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186 p. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.) University of Adelaide, Dept. of Agronomy, 1989

Orientador: Leonardo Pezza / Banca: Jose Anchieta Gomes Neto / Banca: Aristeu Gomes Tininis / Resumo: A proposta apresentada por este trabalho foi estudar e desenvolver um método analítico para a determinação do herbicida paraquat em urina humana, de modo que este seja rápido, sensível, econômico e com uma menor geração de resíduos em relação aos métodos disponíveis, atualmente empregados para esta finalidade, atendendo assim os princípios e requisitos da Química Verde (Green Chemistry) e da Química Analítica Verde (Green Analytical Chemistry). Outro aspecto também abordado, é o emprego da técnica de análise por imagem digital utilizando software analítico através da geração de imagens digitais por meio das fotografias obtidas dos spot-tests, tornando a metodologia portátil e consequentemente mais acessível. O método desenvolvido consiste na reação de redução do dicátion paraquat (PQ2+) para a formação de um cátion radicalar (PQ*+) de coloração azul, utilizando uma solução de glicose (Glc) em meio alcalino (NaOH) como reagente redutor. As concentrações dos reagentes foram otimizadas para obter a maior resposta analítica possível, com o auxílio de ferramentas quimiométricas. O produto colorido possui máxima absorbância em torno de 600 nm, e, devido a coloração azul intenso desenvolvida na sua redução, tornou-se possível sua detecção e quantificação por análise das imagens digitais dos spot-tests da reação no canal de cor vermelho (canal Red do sistema RGB), utilizando-se o software livre "ImageJ - Image Processing and Analysis in Java". Através da análise da intensidade efetiv... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work was proposed study and develop an analytical method for determination and quantification of paraquat herbicide in human urine samples, so that this is rapid, sensible, economic, and lesser waste generating that the related methods in literature, currently employed for this purpose, following with Green Chemistry (G.C.) and Green Analytical Chemistry (GAC) principles. Another approached aspect is employ of Digital Image Analysis (DIA) technique using analytical software through the generating digital images photographed of the spot-tests, making the methodology portable and consequently most accessible. The method developed is based in reduction reaction between paraquat dicátion (PQ2+) for this formation of the radicalar cation (PQ*+) of blue coloring, using a glucose (Glc) solution in alkaline mean (NaOH) as reducing reagent, the reagent concentrations was being optimized for the highest analytical response possible, with the help of the chemometric tools. The colored product has max absorbance at 600 nm, and, because intense blue coloring developed in the reduction, was possible to the detection and quantification from analysis of the digital images of the spot-tests of reaction in red color channel (Red channel of the model RGB), employing the free software ImageJ - Image Processing and Analysis in Java. Through of the analysis of effective intensity (Ar) of the coloring, measured in the red color channel, was plotted an analytical curve that present linearity in... (Complete abstract click electronic access below) / Mestre

Oxidative stress is caused by an imbalance between high production of reactive oxygen species and ability of organism to detoxify them or counteract their effects. The chromosomal ends telomeres - are specialized nucleoprotein structures protecting chromosome ends from DNA damage. Telomeres of Drosophila melanogaster are arrays of specific non-long terminal repeated (LTR) retrotransposons HeT-A, TART and TAHRE. This thesis evaluates effects of exposure of paraquat, which is a strong oxidative stress inducer, on telomere length and transcription activity in Drosophila.

Parkinson’s Disease (PD) is a neurological movement disorder characterized by depletion of dopaminergic cell bodies in the substantia nigra pars compacta with subsequent loss of dopamine in the nigrostriatal pathway. PD is definitively diagnosed by the presence of intracytoplasmic inclusions in dopaminergic neurons. These inclusions are composed of a-synuclein aggregates, known as “Lewy bodies.” Lewy Bodies are known to be toxic to neurons leading to cell death. Individuals with PD most commonly manifest with bradykinesia (slowness in movement), tremors, and rigidity, but may also suffer orthostatic hypotension, dysphagia, anosmia, constipation, and sleep dysregulation. Mechanisms of PD pathogenesis may include defective protein handling, mitochondrial dysfunction, oxidative stress, and inflammation. Exposure to pesticides has long been implicated in the etiology of Parkinson’s Disease. An increasing number of epidemiological studies have linked the incidence of Parkinson’s Disease to environmental risk factors such as exposure to occupational pesticides and rural living where pesticides are known to leak into the soil and water systems far from their original area of use. The epidemiologic literature is lacking studies with large enough cohorts and accurate means to measure the exact pesticide exposure and duration of exposure. Given the extensive worldwide use of pesticides it is important to further study the associations between Parkinson’s disease and occupation exposures in larger populations.

