A confecção da estrutura 3D do óxido de grafeno/L-cisteína foi obtida por meio da sequência de etapas descritas a seguir. Primeiramente, o óxido de grafeno foi sintetizado por meio da oxidação do grafite, utilizando permanganato de potássio e ácido sulfúrico, seguido pela esfoliação em ultrassom. Depois, a preparação do material de grafeno 3D ocorreu por auto-montagem e redução simultânea do óxido de grafeno, usando L-cisteína como agente de modelização e redução. A caracterização do material preparado deu-se por: microscopia eletrônica de varredura (MEV), análise por adsorção de nitrogênio (BET), espectroscopia na região do infravermelho com transformada de Fourier (FT-IR) e difração de raios-X (DRX). O método de análise empregado foi à cromatografia em fase líquida de alta eficiência com detector UV-Visível (HPLC-UV). Este foi desenvolvido e validado para determinação do triclosan em amostras aquosas. As figuras de mérito avaliadas foram: limite de detecção (LD) e quantificação (LQ), seletividade, linearidade e recuperação. O percentual de triclosan adsorvido em 40 mg de óxido de grafeno/L-cisteína mostrou-se elevado para soluções de triclosan em solvente, 100%; no entanto, para amostras de água de superfície fortificadas com triclosan, foi de 67,8%. A dessorção do triclosan foi praticamente completa em todas as soluções testadas, variando de 94,2% a 98,1%. A reutilização de óxido de grafeno/L-cisteína mostrou-se promissora, uma vez que apresentou adsorção completa mesmo após três ciclos consecutivos de percolação de triclosan em solvente / The construction of the 3D structure of the graphene oxide/L-cysteine was obtained by the sequence of steps described below. Firstly, graphene oxide was synthesized by oxidation of graphite using potassium permanganate and sulfuric acid, followed by ultrasonic esfoliation. Then, the preparation of 3D graphene material occurred by self-assembly and simultaneous reduction of graphene oxide, using L-cysteine as a modeling and reduction agent. The characterization of the prepared material was given by: scanning electron microscopy (SEM), nitrogen adsorption analysis (BET), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The analytical method was high performance liquid phase chromatography with UV-Visible detector (HPLC-UV). This was developed and validated for the triclosan determination. The figures of merit evaluated were: limit of detection (LOD) and quantification (LOQ), selectivity, linearity and recovery. The percentage of trichlosan adsorbed in 40 mg of graphene oxide/L-cysteine was shown to be high for solutions of triclosan in solvent, 100%; however, for surface water samples fortified with triclosan, it was 67.8%. Desiccation of triclosan was practically complete in all tested solutions, varying from 94.2% to 98.1%. The reuse of graphene oxide/L-cysteine had shown promising, since it presented complete adsorption even after three consecutive cycles of percolation of triclosan in solvent.

A confecção da estrutura 3D do óxido de grafeno/L-cisteína foi obtida por meio da sequência de etapas descritas a seguir. Primeiramente, o óxido de grafeno foi sintetizado por meio da oxidação do grafite, utilizando permanganato de potássio e ácido sulfúrico, seguido pela esfoliação em ultrassom. Depois, a preparação do material de grafeno 3D ocorreu por auto-montagem e redução simultânea do óxido de grafeno, usando L-cisteína como agente de modelização e redução. A caracterização do material preparado deu-se por: microscopia eletrônica de varredura (MEV), análise por adsorção de nitrogênio (BET), espectroscopia na região do infravermelho com transformada de Fourier (FT-IR) e difração de raios-X (DRX). O método de análise empregado foi à cromatografia em fase líquida de alta eficiência com detector UV-Visível (HPLC-UV). Este foi desenvolvido e validado para determinação do triclosan em amostras aquosas. As figuras de mérito avaliadas foram: limite de detecção (LD) e quantificação (LQ), seletividade, linearidade e recuperação. O percentual de triclosan adsorvido em 40 mg de óxido de grafeno/L-cisteína mostrou-se elevado para soluções de triclosan em solvente, 100%; no entanto, para amostras de água de superfície fortificadas com triclosan, foi de 67,8%. A dessorção do triclosan foi praticamente completa em todas as soluções testadas, variando de 94,2% a 98,1%. A reutilização de óxido de grafeno/L-cisteína mostrou-se promissora, uma vez que apresentou adsorção completa mesmo após três ciclos consecutivos de percolação de triclosan em solvente / The construction of the 3D structure of the graphene oxide/L-cysteine was obtained by the sequence of steps described below. Firstly, graphene oxide was synthesized by oxidation of graphite using potassium permanganate and sulfuric acid, followed by ultrasonic esfoliation. Then, the preparation of 3D graphene material occurred by self-assembly and simultaneous reduction of graphene oxide, using L-cysteine as a modeling and reduction agent. The characterization of the prepared material was given by: scanning electron microscopy (SEM), nitrogen adsorption analysis (BET), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The analytical method was high performance liquid phase chromatography with UV-Visible detector (HPLC-UV). This was developed and validated for the triclosan determination. The figures of merit evaluated were: limit of detection (LOD) and quantification (LOQ), selectivity, linearity and recovery. The percentage of trichlosan adsorbed in 40 mg of graphene oxide/L-cysteine was shown to be high for solutions of triclosan in solvent, 100%; however, for surface water samples fortified with triclosan, it was 67.8%. Desiccation of triclosan was practically complete in all tested solutions, varying from 94.2% to 98.1%. The reuse of graphene oxide/L-cysteine had shown promising, since it presented complete adsorption even after three consecutive cycles of percolation of triclosan in solvent.

