Táto práca sa zaoberá zvlákňovaním biopolymérov z taveniny. V teoretickej časti sú zhrnuté doterajšie poznatky o zvlákňovaní poly(3-hydroxy butyrátu) (PHB) a poly(mliečnej kyseliny) (PLA). Následne boli zvláknené polymérne zmesi na báze PHB s rôznym zložením, čo umožnilo štúdium vplyvu PLA, zmäkčovadiel a ich množstva na vlastnosti pripravených vlákien. Boli použité tri komerčné zmäkčovadlá (ATBC, PEG, A6) a dva experimentálne syntetizované. Zvláknenie bolo prevedené na troch rôznych zvlákňovacích linkách. Konvenčné zvlákňovacie linky s odťahovými rýchlosťami nad 150 m/min sa preukázali ako nevhodné pre spracovanie našich zmesí. Kvôli nedostatočnej pevnosti taveniny sú potrebné nízke odťahové rýchlosti. Boli pripravené vlákna s dĺžiacim pomerom 6,4; ktoré boli následne analyzované pomocou GPC, MDSC a ťahovej skúšky. Na základe nameraných teplôt skelného prechodu zmäkčovadlá ATBC a PEG vykázali lepšiu schopnosť zmäkčiť skúmané PLA/PHB zmesi. Vlákna obsahujúce A6 vykazovali najvyššiu pevnosť v ťahu (250 MPa) a modul pružnosti (2,7 GPa). Nakoniec bol skúmaný vplyv starnutia, tepla a vriacej vody na mechanické vlastnosti týchto vlákien.

Teoretická část této diplomové práce popisuje vlastnosti a možnosti modifikace poly(3-hydroxybutyrátu) (PHB) a amorfní poly(mléčné kyseliny) (PLA) a jejich směsí. V experimentální části je studována reaktivita Joncrylu, Raschigu a fosfitových činidel trifenylfosfitu, tris(nonylfenyl) fosfitu a difenylisodecylfosfitu s čistým PLA a PHB. Raschig, oligomerní aditivum na bázi polykarbodiimidu, prokázal v množství 2hm. % zvýšení viskozity taveniny obou polymerů, a proto byl použit k přípravě směsí o pěti hmotnostních poměrech PHB/(PHB+PLA). Vzorky s Raschigem a odpovídajícími nereaktivními vzorky byly studovány pomocí reologie, gelové permeační chromatografie a modulované diferenční kompenzační kalorimetrie. Výsledky naznačily reakce Raschigu v PHB/PLA směsích vedoucí k rozvětveným strukturám. Rychlost reakce však není nedostatečná ke kompenzaci poklesu viskozity v důsledku degradace při zpracování. Následně zůstává nezreagované množství Raschigu v matrici. Na základě těchto zjištění se dospělo k závěru, že Raschig se chová spíše jako relativně účinný stabilizátor reologických vlastností, než jako činidlo pro záměrnou modifikaci struktury směsí PHB/PLA. Za účelem studia mechanických vlastností těchto směsí byly ve dvoušnekovém extrudéru připraveny vzorky plastifikovány acetyltributylcitrátem.

