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Sample records for enhance bead-based bioassays

  1. All-plastic miniature fluorescence microscope for point-of-care readout of bead-based bioassays

    NASA Astrophysics Data System (ADS)

    Forcucci, Alessandra; Pawlowski, Michal Emanuel; Crannell, Zachary; Pavlova, Ina; Richards-Kortum, Rebecca; Tkaczyk, Tomasz S.

    2015-10-01

    A number of new platforms have been developed for multiplexed bioassays that rely on imaging targeted fluorescent beads labeled with different fluorescent dyes. We developed a compact, low-cost three-dimensional printed fluorescence microscope that can be used as a detector for mutiplexed, bead-based assays to support point-of-care applications. Images obtained with the microscope were analyzed to differentiate multiple analytes in a single sample with a comparable limit of detection to commercially available macroscopic assay platforms.

  2. Bead Based Proteome Enrichment Enhances Features of the Protein Elution Plate (PEP) for Functional Proteomic Profiling

    PubMed Central

    Wang, Xing; Davies, Michael; Roy, Swapan; Kuruc, Matthew

    2015-01-01

    A novel functional proteomics technology called PEP(Protein Elution Plate) was developed to separate complex proteomes from natural sources and analyze protein functions systematically. The technology takes advantage of the powerful resolution of two-dimensional gel electrophoresis (2-D Gels). The modification of electrophoretic conditions in combination with a high-resolution protein elution plate supports the recovery of functionally active proteins. As 2DE(2-Dimensional Electrophoresis) resolution can be limited by protein load, we investigated the use of bead based enrichment technologies, called AlbuVoid™ and KinaSorb™ to determine their effect on the proteomic features which can be generated from the PEP platform. Using a variety of substrates and enzyme activity assays, we report on the benefits of combining bead based enrichment to improve the signal report and the features generated for Hexokinase, Protein Kinase, Protease, and Alkaline Phosphatase activities. As a result, the PEP technology allows systematic analysis of large enzyme families and can build a comprehensive picture of protein function from a complex proteome, providing biological insights that could otherwise not be observed if only protein abundances were analyzed. PMID:28248280

  3. Enhancement of performance in porous bead-based microchip sensors: Effects of chip geometry on bio-agent capture

    PubMed Central

    Kulla, Eliona; Chou, Jie; Simmons, Glennon; Wong, Jorge; McRae, Michael P.; Patel, Rushi; Floriano, Pierre N.; Christodoulides, Nicolaos; Leach, Robin J.; Thompson, Ian M.; McDevitt, John T.

    2015-01-01

    Measuring low concentrations of clinically-important biomarkers using porous bead-based lab-on-a-chip (LOC) platforms is critical for the successful implementation of point-of-care (POC) devices. One way to meet this objective is to optimize the geometry of the bead holder, referred to here as a micro-container. In this work, two geometric micro-containers were explored, the inverted pyramid frustum (PF) and the inverted clipped pyramid frustum (CPF). Finite element models of this bead array assay system were developed to optimize the micro-container and bead geometries for increased pressure, to increase analyte capture in porous bead-based fluorescence immunoassays. Custom micro-milled micro-container structures containing an inverted CPF geometry resulted in a 28% reduction in flow-through regions from traditional anisotropically-etched pyramidal geometry derived from Si-111 termination layers. This novel “reduced flow-through” design resulted in a 33% increase in analyte penetration into the bead and twofold increase in fluorescence signal intensity as demonstrated with C-Reactive Protein (CRP) antigen, an important biomarker of inflammation. A consequent twofold decrease in the limit of detection (LOD) and the limit of quantification (LOQ) of a proof-of-concept assay for the free isoform of Prostate-Specific Antigen (free PSA), an important biomarker for prostate cancer detection, is also presented. Furthermore, a 53% decrease in the bead diameter is shown to result in a 160% increase in pressure and 2.5-fold increase in signal, as estimated by COMSOL models and confirmed experimentally by epi-fluorescence microscopy. Such optimizations of the bead micro-container and bead geometries have the potential to significantly reduce the LODs and reagent costs for spatially programmed bead-based assay systems of this type. PMID:26097696

  4. Sensitivity Enhancement of Bead-based Electrochemical Impedance Spectroscopy (BEIS) biosensor by electric field-focusing in microwells.

    PubMed

    Shin, Kyeong-Sik; Ji, Jae Hoon; Hwang, Kyo Seon; Jun, Seong Chan; Kang, Ji Yoon

    2016-11-15

    This paper reports a novel electrochemical impedance spectroscopy (EIS) biosensors that uses magnetic beads trapped in a microwell array to improve the sensitivity of conventional bead-based EIS (BEIS) biosensors. Unloading the previously measured beads by removing the magnetic bar enables the BEIS sensor to be used repeatedly by reloading it with new beads. Despite its recyclability, the sensitivity of conventional BEIS biosensors is so low that it has not attracted much attentions from the biosensor industry. We significantly improved the sensitivity of the BEIS system by introducing of a microwell array that contains two electrodes (a working electrode and a counter electrode) to concentrate the electric field on the surfaces of the beads. We confirmed that the performance of the BEIS sensor in a microwell array using an immunoassay of prostate specific antigen (PSA) in PBS buffer and human plasma. The experimental results showed that a low concentration of PSA (a few tens or hundreds of fg/mL) were detectable as a ratio of the changes in the impedance of the PBS buffer or in human plasma. Therefore, our BEIS sensor with a microwell array could be a promising platform for low cost, high-performance biosensors for applications that require high sensitivity and recyclability.

  5. Chaperone probes and bead-based enhancement to improve the direct detection of mRNA using silicon photonic sensor arrays.

    PubMed

    Kindt, Jared T; Bailey, Ryan C

    2012-09-18

    Herein, we describe the utility of chaperone probes and a bead-based signal enhancement strategy for the analysis of full length mRNA transcripts using arrays of silicon photonic microring resonators. Changes in the local refractive index near microring sensors associated with biomolecular binding events are transduced as a shift in the resonant wavelength supported by the cavity, enabling the sensitive analysis of numerous analytes of interest. We employ the sensing platform for both the direct and bead-enhanced detection of three different mRNA transcripts, achieving a dynamic range spanning over 4 orders of magnitude and demonstrating expression profiling capabilities in total RNA extracts from the HL-60 cell line. Small, dual-use DNA chaperone molecules were developed and found to both enhance the binding kinetics of mRNA transcripts by disrupting complex secondary structure and serve as sequence-specific linkers for subsequent bead amplification. Importantly, this approach does not require amplification of the mRNA transcript, thereby allowing for simplified analyses that do not require expensive enzymatic reagents or temperature ramping capabilities associated with RT-PCR-based methods.

  6. Single bead-based electrochemical biosensor

    PubMed Central

    Liu, Changchun; Schrlau, Michael G.; Bau, Haim H.

    2009-01-01

    A simple, robust, single bead-based electrochemical biosensor was fabricated and characterized. The sensor’s working electrode consists of an electrochemically-etched platinum wire, with a nominal diameter of 25 μm, hermetically heat-fusion sealed in a pulled glass capillary (micropipette). The sealing process does not require any epoxy or glue. A commercially available, densely functionalized agarose bead was mounted on the tip of the etched platinum wire. The use of a pre-functionalized bead eliminates the tedious and complicated surface functionalization process that is often the bottleneck in the development of electrochemical biosensors. We report on the use of a biotin agarose bead-based, micropipette, electrochemical (Bio-BMP) biosensor to monitor H2O2 concentration and the use of a streptavidin bead-based, micropipette, electrochemical (SA-BMP) biosensor to detect DNA amplicons. The Bio-BMP biosensor’s response increased linearly as the H2O2 concentration increased in the range from 1×10−6 to 1.2×10−4 M with a detection limit of 5×10−7 M. The SA-BMP was able to detect the amplicons of 1 pg DNA template of B. Cereus bacteria, thus providing better detection sensitivity than conventional gel-based electropherograms. PMID:19767195

  7. High performance wash-free magnetic bioassays through microfluidically enhanced particle specificity

    PubMed Central

    Bechstein, Daniel J.B.; Lee, Jung-Rok; Ooi, Chin Chun; Gani, Adi W.; Kim, Kyunglok; Wilson, Robert J.; Wang, Shan X.

    2015-01-01

    Magnetic biosensors have emerged as a sensitive and versatile platform for high performance medical diagnostics. These magnetic biosensors require well-tailored magnetic particles as detection probes, which need to give rise to a large and specific biological signal while showing very low nonspecific binding. This is especially important in wash-free bioassay protocols, which do not require removal of particles before measurement, often a necessity in point of care diagnostics. Here we show that magnetic interactions between magnetic particles and magnetized sensors dramatically impact particle transport and magnetic adhesion to the sensor surfaces. We investigate the dynamics of magnetic particles’ biomolecular binding and magnetic adhesion to the sensor surface using microfluidic experiments. We elucidate how flow forces can inhibit magnetic adhesion, greatly diminishing or even eliminating nonspecific signals in wash-free magnetic bioassays, and enhancing signal to noise ratios by several orders of magnitude. Our method is useful for selecting and optimizing magnetic particles for a wide range of magnetic sensor platforms. PMID:26123868

  8. High performance wash-free magnetic bioassays through microfluidically enhanced particle specificity.

    PubMed

    Bechstein, Daniel J B; Lee, Jung-Rok; Ooi, Chin Chun; Gani, Adi W; Kim, Kyunglok; Wilson, Robert J; Wang, Shan X

    2015-06-30

    Magnetic biosensors have emerged as a sensitive and versatile platform for high performance medical diagnostics. These magnetic biosensors require well-tailored magnetic particles as detection probes, which need to give rise to a large and specific biological signal while showing very low nonspecific binding. This is especially important in wash-free bioassay protocols, which do not require removal of particles before measurement, often a necessity in point of care diagnostics. Here we show that magnetic interactions between magnetic particles and magnetized sensors dramatically impact particle transport and magnetic adhesion to the sensor surfaces. We investigate the dynamics of magnetic particles' biomolecular binding and magnetic adhesion to the sensor surface using microfluidic experiments. We elucidate how flow forces can inhibit magnetic adhesion, greatly diminishing or even eliminating nonspecific signals in wash-free magnetic bioassays, and enhancing signal to noise ratios by several orders of magnitude. Our method is useful for selecting and optimizing magnetic particles for a wide range of magnetic sensor platforms.

  9. Normalization and statistical analysis of multiplexed bead-based immunoassay data using mixed-effects modeling.

    PubMed

    Clarke, David C; Morris, Melody K; Lauffenburger, Douglas A

    2013-01-01

    Multiplexed bead-based flow cytometric immunoassays are a powerful experimental tool for investigating cellular communication networks, yet their widespread adoption is limited in part by challenges in robust quantitative analysis of the measurements. Here we report our application of mixed-effects modeling for the normalization and statistical analysis of bead-based immunoassay data. Our data set consisted of bead-based immunoassay measurements of 16 phospho-proteins in lysates of HepG2 cells treated with ligands that regulate acute-phase protein secretion. Mixed-effects modeling provided estimates for the effects of both the technical and biological sources of variance, and normalization was achieved by subtracting the technical effects from the measured values. This approach allowed us to detect ligand effects on signaling with greater precision and sensitivity and to more accurately characterize the HepG2 cell signaling network using constrained fuzzy logic. Mixed-effects modeling analysis of our data was vital for ascertaining that IL-1α and TGF-α treatment increased the activities of more pathways than IL-6 and TNF-α and that TGF-α and TNF-α increased p38 MAPK and c-Jun N-terminal kinase (JNK) phospho-protein levels in a synergistic manner. Moreover, we used mixed-effects modeling-based technical effect estimates to reveal the substantial variance contributed by batch effects along with the absence of loading order and assay plate position effects. We conclude that mixed-effects modeling enabled additional insights to be gained from our data than would otherwise be possible and we discuss how this methodology can play an important role in enhancing the value of experiments employing multiplexed bead-based immunoassays.

  10. Normalization and Statistical Analysis of Multiplexed Bead-based Immunoassay Data Using Mixed-effects Modeling*

    PubMed Central

    Clarke, David C.; Morris, Melody K.; Lauffenburger, Douglas A.

    2013-01-01

    Multiplexed bead-based flow cytometric immunoassays are a powerful experimental tool for investigating cellular communication networks, yet their widespread adoption is limited in part by challenges in robust quantitative analysis of the measurements. Here we report our application of mixed-effects modeling for the normalization and statistical analysis of bead-based immunoassay data. Our data set consisted of bead-based immunoassay measurements of 16 phospho-proteins in lysates of HepG2 cells treated with ligands that regulate acute-phase protein secretion. Mixed-effects modeling provided estimates for the effects of both the technical and biological sources of variance, and normalization was achieved by subtracting the technical effects from the measured values. This approach allowed us to detect ligand effects on signaling with greater precision and sensitivity and to more accurately characterize the HepG2 cell signaling network using constrained fuzzy logic. Mixed-effects modeling analysis of our data was vital for ascertaining that IL-1α and TGF-α treatment increased the activities of more pathways than IL-6 and TNF-α and that TGF-α and TNF-α increased p38 MAPK and c-Jun N-terminal kinase (JNK) phospho-protein levels in a synergistic manner. Moreover, we used mixed-effects modeling-based technical effect estimates to reveal the substantial variance contributed by batch effects along with the absence of loading order and assay plate position effects. We conclude that mixed-effects modeling enabled additional insights to be gained from our data than would otherwise be possible and we discuss how this methodology can play an important role in enhancing the value of experiments employing multiplexed bead-based immunoassays. PMID:23071098

  11. Properties of coatings on RFID p-Chips that support plasmonic fluorescence enhancement in bioassays

    PubMed Central

    Rich, Ryan; Li, Ji; Fudala, Rafal; Gryczynski, Zygmunt; Gryczynski, Ignacy; Mandecki, Wlodek

    2012-01-01

    Microtransponders (RFID p-Chips) derivatized with silver island film (SIF) have previously seen success as a platform for the quantification of low-abundance biomolecules in nucleic acid-based assays and immunoassays. In this study, we further characterized the morphology of the SIF as well as the polymer matrix enveloping it by scanning electron microscopy (SEM). The polymer was a two-layer silane-based matrix engulfing the p-Chip and SIF. Through a series of SEM and confocal fluorescence microscopy experiments we found the depth of the polymer matrix to be 1–2 µm. The radiative effects of the SIF/polymer layer were assessed by fluorescence lifetime imaging (FLIM) of p-Chips coated with the polymer to which a fluorophore (Alexa Fluor 555) was conjugated. FLIM images showed an 8.7-fold increase in fluorescence intensity and an increased rate of radiative decay, the latter of which is associated with improved photostability and both of which are linked to plasmonic enhancement by the SIF. Plasmonic enhancement was found to extend uniformly across the p-Chip and, interestingly, to a depth of about 1.2 µm. The substantial depth of enhancement suggests that the SIF/polymer layer constitutes a three-dimensional matrix that is accessible to solvent and small molecules such as fluorescent dyes. Finally, we confirmed that no surface-enhanced Raman scattering (SERS) is seen from the SIF/polymer combination. The analysis provides a possible mechanism by which the SIF/polymer-coated p-Chips allow a highly sensitive immunoassay and, as a result, leads to an improved bioassay platform. PMID:22960796

  12. Properties of coatings on RFID p-Chips that support plasmonic fluorescence enhancement in bioassays.

    PubMed

    Rich, Ryan; Li, Ji; Fudala, Rafal; Gryczynski, Zygmunt; Gryczynski, Ignacy; Mandecki, Wlodek

    2012-11-01

    Microtransponders (RFID p-Chips) derivatized with silver island film (SIF) have previously seen success as a platform for the quantification of low-abundance biomolecules in nucleic acid based assays and immunoassays. In this study, we further characterized the morphology of the SIF as well as the polymer matrix enveloping it by scanning electron microscopy (SEM). The polymer was a two-layer silane-based matrix engulfing the p-Chip and SIF. Through a series of SEM and confocal fluorescence microscopy experiments, we found the depth of the polymer matrix to be 1-2 μm. The radiative effects of the SIF/polymer layer were assessed by fluorescence lifetime imaging (FLIM) of p-Chips coated with the polymer to which a fluorophore (Alexa Fluor 555) was conjugated. FLIM images showed an 8.7-fold increase in fluorescence intensity and an increased rate of radiative decay, the latter of which is associated with improved photostability and both of which are linked to plasmonic enhancement by the SIF. Plasmonic enhancement was found to extend uniformly across the p-Chip and, interestingly, to a depth of about 1.2 μm. The substantial depth of enhancement suggests that the SIF/polymer layer constitutes a three-dimensional matrix that is accessible to solvent and small molecules such as fluorescent dyes. Finally, we confirmed that no surface-enhanced Raman scattering is seen from the SIF/polymer combination. The analysis provides a possible mechanism by which the SIF/polymer-coated p-Chips allow a highly sensitive immunoassay and, as a result, leads to an improved bioassay platform.

  13. Chip-Scale Bioassays Based on Surface-Enhanced Raman Scattering: Fundamentals and Applications

    SciTech Connect

    Park, Hye-Young

    2005-01-01

    This work explores the development and application of chip-scale bioassays based on surface-enhanced Raman scattering (SERS) for high throughput and high sensitivity analysis of biomolecules. The size effect of gold nanoparticles on the intensity of SERS is first presented. A sandwich immunoassay was performed using Raman-labeled immunogold nanoparticles with various sizes. The SERS responses were correlated to particle densities, which were obtained by atomic force microscopy (AFM). The response of individual particles was also investigated using Raman-microscope and an array of gold islands on a silicon substrate. The location and the size of individual particles were mapped using AFM. The next study describes a low-level detection of Escherichia coli 0157:H7 and simulants of biological warfare agents in a sandwich immunoassay format using SERS labels, which have been termed Extrinsic Raman labels (ERLs). A new ERL scheme based on a mixed monolayer is also introduced. The mixed monolayer ERLs were created by covering the gold nanoparticles with a mixture of two thiolates, one thiolate for covalently binding antibody to the particle and the other thiolate for producing a strong Raman signal. An assay platform based on mixed self-assembled monolayers (SAMs) on gold is then presented. The mixed SAMs were prepared from dithiobis(succinimidyl undecanoate) (DSU) to covalently bind antibodies on gold substrate and oligo(ethylene glycol)-terminated thiol to prevent nonspecific adsorption of antibodies. After the mixed SAMs surfaces, formed from various mole fraction of DSU were incubated with antibodies, AFM was used to image individual antibodies on the surface. The final study presents a collaborative work on the single molecule adsorption of YOYO-I labeled {lambda}-DNA at compositionally patterned SAMs using total internal reflection fluorescence microscopy. The role of solution pH, {lambda}-DNA concentration, and domain size was investigated. This work also revealed

  14. Bead-based microfluidic immunoassay for diagnosis of Johne's disease

    SciTech Connect

    Wadhwa, Ashutosh; Foote, Robert; Shaw, Robert W; Eda, Shigetoshi

    2012-01-01

    Microfluidics technology offers a platform for development of point-of-care diagnostic devices for various infectious diseases. In this study, we examined whether serodiagnosis of Johne s disease (JD) can be conducted in a bead-based microfluidic assay system. Magnetic micro-beads were coated with antigens of the causative agent of JD, Mycobacterium avium subsp. paratuberculosis. The antigen-coated beads were incubated with serum samples of JD-positive or negative serum samples and then with a fluorescently-labeled secondary antibody (SAB). To confirm binding of serum antibodies to the antigen, the beads were subjected to flow cytometric analysis. Different conditions (dilutions of serum and SAB, types of SAB, and types of magnetic beads) were optimized for a great degree of differentiation between the JD-negative and JD-positive samples. Using the optimized conditions, we tested a well-classified set of 155 serum samples from JD negative and JD-positive cattle by using the bead-based flow cytometric assay. Of 105 JD-positive samples, 63 samples (60%) showed higher antibody binding levels than a cut-off value determined by using antibody binding levels of JD-negative samples. In contrast, only 43-49 JD-positive samples showed higher antibody binding levels than the cut-off value when the samples were tested by commercially-available immunoassays. Microfluidic assays were performed by magnetically immobilizing a number of beads within a microchannel of a glass microchip and detecting antibody on the collected beads by laser-induced fluorescence. Antigen-coated magnetic beads treated with bovine serum sample and fluorescently-labeled SAB were loaded into a microchannel to measure the fluorescence (reflecting level of antibody binding) on the beads in the microfluidic system. When the results of five bovine serum samples obtained with the system were compared to those obtained with the flow cytometer, a high level of correlation (linear regression, r2 = 0.994) was

  15. A dynamic bead-based microarray for parallel DNA detection

    NASA Astrophysics Data System (ADS)

    Sochol, R. D.; Casavant, B. P.; Dueck, M. E.; Lee, L. P.; Lin, L.

    2011-05-01

    A microfluidic system has been designed and constructed by means of micromachining processes to integrate both microfluidic mixing of mobile microbeads and hydrodynamic microbead arraying capabilities on a single chip to simultaneously detect multiple bio-molecules. The prototype system has four parallel reaction chambers, which include microchannels of 18 × 50 µm2 cross-sectional area and a microfluidic mixing section of 22 cm length. Parallel detection of multiple DNA oligonucleotide sequences was achieved via molecular beacon probes immobilized on polystyrene microbeads of 16 µm diameter. Experimental results show quantitative detection of three distinct DNA oligonucleotide sequences from the Hepatitis C viral (HCV) genome with single base-pair mismatch specificity. Our dynamic bead-based microarray offers an effective microfluidic platform to increase parallelization of reactions and improve microbead handling for various biological applications, including bio-molecule detection, medical diagnostics and drug screening.

  16. Enhanced red-emitting railroad worm luciferase for bioassays and bioimaging.

    PubMed

    Li, Xueyan; Nakajima, Yoshihiro; Niwa, Kazuki; Viviani, Vadim R; Ohmiya, Yoshihiro

    2010-01-01

    A luciferase from the railroad worm (Phrixothrix hirtus) is the only red-emitting bioluminescent enzyme in nature that is advantageous in multicolor luciferase assays and in bioluminescence imaging (BLI). However, it is not used widely in scientific or industrial applications because of its low activity and stability. By using site-directed mutagenesis, we produced red-emitting mutants with higher activity and better stability. Compared with the wild-type (WT), the luminescent activities from extracts of cultured mammalian cells expressing mutant luciferase were 9.8-fold in I212L/N351K, 8.4-fold in I212L, and 7.8-fold in I212L/S463R; and the cell-based activities were 3.6-fold in I212L/N351K and 3.4-fold in N351K. The remaining activities after incubation at 37 degrees C for 10 min were 50.0% for I212L/S463R, 31.8% for I212L, and 23.0% for I212L/N351K, but only 5.2% for WT. To demonstrate an application of I212L/N351K, cell-based BLI was performed, and the luminescence signal was 3.6-fold higher than in WT. These results indicate that the mutants might improve the practicability of this signaling in bioassays and BLI.

  17. Label-free bead-based metallothionein electrochemical immunosensor.

    PubMed

    Nejdl, Lukas; Nguyen, Hoai Viet; Richtera, Lukas; Krizkova, Sona; Guran, Roman; Masarik, Michal; Hynek, David; Heger, Zbynek; Lundberg, Karin; Erikson, Kristofer; Adam, Vojtech; Kizek, Rene

    2015-08-01

    A novel microfluidic label-free bead-based metallothionein immunosensors was designed. To the surface of superparamagnetic agarose beads coated with protein A, polyclonal chicken IgY specifically recognizing metallothionein (MT) were immobilized via rabbit IgG. The Brdicka reaction was used for metallothionein detection in a microfluidic printed 3D chip. The assembled chip consisted of a single copper wire coated with a thin layer of amalgam as working electrode. Optimization of MT detection using designed microfluidic chip was performed in stationary system as well as in the flow arrangement at various flow rates (0-1800 μL/min). In stationary arrangement it is possible to detect MT concentrations up to 30 ng/mL level, flow arrangement allows reliable detection of even lower concentration (12.5 ng/mL). The assembled miniature flow chip was subsequently tested for the detection of MT elevated levels (at approx. level 100 μg/mL) in samples of patients with cancer. The stability of constructed device for metallothionein detection in flow arrangement was found to be several days without any maintenance needed.

  18. Rapid Bead-Based Antimicrobial Susceptibility Testing by Optical Diffusometry

    PubMed Central

    Chung, Chih-Yao; Wang, Jhih-Cheng; Chuang, Han-Sheng

    2016-01-01

    This study combined optical diffusometry and bead-based immunoassays to develop a novel technique for quantifying the growth of specific microorganisms and achieving rapid AST. Diffusivity rises when live bacteria attach to particles, resulting in additional energy from motile microorganisms. However, when UV-sterilized (dead) bacteria attach to particles, diffusivity declines. The experimental data are consistent with the theoretical model predicted according to the equivalent volume diameter. Using this diffusometric platform, the susceptibility of Pseudomonas aeruginosa to the antibiotic gentamicin was tested. The result suggests that the proliferation of bacteria is effectively controlled by gentamicin. This study demonstrated a sensitive (one bacterium on single particles) and time-saving (within 2 h) platform with a small sample volume (~0.5 μL) and a low initial bacteria count (50 CFU per droplet ~ 105 CFU/mL) for quantifying the growth of microorganisms depending on Brownian motion. The technique can be applied further to other bacterial strains and increase the success of treatments against infectious diseases in the near future. PMID:26863001

  19. Increased bioassay sensitivity of bioactive molecule discovery using metal-enhanced bioluminescence

    NASA Astrophysics Data System (ADS)

    Golberg, Karina; Elbaz, Amit; McNeil, Ronald; Kushmaro, Ariel; Geddes, Chris D.; Marks, Robert S.

    2014-12-01

    We report the use of bioluminescence signal enhancement via proximity to deposited silver nanoparticles for bioactive compound discovery. This approach employs a whole-cell bioreporter harboring a plasmid-borne fusion of a specific promoter incorporated with a bioluminescence reporter gene. The silver deposition process was first optimized to provide optimal nanoparticle size in the reaction time dependence with fluorescein. The use of silver deposition of 350 nm particles enabled the doubling of the bioluminescent signal amplitude by the bacterial bioreporter when compared to an untouched non-silver-deposited microtiter plate surface. This recording is carried out in the less optimal but necessary far-field distance. SEM micrographs provided a visualization of the proximity of the bioreporter to the silver nanoparticles. The electromagnetic field distributions around the nanoparticles were simulated using Finite Difference Time Domain, further suggesting a re-excitation of non-chemically excited bioluminescence in addition to metal-enhanced bioluminescence. The possibility of an antiseptic silver effect caused by such a close proximity was eliminated disregarded by the dynamic growth curves of the bioreporter strains as seen using viability staining. As a highly attractive biotechnology tool, this silver deposition technique, coupled with whole-cell sensing, enables increased bioluminescence sensitivity, making it especially useful for cases in which reporter luminescence signals are very weak.

  20. Chloramphenicol bioassay.

    PubMed

    Bannatyne, R M; Cheung, R

    1979-07-01

    An accurate plate diffusion bioassay for chloramphenicol is described, in which the fast-replicating Beneckea natriegens and 1.5% salt agar are used. Zones of inhibition were well defined after 3 h, and the limit of sensitivity of the method was around 2 mug/ml. The concurrent presence of gentamicin did not influence the assay. The assay is simple to carry out and duplicate assays can be performed with as little as 100 mug of capillary blood.

  1. Ticarcillin bioassay.

    PubMed

    Bannatyne, R M; Cheung, R

    1981-10-01

    An accurate, plate diffusion bioassay for ticarcillin, utilizing the fast-replicating Beneckea natriegens and 4% salt agar, is described in this report. Zones of inhibition were well defined after 3 h, and the limit of sensitivity was around 5.0 mug/ml. The assay is simple to carry out, and duplicate assays can be performed on as little as 40 mul of serum.

  2. Metal-enhanced intrinsic fluorescence of proteins and label-free bioassays

    NASA Astrophysics Data System (ADS)

    Ray, Krishanu; Szmacinski, Henryk; Chowdhury, Mustafa H.; Lakowicz, Joseph R.

    2010-02-01

    Most of the applications of fluorescence require the use of labeled drugs and labeled biomolecules. Due to the need of labeling biomolecules with extrinsic fluorophores, there is a rapidly growing interest in methods which provide label-free detection (LFD). Proteins are highly fluorescent, which is due primarily to tryptophan residues. However, since most proteins contain tryptophan, this emission is not specific for proteins of interest in a biological sample. This is one of the reasons of not utilizing intrinsic tryptophan emission from proteins to detect specific proteins. Here, we present the intrinsic fluorescence for several proteins bound to the silver or aluminum metal nanostructured surfaces. We demonstrate the metal enhanced fluorescence (MEF) of proteins with different numbers of tryptophan residues. Large increases in fluorescence intensity and decreases in lifetime provide the means of direct detection of bound protein without separation from the unbound. We present specific detection of individual types of proteins and measure the binding kinetics of proteins such as IgG and streptavidin. Additionally, specific detection of IgG and streptavidin has been accomplished in the presence of large concentrations of other proteins in sample solutions. These results will allow design of surface-based assays with biorecognitive layer that specifically bind the protein of interest and thus enhance its intrinsic fluorescence. The present study demonstrates the occurrence of MEF in the UV region and thus opens new possibilities to study tryptophan-containing proteins without labeling with longer wavelength fluorophores and provides an approach to label-free detection of biomolecules.

  3. Development of nanoparticle applications in cell imaging, bioassay and reactive oxygen species detection based on surface-enhanced raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Huang, Yiming

    Surface-enhanced Raman scattering (SERS) has been developed over forty years with a wide variety of applications. Signals enhanced from single molecule absorbed on the surface of metallic nanoparticles can be up to 14-order-of-magnitude. This is due to the resonance between the optical field and surface plasmon of the metal substrate. Nanoshells have been chosen as substrates since they do not need to pre-aggregate due to their tunable optical property. We developed Raman imaging system by incorporating functionalized nanoshells, cells and SERS. Nanoshells have been coated with different self-assembled monolayers containing poly(ethylene glycol) (PEG) molecules. Probes have been designed by coating nanoshells with Raman active PEG molecules and delivered into macrophage cells. The imaging technique requires less preparation and provides the information of nanoshells in semi-quantitative way in vitro. We developed half-sandwich bioassay by detecting low volume of antigens on nitrocellulose membrane, detected by SERS. Antibodies were grafted to the surface of nanoshells and were conjugated to the antigens on the nitrocellulose membrane for detection. Raman active PEGs were conjugated onto the metal substrate for recognition and quantification. The benefits of this assay are that it is faster, easier to execute and requires less volume of antigen to conjugate onto the substrate. We also developed reactive oxygen species (ROS) sensors by incubating PEGs and either 4-nitrobenzenethiol (4-NBT) or 4-mercaptophenol (4-MP) on the surface of nanoshells. By analyzing the changes of SERS spectrum, the production of hydroxyl radicals produced in the Fenton reaction can be tracked in low concentrations. The sensors were designed to track ROS production within cells when they are under oxidative stress. The methods developed in this thesis are versatile, and can be broadly applied to the study of different subtracts, such as gold colloid.

  4. Magnetic Beads-based Bioelectrochemical Immunoassay of Polycyclic Aromatic Hydrocarbons

    SciTech Connect

    Lin, Ying-Ying; Liu, Guodong; Wai, Chien M.; Lin, Yuehe

    2007-07-01

    A simple, rapid, and sensitive bioelectrochemical immunoassay method based on magnetic beads (MBs) has been developed to detect polycyclic aromatic hydrocarbons (PAHs). The principle of this bioassay is based on a direct competitive enzyme-linked immunosorbent assay using PAH-antibody-coated MBs and horseradish peroxidase (HRP)-labeled PAH (HRP-PAH). A magnetic process platform was used to mix and shake the samples during the immunoreactions and to separate free and unbound reagents after the liquid-phase competitive immunoreaction among PAH-antibody-coated MBs, PAH analyte, and HRP-PAH. After a complete immunoassay, the HRP tracers attached to MBs were transferred to a substrate solution containing 3, 3´, 5, 5´- tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2) for electrochemical detection. The voltammetric characteristics of the substrate were investigated, and the reduction peak current of TMB was used to quantify the concentration of PAH. The different parameters, including the amount of HRP-PAH conjugates, the enzyme catalytic reaction time, and the pH of the supporting electrolyte that governs the analytical performance of the immunoassay have been studied in detail and optimized. The detection limit of 50 pg mL-1 was obtained under optimum experimental conditions. The performance of this bioelectrochemical magnetic immunoassay was successfully evaluated with tap water spiked with PAHs, indicating that this convenient and sensitive technique offers great promise for decentralized environmental applications.

  5. Multiplexed bead-based mesofluidic system for gene diagnosis and genotyping.

    PubMed

    Jin, Sheng-Quan; Ye, Bang-Ce; Huo, Hao; Zeng, Ai-Jun; Xie, Cheng-Ke; Ren, Bing-Qiang; Huang, Hui-Jie

    2010-12-01

    We have developed a novel multiplexed bead-based mesofluidic system (MBMS) based on the specific recognition events on the surface of a series of microbeads (diameter 250 μm) arranged in polydimethylsiloxane (PDMS) microchannels (diameter 300 μm) with the predetermined order and assembled an apparatus implementing automatically the high-throughput bead-based assay and further demonstrated its feasibility and flexibility of gene diagnosis and genotyping, such as β-thalassemia mutation detection and HLA-DQA genotyping. The apparatus, consisting of bead-based mesofluidic PDMS chip, liquid-processing module, and fluorescence detection module, can integrate the procedure of automated-sampling, hybridization reactions, washing, and in situ fluorescence detection. The results revealed that MBMS is fast, has high sensitivity, and can be automated to carry out parallel and multiplexed genotyping and has the potential to open up new routes to flexible, high-throughput approaches for bioanalysis.

  6. Fine-tuning of magnetic and microfluidic viscous forces for specific magnetic bead-based immunocomplex formation

    NASA Astrophysics Data System (ADS)

    Cornaglia, M.; Tekin, H. C.; Lehnert, T.; Gijs, M. A. M.

    2013-08-01

    We investigate the working principle of a novel type of microfluidic sandwich immunoassay, as used for the detection of biomarkers. The heterogeneous assay is based on the specific interactions between an array of functionalized superparamagnetic beads and a flow of secondary superparamagnetic beads that carry the antigens and are simultaneously used as detection labels. We identify the main forces governing the immunoassay performance and develop a combined finite element method/analytical model to predict and control these forces. The clue for the improved assay specificity is in the fine-tuning of inter-bead magnetic dipolar and microfluidic viscous forces, which allows strongly reducing non-specific interactions, while enhancing the specific formation of immunocomplexes. We exploit our theoretical model to explain the enhanced sensitivity of magnetic bead-based immunoassay experiments performed in microfluidic chips.

  7. Detection of low-abundance biomarker lipocalin 1 for diabetic retinopathy using optoelectrokinetic bead-based immunosensing.

    PubMed

    Wang, Jhih-Cheng; Ku, Hu-Yao; Chen, Tain-Song; Chuang, Han-Sheng

    2017-03-15

    Early diagnosis of diabetic retinopathy (DR) is vital but challenging. DR is a common complication and a major cause of vision loss in patients with diabetes mellitus. Without appropriate medical intervention, visual impairment may become a great burden to our healthcare system. In clinical practice, the current diagnostic methods, such as fluorescence angiography and optical coherence tomography, remain constrained by non-quantitative examinations and individual ophthalmologists' experiences. Late diagnosis often prevents early treatment. To address the constraints on current diagnostics, this study developed an optoelectrokinetic bead-based immunosensing technique for detecting lipocalin 1 (LCN1), a DR biomarker. The concentration level of LCN1 in the tears of DR patients increases with DR severity. The immunoassay was dependent on the formation of sandwiched immunocomplexes on the particles. A secondary antibody labeled with dyes/quantum dots (QDs) was used to visualize the presence of the target antigens. Rapid electrokinetic patterning (REP), an optoelectrokinetic technique, was used to dynamically enhance the fluorescent signal by concentrating the modified particles. The limit of detection (LOD) of the technique could reach 110pg/mL. Only 1.5μL of a sample fluid was required for the measurement. Our results showed that highly sensitive and improved LOD is subjected to particle stacking, small particle size, and compact cluster. By labeling different particle sizes with dyes/QDs for LCN1 and TNF-α, we successfully used REP to detect the two DR biomarkers on the same platform. The development of an optoelectrokinetic bead-based immunosensing technique can provide new insights into diagnosing other low-abundance diseases in the future.

  8. An integrated microfluidic biochemical detection system for protein analysis with magnetic bead-based sampling capabilities.

    PubMed

    Choi, Jin-Woo; Oh, Kwang W; Thomas, Jennifer H; Heineman, William R; Halsall, H Brian; Nevin, Joseph H; Helmicki, Arthur J; Henderson, H Thurman; Ahn, Chong H

    2002-02-01

    This paper presents the development and characterization of an integrated microfluidic biochemical detection system for fast and low-volume immunoassays using magnetic beads, which are used as both immobilization surfaces and bio-molecule carriers. Microfluidic components have been developed and integrated to construct a microfluidic biochemical detection system. Magnetic bead-based immunoassay, as a typical example of biochemical detection and analysis, has been successfully performed on the integrated microfluidic biochemical analysis system that includes a surface-mounted biofilter and electrochemical sensor on a glass microfluidic motherboard. Total time required for an immunoassay was less than 20 min including sample incubation time, and sample volume wasted was less than 50 microl during five repeated assays. Fast and low-volume biochemical analysis has been successfully achieved with the developed biofilter and immunosensor, which is integrated to the microfluidic system. Such a magnetic bead-based biochemical detection system, described in this paper, can be applied to protein analysis systems.

  9. Developing Enhanced Blood–Brain Barrier Permeability Models: Integrating External Bio-Assay Data in QSAR Modeling

    PubMed Central

    Wang, Wenyi; Kim, Marlene T.; Sedykh, Alexander

    2015-01-01

    Purpose Experimental Blood–Brain Barrier (BBB) permeability models for drug molecules are expensive and time-consuming. As alternative methods, several traditional Quantitative Structure-Activity Relationship (QSAR) models have been developed previously. In this study, we aimed to improve the predictivity of traditional QSAR BBB permeability models by employing relevant public bio-assay data in the modeling process. Methods We compiled a BBB permeability database consisting of 439 unique compounds from various resources. The database was split into a modeling set of 341 compounds and a validation set of 98 compounds. Consensus QSAR modeling workflow was employed on the modeling set to develop various QSAR models. A five-fold cross-validation approach was used to validate the developed models, and the resulting models were used to predict the external validation set compounds. Furthermore, we used previously published membrane transporter models to generate relevant transporter profiles for target compounds. The transporter profiles were used as additional biological descriptors to develop hybrid QSAR BBB models. Results The consensus QSAR models have R2=0.638 for fivefold cross-validation and R2=0.504 for external validation. The consensus model developed by pooling chemical and transporter descriptors showed better predictivity (R2=0.646 for five-fold cross-validation and R2=0.526 for external validation). Moreover, several external bio-assays that correlate with BBB permeability were identified using our automatic profiling tool. Conclusions The BBB permeability models developed in this study can be useful for early evaluation of new compounds (e.g., new drug candidates). The combination of chemical and biological descriptors shows a promising direction to improve the current traditional QSAR models. PMID:25862462

  10. Confirming Pseudomonas putida as a reliable bioassay for demonstrating biocompatibility enhancement by solar photo-oxidative processes of a biorecalcitrant effluent.

    PubMed

    García-Ripoll, A; Amat, A M; Arques, A; Vicente, R; Ballesteros Martín, M M; Pérez, J A Sánchez; Oller, I; Malato, S

    2009-03-15

    Experiments based on Vibrio fischeri, activated sludge and Pseudomonas putida have been employed to check variation in the biocompatibility of an aqueous solution of a commercial pesticide, along solar photo-oxidative process (TiO(2) and Fenton reagent). Activated sludge-based experiments have demonstrated a complete detoxification of the solution, although important toxicity is still detected according to the more sensitive V. fischeri assays. In parallel, the biodegradability of organic matter is strongly enhanced, with BOD(5)/COD ratio above 0.8. Bioassays run with P. putida have given similar trends, remarking the convenience of using P. putida culture as a reliable and reproducible method for assessing both toxicity and biodegradability, as a substitute to other more time consuming methods.

  11. Magnetic actuator for the control and mixing of magnetic bead-based reactions on-chip.

    PubMed

    Berenguel-Alonso, Miguel; Granados, Xavier; Faraudo, Jordi; Alonso-Chamarro, Julián; Puyol, Mar

    2014-10-01

    While magnetic bead (MB)-based bioassays have been implemented in integrated devices, their handling on-chip is normally either not optimal--i.e. only trapping is achieved, with aggregation of the beads--or requires complex actuator systems. Herein, we describe a simple and low-cost magnetic actuator to trap and move MBs within a microfluidic chamber in order to enhance the mixing of a MB-based reaction. The magnetic actuator consists of a CD-shaped plastic unit with an arrangement of embedded magnets which, when rotating, generate the mixing. The magnetic actuator has been used to enhance the amplification reaction of an enzyme-linked fluorescence immunoassay to detect Escherichia coli O157:H7 whole cells, an enterohemorrhagic strain, which have caused several outbreaks in food and water samples. A 2.7-fold sensitivity enhancement was attained with a detection limit of 603 colony-forming units (CFU) /mL, when employing the magnetic actuator.

  12. Development of a bead-based suspension array for the detection of pathogens in acute respiratory tract infections

    PubMed Central

    Li, Hong-Ru; Zhang, Wei; Hua, Zhi-Dan; Lin, Xiao-Hong; Lin, Meng-Qing; Huang, Wen-Sen; Huang, Li-Ping; Yu, Xiao-Li; Xu, Neng-Luan; Lin, Ming; Xie, Bao-Song; Shen, Xiao-Na; Xie, Jian-Feng; Wang, Yi; Huang, Meng; Wu, Yan-An; Hu, Xin-Lan

    2016-01-01

    We developed a high-throughput bead-based suspension array for simultaneous detection of 20 respiratory tract pathogens in clinical specimens. Pathogen-specific genes were amplified and hybridized to probes coupled to carboxyl-encoded microspheres. Fluorescence intensities generated via the binding of phycoerythrin-conjugated streptavidin with biotin-labeled targets were measured by the Luminex 100 bead-based suspension array system. The bead-based suspension array detected bacteria in a significantly higher number of samples compared to the conventional culture. There was no significant difference in the detection rate of atypical pathogensatypical pathogens or viruses between the bead-based suspension array and real-time PCR. This technology can play a significant role in screening patients with pneumonia. PMID:27190247

  13. Bead-based competitive fluorescence immunoassay for sensitive and rapid diagnosis of cyanotoxin risk in drinking water.

    PubMed

    Yu, Hye-Weon; Jang, Am; Kim, Lan Hee; Kim, Sung-Jo; Kim, In S

    2011-09-15

    Due to the increased occurrence of cyanobacterial blooms and their toxins in drinking water sources, effective management based on a sensitive and rapid analytical method is in high demand for security of safe water sources and environmental human health. Here, a competitive fluorescence immunoassay of microcystin-LR (MCYST-LR) is developed in an attempt to improve the sensitivity, analysis time, and ease-of-manipulation of analysis. To serve this aim, a bead-based suspension assay was introduced based on two major sensing elements: an antibody-conjugated quantum dot (QD) detection probe and an antigen-immobilized magnetic bead (MB) competitor. The assay was composed of three steps: the competitive immunological reaction of QD detection probes against analytes and MB competitors, magnetic separation and washing, and the optical signal generation of QDs. The fluorescence intensity was found to be inversely proportional to the MCYST-LR concentration. Under optimized conditions, the proposed assay performed well for the identification and quantitative analysis of MCYST-LR (within 30 min in the range of 0.42-25 μg/L, with a limit of detection of 0.03 μg/L). It is thus expected that this enhanced assay can contribute both to the sensitive and rapid diagnosis of cyanotoxin risk in drinking water and effective management procedures.

  14. A Magnetic Bead-Based Sensor for the Quantification of Multiple Prostate Cancer Biomarkers

    PubMed Central

    Jokerst, Jesse V.; Chen, Zuxiong; Xu, Lingyun; Nolley, Rosalie; Chang, Edwin; Mitchell, Breeana; Brooks, James D.; Gambhir, Sanjiv S.

    2015-01-01

    Novel biomarker assays and upgraded analytical tools are urgently needed to accurately discriminate benign prostatic hypertrophy (BPH) from prostate cancer (CaP). To address this unmet clinical need, we report a piezeoelectric/magnetic bead-based assay to quantitate prostate specific antigen (PSA; free and total), prostatic acid phosphatase, carbonic anhydrase 1 (CA1), osteonectin, IL-6 soluble receptor (IL-6sr), and spondin-2. We used the sensor to measure these seven proteins in serum samples from 120 benign prostate hypertrophy patients and 100 Gleason score 6 and 7 CaP using serum samples previously collected and banked. The results were analyzed with receiver operator characteristic curve analysis. There were significant differences between BPH and CaP patients in the PSA, CA1, and spondin-2 assays. The highest AUC discrimination was achieved with a spondin-2 OR free/total PSA operation—the area under the curve was 0.84 with a p value below 10−6. Some of these data seem to contradict previous reports and highlight the importance of sample selection and proper assay building in the development of biomarker measurement schemes. This bead-based system offers important advantages in assay building including low cost, high throughput, and rapid identification of an optimal matched antibody pair. PMID:26421725

  15. Five-Antigen Fluorescent Bead-Based Assay for Diagnosis of Lyme Disease

    PubMed Central

    Hasenkampf, Nicole R.; Barnes, Mary B.; Didier, Elizabeth S.; Philipp, Mario T.; Tardo, Amanda C.

    2016-01-01

    The systematically difficult task of diagnosing Lyme disease can be simplified by sensitive and specific laboratory tests. The currently recommended two-tier test for serology is highly specific but falls short in sensitivity, especially in the early acute phase. We previously examined serially collected serum samples from Borrelia burgdorferi-infected rhesus macaques and defined a combination of antigens that could be utilized for detection of infection at all phases of disease in humans. The five B. burgdorferi antigens, consisting of OspC, OspA, DbpA, OppA2, and the C6 peptide, were combined into a fluorescent cytometric bead-based assay for the detection of B. burgdorferi antigen-specific IgG antibodies. Samples from Lyme disease patients and controls were used to determine the diagnostic value of this assay. Using this sample set, we found that our five-antigen multiplex IgG assay exhibited higher sensitivity (79.5%) than the enzyme immunoassay (EIA) (76.1%), the two-tier test (61.4%), and the C6 peptide enzyme-linked immunosorbent assay (ELISA) (77.2%) while maintaining specificity over 90%. When detection of IgM was added to the bead-based assay, the sensitivity improved to 91%, but at a cost of reduced specificity (78%). These results indicate that the rational combination of antigens in our multiplex assay may offer an improved serodiagnostic test for Lyme disease. PMID:26843487

  16. Novel bead-based platform for direct detection of unlabelled nucleic acids through Single Nucleobase Labelling.

    PubMed

    Venkateswaran, Seshasailam; Luque-González, Maria Angélica; Tabraue-Chávez, Mavys; Fara, Mario Antonio; López-Longarela, Barbara; Cano-Cortes, Victoria; López-Delgado, Francisco Javier; Sánchez-Martín, Rosario María; Ilyine, Hugh; Bradley, Mark; Pernagallo, Salvatore; Díaz-Mochón, Juan José

    2016-12-01

    Over the last decade, circulating microRNAs have received attention as diagnostic and prognostic biomarkers. In particular, microRNA122 has been demonstrated to be an early and more sensitive indicator of drug-induced liver injury than the widely used biomarkers such as alanine aminotransferase and aspartate aminotransferase. Recently, microRNA122 has been used in vitro to assess the cellular toxicity of new drugs and as a biomarker for the development of a rapid test for drug overdose/liver damage. In this proof-of-concept study, we report a PCR-free and label-free detection method that has a limit of detection (3 standard deviations) of 15 fmoles of microRNA122, by integrating a dynamic chemical approach for "Single Nucleobase Labelling" with a bead-based platform (Luminex(®)) thereby, in principle, demonstrating the exciting prospect of rapid and accurate profiling of any microRNAs related to diseases and toxicology.

  17. High Throughput Flow Cytometry Bead-based Multiplex Assay for Identification of Rho GTPase Inhibitors

    PubMed Central

    Surviladze, Zurab; Young, Susan M; Sklar, Larry A

    2015-01-01

    Summary Rho family GTPases and their effector proteins regulate a wide range of cell signaling pathways. In normal physiological conditions their activity is tightly controlled and it is not surprising that their aberrant activation contributes to tumorigenesis or other diseases. For this reason, the identification of small, cell permeable molecules capable of inhibition of Rho GTPases can be extraordinarily useful, particularly if they are specific and act reversibly. Herein we describe a flow cytometric assay, which allows us to measure the activity of six small GTPases simultaneously. GST-tagged small GTPases are bound to six glutathione bead sets each set having a different intensity of red fluorescence at a fixed wavelength. The coated bead sets were washed, combined, and dispensed into 384-well plates with test compounds, and fluorescent-GTP binding was used as the read-out. This multiplex bead-based assay was successfully used for to identify both general and selective inhibitors of Rho family GTPases. PMID:22144280

  18. Magnetic bead-based nucleic acid purification kit: Clinical application and performance evaluation in stool specimens.

    PubMed

    Yoon, Jihoon G; Kang, Jin Seok; Hwang, Seung Yong; Song, Jaewoo; Jeong, Seok Hoon

    2016-05-01

    Two different methods - the semi-automated magnetic bead-based kit (SK, Stool DNA/RNA Purification kit®) and the manual membrane column-based kit (QS, QIAamp® DNA Stool Mini kit) - for purifying nucleic acids from clinical stool samples were compared and evaluated. The SK kit was more user-friendly than QS due to the reduced manual processing, partial automation, and short turnaround time with half cost. Furthermore, SK produced high yields in both DNA and RNA extractions but poor purity in RNA extraction. In the assessment of rotavirus and Clostridium difficile infection, both kits had equivalent or more sensitive performance compared with the standard method. Although SK showed some interference and inhibition in nucleic acid extraction, the performance, including the repeatability, linearity, analytical sensitivity, and matrix effect, was sufficient for routine clinical use.

  19. A reliable and sensitive bead-based fluorescence assay for identification of nucleic acid sequences

    NASA Astrophysics Data System (ADS)

    Klamp, Tobias; Yahiatène, Idir; Lampe, André; Schüttpelz, Mark; Sauer, Markus

    2011-03-01

    The sensitive and rapid detection of pathogenic DNA is of tremendous importance in the field of diagnostics. We demonstrate the ability of detecting and quantifying single- and double-stranded pathogenic DNA with picomolar sensitivity in a bead-based fluorescence assay. Selecting appropriate capturing and detection sequences enables rapid (2 h) and reliable DNA quantification. We show that synthetic sequences of S. pneumoniae and M. luteus can be quantified in very small sample volumes (20 μL) across a linear detection range over four orders of magnitude from 1 nM to 1 pM, using a miniaturized wide-field fluorescence microscope without amplification steps. The method offers single molecule detection sensitivity without using complex setups and thus volunteers as simple, robust, and reliable method for the sensitive detection of DNA and RNA sequences.

  20. Control of microparticles packing density in a microfluidic channel for bead based immunoassays applications

    NASA Astrophysics Data System (ADS)

    Caballero-Robledo, Gabriel; Guevara-Pantoja, Pablo

    2014-11-01

    Bead based immunoassays in microfluidic devices have shown to greatly outperform conventional methods. But if functional point-of-care devices are to be developed, precise and reproducible control over the granulate packings inside microchannels is needed. In this work we study the efficiency of a nanoparticles magnetic trap previously developed by B. Teste et al. [Lab Chip 11, 4207 (2011)] when we vary the compaction of micrometric iron beads packed against a restriction inside a microfluidic channel. The packing density of the beads is finely and reproducibly changed by applying a vibrational protocol originally developed for macroscopic, dry granular systems. We find, counterintuitively, that the most compact and stable packings are up to four times less efficient in trapping nano particles than the loosest packings. This work has been supported by Conacyt, Mexico, under Grant No. 180873.

  1. A bead-based western for high-throughput cellular signal transduction analyses

    PubMed Central

    Treindl, Fridolin; Ruprecht, Benjamin; Beiter, Yvonne; Schultz, Silke; Döttinger, Anette; Staebler, Annette; Joos, Thomas O.; Kling, Simon; Poetz, Oliver; Fehm, Tanja; Neubauer, Hans; Kuster, Bernhard; Templin, Markus F.

    2016-01-01

    Dissecting cellular signalling requires the analysis of large number of proteins. The DigiWest approach we describe here transfers the western blot to a bead-based microarray platform. By combining gel-based protein separation with immobilization on microspheres, hundreds of replicas of the initial blot are created, thus enabling the comprehensive analysis of limited material, such as cells collected by laser capture microdissection, and extending traditional western blotting to reach proteomic scales. The combination of molecular weight resolution, sensitivity and signal linearity on an automated platform enables the rapid quantification of hundreds of specific proteins and protein modifications in complex samples. This high-throughput western blot approach allowed us to identify and characterize alterations in cellular signal transduction that occur during the development of resistance to the kinase inhibitor Lapatinib, revealing major changes in the activation state of Ephrin-mediated signalling and a central role for p53-controlled processes. PMID:27659302

  2. Effect of enhanced pCO2 levels on the production of dissolved organic carbon and transparent exopolymer particles in short-term bioassay experiments

    NASA Astrophysics Data System (ADS)

    MacGilchrist, G. A.; Shi, T.; Tyrrell, T.; Richier, S.; Moore, C. M.; Dumousseaud, C.; Achterberg, E. P.

    2014-07-01

    It has been proposed that increasing levels of pCO2 in the surface ocean will lead to more partitioning of the organic carbon fixed by marine primary production into the dissolved rather than the particulate fraction. This process may result in enhanced accumulation of dissolved organic carbon (DOC) in the surface ocean and/or concurrent accumulation of transparent exopolymer particles (TEPs), with important implications for the functioning of the marine carbon cycle. We investigated this in shipboard bioassay experiments that considered the effect of four different pCO2 scenarios (ambient, 550, 750 and 1000 μatm) on unamended natural phytoplankton communities from a range of locations in the northwest European shelf seas. The environmental settings, in terms of nutrient availability, phytoplankton community structure and growth conditions, varied considerably between locations. We did not observe any strong or consistent effect of pCO2 on DOC production. There was a significant but highly variable effect of pCO2 on the production of TEPs. In three of the five experiments, variation of TEP production between pCO2 treatments was caused by the effect of pCO2 on phytoplankton growth rather than a direct effect on TEP production. In one of the five experiments, there was evidence of enhanced TEP production at high pCO2 (twice as much production over the 96 h incubation period in the 750 μatm treatment compared with the ambient treatment) independent of indirect effects, as hypothesised by previous studies. Our results suggest that the environmental setting of experiments (community structure, nutrient availability and occurrence of phytoplankton growth) is a key factor determining the TEP response to pCO2 perturbations.

  3. Effect of enhanced pCO2 levels on the production of DOC and TEP in short-term bioassay experiments

    NASA Astrophysics Data System (ADS)

    MacGilchrist, G. A.; Shi, T.; Tyrrell, T.; Richier, S.; Moore, C. M.; Dumousseaud, C.; Achterberg, E. P.

    2014-03-01

    It has been proposed that increasing levels of pCO2 in the surface ocean will lead to more partitioning of the organic carbon fixed by marine primary production into the dissolved rather than the particulate fraction. This process may result in enhanced accumulation of dissolved organic carbon (DOC) in the surface ocean and/or concurrent accumulation of transparent exopolymer particles (TEP), with important implications for the functioning of the marine carbon cycle. We investigated this in shipboard bioassay experiments that considered the effect of four different pCO2 scenarios (ambient, 550, 750 and 1000 μatm) on unamended natural phytoplankton communities from a range of locations in the northwest European shelf seas. The environmental settings, in terms of nutrient availability, phytoplankton community structure and growth conditions, varied considerably between locations. We did not observe any strong or consistent effect of pCO2 on DOC production. There was a significant but highly variable effect of pCO2 on the production of TEP. In three of the five experiments, variation of TEP production between pCO2 treatments was caused by the effect of pCO2 on phytoplankton growth rather than a direct effect on TEP production. In one of the five experiments, there was evidence of enhanced TEP production at high pCO2 (twice as much production over the 96 h incubation period in the 750 μatm treatment compared with the ambient treatment) independent of indirect effects, as hypothesised by previous studies. Our results suggest that the environmental setting of experiments (community structure, nutrient availability and occurrence of phytoplankton growth) is a key factor determining the TEP response to pCO2 perturbations.

  4. Viral RNA testing and automation on the bead-based CBNE detection microsystem.

    SciTech Connect

    Galambos, Paul C.; Bourdon, Christopher Jay; Farrell, Cara M.; Rossito, Paul; McClain, Jaime L.; Derzon, Mark Steven; Cullor, James Sterling; Rahimian, Kamayar

    2008-09-01

    We developed prototype chemistry for nucleic acid hybridization on our bead-based diagnostics platform and we established an automatable bead handling protocol capable of 50 part-per-billion (ppb) sensitivity. We are working towards a platform capable of parallel, rapid (10 minute), raw sample testing for orthogonal (in this case nucleic acid and immunoassays) identification of biological (and other) threats in a single sensor microsystem. In this LDRD we developed the nucleic acid chemistry required for nucleic acid hybridization. Our goal is to place a non-cell associated RNA virus (Bovine Viral Diarrhea, BVD) on the beads for raw sample testing. This key pre-requisite to showing orthogonality (nucleic acid measurements can be performed in parallel with immunoassay measurements). Orthogonal detection dramatically reduces false positives. We chose BVD because our collaborators (UC-Davis) can supply samples from persistently infected animals; and because proof-of-concept field testing can be performed with modification of the current technology platform at the UC Davis research station. Since BVD is a cattle-prone disease this research dovetails with earlier immunoassay work on Botulinum toxin simulant testing in raw milk samples. Demonstration of BVD RNA detection expands the repertoire of biological macromolecules that can be adapted to our bead-based detection. The resources of this late start LDRD were adequate to partially demonstrate the conjugation of the beads to the nucleic acids. It was never expected to be adequate for a full live virus test but to motivate that additional investment. In addition, we were able to reduce the LOD (Limit of Detection) for the botulinum toxin stimulant to 50 ppb from the earlier LOD of 1 ppm. A low LOD combined with orthogonal detection provides both low false negatives and low false positives. The logical follow-on steps to this LDRD research are to perform live virus identification as well as concurrent nucleic acid and

  5. Bead-Based Assays for Biodetection: From Flow-Cytometry to Microfluidics

    SciTech Connect

    Ozanich, Richard M.; Antolick, Kathryn C.; Bruckner-Lea, Cindy J.; Bunch, Kyle J.; Dockendorff, Brian P.; Grate, Jay W.; Nash, Michael A.; Tyler, Abby J.

    2009-05-04

    ABSTRACT The potential for the use of biological agents by terrorists is a real threat. Two approaches for detection of biological species will be described: 1) The use of microbead arrays for multiplexed flow cytometry detection of cytokines and botulinum neurotoxin simulant, and 2) a microfluidic platform for capture and separation of different size superparamagnetic nanoparticles followed by on-chip fluorescence detection of the sandwich complex. The methods and automated fluidic systems used for trapping functionalized microbeads will be described. This approach allows sample, assay reagents, and wash solutions to be perfused over a micro-column of beads, resulting in faster and more sensitive assays. The automated fluidic approach resulted in up to five-fold improvements in assay sensitivity/speed as compared to identical assays performed in a typical manual batch mode. A second approach for implementing multiplexed bead-based assays without using flow cytometry detection is currently under development. The goal of the microfluidic-based approach is to achieve rapid (<20 minutes), multiplexed (> 3 bioagents) detection using a simple and low-cost, integrated microfluidic/optical detection platform. Using fiber-optic guided laser-induced fluorescence, assay detection limits were shown to be in the 100’s of picomolar range (10’s of micrograms per liter) for botulinum neurotoxin simulant without any optimization of the microfluidic device or optical detection approach. Video taping magnetic nanoparticle capture and release was used to improve understanding of the process and revealed interesting behavior.

  6. Multiplexed bead-based mesofluidic system for detection of food-borne pathogenic bacteria.

    PubMed

    Jin, Sheng-Quan; Yin, Bin-Cheng; Ye, Bang-Ce

    2009-11-01

    In the present study, a simple and rapid multiplexed bead-based mesofluidic system (BMS) was developed for simultaneous detection of food-borne pathogenic bacteria, including Staphylococcus aureus, Vibrio parahaemolyticus, Listeria monocytogenes, Salmonella, Enterobacter sakazakii, Shigella, Escherichia coli O157:H7, and Campylobacter jejuni. This system is based on utilization of isothiocyanate-modified microbeads that are 250 mum in diameter, which were immobilized with specific amino-modified oligonucleotide probes and placed in polydimethylsiloxane microchannels. PCR products from the pathogens studied were pumped into microchannels to hybridize with the oligonucleotide-modified beads, and hybridization signals were detected using a conventional microarray scanner. The short sequences of nucleic acids (21 bases) and PCR products characteristic of bacterial pathogens could be detected at concentrations of 1 pM and 10 nM, respectively. The detection procedure could be performed in less than 30 min with high sensitivity and specificity. The assay was simple and fast, and the limits of quantification were in the range from 500 to 6,000 CFU/ml for the bacterial species studied. The feasibility of identification of food-borne bacteria was investigated with samples contaminated with bacteria, including milk, egg, and meat samples. The results demonstrated that the BMS method can be used for effective detection of multiple pathogens in different foodstuffs.

  7. Programmable and automated bead-based microfluidics for versatile DNA microarrays under isothermal conditions.

    PubMed

    Penchovsky, Robert

    2013-06-21

    Advances in modern genomic research depend heavily on applications of various devices for automated high- or ultra-throughput arrays. Micro- and nanofluidics offer possibilities for miniaturization and integration of many different arrays onto a single device. Therefore, such devices are becoming a platform of choice for developing analytical instruments for modern biotechnology. This paper presents an implementation of a bead-based microfluidic platform for fully automated and programmable DNA microarrays. The devices are designed to work under isothermal conditions as DNA immobilization and hybridization transfer are performed under steady temperature using reversible pH alterations of reaction solutions. This offers the possibility for integration of more selection modules onto a single chip compared to maintaining a temperature gradient. This novel technology allows integration of many modules on a single reusable chip reducing the application cost. The method takes advantage of demonstrated high-speed DNA hybridization kinetics and denaturation on beads under flow conditions, high-fidelity of DNA hybridization, and small sample volumes are needed. The microfluidic devices are applied for a single nucleotide polymorphism analysis and DNA sequencing by synthesis without the need for fluorescent removal step. Apart from that, the microfluidic platform presented is applicable to many areas of modern biotechnology, including biosensor devices, DNA hybridization microarrays, molecular computation, on-chip nucleic acid selection, high-throughput screening of chemical libraries for drug discovery.

  8. Bead-based assays for biodetection: from flow-cytometry to microfluidics

    NASA Astrophysics Data System (ADS)

    Ozanich, Richard M., Jr.; Antolick, Kathryn; Bruckner-Lea, Cynthia J.; Bunch, Kyle J.; Dockendorff, Brian P.; Grate, Jay W.; Nash, Michael A.; Tyler, Abby; Warner, Cynthia L.; Warner, Marvin G.

    2009-05-01

    The potential for the use of biological agents by terrorists is a real threat. Two approaches for antibody-based detection of biological species are described in this paper: 1) The use of microbead arrays for multiplexed flow cytometry detection of cytokines and botulinum neurotoxin simulant, and 2) a microfluidic platform for capture and separation of different size superparamagnetic nanoparticles followed by on-chip fluorescence detection of the sandwich complex. These approaches both involve the use of automated fluidic systems for trapping antibody-functionalized microbeads, which allows sample, assay reagents, and wash solutions to be perfused over a micro-column of beads, resulting in faster and more sensitive immunoassays. The automated fluidic approach resulted in up to five-fold improvements in immunoassay sensitivity/speed as compared to identical immunoassays performed in a typical manual batch mode. A second approach for implementing multiplexed bead-based immunoassays without using flow cytometry detection is currently under development. The goal of the microfluidic-based approach is to achieve rapid (<20 minutes), multiplexed (>= 3 bioagents) detection using a simple and low-cost, integrated microfluidic/optical detection platform. Using fiber-optic guided laser-induced fluorescence, assay detection limits were shown to be in the 100's of picomolar range (10's of micrograms per liter) for botulinum neurotoxin simulant without any optimization of the microfluidic device or optical detection approach.

  9. Optimization of multiplexed bead-based cytokine immunoassays for rat serum and brain tissue.

    PubMed

    Hulse, R E; Kunkler, P E; Fedynyshyn, J P; Kraig, R P

    2004-06-15

    The ability to simultaneously quantify multiple signaling molecule protein levels from microscopic neural tissue samples would be of great benefit to deciphering how they affect brain function. This follows from evidence that indicates signaling molecules can be pleiotropic and can have complex interactive behavior that is regionally and cellularly heterogeneous. Multiplexed examination of tissue proteins has been exceedingly difficult because of the absence of available techniques. This void now has been removed by the commercial availability of bead-based immunoassays for targeted proteins that allow analyses of up to 100 (6-150 kDa) proteins from as little as 12 microl. Thus far used only for sera (human and mouse) and culture media, we demonstrate here that sensitive (as low as 2 pg/ml), wide-ranging (up to 2-32 000 pg/ml), accurate (8% intra-assay covariance) and reliable (4-7% inter-assay covariance) measurements can be made of nine exemplary cytokines (e.g., IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-gamma, TNF-alpha) simultaneously not only from rat serum but, for the first time, also brain tissue. Furthermore, we describe animal handling procedures that minimize stress as determined by serum glucocorticoid levels since they can influence cytokine expression.

  10. A bead-based suspension array for the multiplexed detection of begomoviruses and their whitefly vectors.

    PubMed

    van Brunschot, S L; Bergervoet, J H W; Pagendam, D E; de Weerdt, M; Geering, A D W; Drenth, A; van der Vlugt, R A A

    2014-03-01

    Bead-based suspension array systems enable simultaneous fluorescence-based identification of multiple nucleic acid targets in a single reaction. This study describes the development of a novel approach to plant virus and vector diagnostics, a multiplexed 7-plex array that comprises a hierarchical set of assays for the simultaneous detection of begomoviruses and Bemisia tabaci, from both plant and whitefly samples. The multiplexed array incorporates genus, species and strain-specific assays, offering a unique approach for identifying both known and unknown viruses and B. tabaci species. When tested against a large panel of sequence-characterized begomovirus and whitefly samples, the array was shown to be 100% specific to the homologous target. Additionally, the multiplexed array was highly sensitive, efficiently and concurrently determining both virus and whitefly identity from single viruliferous whitefly samples. The detection limit for one assay within the multiplexed array that specifically detects Tomato yellow leaf curl virus-Israel (TYLCV-IL) was quantified as 200fg of TYLCV-IL DNA, directly equivalent to that of TYLCV-specific qPCR. Highly reproducible results were obtained over multiple tests. The flexible multiplexed array described in this study has great potential for use in plant quarantine, biosecurity and disease management programs worldwide.

  11. A bead-based proximity assay for BRD4 ligand discovery

    PubMed Central

    Roberts, Justin M.; Bradner, James E.

    2016-01-01

    Bromodomain-containing proteins have emerged as desirable targets for anti-neoplastic and anti-inflammatory drug discovery. Toward the development of selective inhibitors of the BET family of bromodomains, we optimized bead-based assays to detect interactions between bromodomains and poly-acetylated histone peptides. Donor and acceptor beads bound to target and ligand are brought into proximity by this protein-protein interaction. After laser illumination, singlet oxygen evolved from donor beads travels to the spatially close acceptor beads, resulting in chemiluminesence. This AlphaScreen assay has proven amendable to high-throughput screening, secondary validation, and specificity profiling during lead discovery and optimization. Here we report our protocol for assay development to measure inhibition of ligand binding to bromodomain containing protein 4 (BRD4). We discuss the discovery of an appropriate probe, optimization of bead, probe, and protein concentrations, and the derivation of protein-probe inhibition curves. Finally, we explore the implementation of this technology for high-throughput screening of potential BRD4 inhibitors. PMID:26629616

  12. Opportunities for bead-based multiplex assays in veterinary diagnostic laboratories.

    PubMed

    Christopher-Hennings, Jane; Araujo, Karla P C; Souza, Carlos J H; Fang, Ying; Lawson, Steven; Nelson, Eric A; Clement, Travis; Dunn, Michael; Lunney, Joan K

    2013-11-01

    Bead-based multiplex assays (BBMAs) are applicable for high throughput, simultaneous detection of multiple analytes in solution (from several to 50-500 analytes within a single, small sample volume). Currently, few assays are commercially available for veterinary applications, but they are available to identify and measure various cytokines, growth factors and their receptors, inflammatory proteins, kinases and inhibitors, neurobiology proteins, and pathogens and antibodies in human beings, nonhuman primates, and rodent species. In veterinary medicine, various nucleic acid and protein-coupled beads can be used in, or for the development of, antigen and antibody BBMAs, with the advantage that more data can be collected using approximately the same amount of labor as used for other antigen and antibody assays. Veterinary-related BBMAs could be used for detection of pathogens, genotyping, measurement of hormone levels, and in disease surveillance and vaccine assessment. It will be important to evaluate whether BBMAs are "fit for purpose," how costs and efficiencies compare between assays, which assays are published or commercially available for specific veterinary applications, and what procedures are involved in the development of the assays. It is expected that many veterinary-related BBMAs will be published and/or become commercially available in the next few years. The current review summarizes the BBMA technology and some of the currently available BBMAs developed for veterinary settings. Some of the human diagnostic BBMAs are also described, providing an example of possible templates for future development of new veterinary-related BBMAs.

  13. Bead-based microarray immunoassay for lung cancer biomarkers using quantum dots as labels.

    PubMed

    Liu, Lifen; Wu, Simin; Jing, Fengxiang; Zhou, Hongbo; Jia, Chunping; Li, Gang; Cong, Hui; Jin, Qinghui; Zhao, Jianlong

    2016-06-15

    In this study, we developed a multiplex immunoassay system that combines the suspension and planar microarray formats within a single layer of polydimethylsiloxane (PDMS) using soft lithography technology. The suspension format was based on the target proteins forming a sandwich structure between the magnetic beads and the quantum dot (QD) probes through specific antibody-antigen interactions. The planar microarray format was produced by fabricating an array of micro-wells in PDMS. Each micro-well was designed to trap a single microbead and eventually generated a microbead array within the PDMS chamber. The resultant bead-based on-chip assay could be used for simultaneously detecting three lung cancer biomarkers-carcinoembryonic antigen (CEA), fragments of cytokeratin 19 (CYFRA21-1) and neuron-specific enolase (NSE)-in 10 μl of human serum, with a wide linear dynamic range (1.03-111 ng/mL for CEA and CYFRA21-1; 9.26-1000 ng/ml for NSE) and a low detection limit (CEA: 0.19 ng/ml; CYFRA21-1: 0.97 ng/ml; NSE: 0.37 ng/ml; S/N=3). Our micro-well chip does not require complex e-beam lithography or the reactive ion etching process as with existing micro-well systems, which rely on expensive focused ion beam (FIB) milling or optical fiber bundles. Furthermore, the current approach is easy to operate without extra driving equipment such as pumps, and can make parallel detection for multiplexing with rapid binding kinetics, small reagent consumption and low cost. This work has demonstrated the importance of the successful application of on-chip multiplexing sandwich assays for the detection of biomarker proteins.

  14. A bead-based multiplex sandwich immunoassay to assess the abundance and posttranslational modification state of β-catenin.

    PubMed

    Groll, Nicola; Sommersdorf, Cornelia; Joos, Thomas O; Poetz, Oliver

    2015-01-01

    A system-wide analysis of cell signaling involves detecting and quantifying a range of proteins and their posttranslational modification states in the same cellular sample. We propose a protocol for a miniaturized, bead-based array and describe its efficiency in characterizing the different forms and functions of β-catenin. The protocol provides detailed instructions for cell culture and bead array assays that enable insights into complex networks at the systems level.

  15. AFOEHL Bioassay Services

    DTIC Science & Technology

    1990-12-01

    analysis, ANOVA, or non-parametric methods depending on the data collected. b. Claderoceran ( Ceriodaphnia dubia) Survival and Reproduction Test (Weber...different stimuli. BIOASSAY: An experimentally-based approach to determine if a living organism is impacted by some stimulus. CERIODAPHNIA : A very small... reproduction , activity, or any other measurable parameter. LC50 (Lethal Concentration, 50%): The concentration of a stimulus in water that will kill 50% of the

  16. Peptidomic analysis of Chinese shrimp ( Fenneropenaeus chinensis) hemolymph by magnetic bead-based MALDI-TOF MS

    NASA Astrophysics Data System (ADS)

    Wang, Baojie; Liu, Mei; Jiang, Keyong; Zhang, Guofan; Wang, Lei

    2013-03-01

    Peptides in shrimp hemolymph play an important role in the innate immune response. Analysis of hemolymph will help to detect and identify potential novel biomarkers of microbial infection. We used magnetic bead-based purification (ClinProt system) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) to characterize shrimp hemolymph peptides. Shrimp serum and plasma were used as the source of samples for comparative analysis, and it was found that serum was more suitable for shrimp hemolymph peptidomic analysis. To screen potential specific biomarkers in serum of immune-challenged shrimps, we applied magnetic bead-based MALDI-TOF MS to serum samples from 10 immune-challenged and 10 healthy shrimps. The spectra were analyzed using FlexAnalysis 3.0 and ClinProTools 2.1 software. Thirteen peptide peaks significantly different between the two groups were selected as candidate biomarkers of lipopolysaccharide (LPS)-infection. The diagnostic model established by genetic algorithm using five of these peaks was able to discriminate LPS-challenged shrimps from healthy control shrimps with a sensitivity of 90% and a specificity of 100%. Our approach in MALDITOF MS-based peptidomics is a powerful tool for screening bioactive peptides or biomarkers derived from hemolymph, and will help to enable a better understanding of the innate immune response of shrimps.

  17. Bioassay for assessing marine contamination

    SciTech Connect

    Lapota, D.; Copeland, H.; Mastny, G.; Rosenberger, D.; Duckworth, D.

    1996-03-01

    The Qwiklite bioassay, developed by the laboratory at NCCOSC, is used as a biological tool to gauge the extent of environmental contamination. Some species of marine phytoplankton produce bioluminescence. The Qwiklite bioassay determines acute response and chronic effects of a wide variety of toxicants upon bioluminescent dinotlagellates by measuring their light output after exposure.

  18. BIOASSAY VESSEL FAILURE ANALYSIS

    SciTech Connect

    Vormelker, P

    2008-09-22

    Two high-pressure bioassay vessels failed at the Savannah River Site during a microwave heating process for biosample testing. Improper installation of the thermal shield in the first failure caused the vessel to burst during microwave heating. The second vessel failure is attributed to overpressurization during a test run. Vessel failure appeared to initiate in the mold parting line, the thinnest cross-section of the octagonal vessel. No material flaws were found in the vessel that would impair its structural performance. Content weight should be minimized to reduce operating temperature and pressure. Outer vessel life is dependent on actual temperature exposure. Since thermal aging of the vessels can be detrimental to their performance, it was recommended that the vessels be used for a limited number of cycles to be determined by additional testing.