Triclosan (TCS) is a personal care product with many fields of application and is of public interest for several years now. Monitoring studies showed that TCS is a ubiquitous chemical in the aquatic environment. Aquatic organisms are exposed to TCS in a broad range of concentrations, from ng L-1 up to lower μg L-1. TCS has a bactericidal effect for various types of gram-positive and gram negative bacteria. TCS targets a specific bacterial fatty acid biosynthetic enzyme, enoyl-[acyl-carrier protein] reductase (Schweizer, 2001). Therefore the terminal reaction in the fatty acid elongation cycle is inhibited (Levy et al., 1999). Although effects on non-target organisms are reported, the Mode of Action (MoA) of TCS is not well examined for those organisms. The aim of this PhD thesis was to investigate effects of TCS on non-target autotrophic organisms at different levels of biological complexity in the aquatic environment. In this thesis microalgae have been found to be very sensitive to TCS. In some cases even higher sensitivities than in bacteria were observed, which is in accordance with published effect data (Harada et al., 2008; Orvos et al., 2002). Similarly to bacteria, high species sensitivity differences were observed for algae (Franz et al., 2008). In bacteria these sensitivity differences can be ascribed to several resistance mechanisms reported in Schweizer (2001). These findings lead to the question about the reasons for species sensitivity differences in algae. A mesocosm study was performed to detect effects of TCS across levels of biological organization and to investigate the impact of sensitivity differences on complex aquatic communities. For that purpose, structural and functional effects parameters were observed.

No description available.

A pele humana é o maior e um dos mais importantes órgãos, esta é a principal barreira entre o corpo e o meio externo, sempre que há um desequilíbrio no mecanismo de defesa inata, o risco de uma infecção é proeminente. A queimadura é um quadro clínico em que a barreira epitelial é danificada, resultado em uma defesa imunológica deficitária e uma grande abundância de nutrientes, o que favorece a proliferação de micro-organismos. No presente estudo foi desenvolvido e caracterizado uma suspensão inovadora de nanocápsulas poliméricas de poli(ε-caprolactona) com triclosan e α-bisabol, revestida com quitosana (NCCQ) para aplicação tópica em feridas de queimadura, com intuito de reduzir a contaminação microbiana. Foram realizados ensaios de caracterização físico-química, microbiológica e cutânea. Os resultados obtidos para os ensaios de caracterização mostraram que a suspensão de nanocápsulas apresentou diâmetro de partícula adequado, ausência de cristais ou contaminação micrométrica, potencial zeta catiônico, pH levemente ácido, com uma alta eficiência de encapsulação e estável no período de trinta dias. Os ensaios microbiológicos foram realizados frente Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa e Candida albicans, através de microdiluição seriada e teste do desafio. O primeiro ensaio mostrou uma redução no valor da concentração inibitória mínima e melhores resultados para quase todas as cepas analisadas frente aos controles e dados da literatura, inclusive P. aeruginosa, a qual possui uma alta resistência ao triclosan. O teste do desafio serviu para comprovar que o efeito antimicrobiano da suspensão, se manteve ao longo de 28 dias, mesmo quando incorporada ao curativo de hemi-celulose. Os ensaios cutâneos de permeação/penetração e lavabilidade mostraram que a suspensão de nanocápsulas NCCQ teve uma retenção no estrato córneo, o que é desejável para uma formulação tópica. / The human skin is the largest and one of the most important organs, this is the main barrier between the body and the external environment, whenever there is an imbalance in innate defense mechanism, the risk of infection is prominent. Burn is a clinical condition in which the epithelial barrier is damaged, resulting in a deficient immune defense, also the abundance of nutrients favors to proliferation of microorganisms. In the present study it was developed and characterized a novel suspension of polymeric nanocapsules of poly (ε-caprolactone) with triclosan and α-bisabol coated with chitosan (NCCQ) for topical application in burn wounds, in order to reduce microbial contamination. Physical-chemical, microbiological and skin tests were performed in order to prove its applicability. The results obtained for the characterization tests showed that the suspension of nanocapsules had suitable particle diameter, no crystals or micrometric contamination cationic zeta potential, slightly acid pH with a high encapsulation efficiency and stable within thirty days. Microbiological tests were carried forward Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans, via serial microdilution and challenge test. The first experiment showed a reduction in the value of the minimum inhibitory concentration and best results for nearly all strains analyzed when compared with controls and data from the literature, including P. aeruginosa, which has a high resistance to triclosan. The challenge test was used to demonstrate that the antimicrobial effect of the suspension was maintained over 28 days even when incorporated into the dressing hemi-cellulose. The skin permeation/penetration and washability tests of NCCQ nanocapsule suspension showed that it had retention in the stratum corneum, which is desirable for a topical formulation.

