquatic macroinvertebrates in laboratory bioassays and field microcosms.

    PubMed

    Boyle, Rhianna L; Hoak, Molly N; Pettigrove, Vincent J; Hoffmann, Ary A; Long, Sara M

    2016-11-01

    We conducted two laboratory bioassays and two field microcosm exposures with bifenthrin (a synthetic pyrethroid) in order to evaluate the capacity of single-species laboratory bioassays to predict lethal and sublethal impacts on aquatic invertebrates in microcosms. For the laboratory species, Chironomus tepperi, larval survival was reduced by 24% at 53.66µg/g OC, while adult emergence was reduced at concentrations of 33.33µg/g OC and higher, with a 61% decrease at 77.78µg/g OC and no emergence at 126.67µg/g OC. The abundance of several other microcosm taxa was reduced in the microcosms at a similar concentration range (33.33µg/g OC and above), however there was no impact on the abundance of the congeneric species, Chironomus oppositus. The differences in impacts between test systems were potentially due to both differing species sensitivity and the interaction of ambient temperature with bifenthrin toxicity. Bifenthrin also was associated with early emergence of Chironomus sp. in both test systems, at concentrations of 10µg/g OC and higher (laboratory) and 43.90µg/g OC (microcosm), and with a significant decrease in the proportion of C. oppositus males in a microcosm. These findings indicate that while laboratory bioassays accurately predict many impacts in the field, there are some limitations to the predictive capacity of these tests. PMID:27544659

  18. Microcosm studies of microbial degradation in a coal tar distillate plume

    NASA Astrophysics Data System (ADS)

    Harrison, I.; Williams, G. M.; Higgo, J. J. W.; Leader, R. U.; Kim, A. W.; Noy, D. J.

    2001-12-01

    Investigation of a groundwater plume containing up to 24 g l -1 phenolic compounds suggested that over a period of nearly 50 years, little degradation had occurred despite the presence of a microbial community and electron acceptors within the core of the plume. In order to study the effect of contaminant concentration on degradation behaviour, laboratory microcosm experiments were performed under aerobic and anaerobic conditions at four different concentrations obtained by diluting contaminated with uncontaminated groundwater. The microcosms contained groundwater with total phenols at ca. 200, 250, 660 and 5000 mg l -1, and aquifer sediment that had been acclimatised within the plume for several months. The microcosms were operated for a period of 390-400 days along with sterile controls to ascertain whether degradation was microbially mediated or abiotic. Under aerobic conditions, degradation only occurred at concentrations up to 660 mg l -1 total phenols. At phenol concentrations below 250 mg l -1, a benzoquinone intermediate, thought to originate from the degradation of 2,5-dimethylphenol, was isolated and identified. This suggested an unusual degradative pathway for this compound; its aerobic degradation more commonly proceeding via catecholic intermediates. Under anaerobic conditions, degradation only occurred in the most dilute microcosm (total phenols 195 mg l -1) with a loss of p-cresol accompanied by a nonstoichiometric decrease in nitrate and sulphate. By inference, iron(III) from the sediment may also have been used as a terminal electron acceptor, in which case the amount of biologically available iron released was calculated as 1.07 mg Fe(III)/g of sediment. The study shows that natural attenuation is likely to be stimulated by dilution of the plume.

  19. Direct Link between Toluene Degradation in Contaminated-Site Microcosms and a Polaromonas Strain ▿

    PubMed Central

    Sun, Weimin; Xie, Shuguang; Luo, Chunling; Cupples, Alison M.

    2010-01-01

    Stable isotope probing (SIP) was used to identify the aerobic toluene-degrading microorganism in soil microcosms. Several approaches (terminal restriction fragment length polymorphism, 16S rRNA gene sequencing, and quantitative PCR) provided evidence that the microorganism responsible was a member of the genus Polaromonas and could grow on toluene. This microorganism also transformed benzene, but not m-xylene or cis-dichloroethene. PMID:20008173

  20. Survival and impact of genetically engineered Pseudomonas putida harboring mercury resistance gene in aquatic microcosms.

    PubMed

    Iwasaki, K; Uchiyama, H; Yagi, O

    1993-08-01

    The survival of wild-type and genetically engineered Pseudomonas putida PpY101 that contained a recombinant plasmid pSR134 conferring mercury resistance were monitored in aquatic microcosms. We used lake, river, and spring water samples. The density of genetically engineered and wild-type P. putida decreased rapidly within 5 days (population change rate k -0.87 approximately -1.00 day-1), then moderately after 5 to 28 days (-0.10 approximately -0.14 day-1). The population change rates of genetically engineered and wild-type P. putida were not significantly different. We studied the important factors affecting the survival of genetically engineered and wild-type P. putida introduced in aquatic microcosms. Visible light exerted an adverse effect on the survival of the two strains. The densities of genetically engineered and wild-type P. putida were almost constant until 7 days after inoculation in natural water filtered with a 0.45-micron membrane filter, or treated with cycloheximide to inhibit the growth of protozoa. These results suggested that protozoan predation was one of the most important factors for the survival of two strains. We examined the impact of the addition of genetically engineered and wild-type P. putida on indigenous bacteria and protozoa. Inoculation of genetically engineered or wild-type P. putida had no apparent effect on the density of indigenous bacteria. The density of protozoa increased in microcosms inoculated with genetically engineered or wild-type P. putida at 3 days after inoculation, but after 5 to 21 days, the density of protozoa decreased to the same level as the control microcosms. PMID:7764012

  1. Selective Enrichment Yields Robust Ethene-Producing Dechlorinating Cultures from Microcosms Stalled at cis-Dichloroethene

    PubMed Central

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

    2014-01-01

    Dehalococcoides mccartyi strains are of particular importance for bioremediation due to their unique capability of transforming perchloroethene (PCE) and trichloroethene (TCE) to non-toxic ethene, through the intermediates cis-dichloroethene (cis-DCE) and vinyl chloride (VC). Despite the widespread environmental distribution of Dehalococcoides, biostimulation sometimes fails to promote dechlorination beyond cis-DCE. In our study, microcosms established with garden soil and mangrove sediment also stalled at cis-DCE, albeit Dehalococcoides mccartyi containing the reductive dehalogenase genes tceA, vcrA and bvcA were detected in the soil/sediment inocula. Reductive dechlorination was not promoted beyond cis-DCE, even after multiple biostimulation events with fermentable substrates and a lengthy incubation. However, transfers from microcosms stalled at cis-DCE yielded dechlorination to ethene with subsequent enrichment cultures containing up to 109 Dehalococcoides mccartyi cells mL−1. Proteobacterial classes which dominated the soil/sediment communities became undetectable in the enrichments, and methanogenic activity drastically decreased after the transfers. We hypothesized that biostimulation of Dehalococcoides in the cis-DCE-stalled microcosms was impeded by other microbes present at higher abundances than Dehalococcoides and utilizing terminal electron acceptors from the soil/sediment, hence, outcompeting Dehalococcoides for H2. In support of this hypothesis, we show that garden soil and mangrove sediment microcosms bioaugmented with their respective cultures containing Dehalococcoides in high abundance were able to compete for H2 for reductive dechlorination from one biostimulation event and produced ethene with no obvious stall. Overall, our results provide an alternate explanation to consolidate conflicting observations on the ubiquity of Dehalococcoides mccartyi and occasional stalling of dechlorination at cis-DCE; thus, bringing a new perspective to better

  2. Impact of imidacloprid on life-cycle development of Coccinella septempunctata in laboratory microcosms.

    PubMed

    Yu, Caihong; Lin, Ronghua; Fu, Maoran; Zhou, Yanming; Zong, Fulin; Jiang, Hui; Lv, Ning; Piao, Xiuying; Zhang, Jia; Liu, Yongquan; Brock, Theo C M

    2014-12-01

    Long-term effects of a single application of imidacloprid on ladybird beetle, Coccinella septempunctata L., were studied in indoor laboratory microcosms, starting with the 2nd instar larvae of C. septempunctata but covering the full life cycle. The microcosms comprised enclosures containing a pot with soil planted with broad bean plants and black bean aphid, Aphis craccivora Koch, as food. Exposure doses (0.85-13.66g a.i. ha(-1)) in the long-term microcosm experiment were based on a preliminary short-term (72h) toxicity test with 2nd instar larvae. The measurement endpoints used to calculate NOERs (No Observed Effect application Rates) included development time, hatching, pupation, adult emergence, survival and number of eggs produced. Furthermore, for these endpoints ER50 (application rate causing 50 percent effect) and LR50 (application rate causing 50 percent mortality) values were calculated when possible. The single imidacloprid application affected survival (lowest LR50 4.07g a.i. ha(-1); NOER 3.42g a.i. ha(-1)), egg production (ER50 26.63g a.i. ha(-1)) and egg hatching (NOER 6.83g a.i. ha(-1)). Statistically significant treatment-related effects on the whole development duration, pupation and adult emergence could not be demonstrated (NOER≥13.66g a.i. ha(-1)). The lowest L(E)R50 values and NOERs derived from the laboratory microcosm test with C. septempunctata are lower than the reported field application rates of imidacloprid (15-60g a.i. ha(-1)) in cotton cultivation in China, suggesting potential risks to beneficial arthropods. PMID:25240465

  3. Mercury Distribution, Methylation and Volatilization in Microcosms with and without the Sea Anemone Bunodosoma caissarum

    NASA Astrophysics Data System (ADS)

    Ansari, N. R.; Correia, R. R. S.; Fernandez, M. A. S.; Cordeiro, R. C.; Guimarães, J. R. D.

    2014-12-01

    Mercury (Hg) can be a dangerous contaminant and has a complex biogeochemical cycling in aquatic environments. The sea anemone Bunodosoma caissarum is an endemic species in Brazil capable of bioaccumulating Hg from the ambient seawater. The radiotracer 203Hg was used in order to investigate mechanisms of Hg uptake and depuration of B. caissarum and the distribution of Hg in laboratory model systems, with and without B. caissarum. A single initial spike of 203Hg was added to each microcosm. Microcosms had continuous air renovation and trapping of Hg volatile forms. Total Hg in different compartments was measured by gamma spectrometry. In the uptake experiment 203Hg activity was determined periodically in seawater and specimens for 6 days. At the end, specimens had an average bioconcentration factor of 70. After the uptake experiment, methylmercury (MeHg) in seawater was extracted and measured by liquid scintillation. In microcosms with and without B. caissarum, respectively 0.05% and 0.32% of the initial spike was found as MeHg. Hg was probably less available for methylation in the first because of bioaccumulation and higher concentrations of suspended particulate matter that could form complexes with Hg. After that, specimens were transferred to unspiked microcosms. After a 48 day depuration specimens still retained 35 - 70% of the previously bioaccumulated Hg and 0.2 - 2.4% of the total Hg was MeHg. The presence of B. caissarum resulted in an unexpected higher volatilization of Hg (58%) compared to controls (17%). This increased volatilization is possibly a result of Hg2+ reduction mediated by microorganisms associated with its tissues and mucus secretions and/or an unknown defense mechanism of this species.

  4. Polychlorinated biphenyl (PCB) anaerobic degradation in marine sediments: microcosm study and role of autochthonous microbial communities.

    PubMed

    Matturro, Bruna; Ubaldi, Carla; Grenni, Paola; Caracciolo, Anna Barra; Rossetti, Simona

    2016-07-01

    Polychlorobiphenyl (PCB) biodegradation was followed for 1 year in microcosms containing marine sediments collected from Mar Piccolo (Taranto, Italy) chronically contaminated by this class of hazardous compounds. The microcosms were performed under strictly anaerobic conditions with or without the addition of Dehalococcoides mccartyi, the main microorganism known to degrade PCBs through the anaerobic reductive dechlorination process. Thirty PCB congeners were monitored during the experiments revealing that the biodegradation occurred in all microcosms with a decrease in hepta-, hexa-, and penta-chlorobiphenyls (CBs) and a parallel increase in low chlorinated PCBs (tri-CBs and tetra-CBs). The concentrations of the most representative congeners detected in the original sediment, such as 245-245-CB and 2345-245-CB, and of the mixture 2356-34-CB+234-245-CB, decreased by 32.5, 23.8, and 46.7 %, respectively, after only 70 days of anaerobic incubation without any bioaugmentation treatment. Additionally, the structure and population dynamics of the microbial key players involved in the biodegradative process and of the entire mixed microbial community were accurately defined by Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) in both the original sediment and during the operation of the microcosm. The reductive dehalogenase genes of D. mccartyi, specifically involved in PCB dechlorination, were also quantified using real-time PCR (qPCR). Our results demonstrated that the autochthonous microbial community living in the marine sediment, including D. mccartyi (6.32E+06 16S rRNA gene copy numbers g(-1) sediment), was able to efficiently sustain the biodegradation of PCBs when controlled anaerobic conditions were imposed. PMID:26162439

  5. Modelling algae-duckweed interaction under chemical pressure within a laboratory microcosm.

    PubMed

    Lamonica, Dominique; Clément, Bernard; Charles, Sandrine; Lopes, Christelle

    2016-06-01

    Contaminant effects on species are generally assessed with single-species bioassays. As a consequence, interactions between species that occur in ecosystems are not taken into account. To investigate the effects of contaminants on interacting species dynamics, our study describes the functioning of a 2-L laboratory microcosm with two species, the duckweed Lemna minor and the microalgae Pseudokirchneriella subcapitata, exposed to cadmium contamination. We modelled the dynamics of both species and their interactions using a mechanistic model based on coupled ordinary differential equations. The main processes occurring in this two-species microcosm were thus formalised, including growth and settling of algae, growth of duckweeds, interspecific competition between the two species and cadmium effects. We estimated model parameters by Bayesian inference, using simultaneously all the data issued from multiple laboratory experiments specifically conducted for this study. Cadmium concentrations ranged between 0 and 50 μg·L(-1). For all parameters of our model, we obtained biologically realistic values and reasonable uncertainties. Only duckweed dynamics was affected by interspecific competition, while algal dynamics was not impaired. Growth rate of both species decreased with cadmium concentration, as well as competition intensity showing that the interspecific competition pressure on duckweed decreased with cadmium concentration. This innovative combination of mechanistic modelling and model-guided experiments was successful to understand the algae-duckweed microcosm functioning without and with contaminant. This approach appears promising to include interactions between species when studying contaminant effects on ecosystem functioning. PMID:26922150

  6. Magnetotactic bacteria in microcosms originating from the French Mediterranean Coast subjected to oil industry activities.

    PubMed

    Postec, Anne; Tapia, Nicolas; Bernadac, Alain; Joseph, Manon; Davidson, Sylvain; Wu, Long-Fei; Ollivier, Bernard; Pradel, Nathalie

    2012-01-01

    Magnetotactic bacteria (MTB) mineralize nanosized magnetite or greigite crystals within cells and thus play an important role in the biogeochemical process. Despite decades of research, knowledge of MTB distribution and ecology, notably in areas subjected to oil industry activities, is still limited. In the present study, we investigated the presence of MTB in the Gulf of Fos, French Mediterranean coast, which is subjected to intensive oil industry activities. Microcosms containing sediments/water (1:2, v/v) from several sampling sites were monitored over several weeks. The presence of MTB was revealed in five of eight sites. Diverse and numerous MTB were revealed particularly from one site (named CAR), whilst temporal variations of a homogenous magnetotactic cocci population was shown within the LAV site microcosm over a 4-month period. Phylogenetic analysis revealed that they belonged to Alphaproteobacteria, and a novel genus from the LAV site was evidenced. Among the physicochemical parameters measured, a correlation was shown between the variation of MTB abundance in microcosms and the redox state of sulphur compounds. PMID:21766218

  7. Aerobic Vinyl Chloride Metabolism in Groundwater Microcosms by Methanotrophic and Etheneotrophic Bacteria.

    PubMed

    Findlay, Margaret; Smoler, Donna F; Fogel, Samuel; Mattes, Timothy E

    2016-04-01

    Vinyl chloride (VC) is a carcinogen generated in groundwater by reductive dechlorination of chloroethenes. Under aerobic conditions, etheneotrophs oxidize ethene and VC, while VC-assimilators can use VC as their sole source of carbon and energy. Methanotrophs utilize only methane but can oxidize ethene to epoxyethane and VC to chlorooxirane. Microcosms were constructed with groundwater from the Carver site in MA containing these three native microbial types. Methane, ethene, and VC were added to the microcosms singly or as mixtures. In the absence of VC, ethene degraded faster when methane was also present. We hypothesized that methanotroph oxidation of ethene to epoxyethane competed with their use of methane, and that epoxyethane stimulated the activity of starved etheneotrophs by inducing the enzyme alkene monooxygenase. We then developed separate enrichment cultures of Carver methanotrophs and etheneotrophs, and demonstrated that Carver methanotrophs can oxidize ethene to epoxyethane, and that starved Carver etheneotrophs exhibit significantly reduced lag time for ethene utilization when epoxyethane is added. In our groundwater microcosm tests, when all three substrates were present, the rate of VC removal was faster than with either methane or ethene alone, consistent with the idea that methanotrophs stimulate etheneotroph destruction of VC. PMID:26918370

  8. Glyceria maxima as new test species for the EU risk assessment for herbicides: a microcosm study.

    PubMed

    Mohr, S; Schott, J; Hoenemann, L; Feibicke, M

    2015-03-01

    In its recent guidance document on tiered risk assessment for plant protection products for aquatic organisms, the European Food Safety Authority (EFSA) proposed to use Glyceria maxima as monocotyledonous grass species for the testing of special herbicide groups. However, published toxicity data for this species is very limited and there is no test guideline for Glyceria sp. For this reason a microcosm study was conducted in order to gain experience on the degree of sensitivity of G. maxima to the herbicidal substances clodinafop-propargyl (grass herbicide) and fluroxypyr (auxin) in comparison to the already established test organism water milfoil Myriophyllum spicatum and the duckweed species Landoltia punctata. Five concentrations without replicates were tested for each test substance using 10 microcosms and three microcosms served as controls. The experiment was run for 8 weeks. Morphological endpoints were used to determine growth and EC50 values. The results show that M. spicatum was most sensitive to fluroxypyr (37 days EC50 for roots: 62 µg/L) and G. maxima most sensitive to clodinafop-propargyl (22 days EC50 for total shoot length: 48 µg/L) whereas the duckweed species was considerable less sensitive. Hence, G. maxima turns out to be a good candidate for testing grass specific herbicides, supporting its inclusion as an additional macrophyte test for the risk assessment of herbicides as proposed by the EFSA. PMID:25380672

  9. Microbial abundance and community in subsurface flow constructed wetland microcosms: role of plant presence.

    PubMed

    Wang, Qian; Xie, Huijun; Ngo, Huu Hao; Guo, Wenshan; Zhang, Jian; Liu, Cui; Liang, Shuang; Hu, Zhen; Yang, Zhongchen; Zhao, Congcong

    2016-03-01

    In this research, the role of plants in improving microorganism growth conditions in subsurface flow constructed wetland (CW) microcosms was determined. In particular, microbial abundance and community were investigated during summer and winter in Phragmites australis-planted CW microcosms (PA) and unplanted CW microcosms (control, CT). Results revealed that the removal efficiencies of pollutants and microbial community structure varied in winter with variable microbial abundance. During summer, PA comprised more dominant phyla (e.g., Proteobacteria, Actinobacteria, and Bacteroidetes), whereas CT contained more Cyanobacteria and photosynthetic bacteria. During winter, the abundance of Proteobacteria was >40 % in PA but dramatically decreased in CT. Moreover, Cyanobacteria and photosynthetic bacterial dominance in CT decreased. In both seasons, bacteria were more abundant in root surfaces than in sand. Plant presence positively affected microbial abundance and community. The potential removal ability of CT, in which Cyanobacteria and photosynthetic bacteria were abundant during summer, was more significantly affected by temperature reduction than that of PA with plant presence. PMID:25772872

  10. Mercury distribution, methylation and volatilization in microcosms with and without the sea anemone Bunodosoma caissarum.

    PubMed

    Rizzini Ansari, Nafisa; Correia, Raquel Rose Silva; Fernandez, Marcos Antônio; Cordeiro, Renato Campello; Guimarães, Jean Remy Davée

    2015-03-15

    Mercury (Hg) has a complex biogeochemical cycle in aquatic environments. Its most toxic form, methylmercury (MeHg), is produced by microorganisms. This study investigated how the sea anemone Bunodosoma caissarum affects Hg distribution, methylation and volatilization in laboratory model systems. (203)Hg was added to microcosms and its distribution in seawater, specimens and air was periodically measured by gamma spectrometry. MeHg was measured by liquid scintillation. After the uptake period, specimens had a bioconcentration factor of 70 and in microcosms with and without B. caissarum, respectively 0.05% and 0.32% of the initial spike was found as MeHg. After depuration, MeHg in specimens ranged from 0.2% to 2.4% of total Hg. Microcosms with B. caissarum had higher Hg volatilization (58%) than controls (17%), possibly due to Hg(2+) reduction mediated by microorganisms associated with its tissues and mucus secretions. Marine organisms and their associated microbiota may play a role in Hg and MeHg cycling. PMID:25599628

  11. Emissions of NO and N2O in wetland microcosms for swine wastewater treatment.

    PubMed

    Zhang, Shunan; Liu, Feng; Xiao, Runlin; Li, Yong; Zhou, Juan; Wu, Jinshui

    2015-12-01

    Nitric oxide (NO) and nitrous oxide (N2O) emitted from wetland systems contribute an important proportion to the global warming effect. In this study, four wetland microcosms vegetated with Myriophyllum elatinoides (WM), Alternanthera philoxeroides (WA), Eichhornia crassipes (WE), or without vegetation (NW) were compared to investigate the emissions of NO and N2O during nitrogen (N) removal process when treating swine wastewater. After 30-day incubation, TN removal rates of 96.4, 74.2, 97.2, and 47.3 % were observed for the WM, WA, WE, and NW microcosms, respectively. Yet, no significant difference was observed in WM and WE (p > 0.05). The average NO and N2O emissions in WE was significantly higher than those in WM, WA, and NW (p < 0.05). In addition, the emission of N2O in WE accounted for 2.10 % of initial TN load and 2.17 % of the total amount of TN removal, compared with less than 1 % in the other microcosms. These findings indicate that wetland vegetated with M. elatinoides may be an optimal system for swine wastewater treatment, based on its higher removal of N and lower emissions of NO and N2O. PMID:26289333

  12. Enhanced and Stabilized Arsenic Retention in Microcosms through the Microbial Oxidation of Ferrous Iron by Nitrate

    PubMed Central

    SUN, JING; CHILLRUD, STEVEN N.; MAILLOUX, BRIAN J.; STUTE, MARTIN; SINGH, RAJESH; DONG, HAILIANG; LEPRE, CHRISTOPHER J.; BOSTICK, BENJAMIN C.

    2016-01-01

    Magnetite strongly retains As, and is relatively stable under Fe(III)-reducing conditions common in aquifers that release As. Here, laboratory microcosm experiments were conducted to investigate a potential As remediation method involving magnetite formation, using groundwater and sediments from the Vineland Superfund site. The microcosms were amended with various combinations of nitrate, Fe(II)(aq)(as ferrous sulfate) and lactate, and were incubated for more than 5 weeks. In the microcosms enriched with 10 mM nitrate and 5 mM Fe(II)(aq), black magnetic particles were produced, and As removal from solution was observed even under sustained Fe(III) reduction stimulated by the addition of 10 mM lactate. The enhanced As retention was mainly attributed to co-precipitation within magnetite and adsorption on a mixture of magnetite and ferrihydrite. Sequential chemical extraction, X-ray absorption spectroscopy and magnetic susceptibility measurements showed that these minerals formed at pH 6 – 7 following nitrate-Fe(II) addition, and As-bearing magnetite was stable under reducing conditions. Scanning electron microscopy and X-ray diffraction indicated that nano-particulate magnetite was produced as coatings on fine sediments, and no aging effect was detected on morphology over the course of incubation. These results suggest that a magnetite based strategy may be a long-term remedial option for As-contaminated aquifers. PMID:26454120

  13. Identification of active oxalotrophic bacteria by Bromodeoxyuridine DNA labeling in a microcosm soil experiments.

    PubMed

    Bravo, Daniel; Martin, Gaëtan; David, Maude M; Cailleau, Guillaume; Verrecchia, Eric; Junier, Pilar

    2013-11-01

    The oxalate-carbonate pathway (OCP) leads to a potential carbon sink in terrestrial environments. This process is linked to the activity of oxalotrophic bacteria. Although isolation and molecular characterizations are used to study oxalotrophic bacteria, these approaches do not give information on the active oxalotrophs present in soil undergoing the OCP. The aim of this study was to assess the diversity of active oxalotrophic bacteria in soil microcosms using the Bromodeoxyuridine (BrdU) DNA labeling technique. Soil was collected near an oxalogenic tree (Milicia excelsa). Different concentrations of calcium oxalate (0.5%, 1%, and 4% w/w) were added to the soil microcosms and compared with an untreated control. After 12 days of incubation, a maximal pH of 7.7 was measured for microcosms with oxalate (initial pH 6.4). At this time point, a DGGE profile of the frc gene was performed from BrdU-labeled soil DNA and unlabeled soil DNA. Actinobacteria (Streptomyces- and Kribbella-like sequences), Gammaproteobacteria and Betaproteobacteria were found as the main active oxalotrophic bacterial groups. This study highlights the relevance of Actinobacteria as members of the active bacterial community and the identification of novel uncultured oxalotrophic groups (i.e. Kribbella) active in soils. PMID:24033776

  14. Microcosm for assessing survival of genetically engineered microorganisms in aquatic environments.

    PubMed Central

    Awong, J; Bitton, G; Chaudhry, G R

    1990-01-01

    Laboratory-contained microcosms are important for studying the fate and survival of genetically engineered microorganisms. In this study, we describe a simple aquatic microcosm that utilizes survival chambers in a flowthrough or static renewal system. The model was used to study the survival of genetically engineered and wild-type strains of Escherichia coli and Pseudomonas putida in the lake water environment. Temperature-dependent studies indicated that the genetically engineered microorganisms survived better or at least as well as their wild-type counterparts at 15, 25, and 30 degrees C. The genetic determinants of the genetically engineered microorganisms also remained fairly stable within the host cell under the tested conditions. In the presence of organisms indigenous to lake water, E. coli was eliminated after 20 days, whereas P. putida showed an initial decline but was able to stabilize its population after 5 days. A herbicide, Hydrothol-191, caused a significant decline in numbers of P. putida, but no significant difference was observed between the genetically engineered microorganisms and the wild-type strain. The microcosm described is simple, can be easily adapted to study a variety of environmental variables, and has the advantage that the organisms tested are constantly exposed to test waters that are continuously renewed. PMID:2187407

  15. Enhanced and stabilized arsenic retention in microcosms through the microbial oxidation of ferrous iron by nitrate.

    PubMed

    Sun, Jing; Chillrud, Steven N; Mailloux, Brian J; Stute, Martin; Singh, Rajesh; Dong, Hailiang; Lepre, Christopher J; Bostick, Benjamin C

    2016-02-01

    Magnetite strongly retains As, and is relatively stable under Fe(III)-reducing conditions common in aquifers that release As. Here, laboratory microcosm experiments were conducted to investigate a potential As remediation method involving magnetite formation, using groundwater and sediments from the Vineland Superfund site. The microcosms were amended with various combinations of nitrate, Fe(II) (aq) (as ferrous sulfate) and lactate, and were incubated for more than 5 weeks. In the microcosms enriched with 10 mM nitrate and 5 mM Fe(II) (aq), black magnetic particles were produced, and As removal from solution was observed even under sustained Fe(III) reduction stimulated by the addition of 10 mM lactate. The enhanced As retention was mainly attributed to co-precipitation within magnetite and adsorption on a mixture of magnetite and ferrihydrite. Sequential chemical extraction, X-ray absorption spectroscopy and magnetic susceptibility measurements showed that these minerals formed at pH 6-7 following nitrate-Fe(II) addition, and As-bearing magnetite was stable under reducing conditions. Scanning electron microscopy and X-ray diffraction indicated that nano-particulate magnetite was produced as coatings on fine sediments, and no aging effect was detected on morphology over the course of incubation. These results suggest that a magnetite based strategy may be a long-term remedial option for As-contaminated aquifers. PMID:26454120

  16. Microbial Characterization of Biofilms in Domestic Drains and the Establishment of Stable Biofilm Microcosms

    PubMed Central

    McBain, Andrew J.; Bartolo, Robert G.; Catrenich, Carl E.; Charbonneau, Duane; Ledder, Ruth G.; Rickard, Alexander H.; Symmons, Sharon A.; Gilbert, Peter

    2003-01-01

    We have used heterotrophic plate counts, together with live-dead direct staining and denaturing gradient gel electrophoresis (DGGE), to characterize the eubacterial communities that had formed as biofilms within domestic sink drain outlets. Laboratory microcosms of these environments were established using excised biofilms from two separate drain biofilm samples to inoculate constant-depth film fermentors (CDFFs). Drain biofilms harbored 9.8 to 11.3 log10 cells of viable enteric species and pseudomonads/g, while CDFF-grown biofilms harbored 10.6 to 11.4 log10 cells/g. Since live-dead direct staining revealed various efficiencies of recovery by culture, samples were analyzed by DGGE, utilizing primers specific for the V2-V3 region of eubacterial 16S rDNA. These analyses showed that the major PCR amplicons from in situ material were represented in the microcosms and maintained there over extended periods. Sequencing of amplicons resolved by DGGE revealed that the biofilms were dominated by a small number of genera, which were also isolated by culture. One drain sample harbored the protozoan Colpoda maupasi, together with rhabtidid nematodes and bdelloid rotifers. The microcosm enables the maintenance of stable drain-type bacterial communities and represents a useful tool for the modeling of this ecosystem. PMID:12513993

  17. Microcosm enrichment of biphenyl-degrading microbial communities from soils and sediments

    SciTech Connect

    Wagner-Doebler, I.; Bennasar, A.; Stroempl, C.; Bruemmer, I.; Eichner, C.; Grammel, I.; Moore, E.R.B.; Vancanneyt, M.

    1998-08-01

    A microcosm enrichment approach was employed to isolate bacteria which are representative of long-term biphenyl-adapted microbial communities. Growth of microorganisms was stimulated by incubating soil and sediment samples from polluted and nonpolluted sites with biphenyl crystals. After 6 months, stable population densities between 8 {times} 10{sup 9} and 2 {times} 10{sup 11} CFU/ml were established in the microcosms, and a large percentage of the organisms were able to grow on biphenyl-containing minimal medium plates. A total of 177 biphenyl-degrading strains were subsequently isolated and characterized by their ability to grow on biphenyl in liquid culture and to accumulate a yellow meta cleavage product when they were sprayed with dihydroxy-biphenyl. Isolates were identified by using a polyphasic approach, including fatty acid methyl ester (FAME) analysis, 16S rRNA gene sequence comparison, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins, and genomic fingerprinting based on sequence variability in the 16S-23S ribosomal DNA intergenic spacer region. In all of the microcosms, isolates identified as Rhodococcus opacus dominated the cultivable microbial community, comprising a cluster of 137 isolates with very similar FAME profiles (Euclidean distances, <10) and identical 16S rRNA gene sequences.

  18. Microcosm for assessing survival of genetically engineered microorganisms in aquatic environments

    SciTech Connect

    Awong, J.; Bitton, G.; Chaudhry, G.R. )

    1990-04-01

    Laboratory-contained microcosms are important for studying the fate and survival of genetically engineered microorganisms. In this study, we describe a simple aquatic microcosm that utilizes survival chambers in a flow through or static renewal system. The model was used to study the survival of genetically engineered and wild-type strains of Escherichia coli and Pseudomonas putida in the lake water environment. Temperature-dependent studies indicated that the genetically engineered microorganisms survived better or at least as well as their wild-type counterparts at 15, 25, and 30{degree}C. The genetic determinants of the genetically engineered microorganisms also remained fairly stable within the host cell under the tested conditions. In the presence of organisms indigenous to lake water, E. coli was eliminated after 20 days, whereas P. putida showed an initial decline but was able to stabilize its population after 5 days. A herbicide, Hydrothol-191, caused a significant decline in numbers of P. putida, but no significant difference was observed between the genetically engineered microorganisms and the wild-type strain. The microcosm described is simple, can be easily adapted to study a variety of environmental variables, and has the advantage that the organisms tested are constantly exposed to test waters that are continuously renewed.

  19. Impact of Roundup on the marine microbial community, as shown by an in situ microcosm experiment.

    PubMed

    Stachowski-Haberkorn, Sabine; Becker, Beatriz; Marie, Dominique; Haberkorn, Hansy; Coroller, Louis; de la Broise, Denis

    2008-09-29

    The effects of the herbicide Roundup (glyphosate) on natural marine microbial communities were assessed in a 7-day field experiment using microcosms. Bottles were maintained underwater at 6m depth, and 10% of their water content was changed every other day. The comparison of control microcosms and surrounding surface water showed that the microcosm system tested here can be considered as representative of the natural surrounding environment. A temporal temperature gradient gel electrophoresis (TTGE) was run on 16S and 18S rDNA-amplified extracts from the whole microbial community. Cluster analysis of the 16S gel showed differences between control and treatment fingerprints for Roundup at 1 microg L(-1) (ANOSIM, p=0.055; R=0.53), and 10 microg L(-1) (ANOSIM, p=0.086; R=0.40). Flow cytometry analysis revealed a significant increase in the prasinophyte-like population when Roundup concentration was increased to 10 microg L(-1). This study demonstrates that a disturbance was caused to the marine microbial community exposed to 1 microg L(-1) Roundup concentration, a value typical of those reported in coastal waters during a run-off event. PMID:18760491

  20. Gonadal development of larval male Xenopus laevis exposed to atrazine in outdoor microcosms

    USGS Publications Warehouse

    Jooste, A.M.; Du Preez, L.H.; Carr, J.A.; Giesy, J.P.; Gross, T.S.; Kendall, R.J.; Smith, E.E.; Van Der Kraak, G. L.; Solomon, K.R.

    2005-01-01

    The potential effects of atrazine on gonadal development in metamorphs and subadults of the African clawed frog (Xenopus laevis) were studied under conditions of natural photoperiod and temperatures in outdoor microcosms from August 2002 to June 2003 in South Africa. Triplicate 1100 L microcosms for each nominal concentration of 0.0, 1, 10, and 25 ??g of atrazine/L were used. Measured atrazine concentrations varied <25% throughout the study, and no atrazine was detected in the control microcosms. Tadpoles developed well at all concentrations. On the basis of histological examination of testes of recently metamorphosed stage 66 frogs, 57% of the individuals in the reference group exhibited testicular oocytes as compared with 57, 59, and 39% of the 1, 10, and 25 ??g/L atrazine groups, respectively. The average prevalence of testicular oocytes for all of the treatments including the controls was 54% in a single testis, while, in 35% of individuals, testicular oocytes were observed in both testes. The number of testicular oocytes per individual ranged from 0 to 58 with means of 9.5, 9.8, 8.5, and 11.1 for the 0.0, 1, 10, and 25 ??g of atrazine/L groups, respectively. Ten months after metamorphosis, another subset of juveniles was examined, and the maximum number of testicular oocytes observed was five in one animal. The presence of testicular oocytes was not related to exposure to atrazine and may be a natural phenomenon during ontogeny. ?? 2005 American Chemical Society.

  1. Jarosite-related chemical processes and water ecotoxicity in simplified anaerobic microcosm wetlands

    NASA Astrophysics Data System (ADS)

    Zhu, L.; Lin, C.; Wu, Y.; Lu, W.; Liu, Y.; Ma, Y.; Chen, A.

    2008-02-01

    Simulation experiments were conducted to examine whether jarosite is decomposed and toxic products are produced under anaerobic microcosm wetland conditions. The results show that jarosite was stable under water inundation in the microcosm wetland for a period of at least 56 days when no organic substance was added. However, jarosite became increasingly unstable with increasing amount of added organic matter. This resulted in entry of ferrous Fe into the soil solutions. Concentration of other heavy metals in the leachates was extremely low except for Mn. This is attributed to the maintenance of a high pH in the microcosm wetlands, which might cause re-precipitation of originally jarosite-borne heavy metals, if any. No acute toxicity was observed for leachate from the control (non organic matter-added treatment). However, leachates from various organic matter-added treatments show varying degrees of toxicity to the test organism and soluble Fe was likely to be the dominant metal of potential toxicity. Atmospheric exposure of leachate led to oxidation of ferrous Fe and precipitation of iron hydroxide, which caused a drop in leachate pH. This, in turn, inhibited further oxidation of ferrous Fe.

  2. The use of outdoor freshwater pond microcosms. III. Responses of phytoplankton and periphyton to pyridaben

    USGS Publications Warehouse

    Ross, R.M.; Krise, W.F.; Redell, L.A.; Bennett, R.M.

    2001-01-01

    An outdoor freshwater microcosm study was conducted in which pyridaben, an insecticide-miticide, was directly applied to water to determine its biological effects on phytoplankton and periphyton. Twenty-four microcosms (24 m3 each) were monitored for 11 months, then four treatments of pyridaben were applied two times at three concentrations (0.34, 34.0 ??g/L), including an untreated control. The succession of algal groups observed and the major genera found in microcosms during the baseline phase of the study were typical of oligo-mesotrophic systems in Florida. Following application of pyridaben, the most remarkable effect was a positive correlation of phytoplankton abundance with pyridaben concentrations in water; indicating increased abundance as a result of exposure. Both Chlorophyta and Pyrrophyta exhibited a significant increase (p=0.05) in population abundance at 3.4 and 34.0 ??g/L pyridaben. Chrysophyta also elicited a trend of increased abundance at 34.0 ??g/L, although the effect was not significant. The effects on phytoplankton populations were associated with the decline of zooplankton populations as a result of a direct effect of pyridaben exposure. There were no effects of pyridaben on periphyton communities or on functional endpoints. ?? 2001 by John Wiley & Sons, Inc.

  3. Effects of intact versus non-intact families on adolescent head injury rehabilitation.

    PubMed

    Barry, P; Clark, D

    1992-01-01

    Forty-one children, aged 8-18 years, were admitted to a comprehensive in-patient head injury rehabilitation facility over a 5-year period. Over half (59%) came from families with only one biological parent in the home. Data from intact versus non-intact families suggest that the children from the latter were significantly younger and remained as in-patients significantly longer than their counterparts. The severity of injuries and incidence of premorbid psychosocial documentation were equivalent for the two groups. The implications for treatment and future research are discussed. A previous version of this paper was presented at the 97th convention of the American Psychological Association in New Orleans on August 13, 1989. The authors are grateful to Dr Mark Ylvisaker for his comments and suggestions. PMID:1581746

  4. 33. TURBINE HALL, ORIGINAL TURBO GENERATOR, INTACT CONDENSER Philadelphia ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. TURBINE HALL, ORIGINAL TURBO GENERATOR, INTACT CONDENSER - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  5. Development of a novel immunoassay specific for mouse intact proinsulin.

    PubMed

    Imai, Sunao; Takahashi, Tatsuya; Naito, Shoichi; Yamauchi, Akira; Okada, Chihiro; Notsu, Yoshihide; Sakikawa, Ikue; Hatanaka, Michiyoshi; Iwasaki, Takanori; Morita, Atsushi; Fujii, Ikuo; Yamane, Shoji

    2015-09-01

    The blood concentration of intact proinsulin, but not total proinsulin, has been suggested to be a diagnostic marker for type 2 diabetes mellitus (T2DM), but a sensitive assay specific for rodent intact proinsulin is lacking. Here, a novel enzyme-linked immunosorbent assay (ELISA) for mouse intact proinsulin was developed. The developed ELISA detected mouse intact proinsulin with the working range of 8.3 to 2700pg/ml. Cross-reactivity with mouse split-32,33 proinsulin was approximately 100times lower than the reactivity with mouse intact proinsulin, and no cross-reactivity with mouse insulin was detected. The developed ELISA was sufficiently sensitive to detect low levels of intact proinsulin in normal mouse plasma. The measurement by the developed ELISA revealed that intact proinsulin was elevated in the plasma of type 2 diabetic db/db mice as mice aged, and the ratio of intact proinsulin/insulin in plasma was correlated with levels of glycated hemoglobin A1c as seen in T2DM patients. These results suggest that the plasma level of intact proinsulin, but not total proinsulin, is a sensitive marker for pancreatic dysfunction and the ensuring diabetic disease progression of db/db mice. This ELISA could aid nonclinical evaluation of therapeutic interventions in T2DM. PMID:26026387

  6. Nitrite Uptake into Intact Pea Chloroplasts 1

    PubMed Central

    Brunswick, Pamela; Cresswell, Christopher F.

    1988-01-01

    The relationship between net nitrite uptake and its reduction in intact pea chloroplasts was investigated employing electron transport regulators, uncouplers, and photophosphorylation inhibitors. Observations confirmed the dependence of nitrite uptake on stromal pH and nitrite reduction but also suggested a partial dependance upon PSI phosphorylation. It was also suggested that ammonia stimulates nitrogen assimilation in the dark by association with stromal protons. Inhibition of nitrite uptake by N-ethylmaleimide and dinitrofluorobenzene could not be completely attributed to their inhibition of carbon dioxide fixation. Other protein binding reagents which inhibited photosynthesis showed no effect on nitrite uptake, except for p-chlormercuribenzoate which stimulated nitrite uptake. The results with N-ethylmaleimide and dinitrofluorobenzene tended to support the proposed presence of a protein permeation channel for nitrite uptake in addition to HNO2 penetration. On the basis of a lack of effect by known anion uptake inhibitors, it was concluded that the nitrite uptake mechanism was distinct from that of phosphate and chloride/sulfate transport. PMID:16665917

  7. Uranium migration through intact sandstone cores

    NASA Astrophysics Data System (ADS)

    Read, D.; Lawless, T. A.; Sims, R. J.; Butter, K. R.

    1993-06-01

    Uranium is often considered to be a mobile radioelement in the natural environment owing to its tendency to form stable complexes with a number of aqueous anions, particularly in oxidising milieu. A series of infiltration experiments were devised to investigate this migration behaviour under rigidly controlled laboratory conditions. Intact cores of Permo-Triassic Clashach Sandstone were pre-equilibrated with synthetic groundwater solutions and continuous flow-through of uranium monitored together with pH and concentrations of other ions. Prior to performing each experiment a simulation was carried out using a one-dimensional coupled chemical transport code, encompassing a thermodynamic description of the electrical double layer. These calculations together with electron microscopy indicated the potential role played by iron oxyhydroxide grain coatings in retarding the uranium plume. Thus, a second series of experiments was initiated on pre-acidified cores from which all surface exposed iron had been removed, allowing an assessment of the retention capacity of non-ferric components. Taken together, the data clearly illustrate the strong affinity of aqueous uranium species for natural surfaces even under strongly oxidising conditions. The success of the model in predicting a priori the dominant trends in uranium migration behaviour is encouraging and may aid in prioritising analytical requirements for investigations in more complex geochemical situations than those studied here.

  8. Teaching basic neurophysiology using intact earthworms.

    PubMed

    Kladt, Nikolay; Hanslik, Ulrike; Heinzel, Hans-Georg

    2010-01-01

    Introductory neurobiology courses face the problem that practical exercises often require expensive equipment, dissections, and a favorable student-instructor ratio. Furthermore, the duration of an experiment might exceed available time or the level of required expertise is too high to successfully complete the experiment. As a result, neurobiological experiments are commonly replaced by models and simulations, or provide only very basic experiments, such as the frog sciatic nerve preparation, which are often time consuming and tedious. Action potential recordings in giant fibers of intact earthworms (Lumbricus terrestris) circumvent many of these problems and result in a nearly 100% success rate. Originally, these experiments were introduced as classroom exercises by Charles Drewes in 1978 using awake, moving earthworms. In 1990, Hans-Georg Heinzel described further experiments using anesthetized earthworms. In this article, we focus on the application of these experiments as teaching tools for basic neurobiology courses. We describe and extend selected experiments, focusing on specific neurobiological principles with experimental protocols optimized for classroom application. Furthermore, we discuss our experience using these experiments in animal physiology and various neurobiology courses at the University of Bonn. PMID:23494516

  9. Teaching Basic Neurophysiology Using Intact Earthworms

    PubMed Central

    Kladt, Nikolay; Hanslik, Ulrike; Heinzel, Hans-Georg

    2010-01-01

    Introductory neurobiology courses face the problem that practical exercises often require expensive equipment, dissections, and a favorable student-instructor ratio. Furthermore, the duration of an experiment might exceed available time or the level of required expertise is too high to successfully complete the experiment. As a result, neurobiological experiments are commonly replaced by models and simulations, or provide only very basic experiments, such as the frog sciatic nerve preparation, which are often time consuming and tedious. Action potential recordings in giant fibers of intact earthworms (Lumbricus terrestris) circumvent many of these problems and result in a nearly 100% success rate. Originally, these experiments were introduced as classroom exercises by Charles Drewes in 1978 using awake, moving earthworms. In 1990, Hans-Georg Heinzel described further experiments using anesthetized earthworms. In this article, we focus on the application of these experiments as teaching tools for basic neurobiology courses. We describe and extend selected experiments, focusing on specific neurobiological principles with experimental protocols optimized for classroom application. Furthermore, we discuss our experience using these experiments in animal physiology and various neurobiology courses at the University of Bonn. PMID:23494516

  10. Vitrification of intact human articular cartilage.

    PubMed

    Jomha, Nadr M; Elliott, Janet A W; Law, Garson K; Maghdoori, Babak; Forbes, J Fraser; Abazari, Alireza; Adesida, Adetola B; Laouar, Leila; Zhou, Xianpei; McGann, Locksley E

    2012-09-01

    Articular cartilage injuries do not heal and large defects result in osteoarthritis with major personal and socioeconomic costs. Osteochondral transplantation is an effective treatment for large joint defects but its use is limited by the inability to store cartilage for long periods of time. Cryopreservation/vitrification is one method to enable banking of this tissue but decades of research have been unable to successfully preserve the tissue while maintaining cartilage on its bone base - a requirement for transplantation. To address this limitation, human knee articular cartilage from total knee arthroplasty patients and deceased donors was exposed to specified concentrations of 4 different cryoprotective agents for mathematically determined periods of time at lowering temperatures. After complete exposure, the cartilage was immersed in liquid nitrogen for up to 3 months. Cell viability was 75.4 ± 12.1% determined by membrane integrity stains and confirmed with a mitochondrial assay and pellet culture documented production of sulfated glycosaminoglycans and collagen II similar to controls. This report documents successful vitrification of intact human articular cartilage on its bone base making it possible to bank this tissue indefinitely. PMID:22698720

  11. Population dynamics of transgenic strain Escherichia coli Z905/pPHL7 in freshwater and saline lake water microcosms with differing microbial community structures

    NASA Technical Reports Server (NTRS)

    Popova, L. Yu; Kargatova, T. V.; Ganusova, E. E.; Lobova, T. I.; Boyandin, A. N.; Mogilnaya, O. A.; Pechurkin, N. S.

    2005-01-01

    Populations of Escherichia coli Z905/pPHL7, a transgenic microorganism, were heterogenic in the expression of plasmid genes when adapting to the conditions of water microcosms of various mineralization levels and structure of microbial community. This TM has formed two subpopulations (ampicillin-resistant and ampicillin-sensitive) in every microcosm. Irrespective of mineralization level of a microcosm, when E. coli Z905/pPHL7 alone was introduced, the ampicillin-resistant subpopulation prevailed, while introduction of the TM together with indigenous bacteria led to the dominance of the ampicillin-sensitive subpopulation. A high level of lux gene expression maintained longer in the freshwater microcosms than in sterile saline lake water microcosms. A horizontal gene transfer has been revealed between the jointly introduced TM and Micrococcus sp. 9/pSH1 in microcosms with the Lake Shira sterile water. c2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

  12. Population dynamics of transgenic strain Escherichia coli Z905/pPHL7 in freshwater and saline lake water microcosms with differing microbial community structures

    NASA Astrophysics Data System (ADS)

    Popova, L. Yu.; Kargatova, T. V.; Ganusova, E. E.; Lobova, T. I.; Boyandin, A. N.; Mogilnaya, O. A.; Pechurkin, N. S.

    Populations of Escherichia coli Z905/pPHL7, a transgenic microorganism, were heterogenic in the expression of plasmid genes when adapting to the conditions of water microcosms of various mineralization levels and structure of microbial community. This TM has formed two subpopulations (ampicillin-resistant and ampicillin-sensitive) in every microcosm. Irrespective of mineralization level of a microcosm, when E. coli Z905/pPHL7 alone was introduced, the ampicillin-resistant subpopulation prevailed, while introduction of the TM together with indigenous bacteria led to the dominance of the ampicillin-sensitive subpopulation. A high level of lux gene expression maintained longer in the freshwater microcosms than in sterile saline lake water microcosms. A horizontal gene transfer has been revealed between the jointly introduced TM and Micrococcus sp. 9/pSH1 in microcosms with the Lake Shira sterile water.

  13. Positive Youth Development, Life Satisfaction, and Problem Behaviors of Adolescents in Intact and Non-Intact Families in Hong Kong

    PubMed Central

    Shek, Daniel T. L.; Leung, Hildie

    2013-01-01

    This study investigated whether Chinese adolescents living in intact and non-intact families differed in their positive development, life satisfaction, and risk behavior. A total of 3,328 Secondary 1 students responded to measures of positive youth development (such as resilience and psychosocial competencies), life satisfaction, and risk behavior (substance abuse, delinquency, Internet addiction, consumption of pornographic materials, self-harm, and behavioral intention to engage in problem behavior). Findings revealed that adolescents growing up in intact families reported higher levels of positive developmental outcomes and life satisfaction as compared with adolescents from non-intact families. Adolescents in non-intact families also reported higher levels of risk behaviors than those growing up in intact families. PMID:24400264

  14. Influence of sediment on the fate and toxicity of a polyethoxylated tallowamine surfactant system (MON 0818) in aquatic microcosms

    USGS Publications Warehouse

    Wang, N.; Besser, J.M.; Buckler, D.R.; Honegger, J.L.; Ingersoll, C.G.; Johnson, B.T.; Kurtzweil, M.L.; MacGregor, J.; McKee, M.J.

    2005-01-01

    The fate and toxicity of a polyethoxylated tallowamine (POEA) surfactant system, MON 0818, was evaluated in water-sediment microcosms during a 4-d laboratory study. A surfactant solution of 8 mg l-1 nominal concentration was added to each of nine 72-l aquaria with or without a 3-cm layer of one of two natural sediments (total organic carbon (TOC) 1.5% or 3.0%). Control well water was added to each of nine additional 72-l aquaria with or without sediment. Water samples were collected from the microcosms after 2, 6, 24, 48, 72, and 96 h of aging to conduct 48-h toxicity tests with Daphnia magna and to determine surfactant concentrations. Elevated mortality of D. magna (43-83%) was observed in overlying water sampled from water-only microcosms throughout the 96-h aging period, whereas elevated mortality (23-97%) was only observed in overlying water sampled from water-sediment microcosms during the first 24 h of aging. Measured concentrations of MON 0818 in water-only microcosms remained relatively constant (4-6 mg l-1) during the 96-h period, whereas the concentrations in overlying water from microcosms containing either of the two types of sediment dissipated rapidly, with half-lives of 13 h in the 3.0% TOC sediment and 18 h in the 1.5% TOC sediment. Both toxicity and the concentration of MON 0818 in overlying water decreased more rapidly in microcosms containing sediment with the higher percent TOC and clay and with a higher microbial biomass. Mortality of D. magna was significantly correlated with surfactant concentrations in the overlying water. These results indicate that the toxicity of the POEA surfactant in water rapidly declines in the presence of sediment due to a reduction in the surfactant concentration in the overlying water above the sediment.