  19. A rapid immunomagnetic beads-based immunoassay for the detection of β-casein in bovine milk.

    PubMed

    Song, F; Zhou, Y; Li, Y S; Meng, X M; Meng, X Y; Liu, J Q; Lu, S Y; Ren, H L; Hu, P; Liu, Z S; Zhang, Y Y; Zhang, J H

    2014-09-01

    An immunomagnetic beads-based enzyme-linked immunosorbent assay (IMBs-ELISA) was developed for the detection of β-casein in bovine milk. Immunomagnetic beads (IMBs) were employed as the solid phase. The anti-β-casein monoclonal antibody (McAb) bound to IMBs was used as capture probe and an anti-β-casein polyclonal antibody (PcAb), labelled with horseradish peroxidase (HRP), was employed as detector probe. Three reaction and two washing steps were needed. Each reaction needed 10 min or less, which significantly shortened detection compared with classic sandwich ELISA. β-Casein in bovine milk was detected across a linear range (2-128 μg mL(-1)). Application results were in accordance with the Kjejdahl method, which suggests the IMBs-ELISA is rapid and reliable for the detection of β-casein in bovine milk.

  20. Development of a Multiplexed, Bead-Based Assessment Tool for Rapid Identification and Quantitation of Microorganisms in Field Samples. Final Report

    SciTech Connect

    Lowe, M.; Halden, R.

    2002-10-09

    This was the final report for DOE NABIR grant DE-FG02-01ER63264 (PI Mary Lowe). The grant was entitled ''Development of a Multiplexed Bead-Based Assessment Tool for Rapid Identification and Quantitation of Microorganisms in Field Samples.'' The grant duration was one year. The purpose was to develop a bead-based assay for measuring analyte DNAs in environmental PCR products and to apply the method to a field experiment. The primary experiment was located at the UMTRA Old Rifle site.

  1. Development of a novel bead-based 96-well filtration plate competitive immunoassay for the detection of Gentamycin.

    PubMed

    Ho, Tien Yu Jessica; Chan, Chia-Chung; Chan, KinGho; Wang, Yu Chieh; Lin, Jing-Tang; Chang, Cheng-Ming; Chen, Chien-Sheng

    2013-11-15

    We developed a sensitive, simple, inexpensive and rapid bead-based immunoassay platform, composed of liposomal nanovesicle amplification system, Gentamycin sulfate beads and 96-well filtration plates. In the beginning of the assay, Gentamycin sulfate beads, Gentamycin sulfate and Gentamycin specific antibody were incubated in a bottom-sealed 96-well filtration plate. After incubation, washing was done by running washing buffer through the unsealed filtration plate with only gravity and the antibody-Gentamycin bead complexes were retained in the plate. Fluorescent dye-loaded protein G-liposomal nanovesicles were then added to specifically bind to antibodies on the retained beads. After washing unbound nanovesicles, millions of fluorescent dye molecules were released by adding a detergent solution to lyse liposomal nanovesicles. The limit of detection (LOD) of this novel detection platform in TBS and in skim milk were 52.65 ng/mL and 14.16 ng/mL, which are both sufficient for detecting the 200 ng/mL Codex maximum residual level (MRL). The dynamic ranges were both from each of their LODs to 100 μg/mL. The 50% inhibition concentrations (IC50) in TBS and skim milk were 199.66 ng/mL and 360.81 ng/mL, respectively. We also demonstrated the good specificity of this platform by comparing detection results between pure Gentamycin solution and a mixture solution of 6 different antibiotics including Gentamycin in skim milk. The entire assay with 60 samples was conducted within 2h. In sum, this novel biosensing platform not only fulfilled most benefits of magnetic bead-based assays, but also was inexpensive and convenient by replacing the magnetic separation with filtration plate separation.

  2. Development of a bead-based multiplex PCR assay for the simultaneous detection of multiple Mycoplasma species.

    PubMed

    Righter, Daniel J; Rurangirwa, Fred R; Call, Douglas R; McElwain, Terry F

    2011-12-15

    We describe the development and analytical validation of a 7-plex polymerase chain reaction assay coupled to a bead-based liquid suspension array for detection of multiple ruminant Mycoplasma spp. The assay employs a combination of newly designed and previously validated primer-probe sets that target genetic loci specific for Mycoplasma bovis, Mycoplasma mycoides cluster, Mycoplasma mycoides subsp. mycoides SC (MmmSC) and Mycoplasma capricolum subspecies capripneumoniae (Mccp). Analytical sensitivity for the targeted Mycoplasma species ranged from 10 fg to 1 pg of purified gDNA extracted from broth cultures (approximately 8-800 MmmSC genome equivalents). In silico comparison of primers and probes, and analytical assessment with a range of near-neighbor Mycoplasma species and multiple bacterial respiratory pathogens demonstrated 100% analytical specificity of the assay. To assess assay performance and diagnostic specificity, 192 bovine respiratory samples were analyzed by incorporating a high throughput DNA extraction platform. The assay correctly classified all samples as negative for MmmSC or Mccp. All 33 field samples confirmed as positive for M. bovis by sequencing the uvrC gene were positive in the assay. The results from this study indicate that the bead-based liquid suspension array will provide a reliable, analytically sensitive and specific platform to simultaneously interrogate ruminant respiratory samples for multiple Mycoplasma species, including M. mycoides cluster organisms that are exotic to the United States. Sequential addition of primer-probe sets to the assay did not significantly impact analytical sensitivity of individual primer-probe combinations, suggesting that expanding the assay to include more Mycoplasma species will not compromise overall performance.

  3. EFFECT OF DIFFERENT REGIONS OF AMPLIFIED 16S RDNA ON A PERFORMANCE OF A MULTIPLEXED, BEAD-BASED METHOD FOR ANALYSIS OF DNA SEQUENCES IN ENVIRONMENTAL SAMPLES.

    EPA Science Inventory

    Using a bead-based method for multiplexed analysis of community DNA, the dynamics of aquatic microbial communities can be assessed. Capture probes, specific for a genus or species of bacteria, are attached to the surface of uniquely labeled, microscopic polystyrene beads. Primers...

  4. Dose-response curve of a microfluidic magnetic bead-based surface coverage sandwich assay.

    PubMed

    Cornaglia, Matteo; Trouillon, Raphaël; Tekin, H Cumhur; Lehnert, Thomas; Gijs, Martin A M

    2015-09-25

    Magnetic micro- and nanoparticles ('magnetic beads') have been used to advantage in many microfluidic devices for sensitive antigen (Ag) detection. Today, assays that use as read-out of the signal the number count of immobilized beads on a surface for quantification of a sample's analyte concentration have been among the most sensitive and have allowed protein detection lower than the fgmL(-1) concentration range. Recently, we have proposed in this category a magnetic bead surface coverage assay (Tekin et al., 2013 [1]), in which 'large' (2.8μm) antibody (Ab)-functionalized magnetic beads captured their Ag from a serum and these Ag-carrying beads were subsequently exposed to a surface pattern of fixed 'small' (1.0μm) Ab-coated magnetic beads. When the system was exposed to a magnetic induction field, the magnet dipole attractive interactions between the two bead types were used as a handle to approach both bead surfaces and assist with Ag-Ab immunocomplex formation, while unspecific binding (in absence of an Ag) of a large bead was reduced by exploiting viscous drag flow. The dose-response curve of this type of assay had two remarkable features: (i) its ability to detect an output signal (i.e. bead number count) for very low Ag concentrations, and (ii) an output signal of the assay that was non-linear with respect to Ag concentration. We explain here the observed dose-response curves and show that the type of interactions and the concept of our assay are in favour of detecting the lowest analyte concentrations (where typically either zero or one Ag is carried per large bead), while higher concentrations are less efficiently detected. We propose a random walk process for the Ag-carrying bead over the magnetic landscape of small beads and this model description explains the enhanced overall capture probability of this assay and its particular non-linear dose response curves.

  5. Facile Fabrication of a Silver Nanoparticle Immersed, Surface-Enhanced Raman Scattering Imposed Paper Platform through Successive Ionic Layer Absorption and Reaction for On-Site Bioassays.

    PubMed

    Kim, Wansun; Kim, Yeon-Hee; Park, Hun-Kuk; Choi, Samjin

    2015-12-23

    We introduce a novel, facile, rapid, low-cost, highly reproducible, and power-free synthesizable fabrication method of paper-based silver nanoparticle (AgNP) immersed surface-enhanced Raman scattering (SERS) platform, known as the successive ionic layer absorption and reaction (SILAR) method. The rough and porous properties of the paper led to direct synthesis of AgNPs on the surface as well as in the paper due to capillary effects, resulting in improved plasmon coupling with interparticles and interlayers. The proposed SERS platform showed an enhancement factor of 1.1 × 10(9), high reproducibility (relative standard deviation of 4.2%), and 10(-12) M rhodamine B highly sensitive detection limit by optimizing the SILAR conditions including the concentration of the reactive solution (20/20 mM/mM AgNO3/NaBH4) and the number of SILAR cycles (six). The applicability of the SERS platform was evaluated using two samples including human cervical fluid for clinical diagnosis of human papillomavirus (HPV) infection, associated with cervical cancer, and a malachite green (MG) solution for fungicide and parasiticide in aquaculture, associated with human carcinogenesis. The AgNP-immersed SERS-functionalized platform using the SILAR technique allowed for high chemical structure sensitivity without additional tagging or chemical modification, making it a good alternative for early clinical diagnosis of HPV infection and detection of MG-activated human carcinogenesis.

  6. Automated microfluidic platform of bead-based electrochemical immunosensor integrated with bioreactor for continual monitoring of cell secreted biomarkers.

    PubMed

    Riahi, Reza; Shaegh, Seyed Ali Mousavi; Ghaderi, Masoumeh; Zhang, Yu Shrike; Shin, Su Ryon; Aleman, Julio; Massa, Solange; Kim, Duckjin; Dokmeci, Mehmet Remzi; Khademhosseini, Ali

    2016-04-21

    There is an increasing interest in developing microfluidic bioreactors and organs-on-a-chip platforms combined with sensing capabilities for continual monitoring of cell-secreted biomarkers. Conventional approaches such as ELISA and mass spectroscopy cannot satisfy the needs of continual monitoring as they are labor-intensive and not easily integrable with low-volume bioreactors. This paper reports on the development of an automated microfluidic bead-based electrochemical immunosensor for in-line measurement of cell-secreted biomarkers. For the operation of the multi-use immunosensor, disposable magnetic microbeads were used to immobilize biomarker-recognition molecules. Microvalves were further integrated in the microfluidic immunosensor chip to achieve programmable operations of the immunoassay including bead loading and unloading, binding, washing, and electrochemical sensing. The platform allowed convenient integration of the immunosensor with liver-on-chips to carry out continual quantification of biomarkers secreted from hepatocytes. Transferrin and albumin productions were monitored during a 5-day hepatotoxicity assessment in which human primary hepatocytes cultured in the bioreactor were treated with acetaminophen. Taken together, our unique microfluidic immunosensor provides a new platform for in-line detection of biomarkers in low volumes and long-term in vitro assessments of cellular functions in microfluidic bioreactors and organs-on-chips.

  7. Automated microfluidic platform of bead-based electrochemical immunosensor integrated with bioreactor for continual monitoring of cell secreted biomarkers

    NASA Astrophysics Data System (ADS)

    Riahi, Reza; Shaegh, Seyed Ali Mousavi; Ghaderi, Masoumeh; Zhang, Yu Shrike; Shin, Su Ryon; Aleman, Julio; Massa, Solange; Kim, Duckjin; Dokmeci, Mehmet Remzi; Khademhosseini, Ali

    2016-04-01

    There is an increasing interest in developing microfluidic bioreactors and organs-on-a-chip platforms combined with sensing capabilities for continual monitoring of cell-secreted biomarkers. Conventional approaches such as ELISA and mass spectroscopy cannot satisfy the needs of continual monitoring as they are labor-intensive and not easily integrable with low-volume bioreactors. This paper reports on the development of an automated microfluidic bead-based electrochemical immunosensor for in-line measurement of cell-secreted biomarkers. For the operation of the multi-use immunosensor, disposable magnetic microbeads were used to immobilize biomarker-recognition molecules. Microvalves were further integrated in the microfluidic immunosensor chip to achieve programmable operations of the immunoassay including bead loading and unloading, binding, washing, and electrochemical sensing. The platform allowed convenient integration of the immunosensor with liver-on-chips to carry out continual quantification of biomarkers secreted from hepatocytes. Transferrin and albumin productions were monitored during a 5-day hepatotoxicity assessment in which human primary hepatocytes cultured in the bioreactor were treated with acetaminophen. Taken together, our unique microfluidic immunosensor provides a new platform for in-line detection of biomarkers in low volumes and long-term in vitro assessments of cellular functions in microfluidic bioreactors and organs-on-chips.

  8. Development of a Multiplexed Bead-Based Suspension Array for the Detection and Discrimination of Pospiviroid Plant Pathogens

    PubMed Central

    van Brunschot, Sharon L.; Bergervoet, Jan H. W.; Pagendam, Daniel E.; de Weerdt, Marjanne; Geering, Andrew D. W.; Drenth, André; van der Vlugt, René A. A.

    2014-01-01

    Efficient and reliable diagnostic tools for the routine indexing and certification of clean propagating material are essential for the management of pospiviroid diseases in horticultural crops. This study describes the development of a true multiplexed diagnostic method for the detection and identification of all nine currently recognized pospiviroid species in one assay using Luminex bead-based suspension array technology. In addition, a new data-driven, statistical method is presented for establishing thresholds for positivity for individual assays within multiplexed arrays. When applied to the multiplexed array data generated in this study, the new method was shown to have better control of false positives and false negative results than two other commonly used approaches for setting thresholds. The 11-plex Luminex MagPlex-TAG pospiviroid array described here has a unique hierarchical assay design, incorporating a near-universal assay in addition to nine species-specific assays, and a co-amplified plant internal control assay for quality assurance purposes. All assays of the multiplexed array were shown to be 100% specific, sensitive and reproducible. The multiplexed array described herein is robust, easy to use, displays unambiguous results and has strong potential for use in routine pospiviroid indexing to improve disease management strategies. PMID:24404188

  9. Validation of Flow Cytometry and Magnetic Bead-Based Methods to Enrich CNS Single Cell Suspensions for Quiescent Microglia.

    PubMed

    Volden, T A; Reyelts, C D; Hoke, T A; Arikkath, J; Bonasera, S J

    2015-12-01

    Microglia are resident mononuclear phagocytes within the CNS parenchyma that intimately interact with neurons and astrocytes to remodel synapses and extracellular matrix. We briefly review studies elucidating the molecular pathways that underlie microglial surveillance, activation, chemotaxis, and phagocytosis; we additionally place these studies in a clinical context. We describe and validate an inexpensive and simple approach to obtain enriched single cell suspensions of quiescent parenchymal and perivascular microglia from the mouse cerebellum and hypothalamus. Following preparation of regional CNS single cell suspensions, we remove myelin debris, and then perform two serial enrichment steps for cells expressing surface CD11b. Myelin depletion and CD11b enrichment are both accomplished using antigen-specific magnetic beads in an automated cell separation system. Flow cytometry of the resultant suspensions shows a significant enrichment for CD11b(+)/CD45(+) cells (perivascular microglia) and CD11b(+)/CD45(-) cells (parenchymal microglia) compared to starting suspensions. Of note, cells from these enriched suspensions minimally express Aif1 (aka Iba1), suggesting that the enrichment process does not evoke significant microglial activation. However, these cells readily respond to a functional challenge (LPS) with significant changes in the expression of molecules specifically associated with microglia. We conclude that methods employing a combination of magnetic-bead based sorting and flow cytometry produce suspensions highly enriched for microglia that are appropriate for a variety of molecular and cellular assays.

  10. Automated microfluidic platform of bead-based electrochemical immunosensor integrated with bioreactor for continual monitoring of cell secreted biomarkers

    PubMed Central

    Riahi, Reza; Shaegh, Seyed Ali Mousavi; Ghaderi, Masoumeh; Zhang, Yu Shrike; Shin, Su Ryon; Aleman, Julio; Massa, Solange; Kim, Duckjin; Dokmeci, Mehmet Remzi; Khademhosseini, Ali

    2016-01-01

    There is an increasing interest in developing microfluidic bioreactors and organs-on-a-chip platforms combined with sensing capabilities for continual monitoring of cell-secreted biomarkers. Conventional approaches such as ELISA and mass spectroscopy cannot satisfy the needs of continual monitoring as they are labor-intensive and not easily integrable with low-volume bioreactors. This paper reports on the development of an automated microfluidic bead-based electrochemical immunosensor for in-line measurement of cell-secreted biomarkers. For the operation of the multi-use immunosensor, disposable magnetic microbeads were used to immobilize biomarker-recognition molecules. Microvalves were further integrated in the microfluidic immunosensor chip to achieve programmable operations of the immunoassay including bead loading and unloading, binding, washing, and electrochemical sensing. The platform allowed convenient integration of the immunosensor with liver-on-chips to carry out continual quantification of biomarkers secreted from hepatocytes. Transferrin and albumin productions were monitored during a 5-day hepatotoxicity assessment in which human primary hepatocytes cultured in the bioreactor were treated with acetaminophen. Taken together, our unique microfluidic immunosensor provides a new platform for in-line detection of biomarkers in low volumes and long-term in vitro assessments of cellular functions in microfluidic bioreactors and organs-on-chips. PMID:27098564

  11. Quantification of mucosal mononuclear cells in tissues with a fluorescent bead-based polychromatic flow cytometry assay.

    PubMed

    Reeves, R Keith; Evans, Tristan I; Gillis, Jacqueline; Wong, Fay E; Connole, Michelle; Carville, Angela; Johnson, R Paul

    2011-03-31

    Since the vast majority of infections occur at mucosal surfaces, accurate characterization of mucosal immune cells is critically important for understanding transmission and control of infectious diseases. Standard flow cytometric analysis of cells obtained from mucosal tissues can provide valuable information on the phenotype of mucosal leukocytes and their relative abundance, but does not provide absolute cell counts of mucosal cell populations. We developed a bead-based flow cytometry assay to determine the absolute numbers of multiple mononuclear cell types in colorectal biopsies of rhesus macaques. Using 10-color flow cytometry panels and pan-fluorescent beads, cells were enumerated in biopsy specimens by adding a constant ratio of beads per mg of tissue and then calculating cell numbers/mg of tissue based on cell-to-bead ratios determined at the time of sample acquisition. Testing in duplicate specimens showed the assay to be highly reproducible (Spearman R=0.9476, P<0.0001). Using this assay, we report enumeration of total CD45(+) leukocytes, CD4(+) and CD8(+) T cells, B cells, NK cells, CD14(+) monocytes, and myeloid and plasmacytoid dendritic cells in colorectal biopsies, with cell numbers in normal rhesus macaques varying from medians of 4486 cells/mg (T cells) to 3 cells/mg (plasmacytoid dendritic cells). This assay represents a significant advancement in rapid, accurate quantification of mononuclear cell populations in mucosal tissues and could be applied to provide absolute counts of a variety of different cell populations in diverse tissues.

  12. Functional bioassays utilizing zooplankton: A comparison

    SciTech Connect

    McNaught, D.C.

    1989-01-01

    Functional zooplankton bioassays based on ingestion, reproduction and respiration are described, with methods for a new ingestion bioassay included. All bioassays are compared using three indices, including the variability of controls, the range of experimental responses, and a listing of contaminants causing inhibition/stimulation of response. The ingestion bioassay showed the greatest range of response, and was sensitive to pesticides, PCBs and heavy metals. It was also commonly characterized by a hormesis response. The reproduction bioassay showed the lowest variability, illustrated a reduced range of response, and was sensitive to nutrients and heavy metals. In one study, the respiration bioassay was sensitive only to PCBs.

  13. Sediment bioassays with oyster larvae

    SciTech Connect

    Chapman, P.M.; Morgan, J.D.

    1983-10-01

    Tests with naturally-occurring sediments are rare and sediment testing methodology is not standardized. The authors present a simple methodology for undertaking sediment bioassays with oyster larvae, and present data from a recent study to prove the utility of this method.

  14. An automated microfluidic system for single-stranded DNA preparation and magnetic bead-based microarray analysis

    PubMed Central

    Wang, Shuaiqin; Sun, Yujia; Liu, Yan; Xiang, Guangxin; Wang, Lei; Cheng, Jing; Liu, Peng

    2015-01-01

    We present an integrated microfluidic device capable of performing single-stranded DNA (ssDNA) preparation and magnetic bead-based microarray analysis with a white-light detection for detecting mutations that account for hereditary hearing loss. The entire operation process, which includes loading of streptavidin-coated magnetic beads (MBs) and biotin-labeled polymerase chain reaction products, active dispersion of the MBs with DNA for binding, alkaline denaturation of DNA, dynamic hybridization of the bead-labeled ssDNA to a tag array, and white-light detection, can all be automatically accomplished in a single chamber of the microchip, which was operated on a self-contained instrument with all the necessary components for thermal control, fluidic control, and detection. Two novel mixing valves with embedded polydimethylsiloxane membranes, which can alternately generate a 3-μl pulse flow at a peak rate of around 160 mm/s, were integrated into the chip for thoroughly dispersing magnetic beads in 2 min. The binding efficiency of biotinylated oligonucleotides to beads was measured to be 80.6% of that obtained in a tube with the conventional method. To critically test the performance of this automated microsystem, we employed a commercial microarray-based detection kit for detecting nine mutation loci that account for hereditary hearing loss. The limit of detection of the microsystem was determined as 2.5 ng of input K562 standard genomic DNA using this kit. In addition, four blood samples obtained from persons with mutations were all correctly typed by our system in less than 45 min per run. The fully automated, “amplicon-in-answer-out” operation, together with the white-light detection, makes our system an excellent platform for low-cost, rapid genotyping in clinical diagnosis. PMID:25825617

  15. DSSTOX NATIONAL TOXICOLOGY PROGRAM BIOASSAY ...

    EPA Pesticide Factsheets

    NTPBSI: National Toxicology Program Bioassay On-line Database Structure-Index Locator File. Database contains the results collected on approxiately 300 toxicity studies from shorter duration test and from genetic toxicity studies, both in vitro and in vivo tests. Database contains the results collected on approxiately 300 toxicity studies from shorter duration test and from genetic toxicity studies, both in vitro and in vivo tests.

  16. Soil bioassays as tools for sludge compost quality assessment

    SciTech Connect

    Domene, Xavier; Sola, Laura; Ramirez, Wilson; Alcaniz, Josep M.; Andres, Pilar

    2011-03-15

    Composting is a waste management technology that is becoming more widespread as a response to the increasing production of sewage sludge and the pressure for its reuse in soil. In this study, different bioassays (plant germination, earthworm survival, biomass and reproduction, and collembolan survival and reproduction) were assessed for their usefulness in the compost quality assessment. Compost samples, from two different composting plants, were taken along the composting process, which were characterized and submitted to bioassays (plant germination and collembolan and earthworm performance). Results from our study indicate that the noxious effects of some of the compost samples observed in bioassays are related to the low organic matter stability of composts and the enhanced release of decomposition endproducts, with the exception of earthworms, which are favored. Plant germination and collembolan reproduction inhibition was generally associated with uncomposted sludge, while earthworm total biomass and reproduction were enhanced by these materials. On the other hand, earthworm and collembolan survival were unaffected by the degree of composting of the wastes. However, this pattern was clear in one of the composting procedures assessed, but less in the other, where the release of decomposition endproducts was lower due to its higher stability, indicating the sensitivity and usefulness of bioassays for the quality assessment of composts.

  17. Plasmonically amplified fluorescence bioassay with microarray format

    NASA Astrophysics Data System (ADS)

    Gogalic, S.; Hageneder, S.; Ctortecka, C.; Bauch, M.; Khan, I.; Preininger, Claudia; Sauer, U.; Dostalek, J.

    2015-05-01

    Plasmonic amplification of fluorescence signal in bioassays with microarray detection format is reported. A crossed relief diffraction grating was designed to couple an excitation laser beam to surface plasmons at the wavelength overlapping with the absorption and emission bands of fluorophore Dy647 that was used as a label. The surface of periodically corrugated sensor chip was coated with surface plasmon-supporting gold layer and a thin SU8 polymer film carrying epoxy groups. These groups were employed for the covalent immobilization of capture antibodies at arrays of spots. The plasmonic amplification of fluorescence signal on the developed microarray chip was tested by using interleukin 8 sandwich immunoassay. The readout was performed ex situ after drying the chip by using a commercial scanner with high numerical aperture collecting lens. Obtained results reveal the enhancement of fluorescence signal by a factor of 5 when compared to a regular glass chip.

  18. Nanomaterial-Based Electrochemical Biosensors and Bioassays

    SciTech Connect

    Liu, Guodong; Mao, Xun; Gurung, Anant; Baloda, Meenu; Lin, Yuehe; He, Yuqing

    2010-08-31

    This book chapter summarizes the recent advance in nanomaterials for electrochemical biosensors and bioassays. Biofunctionalization of nanomaterials for biosensors fabrication and their biomedical applications are discussed.

  19. Bioassays Based on Molecular Nanomechanics

    DOE PAGES

    Majumdar, Arun

    2002-01-01

    Recent experiments have shown that when specific biomolecular interactions are confined to one surface of a microcantilever beam, changes in intermolecular nanomechanical forces provide sufficient differential torque to bend the cantilever beam. This has been used to detect single base pair mismatches during DNA hybridization, as well as prostate specific antigen (PSA) at concentrations and conditions that are clinically relevant for prostate cancer diagnosis. Since cantilever motion originates from free energy change induced by specific biomolecular binding, this technique is now offering a common platform for label-free quantitative analysis of protein-protein binding, DNA hybridization DNA-protein interactions, and in general receptor-ligandmore » interactions. Current work is focused on developing “universal microarrays” of microcantilever beams for high-throughput multiplexed bioassays.« less

  20. Assessment of space environmental factors by cytotoxicity bioassays

    NASA Astrophysics Data System (ADS)

    Hellweg, Christine E.; Arenz, Andrea; Baumstark-Khan, Christa

    2007-02-01

    Cellular bioassays for detection of cyto- and genotoxicity are useful in the risk assessment of space environmental factors. Such bioassay systems have the potential complement the physical detector systems used in space, insofar as they yield intrinsically biologically weighted measures of cellular responses. The experiment Cellular Responses to Radiation in Space (CERASP) has been selected by NASA/ESA to be performed on the International Space Station. It will supply basic information on the cellular response to radiation applied in microgravity. One of the biological endpoints under investigation will be survival reflected by radiation-dependent reduction of constitutive expression of the enhanced variant of green fluorescent protein (EGFP), originally isolated from the bioluminescent jellyfish Aequorea victoria. In this ground based study, the usefulness of this approach in comparison to standard techniques (colony forming ability test, MTT test) is shown.

  1. A bioaccumulation bioassay for freshwater sediments

    USGS Publications Warehouse

    Mac, Michael J.; Noguchi, George E.; Hesselberg, Robert J.; Edsall, Carol C.; Shoesmith, John A.; Bowker, James D.

    1990-01-01

    A laboratory bioassay is described for determining the bioavailability of contaminants from freshwater sediments. The bioassay consists of 10-d exposures to whole sediments under flow-through conditions. After testing five species, the fathead minnow (Pimephales promelas) and the earthworm (Lubricus terrestris) were recommended for use in the test. When the availability of polychlorinated biphenyls (PCBs), Hg and Zn from Great Lakes sediments was examined in laboratory exposures, only the PCBs were accumulated. A field validation study demonstrated that the magnitude of accumulation in laboratory exposures was similar to that in organisms caged in the field. A protocol is recommended for using the test as a standardized bioaccumulation bioassay.

  2. A flexible multiplex bead-based assay for detecting germline CDKN2A and CDK4 variants in melanoma-prone kindreds.

    PubMed

    Lang, Julie M; Shennan, Michael; Njauw, Jenny C-N; Luo, Su; Bishop, Julia N; Harland, Mark; Hayward, Nicholas K; Tucker, Margaret A; Goldstein, Alisa M; Landi, Maria T; Puig, Susana; Gruis, Nelleke A; Bergman, Wilma; Bianchi-Scarra, Giovanna; Ghiorzo, Paola; Hogg, David; Tsao, Hensin

    2011-02-01

    The presence of recurrent high-risk mutations in cyclin-dependent kinase inhibitor 2A/cyclin-dependent kinase 4 (CDKN2A/CDK4) among melanoma-prone families suggests that a high-throughput, multiplex assay could serve as an effective initial screening tool. To this end, we have developed a multiplex bead-based assay for high-throughput CDKN2A/CDK4 genotyping in the context of familial melanoma. Genomic DNA from 1,603 subjects (1,005 in training set and 598 in validation set) were amplified by multiplex PCR using five CDKN2A/CDK4 primer sets followed by multiplex allele-specific primer extension for 39 distinct germline variants. The products were then sorted and analyzed using the Luminex xMAP system. Genotypes were compared with previously determined sequence data. In the Toronto training cohort, all 145 samples with known variants were detected by the bead assay (100% concordance). Analysis of the 598 samples from the GenoMEL validation set led to identification of 150/155 expected variants (96.77%). Overall, the bead assay correctly genotyped 1,540/1,603 (96.07%) of all individuals in the study and 1,540/1,545 (99.68%) of individuals whose variants were represented in the probe set. Out of a total of 62,517 allelic calls, 62,512 (99.99%) were correctly assigned. The multiplex bead-based assay is an accurate method for genotyping CDKN2A/CDK4 variants and is potentially useful in genotyping low-to-moderate melanoma risk single-nucleotide polymorphisms.

  3. Two-generation saccharin bioassays.

    PubMed

    Arnold, D L

    1983-04-01

    The controversy regarding the safety of saccharin for human consumption started shortly after its discovery over 100 years ago and has yet to subside appreciably. The consumption of saccharin, particularly in North America, began to escalate when the U.S. Food and Drug Administration set new standards of identity which allowed foods containing artificial sweeteners to be promoted as "nonnutritive" or "noncaloric" sweeteners for use by the general public. In 1969, when cyclamates were banned, at least 10 single-generation feeding studies were undertaken with saccharin to more accurately assess the potential toxicological consequences resulting from the anticipated increase in its consumption. None of these studies resulted in any overt regulatory action. Subsequently, the introduction of the two-generation chronic toxicity/carcinogenicity bioassay added a new tool to the toxicologist's arsenal. Three two-generation studies using saccharin have since been conducted. The results from these studies clearly show that when rats were exposed to diets containing 5 or 7.5% sodium saccharin from the time of conception to death, an increased frequency of urinary bladder cancers was found, predominantly in the males. While some study results suggested that impurities in commercial saccharin or the presence of urinary tract calculi may have been responsible for the observed bladder tumors, it now appears that these possibilities are highly unlikely. The mechanism by which saccharin elicited the bladder tumors using the two-generation experiment has not been ascertained.

  4. 77 FR 14837 - Bioassay at Uranium Mills

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-13

    ... Development Branch, Division of Engineering, Office of Nuclear Regulatory Research. BILLING CODE 7590-01-P ... From the Federal Register Online via the Government Publishing Office ] NUCLEAR REGULATORY COMMISSION Bioassay at Uranium Mills AGENCY: Nuclear Regulatory Commission. ACTION: Draft regulatory...

  5. Bioassay criteria for environmental restoration workers

    SciTech Connect

    Carbaugh, E.H.; Bihl, D.E.

    1993-01-01

    Environmental restoration (ER) work at the U. S. Department of Energy Hanford Site posed questions concerning when to perform bioassay monitoring of workers for potential intakes of radioactivity. Application of criteria originally developed for use inside radionuclide processing facilities to ER work resulted in overly restrictive bioassay requirements. ER work typically involves site characterization or, excavating large quantities of potentially contaminated soil, rather than working with concentrated quantities of radioactivity as in a processing facility. An improved approach, tailored to ER work, provided soil contamination concentrations above which worker bioassay would be required. Soil concentrations were derived assuming acute or chronic intakes of 2% of an Annual Limit on Intake (ALI), or a potential committed effective dose equivalent of 100 mrem, and conservative dust loading of air from the work. When planning ER work, the anticipated soil concentration and corresponding need for bioassay could be estimated from work-site historical records. Once site work commenced, soil sampling and work-place surveys could be used to determine bioassay needs. This approach substantially reduced the required number of bioassay samples with corresponding reductions in analytical costs, schedules, and more flexible work-force management. (Work supported by the US Department of Energy under contract DOE-AC06-76RLO 1830.)

  6. A Colorimetric Bioassay for Perchlorate

    NASA Astrophysics Data System (ADS)

    Heinnickel, M. L.; Smith, S.; Coates, J. D.

    2007-12-01

    Recognition of perchlorate (ClO4-) as a widespread contaminant across the United States and its potential adverse affects towards human health has motivated the EPA to place ClO4- on its contaminant candidate list for drinking water supplies. While a federal MCL has not yet been set, a recommended public health goal of 1 ppb (μg.L-1) was established by the US EPA in 2002. To date, methods of detection require use of sensitive ion chromatographic equipment that are expensive, time consuming, and require highly trained personnel for use. Our studies are focused on the development of a highly sensitive, simple, and robust colorimetric bioassay based on the primary enzyme involved in microbial ClO4- reduction, the perchlorate reductase (Pcr). A previously published assay used reduced methyl viologen (MV, the dye is reduced with sodium hydrosulfite) as an electron donor to demonstrate Pcr activity. The assay directly correlates the amount of MV oxidized with the amount of ClO4- reduced by assuming a transfer of four electrons. To test this assumption, we compared actual concentrations of MV oxidized to ClO4- reduced in this assay. ClO4- concentrations were determined using a Dionex ICS-500 ion chromatography system, while MV concentrations were determined using a standard curve generated at 578 nm. Comparisons between the two revealed that twelve molecules of MV were oxidized for each molecule of ClO4- reduced. The oxidation of these additional eight MV molecules is explained by the interaction of the dye with chlorite (the product of the Pcr reaction) and other contaminants that could be present in the enzyme prep. This unsettling result indicated this assay would be problematic for the detection of ClO4- in soil, which has many chemicals that could react with MV. To improve upon this assay, we have tried to reduce ClO4- using less reactive dyes and reductants. The reductants ascorbic acid, NADH, and dithiothreitol drive Pcr catalyzed ClO4- reduction, however, they

  7. The Limits of Two-Year Bioassay Exposure Regimens for Identifying Chemical Carcinogens

    PubMed Central

    Huff, James; Jacobson, Michael F.; Davis, Devra Lee

    2008-01-01

    Background Chemical carcinogenesis bioassays in animals have long been recognized and accepted as valid predictors of potential cancer hazards to humans. Most rodent bioassays begin several weeks after birth and expose animals to chemicals or other substances, including workplace and environmental pollutants, for 2 years. New findings indicate the need to extend the timing and duration of exposures used in the rodent bioassay. Objectives In this Commentary, we propose that the sensitivity of chemical carcinogenesis bio-assays would be enhanced by exposing rodents beginning in utero and continuing for 30 months (130 weeks) or until their natural deaths at up to about 3 years. Discussion Studies of three chemicals of different structures and uses—aspartame, cadmium, and toluene—suggest that exposing experimental animals in utero and continuing exposure for 30 months or until their natural deaths increase the sensitivity of bioassays, avoid false-negative results, and strengthen the value and validity of results for regulatory agencies. Conclusions Government agencies, drug companies, and the chemical industry should conduct and compare the results of 2-year bioassays of known carcinogens or chemicals for which there is equivocal evidence of carcinogenicity with longer-term studies, with and without in utero exposure. If studies longer than 2 years and/or with in utero exposure are found to better identify potential human carcinogens, then regulatory agencies should promptly revise their testing guidelines, which were established in the 1960s and early 1970s. Changing the timing and dosing of the animal bioassay would enhance protection of workers and consumers who are exposed to potentially dangerous workplace or home contaminants, pollutants, drugs, food additives, and other chemicals throughout their lives. PMID:19057693

  8. Acarine attractants: Chemoreception, bioassay, chemistry and control.

    PubMed

    Carr, Ann L; Roe, Michael

    2016-07-01

    The Acari are of significant economic importance in crop production and human and animal health. Acaricides are essential for the control of these pests, but at the same time, the number of available pesticides is limited, especially for applications in animal production. The Acari consist of two major groups, the mites that demonstrate a wide variety of life strategies, i.e., herbivory, predation and ectoparasitism, and ticks which have evolved obligatory hematophagy. The major sites of chemoreception in the acarines are the chelicerae, palps and tarsi on the forelegs. A unifying name, the "foretarsal sensory organ" (FSO), is proposed for the first time in this review for the sensory site on the forelegs of all acarines. The FSO has multiple sensory functions including olfaction, gustation, and heat detection. Preliminary transcriptomic data in ticks suggest that chemoreception in the FSO is achieved by a different mechanism from insects. There are a variety of laboratory and field bioassay methods that have been developed for the identification and characterization of attractants but minimal techniques for electrophysiology studies. Over the past three to four decades, significant progress has been made in the chemistry and analysis of function for acarine attractants in mites and ticks. In mites, attractants include aggregation, immature female, female sex and alarm pheromones; in ticks, the attraction-aggregation-attachment, assembly and sex pheromones; in mites and ticks host kairomones and plant allomones; and in mites, fungal allomones. There are still large gaps in our knowledge of chemical communication in the acarines compared to insects, especially relative to acarine pheromones, and more so for mites than ticks. However, the use of lure-and-kill and lure-enhanced biocontrol strategies has been investigated for tick and mite control, respectively, with significant environmental advantages which warrant further study.

  9. Insights on novel particulate self-assembled drug delivery beads based on partial inclusion complexes between triglycerides and cyclodextrins.

    PubMed

    Aburahma, Mona Hassan

    2016-09-01

    Most of the newly designed drug molecules are lipophilic in nature and often encounter erratic absorption and low bioavailability after oral administration. Finding ways to enhance the absorption and bioavailability of these lipophilic drugs is one of the major challenges that face pharmaceutical industry nowadays. In view of that, the purpose of this review is to shed some light on a novel particulate self-assembling system named "beads" than can act as a safe carrier for delivering lipophilic drugs. The beads are prepared simply by mixing oils with cyclodextrin (CD) aqueous solution in mild conditions. A unique interaction between oil components and CD molecules occurs to form in situ surface-active complexes which are prerequisites for beads formation. This review mainly focuses on the fundamentals of beads preparation through reviewing present, yet scarce, literature. The key methods used for beads characterization are discussed in details. Also, the potential mechanisms by which beads increase the bioavailability of lipophilic drugs are illustrated. Finally, the related research areas that needs to be addressed in future for optimizing this promising delivery system are briefly outlined.

  10. Poultry litter toxicity comparison from various bioassays

    SciTech Connect

    Gupta, G.; Kelly, P. )

    1992-01-01

    Poultry litter contains many toxic chemicals including Cu, As, Pb, Cd, Hg, Se and PCBs. Poultry litter leachate has been shown to be more toxic to marine luminescent organisms (Photobacterium phosphoreum) than other farm animal manures. A comparison of toxicity of the poultry litter leachate was undertaken using various bioassays. The EC{sub 50} (or LC{sub 50}) value for the leachate with the Microtox and Daphnia bioassays was 2.9 g/L/ Nitrobacter and Pseudomonas bioassays were not useful in determining the leachate toxicity because of the nutritional properties of the litter. Poultry litter leachate was found to be mutagenic to strains TA 97, TA 98, TA 100 and TA 102 using the Ames Test.

  11. Sensitive detection and quantification of gliadin contamination in gluten-free food with immunomagnetic beads based liposomal fluorescence immunoassay.

    PubMed

    Chu, Pei-Tzu; Wen, Hsiao-Wei

    2013-07-17

    Gliadin from wheat is a common food allergen that can induce baker's asthma, wheat-dependent exercise-induced anaphylaxis, atopic dermatitis, and celiac disease. This gliadin assay focuses on rapidly screen and check for gluten contamination in raw materials and in the gluten-free food production process, not only for wheat-sensitive patients but also for the industries producing gluten-free foodstuffs. The developed assay incorporates the use of anti-gliadin antibody-conjugated immunomagnetic beads (IMBs) to capture the gliadin in samples and fluorescent dyes-loaded immunoliposomal nanovesicles (IMLNs) to produce and enhance the detection signal. Hence, a sandwich complex is formed as "IMBs-gliadin-IMLNs". Experimental results indicate that this detection platform exhibits good sensitivity for gliadin with a detection limit as low as 0.6 μg mL(-1) of gliadin; as the polyclonal antibody showed slight cross-reactions with barley and rye. Excellent recovery rates were found ranging from 83.5 to 102.6% as testing the spiked samples. Moreover, the CV (%) of intra- and inter-assay of this developed assay are 4.8-10.6% and 3.5-9.9%, respectively. Based on a parallel analysis of twenty food samples, the results of this developed assay provide a good consistency with those of an AOAC-approved ELISA kit without any false-negative results. The proposed assay method is thus a highly promising alternative method for detecting the contamination of gliadin in the food industry.

  12. Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

    NASA Astrophysics Data System (ADS)

    Kistrup, Kasper; Skotte Sørensen, Karen; Wolff, Anders; Fougt Hansen, Mikkel

    2015-04-01

    We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/μg and 1.72(14) nL/μg were found for Milli-Q water and lysis-binding buffer, respectively.

  13. Online magnetic bead based dynamic protein affinity selection coupled to LC-MS for the screening of acetylcholine binding protein ligands.

    PubMed

    Pochet, Lionel; Heus, Ferry; Jonker, Niels; Lingeman, Henk; Smit, August B; Niessen, Wilfried M A; Kool, Jeroen

    2011-06-15

    A magnetic beads based affinity-selection methodology towards the screening of acetylcholine binding protein (AChBP) binders in mixtures and pure compound libraries was developed. The methodology works as follows: after in solution incubation of His-tagged AChBP with potential ligands, and subsequent addition of cobalt (II)-coated paramagnetic beads, the formed bead-AChBP-ligand complexes are fetched out of solution by injection and trapping in LC tubing with an external adjustable magnet. Non binders are then washed to the waste followed by elution of ligands to a SPE cartridge by flushing with denaturing solution. Finally, SPE-LC-MS analysis is performed to identify the ligands. The advantage of the current methodology is the in solution incubation followed by immobilized AChBP ligand trapping and the capability of using the magnetic beads system as mobile/online transportable affinity SPE material. The system was optimized and then successfully demonstrated for the identification of AChBP ligands injected as pure compounds and for the fishing of ligands in mixtures. The results obtained with AChBP as target protein demonstrated reliable discrimination between binders with pK(i) values ranging from at least 6.26 to 8.46 and non-binders.

  14. RECOMMENDATIONS FOR UO3 PLANT BIOASSAY

    SciTech Connect

    Carbaugh, Eugene H.

    2010-07-12

    Alternative urine bioassay programs are described for application with decontamination and decommissioning activities at the Hanford UO3 Plant. The alternatives are based on quarterly or monthly urine bioassay for recycled uranium, assuming multiple acute inhalation intakes of recycled uranium occurring over a year. The inhalations are assumed to be 5µm AMAD particles of 80% absorption type F and 20% absorption type M. Screening levels, expressed as daily uranium mass excretion rates in urine, and the actions associated with these levels are provided for both quarterly and monthly sampling frequencies.

  15. In vitro bioassays of non-steroidal phytoestrogens.

    PubMed

    Markiewicz, L; Garey, J; Adlercreutz, H; Gurpide, E

    1993-05-01

    Some of the isoflavonoids present in human diet as well as in urine are expected to exert biologic effects as they have been reported to bind to estrogen receptors and to be estrogenic in other species. This report describes the in vitro assessment of estrogenic effects of isoflavonoids using human endometrial cells and tissue. The relative estrogenic potencies (EC50 values) of estradiol, 3 dietary isoflavonoids (coumestrol, genistein and daidzein) and one of their metabolites (equol), were estimated by using a recently developed multiwell plate in vitro bioassay based on the estrogen-specific enhancement of alkaline phosphatase (AlkP) activity in human endometrial adenocarcinoma cells of the Ishikawa-Var I line. The maximal AlkP activity elicited by the isoflavonoids tested was as high as that achieved with estradiol and their effects were suppressed by the antiestrogens 4-hydroxytamoxifen and ICI 164,384. These results indicate that estradiol and the isoflavonoids exert their effects on AlkP by similar interactions with the estrogen receptor, with potencies depending on binding affinities. The estrogenic effect of equol was confirmed by another in vitro bioassay, based on the estrogen-stimulated enhancement of prostaglandin F2 alpha output by fragments of human secretory endometrium.

  16. Bioassays on Illinois Waterway Dredged Material.

    DTIC Science & Technology

    1992-12-01

    48-hr) toxicity tests were conducted with two species, Pimephales promelas (the fathead minnow) and Daphnia magna (a freshwater cladoceran). A...chronic (21-day) toxicity test was also conducted using Daphnia magna . Animals were exposed separately to different concentrations of filtered and...unfiltered elutriates prepared from Acute, Cadmium, Daphnia magna , Pimephales promela, Ammonia, Chronic, Elutriate, Sediment, Bioassay, Cladoceran, Fathead

  17. Micro-organism distribution sampling for bioassays

    NASA Technical Reports Server (NTRS)

    Nelson, B. A.

    1975-01-01

    Purpose of sampling distribution is to characterize sample-to-sample variation so statistical tests may be applied, to estimate error due to sampling (confidence limits) and to evaluate observed differences between samples. Distribution could be used for bioassays taken in hospitals, breweries, food-processing plants, and pharmaceutical plants.

  18. Brine Shrimp Bioassays: A Useful Technique in Biological Investigations

    ERIC Educational Resources Information Center

    Rice, Stanley A.; Maness, Ian B.

    2004-01-01

    A technique to measure the potency of leaf compounds against herbivores with the use of a bioassay is described. Bioassays are useful in classes where students have career plans like medicine in which bioassays can be used as tools for screening plants for possible medicinal potency.

  19. Measuring immunoglobulin g antibodies to tetanus toxin, diphtheria toxin, and pertussis toxin with single-antigen enzyme-linked immunosorbent assays and a bead-based multiplex assay.

    PubMed

    Reder, Sabine; Riffelmann, Marion; Becker, Christian; Wirsing von König, Carl Heinz

    2008-05-01

    Bead-based assay systems offer the possibility of measuring several specific antibodies in one sample simultaneously. This study evaluated a vaccine panel of a multianalyte system that measures antibodies to tetanus toxin, diphtheria toxin, and pertussis toxin (PT) from Bordetella pertussis. The antibody concentrations of human immunoglobulin G (IgG) to PT, tetanus toxin, and diphtheria toxin were measured in 123 serum pairs (total of 246 sera) from a vaccine study. The multianalyte bead assay was compared to a standardized in-house IgG- anti-PT enzyme-linked immunosorbent assay (ELISA) of the German reference laboratory for bordetellae, as well as to various commercially available ELISAs for anti-PT IgG, anti-tetanus IgG, and anti-diphtheria IgG. The results of the multiplex assay regarding the antibodies against diphtheria toxin compared favorably with a regression coefficient of 0.938 for values obtained with an ELISA from the same manufacturer used as a reference. Similarly, antibodies to tetanus toxin showed a correlation of 0.910 between the reference ELISA and the multianalyte assay. A correlation coefficient of 0.905 was found when an "in-house" IgG anti-PT and the multiplex assay were compared. Compared to single ELISA systems from two other manufacturers, the multiplex assay performed similarly well or better. The multianalyte assay system was a robust system with fast and accurate results, analyzing three parameters simultaneously in one sample. The system was well suited to quantitatively determine relevant vaccine induced antibodies compared to in-house and commercially available single-antigen ELISA systems.

  20. Bayesian estimation of diagnostic accuracy of a new bead-based antibody detection test to reveal Toxoplasma gondii infections in pig populations.

    PubMed

    Bokken, Gertie C A M; Portengen, Lützen; Cornelissen, Jan B W J; Bergwerff, Aldert A; van Knapen, Frans

    2015-01-15

    The success of a Toxoplasma gondii surveillance program in European pig production systems depends partly on the quality of the test to detect infection in the population. The test accuracy of a recently developed serological bead-based assay (BBA) was investigated earlier using sera from experimentally infected animals. In this study, the accuracy of the BBA was determined by the use of sera from animals from two field subpopulations. As no T. gondii infection information of these animals was available, test accuracy was determined through a Bayesian approach allowing for conditional dependency between BBA and an ELISA test. The priors for prevalence were based on available information from literature, whereas for specificity vague non-informative priors were used. Priors for sensitivity were based either on available information or specified as non-informative. Posterior estimates for BBA sensitivity and specificity were (mode) 0.855 (Bayesian 95% credibility interval (bCI) 0.702-0.960) and 0.913 (bCI 0.893-0.931), respectively. Comparing the results of BBA and ELISA, sensitivity was higher for the BBA while specificity was higher for ELISA. Alternative priors for the sensitivity affected posterior estimates for sensitivity of both BBA and ELISA, but not for specificity. Because the difference in prevalence between the two subpopulations is small, and the number of infected animals is small as well, the precision of the posterior estimates for sensitivity may be less accurate in comparison to the estimates for specificity. The estimated value for specificity of BBA is at least optimally defined for testing pigs from conventional and organic Dutch farms.

  1. Bead-based immunoassay allows sub-picogram detection of histidine-rich protein 2 from Plasmodium falciparum and estimates reliability of malaria rapid diagnostic tests

    PubMed Central

    Rogier, Eric; Plucinski, Mateusz; Lucchi, Naomi; Mace, Kimberly; Chang, Michelle; Lemoine, Jean Frantz; Candrinho, Baltazar; Colborn, James; Dimbu, Rafael; Fortes, Filomeno; Udhayakumar, Venkatachalam; Barnwell, John

    2017-01-01

    Detection of histidine-rich protein 2 (HRP2) from the malaria parasite Plasmodium falciparum provides evidence for active or recent infection, and is utilized for both diagnostic and surveillance purposes, but current laboratory immunoassays for HRP2 are hindered by low sensitivities and high costs. Here we present a new HRP2 immunoassay based on antigen capture through a bead-based system capable of detecting HRP2 at sub-picogram levels. The assay is highly specific and cost-effective, allowing fast processing and screening of large numbers of samples. We utilized the assay to assess results of HRP2-based rapid diagnostic tests (RDTs) in different P. falciparum transmission settings, generating estimates for true performance in the field. Through this method of external validation, HRP2 RDTs were found to perform well in the high-endemic areas of Mozambique and Angola with 86.4% and 73.9% of persons with HRP2 in their blood testing positive by RDTs, respectively, and false-positive rates of 4.3% and 0.5%. However, in the low-endemic setting of Haiti, only 14.5% of persons found to be HRP2 positive by the bead assay were RDT positive. Additionally, 62.5% of Haitians showing a positive RDT test had no detectable HRP2 by the bead assay, likely indicating that these were false positive tests. In addition to RDT validation, HRP2 biomass was assessed for the populations in these different settings, and may provide an additional metric by which to estimate P. falciparum transmission intensity and measure the impact of interventions. PMID:28192523

  2. Rapid and sensitive detection of Escherichia coli O157:H7 in milk and ground beef using magnetic bead-based immunoassay coupled with tyramide signal amplification.

    PubMed

    Aydin, Muhsin; Herzig, Gene P D; Jeong, Kwang Cheol; Dunigan, Samantha; Shah, Parth; Ahn, Soohyoun

    2014-01-01

    Escherichia coli O157:H7 is a major foodborne pathogen that has posed serious problems for food safety and public health. Recent outbreaks and recalls associated with various foods contaminated by E. coli O157:H7 clearly indicate its deleterious effect on food safety. A rapid and sensitive detection assay is needed for this harmful organism to prevent foodborne illnesses and control outbreaks in a timely manner. We developed a magnetic bead-based immunoassay for detection of E. coli O157:H7 (the most well-known Shiga toxigenic E. coli strain) with a 96-well microplate as an assay platform. Immunomagnetic separation (IMS) and tyramide signal amplification were coupled to the assay to increase its sensitivity and specificity. This immunoassay was able to detect E. coli O157:H7 in pure culture with a detection limit of 50 CFU/ml in less than 3 h without an enrichment step. The detection limit was decreased 10-fold to 5 CFU/ml with addition of a 3-h enrichment step. When this assay was tested with other nontarget foodborne pathogens and common enteric bacteria, no cross-reactivity was found. When tested with artificially contaminated ground beef and milk samples, the assay sensitivity decreased two- to fivefold, with detection limits of 250 and 100 CFU/ml, respectively, probably because of the food matrix effect. The assay results also were compared with those of a sandwich-type enzyme-linked immunosorbent assay (ELISA) and an ELISA coupled with IMS; the developed assay was 25 times and 4 times more sensitive than the standard ELISA and the IMS-ELISA, respectively. Tyramide signal amplification combined with IMS can improve sensitivity and specificity for detection of E. coli O157:H7. The developed assay could be easily adapted for other foodborne pathogens and will contribute to improved food safety and public health.

  3. Semiconductor sensor embedded microfluidic chip for protein biomarker detection using a bead-based immunoassay combined with deoxyribonucleic acid strand labeling.

    PubMed

    Lin, Yen-Heng; Peng, Po-Yu

    2015-04-15

    Two major issues need to be addressed in applying semiconductor biosensors to detecting proteins in immunoassays. First, the length of the antibody on the sensor surface surpasses the Debye lengths (approximately 1 nm, in normal ionic strength solution), preventing certain specifically bound proteins from being tightly attached to the sensor surface. Therefore, these proteins do not contribute to the sensor's surface potential change. Second, these proteins carry a small charge and can be easily affected by the pH of the surrounding solution. This study proposes a magnetic bead-based immunoassay using a secondary antibody to label negatively charged DNA fragments for signal amplification. An externally imposed magnetic force attaches the analyte tightly to the sensor surface, thereby effectively solving the problem of the analyte protein's distance to the sensor surface surpassing the Debye lengths. In addition, a normal ion intensity buffer can be used without dilution for the proposed method. Experiments revealed that the sensitivity can be improved by using a longer DNA fragment for labeling and smaller magnetic beads as solid support for the antibody. By using a 90 base pair DNA label, the signal was 15 times greater than that without labeling. In addition, by using a 120 nm magnetic bead, a minimum detection limit of 12.5 ng mL(-1) apolipoprotein A1 can be measured. Furthermore, this study integrates a semiconductor sensor with a microfluidic chip. With the help of microvalves and micromixers in the chip, the length of the mixing step for each immunoassay has been reduced from 1h to 20 min, and the sample volume has been reduced from 80 μL to 10 μL. In practice, a protein biomarker in a urinary bladder cancer patient's urine was successfully measured using this technique. This study provides a convenient and effective method to measure protein using a semiconductor sensor.

  4. Bioassaying for ozone with pollen systems

    SciTech Connect

    Feder, W.A.

    1981-01-01

    Sensitivity to ozone of pollen germinating in vitro is closely correlated with ozone sensitivity of the pollen parent. Ozone-sensitive and tolerant pollen populations have been identified in tobacco, petunia, and tomato cultivars. The rate of tube elongation can be reversibly slowed or stopped by exposure to low concentrations of ozone. The performance of selected pollen populations can then be used to bioassay ozone in ambient air by introducing the air sample into a growth chamber where ozone-sensitive pollen in growing. Year-round pollen producion can be achieved in the greenhouse. Harvested pollen can be tested, packaged, and transported to user facilities without loss of vigor. Pollen populations are inexpensive to produce, respond reliably, and are simple to use as a bioassay for air quality.

  5. Environmental Quality Research Fish and Aufwuchs Bioassay

    DTIC Science & Technology

    1978-11-01

    components, hydrazine, 1, 1-dimethyl- hydrazine (UDMH), and l-methylhydrazine (MMH), to the three- spine stickleback (Gasterosteus acuteatus) and to aufwuchs...bioassays on the 3- spine stickleback (Gasterosteus aculeatus) and aufwuchs (attached periphyton growths). In some of these studies the Bay mussel (Mytilus...was assessed using the 3- spine stickleback (Gasterosteus aculeatus). This fish is native to Central San Francisco Bay and is a commonly used indicator

  6. Environmental Quality Research: Fish and Aufwuchs Bioassay

    DTIC Science & Technology

    1977-11-01

    toxicity of the rocket fuel, hydrazine, to the estuarine fish species, three- spine stickleback (Gasterosteus aculeatus) and aufwuchs. 2. Gas...The 96-hr LC 50 of hydrazine to three- spine sticklebacks was 3.4 mg/i (nominal initial concentration) using 24 hr solution renewal, but the estimated...lack of proper nutrients. A static bioassay of the effect of hydrazine on the 3- spine stickleback (Gasterosteus aculeatus) has been completed in the bay

  7. The great bioassay hoax, and alternatives

    SciTech Connect

    White, H.H.; Champ, M.A.

    1982-01-01

    A review of recent literature reveals large variations in results of bioassays, such as those proposed for solid waste testing. Sources of variation are categorized, and an estimate is made of the range in test results attributable to each source category. The age of the test organism is potentially the largest source of variation, and has effects up to five orders of magnitude on the outcome of bioassays. Other sources of variation have effects of several orders of magnitude, and nearly all sources have at least one-order-of-magnitude effect. It is concluded that bioassays cannot be used to predict the impact of contaminants introduced to an ecosystem or population, and therefore serve poorly as a tool in pollution management. Three criteria are proposed for judging the utility of any pollution evaluation technique. These are: the ability to incorporate good scientific practice in any application: the relationship of the measured response to the natural field response; and the relationship of the measured response to important ecosystem processes. Multi-species tests in micro- and mesocosms usually satisfy these criteria better than single-species tests, and may also be used to help develop simpler tests that satisfy these criteria. The focus of impact evaluation must be on growth, reproduction, and survival and parameters that can be related readily to them. Lastly, pollution management schemes have always recognized that human interests are the sole standard of which ecosystem effects are ''harmful,'' and which are not.

  8. Perspectives in avoidance-preference bioassays

    SciTech Connect

    Steele, C.W.; Taylor, D.H.; Strickler-Shaw, S.

    1996-12-31

    Although behavioral endpoints are used in hazard assessment, establishment of water quality criteria and assessment of a contaminant`s hazard to aquatic life rely primarily on standard acute and chronic toxicity tests. Sublethal effects of pollutants should, however, be of major concern because more organisms experience sublethal rather than acutely or chronically lethal exposures of contaminants. The avoidance-preference approach to behavioral bioassays is very useful in screening pollutants for which the mechanisms of perception or response are largely unknown. The underlying philosophy of these studies is that an animal which perceives a chemical can be attracted or repulsed by it. No response is frequently assumed to indicate lack of perception. All three responses have broad ecological implications. The authors discuss the conditions required for performing avoidance-preference bioassays, as well as their sensitivities, advantages, and limitations. In this regard, a comparative approach is used in examining the results of avoidance-preference bioassays with zebrafish in two different apparatuses. Finally, they compare the results of avoidance-preference studies with other measures of the behavioral toxicity of lead to tadpoles.

  9. A versatile electrowetting-based digital microfluidic platform for quantitative homogeneous and heterogeneous bio-assays

    NASA Astrophysics Data System (ADS)

    Vergauwe, Nicolas; Witters, Daan; Ceyssens, Frederik; Vermeir, Steven; Verbruggen, Bert; Puers, Robert; Lammertyn, Jeroen

    2011-05-01

    Electrowetting-on-dielectric (EWOD) lab-on-a-chip systems have already proven their potential within a broad range of bio-assays. Nevertheless, research on the analytical performance of those systems is limited, yet crucial for a further breakthrough in the diagnostic field. Therefore, this paper presents the intrinsic possibilities of an EWOD lab-on-a-chip as a versatile platform for homogeneous and heterogeneous bio-assays with high analytical performance. Both droplet dispensing and splitting cause variations in droplet size, thereby directly influencing the assay's performance. The extent to which they influence the performance is assessed by a theoretical sensitivity analysis, which allows the definition of a basic framework for the reduction of droplet size variability. Taking advantage of the optimized droplet manipulations, both homogeneous and heterogeneous bio-assays are implemented in the EWOD lab-on-a-chip to demonstrate the analytical capabilities and versatility of the device. A fully on-chip enzymatic assay is realized with high analytical performance. It demonstrates the promising capabilities of an EWOD lab-on-a-chip in food-related and medical applications, such as nutritional and blood analyses. Further, a magnetic bio-assay for IgE detection using superparamagnetic nanoparticles is presented whereby the nanoparticles are used as solid carriers during the bio-assay. Crucial elements are the precise manipulation of the superparamagnetic nanoparticles with respect to dispensing and separation. Although the principle of using nano-carriers is demonstrated for protein detection, it can be easily extended to a broader range of bio-related applications like DNA sensing. In heterogeneous bio-assays the chip surface is actively involved during the execution of the bio-assay. Through immobilization of specific biological compounds like DNA, proteins and cells a reactive chip surface is realized, which enhances the bio-assay performance. To demonstrate

  10. In-situ bioassays using caged bivalves

    SciTech Connect

    Salazar, M.H.; Salazar, S.M.

    1995-12-31

    It is important to make the distinction between chemical measurements to assess bioaccumulation potential versus biological measurements to assess potential bioeffects because bioaccumulation is not a bioeffect. Caging provides a unique opportunity to make synoptic measurements of each and facilitates making these measurements over space and time. Measuring bioaccumulation in resident and transplanted bivalves has probably been the most frequently used form of an in-situ bioassay because bivalves concentrate chemicals in their tissues. They are also easy to collect, cage, and measure. The authors have refined bivalve bioassay methods by minimizing the size range of test animals, making repetitive measurements of the same individuals, and standardizing test protocols for a variety of applications. They are now attempting to standardize criteria for accepting and interpreting data in the same way that laboratory bioassays have been standardized. Growth measurements can serve two purposes in this assessment strategy: (1) An integrated biological response endpoint that is easily quantifiable and with significance to the population, and (2) A means of calibrating bioaccumulation by assessing the relative health and physiological state of tissues that have accumulated the chemicals. In general, the authors have found the highest bioconcentration factors associated with the highest growth rates, the highest concentrations ({micro}g/g) of chemicals in juvenile mussels, and the highest chemical content ({micro}g/animal) in adult mussels. Without accounting for possible dilution of chemical concentrations by tissue growth or magnification through degrowth, contaminant concentrations can be misleading. Examples are provided for the Sudbury River in Massachusetts (Elliptio complanata), San Diego Bay (Mytilus galloprovincialis), and the Harbor Island Superfund Site in Puget Sound (Mytilus trossulus).

  11. A Multichannel Bioluminescence Determination Platform for Bioassays.

    PubMed

    Kim, Sung-Bae; Naganawa, Ryuichi

    2016-01-01

    The present protocol introduces a multichannel bioluminescence determination platform allowing a high sample throughput determination of weak bioluminescence with reduced standard deviations. The platform is designed to carry a multichannel conveyer, an optical filter, and a mirror cap. The platform enables us to near-simultaneously determine ligands in multiple samples without the replacement of the sample tubes. Furthermore, the optical filters beneath the multichannel conveyer are designed to easily discriminate colors during assays. This optical system provides excellent time- and labor-efficiency to users during bioassays.

  12. Aspartame bioassay findings portend human cancer hazards.

    PubMed

    Huff, James; LaDou, Joseph

    2007-01-01

    The U.S. Food and Drug Administration (FDA) should reevaluate its position on aspartame as being safe under all conditions. Animal bioassay results predict human cancer risks, and a recent animal study confirms that there is a potential aspartame risk to humans. Aspartame is produced and packaged in China for domestic use and global distribution. Japan, France, and the United States are also major producers. No study of long-term adverse occupational health effects on aspartame workers have been conducted. The FDA should consider sponsoring a prospective epidemiologic study of aspartame workers.

  13. Sediment acute toxicity testing utilizing short-term bioassays

    SciTech Connect

    Campbell, M.G.

    1991-01-01

    The purpose of this study was to investigate the usefulness of two new bioassays for acute toxicity assessments of sediments. A bacterial bioassay based on inhibition of alpha-glucosidase biosynthesis in Bacillus licheniformis and a 48-hour lethality bioassay employing the benthic cladoceran, Chydorus sphaericus. were evaluated by direct comparisons with standard bioassays, using sediment samples collected from various sites in Florida. This study showed that the bioassay based on inhibition of alpha-glucosidase biosynthesis in Bacillus licheniformis was useful in the acute toxicity screening of sediment elutriates. In regards to Escambia County, Florida samples, the assay was comparable with the Microtox assay and was especially sensitive for samples containing metals. To determine an appropriate procedure for assessing hydrophobic contaminants of sediments in the B. licheniformis bioassay, two extracting procedures were compared. Based on the responses in the Microtox bioassay, shaking sediment samples in methylene chloride produced extracts that were significantly higher in toxicity than extracts obtained by sonication for eight of the ten sediment samples tested. Comparisons of methanol and dimethyl sulfoxide (DMSO) as exchange solvents revealed that there was generally no significant difference between these solvents in terms of toxicity in the Microtox assay. Solvent extracts prepared by shaking and exchanged into methanol showed lower toxicity in the B. licheniformis bioassay than in the Microtox assay. Observed sediment toxicity in both bioassays was expressed in terms of the equivalent dry weight concentration of sediment causing 50% inhibition of the assay organism.

  14. Characterization of currently marketed heparin products: adverse event relevant bioassays.

    PubMed

    Sommers, Cynthia D; Montpas, Nicolas; Adam, Albert; Keire, David A

    2012-01-01

    The polyanion oversulfated chondroitin sulfate (OSCS) was identified as a contaminant in heparin products and was associated with severe hypotensive responses and other symptoms in patients receiving the drug. The OSCS associated adverse reactions were attributed to activation of the contact system via the plasma mediator, activated factor XII (FXIIa), which triggers kallikrein (KK) activity. Unlike heparin alone, OSCS, is able to activate FXII in plasma and stably bind to FXIIa enhancing plasma KK activity and the induction of vasoactive mediators such as bradykinin (BK), C3a and C5a. Similarly OSCS can interfere with heparin neutralization by the polycationic drug protamine. Here, we assess heparin (heparin sodium, dalteparin, tinzaparin or enoxaparin)-protamine complex formation and plasma based bioassays of KK, BK and C5a in a 96-well plate format. We establish the normal range of variation in the optimized bioassays across multiple lots from 9 manufacturers. In addition, because other oversulfated (OS) glycosaminoglycans (GAGs) besides OSCS could also serve as possible economically motivated adulterants (EMAs) to heparin, we characterize OS-dermatan sulfate (OSDS), OS-heparan sulfate (OSHS) and their native forms in the same assays. For the protamine test, OS-GAGs could be distinguished from heparin. For the KK assay, OSCS and OSDS were most potent followed by OSHS, and all had similar efficacies. Finally, OSDS had a greater efficacy in the C5a and BK assays followed by OSCS then OSHS. These data established the normal range of response of heparin products in these assays and the alteration in the responses in the presence of possible EMAs.

  15. Bioassaying for ozone with pollen systems.

    PubMed Central

    Feder, W A

    1981-01-01

    Sensitivity to ozone of pollen germinating in vitro is closely correlated with ozone sensitivity of the pollen parent. Ozone-sensitive and tolerant pollen populations have been identified in tobacco, petunia, and tomato cultivars. The rate of tube elongation can be reversibly slowed or stopped by exposure to low concentrations of ozone. Tube growth rates in the presence of a range of ozone dosages, of pollen populations exhibiting differing ozone sensitivity can be measured and different growth rates can be correlated with ozone dosages. The performance of selected pollen populations can then be used to bioassay ozone in ambient air by introducing the air sample into a growth chamber where ozone-sensitive pollen in growing. Petunia and tobacco pollen are especially useful because they store well at ordinary freezer temperatures and do not require special preparation prior to storage. Modified Brewbacker's growth medium is suitable for growth of both these pollen types. Four useful cultivars are Bel W-3, ozone-sensitive and Bel B, ozone-tolerant tobacco, and White Bountiful, ozone-sensitive and Blue Lagoon, ozone-tolerant petunia. Observations can be made directly by using a TV scanner, or by time lapse or interval photography. Year-round pollen production can be achieved in the greenhouse. Harvested pollen can be tested, packaged, and transported to user facilities without loss of vigor. Pollen populations are inexpensive to produce, respond reliably, and are simple to use as a bioassay for air quality. Images FIGURE 2. FIGURE 3. FIGURE 4. PMID:7460876

  16. Urine sample collection protocols for bioassay samples

    SciTech Connect

    MacLellan, J.A.; McFadden, K.M.

    1992-11-01

    In vitro radiobioassay analyses are used to measure the amount of radioactive material excreted by personnel exposed to the potential intake of radioactive material. The analytical results are then used with various metabolic models to estimate the amount of radioactive material in the subject`s body and the original intake of radioactive material. Proper application of these metabolic models requires knowledge of the excretion period. It is normal practice to design the bioassay program based on a 24-hour excretion sample. The Hanford bioassay program simulates a total 24-hour urine excretion sample with urine collection periods lasting from one-half hour before retiring to one-half hour after rising on two consecutive days. Urine passed during the specified periods is collected in three 1-L bottles. Because the daily excretion volume given in Publication 23 of the International Commission on Radiological Protection (ICRP 1975, p. 354) for Reference Man is 1.4 L, it was proposed to use only two 1-L bottles as a cost-saving measure. This raised the broader question of what should be the design capacity of a 24-hour urine sample kit.

  17. Urine sample collection protocols for bioassay samples

    SciTech Connect

    MacLellan, J.A.; McFadden, K.M.

    1992-11-01

    In vitro radiobioassay analyses are used to measure the amount of radioactive material excreted by personnel exposed to the potential intake of radioactive material. The analytical results are then used with various metabolic models to estimate the amount of radioactive material in the subject's body and the original intake of radioactive material. Proper application of these metabolic models requires knowledge of the excretion period. It is normal practice to design the bioassay program based on a 24-hour excretion sample. The Hanford bioassay program simulates a total 24-hour urine excretion sample with urine collection periods lasting from one-half hour before retiring to one-half hour after rising on two consecutive days. Urine passed during the specified periods is collected in three 1-L bottles. Because the daily excretion volume given in Publication 23 of the International Commission on Radiological Protection (ICRP 1975, p. 354) for Reference Man is 1.4 L, it was proposed to use only two 1-L bottles as a cost-saving measure. This raised the broader question of what should be the design capacity of a 24-hour urine sample kit.

  18. Signal Amplification of Bioassay Using Zinc Nanomaterials

    NASA Astrophysics Data System (ADS)

    Cowles, Chad L.

    An emerging trend in the analytical detection sciences is the employment of nanomaterials for bioassay signal transduction to identify analytes critical to public health. These nanomaterials have been specifically investigated for applications which require identification of trace levels of cells, proteins, or other molecules that can have broad ranging impacts to human health in fields such as clinical diagnostics, environmental monitoring, food and drink control, and the prevention of bioterrorism. Oftentimes these nanoparticle-based signal transduction or amplification approaches offer distinct advantages over conventional methods such as increased sensitivity, rapidity, or stability. The biological application of nanoparticles however, does suffer from drawbacks that have limited more widespread adoption of these techniques. Some of these drawbacks are, high cost and toxicity, arduous synthesis methods, functionalization and bioconjugation challenges, and laboratory disposal and environmental hazard issues, all of which have impeded the progression of this technology in some way or another. This work aims at developing novel techniques that offer solutions to a number of these hurdles through the development of new nanoparticle-based signal transduction approaches and the description of a previously undescribed nanomaterial. Zinc-based nanomaterials offer the opportunity to overcome some of the limitations that are encountered when other nanomaterials are employed for bioassay signal transduction. On the other hand, the biological application of zinc nanomaterials has been difficult because in general their fluorescence is in the blue range and the reported quantum yields are usually too low for highly sensitive applications. The advantages of using zinc nanomaterials for biological applications, such as reduced toxicity, simple synthesis, low cost, and straightforward functionalization strategies contribute to the research interest in their application as

  19. A bioassay for the measurement of insecticide concentration.

    PubMed

    Grant, R J

    2001-10-01

    A bioassay was developed to measure insecticide residues using fruit flies (Drosophila melongaster). After adding a known volume of sampling solution, the time at which 50% of the flies were dead (LT(50)) was recorded and cross-referenced to the appropriate calibration curve. Using known standards, comparable results were obtained using the bioassay and GC-MS. The bioassay allows concentrations of synthetic pyrethroids as low as 1 pg L(-1) to be measured with a variance of < 5%. The bioassay can be used reliably over a wide range of temperatures and it is tolerant to a range of pH and surface tensions of the test solution. The whole bioassay is compact, physically robust, and simple to use; hence, it could be of use in the field as a quick preliminary assessment of water contamination.

  20. Cell-based bioassays in microfluidic systems

    NASA Astrophysics Data System (ADS)

    Itle, Laura J.; Zguris, Jeanna C.; Pishko, Michael V.

    2004-12-01

    The development of cell-based bioassays for high throughput drug screening or the sensing of biotoxins is contingent on the development of whole cell sensors for specific changes in intracellular conditions and the integration of those systems into sample delivery devices. Here we show the feasibility of using a 5-(and-6)-carboxy SNARF-1, acetoxymethyl ester, acetate, a fluorescent dye capable of responding to changes in intracellular pH, as a detection method for the bacterial endotoxin, lipopolysaccharide. We used photolithography to entrap cells with this dye within poly(ethylene) glyocol diacrylate hydrogels in microfluidic channels. After 18 hours of exposure to lipopolysaccharide, we were able to see visible changes in the fluorescent pattern. This work shows the feasibility of using whole cell based biosensors within microfluidic networks to detect cellular changes in response to exogenous agents.

  1. Circular Bioassay Platforms for Applications in Microwave-Accelerated Techniques

    PubMed Central

    Mohammed, Muzaffer; Clement, Travis C.; Aslan, Kadir

    2014-01-01

    In this paper, we present the design of four different circular bioassay platforms, which are suitable for homogeneous microwave heating, using theoretical calculations (i.e., COMSOL™ multiphysics software). Circular bioassay platforms are constructed from poly(methyl methacrylate) (PMMA) for optical transparency between 400–800 nm, has multiple sample capacity (12, 16, 19 and 21 wells) and modified with silver nanoparticle films (SNFs) to be used in microwave-accelerated bioassays (MABs). In addition, a small monomode microwave cavity, which can be operated with an external microwave generator (100 W), for use with the bioassay platforms in MABs is also developed. Our design parameters for the circular bioassay platforms and monomode microwave cavity during microwave heating were: (i) temperature profiles, (ii) electric field distributions, (iii) location of the circular bioassay platforms inside the microwave cavity, and (iv) design and number of wells on the circular bioassay platforms. We have also carried out additional simulations to assess the use of circular bioassay platforms in a conventional kitchen microwave oven (e.g., 900 W). Our results show that the location of the circular bioassay platforms in the microwave cavity was predicted to have a significant effect on the homogeneous heating of these platforms. The 21-well circular bioassay platform design in our monomode microwave cavity was predicted to offer a homogeneous heating pattern, where inter-well temperature was observed to be in between 23.72–24.13°C and intra-well temperature difference was less than 0.21°C for 60 seconds of microwave heating, which was also verified experimentally. PMID:25568813

  2. Circular Bioassay Platforms for Applications in Microwave-Accelerated Techniques.

    PubMed

    Mohammed, Muzaffer; Clement, Travis C; Aslan, Kadir

    2014-12-02

    In this paper, we present the design of four different circular bioassay platforms, which are suitable for homogeneous microwave heating, using theoretical calculations (i.e., COMSOL™ multiphysics software). Circular bioassay platforms are constructed from poly(methyl methacrylate) (PMMA) for optical transparency between 400-800 nm, has multiple sample capacity (12, 16, 19 and 21 wells) and modified with silver nanoparticle films (SNFs) to be used in microwave-accelerated bioassays (MABs). In addition, a small monomode microwave cavity, which can be operated with an external microwave generator (100 W), for use with the bioassay platforms in MABs is also developed. Our design parameters for the circular bioassay platforms and monomode microwave cavity during microwave heating were: (i) temperature profiles, (ii) electric field distributions, (iii) location of the circular bioassay platforms inside the microwave cavity, and (iv) design and number of wells on the circular bioassay platforms. We have also carried out additional simulations to assess the use of circular bioassay platforms in a conventional kitchen microwave oven (e.g., 900 W). Our results show that the location of the circular bioassay platforms in the microwave cavity was predicted to have a significant effect on the homogeneous heating of these platforms. The 21-well circular bioassay platform design in our monomode microwave cavity was predicted to offer a homogeneous heating pattern, where inter-well temperature was observed to be in between 23.72-24.13°C and intra-well temperature difference was less than 0.21°C for 60 seconds of microwave heating, which was also verified experimentally.

