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1
Widdowson, Alexandra. "Microbial toxicity testing of inorganic nanoparticles." Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=227625.
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NPs are toxic to a wide range of organisms across trophic levels; gram-positive and gram-negative bacteria (Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus and Escherichia coli), algae (Pseudokirchneriella subcapitata), crustaceans (Daphnia magna and Thamnocephalus platyurus), fish (rainbow trout, zebrafish, trout) and plants (Lactuca sativa L. and Raphanus sativus L). Due to their lack of target specificity, NPs may pose an environmental risk. The antibacterial properties of Ag and Cu nanoparticles (NP) are enhanced by their large reactive surface area, compared to bulk counterparts. Toxicity of NPs is attributed to their solubility and subsequent release of ions. However, the cytotoxic effects of NPs cannot always be attributed to the free ion fraction. The underpinning objective of this study was to link the response of microbial biosensors to detailed chemical analysis of NP dissolution products. NPs were suspended in Millipore water and in the presence of the steric stabiliser Na citrate and the resulting NP solubility characterised. Using chemical analysis this study quantified the flux of total dissolved metal (total [M]) and free metal ions [M+] from Ag and Cu NPs (Chapter 3). Two bioluminescent biosensors were used to assess the bioavailable metal fraction ([M]bio) of NP dissolution (Chapters 5 and 6). E. coli HB101 pUCD607 (bacterial) and M. citricolor (fungal) were chosen to represent NP toxicity across trophic levels using the same response mechanism. Additionally, the metal-induced bioreporter, P. fluorescens DF57-Cu15, was used to quantify the Cu bioavailability of Cu NP dissolution. By combining chemical and biological analysis this study inferred NP toxicity is not mass dependent, toxicity is dissolution dependent. Dissolution of Ag and Cu NPs in Millipore water was mostly in the [M+] form. This remained the case for Ag NPs in the presence of Na citrate. However, dissolution of Cu NPs in Na citrate was mostly as total [Cu]. This was due to Cu ions complexing readily with citrate. Toxicity of Ag NP dissolution in Millipore water was concentration dependent. Total [Ag] correlated with E. coli HB101 toxicity response. The addition of Na citrate reduced Ag NP dissolution and therefore reduced toxicity to E. coli HB101. M. citricolor was less sensitive than E. coli HB101 to the dissolution products of Ag NPs in Millipore water. However, the sensor was more sensitive to the dissolution of Ag NPs in Na citrate than E. coli HB101. Cu NPs were chemically stable in Millipore water. The bioreporter P. fluorescens DF57-Cu15 was not induced by Millipore suspensions and E. coli HB101 was not inhibited. However, M. citricolor responded to [Cu]bio of Millipore suspensions with a maximum 54% inhibition of bioluminescence. P. fluorescens DF57-Cu15 was induced by the dissolution products of Cu NPs with the addition of Na citrate, only at high NP concentrations (> 500 mg/L). [Cu]bio of the Na citrate suspensions was toxic to E. coli HB101. However, toxicity was greater for M. citricolor with a maximum biosensor inhibition of 83%. There was no correlation between total [Cu], [Cu2+] or [Cu]bio with the response of either biosensors nor the bioreporter. Interpretation of Ag and Cu NP toxicity was made possible by the combining of chemical and biological toxicity assessment. Dissolution of Ag NPs suspended in Millipore water could be attributed as the main factor in toxicity to E. coli HB101 because of the knowledge gained by chemical analysis. It also allowed the conclusion that NP dissolution was a key factor to toxicity in all cases but biological assessment attributed NP assimilation as a contributing factor. Biological assessment is vital as no chemical analysis can quantify [M]bio, especially when [M]bio was perceived differently by biosensors of different trophic levels and modes of action. Combining chemical and biological assessment in this study was essential for interpreting NP toxicity.
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Macdonald, Niall Patrick. "Microsystems manufacturing technologies for pharmaceutical toxicity testing." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/5070/.
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To meet the demands of political, ethical and scientific pressures on animal testing, research into possible alternatives is required. Data obtained with animal models often cannot be related to humans. Testing with current cell-based assays, microdosing and pharmacokinetic models contribute to reducing animal testing and improving the drug development process. Micro-fabrication and rapid prototyping techniques offer potential solutions to reduce the need for animal toxicity testing. The aim of this research was to develop biological platforms for in vitro toxicity testing to provide physiologically relevant, high-throughput solutions to reduce animal testing. This was achieved by investigating and integrating microfabrication methods of microfluidics, dielectrophoresis and additive manufacturing. Three approaches were taken: (i) micro-pattern protein arrays for primary hepatocyte cell culture enclosed within microfluidics devices for high-throughput toxicity testing. It was observed that hepatocytes attached to the micro-pattern within microfluidics and maintained viability, however liver specific functions observed by florescence assays, the P450 enzymes, were observed to be reduced compared to Petri dish conditions. (ii) A biomimetic dielectrophoretic cell patterning technique to form liver lobule-like tissue structures within agar on a paper substrate was developed for toxicity testing. Observation of these biomimetic micro liver structures showed high viability (80-90%) and an increase in liver specific function marker albumin protein (20%) compared to control samples after 48 hours. (iii) Rapid prototyping methods were explored with regard to fabrication of microfluidic chips for the automated trapping, imaging and analysis of zebrafish embryos. Monolithic microfluidic chips for zebrafish were developed to be suitable for optical based toxicity assays. The biocompatibility of 3D printed materials was investigated. A method to render the photopolymer Dreve Fototec 7150 compatible with zebrafish culture was observed to provide 100% viability. Future development of this research will aim to (i) develop the liver lobule-like system to use layers of multiple cell types to form complex micro-liver models using additive manufactured microfluidic systems for toxicity testing. (ii) Automation of zebrafish handing using additive manufactured microfluidic devices for in-situ analysis of dechorionated zebrafish for high-throughput toxicity studies.
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Taylor, Nadine Suzanne. "Novel approaches to toxicity testing in Daphnia magna." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/668/.
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Current regulatory risk assessment strategies have several limitations, such as linking subcellular changes to higher-level biological effects, and an improved knowledge-based approach is needed. Ecotoxicogenomic techniques have been proposed as having the potential to overcome the current limitations, providing greater mechanistic information for ecotoxicological testing. In this thesis, metabolomics is explored as a novel method for toxicity testing using Daphnia magna. Initially I evaluated the potential application of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) based metabolomics for use in regulatory toxicity testing. Subsequently, I aimed to use this approach to discriminate between toxicant modes of action (MOA) and to link toxicant induced metabolic effects to reduced reproductive output in D. magna. FT-ICR MS metabolomics was determined to be a feasible approach for toxicity testing of both whole-organism homogenates and haemolymph of D. magna. It is capable of discriminating between life-stages of D. magna as well as determining toxicant-induced metabolic effects. Highly predictive multivariate classification models were capable of significantly discriminating between four different toxicant MOAs; achievable in both haemolymph and whole-organism extracts, with the latter being the more information-rich sample type. Multivariate regression models were predictive of reduced reproductive output in D. magna following toxicant exposure, and determined that a metabolic biomarker signature was significantly able to predict the reproductive output of D. magna. Ultimately this research has concluded that an FT-ICR MS metabolomics approach for use in regulatory toxicity testing using Daphnia magna is both viable and can provide valuable information.
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Payne, Chris 1971. "Phylogenetic trends in phytoplankton resistance to Cd and Cu toxicity." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24033.
