This dissertation focuses on understanding the complex interactions between hydrological and geochemical processes, and specifically how these interactions are affected by subsurface heterogeneity across scales. Heterogeneity in the form of macropores and fractures provide preferential flowpaths and affect contaminant transport. Biogeochemical processes are also strongly affected by such heterogeneities. Any lithological layering or interface (e.g. plume fringe, wetland-aquifer boundary, etc.) increases biogeochemical activity around that interface. Hydrologic conditions, rainfall events, drainage patterns, and pH variations are also dominant controls on redox processes and thereby affect contaminant distribution and migration. An inherent limitation of modeling fate and transport of contaminants in the subsurface is that the interactions among biogeochemical processes are complex and non-linear. Therefore, this research investigates the effect of hydrological variations and physical heterogeneity on coupled biogeochemical processes across column and landfill scales. Structural heterogeneity in the form of macropore distributions (no macropore, single macropore, and multiple macropores) in experimental soil columns is investigated to accurately model preferential flow and tracer transport. This research is crucial to agricultural systems where soil and crop management practices modify soil structure and alter macropore densities. The comparison between deterministic and stochastic approaches for simulating preferential flow improved the characterization of interface parameters of the dual permeability model, and outlined the need for efficient sampling algorithms or additional datasets to yield unique (equifinal) soil hydraulic parameters. To evaluate the effect of heterogeneity on redox processes, repacked soil columns with homogeneous and heterogeneous (layered) profiles from soil cores collected at the Norman Landfill site, Oklahoma, USA were employed. Results indicate that heterogeneity in the form of textural layering is paramount in controlling redox processes in the layered column. To evaluate the effect of hydrologic conditions on redox processes, temporal data at the Norman landfill site was used. Results indicate that seasonal hydrologic variations exert dominant control over redox-sensitive concentrations. An integrated MCMC algorithm was devised to upscale linked biogeochemical processes from the column to the field scale. Results indicate that heterogeneity and hydrologic processes are paramount in controlling effective redox concentrations at the Norman landfill site.

Along with an increasing understanding of the harmful effects on the environment of a wide range of pollutants has come the need for more sensitive, faster and less expensive detection methods of identification and quantitation. Many environmental pollutants occur in low levels and often in complex matrices thus analysis can be difficult, time consuming and costly. Because of the availability and easy cultivation of the microorganisms with potentially high specificity, there is considerable interest in the use of living microorganisms as the analytical component (the biocomponent) of sensors for pollutants. While a number of biosensors using bacteria have been developed, yeast has been comparatively rarely used as the biocomponent. Yeast are attractive because they are easy to culture and they are eukaryotes which means their biochemistry is in many respects closer to that of higher organisms. This thesis describes the development of whole cell bioassays that use yeast cells as a sensing element and redox mediators to probe the intracellular redox reactions to monitor the catabolic activity of the yeast resulting from the external substrate, steady-state voltammetry is utilised as the electrochemical detection technique. The isogenic differential enzyme analysis (IDEA) concept of Lincoln Ventures Limited, lead NERF funded research consortium uses bacteria that have been cultured using specific organic pollutants as the carbon source which are the biocomponent in sensors. The use of wild type yeast Arxula adeninivorans that has the ability to use a very wide variety of substrates as sources of carbon and nitrogen was used as an alternative to bacteria to validate the “IDEA” concept. Naphthalene and di-butyl phthalate were chosen as model target contaminant molecules. The performance, detection limits and the usefulness of yeast based biosensor applications for environmental analysis are discussed. This thesis also describes the development and optimisation of a simple, cost effective in vivo estrogens bioassay for the detection of estrogens using either genetically modified or a wild type yeast Saccharomyces cerevisiae. In this study, catabolic repression by glucose was exploited to achieve specificity to estrogens in complex environmental samples that eliminates the requirement for conventional sample preparation. This is the first time that the use of wild type yeast to quantify estrogens has been reported. The attractive features of the bioassay are its use of a non-GMO organism, its speed, its high specificity and sensitivity with a detection limit of 10-15 M. The similarity of binding affinities for major estrogens to those of human estrogens receptors makes this in vivo estrogen bioassay very useful for analytical/screening procedures. The electrochemical detection method also makes it easy to interface with a variety of electronic devices.

Chemnitz, Techn. Univ., Diss., 2007.