Einleitung: Monocarboxylattransporter (MCT) 1 & 4 sind in zahlreichen Geweben als Kotransporter für Monocarboxylate und Protonen beschrieben. Auch im Pansenepithel werden MCT benötigt, um kurzkettige Fettsäuren (SCFA) aus dem Pansenlumen in die Pansenepithelzelle aufzunehmen (MCT4) und um SCFA und deren Metabolite aus der Pansenepithelzelle in das Blut auszuschleusen (MCT1). Die transepitheliale Permeation von SCFA über die Pansenwand ist von enormer Bedeutung, da sie die wichtigste Energiequelle der Wiederkäuer darstellen. Die beteiligten Transportprozesse müssen dementsprechend einer Anpassung an variierende Mengen von SCFA unterliegen. Bisherige Studien bei anderen Spezies deuten auf eine Regulation des MCT1 auf mRNA Ebene über den Peroxisom-Proliferator-aktivierten Rezeptor α (PPARα) hin. Ziele der Untersuchung: Das Ziel dieser Arbeit war herauszufinden, ob MCT1 in ovinen Pansenepithelzellen über PPARα reguliert wird und ob auch MCT4 dieser Regulation unterliegt. Eine gleichzeitige Regulation beider Transporter läge nahe, da sie gemeinsam an der transepithelialen Permeation beteiligt sind. Die Auswirkungen solch einer Regulation auf die Proteinexpression und die Transportleistung der MCT sollte charakterisiert werden. Ebenfalls war das Potenzial der bei erhöhter Kraftfutterfütterung vermehrt anfallenden SCFA Butyrat auf die MCT1 Expression zu untersuchen. Material & Methoden: Aus dem Vorhof von Schafen wurden Pansenepithelzellen gewonnen und entsprechend einer bereits etablierten Methode kultiviert. Nach einer Subkultivierung wurden die Zellen immunzytochemisch mit Antikörpern gegen MCT1, MCT4 und Na+/K+-ATPase untersucht, um deren Lokalisation in den kultivierten Pansenepithelzellen zu bestimmen. Weiterhin erfolgte eine Behandlung mit WY 14.643, einem spezifischen, synthetischen PPARα Agonisten, sowie mit GW 6471, einem Antagonisten des PPARα. Mittels qPCR wurden die relativen mRNA Mengen von MCT1, MCT4, ACO, CPT1A und CACT bestimmt und auf die Referenzgene GAPDH und Na+/K+-ATPase normalisiert. Die Proteinexpression von MCT1 und MCT4 wurde mittels Western Blot bestimmt. Zur funktionellen Quantifizierung wurde der intrazelluläre pH-Wert der Zellen mittels Spektrofluorometrie gemessen und der laktatabhängige Protonentransport als Vergleichswert zwischen den Behandlungen genutzt. Um den MCT-abhängigen Teil des Transportes zu bestimmen, wurde ein spezifischer MCT1 & 4 Inhibitor, die p-Hydroxymercuribenzensulfonsäure (pHMB) eingesetzt. Die Zellen wurden mit Butyrat über einen Zeitraum von 6 und 48 h induziert. Die Erfassung der MCT1 Expression erfolgte mittels semiquantitativer PCR. Ergebnisse: MCT1 & 4 sind sowohl in der Zellmembran als auch intrazellulär in den Pansenepithelzellen lokalisiert. Die mRNA Expressionsdaten konnten zeigen, dass MCT1 und die PPARα Zielgene durch WY 14.643 hochreguliert werden konnten, wohingegen die MCT4 Expression keine eindeutige Antwort auf die Stimulation zeigt. Die Behandlung mit den Antagonisten zeigt eine Abhängigkeit der MCT1 Expression von PPARα, die MCT4 Expression konnte dagegen nicht beeinflusst werden. Mittels pHMB gelang es, den laktatabhängigen Protonenexport fast vollständig zu blocken. Sowohl laktatabhängiger Protonenexport als auch die Proteinexpression zeigten keine Änderung durch WY 14.643 Stimulation. Die Butyratexposition veränderte die Morphologie der Pansenepithelzellen und schien nicht geeignet für Untersuchungen der mRNA Expression zu sein. Schlussfolgerungen: Es konnte in dieser Arbeit erstmals gezeigt werden, dass MCT1 in Pansenepithelzellen über PPARα reguliert wird, nicht aber MCT4. PPARα scheint demnach einer der entscheidenden Angriffspunkte für die Regulation des SCFA Transportes zu sein, dessen natürliche