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1
Smith, Maree J. "Biodegradation of the cyanotoxin cylindrospermopsin /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18474.pdf.
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Arnette, Verna J. "Cyanotoxin Removal in Drinking Water Treatment Processes." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1258475751.
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Catlin, Diane M. "DNA Aptamer Confirmation and Utilization for the Cyanotoxin, Cylindrospermopsin." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2552.
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Cyanotoxins are posing an increasing threat to the health of humans and wildlife. Cylindrospermopsin is a cyanotoxin that occurs in warm climates and is harmful when ingested. The toxic effects of CYN can affect multiple organ systems. The effects, coupled with the evidence of a mass contamination of a water supply in Australia, prove that CYN needs to be investigated further.
Aptamers have become a desirable method for detection of CYN as a result of an aptamer’s high specificity and the ability to scale up experiments. Aptamers have been designed to bind with a variety of targets, including cyanotoxins. An aptamer for CYN was identified by Elshafey et al.
This study aims to confirm the binding of the aptamer to CYN and the selectivity of the aptamer using fluorescent biosensing and circular dichroism. Aptamer affinity capture was used to investigate the possibility of a real world application of the aptamer.
4
Smith, Francine Mary Jorna. "Investigating Cyanotoxin Production by Benthic Freshwater Cyanobacteria in New Zealand." Thesis, University of Canterbury. Chemistry, 2012. http://hdl.handle.net/10092/6932.
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Cyanobacteria can form nuisance proliferations and produce large concentrations of toxins that pose a health hazard. This thesis investigates cyanotoxin production by New Zealand benthic cyanobacteria. Cyanobacteria were sampled from lakes, reservoirs, streams, and rivers. Thirty-five strains were isolated into culture and screened for genes involved in the biosynthesis of common cyanotoxins. Positive results were confirmed and cyanotoxin concentrations quantified using analytical chemistry techniques.
Genes involved in anatoxin a/homoanatoxin a biosynthesis were detected in nine out of ten Phormidium cf. uncinatum strains isolated from a single mat. Anatoxin a was confirmed in these strains by LC–MS/MS at concentrations from 0.3 to 6.4 mg kg⁻¹. One strain also produced homoanatoxin-a. Anatoxin-a variation between strains may explain the wide range in anatoxin a concentrations previously observed in New Zealand.
The sxtA gene involved in saxitoxin biosynthesis was identified in Scytonema cf. crispum strains. Saxitoxin was confirmed in strains and environmental samples by Jellett PSP Rapid Test and HPLC–FD. Gonyautoxins, neosaxitoxin, and decarbamoyl derivatives were also detected. This study is the first identification of these compounds in Scytonema and in New Zealand cyanobacterial strains. These strains were isolated from recreational and pre-treatment drinking water reservoirs, highlighting the risk benthic cyanobacteria pose to human and animal health.
Experiments were undertaken using cultures of Phormidium and Scytonema to determine how growth influences cyanotoxin production. The effects of iron and copper stress on P. autumnale were also investigated. High iron concentrations disrupted attachment mechanisms. Iron and copper had a significant effect on growth, without significantly affecting anatoxin a production. However, the maximum anatoxin a quota was consistently observed during early exponential growth. Scytonema cf. crispum produced higher saxitoxin quota throughout exponential growth than during the stationary phase. Both the Phormidium and Scytonema growth experiments indicate that high toxin quota can be expected early in benthic mat development, making early detection of these proliferations important.
5
Jiang, Xuewen. "Sustainable Methods for Cyanotoxin Treatment and Discovery of the Cyanophage." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492098348720028.
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Buchholz, Seth D. "Rapid Cyanotoxin Detection Technology in Routine Monitoring and Citizen Science Groups." Bowling Green State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1616074976068045.
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Chandu, Vijith Cholakkal Parambil. "Investigation of novel methods to remove the cyanotoxin, Cylindrospermopsin, from drinking water." Thesis, Robert Gordon University, 2013. http://hdl.handle.net/10059/852.
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The widespread distribution of cyanobacteria and their toxic effects on humans has become a major concern for researchers. Cyanobacteria are a group of oxygenic phototrophic bacteria that exhibit an enormous diversity in shapes and arrangements and occupy widespread habitats that include brackish, marine and fresh water. The major concern among these organisms is not so much the cyanobacteria themselves but their toxin production. Under suitable circumstances, cyanobacteria can reach high biomass levels and form toxic algal blooms. These toxins, known as cyanotoxins, are produced as secondary metabolites by several cyanobacterial species. Cyanotoxins affect not only aquatic ecosystems but also impact on human health. The current work focuses on the cyanotoxin cylindrospermopsin that was originally known to be produced by the cyanobacterium species Cylindrospermopsis raciborskii but has since been identified in a number of other cyanobacterial species. Cylindrospermopsin is hepatotoxic and acts as a strong inhibitor of protein synthesis. The increasing occurrence of toxic cyanobacterial blooms is of major concern, particularly within drinking water supply systems. Therefore, the investigation of more effective water treatment technologies is of great importance in order to ensure the removal of these potent toxins. There are many techniques that have been used so far, but the need to use an effective and efficient method to remove the toxicity is paramount. Removal of the toxin by the use of microbial degradation has been evaluated. Experiments with different strains of bacterial isolates showed positive signs in the removal of toxin by Biolog MT2 assay. In addition to that shake flask culture experiments were carried out and did not show any significant removal of the toxin. Studies with natural water sources showed some pronounced effect on the removal of CYN. The use of TiO2 photocatalysis as another potential water treatment strategy was also evaluated. Current study successfully demonstrated the potential degradation of purified cylindrospermopsin using the titanium dioxide (TiO2) photocatalysis treatment method. TiO2 photocatalysis was performed by using a powder form (Degussa P25) catalyst effectively removing the toxin; however, the powder is difficult to remove from the treated water. TiO2 pellets (Hombikat K01/C) were found to be slower in degradation although they allowed for an easier adaption to a continuous treatment system. As an alternative Photospheres™ (buoyant glass beads coated in TiO2) was evaluated and showed the same efficacy as that of Degussa P 25. Studies were extended to investigate the application of UV-LEDs in the photocatalysis reaction to show better efficiency.
8
Gagnon, Alexis. "The Cyanotoxin Anatoxin-a: Factors Leading to its Production and Fate in Freshwaters." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20679.
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Anatoxin-a (ANTX) is a neurotoxin produced by several freshwater cyanobacteria and has
been implicated in the death of livestock and domestic animals from consumption of tainted
surface waters. ANTX is unstable under normal conditions and is somewhat problematic to
extract and study. Accelerated solvent extraction (ASE) combined with liquid
chromatography-mass spectrometry (LC/MS) was used to develop an efficient extraction and
analytical method for both ANTX and the more commonly encountered hepatotoxic
microcystins produced by cyanobacteria. The effects of nitrogen supply on the cellular
production and release of ANTX was investigated in Aphanizomenon issatschenkoi
(Ussaczew) Proschkina-Lavrenko (Nostocales). In contrast to the predictions of the carbonnutrient
balance hypothesis, the maximum production was observed under moderate N stress.
In addition, steady state fugacity-based models were employed to investigate ANTX’s
distribution and fate in freshwater ecosytems. ANTX was not found to be very persistent in
aquatic ecosystems and did not appear to bioaccumulate in fish, at least not from the
dissolved phase.
9
Vogiazi, Vasileia. "Developing Electrochemical Aptamer-based Biosensors for Quantitative Determination of Cyanotoxins in Water." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613751183300163.
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Varner, Mia. "Using High Frequency Monitoring of Environmental Factors to Predict Cyanotoxin Concentrations in a Multi-use, Inland Reservoir." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1525171037880198.
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McCollough, Bianca. "Toxic algae and other marine biota: detection, mitigation, prevention and effects on the food industry." Kansas State University, 2016. http://hdl.handle.net/2097/32490.
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Master of ScienceFood Science Institute
Curtis Kastner
Harmful Algal Blooms (HABs) including Cyanobacteria and other toxic marine biota are responsible for similar harmful effects on human health, food safety, ecosystem maintenance, economic losses and liability issues for aquaculture farms as well as the food industry. Detection, monitoring and mitigation are all key factors in decreasing the deleterious effects of these toxic algal blooms. Harmful algal blooms can manifest toxic effects on a number of facets of animal physiology, elicit noxious taste and odor events and cause mass fish as well as animal kills. Such blooms can adversely impact the perception of the efficacy and safety of the food industry, water utilities, the quality of aquaculture and land farming products, as well as cause ripple effects experienced by coastal communities. HABs can adversely impact coastal areas and other areas reliant on local aquatic ecosystems through the loss of revenues experienced by local restaurants, food manufacturers as well as seafood harvesting/processing plants; loss of tourism revenue, decreased property values and a fundamental shift in the lives of those that are reliant upon those industries for their quality of life. This paper discusses Cyanobacteria, macroalgae, HABs, Cyanobacteria toxins, mitigation of HAB populations and their products as well as the ramifications this burgeoning threat to aquatic/ landlocked communities including challenges these toxic algae pose to the field of food science and the economy.
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Velkme, Erik. "A novel method for antisense oligonucleotide gene expression manipulation in toxigenic cyanobacterial species, Microcystis aeruginosa." OpenSIUC, 2020. https://opensiuc.lib.siu.edu/theses/2781.
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Algal blooms caused by toxigenic cyanobacterial species are an increasing economic burden globally, as high anthropogenic inputs of nitrogen and phosphorous, coupled with rising levels of atmospheric CO2, promote eutrophication and enhance bloom proliferation. Of the freshwater bloom forming species, Microcystis aeruginosa has garnered the most attention due to the production of toxic secondary metabolites known as microcystins. These cyclic peptides are potent eukaryotic protein phosphatase 1 and 2A inhibitors, and can induce hepatic damage if concentration levels reach above the World Health Organization level of 1 µg/L. Current mitigation strategies of water column disruption or by use of broad acting chemicals, are limited in their range and may cause unwanted off target effects to the surrounding biota. Antisense oligonucleotides are short single-stranded DNA polymers that hybridize with transcribed mRNA, and suppress translation of protein products through steric hindrance of ribosomes, or by RNAse H degradation of the DNA/RNA bound complex. While antisense oligonucleotide applications have proven successful in the pharmaceutical industry, their potential remains largely unexplored in environmental contexts. For this reason, we investigated the knockdown of microcystin synthetase gene cluster mcyE in M. aeruginosa. We found that ionic charge neutralization coupled with heat shock were effective chemical competence based methods for delivery, mcyE transcript abundance in cells treated with phosphodiester linked antisense oligonucleotides significantly decreased in RT-qPCR analysis, and production of intracellular microcystin significantly decreased over a 24 hour period (-1.9 fg/cell). This work demonstrates a novel proof of concept for the potential use of exogenous antisense oligonucleotides to target M. aeruginosa in harmful algal bloom occurrences.
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Halvorson, Rebecca Ann. "Raman Spectroscopy for Monitoring of Microcystins in Water." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/76924.
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Cyanobacterial blooms are of great concern to the drinking water treatment industry due to their capacity to produce microcystins and other cyanotoxins that are deadly to humans, livestock, pets, and aquatic life at low doses. Unfortunately, the strategies currently employed for cyanotoxin detection involve laborious analyses requiring significant expertise or bioassay kits that are subject to numerous false positives and negatives. These methods are incapable of providing rapid, inexpensive, and robust information to differentiate between the >80 cyanotoxin variants potentially present in an aqueous sample.
The use of Raman spectroscopy for identification and quantification of the ubiquitous cyanotoxin microcystin-LR (MC-LR) was examined. Raman spectra readily reflect minute changes in molecular structure, spectra can be collected through water or glass, portable Raman spectrometers are increasingly available, and through surface enhanced Raman spectroscopy (SERS) it is possible to achieve femto or picomolar detection limits for a variety of target species. Drop coating deposition Raman (DCDR) was successfully implemented for quantitation of 2-100 ng of MC-LR deposited in 2 ?L of aqueous sample, even without the use of a specifically designed DCDR substrate or Raman signal enhancements. Reproducible MC-LR Raman spectra were observed for both fresh and aged DCDR samples, and the MC-LR Raman spectrum remained identifiable through a matrix of >80% DOM by mass. DCDR methods show tremendous potential for the rapid, simple, and economical detection of cyanotoxins in environmental matricies at environmentally relevant concentrations.Master of Science
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Lee, Seungjun. "Microbiome and Virome Dynamics in Lakes Impacted by Cyanobacterial Harmful Algal Blooms and the Fate of Cyanobacteria and Cyanotoxin in Crops and Soil." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1513690700478319.
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Garcia, Ana Cristina de Almeida. "Aplicação de fotoeletrooxidação na degradação de Microcystis aeruginosa e da toxina microcistina." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/96501.