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Some species of marine phytoplankton are believed to be more tolerant of high concentrations of trace metals than others, but no conclusive test of this hypothesis has been conducted. Eleven species of phytoplankton representing 5 classes were grown in Aquil medium containing Cd$ sp{2+}$ concentrations between 10$ sp{-9.85}$ and 10$ sp{-6.84}$ M. Growth rates and intracellular concentrations of Cd, C, N and S were measured. Cadmium quotas (mol Cd/litre-cell volume) were lower in members of Bacillariophyceae than in Chlorophyceae, Prymnesiophyceae, Dinophyceae and Cyanophyceae (ANOVA, p $<$ 0.001). Cellular C:S molar ratios decreased in phytoplankton grown at high (pCd 7.37-6.84) compared to low Cd (no added Cd), as S/litre-cell volume increased. Similar results were observed for C:N molar ratios. In two species that were examined, C:S ratios decreased as a linear function of increasing Cd concentration. Mean Cd$ sp{2+}$ concentration that reduced growth rate to 50% of maximum (pCd$ sp{50})$ was not significantly different among phytoplankton classes (ANOVA, p $<$ 0.05). When these experimental data were combined with pCd$ sp{50}$s calculated from published sources, Chlorophyceae were found to be the most resistant class (ANOVA, p $<$ 0.01). Cadmium and Cu resistance (pCd$ sp{50}$ and pCu$ sp{50})$ were correlated (r = 0.52, p $<$ 0.05), suggesting co-tolerance of phytoplankton to toxic levels of these metals. Chlorophyceae were most tolerant and Cyanophyceae the least tolerant of Cu (ANOVA, p $<$ 0.01). No significant differences were observed among Bacillariophyceae, Prymnesiophyceae, and Dinophyceae, which were of intermediate sensitivity to both metals. The results confirm the existence of a phylogenetic dependence of resistance to trace metal toxicity in phytoplankton.
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Adler, Sarah. "The use of pluripotent cells in developmental toxicity testing." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976069806.
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Radburn-Smith, Marcus Alexander. "Novel in vitro models and methods for ocular toxicity testing." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443263.
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Yang, Jie. "Three dimensional perfused cell culture for in vitro toxicity testing." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:a72b7015-cc57-4bb8-904a-a5a88e2194f1.
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This study describes the development of a novel method of three dimensional perfused cell culture for in vitro toxicity testing. Multiple parallel perfused microbioreactors (TissueFlexTM) were adopted to provide a well-controlled cell culture environment. Alginate and collagen type I, commonly used as hydrogel scaffolds to support cell culture, were tested as the scaffolding materials for this application. Alginate supports cell proliferation, but does not support cell attachment. Collagen gel (type I), good for cell attachment but with poor mechanical strength, could be used at the high concentration of 5mg/ml to prevent the degradation of the gel. Improvement of collagen biomechanical property by a purpose-designed compressor to physically induce cross-linking showed promising results and merits further study. The suitability of alamarBlue® assay, a common non-toxic non-destructive viability assay method, was confirmed for this study and the protocol was optimised. To demonstrate the effectiveness of three dimensional perfused cell culture, human mesenchymal stem cells (MSC) seeded in collagen type I were employed to test the cell inhibition of two antibiotics, trimethoprim and pyrimethamine. The results displayed the perfusion system has greater advantage and sensitivity than the static system, as does these of 3D scaffolds, compared with 2D. Such differences are related to the continuous supply of fresh culture medium to keep cells at a stable pH, temperature, oxygen, and a more physiological like environment. The cytotoxicity of two stereoisomer compounds, obtained confidentially from Pfizer. Ltd., was assessed using the developed method and compared to conventional 2D static and perfused culture by using rat adipose mesenchymal stem cells. The results successfully distinguished toxic and non-toxic compounds and also demonstrated that the 3D perfused system improved the prediction of drug toxicity over 2D culture. 3D perfused bioreactors were applied to hepatotoxicity study using freshly isolated rat hepatocytes. Only algimatrixTM supported hepatocyte spheroid formation among those tested including collagen type I, alginate beads, poly lactic acid fibres, and AlgimatrixTM. A new variation of TissueFlexTM bioreactor with micro-patterned surface, designed specifically for hepatocyte self-assembly culture without use of any scaffold, was tested. The results demonstrated that, compared with the standard sandwich culture, the self-assembly culture in the micro-patterned bioreactors showed high cell viability, biomarkers expression, as well as more physiological immunocytochemistry. Moreover, the differential gene expression indicated that self-assembly culture could provide more relevant information regarding metabolising processes than the 2D sandwich culture, which would potentially improve hepatotoxicity prediction. In conclusion, 3D perfused cell culture for in vitro toxicity testing improved the predictivity, reliability and physiological relevance of drug toxicity compared to traditional 2D culture.
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Naidoo, Vinasan. "Diclofenac in Gyps vultures a molecular mechanism of toxicity /." Electronic thesis, 2007. http://upetd.up.ac.za/thesis/available/etd-07032008-093716/.
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Mitchell, Roger Dale 1955. "Systemic indicators of inorganic arsenic toxicity in several species." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276678.
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Seven prospective biological indicators of systemic toxicity were examined at time points ranging from 15 minutes to 24 hours using male Sprague-Dawley rats, B6C3F1 mice, Golden-Syrian hamsters and Hartley guinea pigs following intraperitoneal dosing with 0.1 mg/kg and 1.0 mg/kg sodium arsenite. Rats and mice were also dosed with 1.0 mg/kg sodium arsenate. Pyruvate dehydrogenase (PDH) activity was significantly depressed at early time points in mice, hamsters and guinea pigs and at later time points in rats dosed with arsenic (III). Rats and mice dosed with arsenic (V) also exhibited PDH depression at early time points. Uroporphyrin and coproporphyrin excretion was elevated in mice following arsenic (III) dosing. Coproporphyrin excretion was elevated in rats following arsenic (V) dosing. Blood glucose, creatinine, urea nitrogen and creatinine were unchanged by arsenic dosing. Based upon the amount and types of biological responses observed, the mouse appears to be the most sensitive animal model for the further study of arsenic toxicity.
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Cikutovic, Salas Marcos A. "Pathologies in earthworms: sublethal biomarkers of xenobiotic toxicity." Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc798085/.
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This research is part of an overall program to develop and use a suite of acute and sublethal toxicity biomarkers, and testing protocols for use in assaying potential effects of complex mixtures of xenobiotics such as found in soils containing agricultural biocides and petrochemical wastes dredged sediments, and hazardous waste sites (HWS). The purpose of this study was to evaluate four biomarkers of sublethal pathology that could be used in an integrative model of multiple toxicity endpoints with the earthworm Lumbricus terrestris.
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Juchelka, Charlotte Milada. "Rapid toxicity assessment using ingestion rate as a sublethal biomarker." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/25413.
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Burbank, Susan Elizabeth. "Development of rapid toxicity tests using enzyme inhibition as sulethal biomarker." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/25401.
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Middendorf, Paul Joseph. "Development and evaluation of toxicity tests using Caenorhabditis elegans with reproduction, mutation, lethality, and behavior as end points." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/25201.
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Lai, Keng Po. "Study on the environmental contamination and mechanistic toxicology of 2,3,7,8-tetrachlorodibenzo-p-dioxin." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/527.
