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Esta tese envolveu a síntese de 11 precursores poliméricos inéditos, derivados de bifenilos e terfenilos, substituídos por grupos receptores e doadores de elétrons, por meio de reações de acoplamento de Suzuki. Tais precursores foram convertidos aos respectivos polímeros, poli(p-xilileno)s e poli(p-fenileno vinileno)s, via redução catódica, conduzindo a um total de 11 polímeros, sendo dez deles inéditos. Os polímeros obtidos foram caracterizados por métodos espectroscópicos (UV-VIS, IV, RMN), análises térmicas, SEC e medidas de condutividade elétrica pós-dopagem. Um dos polímeros foi empregado na construção de dispositivos metal/polímero/metal (\"sanduíche\"), que permitiram a determinação da mobilidade dos portadores de carga, bem como da altura de barreira para injeção de elétrons na junção metal/polímero. / The synthesis via Suzuki coupling reaction of 11 new biphenylenic and terphenylenic polymer precursors, substituted by long-chain electron donating or withdrawing groups, is described. The electrochemical reduction of these precursors led to the corresponding poly(p-xylylene)s and poly(p-phenylene vinylene)s. Ten out of the 11 generated polymers have been never described before. AII the polymers were fully characterised by spectroscopic (UV-VIS, IR, NMR) and thermal analyses, as well as by SEC and electrical conductivity measurements of iodine-doped specimens. The positive charge carrier mobility and the barrier height for electron injection (metal/polymer) could be determined through I x V investigations of sandwich devices (metal/polymer/metal) for one of the polymers.

O operon pst de P. aeruginosa codifica um transportador de fosfato de alta afinida-de e também a proteína PhoU que, em conjunto, atuam como repressores da ex-pressão do regulon Pho dessa espécie. A atividade de PhoU está também associada ao metabolismo de polifosfato (poliP), dado que mutantes phoU nulos apresentam um vasto acúmulo do biopolímero. Ensaios de β-galactosidase mostraram uma alteração na expressão dos genes ppk e ppx, envolvidos no metabolismo de poliP, no mutante phoU. Observou-se que na cepa selvagem, a transcrição de ppk e de ppx não responde às limitações de Pi ou de nitrogênio, sendo esses genes altamente expressos em condições normais de crescimento. Além disso, determinou-se que ppk é co-transcrito com o gene hemB, os quais formam, portanto, um operon. O operon pst também foi analisado. Foi identificado por ensaios de northern blot o transcrito do primeiro gene do operon, pstS, que codifica uma proteína periplasmática. Também, foi identificado um promotor imediatamente a montante de phoU, o gene mais distal do operon, que permitiria sua expressão em condições normais do crescimento bacteriano. Por fim, determinou-se por ensaios de EMSA que as duas sequências consenso Pho box presentes no operon pst são completamente funcionais. / The pst operon in P. aeruginosa encodes a high-affinity phosphate transporter and the PhoU protein, which together act as repressors of Pho regulon of this species. The PhoU activity is also related with polyphosphate (polyP) metabolism, since phoU null mutants have a large accumulation of the biopolymer. β-galactosidase assays allowed to confirm a change in the expression of ppk and ppx genes, in-volved in PolyP metabolism, in the phoU mutant. It was also evidenced that in the wild type strain, the ppk and ppx transcription does not respond to Pi or nitrogen starvation, and that these genes are highly expressed under conditions of normal growth. In addition, it was determined that ppk is co-transcribed with hemB, a gene involved in the synthesis of porphyrins, and they constitute therefore an operon. The pst operon was also examined. Was identified by northern blot the transcript of the first gene in the operon, pstS, which encodes a periplasmic protein. Also, a promoter was identified immediately upstream of phoU, the most distal gene in the operon, allowing its expression in normal conditions of bacterial growth. Finally, it was determined by EMSA that the two consensus sequences Pho box present in the pst operon are fully functional.

Esta tese envolveu a síntese de 11 precursores poliméricos inéditos, derivados de bifenilos e terfenilos, substituídos por grupos receptores e doadores de elétrons, por meio de reações de acoplamento de Suzuki. Tais precursores foram convertidos aos respectivos polímeros, poli(p-xilileno)s e poli(p-fenileno vinileno)s, via redução catódica, conduzindo a um total de 11 polímeros, sendo dez deles inéditos. Os polímeros obtidos foram caracterizados por métodos espectroscópicos (UV-VIS, IV, RMN), análises térmicas, SEC e medidas de condutividade elétrica pós-dopagem. Um dos polímeros foi empregado na construção de dispositivos metal/polímero/metal (\"sanduíche\"), que permitiram a determinação da mobilidade dos portadores de carga, bem como da altura de barreira para injeção de elétrons na junção metal/polímero. / The synthesis via Suzuki coupling reaction of 11 new biphenylenic and terphenylenic polymer precursors, substituted by long-chain electron donating or withdrawing groups, is described. The electrochemical reduction of these precursors led to the corresponding poly(p-xylylene)s and poly(p-phenylene vinylene)s. Ten out of the 11 generated polymers have been never described before. AII the polymers were fully characterised by spectroscopic (UV-VIS, IR, NMR) and thermal analyses, as well as by SEC and electrical conductivity measurements of iodine-doped specimens. The positive charge carrier mobility and the barrier height for electron injection (metal/polymer) could be determined through I x V investigations of sandwich devices (metal/polymer/metal) for one of the polymers.