  15. 50 CFR 622.247 - Landing golden crab intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing golden crab intact. 622.247... ATLANTIC Golden Crab Fishery of the South Atlantic Region § 622.247 Landing golden crab intact. The operator of a vessel that fishes in the EEZ is responsible for ensuring that golden crab on that vessel...

  16. 50 CFR 622.247 - Landing golden crab intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing golden crab intact. 622.247... ATLANTIC Golden Crab Fishery of the South Atlantic Region § 622.247 Landing golden crab intact. The operator of a vessel that fishes in the EEZ is responsible for ensuring that golden crab on that vessel...

  17. 50 CFR 622.493 - Landing Caribbean queen conch intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing Caribbean queen conch intact. 622... ATLANTIC Queen Conch Resources of Puerto Rico and the U.S. Virgin Islands § 622.493 Landing Caribbean queen conch intact. (a) A Caribbean queen conch in or from the Caribbean EEZ must be maintained with meat...

  18. 50 CFR 622.493 - Landing Caribbean queen conch intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing Caribbean queen conch intact. 622... ATLANTIC Queen Conch Resources of Puerto Rico and the U.S. Virgin Islands § 622.493 Landing Caribbean queen conch intact. (a) A Caribbean queen conch in or from the Caribbean EEZ must be maintained with meat...

  19. 50 CFR 622.38 - Landing fish intact.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Landing fish intact. 622.38 Section 622.38... Landing fish intact. The operator of a vessel that fishes in the EEZ is responsible for ensuring that fish... specified in paragraphs (c) and (d) of this section. Such fish may be eviscerated, gilled, and scaled,...

  20. 50 CFR 622.455 - Landing spiny lobster intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing spiny lobster intact. 622.455... ATLANTIC Spiny Lobster Fishery of Puerto Rico and the U.S. Virgin Islands § 622.455 Landing spiny lobster intact. (a) A Caribbean spiny lobster in or from the Caribbean EEZ must be maintained with head...

  1. 50 CFR 622.455 - Landing spiny lobster intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing spiny lobster intact. 622.455... ATLANTIC Spiny Lobster Fishery of Puerto Rico and the U.S. Virgin Islands § 622.455 Landing spiny lobster intact. (a) A Caribbean spiny lobster in or from the Caribbean EEZ must be maintained with head...

  2. 46 CFR 170.165 - International Code on Intact Stability.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false International Code on Intact Stability. 170.165 Section... STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS Intact Stability Criteria § 170.165 International Code on...) through (4) of this section, must comply with the Introduction and Part A of the International Code...

  3. 46 CFR 170.165 - International Code on Intact Stability.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false International Code on Intact Stability. 170.165 Section... STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS Intact Stability Criteria § 170.165 International Code on...) through (4) of this section, must comply with the Introduction and Part A of the International Code...

  4. 46 CFR 170.165 - International Code on Intact Stability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false International Code on Intact Stability. 170.165 Section... STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS Intact Stability Criteria § 170.165 International Code on...) through (4) of this section, must comply with the Introduction and Part A of the International Code...

  5. 46 CFR 170.165 - International Code on Intact Stability.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false International Code on Intact Stability. 170.165 Section... STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS Intact Stability Criteria § 170.165 International Code on...) through (4) of this section, must comply with the Introduction and Part A of the International Code...

  6. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  7. 46 CFR 174.045 - Intact stability requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Intact stability requirements. 174.045 Section 174.045 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Mobile Offshore Drilling Units § 174.045 Intact stability requirements. (a)...

  8. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  9. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  10. 50 CFR 622.186 - Landing fish intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing fish intact. 622.186 Section 622...-Grouper Fishery of the South Atlantic Region § 622.186 Landing fish intact. (a) South Atlantic snapper... specified in paragraph (b) of this section. Such fish may be eviscerated, gilled, and scaled, but...

  11. 50 CFR 622.186 - Landing fish intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing fish intact. 622.186 Section 622...-Grouper Fishery of the South Atlantic Region § 622.186 Landing fish intact. (a) South Atlantic snapper... specified in paragraph (b) of this section. Such fish may be eviscerated, gilled, and scaled, but...

  12. 50 CFR 622.10 - Landing fish intact--general.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH... landing fish intact that are broadly applicable to finfish in the Gulf EEZ and Caribbean EEZ, as specified... intact. (a) Finfish in or from the Gulf EEZ or Caribbean EEZ, except as specified in paragraphs (b)...

  13. 50 CFR 622.10 - Landing fish intact--general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH... landing fish intact that are broadly applicable to finfish in the Gulf EEZ and Caribbean EEZ, as specified... intact. (a) Finfish in or from the Gulf EEZ or Caribbean EEZ, except as specified in paragraphs (b)...

  14. Assessing microbial responses to iron enrichment in the Subarctic Northeast Pacific: Do microcosms reproduce the in situ condition?

    NASA Astrophysics Data System (ADS)

    Scarratt, M. G.; Marchetti, A.; Hale, M. S.; Rivkin, R. B.; Michaud, S.; Matthews, P.; Levasseur, M.; Sherry, N.; Merzouk, A.; Li, W. K. W.; Kiyosawa, H.

    2006-10-01

    A microcosm experiment was conducted in the NE Pacific in July 2002 to compare the microbial response between microcosms and the Subarctic Ecosystem Response to Iron-Enrichment Study (SERIES) in situ iron-enrichment experiment. Seawater microcosms (20 L) were incubated aboard ship under natural light using three treatments: (1) low-iron seawater amended with 4 nmol l -1 FeSO 4 (+Fe); (2) low-iron seawater amended with 4 nmol l -1 FeSO 4 and 86 nmol l -1 GeO 2 (+Fe+Ge); (3) seawater collected from the in situ Fe-enriched patch (PW). The +Fe+Ge treatment used germanium to control diatom growth to assess the role of diatoms in dimethylsulfoniopropionate (DMSP) production. The following variables were measured in the microcosms and in situ: chlorophyll a (chl a), nitrate ( NO3-), silicic acid (Si(OH) 4), phytoplankton abundance and species identification, bacterial abundance (including estimates of low- and high-DNA bacteria), bacterial production, bacterial specific growth rate, particulate and dissolved DMSP and dimethylsulfide (DMS) concentrations. There was little or no significant difference (ANCOVA) in the response of most variables between the +Fe and PW microcosms, but large differences were observed between both these treatments and the in situ data from the enriched patch. Chl a in all microcosms increased from ambient levels (approx. 0.5-1 μg l -1) to approx. 4.5-6.2 μg l -1 after 11 d incubation, when NO3- was fully depleted from all microcosms. During this same period, in situ chl a increased more slowly to a maximum of 2.9 μg l -1 on day 11. Nanophytoplankton and picophytoplankton were more abundant in the microcosms relative to the in situ community, which became dominated by large diatoms. Bacterial abundance was similar in the microcosms and in situ, but bacterial production was significantly higher in the microcosms. While neither DMSP d nor DMS accumulation showed significant differences between the microcosms and in situ , particulate DMSP

  15. U(VI) bioreduction with emulsified vegetable oil as the electron donor-- Microcosm tests and model development

    SciTech Connect

    Tang, Guoping; Wu, Wei-min; Watson, David B; Parker, Jack C.; Schadt, Christopher Warren; Brooks, Scott C; Shi, Xiaoqing

    2013-01-01

    Microcosm tests were conducted to study U(VI) bioreduction in contaminated sediments with emulsified vegetable oil (EVO) as the electron donor. In the microcosms, EVO was degraded by indigenous microorganisms and stimulated Fe, U, and sulfate bioreduction, and methanogenesis. Removal of aqueous U occurred concurrently with sulfate reduction, with more reduction of total U in the case of higher initial sulfate concentrations. X-ray absorption near-edge spectroscopy (XANES) analysis confirmed U(VI) reduction to U(IV). As the acetate concentration peaked in 10~20 days in oleate microcosms, the maximum was reached in 100~120 days in the EVO microcosms, indicating that EVO hydrolysis was rate-limiting. The acetate accumulation was sustained over 50 days longer in the oleate and EVO than in the ethanol microcosms, suggesting that acetate-utilizing methanogenesis was slower in the cases of oleate and EVO. Both slow hydrolysis and methanogenesis could contribute to potential sustained bioreduction in field application. Biogeochemical models were developed to couple degradation of EVO, production and oxidation of long-chain fatty acids, glycerol, acetate, and hydrogen, reduction of Fe(III), U(VI) and sulfate, and methanogenesis with growth and decay of microbial functional groups. The models were used to simulate the coupled processes in a field test in a companion article.

  16. Donor-dependent Extent of Uranium Reduction for Bioremediation of Contaminated Sediment Microcosms

    SciTech Connect

    Palumbo, Anthony Vito; Ravel, Bruce; Phelps, Tommy Joe; Schadt, Christopher Warren; Brandt, Craig C

    2009-01-01

    Bioremediation of uranium was investigated in microcosm experiments containing contaminated sediments from Oak Ridge, Tennessee to explore the importance of electron donor selection for uranium reduction rate and extent. In these experiments, all of the electron donors, including ethanol, glucose, methanol, and methanol with added humic acids, stimulated the reduction and immobilization of aqueous uranium by the indigenous microbial community. Uranium loss from solution began after the completion of nitrate reduction but essentially concurrent with sulfate reduction. When electron donor concentrations were normalized for their equivalent electron donor potential yield, the rates of uranium reduction were nearly equivalent for all treatments (0.55-0.95 {micro}mol L{sup -1} d{sup -1}). Uranium reduction with methanol proceeded after a 15-d longer lag time relative to that of ethanol or glucose. Significant differences were not found with the inclusion of humic acids. The extent of U reduction in sediment slurries measured by XANES at various time periods after the start of the experiment increased in the order of ethanol (5-7% reduced at 77 and 153 d), glucose (49% reduced at 53 d), and methanol (93% reduced at 90 d). The microbial diversity of ethanol- and methanol-amended microcosms in their late stage of U reduction was analyzed with 16S rRNA gene amplification. Members of the Geobacteraceae were found in all microcosms as well as other potential uranium-reducing organisms, such as Clostridium and Desulfosporosinus. The effectiveness of methanol relative to ethanol at reducing aqueous and sediment-hosted uranium suggests that bioremediation strategies that encourage fermentative poising of the subsurface to a lower redox potential may be more effective for long-term uranium immobilization as compared with selecting an electron donor that is efficiently metabolized by known uranium-reducing microorganisms.

  17. Donor-dependent Extent of Uranium Reduction for Bioremediation of Contaminated Sediment Microcosms

    SciTech Connect

    Madden, Andrew S.; Palumbo, Anthony V.; Ravel, Bruce; Vishnivetskaya, Tatiana A.; Phelps, Tommy J.; Schadt, Christopher W.; Brandt, Craig C.

    2009-03-16

    Bioremediation of uranium was investigated in microcosm experiments containing contaminated sediments from Oak Ridge, Tennessee to explore the importance of electron donor selection for uranium reduction rate and extent. In these experiments, all of the electron donors, including ethanol, glucose, methanol, and methanol with added humic acids, stimulated the reduction and immobilization of aqueous uranium by the indigenous microbial community. Uranium loss from solution began after the completion of nitrate reduction but essentially concurrent with sulfate reduction. When electron donor concentrations were normalized for their equivalent electron donor potential yield, the rates of uranium reduction were nearly equivalent for all treatments (0.55-0.95 {micro}mol L{sup -1} d{sup -1}). Uranium reduction with methanol proceeded after a 15-d longer lag time relative to that of ethanol or glucose. Significant differences were not found with the inclusion of humic acids. The extent of U reduction in sediment slurries measured by XANES at various time periods after the start of the experiment increased in the order of ethanol (5-7% reduced at 77 and 153 d), glucose (49% reduced at 53 d), and methanol (93% reduced at 90 d). The microbial diversity of ethanol- and methanol-amended microcosms in their late stage of U reduction was analyzed with 16S rRNA gene amplification. Members of the Geobacteraceae were found in all microcosms as well as other potential uranium-reducing organisms, such as Clostridium and Desulfosporosinus. The effectiveness of methanol relative to ethanol at reducing aqueous and sediment-hosted uranium suggests that bioremediation strategies that encourage fermentative poising of the subsurface to a lower redox potential may be more effective for long-term uranium immobilization as compared with selecting an electron donor that is efficiently metabolized by known uranium-reducing microorganisms.

  18. Factors Influencing TCE Anaerobic Dechlorination Investigated via Simulations of Microcosm Experiments

    NASA Astrophysics Data System (ADS)

    Mao, X.; Harkness, M.; Lee, M. D.; Mack, E. E.; Dworatzek, S.; Acheson, C.; McCarty, P.; Barry, D. A.; Gerhard, J. I.

    2006-12-01

    SABRE (Source Area BioREmediation) is a public-private consortium whose charter is to determine if enhanced anaerobic bioremediation can result in effective and quantifiable treatment of chlorinated solvent DNAPL source areas. The focus of this 4-year, $5.7 million research project is a field site in the United Kingdom containing a TCE DNAPL source area. In preparation, a microcosm study was performed to determine the optimal combination of factors to support reductive dechlorination of TCE in site soil and groundwater. The study consisted of 168 bottles distributed between four laboratories (Dupont, GE, SiREM, and Terra Systems) and tested the impact of six carbon substrates (lactate, acetate, methanol, SRS (soybean oil), hexanol, butyl acetate), bioaugmentation with KB-1 bacterial culture, three TCE levels (100 mg/L, 400 mg/L, and 800 mg/L) and two sulphate levels (200 mg/L, >500 mg/L) on TCE dechlorination. This research presents a numerical model designed to simulate the main processes occurring in the microcosms, including substrate fermentation, sequential dechlorination, toxic inhibition, and the influence of sulphate concentration. In calibrating the model to over 60 of the microcosm experiments, lumped parameters were employed to quantify the effect of key factors on the conversion rate of each chlorinated ethene in the TCE degradation sequence. Results quantify the benefit (i.e., increased stepwise dechlorination rate) due to both bioaugmentation and the presence of higher sulphate concentrations. Competitive inhibition is found to increase in significance as TCE concentrations increase; however, inclusion of Haldane inhibition is not supported. Over a wide range of experimental conditions and dechlorination steps, SRS appears to induce relatively little hydrogen limitation, thereby facilitating relatively quick conversion of TCE to ethene. In general, hydrogen limitation is found to increase with increasing TCE concentration and with bioaugmentation, and

  19. Plasmid Transfer between Spatially Separated Donor and Recipient Bacteria in Earthworm-Containing Soil Microcosms

    PubMed Central

    Daane, L. L.; Molina, J.; Sadowsky, M. J.

    1997-01-01

    Most gene transfer studies have been performed with relatively homogeneous soil systems in the absence of soil macrobiota, including invertebrates. In this study we examined the influence of earthworm activity (burrowing, casting, and feeding) on transfer of plasmid pJP4 between spatially separated donor (Alcaligenes eutrophus) and recipient (Pseudomonas fluorescens) bacteria in nonsterile soil columns. A model system was designed such that the activity of earthworms would act to mediate cell contact and gene transfer. Three different earthworm species (Aporrectodea trapezoides, Lumbricus rubellus, and Lumbricus terrestris), representing each of the major ecological categories (endogeic, epigeic, and anecic), were evaluated. Inoculated soil microcosms, with and without added earthworms, were analyzed for donor, recipient, and transconjugant bacteria at 5-cm-depth intervals by using selective plating techniques. Transconjugants were confirmed by colony hybridization with a mer gene probe. The presence of earthworms significantly increased dispersal of the donor and recipient strains. In situ gene transfer of plasmid pJP4 from A. eutrophus to P. fluorescens was detected only in earthworm-containing microcosms, at a frequency of (symbl)10(sup2) transconjugants per g of soil. The depth of recovery was dependent on the burrowing behavior of each earthworm species; however, there was no significant difference in the total number of transconjugants among the earthworm species. Donor and recipient bacteria were recovered from earthworm feces (casts) of all three earthworm species, with numbers up to 10(sup6) and 10(sup4) bacteria per g of cast, respectively. A. trapezoides egg capsules (cocoons) formed in the inoculated soil microcosms contained up to 10(sup7) donor and 10(sup6) recipient bacteria per g of cocoon. No transconjugant bacteria, however, were recovered from these microhabitats. To our knowledge, this is the first report of gene transfer between physically

  20. Utility of Microcosm Studies for Predicting Phylloplane Bacterium Population Sizes in the Field

    PubMed Central

    Kinkel, L. L.; Wilson, M.; Lindow, S. E.

    1996-01-01

    Population sizes of two ice nucleation-active strains of Pseudomonas syringae were compared on leaves in controlled environments and in the field to determine the ability of microcosm studies to predict plant habitat preferences in the field. The P. syringae strains investigated were the parental strains of recombinant deletion mutant strains deficient in ice nucleation activity that had been field tested for their ability to control plant frost injury. The population size of the P. syringae strains was measured after inoculation at three field locations on up to 40 of the same plant species that were studied in the growth chamber. There was seldom a significant relationship between the mean population size of a given P. syringae strain incubated under either wet or dry conditions in microcosms and the mean population size which could be recovered from the same species when inoculated in the field. Specifically, on some plant species, the population size recovered from leaves in the field was substantially greater than from that species in a controlled environment, while for other plant species field populations were significantly smaller than those observed under controlled conditions. Population sizes of inoculated P. syringae strains, however, were frequently highly positively correlated with the indigenous bacterial population size on the same plant species in the field, suggesting that the ability of a particular plant species to support introduced bacterial strains is correlated with its ability to support large bacterial populations or that indigenous bacteria enhance the survival of introduced strains. Microcosm studies therefore seem most effective at assessing possible differences between parental and recombinant strains under a given environmental regime but are limited in their ability to predict the specific population sizes or plant habitat preferences of bacteria on leaves under field conditions. PMID:16535405

  1. Tracking the Response of Burkholderia cepacia G4 5223-PR1 in Aquifer Microcosms

    PubMed Central

    Winkler, J.; Timmis, K. N.; Snyder, R. A.

    1995-01-01

    The introduction of bacteria into the environment for bioremediation purposes (bioaugmentation) requires analysis and monitoring of microbial population dynamics to define persistence and activity from both efficacy and risk assessment perspectives. Burkholderia cepacia G4 5223-PR1 is a Tn5 insertion mutant which constitutively expresses a toluene ortho-monooxygenase that degrades trichloroethylene (TCE). This ability of G4 5223-PR1 to degrade TCE without aromatic induction may be useful for bioremediation of TCE-containing aquifers and groundwater. Thus, a simulated aquifer sediment system and groundwater microcosms were used to monitor the survival of G4 5223-PR1. The fate of G4 5223-PR1 in sediment was monitored by indirect immunofluorescence microscopy, a colony blot assay, and growth on selective medium. G4 5223-PR1 was detected immunologically by using a highly specific monoclonal antibody which reacted against the O-specific polysaccharide chain of the lipopolysaccharides of this organism. G4 5223-PR1 survived well in sterilized groundwater, although in nonsterile groundwater microcosms rapid decreases in the G4 5223-PR1 cell population were observed. Ten days after inoculation no G4 5223-PR1 cells could be detected by selective plating or immunofluorescence. G4 5223-PR1 survival was greater in a nonsterile aquifer sediment microcosm, although after 22 days of elution the number of G4 5223-PR1 cells was low. Our results demonstrate the utility of monoclonal antibody tracking methods and the importance of biotic interactions in determining the persistence of introduced microorganisms. PMID:16534928

  2. Quick stimulation of Alcanivorax sp. by bioemulsificant EPS₂₀₀₃ on microcosm oil spill simulation.

    PubMed

    Cappello, Simone; Genovese, Maria; Denaro, Renata; Santisi, Santina; Volta, Anna; Bonsignore, Martina; Mancini, Giuseppe; Giuliano, Laura; Genovese, Lucrezia; Yakimov, Michail M

    2014-01-01

    Oil spill microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS₂₀₀₃) on quick stimulation of hydrocarbonoclastic bacteria. Early hours of oil spill, were stimulated using an experimental seawater microcosm, supplemented with crude oil and EPS₂₀₀₃ (SW+OIL+EPS₂₀₀₃); this system was monitored for 2 days and compared to control microcosm (only oil-polluted seawater, SW+OIL). Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out. Community composition of marine bacterioplankton was determined by 16S rRNA gene clone libraries. Data obtained indicated that bioemulsificant addition stimulated an increase of total bacterial abundance and, in particular, selection of bacteria related to Alcanivorax genus; confirming that EPS₂₀₀₃ could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process. PMID:25763036

  3. Reflectance Spectra Comparison of Orbital Debris, Intact Spacecraft, and Intact Rocket Bodies in the GEO Regime

    NASA Technical Reports Server (NTRS)

    Barker, Ed; Abercromby, Kira J.; Abell, Paul

    2009-01-01

    A key objective of NASA s Orbital Debris program office at Johnson Space Center (JSC) is to characterize the debris environment by way of assessing the physical properties (type, mass, density, and size) of objects in orbit. Knowledge of the geosynchronous orbit (GEO) debris environment in particular can be used to determine the hazard probability at specific GEO altitudes and aid predictions of the future environment. To calculate an optical size from an intensity measurement of an object in the GEO regime, a 0.175 albedo is assumed currently. However, identification of specific material type or types could improve albedo accuracy and yield a more accurate size estimate for the debris piece. Using spectroscopy, it is possible to determine the surface materials of space objects. The study described herein used the NASA Infrared Telescope Facility (IRTF) to record spectral data in the 0.6 to 2.5 micron regime on eight catalogued space objects. For comparison, all of the objects observed were in GEO or near-GEO. The eight objects consisted of two intact spacecraft, three rocket bodies, and three catalogued debris pieces. Two of the debris pieces stemmed from Titan 3C transtage breakup and the third is from COSMOS 2054. The reflectance spectra of the Titan 3C pieces share similar slopes (increasing with wavelength) and lack any strong absorption features. The COSMOS debris spectra is flat and has no absorption features. In contrast, the intact spacecraft show classic absorption features due to solar panels with a strong band gap feature near 1 micron. The two spacecraft are spin-stabilized objects and therefore have solar panels surrounding the outer surface. Two of the three rocket bodies are inertial upper stage (IUS) rocket bodies and have similar looking spectra. The slopes flatten out near 1.5 microns with absorption features in the near-infrared that are similar to that of white paint. The third rocket body has a similar flattening of slope but with fewer

  4. Ammonium removal in constructed wetland microcosms as influenced by season and organic carbon load.

    PubMed

    Riley, Kate A; Stein, Otto R; Hook, Paul B

    2005-01-01

    We evaluated ammonium nitrogen removal and nitrogen transformations in three-year-old, batch-operated, subsurface wetland microcosms. Treatments included replicates of Typha latifolia, Carex rostrata, and unplanted controls when influent carbon was excluded, and C. rostrata with an influent containing organic carbon. A series of 10-day batch incubations were conducted over a simulated yearlong cycle of seasons. The presence of plants significantly enhanced ammonium removal during both summer (24 degrees C, active plant growth) and winter (4 degrees C, plant dormancy) conditions, but significant differences between plant species were evident only in summer when C. rostrata outperformed T. latifolia. The effect of organic carbon load was distinctly seasonal, enhancing C. rostrata ammonium removal in winter but having an inhibitory effect in summer. Season did not influence ammonium removal in T. latifolia or unplanted columns. Net production of organic carbon was evident year-round in units without an influent organic carbon source, but was enhanced in summer, especially for C. rostrata, which produced significantly more than T. latifolia and unplanted controls. No differences in production were evident between species in winter. COD values for C. rostrata microcosms with and without influent organic carbon converged within 24 hours in winter and 7 days in summer. Gravel sorption, microbial immobilization and sequential nitrification/denitrification appear to be the major nitrogen removal mechanisms. All evidence suggests differences between season and species are due to differences in seasonal variation of root-zone oxidation. PMID:15921269

  5. Environmental Fate of Chiral Herbicide Fenoxaprop-ethyl in Water-Sediment Microcosms

    NASA Astrophysics Data System (ADS)

    Jing, Xu; Yao, Guojun; Liu, Donghui; Liu, Mingke; Wang, Peng; Zhou, Zhiqiang

    2016-05-01

    The environmental fate of the herbicide fenoxaprop-ethyl (FE) in water, sediment and water-sediment microcosm was studied and degradation products fenoxaprop (FA), ethyl-2-(4-hydroxyphenoxy)propanoate (EHPP), 2-(4-hydroxyphenoxy)propanoic acid (HPPA) and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB) were monitored. FE, FA, EHPP and HPPA were chiral and the environmental behavior was investigated on an enantiomeric level. In water, sediment and water-sediment microcosms, fenoxaprop-ethyl degraded very fast with half-lives less than 1 day and it was found the herbicidally inactive S-enantiomer degraded faster. Fenoxaprop was the main primary degradation product which was quickly formed and the further degradation was relatively slow with half-lives of 6.4–12.4 days, and the S-enantiomer degraded faster too. EHPP, HPPA and CDHB could be found and S-EHPP and S-HPPA were degraded preferentially. The effects of microorganism and water content were investigated and it was found that the enantioselectivity was attributed to microorganisms. In sediment, the main degradation pathway of fenoxaprop-ethyl was hydrolysis and the degradation rate of fenoxaprop-ethyl increased with water content. The degradation products and enantioselectivity should be considered for the impact of fenoxaprop-ethyl on the aquatic system.

  6. Environmental Fate of Chiral Herbicide Fenoxaprop-ethyl in Water-Sediment Microcosms.

    PubMed

    Jing, Xu; Yao, Guojun; Liu, Donghui; Liu, Mingke; Wang, Peng; Zhou, Zhiqiang

    2016-01-01

    The environmental fate of the herbicide fenoxaprop-ethyl (FE) in water, sediment and water-sediment microcosm was studied and degradation products fenoxaprop (FA), ethyl-2-(4-hydroxyphenoxy)propanoate (EHPP), 2-(4-hydroxyphenoxy)propanoic acid (HPPA) and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB) were monitored. FE, FA, EHPP and HPPA were chiral and the environmental behavior was investigated on an enantiomeric level. In water, sediment and water-sediment microcosms, fenoxaprop-ethyl degraded very fast with half-lives less than 1 day and it was found the herbicidally inactive S-enantiomer degraded faster. Fenoxaprop was the main primary degradation product which was quickly formed and the further degradation was relatively slow with half-lives of 6.4-12.4 days, and the S-enantiomer degraded faster too. EHPP, HPPA and CDHB could be found and S-EHPP and S-HPPA were degraded preferentially. The effects of microorganism and water content were investigated and it was found that the enantioselectivity was attributed to microorganisms. In sediment, the main degradation pathway of fenoxaprop-ethyl was hydrolysis and the degradation rate of fenoxaprop-ethyl increased with water content. The degradation products and enantioselectivity should be considered for the impact of fenoxaprop-ethyl on the aquatic system. PMID:27225540

  7. Environmental Fate of Chiral Herbicide Fenoxaprop-ethyl in Water-Sediment Microcosms

    PubMed Central

    Jing, Xu; Yao, Guojun; Liu, Donghui; Liu, Mingke; Wang, Peng; Zhou, Zhiqiang

    2016-01-01

    The environmental fate of the herbicide fenoxaprop-ethyl (FE) in water, sediment and water-sediment microcosm was studied and degradation products fenoxaprop (FA), ethyl-2-(4-hydroxyphenoxy)propanoate (EHPP), 2-(4-hydroxyphenoxy)propanoic acid (HPPA) and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB) were monitored. FE, FA, EHPP and HPPA were chiral and the environmental behavior was investigated on an enantiomeric level. In water, sediment and water-sediment microcosms, fenoxaprop-ethyl degraded very fast with half-lives less than 1 day and it was found the herbicidally inactive S-enantiomer degraded faster. Fenoxaprop was the main primary degradation product which was quickly formed and the further degradation was relatively slow with half-lives of 6.4–12.4 days, and the S-enantiomer degraded faster too. EHPP, HPPA and CDHB could be found and S-EHPP and S-HPPA were degraded preferentially. The effects of microorganism and water content were investigated and it was found that the enantioselectivity was attributed to microorganisms. In sediment, the main degradation pathway of fenoxaprop-ethyl was hydrolysis and the degradation rate of fenoxaprop-ethyl increased with water content. The degradation products and enantioselectivity should be considered for the impact of fenoxaprop-ethyl on the aquatic system. PMID:27225540

  8. Inhibition of nitrate reduction by chromium (VI) in anaerobic soil microcosms

    SciTech Connect

    Kourtev, P. S.; Nakatsu, C. H.; Konopka, Allan

    2009-10-01

    Chromium (VI) is often found as a co-contaminant at sites polluted with organic compounds. We used microcosms amended with glucose or protein, nitrate and increasing concentrations of chromium to study nitrate reduction in Cr(VI) polluted soils. Organic carbon stimulated bacterial activity, but the addition of Cr(VI) caused a lag and then slower rates 5 of CO2 accumulation. Nitrate reduction only occurred after Cr(VI) had been reduced. Bacterial activity was again inhibited when Cr(VI) was added a second time; thus not all Cr-sensitive bacteria were removed in the first phase. Glucose and protein selected for relatively similar bacterial communities, as assayed by PCR-DGGE of the 16S rRNA gene; this selection was modified by the addition of 10 Cr(VI). Cr-resistant bacteria isolated from microcosms were closely related to members of Bacillus, Enterococcus and Propionibacterium sp. Our results indicate that carbon utilization and nitrate reduction in these soils in the presence of Cr(VI) are contingent upon the reduction of the added heavy metal by a limited subset of the bacterial community. The amount of Cr(VI) required to inhibit nitrate reduction was 10-fold less than for aerobic catabolism of the same 15 substrate. We hypothesize that the resistance level of a microbial process is directly related to the diversity of microbes capable of conducting it.

  9. Methane-fed microbial microcosms show differential community dynamics and pinpoint taxa involved in communal response

    PubMed Central

    Oshkin, Igor Y; Beck, David AC; Lamb, Andrew E; Tchesnokova, Veronika; Benuska, Gabrielle; McTaggart, Tami L; Kalyuzhnaya, Marina G; Dedysh, Svetlana N; Lidstrom, Mary E; Chistoserdova, Ludmila

    2015-01-01

    We report observations on the dynamics of bacterial communities in response to methane stimulus in laboratory microcosm incubations prepared with lake sediment samples. We first measured taxonomic compositions of long-term enrichment cultures and determined that, although dominated by Methylococcaceae types, these cultures also contained accompanying types belonging to a limited number of bacterial taxa, methylotrophs and non-methylotrophs. We then followed the short-term community dynamics, in two oxygen tension regimens (150 μM and 15 μM), observing rapid loss of species diversity. In all microcosms, a single type of Methylobacter represented the major methane-oxidizing partner. The accompanying members of the communities revealed different trajectories in response to different oxygen tensions, with Methylotenera species being the early responders to methane stimulus under both conditions. The communities in both conditions were convergent in terms of their assemblage, suggesting selection for specific taxa. Our results support prior observations from metagenomics on distribution of carbon from methane among diverse bacterial populations and further suggest that communities are likely responsible for methane cycling, rather than a single type of microbe. PMID:25333464

  10. [Microcosm Simulation Study and Methylmercury Forming Mechanism at Landscape Water of City].

    PubMed

    Liu, Xiao-hong; Si, You-bin; Guo, Zi-wei; Du, Cheng-zhu; Zhu, Cong-cong

    2016-04-15

    Mercury is harmful to the environment, which has gradually become one of the research hotspots. Sediments, as a main repository of pollutants, have an important impact on water quality and the internal organisms, which deserves our research. In this paper, we focused on Hefei landscape water sediment and tried to investigate the status of inorganic mercury and methylmercury pollutions in the sediment. To study the conversion process from inorganic mercury to methylmercury and their enrichment levels and mechanism, we established the ecological chain of "sediment-water-grass-fish" through analog microcosm examination. The results were as follows: from ten water and sediment samples in Hefei landscape water sediment, we found that the contents of inorganic mercury and methylmercury ranged 11.74-13.12 µg · kg⁻¹ and 0.37-2.23 µg · kg⁻¹, respectively. The microcosm examination showed that: with increasing culture time, inorganic mercury in sediments gradually decreased. There was a phenomenon that the content of methylmercury increased at first and then decreased to reach the balance later. Both the inorganic mercury and methylmercury in water change showed an increasing trend. The enrichment contents of inorganic mercury in Egeria densa Planch, and golden mandarin fish (Siniperca scherzeri Steindachner) were low while their enrichment of methylmercury could he great. In addition, we found that both the bioaccumulation ability and the enrichment coefficient of methylmercury in the body of golden mandarin fish were the maximum during the same period. PMID:27548953

  11. Antimicrobial Susceptibility and Composition of Microcosm Dental Plaques Supplemented with Sucrose

    PubMed Central

    Pratten, J.; Wilson, M.

    1999-01-01

    The aims of this study were to evaluate the effects of repeated chlorhexidine gluconate (CHG) pulsing on the viability and bacterial composition of microcosm dental plaques derived from human saliva. The biofilms were grown on bovine enamel discs in a constant-depth film fermentor fed with an artificial saliva which was supplemented thrice daily with sucrose. The microcosm plaques had total viable anaerobic counts of 5 × 108 CFU per mm2 and consisted of 12% Actinomyces spp., 85% streptococci, and 0.2% Veillonella spp. When pulsed twice daily with 0.2% CHG, there was an immediate 1.3-log10 reduction in the total viable (anaerobic) count. However, as pulsing continued, the viable counts recovered, and after 4 days, the anaerobic count reached its pre-CHG-pulsing level, although the bacterial composition of the biofilms had changed. The results of this study show that twice-daily pulsing with 0.2% CHG over a 4-day period was ineffective at reducing the total anaerobic viable count of the biofilms but did alter their bacterial composition. PMID:10390209

  12. Biotransformation at 10 C of di-n-butyl phthalate in subsurface microcosms

    SciTech Connect

    Chauret, C.; Inniss, W.E.; Mayfield, C.I.

    1996-09-01

    Di-n-butyl phthalate (DBP) was found to be transformed by microorganisms under aerobic and anaerobic conditions at 10 C in microcosms simulating the Canadian Forces Base (CFB) Borden subsurface environment. Biotransformation of DBP was observed under aerobic, nitrate-reducing, Fe(III)-reducing, and sulfate-reducing conditions. The biotransformation of DBP in the microcosms was significantly decrease3d as the redox potential was lowered, especially under sulfate-reducing conditions. However, other factors such as nutrient depletion and buildup of toxic intermediates could have affected the biotransformation rates. The highest DBP biotransformation rate (0.57 {micro}g DBP{center_dot}g sediment{sup {minus}1}{center_dot}day{sup {minus}1}) was under sulfate-reducing conditions. Biotransformation of DBP at 10 C was significantly enhanced by the addition of 10 mM NaNO{sub 3} suggesting that both the addition of nitrate and high redox conditions favor its biotransformation in subsurface environments.

  13. Effects of Mycorrhizal and Endophytic Fungi on Plant Community: a Microcosm Study

    PubMed Central

    Park, Sang-Hyun

    2007-01-01

    This study was conducted to investigate the effects of foliar endophytic fungi and arbuscular mycorrhizal fungi (AMF) on plant community structure in experimental microcosms containing an assemblage of five species of plants (Oenothera odorata, Plantago asiatica, Trifolium repens, Isodon japonicas and Aster yomena). Leaves of Sasa borealis, Potentilla fragarioides, and Viola mandshurica were collected in Chungbuk, Korea. Endophytic fungi were isolated from the surface sterilized leaves and identified to species level using molecular and morphological techniques. Four isolates of the endophytic fungi were inoculated to the leaves of host plants in the microcosms. Also, three species of AMF spores were extracted from pure cultures and the mixture of the three species inoculated to the roots of the plants. After four months of growth in a green house, effects of both symbiotic fungi on plant species diversity, community composition and productivity were examined. The plant species diversity showed significant differences with inoculation of the symbiotic fungi. Results indicate that AMF significantly affect plant productivity and plant community structure. PMID:24015095

  14. Effects of mycorrhizal and endophytic fungi on plant community: a microcosm study.

    PubMed

    Park, Sang-Hyun; Eom, Ahn-Heum

    2007-12-01

    This study was conducted to investigate the effects of foliar endophytic fungi and arbuscular mycorrhizal fungi (AMF) on plant community structure in experimental microcosms containing an assemblage of five species of plants (Oenothera odorata, Plantago asiatica, Trifolium repens, Isodon japonicas and Aster yomena). Leaves of Sasa borealis, Potentilla fragarioides, and Viola mandshurica were collected in Chungbuk, Korea. Endophytic fungi were isolated from the surface sterilized leaves and identified to species level using molecular and morphological techniques. Four isolates of the endophytic fungi were inoculated to the leaves of host plants in the microcosms. Also, three species of AMF spores were extracted from pure cultures and the mixture of the three species inoculated to the roots of the plants. After four months of growth in a green house, effects of both symbiotic fungi on plant species diversity, community composition and productivity were examined. The plant species diversity showed significant differences with inoculation of the symbiotic fungi. Results indicate that AMF significantly affect plant productivity and plant community structure. PMID:24015095

  15. Effect of application solvents on heterotrophic and nitrifying populations in soil microcosms

    SciTech Connect

    Miller, J.L.; Sardo, M.A.; Thompson, T.L.; Miller, R.M.

    1997-03-01

    Agricultural practices may cause contamination of soil and ground water with a combination of organic compounds (pesticides and fuel) and nitrogen fertilizers. In coupled microcosm studies that monitored the mineralization of naphthalene and the nitrification of ammonia, it was observed that the solvent (dichloromethane) used to apply naphthalene to the soil inhibited nitrification, although there was no effect on naphthalene mineralization. Further studies were performed with a series of application solvents: methanol, acetonitrile, trichloromethane, and dichloromethane. Soil and solvent were allowed to equilibrate with ambient air for various times before capping and incubation of microcosms. Results indicated that dichloromethane equilibrated for 5 mins inhibited nitrification for at least 3 weeks relative to the control (water). Acetonitrile and trichloromethane similarly inhibited nitrification. Methanol and dichloromethane equilibrated for 60 mins also significantly delayed nitrification, although to a lesser extent. Inhibition of nitrification was not permanent, and nitrification activity was eventually restored in all systems tested. None of the solvents inhibited mineralization of the added carbon source. These results indicate that special care must be taken to ensure that applications solvents do not affect the activity of sensitive microbial populations, such as the nitrifiers, that may be part of a study.

  16. Differential Decay of Wastewater Bacteria and Change of Microbial Communities in Beach Sand and Seawater Microcosms.

    PubMed

    Zhang, Qian; He, Xia; Yan, Tao

    2015-07-21

    Laboratory microcosm experiments were conducted to determine the decay kinetics of wastewater bacteria and the change of microbial communities in beach sand and seawater. Cultivation-based methods showed that common fecal indicator bacteria (FIBs; Escherichia coli, enterococci, and Clostridium perfringens) exhibited biphasic decay patterns in all microcosms. Enterococci and C. perfringens, but not E. coli, showed significantly smaller decay rates in beach sand than in seawater. Cultivation-independent qPCR quantification of 16S rRNA gene also showed significantly slower decrease of total bacterial densities in beach sand than in seawater. Microbial community analysis by next-generation sequencing (NGS) further illustrated that the decreasing relative abundance of wastewater bacteria was contrasted by the increase in indigenous beach sand and seawater microbiota, and the overall microbial community dynamics corresponded well with the decay of individual FIB populations. In summary, the differential decay of wastewater bacteria in beach sand and in seawater provides a kinetic explanation to the often-observed higher abundance of FIBs in beach sand, and the NGS-based microbial community analysis can provide valuable insights to understanding the fate of wastewater bacteria in the context of indigenous microbial communities in natural environments. PMID:26125493

  17. Methane-fed microbial microcosms show differential community dynamics and pinpoint taxa involved in communal response.

    PubMed

    Oshkin, Igor Y; Beck, David A C; Lamb, Andrew E; Tchesnokova, Veronika; Benuska, Gabrielle; McTaggart, Tami L; Kalyuzhnaya, Marina G; Dedysh, Svetlana N; Lidstrom, Mary E; Chistoserdova, Ludmila

    2015-05-01

    We report observations on the dynamics of bacterial communities in response to methane stimulus in laboratory microcosm incubations prepared with lake sediment samples. We first measured taxonomic compositions of long-term enrichment cultures and determined that, although dominated by Methylococcaceae types, these cultures also contained accompanying types belonging to a limited number of bacterial taxa, methylotrophs and non-methylotrophs. We then followed the short-term community dynamics, in two oxygen tension regimens (150 μM and 15 μM), observing rapid loss of species diversity. In all microcosms, a single type of Methylobacter represented the major methane-oxidizing partner. The accompanying members of the communities revealed different trajectories in response to different oxygen tensions, with Methylotenera species being the early responders to methane stimulus under both conditions. The communities in both conditions were convergent in terms of their assemblage, suggesting selection for specific taxa. Our results support prior observations from metagenomics on distribution of carbon from methane among diverse bacterial populations and further suggest that communities are likely responsible for methane cycling, rather than a single type of microbe. PMID:25333464

  18. Evaluation of PCB dechlorination pathways in anaerobic sediment microcosms using an anaerobic dechlorination model.

    PubMed

    Demirtepe, Hale; Kjellerup, Birthe; Sowers, Kevin R; Imamoglu, Ipek

    2015-10-15

    A detailed quantitative analysis of anaerobic dechlorination (AD) pathways of polychlorinated biphenyls (PCBs) in sediment microcosms was performed by applying an anaerobic dechlorination model (ADM). The purpose of ADM is to systematically analyze changes in a contaminant profile that result from microbial reductive dechlorination according to empirically determined dechlorination pathways. In contrast to prior studies that utilized modeling tools to predict dechlorination pathways, ADM also provides quantification of individual pathways. As only microbial reductive dechlorination of PCBs occurred in the modeled laboratory microcosms, extensive analysis of AD pathways was possible without the complicating effect of concurrent physico-chemical or other weathering mechanisms. The results from this study showed: (1) ninety three AD pathways are active; (2) tetra- to hepta-chlorobiphenyl (CB) congeners were common intermediates in several AD pathways, penta-CBs being the most frequently observed; (3) the highest rates of dechlorination were for penta-CB homologs during the initial 185 days; (4) the dominant terminal products of AD were PCB 32(26-4), 49(24-25), 51(24-26), 52(25-25), 72(25-35), 73(26-35) and 100(246-24), (5) potential toxicity of the sediment was reduced. ADM serves as a powerful tool not only for a thorough analysis of AD pathways, but also for providing necessary input for numerical fate models (as a degradation term) that investigate dechlorination products or outcome of natural attenuation, or bioremediation/bioaugmentation of PCB-impacted sediments. PMID:25913678

  19. Interactions among buffelgrass, phenanthrene and phenanthrene-degrading bacteria in gnotobiotic microcosms.

    PubMed

    Robert, Francoise M; Sun, Wenhao H; Toma, Marisa; Jones, Ryan K; Tang, Chung-Shih

    2008-07-15

    An experiment was undertaken in gnotobiotic microcosms to determine the role of buffelgrass (Cenchrus ciliaris) and a phenanthrene-degrading bacterium (strain PM600) in the degradation of phenanthrene. The Gram-negative bacterium was identified as a Sphingomonas sp. by 16S rRNA gene sequence analysis and as S. paucimobilis by biochemical tests (API 20 NE strips). Its yellow pigment corresponded to nostoxanthin and its cellular fatty acids were typical of the genus Sphingomonas. Moreover, it was devoid of lipopolysaccharides. Strain PM600 was tested for growth on mineral medium supplemented with No. 2 diesel, hexadecane, mineral oil, pristane, phenanthrene, and pyrene as single carbon sources. It was capable of utilizing phenanthrene only. In the gnotobiotic microcosms silica sand was either or not supplemented with 150 mg of phenanthrene kg(-1) sand, inoculated with strain PM600, and planted to sterile young seedlings of buffelgrass. After 28 days, 67% of the reduction of the phenanthrene concentration was assigned to degradation by the bacterium and ca. 20% to abiotic factors. No statistically significant effect of the young buffelgrass was found. In the absence of phenanthrene, the bacterial population significantly increased in the rhizosphere of buffelgrass. However, in the presence of buffelgrass and phenanthrene, the bacterial population preferentially responded to phenanthrene. The growth of buffelgrass was severely curtailed by phenanthrene in the absence of the bacterium. However, strain PM600 effectively protected buffelgrass against the phytotoxicity of phenanthrene. PMID:18569317

  20. Enhanced Horizontal Transfer of Antibiotic Resistance Genes in Freshwater Microcosms Induced by an Ionic Liquid

    PubMed Central

    Wang, Qing; Mao, Daqing; Mu, Quanhua; Luo, Yi

    2015-01-01

    The spread and propagation of antibiotic resistance genes (ARGs) is a worldwide public health concern. Ionic liquids (ILs), considered as “environmentally friendly” replacements for industrial organic solvents, have been widely applied in modern industry. However, few data have been collected regarding the potential ecological and environmental risks of ILs, which are important for preparing for their potential discharge into the environment. In this paper, the IL 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]) (0.001-5.0 g/L) was tested for its effects on facilitating ARGs horizontal transfer mediated by plasmid RP4 in freshwater microcosms. In the horizontal transfer microcosms, the transfer frequency of plasmid RP4 was significantly enhanced (60-fold higher than untreated groups) by the IL [BMIm][PF6] (1.0 g/L). Meanwhile, two strains of opportunistic pathogen Acinetobacter spp. and Salmonella spp. were isolated among the transconjugants, illustrating plasmid RP4 mediated horizontal transfer of ARGs occurred in pathogen. This could increase the risk of ARGs dissemination to human pathogens and pose great threat to public health. The cause that [BMIm[PF6] enhanced the transfer frequency of plasmid RP4 was proposed by suppressed cell membrane barrier and enhanced cell membrane permeability, which was evidenced by flow cytometry (FCM). This is the first report that some ILs facilitate horizontal transfer of plasmid RP4 which is widely distributed in the environment and thus add the adverse effects of the environmental risk of ILs. PMID:25951456

  1. Survival behaviour and virulence of the fish pathogen Vibrio ordalii in seawater microcosms.

    PubMed

    Ruiz, Pamela; Poblete-Morales, Matías; Irgang, Rute; Toranzo, Alicia E; Avendaño-Herrera, Ruben

    2016-06-15

    Vibrio ordalii, the causative agent of atypical vibriosis, is a Gram-negative, motile, rod-shaped bacterium that severely affects the salmonid aquaculture industry. V. ordalii has been biochemically, antigenically and genetically characterized. However, studies on the survival behaviour of this bacterium in aquatic environments are scarce, and there is no information regarding its disease transmission and infectious abilities outside of the fish host or regarding water as a possible reservoir. The present study investigated the survival behaviour of V. ordalii Vo-LM-06 and Vo-LM-18 in sterile and non-sterile seawater microcosms. After a year in sterile seawater without nutrients, 1% of both V. ordalii strains survived (~10(3) colony-forming units ml(-1)), and long-term maintenance did not affect bacterial biochemical or genetic properties. Additionally, V. ordalii maintained for 60 d in sterile seawater remained infective in rainbow trout Oncorhynchus mykiss. However, after 2 d of natural seawater exposure, this bacterium became non-culturable, indicating that autochthonous microbiota may play an important role in survival. Recuperation assays that added fresh medium to non-sterile microcosms did not favour V. ordalii recovery on solid media. Our results contribute towards a better understanding of V. ordalii survival behaviour in seawater ecosystems. PMID:27304868

  2. 50 CFR 622.276 - Landing fish intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Dolphin and Wahoo Fishery Off the Atlantic States § 622.276 Landing fish intact. (a) Dolphin and wahoo in or...

  3. 50 CFR 622.276 - Landing fish intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Dolphin and Wahoo Fishery Off the Atlantic States § 622.276 Landing fish intact. (a) Dolphin and wahoo in or...

  4. IntAct: an open source molecular interaction database

    PubMed Central

    Hermjakob, Henning; Montecchi-Palazzi, Luisa; Lewington, Chris; Mudali, Sugath; Kerrien, Samuel; Orchard, Sandra; Vingron, Martin; Roechert, Bernd; Roepstorff, Peter; Valencia, Alfonso; Margalit, Hanah; Armstrong, John; Bairoch, Amos; Cesareni, Gianni; Sherman, David; Apweiler, Rolf

    2004-01-01

    IntAct provides an open source database and toolkit for the storage, presentation and analysis of protein interactions. The web interface provides both textual and graphical representations of protein interactions, and allows exploring interaction networks in the context of the GO annotations of the interacting proteins. A web service allows direct computational access to retrieve interaction networks in XML format. IntAct currently contains ∼2200 binary and complex interactions imported from the literature and curated in collaboration with the Swiss-Prot team, making intensive use of controlled vocabularies to ensure data consistency. All IntAct software, data and controlled vocabularies are available at http://www.ebi.ac.uk/intact. PMID:14681455

  5. IntAct: an open source molecular interaction database.

    PubMed

    Hermjakob, Henning; Montecchi-Palazzi, Luisa; Lewington, Chris; Mudali, Sugath; Kerrien, Samuel; Orchard, Sandra; Vingron, Martin; Roechert, Bernd; Roepstorff, Peter; Valencia, Alfonso; Margalit, Hanah; Armstrong, John; Bairoch, Amos; Cesareni, Gianni; Sherman, David; Apweiler, Rolf

    2004-01-01

    IntAct provides an open source database and toolkit for the storage, presentation and analysis of protein interactions. The web interface provides both textual and graphical representations of protein interactions, and allows exploring interaction networks in the context of the GO annotations of the interacting proteins. A web service allows direct computational access to retrieve interaction networks in XML format. IntAct currently contains approximately 2200 binary and complex interactions imported from the literature and curated in collaboration with the Swiss-Prot team, making intensive use of controlled vocabularies to ensure data consistency. All IntAct software, data and controlled vocabularies are available at http://www.ebi.ac.uk/intact. PMID:14681455

  6. 56. POWDER MAGAZINE, VIEW OF INTACT WOOD SHEATHING ON THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. POWDER MAGAZINE, VIEW OF INTACT WOOD SHEATHING ON THE SOUTHWEST REAR VENTILATION PASSAGE. (SHEATHING HELP CONTROL HUMIDITY AND DECREASE DANGER OF MAETAL STRIKING STONE AND SPARKING.) - Fort Monroe, Fortress, Hampton, Hampton, VA

  7. Introduction of mercury resistant bacterial strains to Hg(II) amended soil microcosms increases the resilience of the natural microbial community to mercury stress

    SciTech Connect

    de Lipthay, Julia R.; Rasmussen, Lasse D.; Serensen, Soren J.