Liganden im Pansen aber noch nicht bekannt sind. Damit legt diese Arbeit den Grundstein für regulative Studien am intakten Pansenepithel. / Introduction: Monocarboxylate transporters (MCT) 1 & 4 are cotransporters of monocarboxylates and protons in a variety of mammalian cell types. In the ruminal epithelium MCT are necessary to transport short-chain fatty acids (SCFA) from the lumen into the ruminal epithelial cell (MCT4) and to discharge SCFA and their metabolites from the cell into the blood (MCT1). Transepithelial permeation of SCFA is of great importance, because they are the main source of energy for ruminants. The regulation of appropriate transport proteins should thus be subject to the adaptation to varying SCFA amounts. Previous studies in other species suggested that gene expression of MCT1 is regulated by peroxisome proliferator-activated receptor α (PPARα), a ligand-activated nuclear receptor. Aims: The aim of the study was to examine if MCT1 in ruminal epithelial cells is regulated by PPARα and furthermore if MCT4 can be regulated by PPARα, as well. A simultaneous regulation seems likely, because both are acting jointly in the transepithelial transporting of SCFA. The implications of such a regulation on protein expression and transport capacity of MCT should be characterized. The effect of butyrate, a SCFA which increases under concentrate feeding, on MCT1 expression was determined. Materials & Methods: Ruminal epithelial cells of sheep were cultivated according to methods previously established. After subcultivation, immunocytochemistry with antibodies against MCT1, MCT4 and Na+/K+-ATPase was performed to determine their localization in ruminal epithelial cells. For studying the influence of PPARα, WY 14.643, a synthetic and selective ligand of PPARα, and GW 6471, a synthetic antagonist of PPARα, were applied to the culture medium of the cells. After processing the specimens, the relative amount of mRNA of MCT1, MCT4 and the target genes ACO, CPT1A and CACT were analyzed by qPCR and normalized on the reference genes GAPDH and Na+/K+-ATPase. Protein abundance of MCT1 & 4 was measured by using the Western Blot method. Functional quantification was measured by the intracellular pH (pHi) of cells using spectrofluorometry as well as comparing the effect of WY 14.643 treatment on lactate-dependent proton export. To determine the MCT-dependent part of the pHi recovery, p-hydroxymercuribenzoic acid (pHMB), a specific inhibitor of MCT1 & 4, was applied. Cells were also treated with butyrate for 6 h and 48 h and the mRNA abundance of MCT1 was analyzed by semiquantitative PCR. Results: Both MCT1 and MCT4 were localized in the cell membrane as well as in the cytoplasm of ruminal epithelial cells. By qPCR it could be demonstrated that the mRNA abundance of MCT1 and PPARα target genes in the ruminal epithelial cells was increased by WY 14.643 in comparison to untreated cells, whereas the response of MCT4 did not yield distinct results. Treatment with the PPARα antagonist pointed out, that MCT1 is influenced by PPARα, but not MCT4. Lactate-dependent proton export was blocked almost completely by pHMB. Both lactate-dependent proton export and protein expression were not altered by WY 14.643 treatment. Butyrate exposure changed the morphology of ruminal epithelial cells and seemed unsuitable for the analysis of mRNA expression. Conclusion: For the first time, it could be demonstrated, that MCT1 in ruminal epithelial cells is regulated by PPARα, but not MCT4. PPARα seems to be a vital target in the rumen for SCFA transport regulation, whose natural triggers have yet to be identified. Furthermore, this study provides the basis for regulative studies on intact ruminal epithelium.