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A crescente eutrofização dos ambientes aquáticos é consequência das atividades humanas que desequilibram os ecossistemas. A descarga de esgotos urbanos, a utilização de adubos químicos, os efluentes das agroindústrias e dos diversos setores industriais promovem a entrada de quantidades significativas de nutrientes e matéria orgânica em corpos d´água, favorecendo o aumento das florações de algas, entre elas as cianobactérias. O excesso de matéria orgânica e os despejos de efluentes agroindustriais nos mananciais hídricos representam os principais fatores do excesso de floração das cianobactérias, destacando-se a Microcystis aeruginosa e da sua cianotoxina microcistina. Nesta tese foi aplicado o Processo Oxidativo Avançado (POA) de Fotoeletroxidação (FEO) para a degradação de Microcystis aeruginosa e da cianotoxina microcistina. Investigou-se a otimização de parâmetros como tempo de tratamento e intensidade de corrente elétrica aplicada. Os resultados obtidos nas condições aplicadas demonstram valores de 99% para a degradação de Microcystis aeruginosa e cianotoxina Microcistina com o tempo de 10min e densidade de corrente de 2mA.cm-2. Os testes de toxicidade aguda com ajuste de pH de 6,3 para 7,3 não apresentaram toxidade para a espécie teste Pimephales promelas.The increasing eutrophication of aquatic environments is a consequence of human activities that disrupt ecosystems. The discharge of urban sewage, the use of chemical fertilizers, effluents from agro-industries and other industrial sectors promote the input of significant amounts of nutrients and organic matter in water, favoring increased blooms of algae, including cyanobacteria. Excessive organic matter and the discharge of agroindustrial effluents in the water bodies, represent the main factors for the excessive bloom of cyanobacteria, especially Microcystis aeruginosa and microcystin cianotoxin. In this study, an Advanced Oxidation Process named photoelectrooxidation, was used to the degradation of Microcystis aeruginosa and cianotoxin microcystin. The optimization of parameters such as, treatment time and intensity of electrical current applied in the process of PEO were evaluated. The results achieved under the conditions applied, show 99% of degradation with experimental times at 10 minutes and a current density of 2mA.cm-2. The acute toxicity tests, with pH adjustment from 6.3 to 7.3, did not show toxicity to the species Pimephales promelas.
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Tan, Vanessa. "Identification of biomarkers for MND, and understanding the potential role of the cyanotoxin BMAA in neurodegeneration Involvement of Quinolinic Acid in the Neuropathogenesis of amyotrophic lateral sclerosis Detection of the Cyanotoxins L-BMAA Uptake and Accumulation in Primary Neurons and Astrocytes." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS590.
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La Sclérose Latérale Amyotrophique (SLA) est une maladie neurodégénérative dévastatrice dont les causes sont inconnues et pour laquelle il n’existe aucun traitement ni marqueur spécifique. Dans ce contexte, nous avons étudié le rôle de la voie métabolique des kynurénines impliquée dans la production de métabolites neuroactifs qui peuvent être immunomodulateurs, neuroprotecteurs ou à l’inverse neurotoxiques. Dans une étude longitudinale du sérum de 66 patients atteints de SLA, nous avons évalué le profil de 10 métabolites de la voie des kynurénines par chromatographie HPLC et spectrographie GC/MS. Nous avons mis en évidence un profil métabolique, spécifique de la progression de la SLA, qui pourrait être utilisé comme biomarqueur pour suivre l’évolution de la maladie. En collaboration avec la clinique de la SLA de l’Université Macquarie de Sydney, nous avons constitué une banque d’échantillons de patients atteints de SLA et d’autres maladies neurodégénératives (Parkinson, Alzheimer) ce qui permettra de rechercher à plus grande échelle les facteurs responsables de l’étiologie et du décours de la SLA. Dans une seconde partie, nous avons évalué le potentiel neurotoxique de la (BMAA), une cyanotoxine dont la présence dans l’environnement est corrélée avec une incidence accrue de la SLA. A l’aide de modèles cellulaires permettant de modéliser des voies neuro-anatomiques in vitro. Nous avons démontré que la BMAA provoque une déstructuration des réseaux de neurones et mis en évidence la capacité de cette biotoxine, qui s’apparente à un acide aminé, de se propager de cellule à cellule et donc potentiellement de se disperser dans le système nerveux centralMotor Neuron Disease (MND) or Amyotrophic Lateral Sclerosis (ALS) is a devastating neurological disease with no biological diagnostic markers, no effective treatment, and no cure. We investigate the immune related Kynurenine Pathway (KP) for a role in ALS. The production of neuroactive metabolites during the KP indicate that there is an overlap with the mechanisms of ALS, particularly with the neurotoxin quinolinic acid. Subsequently, we investigate the KP metabolome, analysing 10 metabolites using biochemical analyses including High Performance Liquid Chromatography and Gas Chromatography/Mass Spectrometry. Using serum from a longitudinal cohort of 66 ALS patients, we establish a potential for KP metabolomics to be used a biomarker for ALS. To increase specificity and reliability of these results, in collaboration with Macquarie University Neurology, we established a Neurodegenerative Diseases Biobank to collect patient biological samples. These samples would facilitate future investigations into the mechanisms, genetics, biomarkers, and to detect the presence of toxic compounds such as metals, or β-methylamino-L-alanine (BMAA). We describe the establishment of the biobank as a case study for future references. BMAA is known to be neurotoxic, and we investigate its role ALS. We reveal its role in promoting axonal degeneration and neuronal death, and show for the first time, its ability to spread transcellularly
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Hereman, Talita Caroline [UNESP]. "Efeitos do extrato bruto e da microcistina-LR em Lactuca sativa L. (Asteraceae)." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/87875.
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Plantas cultivadas podem ser contaminadas com cianotoxinas através de irrigação com água contendo cianobactérias tóxicas. Uma espécie freqüentemente encontrada nos corpos d’agua é Microcystis aeruginosa, produtora da microcistina (MC), uma toxina hepatotóxica. Frente a esta possibilidade, nosso objetivo foi investigar os efeitos de extrato bruto de uma linhagem produtora de microcistina (BCCUSP232) e outra não produtora (BCCUSP03) em bioensaio de germinação de sementes e crescimento da hortaliça alface e a possibilidade de bioacumulação da cianotoxina nos tecidos foliares. Sementes germinadas em papel de filtro foram expostas a concentrações entre 0,5 a 100 μg.L-1 de MC-LR durante sete dias, enquanto as plantas cultivadas em vasos contendo substrato comercial para hortaliça foram irrigadas com 100ml de solução aquosa contendo 0,5 a 10 μg.L-1 de MC-LR durante 15 dias ao final do ciclo da cultura. Valores de massa seca correspondentes foram empregados para o tratamento com extrato bruto sem microcistina, além de controle com água. Os efeitos nocivos da MC-LR puderam ser observados no desenvolvimento das plântulas expostas a 75 e 100 μg.L-1, concentrações que induziram uma maior ocorrência de plântulas anormais devido ao aparecimento de necrose na radícula e encurtamento deste órgão nas plântulas normais, como também redução no teor de clorofila e aumento na atividade da enzima antioxidante peroxidase. Para as plantas adultas, a exposição às diferentes concentrações de MC-LR não interferiram no teor de clorofila e na atividade da peroxidase. Contudo, ambos os extratos (com e sem MC-LR) interferiram igualmente na permeabilidade seletiva da membrana plasmática das folhas da planta adulta, mesmo em baixa concentração, podendo assim deixá-la mais suscetível a estresses abióticos e bióticos. Embora as plantas se apresentassem saudáveis...
Crop plants may become contaminated with cyanotoxins during irrigation with water containing toxic cyanobacteria, such as Microcystis aeruginosa, which produces the hepatoxin microcystin (MC). The aim of the present study was to investigate the effects of a crude extract from a microcystin-producing strain (BCCUSP232) and non-microcystin-producing strain (BCCUSP03) on germination and growth bioassays of lettuce and assess the possibility of the bioaccumulation of this cyanotoxin in leaf tissue. Seeds germinated on filter paper were exposed to concentrations of 0.5 to 100 μg.L-1 of MC-LR for seven days, while plants grown in pots containing a commercial substrate were irrigated with 100mL of an aqueous solution containing 0.5 to 10 μg.L-1 of MC-LR for 15 days at the end of the culture cycle. The corresponding dry weight values were used for treatment with the crude extract without microcystin. Control plants received only water. The harmful effects of MC-LR were observed during the development of seedlings exposed to 75 and 100 μg.L-1, with a higher incidence of abnormal seedlings due to the onset of root necrosis as well as a shortening of roots in normal seedlings, a reduction in chlorophyll content and an increase in the activity of the antioxidant enzyme peroxidase. In adult plants, exposure to different concentrations of MC-LR did not affect the chlorophyll content or peroxidase activity. However, even at low concentrations, both extracts (with and without MC-LR) equally affected the selective permeability of the plasma membrane in leaves, which could make the plants more susceptible to biotic and abiotic stresses. Although the plants looked healthy and similar to the controls, there was an accumulation of microcystin in the leaves at concentrations of 7.2 μg.kg-1 and 167.1 μg.kg-1 when... (Complete abstract click electronic access below)
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Hereman, Talita Caroline. "Efeitos do extrato bruto e da microcistina-LR em Lactuca sativa L. (Asteraceae) /." Rio Claro : [s.n.], 2010. http://hdl.handle.net/11449/87875.
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Orientador: Maria do Carmo Bittencourt de OliveiraBanca: Massanori Takaki
Banca: Sergio Florentino Pascolatti
Resumo: Plantas cultivadas podem ser contaminadas com cianotoxinas através de irrigação com água contendo cianobactérias tóxicas. Uma espécie freqüentemente encontrada nos corpos d'agua é Microcystis aeruginosa, produtora da microcistina (MC), uma toxina hepatotóxica. Frente a esta possibilidade, nosso objetivo foi investigar os efeitos de extrato bruto de uma linhagem produtora de microcistina (BCCUSP232) e outra não produtora (BCCUSP03) em bioensaio de germinação de sementes e crescimento da hortaliça alface e a possibilidade de bioacumulação da cianotoxina nos tecidos foliares. Sementes germinadas em papel de filtro foram expostas a concentrações entre 0,5 a 100 μg.L-1 de MC-LR durante sete dias, enquanto as plantas cultivadas em vasos contendo substrato comercial para hortaliça foram irrigadas com 100ml de solução aquosa contendo 0,5 a 10 μg.L-1 de MC-LR durante 15 dias ao final do ciclo da cultura. Valores de massa seca correspondentes foram empregados para o tratamento com extrato bruto sem microcistina, além de controle com água. Os efeitos nocivos da MC-LR puderam ser observados no desenvolvimento das plântulas expostas a 75 e 100 μg.L-1, concentrações que induziram uma maior ocorrência de plântulas anormais devido ao aparecimento de necrose na radícula e encurtamento deste órgão nas plântulas normais, como também redução no teor de clorofila e aumento na atividade da enzima antioxidante peroxidase. Para as plantas adultas, a exposição às diferentes concentrações de MC-LR não interferiram no teor de clorofila e na atividade da peroxidase. Contudo, ambos os extratos (com e sem MC-LR) interferiram igualmente na permeabilidade seletiva da membrana plasmática das folhas da planta adulta, mesmo em baixa concentração, podendo assim deixá-la mais suscetível a estresses abióticos e bióticos. Embora as plantas se apresentassem saudáveis... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Crop plants may become contaminated with cyanotoxins during irrigation with water containing toxic cyanobacteria, such as Microcystis aeruginosa, which produces the hepatoxin microcystin (MC). The aim of the present study was to investigate the effects of a crude extract from a microcystin-producing strain (BCCUSP232) and non-microcystin-producing strain (BCCUSP03) on germination and growth bioassays of lettuce and assess the possibility of the bioaccumulation of this cyanotoxin in leaf tissue. Seeds germinated on filter paper were exposed to concentrations of 0.5 to 100 μg.L-1 of MC-LR for seven days, while plants grown in pots containing a commercial substrate were irrigated with 100mL of an aqueous solution containing 0.5 to 10 μg.L-1 of MC-LR for 15 days at the end of the culture cycle. The corresponding dry weight values were used for treatment with the crude extract without microcystin. Control plants received only water. The harmful effects of MC-LR were observed during the development of seedlings exposed to 75 and 100 μg.L-1, with a higher incidence of abnormal seedlings due to the onset of root necrosis as well as a shortening of roots in normal seedlings, a reduction in chlorophyll content and an increase in the activity of the antioxidant enzyme peroxidase. In adult plants, exposure to different concentrations of MC-LR did not affect the chlorophyll content or peroxidase activity. However, even at low concentrations, both extracts (with and without MC-LR) equally affected the selective permeability of the plasma membrane in leaves, which could make the plants more susceptible to biotic and abiotic stresses. Although the plants looked healthy and similar to the controls, there was an accumulation of microcystin in the leaves at concentrations of 7.2 μg.kg-1 and 167.1 μg.kg-1 when... (Complete abstract click electronic access below)
Mestre
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Bertani, Paul. "Advancing Healthcare: A 3D Nanoscale Cell Electroporation Platform and AlGaN/GaN Biosensors for Cyanobacterial Toxin Detection." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu159828807909402.
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Davies, Warren Raymond, and warren davies@optusnet com au. "Effects of the Cyanobacterium Nodularia spumigena on Selected Estuarine Fauna." RMIT University. Applied Sciences, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080415.164533.
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Nodularia spumigena is an estuarine cyanobacteria that produces the toxin nodularin. This toxic cyanobacteria is known to have caused death to domestic and wild animals and is recognised as dangerous to human health. N. spumigena causes harmful algal blooms in many parts of the world including Australia. The toxic solutes of N. spumigena are potentially dangerous when contact is made to contaminated water bodies or is ingested by primary consumers. In Australia blooms of N. spumigena are common in the Gippsland Lakes in South-eastern Victoria and cause socio - economic hardships to the local communities. This PhD investigates the toxic effects of N. spumigena and its solutes to a range of aquatic life. A method known as SPME - HPLC showed promise in environmental monitoring of N. spumigena toxins by measuring nodularin from water samples. Other research presented study into the lethal and sublethal effects of on an extract from N. spumigena to aquatic fauna. Resu lts showed the N. spumigena extract was not lethal to many aquatic fauna although zooplankton from the Gippsland Lakes showed mortality at environmental relevant levels. Biochemical studies focusing on animal detoxification and antioxidation enzymes and DNA integrity showed sublethal effects to the N. spumigena extract. Results presented in this thesis show that an extract of N. spumigena elicited detoxification and antioxidation responses in animals tested. Furthermore, the use of the COMET assay showed increased damage to DNA of animals tested. Results also showed that different organs in animals tested responded differently to the aqueous extract, suggesting mode of uptake maybe important in toxicosis. Further, feeding studies with N. spumigena help elucidate mode of uptake using enzyme response biomarkers. The overall results of this research provided an assessment of the toxic affects of N. spumigena on aquatic fauna with special reference to the Gippsland Lakes, Victoria, Australia.