  3. Assessing the potential risk of oil-field produced waters using a battery of bioassays/biomarkers.

    PubMed

    Li, Jian; Ma, Mei; Cui, Qing; Wang, Zijian

    2008-06-01

    A battery of in vitro bioassays was conducted to assess the potential risks of organic extracts from oilfield produced wastewaters and from the receiving waters. In SOS/umu bioassay for the genotoxicity, our results showed that direct and indirect genotoxic substances were observed and metabolic activation greatly enhanced the genotoxic effects. In Ethoxyresorufin-O-deethylase bioassay, levels of AhR-agonists, expressed as 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalences, varied from 13.3 to 16.7 pg L(-1). We conclude that oilfield produced wastewater contains substantial quantity of indirect genotoxic substances exclusive of AhR agonists. Both genotoxic and AhR agonistic chemicals could not be effectively removed by the treatment processes.

  4. Genotoxicity of SPL (spent pot lining) as measured by Tradescantia bioassays.

    PubMed

    Andrade-Vieira, L F; Davide, L C; Gedraite, L S; Campos, J M S; Azevedo, H

    2011-10-01

    Spent Pot Liner (SPL) is a solid waste product generated in the process of aluminum production. Tradescantia micronuclei (Trad-MN) and stamen hair mutation (Trad-SHM) bioassays are very useful tests to assess genotoxicity of environmental pollutants. In the present study, we intended to investigate the genotoxicity of this waste with Tradescantia bioassays using leachates of SPL simulating the natural leachability of SPL in soil. The formation of micronuclei (MN) was found to be concentration dependent. MN frequency enhanced significantly with SPL treatment. In addition, SPL also appeared to increase the percentage of dyads and triads. Trad-SHM assay showed that SPL increases pink mutation events as SPL concentration increases. These results demonstrated that SPL is a cytogenotoxic agent that affects different genetic end-points (induction of micronuclei and point mutations) even at low concentration (2% and 3%).

  5. Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays.

    SciTech Connect

    Anstey, Mitchell R.; Fruetel, Julia A.; Foster, Michael E.; Hayden, Carl C.; Buckley, Heather L.; Arnold, John

    2013-09-01

    Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves "Click" chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

  6. A bioassay to estimate root penetration by nematodes.

    PubMed

    Kaplan, D T; Davis, E L

    1991-10-01

    An in vitro bioassay with a 96-well microtiter plate was used to study the effect of lectins on burrowing nematode penetration of citrus roots. In each well, one 4-mm root segment, excised from the zone of elongation of rough lemon roots, was buried in 0.88 g dry sand. Addition of a Radopholus citrophilus suspension containing ca. 300 nematodes in 50 mu1 test solution completely moistened the sand in each well. The technique assured uniform treatment concentration throughout the medium. Within 16-24 hours, burrowing nematodes penetrated citrus root pieces, primarily through the cut ends. The lectins (100 mug/ml) Concanavalin A (Con A), soybean agglutinin (SBA), wheat germ agglutinin (WGA), and Lotus tetragonolobus agglutinin (LOT) stimulated an increase in penetration of citrus root segments by Radopholus citrophilus. Concentrations as low as 12.5 mug/ml Con A, LOT, and WGA stimulated burrowing nematode penetration of citrus roots. Heat denaturation of the lectins reversed their effect on penetration; however, incubation of nematodes in lectin (25 mug/ml) with 25 mM competitive sugars did not. The reason for enhanced penetration associated with lectins is unclear.

  7. Bioassay of tetrachlorvinphos for possible carcinogenicity.

    PubMed

    1978-01-01

    A bioassay of technical-grade tetrachlorvinphos for possible carcinogenicity was conducted by administering the test chemical in feed to Osborne-Mendel rats and B6C3F1 mice. Groups of 50 rats of each sex were administered tetrachlorvinphos at one of two doses for 80 weeks, then observed for 31 additional weeks. Time-weighted average doses were either 4,250 or 8,500 ppm. Matched controls consisted of groups of 10 untreated rats of each sex; pooled controls, used for statistical evaluation, consisted of the matched controls combined with 45 untreated male and 45 untreated female rats from similar bioassays of four other test chemicals. All surviving rats were killed at 111 weeks. Groups of 50 mice of each sex were administered tetrachlorvinphos at one of two doses, either 8,000 or 16,000 ppm, for 80 weeks, then observed for 12 additional weeks. Matched controls consisted of groups of 10 untreated mice of each sex; pooled controls, used for statistical evaluation, consisted of the matched controls combined with 40 untreated male and 40 untreated female mice from similar bioassays of four other test chemicals. All surviving mice were killed at 90-92 weeks. The mean body weights of the treated rats and mice were generally lower than those of the matched controls; however, the mortality rate was affected adversely by tetrachlorvinphos only in the male rats. Survival of all groups of rats and mice was adequate for meaningful statistical analyses of the incidence of tumors, except for a matched-control group of female rats for which the survival was abnormally low. In rats, C-cell adenoma of the thyroid showed a significant dose-related trend in the females, using pooled controls (controls 1/46, low-dose 2/50, high-dose 7/46, P=0.013), and by direct comparison, an increased incidence in the high-dose group (P=0.027). High incidences of C-cell hyperplasia in treated males and females further indicated a chemical-related effect on proliferative lesions of the thyroid

  8. Evaluation of a feline-specific multiplex, bead-based assay for detection of cytokines, chemokines, growth factors, and other immunologically active proteins in serum and plasma samples from cats.

    PubMed

    Halpin, Rachel E; Saunders, Rebecca S; Thompson, Beverly J; Rohde Newgent, Allison S; Amorim, Juliana; Melillo, Gabrielle N; DeClue, Amy E

    2016-05-01

    OBJECTIVE To evaluate a feline-specific multiplex, bead-based assay system for detection of recombinant and native proteins in serum samples and in EDTA-treated and heparinized plasma samples. SAMPLE Serum samples and EDTA-treated and heparinized plasma samples from 30 sick cats and 9 healthy client-owned cats and heparinized whole blood samples from 5 healthy purpose-bred cats. PROCEDURES Ability of the assay system to detect 19 recombinant and native immunologically active proteins in plasma and serum samples from healthy and purpose-bred cats was evaluated via spike-and-recovery tests, assessments of inter- and intra-assay variation, linearity results, and leukocyte stimulation. Effects of various concentrations of heparin and serum matrix solution on percentages of analytes recovered were also evaluated. Analyte concentrations in samples from healthy and sick cats were measured and compared between groups. RESULTS Percentages of analytes recovered were unsatisfactory for most assays. Serum and heparinized plasma samples yielded better recovery results than did EDTA-treated plasma samples. Use of serum matrix solution did not improve results. Use of heparin concentrations greater than the recommended range affected the results. Linearity of results was difficult to assess because of the poor recovery. For the analytes that were recovered sufficiently for assessment, linearity appeared to be reasonable despite the limited detection. CONCLUSIONS AND CLINICAL RELEVANCE Poor percentages of analytes recovered and adverse effects of sample protein matrix limited the usefulness of the multiplex, bead-based assay system for measurement of immunologically active proteins in solutions with high protein content; however, recovery results were fairly linear, potentially allowing evaluation of feline plasma or serum samples with high analyte concentrations.

  9. Bioassay-Directed Fractionation of Diesel and Biodiesel Emissions

    EPA Science Inventory

    Biofuels are being developed as alternatives to petroleum-derived products, but published research is contradictory regarding the mutagenic activity of such emissions relative to those from petroleum diesel. We performed bioassay-directed fractionation and analyzed the polycyclic...

  10. Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

    SciTech Connect

    Dr. X. Geroge Xu

    2011-01-28

    A radiation bioassay program relies on a set of standard human phantoms to calibrate and assess radioactivity levels inside a human body for radiation protection and nuclear medicine imaging purposes. However, the methodologies in the development and application of anthropomorphic phantoms, both physical and computational, had mostly remained the same for the past 40 years. We herein propose a 3-year research project to develop medical image-based physical and computational phantoms specifically for radiation bioassay applications involving internally deposited radionuclides. The broad, long-term objective of this research was to set the foundation for a systematic paradigm shift away from the anatomically crude phantoms in existence today to realistic and ultimately individual-specific bioassay methodologies. This long-term objective is expected to impact all areas of radiation bioassay involving nuclear power plants, U.S. DOE laboratories, and nuclear medicine clinics.

  11. PubChem BioAssay: 2017 update

    PubMed Central

    Wang, Yanli; Bryant, Stephen H.; Cheng, Tiejun; Wang, Jiyao; Gindulyte, Asta; Shoemaker, Benjamin A.; Thiessen, Paul A.; He, Siqian; Zhang, Jian

    2017-01-01

    PubChem's BioAssay database (https://pubchem.ncbi.nlm.nih.gov) has served as a public repository for small-molecule and RNAi screening data since 2004 providing open access of its data content to the community. PubChem accepts data submission from worldwide researchers at academia, industry and government agencies. PubChem also collaborates with other chemical biology database stakeholders with data exchange. With over a decade's development effort, it becomes an important information resource supporting drug discovery and chemical biology research. To facilitate data discovery, PubChem is integrated with all other databases at NCBI. In this work, we provide an update for the PubChem BioAssay database describing several recent development including added sources of research data, redesigned BioAssay record page, new BioAssay classification browser and new features in the Upload system facilitating data sharing. PMID:27899599

  12. In Vitro Androgen Bioassays as a Detection Method for Designer Androgens

    PubMed Central

    Cooper, Elliot R.; McGrath, Kristine C. Y.; Heather, Alison K.

    2013-01-01

    Androgens are the class of sex steroids responsible for male sexual characteristics, including increased muscle mass and decreased fat mass. Illicit use of androgen doping can be an attractive option for those looking to enhance sporting performance and/or physical appearance. The use of in vitro bioassays to detect androgens, especially designer or proandrogens, is becoming increasingly important in combating androgen doping associated with nutritional supplements. The nutritional sports supplement market has grown rapidly throughout the past decade. Many of these supplements contain androgens, designer androgens or proandrogens. Many designer or proandrogens cannot be detected by the standard highly-sensitive screening methods such as gas chromatography-mass spectrometry because their chemical structure is unknown. However, in vitro androgen bioassays can detect designer and proandrogens as these assays are not reliant on knowing the chemical structure but instead are based on androgen receptor activation. For these reasons, it may be advantageous to use routine androgen bioassay screening of nutraceutical samples to help curb the increasing problem of androgen doping. PMID:23389345

  13. Laboratory bioassays of vegetable oils as kairomonal phagostimulants for grasshoppers (Orthoptera: Acrididae).

    PubMed

    Latchininsky, Alexandre V; Schell, Scott P; Lockwood, Jeffrey A

    2007-10-01

    Vegetable oils have kairomonal attractant properties to grasshoppers primarily due to the presence of linoleic and linolenic fatty acids. These fatty acids are dietary essentials for grasshoppers and, once volatilized, can be detected by the insects' olfactory receptors. A laboratory bioassay method has been developed to identify vegetable oils that have fatty acid profiles similar to grasshoppers and that induce grasshopper attraction and feeding. Such oils could be useful kairomonal adjuvants and/or carriers for acridicide formulations. Three sets of laboratory bioassays demonstrated that the addition of a standard aliquot of different vegetable oils resulted in varying degrees of grasshopper feeding on otherwise neutral substrates. Addition of olive oil stimulated the greatest feeding in all three sets of assays, regardless of the age of the tested insects. Furthermore, addition of canola or flax oils markedly enhanced grasshopper feeding. These three oils--i.e., olive, canola, and flax oil--proved to be the best performing grasshopper stimulants. A second group of oils included rapeseed-flax mix and rapeseed oils; however, their performance was not as consistent as oils in the first group--especially with regard to nymphal feeding. A third group of oils consisted of soybean, corn, peanut, and sunflower oil. Theoretical expectations regarding these oils varied wildly, suggesting that the results of a single bioassay should be cautiously interpreted as being negative.

  14. Correction of Spray Concentration and Bioassay Cage Penetration Data

    DTIC Science & Technology

    2012-01-01

    analysis were deployed. Mosquito mortality was monitored using Townzen type bioassay cages (Townzen and Natvig 1973) (16 cm diam 3 4 cm depth; with T-310...into holding cups and mortality counts were made 24 h after treatment. Mosquitoes were considered dead if unresponsive to gentle prodding. Overall insect...Bioassay Cage Penetration Data Author(s): Bradley K. Fritz , W. Clint Hoffmann , Keith Haas , and Jane Bonds Source: Journal of the American Mosquito

  15. 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.

  16. Strategy for photostable proximity bioassays using lanthanides

    PubMed Central

    Haushalter, Jeanne P.; Faris, Gregory W.

    2011-01-01

    We report initial findings for research aimed at creating photostable lanthanide chelate reporters for proximity assays. These reporters take advantage of the nanometer scale distance dependence of fluorescence enhancement for molecules in the vicinity of noble metal nanoparticles and also capitalize on some unique properties of lanthanide chelates. This approach promises to lead to proximity assays that do not suffer from photobleaching and offer very high on/off enhancement ratios. Results for lanthanide chelates on silver island films and in colloidal suspensions are reported. Enhancement factors range from 1 to 2 orders of magnitude, with larger enhancements for strongly quenched lanthanides. PMID:17356638

  17. A rapid resazurin bioassay for assessing the toxicity of fungicides.

    PubMed

    Fai, Patricia Bi; Grant, Alastair

    2009-03-01

    Fungicides are widely used in agriculture, and released in large amounts to the environment. Methods used for antifungal susceptibility testing are cumbersome and time-consuming. As a result, very little attention has been paid to including fungal tests in the routine screening of pesticides and there are no reports in the literature of fungicide focussed effects directed analysis (EDA). In addition very little is known on the toxicity of fungicides to environmentally significant fungi. Here we report a rapid microplate-based resorufin fluorescence inhibition bioassay and compare it with a 24h microplate-based yeast growth inhibition bioassay using eight fungicides. The growth inhibition bioassay was sensitive, giving IC50 and IC90 values comparable to previously reported IC50 or MICs of these fungicides for Saccharomyces cerevisiae and other fungi. The resorufin fluorescence inhibition bioassay was both faster and more sensitive than the growth inhibition bioassay. Inhibitory concentrations obtained just after 30min of incubation with amphotericin B (AMB) and captan were at least a hundred fold lower than IC50s in the literature for fungi. The fluorescence bioassay showed only a small response to pyrazophos and thiabendazole but these only inhibited growth at high concentrations so this may reflect low sensitivity of S. cerevisiae to these particular fungicides. This bioassay can detect toxic effects of a range of fungicides from different chemical classes with different modes of action. It will be valuable for screening chemical libraries for fungicides and as a biomarker for detecting the effects of fungicides to non-target fungi.

  18. Soil bioassays and the {sup 129}I problem

    SciTech Connect

    Sheppard, S.C.

    1995-12-31

    Iodine-129 is a very long-lived radionuclide associated with spent nuclear fuel. Because {sup 129}I has a 10{sup 7}-year half-life, is very mobile in the environment and is a biologically essential element, it is the most limiting radionuclide affecting disposal of spent fuel. Traditionally, the potential impacts of {sup 129}I have been estimated for human receptors, with the implicit assumption that all other organisms are less at risk. Risk is the operative word, the objective for protection of humans is to protect individuals, whereas the objective for other biota is usually to protect populations. Here, {sup 129}I poses an interesting problem: the half-life is so long it is barely radioactive. Thus, the chemical toxicity may be more limiting than the radiological impact. A series of soil bioassays were employed, including a life-cycle plant (Brassica rapa) bioassay, a modified earthworm survival bioassay, a microarthropod colonization/survival bioassay, and a series of more common soil and aquatic bioassays. Chemical toxicity was indicated at soil concentrations as low as 5 mg kg{sup {minus}1}. At these levels, radiological impact on non-human biota would not be expected, and therefore the chemical toxicity effects are more critical. However, human food-chain model estimates show these levels, as pure {sup 129}I, would be unacceptable for human radiological exposure, so that for {sup 129}I, protection of the human environment should also be protective of non-human biota.

  19. Detection of Metal and Organometallic Compounds with Bioluminescent Bacterial Bioassays.

    PubMed

    Durand, M J; Hua, A; Jouanneau, S; Cregut, M; Thouand, G

    2015-10-17

    Chemical detection of metal and organometallic compounds is very specific and sensitive, but these techniques are time consuming and expensive. Although these techniques provide information about the concentrations of compounds, they fail to inform us about the toxicity of a sample. Because the toxic effects of metals and organometallic compounds are influenced by a multitude of environmental factors, such as pH, the presence of chelating agents, speciation, and organic matter, bioassays have been developed for ecotoxicological studies. Among these bioassays, recombinant luminescent bacteria have been developed over the past 20 years, and many of them are specific for the detection of metals and metalloids. These bioassays are simple to use, are inexpensive, and provide information on the bioavailable fraction of metals and organometals. Thus, they are an essential complementary tool for providing information beyond chemical analysis. In this chapter, we propose to investigate the detection of metals and organometallic compounds with bioluminescent bacterial bioassays and the applications of these bioassays to environmental samples. Graphical Abstract.

  20. [Investigation on pattern and methods of quality control for Chinese materia medica based on dao-di herbs and bioassay - bioassay for Coptis chinensis].

    PubMed

    Yan, Dan; Xiao, Xiao-he

    2011-05-01

    Establishment of bioassay methods is the technical issues to be faced with in the bioassay of Chinese materia medica. Taking the bioassay of Coptis chinensis Franch. as an example, the establishment process and application of the bioassay methods (including bio-potency and bio-activity fingerprint) were explained from the aspects of methodology, principle of selection, experimental design, method confirmation and data analysis. The common technologies were extracted and formed with the above aspects, so as to provide technical support for constructing pattern and method of the quality control for Chinese materia medica based on the dao-di herbs and bioassay.

  1. Carbon-14 bioassay for decommissioning of Hanford reactors.

    PubMed

    Carbaugh, Eugene H; Watson, David J

    2012-05-01

    The production reactors at the U.S. Department of Energy Hanford Site used large graphite piles as the moderator. As part of long-term decommissioning plans, the potential need for ¹⁴C radiobioassay of workers was identified. Technical issues associated with ¹⁴C bioassay and worker monitoring were investigated, including anticipated graphite characterization, potential intake scenarios, and the bioassay capabilities that may be required to support the decommissioning of the graphite piles. A combination of urine and feces sampling would likely be required for the absorption type S ¹⁴C anticipated to be encountered. However, the concentrations in the graphite piles appear to be sufficiently low that dosimetrically significant intakes of ¹⁴C are not credible, thus rendering moot the need for such bioassay.

  2. Carbon-14 Bioassay for Decommissioning of Hanford Reactors

    SciTech Connect

    Carbaugh, Eugene H.; Watson, David J.

    2012-05-01

    The old production reactors at the US Department of Energy Hanford Site used large graphite piles as the moderator. As part of long-term decommissioning plans, the potential need for 14C radiobioassay of workers was identified. Technical issues associated with 14C bioassay and worker monitoring were investigated, including anticipated graphite characterization, potential intake scenarios, and the bioassay capabilities that may be required to support the decommissioning of the graphite piles. A combination of urine and feces sampling would likely be required for the absorption type S 14C anticipated to be encountered. However the concentrations in the graphite piles appear to be sufficiently low that dosimetrically significant intakes of 14C are not credible, thus rendering moot the need for such bioassay.

  3. Internal dosimetry performing dose assessments via bioassay measurements

    SciTech Connect

    Bailey, K.M.

    1993-05-11

    The Internal Dosimetry Department at the Y-12 Plant maintains a state-of-the-art bioassay program managed under the guidance and regulations of the Department of Energy. The two major bioassay techniques currently used at Y-12 are the in vitro (urinalysis) and in vivo (lung counting) programs. Fecal analysis (as part of the in vitro program) is another alternative; however, since both urine and fecal analysis provide essentially the same capabilities for detecting exposures to uranium, the urinalysis is the main choice primarily for aesthetic reasons. The bioassay frequency is based on meeting NCRP 87 objectives which are to monitor the accumulation of radioactive material in exposed individuals, and to ensure that significant depositions are detected.

  4. Do we really need in-situ bioassays?

    SciTech Connect

    Salazar, M.H.; Salazar, S.M.

    1995-12-31

    In-situ bioassays are needed to validate the results from laboratory testing and to understand biological interactions. Standard laboratory protocols provide reproducible test results, and the precision of those tests can be mathematically defined. Significant correlations between toxic substances and levels of response (bioaccumulation and bioeffects) have also been demonstrated with natural field populations and suggest that the laboratory results can accurately predict field responses. An equal number of studies have shown a lack of correlation between laboratory bioassay results and responses of natural field populations. The best way to validate laboratory results is with manipulative field testing; i.e., in-situ bioassays with caged organisms. Bioaccumulation in transplanted bivalves has probably been the most frequently used form of an in-situ bioassay. The authors have refined those methods to include synoptic measurements of bioaccumulation and growth. Growth provides an easily-measured bioeffects endpoint and a means of calibrating bioaccumulation. Emphasis has been on minimizing the size range of test animals, repetitive measurements of individuals and standardization of test protocols for a variety of applications. They are now attempting to standardize criteria for accepting and interpreting data in the same way that laboratory bioassays have been standardized. Others have developed methods for in-situ bioassays using eggs, larvae, unicellular organisms, crustaceans, benthic invertebrates, bivalves, and fish. In the final analysis, the in-situ approach could be considered as an exposure system where any clinical measurements are possible. The most powerful approach would be to use the same species in laboratory and field experiments with the same endpoints.

  5. A novel magnetic bead-based assay with high sensitivity and selectivity for analysis of telomerase in exfoliated cells from patients with bladder and colon cancer.

    PubMed

    Rothacker, Julie; Ramsay, Robert G; Ciznadija, Daniel; Gras, Emma; Neylon, Craig B; Elwood, Ngaire J; Bouchier-Hayes, David; Gibbs, Peter; Rosenthal, Mark A; Nice, Edouard C

    2007-12-01

    Telomerase activity is elevated in more than 85% of cancer cells and absent in most of the normal cells and thus represents a potential cancer biomarker. We report its measurement in colon and bladder cancer cells captured using antibody-coated magnetic beads. The cells are lysed and telomerase activity is detected using a biosensor assay that employs an oligonucleotide containing the telomerase recognition sequence also covalently coupled to magnetic beads. Telomerase activity is measured by the incorporation of multiple biotinylated nucleotides at the 3'-end of the oligonucleotide strands during elongation which are then reacted with streptavidin-conjugated horseradish peroxidase. A luminescent signal is generated when hydrogen peroxidase is added in the presence of luminol and a signal enhancer. LOD experiments confirm sensitivity down to ten cancer cell equivalents. The telomerase assay reliably identified patient samples considered by an independent pathological review to contain cancer cells. Samples from normal healthy volunteers were all telomerase negative. The assay, which is amenable to automation, demonstrated high sensitivity and specificity in a small clinical cohort, making it of potential benefit as a first line assay for detection and monitoring of colon and bladder cancer.

  6. An emergency bioassay method for actinides in urine.

    PubMed

    Dai, Xiongxin; Kramer-Tremblay, Sheila

    2011-08-01

    A rapid bioassay method has been developed for the sequential measurements of actinides in human urine samples. The method involves actinide separation from a urine matrix by co-precipitation with hydrous titanium oxide (HTiO), followed by anion exchange and extraction chromatography column purification, and final counting by alpha spectrometry after cerium fluoride micro-precipitation. The minimal detectable activities for the method were determined to be 20 mBq L(-1) or less for plutonium, uranium, americium and curium isotopes, with an 8-h sample turn-around time. Spike tests showed that this method would meet the requirements for actinide bioassay following a radiation emergency.

  7. Optimization and application of a multiplex bead-based assay to quantify serotype-specific IgG against Streptococcus pneumoniae polysaccharides: response to the booster vaccine after immunization with the pneumococcal 7-valent conjugate vaccine.

    PubMed

    Elberse, Karin E M; Tcherniaeva, Irina; Berbers, Guy A M; Schouls, Leo M

    2010-04-01

    We describe the optimization and application of a multiplex bead-based assay (Luminex) to quantify antibodies against polysaccharides of 13 pneumococcal serotypes. In the optimized multiplex immunoassay (MIA), intravenous immune globulin was introduced as an in-house reference serum, and nonspecific reacting antibodies were adsorbed with the commercial product pneumococcal C polysaccharides Multi. The antibody concentrations were assessed in 188 serum samples obtained pre- and post-booster vaccination at 11 months after administration of a primary series of the pneumococcal seven-valent conjugate vaccine (PCV-7) at 2, 3, and 4 months of age. The results of the MIA were compared with those of the ELISA for the serotypes included in the seven-valent conjugated polysaccharide vaccine and for a non-vaccine serotype, serotype 6A. The geometric mean concentrations of the antibodies determined by MIA were slightly higher than those determined by ELISA. The correlations between the assays were good, with R(2) values ranging from 0.84 to 0.91 for all serotypes except serotype 19F, for which R(2) was 0.70. The concentrations of antibody against serotype 6A increased after the administration of PCV-7 due to cross-reactivity with serotype 6B. The differences between the results obtained by ELISA and MIA suggest that the internationally established protective threshold of 0.35 microg/ml should be reevaluated for use in the MIA and may need to be amended separately for each serotype.

  8. A microfluidic chip-based fluorescent biosensor for the sensitive and specific detection of label-free single-base mismatch via magnetic beads-based "sandwich" hybridization strategy.

    PubMed

    Wang, ZongWen; Fan, YingWei; Chen, JinFa; Guo, Ying; Wu, WeiHua; He, Ye; Xu, LiangJun; Fu, FengFu

    2013-08-01

    A novel microfluidic chip-based fluorescent DNA biosensor, which utilized the electrophoretic driving mode and magnetic beads-based "sandwich" hybridization strategy, was developed for the sensitive and ultra-specific detection of single-base mismatch DNA in this study. In comparison with previous biosensors, the proposed DNA biosensor has much more robust resistibility to the complex matrix of real saliva and serum samples, shorter analysis time, and much higher discrimination ability for the detection of single-base mismatch. These features, as well as its easiness of fabrication, operation convenience, stability, better reusability, and low cost, make it a promising alternative to the SNPs genotyping/detection in clinical diagnosis. By using the biosensor, we have successfully determined oral cancer-related DNA in saliva and serum samples without sample labeling and any preseparation or dilution with a detection limit of 5.6 × 10(-11) M, a RSD (n = 5) < 5% and a discrimination factor of 3.58-4.54 for one-base mismatch.

  9. A statistical treatment of bioassay pour fractions

    NASA Astrophysics Data System (ADS)

    Barengoltz, Jack; Hughes, David

    A bioassay is a method for estimating the number of bacterial spores on a spacecraft surface for the purpose of demonstrating compliance with planetary protection (PP) requirements (Ref. 1). The details of the process may be seen in the appropriate PP document (e.g., for NASA, Ref. 2). In general, the surface is mechanically sampled with a damp sterile swab or wipe. The completion of the process is colony formation in a growth medium in a plate (Petri dish); the colonies are counted. Consider a set of samples from randomly selected, known areas of one spacecraft surface, for simplicity. One may calculate the mean and standard deviation of the bioburden density, which is the ratio of counts to area sampled. The standard deviation represents an estimate of the variation from place to place of the true bioburden density commingled with the precision of the individual sample counts. The accuracy of individual sample results depends on the equipment used, the collection method, and the culturing method. One aspect that greatly influences the result is the pour fraction, which is the quantity of fluid added to the plates divided by the total fluid used in extracting spores from the sampling equipment. In an analysis of a single sample’s counts due to the pour fraction, one seeks to answer the question: What is the probability that if a certain number of spores are counted with a known pour fraction, that there are an additional number of spores in the part of the rinse not poured. This is given for specific values by the binomial distribution density, where detection (of culturable spores) is success and the probability of success is the pour fraction. A special summation over the binomial distribution, equivalent to adding for all possible values of the true total number of spores, is performed. This distribution when normalized will almost yield the desired quantity. It is the probability that the additional number of spores does not exceed a certain value. Of course

  10. Bioassay of complex mixtures of indoor air pollutants. Chapter 7

    SciTech Connect

    Lewtas, J.; Claxton, L.; Mumford, J.; Lofroth, G.

    1990-01-01

    There are several strategies for conducting bioassay studies of indoor air pollutant mixtures. One approach is to generate indoor pollutants from sources under laboratory conditions suitable for human, animal, or in vitro bioassay studies. This approach was used extensively to evaluate tobacco smoke and to a lesser extent for other indoor combustion sources such as kerosene heaters. A second approach is to simulate these complex mixtures by simpler mixtures of pure chemicals which can be used in biological studies. The third approach, which is described in more detail here, is to use bioassays in the direct evaluation of complex mixtures of indoor air pollutants. The mixtures of organics found indoors from combustion sources, building materials, household products and human activities are extremely complex. They consist of thousands of components which are not well characterized or quantified. Many of these mixtures and certain components are potential human carcinogens. The development of short-term bioassays to detect mutagens and potential carcinogens has facilitated studies of complex mixtures including air pollutants and combustion emissions. Chapter 7 will focus on the development and application of bacterial mutagenicity assays to complex mixtures of indoor air pollutants.

  11. Sensitive bioassay for detection of biologically active ricin in food

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential use of ricin as an agent of biological warfare highlights the need to develop fast and effective methods to detect biologically active ricin. The current “gold standard” for ricin detection is an in vivo mouse bioassay; however, this method is not practical to test on a large number of...

  12. Microplate Bioassay for Determining Substrate Selectivity of "Candida rugosa" Lipase

    ERIC Educational Resources Information Center

    Wang, Shi-zhen; Fang, Bai-shan

    2012-01-01

    Substrate selectivity of "Candida rugosa" lipase was tested using "p"-nitrophenyl esters of increasing chain length (C[subscript 1], C[subscript 7], C[subscript 15]) using the high-throughput screening method. A fast and easy 96-well microplate bioassay was developed to help students learn and practice biotechnological specificity screen. The…

  13. Plants as bioassay systems for monitoring atmospheric pollutants

    PubMed Central

    Feder, William A.

    1978-01-01

    Plant species act as natural bioindicators of atmospheric pollutants. Plants can be used as bioassay systems for monitoring atmospheric pollutants. Plant injury symptoms, altered growth and reproductive pattern, changes in yield and/or productivity, and changes in species distribution can be used singly or in combination as monitoring devices. The results must be accepted as semiquantitative, but within that constraint, air quality can be sufficiently well defined to enable the setting of air quality standards. Genetic variability of higher plant species has yielded cultivars which display a range of tolerance to gaseous and particulate atmospheric pollutants. Asexual propagation of these cultivars provides pollutant-sensitive and pollutant-tolerant plant material which can be grown on selected sites for observation. Gymnosperm and Angiosperm species as well as species of lichens and mosses have been used to establish field monitoring networks in Europe, Canada, and the United States. White pine, shade tobacco, mosses, and lichens have proven particularly useful as bioassay tools. Pollen from pollutant-sensitive and pollutant-tolerant plant cultivars has also been used as a sensitive laboratory bioassay tool for studying air quality. Epiphytic mosses are particularly efficient as monitors of particulate pollutants, especially heavy metals, some of which may act as chemical mutagens. The cost, complexity, and lack of reliability of instrumented systems for air quality monitoring make imperative the need to develop successful plant bioassay systems for monitoring air quality. PMID:738233

  14. US Army Radiological Bioassay and Dosimetry: The RBD software package

    SciTech Connect

    Eckerman, K. F.; Ward, R. C.; Maddox, L. B.

    1993-01-01

    The RBD (Radiological Bioassay and Dosimetry) software package was developed for the U. S. Army Material Command, Arlington, Virginia, to demonstrate compliance with the radiation protection guidance 10 CFR Part 20 (ref. 1). Designed to be run interactively on an IBM-compatible personal computer, RBD consists of a data base module to manage bioassay data and a computational module that incorporates algorithms for estimating radionuclide intake from either acute or chronic exposures based on measurement of the worker's rate of excretion of the radionuclide or the retained activity in the body. In estimating the intake,RBD uses a separate file for each radionuclide containing parametric representations of the retention and excretion functions. These files also contain dose-per-unit-intake coefficients used to compute the committed dose equivalent. For a given nuclide, if measurements exist for more than one type of assay, an auxiliary module, REPORT, estimates the intake by applying weights assigned in the nuclide file for each assay. Bioassay data and computed results (estimates of intake and committed dose equivalent) are stored in separate data bases, and the bioassay measurements used to compute a given result can be identified. The REPORT module creates a file containing committed effective dose equivalent for each individual that can be combined with the individual's external exposure.

  15. Using bioassays for testing seawater quality in Greece.

    PubMed

    Kungolos, A; Samaras, P; Koutseris, E

    2003-03-01

    The objective of this work was the assessment of seawater quality in Thermaikos Gulf, Pagassitikos Gulf and Skiathos island in Northern Aegean Sea by the use of bioassays. Two bioassays using marine organisms as indicators of seawater quality were applied in this study; the invertebrate Artemia franciscana and the marine bioluminescent bacterium Vibrio fischeri. Bioassays are required for the integrated evaluation of water pollution, as physical and chemical tests alone are not sufficient enough for the assessment of potential effects on aquatic organisms. According to the result of this study, improvement in coastal water quality of Thermaikos Gulf was observed between September 1997 and April-May 2000. However, coastal water quality of Pagassitikos Gulf varied during the test period; it was generally good during April-May 2000, while in October 1999 it was generally poor. Between the two bioassays that have been applied in this study, the Microtox test, where the marine bacterium V. fischeri was used as a test organism, was more sensitive in detecting toxicity in seawater.

  16. Assessment of acrylamide toxicity using a battery of standardised bioassays.

    PubMed

    Zovko, Mira; Vidaković-Cifrek, Željka; Cvetković, Želimira; Bošnir, Jasna; Šikić, Sandra

    2015-12-01

    Acrylamide is a monomer widely used as an intermediate in the production of organic chemicals, e.g. polyacrylamides (PAMs). Since PAMs are low cost chemicals with applications in various industries and waste- and drinking water treatment, a certain amount of non-polymerised acrylamide is expected to end up in waterways. PAMs are non-toxic but acrylamide induces neurotoxic effects in humans and genotoxic, reproductive, and carcinogenic effects in laboratory animals. In order to evaluate the effect of acrylamide on freshwater organisms, bioassays were conducted on four species: algae Desmodesmus subspicatus and Pseudokirchneriella subcapitata, duckweed Lemna minor and water flea Daphnia magna according to ISO (International Organization for Standardisation) standardised methods. This approach ensures the evaluation of acrylamide toxicity on organisms with different levels of organisation and the comparability of results, and it examines the value of using a battery of low-cost standardised bioassays in the monitoring of pollution and contamination of aquatic ecosystems. These results showed that EC50 values were lower for Desmodesmus subspicatus and Pseudokirchneriella subcapitata than for Daphnia magna and Lemna minor, which suggests an increased sensitivity of algae to acrylamide. According to the toxic unit approach, the values estimated by the Lemna minor and Daphnia magna bioassays, classify acrylamide as slightly toxic (TU=0-1; Class 1). The results obtained from algal bioassays (Desmodesmus subspicatus and Pseudokirchneriella subcapitata) revealed the toxic effect of acrylamide (TU=1-10; Class 2) on these organisms.

  17. Book Review: Bioassays with Arthropods: 2nd Edition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The technical book "Bioassays with Arthropods: 2nd Edition" (2007. Jacqueline L. Robertson, Robert M. Russell, Haiganoush K, Preisler and N. E. Nevin, Eds. CRC Press, Boca Raton, FL, 224 pp.) was reviewed for the scientific readership of the peer-reviewed publication Journal of Economic Entomology. ...

  18. USING BIOASSAYS TO EVALUATE THE PERFORMANCE OF RISK MANAGEMENT TECHNIQUES

    EPA Science Inventory

    Often, the performance of risk management techniques is evaluated by measuring the concentrations of the chemials of concern before and after risk management effoprts. However, using bioassays and chemical data provides a more robust understanding of the effectiveness of risk man...

  19. Statistical considerations in the analysis of data from replicated bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multiple-dose bioassay is generally the preferred method for characterizing virulence of insect pathogens. Linear regression of probit mortality on log dose enables estimation of LD50/LC50 and slope, the latter having substantial effect on LD90/95s (doses of considerable interest in pest management)...

  20. Concomitant information in bioassay and semi-parametric estimation.

    PubMed

    Kim, Peter T; Lee, Christine H

    2005-05-15

    This paper presents a flexible modern approach to handling concomitant information for estimating the relative potency parameter in quantitative bioassays. This is accomplished in a semi-parametric framework where the concomitant variable is included non-parametrically. Estimation is then performed using smoothing splines where the point and interval estimators of the relative potency parameter exhibits desirable asymptotic properties.

  1. 1. VIEW IN ROOM 125, BIOASSAY LABORATORY, SHOWN IS THE ...

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

    1. VIEW IN ROOM 125, BIOASSAY LABORATORY, SHOWN IS THE FIRST STEP IN A SIX-STEP PROCESS TO ANALYZE URINE SAMPLES FOR PLUTONIUM AND URANIUM CONTAMINATION. IN THIS STEP, NITRIC ACID IS ADDED TO SAMPLE, AND THE SAMPLE IS BOILED DOWN TO A WHITE POWDER. - Rocky Flats Plant, Health Physics Laboratory, On Central Avenue between Third & Fourth Streets, Golden, Jefferson County, CO

  2. GHSI EMERGENCY RADIONUCLIDE BIOASSAY LABORATORY NETWORK - SUMMARY OF THE SECOND EXERCISE.

    PubMed

    Li, Chunsheng; Bartizel, Christine; Battisti, Paolo; Böttger, Axel; Bouvier, Céline; Capote-Cuellar, Antonio; Carr, Zhanat; Hammond, Derek; Hartmann, Martina; Heikkinen, Tarja; Jones, Robert L; Kim, Eunjoo; Ko, Raymond; Koga, Roberto; Kukhta, Boris; Mitchell, Lorna; Morhard, Ryan; Paquet, Francois; Quayle, Debora; Rulik, Petr; Sadi, Baki; Sergei, Aleksanin; Sierra, Inmaculada; de Oliveira Sousa, Wanderson; Szabό, Gyula

    2016-08-29

    The Global Health Security Initiative (GHSI) established a laboratory network within the GHSI community to develop collective surge capacity for radionuclide bioassay in response to a radiological or nuclear emergency as a means of enhancing response capability, health outcomes and community resilience. GHSI partners conducted an exercise in collaboration with the WHO Radiation Emergency Medical Preparedness and Assistance Network and the IAEA Response and Assistance Network, to test the participating laboratories (18) for their capabilities in in vitro assay of biological samples, using a urine sample spiked with multiple high-risk radionuclides ((90)Sr, (106)Ru, (137)Cs, and (239)Pu). Laboratories were required to submit their reports within 72 h following receipt of the sample, using a pre-formatted template, on the procedures, methods and techniques used to identify and quantify the radionuclides in the sample, as well as the bioassay results with a 95% confidence interval. All of the participating laboratories identified and measured all or some of the radionuclides in the sample. However, gaps were identified in both the procedures used to assay multiple radionuclides in one sample, as well as in the methods or techniques used to assay specific radionuclides in urine. Two-third of the participating laboratories had difficulties in determining all the radionuclides in the sample. Results from this exercise indicate that challenges remain with respect to ensuring that results are delivered in a timely, consistent and reliable manner to support medical interventions. Laboratories within the networks are encouraged to work together to develop and maintain collective capabilities and capacity for emergency bioassay, which is an important component of radiation emergency response.

  3. Microbiological bioassay using Bacillus pumilus to detect tetracycline in milk.

    PubMed

    Tumini, Melisa; Nagel, Orlando Guillermo; Althaus, Rafael Lisandro

    2015-05-01

    The tetracyclines (TCs) are widely used in the treatment of several diseases of cattle and their residues may be present in milk. To control these residues it is necessary to have available inexpensive screening methods, user-friendly and capable of analysing a high number of samples. The purpose of this study was to design a bioassay of microbiological inhibition in microtiter plates with spores of Bacillus pumilus to detect TCs at concentrations corresponding to the Maximum Residue Limits (MRLs). Several complementary experiments were performed to design the bioassay. In the first study, we determined the concentration of spores that produce a change in the bioassay's relative absorbance in a short time period. Subsequently, we assessed the concentration of chloramphenicol required to decrease the detection limit (DL) of TCs at MRLs levels. Thereafter, specificity, DL and cross-specificity of the bioassay were estimated. The most appropriate microbiological inhibition assay had a B. pumilus concentration of 1.6 × 10(9) spores/ml, fortified with 2500 μg chloramphenicol/l (CAP) in Mueller Hinton culture medium using brilliant black and toluidine blue as redox indicator. This bioassay detected 117 μg chlortetracycline/l, 142 μg oxytetracycline/l and 105 μg tetracycline/l by means of a change in the indicator's colour in a period of 5 h. The method showed good specificity (97.9%) which decreased slightly (93.3%) in milk samples with high somatic cell counts (>250,000 cells/ml). Furthermore, other antimicrobials studied (except neomycin) must be present in milk at high concentrations (from >5 to >100 MRLs) to produce positive results in this assay, indicating a low cross specificity.

  4. Genotoxicity of leachates from a landfill using three bioassays.

    PubMed

    Cabrera, G L; Rodriguez, D M

    1999-05-19

    In the city of Queretaro, around 500 tons of solid wastes are produced everyday and are deposited in a landfill. This is the result of social and economic activities of human beings or from their normal physiological functions. As a result of rain, leachates are produced, which, if not handled and treated correctly, may pollute the underground water. Among the bioassays developed for the detection of mutagenicity in environmental pollutants, plant systems have been proven to be sensitive, cheap, and effective. The purpose of this study was to determine the presence of genotoxic agents in the leachates of the landfill of the city using three bioassays: Tradescantia-micronucleus (Trad-MCN), Tradescantia stamen hair mutations (Trad-SHM) and Allium root anaphase aberrations (AL-RAA) and make a comparison of the results in the three assays. Leachates were sampled during both the dry and rainy seasons. Plant cuttings of Tradescantia or the roots of Allium were treated by submerging them in the leachates. Three replicates of each sample were analyzed in each of the three bioassays. As expected the samples of leachates collected during the dry season showed a higher genotoxicity than those collected during the rainy season. In conclusion, there are substances present in the leachates capable of inducing genotoxicity in the plant assays. On the other hand, the plant assays showed different degrees of sensitivity: the more sensitive was the Trad-MCN bioassay and the less sensitive the Trad-SHM assay. Therefore, when analyzing environmental pollutants it is recommended to use a battery of bioassays.

  5. BioAssay Ontology (BAO): a semantic description of bioassays and high-throughput screening results

    PubMed Central

    2011-01-01

    Background High-throughput screening (HTS) is one of the main strategies to identify novel entry points for the development of small molecule chemical probes and drugs and is now commonly accessible to public sector research. Large amounts of data generated in HTS campaigns are submitted to public repositories such as PubChem, which is growing at an exponential rate. The diversity and quantity of available HTS assays and screening results pose enormous challenges to organizing, standardizing, integrating, and analyzing the datasets and thus to maximize the scientific and ultimately the public health impact of the huge investments made to implement public sector HTS capabilities. Novel approaches to organize, standardize and access HTS data are required to address these challenges. Results We developed the first ontology to describe HTS experiments and screening results using expressive description logic. The BioAssay Ontology (BAO) serves as a foundation for the standardization of HTS assays and data and as a semantic knowledge model. In this paper we show important examples of formalizing HTS domain knowledge and we point out the advantages of this approach. The ontology is available online at the NCBO bioportal http://bioportal.bioontology.org/ontologies/44531. Conclusions After a large manual curation effort, we loaded BAO-mapped data triples into a RDF database store and used a reasoner in several case studies to demonstrate the benefits of formalized domain knowledge representation in BAO. The examples illustrate semantic querying capabilities where BAO enables the retrieval of inferred search results that are relevant to a given query, but are not explicitly defined. BAO thus opens new functionality for annotating, querying, and analyzing HTS datasets and the potential for discovering new knowledge by means of inference. PMID:21702939

  6. A HAMP promoter bioassay system for identifying chemical compounds that modulate hepcidin expression.

    PubMed

    Kawabata, Hiroshi; Uchiyama, Tatsuki; Sakamoto, Soichiro; Kanda, Junya; Oishi, Shinya; Fujii, Nobutaka; Tomosugi, Naohisa; Kadowaki, Norimitsu; Takaori-Kondo, Akifumi

    2015-05-01

    Hepcidin is the central regulator of systemic iron homeostasis; dysregulation of hepcidin expression causes various iron metabolic disorders, including hereditary hemochromatosis and anemia of inflammation. To identify molecules that modulate hepcidin expression, we developed a bioassay system for hepcidin gene (HAMP) promoter activity by stable transfection of Hep3B hepatoma cells with an expression plasmid in which EGFP was linked to a 2.5-kb human HAMP promoter. Interleukin 6, bone morphogenetic protein 6 (BMP-6), and oncostatin M, well-characterized stimulators of the HAMP promoter, strongly enhanced the green fluorescence intensity of these cells. Dorsomorphin, heparin, and cobalt chloride, known inhibitors of hepcidin expression, significantly suppressed green fluorescence intensity, and these inhibitory effects were more prominent when the cells were stimulated with BMP-6. Employing this system, we screened 1,280 biologically active small molecules and found several candidate inhibitors of hepcidin expression. Apomorphine, benzamil, etoposide, CGS-15943, kenpaullone, and rutaecarpine (all at 10 μmol/L) significantly inhibited hepcidin mRNA expression by Hep3B cells without affecting cell viability. CGS-15943 was the strongest suppressor of BMP-6-induced hepcidin-25 secretion in these cells. We conclude that our newly developed hepcidin promoter bioassay system is useful for identifying and evaluating compounds that modulate hepcidin expression.

  7. Medium-term bioassays as alternative carcinogenicity test.

    PubMed

    Ito, N; Imaida, K; Tamano, S; Hagiwara, A; Shirai, T

    1998-07-01

    A medium-term liver bioassay system for rapid detection of carcinogenic agents using male F344 rats has been developed, in order to bridge the gap between long-term carcinogenicity tests and short-term screening assays. The system is fundamentally based on the two-stage hypothesis of carcinogenesis: initiation with diethylnitrosamine (200 mg/kg bw, i.p.) is followed by test chemical administration during the second, in combination with 2/3 partial hepatectomy. It requires only 8 weeks for animal experimental treatment and a further few weeks for quantitative analysis of immunohistochemically-demonstrated glutathione S-transferase placental form positive hepatic foci. A total of 291 chemicals/substances have already been analyzed in this laboratory and the efficacy of the system for hepatocarcinogens has thereby been well established. This bioassay is particularly useful for dose-response and chemical mixture studies, usually requiring large-scale experiments and also for evaluation of chemopreventive agents. Another bioassay, a medium-term multiorgan bioassay system, using 5 different chemical carcinogens, diethylnitrosamine (DEN), N-methylnitrosourea (MNU), N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), 1,2-dimethylhydrazine (DMH) and 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN), has also been established for rapid detection of not only hepatocarcinogens, but also other organ-target carcinogens. Rats were initially treated with a single i.p. administration of 100 mg/kg DEN, 4 i.p. administrations of 20 mg/kg MNU, 4 s.c. doses of 40 mg/kg DMH for 2 weeks and then 0.1% DHPN for 2 weeks. Test chemicals are administered after the carcinogens exposure. Animals were sacrificed at the end of week 36, and major organs were examined histologically. Carcinogenic activities of test chemicals were compared between the test chemical treated group and carcinogen exposures group (control group). It is increasingly becoming regarded that these bioassays are useful methods and are

  8. Application and Interpretation of Bioassay and Biomonitoring: A Planning Document.

    DTIC Science & Technology

    1987-10-13

    food sources but may differ among floral food sources. Extrapolation from the earthworm bioassay should take into account that the lower molecular ... extraction protocols , the results of which remain an item of debate. Until the concomitant influences of developing biological activity are included in...rhizosphere consists of a physicochemical milieu which is whilly and completely apart from what can be measured or indexed from simple extractions made

  9. Liquid versus solid phase bioassays for dredged material toxicity assessment.

    PubMed

    Casado-Martínez, M C; Fernández, N; Forja, J M; DelValls, T A

    2007-05-01

    Since 1994 the results of the analyses of key chemical compounds (trace metals, polychlorinated biphenyls and polycyclic aromatic hydrocarbons) and the comparison with the corresponding sediment quality guidelines (SQGs) are used in decision-making for dredged material management in Spain. Nonetheless in the last decades a tiered testing approach is promoted for assessing the physical and chemical characteristics of dredged sediments and their potential biological effects in the environment. Bioassays have been used for sediment toxicity assessment in Spain but few or no experiences are reported on harbour sediments. We studied the incidence of toxicity in the 7 d bioassay using rotifers (Brachionus plicatilis) and the 48 h bioassay using sea urchin (Paracentrotus lividus) embryos over a series of experiments employing 22 different elutriates. The relative performance of this exposure phase was not comparable to data on the 10-d acute toxicity test using the burrowing amphipod Corophium volutator and the polychaete Arenicola marina, carried out on the whole sediments. These results evidence the importance of the exposure route and the test selected in decision-making, as the toxicity registered for the undiluted elutriates was largely due to the different solubility of sediment-bound contaminants. This work and other studies indicate that for many sediments, a complete battery of test is recommended together with physico-chemical analyses to decide whether dredged sediments are suitable for open water disposal or not.

  10. Novel bioassay using Bacillus megaterium to detect tetracycline in milk.

    PubMed

    Tumini, Melisa; Nagel, Orlando G; Molina, Pilar; Althaus, Rafael L

    2016-01-01

    Tetracyclines are used for the prevention and control of dairy cattle diseases. Residues of these drugs can be excreted into milk. Thus, the aim of this study was to develop a microbiological method using Bacillus megaterium to detect tetracyclines (chlortetracycline, oxytetracycline and tetracycline) in milk. In order to approximate the limits of detection of the bioassay to the Maximum Residue Limit (100μg/l) for milk tetracycline, different concentrations of chloramphenicol (0, 1000, 1500 and 2000μg/l) were tested. The detection limits calculated were similar to the Maximum Residue Limits when a bioassay using B. megaterium ATCC 9885 spores (2.8×10(8)spores/ml) and chloramphenicol (2000μg/l) was utilized. This bioassay detects 105μg/l of chlortetracycline, 100μg/l of oxytetracycline and 134μg/l of tetracycline in 5h. Therefore, this method is suitable to be incorporated into a microbiological multi-residue system for the identification of tetracyclines in milk.

  11. Improved bioassay for detecting autoinducer of Rhodovulum sulfidophilum

    NASA Astrophysics Data System (ADS)

    Terada, T.; Kikuchi, Y.; Umekage, S.

    2015-02-01

    Quorum sensing is a bacterial gene regulation system that enables prompt environmental adaptation in response to cell density. Quorum sensing is driven by an extracellularly secreted chemical signal called autoinducer. Gram-negative bacteria produce one or several types of N-acylhomoserine lactone (AHL) as autoinducers. Our previous study suggests that the gram-negative marine photosynthetic bacterium Rhodovulum sulfidophilum produces AHL in the early stationary phase and plays a role in maintaining the bacterial cell aggregates called "floc". We performed conventional bioassay to identify AHL production by using Chromobacterium violaceum VIR07, which produces violet pigment (violacein) in response to AHL with side chains ranging from C10 to C18 in length. However, we were not able to observe the violacein with good reproducibility, suggesting that inhibitory chemical compounds co-existed in the AHL extract. Therefore, we improved the extraction method; the ethyl acetate-extracted AHLs were fractionated by using reverse phase TLC. By using the re-extracted AHLs for the bioassay, we observed an obvious production of violacein. This result clearly indicates that R. sulfidophilum produces AHLs with side chains ranging from C10 to C18 in length and suggests the utility of improved bioassay for AHL detection.

  12. Modeling development of inhibition zones in an agar diffusion bioassay.

    PubMed

    Chandrasekar, Vaishnavi; Knabel, Stephen J; Anantheswaran, Ramaswamy C

    2015-09-01

    A two-temperature agar diffusion bioassay is commonly used to quantify the concentration of nisin using Micrococcus luteus as the indicator microorganism. A finite element computational model based on Fick's second law of diffusion was used to predict the radius of the inhibition zone in this diffusion bioassay. The model developed was used to calculate nisin concentration profiles as a function of time and position within the agar. The minimum inhibitory concentration (MIC) of nisin against M. luteus was determined experimentally. The critical time (T c) for growth of M. luteus within the agar diffusion bioassay was experimentally determined using incubation studies with nisin. The radius of the inhibition zone was predicted from the computational model as the location where the predicted nisin concentration at T c was equal to MIC. The MIC was experimentally determined to be 0.156 μg mL(-1), and T c was determined to be 7 h. Good agreement (R (2) = 0.984) was obtained between model-predicted and experimentally determined inhibition zone radii.

  13. Potential sources of artefact in the co-axial bioassay.

    PubMed

    Gunn, L K; Piper, P J

    1991-10-22

    The apparent release of relaxant activity from airway epithelium (epithelium-derived relaxing factor, EpDRF) has been examined in a co-axial bioassay system. The endothelium-denuded rat aorta, placed inside either the epithelium-intact guinea-pig trachea or rabbit bronchus relaxed in response to acetylcholine. In a modification of the standard preparation, the airway was slit longitudinally and immobilised inside a silicone rubber tube. Under these conditions, the acetylcholine-induced relaxation was abolished. Under the conditions of the co-axial bioassay, the oxygen tension in the lumen of either airway tube was lower than that of the bathing fluid. Upon addition of acetylcholine at concentrations which caused relaxation in the co-axial bioassay, the oxygen tension inside the epithelium-intact, but not the epithelium-denuded guinea-pig trachea was depressed to levels which would have affected the contractile response of a rat aorta. We suggest that the assay of relaxant activity from airways using co-axial preparations may be complicated by changes in volume and oxygen tension in the lumen of the donor airway and discuss how such problems might be avoided.

  14. Factors affecting laboratory bioassays with diatomaceous earth on stored wheat: effect of insect density, grain quantity, and cracked kernel containment.

    PubMed

    Kavallieratos, Nickolas G; Athanassiou, Christos G; Mpakou, Flora D; Mpassoukou, Argyro E

    2007-10-01

    Laboratory bioassays were carried out to evaluate the effect of insect density (10, 30, 60, and 100 adults), wheat quantity (10, 30, 60, and 100 g), and cracked kernel containment (5, 15, 30, and 50%) on the efficacy of diatomaceous earth (DE). Three beetle species, Sitophilus oryzae (L.), Rhyzopertha dominica (F.), and Tribolium confusum Jacquelin du Val, as well as two DE formulations, Insecto and SilicoSec, and one DE enhanced with pyrethrum, PyriSec (all commercially available) were tested. In the first two series of bioassays, the three DE formulations were applied at three dose rates, 500, 1000 and 1,500 ppm. In the third series, the dose rates used were 500 and 1,000 ppm. Dead adults were counted 14 d later. For insect density, wheat quantity, and cracked kernel containment, significant differences were noted in mortality levels of the tested species among the three DE formulations and among doses. No significant differences were noted in the mortality levels among the four adult densities of any of the insects tested. The increase of wheat quantity used in the bioassays increased significantly adult mortality of T. confusum. The increase of cracked wheat containment decreased significantly adult mortality of S. oryzae.

  15. Toxicity of copper-spiked sediments to Tubifex tubifex (Oligochaeta, Tubificidae): Comparison of the 28-day reproductive bioassay with an early-life-stage bioassay

    SciTech Connect

    Vecchi, M.; Pasteris, A.; Bonomi, G. . Dipt. di Biologia Evoluzionistica Sperimentale); Reynoldson, T.B. . National Water Research Inst.)

    1999-06-01

    Two sediment bioassay methods using Tubifex tubifex (Mueller, 1774) as the test species were compared. The first was an adult reproduction test, the second an early-life-stage survival test. The duration of both bioassays is 28 d and the amount of work required was similar; they may be useful alternatives to each other in different circumstances (e.g., the early life stage bioassay could be carried out with smaller volumes of sediment). The two bioassays were performed simultaneously on copper-spiked sediments. Sediments from two freshwater and two terrestrial sites were used; five separate, nonsimultaneous experiments were performed, one for each sediment or soil and a further experiment with soil with a good supplement. In the adult bioassay, there were large differences in the production of cocoons, eggs, and young among the control treatments of the five experiments. There were also major differences in the NOEC and LOEC for copper between the tested substrates. The early life stage bioassay appears to be less sensitive to copper toxicity than the adult reproductive bioassay since NOECs and LOECs are higher for early survival than for the most sensitive endpoints of the adult bioassay in three experiments out of five.

  16. Microwave-accelerated bioassay technique for rapid and quantitative detection of biological and environmental samples.

    PubMed

    Mohammed, Muzaffer; Syed, Maleeha F; Aslan, Kadir

    2016-01-15

    Quantitative detection of molecules of interest from biological and environmental samples in a rapid manner, particularly with a relevant concentration range, is imperative to the timely assessment of human diseases and environmental issues. In this work, we employed the microwave-accelerated bioassay (MAB) technique, which is based on the combined use of circular bioassay platforms and microwave heating, for rapid and quantitative detection of Glial Fibrillary Acidic Protein (GFAP) and Shiga like toxin (STX 1). The proof-of-principle use of the MAB technique with the circular bioassay platforms for the rapid detection of GFAP in buffer based on colorimetric and fluorescence readouts was demonstrated with a 900W kitchen microwave. We also employed the MAB technique with a new microwave system (called the iCrystal system) for the detection of GFAP from mice with brain injuries and STX 1 from a city water stream. Control bioassays included the commercially available gold standard bioassay kits run at room temperature. Our results show that the lower limit of detection (LLOD) of the colorimetric and fluorescence based bioassays for GFAP was decreased by ~1000 times using the MAB technique and our circular bioassay platforms as compared to the commercially available bioassay kits. The overall bioassay time for GFAP and STX 1 was reduced from 4h using commercially available bioassay kits to 10min using the MAB technique.

  17. Microwave-Accelerated Bioassay Technique for Rapid and Quantitative Detection of Biological and Environmental Samples

    PubMed Central

    Mohammed, Muzaffer; Syed, Maleeha F.; Aslan, Kadir

    2015-01-01

    Quantitative detection of molecules of interest from biological and environmental samples in a rapid manner, particularly with a relevant concentration range, is imperative to the timely assessment of human diseases and environmental issues. In this work, we employed the microwave-accelerated bioassay (MAB) technique, which is based on the combined use of circular bioassay platforms and microwave heating, for rapid and quantitative detection of Glial Fibrillary Acidic Protein (GFAP) and Shiga like toxin (STX 1). The proof-of-principle use of the MAB technique with the circular bioassay platforms for the rapid detection of GFAP in buffer based on colorimetric and fluorescence readouts was demonstrated with a 900 W kitchen microwave. We also employed the MAB technique with a new microwave system (called the iCrystal system) for the detection of GFAP from mice with brain injuries and STX 1 from a city water stream. Control bioassays included the commercially available gold standard bioassay kits run at room temperature. Our results show that the lower limit of detection (LLOD) of the colorimetric and fluorescence based bioassays for GFAP was decreased by ~1,000 times using the MAB technique and our circular bioassay platforms as compared to the commercially available bioassay kits. The overall bioassay time for GFAP and STX 1 was reduced from 4 hours using commercially available bioassay kits to 10 minutes using the MAB technique. PMID:26356762

  18. [Determination of Escherichia coli Shiga-like toxins by means of the MTT bioassay].

    PubMed

    Hörmansdorfer, S; Gareis, M; Bauer, J; Mayr, A

    1995-09-01

    Tissue culture cells' metabolism and viability are measured by the mitochondrial reduction rate of a yellow tetrazolium salt (MTT) to blue formazan crystals in the MTT-bioassay. Thus the MTT-bioassay is a standardizable and reproducible bioassay for measuring cytotoxicity or cytostimulation. It is shown that the MTT-bioassay is also very suitable for determining bacterial cytotoxins using Escherichia coli's Shiga-like toxins as example. 177 strains of E. coli, isolated from carcasses and organs of cattle, are classified biochemically and tested for cytotoxin production by means of the MTT-bioassay. One of these strains is recognized as producer of Shiga-like toxin 2. 4 Enterohemolysin-producing strains of E. coli are cultivated from a feces sample of a diarrhoeic nubian ibex and identified as Shiga-like toxin 1 producers by help of the MTT-bioassay.

  19. Bioassay case study applying the maximin D-optimal design algorithm to the four-parameter logistic model.

    PubMed

    Coffey, Todd

    2015-01-01

    Cell-based potency assays play an important role in the characterization of biopharmaceuticals but they can be challenging to develop in part because of greater inherent variability than other analytical methods. Our objective is to select concentrations on a dose-response curve that will enhance assay robustness. We apply the maximin D-optimal design concept to the four-parameter logistic (4 PL) model and then derive and compute the maximin D-optimal design for a challenging bioassay using curves representative of assay variation. The selected concentration points from this 'best worst case' design adequately fit a variety of 4 PL shapes and demonstrate improved robustness.

  20. Bioassay of 4'-(chloroacetyl)-acetanilide for possible carcinogenicity.

    PubMed

    1979-01-01

    A bioassay for the possible carcinogenicity of 4'-(chloroacetyl)-acetanilide was conducted using Fischer 344 rats and B6C3F1 mice. 4'-(Chloroacetyl)-acetanilide was administered in the feed, at either of two concentrations, to groups of 50 male and 50 female animals of each species. Twenty animals of each sex and species were placed on test as controls. The high and low dietary concentrations of 4'-(chloroacetyl)-acetanilide were, respectively, 2,000 and 1,000 ppm for rats and 10,000 and 5,000 ppm for mice. The compound was administered for 87 weeks of a 102-week period in rats and for 90 weeks of a 105-week period in mice. Mice were killed at the end of the last week of compound administration, while rats were observed for 1 week after compound administration ceased. There were no significant positive associations between the concentration of 4'-(chloroacetyl)-acetanilide administered and mortality in rats or mice of either sex. Adequate numbers of animals in all groups survived sufficiently long to be at risk from late-developing tumors. Dose-related mean body weight depression was observed for males and females of both species, indicating that the concentrations of 4'-(chloroacetyl)-acetanilide administered to the animals in this bioassay may have approximated the maximum tolerated concentrations. None of the statistical tests for any site in rats of either sex or in male mice indicated a significant positive association between compound administration and tumor incidence. Although there was a significant positive association between the concentration of the compound administered and the incidences of hepatocellular adenomas in female mice, the Fischer exact comparisons were not significant. Under the conditions of this bioassay, 4'-(chloroacetyl)-acetanilide was not carcinogenic when administered in the diet to Fischer 344 rats or B6C3F1 mice of either sex.

  1. An emergency bioassay method for (210)Po in urine.

    PubMed

    Guérin, Nicolas; Dai, Xiongxin

    2015-09-01

    A rapid method was developed to efficiently measure (210)Po in urine samples in an emergency situation. Polonium-210 in small urine samples (10 mL) was spontaneously deposited on a stainless steel disc in 1 M HCl at room temperature for 4 h in a polyethylene bottle. The metallic disc was then counted for 4 h by alpha spectrometry. The developed method allowed the preparation of large sample batch in a short time. The method meets the requirements for an emergency bioassay procedure.

  2. Electroantennographic Bioassay as a Screening Tool for Host Plant Volatiles

    PubMed Central

    Beck, John J.; Light, Douglas M.; Gee, Wai S.

    2012-01-01

    Plant volatiles play an important role in plant-insect interactions. Herbivorous insects use plant volatiles, known as kairomones, to locate their host plant.1,2 When a host plant is an important agronomic commodity feeding damage by insect pests can inflict serious economic losses to growers. Accordingly, kairomones can be used as attractants to lure or confuse these insects and, thus, offer an environmentally friendly alternative to pesticides for insect control.3 Unfortunately, plants can emit a vast number volatiles with varying compositions and ratios of emissions dependent upon the phenology of the commodity or the time of day. This makes identification of biologically active components or blends of volatile components an arduous process. To help identify the bioactive components of host plant volatile emissions we employ the laboratory-based screening bioassay electroantennography (EAG). EAG is an effective tool to evaluate and record electrophysiologically the olfactory responses of an insect via their antennal receptors. The EAG screening process can help reduce the number of volatiles tested to identify promising bioactive components. However, EAG bioassays only provide information about activation of receptors. It does not provide information about the type of insect behavior the compound elicits; which could be as an attractant, repellent or other type of behavioral response. Volatiles eliciting a significant response by EAG, relative to an appropriate positive control, are typically taken on to further testing of behavioral responses of the insect pest. The experimental design presented will detail the methodology employed to screen almond-based host plant volatiles4,5 by measurement of the electrophysiological antennal responses of an adult insect pest navel orangeworm (Amyelois transitella) to single components and simple blends of components via EAG bioassay. The method utilizes two excised antennae placed across a "fork" electrode holder. The

  3. Aspirator Gun for High-Throughput Mosquito Bioassays

    DTIC Science & Technology

    2012-01-01

    surveillance of Aedes aegypti in San Juan, Puerto Rico. J Am Mosq Control Assoc 10:119–124. Dietrick EJ. 1961. An improved backpack motor fan for suction...Bioassays Author(s): Robert L. Aldridge, W. Wayne Wynn, Seth C. Britch, and Kenneth J. Linthicum Source: Journal of the American Mosquito Control ...Association, 28(1):65-68. 2012. Published By: The American Mosquito Control Association DOI: http://dx.doi.org/10.2987/11-6195.1 URL: http://www.bioone.org

  4. Application of the proposed new ICRP lung model to bioassay

    SciTech Connect

    Johnson, J.R.; James, A.C.; Hill, R.L.

    1992-05-01

    The new lung model being proposed by ICRP for use in radiation protection dosimetry requires the calculation of doses to separate regions of the respiratory tract, multiplying these doses by factors proportional to the risk per unit dose to each region, and summing over all regions of the lung to give a ``weighted`` lung dose. This paper compares the doses that would be calculated form bioassay measurements using the new model with those calculated using the current model, which essentially uses total lung burden to estimate lung dose.

  5. Application of the proposed new ICRP lung model to bioassay

    SciTech Connect

    Johnson, J.R.; James, A.C.; Hill, R.L.

    1992-05-01

    The new lung model being proposed by ICRP for use in radiation protection dosimetry requires the calculation of doses to separate regions of the respiratory tract, multiplying these doses by factors proportional to the risk per unit dose to each region, and summing over all regions of the lung to give a weighted'' lung dose. This paper compares the doses that would be calculated form bioassay measurements using the new model with those calculated using the current model, which essentially uses total lung burden to estimate lung dose.

  6. Microfluidic bioassay to characterize parasitic nematode phenotype and anthelmintic resistance.

    PubMed

    Chen, Baozhen; Deutmeyer, Alex; Carr, John; Robertson, Alan P; Martin, Richard J; Pandey, Santosh

    2011-01-01

    With increasing resistance to anti-parasitic drugs, it has become more important to detect and recognize phenotypes of resistant isolates. Molecular methods of detecting resistant isolates are limited at present. Here, we introduce a microfluidic bioassay to measure phenotype using parameters of nematode locomotion. We illustrate the technique on larvae of an animal parasite Oesophagostomum dentatum. Parameters of sinusoidal motion such as propagation velocity, wavelength, wave amplitude, and oscillation frequency depended on the levamisole-sensitivity of the isolate of parasitic nematode. The levamisole-sensitive isolate (SENS) had a mean wave amplitude of 135 μm, which was larger than 123 μm of the levamisole-resistant isolate (LEVR). SENS had a mean wavelength of 373 μm, which was less than 393 μm of LEVR. The mean propagation velocity of SENS, 149 μm s-1, was similar to LEVR, 143 μm s-1. The propagation velocity of the isolates was inhibited by levamisole in a concentration-dependent manner above 0.5 μm. The EC50 for SENS was 3 μm and the EC50 for LEVR was 10 μm. This microfluidic technology advances present-day nematode migration assays and provides a better quantification and increased drug sensitivity. It is anticipated that the bioassay will facilitate study of resistance to other anthelmintic drugs that affect locomotion.

  7. [Evaluation of Antilles fish ciguatoxicity by mouse and chick bioassays].

    PubMed

    Pottier, I; Vernoux, J P

    2003-03-01

    Ciguatera is a common seafood poisoning in Western Atlantic and French West Indies. Ciguatera fish poisoning in the Caribbean is a public health problem. A toxicological study was carried out on 178 Caribbean fish specimens (26 species) captured off Guadeloupe and Saint Barthelemy between 1993 and 1999. The mouse bioassay and the chick feeding test were used to control fish edibility. Ciguatoxins presence was assumed when symptomatology was typical of ciguatera in mouse and chick. Fishes were classified in three groups: non toxic fish (edible), low toxic fish (not edible) and toxic fish (not edible). 75% of fishes were non toxic. Toxic fish specimens belonged to four families of high trophic level carnivores: Carangidae, Lutjanidae, Serranidae et Sphyraenidae. Percentages of toxic fishes to humans reached 55% for Caranx latus and 33% for Caranx bartholomaei and Caranx lugubris. Only a significant correlation between weight and toxicity was only found for C. latus and snappers. Small carnivorous groupers (Serranidae) were also toxic. Atoxic fish species were (a) pelagic fish (Coryphaena hippurus, Auxis thazard and Euthynnus pelamis), (b) invertebrates feeders (Malacanthus plumieri, Balistes vetula), (c) small high-risk fish or (d) fish of edible benthic fish families. Liver of four fishes (Mycteroperca venenosa, Caranx bartholomaei, Seriola rivoliana, Gymnothorax funebris) contained ciguatoxins at a significant level although their flesh was safe. This study confirms the usefulness of mouse and chick bioassays for sanitary control of fish.

  8. Selecting a battery of bioassays for ecotoxicological characterization of wastes.

    PubMed

    Pandard, Pascal; Devillers, James; Charissou, Anne-Marie; Poulsen, Véronique; Jourdain, Marie-José; Férard, Jean-François; Grand, Cécile; Bispo, Antonio

    2006-06-15

    This study was conducted in France within the context of waste classification (Hazardous Waste Council Directive 91/689/EEC), and focused on "ecotoxic" property (H14). In 1998, an experimental test strategy was developed to assess ecotoxicological properties of wastes using a battery of six standardized bioassays. This combined direct and indirect approaches integrating two solid-phase tests: emergence and growth inhibition of Lactuca sativa (14 days), mortality of Eisenia fetida (14 days) and four standardized tests performed on water extracts from wastes: growth inhibition of Pseudokirchneriella subcapitata (3 days), inhibition of mobility of Daphnia magna (48 h), inhibition of reproduction of Ceriodaphnia dubia (7 days), inhibition of light emission of Vibrio fischeri (30 min). This study aimed to set up preliminary conclusions on relevancy of this experimental test strategy, based on data obtained since 1998. Results were analyzed from the combined use of Hierarchical Cluster Analysis, Principal Component Analysis and Nonlinear Mapping. These multivariate analyses clearly showed that it was possible to reduce this number of tests without changing the typology of the wastes. A battery of bioassays including one solid phase test and two tests performed on water extracts (L. sativa, V. fischeri and C. dubia) was found as an optimal solution for characterizing the toxicity of the studied wastes. This optimal battery represents a good basis for determining the H14 property.

  9. Vicia faba bioassay for environmental toxicity monitoring: A review.

    PubMed

    Iqbal, Munawar

    2016-02-01

    Higher plants are recognized as excellent genetic models to detect cytogenetic and mutagenic agents and are frequently used in environmental monitoring studies. Vicia faba (V. faba) bioassay have been used to study DNA damages i.e., chromosomal and nuclear aberrations induced by metallic compounds, pesticides, complex mixtures, petroleum derivates, toxins, nanoparticles and industrial effluents. The main advantages of using V. faba is its availability round the year, economical to use, easy to grow and handle; its use does not require sterile conditions, rate of cell division is fast, chromosomes are easy to score, less expensive and more sensitive as compared to other short-term tests that require pre-preparations. The V. faba test offers evaluation of different endpoints and tested agents can be classified as cytotoxic/genotoxic/mutagenic. This test also provides understanding about mechanism of action, whether the tested agent is clastogenic or aneugenic in nature. In view of advantages offered by V. faba test system, it is used extensively to assess toxic agents and has been emerged as an important bioassay for ecotoxicological studies. Based on the applications of V. faba test to assess the environmental quality, this article offers an overview of this test system and its efficiency in assessing the cytogenetic and mutagenic agents in different classes of the environmental concerns.

  10. Benthic invertebrate bioassays with toxic sediment and pore water

    USGS Publications Warehouse

    Giesy, John P.; Rosiu, Cornell J.; Graney, Robert L.; Henry, Mary G.

    1990-01-01

    The relative sensitivities of bioassays to determine the toxicity of sediments were investigated and three methods of making the sample dilutions required to generate dose-response relationships were compared. The assays studied were: (a) Microtox®, a 15-min assay ofPhotobacterium phosphoreum bioluminescence inhibition by pore water; (b) 48-h Daphnia magnalethality test in pore water; (c) 10-d subchronic assay of lethality to and reduction of weight gain by Chironomus tentans performed in either whole sediment or pore water; (d) 168-h acute lethality assay of Hexagenia limbata in either whole sediment or pore water. The three methods of diluting sediments were: (a) extracting pore water from the toxic location and dilution with pore water from the control station; (b) diluting whole sediment from the toxic location with control whole sediment from a reference location, then extracting pore water; and (c) diluting toxic, whole sediment with whole sediment from a reference location, then using the whole sediment in bioassays. Based on lethality, H. limbata was the most sensitive organism to the toxicity of Detroit River sediment. Lethality of D. magna in pore water was similar to that of H. limbata in whole sediment and can be used to predict effects of whole sediment toxicity to H. limbata. The concentration required to cause a 50% reduction in C. tentans growth (10-d EC50) was approximately that which caused 50% lethality of D. magna (48-h LC50) and was similar to the toxicity that restricts benthic invertebrate colonization of contaminated sediments. While the three dilution techniques gave similar results with some assays, they gave very different results in other assays. The dose-response relationships determined by the three dilution techniques would be expected to vary with sediment, toxicant and bioassay type, and the dose-response relationship derived from each technique needs to be interpreted accordingly.

  11. A Bioassay for Determining Resistance Levels in Tarnished Plant Bug Populations to Neonicotinoid Insecticides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A laboratory bioassay was developed and used to test field populations of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), for resistance development to the neonicitinoid insecticides imidacloprid (Trimax®) and thiamethoxam (Centric®). The bioassay determined LC50 values by feeding...