[ES] En respuesta a estreses de tipo biótico y abiótico, las plantas sintetizan proteínas de defensa y compuestos químicos de diversa naturaleza. Estos compuestos pueden actuar de manera directa, a través de propiedades antioxidantes, antifúngicas o antibacterianas, o actuar como metabolitos defensivos indirectos. Dentro de este último grupo de compuestos defensivos, cabe destacar a los compuestos fenólicos y los compuestos orgánicos volátiles (VOCs). En nuestro grupo de investigación se ha profundizado en el estudio de estos metabolitos secundarios implicados en la respuesta defensiva de las plantas. Por una parte, se identificó el ácido gentísico (GA) como una molécula señal que actúa de manera complementaria al ácido salicílico (SA) en infecciones de tipo sistémico. Además, se ha tratado de profundizar en el estudio de la biosíntesis del GA a través de la enzima salicilato 5-hidroxilasa (S5H), encargada de la conversión de SA a GA. Para ello, se ha llevado a cabo la caracterización fenotípica, molecular y química de plantas transgénicas de tomate que tienen silenciado el gen S5H mediante la técnica de RNA de interferencia (RNAi_S5H) frente a infecciones de tipo bacteriano y viroidal. Las plantas de tomate RNAi_S5H presentaron un aumento de resistencia frente a Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) y el viroide de la exocortis de los cítricos (CEVd). Del mismo modo, se llevaron a cabo análisis metabolómicos de estas plantas transgénicas RNAi_S5H tras ambas infecciones, observándose diferencias relacionadas con el metabolismo del SA, que parecen indicar que la homeostasis del SA es específica para cada interacción tomate-patógeno. Por otra parte, se identificaron algunos ésteres de (Z)-3-hexenol que eran emitidos de manera diferencial tras la infección bacteriana con la cepa avirulenta de Pst DC3000 en plantas de tomate cv. Rio Grande. Concretamente, tratamientos exógenos con el compuesto volátil butanoato de (Z)-3-hexenilo (HB) fueron capaces de inducir de manera significativa el cierre de estomas, la activación de genes defensivos y un aumento en la resistencia frente a la infección bacteriana. La eficacia de este compuesto como inductor de cierre estomático fue comprobada en diferentes cultivos agronómicos, como Arabidopsis, Medicago, Zea, Citrus y Nicotiana, confirmando su papel como un inductor de cierre estomático universal. Dado el potencial de este compuesto en agricultura, se emplearon aproximaciones genéticas, bioquímicas y farmacológicas para descifrar el mecanismo de señalización del cierre estomático mediado por HB. Una vez el volátil es percibido por los receptores de la planta, se activan diferentes componentes de la cascada de señalización defensiva, como canales permeables de Ca2+ o la producción de especies reactivas de oxígeno (ROS). Asimismo, el HB es capaz de desencadenar la activación de las proteínas quinasas activadas por mitógenos MPK3 y MPK6, induciendo el cierre estomático de una manera independiente a la síntesis y señalización mediada por ácido abscísico (ABA). Por último, la eficacia del HB fue evaluada en condiciones de campo frente a estreses tanto de tipo biótico como abiótico y en procesos de desarrollo como la maduración, proponiendo un uso del HB como un nuevo compuesto fitoprotector natural para el control de estreses de forma sostenible en agricultura. / [CA] En resposta a estressos de tipus biòtic i abiòtic, les plantes sintetitzen proteïnes de defensa i compostos químics de diversa naturalesa. Aquests compostos poden actuar de manera directa, a través de propietats antioxidants, antifúngiques o antibacterianes, o actuar com a metabòlits defensius indirectes. Dins d'aquest últim grup de compostos defensius, cal destacar als compostos fenòlics i els compostos orgànics volàtils (VOCs). En el nostre grup d'investigació s'ha aprofundit en l'estudi d'aquests metabòlits secundaris implicats en la resposta defensiva de les plantes. D'una banda, es va identificar l'àcid gentísic GA) com una molècula senyal que actua de manera complementària a l'àcid salicílic (SA) en infeccions de tipus sistèmic. A més, s'ha tractat d'aprofundir en l'estudi de la biosíntesi del GA a través d l'enzim salicilato 5-hidroxilasa (S5H), encarregada de la conversió de SA a GA. Per a això, s'ha dut a terme la caracterització fenotípica, molecular i química de plantes de transgèniques de tomaca que tenen silenciat el gen S5H mitjançant la tècnica d'RNA d'interferència (RNAi_S5H) enfront d'infeccions de tipus bacterià i viroidal. Les plantes de tomaca RNAi_S5H van presentar un augment de resistència enfront de Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) i el viroide de la exocortis dels cítrics (CEVd). De la mateixa manera, es van dur a terme anàlisi metabolómics d'aquestes plantes transgèniques RNAi_S5H després de totes dues infeccions, observant-se diferències relacionades amb el metabolisme del SA, que sembla indicar que l'homeòstasi del SA és específica per a cada interacció