O operon pst de P. aeruginosa codifica um transportador de fosfato de alta afinida-de e também a proteína PhoU que, em conjunto, atuam como repressores da ex-pressão do regulon Pho dessa espécie. A atividade de PhoU está também associada ao metabolismo de polifosfato (poliP), dado que mutantes phoU nulos apresentam um vasto acúmulo do biopolímero. Ensaios de β-galactosidase mostraram uma alteração na expressão dos genes ppk e ppx, envolvidos no metabolismo de poliP, no mutante phoU. Observou-se que na cepa selvagem, a transcrição de ppk e de ppx não responde às limitações de Pi ou de nitrogênio, sendo esses genes altamente expressos em condições normais de crescimento. Além disso, determinou-se que ppk é co-transcrito com o gene hemB, os quais formam, portanto, um operon. O operon pst também foi analisado. Foi identificado por ensaios de northern blot o transcrito do primeiro gene do operon, pstS, que codifica uma proteína periplasmática. Também, foi identificado um promotor imediatamente a montante de phoU, o gene mais distal do operon, que permitiria sua expressão em condições normais do crescimento bacteriano. Por fim, determinou-se por ensaios de EMSA que as duas sequências consenso Pho box presentes no operon pst são completamente funcionais. / The pst operon in P. aeruginosa encodes a high-affinity phosphate transporter and the PhoU protein, which together act as repressors of Pho regulon of this species. The PhoU activity is also related with polyphosphate (polyP) metabolism, since phoU null mutants have a large accumulation of the biopolymer. β-galactosidase assays allowed to confirm a change in the expression of ppk and ppx genes, in-volved in PolyP metabolism, in the phoU mutant. It was also evidenced that in the wild type strain, the ppk and ppx transcription does not respond to Pi or nitrogen starvation, and that these genes are highly expressed under conditions of normal growth. In addition, it was determined that ppk is co-transcribed with hemB, a gene involved in the synthesis of porphyrins, and they constitute therefore an operon. The pst operon was also examined. Was identified by northern blot the transcript of the first gene in the operon, pstS, which encodes a periplasmic protein. Also, a promoter was identified immediately upstream of phoU, the most distal gene in the operon, allowing its expression in normal conditions of bacterial growth. Finally, it was determined by EMSA that the two consensus sequences Pho box present in the pst operon are fully functional.

<p>One of the aims of this thesis was to investigate the involvement of efflux proteins, such as the P-glycoprotein (Pgp), in the drug transport in different regions of the rat and the human intestine. The intestinal extrusion of intracellularly formed CYP3A4 metabolites, including whether this extrusion might be mediated by Pgp, was also studied. The model drugs used were local anaesthetics (LA), which have been evaluated for inflammatory bowel disease, such as ropivacaine, lidocaine and bupivacaine. The intestinal permeability to LAs was found to be high throughout all intestinal regions of the rat and human intestine. Results from the Ussing chamber model indicated only minor efflux involvement as the drug permeability was higher in the serosa to mucosa transport direction than in the opposite direction. However, the involvement of efflux in the absorption of LAs could not be verified using in situ single-pass perfusion of rat jejunum. The extrusion of the ropivacaine metabolite, 2´,6´-pipecoloxylidide (PPX), was polarized to the mucosal reservoir of the Ussing chamber for both rat and human intestinal samples, and was probably not caused by any Pgp involvement. The expression levels of CYP3A4 and efflux transporters were consistent with the enzymes’ activity in human intestine. PPX formation was mediated by CYP3A4 in human intestine, and cyp2c and cyp2d in rat intestine. Species differences were observed, as PPX was formed in rat colon, but not human colon. In conclusion, the permeability of ropivacaine, lidocaine and bupivacaine was not subjected to efflux transport of significance for their intestinal uptake. The transport of ropivacaine metabolites to the mucosal compartment was probably not mediated by Pgp. The Ussing chamber model showed consistent results with those from intestinal microsomes as far as intestinal metabolism is concerned, making it a suitable model for investigations of the interplay of efflux and metabolism. </p>

One of the aims of this thesis was to investigate the involvement of efflux proteins, such as the P-glycoprotein (Pgp), in the drug transport in different regions of the rat and the human intestine. The intestinal extrusion of intracellularly formed CYP3A4 metabolites, including whether this extrusion might be mediated by Pgp, was also studied. The model drugs used were local anaesthetics (LA), which have been evaluated for inflammatory bowel disease, such as ropivacaine, lidocaine and bupivacaine. The intestinal permeability to LAs was found to be high throughout all intestinal regions of the rat and human intestine. Results from the Ussing chamber model indicated only minor efflux involvement as the drug permeability was higher in the serosa to mucosa transport direction than in the opposite direction. However, the involvement of efflux in the absorption of LAs could not be verified using in situ single-pass perfusion of rat jejunum. The extrusion of the ropivacaine metabolite, 2´,6´-pipecoloxylidide (PPX), was polarized to the mucosal reservoir of the Ussing chamber for both rat and human intestinal samples, and was probably not caused by any Pgp involvement. The expression levels of CYP3A4 and efflux transporters were consistent with the enzymes’ activity in human intestine. PPX formation was mediated by CYP3A4 in human intestine, and cyp2c and cyp2d in rat intestine. Species differences were observed, as PPX was formed in rat colon, but not human colon. In conclusion, the permeability of ropivacaine, lidocaine and bupivacaine was not subjected to efflux transport of significance for their intestinal uptake. The transport of ropivacaine metabolites to the mucosal compartment was probably not mediated by Pgp. The Ussing chamber model showed consistent results with those from intestinal microsomes as far as intestinal metabolism is concerned, making it a suitable model for investigations of the interplay of efflux and metabolism.