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<p>Predmet ovog istaživanja&nbsp; bio je ispitivanje&nbsp;uticaja jona tri te&scaron;ka metala (Ni²⁺, Cu^2+&nbsp;i Cd²⁺)&nbsp;u dve toksične koncentracije u zemlji&scaron;tu na&nbsp;fiziolo&scaron;ke i biohemijske karakteristike&nbsp;<br />odabranih klonova topola, M1, B229 i Pe 19/66.&nbsp;Ispitan je i potencijal odabranih klonova topola&nbsp;da vr&scaron;e fitoekstrakciju-akumulaciju te&scaron;kih&nbsp;metala iz zemlji&scaron;ta u svoje nadzemne delove &scaron;to&nbsp;dovodi&nbsp; do dugoročnog uklanjanja ovih&nbsp;perzistentnih polutanata iz životne sredine.&nbsp;Takođe, ispitan je uticaj te&scaron;kih metala na&nbsp;antioksidantni potencijal, sposobnost&nbsp;<br />neutalizacije slobodnih radikala, aktivnosti&nbsp;antioksidantih enzima kao i&nbsp; na sadržaj&nbsp;slobodnih i konjugovanih poliamina (Put, Spm,&nbsp;Spd),&nbsp; određenih HPLC analizom,&nbsp; i sadržaj&nbsp;biljnih hormona poput indol-3-sirćetne kiseline&nbsp;i&nbsp; abscisinske &nbsp;kiseline,&nbsp; određenih GC/MS&nbsp;analizom, u listovima i korenovima klonova topola.</p><p>&nbsp;</p> / <p>The aim of this study was to estimate and compare phytoextraction capacities of three&nbsp;poplar clones (M1, B229 and Pe 19/66) in soil. Furthermore, the goal was to assess &nbsp;different biological responses among the poplar clones during exposure to different concentration of three heavy metal ions (Ni²⁺, Cu²⁺ i Cd²⁺). In order to track changes in&nbsp; poplars&rsquo;mineral, physiological, biochemical and antioxidant status during the&nbsp; abiotic stress, quantification of physiological properties, free and conjugated polyamines, total phenolics&nbsp; as well as quantification of phytohormones (indol-3-acetic and abscisic acid) was done. Furthermore, assessment of antioxidant potential by tracking radical scavenger capacities (RSC) against DPPH, ABTS, OH and NO radicals and by measuring enzymes activities (SOD, GSH-Px, GPx, GR) in vitro was performed in root and leaves of poplar clones.</p>