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Sjölund, Johanna. "Hur hanteras algblomning i dricksvattentäkt – en undersökning av algblomning i Bondsjön, Härnösands kommun, och förslag till åtgärder." Thesis, Sveriges Lantbruksuniversitet, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-379737.
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Algal blooms are a common phenomenon in lakes and seas in and around Sweden and poses a problem when found in a drinking water source. Some cyanobacteria can produce toxins which can be with a health problem. To get a safe drinking water it is necessary to be able to remove the toxins from the incoming water. This report has gathered information on cyanobacteria, cyanotoxins and conditions in the water source. Further investigation in two water sources, Bondsjön and Långsjön in Härnösand, have been made as well as a literature review regarding water treatment methods that are effective against cyanotoxins. The results from the lake investigation showed that there was almost no cyanobacteria present in the water in August 2018. Temperature- and water transparency analysis showed that the position of the intake of water to the water treatment plant is placed at a depth that may favour growth of cyanobacteria. A relocation of the intake would probably get a better quality of water regarding risk of cyanobacteria content in to the water treatment plant. The water treatment methods that would be recommended to remove cyanotoxins from the incoming water is pulverised activated carbon (PAC), granular activated carbon (GAC) and membrane filters in the form of nanofilters (NF). PAC is recommended for sporadic use, only when there is cyanotoxins in the water which will require a high control of the incoming water. GAC is recommended as a constant removal technique which will not require the extra control of the incoming water, however it is more sensitive for a high concentration of DOC in the water. NF is also recommended as a constant removal technique and which cross-flow technique is implemented to avoid accumulation of material on the filter surface.
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Alves, Marina Gumiere. "Degradação da microcistina-XR por bactérias isoladas de sistema de abastecimento público de água." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11138/tde-24112011-160040/.
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Microcistinas são potentes hepatotoxinas e promotoras de tumores encontradas em águas doces que causam riscos à saúde pública e, portanto, representam um sério problema para as estações de tratamento de água. O gênero de cianobactéria Microcystis é o mais conhecido produtor dessas toxinas e também o mais comumente encontrado formando florações em reservatórios de água usados para abastecimento público. Entretanto, algumas bactérias são capazes de utilizar essas toxinas como fonte de carbono o que pode contribuir para a sua remoção da água. Neste estudo foi avaliado o potencial de degradação da microcistina-XR (MCYST-XR) por bactérias heterotróficas isoladas de um sistema de abastecimento público de água da cidade de Piracicaba-SP. A cianotoxina MCYST-XR avaliada foi isolada da linhagem Microcystis aeruginosa NPLJ-4 e purificada. Culturas puras de 35 bactérias isoladas do sistema de abastecimento de água foram testadas. Para isso, cada bactéria foi inoculada em meio mínimo de sais contendo 60 g mL-1 de MCYST-XR purificada e após 144 horas a degradação da toxina foi avaliada por análise em LC-MS/MS. Os picos indicando a massa da microcistina-XR (m/z 1037) não foram detectados no meio de cultura de seis bactérias, as quais foram identificadas pelo sequenciamento quase completo do gene de RNAr 16S como pertencentes aos gêneros Pseudomonas sp., Sphingomonas sp., Microbacterium sp., Agromyces sp., Bacillus sp. e Acinetobacter sp. Este é o primeiro relato de uma linhagem de Acinetobacter capaz de degradar MCYST. A cinética de biodegradação da MCYST-XR mostrou redução de 80% em 72 horas, período em que as bactérias apresentaram o máximo crescimento. A presença do gene mlrA codificante da enzima microcistinase envolvida no metabolismo da microcistina foi avaliada nos genomas dos seis isolados bacterianos usando iniciadores de PCR específicos. Fragmentos de aproximadamente 800 pb foram amplificados em dois isolados, Bacillus sp.e Microbacterium sp. Ensaios de toxicidade utilizando o cládocero Daphnia similis foram realizados para verificar a efetiva remoção da MCYST-XR e a não formação de subprodutos tóxicos na via de biodegradacão. Os resultados negativos dos bioensaios após 48 horas indicaram a ausência de subprodutos tóxicos na via da degradação.Microcystins are potent hepatotoxins and tumor promoters found in freshwaters that cause public health risks and thus represent a serious problem for water treatment plants. The cyanobacterium genus Microcystis is the most known toxin-producer and the most common bloom-forming in water reservoirs used for public supply. However, some bacteria are able to use these toxins as carbon source, which can contribute to its removal from water. This study assessed the potential for degradation of microcystin-XR (MCYST-XR) by heterotrophic bacteria isolated from a public water supply system of the city of Piracicaba-SP. The cyanotoxin MCYSTXR evaluated was isolated from Microcystis aeruginosa strain NPLJ-4 and purified. Pure cultures of 35 bacteria isolated from the water supply system were tested. For this, each bacterium was inoculated in minimal medium salts containing 60 g mL-1 of purified MCYST-XR and after 144 hours the toxin degradation was evaluated by LC-MS/MS analysis. The peaks indicating the mass of microcystin-XR (m/z 1037) were not detected in the culture medium of six bacteria, which were identified by almost complete sequencing of the 16S rRNA gene as belonging to the genera Pseudomonas sp., Sphingomonas sp., Microbacterium sp., Agromyces sp., Bacillus sp. and Acinetobacter sp. This is the first report of an Acinetobacter strain able to degrade MCYST. The kinetic of the MCYST-XR biodegration showed 80% reduction in 72 hours, period in which the bacteria showed the maximum growth. The presence of the mlrA gene encoding the microcystinase enzyme involved in the metabolism of microcystin was evaluated in the genomes of the six bacterial isolates using specific PCR primers. Fragments of approximately 800 bp were amplified in two isolates, Bacillus sp. and Microbacterium sp. Toxicity assays using the cladoceran Daphnia similis were conducted to verify the effective removal of MCYST-XR and the non formation of toxic by-products in the biodegradation pathway. The negative results of the bioassays after 48 hours indicated absence of toxic by-products in the biodegradation pathway.
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Silva, José Roberto Lins da. "Cianobactérias e cianotoxinas no reservatório da UHE Lajeado, Palmas - TO: fatores condicionantes ao surgimento de floração e avaliação da remoção por meio de uma instalação piloto de dupla filtração." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-02122014-140636/.
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O abastecimento de água na cidade de Palmas - TO vem passando por sérios problemas de ordem quantitativa desde 2005. As gradativas reduções nas vazões de seus mananciais e o aumento da demanda por água tratada contribuem para a escassez deste bem durante o período de estiagem. Não obstante, a solução mais efetiva para solucionar este problema seria a construção de uma nova estação de tratamento aduzida pela água do reservatório da usina hidroelétrica Luis Eduardo Magalhães (UHE Lajeado). Por outro lado, florações de cianobactérias são recorrentes e o controle mais efetivo seria necessário ao processo de tratamento desta água. Alguns gêneros destes microrganismos produzem e liberam toxinas com potencial cancerígeno, além de gerar transtornos ao tratamento em função da alteração do sabor e odor, e aumento da carga orgânica da água a ser tratada. Diante deste cenário, este trabalho buscou compreender os fatores condicionantes ao surgimento de uma floração de cianobactérias, especialmente ocorrida em 01 de junho de 2012, neste reservatório (S 10°17,215\' / 10°11,284\' e W 48°18,729\' / 48º21,874\'), como também, estudar e avaliar a remoção de células de cianobactérias e cianotoxinas, turbidez, matéria orgânica (MO) e biomassa algal, por meio de uma instalação piloto de dupla filtração (IPDF), composta por colunas de pré-filtro ascendente em areia grossa (FAAG) e filtro rápido descendente em areia (FRD), precedidos ou não de oxidante e adsorvente de natureza carbonácea. A taxa de filtração adotada para o FAAG e FRD foi de 180 m3.m-2.d-1. Sobre a floração, foram realizadas quatro campanhas de coleta e análises de água entre os dias 03 e 14 de junho. Dezessete variáveis limnológicas foram avaliadas a montante e a jusante do local da floração. Foi aplicado o índice de estado trófico proposto por Lamparelli (2004) e análises de correlação entre as concentrações de fósforo total. Para o estudo na IPDF, águas enriquecidas de cianobactérias (AE) foram preparadas com densidades em torno de 200.000 cél.mL-1 para serem testadas em cinco configurações, sendo somente a primeira realizada por dois ensaios, e composta por dupla filtração (DP) seguida de carvão ativado granular (FCAG). A segunda, por adsorção em carvão ativado em pó (CAP) antecedendo a DP. A terceira, por pré-oxidação (PreOx) antecedendo a DP e póstratamento com FCAG. A quarta, constituída por PreOx seguida de CAP e posterior DP. A quinta configuração foi composta por coluna de interoxidação entre os filtros e posterior adsorção por FCAG. Para avaliação das etapas durante os ensaios, foram realizadas análises de turbidez, pH, clorofila a, cianotoxinas, série de carbono, e caracterização físico-química, bacteriológica e hidrobiológica das AE. Sobre a floração, foi registrada a dominância de Dolichospermum solitarium, porém sem apresentar toxicidade para as cianotoxinas testadas. O estudo também permitiu concluir que as contribuições do fósforo efluente da ETE Aureny, e das bacias do ribeirão Taquaruçu Grande, córregos Machado e Tiúba, proporcionaram ao ponto onde ocorreu a floração (ponto 3 S 10º17,304\' / W 48°19,968\') um ambiente potencial para o florescimento de cianobactérias. Foi reconhecido também que o efluente da ETE não contribuiu isoladamente para o episódio, e que uma chuva extemporânea, ocorrida no dia do episódio, certamente contribuiu com o aumento do aporte de fósforo advindo da bacia do Taquaruçu Grande (BRT), e, consequentemente, com a desestabilização térmica do ecossistema. Em relação à eficiência de remoção da dupla filtração, foi possível verificar que a variação da composição físico-química, microbiológica e toxicológica nas águas enriquecidas de cianobactérias (AE) influenciou efetivamente no rendimento dos processos testados. A grande vantagem desta variação foi reconhecer que a dupla filtração conseguiu garantir excelentes resultados na qualidade da água final. Presente em todos os ensaios, Planktothrix isothrix apresentou-se como uma espécie de fácil remoção em um sistema de dupla filtração quando aplicado o cloreto de polialumínio. Não houve formação significativa de produtos secundários da desinfecção e cianotoxinas.Water supply in the city of Palmas (Tocantins State) has faced severe quantitative problems since 2005. Gradual reductions in flows of their sources and the increased demand for treated water contribute to its scarcity during the dry period. In this context, the most effective solution to this problem is the construction of a new station for treating the water abstracted from the Lajeado Reservoir (Luis Eduardo Magalhães Hydropower Plant). On the other hand, cyanobacterial blooms are recurrent, which requires a more effective water treatment. Some cyanobacteria genera produce and release carcinogenic toxins, and generate disorders to water treatment due to the change of taste and odor, and increased organic load of water to be treated. This study aimed to determine the factors controlling the emergence of a cyanobacterial bloom, especially on June 1st 2012 in that reservoir (S 10°17,215\' / 10°11,284\' e W 48°18,729\' / 48º21,874\'), and to analyze the removal of cyanobacterial cell and cyanotoxin, turbidity, organic matter (MO) and algal biomass through the use of a double filtration pilot plant (IPDF), made up of upward prefilter columns on coarse sand (FAAG) and rapid downward filter on sand (FRD), preceded or not by oxidant and carbonaceous adsorbent. The filtration rate adopted for FAAG and FRD was 180 m3.m-2.d-1. In relation to the bloom, four samplings to collect and analyze the water were carried out between June 03 and 14. Seventeen limnological variables were evaluated upstream and downstream of the bloom location. The trophic state index proposed by Lamparelli (2004) and analysis of correlation between total phosphorus concentrations were applied. For analysis using the IPDF, waters enriched with cyanobacteria (AE) were prepared with densities of about 200.000 cells.mL-1 to be tested in five setups, only the first was carried out with two assays and consisted of double filtration (DF) followed by granular activated carbon (FCAG). The second consisted of adsorption on powdered activated carbon (CAP) before DF. The third setup was made up of pre-oxidation (PreOx) preceding the DF and post-treatment with FCAG. The fourth comprised of PreOx followed by CAP and DF. The fifth setup consisted of interoxidation column between the filters and subsequent adsorption on FCAG. During the tests, we analyzed turbidity, pH, chlorophyll a, cyanotoxins, carbon series, and performed physical, chemical, bacteriological and hydrobiological characterization of the AE. During the bloom, we registered the dominance of Dolichospermum solitarium, without toxicity for the cyanotoxins tested. The contribution of phosphorus from the effluent of the Aureny WWTP and from the basins of the Taquaruçu Grande, Machado and Tiúba streams provided the site 3 (S 10º17,304\' / W 48°19,968\') with favorable conditions for occurrence of blooms. The effluent of the WWTP did not contribute alone to the event, and an out-of-season rain upon the bloom event certainly contributed to the increased input of phosphorus from the Taquaruçu Grande basin, and consequently to the thermal destabilization of the ecosystem. Regarding the removal efficiency of double filtration, the variation in physical, chemical, microbiological and toxicological composition of the waters enriched with cyanobacteria in fact impacted the performance of the tested processes. The great advantage of this variation was the observation that the double filtration had excellent results to the final water quality. Planktothrix isothrix was present in all tests but was easily removed by double filtration combined with polyaluminum chloride. There was no formation of disinfection byproducts and cyanotoxins.