  12. Improved high-throughput bioassay for Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As we gain more information through functional genomic studies of Rhyzopertha dominica (F.), we need a high throughput bioassay system to screen potential biopesticides. R. dominica is an internal feeder during immature stages and presents unique challenges with traditional bioassay methods. Our pri...

  13. Profiling animal toxicants by automatically mining public bioassay data: a big data approach for computational toxicology.

    PubMed

    Zhang, Jun; Hsieh, Jui-Hua; Zhu, Hao

    2014-01-01

    In vitro bioassays have been developed and are currently being evaluated as potential alternatives to traditional animal toxicity models. Already, the progress of high throughput screening techniques has resulted in an enormous amount of publicly available bioassay data having been generated for a large collection of compounds. When a compound is tested using a collection of various bioassays, all the testing results can be considered as providing a unique bio-profile for this compound, which records the responses induced when the compound interacts with different cellular systems or biological targets. Profiling compounds of environmental or pharmaceutical interest using useful toxicity bioassay data is a promising method to study complex animal toxicity. In this study, we developed an automatic virtual profiling tool to evaluate potential animal toxicants. First, we automatically acquired all PubChem bioassay data for a set of 4,841 compounds with publicly available rat acute toxicity results. Next, we developed a scoring system to evaluate the relevance between these extracted bioassays and animal acute toxicity. Finally, the top ranked bioassays were selected to profile the compounds of interest. The resulting response profiles proved to be useful to prioritize untested compounds for their animal toxicity potentials and form a potential in vitro toxicity testing panel. The protocol developed in this study could be combined with structure-activity approaches and used to explore additional publicly available bioassay datasets for modeling a broader range of animal toxicities.

  14. Comparison of two mosquito bioassay methods for the estimate of minimum effective dose in repellents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is expected that laboratory-based repellent bioassays should reliably evaluate the efficacy of compounds that deter mosquito feeding behavior. The variety of repellent bioassays available allows for flexibility in design, but makes it difficult to compare any two methods, including in vitro and i...

  15. Resistance monitoring of Heliothis virescens to pyramided cotton varieties with a hydrateable, artificial cotton leaf bioassay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proof of concept was demonstrated for a practical, off the shelf bioassay to monitor for tobacco budworm resistance to pyramided Bt cotton using plant eluants. The bioassay was based on a previously described feeding disruption test using hydrateable artificial diet containing a blue indicator dye, ...

  16. Worldwide bioassay data resources for plutonium/americium internal dosimetry studies.

    PubMed

    Miller, G; Riddell, A E; Filipy, R; Bertelli, L; Little, T; Guilmette, R

    2007-01-01

    Biokinetic models are the scientific underpinning of internal dosimetry and depend, ultimately, for their scientific validation on comparisons with human bioassay data. Three significant plutonium/americium bioassay databases, known to the authors, are described: (1) Sellafield, (2) Los Alamos and (3) the United States Transuranium Registry. A case is made for a uniform standard for database format, and the XML standard is discussed.

  17. Immunochemical technologies for replacement of rodent bioassays in sensitive detection of toxins in foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rapid sensitive assays for biothreat toxins that can be used to detect intentionally contaminated foods are now typically performed via bioassay in live mice. While bioassay provides essential data on bioavailability, animal models are technically, fiscally, and ethically challenging. Through carefu...

  18. Evaluation of the mutagenicity and carcinogenicity of motor vehicle emissions in short-term bioassays.

    PubMed

    Lewtas, J

    1983-01-01

    Incomplete combustion of fuel in motor vehicles results in the emission of submicron carbonaceous particles which, after cooling and dilution, contain varying quantities of extractable organic constituents. These organics are mutagenic in bacteria. Confirmatory bioassays in mammalian cells provide the capability of detecting chromosomal and DNA damage in addition to gene mutations. In order to evaluate the mutagenicity of these organics in mammalian cells, extractable organics from particle emissions from several diesel and gasoline vehicles were compared in a battery of microbial, mammalian cell and in vivo bioassays. The mammalian cell mutagenicity bioassays were selected to detect gene mutations, DNA damage, and chromosomal effects. Carcinogenesis bioassays conducted included short-term assays for oncogenic transformation and skin tumorigenesis. The results in different assay systems are compared both qualitatively and quantitatively. Good quantitative correlations were observed between several mutagenesis and carcinogenesis bioassays for this series of diesel and gasoline emissions.

  19. Harvester ant bioassay for assessing hazardous chemical waste sites

    SciTech Connect

    Gano, K.A.; Carlile, D.W.; Rogers, L.E.

    1984-12-01

    A technique was developed for using harvester ants, Pogonomyrmex owhyeei, in terrestrial bioassays. Procedures were developed for maintaining stock populations, handling ants, and exposing ants to toxic materials. Relative toxicities were determined by exposing ants to 10 different materials. These materials included three insecticides, Endrin, Aldrin, and Dieldrin; one herbicide, 2,4-D; three oil-like compounds, wood preservative, drilling fluid, and slop oil; and three heavy metals, copper, zinc, and cadmium. Ants were exposed in petri dishes containing soil amended with a particular toxicant. Under these test conditions, ants showed no sensitivity to the metals or 2,4-D. Ants were sensitive to the insecticides and oils in repeated tests, and relative toxicity remained consistent throughout. Aldrin was the most toxic material, followed by Dieldrin, Endrin, wood preservative, drilling fluid, and slop oil. 10 refs., 2 figs., 2 tabs.

  20. Comprehensive integration of homogeneous bioassays via centrifugo-pneumatic cascading.

    PubMed

    Godino, Neus; Gorkin, Robert; Linares, Ana V; Burger, Robert; Ducrée, Jens

    2013-02-21

    This work for the first time presents the full integration and automation concept for a range of bioassays leveraged by cascading a centrifugo-pneumatic valving scheme to sequentially move several liquids through shared channel segments for multi-step sample preparation into the detection zone. This novel centrifugo-pneumatic liquid handling significantly simplifies system manufacture by obviating the need for complex surface functionalization procedures or hybrid material integration, as it is common in conventional valving methods such as capillary burst valves or sacrificial valves. Based on the centrifugo-pneumatic valving scheme, this work presents a toolkit of operational elements implementing liquid loading/transfer, metering, mixing and sedimentation in a microstructured polymer disc. As a proof of concept for the broad class of homogeneous bioassays, the full integration and automation of a colorimetric nitrate/nitrite test for the detection of clinically relevant nitric oxide (NO) in whole blood is implemented. First, 40 μL of plasma is extracted from a 100 μL sample of human blood, incubated for one hour with the enzymatic mixture (60 μL), and finally reacted with 100 μL of colorimetric (Greiss) reagents. Following just a single loading phase at the beginning of the process, all of these steps are automated through the centrifugo-pneumatic cascade with a high level of flow control and synchronization. Our system shows good correlation with controls up to 50 μM of nitrate, which adequately covers the healthy human range (4 to 45.3 μM).

  1. Susceptibility of cat fleas (Siphonaptera: Pulicidae) to fipronil and imidacloprid using adult and larval bioassays.

    PubMed

    Rust, M K; Vetter, R; Denholm, I; Blagburn, B; Williamson, M S; Kopp, S; Coleman, G; Hostetler, J; Davis, W; Mencke, N; Rees, R; Foit, S; Tetzner, K

    2014-05-01

    The monitoring of the susceptibility offleas to insecticides has typically been conducted by exposing adults on treated surfaces. Other methods such as topical applications of insecticides to adults and larval bioassays on treated rearing media have been developed. Unfortunately, baseline responses of susceptible strains of cat flea, Ctenocephalides felis (Bouchè), except for imidacloprid, have not been determined for all on-animal therapies and new classes of chemistry now being used. However, the relationship between adult and larval bioassays of fleas has not been previously investigated. The adult and larval bioassays of fipronil and imidacloprid were compared for both field-collected isolates and laboratory strains. Adult topical bioassays of fipronil and imidacloprid to laboratory strains and field-collected isolates demonstrated that LD50s of fipronil and imidacloprid ranged from 0.11 to 0.40 nanograms per flea and 0.02 to 0.18 nanograms per flea, respectively. Resistance ratios for fipronil and imidacloprid ranged from 0.11 to 2.21. Based on the larval bioassay published for imidacloprid, a larval bioassay was established for fipronil and reported in this article. The ranges of the LC50s of fipronil and imidacloprid in the larval rearing media were 0.07-0.16 and 0.11-0.21 ppm, respectively. Resistance ratios for adult and larval bioassays ranged from 0.11 to 2.2 and 0.58 to 1.75, respectively. Both adult and larval bioassays provided similar patterns for fipronil and imidacloprid. Although the adult bioassays permitted a more precise dosage applied, the larval bioassays allowed for testing isolates without the need to maintain on synthetic or natural hosts.

  2. 9 CFR 147.16 - Procedure for the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... mycoplasma reactors by in vivo bio-assay (enrichment). 147.16 Section 147.16 Animals and Animal Products... the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment). This procedure has been shown... publications: (a) Bigland, C. H. and A. J. DaMassa, “A Bio-Assay for Mycoplasma Gallisepticum.” In:...

  3. 9 CFR 147.16 - Procedure for the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... mycoplasma reactors by in vivo bio-assay (enrichment). 147.16 Section 147.16 Animals and Animal Products... the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment). This procedure has been shown... publications: (a) Bigland, C. H. and A. J. DaMassa, “A Bio-Assay for Mycoplasma Gallisepticum.” In:...

  4. 9 CFR 147.16 - Procedure for the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... mycoplasma reactors by in vivo bio-assay (enrichment). 147.16 Section 147.16 Animals and Animal Products... the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment). This procedure has been shown... publications: (a) Bigland, C. H. and A. J. DaMassa, “A Bio-Assay for Mycoplasma Gallisepticum.” In:...

  5. Establishment of a bioassay for the toxicity evaluation and quality control of Aconitum herbs.

    PubMed

    Qin, Yi; Wang, Jia-bo; Zhao, Yan-ling; Shan, Li-mei; Li, Bao-cai; Fang, Fang; Jin, Cheng; Xiao, Xiao-he

    2012-01-15

    Currently, no bioassay is available for evaluating the toxicity of Aconitum herbs, which are well known for their lethal cardiotoxicity and neurotoxicity. In this study, we established a bioassay to evaluate the toxicity of Aconitum herbs. Test sample and standard solutions were administered to rats by intravenous infusion to determine their minimum lethal doses (MLD). Toxic potency was calculated by comparing the MLD. The experimental conditions of the method were optimized and standardized to ensure the precision and reliability of the bioassay. The application of the standardized bioassay was then tested by analyzing 18 samples of Aconitum herbs. Additionally, three major toxic alkaloids (aconitine, mesaconitine, and hypaconitine) in Aconitum herbs were analyzed using a liquid chromatographic method, which is the current method of choice for evaluating the toxicity of Aconitum herbs. We found that for all Aconitum herbs, the total toxicity of the extract was greater than the toxicity of the three alkaloids. Therefore, these three alkaloids failed to account for the total toxicity of Aconitum herbs. Compared with individual chemical analysis methods, the chief advantage of the bioassay is that it characterizes the total toxicity of Aconitum herbs. An incorrect toxicity evaluation caused by quantitative analysis of the three alkaloids might be effectively avoided by performing this bioassay. This study revealed that the bioassay is a powerful method for the safety assessment of Aconitum herbs.

  6. A bioassay to evaluate the activity of chemical stimuli from grape berries on the oviposition of Lobesia botrana (Lepidoptera: Tortricidae).

    PubMed

    Maher, N; Thiéry, D

    2004-02-01

    A two-choice bioassay was developed to evaluate the role of host-plant berry compounds on the oviposition site acceptance of the generalist moth Lobesia botrana (Denis & Shiffermüller). A key feature was the lining of the bioassay arena with felt which focused oviposition on the test substrates. Initial experiments comparing substrates with different physical features indicated that smooth textures and spherical shapes with interstices favour oviposition. Artificial oviposition substrates were thus constructed with glass spheres in order to test the behavioural activity of grapevine berry extracts. Only polar extracts obtained by soaking berries in methanol or water stimulated oviposition (more eggs were laid on the extract-treated substrate than on the control substrate), whereas more apolar ones obtained with chloroform or hexane had no significant effect. The prior removal of epicuticular waxes from grape berries before extraction did not enhance the stimulatory activity of the methanol extract. The oviposition response to this extract was dose-dependent. It is concluded that polar compounds present on grape berries act as oviposition stimulants for L. botrana.

  7. Validation and application of a robust yeast estrogen bioassay for the screening of estrogenic activity in animal feed.

    PubMed

    Bovee, Toine F H; Bor, Gerrit; Heskamp, Henri H; Hoogenboom, Ron L A P; Nielen, Michel W F

    2006-06-01

    Previously we described the construction and properties of a rapid yeast bioassay stably expressing human estrogen receptor alpha (hERalpha) and yeast enhanced green fluorescent protein (yEGFP), the latter in response to estrogens. In the present study this yeast estrogen assay was validated as a qualitative screening method for the determination of estrogenic activity in animal feed. This validation was performed according to EC Decision 2002/657. Twenty blank animal feed samples, including milk replacers and wet and dry feed samples, were spiked with 17beta-estradiol (E2beta) at 5 ng g(-1), 17alpha-ethynylestradiol (EE2) at 5 ng g(-1), diethylstilbestrol (DES) at 10 ng g(-1), zearalenone at 1.25 microg g(-1) or equal at 200 microg g(-1). All of these blank and low estrogen spiked feed samples fulfilled the CCalpha and CCbeta criterions, meaning that all 20 blank feed samples gave a signal below the determined decision limit CCalpha and were thus classified as compliant, and at least 19 out of the 20 spiked samples gave a signal above this CCalpha (beta = 5%) and were thus classified as suspect. The method was specific and estrogens in feed were stable for up to 98 days. In this study we also present long-term performance data and several examples of estrogens found in the routine screening of animal feed. This is the first successful example of a developed, validated and applied bioassay for the screening of hormonal substances in feed.

  8. [Application of bioassay in quality control of Chinese materia medica-taking Radix Isatidis as an example].

    PubMed

    Yan, Dan; Ren, Yongshen; Luo, Jiaoyang; Li, Hanbing; Feng, Xue; Xiao, Xiaohe

    2010-10-01

    Bioassay, which construct the characteristics consistents with Chinese medical science, is the core mode and methods for the quality control of Chinese materia medica. Taking the bioassay of Radix Isatidis as an example, the contribution, status and application of bioassay in the quality control of Chinese materia medica were introduced in this article, and two key issue (the selection of reference and measurement methods) in the process of establishing bioassay were also explained. This article expects to provide a reference for the development and improvement of the bioassay of Chinese materia medica in a practical manipulation level.

  9. Toxicity assessment for petroleum-contaminated soil using terrestrial invertebrates and plant bioassays.

    PubMed

    Hentati, Olfa; Lachhab, Radhia; Ayadi, Mariem; Ksibi, Mohamed

    2013-04-01

    The assessment of soil quality after a chemical or oil spill and/or remediation effort may be measured by evaluating the toxicity of soil organisms. To enhance our understanding of the soil quality resulting from laboratory and oil field spill remediation, we assessed toxicity levels by using earthworms and springtails testing and plant growth experiments. Total petroleum hydrocarbons (TPH)-contaminated soil samples were collected from an oilfield in Sfax, Tunisia. Two types of bioassays were performed. The first assessed the toxicity of spiked crude oil (API gravity 32) in Organization for Economic Co-operation and Development artificial soil. The second evaluated the habitat function through the avoidance responses of earthworms and springtails and the ability of Avena sativa to grow in TPH-contaminated soils diluted with farmland soil. The EC50 of petroleum-contaminated soil for earthworms was 644 mg of TPH/kg of soil at 14 days, with 67 % of the earthworms dying after 14 days when the TPH content reached 1,000 mg/kg. The average germination rate, calculated 8 days after sowing, varied between 64 and 74 % in low contaminated soils and less than 50 % in highly contaminated soils.

  10. Influence of housing conditions for mice on the results of a dermal oncogenicity bioassay.

    PubMed

    DePass, L R; Weil, C S; Ballantyne, B; Lewis, S C; Losco, P E; Reid, J B; Simon, G S

    1986-11-01

    Male C3H/HeJ mice were thrice weekly given 25 microliter applications of 0.25, 0.05, or 0.01% (w/w) benzo(a)pyrene (BaP) in acetone, or acetone alone, to clipped dorsal skin from 12 to 14 weeks of age for the remainder of their life spans. There were two groups of 40 mice for each treatment regimen, one group being housed in conventional stainless-steel wire mesh cages and the other in polycarbonate cages with wood shavings held in an enclosed ventilated cabinet. Under both housing conditions, tumor incidence was directly related and latency inversely related to BaP concentration. The time-adjusted incidence of epidermal neoplasms was significantly greater for the groups housed in polycarbonate cages. Mortality rates were directly related to BaP concentration and were significantly enhanced by the polycarbonate-cage housing conditions for the high and intermediate concentrations. Survival patterns for the two acetone control groups were similar. These findings indicate that differences in housing conditions can influence both the incidence and the latency of local neoplasms produced in response to the chronic application of a carcinogen in dermal oncogenesis bioassays.

  11. A new highly specific and robust yeast androgen bioassay for the detection of agonists and antagonists.

    PubMed

    Bovee, Toine F H; Helsdingen, Richard J R; Hamers, Astrid R M; van Duursen, Majorie B M; Nielen, Michel W F; Hoogenboom, Ron L A P

    2007-11-01

    Public concern about the presence of natural and anthropogenic compounds which affect human health by modulating normal endocrine functions is continuously growing. Fast and simple high-throughput screening methods for the detection of hormone activities are thus indispensable. During the last two decades, a panel of different in vitro assays has been developed, mainly for compounds with an estrogenic mode of action. Here we describe the development of an androgen transcription activation assay that is easy to use in routine screening. Recombinant yeast cells were constructed that express the human androgen receptor and yeast enhanced green fluorescent protein (yEGFP), the latter in response to androgens. Compared with other reporters, the yEGFP reporter protein is very convenient because it is directly measurable in intact living cells, i.e., cell wall disruption and the addition of a substrate are not needed. When yeast was exposed to 17beta-testosterone, the concentration where half-maximal activation is reached (EC(50)) was 50 nM. The relative androgenic potencies, defined as the ratio between the EC(50) of 17beta-testosterone and the EC(50) of the compound, of 5alpha-dihydrotestosterone, methyltrienolone, and 17beta-boldenone are 2.3, 1.4, and 0.15 respectively. The results presented in this paper demonstrate that this new yeast androgen bioassay is fast, sensitive, and very specific and also suited to detect compounds that have an antiandrogenic mode of action.

  12. A new highly specific and robust yeast androgen bioassay for the detection of agonists and antagonists

    PubMed Central

    Helsdingen, Richard J. R.; Hamers, Astrid R. M.; van Duursen, Majorie B. M.; Nielen, Michel W. F.; Hoogenboom, Ron L. A. P.

    2007-01-01

    Public concern about the presence of natural and anthropogenic compounds which affect human health by modulating normal endocrine functions is continuously growing. Fast and simple high-throughput screening methods for the detection of hormone activities are thus indispensable. During the last two decades, a panel of different in vitro assays has been developed, mainly for compounds with an estrogenic mode of action. Here we describe the development of an androgen transcription activation assay that is easy to use in routine screening. Recombinant yeast cells were constructed that express the human androgen receptor and yeast enhanced green fluorescent protein (yEGFP), the latter in response to androgens. Compared with other reporters, the yEGFP reporter protein is very convenient because it is directly measurable in intact living cells, i.e., cell wall disruption and the addition of a substrate are not needed. When yeast was exposed to 17β-testosterone, the concentration where half-maximal activation is reached (EC50) was 50 nM. The relative androgenic potencies, defined as the ratio between the EC50 of 17β-testosterone and the EC50 of the compound, of 5α-dihydrotestosterone, methyltrienolone, and 17β-boldenone are 2.3, 1.4, and 0.15 respectively. The results presented in this paper demonstrate that this new yeast androgen bioassay is fast, sensitive, and very specific and also suited to detect compounds that have an antiandrogenic mode of action. PMID:17849102

  13. Methods to improve routine bioassay monitoring for freshly separated, poorly transported plutonium

    SciTech Connect

    Bihl, D.E.; Lynch, T.P.; Carbaugh, E.H.; Sula, M.J.

    1988-09-01

    Several human cases involving inhalation of plutonium oxide at Hanford have shown clearance half-times from the lung that are much longer than the 500-day half-time recommended for class Y plutonium in Publication 30 of the International Commission on Radiological Protection(ICRP). The more tenaciously retained material is referred to as super class Y plutonium. The ability to detect super class Y plutonium by current routine bioassay measurements is shown to be poor. Pacific Northwest Laboratory staff involved in the Hanford Internal Dosimetry Program investigated four methods to se if improvements in routine monitoring of workers for fresh super class Y plutonium are feasible. The methods were lung counting, urine sampling, fecal sampling, and use of diethylenetriaminepentaacetate (DTPA) to enhance urinary excretion. Use of DTPA was determined to be not feasible. Routine fecal sampling was found to be feasible but not recommended. Recommendations were made to improve the detection level for routine annual urinalysis and routine annual lung counting. 12 refs., 9 figs., 7 tabs.

  14. Analyzing bioassay data using Bayesian methods--a primer.

    PubMed

    Miller, G; Inkret, W C; Schillaci, M E; Martz, H F; Little, T T

    2000-06-01

    The classical statistics approach used in health physics for the interpretation of measurements is deficient in that it does not take into account "needle in a haystack" effects, that is, correct identification of events that are rare in a population. This is often the case in health physics measurements, and the false positive fraction (the fraction of results measuring positive that are actually zero) is often very large using the prescriptions of classical statistics. Bayesian statistics provides a methodology to minimize the number of incorrect decisions (wrong calls): false positives and false negatives. We present the basic method and a heuristic discussion. Examples are given using numerically generated and real bioassay data for tritium. Various analytical models are used to fit the prior probability distribution in order to test the sensitivity to choice of model. Parametric studies show that for typical situations involving rare events the normalized Bayesian decision level k(alpha) = Lc/sigma0, where sigma0 is the measurement uncertainty for zero true amount, is in the range of 3 to 5 depending on the true positive rate. Four times sigma0 rather than approximately two times sigma0, as in classical statistics, would seem a better choice for the decision level in these situations.

  15. Detection of Organic Compounds with Whole-Cell Bioluminescent Bioassays

    PubMed Central

    Xu, Tingting; Close, Dan; Smartt, Abby; Ripp, Steven

    2015-01-01

    Natural and manmade organic chemicals are widely deposited across a diverse range of ecosystems including air, surface water, groundwater, wastewater, soil, sediment, and marine environments. Some organic compounds, despite their industrial values, are toxic to living organisms and pose significant health risks to humans and wildlife. Detection and monitoring of these organic pollutants in environmental matrices therefore is of great interest and need for remediation and health risk assessment. Although these detections have traditionally been performed using analytical chemical approaches that offer highly sensitive and specific identification of target compounds, these methods require specialized equipment and trained operators, and fail to describe potential bioavailable effects on living organisms. Alternatively, the integration of bioluminescent systems into whole-cell bioreporters presents a new capacity for organic compound detection. These bioreporters are constructed by incorporating reporter genes into catabolic or signaling pathways that are present within living cells and emit a bioluminescent signal that can be detected upon exposure to target chemicals. Although relatively less specific compared to analytical methods, bioluminescent bioassays are more cost-effective, more rapid, can be scaled to higher throughput, and can be designed to report not only the presence but also the bioavailability of target substances. This chapter reviews available bacterial and eukaryotic whole-cell bioreporters for sensing organic pollutants and their applications in a variety of sample matrices. PMID:25084996

  16. Using enzyme bioassays as a rapid screen for metal toxicity

    USGS Publications Warehouse

    Choate, LaDonna M.; Ross, P.E.; Blumenstein, E. P.; Ranville, James F.

    2005-01-01

    Mine tailings piles and abandoned mine soils are often contaminated by a suite of toxic metals, which were released in the mining process. Traditionally, toxicity of such areas has been determined by numerous chemical methods including the Toxicity Characteristic Leachate Procedure (TCLP) and traditional toxicity tests using organisms such as the cladoceran Ceriodaphnia dubia. Such tests can be expensive and time-consuming. Enzymatic bioassays may provide an easier, less costly, and more time-effective toxicity screening procedure for mine tailings and abandoned mine soil leachates. This study evaluated the commercially available MetPLATE™ enzymatic toxicity assay test kit. The MetPLATE™ assay uses a modified strain of Escherichia coli bacteria as the test organism. Toxicity is defined by the activity of β-galactosidase enzyme which is monitored colorometrically with a 96-well spectrophotometer. The study used water samples collected from North Fork Clear Creek, a mining influenced water (MIW) located in Colorado. A great benefit to using the MetPLATE™ assay over the TCLP is that it shows actual toxicity of a sample by taking into account the bioavailability of the toxicants rather than simply measuring the metal concentration present. Benefits of the MetPLATE™ assay over the use of C. dubia include greatly reduced time for the testing process (∼2 hours), a more continuous variable due to a greater number of organisms present in each sample (100,000+), and the elimination of need to maintain a culture of organisms at all times.

  17. Development and characteristics of an adhesion bioassay for ectocarpoid algae.

    PubMed

    Evariste, Emmanuelle; Gachon, Claire M M; Callow, Maureen E; Callow, James A

    2012-01-01

    Species of filamentous brown algae in the family Ectocarpaceae are significant members of fouling communities. However, there are few systematic studies on the influence of surface physico-chemical properties on their adhesion. In the present paper the development of a novel, laboratory-based adhesion bioassay for ectocarpoid algae, at an appropriate scale for the screening of sets of experimental samples in well-replicated and controlled experiments is described. The assays are based on the colonization of surfaces from a starting inoculum consisting of multicellular filaments obtained by blending the cultured alga Ectocarpus crouaniorum. The adhesion strength of the biomass after 14 days growth was assessed by applying a hydrodynamic shear stress. Results from adhesion tests on a set of standard surfaces showed that E. crouaniorum adhered more weakly to the amphiphilic Intersleek® 900 than to the more hydrophobic Intersleek® 700 and Silastic® T2 coatings. Adhesion to hydrophilic glass was also weak. Similar results were obtained for other cultivated species of Ectocarpus but differed from those obtained with the related ectocarpoid species Hincksia secunda. The response of the ectocarpoid algae to the surfaces was also compared to that for the green alga, Ulva.

  18. Bioassays on Illinois waterway dredged material. Final report

    SciTech Connect

    Moore, D.W.; Gibson, A.B.; Dillon, T.M.

    1992-12-01

    Sediment from the Illinois Waterway navigation channel is hydraulically dredged by the US Army Engineer District, Rock Island, and placed in the nearshore environment via pipeline. Water returning to the river can have a high-suspended solids load approaching fluid mud consistency. There is a concern that this return water may exceed the State of Illinois water quality standards for ammonia and have adverse effects on aquatic life. To address these concerns, composite sediment samples and site water collected from selected sites in the Illinois Waterway were evaluated in toxicity tests. Acute (48-hr) toxicity tests were conducted with two species, Pimephales promelas (the fathead minnow) and Daphnia magna (a freshwater cladoceran). A chronic (21-day) toxicity test was also conducted using Daphnia magna. Animals were exposed separately to different concentrations of filtered and unfiltered elutriates prepared from Acute, Cadmium, Daphnia magna, Pimephales promela, Ammonia, Chronic, Elutriate, Sediment, Bioassay, Cladoceran, Fathead minnow. Illinois Waterway edged material. Total ammonia concentrations were measured in all tests and the un-ionized fraction was calculated by adjusting for temperature and pH. Tests were conducted at the US Army Engineer Waterways Experiment Station, Vicksburg, MS. In addition, as part of an interlaboratory effort, a 48-hr acute toxicity test with Pimephales pomelas fry was conducted concurrently by the Hygienic Laboratory of the University of Iowa, Des Moines, IA.

  19. Analyzing bioassay data using Bayesian methods -- A primer

    SciTech Connect

    Miller, G.; Inkret, W.C.; Schillaci, M.E.

    1997-10-16

    The classical statistics approach used in health physics for the interpretation of measurements is deficient in that it does not allow for the consideration of needle in a haystack effects, where events that are rare in a population are being detected. In fact, this is often the case in health physics measurements, and the false positive fraction is often very large using the prescriptions of classical statistics. Bayesian statistics provides an objective methodology to ensure acceptably small false positive fractions. The authors present the basic methodology and a heuristic discussion. Examples are given using numerically generated and real bioassay data (Tritium). Various analytical models are used to fit the prior probability distribution, in order to test the sensitivity to choice of model. Parametric studies show that the normalized Bayesian decision level k{sub {alpha}}-L{sub c}/{sigma}{sub 0}, where {sigma}{sub 0} is the measurement uncertainty for zero true amount, is usually in the range from 3 to 5 depending on the true positive rate. Four times {sigma}{sub 0} rather than approximately two times {sigma}{sub 0}, as in classical statistics, would often seem a better choice for the decision level.

  20. Sensitive bioassay for detection of biologically active ricin in food.

    PubMed

    Rasooly, Reuven; He, Xiaohua

    2012-05-01

    The potential use of ricin as an agent of biological warfare highlights the need to develop fast and effective methods to detect biologically active ricin. The current "gold standard" for ricin detection is an in vivo mouse bioassay; however, this method is not practical to test on a large number of samples and raises ethical concerns with regard to the use of experimental animals. In this work, we generated adenoviral vectors that express the green fluorescent protein gene and used the relative fluorescence units intensity inhibition by transduced cells for quantitative measurement of biologically active ricin. The detection limit of the assay was 200 pg/ml, which is over 500,000 times greater than the adult human lethal oral dose. The inhibition of fluorescence intensity between ricin treatment and control was higher in 72-h posttransduction Vero cells than 24-h human embryonic kidney cells. Therefore, to detect biologically active ricin in food matrices that might influence the assay, we used 72-h posttransduction Vero cells. This simple assay could be used for large-scale screening to detect biologically active ricin in food without added substrates or use of cell fixation methods.

  1. Bioassay-based risk assessment of complex mixtures

    SciTech Connect

    Donnelly, K.C.; Huebner, H.J.

    1996-12-31

    The baseline risk assessment often plays an integral role in various decision-making processes at Superfund sites. The present study reports on risk characterizations prepared for seven complex mixtures using biological and chemical analysis. Three of the samples (A, B, and C) were complex mixtures of polycyclic aromatic hydrocarbons (PAHs) extracted from coal tar; while four samples extracted from munitions-contaminated soil contained primarily nitroaromatic hydrocarbons. The chemical-based risk assessment ranked sample C as least toxic, while the risk associated with samples A and B was approximately equal. The microbial bioassay was in general agreement for the coal tar samples. The weighted activity of the coal tar extracts in Salmonella was 4,960 for sample C, and 162,000 and 206,000 for samples A and B, respectively. The bacterial mutagenicity of 2,4,6-trinitrotoluene contaminated soils exhibited an indirect correlation with chemical-based risk assessment. The aqueous extract of sample 004 induced 1,292 net revertants in Salmonella, while the estimated risk to ingestion and dermal adsorption was 2E-9. The data indicate that the chemical-based risk assessment accurately predicted the genotoxicity of the PAHs, while the accuracy of the risk assessment for munitions contaminated soils was limited due to the presence of metabolites of TNT degradation. The biological tests used in this research provide a valuable compliment to chemical analysis for characterizing the genotoxic risk of complex mixtures.

  2. Acetoclastic methanogenic activity measurement by a titration bioassay.

    PubMed

    Rozzi, Alberto; Castellazzi, Luca; Speece, Richard E

    2002-01-05

    A titration bioassay, designed to accurately determine the activity of acetoclastic methanogens, is described that also allows evaluation of inhibition due to potential toxicants on the active biomass. The instrument is made of a pH-stat connected to an anaerobic batch reactor. Acetate is blended and mixed with anaerobic sludge in the reactor where a 1:1 N2 and CO2 mixture is sparged at the beginning of each test. As the acetoclastic methanogens consume acetate, the pH increase, and the titration unit adds acetic acid and keeps the pH constant. The rate of titrant addition is directly proportional to the methanogenic activity. A very useful feature of the system is its potential to operate for long periods (days) at constant pH and substrate (acetate) concentration. The theoretical background and principle of operation are described as well as some of the practical problems encountered with the use of the instrument. Estimation of kinetic constants for an anaerobic culture according to the Michaelis-Menten model is presented. Examples of inhibition by inorganics (NaCl) and chlorinated solvents (chloroform) are also given.

  3. Target organs in chronic bioassays of 533 chemical carcinogens.

    PubMed Central

    Gold, L S; Slone, T H; Manley, N B; Bernstein, L

    1991-01-01

    A compendium of carcinogenesis bioassay results organized by target organ is presented for 533 chemicals that are carcinogenic in at least one species. This compendium is based primarily on experiments in rats or mice; results in hamsters, nonhuman primates, and dogs are also reported. The compendium can be used to identify chemicals that induce tumors at particular sites, and to determine whether target sites are the same for chemicals positive in more than one species. The Carcinogenic Potency Database (CPDB), which includes results of 3969 experiments, is used in the analysis. The published CPDB includes details on each test, and literature references. Chemical carcinogens are reported for 35 different target organs in rats or mice. More than 80% of the carcinogens in each of these species are positive in at least one of the 8 most frequent target sites: liver, lung, mammary gland, stomach, vascular system, kidney, hematopoietic system, and urinary bladder. An analysis is presented of how well one can predict the carcinogenic response in mice from results in rats, or vice versa. Among chemicals tested in both species, 76% of rat carcinogens are positive in mice, and 71% of mouse carcinogens are positive in rats. Prediction is less accurate to the same target site: 52% of rat carcinogens are positive in the same site in mice, and 48% of mouse carcinogens are positive in the same site in rats. The liver is the most frequent site in common between rats and mice. PMID:1773795

  4. USING BIOASSAYS TO EVALUATE THE PERFORMANCE OF EDC RISK MANAGEMENT METHODS

    EPA Science Inventory

    In Superfund risk management research, the performance of risk management techniques is typically evaluated by measuring "the concentrations of the chemicals of concern before and after risk management efforts. However, using bioassays and chemical data provides a more robust und...

  5. Comparison of solid-phase bioassays and ecoscores to evaluate the toxicity of contaminated soils.

    PubMed

    Lors, Christine; Ponge, Jean-François; Martínez Aldaya, Maite; Damidot, Denis

    2010-08-01

    Five bioassays (inhibition of lettuce germination and growth, earthworm mortality, inhibition of springtail population growth, avoidance by springtails) were compared, using four coke factory soils contaminated by PAHs and trace elements, before and after biotreatment. For each bioassay, several endpoints were combined in an 'ecoscore', a measure of test sensitivity. Ecoscores pooled over all tested bioassays revealed that most organisms were highly sensitive to the concentration of 3-ring PAHs. When four soils were combined, behavioural tests using the springtail Folsomia candida showed higher ecoscores, i.e. they were most sensitive to soil contamination. However, despite overall higher sensitivity of behavioural tests, which could be used for cheap and rapid assessment of soil toxicity, especially at low levels of contamination, some test endpoints were more sensitive than others, and this may differ from a soil to another, pointing to the need for a battery of bioassays when more itemized results are expected.

  6. IN SITU BIOASSAY CHAMBER FOR ASSESSMENT OF SEDIMENT TOXICITY AND BIOACCUMULATION USING BENTHIC INVERTEBRATES

    EPA Science Inventory

    In this study, we describe the construction of a simple, inexpensive bioassay chamber for testing sediment toxicity (survival and growth) and bioaccumulation under field conditions using the midge Chironomus tentans and the oligochaete Lumbriculus variegatus. The test chamber is ...

  7. Evaluation of toxicity of selected insecticides against thrips on cotton in laboratory bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adult vial technique (AVT) and spray table bioassays were conducted to evaluate toxicity of selected insecticides against immature and adult Western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). In AVT, technical insecticides comprising of organophosphates (d...

  8. Harmonia Axyridis Adults Avoid Catnip and Grapefruit-derived Terpenoids in Laboratory Bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We observed the avoidance behavior of the multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), when adults were exposed to volatiles derived from catnip oil and grapefruit seed. In replicated laboratory bioassays, beetles avoided contact with volatiles emanating f...

  9. Comparative susceptibility of bemisia tabaci to imidacloprid in field- and laboratory-based bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bemisia tabaci biotype B is a resistance-prone pest of protected and open agriculture. Systemic uptake bioassays used in resistance monitoring programs have provided important information on susceptibility to neonicotinoid insecticides, but have remained decoupled from field performance. Simultaneou...

  10. Biomonitoring of cyanotoxins in two tropical reservoirs by cladoceran toxicity bioassays.

    PubMed

    da S Ferrão-Filho, Aloysio; Soares, Maria Carolina S; de Freitas Magalhães, Valeria; Azevedo, Sandra M F O

    2009-02-01

    This study evaluates the potential for the use of cladocerans in biomonitoring of cyanobacterial toxins. Two zooplankton species (Daphnia gessneri and Moina micrura) were cultivated in the laboratory for use in acute (48 h) and chronic (10 days) bioassays. Water samples were collected from two reservoirs and diluted in mineral water at four concentrations. Survivorship in the acute bioassays was used to calculate LC50, and survivorship and fecundity in chronic bioassays were used to calculate the intrinsic population growth rate (r) and the EC50. Analysis of phytoplankton in the water samples from one reservoir revealed that cyanobacteria were the dominant group, represented by the genera Anabaena, Cylindrospermopsis, and Microcystis. Results of bioassays showed adverse effects including death, paralysis, and reduced population growth rate, generally proportional to the reservoir water concentration. These effects may be related to the presence of cyanobacteria toxins (microcystins or saxitoxins) in the water.

  11. A Standardized Lepidopteran Bioassay to Investigate the Bioactivity of Insecticidal Proteins Produced in Transgenic Crops.

    PubMed

    Graser, Gerson; Walters, Frederick S

    2016-01-01

    Insecticidal bioassays are the only reliable method to investigate the biological activity of an insecticidal protein and therefore provide an essential toolkit for the characterization and potency determination of these proteins. Here we present a standardized method for a lepidopteran larval bioassay, which is optimized to specifically estimate activity of insecticidal proteins produced in transgenic plants. The treatment can be either applied to the surface of the artificial diet, or blended into the diet.

  12. Considerations in Selecting Bioassay Organisms for Determining the Potential Environmental Impact of Dredged Material.

    DTIC Science & Technology

    1981-09-01

    using the water flea Daphnia magna , mayfly larvae Hexagenia limbata, and fatnead minnow Pimephales promelas. Thirteen of the sed- iments were collected...and Anderson 1 4 1 2 0 used larvae of the mayfly Hexagenia limbata, the water flea Daphnia magna , and the isopod Asellus communis in bioassays with...Various U.S. locations. Lee et al. 24 used the water flea Daphnia magna and the saltwater grass shrimp Palaemonetes pugio to conduct bioassays using the

  13. A simple, rapid bioassay for detecting effects of pollutants on bacteria

    SciTech Connect

    Bauer, N.J.; Seidler, R.J.; Knittel, M.D.

    1981-12-01

    A screening bioassay needs to be rapid, and sensitive. The bioassay is described which is accurate, inexpensive, and which utilizes bacteria as the toxicity predictor. The basis of the test involves measuring the kinetics of dissolved oxygen depletion by a mixed microbial population following exposure to a pollutant and allows results to be obtained in as little as 40 min. Pollutants tested were cadmium, copper, nickel, sulfate, diuron, pentachlorophenol, atrazine, tricholoracetic acid, dimethylformamide, and diazinon. (JMT)

  14. Application of root bioassays to detect nutrient deficiencies in fast-growing trees and agroforestry crops

    SciTech Connect

    Harrison, A.F.; Dighton, J.; Jones, H.E.

    1992-12-31

    A new method for the detection of nutrient deficiencies is outlined and recommended as an alternative to conventional soil and foliar analyses. Bioassays are conducted to measure the uptake and supply of the macronutrients. Examples are quoted of the successful use of this technique with Eucalyptus and Sitka spruce. The bioassays have been shown to give equally good results with a range of tree and ground crops.

  15. Annotated Bibliography of Bioassays Related to Sediment Toxicity Testing in Washington State

    DTIC Science & Technology

    1990-10-01

    REVIEWS GENERAL Anderson, B. S ., J. W. Hunt, M. Martin, S . L. Turpen and F. H. Palmer. 1988. Marine bioassay project, third report. Protocol development ...Office of Research and Development , U. S . Environmental Protection Agency, Corvallis, OR. 60 pp. This is an acute bioassay manual designed by an EPA...test species are: 1. Purple sea urchin, Strongylocentrotus purpuratus 2. Green sea urchin, S . droebachiensis 3. Sand dollai, Dendraster excentricus

  16. Identification of sources of plant resistance to Diaprepes abbreviatus (Coleoptera: Curculionidae) by three bioassays.

    PubMed

    Lapointe, S L; Shapiro, J P; Bowman, K D

    1999-08-01

    Host plant resistance to the root weevil Diaprepes abbreviatus (L.) was assessed for 3 citrus rootstock cultivars, 5 promising hybrid rootstocks, and 3 citroid fruit trees using 3 bioassay methods: a pot bioassay with 1-yr seedlings; a new, 21-cm plastic cell bioassay with 5-mo seedlings; and a diet incorporation bioassay. The plastic cell bioassay is a more rapid screening method and is capable of evaluating a larger number of entries in a shorter period compared with current methods. The 3 bioassays yielded similar results. Larval growth was inhibited by 2 of the remote citroid fruit trees, Murraya koenigii (L.) Sprengel and Glycosmis pentaphylla (Retzius) Correa, compared with growth on commercial rootstock cultivars. Specifically, larvae allowed to feed on roots of M. koenigii or G. pentaphylla gained less weight compared with larvae fed on the commercial rootstock cultivar 'Swingle' [Citrus paradisi Macfayden x Poncirus trifoliata (L.) Rafinesque-Schmaltz]. The resistance of G. pentaphylla confirms previous reports. M. koenigii is a new source of resistance to D. abbreviatus.

  17. An overview of the PubChem BioAssay resource.

    PubMed

    Wang, Yanli; Bolton, Evan; Dracheva, Svetlana; Karapetyan, Karen; Shoemaker, Benjamin A; Suzek, Tugba O; Wang, Jiyao; Xiao, Jewen; Zhang, Jian; Bryant, Stephen H

    2010-01-01

    The PubChem BioAssay database (http://pubchem.ncbi.nlm.nih.gov) is a public repository for biological activities of small molecules and small interfering RNAs (siRNAs) hosted by the US National Institutes of Health (NIH). It archives experimental descriptions of assays and biological test results and makes the information freely accessible to the public. A PubChem BioAssay data entry includes an assay description, a summary and detailed test results. Each assay record is linked to the molecular target, whenever possible, and is cross-referenced to other National Center for Biotechnology Information (NCBI) database records. 'Related BioAssays' are identified by examining the assay target relationship and activity profile of commonly tested compounds. A key goal of PubChem BioAssay is to make the biological activity information easily accessible through the NCBI information retrieval system-Entrez, and various web-based PubChem services. An integrated suite of data analysis tools are available to optimize the utility of the chemical structure and biological activity information within PubChem, enabling researchers to aggregate, compare and analyze biological test results contributed by multiple organizations. In this work, we describe the PubChem BioAssay database, including data model, bioassay deposition and utilities that PubChem provides for searching, downloading and analyzing the biological activity information contained therein.

  18. User-friendly 3D bioassays with cell-containing hydrogel modules: narrowing the gap between microfluidic bioassays and clinical end-users' needs.

    PubMed

    Lee, Do-Hyun; Bae, Chae Yun; Kwon, Seyong; Park, Je-Kyun

    2015-06-07

    Cell-containing hydrogel modules as cell-hydrogel microunits for creating a physiologically relevant 3D in vivo-like microenvironment with multiple cell types and unique extracellular matrix (ECM) compositions facilitate long-term cell maintenance and bioassays. To date, there have been many important advances in microfluidic bioassays, which incorporate hydrogel scaffolds into surface-accessible microchambers, driven by the strong demand for the application of spatiotemporally defined biochemical stimuli to construct in vivo-like conditions and perform real-time imaging of cell-matrix interactions. In keeping with the trend of fostering collaborations among biologists, clinicians, and microfluidic engineers, it is essential to create a simpler approach for coupling cell-containing hydrogel modules and an automated bioassay platform in a user-friendly format. In this article, we review recent progress in hydrogel-incorporated microfluidics for long-term cell maintenance and discuss some of the simpler and user-friendly 3D bioassay techniques combined with cell-containing hydrogel modules that can be applied to mutually beneficial collaborations with non-engineers. We anticipate that this modular and user-friendly format interfaced with existing laboratory infrastructure will help address several clinical questions in ways that extend well beyond the current 2D cell-culture systems.

  19. Advances in Surface-Enhanced Fluorescence

    PubMed Central

    Lakowicz, Joseph R.; Geddes, Chris D.; Gryczynski, Ignacy; Malicka, Joanna; Gryczynski, Zygmunt; Aslan, Kadir; Lukomska, Joanna; Matveeva, Evgenia; Zhang, Jian; Badugu, Ramachandram; Huang, Jun

    2009-01-01

    We report recent achievements in metal-enhanced fluorescence from our laboratory. Several fluorophore systems have been studied on metal particle-coated surfaces and in colloid suspensions. In particular, we describe a distance dependent enhancement on silver island films (SIFs), release of self-quenching of fluorescence near silver particles, and the applications of fluorescence enhancement near metalized surfaces to bioassays. We discuss a number of methods for various shaped silver particle deposition on surfaces. PMID:15617385

  20. Benchmarking organic micropollutants in wastewater, recycled water and drinking water with in vitro bioassays.

    PubMed

    Escher, Beate I; Allinson, Mayumi; Altenburger, Rolf; Bain, Peter A; Balaguer, Patrick; Busch, Wibke; Crago, Jordan; Denslow, Nancy D; Dopp, Elke; Hilscherova, Klara; Humpage, Andrew R; Kumar, Anu; Grimaldi, Marina; Jayasinghe, B Sumith; Jarosova, Barbora; Jia, Ai; Makarov, Sergei; Maruya, Keith A; Medvedev, Alex; Mehinto, Alvine C; Mendez, Jamie E; Poulsen, Anita; Prochazka, Erik; Richard, Jessica; Schifferli, Andrea; Schlenk, Daniel; Scholz, Stefan; Shiraishi, Fujio; Snyder, Shane; Su, Guanyong; Tang, Janet Y M; van der Burg, Bart; van der Linden, Sander C; Werner, Inge; Westerheide, Sandy D; Wong, Chris K C; Yang, Min; Yeung, Bonnie H Y; Zhang, Xiaowei; Leusch, Frederic D L

    2014-01-01

    Thousands of organic micropollutants and their transformation products occur in water. Although often present at low concentrations, individual compounds contribute to mixture effects. Cell-based bioassays that target health-relevant biological endpoints may therefore complement chemical analysis for water quality assessment. The objective of this study was to evaluate cell-based bioassays for their suitability to benchmark water quality and to assess efficacy of water treatment processes. The selected bioassays cover relevant steps in the toxicity pathways including induction of xenobiotic metabolism, specific and reactive modes of toxic action, activation of adaptive stress response pathways and system responses. Twenty laboratories applied 103 unique in vitro bioassays to a common set of 10 water samples collected in Australia, including wastewater treatment plant effluent, two types of recycled water (reverse osmosis and ozonation/activated carbon filtration), stormwater, surface water, and drinking water. Sixty-five bioassays (63%) showed positive results in at least one sample, typically in wastewater treatment plant effluent, and only five (5%) were positive in the control (ultrapure water). Each water type had a characteristic bioanalytical profile with particular groups of toxicity pathways either consistently responsive or not responsive across test systems. The most responsive health-relevant endpoints were related to xenobiotic metabolism (pregnane X and aryl hydrocarbon receptors), hormone-mediated modes of action (mainly related to the estrogen, glucocorticoid, and antiandrogen activities), reactive modes of action (genotoxicity) and adaptive stress response pathway (oxidative stress response). This study has demonstrated that selected cell-based bioassays are suitable to benchmark water quality and it is recommended to use a purpose-tailored panel of bioassays for routine monitoring.

  1. Reading disc-based bioassays with standard computer drives.

    PubMed

    Yu, Hua-Zhong; Li, Yunchao; Ou, Lily M-L

    2013-02-19

    -based bioassays quantitatively. In this Account, we first provide a brief introduction to CD-related materials chemistry and microfluidics research. Then we describe the mild chemistry developed in our laboratory for the preparation of computer-readable biomolecular screening assays: photochemical activation of the polycarbonate (PC) disc surface and immobilization and delivery of probe and target biomolecules. We thoroughly discuss the analysis of the molecular recognition events: researchers can "read" these devices quantitatively with an unmodified optical drive of any personal computer. Finally, and critically, we illustrate our digitized molecular diagnosis approach with three trial systems: DNA hybridization, antibody-antigen binding, and ultrasensitive lead detection with a DNAzyme assay. These examples demonstrate the broad potential of this new analytical/diagnostic tool for medical screening, on-site food/water safety testing, and remote environmental monitoring.

  2. Susceptibility of Bagrada hilaris (Hemiptera: Pentatomidae) to Insecticides in Laboratory and Greenhouse Bioassays.

    PubMed

    Palumbo, John C; Prabhaker, Nilima; Reed, Darcy A; Perring, Thomas M; Castle, Steven J; Huang, Ta-I

    2015-04-01

    Field-collected nymphs and adults of Bagrada hilaris (Burmeister) (Hemiptera: Penatatomidae) from three locations were evaluated for susceptibility to insecticides representing 10 classes of insecticide chemistry. Although relative susceptibilities differed between leaf-spray and leaf-dip Petri dish bioassays, consistently low LC50 values were determined for chlorpyrifos, bifenthrin, and lambda-cyhalothrin. Fenpropathrin and methomyl had intermediate values. Susceptibility to dinotefuran varied depending on the bioassay, possibly owing to leaf substrates used in the two bioassays. In soil systemic bioassays, the LC50 value of dinotefuran was significantly greater than that of two other neonicotinoids, imidacloprid and thiamethoxam, and the anthranilic diamide, cyantraniliprole. Mortality and feeding damage of B. hilaris and plant growth on insecticide-treated plants in greenhouse trials were consistent with the laboratory bioassays; the best results were seen with bifenthrin, methomyl, and chlorpyrifos. Mortality to the neonicotinoids was not evident; however, feeding damage and plant growth responses on dinotefuran-treated plants damage were similar to the noninfested control. This highlights the apparent antifeedant properties of dinotefuran that may have prevented adults from injuring broccoli plants after exposure to foliar spray residues. Data presented serve as baseline susceptibilities that can be used to monitor for resistance development in field populations of B. hilaris.

  3. Selecting a sensitive battery of bioassays to detect toxic effects of metals in effluents.

    PubMed

    de Paiva Magalhães, Danielly; da Costa Marques, Mônica Regina; Fernandes Baptista, Darcilio; Forsin Buss, Daniel

    2014-09-07

    The use of bioassay batteries is necessary to evaluate toxic effects at various biological levels. The selection of bioassays without prior testing and determination of the most sensitive/suitable groups for each impact may allow the discharge of effluents that pose a threat to the environment. The present study tested and selected a battery of sensitive ecotoxicological bioassays for detecting toxic effects of metals. The sensitivities of six organisms were evaluated (algae Pseudokirchneriella subcapitata and Chlorella vulgaris, Cladocera Daphnia similis and Ceriodaphnia dubia, and fish Poecilia reticulata and Danio rerio) after exposure to 10 individual metal species deemed toxic to the aquatic environment (Ag(+), Cd(2+), Cu(+), Cu(2+), Cr(3+), Cr(6+), Pb(2+), Ni(2+), Zn(2+), and Hg(2+)) and to real (steel-mill) and laboratory simulated effluents. In the bioassays, fish were the least sensitive; D. rerio showed no sensitivity to any of the effluents tested. P. subcapitata was a good bioindicator of Cr(3+) toxicity, and D. similis was the most sensitive organism to Hg(2+); but the toxic effect of effluents with higher levels of Hg(2+) was better detected by C. dubia. The most sensitive battery of bioassays to detect low concentrations of dissolved metals in effluents was the 72-h chronic test with C. vulgaris and the 48-h acute test with C. dubia.

  4. Comparison of five in vitro bioassays to measure estrogenic activity in environmental waters.

    PubMed

    Leusch, Frederic D L; de Jager, Christiaan; Levi, Yves; Lim, Richard; Puijker, Leo; Sacher, Frank; Tremblay, Louis A; Wilson, Vickie S; Chapman, Heather F

    2010-05-15

    Bioassays are well established in the pharmaceutical industry and single compound analysis, but there is still uncertainty about their usefulness in environmental monitoring. We compared the responses of five bioassays designed to measure estrogenic activity (the yeast estrogen screen, ER-CALUX, MELN, T47D-KBluc, and E-SCREEN assays) and chemical analysis on extracts from four different water sources (groundwater, raw sewage, treated sewage, and river water). All five bioassays displayed similar trends and there was good agreement with analytical chemistry results. The data from the ER-CALUX and E-SCREEN bioassays were robust and predictable, and well-correlated with predictions from chemical analysis. The T47D-KBluc appeared likewise promising, but with a more limited sample size it was less compelling. The YES assay was less sensitive than the other assays by an order of magnitude, which resulted in a larger number of nondetects. The MELN assay was less predictable, although the possibility that this was due to laboratory-specific difficulties cannot be discounted. With standardized bioassay data analysis and consistency of operating protocols, bioanalytical tools are a promising advance in the development of a tiered approach to environmental water quality monitoring.

  5. Evaluation of acute bioassays for assessing toxicity of polychlorinated biphenyl-contaminated soils

    SciTech Connect

    Hose, J.E.; Barlow, L.A.; Bent, S.; Elseewi, A.A.; Cliath, M.; Resketo, M.; Doyle, C.

    1986-03-01

    Proposed State of California regulations use fish toxicity information as one criterion in municipal or industrial waste hazard evaluation. Static 96-hr bioassays were performed using fathead minnows (Pimephales promelas), blacksmith (Chromis punctipinnis), and glass shrimp (Palaemonetes kadiakensis) exposed to soil experimentally contaminated with up to 500 ppm polychlorinated biphenyl (PCB) capacitor fluid added at a concentration of 500 mg liter-1. Other bioassays were conducted with a 6-day mixing period prior to the bioassay or with acetone added to solubilize the PCBs. No mortality attributable to PCB toxicity was observed in definitive bioassays using the two fish and one invertebrate species. PCB levels leached from soil containing 500 ppm Aroclor 1242 ranged from less than 0.6 to 3.4 ppb in freshwater tests to 3.5 ppb in seawater bioassays. Using these data as the basis for waste classification, soils contaminated with up to 500 ppb PCBs during capacitor spills would be designated nonhazardous. PCBs are known to be environmentally persistent and to bioaccumulate. Acute toxicity tests, therefore, do not adequately evaluate the general toxicity of PCB-contaminated soils. Hazardous waste regulations for hydrophobic compounds such as PCBs should instead be based upon chronic toxicity data and should also consider bioaccumulation potential.

  6. Evaluation of acute bioassays for assessing toxicity of polychlorinated biphenyl-contaminated soils.

    PubMed

    Hose, J E; Barlow, L A; Bent, S; Elseewi, A A; Cliath, M; Resketo, M; Doyle, C

    1986-03-01

    Proposed State of California regulations use fish toxicity information as one criterion in municipal or industrial waste hazard evaluation. Static 96-hr bioassays were performed using fathead minnows (Pimephales promelas), blacksmith (Chromis punctipinnis), and glass shrimp (Palaemonetes kadiakensis) exposed to soil experimentally contaminated with up to 500 ppm polychlorinated biphenyl (PCB) capacitor fluid added at a concentration of 500 mg liter-1. Other bioassays were conducted with a 6-day mixing period prior to the bioassay or with acetone added to solubilize the PCBs. No mortality attributable to PCB toxicity was observed in definitive bioassays using the two fish and one invertebrate species. PCB levels leached from soil containing 500 ppm Aroclor 1242 ranged from less than 0.6 to 3.4 ppb in freshwater tests to 3.5 ppb in seawater bioassays. Using these data as the basis for waste classification, soils contaminated with up to 500 ppb PCBs during capacitor spills would be designated nonhazardous. PCBs are known to be environmentally persistent and to bioaccumulate. Acute toxicity tests, therefore, do not adequately evaluate the general toxicity of PCB-contaminated soils. Hazardous waste regulations for hydrophobic compounds such as PCBs should instead be based upon chronic toxicity data and should also consider bioaccumulation potential.

  7. Characterization of chemical waste site contamination and its extent using bioassays

    SciTech Connect

    Thomas, J.M.; Callahan, C.A.; Cline, J.F.; Greene, J.C.; McShane, M.C.; Miller, W.E.; Peterson, S.A.; Simpson, J.C.; Skalski, J.R.

    1984-12-01

    Bioassays were used in a three-phase research project to assess the comparative sensitivity of test organisms to known chemicals, determine if the chemical components in field soil and water samples containing unknown contaminants could be inferred from our laboratory studies using known chemicals, and to investigate kriging (a relatively new statistical mapping technique) and bioassays as methods to define the areal extent of chemical contamination. The algal assay generally was most sensitive to samples of pure chemicals, soil elutriates and water from eight sites with known chemical contamination. Bioassays of nine samples of unknown chemical composition from the Rocky Mountain Arsenal (RMA) site showed that a lettuce seed soil contact phytoassay was most sensitive. In general, our bioassays can be used to broadly identify toxic components of contaminated soil. Nearly pure compounds of insecticides and herbicides were less toxic in the sensitive bioassays than were the counterpart commercial formulations. This finding indicates that chemical analysis alone may fail to correctly rate the severity of environmental toxicity. Finally, we used the lettuce seed phytoassay and kriging techniques in a field study at RMA to demonstrate the feasibility of mapping contamination to aid in cleanup decisions. 25 references, 9 figures, 9 tables.

  8. Studies on the bioassayable growth hormone-like activity of plasma

    NASA Technical Reports Server (NTRS)

    Ellis, S.; Vodian, M. A.; Grindeland, R. E.

    1978-01-01

    Evidence supporting the existence of bioassayable growth hormone-like activity in blood plasma distinct from the growth hormone measurable by radioimmunoassay and from somatomedin is presented. Tibial assays of the growth-hormone-like activity of injected, concentrated normal human and rat plasma in hypophysectomized rats reveal 200- and 50-fold activity excesses, respectively, with respect to the amount of growth hormone detected by radioimmunoassay. The origin of this bioassayable plasma hormone has been localized to the region of the pituitary, the origin of growth hormone, a distribution not followed by somatomedin C. Purification of the bioassayable agent indicates that is has a molecular weight of between 60,000 and 80,000, in contrast to that of growth hormone (20,000), and that the bioassayable activity is distinct from that of somatomedin C. Growth hormone-like activity detected in Cohn fraction IV as well as plasma activity, are found to be collectable on Dowex 50 resin, in contrast to somatomedin C and nonsuppressible insulin-like activity. The formation of bioassayable growth hormone-activity agents from radioimmunoassayable growth hormone and directly in the pituitary is suggested.

  9. Getting ready for the manned mission to Mars: bioassays for space research

    NASA Astrophysics Data System (ADS)

    Baumstark-Khan, Christa; Hellweg, Christine E.; Arenz, Andrea; Meier, Matthias M.; Horneck, Gerda

    2004-06-01

    Harmful environmental factors - namely ionizing radiation - will continue to influence future manned space missions. The Cellular Biodiagnostic group at the German Aerospace Center (DLR) develops cellular monitoring systems, which include bacterial and mammalian cell systems capable of recognizing DNA damage as a consequence of the presence of genotoxic conditions. Such bioassay or biosensor systems will complement the physical detector systems used in space, insofar as they yield intrinsically biologically weighted measures of cellular responses. Furthermore, synergistic mutagenic and cancerogenic impacts of the radiation environment together with other potentially genotoxic constituents of the space habitat can be quantified using such systems, whose signals are especially relevant for the molecular damage to the DNA or the chromosomes. The experiment Cellular Responses to Radiation in Space (CERASP) has been selected by NASA to be performed on the International Space Station. It will supply basic information on the cellular response to radiation applied in microgravity. One of the biological end-points under investigation will be survival reflected by radiation-dependent reduction of constitutive expression of the enhanced variant of green fluorescent protein (EGFP), originally isolated from the bioluminescent jellyfish Aequorea victoria. A second end-point will be gene activation by space flight conditions in mammalian cells, based on fluorescent promoter reporter systems using the destabilized EGFP variant (d2EGFP). The promoter element to be investigated will reflect the activity of the NF-kappaB stress response pathway as an anti-apoptotic radiation response. DNA damage will be measured by fluorescent analysis of DNA unwinding (FADU). The systems have worked properly for terrestrial applications during the first experiments. Experiments using accelerated particles produced at the French heavy ion accelerator GANIL have given insights into cellular mechanisms

  10. Facile synthesis of methotrexate intercalated layered double hydroxides: particle control, structure and bioassay explore.

    PubMed

    Tian, De-Ying; Liu, Zhen-Lei; Li, Shu-Ping; Li, Xiao-Dong

    2014-12-01

    To study the influence of particle size on drug efficacy and other properties, a series of methotrexate intercalated layered double hydroxides (MTX/LDHs) were synthesized through the traditional coprecipitation method, using a mixture of water and polyethylene glycol (PEG-400) as the solvent. To adjust the particle size of MTX/LDHs, the dropping way, the volume ratio of water to PEG-400 and different hydrothermal treatment time changed accordingly, and the results indicate that the particle size can be controlled between 90 and 140 nm. Elemental C/H/N and inductive coupled plasma (ICP) analysis indicated that different synthesis conditions almost have no effect on the compositions of the nanohybrids. X-ray diffraction (XRD) patterns manifested the successful intercalation of MTX anions into the LDH interlayers, and it's also found out that different volume ratios of water to PEG-400 and variable dropping way can affect the crystallinity of the final samples, i.e., the volume ratio of 3:1 and pH decreasing are proved to be optimum conditions. Furthermore, both antiparallel monolayer and bilayers adopting different orientations are suggested for four samples from XRD results. Fourier transform infrared spectroscopy (FTIR) investigations proved the coexistence of CO3(2-) and MTX anions in the interlayer of the nanohybrids. MTX/LDH particles exhibited hexagonal platelet morphology with round corner and different dropping ways can affect the morphology greatly. Moreover, a DSC study indicated that longer time treatment can weaken the bond between the MTX anions and LDH layers. The kinetic release profiles told us that larger MTX/LDH particles have enhanced the ability of LDH layers to protect interlayer molecules. At last, the bioassay study indicated that the nanohybrids with larger diameters have higher tumor suppression efficiency.

  11. A medium-term rat liver bioassay for rapid in vivo detection of carcinogenic potential of chemicals.

    PubMed

    Ito, Nobuyuki; Tamano, Seiko; Shirai, Tomoyuki

    2003-01-01

    A reliable medium-term bioassay system for rapid detection of carcinogenic potential of chemicals in the human environment has been developed. The 8-week-protocol consists of 2 stages; male F344 rats are given a single intraperitoneal injection of diethylnitrosamine (200 mg/kg) for initiation of liver carcinogenesis, followed by a 6-week test chemical treatment starting 2 weeks thereafter. Test chemicals are usually given in the diet or the drinking water and in the 2nd week of test chemical treatment, all rats are subjected to two-thirds partial hepatectomy in order to induce regenerative cell replication. The end-point marker is the glutathione S-transferase placental form (GST-P)-positive hepatic focus, the numbers and sizes of which are analyzed using an image-analyzer and expressed as values per unit liver section (1 cm2). When the yield of GST-P-positive foci is significantly enhanced (P<0.05) over the control value, a chemical is judged to possess carcinogenic or promotion potential for the liver. Among 313 chemicals already tested in this system in our laboratory, 30/31 (97%) mutagenic hepatocarcinogens and 29/33 (88%) non-mutagenic hepatocarcinogens gave positive results. Ten out of 43 (23%) agents known to be carcinogenic in organs other than the liver were also positive. It is particularly important that only one of 48 non-carcinogens gave a very weak positive result, so that the system has a very low false-positivity rate. It is now well documented that the assay system is highly effective for detecting hepatocarcinogens, bridging the gap between traditional long-term carcinogenicity tests and short-term screening assays. At the Fourth International Conference on Harmonization, our medium-term liver bioassay based on an initiation and promotion protocol was recommended in the guidelines as an acceptable alternative to the long-term rodent carcinogenicity test.

  12. Optimal fractionation and bioassay plans for isolation of synergistic chemicals: The subtractive-combination method.

    PubMed

    Byers, J A

    1992-09-01

    Studies of chemical ecology of an organism are founded on the isolation and identification of a semiochemical, often comprised of two or more synergistic compounds (each Synergist alone has little activity, but presented together they are bioactive). Chromatographie fractionation and bioassay methods of binary splitting, additive combination, and subtractive combination are compared for efficiency in isolating synergists. Formulas are derived for the latter two methods that calculate the expected number of bioassay tests required for isolation of from two to five synergists from biological extracts with any number of compounds, depending on the number of initial (major) Chromatographic fractions. A computer program based on the formulas demonstrates the superiority of the subtractive-combination method. Simulations with the program were used to determine the optimal number of initial fractions for the additive- and subtractive-combination methods when isolating two to five synergists from extracts of from 25 to 1200 compounds. Methods of bioassay, isolation, identification, and field testing of semiochemicals are discussed.

  13. Toxicity screening of diclofenac, propranolol, sertraline and simvastatin using Danio rerio and Paracentrotus lividus embryo bioassays.

    PubMed

    Ribeiro, Sílvia; Torres, Tiago; Martins, Rosário; Santos, Miguel M

    2015-04-01

    Early life-stage bioassays have been used as an alternative to short-term adult toxicity tests since they are cost-effective. A single couple can produce hundreds or thousands of embryos and hence can be used as a simple high-throughput approach in toxicity studies. In the present study, zebrafish and sea urchin embryo bioassays were used to test the toxicity of four pharmaceuticals belonging to different therapeutic classes: diclofenac, propranolol, simvastatin and sertraline. Simvastatin was the most toxic tested compound for zebrafish embryo, followed by diclofenac. Sertraline was the most toxic drug to sea urchin embryos, inducing development abnormalities at the ng/L range. Overall, our results highlight the potential of sea urchin embryo bioassay as a promising and sensitive approach for the high-throughput methods to test the toxicity of new chemicals, including pharmaceuticals, and identify several drugs that should go through more detailed toxicity assays.

  14. Bioassay, isolation and studies on the mechanism of action of neurite extension factor

    NASA Technical Reports Server (NTRS)

    Kligman, D.

    1984-01-01

    The identification and purification of molecules active in promoting neurite outgrowth requires a sensitive reproducible bioassay. A quantitative bioassay was utilized to purify a neurite extension factor (NEF) based on counting the number of phase bright neurons with processes at least equal to one cell body diameter after 20 hrs. in culture is defined, serum free medium. Using a combination of heat treatment DEAE cellulose chromatography and gel filtration, an acidic protein of M sub r = 75,000 was highly purified. Upon reduction, it yields subunits of M sub r = 37,000. Purified fractions are active half maximally at 100 ng/ml in inducing neurite outgrowth in this bioassay. Currently, monoclonal antibodies to NEF are being produced. Female Balb C mice were immunized with the antigen and fusions with mouse myeloma cells will be performed to yield hybridoma cells.

  15. Strategies for Transferring Mixtures of Organic Contaminants from Aquatic Environments into Bioassays.

    PubMed

    Jahnke, Annika; Mayer, Philipp; Schäfer, Sabine; Witt, Gesine; Haase, Nora; Escher, Beate I

    2016-06-07

    Mixtures of organic contaminants are ubiquitous in the environment. Depending on their persistence and physicochemical properties, individual chemicals that make up the mixture partition and distribute within the environment and might then jointly elicit toxicological effects. For the assessment and monitoring of such mixtures, a variety of cell-based in vitro and low-complexity in vivo bioassays based on algae, daphnids or fish embryos are available. A very important and sometimes unrecognized challenge is how to combine sampling, extraction and dosing to transfer the mixtures from the environment into bioassays, while conserving (or re-establishing) their chemical composition at adjustable levels for concentration-effect assessment. This article outlines various strategies for quantifiable transfer from environmental samples including water, sediment, and biota into bioassays using total extraction or polymer-based passive sampling combined with either solvent spiking or passive dosing.

  16. Bioassay for estimating the biogenic methane-generating potential of coal samples

    USGS Publications Warehouse

    Jones, E.J.P.; Voytek, M.A.; Warwick, P.D.; Corum, M.D.; Cohn, A.; Bunnell, J.E.; Clark, A.C.; Orem, W.H.

    2008-01-01

    Generation of secondary biogenic methane in coal beds is likely controlled by a combination of factors such as the bioavailability of coal carbon, the presence of a microbial community to convert coal carbon to methane, and an environment supporting microbial growth and methanogenesis. A set of treatments and controls was developed to bioassay the bioavailability of coal for conversion to methane under defined laboratory conditions. Treatments included adding a well-characterized consortium of bacteria and methanogens (enriched from modern wetland sediments) and providing conditions to support endemic microbial activity. The contribution of desorbed methane in the bioassays was determined in treatments with bromoethane sulfonic acid, an inhibitor of microbial methanogenesis. The bioassay compared 16 subbituminous coal samples collected from beds in Texas (TX), Wyoming (WY), and Alaska (AK), and two bituminous coal samples from Pennsylvania (PA). New biogenic methane was observed in several samples of subbituminous coal with the microbial consortium added, but endemic activity was less commonly observed. The highest methane generation [80????mol methane/g coal (56??scf/ton or 1.75??cm3/g)] was from a south TX coal sample that was collected from a non-gas-producing well. Subbituminous coals from the Powder River Basin, WY and North Slope Borough, AK contained more sorbed (original) methane than the TX coal sample and generated 0-23????mol/g (up to 16??scf/ton or 0.5??cm3/g) new biogenic methane in the bioassay. Standard indicators of thermal maturity such as burial depth, nitrogen content, and calorific value did not explain differences in biogenic methane among subbituminous coal samples. No original methane was observed in two bituminous samples from PA, nor was any new methane generated in bioassays of these samples. The bioassay offers a new tool for assessing the potential of coal for biogenic methane generation, and provides a platform for studying the

  17. In vitro bioassays to evaluate complex chemical mixtures in recycled water

    PubMed Central

    Jia, Ai; Escher, Beate I.; Leusch, Frederic D.L.; Tang, Janet Y.M.; Prochazka, Erik; Dong, Bingfeng; Snyder, Erin M.; Snyder, Shane A.

    2016-01-01

    With burgeoning population and diminishing availability of freshwater resources, the world continues to expand the use of alternative water resources for drinking, and the quality of these sources has been a great concern for the public as well as public health professionals. In vitro bioassays are increasingly being used to enable rapid, relatively inexpensive toxicity screening that can be used in conjunction with analytical chemistry data to evaluate water quality and the effectiveness of water treatment. In this study, a comprehensive bioassay battery consisting of 36 bioassays covering 18 biological endpoints was applied to screen the bioactivity of waters of varying qualities with parallel treatments. Samples include wastewater effluent, ultraviolet light (UV) and/or ozone advanced oxidation processed (AOP) recycled water, and infiltrated recycled groundwater. Based on assay sensitivity and detection frequency in the samples, several endpoints were highlighted in the battery, including assays for genotoxicity, mutagenicity, estrogenic activity, glucocorticoid activity, aryl hydrocarbon receptor activity, oxidative stress response, and cytotoxicity. Attenuation of bioactivity was found to be dependent on the treatment process and bioassay endpoint. For instance, ozone technology significantly removed oxidative stress activity, while UV based technologies were most efficient for the attenuation of glucocorticoid activity. Chlorination partially attenuated genotoxicity and greatly decreased herbicidal activity, while groundwater infiltration efficiently attenuated most of the evaluated bioactivity with the exception of genotoxicity. In some cases, bioactivity (e.g., mutagenicity, genotoxicity, and arylhydrocarbon receptor) increased following water treatment, indicating that transformation products of water treatment may be a concern. Furthermore, several types of bioassays with the same endpoint were compared in this study, which could help guide the selection

  18. In vitro bioassays to evaluate complex chemical mixtures in recycled water.

    PubMed

    Jia, Ai; Escher, Beate I; Leusch, Frederic D L; Tang, Janet Y M; Prochazka, Erik; Dong, Bingfeng; Snyder, Erin M; Snyder, Shane A

    2015-09-01

    With burgeoning population and diminishing availability of freshwater resources, the world continues to expand the use of alternative water resources for drinking, and the quality of these sources has been a great concern for the public as well as public health professionals. In vitro bioassays are increasingly being used to enable rapid, relatively inexpensive toxicity screening that can be used in conjunction with analytical chemistry data to evaluate water quality and the effectiveness of water treatment. In this study, a comprehensive bioassay battery consisting of 36 bioassays covering 18 biological endpoints was applied to screen the bioactivity of waters of varying qualities with parallel treatments. Samples include wastewater effluent, ultraviolet light (UV) and/or ozone advanced oxidation processed (AOP) recycled water, and infiltrated recycled groundwater. Based on assay sensitivity and detection frequency in the samples, several endpoints were highlighted in the battery, including assays for genotoxicity, mutagenicity, estrogenic activity, glucocorticoid activity, arylhydrocarbon receptor activity, oxidative stress response, and cytotoxicity. Attenuation of bioactivity was found to be dependent on the treatment process and bioassay endpoint. For instance, ozone technology significantly removed oxidative stress activity, while UV based technologies were most efficient for the attenuation of glucocorticoid activity. Chlorination partially attenuated genotoxicity and greatly decreased herbicidal activity, while groundwater infiltration efficiently attenuated most of the evaluated bioactivity with the exception of genotoxicity. In some cases, bioactivity (e.g., mutagenicity, genotoxicity, and arylhydrocarbon receptor) increased following water treatment, indicating that transformation products of water treatment may be a concern. Furthermore, several types of bioassays with the same endpoint were compared in this study, which could help guide the selection

  19. Genotoxicity of soil from farmland irrigated with wastewater using three plant bioassays.

    PubMed

    Cabrera, G L; Rodriguez, D M

    1999-05-19

    Three well known plant bioassays, the Allium root chromosome aberration (AL-RAA) assay, the Tradescantia micronucleus (Trad-MCN) assay, and the Tradescantia stamen hair (Trad-SHM) mutation assay were validated in 1991 by the International Programme on Chemical Safety (IPCS) under the auspices of the World Health Organization, and the United Nations Environment Programme (UNEP). These plant bioassays have proven to be efficient tests for chemical screening and especially for in situ monitoring for genotoxicity of environmental pollutants. As a result of this validation study, standard protocols of these three plant bioassays were used by some of the 11 participating countries in the IPCS to carry on genotoxicity tests on air, water and soil as a follow up activity. In the city of Queretaro, Mexico, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the farm crops, polluting the soil. Potentially the pollutants could reach the food chain. For the above reason, soil irrigated with wastewater was sampled and monitored for the presence of genotoxic agents using the above three bioassays. Extracts from soil samples were made using distilled water and organic solvents by shaking the sample for about 12 h under a relatively low temperature (15-20 degrees C). Plant cuttings of Tradescantia or the roots of Allium were treated by submerging them in the extracts. Three replicates of each sample were analyzed in each of the three bioassays. Extracts using DMSO, ethanol and distilled water tested positive in the three bioassays and there were no differences for the genotoxicity of the extracts with the different solvents.