tomaca-patògena. D'altra banda, es van identificar alguns èsters de (Z)-3-hexenol que eren emesos de manera diferencial després de la infecció bacteriana amb el cep avirulent de Pst DC3000 en plantes de tomaca cv. Rio Gran. Concretament, tractaments exògens amb el compost volàtil butanoato de (Z)-3-hexenilo (HB) van ser capaces d'induir de manera significativa el tancament d'estomes, l'activació de gens defensius i un augment en la resistència enfront de la infecció bacteriana. L'eficàcia d'aquest compost com a inductor de tancament estomàtic va ser comprovada en diferents cultius agronòmics, com Arabidopsis, Medicago, Zea, Citrus i Nicotiana, confirmant el seu paper com un inductor de tancament estomàtic universal. Donat el potencial d'aquest compost en agricultura, es van emprar aproximacions genètiques, bioquímiques i farmacològiques per a desxifrar el mecanisme de senyalització del tancament estomàtic mediat per HB. Una vegada el volàtil és percebut pels receptors de la planta, s'activen diferents components de la cascada de senyalització defensiva, com a canals permeables de Ca2+ o la producció d'espècies reactives d'oxigen (ROS). Així mateix, el HB és capaç de desencadenar l'activació de les proteïnes cinases activades per mitógens MPK3 i MPK6, induint el tancament estomàtic d'una manera independent a la síntesi i senyalització mediada per l'àcid abscísic (ABA). Finalment, l'eficàcia del HB va ser avaluada en condicions de camp enfront d'estressos tant de tipus biòtic com abiòtic, i en processos de desenvolupament com la maduració, proposant un l'ús del HB com a nou compost fitoprotector natural per al control d'estressos de manera sostenible en agricultura. / [EN] In response to biotic and abiotic stress, plants synthesize defence proteins and chemical compounds from diverse nature. These compounds can act directly, trough antioxidant, antifungal or antibacterial properties, or indirectly as defensive metabolites. Among these group of defensive metabolites, phenolic compounds and volatile organic compounds (VOCs) present a major role. Our research group have a strong background in studying the role of plant secondary metabolites in plant defence mechanisms. On one hand, gentisic acid (GA) was first described as a signal molecule that acts complementary to salicylic acid (SA) in systemic infections. Furthermore, SA conversion to GA trough the salicylate 5-hydroxylase enzyme (S5H) has received much attention. For this purpose, S5H-silenced transgenic tomato plants (RNAi_S5H) have been phenotypically, molecularly, and chemically characterized against both, bacterial and viroidal inoculations. RNAi_S5H tomato plants resulted in enhanced resistance to both Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) and Citrus Exocortis Viroid (CEVd). Moreover, metabolomics analysis of these transgenic plants upon bacterial and viroid infections revealed differences related to SA metabolism, suggesting that SA homeostasis is specific for each tomato-pathogen interaction. On the other hand, some esters of (Z)-3-hexenol were identified to be differentially emitted by tomato cv. Rio Grande plants upon infection with the avirulent strain of the bacterium Pst DC3000. Particularly, treatments with the volatile (Z)-3-hexenyl butyrate (HB) resulted in significant stomatal closure, defence genes induction and enhanced resistance to the bacteria. Moreover, the efficacy of this compound as a stomata closer was tested in different agronomic crop as Arabidopsis, Medicago, Zea, Citrus y Nicotiana plants, postulating HB as a new universal stomata closer. Due to its potent properties, the signalling pathway of the HB-mediated stomata closure has been deciphered by using different genetic, biochemical, and pharmacological approaches. The perception of this volatile by plant receptors appeared to initiate different defence signalling events, including the activation of Ca2+ permeable channels or reactive oxygen species (ROS) burst. Moreover, HB triggered the activation of the mitogen-activated protein kinases MPK3 and MPK6, inducing stomatal closure independently of abscisic acid (ABA) biosynthesis and signalling. Additionally, HB efficacy has been also tested in field conditions and against both biotic and abiotic stresses, and also during ripening, proposing HB as a new natural phytoprotector for the sustainable control of stresses in agriculture. / This work was funded by Grant AICO/2017/048 from the Generalitat Valenciana and by Grant INNVAL10/18/005 from the Agència Valenciana de la Innovació (Spain). / Payá Montes, C. (2023). Secondary Metabolites in Plant Defence Mechanisms [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/193041