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Courte, Josquin. "Étude de la propagation prion-like de l'alpha-synucléine dans des réseaux de neurones reconstruits Reconstruction of directed neuronal networks in a microfluidic device with asymmetric microchannels Neurotoxicity of the Cyanotoxin BMAA Through Axonal Degeneration and Intercellular Spreading." Thesis, Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=http://theses-intra.upmc.fr/modules/resources/download/theses/2019SORUS053.pdf.
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Les maladies neurodégénératives (telles que les maladies de Parkinson et d’Alzheimer) sont caractérisées par l’agrégation de protéines mal repliées en dépôts insolubles. Ces dépôts engendrent des dysfonctions cellulaires, et semblent donc avoir un rôle fondamental dans le développement de ces pathologies. L’apparition de ces dépôts se fait de façon stéréotypée dans des sous-groupes de patients. Notamment, dans la maladie de Parkinson, la petite protéine présynaptique alpha-synucléine (aSyn) est le composant principal d’agrégats dénommés corps de Lewy et neurites de Lewy. Les corps et neurites de Lewy apparaissent suivant un patron dénommé « staging de Braak » dans une sous-partie conséquente des patients. Dans une certaine mesure, le patron d’apparition des agrégats semblent suivre la connectivité neuro-anatomique entre les régions cérébrales, ce qui suggère que l’agrégation puisse se propager dans les réseaux neuronaux.L’étude des maladies prions telles que le kuru ou la maladie de Creutzfeldt-Jakob a mis en évidence un mécanisme original de propagation du mérepliement des protéines. La protéine PrP s’agrégeant dans ces pathologies est en effet capable d’adopter au moins deux conformations radicalement distinctes. L’une, pathologique, forme des agrégats, tandis que la forme fonctionnelle ne s’agrège pas. Par des mécanismes encore mal compris, mais qui potentiellement similaires à la formation de fibres amyloïdes, la protéine pathologique est en mesure de convertir la protéine fonctionnelle en sa forme anormale, et à l’inclure dans des agrégats. La forme anormale de la protéine est donc capable de s’auto-propager, et cela de cellule à cellule et d’organisme à organisme. De nombreuses similitudes dans les caractéristiques biochimiques et moléculaires des agrégats présents dans les maladies neurodégénératives non prions ont mené à l’hypothèse que l’agrégation protéique se fait suivant des modalités similaires aux maladies à prions. Suivant ce scénario, l’agrégation protéique est en mesure de se propager de neurone à neurone dans le cerveau via les connexions neuronales, et ainsi suivre un patron stéréotypé dépendant de l’interconnexion des régions successivement touchées. Cette hypothèse est dénommée « prion-like ».Cependant, les mécanismes expliquant la génération d’un patron stéréotypé de développement prion-like des agrégats d’aSyn restent obscurs. Le but de ma thèse a été d’aborder les déterminants de la propagation de l’agrégation de l’aSyn dans des réseaux de neurones hétérogènes grâce à des modèles in vitro. J’ai tout d’abord évalué si différentes régions du cerveau de souris mises en culture primaire présentaient la même vulnérabilité au recrutement de l’aSyn soluble dans des agrégats pathologiques introduits dans le milieu extracellulaire. J’ai pu mettre en évidence que la vulnérabilité de neurones striataux, corticaux et hippocampaux était fortement différente, et que le facteur déterminant cette vulnérabilité était le niveau d’expression endogène de l’aSyn. J’ai ensuite développé un système de culture permettant la reconstruction contrôlée de réseaux de neurones binaires in vitro, composés de neurones primaires murins, dont les connexions sont parfaitement orientées d’un compartiment vers l’autre, un prérequis pour l’étude de la propagation d’un agent pathogène auto-propagatif. Un tel système est parfaitement original, et n’avait jamais été publié auparavant. J’ai finalement modélisé la propagation prion-like de l’aSyn dans de tels réseaux, en y introduisant des agrégats exogènes d’aSyn fluorescents dans le compartiment « présynaptique » et en évaluant la propagation de l’agrégation au compartiment « postsynaptique ». Ce transfert ne peut se faire que via les connexions neuronales poussant depuis le compartiment présynaptique, les deux compartiments étant fluidiquement isolés. [...]Neurodegenerative diseases such as Parkinsons’s or Alzheimer’s diseases are characterized by the aggregation of misfolded proteins in insoluble inclusions. These inclusions trigger cellular dysfnctions and are therefore thought to play an important role in the development of these pathologies. They appear following a conserved pattern in subgroups of patients. In Parkinson’s disease, the small presynaptic protein alpha-synuclein (aSyn) is the main component of protein deposits termed Lewy bodies and Lewy neurites. These appear following a stereotypical pattern known as “Braak staging” in a consequent subset of patients. The pattern of inclusion formation partly follows neuroanatomical connectivity, suggesting that protein aggregation propagates in neural networks. Prion diseases such as kuru or Creutzfeldt-Jakob’s disease have revealed an original mechanism for propagating protein misfolding. The PrP protein, aggregated in these diseases, is able to have two radically distinct conformations. The pathological one aggregates in supramolecular assemblies, while the functional one does not. Through an incompletely understood mechanism which might share similarities with the formation of amyloid fibrils, the pathological form of the protein is able to convert the functional form into the pathological one, recruiting it into aggregates. The abnormal form of the protein is thus able to self-propagate, from cell to cell and from organism to organism. Numerous biochemical and molecular characteristics of aggregates detected in neurodegenerative diseases are shared with the prion aggregates. It is thus hypothesized that protein aggregation in neurodegenerative diseases unfolds in a similar manner to prion aggregation. In this scenario, protein aggregation is able to be transmitted from neuron to neuron following neuroanatomical connectivity, and thus propagates in a stereotypical manner in neural networks following axonal tracts. This scenario is named “prion-like hypothesis”. However, how the prion-like propagation of aSyn generates the conserved pattern of aggregates in the brain of patients is still unknown. The aim of my PhD thesis has been to decipher parameters impacting the prion-like propagation of aSyn in heterogeneous neural networks with in vitro models. I first assessed if specific neuronal populations cultured from various regions of the mouse brain exhibited the same vulnerability to the prion-like recruitment of aSyn in pathological aggregates following their exposure to exogenous aSyn fibrils. I was able to demonstrate that cortical, striatal and hippocampal primary neuronal cultures had a significant difference in their vulnerability to prion-like seeding of aSyn aggregation. I also demonstrated that this vulnerability was due to the differential expression of aSyn in these populations. I then developed a culture system allowing for the controlled reconstruction of primary murine neurons networks. This system allows for the perfect filtration of axonal outgrowth in one direction, thus allowing the reconstruction of fully oriented binary networks. Axonal growth orientation is a prerequisite to the in vitro study of pathogens propagation in neural networks. This system is the first to achieve this level of axonal filtration while allowing synaptic connectivity between the two compartments. I finally modeled aSyn prion-like propagation in these reconstructed networks by selectively introducing exogenous fluorescent aSyn fibrils in the “presynaptic” compartment and following aggregation propagation to the “postsynaptic” compartment. This propagation can only occur through crossing axons, as the two compartments are fluidically isolated. I demonstrated that anterograde aSyn prion-like propagation was relatively inefficient in this experimental framework. Indeed, while a small quantity of exogenous fibrils are transferred to postsynaptic neurons, they are not able to seed endogenous aSyn aggregation in those. [...]
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Buch, Bruna. "Caracterização taxonômica e prospecção de toxinas de cianobactérias bentônicas de ambientes lênticos da região noroeste do estado de São Paulo." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/180623.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
As cianobactérias são importantes componentes das comunidades aquáticas em diversos ecossistemas, graças a longa história evolutiva do grupo que desenvolveu diversas adaptações fisiológicas e citológicas que permitiram a sua dominância ao redor do globo. As cianobactérias são também os bactérias fotossintetizantes com a morfologia mais diversificada e, embora essa qualidade tenha sido extensivamente utilizada pelos cientistas para a delimitação dos táxons e reconstrução da história evolutiva, vem perdendo cada vez mais espaço para o uso de marcadores moleculares, os quais são capazes de inferir relações filogenéticas mais robustas e que mais proximamente refletem o percurso evolutivo traçado por esses microrganismos. Desse modo, o objetivo da realização deste estudo foi caracterizar taxonomicamente populações de cianobactérias bentônicas de ambientes lênticos da região noroeste do estado de São Paulo, utilizando uma abordagem polifásica, por meio do uso do gene rRNA 16S e da estrutura secundária do ITS 16S-23S, além de considerar aspectos morfológicos e ecológicos. Como resultado deste trabalho, 41 populações de cianobactérias bentônicas foram avaliadas, sendo alocadas em 15 gêneros distribuídos em 11 famílias e cinco ordens. A ordem Oscillatoriales foi a mais representativa entre as populações estudadas (68,3%, 28 populações), seguida pela ordem Synechococcales (19,5%, 8 populações). A análise filogenética do gene RNAr 16S foi capaz de revelar a presença de táxons crípticos, que embora apresentem morfologia correspondente com táxons já descritos, formaram clados separados, indicando se tratarem de táxons ainda não conhecidos, e esse foi o caso de 13 populações aqui estudadas. Parte dos táxons crípticos foi trabalhada em maior profundidade, resultando em três manuscritos apresentados na forma de capítulos que correspondem à descrição dos novos gêneros e espécies Koinonema pervagatum (Capítulo III) e Blennothricopsis periphytica (Capítulo IV), além da descrição de três novas espécies para o gênero Phormidium (Capítulo V), com o registro da primeira espécie bentônica produtora de microcistina para o estado de São Paulo. Embora a prospecção dos genótipos tóxicos, utilizando marcadores específicos para os genes mcyE e sxtA responsáveis pela síntese de microcistinas e saxitoxinas, respectivamente, tenha revelado apenas uma linhagem tóxica, esse resultado é positivo do ponto de vista de impactos relacionados à presença de cianobactérias em corpos d’água para uso público. Entretanto, mostra a importância dos estudos de prospecção de toxinas em cianobactérias bentônicas no Brasil, ainda pouco explorados.
Cyanobacteria are important components of aquatic communities in different ecosystems, thanks to its long evolutionary history that provided several physiological and ecological adaptations, allowing them to spread around the globe. Cyanobacteria are also the most morpological diversified photossintetic bacterial group and, despite many taxonomists have extensively used this character to delimit taxa and to reconstruct their evolutionary history, it has been losing its prominence to molecular markers, which are most suited to infer robust phylogenetic relationships that properly reflect the evolutionary path followed by these organisms. Therefore, the aim of the study was to taxonomically characterize benthic cyanobacterial populations in lentic habitats from the Northwest region of São Paulo state, using a polyphasic approach, through the phylogenetic analysis of the 16S rRNA gene and the 16S 23S ITS secondary structure, aside from morphological and ecological aspects. As result, 41 benthic cyanobacterial populations were evaluated and assigned to 15 genera distributed in 11 families and five orders. The Oscillatoriales order was the most representative among all (69.3%, 28 populations), followed by the Synechococcales (19.5%, eight populations). The 16S rRNA phylogenetic analysis revealed the presence of cryptotaxa, which, despite morphologically ressembling previously described taxa, formed separated clades, suggesting not yet acknowledged taxa. That was the case of 13 populations studied. Some of these cryptotaxa were deeper evaluated in three manuscripts presented here as chapters and described as the new genera and species Koinonema pervagatum (Chapter III) and Blennothricopsis periphytica (Chapter IV), the description of three new species from the Phormidium genus (Chapter V) and the first record of a benthic microcystin producing cyanobacteria in the São Paulo state. Although the toxic genotypes prospection using specific molecular markers for the mcyE and sxtA genes, responsible for microcystin and saxitoxin production, respectively, revealed only one toxic strain, it demonstrates a positive result regarding the impact caused by toxic cyanobacterial strains in waters for public use worldwide. However, it highlights the importance of studies on potentially toxic benthic cyanobacterial communities, still little explored in Brazil.
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Villars, Kathryn E. Villars. "Removal of Microcystin-LR from Drinking Water Using Granular Activated Carbon." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1532007603377473.
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Pinheiro, Carlos Filipe Carvalho. "Joint toxicity effects of cyanotoxins and chemical compounds." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/10480.
