Percorrer por data de Publicação, começado por "2022-10-21"
A mostrar 1 - 10 de 25
Resultados por página
Opções de ordenação
- Evaluation of valproic acid toxicity in duckweed, Lemna minorPublication . Machado, Beatriz; Prudêncio, Cristina; Ferraz, Ricardo; Barros, PiedadeIn the last years the contamination of water caused by drugs has increased significantly. The main cause is the increase of the number and quantities of drugs that is being used. Many of these compounds cannot be removed effectively by wastewater treatment plants. This problem affects the water cycle and, consequently, all the environment as well as the human health, so it is important to find new methods that can help the removal of drugs from the water. This research is aimed to understand the influence of different concentrations of valproic acid on the growth of the duckweed Lemna minor. After 7 days of exposure it was analysed the number of fronds, the length of the root and the chlorophylls content. The chlorophylls of the Lemna minor samples were analysed by spectrophotometry. The number of fronds was influenced by the concentration of valproic acid. The higher concentrations (0,1 mg/mL; 0,05 mg/mL; 0,025 mg/mL) showed an inhibitory effect while the lower concentrations (0,005 mg/mL; 0,0001 mg/mL) showed a stimulating effect. Relative to the control, the number of fronds was lower in the higher concentrations and higher in the lower concentrations. The root length was affected in all the concentrations. Comparative to the control the higher concentrations presented a diminution of the root’s length while the higher ones had an increase. Like the other parameters the concentration of chlorophylls was affected in all the samples. In the higher concentrations (0,1 mg/mL; 0,05 mg/mL; 0,025 mg/mL) the quantity was lower, comparatively to the control, and in the lower ones (0,01 mg/mL; 0,005 mg/mL; 0,0001 mg/mL) it was higher. In general, the valproic acid influenced all the parameters evaluated: number of fronds, length of the root and concentration of chlorophylls. In the higher concentrations it is notable an inhibitory effect while the lower concentrations have a stimulating one.
- Sustainable valorization of phenolic compounds from Castanea sativa shells for pharmaceutical VPublication . Ferreira, Ana Sofia; Silva, Ana Margarida; Pinto, Diana; Moreira, Manuela M.; Ferraz, Ricardo; Švarc-Gajic, Jaroslava; Costa, Paulo; Delerue-Matos, Cristina; Rodrigues, FranciscaChestnut (Castanea sativa) fruits have an enormous global ecological and economic impact, despite the large generation of by-products during its industrialization process, namely shells, 1 . On the last years, the valorisation of chestnut shells for nutraceutical purposes arises as a challenge due to its richness in bioactive compounds, particularly phenolics. Subcritical Water Extraction (SWE) is an eco-friendly promising method to extract bioactive compounds using water as solvent, with fast processing time and high yield2 . Therefore, the aim of this work was to produce a bioactive extract with antioxidant, antiradical scavenging power and antimicrobial activity, as well as low cytotoxic effect on buccal epithelial cell lines (HSC3 and TR146), by optimizing the extraction temperature (110 °C – 180 °C) of C. sativa shells through SWE. The optimal temperature of extraction was 110 ºC, revealing the highest phenolic and flavonoid contents (239.53 mg of gallic acid equivalents (GAE)/g dry weight (dw) and IC50=148.68 µg/ml, respectively) as well as the highest antioxidant activity (4240.38 µmol of ferrous sulphate (FeS)/g). Additionally, the 110°C extract showed the higher antiradical activity (IC50=426.88 g/ml for DPPH assay) and a good capacity to scavenge reactive oxygen species, namely HOCl and ROO• (IC50=4.47 g/ml and 0.73 mol of Trolox equivalents/mg dw, respectively). Also, high concentrations of phenolic acids, such as gallic and protocatechuic acids and flavonoids (catechin, epicatechin and rutin), composed the phenolic profile. All extracts obtained demonstrated antimicrobial activity against different microorganisms present in the oral cavity during oral mucositis state, such as Porphyromonas gingivalis, Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis and Escherichia coli. The MTT assay revealed that the lowest IC50 was achieved for the 110°C extract in the HSC3 and TR146 cell lines (IC50=1325.03 and 468.15 µg/ml, respectively). This work demonstrated the potentialities of SWE to valorize C. sativa shells as a valuable source of compounds that may be suited for the potential application for oral mucositis treatment.
