145 research outputs found

    IMPACTS OF WASTEWATER EFFLUENTS AND SEASONAL TRENDS ON LEVELS OF EMERGING CONTAMINANTS IN TWO COLD-REGION RIVERS

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    Emerging contaminants such as pharmaceutical drugs have been detected in waters across the globe and are of concern for human and aquatic ecosystems health. Most pharmaceuticals are found at trace concentrations, but the continuous use and potential accumulation of some of these compounds can potentially lead to effects in aquatic organisms. The principal aim of this research was to enhance our understanding of the environmental risks associated with pharmaceuticals as one group of emerging contaminants. Many pharmaceuticals are ionizable organic chemicals (IOCs), which makes their environmental and toxicological behavior particularly challenging to predict due to their partitioning mechanism which is useful to estimate the distribution of the chemical. Therefore, the objective of this thesis was to evaluate the hypothesis that uptake and effects of IOCs in aquatic organisms are influenced by the interaction between environmental, physicochemical, and biological factors. To this end, first, field studies were conducted during spring, summer, and fall of 2021 on water (diffusive gradient in thin film and conventional grab) and sediments at four locations including upstream and downstream of the wastewater treatment plants (WWTPs) of the cities of Saskatoon and Regina in the South Saskatchewan River and Wascana Creek, Saskatchewan, Canada, respectively. Second, seven representative antipsychotic pharmaceuticals were measured in water, sediment, and fish samples up- and downstream of the City of Regina WWTP. Data collected from this research effort indicate contamination with antipsychotic pharmaceuticals, with the potential to adversely impact exposed organisms. Third, non-target chemical analysis was conducted in water, sediments, and fish samples, at the two locations in Wascana Creek and throughout the three seasons. Data collected from non-target analysis indicated that pharmaceuticals, rubber components and personal care products were the priority pollutants in all the matrices and their transcriptomics changes were also supported by the qPCR analysis. Finally, transcripts of several genes of interest were determined in brain and liver samples from in fathead minnow (Pimephales promelas) exposed to the wastewater effluents in Wascana Creek during summer and fall in 2021, using a qPCR gene expression array (the EcoToxChips). The integrative approach used in this study, strongly supports the need to combine chemical analysis with transcriptomics-based approaches as useful tools for assessing of complex mixtures of contaminants in wastewater discharges and their effects in aquatic organisms. This research provides a better understanding of the risks that pharmaceuticals may pose to aquatic organisms under varying environmental conditions and thereby aid in better protecting aquatic ecosystems in the future

    Atenuación de contaminantes de preocupación emergente en filtros verdes. Identificación de productos de transformación