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Mochan, Daria Galina. "Evaluation of a Rapid-screening Toxicity Test Using the Ciliate, Colpoda inflata (Stokes): Sensitivity and Bioavailability to Model Compounds." PDXScholar, 1996. https://pdxscholar.library.pdx.edu/open_access_etds/5165.
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Standard toxicity tests often require high costs for maintaining healthy cultures, so few test species are employed in routine ecotoxicological analysis. An alternative is the "battery of tests" approach involving using rapid toxicity tests for screening. Rapid-screening toxicity tests must display organism sensitivity, similarity in responses to other test organisms, relevancy to many circumstances, and repeatability. Protozoa are ideal candidates for rapid-screening bioassays. They are cosmopolitan, play important roles in ecosystems, and have high reproductive rates. Many protozoa can form a resting stage (cyst) that remains viable during adverse conditions, eliminating the need for maintaining continuous cultures for testing. The main objective of this research was to evaluate the soil ciliate, Colpoda inflata (Stokes), as a bioassay organism in rapid-screening tests by determining its sensitivity to a variety of model compounds. These tests were based on the principle that exposure to a toxic compound would negatively affect population growth. To test for sensitivity, C. inflata was exposed to different levels of dissolved organic carbon in test media for each compound tested. C. inflata was expected to be more sensitive to toxicants in an inorganic medium than in media with high organic carbon content. Data were analyzed by determining the median tolerance limit for inhibition of population growth (IG50) relative to controls. IG50 values of the eight model compounds tested varied considerably. C. inflata growth was not significantly affected by 2,4-D or malathion. C. inflata showed differences in sensitivity between organic and inorganic media for the toxic metals tested and the order of toxicity corresponded to those found in standard tests. A significant difference occurred between the test media and the pesticide PCP, where growth was not inhibited in the organic medium; in the inorganic medium the IG50 was 0.269 mg/L. No significant effect of test media was found for ammonia or SDS. Compared to several published toxicity results, C. inflata proved more sensitive overall than other rapid-screening tests and many standard acute toxicity tests. Results of this study show that this rapid-screening toxicity test is sensitive, repeatable, and provides information similar to traditional standard toxicity tests.
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Nielsch, A. S. "Effects of prostaglandins and prostaglandin synthetase inhibitors on liver toxicity." Thesis, University of Aberdeen, 1987. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU499301.
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A total of 22 non-steroidal anti-inflammatory drugs and derivatives were added to microsomes to study the denaturation of cytochrome P-450 to cytochrome P-420 in the absence of an NADPH-generating system. There was a highly significant correlation among the different compounds between the extent of denaturation of cytochrome P-450 and their surfactant potency. Endotoxin administration to rats caused a maximum decrease in hepatic microsomal enzymes after 24 hours. Significant decreases in cytochrome P-450 (40%), cytochrome b5 levels (22%), aminopyrine N-demethylase (31%) and biphenyl 4-hydroxylase (54%) activities were obtained. Concomitant intravenous injection of 16,16-DMPG F2 and 16,16-DMPG E2 prevented some of the endotoxin-induced changes in hepatic microsomal enzymes. Three days treatment with cocaine was required to obtain hepatic damage in mice. Decreases in cytochrome P-450 content (41%), aminopyrine N-demethylase (31%) and FAD-monooxygenase (35%) activities were obtained, when compared to saline treated mice. The serum enzyme activities were markedly increased (SGOT 13-fold and SOCT 44-fold). Histological changes in form of centrilobular necrosis and fatty changes were present. Repeated subcutaneous administration of iloprost or synthetic prostaglandins just before cocaine prevented some of the hepatic lesions. Iloprost was found to be a better hepatoprotective agent than synthetic prostaglandins against the cocaine mediated liver toxicity. Carbon tetrachloride administration to mice produced similar lesions to those obtained with cocaine. Administration of iloprost prevented some of the lesions caused by carbon tetrachloride, giving a partial protection to the carbon tetrachloride-induced decrease in cytochrome P-450 and the increase in SGOT. Iloprost also partially prevented the carbon tetrachloride mediated centrilobular necrosis.
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Bramble, Lisa Anne. "Utilization of mitochondrial and microsomal metabolism for the assessment of toxicity." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03122009-040409/.
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Lestari, Fatma Safety Science Faculty of Science UNSW. "Development of in vitro toxicity methods for fire combustion products." Awarded by:University of New South Wales. School of Safety Science, 2006. http://handle.unsw.edu.au/1959.4/24280.
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A large range of polymers are used in building and mass transport interiors which released more toxic products during combustion. This work explores the cytotoxicity of selected chemicals and smoke derived from materials combustion. A selection of polymers and fiberglass reinforced polymer (FRP) composites used in building and railway carriage interiors including: polyethylene (PE), polypropylene (PP), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), melamine plywood, and two FRPs were studied. A small scale laboratory fire test using a vertical tube furnace was designed for the generation of combustion products. The volatile organic compounds were identified using ATD-GCMS (Automatic Thermal Desorption-Gas Chromatography Mass Spectrometry). The in vitro techniques were developed for human cells exposure to fire effluents including the indirect (impinger) and direct (air/liquid interface using Harvard Navicyte Chamber) exposure. Cytotoxic effects were assessed based on cell viability using a range of in vitro assays. Human skin tissue was also used as preliminary study to assess the toxic effects at the tissue level. A minor change in the cellular function of the skin from the exposure of PMMA combustion products was observed. The combustion study was conducted under different burning stage of fire: non-flaming and flaming combustion. Results suggested that PVC was the most toxic material for both non-flaming (IC50 1.24 mg/L) and flaming combustion (IC50 1.99 mg/L). The degree of toxicity generated depends on the fire stage: non-flaming or flaming combustion. Some materials revealed to be more toxic under flaming combustion (PP, PC, FRPs), whilst others (PVC, PMMA, PE, and melamine plywood) appear to be more toxic under non-flaming combustion. A strong correlation was shown between the change in toxicity as measured by IC50 and TLC and the change in concentration of volatile organic compounds (VOCs) and particulates. A comparison between in vitro data versus published in vivo combustion data indicated the in vitro results to be more sensitive than animal toxicity data. The outcome of this study has the potential for an alternative method to current fire toxicity standard, whilst providing more accurate toxicity information for fire safety professionals, materials manufacturer, building designers and consumer safety data.
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Lawrence, J. N. "Cryopreservation and toxicity studies with cultured rat and human hepatocytes." Thesis, University of Surrey, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233123.
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Bruschi, Sam A. "Investigations into mechanisms of paracetamol-induced toxicity using ìn vitro' systems /." Title page, abstract and table of contents only, 1987. http://web4.library.adelaide.edu.au/theses/09PH/09phb192.pdf.
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Palmer, Gabrielle. "The application of lux-marked bacteria for terrestrial ecotoxicity testing." Thesis, University of Aberdeen, 1999. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU117731.