[ES] El tiempo de floración es uno de los caracteres más importantes que influyen en la productividad y el rendimiento de los cultivos. La identificación de compuestos sintéticos que sean bioactivos en el control de la inducción floral es de gran interés. Su identificación podría permitirnos ajustar el tiempo de floración en los cultivos, adaptándolos a las condiciones ambientales más favorables. Para identificar estos compuestos, hemos tomado dos enfoques diferentes: un cribado genético químico y la caracterización del metaboloma de transición floral. En primer lugar, realizamos un rastreo de genética química para identificar moléculas pequeñas que tengan el potencial de controlar la expresión del florígeno, FLOWERING LOCUS T (FT) o la actividad o señalización de FT en Arabidopsis. Para ello, hemos utilizado plantas transgénicas que expresan el gen ß-GLUCURONIDASE (GUS) bajo el control del promotor FT para probar una librería de 360 moléculas preseleccionadas. Los resultados positivos obtenidos se volvieron a analizar mediante un cribado secundario basado en la expresión del gen reportero LUCIFERASE (LUC) bajo el control del promotor FT. Utilizando este enfoque, hemos identificado una molécula que induce con éxito la floración en condiciones de cultivo in vitro. En segundo lugar, hemos caracterizado la función del ácido pipecólico (Pip), una molécula previamente identificada como candidata a regular la floración. Hemos confirmado que las mutaciones en las enzimas responsables de la biosíntesis de Pip muestran una alteración en la respuesta del tiempo de floración. Además, hemos identificado un nuevo papel del Pip relacionado con el crecimiento y el tamaño de la roseta de Arabidopsis. Finalmente, utilizamos un sistema inducible basado en el promotor de CONSTANS (CO) que controla la expresión del gen endógeno de CO fusionado con el receptor de glucocorticoides de rata (CO::GR). De manera que con un solo tratamiento con dexametasona podemos inducir la floración. Con este sistema, realizamos un estudio del metaboloma de muestras de ápices y hojas mediante técnicas de metabolómica dirigida, lipidómica, cuantificación hormonal y transcriptómica. La integración de estos conjuntos de datos ómicos nos ha permitido identificar rutas metabólicas que se encuentran alteradas durante la transición floral. A su vez, la caracterización de mutantes de pérdida de función que codifican enzimas clave de esas vías metabólicas, reveló que algunos de estos mutantes mostraban un fenotipo afectado para el tiempo de floración. Entre ellos, nos enfocamos en la caracterización de los genes relacionados con el metabolismo de la rafinosa, un oligosacárido de reserva. Mutantes afectados en el gen RAFFINOSE SYNTHASE 5 (RS5) presentan un fenotipo de floración temprana y fertilidad reducida. En base a los resultados obtenidos, proponemos un modelo en el que, durante la transición floral, se produce una reestructuración de las ratios entre carbohidratos sencillos (monosacáridos y disacáridos) y de reserva, como la rafinosa. Estos cambios podrían ser modulados por el ácido abscísico (ABA) y por genes relacionados con la floración, desencadenando cambios en el metabolismo de la trehalosa y promoviendo una expresión temprana de FT. / [CA] El temps de floració és un dels caràcters amb més influència en la productivitat i el rendiment dels cultius. La identificació de compostos sintètics bioactius per al control de la inducció floral és de gran interés, ja que la seua identificació podria permetre ajustar el temps de floració dels cultius, aspecte que podria contribuir a l'adaptació a condicions ambientals més favorables. Per a identificar aquests compostos, hem portat a terme dues aproximacions diferents: un garbellat genètic químic i la caracterització del metaboloma de la transició floral. En primer lloc, hem realitzat un cribratge genètic-químicper a identificar xicotetes molècules amb potencial per a controlar l'expressió del florígen, FLOWERING LOCUS T (FT) o l'activitat o la senyalització de FT a Arabidopsis. Per a portar a terme aquest cribratge, hem utilitzat plantes transgèniques que expressen el gen ß-GLUCURONIDASE (GUS) sota el control del promotor de FT amb les quals hem assajat una llibreria de 360 molècules preseleccionades de manera prèvia. Els resultats positius obtinguts en aquest cribratge t s'han sotmés a un cribratge secundari basat en l'expressió del gen reporter LUCIFERASE (LUC) sota el control del promotor FT. La utilització d'aquesta primera aproximació ha permés la idenfiticació d'una molècula que indueix amb èxit la floració en condicions de cultiu in vitro. En En segon lloc, hem caracteritzat la funció de l'àcid pipecòlic (Pip), una molècula prèviament identificada com a candidata a regular la floració. Aquesta aproximació ens ha permet confirmar que mutacions als enzims responsables de la biosíntesi de Pip comporten una alteració al temps de floració. A més, en aquest treball hem identificat un nou paper del Pip relacionat amb el creixement i la grandària de la roseta d'Arabidopsis. Finalment, hem utilitzat un sistema induïble basat en el promotor de CONSTANS (CO) que controla l'expressió del gen endogen de CO fusionat al receptor de glucocorticoides de rata (CO::GR). Aquesta construcció ens proporciona una ferramenta amb la qual induir la floració amb un sol tractament amb dexametasona. A continuació, hem realitzat un estudi del metaboloma de mostres d'àpexs i fulles mitjançant tècniques de metabolòmica dirigida, lipidómica, quantificació hormonal i transcriptòmica. La integració d'aquest conjunt de dades ómiques ens ha permés identificar les rutes metabòliques que es troben alterades durant la transició floral. Al mateix temps, la caracterització de mutants de pèrdua de funció que codifiquen enzims clau per a aquestes rutes metabòliques, ha revelat que alguns d'aquests mutants mostren un fenotip afectat pel que fa al temps de floració. Dintre dels mutants analitzats, ens hem centrat en la caracterització dels gens relacionats amb el metabolisme de la rafinosa, un oligosacàrid de reserva. Els mutants del gen RAFFINOSE SYNTHASE 5 (RS5) presenten un fenotip de floració primerenca i fertilitat reduïda. Sobre la base dels resultats obtinguts, proposem un model en el qual, durant la transició floral, es produeix una reestructuració de les ràtios entre carbohidrats senzills (monosacàrids i disacàrids) i de reserva, com la rafinosa. Aquests canvis podrien ser modulats per l'àcid abscísic (ABA) i per gens relacionats amb la floració, i desencadenariencanvis al metabolisme de la trehalosa, així com la generació de l'expressió primerenca de FT. / [EN] Flowering time is one of the most important traits affecting crop productivity and yield. The identification of natural or synthetic bioactive compounds for the control of flowering induction is of great interest. The identification of compounds with the potential to regulate flowering could allow us to fine-tune flowering responses in crops and adapt them to the changing environmental conditions. To identify these compounds, we have taken two different approaches: a chemical genetic screening and the characterization of the metabolome of floral transition. First, we performed a chemical genetic screening to identify small molecules that have the potential to control the expression of the florigen FLOWERING LOCUS T (FT) or FT activity or signaling in Arabidopsis. We used transgenic plants expressing the ß-GLUCURONIDASE gene (GUS) under the control of the FT promoter to test a preselected library of 360 molecules. Positive hits were retested by a secondary screening based on the expression of the LUCIFERASE (LUC) reporter gene under the control of the FT promoter. Using this approach, we have identified one molecule that successfully induces flowering under in vitro culture conditions. Secondly, we have characterized the function of pipecolic acid (Pip), a molecule previously identified as a candidate to regulate flowering time. We have confirmed that mutations in enzymes responsible for Pip biosynthesis display an altered flowering response. A new role for Pip in rosette growth is also revealed in this work. Finally, we used an inducible system based on the promoter of CONSTANS (CO) driving the expression of CO fused to the rat glucocorticoid receptor (CO::GR). Such a construction provides a tool to induce flowering with a single dexamethasone treatment. We then performed a comprehensive metabolomic study of the shoot apex and leaf samples that included targeted metabolomics, lipidomics, hormone quantification, and transcriptomics. Integration of these omic datasets has allowed us to point out metabolic pathways that are altered during floral induction. Characterization of loss-of-function mutants coding key enzymes of those metabolic pathways revealed that some of these mutants showed a flowering time phenotype. Among them, we focused on the characterization of the contribution of the raffinose metabolism, a storage oligosaccharide, to the determination of flowering time. Mutants affecting RAFFINOSE SYNTHASE 5 (RS5) exhibit an early flowering phenotype and reduced fertility. We propose a model in which the balance between simple and storage carbohydrates in the apex changes during floral induction. This change could be modulated by ABA and flowering-related genes, and it triggers changes in trehalose metabolism, promoting flowering by an early FT upregulation. / Praena Tamayo, J. (2022). Identification of Bioactive Molecules in the Control of Flowering Time [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/185177 / TESIS