Η ολοκληρωμένη εκτίμηση της θειολικής οξειδοαναγωγικής κατάστασης (ΘΟΚ) ενός οργανισμού ιστού ή κυττάρου είναι πολύ σημαντική καθώς οξειδοαναγωγικές αλλαγές των διαφόρων θειολικών μορίων συνδέονται με το οξειδωτικό στρες και με αρκετές ασθένειες. Η γενική ΘΟΚ (ΓΘΟΚ) χαρακτηρίζεται από τις συγκεντρώσεις ορισμένων συνόλων θειολικών μορίων στην αναγμένη και την οξειδωμένη μορφή τους (θειολικά οξειδοαναγωγικά ζεύγη). Αυτά τα ζεύγη μπορεί να είναι μη πρωτεϊνικά (non-protein ή NP) (όπως NPSH και NPSSNP με το NP να συμβολίζει οποιαδήποτε άλλη μη πρωτεϊνική θειόλη) ή πρωτεϊνικά (protein ή P) (όπως PSH, PSSP και PSSNP). Ειδικότερα, οι κυριότερες μη πρωτεϊνικές θειόλες γλουταθειόνη (GSH) και κυστεΐνη (CSH) μαζί με τα συμμετρικά, μεικτά δισουλφίδιά τους και τις οξειδωμένες τους μορφές (GSSG, PSSG, PSSC, NPGSHox, NPCSHox,) είναι τα οξειδοαναγωγικά ζεύγη τα οποία χαρακτηρίζουν την ειδική ΘΟΚ (ΕΘΟΚ), καθώς είναι εκείνα που απαντώνται σε υψηλότερη συγκέντρωση στους οργανισμούς. Στη διεθνή βιβλιογραφία δεν υπάρχει μεθοδολογία για την ταυτόχρονη ποσοτικοποίηση των θειολικών μορίων που χαρακτηρίζουν τη ΘΟΚ των οργανισμών. Συνεπώς, στόχος της παρούσας μελέτης είναι η ανάπτυξη μιας νέας μεθόδου ποσοτικοποίησης τόσο της ΓΘΟΚ όσο και της ΕΘΟΚ, που να είναι εφαρμόσιμη σε όλους τους οργανισμούς. Για το διαχωρισμό πρωτεϊνικών και μη πρωτεϊνικών μορίων χρησιμοποιήθηκε το τριχλωροακετικό οξύ που σε ορισμένη συγκέντρωση (>5%) καταβυθίζει αποτελεσματικά όλες τις πρωτεΐνες. Ο ποσοτικός προσδιορισμός των δισουλφιδικών μορίων και οξειδωμένων μορφών (NPSSNP, PSSP, PSSNP, GSSG, NPGSHox, NPCSHox, PSSG και PSSC) πραγματοποιήθηκε μετά από αναγωγή τους (με το αντιδραστήριο tributyl phosphine), ενώ ο ποσοτικός προσδιορισμός των ελεύθερων θειολών (PSH, NPSH, GSH και CSH) πραγματοποιήθηκε χωρίς την αναγωγή τους. Ειδικότερα, η ποσοτικοποίηση των αναγμένων διθειολικών ομάδων (δισουλφιδίων) και των ελεύθερων θειολών έγιναν με τα αντιδραστήρια 4,4-dithiodipyridine (για τις -SH ομάδες των αναγμένων δισουλφιδίων, καθώς και για τις ελεύθερες NPSH και PSH), o-phthalaldehyde (για την GSH, GSSG και NPGSHox) και νινυδρίνη (για την CSH και την NPCSHox), σε συνδυασμό με κατάλληλη μαθηματική επεξεργασία βασισμένη στη στοιχειομετρία των αντιδράσεων αναγωγής. Η υψηλή ευαισθησία της μεθόδου (στο επίπεδο του nmol) την καθιστά εφαρμόσιμη ακόμη και σε βιολογικά δείγματα χαμηλής περιεκτικότητας σε θειόλες (όπως πχ. το οφθαλμικό και το εγκεφαλονωτιαίο υγρό). / The thiol redox state (TRS) is an essential condition of prokaryotic and eukaryotic cells associated with all major biological processes. The general TRS (GTRS) part of it, is characterized by the levels of all thiol compounds of protein or non-protein origin in their reduced or oxidized form (thiol redox couples), while the specific TRS (STRS) by the levels of certain thiols, reduced and oxidized, free or membrane bound. The GTRS redox couples are composed of non-protein (NP) (such as NPSH and NPSSNP) or protein (P) (such as PSH, PSSP and PSSNP) thiols. On the other hand, the STRS redox couples are composed of the main non-protein thiol glutathione (GSH) and cysteine (CSH) together with their symmetric, mixed disulfides and oxidized forms (GSSG, PSSG, PSSC, NPGSHox, NPCSHox). In light of the fact that there is not available any appropriate method in literature for the simultaneous determination of the main thiol components that characterize TRS, a new method is developed for the purpose of this study for the quantification of GTRS and STRS, applicable to any organism. For the separation of protein from non protein thiols, trichloroacetic acid was chosen (at 5%) as the most effective protein precipitant. The determination of disulfides and oxidized forms (NPSSNP, PSSP, PSSNP, GSSG, PSSG, PSSC, NPGSHox and NPCSHox) was accomplished after their reduction with the tributyl phosphine (which, because of its hydrophobicity effectively reduces protein thiols as well), whereas the quantification of free thiols (PSH, NPSH, GSH and CSH) was accomplished without reduction. Reduced disulfides and free thiols were quantified by the more effective than DTNB 4,4-dithiodipyridine (for the determination of -SH groups of reduced disulfides as well as of free NPSH and PSH), o-phthalaldehyde (for the specific determination of GSH, GSSG and NPGSHox) and ninhydrin (for the specific determination of CSH and NPCSHox). The high sensitivity of the method (in the level of nmoles) makes it applicable even in biological samples of very low thiol concentration (such as ophthalmic or cerebrospinal fluid).