Farmworkers in Apopka, FL, have been subjected to overhead pesticide exposure since the 1940s. Pesticides including Paraquat (PQ), Metribuzin and Aldicarb were sprayed onto the field while farmworkers worked. In "Fed Up: The High Cost of Cheap Food," farmworkers recalled the physical toll these conditions took on their bodies, blaming pesticides for their diseases, such as chronic kidney disease (CKD). While established that pesticides, specifically PQ, may be involved in some forms of Parkinson's disease, no explicit connection has been identified for SLE, CKD, and other diseases experienced by farm workers. This study evaluated whether pesticides could contribute to kidney disease. We quantified the fluorescence of reactive oxygen species (ROS) following varying PQ exposure in human embryonic kidney 293 (HEK293) cells using a microplate reader. Dosages of 75 and 150 µM were chosen based on previous literature. We also measured expression of KD biomarkers KIM-1 and NGAL upon PQ exposure with RT-qPCR. Glutathione-S-transferase pi 1 (GSTP1) served as an indicator of ROS. We predicted that ROS would increase with increasing PQ concentration, as would the fold change in the expression of the mRNA biomarker levels. The results showed a trend of increased expression of NGAL, KIM-1 and GSTP1 as PQ concentration increased. This study suggests metabolic panels may be an option when assessing patient health, especially patients susceptible to kidney disease. Future in vitro and in vivo examinations of these biomarkers are needed to clinically correlate physiological concentrations of these pesticides, and progression of kidney disease.

Research was conducted at the Mississippi State University Delta Research and Extension Center from 2016 to 2018 to determine the effects of sub-lethal concentrations of paraquat, glyphosate, saflufenacil, and sodium chlorate exposure to rice at late-season growth stages, determine the effects of exposure to sub-lethal concentrations of glyphosate or paraquat on multiple rice cultivars, and characterize the effects of paraquat exposure and Oebalus pugnax feeding on rice grain quality. In the current research, rough rice grain yields were reduced by exposure to sub-lethal concentrations of soybean desiccants 0 to 28 DAH. Rice injury was determined to not be an accurate predictor of rough rice grain yield loss as injury did not exceed 20% with any desiccant, and no injury was observed from glyphosate applications. Rough rice grain yield reductions were reflected in yield component reductions following desiccant exposure. Applications of sub-lethal concentrations of glyphosate or paraquat to rice at 50% heading caused rough rice grain yield decreases ranging from 0 to 20 and 9 to 21 % respectively. Hybrid cultivars were unaffected following glyphosate exposure at 50% heading. In the current research, observations of paraquat exposure or O. pugnax infestation of rice at the soft dough growth stage suggest rice may exhibit severe sensitivity to both events in the form of reduced kernel weight and reductions in rice milling quality. Rough rice grain yield reductions coupled with milling quality reductions and driven by the proximity of rice to corn, cotton, soybean, and sorghum in Mississippi creates the need to exercise caution when applying desiccants.

The soybean cultivars differentially sensitive to 'Kwangkyo' and 'Hood' are the bipyridylium herbicide paraquat (1,l'-dimethyl-4,4'-bipyridinium ion). This was confirmed by visible injury observations as well as by measurements of desiccation ratings, chlorophyll content, and chlorophyll fluorescence tracings of fully expanded first trifoliolate leaves of these two cultivars after exposure to a wide range of paraquat concentrations. The margin of this intraspecific differential tolerance to paraquat was narrow and the ratio of the paraquat concentrations causing 50% injury to the tolerant Kwangkyo and to the susceptible Hood (approximate tolerance factor) was found to be 10. Paraquat at 1 μM or higher inhibited rapidly the CO₂ fixation capacity of leaf mesophyll cells, isolated enzymatically from both cultivars. This result shows that the differential response does not result from any differences at the site of paraquat action in chloroplast membranes. / Ph. D.