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    La presente Tesis Doctoral se centra en evaluar la eficacia de filtros verdes (FVs) como tratamiento de aguas residuales en la atenuación de Contaminantes de Preocupación Emergente (CPEs). Los FVs consisten en una plantación forestal de alta densidad que se riega con aguas residuales pretratadas. Es un sistema de tratamiento o solución basada en la naturaleza (SBN) en la que se aprovechan los procesos naturales (principalmente (bio)degradación, adsorción y absorción) para reducir la contaminación presente en el agua. Esta técnica aporta grandes beneficios medioambientales, como la recuperación de nutrientes, la generación de biomasa y la recarga de acuíferos, pero se debe prestar especial atención a la posible introducción de contaminantes en el medio ambiente, los cuales podrían alcanzar las aguas subterráneas e incluso viajar grandes distancias inalterados. Este trabajo se encuadra en el marco del proyecto FILVER+ (CTM2016-79211-C2-1-R) cuyo objetivo era aumentar la eficiencia de un FV piloto en la mejora de la calidad de las aguas lixiviadas, maximizando la eliminación de materia orgánica, nutrientes, CPEs y microorganismos patógenos mediante la adición de enmiendas al suelo. Una mayor eficiencia en la atenuación de contaminantes no solo permitirá que el agua tratada tenga la calidad suficiente como para incrementar los recursos hídricos subterráneos de la zona, sino que también permitirá reducir la superficie del FV, aproximándose de esta manera algo más al concepto de tecnología intensiva, siempre sin dejar de regirse por los principios de las SBN. En concreto, este trabajo estudia el comportamiento de CPEs y, además, la aparición de productos de transformación y/o metabolitos (en adelante PTs) a través del suelo natural y enmendado. Con el fin de cumplir los requisitos para la presentación de la Tesis Doctoral en el formato compendio de artículos, esta memoria se ha estructurado en varios capítulos. Se ha optado por mantener el formato de cada artículo científico traducido al castellano. También se ha incluido en el texto el material suplementario, así como algunos datos adicionales para facilitar la lectura de esta memoria (las tablas y figuras conservan la notación inglesa de puntos para los decimales). El capítulo I, consta de una introducción general sobre el recurso hídrico y su necesidad de reutilización, así como de la contaminación que sufre, principalmente por CPEs, junto a las vías de entrada de los mismos. También se abordan los principales tratamientos de las aguas residuales y las técnicas de análisis para la determinación de CPEs en los diferentes tipos de matrices ambientales. Se incluye además un apartado sobre la legislación aplicada a la contaminación de las aguas, su análisis y reutilización. Por último, se recogen los objetivos de la Tesis Doctoral. En el capítulo II, se describen los diseños experimentales realizados durante la investigación: 1) un ensayo a “escala de campo” empleando un FV piloto para el tratamiento de aguas residuales urbanas y, 2) un ensayo a “escala de laboratorio” empleando columnas de infiltración para simular la operación en un FV. En el capítulo III, se desarrolla y valida una metodología analítica para la determinación de 40 CPEs, seleccionados por una serie de criterios científico-técnicos, en muestras de aguas y suelo procedentes del FV piloto, mediante Cromatografía de Líquidos acoplada a vi Espectrometría de Masas en tándem (LC-MS/MS) con analizador de triple cuadrupolo (QqQ). El método se basa en un pretratamiento de las muestras mediante extracción en fase sólida (SPE) y, en el caso de suelo, una extracción sólido-líquido con disolvente. La aplicabilidad del método se demuestra analizando las primeras muestras de aguas y suelos obtenidas del FV piloto. El capítulo IV, se describe el ensayo realizado a “escala de laboratorio” en tres columnas de infiltración de suelo sin y con enmiendas (suelo natural procedente del FV piloto y el mismo suelo enmendado con astillas de madera o con biochar) regadas con agua residual sintética, que incluye 11 CPEs seleccionados de entre los 40 CPEs anteriores (capítulo III). En este estudio se evalúa: i) la atenuación de dichos CPEs (análisis dirigido) y ii) la formación de PTs desconocidos (análisis no dirigido). El análisis dirigido consistió en la aplicación del método de análisis desarrollado en el capítulo III para obtener las concentraciones de los 11 CPEs y con ello realizar un balance total de masas que permitió evaluar su atenuación en las tres columnas. La estrategia no dirigida consistió en un análisis de las muestras empleando la Cromatografía de Líquidos acoplada a Espectrometría de Masas en tándem de Alta Resolución (LC-HRMS) junto a la utilización de herramientas estadísticas para el tratamiento de los datos obtenidos. Esta estrategia permitió encontrar las diferencias entre grupos de muestras establecidos, sin tener conocimiento previo de los PTs en que debe centrarse el estudio. Con objeto de incrementar aún más la aplicabilidad del análisis no dirigido, fue imprescindible llevar a cabo un minucioso diseño de las etapas del estudio para detectar el mayor número de compuestos. Además, hay que considerar la complejidad de este tipo de análisis debido a que los compuestos presentan propiedades fisicoquímicas muy diversas. Ello unido a la gran variabilidad de las condiciones medioambientales junto a las bajas concentraciones en las que se espera encontrar los PTs en muestras reales, fue el motivo de realizar el estudio de la búsqueda de PTs generados desconocidos a escala de laboratorio en lugar de a escala de campo. El capítulo V comprende los resultados de la monitorización de los CPEs seleccionados, en muestras reales del FV piloto recogidas durante todo el periodo de duración del proyecto (casi cuatro años). Estos resultados han permitido la evaluación de la capacidad del FV en la atenuación de dichos compuestos en diferentes condiciones de operación, diferenciadas principalmente en el uso de enmienda de astillas en dos configuraciones distintas y la modificación del tipo y la frecuencia de riego del FV. En concreto se probó riego superficial por inundación de los surcos y por goteo, y frecuencia semanal y diaria. Aunque limitadas, las observaciones descritas hasta ahora en la bibliografía sugieren que, aunque las SBN, y más concretamente los FVs, representan tecnologías prometedoras para la eliminación de CPEs, surgen algunas preocupaciones sobre la lixiviación de compuestos más persistentes y móviles. Por ello, en este capítulo se presentan los resultados obtenidos tras actuar sobre dos parámetros considerados cruciales para conseguir un rendimiento robusto del tratamiento en los FVs: el patrón y método de riego, y la "reactividad" del suelo. Así, se investigaron específicamente los efectos del manejo del agua de riego y la incorporación de enmiendas en la capacidad de atenuación de los CPEs seleccionados. Además, también se evalúan los impactos potenciales sobre los recursos hídricos subterráneos recordando que los compartimentos sobre y bajo tierra representan un vii conjunto indivisible. Este estudio hace frente a la escasez de datos proporcionando una investigación que abarca casi cuatro años durante los cuales se han monitorizado múltiples matrices y compartimentos medioambientales. Finalmente, en el capítulo VI se realiza una discusión general en la que se expone el hilo conductor que enlaza las investigaciones realizadas y los principales resultados obtenidos. Y, por último, el capítulo VII recoge las conclusiones obtenidas durante los trabajos desarrollados que dan respuesta a los objetivos propuestos. Tras la realización de los trabajos presentados en esta tesis, se incluyen una serie de recomendaciones que podrían estudiarse en el futuro para completar el conocimiento sobre la atenuación de CPEs empleando FVs y que se exponen al final del capítulo VII