Les zones de subduction sont les plus grands systèmes de recyclage de notre planète. Elles permettent le recyclage de l'eau contenue dans la croûte océanique hydratée et de la lithosphère du manteau supérieur. L'eau joue un rôle clé dans de nombreux processus associés aux zones de subduction, comme la tectonique des plaques, la production de magma, le transport élémentaire et la génération de tremblement de terre. La composition chimique, le contenu H2O de la lithosphère océanique, l'âge et la géométrie de la plaque océanique sont les principaux facteurs contrôlant les processus de subduction, y compris la déshydratation.L'objectif principal de cette thèse est d'étudier le régime de la libération de l'eau depuis la plaque océanique subductante et le comportement du Fe et du S en contenus dans les serpentinites, qui représentent la principale lithologie de roche hydratées océaniques. L'approche expérimentale de ce travail permet d’étudier les changements chimiques et minéralogiques associés lors la déshydratation des serpentinites de différentes compositions. Un certain nombre de techniques d'analyse ont été utilisées pour étudier l’influence de la composition de la roche totale sur la composition des assemblages produits. Les intervalles de pression de température expérimentalement étudiés, à savoir 2 GPa et 450-900C, représentent des zones de subduction chaudes. L'extrapolation à d'autres gradients géothermiques communs a été faite par thermodynamique. Les compositions de serpentinite étudiées correspondent aux péridotites serpentinisées naturelles décrites pour la lithosphère océanique.Mon travail indique que la teneur en Fer contrôle a stabilité thermique d’antigorite. Déshydratation de serpentinites avec Fe, par conséquent, pasee à des températures plus basses par rapport aux assemblages Fe-libres. La déshydratation observée dans les systèmes sans Fer se fait le long d'une réaction univariante, alors que dans les systèmes contenant du Fer, la déshydratation se fait sur un domaine de température (réactions de déshydratation divariantes). De plus, la présence de Al dans serpentinite stabilise clinochlore, qui conserve 15% de l'eau initiale jusqu'à ~ 120 km (820°C/2 GPa) dans subduction chaud. Cette dépendance sur Fe et Al apporte importance de considérer non seulement la géométrie et l'âge de la plaque océanique, mais aussi une composition de lithologies lors de la modélisation et d’interprétation de subduction. Une comparaison entre la profondeur des séismes et la profondeur de déshydratation des serpentinites indique une possible contribution de la libération de l'eau à la sismicité dans les zones de subduction chaudes et à pente faible.La spectroscopie d'absorption des rayons X montre une réduction progressive de Fe et de S dans des serpentinites. Le rapport Fe3+/ Fetotal, de la roche totale, élevé dans la serpentinite, diminue dans les assemblages anhydres de haute température par décomposition de la magnétite (< 550°C) et de l’antigorite (700°C). La pyrite des serpentinites se transforme en pyrrhotite en-dessous de 450°C et induit une libération de ¼ de soufre initial, probablement sous forme de H2S. La magnétite et la pyrite présentes dans des serpentinites, sont des phases cruciales pour la production de fluides très oxydés et d’espèces volatiles soufrées qui peuvent être transportés depuis la plaque subductée vers le coin mantellique. Application des résultats montre que les fluides s’élevant de la plaque océanique sont responsables de l'oxydation du manteau; et décomposition de la magnétite et l’antigorite avec au moins 100°C différence peut provoquer une libération de fluides chimiquement différents à peu profond (basse-T) et profondes (T-élevé) parties de subduction. / Subduction zones are the largest recycling systems of our planet. Subduction zones involve recycling of water from hydrated oceanic crust and lithosphere to the upper mantle. Water plays a key role in subduction zone processes, including plate tectonics, magma generation, elemental transport and earthquake generation. The chemical composition, H2O content of oceanic lithosphere sinking to the mantle, age and geometry of subducting oceanic slab are the main factors controlling subduction zone processes including dehydration.The principle aim of this dissertation is to investigate the regime of water release from subducting oceanic plate and the associated behavior of Fe and S in serpentinites, which are the main carriers of water into the slab. The experimental approach of my work allows one to compare chemical and mineral changes occurred during dehydration of serpentinites with different composition. A number of analytical