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The introduction of lux genes, able to express bioluminescence, into terrestrial bacteria enabled the optimisation of a bioluminescence-based bioassay that was environmentally relevant. Individual assay parameters such as growth phase, cell washing, lyophilisation, pH tolerance and temporal response to a range of metal and xenobiotic pollutants were evaluated. The effects of a range of pollutants upon the metabolic response of the lux-marked organisms were assessed using declines in bioluminescence. The lux -based bioassay proved more sensitive to the sub-lethal effects of metal pollutants than tests relying on culturability. Uncontaminated soils were spiked with metal and xenobiotic solutions both as single pollutants and in combination with other contaminants. Relative toxicity of metal and xenobiotic pollutants in soil systems were investigated using ecotoxicity assays based upon lux-marked constructs of Rhizobium leguminosarum biovar trifolii (an important associative nitrogen fixer) and the respiration of the microbial community. The lux-marked bioassay proved to be more sensitive than the community microbial assay to the presence of multiple contaminants at sub-lethal concentrations. The relative toxicities of metal and organic xenobiotic compounds were shown to be time dependent and better represented using chronic assaying of lux-marked microorganisms. Following a field trial involving the application of paper mill sludge to land and subsequent crop failure a rapid diagnosis of soil pollutants was required. A suite of ecotoxicity assays including lux-based bioassays, respirometry and enzyme activity were used to assess the toxicity of paper mill sludge to the soil microbial biomass. The selected lux-marked soil bacteria showed potential for use as rapid, field-based screening techniques to provide early warning of the potential hazards of waste application.
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Davies, Joanna. "Synthesis of zwitterionic compounds for aquatic toxicity testing for QSAR correlation studies." Thesis, Swansea University, 2003. https://cronfa.swan.ac.uk/Record/cronfa42651.
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22 zwitterionic compounds (10 short-chain surfactants; 12 non-surfactants) were synthesised obeying the general formula R-N+(CH3)2(CH2)nSO3', where n = 2 to 4, by reacting the corresponding N, N-dimethylamines with either sodium-2-chloroethane sulfonate (n = 2), 1, 3- propanesulfonate (n = 3) or 1,4-butanesulfonate (n = 4). The R group varied from a C6 to C12 alkyl chain, to a phenylalkyl unit bearing a Cl to C4 chain and finally to a phenylpropyl unit with a C4 to C6 para-substituted alkyl group. Octanol/water partition coefficients of the 22 sulfobetaines were determined by a conventional stir-flask procedure. The amount of solute in both the octanol and water layer was quantified using a reverse-phase HPLC technique. A UV detection mechanism was employed for those sulfobetaines that possessed a suitable chromophore for UV detection and an electrospray ionisation mode of detection was used for the analysis of those sulfobetaines that lacked a chromophore suitable for UV detection. Acute aquatic toxicity to the aquatic invertebrate, Daphnia magna Straus, was reported as log (l/EC50). The EC50 values were determined experimentally using a standard Acute Immobilisation Test recommended by the OECD Guideline 202 and the internal Unilever document, Ecotoxicology SOP 019 11. A log P-based QS AR was then derived which was found to be analogous to the standard polar narcosis equation, suggesting that zwitterionic sulfobetaines act as polar narcotics. Experimental log P determined by the stir-flask procedure and the rules of Rekker and Roberts for the calculation of log P for quaternary ammonium compounds of the cationic type, were then used in the derivation of key fragment values and interaction factors for use in log P calculations of sulfobetaines using the Leo and Hansch approach. Furthermore, log P predictions provided by KowWin, a computerised program developed by the Syracause Research Cooperation, were suitably amended to take into consideration our experimental results. Finally, an investigation into the suitability of the phospholipophilicity parameter, log k'lAM, for defining aquatic toxicity was performed and the efficacy of using this parameter and log P to predict aquatic toxicity was compared. In addition, other chromatographic methods for estimating log P were investigated. These include the indirect reverse-phase HPLC method, the direct reverse-phase HPLC method and Counter Current Chromatography.
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Everitt, Victoria Jane. "The use of indigenous macroinvertebrates and Daphnia pulex in acute toxicity testing." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1005483.
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Aquatic toxicology has been identified as a valuable tool in the identification and management of chemical pollution in aquatic ecosystems. Standardised methodologies for acute aquatic bioassays have been adopted from international agencies. As a result of these standard methods, the use of laboratory cultured organisms for toxicity testing has been more popular than that of indigenous field-caught organisms. Included in these adopted methods are those for the cultured crustacean Daphnia pUlex. D.pulex is adapted to living in standing water and the suitability of this species to determine toxic effects for South African riverine environments, which are largely flowing, has been questioned. Thus this thesis is a case-study ofthe use of D.pulex and indigenous site-specific macroinvertebrates as toxicity test organisms for setting acute water quality guidelines to protect aquatic ecosystems. The study highlights site-specific problems such as reference sites and organism identification. The acute tolerance of selected indigenous invertebrates was compared to that of D. pulex, using both a single-substance reference toxicant (zinc) and selected whole efiluents. The significance of source population and culture age as a potential source of biological variability between D.pulex cultures was also investigated. D.pulex cultures have been initiated in South Africa from females collected from a number of different local populations; also it is assumed that no genetic change (due to mutation) occurs within a D.pulex culture over time. In order to establish if source population and culture age are a source of biological variability between D.pulex experiments, the acute tolerJuce to zinc of two different D.pulex populations and three different generations within a population were compared. Due to experimental variability results were inconclusive, and differences in tolerance as a result of population difference or culture age could not be determined with confidence. The acute tolerance of D.pulex to a single reference chemical (zinc) and selected whole efiluents was compared to that of selected indigenous invertebrates. Acute 48 h D.pulex zinc tolerance (LC50 range: 0.22 - 0.60 mg/l Zn) was found to be more sensitive than acute 96 h tolerances shown by mayfly species A.fconurus peringueyi (Heptageniidae) (LC50: 17.42 mg/l Zn), Euthrauluselegans (Leptophlebiidae) (LC50: 0.98 mg/IZn), Ba~tidae (LC50: 0.94mg/IZn) and shrimp, Caradina nilotica (Atyidae) (LC50: 3.17 mg/l Zn). This result suggests that guidelines for zinc set using D.pulex will protect the selected indigenous invertebrates. Selected whole eftluents were not acutely toxic to either D.pulex or selected indigenous invertebrates. These experiments were used as a case study for method development regarding the comparative use of D.pulex and indigenous invertebrates in acute whole eftluent toxicity testing. Finally, it is recommended that a suite of indigenous organisms (e.g. macroinvertebrates, fish and algae), as well as laboratory cultured D.pulex, be used in the initial setting of guidelines and that D.pulex be used for routine compliance monitoring. It is futher recommended that a suite of available monitoring methods, such as chemical and biomonitoring methodologies, be used in conjuction with toxicity testing in water quality management.
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Fortner, Jason C. "Illuminating whole effluent toxicity testing : ultraviolet radiation, phototoxicity, and PAH-contaminated groundwater /." Online version, 2009. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=314&CISOBOX=1&REC=10.
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Willetts, Rachel. "Development of a co-culture model of the human lungs for toxicity testing and identification of biomarkers of inhalation toxicity." Thesis, Aston University, 2012. http://publications.aston.ac.uk/16429/.