    Physiologically Based Pharmacokinetic Modeling to Describe the CYP2D6 Activity Score-Dependent Metabolism of Paroxetine, Atomoxetine and Risperidone

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    The cytochrome P450 2D6 (CYP2D6) genotype is the single most important determinant of CYP2D6 activity as well as interindividual and interpopulation variability in CYP2D6 activity. Here, the CYP2D6 activity score provides an established tool to categorize the large number of CYP2D6 alleles by activity and facilitates the process of genotype-to-phenotype translation. Compared to the broad traditional phenotype categories, the CYP2D6 activity score additionally serves as a superior scale of CYP2D6 activity due to its finer graduation. Physiologically based pharmacokinetic (PBPK) models have been successfully used to describe and predict the activity score-dependent metabolism of CYP2D6 substrates. This study aimed to describe CYP2D6 drug–gene interactions (DGIs) of important CYP2D6 substrates paroxetine, atomoxetine and risperidone by developing a substrate-independent approach to model their activity score-dependent metabolism. The models were developed in PK-Sim®, using a total of 57 plasma concentration–time profiles, and showed good performance, especially in DGI scenarios where 10/12, 5/5 and 7/7 of DGI AUClast ratios and 9/12, 5/5 and 7/7 of DGI Cmax ratios were within the prediction success limits. Finally, the models were used to predict their compound’s exposure for different CYP2D6 activity scores during steady state. Here, predicted DGI AUCss ratios were 3.4, 13.6 and 2.0 (poor metabolizers; activity score = 0) and 0.2, 0.5 and 0.95 (ultrarapid metabolizers; activity score = 3) for paroxetine, atomoxetine and risperidone active moiety (risperidone + 9-hydroxyrisperidone), respectively

