959 research outputs found
Morphology of Metzgeria conjugata Lindb. (Metzgeriales, Hepaticopsida)
Scanning electron microscopy and light microscopy were used to elucidate the morphology of Metzgeria conjutata Lindb. and confirm the presence of 2 rows of epidermal cells on the dorsal surface, (21-3) rows on the ventral surface, midrib with cells in (3-51-6) tiers; hirsute, short hairs, straight on the thallus-margin and on the ventral surface of midrib; marginal hairs paired, single or in groups of three; male branches globose or subglobose; female involucres obovate and hirsute at the margin, calyptra fleshy, pyriform to club-shaped, hirsute on the outer surface, hairs long and straight
Solvent-cast films of an elastin-like polymer fused to an antimicrobial peptide, ABP-CM4, exhibits high antibacterial activity against pseudomonas aeruginosa
The nosocomial infections grew significantly in the last years and became a worldwide problem. Antimicrobial peptides (AMPs) arise as a good treatment to these infections, since traditional antibiotics have become useless against resistant hospital strains. AMPs exhibit a broad range of antimicrobial activity but antitumoral and antiviral activities have also been found. AMPs are usually small, cationic molecules that occur as part of the innate defense mechanism in many organisms, even in microbes and virus. The combination of AMPs with recombinantly produced polymers, such as the Elastin-like Polymers (ELPs), inspired in the mammalian elastin, could improve medical equipment, such as catheters, to overcome infections and biofilms formation.
In this work we describe the cloning and recombinant production in Escherichia coli BL21(DE3) of ABP-CM4, a cationic AMP from Bombyx mori, fused to an ELP, consisting of 200 repeats of the pentamer VPAVG (A200). This ELP exhibits thermoresponsive properties, exploitable as a purification method. The morphological characteristics as well as its antibacterial activity of this hybrid polymer were studied as essential for the applicability in medical devices.
The ABP-CM4 gene was chemically synthesized, with the inclusion of a formic acid cleavage site, and fused in frame with the N-terminus of the gene coding A200. Production of the recombinant polymer in E. coli BL21(DE3) was achieved and purification was based on the use of the inverse transition cycling method.
Formic acid treatment allowed tag removal and obtention of the soluble protein. The hybrid polymer, CM4::A200, and the cleaved ABP-CM4 were tested for its antimicrobial activity in liquid form. Solvent-cast films of CM4::A200, using formic acid as solvent, were tested for the antibacterial activity against Pseudomonas aeruginosa comparing with A200 polymers containing different contents of positively charged aminoacids.
The hybrid polymer presented similar morphological and physicochemical features to A200. The cleaved recombinant ABP-CM4 and CM4::A200 showed low levels of inhibition against P. aeruginosa in the liquid form but, in the solvent-cast film form, the inhibition of growth of was almost 100%. This result reveals very good perspectives for the use of these polymers in the medical equipment.Fundação para a Ciência e a Tecnologia (FCT
Nanobastões porosos de CeO2-ZrOx decorados com nanopartículas de ouro para a catálise da reação de oxidação preferencial de monóxido de carbono
Orientador: Italo Odone MazaliDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de QuímicaResumo: Este trabalho traz uma nova classe de catalisadores para a reação de oxidação preferencial de monóxido de carbono (PROX-CO) baseados em nanobastões de céria decorados com nanopartículas de ouro na superfície. Uma síntese hidrotérmica com diversas vantagens tais como one-step, one-pot e fácil de purificar possibilitou a preparação de nanopartículas de céria com alto grau de pureza, além de tamanho e morfologia controlados. Um inédito processo de lixiviação baseado na exposição das nanopartículas a uma solução de ácido sulfúrico foi empregado, no qual os poros nativos dos nanobastões foram expandidos, melhorando a capacidade total de armazenamento de oxigênio (OSC) do material. Os resultados da espectroscopia de emissão óptica de