  20. Development of androgen- and estrogen-responsive bioassays, members of a panel of human cell line-based highly selective steroid-responsive bioassays.

    PubMed

    Sonneveld, Edwin; Jansen, Hendrina J; Riteco, Jacoba A C; Brouwer, Abraham; van der Burg, Bart

    2005-01-01

    We have established highly sensitive and specific androgen and estrogen reporter cell lines which we have named AR (androgen receptor) and ERalpha (estrogen receptor alpha) CALUX (Chemically Activated LUciferase eXpression), respectively. Both bioassays are member of a panel of CALUX reporter cell lines derived from the human U2-OS osteosarcoma cell line, all using highly selective reporter constructs based with a basal promoter element linked to multimerized response elements, allowing efficient and specific measurement of compounds interfering with androgen, estrogen, progesterone, and glucocorticoid receptors. The AR CALUX bioassay contains the human androgen receptor and a luciferase reporter construct containing three androgen-responsive elements coupled to a minimal TATA promoter. This cell line was characterized by its stable expression of AR protein, its highly selective response to low levels of different natural and synthetic androgens, and its insignificant response to other nuclear hormone receptor ligands such as estrogens, progestins, and glucocorticoids. The EC50 of dihydrotestosterone (DHT) was found to be 0.13 nM, consistent with the high affinity of this ligand to the human AR. Flutamide, cyproterone acetate, and the environmental contaminants vinclozolin, DDT, methoxychlor, its metabolite HPTE, and penta-BFR showed clear antagonistic activity in the AR CALUX bioassay, competitively inhibiting DHT-mediated transactivation. The established AR CALUX bioassay proved to excel in terms of easy cell line maintenance, high fold induction range (typical 30 times over solvent control), low minimal detection limit (3.6 pM), and high androgen selectivity. Potential applications such as testing the androgenic or estrogenic activity of pure chemicals and pharmaceuticals and complex mixtures (environmental, food, feed, and clinical) are discussed.

  1. Review of Bioassays for Monitoring Fate and Transport ofEstrogenic Endocrine Disrupting Compounds in Water

    SciTech Connect

    CGCampbell@lbl.gov

    2004-01-30

    Endocrine disrupting compounds (EDCs) are recognizedcontaminants threatening water quality. Despite efforts in sourceidentification, few strategies exist for characterization or treatment ofthis environmental pollution. Given that there are numerous EDCs that cannegatively affect humans and wildlife, general screening techniques likebioassays and biosensors provide an essential rapid and intensiveanalysis capacity. Commonly applied bioassays include the ELISA and YESassays, but promising technologies include ER-CALUXa, ELRA, Endotecta,RIANA, and IR-bioamplification. Two biosensors, Endotecta and RIANA, arefield portable using non-cellular biological detection strategies.Environmental management of EDCs in water requires integration ofbiosensors and bioassays for monitoring and assessment.

  2. False-Positive Serum Botulism Bioassay in Miller-Fisher Syndrome.

    PubMed

    Zeylikman, Yuriy; Shah, Vishal; Shah, Umang; Mirsen, Thomas R; Campellone, Joseph V

    2015-09-01

    We describe a patient with acute progressive weakness and areflexia. Both botulism and Miller-Fisher variant of Guillain-Barré syndrome were initial diagnostic considerations, and she was treated with intravenous immunoglobulin and botulinum antitoxin. A mouse bioassay was positive for botulinum toxin A, although her clinical course, electrodiagnostic studies, and cerebrospinal fluid findings supported Miller-Fisher syndrome. This patient's atypical features offer points of discussion regarding the evaluation of patients with acute neuromuscular weakness and emphasize the limitations of the botulism bioassay.

  3. A Brine Shrimp Bioassay for Measuring Toxicity and Remediation of Chemicals

    NASA Astrophysics Data System (ADS)

    Lieberman, Marya

    1999-12-01

    A bioassay using Artemia franciscana (brine shrimp) was adapted to measure the toxicity of household chemicals. One project is described in which students collect dose-response curves for seven commercial flea-killing products. Next, groups of students researched the insecticidal ingredients of the flea products. On the basis of the structures of the active ingredients, they chose remediation methods to make the flea product less toxic to brine shrimp; procedures included copper-catalyzed hydrolysis, adsorption onto activated charcoal, bleach treatment, and photodegradation. No special equipment or supplies are necessary for the bioassay other than the brine shrimp eggs, which can be obtained at any aquarium store.

  4. A marine bioassay test set to assess marine water and sediment quality-its need, the approach and first results.

    PubMed

    Peters, C; Becker, S; Noack, U; Pfitzner, S; Bülow, W; Barz, K; Ahlf, W; Berghahn, R

    2002-10-01

    There is a need for establishing a marine bioassay test set to assess marine water and sediment samples in Germany. The selected marine bioassay test set, two tests for the water phase (with the luminescence bacteria Vibrio fischeri and the algae Phaeodactylum tricornutum Bohlin) and a whole sediment test with the marine amphipod Corophium volutator (Pallas) is described and first results are shown.

  5. Laboratory Bioassays with Three Different Substrates to Test the Efficacy of Insecticides against Various Stages of Drosophila suzukii (Diptera: Drosophilidae).

    PubMed

    Pavlova, Aneliya Koleva; Dahlmann, Melanie; Hauck, Mirjam; Reineke, Annette

    2017-01-01

    Rapid worldwide spread and polyphagous nature of the spotted wing Drosophila Drosophila suzukii Matsumura (Diptera: Drosophilidae) calls for efficient and selective control strategies to prevent severe economic losses in various fruit crops. The use of insecticides is one option for management of this invasive pest insect. Efficacy of insecticides is usually assessed first in laboratory bioassays, which are compounded by the cryptic nature of D. suzukii larvae and the fact that fruits used in bioassays often start to rot and dissolve before larvae have reached the adult stage. Here, we report on laboratory bioassays using three different types of substrates allowing a thorough screening of insecticides for their potential effects against D. suzukii eggs, larvae and adults. Suitability of our bioassays was validated in an assessment of the efficacy of four bioinsecticides and one synthetic insecticide against various developmental stages of D. suzukii Water-apple juice agar used as a bioassay substrate allowed egg counting and observation of larval development due to its transparency, while apple-nutrition medium allowed complete metamorphosis. Use of grape berries in bioassays made it possible to assess effects of an insecticide present on a fruit's surface on oviposition and larval hatch from eggs. Insecticides tested in these three different bioassays with acetamiprid, spinosad or natural pyrethrins as active ingredients achieved a significant D. suzukii control if they were applied before egg deposition. Number of adult flies was significantly reduced if the bioassay medium was treated with an azadirachtin A containing insecticide both before or after egg deposition.

  6. High-throughput mosquito and fly bioassay system for natural and artificial substrates treated with residual insecticides.

    PubMed

    Aldridge, Robert L; Wynn, W Wayne; Britch, Seth C; Allan, Sandra A; Walker, Todd W; Geden, Christopher J; Hogsette, Jerome A; Linthicum, Kenneth J

    2013-03-01

    A high-throughput bioassay system to evaluate the efficacy of residual pesticides against mosquitoes and muscid flies with minimal insect handling was developed. The system consisted of 4 components made of readily available materials: 1) a CO2 anaesthetizing chamber, 2) a specialized aspirator, 3) a cylindrical flat-bottomed glass bioassay chamber assembly, and 4) a customized rack.

  7. 9 CFR 147.16 - Procedure for the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Procedure for the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment). 147.16 Section 147.16 Animals and Animal Products... the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment). This procedure has been...

  8. 9 CFR 147.16 - Procedure for the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Procedure for the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment). 147.16 Section 147.16 Animals and Animal Products... the evaluation of mycoplasma reactors by in vivo bio-assay (enrichment). This procedure has been...

  9. UTILITY OF A FULL LIFE-CYCLE COPEPOD BIOASSAY APPROACH FOR ASSESSMENT OF SEDIMENT-ASSOCIATED CONTAMINANT MIXTURES. (R825279)

    EPA Science Inventory

    Abstract

    We compared a 21 day full life-cycle bioassay with an existing 14 day partial life-cycle bioassay for two species of meiobenthic copepods, Microarthridion littorale and Amphiascus tenuiremis. We hypothesized that full life-cycle tests would bette...

  10. 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.

  11. Enhancement of Colorimetric Response of Enzymatic Reactions by Thermally Evaporated Plasmonic Thin Films: Application to Glial Fibrillary Acidic Protein.

    PubMed

    Abel, Biebele; Kabir, Tabassum S; Odukoya, Babatunde; Mohammed, Muzaffer; Aslan, Kadir

    2015-02-07

    We report the enhancement of the colorimetric response of horseradish peroxidase (HRP) and alkaline phosphatase (AP) in bioassays by thermally evaporated silver, gold, copper and nickel thin films. In this regard, a model bioassay based on biotin-avidin interactions was employed. Biotin groups and enzymes were introduced to all surfaces using a biotinylated linker molecule and avidin, respectively. The colorimetric response of HRP in the model bioassay carried out on the plasmonic thin films were up to 4.4-fold larger as compared to control samples (i.e., no plasmonic thin films), where the largest enhancement of colorimetric response was observed on silver thin films. The colorimetric response of AP on plasmonic thin films was found to be similar to those observed on control samples, which was attributed to the loss of enzymes from the surface during the bioassay steps. The extent of enzymes immobilized on to plasmonic thin films was found to affect the colorimetric response of the model bioassay. These findings allowed us to demonstrate the use of silver thin films for the detection of glial fibrillary acidic protein (GFAP), where the colorimetric response of the standard bioassays for GFAP was enhanced up to 67% as compared to bioassays on glass slides.

  12. Enhancement of Colorimetric Response of Enzymatic Reactions by Thermally Evaporated Plasmonic Thin Films: Application to Glial Fibrillary Acidic Protein

    PubMed Central

    Abel, Biebele; Kabir, Tabassum S.; Odukoya, Babatunde; Mohammed, Muzaffer; Aslan, Kadir

    2015-01-01

    We report the enhancement of the colorimetric response of horseradish peroxidase (HRP) and alkaline phosphatase (AP) in bioassays by thermally evaporated silver, gold, copper and nickel thin films. In this regard, a model bioassay based on biotin-avidin interactions was employed. Biotin groups and enzymes were introduced to all surfaces using a biotinylated linker molecule and avidin, respectively. The colorimetric response of HRP in the model bioassay carried out on the plasmonic thin films were up to 4.4-fold larger as compared to control samples (i.e., no plasmonic thin films), where the largest enhancement of colorimetric response was observed on silver thin films. The colorimetric response of AP on plasmonic thin films was found to be similar to those observed on control samples, which was attributed to the loss of enzymes from the surface during the bioassay steps. The extent of enzymes immobilized on to plasmonic thin films was found to affect the colorimetric response of the model bioassay. These findings allowed us to demonstrate the use of silver thin films for the detection of glial fibrillary acidic protein (GFAP), where the colorimetric response of the standard bioassays for GFAP was enhanced up to 67% as compared to bioassays on glass slides. PMID:25663850

  13. Susceptibility of Bagrada hilaris (Hemiptera: Pentatomidae) to insecticides in laboratory and greenhouse bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field-collected populations of Bagrada hilaris (Burmeister) from Coachella Valley, CA, Imperial Valley, CA, Riverside, CA and Yuma Valley, AZ, were evaluated for susceptibility to several active ingredients representing ten classes of insecticide chemistry. Both leaf-spray and leaf-dip bioassays wer...

  14. Olfactoryresponse of the predatory mite Typhlodromus pyri (Acari: Phytoseiidae) to methyl salicylate in laboratory bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The response of Typhlodromus pyri, a key predator of grapevine rust mite (Calepitrimerus vitis), to MeSA was tested using a Y-tube olfactometer in laboratory bioassays. Six doses ranging from 200 to 0.002 µg of diluted MeSA were tested. Significantly higher proportions of T. pyri preferred MeSA at ...

  15. Determining UV Inactivation of Toxoplasma gondii Oocysts by Using Cell Culture and a Mouse Bioassay

    EPA Science Inventory

    The effect of UV exposure on Toxoplasma gondii oocysts has not been completely defined for use in water disinfection. This study evaluated UV irradiated oocysts by three assays: a SCID mouse bioassay, an in vitro T. gondii oocyst plaque assay (TOP-assay), and a quantitative reve...

  16. Relationships of maternal and fetal weight changes in developmental toxicology bioassays

    EPA Science Inventory

    Standard developmental toxicology bioassays are designed to identify agents with the potential to induce adverse effects in the embryo/fetus. Guidelines require the inclusion of a dose level(s) that induces “overt maternal toxicity”. The common occurrence of dose levels at which ...

  17. Efficiency of several cultural methods and a chick bioassay to recover dry stressed Campylobacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aims of the study were to evaluate the efficacy of 5 enrichment procedures for recovery of dry-atmospheric-temperature stressed C. jejuni and C. coli and determine the viable status of the non-culturable strains using a chick bioassay. Sterile chick paper pads (PP) and filter papers (FP) were i...

  18. Rapid Bioassessment and In Situ Bioassay: Cost Effective Tools for Environmental Impact Assessment

    SciTech Connect

    Wike, L.D.

    2002-08-23

    Environmental impact can be difficult to assess, especially at the ecosystem level. Any impact assessment methodology that can give cost effective and timely results is highly desirable. Rapid bioassessment (RBA) is cost effective and produces timely results. Several types of RBA have been used at the Savannah River Site (SRS) to assess stream conditions, including the Index of Biotic Integrity (IBI) based on fish community characteristics, and various techniques using aquatic macroinvertebrate species diversity and abundance. In an attempt to broaden the applicability of the RBA concept, we have also begun to develop RBA techniques for seep-fed wetlands and terrestrial habitats. These techniques will focus on vertebrate and macroinvertebrate assemblages for seep-fed wetlands and arthropod assemblages for terrestrial habitats. In situ bioassay is another technique that could be used for rapid and economical assessment of the effects of anthropogenic disturbance. We propose the development of two methods of in situ bioassay that can address bioavailability of constituents of concern. The use of caged bioassay organisms can be applied to terrestrial systems such as capped or existing waste sites using the common house cricket. Another proposed bioassay could use a resident species, such as the imported red fire ant, which is found in disturbed habitats and open areas such as waste sites. Combining in situ techniques with RBA methodologies has the potential to provide a comprehensive assessment of chemical and physical impacts to a wide range of ecosystem types.

  19. A bioassay approach for determining the effect of cooking on fumonisin today

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fumonisin mycotoxins are found in corn and corn-based foods, but the effect of cooking on fumonisin toxicity has not been studied extensively. Rat feeding studies were used as an in vivo bioassay to compare the toxicity of extrusion cooked and nixtamalized (alkaline cooked) fumonisin-contaminated p...

  20. Applicability of a yeast bioassay in the detection of steroid esters in hair.

    PubMed

    Becue, Ilse; Bovee, Toine F H; Van Poucke, Christof; Groot, Maria J; Nielen, Michel W F; Van Peteghem, Carlos

    2011-01-01

    The aim of the present study was to demonstrate the applicability of a yeast androgen and estrogen bioassay in the detection of steroid esters in hair samples of animals treated with a hormone ester cocktail. The outcome of the activity screenings was critically compared with the results previously obtained with LC-MS/MS analysis. Hair samples of one pour-on treated animal, 10 ml DMSO containing 25 mg estradiol benzoate (EB), 60 mg testosterone decanoate (TD) and 60 mg testosterone cypionate (TC), were selected and analyzed with the androgen and estrogen yeast bioassay. Results showed that by the introduction of a hydrolysis step, bioassays can be used to screen for the presence of hormone esters in hair samples. Based on the difference in fluorescence responses between the non-hydrolyzed and the hydrolyzed hair samples, it was possible to detect the presence of EB up to at least 56 days after a single pour-on treatment and to detect the presence of TC and TD up to at least 14 days after the treatment. Although the LC-MS/MS analysis could detect TC and TD up to 49 days after treatment, bioassays have the advantage that they can also detect any (un)known steroid ester.

  1. Maternal and fetal toxicity in developmental toxicology bioassays: Weight changes and their biological significance

    EPA Science Inventory

    Standard developmental toxicology bioassays are designed to identify agents with the potential to induce adverse effects in the embryo/fetus. Guidelines call for the inclusion of a dose level(s) that induces “overt maternal toxicity.” The possibility that general maternal toxicit...

  2. Risk assessment for selected xenobiotics by bioassay methods with higher plants

    NASA Astrophysics Data System (ADS)

    Günther, Petra; Pestemer, Wilfried

    1990-05-01

    Different bioassays with higher plants were approved for use in a bioassay procedure for testing of xenobiotics according to the German Chemicals Act. Selected environmental pollutants (atrazine, cadmium chloride, 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, thiourea), all from a list of reference chemicals, were tested with these methods. Dose-response curves for growth of oats and turnips were evaluated in soil and vermiculite (nonsorptive substrate), and availability to plants was calculated by comparing the EC50 values for one chemical in both substrates. The most active chemical was atrazine, followed by 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, cadmium chloride, and thiourea. The least available compound to plants was pentachlorophenol, tested with turnips ( Brassica rapa var. rapa). The strongest inhibition of germination, demonstrated in an in vitro assay with garden cress ( Lepidium sativum), was found with 2,6-dichlorobenzonitrile, the lowest with atrazine. The effect of an extended exposure of the plants to the chemicals was evaluated in a long-term bioassay with oats ( Avena sativa) in hydroponic culture. Several dose-response curves during the growing period were derived. It was found that the EC50 values for atrazine and thiourea decreased markedly during the first four weeks; thereafter the changes were much smaller. As an overall conclusion, a bioassay procedure is proposed that can be included in the graduated plan recommended by the German Chemicals Act.

  3. Zebrafish Bioassay-Guided Natural Product Discovery: Isolation of Angiogenesis Inhibitors from East African Medicinal Plants

    PubMed Central

    Crawford, Alexander D.; Liekens, Sandra; Kamuhabwa, Appolinary R.; Maes, Jan; Munck, Sebastian; Busson, Roger; Rozenski, Jef; Esguerra, Camila V.; de Witte, Peter A. M.

    2011-01-01

    Natural products represent a significant reservoir of unexplored chemical diversity for early-stage drug discovery. The identification of lead compounds of natural origin would benefit from therapeutically relevant bioassays capable of facilitating the isolation of bioactive molecules from multi-constituent extracts. Towards this end, we developed an in vivo bioassay-guided isolation approach for natural product discovery that combines bioactivity screening in zebrafish embryos with rapid fractionation by analytical thin-layer chromatography (TLC) and initial structural elucidation by high-resolution electrospray mass spectrometry (HRESIMS). Bioactivity screening of East African medicinal plant extracts using fli-1:EGFP transgenic zebrafish embryos identified Oxygonum sinuatum and Plectranthus barbatus as inhibiting vascular development. Zebrafish bioassay-guided fractionation identified the active components of these plants as emodin, an inhibitor of the protein kinase CK2, and coleon A lactone, a rare abietane diterpenoid with no previously described bioactivity. Both emodin and coleon A lactone inhibited mammalian endothelial cell proliferation, migration, and tube formation in vitro, as well as angiogenesis in the chick chorioallantoic membrane (CAM) assay. These results suggest that the combination of zebrafish bioassays with analytical chromatography methods is an effective strategy for the rapid identification of bioactive natural products. PMID:21379387

  4. Evaluation of soil bioassays for use at Washington state hazardous waste sites: A pilot study

    SciTech Connect

    Blakley, N.; Norton, D.; Stinson, M.; Boyer, R.

    1994-12-31

    The Washington State Department of Ecology (Ecology) is developing guidelines to assess soil toxicity at hazardous waste sites being investigated under the Washington Model Toxics Control Act Cleanup Regulation. To evaluate soil toxicity, Ecology selected five bioassay protocols -- Daphnia, Earthworm, Seedling, Fathead Minnow, and Frog Embryo Teratogenesis Assay Xenopus (FETAX) -- for use as screening level assessment tools at six State hazardous waste sites. Sites contained a variety of contaminants including metals, creosote, pesticides, and petroleum products (leaking underground storage tanks). Three locations, representing high, medium, and low levels of contamination, were samples at each site. In general, the high contaminant samples resulted in the highest toxic response in all bioassays. The order of site toxicity, as assessed by overall toxic response, is creosote, petroleum products, metals, and pesticides. Results indicate that human health standards, especially for metals, may not adequately protect some of the species tested. The FETAX bioassay had the greatest overall number of toxic responses and lowest variance. The seedling and Daphnia bioassays had lower and similar overall toxic response results, followed by the earthworm and fathead minnow. Variability was markedly highest for the seedling. The Daphnia and fathead minnow variability were similar to the FETAX level, while the earthworm variability was slightly higher.

  5. Determination of Biochemical Oxygen Demand of Area Waters: A Bioassay Procedure for Environmental Monitoring

    ERIC Educational Resources Information Center

    Riehl, Matthew

    2012-01-01

    A graphical method for determining the 5-day biochemical oxygen demand (BOD5) for a body of water is described. In this bioassay, students collect a sample of water from a designated site, transport it to the laboratory, and evaluate the amount of oxygen consumed by naturally occurring bacteria during a 5-day incubation period. An accuracy check,…

  6. Polycyclic aromatic hydrocarbons bioavailability in industrial and agricultural soils: Linking SPME and Tenax extraction with bioassays.

    PubMed

    Guo, Meixia; Gong, Zongqiang; Li, Xiaojun; Allinson, Graeme; Rookes, James; Cahill, David

    2017-06-01

    The aims of this study were to evaluate the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in industrial and agricultural soils using chemical methods and a bioassay, and to study the relationships between the methods. This was conducted by comparing the quantities of PAHs extracted from two manufactured gas plant (MGP) soils and an agricultural soil with low level contamination by solid-phase micro-extraction (SPME) and Tenax-TA extraction with the quantities taken up by the earthworm (Eisenia fetida). In addition, a biodegradation experiment was conducted on one MGP soil (MGP-A) to clarify the relationship between PAH removal by biodegradation and the variation in PAH concentrations in soil pore water. Results demonstrated that the earthworm bioassay could not be used to examine PAH bioavailability in the tested MGP soils; which was the case even in the diluted MGP-A soils after biodegradation. However, the bioassay was successfully applied to the agricultural soil. These results suggest that earthworms can only be used for bioassays in soils with low toxicity. In general, rapidly desorbing concentrations extracted by Tenax-TA could predict PAH concentrations accumulated in earthworms (R(2)=0.66), while SPME underestimated earthworm concentrations by a factor of 2.5. Both SPME and Tenax extraction can provide a useful tool to predict PAH bioavailability for earthworms, but Tenax-TA extraction was proven to be a more sensitive and precise method than SPME for the prediction of earthworm exposure in the agricultural soil.

  7. APPLICATION OF PLANT AND EARTHWORM BIOASSAYS TO EVALUATE REMEDIATION OF A LEAD-CONTAMINATED SOIL

    EPA Science Inventory

    Earthworm acute toxicity, plant seed germination/root elongation (SG/RE) and plant genotoxicity bioassays were employed to evaluate the remediation of a lead-contaminated soil. The remediation involved removal of heavy metals by a soil washing/soil leaching treatment process. A p...

  8. The Intersection of CMOS Microsystems and Upconversion Nanoparticles for Luminescence Bioimaging and Bioassays

    PubMed Central

    Wei, Liping.; Doughan, Samer.; Han, Yi.; DaCosta, Matthew V.; Krull, Ulrich J.; Ho, Derek.

    2014-01-01

    Organic fluorophores and quantum dots are ubiquitous as contrast agents for bio-imaging and as labels in bioassays to enable the detection of biological targets and processes. Upconversion nanoparticles (UCNPs) offer a different set of opportunities as labels in bioassays and for bioimaging. UCNPs are excited at near-infrared (NIR) wavelengths where biological molecules are optically transparent, and their luminesce in the visible and ultraviolet (UV) wavelength range is suitable for detection using complementary metal-oxide-semiconductor (CMOS) technology. These nanoparticles provide multiple sharp emission bands, long lifetimes, tunable emission, high photostability, and low cytotoxicity, which render them particularly useful for bio-imaging applications and multiplexed bioassays. This paper surveys several key concepts surrounding upconversion nanoparticles and the systems that detect and process the corresponding luminescence signals. The principle of photon upconversion, tuning of emission wavelengths, UCNP bioassays, and UCNP time-resolved techniques are described. Electronic readout systems for signal detection and processing suitable for UCNP luminescence using CMOS technology are discussed. This includes recent progress in miniaturized detectors, integrated spectral sensing, and high-precision time-domain circuits. Emphasis is placed on the physical attributes of UCNPs that map strongly to the technical features that CMOS devices excel in delivering, exploring the interoperability between the two technologies. PMID:25211198

  9. SUPERNUMERARY RIBS IN DEVELOPMENTAL TOXICITY BIOASSAYS AND IN HUMAN POPULATIONS: INCIDENCE AND BIOLOGICAL SIGNIFICANCE

    EPA Science Inventory

    Abstract
    Supernumerary or accessory ribs (SNR), either lumbar (LSNR) or cervical (CSNR) are a common finding in standard developmental toxicology bioassays. The biological significance of these anomalies within the regulatory arena has been problematic and the subject of some...

  10. Bayesian Analysis for Linearized Multi-Stage Models in Quantal Bioassay.

    ERIC Educational Resources Information Center

    Kuo, Lynn; Cohen, Michael P.

    Bayesian methods for estimating dose response curves in quantal bioassay are studied. A linearized multi-stage model is assumed for the shape of the curves. A Gibbs sampling approach with data augmentation is employed to compute the Bayes estimates. In addition, estimation of the "relative additional risk" and the "risk specific…

  11. Development of bioassay techniques with extracts from semi-permeable membrane devices (SPMDs)

    SciTech Connect

    Metcalfe, T.L.; White, P.; Mackay, D.; Metcalfe, C.

    1995-12-31

    Semi-permeable membrane devices (SPMDs), consisting of polyethylene bags filled with triolein, have been used to monitor for lipophilic organic contaminants in water. Although extracts from SPMDs have most often been analyzed for concentrations of organic contaminants, there is also the potential to monitor the toxicity of these extracts using in vitro and in vivo bioassays. SPMDs were deployed for four weeks at several sites along a corridor extending from Peche Island in the Detroit River to Pelee Island in western Lake Erie to monitor the distribution of toxic organic contaminants in the water. Analysis of the extracts from the SPMDs for concentrations of PCBs and other organochlorine compounds, and polynuclear aromatic hydrocarbons (PAHs) indicated that the regions in the Detroit River within the Trenton Channel and near Zug Island were the most highly contaminated. Bioassays conducted with extracts from the SPMDs included the in vitro SOS Chromotest for genotoxic activity, an acute lethality test with Daphnia magna, and a fish embryotoxicity test with embryos of Japanese medaka (Oryzias latipes). These bioassay data generally indicated that the toxicity and concentrations of organic contaminants in the SPMD extracts were correlated. This study indicates that there is potential to use short-term bioassays of extracts from SPMDs to monitor for in situ contamination in the aquatic environment.

  12. OBSERVATIONS ON THE 10-DAY CHIRONOMUS TENTANS SURVIVAL AND GROWTH BIOASSAY IN EVALUATING GREAT LAKES SEDIMENTS

    EPA Science Inventory

    A 10-day bioassay with larval chironomids (Chironomus tentans) was used to evaluate sediment samples from harbors at Michigan City, IN, St. Joseph, MI, Grand Haven, MI and Toledo, OH for toxicity, based on the endpoints of survival, dry weight, and growth. Larval responses in se...

  13. Experience with NQA-1 quality assurance standards applied to in vitro bioassay

    SciTech Connect

    Bihl, D.E.; MacLellan, J.A.

    1991-10-01

    On June 1, 1990, the large (about 4000 samples per year) excreta bioassay program at the Hanford Site ceased abruptly when the contract with the bioassay laboratory was terminated. An intense, high-priority effort was begun to replace the services on an interim basis until a new contract could be procured. Despite the urgency to get the excreta bioassay program going again, the Hanford Internal Dosimetry Program was constrained to use only labs that could meet stringent quality assurance (QA) requirements, even during the interim period. The QA requirements were based on NQA-1 with selected additions from the Environmental Protection Agency's QAMS 005/80 (EPA 1983) and the American Society for Testing and Materials' C 1009-83 (ASTM 1984). This constraint was driven both by legal reasons and by the Hanford Site contractors and workers not wanting the quality of the data to be sacrificed. Finding labs that could (1) handle the large throughput, (2) meet the technical requirements, and (3) pass the QA audit proved more difficult than first anticipated. This presentation focuses on the QA requirements that the labs had to meet and how those very broad requirements were applied specifically to excreta bioassay. 5 refs.

  14. Utilizing high throughput bioassays to characterize the bioactivity of complex environmental samples

    EPA Science Inventory

    Bioassays can be employed to evaluate the integrated effects of complex mixtures of both known and unidentified contaminants present in environmental samples. However, such methods have typically focused on one or a few bioactivities despite the fact that the chemicals in a mixtu...

  15. Development of a novel, bioluminescence-based, fungal bioassay for toxicity testing.

    PubMed

    Weitz, Hedda J; Campbell, Colin D; Killham, Ken

    2002-07-01

    Naturally bioluminescent fungi, Armillaria mellea and Mycena citricolor, were used to develop a novel, bioluminescence-based bioassay for toxicity testing. Bioassays were carried out to assess the toxicity of 3,5-dichlorophenol (3,5-DCP), pentachlorophenol (PCP), copper and zinc. The results suggested that 60 min was a suitable exposure time for the bioassay. Light reduction was observed in response to 3,5-DCP, PCP and Cu for both A. mellea and M. citricolor, but to Zn only for A. mellea. Armillaria mellea was significantly less sensitive to 3,5-DCP and PCP than M. citricolor. The EC50 values for A. mellea and M. citricolor were similar to EC50 values for 3,5-DCP, PCP and Cu (but not Zn) of bioluminescence-based bacterial biosensors. They were also similar to EC50 values for Cu and Zn of a bioluminescence-based yeast biosensor. The results highlighted the importance of using both prokaryotic and eukaryotic biosensors. The novel bioassay provides a rapid and sensitive method to assess bioavailability of pollutants as well as a method to determine their toxicity to filamentous fungi. It also expands the range of organisms that can be used for bioluminescence-based toxicity testing by complementing existing biosensors.

  16. The use of bioassay to determine the effects of cooking on the toxicity of fumonisins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fumonisins are mycotoxin contaminants of maize. Fumonisin B1 (FB1), the most common and toxic fumonisin, causes species-specific diseases in animals, is carcinogenic to rodents, and induces neural tube defects (NTD) in LM/Bc and CD1 mouse bioassays. The human health implications associated with FB1...

  17. Using a Macroalgal δ15N Bioassay to Detect Cruise Ship Waste Water Effluent Inputs

    EPA Science Inventory

    Nitrogen stable isotopes are a powerful tool for tracking sources of N to marine ecosystems. I used green macroalgae as a bioassay organism to evaluate if the δ15N signature of cruise ship waste water effluent (CSWWE) could be detected in Skagway Harbor, AK. Opportunistic green...

  18. A BIOASSAY THAT IDENTIFIES POSTNATAL FUNCTIONAL DEFICITS IN MICE PRENATALLY EXPOSED TO XENOBIOTICS

    EPA Science Inventory

    Experimental strategies to evaluate adverse postnatal effects due to prenatal exposure exist for many organ systems. Often, however, there is insufficient information to suggest that a particular organ system(s) may be sensitive to the test agent. A single bioassay to identify ...

  19. An Estuarine Fish Bioassay for Sensitive Biomonitoring of Oil-related Contamination

    EPA Science Inventory

    An embryonic and larval bioassay using the estuarine fish, Fundulus heteroclitus, was modified for the rapid detection of bioavailable compounds that act through the aryl hydrocarbon receptor (AhR). The early development of fishes is particularly sensitive to AhR agonists, such ...

  20. USE OF SALMONELLA MICROSUSPENSION BIOASSAY TO DETECT THE MUTGENICITY OF MUNITIONS COMPOUNDS AT LOW CONCENTRATIONS

    EPA Science Inventory



    Use of a Salmonella Microsuspension Bioassay to Detect the Mutagenicity of
    Munitions Compounds at Low Concentrations

    Abstract

    Past production and handling of munitions has resulted in soil contamination at various military facilities. Depending on...

  1. Does co-extracted dissolved organic carbon cause artefacts in cell-based bioassays?

    PubMed

    Neale, Peta A; Escher, Beate I

    2014-08-01

    Bioanalytical tools are increasingly being employed for water quality monitoring, with applications including samples that are rich in natural organic matter (or dissolved organic carbon, DOC), such as wastewater. While issues associated with co-extracted DOC have been identified for chemical analysis and for bioassays with isolated enzymes, little is known about its effect on cell-based bioassays. Using mixture experiments as diagnostic tools, this study aims to assess whether different molecular weight fractions of wastewater-derived DOC adversely affect cell-based bioassays, specifically the bioluminescence inhibition test with the bacteria Vibrio fischeri, the combined algae assay with Pseudokirchneriella subcapitata and the human cell line AREc32 assay for oxidative stress. DOC did not cause suppressive effects in mixtures with reference compounds. Binary mixtures further indicated that co-extracted DOC did not disturb cell-based bioassays, while slight deviations from toxicity predictions for low molecular weight fractions may be partially due to the availability of natural components to V. fischeri, in addition to organic micropollutants.

  2. Paper-based chromatic toxicity bioassay by analysis of bacterial ferricyanide reduction.

    PubMed

    Pujol-Vila, F; Vigués, N; Guerrero-Navarro, A; Jiménez, S; Gómez, D; Fernández, M; Bori, J; Vallès, B; Riva, M C; Muñoz-Berbel, X; Mas, J

    2016-03-03

    Water quality assessment requires a continuous and strict analysis of samples to guarantee compliance with established standards. Nowadays, the increasing number of pollutants and their synergistic effects lead to the development general toxicity bioassays capable to analyse water pollution as a whole. Current general toxicity methods, e.g. Microtox(®), rely on long operation protocols, the use of complex and expensive instrumentation and sample pre-treatment, which should be transported to the laboratory for analysis. These requirements delay sample analysis and hence, the response to avoid an environmental catastrophe. In an attempt to solve it, a fast (15 min) and low-cost toxicity bioassay based on the chromatic changes associated to bacterial ferricyanide reduction is here presented. E. coli cells (used as model bacteria) were stably trapped on low-cost paper matrices (cellulose-based paper discs, PDs) and remained viable for long times (1 month at -20 °C). Apart from bacterial carrier, paper matrices also acted as a fluidic element, allowing fluid management without the need of external pumps. Bioassay evaluation was performed using copper as model toxic agent. Chromatic changes associated to bacterial ferricyanide reduction were determined by three different transduction methods, i.e. (i) optical reflectometry (as reference method), (ii) image analysis and (iii) visual inspection. In all cases, bioassay results (in terms of half maximal effective concentrations, EC50) were in agreement with already reported data, confirming the good performance of the bioassay. The validation of the bioassay was performed by analysis of real samples from natural sources, which were analysed and compared with a reference method (i.e. Microtox). Obtained results showed agreement for about 70% of toxic samples and 80% of non-toxic samples, which may validate the use of this simple and quick protocol in the determination of general toxicity. The minimum instrumentation

  3. Seasonal distribution of phytoplankton assemblages and nutrient-enriched bioassays as indicators of nutrient limitation of phytoplankton growth in Gwangyang Bay, Korea

    NASA Astrophysics Data System (ADS)

    Baek, Seung Ho; Kim, Dongseon; Son, Moonho; Yun, Suk Min; Kim, Young Ok

    2015-09-01

    To assess the effect of nutrient limitation on phytoplankton growth, and its influence on seasonal variation in phytoplankton community structure, we investigated abiotic and biotic factors in surface and bottom waters at 20 stations in inner and offshore areas of Gwangyang Bay, Korea. Algal bioassay experiments were also conducted using surface water, to assess the effects of nutrient addition on the phytoplankton assemblages. The fate of major nutrients in the bay was strongly dependent on the discharge of freshwater from the Seomjin River. River flow during the rainy season provides a high nitrogen (N) influx, pushing the system toward stoichiometric phosphorus (P) limitation. However, at some times during the rainy season there was insufficient N to maintain phytoplankton growth because it was rapidly consumed through nutrient uptake by phytoplankton under stratified environmental conditions. Diatoms made a relatively large contribution to total phytoplankton biomass. The dominant diatoms, particularly in winter and summer, were Skeletonema marinoi-dohrnii complex and Skeletonema tropicum, respectively, while Eucampia zodiacus and the cryptophyte Cryptomonas spp. dominated in spring and autumn, respectively, comprising more than 75% of the community at most stations. In the bioassay experiments the phytoplankton biomass increased by 30-600% in the +N (added nitrogen) and +NP (added nitrogen and phosphorus) treatments relative to the control and the +P (added phosphorus) treatments, indicating that phytoplankton growth can respond rapidly to pulsed nitrate loading events. Based on the algal bioassay and the field survey, the abrupt input of high nutrient levels following rainfall stimulated the growth of diatom assemblages including the Skeletonema genus. Our results demonstrate that the growth of centric diatoms was enhanced by inputs of N and Si, and that the concentrations of these nutrients may be among the most important factors controlling phytoplankton

  4. A bioassay to measure cytotoxicity of plasma from patients treated with mitomycin C.

    PubMed

    Marshall, R S; Erlichman, C; Rauth, A M

    1985-11-01

    The unpredictable clinical toxicity observed in patients treated with mitomycin C and the observation that this agent must be reduced to an active form before alkylating target molecules have led to the development of a bioassay which is capable of detecting biologically active forms of mitomycin C in the plasma of drug-treated patients. The bioassay makes use of a repair-deficient mutant of Chinese hamster ovary cells, UV-20, which is 40 to 60 times more sensitive to mitomycin C than its wild-type parent. A standard curve relating in vitro cell colony-forming ability of UV-20 versus drug concentration in the plating medium has been determined. Mitomycin C levels in patient plasma as low as 1 ng/ml can be detected, compared to the 5-ng/ml limit of detection obtained with a high-pressure liquid chromatography assay for the parent compound. This assay has been utilized to detect active drug in plasma obtained from patients with colorectal cancer treated with mitomycin C as a single agent. At the completion of drug injection, serial blood samples were collected in heparinized tubes, and aliquots of plasma were extracted and assayed for mitomycin C levels by high-pressure liquid chromatography, diluted and assayed directly for their toxicity for UV-20 cells, or frozen at -20 degrees C to be assayed at a later time. The activity detected by immediate bioassay was stable up to 2 mo in frozen samples. Plasma pharmacokinetics determined by the bioassay in seven patients were no different than those determined by high-pressure liquid chromatography. No stable, cytotoxic species other than the parent compound were detected by the bioassay in the plasma of patients treated with mitomycin C.

  5. Alternative bioassay for the detection of saxitoxin using the speckled cockroach (Nauphoeta cinerea).

    PubMed

    Ruebhart, David R; Radcliffe, Wendy L; Eaglesham, Geoffrey K

    2011-01-01

    Paralytic shellfish poisoning (PSP) toxins produced by cyanobacteria pose a risk to public health as they occur in drinking water reservoirs and recreational lakes and accumulate in the food chain. One of these PSP toxins, saxitoxin (STX) is one of the most toxic nonprotein substances known. Accordingly, there is a requirement to monitor for these toxins. The standard bioassay used to detect these toxins is the mouse bioassay; however, its use is constrained by animal ethics guidelines and practical considerations. Reported here is the use of the globally distributed speckled cockroach Nauphoeta cinerea as a bioassay test organism for the selective detection of PSP toxicity of Anabaena circinalis aqueous extract and STX. N. cinerea was shown to be tolerant to pure cylindrospermopsin (CYN) and microcystin-LR (MC-LR) at doses 10-fold greater than mouse LD₅₀ values while being sensitive to STX. Similarly, N. cinerea was shown to be tolerant of toxin-containing aqueous extracts of Cylindrospermopsis raciborskii, Microcystis aeruginosa, and Nodularia spumigena while being sensitive to A. circinalis. Peak sensitivity to STX was 60 min postinjection with a KD₅₀ of 31.2 ng/g body weight. While this was approximately 3-fold less sensitive than the mouse bioassay, the insect test organism was around 34-fold smaller in mass than a mouse (20 g); thus one-tenth the amount of toxin in absolute quantity was required to reach an ED₅₀ level. The N. cinerea bioassay presents a selective test for PSP toxicity that is rapid, economical, efficient, and simple to perform.

  6. Quality of water types in Ukraine evaluated by WaterTox bioassays.

    PubMed

    Arkhipchuk, V V; Malinovskaya, M V

    2002-01-01

    The quality of river, ground-, and tap water was analyzed using the basic set of WaterTox bioassays [Daphnia (Daphnia magna), Hydra (Hydra attenuata), and lettuce (Lactuca sativa)] as well as two additional bioassays, onion (Allium cepa) and microalga (Selenastrum gracile). Samples of these waters were also concentrated fivefold using a solid-phase procedure. The results of the Daphnia and Hydra bioassays showed that the winter and spring concentrated and nonconcentrated samples from the Dnieper and Desna rivers, the main water supply sources for Kiev, were nontoxic. In spring, after concentration, the two river samples brought about the same relative decrease in the lettuce root length (by 35%, p < 0.001), where the Desna River sample considerably reduced (by 79.1%, p < 0.001) the number of microalga cells. Samples of groundwater from countryside wells studied in autumn in several villages of the Kiev region were toxic mainly to Hydra (sublethal effects were found in 11%-78%) and lettuce (the root length decreased 15%-56%). Studies of tap water samples from two of the largest cities of Ukraine, Kiev and Kharkiv, were found to be nontoxic to both plants, lettuce and onion, but showed increased sublethal and lethal effects on both animals, Daphnia and Hydra, as well as a reduced number of microalgae. Different bioassays were sensitive to varying degrees to different water types. This reinforces the necessity of using sets of bioassays in toxicity evaluation. In general, all the tested water samples demonstrated some toxicity. These data suggest that drinking water quality in Ukraine needs improvement.

  7. Effects of wind speed on aerosol spray penetration in adult mosquito bioassay cages.

    PubMed

    Hoffmann, W Clint; Fritz, Bradley K; Farooq, Muhammad; Cooperband, Miriam F

    2008-09-01

    Bioassay cages are commonly used to assess efficacy of insecticides against adult mosquitoes in the field. To correlate adult mortality readings to insecticidal efficacy and/or spray application parameters properly, it is important to know how the cage used in the bioassay interacts with the spray cloud containing the applied insecticide. This study compared the size of droplets, wind speed, and amount of spray material penetrating cages and outside of cages in a wind tunnel at different wind speeds. Two bioassay cages, Center for Medical, Agricultural and Veterinary Entomology (CMAVE) and Circle, were evaluated. The screen materials used on these cages reduced the size of droplets, wind speed, and amount of spray material inside the cages as compared to the spray cloud and wind velocity outside of the cages. When the wind speed in the dispersion tunnel was set at 0.6 m/sec (1.3 mph), the mean wind speed inside of the CMAVE Bioassay Cage and Circle Cage was 0.045 m/sec (0.10 mph) and 0.075 m/sec (0.17 mph), respectively. At air velocities of 2.2 m/sec (4.9 mph) in the dispersion tunnel, the mean wind speed inside of the CMAVE Bioassay Cage and Circle Cage was 0.83 m/sec (1.86 mph) and 0.71 m/sec (1.59 mph), respectively. Consequently, there was a consistent 50-70% reduction of spray material penetrating the cages compared to the spray cloud that approached the cages. These results provide a better understanding of the impact of wind speed, cage design, and construction on ultra-low-volume spray droplets.

  8. Bioassays for the detection of chemicals that can form bioactivation-dependent reactive free radicals

    SciTech Connect

    Sanderson, J.T.; Commandeur, J.N.M.; Wezel, A. van; Vermeulen, N.P.E. . Div. of Molecular Toxicology National Inst. for Coastal and Marine Management, Den Haag )

    1999-06-01

    In vitro bioassays were developed for the detection of chemicals that can be bioactivated to reactive free radical species in microsomal fractions. Two methods were deployed, a down-scaled spectrophotometric method for the detection of chemicals that can cause lipid peroxidation using the measurement of thiobarbituric acid-reactive substances (TBARS) and a fluorometric method for the detection of chemicals that can undergo redox cycling to generate superoxide radicals based on the detection of hydrogen peroxide. The response of these systems to prototypical and environmentally relevant chemicals, including tetrachloromethane and paraquat, was examined. The detection limit of the lipid peroxidation bioassay, based on the formation of TBARS, was about 1 [micro]M for tetrachloromethane; that of the bioassay for redox cyclers, based on the production of hydrogen peroxide, was about 2 [micro]M for paraquat and about 100-fold lower for the potent redox cycler 2,3,5,6-tetramethylbenzoquinone (TMBQ). Several binary mixtures of chemicals were tested for potential nonadditive effects in both in vitro systems. Some antagonistic effects among halogenated methanes were observed in the lipid peroxidation assay. In the hydrogen peroxide production assay, greater than additive effects were seen between small concentrations of paraquat and TMBQ. A number of surface water concentrates from several locations in The Netherlands, with various levels of chemical contamination, exhibited a weak response in the hydrogen peroxide production assay. Acetone was found to interfere with the response of the bioassay to redox cyclers and, therefore, the water concentrates (originally in acetone) were transferred to ethanol prior to testing. A good correlation was observed between the response of the water concentrates in the hydrogen peroxide production assay and their acute toxicity in Daphnia magna. No correlation was observed between this bioassay response and toxicity in the Microtox

  9. Scientific Considerations for Evaluating Cancer Bioassays Conducted by the Ramazzini Institute

    PubMed Central

    Caldwell, Jane C.; Jinot, Jennifer; Evans, Marina V.; Cote, Ila; Vandenberg, John J.

    2013-01-01

    Background: The Ramazzini Institute (RI) has completed nearly 400 cancer bioassays on > 200 compounds. The European Food Safety Authority (EFSA) and others have suggested that study design and protocol differences between the RI and other laboratories by may contribute to controversy regarding cancer hazard findings, principally findings on lymphoma/leukemia diagnoses. Objective: We aimed to evaluate RI study design, protocol differences, and accuracy of tumor diagnoses for their impact on carcinogenic hazard characterization. Methods: We analyzed the findings from a recent Pathology Working Group (PWG) review of RI procedures and tumor diagnoses, evaluated consistency of RI and other laboratory findings for chemicals identified by the RI as positive for lymphoma/leukemia, and examined evidence for a number of other issues raised regarding RI bioassays. The RI cancer bioassay design and protocols were evaluated in the context of relevant risk assessment guidance from international authorities. Discussion: Although the PWG identified close agreement with RI diagnoses for most tumor types, it did not find close agreement for lymphoma/leukemia of the respiratory tract or for neoplasms of the inner ear and cranium. Here we discuss a) the implications of the PWG findings, particularly lymphoma diagnostic issues; b) differences between RI studies and those from other laboratories that are relevant to evaluating RI cancer bioassays; and c) future work that may help resolve some concerns. Conclusions: We concluded that a) issues related to respiratory tract infections have complicated diagnoses at that site (i.e., lymphoma/leukemia), as well as for neoplasms of the inner ear and cranium, and b) there is consistency and value in RI studies for identification of other chemical-related neoplasia. Citation: Gift JS, Caldwell JC, Jinot J, Evans MV, Cote I, Vandenberg JJ. 2013. Scientific considerations for evaluating cancer bioassays conducted by the Ramazzini Institute

  10. Confirmation of botulism in birds and cattle by the mouse bioassay and Endopep-MS.

    PubMed

    Hedeland, Mikael; Moura, Hercules; Båverud, Viveca; Woolfitt, Adrian R; Bondesson, Ulf; Barr, John R

    2011-09-01

    There have been several outbreaks of botulism among poultry and wild birds in Sweden in recent years. The National Veterinary Institute of Sweden (SVA) has identified botulinum neurotoxin (BoNT)/C1 or the mosaic BoNT/C1D using the mouse bioassay. This is believed to be the first report on the application of the Endopep mass spectrometry (Endopep-MS) method to selected clinical animal (serum and liver) samples and a feed sample that had previously given positive test results with the mouse bioassay. In the mouse bioassay eight of the eleven samples were found to be neutralized by both BoNT/C1 and /D antitoxins; the other three were neutralized only by BoNT/C1 antitoxin, but the mice showed a prolonged survival time when the samples had been treated with /D antitoxin. The Endopep-MS analysis, on the other hand, demonstrated only BoNT/C1 activity for all eleven samples. This suggests that at least eight of the samples were of the chimeric toxin type BoNT/C1D, where the enzymically active site is identical to that of BoNT/C1, while other parts of the protein contain sequences of BoNT/D. This is the first step of a cross-validation between the established mouse bioassay and the Endopep-MS of serotypes BoNT/C1 and /C1D. Endopep-MS is concluded to have potential as an attractive alternative to the mouse bioassay.

  11. Bioassay-directed fractionation and chemical identification of mutagens in bioremediated soils.

    PubMed Central

    Brooks, L R; Hughes, T J; Claxton, L D; Austern, B; Brenner, R; Kremer, F

    1998-01-01

    Soil from a Superfund site (Reilly Tar Site, St. Louis Park, Minnesota) contaminated with polycyclic aromatic hydrocarbons (PAHs) from creosote was treated with several bioremediation technologies including bioslurry (BS), biopile (BP), compost (CMP), and land treatment (LT). These treatment technologies are being evaluated in pilot scale laboratory systems by the U.S. Environmental Protection Agency's National Risk Management Research Laboratory in Cincinnati, Ohio. To evaluate the genotoxicity and identify the mutagens in the soil before and after the various treatments, fractionated extracts of five soils were bioassayed for mutagenic activity with a microsuspension modification of the Salmonella histidine reversion assay. Soils were extracted by sonication using dichloromethane (DCM). The five extracts were fractionated in triplicate (two for bioassay and one for chemical analysis) by reverse-phase high-performance liquid chromatography (HPLC) using hexane/DCM/methanol, and the fraction for bioassay were solvent-exchanged into dimethyl sulfoxide by nitrogen evaporation. Forty HPLC fractions for each sample were bioassayed in strain YG1041 with and without exogenous liver metabolic activation. As shown in a companion paper, the mutagenicity of two treatments (BS and BP) was significantly greater than the mutagenicity of the untreated soil. Mutagenic fractions (> 500 revertants) were analyzed by gas chromatography/mass spectrometry (GC/MS). PAH analysis of the soils indicated that all treatments were effective in reducing the total PAH concentration (48-74%). Qualitative GC/MS analysis of the mutagenic fractions from the BS and BP treatments indicated that they contained azaarenes, which are mutagens. The CMP and LT processes were the most effective and least toxic bioremediation procedures based on mutagenic potency and chemical analysis. This research demonstrated that the combination of bioassays and chemical analysis provided a more accurate determination of

  12. Toxicokinetics and critical body burden of fluoranthene in amphipod bioassays with Hyalella azteca and Diporeia sp.

    SciTech Connect

    Driscoll, S.K.; Landrum, P.

    1995-12-31

    Freshwater amphipods (Hyalella azteca and Diporeia sp.) were exposed to fluoranthene under yellow light in 10-day water-only and 30-day sediment bioassays. In water, the 10-d-LC50 for H. azteca (at 20 C) was 564 nmol/L (114 {micro}g/L). Survival of Diporeia (at 4 C) was higher, ranging from 87 to 97% at concentrations up to 1,285 nmol/L (260 {micro}g/L, the limit of water solubility). Although H. azteca was more sensitive than Diporeia to fluoranthene in water, it appeared to be less sensitive in sediment bioassays. Survival of H. azteca in sediment bioassays was generally greater than 90% at all doses, even after 30 d at the highest dose (136 nmol/gdw). A 10-d exposure of H. azteca to a sediment concentration (136 nmol/gdw) with an estimated interstitial water concentration (264 nmol/L), more than twice that of the water-only LC50 (114 nmol/L), resulted in only 5% mortality. In contrast, survival of Diporeia at the highest sediment dose (688 nmol/gdw) averaged 67%, 44%, and 16% after 10, 17 and 30-d exposures, respectively. Thus, although no substantial mortality was observed for Diporeia in water-only bioassays, sediment exposures resulted in significant dose dependent mortality. At the highest sediment doses, observed body burdens in Diporeia were in the range of 1--2 {micro}mol/gww, concentrations that would be expected to produce death by narcosis. In general, the body burden of H. azteca did not exceed 0.5 {micro}mol/gww in the sediment bioassay, which is consistent with the low mortality that was observed. Thus, measures of the actual dose in the organism best define the exposure. These results suggest that estimation of an interstitial water concentration may be insufficient for predicting sediment toxicity.

  13. Responses of lone star tick (acari: ixodidae) nymphs to the repellent deet applied in acetone and ethanol solutions in vitro bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Behavioral bioassays remain a standard tool in the discovery, development, and registration of repellents. Although tick repellent bioassays tend to be rather uncomplicated, several factors can influence their outcomes. Typically repellent bioassays use a solvent, such as acetone or ethanol, to disp...

  14. SERS as a bioassay platform: fundamentals, design, and applications

    SciTech Connect

    Porter, M.; Lipert, R.; Siperko, L.; Wang, G.; Narayanan, R.

    2008-03-18

    Bioanalytical science is experiencing a period of unprecedented growth. Drivers behind this growth include the need to detect markers central to human and veterinary diagnostics at ever-lower levels and greater speeds. A set of parallel arguments applies to pathogens with respect to bioterrorism prevention and food and water safety. This tutorial review outlines our recent explorations on the use of surface enhanced Raman scattering (SERS) for detection of proteins, viruses, and microorganisms in heterogeneous immunoassays. It will detail the design and fabrication of the assay platform, including the capture substrate and nanoparticle-based labels. The latter, which is the cornerstone of our strategy, relies on the construction of gold nanoparticles modified with both an intrinsically strong Raman scatterer and an antibody. This labelling motif, referred to as extrinsic Raman labels (ERLs), takes advantage of the well-established signal enhancement of scatterers when coated on nanometre-sized gold particles, whereas the antibody imparts antigenic specificity. We will also examine the role of plasmon coupling between the ERLs and capture substrate, and challenges related to particle stability, nonspecific adsorption, and assay speed.

  15. Contact Bioassays with Phenoxybenzyl and Tetrafluorobenzyl Pyrethroids against Target-Site and Metabolic Resistant Mosquitoes

    PubMed Central

    Horstmann, Sebastian; Sonneck, Rainer

    2016-01-01

    Background Mosquito strains that exhibit increased tolerance to the chemical class of compounds with a sodium channel modulator mode of action (pyrethroids and pyrethrins) are typically described as “pyrethroid resistant”. Resistance to pyrethroids is an increasingly important challenge in the control of mosquito-borne diseases, such as malaria or dengue, because one of the main interventions (the distribution of large numbers of long-lasting insecticide-treated bed nets) currently relies entirely on long-lasting pyrethroids. Increasing tolerance of target insects against this class of insecticides lowers their impact in vector control. The current study suggests that the level of metabolic resistance depends on the structure of the molecule and that structurally different compounds may still be effective because detoxifying enzymes are unable to bind to these uncommon structures. Methods Treated surface contact bioassays were performed on susceptible Aedes aegypti, East African knockdown resistance (kdr) Anopheles gambiae (strain RSP-H) and metabolically resistant Anopheles funestus (strain FUMOZ-R) with different pyrethroids, such as cypermethrin, ß-cyfluthrin, deltamethrin, permethrin and transfluthrin (alone and in combination with the synergist piperonyl butoxide). The nonfluorinated form of transfluthrin was also assessed as a single agent and in combination with piperonyl butoxide. Results Although the dosages for pyrethroids containing a phenoxybenzyl moiety have exhibited differences in terms of effectiveness among the three tested mosquito species, the structurally different transfluthrin with a polyfluorobenzyl moiety remained active in mosquitoes with upregulated P450 levels. In trials with transfluthrin mixed with piperonyl butoxide, the added synergist exhibited no efficacy-enhancing effect. Conclusion The results of this study suggest that transfluthrin has the potential to control P450-mediated metabolically resistant mosquitoes because the

  16. Bioassays for estrogenic activity: development and validation of estrogen receptor (ERalpha/ERbeta) and breast cancer proliferation bioassays to measure serum estrogenic activity in clinical studies.

    PubMed

    Li, J; Lee, L; Gong, Y; Shen, P; Wong, S P; Wise, Stephen D; Yong, E L

    2009-02-01

    Standard estrogenic prodrugs such as estradiol valerate (E2V) and increasingly popular phytoestrogen formulations are commonly prescribed to improve menopausal health. These drugs are metabolized to numerous bioactive compounds, known or unknown, which may exert combinatorial estrogenic effects in vivo. The aim of this study is to develop and validate estrogen receptor (ER) alpha/ERbeta reporter gene and MCF-7 breast cancer cell proliferation bioassays to quantify serum estrogenic activities in a clinical trial setting. We measured changes in serum estrogenicity following ingestion of E2V and compared this to mass spectrometric measurements of its bioactive metabolites, estrone and 17beta-stradiol. ERalpha bioactivity of the 192 serum samples correlated well (R = 79%) with 17beta-estradiol levels, and adding estrone improved R to 0.83 (likelihood ratio test, P < 0.0001), suggesting that the ERalpha assay reflects summated activity of compounds in serum. ERbeta correlated moderately (R = 0.52) with estrone and 17beta-estradiol, with an estrone/17beta-estradiol coefficient ratio that was twice that of ERalpha, indicating estrone was more active on a molar basis in the ERbeta assay. Unlike the ERalpha and ERbeta bioassays, MCF-7 cell proliferation was driven by 17beta-estradiol, and addition of estrone did not increase the predictive value of the model, suggesting that the driver or drivers for breast cancer cell proliferation were not the same as for ERalpha and ERbeta transactivation. In contrast, a decoction of the traditional Chinese medicinal herb Epimedium pubescens did not induce significant changes in estrogenic bioactivity over baseline. These data indicate that ERalpha/ERbeta reporter gene and MCF-7 breast cancer cell proliferation bioassays reflect different aspects of estrogenic activity and that these assays suggest that the Epimedium formulation tested is unlikely to exert significant estrogenic effects in humans.

  17. Applicability of toxicity bioassays to ecological risk assessment in arid and semiarid ecosystems.

    SciTech Connect

    Markwiese, J. T.; Ryti, R. T.; Hooten, M. M.; Michael, D. I.; Hlohowskyj, I.; Environmental Assessment; Neptune and Company, Inc.

    2001-01-01

    Substantial tracts of land in the southwestern and western U.S. are undergoing or will require ERA. Toxicity bioassays employed in baseline ERAs are, for the most part. representative of mesic systems, and highly standardized test species (e.g., lettuce, earthworm) are generally not relevant to arid system toxicity testing. Conversely, relevant test species are often poorly characterized with regard to toxicant sensitivity and culture conditions. The applicability of toxicity bioassays to ecological risk assessment in arid and semiarid ecosystems was reviewed for bacteria and fungi, plants, terrestrial invertebrates, and terrestrial vertebrates. Bacteria and fungi are critical to soil processes, and understanding their ecology is important to understanding the ecological relevance of bioassays targeting either group. Terrestrial bacteria require a water film around soil particles to be active, while soil fungi can remain active in extremely dry soils. It is therefore expected that fungi will be of greater importance to arid and semiarid systems (Whitford 1989). If microbial processes are to be measured in soils of arid environments, it is recommended that bioassays target fungi. Regardless of the taxa studied, problems are associated with the standardization and interpretability of microbial tests, and regulatory acceptance may hinder widespread incorporation of microbial toxicity bioassays in arid system risk assessments. Plant toxicity bioassays are gaining recognition as sensitive indicators of soil conditions because they can provide a cost-effective and relatively rapid assessment of soil quality for both pre- and postremediation efforts. Although the choices of suitable plant species for assessing mesic system soils are numerous, the choices for arid system soils are limited. Guidance is provided for evaluating plant species with regard to their suitability for serving as representative arid system flora. Terrestrial invertebrates can survive and flourish in

  18. Identification of biological agents using surface enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Paxon, Tracy L.; Duthie, R. Scott; Renko, Casey; Burns, Andrew A.; Lesaicherre, Marie L.; Mondello, Frank J.

    2011-05-01

    GE Global Research Center, in collaboration with Morpho Detection, Inc. has developed an assay scheme for the identification of biological agents using Surface Enhanced Raman Scattering (SERS). Specifically, unique spectroscopic signatures are generated using SERS tags consisting of individual glass-encapsulated gold nanoparticles and surfacebound reporter molecules. These SERS tags are modified with a capture moiety specific to the antigen of interest, and serve as a spectroscopic label in a bead-based sandwich assay. Assays are being developed for a variety of pathogens and this paper will focus on aspects of assay development, optimization, stabilization and validation. Results on the development of an assay to detect Ricin toxin will be presented, and preliminary feasibility studies for the detection of additional pathogens will be discussed.

  19. A reliable monitoring of the biocompatibility of an effluent along an oxidative pre-treatment by sequential bioassays and chemical analyses.

    PubMed

    Amat, A M; Arques, A; García-Ripoll, A; Santos-Juanes, L; Vicente, R; Oller, I; Maldonado, M I; Malato, S

    2009-02-01

    A new approach to assess biocompatibility of an effluent, based on combination of different bioassays and chemical analyses, has been tested using a mixture of four commercial pesticides treated by a solar photo-Fenton as target effluent. A very fast elimination of the pesticides occurred (all of them were below detection limit at t30W=36 min), but mineralisation was a more time-consuming process, due to the formation of organic intermediates and to the presence of solvents, as shown by GC-MS analysis. Measurements based on activated sludge indicated that detoxification was coincident with the removal of the active ingredients, while more sensitive Vibrio fischeri bacterium showed significant toxicity until the end of the experiment, although the effluent might be compatible with biological processes. Biodegradability of the solutions was enhanced by the photochemical process, to reach BOD5/COD ratios above 0.8. Longer time bioassays, such as the Zahn-Wellens' test, support the applicability of coupling photochemical with activated sludge-based biological processes to deal with these effluents.

  20. Toxicity bioassays for water from black-odor rivers in Wenzhou, China.

    PubMed

    DeFu, He; RuiRui, Chen; EnHui, Zhu; Na, Chen; Bo, Yang; HuaHong, Shi; MinSheng, Huang

    2015-02-01

    Following urbanization, a large number of urban rivers were contaminated and turned to black-odor rivers. The traditional approach for detecting water quality is based on chemical or physical analysis. However, biological toxicity of black-odor water has been less addressed. As two typical black-odor rivers, Jiushanwai River (JS) and Shanxia River (SX) are tributaries of Wen-Rui Tang River in Wenzhou (south of China). The eco-safety of the urban rivers was evaluated by bioassay for water toxicity in this study. Ten and 5 sampling sites were respectively set along JS and SX. Water samples were collected monthly from October 2010 to October 2011. The general physical and chemical parameters of river water were monitored. In order to investigate the ecotoxicological effects of black-odor water, the following bioassays were used: (1) Fish acute toxicity test (Danio rerio, comprehensive toxicity), (2) luminescent bacteria bioassay (Qinghaiensis vibrio, toxicity to bacteria), and (3) tropical claw embryo assay (Xenopus tropicalis, embryo toxicity). Biotoxicity of black-odor rivers water was demonstrated by D. rerio, Q. vibrio, and X. tropicalis embryos. Toxicological effects of black-odor water were respectively shown by mortality of zebrafish, and by the relative inhibitory light rate of luminescent bacteria. However, luminescent bacteria were more sensitive to inspect biotoxicity than zebrafish. In X. tropicalis embryos test, toxicological effects of black-odor water were mostly shown by embryos' survival rate and teratogenic rate. Bioassay results showed that toxicity of SX water was higher than that of JS water, especially in summer. Statistical analysis of luminescent bacteria toxicity test showed that biotoxicity of SX and JS was high in summer, but low in winter and spring. The seasonal changes of water toxicity of the black-odor river were positively correlative with changes of water temperature (p < 0.05), and related to pH and ammonium nitrogen of water

  1. The use of acute and chronic bioassays to determine the ecological risk and bioremediation efficiency of oil-polluted soils.

    PubMed

    van Gestel, C A; van der Waarde, J J; Derksen, J G; van der Hoek, E E; Veul, M F; Bouwens, S; Rusch, B; Kronenburg, R; Stokman, G N

    2001-07-01

    To compare the effectiveness of acute and chronic bioassays for the ecological risk assessment of polluted soils, soil samples from a site with an historical mineral oil contamination (< 50-3,300 mg oil/kg dry soil) at the Petroleum Harbour in Amsterdam, The Netherlands, were screened for ecological effects using acute and chronic bioassays. A two-step 0.001 M Ca(NO3)2 extraction at a final solution-to-soil ratio of 1:1 was used to prepare extracts for the acute bioassays. Acute bioassays (< or = 5 d) applied to the 0.001 M Ca(NO3)2 extracts from the polluted and reference soils included growth tests with bacteria (Bacillus sp.), algae (Raphidocelis subcapitata), and plants (Lactuca sativa), immobility tests with nematodes (Plectus acuminatus), springtails (Folsomia candida), and cladocerans (Daphnia magna), and the Microtox test (Vibrio fischeri). Chronic bioassays (four weeks) performed on the same soil samples included tests with L. sativa, F. candida, and earthworms (Eisenia fetida) and the bait-lamina test (substrate consumption). The acute bioassays on Microtox showed a response that corresponded with the level of oil pollution. All other acute bioassays did not show such a consistent response, probably because pollutant levels were too low to cause acute effects. All chronic bioassays showed sublethal responses according to the contaminant levels (oil and in some soils also metals). This shows that chronic bioassays on soil samples are more sensitive in assessing the toxicity of mineral oil contamination in soil than acute bioassays on soil extracts. A pilot scale bioremediation study on soils taken from the two most polluted sites and a control site showed a rapid decline of oil concentrations to reach a stable level within eight weeks. Acute bioassays applied to the soils, using Microtox, algae, and D. magna, and chronic bioassays, using plants, Collembola, earthworms, and bait-lamina consumption, in all cases showed a rapid reduction of toxicity, which

  2. [Investigation on pattern of quality control for Chinese materia medica based on famous-region drug and bioassay--the work reference].

    PubMed

    Yan, Dan; Xiao, Xiaohe

    2011-05-01

    Selection and standardization of the work reference are the technical issues to be faced with in the bioassay of Chinese materia medica. Taking the bioassay of Coptis chinensis. as an example, the manufacture process of the famous-region drugs extraction was explained from the aspects of original identification, routine examination, component analysis and bioassay. The common technologies were extracted, and the selection and standardization procedures of the work reference for the bioassay of Chinese materia medica were drawn up, so as to provide technical support for constructing a new mode and method of the quality control of Chinese materia medica based on the famous-region drugs and bioassay.

  3. Magnetic Bead Based Immunoassay for Autonomous Detection of Toxins

    SciTech Connect

    Kwon, Y; Hara, C A; Knize, M G; Hwang, M H; Venkatesteswaran, K S; Wheeler, E K; Bell, P M; Renzi, R F; Fruetel, J A; Bailey, C G

    2008-05-01

    As a step towards toward the development of a rapid, reliable analyzer for bioagents in the environment, we are developing an automated system for the simultaneous detection of a group of select agents and toxins. To detect toxins, we modified and automated an antibody-based approach previously developed for manual medical diagnostics that uses fluorescent eTag{trademark} reporter molecules and is suitable for highly multiplexed assays. Detection is based on two antibodies binding simultaneously to a single antigen, one of which is labeled with biotin while the other is conjugated to a fluorescent eTag{trademark} through a cleavable linkage. Aqueous samples are incubated with the mixture of antibodies along with streptavidin-coated magnetic beads coupled to a photo-activatable porphyrin complex. In the presence of antigen, a molecular complex is formed where the cleavable linkage is held in proximity to the photoactivable group. Upon excitation at 680 nm, free radicals are generated, which diffuse and cleave the linkage, releasing the eTags{trademark}. Released eTags{trademark} are analyzed using capillary gel electrophoresis with laser-induced fluorescence detection. Limits of detection for ovalbumin and botulinum toxoid individually were 4 ng/mL (or 80 pg) and 16 ng/mL (or 320 pg), respectively, using the manual assay. In addition, we demonstrated the use of pairs of antibodies from different sources in a single assay to decrease the rate of false positives. Automation of the assay was demonstrated on a flow-through format with higher LODs of 125 ng/mL (or 2.5 ng) each of a mixture of ovalbumin and botulinum toxoid. This versatile assay can be easily modified with the appropriate antibodies to detect a wide range of toxins and other proteins.

  4. Magnetic bead based immunoassay for autonomous detection of toxins.

    PubMed

    Kwon, Youngeun; Hara, Christine A; Knize, Mark G; Hwang, Mona H; Venkateswaran, Kodumudi S; Wheeler, Elizabeth K; Bell, Perry M; Renzi, Ronald F; Fruetel, Julie A; Bailey, Christopher G

    2008-11-15

    We are developing an automated system for the simultaneous, rapid detection of a group of select agents and toxins in the environment. To detect toxins, we modified and automated an antibody-based approach previously developed for manual medical diagnostics that uses fluorescent eTag reporter molecules and is suitable for highly multiplexed assays. Detection is based on two antibodies binding simultaneously to a single antigen, one of which is labeled with biotin while the other is conjugated to a fluorescent eTag through a cleavable linkage. Aqueous samples are incubated with the mixture of antibodies along with streptavidin-coated magnetic beads and a photoactive porphyrin complex. In the presence of antigen, a molecular complex is formed where the cleavable linkage is held in proximity to the photoactive group. Upon excitation at 680 nm, free radicals are generated, which diffuse and cleave the linkage, releasing the eTags. Released eTags are analyzed using capillary gel electrophoresis with laser-induced fluorescence detection. Limits of detection for ovalbumin and botulinum toxoid individually were 4 (or 80 pg) and 16 ng/mL (or 320 pg), respectively, using the manual assay. In addition, we demonstrated the use of pairs of antibodies from different sources in a single assay to decrease the rate of false positives. Automation of the assay was demonstrated in a flow-through format with higher LODs of 32 ng/mL (or 640 ng) each of a mixture of ovalbumin and botulinum toxoid. This versatile assay can be easily modified with the appropriate antibodies to detect a wide range of toxins and other proteins.

  5. Environmental effects of dredging: Wetland animal bioassays/biomonitoring. Technical note

    SciTech Connect

    Simmers, J.W.; Kay, S.H.; Rhett, R.G.; Lee, C.R.

    1987-03-01

    This note follows Technical Note EEDP-O3-1 and adds support to the concept of using wetland animals as Indicators of bioavailable contaminants in dredged material used to create intertidal wetlands. The text of this tech note was taken from a paper by Kay, Marquenie, and Simmers (1986). Animal bioassay test procedures are being evaluated (field tested) and verified under the Interagency Field Verification of Testing and Predictive Methodologies for Dredged Material Disposal Alternatives in the Field Verification Program (FVP). Bioassays have been shown to be a relatively simple tool for ecological evaluation and environmental assessment of potential contaminant movement within permanent or temporary wetlands, and with field verification, it will be a useful biomonitoring tool as well.

  6. Lung tumors in strain A mice as a bioassay for carcinogenicity of environmental chemicals

    SciTech Connect

    Stoner, G.D. )

    1991-03-01

    This report describes the protocol for the strain A mouse lung tumor bioassay and summarizes results on selected chemicals that have been tested for carcinogenicity in the assay. The assay is of 6 months duration and can distinguish 2-fold differences in carcinogenic potential of compounds from several chemical classes. Specifically, the assay is sensitive to polycyclic hydrocarbons, nitrosamines and nitrosoureas, carbamates, aflatoxin, certain metals, hydrazines, and others, but is relatively insensitive to aromatic amines, aliphatic halides, and other compounds that are carcinogenic in the rodent liver and/or bladder. Recommendations are made for future studies on the: (1) distribution and metabolism of chemicals in strain A mouse lung tissue and in specific lung cell types; (2) ability of the lung tumor bioassay to detect inhibitors and promoters of carcinogenesis; and (3) use of the assay for testing mixtures of chemicals for carcinogenic activity.

  7. Biomagnification of bioassay derived 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents

    USGS Publications Warehouse

    Jones, P.D.; Ankley, G.T.; Best, D. A.; Crawford, R.; DeGalan, N.; Giesy, J.P.; Kubiak, T.J.; Ludwig, J. P.; Newsted, J.L.; Tillitt, D. E.; Verbrugge, D.A.

    1993-01-01

    In recent years contamination of the Great Lakes ecosystem with planar chlorinated hydrocarbons (PCHs) has attracted considerable concern due to their known reproductive and teratogenic effects. The H4IIE bioassay has been standardized as a means of measuring the biological potency of a PCH mixture as 2,3,7,8-tetrachloro-p-dibenzodioxin equivalents (TCDD-EQ). Using this bioassay we have investigated the biomagnification of TCDD-EQ in a semi-closed ecosystem. The biomagnification of TCDD-EQ is demonstrated and results indicate that the food chain is the major pathway for TCDD-EQ through this ecosystem. The H4IIE assay system is demonstrated to be a viable integrative measure of the total concentration of TCDD-EQ in different trophic levels.

  8. Comparison of laboratory and in situ sediment bioassays using Corophium volutator.

    PubMed

    Kater, B J; Postma, J F; Dubbeldam, M; Prins, J T

    2001-06-01

    Bioassays with the marine amphipod Corophium volutator were performed simultaneously in situ and in the laboratory using sediments sampled from the in situ locations. In most cases, the in situ response was significantly higher compared to the laboratory response. This difference was not caused by direct influence of the use of the field chamber on Corophium sp., nor was the difference caused by the overlying water used. Experiments showed homogenization can affect the toxicity of a sediment, but not in such a way that it can completely explain the difference between the response in situ and in the laboratory. Possible explanatory factors are harbor activity, storms, and temperature. To reduce the influence of some of these factors, the best period of the year to perform in situ bioassays with C. volutator is May, June, or September.

  9. Inkjet-printed bioassays for direct reading with a multimode DVD/Blu-Ray optical drive.

    PubMed

    Li, Xiaochun; Shi, Maolin; Cui, Caie; Yu, Hua-Zhong

    2014-09-16

    Compact disc-based bioassays have been developed as novel point-of-care (POC) tools for various applications in chemical analysis and biomedical diagnosis. For the fabrication of assay discs, the surface patterning and sample introduction have been restricted to manual delivery that is unfavorable for on-demand high throughput medical screening. Herein, we have adapted a conventional inkjet printer to prepare bioassays on regular DVD-Rs and accomplished quantitative analysis with a multimode DVD/Blu-Ray optical drive in conjunction with free disc diagnostic software. The feasibility and accuracy of this method have been demonstrated by the quantitative analysis of inkjet-printed biotin-streptavidin binding assays on DVD, which serves as a trial system for other complex, medically relevant sandwich-format or competitive immunoassays.

  10. Simultaneous bioassays in a microfluidic channel on plugs of different magnetic particles.

    PubMed

    Bronzeau, Sandrine; Pamme, Nicole

    2008-02-18

    Magnetic particles coated with specific biomolecules are often used as solid supports for bioassays but conventional test tube based techniques are time consuming and labour intensive. An alternative is to work on magnetic particle plugs immobilised inside microfluidic channels. Most research so far has focussed on immobilising one type of particle to perform one type of assay. Here we demonstrate how several assays can be performed simultaneously by flushing a sample solution over several plugs of magnetic particles with different surface coatings. Within a microchannel, three plugs of magnetic particles were immobilised with external magnets. The particles featured surface coatings of glycine, streptavidin and protein A, respectively. Reagents were then flushed through the three plugs. Molecular binding occurred between matching antigens and antibodies in continuous flow and was detected by fluorescence. This first demonstration opens the door to a quicker and easier technique for simultaneous bioassays using magnetic particles.