techniques were applied to study the influence of bulk rock composition on the mineral chemistry of produced assemblages. The experimentally investigated pressure-temperature ranges, i.e. 2 GPa and 450-900C, are representative for hot subduction zones. The extrapolation to other common geothermal gradients was done through thermodynamic modeling. The investigated serpentinite compositions correspond to natural serpentinized peridotites described for oceanic lithosphere.Bulk Fe content was demonstrated to decrease thermal stability of antigorite by 25C on average. Dehydration of Fe-bearing serpentinites, consequently, occurs at lower temperatures compared to Fe-free assemblages. Dehydration reactions observed in Fe-free systems are univariant reactions, while in Fe-bearing systems, serpentinites dehydration appears over a range of temperature through divariant reactions. Moreover, the presence of Al in serpentinite stabilized clinochlore, which retains 15% water initial contain in serpentinite down to ~120km (820°C/2 GPa) within hot subduction. Such a dependence of serpentinite dehydration on bulk Fe and Al brings importance of considering not only geometry and the age of the slab, but also a composition of slab lithologies while modeling and interpreting processes in subduction zone. A comparison of the depths of serpentinite dehydration and seismicity revealed a strong correlation and therefore a potential contribution of water release to seismicity in the case of hot subduction zones (i.e., Chili type subduction).X-ray absorption spectroscopy measurements revealed a progressive reduction of Fe and S in investigated serpentinites. The bulk Fe3+/Fetotal ratio initially high in serpentinite is shown to decrease in anhydrous and higher temperature assemblages due to magnetite and Fe3+-bearing antigorite breakdown at <550°C and 700°C, respectively. The presence of pyrite in serpentinite, which transforms to pyrrhotite below 450°C, imposes a release of ¼ of initial sulfur, in H2S form. The presence of magnetite and pyrite in serpentinite, is crucial and responsible for the production of highly oxidized fluids and volatile sulfur species, which can be transported from the subducting slab into the mantle wedge. Application of results, obtained in the present study, to nature demonstrates that fluids rising from subducting slab are responsible for oxidation of overlying mantle, and in addition, magnetite and antigorite breakdown which occurs with at least 100°C difference may cause a release of chemically different fluids at shallow (low-T) and deep (high-T) parts of subduction.

Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2016-01-04T17:41:31Z No. of bitstreams: 2 silvia_mourao_magalhaes.pdf: 1033681 bytes, checksum: 4abcd5281d35fd4412fc135e71a22dda (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2016-01-04T17:41:47Z (GMT) No. of bitstreams: 2 silvia_mourao_magalhaes.pdf: 1033681 bytes, checksum: 4abcd5281d35fd4412fc135e71a22dda (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-01-04T17:41:47Z (GMT). No. of bitstreams: 2 silvia_mourao_magalhaes.pdf: 1033681 bytes, checksum: 4abcd5281d35fd4412fc135e71a22dda (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) / Este estudo avaliou o efeito agudo e cr?nico do exerc?cio intervalado de alta intensidade sobre o estado redox sangu?neo de homens sedent?rios. Para isso, o estudo foi dividido em duas etapas. Na primeira etapa 17 indiv?duos sedent?rios foram submetidos a uma sess?o de exerc?cio intervalado de alta intensidade (HIIE, do ingl?s high intensity interval exercise), no cicloerg?metro, composta por 8 est?mulos, a 90% da pot?ncia m?xima, intercalados por 75 segundos de recupera??o ativa a 30 watts. Antes e, imediatamente, ap?s o exerc?cio amostras de sangue foram coletadas para a avalia??o da concentra??o de subst?ncias reativas ao ?cido tiobarbit?rico (TBARS) e da capacidade antioxidante total do plasma; e a concentra??o de TBARS e atividade das enzimas antioxidantes super?xido dismutase (SOD) e catalase (CAT), no lisado eritrocit?rio. Agudamente, o HIIE n?o alterou a concentra??o plasm?tica de TBARS, embora a capacidade antioxidante total do plasma tenha sido significativamente menor (p=0,05) imediatamente ap?s o exerc?cio. N?s eritr?citos, a concentra??o de TBARS foi significativamente menor (p=0,03), enquanto a atividade da SOD foi significativamente maior (p=0,04), imediatamente ap?s o exerc?cio. Na segunda etapa 9 indiv?duos, que participaram do HIIE, foram submetidos a um programa de treinamento intervalado de alta intensidade (HIIT, do ingl?s high intensity interval training), 3 vezes por semana, durante 4 semanas (12 sess?es de