plasma acoplada indutivamente (ICP-OES) revelaram que as condições de lixiviação ácida empregadas foram eficazes para expandir a estrutura dos poros sem comprometer a estrutura das facetas cristalinas dos nanobastões de céria e evitar sua dissolução. Além disso, os resultados de espectroscopia Raman confirmaram o aumento da concentração de vacâncias de oxigênio na amostra lixiviada. Os nanobastões também foram dopados com íons Zr (IV) por meio de uma por co-precipitação. Para completar o catalisador, nanopartículas de ouro foram depositadas na superfície do óxido por deposição-precipitação (DP), na qual HAuCl4, é depositado na superfície do óxido após um ajuste controlado do pH da solução para 3, precipitando Au(OH)3, e posteriormente ouro metálico depois de tratamento térmico tratamento com a superfície do suporte desempenhando um papel como agente de nucleação. Diferentes métodos para aumentar o pH da solução, como adição de NaOH e decomposição térmica da ureia e diferentes temperaturas de tratamento térmico foram empregados, o que levou a diferentes desempenhos catalíticos. Demonstrou-se que os catalisadores compostos pelos nanobastões lixiviados são catalisadores mais apropriados para a reação de PROX-CO, aumentando a conversão total de CO e diminuindo a temperatura de conversão máxima, o que é favorável para o uso potencial deste material como catalisador em células combustíveis. Os nanobastões dopados com Zr também foram determinados como suportes mais eficientes, o que foi atribuído à capacidade dos íons Zr(IV) de elevar a OSC do materialAbstract: This work brings a novel class of catalysts for the reaction of preferential oxidation of carbon monoxide (PROX-CO) based on ceria nanorods decorated with gold nanoparticles on the surface. A hydrothermal synthesis with several advantages such as a one-step, one-pot, low-cost and easy-to-purify process that enables the preparation of high purity ceria nanoparticles of controlled size and morphology. Afterward, a novel acid lixiviation process based on treating the nanoparticles with sulfuric acid solution was employed in which the native pores of ceria nanorods were expanded improving the total oxygen storage capacity (OSC) of the material, a physical-chemical property of utmost importance to understand chemisorption phenomena in catalysis. Inductively coupled plasma optical emission spectroscopy (ICP-OES) results revealed that the acid leaching conditions employed were effective to expand the pore structure without compromising the facets structure of ceria nanorods and avoiding their dissolution. Raman results confirmed the increase in oxygen vacancies concentration in the lixiviated sample of nanorods. Cerium nanorods were also successfully doped with Zr (IV) ions via a co-precipitation technique. In order to complete the nanohierarchy of the catalyst, gold nanoparticles were placed down onto the oxide surface by the deposition-precipitation (DP) method. In the methodology carried out in this work, gold precursor, HAuCl4, is brought out of the solution in the presence of a suspension onto the support by increasing the pH in order to precipitate Au(OH)3, which gives out metallic gold after thermal treatment. The surface of the support plays a role as a nucleating agent controlling. Different methods to increase the pH of the solution, such as addition of NaOH and thermal decomposition of urea and different annealing temperatures were employed, which led to different catalytic performances. The catalysts composed by lixiviated ceria nanorods were proved to be better for PROX-CO reaction as they increased the total CO conversion and decreased the maximum conversion temperature, which is appropriate for the potential use of this catalyst in fuel cells. The Zr-doped nanorods also were determined to be more effective which was attributed to the capacity of Zr (IV) to improve the oxygen vacancy concentration of the nanorodsMestradoQuimica InorganicaMestre em Química2018/07853-2FAPES
Physical and chemical optimization of a synthetic medium for Pichia pastoris growth
The methylotrophic yeast Pichia pastoris is widely used as a host strain for the production of a variety of heterologous proteins.