  11. Moment Selective Digital Detection of Single Magnetic Beads for Multiplexed Bioassays

    NASA Astrophysics Data System (ADS)

    Llandro, J.; Hayward, T. J.; Bland, J. A. C.; Morecroft, D.; Castaño, F. J.; Colin, I. A.; Ross, C. A.

    2008-06-01

    Research into lab-on-a-chip multiplexed bioassays has focused on libraries of biochemical probes, indexed by optically encoded micron-sized labels. However, few current methods have reconciled large multiplexing capability with a rapid detection system amenable to miniaturization. Magnetic identification of labels provides a strong candidate solution to this problem, yet no proposed single-label magnetic detection system can both read and encode magnetic labels. We present a magnetic multiplexed assay in lab-on-a-chip format which identifies target biomolecules from the hybridization results by reading encoded magnetic beads. We show that a microfabricated magnetoresistive ring-shaped sensor can read the magnetic moments of individual commercially available paramagnetic beads using an active digital technique. This work provides proof of principle for a new approach to magnetic labeling of biomolecules for high-throughput bioassays.

  12. Effect of disinfection upon dissolved organic carbon (DOC) in wastewater: bacterial bioassays.

    PubMed

    Arana, I; Santorum, P; Muela, A; Barcina, I

    2000-08-01

    Quantitative and qualitative changes in organic matter content of wastewater effluents attributable to chlorination and ozonation have been analysed using bioassays as well as organic carbon direct measures. Bioassays were carried out using the bacterial populations of wastewater and two Escherichia coli strains as test micro-organisms. Our results indicate that pure strains present some advantages over indigenous bacteria. Although wastewater bacterial populations are better adapted to growth in wastewater, E. coli strains are more sensitive to changes in dissolved organic carbon (DOC) content. Moreover, the use of pure cultures allows estimation of the portion of DOC which can be converted in cell biomass, the assimilable organic carbon (AOC). Finally, the results obtained using prototrophic and the auxotrophic strains of E. coli suggested that ozonation alters the amino acid composition of wastewater while chlorination does not change the quantity nor the quality of the DOC present in effluents.

  13. Genotoxic evaluation of an industrial effluent from an oil refinery using plant and animal bioassays

    PubMed Central

    2010-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are genotoxic chemicals commonly found in effluents from oil refineries. Bioassays using plants and cells cultures can be employed for assessing environmental safety and potential genotoxicity. In this study, the genotoxic potential of an oil refinery effluent was analyzed by means of micronucleus (MN) testing of Alium cepa, which revealed no effect after 24 h of treatment. On the other hand, primary lesions in the DNA of rat (Rattus norvegicus) hepatoma cells (HTC) were observed through comet assaying after only 2 h of exposure. On considering the capacity to detect DNA damage of a different nature and of these cells to metabolize xenobiotics, we suggest the association of the two bioassays with these cell types, plant (Allium cepa) and mammal (HTC) cells, for more accurately assessing genotoxicity in environmental samples. PMID:21637622

  14. Regional differences in stratum corneum reactivity to surfactants. Quantitative assessment using the corneosurfametry bioassay.

    PubMed

    Henry, F; Goffin, V; Maibach, H I; Piérard, G E

    1997-12-01

    The skin does not react similarly to the presence of xenobiotics over all anatomic sites. Distinct regional differences have been described for irritancy and percutaneous absorption. The present study assesses the regional variation of stratum corneum reactivity to surfactants using the corneosurfametry bioassay. Stratum corneum was harvested from 6 body sites in 20 young adults. Corneosurfametry was performed using water, 1% SLS and a 5% soap solution. Data show that the best variable to assess regional variability in irritancy is the overall difference in corneosurfametry (ODC), comparing the effect of a given surfactant with water. The dorsal hand and volar forearm were the least reactive, the neck, forehead, back and dorsal foot the most reactive, sites. It is concluded that the corneosurfametry bioassay, through the ODC variable, is a practically noninvasive tool for the evaluation of regional variation in irritancy at the level of the stratum corneum.

  15. Detection of Toxoplasma gondii by PCR and Mouse Bioassay in Rodents of Ahvaz District, Southwestern Iran

    PubMed Central

    Saki, J.; Khademvatan, S.

    2014-01-01

    Toxoplasma gondii is obligate coccidian zoonotic parasite. Felidae family is definitive and wide ranges of warm-blooded vertebrates are intermediate hosts for the parasite. Rodents are measured as an important source of T. gondii infection for the definitive host. Thus, this study aimed to investigate Toxoplasm infection in rodents of Ahvaz district, southwest of Iran. A total of 100 rodents (73 Rattus norvegicus, 21 Rattus rattus, and 6 Mus musculus) were collected and studied by GRA6PCR and mouse bioassay. The finding indicated that 6 out of 100 (6%) and 2 out of 100 (2%) samples were positive by PCR and mouse bioassay, respectively. The results show notable chronic infection in the rodent and potential transmission of the infection among animal and men in the region. Accordingly, this study recommended investigating of the T. gondii infection in definitive and other intermediate hosts in other points of Khuzestan province, Southwest, Iran. PMID:24605327

  16. Comparison of cancer risks projected from animal bioassays to epidemiologic studies of acrylonitrile-exposed workers.

    PubMed

    Ward, C E; Starr, T B

    1993-10-01

    Bioassay findings have demonstrated that acrylonitrile (ACN) is a rodent carcinogen, but the available epidemiologic evidence provides little support for the human carcinogenicity of ACN. This discordance between laboratory animal and human study findings is explored by determining post hoc the statistical power of 11 epidemiologic studies of ACN-exposed workers to detect the all-site and brain cancer excesses that are projected from rodent drinking water bioassay data. At reasonable estimates of the level and duration of exposures among the occupational cohorts, a majority of the human studies had sufficient power (> 80%) to detect the projected excesses, yet such responses were consistently absent. We conclude, subject to certain caveats, that the upper bound estimate of ACN's inhalation cancer potency of 1.5 x 10(-4) per ppm is too high to be consistent with the human ACN experience.

  17. Evaluation of brine shrimp (Artemia salina) larvae as a bioassay for mycotoxins in animal feedstuffs.

    PubMed Central

    Prior, M G

    1979-01-01

    Brine shrimp larvae was tested as a possible simple biological screening system to identify specimens of animal feedstuffs that should be examined further by chemical analytical procedures for mycotoxins. All extracts of the control, nonmouldy feedstuffs increased larval mortality, this being most marked in the case of silage. Chemical and biological testing of diagnostic specimens indicated that the bioassay identified two of four chemically positive specimens and 59 of 135 chemically negative specimens and 59 identified larvicidal compounds present in normal feedstuffs gave a high percentage (56%) of false-positive bioassay results when compared to the results of chemical analyses for three mycotoxins. The use of brine shrimp larvae did not materially reduce the necessity of conducting chemical analyses for mycotoxins. PMID:548157

  18. Characterizing the genotoxicity of hazardous industrial wastes and effluents using short-term bioassays

    SciTech Connect

    Houk, V.S.; DeMarini, D.M.

    1989-01-01

    This paper demonstrates that short-term bioassays can reliably and expeditiously measure the genotoxic potential of hazardous industrial wastes and effluents. Petrochemical wastes have been studied in detail, especially discharges from chemical manufacturing plants and textile and dye effluents. However, there is little information on effluents from pesticide manufacturers. The most extensive evaluations have been conducted on effluents from pulp and paper mills. These studies have shown which pulping plants generate the most genotoxic effluents, which process wastes are most hazardous, have isolated and identified the compounds responsible for the genotoxic activity, have described the environmental fate of these compounds, have evaluated the types of genetic damage likely to occur upon exposure to the effluents, and have identified several treatment methods that effectively reduce the genotoxicity of the effluents. The coupling of bioassays for biological analysis with chemical evaluation provides the most powerful approach to assessing the overall health effects of complex industrial wastes and effluents.

  19. Evaluation of mouse bioassay results in an inter-laboratory comparison for paralytic shellfish poisoning toxins

    NASA Astrophysics Data System (ADS)

    Cao, Jijuan; Zheng, Jiang; Yu, Bing; Wang, Qiuyan; Xu, Junyi; Li, Aifeng

    2011-07-01

    An inter-laboratory comparison of the AOAC mouse bioassay for paralytic shellfish poisoning (PSP) toxicity in shellfish was carried out among 25 Chinese laboratories to examine the overall performance for PSP testing in China, and to analyze the main factors affecting the performance of this method. The toxic scallop Patinopecten yessoensis collected from coast of Bohai Sea, China, was used as a test sample in the comparison study. The results were reported and evaluated using robust statistical methods. The z scores showed that 80%, 8%, and 12% of laboratories reported satisfactory results, unsatisfactory results, and questionable results, respectively. This evaluation demonstrates that the PSP mouse bioassay is an appropriate method for screening and testing PSP toxicity in shellfish. However, it was found that the experience and skill of technicians, as well as the body weight and health status of mice being used significantly affected the accuracy of the method.

  20. Carcinogenicity bioassays of vinyl chloride monomer: a model of risk assessment on an experimental basis.

    PubMed Central

    Maltoni, C; Lefemine, G; Ciliberti, A; Cotti, G; Carretti, D

    1981-01-01

    Data are presented regarding the final results of the Bentivoglio (Bologna) project on long-term carcinogenicity bioassays of vinyl chloride (VC). The experimental project studied the effects of the monomer, administered by different routes, concentrations and schedules of treatment, to animals (near 7000) of different species, strains, sex and age. To our knowledge this is the largest experimental carcinogenicity study performed on a single compound by a single institution. The results indicate that VC is a multipotential carcinogen, affecting a variety of organs and tissues. In the experimental conditions studied, the neoplastic effects of the monomer were also detected at low doses. The experimental and biological factors greatly affect the neoplastic response to VC. Long-term carcinogenicity bioassays are, at present, a unique tool for the identification and quantification of environmental and occupational risks. Precise and highly standardized experimental procedures are needed to obtain data for risk assessment. PMID:6800782

  1. A macroalgal germling bioassay to assess biocide concentrations in marine waters.

    PubMed

    Girling, J A; Thomas, K V; Brooks, S J; Smith, D J; Shahsavari, E; Ball, A S

    2015-02-15

    A bioassay method using the early life stages (germlings) of macroalgae was developed to detect toxicity of anti-fouling paint biocides. A laboratory based bioassay using Ulva intestinalis and Fucus spiralis germlings was performed with 4 common anti-fouling biocides (tributyltin (TBT), Irgarol 1051, Diuron and zinc sulphate), over a range of environmentally relevant concentrations (0.0033-10 μg l(-1)). Comparison between the two species showed that germlings of U. intestinalis were better adapted for in-situ monitoring, as germlings of F. spiralis appeared to be too robust to display sufficient growth differences. The response of U. intestinalis germling growth appeared to reflect environmental biocide concentrations. Overall the developed method showed potential for the assessment of the sub-lethal effects of anti-fouling biocides on the early developmental stages of U. intestinalis.

  2. Bioassays with terrestrial and aquatic species as monitoring tools of hydrocarbon degradation.

    PubMed

    Bori, Jaume; Vallès, Bettina; Ortega, Lina; Riva, Maria Carme

    2016-09-01

    In this study chemical analyses and ecotoxicity tests were applied for the assessment of a heavily hydrocarbon-contaminated soil prior and after the application of a remediation procedure that consisted in the stimulation of soil autochthonous populations of hydrocarbon degraders in static-ventilated biopiles. Terrestrial bioassays were applied in mixtures of test soils and artificial control soil and studied the survival and reproduction of Eisenia fetida and the avoidance response of E. fetida and Folsomia candida. Effects on aquatic organisms were studied by means of acute tests with Vibrio fischeri, Raphidocelis subcapitata, and Daphnia magna performed on aqueous elutriates from test soils. The bioremediation procedure led to a significant reduction in the concentration of hydrocarbons (from 34264 to 3074 mg kg(-1), i.e., 91 % decrease) and toxicity although bioassays were not able to report a percentage decrease of toxicity as high as the percentage reduction. Sublethal tests proved the most sensitive terrestrial bioassays and avoidance tests with earthworms and springtails showed potential as monitoring tools of hydrocarbon remediation due to their high sensitivity and short duration. The concentrations of hydrocarbons in water extracts from test soils were 130 and 100 μg L(-1) before and after remediation, respectively. Similarly to terrestrial tests, most aquatic bioassays detected a significant reduction in toxicity, which was almost negligible at the end of the treatment. D. magna survival was the most affected by soil elutriates although toxicity to the crustacean was associated to the salinity of the samples rather than to the concentration of hydrocarbons. Ecotoxicity tests with aqueous soil elutriates proved less relevant in the assessment of hydrocarbon-contaminated soils due to the low hydrosolubility of hydrocarbons and the influence of the physicochemical parameters of the aquatic medium.

  3. Effects of Tributyltin Antifouling Paint Leachates on Pearl Harbor Organisms. Site-Specific Flowthrough Bioassay Tests.

    DTIC Science & Technology

    1985-12-01

    Organotin paint leachate. antifoulitip coa~tings. marine n~ii r, isms.A.benthicFIEL GRUP SB GOUP organisms. harbor pollutani fributt Iti omplx cmmuitie...of organotins should be closely monitored for ossible shifts in dominance of specific organisms- ~ 20 DISTRIBUJTION, AVAILABIUITY OF ABSTRACT 21...d* J 77. EXECUTIVE SUMMARY Site-specific bioassay tests were performed to determine the effects of organotin paint leachate on complex communities of

  4. Ultrasensitive microarray bioassays using cyanine5 dye-doped silica nanoparticles

    NASA Astrophysics Data System (ADS)

    Flynn, S. P.; Kelleher, S. M.; Acorn, J. N.; Kurzbuch, D.; Daniels, S.; McDonagh, C.; Clancy, E.; Smith, T. J.; Nooney, R.

    2016-11-01

    Herein we report the use of high brightness Cyanine5-doped silica nanoparticles (NPs) for the detection of antibodies or DNA in microarray bioassays. NP labels showed negligible non-specific binding, greater sensitivity and lower limits of detection when compared to free dye-labelled biomolecules. Moreover, the spotted microarrays used in this study required low NP and antibody concentrations to generate large data sets with improved statistical accuracy. These NPs have significant potential for use in biosensing for disease detection.

  5. Translation-dependent bioassay for amino acid quantification using auxotrophic microbes as biocatalysts of protein synthesis.

    PubMed

    Kameya, Masafumi; Asano, Yasuhisa

    2017-03-01

    Bioassay for amino acid quantification is an important technology for a variety of fields, which allows for easy, inexpensive, and high-throughput analyses. Here, we describe a novel translation-dependent bioassay for the quantification of amino acids. For this, the gene encoding firefly luciferase was introduced into Lactococcus lactis auxotrophic to Glu, His, Ile, Leu, Pro, Val, and Arg. After a preculture where luciferase expression was repressed, the cells were mixed with analytes, synthetic medium, and an inducer for luciferase expression. Luminescence response to the target amino acid appeared just after mixing, and linear standard curves for these amino acids were obtained during 15-60-min incubation periods. The rapid quantification of amino acids has neither been reported in previous works on bioassays nor is it theoretically feasible with conventional methods, which require incubation times of more than 4 h to allow for the growth of the microbe used. In contrast, our assay was shown to depend on protein translation, rather than on cell growth. Furthermore, replacement of the luciferase gene with that of the green fluorescent protein (GFP) or β-galactosidase allowed for fluorescent and colorimetric detection of the amino acids, respectively. Significantly, when a Gln-auxotrophic Escherichia coli mutant was created and transformed by a luciferase expression plasmid, a linear standard curve for Gln was observed in 15 min. These results demonstrate that this methodology can provide versatile bioassays by adopting various combinations of marker genes and host strains according to the analytes and experimental circumstances.

  6. Zebrafish (Danio rerio) bioassay for visceral toxicosis of catfish and botulinum neurotoxin serotype E.

    PubMed

    Chatla, Kamalakar; Gaunt, Patricia; Petrie-Hanson, Lora; Hohn, Claudia; Ford, Lorelei; Hanson, Larry

    2014-03-01

    Visceral toxicosis of catfish (VTC), a sporadic disease of cultured channel catfish (Ictalurus punctatus) often with high mortality, is caused by botulinum neurotoxin serotype E (BoNT/E). Presumptive diagnosis of VTC is based on characteristic clinical signs and lesions, and the production of these signs and mortality after sera from affected fish is administered to sentinel catfish. The diagnosis is confirmed if the toxicity is neutralized with BoNT/E antitoxin. Because small catfish are often unavailable, the utility of adult zebrafish (Danio rerio) was evaluated in BoNT/E and VTC bioassays. Channel catfish and zebrafish susceptibilities were compared using trypsin-activated BoNT/E in a 96-hr trial by intracoelomically administering 0, 1.87, 3.7, 7.5, 15, or 30 pg of toxin per gram of body weight (g-bw) of fish. All of the zebrafish died at the 7.5 pg/g-bw and higher, while the catfish died at the 15 pg/g-bw dose and higher. To test the bioassay, sera from VTC-affected fish or control sera were intracoelomically injected at a dose of 10 µl per zebrafish and 20 µl/g-bw for channel catfish. At 96 hr post-injection, 78% of the zebrafish and 50% of the catfish receiving VTC sera died, while no control fish died. When the VTC sera were preincubated with BoNT/E antitoxin, they became nontoxic to zebrafish. Histology of zebrafish injected with either VTC serum or BoNT/E demonstrated renal necrosis. Normal catfish serum was toxic to larval zebrafish in immersion exposures, abrogating their utility in VTC bioassays. The results demonstrate bioassays using adult zebrafish for detecting BoNT/E and VTC are sensitive and practical.

  7. The application of bioassays as indicators of petroleum-contaminated soil remediation.

    PubMed

    Płaza, Grazyna; Nałecz-Jawecki, Grzegorz; Ulfig, Krzysztof; Brigmon, Robin L

    2005-04-01

    Bioremediation has proven successful in numerous applications to petroleum contaminated soils. However, questions remain as to the efficiency of bioremediation in lowering long-term soil toxicity. In the present study, the bioassays Spirotox, Microtox, Ostracodtoxkit F, umu-test with S-9 activation, and plant assays were applied, and compared to evaluate bioremediation processes in heavily petroleum contaminated soils. Six higher plant species (Secale cereale L., Lactuca sativa L., Zea mays L., Lepidium sativum L., Triticum vulgare L., Brassica oleracea L.) were used for bioassay tests based on seed germination and root elongation. The ecotoxicological analyses were made in DMSO/H2O and DCM/DMSO soil extracts. Soils were tested from two biopiles at the Czechowice oil refinery, Poland, that have been subjected to different bioremediation applications. In biopile 1 the active or engineered bioremediation process lasted four years, while biopile 2 was treated passively or non-engineered for eight months. The test species demonstrated varying sensitivity to soils from both biopiles. The effects on test organisms exposed to biopile 2 soils were several times higher compared to those in biopile 1 soils, which correlated with the soil contaminants concentration. Soil hydrocarbon concentrations indeed decreased an average of 81% in biopile 1, whereas in biopile 2 TPH/TPOC concentrations only decreased by 30% after eight months of bioremediation. The bioassays were presented to be sensitive indicators of soil quality and can be used to evaluate the quality of bioremediated soil. The study encourages the need to combine the bioassays with chemical monitoring for evaluation of the bioremediation effectiveness and assessing of the contaminated/remediated soils.

  8. Fluorescence-Based Bioassays for the Detection and Evaluation of Food Materials

    PubMed Central

    Nishi, Kentaro; Isobe, Shin-Ichiro; Zhu, Yun; Kiyama, Ryoiti

    2015-01-01

    We summarize here the recent progress in fluorescence-based bioassays for the detection and evaluation of food materials by focusing on fluorescent dyes used in bioassays and applications of these assays for food safety, quality and efficacy. Fluorescent dyes have been used in various bioassays, such as biosensing, cell assay, energy transfer-based assay, probing, protein/immunological assay and microarray/biochip assay. Among the arrays used in microarray/biochip assay, fluorescence-based microarrays/biochips, such as antibody/protein microarrays, bead/suspension arrays, capillary/sensor arrays, DNA microarrays/polymerase chain reaction (PCR)-based arrays, glycan/lectin arrays, immunoassay/enzyme-linked immunosorbent assay (ELISA)-based arrays, microfluidic chips and tissue arrays, have been developed and used for the assessment of allergy/poisoning/toxicity, contamination and efficacy/mechanism, and quality control/safety. DNA microarray assays have been used widely for food safety and quality as well as searches for active components. DNA microarray-based gene expression profiling may be useful for such purposes due to its advantages in the evaluation of pathway-based intracellular signaling in response to food materials. PMID:26473869

  9. Bioassay for nisin in milk, processed cheese, salad dressings, canned tomatoes, and liquid egg products.

    PubMed

    Hakovirta, J; Reunanen, J; Saris, P E J

    2006-02-01

    A sensitive nisin quantification bioassay was constructed, based on Lactococcus lactis chromosomally encoding the nisin regulatory proteins NisK and NisR and a plasmid with a green fluorescent protein (GFP) variant gfp(uv) gene under the control of the nisin-inducible nisA promoter. This strain, LAC275, was capable of transducing the signal from extracellular nisin into measurable GFPuv fluorescence through the NisRK signal transduction system. The LAC275 cells detected nisin concentrations of 10 pg/ml in culture supernatant, 0.2 ng/ml in milk, 3.6 ng/g in processed cheese, 1 ng/g in salad dressings and crushed, canned tomatoes, and 2 ng/g in liquid egg. This method was up to 1,000 times more sensitive than a previously described GFP-based nisin bioassay. This new assay made it possible to detect significantly smaller amounts of nisin than the presently most sensitive published nisin bioassay based on nisin-induced bioluminescence. The major advantage of this sensitivity was that foods could be extensively diluted prior to the assay, avoiding potential inhibitory and interfering substances present in most food products.

  10. Toxicological profiling of sediments using in vitro bioassays, with emphasis on endocrine disruption.

    PubMed

    Houtman, Corine J; Cenijn, Peter H; Hamers, Timo; Lamoree, Marja H; Legler, Juliette; Murk, Albertinka J; Brouwer, Abraham

    2004-01-01

    In vitro bioassays are valuable tools for screening environmental samples for the presence of bioactive (e.g., endocrine-disrupting) compounds. They can be used to direct chemical analysis of active compounds in toxicity identification and evaluation (TIE) approaches. In the present study, five in vitro bioassays were used to profile toxic potencies in sediments, with emphasis on endocrine disruption. Nonpolar total and acid-treated stable extracts of sediments from 15 locations in the Rhine Meuse estuary area in The Netherlands were assessed. Dioxin-like and estrogenic activities (using dioxin-responsive chemical-activated luciferase gene expression [DR-CALUX] and estrogen-responsive chemical-activated luciferase gene expression [ER-CALUX] assays) as well as genotoxicity (UMU test) and nonspecific toxic potency (Vibrio fischeri assay) were observed in sediment extracts. For the first time, to our knowledge, in vitro displacement of thyroid hormone thyroxine (T4) from the thyroid hormone transport protein thransthyretin by sediment extracts was observed, indicating the presence of compounds potentially able to disrupt T4 plasma transport processes. Antiestrogenic activity was also observed in sediment. The present study showed the occurrence of endocrine-disrupting potencies in sediments from the Dutch delta and the suitability of the ER- and DR-CALUX bioassays to direct endocrine-disruption TIE studies.

  11. Sample preparation for combined chemical analysis and in vitro bioassay application in water quality assessment.

    PubMed

    Kolkman, Annemieke; Schriks, Merijn; Brand, Walter; Bäuerlein, Patrick S; van der Kooi, Margaretha M E; van Doorn, René H; Emke, Erik; Reus, Astrid A; van der Linden, Sander C; de Voogt, Pim; Heringa, Minne B

    2013-11-01

    The combination of in vitro bioassays and chemical screening can provide a powerful toolbox to determine biologically relevant compounds in water extracts. In this study, a sample preparation method is evaluated for the suitability for both chemical analysis and in vitro bioassays. A set of 39 chemicals were spiked to surface water, which were extracted using Oasis MCX cartridges. The extracts were chemically analyzed by liquid chromatography linear ion trap Orbitrap analysis and recoveries appeared to be on average 61% Compounds with logK(ow) values in the range between 0 and 4 are recovered well using this method. In a next step, the same extracts were tested for genotoxic activity using the Comet assay and Ames fluctuation test and for specific endocrine receptor activation using a panel of CALUX assays, for estrogenic (ER), androgenic (AR), glucocorticoid (GR), progestagenic (PR), and thyroidogenic (TR) agonistic activities. The results of the genotoxicity assays indicated that spiked genotoxic compounds were preserved during sample preparation. The measured responses of the GR CALUX and ER CALUX assays were similar to the predicted responses. The measured responses in the AR CALUX and PR CALUX assays were much lower than expected from the analytical concentration, probably due to antagonistic effects of some spiked compounds. Overall, the presented sample preparation method seems to be suitable for both chemical analysis and specific in vitro bioassay applications.

  12. Predicting water toxicity: pairing passive sampling with bioassays on the Great Barrier Reef.

    PubMed

    Shaw, Melanie; Negri, Andrew; Fabricius, Katharina; Mueller, Jochen F

    2009-11-08

    Many coral reefs worldwide occur adjacent to urban or agricultural land which places these ecosystems at threat of exposure to complex mixtures of pollutants. In this study, the pairing of passive sampler extracts with bioassays is proposed as a tool for predicting effects of organic pollutant mixtures on key biota within coral reef ecosystems. Passive samplers, SDB-RPS Empore disks, which sequester a mixture of the contaminants present in the environment, were deployed at three sites in the Great Barrier Reef (GBR). Extracts from these samplers were analysed for herbicides and applied to bioassays targeting integral life stages or functions of coral reef biota. Biota included scleractinian coral larvae, sea urchin larvae, a marine diatom and marine bacteria. Photosynthesis in the marine diatom Phaeodactylum tricornutum was inhibited at the sampled environmental concentration while an environmental concentration factor of 15 times inhibited luminescence in the marine bacterium Vibrio fischeri. Concentrations of 50 times sampled environmental levels of organic pollutants inhibited >90% of Acropora millepora settlement and 100-fold environmental enrichment inhibited 100% Heliocidaris tuberculata larval development. These results demonstrate the utility of pairing passive sampling with bioassays and reveal that mixtures of organic pollutants in the GBR have the potential to cause detrimental effects to coral reef biota.

  13. Chronic bioassays of rainbow trout fry with compounds representative of contaminants in Great Lakes fish

    USGS Publications Warehouse

    Passino-Reader, Dora R.; Berlin, William H.; Hickey, James P.

    1995-01-01

    To evaluate the hazard of organic compounds detected in Great Lakes fish by gas chromatography/mass spectrometry, we tested compounds representative of heterocyclic nitrogen compounds, polycyclic aromatic hydrocarbons, and cyclic alkanes and alkenes. Sixty-day bioassays on the effects of nicotine, phenanthrene, pinane, and pinene on the behavior, growth, and survival of rainbow trout fry, Oncorhynchus mykiss, were conducted in a large, constant-flow, temperature-controlled water system. The following 60-day LCSO's were determined (mg/L): nicotine 5.0, phenanthrene 0.2, pinane 0.8, and pinene 1.2. Values of lowest observed effects level (LOEL) and no observed effects level (NOEL) showed that growth was generally as sensitive an endpoint as behavior and was more sensitive than time of swim-up. The 60-day LC50 values for rainbow trout were compared with earlier acute bioassays with Daphnia pulexand rainbow trout and chronic bioassays with D.pulex conducted at the Great Lakes Science Center. Rainbow trout fry were less sensitive than daphnids in all tests, indicating that toxicity tests with daphnids should be protective of salmonid fry for these types of compounds. The results for representative compounds indicate that these classes of compounds should be included in aquatic risk assessments at sites in the Great Lakes.

  14. An evaluation of the effectiveness of utilizing bioassays in the assessment of contaminated sites

    SciTech Connect

    Mroz, R.; Carter, J.; Tay, K.L.; Doe, K.

    1995-12-31

    The purpose of this study was to evaluate the battery of biological tests recommended by Environment Canada in the document ``A Review of Whole Organism Bioassays for Assessing the Quality of Soil, Freshwater Sediment and Freshwater in Canada`` for the assessment of contaminated sites. Soil and sediment samples were collected from three contaminated sites in the Atlantic Region and subjected to biological and chemical tests. Four bioassays were conducted on the soil samples: lettuce (Lactuca sativa) seedling emergence, algal (Selenastrum capricornutum) population growth inhibition, earthworm (Eisenia andrel) survival and inhibition of light output in Microtox (Vibrio fischeri). Soil samples collected from Makinsons, Newfoundland had elevated levels of PCBs, total petroleum hydrocarbons (TPH) and heavy metals and showed some toxicity in the algal population growth inhibition test. Samples from the Weldon, New Brunswick site were high in TPH and were marginally toxic to Microtox and lettuce seedlings. The earthworm survival test did not appear sensitive to any of the contaminated soil samples. Freshwater sediment samples, collected from Five Island Lake, Nova Scotia had elevated PCB and heavy metal concentrations. These samples underwent four biological tests: midge (Chironomus tentans) survival, amphipod (Hyalella azteca) survival, algal population growth inhibition and Microtox. At 100% concentration, the sediment was toxic to the first three species, with toxicities ranging from marginal to high. For all samples, the bioassay results were compared to chemical analyses and, in most cases, there was a positive correlation between contaminant concentrations and toxicity.

  15. The interpretation of disease phenotypes to identify TSE strains following murine bioassay: characterisation of classical scrapie.

    PubMed

    Beck, Katy E; Vickery, Christopher M; Lockey, Richard; Holder, Thomas; Thorne, Leigh; Terry, Linda A; Denyer, Margaret; Webb, Paul; Simmons, Marion M; Spiropoulos, John

    2012-11-01

    Mouse bioassay can be readily employed for strain typing of naturally occurring transmissible spongiform encephalopathy cases. Classical scrapie strains have been characterised historically based on the established methodology of assessing incubation period of disease and the distribution of disease-specific vacuolation across the brain following strain stabilisation in a given mouse line. More recent research has shown that additional methods could be used to characterise strains and thereby expand the definition of strain "phenotype". Here we present the phenotypic characteristics of classical scrapie strains isolated from 24 UK ovine field cases through the wild-type mouse bioassay. PrPSc immunohistochemistry (IHC), paraffin embedded tissue blots (PET-blot) and Western blotting approaches were used to determine the neuroanatomical distribution and molecular profile of PrPSc associated with each strain, in conjunction with traditional methodologies. Results revealed three strains isolated through each mouse line, including a previously unidentified strain. Moreover IHC and PET-blot methodologies were effective in characterising the strain-associated types and neuroanatomical locations of PrPSc. The use of Western blotting as a parameter to define classical scrapie strains was limited. These data provide a comprehensive description of classical scrapie strain phenotypes on isolation through the mouse bioassay that can provide a reference for further scrapie strain identification.

  16. Bioassays as one of the Green Chemistry tools for assessing environmental quality: A review.

    PubMed

    Wieczerzak, M; Namieśnik, J; Kudłak, B

    2016-09-01

    For centuries, mankind has contributed to irreversible environmental changes, but due to the modern science of recent decades, scientists are able to assess the scale of this impact. The introduction of laws and standards to ensure environmental cleanliness requires comprehensive environmental monitoring, which should also meet the requirements of Green Chemistry. The broad spectrum of Green Chemistry principle applications should also include all of the techniques and methods of pollutant analysis and environmental monitoring. The classical methods of chemical analyses do not always match the twelve principles of Green Chemistry, and they are often expensive and employ toxic and environmentally unfriendly solvents in large quantities. These solvents can generate hazardous and toxic waste while consuming large volumes of resources. Therefore, there is a need to develop reliable techniques that would not only meet the requirements of Green Analytical Chemistry, but they could also complement and sometimes provide an alternative to conventional classical analytical methods. These alternatives may be found in bioassays. Commercially available certified bioassays often come in the form of ready-to-use toxkits, and they are easy to use and relatively inexpensive in comparison with certain conventional analytical methods. The aim of this study is to provide evidence that bioassays can be a complementary alternative to classical methods of analysis and can fulfil Green Analytical Chemistry criteria. The test organisms discussed in this work include single-celled organisms, such as cell lines, fungi (yeast), and bacteria, and multicellular organisms, such as invertebrate and vertebrate animals and plants.

  17. An assessment of the checkpoint bioassay concept for full scale wastewater UV reactor validation.

    PubMed

    Maka, P P; Lawryshyn, Y A

    2011-01-01

    In an effort to help policy makers and manufacturers understand the impact of parameter uncertainties on UV reactor performance, a numerical bioassay model was developed by integrating a UV reactor model based on computational fluid dynamics with a Monte Carlo model developed to account for parameter uncertainty. For the model implemented, it was determined that reactor performance uncertainty was less than 6%. The integrated model was used to evaluate several checkpoint bioassay criteria including one currently used by the California Department of Public Health. The model showed that these criteria failed to take into account the fact that in an ideal case, a full scale reactor will pass a single checkpoint test 50% of the time. In reality, differences in equipment measurement errors between the system validation and checkpoint bioassay, and limitations of the power law form of the dose monitoring equation in accurately representing system validation data will result in poorer than expected performance. It was suggested that such checkpoint criteria be modified by crediting the inherent over-sizing of full scale reactors.

  18. Fluorescence-based bioassays for the detection and evaluation of food materials.

    PubMed

    Nishi, Kentaro; Isobe, Shin-Ichiro; Zhu, Yun; Kiyama, Ryoiti

    2015-10-13

    We summarize here the recent progress in fluorescence-based bioassays for the detection and evaluation of food materials by focusing on fluorescent dyes used in bioassays and applications of these assays for food safety, quality and efficacy. Fluorescent dyes have been used in various bioassays, such as biosensing, cell assay, energy transfer-based assay, probing, protein/immunological assay and microarray/biochip assay. Among the arrays used in microarray/biochip assay, fluorescence-based microarrays/biochips, such as antibody/protein microarrays, bead/suspension arrays, capillary/sensor arrays, DNA microarrays/polymerase chain reaction (PCR)-based arrays, glycan/lectin arrays, immunoassay/enzyme-linked immunosorbent assay (ELISA)-based arrays, microfluidic chips and tissue arrays, have been developed and used for the assessment of allergy/poisoning/toxicity, contamination and efficacy/mechanism, and quality control/safety. DNA microarray assays have been used widely for food safety and quality as well as searches for active components. DNA microarray-based gene expression profiling may be useful for such purposes due to its advantages in the evaluation of pathway-based intracellular signaling in response to food materials.

  19. Fast and sensitive optical toxicity bioassay based on dual wavelength analysis of bacterial ferricyanide reduction kinetics.

    PubMed

    Pujol-Vila, F; Vigués, N; Díaz-González, M; Muñoz-Berbel, X; Mas, J

    2015-05-15

    Global urban and industrial growth, with the associated environmental contamination, is promoting the development of rapid and inexpensive general toxicity methods. Current microbial methodologies for general toxicity determination rely on either bioluminescent bacteria and specific medium solution (i.e. Microtox(®)) or low sensitivity and diffusion limited protocols (i.e. amperometric microbial respirometry). In this work, fast and sensitive optical toxicity bioassay based on dual wavelength analysis of bacterial ferricyanide reduction kinetics is presented, using Escherichia coli as a bacterial model. Ferricyanide reduction kinetic analysis (variation of ferricyanide absorption with time), much more sensitive than single absorbance measurements, allowed for direct and fast toxicity determination without pre-incubation steps (assay time=10 min) and minimizing biomass interference. Dual wavelength analysis at 405 (ferricyanide and biomass) and 550 nm (biomass), allowed for ferricyanide monitoring without interference of biomass scattering. On the other hand, refractive index (RI) matching with saccharose reduced bacterial light scattering around 50%, expanding the analytical linear range in the determination of absorbent molecules. With this method, different toxicants such as metals and organic compounds were analyzed with good sensitivities. Half maximal effective concentrations (EC50) obtained after 10 min bioassay, 2.9, 1.0, 0.7 and 18.3 mg L(-1) for copper, zinc, acetic acid and 2-phenylethanol respectively, were in agreement with previously reported values for longer bioassays (around 60 min). This method represents a promising alternative for fast and sensitive water toxicity monitoring, opening the possibility of quick in situ analysis.

  20. Comparison of the sensitivity of seven marine and freshwater bioassays as regards antidepressant toxicity assessment.

    PubMed

    Minguez, Laetitia; Di Poi, Carole; Farcy, Emilie; Ballandonne, Céline; Benchouala, Amira; Bojic, Clément; Cossu-Leguille, Carole; Costil, Katherine; Serpentini, Antoine; Lebel, Jean-Marc; Halm-Lemeille, Marie-Pierre

    2014-11-01

    The hazards linked to pharmaceutical residues like antidepressants are currently a major concern of ecotoxicology because they may have adverse effects on non-target aquatic organisms. Our study assesses the ecotoxicity of three antidepressants (fluoxetine, sertraline and clomipramine) using a battery of marine and freshwater species representing different trophic levels, and compares the bioassay sensitivity levels. We selected the following bioassays: the algal growth inhibition test (Skeletonema marinoi and Pseudokirchneriella subcapitata), the microcrustacean immobilization test (Artemia salina and Daphnia magna), development and adult survival tests on Hydra attenuata, embryotoxicity and metamorphosis tests on Crassostrea gigas, and in vitro assays on primary cultures of Haliotis tuberculata hemocytes. The results showed high inter-species variability in EC50-values ranging from 43 to 15,600 µg/L for fluoxetine, from 67 to 4,400 µg/L for sertraline, and from 4.70 µg/L to more than 100,000 µg/L for clomipramine. Algae (S. marinoi and P. subcapitata) and the embryo-larval stages of the oyster C. gigas were the most sensitive taxa. This raises an issue due to their ecological and/or economic importance. The marine crustacean A. salina was the least sensitive species. This difference in sensitivity between bioassays highlights the importance of using a test battery.

  1. DSSTOX NATIONAL TOXICOLOGY PROGRAM BIOASSAY ON-LINE DATABASE STRUCTURE-INDEX LOCATOR FILE: SDF FILE AND DOCUMENTATION

    EPA Science Inventory

    NTPBSI: National Toxicology Program Bioassay On-line Database Structure-Index Locator File. Database contains the results collected on approxiately 300 toxicity studies from shorter duration test and from genetic toxicity studies, both in vitro and in vivo tests.

  2. Laboratory Bioassays with Three Different Substrates to Test the Efficacy of Insecticides against Various Stages of Drosophila suzukii (Diptera: Drosophilidae)

    PubMed Central

    Pavlova, Aneliya Koleva; Dahlmann, Melanie; Hauck, Mirjam

    2017-01-01

    Rapid worldwide spread and polyphagous nature of the spotted wing Drosophila Drosophila suzukii Matsumura (Diptera: Drosophilidae) calls for efficient and selective control strategies to prevent severe economic losses in various fruit crops. The use of insecticides is one option for management of this invasive pest insect. Efficacy of insecticides is usually assessed first in laboratory bioassays, which are compounded by the cryptic nature of D. suzukii larvae and the fact that fruits used in bioassays often start to rot and dissolve before larvae have reached the adult stage. Here, we report on laboratory bioassays using three different types of substrates allowing a thorough screening of insecticides for their potential effects against D. suzukii eggs, larvae and adults. Suitability of our bioassays was validated in an assessment of the efficacy of four bioinsecticides and one synthetic insecticide against various developmental stages of D. suzukii. Water-apple juice agar used as a bioassay substrate allowed egg counting and observation of larval development due to its transparency, while apple-nutrition medium allowed complete metamorphosis. Use of grape berries in bioassays made it possible to assess effects of an insecticide present on a fruit’s surface on oviposition and larval hatch from eggs. Insecticides tested in these three different bioassays with acetamiprid, spinosad or natural pyrethrins as active ingredients achieved a significant D. suzukii control if they were applied before egg deposition. Number of adult flies was significantly reduced if the bioassay medium was treated with an azadirachtin A containing insecticide both before or after egg deposition. PMID:28042104

  3. The H4IIE cell bioassay as an indicator of dioxin-like chemicals in wildlife and the environment.

    PubMed

    Whyte, J J; Schmitt, C J; Tillitt, D E

    2004-01-01

    The H4IIE cell bioassay has proven utility as a screening tool for planar halogenated hydrocarbons (PHHs) and structurally similar chemicals accumulated in organisms from the wild. This bioassay has additional applications in hazard assessment of PHH exposed populations. In this review, the toxicological principles, current protocols, performance criteria, and field applications for the assay are described. The H4IIE cell bioassay has several advantages over the analytical measurement of PHHs in environmental samples, but conclusions from studies can be strengthened when both bioassay and analytical chemistry data are presented together. Often, the bioassay results concur with biological effects in organisms and support direct measures of PHHs. For biomonitoring purposes and prioritization of PHH-contaminated environments, the H4IIE bioassay may be faster and less expensive than analytical measurements. The H4IIE cell bioassay can be used in combination with other biomarkers such as in vivo measurements of CYP1A1 induction to help pinpoint the sources and identities of dioxin-like chemicals. The number of studies that measure H4IIE-derived TCDD-EQs continues to increase, resulting in subtle improvements over time. Further experiments are required to determine if TCDD-EQs derived from mammalian cells are adequate predictors of toxicity to non-mammalian species. The H4IIE cell bioassay has been used in over 300 published studies, and its combination of speed, simplicity, and ability to integrate the effects of complex contaminant mixtures makes it a valuable addition to hazard assessment and biomonitoring studies.

  4. Biomarkers and bioassays for detecting dioxin-like compounds in the marine environment.

    PubMed

    Hahn, Mark E

    2002-04-22

    The presence of toxic chemical contaminants in some marine organisms, including those consumed by humans, is well known. Monitoring the levels of such contaminants and their geographic and temporal variability is important for assessing and maintaining the safety of seafood and the health of the marine environment. Chemical analyses are sensitive and specific, but can be expensive and provide little information on the actual or potential biological activity of the contaminants. Biologically-based assays can be used to indicate the presence and potential effects of contaminants in marine animals, and therefore, have potential for routine monitoring of the marine environment. Halogenated aromatic hydrocarbons (HAHs) such as chlorinated dioxins, dibenzofurans, and biphenyls comprise a major group of marine contaminants. The most toxic HAHs (dioxin-like compounds) act through an intracellular receptor protein, the aryl hydrocarbon receptor, which is present in humans and many, but not all, marine animals. A toxic equivalency approach based on an understanding of this mechanism provides an integrated measure of the biological potency or activity of HAH mixtures. Biomarkers measured in marine animals indicate their exposure to these chemicals in vivo. Similarly, in vitro biomarker responses measured in cell culture bioassays can be used to assess the concentration of 'dioxin equivalents' in extracts of environmental matrices. Here, I have reviewed the types and relative sensitivities of mechanistically-based, in vitro bioassays for dioxin-like compounds, including assays of receptor-binding, DNA-binding and transcriptional activation of native (CYP1A) or reporter (luciferase) genes. Examples of their use in environmental monitoring are provided. Cell culture bioassays are rapid and inexpensive, and thus have great potential for routine monitoring of marine resources, including seafood. Several such assays exist, or are being developed, for a variety of marine

  5. Flow-through bioassay for measuring bioaccumulation of toxic substances from sediment

    USGS Publications Warehouse

    Mac, Michael J.; Edsall, Carol C.; Hesselberg, Robert J.; Sayers, Richard E.

    1984-01-01

    Over 10 million cubic meters of sediment are dredged annually from Great Lakes waterways. Because much of this material is taken from harbors, connecting channels, and other nearshore areas that often are contaminated with toxic substances, the sediments proposed for dredging need to be evaluated for the presence of bioavailable contaminants and the potential for toxicity to the biota. Sound decisions on the appropriate disposal of the dredged material can be made only after such an evaluation. Presently, no standardized procedure exists for evaluating dredged material in freshwater systems although current criteria for discharge of dredged material into marine water have been developed (USEPA/CE 1977). In the ocean discharge guideline, it is recommended that bioassays be conducted on liquid, solid, and suspended particulate phases of dredged material. because it appears that the solid phase has the greatest potential for environmental damage and because measurement of bioaccumulation must be made to evaluate sediments for disposal (USEPA/CE 1977, Seeyle and Mac 1983), we developed a bioassay for testing the solid phase of dredged material that measures the survival of organisms and, perhaps more important, the bioaccumulation of toxic substances by aquatic organisms from naturally contaminated sediments (Peddicord et al. 1980; Rubinstein et al. 1980, 1983; Seeyle st al. 1982), several have used testing methods that result in unacceptable mortality to control organisms (Bahnick et al. 1981, Prater et al. 1983). Our bioassay is intended to estimate the potential for bioaccumlation of contaminants from sediments that are not acutely toxic to test organisms, but are suspected of containing persistent contaminants. By using test organisms that are not highly susceptible to toxic compounds, the bioaccumulation test allows estimation of the potential food-chain accumulation of contaminants that may occur in local biota from surficial sediments. In practice

  6. Enhancement of the Chemiluminescence Response of Enzymatic Reactions by Plasmonic Surfaces for Biosensing Applications.

    PubMed

    Abel, Biebele; Odukoya, Babatunde; Mohammed, Muzaffer; Aslan, Kadir

    We report the enhancement of chemiluminescence response of horseradish peroxidase (HRP) in bioassays by plasmonic surfaces, which are comprised of (i) silver island films (SIFs) and (ii) metal thin films (silver, gold, copper, and nickel, 1 nm thick) deposited onto glass slides. A model bioassay, based on the interactions of avidin-modified HRP with a monolayer of biotinylated poly(ethylene-glycol)-amine, was employed to evaluate the ability of plasmonic surfaces to enhance chemiluminescence response of HRP. Chemiluminescence response of HRP in model bioassays were increased up to ~3.7-fold as compared to the control samples (i.e. glass slides without plasmonic nanoparticles), where the largest enhancement of the chemiluminescence response was observed on SIFs with high loading. These findings allowed us to demonstrate the use of SIFs (high loading) for the detection of a biologically relevant target protein (glial fibrillary acidic protein or GFAP), where the chemiluminescence response of the standard bioassay for GFAP was enhanced up to ~50% as compared to bioassay on glass slides.

  7. DEVELOPMENT OF A RAPID PROCEDURE TO ANALYSE Pu, Am AND 90Sr IN EMERGENCY URINE BIOASSAY IN CIEMAT BIOELIMINATION LABORATORY: METHOD VALIDATION BY EMERGENCY BIOASSAY INTERCOMPARISON EXERCISES.

    PubMed

    Sierra, I; Hernández, C

    2016-09-01

    After a radiological or nuclear incident, it is necessary to give a prompt response and to know the number of persons exposed to internal contamination, to evaluate the contamination levels in each person and even and to identify the radionuclides involved. In vitro laboratories routine monitoring measurements employed to quantify (90)Sr and actinides in urine require radiochemical separation and long counting time, which implies a minimum of 1 or 2 weeks to obtain the results, respectively. In this work, rapid radiochemical separation method applied directly to urine samples is presented. It is based on minimal sample preparation, without co-precipitation phase, using extraction resin columns and vacuum box technology. Pu isotopes and (241)Am are isolated, electrodeposited and measured by alpha spectrometry, whereas (90)Sr is measured by liquid scintillation counting. Finally, results of the participation in European Radiation Dosimetry Group intercomparison on Emergency Bioassay exercise and Bundesamt für Strahlenschutz exercise validate the accuracy of this procedure.

  8. An in vitro bioassay for xenobiotics using the SXR-driven human CYP3A4/lacZ reporter gene.

    PubMed

    Lee, Mi R; Kim, Yeon J; Hwang, Dae Y; Kang, Tae S; Hwang, Jin H; Lim, Chae H; Kang, Hyung K; Goo, Jun S; Lim, Hwa J; Ahn, Kwang S; Cho, Jung S; Chae, Kap R; Kim, Yong K

    2003-01-01

    The dose and time effect of nine xenobiotics, including 17beta-estradiol, corticosterone, dexamethasone, progesterone, nifedipine, bisphenol A, rifampicin, methamphetamine, and nicotine were investigated, in vitro, using human steroid and xenobiotics receptor (SXR)-binding sites on the human CYP3A4 promoter, which can enhance the linked lacZ reporter gene transcription. To test this, liver-specific SAP (human serum amyloid P component)-SXR (SAP/SXR) and human CYP3A4 promoter-regulated lacZ (hCYP3A4/lacZ) constructs were transiently transfected into HepG2 and NIH3T3 cells to compare the xenobiotic responsiveness between human and nonhuman cell lines. In the HepG2 cells, rifampicin, followed by corticosterone, nicotine, methamphetamine, and dexamethasone, exhibited enhanced levels of the lacZ transcript, whereas those of bisphenol A and nifedipine were found to be reduced. No significant responses were observed with 17beta-estradiol or progesterone. In addition, 17beta-estradiol and progesterone did not change the levels of the lacZ transcripts in the HepG2 cells, but did induce significant increases in the transcripts of the NIH3T3 cells. Treatment with corticosterone and dexamethasone, which were highly expressed in the HepG2 cells, did not affect the levels of the lacZ transcript in NIH3T3 cells. These results show that lacZ transcripts can be measured, rapidly and reproducibly, using reverse transcriptase-polymerase chain reaction (RT-PCR) based on the expression of the hCYP3A4/lacZ reporter gene, and was mediated by the SXR. Thus, this in vitro reporter gene bioassay is useful for measuring xenobiotic activities, and is a means to a better relevant bioassay, using human cells, human genes and human promoters, in order to get a closer look at actual human exposure.

  9. Importance of equilibration time in the partitioning and toxicity of zinc in spiked sediment bioassays

    USGS Publications Warehouse

    Lee, J.-S.; Lee, B.-G.; Luoma, S.N.; Yoo, H.

    2004-01-01

    The influences of spiked Zn concentrations (1-40 ??mol/g) and equilibration time (???95 d) on the partitioning of Zn between pore water (PW) and sediment were evaluated with estuarine sediments containing two levels (5 and 15 ??mol/g) of acid volatile sulfides (AVS). Their influence on Zn bioavailability was also evaluated by a parallel, 10-d amphipod (Leptocheirus plumulosus) mortality test at 5, 20, and 85 d of equilibration. During the equilibration, AVS increased (up to twofold) with spiked Zn concentration ([Zn]), whereas Zn-simultaneously extracted metals ([SEM]; Zn with AVS) remained relatively constant. Concentrations of Zn in PW decreased most rapidly during the initial 30 d and by 11- to 23-fold during the whole 95-d equilibration period. The apparent partitioning coefficient (Kpw, ratio of [Zn] in SEM to PW) increased by 10- to 20-fold with time and decreased with spiked [Zn] in sediments. The decrease of PW [Zn] could be explained by a combination of changes in AVS and redistribution of Zn into more insoluble phases as the sediment aged. Amphipod mortality decreased significantly with the equilibration time, consistent with decrease in dissolved [Zn]. The median lethal concentration (LC50) value (33 ??M) in the second bioassay, conducted after 20 d of equilibration, was twofold the LC50 in the initial bioassay at 5 d of equilibration, probably because of the change of dissolved Zn speciation. Sediment bioassay protocols employing a short equilibration time and high spiked metal concentrations could accentuate partitioning of metals to the dissolved phase and shift the pathway for metal exposure toward the dissolved phase.

  10. Guidance document for prepermit bioassay testing of low-level radioactive waste

    SciTech Connect

    Anderson, S.L.; Harrison, F.L.

    1990-11-01

    In response to the mandate of Public Law 92-532, the Marine Protection, Research, and Sanctuaries Act (MPRSA) of 1972, as amended, the Environmental Protection Agency (EPA) has developed a program to promulgate regulations and criteria to control the ocean disposal of radioactive wastes. The EPA seeks to understand the mechanisms for biological response of marine organisms to the low levels of radioactivity that may arise from the release of these wastes as a result of ocean-disposal practices. Such information will play an important role in determining the adequacy of environmental assessments provided to the EPA in support of any disposal permit application. Although the EPA requires packaging of low-level radioactive waste to prevent release during radiodecay of the materials, some release of radioactive material into the deep-sea environment may occur when a package deteriorates. Therefore, methods for evaluating the impact on biota are being evaluated. Mortality and phenotypic responses are not anticipated at the expected low environmental levels that might occur if radioactive materials were released from the low-level waste packages. Therefore, traditional bioassay systems are unsuitable for assessing sublethal effects on biota in the marine environment. The EPA Office of Radiation Programs (ORP) has had an ongoing program to examine sublethal responses to radiation at the cellular level, using cytogenetic end points. This technical guidance report represents prepermit bioassay procedures that potentially may be applicable to the assessment of effects from a mixture of radionuclides that could be released from a point source at the ocean bottom. Methodologies along with rationale and a discussion of uncertainty are presented for the sediment benthic bioassay protocols identified in this report.

  11. Bioassay of prion-infected blood plasma in PrP transgenic Drosophila.

    PubMed

    Thackray, Alana M; Andreoletti, Olivier; Bujdoso, Raymond

    2016-12-01

    In pursuit of a tractable bioassay to assess blood prion infectivity, we have generated prion protein (PrP) transgenic Drosophila, which show a neurotoxic phenotype in adulthood after exposure to exogenous prions at the larval stage. Here, we determined the sensitivity of ovine PrP transgenic Drosophila to ovine prion infectivity by exposure of these flies to a dilution series of scrapie-infected sheep brain homogenate. Ovine PrP transgenic Drosophila showed a significant neurotoxic response to dilutions of 10(-2) to 10(-10) of the original scrapie-infected sheep brain homogenate. Significantly, we determined that this prion-induced neurotoxic response in ovine PrP transgenic Drosophila was transmissible to ovine PrP transgenic mice, which is indicative of authentic mammalian prion detection by these flies. As a consequence, we considered that PrP transgenic Drosophila were sufficiently sensitive to exogenous mammalian prions to be capable of detecting prion infectivity in the blood of scrapie-infected sheep. To test this hypothesis, we exposed ovine PrP transgenic Drosophila to scrapie-infected plasma, a blood fraction notoriously difficult to assess by conventional prion bioassays. Notably, pre-clinical plasma from scrapie-infected sheep induced neurotoxicity in PrP transgenic Drosophila and this effect was more pronounced after exposure to samples collected at the clinical phase of disease. The neurotoxic phenotype in ovine PrP transgenic Drosophila induced by plasma from scrapie-infected sheep was transmissible since head homogenate from these flies caused neurotoxicity in recipient flies during fly-to-fly transmission. Our data show that PrP transgenic Drosophila can be used successfully to bioassay prion infectivity in blood from a prion-diseased mammalian host.

  12. Comparisons of laboratory bioassays and a whole-lake experiment: Rotifer responses to experimental acidification

    SciTech Connect

    Gonzalez, M.J.; Frost, T.M. )

    1994-02-01

    The authors test whether data from laboratory bioassays can be used to predict zooplankton responses during a whole-lake experiment using two rotifers, Keratella cochlearis and Keratella taurocephala. The acidification experiment was conducted in Little Rock Lake, Wisconsin, USA, which was divided into a reference basin maintained at a natural pH near 6.1 and a treatment basin which was acidified in 2-yr stages to pH values of 5.6, 5.2, and 4.7. Laboratory assays examined the effect of pH on reproduction under varied food conditions and survivorship without food. In the lake, the two rotifers showed strong and opposite responses to acidification: K. cochlearis decreased in abundance while K. taurocephala increased. In the laboratory bioassays, neither species was sensitive to pH when food conditions yielded high reproductive rates. When food was limited, K. cochlearis exhibited lower survivorship and a trend towards lower reproductive rates at lower pH. With limited food, K. taurocephala survivorship was either unaffected by pH or higher at high pH and its reproduction was slightly higher at intermediate pH. In situ experiments revealed that food conditions in the treatment basin lowered reproduction by K. cochlearis, indicating that a combined effect of food and pH caused its population decline. Neither food nor pH could explain the increase in K. taurocephala, which appeared to be linked to a reduction in its predators at lower pH. Overall, the analyses revealed substantial discrepancies between laboratory bioassays and in-lake responses. This was particularly the case for K. taurocephala, for which assays predicted no changes or a decline in abundance rather than the marked increase that actually occurred. The results suggest that caution should be used in extending results from laboratory assays to natural ecosystems.

  13. Development of marine sediment bioassays and toxicity tests for monitoring and regulation in Europe

    SciTech Connect

    Thain, J.; Matthiessen, P.

    1995-12-31

    There is a need in Europe and elsewhere for a broad suite of whole-sediment bioassays and toxicity tests which can be used for routine monitoring and assessment of the marine environment and for evaluating the toxic effects of chemicals which may find their way into sediments. Until recently, few European species had been incorporated into such tests but the availability of suitable methodologies is now increasing rapidly. Perhaps the most important recent activity in this area consisted of an international ring test of acute sediment toxicity test methods which was organized by the Oslo and Paris Commissions in 1993, using up to 4 offshore chemicals as test materials. It evaluated the performance of 4 acute (5--10 day) tests involving: the sea urchin Echinocardium cordatum, the bivalve mollusc Abra alba, the amphipod crustacean Corophium volutator, and the polychaete worm Arenicola marina. The ring test concluded that the C. volutator test was the most appropriate for evaluating offshore chemicals, but all these methods are now widely used in Europe, both as toxicity tests and as bioassays. For example, the A. marina procedure (which has both lethal and sublethal endpoints), in combination with the C. volutator method, is now routinely used in the UK for monitoring the toxicity of estuarine sediments. Further activities are in progress. Perhaps the most important is the development of chronic marine sediment tests and bioassays which can be used to assess the long-term effects of the many sedimentary contaminants which are able to persist in this type of habitat and possibly cause delayed effects on the growth and reproduction, etc. of benthic fauna.

  14. Application of a lux-based bioassay to assess soil toxicity

    SciTech Connect

    Paton, G.I. |; Campbell, C.D.; Rattray, E.A.S.; Glover, L.A.; Killham, K.

    1995-12-31

    The expression of prokaryotic bioluminescence is linked with cell metabolism and accordingly bioassays have been developed using naturally bioluminescent bacteria to assess ecotoxicity. Advances in biotechnology have allowed the isolation of the lux genes (responsible for bioluminescence) from marine organisms and their insertion into terrestrial bacteria. This has enabled the use of ecologically relevant bacteria to assess toxicity by measuring bioluminescence response in the presence of toxins. The lux genes were inserted into Pseudomonas fluorescens and Rhizobium leguminosarum biovar trifolii as a multi-copy plasmid and also integrated into the chromosome. It was found that in aqueous solutions the plasmid constructs were more sensitive than the chromosomal constructs to a range of toxins. The order of toxicity for Ps. fluorescens was Zn = Cu > Cd > Ni > Cr > DCP and for R. trifolii Zn > Cu > Cd > DCP > Cr. The lux based bioassays were more reproducible and sensitive than ATP and dehydrogenase assays and offered greater sensitivity than Photobacterium phosphoreum assays to assess toxicity of inorganic pollutants. Extracts from 4 soil types were spiked with a range of toxins and when EC{sub 50} values were determined it was shown that toxicity was related to soil characteristics. This enabled the assay to be used to assess the Lee Valley soil experiment which represents an important international study of the effect of the application of contaminated sewage to land. High metal application rates had been shown to have serious implications for soil ecology. Chemical analysis, carried out 26 years after sewage addition confirmed that soil extracts still had increased metal concentrations. The lux-based bioassays, which proved to be rapid, reproducible and sensitive confirmed that the metals were still biologically available and hence toxic.

  15. Neonatal mouse assay for tumorigenicity: alternative to the chronic rodent bioassay.

    PubMed

    Flammang, T J; Tungeln, L S; Kadlubar, F F; Fu, P P

    1997-10-01

    The chronic rodent bioassay for tumors has been utilized systematically for 25 years to identify chemicals with carcinogenic potential in man. In general, those chemicals exhibiting tumorigenicity at multiple sites in both mice and rats have been regarded as possessing strong carcinogenic potential in humans. In comparison, the value of data collected for those test chemicals exhibiting more sporadic tumorigenicity results (e.g., single species/single sex or dose-independent) has been questioned. As knowledge of the carcinogenic process has increased, several alternative test systems, usually faster and less expensive than the 2-year bioassay, have been suggested for identification of the strongly acting, transspecies carcinogens. The International Conference on Harmonization for Technical Requirements for the Registration of Pharmaceuticals for Human Use has proposed an international standard that allows for the use of one long-term rodent carcinogenicity study, plus one supplementary study to identify potential human pharmaceutical carcinogens. The neonatal mouse assay for tumorigenicity has been used since 1959; however, relative to other alternate tests, little has been written about this system. It is clear that this assay system successfully identifies transspecies carcinogens from numerous chemical classes, thus recommending itself as a strong candidate for a supplementary study to identify potential human carcinogens. In contrast, there are decidedly less data available from this assay in response to pharmaceuticals shown to exhibit weak and/or conflicting results in the 2-year bioassay, knowledge invaluable to the regulatory process. This paper reviews the historical development and our experience with the neonatal mouse assay and includes suggestions for a standardized protocol and strategies to document its response to "weak" and/or "nongenotoxic" carcinogens.

  16. Fast and accurate semantic annotation of bioassays exploiting a hybrid of machine learning and user confirmation.

    PubMed

    Clark, Alex M; Bunin, Barry A; Litterman, Nadia K; Schürer, Stephan C; Visser, Ubbo

    2014-01-01

    Bioinformatics and computer aided drug design rely on the curation of a large number of protocols for biological assays that measure the ability of potential drugs to achieve a therapeutic effect. These assay protocols are generally published by scientists in the form of plain text, which needs to be more precisely annotated in order to be useful to software methods. We have developed a pragmatic approach to describing assays according to the semantic definitions of the BioAssay Ontology (BAO) project, using a hybrid of machine learning based on natural language processing, and a simplified user interface designed to help scientists curate their data with minimum effort. We have carried out this work based on the premise that pure machine learning is insufficiently accurate, and that expecting scientists to find the time to annotate their protocols manually is unrealistic. By combining these approaches, we have created an effective prototype for which annotation of bioassay text within the domain of the training set can be accomplished very quickly. Well-trained annotations require single-click user approval, while annotations from outside the training set domain can be identified using the search feature of a well-designed user interface, and subsequently used to improve the underlying models. By drastically reducing the time required for scientists to annotate their assays, we can realistically advocate for semantic annotation to become a standard part of the publication process. Once even a small proportion of the public body of bioassay data is marked up, bioinformatics researchers can begin to construct sophisticated and useful searching and analysis algorithms that will provide a diverse and powerful set of tools for drug discovery researchers.

  17. Bioassay methods for detection of N-palmitoylbrevetoxin-B2 (BTX-B4).

    PubMed

    Bottein, Marie-Yasmine Dechraoui; Fuquay, Jennifer Maucher; Munday, Rex; Selwood, Andrew I; van Ginkel, Roel; Miles, Christopher O; Loader, Jared I; Wilkins, Alistair L; Ramsdell, John S

    2010-01-01

    Brevetoxins (BTXs) are a class of cyclic polyether toxins produced by the dinoflagellate Karenia brevis. These substances are subject to extensive conjugative metabolism in shellfish. BTX-B forms a conjugate with cysteine and is oxidized and reduced to yield BTX-B2, which is further modified by fatty acid addition via cysteine amide linkage to give biologically active brevetoxin metabolites. In this study, we evaluated the commonly used in vitro (ELISA, radioimmunoassay, receptor binding assay and N2A cytotoxicity assay) and in vivo mouse brevetoxin bioassays for the detection of the brevetoxin fatty acid conjugate N-palmitoylBTX-B2, and compared the results to those for dihydroBTX-B and BTX-B2. The receptor binding assay for N-palmitoylBTX-B2 showed comparable sensitivity to that for dihydroBTX-B, and an 11-fold higher sensitivity than for BTX-B2. Although the ELISA showed similarly high sensitivity to dihydroBTX-B and BTX-B2, with EC(50) values of ca. 0.26 ng/ml, it was 23 times less sensitive to N-palmitoylBTX-B2. On the other hand, the N2A cytotoxicity assay was highly sensitive to N-palmitoylBTX-B2, with an EC(50) of 0.15 ng/ml, but was 12- and 40-fold less sensitive to dihydroBTX-B and BTX-B2, respectively. The relative sensitivity of the N2A cytotoxicity assay for each of these metabolites paralleled that of the mouse bioassay (relative LD(50) values 1:20:30 for N-palmitoylBTX-B2:dihydroBTX-B:BTX-B2). We conclude that the most sensitive bioassay for dihydroBTX-B and BTX-B2 is the ELISA, whereas the N2A cytotoxicity assay is most sensitive for N-palmitoylBTX-B2.

  18. Determination of the androgenic potency of whole effluents using mosquitofish and trout bioassays.

    PubMed

    Bandelj, E; van den Heuvel, M R; Leusch, F D L; Shannon, N; Taylor, S; McCarthy, L H

    2006-12-01

    This study combined bioassay-derived and direct chemical analysis of steroidal compounds in pulp and paper and municipal sewage effluent in order to determine the cause of masculinization of female mosquitofish. The bioassays used in this study consisted of androgen and estrogen receptor binding, and aromatase inhibition using tissues from rainbow trout. This study observed no masculinization of female mosquitofish from a pulp and paper mill effluent that was previously observed to cause this effect. Mosquitofish sampled from the receiving environment of the same mill verified that masculinization was not occurring in the wild. The municipal sewage effluent also had no masculinizing effect. In vitro bioassays indicated significant sources of both androgens and estrogens in the effluents tested with sewage effluent having both the highest estradiol (41 ng/L) and testosterone (182 ng/L) equivalent concentration. These results could not be attributed to any particular compounds measured in the effluents. Two compounds implicated in the masculinization of mosquitofish by pulp and paper effluent, androstenedione and androstadienedione required relatively large (10-100 microg/L) waterborne concentrations to elicit a masculinizing effect and neither of these compounds are likely to occur at levels this high in the natural environment. The potent aromatase inhibitor, 4-hydroxyandrostenedione also did not cause masculinization at 100 microg/L indicating that masculinization did not occur through this mechanism. The mammalian anti-androgen, cyproterone acetate was only partially effective in mosquitofish and reduced the severity of masculinization in the presence of methyl testosterone. While neither effluent masculinized mosquitofish, there was a significant reduction of in vitro ovarian steroid production with the most severe effects observed with the sewage effluent. Overall, this study found the disappearance of a masculinizing effect that had been previously observed

  19. Predicting the carcinogenicity of chemicals in humans from rodent bioassay data

    SciTech Connect

    Goodman, G. School of Public Health, Boston, MA ); Wilson, R. )

    1991-08-01

    Regulatory agencies currently rely on rodent carcinogenicity bioassay data to predict whether or not a given chemical poses a carcinogenic threat to humans. The authors argue that it is always more useful to know a chemical's carcinogenic potency (with confidence limits) than to be able to say only qualitatively that it has been found to be a carcinogen. In a typical bioassay, a chemical is administered to groups of 50 to 100 rodents at the highest feasible level (the maximum tolerated dose) and rarely at less than 1/10 this dose in order to maximize the statistical significance of any increase in tumors that might result. Recently, much experimental work has focused on the mechanisms by which site-specific toxicity arising from chronic administration at the maximum tolerated dose may lead to carcinogenicity. Extrapolation of high-dose results to low dose does not take into consideration the possibility of a threshold dose, below which the carcinogenic potency is much lower or even zero. Threshold dose-response phenomena may be much more relevant to the etiology of cancer in the rodent bioassays than was earlier realized; if so, there is an even greater need for establishing dose-dependent potency estimates. The emphasis of this review is in the interspecies comparison of high-dose potencies. The qualitative and quantitative comparison of carcinogenicities between mice and rats and between rodents and humans is reviewed and discussed. They conclude that there is a good qualitative (yes/no) correlation for both the rat/mouse and the rodent/human comparison.

  20. Quantitative bioassays for measuring biologically functional gonadotropins based on eel gonadotropic receptors.

    PubMed

    Minegishi, Y; Dirks, R P; de Wijze, D L; Brittijn, S A; Burgerhout, E; Spaink, H P; van den Thillart, G E E J M

    2012-08-01

    Significant declines in eel stocks have been noted in many parts of the world. Because eel aquaculture is dependent on wild-caught juveniles, there is a need to achieve artificial reproduction. Adult eel maturation is currently induced by repeated injections of purified gonadotropin (human chorionic gonadotropin [hCG]) or pituitary extract. Thus the determination of the biological efficacy and quantification of internal levels of gonadotropic hormones is important for optimizing artificial reproduction protocols. To quantify the plasma levels of biologically functional gonadotropic hormones, we developed a bioassay for luteinizing hormone (LH) and follicle-stimulating hormone (FSH) based on the stable expression of receptors in HEK293 cells of the Japanese eel Anguilla japonica LH (ajLHR) and the European eel Anguilla anguilla FSH (aaFSHR), respectively. Such cells also contain a firefly luciferase reporter gene driven by a cAMP-responsive element (CRE-Luc). We found that the obtained stable cells, with ajLHR, responded linearly to a more than 100,000-fold concentration range of hCG diluted in saline. The cells with aaFSHR showed a linear response to a 1000-fold concentration range of salmon pituitary extract mixed with saline. The biological functionality of the LH and FSH bioassays was validated using hCG, human FSH, and pituitary extracts from salmon, carp and eel. Since the toxins in eel plasma damaged the HEK293 cells, the protocol was adapted to selectively inactivate the toxins by heating at 37°C for 24h. This process successfully enabled the monitoring of hormone levels in blood plasma sampled from hCG-injected eels. In this paper, we describe the development of gonadotropin bioassays that will be useful for improving reproduction protocols in eel aquaculture.

  1. Fast and accurate semantic annotation of bioassays exploiting a hybrid of machine learning and user confirmation

    PubMed Central

    Bunin, Barry A.; Litterman, Nadia K.; Schürer, Stephan C.; Visser, Ubbo

    2014-01-01

    Bioinformatics and computer aided drug design rely on the curation of a large number of protocols for biological assays that measure the ability of potential drugs to achieve a therapeutic effect. These assay protocols are generally published by scientists in the form of plain text, which needs to be more precisely annotated in order to be useful to software methods. We have developed a pragmatic approach to describing assays according to the semantic definitions of the BioAssay Ontology (BAO) project, using a hybrid of machine learning based on natural language processing, and a simplified user interface designed to help scientists curate their data with minimum effort. We have carried out this work based on the premise that pure machine learning is insufficiently accurate, and that expecting scientists to find the time to annotate their protocols manually is unrealistic. By combining these approaches, we have created an effective prototype for which annotation of bioassay text within the domain of the training set can be accomplished very quickly. Well-trained annotations require single-click user approval, while annotations from outside the training set domain can be identified using the search feature of a well-designed user interface, and subsequently used to improve the underlying models. By drastically reducing the time required for scientists to annotate their assays, we can realistically advocate for semantic annotation to become a standard part of the publication process. Once even a small proportion of the public body of bioassay data is marked up, bioinformatics researchers can begin to construct sophisticated and useful searching and analysis algorithms that will provide a diverse and powerful set of tools for drug discovery researchers. PMID:25165633

  2. Analysis of polonium-210 in food products and bioassay samples by isotope-dilution alpha spectrometry.

    PubMed

    Lin, Zhichao; Wu, Zhongyu

    2009-05-01

    A rapid and reliable radiochemical method coupled with a simple and compact plating apparatus was developed, validated, and applied for the analysis of (210)Po in variety of food products and bioassay samples. The method performance characteristics, including accuracy, precision, robustness, and specificity, were evaluated along with a detailed measurement uncertainty analysis. With high Po recovery, improved energy resolution, and effective removal of interfering elements by chromatographic extraction, the overall method accuracy was determined to be better than 5% with measurement precision of 10%, at 95% confidence level.

  3. Biotesting of radioactively contaminated forest soils using barley-based bioassay

    NASA Astrophysics Data System (ADS)

    Mel’nikova, T. V.; Polyakova, L. P.; Oudalova, A. A.

    2017-01-01

    Findings from radioactivity and phytotoxicity study are presented for soils from nine study-sites of the Klintsovsky Forestry located in the Bryansk region that were radioactively contaminated after the Chernobyl accident. According to the bioassay based on barley as test-species, stimulating effect of the soils analyzed is revealed for biological indexes of the length of barley roots and sprouts. From data on 137Cs specific activities in soils and plant biomass, the migration potential of radionuclide in the "soil-plant" system is assessed as a transfer factor. With correlation analysis, an impact of 137Cs in soil on the biological characteristics of barley is estimated.

  4. BIOASSAY OF POLLUTED SEDIMENTS AND REDUCTION OF TOXICITY BY AEROBIC TREATMENT

    NASA Astrophysics Data System (ADS)

    Sumikura, Mitsuhiro; Kojima, Toshikazu; Okamura, Kazuo; Horiuchi, Sumio

    Aerobic treatment is being studied as an efficient in-situ remediation method for polluted sediments. This treatment method is able to decompose organic substances that are otherwise difficult to degrade. Changes in toxicity during such treatment is the subject of this study. Bioassay utilizing Daphnia magna was conducted for toxicity assessment of sediment. Laboratory treatment experiment was conducted, and changes in toxicity and dissolved ion concentrations were measured.Conclusions from this test are, as follows; (1) toxicity of chloride, ammonia, and sulfide was found to be masked by the coexisting materials in the sample matrix, and (2) changes of toxicity was dependent on the forms of sulfur and nitrogen species.

  5. Promising Aedes aegypti Repellent Chemotypes Identified through Integrated QSAR, Virtual Screening, Synthesis, and Bioassay

    PubMed Central

    Oliferenko, Polina V.; Oliferenko, Alexander A.; Poda, Gennadiy I.; Osolodkin, Dmitry I.; Pillai, Girinath G.; Bernier, Ulrich R.; Tsikolia, Maia; Agramonte, Natasha M.; Clark, Gary G.; Linthicum, Kenneth J.; Katritzky, Alan R.

    2013-01-01

    Molecular field topology analysis, scaffold hopping, and molecular docking were used as complementary computational tools for the design of repellents for Aedes aegypti, the insect vector for yellow fever, chikungunya, and dengue fever. A large number of analogues were evaluated by virtual screening with Glide molecular docking software. This produced several dozen hits that were either synthesized or procured from commercial sources. Analysis of these compounds by a repellent bioassay resulted in a few highly active chemicals (in terms of minimum effective dosage) as viable candidates for further hit-to-lead and lead optimization effort. PMID:24039693

  6. Discovery of active components in herbs using chromatographic separation coupled with online bioassay.

    PubMed

    De-Qiang, Li; Zhao, Jing; Wu, Dong; Shao-Ping, Li

    2016-05-15

    Discovery of bioactive compounds from complex mixtures is a challenge. In past decades, several strategies were developed and implemented for rapid and effective screening and characterization of bioactive components in complex matrices. This review mainly focused on the online strategies, which integrated the separation science, mass spectrometry, and bioactivity screening in a single platform, allowing simultaneous screening and characterization of active compounds from complex matrices, especially from the herbs. The online screening methodologies, including pre-column affinity-based screening and post-column bioassay, were discussed and their applied examples were also presented to illustrate the strengths and limitations of these approaches.