    A prebiotic basis for ATP as the universal energy currency

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    ATP is universally conserved as the principal energy currency in cells, driving metabolism through phosphorylation and condensation reactions. Such deep conservation suggests that ATP arose at an early stage of biochemical evolution. Yet purine synthesis requires 6 phosphorylation steps linked to ATP hydrolysis. This autocatalytic requirement for ATP to synthesize ATP implies the need for an earlier prebiotic ATP equivalent, which could drive protometabolism before purine synthesis. Why this early phosphorylating agent was replaced, and specifically with ATP rather than other nucleoside triphosphates, remains a mystery. Here, we show that the deep conservation of ATP might reflect its prebiotic chemistry in relation to another universally conserved intermediate, acetyl phosphate (AcP), which bridges between thioester and phosphate metabolism by linking acetyl CoA to the substrate-level phosphorylation of ADP. We confirm earlier results showing that AcP can phosphorylate ADP to ATP at nearly 20% yield in water in the presence of Fe3+ ions. We then show that Fe3+ and AcP are surprisingly favoured. A wide range of prebiotically relevant ions and minerals failed to catalyse ADP phosphorylation. From a panel of prebiotic phosphorylating agents, only AcP, and to a lesser extent carbamoyl phosphate, showed any significant phosphorylating potential. Critically, AcP did not phosphorylate any other nucleoside diphosphate. We use these data, reaction kinetics, and molecular dynamic simulations to infer a possible mechanism. Our findings might suggest that the reason ATP is universally conserved across life is that its formation is chemically favoured in aqueous solution under mild prebiotic conditions

    Effect of composting and amendment with biochar and woodchips on the fate and leachability of pharmaceuticals in biosolids destined for land application

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    Land application of biosolids can improve soil fertility and enhance crop production. However, the occurrence and persistence of pharmaceutical compounds in the biosolids may result in leaching of these contaminants to surface water and groundwater, causing environmental contamination. This study evaluated the effectiveness of two organic amendments [biochar (BC) and woodchips (WC)] for reducing the concentration and leachability (mobility) of four pharmaceuticals in biosolids derived from wastewater treatment plants in southern Ontario, Canada. The effect of 360-d composting on fate and leachabilities of target pharmaceuticals in biosolid mixtures was also investigated. Composting decreased total and leachable concentrations of pharmaceuticals in unamended and BC- and WC-amended biosolids to various degrees, from 10% up to 99% depending on the compound. Blending BC or WC into the biosolids greatly increased the removal rates of the target pharmaceuticals, while simultaneously decreasing their half-lives (t0.5), compared to unamended biosolids. The t0.5 of contaminants in this study followed the order: carbamazepine (304–3053 d) > gemfibrozil (42.3–92.4 d) > naproxen (15.3–104 d) > ibuprofen (12.5–19.0 d). Amendment with BC and(or) WC significantly reduced the leachability of carbamazepine, ibuprofen, and gemfibrozil to variable extents, but significantly enhanced the leachability of naproxen, compared to unamended biosolids (P < 0.05). Biochar and WC exhibited different (positive or negative) effects on the leachability of individual pharmaceuticals. Significantly lower concentrations of total and(or) leachable (mobile) pharmaceuticals were observed in amended biosolids than unamended biosolids (P < 0.05). Biochar and WC are effective amendments that can reduce the environmental impact of biosolid land applications with respect to pharmaceutical contamination.Natural Sciences and Engineering Research Council of Canada || Natural Resources Canada