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The airway epithelium is the first point of contact in the lung for inhaled material, including infectious pathogens and particulate matter, and protects against toxicity from these substances by trapping and clearance via the mucociliary escalator, presence of a protective barrier with tight junctions and initiation of a local inflammatory response. The inflammatory response involves recruitment of phagocytic cells to neutralise and remove and invading materials and is oftern modelled using rodents. However, development of valid in vitro airway epithelial models is of great importance due to the restrictions on animal studies for cosmetic compound testing implicit in the 7th amendment to the European Union Cosmetics Directive. Further, rodent innate immune responses have fundamental differences to human. Pulmonary endothelial cells and leukocytes are also involved in the innate response initiated during pulmonary inflammation. Co-culture models of the airways, in particular where epithelial cells are cultured at air liquid interface with the presence of tight junctions and differentiated mucociliary cells, offer a solution to this problem. Ideally validated models will allow for detection of early biomarkers of response to exposure and investigation into inflammatory response during exposure. This thesis describes the approaches taken towards developing an in vitro epithelial/endothelial cell model of the human airways and identification biomarkers of response to exposure to xenobiotics. The model comprised normal human primary microvascular endothelial cells and the bronchial epithelial cell line BEAS-2B or normal human bronchial epithelial cells. BEAS-2B were chosen as their characterisation at air liquid interface is limited but they are robust in culture, thereby predicted to provide a more reliable test system. Proteomics analysis was undertaken on challenged cells to investigate biomarkers of exposure. BEAS-2B morphology was characterised at air liquid interface compared with normal human bronchial epithelial cells. The results indicate that BEAS-2B cells at an air liquid interface form tight junctions as shown by expression of the tight junction protein zonula occludens-1. To this author’s knowledge this is the first time this result has been reported. The inflammatory response of BEAS-2B (measured as secretion of the inflammatory mediators interleukin-8 and -6) air liquid interface mono-cultures to Escherichia coli lipopolysaccharide or particulate matter (fine and ultrafine titanium dioxide) was comparable to published data for epithelial cells. Cells were also exposed to polymers of “commercial interest” which were in the nanoparticle range (and referred to particles hereafter). BEAS-2B mono-cultures showed an increased secretion of inflammatory mediators after challenge. Inclusion of microvascular endothelial cells resulted in protection against LPS- and particle- induced epithelial toxicity, measured as cell viability and inflammatory response, indicating the importance of co-cultures for investigations into toxicity. Two-dimensional proteomic analysis of lysates from particle-challenged cells failed to identify biomarkers of toxicity due to assay interference and experimental variability. Separately, decreased plasma concentrations of serine protease inhibitors, and the negative acute phase proteins transthyretin, histidine-rich glycoprotein and alpha2-HS glycoprotein were identified as potential biomarkers of methyl methacrylate/ethyl methacrylate/butylacrylate treatment in rats.
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Arnegard, Matthew E. "Toxicant-releasing substrates : a new method for delivering copper to microbial communities in SITU /." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-12162009-020200/.
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Davies-Coleman, H. D. (Heather D). "The growth and reproduction of the freshwater limpet Burnupia stenochorias (Pulmonata, Ancylidae), and an evaluation of its use as an ecotoxicology indicator in whole effluent testing." Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1005389.
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For the protection of the ecological Reserve in South Africa, the proposed introduction of compulsory toxicity testing in the licensing of effluent discharges necessitates the development of whole effluent toxicity testing. The elucidation of the effects of effluent on the local indigenous populations of organisms is essential before hazard and risk assessment can be undertaken. The limpet Burnupia stenochorias, prevalent in the Eastern Cape of South Africa, was chosen to represent the freshwater molluscs as a potential toxicity indicator. Using potassium dichromate (as a reference toxicant) and a textile whole effluent, the suitability of B. stenochorias was assessed under both acute and chronic toxicity conditions in the laboratory. In support of the toxicity studies, aspects of the biology of B. stenochorias were investigated under both natural and laboratory conditions. Using Principal Component and Discriminant Function Analyses, the relative shell morphometrics of three feral populations of B. stenochorias were found to vary. Length was shown to adequately represent growth of the shell, although the inclusion of width measurements is more statistically preferable. Two of the feral populations, one in impacted water, were studied weekly for 52 weeks to assess natural population dynamics. Based on the Von Bertalanffy Growth Equation, estimates of growth and longevity were made for this species, with growth highly seasonal. Age is not easily discerned from shell size. Egg laying occurred all year round, with early summer (peak egg lay), mid summer (a second, smaller peak in egg lay), and winter (limited presence of eggs) phases. In toxicity testing, consideration is given to the choice of the test organism based on age and sexual development. Consequently, the sexual development of B. stenochorias relative to shell length was determined with the aid of histological examinations of transverse sections of limpets, of all sizes, collected over one year. Limpets less than 3mm shell length were found to be immature in the development of the oocytes and spermatozoa, and were later chosen for acute toxicity tests. A laboratory diet was developed, for both culturing and maintaining of the limpets during toxicity tests; however, the diet requires optimisation. Under laboratory conditions, growth was linear, and individual fecundity highly variable. Successful methods for the collection of limpets from naturally occurring populations, and their acclimation to the laboratory were developed. Three B. stenochorias populations, representing different hydrological and water quality conditions, were compared to a laboratory population (maintained for three years) in their responses to the textile whole effluent and potassium dichromate. Under acute conditions, variability of mortality between limpet populations and between seasons was consistent with acceptable international standards. However, seasonal differences between feral limpets were apparent, with early summer limpets significantly more susceptible to both potassium dichromate and textile effluent than winter limpets. Although mortality occurred within the effluent at all concentrations, no 96 hour LC₅₀ values were obtained. The chronic toxicity effects of the textile whole effluent were assessed over the entire life cycle of B. stenochorias, based on survival, growth and reproductive effects. Lower concentrations of effluent (# 10%) gave greater variability of responses and toxicity than higher concentrations, with a 43 day LC₅₀ of 3.9% effluent. The No Observed Effect Concentrations for survival (over 43 days) were calculated in consecutive years as 0.1% and 1% effluent. Survival is considered a useful tool for determining toxicity endpoints using B. stenochorias. Limpet growth remained linear in effluent, with an apparent stimulation of growth at the 3-10% effluent concentration, confusing the toxicity and variability assessments. The possible addition of nutrients from the effluent points to either a potential inadequacy of the food quality provided in the chronic assessment, or the presence in the effluent of growth stimulants. Growth was also found to be too variable to allow adequate statistical conclusions about the toxicity of the effluent, although it is suggested that growth may be useful in the assessment of single compounds. Despite large individual variability in fecundity, statistical differences were discernible between effluent concentrations. The application of fecundity of B. stenochorias in hazard assessment therefore warrants further investigation. It was concluded that an assessment of textile whole effluent toxicity to B. stenochorias over an entire life cycle, and an F1 generation, is unnecessary. The development of the bucket/plastic bag method for both acute and chronic toxicity assessment of B. stenochorias was useful. In the final assessment of the usefulness of B. stenochorias as a toxicity indicator, toxicity endpoints were compared with those of the standard laboratory organism Daphnia pulex. Both in acute and chronic toxicity, B. stenochorias was found to be more sensitive. B. stenochorias is therefore considered valuable as a South African freshwater molluscan ecotoxicological indicator, with a place in hazard assessment, although further development and research is necessary before the limpet can be effectively used.
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Mitchell, Joy Lynn. "Rapid toxicity assessment using esterase enzyme activity of several microalgal species." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/24912.
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Shannon, Robert David. "Evaluation of a mitochondrial test for the determination of chemical toxicity." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43054.
Full textAbstract:
The feasibility of using rat liver mitochondria respiratory parameters
as a short-term toxicity test was investigated. Mitochondrial fractions were
exposed to six concentrations of five chlorophenols. Respiratory parameters
were measured and compared to control experiments. The toxicity of the
chlorophenos, measured by the 50% uncoupling concentration (UC50),
increased with increasing chloro substitution.