Malaria is a disease that causes more than 1 million deaths per year world wide and more than 400 million clinical cases. Due to the acquired resistance of Plasmodium falciparum to the drugs used to control the infection, searching for new anti-malaria drugs is necessary in modern days. Recent studies have shown that the parasite synthesizes fatty acids using a fatty acid synthase type II (FAS-II) instead of a type-I fatty acid synthase (FAS-I) that is present in other eukaryotes. Plasmodium falciparum enoyl reductase (PfENR) is responsible for the last step of fatty acid biosynthesis in the parasite. This enzyme is located within the apicoplast, a plastid-like organelle that is responsible for several important metabolic pathways, including fatty acid biosynthesis. It is known that triclosan is an inhibitor of ENR in bacteria and we and others have shown that it is also effective against ENR in apicomplexan organisms such as P. falciparum. However triclosan cannot be used to treat malaria in humans because it has metabolic liability (glucoronidation) which limits its inhibitory potency. We have used X-ray crystallography and a Structural Activity Relationship (SAR) strategy to design and cocrystallize a tertiary complex of PfENR with NAD+ and triclosan derivatives to improve their properties as drugs to treat malaria. More than five hundred triclosan derivatives were synthesized, and their in vitro and in vivo inhibitory activity evaluated. Furthermore, structural studies were made of their affinity to interact with residues in PfENR active sites, as well as with the cofactor NAD+. A total of six PfENR-NAD+-triclosan analog/complexes structures were determined. Analogs which had replacements of chloride groups at position 5 of ring A and 4' of ring B were determined, allowing the structural analysis of the binding of these triclosan analogs to PfENR. In addition, the urea derivatives (modification at position 1) as well as phenylsulphonamides (modification at position 2') have shown to be more potent inhibitors than triclosan in the in vivo assay. The analysis of the inhibitory properties and the structure of these analogs bound to PfENR will provide novel compounds in the search for new anti-malarial drugs.

The application of municipal sewage biosolids to agricultural land is a common practice worldwide. Increasing attention is being directed at the presence of organic contaminants bound to the organic phase during wastewater treatment, which end up in the biosolids. The goal of this study was to investigate the decomposition of an alkaline-stabilized biosolid being used as an agricultural soil amendment containing unknown organic contaminants. A two year field trial and a 120 day laboratory soil incubation using increasing rates (0, 7, 14, 28, and 42 Mg ha-1) of an alkaline-stabilized biosolid (ASB) were set up to monitor biosolid decomposition and concentrations of selected contaminants over time. The seven contaminants selected for monitoring (p-cresol, indole, 4-t-octylphenol, phenanthrene, triclosan, carbamazepine, and benzo[a]pyrene) represent a wide range of physico-chemical properties and fall under several different chemical classes. The decomposition of ASB in soil was examined in the incubation study. Almost half of the CO2-C evolved from ASB amended soils occurred within the first 6 days, indicating that a relatively labile pool of carbon remains in ASB following the sewage treatment process. By day 121, between 71 to 78% of the total carbon added to soil had been evolved as CO2-C. A new model developed during this study to describe carbon mineralization, a first order plus logistic function (FLOG), performed better than other commonly used models. The method chosen to analyze organic contaminants in soil was only able to determine four out of seven compounds reliably, with recoveries greater than 50% for 4-t-octylphenol, phenanthrene, triclosan, and benzo[a]pyrene. In treated soils, only triclosan was able to be detected and quantified. Average triclosan concentration in the incubation study ranged from a high of 143 ng g-1 on day 3 to a low of 26 ng g-1 by day 121, representing an 81% decrease over a roughly 4 month period under idealized conditions. In the field, triclosan concentrations following a Fall biosolids application in Oct. 2008 increased to detectable levels (29 to 47 ng g-1) in all three plots measured in Nov. 2008, which remained elevated (29 to 66 ng g-1) over the winter period in two out of three plots when sampled in May 2009. Following the Spring application in June 2009, measured triclosan concentrations in July 2009 samples from these same two plots were lower than predicted (33 to 48 ng g-1) and eventually decreased to levels below the detection limit by the Oct. 2009 sampling.