The large intestinal epithelium is confronted with the necessity to adapt quickly to varying levels of oxygenation. In contrast to other tissues, it meets this requirement successfully and remains unharmed during (limited) hypoxic periods. The large intestine is also the site of bacterial fermentation producing short-chain fatty acids (SCFA). Amongst these SCFA, butyrate has been reported to ameliorate many pathological conditions. Thus, we hypothesized that butyrate protects the colonocytes from hypoxic damage. We used isolated porcine colon epithelium mounted in Ussing chambers, incubated it with or without butyrate and simulated hypoxia by changing the gassing regime to test this hypothesis. We found an increase in transepithelial conductance and a decrease in short-circuit current across the epithelia when simulating hypoxia for more than 30 min. Incubation with 50 mM butyrate significantly ameliorated these changes to the epithelial integrity. In order to characterize the protective mechanism, we compared the effects of butyrate to those of iso-butyrate and propionate. These two SCFAs exerted similar effects to butyrate. Therefore, we propose that the protective effect of butyrate on colon epithelium under hypoxia is not (only) based on its nutritive function, but rather on the intracellular signaling effects of SCFA.

No description available.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2007 / Cerebrovascular disease and coronary heart disease (CHD) are of the most important causes of morbidity and mortality amongst South Africans. The risk factor prevalence for stroke and CHD becomes altered by changes in lifestyle, including diet. In general it is suggested that lifestyle management should be the first choice when having to treat patients with increased cardiovascular risk. The prudent low-fat, high-fibre diet is regarded as an apparently healthy diet. It is suspected that this diet is effective for the control of known coronary risk factors as well as raised clotting factors. Research studies have shown the addition of dietary fibre to the diet as a promising therapeutic agent for the limited control of known coronary risk factors. The physiological effects of dietary fibre in humans are significantly influenced by the degree to which fibre is fermented in the colon. Fermentation results in the production of short-chain fatty acids (SCFAs); acetate, propionate and butyrate. The aim of this study was to examine the possible effects of different combinations of short-chain fatty acids on some metabolic risk markers. In this study a group of westernised African male volunteers was recruited and randomly assigned to three groups. Group one received a placebo. Group two received a supplement containing 50% acetate and 50% propionate. Group three received a SCFA supplement in the ratio of 70% acetate, 15% propionate and 15% butyrate. Supplementation was sustained for a period of six weeks. Blood samples were drawn during the different visits. At baseline the study group represented a group of black African men without any apparent metabolic or physical abnormalities. All measured variables fell within the normal range. In the placebo group, there was a statistically significant decrease in plasma fibrinogen levels from baseline to the end of supplementation. In the acetatepropionate supplement study group a statistically significant decrease in factor VIII (from 91.1 ± 11.2 to 90.9 ± 8.3%, respectively), and ATIII (from 114.3 ± 13.1 to 108.34 ± 9.5%), as well as a statistically significant decrease in low-density lipoprotein cholesterol (LDL-C) from 3.10 ± 0.79 to 2.64 ± 0.73 mmol/L. The significant increase in %HDL-C from 26.3 ± 6.5 to 30.2 ± 9.3% should also be noted. Both triglycerides (8%) and plasma fibrinogen (2%) showed a statistically significant increase. However, these changes are of no clinical significance. For the high-acetate supplement study group (with the addition of butyrate), a statistically significant decrease in factor VII (from 102.5 ± 13.7 to 101.1 ± 6.4%), VIII (from 92.6 ± 12.8 to 87.6 ± 6.0%), ATIII (from 109.2 ± 16.0 to 103.0 ± 9.9%) as well as fibrin monomer concentration (from 13.9 ± 2.2 to 12.1 ± 3.6 mg/L), were measured. Fibrin network compaction increased significantly from 14.2 ± 4.6 to 13.7 ± 4.0%. Other changes include a statistically significant increase in the serum-TC of 4.2%. From the results it is evident that the acetate-propionate supplement, with exclusion of butyrate, has a beneficial effect on metabolic parameters when compared to a highacetate- propionate supplement. The results do provide evidence of a possible therapeutic application for the propionate-acetate containing supplement. The specific mechanism should, however, still be investigated. It can be concluded from this study that acetate, propionate and butyrate each have different effects on human metabolism. It is evident that the use of a mixture of acetate and propionate may have a beneficial effect on patients at risk of developing CVD. Further studies that investigate the optimum ratio of these two products may lead to the development of a naturally derived therapeutic product for the prevention or treatment of CVD in black African men, as well as the population at large.

