19,008 research outputs found

    Determining the location of the α-synuclein dimer Interface using native top-down fragmentation and isotope depletion-mass spectrometry

    Get PDF
    α-Synuclein (αSyn), a 140-residue intrinsically disordered protein, comprises the primary proteinaceous component of pathology-associated Lewy body inclusions in Parkinson’s disease (PD). Due to its association with PD, αSyn is studied extensively; however, the endogenous structure and physiological roles of this protein are yet to be fully understood. Here, ion mobility-mass spectrometry and native top-down electron capture dissociation fragmentation have been used to elucidate the structural properties associated with a stable, naturally occurring dimeric species of αSyn. This stable dimer appears in both wild-type (WT) αSyn and the PD-associated variant A53E. Furthermore, we integrated a novel method for generating isotopically depleted protein into our native top-down workflow. Isotope depletion increases signal-to-noise ratio and reduces the spectral complexity of fragmentation data, enabling the monoisotopic peak of low abundant fragment ions to be observed. This enables the accurate and confident assignment of fragments unique to the αSyn dimer to be assigned and structural information about this species to be inferred. Using this approach, we were able to identify fragments unique to the dimer, which demonstrates a C-terminal to C-terminal interaction between the monomer subunits. The approach in this study holds promise for further investigation into the structural properties of endogenous multimeric species of αSyn

    Anuário científico da Escola Superior de Tecnologia da Saúde de Lisboa - 2021

    Get PDF
    É com grande prazer que apresentamos a mais recente edição (a 11.ª) do Anuário Científico da Escola Superior de Tecnologia da Saúde de Lisboa. Como instituição de ensino superior, temos o compromisso de promover e incentivar a pesquisa científica em todas as áreas do conhecimento que contemplam a nossa missão. Esta publicação tem como objetivo divulgar toda a produção científica desenvolvida pelos Professores, Investigadores, Estudantes e Pessoal não Docente da ESTeSL durante 2021. Este Anuário é, assim, o reflexo do trabalho árduo e dedicado da nossa comunidade, que se empenhou na produção de conteúdo científico de elevada qualidade e partilhada com a Sociedade na forma de livros, capítulos de livros, artigos publicados em revistas nacionais e internacionais, resumos de comunicações orais e pósteres, bem como resultado dos trabalhos de 1º e 2º ciclo. Com isto, o conteúdo desta publicação abrange uma ampla variedade de tópicos, desde temas mais fundamentais até estudos de aplicação prática em contextos específicos de Saúde, refletindo desta forma a pluralidade e diversidade de áreas que definem, e tornam única, a ESTeSL. Acreditamos que a investigação e pesquisa científica é um eixo fundamental para o desenvolvimento da sociedade e é por isso que incentivamos os nossos estudantes a envolverem-se em atividades de pesquisa e prática baseada na evidência desde o início dos seus estudos na ESTeSL. Esta publicação é um exemplo do sucesso desses esforços, sendo a maior de sempre, o que faz com que estejamos muito orgulhosos em partilhar os resultados e descobertas dos nossos investigadores com a comunidade científica e o público em geral. Esperamos que este Anuário inspire e motive outros estudantes, profissionais de saúde, professores e outros colaboradores a continuarem a explorar novas ideias e contribuir para o avanço da ciência e da tecnologia no corpo de conhecimento próprio das áreas que compõe a ESTeSL. Agradecemos a todos os envolvidos na produção deste anuário e desejamos uma leitura inspiradora e agradável.info:eu-repo/semantics/publishedVersio

    Ruthenium (II) polypyridyl complexes as photoprobes for DNA mismatches

    Get PDF
    [Ru(bpy)2dppz]2+ is a classic “light switch” effect complex with a brighter emission for mismatched DNA than well-matched DNA. It is, therefore, a photoprobe for DNA. To enhance its selectivity for mismatched base pairs which can lead to DNA mutations, a range of related complexes were synthesized and investigated. The approach involved increasing the steric bulk of the ancillary 2,2’-bipyridine (bpy) ligands and/or the dipyridophenazine (dppz) functional group ligand. This functional group ligand is known to insert or intercalate between adjacent base pairs in the base stack of DNA and an alternative functional group ligand was also explored: 12,17-dihydronaphthodipyridophenazine-12,17-dione (aqphen). Hairpin and 12 base oligonucleotide duplex DNA containing mismatched base pairs were tested and compared to the same sequences containing well-matched base pairs. Methylation of the ancillary bpy ligands only at positions 5,5’ with dppz as the functional group ligand is highly selective for both the CC and the TT mismatches. For the former the signal is between 4 and 6.3x higher than it is for well-matched DNA and for the latter a 6x increase was recorded. It almost certainly binds to the DNA via intercalation and its performance in these experiments have identified a useful photoprobe for the identification of these mismatched base pairings. Methylation of the dppz functional group ligand at positions 10 and 12 produced large increases in emission intensity compared to the parent compound [Ru(bpy)2dppz]2+ but did not substantially increase the mismatch base pair selectivity. The use of aqphen instead of dppz as the functional group ligand increased the binding strength with DNA and, notably, it showed a higher binding affinity for a 12mer duplex containing a CC mismatched base pair versus the well-matched sequence; its mode of binding is likely to be intercalation. In summary, enhancing steric bulk through methylation of the ancillary bpy ligands has achieved the desired selectivity whilst the same modification to the inserting dppz functional group ligand has led to large increases in signal intensity without an improvement in selectivity. The use of aqphen as the functional group ligand, which also has a greater steric bulk compared to dppz, increased binding affinity as well as selectivity