Recent advancements in supramolecular chemistry have given a wealth of strongly binding host-guest combinations. However, the deployment of these systems into meaningful constructs has been hindered due to difficulty of synthesis or to the lack of functionality in one or both components. Systems caught in this trap were the pyridyl cryptands of dibenzo-30-crown-10 and bis(m-phenylene)-32-crown-10 paired with paraquat. Exceptionally high association constants in the range of 105 to 106 have been observed for these systems, but their applications have been hindered. Easing the implementation of pyridyl cryptands based on dibenzo-30-crown-10 was made a priority. An efficient method for the synthesis of pyridyl cryptands based on dibenzo-30-crown-10 and bis(m-phenylene)-32-crown-10 made use of the salt pyridinium bis(trifluoromethane)sulfonamide (TFSI) as a template. Optimization of the pyridinium TFSI template allowed for cyclization yields as high as 89%, as well as without the use of a syringe pump. Addressing the concern of functionality, for pyridyl cryptands, chelidamic acid was targeted as a way to build in functionality. Using a chelidamic isopropyl ester, 20 new chelidamic precursors of varying functionality were synthesized. The chelidamic derivatives fell into six groups: potential covalent monomers, initiators, chain terminators, leaving groups, aryl halides and host-guest monomers. In an attempt to boost the association constants of pyridyl cryptands based on dibenzo-30-crown-10 with paraquat, alterations to the paraquat guest were explored. It was found that the association constants could be increased by nearly an order of magnitude. Tweaks to the paraquat included changing the counterion to TFSI, methyl groups to benzyl and allowing for access to more nonpolar solvents that were previously inaccessible, such as solvent change from DCM to acetone. Two new biscryptands and two new bisparaquat TFSI monomers were synthesized. Using these monomers supramolecular polymers were synthesized and characterized. Fibers of these polymers drawn from concentrated solutions were found to be flexible and one such polymer solution was found to have an upper log / log specific viscosity–concentration slope of 3.55, which is the theoretical maximum. Additionally, a biscryptand was used to produce a chain extended polymer. Using a fundamental understanding of host-guest chemistry, work was conducted on the synthesis of norbornene monomers and polymers with pendant imidazolium tethered by ethyleneoxy linkages to aid in the stabilization of the imidazolium cation. Through the use of ethyleneoxy linkages, the free anion content and conductivity was increased. Imidazolium monomer and polymer conductivities ranged up to nearly 10-4 S/cm. Furthermore, it was determined that as long as the ethyleneoxy spacer between the norbornene and imidazolium was two units or greater, similar properties were obtained for both the monomer and corresponding polymer. Expanding the work further, the imidazolium monomers were incorporated as a soft segment into a triblock copolymer to produce a single direction mechanical actuator. / Ph. D.

Dibenzo-30-crown-10 (DB30C10) is one of the first-generation macrocyclic hosts discovered by Pedersen. Crown ethers originally attracted attention due to their ability to encapsulate metal cations and render them soluble in organic solvents. These studies helped to launch host-guest chemistry as a discipline within supramolecular chemistry. Crown ethers form complex molecules containing organic cations and neutral organic molecules. Additionally, they form components in supramolecular architectures such as catenanes, rotaxanes, and supramolecular polymers. They have been used as selective hosts in diverse applications such as wastewater treatment, switchable catalysis, therapeutic agents, sensors, molecular machines, and stimuli responsive materials "smart polymers". Despite the vigorous research activity in the field, DB30C10 has received surprisingly little attention. DB30C10 was reported in 1967 and has been commercially available since 1992; however, it has been mostly overlooked as a host in favour of smaller crown ethers such as DB24C8, B15C5, 18C6 and 15C5. Herein we present an improved synthetic route that improves the yield of the cyclization step in the synthesis of DB30C10 from 25% to 88% enabling us to prepare multiple grams of the material without the use of pseudo high-dilution techniques. The same methodology was applied to three other crown ethers with similar improvement in yield. Four new rotaxanes based on the DB30C10-paraquat binding motif were used to investigate the binding conformation of DB30C10 and paraquat. The new rotaxanes were characterized by 1H, 13C and 2D-NOESY NMR, mp, and HRMS. A single crystal X-ray structure of one of the [2]rotaxanes was obtained. To our knowledge, this is the first crystal structure of a rotaxane based on this particular binding motif. This result illustrated that DB30C10 was a suitable host for the construction of supramolecular systems and polymers. Our eventual goal is to use DB30C10 in the construction of supramolecular polymers with novel topologies. Therefore, the relative threading efficiency of DB30C10 in solution had to be determined. A series of segmented polyurethane poly(pseudorotaxanes) with paraquats in the backbone were synthesized with different crown ether or cyptand hosts. The threading efficiency was determined by 1H NMR. / Ph. D.