Le syndrome de l'intestin irritable (SII) touche près de 10% de la population. Nous avons utilisé un modèle animal de SII induit par le butyrate développé au laboratoire afin de décortiquer les mécanismes de l'hypersensibilité colique (HSC) dans le SII. Le blocage du NGF par des anticorps anti-NGF prévient l'HSC induite par le butyrate, évaluée par le test de distension colorectale. Le NGF, quantifié par immunohistochimie (IHC), est surexprimé dans les ganglions rachidiens dorsaux (GRD) innervant le côlon des rats butyrate. Le blocage des canaux ASIC par amiloride prévient l'HSC induite par le butyrate. L'expression des ARNm ASIC1a et ASIC1b, évaluée par RT-PCR, est augmentée dans les GDR des rats butyrate. Cette augmentation est corrélée à une augmentation de l'expression de la protéine ASIC1A dans les neurones nociceptifs, quantifiée par IHC. Le blocage du NGF par des anticorps anti-NGF prévient la surexpression de ASIC1A dans les GRD. L'absence de variation d'expression du NGF et de ASIC1A au niveau colique suggère que ces moléciles ont une implication dans l'élément présynaptique plutôt que dans les terminaisons libres coliques. L'étude de l'expression spinale de la protéine Fos après stimulation des fibres coliques a montré que l'HSC induite par le butyrate est associée à une activation spécifique des segments thoraciques T10-T11-T12 de la moëlle épinière (MEp). Le blocage spinal du canal ASIC1A par la PcTx1 prévient l'HSC induite par le butyrate. L'expression de ASIC1a, évaluée par RT-PCR et Western blot, est augmentée dans la MEp des rats butyrate. Comme à la périphérie, l'expression de ASIC1a est modulée par le NGF puisque le blocage du NGF prévient la surexpression des ARNm et de la protéine ASIC1A dans la MEp des rats butyrate. En conclusion, ce travail de thèse suggère que le NGF et le canal ASIC1A jouent un rôle critique dans le développement de douleurs viscérales en contribuant à la fois à la sensibilisation périphérique et centrale.

With the advent of industrialization and food processing techniques the sizes of the cereal bran have been drastically reduced. In my thesis, I have tested the effect, if any, of wheat bran and maize bran particle size, in vitro, on the gut microbiota community structure by 16S rRNA sequencing and their function, by Short chain fatty acids (acetate, propionate, butyrate) production. In turn, we also linked the microbiota and SCFA differences to different chemical composition amongst variously sized fractions of wheat and maize bran.