    Drug Delivery Applications of Metal-Organic Frameworks (MOFs)

    Get PDF
    There has been substantial progress in the field of metal–organic frameworks (MOFs) and their nanoscale counterparts (NMOFs), in recent years. Their exceptional physicochemical properties are being constantly and actively exploited for various applications such as energy harvesting, gas storage, gas separation, catalysis, etc. Due to their porous framework, large surface area, tunability and easy surface functionalization, MOFs and NMOFs have also emerged as useful tools for biomedical applications, specifically for drug delivery. As drug carriers, they offer high drug loading capacity and controlled release at the target site. This chapter aims to give a panorama of the use of these MOFs as drug delivery agents. A brief overview of the structure and composition of MOFs, along with various methods and techniques to synthesize NMOFs suitable for drug delivery applications are mentioned. In addition, the most commonly employed strategies to associate drugs with these NMOFs are highlighted and methods to characterize them are also briefly discussed. The last section summarizes the applications of MOFs and NMOFs as carriers of therapeutic drugs, biomolecules, and other active agents

    Bioactive Compounds from Marine Heterobranchs

    Get PDF
    The natural products of heterobranch molluscs display a huge variability both in structure and in their bioactivity. Despite the considerable lack of information, it can be observed from the recent literature that this group of animals possesses an astonishing arsenal of molecules from different origins that provide the molluscs with potent chemicals that are ecologically and pharmacologically relevant. In this review, we analyze the bioactivity of more than 450 compounds from ca. 400 species of heterobranch molluscs that are useful for the snails to protect themselves in different ways and/or that may be useful to us because of their pharmacological activities. Their ecological activities include predator avoidance, toxicity, antimicrobials, antifouling, trail-following and alarm pheromones, sunscreens and UV protection, tissue regeneration, and others. The most studied ecological activity is predation avoidance, followed by toxicity. Their pharmacological activities consist of cytotoxicity and antitumoral activity; antibiotic, antiparasitic, antiviral, and anti-inflammatory activity; and activity against neurodegenerative diseases and others. The most studied pharmacological activities are cytotoxicity and anticancer activities, followed by antibiotic activity. Overall, it can be observed that heterobranch molluscs are extremely interesting in regard to the study of marine natural products in terms of both chemical ecology and biotechnology studies, providing many leads for further detailed research in these fields in the near future

    Estudo da remodelagem reversa miocárdica através da análise proteómica do miocárdio e do líquido pericárdico