treinamento). Par?metros do estado redox foram avaliados antes e ao final do treinamento. O HIIT aumentou (p=0,05) a capacidade antioxidante total do plasma, e, nos eritr?citos, a concentra??o de TBARS foi menor (p=0,03) e a atividade da catalase foi maior (p=0,04) ap?s o treinamento. As modifica??es do estado redox sangu?neo alcan?adas em curto prazo com o programa de HIIT utilizado neste estudo podem ser consideradas uma resposta ben?fica adicional para a esta modalidade de treinamento, e neste contexto o HIIT pode ter um papel terap?utico nas condi??es cl?nicas decorrentes ou associados a um quadro de desequil?brio redox. / Disserta??o (Mestrado) ? Programa Multic?ntrico de P?s-gradua??o em Ci?ncias Fisiol?gicas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2014. / ABSTRACT This study evaluated the acute and chronic effects of high intensity interval exercise on blood redox state of sedentary men. For this, the study was divided into two moments. First, 17 sedentary subjects underwent a session of high intensity interval exercise (HIIE), on a cycle ergometer, consisting of 8 stimuli, at 90% of maximum power, with intervals of active recovery of 75 seconds, at 30 watts. Before and immediately after exercise, blood samples were collected to evalute plasma thiobarbituric acid reactive substances (TBARS) concentration and plasma total antioxidant capacity; and TBARS concentration and activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), at erythrocyte lysate. Acutely, HIIE did not alter plasma TBARS concentration, although plasma total antioxidant capacity was significantly lower (p=0,05) immediately after exercise. In erythrocytes, TBARS concentration was significantly lower (p=0,03), while SOD activity was significantly higher (p=0,04) immediately after exercise. In the second moment, 9 individuals, who participated in HIIE, underwent a high-intensity interval training (HIIT) program, 3 times a week, during 4 weeks (12 training sessions). Redox state parameters were evaluated before and at the end of training. HIIT increased (p=0,05) plasma total antioxidant capacity and, in erythrocytes, TBARS concentration was lower (p=0,03) and catalase activity was higher (p=0,04) after training. Changes on blood redox state promoted by HIIT can be considered an additional beneficial response to this type of training, and HIIT may have a therapeutic role in clinical conditions associated with redox imbalance.

SILVA, Fredy Davi Albuquerque. Homeostase redox, genes associados e a resistência do feijão-de-corda [Vigna unguiculata (L.) Walp.] ao fungo hemibiotrófico Colletotrichum gloeosporioides [(Penz) Penz & Sacc.]. 2015. 145 f. Tese (Doutorado em bioquímica)- Universidade Federal do Ceará, Fortaleza-CE, 2015. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-07-28T15:47:22Z No. of bitstreams: 1 2015_tese_fdasilva.pdf: 13172308 bytes, checksum: eec041dd293481a11b32a2b64584598a (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-08-02T14:43:25Z (GMT) No. of bitstreams: 1 2015_tese_fdasilva.pdf: 13172308 bytes, checksum: eec041dd293481a11b32a2b64584598a (MD5) / Made available in DSpace on 2016-08-02T14:43:25Z (GMT). No. of bitstreams: 1 2015_tese_fdasilva.pdf: 13172308 bytes, checksum: eec041dd293481a11b32a2b64584598a (MD5) Previous issue date: 2015 / Colletotrichum gloeosporioides is an important hemibiotrophic pathogen with a broad host range that causes substantial crop losses. Recent data have shown that the hypersensitive response (HR) is one event involved in the resistance of cowpea (V.unguiculata) genotype BR-3 against C.gloeosporioides (LPVD-1 isolate). Several studies have been undertaken on the defense mechanism of plant to hemibiotrophic pathogen, but overall they remain poorly understood. Previously, we have compared changes in protein expression induced in resistant cowpea genotype after infection with C.gloeosporioides using a proteomic approach. Based on these results, in the present study, we evaluated the defense responses induced by C.gloeosporioides in V.unguiculata associated with oxidative burst, accumulation of reactive oxygen species (ROS) such as superoxide anion (O2•-), hydrogen peroxide (H2O2) as well expression of antioxidant genes using RT-qPCR analysis. At the same time, we analyzed the C.gloeosporioides infection kinetics by optical microscopy (OM) and scanning electron microscopy (SEM). Increased O2•- and H2O2 was detected in cowpea 2 hours after inoculation (hai) using NBT and DAB staining, respectively. Spectrophotometric measurements showed two peaks H2O2 production, 2 and 12 hai, showing a biphasic kinetics. The increase of H2O2 was accompanied by lipid peroxidation 