    2004-03-17

    Heavy metals are among the most important groups of pollutant compounds, and they are highly persistent in the soil environment. Techniques that can be used for the remediation of heavy metal contaminated environments thus need to be evolved. In the present study we evaluated the effect of introducing a Hg resistance plasmid in subsurface soil communities. This was done in microcosms with DOE subsurface soils amended with 5-10 ppm of HgCl2. Two microcosms were set up. In microcosm A we studied the effect of adding strain S03539 containing either the Hg resistance conjugative plasmid, pJORD 70, or the Hg resistance mobilizable plasmid, pPB117. In microcosm B we studied the effect of adding strain KT2442 with and without pJORD70. For both microcosms, the effect on the resilience of the indigenous bacterial community as well as the effect on the soil concentration of Hg was evaluated.

  8. Vesta is not an intact protoplanet

    NASA Astrophysics Data System (ADS)

    Consolmagno, G.; Turrini, D.; Golabek, G.; Svetsov, V.; Sirono, S.; Tsiganis, K.

    2014-07-01

    The Dawn mission was designed to explore ''remnant intact protoplanets from the earliest epoch of solar system formation'' [1]. However, models of Vesta composed of an iron core, olivine mantle, and HED crust in chondritic proportions cannot match the joint constraints from Dawn [1] of Vesta's density, core size, and the extremely limited presence of exposed olivine on its surface. Vesta has a mean density of 3456 kg/m3 and its surface composition is well matched by howardites. The Dawn gravity data suggest a nickel-iron core of radius 110 km and density 7500--7800 kg/m3. The Rheasilvia impact basin, formed within a pre-existing large basin, Veneneia, should have excavated material from a depth of 50 km to 80 km or more below Vesta's surface [2]. If the howardite crust were thinner than 50--80 km, a significant amount of olivine-rich material, derived from depth, would have been exposed within this basin; models suggest that olivine would also be distributed both on Vesta's surface and in space as meteorite-source Vestoids. Such olivine is rare on Vesta, among the Vestoids, or in our meteorite collection. Vesta's density is similar to an L chondrite, but the Na and K abundances in Vesta are strongly depleted compared to chondrites and the average metal content of an L chondrite, 8.4% by mass, would give a core radius less than 90 km. A 110 km radius metallic core, via the Dawn data, represents 15% of Vesta's mass. The Mg/Al ratio in cosmic abundances is about 10:1, but roughly 1:1 within the eucrites; thus if Vesta started with cosmic abundances, the eucrites can only represent 10% of the parent body total mass. Likewise the 10 x chondritic rare earth trace elements (REE) abundance seen in most eucrites demands that, regardless of formation mechanism, these basalts were crystallized from a melt representing 10% of the mass of the source region [3]. Thus the howardite crust of a chondritic HED parent body, mixing all the available eucritic and diogenitic material

  9. Evaluation of graphite for environmental toxicity using the standard aquatic microcosm. Technical report, June 1986-March 1987

    SciTech Connect

    Landis, W.G.; Chester, N.A.; Haley, M.V.; Johnson, D.W.; Tauber, R.M.

    1988-08-01

    The impact of a graphite dust on an aquatic ecosystem model, the Standard Aquatic microcosm (SAM), was investigated. Graphite dust produced effects that resembled eutrophication in that a diversity decreased, ammonia increased, and a photosynthesis/respiration ratio of less than one was observed in the highest concentration. Compared to brass dust, graphite has much less potential to adversely impact aquatic ecosystems.

  10. COMPARISON OF MICROBIAL TRANSFORMATION RATE COEFFICIENTS OF XENOBIOTIC CHEMICALS BETWEEN FIELD-COLLECTED AND LABORATORY MICROCOSM MICROBIOTA

    EPA Science Inventory

    Two second-order transformation rate coefficients--kb, based on total plate counts, and kA, based on periphyton-colonized surface areas--were used to compare xenobiotic chemical transformation by laboratory-developed (microcosm) and by field-collected microbiota. Similarity of tr...

  11. ENRICHMENT OF CADMIUM-MEDIATED ANTIBIOTIC-RESISTANT BACTERIA IN A DOUGLAS-FIR 'PSEUDOTSUGA MENZIESII' LITTER MICROCOSM

    EPA Science Inventory

    A set of Douglas-fir needle microcosms was amended with cadmium, acid, a combination of both, or neither. After 2 weeks of incubation, bacterial colony counts were made of litter homogenates inoculated onto agar media containing an antibiotic (streptomycin, chloromycetin, ampicil...

  12. Hydrocarbon biodegradation by Arctic sea-ice and sub-ice microbial communities during microcosm experiments, Northwest Passage (Nunavut, Canada).

    PubMed

    Garneau, Marie-Ève; Michel, Christine; Meisterhans, Guillaume; Fortin, Nathalie; King, Thomas L; Greer, Charles W; Lee, Kenneth

    2016-10-01

    The increasing accessibility to navigation and offshore oil exploration brings risks of hydrocarbon releases in Arctic waters. Bioremediation of hydrocarbons is a promising mitigation strategy but challenges remain, particularly due to low microbial metabolic rates in cold, ice-covered seas. Hydrocarbon degradation potential of ice-associated microbes collected from the Northwest Passage was investigated. Microcosm incubations were run for 15 days at -1.7°C with and without oil to determine the effects of hydrocarbon exposure on microbial abundance, diversity and activity, and to estimate component-specific hydrocarbon loss. Diversity was assessed with automated ribosomal intergenic spacer analysis and Ion Torrent 16S rRNA gene sequencing. Bacterial activity was measured by (3)H-leucine uptake rates. After incubation, sub-ice and sea-ice communities degraded 94% and 48% of the initial hydrocarbons, respectively. Hydrocarbon exposure changed the composition of sea-ice and sub-ice communities; in sea-ice microcosms, Bacteroidetes (mainly Polaribacter) dominated whereas in sub-ice microcosms, the contribution of Epsilonproteobacteria increased, and that of Alphaproteobacteria and Bacteroidetes decreased. Sequencing data revealed a decline in diversity and increases in Colwellia and Moritella in oil-treated microcosms. Low concentration of dissolved organic matter (DOM) in sub-ice seawater may explain higher hydrocarbon degradation when compared to sea ice, where DOM was abundant and composed of labile exopolysaccharides. PMID:27387912

  13. Use Of Statistical Tools To Evaluate The Reductive Dechlorination Of High Levels Of TCE In Microcosm Studies

    EPA Science Inventory

    A large, multi-laboratory microcosm study was performed to select amendments for supporting reductive dechlorination of high levels of trichloroethylene (TCE) found at an industrial site in the United Kingdom (UK) containing dense non-aqueous phase liquid (DNAPL) TCE. The study ...

  14. EVALUATION OF TERRESTRIAL MICROCOSMS FOR DETECTION, FATE, AND SURVIVAL ANALYSIS OF GENETICALLY ENGINEERED MICROORGANISMS AND THEIR RECOMBINANT GENETIC MATERIAL

    EPA Science Inventory

    Terrestrial microcosms have been used for several decades by researcher to evaluate the fate and transport of xenobiotics in the environment; however, very little information is available on their application to the fate, survival, and transport of recombinant bacteria and microb...

  15. Application of microcosmic system for assessment of insecticide effects on biomarker responses in ecologically different earthworm species.

    PubMed

    Velki, Mirna; Hackenberger, Branimir K; Lončarić, Zeljka; Hackenberger, Davorka K

    2014-06-01

    Earthworms from different ecological categories--epigeic Eisenia andrei and Lumbricus rubellus, endogeic Octolasion lacteum and anecic Lumbricus terrestris--were exposed in a microcosmic system to three commonly used insecticides. The effects of the insecticides were evaluated by measuring the following molecular biomarkers-the activities of AChE, CES, CAT, GST and the concentration of GSH. The results showed that environmentally relevant doses of organophosphates dimethoate and pirimiphos-methyl significantly affected the measured biomarkers, whereas pyrethroid deltamethrin did not affect the earthworms at the recommended agricultural dose. Considering the ecological category of earthworms, the results were inhomogeneous and species-specific differences in the biomarker responses were recorded. Since the biomarker responses of the investigated earthworm species were different after exposure to organophosphates in a microcosm compared to the exposure via standardized toxicity tests, two types of species sensitivity should be distinguished-physiological and environmental sensitivity. In addition, the hormetic effect of organophosphates on AChE and CES activities was recorded. The detection of hormesis in a microcosm is of great importance for future environmental research and soil biomonitoring, since in a realistic environment pollutants usually occur at low concentrations that could cause a hormetic effect. The results demonstrate the importance of the application of microcosmic systems in the assessment of the effects of environmental pollutants and the necessity of taking into account the possible differences between physiological and environmental species sensitivity. PMID:24650551

  16. Unusual isotopic composition of C-CO2 from sterilized soil microcosms: a new way to separate intracellular from extracellular respiratory metabolisms.

    NASA Astrophysics Data System (ADS)

    Kéraval, Benoit; Alvarez, Gaël; Lehours, Anne Catherine; Amblard, Christian; Fontaine, Sebastien

    2015-04-01

    The mineralization of organic C requires two main steps. First, microorganisms secrete exoenzymes in soil in order to depolymerize plant and microbial cell walls and release soluble substrates for microbial assimilation. The second step of mineralization, during which C is released as CO2, implies the absorption and utilization of solubilized substrates by microbial cells with the aim to produce energy (ATP). In cells, soluble substrates are carried out by a cascade of respiratory enzymes, along which protons and electrons are transferred from a substrate to oxygen. Given the complexity of this oxidative metabolism and the typical fragility of respiratory enzymes, it is traditionally considered that respiration (second step of C mineralization process) is strictly an intracellular metabolism process. The recurrent observations of substantial CO2 emissions in soil microcosms where microbial cells have been reduced to extremely low levels challenges this paradigm. In a recent study where some respiratory enzymes have shown to function in an extracellular context in soils, Maire et al. (2013) suggested that an extracellular oxidative metabolism (EXOMET) substantially contributes to CO2 emission from soils. This idea is supported by the recent publication of Blankinship et al., 2014 who showed the presence of active enzymes involved in the Krebs cycle on soil particles. Many controversies subsist in the scientific community due to the presence of non-proliferating but morphologically intact cells after irradiation that could substantially contribute to those soil CO2 emissions. To test whether a purely extracellular oxidative metabolism contribute to soil CO2 emissions, we combined high doses of gamma irradiations to different time of soil autoclaving. The presence of active and non-active cells in soil was checked by DNA and RNA extraction and by electronic microscopy. None active cells (RNA-containing cells) were detectable after irradiation, but some morphological

  17. Vulnerability of ecosystems to climate change moderated by habitat intactness.

    PubMed

    Eigenbrod, Felix; Gonzalez, Patrick; Dash, Jadunandan; Steyl, Ilse

    2015-01-01

    The combined effects of climate change and habitat loss represent a major threat to species and ecosystems around the world. Here, we analyse the vulnerability of ecosystems to climate change based on current levels of habitat intactness and vulnerability to biome shifts, using multiple measures of habitat intactness at two spatial scales. We show that the global extent of refugia depends highly on the definition of habitat intactness and spatial scale of the analysis of intactness. Globally, 28% of terrestrial vegetated area can be considered refugia if all natural vegetated land cover is considered. This, however, drops to 17% if only areas that are at least 50% wilderness at a scale of 48×48 km are considered and to 10% if only areas that are at least 50% wilderness at a scale of 4.8×4.8 km are considered. Our results suggest that, in regions where relatively large, intact wilderness areas remain (e.g. Africa, Australia, boreal regions, South America), conservation of the remaining large-scale refugia is the priority. In human-dominated landscapes, (e.g. most of Europe, much of North America and Southeast Asia), focusing on finer scale refugia is a priority because large-scale wilderness refugia simply no longer exist. Action to conserve such refugia is particularly urgent since only 1 to 2% of global terrestrial vegetated area is classified as refugia and at least 50% covered by the global protected area network. PMID:25059822

  18. Structural and molecular interrogation of intact biological systems.

    PubMed

    Chung, Kwanghun; Wallace, Jenelle; Kim, Sung-Yon; Kalyanasundaram, Sandhiya; Andalman, Aaron S; Davidson, Thomas J; Mirzabekov, Julie J; Zalocusky, Kelly A; Mattis, Joanna; Denisin, Aleksandra K; Pak, Sally; Bernstein, Hannah; Ramakrishnan, Charu; Grosenick, Logan; Gradinaru, Viviana; Deisseroth, Karl

    2013-05-16

    Obtaining high-resolution information from a complex system, while maintaining the global perspective needed to understand system function, represents a key challenge in biology. Here we address this challenge with a method (termed CLARITY) for the transformation of intact tissue into a nanoporous hydrogel-hybridized form (crosslinked to a three-dimensional network of hydrophilic polymers) that is fully assembled but optically transparent and macromolecule-permeable. Using mouse brains, we show intact-tissue imaging of long-range projections, local circuit wiring, cellular relationships, subcellular structures, protein complexes, nucleic acids and neurotransmitters. CLARITY also enables intact-tissue in situ hybridization, immunohistochemistry with multiple rounds of staining and de-staining in non-sectioned tissue, and antibody labelling throughout the intact adult mouse brain. Finally, we show that CLARITY enables fine structural analysis of clinical samples, including non-sectioned human tissue from a neuropsychiatric-disease setting, establishing a path for the transmutation of human tissue into a stable, intact and accessible form suitable for probing structural and molecular underpinnings of physiological function and disease. PMID:23575631

  19. Experimental modeling of the processes resulting from the introduction of the transgenic microorganism Escherichia coli Z905/pPHL7 (lux+) into aquatic microcosms

    NASA Astrophysics Data System (ADS)

    Kargatova, T.; Popova, L.; Pechurkin, N.

    The processes resulting from the introduction of the transgenic microorganism (TM) E. coli Z905/pPHL7 into aquatic microcosms have been modeled experimentally. It has been shown that the TM E. coli is able to adapt to a long co-existence with aboriginal heterotrophic microflora, whatever the structure of a microcosm. In more complex microcosms the numerical dynamics of the introduced E. coli Z905/pPHL7 population is more stable. In the TM populations staying in the microcosms for a prolonged time changes are recorded in the phenotypic expression of plasmid genes (ampicillin resistance and the luminescence level) and chromosome genes (morphological and physiological traits). However, in every study microcosm the recombinant plasmid persists in the TM cells during 6 years after the introduction, and as the population adapts to the conditions of the microcosms, the efficiency of the cloned gene expression in the cells is restored. In the microcosms with high microalgal counts (107 cells/ml), cells with a high threshold of sensitivity to ampicillin dominate in the population of the TM E. coli Z905/pPHL7.

  20. Experimental evaluation of the processes resulting from the introduction of the transgenic microorganism Escherichia coli Z905/pPHL7 ( lux+) into aquatic microcosms

    NASA Astrophysics Data System (ADS)

    Kargatova, T. V.; Boyandin, A. N.; Popova, L. Yu.; Pechurkin, N. S.

    The processes resulting from the introduction of the tranagenic microorganism (TM) E. coli Z905/pPHL7 into aquatic microcosms have been modeled experimentally. It has been shown that the TM E. coli is able to adapt to a long co-existence with indigenous heterotropbic microflora in variously structured microcosms. In more complex microcosms the numerical dynamics of the introduced E. coli Z905/pPHL7 population is more stable. In the TM populations staying in the microcosms for a prolonged time, changes are recorded in the phenotypic expression of plasmid genes (ampicillin resistance and the luminescence level) and chromosome genes (morphological and physiological traits). However, in our study microcosms, the recombinant plasmid persisted in the TM cells for 6 years after the introduction, and as the population adapts to the conditions of the microcosms, the efficiency of the cloned gene expression in the cells is restored. In the microcosms with high microalgal counts (10 7 cells/ml), cells with a high threshold of sensitivity to ampicillin dominate in the population of the TM E. coli Z905/pPHL7.

  1. A microcosm investigation of fe (iron) removal using macrophytes of ramsar lake: A phytoremediation approach.

    PubMed

    Singh, Mayanglambam Muni; Rai, Prabhat Kumar

    2016-12-01

    The present study deals with the microcosm study of Fe (Iron) phytoremediation using Eichhornia crassipes, Lemna minor, Pistia stratiotes and Salvinia cucullata species collected from the Loktak Lake, a Ramsar Site which exists in north-eastern India (an Indo-Burma hotspot region). Efficiency of these four macrophytes was compared using different Fe concentrations of 1 mg L(-1), 3 mg L(-1) and 5 mg L(-1) for 4 days, 8 days and 12 days, respectively. E. crassipes was the most efficient macrophyte whereas L. minor was the least efficient. E. crassipes removed the highest percentage of Fe, i.e. 89% from 1 mg L(-1), 81.3% from 3 mg L(-1) and 73.2% from 5 mg L(-1) in 12-day experiment. PMID:27258126

  2. Solder wetting behavior enhancement via laser-textured surface microcosmic topography

    NASA Astrophysics Data System (ADS)

    Chen, Haiyan; Peng, Jianke; Fu, Li; Wang, Xincheng; Xie, Yan

    2016-04-01

    In order to reduce or even replace the use of Sn-Pb solder in electronics industry, the laser-textured surface microstructures were used to enhance the wetting behavior of lead free solder during soldering. According to wetting theory and Sn-Ag-Cu lead free solder performance, we calculated and designed four microcosmic structures with the similar shape and different sizes to control the wetting behavior of lead free solder. The micro-structured surfaces with different dimensions were processed on copper plates by fiber femtosecond laser, and the effect of microstructures on wetting behavior was verified experimentally. The results showed that the wetting angle of Sn-Ag-Cu solder on the copper plate with microstructures decreased effectively compared with that on the smooth copper plate. The wetting angles had a sound fit with the theoretical values calculated by wetting model. The novel method provided a feasible route for adjusting the wetting behavior of solders and optimizing solders system.

  3. Expression and transfer of engineered catabolic pathways harbored by Pseudomonas spp. introuduced into activated sludge microcosms

    SciTech Connect

    Nublein, K.; Maris, D.; Timmis, K.; Dwyer, D.F. )

    1992-10-01

    Two genetically engineered microorganisms (GEMs), Pseudomonas sp. strain B13 FR1(pFRC20P) (FR120) and Pseudomonas putida KT2440(pWWO-EB62) (EB62), were introduced into activated sludge microcosms that had the level of aeration, nutrient makeup, and microbial community structure of activated sludge reactors. FR120 contains an experimentally assembled ortho cleavage route for simultaneous degradation of 3-chlorobenzoate (3CB) and 4-methyl benzoate (4MB); EB62 contains a derivative TOL plasmid-encoded degradative pathway for toluene experimentally evolved so that it additionally processes 4-ethyl benzoate (4EB). Experiments assessed survival of the GEMs, their ability to degrade target substrates, and lateral transfer of plasmid-encoded recombinant DNA.

  4. Application of electrical methods to measure microbial activity in soils: Preliminary microcosm results

    SciTech Connect

    Cox, B.L. Sweet, A.; Majer, E.

    1997-12-01

    The application of the geophysical technique known as self-potential to the measurement of microbial activity was tested on laboratory microcosms containing ferric iron and iron-reducing bacteria Shewanella alga BrY. Measurements of the electrical response of silver-coated copper electrodes distributed along a Teflon probe inserted into sterile and inoculated layers containing either ferric chloride, ferric citrate, or ferric oxide rich soil were recorded over hours or days. Strong electrical signals reached values more negative than {minus}400 mV for all types of inoculated ferric iron layers. Electric signals in sterile control layers, by contrast, rarely reached values more negative than {minus}150 mV. These preliminary experiments indicate that it may be possible to apply the self-potential geophysical method to monitor bioremediation in the field.

  5. Survival and impact of genetically engineered Pseudomonas putida harboring mercury resistance gene in soil microcosms.

    PubMed

    Iwasaki, K; Uchiyama, H; Yagi, O

    1994-01-01

    The survival of genetically engineered and wild-type Pseudomonas putida PpY101, that contained a recombinant plasmid pSR134 conferring mercury resistance, were monitored in andosol and sand microcosms. The survival of genetically engineered and wild-type P. putida was not significantly different in andosol. The population change of the two strains was dissimilar in andosol and sand. The survival of genetically engineered and wild-type P. putida strains was affected by the water content of andosol, and increased with the increment of the water content. The impact of the addition of genetically engineered and wild-type P. putida strains on indigenous bacteria and fungi was examined. Inoculation of both strains had no apparent effect on the density of indigenous microorganisms. PMID:7764510

  6. Recolonisation of mine tailing by meiofauna in mesocosm and microcosm experiments.

    PubMed

    Gwyther, David; Batterham, Grant J; Waworuntu, Jorina; Gultom, Tonny H; Prayogo, Windy; Susetiono; Karnan

    2009-06-01

    The Batu Hijau copper/gold mine in Sumbawa, Indonesia processes ore at approximately 130,000tpd and discharges tailing via a submarine pipeline to depths below 3000m at the base of a submarine canyon. The study investigated recolonisation of tailing by meiofauna and its dependence on subsequent accumulation of natural sediment. Microcosm and mesocosm scale experiments were carried out using two tailing and two control samples, the latter comprising defaunated and unaffected natural sediment. All test materials were similar in physical and chemical respects, except for the higher copper concentration in the tailing. The abundances of meiofauna colonising defaunated controls and both tailing samples increased from zero to levels statistically indistinguishable from natural unaffected controls after 97 and 203days. Colonisation was well established in tailing from freshly mined ore after 40days, and in oxidized tailing from stockpiled ore after 65days, and was not dependent on settled natural material. PMID:19268316

  7. Individual-based model of bluegill sunfish production in aquatic mesocosms/microcosms

    SciTech Connect

    Florian, J.D. Jr.; Dixon, K.R.; DeAngelis, D.L.; Shaw, J.L.

    1994-12-31

    The development of an individual-based model for ag-ill sunfish, Lepomis macrochirus (Rafinesque) is described. Fish are modeled as an assemblage of individuals. Foraging, bioenergetics, interactions with conspecifics, and reproduction are modeled separately for each fish using control data from aquatic mesocosm/microcosm studies. The individual behavior of each fish is described by decision rules which specify what particular actions the fish performs on a daily basis. A summary of the most important behavioral rules for the model and how physical and resource environments can be taken into account is presented. Development of this type of modeling is pursued for ultimate use in field situations to better understand the influences of natural environmental conditions versus toxicant exposures on populations of fish through time.

  8. Survival and Phospholipid Fatty Acid Profiles of Surface and Subsurface Bacteria in Natural Sediment Microcosms

    PubMed Central

    Kieft, T. L.; Wilch, E.; O'Connor, K.; Ringelberg, D. B.; White, D. C.

    1997-01-01

    Although starvation survival has been characterized for many bacteria, few subsurface bacteria have been tested, and few if any have been tested in natural subsurface porous media. We hypothesized that subsurface bacteria may be uniquely adapted for long-term survival in situ. We further hypothesized that subsurface conditions (sediment type and moisture content) would influence microbial survival. We compared starvation survival capabilities of surface and subsurface strains of Pseudomonas fluorescens and a novel Arthrobacter sp. in microcosms composed of natural sediments. Bacteria were incubated for up to 64 weeks under saturated and unsaturated conditions in sterilized microcosms containing either a silty sand paleosol (buried soil) or a sandy silt nonpaleosol sediment. Direct counts, plate counts, and cell sizes were measured. Membrane phospholipid fatty acid (PLFA) profiles were quantified to determine temporal patterns of PLFA stress signatures and differences in PLFAs among strains and treatments. The Arthrobacter strains survived better than the P. fluorescens strains; however, differences in survival between surface and subsurface strains of each genus were not significant. Bacteria survived better in the paleosol than in the nonpaleosol and survived better under saturated conditions than under unsaturated conditions. Cell volumes of all strains decreased; however, sediment type and moisture did not influence rates of miniaturization. Both P. fluorescens strains showed PLFA stress signatures typical for gram-negative bacteria: increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl to monoenoic precursor fatty acids. The Arthrobacter strains showed few changes in PLFAs. Environmental conditions strongly influenced PLFA profiles. PMID:16535578

  9. Evaluation of simulated acid precipitation effects on forest microcosms. Final report

    SciTech Connect

    Kelly, J.M.; Strickland, R.C.; Weatherford, F.P.; Noggle, J.C.

    1984-04-01

    Microcosms were treated for a 30-month period with simulated precipitation acidified to four pH levels (5.7, 4.5, 4.0, and 3.5) to evaluate the impact of acid precipitation on foliar leaching, plant nutrient content, soil leaching, soil nutrient content, and litter decomposition. Direct effects of acid precipitation on diameter growth, bud break, leaf senescence, chlorophyll content, stomatal size, stomatal density, photosynthesis, respiration, transpiration, and cuticle erosion were evaluated on tulip poplar, white oak, and Virginia pine seedlings growing as mixed stands in the microcosms. None of the plant physiological or morphological parameters evaluated responded in a statistically significant manner as a result of treatment. A significant treatment canopy interaction was observed in the form of a 60 percent increase in calcium input in throughfall in response to the pH 3.5 treatment. Foliar nutrient content did not change in response to treatment nor did field measurements of decomposer activity. Soil analysis indicated a significantly lower concentration of exchangeable calcium and magnesium in the top 3.5 cm of the mineral soil in association with the pH 3.5 treatment. Soil leachate concentrations exhibited significant increases at both the 25 and 50 cm depths. However, at the 100 cm depth no significant response in concentration or elemental loss from the system was observed. Laboratory respiration measurements indicated a small, but statistically significant reduction in decomposer activity in the lower litter (02) horizon. This reduction was masked in the field measurements of decomposer activity due to the relatively small contribution of the 02 to total soil respiration. 38 references, 12 figures, 18 tables.

  10. Natural transformation and availability of transforming DNA to Acinetobacter calcoaceticus in soil microcosms.

    PubMed Central

    Nielsen, K M; van Weerelt, M D; Berg, T N; Bones, A M; Hagler, A N; van Elsas, J D

    1997-01-01

    A small microcosm, based on optimized in vitro transformation conditions, was used to study the ecological factors affecting the transformation of Acinetobacter calcoaceticus BD413 in soil. The transforming DNA used was A. calcoaceticus homologous chromosomal DNA with an inserted gene cassette containing a kanamycin resistance gene, nptII. The effects of soil type (silt loam or loamy sand), bacterial cell density, time of residence of A. calcoaceticus or of DNA in soil before transformation, transformation period, and nutrient input were investigated. There were clear inhibitory effects of the soil matrix on transformation and DNA availability. A. calcoaceticus cells reached stationary phase and lost the ability to be transformed shortly after introduction into sterile soil. The use of an initially small number of A. calcoaceticus cells and nutrients, resulting in bacterial growth, enhanced transformation frequencies within a limited period. The availability of introduced DNA for transformation of A. calcoaceticus cells disappeared within a few hours in soil. Differences in transformation frequencies between soils were found; A. calcoaceticus cells were transformed at a higher rate and for a longer period in a silt loam than in a loamy sand. Physical separation of DNA and A. calcoaceticus cells had a negative effect on transformation. Transformation was also detected in nonsterile soil microcosms, albeit only in the presence of added nutrients and at a reduced frequency. These results suggest that chromosomal DNA released into soil rapidly becomes unavailable for transformation of A. calcoaceticus. In addition, strain BD413 quickly loses the ability to receive, stabilize, and/or express exogenous DNA after introduction into soil. PMID:9143126

  11. Survival and phospholipid fatty acid profiles of surface and subsurface bacteria in natural sediment microcosms

    SciTech Connect

    Kieft, T.L.; Wilch, E.; O`Connor, K.

    1997-04-01

    Although starvation survival has been characterized for many bacteria, few subsurface bacteria have been tested, and few if any have been tested in natural subsurface porous media. We hypothesized that subsurface bacteria may be uniquely adapted for long-term survival in situ. We further hypothesized that subsurface conditions (sediment type and moisture content) would influence microbial survival. We compared starvation survival capabilities of surface and subsurface strains of Pseudomonas fluorescens and a novel Arthrobacter sp. in microcosms composed of natural sediments. Bacteria were incubated for up to 64 weeks under saturated and unsaturated conditions in sterilized microcosms containing either a silty sand paleosol (buried soil) or a sandy silt nonpaleosol sediment. Direct counts, plate counts, and cell sizes were measured. Membrane phospholipid fatty acid (PLFA) profiles were quantified to determine temporal patterns of PLFA stress signatures and differences in PLFAs among strains and treatments. The Arthrobacter strains survived better than the P. fluorescens strains; however, differences in survival between surface and subsurface strains of each genus were not significant. Bacteria survived better in the paleosol than in the nonpaleosol and survived better under saturated conditions than under unsaturated conditions. Cell volumes of all strains decreased; however, sediment type and moisture did not influence rates of miniaturization. Both P.fluorescens strains showed PLFA stress signatures typical for gram-negative bacteria: increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl to monoenoic precursor fatty acids. The Arthrobacter strains showed few changes in PLFAs. Environmental conditions strongly influenced PLFA profiles. 40 refs., 7 figs.

  12. Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment.

    PubMed

    Tsiola, A; Pitta, P; Fodelianakis, S; Pete, R; Magiopoulos, I; Mara, P; Psarra, S; Tanaka, T; Mostajir, B

    2016-04-01

    The growth rates of planktonic microbes in the pelagic zone of the Eastern Mediterranean Sea are nutrient limited, but the type of limitation is still uncertain. During this study, we investigated the occurrence of N and P limitation among different groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely or simultaneously), and the PO4 turnover time, prokaryotic heterotrophic activity, primary production, and the abundance of the different microbial components were measured. Flow cytometric and molecular fingerprint analyses showed that different heterotrophic prokaryotic groups were limited by different nutrients; total heterotrophic prokaryotic growth was limited by P, but only when both N and P were added, changes in community structure and cell size were detected. Phytoplankton were N and P co-limited, with autotrophic pico-eukaryotes being the exception as they increased even when only P was added after a 2-day time lag. The populations of Synechococcus and Prochlorococcus were highly competitive with each other; Prochlorococcus abundance increased during the first 2 days of P addition but kept increasing only when both N and P were added, whereas Synechococcus exhibited higher pigment content and increased in abundance 3 days after simultaneous N and P additions. Dinoflagellates also showed opportunistic behavior at simultaneous N and P additions, in contrast to diatoms and coccolithophores, which diminished in all incubations. High DNA content viruses, selective grazing, and the exhaustion of N sources probably controlled the populations of diatoms and coccolithophores. PMID:26626911

  13. Soil microcosm for testing the effects of chemical pollutants on soil fauna communities and trophic structure

    SciTech Connect

    Parmelee, R.W. . Dept. of Entomology); Wentsel, R.S.; Phillips, C.T.; Checkai, R.T. ); Simini, M. )

    1993-08-01

    A microcosm technique is presented that uses community and trophic-level analysis of soil nematodes and microarthropods to determine the effects of chemicals on soil systems. Forest soil was treated with either copper, p-nitrophenol, or trinitrotoluene. Nematodes were sorted into bacterivore, fungivore, herbivore, and omnivore-predator trophic groups, and a hatchling category. Microarthropods were sorted to the acarine suborders Prostigmata, Mesostigmata, and Oribatida; the insectan order Collembola; and a miscellaneous group. Omnivore-predator nematodes and meso-stigmatid and oribatid mites were the groups most sensitive to copper and were significantly reduced at levels as low as 100 [mu]g g[sup [minus]1] copper. Total nematode and microarthropod numbers declined above 200 [mu]g g[sup [minus]1] copper. Trophic structure analysis suggested that high sensitivity of nematode predators to intermediate levels of copper reduced predation on herbivore nematodes and resulted in greater numbers of nematodes compared to controls. p-Nitrophenol was very toxic to the nematode community, and all trophic groups were significantly reduced above 20 [mu]g g[sup [minus]1]. However, there was no effect of p-nitrophenol on microarthropods. Trinitrotoluene had no significant negative effect on total abundance of either groups of soil fauna, but oribatids were significantly reduced at 200 [mu]g g[sup [minus]1]. The results demonstrated that soil nematodes and microarthropods were sensitive indicators of environmental contaminants and that trophic-structure and community analysis has the potential to detect more subtle indirect effects of chemicals on soil food-web structure. The authors conclude that microcosms with field communities of soil microfauna offer high resolution of the ecotoxicological effects of chemicals in complex soil systems.

  14. A soil microcosm to test the effects of pollutants on soil nematode and microarthropod communities

    SciTech Connect

    Parmelee, R.W.; Wentsel, R.S.; Checkai, R.T.; Phillips, C.T.; Bohlen, P.J.

    1995-12-31

    Previous studies have demonstrated that microcosms with field collected soil nematode and microarthropod communities are suitable model systems to detect effects of toxins on soil food web structure and function. The authors investigated the toxicity of copper, cadmium, malathion, and Aroclor 1254 to nematodes (total, bacterivores, fungivores, herbivores, omnivore-predators, hatchlings) and microarthropods (Prostigmata, Mesostigmata, Oribatida, Collembola, other arthropods). Nematodes were sensitive indicators of copper application, and total numbers were reduced at 100 {micro}g g{sup {minus}1}. Fungivore, bacterivore and omnivore-predators were the most susceptible trophic groups. Cadmium had no effects on either nematode or microarthropod communities. Microarthropods were more sensitive to malathion than nematodes, and total microarthropod abundance was lower than controls at 320 {micro}g g{sup {minus}1}. Prostigmatid mites and other arthropods were the most affected groups. Only the herbivore nematode trophic group was affected by malathion, and numbers did not decline until 1,280 {micro}g g{sup {minus}1}. Aroclor 1254 also had a greater negative impact on microarthropods than on nematodes. Total microarthropod abundance declined at 2,500 {micro}g g{sup {minus}1}, while there was no effect on nematodes. Prostigmatid and oribatid mites were the most susceptible groups to PCB application. Strong differential sensitivity between nematode and microarthropod communities indicates that both groups need to be examined to fully evaluate the impact of chemicals on soil systems. The authors conclude that microcosms with field-collected communities of soil microfauna offer high resolution of the ecotoxicological effects of chemicals in complex soil systems.

  15. Net methylation of mercury in estuarine sediment microcosms amended with dissolved, nanoparticulate, and microparticulate mercuric sulfides.

    PubMed

    Zhang, Tong; Kucharzyk, Katarzyna H; Kim, Bojeong; Deshusses, Marc A; Hsu-Kim, Heileen

    2014-08-19

    The production of methylmercury (MeHg) by anaerobic microorganisms depends in part on the speciation and bioavailability of inorganic mercury to these organisms. Our previous work with pure cultures of methylating bacteria has demonstrated that the methylation potential of mercury decreased during the aging of mercuric sulfides (from dissolved to nanoparticulate and microcrystalline HgS). The objective of this study was to understand the relationship between mercury sulfide speciation and methylation potential in experiments that more closely simulate the complexity of sediment settings. The study involved sediment slurry microcosms that represented a spectrum of salinities in an estuary and were each amended with different forms of mercuric sulfides: dissolved Hg and sulfide, nanoparticulate HgS (3-4 nm in diameter), and microparticulate HgS (>500 nm). The results indicated that net MeHg production was influenced by both the activity of sulfate-reducing microorganisms (roughly represented by the rate of sulfate loss) and the bioavailability of mercury. In the presence of abundant sulfate and carbon sources (supporting relatively high microbial activity), net MeHg production in the slurries amended with dissolved Hg was greater than in slurries amended with nano-HgS, similar to previous experiments with pure bacterial cultures. In microcosms with minimal microbial activity (indicated by low rates of sulfate loss), the addition of either dissolved Hg or nano-HgS resulted in similar amounts of net MeHg production. For all slurries receiving micro-HgS, MeHg production did not exceed abiotic controls. In slurries amended with dissolved and nano-HgS, mercury was mainly partitioned to bulk-scale mineral particles and colloids, indicating that Hg bioavailability was not simply related to dissolved Hg concentration or speciation. Overall, the results suggest that models for mercury methylation potential in the environment will need to balance the relative contributions of

  16. Aerobic Biotransformation of Fluorotelomer Thioether Amido Sulfonate (Lodyne) in AFFF-Amended Microcosms.

    PubMed

    Harding-Marjanovic, Katie C; Houtz, Erika F; Yi, Shan; Field, Jennifer A; Sedlak, David L; Alvarez-Cohen, Lisa

    2015-07-01

    The aerobic biotransformation pathways of 4:2, 6:2, and 8:2 fluorotelomer thioether amido sulfonate (FtTAoS) were characterized by determining the fate of the compounds in soil and medium microcosms amended with an aqueous film-forming foam (AFFF) solution. The biotransformation of FtTAoS occurred in live microcosms over approximately 40 days and produced 4:2, 6:2, and 8:2 fluorotelomer sulfonate (FtS), 6:2 fluorotelomer unsaturated carboxylic acid (FtUCA), 5:3 fluorotelomer carboxylic acid (FtCA), and C4 to C8 perfluorinated carboxylic acids (PFCAs). Two biotransformation products corresponding to singly and doubly oxygenated forms of 6:2 FtTAoS were also identified through high resolution mass spectrometry (MS) analysis and liquid chromatography tandem-MS. An oxidative assay was used to indirectly quantify the total concentration of polyfluorinated compounds and check the mass balance. The assay produced near complete mass recovery of FtTAoS after biotransformation, with 10% (mol/mol) of the amended FtTAoS accounted for in FtS, FtCA, and PFCA products. The transformation rates of identified products appear to be slow relative to FtTAoS, indicating that some intermediates may persist in the environment. This study confirms some of the sources of FtS and PFCAs in groundwater and soil at AFFF-impacted sites and suggests that fluorinated intermediates that are not routinely measured during the biotransformation of PFASs may accumulate. PMID:26042823

  17. Fostering Activities of Daily Living by Intact Nursing Home Residents

    ERIC Educational Resources Information Center

    Blair, Charles E.; Glaister, Judy; Brown, Alston; Phillips, Carolyn

    2007-01-01

    We assessed effectiveness of four education programs in providing nursing assistants with ability to produce a therapeutic milieu supportive of intact residents' activities of daily living, positive self-esteem and mood: (1) a combination of Orem's Systems of Nursing Care and Skinner's Applied Behavioral Analysis, (2) Applied Behavioral Analysis,…

  18. ROOTBOX FOR QUANTITATIVE OBSERVATIONS ON INTACT ENTIRE ROOT SYSTEMS

    EPA Science Inventory

    A rootbox is described which allows observation of an intact, entire root system. oots are sandwiched against a plexiglass surface by a nylon mesh that is impermeable to roots, but permeable to water and nutrients. o quantify root growth non-destructively, roots of different size...

  19. 46 CFR 174.045 - Intact stability requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Mobile Offshore Drilling Units § 174.045 Intact stability requirements. (a) Each unit must be designed so that the wind heeling moments (Hm) and... downflooding would occur, whichever angle is less; and (3) Area (B) is the area on GRAPH 174.045 under the...

  20. 46 CFR 174.045 - Intact stability requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Mobile Offshore Drilling Units § 174.045 Intact stability requirements. (a) Each unit must be designed so that the wind heeling moments (Hm) and... downflooding would occur, whichever angle is less; and (3) Area (B) is the area on GRAPH 174.045 under the...

  1. 46 CFR 174.045 - Intact stability requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Mobile Offshore Drilling Units § 174.045 Intact stability requirements. (a) Each unit must be designed so that the wind heeling moments (Hm) and... downflooding would occur, whichever angle is less; and (3) Area (B) is the area on GRAPH 174.045 under the...

  2. 46 CFR 174.045 - Intact stability requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Mobile Offshore Drilling Units § 174.045 Intact stability requirements. (a) Each unit must be designed so that the wind heeling moments (Hm) and... downflooding would occur, whichever angle is less; and (3) Area (B) is the area on GRAPH 174.045 under the...

  3. Phosphorylation of intact erythrocytes in human muscular dystrophy

    SciTech Connect

    Johnson, R.M.; Nigro, M.

    1986-04-01

    The uptake of exogenous /sup 32/Pi into the membrane proteins of intact erythrocytes was measured in 8 patients with Duchenne muscular dystrophy. No abnormalities were noted after autoradiographic analysis. This contrasts with earlier results obtained when isolated membranes were phosphorylated with gamma-(/sup 32/P)ATP, and suggests a possible reinterpretation of those experiments.

  4. 50 CFR 622.381 - Landing fish intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Coastal Migratory Pelagic Resources (Gulf of Mexico and South Atlantic) § 622.381 Landing fish intact. (a) Cobia, king mackerel, and Spanish mackerel in or from the Gulf, Mid-Atlantic, or South Atlantic EEZ, except...

  5. 50 CFR 622.381 - Landing fish intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Coastal Migratory Pelagic Resources (Gulf of Mexico and South Atlantic) § 622.381 Landing fish intact. (a) Cobia, king mackerel, and Spanish mackerel in or from the Gulf, Mid-Atlantic, or South Atlantic EEZ, except...

  6. Pharmacokinetics of erythropoietin in intact and anephric dogs

    SciTech Connect

    Fu, J.S.; Lertora, J.J.; Brookins, J.; Rice, J.C.; Fisher, J.W.

    1988-06-01

    The present studies were performed to determine the pharmacokinetic parameters of erythropoietin in intact and anephric dogs by use of unlabeled crude native erythropoietin (nEp) and iodine 125-labeled purified recombinant erythropoietin (rEp) given by intravenous infusion for 15 minutes. Sephadex G-75 gel filtration was used to confirm that the 125I-rEp molecule remained iodinated in dog plasma during the 24-hour period of these studies. The plasma disappearance of erythropoietin conformed to a biexponential equation for both nEp and 125I-rEp, with the central compartment being larger than the peripheral compartment. The mean distribution half-life of 75.3 +/- 21.2 minutes for nEp was significantly (p less than 0.05) longer than that of 125I-rEp (23.7 +/- 5.0 minutes) in intact dogs. The intercompartmental clearance (CIic) for nEp (0.018 +/- 0.006 L/kg/hr) was significantly smaller than that of 125I-rEp (0.068 +/- 0.018 L/kg/hr) in intact dogs (p less than 0.05). There were no significant differences in apparent volume of distribution, elimination half-life, and elimination clearance (CIe) for nEp and rEp in intact dogs. The mean elimination half-life for 125I-rEp in intact dogs (9.0 +/- 0.6 hours) and anephric dogs (13.8 +/- 1.4 hours) was significantly different (p less than 0.05). The CIe for 125I-rEp in anephric dogs (0.008 +/- 0.001 L/kg/hr) was significantly (p less than 0.05) smaller than that of 125I-rEp in intact dogs (0.011 +/- 0.001 L/kg/hr). There were no significant differences in apparent volume of distribution, distribution half-life, and CIic for 125I-rEp in intact and anephric dogs.

  7. In-situ Subaqueous Capping of Mercury-Contaminated Sediments in a Fresh-Water Aquatic System, Part I-Bench-Scale Microcosm Study to Assess Methylmercury Production

    EPA Science Inventory

    Bench-scale microcosm experiments were designed to provide a better understanding of the potential for Hg methylation in sediments from an aquatic environment. Experiments were conducted to examine the function of sulfate concentration, lactate concentration, the presence/absenc...

  8. A Retrievable Mineral Microcosm for Examining Microbial Colonization and Mineral Precipitation at Seafloor Hydrothermal Vents

    NASA Astrophysics Data System (ADS)

    Dunn, E. E.; Holloway, J. R.; Cary, S.; Voglesonger, K. M.; Ashbridge, D. A.; O'Day, P. A.

    2002-12-01

    Although seafloor hydrothermal vent environments are known to support thriving ecosystems, the microscale physical and chemical environment suitable for microbial colonization and the identity of pioneering organisms is unknown. Because of the fragility of young chimneys and their ephemeral nature, novel methods for sample retrieval and analysis are required. The mineral microcosm consists of four titanium mesh chambers containing crushed minerals mounted on a titanium base that allows for fluid flow through the chambers. The chambers can be filled with different minerals or mineral mixtures (or no minerals) to supply different substrates for microbial colonization and different local microenvironments as minerals react with the surrounding fluids. The device sets on top of an active hydrothermal vent for a period of days to weeks to allow colonization and mineral reaction. The mineral microcosm was deployed during the Atlantis/Alvin Extreme 2001 Cruise (Oct.- Nov.,2001) to 9° 50'N on the East Pacific Rise a total of three times, for ~ 24, ~ 96, and ~ 48 hours each. It was deployed in two different environments, twice in lower temperature (<300°C), diffuse-flow environments and once (for ~96 hours) in a higher temperature black smoker environment (>350°C).Seed minerals included sulfides, sulfates, magnetite, apatite, and quartz, both individually and in mixtures. In the first 24-hour deployment, dissolution of anhydrite but not sulfide minerals within the chambers indicated high temperatures in chamber interiors and rapid reaction rates. Temperatures measured on chamber exteriors before retrieval ranged from 4° -98°C. The 96-hour deployment on a hot vent (fluid ~370°C before deployment) resulted in extensive mineral precipitation and chimney growth inside the mineral chambers, on the outer surfaces of the chambers, and on the platform as a whole, creating micro-chimneys several centimeters tall. The young chimneys were mainly composed of pyrite with lesser

  9. The Multilevel Mixed Intact Group Analysis: A Mixed Method to Seek, Detect, Describe, and Explain Differences Among Intact Groups

    ERIC Educational Resources Information Center

    Schoonenboom, Judith

    2016-01-01

    Educational innovations often involve intact subgroups, such as school classes or university departments. In small-scale educational evaluation research, typically involving 1 to 20 subgroups, differences among these subgroups are often neglected. This article presents a mixed method from a qualitative perspective, in which differences among…

  10. The MICROBE (Microcosm Investigation of Carbonate Reef/Ocean Microbial Biogeochemistry & Ecology) Project

    NASA Astrophysics Data System (ADS)

    Hannides, A. K.; Gaidos, E. J.; Sansone, F. J.

    2003-12-01

    We present a methodology to manipulate carbonate reef sediments in order to study the geochemical and microbiological response of reef systems to perturbations. We specifically plan to study the effects of changes in the atmospheric partial pressure of CO2. Our laboratory set-up will consist of cores containing carbonate reef sediments and overlying water. These microcosms are designed to replicate the gross hydraulic and geochemical characteristics of sediments in a natural tropical reef patch. This is achieved by reproducing the advective transport of water and particulates in and out of the sediments induced by tides and surface waves. Seawater from nearby reefs is to be introduced into the cores with reversible peristaltic pumps. The pumps will vary the overlying water column and simulate the changes in hydrostatic head that accompany waves and tides. The parameters characterizing these oscillations will be set at values reflecting those at nearby natural settings. Sediment column characteristics will be determined non-destructively through openings at various depths down the sediment cores. These openings are fitted with rubber septa and shut-off valves, which allow gas-tight sampling of porewaters. An additional set of openings allows for the removal of small amounts of sediments using augers. Our porewater analyses will include dissolved O2, CO2, CH4 and alkalinity, ammonium, sulfide, and iron and manganese ions. Our solid phase analyses will include carbonate composition and framework structure, and iron and manganese abundances in the carbonate phases. We will measure microbial abundance in porewater and the sediment particles by DAPI cell counts and will assay community composition using Denaturing Gradient Gel Electrophoresis (DGGE). Our goal is to use this methodology to observe and record carbonate precipitation and dissolution by microbiota under varying carbon dioxide regimes. pCO2 concentrations will be manipulated by bubbling a N2/CO2 mixture

  11. Synergy in microcosms with environmentally realistic concentrations of prochloraz and esfenvalerate.

    PubMed

    Bjergager, Maj-Britt A; Hanson, Mark L; Lissemore, Linda; Henriquez, Nikki; Solomon, Keith R; Cedergreen, Nina

    2011-01-25

    Laboratory experiments have shown that azole fungicides enhance the toxic effect of pyrethroid insecticides towards the aquatic crustacean Daphnia magna. Due to their sorptive properties the pesticides may, however, be less bioavailable in natural environments, possibly rendering them less toxic to aquatic organisms. In the present study, the synergistic potential of azoles on pyrethroids in natural environments was assessed by treating 18 outdoor aquatic microcosms with concentrations of the pyrethroid esfenvalerate at 0.167, 0.333, or 0.833μg/L either alone or in combination with 90μg/L of the azole prochloraz. Pesticide concentrations and the zooplankton and phytoplankton communities were assessed prior to pesticide application and at days 0, 1, 2, 4, 7, 14, 21, and 28 after pesticide application. DT(50)-values for disappearance of the pesticides from the water of 4.7 days and 30h were observed for prochloraz and esfenvalerate, respectively. The monitored communities showed larger decreases in abundance of cladoceran, copepods, and chironomids in treatments with esfenvalerate in combination with prochloraz compared to treatments with esfenvalerate alone. No systematic effects were observed in populations of Ostracoda. Adverse effects on populations of cladocerans and copepods occurred between day 2 and day 7 and, though copepods in general were less sensitive than cladocerans to both esfenvalerate alone and in combination with prochloraz, the potentiation factors for the two taxa were similar. Thus, comparison of EC(20)-values estimated on the basis of concentration-response curves for days 2, 4, and 7 showed that prochloraz enhanced the toxicity of esfenvalerate four to sixfold for copepods and three to sevenfold for cladocerans. Rotifers were not significantly affected by any of the treatments, though there was a tendency of a population increase when cladoceran and copepod populations decreased. In all invertebrate populations that showed response to the

  12. Biodegradation of organic chemicals in soil/water microcosms system: Model development

    USGS Publications Warehouse

    Liu, L.; Tindall, J.A.; Friedel, M.J.; Zhang, W.

    2007-01-01

    The chemical interactions of hydrophobic organic contaminants with soils and sediments may result in strong binding and slow subsequent release rates that significantly affect remediation rates and endpoints. In order to illustrate the recalcitrance of chemical to degradation on sites, a sorption mechanism of intraparticle sequestration was postulated to operate on chemical remediation sites. Pseudo-first order sequestration kinetics is used in the study with the hypothesis that sequestration is an irreversibly surface-mediated process. A mathematical model based on mass balance equations was developed to describe the fate of chemical degradation in soil/water microcosm systems. In the model, diffusion was represented by Fick's second law, local sorption-desorption by a linear isotherm, irreversible sequestration by a pseudo-first order kinetics and biodegradation by Monod kinetics. Solutions were obtained to provide estimates of chemical concentrations. The mathematical model was applied to a benzene biodegradation batch test and simulated model responses correlated well compared to measurements of biodegradation of benzene in the batch soil/water microcosm system. A sensitivity analysis was performed to assess the effects of several parameters on model behavior. Overall chemical removal rate decreased and sequestration increased quickly with an increase in the sorption partition coefficient. When soil particle radius, a, was greater than 1 mm, an increase in radius produced a significant decrease in overall chemical removal rate as well as an increase in sequestration. However, when soil particle radius was less than 0.1 mm, an increase in radius resulted in small changes in the removal rate and sequestration. As pseudo-first order sequestration rate increased, both chemical removal rate and sequestration increased slightly. Model simulation results showed that desorption resistance played an important role in the bioavailability of organic chemicals in porous

  13. Microbial Community Phylogenetic and Functional Succession in Chromium-Reducing Aquifer-Derived Microcosms

    NASA Astrophysics Data System (ADS)

    Brodie, E. L.; Beller, H. R.; Goldfarb, K. C.; Han, R.; Santee, C. A.

