Energy transduction by respiratory complex I

Dissertation presented to obtain a PhD degree in Biochemistry at the Instituto de Tecnologia Química e Biológica, Universidade Nova de LisboaThe aim of the work presented in this dissertation was to provide a contribution to the understanding of the energy transducing mechanism of respiratory complex I. This enzyme is present in most bacteria and in all mitochondrial systems and it is characterized by its large number of subunits, its prosthetic groups (flavin and iron-sulfur centers), and its NADH:quinone oxidoreductase activity sensitive to specific inhibitors and coupled with charge translocation across the membrane.(...

Drought response of cowpea (Vigna unguiculata (L.) Walp.) landraces at leaf physiological and metabolite profile levels

Drought threatens the world’s food production, particularly in Sub Saharan Africa low external input and rain fed agricultural systems, where cowpea (Vigna unguiculata (L.) Walp.) is an important food crop. In the context of growing concerns regarding climate changes implications on water availability, this study aimed at 1) to evaluate the drought responses in cowpea landraces with contrasting drought tolerance levels (A55 – high sensitivity; A80 - mild sensitivity; A116 - tolerant), 2) using an integrated physiological (leaf gas exchanges; chlorophyll a fluorescence) and biochemical (photoprotective pigments; RuBisCO activity; primary metabolite profiling) analysis to identify drought tolerance probes, in plants submitted to three water availability levels (well-watered, WW; mild drought, MD; severe drought, SD). A116 plants maintained a better water status under drought, what could justify the higher Pn and Pnmax values in MD, as well as higher photochemical use of energy (reflected in the photochemical quenching (qL) and in the quantum yield of non-cyclic electron transport (Y(II))), and the lower need of photoprotective thermal dissipation mechanisms (given by the non-photochemical quenching (qN), and the quantum yield of regulated energy dissipation at photosystem PSII (Y(NPQ))), in MD and SD plants. Greater declines of net (Pn) and potential (Pnmax) photosynthesis were observed in A55 plants, which frequently showed significant impacts already under MD conditions in most parameters, whereas A80 usually displayed and intermediate behaviour. Still, even A55 showed some acclimation response, regarding photoprotective mechanisms associated with high contents of zeaxanthin, lutein, and carotenes, and high Y(NPQ), and qN values, supporting the absence of an increase in the non-regulated energy dissipation at PSII (Y(NO) did not increased) even in SD plants. Additionally, A55 was not significantly affected in RuBisCO activity, which showed to be quite resilient in cowpea. A primary metabolite profiling, complemented with a partial least square discrimination analysis (PLS-DA), allowed a better separation of A116 and A55 plants according to their degree of drought tolerance. In response to drought, A116 showed the greatest accumulation of most responsive metabolites, 14 in total, with sucrose, fucose, urea, alanine and putrescine being exclusively increased in this genotype, suggesting that they can be candidates as drought tolerance proxies. Other compounds, as proline, valine, isoleucine (among amino acids), and rhamnose and raffinose (among sugars) showed close increase patternsinfo:eu-repo/semantics/publishedVersio

Improving land cover classification using genetic programming for feature construction

Batista, J. E., Cabral, A. I. R., Vasconcelos, M. J. P., Vanneschi, L., & Silva, S. (2021). Improving land cover classification using genetic programming for feature construction. Remote Sensing, 13(9), [1623]. https://doi.org/10.3390/rs13091623Genetic programming (GP) is a powerful machine learning (ML) algorithm that can produce readable white-box models. Although successfully used for solving an array of problems in different scientific areas, GP is still not well known in the field of remote sensing. The M3GP algorithm, a variant of the standard GP algorithm, performs feature construction by evolving hyperfeatures from the original ones. In this work, we use the M3GP algorithm on several sets of satellite images over different countries to create hyperfeatures from satellite bands to improve the classification of land cover types. We add the evolved hyperfeatures to the reference datasets and observe a significant improvement of the performance of three state-of-the-art ML algorithms (decision trees, random forests, and XGBoost) on multiclass classifications and no significant effect on the binary classifications. We show that adding the M3GP hyperfeatures to the reference datasets brings better results than adding the well-known spectral indices NDVI, NDWI, and NBR. We also compare the performance of the M3GP hyperfeatures in the binary classification problems with those created by other feature construction methods such as FFX and EFS.publishersversionpublishe