Full textAbstract:
Mestrado em Biologia Aplicada - Toxicologia e EcotoxicologiaOs organismos aquáticos podem estar constantemente expostos a cianotoxinas e contaminantes antropogénicos provenientes das florescências de cianobactérias e das atividades humanas, respetivamente. A microcistina-LR (MC-LR) e a cilindrospermopsina (CYN) são as cianotoxinas mais frequentemente detetadas nas florescências de cianobactérias e têm sido encontradas simultaneamente na água. Os metais e pesticidas são contaminantes antropogénicos normalmente encontrados no ambiente aquático como resultado da intensificação das atividades agrícolas e industriais. O cádmio (Cd) e a terbutilazina (TBA) foram selecionados como exemplos de metais e pesticidas que podem co-ocorrer com cianotoxinas no ambiente. No entanto, o risco ecotoxicológico combinado de cianotoxinas e/ou contaminantes antropogénicos existentes no ambiente aquático é ainda pouco conhecido. O presente trabalho teve como objetivo identificar alguns padrões e comportamentos biológicos relativamente a este tipo de combinações. Os efeitos de misturas binárias de MC-LR, CYN, Cd e TBA foram avaliados nas taxas de crescimento da alga Chlorella vulgaris após 4 e 7 dias de exposição, usando o modelo de referência de ação independente (AI). A ferramenta MIXTOX foi usada para avaliar possíveis desvios ao modelo de referência (devido a interações entre compostos), tais como sinergismo/antagonismo, dependência da dose ou do rácio da mistura. Os resultados demonstraram vários padrões de resposta, dependendo da mistura binária testada. Foi detetado sinergismo na mistura de MC-LR e CYN em ambos os períodos de exposição. Na mistura de MC-LR e TBA, houve um desvio dependente do nível da dose entre os componentes para ambos os períodos de exposição, onde se observou antagonismo e sinergismo para concentrações baixas e elevadas de ambos os compostos, respetivamente. Na mistura de MC-LR e Cd, registou-se antagonismo após 4 dias de exposição e um desvio dependente do nível da dose entre os componentes após 7 dias de exposição, observando-se sinergismo e antagonismo para concentrações baixas e elevadas de ambos os compostos, respetivamente. Embora na mistura de CYN e TBA se tenha observado um desvio dependente do rácio entre os componentes, com um padrão de antagonismo perante a dominância da CYN, na mistura de CYN e Cd observou-se antagonismo após 4 dias de exposição. Após 7 dias de exposição foi observado um padrão semelhante de resposta em ambas as misturas contendo CYN, ou seja, um desvio dependente do nível da dose entre os componentes na qual se observou sinergismo para as concentrações baixas e antagonismo para as concentrações elevadas testadas de ambos os compostos. Para a mistura de TBA e Cd, registou-se antagonismo após 4 dias de exposição e um desvio dependente do nível das doses entre os componentes (antagonismo para concentrações baixas e sinergismo para concentrações elevadas de ambos os componentes) após 7 dias de exposição. Devido à diversidade de efeitos e comportamentos que podem resultar da combinação de tóxicos bastante comuns, este estudo mostra a importância de avaliar os efeitos combinados de cianotoxinas e/ou contaminantes antropogénicos.
Aquatic organisms may be exposed to cyanotoxins and anthropogenic contaminants originated from harmful cyanobacterial blooms and human activities, respectively. Microcystin-LR (MC-LR) and cylindrospermopsin (CYN) are the most frequently detected cyanotoxins in harmful cyanobacterial blooms and have been simultaneously reported in the water. Metals and pesticides are anthropogenic contaminants commonly found in the aquatic environment as a result of the intensification of agricultural and industrial activities. Cadmium (Cd) and terbuthylazine (TBA) were chosen as an example of the possible metals and pesticides that can co-occurr with cyanotoxins in the environment. However, the ecotoxicological risk of combinations of cyanotoxins and/or anthropogenic contaminants in the aquatic environment needs more studies. The present work aimed to elucidate some biological behaviours and patterns regarding these combinations. The effects of binary mixtures of MC-LR, CYN, Cd and TBA on the growth rate of the freshwater algae Chlorella vulgaris were assessed after 4 and 7 days of exposure using the reference model of independent action (IA). The MIXTOX tool was used to detect possible deviations (due to the interaction between compounds) from the reference model such as synergism/antagonism, dose ratio and dose level dependency. The results demonstrated that several patterns of response were obtained depending on the binary mixture. Synergism was detected in the mixture of MC-LR and CYN for the two exposure periods. In the MC-LR and TBA mixture, a dose-level deviation was observed for the two exposure periods indicating antagonism at low dose levels and synergism at high dose levels. In the MC-LR and Cd mixture, deviations for antagonism were found for a 4-day exposure period while a dose-level deviation was observed for a 7-day exposure period showing synergism at low dose levels and antagonism at high dose levels. A dose-ratio deviation was observed in the CYN and TBA mixture, with a pattern for antagonism when CYN was the compound dominant, while deviations for antagonism were observed in the CYN and Cd mixture for a 4-day exposure period. Similar patterns of response were obtained for both mixtures involving CYN after 7 days of exposure, namely dose-level deviation indicating synergism at low dose levels and antagonism at high dose levels. For TBA and Cd mixture, antagonism was found for a 4-day exposure period and a dose-level deviation (antagonism at low dose levels and synergism at high dose levels) was observed for a 7-day exposure period. Due to the diversity of effects and behaviours that can result from the combination of very common toxicants, this study shows the importance of evaluating the combined effects of cyanotoxins and/or anthropogenic contaminants.
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Baganz, Daniela. "Comparing locomotor behaviour of the fish species Danio rerio and Leucaspius delineatus under the influence of chemical stressors." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2006. http://dx.doi.org/10.18452/15474.
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Diese Dissertation ist ein Beitrag zum Forschungsfeld der Stressökologie, im Spe-ziellen der Verhaltensökotoxikologie. Das spontane lokomotorische Verhalten der Fischarten Danio rerio und Leucaspius delineatus wurde unter sublethaler Expo-sition mit dem Cyanobakterientoxin Microcystin-LR (MC-LR) und dem Xenobio-tikums 2.4.4`-Trichlorobiphenyl (PCB 28) quantifiziert. Die Schwimmgeschwin-digkeit und Anzahl der Wendungen wurden kontinuierlich mit einem automati-schen Video-Monitoringsystem unter Laborbedingungen aufgezeichnet. In Hin-blick auf zyklische Aspekte wurden die Verhaltensanalysen mit chronobiologi-schen Methoden kombiniert. Hiermit wurde gezeigt, dass MC-LR und PCB 28 zu signifikanten Effekten in Verhalten und Aktivitätsrhythmik beider Fischarten führten. Höhere Konzentrati-onen beider Untersuchungssubstanzen verursachten eine deutliche Aktivitätsredu-zierung bei Danio rerio und Leucaspius delineatus. Einige der festgestellten Do-sis-Wirkungsbeziehungen entsprechen der Hormesistheorie, z. B. war bei geringe-ren MC-LR Konzentrationen ein Aktivitätsanstieg und bei höheren ein Aktivitäts-abfall beider Fischarten zu verzeichnen. Die Exposition mit MC-LR und PCB 28 verringerte bei beiden Testfischarten die Synchronisation der Aktivität mit dem Zeitgeber Licht. Dies führte bei beiden Fischarten zu einer Phasenverschiebung. Bei Leucaspius delineatus war unter dem Einfluss von MC-LR eine Phasenumkehr zu verzeichnen, die Fische wechselten von Tag- zu Nachtaktivität. Die Cosinor Analyse zeigte Dosis abhängige Veränderungen der circadianen Rhythmen der Schwimmaktivität (z.B. MESOR, Akrophase) unter Einfluss von MC-LR und PCB 28 an. Die Power Spektral Analyse indizierte für beide Fischar-ten unter Einwirkung von MC-LR and PCB 28 eine reduzierte Dominanz des cir-cadianen Rhythmuspeaks. Da die registrierten Unterschiede in der Reaktion beider Fischarten auf MC-LR und PCB 28 eher gering waren, sind Ergebnisse der Art Danio rerio, die häufig in Toxizitätstests verwendet wird, mit denen der einheimischen Art Leucaspius deli-neatus vergleichbar. Die Ergebnisse belegen, dass Verhaltensuntersuchungen in Kombination mit chronobiologischen Auswertemethoden eine sensitive und zuverlässige Abschät-zung des Gefährdungspotentials von Substanzen sowohl auf dem Gebiet der Öko-toxikologie als auch für Biomonitoring ermöglichen.This thesis contributes to the field of stress ecology specifically behavioural ecotoxicology. The spontaneous locomotor behavior of two fish species Danio re-rio and Leucaspius delineatus was recorded and quantified continuously under sublethal exposure to the cyanotoxin microcystin-LR (MC-LR) and the xenobioti-cum 2.4.4`-trichlorobiphenyl (PCB 28). By using an automated video-monitoring system, the swimming velocity and the number of turns were assessed under labo-ratory conditions. For analysing cyclic aspects basic behavioural analyses were combined with chronobiological procedures as cosinor analysis and power spec-tral analysis. Both MC-LR and PCB 28 acted as stressors and caused significant changes in the behaviour and circadian activity rhythms of Danio rerio as well as Leucaspius de-lineatus. So for both species elevated concentrations of the stressors led to a re-duction of their activity. Some dose-responses correspond to the hormesis theory, e.g., there was an increase of daytime activity at lower MC-LR concentrations and a decrease at elevated concentrations of MC-LR for both species. A degree of desynchronisation of activity to the zeitgeber light, which led to a phase shift was caused by the chemicals in both fish species. In Leucaspius de-lineatus this shift was so drastic that this species reversed their significant diurnal activity and became nocturnal under the influence of MC-LR. The Cosinor analysis revealed MC-LR- and PCB 28-induced, dose-dependent al-terations of the circadian rhythms of activity (e.g., MESOR, acrophase). The power spectral analysis showed that the dominance of the circadian rhythmic peak (of 24 h) was reduced under MC-LR and PCB 28 for both species. Since the observed differences in the reactions of both species to MC-LR and PCB 28 were rather small, the results of the species Danio rerio which is widely used for environmental risk assessment tests, are comparable to those of the native European species Leucaspius delineatus. The findings of this study proved that the basic behavioural analyses combined with chronobiological procedures could be valuable tools for the study of stressful or even harmful environmental factors in the field of ecotoxicology as well as for biomonitoring.
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Filatova, Daria. "Origin and release of cyanotoxins in surface water reservoirs." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/672226.
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Cyanobacteria are prokaryotes and components of regular periphyton formation. Overall, there are around 2000 cyanobacterial species that live in various environments. Some cyanobacterial species are known to form blooms, which can cause harmful effects when blooms’ intensity is high. Abundant blooms can deplete oxygen causing hypoxic conditions that may result in the death of plants and animals. Another major issue associated with bloom-forming cyanobacteria is the production of bioactive secondary metabolites, some of which are known to be toxic. One of the main routes of human exposure to cyanobacterial toxins occurs through water, both drinking and recreational water use. There are two main drivers that favour cyanobacteria bloom: nutrient over-enrichment and on-going climate change. Nowadays, little quantitative information is available on temporal variations of cyanotoxins, including the European region. Establishing seasonal trends of cyanobacterial toxins will promote the development of effective water management strategies.
Cyanotoxins can be divided into two main groups according to their targeted tissue/organ of toxicity: hepatotoxins and neurotoxins. Main cyanobacterial hepatotoxins are microcystins, nodularins, and cylindrospermopsin, while anatoxin-a, and saxitoxin are the main neurotoxins. Owning to posed toxicological risks by various cyanobacterial metabolites, guidelines values in drinking water have been introduced by several countries. What is more, the update of the WHO guideline has been recently finalized, and now it involves threshold values not only for microcystin variant, but also for cylindrospermopsin, anatoxin-a, and saxitoxins. The assessment of the occurrence and the risks of the exposure to cyanotoxins require robust, straightforward, and sensitive analytical methodologies for their identification and quantitation in the aquatic environment, and particularly in drinking water reservoirs. Besides, to perform extensive monitoring studies, these methods should be cost- effective and rapid.
Beyond these cyanotoxins, cyanobacteria can produce a variety of other bioactive secondary metabolites, including cyanopeptides. These compounds belong to several classes including cyanopeptolins, anabaenopeptins, aeruginosins, aerucyclamides, and microginins. Some of these compounds are known to be co-produced together with other cyanobacterial toxins. Compounds from these classes have shown acute toxicity in planktonic grazers and are able to inhibit various enzymes. However, there is a knowledge gap in both their occurrence and posed toxicological risks.
In the framework of this thesis, several points were addressed in order to fulfil the current
gaps of the research in the area of occurrence of cyanobacterial toxins ant other metabolitesin surface water. Literature review on current analytical approaches for analysis of cyanotoxins and their seasonal variations in previously conducted studies in European region was carried out. Main analytical approaches were compared, what provided solid background for analytical method development. Based on available seasonal studies on cyanotoxins in different European climate zones, patterns for continental, Mediterranean, and oceanic climate zones were described.
A method for the assessment of multiclass cyanotoxins in freshwater based on dual solid-
phase extraction liquid chromatography coupled with high-resolution mass spectrometry was developed, optimised, and validated. The developed method showed high sensitivity, selectivity, and robustness. The application of an ultra-high pressure liquid chromatography column allowed fast separation, what makes this method more cost-effective.
A targeted method was applied for the analysis of freshwater samples from Spain,
Switzerland, and the United Kingdom. Several targeted cyanotoxins were identified and quantified. Additionally, mass spectrometry data acquired in high resolution provided an opportunity of posterior suspect screening, which revealed potential presence of another cyanopeptide – anabaenopeptin.