The UC50 values for the five chlorophenols were compared to six
physicochemical parameters for the same chlorophenols and high degrees of
correlation were found (r >/- 0.890). The highest correlation coefficient
obtained was with the octanol-water partition coefficient. UC50 values were
also compared to nine currently existing short-term toxicity tests. High
degrees of correlation were obtained with several of these tests, including
bacterial and fish bioassays.
From the results of these experiments, the measurement and use of
mitochondria respiratory parameters as a short-term toxicity test appears to
offer an alternative to currently used short-term toxicity tests, particularly
with chemicals having physicochemical characteristics similar to
mitochondria uncouplers.Master of Science
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Thomas, David J. L. "Understanding the causes of toxicity in treated landfill leachate through whole effluent testing." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/5584.
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Landfill leachate is collected and treated before discharge to protect the environment from a potential toxic cocktail of substances. In the U.K. biological treatment is the favourite technology for rendering landfill leachate safe due its simple design, effective handling of varying chemical loads and relatively low operating costs. Biological treatment is effective at reducing the concentrations of ammoniacal-nitrogen and the biological oxygen demand (BOD) to acceptable levels for discharge. Even though the ammoniacal-nitrogen and BOD levels have been reduced there still remains a considerable quantity of refractory organic chemicals and inorganic ions. Heavy metals tend be present in very low concentrations. A view has developed that these effluents potentially pose a risk to the aquatic environment due to the presence of these compounds. Cont/d.
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Brown, Rebecca Jayne. "Development of culture and toxicity testing methods for the freshwater copepod Bryocamptus zschokkei." Thesis, University of Plymouth, 2001. http://hdl.handle.net/10026.1/2085.
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The aim of this thesis was to evaluate the use of a meiofaunal copepod as a test species for assessing the developmental and reproductive effects of toxicants relevant to freshwater ecosystems. The harpacticoid copepod Bryocamptus zschokkei was chosen as a candidate test species as it possesses several attributes (widespread distribution, small size and fast development times) that are considered pre-requisites for toxicity test organisms, and has previously been shown to be a sensitive component of the stream community to contaminant exposure. Prior to conducting toxicity tests with B. zschokkei, studies were performed to evaluate the effects of water hardness and food quality on the development and reproduction of this copepod. These data were then used to define optimal culture conditions. Bryocamptus zschokkei was insensitive to water hardness at <150 mg 1ˉ¹ (as CaCO3), reflecting its range of tolerance in the field and suggesting the potential for toxicity testing across a range of hardness levels. Food quality affected development and reproduction: beech leaves (Fagus sylvatica L.), conditioned for 2 weeks supported optimal overall development to adult and reproduction of B. zschokkei and were chosen for use in subsequent culturing and testing regimes. Development and reproduction assays for assessing the effects of environmental parameters on B. zschokkei were combined to produce the first full life-cycle toxicity test for a freshwater copepod. This life-cycle test was relatively quick (6 weeks at 20°C) and is highly reproducible. The effects of three reference chemicals, the trace metal zinc, the pesticide lindane, and the moulting hormone 20-hydroxyecdysone (20-HE), were measured using this toxicity test. There was no effect of 20-HE (0-269 µg 1ˉ¹) on the life cycle of B, zschokkei. Bryocamptus zschokkei was, however, relatively sensitive to zinc and lindane compared with other freshwater crustaceans although sensitivity depended on the chemical and the duration of exposure. A model of ‘equiproportional development' was used to aid interpretation of the mechanism of toxicity of lindane, which was found to act by significantly prolonging the development time to adult. Reproductive endpoints (numbers of eggs and nauplii per female) were the most sensitive measure of zinc and lindane exposure, with lowest observed effect concentrations (LOEC) of 0.48 mg Zn 1ˉ¹ and 32 fig lindane 1ˉ¹, respectively. An increase in abortion frequency, observed for these contaminants, may have potential as a biomarker of stress for this copepod. In conclusion, it is proposed that toxicity tests with B. zschokkei should be included in contaminant assessment procedures for freshwater systems as they would increase the choice and ecological relevance of current testing regimes.
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Scanlan, Clare M. "The development of algal-based toxicity testing for biocides used in marine industries." Thesis, Heriot-Watt University, 1985. http://hdl.handle.net/10399/1951.
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McKay, Gillian Claire. "Cryopreservation of hepatocyte monolayers : a potential in vitro model system for toxicity testing." Thesis, University of Strathclyde, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366885.
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Mallevre, Florian. "Bacteria nanoparticle toxicity testing : toward the use of original methods and complex matrices." Thesis, Heriot-Watt University, 2016. http://hdl.handle.net/10399/3103.
Full textAbstract:
The development and use of engineered nanoparticles (NPs) has continuously expanded over the last two decades. Despite clear beneficial aspects of NPs, their extensive use and hardly regulated dissemination has raised concern regarding their potential adverse effects. Reports on the environmental release of NPs in wastes, waters, and wastewaters have emerged as well as ecotoxicity related information to a diverse range of model microorganisms (e.g. crustaceans, worms, algae, bacteria). However, in spite of growing knowledge in nanoecotoxicology there is limited evidence to draw conclusive statements about the toxicity and fate of NPs, especially in real matrices, in part due to a lack of appropriate methodologies. In this context, this work aimed to investigate the ecotoxicity of widely used and potentially antimicrobial inorganic NPs (Ag, ZnO, CuO, TiO2) to environmentally relevant bacteria (Pseudomonas putida) in various matrices (microbiological growth medium, artificial wastewater, real crude and final wastewaters). Complementary planktonic (i.e. using a luminescent switch-off bioreporter in a microtitre plate format) and biofilm (i.e. using mono and multi-species structures in flow-cell reactors) based assays were used. In addition, the implementation of microcantilever (μCT) and surface plasmon resonance imaging (SPRi) biosensor technologies were piloted. Toxicity of NPs was discussed across approaches (when applicable) in light of their physico-chemical characterisation (using dynamic light scattering, atomic absorption spectroscopy, and ultraviolet-visible spectrophotometry) in used matrices of exposure. This work provides both practical and fundamental insights about water/wastewater related ecotoxicology of NPs using bacteria. Overall outputs highlighted the suitability of original methods for testing of NPs in or with complex (i.e. real) materials and emphasised further the possible limited impact of NPs below the mg L-1 level to bacteria (as planktonic or biofilms) in the environment, especially with ageing of NPs (as reported with the Ag NPs), or considering the potential of recovery of bacterial structures (as shown with the biofilms). In addition, the workability of SPRi for testing of NPs was reported for the first time with bacteria, offering new opportunities of further real-time and high throughput biosensor based applications in nanoecotoxicology.
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Yu, Lok Chiu. "Cellular metabolism in in vitro toxicity and toxicology studies." HKBU Institutional Repository, 2005. http://repository.hkbu.edu.hk/etd_ra/675.
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Hintzen, Emily P. Belden Jason B. "Quantifying the presence of current-use insecticides and toxicity of sediments in urban residential watersheds in central Texas." Waco, Tex. : Baylor University, 2007. http://hdl.handle.net/2104/5061.
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Li, Minghua. "The oxidation of carbon nanotubes and their environmental implications exemplified by the responses of Ceriodaphnia dubia." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 229 p, 2009. http://proquest.umi.com/pqdweb?did=1891555411&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Handy, Andrea Renee. "Acute Toxicity and Immunotoxicity Testing of Total Petroleum Hydrocarbons in Aquatic and Terrestrial Organisms." Wright State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=wright1185910580.
