Nanoparticles as a tool in capillary electrochromatography

Two different types of molecularly imprinted nanoparticles against (R)-propranolol were used to separate the enantiomers of propranolol in capillary electrochromatography mode, methacrylic acid based nanoparticles and core-shell molecularly imprinted polymer nanoparticles. Partial filling technique was used to avoid interference of molecularly imprinted polymer nanoparticles in UV detection. With methacrylic acid based nanoparticles it was not possible to obtain enantiomer separation. Strong unspecific interactions between the molecular imprinted polymer nanoparticles and propranolol disturbed enantiomer separation. Since large content of acetonitrile had to be used in order to obtain stable suspensions of molecularly imprinted polymer nanoparticles, the electrostatic interactions were favored which contributed to the unspecific interactions occurring. Core-shell molecularly imprinted polymer nanoparticles present suspension stability at low content of acetonitrile due to the poly(acrylamide) shell that makes them more hydrophilic. Enantiomer separation of propranolol was achieved with 40% of acetonitrile. Reproducibility was problematic due to the unspecific interactions occurring. With time several factors can occur contributing to the decreased reproducibility of results such as, interactions between the molecularly imprinted polymer nanoparticles and the capillary wall or evaporation of the organic solvent due to the design of vials used in capillary electrochromatography system. The core-shell molecularly imprinted polymer nanoparticles are more suitable for propranolol enantiomer separation in comparison to methacrylic acid based nanoparticles. More stable suspensions give a greater range of conditions that can be tested. Silanized gadolinium oxide nanoparticles were tested as pseudostationary phase in capillary electrochromatography for protein separation. The lack of interference with UV detection and the large surface area of these nanoparticles make them a promising tool in capillary electrochromatography for protein separation. These nanoparticles interact with the proteins that are analyzed. Increased injection times of the nanoparticles give retained peaks of human growth hormone showing that strong interactions between the protein and nanoparticles are occurring. Lysozyme that was not recovered using conventional capillary electrophoresis could be detected when nanoparticles were used as pseudostationary phase. The nanoparticles can act as a coating in the capillary wall or due to their large surface area they can prevent adsorption of the lysozyme to the capillary.Dois tipos diferentes de nanopartículas impressas molecularmente, selectivas de (R) – propranolol, foram utilizadas para a separação dos enantiomeros de propranolol em electrocromatografia capilar ( nanopartículas à base de ácido metacrílico e nanopartículas revestidas com poliacrilamida). Para evitar interferência das nanopartículas com a detecção UV a técnica de preenchimento parcial foi utilizada. Com as nanopartículas à base de ácido metacrílico a separação dos enantiomeros de propranolol não foi alcançada. Interacções fortes inespecíficas entre as nanopartículas e o propronolol impossibilitaram a separação. Para obter suspensões estáveis de nanopartículas à base de ácido metacrílico elevadas quantidades de acetonitrilo foram utilizadas, favorecendo interacções eletrostáticas que contribuiram para o aumento das interacções inespecíficas. As nanopartículas revestidas com poliacrilamida apresentam suspensões estáveis com baixas quantidades de acetonitrilo, devido as propriedades hidrofílicas da poliacrilamida. A separação dos enantiomeros de propranolol foi alcançada com 40% de acetonitrilo. As interacções inespecíficas foram um factor dominante na irreproducibilidade dos resultados. Com o tempo vários factores contribuem para a diminuição da reproducibilidade dos resultados como por exemplo: interacções entre as nanopartículas e a parede do capilar e a evaporação do solvente orgânico devido ao design dos tubos de ensaio utilizados na electrocromatografia capilar. As nanopartículas revestidas com poliacrilamida säo mais adequadas para a separação dos enantiomeros de propranolol devido á elevada estabilidade de suspensöes apresentada em diferentes condições. Nanopartículas de gadolínio silanizadas foram testadas como fase pseudoestacionária em electrocromatografia capilar. Características como a não detecção em UV e a grande área de superfície tornam estas nanopartículas de grande interesse para a separação de proteínas. A hormona de crescimento e a lisozima foram as proteínas analisadas. A hormona de crescimento apresenta picos mais retidos quando se aumenta os tempos de injecção das nanopartículas, mostrando que interacções entre a proteína e as nanopartículas ocorrem. A utilização destas nanopartículas como fase pseudoestacionária permitiu a detecção da lisozima que não é visível utilizando electroforese capilar convencional. A adsorção da lisozima à parede do capilar é evitada devido ao uso destas nanopartículas