Additionally, the targeted methodology was expanded for an application of suspect
screening for a wide range of cyanopeptides. This method was applied for the analysis of raw drinking water from the United Kingdom. Suspect screening revealed co-occurrence of targeted compounds together with other cyanopeptides. The obtained results are the first to present concentrations of anabaenopeptins, cyanopeptolins, aeruginosins, and microginins, along with microcystins, in the reservoirs of the United Kingdom.Las cianobacterias son procariotas y componentes de la formación regular de perifiton. En general, hay alrededor de 2000 especies de cianobacterias que viven en varios entornos. Se sabe que algunas especies de cianobacterias generan episodios de proliferación de toxinas, que pueden causar efectos nocivos cuando la intensidad de dicha proliferación es alta. Las proliferaciones abundantes pueden agotar el oxígeno y causar condiciones hipóxicas que pueden resultar en la muerte de plantas y animales. Otro problema importante asociado con las cianobacterias que conllevan dichas proliferaciones es la producción de metabolitos secundarios bioactivos, algunos de los cuales se sabe que son tóxicos. Una de las principales vías de exposición humana a las toxinas cianobacterianas se produce a través del agua, tanto las de consumo como las de uso recreativo. Hay dos factores principales que favorecen la proliferación de las cianobacterias: el enriquecimiento excesivo de nutrientes y el cambio climático continuo. En la actualidad, se dispone de poca información cuantitativa sobre las variaciones temporales de las cianotoxinas, incluida la región europea. Sin embargo, comprender las tendencias históricas es fundamental, ya que reduce la incertidumbre y proporciona una base sólida para la previsión de dichos episodios. El establecimiento de tendencias estacionales de toxinas cianobacterianas promoverá el desarrollo de estrategias efectivas para la gestión del agua. Las cianotoxinas se pueden dividir en dos grupos principales según su tejido / órgano de toxicidad objetivo: hepatotoxinas y neurotoxinas. Las principales hepatotoxinas cianobacterianas son microcistinas, nodularinas y cilindrospermopsina, mientras que la anatoxina-a y la saxitoxina son las principales neurotoxinas. Debido a los riesgos toxicológicos que plantean varios metabolitos de las cianobacterias, varios países han introducido valores de referencia en el agua potable. Es más, la actualización de la guía que la OMS ha finalizado recientemente incluye ahora valores umbral no solo para la variante de microcistina, sino también para cilindrospermopsina, anatoxina-a y saxitoxinas. La evaluación de la presencia y los riesgos de la exposición a las cianotoxinas requieren metodologías analíticas sólidas, sencillas y sensibles para su identificación y cuantificación en el medio acuático y, en particular, en los reservorios de agua potable. Además, para realizar estudios de seguimiento exhaustivos, estos métodos deben ser rentables y rápidos. Más allá de estas cianotoxinas, las cianobacterias pueden producir una variedad de otros metabolitos secundarios bioactivos, incluidos los cianopéptidos. Estos compuestos pertenecen a varias clases que incluyen cianopeptolinas, anabaenopeptinas, aeruginosinas, aeruciclamidas y microgininas. Se sabe que algunos de estos compuestos se coproducen junto con otras toxinas cianobacterianas. Los compuestos de estas clases han mostrado toxicidad aguda en herbívoros planctónicos y son capaces de inhibir varias enzimas. Sin embargo, existe una laguna de conocimiento tanto con respecto a su aparición como a los riesgos toxicológicos que plantean. En el marco de esta tesis, se abordaron varios puntos con el fin de cubrir los vacíos actuales de la investigación en el área de la presencia y distribución de toxinas cianobacterianas y otros metabolitos en aguas superficiales. Se llevó a cabo una revisión de la literatura sobre los enfoques analíticos actuales para el análisis de cianotoxinas y sus variaciones estacionales en estudios realizados anteriormente en la región europea. Se compararon los principales enfoques analíticos que proporcionaron una base sólida para el desarrollo de métodos analíticos. Sobre la base de los estudios estacionales disponibles sobre cianotoxinas en diferentes zonas climáticas europeas, se establecieron patrones para las zonas climáticas continentales, mediterráneas y oceánicas. Se desarrolló, optimizó y validó un método para la evaluación de cianotoxinas multiclase en agua dulce basado en cromatografía líquida de extracción en fase sólida dual combinada con espectrometría de masas de alta resolución. El método desarrollado una alta sensibilidad, selectividad y robustez. La utilización de una columna de cromatografía líquida de ultra alta presión permitió una separación rápida, lo que hace que este método sea más rentable. Se aplicó un método dirigido para el análisis de muestras de agua dulce de España, Suiza y Reino Unido. Se identificaron y cuantificaron varias cianotoxinas dirigidas. Además, los datos de espectrometría de masas adquiridos en alta resolución brindaron la oportunidad de realizar una detección posterior de sospechosos, lo que reveló la presencia potencial de otro cianopéptido: la anabaenopeptina. Además, el método dirigido se amplió para la detección de compuestos sospechosos en relación a una amplia gama de cianopéptidos. Este método se aplicó para el análisis de agua potable del Reino Unido. El cribado de sospechosos reveló la coexistencia de compuestos diana junto con otros cianopéptidos. Los resultados obtenidos son los primeros en presentar concentraciones de anabaenopeptinas, cianopeptolinas, aeruginosinas y microgininas, junto con microcistinas, en los reservorios de agua del Reino Unido.
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Zhao, Cen. "Advanced Oxidation Processes of Problematic Toxin and Water Contaminants: Cylindrospermopsin, Iopamidol, 4-methylcyclohexane Methanol and Propylene Glycol Phenyl Ether." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2235.
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The occurrences of cyanotoxin and organic contaminants threaten drinking water sources and are a serious human health and environmental concern. The control of these problematic contaminants and the remediation of the associated contaminants are critical for ensuring safe drinking water to significant populations. Advanced oxidation processes (AOPs) have received considerable attention as a potential water treatment for various pollutants. In this dissertation, advanced oxidative degradation of four problematic water toxic contaminants (CYN, iopamidol, 4-methylcyclohexane methanol and propylene glycol phenyl ether) were studied to develop the fundamental understanding required to assess AOPs as a potential water treatment process.
UV and visible light activated (VLA) TiO2 photocatalysis using nitrogen and fluorine-TiO2 (NF-TiO2), phosphorus and fluorine-TiO2 (PF-TiO2) and sulfur-TiO2 (S-TiO2) were employed for degradation of 6-hydroxymethyl uracil (6-HOMU), a model compound for the potent cyanotoxin cylindrospermopsin (CYN). NF-TiO2 exhibits the most photoactive, followed by marginally active PF-TiO2 and inactive S-TiO2 under visible light irradiation. Our results indicate that O2-• plays an important role in VLA TiO2 photocatalysis.
Fe (VI), an environmentally friendly oxidant, was employed for the degradation of CYN and 6-HOMU over a range of pH (7 ~ 9.5). The second order rate constants for the reaction of Fe (VI) with CYN decrease from 38.83 ± 0.07 M-1s-1 at pH 7 to 5.02 ± 0.04 M-1s-1 at pH 9.5. Fe (VI) mediated reactions primarily occur via oxidation of the uracil ring in CYN. ELISA results demonstrate that Fe (VI) oxidation process leads to a significant decrease in the bioactivity of CYN as a function of treatment time.
Fe (III)-oxalate/H2O2 process was employed for the remediation of iopamidol, a model for ICM, to determine the formation rates and steady concentrations of •OH and O2-• under UV and visible light irradiation. Reduction by CO2-• and oxidation by •OH contribute to the degradation pathways.
Pulse and gamma radiolysis of 4-methylcyclohexane methanol (MCHM) and propylene glycol phenyl ether (PPh) were studied to determine the bimolecular rate constants and reaction pathways. •OH addition to ortho and para positions in PPh are the predominant reaction pathways; H-abstraction are the primary reaction mechanisms for ∙OH mediated oxidation of MCHM
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Lahr, Rebecca Halvorson. "Advanced Applications of Raman Spectroscopy for Environmental Analyses." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/54010.
Full textAbstract:
Due to an ever-increasing global population and limited resource availability, there is a constant need for detection of both natural and anthropogenic hazards in water, air, food, and material goods. Traditionally a different instrument would be used to detect each class of contaminant, often after a concentration or separation protocol to extract the analyte from its matrix. Raman spectroscopy is unique in its ability to detect organic or inorganic, airborne or waterborne, and embedded or adsorbed analytes within environmental systems. This ability comes from the inherent abilities of the Raman spectrometer combined with concentration, separation, and signal enhancement provided by drop coating deposition Raman (DCDR) and surface-enhanced Raman spectroscopy (SERS).
Herein the capacity of DCDR to differentiate between cyanotoxin variants in aqueous solutions was demonstrated using principal component analysis (PCA) to statistically demonstrate spectral differentiation. A set of rules was outlined based on Raman peak ratios to allow an inexperienced user to determine the toxin variant identity from its Raman spectrum. DCDR was also employed for microcystin-LR (MC-LR) detection in environmental waters at environmentally relevant concentrations, after pre-concentration with solid-phase extraction (SPE). In a cellulose matrix, SERS and normal Raman spectral imaging revealed nanoparticle transport and deposition patterns, illustrating that nanoparticle surface coating dictated the observed transport properties. Both SERS spectral imaging and insight into analyte transport in wax-printed paper microfluidic channels will ultimately be useful for microfluidic paper-based analytical device (𝜇PAD) development. Within algal cells, SERS produced 3D cellular images in the presence of intracellularly biosynthesized gold nanoparticles (AuNP), documenting in detail the molecular vibrations of biomolecules at the AuNP surfaces. Molecules involved in nanoparticle biosynthesis were identified at AuNP surfaces within algal cells, thus aiding in mechanism elucidation.
The capabilities of Raman spectroscopy are endless, especially in light of SERS tag design, coordinating detection of analytes that do not inherently produce strong Raman vibrations. The increase in portable Raman spectrometer availability will only facilitate cheaper, more frequent application of Raman spectrometry both in the field and the lab. The tremendous detection power of the Raman spectrometer cannot be ignored.Ph. D.
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Silva, José Roberto Lins da. "Dinâmica de cianobactérias e cianotoxinas em um braço do reservatório da usina hidroelétrica Luiz Eduardo Magalhães e suas implicações para o abastecimento público de Palmas - TO." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/19014.
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O trabalho apresenta resultados de um estudo sobre a dinâmica de cianobactérias e cianotoxinas e suas relações com variáveis climáticas, bióticas e abióticas do braço do reservatório da usina hidroelétrica Luiz Eduardo Magalhães (UHE Lajeado), em Palmas, Tocantins. O reservatório abrange 626 km2, extensão de 172 km, volume operacional de 4,9.109 m3, tempo de residência da água de 24 dias e uma área de drenagem de 184.219 km². O objetivo principal do estudo foi conhecer a dinâmica espacial e temporal de cianobactérias e cianotoxinas, bem como as suas implicações para o abastecimento público. Os resultados demonstraram que o ponto amostrado no período entre julho e dezembro de 2008, através do estudo de perfil vertical (PVJD), apresentou condições meso-eutróficas, com circulação do tipo polimítica, com estratificação transitória no final do período de seca e isotermia no período chuvoso. Os estudos nictemerais 1 (NIC-1), realizado em 29 de setembro de 2008, e 2 (NIC-2), realizado em 23 de março de 2009, comportaram-se sob condições climatológicas distintas, apresentando o segundo estudo características limnológicas inversas a do primeiro, marcadas principalmente pelas intrusões via tributários. As principais variáveis que influenciaram o padrão de distribuição das cianobactérias no sistema para os estudos foram: climáticas (ventos, precipitação e temperatura); físicas (turbidez e circulação térmica), e químicas (fósforo reativo solúvel e fósforo total). Em relação ao índice de estado trófico - IET, o ambiente foi classificado como eutrófico, para os estudos NIC-1 e 2, e oscilando entre mesotrófico e eutrófico em PVJD. O segundo estudo compreendeu uma avaliação mensal, entre os meses de janeiro de 2006 e dezembro de 2008. Os resultados demonstraram que o ponto 1 se comportou como ambiente em estado de meso-eutrofia, com regime de mistura polimítico, durante o ano de 2008. Neste mesmo ano, a temperatura do ar e a radiação solar foram as variáveis climáticas melhor correlacionadas positivamente com as variações de cianobactérias. Durante os períodos de estiagem dos três anos monitorados o nitrogênio total e o fósforo total definiram os padrões de distribuição de cianobactérias no ponto 1, através de razões inferiores a 10:1. Este ponto comportou-se como ambiente lêntico no período de estiagem, sofrendo influências do reservatório, e como ambiente lótico no período chuvoso, sob influências de fluxos do ribeirão Taquarussu Grande. O estudo também detectou a formação de três florações de cianobactérias no período de estiagem dos anos de 2007 e 2008 no ponto 1. A maior densidade de cianobactérias foi evidenciada em novembro de 2007 (28600 cél.mL-¹). A maior concentração de cianotoxinas ocorreu em julho de 2008, (>2,0 μg.L-¹ de microcistinas), nos pontos 1 e 3. Em relação à viabilidade para abastecimento público, os resultados de turbidez e clorofila-a sugerem a dupla-filtração como sendo a tecnologia capaz de remover cerca de 73,33% destas variáveis. De maneira geral, os dados obtidos neste trabalho sugerem a elaboração de um programa de avaliação sistemática destas toxinas e seus potenciais produtores nos pontos 1, 3, e foz do braço no reservatório. A modelagem ecológica subsidiaria a visualização de cenários futuros, e consequentemente, colaboraria na garantia da qualidade da água produzida pela empresa de abastecimento, no uso desta água para consumo humano.This paper presents results of the study on the dynamic of cyanobacteria and cyanotoxins and their relationship with climatic, biotic and abiotic variables in the hydroelectric Luiz Eduardo Magalhães, Palmas (Tocantins-Brazil) reservoir. The reservoir has 626 km², is 172 km long, operating volume 4,9.109 m³, residence time 24 days, and adrainage area of 184.219 km². The main objective was to study the spatial and temporal dynamics of cyanobacteria and cyanotoxins, as well as its implications for public supply. The results showed that, between July and December 2008, the vertical profile of the studied site (PVJD) was meso-eutrophic, a polymictic mixing regime with stratification at the end of the dry season in a transitional period, and isotherm in the rainy season. Diel studies 1 (NIC-1) and 2 (NIC-2) revealed distinct climatic conditions, showed characteristics opposite, mainly by advection of intrusions via tributaries. In both occasions the main variables that affected the pattern of distribution of cyanobacteria were wind, precipitation and temperature), physical (turbidity, residence time, thermal circulation, orthophosphate and total phosphorus. The sampled area was classified as eutrophic, for studies NIC-1 and 2, and ranged from mesotrophic and eutrophic in PVJD. The second study included a monthly assessment, between January 2006 and December 2008. The results showed that sampling station 1 behaved as a meso-eutrophic environment in 2008. In that same year, the air temperature and solar radiation were the climatic variables that correlated most positively with changes in cyanobacteria. During the dry periods for the three monitored years the total nitrogen and total phosphorus defined the distribution patterns of cyanobacteria dynamics in the sampling station 1. This sampling station behaved as a lentic habitat in the dry season, associated with the reservoir, and as lotic in the rainy season, associated with the river Taquarussu Grande. The study also detected the occurrence of three cyanobacterial blooms in the dry season of the years 2007 and 2008 in section 1. The highest density of cyanobacteria was found in November 2007 (28600 cell.mL-¹). The highest concentration of cyanotoxins occurred in July 2008, (<2.0 μg.L-¹ microcystins) in sampling stations 1 and 3. Regarding the feasibility of this area for public supply, the results suggested the adoption of conventional treatment system. However, some peculiarities of water quality suggested that dual-filtration would be more adequate, due to the incoming effluents of the sewage treatment station Aureny in the sampling station 1. Overall, the data obtained throughout this study points to the maintenance of another two years of systematic evaluation of these toxins and their potential producers form sampling points1 and 3 to the estuary of the arm in the reservoir. The hydrological modelling of future scenarios will help to evaluate this area as source of water for human supply.