The basal salt medium (BSM) described by Invitrogen (2000) is one of the most broadly used media for this expression system, although it possesses many problems, namely unbalanced composition, salt precipitation and undesirable ionic strength. This medium also uses NH4OH simultaneously, as the nitrogen source and the pH corrector, fact that may be responsible for several growth constrains, namely nitrogen limitation and low protein productivity.ELASTM program - POCI 2010
(project POCI/CTM/57177/2004
Qualidade da imunidade passiva colostral e perfil de variação de proteínas séricas em bezerros neonatos
A imunidade adquirida pelos recém-nascidos é denominada passiva e no caso dos ruminantes a aquisição de anticorpos depende da ingestão e absorção de quantidades adequadas de imunoglobulinas do colostro. Este trabalho relaciona diferentes teores iniciais de proteção passiva adquirida com o comportamento das variáveis proteína total (PT) e imunoglobulina G séricas (IgG). Os teores séricos de IgG e PT foram avaliados em bezerras da raça Holandesa do nascimento até 60 dias de idade. Os animais foram agrupados de acordo com a concentração inicial de imunoglobulinas séricas adquiridas: grupo 1- animais com baixo nível de imunidade passiva (até 20 mg mL-1); grupo 2- animais com nível médio de imunidade passiva (de 20 a 30 mg mL-1) e grupo 3- animais com alto nível de imunidade passiva (acima de 30 mg mL-1). As amostras séricas foram analisadas quanto a proteína total pelo método de biureto e para quantificação de IgG foi utilizado o método de imunodifusão radial. Os teores séricos de IgG e PT foram avaliados em um delineamento experimental inteiramente casualizado em parcelas subdivididas no tempo. Para determinar o comportamento dessas variáveis ao longo do período experimental, foram traçadas regressões não-lineares pelo método de DUD, procedimento PROC NLIN do SAS. Nos animais com baixa aquisição inicial de anticorpos verificou-se uma produção de anticorpos mais precoce. Já para os animais com níveis adequados de anticorpos verificou-se uma fase de catabolismo prolongada das imunoglobulinas e um início mais tardio da síntese endógena de anticorpos. Independente dos níveis iniciais, as flutuações dos teores de IgG ocorreram em intervalo de concentrações fisiologicamente adequadas, ou seja de 20 a 25 mg mL-1.Immunity acquired by newborn animals is known as passive immunity, and for ruminants, antibody acquisition depends on the ingestion and absorption of adequate amounts of immunoglobulins from colostrum. This study relates different initial levels of acquired passive protection and serum total protein (TP) and immunoglobulin G (IgG). Serum immunoglobulin concentration and total protein were evaluated for female Holstein calves in the first sixty days of life. Animals were separated into three groups according to their initial level of passive immunity: group 1- animals with a low level of passive immunity (below 20 mg mL-1); group 2- animals with a medium level (between 20 and 30 mg mL-1), and group 3- animals with a high level (above 30 mg mL-1). Serum total protein was determined through the biuret method and IgG was determined by radial immunodiffusion. Data were analyzed as a completely randomized, split-plot statistical design. Fluctuation of the variables along the experimental period was determined through non-linear regression by the DUD method (PROC NLIN - Non Linear SAS). Animals with low antibody acquisition started to produce antibodies earlier, reflecting a compensatory synthesis. On the other hand, animals having adequate levels exhibited an extended period of immunoglobulin catabolism and the beginning of the endogenous phase was delayed. Regardless initial levels, the fluctuations in IgG contents occurred around adequate physiological concentrations, ranging from 20 to 25 mg mL-1
ASO Author Reflections: Impact of a Preoperative Home-Based Exercise Program on Quality of Life After Lung Cancer Resection
Surgical resection is the cornerstone of curative treatment for patients with lung cancer. Nevertheless, it often leads to functional limitations and symptoms of pain, fatigue, and dyspnea, which have a detrimental impact on patients’ health-related quality of life (HRQoL).info:eu-repo/semantics/publishedVersio
Nanotechnology solutions for controlled cytokine delivery: an applied perspective
Around 200 cytokines with roles in cell signaling have been identified and studied, with the vast majority belonging to the four-α-helix bundle family. These proteins exert their function by binding to specific receptors and are implicated in many diseases. The use of several cytokines as therapeutic targets has been approved by the FDA, however their rapid clearance in vivo still greatly limits their efficacy. Nano-based drug delivery systems have been widely applied in nanomedicine to develop safe, specific and controlled delivery techniques. Nevertheless, each nanomaterial has its own specifications and their suitability towards the biochemical and biophysical properties of the selected drug needs to be determined, weighing in the final choice of the ideal nano drug delivery system. Nanoparticles remain the most used vehicle for cytokine delivery, where polymeric carriers represent the vast majority of the studied systems. Liposomes and gold or silica nanoparticles are also explored and discussed in this review. Additionally, surface functionalization is of great importance to facilitate the attachment of a wide variety of molecules and modify features such as bioavailability. Since the monitoring of cytokine levels has an important role in early clinical diagnosis and for assessing therapeutic efficacy, nanotechnological advances are also valuable for nanosensor development.This work was supported by the “Contrato-Programa” UIDB/04050/2020 funded by national
funds through the FCT I.P. and project FUN2CYT: Harnessing the potential for biomedical applications of
pleiotropic cytokines LIF and oncostatin M (POCI-01-0145-FEDER-030568) supported by Programa Operacional Competitividade e Internacionalização (FEDER) and FCT, IP. Anabela Gonçalves acknowledges her PhD scholarship from FCT (SFRH/BD/146807/2019)
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