    2009-12-01

    In situ reductive immobilization, whereby highly soluble Cr(VI) species are reduced to poorly soluble Cr(III) species, is a favored approach for remediating Cr-contaminated groundwater. How microbial populations respond phylogenetically and functionally to the injection of an organic electron donor to stimulate Cr(VI) reduction is unclear, as are the relative contributions of direct enzymatic Cr(VI) reduction versus indirect (e.g. sulfide-mediated) reduction. In this study, we inoculated anaerobic microcosms with groundwater from the Cr-contaminated Hanford 100H site (WA) and supplemented them with lactate and the electron acceptors nitrate, sulfate, and amorphous ferric oxyhydroxide. The microcosms progressed successively through nitrate-reducing, sulfate-reducing, and Fe(III)-reducing conditions, and after a second nitrate amendment, nitrate-dependent Fe(II)-oxidizing conditions. Cr(VI) reduction occurred during both the denitrification and the sulfate/iron reduction phases. DNA and RNA were harvested during each major biogeochemical phase and were subjected to PhyloChip analysis, qPCR, and transcript sequencing. Bacterial community succession followed a trajectory related to the sequential use of electron acceptors. During denitrification, bacterial communities were enriched in known denitrifiers within the Beta- and Gamma-proteobacteria and became phylogenetically clustered. Fermenters became enriched following nitrate reduction, preceding both iron and sulfate reduction. Iron reduction was stoichiometrically related to the formation of hydrogen sulfide and, although iron reducers were detected during this phase, their iron-reducing activity was not confirmed. Following the depletion of lactate and sulfate, iron reduction rates decreased and acetate and propionate concentrations stabilized, indicating a marginal contribution of acetate-coupled iron reduction. Rapid Fe(II) oxidation occurred following the nitrate amendment with a concomitant reduction of nitrate

  14. The effects of high-tannin leaf litter from transgenic poplars on microbial communities in microcosm soils

    PubMed Central

    Winder, Richard S.; Lamarche, Josyanne; Constabel, C. Peter; Hamelin, Richard C.

    2013-01-01

    The impacts of leaf litter from genetically modified hybrid poplar accumulating high levels of condensed tannins (proanthocyanidins) were examined in soil microcosms consisting of moss growing on sieved soil. Moss preferentially proliferated in microcosms with lower tannin content; DGGE (denaturing gradient gel electrophoresis) detected increased fungal diversity in microcosms with low-tannin litter. The proportion of cloned rDNA sequences from Actinobacteria decreased with litter addition while Bacteroidetes, Chloroflexi, Cyanobacteria, and α-Proteobacteria significantly increased. β-Proteobacteria were proportionally more numerous at high-tannin levels. Tannins had no significant impact on overall diversity of bacterial communities analyzed with various estimators. There was an increased proportion of N-fixing bacteria corresponding to the addition of litter with low-tannin levels. The addition of litter increased the proportion of Ascomycota/Basidiomycota. Dothideomycetes, Pucciniomycetes, and Tremellomycetes also increased and Agaricomycetes decreased. Agaricomycetes and Sordariomycetes were significantly more abundant in controls, whereas Pucciniomycetes increased in soil with litter from transformed trees (P = 0.051). Richness estimators and diversity indices revealed no significant difference in the composition of fungal communities; PCoA (principal coordinate analyses) partitioned the fungal communities into three groups: (i) those with higher amounts of added tannin from both transformed and untransformed treatments, (ii) those corresponding to soils without litter, and (iii) those corresponding to microcosms with litter added from trees transformed only with a β-glucuronidase control vector. While the litter from transformed poplars had significant effects on soil microbe communities, the observed impacts reflected known impacts on soil processes associated with tannins, and were similar to changes that would be expected from natural variation in

  15. Influence of organic waste type and soil structure on the bacterial filtration rates in unsaturated intact soil columns.

    PubMed

    Mosaddeghi, M R; Mahboubi, A A; Zandsalimi, S; Unc, A

    2009-02-01

    Organic wastes are considered to be a source for the potentially pathogenic microorganisms found in surface and sub-surface water resources. Following their release from the organic waste matrix, bacteria often infiltrate into soil and may be transported to significant depths contaminating aquifers. We investigated the influence of soil texture and structure and most importantly the organic waste properties on the transport and filtration coefficients of Escherichia coli and total bacteria in undisturbed soil columns. Intact soil columns (diameter 16 cm and height 25 cm) were collected from two soils: sandy clay loam (SCL) and loamy sand (LS) in Hamadan, western Iran. The cores were amended with cow manure, poultry manure and sewage sludge at a rate of 10 Mg ha(-1) (dry basis). The amended soil cores were leached at a steady-state flux of 4.8 cm h(-1) (i.e. 0.12 of saturated hydraulic conductivity of the SCL) to a total volume of up to 4 times the pore volume of the columns. The influent (C(0)) and effluent (C) were sampled at similar time intervals during the experiments and bacterial concentrations were measured by the plate count method. Cumulative numbers of the leached bacteria, filtration coefficient (lambda(f)), and relative adsorption index (S(R)) were calculated. The preferential pathways and stable structure of the SCL facilitated the rapid transport and early appearance of the bacteria in the effluent. The LS filtered more bacteria when compared with the SCL. The effluent contamination of poultry manure-treated columns was greater than the cow manure- and sewage sludge-treated ones. The difference between cow manure and sewage sludge was negligible. The lambda(f) and S(R) values for E. coli and total bacteria were greater in the LS than in the SCL. This indicates a predominant role for the physical pore-obstruction filtration mechanisms as present in the poorly structured LS vs. the retention at adsorptive sites (chemical filtration) more likely in the

  16. Effects of Eichhornia crassipes and Ceratophyllum demersum on Soil and Water Environments and Nutrient Removal in Wetland Microcosms.

    PubMed

    Sung, Kijune; Lee, Geun-Joo; Munster, Clyde

    2015-01-01

    Wetland plants are important components that influence the biogeochemistry of wetland ecosystems. Therefore, remediation performance in wetlands can differ depending on the growth forms of plants. In this study, the effects of Eichhornia crassipes (floating plant) and Ceratophyllum demersum (submerged plant) on the wetland soil and water environments were investigated using a microcosm study with simulated hydrology of retention-type wetlands between rainfall events. The C. demersum microcosm (SP) showed the fastest recovery with a diel fluctuation pattern of dissolved oxygen, pH, and oxidation-reduction potential (ORP) from the impacts of nutrient inflow. Moreover, SP exhibited the lowest decrease in sediment ORP, the highest dehydrogenase activity, and more organic forms of nitrogen and phosphorus. E. crassipes microcosms exhibited the lowest water temperature, and efficiently controlled algae. In the presence of plants, the total nitrogen and phosphorus concentrations in water rapidly decreased, and the composition of organic and inorganic nutrient forms was altered along with a decrease in concentration. The results indicate that wetland plants help retain nutrients in the system, but the effects varied based on the wetland plant growth forms. PMID:25581097

  17. Determining the effects of pollutants on soil faunal communities and trophic structure using a refined microcosm system

    SciTech Connect

    Parmelee, R.W.; Phillips, C.T.; Checkai, R.T.; Bohlen, P.J.

    1997-06-01

    The authors used a refined microcosm technique to investigate the toxicity of copper, cadmium, malathion, and the polychlorinated biphenyl, to trophic groups of soil nematodes and to the microarthropod community. Comparisons of changes in nematode abundance in control soils through time indicated that day 7 was the most appropriate time to sample the microcosms after chemical application. Nematode abundance was reduced after exposure to copper at 100 {micro}g/g, with fungivore, bacterivore, and omnivore-predator nematodes being the most sensitive groups. Cadmium did not affect the nematode or microarthropod communities. Microarthropods were far more sensitive to malathion than were nematodes, and total microarthropod abundance was lower than controls at 400 {micro}g/g. Prostigmatid mites and other arthropods were the most affected groups. PCB also had a greater negative impact on microarthropods than on nematodes. Total microarthropod abundance declined at 2,500 {micro}g/g, with prostigmatid and oribatid mites exhibiting the highest susceptibility. Strong differential sensitivity between nematode and microarthropod communities indicates that both groups should be examined to fully evaluate the biological impact of chemicals on soils. The authors conclude that microcosms with field-collected soil microfaunal communities offer high resolution of the ecotoxicologic effects of chemicals in complex soil systems.

  18. Identification of transformation products from β-blocking agents formed in wetland microcosms using LC-Q-ToF.

    PubMed

    Svan, Alfred; Hedeland, Mikael; Arvidsson, Torbjörn; Jasper, Justin T; Sedlak, David L; Pettersson, Curt E

    2016-03-01

    Identification of degradation products from trace organic compounds, which may retain the biological activity of the parent compound, is an important step in understanding the long-term effects of these compounds on the environment. Constructed wetlands have been successfully utilized to remove contaminants from wastewater effluent, including pharmacologically active compounds. However, relatively little is known about the transformation products formed during wetland treatment. In this study, three different wetland microcosm treatments were used to determine the biotransformation products of the β-adrenoreceptor antagonists atenolol, metoprolol and propranolol. LC/ESI-Q-ToF run in the MS(E) and MS/MS modes was used to identify and characterize the degradation products through the accurate masses of precursor and product ions. The results were compared with those of a reference standard when available. Several compounds not previously described as biotransformation products produced in wetlands were identified, including propranolol-O-sulfate, 1-naphthol and the human metabolite N-deaminated metoprolol. Transformation pathways were significantly affected by microcosm conditions and differed between compounds, despite the compounds' structural similarities. Altogether, a diverse range of transformation products in wetland microcosms were identified and elucidated using high resolving MS. This work shows that transformation products are not always easily predicted, nor formed via the same pathways even for structurally similar compounds. PMID:26956388

  19. Stimulation of anaerobic biodegradation of DDT and its metabolites in a muck soil: laboratory microcosm and mesocosm studies.

    PubMed

    Gohil, Hiral; Ogram, Andrew; Thomas, John

    2014-09-01

    The aim of this study was to evaluate the impact of selected electron donors and electron acceptors on the anaerobic biodegradation of DDT and its major metabolites in a muck soil with a long history of exposure to the pesticide. Loss of DDT was measured in anaerobic microcosms supplemented with H2, lactate, and acetate. The greatest loss of DDT (approximately 87 %) was observed in microcosms amended with lactate and no additional electron acceptor compared to the no additional electron donor or acceptor sets. An increase in measureable concentrations of DDx was observed in un-amended microcosms. In larger scale mesocosms, significant increases in dissolved organic carbon (DOC) corresponded with low redox potentials. Increases in DOC corresponded with sharp increases in measured concentrations of DDx, followed by a decrease in measured DDT concentrations in lactate-amended mesocosms. Our studies indicate that sorbed DDx is released upon anaerobic incubation, and that indigenous microorganisms capable of DDx degradation respond to lactate additions. Both the potential for release of sorbed DDx and the potential for biodegradation of DDx should be considered during remediation of DDx-contaminated organic soils at low redox potentials. PMID:24584703

  20. The influence of nickel on the bioremediation of multi-component contaminated tropical soil: microcosm and batch bioreactor studies.

    PubMed

    Taketani, Natália Franco; Taketani, Rodrigo Gouvêa; Leite, Selma Gomes Ferreira; Rizzo, Andrea Camardella de Lima; Tsai, Siu Mui; da Cunha, Cláudia Duarte

    2015-07-01

    Large petrochemical discharges are responsible for organic and inorganic pollutants in the environment. The purpose of this study was to evaluate the influence of nickel, one of the most abundant inorganic element in crude oil and the main component of hydrogen catalysts for oil refining, on the microbial community structure in artificially petroleum-contaminated microcosms and in solid phase bioreactor studies. In the presence of metals, the oil biodegradation in microcosms was significantly delayed during the first 7 days of operation. Also, increasing amounts of moisture generated a positive influence on the biodegradation processes. The oil concentration, exhibiting the most negative influence at the end of the treatment period. Molecular fingerprinting analyses (denaturing gradient gel electrophoresis--DGGE) indicated that the inclusion of nickel into the contaminated soil promoted direct changes to the microbial community structure. By the end of the experiments, the results of the total petroleum hydrocarbons removal in the bioreactor and the microcosm were similar, but reductions in the treatment times were observed with the bioreactor experiments. An analysis of the microbial community structure by DGGE using various markers showed distinct behaviors between two treatments containing high nickel concentrations. The main conclusion of this study was that Nickel promotes a significant delay in oil biodegradation, despite having only a minor effect over the microbial community. PMID:25940327

  1. Fate of Viable but Non-culturable Listeria monocytogenes in Pig Manure Microcosms.

    PubMed

    Desneux, Jérémy; Biscuit, Audrey; Picard, Sylvie; Pourcher, Anne-Marie

    2016-01-01

    The fate of two strains of Listeria monocytogenes and their ability to become viable but non-culturable (VBNC) was investigated in microcosms containing piggery effluents (two raw manures and two biologically treated manures) stored for 2 months at 8 and 20°C. Levels of L. monocytogenes were estimated using the culture method, qPCR, and propidium monoazide treatment combined with qPCR (qPCRPMA). The chemical composition and the microbial community structure of the manures were also analyzed. The strains showed similar decline rates and persisted up to 63 days. At day zero, the percentage of VBNC cells among viable cells was higher in raw manures (81.5-94.8%) than in treated manures (67.8-79.2%). The changes in their proportion over time depended on the temperature and on the type of effluent: the biggest increase was observed in treated manures at 20°C and the smallest increase in raw manures at 8°C. The chemical parameters had no influence on the behavior of the strains, but decrease of the persistence of viable cells was associated with an increase in the microbial richness of the manures. This study demonstrated that storing manure altered the culturability of L. monocytogenes, which rapidly entered the VBNC state, and underlines the importance of including VBNC cells when estimating the persistence of the pathogens in farm effluents. PMID:26973623

  2. Microcosm studies of the role of land plants in elevating soil carbon dioxide and chemical weathering

    NASA Astrophysics Data System (ADS)

    Baars, C.; Hefin Jones, T.; Edwards, Dianne

    2008-09-01

    A decrease in atmospheric carbon dioxide (CO2) concentration during the mid-Palaeozoic is postulated to have been partially the consequence of the evolution of rooted land plants. Root development increased the amount of carbonic acid generated by root respiration within soils. This led to increased chemical weathering of silicates and subsequent formation of carbonates, resulting in lower atmospheric CO2 concentrations. To test this assumption, analog (morphologically equivalent) plant species, ranging from those possessing no roots to those with complex rhizomatous rooting systems, were grown in trays within microcosms at ambient (360 ppm/0.37 mbar) and highly elevated (3500 ppm/3.55 mbar) atmospheric CO2 concentrations in a controlled environment facility. Substrate CO2 concentrations increased significantly under elevated atmospheric CO2, and Equisetum hyemale (L.). The latter is postulated to result from the effects of deeply rooted plants, elevated atmospheric CO2 concentrations, or both. Plants with simple or no rooting systems or the addition of dead organic matter as a substrate for microorganisms did not enhance substrate CO2 concentrations.

  3. Applicability of Hydrogen Peroxide in Brown Tide Control – Culture and Microcosm Studies

    PubMed Central

    Randhawa, Varunpreet; Thakkar, Megha; Wei, Liping

    2012-01-01

    Brown tide algal blooms, caused by the excessive growth of Aureococcus anophagefferens, recur in several northeastern US coastal bays. Direct bloom control could alleviate the ecological and economic damage associated with bloom outbreak. This paper explored the effectiveness and safety of natural chemical biocide hydrogen peroxide (H2O2) for brown tide bloom control. Culture studies showed that H2O2 at 1.6 mg L−1 effectively eradicated high density A. anophagefferens within 24-hr, but caused no significant growth inhibition in the diatoms, prymnesiophytes, green algae and dinoflagellates of >2–3 μm cell sizes among 12 phytoplankton species tested over 1-week observation. When applied to brown tide bloom prone natural seawater in a microcosm study, this treatment effectively removed the developing brown tide bloom, while the rest of phytoplankton assemblage (quantified via HPLC based marker pigment analyses), particularly the diatoms and green algae, experienced only transient suppression then recovered with total chlorophyll a exceeding that in the controls within 72-hr; cyanobacteria was not eradicated but was still reduced about 50% at 72-hr, as compared to the controls. The action of H2O2 against phytoplankton as a function of cell size and cell wall structure, and a realistic scenario of H2O2 application were discussed. PMID:23082223

  4. The corrosion of carbon steel in rock microcosms containing native Yucca Mountain microorganisms

    SciTech Connect

    Castro, P.R.; Amy, P.S.; Crossen, H.V.; Jones, D.A.; Southam, G.; Donald, R.; Ringelberg, D.B.

    1998-12-31

    Microorganisms implicated in microbially-influenced corrosion were isolated from the deep subsurface at Yucca Mountain, and include iron-oxidizing (FeOx), sulfate-reducing (SRB), and exopolysaccharide (EPS)-producing bacterial species. Various combinations of these microorganisms were inoculated into a test system composed of a 1020 carbon steel coupon immersed in a mixture of sterile rock and soft R2A agar prepared with simulated groundwater. A 1% KC1 bridge was used to connect the test system to a calomel reference electrode. A platinum counter electrode was used to apply a potential and the corrosion rate was measured by polarization resistance. Prior studies at ambient and elevated (50 C) temperatures demonstrated that these microorganisms were capable of corroding carbon steel. The current research investigated whether the presence of a rock surface enhanced the ability of the test microorganisms to survive elevated temperature and corrode carbon steel. Uninoculated electrochemical cells were prepared to monitor abiotic corrosion. Initial and weekly corrosion rates were obtained for the duration of the experiment. Upon completion of the experiment, the test system was dismantled and the coupons prepared for phospholipid fatty acid and microscopic analyses, to assess microbial biomass and biofilm formation, respectively. Increased biomass and higher corrosion rates were observed in the rock/agar microcosms.

  5. Microcosm study on fate of polybrominated diphenyl ethers (PBDEs) in contaminated mangrove sediment.

    PubMed

    Zhu, Haowen; Wang, Ying; Tam, Nora F Y

    2014-01-30

    Polybrominated diphenyl ethers (PBDEs) are toxic and ubiquitous environmental contaminants, but their fate in aquatic environments is not clear. A mangrove microcosm study was employed to investigate the fate of two abundant congeners, BDE-47 and BDE-209, in contaminated sediment. After seven months, more than 90% of the spiked BDE-47 in the mangrove sediment was removed with the formation of lower brominated PBDEs, including BDE-28, -17, -15, -8, -7/4, suggesting that microbial debromination was the main contributor. Debromination of BDE-209 was also observed in the sediment but its dissipation rate was significantly lower than BDE-47. All these congeners were taken up, translocated and accumulated into the tissues of two typical mangrove plants, Kandelia obovata and Avicennia marina. PBDEs, even at very high contamination levels, in the sediment (5000ngg(-1)) and the debrominated congeners did not pose any adverse effect on the dry weight, augmentation and root/shoot ratio of either mangrove species. This is the first study to reveal that anaerobic microbial debromination and uptake by mangrove plants are the key processes controlling the fate of PBDEs in mangrove sediment. PMID:24333715

  6. Hydrologic Variability Affects Invertebrate Grazing on Phototrophic Biofilms in Stream Microcosms

    PubMed Central

    Ceola, Serena; Hödl, Iris; Adlboller, Martina; Singer, Gabriel; Bertuzzo, Enrico; Mari, Lorenzo; Botter, Gianluca; Waringer, Johann; Battin, Tom J.; Rinaldo, Andrea

    2013-01-01

    The temporal variability of streamflow is known to be a key feature structuring and controlling fluvial ecological communities and ecosystem processes. Although alterations of streamflow regime due to habitat fragmentation or other anthropogenic factors are ubiquitous, a quantitative understanding of their implications on ecosystem structure and function is far from complete. Here, by experimenting with two contrasting flow regimes in stream microcosms, we provide a novel mechanistic explanation for how fluctuating flow regimes may affect grazing of phototrophic biofilms (i.e., periphyton) by an invertebrate species (Ecdyonurus sp.). In both flow regimes light availability was manipulated as a control on autotroph biofilm productivity and grazer activity, thereby allowing the test of flow regime effects across various ratios of biofilm biomass to grazing activity. Average grazing rates were significantly enhanced under variable flow conditions and this effect was highest at intermediate light availability. Our results suggest that stochastic flow regimes, characterised by suitable fluctuations and temporal persistence, may offer increased windows of opportunity for grazing under favourable shear stress conditions. This bears important implications for the development of comprehensive schemes for water resources management and for the understanding of trophic carbon transfer in stream food webs. PMID:23613735

  7. Area V5—a microcosm of the visual brain

    PubMed Central

    Zeki, Semir

    2015-01-01

    Area V5 of the visual brain, first identified anatomically in 1969 as a separate visual area, is critical for the perception of visual motion. As one of the most intensively studied parts of the visual brain, it has yielded many insights into how the visual brain operates. Among these are: the diversity of signals that determine the functional capacities of a visual area; the relationship between single cell activity in a specialized visual area and perception of, and preference for, attributes of a visual stimulus; the multiple asynchronous inputs into, and outputs from, an area as well as the multiple operations that it undertakes asynchronously; the relationship between activity at given, specialized, areas of the visual brain and conscious awareness; and the mechanisms used to “bind” signals from one area with those from another, with a different specialization, to give us our unitary perception of the visual world. Hence V5 is, in a sense, a microcosm of the visual world and its study gives important insights into how the whole visual brain is organized—anatomically, functionally and perceptually. PMID:25883556

  8. Fatigue characteristics and microcosmic mechanism of Al-Si-Mg alloys under multiaxial proportional loadings

    NASA Astrophysics Data System (ADS)

    Jiang, Xiao-Song; He, Guo-Qiu; Liu, Bing; Zhu, Zheng-Yu; Zhang, Wei-Hua

    2011-08-01

    With the increasing use of Al-Si-Mg alloys in the automotive industry, the fatigue performance of Al-Si-Mg alloy has become a major concern with regard to their reliability. The fatigue characteristics and microcosmic mechanism of an Al-Si-Mg alloy under multiaxial proportional loadings were investigated in this research. As low cycle fatigue life and material strengthening behavior are closely related, the effect of equivalent strain amplitude on the multiaxial fatigue properties was analyzed. Fatigue tests were conducted to determine the influence of equivalent strain amplitude on the multiaxial proportional fatigue properties. The fatigue life exhibits a stable behavior under multiaxial proportional loadings. The dislocation structures of the Al-Si-Mg alloy were observed by transmission electron microscopy (TEM). The dislocation structure evolution of the Al-Si-Mg alloy under multiaxial proportional loadings during low cycle fatigue develops step by step by increasing fatigue cycles. Simultaneously, the dislocation structure changes with the change in equivalent strain amplitude under multiaxial proportional loadings. The experimental evidence indicates that the multiaxial fatigue behavior and life are strongly dependent on the microstructure of the material, which is caused by multiaxial proportional loadings.

  9. The dynamics of community assembly under sudden mixing in experimental microcosms.

    PubMed

    Livingston, George; Jiang, Yuexin; Fox, Jeremy W; Leibold, Mathew A

    2013-12-01

    Landscape connectivity has been shown to alter community assembly and its consequences. Here we examine how strong, sudden changes in connectivity may affect community assembly by conducting experiments on the effects of "community mixing," situations where previously isolated communities become completely connected with consequent community reorganization. Previous theory indicates that assembly history dictates the outcome of mixing: mixing randomly assembled communities leads to a final community with random representation from the original communities, while mixing communities that were assembled via a long history of colonizations and extinctions leads to strong asymmetry, with one community dominating the other. It also predicts that asymmetry should be stronger in the presence of predators in the system. We experimentally tested and explored this theory by mixing aquatic microcosms inhabited by a complex food web of heterotrophic protists, and algae. Our results confirm the prediction that long assembly history can produce asymmetry under mixing and suggest these dynamics could be important in natural systems. However, in contrast to previous theory we also found asymmetry weaker under mixing of communities with more complex trophic structure. PMID:24597234

  10. Resource niche overlap promotes stability of bacterial community metabolism in experimental microcosms.

    PubMed

    Hunting, Ellard R; Vijver, Martina G; van der Geest, Harm G; Mulder, Christian; Kraak, Michiel H S; Breure, Anton M; Admiraal, Wim

    2015-01-01

    Decomposition of organic matter is an important ecosystem process governed in part by bacteria. The process of decomposition is expected to benefit from interspecific bacterial interactions such as resource partitioning and facilitation. However, the relative importance of resource niche breadth (metabolic diversity) and resource niche overlap (functional redundancy) on decomposition and the temporal stability of ecosystem processes received little scientific attention. Therefore, this study aims to evaluate the effect of an increase in bacterial community resemblance on both decomposition and the stability of bacterial metabolism in aquatic sediments. To this end, we performed laboratory microcosm experiments in which we examined the influence of bacterial consortia differing in number and composition of species on bacterial activity (Electron Transport System Activity, ETSA), dissolved organic carbon production and wavelet transformed measurements of redox potential (Eh). Single substrate affinities of the individual bacterial species were determined in order to calculate the metabolic diversity of the microbial community. Results presented here indicate that bacterial activity and organic matter decomposition increase with widening of the resource niche breadth, and that metabolic stability increases with increasing overlap in bacterial resource niches, hinting that resource niche overlap can promote the stability of bacterial community metabolism. PMID:25759686

  11. Inhibitory Effect of Veterinary Antibiotics on Denitrification in Groundwater: A Microcosm Approach

    PubMed Central

    Kim, Kangjoo; Cho, Ju-Sik; Lee, Young Han; Joo, Young Kyoo; Lee, Sang Soo

    2014-01-01

    Veterinary antibiotics in groundwater may affect natural microbial denitrification process. A microcosm study was conducted to evaluate the influence of sulfamethazine and chlortetracycline at different concentrations (0, 0.01, 0.1, and 1.0 mg/L) on nitrate reduction in groundwater under denitrifying condition. Decrease in nitrate removal and nitrite production was observed with the antibiotics. Maximum inhibition of nitrate removal was observed after seven days of incubation with 0.01 mg/L sulfamethazine (17.0%) and 1.0 mg/L chlortetracycline (15.4%). The nitrite production was inhibited with 1.0 mg/L sulfamethazine to 82.0% and chlortetracycline to 31.1%. The initial/final nitrate concentrations indicated that 0.01 mg/L sulfamethazine and 1.0 mg/L chlortetracycline were most effective in inhibiting activity of denitrifying bacteria in groundwater. After 12 days of incubation, the sulfamethazine biodegradation was observed whereas chlortetracycline was persistent. Sulfamethazine and chlortetracycline in groundwater could inhibit the growth and capability of naturally occurring denitrifying bacteria, thereby threatening nitrate pollution in groundwater. PMID:24757442

  12. A Coexisting Fungal-Bacterial Community Stabilizes Soil Decomposition Activity in a Microcosm Experiment

    PubMed Central

    Ushio, Masayuki; Miki, Takeshi; Balser, Teri C.

    2013-01-01

    How diversity influences the stability of a community function is a major question in ecology. However, only limited empirical investigations of the diversity–stability relationship in soil microbial communities have been undertaken, despite the fundamental role of microbial communities in driving carbon and nutrient cycling in terrestrial ecosystems. In this study, we conducted a microcosm experiment to investigate the relationship between microbial diversity and stability of soil decomposition activities against changes in decomposition substrate quality by manipulating microbial community using selective biocides. We found that soil respiration rates and degradation enzyme activities by a coexisting fungal and bacterial community (a taxonomically diverse community) are more stable against changes in substrate quality (plant leaf materials) than those of a fungi-dominated or a bacteria-dominated community (less diverse community). Flexible changes in the microbial community composition and/or physiological state in the coexisting community against changes in substrate quality, as inferred by the soil lipid profile, may be the mechanism underlying this positive diversity–stability relationship. Our experiment demonstrated that the previously found positive diversity–stability relationship could also be valid in the soil microbial community. Our results also imply that the functional/taxonomic diversity and community ecology of soil microbes should be incorporated into the context of climate–ecosystem feedbacks. Changes in substrate quality, which could be induced by climate change, have impacts on decomposition process and carbon dioxide emission from soils, but such impacts may be attenuated by the functional diversity of soil microbial communities. PMID:24260368

  13. Responses of oxidation rate and microbial communities to methane in simulated landfill cover soil microcosms.

    PubMed

    He, Ruo; Ruan, Aidong; Jiang, Chenjing; Shen, Dong-Sheng

    2008-10-01

    CH4 oxidation capacities and microbial community structures developed in response to the presence of CH4 were investigated in two types of landfill cover soil microcosms, waste soil (fine material in stabilized waste) and clay soil. CH4 emission fluxes were lower in the waste soil cover over the course of the experiment. After exposure to CH4 flow for 120 days, the waste soil developed CH4 oxidation capacity from 0.53 to 11.25-13.48micromol CH4gd.w.(-1)h(-1), which was ten times higher than the clay soil. The topsoils of the two soil covers were observed dried and inhibited CH4 oxidation. The maximum CH4 oxidation rate occurred at the depth of 10-20cm in the waste soil cover (the middle layer), whereas it took place mainly at the depth of 20-30cm in the clay soil cover (the bottom layer). The amounts of the phospholipid fatty acid (PLFA) biomarks 16:1omega8c and 18:1omega8c for type I and II methanotrophs, respectively, showed that type I methanotrophic bacteria predominated in the clay soil, while the type II methanotrophic bacteria were abundant in the waste soil, and the highest population in the middle layer. The results also indicated that a greater active methanotrophic community was developed in the waste soil relative to the clay soil. PMID:18294841

  14. Frontiers of the food-energy-water trilemma: Sri Lanka as a microcosm of tradeoffs

    NASA Astrophysics Data System (ADS)

    Perrone, Debra; Hornberger, George

    2016-01-01

    Food, energy, and water are three critical resources for humanity. As climate variability, population growth, and lifestyle changes amplify the stress placed on each of the resources, the interrelationships among food, energy, and water systems become more pronounced. Political conflict, social and cultural norms, and spatial and temporal distribution of the resources add additional layers of complexity. It is in this context that the significance of understanding the impacts of water scarcity on the decisions around food and energy productions has emerged. Our work establishes tradeoff frontiers (TFs) as a method useful in illustrating the system-level tradeoffs between allocating water for food and water for energy. This paper illustrates how TFs can be used to (1) show how scarcity in water resources affects the tradeoffs between food and energy and (2) explore the political and social constraints that can move production away from what is feasible technically. We use Sri Lanka, a country where water resources are variable both in space and time and a country with relatively self-contained energy and agricultural sectors, as a microcosm of the food security, energy security, and water security trilemma. Nevertheless, our application of tradeoff frontiers is applicable widely to other systems.

  15. A microcosm model with discrete time: an approach and dynamical regimes

    NASA Astrophysics Data System (ADS)

    Evdokimov, E. V.; Shapovalov, A. V.

    A dynamical model of a closed 4-chain microcosm (with non-organic component, producers, consumers, and detritus) with discrete time is proposed. The model is based on a simple 3-chain integrable system of biological growth - eating away (non-organic component, producers, consumers) with continuous time. To construct the 4-chain model we integrate the 3-chain system and find the population numbers as explicit functions of time. By application of the time-shift operation for these functions we construct a map which describes the dynamics of the system with discrete time. This map is modified by introduction of additional terms responsible for producer and consumers death-rate, intra-species competition, and a relation describing detritus dynamics. Computer simulation of the map dynamics is performed. The model is shown to have stable regimes for correspondent values of the model parameters and initial data. The following types of dynamical regimes are also revealed: stable stationary states, decaying oscillations, limit cycles, and quasiharmonic oscillations. The detritus chain plays the role of a "friction" factor of the system oscillations. The work is supported by Russian Foundation for the Humanities.

  16. In Situ Determination of the Effects of Lead and Copper on Cyanobacterial Populations in Microcosms

    PubMed Central

    Burnat, Mireia; Diestra, Elia; Esteve, Isabel; Solé, Antonio

    2009-01-01

    Background Biomass has been studied as biomarker to evaluate the effect of heavy metals on microbial communities. Nevertheless, the most important methodological problem when working with natural and artificial microbial mats is the difficulty to evaluate changes produced on microorganism populations that are found in thicknesses of just a few mm depth. Methodology/Principal Findings Here, we applied for first time a recently published new method based on confocal laser scanning microscopy and image-program analysis to determine in situ the effect of Pb and Cu stress in cyanobacterial populations. Conclusions/Significance The results showed that both in the microcosm polluted by Cu and by Pb, a drastic reduction in total biomass for cyanobacterial and Microcoleus sp. (the dominant filamentous cyanobacterium in microbial mats) was detected within a week. According to the data presented in this report, this biomass inspection has a main advantage: besides total biomass, diversity, individual biomass of each population and their position can be analysed at microscale level. CLSM-IA could be a good method for analyzing changes in microbial biomass as a response to the addition of heavy metals and also to other kind of pollutants. PMID:19593432

  17. Temperature Responses of Ammonia-Oxidizing Prokaryotes in Freshwater Sediment Microcosms

    PubMed Central

    Yu, Zhongbo; Huang, Rui; Wu, Qinglong L.

    2014-01-01

    In order to investigate the effects of temperature on the abundances and community compositions of ammonia-oxidizing archaea (AOA) and bacteria (AOB), lake microcosms were constructed and incubated at 15°C, 25°C and 35°C for 40 days, respectively. Temperature exhibited different effects on the abundance and diversity of archaeal and bacterial amoA gene. The elevated temperature increased the abundance of archaeal amoA gene, whereas the abundance of bacterial amoA gene decreased. The highest diversity of bacterial amoA gene was found in the 25°C treatment sample. However, the 25°C treatment sample maintained the lowest diversity of archaeal amoA gene. Most of the archaeal amoA sequences obtained in this study affiliated with the Nitrosopumilus cluster. Two sequences obtained from the 15°C treatment samples were affiliated with the Nitrosotalea cluster. N. oligotropha lineage was the most dominant bacterial amoA gene group. Several sequences affiliated to Nitrosospira and undefined N. europaea/NC. mobilis like lineage were found in the pre-incubation and 25°C treatment groups. PMID:24959960

  18. Atrazine does not affect algal biomass or snail populations in microcosm communities at environmentally relevant concentrations.

    PubMed

    Baxter, Leilan R; Moore, Dana L; Sibley, Paul K; Solomon, Keith R; Hanson, Mark L

    2011-07-01

    The herbicide atrazine is a photosynthetic inhibitor used around the world in agricultural applications. Contamination of surface waters adjacent to treated areas can directly reduce growth of nontarget aquatic autotrophs, but the severity of impacts is highly dependent on species sensitivity and exposure concentration. Secondary effects resulting from macrophyte or phytoplankton decline may include an expansion of the more tolerant periphyton community. Recently, this shift in the autotrophic community has been proposed as a mechanism for increased rates of parasite infections in amphibians via augmented populations of aquatic snails which act as intermediate hosts to larval trematodes. To further clarify this relationship, an outdoor microcosm study was conducted to examine the effects of atrazine on primary production and snail populations over a range of environmentally relevant concentrations. In July 2009, 15 experimental ponds were treated to achieve initial concentrations of 0, 1, 10, 30, and 100 µg/L atrazine. Over a period of 73 d, measures were taken of macrophyte, phytoplankton, and periphyton biomass, growth, and fecundity of caged snails (Physella spp. and Stagnicola elodes) and free-living snails (Physella spp.). Except for declines in macrophyte biomass at the highest treatment level, no consistent relationships were found between atrazine concentration and any measured parameter. Comparison of these results with previous findings highlights the variability of responses to atrazine exposure between similarly constructed freshwater communities, even at concentrations up to 20 times higher than sustained environmental levels. PMID:21567448

  19. Diffusional losses of amended anaerobic electron acceptors in sediment field microcosms.

    PubMed

    Mittal, Menka; Rockne, Karl J

    2010-08-01

    Hudson River sediment microcosms from Piles Creek (PC), Piermont Marsh (PM), and Iona Island (II) were amended with approximately 100mM nitrate or sulfate to stimulate anaerobic bioremediation. Nitrate and sulfate decreased over two years of field incubation and the fraction of these losses due to diffusion to the water column was predicted using Fick's law. Apparent diffusion (D(app)) values of 1-4x10(-10)m(2)s(-1) predicted the majority of loss/gain from/to the sediments by 700 d, but not at all times. Effective diffusion (D(eff)) values predicted by the porosity function (D(eff)=D(mol)epsilon(4/3)) were larger than those observed in the field, and field data indicates a cube power relationship: D(eff)=D(mol)epsilon(3). D(app) greatly increased in surficial layers at PM and PC in year two, suggesting that bioadvection caused by bioturbating organisms had occurred. The effects of bioturbation on transport to/from the sediments are modeled, and results can be applied to various sediment treatment scenarios such as capping. PMID:20399475

  20. Temporal succession in carbon incorporation from macromolecules by particle-attached bacteria in marine microcosms.

    PubMed

    Mayali, Xavier; Stewart, Benjamin; Mabery, Shalini; Weber, Peter K

    2016-02-01

    We investigated bacterial carbon assimilation from stable isotope-labelled macromolecular substrates (proteins; lipids; and two types of polysaccharides, starch and cellobiose) while attached to killed diatom detrital particles during laboratory microcosms incubated for 17 days. Using Chip-SIP (secondary ion mass spectrometry analysis of RNA microarrays), we identified generalist operational taxonomic units (OTUs) from the Gammaproteobacteria, belonging to the genera Colwellia, Glaciecola, Pseudoalteromonas and Rheinheimera, and from the Bacteroidetes, genera Owenweeksia and Maribacter, that incorporated the four tested substrates throughout the incubation period. Many of these OTUs exhibited the highest isotope incorporation relative to the others, indicating that they were likely the most active. Additional OTUs from the Gammaproteobacteria, Bacteroidetes and Alphaproteobacteria exhibited generally (but not always) lower activity and did not incorporate all tested substrates at all times, showing species succession in organic carbon incorporation. We also found evidence to suggest that both generalist and specialist OTUs changed their relative substrate incorporation over time, presumably in response to changing substrate availability as the particles aged. This pattern was demonstrated by temporal succession from relatively higher starch incorporation early in the incubations, eventually switching to higher cellobiose incorporation after 2 weeks. PMID:26525158

  1. Diverse Reductive Dehalogenases Are Associated with Clostridiales-Enriched Microcosms Dechlorinating 1,2-Dichloroethane

    PubMed Central

    Merlino, Giuseppe; Balloi, Annalisa; Marzorati, Massimo; Mapelli, Francesca; Rizzi, Aurora; Lavazza, Davide; de Ferra, Francesca; Carpani, Giovanna; Daffonchio, Daniele

    2015-01-01

    The achievement of successful biostimulation of active microbiomes for the cleanup of a polluted site is strictly dependent on the knowledge of the key microorganisms equipped with the relevant catabolic genes responsible for the degradation process. In this work, we present the characterization of the bacterial community developed in anaerobic microcosms after biostimulation with the electron donor lactate of groundwater polluted with 1,2-dichloroethane (1,2-DCA). Through a multilevel analysis, we have assessed (i) the structural analysis of the bacterial community; (ii) the identification of putative dehalorespiring bacteria; (iii) the characterization of functional genes encoding for putative 1,2-DCA reductive dehalogenases (RDs). Following the biostimulation treatment, the structure of the bacterial community underwent a notable change of the main phylotypes, with the enrichment of representatives of the order Clostridiales. Through PCR targeting conserved regions within known RD genes, four novel variants of RDs previously associated with the reductive dechlorination of 1,2-DCA were identified in the metagenome of the Clostridiales-dominated bacterial community. PMID:26273600

  2. Temperature responses of ammonia-oxidizing prokaryotes in freshwater sediment microcosms.

    PubMed

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

    2014-01-01

    In order to investigate the effects of temperature on the abundances and community compositions of ammonia-oxidizing archaea (AOA) and bacteria (AOB), lake microcosms were constructed and incubated at 15°C, 25°C and 35°C for 40 days, respectively. Temperature exhibited different effects on the abundance and diversity of archaeal and bacterial amoA gene. The elevated temperature increased the abundance of archaeal amoA gene, whereas the abundance of bacterial amoA gene decreased. The highest diversity of bacterial amoA gene was found in the 25°C treatment sample. However, the 25°C treatment sample maintained the lowest diversity of archaeal amoA gene. Most of the archaeal amoA sequences obtained in this study affiliated with the Nitrosopumilus cluster. Two sequences obtained from the 15°C treatment samples were affiliated with the Nitrosotalea cluster. N. oligotropha lineage was the most dominant bacterial amoA gene group. Several sequences affiliated to Nitrosospira and undefined N. europaea/NC. mobilis like lineage were found in the pre-incubation and 25°C treatment groups. PMID:24959960

  3. Herbicide mitigation in microcosms simulating stormwater basins subject to polluted water inputs.

    PubMed

    Bois, P; Huguenot, D; Jézéquel, K; Lollier, M; Cornu, J Y; Lebeau, T

    2013-03-01

    Non-point source pollution as a result of wine-growing activity is of high concern. Stormwater basins (SWB) found downstream of vineyard watersheds could show a potential for the mitigation of runoff water containing herbicides. In this study, mitigation of vinery-used herbicides was studied in microcosms with a very similar functioning to that recorded in SWB. Mitigation efficiency of glyphosate, diuron and 3,4-dichloroaniline (3,4-DCA) was investigated by taking into account hydraulic flow rate, mitigation duration, bioaugmentation and plant addition. Mitigation efficiency measured in water ranged from 63.0% for diuron to 84.2% for 3,4-DCA and to 99.8% for glyphosate. Water-storage duration in the SWB and time between water supplies were shown to be the most influential factors on the mitigation efficiency. Six hours water-storage duration allowed an efficient sorption of herbicides and their degradation by indigenous microorganisms in 5 weeks. Neither bioaugmentation nor plant addition had a significant effect on herbicide mitigation. Our results show that this type of SWB are potentially relevant for the mitigation of these herbicides stemming from wine-growing activity, providing a long enough hydraulic retention time. PMID:23246667

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

    PubMed

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

    2016-05-01

    Pentolite is a mixture (1:1) of 2,4,6-trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN), and little is known about its fate in the environment. This study was aimed to determine the dissipation of pentolite in soils under laboratory conditions. Microcosm experiments conducted with two soils demonstrated that dissipation rate of PETN was significantly slower than that of TNT. Interestingly, the dissipation of PETN was enhanced by the presence of TNT, while PETN did not enhanced the dissipation of TNT. Pentolite dissipation rate was significantly faster under biostimulation treatment (addition of carbon source) in soil from the artificial wetland, while no such stimulation was observed in soil from detonation field. In addition, the dissipation rate of TNT and PETN in soil from artificial wetland under biostimulation was significantly faster than the equivalent abiotic control, although it seems that non-biological processes might also be important for the dissipation of TNT and PETN. Transformation of PETN was also slower during establishment of enrichment culture using pentolite as the sole nitrogen source. In addition, transformation of these explosives was gradually reduced and practically stopped after the forth cultures transfer (80 days). DGGE analysis of bacterial communities from these cultures indicates that all consortia were dominated by bacteria from the order Burkholderiales and Rhodanobacter. In conclusion, our results suggest that PETN might be more persistent than TNT. PMID:26832872

  5. Study on the effects of near-future ocean acidification on marine yeasts: a microcosm approach

    NASA Astrophysics Data System (ADS)

    Krause, Evamaria; Wichels, Antje; Erler, René; Gerdts, Gunnar

    2013-12-01

    Marine yeasts play an important role in biodegradation and nutrient cycling and are often associated with marine flora and fauna. They show maximum growth at pH levels lower than present-day seawater pH. Thus, contrary to many other marine organisms, they may actually profit from ocean acidification. Hence, we conducted a microcosm study, incubating natural seawater from the North Sea at present-day pH (8.10) and two near-future pH levels (7.81 and 7.67). Yeasts were isolated from the initial seawater sample and after 2 and 4 weeks of incubation. Isolates were classified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and representative isolates were identified by partial sequencing of the large subunit rRNA gene. From the initial seawater sample, we predominantly isolated a yeast-like filamentous fungus related to Aureobasidium pullulans, Cryptococcus sp., Candida sake, and various cold-adapted yeasts. After incubation, we found more different yeast species at near-future pH levels than at present-day pH. Yeasts reacting to low pH were related to Leucosporidium scottii, Rhodotorula mucilaginosa, Cryptococcus sp., and Debaryomyces hansenii. Our results suggest that these yeasts will benefit from seawater pH reductions and give a first indication that the importance of yeasts will increase in a more acidic ocean.

  6. Microcosm assays and Taguchi experimental design for treatment of oil sludge containing high concentration of hydrocarbons.

    PubMed

    Castorena-Cortés, G; Roldán-Carrillo, T; Zapata-Peñasco, I; Reyes-Avila, J; Quej-Aké, L; Marín-Cruz, J; Olguín-Lora, P

    2009-12-01

    Microcosm assays and Taguchi experimental design was used to assess the biodegradation of an oil sludge produced by a gas processing unit. The study showed that the biodegradation of the sludge sample is feasible despite the high level of pollutants and complexity involved in the sludge. The physicochemical and microbiological characterization of the sludge revealed a high concentration of hydrocarbons (334,766+/-7001 mg kg(-1) dry matter, d.m.) containing a variety of compounds between 6 and 73 carbon atoms in their structure, whereas the concentration of Fe was 60,000 mg kg(-1) d.m. and 26,800 mg kg(-1) d.m. of sulfide. A Taguchi L(9) experimental design comprising 4 variables and 3 levels moisture, nitrogen source, surfactant concentration and oxidant agent was performed, proving that moisture and nitrogen source are the major variables that affect CO(2) production and total petroleum hydrocarbons (TPH) degradation. The best experimental treatment yielded a TPH removal of 56,092 mg kg(-1) d.m. The treatment was carried out under the following conditions: 70% moisture, no oxidant agent, 0.5% of surfactant and NH(4)Cl as nitrogen source. PMID:19635663

  7. Fate of metal resistance genes in arable soil after manure application in a microcosm study.

    PubMed

    Xiong, Wenguang; Zeng, Zhenling; Zhang, Yiming; Ding, Xueyao; Sun, Yongxue

    2015-03-01

    Manure application contributes to the spread and persistence of metal resistance genes (MRGs) in the environment. We investigated the fate of copper (Cu) and zinc (Zn) resistance genes (pcoA, pcoD and zntA) in arable soil after Cu/Zn-containing manure application. Manure with or without addition of metals (Cu/Zn) was added in a soil microcosm over 2 months. Soil samples were collected for analysis on day 0, 30 and 60. The abundances of all MRGs (pcoA, pcoD and zntA) in manure group were significantly higher than those in untreated soil and manure+metals groups. All MRGs dissipated 1.2-1.3 times faster in manure group (from -90 ± 8% to -93 ± 7%) than those in manure+metals group (from -68 ± 8% to -78 ± 5%). The results indicated that manure from healthy pigs contributed to the occurrence of metals (Cu/Zn) and MRGs (pcoA, pcoD and zntA) in arable soil. The significant effects of manure application on the accumulation of pcoA, pcoD and zntA lasted for 1-2 months. Cu/Zn can slow down the dissipation of pcoA, pcoD and zntA after manure application. This is the first report to investigate the fate of MRGs in soil after manure application. PMID:25483373

  8. Fate of Viable but Non-culturable Listeria monocytogenes in Pig Manure Microcosms

    PubMed Central

    Desneux, Jérémy; Biscuit, Audrey; Picard, Sylvie; Pourcher, Anne-Marie

    2016-01-01

    The fate of two strains of Listeria monocytogenes and their ability to become viable but non-culturable (VBNC) was investigated in microcosms containing piggery effluents (two raw manures and two biologically treated manures) stored for 2 months at 8 and 20°C. Levels of L. monocytogenes were estimated using the culture method, qPCR, and propidium monoazide treatment combined with qPCR (qPCRPMA). The chemical composition and the microbial community structure of the manures were also analyzed. The strains showed similar decline rates and persisted up to 63 days. At day zero, the percentage of VBNC cells among viable cells was higher in raw manures (81.5–94.8%) than in treated manures (67.8–79.2%). The changes in their proportion over time depended on the temperature and on the type of effluent: the biggest increase was observed in treated manures at 20°C and the smallest increase in raw manures at 8°C. The chemical parameters had no influence on the behavior of the strains, but decrease of the persistence of viable cells was associated with an increase in the microbial richness of the manures. This study demonstrated that storing manure altered the culturability of L. monocytogenes, which rapidly entered the VBNC state, and underlines the importance of including VBNC cells when estimating the persistence of the pathogens in farm effluents. PMID:26973623

  9. The effects of plant diversity on nitrous oxide emissions in hydroponic microcosms

    NASA Astrophysics Data System (ADS)

    Sun, Hongying; Zhang, Chongbang; Song, Changchun; Chang, Scott X.; Gu, Baojing; Chen, Zhengxin; Peng, Changhui; Chang, Jie; Ge, Ying

    2013-10-01

    Previous studies have shown that plant diversity can improve the wastewater purification efficiency of constructed wetlands (CWs), but its effect on the nitrous oxide (N2O) emission in CWs has been unknown. To investigate the effect of plant diversity on the N2O emission, we established four plant species richness levels (each level containing 1, 2, 3 and 4 species, respectively) by using 96 hydroponic microcosms. Results showed that plant species richness enhanced the N2O emission, ranging from 27.1 to 115.4 μg N2O m-2 d-1, and improved nitrate removal (P < 0.001). The presence of Phalaris arundinacea within a given plant community increased the N2O emission (P < 0.001). The presence of Rumex japonicas had no influence on the N2O emissions (P > 0.05), but improved nitrogen removal (P < 0.001). Hence, our study highlights the importance of both plant species richness and species identity in mediating the N2O emission and nitrogen removal in CWs.

  10. Changes in Arctic and Antarctic Sea Ice as a Microcosm of Global Climate Change

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.

    2014-01-01

    Polar sea ice is a key element of the climate system and has now been monitored through satellite observations for over three and a half decades. The satellite observations reveal considerable information about polar ice and its changes since the late 1970s, including a prominent downward trend in Arctic sea ice coverage and a much lesser upward trend in Antarctic sea ice coverage, illustrative of the important fact that climate change entails spatial contrasts. The decreasing ice coverage in the Arctic corresponds well with contemporaneous Arctic warming and exhibits particularly large decreases in the summers of 2007 and 2012, influenced by both preconditioning and atmospheric conditions. The increasing ice coverage in the Antarctic is not as readily explained, but spatial differences in the Antarctic trends suggest a possible connection with atmospheric circulation changes that have perhaps been influenced by the Antarctic ozone hole. The changes in the polar ice covers and the issues surrounding those changes have many commonalities with broader climate changes and their surrounding issues, allowing the sea ice changes to be viewed in some important ways as a microcosm of global climate change.

  11. Integrating Mass Spectrometry of Intact Protein Complexes into Structural Proteomics

    PubMed Central

    Hyung, Suk-Joon; Ruotolo, Brandon T.

    2013-01-01

    Summary Mass spectrometry analysis of intact protein complexes has emerged as an established technology for assessing the composition and connectivity within dynamic, heterogeneous multiprotein complexes at low concentrations and in the context of mixtures. As this technology continues to move forward, one of the main challenges is to integrate the information content of such intact protein complex measurements with other mass spectrometry approaches in structural biology. Methods such as H/D exchange, oxidative foot-printing, chemical cross-linking, affinity purification, and ion mobility separation add complementary information that allows access to every level of protein structure and organization. Here, we survey the structural information that can be retrieved by such experiments, demonstrate the applicability of integrative mass spectrometry approaches in structural proteomics, and look to the future to explore upcoming innovations in this rapidly-advancing area. PMID:22611037

  12. Radioactive satellites - Intact reentry and breakup by debris impact

    NASA Technical Reports Server (NTRS)

    Anz-Meador, P. D.; Potter, A. E., Jr.