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Bergström, Gunnar. "Exploring the SPR methodology for monitoring of critical attributes in toxicity testing and bioproduction." Licentiate thesis, Linköpings universitet, Teknisk biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-73410.
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Analysis of biological components is central in bioprocess monitoring, process control, product quality control and cell based toxicity assaying. One of these themes that is pursued in this thesis is the use of biosensors for monitoring of molecular markers, exploiting the natural selectivity of biomolecules. Another is the use of glycoconjugates to monitor the activity of biomolecules in a flu vaccine process is studied and were the sensor is based on the concept of weak affinity giving fast response time for the sensor. A third theme is monitoring of cell cultures used for toxicity testing different protein markers is of interest. When developing biosensor surfaces for new antigens commercial preparations of antibodies are often used. In this work we have chosen to look at lactate dehydrogenase (LDH) and describe the preparation and characterisation of antibody used in biosensor surface development. The design of a sensor surface is important for the characteristics of a sensor. By binding antibodies in an oriented manner to the surface a better control of the properties of the antibodies is achieved. The demonstrated method also has the advantage of in situ purification and provides a flexible platform for antibody evaluation and sensor development. In one sentence this thesis explores the possibility of utilizing recognition elements of a biosensor surface. In particular, surface plasmon resonance (SPR) is used as the primary biosensing tool, however most findings in are relevant for other biosensors. Moreover, the thesis approaches existing bioanalytical impediments, such as purity and accessibility of the recognition elements on the sensor surface and preparation strategies to achieve this.
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Yeager, Mary Melinda. "Abiotic and biotic factors influencing the decline of native unionid mussels in the Clinch River, Virginia." Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06062008-165757/.
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Nicholls-Grzemski, Felicity April. "The effect of short-term pretreatment with peroxisome proliferators on the acute toxicity of various toxicants, including paracetamol /." Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phn6158.pdf.
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Masango, Mxolisi Goodwill. "A comparative analysis of the cytotoxicity of cyanotoxins using in vitro (cell culture) and in vivo (mouse) assays." Diss., Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-05122008-100402/.
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Pu, Yubing. "Toxicity assessment of engineered nanoparticles." Thesis, Troyes, 2017. http://www.theses.fr/2017TROY0001/document.
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L'objectif de cette thèse est d'améliorer la compréhension de la toxicité de diverses nanoparticules de synthèse (ENPs) pour l'homme et l'écosystème. Les travaux réalisés s’appuient sur la combinaison de données toxicologiques et d’un modèle environnemental - le modèle USEtox. En tant qu'élément important de l'évaluation de l'impact du cycle de vie, le facteur de caractérisation (CF) a été utilisé, dans ce travail, comme indicateur de toxicité pour l'homme et l'écosystème. Pour avoir accès aux courbes dose-réponse et à différentes données toxicologiques, des expériences in vitro ont été réalisées en exposant des neutrophiles porcins fraîchement isolés à trois types de nanoparticules de synthèse. Les modifications morphologiques, les taux de mortalité et la chimioluminescence des neutrophiles ont été évaluées. De plus, pour estimer le temps de persistance des nanoparticules de synthèse dans l'écosystème eau douce, un modèle basé sur la science des colloïdes a été développé. Il prend en compte les comportements spécifiques des nanoparticules de synthèse et inclut des recommandations sur le choix des paramètres hydrologiques régionaux. Enfin, une enquête documentaire exhaustive a été réalisée pour recueillir les données écotoxicologiques de diverses nanoparticules de synthèse. Dans le cadre du modèle USEtox, le CF toxicologique non cancérogène pour cuivre NPs et les CF écotoxicologiques pour 14 ENPs sont recommandés. Ces valeurs des CF pourraient être utiles à l'avenir pour évaluer les impacts environnementaux des produits contenant des ENPsThe objective of this thesis is to improve understandings of toxicity of various engineered nanoparticles (ENPs) to human and ecosystem. It is realized via coordinating toxicological data and a scientific consensus environmental model -- the USEtox model. As an important element in life cycle impact assessment, the characterization factor (CF) is employed as a toxicity indicator for human and ecosystem in this work. To obtain the firsthand dose-response phenomena and human toxicological data, in vitro experiments have been conducted by exposing freshly isolated porcine neutrophils to three kinds of ENPs (i.e. copper, nickel and aluminum oxide nanoparticles). The morphologies, mortality rates, and chemiluminescence, of neutrophils are observed or monitored. Additionally, to estimate the persistence time of ENPs in freshwater ecosystem, a fate model on the basis of colloid science is developed. It takes nano-specific behaviors of ENPs into account and includes recommendations of regionalized hydrological parameters. Finally, a comprehensive literature survey is accomplished to collect the ecotoxicological data of various ENPs. Under the framework of USEtox model, the non-carcinogenic human toxicological CFs for Copper NPs and the ecotoxicological CFs for 14 ENPs are recommended. These CF values could be useful in the future when evaluating the environmental impacts of products containing ENPs
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Roper, Jeannie Marie. "Sediment toxicity and bioaccumulation of toxicants in the zebra mussel, Dreissena polymorpha, at Times Beach, Buffalo, New York." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-12302008-063837/.
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Wren, Jodie Frances. "Life-cycle toxicity testing in Caenorhabditis elegans : comparative effects on traits and their mechanistic basis." Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/55648/.
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A major aim of ecotoxicology is to discover how toxicants impact populations. Often lethality is used as an endpoint in toxicity tests however this in isolation is inadequate to predict consequences for populations. The combination of life cycle toxicity testing and demographic modelling offers an opportunity to provide a solution to this problem, whilst the use of transcriptomic profiling offers the chance to understand how changes in life history are mediated at the molecular level. The nematode Caenorhabditis elegans was utilised to elucidate the effects of environmental toxicants on the life history of individuals, population growth rate, energy utilisation, and gene expression. Toxicity of four common pollutants (cadmium, fluoranthene, atrazine and aldicarb) was assessed in full life-cycle toxicity tests. The impact of each chemical on life history parameters including reproductive output/ period, time to maturity, growth and lifespan, was determined. These experiments revealed complex dose dependent responses indicating the most sensitive trait to be reproductive output. The influence of temperature and strain was investigated on cadmium toxicity indicated an increase in overall sensitivity at higher temperature and strain specific response profiles. Integration of life history data into a demographic model provided a solution to translating effects on individuals into meaningful population responses. Decreases in juvenile survival and reproduction were identified as the traits which caused the largest impacts on population growth rate. Life-cycle toxicity data was also integrated into a process-based model (DEBtox) to assess the effects of the toxicants on energy utilisation by the organisms. Finally, the mechanistic basis of observed life-history responses for the toxicant aldicarb was examined using transcriptomic profiling to identify single genes and biological and energetic pathways responsive to toxicant stress. Analysis of the molecular responses revealed novel mechanisms of toxicity.
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Berkelind, Ellinor. "In vitro bioassays for toxicity testing of wastewater - an evaulation of different sample treatment techniques." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-412525.
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Chou, Hsun-Wen. "Nanotoxicology from nano titanium dioxide particle size effect on Ceriodaphnia dubia to death mechanism /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 77 p, 2008. http://proquest.umi.com/pqdweb?did=1597633671&sid=14&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Bakand, Shahnaz Safety Science Faculty of Science UNSW. "Development of in vitro methods for toxicity assessment of workplace air contaminants." Awarded by:University of New South Wales. School of Safety Science, 2006. http://handle.unsw.edu.au/1959.4/24246.