Propriedades tecnológicas e probióticas das bactérias isoladas do queijo do Pico

A secção Biologia é coordenada pelo Professor Universitário Armindo Rodrigues.[…]. A listéria é o agente patogénico responsável pela listeriose, uma infeção rara, mas grave nos seres humanos. Leite e produtos lácteos têm sido implicados na maioria dos surtos relatados de listeriose, embora o tratamento térmico elimine esta bactéria durante o processo de pasteurização. Isto indica que estes produtos podem ser contaminados em fases posteriores de produção. Desta forma, a contaminação do queijo com listéria é um problema recorrente e uma preocupação constante para a indústria dos lacticínios. A utilização de bactérias que possam combater este agente patogénico pode ser uma mais-valia na aplicação a este tipo de produtos. Assim, um dos grandes objetivos consiste em identificar novas estirpes com atividade antimicrobiana para utilização na produção de queijos mais seguros e de melhor qualidade. […].info:eu-repo/semantics/publishedVersio

A comprehensive assessment of the transcriptome of cork oak (Quercus suber) through EST sequencing

Background: Cork oak (Quercus suber) is one of the rare trees with the ability to produce cork, a material widely used to make wine bottle stoppers, flooring and insulation materials, among many other uses. The molecular mechanisms of cork formation are still poorly understood, in great part due to the difficulty in studying a species with a long life-cycle and for which there is scarce molecular/genomic information. Cork oak forests are of great ecological importance and represent a major economic and social resource in Southern Europe and Northern Africa. However, global warming is threatening the cork oak forests by imposing thermal, hydric and many types of novel biotic stresses. Despite the economic and social value of the Q. suber species, few genomic resources have been developed, useful for biotechnological applications and improved forest management. Results: We generated in excess of 7 million sequence reads, by pyrosequencing 21 normalized cDNA libraries derived from multiple Q. suber tissues and organs, developmental stages and physiological conditions. We deployed a stringent sequence processing and assembly pipeline that resulted in the identification of ~159,000 unigenes. These were annotated according to their similarity to known plant genes, to known Interpro domains, GO classes and E.C. numbers. The phylogenetic extent of this ESTs set was investigated, and we found that cork oak revealed a significant new gene space that is not covered by other model species or EST sequencing projects. The raw data, as well as the full annotated assembly, are now available to the community in a dedicated web portal at http://www.corkoakdb.org. Conclusions: This genomic resource represents the first trancriptome study in a cork producing species. It can be explored to develop new tools and approaches to understand stress responses and developmental processes in forest trees, as well as the molecular cascades underlying cork differentiation and disease response.Peer Reviewe

Isolation and characterization of bioactive compounds produced by lactic acid bacteria

Tese de Doutoramento, Ciências Agrárias, especialidade de Tecnologia Alimentar, 02 de maio de 2018, Universidade dos Açores.A caracterização de queijos tradicionais, em especial os de denominação de origem protegida, é extremamente importante, não só para a obtenção do produto final desejável, mas também de um ponto de vista económico e até ecológico. Estes queijos fabricados com leite cru são uma fonte crucial de bactérias do ácido láctico (BAL) geneticamente diversificada, que podem apresentar características promotoras de saúde e tecnológicas relevantes. Desta forma, 114 BAL isoladas de um queijo tradicional Açoriano (queijo do Pico) foram avaliadas pelo seu potencial em produzir compostos bioativos que podem ser benéficos para a saúde e para a segurança do produto final. As características tecnológicas destes isolados foram igualmente estudadas, tendo em mente o desenvolvimento de produtos funcionais com aplicações industriais. Os isolados de BAL foram primeiramente analisados pela sua capacidade de produzir substâncias antimicrobianas, bacteriocinas, contra várias bactérias patogénicas. […]. Em conclusão, o presente trabalho demonstrou o potencial de algumas estirpes de BAL isoladas do queijo do Pico, em produzir compostos bioactivos com relevância para serem utilizados no desenvolvimento de produtos alimentares funcionais.ABSTRACT: Characterization of traditional cheeses, namely those with Protected Designation of Origin (PDO) status, is of extremely importance, not only for maintaining the quality of the end product, but also for economic and even ecologic reasons. These raw milk cheeses are considered a crucial source of lactic acid bacteria (LAB), genetically diversified, that can offer particular, health promoting and technological features. So, 114 LAB isolated from a traditional Azorean cheese (Pico cheese), were studied for their potential to produce bioactive compounds that can display safety and health benefits. Technological features were also evaluated, having in mind the development of functional food products and further industrial applications. The LAB isolates were firstly screened for production of antimicrobial substances, bacteriocins, against a group of pathogenic bacteria. […]. Overall, the present work demonstrated the potential of several LAB strains isolated from Pico cheese to produce bioactive compounds with high potential to be use in the development of functional foods

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)