O presente trabalho visou preparar e caracterizar eletrólitos poliméricos (EP) à base de poli(vinil butirato) (PVB) com diferentes sais de lítio (LiClO4, LiCF3SO3 e LiI/I2), com ou sem o plastificante g-butirolactona (GBL), além de viabilizar a aplicação dos mesmos em dispositivos eletrocrômicos e células solares. Observou-se, através das análises por espectroscopia de impedância eletroquímica, que o PVB é capaz de solvatar no máximo 40% de sal de lítio em massa. Foi verificado que as condutividades iônicas dessas amostras, em função do aumento da temperatura, podem ser explicadas pelo modelo Vogel-Tammann-Fulcher, e que o eletrólito PF04 (PVB com 40% de LiCF3SO3) possui o maior valor de condutividade (1,5´10-4 S/cm) com relação às outras amostras. Os espectros de infravermelho das amostras estudadas mostraram um deslocamento nos picos correspondentes às carbonilas da matriz polimérica em resposta à coordenação das mesmas com íons Li+. Os resultados da espectroscopia Raman comprovaram a presença do par redox (I3-/I-) no eletrólito com LiI/I2. Os difratogramas de raios-X do PVB evidenciaram um pico largo centrado em 20º (2q) com 800 c.p.s. de intensidade, a adição de LiI/I2 e LiCF3SO3 ao polímero reduziu as intensidades para 750 e 700 c.p.s respectivamente, ao contrário do observado com LiClO4, onde se nota que o sal não foi completamente solvatado pelo polímero. A micrografia obtida por microscopia eletrônica de varredura (SEM) do eletrólito com 23% de LiClO4 (amostra P04) mostraram evidências de aglomerados iônicos na superfície. As análises por calorimetria exploratória diferencial (DSC) mostraram que um aumento na concentração de sal adicionado ao polímero causou uma diminuição na temperatura de transição vítrea (Tg), e que os eletrólitos possuem em torno de 44% de cristalinidade. Os eletrólitos P04 e PF04 foram aplicados em janelas eletrocrômicas, apresentando uma diferença de 10,5 e 9,3% respectivamente entre os estados colorido e descolorido. O eletrólito com LiI/I2 foi aplicado em célula solar gerando uma fotocorrente máxima de 1,09 mA/cm2 e eficiência de 0,41% sob a irradiação de 100 mW/cm2. Eletrólitos géis com adição de 90% γ-butirolactona também foram aplicados em células solares, os valores de fotocorrente e eficiência foram incrementados (5,82 mA/cm2 e 2,1%, respectivamente). / The aim of the present study was to prepare and characterize polymer electrolytes (EP) based on poly(vinyl butyrate) (PVB) with different lithium salts (LiClO4, LiCF3SO3 and LiI/I2) and/or containing g-butyrolactone (GBL), and to apply them in electrochromic devices and solar cells. It was observed through electrochemical impedance spectroscopy that the PVB is able to solvate up to 40% in weight of lithium salt. It was found that the ionic conductivity of these samples, as a function of temperature, can be explained by Vogel-Tammann-Fulcher model, and the electrolyte PF04 (PVB with 40% of LiCF3SO3) had the highest conductivity value of 1,5´10-4 S/cm when compared to other samples. Infrared spectra of the samples showed a shift in the peaks corresponding to the carbonyl groups of the polymer matrix in response to their coordination with Li+ ions. The results of Raman spectroscopy confirmed the presence of the redox couple (I3-/I-) in the electrolyte with LiI/I2 (PVB04). The X-ray diffractograms of the PVB showed a broad peak centered at 20 (2q) com intensity of 800 cps. The addition of LiI/I2 and LiCF3SO3 to the polymer matrix decreased the intensities to 750 and 700 cps respectively, but not after the LiClO4 addition, which was explained by its not complete solvatation by the polymer matrix. The Scanning Electron Microscopy (SEM) pictures of electrolyte with 23% of LiClO4 (P04 sample) showed evidences of ion clusters on the surface. The analyzes via Differential Scanning Calorimetry (DSC) showed that an increase in the concentration of the salt added to the polymer matrix caused a decrease in glass transition temperature (Tg), and that electrolytes are about 44% crystalline. The electrolytes P04 and PF04 were applied to electrochromic windows (ECDs) and showed a transmittance difference of 10.5 and 9.3%, respectively between the colored and discolored states. The electrolyte with LiI/I2 was applied to dye sensitized solar cell (DSSC) generating a maximum photocurrent of 1.09 mA/cm2 and 0.41% of efficiency under irradiation of 100 mW/cm2. Gel electrolytes containing 90% of γ-butyrolactone were applied to DSSC and showed 5.82 mA/cm2 of photocurrent and 2.1% of efficiency.