    1991-01-01

    There is a substantial mass of radioactive material in nuclear reactors or radioisotope thermal generators (RTGs) in orbit about the earth. This paper examines the reentry of intact nuclear fuel cores and RTGs and the fragmentation and subsequent radioactive debris cloud deposition and evolution resulting from the impact of orbital debris upon an orbiting reactor, fuel core, or RTG. To assess the intact reentry, decay rates and a predicted decay date using historical and projected orbital decay data, are estimated. The current NASA debris environment model is utilized to estimate impact rates and debris cloud evolution of a fragmentation event. Results of these analyses are compared and concepts are tendered which would tend to minimize the radiological debris hazard to personnel and structures both on the earth's surface and in low earth orbit.

  13. An integrated workflow for characterizing intact phosphoproteins from complex mixtures

    SciTech Connect

    Wu, Si; Yang, Feng; Zhao, Rui; Tolic, Nikola; Robinson, Errol W.; Camp, David G.; Smith, Richard D.; Pasa-Tolic, Ljiljana

    2009-05-08

    The phosphorylation of any site on a given protein can affect its activity, degradation rate, ability to dock with other proteins or bind divalent cations, and/or its localization. These effects can operate within the same protein; in fact, multisite phosphorylation is a key mechanism for achieving signal integration in cells. Hence, knowing the overall phosphorylation signature of a protein is essential for understanding the "state" of a cell. However, current technologies to monitor the phosphorylation status of proteins are inefficient at determining the relative stoichiometries of phosphorylation at multiple sites. Here we report a new capability for comprehensive liquid chromatography-mass spectrometry (LC-MS) analysis of intact phosphoproteins. The technology platform built upon integrated bottom-up and top-down approach that is facilitated by intact protein reversed-phase (RP)LC concurrently coupled with Fourier transform ion cyclotron resonance (FTICR) MS and fraction collection.

  14. Structural determination of intact proteins using mass spectrometry

    DOEpatents

    Kruppa, Gary; Schoeniger, Joseph S.; Young, Malin M.

    2008-05-06

    The present invention relates to novel methods of determining the sequence and structure of proteins. Specifically, the present invention allows for the analysis of intact proteins within a mass spectrometer. Therefore, preparatory separations need not be performed prior to introducing a protein sample into the mass spectrometer. Also disclosed herein are new instrumental developments for enhancing the signal from the desired modified proteins, methods for producing controlled protein fragments in the mass spectrometer, eliminating complex microseparations, and protein preparatory chemical steps necessary for cross-linking based protein structure determination.Additionally, the preferred method of the present invention involves the determination of protein structures utilizing a top-down analysis of protein structures to search for covalent modifications. In the preferred method, intact proteins are ionized and fragmented within the mass spectrometer.

  15. On the sensitivity of intact cells to perturbation by ethanol

    SciTech Connect

    Hitzemann, R.; Whitaker-Azmitia, P. ); Dains, K.; Lin, J. )

    1989-01-01

    A comparison was made of ethanol's effects on the order of plasma membranes in intact cells and some isolated membrane preparations. Order was assessed by steady-state fluorescence polarization techniques using the non-permeant probe, TMA-DPH. The data show that two cultured cells, rat neonatal astroglial and N2A neuroblastoma, were sensitive to significant ethanol-induced disordering within the anesthetically relevant range. Human erythrocytes, cultured fibroblasts and homogenized astroglial cells required higher ethanol concentrations to produce a similar effect. Intact erythrocytes were approximately twice as sensitive as erythrocyte ghost membranes to ethanol induced perturbation. The neonatal glial and N2A cells were approximately five times more sensitive than synaptic membranes to ethanol effects. DMPC and DMPC + cholesterol liposomes and myelin membranes were insensitive to ethanol's effects. The incorporation of 10 mole % ganglioside GM{sub 1} sensitized the liposomes to ethanol-induced perturbation.

  16. Chlorophyll Determination in Intact Tissues Using N,N-Dimethylformamide

    PubMed Central

    Moran, Rami; Porath, Dan

    1980-01-01

    Photosynthetic pigments from etiolated cucumber (Cucumis sativus var. Beit Alpha improved, Hazera Co., Gedera) cotyledons were extracted by direct immersion of the intact cotyledons into the solvent N,N-dimethylformamide (DMF). The solvent is especially efficient when pigment concentration is low; time and tools are saved and the loss of pigment that usually occurs in more complicated extraction procedures is prevented. The specific absorption coefficient of chlorophyll a in DMF was also determined. PMID:16661217

  17. Aquatic risk assessment of a novel strobilurin fungicide: A microcosm study compared with the species sensitivity distribution approach.

    PubMed

    Chen, Lang; Song, Yufang; Tang, Baohua; Song, Xueying; Yang, Hairong; Li, Baiyu; Zhao, Yu; Huang, Chengtian; Han, Xue; Wang, Shaoye; Li, Zhaoli

    2015-10-01

    The ecotoxicological effects of pyraoxystrobin, a novel strobilurin fungicide, were studied using outdoor freshwater microcosms and the species sensitivity distribution approach. The microcosms were treated with pyraoxystrobin at concentrations of 0, 1.0, 3.0, 10, 30 and 100µg/L. Species sensitivity distribution (SSD) curves were constructed by means of acute toxicity data using the BurrliOZ model for fourteen representatives of sensitive invertebrates, algae and fish and eleven taxa of invertebrates and algae, respectively. The responses of zooplankton, phytoplankton and physical and chemical endpoints in microcosms were studied. Zooplankton, especially Sinodiaptomus sarsi was the most sensitive to pyraoxystrobin exposure in the microcosms. Short-term toxic effects (<8 weeks) on zooplankton occurred in 1µg/L treatment group. The duration of toxic effects on S. sarsi could not be evaluated within the initial 56 days. Significant long-term toxic effects were observed at 10, 30 and 100µg/L (>281 days) for S. sarsi and the zooplankton community. Based on the results obtained from the organisms in the microcosm system, 1µg/L was recommended as the NOEAEC (no observed ecologically adverse effect concentration). Also, 0.33µg/L was derived as the Regulatory Acceptable Concentration based on the ecological recovery option (ERO-RAC) of pyraoxystrobin. For all fourteen tested species, the median HC5 (hazardous concentration affecting 5% of species) was 0.86µg/L, and the lower limit HC5 (LL-HC5) was 0.39µg/L. For the eleven taxa of invertebrates and algae tested, the median HC5 was 1.1µg/L, and the LL-HC5 was 0.26µg/L. The present study positively contributes to the suggestion of adequately using acute L(E)C50-based HC5/ LL-HC5 for deriving protective concentrations for strobilurin fungicides, and it should be valuable for full comprehension of the potential toxicity of pyraoxystrobin in aquatic ecosystems. PMID:26122735

  18. Effects of sediment-spiked lufenuron on benthic macroinvertebrates in outdoor microcosms and single-species toxicity tests.

    PubMed

    Brock, T C M; Bas, D A; Belgers, J D M; Bibbe, L; Boerwinkel, M-C; Crum, S J H; Diepens, N J; Kraak, M H S; Vonk, J A; Roessink, I

    2016-08-01

    Sediment ecotoxicity studies were conducted with lufenuron to (i) complement the results of a water-spiked mesocosm experiment with this lipophilic benzoylurea insecticide, (ii) to explore the predictive value of laboratory single-species tests for population and community-level responses of benthic macroinvertebrates, and (iii) to calibrate the tier-1 effect assessment procedure for sediment organisms. For this purpose the concentration-response relationships for macroinvertebrates between sediment-spiked microcosms and those of 28-d sediment-spiked single-species toxicity tests with Chironomus riparius, Hyalella azteca and Lumbriculus variegatus were compared. Lufenuron persisted in the sediment of the microcosms. On average, 87.7% of the initial lufenuron concentration could still be detected in the sediment after 12 weeks. Overall, benthic insects and crustaceans showed treatment-related declines and oligochaetes treatment-related increases. The lowest population-level NOEC in the microcosms was 0.79μg lufenuron/g organic carbon in dry sediment (μg a.s./g OC) for Tanytarsini, Chironomini and Dero sp. Multivariate analysis of the responses of benthic macroinvertebrates revealed a community-level NOEC of 0.79μg a.s./g OC. The treatment-related responses observed in the microcosms are in accordance with the results of the 28-d laboratory toxicity tests. These tests showed that the insect C. riparius and the crustacean H. azteca were approximately two orders of magnitude more sensitive than the oligochaete L. variegatus. In our laboratory tests, using field-collected sediment, the lowest 28-d EC10 (0.49μg a.s./g OC) was observed for C. riparius (endpoint survival), while for the standard OECD test with this species, using artificial sediment, a NOEC of 2.35μg a.s./g OC (endpoint emergence) is reported. In this particular case, the sediment tier-1 effect assessment using the chronic EC10 (field-collected sediment) or chronic NOEC (artificial sediment) of C

  19. Intracellular Delivery of Proteins via Fusion Peptides in Intact Plants

    PubMed Central

    Ng, Kiaw Kiaw; Motoda, Yoko; Watanabe, Satoru; Sofiman Othman, Ahmad; Kigawa, Takanori; Kodama, Yutaka; Numata, Keiji

    2016-01-01

    In current plant biotechnology, the introduction of exogenous DNA encoding desired traits is the most common approach used to modify plants. However, general plant transformation methods can cause random integration of exogenous DNA into the plant genome. To avoid these events, alternative methods, such as a direct protein delivery system, are needed to modify the plant. Although there have been reports of the delivery of proteins into cultured plant cells, there are currently no methods for the direct delivery of proteins into intact plants, owing to their hierarchical structures. Here, we demonstrate the efficient fusion-peptide-based delivery of proteins into intact Arabidopsis thaliana. Bovine serum albumin (BSA, 66 kDa) was selected as a model protein to optimize conditions for delivery into the cytosol. The general applicability of our method to large protein cargo was also demonstrated by the delivery of alcohol dehydrogenase (ADH, 150 kDa) into the cytosol. The compatibility of the fusion peptide system with the delivery of proteins to specific cellular organelles was also demonstrated using the fluorescent protein Citrine (27 kDa) conjugated to either a nuclear localization signal (NLS) or a peroxisomal targeting signal (PTS). In conclusion, our designed fusion peptide system can deliver proteins with a wide range of molecular weights (27 to 150 kDa) into the cells of intact A. thaliana without interfering with the organelle-targeting peptide conjugated to the protein. We expect that this efficient protein delivery system will be a powerful tool in plant biotechnology. PMID:27100681

  20. Physical and Biological Interactions of Intact Watersheds: Are they relevant?

    NASA Astrophysics Data System (ADS)

    Bryant, M.

    2005-05-01

    Intact watersheds are rare or absent throughout most of the northern hemisphere. Southeast Alaska is an exception with many forested watersheds that either have not been or are lightly disturbed by human activity. The Kadashan River, a short (less than 20 km) river in an old growth watershed on Chichagof Island is one example of an intact watershed. Natural processes from the headwaters to the ocean interact to create a salmon rich environment. Steep headwater streams are sources for sediment recruitment, nutrients (organic material and invertebrates), and large wood. Large riparian trees entering the stream provide long term storage of sediment, create pools, and link the main stream to off-channel habitats. A natural discharge regime that floods a complex riparian zone with abundant beaver ponds is a key process that maintains this complex system. Examples of these processes and salmonid populations in the Kadashan River illustrate how they interact to support one of the more productive watersheds in southeast Alaska. Understanding and quantifying processes in intact watersheds provide an opportunity to test major river paradigms and provide reference points for watershed restoration projects elsewhere.

  1. Carboxylated and intact osteocalcin predict adiponectin concentration in hemodialyzed patients.

    PubMed

    Kuźniewski, Marek; Fedak, Danuta; Dumnicka, Paulina; Kapusta, Maria; Stępień, Ewa; Chowaniec, Eve; Krzanowska, Katarzyna; Krzanowski, Marcin; Chmiel, Grzegorz; Solnica, Bogdan; Sułowicz, Władysław

    2016-01-01

    Purpose Disrupted bone metabolism in patients with chronic kidney disease (CKD) is associated with elevated concentrations of biochemical bone markers. Recently, animal studies show the role of osteocalcin in energy metabolism, which is partially confirmed in humans. The aim of our study was to evaluate the relationships between serum concentrations of bone markers and indices of energy metabolism in CKD patients on maintenance hemodialysis; in particular, the relationship between various forms of osteocalcin and adiponectin. Patients and methods The cross-sectional study included 155 hemodialyzed stage 5 CKD patients. Serum concentrations of glucose, insulin, adiponectin, bone alkaline phosphatase (bALP), tartrate resistant acid phosphatase (TRAP), carboxylated (cOC), undercarboxylated (ucOC), and intact osteocalcin (OC) were determined. Results In total cohort, bALP, TRAP, cOC, and ucOC negatively correlated with BMI. All analyzed bone markers positively correlated with adiponectin in total cohort and in men. In multiple linear regression analysis including all patients, log(cOC) and log(intact OC) were the only bone markers that predicted log(adiponectin) (beta = 0.22; p = 0.016 and beta = 0.26; p = 0.010) independently of sex, dialysis vintage, CRP, insulin, iPTH concentrations, BMI, and age. Conclusions Our data confirm the positive association between cOC, intact OC, and adiponectin concentrations in CKD patients on maintenance hemodialysis. PMID:26822199

  2. Vehicle influence on permeation through intact and compromised skin.

    PubMed

    Gujjar, Meera; Banga, Ajay K

    2014-09-10

    The purpose of this study was to compare the transdermal permeation of a model compound, diclofenac diethylamine, from a hydrophilic and lipophilic vehicle across in vitro models simulating compromised skin. Mineral oil served as a lipophilic vehicle while 10mM phosphate buffered saline served as a hydrophilic vehicle. Compromised skin was simulated by tape stripping, delipidization, or microneedle application and compared with intact skin as a control. Transepidermal water loss was measured to assess barrier function. Skin compromised with tape stripping and delipidization significantly (p<0.05) increased permeation of diclofenac diethylamine compared to intact and microneedle treated skin with phosphate buffered saline vehicle. A similar trend in permeation was observed with mineral oil as the vehicle. For both vehicles, permeation across skin increased in the same order and correlated with degree of barrier impairment as indicated by transepidermal water loss values: intact

  3. A chamber for applying pressure to roots of intact plants.

    PubMed

    Gee, G W

    1973-11-01

    A chamber was designed to apply up to 20 bars pressure to roots of intact plants. The unique features of this chamber are a split top arrangement to permit enclosing roots of intact plants within the chamber, a circulation coil to control temperature of rooting media, and a valve arrangement to permit changing solution without disturbing the plant. Changes in transpiration in response to changes in the pressure applied to roots of intact pepper plants illustrate one use of the equipment. Well watered plants at low light (0.05 langley/min) were observed to exude water from the leaf margins when 5 bars pressure was applied to the roots. When roots were cut off, a 1 bar pressure caused exudation. Plants with cooled roots or plants in dry soil did not exude water when as much as 6 bars pressure was applied. Transient response of transpiration rates to sudden application and release of pressure was observed in pepper and bean plants but not in rhododendron. The magnitude of this transient response was highly dependent upon light intensity and CO(2) concentration in the aerial environment. PMID:16658586

  4. Modified madigan prostatectomy: a procedure preserved prostatic urethra intact.

    PubMed

    Lu, Jun; Ye, Zhangqun; Hu, Weilie

    2005-01-01

    A total of 92 patients with benign prostatic hyperplasia (BPH) were subjected to modified Madigan prostatectomy (MPC) for a much satisfactory effect in open prostatectomy surgery. Exposing anterior prostatic urethra near the bladder neck and conjunct cystotomy modified the MPC procedure. This modified procedure preserved prostatic urethra intact and could also deal with intracystic lesions at the same time. The intact of prostatic urethra was kept completely or largely in 86 cases. The amount of blood loss during modified procedure was less. The mean operative time was 105 min. Seventy patients had been followed up for 3-24 months. The postoperative average Qmax was 19. 2 ml/s. The cystourethrography revealed that the urethra and bladder neck were intact in 10 patients postoperatively. Furthermore, the prostatic urethra was obviously wider after modified MPC. The modified MPC can reduce the occurrence of urethra injury and enlarge the MPC indications. The modified technique is easy to perform with less complications and much satisfactory clinical result. PMID:16201285

  5. Microcosm wetlands for wastewater treatment with different hydraulic loading rates and macrophytes.

    PubMed

    Jing, Shuh-Ren; Lin, Ying-Feng; Wang, Tze-Wen; Lee, Der-Yuan

    2002-01-01

    Constructed wetlands (CW) usually require large land areas for treating wastewater. This study evaluated the feasibility of applying CW with less land requirement by operating a group of microcosm wetlands at a hydraulic retention time (HRT) of less than 4 d in southern Taiwan. An artificial wastewater, simulating municipal wastewater containing 200 mg L(-1) of chemical oxygen demand (COD), 20 mg L(-1) of NH4+-N (AN), and 20 mg L(-1) of PO4(3-)-P (OP), was the inflow source. Three emergent plants [reed, Phragmites australis (Cav.) Trin. ex Steud.; water primrose, Ludwigia octovalvis (Jacq.) P.H. Raven; and dayflower, Commelina communis L.] and two floating plants [water spinach, Ipomoea aquatica Forssk.; and water lettuce, Pistia stratiotes L.] plants were tested. The planted systems showed more nutrient removal than unplanted systems; however, the type of macrophytes in CW did not make a major difference in treatment. At the HRTs of 2 to 4 d, the planted system maintained greater than 72,80, and 46% removal for COD, AN, and OP, respectively. For AN and OP removal, the highest efficiencies occurred at the HRT of 3 d, whereas maximum removal rates for AN and OP occurred at the HRT of 2 d. Both removal rates and efficiencies were reduced drastically at the HRT of 1 d. Removals of COD, OP, and AN followed first-order reactions within the HRTs of 1 to 4 d. The efficient removals of these constituents obtained with HRT between 2 and 4 d indicated the possibility of using a CW system for wastewater treatment with less land requirement. PMID:11931463

  6. Examination of a Smallest CELSS (Microcosm) Through an Individual- Based-Model Simulation

    NASA Astrophysics Data System (ADS)

    Ishikawa, Y.; Sugiura, K.

    Research of the effect of space environment on an ecosystem consisting of plants and animals is essential when they are to be positively used in space. Although there have been experiments on various organisms under space environment in the past, they mainly studied the effect of space environment on an individual organism or a single species. Microcosm is drawing attention as an experimental material of an ecosystem consisting of multiple species. The object in this research is to understand the nature of this network system called ecosystem. Thus, a mixed microorganism culturing system consisting of three types of microorganisms (chlorella, bacteria, and rotifer) which form a minimum food chain system as a closed ecosystem was taken for the subject, on which the universal characteristics of ecosystems is searched. From the results of experiments under earth environment, formation of colonies, which is an ecological structure, has been observed at its mature stage. Therefore, formation of colonies in simulation models is important. For example, the Lotka- Volterra model forms a system of the differential equations expressing predator and prey relationship and many numerical calculations have been conducted to various ecosystems based on expanded L-V models. Conventionally, these top-down methods have been used. However, since this method only describes the average concentration of organisms that are distributed uniformly throughout the system and cannot express the spatial structure of the system, it was difficult to express the ecosystem structures like colonies and substance density distribution. In actual ecosystems, there is heterogeneity in the number of individuals and in substance density, and this is thought to have great significance in ecosystems. Consequently, an Individual-Based-Model was used to give rules to predator-prey relationship, suppression, production, self suppression, etc. of each species. It enabled the emergence of the overall system only

  7. Indirect Evidence Link PCB Dehalogenation with Geobacteraceae in Anaerobic Sediment-Free Microcosms

    PubMed Central

    Praveckova, Martina; Brennerova, Maria V.; Holliger, Christof; De Alencastro, Felippe; Rossi, Pierre

    2016-01-01

    Although polychlorinated biphenyls (PCBs) production was brought to a halt 30 years ago, recalcitrance to degradation makes them a major environmental pollutant at a global scale. Previous studies confirmed that organohalide-respiring bacteria (OHRB) were capable of utilizing chlorinated congeners as electron acceptor. OHRB belonging to the Phyla Chloroflexi and Firmicutes are nowadays considered as the main PCB-dechlorinating organisms. In this study, we aimed at exploring the involvement of other taxa in PCB dechlorination using sediment-free microcosms (SFMs) and the Delor PCB mixture. High rates of congener dehalogenation (up to 96%) were attained in long-term incubations of up to 692 days. Bacterial communities were dominated by Chloroflexi, Proteobacteria, and Firmicutes, among strictly simplified community structures composed of 12 major phyla only. In a first batch of SFMs, Dehalococcoides mccartyi closely affiliated with strains CG4 and CBDB1 was considered as the main actor associated with congener dehalogenation. Addition of 2-bromoethanesulfonate (BES), a known inhibitor of methanogenic activity in a second batch of SFMs had an adverse effect on the abundance of Dehalococcoides sp. Only two sequences affiliated to this Genus could be detected in two (out of six) BES-treated SFMs, contributing to a mere 0.04% of the communities. BES-treated SFMs showed very different community structures, especially in the contributions of organisms involved in fermentation and syntrophic activities. Indirect evidence provided by both statistical and phylogenetic analysis validated the implication of a new cluster of actors, distantly affiliated with the Family Geobacteraceae (Phylum δ-Proteobacteria), in the dehalogenation of low chlorinated PCB congeners. Members of this Family are known already for their dehalogenation capacity of chlorinated solvents. As a result, the present study widens the knowledge for the phylogenetic reservoir of indigenous PCB dechlorinating

  8. Assessing the Response of Nematode Communities to Climate Change-Driven Warming: A Microcosm Experiment.

    PubMed

    Gingold, Ruth; Moens, Tom; Rocha-Olivares, Axayácatl

    2013-01-01

    Biodiversity has diminished over the past decades with climate change being among the main responsible factors. One consequence of climate change is the increase in sea surface temperature, which, together with long exposure periods in intertidal areas, may exceed the tolerance level of benthic organisms. Benthic communities may suffer structural changes due to the loss of species or functional groups, putting ecological services at risk. In sandy beaches, free-living marine nematodes usually are the most abundant and diverse group of intertidal meiofauna, playing an important role in the benthic food web. While apparently many functionally similar nematode species co-exist temporally and spatially, experimental results on selected bacterivore species suggest no functional overlap, but rather an idiosyncratic contribution to ecosystem functioning. However, we hypothesize that functional redundancy is more likely to observe when taking into account the entire diversity of natural assemblages. We conducted a microcosm experiment with two natural communities to assess their stress response to elevated temperature. The two communities differed in diversity (high [HD] vs. low [LD]) and environmental origin (harsh vs. moderate conditions). We assessed their stress resistance to the experimental treatment in terms of species and diversity changes, and their function in terms of abundance, biomass, and trophic diversity. According to the Insurance Hypothesis, we hypothesized that the HD community would cope better with the stressful treatment due to species functional overlap, whereas the LD community functioning would benefit from species better adapted to harsh conditions. Our results indicate no evidence of functional redundancy in the studied nematofaunal communities. The species loss was more prominent and size specific in the HD; large predators and omnivores were lost, which may have important consequences for the benthic food web. Yet, we found evidence for

  9. Microcosm Approach to Understanding Methane-oxidizing Communities and the Role of Nitrogen Sources

    NASA Astrophysics Data System (ADS)

    Chistoserdova, L.; Hernandez, M. E.; Oshkin, I.

    2014-12-01

    We will report our observations on the dynamics of bacterial communities in response to methane and nitrate stimuli in laboratory microcosm incubations prepared with Lake Washington sediment samples. The experiments were designed to test our hypothesis of methane oxidation as a communal function, with the specific contents of the communities being determined by environmental factors such as oxygen concentration and the nature of the nitrogen source. We first measure taxonomic compositions of long-term oxygenated enrichment cultures and determine that, while dominated by Methylococcaceae bacteria, these cultures also contain accompanying types belonging to a limited number of bacterial taxa, both methylotrophs and non-methylotrophs. We then follow with the short-term community dynamics, under different oxygen tension regimens ('high' to 'low'), different nitrogen source regimens (added nitrate versus no nitrate) and different temperature ranges (10 to 30 oC). We observe rapid loss of species diversity in all incubations, but the composition of the communities depends on the specific environmental factors. Methylobacter represents the major methane-oxidizing partner in the communities incubated at low temperatures while Methylomonas and Methylocystis are more competitive at higher temperatures. All methanotrophs respond positively to nitrate. The non-methanotroph members of the communities reveal different trajectories in response to different oxygen tensions over time, with Methylotenera species persisting under 'low' and Methylophilus species persisting under 'high' oxygen tensions. Metagenomic sequencing reveals successions of different types of the major methane-oxidizing species as well as accompanying species. These types differ in their physiological details such as central carbon meand nitrate metabolism. A broad range of denitrifying capabilities in the organisms forming these stable methane-oxidizing communities is evident from genomic analysis. Our results

  10. Response of Bacterioplankton Communities to Cadmium Exposure in Coastal Water Microcosms with High Temporal Variability

    PubMed Central

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

    2014-01-01

    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, PO43−-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. PMID:25326310

  11. Temporal variation in temperature determines disease spread and maintenance in Paramecium microcosm populations.

    PubMed

    Duncan, Alison B; Fellous, Simon; Kaltz, Oliver

    2011-11-22

    The environment is rarely constant and organisms are exposed to temporal and spatial variations that impact their life histories and inter-species interactions. It is important to understand how such variations affect epidemiological dynamics in host-parasite systems. We explored effects of temporal variation in temperature on experimental microcosm populations of the ciliate Paramecium caudatum and its bacterial parasite Holospora undulata. Infected and uninfected populations of two P. caudatum genotypes were created and four constant temperature treatments (26°C, 28°C, 30°C and 32°C) compared with four variable treatments with the same mean temperatures. Variable temperature treatments were achieved by alternating populations between permissive (23°C) and restrictive (35°C) conditions daily over 30 days. Variable conditions and high temperatures caused greater declines in Paramecium populations, greater fluctuations in population size and higher incidence of extinction. The additional effect of parasite infection was additive and enhanced the negative effects of the variable environment and higher temperatures by up to 50 per cent. The variable environment and high temperatures also caused a decrease in parasite prevalence (up to 40%) and an increase in extinction (absence of detection) (up to 30%). The host genotypes responded similarly to the different environmental stresses and their effect on parasite traits were generally in the same direction. This work provides, to our knowledge, the first experimental demonstration that epidemiological dynamics are influenced by environmental variation. We also emphasize the need to consider environmental variance, as well as means, when trying to understand, or predict population dynamics or range. PMID:21450730

  12. Streambed sediment controls on hyporheic greenhouse gas production - a microcosm experiment

    NASA Astrophysics Data System (ADS)

    Romejn, Paul; Comer, Sophie; Gooddy, Daren; Ullah, Sami; Hannah, David; Krause, Stefan

    2016-04-01

    Hyporheic zones, as the interfaces between groundwater and surface water, can contribute significantly to whole stream carbon respiration. The drivers and controls of rates and magnitude of hyporheic greenhouse gas (GHG) production remain poorly understood. Recent research has hypothesised that nitrous oxide emissions resulting from incomplete denitrification in nutrient rich agricultural streams may contribute substantially to GHG emissions. This paper reports on a controlled microcosm incubation experiment that has been set up to quantify the sensitivity of hyporheic zone GHG production to temperature and nutrient concentrations. Experiments were conducted with sediment from two contrasting UK lowland rivers (sandstone and chalk). Adopting a gradient approach, sediments with different organic matter and carbon content were analysed from both rivers. Our analytical approach integrated several novel methods, such as push-pull application of the Resazurin/Resorufin smart tracer system for estimation of sediment microbial metabolic activity, high-resolution gas sampling and analysis of methane, carbon dioxide and nitrous oxide by gas chromatography with mass spectrometry, coupled with and high precision in-situ dissolved oxygen measurements. Our results indicate strong temperature controls of GHG production rates, overlapping with the observed impacts of different sediment types. Experimental findings indicate that increased hyporheic temperatures during increasing baseflow and drought conditions may enhance substantially sediment respiration and thus, GHG emissions from the streambed interface. The presented results integrated with field experiments of respiration and GHG emission rates under different treatments. This research advances understanding of scale dependent drivers and controls of whole stream carbon and nitrogen budgets and the role of streambed interfaces in GHG emissions.

  13. Streambed sediment controls on hyporheic greenhouse gas production - a microcosm experiment

    NASA Astrophysics Data System (ADS)

    Romeijn, P.; Comer, S.; Krause, S.; Hannah, D. M.; Gooddy, D.

    2015-12-01

    Hyporheic zones, as the interfaces between groundwater and surface water, can contribute significantly to whole stream carbon respiration. The drivers and controls of rates and magnitude of hyporheic greenhouse gas (GHG) production remain poorly understood. Recent research has hypothesised that nitrous oxide emissions resulting from incomplete denitrification in nutrient rich agricultural streams may contribute substantially to GHG emissions. This paper reports on a controlled microcosm incubation experiment that has been set up to quantify the sensitivity of hyporheic zone GHG production to temperature and nutrient concentrations. Experiments were conducted with sediment from two contrasting UK lowland rivers (sandstone and chalk). Adopting a gradient approach, sediments with different organic matter and carbon content were analysed from both rivers. Our analytical approach integrated several novel methods, such as push-pull application of the Resazurin/Resorufin smart tracer system for estimation of sediment microbial metabolic activity, high-resolution gas sampling and analysis of methane, carbon dioxide and nitrous oxide by gas chromatography with mass spectrometry, coupled with and high precision in-situ dissolved oxygen measurements. Our results indicate strong temperature controls of GHG production rates, overlapping with the observed impacts of different sediment types. Experimental findings indicate that increased hyporheic temperatures during increasing baseflow and drought conditions may enhance substantially sediment respiration and thus, GHG emissions from the streambed interface. The presented results integrated with field experiments of respiration and GHG emission rates under different treatments. This research advances understanding of scale dependent drivers and controls of whole stream carbon and nitrogen budgets and the role of streambed interfaces in GHG emissions.

  14. Growth promotion of Xanthium italicum by application of rhizobacterial isolates of Bacillus aryabhattai in microcosm soil.

    PubMed

    Lee, Sol; Ka, Jong-Ok; Song, Hong-Gyu

    2012-02-01

    This study was conducted using rhizobacteria, which are able to exert beneficial effects upon plant growth in the infertile soil collected from barren lakeside areas. Four strains of plant growth promoting bacteria were isolated from the rhizosphere of a common wild plant, Erigeron canadensis. Isolated strains LS9, LS11, LS12, and LS15 were identified as Bacillus aryabhattai by 16S rDNA sequence analysis. B. aryabhattai LS9, LS11, LS12, and LS15 could solubilize 577.9, 676.8, 623.6, and 581.3 mg/L of 0.5% insoluble calcium phosphate within 2 days of incubation. Production of indole acetic acid, a typical growth promoting phytohormone auxin, by strain LS15 was 471.3 mg/L in 2 days with the addition of auxin precursor L-tryptophan. All the strains also produced other phytohormones such as indole butyric acid, gibberellins, and abscisic acid, and strain LS15 showed the highest production rate of gibberellin (GA(3)), 119.0 μg/mg protein. Isolated bacteria were used in a microcosm test for growth of wild plant Xanthium italicum, which can be utilized as a pioneer plant in barren lands. Seed germination was facilitated, and the lengths of roots, and shoots and the dry weights of germinated seedlings after 16 days were higher than those of the uninoculated control plants. Root lengths of seedlings of X. italicum increased by 121.1% in LS11-treated samples after 16 days. This plant growth-promoting capability of B. aryabhattai strains may be utilized as an environmentally friendly means of revegetating barren lands, especially sensitive areas such as lakeside lands. PMID:22367936

  15. Comparative metagenomic analysis of microcosm structures and lignocellulolytic enzyme systems of symbiotic biomass-degrading consortia.

    PubMed

    Wongwilaiwalin, Sarunyou; Laothanachareon, Thanaporn; Mhuantong, Wuttichai; Tangphatsornruang, Sithichoke; Eurwilaichitr, Lily; Igarashi, Yasuo; Champreda, Verawat

    2013-10-01

    Decomposition of lignocelluloses by cooperative microbial actions is an essential process of carbon cycling in nature and provides a basis for biomass conversion to fuels and chemicals in biorefineries. In this study, structurally stable symbiotic aero-tolerant lignocellulose-degrading microbial consortia were obtained from biodiversified microflora present in industrial sugarcane bagasse pile (BGC-1), cow rumen fluid (CRC-1), and pulp mill activated sludge (ASC-1) by successive subcultivation on rice straw under facultative anoxic conditions. Tagged 16S rRNA gene pyrosequencing revealed that all isolated consortia originated from highly diverse environmental microflora shared similar composite phylum profiles comprising mainly Firmicutes, reflecting convergent adaptation of microcosm structures, however, with substantial differences at refined genus level. BGC-1 comprising cellulolytic Clostridium and Acetanaerobacterium in stable coexistence with ligninolytic Ureibacillus showed the highest capability on degradation of agricultural residues and industrial pulp waste with CMCase, xylanase, and β-glucanase activities in the supernatant. Shotgun pyrosequencing of the BGC-1 metagenome indicated a markedly high relative abundance of genes encoding for glycosyl hydrolases, particularly for lignocellulytic enzymes in 26 families. The enzyme system comprised a unique composition of main-chain degrading and side-chain processing hydrolases, dominated by GH2, 3, 5, 9, 10, and 43, reflecting adaptation of enzyme profiles to the specific substrate. Gene mapping showed metabolic potential of BGC-1 for conversion of biomass sugars to various fermentation products of industrial importance. The symbiotic consortium is a promising simplified model for study of multispecies mechanisms on consolidated bioprocessing and a platform for discovering efficient synergistic enzyme systems for biotechnological application. PMID:23381385

  16. Effect of a simulated oil spill on natural assemblages of marine phytoplankton enclosed in microcosms

    NASA Astrophysics Data System (ADS)

    González, J.; Figueiras, F. G.; Aranguren-Gassis, M.; Crespo, B. G.; Fernández, E.; Morán, X. A. G.; Nieto-Cid, M.

    2009-07-01

    Two microcosm experiments were carried out to simulate the effect of sporadic oil spills derived from tanker accidents on oceanic and coastal marine phytoplankton assemblages. Treatments were designed to reproduce the spill from the Prestige, which took place in Galician coastal waters (NW Iberia) in November 2002. Two different concentrations of the water soluble fraction of oil were used: low (8.6 ± 0.7 μg l -1 of chrysene equivalents) and high (23 ± 5 μg l -1 of chrysene equivalents l -1). Photosynthetic activity and chlorophyll a concentration decreased in both assemblages after 24-72 h of exposure to the two oil concentrations, even though the effect was more severe on the oceanic assemblage. These variables progressively recovered up to values close or higher than those in the controls, but the short-term negative effect of oil, which was generally stronger at the high concentration, also induced changes in the structure of the plankton community. While the biomass of nanoflagellates increased in both assemblages, oceanic picophytoplankton was drastically reduced by the addition of oil. Effects on diatoms were also observed, particularly in the coastal assemblage. The response of coastal diatoms to oil addition showed a clear dependence on size. Small diatoms (<20 μm) were apparently stimulated by oil, whereas diatoms >20 μm were only negatively affected by the high oil concentration. These differences, which could be partially due to indirect trophic interactions, might also be related to different sensitivity of species to PAHs. These results, in agreement with previous observations, additionally show that the negative effect of the water soluble fraction of oil on oceanic phytoplankton was stronger than on coastal phytoplankton.

  17. Temporal variation in temperature determines disease spread and maintenance in Paramecium microcosm populations

    PubMed Central

    Duncan, Alison B.; Fellous, Simon; Kaltz, Oliver

    2011-01-01

    The environment is rarely constant and organisms are exposed to temporal and spatial variations that impact their life histories and inter-species interactions. It is important to understand how such variations affect epidemiological dynamics in host–parasite systems. We explored effects of temporal variation in temperature on experimental microcosm populations of the ciliate Paramecium caudatum and its bacterial parasite Holospora undulata. Infected and uninfected populations of two P. caudatum genotypes were created and four constant temperature treatments (26°C, 28°C, 30°C and 32°C) compared with four variable treatments with the same mean temperatures. Variable temperature treatments were achieved by alternating populations between permissive (23°C) and restrictive (35°C) conditions daily over 30 days. Variable conditions and high temperatures caused greater declines in Paramecium populations, greater fluctuations in population size and higher incidence of extinction. The additional effect of parasite infection was additive and enhanced the negative effects of the variable environment and higher temperatures by up to 50 per cent. The variable environment and high temperatures also caused a decrease in parasite prevalence (up to 40%) and an increase in extinction (absence of detection) (up to 30%). The host genotypes responded similarly to the different environmental stresses and their effect on parasite traits were generally in the same direction. This work provides, to our knowledge, the first experimental demonstration that epidemiological dynamics are influenced by environmental variation. We also emphasize the need to consider environmental variance, as well as means, when trying to understand, or predict population dynamics or range. PMID:21450730

  18. Decay of host-associated Bacteroidales cells and DNA in continuous-flow freshwater and seawater microcosms of identical experimental design and temperature as measured by PMA-qPCR and qPCR.

    PubMed

    Bae, Sungwoo; Wuertz, Stefan

    2015-03-01

    It is difficult to compare decay kinetics for genetic markers in an environmental context when they have been determined at different ambient temperatures. Therefore, we investigated the persistence of the host-associated genetic markers BacHum, BacCow and BacCan as well as the general Bacteroidales marker BacUni in both intact Bacteroidales cells and as total intracellular and extracellular marker DNA in controlled batch experiments at two temperatures using PMA-qPCR. Fecal Bacteroidales cells and DNA persisted longer at the lower temperature. Using the modified Arrhenius function to calculate decay constants for the same temperature, we then compared the decay of host-associated Bacteroidales cells and their DNA at 14 °C in field-based flow-through microcosms containing human, cow, and dog feces suspended in freshwater or seawater and previously operated with an identical experimental design. The time for a 2-log reduction (T₉₉) was used to characterize host-associated Bacteroidales decay. Host-associated genetic markers as determined by qPCR had similar T₉₉ values in freshwater and seawater at 14 °C when compared under both sunlight and dark conditions. In contrast, intact Bacteroidales cells measured by PMA-qPCR had shorter T₉₉ values in seawater than in freshwater. The decay constants of Bacteroidales cells were a function of physical (temperature) and chemical (salinity) parameters, suggesting that environmental parameters are key input variables for Bacteroidales survival in a predictive water quality model. Molecular markers targeting total Bacteroidales DNA were less susceptible to the variance of temperature, salinity and sunlight, implying that measurement of markers in both intact cells and DNA could enhance the predictive power of identifying fecal pollution across all aquatic environments. Monitoring Bacteroidales by qPCR alone rather than by PMA-qPCR does not always identify the contribution of recent fecal contamination because a

  19. Microcosm Studies to Evaluate Aerobic Cometabolism of Low Concentrations of 1,4-Dioxane by Isobutane-utilizing Microorganisms in the Presence of Chlorinated Solvent Co-contaminants

    NASA Astrophysics Data System (ADS)

    Rolston, H. M.; Azizian, M.; Hyman, M. R.; Semprini, L.

    2015-12-01

    Due to its use as a stabilizer for chlorinated solvents, 1,4-dioxane (1,4D), a probable human carcinogen, is a common co-contaminant in solvent spills at industrial and military sites and landfills. Its persistence in large groundwater plumes at low concentrations makes it a relevant candidate for in-situ bioremediation via cometabolism. Microcosm studies are being performed to evaluate the capability of aerobic microorganisms to cometabolize mixtures of 1,4D and chlorinated solvents, such as trichloroethylene (TCE), 1,1,1-trichloroethane (1,1,1TCA), and 1,1-dichloroethene (1,1DCE), with isobutane as the primary substrate. Microcosms were constructed using aquifer solids from Fort Carson, Colorado, a site contaminated with 1,4D and TCE, to assess the isobutane uptake and transformation of 1,4D and chlorinated solvents by microorganisms native to the site. Additional microcosms were augmented with Rhodococcus rhodochrous, a bacterium shown to cometabolize 1,4D and chlorinated solvents. Results indicate that native microcosms cometabolized 1,4D upon stimulation with isobutane after a lag period of about 15 days. TCE was also transformed, but at significantly slower rates. The presence of 1,4D and TCE at 500 and 300 ppb, respectively, did not inhibit the growth of native microorganisms on isobutane, with isobutane uptake and 1,4D transformation occurring simultaneously. Bioaugmented microcosms transformed 1,4D immediately after inoculation with R. rhodochrous. Tests in bioaugmented microorganisms indicated that the presence of TCE at low concentrations inhibits but does not block the transformation of 1,4D. Results from the microcosms will be used to design field tests to be performed at Fort Carson. Additional microcosm studies will compare the stimulation of native and bioaugmented microcosms and the transformation of mixtures of 1,4D, 1,1,1TCA and 1,1DCE. Molecular methods will analyze the monoxygenase enzymes expressed in the native and bioaugmented microcosms.

  20. Feasible pickup from intact ossicular chain with floating piezoelectric microphone

    PubMed Central

    2012-01-01

    Objectives Many microphones have been developed to meet with the implantable requirement of totally implantable cochlear implant (TICI). However, a biocompatible one without destroying the intactness of the ossicular chain still remains under investigation. Such an implantable floating piezoelectric microphone (FPM) has been manufactured and shows an efficient electroacoustic performance in vitro test at our lab. We examined whether it pick up sensitively from the intact ossicular chain and postulated whether it be an optimal implantable one. Methods Animal controlled experiment: five adult cats (eight ears) were sacrificed as the model to test the electroacoustic performance of the FPM. Three groups were studied: (1) the experiment group (on malleus): the FPM glued onto the handle of the malleus of the intact ossicular chains; (2) negative control group (in vivo): the FPM only hung into the tympanic cavity; (3) positive control group (Hy-M30): a HiFi commercial microphone placed close to the site of the experiment ear. The testing speaker played pure tones orderly ranged from 0.25 to 8.0 kHz. The FPM inside the ear and the HiFi microphone simultaneously picked up acoustic vibration which recorded as .wav files to analyze. Results The FPM transformed acoustic vibration sensitively and flatly as did the in vitro test across the frequencies above 2.0 kHz, whereas inefficiently below 1.0 kHz for its overloading mass. Although the HiFi microphone presented more efficiently than the FPM did, there was no significant difference at 3.0 kHz and 8.0 kHz. Conclusions It is feasible to develop such an implantable FPM for future TICIs and TIHAs system on condition that the improvement of Micro Electromechanical System and piezoelectric ceramic material technology would be applied to reduce its weight and minimize its size. PMID:22353161

  1. An integrated workflow for characterizing intact phosphoproteins from complex mixtures

    PubMed Central

    Wu, Si; Yang, Feng; Zhao, Rui; Tolić, Nikola; Robinson, Errol W.; Camp, David; Smith, Richard D.; Paša-Tolić, Ljiljana

    2014-01-01

    The phosphorylation of any site on a given protein can affect its activity, degradation rate, ability to dock with other proteins or bind divalent cations, and/or its localization. These effects can operate within the same protein; in fact, multisite phosphorylation is a key mechanism for achieving signal integration in cells. Hence, knowing the overall phosphorylation signature of a protein is essential for understanding the "state" of a cell. However, current technologies to monitor the phosphorylation status of proteins are inefficient at determining the relative stoichiometries of phosphorylation at multiple sites. Here we report a new capability for comprehensive liquid chromatography mass spectrometry (LC/MS) analysis of intact phosphoproteins. The technology platform built upon integrated bottom-up and top-down approach that is facilitated by intact protein reversed-phase (RP)LC concurrently coupled with Fourier transform ion cyclotron resonance (FTICR) MS and fraction collection. As the use of conventional RPLC systems for phosphopeptide identification has proven challenging due to the formation of metal ion complexes at various metal surfaces during LC/MS and ESI-MS analysis, we have developed a “metal-free” RPLC-ESI-MS platform for phosphoprotein characterization. This platform demonstrated a significant sensitivity enhancement for phosphorylated casein proteins enriched from a standard protein mixture and revealed the presence of over 20 casein isoforms arising from genetic variants with varying numbers of phosphorylation sites. The integrated workflow was also applied to an enriched yeast phosphoproteome to evaluate the feasibility of this strategy for characterizing complex biological systems, and revealed ~16% of the detected yeast proteins to have multiple phosphorylation isoforms. Intact protein LC/MS platform for characterization of combinatorial posttranslational modifications (PTMs), with special emphasis on multisite phosphorylation, holds

  2. Fast imaging of intact and shattered cryogenic neon pellets.

    PubMed

    Wang, Zhehui; Combs, S K; Baylor, L R; Foust, C R; Lyttle, M S; Meitner, S J; Rasmussen, D A

    2014-11-01

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100-µm- and sub-µs-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of µm to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development. PMID:25430370

  3. Fast Imaging of Intact and Shattered Cryogenic Neon Pellets

    SciTech Connect

    Wang, Zhehui; Combs, Stephen Kirk; Baylor, Larry R; Foust, Charles R; Lyttle, Mark S; Meitner, Steven J; Rasmussen, David A

    2014-01-01

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100- m- and sub- s-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of m to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development.

  4. Fast imaging of intact and shattered cryogenic neon pellets

    SciTech Connect

    Wang, Zhehui; Combs, S. K.; Baylor, L. R.; Foust, C. R.; Lyttle, M. S.; Meitner, S. J.; Rasmussen, D. A.

    2014-11-15

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100-µm- and sub-µs-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of µm to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development.

  5. Physiological characterization of motor unit properties in intact cats.

    PubMed

    O'Donovan, M J; Hoffer, J A; Loeb, G E

    1983-02-01

    Single motor units were isolated in intact cats, by microstimulation through chronically implanted microwires in the L5 ventral roots. Motor unit axonal and mechanical properties were obtained by stimulus-triggered averaging the signals from an implanted femoral nerve recording cuff and patellar tendon force transducer. All unit types were sampled with this technique, and it was also possible to stimulate in isolation an axon whose ventral root spike was recorded during treadmill locomotion. A new technique was described, spike-triggered microstimulation, for verifying the identity of a stimulated and a recorded axon. PMID:6300565

  6. Controlled therapy by imaging of functional structures of intact liver

    NASA Astrophysics Data System (ADS)

    Wang, W.; Zhuang, Feng Y.; Ruan, G.; Kakihana, Yasuyuki; Krug, A.; Kessler, Manfred D.

    2000-04-01

    Ligustrazine, a Chinese herb medicine has been used to treat the diseases of cardiovascular and cerebral vascular diseases in China by Chinese traditional physicians or many years. Recently, results showed that ligustrazine is a powerful hepatic vasodilator. It can greatly change the blood supply of the tissues. Due to micro-optical tissue sensor developed recently it became possible to image functional structures of tissue on the level of intact blood capillaries. In our experiment we used the Oxyscan in order to study the effect of Ligustrazine on the oxygen supply of rat liver.

  7. From a microcosm to the catchment scale: studying the fate of organic runoff pollutants in aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Böttcher, T.; Schroll, R.

    2009-04-01

    Spray-drift, drainage, erosion and runoff events are the major causes responsible for deportation of agrochemicals as micropollutants to aquatic non-target sites. These processes can lead to the contamination of nearby freshwater ecosystems with considerably high concentrations of xenobiotics. Thus, it is important to unravel the fate of these pollutants and to evaluate their ecological effects. A novel approach to address this goal was established by the development of a microcosm with multiple sampling abilities enabling quantitative assessment of organic volatilisation, mineralization, metabolization and distribution within the aquatic ecosystem. This microcosm system was designed to support modelling approaches of the catchment scale and gain insights into the fate of pesticides simulating a large scale water body. The potential of this microcosm was exemplified for Isoproturon (IPU), a phenylurea derived systemic herbicide, which is frequently found as contaminant in water samples and with the free-floating macrophyte Lemna minor as non-target species, that is common to occur in rural water bodies. During 21 days exposure time, only a small amount of 14C labeled IPU was removed from the aquatic medium. The major portion (about 5%) was accumulated by Lemna minor resulting in a BCF of 15.8. IPU-volatilisation was very low with 0.13% of the initially applied herbicide. Only a minor amount of IPU was completely metabolized, presumably by rhizosphere microorganisms and released as 14CO2. The novel experimental system allowed to quantitatively investigate the fate of IPU and showed a high reproducibility with a mean average 14C-recovery rate of 97.1

  8. Persistence of microbial and chemical pig manure markers as compared to faecal indicator bacteria survival in freshwater and seawater microcosms.

    PubMed

    Solecki, O; Jeanneau, L; Jardé, E; Gourmelon, M; Marin, C; Pourcher, A M

    2011-10-01

    Natural seawater and freshwater microcosms inoculated with pig manure were set up to determine the persistence of pig faecal microbial and chemical markers in these two types of surface water. The concentrations of Lactobacillus amylovorus, the Bacteroidales Pig-2-Bac 16S rRNA genetic marker, five stanols and the evolution of two ratios of stanols, R1 (coprostanol to the sum of coprostanol and 24-ethylcoprostanol) and R2 (sitostanol to coprostanol) were analyzed during two months along with the concentration of Faecal Indicator Bacteria (FIB). Pig manure was inoculated to unfiltered water microcosms incubated aerobically at 18 °C in the dark. The faecal contamination load represented by the concentrations of culturable Escherichia coli and/or enterococci remained for two months in the freshwater and seawater microcosms water column. These concentrations followed a biphasic decay pattern with a 97% reduction of the initial amount during a first rapid phase (<6 days) and a remaining proportion undergoing a slower or null second decline. The L. amylovorus marker and five stanols persisted as long as the indicators in both treatments. The Pig-2-Bac marker persisted 20 and 27 days in seawater and freshwater, respectively. The ratios R1 and R2 were in the range specific to pig manure until day 6 in both types of water. These results indicate that Pig-2-Bac, L. amylovorus and stanol ratios might be used in combination to complement FIB testing to determine the pig source of fecal pollution. However, stanol ratios are to be used when the time point of the discharge is known. PMID:21745675

  9. Chlorodifluoroacetic acid fate and toxicity to the macrophytes Lemna gibba, Myriophyllum spicatum, and Myriophyllum sibiricum in aquatic microcosms.