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Zhang, Geshan. "The Degradation of Cyanotoxins by using Polymorphic Titanium Dioxide Based Catalysts." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406810827.
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Liu, Yen-Ling. "The Fate of Cyanotoxins in Drinking Water Sources and Treatment Processes." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1515021263671957.
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Lawson, Gabriella Marie. "Seasonal Nutrient Limitations of Cyanobacteria, Phytoplankton, and Cyanotoxins in Utah Lake." BYU ScholarsArchive, 2021. https://scholarsarchive.byu.edu/etd/9183.
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Excess nutrients from human activity trigger toxic cyanobacterial and algal blooms, creating expansive hypoxic dead zones in lakes, damaging ecosystems, hurting local economies, undermining food and water security, and directly harming human health. To identify when and where nutrients limit phytoplankton and cyanobacterial growth, and cyanotoxin concentrations across Utah Lake, USA we conducted four in-situ bioassay studies (563 cubitainers or experimental units) that experimentally added N, P or N+P over the spring, early summer, summer, late summer, and fall in lake water from the top 20 cm of the water column. For our purpose, we defined total phytoplankton as all prokaryotic or eukaryotic organisms containing chlorophyll-a. We evaluated changes in chlorophyll-a and phycocyanin concentrations; the abundance of cyanobacterial species and total phytoplankton species or divisions; cyanotoxin concentrations of the microcystin, anatoxin-a, and cylindrospermopsin; DIN, SRP, TP, and TN concentrations; and other water chemistry parameters. We found that the nutrient limitation of cyanobacteria, and to a lesser extent phytoplankton, was influenced by season and space. Cyanobacteria were often co-limited in the spring or early summer, limited by a single nutrient in the summer, and not limited by N or P in the late summer and fall. Alternatively, phytoplankton were co-limited from the summer into the fall in the main body of the lake and either N limited or co-limited continually in Provo Bay. Microcystis, Aphanocapsa, Dolichospermum, Merismopedia, and Aphanizomenon spp., and Aulacoseira and Desmodesmus spp. and two taxonomical categories of algae (i.e., unicellular and colonial green algae) were primarily associated with cyanobacteria and phytoplankton nutrient limitations. Concentrations of the three cyanotoxins demonstrated a seasonal signal and loosely followed the growth of specific cyanobacteria but was not dependent on total cyanobacterial cell density. The DIN and SRP were biologically available in all water and nutrient treatments with nutrient concentrations declining over the incubation period, suggesting that nutrient levels were not oversaturated. Our results offer insights into specific nutrient targets, species, and, and cyanotoxins to consider in the future to manage Utah Lake.
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Sotton, Benoît. "Mise en évidence des voies de transfert des cyanotoxines dans les lacs péri-alpins et implications dans les réponses physiologiques des poissons exposés." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00808634.
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En dépit de la ré-oligotrophisation de nombreux lacs d'Europe du nord au cours des deux dernières décennies, les développements massifs de cyanobactéries toxiques, telle que Planktothrix rubescens, adaptée aux écosystèmes mésotrophes, sont encore largement observés. Parmi les cyanotoxines produites par cette espèce, les microcystines (MCs) sont les toxines les plus fréquemment rencontrées et sont reconnues comme des molécules perturbatrices de tous les compartiments trophiques des écosystèmes lacustres. Ces blooms toxiques affectent notamment les lacs péri-alpins pour lesquels des risques de contaminations des populations piscicoles exploitées ont été démontrés. Cependant, il existe encore un manque de connaissances important tant concernant les voies de transfert de ces toxines au sein des réseaux trophiques limniques, que leurs effets physiologiques sur les populations de poisson. Dans le cadre de ce travail de thèse, deux modèles de poissons, dont les répartitions spatiales verticales diffèrent (juvéniles de perche et corégones), ont été considérés. Les objectifs principaux ont été traités d'une part au travers d'une approche expérimentale (par gavage) visant à analyser les processus d'accumulation et de détoxification, ainsi que les effets génotoxiques des MCs sur ces deux espèces modèles. Les réponses physiologiques ainsi étudiées ont permis de mettre en évidence que les juvéniles de perche et les corégones sont capables de détoxifier une partie des MCs ingérées, mais cependant des effets génotoxiques sont observés suite à l'exposition des poissons aux MCs. D'autre part, des approches écosystémiques ont permis (1) d'explorer les effets potentiels de la présence du bloom sur la répartition spatiale des poissons (2) d'évaluer les niveaux de contaminations par les MCs pour les deux espèces de poisson en tenant compte de la variabilité saisonnière (3) d'identifier les principaux vecteurs zooplanctoniques de MCs jusqu'aux poissons. Les résultats acquis montrent que les filaments de P. rubescens constituent une ressource alimentaire en période de bloom pour les organismes zooplanctoniques brouteurs et qu'un transfert de MCs est possible jusqu'aux espèces zooplanctoniques prédatrices et in fine jusqu'aux poissons. Nos résultats mettent également en avant que les voies de contaminations ainsi que les intensités de contamination des poissons peuvent varier aussi bien à l'échelle saisonnière que journalière. Ces variations sont expliquées à la fois par les changements de régime alimentaire des poissons, les variations journalières de la production de MCs par P. rubescens, et les abondances et distributions verticales des différentes proies zooplanctoniques. A l'issue de ce travail, la part importante du transfert trophique des MCs jusqu'aux poissons a été vérifiée dans les cas des contaminations chroniques qui caractérisent les conditions de blooms des lacs péri-alpins (concentrations en cyanobactéries et en toxines modérées à fortes au cours de plusieurs mois).
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Chen, Lin. "Removal of cyanotoxins by cyclodextrin complex, titanium dioxide photocatalysis and C₆₀ photocataly." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/2136.
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The presence of cyanotoxins in surface and drinking water is a serious threat to the environment and human health. The most dangerous and widespread cyanotoxins include the microcystin and nodularin families (hepatotoxin), domoic acid (neurotoxin), and cylindrospermopsin (CYN) (hepatotoxin). The primary goal of these studies is to investigate several innovative technologies for the removal and remediation of selected cyanotoxins. The first involves application of cyclodextrins (CDs) as a host to encapsulate cyanotoxins, microcystin, nodularin and domoic acid. Proton NMR was employed for real-time monitoring of the complexation and encapsulation by different sized CDs and specific toxins. The second application involved TiO2 photocatalysis of CYN, a cyanotoxin which was not complexed by CD, TiO 2 photocatalysis leads to the rapid degradation of CYN. The third part of the research project employed functionalized C60 adducts as renewable photoactive materials for the remediation of cyanotoxins. MCLR was used as a model compound and is readily degraded via singlet oxygen mediated photooxidation by C60 photoinitiated processes.
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Waack, Julia. "Uptake and depuration of cyanotoxins in the common blue mussel Mytilus edulis." Thesis, Robert Gordon University, 2017. http://hdl.handle.net/10059/2447.
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Cyanobacteria produce a variety of secondary metabolites which possess amongst others antifungal, antibacterial, and antiviral properties. Being primary producers they are also a vital component within the food web. However, certain strains also produce toxic metabolites such as the hepatotoxins microcystin (MC) and nodularin (NOD). Their toxicity in combination with the increasing global occurrence has resulted in a drinking water guideline limit of 1 μg L-1 being issued by the World Health Organisation (WHO). However, these toxins are not only present in water, but can be accumulated by fish and shellfish. Currently, no regulations regarding cyanotoxin contaminated seafood has been established despite similar toxicity to routinely monitored marine toxins such as domoic acid (DA). To facilitate regular monitoring, a high performance liquid chromatography photo diode array (HPLC-PDA) analysis method for the detection of DA was optimised to enable the simultaneous detection of DA and nine cyanotoxins. This method was then utilised to determine cyanotoxin concentration in laboratory cyanobacteria strains. To assess the accumulation and depuration of cyanotoxins in the common blue mussel Mytilus edulis, three feeding trials were performed. During these, mussels were exposed to two cyanobacteria strains, Nodularia spumigena KAC66, Microcystis aeruginosa PCC 7813, both individually and simultaneously. A rapid dose dependent accumulation of cyanotoxins was observed with maximum concentration of 3.4 -17 μg g-1 ww accumulated by M. edulis, which was followed by a much slower depuration observed. During the final feeding trial, with N. spumigena KAC 66 and M. aeruginosa PCC7813, cyanotoxins were still detectable following 27 days of depuration. Mortality in all studies was 7% or less indicating that most mussels were unaffected by the maximum dose of 480 μg L-1 NOD (feeding study 1), 390 μg L-1 MC (feeding study 2), or 130 μg L-1 total cyanotoxins (feeding trial 3), respectively. Mortality in negative control tanks was lower throughout all three feeding trials ( < 1 - 2.6%). Consumption of a typical portion size (20 mussels) would result in ingestion of cyanotoxins at levels significantly higher than the WHO recommended tolerable daily intake (TDI) of 2.4 μg NOD and/or MCs for a 60 kg adult. This value was exceeded not only during the exposure period (maximum levels 270 - 1370 μg cyanotoxins per 20 mussels), but also at the end of the depuration period 39-600 μg cyanotoxins per 20 mussels. These results illustrated that cyanotoxin monitoring of seafood should be considered not only during, but also following bloom events. In an attempt to investigate the cyanotoxin budget of the experimental system, not only mussels, but cyanobacteria cultures, the tank water, and the mussel faeces were also analysed for their cyanotoxin content. Results showed that large quantities of MCs and NOD were unaccounted for during all exposure trials. The combined effect of cyanotoxin metabolism in M. edulis, biotic and/or abiotic degradation, protein binding, and losses during the extraction and analysis were thought to have contributed to the unaccounted cyanotoxin fraction. Mussel flesh was analysed for the presence of glutathione or cysteine conjugates, however, there was no evidence of their occurrence in the samples tested. Due to these discrepancies in the toxin budget of the system, the introduction of correction factors for the analysis of cyanotoxins in M. edulis was suggested in order to protect the general public.
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Chen, Bingran. "Effects of Chemical Properties of Cyanotoxins on Transport through Granular Activated Carbons." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535374137804276.
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Addico, Gloria Naa Dzama. "Toxic cyanobacteria, cyanotoxins and drinking water production in Ghana: implications to human health." Thesis, University of Hull, 2008. http://hydra.hull.ac.uk/resources/hull:5872.
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The management and control of cyanobacteria and their toxins in drinking water reservoirs and water supplies have engaged the attention of many scientists worldwide due to their negative effects on population health. The cyanotoxin, microcystin, the main focus of this research has been responsible for much documented illness in humans and is the most wildly studied cyanotoxin. The World Health Organization has set a guideline limit of 1 µg/l in drinking water. A number of methodologies have been used in this research. These include the use of an inverted microscope for the identification and quantification of cyanobacteria species after sedimentation in counting chambers. The biomass of picocyanobacteria was determined by epifluorescence microscopy after staining with DAPI. Extraction, purification and concentration of dissolved microcystins were done using the Solid Phase Extraction method. Identification of microcystins was done through comparison with commercial standards and their characteristic UV- spectra, and quantified by extrapolations of HPLC peak areas at 238 nin to a linear calibration curve for microcystin-LR standard. Nutrients (N0₂-N, N0₃-N and P0₃-P) in reservoirs in Ghana were analysed using the American Public Health Association standard methods. The results which are the first of their kind from Ghana, and for most part in West Africa, highlight that the water treatment processing currently in place is not effective in removing cyanobacteria cells from the final drinking water. Positive correlations were obtained between cyanobacteria biomass and nutrients concentrations in the reservoirs. Fifteen new cyanobacteria species were identified for the first time in Ghana of which Cyanogranisferrugineais reported for the first time in tropical waters. Four known microcystin variants -1R, -RR, - LF and -YR in both dissolved and intracellular samples were identified in four drinking water reservoirs. The study concludes that, the presence and dominance of potentially toxic small sized cyanobacteria such as Aphanocapsa nubilum, Cyanogranis ferruginea, Geitlerinema unigranulatum and other toxic cyanobacteria species like Cylindrospermopsis raciborskii, Planktothrix agardhii and Microcystis spp in the Weija, Kpong, Barekese and the Owabi reservoirs all with basic conventional drinking water treatment facilities, shown to be ineffective in removing cyanobacteria and their toxins, present a potential risk to human health through exposure to cyanotoxins such as microcystins and cylindrospermopsin. Even though the concentrations of dissolved microcystins obtained in the reservoirs and drinking water supplies were lower than the WHO limit, there is potentially a risk to public health and ongoing monitoring would be a good idea.