Extraction of Biocompatible Collagen From Blue Shark Skins Through the Conventional Extraction Process Intensification Using Natural Deep Eutectic Solvents

ERC-2016-CoG 725034The disposal of large amounts of skin waste resulting from the blue shark fishing industry presents several industrial and environmental waste management concerns. In addition, these marine subproducts are interesting sources of collagen, a fibrous protein that shows high social and economic interest in a broad range of biomedical, pharmaceutical, and cosmetic applications. However, blue shark wasted skins are a poorly explored matrix for this purpose, and conventional collagen recovery methodologies involve several pre-treatment steps, long extraction times and low temperatures. This work presents a new green and sustainable collagen extraction approach using a natural deep eutectic solvent composed of citric acid:xylitol:water at a 1:1:10 molar ratio, and the chemical characterization of the extracted collagen by discontinuous electrophoresis, thermogravimetric analysis, Fourier transformed infrared spectroscopy and circular dichroism. The extracted material was a pure type I collagen, and the novel approach presented an extraction yield 2.5 times higher than the conventional one, without pre-treatment of raw material and reducing the procedure time from 96 to 1 h. Furthermore, the in vitro cytotoxicity evaluation, performed with a mouse fibroblasts cell line, has proven the biocompatibility of the extracted material. Overall, the obtained results demonstrate a simple, quick, cheap and environmentally sustainable process to obtain marine collagen with promising properties for biomedical and cosmetic applications.publishersversionpublishe

Physicochemical characterization of psyllium fiber

Psyllium is the common name used for several members of the plant genus Plantago, whose seeds are commercially used for mucilage production. Owing to its considerable fiber amount it has been used as dietary fiber supplement. Psyllium has a strong gelling ability, even at low temperature, enabling its use as a gelling agent in the food industry. This work is part of a project to developing jellies enriched with fiber, honey and propolis, aiming to increase these products intake, with evident health benefits. The chemical characterization of psyllium was performed, with the following results (in dry matter): total ash 2.5%, fat content 3.4% and total protein 1.4%. After qualitative acid hydrolysis polymeric sugars were quantified (in dry matter): glucan 7.3%, xylan 61.1% and arabinan 22.9%. This means that total fiber content is about 90%, being soluble fiber predominant, and allows classifying psyllium hemicellulose as an arabinoxylan. Psyllium functional properties were evaluated by water-binding capacity and swelling determination: 27.1 g/g and 36.9 ml/g, respectively. These properties are important in the food industry, but under certain circumstances may limit the food type that can be enriched with this fiber. An important part of the research consisted on the characterization of gels viscoelastic behavior and texture, which were prepared with different psyllium particle dimension (raw and ground) and concentration (2.0%, 2.5% and 3.0%). The Response Surface Methodology was used to study the effect of process conditions (time and temperature) on texture and color characteristics of gels. Texture properties of gels were evaluated by Texture Profile Analysis. Gels dynamic behaviour was studied by a sequence of oscillatory measurements of temperature, time and frequency sweeps. Psyllium gelling properties were improved with the reduction of the fiber particle dimension. Gels revealed potential viscoelastic properties that might be interesting in the industrial purpose of honey jelly production