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Exposure to air contaminants is significantly associated with both short-term and long-term health effects. However, the precise mechanisms that derive such effects are not always understood. While an extensive background database from in vivo toxicological studies have been developed, most toxicity data is from oral and dermal chemical exposures rather than inhalation exposure. There is a need to explore new alternative approaches to provide toxicity information particularly on this technically demanding area. This research explores the potential of in vitro methods for toxicity assessment of workplace air contaminants. A tiered approach for in vitro toxicity testing of workplace contaminants was designed in which appropriate air sampling and exposure techniques were developed. A diversified battery of in vitro assays including the MTS (tetrazolium salt, Promega), NRU (neutral red uptake, Sigma) and ATP (adenosine triphosphate, Promega) and a multiple human cell system including: A549- lung derived cells; HepG2-liver derived cells, and skin fibroblasts were used. Primarily the application and merits of in vitro methods for prediction of toxicity of selected workplace contaminants including Ammonium hydroxide, Cadmium chloride, Cobalt chloride, Formaldehyde, Glutaraldehyde, Manganese chloride, Mercuric chloride, Sodium dichromate, Sulphureous acid and Zinc chloride was confirmed. To study the toxicity of airborne contaminants an indirect exposure method was established using air sampling techniques followed by static and dynamic direct exposure methods by culturing cells on porous membranes to reveal representative data relating to human airborne exposures. The static method enabled the measurement of an airborne IC50 (50% inhibitory concentration) value for selected volatile organic compounds (VOCs) including: Xylene (IC50 = 5,350-8,200 ppm) and Toluene (IC50 = 10,500- 16,600 ppm) after 1 hr exposure. By implementing the dynamic method, airborne IC50 values were calculated for gaseous contaminants including: NO2 (IC50 = 11 ?? 3.54 ppm; NRU), SO2 (IC50 = 48 ?? 2.83 ppm; ATP) and NH3 (IC50 = 199 ?? 1.41 ppm; MTS). A higher sensitivity of in vitro methods was observed compared to in vivo published data. A range of in vitro bioassays in conjunction with exposure techniques developed in this thesis may provide an advanced technology for a comprehensive risk assessment of workplace air contaminants.
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Figueiredo, Joana Rita Monteiro. "Toxicity of novel anti-fouling nanomaterials in Marine organismsv." Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22019.
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Mestrado em Ecologia AplicadaBiofouling is an ecological succession of fouling communities in submerged surfaces that has extensive ecological, environmental and economic impacts worldwide when developed over man-made structures. In order to minimize this problem, biocides with anti-fouling properties are commonly used in protective coatings of submerged structures. Some decades ago, organotin compounds were used as effective anti-fouling agents, however they were completely banned in 2008 due to the toxic and biomagnification effects. As a consequence, a new generation of biocides were developed with lower toxicity and persistence in the environment when compared to organotin compounds. Recently, one of these biocides (DCOIT) was encapsulated in an engineered nanomaterial (silica mesoporous nanocapsules, SiNC-DCOIT) in order to prevent the interaction of biocides with coatings’ ingredients and control their leaching rate during the early lifetime of conventional paints, with environmental and economic benefits. The present study aimed to assess the toxicity of SiNC-DCOIT and a modified version of the engineered nanomaterial including two biocides, the SiNC-DCOIT coated with silver, to marine species and compare its toxicity with the free counterparts (empty SiNC, DCOIT and Ag). Ecotoxicity tests were carried out with eleven marine species, including bacteria (Vibrio fischeri), microalgae (Isochrysis galbana, Nannochloropsis gaditana, Phaeodactylum tricornutum), rotifers (Brachionus plicatilis), bivalves (Cerastoderma edule, Mytilus galloprovincialis), polychaetes (Hediste diversicolor), crustaceans (Artemia salina, Palaemon varians) and echinoderms (Paracentrotus lividus), following standard tests (with some adaptions in some cases). Acute or short-term chronic endpoints were used upon each species and adopted test. Globally, values of L/E/IC50 for SiNC-DCOIT, SiNC-Ag and SiNC-DCOIT-Ag were higher than the estimated values for DCOIT and silver (dissolved in solution), except for some target groups involved in the early fouling stages, proving that these alternative agents are more environmentally-friendly comparatively to free biocides. The obtained L/E/IC50 and NOEC values from the tested compounds were then used to create species sensitivity distributions together with data from literature. The HC5 and PNEC values derivated from these curves showed that the hazard of DCOIT and silver is reduced when encapsulated, highlighting these novel nanomaterials as a promising anti-fouling solution.
A bioincrustação é uma sucessão ecológica de comunidades incrustantes em superfícies submersas que tem extensos impactos ecológicos, ambientais e económicos em todo o mundo quando desenvolvida em estruturas artificiais. Para minimizar esse problema, os biocidas com propriedades anti-incrustantes são comummente utilizados em revestimentos protetores de estruturas submersas. Há algumas décadas atrás, os compostos organoestânicos eram amplamente utilizados como agentes anti-incrustantes eficazes, porém foram definitivamente banidos em 2008 devido a efeitos tóxicos e de biomagnificação reportados. Como consequência, foi desenvolvida uma nova geração de biocidas com menor toxicidade e persistência no meio ambiente em comparação com os compostos organoestânicos. Recentemente, um desses biocidas (DCOIT) foi encapsulado num nanomaterial manufaturado (nanocápsulas de sílica mesoporosas, SiNC-DCOIT), a fim de evitar a interação dos biocidas com os ingredientes dos revestimentos e controlar a sua taxa de libertação durante o início de vida das tintas convencionais, com benefícios ambientais e económicos. O presente estudo teve como objetivo avaliar os efeitos em diversas espécies marinhas do nanomaterial SiNC-DCOIT e de uma versão modificada deste, contendo dois biocidas (SiNC-DCOIT revestido com prata), e comparar a sua toxicidade com os componentes destes nanomateriais (SiNC vazias, DCOIT e Ag). Os testes de ecotoxicidade foram realizados com onze espécies marinhas, incluindo bactérias (Vibrio fischeri), microalgas (Isochrysis galbana, Nannochloropsis gaditana, Phaeodactylum tricornutum), rotíferos (Brachionus plicatilis), bivalves (Cerastoderma edule, Mytilus galloprovincialis), poliquetas (Hediste diversicolor), crustáceos (Artemia salina, Palaemon varians) e equinodermes (Paracentrotus lividus), seguindo testes padrão (com algumas adaptações em alguns casos) ou com protocolos bem definidos. Foram determinados parâmetros agudos ou crónicos de curta duração dependendo da espécie testada e do teste adotado. Globalmente, os valores de L/E/IC50 para SiNC-DCOIT, SiNC-Ag e SiNC-DCOIT-Ag foram superiores aos valores estimados para DCOIT e prata (dissolvidos em solução), com exceção de alguns grupos alvo envolvidos nos primeiros estádios de incrustação, provando assim que estes são agentes alternativos mais amigos do ambiente comparativamente aos biocidas livres. Os valores obtidos de L/E/IC50 e NOEC para os compostos testados foram depois utilizados para derivar curvas de distribuições de sensibilidade de espécies, juntamente com dados da literatura. Os valores HC5 e PNEC derivados dessas curvas mostraram que o perigo do DCOIT e da prata diminui quando encapsulados, destacando que estes nanomateriais inovadores parecem ser uma solução anti-incrustante promissora.
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