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Jagani, Neelam V. "Evaluating Home Point-of-Use Reverse Osmosis Membrane Systems for Removal of Cyanotoxins." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1524844338053604.
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Sonobe, Henrique Gamon. "Remoção de microcistina por filtros de carvão ativado granular: aplicação de modelos matemáticos para obtenção de parâmetros de dimensionamento." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-19062018-165550/.
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Uma das principais preocupações em relação à crescente ocorrência de cianobactérias em sistemas aquáticos está relacionada à capacidade de algumas espécies em produzir e liberar toxinas, entre elas as microcistinas, que podem afetar a saúde humana. O processo convencional de tratamento de água é muitas vezes insuficiente para remover a toxina dissolvida na água. Entre as tecnologias que podem ser utilizadas para removê-la, estão os filtros de carvão ativado granular (CAG). Essa pesquisa se dedicou ao aprofundamento do conhecimento sobre o desempenho de colunas de CAG quando operadas para remover microcistina de águas de abastecimento. A água de estudo foi composta por água de poço artesiano contaminada por extrato de microcistina (MC), produzindo soluções com concentrações iniciais de MC-LR que variaram entre 14 µg/L e 92 µg/L. Em ensaios de adsorção em colunas de leito fixo, sob regime contínuo, foram avaliados três tipos de CAG, de origens diferentes, sendo um vegetal (CAG-Ccoco) e dois minerais (CAG-Hulha e CAG-Linhito). A partir das curvas de ruptura dos ensaios, foram avaliadas as remoções de microcistina e a capacidade de adsorção desse poluente pelos carvões ativados. Ao ajustar modelos matemáticos (Bohart-Adams, Thomas e Yoon-Nelson) às curvas de ruptura, foi possível obter informações sobre a capacidade de adsorção dos carvões. Os resultados mostraram que o CAG-Linhito possui melhor capacidade de adsorção (164 µg/g), seguido pelo CAG-Ccoco (79 µg/g) e, por último, GAG-Hulha (62 µg/g). A maior capacidade de adsorção de microcistina do CAG-Linhito foi atribuída ao maior volume de mesoporos (0,53 cm³/g) presente em sua estrutura (CAG-Ccoco = 0,05 cm³/g e CAG-Hulha = 0,06 cm³/g). A adsorção de microcistina por colunas de CAG se mostrou eficiente para remoção do poluente do meio líquido, em especial com a utilização do CAG-Linhito.One of the main concerns about the increasing occurrence of cyanobacteria in aquatic systems is related to the ability of some species to produce and release toxins, including microcystins, which may affect human health. The conventional water treatment process is often insufficient to remove the toxin dissolved in the water. Among the technologies that can be used to remove microcystins are granular activated carbon (GAC) filters. This research focused on knowledge enhancement about the performance of GAC columns when operated to remove microcystin from supply water. The study water was composed of artesian well water contaminated by microcystin (MC) extract, producing solutions with initial concentrations of MC-LR that varied between 14 µg / L and 92 µg / L. In adsorption tests on fixed bed columns, under continuos regime, three types of GAC were evaluated, from different sources, being one vegetal (GAC-Ccoco) and two minerals (GAC-Hulha and GAC-Linhito). From the breakthrough curves, the microcystin removals and the adsorption capacity of this pollutant by activated carbons were evaluated. By adjusting mathematical models (Bohart-Adams, Thomas and Yoon-Nelson) to the breakthrough curves, it was possible to obtain information about the adsorption capacity of the GAC. The results showed that GAC-Linhito had better adsorption capacity (164 µg/g), followed by GAC-Ccoco (79 µg/g) and, finally, GAC-Hulha (62 µg/g). The highest adsorption capacity of GAC-Linhito was attributed to the higher volume of mesopores (0.53 cm³/g) present in its structure (GAC-Ccoco = 0.05 cm³/g GAC-Coal = 0.06 cm³/g). The adsorption of microcystin by GAC columns proved to be efficient for removal of the pollutant from the liquid medium, especially with the use of GAC-Linhito.
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Abesh, Bidisha Faruque. "Modeling and Understanding Groundwater Contamination Caused by Cyanotoxins from Harmful Algal Blooms in Lake Erie." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1562953927561716.
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Marion, Jason W. "Protecting Public Health at Inland Ohio Beaches: Development of Recreational Water Quality Indicators Predictive of Microbial and Microcystin Exposure." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313588302.
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Reveillon, Damien. "BMAA et cyanotoxines : microalgues productrices et niveaux d'accumulation dans les organismes marins." Nantes, 2015. https://archive.bu.univ-nantes.fr/pollux/show/show?id=bc18728b-24b7-4a54-8f95-7f0a0e48042e.
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La BMAA (β-N-méthylamino-L-alanine) est un acide aminé non protéique neurotoxique associé à la sclérose latérale amyotrophique dont la détection souffre d’une controverse analytique remettant en question sa production par l’ensemble des cyanobactéries. Notre premier objectif était donc de développer une méthode d’analyse de la BMAA et ses isomères, très sélective, par chromatographie HILIC couplée à la spectrométrie de masse. Nous avons ensuite cultivé et criblé une cinquantaine d’espèces de microalgues (e. G. Cyanobactéries, diatomées). Contrairement au DAB, un isomère largement retrouvé, la BMAA a été découverte seulement dans 5 souches de diatomées, remettant en question sa qualification de cyanotoxine. En parallèle, nous avons évalué la présence de BMAA sur les côtes françaises. Elle a été détectée dans différents compartiments de l’écosystème de Thau (i. E. Plancton, biofilm et moule) nous amenant à émettre l’hypothèse d’une bioaccumulation, avec les diatomées comme source de BMAA. De plus, tous les mollusques collectés mensuellement dans 10 zones conchylicoles en 2013 contiennent la BMAA et ses isomères, suggérant qu’ils sont continuellement présents dans les bivalves alors que le mécanisme de bioaccumulation n’est pas connu. Une première expérience de contamination au laboratoire révèle un possible lien, à confirmer, entre l’accumulation de BMAA dans les moules et leur consommation d’une diatomée productrice de BMAA. Enfin, la procédure d’analyse multi-cyanotoxines développée a permis la détection de cylindrospermopsine dans le biofilms de coquillages de Thau, suggérant l’intérêt de poursuivre les travaux quant à la problématique « cyanotoxines » dans l’environnement marinBMAA (β-N-methylamino-L-alanine) is a non proteinogenic neurotoxic amino acid that has been associated with amyotrophic lateral sclerosis. Its analytical detection is widely debated thus the global production of BMAA by cyanobacteria is questioned. We first aimed at developing an analytical method allowing for highly selective identification of BMAA and isomers, using HILIC chromatography coupled to mass spectrometry. Then, we have cultivated and analyzed more than 50 microalgae (e. G. Cyanobacteria, diatoms). Unlike DAB, one of its natural isomer, BMAA was only reported in five diatom species and cannot be accounted as a cyanotoxin anymore. In parallel, we have evaluated the presence of BMAA on the three French coasts. The presence of BMAA in different compartments of the Thau lagoon food web (i. E. Plankton, biofilm and mussel) led us to hypothesize a bioaccumulation pathway with diatom as a source of BMAA. Moreover, BMAA and DAB were both detected in all mollusk samples collected once a month in 2013 from 10 French shellfish production areas. While they were continuously detected, the bioaccumulation mechanism of these amino acids is unknown. Therefore, we tried to contaminate blue mussels in controlled conditions with a BMAA-producing diatom. Results of this first attempt may suggest a link between the accumulation of BMAA in mussel and their consumption of the diatom strain. Finally, the multi-cyanotoxins analytical procedure that we developed allowed us to detect cylindrospermopsin in biofilms collected from mussels of Thau lagoon, calling for extended research efforts on cyanotoxins-derived issue in the marine environment
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Welgamage, Don Aakash Channa Dharshan. "An investigation into the biodegradation of peptide cyanotoxins (microcystins and nodularin) by novel gram-positive bacteria." Thesis, Robert Gordon University, 2012. http://hdl.handle.net/10059/738.
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Cyanobacterial secondary metabolites, microcystins (MC) and nodularin (NOD) have become common contaminants in most aquatic ecosystems over recent years presenting a hazard to animal and human health. Unfortunately, these chemically diverse peptide hepatotoxins remain a challenge to most conventional water treatments due to their stable cyclic structures. Over recent years, bioremediation of MC and NOD has become one of the most exciting areas that holds promise for a successful and cost effective solution for water treatment process. The current work presents the biodegradation of MCs and NOD by bacterial isolates from three different bacteria genus Arthrobacter, Brevibacterium and Rhodococcus belonging to Actinobacteria. A total of five isolates representing the three genera have demonstrated an overall metabolism of MC-LR, -LF, -LY, -LW, -RR and NOD in a Biolog MT2 assay. Subsequently, these bacteria were reported to degrade the range of toxins in a separate batch experiment. The bacterial degradation rate of the above cyanobacterial peptides were found to decrease with the multiple subculturing of the bacteria. However, a rapid degradation was discovered when the bacteria were re-exposed to MC or other prokaryotic peptides demonstrating an inducible bacterial biodegradation. Utilising latest molecular biology techniques, the gene responsible for production of MC degrading enzymes was successfully elucidated and its activity was evaluated. Analysis of the degradation products of MC-LR revealed a glutathione conjugate detoxification mechanism involved during the degradation of MC-LR by Rhodococcus sp. (C1). A novel MC degradation pathway was proposed. Further studies were suggested to fully characterise the degradation pathway and to evaluate the MC detoxification mechanism in bacteria.
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Kelley, Thomas M. "Using Rapid Small Scale Column Testing to Evaluate Granular Activated Carbon Adsorption of Cyanotoxins from Drinking Water." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin150514901618082.
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Conradie, Karin Ronel. "Molecular assessment of the occurrence of toxic cyanobacteria and cyanotoxins in South African impoundments / by Karin Ronel Conradie." Thesis, North-West University, 2008. http://hdl.handle.net/10394/2120.
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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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Zeller, Perrine. "Cyanotoxines et barrière intestinale humaine : Étude comparée de l'absorption et de la toxicité de deux variants de microcystine sur le modèle cellulaire Caco-2." Rennes, Agrocampus Ouest, 2011. http://www.theses.fr/2011NSARI062.
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Les microcystines (MCs), hépatotoxines produites par des cyanobactéries d‟eau douce, sont incriminées dans des intoxications humaines et animales. L‟ingestion est leur principale voie d‟exposition chez l‟homme. Parmi les quelques 90 variants décrits, la MC-LR constitue le variant le plus toxique et le mieux connu sur lequel est fondé l'évaluation du risque associé aux MCs. Afin de mieux caractériser le danger pour l‟homme par ingestion, nous avons choisi d‟étudier et de comparer l‟absorption et la toxicité de deux variants, la MC-LR et la MC-RR, sur un modèle cellulaire intestinal humain, les Caco-2. Ces deux variants, de structure quasi identique, sont connus pour leur différence de toxicité aiguë. Nous avons montré que, contrairement aux cellules hépatiques, les Caco-2 absorbent les deux variants de manière similaire. De plus, nos travaux suggèrent l‟existence d‟un efflux actif de la MC-LR et de la MC-RR par les Caco-2. Enfin, une étude à l‟échelle pangénomique a permis de mettre en évidence des différences de réponses cellulaires, avec des atteintes plus marquées de la MC-LR sur la réponse au stress oxydant, la régulation du cycle cellulaire, le stress du réticulum endoplasmique et la dégradation des protéines. Ainsi, les mécanismes de toxicité mis en jeu par les deux variants semblent diverger. Nos travaux soulignent donc la nécessité d‟obtenir de données complémentaires sur d‟autresvariants que la MC-LR pour affiner l‟évaluation du risque associé aux MCsMicrocystins (MCs), produced by freshwater cyanobacteria, are hepatotoxins involved in numerous cases of human and animal intoxications. Ingestion is the major pathway of human exposure. Among almost 90 variants described, MC-LR is the most frequent and the most toxic variant on which MCs risk assessment has been set up. In order to characterize the hazard for human ingestion, we chose to study and compare absorption and toxicity of two variant, MC-LR and MC-RR, on a human intestinal cell line (Caco-2). The two variants, even with are known for their difference in acute toxicity. . We showed that, on the contrary to hepatocytes, both variants were uptaken equally by Caco-2 cells. Moreover, our results suggest a active efflux of MCs from Caco-2 cells. Finally, comparing MC-LR and MC-RR toxicity at a pangenomic scale elicited dissimilarity in cell responses with a larger effect of MC-LR including on oxidative stress, cell cycle regulation, stress of the endoplasmic reticulum and protein degradation. So, differences on the mechanism of toxicity between both variants are suggested. Thereby, our work highlights the need of toxicity studies on other variants than MC-LR in order to improve MCs risk assessment