- Actinobacteria as new probiotics for preventing fish diseases in aquaculturePublication . Santos, Matilde; Girão, Mariana; Oliveira, Rui S.; Carvalho, FátimaIn order to meet the food needs of a constantly growing world population, aquaculture emerges as the fastest growing food production sector. However, disease outbreaks due to opportunistic bacterial pathogens cause large losses. Antibacterial chemicals used indiscriminately have resulted in resistant bacteria and antibiotic resistance genes. Ecological solutions such as probiotics are needed. Probiotics are microorganisms introduced into another organism that can have beneficial effects on the host as well as improve the external environment. Actinobacteria are an important biotechnological resource, as they produce a great diversity of secondary metabolites with a high range of bioactivities, including antimicrobial. The aim of this study was to explore the probiotic potential of some marine actinobacteria to prevent aquaculture fish diseases. For this, a screening of antimicrobial activity was performed using agar-based disk diffusion and Minimum Inhibitory Concentration (MIC) assays, against three Gram-negative bacterial fish pathogens: Aeromonas hydrophila, Edwardsiella tarda and Pseudomonas anguilliseptica. A total of 54 out of 103 actinobacterial extracts tested, presented bioactivity against these microorganisms, so that the growth of all three Gram-negative pathogens used was inhibited. The diameter of the inhibition halos varied between 8 and 20 mm. Tested extracts presented MIC values of 1000 µg/ml, except for Isoptericola chiayiensis (500 µg/ml). Microbispora bryophytorum, Isoptericola chiayiensis and Nocardia nova were some of the bacteria with the most promising results. Overall, actinobacteria associated with seaweed proved to be a potential source of probiotics to inhibit pathogens in aquaculture fish.
- Relatório de Estágio Auditoria FinanceiraPublication . Meireles, José Miguel Gomes; Dias, Alcina Augusta de Sena PortugalCurrently, our society is experiencing instability since we have been ravaged by the Covid-19 pandemic. This paradigm strongly affected the entities business, not only placing them below their outlined objectives, but also jeopardizing, in many cases, their sustainability and even their survival in economic aspects. In addition, there is a prospect of uncertainty due to the military conflict between Russia and Ukraine, as it endangers price level and supply of goods and services worldwide, and it is not possible, at this time, to determine the real impact of this incident regarding financial aspects. Hereupon, it is important especially now that auditors and statutory auditors perform extraordinarily well its functions in order to provide error-free statement financial information to its users. Thus, this narrative addresses a wide range of concepts associated with auditing financial information, auditor’s role and its importance in the process, as well as the code of conduct by wich it must be bound, as well as a set of fundamental steps to provide accurate information as intended. After reviewing the literature, the methodology is followed where the problem is developed, build the assertions for the research questions raised and finally its explained the analysis model.