A pele humana é o maior e um dos mais importantes órgãos, esta é a principal barreira entre o corpo e o meio externo, sempre que há um desequilíbrio no mecanismo de defesa inata, o risco de uma infecção é proeminente. A queimadura é um quadro clínico em que a barreira epitelial é danificada, resultado em uma defesa imunológica deficitária e uma grande abundância de nutrientes, o que favorece a proliferação de micro-organismos. No presente estudo foi desenvolvido e caracterizado uma suspensão inovadora de nanocápsulas poliméricas de poli(ε-caprolactona) com triclosan e α-bisabol, revestida com quitosana (NCCQ) para aplicação tópica em feridas de queimadura, com intuito de reduzir a contaminação microbiana. Foram realizados ensaios de caracterização físico-química, microbiológica e cutânea. Os resultados obtidos para os ensaios de caracterização mostraram que a suspensão de nanocápsulas apresentou diâmetro de partícula adequado, ausência de cristais ou contaminação micrométrica, potencial zeta catiônico, pH levemente ácido, com uma alta eficiência de encapsulação e estável no período de trinta dias. Os ensaios microbiológicos foram realizados frente Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa e Candida albicans, através de microdiluição seriada e teste do desafio. O primeiro ensaio mostrou uma redução no valor da concentração inibitória mínima e melhores resultados para quase todas as cepas analisadas frente aos controles e dados da literatura, inclusive P. aeruginosa, a qual possui uma alta resistência ao triclosan. O teste do desafio serviu para comprovar que o efeito antimicrobiano da suspensão, se manteve ao longo de 28 dias, mesmo quando incorporada ao curativo de hemi-celulose. Os ensaios cutâneos de permeação/penetração e lavabilidade mostraram que a suspensão de nanocápsulas NCCQ teve uma retenção no estrato córneo, o que é desejável para uma formulação tópica. / The human skin is the largest and one of the most important organs, this is the main barrier between the body and the external environment, whenever there is an imbalance in innate defense mechanism, the risk of infection is prominent. Burn is a clinical condition in which the epithelial barrier is damaged, resulting in a deficient immune defense, also the abundance of nutrients favors to proliferation of microorganisms. In the present study it was developed and characterized a novel suspension of polymeric nanocapsules of poly (ε-caprolactone) with triclosan and α-bisabol coated with chitosan (NCCQ) for topical application in burn wounds, in order to reduce microbial contamination. Physical-chemical, microbiological and skin tests were performed in order to prove its applicability. The results obtained for the characterization tests showed that the suspension of nanocapsules had suitable particle diameter, no crystals or micrometric contamination cationic zeta potential, slightly acid pH with a high encapsulation efficiency and stable within thirty days. Microbiological tests were carried forward Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans, via serial microdilution and challenge test. The first experiment showed a reduction in the value of the minimum inhibitory concentration and best results for nearly all strains analyzed when compared with controls and data from the literature, including P. aeruginosa, which has a high resistance to triclosan. The challenge test was used to demonstrate that the antimicrobial effect of the suspension was maintained over 28 days even when incorporated into the dressing hemi-cellulose. The skin permeation/penetration and washability tests of NCCQ nanocapsule suspension showed that it had retention in the stratum corneum, which is desirable for a topical formulation.