    Universal energy currencies at the origin of life

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    There is little agreement on how life might have started on Earth. Following life as a guide, phylogenetic and comparative biochemical studies point to an autotrophic origin, with complexity accruing over time. In modern metabolism, the universal energy currency is adenosine triphosphate (ATP), which not only drives metabolism through phosphorylation and condensation reactions but is also key for the synthesis of the informational molecules RNA, DNA, and proteins. Such deep conservation suggests an early origin of ATP, before the emergence of genes or genetically-encoded macromolecular machines such as the ATPase. This thesis explores the plausibility of an early emergence of ATP and the role it might have had at the origin of life. I first confirm earlier work showing moderate (15-20%) ATP yield from the non-enzymatic phosphorylation of ADP by acetyl phosphate (AcP), before systematically exploring the prebiotic context for this synthesis. AcP is a universally conserved intermediate between acetyl-CoA and ATP, bridging between thioester and phosphate metabolism. I show that it is possible to form moderate yields of ATP in a variety of aqueous environments. The combination of AcP and the catalyst Fe³⁺ is surprisingly favoured. No other prebiotically relevant metal ion, mineral, and phosphorylating agent tested here favoured ADP phosphorylation. Nor could AcP phosphorylate other nucleoside diphosphates to the triphosphates. I demonstrate a reaction mechanism that implicates the N7 and the N6 amino group on the adenine ring in the Fe³⁺-catalysed phosphorylation of ADP, implying a deep significance of the adenine base. Finally, I explore how ATP might have facilitated condensation reactions to generate nucleotide and peptide polymers in an aqueous environment, using life as a guide. These efforts met with limited success, confirming that condensation reactions are not facile in water. Nonetheless, my findings overall support the approach of taking life as a guide to study the origin of life

    Fusion of human monocarboxylate transporter 1 with basigin and expression in S. cerevisiae: Is basigin more than a chaperone?

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    Lactate is a key metabolite in human cells. A regulated transport across membranes is vital for cellular function while deregulated transport is a hallmark of cancer. In tumor cells, glycolysis as the main route for ATP synthesis even in the presence of oxygen (Warburg effect) demands rapid lactate clearance to avoid acidification. Oxygenic cancer cells, in turn, rely on an efficient retrieval of extracellular lactate to fuel the citric acid cycle (reverse Warburg effect). To maintain an active interchange between cells, four monocarboxylate transporters (MCT1−4) manage bi-directional, proton-coupled transport across plasma membranes. For its translocation to the plasma membrane, MCT1 demands chaperoning by a member of the immunoglobulin superfamily, namely basigin. Both proteins remain complexed at the plasma membrane. Although frequently suggested, a direct effect of the chaperone on MCT1-mediated transport is not resolvable in commonly used expression systems. In this study, MCT1 expression in S. cerevisiae Δjen1 Δady2 profited from a basigin-independent translocation in a system with zero background from endogenous monocarboxylate transporters or basigin homologs. The molecular fusion with truncated basigin constructs revealed an effect on transmembrane L-lactate distribution at the domain level. In zero-trans influx experiments using 14C-labeled substrate, the presence of basigin’s extracellular Ig-I domain permitted a 4.5-fold intracellular L-lactate accumulation in the transport equilibrium. At near-neutral pH, cytosolic L-lactate concentrations greatly exceeded those provided with the buffer. The absence of the basigin Ig-I domain due to truncation or misfolding reversed this effect. The identification of patches of positive and negative surface potentials and evidence from charge-resolving point mutations indicated an electrostatic attraction of L-lactate anions and protons. This thesis deduces a substrate harvesting function of basigin that creates a “microenvironment” of locally increased concentrations and drives L-lactate influx according to Le Chatelier’s principle. This influx was physiologically relevant and promoted cell growth on L-lactate medium. According to classical and reverse Warburg effects, highly adapted tumor cells require a fine-tuned transmembrane L-lactate distribution and basigin might be an important determinant. Hereof, MCTs are promising targets in the anti-tumor therapy. The basigin-MCT1 fusion set-up from this study further revealed two known MCT1 inhibitors, AZD3965 and p-chloromercuribenzene sulfonate (pCMBS), as direct and basigin-independent modifiers. Cys159 in the transporter cavity was revealed as selectively targetable by pCMBS leading to a complete transport inhibition. Smaller cysteine-modifiers had a less prominent effect and lacked site-specificity. Cys159 is proposed to constitute a hinge region of the alternating access transporter and a wedge-like modification locks MCT1 in the outward open conformation. This reveals a target region for inhibitor design and in the future, Cys159 might serve as a natural anchor to introduce distinct labels and report on physicochemical modalities in a most critical part of the transporter