  7. Principles for the selection of doses in chronic rodent bioassays. ILSI Risk Science Working Group on Dose Selection.

    PubMed

    Foran, J A

    1997-01-01

    Dose selection in chronic rodent bioassays has been one of the most debated issues in risk assessment. The Committee on Risk Assessment Methods of the National Research Council attempted, but failed, in 1993 to reach consensus on how to select doses for chronic rodent bioassays. However, a more recent effort conducted by the ILSI Risk Science Institute has resulted in a consensus set of principles for dose selection, including selection of the highest dose for chronic rodent bioassays. The principles encourage a move away from sole reliance on a maximum tolerated dose (MTD), as it has been traditionally defined (primarily by body weight and histopathology), and toward the use of sound scientific and toxicologic principles for the selection of all doses in the chronic bioassay. Specifically, the principles recommend that dose selection for chronic studies must be based on sound toxicologic principles; dose selection should consider human exposure; dose selection should be based on a variety of endpoints and effects derived from prechronic studies; and dose selection should consider physicochemical and other factors. Implementation of the principles internationally will have two important benefits; improvement in the quality and consistency of the rodent bioassay and international harmonization of dose selection procedures.

  8. Bioassay-derived dioxin equivalent concentrations in gonads and livers of the Atlantic cod females from the Baltic Sea.

    PubMed

    Dabrowska, Henryka; Murk, Albertinka J; van den Berg, Hans J

    2010-11-01

    The DR-H4IIE.Luc bioassay is based on the ability of dioxin and dioxin-like contaminants to activate the AhR and its signal transduction pathway, a mechanism through which these contaminants elicit their toxic effects. The bioassay was used to examine the total dioxin-equivalent (TEQ) toxicity in gonads and livers of cod females from the southern Baltic Sea. The bioassay-derived TEQ-luc was measured after 24-h and 48-h exposure periods. Mean concentrations in the 24-h bioassay were 95 and 35 pg TEQ-luc g(-1) lipid in gonads and livers, respectively, and 58 and 38 pg TEQ-luc g(-1) lipid in the 48-h bioassay, respectively. The 48-h TEQ-luc levels displayed significant relationships with ΣPCB(7) and selected PCB congeners but not with the TEQ(DLPCB-REP). Levels in gonads approached 10% of the LC50 for developing larvae of other marine fish, yet the impact on survival of the cod during its early life remains to be assessed in a future.

  9. De novo morphogenesis of testis tissue: an improved bioassay to investigate the role of VEGF165 during testis formation.

    PubMed

    Dores, Camila; Dobrinski, Ina

    2014-07-01

    De novo formation of testis tissue from single-cell suspensions allows manipulation of different testicular compartments before grafting to study testicular development and the spermatogonial stem cell niche. However, the low percentages of newly formed seminiferous tubules supporting complete spermatogenesis and lack of a defined protocol have limited the use of this bioassay. Low spermatogenic efficiency in de novo formed tissue could result from the scarcity of germ cells in the donor cell suspension, cell damage caused by handling or from hypoxia during tissue formation in the host environment. In this study, we compared different proportions of spermatogonia in the donor cell suspension and the use of Matrigel as a scaffold to support de novo tissue formation and spermatogenesis. Then, we used the system to investigate the role of vascular endothelial growth factor 165 (VEGF165) during testicular morphogenesis on blood vessel and seminiferous tubule formation, and on presence of germ cells in the de novo developed tubules. Our results show that donor cell pellets with 10×10(6) porcine neonatal testicular cells in Matrigel efficiently formed testis tissue de novo. Contrary to what was expected, the enrichment of the cell suspension with germ cells did not result in higher numbers of tubules supporting spermatogenesis. The addition of VEGF165 did not improve blood vessel or tubule formation, but it enhanced the number of tubules containing spermatogonia. These results indicate that spermatogenic efficiency was improved by the addition of Matrigel, and that VEGF165 may have a protective role supporting germ cell establishment in their niche.

  10. Rapid yeast estrogen bioassays stably expressing human estrogen receptors alpha and beta, and green fluorescent protein: a comparison of different compounds with both receptor types.

    PubMed

    Bovee, Toine F H; Helsdingen, Richard J R; Rietjens, Ivonne M C M; Keijer, Jaap; Hoogenboom, Ron L A P

    2004-07-01

    Previously, we described the construction of a rapid yeast bioassay stably expressing human estrogen receptor (hERalpha) and yeast enhanced green fluorescent protein (yEGFP) in response to estrogens. In the present study, the properties of this assay were further studied by testing a series of estrogenic compounds. Furthermore, a similar assay was developed based on the stable expression of human estrogen receptor beta (hERbeta). When exposed to 17beta-estradiol, the maximum transcriptional activity of the ERbeta cytosensor was only about 40% of the activity observed with ERalpha, but the concentration where half-maximal activation is reached (EC50), was about five times lower. The relative estrogenic potencies (REP), defined as the ratio between the EC50 of 17beta-estradiol and the EC50 of the compound, of the synthetic hormones dienestrol, hexestrol and especially mestranol were higher with ER, while DES was slightly more potent with ERbeta. The gestagens progesterone and medroxyprogesterone-acetate showed no response, whereas the androgen testosterone showed a very weak response. The anabolic agent, 19-nortestosterone showed a clear dose-related response with estrogen receptor but not beta. The phytoestrogens coumestrol, genistein, genistin, daidzein, daidzin and naringenin were relatively more potent with ERbeta. Ranking of the estrogenic potency with ER was: 17beta-estradiol > 8-prenylnaringenin > coumestrol > zearalenone > genistein > genistin > naringenin. The ranking with the ERbeta was: 17beta-estradiol > coumestrol > genistein > zearalenone > 8-prenylnaringen > daidzein > naringenin > genistin > daidzin. The hop estrogen 8-prenylnaringenin is relatively more potent with ERalpha. These data show that the newly developed bioassays are valuable tools for the rapid and high-throughput screening for estrogenic activity.

  11. Evaluation of bioassays to monitor surface microlayer toxicity in tropical marine waters.

    PubMed

    Rumbold, D G; Snedaker, S C

    1997-02-01

    Bioassays were developed, using embryos of: coral,Montastraea faveolata; graysby, Epinephelus cruentatus;grouper, Epinephelus adscensionis x gruttatus (hybrid); queenconch, Strombus gigas; rock-boring urchin, Echinodermatalucunter; spotted seatrout, Cynoscion nebulosus; variegatedurchin, Lytechinus variegatus; winged pearl oyster, Pteriacolymbus; and yellowtail snapper, Ocyurus chrysurus. Relativesensitivities and precison of various species-endpoint combinations wereevaluated using three reference toxicants: copper, sodium dodecyl sulfate,and Dibrom(R). The 24-h P. colymbus embryo test had the best overallsensitivity and exhibited a high degree of precision. However, oyster embryoswere difficult to obtain and did not aggregate at the air-water interface.Therefore, the P. colymbus embryo test was deemed unsuitable for useas a bioassay for monitoring sea-surface microlayer (SSML) toxicity. Testsbased on normal development of L. variegatus to the early pluteus 3stage and percent normal-live C. nebulosus larvae at 48 h wererelatively sensitive and exhibited good replicability and repeatability. TheL. variegatus urchin embryo test was also found to be highlyreproducible. The results of this comparative study indicated that L.variegatus and C. nebulosus were suitable surrogates forcoral-reef species in toxicity assessments of the SSML.

  12. Antiplasmodial Properties and Bioassay-Guided Fractionation of Ethyl Acetate Extracts from Carica papaya Leaves.

    PubMed

    Melariri, Paula; Campbell, William; Etusim, Paschal; Smith, Peter

    2011-01-01

    We investigated the antiplasmodial properties of crude extracts from Carica papaya leaves to trace the activity through bioassay-guided fractionation. The greatest antiplasmodial activity was observed in the ethyl acetate crude extract. C. papaya showed a high selectivity for P. falciparum against CHO cells with a selectivity index of 249.25 and 185.37 in the chloroquine-sensitive D10 and chloroquine-resistant DD2 strains, respectively. Carica papaya ethyl acetate extract was subjected to bioassay-guided fractionation to ascertain the most active fraction, which was purified and identified using high-pressure liquid chromatography (HPLC) and GC-MS (Gas chromatography-Mass spectrometry) methods. Linoleic and linolenic acids identified from the ethyl acetate fraction showed IC(50) of 6.88 μg/ml and 3.58 μg/ml, respectively. The study demonstrated greater antiplasmodial activity of the crude ethyl acetate extract of Carica papaya leaves with an IC(50) of 2.96 ± 0.14 μg/ml when compared to the activity of the fractions and isolated compounds.

  13. Tradescantia-micronucleus (Trad-MCN) bioassay on clastogenicity of wastewater and in situ monitoring.

    PubMed

    Ruiz, E F; Rabago, V M; Lecona, S U; Perez, A B; Ma, T H

    1992-11-01

    The Tradescantia-micronucleus (Trad-MCN) bioassay was used to determine the clastogenicity of wastewater samples collected from the Arena canal which contains effluent from the industrial district Benito Juarez of the city of Queretaro, Mexico. Fifteen wastewater samples which were collected, in most cases, at bi-weekly intervals beginning in September 1986 through February 1988, after a 3-fold dilution were used to treat Tradescantia plant cuttings. The clastogenicity expressed in terms of micronucleus frequencies of treated groups (30 h of treatment without recovery time) was significantly (0.01) higher than that of the tapwater control groups. The Trad-MCN bioassay was also used for in situ monitoring of air pollutants for the clastogenicity at 3 sites near the industrial and residential areas (Flores Magon, Conalep and Bellas Artes) of the city of Queretaro. Fourteen monitoring trips were made to each of the 3 sites at monthly intervals beginning in May 1988 through June 1990. Seasonal variation of micronucleus frequencies was exhibited with the peak clastogenicities shown in May and June 1988, June 1989 and April 1990 at the three sites. Micronucleus frequencies of all the exposed groups at the Conalep site, a predominantly industrial area, were markedly higher than that of the laboratory control groups throughout the 2-year period.

  14. Screening the Toxicity of Selected Personal Care Products Using Embryo Bioassays: 4-MBC, Propylparaben and Triclocarban.

    PubMed

    Torres, Tiago; Cunha, Isabel; Martins, Rosário; Santos, Miguel M

    2016-10-21

    Recently, several emerging pollutants, including Personal Care Products (PCPs), have been detected in aquatic ecosystems, in the ng/L or µg/L range. Available toxicological data is limited, and, for certain PCPs, evidence indicates a potential risk for the environment. Hence, there is an urgent need to gather ecotoxicological data on PCPs as a proxy to improve risk assessment. Here, the toxicity of three different PCPs (4-Methylbenzylidene Camphor (4-MBC), propylparaben and triclocarban) was tested using embryo bioassays with Danio rerio (zebrafish) and Paracentrotus lividus (sea urchin). The No Observed Effect Concentration (NOEC) for triclocarban was 0.256 µg/L for sea urchin and 100 µg/L for zebrafish, whereas NOEC for 4-MBC was 0.32 µg/L for sea urchin and 50 µg/L for zebrafish. Both PCPs impacted embryo development at environmentally relevant concentrations. In comparison with triclocarban and 4-MBC, propylparaben was less toxic for both sea urchin (NOEC = 160 µg/L) and zebrafish (NOEC = 1000 µg/L). Overall, this study further demonstrates the sensitivity of embryo bioassays as a high-throughput approach for testing the toxicity of emerging pollutants.

  15. Ammonium toxicity at high pH in a marine bioassay using Corophium volutator.

    PubMed

    Kater, Belinda J; Dubbeldam, Marco; Postma, Jaap F

    2006-10-01

    Two forms of ammonium exist in water: un-ionized ammonia NH3 and ionized ammonium NH4+. The toxicity to many aquatic organisms is primarily attributed to the NH3 (un-ionized) species, with the NH4+ ion (ionized) species being relatively less toxic. The pH level influences the degree of ionization. It is therefore very important that quality criteria be derived for total ammonium levels at several pH values in order to allow correct interpretation of the sediment bioassay with Corophium volutator. The responses of Corophium to total ammonium were studied in a series of pH-controlled experiments. The LC50 of total ammonium showed a significant decrease with increasing pH, in both water-only and sediment experiments. The results indicated a combined NH4+ and NH3 toxicity at pH levels less than 8.3. The results can be used to set pH-dependent water quality criteria for total ammonium in overlying water in a 10-day sediment bioassay with Corophium volutator.

  16. Using marine bioassays to classify the toxicity of Dutch harbor sediments.

    PubMed

    Stronkhorst, Joost; Schipper, Cor; Brils, Jos; Dubbeldam, Marco; Postma, Jaap; van de Hoeven, Nelly

    2003-07-01

    A procedure was developed to assess contaminated marine sediments from Dutch harbors for possible adverse biological effects using three laboratory bioassays: A 10-d survival test with the amphipod Corophium volutator, a 14-d survival test with the heart urchin Echinocardium cordatum (adults), and the bioluminescence inhibition test with the bacterium Vibrio fischeri (Microtox solid phase test LSP]). Microtox results were mathematically corrected for the modifying influence of fine sediment particles. After a validation procedure on test performance and modifying factors, respectively, 81%, 99%, and 90% of the amphipod, heart urchin, and Microtox results were approved. Lower and upper threshold limits for biological effects were set at respectively 24 and 30% mortality for C. volutator, 27 and 35% mortality for E. cordatum, and 24 and 48 toxic units for the Microtox SP based on significant differences with control sediment and the performance of reference sediments. The bioassays clearly distinguished harbor sediments that give rise to acute effects and those that do not. Threshold limits for the amphipods, heart urchins, and bacteria were exceeded in, respectively, 9 to 17%, 33 to 40%, and 23 to 50% of the sediment samples. Highest effects were observed in sediments from the northerly harbors; there was significantly less response in sediments from the Delta Region and the port of Rotterdam (The Netherlands). The procedure outlined in this paper can be used for routine screening of contaminated dredged material that is proposed for open water disposal.

  17. Field test of a bioassay procedure for assessing habitat quality on fish spawning grounds

    USGS Publications Warehouse

    Manny, Bruce A.; Jude, David J.; Eshenroder, Randy L.

    1989-01-01

    A bioassay procedure to assess habitat quality was tested on Port Austin reef in southern Lake Huron, a spawning area of lake trout Salvelinus namaycush. In 1986, Plexiglas incubators filled with fertilized lake trout eggs were buried by scuba divers in rock rubble at two sites. The incubators then were attached to chains between large trap-net anchors on the bottom and left over winter. At one site, egg hatch rate was significantly higher in incubators that remained buried in substrate (24%) than in incubators that were dislodged out onto the substrate (13%). At the other, more exposed site, no significant difference was found in percent hatch between eggs that incubated in (10%) and on (8%) the substrate. Percent hatch at both sites was significantly lower than that (40%) of eggs from the same source that were incubated in controlled laboratory conditions. In autumn, concentrations of dissolved ammonia, hydrogen sulfide, and nitrate near bottom and in the substrate posed no threat to lake trout embryos and were not correlated with hatch rate; concentrations differed significantly between the two sites. During winter, 15 cm of sediment settled from the water onto the reef but did not accumulate or smother the eggs. The bioassay procedure is easy to implement, is recommended for use in the Great Lakes, and could be adapted easily for use elsewhere.

  18. A battery of bioassays for the evaluation of phenanthrene biotoxicity in soil.

    PubMed

    Khan, Muhammad Imran; Cheema, Sardar Alam; Tang, Xianjin; Hashmi, Muhammad Zaffar; Shen, Chaofeng; Park, Joonhong; Chen, Yingxu

    2013-07-01

    A battery of bioassays was used to assess the ecotoxicological risk of soil spiked with a range of phenanthrene levels (0.95, 6.29, 38.5, 58.7, 122, and 303 μg g(-1) dry soil) and aged for 69 days. Multiple species (viz. Brassica rapa, Eisenia feotida, Vibrio fischeri), representing different trophic levels, were used as bioindicator organisms. Among acute toxicity assays tested, the V. fischeri luminescence inhibition assay was the most sensitive indicator of phenanthrene biotoxicity. More than 15 % light inhibition was found at the lowest phenanthrene level (0.95 μg g(-1)). Furthermore, comet assay using E. fetida was applied to assess genotoxicity of phenanthrene. The strong correlation (r (2) ≥ 0.94) between phenanthrene concentration and DNA damage indicated that comet assay is appropriate for testing the genotoxic effects of phenanthrene-contaminated soil. In the light of these results, we conclude that the Microtox test and comet assay are robust and sensitive bioassays to be employed for the risk evaluation of polycyclic aromatic hydrocarbon-contaminated soil.

  19. Sea-urchin Embryo Bioassay for in situ Evaluation of the Biological Quality of Coastal Seawater

    NASA Astrophysics Data System (ADS)

    Beiras, R.; Vázquez, E.; Bellas, J.; Lorenzo, J. I.; Fernández, N.; Macho, G.; Mariño, J. C.; Casas, L.

    2001-01-01

    The Paracentrotus lividus sea-urchin embryo bioassay, consisting of incubation of fertilized eggs in test water and measurement of the percentage of four-armed plutei larvae developed after the incubation period (2-3 days), has been adapted for in situ evaluation of seawater quality in coastal areas. Mature sea-urchins are dissected in situ and fertilization is performed in the field; fertilized eggs are delivered into screw lid 50-ml cylinders with 20 μm nylon mesh in both ends filled with sieved local seawater. The cylinders, tied to 60-cm ropes with weights on one end and buoys in the other one, are placed by scuba divers in the test sites at subtidal level and recovered after the incubation period. The contents of each cylinder are then transferred into a vial, fixed with formalin and observed directly under an inverted microscope to record the percentage ( N=100) and size (length, N=25) of four-arm pluteus larvae. Our results show that the bioassay can discriminate between well known polluted and unpolluted sites, but further improvement is needed in order to: (1) take into account differences of temperature between sites; (2) minimize larval mortality due to reasons other than pollution.

  20. Screening the Toxicity of Selected Personal Care Products Using Embryo Bioassays: 4-MBC, Propylparaben and Triclocarban

    PubMed Central

    Torres, Tiago; Cunha, Isabel; Martins, Rosário; Santos, Miguel M.

    2016-01-01

    Recently, several emerging pollutants, including Personal Care Products (PCPs), have been detected in aquatic ecosystems, in the ng/L or µg/L range. Available toxicological data is limited, and, for certain PCPs, evidence indicates a potential risk for the environment. Hence, there is an urgent need to gather ecotoxicological data on PCPs as a proxy to improve risk assessment. Here, the toxicity of three different PCPs (4-Methylbenzylidene Camphor (4-MBC), propylparaben and triclocarban) was tested using embryo bioassays with Danio rerio (zebrafish) and Paracentrotus lividus (sea urchin). The No Observed Effect Concentration (NOEC) for triclocarban was 0.256 µg/L for sea urchin and 100 µg/L for zebrafish, whereas NOEC for 4-MBC was 0.32 µg/L for sea urchin and 50 µg/L for zebrafish. Both PCPs impacted embryo development at environmentally relevant concentrations. In comparison with triclocarban and 4-MBC, propylparaben was less toxic for both sea urchin (NOEC = 160 µg/L) and zebrafish (NOEC = 1000 µg/L). Overall, this study further demonstrates the sensitivity of embryo bioassays as a high-throughput approach for testing the toxicity of emerging pollutants. PMID:27775672

  1. Assessing the detoxication efficiencies of wastewater treatment processes using a battery of bioassays/biomarkers.

    PubMed

    Ma, Mei; Li, Jian; Wang, Zijian

    2005-11-01

    A battery of in vitro bioassays, including a Neutral Red (NR) assay using MCF-7 cells for predicting cytotoxic chemicals, an ethoxy resorufin-O-deethylase (EROD) activity assay using H4IIE cells to check for dioxin-like chemicals, and a recombinant gene yeast assay for screening estrogenic chemicals, was conducted to assess the removal efficiencies of trace toxic chemicals by different treatment processes in the waste water treatment plant (WWTP). The effluents were extracted by solid phase extraction (SPE) and were fractionated into three fractions based on polarities. The battery of bioassays was performed for each fraction. In the battery, the toxicities of the effluents were described according to their modes of actions (MOA) or biomarkers and the properties of the toxic chemicals were categorized by their polarities and MOAs. The proposed procedure could be used as a tool to diagnose the toxic characteristics of the complicate mixture. The results showed that cytotoxic, dioxin-like and estrogenic chemicals could be detected in all samples. In the influent, cytotoxic and dioxin-like chemicals were mainly in polar fraction and estrogenic chemicals were in non-polar and moderate-polar fractions. The secondary treatment (active sludge) could remove a small amount of these toxicants. Among different types of advanced treatments, flocculation was good enough to remove most of the cytotoxic chemicals and a combination of flocculation, ozone oxidation, and post-biological treatment could eliminate most of the dioxin-like and estrogenic chemicals.

  2. Automated cytochrome c oxidase bioassay developed for ionic liquids' toxicity assessment.

    PubMed

    Costa, Susana P F; Martins, Bárbara S F; Pinto, Paula C A G; Saraiva, M Lúcia M F S

    2016-05-15

    A fully automated cytochrome c oxidase assay resorting to sequential injection analysis (SIA) was developed for the first time and implemented to evaluate potential toxic compounds. The bioassay was validated by evaluation of 15 ionic liquids (ILs) with distinct cationic head groups, alkyl side chains and anions. The assay was based on cytochrome c oxidase activity reduction in presence of tested compounds and quantification of inhibitor concentration required to cause 50% of enzyme activity inhibition (EC50). The obtained results demonstrated that enzyme activity was considerably inhibited by BF4 anion and ILs incorporating non-aromatic pyrrolidinium and tetrabutylphosphonium cation cores. Emim [Ac] and chol [Ac], on contrary, presented the higher EC50 values among the ILs tested. The developed automated SIA methodology is a simple and robust high-throughput screening bioassay and exhibited good repeatability in all the tested conditions (rsd<3.7%, n=10). Therefore, it is expected that due to its simplicity and low cost, the developed approach can be used as alternative to traditional screening assays for evaluation of ILs toxicity and identification of possible toxicophore structures. Additionally, the results presented in this study provide further information about ILs toxicity.

  3. Application of genetically altered models as replacement for the lifetime mouse bioassay in pharmaceutical development.

    PubMed

    Alden, Carl; Smith, Peter; Morton, Dan

    2002-01-01

    The international pharmaceutical regulatory academic and industrial toxicology communities are collaborating to improve the efficiency and effectiveness of cancer hazard identification based on dramatic improvements in our understanding of the cancer process. Guidelines emanating from the International Conference on Harmonization provide for use of in vivo alternatives. Standard practices utilizing lifetime rat and mouse studies are recognized as seriously flawed with over 80% false positive rates. Furthermore, tobacco, the most important human carcinogen commercialized by industry, is negative in these traditional lifetime studies. The lifetime mouse bioassay is generally recognized in pharmaceutical development as not adding value in safety assessment. An international consortium under the aegis of ILSI has recently completed an evaluation of alternative mouse cancer models. Transgenic models are less expensive, use fewer animals and take less time than traditional lifetime bioassays. These alternative models have now been sufficiently evaluated to be considered useful in the safety assessment plan for pharmaceuticals in development. Specifically for example, the rasH2 appears useful in detecting nongenotoxic as well as genotoxic rodent tumorigens with improved concordance with human response. The p53+/- heterozygous mouse apparently identifies hormonal carcinogenic mechanisms, immunosuppressive carcinogens, and genotoxic carcinogens. The TG:AC predicts for rodent tumorigens applied topically. Recent experiences at FDA, CPMP, and MHW indicate that with good planning and agency interactions, regulatory acceptability can be anticipated.

  4. Bioavailability of iron from spinach using an in vitro/human Caco-2 cell bioassay model

    NASA Technical Reports Server (NTRS)

    Rutzke, Corinne J.; Glahn, Raymond P.; Rutzke, Michael A.; Welch, Ross M.; Langhans, Robert W.; Albright, Louis D.; Combs, Gerald F Jr; Wheeler, Raymond M.

    2004-01-01

    Spinach (Spinacia oleracea) cv Whitney was tested for iron bioavailabilty using an in vitro human intestinal cell culture ferritin bioassay technique previously developed. Spinach was cultured in a growth chamber for 33 days, harvested, and freeze-dried. Total iron in the samples was an average of 71 micrograms/g dry weight. Spinach was digested in vitro (pepsin and 0.1 M HCl followed by pancreatin and 0.1 M NaHCO3) with and without the addition of supplemental ascorbic acid. Caco-2 cell cultures were used to determine iron bioavailability from the spinach mixtures. Production of the iron-binding protein ferritin in the Caco-2 cells showed the supplemental ascorbic acid doubled bioavailability of iron from spinach. The data show fresh spinach is a poor source of iron, and emphasize the importance of evaluation of whole meals rather than single food items. The data support the usefulness of the in vitro/Caco-2 cell ferritin bioassay model for prescreening of space flight diets for bioavailable iron.

  5. Bioassay and characterization of soil microorganisms involved in the biodegradation of the fungicide, metalaxyl

    SciTech Connect

    Bailey, A.M.

    1985-01-01

    A sensitive bioassay was developed to detect low concentrations of metalaxyl in soils. The quantitative estimation of metalaxyl in soils was based on a significant positive relationship between the radial growth of Phytophthora boehmeriae and the log concentration of the fungicide in the agar. The isolate of P. boehmeriae was chosen for its sensitivity to metalaxyl as manifested in a linear growth response on cornmeal agar over a range of 2 to 30 ng/ml. The sensitivity and quantitative nature of the bioassay was confirmed by comparison with data obtained by using /sup 14/C-metalaxyl. Metabolism of metalaxyl was detected in three of five avocado soils that had repeated applications of the fungicide over 2-5 yr. The average disappearance of metalaxyl was 28 days, and in the most active soils was 14 days. The composition and level of the microbial populations of soils, either active or inactive in the breakdown of metalaxyl, did not differ. Fungal and bacterial microflora recovered from these two soils by use of either selective media or filtration techniques were capable of metabolizing metalaxyl over a 45-day period.

  6. Are tumor incidence rates from chronic bioassays telling us what we need to know about carcinogens?

    PubMed

    Gaylor, David W

    2005-03-01

    Chronic bioassays for over 500 chemicals have been conducted under the auspices of the National Cancer Institute and/or the National Toxicology Program (NTP) to screen chemicals for carcinogenicity, providing a wealth of information about bioassays. Typically, chemicals are administered for two years to both sexes in each of one strain of rats and mice generally at the maximum tolerated dose (MTD), MTD/2, MTD/4 (in recent years), as well as unexposed control animals. In an attempt to ascertain the sensitivity of this bioassay to detect animal carcinogens tested at the MTD for the current experimental design, the false negative rate (failure to detect increased tumor rates) was investigated. This was accomplished by examining the tumor incidences from over 150 NTP bioassays and estimating the probability that a statistically significant (P0.01) dose-response trend would be obtained at one or more tissue sites in either sex of rats or mice if 200, rather than 50, animals were used per dose group. This provides an estimate of the proportion of chemicals that were not declared high-dose animal carcinogens due to the limited sample size of 50 animals per species-sex-dose group. In this series of chemicals tested, 97/156 (62%) were identified by the NTP to show some or clear evidence of carcinogenicity. With an increase of the number of animals per dose group from 50 to 200, it is estimated that 92% of these chemicals would show statistically significant (P0.01) dose-response trends at one or more tissue sites in either sex of rats or mice. Many of these chemicals are not genotoxic. Some chemicals had no structural alerts for carcinogenicity, but were tested because of potentially high human exposure. This analysis suggests that almost all of the chemicals selected would produce a statistically significant increase in tumor incidence at the MTD with larger sample sizes. Hence, this MTD bioassay screen is not distinguishing between true carcinogens and non

  7. Comparative study of three oligochaete species as indicators of metals in a sediment toxicity bioassay

    SciTech Connect

    Chapman, K.; Scheuerman, P.; Lanza, G.; Nelson, D.; Brinkhurst, R.

    1995-12-31

    Three oligochaete species, Tubifex tubifex, Branchiura sowerbyi and Lumbriculus variegatus, were analyzed for bioaccumulation and reproductive effects from reference sediment spiked with Cd or Cu. Sediment was spiked using the Sediment Suspension method to achieve concentrations of 4.0, 8.0 and 16.0 mg Cd/kg sediment (dry weight) and 25.0, 36.0, 50.0, 100.0 mg Cu/kg sediment (dry weight) . The bioassay was conducted under aerated, static conditions for 28 d at 22.5 C. Reproductive effects consisting of number of cocoons and eggs produced a negative linear regression with increasing Cd concentration. Cocoon volume remained consistent. Cu was more toxic to T. tubifex in this bioassay than results reported by the USEPA using similar concentrations. Lower concentrations of Cu also showed a negative linear regression with reproductive effects showing that oligochaetes could be a feasible indicator organism for sediment toxicity in a standardized ecological impact assay using reproduction as an endpoint.

  8. DOSEXPRT: A bioassay dosimetry code for Martin Marietta Energy Systems, Inc

    SciTech Connect

    Ward, R.C.; Eckerman, K.F.

    1992-04-01

    The bioassay code DOSEXPRT was developed for Martin Marietta Energy Systems, Inc., to provide compliance with Department of Energy (DOE) Order 5480, Chapter 11. DOSEXPRT computes the intake of a radionuclide in any year (considering both acute and chronic intakes) from in vivo measurements of the retained activity and/or measurements of the activity in excreta. The committed effective and organ doses for the intake are computed as well as the effective and organ doses expected to be received in each calendar year out to 50 years beyond the year of intake. The bioassay records used as input for DOSEXPRT are extracted from the Martin Marietta Energy Systems Occupational Health Information System (OHIS). DOSEXPRT implements a set of algorithms with parameters governing the translocation, retention, and excretion of the nuclide contained in data files specific to the nuclide. These files also contain dose-per-unit-intake coefficients used to compute the committed dose equivalent for the intakes in the year. Annual organ and effective doses are computed using additional dose-rate files that contain data on the dose rate at various times following a unit intake. If measurements are presented for more than one assay for a given nuclide, DOSEXPRT estimates the intake by applying weights assigned in the nuclide file for each assay. DOSEXPRT is accessed off the OHIS MENU No. 4 and designed to be run as a batch processor, but can also be run interactively for testing purposes.

  9. DOSEXPRT: A bioassay dosimetry code for Martin Marietta Energy Systems, Inc.

    SciTech Connect

    Ward, R.C.; Eckerman, K.F.

    1992-04-01

    The bioassay code DOSEXPRT was developed for Martin Marietta Energy Systems, Inc., to provide compliance with Department of Energy (DOE) Order 5480, Chapter 11. DOSEXPRT computes the intake of a radionuclide in any year (considering both acute and chronic intakes) from in vivo measurements of the retained activity and/or measurements of the activity in excreta. The committed effective and organ doses for the intake are computed as well as the effective and organ doses expected to be received in each calendar year out to 50 years beyond the year of intake. The bioassay records used as input for DOSEXPRT are extracted from the Martin Marietta Energy Systems Occupational Health Information System (OHIS). DOSEXPRT implements a set of algorithms with parameters governing the translocation, retention, and excretion of the nuclide contained in data files specific to the nuclide. These files also contain dose-per-unit-intake coefficients used to compute the committed dose equivalent for the intakes in the year. Annual organ and effective doses are computed using additional dose-rate files that contain data on the dose rate at various times following a unit intake. If measurements are presented for more than one assay for a given nuclide, DOSEXPRT estimates the intake by applying weights assigned in the nuclide file for each assay. DOSEXPRT is accessed off the OHIS MENU No. 4 and designed to be run as a batch processor, but can also be run interactively for testing purposes.

  10. A bioassay for the detection of benzimidazoles reveals their presence in a range of environmental samples.

    PubMed

    Crofts, Terence S; Men, Yujie; Alvarez-Cohen, Lisa; Taga, Michiko E

    2014-01-01

    Cobamides are a family of enzyme cofactors that include vitamin B12 (cobalamin) and are produced solely by prokaryotes. Structural variability in the lower axial ligand has been observed in cobamides produced by diverse organisms. Of the three classes of lower ligands, the benzimidazoles are uniquely found in cobamides, whereas the purine and phenolic bases have additional biological functions. Many organisms acquire cobamides by salvaging and remodeling cobamides or their precursors from the environment. These processes require free benzimidazoles for incorporation as lower ligands, though the presence of benzimidazoles in the environment has not been previously investigated. Here, we report a new purification method and bioassay to measure the total free benzimidazole content of samples from microbial communities and laboratory media components. The bioassay relies on the "calcofluor-bright" phenotype of a bluB mutant of the model cobalamin-producing bacterium Sinorhizobium meliloti. The concentrations of individual benzimidazoles in these samples were measured by liquid chromatography-tandem mass spectrometry. Several benzimidazoles were detected in subpicomolar to subnanomolar concentrations in host-associated and environmental samples. In addition, benzimidazoles were found to be common contaminants of laboratory media components. These results suggest that benzimidazoles present in the environment and in laboratory media have the potential to influence microbial metabolic activities.

  11. Sediment bioassay with sago pondweed (Potamogeton pectinatus), a submersed aquatic macrophyte

    SciTech Connect

    Fleming, W.J.; Siesko, M.M.; Ailstock, M.S.

    1994-12-31

    Sago pondweed explants produced in tissue culture were grown for 6 weeks in sediments from Baltimore Harbor, MD. Although sediments contained up to 9,800 ppm Al, 7.5 ppm Cd, 3,090 ppm Cr, 397 ppm Pb, 530 Cu, 1,320 Sn, 2,040 ppm Zn, and 82,900 ppm oil and grease (all expressed as dry wt.) stepwise linear regression of log transformed contaminant data showed no linkage of reduced plant growth to the contaminants measured. Plant growth was negatively correlated with particle size and particle size was negatively correlated with most contaminant concentrations. In a second study, 17 estuarine sediments, representing a range of low to very high toxicity in Microtox and Hyalella azteca bioassays, were selected for study. Selected sediments contained up to 10 ppm Cd, 135 ppm Cr, 21 ppm Cu, 105 ppm Pb, 15 ppm Ni, and 190 ppm Zn (all expressed as dry wt.). Sago pondweed explants were planted into these sediments and grown for 4 weeks. Biomass production differed significantly among sediments tested. Phytotoxicity of sediments did not correlate well with the toxicity results of the Microtox and Hyalella azteca bioassays nor the metal content of sediments.

  12. Metal toxicity and biodiversity in serpentine soils: application of bioassay tests and microarthropod index.

    PubMed

    Visioli, Giovanna; Menta, Cristina; Gardi, Ciro; Conti, Federica Delia

    2013-01-01

    Eco-toxicological or bioassay tests have been intensively discussed as tools for the evaluation of soil quality. Tests using soil organisms, including microarthropods and plants, allow direct estimates to be made of important soil characteristics and functions. In this study we compared the results obtained by two in vitro standard bioassays following ISO or OECD guidelines: (i) the short term-chronic phytotoxicity germination and root elongation test using three different plant species Cucumis sativus L. (Cucurbitaceae), Lepidium sativum L. (Brassicaceae), and Medicago sativa L. (Fabaceae) and (ii) the inhibition of reproduction of Folsomia candida (Collembola) by soil pollutants to investigate the toxicity of a serpentine soil present in the Italian Apennines, rich in heavy metals such as Ni, Cr, and Co. In addition, microarthropod communities were characterised to evaluate the effects of metal contents on the soil fauna in natural conditions. Abundances, Acari/Collembola ratio, biodiversity indices and the QBS-ar index were calculated. Our results demonstrate that the two in vitro tests distinguish differences correlated with metal and organic matter contents in four sub-sites within the serpentinite. Soil fauna characterisation, not previously performed on serpentine soils, revealed differences in the most vulnerable and adapted groups of microarthropods to soil among the four sub-sites: the microarthropod community was found to be rich in term of biodiversity in the sub-site characterised by a lower metal content and a higher organic matter content and vegetation.

  13. A Novel in vitro Bioassay to Explore the Repellent Effects of Compounds Against Mosquito Aedes aegypti (Diptera: Culicidae).

    PubMed

    Rehman, Junaid U; Tabanca, Nurhayat; Khan, Ikhlas A

    2016-01-01

    Mosquitoes are vectors for many pathogens resulting in many deaths of humans. Repellents play an important role in reducing mosquito bites and the spread of mosquito-borne diseases. Currently, Klun & Debboun (K & D) and human-arm-based bioassay systems are used to identify repellent properties of compounds, extracts, and essential oils. Risks involved with human-arm-based systems are allergic reactions and limited replicates. We are reporting an in vitro bioassay method “NCNPR repellent bioassay (NCNPR-RB)” that can closely simulate the results of the cloth patch bioassay system used to determine repellency against mosquitoes. The NCNPRRB method uses heat to attract mosquito and edible collagen sheets as an alternate to human skin. Multiple plant compounds with documented repellency were tested. DEET (N,N-diethyl-3-methylbenzamide) was used as a positive control. Treatments were prepared in EtOH and applied in dosages ranging from 0.011–1.5mg/cm2 to a 20-cm2 collagen sheet. The number of mosquitoes commencing to bite per probe was recorded visually for 1 min. The minimum effective dosage (mg/cm2) of compounds: DEET (0.021), carvacrol (0.011), thymol (0.013), undecanoic acid (0.023), thymol methyl ether (0.269), and 2-nonanone (>0.375 mg/cm2) determined in NCNPRRB were similar to those reported in literature using a cloth patch bioassay system. The NCNPR-RB can be used to screen compounds with reasonable reproducibility of the data at a faster rate than the cloth patch bioassay, which involves the use of human subjects.

  14. Filter extraction and Ames bioassay results for EPA (Environmental Protection Agency) particulate samples. Final report September 1983-May 1984

    SciTech Connect

    Warner-Selph, M.A.

    1984-08-01

    This report describes filter extractions and Ames bioassay of filter extracts performed for the Emission Control Technology Division of Environmental Protection Agency. Eight sets of particulate-loaded filters were provided to SwRI by the sponsor. The filters were soxhlet-extracted in methylene chloride, and the extracts were dried and weighed. The organic extracts were analyzed using the Ames bioassay at Southwest Foundation for Biomedical Research (SFBR), formerly Southwest Foundation for Research and Education. The data were analyzed using linear and non-linear regression methods.

  15. Trigger values for investigation of hormonal activity in drinking water and its sources using CALUX bioassays.

    PubMed

    Brand, Walter; de Jongh, Cindy M; van der Linden, Sander C; Mennes, Wim; Puijker, Leo M; van Leeuwen, Cornelis J; van Wezel, Annemarie P; Schriks, Merijn; Heringa, Minne B

    2013-05-01

    To screen for hormonal activity in water samples, highly sensitive in vitro CALUX bioassays are available which allow detection of estrogenic (ERα), androgenic (AR), progestagenic (PR), and glucocorticoid (GR) activities. This paper presents trigger values for the ERα, AR, PR, and GR CALUX bioassays for agonistic hormonal activities in (drinking) water, which define a level above which human health risk cannot be waived a priori and additional examination of specific endocrine activity may be warranted. The trigger values are based on 1) acceptable or tolerable daily intake (ADI/TDI) values of specific compounds, 2) pharmacokinetic factors defining their bioavailability, 3) estimations of the bioavailability of unknown compounds with equivalent hormonal activity, 4) relative endocrine potencies, and 5) physiological, and drinking water allocation factors. As a result, trigger values of 3.8ng 17β-estradiol (E2)-equivalents (eq)/L, 11ng dihydrotestosterone (DHT)-eq/L, 21ng dexamethasone (DEX)-eq/L, and 333ng Org2058-eq/L were derived. Benchmark Quotient (BQ) values were derived by dividing hormonal activity in water samples by the derived trigger using the highest concentrations detected in a recent, limited screening of Dutch water samples, and were in the order of (value) AR (0.41)>ERα (0.13)>GR (0.06)>PR (0.04). The application of trigger values derived in the present study can help to judge measured agonistic hormonal activities in water samples using the CALUX bioassays and help to decide whether further examination of specific endocrine activity followed by a subsequent safety evaluation may be warranted, or whether concentrations of such activity are of low priority with respect to health concerns in the human population. For instance, at one specific drinking water production site ERα and AR (but no GR and PR) activities were detected in drinking water, however, these levels are at least a factor 83 smaller than the respective trigger values, and

  16. In vivo genotoxicity of furan in F344 rats at cancer bioassay doses

    SciTech Connect

    Ding, Wei

    2012-06-01

    Furan, a potent rodent liver carcinogen, is found in many cooked food items and thus represents a human cancer risk. Mechanisms for furan carcinogenicity were investigated in male F344 rats using the in vivo Comet and micronucleus assays, combined with analysis of histopathological and gene expression changes. In addition, formamidopyrimidine DNA glycosylase (Fpg) and endonuclease III (EndoIII)-sensitive DNA damage was monitored as a measure of oxidative DNA damage. Rats were treated by gavage on four consecutive days with 2, 4, and 8 mg/kg bw furan, doses that were tumorigenic in 2-year cancer bioassays, and with two higher doses, 12 and 16 mg/kg. Rats were killed 3 h after the last dose, a time established as producing maximum levels of DNA damage in livers of furan-treated rats. Liver Comet assays indicated that both DNA strand breaks and oxidized purines and pyrimidines increased in a near-linear dose-responsive fashion, with statistically significant increases detected at cancer bioassay doses. No DNA damage was detected in bone marrow, a non-target tissue for cancer, and peripheral blood micronucleus assays were negative. Histopathological evaluation of liver from furan-exposed animals produced evidence of inflammation, single-cell necrosis, apoptosis, and cell proliferation. In addition, genes related to apoptosis, cell-cycle checkpoints, and DNA-repair were expressed at a slightly lower level in the furan-treated livers. Although a mixed mode of action involving direct DNA binding cannot be ruled out, the data suggest that furan induces cancer in rat livers mainly through a secondary genotoxic mechanism involving oxidative stress, accompanied by inflammation, cell proliferation, and toxicity. -- Highlights: ► Furan is a potent rodent liver carcinogen and represents a human cancer risk. ► Furan induces DNA damage in rat liver at cancer bioassay doses. ► Furan induces oxidative stress, inflammation and cell proliferation in rat liver. ► Expression of

  17. Use of viral promoters in mammalian cell-based bioassays: How reliable?

    PubMed Central

    Betrabet, Shrikant S; Choudhuri, Jyoti; Gill-Sharma, Manjit

    2004-01-01

    Cell-based bioassays have been suggested for screening of hormones and drug bioactivities. They are a plausible alternative to animal based methods. The technique used is called receptor/reporter system. Receptor/reporter system was initially developed as a research technique to understand gene function. Often reporter constructs containing viral promoters were used because they could be expressed with very 'high' magnitude in a variety of cell types in the laboratory. On the other hand mammalian genes are expressed in a cell/tissue specific manner, which makes them (i.e. cells/tissues) specialized for specific function in vivo. Therefore, if the receptor/reporter system is to be used as a cell-based screen for testing of hormones and drugs for human therapy then the choice of cell line as well as the promoter in the reporter module is of prime importance so as to get a realistic measure of the bioactivities of 'test' compounds. We evaluated two conventionally used viral promoters and a natural mammalian promoter, regulated by steroid hormone progesterone, in a cell-based receptor/reporter system. The promoters were spliced into vectors expressing enzyme CAT (chloramphenicol acetyl transferase), which served as a reporter of their magnitudes and consistencies in controlling gene expressions. They were introduced into breast cell lines T47D and MCF-7, which served as a cell-based source of progesterone receptors. The yardstick of their reliability was highest magnitude as well as consistency in CAT expression on induction by sequential doses of progesterone. All the promoters responded to induction by progesterone doses ranging from 10-12 to 10-6 molar by expressing CAT enzyme, albeit with varying magnitudes and consistencies. The natural mammalian promoter showed the most coherence in magnitude as well as dose dependent expression profile in both the cell lines. Our study casts doubts on use of viral promoters in a cell-based bioassay for measuring bioactivities of

  18. Effects of conidial densities and spray volume of Metarhizium anisopliae and Beauveria bassiana fungal suspensions on conidial viability, droplet size and deposition coverage in bioassay using a novel bioassay spray system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted to study the conidial viability during bioassay spray with different suspensions of Metarhizium anisopliae ATCC 62176 and Beauveria bassiana NI8, and to investigate the effects of conidial density and spray volume on the distribution of droplet size and deposit coverage us...

  19. Bioassay-guided isolation of prenylated xanthones and polycyclic acylphloroglucinols from the leaves of Garcinia nujiangensis.

    PubMed

    Xia, Zheng-Xiang; Zhang, Dan-Dan; Liang, Shuang; Lao, Yuan-Zhi; Zhang, Hong; Tan, Hong-Sheng; Chen, Shi-Lin; Wang, Xin-Hong; Xu, Hong-Xi

    2012-08-24

    Bioassay-guided fractionation of the acetone extract of the leaves of Garcinia nujiangensis resulted in the isolation of two new prenylated xanthones, nujiangexanthones A (1) and B (2), three new polycyclic polyprenylated acylphloroglucinols, nujiangefolins A-C (3-5), and 10 known related analogues. The structures of compounds 1-5 were elucidated by interpretation of their spectroscopic data. Compounds 3 and 4 are unusual polycyclic polyprenylated acylphloroglucinols in which the enol hydroxy group forms a six-membered ring with a benzene ring carbon. The compounds isolated were evaluated for their cytotoxic effects against 11 cancer cell lines and immortalized MIHA normal liver cells, and the test substances demonstrated selectivity toward the cancer cells. Isojacareubin (6) was found to be the most potent cytotoxic compound of those tested.

  20. Early-stage bioassay for monitoring radioactive contamination in living livestock.

    PubMed

    Yamaguchi, Toshiro; Sawano, Kaita; Kishimoto, Miori; Furuhama, Kazuhisa; Yamada, Kazutaka

    2012-12-01

    Soil samples from the ground surface and feces and blood from a mixed-breed male pig were collected on April 10, 2011 at a farm within 20 km of the Fukushima Daiichi nuclear power plant. The radioactivity of each sample was measured using a Ge semiconductor detector. Despite the fact that the pig had been fed non-contaminated imported feed, (131)I, (134)Cs and (137)Cs were detected in the feces, and (134)Cs and (137)Cs were detected in the blood clots. Because it is considerably difficult to measure radioactive contamination in the edible muscle of living livestock, bioassays are an option for the screening of radioactive contamination in living livestock to ensure food safety.

  1. Development of a chronic sublethal sediment bioassay using the estuarine amphipod Leptocheirus plumulosus (Shoemaker)

    SciTech Connect

    Emery, V.L. Jr.; Moore, D.W.; Gibson, A.B.; Gray, B.R.; Duke, B.M.; Wright, R.B.; Farrar, J.D.

    1997-09-01

    Based on the need for a test to evaluate chronic sublethal toxicity in estuarine sediments, a 28-d sediment bioassay with the estuarine amphipod, Leptocheirus plumulosus (Shoemaker) was developed. The test was initiated with animals less than 2 weeks old. Test endpoints included survival, growth, and reproduction. Factors with the potential to influence test animal performance such as artificial sea salts, salinity, food ration, size at test initiation, intraspecific density, sediment grain size, and diet were evaluated. For example, intraspecific densities between 10 and 60 animals/beaker did not affect survival, growth, or reproduction. Similarly, L. plumulosus were tolerant of a wide range of sediment grain sizes with only extremely fine grained or coarse grained material significantly affecting survival, growth, and reproduction. Test performance criteria included control survival (> 80%) and reproduction and response to a reference toxicant test with cadmium chloride in a control chart format.

  2. Turbidity as a method of preparing sperm dilutions in the echinoid sperm/egg bioassay

    SciTech Connect

    Hall, T.J.; Haley, R.K.; Battan, K.J. )

    1993-11-01

    The use of turbidimeter for preparing sperm dilutions used in the echinoid sperm/egg bioassay was evaluated. Regression analyses of the relationship between sperm density and turbidity for the sea urchins Strongylocentrotus purpuratus and Strongylocentrotus droebachiensis and the sand dollar Dendraster excentricus indicated that although there were slope differences for each species, each coefficient of determination was highly significant. For Dendraster excentricus, triplicate hemacytometer counts over a range of turbidities as well as repeated preparations of a single sperm turbidity indicated similar variability for each. The use of the turbidimeter has time-saving advantages over conventional hemacytometer methods without sacrificing precision. Sperm dilutions can be prepared rapidly, minimizing seawater sperm preactivation before test initiation, and may therefore contribute to increased test precision.

  3. Toxicity Appraisal of Untreated Dyeing Industry Wastewater Based on Chemical Characterization and Short Term Bioassays.

    PubMed

    Akhtar, Muhammad Furqan; Ashraf, Muhammad; Javeed, Aqeel; Anjum, Aftab Ahmad; Sharif, Ali; Saleem, Ammara; Akhtar, Bushra; Khan, Abdul Muqeet; Altaf, Imran

    2016-04-01

    Characterizing wastewaters only on a chemical basis may be insufficient owing to their complex nature. The purpose of this study was to assess toxicity of textile dyeing wastewater based on analytical techniques and short term toxicity based bioassays. In this study, screening of the fractionated wastewater through GC-MS showed the presence of phenols, phthalic acid derivatives and chlorpyrifos. Metal analysis revealed that chromium, arsenic and mercury were present in amounts higher than the wastewater discharge limits. Textile dyeing wastewater was found to be highly mutagenic in the Ames test. DNA damage in sheep lymphocytes decreased linearly with an increase in the dilution of wastewater. MTT assay showed that 8.3 percent v/v wastewater decreased cell survival percentage to 50 %. It can be concluded from this study that short term toxicity tests such as Ames test, in vitro comet assay, and cytotoxicity assays may serve as useful indicators of wastewater pollution along with their organic and inorganic chemical characterizations.

  4. Ecotoxicological assessment of metal-polluted urban soils using bioassays with three soil invertebrates.

    PubMed

    Santorufo, Lucia; Van Gestel, Cornelis A M; Maisto, Giulia

    2012-07-01

    This study aimed at assessing the quality of urban soils by integrating chemical and ecotoxicological approaches. Soils from five sites in downtown Naples, Italy, were sampled and characterized for physical-chemical properties and total and water-extractable metal concentrations. Bioassays with Eisenia andrei, Enchytraeus crypticus and Folsomia candida were performed to assess toxicity of the soils, using survival, reproduction and growth as the endpoints. Metal bioaccumulation in the animals was also measured. The properties and metal concentrations of the soils strongly differed. Metal bioaccumulation was related with total metal concentrations in soil and was highest in E. crypticus, which was more sensitive than E. andrei and F. candida. Responses of the three species to the investigated soils seemed due to both metal contamination and soil properties.

  5. Bio-assay Guided Isolation of Anti-cancer Compounds from Anthocephalus cadamba Bark.

    PubMed

    Kumar, Deepak; Tejaswi, Chilukuri; Rasamalla, Saiprasanna; Mallick, Sumana; Pala, Bikas C

    2015-08-01

    Anthocephalus cadamba, an important plant in the traditional system of medicine in India, is reported to possess anticancer activity. Guided by bio-assay tests using human colorectal (HCT116) and hepatocellular carcinoma (HepG2) cell lines, it has been shown to contain three active constituents, the triterpenoid saponins 3-O-[α-L-rhamnopyranosyl]-quinovic acid (1) and 3-O-[α-L-rhamnopyranosyl]-quinovic acid 28-O-[β-D-glucopyranosyl] ester (2), and the alkaloid cadambine (3). The structures of the isolated compounds were established using spectroscopic techniques. The isolated compounds demonstrated concentration dependent inhibition of both the cell lines, where compound 3 proved to be the most potent inhibitor of cell line HCT116 (IC50 45 +/- 4 μg/mL) and compound 2 demonstrated maximum inhibitory activity against HepG2 cell line with an IC50 value of 89 +/- 7 μg/mL.

  6. Evaluation of the toxic and genotoxic potential of landfill leachates using bioassays.

    PubMed

    Bortolotto, Tiago; Bertoldo, Jean Borges; da Silveira, Fernanda Zanette; Defaveri, Tamires Manganelli; Silvano, Jacira; Pich, Claus Tröger

    2009-09-01

    Landfill leachates are liquid effluents with elevated concentrations of chemical compounds that can cause serious environmental pollution. In the south of the state of Santa Catarina, Brazil, a sanitary landfill was installed that employs a system of anaerobic/facultative lagoons for the treatment of its leachate. The present work examined the toxic and genotoxic potential of untreated and treated landfill leachates using bioassays. The chemical, toxic, genotoxic and mutagenic properties of the untreated leachate and the treated leachate were determined. Examination of the chemical properties showed a marked decrease in parameters after treatment, as well as in toxicity towards all the organisms tested. The results of the comet assay demonstrated that both leachates showed genotoxicity in all of the organisms tested, indicating the persistence of genotoxic substances even after treatment. A significant decrease in micronucleated cells was detected in Geophagus brasiliensis exposed to the treated leachate compared to untreated.

  7. Harvester ant bioassay for assessing hazardous chemical waste sites. [Pogonomyrmex owhyeei

    SciTech Connect

    Gano, K.A.; Carlile, D.W.; Rogers, L.E.

    1985-05-01

    A technique was developed for using harvester ants, Pogonomyrmex owhyeei, in terrestrial bioassays. Procedures were developed for maintaining stock populations, handling ants, and exposing ants to toxic materials. Relative toxicities were determined by exposing ants to 10 different materials. These materials included three insecticides, Endrin, Aldrin, and Dieldrin; one herbicide, 2,4-D; three complex industrial waste residuals, wood preservative sludge, drilling fluid, and slop oil; and three heavy metals, copper zinc, and cadium. Ants were exposed in petri dishes containing soil amended with a particular toxicant. Under these test conditions, ants showed no sensitivity to the metals or 2,4-D. Ants were sensitive to the insecticides and oils in repeated tests, and relative toxicity remained consistent throughout. Aldrin was the most toxic material followed by Dieldrin, Endrin, wood preservative sludge, drilling fluid, and slop oil. 12 refs., 2 figs., 2 tabs.

  8. Comparison of the estrogenic potencies of standardized soy extracts by immature rat uterotrophic bioassay.

    PubMed

    de Lima Toccafondo Vieira, Manuela; Duarte, Rodrigo Ferreira; Campos, Ligia Maria Moreira; Nunan, Elzíria de Aguiar

    2008-01-01

    Soy phytoestrogens, isoflavones, are a primary class of plant-based estrogen alternatives being sold over the counter nowadays. Genistein, daidzein and glycitein are the major isoflavones found in soybeans, as aglycones and glycosides. Each isoflavone shows distinctive estrogenic activity and pharmacokinetics. Soy dry extracts, employed as pharmaceutical raw material for manufacturing isoflavone supplements, are standardized to contain 40% of total isoflavones, but the amount of each isoflavone is highly diverse. The influence of these compositional differences on the estrogenic potency of soy extracts was evaluated by uterotrophic bioassay. Five commercial samples of standardized soy dry extract, homogeneously suspended in arachis oil, were administered per os in serial doses (125-4150 mg/kg bw/day) to immature female rats for 3 days. Soy extract samples with considerable diversity in isoflavone composition revealed different estrogenic potencies. Our results indicate a need of standardization of the individual isoflavone content in soy extracts.

  9. Theobroma cacao: Review of the Extraction, Isolation, and Bioassay of Its Potential Anti-cancer Compounds

    PubMed Central

    Baharum, Zainal; Akim, Abdah Md; Hin, Taufiq Yap Yun; Hamid, Roslida Abdul; Kasran, Rosmin

    2016-01-01

    Plants have been a good source of therapeutic agents for thousands of years; an impressive number of modern drugs used for treating human diseases are derived from natural sources. The Theobroma cacao tree, or cocoa, has recently garnered increasing attention and become the subject of research due to its antioxidant properties, which are related to potential anti-cancer effects. In the past few years, identifying and developing active compounds or extracts from the cocoa bean that might exert anti-cancer effects have become an important area of health- and biomedicine-related research. This review provides an updated overview of T. cacao in terms of its potential anti-cancer compounds and their extraction, in vitro bioassay, purification, and identification. This article also discusses the advantages and disadvantages of the techniques described and reviews the processes for future perspectives of analytical methods from the viewpoint of anti-cancer compound discovery. PMID:27019680

  10. Enzyme activation of human prolactin: a potential basis for a bioassay.

    PubMed

    Ryle, M; Bertrand, P V

    1989-07-01

    Small cultures of human amniotic cells were preincubated for 24 h. Human prolactin was then added to the medium. After a further short period of incubation the tubes were chilled, the medium removed and the cells rinsed with saline. The tubes then received cold Tris-sucrose and were frozen, to disrupt the cells. After thawing, adenosine triphosphatase (ATPase) and p-nitrophenyl phosphatase (PNPase) were measured. Buffer was added containing either ATP or PNP and the tubes were incubated for 30 min. Inorganic phosphate released from ATP and p-nitrophenol was measured spectrophotometrically. Prolactin stimulated both enzyme activities. The ATPase log dose-response curve was linear between approximately 12.5 and 200 mIU/l. It was inhibited by ouabain. Isobutyl-1-methylxanthine inhibited the ATPase but not the alkaline phosphatase activity. One of these human amniotic cell enzymes may provide the basis for a sensitive bioassay for human prolactin.

  11. Environmental effects of dredging: Upland animal bioassays of dredged materials. Technical note

    SciTech Connect

    Simmers, J.W.; Rhett, R.G.; Lee, C.R.

    1986-01-01

    The Clean Water Act in the United States requires that the environmental evaluation of dredged material prior to discharge or impacting the waters of the United States include the effects of disposal on concentrations of contaminants through biological processes. This results in a need for Corps of Engineers districts to be able to predict the contamination of animals that may be associated with potential disposal alternatives: open-water disposal, upland disposal, and wetland creation. The following is a summary of the results of bioassay procedures using the earthworm Eisenia foetida to evaluate the potential contaminant mobility into soil-dwelling animals. These tests were derived from proposed Organization for European Common Development (OECD) and European Economics Commission (EEC) test procedures (evaluating the effects of new chemicals) and modified to consider accumulation and sublethal effects rather than toxicity.

  12. Skin compatibility of cyclodextrins and their derivatives: a comparative assessment using a corneoxenometry bioassay.

    PubMed

    Piel, G; Moutard, S; Uhoda, E; Pilard, F; Piérard, G E; Perly, B; Delattre, L; Evrard, B

    2004-05-01

    Few studies have been performed to assess the risk of skin damage by cyclodextrins (CD) and they have yielded contradictory results. The present study was conducted using the corneoxenometry bioassay on human stratum corneum to compare the skin compatibility of CD currently used in pharmaceutical preparations (betaCD, gammaCD, Rameb, Dimeb, Trimeb, HP-betaCD and HP-gammaCD) and that of new amphiphilic CD derivatives, namely, the phospholipidyl-CD (DMPE-Dimeb and DMPE-Trimeb). All the tested CD were well tolerated by the stratum corneum at a concentration of 5%. However, inter-individual reactivity was larger for DMPE-Dimeb, suggesting a more aggressive trend for this compound. Cutaneous Index of Mildness values obtained confirm that Dimeb is able to extract some skin components and shows that DMPE-Dimeb performs similarly.

  13. Veterinary drugs no longer need testing for carcinogenicity in rodent bioassays.

    PubMed

    Galer, D M; Monro, A M

    1998-10-01

    The putative carcinogenic risk to humans from ingestion of edible tissues containing traces of nongenotoxic veterinary drugs is so slight that the routine application of rodent cancer bioassays cannot be justified. This argument is based, first, on the pharmacological similarity of veterinary and human drugs: many of the latter that are carcinogenic to rodents have been deemed on mechanistic and/or potency grounds not to pose a cancer risk to humans. Second, the distribution of a veterinary drug through the target animal body before ingestion of a portion of edible tissue by humans days or weeks later means that the human dose from a residue is several orders of magnitude lower than the normal dose of human drugs. The dose of residue is also much lower than the exposure of humans to the most potent carcinogens.

  14. Methotrexate intercalated layered double hydroxides with the mediation of surfactants: Mechanism exploration and bioassay study.

    PubMed

    Dai, Chao-Fan; Tian, De-Ying; Li, Shu-Ping; Li, Xiao-Dong

    2015-12-01

    Methotrexatum intercalated layered double hydroxides (MTX/LDHs) hybrids were synthesized by the co-precipitation method and three kinds of nonionic surfactants with different hydrocarbon chain lengths were used. The resulting hybrids were then characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). XRD and FTIR investigations manifest the successful intercalation of MTX anions into the interlayer of LDHs. TEM graphs indicate that the morphology of the hybrids changes with the variation of the chain length of the surfactants, i.e., the particles synthesized using polyethylene glycol (PEG-7) present regular disc morphology with good monodispersity, while samples with the mediation of alkyl polyglycoside (APG-14) are heavily aggregated and samples with the addition of polyvinylpyrrolidone (PVP-10) exhibit irregular branches. Furthermore, the release and bioassay experiments show that monodisperse MTX/LDHs present good controlled-release and are more efficient in the suppression of the tumor cells.

  15. Evaluation of the toxic and genotoxic potential of acid mine drainage using physicochemical parameters and bioassays.

    PubMed

    Netto, E; Madeira, R A; Silveira, F Z; Fiori, M A; Angioleto, E; Pich, C T; Geremias, R

    2013-05-01

    Carboniferous activity generates acid mine drainage (AMD) which is capable of unleashing toxic effects on the exposed biota. The aim of this study was to evaluate the toxic and genotoxic potential of untreated-AMD and AMD treated with calcinated sediment, using physicochemical parameters and bioassays. Results revealed that untreated-AMD presented low pH values and elevated concentrations of the metals Fe, Al, Mn, Zn and Cu. High acute toxicity was observed in Artemia sp. and Daphnia magna, and sub-chronic toxicity and genotoxicity in Allium cepa L. as well as scission of plasmid DNA exposed to untreated-AMD. Treatment of AMD with calcinated sediment promoted the reduction of acidity and the removal of metals, as well as a reduction in toxic and genotoxic effects. In conclusion, the calcinated sediment can be used as an alternative AMD treatment.

  16. Incidence of ketamine-induced emesis in cynomologus monkeys (Macaca fascicularis) used for staphylococcal enterotoxin bioassay.

    PubMed Central

    Adesiyun, A. A.; Tatini, S. R.

    1982-01-01

    Ten (24%) of 41 cynomologus monkeys (Macaca fascicularis) showed emetic response to 2.5-20 mg/Kg of ketamine injected i.m. Reduction of the levels of ketamine to one half or less of the emetic level resulted in faster recovery from sedation yet provided adequate time for intubation and subsequent intragastric feeding of staphylococcal enterotoxin (SE) in only 6 of the 10 monkeys without emesis. The onset of the first emetic episode with ketamine was similar to that induced by staphylococcal enterotoxin A (SEA). Cynomologus monkeys showing emetic response to ketamine could still be used for SE bioassay if an experimentally determined non-emetic dose for individual monkeys is employed for sedation. PMID:7093145

  17. Bioassay of Dibutyltin Diacetate for Possible Carcinogenicity (CAS No. 1067-33-0).

    PubMed

    1979-01-01

    Dibutyltin diacetate, a widely used catalyst for polymerization reactions, was selected for bioassay by the National Cancer Institute in an effort to screen a number of organo-metallic compounds for carcinogenicity. A bioassay for the possible carcinogenicity of dibutyltin diacetate was conducted using Fischer 344 rats and B6C3F1 mice. Dibutyltin diacetate was administered in the feed, at either of two concentrations, to groups of 50 male and female animals of each species. Twenty animals of each sex and species were placed on test as controls. The high and low time-weighted average dietary concentrations of dibutyltin diacetate were, respectively, 133 and 66.5 ppm for rats and 152 and 76 ppm for mice. The compound was administered for 78 weeks to rats and mice, followed by a period of no compound administration of 26 weeks for rats and 14 weeks for mice. There were significant positive associations between the concentrations of dibutyltin diacetate administered and mortality in male rats and female mice. There were no significant positive associations between the concentrations administered and mortality in female rats or male mice. Adequate numbers of animals in all groups survived sufficiently long to be at risk from late-developing tumors. Mean body weight depression, relative to controls, was observed in male mice and significantly accelerated mortality, relative to controls, was observed in male rats and female mice, indicating that the concentrations of dibutyltin diacetate administered to these animals may have approximated the maximum tolerated concentrations. Since no mean body weight depression, no significantly accelerated mortality, and no other signs of toxicity were associated with administration of dibutyltin acetate to femalerats, it is possible that these animals may have been able to tolerate a higher dietary concentration. There were no neoplasms occurring in statistically significant higher incidences in dosed rats or mice when compared to

  18. Respiratory tract clearance model for dosimetry and bioassay of inhaled radionuclides

    SciTech Connect

    Bailey, M.R.; Birchall, A. ); Cuddihy, R.G. ); James, A.C. ); Roy, M. . Inst. de Protection et de Surete Nucleaire)

    1990-07-01

    The ICRP Task Group on Respiratory Tract Models is developing a model to describe the retention and clearance of deposited radionuclides for dose-intake calculations and interpretation of bioassay data. Clearance from each region is treated as competition between mechanical transport, which moves particles to the gastro-intestinal tract and lymph nodes, and the translocation of material to blood. It is assumed that mechanical transport rates are the same for all materials, and that rates of translocation to blood are the same in all regions. Time-dependent clearance is represented by combinations of compartments. Representative values of parameters to describe mechanical transport from the human respiratory tract have been estimated, and guidance is given on the determination of translocation rates. It is emphasized that the current version of the model described here is still provisional. 30 refs.

  19. Correlation and comparison of Nb/sub 2/ lymphoma cell bioassay with radioimmunoassay for human prolactin

    SciTech Connect

    Subramanian, M.G.; Spirtos, N.J.; Moghissi, K.S.; Magyar, D.M.; Hayes, M.F.; Gala, R.R.

    1984-12-01

    Serum samples from groups of men and women with normal and elevated prolactin (PRL) levels were assayed by radioimmunoassay (RIA) and by Nb/sub 2/ lymphoma cell bioassay (BA) for the presence of PRL. Because the Nb/sub 2/ lymphoma cells respond to both PRL and growth hormone, BA for PRL activity was carried out before and after neutralization of growth hormone in the serum samples. There were excellent correlations between RIA and BA both in euprolactinemic and hyperprolactinemic subjects. On an absolute basis, RIA and BA values were similar in the euprolactinemic group (6.6 +/- 0.8 versus 6.2 +/- 1.0), whereas in the hyperprolactinemic group, RIA values were significantly higher than the BA results. The two assay systems also appeared to correlate better in women who were hyperprolactinemic, with obvious menstrual cycle disturbances, than in hyperprolactinemic women without menstrual cycle disturbances.

  20. Bioassay technique using nonspecific esterase activities of Tetrahymena pyriformis for screening and assessing cytotoxicity of xenobiotics

    SciTech Connect

    Bogaerts, P.; Senaud, J.; Bohatier, J. |

    1998-08-01

    A simple and rapid test for screening and assessing the cytotoxicity of xenobiotics was developed with Tetrahymena pyriformis. The method estimates the activities of nonspecific esterases of a cell by concentrating within it a specific amount of fluorescence associated with fluorescein dye. The 2-h median effective concentration (EC50) values of 10 inorganic and eight organic substances are presented and compared to those of three other bioassays: the conventional T. pyriformis proliferation rate 9-h median inhibitory concentrations, the Microtox 30-min EC50s, and the Daphnia magna 4-methylumbelliferyl {beta}-D galactoside 1-h EC50s. A highly significant correlation was found between the results obtained with the fluorescein diacetate test and those obtained with the growth inhibition and Microtox tests. This in vivo enzymatic test showed high sensitivity to all compounds tested except Cr{sup 6+} and sodium dodecyl sulfate.

  1. The pulmonary toxicity of talc and granite dust as estimated from an in vivo hamster bioassay.

    PubMed

    Beck, B D; Feldman, H A; Brain, J D; Smith, T J; Hallock, M; Gerson, B

    1987-02-01

    A short-term animal bioassay was used to assess the toxicity of occupational dusts. We quantified pulmonary responses in hamsters exposed to granite (12% quartz) and talc (quartz and asbestos-free) dust collected from worksites. Personal samples collected on workers showed similar quartz content and particle-size distributions to the high-volume samples collected for bioassays, thus demonstrating that the particulates were representative of worker exposure. We measured biochemical and cellular indicators of injury in bronchoalveolar lavage fluid (BAL) of animals exposed to dust suspensions by intra-tracheal instillation. The assays measured release of cytoplasmic and lysosomal enzymes into the cell-free supernatant of BAL; levels of albumin and red blood cells; changes in macrophage and polymorphonuclear neutrophil cell numbers; and in situ macrophage phagocytosis. Dose-response (0.15, 0.75, and 3.75 mg/100 g body wt) and time-course (1-14 days postexposure) studies were performed. One day after exposure, both talc and granite dust resulted in elevated enzyme levels, pulmonary edema, and increased cell numbers in BAL. Macrophage phagocytosis was also inhibited. Based on earlier studies, response levels were either intermediate between nontoxic iron oxide and toxic alpha-quartz or comparable with alpha-quartz. The response to granite dust diminished fairly rapidly over time. By contrast, after talc exposure, there was a more persistent elevation in enzyme levels, and macrophage phagocytosis remained depressed. These results indicate that, when a similar mass was deposited in the lungs, talc caused more lung injury than did granite. Better estimates of exposure-dose relationships in talc and granite workers as well as longer-term animal studies are required to evaluate the harmfulness of these work environments at present-day exposure levels.

  2. Toxicity of some bis Mannich bases and corresponding piperidinols in the brine shrimp (Artemia salina) bioassay.

    PubMed

    Gul, H Inci; Gul, Mustafa; Erciyas, Ercin

    2003-01-01

    Some acetophenone-derived bis Mannich bases were synthesized: bis[beta-benzoylethyl]ethylamine hydrochloride (IIa), bis[beta-(p-methylbenzoyl)ethyl]ethylamine hydrochloride (IIb), bis[beta-(p-chlorobenzoyl)ethyl]ethy- lamine hydrochloride (IId), bis[(2-thienylcarbonyl)ethyl]ethylamine hydrochloride (IIe); some corresponding piperidinol derivatives: 3-benzoyl-1-ethyl-4-phenyl-4-piperidinol hydrochloride (IIIa), 1-ethyl-3-(p-methyl- benzoyl)-4-(p-methylphenyl)-4-piperidinol hydrochloride (IIIb), 1-ethyl-3-(p-methoxybenzoyl)-4-(p-methoxy- phenyl)-4-piperidinol hydrochloride (IIIc), 1-ethyl-3-(p-chlorobenzoyl)-4-(p-chlorophenyl)-4-piperidinol hydrochloride (IIId), 1-ethyl-4-(2-thienyl)-3-(2-thienylcarbonyl)-4-piperidinol hydrochloride (IIIe); and some representative quaternary piperidinols: 3-benzoyl-1-ethyl-4-hydroxy-1-methyl-4-phenylpiperidinium iodide (IIIf), 1-ethyl-4-hydroxy-1-methyl-3-(p-methylbenzoyl)-4-(p-methylphenyl)piperidinium iodide (IIIg). Toxicity was tested by the brine shrimp bioassay as an intermediate test before further in vivo animal experiments. Piperidine derivatives were found to be more potent than bis Mannich bases. Quaternary piperidine derivatives IIIf and IIIg and also non-quaternary piperidine derivatives IIIb, IIIe, IIIc and IIId were more toxic than 5-fluorouracil in brine shrimp bioassay. Except for IIe, bis Mannich bases were not effective. Quaternization and conversion of bis Mannich bases to corresponding piperidines improved the toxicity. The lipid solubility of the compounds may not affect the toxicity. From these findings the quaternary piperidine derivatives IIIf and IIIg could be used in further drug development and also for in vivo experiments.

  3. Influence of light in acute toxicity bioassays of imidacloprid and zinc pyrithione to zooplankton crustaceans.

    PubMed

    Sánchez-Bayo, Francisco; Goka, Kouichi

    2006-06-30

    The acute toxicity of imidacloprid, a neonicotinoid insecticide, and zinc pyrithione (Zpt), a biocide used in anti-dandruff shampoos and protective antifouling paints, to three species of ostracods and two waterfleas, including Daphnia magna, was determined and compared under light and dark conditions. Under normal laboratory conditions, UV light had no significant influence on the outcome of toxicity bioassays, although in the case of imidacloprid both EC(50) and LC(50) calculated values were twice as high under the light as in the dark. No influence of UV light was observed on bioassays conducted with Zpt, in spite of the fast aqueous photolysis exhibited by this compound. Imidacloprid 48-h LC(50) for cladocerans (65-133mg/L) were two orders of magnitude higher than for ostracods (301-715microg/L); values of EC(50) for cladocerans and ostracods were 2-6mg/L and 3-16microg/L, respectively. Toxicity of Zpt to both ostracod and cladoceran species appears to be similar, with 48-h LC(50) in the range 137-524 and 75-197microg/L for ostracods and cladocerans, respectively, and similar values for EC(50)s. The mortality endpoint (LC(50)), however, is not a reliable predictor of the effects of imidacloprid under field situations (e.g. rice paddies), because the paralysis effect induced by this insecticide takes place at much lower concentrations than those required to cause the death of the animals: regardless of the taxa, differences as large as 100- or 600-fold were observed between the EC(50) and LC(50) for the same exposures. As a consequence, immobilization tests and EC(50) values are recommended for this class of compounds, while caution should be exercised in environmental risk assessments of this and possibly other related neonicotinoid insecticides with similar activity.

  4. Bioassays and selected chemical analysis of biocide-free antifouling coatings.

    PubMed

    Watermann, B T; Daehne, B; Sievers, S; Dannenberg, R; Overbeke, J C; Klijnstra, J W; Heemken, O

    2005-09-01

    Over the years several types of biocide-free antifouling paints have entered the market. The prohibition of biocidal antifouling paints in special areas of some European countries such as Sweden, Denmark and Germany has favoured the introduction of these paints to the market. Several types of biocide-free antifouling paints were subjected to bioassays and selected chemical analysis of leachate and incorporated substances. Both non-eroding coatings (silicones, fibre coats, epoxies, polyurethane, polyvinyl) and eroding coatings (SPCs, ablative) were tested to exclude the presence of active biocides and dangerous compounds. The paints were subjected to the luminescent bacteria test and the cypris larvae settlement assay, the latter delivering information on toxicity as well as on efficacy. The following chemical analyses of selected compounds of dry-film were performed: The results of the bioassays indicated that none of the coatings analysed contained leachable biocides. Nevertheless, some products contained or leached dangerous compounds. The analyses revealed leaching of nonylphenol (up to 74.7 ng/cm2/d after 48 h) and bisphenol A (up to 2.77 ng/cm2/d after 24 h) from epoxy resins used as substitutes for antifouling paints. The heavy metal, zinc, was measured in dry paint film in quantities up to 576,000 ppm in erodable coatings, not incorporated as a biocide but to control the rate of erosion. Values for TBT in silicone elutriates were mostly below the detection limit of 0.005 mg/kg. Values for DBT ranged between <0.005 and 6.28 mg/kg, deriving from catalysts used as curing agents. Some biocide-free paints contained leachable, toxic and dangerous compounds in the dry film, some of which may act as substitutes for biocides or are incorporated as plasticizers or catalysts. Implications to environmental requirements and legislation are discussed.