2 and 48 hai. OM and SEM analyzes showed that C.gloeosporioides was able to generate germ tubes and structures such as apressoria and develop under the surface of the leaves. However, despite of the development and attempt to infection, ultra-structural changes were observed on the surface of conidia and hyphae, 8 hai led to no infection of host cells. Analysis by RT-qPCR demonstrated that the genes VuFeSODI and VuCuZnSODII are up- regulated in chloroplasts at 4 hai, while the gene VuCuZnSODI was well up-regulated 12 hai. In relation to genes associated to scavenging of H2O2, VuPrxIIBCD showed a strong up-regulated of transcript at 2 hai while that VuAPXI showed up-regulated only 12 hai. VuCATI and VuCATII showed that the quantitative level of transcript expression was up- regulated 12 hai, indicating that they are important in the maintenance of H2O2 in peroxisomes. Contrarily, VuPrxIIE transcript was down-regulated in the early hours after inoculation, but showed increased expression levels at 48 hai suggesting participate in the regulation of H2O2 in chloroplasts. The present study indicates that H2O2 has an important role in the initial defense strategies of cowpea acting against C.gloeosporioides and functioning as a signaling molecule. Furthermore, genes associated with antioxidant defenses studied here seem to be involved, in combination with other molecules, in the regulation of H2O2 levels toward preventing cell death and regulating the cell redox homeostasis, important events in the resistance mechanisms of plants to pathogens. / Colletotrichum gloeosporioides é um importante patógeno hemibiotrófico com uma ampla gama de hospedeiros que causa perdas substanciais de colheitas. Dados recentes mostraram que a resposta hipersensitiva (HR) é um evento envolvido na resistência do feijão-de-corda (V.unguiculata) genótipo BR-3 contra C.gloeosporioides (isolado LPVD-1). Vários estudos têm sido realizados sobre os mecanismos de defesa de plantas a patógenos hemibiotróficos, mas em geral eles continuam a ser mal compreendidos. Anteriormente, comparamos mudanças na expressão de proteínas induzidas em genótipos resistentes de feijão-de-corda após a infecção com C. gloeosporioides utilizando uma abordagem proteômica. Com base nesses resultados, no presente estudo, avaliamos as respostas de defesa induzidas por C.gloeosporioides em V.unguiculata associadas com a explosão oxidativa, o acúmulo de espécies reativas de oxigênio (EROs), como o ânion superóxido (O2•-), e o peróxido de hidrogênio (H2O2), bem como a expressão de genes antioxidantes, utilizando análise por RT-qPCR. Ao mesmo tempo foi analisada a cinética de infecção de C.gloeosporioides por microscopia óptica (MO) e microscopia eletrônica de varredura (MEV). O aumento de O2•- e H2O2 foi detectado em feijão-de-corda, 2 horas após a inoculação (hai) utilizando coloração por NBT e DAB, respectivamente. A quantificação espectrofotométrica demonstrou dois picos de produção de H2O2, 2 e 12 hai, mostrando uma cinética bifásica. O aumento de H2O2 foi acompanhado por peroxidação lipídica 2 e 48 hai. As análises de MO e MEV mostraram que C.gloeosporioides foi capaz de gerar estruturas tais como tubos germinativos e apressórios e se desenvolver sob a superfície das folhas. No entanto, apesar do desenvolvimento e tentativa de infecção, alterações ultra-estruturais foram observadas na superfície de conídios e hifas 8 hai levando a não infecção de células hospedeiras. Análise por RT-qPCR demonstrou que os genes VuFeSODI e VuCuZnSODII apresentaram aumento de expressão 4 hai, enquanto que o gene VuCuZnSODI foi bem expresso 12 hai. Em relação aos genes associados à regulação de H2O2, VuPrxIIBCD mostrou uma forte aumento de transcristos em 2 hai enquanto que, VuAPXI mostrou aumento de expressão apenas 12 hai. VuCATI e VuCATII mostram aumento de expressão quantitativa dos transcritos 12 hai, indicando que eles são associados a manutenção de H2O2 em peroxissomos. Contrariamente, a expressão dos transcritos de VuPrxIIE foi reprimida nas primeiras horas após a inoculação, contudo, apresentaram níveis aumentados de expressão em 48 hai, sugerindo participar na regulação de H2O2 nos cloroplastos. O presente estudo indica que H2O2 tem um papel importante nas estratégias de defesa iniciais de feijão-de-corda, agindo contra C.gloeosporioides e funcionando como uma molécula sinalizadora. Além disso, os genes associados com defesas antioxidantes estudados parecem estar envolvidos, em combinação com outras moléculas, na regulação dos níveis de H2O2 para prevenir a morte celular e regular a homeostase redox, eventos importantes nos mecanismos de resistência de plantas a patógenos.