    Study of Controlling Secondary Building Units of Metal-organic Frameworks

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    Department of ChemistryA class of metal-organic frameworks (MOFs) were constructed by polynuclear metal clusters (secondary building unitshereinafter, SBUs) and their coordination with organic linkers (i.e., ligands). Such MOFs have been widely used in the various applications fields such as gas storage and separation, chemical sensing, and catalysis due to their stable structures and possibility of having a diverse set of functions. To make such MOFs have specific functions applicable to the application fields, we need to synthesize MOFs with specific crystal structures by controlling the two determinants of the crystal structures ??? the SBUs per se and/or their coordination with ligands. In this thesis, we reported the two research on controlling SBUs of MOFs. One research deals with the transformation of SBUs in synthesizing a rarely reported ndc-based Zn MOF. The other research deals with the formation of SBUs in synthesizing bdc-based Zn MOFs. For each research, we identified the set of parameters that facilitate the synthesis of MOFs with specific SBUs. First, we conducted the transformation of SBUs in synthesizing a rarely reported ndc-based Zn MOF. We transformed specific MOFs ???Zn MOFs having four handed paddlewheel SBUs linked by N-donor pillars ??? into another MOF ??? MOF having 7-coordinated Zn4O(COO)7 SBUs. We found that the two parameters ??? the presence of Zn+-O- in solution and the basicity of ligands ??? affect the transformation of SBUs. First, the presence of Zn+-O- in solution facilitates the transformation of SBUs. We conducted the transformation of the two same Zn-MOFs in two different solutions ??? one solution contains Zn+-O- in solution and the other solution does not contain Zn+-O- in solution. We found that the Zn-MOF in a solution containing Zn+-O- were transformed into the MOF that we want to obtain (i.e., MOF having 7-coordinated Zn4O(COO)7 SBUs) but the Zn-MOF in the other solution did not. Second, low basicity of ligands facilitates the solid-state transformation. We synthesized three Zn-MOFs by making each of them have different basicity of ligands and found that a Zn-MOF with a low level of basicity of ligands was successfully transformed into the other MOF that we want to obtain (i.e., a MOF having 7-coordinated Zn4O(COO)7 SBUs). We also conducted the formation of diverse SBUs in synthesizing bdc-based Zn MOFs (bdc = benzene-1,4-dicarboxylate). We found that the two parameters ??? the reaction temperature and the molar ratio of precursors (i.e., metal precursors and ligand precursors)??? influence the determination of the SBUs of the bdc-based Zn-MOFs .We found that at lower temperature, a Zn-MOF having Zn3(COO)6 SBUs was successfully formed. Secondly, we found that molar ratio of metal precursors to ligand precursors affects the formation of bdc-based Zn-MOFs. At the molar ratio of Zn(NO3)2??6H2O : H2bdc = 1 : 2, a Zn-MOF having Zn3(COO)6 SBU, to which two terminal DMF solvents are coordinated, was obtained. At the molar ratio of Zn(NO3)2??6H2O : H2bdc = 1 : 4, the other Zn-MOF having Zn3(COO)6(COOH)2 SBU (Not surely determined), which is linked by bdc pillars, was obtained. After studying how to synthesize MOFs, we further explored the possibility of using the MOF that is synthesized by the above-mentioned transformation of SBUs (i.e., 7C-MOF) for CO2 cycloaddition. 7C-MOF has been rarely reported in the academic field, so exploring the characteristics of this MOF that can be applicable into the ???real??? world may contribute to expanding the usage of 7C-MOF. We analyzed 7C-MOF using CO2 sorption isotherm and found that 7C-MOF is capable of adsorbing CO2 molecules. This is because 7C-MOF is an anionic framework and has cation complex [Zn(DMF)6]2+ in its pores. Thus, we expected that 7C-MOF can act as a Lewis catalyst for CO2 cycloaddition. By analyzing product yields (100[mole of cyclic carbonate] / [mole of cyclic carbonate and epoxide]) using H-nuclear magnetic resonance spectroscopy, we found that 7C-MOF can act as a Lewis acid catalyst which facilitates CO2 cycloaddition.ope

    Implantable Nanofluidic Membrane and Smart Electronic System for Drug Release Control

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