    Get PDF
    Valve replacement remains as the standard therapeutic option for aortic stenosis patients, aiming at abolishing pressure overload and triggering myocardial reverse remodeling. However, despite the instant hemodynamic benefit, not all patients show complete regression of myocardial hypertrophy, being at higher risk for adverse outcomes, such as heart failure. The current comprehension of the biological mechanisms underlying an incomplete reverse remodeling is far from complete. Furthermore, definitive prognostic tools and ancillary therapies to improve the outcome of the patients undergoing valve replacement are missing. To help abridge these gaps, a combined myocardial (phospho)proteomics and pericardial fluid proteomics approach was followed, taking advantage of human biopsies and pericardial fluid collected during surgery and whose origin anticipated a wealth of molecular information contained therein. From over 1800 and 750 proteins identified, respectively, in the myocardium and in the pericardial fluid of aortic stenosis patients, a total of 90 dysregulated proteins were detected. Gene annotation and pathway enrichment analyses, together with discriminant analysis, are compatible with a scenario of increased pro-hypertrophic gene expression and protein synthesis, defective ubiquitinproteasome system activity, proclivity to cell death (potentially fed by complement activity and other extrinsic factors, such as death receptor activators), acute-phase response, immune system activation and fibrosis. Specific validation of some targets through immunoblot techniques and correlation with clinical data pointed to complement C3 β chain, Muscle Ring Finger protein 1 (MuRF1) and the dual-specificity Tyr-phosphorylation regulated kinase 1A (DYRK1A) as potential markers of an incomplete response. In addition, kinase prediction from phosphoproteome data suggests that the modulation of casein kinase 2, the family of IκB kinases, glycogen synthase kinase 3 and DYRK1A may help improve the outcome of patients undergoing valve replacement. Particularly, functional studies with DYRK1A+/- cardiomyocytes show that this kinase may be an important target to treat cardiac dysfunction, provided that mutant cells presented a different response to stretch and reduced ability to develop force (active tension). This study opens many avenues in post-aortic valve replacement reverse remodeling research. In the future, gain-of-function and/or loss-of-function studies with isolated cardiomyocytes or with animal models of aortic bandingdebanding will help disclose the efficacy of targeting the surrogate therapeutic targets. Besides, clinical studies in larger cohorts will bring definitive proof of complement C3, MuRF1 and DYRK1A prognostic value.A substituição da válvula aórtica continua a ser a opção terapêutica de referência para doentes com estenose aórtica e visa a eliminação da sobrecarga de pressão, desencadeando a remodelagem reversa miocárdica. Contudo, apesar do benefício hemodinâmico imediato, nem todos os pacientes apresentam regressão completa da hipertrofia do miocárdio, ficando com maior risco de eventos adversos, como a insuficiência cardíaca. Atualmente, os mecanismos biológicos subjacentes a uma remodelagem reversa incompleta ainda não são claros. Além disso, não dispomos de ferramentas de prognóstico definitivos nem de terapias auxiliares para melhorar a condição dos pacientes indicados para substituição da válvula. Para ajudar a resolver estas lacunas, uma abordagem combinada de (fosfo)proteómica e proteómica para a caracterização, respetivamente, do miocárdio e do líquido pericárdico foi seguida, tomando partido de biópsias e líquidos pericárdicos recolhidos em ambiente cirúrgico. Das mais de 1800 e 750 proteínas identificadas, respetivamente, no miocárdio e no líquido pericárdico dos pacientes com estenose aórtica, um total de 90 proteínas desreguladas foram detetadas. As análises de anotação de genes, de enriquecimento de vias celulares e discriminativa corroboram um cenário de aumento da expressão de genes pro-hipertróficos e de síntese proteica, um sistema ubiquitina-proteassoma ineficiente, uma tendência para morte celular (potencialmente acelerada pela atividade do complemento e por outros fatores extrínsecos que ativam death receptors), com ativação da resposta de fase aguda e do sistema imune, assim como da fibrose. A validação de alguns alvos específicos através de immunoblot e correlação com dados clínicos apontou para a cadeia β do complemento C3, a Muscle Ring Finger protein 1 (MuRF1) e a dual-specificity Tyr-phosphoylation regulated kinase 1A (DYRK1A) como potenciais marcadores de uma resposta incompleta. Por outro lado, a predição de cinases a partir do fosfoproteoma, sugere que a modulação da caseína cinase 2, a família de cinases do IκB, a glicogénio sintase cinase 3 e da DYRK1A pode ajudar a melhorar a condição dos pacientes indicados para intervenção. Em particular, a avaliação funcional de cardiomiócitos DYRK1A+/- mostraram que esta cinase pode ser um alvo importante para tratar a disfunção cardíaca, uma vez que os miócitos mutantes responderam de forma diferente ao estiramento e mostraram uma menor capacidade para desenvolver força (tensão ativa). Este estudo levanta várias hipóteses na investigação da remodelagem reversa. No futuro, estudos de ganho e/ou perda de função realizados em cardiomiócitos isolados ou em modelos animais de banding-debanding da aorta ajudarão a testar a eficácia de modular os potenciais alvos terapêuticos encontrados. Além disso, estudos clínicos em coortes de maior dimensão trarão conclusões definitivas quanto ao valor de prognóstico do complemento C3, MuRF1 e DYRK1A.Programa Doutoral em Biomedicin

    Starch hydrogels as targeted colonic drug delivery vehicles

    Get PDF
    Targeted colonic drug delivery systems are needed for the treatment of endemic colorectal pathologies, such as Crohn's disease, ulcerative colitis, and colorectal cancer. These drug delivery vehicles are difficult to formulate, as they need to remain structurally intact whilst navigating a wide range of physiological conditions across the upper gastrointestinal tract. In this work we show how starch hydrogel bulk structural and molecular level parameters influence their properties as drug delivery platforms. The in vitro protocols mimic in vivo conditions, accounting for physiological concentrations of gastrointestinal hydrolytic enzymes and salts. The structural changes starch gels undergo along the entire length of the human gastrointestinal tract have been quantified, and related to the materials' drug release kinetics for three different drug molecules, and interactions with the large intestinal microbiota. It has been demonstrated how one can modify their choice of starch in order to fine tune its corresponding hydrogel's pharmacokinetic profile