- Honey from natural park of Montesinho: insights from DNA extraction methodology for botanical identificationPublication . Soares, Sónia; Magalhães, Leandro; Barbosa, Rui; Delerue-Matos, CristinaHoney is a sweet natural substance produced by bees from the nectar of plants and/or secretions of living parts of plants. It consists essentially of simple sugars (68%) and water (18%) and smaller quantities of other components such as vitamins, minerals, proteins, organic acids, phenolic compounds, among others. Those are highly dependent of the botanical species visited by bees, conferring to each honey different and distinct organoleptic and biological properties. The botanical differences give rise to two types of honeys, monofloral, consisting essentially of the nectar of a single plant species, and multifloral, arising from several plant species. This strict relation of botanical origin and its biological and organoleptic properties lead to a quality distinction of honey types. There are honeys with high market values due to its particular flavour, taste and specific biological properties, such as monofloral honey and honeys with the denomination of Protected Designation of Origin, such as honey produced in Natural Park of Montesinho. With this, honey is produced and marketed based on its colour, flavour, density and biological properties, being extremely important to assess its quality and authenticity. DNA-based methods are simple, fast and precise promising tools for species identification. However, honey is a complex matrix with high amounts of sugars and other compounds that inhibit the PCR reaction. Thus, it is important to find the best DNA extraction method to achieve good yields and purities. In this work, different pre-treatments were performed and results were compared. For the DNA extraction, a commercial DNA extraction kit was used. The quality of DNA extracts was assessed by spectrophotometry and electrophoresis. Results revealed that the use of ultrasounds in honey pre-treatments achieved the best yields and purity. Additionally, a PCR amplification targeting the gene 18S rRNA was performed to evaluate amplifiability of the extracted DNA. As expected, all extract samples revealed to have amplifiable DNA. Combining a simple and easy honey pre-treatment with an effective DNA extraction method, allows us to get desired good extracts. Thus, this methodology is the first step for further studies involving botanical identification of honey and honey quality studies.
- Evaluation of the probiotic potential of a strain of Saccharomyces cerevisiaePublication . Areal-Hermida, Lara; Pichardo-Gallardo, Ángeles; Coelho, Pedro; Prudêncio, Cristina; Sieiro, CarmenAccording to the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO), probiotics are living microorganisms that, when administered in appropriate quantities, can confer a beneficial effect on the health of the host. Probiotic potential has been demonstrated especially for many strains of different species of bacteria. However, there are fewer strains of yeast for which their probiotic properties have been studied, despite their advantages, which include the fact that they are not affected by antibacterial antibiotics or their inability to disperse antibiotic resistance genes. As a result, there is a growing interest in characterizing new yeasts as probiotics. The aim of this study was to evaluate in our laboratories the probiotic potential of a strain of Saccharomyces cerevisiae var. boulardii (the main species marketed as a probiotic so far), to compare it with that of other yeasts. Strain identification was carried out by analyzing the ITS and D1/D2 regions of the rDNA. Regarding the ability of the strain to survive at 37ºC and resist gastrointestinal conditions, the strain showed 100 % viability at 37ºC and between 95-100 % in synthetic gastric and duodenal juices (pH 2-7.5, 0.3-10 % bile salts, 0.3 % pepsin and 0.1 % pancreatin). In addition, the selfaggregation and hydrophobicity properties shown by the strain allowed inferring the ability to adhere to the intestine, which was confirmed in Caco-2 cells. Additionally, the strain presented other properties of interest for probiotics, including a high anti-oxidant capacity and pathogen coaggregation, as well as a variable cytotoxic activity against different tumor cell lines.
- Resistance of actinobacteria and rhizobia from wild Saharan plants to environmental stresses and their phosphate solubilization capacityPublication . Pereira, Adriana; Girão, Mariana; Fecih, Thinhinane; Carvalho, Fátima; Oliveira, Rui S.Plant growth promoting bacteria (PGPB) enhance plant development through various mechanisms such as the fixation of atmospheric nitrogen, production of siderophores and phosphate solubilization. This could be beneficial for the implementation of more sustainable agricultural practices. The objective of this study was to evaluate the effect of temperature and salinity variation as well as to evaluate the phosphate solubilization capacity of a collection of bacteria, originating from various sites in the Algerian Sahara Desert]. These sites are affected by abiotic stresses such as wide variations in temperature range and high salinity levels, so PGPB for inoculation in these soils need to be adaptable and withstand extreme conditions. To carry out this study, the bacteria were subjected to different temperatures and concentrations of NaCl. The phosphate solubilization capacity was evaluated, in the National Botanical Research Institute’s Phosphate Growth (NBRIP) medium. Overall, the tested bacteria did not solubilize phosphate, since no halos were observed around the bacterial colonies. The bacteria most tolerant to a wider range of temperatures and salinities and, therefore, most promising for inoculation in semi-arid and arid soils were Afipia sp. 61 and Afipia massiliensis 21, which showed significant growth in all studied conditions. In general, it was observed that most bacteria grow at temperatures and salinities, different from their common growth range.