A pele humana é o maior e um dos mais importantes órgãos, esta é a principal barreira entre o corpo e o meio externo, sempre que há um desequilíbrio no mecanismo de defesa inata, o risco de uma infecção é proeminente. A queimadura é um quadro clínico em que a barreira epitelial é danificada, resultado em uma defesa imunológica deficitária e uma grande abundância de nutrientes, o que favorece a proliferação de micro-organismos. No presente estudo foi desenvolvido e caracterizado uma suspensão inovadora de nanocápsulas poliméricas de poli(ε-caprolactona) com triclosan e α-bisabol, revestida com quitosana (NCCQ) para aplicação tópica em feridas de queimadura, com intuito de reduzir a contaminação microbiana. Foram realizados ensaios de caracterização físico-química, microbiológica e cutânea. Os resultados obtidos para os ensaios de caracterização mostraram que a suspensão de nanocápsulas apresentou diâmetro de partícula adequado, ausência de cristais ou contaminação micrométrica, potencial zeta catiônico, pH levemente ácido, com uma alta eficiência de encapsulação e estável no período de trinta dias. Os ensaios microbiológicos foram realizados frente Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa e Candida albicans, através de microdiluição seriada e teste do desafio. O primeiro ensaio mostrou uma redução no valor da concentração inibitória mínima e melhores resultados para quase todas as cepas analisadas frente aos controles e dados da literatura, inclusive P. aeruginosa, a qual possui uma alta resistência ao triclosan. O teste do desafio serviu para comprovar que o efeito antimicrobiano da suspensão, se manteve ao longo de 28 dias, mesmo quando incorporada ao curativo de hemi-celulose. Os ensaios cutâneos de permeação/penetração e lavabilidade mostraram que a suspensão de nanocápsulas NCCQ teve uma retenção no estrato córneo, o que é desejável para uma formulação tópica. / The human skin is the largest and one of the most important organs, this is the main barrier between the body and the external environment, whenever there is an imbalance in innate defense mechanism, the risk of infection is prominent. Burn is a clinical condition in which the epithelial barrier is damaged, resulting in a deficient immune defense, also the abundance of nutrients favors to proliferation of microorganisms. In the present study it was developed and characterized a novel suspension of polymeric nanocapsules of poly (ε-caprolactone) with triclosan and α-bisabol coated with chitosan (NCCQ) for topical application in burn wounds, in order to reduce microbial contamination. Physical-chemical, microbiological and skin tests were performed in order to prove its applicability. The results obtained for the characterization tests showed that the suspension of nanocapsules had suitable particle diameter, no crystals or micrometric contamination cationic zeta potential, slightly acid pH with a high encapsulation efficiency and stable within thirty days. Microbiological tests were carried forward Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans, via serial microdilution and challenge test. The first experiment showed a reduction in the value of the minimum inhibitory concentration and best results for nearly all strains analyzed when compared with controls and data from the literature, including P. aeruginosa, which has a high resistance to triclosan. The challenge test was used to demonstrate that the antimicrobial effect of the suspension was maintained over 28 days even when incorporated into the dressing hemi-cellulose. The skin permeation/penetration and washability tests of NCCQ nanocapsule suspension showed that it had retention in the stratum corneum, which is desirable for a topical formulation.

Arbuscular mycorrhizal fungi, colonizing over 80% of all plants, were long thought absent in wetlands; however, recent studies have shown many wetland plants harbor arbuscular mycorrhizae (AM) and dark septate endophytes (DSE). Wetland services such as biodiversity, shoreline stabilization, water purification, flood control, etc. have been estimated to have a global value of $14.9 trillion. Recognition of these vital services is accompanied by growing concern for their vulnerability and continued loss, which has resulted in an increased need to understand wetland plant communities and mycorrhizal symbiosis. Factors regulating AM and DSE colonization need to be better understood to predict plant community response and ultimately wetland functioning when confronting natural and human induced stressors. This study focused on the effects of water quality, hydrology, sedimentation, and hurricanes on AM and DSE colonization in three wetland species (Taxodium distichum, Panicum hemitomon, and Typhal domingensis) and plant communities of coastal wetlands in Southeast Louisiana and effects of an antimicrobial biocide, triclosan (TCS), on AM (Glomus intraradices) spore germination, hyphal growth, hyphal branching, and colonization in fresh water wetland plants (Eclipta prostrata, Hibiscus laevis, and Sesbania herbacea) from bottom land hardwood forest in north central Texas. The former, mesocosm studies simulating coastal marsh vegetation ran for five years. In the latter studies, AM spores and wetland plants were exposed to 0 g/L, 0.4 g/L, and 4.0 g/L TCS concentrations in static renewal and flow through exposures for 21 and 30 days, respectively. AM and DSE colonization was significantly affected by individual and interactions of four independent variables in mesocosm experiments. Similarly, spore germination, hyphal growth, hyphal branching, and AM colonization in selected wetland plants were significantly lowered by exposure to the TCS at environmentally relevant concentrations. However, levels of effects were plant species and fungal propagules specific. My results showed that natural and human induced alterations in environmental factors and chemical contaminants can significantly impact levels of mycorrhizal spore germination, colonization, and spore density in coastal and freshwater wetland plants. The resulting impacts on plant community structure and ecosystem function require further study.