The utility of fluorophores for sensing applications in the current state of the art of biological imaging hardly needs to be stated. The use of fluorophores in exploring and determining the internal structure and active dynamics of cellular processes has been pivotal, allowing us to explore areas of study inaccessible through other means. A simple search of fluorophores in Scifinder© demonstrates their popularity, as the number of hits increases year after year, until the year of 2015 when there were 1400+ journal articles published with the phrase. Fluorophore applications range far and wide, from sensing applications related to environmental concerns, to public health, to clinical usage. Fluorophores have been developed to detect explosive residues, to monitor environmental pollutants, and even to detect illicit substances. In cellular applications, a fluorophore needs to be well suited to examining the relevant processes, including participating in the cellular milieu and actively signifying the phenomena that are desired. Chapter I examines the usage of alkynes in fluorescent sensing scaffolds and gives a survey of their applicability in the field. Chapter II demonstrates the utility of disulfide-based macrocyclic scaffolds in the design of supramolecular hosts for chloride anions and their use as solid-state sensors for these anions. Chapter III explores the synthesis and application of an alkyne-based scaffold in the reversible detection of dithiol/disulfide redox flux and a new mode of quantification of dithiol-disulfide redox couples, a classically difficult area of study. Chapter IV focuses on methods utilized to improve the disulfide-based redox sensing capabilities. Chapters V and VI explore the properties of a new fluorophore scaffold discovered during research into another sensing scaffold, demonstrating a new reaction which yields a heretofore underexplored heterocycle with novel photophysical and supramolecular behaviors. This dissertation contains both previously published and unpublished co-authored material.

Hydrogen sulfide (H2S) is an important biomolecule for its role in mediating redox homeostasis and signaling biological processes. The study of biological sulfide is currently impeded by a lack of tools available that adequately address the questions currently facing the field. The most pressing of these questions are: how does H2S signal biological processes. To produce tools for studying H2S, chemiluminescent scaffolds were designed to study both H2S producing enzymes and directly measure free H2S. Additionally, small molecule organic persulfides were synthesized and characterized in order to study the properties and reactivity of H2S signaling species. By creating methods to directly measure biological H2S and creating model systems to investigate the active signaling species, the biological reactivity of H2S can be better understood. The luminescent methods for detecting H2S were developed in order to avoid photodecomposition inherent with fluorescent methods while still providing a spectroscopic readout for performing measurements in cells. D-cysteine concentrations can be measured using luciferin bioluminescence, and utilized to back out the H2S producing activity of DAO. Free H2S was measured using luminol derived chemiluminescence. The luminol scaffolds were studied in depth to determine what makes an H2S probe selective for H2S in order to inform the design of future H2S probes. Sulfide signaling processes were investigated using organic persulfide model systems. We found that under reducing conditions persulfides liberate free H2S, and that under basic conditions they decompose. The decomposition pathway is governed by substitution at the -carbon, which dictates the steric accessibility of the inner sulfur atom to act as an electrophile. Persulifdes do not react with acids, and are easily tagged by electrophiles to form disulfides. Persulfides are sufficiently reducing to generate NO from nitrite, facilitating cross-talk between multiple signaling species. This cross talk is mediated by formation of perthionitrite, which may function as an independent signaling species.