    PubMed

    Hanson, M L; Sibley, P K; Mabury, S A; Muir, D C; Solomon, K R

    2001-12-01

    Chlorodifluoroacetic acid (CDFA) is a novel haloacetic acid (HAA) and has been recently documented in aquatic systems. It is a suspected degradation product of the refrigerants 1,1,2-trichloro-1,1-difluoroethane (CFC-113) and 1-chloro-1,1-difluoroethane (HCFC-142b). Haloacetic acids can be phytotoxic, putatively acting through inhibition of the citric acid cycle. Replicate (n = 3) 12,000-L model aquatic ecosystems (microcosms) were dosed once at 0.5, 1, 5, and 20 mg/L of neutralized CDFA. Three microcosms served as controls. Each microcosm was stocked with eight individual apical shoots of both Myriophyllum spicatum and Myriophyllum sibiricum and sampled at regular intervals over a 42-d exposure period. The plants were assessed for the somatic endpoints of plant length, root growth, node number, and wet and dry mass and the biochemical endpoints of chlorophyll-a/b and carotenoid content as well as citric acid levels. The duckweed Lemna gibba was also introduced into these systems and monitored over a period of 14 d for wet/dry mass, plant/frond number, chlorophyll content, and growth rate. Concentrations of CDFA remained constant in the water column over the course of the fate investigation (241 d), indicating that this compound undergoes little, if any, degradation in aquatic systems. Results showed few statistically significant differences from controls for all three plant species with exposure to CDFA but no biologically relevant impacts. Overall, CDFA does not appear to pose any risk to these aquatic macrophytes at current environmental concentrations. PMID:11764159

  10. Trichloroacetic acid (TCA) and trifluoroacetic acid (TFA) mixture toxicity to the macrophytes Myriophyllum spicatum and Myriophyllum sibiricum in aquatic microcosms.

    PubMed

    Hanson, Mark L; Sibley, Paul K; Mabury, Scott A; Solomon, Keith R; Muir, Derek C G

    2002-02-21

    Trichloroacetic acid (TCA) and trifluoroacetic acid (TFA) have been detected together in environmental water samples throughout the world. TCA may enter into aquatic systems via rainout as the degradation product of chlorinated solvents, herbicide use, as a by-product of water disinfection and from emissions of spent bleach liquor of kraft pulp mills. Sources of TFA include degradation of hydrofluorocarbons (HFCs) refrigerants and pesticides. These substances are phytotoxic and widely distributed in aquatic environments. A study to assess the risk of a binary mixture of TCA and TFA to macrophytes in aquatic microcosms was conducted as part of a larger study on haloacetic acids. M. spicatum and M. sibiricum were exposed to 0.1, 1, 3 and 10 mg/l of both TCA and TFA (neutralized with sodium hydroxide) in replicate (n = 3) 12000 l aquatic microcosms for 49 days in an one-way analysis of variance design. Each microcosm was stocked with 14 individual apical shoots per species. The plants were sampled at regular intervals and assessed for the somatic endpoints of plant length, root growth, number of nodes and wet and dry mass and the biochemical endpoints of chlorophyll-a, chlorophyll-b, carotenoid content and citric acid levels. Results indicate that there were statistically significant effects of the TCA/TFA mixture on certain pigment concentrations immediately after the start of exposure (2-7 days), but the plants showed no signs of stress thereafter. These data suggest that TCA/TFA mixtures at environmentally relevant concentrations do not pose a significant risk to these aquatic macrophytes. PMID:11878273

  11. Hydrocarbon Specificity During Aerobic oil Biodegradation Revealed in Marine Microcosms With the use of Comprehensive, Two-Dimensional Gas Chromatography.

    NASA Astrophysics Data System (ADS)

    Wardlaw, G. D.; Reddy, C. M.; Nelson, R. K.; Valentine, D. L.

    2008-12-01

    In 2003 the National Research Council reported more than 380 million gallons of oil is emitted into the ocean each year from natural seepage and as a result of anthropogenic activities. Many of the hydrocarbons making up this oil are persistent and toxic to marine life. Petroleum emitted into biologically sensitive areas can lead to environmental stress and ecosystem collapse. As a result many studies and a substantial amount of resources have been devoted to creating efficient and effective remediation tools and developing a better understanding of natural hydrocarbon weathering processes occurring in marine environments. The goal of this study is to elucidate patterns and extent of aerobic hydrocarbon degradation in marine sediments. In order to assess the specific molecular transformations occurring in petroleum emitted into oxic marine environments, we prepared microcosm experiments using sediments and seawater collected from the natural oil seeps offshore Coal Oil Point, California. Petroleum recovered from Platform Holly in the Santa Barbara Channel, was added to a sediment-seawater mixture and the microcosm bottles were allowed to incubate under aerobic conditions for slightly more than 100 days. Comprehensive, two-dimensional gas chromatography was employed in this study to quantify changes in the concentrations of individual hydrocarbon compounds because of the increased resolution and resolving power provided with this robust analytical method. We show significant hydrocarbon mass loss due to aerobic biodegradation for hundreds of tracked compounds in the microcosm bottles. The results shown here provide quantitative evidence for broad-scale metabolic specificity during aerobic hydrocarbon degradation in surface and shallow subsurface marine sediments.

  12. Microarray Noninvasive Neuronal Seizure Recordings from Intact Larval Zebrafish

    PubMed Central

    Meyer, Michaela; Dhamne, Sameer C.; LaCoursiere, Christopher M.; Tambunan, Dimira; Poduri, Annapurna; Rotenberg, Alexander

    2016-01-01

    Zebrafish epilepsy models are emerging tools in experimental epilepsy. Zebrafish larvae, in particular, are advantageous because they can be easily genetically altered and used for developmental and drug studies since agents applied to the bath penetrate the organism easily. Methods for electrophysiological recordings in zebrafish are new and evolving. We present a novel multi-electrode array method to non-invasively record electrical activity from up to 61 locations of an intact larval zebrafish head. This method enables transcranial noninvasive recording of extracellular field potentials (which include multi-unit activity and EEG) to identify epileptic seizures. To record from the brains of zebrafish larvae, the dorsum of the head of an intact larva was secured onto a multi-electrode array. We recorded from individual electrodes for at least three hours and quantified neuronal firing frequency, spike patterns (continuous or bursting), and synchrony of neuronal firing. Following 15 mM potassium chloride- or pentylenetetrazole-infusion into the bath, spike and burst rate increased significantly. Additionally, synchrony of neuronal firing across channels, a hallmark of epileptic seizures, also increased. Notably, the fish survived the experiment. This non-invasive method complements present invasive zebrafish neurophysiological techniques: it affords the advantages of high spatial and temporal resolution, a capacity to measure multiregional activity and neuronal synchrony in seizures, and fish survival for future experiments, such as studies of epileptogenesis and development. PMID:27281339

  13. Enrichment and Analysis of Intact Phosphoproteins in Arabidopsis Seedlings

    PubMed Central

    Aryal, Uma K.; Ross, Andrew R. S.; Krochko, Joan E.

    2015-01-01

    Protein phosphorylation regulates diverse cellular functions and plays a key role in the early development of plants. To complement and expand upon previous investigations of protein phosphorylation in Arabidopsis seedlings we used an alternative approach that combines protein extraction under non-denaturing conditions with immobilized metal-ion affinity chromatography (IMAC) enrichment of intact phosphoproteins in Rubisco-depleted extracts, followed by identification using two-dimensional gel electrophoresis (2-DE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In-gel trypsin digestion and analysis of selected gel spots identified 144 phosphorylated peptides and residues, of which only18 phosphopeptides and 8 phosphosites were found in the PhosPhAt 4.0 and P3DB Arabidopsis thaliana phosphorylation site databases. More than half of the 82 identified phosphoproteins were involved in carbohydrate metabolism, photosynthesis/respiration or oxidative stress response mechanisms. Enrichment of intact phosphoproteins prior to 2-DE and LC-MS/MS appears to enhance detection of phosphorylated threonine and tyrosine residues compared with methods that utilize peptide-level enrichment, suggesting that the two approaches are somewhat complementary in terms of phosphorylation site coverage. Comparing results for young seedlings with those obtained previously for mature Arabidopsis leaves identified five proteins that are differentially phosphorylated in these tissues, demonstrating the potential of this technique for investigating the dynamics of protein phosphorylation during plant development. PMID:26158488

  14. Effects of Triclocarban on Intact Immature Male Rat

    PubMed Central

    Duleba, Antoni J.; Ahmed, Mohamed I.; Sun, Meng; Gao, Allen C.; Villanueva, Jesus; Conley, Alan J.; Turgeon, Judith L.; Benirschke, Kurt; Gee, Nancy A.; Chen, Jiangang; Green, Peter G.; Lasley, Bill L.

    2011-01-01

    Triclocarban (TCC; 3,4,4′-trichlorocarbanilide) is an antimicrobial agent used widely in various personal hygiene products including soaps. Recently, TCC has been shown to enhance testosterone-induced effects in vitro and to enlarge accessory sex organs in castrated male rats. This study was designed to evaluate the effects of TCC on intact age-matched male rats and on human prostate LNCaP and C4–2B cells. Seven-week-old male Sprague-Dawley rats received either a normal diet or a diet supplemented with TCC (0.25% in diet) for 10 days. Triclocarban induced hyperplasia of accessory sex organs in the absence of significant qualitative histological changes. Serum luteinizing hormone (LH) and testosterone were not significantly altered by TCC treatment. In prostate cancer-derived LNCaP and C4–2B cells, TCC potentiated androgen actions via androgen receptor-dependent actions. In conclusion, TCC significantly affects intact male reproductive organs and potentiates androgen effects in prostate cancer cells. PMID:20889956

  15. Multiplexed Intact-Tissue Transcriptional Analysis at Cellular Resolution.

    PubMed

    Sylwestrak, Emily Lauren; Rajasethupathy, Priyamvada; Wright, Matthew Arnot; Jaffe, Anna; Deisseroth, Karl

    2016-02-11

    In recently developed approaches for high-resolution imaging within intact tissue, molecular characterization over large volumes has been largely restricted to labeling of proteins. But volumetric nucleic acid labeling may represent a far greater scientific and clinical opportunity, enabling detection of not only diverse coding RNA variants but also non-coding RNAs. Moreover, scaling immunohistochemical detection to large tissue volumes has limitations due to high cost, limited renewability/availability, and restricted multiplexing capability of antibody labels. With the goal of versatile, high-content, and scalable molecular phenotyping of intact tissues, we developed a method using carbodiimide-based chemistry to stably retain RNAs in clarified tissue, coupled with amplification tools for multiplexed detection. The resulting technology enables robust measurement of activity-dependent transcriptional signatures, cell-identity markers, and diverse non-coding RNAs in rodent and human tissue volumes. The growing set of validated probes is deposited in an online resource for nucleating related developments from across the scientific community. PMID:26871636

  16. A method for immunolabeling neurons in intact cuticularized insect appendages.

    PubMed

    Ehrhardt, Erica; Kleele, Tatjana; Boyan, George

    2015-06-01

    The antennae of the grasshopper Schistocerca gregaria possess a pair of nerve pathways which are established by so-called pioneer neurons early in embryonic development. Subsequently, sensory cell clusters mediating olfaction, flight, optomotor responses, and phase changes differentiate from the antennal epithelium at stereotypic locations and direct their axons onto those of the pioneers to then project to the brain. Early in embryonic development, before the antennae become cuticularized, immunolabeling can be used to follow axogenesis in these pioneers and sensory cells. At later stages, immunolabeling becomes problematical as the cuticle is laid down and masks internal antigen sites. In order to immunolabel the nervous system of cuticularized late embryonic and first instar grasshopper antennae, we modified a procedure known as sonication in which the appendage is exposed to ultrasound thereby rendering it porous to antibodies. Comparisons of the immunolabeled nervous system of sectioned and sonicated antennae show that the cellular organization of sensory clusters and their axon projections is intact. The expression patterns of neuron-specific, microtubule-specific, and proliferative cell-specific labels in treated antennae are consistent with those reported for earlier developmental stages where sonication is not necessary, suggesting that these molecular epitopes are also conserved. The method ensures reliable immunolabeling in intact, cuticularized appendages so that the peripheral nervous system can be reconstructed directly via confocal microscopy throughout development. PMID:25868908

  17. Multivariate analysis of the impacts of the turbine fuel JP-4 in a microcosm toxicity test with implications for the evaluation of ecosystem dynamics and risk assessment.

    PubMed

    Landis, W G; Matthews, R A; Markiewicz, A J; Matthews, G B

    1993-12-01

    Turbine fuels are often the only aviation fuel available in most of the world. Turbine fuels consist of numerous constituents with varying water solubilities, volatilities and toxicities. This study investigates the toxicity of the water soluble fraction (WSF) of JP-4 using the Standard Aquatic Microcosm (SAM). Multivariate analysis of the complex data, including the relatively new method of nonmetric clustering, was used and compared to more traditional analyses. Particular emphasis is placed on ecosystem dynamics in multivariate space.The WSF is prepared by vigorously mixing the fuel and the SAM microcosm media in a separatory funnel. The water phase, which contains the water-soluble fraction of JP-4 is then collected. The SAM experiment was conducted using concentrations of 0.0, 1.5 and 15% WSF. The WSF is added on day 7 of the experiments by removing 450 ml from each microcosm including the controls, then adding the appropriate amount of toxicant solution and finally bringing the final volume to 3 L with microcosm media. Analysis of the WSF was performed by purge and trap gas chromatography. The organic constituents of the WSF were not recoverable from the water column within several days of the addition of the toxicant. However, the impact of the WSF on the microcosm was apparent. In the highest initial concentration treatment group an algal bloom ensued, generated by the apparent toxicity of the WSF of JP-4 to the daphnids. As the daphnid populations recovered the algal populations decreased to control values. Multivariate methods clearly demonstrated this initial impact along with an additional oscillation seperating the four treatment groups in the latter segment of the experiment. Apparent recovery may be an artifact of the projections used to describe the multivariate data. The variables that were most important in distinguishing the four groups shifted during the course of the 63 day experiment. Even this simple microcosm exhibited a variety of dynamics

  18. Linking Stoichiometric Homeostasis of Microorganisms with Soil Phosphorus Dynamics in Wetlands Subjected to Microcosm Warming

    PubMed Central

    Wang, Hang; Li, HongYi; Zhang, ZhiJian; Muehlbauer, Jeffrey D.; He, Qiang; Xu, XinHua; Yue, ChunLei; Jiang, DaQian

    2014-01-01

    Soil biogeochemical processes and the ecological stability of wetland ecosystems under global warming scenarios have gained increasing attention worldwide. Changes in the capacity of microorganisms to maintain stoichiometric homeostasis, or relatively stable internal concentrations of elements, may serve as an indicator of alterations to soil biogeochemical processes and their associated ecological feedbacks. In this study, an outdoor computerized microcosm was set up to simulate a warmed (+5°C) climate scenario, using novel, minute-scale temperature manipulation technology. The principle of stoichiometric homeostasis was adopted to illustrate phosphorus (P) biogeochemical cycling coupled with carbon (C) dynamics within the soil-microorganism complex. We hypothesized that enhancing the flux of P from soil to water under warming scenarios is tightly coupled with a decrease in homeostatic regulation ability in wetland ecosystems. Results indicate that experimental warming impaired the ability of stoichiometric homeostasis (H) to regulate biogeochemical processes, enhancing the ecological role of wetland soil as an ecological source for both P and C. The potential P flux from soil to water ranged from 0.11 to 34.51 mg m−2 d−1 in the control and 0.07 to 61.26 mg m−2 d−1 in the warmed treatment. The synergistic function of C-P acquisition is an important mechanism underlying C∶P stoichiometric balance for soil microorganisms under warming. For both treatment groups, strongly significant (p<0.001) relationships fitting a negative allometric power model with a fractional exponent were found between n-HC∶P (the specialized homeostatic regulation ability as a ratio of soil highly labile organic carbon to dissolved reactive phosphorus in porewater) and potential P flux. Although many factors may affect soil P dynamics, the n-HC∶P term fundamentally reflects the stoichiometric balance or interactions between the energy landscape (i.e., C) and flow of resources

  19. Examination of a smallest CELSS (microcosm) through an individual-based model simulation

    NASA Astrophysics Data System (ADS)

    Ishikawa, Y.; Yoshida, H.; Kinoshita, M.; Murakami, A.; Sugiura, K.

    2004-01-01

    Research of the effect of space environment on an ecosystem consisting of plants and animals is essential when they are to be positively used in space. Although there have been experiments on various organisms under space environment in the past, they mainly studied the effect of space environment on an individual organism or a single species. Microcosm is drawing attention as an experimental material of an ecosystem consisting of multiple species. The object in this research is to understand the nature of this network system called ecosystem. Thus, a mixed microorganism culturing system consisting of three types of microorganisms which form a minimum food chain system as a closed ecosystem (chlorella as the producer, bacteria as the decomposer, and rotifer as the consumer) was taken for the subject, on which to research the universal characteristics of ecosystems. From the results of experiments under the terrestrial environment, formation of colonies, which is an ecological structure, has been observed at its mature stage. The organisms form an optimal substance circulation system. Therefore, formation of colonies in simulation models is important. Many attempts have been made to create ecosystem models. For example, the Lotka-Volterra model forms a simultaneous equation with the differential equation expressing predator and prey relationship and many numerical calculations have been conducted on various ecosystems based on expanded L-V models. Conventionally, these top-down methods have been used. However, since this method only describes the average concentration of organisms that are distributed uniformly throughout the system and cannot express the spatial structure of the system, it was difficult to express ecosystem structures like colonies and density distributions. In actual ecosystems, there is heterogeneity in the number of individuals and in substance density, and this is thought to have great significance in ecosystems. Consequently, an individual

  20. Linking variations in sea spray aerosol particle hygroscopicity to composition during two microcosm experiments

    NASA Astrophysics Data System (ADS)

    Forestieri, Sara D.; Cornwell, Gavin C.; Helgestad, Taylor M.; Moore, Kathryn A.; Lee, Christopher; Novak, Gordon A.; Sultana, Camille M.; Wang, Xiaofei; Bertram, Timothy H.; Prather, Kimberly A.; Cappa, Christopher D.

    2016-07-01

    The extent to which water uptake influences the light scattering ability of marine sea spray aerosol (SSA) particles depends critically on SSA chemical composition. The organic fraction of SSA can increase during phytoplankton blooms, decreasing the salt content and therefore the hygroscopicity of the particles. In this study, subsaturated hygroscopic growth factors at 85 % relative humidity (GF(85 %)) of predominately submicron SSA particles were quantified during two induced phytoplankton blooms in marine aerosol reference tanks (MARTs). One MART was illuminated with fluorescent lights and the other was illuminated with sunlight, referred to as the "indoor" and "outdoor" MARTs, respectively. Optically weighted GF(85 %) values for SSA particles were derived from measurements of light scattering and particle size distributions. The mean optically weighted SSA diameters were 530 and 570 nm for the indoor and outdoor MARTs, respectively. The GF(85 %) measurements were made concurrently with online particle composition measurements, including bulk composition (using an Aerodyne high-resolution aerosol mass spectrometer) and single particle (using an aerosol time-of-flight mass spectrometer) measurement, and a variety of water-composition measurements. During both microcosm experiments, the observed optically weighted GF(85 %) values were depressed substantially relative to pure inorganic sea salt by 5 to 15 %. There was also a time lag between GF(85 %) depression and the peak chlorophyll a (Chl a) concentrations by either 1 (indoor MART) or 3-to-6 (outdoor MART) days. The fraction of organic matter in the SSA particles generally increased after the Chl a peaked, also with a time lag, and ranged from about 0.25 to 0.5 by volume. The observed depression in the GF(85 %) values (relative to pure sea salt) is consistent with the large observed volume fractions of non-refractory organic matter (NR-OM) comprising the SSA. The GF(85 %) values exhibited a reasonable negative

  1. Evaluation of the biodegradation of Alaska North Slope oil in microcosms using the biodegradation model BIOB.

    PubMed

    Torlapati, Jagadish; Boufadel, Michel C

    2014-01-01

    We present the details of a numerical model, BIOB that is capable of simulating the biodegradation of oil entrapped in the sediment. The model uses Monod kinetics to simulate the growth of bacteria in the presence of nutrients and the subsequent consumption of hydrocarbons. The model was used to simulate experimental results of Exxon Valdez oil biodegradation in laboratory columns (Venosa et al., 2010). In that study, samples were collected from three different islands: Eleanor Island (EL107), Knight Island (KN114A), and Smith Island (SM006B), and placed in laboratory microcosms for a duration of 168 days to investigate oil bioremediation through natural attenuation and nutrient amendment. The kinetic parameters of the BIOB model were estimated by fitting to the experimental data using a parameter estimation tool based on Genetic Algorithms (GA). The parameter values of EL107 and KN114A were similar whereas those of SM006B were different from the two other sites; in particular biomass growth at SM006B was four times slower than at the other two islands. Grain size analysis from each site revealed that the specific surface area per unit mass of sediment was considerably lower at SM006B, which suggest that the surface area of sediments is a key control parameter for microbial growth in sediments. Comparison of the BIOB results with exponential decay curves fitted to the data indicated that BIOB provided better fit for KN114A and SM006B in nutrient amended treatments, and for EL107 and KN114A in natural attenuation. In particular, BIOB was able to capture the initial slow biodegradation due to the lag phase in microbial growth. Sensitivity analyses revealed that oil biodegradation at all three locations were sensitive to nutrient concentration whereas SM006B was sensitive to initial biomass concentration due to its slow growth rate. Analyses were also performed to compare the half-lives of individual compounds with that of the overall polycyclic aromatic hydrocarbons

  2. Evaluation of the biodegradation of Alaska North Slope oil in microcosms using the biodegradation model BIOB

    PubMed Central

    Torlapati, Jagadish; Boufadel, Michel C.

    2014-01-01

    We present the details of a numerical model, BIOB that is capable of simulating the biodegradation of oil entrapped in the sediment. The model uses Monod kinetics to simulate the growth of bacteria in the presence of nutrients and the subsequent consumption of hydrocarbons. The model was used to simulate experimental results of Exxon Valdez oil biodegradation in laboratory columns (Venosa et al., 2010). In that study, samples were collected from three different islands: Eleanor Island (EL107), Knight Island (KN114A), and Smith Island (SM006B), and placed in laboratory microcosms for a duration of 168 days to investigate oil bioremediation through natural attenuation and nutrient amendment. The kinetic parameters of the BIOB model were estimated by fitting to the experimental data using a parameter estimation tool based on Genetic Algorithms (GA). The parameter values of EL107 and KN114A were similar whereas those of SM006B were different from the two other sites; in particular biomass growth at SM006B was four times slower than at the other two islands. Grain size analysis from each site revealed that the specific surface area per unit mass of sediment was considerably lower at SM006B, which suggest that the surface area of sediments is a key control parameter for microbial growth in sediments. Comparison of the BIOB results with exponential decay curves fitted to the data indicated that BIOB provided better fit for KN114A and SM006B in nutrient amended treatments, and for EL107 and KN114A in natural attenuation. In particular, BIOB was able to capture the initial slow biodegradation due to the lag phase in microbial growth. Sensitivity analyses revealed that oil biodegradation at all three locations were sensitive to nutrient concentration whereas SM006B was sensitive to initial biomass concentration due to its slow growth rate. Analyses were also performed to compare the half-lives of individual compounds with that of the overall polycyclic aromatic hydrocarbons

  3. Linking stoichiometric homeostasis of microorganisms with soil phosphorus dynamics in wetlands subjected to microcosm warming.

    PubMed

    Wang, Hang; Li, Hongyi; Zhang, Zhijian; Muehlbauer, Jeffrey D; He, Qiang; Xu, Xinhua; Yue, Chunlei; Jiang, Daqian

    2014-01-01

    Soil biogeochemical processes and the ecological stability of wetland ecosystems under global warming scenarios have gained increasing attention worldwide. Changes in the capacity of microorganisms to maintain stoichiometric homeostasis, or relatively stable internal concentrations of elements, may serve as an indicator of alterations to soil biogeochemical processes and their associated ecological feedbacks. In this study, an outdoor computerized microcosm was set up to simulate a warmed (+5°C) climate scenario, using novel, minute-scale temperature manipulation technology. The principle of stoichiometric homeostasis was adopted to illustrate phosphorus (P) biogeochemical cycling coupled with carbon (C) dynamics within the soil-microorganism complex. We hypothesized that enhancing the flux of P from soil to water under warming scenarios is tightly coupled with a decrease in homeostatic regulation ability in wetland ecosystems. Results indicate that experimental warming impaired the ability of stoichiometric homeostasis (H) to regulate biogeochemical processes, enhancing the ecological role of wetland soil as an ecological source for both P and C. The potential P flux from soil to water ranged from 0.11 to 34.51 mg m(-2) d(-1) in the control and 0.07 to 61.26 mg m(-2) d(-1) in the warmed treatment. The synergistic function of C-P acquisition is an important mechanism underlying C∶P stoichiometric balance for soil microorganisms under warming. For both treatment groups, strongly significant (p<0.001) relationships fitting a negative allometric power model with a fractional exponent were found between n-HC∶P (the specialized homeostatic regulation ability as a ratio of soil highly labile organic carbon to dissolved reactive phosphorus in porewater) and potential P flux. Although many factors may affect soil P dynamics, the n-HC∶P term fundamentally reflects the stoichiometric balance or interactions between the energy landscape (i.e., C) and flow of resources

  4. Naturally occurring heavy radioactive elements in the geothermal microcosm of the Los Azufres (Mexico) volcanic complex.

    PubMed

    Abuhani, W A; Dasgupta-Schubert, N; Villaseñor, L M; García Avila, D; Suárez, L; Johnston, C; Borjas, S E; Alexander, S A; Landsberger, S; Suárez, M C

    2015-01-01

    The Los Azufres geothermal complex of central Mexico is characterized by fumaroles and boiling hot-springs. The fumaroles form habitats for extremophilic mosses and ferns. Physico-chemical measurements of two relatively pristine fumarolic microcosms point to their resemblance with the paleo-environment of earth during the Ordovician and Devonian periods. These geothermal habitats were analysed for the distribution of elemental mass fractions in the rhizospheric soil (RS), the native volcanic substrate (VS) and the sediments (S), using the new high-sensitivity technique of polarized x-ray energy dispersive fluorescence spectrometry (PEDXRF) as well as instrumental neutron activation analysis (INAA) for selected elements. This work presents the results for the naturally occurring heavy radioactive elements (NOHRE) Bi, Th and U but principally the latter two. For the RS, the density was found to be the least and the total organic matter content the most. Bi was found to be negligibly present in all substrate types. The average Th and U mass fractions in the RS were higher than in the VS and about equal to their average mass fractions in the S. The VS mass fraction of Th was higher, and of U lower, than the mass fractions in the earth's crust. In fact for the fumaroles of one site, the average RS mass fractions of these elements were higher than the averaged values for S (without considering the statistical dispersion). The immobilization of the NOHRE in the RS is brought about by the bio-geochemical processes specific to these extremophiles. Its effectiveness is such that despite the small masses of these plants, it compares with, or may sometimes exceed, the immobilization of the NOHRE in the S by the abiotic and aggressive chemical action of the hot-springs. These results indicate that the fumarolic plants are able to transform the volcanic substrate to soil and to affect the NOHRE mass fractions even though these elements are not plant nutrients. Mirrored back to

  5. Shifts in Microbial Community Structure with Changes in Cathodic Potential in Marine Sediment Microcosms

    NASA Astrophysics Data System (ADS)

    Lam, B. R.; Rowe, A. R.; Nealson, K. H.

    2014-12-01

    Microorganisms comprise more than 90% of the biomass of the ocean. Their ability to thrive and survive in a wide range of environments from oligotrophic waters to the deep subsurface stems from the great metabolic versatility that exists among them. This metabolic versatility has further expanded with the discovery of extracellular electron transport (EET). EET is the capability of microorganisms to transfer electrons to and from insoluble substrates outside of the cell. Much of what is known about EET comes from studies of model metal reducing microorganisms in the groups Shewanellaceae and Geobacteraceae. However, EET is not limited to these metal reducing microorganisms, and may play a large role in the biogeochemical cycling of several elements. We have developed an electrochemical culturing technique designed to target microorganisms with EET ability and tested these methods in marine sediments. The use of electrodes allows for greater control and quantification of electrons flowing to insoluble substrates as opposed to insoluble substrates such as minerals that are often difficult to measure. We have recently shown that poising electrodes at different redox potentials will enrich for different microbial groups and thus possible metabolisms. In marine sediment microcosms, triplicate electrodes were poised at different cathodic (electron donating) potentials (-300, -400, -500 and -600 mV) and incubated for eight weeks. Community analysis of the 16S rRNA revealed that at lower negative potentials (-500 and -600 mV), more sulfate reducing bacteria in the class Deltaproteobacteria were enriched in comparison to the communities at -300 and -400 mV being dominated by microorganisms within Alphaproteobacteria, Gammaproteobacteria, and Clostridia. This can be explained by sulfate (abundant in seawater) becoming a more energetically favorable electron acceptor with lower applied potentials. In addition, communities at higher potentials showed greater enrichment of the

  6. Degradation of 1,1,2,2-tetrachloroethane and accumulation of vinyl chloride in wetland sediment microcosms and in situ porewater: Biogeochemical controls and associations with microbial communities

    USGS Publications Warehouse

    Lorah, M.M.; Voytek, M.A.

    2004-01-01

    The biodegradation pathways of 1,1,2,2-tetrachloroethane (TeCA) and 1,1,2-trichloroethane (112TCA) and the associated microbial communities in anaerobic wetland sediments were evaluated using concurrent geochemical and genetic analyses over time in laboratory microcosm experiments. Experimental results were compared to in situ porewater data in the wetland to better understand the factors controlling daughter product distributions in a chlorinated solvent plume discharging to a freshwater tidal wetland at Aberdeen Proving Ground, Maryland. Microcosms constructed with wetland sediment from two sites showed little difference in the initial degradation steps of TeCA, which included simultaneous hydrogenolysis to 112TCA and dichloroelimination to 1,2-dichloroethene (12DCE). The microcosms from the two sites showed a substantial difference, however, in the relative dominance of subsequent dichloroelimination of 112TCA. A greater dominance of 112TCA dichloroelimination in microcosms constructed with sediment that was initially iron-reducing and subsequently simultaneously iron-reducing and methanogenic caused approximately twice as much vinyl chloride (VC) production as microcosms constructed with sediment that was methanogenic only throughout the incubation. The microcosms with higher VC production also showed substantially more rapid VC degradation. Field measurements of redox-sensitive constituents, TeCA, and its anaerobic degradation products along flowpaths in the wetland porewater also showed greater production and degradation of VC with concurrent methanogenesis and iron reduction. Molecular fingerprinting indicated that bacterial species [represented by a peak at a fragment size of 198 base pairs (bp) by MnlI digest] are associated with VC production from 112TCA dichloroelimination, whereas methanogens (190 and 307 bp) from the Methanococcales or Methanobacteriales family are associated with VC production from 12DCE hydrogenolysis. Acetate-utilizing methanogens

  7. Monitoring the Dissemination of the Broad-Host-Range Plasmid pB10 in Sediment Microcosms by Quantitative PCR▿ †

    PubMed Central

    Bonot, Sébastien; Merlin, Christophe

    2010-01-01

    Studying the transfer of specific mobile genetic elements in complex environmental matrices remains difficult because suitable molecular tools are not yet available to back up classical culture-dependent approaches. In this report, we show that quantitative PCR could be used to monitor the dissemination of the broad-host-range plasmid pB10 in sediment microcosms. This approach lies in the differential measurement of the host and plasmid DNAs used to inoculate the microcosms, using a particular design of quantitative PCR primers/probes where we took advantage of the mosaic aspect of the bacterial genomes to achieve a highly specific quantitative PCR detection system. PMID:19897757

  8. Degradation of 1,1,2,2-tetrachloroethane and accumulation of vinyl chloride in wetland sediment microcosms and in situ porewater: biogeochemical controls and associations with microbial communities

    NASA Astrophysics Data System (ADS)

    Lorah, Michelle M.; Voytek, Mary A.

    2004-05-01

    The biodegradation pathways of 1,1,2,2-tetrachloroethane (TeCA) and 1,1,2-trichloroethane (112TCA) and the associated microbial communities in anaerobic wetland sediments were evaluated using concurrent geochemical and genetic analyses over time in laboratory microcosm experiments. Experimental results were compared to in situ porewater data in the wetland to better understand the factors controlling daughter product distributions in a chlorinated solvent plume discharging to a freshwater tidal wetland at Aberdeen Proving Ground, Maryland. Microcosms constructed with wetland sediment from two sites showed little difference in the initial degradation steps of TeCA, which included simultaneous hydrogenolysis to 112TCA and dichloroelimination to 1,2-dichloroethene (12DCE). The microcosms from the two sites showed a substantial difference, however, in the relative dominance of subsequent dichloroelimination of 112TCA. A greater dominance of 112TCA dichloroelimination in microcosms constructed with sediment that was initially iron-reducing and subsequently simultaneously iron-reducing and methanogenic caused approximately twice as much vinyl chloride (VC) production as microcosms constructed with sediment that was methanogenic only throughout the incubation. The microcosms with higher VC production also showed substantially more rapid VC degradation. Field measurements of redox-sensitive constituents, TeCA, and its anaerobic degradation products along flowpaths in the wetland porewater also showed greater production and degradation of VC with concurrent methanogenesis and iron reduction. Molecular fingerprinting indicated that bacterial species [represented by a peak at a fragment size of 198 base pairs (bp) by MnlI digest] are associated with VC production from 112TCA dichloroelimination, whereas methanogens (190 and 307 bp) from the Methanococcales or Methanobacteriales family are associated with VC production from 12DCE hydrogenolysis. Acetate-utilizing methanogens

  9. A novel dual-compartment, continuous-flow wetland microcosm to assess cis-dichloroethene removal from the rhizosphere.

    PubMed

    Tawney, Ilisa; Becker, Jennifer G; Baldwin, Andrew H

    2008-01-01

    The anaerobic biodegradation of tetrachloroethene commonly results in the accumulation of chlorinated intermediates such as cis-1,2-dichloroethene (cDCE). Frequently, groundwater contaminated with chlorinated ethenes discharges to natural wetlands. The goal of this study was to quantitatively evaluate the effects of wetland plants and microorganisms on the fate of cDCE in the wetland rhizosphere. To accomplish this goal, a novel dual-compartment wetland microcosm was designed. A Phragmites australis individual was maintained in the microcosm, which was operated with continuous flows of air and mineral medium through the foliar and rhizosphere compartments, respectively, to incorporate mass transfer/transport processes that are important in natural wetlands and allow steady-state assessment of changes in dissolved O2 and cDCE or [1,2-(14)C]cDCE levels. Substantial amounts of [14C]cDCE were phytovolatilized through a healthy P. australis individual to the foliar chamber. Rhizodegradation by native microorganisms associated with P. australis roots also converted substantial amounts of [14C]cDCE to 14C-labeled CO2 and non-volatile compounds, presumably through cometabolic reactions that could be enhanced by the release of O2 and exudates by P. australis. These results suggest that, in some cases, the intrinsic capacity of native wetland plants and microorganisms to remove cDCE from the rhizosphere may be substantial. PMID:19260226

  10. Genotypic responses of bacterial community structure to a mixture of wastewater-borne PAHs and PBDEs in constructed mangrove microcosms.

    PubMed

    Wang, Yafen; Wu, Yan; Wu, Zhenbin; Tam, Nora Fung-Yee

    2015-11-15

    Mangrove microcosms capable of removing polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs) from wastewater were established under everyday tidal and non-tidal flooding regimes, along with two different mangrove species. Defining how bacterial communities change with pollutants or across treatments will contribute to understanding the microbial ecology of in situ bioremediation systems. A semi-nested PCR-DGGE (denaturing gradient gel electrophoresis) approach was employed, with known genus/species-specific primers targeting the 16S rRNA genes of Sphingomonas and Mycobacterium (related to PAH degradation) and Dehalococcoides (related to PBDE degradation). Results showed that the composition of Mycobacterium- and Dehalococcoides-like populations was critically determined by tidal regime during a medium-term (4-8 months) exposure, while that of Sphingomonas-like population, along with total bacterial community, was more dependent on sediment layer and became prominently affected by tidal regime till the end of 8-month treatment. The effect of plant species was relatively small. Canonical correspondence analysis (CCA) further revealed that Sphingomonas- and Mycobacterium-like populations were significantly associated with phenanthrene and benzo(a)pyrene, respectively, while Dehalococcoides-like population was the only group significantly related to the highest PBDE congener (BDE-209) in the mangrove microcosms. PMID:26005923

  11. Bioaugmentation of copper polluted soil microcosms with Amycolatopsis tucumanensis to diminish phytoavailable copper for Zea mays plants.

    PubMed

    Albarracín, Virginia Helena; Amoroso, María Julia; Abate, Carlos Mauricio

    2010-03-01

    Amycolatopsis tucumanensis DSM 45259, the strain of a recently recognized novel species of the genus Amycolatopsis with remarkable copper resistance, was used to bioaugment soil microcosms experimentally polluted with copper and for studying the ability of this strain to effectively diminish phytoavailable copper from soils. Our results demonstrated that A. tucumanensis was capable of profusely colonizing both, copper polluted and non-polluted soil. Copper bioimmobilization ability of A. tucumanensis on soil was assessed measuring the bioavailable copper in the soil solution extracted from polluted soil by using chemical and physical methods and, in this way, 31% lower amounts of the metal were found in soil solution as compared to non-bioaugmented soil. The results obtained when using Zea mays as bioindicator correlated well with the values obtained by the chemical and physical procedures: 20% and 17% lower tissue contents of copper were measured in roots and leaves, respectively. These data confirmed the efficiency of the bioremediation process using A. tucumanensis and at the same time proved that chemical, physical and biological methods for assessing copper bioavailability in soils were correlated. These results suggest a potential use of this strain at large scale in copper soil bioremediation strategies. To our knowledge, this work is the first to apply and to probe the colonization ability of an Amycolatopsis strain in soil microcosms and constitutes the first application of an Amycolatopsis strain on bioremediation of polluted soils. PMID:20163821

  12. Evaluation of the biodegradability of petroleum in microcosm systems by using mangrove sediments from Camamu Bay, Bahia, Brazil.

    PubMed

    Santos, A C F; Rezende, R P; Brendel, M; Souza, S S; Gonçalves, A C S; Dias, J C T

    2014-01-01

    We investigated the biodegradability of oil in mangrove sediment from Camamu Bay and measured its effect on the bacterial community. Microcosms of mangrove sediment were contaminated with 0.1, 0.5, 1, 2, and 5% (w/v) oil, and the microbial activity was compared to that in uncontaminated sediment. The evolution of CO2 and gas chromatography showed the mineralization of oil compounds, which could reach 100%. Bacterial diversity was determined by polymerase chain reaction using a set of primers for the V3 and V6-V8 regions of 16S rDNA. The band profile obtained by denaturing gradient gel electrophoresis of the amplicons that were obtained for the V3 region showed a negative correlation between band number and oil concentration, whereas that of the V6-V8 region showed a positive correlation between band numbers and oil concentration. The latter also gave similar results for microcosms that were contaminated with 2 and 5% oil. These results demonstrate the mangrove sediment's capacity to recover from oil contamination (in vitro) and suggest that native mangrove microorganisms contain enzymes necessary for the catabolism of oil. PMID:24737430

  13. Detection of methylquinoline transformation products in microcosm experiments and in tar oil contaminated groundwater using LC-NMR.

    PubMed

    Reineke, Anne-Kirsten; Preiss, Alfred; Elend, Manfred; Hollender, Juliane

    2008-02-01

    N-heterocyclic compounds are known pollutants at tar oil contaminated sites. Here we report the degradation of methyl-, and hydroxy-methyl-substituted quinolines under nitrate-, sulfate- and iron-reducing conditions in microcosms with aquifer material of a former coke manufacturing site. Comparison of degradation potential and rate under different redox conditions revealed highest degradation activities under sulfate-reducing conditions, the prevailing conditions in the field. Metabolites of methylquinolines, with the exception of 2-methylquinolines, were formed in high amounts in the microcosms and could be identified by (1)H NMR spectroscopy as 2(1H)-quinolinone analogues. 4-Methyl-, 6-methyl-, and 7-methyl-3,4-dihydro-2(1H)-quinolinone, the hydrogenated metabolites in the degradation of quinoline compounds, were identified by high resolution LC-MS. Metabolites of methylquinolines showed persistence, although for the first time a transformation of 4-methylquinoline and its metabolite 4-methyl-2(1H)-quinolinone is described. The relevance of the identified metabolites is supported by the detection of a broad spectrum of them in groundwater of the field site using LC-NMR technique. LC-NMR allowed the differentiation of isomers and identification without reference compounds. A variety of methylated 2(1H)-quinolinones, as well as methyl-3,4-dihydro-2(1H)-quinolinone isomers were not identified before in groundwater. PMID:17936873

  14. Evaluating macroinvertebrate population and community level effects in outdoor microcosms: Use of in situ bioassays and multivariate analysis

    SciTech Connect

    Shaw, J.L.; Manning, J.P.

    1996-05-01

    Evaluating toxicant effects on aquatic communities is difficult due to the ecological complexity at higher levels of organization. Two methods were assessed to improve the understanding of effects on macroinvertebrate communities in aquatic model ecosystems. First, in situ bioassay population effects were used to interpret effects at a higher organization level. Second, canonical discriminant analysis was used to investigate effects on community structure. In situ bioassays were conducted on six occasions in 17-m{sup 3} microcosms treated with copper sulfate. Macroinvertebrates occurring naturally in the microcosms were monitored. Epibenthic in situ bioassays were conducted using Caenis sp. (Ephemeroptera) and Hyalella azteca (Amphipoda) and a water column bioassay was conducted using Notonectidae (Hemiptera). Survival and growth were assessed after 3 d. Effects of copper on both notonectidae and Caenis were observed following application. However, the final Caenis epibenthic bioassays indicated that potential for recovery and survival was {ge}95%. Potential for recovery was less distinct in the water column bioassays. Copper effects also occurred on epibenthic macroinvertebrate populations and communities. Only four taxa, including Caenis, distinguished community differences among copper treatments soon after application. Later, communities showed similarities to the pretreatment bioassay. However, actual recovery was less apparent than the potential for recovery indicated by the bioassays, and community differences due to Caenis persisted.

  15. Microcosm experiments to control anaerobic redox conditions when studying the fate of organic micropollutants in aquifer material.

    PubMed

    Barbieri, Manuela; Carrera, Jesús; Sanchez-Vila, Xavier; Ayora, Carlos; Cama, Jordi; Köck-Schulmeyer, Marianne; López de Alda, Miren; Barceló, Damià; Tobella Brunet, Joana; Hernández García, Marta

    2011-11-01

    The natural processes occurring in subsurface environments have proven to effectively remove a number of organic pollutants from water. The predominant redox conditions revealed to be one of the controlling factors. However, in the case of organic micropollutants the knowledge on this potential redox-dependent behavior is still limited. Motivated by managed aquifer recharge practices microcosm experiments involving aquifer material, settings potentially feasible in field applications, and organic micropollutants at environmental concentrations were carried out. Different anaerobic redox conditions were promoted and sustained in each set of microcosms by adding adequate quantities of electron donors and acceptors. Whereas denitrification and sulfate-reducing conditions are easily achieved and maintained, Fe- and Mn-reduction are strongly constrained by the slower dissolution of the solid phases commonly present in aquifers. The thorough description and numerical modeling of the evolution of the experiments, including major and trace solutes and dissolution/precipitation of solid phases, have been proven necessary to the understanding of the processes and closing the mass balance. As an example of micropollutant results, the ubiquitous beta-blocker atenolol is completely removed in the experiments, the removal occurring faster under more advanced redox conditions. This suggests that aquifers constitute a potentially efficient alternative water treatment for atenolol, especially if adequate redox conditions are promoted during recharge and long enough residence times are ensured. PMID:22115096

  16. Microcosm experiments to control anaerobic redox conditions when studying the fate of organic micropollutants in aquifer material

    NASA Astrophysics Data System (ADS)

    Barbieri, Manuela; Carrera, Jesús; Sanchez-Vila, Xavier; Ayora, Carlos; Cama, Jordi; Köck-Schulmeyer, Marianne; López de Alda, Miren; Barceló, Damià; Tobella Brunet, Joana; Hernández García, Marta

    2011-11-01

    The natural processes occurring in subsurface environments have proven to effectively remove a number of organic pollutants from water. The predominant redox conditions revealed to be one of the controlling factors. However, in the case of organic micropollutants the knowledge on this potential redox-dependent behavior is still limited. Motivated by managed aquifer recharge practices microcosm experiments involving aquifer material, settings potentially feasible in field applications, and organic micropollutants at environmental concentrations were carried out. Different anaerobic redox conditions were promoted and sustained in each set of microcosms by adding adequate quantities of electron donors and acceptors. Whereas denitrification and sulfate-reducing conditions are easily achieved and maintained, Fe- and Mn-reduction are strongly constrained by the slower dissolution of the solid phases commonly present in aquifers. The thorough description and numerical modeling of the evolution of the experiments, including major and trace solutes and dissolution/precipitation of solid phases, have been proven necessary to the understanding of the processes and closing the mass balance. As an example of micropollutant results, the ubiquitous beta-blocker atenolol is completely removed in the experiments, the removal occurring faster under more advanced redox conditions. This suggests that aquifers constitute a potentially efficient alternative water treatment for atenolol, especially if adequate redox conditions are promoted during recharge and long enough residence times are ensured.

  17. Effects of chronic γ-irradiation on the aquatic microbial microcosm: equi-dosimetric comparison with effects of heavy metals.

    PubMed

    Fuma, Shoichi; Kawaguchi, Isao; Kubota, Yoshihisa; Yoshida, Satoshi; Kawabata, Zen'ichiro; Polikarpov, Gennady G

    2012-02-01

    Effects of chronic γ-irradiation were investigated in the aquatic microcosm consisting of flagellate algae Euglena gracilis as producers, ciliate protozoa Tetrahymena thermophila as consumers and bacteria Escherichia coli as decomposers. At 1.1 Gy day(-1), no effects were observed. At 5.1 Gy day(-1), cell densities of E. coli showed a tendency to be lower than those of controls. At 9.7 and 24.7 Gy day(-1), population decrease was observed in E. coli. E. gracilis and T. thermophila died out after temporal population decrease and subsequent population increase in T. thermophila. It is likely that this temporal population increase was an indirect effect due to interspecies interactions. Effect dose rates of γ-rays were compared with effect concentrations of some metals using the radiochemoecological conceptual model and the effect index for microcosm. Comparison of these community-level effects data with environmental exposure data suggests that ionising radiation, gadolinium and dysprosium have low risks to affect aquatic microbial communities while manganese, nickel and copper have considerable risks. Effects of chronic irradiation were smaller than those of acute irradiation, and an acute to chronic ratio was calculated to be 28 by dividing an acute dose by chronic daily dose rate at which the effect index was 10%. This ratio would be useful for community-level extrapolation from acute to chronic radiation effects. PMID:21962482

  18. Influence of temperature and soil water content on bacterial, archaeal and denitrifying microbial communities in drained fen grassland soil microcosms.

    PubMed

    Stres, Blaz; Danevcic, Tjasa; Pal, Levin; Fuka, Mirna Mrkonjić; Resman, Lara; Leskovec, Simona; Hacin, Janez; Stopar, David; Mahne, Ivan; Mandic-Mulec, Ines

    2008-10-01

    In this study, microcosms were used to investigate the influence of temperature (4 and 28 degrees C) and water content (45% and 90% WHC) on microbial communities and activities in carbon-rich fen soil. Bacterial, archaeal and denitrifier community composition was assessed during incubation of microcosms for 12 weeks using terminal restriction fragment length polymorphism (T-RFLP) profiling of 16S rRNA and nitrous oxide reductase (nosZ) genes. In addition, microbial and denitrifier abundance, potential denitrification activity and production of greenhouse gases were measured. No detectable changes were observed in prokaryote or denitrifier abundance. In general, cumulatively after 12 weeks more carbon was respired at the higher temperature (3.7 mg CO(2) g(-1) soil), irrespective of the water content, whereas nitrous oxide production was greater under wet conditions (98-336 microg N(2)O g(-1) soil). After an initial lag phase, methane emissions (963 microg CH(4) g(-1) soil) were observed only under warm and wet conditions. T-RFLP analyses of bacterial 16S rRNA and nosZ genes revealed small or undetectable community changes in response to temperature and water content, suggesting that bacterial and denitrifying microbial communities are stable and do not respond significantly to seasonal changes in soil conditions. In contrast, archaeal microbial community structure was more dynamic and was strongly influenced by temperature. PMID:18710395

  19. The toxicity of a neem insecticide to populations of culicidae and other aquatic invertebrates as assessed in in situ microcosms.

    PubMed

    Scott, I M; Kaushik, N K

    2000-10-01

    Microcosm trials were conducted with the botanical insecticide Margosan-O(R) to assess the potential hazards of the product to aquatic organisms. Laboratory chronic bioassays with water from the treated microcosms were conducted to provide an estimate of the residual effect of Margosan-O. Results from chronic tests showed Margosan-O toxicity to be greater in the laboratory exposures than in situ with Culicidae larvae exposed to the same concentrations. Residue analyses of the active ingredient, azadirachtin, determined that it had a half-life of 36 to 48 h in water exposed to natural sunlight. Two applications of Margosan-O at the recommended application rate for pests did not harm aquatic invertebrates that are categorized as planktonic and filter feeding (Culex sp. and Daphnia sp.). However, the benthic invertebrate (Chironomus riparius) was affected by multiple applications of neem. These results show that the use of Margosan-O and possibly other neem extracts in or near aquatic environments could lead to disturbances in benthic populations and may cause decreases in numbers of organisms that are important in food web and nutrient cycling processes. PMID:10948283

  20. Intact and long-lasting repetition priming in amnesia.

    PubMed

    Cave, C B; Squire, L R

    1992-05-01

    In 2 experiments, we evaluated the ability of amnesic patients to exhibit long-lasting perceptual priming after a single exposure to pictures. Ss named pictures as quickly as possible on a single occasion, and later named the same pictures mixed with new pictures. In Experiment 1, amnesic patients exhibited fully intact priming effects lasting at least 7 days. In Experiment 2, the priming effect for both groups was shown to depend on both highly specific visual information and on less visual, more conceptual information. In contrast, recognition memory was severely impaired in the patients, as assessed by both accuracy and response time. The results provide the first report of a long-lasting priming effect in amnesic patients, based on a single encounter, which occurs as strongly in the patients as in normal Ss. Together with other recent findings, the results suggest that long-lasting priming and recognition memory depend on separate brain systems. PMID:1534352

  1. Intact Conceptual Priming in the Absence of Declarative Memory

    PubMed Central

    Levy, D.A.; Stark, C.E.L.; Squire, L.R.