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

This quantitative study investigated the effects of an online training program in applied behavior analysis (ABA) on stress levels of parents that have a child with autism spectrum disorder (ASD). The online ABA training program is comprised of 22 videos which take a total of 4½ hours to complete. Parenting stress levels were assessed using the Parenting Stress Inventory Short Form (PSI-SF, Abidin, 1995) and general stress levels were self-reported scores immediately before and after the training. The assessment and questionnaire were completed online immediately before the ABA training was made available and immediately after the ABA training was completed. The final PSI-SF was distributed one week after the ABA training was completed. This study confirmed that the ABA training decreased stress from the pretest to posttest but slightly increased after the delayed posttest, although delayed posttest scores remained below baseline levels. Results of the data analysis also found that general stress reduced significantly from baseline to posttests. In conclusion, the online ABA training program was an effective tool in decreasing parenting stress and general stress levels.

in English The apoplastic barriers of the root (endodermis and exodermis) represent an important regulatory mechanism for the uptake of water and nutrients from the environment, ensuring its selectivity. In addition, both layers respond to stress factors by altering its rate and degree of cell wall modification, which affects the transport properties of the root and represents adaptive plants to high heterogeneity of the soil environment. Apoplastic barriers also respond to the availability of mineral nutrients. This issue has recently been intensively studied and a number of ambiguities persist. Interestingly, the deficiency of some mineral nutrients stimulates the differentiation of barriers, while the deficiency of other mineral nutrients delays the differentiation. In addition, different plant species react differently to the deficiency of the same element. Another interesting aspect is the fact that the reaction of the endodermis and exodermis is localized and takes place mainly in that part of the root system which is directly exposed to the stress factor. This phenomenon has been observed with cadmium toxicity, but more recently with local nutrient deficiencies (nitrogen and potassium) in Zea mays. This diploma thesis deals with the functional significance of localized enhancing or delaying...

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<p>  </p> <p>Food safety researchers and extension workers are focused on educating the different actors of the supply chain, from farm to fork. To accomplish this, researchers identify areas of improvement and investigate the factors that cause or explain food safety behaviors. This thesis is divided into a systematic literature review with a meta-analysis and qualitative synthesis (Ch. 2), then two case studies that use predictive models to find top predictors of food safety behaviors (Ch.3 and 4). The systematic review (Ch.2) investigates online food safety educational programs and their effectiveness, barriers, and recommendations on different subpopulations of students, consumers, and food workers. The findings showed a limited effect on attitudes in the different subpopulations. Several areas for future research and recommendations for educators were identified. The first case study (Ch.3) developed predictive models of different food safety behaviors at ten time points throughout the COVID-19 pandemic. Findings suggest an effect between changes in COVID-19 case numbers and how well attitudes related to COVID-19 can make predictions. Additionally, findings suggest the importance of attitudes when predicting food safety behaviors. Lastly, results identified that the belief that handwashing protects against foodborne illness was more important than the belief that handwashing protects against COVID-19 when predicting handwashing at most time points. These findings can identify insights into consumer behaviors during the pandemic and several possible areas for future research. The second case study (Ch. 4) developed predictive models of consumer flour handling practices and consumer awareness of flour-related recalls and how they are affected by the total number of flour-related recalls for a state where the consumer lives. Findings identified the importance of risk perceptions in predicting consumer flour handling practices. Results also showed that younger consumers were predicted to be more likely to be aware of flour recalls than consumers of older ages. Lastly, results show that the total number of flour-related recalls for a state where the consumer lives do not affect predictions. Findings identify potential challenges to recall communication and areas for future studies.</p>

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