- O Controlo Interno e a Gestão de Risco - Estudo CasoPublication . Almeida, Herlander Pereira Neto de; Dias, Alcina Augusta de Sena PortugalFrom their beginning to the current day, organizations have encountered certain obstacles that hinder their modus operandi. The concern of entities to identify and solve, in a welltimed manner, these obstacles gave rise to the creation of risk management analysis models to better analyze and treat the risks underlying their activity. At the same time, internal control emerged as a fundamental part of risk management, as it is a process devised by management, administration or other officers of a particular institution, designed to provide reasonable certainty about the achievement of defined objectives. Internal auditing also plays an important role in the effectiveness of internal control within an organization, as it is designed to assist management in the process of implementing internal control, as well as in monitoring and verifying the proper functioning of the controls in place. This paper was prepared with the objective of assessing, based on a detailed literature review and subsequent empirical study, the degree of importance of implementing internal control and risk management within an entity. The study focused on two national companies, from completely different sectors and sizes, where opinion was collected based on interviews in order to be able to validate the study hypotheses.
- The Use Of Musical Cultural Heritage In The Eurovision Song Contest As A Commodity For National GainsPublication . Silva, Augusto André Mourão da; Cerqueira, Carina Raquel OliveiraAs means to not only safeguard Cultural Heritage, but also the possibility to create a profitable and providing industry out of such assets, in this dissertation it is proposed the conceptualization of two hypothesis, being: the commodification of cultural heritage, mainly musical or through music, as well as the participation with said music in the Eurovision Song Contest as a path to exposure, awareness and to consequentially attain economic gains, both local and national. In this dissertation , such topics are presented as follows: a general contextualization of the Eurovision Song Contest, the contextualization and theorization of Commodification in Economy and Culture, as well as the use of the Eurovision Song Contest to promote Culture and the potential consequences, claims supported by public enquire.
- CytoPath®Easy: screening of cervical cancerPublication . Fernandes, Sílvia; Vilarinho, Ana Sofia; Silva, ReginaRecently, CytoPath®Easy kit was created by DiaPath S.p.A. and started to be commercially available for the screening of cervical cancer. Using this methodology, epithelial cells are immersed in a preservative liquid, and a thin-layer of cells in the slide is obtained through gravity sedimentation and filtration. The main objectives of this study are to evaluate the efficacy for the processing of cervical samples, for the detection of pre-neoplastic lesions and for the nucleic preservation and extraction by the kit. For this purpose, 215 cervical samples obtained by self-sampling were used: 174 were collected and processed by CytoPath® Easy and, as a control, 41 were collected and processed by the Thinprep® method. The samples were processed, stained by the Papanicolaou method, and independently evaluated microscopically for various morphological parameters; nucleic acids were isolated and evaluated for purity and integrity by spectrophotometry. Results obtained showed that both methods have a good performance, allowing the morphological evaluation of the cervical epithelium. However, the statistical analysis reveals that the methods are different from each other, with overall lower results being obtained in the method under study (p<0.001). In turn, both methods allow the extraction of good quality and quantity of DNA. Although some differences were found regarding morphology of the cells fixed and processed by the CytoPath®Easy method, this new methodology reveals efficient for the preservation of nucleic acids. Thus, its use in cervical cancer screening is recommended.
- «
- 1 (current)
- 2
- 3
- »