    2009-01-01

    Priming is an unconscious (nondeclarative) form of memory whereby identification or production of an item is improved by an earlier encounter. It has been proposed that declarative memory and priming might be related—for example, that conceptual priming results in more fluent processing, thereby providing a basis for familiarity judgments. In two experiments, we assessed conceptual priming and recognition memory across a 5-min interval in 5 memory-impaired patients. All patients exhibited fully intact priming in tests of both free association (study tent; at test, provide an association to canvas) and category verification (study lemon; at test, decide: Is lemon a type of fruit?). Yet the 2 most severely amnesic patients performed at chance on matched tests of recognition memory. These findings count against the notion that conceptual priming provides feelings of familiarity that can support accurate recognition judgments. We suggest that priming is inaccessible to conscious awareness and does not influence declarative memory. PMID:15447639

  2. Semipermeability of the nuclear membrane in the intact cell.

    PubMed

    HARDING, C V; FELDHERR, C

    1959-07-20

    The osmotic properties of nuclei in intact cells were studied by injecting solutions into the cytoplasm of amphibian oocytes. Subsequent changes in nuclear volume were recorded photographically. The injection of solutions containing polyvinylpyrrolidone or bovine serum albumin caused changes in nuclear volume which were related to the colloid osmotic pressure of the solution injected. The concentration in which no significant nuclear volume change occurred (the isotonic range) was 1.0 to 1.5 per cent polyvinylpyrrolidone (2.0 to 3.75 x 10(-4)M). 2 per cent bovine serum albumin had no significant effect on nuclear volume, whereas 4 per cent caused a significant decrease. The significance of these findings is discussed in terms of the permeability characteristics of the nuclear membrane. PMID:13664918

  3. Simple Genome Editing of Rodent Intact Embryos by Electroporation

    PubMed Central

    Kaneko, Takehito; Mashimo, Tomoji

    2015-01-01

    The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) system is a powerful tool for genome editing in animals. Recently, new technology has been developed to genetically modify animals without using highly skilled techniques, such as pronuclear microinjection of endonucleases. Technique for animal knockout system by electroporation (TAKE) method is a simple and effective technology that produces knockout rats by introducing endonuclease mRNAs into intact embryos using electroporation. Using TAKE method and CRISPR/Cas system, the present study successfully produced knockout and knock-in mice and rats. The mice and rats derived from embryos electroporated with Cas9 mRNA, gRNA and single-stranded oligodeoxynucleotide (ssODN) comprised the edited targeted gene as a knockout (67% of mice and 88% of rats) or knock-in (both 33%). The TAKE method could be widely used as a powerful tool to produce genetically modified animals by genome editing. PMID:26556280

  4. Intact quasiparticles at an unconventional quantum critical point

    NASA Astrophysics Data System (ADS)

    Sutherland, M. L.; O'Farrell, E. C. T.; Toews, W. H.; Dunn, J.; Kuga, K.; Nakatsuji, S.; Machida, Y.; Izawa, K.; Hill, R. W.

    2015-07-01

    We report measurements of in-plane electrical and thermal transport properties in the limit T →0 near the unconventional quantum critical point in the heavy-fermion metal β -YbAlB4 . The high Kondo temperature TK≃200 K in this material allows us to probe transport extremely close to the critical point, at unusually small values of T /TK<5 ×10-4 . Here we find that the Wiedemann-Franz law is obeyed at the lowest temperatures, implying that the Landau quasiparticles remain intact in the critical region. At finite temperatures we observe a non-Fermi-liquid T -linear dependence of inelastic-scattering processes to energies lower than those previously accessed. These processes have a weaker temperature dependence than in comparable heavy fermion quantum critical systems, revealing a temperature scale of T ˜0.3 K which signals a sudden change in the character of the inelastic scattering.

  5. Calcium Activation Profile In Electrically Stimulated Intact Rat Heart Cells

    NASA Astrophysics Data System (ADS)

    Geerts, Hugo; Nuydens, Rony; Ver Donck, Luc; Nuyens, Roger; De Brabander, Marc; Borgers, Marcel

    1988-06-01

    Recent advances in fluorescent probe technology and image processing equipment have made available the measurement of calcium in living systems on a real-time basis. We present the use of the calcium indicator Fura-2 in intact normally stimulated rat heart cells for the spatial and dynamic measurement of the calcium excitation profile. After electric stimulation (1 Hz), the activation proceeds from the center of the myocyte toward the periphery. Within two frame times (80 ms), the whole cell is activated. The activation is slightly faster in the center of the cell than in the periphery. The mean recovery time is 200-400 ms. There is no difference along the cell's long axis. The effect of a beta-agonist and of a calcium antagonist is described.

  6. Ischaemic stroke with intact atrial septum--exclude arteriovenous malformations.

    PubMed

    Doering, Friederike; Eicken, Andreas; Hess, John

    2014-02-01

    A 44-year-old woman was referred to our centre for interventional cardiac catheterisation. The diagnostic work-up after a preceding ischaemic stroke led to the assumption of a patent foramen ovale due to a positive bubble study. Before the planned percutaneous closure of the patent foramen ovale, we performed a second bubble study, which showed an intact atrial septum. However, after two to three heart cycles bubbles could be detected in the left atrium, assuming a right-to-left shunt of an extracardiac origin most likely in the lung. We therefore performed cardiac catheterisation, yielding a pulmonary arteriovenous malformation in the lower lobe of the right lung. This was successfully closed interventionally by placing a Cook coil, as well as several plugs into the malformation and feeding vessels. PMID:23347820

  7. In vivo measurement of muscle output in intact Drosophila.

    PubMed

    Elliott, Christopher J H; Sparrow, John C

    2012-01-01

    We describe our methods for analysing muscle function in a whole intact small insect, taking advantage of a simple flexible optical beam to produce an inexpensive transducer with wide application. We review our previous data measuring the response to a single action potential driven muscle twitch to explore jumping behaviour in Drosophila melanogaster. In the fruitfly, where the sophisticated and powerful genetic toolbox is being widely employed to investigate neuromuscular function, we further demonstrate the use of the apparatus to analyse in detail, within whole flies, neuronal and muscle mutations affecting activation of muscle contraction in the jump muscle. We have now extended the use of the apparatus to record the muscle forces during larval and other aspects of adult locomotion. The robustness, simplicity and versatility of the apparatus are key to these measurements. PMID:22037247

  8. Final Technical Report: Optimization and Directed, Natural Evolution of Biologically-Mediated Chromate Reduction in Subsurface Soil Microcosms

    SciTech Connect

    Thompson, Dorothea K; Wickham, Gene S; Layton, Alice C

    2012-07-27

    The U.S. Department of Energy (DOE) is faced with the complex challenge of remediating or containing the various mixed wastes present in the subsurface environments of numerous DOE sites. The development of scientifically grounded strategies for the effective management and reclamation of these contaminated sites requires fundamental knowledge on the composition, dynamics, and metabolic potential of indigenous microbial communities, which are of primary importance in the fate and transport of heavy metals and radionuclides in subsurface environments. To date, the complex effect of environmental (both geochemical and biological) parameters on the bioremediative potential of subsurface microbial populations is only partially understood; this is primarily because the majority of microbial ecological studies have focused only on a qualitative analysis of subsurface microbial diversity, while the impact of quantitative changes in microbial communities as a function of environmental factors has been ignored. The project described here directly addresses the need for a more comprehensive, molecular understanding of how microbial growth and activity quantitatively relate to mineral and contaminant biotransformation (Science Element: Subsurface Microbial Ecology and Community, Notice DE-FG02-06ER06-12). The proposed study uses a truly novel combination of standard molecular phylogenetic analyses, rRNA-targeted fluorescence in situ hybridization, and mass spectrometry (MS)-based proteomics to investigate the biological response to experimentally controlled conditions and the concomitant effect on chromate reduction in situ. This response will be characterized in terms of microbial community structure (principally, population number and spatial distribution) and community proteome dynamics. Towards this overarching goal, we will (1) set up aerobic and anaerobic laboratory microcosms derived from subsurface soil collected from a chromate [Cr(VI)]-contaminated DOE site, and

  9. Zeta Potential in Intact Natural Carbonates at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Al-Mahrouqi, D.; Vinogradov, J.; Jackson, M.

    2015-12-01

    Measurements of zeta potential have been used to monitor subsurface flows in many natural brine systems. Numerous studies report zeta potentials in carbonates using crushed samples at low ionic strength and laboratory temperatures. However, natural brines have much higher salinity; moreover, temperatures are considerably higher in many subsurface settings. The variation of zeta potentials with temperature has not been examined in natural carbonates. We report zeta potential values interpreted from streaming potential measurements in two intact carbonate rock samples, saturated with artificial brines at elevated temperatures. We measure streaming potential using an experimental set-up that incorporates in-situ measurements of saturated rock conductivity, brine temperature, brine pH, brine electrical conductivity, pressure difference and voltage at temperatures up to 120oC. The streaming potential measurements are complemented with brine effluent studies. We find that the interpreted zeta potential is negative and decreases in magnitude with increasing temperature at low ionic strength (0.01M) and independent of temperature at high ionic strength (0.5M); consistent with published zeta potential in intact natural sandstones. The concentration of Ca2+ (main potential determining ion) also decreases with temperature at low ionic strength, but remains constant at high ionic strength. The temperature dependence of the zeta potential is consistent between two different natural carbonate samples and can be explained by the temperature dependence of pCa2+. We suggest that zeta potential of carbonate is independent of temperature or pH when pCa2+ remains constant. A linear variation of pH vs. pCa2+ is exhibited, at ambient and elevated temperatures, when pCa2+ is allowed to change with pH. This linear variation explains the numerous published data that shows apparent relationship between zeta potential of carbonates and pH.

  10. Isolation of intact sub-dermal secretory cavities from Eucalyptus

    PubMed Central

    2010-01-01

    Background The biosynthesis of plant natural products in sub-dermal secretory cavities is poorly understood at the molecular level, largely due to the difficulty of physically isolating these structures for study. Our aim was to develop a protocol for isolating live and intact sub-dermal secretory cavities, and to do this, we used leaves from three species of Eucalyptus with cavities that are relatively large and rich in essential oils. Results Leaves were digested using a variety of commercially available enzymes. A pectinase from Aspergillus niger was found to allow isolation of intact cavities after a relatively short incubation (12 h), with no visible artifacts from digestion and no loss of cellular integrity or cavity contents. Several measurements indicated the potential of the isolated cavities for further functional studies. First, the cavities were found to consume oxygen at a rate that is comparable to that estimated from leaf respiratory rates. Second, mRNA was extracted from cavities, and it was used to amplify a cDNA fragment with high similarity to that of a monoterpene synthase. Third, the contents of the cavity lumen were extracted, showing an unexpectedly low abundance of volatile essential oils and a sizeable amount of non-volatile material, which is contrary to the widely accepted role of secretory cavities as predominantly essential oil repositories. Conclusions The protocol described herein is likely to be adaptable to a range of Eucalyptus species with sub-dermal secretory cavities, and should find wide application in studies of the developmental and functional biology of these structures, and the biosynthesis of the plant natural products they contain. PMID:20807444

  11. Nanoplasmonic Quantitative Detection of Intact Viruses from Unprocessed Whole Blood

    PubMed Central

    Inci, Fatih; Tokel, Onur; Wang, ShuQi; Gurkan, Umut Atakan; Tasoglu, Savas; Kuritzkes, Daniel R.; Demirci, Utkan

    2013-01-01

    Infectious diseases such as HIV and Hepatitis B infection pose an omnipresent threat to global health. Reliable, fast, accurate and sensitive platforms that can be deployed at the point-of-care (POC) in multiple settings, such as airports and offices for detection of infectious pathogens are essential for the management of epidemics and possible biological attacks. To the best of our knowledge, no viral load technology adaptable to the POC settings exists today due to critical technical and biological challenges. Here, we present for the first time a broadly applicable technology for quantitative, nanoplasmonic-based intact virus detection at clinically relevant concentrations. The sensing platform is based on unique nanoplasmonic properties of nanoparticles utilizing immobilized antibodies to selectively capture rapidly evolving viral subtypes. We demonstrate the capture, detection and quantification of multiple HIV subtypes (A, B, C, D, E, G, and subtype panel) with high repeatability, sensitivity and specificity down to 98 ± 39 copies/mL (i.e., subtype D) using spiked whole blood samples and clinical discarded HIV-infected patient whole blood samples validated by the gold standard, i.e., RT-qPCR. This platform technology offers an assay time of 1 hour and 10 minutes (1 hour for capture, 10 minutes for detection and data analysis). The presented platform is also able to capture intact viruses at high efficiency using immuno-surface chemistry approaches directly from whole blood samples without any sample preprocessing steps such as spin-down or sorting. Evidence is presented showing the system to be accurate, repeatable and reliable. Additionally, the presented platform technology can be broadly adapted to detect other pathogens having reasonably well-described biomarkers by adapting the surface chemistry. Thus, this broadly applicable detection platform holds great promise to be implemented potentially at POC settings, hospital and primary care settings. PMID

  12. Hysteresis in the amount of colloids mobilized from intact cores of a fractured soil as a result of changes in the ionic strength of simulated rainfall

    NASA Astrophysics Data System (ADS)

    Mohanty, S.; Ryan, J. N.; Saiers, J. E.

    2010-12-01

    Understanding the mechanisms of colloid mobilization is essential to predicting the importance of colloid-facilitated transport of contaminants in subsurface environment. The mobilization of colloids increases with a decrease in the ionic strength of the pore water. Colloid mobilization is hysteretic in response to changes in ionic strength - the amount of colloids mobilized at a given ionic strength is not matched when the experiment is repeated following exposure to pore water of higher or lower ionic strengths. An exchange of pore water between the soil matrix and macropores is proposed to be the primary reason for the hysteresis of colloid mobilization during changes in ionic strength. The mobilization of colloids by pore water of a given ionic strength is either enhanced or inhibited by the slow release of matrix pore water of a lower or higher ionic strengths, respectively. This hypothesis was tested by conducting simulated rainfall experiments on undisturbed, intact cores of fractured soil (25.4 cm diameter, 15.2 cm depth) sampled from Oak Ridge National Laboratory, Tennessee. Rainfall of increasing, and then decreasing, ionic strength was applied to soil cores in successive events of 6 h of rainfall and an 18 h pause for each ionic strength. The ionic strength ranged from 0.01 to 10 mM as sodium chloride. Sodium bromide was included to provide a conservative tracer (Br-). Samples were collected from 19 ports in a hexagonal grid at the base of the soil core to identify regions of fast and slow flow attributed to macropore and matrix pathways. The samples were analyzed for concentrations of colloids (turbidity) and bromide (ion-selective electrode), conductivity, and pH. A flow-interruption method during bromide injection was employed to estimate the mass transfer rate of bromide between the soil macropores and matrix. Colloid concentrations, flow rates, and breakthrough times for bromide were found to be different for each port in the experiments at

  13. Dynamic changes in the structure of microbial communities in Baltic Sea coastal seawater microcosms modified by crude oil, shale oil or diesel fuel.

    PubMed

    Viggor, Signe; Juhanson, Jaanis; Jõesaar, Merike; Mitt, Mario; Truu, Jaak; Vedler, Eve; Heinaru, Ain

    2013-08-25

    The coastal waters of the Baltic Sea are constantly threatened by oil spills, due to the extensive transportation of oil products across the sea. To characterise the hydrocarbon-degrading bacterial community of this marine area, microcosm experiments on diesel fuel, crude oil and shale oil were performed. Analysis of these microcosms, using alkane monooxygenase (alkB) and 16S rRNA marker genes in PCR-DGGE experiments, demonstrated that substrate type and concentration strongly influence species composition and the occurrence of alkB genes in respective oil degrading bacterial communities. Gammaproteobacteria (particularly the genus Pseudomonas) and Alphaproteobacteria were dominant in all microcosms treated with oils. All alkB genes carried by bacterial isolates (40 strains), and 8 of the 11 major DGGE bands from the microcosms, had more than 95% sequence identity with the alkB genes of Pseudomonas fluorescens. However, the closest relatives of the majority of sequences (54 sequences from 79) of the alkB gene library from initially collected seawater DNA were Actinobacteria. alkB gene expression, induced by hexadecane, was recorded in isolated bacterial strains. Thus, complementary culture dependent and independent methods provided a more accurate picture about the complex seawater microbial communities of the Baltic Sea. PMID:23510642

  14. Planetary Resources and Astroecology. Planetary Microcosm Models of Asteroid and Meteorite Interiors: Electrolyte Solutions and Microbial Growth- Implications for Space Populations and Panspermia

    NASA Astrophysics Data System (ADS)

    Mautner, Michael N.

    2002-03-01

    Planetary microcosms were constructed using extracts from meteorites that simulate solutions in the pores of carbonaceous chondrites. The microcosms were found to support the growth of complex algal and microbial populations. Such astroecology experiments demonstrate how a diverse ecosystem could exist in fluids within asteroids, and in meteorites that land on aqueous planets. The microcosm solutions were obtained by extracting nutrient electrolytes under natural conditions from powders of the Allende (CV3) and Murchison (CM2) meteorites at low (0.02 g/ml) and high (10.0 g/ml) solid/solution ratios. The latter solutions contain >3 mol/L electrolytes and about 10 g/L organics, that simulate natural fluids in asteroids during aqueous alteration and in the pores of meteorites, which can help prebiotic synthesis and the survival of early microorganisms. These solutions and wet solids were in fact found to support complex self-sustaining microbial communities with populations of 4 × 105 algae and 6 × 106 bacteria and fungi for long periods (>8 months). The results show that planetary microcosms based on meteorites can: assay the fertilities of planetary materials; identify space bioresources; target astrobiology exploration; and model past and future space-based ecosystems. The results show that bioresources in the carbonaceous asteroids can sustain a biomass of 1018 kg, comprising 1032 microorganisms and a human population of 1014. The results also suggest that protoplanetary nebulae can support and disperse microorganisms and can be therefore effective environments for natural and directed panspermia.

  15. Survival, growth, and body residues of Hyalella azteca (Saussure) exposed to fipronil contaminated sediments from non-vegetated and vegetated microcosms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We assessed chronic effects of fipronil and metabolite contaminated sediments from non-vegetated and Thallia dealbata vegetated wetland microcosms on Hyalella azteca during wet and dry exposures. Mean sediment concentrations (ng g-1) ranged from 0.72-1.26, 0.01-0.69, 0.07-0.23, and 0.49-7.87 for fip...

  16. CHANGES IN ENANTIOMERIC FRACTIONS DURING MICROBIAL REDUCTIVE DECHLORINATION OF PCB132, PCB149, AND AROCLOR 1254 IN LAKE HARTWELL SEDIMENT MICROCOSMS

    EPA Science Inventory

    Enantioselectivity of microbial reductive dechlorination of chiral PCBs in sediments from Lake Hartwell, SC, was determined by microcosm studies and enantiomer-specific GC analysis. Sediments from two locations in the vicinity of the highest levels of PCB contamination were used...

  17. Dynamic Mechanical Properties of Intact Human Cervical Spine Ligaments

    PubMed Central

    Ivancic, Paul C.; Coe, Marcus P.; Ndu, Anthony B.; Tominaga, Yasuhiro; Carlson, Erik J.; Rubin, Wolfgang; (FH), Dipl-Ing; Panjabi, Manohar M.

    2009-01-01

    BACKGROUND CONTEXT Most previous studies have investigated ligaments mechanical properties at slow elongation rates of less than 25 mm/s. PURPOSE To determine the tensile mechanical properties, at a fast elongation rate, of intact human cervical anterior and posterior longitudinal, capsular, and interspinous and supraspinous ligaments, middle-third disc, and ligamentum flavum. STUDY DESIGN/SETTING In vitro biomechanical study. METHODS A total of 97 intact bone-ligament-bone specimens (C2–C3 to C7-T1) were prepared from six cervical spines (average age: 80.6 years, range, 71 to 92 years) and were elongated to complete rupture at an average (SD) peak rate of 723 (106) mm/s using a custom-built apparatus. Non-linear force vs. elongation curves were plotted and peak force, peak elongation, peak energy, and stiffness were statistically compared (P<0.05) among ligament. A mathematical model was developed to determine the quasi-static physiological ligament elongation. RESULTS Highest average peak force, up to 244.4 and 220.0 N in the ligamentum flavum and capsular ligament, respectively, were significantly greater than in the anterior longitudinal ligament and middle-third disc. Highest peak elongation reached 5.9 mm in the intraspinous and supraspinous ligaments, significantly greater than in the middle-third disc. Highest peak energy of 0.57 J was attained in the capsular ligament, significantly greater than in the anterior longitudinal ligament and middle-third disc. Average stiffness was generally greatest in the ligamentum flavum and least in the intraspinous and supraspinous ligaments. For all ligaments, peak elongation was greater than average physiological elongation computed using the mathematical model. CONCLUSIONS Comparison of the present results with previously reported data indicated that high speed elongation may cause cervical ligaments to fail at a higher peak force and smaller peak elongation and may be stiffer and absorb less energy, as compared to a

  18. Optimized Planning Target Volume for Intact Cervical Cancer

    SciTech Connect

    Khan, Alvin; Jensen, Lindsay G.; Sun Shuai; Song, William Y.; Yashar, Catheryn M.; Mundt, Arno J.; Zhang Fuquan; Jiang, Steve B.; Mell, Loren K.

    2012-08-01

    Purpose: To model interfraction clinical target volume (CTV) variation in patients with intact cervical cancer and design a planning target volume (PTV) that minimizes normal tissue dose while maximizing CTV coverage. Methods and Materials: We analyzed 50 patients undergoing external-beam radiotherapy for intact cervical cancer using daily online cone-beam computed tomography (CBCT). The CBCTs (n = 972) for each patient were rigidly registered to the planning CT. The CTV was delineated on the planning CT (CTV{sub 0}) and the set of CBCTs ({l_brace}CTV{sub 1}-CTV{sub 25}{r_brace}). Manual (n = 98) and automated (n = 668) landmarks were placed over the surface of CTV{sub 0} with reference to defined anatomic structures. Normal vectors were extended from each landmark, and the minimum length required for a given probability of encompassing CTV{sub 1}-CTV{sub 25} was computed. The resulting expansions were used to generate an optimized PTV. Results: The mean (SD; range) normal vector length to ensure 95% coverage was 4.3 mm (2.7 mm; 1-16 mm). The uniform expansion required to ensure 95% probability of CTV coverage was 13 mm. An anisotropic margin of 20 mm anteriorly and posteriorly and 10 mm superiorly, inferiorly, and laterally also would have ensured a 95% probability of CTV coverage. The volume of the 95% optimized PTV (1470 cm{sup 3}) was significantly lower than both the anisotropic PTV (2220 cm{sup 3}) and the uniformly expanded PTV (2110 cm{sup 3}) (p < 0.001). For a 95% probability of CTV coverage, normal lengths of 1-3 mm were found along the superior and lateral regions of CTV{sub 0}, 5-10 mm along the interfaces of CTV{sub 0} with the bladder and rectum, and 10-14 mm along the anterior surface of CTV{sub 0} at the level of the uterus. Conclusion: Optimizing PTV definition according to surface landmarking resulted in a high probability of CTV coverage with reduced PTV volumes. Our results provide data justifying planning margins to use in practice and

  19. Rapid isolation of intact, viable fetal cartilage models

    SciTech Connect

    Schmidt, R.R.; Chepenik, K.P.; Paynton, B.V.; Cotler, J.M.

    1982-04-01

    A rapid procedure is described for the isolation of viable, intact, femoral cartilage models (humeri and femora) obtained from pregnant rats on the 18th day of gestation. Viability of these models is demonstrated in an in vitro system where the incorporation of /sup 35/S-sulfate was linear with time of incubation and with numbers of cartilage models utilized. Treatment of cartilage models with ice-cold trichloroacetic acid and a boiling water bath prior to incubation with radiolabel, reduced the amount of radioactivity incorporated to 1.3% of that observed for models incubated by routine procedures. Furthermore, digestion of cartilage model homogenates with protease yielded a supernatant from which 51% to 57% of the radioactivity was precipitated as GAG. This method may also be used to isolate fetal cartilage models as early as the 16th day of gestation. with this system, specific biochemical parameters of mammalian fetal chondrogenesis may be surveyed in normally and abnormally developing fetal cartilage free of surrounding soft tissue.

  20. Intact alternation performance in high lethality suicide attempters.

    PubMed

    Keilp, John G; Wyatt, Gwinne; Gorlyn, Marianne; Oquendo, Maria A; Burke, Ainsley K; John Mann, J

    2014-09-30

    Suicide attempters often perform poorly on tasks linked to ventral prefrontal cortical (VPFC) function. Object Alternation (OA) - a VPFC probe - has not been used in these studies. In this study, currently depressed medication-free past suicide attempters whose most severe attempt was of high (n=31) vs. low (n=64) lethality, 114 medication-free depressed non-attempters, and 86 non-patients completed a computerized OA task. Participants also completed comparison tasks assessing the discriminant validity of OA (Wisconsin Card Sort), its concurrent validity relative to tasks associated with past attempt status (computerized Stroop task, Buschke Selective Reminding Test), and its construct validity as a VPFC measure (Go-No Go and Iowa Gambling Task). Against expectations, high lethality suicide attempters - the majority of whom used non-violent methods in their attempts with some planning - outperformed other depressed groups on OA, with no group differences observed on Wisconsin Card Sort. Despite intact performance on OA, past attempters exhibited deficits on the Stroop and Buschke. OA performance was associated with performance on Go-No Go and Iowa Gambling, confirming that OA measures a similar construct. VPFC dysfunction may not be a characteristic of all suicide attempters, especially those who make more carefully planned, non-violent - though potentially lethal - attempts. PMID:24878299

  1. Action perception is intact in autism spectrum disorder.

    PubMed

    Cusack, James P; Williams, Justin H G; Neri, Peter

    2015-02-01

    Autistic traits span a wide spectrum of behavioral departures from typical function. Despite the heterogeneous nature of autism spectrum disorder (ASD), there have been attempts at formulating unified theoretical accounts of the associated impairments in social cognition. A class of prominent theories capitalizes on the link between social interaction and visual perception: effective interaction with others often relies on discrimination of subtle nonverbal cues. It has been proposed that individuals with ASD may rely on poorer perceptual representations of other people's actions as returned by dysfunctional visual circuitry and that this, in turn, may lead to less effective interpretation of those actions for social behavior. It remains unclear whether such perceptual deficits exist in ASD: the evidence currently available is limited to specific aspects of action recognition, and the reported deficits are often attributable to cognitive factors that may not be strictly visual (e.g., attention). We present results from an exhaustive set of measurements spanning the entire action processing hierarchy, from motion detection to action interpretation, designed to factor out effects that are not selectively relevant to this function. Our results demonstrate that the ASD perceptual system returns functionally intact signals for interpreting other people's actions adequately; these signals can be accessed effectively when autistic individuals are prompted and motivated to do so under controlled conditions. However, they may fail to exploit them adequately during real-life social interactions. PMID:25653346

  2. Action Perception Is Intact in Autism Spectrum Disorder

    PubMed Central

    Williams, Justin H.G.; Neri, Peter

    2015-01-01

    Autistic traits span a wide spectrum of behavioral departures from typical function. Despite the heterogeneous nature of autism spectrum disorder (ASD), there have been attempts at formulating unified theoretical accounts of the associated impairments in social cognition. A class of prominent theories capitalizes on the link between social interaction and visual perception: effective interaction with others often relies on discrimination of subtle nonverbal cues. It has been proposed that individuals with ASD may rely on poorer perceptual representations of other people's actions as returned by dysfunctional visual circuitry and that this, in turn, may lead to less effective interpretation of those actions for social behavior. It remains unclear whether such perceptual deficits exist in ASD: the evidence currently available is limited to specific aspects of action recognition, and the reported deficits are often attributable to cognitive factors that may not be strictly visual (e.g., attention). We present results from an exhaustive set of measurements spanning the entire action processing hierarchy, from motion detection to action interpretation, designed to factor out effects that are not selectively relevant to this function. Our results demonstrate that the ASD perceptual system returns functionally intact signals for interpreting other people's actions adequately; these signals can be accessed effectively when autistic individuals are prompted and motivated to do so under controlled conditions. However, they may fail to exploit them adequately during real-life social interactions. PMID:25653346

  3. Spontaneous postpartum rupture of an intact uterus: a case report.

    PubMed

    Mavromatidis, George; Karavas, George; Margioula-Siarkou, Chrysoula; Petousis, Stamatios; Kalogiannidis, Ioannis; Mamopoulos, Apostolos; Rousso, David

    2015-01-01

    Rupture of uterus is an obstetrical complication characterized by a breach in the uterine wall and the overlying serosa. We report an unusual case of spontaneous rupture of an unscarred uterus in a 33-year-old woman, a day after her third successful vaginal delivery. A 33-year-old pregnant woman, gravid 3, para 3, was referred to our department at 39 gestational week because of rupture of membranes. Despite tocolysis administration, her pregnancy was delivered vaginally after 2 days, giving birth to a male neonate of 3,020 g with normal Apgar scores at first and fifth minute. Her uterus was intact and gynecological examination after delivery was normal without any potential signs or symptoms of pathology. However, the day following her labor, patient complained of left iliac fossa pain. Her blood tests revealed a CRP value at 27.6 mg/L, whereas the X-rays revealed an extensive impacted fecal mass in the colon. MRI revealed that the left lower myometrial part of the uterus was depicted abrupt, with simultaneous presence of hemorrhagic stuff. The decision of laparotomy was therefore made in order to further evaluate rupture of uterus and properly treat patient. And subtotal hysterectomy was performed. Postoperative follow-up period was not characterized by any complications and patient was finally discharged 4 days after hysterectomy. PMID:25368704

  4. Lipidation of intact proteins produces highly immunogenic vaccine candidates.

    PubMed

    Zeng, Weiguang; Eriksson, Emily M; Lew, Andrew; Jackson, David C

    2011-01-01

    In this study we investigate the feasibility of generating self-adjuvanting vaccines capable of inducing high titre antibody responses following the covalent attachment of the TLR2 agonist Pam(2)Cys to intact proteins. Three Pam(2)Cys-based lipid moieties were prepared which contain a solubilising spacer composed of either lysine residues or polyethyleneglycol. A model protein, hen egg white lysozyme (HEL), was lipidated individually with each of these lipid modules and the immunogenicity of the lipidated species studied in mice by measuring antibody responses. We found that lipidated HEL elicited antibodies which is much stronger than the responses obtained when the HEL was administered in Freund's adjuvant or in Alum. Little or no antibody was elicited by the lipidated HEL in CD4 T cell-deficient mice indicating that the antibody response is T cell dependent. Furthermore, the lipidated protein elicited similar antibody responses in two different strains of mice indicating that sufficient helper T cell epitopes are available to enable antibody production across the histocompatability barrier. In a similar way, lipidated bovine insulin was found to be highly immunogenic in mice despite the largely conserved sequences of bovine and murine insulin. The results provide evidence that lipidation of proteins provides a simple and safe method for the manufacture of soluble self-adjuvanting protein-based vaccines. PMID:21056473

  5. Some Factors Regulating Auxin Translocation in Intact Bean Seedlings 1

    PubMed Central

    Long, John; Basler, Eddie

    1973-01-01

    Several factors which influence the translocation patterns of stem-injected indoleacetic acid, 2,4-dichlorophenoxyacetic acid, and 2,4,5-trichlorophenoxyacetic acid in bean seedlings (Phaseolus vulgaris L. cv. Stringless Greenpod) were characterized. The acropetal translocation of auxin from the site of injection is markedly sensitive to concentration in the range of 1.0 to 5.0 micrograms per plant. The antiauxin p-chlorophenoxyisobutyric acid enhanced translocation of 2,4,5-trichlorophenoxyacetic acid to the growing shoots and primary leaves. Translocation to the roots was unaffected by p-chlorophenoxyisobutyric acid while leaching of 2,4,5-trichlorophenoxyacetic acid into the nutrient solution was enhanced slightly. Steam girdling experiments revealed that translocation to the primary leaves was in the xylem. The protein synthesis inhibitor, cycloheximide, inhibited accumulation of 2,4,5-trichlorophenoxyacetic acid in young shoots, epicotyls, and roots and enhanced accumulation in the primary leaves. The relative exchangeability of auxin between xylem and phloem is discussed in terms of regulation of auxin movements in intact bean seedlings. Images PMID:16658273

  6. True navigation in migrating gulls requires intact olfactory nerves.

    PubMed

    Wikelski, Martin; Arriero, Elena; Gagliardo, Anna; Holland, Richard A; Huttunen, Markku J; Juvaste, Risto; Mueller, Inge; Tertitski, Grigori; Thorup, Kasper; Wild, Martin; Alanko, Markku; Bairlein, Franz; Cherenkov, Alexander; Cameron, Alison; Flatz, Reinhard; Hannila, Juhani; Hüppop, Ommo; Kangasniemi, Markku; Kranstauber, Bart; Penttinen, Maija-Liisa; Safi, Kamran; Semashko, Vladimir; Schmid, Heidi; Wistbacka, Ralf

    2015-01-01

    During migratory journeys, birds may become displaced from their normal migratory route. Experimental evidence has shown that adult birds can correct for such displacements and return to their goal. However, the nature of the cues used by migratory birds to perform long distance navigation is still debated. In this experiment we subjected adult lesser black-backed gulls migrating from their Finnish/Russian breeding grounds (from >60°N) to Africa (to < 5°N) to sensory manipulation, to determine the sensory systems required for navigation. We translocated birds westward (1080 km) or eastward (885 km) to simulate natural navigational challenges. When translocated westwards and outside their migratory corridor birds with olfactory nerve section kept a clear directional preference (southerly) but were unable to compensate for the displacement, while intact birds and gulls with the ophthalmic branch of the trigeminal nerve sectioned oriented towards their population-specific migratory corridor. Thus, air-borne olfactory information seems to be important for migrating gulls to navigate successfully in some circumstances. PMID:26597351

  7. Hypoplastic left heart syndrome with intact atrial septum: case report

    PubMed Central

    Cester, Maddalena; Nanhorngue, Kimta; Pascoli, Irene; Garofano, Greta; Surico, Nicola; Paternoster, Delia Maria

    2007-01-01

    Summary Objectives Hypoplastic left heart syndrome (HLHS) with an intact atrial septum (IAS) is a rare finding, reported in only 1% of pathologic specimens with hypoplasia of the aortic tract complex. In newborns with left heart obstruction, the existence of an interatrial communication is very important for oxygenated blood to be distributed to the body and to prevent pulmonary congestion. The ability to predict prenatally restriction of the atrial defect may allow earlier surgery to be planned. Methods We report a case of prenatal diagnosis of HLHS with a complete premature closure of the foramen ovale that was not detected by prenatal echocardiography. Results and conclusion The management of neonates with HLHS in the first days of life is crucial to the results of the first stage of the Norwood procedure. We suggest that delivery of the mother close to surgical centre and avoiding neonatal transfer improve the results, but stabilisation with prostaglandins and balancing of the systemic and pulmonary resistances are also important. A restrictive or closed atrial septal defect may contribute to haemodynamic instability in the first days of life. The ability to predict this complication prenatally may help in the immediate postnatal management of the affected infant. PMID:22470823

  8. Structure of the intact ATM/Tel1 kinase

    PubMed Central

    Wang, Xuejuan; Chu, Huanyu; Lv, Mengjuan; Zhang, Zhihui; Qiu, Shuwan; Liu, Haiyan; Shen, Xuetong; Wang, Weiwu; Cai, Gang

    2016-01-01

    The ataxia-telangiectasia mutated (ATM) protein is an apical kinase that orchestrates the multifaceted DNA-damage response. Normally, ATM kinase is in an inactive, homodimer form and is transformed into monomers upon activation. Besides a conserved kinase domain at the C terminus, ATM contains three other structural modules, referred to as FAT, FATC and N-terminal helical solenoid. Here we report the first cryo-EM structure of ATM kinase, which is an intact homodimeric ATM/Tel1 from Schizosaccharomyces pombe. We show that two monomers directly contact head-to-head through the FAT and kinase domains. The tandem N-terminal helical solenoid tightly packs against the FAT and kinase domains. The structure suggests that ATM/Tel1 dimer interface and the consecutive HEAT repeats inhibit the binding of kinase substrates and regulators by steric hindrance. Our study provides a structural framework for understanding the mechanisms of ATM/Tel1 regulation as well as the development of new therapeutic agents. PMID:27229179

  9. Genetic disruptions of Drosophila Pavlovian learning leave extinction learning intact.

    PubMed

    Qin, H; Dubnau, J

    2010-03-01

    Individuals who experience traumatic events may develop persistent posttraumatic stress disorder. Patients with this disorder are commonly treated with exposure therapy, which has had limited long-term success. In experimental neurobiology, fear extinction is a model for exposure therapy. In this behavioral paradigm, animals are repeatedly exposed in a safe environment to the fearful stimulus, which leads to greatly reduced fear. Studying animal models of extinction already has lead to better therapeutic strategies and development of new candidate drugs. Lack of a powerful genetic model of extinction, however, has limited progress in identifying underlying molecular and genetic factors. In this study, we established a robust behavioral paradigm to study the short-term effect (acquisition) of extinction in Drosophila melanogaster. We focused on the extinction of olfactory aversive 1-day memory with a task that has been the main workhorse for genetics of memory in flies. Using this paradigm, we show that extinction can inhibit each of two genetically distinct forms of consolidated memory. We then used a series of single-gene mutants with known impact on associative learning to examine the effects on extinction. We find that extinction is intact in each of these mutants, suggesting that extinction learning relies on different molecular mechanisms than does Pavlovian learning. PMID:20015341

  10. Stress dependence of permeability of intact and fractured shale cores.

    NASA Astrophysics Data System (ADS)

    van Noort, Reinier; Yarushina, Viktoriya

    2016-04-01

    Whether a shale acts as a caprock, source rock, or reservoir, understanding fluid flow through shale is of major importance for understanding fluid flow in geological systems. Because of the low permeability of shale, flow is thought to be largely confined to fractures and similar features. In fracking operations, fractures are induced specifically to allow for hydrocarbon exploration. We have constructed an experimental setup to measure core permeabilities, using constant flow or a transient pulse. In this setup, we have measured the permeability of intact and fractured shale core samples, using either water or supercritical CO2 as the transporting fluid. Our measurements show decreasing permeability with increasing confining pressure, mainly due to time-dependent creep. Furthermore, our measurements show that for a simple splitting fracture, time-dependent creep will also eliminate any significant effect of this fracture on permeability. This effect of confinement on fracture permeability can have important implications regarding the effects of fracturing on shale permeability, and hence for operations depending on that.

  11. Bryostatins activate protein kinase C in intact human platelets

    SciTech Connect

    Smith, J.B.; Tallant, E.A.; Pettit, G.R.; Wallace, R.W.

    1986-05-01

    Bryostatins, macrocyclic lactones isolated from a marine bryozoan, have antineoplastic activity in the P388 lymphocytic leukemia system. These compounds also stimulate growth in Swiss 3T3 cells, induce secretion in leukocytes, inhibit phorbol dibutyrate binding to a high affinity receptor, and activate the C-kinase in vitro. In human platelets, phorbol esters induce aggregation and activate protein kinase C, resulting in phosphorylation of a 47K protein and the 20K myosin light chain. The authors now show that bryostatin 7 (B-7) triggers platelet aggregation to the same rate and extent as phorbol 12-myristate 13-acetate (PMA). B-7 also causes the in vivo activation of the C-kinase, resulting in phosphorylation of both the 47K and the 20K proteins; the time courses and dose-responses of these B-7-induced phosphorylations were similar to those found with PMA. In addition, B-7 increases the level of /sup 32/P-incorporation into the platelet polyphosphoinositides, which also occurs in response to PMA. Bryostatin 3 (B-3), which has been shown to be much less potent than B-7 in mimicking other PMA effects, was much less effective than PMA or B-7 in inducing platelet aggregation and in stimulating /sup 32/P-incorporation into both proteins and the phosphoinositides. These results demonstrate that, intact human platelets, bryostatins mimic the phorbol esters tumor promoters and directly activate protein kinase C.

  12. Structure of the intact ATM/Tel1 kinase

    NASA Astrophysics Data System (ADS)

    Wang, Xuejuan; Chu, Huanyu; Lv, Mengjuan; Zhang, Zhihui; Qiu, Shuwan; Liu, Haiyan; Shen, Xuetong; Wang, Weiwu; Cai, Gang

    2016-05-01

    The ataxia-telangiectasia mutated (ATM) protein is an apical kinase that orchestrates the multifaceted DNA-damage response. Normally, ATM kinase is in an inactive, homodimer form and is transformed into monomers upon activation. Besides a conserved kinase domain at the C terminus, ATM contains three other structural modules, referred to as FAT, FATC and N-terminal helical solenoid. Here we report the first cryo-EM structure of ATM kinase, which is an intact homodimeric ATM/Tel1 from Schizosaccharomyces pombe. We show that two monomers directly contact head-to-head through the FAT and kinase domains. The tandem N-terminal helical solenoid tightly packs against the FAT and kinase domains. The structure suggests that ATM/Tel1 dimer interface and the consecutive HEAT repeats inhibit the binding of kinase substrates and regulators by steric hindrance. Our study provides a structural framework for understanding the mechanisms of ATM/Tel1 regulation as well as the development of new therapeutic agents.

  13. True navigation in migrating gulls requires intact olfactory nerves

    PubMed Central

    Wikelski, Martin; Arriero, Elena; Gagliardo, Anna; Holland, Richard A.; Huttunen, Markku J.; Juvaste, Risto; Mueller, Inge; Tertitski, Grigori; Thorup, Kasper; Wild, Martin; Alanko, Markku; Bairlein, Franz; Cherenkov, Alexander; Cameron, Alison; Flatz, Reinhard; Hannila, Juhani; Hüppop, Ommo; Kangasniemi, Markku; Kranstauber, Bart; Penttinen, Maija-Liisa; Safi, Kamran; Semashko, Vladimir; Schmid, Heidi; Wistbacka, Ralf

    2015-01-01

    During migratory journeys, birds may become displaced from their normal migratory route. Experimental evidence has shown that adult birds can correct for such displacements and return to their goal. However, the nature of the cues used by migratory birds to perform long distance navigation is still debated. In this experiment we subjected adult lesser black-backed gulls migrating from their Finnish/Russian breeding grounds (from >60°N) to Africa (to < 5°N) to sensory manipulation, to determine the sensory systems required for navigation. We translocated birds westward (1080 km) or eastward (885 km) to simulate natural navigational challenges. When translocated westwards and outside their migratory corridor birds with olfactory nerve section kept a clear directional preference (southerly) but were unable to compensate for the displacement, while intact birds and gulls with the ophthalmic branch of the trigeminal nerve sectioned oriented towards their population-specific migratory corridor. Thus, air-borne olfactory information seems to be important for migrating gulls to navigate successfully in some circumstances. PMID:26597351

  14. Structure of the intact ATM/Tel1 kinase.

    PubMed

    Wang, Xuejuan; Chu, Huanyu; Lv, Mengjuan; Zhang, Zhihui; Qiu, Shuwan; Liu, Haiyan; Shen, Xuetong; Wang, Weiwu; Cai, Gang

    2016-01-01

    The ataxia-telangiectasia mutated (ATM) protein is an apical kinase that orchestrates the multifaceted DNA-damage response. Normally, ATM kinase is in an inactive, homodimer form and is transformed into monomers upon activation. Besides a conserved kinase domain at the C terminus, ATM contains three other structural modules, referred to as FAT, FATC and N-terminal helical solenoid. Here we report the first cryo-EM structure of ATM kinase, which is an intact homodimeric ATM/Tel1 from Schizosaccharomyces pombe. We show that two monomers directly contact head-to-head through the FAT and kinase domains. The tandem N-terminal helical solenoid tightly packs against the FAT and kinase domains. The structure suggests that ATM/Tel1 dimer interface and the consecutive HEAT repeats inhibit the binding of kinase substrates and regulators by steric hindrance. Our study provides a structural framework for understanding the mechanisms of ATM/Tel1 regulation as well as the development of new therapeutic agents. PMID:27229179

  15. Basic Timing Abilities Stay Intact in Patients with Musician's Dystonia

    PubMed Central

    van der Steen, M. C.; van Vugt, Floris T.; Keller, Peter E.; Altenmüller, Eckart

    2014-01-01

    Task-specific focal dystonia is a movement disorder that is characterized by the loss of voluntary motor control in extensively trained movements. Musician's dystonia is a type of task-specific dystonia that is elicited in professional musicians during instrumental playing. The disorder has been associated with deficits in timing. In order to test the hypothesis that basic timing abilities are affected by musician's dystonia, we investigated a group of patients (N = 15) and a matched control group (N = 15) on a battery of sensory and sensorimotor synchronization tasks. Results did not show any deficits in auditory-motor processing for patients relative to controls. Both groups benefited from a pacing sequence that adapted to their timing (in a sensorimotor synchronization task at a stable tempo). In a purely perceptual task, both groups were able to detect a misaligned metronome when it was late rather than early relative to a musical beat. Overall, the results suggest that basic timing abilities stay intact in patients with musician's dystonia. This supports the idea that musician's dystonia is a highly task-specific movement disorder in which patients are mostly impaired in tasks closely related to the demands of actually playing their instrument. PMID:24667273

  16. Adolescent Segond fracture with an intact anterior cruciate ligament.

    PubMed

    Reddy, Deepak; Alexander, Reginald; Hussain, Waqas M; Leland, J Martin

    2012-07-01

    Segond fractures, or avulsion fractures of the proximal lateral tibial plateau, have been well documented and studied since their original description in 1878. Segond fractures have a widely recognized pathognomonic association with anterior cruciate ligament (ACL) injuries and often prompt orthopedic surgeons to consider reconstruction following radiographic and clinical evaluation. Adolescent patients are particularly vulnerable to these fractures due to the relative weakness of their physeal growth plates compared with the strength of their accompanying ligamentous structures. This article describes a case of a 13-year-old boy who sustained a Segond fracture that was not coupled with an ACL avulsion or tear. The patient sustained a twisting injury to his knee. He presented to the emergency room with an effusion and radiographic findings consistent with a Segond fracture. On follow-up examination 1 week after injury, the ACL was intact. The patient was followed for 5 months of conservative treatment. At final follow-up, the patient had reestablished his previous level of activity. This article describes the history, physical examination, and radiographic findings necessary to care for patients who present with a Segond fracture. Although considered pathognomonic for an associated ACL injury, this article describes a Segond fracture that occurred in isolation. PMID:22784911

  17. Basic timing abilities stay intact in patients with musician's dystonia.

    PubMed

    van der Steen, M C; van Vugt, Floris T; Keller, Peter E; Altenmüller, Eckart

    2014-01-01

    Task-specific focal dystonia is a movement disorder that is characterized by the loss of voluntary motor control in extensively trained movements. Musician's dystonia is a type of task-specific dystonia that is elicited in professional musicians during instrumental playing. The disorder has been associated with deficits in timing. In order to test the hypothesis that basic timing abilities are affected by musician's dystonia, we investigated a group of patients (N = 15) and a matched control group (N = 15) on a battery of sensory and sensorimotor synchronization tasks. Results did not show any deficits in auditory-motor processing for patients relative to controls. Both groups benefited from a pacing sequence that adapted to their timing (in a sensorimotor synchronization task at a stable tempo). In a purely perceptual task, both groups were able to detect a misaligned metronome when it was late rather than early relative to a musical beat. Overall, the results suggest that basic timing abilities stay intact in patients with musician's dystonia. This supports the idea that musician's dystonia is a highly task-specific movement disorder in which patients are mostly impaired in tasks closely related to the demands of actually playing their instrument. PMID:24667273

  18. Flux profiling of photosynthetic carbon metabolism in intact plants.

    PubMed

    Heise, Robert; Arrivault, Stéphanie; Szecowka, Marek; Tohge, Takayuki; Nunes-Nesi, Adriano; Stitt, Mark; Nikoloski, Zoran; Fernie, Alisdair R

    2014-08-01

    Flux analysis has been carried out in plants for decades, but technical innovations are now enabling it to be carried out in photosynthetic tissues in a more precise fashion with respect to the number of metabolites measured. Here we describe a protocol, using gas chromatography (GC)- and liquid chromatography (LC)-mass spectrometry (MS), to resolve intracellular fluxes of the central carbon metabolism in illuminated intact Arabidopsis thaliana rosettes using the time course of the unlabeled fractions in 40 major constituents of the metabolome after switching to (13)CO2. We additionally simplify modeling assumptions, specifically to cope with the presence of multiple cellular compartments. We summarize all steps in this 8-10-week-long process, including setting up the chamber; harvesting; liquid extraction and subsequent handling of sample plant material to chemical derivatization procedures such as silylation and methoxymation (necessary for gas chromatography only); choosing instrumentation settings and evaluating the resultant chromatogram in terms of both unlabeled and labeled peaks. Furthermore, we describe how quantitative insights can be gained by estimating both benchmark and previously unknown fluxes from collected data sets. PMID:24992096

  19. Measurement of the Mechanical Properties of Intact Collagen Fibrils

    NASA Astrophysics Data System (ADS)

    Mercedes, H.; Heim, A.; Matthews, W. G.; Koob, T.

    2006-03-01

    Motivated by the genetic disorder Ehlers-Danlos syndrome (EDS), in which proper collagen synthesis is interrupted, we are investigating the structural and mechanical properties of collagen fibrils. The fibrous glycoprotein collagen is the most abundant protein found in the human body and plays a key role in the extracellular matrix of the connective tissue, the properties of which are altered in EDS. We have selected as our model system the collagen fibrils of the sea cucumber dermis, a naturally mutable tissue. This system allows us to work with native fibrils which have their proteoglycan complement intact, something that is not possible with reconstituted mammalian collagen fibrils. Using atomic force microscopy, we measure, as a function of the concentration of divalent cations, the fibril diameter, its response to force loading, and the changes in its rigidity. Through these experiments, we will shed light on the mechanisms which control the properties of the sea cucumber dermis and hope to help explain the altered connective tissue extracellular matrix properties associated with EDS.

  20. Activation and deactivation of vibronic channels in intact phycocyanin rods

    NASA Astrophysics Data System (ADS)

    Nganou, C.; David, L.; Meinke, R.; Adir, N.; Maultzsch, J.; Mkandawire, M.; Pouhè, D.; Thomsen, C.

    2014-02-01

    We investigated the excitation modes of the light-harvesting protein phycocyanin (PC) from Thermosynechococcus vulcanus in the crystalline state using UV and near-infrared Raman spectroscopy. The spectra revealed the absence of a hydrogen out-of-plane wagging (HOOP) mode in the PC trimer, which suggests that the HOOP mode is activated in the intact PC rod, while it is not active in the PC trimer. Furthermore, in the PC trimer an intense mode at 984 cm-1 is assigned to the C-C stretching vibration while the mode at 454 cm-1 is likely due to ethyl group torsion. In contrast, in the similar chromophore phytochromobilin the C5,10,15-D wag mode at 622 cm-1 does not come from a downshift of the HOOP. Additionally, the absence of modes between 1200 and 1300 cm-1 rules out functional monomerization. A correlation between phycocyanobilin (PCB) and phycoerythrobilin (PEB) suggests that the PCB cofactors of the PC trimer appear in a conformation similar to that of PEB. The conformation of the PC rod is consistent with that of the allophycocyanin (APC) trimer, and thus excitonic flow is facilitated between these two independent light-harvesting compounds. This excitonic flow from the PC rod to APC appears to be modulated by the vibration channels during HOOP wagging, C = C stretching, and the N-H rocking in-plan vibration.