Fortalezas del carácter y autorregulación emocional en trabajadores brasileños

Character strengths and emotion self-regulation are relevant psychological resources to help workers cope with current demands in the workplace. The present investigation aimed to test the association with and the predictive power of the character strengths regarding emotion self-regulation. A total of 203 participants aged 18 to 68 years answered the sociodemographic questionnaire, Character Strength Scale –Brief (CSS-Brief), and the Emotion Self-Regulation Scale –Adult (ESRS-AD). The findings indicated weak to strong associations between the CSS-Brief and ESRS-AD factors. The intrapersonal strength and the intellectual and interpersonal strengths predicted the emotion self-regulation strategies likely to be adopted by the workers. The gathered evidence suggested significant differences in the ESRS-AD and CSS-Brief regarding the participants’ sociodemographic features. These results have occurred regardless of the workers’ hierarchical level and job department.Las fortalezas del carácter y la autorregulación de las emociones son recursos psicológicos relevantes para ayudar a los trabajadores a hacer frente a las demandas actuales en trabajo. La presente investigación tuvo como objetivo probar la asociación y el poder predictivo de las fortalezas del carácter con respecto a la autorregulación emocional. Un total de 203 participantes con edades entre 18 y 68 años respondieron el cuestionario sociodemográfico, la Escala de Fortaleza del Carácter -Breve (EFC-Breve) y la Escala de Autorregulación Emocional -Adulto (EARE-AD). Los resultados indicaron asociaciones de débiles a fuertes entre los factores CSS-Brief y ESRS-AD. La fortaleza intrapersonal y las fortalezas intelectuales e interpersonales predijeron las estrategias de autorregulación emocional susceptibles de ser adoptadas por los trabajadores. La evidencia recopilada sugirió diferencias significativas en ESRS-AD y CSS-Brief con respecto a las características sociodemográficas de los participantes. Estos resultados se han producido independientemente del nivel jerárquico y del departamento de trabajo de los trabajadore

New fluorescent heterocyclic materials: Synthesis, solvatochromic and fluorescence properties

Thienyl- and bithienyl-1,3-benzothiazoles 1 and 2 were synthesised by reacting various formyl thienyl and bithienyl derivatives with o-aminobenzenethiol in moderate to excellent yields. Evaluation of the solvatochromic and fluorescence properties of these compounds was carried out. Due to their strong fluorescence and also the strong push-pull character, benzothiazole derivatives 1 and 2 can be used as potential NLO materials or as fluorescent markers.Fundação para a Ciência e Tecnologia (FCT

Production of the ragworm Nereis diversicolor (O. F. Müller, 1776), fed with a diet for gilthead seabream Sparus auratus L., 1758: survival, growth, feed utilization and oogenesis

A 65-day experiment was conducted to determine survival, growth, feed utilization and oogenesis of Nereis diversicolor (O. F. Müller, 1776), fed with a commercial dry diet developed for gilthead seabream Sparus auratus L., 1758. Worms were reared in three replicate tanks with 50 worms per tank (255 indiv · m_2). Tetramin®, a commonly used diet for ornamental fish and polychaete laboratory experiments, was used as a control. Survival was high (95.3 %) for both treatments, and not significantly affected by diet. Specific growth rates and feed efficiency ratios did not differ significantly between worms fed with either diets, nor were there significant differences in the proportion of individuals in the oocyte size classes.La supervivencia, el crecimiento, la utilización del alimento y la oogénesis de Nereis diversicolor (O. F. Müller, 1776) alimentado con pienso de dorada Sparus auratus L., 1758 fueron estudiados durante 65 días. Los poliquetos se cultivaron en tres tanques replicados con 50 individuos en cada uno (255 indiv · m_2). Como control se utilizó Tetramin®, una dieta común para peces ornamentales y en experimentos de laboratorio con poliquetos. La supervivencia fue alta (95,3 %) en ambos tratamientos y no se vio afectada significativamente por la dieta. El aumento de peso y los cocientes de eficiencia alimentaria no variaron significativamente entre los poliquetos alimentados con ambas dietas. Entre los grupos experimentales no hubo diferencia significativa en la proporción de individuos por clases de tamaño de los oocitos.Instituto Español de Oceanografí