SANTOS, Regina Claudia Rodrigues dos. Catalisadores Bimetálicos de Óxidos de Mo–Cu (Ni ou Co) Suportado em Alumina para Conversão do Glicerol a Intermediários Químicos. 2016. 180 f. Tese (Doutorado em química)- Universidade Federal do Ceará, Fortaleza-CE, 2016. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-06-03T18:54:35Z No. of bitstreams: 1 2016_tese_rcrsantos.pdf: 6015189 bytes, checksum: 86723da2f9784a9b0c3f1f5efd908211 (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-07-20T20:47:28Z (GMT) No. of bitstreams: 1 2016_tese_rcrsantos.pdf: 6015189 bytes, checksum: 86723da2f9784a9b0c3f1f5efd908211 (MD5) / Made available in DSpace on 2016-07-20T20:47:28Z (GMT). No. of bitstreams: 1 2016_tese_rcrsantos.pdf: 6015189 bytes, checksum: 86723da2f9784a9b0c3f1f5efd908211 (MD5) Previous issue date: 2016 / The economic viability of biodiesel production depends of the use of glycerol, by-product with multifunctional structure, considered a bio-renewable feedstock of great potential to be transformed to fuel or higher value-added chemicals products. In order to contribute to the development of this research area, study was carried out in order to explore the catalytic potential γ-Al2O3 modified with molybdenum oxide and promoter (Cu, Ni or Co) in the glycerol dehydration reaction to chemical intermediates with industrial application was performed. The strategy was to synthesize Al2O3 spheres by hybrid method with interesting structural, textural and chemical properties for then impregnating with precursors of metals via unconventional method (Pechini). The material composition was chosen with the aim of evaluating the bifunctional effect caused by the combination of acid-base and redox properties of molybdenum catalysts supported on alumina. For comparison was evaluated commercial Ni-Mo/Al2O3 catalyst with high acidity and porosidade. The catalysts were characterized for: ICP-OES, XRF, TGA/DTA, XRD, SEM, IR, H2-TPR, TPD-CO2, N2 adsorption/desorption isotherms, and acidity measurements through pyridine adsorption. The catalytic performance was evaluated in the glycerol dehydration under N2 or H2 flow at atmospheric pressure and 250°C. The modification in the activity and selectivity due to the change of carrier gas are attributed to the changes of acid/redox properties of the catalyst, as suggested by acidity measurements and TPR-H2. Acrolein was the main product observed for all catalysts, but the cupper containing catalyst (CuMoAl) showed higher catalytic activity and, and superior selectivity to allyl alcohol, as well as the production of 1-propanol, which is due to the hydrogen transfer. This selectivity agrees with H2-TPR results, which show stronger effect of the copper over the molybdenum oxide reduction, if compared to the others promoter (Co or Ni). At the end it is proposed the reaction steps mechanism for the glycerol conversion to allyl alcohol. / A viabilidade econômica da produção do biodiesel depende do uso do glicerol, subproduto com estrutura multifuncional, considerado matéria–prima bio-renovável, de grande potencial para ser transformado a combustíveis ou produtos químicos de maior valor agregado. Com o intuito de contribuir para o desenvolvimento dessa linha de pesquisa, foi realizado estudo do potencial catalítico da γ-Al2O3 modificada com óxido de molibdênio e promotores (Cu, Ni ou Co), na reação de desidratação do glicerol a intermediários químicos com aplicação industrial. A estratégia foi sintetizar esferas de Al2O3 por método híbrido, as quais apresentam interessantes propriedades estruturais, texturais e químicas para em seguida impregnar com precursores dos metais via método não-convencional (Pechini). A composição dos materiais foi escolhida com o objetivo de avaliar o efeito bifuncional causado pela combinação das propriedades ácido/básicas e redox de catalisadores de molibdênio suportado em alumina. Para fins comparativos foi testado catalisador comercial Ni-Mo/Al2O3 com elevada acidez e porosidade. Os catalisadores foram caracterizados por: ICP-OES, FRX, TGA/DTA, DRX, MEV, IV, TPR-H2, TPD-CO2, isotermas de adsorção/dessorção de N2, e acidez através de adsorção de piridina. O desempenho dos catalisadores foi avaliado na desidratação do glicerol, sob fluxo de N2 ou H2, a 1atm e 250°C. As mudanças na atividade e seletividade devido à troca do gás de arraste estão associadas a alterações nas propriedades ácido/redox dos catalisadores, como sugerido pelas medidas de acidez e TPR-H2. Acroleína foi o principal produto observado para todos os catalisadores, porém a amostra contendo cobre (CuMoAl), mostrou maior atividade catalítica e superior seletividade a álcool alílico, bem como produção do 1-propanol; o que está associado a transferência de hidrogênio. Essa seletividade concorda com resultados de TPR-H2, que mostram maior influência do cobre sobre a redução do óxido de molibdênio, quando comparado aos promotores (Co ou Ni). Ao final são propostos passos reacionais envolvidos na conversão do glicerol a álcool alílico.