    Circularly Polarized Luminescence of [6]Helicenes through Excited- State Intramolecular Proton Transfer

    Get PDF
    This project received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreements No. 716139 and No. 677023), the Swiss National Science Foundation (SNSF, PP00P2_170534, PP00P2_198900), Project PGC2018-101181-B-I00 funded by MCIN/AEI/ 10.13039/501100011033 FEDER "Una manera de hacer Europa", grant A-FQM-230-UGR20 funded by FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades and the German Academic Exchange Service (DAAD, postdoc fellowship to D. G.). Open access funding provided by the University of Zurich.We present the concept of combining circularly polarized luminescence (CPL) and excited-state intramolecular proton transfer (ESIPT) features into a single molecule as a strategy to generate high-performance ESIPT-based CPL materials. For this purpose, a [6]helicene bearing two ESIPT structural units was synthesized using a double Suzuki-Miyaura reaction and a double C(sp(2))-H hydroxylation approach. The photophysical properties of the doubly hydroxylated [6]helicene were studied in parallel with a non-hydroxylated [6]helicene control compound, revealing that the presence of a chiral [6]helicene unit results in a strong CPL response and the presence of the ESIPT units in a considerable red shift. The red-shifted emission along with the outstanding g(lum) (approximate to 10(-2)) and a large Stokes shift makes the doubly hydroxylated [6]helicene a promising candidate for use in optoelectronics.European Research Council (ERC) 716139 677023Swiss National Science Foundation (SNSF) PP00P2_170534 PP00P2_198900Deutscher Akademischer Austausch Dienst (DAAD)University of ZurichMCIN/AEI FEDER "Una manera de hacer Europa" PGC2018-101181-B-I00FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades A-FQM-230-UGR2

    Desarrollo de materiales bioactivos con potencial aplicación odontológica mediante impregnación asistida por CO2 supercrítico

    Get PDF
    Tesis (DCI)--FCEFN-UNC, 2021En esta tesis se estudió el proceso de incorporación de eugenol en fibras de poliamida 6 (PA6) mediante la impregnación asistida por CO2 supercrítico para desarrollar un material con propiedades antimicrobianas con una potencial aplicación odontológica. Para este propósito, se construyó un equipo de alta presión en el que se llevaron a cabo múltiples ensayos de impregnación de eugenol y de sorción de CO2 en un hilo dental comercial de PA6 en distintas condiciones de presión y temperatura (40 – 60 °C y 8 – 12 MPa). Con el fin de encontrar las mejores condiciones del proceso de impregnación, se evaluó la influencia de diferentes variables operativas (presión, temperatura, tiempo de contacto y velocidad de despresurización) sobre la cantidad de eugenol impregnada en el material. Además, se estudiaron los principales fenómenos difusivos que ocurren en el proceso de impregnación del eugenol en condiciones supercríticas. Para ello, se hicieron ensayos de cinética de sorción del CO2 y del eugenol en PA6 a diferentes condiciones de presión y temperatura y se determinó el coeficiente de difusión aparente para ambas especies en este polímero. Por otra parte, se evaluaron las propiedades finales del material impregnado, analizando las propiedades mecánicas, térmicas y morfológicas del material original, presurizado con CO2 e impregnado con eugenol. Adicionalmente se evaluó la actividad antimicrobiana del material impregnado frente a dos bacterias comunes (Escherichia coli y Staphylococcus aureus). Asimismo, se estudió la migración del compuesto activo impregnado en aire y en saliva artificial, obteniendo datos importantes para el potencial desarrollo de un producto comercial, como la estimación de la vida útil, el tipo de envase, y tipo de aplicación del producto. Finalmente, se hizo un diseño y dimensionamiento de un proceso industrial para la impregnación de eugenol en bobinas de fibras de PA6 en CO2 supercrítico, a partir de los datos de eficiencia de impregnación y parámetros difusivos del hilo impregnado con eugenol previamente obtenidos, realizando el diseño de la bobina, el equipo impregnador y los cálculos de sus principales requerimientos de masa y energía.Fil: Mosquera Ruiz, José Euliser. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Mosquera Ruiz, José Euliser. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; Argentina
    corecore