  5. Synthetic grape volatiles attract mated Lobesia botrana females in laboratory and field bioassays.

    PubMed

    Anfora, Gianfranco; Tasin, Marco; De Cristofaro, Antonio; Ioriatti, Claudio; Lucchi, Andrea

    2009-09-01

    In laboratory experiments, we identified and quantified volatiles emitted by inflorescences and berries of two grape varieties (Trebbiano and Sangiovese) and examined the effects of the volatiles on oviposition by the grapevine moth Lobesia botrana. Compared to Trebbiano, Sangiovese is relatively more susceptible to L. botrana infestations under natural conditions. Chemical and electrophysiological analysis indicated only quantitative differences between the volatiles released by the two varieties. In a dual-choice oviposition bioassay based only on volatile cues, females did not show any preference between the two varieties. The six major components of the odor profiles that were GC-EAD-active to female antennae included: limonene, 4,8-dimethyl-1,(E)-3,7-nonatriene, (+/-)-linalool, (E)-caryophyllene, (E,E)-alpha-farnesene, and methyl salicylate. At the beginning of the berry touch phenological stage, their proportions were about 10:0.6:0.4:0.5:0.9:0.6 in Trebbiano and 10:1:0.4:1.5:0.4:0.3 in Sangiovese. A six-component synthetic lure (with the proportion 10:1:1:1:1:1, which approximated the ratio of components released by both varieties) was used in further laboratory oviposition bioassays. Depending on its dosage, the synthetic lure either attracted or repelled oviposition. L. botrana females laid significantly more eggs in the presence of either the grape bunches or the synthetic lure at the attractive dosage. In a release-capture experiment conducted in a field cage that covered two grapevine rows, the synthetic lure was more attractive than a grape cluster or a blank control, and it stimulated oviposition on the vegetation near the lure. The results indicate that L. botrana uses olfactory cues to select oviposition sites and that an artificial lure, containing the major volatiles released by two grape varieties, may be useful in monitoring female activity in the field.

  6. Reusable optical bioassay platform with permeability-controlled hydrogel pads for selective saccharide detection.

    PubMed

    Cheung, Kwan Yee; Mak, Wing Cheung; Trau, Dieter

    2008-01-28

    A reusable optical bioassay platform using permeability-controlled hydrogel pads for selective saccharide detection has been developed. An optical glucose detection assay based on fluorescence resonance energy transfer (FRET) between dye-labeled dextran and Concanavalin A (ConA) was incorporated into hydrogel pads by entrapment. The hydrogel pads are constructed from hemispherical hydrogel attached onto hydrophobic surfaces of a microtiter plate. The resulted hemispherical hydrogel pads entrapping the sensing biological materials were further surface coated with polyelectrolyte multilayers through a Layer-by-Layer (LbL) self-assembly process to create a permeability-controlled membrane with nanometer thickness. The selective permeable LbL film deposited on the hydrogel surface allows small molecular weight analytes to diffuse into the hydrogel pads while the large molecular weight sensing biological molecules are immobilized. An encapsulation efficiency of 75% for the ConA/Dextran complex within the coated hydrogel pads was achieved and no significant leakage of the complex was observed. Glucose calibration curve with linear range from 0 to 10mM glucose was obtained. Selective permeability of the hydrogel pads has been demonstrated by measurement of saccharides with various molecular weights. The LbL hydrogel pads could selectively detect monosaccharides (glucose, MW=180) and disaccharides (sucrose, MW=342) while polysaccharides (dextran, MW approximately 70kDa) cannot diffuse through the LbL layer and are excluded. LbL hydrogel pads allow regeneration of the FRET system with good signal reproducibility of more than 90% to construct a reusable and reagentless optical bioassay platform.

  7. An Integrated Experimental Design for the Assessment of Multiple Toxicological End Points in Rat Bioassays

    PubMed Central

    Manservisi, Fabiana; Marquillas, Clara Babot; Buscaroli, Annalisa; Huff, James; Lauriola, Michelina; Mandrioli, Daniele; Manservigi, Marco; Panzacchi, Simona; Silbergeld, Ellen K.; Belpoggi, Fiorella

    2016-01-01

    Background: For nearly five decades long-term studies in rodents have been the accepted benchmark for assessing chronic long-term toxic effects, particularly carcinogenicity, of chemicals. The European Food Safety Authority (EFSA) and the World Health Organization (WHO) have pointed out that the current set of internationally utilized test methods capture only some of the potential adverse effects associated with exposures to these agents over the lifetime. Objectives: In this paper, we propose the adaption of the carcinogenicity bioassay to integrate additional protocols for comprehensive long-term toxicity assessment that includes developmental exposures and long-term outcomes, capable of generating information on a broad spectrum of different end points. Discussion: An integrated study design based on a stepwise process is described that includes the priority end points of the Economic Co-operation and Development and the National Toxicology Program guidelines on carcinogenicity and chronic toxicity and developmental and reproductive toxicity. Integrating a comprehensive set of relevant toxicological end points in a single protocol represents an opportunity to optimize animal use in accordance with the 3Rs (replacement, reduction and refinement). This strategy has the potential to provide sufficient data on multiple windows of susceptibility of specific interest for risk assessments and public health decision-making by including prenatal, lactational, neonatal exposures and evaluating outcomes over the lifespan. Conclusion: This integrated study design is efficient in that the same generational cohort of rats used for evaluating long-term outcomes can be monitored in satellite parallel experiments to measure biomarkers and other parameters related to system-specific responses including metabolic alterations and endocrine disturbances. Citation: Manservisi F, Babot Marquillas C, Buscaroli A, Huff J, Lauriola M, Mandrioli D, Manservigi M, Panzacchi S, Silbergeld

  8. Development and validation of a new fluorescence-based bioassay for aquatic macrophyte species.

    PubMed

    Küster, Anette; Altenburger, Rolf

    2007-02-01

    Bioassays with unicellular algae are frequently used as ecotoxicological test systems to evaluate the toxicity of contaminated environmental samples or chemicals. In contrast, aquatic macrophyte test systems are still rarely used as they are laborious to handle because species exhibit distinct ecological requirements. The aim of this study was to establish a fast and reproducible measuring system for aquatic macrophyte species to overcome those limitations for use. Thus, a newly developed pulse-amplitude modulated chlorophyll fluorometer (Imaging-PAM) was applied as an effect detection in short-term bioassays with aquatic macrophyte species. This multiwell-plate-based measuring device enables the incubation and measurement of up to 24 samples in parallel. The Imaging-PAM was used (i) to establish and validate the sensitivity of the test systems to three Photosystem II (PSII) inhibitors (atrazine, prometryn, isoproturon), (ii) to compare the test systems with established biotests for macrophytes and (iii) to define necessary time scales in aquatic macrophyte testing. The results showed that fluorescence-based measurements with the Imaging-PAM allow rapid and parallel analysis of large amounts of aquatic macrophyte samples and of toxicants effects of the PSII inhibitors tested on aquatic macrophytes. Measurements revealed a good correlation between obtained median effective concentrations (EC50s) for the new and the established biotest systems. Hence, the Imaging-PAM measuring device is a promising tool to allow fast chemical effect screening for high amounts of samples with little time and material and thus offers scope for high-throughput biotesting using aquatic macrophyte species.

  9. A standardisation of Ciona intestinalis (Chordata, Ascidiacea) embryo-larval bioassay for ecotoxicological studies.

    PubMed

    Bellas, Juan; Beiras, Ricardo; Vázquez, Elsa

    2003-11-01

    A standardisation of the ascidian Ciona intestinalis embryo-larval bioassay for marine pollution assessment has been developed. The minimum percentage of embryogenesis success was established to assess the quality of the biological material used; minimum sample size and number of replicates per treatment were also estimated. The suitability of artificial and natural seawater for the incubation of ascidian embryos and larvae was compared, and the optimum conditions of temperature, salinity, pH, density of embryos in the vials and the sperm/egg ratio were investigated. On the basis of the 10th percentile of the distribution of larval abnormalities, we proposed a threshold of 50% normal larvae in the control in order to consider the test of acceptable biological quality. According to our results n=5 is a sufficiently high replication to detect 5% differences among treatment means with a power of P=90% and alpha=0.05, and a sampling size >/=222 allows a 95% confidence in the estimate with an error of 0.05. Egg density did not affect larval development within the range 1-20 eggs/ml, and the optimum sperm/egg ratio which fertilise 100% of the eggs was 3000-30,000 sperm/egg (i.e. 10(8)-10(7) sperm/ml). There were not significant differences between the two water types tested, and the optimum tolerance ranges were 18-23 degrees C temperature, 34-42 ppt salinity (42 ppt was the highest salinity tested), and 7.4-8.8 pH. The median effective concentration (EC(50)) of copper (Cu) causing a 50% reduction of normal hatched larvae was 54.2 microg/l (0.85 microM), which shows a sensitivity of this species similar to the commonly used bivalve and sea-urchin tests. The ascidian embryo-larval bioassay is an accurate, reliable, simple and rapid method that can be used in ecotoxicological studies.

  10. Validation of the REA bioassay to detect estrogenic activity in the water cycle.

    PubMed

    Nguyen, Mai Thao; van der Oost, Ron; Bovee, Toine F H

    2011-12-01

    Endocrine disrupting compounds (EDCs) with estrogenic potency contaminate water and might eventually cause adverse effects to the aquatic environment. Many estrogenic compounds are not completely removed by wastewater treatment systems and, together with the run-off from agricultural areas, they enter surface waters. Chemical analytical methods to determine these compounds are usually expensive and laborious. Therefore, screening bioassays which are able to detect compounds based on their effects offer a solution for prior selection of samples that need to be chemically analyzed. In this study, the REA (RIKILT yeast Estrogen bioAssay), which has been developed to detect estrogenic compounds in calf urine and animal feed at RIKILT, is validated at the Water Board Laboratory of Waterproef for water samples. According to EC Decision 2002/657, detection capability CCβ, specificity and stability have to be determined for the internal validation of a qualitative screening test. In addition, surface water and effluent samples were analyzed to further demonstrate the applicability of the validated test procedure. Results demonstrate that the REA assay is reproducible and specific for estrogenic compounds in water and meets the criteria as prescribed in EC Decision 2002/657. The assay was sensitive enough to detect estrogenic activity of pollutants in water with a limit of quantification (LOQ) below 1 ng EEQ/L. This means that samples can be compared with preliminary threshold levels for drinking water and surface waters (7 and 1 ng EEQ/L, respectively). The stability of estrogenic activity in water samples is at least 4 weeks, when stored at 4 °C.

  11. A Novel Bioassay for the Activity Determination of Therapeutic Human Brain Natriuretic Peptide (BNP)

    PubMed Central

    Yu, Lei; Rao, Chunming; Shi, Xinchang; Li, Yonghong; Gao, Kai; Li, Xuguang; Wang, Junzhi

    2012-01-01

    Background Recombinant human brain natriuretic peptide (rhBNP) is an important peptide-based therapeutic drug indicated for the treatment of acute heart failure. Accurate determination of the potency of therapeutic rhBNP is crucial for the safety and efficacy of the drug. The current bioassay involves use of rabbit aortic strips, with experiments being complicated and time-consuming and markedly variable in results. Animal-less methods with better precision and accuracy should be explored. We have therefore developed an alternative cell-based assay, which relies on the ability of BNP to induce cGMP production in HEK293 cells expressing BNP receptor guanylyl cyclase-A. Methodology/Principal Findings An alternative assay based on the measurement of BNP-induced cGMP production was developed. Specifically, the bioassay employs cells engineered to express BNP receptor guanylyl cyclase-A (GCA). Upon rhBNP stimulation, the levels of the second messager cGMP in these cells drastically increased and subsequently secreted into culture supernatants. The quantity of cGMP, which corresponds to the rhBNP activity, was determined using a competitive ELISA developed by us. Compared with the traditional assay, the novel cell-based assay demonstrated better reproducibility and precision. Conclusion/Significance The optimized cell-based assay is much simpler, more rapid and precise compared with the traditional assay using animal tissues. To our knowledge, this is the first report on a novel and viable alternative assay for rhBNP potency analysis. PMID:23185490

  12. Differential immunoreactivity of goat derived scrapie following in vitro misfolding versus mouse bioassay.

    PubMed

    Madsen-Bouterse, Sally A; Zhuang, Dongyue; O'Rourke, Katherine I; Schneider, David A

    2012-07-13

    The protein misfolding cyclic amplification (PMCA) assay allows for detection of prion protein misfolding activity in tissues and fluids from sheep with scrapie where it was previously undetected by conventional western blot and immunohistochemistry assays. Studies of goats with scrapie have yet to take advantage of PMCA, which could aid in discerning the risk of transmission between goats and goats to sheep. The aim of the current study was to adapt PMCA for evaluation of scrapie derived from goats. Diluted brain homogenate from scrapie-infected goats (i.e., the scrapie seed, PrP(Sc)) was subjected to PMCA using normal brain homogenate from ovinized transgenic mice (tg338) as the source of normal cellular prion protein (the substrate, PrP(C)). The assay end-point was detection of the proteinase K-resistant misfolded prion protein core (PrP(res)) by western blot. Protein misfolding activity was consistently observed in caprine brain homogenate diluted 10,000-fold after 5 PMCA rounds. Epitope mapping by western blot analyses demonstrated that PrP(res) post-PMCA was readily detected with an N-terminus anti-PrP monoclonal antibody (P4), similar to scrapie inoculum from goats. This was in contrast to limited detection of PrP(res) with P4 following mouse bioassay. The inverse was observed with a monoclonal antibody to the C-terminus (F99/97.6.1). Thus, brain homogenate prepared from uninoculated tg338 served as an appropriate substrate for serial PMCA of PrP(Sc) derived from goats. These observations suggest that concurrent PMCA and bioassay with tg338 could improve characterization of goat derived scrapie.

  13. Bioassay of Phenol for Possible Carcinogenicity (CAS No.108-95-2).

    PubMed

    1980-08-01

    Phenol ranked 38th in production among U.S. chemicals in 1978 with annual production of 2.38 billion pounds. Approximately 90% of the phenol produced is used in the manufacture of phenolic (phenol formaldehyde) resins, caprolactam, bisphenol A, alkyl phenol, and adipic acid. The remainder of the phenol is used to produce an assortment of end products, including salicylic acid, phenacetin, dyes, metal cleaners, disinfectants, antiseptics, photographic chemicals, wood preservatives (pentachlorophenol), paints, paint and varnish removers, and agricultural chemicals (2,4-D and parathion). A bioassay of phenol to test for possible carcinogenicity was conducted by providing this substance in drinking water to F344 rats and B6C3F1 mice. Groups of 50 rats and 50 mice of each sex were given drinking water containing 2,500 or 5,000 ppm phenol for 103 weeks. As matched controls, groups of 50 rats and 50 mice of each sex received tap water. A dose-related depression in mean body weight gain occurred in rats and mice of each sex. Rats and mice given water containing phenol drank less than did the corresponding controls. A dose-related decrease in water consumption was observed for mice. An increased incidence of leukemia or lymphomas was detected in male rats and may have been associated with the administration of phenol. Although the incidence of these tumors in the low-dose group was significantly higher than that in controls, the incidence in the high-dose group was not. Thus an association with administration of phenol was not established. Under the conditions of this bioassay, phenol was not carcinogenic for either male or female F344 rats or male and female B6C3F1 mice. Levels of Evidence of Carcinogenicity: Male Rats: Negative Female Rats: Negative Male Mice: Negative Female Mice: Negative

  14. The carcinogenesis bioassay in perspective: application in identifying human cancer hazards.

    PubMed Central

    Fung, V A; Barrett, J C; Huff, J

    1995-01-01

    The selection process for chemicals tested in the rodent carcinogenicity bioassay has been biased toward chemicals suspected of potential carcinogenicity. Results from carcinogenicity bioassays of 400 chemicals tested by the National Cancer Institute/National Toxicology Program (NCI/NTP) were analyzed to determine the dependence of positive results on chemical selection criteria: those suspected of being carcinogenic and those selected based on large volumes produced and widespread exposures. Of these chemicals, 210 (52%) induced carcinogenicity in at least one organ of one sex of one species of the four sex/species groups typically used by NCI/NTP. Only 92 of the 400 chemicals (23%) were positive in two species and thus by international criteria are considered likely to pose a carcinogenic hazard to humans. A total of 267 chemicals (67%) were selected as suspect carcinogens, and 187 (68%) of these were carcinogenic. Suspect chemicals account for 86% of chemicals with at least one positive result and account for 90% of chemicals considered positive in two species. The International Agency for Research on Cancer (IARC) lists only 5 of the 400 chemicals as carcinogenic to humans (group 1) and 10 as probably carcinogenic to humans (group 2A). The majority (80%) of the 133 chemicals selected only on production/exposure considerations were not carcinogenic in animals, even when tested at the maximum tolerated (or minimally toxic) dose. Only 9 (6.8%) were positive in two species, and none is listed in IARC groups 1 or 2A. Thus, on the basis of our analyses we predict that less than 5-10% of the 75,000 chemicals in commercial use might be reasonably anticipated to be carcinogenic to humans. Images p680-a PMID:7588478

  15. Age-Related Differences in Susceptibility to Carcinogenesis: A Quantitative Analysis of Empirical Animal Bioassay Data

    PubMed Central

    Hattis, Dale; Goble, Robert; Russ, Abel; Chu, Margaret; Ericson, Jen

    2004-01-01

    In revising cancer risk assessment guidelines, the U.S. Environmental Protection Agency (EPA) analyzed animal cancer bioassay data over different periods of life. In this article, we report an improved analysis of these data (supplemented with some chemical carcinogenesis observations not included in the U.S. EPA’s original analysis) and animal bioassay studies of ionizing radiation. We use likelihood methods to avoid excluding cases where no tumors were observed in specific groups. We express dosage for animals of different weights on a metabolically consistent basis (concentration in air or food, or per unit body weight to the three-quarters power). Finally, we use a system of dummy variables to represent exposures during fetal, preweaning, and weaning–60-day postnatal periods, yielding separate estimates of relative sensitivity per day of dosing in these intervals. Central estimate results indicate a 5- to 60-fold increased carcinogenic sensitivity in the birth–weaning period per dose ÷ (body weight0.75-day) for mutagenic carcinogens and a somewhat smaller increase—centered about 5-fold—for radiation carcinogenesis per gray. Effects were greater in males than in females. We found a similar increased sensitivity in the fetal period for direct-acting nitrosoureas, but no such increased fetal sensitivity was detected for carcinogens requiring metabolic activation. For the birth–weaning period, we found an increased sensitivity for direct administration to the pups similar to that found for indirect exposure via lactation. Radiation experiments indicated that carcinogenic sensitivity is not constant through the “adult” period, but the dosage delivered in 12- to 21-month-old animals appears a few-fold less effective than the comparable dosage delivered in young adults (90–105 days of age). PMID:15289159

  16. A new two-phase dimeticone pediculicide shows high efficacy in a comparative bioassay

    PubMed Central

    2009-01-01

    Background Dimeticones kill head lice by physical means. Here we assessed in a comparative bioassay the ex vivo efficacy of "NYDA® sensitiv", a new two-phase dimeticone-based pediculicide similar to a product established on the market, but without fragrances. Methods We compared efficacy of the new product to a positive dimeticone control group, a sample of four other insecticidal and natural head lice products marketed in Germany, and an untreated control. In a bioassay, lice were exposed ex vivo to products and examined for activity for up to 24 hours, following a standard protocol. Results After 6 and 24 hours, 13.7 and 88.5% of untreated control lice did not show major vital signs. In contrast, no lice showed major vital signs 5 minutes after treatment with the new product or the control dimeticone group (NYDA®). This effect persisted at all observation points (100% efficacy). Efficacy of 0.5% permethrin (Infectopedicul®) ranged between 76 and 96% in evaluations between 5 min and 6 hours. All lice treated with a coconut-based compound (mosquito® Läuseshampoo) did not show major vital signs after 5 min, but mortality was only 58% after one hour. Pyrethrum extract (Goldgeist® forte) showed an efficacy of 22 - 52% between 5 min and 3 hours after treatment; after 6 hours, 76% of lice were judged dead. An oxyphthirine®-based compound (Liberalice DUO LP-PRO®) killed 22 - 54% of lice in the first 6 hours. Conclusions The two-phase dimeticone compound NYDA® sensitiv is highly efficacious. The removal of fragrances as compared to an established dimeticone product did not affect in vitro efficacy. PMID:20003435

  17. Effects of sporophyll storage on giant kelp Macrocystis pyrifera (Agardh) bioassay

    SciTech Connect

    Gully, J.R.; Bottomley, J.P.; Baird, R.B.

    1999-07-01

    The giant kelp Macrocystis pyrifera (Agardh) is a US Environmental Protection Agency (US EPA)-approved west coast marine species for chronic toxicity monitoring and compliance in the National Pollution Discharge Elimination System (NPDES). The protocol allows field-collected sporophylls to be stored for up to 24 h at 9 to 12 C prior to use. However, the effects of sporophyll storage on the bioassay results have not been fully investigated, particularly with kelp collected from beds south of Point Conception, CA, USA. Therefore, 13 matched-pair reference toxicant bioassays using fresh and stored sporophylls collected from a subtidal kelp bed near Laguna Beach, CA, USA, were performed and compared. The results indicate that a lower percentage of spores germinate and the germ tube lengths are reduced when stored sporophylls are used. The intratest precision of the germination endpoint decreased as evidenced by significant increases in the percent minimum significant difference (%MSD) statistic. The intertest precision also decreased in the germination endpoint as demonstrated by significant increases in the coefficient of variation (CV) values at four effect levels. Conversely, a significant reduction in the CVs was observed in the germ tube length data, possibly as a consequence of the decrease in germ tube length associated with storage. Finally, significant decreases in mean effect concentrations in the germination endpoint in tests using stored sporophylls indicated that storage increased the sensitivity of the spores to the toxic effects of CuCl{sub 2}. The toxicological sensitivity and intratest precision of the germ tube length endpoint were not significantly affected by storage of the sporophylls. The effects of sporophyll storage resulted in a high frequency of invalid tests, lower statistical power, less effective quality assurance standards, and apparent bias in the observed toxicity of CuCl{sub 2}.

  18. A Miniature Bioassay for Testing the Acute Phytotoxicity of Photosystem II Herbicides on Seagrass

    PubMed Central

    Wilkinson, Adam D.; Collier, Catherine J.; Flores, Florita; Mercurio, Phil; O’Brien, Jake; Ralph, Peter J.; Negri, Andrew P.

    2015-01-01

    Photosystem II (PSII) herbicides have been detected in nearshore tropical waters such as those of the Great Barrier Reef and may add to the pressure posed by runoff containing sediments and nutrients to threatened seagrass habitats. There is a growing number of studies into the potential effects of herbicides on seagrass, generally using large experimental setups with potted plants. Here we describe the successful development of an acute 12-well plate phytotoxicity assay for the PSII herbicide Diuron using isolated Halophila ovalis leaves. Fluorescence images demonstrated Diuron affected the entire leaf surface evenly and responses were not influenced by isolating leaves from the plant. The optimum exposure duration was 24 h, by which time the inhibition of effective quantum yield of PSII (∆F/Fm’) was highest and no deterioration of photosystems was evident in control leaves. The inhibition of ∆F/Fm’ by Diuron in isolated H. ovalis leaves was identical to both potted and hydroponically grown plants (with leaves remaining attached to rhizomes), indicating similar reductions in photosynthetic activity in these acute well-plate assays. The sensitivity of the assay was not influenced by irradiance (range tested 40 to 400 μmol photons m-2 s-1). High irradiance, however, caused photo-oxidative stress in H. ovalis and this generally impacted in an additive or sub-additive way with Diuron to damage PSII. The bioassay using isolated leaves is more rapid, uses far less biological material and does not rely on specialised aquarium facilities in comparison with assays using potted plants. The development and validation of this sensitive bioassay will be useful to reliably screen and monitor the phytotoxicity of existing and emerging PSII herbicides and contribute to risk assessments and water quality guideline development in the future. PMID:25674791

  19. COMPARATIVE ESTROGENICITY OF ESTRADIOL, ETHYNYL ESTRADIOL AND DIETHYLSTILBESTROL IN AN IN VIVO, MALE SHEEPSHEAD MINNOW (CYPRINODON VARIEGATUS), VITELLOGENIN BIOASSAY

    EPA Science Inventory

    An in vivo bioassay for vitellogenin (VTG) synthesis was developed to screen individual chemicals or mixtures of chemicals for potentially estrogenic effects in a marine teleost model. An enzyme-linked immunosorbent assay (ELISA) was used to quantitate VTG synthesis in male sheep...

  20. High through-put aspirator and bioassay system for the evaluation of residual pesticides applied to nat. and artificial substrates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The advancement and testing of residual insecticides on insects is an ongoing mission because of continuous changes in insecticide tolerance. To assay residual insecticides efficiently and rapidly it is necessary for a bioassay to consists of streamlined procedures and equipment specifically intend...

  1. Cleavable DNA-protein hybrid molecular beacon: A novel efficient signal translator for sensitive fluorescence anisotropy bioassay.

    PubMed

    Hu, Pan; Yang, Bin

    2016-01-15

    Due to its unique features such as high sensitivity, homogeneous format, and independence on fluorescent intensity, fluorescence anisotropy (FA) assay has become a hotspot of study in oligonucleotide-based bioassays. However, until now most FA probes require carefully customized structure designs, and thus are neither generalizable for different sensing systems nor effective to obtain sufficient signal response. To address this issue, a cleavable DNA-protein hybrid molecular beacon was successfully engineered for signal amplified FA bioassay, via combining the unique stable structure of molecular beacon and the large molecular mass of streptavidin. Compared with single DNA strand probe or conventional molecular beacon, the DNA-protein hybrid molecular beacon exhibited a much higher FA value, which was potential to obtain high signal-background ratio in sensing process. As proof-of-principle, this novel DNA-protein hybrid molecular beacon was further applied for FA bioassay using DNAzyme-Pb(2+) as a model sensing system. This FA assay approach could selectively detect as low as 0.5nM Pb(2+) in buffer solution, and also be successful for real samples analysis with good recovery values. Compatible with most of oligonucleotide probes' designs and enzyme-based signal amplification strategies, the molecular beacon can serve as a novel signal translator to expand the application prospect of FA technology in various bioassays.

  2. Using macroalgal δ15N bioassay to detect cruise ship waste water effluent inputs in Skagway, AK

    EPA Science Inventory

    Nitrogen stable isotopes are a powerful tool for tracking sources of N to marine ecosystems. I used green macroalgae as a bioassay organism to evaluate if the δ15N signature of cruise ship waste water effluent (CSWWE) could be detected in Skagway Harbor, AK. Opportunistic green...

  3. Cumulative toxicity of an environmentally relevant mixture of nine regulated disinfection by-products in a multigenerational rat reproductive bioassay

    EPA Science Inventory

    CUMULATIVE TOXICITY OF AN ENVIRONMENTALLY RELEVANT MIXTURE OF NINE REGULATED DISINFECTION BY-PRODUCTS IN A MULTIGENERATIONAL RAT REPRODUCTIVE BIOASSAY J E Simmons, GR. Klinefelter, JM Goldman, AB DeAngelo, DS Best, A McDonald, LF Strader, AS Murr, JD Suarez, MH George, ES Hunte...

  4. Comparison evaluation of liquid chromatographic and bioassay methods of analysis for determination of paralytic shellfish poisons in shellfish tissues.

    PubMed

    Salter, J E; Timperi, R J; Hennigan, L J; Sefton, L; Reece, H

    1989-01-01

    A liquid chromatographic (LC) method was compared with the AOAC mouse bioassay method (18.086-18.092) for determination of paralytic shellfish toxins in shellfish tissues. Shellfish samples were collected from Massachusetts coastal waters as part of a state surveillance program, and extracts of shellfish meat were analyzed for toxins by using both analytical methods. Overall correlation of the LC and bioassay methods is good (r = 0.943), but for samples with toxicities less than 100 micrograms saxitoxin/100 g shellfish meat, the correlation is significantly less (r = 0.531). Limits of detection are 10 micrograms saxitoxin/100 g shellfish meat and 40 micrograms saxitoxin/100 g shellfish meat for the LC and bioassay methods, respectively. Analytical capacity of the LC method is limited to 12 samples/person-day compared with 30 samples/person-day for the bioassay. Sampling capacity of the LC method could be increased by using a fluorescence detector with a wider response range, which would eliminate the need for dilution of concentrated samples.

  5. Studies of the Stimulus Specificity, Response Specificity, Process Specificity, and Task Specificity of the Behavioral Bioassay Phenomenon. Final Report.

    ERIC Educational Resources Information Center

    Braud, William G.

    If biochemical substrates and mechanisms could be identified, progress might be made in the detection and remediation of certain learning and memory disabilities. "Memory transfer" or "behavioral bioassay" methodology is a new technique developed for this purpose. It uses the behavior recipient animals to detect whatever chemicals are synthesized…

  6. Identification of Androgen Receptor Antagonists in Fish Using a Simple Bioassay with the Fathead Minnow Pimephales promelas .

    EPA Science Inventory

    Considerable effort has been expended on the development of bioassays to detect chemicals that affect endocrine function controlled by the vertebrate hypothalamic-pituitary-gonadal (HPG) axis via different mechanisms/modes of action (MOA). Antagonism of the androgen receptor (AR)...

  7. Syringe test (modified larval immersion test): a new bioassay for testing acaricidal activity of plant extracts against Rhipicephalus microplus.

    PubMed

    Sindhu, Zia-ud-Din; Jonsson, Nicholas N; Iqbal, Zafar

    2012-09-10

    We report a new bioassay "syringe test" (modified larval immersion test) for in vitro evaluation of acaricidal activity of crude plant extracts. Prepared syringes, containing eggs of tick, were incubated until 14 d after hatching of eggs, when the bioassay was performed on the larvae. Lethal concentrations for 50% of larvae (LC(50)), LC(90) and LC(99) values were calculated for each tested product. 95% confidence intervals for LC(50) were very narrow, indicating a high degree of repeatability for the new bioassay on larvae of R. microplus. Bioassays were applied to six crude aqueous-methanol extracts from five plants (Acacia nilotica, Buxus papillosa, Fumaria parviflora, Juniperus excelsa, and Operculina turpethum), of which three showed discernible effects. Twenty-four hours post exposure, LC(99) values were 11.9% (w/v) for F. parviflora, 20.8% (w/v) and 29.2% (w/v) for B. papillosa and A. nilotica, respectively. After six days of exposure these values were; 9.1% (w/v), 9.2% (w/v) and 15.5 (w/v) for F. parviflora, A. nilotica and B. papillosa, respectively.

  8. USE OF BIOASSAY-DIRECTED CHEMICAL ANALYSIS FOR IDENTIFYING MUTAGENIC COMPOUNDS IN URBAN AIR AND COMBUSTION EMISSIONS

    EPA Science Inventory

    Bioassay-directed chemical analysis fractionation has been used for 30 years to identify mutagenic classes of compounds in complex mixtures. Most studies have used the Salmonella (Ames) mutagenicity assay, and we have recently applied this methodology to two standard reference sa...

  9. USE OF PLANT AND EARTHWORM BIOASSAYS TO EVALUATE REMEDIATION OF SOIL FROM A SITE CONTAMINATED WITH POLYCHLORINATED BIPHENYLS

    EPA Science Inventory

    Soil from a site heavily contaminated with polychlorinated biphenyls (PCBs) was treated with a pilot-scale, solvent extraction technology. Bioassays in earthworms and plants were used to examine the efficacy of the remediation process for reducing the toxicity of the soil. The ...

  10. A chlorophyll a fluorescence-based Lemna minor bioassay to monitor microbial degradation of nanomolar to micromolar concentrations of linuron.

    PubMed

    Hulsen, Kris; Minne, Veerle; Lootens, Peter; Vandecasteele, Paul; Höfte, Monica

    2002-06-01

    A plant-microbial bioassay, based on the aquatic macrophyte Lemna minor L. (duckweed), was used to monitor biodegradation of nano- and micromolar concentrations of the phenylurea herbicide linuron. After 7 days of exposure to linuron, log-logistic-based dose-response analysis revealed significant growth inhibition on the total frond area of L. minor when linuron concentrations > or = 80 nM were added to the bioassay. A plant-protective effect was obtained for all concentrations > 80 nM by inoculation with either a bacterial consortium or Variovorax paradoxus WDL1, which is probably the main actor in this consortium. The outcome of the plant-microbe-toxicant interaction was also assessed using pulse amplitude-modulated chlorophyll a fluorescence and chlorophyll a fluorescence imaging. Linuron toxicity to L. minor became apparent as a significant decrease in the effective quantum yield (Delta F/Fm') within 90 min after exposure of the plants to linuron concentrations > or = 160 nM. Inoculation of the bioassay with the linuron-degrading bacteria neutralized the effect on the effective quantum yield at concentrations > or = 160 nM, indicating microbial degradation of these concentrations. The chlorophyll a fluorescence-based Lemna bioassay described here offers a sensitive, fast and cost-effective approach to study the potential of biodegrading microorganisms to break down minute concentrations of photosynthesis-inhibiting xenobiotics.

  11. Fish bioassay and toxin induction experiments for research on Pfiesteria piscicida and other toxic dinoflagellates: workshop summary.

    PubMed

    Rogers, H S; Backer, L

    2001-10-01

    In late January 2000, the Centers for Disease Control and Prevention sponsored a workshop to discuss standardizing the laboratory materials and methods used for in vivo fish bioassays and toxin induction experiments. Representatives from six laboratories using these assays to conduct research on Pfiesteria piscicida Steidinger & Burkholder, similar organisms (i.e., members of the toxic Pfiesteria complex) or their toxins were invited to attend. The workshop objectives were a) to discuss the need for uniform quality assurance for fish bioassays and toxin induction, b) to encourage publishing the relevant materials and methods in the literature, c) to foster communication among the laboratories conducting this work, and d) to respond to requests from state health and environmental protection agencies for guidance in interpreting the results from fish bioassays conducted in different laboratories. To facilitate discussion at the workshop, researchers conducting Pfiesteria research completed a detailed questionnaire in advance about fish bioassays and toxin production assays. Workshop participants discussed experimental factors that might influence the reproducibility or interpretation of fish bioassays and toxin-induction experiments. The experimental factors were categorized into physical, chemical, and biological parameters. In addition, participants ranked experimental factors by their relative importance in conducting these assays as a) factors that are critically important and should be maintained within a recommended range, b) factors that are important in conducting the assays but that may be variable among laboratories or within experiments and whose values should be recorded and reported by investigators, and c) factors of unknown importance that should be considered important research questions. This article summarizes results obtained from the questionnaire and workshop discussions.

  12. Investigation of independence in inter-animal tumor-type occurrences within the NTP rodent-bioassay database

    SciTech Connect

    Bogen, K.T.; Seilkop, S.

    1993-05-01

    Statistically significant elevation in tumor incidence at multiple histologically distinct sites is occasionally observed among rodent bioassays of chemically induced carcinogenesis. If such data are to be relied on (as they have, e.g., by the US EPA) for quantitative cancer potency assessment, their proper analysis requires a knowledge of the extent to which multiple tumor-type occurrences are independent or uncorrelated within individual bioassay animals. Although difficult to assess in a statistically rigorous fashion, a few significant associations among tumor-type occurrences in rodent bioassays have been reported. However, no comprehensive studies of animal-specific tumor-type occurrences at death or sacrifice have been conducted using the extensive set of available NTP rodent-bioassay data, on which most cancer-potency assessment for environmental chemicals is currently based. This report presents the results of such an analysis conducted on behalf of the National Research Council`s Committee on Risk Assessment for Hazardous Air Pollutants. Tumor-type associations among individual animals were examined for {approximately}2500 to 3000 control and {approximately}200 to 600 treated animals using pathology data from 62 B6C3F1 mouse studies and 61 F/344N rat studies obtained from a readily available subset of the NTP carcinogenesis bioassay database. No evidence was found for any large correlation in either the onset probability or the prevalence-at-death or sacrifice of any tumor-type pair investigated in control and treated rats and niece, although a few of the small correlations present were statistically significant. Tumor-type occurrences were in most cases nearly independent, and departures from independence, where they did occur, were small. This finding is qualified in that tumor-type onset correlations were measured only indirectly, given the limited nature of the data analyzed.

  13. Deltamethrin resistance in the sea louse Caligus rogercresseyi (Boxhall and Bravo) in Chile: bioassay results and usage data for antiparasitic agents with references to Norwegian conditions.

    PubMed

    Helgesen, K O; Bravo, S; Sevatdal, S; Mendoza, J; Horsberg, T E

    2014-10-01

    The sea louse Caligus rogercresseyi is a major threat to Chilean salmonid farming. Pyrethroids have been used for anticaligus treatments since 2007, but have shown reduced effect, most likely due to resistance development. Pyrethroid resistance is also a known problem in Lepeophtheirus salmonis in the Northern Hemisphere. This study describes the development of deltamethrin resistance in C. rogercresseyi based on bioassays and usage data for pyrethroids in Chilean aquaculture. These results were compared to bioassays from L. salmonis from Norway and to Norwegian usage data. Available deltamethrin bioassay results from 2007 and 2008, as well as bioassays from Norway, were collected and remodelled. Bioassays were performed on field-collected sea lice in region X in Chile in 2012 and 2013. Bioassays from 2007 were performed prior to the introduction of pyrethroids to the Chilean market. Both the results from 2008 and 2012 showed an increased resistance. Increased pyrethroid resistance was also indicated by the increased use of pyrethroids in Chilean aquaculture compared with the production of salmonids. A similar trend was seen in the Norwegian usage data. The bioassay results from Chile from 2012 and 2013 also indicated a difference in the susceptibility to deltamethrin between male and female caligus.

  14. Low-Level Plutonium Bioassay Measurements at the Lawrence Livermore National Laboratory

    SciTech Connect

    Hamilton, T; Brown, T; Hickman, D; Marchetti, A; Williams, R; Kehl, S

    2007-06-18

    Plutonium-239 ({sup 239}Pu) and plutonium-240 ({sup 240}Pu) are important alpha emitting radionuclides contained in radioactive debris from nuclear weapons testing. {sup 239}Pu and {sup 240}Pu are long-lived radionuclides with half-lives of 24,400 years and 6580 years, respectively. Concerns over human exposure to plutonium stem from knowledge about the persistence of plutonium isotopes in the environment and the high relative effectiveness of alpha-radiation to cause potential harm to cells once incorporated into the human body. In vitro bioassay tests have been developed to assess uptakes of plutonium based on measured urinary excretion patterns and modeled metabolic behaviors of the absorbed radionuclides. Systemic plutonium absorbed by the deep lung or from the gastrointestinal tract after ingestion is either excreted or distributed to other organs, primarily to the liver and skeleton, where it is retained for biological half-times of around 20 and 50 years, respectively. Dose assessment and atoll rehabilitation programs in the Marshall Islands have historically given special consideration to residual concentrations of plutonium in the environment even though the predicted dose from inhalation and/or ingestion of plutonium accounts for less than 5% of the annual effective dose from exposure to fallout contamination. Scientists from the Lawrence Livermore National Laboratory (LLNL) have developed a state-of-the-art bioassay test to assess urinary excretion rates of plutonium from Marshallese populations. This new heavy-isotope measurement system is based on Accelerator Mass Spectrometry (AMS). The AMS system at LLNL far exceeds the standard measurement requirements established under the latest United States Department of Energy (DOE) regulation, 10CFR 835, for occupational monitoring of plutonium, and offers several advantages over classical as well as competing new technologies for low-level detection and measurement of plutonium isotopes. The United States

  15. Effect-based trigger values for in vitro bioassays: Reading across from existing water quality guideline values.

    PubMed

    Escher, Beate I; Neale, Peta A; Leusch, Frederic D L

    2015-09-15

    Cell-based bioassays are becoming increasingly popular in water quality assessment. The new generations of reporter-gene assays are very sensitive and effects are often detected in very clean water types such as drinking water and recycled water. For monitoring applications it is therefore imperative to derive trigger values that differentiate between acceptable and unacceptable effect levels. In this proof-of-concept paper, we propose a statistical method to read directly across from chemical guideline values to trigger values without the need to perform in vitro to in vivo extrapolations. The derivation is based on matching effect concentrations with existing chemical guideline values and filtering out appropriate chemicals that are responsive in the given bioassays at concentrations in the range of the guideline values. To account for the mixture effects of many chemicals acting together in a complex water sample, we propose bioanalytical equivalents that integrate the effects of groups of chemicals with the same mode of action that act in a concentration-additive manner. Statistical distribution methods are proposed to derive a specific effect-based trigger bioanalytical equivalent concentration (EBT-BEQ) for each bioassay of environmental interest that targets receptor-mediated toxicity. Even bioassays that are indicative of the same mode of action have slightly different numeric trigger values due to differences in their inherent sensitivity. The algorithm was applied to 18 cell-based bioassays and 11 provisional effect-based trigger bioanalytical equivalents were derived as an illustrative example using the 349 chemical guideline values protective for human health of the Australian Guidelines for Water Recycling. We illustrate the applicability using the example of a diverse set of water samples including recycled water. Most recycled water samples were compliant with the proposed triggers while wastewater effluent would not have been compliant with a few

  16. The release of a non-prostanoid inhibitory factor from rabbit bronchus detected by co-axial bioassay.

    PubMed

    Spina, D; Page, C P

    1991-04-01

    1. Methacholine relaxed phenylephrine-contracted aorta of the rat with the endothelium intact. This effect was inhibited by haemoglobin, methylene blue, gossypol, phenidone and L-NG-nitroarginine methyl ester (L-NAME). Rat aorta denuded of endothelium failed to relax in response to methacholine, histamine and the peptidoleukotrienes C4, D4 and E4. 2. Methacholine and histamine but not leukotrienes C4, D4 and E4 relaxed phenylephrine-contracted rat aorta without endothelium when surrounded by rabbit epithelium-intact bronchus. The muscarinic antagonist atropine antagonized the methacholine-induced relaxation. 3. Removal of the epithelium either mechanically or chemically, abolished methacholine-induced relaxation of rat aorta in the co-axial bioassay. These data indicate that the epithelium is responsible for the observed relaxant effect to methacholine and histamine. 4. The cyclo-oxygenase inhibitor, indomethacin, the phospholipase A2 inhibitor, mepacrine and the lipoxygenase inhibitor, nordihydroguaiaretic acid (NDGA), failed to inhibit methacholine-induced relaxation of rat aorta in the co-axial bioassay. This indicates that the epithelium-derived inhibitory factor (EpDIF) is not a product of the cyclo-oxygenase or lipoxygenase pathway or a product derived from activation of phospholipase A2. 5. Haemoglobin, methylene blue, phenidone, gossypol and L-NAME failed to inhibit the relaxation of rat aorta in the co-axial bioassay. These results demonstrate that EpDIF detected in the co-axial bioassay is not endothelium-derived relaxing factor (EDRF) or nitric oxide. Similarly, catalase was without effect. 6. EpDIF is unlikely to be a peptide since papain and alpha-chymotrypsin failed to alter the methacholine-induced relaxation of rat aorta in the co-axial bioassay. Furthermore, thiorphan, captopril and aprotinin were also without effect, suggesting that EpDIF is not a substrate for airway peptidases. 7. The results presented in this paper demonstrate the release of a

  17. Assessment of mobility and bioavailability of contaminants in MSW incineration ash with aquatic and terrestrial bioassays.

    PubMed

    Ribé, V; Nehrenheim, E; Odlare, M

    2014-10-01

    Incineration of municipal solid waste (MSW) is a waste treatment method which can be sustainable in terms of waste volume reduction as well as a source of renewable energy. In the process fly and bottom ash is generated as a waste material. The ash residue may vary greatly in composition depending on the type of waste incinerated and it can contain elevated levels of harmful contaminants such as heavy metals. In this study, the ecotoxicity of a weathered, untreated incineration bottom ash was characterized as defined by the H14 criterion of the EU Waste Framework Directive by means of an elemental analysis, leaching tests followed by a chemical analysis and a combination of aquatic and solid-phase bioassays. The experiments were conducted to assess the mobility and bioavailability of ash contaminants. A combination of aquatic and terrestrial bioassays was used to determine potentially adverse acute effects of exposure to the solid ash and aqueous ash leachates. The results from the study showed that the bottom ash from a municipal waste incineration plant in mid-Sweden contained levels of metals such as Cu, Pb and Zn, which exceeded the Swedish EPA limit values for inert wastes. The chemical analysis of the ash leachates showed high concentrations of particularly Cr. The leachate concentration of Cr exceeded the limit value for L/S 10 leaching for inert wastes. Filtration of leachates prior to analysis may have underestimated the leachability of complex-forming metals such as Cu and Pb. The germination test of solid ash and ash leachates using T. repens showed a higher inhibition of seedling emergence of seeds exposed to the solid ash than the seeds exposed to ash leachates. This indicated a relatively low mobility of toxicants from the solid ash into the leachates, although some metals exceeded the L/S 10 leaching limit values for inert wastes. The Microtox® toxicity test showed only a very low toxic response to the ash leachate exposure, while the D. magna

  18. Synthesis, Characterization, and Application of Metal-Chelating Polymers for Mass Cytometric Bioassays

    NASA Astrophysics Data System (ADS)

    Majonis, Daniel

    This thesis describes the synthesis, characterization, and application of metal-chelating polymers for mass-cytometric bioassays. Mass cytometry is a cell characterization technique in which cells are injected individually into an ICP-MS detector. Signal is provided by staining cell-surface or intracellular antigens with metal-labeled antibodies (Abs). These Abs are labeled through the covalent attachment of metal-chelating polymers which carry multiple copies of a lanthanide isotope. In this work, my first goal was to develop a facile, straightforward synthesis of a new generation of metal-chelating polymers. The synthesis began with reversible addition-fragmentation chain transfer polymerization, and was followed by numerous post-polymerization pendant group transformations to introduce DTPA lanthanide chelators to every repeat unit, and a maleimide at the end of the chain. The second goal was to apply these metal-chelating polymers in bioassay experiments. The DTPA groups were loaded with lanthanide ions, and the maleimide group was used to covalently attach the polymer to an Ab. This goat anti-mouse conjugate was found to carry an average of 2.4 +/- 0.3 polymer chains. Then, primary Ab conjugates were prepared and used in an 11-plex mass cytometry assay in the characterization of umbilical cord blood cells. The third goal was to expand the multiplexity of the assay. In current technology, the number of Abs that can be monitored simultaneously is limited to the 31 commercially available, stable lanthanide isotopes. Thus, I had an interest in preparing metal-chelating polymers that could carry other metals in the 100-220 amu range. I synthesized polymers with four different polyaminocarboxylate ligands, and investigated the loading of palladium and platinum ions into these polymers. Polymer-Ab conjugates prepared with palladium- and platinum-loaded polymers gave curious results, in that only dead cells were recognized. The fourth goal was to create dual

  19. Determination of an Environmental Background Level of Sr-90 in Urine for the Hanford Bioassay Program Determination of an Environmental Background Level of Sr-90 in Urine for the Hanford Bioassay Program

    SciTech Connect

    Antonio, Cheryl L.; Rivard, James W.

    2009-11-01

    During the decommissioning and maintenance of some of the facilities at the U.S. Department of Energy Hanford Site in Washington State, workers have potential for a 90Sr intake. However, because of worldwide radioactive fallout, 90Sr is present in our environment, and can be detectable in routine urine bioassay samples. It is important for the Hanford Site bioassay program to discern an occupational intake from a non-occupational environmental one. A detailed study of the background 90Sr in the urine of unexposed Hanford workers was performed. A survey of the Hanford Site bioassay database found 128 Hanford workers who were hired between 1997 and 2002 and who had a very low potential for an occupational exposure prior to the baseline strontium urinalysis. Each urinalysis sample represented excretion during an approximate 24-hr period. The arithmetic mean value for the 128 pre-exposure baselines was 3.6 ± 5.1 mBq d-1. The 90Sr activities in urine varied from -12 to 20 mBq. The 99th percentile result was 16.4 mBqd-1, which was interpreted to mean that 1% of Hanford workers not occupationally exposed to strontium might exceed 16.4 mBq d-1.

  20. Molecular Engineering of Thiazole Orange Dye: Change of Fluorescent Signaling from Universal to Specific upon Binding with Nucleic Acids in Bioassay.

    PubMed

    Lu, Yu-Jing; Deng, Qiang; Hou, Jin-Qiang; Hu, Dong-Ping; Wang, Zheng-Ya; Zhang, Kun; Luyt, Leonard G; Wong, Wing-Leung; Chow, Cheuk-Fai

    2016-04-15

    The universal fluorescent staining property of thiazole orange (TO) dye was adapted in order to be specific for G-quadruplex DNA structures, through the introduction of a styrene-like substituent at the ortho-position of the TO scaffold. This extraordinary outcome was determined from experimental studies and further explored through molecular docking studies. The molecular docking studies help understand how such a small substituent leads to remarkable fluorescent signal discrimination between G-quadruplex DNA and other types of nucleic acids. The results reveal that the modified dyes bind to the G-quadruplex or duplex DNA in a similar fashion as TO, but exhibit either enhanced or quenched fluorescent signal, which is determined by the spatial length and orientation of the substituent and has never been known. The new fluorescent dye modified with a p-(dimethylamino)styryl substituent offers 10-fold more selectivity toward telomeric G-quadruplexes than double-stranded DNA substrates. In addition, native PAGE experiments, FRET, CD analysis, and live cell imaging were also studied and demonstrated the potential applications of this class of thiazole-orange-based fluorescent probes in bioassays and cell imaging.

  1. Acute toxicity bioassay of dimethoate on freshwater airbreathing catfish, Heteropneustes fossilis (Bloch).

    PubMed

    Pandey, Rakesh K; Singh, Ram N; Singh, Sarika; Singh, Narendra N; Das, Vijai K

    2009-05-01

    Pesticides are chemicals used for pest control in the agricultural fields. They finally reach the surrounding water bodies through surface runoff affecting the aquatic fauna. Dimethoate is frequently used organophosphate pesticide due to its high effectiveness and rapid breakdown into environmentally safe products. A 96 hr static acute toxicity test was carried out to determine the LC50 value of dimethoate, on the freshwater airbreathing catfish Heteropneustes fossilis (Bloch). The fish were exposed to 7 different concentrations of dimethoate (2.50, 2.75, 3.00, 3.25, 3.50, 3.75 and 4.00 mg l(-1)) for toxicity bioassay. Control (0.00 mg l(-1)) was also carried out. The data were subjected to Finney's Probit analysis and processed with Trimmed Spearman-Karber statistical software. The LC50 values for dimethoate for 24, 48, 72 and 96 hr were 3.38, 3.23, 3.08 and 2.98 mg l(-1), respectively. At higher concentration of dimethoate (3.25 mg l(-1) and above) the fish showed uncoordinated behaviour such as erratic and jerky swimming, attempt to jump out of water, frequent surfacing and gulping of air, decrease in opercular movement and copious secretion of mucus all over the body.

  2. Environmental effects of dredging: Wetland animal bioassay of saltwater dredged material

    SciTech Connect

    1986-01-01

    The Clean Water Act requires that the environmental evaluation of dredged material prior to discharge or impacting the waters of the United States include the effects of disposal on contaminant concentrations through biological processes. This resulted in a need for Corps of Engineers Districts to be able to predict the potential contamination of animals that may be associated with each of these potential disposal alternatives: open-water disposal, upland disposal, and/or wetland creation. The following is a summary of a wetland animal solid-phase bioassay test applied to sediment collected from the waterway at Black Rock Harbor (BRH), Bridgeport, Connecticut. This test procedure was designed to evaluate the potential movement of toxic heavy metals and other contaminants from dredged material placed in a wetland (reduced) environment into sediment-dwelling intertidal invertebrates as a first step that may be used to evaluate contaminant mobility to animals that may colonize the dredged material. No inference on the movement of contaminants through the wetland food web is offered at this time.

  3. Evaluation of coriander spice as a functional food by using in vitro bioassays.

    PubMed

    Zhang, Chuan-Rui; Dissanayake, Amila A; Kevseroğlu, Kudret; Nair, Muraleedharan G

    2015-01-15

    Coriander leaves and seeds are widely used as a condiment and spice. The use of roasted coriander seeds in food and beverage is very common. In this study, we investigated raw and roasted coriander seeds for their functional food quality using antioxidant, anti-inflammatory and human tumour cell proliferation inhibitory assays. The hexane and methanolic extracts of raw and roasted coriander seeds showed identical chromatographic and bioassay profiles. Chromatographic purification of the roasted seed extracts afforded tripetroselinin as the predominant component. Other isolates were petroselinic acid, 1,3-dipetroselinin, 2-C-methyl-d-erythritol, 2-C-methyl-d-erythritol 4-O-β-d-glucopyranoside and linalool. Hexane and methanolic extracts of both raw and roasted seeds and pure isolates from them showed comparable antioxidant and anti-inflammatory activities to the positive controls used in the assays, and inhibited the growth of human tumour cells AGS (gastric carcinoma), DU-145 and LNCaP (prostate carcinoma), HCT-116 (colon carcinoma), MCF-7 (breast carcinoma) and NCI-H460 (lung carcinoma) by 4-34%, respectively.

  4. Bioassay-guided isolation and identification of cytotoxic compounds from Gymnosperma glutinosum leaves.

    PubMed

    Quintanilla-Licea, Ramiro; Morado-Castillo, Rolando; Gomez-Flores, Ricardo; Laatsch, Hartmut; Verde-Star, María Julia; Hernández-Martínez, Humberto; Tamez-Guerra, Patricia; Tamez-Guerra, Reyes; Rodríguez-Padilla, Cristina

    2012-09-20

    Bioassay-guided fractionation of hexane extracts of Gymnosperma glutinosum (Asteraceae) leaves, collected in North Mexico, afforded the known compounds hentriacontane (1) and (+)-13S,14R,15-trihydroxy-ent-labd-7-ene (2), as well as the new ent-labdane diterpene (-)-13S,14R,15-trihydroxy-7-oxo-ent-labd-8(9)-ene (3). In addition, D-glycero-D-galactoheptitol (4) was isolated from the methanolic extract of this plant. Their structures were established on the basis of high-field 1D- and 2D NMR methods supported by HR-MS data. The cytotoxic activity was determined by using the in vitro L5178Y-R lymphoma murine model. Hentriacontane (1) and the new ent-labdane 3 showed weak cytotoxicity, whereas the ent-labdane 2 showed significant (p < 0.05) and concentration dependent cytotoxicity (up to 78%) against L5178Y-R cells at concentrations ranging from 7.8 to 250 μg/mL.

  5. Assessment of coastal pollution through bioassay and transplantation of intertidal clams.

    PubMed

    Jaiswar, A K; Kulkarni, B G; Chakraborty, S K

    2006-04-01

    In the present study, a survey of Mahim creek and Bay area was undertaken that indicated absence of fauna, particularly molluscs from the area, which was a repository in the past. During bioassay experiments of Mahim creek water, the clams G. divaricatum and C. antiquata could not open their valves in 100% creek water and died within 12 hrs of exposure. The 96 hrs LC50 values of Mahim creek water for G. divaricatum and C. antiquata were found to be 20% and 40% respectively during summer and 38% and 57% respectively during rainy season. When two sets of the clams were transplanted at Mahim creek, they died within 12 hrs. These experiments suggest the extreme level of pollution in the area. This level of pollution is responsible for transforming the area into barren locality in terms of fauna, specially the rich molluscan diversity. However, Gorai creek was found to be comparatively very less polluted and it still serves as breeding and nursery ground for various fishes and prawn species. Hence it must be protected and conserved.

  6. Multiple linear and principal component regressions for modelling ecotoxicity bioassay response.

    PubMed

    Gomes, Ana I; Pires, José C M; Figueiredo, Sónia A; Boaventura, Rui A R

    2014-01-01

    The ecotoxicological response of the living organisms in an aquatic system depends on the physical, chemical and bacteriological variables, as well as the interactions between them. An important challenge to scientists is to understand the interaction and behaviour of factors involved in a multidimensional process such as the ecotoxicological response. With this aim, multiple linear regression (MLR) and principal component regression were applied to the ecotoxicity bioassay response of Chlorella vulgaris and Vibrio fischeri in water collected at seven sites of Leça river during five monitoring campaigns (February, May, June, August and September of 2006). The river water characterization included the analysis of 22 physicochemical and 3 microbiological parameters. The model that best fitted the data was MLR, which shows: (i) a negative correlation with dissolved organic carbon, zinc and manganese, and a positive one with turbidity and arsenic, regarding C. vulgaris toxic response; (ii) a negative correlation with conductivity and turbidity and a positive one with phosphorus, hardness, iron, mercury, arsenic and faecal coliforms, concerning V. fischeri toxic response. This integrated assessment may allow the evaluation of the effect of future pollution abatement measures over the water quality of Leça River.

  7. Detection of genotoxic effects of drinking water disinfection by-products using Vicia faba bioassay.

    PubMed

    Hu, Yu; Tan, Li; Zhang, Shao-Hui; Zuo, Yu-Ting; Han, Xue; Liu, Na; Lu, Wen-Qing; Liu, Ai-Lin

    2017-01-01

    Plant-based bioassays have gained wide use among the toxicological and/or ecotoxicological assessment procedures because of their simplicity, sensitivity, low cost, and reliability. The present study describes the use of Vicia faba (V. faba) micronucleus (MN) test and V. faba comet assay in the evaluation of the genotoxic potential of disinfection by-products (DBPs) commonly found in chlorine-disinfected drinking water. Five haloacetic acids and three halogenated acetonitriles were chosen as representatives of DBPs in this study because they are of potentially great public health risk. Results of the MN test indicated that monochloroacetic acid (MCA), monobromoacetic acid (MBA), dichloroacetic acid (DCA), dibromoacetic acid (DBA), trichloroacetic acid (TCA), and trichloroacetonitrile (TCAN) caused a statistically significant increase in MN frequency in V. faba root tip cells. However, no genotoxic response was observed for dichloroacetonitrile (DCAN) and dibromoacetonitrile (DBAN). Results of the comet assay showed that all tested DBPs induced a statistically significant increase in genomic DNA damage to V. faba root tip cells. On considering the capacity to detect genomic damage of a different nature, we suggest that a combination of V. faba MN test and V. faba comet assay is a useful tool for the detection of genotoxic effects of DBPs. It is worthy of assessing the feasibility of using V. faba comet assay combined with V. faba MN test to screen for the genotoxic activity of chlorinated drinking water in future work.

  8. Results of an in-situ mussel bioassay in the Puget Sound

    SciTech Connect

    Houkal, D.; Rummel, B.; Shephard, B.

    1995-12-31

    As part of an ecological evaluation in the Puget Sound, Washington, an in situ bioassay using the blue mussel (Mytilus galloprovincialis) was conducted to determine the effect of sediment-borne chemicals on bioaccumulation and growth of shellfish. The assay included four sample stations from a contaminated embayment (Sinclair Inlet) and one station from a reference site (Holmes Harbor). At each station, 300 mussels were deployed 1 meter above the sediment surface and maintained for a period of 3 months. The length and total weight of each mussel was measured at the beginning of the exposure period and the length, total weight, tissue weight, and shell weight of each mussel was measured at the end of the exposure period. Composite tissue samples from 100 mussels were collected at the beginning and end of the exposure period and analyzed for semivolatile organic chemicals, chlorinated pesticides, polychlorinated biphenyls, inorganic chemicals, organotin, and lipids. Water quality measurements (including temperature, salinity, dissolved oxygen, and chlorophyll a) were made at each station every two weeks during the assay to characterize environmental factors influencing mussel bioaccumulation and growth. Weight growth was similar among stations in Sinclair Inlet, but was significantly greater in all Sinclair Inlet stations compared to the Holmes Harbor reference station. Length growth was statistically indistinguishable among stations in Sinclair Inlet. Only one Sinclair Inlet station had a significantly greater length growth compared to the Holmes Harbor reference station. The influence of water quality on mussel growth is presented. The correlation between sediment chemistry and bioaccumulation is discussed.

  9. A novel high-throughput irradiator for in vitro radiation sensitivity bioassays

    NASA Astrophysics Data System (ADS)

    Fowler, Tyler L.

    Given the emphasis on more personalized radiation therapy there is an ongoing and compelling need to develop high-throughput screening tools to further examine the biological effects of ionizing radiation on cells, tissues and organ systems in either the research or clinical setting. Conventional x-ray irradiators are designed to provide maximum versatility to radiobiology researchers, typically accommodating small animals, tissue or blood samples, and cellular applications. This added versatility often impedes the overall sensitivity and specificity of an experiment resulting in a trade-off between the number of absorbed doses (or dose rates) and biological endpoints that can be investigated in vitro in a reasonable amount of time. Therefore, modern irradiator designs are incompatible with current high-throughput bioassay technologies. Furthermore, important dosimetry and calibration characteristics (i.e. dose build-up region, beam attenuation, and beam scatter) of these irradiators are typically unknown to the end user, which can lead to significant deviation between delivered dose and intended dose to cells that adversely impact experimental results. Therefore, the overarching goal of this research is to design and develop a robust and fully automated high-throughput irradiator for in vitro radiation sensitivity investigations. Additionally, in vitro biological validation of this system was performed by assessing intracellular reactive oxygen species production, physical DNA double strand breaks, and activation of cellular DNA repair mechanisms. Finally, the high-throughput irradiator was used to investigate autophagic flux, a cellular adaptive response, as a potential biomarker of radiation sensitivity.

  10. Towards the development of an embryotoxicity bioassay with terrestrial snails: screening approach for cadmium and pesticides.

    PubMed

    Druart, Coline; Scheifler, Renaud; de Vaufleury, Annette

    2010-12-15

    Currently no bioassays are available to assess the embryotoxicity of chemicals with terrestrial soil invertebrates. We therefore presented a new method for embryotoxicity testing with snail eggs: a relevant biological material that incubates in soil and that can be exposed to contaminants from leachates and soil solution. The effects of aqueous solutions of two herbicide formulations, Reglone(®) (active ingredient (a.i.), diquat) and Roundup(®) or its a.i., glyphosate, of a surfactant (Agral(®) 90, a.i., nonylphenol polyethoxylates) and of cadmium (Cd) were studied. Endpoints were the hatching success and observations of embryo abnormalities after exposure. Roundup(®) was found to be more toxic than its a.i. alone (EC50(a.i.)=18 mg/l and about 1300 mg/l, respectively). Reglone(®) (EC50(a.i.)=0.72 mg/l) and Agral(®) (EC50(a.i.) ≈ 50 mg/l) were also tested together, revealing that Reglone(®) accounted for more than 99% of the mixture's toxicity. An antagonistic interaction between the two substances was found. For Cd (EC50=3.9 mg/l), a significant transfer from exposure medium to eggs was emphasized, particularly affecting the albumen. Abnormalities of embryogenesis in non-hatched embryos depended on the substance and the concentration considered.

  11. Comparative study on toxicity evaluation of anaerobically treated parboiled rice manufacturing wastewater through fish bioassay.

    PubMed

    Giri, Dipti Ramesh; Singh, Ekta; Satyanarayan, Shanta

    2016-01-01

    Short term aquatic bioassay has been developed into a useful tool in water quality management. These tests give information on comparative toxicity of several compounds. The objective of this study was to evaluate the acute toxicity of raw and anaerobically treated effluents of the parboiled rice manufacturing industry. The acute toxicity test was carried out by using the fish Lebistes reticulatus under laboratory conditions. LC50 values for 24, 48, 72 and 96 hours ranged between 4.6 and 7.0% for the raw parboiled rice manufacturing wastewater. Two anaerobic fixed film fixed bed reactors and two different media matrices, i.e. UV stabilized Biopac media and Fugino spirals, were used for the treatment of parboiled rice mill wastewater. Effluents from these two reactors depicted LC50 values in the range of 68-88% and 62-78% for Biopac and Fugino spiral packed reactors, respectively. From the results, it is evident that anaerobically treated effluents from Biopac packed reactor is marginally better than Fugino spiral packed reactor. Results subjected to statistical evaluation depicted regression coefficient of more than 0.9 indicating good correlation between the mortality and effluent concentration.

  12. Copper bioavailability in a coastal environment of Northern Chile: comparison of bioassay and analytical speciation approaches.

    PubMed

    Stauber, J L; Andrade, S; Ramirez, M; Adams, M; Correa, J A

    2005-11-01

    An integrated approach including chemical speciation analyses and microalgal bioassays was used to assess the impact of copper from copper mining on a coastal area in Northern Chile. Dissolved copper ranged from <1 microg l(-1) at reference sites to 48 microgl(-1) at sites close to the mine discharge. Dissolved copper at sites closest to the discharge always exceeded seawater complexing capacities determined by anodic stripping voltammetry (ASV), and consequently labile copper was always detected (1-37 microg l(-1)). Agreement between ASV-labile copper and copper retained by cation exchange (ALSA) columns was excellent. Measured labile copper also accurately predicted bioavailable copper determined by growth inhibition of Nitzschia closterium and enzyme inhibition in Dunaliella tertiolecta. Seawater from Caleta La Lancha had the highest dissolved and labile copper and was the most toxic to micro-algal growth and enzyme activity. Previous studies at this site confirmed it had the lowest level of biodiversity, suggesting that copper may have both direct and indirect effects on these communities.

  13. Application of biological safety index in two Japanese watersheds using a bioassay battery.

    PubMed

    Wei, Dongbin; Lin, Zhifen; Kameya, Takashi; Urano, Kohei; Du, Yuguo

    2008-07-01

    In order to integratedly evaluate the biological safety as a water quality index, an assessment method based on three toxicity tests (algae growth inhibition, daphnia immobilization and larval fish toxicity) was developed. In this study, the developed method was used to screen, evaluate and rank the biological safety of small rivers near agricultural, industrial and residential areas. Twenty-seven representative water samples were collected from the Kaname River watershed and the Hinata River watershed in Kanagawa Prefecture, Japan. The results indicated that (1) the biological safety of water from the Hinata River ranked much higher than those from the Suzu River and the Shibuta River due to less human activities, (2) the biological safety from outlets of paddy fields ranked much worse than those from point source discharges of toxic pollutants, (3) the use of pesticides significantly affected the water quality of nearby small rivers and ditches during the pesticide application season, (4) the effects of different kinds of pesticides could successfully be classified using one toxicity test component of the bioassay battery, and (5) there was no significant quantitative relationship between the toxicity and dissolved organic carbon (DOC) for the studied water samples. The toxicities of water samples in this study were in agreement with the concentrations of pesticides determined with chemical methods by other researchers, which demonstrated that the developed assessment method was reliable to screen site contaminated with organic chemicals for priority management.

  14. A chronic bioassay with the estuarine amphipod Corophium volutator: test method description and confounding factors.

    PubMed

    van den Heuvel-Greve, Martine; Postma, Jaap; Jol, Johan; Kooman, Hanneke; Dubbeldam, Marco; Schipper, Cor; Kater, Belinda

    2007-01-01

    Methods of conducting a chronic sediment toxicity test with the estuarine amphipod Corophium volutator are described. They consist of a 49-day exposure, after which mortality, growth and reproduction are determined. Pilot experiments were used to optimize test design parameters such as temperature, duration, feeding and refreshing regimes, and effects of indigenous organisms. By way of further validation, the present study focused on the effects of four different parameters: oxygen saturation, salinity, ammonium and nitrite. These confounding factors might play an important role especially if the test is used for risk assessment of field-contaminated sediments. It is concluded that the present experimental design is well suited for chronic sediment exposures with C. volutator. The test can be performed at a broad range of salinity values, provided that controls are performed at the same salinity. Results further demonstrate that with the endpoints growth and reproduction this chronic test procedure is a factor 7-18 more sensitive to ammonium and nitrate than the standardized acute bioassay (endpoint mortality).

  15. Assessment of the environmental quality of French continental Mediterranean lagoons with oyster embryo bioassay.

    PubMed

    Galgani, F; Senia, J; Guillou, J L; Laugier, T; Munaron, D; Andral, B; Guillaume, B; Coulet, E; Boissery, P; Brun, L; Bertrandy, M C

    2009-10-01

    In order to better understand environmental disturbances in the French coastal Mediterranean lagoons, we used an ecotoxicological approach based on the measurement of the toxicity of the sediments using oyster embryo bioassay that provides a basis for assessing the effects on the fauna of contaminants adsorbed on the sedimentary particles. The study covers all of the main lagoons of the French Mediterranean coasts of Languedoc Roussillon, Camargue, and Provence (Berre and Bolmon lagoons), where 188 stations were sampled. The toxicity tests provide evidence of variable levels of toxicity in sediments. Contaminated lagoons such as La peyrade, Le canet, and Ingrill and locally affected lagoons such as Bages-Sigean, Vaccares, Bolmon, and Berre have sampling stations with 100% of larval abnormalities during 24-h development. In all of the lagoons, the toxicity was mainly located close to local harbors and rivers. Salses Leucate (Languedoc roussillon) lagoon was found very clean, with no important toxicity. The results are discussed in terms of environmental disturbances of the coastal lagoons and with regard to the long-term monitoring of the impact of contaminants on the coastal environment.

  16. Primate polonium metabolic models and their use in estimation of systemic radiation doses from bioassay data

    SciTech Connect

    Fellman, A.

    1989-01-01

    A Polonium metabolic model was derived and incorporated into a Fortran algorithm which estimates the systemic radiation dose from {sup 210}Po when applied to occupational urine bioassay data. The significance of the doses estimated are examined by defining the degree of uncertainty attached to them through comprehensive statistical testing procedures. Many parameters necessary for dosimetry calculations, were evaluated from metabolic studies of {sup 210}Po in non-human primates. Two tamarins and six baboons were injected intravenously with {sup 210}Po citrate. Excreta and blood samples were collected. Five of the baboons were sacrifice at times ranging from 1 day to 3 months post exposure. Complete necropsies were performed and all excreta and the majority of all skeletal and tissue samples were analyzed radiochemically for their {sup 210}Po content. The {sup 210}Po excretion rate in the baboon was more rapid than in the tamarin. The biological half-time of {sup 210}Po excretion in the baboon was approximately 15 days while in the tamarin, the {sup 210}Po excretion rate was in close agreement with the 50 day biological half-time predicted by ICRP 30. Excretion fractions of {sup 210}Po in the non-human primates were found to be markedly different from data reported elsewhere in other species, including man.

  17. Selection of optimal measures of growth and reproduction for the sublethal Leptocheirus plumulosus sediment bioassay

    SciTech Connect

    Gray, B.R.; Wright, R.B.; Duke, B.M.; Farrar, J.D.; Emery, V.L. Jr.; Brandon, D.L.; Moore, D.W.

    1998-11-01

    This article describes the selection process used to identify optimal measures of growth and reproduction for the proposed 28-d sublethal sediment bioassay with the estuarine amphipod Leptocheirus plumulosus. The authors used four criteria (relevance of each measure to its respective endpoint, signal-to-noise ratio, redundancy relative to other measures of the same endpoint, and cost) to evaluate nine growth and seven reproductive measures. Optimal endpoint measures were identified as those receiving relatively high scores for all or most criteria. Measures of growth scored similarly on all criteria, except for cost. The cost of the pooled (female plus male) growth measures was substantially lower than the cost of the female and male growth measures because the latter required more labor (by approx. 25 min per replicate). Pooled dry weight was identified as the optimal growth measure over pooled length because the latter required additional labor and nonstandard software and equipment. Embryo and neonate measures of reproduction exhibited wide differences in labor costs but yielded similar scores for other criteria. In contrast, brooding measures of reproduction scored relatively low on endpoint relevance, signal-to-noise ratio, and redundancy criteria. The authors recommend neonates/survivor as the optimal measure of L. plumulosus reproduction because it exhibited high endpoint relevance and signal-to-noise ratios, was redundant to other reproductive measures, and required minimal time.

  18. Comparisons of uniform and discrete source distributions for use in bioassay laboratory performance testing

    SciTech Connect

    Scherpelz, R.I.; MacLellan, J.A.

    1987-09-01

    The Pacific Northwest Laboratory (PNL) is sending a torso phantom with radioactive material uniformly distributed in the lungs to in vivo bioassay laboratories for analysis. Although the radionuclides ultimately chosen for the studies had relatively long half-lives, future accreditation testing will require repeated tests with short half-life test nuclides. Computer modeling was used to simulate the major components of the phantom. Radiation transport calculations were then performed using the computer models to calculate dose rates either 15 cm from the chest or at its surface. For /sup 144/Ce and /sup 60/Co, three configurations were used for the lung comparison tests. Calculations show that, for most detector positions, a single plug containing /sup 40/K located in the back of the heart provides a good approximation to a uniform distribution of /sup 40/K. The approximation would lead, however, to a positive bias for the detector reading if the detector were located at the chest surface near the center. Loading the /sup 40/K in a uniform layer inside the chest wall is not a good approximation of the uniform distribution in the lungs, because most of the radionuclides would be situated close to the detector location and the only shielding would be the thickness of the chest wall. The calculated dose rates for /sup 60/Co and /sup 144/Ce were similar at all calculated reference points. 3 refs., 5 figs., 10 tabs.

  19. Evaluation of artificially-weathered standard fuel oil toxicity by marine invertebrate embryogenesis bioassays.

    PubMed

    Bellas, Juan; Saco-Álvarez, Liliana; Nieto, Óscar; Bayona, Josep María; Albaigés, Joan; Beiras, Ricardo

    2013-01-01

    wWeathering of petroleum spilled in the marine environment may not only change its physical and chemical properties but also its effects on the marine ecosystem. The objective of this study was to evaluate the toxicity of the water-accommodated fraction (WAF) obtained from a standard fuel oil following an environmentally realistic simulated weathering process for a period of 80 d. Experimental flasks with 40 g L(-1) of fuel oil were incubated at 18°C with a 14 h light:10 h dark photoperiod and a photosynthetically active radiation (PAR) intensity of 70 μE m(-2) s(-1). Samples were taken at four weathering periods: 24 h, 7, 21 and 80 d. WAF toxicity was tested using the sea urchin (Paracentrotus lividus) and mussel (Mytilus galloprovincialis) embryo-larval bioassays and the aromatic hydrocarbons levels (AH) in the WAF were measured by gas chromatography/mass spectrometry. In contrast with the classic assumption of toxicity decrease with oil weathering, the present study shows a progressive increase in WAF toxicity with weathering, being the EC(50) after 80d eightfold lower than the EC(50) at day 1, whereas AH concentration slightly decreased. In the long term, inoculation of WAF with bacteria from a hydrocarbon chronically-polluted harbor slightly reduced toxicity. The differences in toxicity between fresh and weathered fuels could not be explained on the basis of the total AH content and the formation of oxidized derivatives is suggested to explain this toxicity increase.

  20. Approaches to the choice of the test organisms for bioassay of the marine environment

    SciTech Connect

    Khristoforova, N.K.; Tyurin, A.N. |

    1995-12-31

    Regarding test organisms for assessment of water quality the present-day toxicologists usually give their preference to such practically important characteristics of species as easiness of laboratory cultivation, small number of endpoints measured and short duration of tests. The most often used indicators of the marine environment toxicity are: eggs, embryos, and larvae of invertebrates. This approach is based on a higher sensitivity of initial ontogenetic stages and is focused on abnormalities of fertilization and/or development. Taking different endpoints (appearance of fertilization membrane, gastrula, pluteus I, prodissoconch I, e.o.) as convenient guides gives species unequal opportunities for showing potential sensitivity because only initial stages (embryonal or larval) are used in practice. Moreover, neither case reaches the most critical final stage, namely the metamorphosis and settlement. It is quite possible that the proposed test on chitons, (Lepidozona albrechti and Ischnochiton hakadensis) can be considered as the most sensitive among the currently known marine bioassays because both species reach the juvenile stage in 4 days. The results show that MPC`s for fishery water bodies estimated by this test are 5 times less then the MPC`s for Cu, 10 times less for Cd and 50 times less for Zn and detergents.