  1. Intact implicit processing of facial threat cues in schizophrenia.

    PubMed

    Shasteen, Jonathon R; Pinkham, Amy E; Kelsven, Skylar; Ludwig, Kelsey; Payne, B Keith; Penn, David L

    2016-01-01

    An emerging body of research suggests that people with schizophrenia retain the ability to implicitly perceive facial affect, despite well-documented difficulty explicitly identifying emotional expressions. It remains unclear, however, whether such functional implicit processing extends beyond emotion to other socially relevant facial cues. Here, we constructed two novel versions of the Affect Misattribution Procedure, a paradigm in which affective responses to primes are projected onto neutral targets. The first version included three face primes previously validated to elicit varying inferences of threat from healthy individuals via emotion-independent structural modification (e.g., nose and eye size). The second version included the threat-relevant emotional primes of angry, neutral, and happy faces. Data from 126 participants with schizophrenia and 84 healthy controls revealed that although performing more poorly on an assessment of explicit emotion recognition, patients showed normative implicit threat processing for both non-emotional and emotional facial cues. Collectively, these results support recent hypotheses postulating that the initial perception of salient facial information remains intact in schizophrenia, but that deficits arise at subsequent stages of contextual integration and appraisal. Such a breakdown in the stream of face processing has important implications for mechanistic models of social cognitive impairment in schizophrenia and treatment strategies aiming to improve functional outcome. PMID:26673971

  2. Stimulation of the cerebral cortex in the intact human subject

    NASA Astrophysics Data System (ADS)

    Merton, P. A.; Morton, H. B.

    1980-05-01

    One of the most fertile methods of investigating the brain is to stimulate a part of it electrically and observe the results. So far, however, use of the method in man has been restricted by the necessity of opening the skull surgically to apply the electrodes. Much could be done, both with healthy subjects and with neurological patients, if it were feasible to stimulate through electrodes on the scalp, although the localization of the stimulus on the cortex will always be much less sharp than with electrodes on the brain surface. In an intact man, however, the brain is protected from electricity by the skull and by the scalp, both of which normally offer considerable resistance. Furthermore, the cerebral cortex does not have a particularly low electrical threshold. It is probably for these reasons (despite an occasional contrary claim1) that attempts to stimulate the brain by applying stimuli from conventional stimulators to the scalp have been stopped by pain or have otherwise failed. These obstacles have now begun to yield. Recently, it was found that, on stimulating muscles in the human hand2 without any special preparation of the skin, the effective resistance fell to low values if brief but very high voltage shocks were used. Applying the same technique to the head, it has now proved possible at the first attempt to stimulate two areas of the human cortex, without undue discomfort.

  3. Use of Fixed-Film Bioreactors, in Situ Microcosms, and Molecular Biological Analyses to Evaluate Bioremediation of Chlorinated Benzenes By Indigenous Bacteria and a Bioaugmented Dechlorinating Consortium

    NASA Astrophysics Data System (ADS)

    Lorah, M. M.; Teunis, J. A.

    2014-12-01

    Evaluation of bioremediation is complicated by contaminant mixtures, high concentrations, variable site conditions, and multiple possible degradation pathways. In this study, fixed-film bioreactor experiments, in situ microcosms, and microbial analyses were utilized to evaluate both anaerobic and aerobic biodegradation processes for tri- and dichlorobenzene isomers, monochlorobenzene, and benzene in a wetland. Biofilm-based bioreactors provide a robust assessment tool because of their typically high degree of stability, even with major and repeated perturbations. Two bioreactor units seeded with an anaerobic dechlorinating consortium (WBC-2) and one unit seeded only with bacteria indigenous to the site were operated under flow-through conditions to compare biougmentation and natural attenuation. Electron donor levels were varied to fluctuate between anaerobic and aerobic conditions, and inflow concentrations of total chlorobenzenes were transitioned from 1-10 mg/L to 50-100 mg/L. Biodegradation resulted in removal efficiencies of 80 to 99 percent for the different compounds and inflow concentrations. Degradation efficiency in the native bioreactor was not impacted by cycling between anaerobic and aerobic conditions, although removal rates for monochlorobenzene and benzene increased under aerobic conditions. In situ microcosms were incubated below the wetland surface in sets of 3 treatments—unamended, biostimulated (lactate addition), and bioaugmented (WBC-2 and lactate). Additional treatment sets contained 13C-labeled contaminants to monitor for production of 13C-containing carbon dioxide and cellular material. Microcosm results verified that WBC-2 bioaugmentation can enhance biodegradation, with complete mineralization of chlorobenzene and benzene in bioaugmented and native treatments. Microbial analyses using QuantArrayTM for functional and taxonomic genes indicated potential for co-occurrence of anaerobic and aerobic biodegradation. Compared to the unamended

  4. Microbial community characterization and functional gene quantification in RDX-degrading microcosms derived from sediment and groundwater at two naval sites.

    PubMed

    Wilson, Fernanda Paes; Cupples, Alison M

    2016-08-01

    The explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has long been recognized as a problematic environmental pollutant, and efforts to remediate contaminated soils, sediments, and groundwater have been going on for decades. In recent years, much interest has focused on using bioremediation to clean up these sites. The current study investigated the microorganisms (16S rRNA genes, Illumina) and functional genes (xenA, xenB, and xplA) linked to RDX biodegradation in microcosms composed of sediment or groundwater from two Navy sites. For this, experiments included sediment samples from three depths (5 to 30 ft) from two wells located in one Navy site. In addition, the groundwater upstream and downstream of an emulsified oil biobarrier was examined from another Navy site. Further, for the groundwater experiments, the effect of glucose addition was explored. For the sediment experiments, the most enriched phylotypes during RDX degradation varied over time, by depth and well locations. However, several trends were noted, including the enrichment of Pseudomonas, Rhodococcus, Arthrobacter, and Sporolactobacillus in the sediment microcosms. For the groundwater-based experiments, Pseudomonas, unclassified Rhodocyclaceae, Sphingomonas, and Rhodococcus were also highly abundant during RDX degradation. The abundance of both xplA and xenA significantly increased during RDX degradation compared to the control microcosms for many treatments (both groundwater and sediment microcosms). In a limited number of microcosms, the copy number of the xenB gene increased. Phylotype data were correlated with functional gene data to highlight potentially important biomarkers for RDX biodegradation at these two Navy sites. PMID:27118012

  5. Hexadecane and pristane degradation potential at the level of the aquifer--evidence from sediment incubations compared to in situ microcosms.

    PubMed

    Schurig, Christian; Miltner, Anja; Kaestner, Matthias

    2014-01-01

    Monitored natural attenuation is widely accepted as a sustainable remediation method. However, methods providing proof of proceeding natural attenuation within the water-unsaturated (vadose) zone are still relying on proxies such as measurements of reactive and non-reactive gases, or sediment sampling and subsequent mineralisation assays, under artificial conditions in the laboratory. In particular, at field sites contaminated with hydrophobic compounds, e.g. crude oil spills, an in situ evaluation of natural attenuation is needed, because in situ methods are assumed to provide less bias than investigations applying either proxies for biodegradation or off-site microcosm experiments. In order to compare the current toolbox of methods with the recently developed in situ microcosms, incubations with direct push-sampled sediments from the vadose and the aquifer zones of a site contaminated with crude oil were carried out in conventional microcosms and in situ microcosms. The results demonstrate the applicability of the in situ microcosm approach also outside water-saturated aquifer conditions in the vadose zone. The sediment incubation experiments demonstrated turnover rates in a similar range (vadose, 4.7 mg/kg*day; aquifer, 6.4 mghexadecane/kgsoil/day) of hexadecane degradation in the vadose zone and the aquifer, although mediated by slightly different microbial communities according to the analysis of fatty acid patterns and amounts. Additional experiments had the task of evaluating the degradation potential for the branched-chain alkane pristane (2,6,10,14-tetramethylpentadecane). Although this compound is regarded to be hardly degradable in comparison to n-alkanes and is thus frequently used as a reference parameter for indexing the extent of biodegradation of crude oils, it could be shown to be degraded by means of the incubation experiments. Thus, the site had a high inherent potential for natural attenuation of crude oils both in the vadose zone and the

  6. The relative impacts of spills of two alternative fuels on the microalgae of a sandy site: a microcosm study.

    PubMed

    Suderman, Keith; Thistle, David

    2004-09-01

    Electric power generation in the United States uses substantial amounts of fuel oil #6. Orimulsion, an emulsion of bitumen, water, and a surfactant, is an alternative. A portion of the information that managers need to compare the two fuels is their relative environmental impacts. Both fuels are shipped by sea, so the impact of spills on the marine benthos is a concern. We used microcosms to assess the relative impacts of simulated spills of these fuels on the microalgae of shallow subtidal sandy bottoms. Response variables included microalgal abundance, primary productivity, ratio of chlorophyll a to phaeophytin, and ratio of primary production to chlorophyll a. During our 88-day experiment, we found no significant differences between the fuels for any variable. We suggest that weathering before the spill reaches the shore removes the most toxic components, rendering the fuels essentially equal in their impact on benthic microalgae. PMID:15325215

  7. Aquifer microcosms and in situ methods to test the fate and function of pollutant-degrading microorganisms

    SciTech Connect

    Krumme, M.L.; Dwyer, D. . Inst. fuer Biotechnologie); Thiem, S.M.; Tiedje, J.M. ); Smith, R.L. )

    1990-01-01

    Little information is available on groundwater microorganism ecology, and specifically on the distribution and biochemical diversity of pollution degrading microorganisms in the aquifer. While the introduction of nutrients and electron acceptors may stimulate natural populations to degrade certain pollutants, low levels of pollutants and complex mixtures of pollutants may require the modification of natural populations through selective pressure or by means of genetic engineering. This study was designed to address these issues by examining three populations of substituted aromatic compound-degraders: an indigenous population, an introduced degrader, and a genetically engineered microorganism (GEM) in the environmental conditions of a sand and gravel aquifer. The goals of this study are to gain field experience on the fate and function of pollutant-degrading organisms in the aquifer and to evaluate column microcosms and survival chambers as tools for predicting the fate and function of selected and modified bacterial strains as appropriate aquifer bioremediation agents. 6 figs.

  8. Metagenomic data of the bacterial community in coastal Gulf of Mexico sediment microcosms following exposure to Macondo oil (MC252)

    PubMed Central

    Koo, Hyunmin; Bej, Asim K.

    2015-01-01

    The data in this article includes the sequences of bacterial 16S rRNA gene from metagenome of Macondo oil (MC252)-treated and non-oil-treated sediment microcosms, collected from coastal Gulf of Mexico and Bayou La Batre, USA. Metacommunity DNA was PCR amplified with 341F and 907R oligonucleotide primers, targeting V3–V5 regions of the 16S rRNA gene. Data were generated by using bacterial tag-encoded FLX-amplicon pyrosequencing (bTEFAP) methodology and then processed using bioinformatics tools such as QIIME. The data information is deposited to NCBI׳s BioProject and BioSample and raw sequence files are available via NCBI׳s Sequence Read Archive (SRA) database. PMID:26858973

  9. Distribution and composition of polycyclic aromatic hydrocarbons within experimental microcosms treated with creosote-impregnated Douglas fir pilings

    SciTech Connect

    Bestari, K.T.J.; Solomon, K.R.; Steele, T.S.; Sibley, P.K.; Robinson, R.D.; Day, K.E.

    1998-12-01

    Temporal changes in the concentration and relative composition of 15 priority polycyclic aromatic hydrocarbons (PAHs) in water, sediment, and polyvinylchloride (PVC) strips were assessed to evaluate the fate of creosote leached from impregnated wood pilings in aquatic environments. The study consisted of single microcosms containing one of 0.5, 1, 2, 3, 4, or 6 creosote-impregnated pilings and two microcosms containing untreated pilings. Quantitative analyses of PAHs were performed using high-performance liquid chromatography equipped with a fluorescence detector. For each treatment, total PAHs ({Sigma} PAH) in water increased rapidly up to 7 d posttreatment yielding a clear dose-dependant concentration gradient ranging from 7.3 to 97.2 {micro}g/L. Total PAHs declined exponentially after 7 d and was reduced close to background concentrations by the end of the study. No increase in {Sigma} PAH was observed in sediments at any treatment, nor was there any relationship between sediment PAHs and distance from each piling cluster. However, a slight increase in PAHs was observed on PVC liner strips that exhibited a concentration gradient similar to that in water. The PVC-bound {Sigma} PAH ranged from 0.3 to 2.4 {micro}g/cm{sup 2} and 0.2 to 2.2 {micro}g/cm{sup 2} at 31 and 58 d posttreatment, respectively. Based on these data, the authors estimated a rate loss of creosote from the pilings of approximately 50 {micro}g/cm{sup 2}/d. The low concentration of PAHs on the PVC, along with the absence of accumulation of PAHs in sediments, suggests that creosote was lost primarily from water via degradative pathways such as photolysis and microbial decomposition and adsorption onto PVC. The rapid loss of creosote from water in conjunction with the slow rate of leaching from the pilings suggests that risks associated with the use of creosote-impregnated pilings in aquatic environments may be minimal.

  10. Entry of Yersinia pestis into the Viable but Nonculturable State in a Low-Temperature Tap Water Microcosm

    PubMed Central

    Pawlowski, David R.; Metzger, Daniel J.; Raslawsky, Amy; Howlett, Amy; Siebert, Gretchen; Karalus, Richard J.; Garrett, Stephanie; Whitehouse, Chris A.

    2011-01-01

    Yersinia pestis, the causative agent of plague, has caused several pandemics throughout history and remains endemic in the rodent populations of the western United States. More recently, Y. pestis is one of several bacterial pathogens considered to be a potential agent of bioterrorism. Thus, elucidating potential mechanisms of survival and persistence in the environment would be important in the event of an intentional release of the organism. One such mechanism is entry into the viable but non-culturable (VBNC) state, as has been demonstrated for several other bacterial pathogens. In this study, we showed that Y. pestis became nonculturable by normal laboratory methods after 21 days in a low-temperature tap water microcosm. We further show evidence that, after the loss of culturability, the cells remained viable by using a variety of criteria, including cellular membrane integrity, uptake and incorporation of radiolabeled amino acids, and protection of genomic DNA from DNase I digestion. Additionally, we identified morphological and ultrastructural characteristics of Y. pestis VBNC cells, such as cell rounding and large periplasmic spaces, by electron microscopy, which are consistent with entry into the VBNC state in other bacteria. Finally, we demonstrated resuscitation of a small number of the non-culturable cells. This study provides compelling evidence that Y. pestis persists in a low-temperature tap water microcosm in a viable state yet is unable to be cultured under normal laboratory conditions, which may prove useful in risk assessment and remediation efforts, particularly in the event of an intentional release of this organism. PMID:21436885

  11. Degradation Network Reconstruction in Uric Acid and Ammonium Amendments in Oil-Degrading Marine Microcosms Guided by Metagenomic Data

    PubMed Central

    Bargiela, Rafael; Gertler, Christoph; Magagnini, Mirko; Mapelli, Francesca; Chen, Jianwei; Daffonchio, Daniele; Golyshin, Peter N.; Ferrer, Manuel

    2015-01-01

    Biostimulation with different nitrogen sources is often regarded as a strategy of choice in combating oil spills in marine environments. Such environments are typically depleted in nitrogen, therefore limiting the balanced microbial utilization of carbon-rich petroleum constituents. It is fundamental, yet only scarcely accounted for, to analyze the catabolic consequences of application of biostimulants. Here, we examined such alterations in enrichment microcosms using sediments from chronically crude oil-contaminated marine sediment at Ancona harbor (Italy) amended with natural fertilizer, uric acid (UA), or ammonium (AMM). We applied the web-based AromaDeg resource using as query Illumina HiSeq meta-sequences (UA: 27,893 open reading frames; AMM: 32,180) to identify potential catabolic differences. A total of 45 (for UA) and 65 (AMM) gene sequences encoding key catabolic enzymes matched AromaDeg, and their participation in aromatic degradation reactions could be unambiguously suggested. Genomic signatures for the degradation of aromatics such as 2-chlorobenzoate, indole-3-acetate, biphenyl, gentisate, quinoline and phenanthrene were common for both microcosms. However, those for the degradation of orcinol, ibuprofen, phenylpropionate, homoprotocatechuate and benzene (in UA) and 4-aminobenzene-sulfonate, p-cumate, dibenzofuran and phthalate (in AMM), were selectively enriched. Experimental validation was conducted and good agreement with predictions was observed. This suggests certain discrepancies in action of these biostimulants on the genomic content of the initial microbial community for the catabolism of petroleum constituents or aromatics pollutants. In both cases, the emerging microbial communities were phylogenetically highly similar and were composed by very same proteobacterial families. However, examination of taxonomic assignments further revealed different catabolic pathway organization at the organismal level, which should be considered for designing

  12. The pH response to urea and the effect of liquid flow in 'artificial mouth' microcosm plaques.

    PubMed

    Sissons, C H; Wong, L; Hancock, E M; Cutress, T W

    1994-06-01

    This study examined in detailed the pH response of microcosm plaque biofilms to the application of 500 mmol/l urea, and the effect of modifying the flow rate of BMM (a basal medium containing 0.25% mucin). Microcosm plaques were cultured from the mixed salivary bacteria in a multi-plaque 'artificial mouth' supplied continuously with BMM at 3.6 ml/h per plaque, and periodically with sucrose (5 or 10%). Urea (500 mmol/l) induced a pH response that was the inverse of the Stephan pH curve induced by sucrose. In thicker plaques the ureolytic pH response was delayed and slower. With no BMM flow, the urea-induced pH curve reached a maximum and then slowly decreased indicating loss of ammonia. A flow of BMM reduced the magnitude of the pH response. Urea dilution explained (r2 = 0.97) the reduction in the maximum rate of pH rise caused by an increasing BMM flow. There were, however, additional flow-rate effects on the magnitude of the pH rise, the curve areas and the maximum rate of pH decrease back to the resting pH. These effects were greatest at low BMM flow rates, indicating that ammonia clearance may be limited at higher flow rates by the rate of intraplaque diffusion and metabolism. Application of 50 instead of 500 mmol/l urea reduced the rate of pH rise about 10-fold, and the area of the curve about seven fold. Metabolism of arginine (50 mmol/l) generated only about half the pH response of the same amount of urea.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8067919

  13. The use of in situ and stream microcosm experiments to assess population- and community-level responses to metals.

    PubMed

    Clark, Jeffrey L; Clements, William H

    2006-09-01

    We conducted field and stream microcosm experiments to assess population-level (density, size distribution) and community-level (species richness metrics, multivariate analysis of community composition) responses of macroinvertebrates to heavy metals in the Arkansas River, a mining-polluted stream in Colorado, USA. Experiments were conducted in spring and summer to coincide with early and late developmental stages (i.e., instars) of the mayfly Rhithrogena hageni. Results of field experiments showed significant mortality at metal-contaminated sites during summer when mayfly populations were dominated by small, early instars (mean dry wt = 0.13 mg). In contrast, no significant mortality was observed in spring when organisms were larger (mean dry wt = 1.78 mg). Multivariate analyses based on abundance of dominant taxa clearly separated reference and metal-impacted stations in summer experiments but showed little separation in spring. We observed no significant effects of metals on species richness, number of mayfly species, or EPT (species richness of Ephemeroptera, Plecoptera, and Trichoptera) in.either field experiment. Using stream microcosms, we established concentration-response relationships between heavy metals and R. hageni density, species richness, mayfly richness, and EPT. Density of R. hageni was generally more sensitive to metals than measures of species richness, and summer populations of R. hageni were more sensitive to metals than spring populations. Because the presence of large, relatively tolerant individuals in spring coincided with periods of higher metal concentrations, R. hageni was protected from toxic effects in this system. We conclude that phenology and developmental stage are important factors influencing responses of some aquatic macroinvertebrates to metals. Thus, timing bioassessments to coincide with the presence of these sensitive life stages can improve our ability to detect subtle contaminant effects. PMID:16986784

  14. Degradation Network Reconstruction in Uric Acid and Ammonium Amendments in Oil-Degrading Marine Microcosms Guided by Metagenomic Data.

    PubMed

    Bargiela, Rafael; Gertler, Christoph; Magagnini, Mirko; Mapelli, Francesca; Chen, Jianwei; Daffonchio, Daniele; Golyshin, Peter N; Ferrer, Manuel

    2015-01-01

    Biostimulation with different nitrogen sources is often regarded as a strategy of choice in combating oil spills in marine environments. Such environments are typically depleted in nitrogen, therefore limiting the balanced microbial utilization of carbon-rich petroleum constituents. It is fundamental, yet only scarcely accounted for, to analyze the catabolic consequences of application of biostimulants. Here, we examined such alterations in enrichment microcosms using sediments from chronically crude oil-contaminated marine sediment at Ancona harbor (Italy) amended with natural fertilizer, uric acid (UA), or ammonium (AMM). We applied the web-based AromaDeg resource using as query Illumina HiSeq meta-sequences (UA: 27,893 open reading frames; AMM: 32,180) to identify potential catabolic differences. A total of 45 (for UA) and 65 (AMM) gene sequences encoding key catabolic enzymes matched AromaDeg, and their participation in aromatic degradation reactions could be unambiguously suggested. Genomic signatures for the degradation of aromatics such as 2-chlorobenzoate, indole-3-acetate, biphenyl, gentisate, quinoline and phenanthrene were common for both microcosms. However, those for the degradation of orcinol, ibuprofen, phenylpropionate, homoprotocatechuate and benzene (in UA) and 4-aminobenzene-sulfonate, p-cumate, dibenzofuran and phthalate (in AMM), were selectively enriched. Experimental validation was conducted and good agreement with predictions was observed. This suggests certain discrepancies in action of these biostimulants on the genomic content of the initial microbial community for the catabolism of petroleum constituents or aromatics pollutants. In both cases, the emerging microbial communities were phylogenetically highly similar and were composed by very same proteobacterial families. However, examination of taxonomic assignments further revealed different catabolic pathway organization at the organismal level, which should be considered for designing

  15. The intact capture of hypervelocity dust particles using underdense foams

    NASA Technical Reports Server (NTRS)

    Maag, Carl R.; Borg, J.; Tanner, William G.; Stevenson, T. J.; Bibring, J.-P.

    1994-01-01

    probability of survival for the impacting particle. The primary objectives of the experiment are to (1) Examine the morphology of primary and secondary hypervelocity impact craters. Primary attention will be paid to craters caused by ejecta during hypervelocity impacts of different substrates. (2) Determine the size distribution of ejecta by means of witness plates and collect fragments of ejecta from craters by means of momentum-sensitive mcropore foam. (3) Assess the directionality of the flux by means of penetration-hole alignment of thin films placed above the cells. (4) Capture intact the particles that perforated the thin film and entered the cell. Capture media consisted of both previously flight-tested micropore foams and aerogel. The foams had different latent heats of fusion and, accordingly, will capture particles over a range of momenta. Aerogel was incorporated into the cells to determine the minimum diameter than can be captured intact.

  16. Multipurpose Dissociation Cell for Enhanced ETD of Intact Protein Species

    NASA Astrophysics Data System (ADS)

    Rose, Christopher M.; Russell, Jason D.; Ledvina, Aaron R.; McAlister, Graeme C.; Westphall, Michael S.; Griep-Raming, Jens; Schwartz, Jae C.; Coon, Joshua J.; Syka, John E. P.

    2013-06-01

    We describe and characterize an improved implementation of ETD on a modified hybrid linear ion trap-Orbitrap instrument. Instead of performing ETD in the mass-analyzing quadrupole linear ion trap (A-QLT), the instrument collision cell was modified to enable ETD. We partitioned the collision cell into a multi-section rf ion storage and transfer device to enable injection and simultaneous separate storage of precursor and reagent ions. Application of a secondary (axial) confinement voltage to the cell end lens electrodes enables charge-sign independent trapping for ion-ion reactions. The approximately 2-fold higher quadrupole field frequency of this cell relative to that of the A-QLT enables higher reagent ion densities and correspondingly faster ETD reactions, and, with the collision cell's longer axial dimensions, larger populations of precursor ions may be reacted. The higher ion capacity of the collision cell permits the accumulation and reaction of multiple full loads of precursor ions from the A-QLT followed by FT Orbitrap m/z analysis of the ETD product ions. This extends the intra-scan dynamic range by increasing the maximum number of product ions in a single MS/MS event. For analyses of large peptide/small protein precursor cations, this reduces or eliminates the need for spectral averaging to achieve acceptable ETD product ion signal-to-noise levels. Using larger ion populations, we demonstrate improvements in protein sequence coverage and aggregate protein identifications in LC-MS/MS analysis of intact protein species as compared to the standard ETD implementation.

  17. The effects of silver nanoparticles on intact wastewater biofilms

    PubMed Central

    Sheng, Zhiya; Van Nostrand, Joy D.; Zhou, Jizhong; Liu, Yang

    2015-01-01

    Silver nanoparticles (Ag-NPs) have strong antibacterial properties, which may adversely affect biological wastewater treatment processes. To determine the overall effect, intact biofilm samples were collected from the rotating biological contactor at the local wastewater treatment plant and treated with 200 mg Ag/L Ag-NPs for 24 h. The biofilm uptake of Ag-NPs was monitored with transmission electron microscopy. Forty-five minutes after Ag-NP application, Ag-NPs were seen in the biofilm extracellular polymeric substances (EPS). After 24 h, Ag-NPs had entered certain microbial cells, while other cells contained no observable Ag-NPs. Some cells were dying after the uptake of Ag-NPs. However, there was no significant reduction in cultivable bacteria in the biofilms, based on heterotrophic plate counts (HPC). While this may indicate that wastewater biofilms are highly resistant to Ag-NPs, the HPC represents only a small portion of the total microbial population. To further investigate the effects of Ag-NPs, a GeoChip microarray was used to directly detect changes in the functional gene structure of the microbial community in the biofilm. A clear decrease (34.6% decreases in gene number) in gene diversity was evident in the GeoChip analysis. However, the complete loss of any specific gene was rare. Most gene families present in both treated and untreated biofilms. However, this doesn’t necessarily mean that there was no change in these families. Signal intensity decreased in certain variants in each family while other variants increased to compensate the effects of Ag-NPs. The results indicate that Ag-NP treatment decreased microbial community diversity but did not significantly affect the microbial community function. This provides direct evidence for the functional redundancy of microbial community in engineered ecosystems such as wastewater biofilms. PMID:26217316

  18. Mechanisms of neuronal chloride accumulation in intact mouse olfactory epithelium

    PubMed Central

    Nickell, William T; Kleene, Nancy K; Kleene, Steven J

    2007-01-01

    When olfactory receptor neurons respond to odours, a depolarizing Cl− efflux is a substantial part of the response. This requires that the resting neuron accumulate Cl− against an electrochemical gradient. In isolated olfactory receptor neurons, the Na+–K+–2Cl− cotransporter NKCC1 is essential for Cl− accumulation. However, in intact epithelium, a robust electrical olfactory response persists in mice lacking NKCC1. This response is largely due to a neuronal Cl− efflux. It thus appears that NKCC1 is an important part of a more complex system of Cl− accumulation. To identify the remaining transport proteins, we first screened by RT-PCR for 21 Cl− transporters in mouse nasal tissue containing olfactory mucosa. For most of the Cl− transporters, the presence of mRNA was demonstrated. We also investigated the effects of pharmacological block or genetic ablation of Cl− transporters on the olfactory field potential, the electroolfactogram (EOG). Mice lacking the common Cl−/HCO3− exchanger AE2 had normal EOGs. Block of NKCC cotransport with bumetanide reduced the EOG in epithelia from wild-type mice but had no effect in mice lacking NKCC1. Hydrochlorothiazide, a blocker of the Na+–Cl− cotransporter, had only a small effect. DIDS, a blocker of some KCC cotransporters and Cl−/HCO3− exchangers, reduced the EOG in epithelia from both wild-type and NKCC1 knockout mice. A combination of bumetanide and DIDS decreased the response more than either drug alone. However, no combination of drugs completely abolished the Cl− component of the response. These results support the involvement of both NKCC1 and one or more DIDS-sensitive transporters in Cl− accumulation in olfactory receptor neurons. PMID:17656441

  19. Mechanisms of neuronal chloride accumulation in intact mouse olfactory epithelium.

    PubMed

    Nickell, William T; Kleene, Nancy K; Kleene, Steven J

    2007-09-15

    When olfactory receptor neurons respond to odours, a depolarizing Cl(-) efflux is a substantial part of the response. This requires that the resting neuron accumulate Cl(-) against an electrochemical gradient. In isolated olfactory receptor neurons, the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 is essential for Cl(-) accumulation. However, in intact epithelium, a robust electrical olfactory response persists in mice lacking NKCC1. This response is largely due to a neuronal Cl(-) efflux. It thus appears that NKCC1 is an important part of a more complex system of Cl(-) accumulation. To identify the remaining transport proteins, we first screened by RT-PCR for 21 Cl(-) transporters in mouse nasal tissue containing olfactory mucosa. For most of the Cl(-) transporters, the presence of mRNA was demonstrated. We also investigated the effects of pharmacological block or genetic ablation of Cl(-) transporters on the olfactory field potential, the electroolfactogram (EOG). Mice lacking the common Cl(-)/HCO(3)(-) exchanger AE2 had normal EOGs. Block of NKCC cotransport with bumetanide reduced the EOG in epithelia from wild-type mice but had no effect in mice lacking NKCC1. Hydrochlorothiazide, a blocker of the Na(+)-Cl(-) cotransporter, had only a small effect. DIDS, a blocker of some KCC cotransporters and Cl(-)/HCO(3)(-) exchangers, reduced the EOG in epithelia from both wild-type and NKCC1 knockout mice. A combination of bumetanide and DIDS decreased the response more than either drug alone. However, no combination of drugs completely abolished the Cl(-) component of the response. These results support the involvement of both NKCC1 and one or more DIDS-sensitive transporters in Cl(-) accumulation in olfactory receptor neurons. PMID:17656441

  20. Spatial variations in membrane properties in the intact rat lens.

    PubMed Central

    Baldo, G J; Mathias, R T

    1992-01-01

    We have used linear frequency domain techniques to measure impedance at various locations and depths in the intact rat lens. The data are used to obtain best-fit solutions to a new electrical model based on lens structure, allowing us to estimate localized conductances of surface cell membranes (Gs), fiber cell membranes (gm), and gap junctions (Gj) as functions of position. We find that gm is small and fairly uniform throughout the lens (2.02 +/- 0.58 microS/cm2); for the anterior surface-epithelial cells Gs = 1.26 +/- 0.19 mS/cm2; for the posterior surface differentiating fiber cells Gs = 0.46 +/- 0.04 mS/cm2. Thus, Gs varies about the equator in a stepwise fashion. Gj between fiber cells at locations interior to 80% of the radius is fairly uniform (0.75 S/cm2); but in the outer 20% Gj varies smoothly and symmetrically from both poles (0.66 S/cm2) to equator (5.95 S/cm2). This pattern of variation in Gj is similar to the pattern of inward and outward currents reported by Robinson and Patterson (1983. Curr. Eye Res. 2:843-847). We therefore suggest that the nonuniform distribution of functional gap junctions, not the surface cell conductance or Na/K pumps, may be responsible for directing these current flows. Gap junctional uncoupling during exposure to elevated calcium and acidification was also examined. High calcium (20 mM, with the calcium ionophore A23187) produced modest (twofold) irreversible uncoupling along with large, irreversible decreases in membrane potential. We did not pursue this further. Acidification with 20 and 100% CO2-bubbled Tyrode's produced 5- and 15-fold reversible uncoupling, respectively, only in the outer 20% of the lens radius. The remaining inner 80% of the lens gap junctions seemed resistant to the acidification and did not uncouple. PMID:1420894

  1. Optical properties of intact leaves for estimating chlorophyll concentration

    NASA Technical Reports Server (NTRS)

    Carter, Gregory A.; Spiering, Bruce A.

    2002-01-01

    Changes in leaf chlorophyll content can serve as relative indicators of plant vigor and environmental quality. This study identified reflectance, transmittance, and absorptance wavebands and band ratios within the 400- to 850-nm range for intact leaves that could be used to estimate extracted leaf chlorophyll per unit leaf area (areal concentration) with minimal error. Leaf optical properties along with chlorophyll a, b, and a + b concentrations were measured for the planar-leaved sweetgum (Liquidambar styraciflua L.), red maple (Acer rubrum L.), wild grape (Vitis rotundifolia Michx.), and switchcane [Arundinaria gigantea (Walter) Muhl.], and for needles of longleaf pine (Pinus palustris Miller). Generally, reflectance, transmittance, and absorptance corresponded most precisely with chlorophyll concentrations at wavelengths near 700 nm, although regressions were also strong in the 550- to 625-nm range. A power function was superior to a simple linear function in yielding low standard deviations of the estimate (s). When data were combined among the planar-leaved species, s values were low at approximately 50 mumol/m2 out of a 940 mumol/m2 range in chlorophyll a + b at best-fit wavelengths of 707 to 709 nm. Minimal s values for chlorophyll a + b ranged from 32 to 62 mumol/m2 across species when band ratios having numerator wavelengths of 693 to 720 nm were used with the application of a power function. Optimal denominator wavelengths for the band ratios were 850 nm for reflectance and transmittance and 400 nm for absorptance. This information can be applied in designing field portable chlorophyll meters and in the landscape-scale remote sensing of plant responses to the environment.

  2. Partial characterization of cyclic electron transport in intact chloroplasts

    SciTech Connect

    Crowther, D.; Hind, G.

    1980-10-15

    Turnover of the cyclic electron transfer chain around photosystem I in intact chloroplasts was induced by addition of sodium dithionite after poisoning with 3-(3,4-dichlorophenyl)-1,1-dimethylurea. A substantial permeability barrier to dithionite allowed redox poising to a level sufficiently negative to active, but not overreduce, the cycle. Spectral changes could thus be studied without interference from photosystem II reactions. Illumination by repetitive single-turnover flashes showed the participation in the cycle of cytochromes f and b/sub 563/ with an apparent 1:1 stoichiometry. The rise of the flash-induced electrochromic bandshift showed a fast phase with rise time < 10 ..mu..s and a slow phase with rise time variable in the millisecond range. The slow phase had an amplitude equal to that of the fast phase and occurred only when electron transfer between cytochromes b/sub 563/ and f was uninhibited. A kinetic correlation was observed between the rise of the slow phase and the rereduction of cytochrome f, whereas cytochrome b/sub 563/ reoxidation was slower than both. Redox titrations of the appearance of the slow rise in the P518 response showed that it was only observed on repetitive flashes when a component of midpoint potential approx. = -55mV(pH 8.1), n = 2, was reduced before the flash. A comparison is drawn between this protonmotive electron transfer cycle and that of the purple nonsulfur bacterium Rhodopseudomonas capsulata; possible arrangements of electron carriers in the photosystem I cycle are discussed, and a modified Q cycle is proposed to account for the properties observed.

  3. The effects of silver nanoparticles on intact wastewater biofilms.

    PubMed

    Sheng, Zhiya; Van Nostrand, Joy D; Zhou, Jizhong; Liu, Yang

    2015-01-01

    Silver nanoparticles (Ag-NPs) have strong antibacterial properties, which may adversely affect biological wastewater treatment processes. To determine the overall effect, intact biofilm samples were collected from the rotating biological contactor at the local wastewater treatment plant and treated with 200 mg Ag/L Ag-NPs for 24 h. The biofilm uptake of Ag-NPs was monitored with transmission electron microscopy. Forty-five minutes after Ag-NP application, Ag-NPs were seen in the biofilm extracellular polymeric substances (EPS). After 24 h, Ag-NPs had entered certain microbial cells, while other cells contained no observable Ag-NPs. Some cells were dying after the uptake of Ag-NPs. However, there was no significant reduction in cultivable bacteria in the biofilms, based on heterotrophic plate counts (HPC). While this may indicate that wastewater biofilms are highly resistant to Ag-NPs, the HPC represents only a small portion of the total microbial population. To further investigate the effects of Ag-NPs, a GeoChip microarray was used to directly detect changes in the functional gene structure of the microbial community in the biofilm. A clear decrease (34.6% decreases in gene number) in gene diversity was evident in the GeoChip analysis. However, the complete loss of any specific gene was rare. Most gene families present in both treated and untreated biofilms. However, this doesn't necessarily mean that there was no change in these families. Signal intensity decreased in certain variants in each family while other variants increased to compensate the effects of Ag-NPs. The results indicate that Ag-NP treatment decreased microbial community diversity but did not significantly affect the microbial community function. This provides direct evidence for the functional redundancy of microbial community in engineered ecosystems such as wastewater biofilms. PMID:26217316

  4. Multipurpose Dissociation Cell for Enhanced ETD of Intact Protein Species

    PubMed Central

    Rose, Christopher M.; Russell, Jason D.; Ledvina, Aaron R.; McAlister, Graeme C.; Westphall, Michael S.; Griep-Raming, Jens; Schwartz, Jae C.; Coon, Joshua J.; Syka, John E.P.

    2013-01-01

    We describe and characterize an improved implementation of ETD on a modified hybrid linear ion trap-Orbitrap instrument. Instead of performing ETD in the mass-analyzing quadrupole linear ion trap (A-QLT), the instrument collision cell was modified to enable ETD. We partitioned the collision cell into a multi-section RF ion storage and transfer device to enable injection and simultaneous separate storage of precursor and reagent ions. Application of a secondary (axial) confinement voltage to the cell end lens electrodes enables charge-sign independent trapping for ion-ion reactions. The approximately two-fold higher quadrupole field frequency of this cell relative to that of the A-QLT, enables higher reagent ion densities and correspondingly faster ETD reactions, and, with the collision cell’s longer axial dimensions, larger populations of precursor ions may be reacted. The higher ion capacity of the collision cell permits the accumulation and reaction of multiple full loads of precursor ions from the A-QLT followed by FT Orbitrap m/z analysis of the ETD product ions. This extends the intra-scan dynamic range by increasing the maximum number of product ions in a single MS/MS event. For analyses of large peptide/small protein precursor cations, this reduces or eliminates the need for spectral averaging to achieve acceptable ETD product ion signal-to-noise levels. Using larger ion populations, we demonstrate improvements in protein sequence coverage and aggregate protein identifications in LC-MS/MS analysis of intact protein species as compared to the standard ETD implementation. PMID:23609185

  5. Voltage clamping single cells in intact malpighian tubules of mosquitoes.

    PubMed

    Masia, R; Aneshansley, D; Nagel, W; Nachman, R J; Beyenbach, K W

    2000-10-01

    Principal cells of the Malpighian tubule of the yellow fever mosquito were studied with the methods of two-electrode voltage clamp (TEVC). Intracellular voltage (V(pc)) was -86.7 mV, and input resistance (R(pc)) was 388.5 kOmega (n = 49 cells). In six cells, Ba(2+) (15 mM) had negligible effects on V(pc), but it increased R(pc) from 325.3 to 684.5 kOmega (P < 0.001). In the presence of Ba(2+), leucokinin-VIII (1 microM) increased V(pc) to -101.8 mV (P < 0.001) and reduced R(pc) to 340.2 kOmega (P < 0.002). Circuit analysis yields the following: basolateral membrane resistance, 652. 0 kOmega; apical membrane resistance, 340.2 kOmega; shunt resistance (R(sh)), 344.3 kOmega; transcellular resistance, 992.2 kOmega. The fractional resistance of the apical membrane (0.35) and the ratio of transcellular resistance and R(sh) (3.53) agree closely with values obtained by cable analysis in isolated perfused tubules and confirm the usefulness of TEVC methods in single principal cells of the intact Malpighian tubule. Dinitrophenol (0.1 mM) reversibly depolarized V(pc) from -94.3 to -10.7 mV (P < 0.001) and reversibly increased R(pc) from 412 to 2,879 kOmega (P < 0.001), effects that were duplicated by cyanide (0.3 mM). Significant effects of metabolic inhibition on voltage and resistance suggest a role of ATP in electrogenesis and the maintenance of conductive transport pathways. PMID:10997925

  6. Raman mapping of intact biofilms on stainless steel surfaces

    NASA Astrophysics Data System (ADS)

    Nguyen, Julie K.; Heighton, Lynne; Xu, Yunfeng; Nou, Xiangwu; Schmidt, Walter F.

    2016-05-01

    Many issues occur when microbial bacteria contaminates human food or water; it can be dangerous to the public. Determining how the microbial are growing, it can help experts determine how to prevent the outbreaks. Biofilms are a tightly group of microbial cells that grow on living surfaces or surrounding themselves. Though biofilms are not necessarily uniform; when there are more than one type of microbial bacteria that are grown, Raman mapping is performed to determine the growth patterns. Depending on the type of microbial bacteria, they can grow in various patterns such as symmetrical or scattered on the surface. The biofilms need to be intact in order to preclude and potentially figuring out the relative intensity of different components in a biofilm mixture. In addition, it is important to determine whether one biofilms is a substrate for another biofilm to be detected. For example, it is possible if layer B appears above layer A, but layer A doesn't appear above layer B. In this case, three types of biofilms that are grown includes Listeria(L), Ralstonia(R), and a mixture of the two (LR). Since microbe deposits on metal surfaces are quite suitable, biofilms were grown on stainless steel surface slides. Each slide was viewed under a Raman Microscope at 100X and using a 532nm laser to provide great results and sharp peaks. The mapping of the laser helps determine how the bacteria growth, at which intensity the bacteria appeared in order to identify specific microbes to signature markers on biofilms.

  7. Physical adsorption analysis of intact supported MFI zeolite membranes.

    PubMed

    Hammond, Karl D; Tompsett, Geoffrey A; Auerbach, Scott M; Conner, W Curtis

    2007-07-31

    We compare the adsorption properties of intact supported silicalite membranes with those of silicalite powder and of alumina supports using nitrogen and argon as adsorbates at 77 K. We disentangle contributions from the membrane and support and find that the support contributes significantly to the total quantity adsorbed due to its relative thickness. The micropore-filling regions of the adsorption isotherms of the powder and the supported membrane are nearly identical for the membranes studied, but the isotherms differ at higher pressures--the supported membranes exhibit a much higher quantity adsorbed than the powders. Despite this difference, no hysteresis is observed in the membrane isotherms, indicating a lack of mesoporosity (pores in the 2-50 nm range) in either membrane or support for this preparation. We estimate argon transport fluxes at steady state by assuming surface diffusion with both a constant and concentration-dependent Maxwell-Stefan diffusion coefficient in the zeolite and the support. Further, we use the respective adsorption isotherms to determine the thermodynamic correction factors--that is, the ratios of the Fick and Maxwell-Stefan diffusion coefficients--required to solve the diffusion equation. The estimated argon flux is virtually the same using adsorption data from powders and membranes. For the relatively thick supports used in our study (approximately 2 mm), we find that the support exerts a much greater influence on the predicted fluxes for a wide range of values of the ratio of the support to zeolite diffusion coefficients. We emphasize that the results are specific to the architecture of the supported membranes studied, and thus, the results should be interpreted accordingly. PMID:17602679

  8. Assessing Fatigability in Mobility-Intact Older Adults

    PubMed Central

    Simonsick, Eleanor M.; Schrack, Jennifer A.; Glynn, Nancy W.; Ferrucci, Luigi

    2014-01-01

    OBJECTIVES Evaluate criterion validity of two measures of fatigability defined as performance deterioration or perceived effort to perform a standardized task. DESIGN Cross-sectional analysis of data from the Baltimore Longitudinal Study of Aging (BLSA). SETTING National Institute on Aging, Intramural Research Program, Clinical Research Unit, Baltimore, Maryland. PARTICIPANTS Six hundred five men (53.7%) and women (aged 65–97) participating in the BLSA eligible for endurance walk testing without a walking aid. MEASUREMENTS Fatigability was assessed using (1) completion status and lap times from a 400m-walk performed “as quickly as possible” and (2) perceived exertion rating using the Borg scale (range 6–20) following 5 minutes of treadmill walking at 1.5mph (0.67m/s). Criterion measures include self-report of tiredness, level of weakness and energy in past month and walking ability and objective measures of usual and fast gait speed, time to complete 10 chair stands and grip strength. Co-variates include age, race, sex, obesity, smoking status and walking activity. RESULTS Among mobility intact older persons, 23% exhibited performance deterioration (i.e., slowed or stopped) during the 400m-walk and1/3 reported more than very light exertion following a 5-minute slow walk. Slowing was strongly associated with self-reported fatigue and walking ability, but weakly associated with performance-based mobility measures. High perceived exertion was associated with tiredness and weakness and reported and observed mobility deficits. CONCLUSION Slowing down may have low sensitivity for identifying fatigability in older persons, but ascertaining perceived exertion during a defined workload shows promise. In seemingly healthy, motivated individuals, fatigue and fatigability were common and may impact socially meaningful mobility behaviors. Assessment of fatigability in well-elderly examinations may help identify threats to independent functioning earlier in the decline

  9. Intact reading in patients with profound early visual dysfunction

    PubMed Central

    Yong, Keir X.X.; Warren, Jason D.; Warrington, Elizabeth K.; Crutch, Sebastian J.

    2013-01-01

    Despite substantial neuroscientific evidence for a region of visual cortex dedicated to the processing of written words, many studies continue to reject explanations of letter-by-letter (LBL) reading in terms of impaired word form representations or parallel letter processing in favour of more general deficits of visual function. In the current paper, we demonstrate that whilst LBL reading is often associated with general visual deficits, these deficits are not necessarily sufficient to cause reading impairment and have led to accounts of LBL reading which are based largely on evidence of association rather than causation. We describe two patients with posterior cortical atrophy (PCA) who exhibit remarkably preserved whole word and letter reading despite profound visual dysfunction. Relative to controls, both patients demonstrated impaired performance on tests of early visual, visuoperceptual and visuospatial processing; visual acuity was the only skill preserved in both individuals. By contrast, both patients were able to read aloud words with perfect to near-perfect accuracy. Reading performance was also rapid with no overall significant difference in response latencies relative to age- and education-matched controls. Furthermore, the patients violated a key prediction of general visual accounts of LBL reading – that pre-lexical impairments should result in prominent word length effects; in the two reported patients, evidence for abnormal word length effects was equivocal or absent, and certainly an order of magnitude different to that reported for LBL readers. We argue that general visual accounts cannot explain the pattern of reading data reported, and attribute the preserved reading performance to preserved direct access to intact word form representations and/or parallel letter processing mechanisms. The current data emphasise the need for much clearer evidence of causality when attempting to draw connections between specific aspects of visual processing

  10. Pointing in visual periphery: is DF's dorsal stream intact?

    PubMed

    Hesse, Constanze; Ball, Keira; Schenk, Thomas

    2014-01-01

    Observations of the visual form agnosic patient DF have been highly influential in establishing the hypothesis that separate processing streams deal with vision for perception (ventral stream) and vision for action (dorsal stream). In this context, DF's preserved ability to perform visually-guided actions has been contrasted with the selective impairment of visuomotor performance in optic ataxia patients suffering from damage to dorsal stream areas. However, the recent finding that DF shows a thinning of the grey matter in the dorsal stream regions of both hemispheres in combination with the observation that her right-handed movements are impaired when they are performed in visual periphery has opened up the possibility that patient DF may potentially also be suffering from optic ataxia. If lesions to the posterior parietal cortex (dorsal stream) are bilateral, pointing and reaching deficits should be observed in both visual hemifields and for both hands when targets are viewed in visual periphery. Here, we tested DF's visuomotor performance when pointing with her left and her right hand toward targets presented in the left and the right visual field at three different visual eccentricities. Our results indicate that DF shows large and consistent impairments in all conditions. These findings imply that DF's dorsal stream atrophies are functionally relevant and hence challenge the idea that patient DF's seemingly normal visuomotor behaviour can be attributed to her intact dorsal stream. Instead, DF seems to be a patient who suffers from combined ventral and dorsal stream damage meaning that a new account is needed to explain why she shows such remarkably normal visuomotor behaviour in a number of tasks and conditions. PMID:24626162

  11. Multipurpose dissociation cell for enhanced ETD of intact protein species.

    PubMed

    Rose, Christopher M; Russell, Jason D; Ledvina, Aaron R; McAlister, Graeme C; Westphall, Michael S; Griep-Raming, Jens; Schwartz, Jae C; Coon, Joshua J; Syka, John E P

    2013-06-01

    We describe and characterize an improved implementation of ETD on a modified hybrid linear ion trap-Orbitrap instrument. Instead of performing ETD in the mass-analyzing quadrupole linear ion trap (A-QLT), the instrument collision cell was modified to enable ETD. We partitioned the collision cell into a multi-section rf ion storage and transfer device to enable injection and simultaneous separate storage of precursor and reagent ions. Application of a secondary (axial) confinement voltage to the cell end lens electrodes enables charge-sign independent trapping for ion-ion reactions. The approximately 2-fold higher quadrupole field frequency of this cell relative to that of the A-QLT enables higher reagent ion densities and correspondingly faster ETD reactions, and, with the collision cell's longer axial dimensions, larger populations of precursor ions may be reacted. The higher ion capacity of the collision cell permits the accumulation and reaction of multiple full loads of precursor ions from the A-QLT followed by FT Orbitrap m/z analysis of the ETD product ions. This extends the intra-scan dynamic range by increasing the maximum number of product ions in a single MS/MS event. For analyses of large peptide/small protein precursor cations, this reduces or eliminates the need for spectral averaging to achieve acceptable ETD product ion signal-to-noise levels. Using larger ion populations, we demonstrate improvements in protein sequence coverage and aggregate protein identifications in LC-MS/MS analysis of intact protein species as compared to the standard ETD implementation. PMID:23609185

  12. 46 CFR 28.545 - Intact stability when using lifting gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Intact stability when using lifting gear. 28.545 Section... COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.545 Intact stability when using lifting gear. (a) Each vessel which lifts a weight over the side, or that uses fishing gear that can impose an...

  13. 46 CFR 28.545 - Intact stability when using lifting gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Intact stability when using lifting gear. 28.545 Section... COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.545 Intact stability when using lifting gear. (a) Each vessel which lifts a weight over the side, or that uses fishing gear that can impose an...

  14. 46 CFR 28.545 - Intact stability when using lifting gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Intact stability when using lifting gear. 28.545 Section... COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.545 Intact stability when using lifting gear. (a) Each vessel which lifts a weight over the side, or that uses fishing gear that can impose an...

  15. 46 CFR 28.545 - Intact stability when using lifting gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Intact stability when using lifting gear. 28.545 Section... COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.545 Intact stability when using lifting gear. (a) Each vessel which lifts a weight over the side, or that uses fishing gear that can impose an...

  16. 46 CFR 28.545 - Intact stability when using lifting gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Intact stability when using lifting gear. 28.545 Section... COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.545 Intact stability when using lifting gear. (a) Each vessel which lifts a weight over the side, or that uses fishing gear that can impose an...

  17. Relationship between Size of Broken and Intact Families and Academic Achievement.

    ERIC Educational Resources Information Center

    Cherian, Varghese I.

    1991-01-01

    Compares relationship between family size and academic achievement of children from broken and intact families among Black African Xhosa-speaking children between the ages of 13 and 17. Results indicate a negative relationship between family size and academic achievement, regardless of broken or intact families. (Author/NL)

  18. 46 CFR 171.057 - Intact stability requirements for a sailing catamaran.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Intact stability requirements for a sailing catamaran... Intact stability requirements for a sailing catamaran. (a) A sailing vessel that operates on protected...) A sailing vessel that operates on partially protected or exposed waters must be designed to...

  19. 46 CFR 178.320 - Intact stability requirements-non-sailing vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Intact stability requirements-non-sailing vessels. 178.320 Section 178.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER... Intact stability requirements—non-sailing vessels. (a) As permitted by § 178.310(c) of this part,...

  20. 46 CFR 178.325 - Intact stability requirements for a sailing vessel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Intact stability requirements for a sailing vessel. 178... Intact stability requirements for a sailing vessel. (a) Except as provided in paragraphs (b), (c) and (e) of this section, each sailing vessel must undergo a simplified stability proof test in...