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- Bee propolis effect on protection of RBCs membrane integrityPublication . Moreira, Leandro; Rogão, Mónica; Pereira, Ana Paula; Morais, Margarida; Costa, Bruno; Dias, L.G.; Dias, Teresa; Estevinho, Leticia M.Propolis is a resinous substance collected from plants by bees. The propolis composition depends on the surrounding vegetation, the season, and the area from which derive. This hive product usually contains a variety of chemical compounds such as polyphenols (flavonoids, phenolic acids and esters), steroids, and amino acids. The hereditary spherocytosis (HS) is a congenital hemolytic anemia, with origin in the modification of membrane proteins of erythrocytes, which leads to increased susceptibility to hemolysis and a decrease of the cell over-life.
- The effects of starter culture on the biogenic amine accumulation in traditional Portuguese dry sausagesPublication . Panov, Dimitriy; Dias, L.G.; Pereira, Ana Paula; Lopes-da-Silva, M.F.; Peres, António M.; Estevinho, Leticia M.; Dias, TeresaLinguiça is a highly popular and appreciated traditional Portuguese dry fermented sausage. Its production involves a ripening step, which provides favorable conditions for biogenic amines formation due to microbial growth, acidification and proteolysis. The levels of biogenic amines in dry-fermented sausages are highly dependent on the type of product, producer and could even vary from batch to batch. The microbiological quality of raw materials, technological process and growth/type of microbial flora are some factors that may explain this variability. To the authors’ best knowledge, only few studies focused on the quantification of biogenic amines in Portuguese traditional sausages, reporting variable levels of accumulation, being the tyramine the most abundant followed by putrescine and cadaverine. Starter cultures have been used aiming to prevent or reduce the formation of biogenic amines during the manufacture of dry-fermented sausages. Based on the results reported in the literature, the use of starter cultures may reduce or not the biogenic amines accumulation during the fermentation of sausages. In this work, it was evaluated the influence of one commercial starter culture (Texel®ELCE Br, Danisco) on biogenic amine accumulation during manufacture process and storage. Parameters such as pH value, water activity and microbial counts were also assessed. In general the results pointed out that the starter culture inhibited the accumulation of biogenic amines (putrescine, cadaverine and tyramine) as well as the growth of S. aureus and Enterobacterias. This inhibitory effect was clear during ripening and storage periods. On the other hand the starter culture did not have a significant effect on spermidine and spermine concentrations.
- The Role of Honey and Propolis in the Treatment of Infected WoundsPublication . Pascoal, Ananias; Feás, Xesús; Dias, Teresa; Dias, L.G.; Estevinho, Leticia M.Honey is defined as the natural substance produced by Apis mellifera bees from plant nectar, from secretions of the living parts of plants, or from the excretions of plant sucking insects feeding on the living parts of plants.1,2 Honeybees collect, transform, and combine this with specific substances of their own, and then store it and leave it in the honeycomb to ripen and mature. This natural product is generally composed of a complex mixture of carbohydrates and other less common substances, such as organic acids, amino acids, proteins, minerals, vitamins, lipids, aroma compounds, flavonoids, pigments, waxes, pollen grains, several enzymes and other phytochemicals.3 5 However, the specific composition depends on many factors, such as the nectar composition of the source plant, the species of bee, the climate, environmental and seasonal conditions, agricultural practices and treatment of honey during extraction and storage.6-9 As a natural, unprocessed and easily digested food, honey plays an important role in the human diet, and is also used in pharmaceutical and cosmetic industries.10 Modern science has studied the medical significance of honeys in healing wounds and burns,11 oncology care,12 as well as its antioxidant and antimicrobial properties.
- Red blood cells disease (hereditary spherocytosis): propolis effectPublication . Moreira, Leandro; Pereira, Ana Paula; Bento, Margarida; Costa, Bruno; Dias, L.G.; Dias, Teresa; Estevinho, Leticia M.Propolis is a resinous substance collected from plants by bees, used since the Egyptian civilization. The hereditary spherocytosis(HS) is a type of transmission of hereditary anemia.Clinically, individuals usually present from a symptomatic conditions to severe haemolytic anaemia. The objective of this study was to evaluate the effect of two propolis extracts, in the osmotic fragility of patient red blood cell (RBC) membrane with HS. It was found that propolis decreased the erythrocytes membrane fragility, beingth effect of Bornes propolis more pronounced. The obtained results suggest that in vitro, the membrane fragility may be increased under oxidative stress conditions inpatient RBC’s, and the protection effect of propolis is due to its antioxidant properties. These results open doors for future investigations in order to elucidate the mechanisms, and identify the most relevant compounds involved in the fragility of the erythrocyte membrane.
- Bee propolis effect on protection of RBC’s membrane integrityPublication . Moreira, Leandro; Rogão, Mónica; Pereira, Ana Paula; Morais, Margarida; Costa, Bruno; Dias, L.G.; Dias, Teresa; Estevinho, Leticia M.Propolis is a resinous substance collected from plants by bees. The propolis composition depends on the surrounding vegetation, the season, and the area from which derive. This hive product usually contains a variety of chemical compounds such as polyphenols (flavonoids, phenolic acids and esters), steroids, and amino acids. The hereditary spherocytosis (HS) is a congenital hemolytic anemia, with origin in the modification of membrane proteins of erythrocytes, which leads to increased susceptibility to hemolysis and a decrease of the cell over-life. The HS is the most common red blood cell (RBC) membrane disorder in European Caucasians, with a prevalence of roughly 200-300 per 106, and to Japanese population 5.7-20.3 per 106. The aim of the present work was to determine if propolis extracts could affected the red cell membrane integrity and comparing the effect of two propolis extracts from different regions (Bornes - Trás-os-Montes; Fundão - Beira Interior). In this work, two adults were studied, one with the syndrome HS splenectomized and one healthy used as control. Diagnosis of HS was made by clinical features, identification of spherocytes on peripheral blood smears and abnormal osmotic fragility. The results show that the two propolis extracts affected the erythrocyte membrane fragility in both individuals (control and patient with HS).
- Eficácia da própolis no controlo da loque americana. Avaliação em zonas controladasPublication . Vilas-Boas, Miguel; Veloso, Ana C.A.; Peres, António M.; Dias, L.G.; Dias, Teresa; Cardoso, Susana M.; Kluskens, Leon; Rocha, Isabel
- Dietary sugars analysis: quantification of fructooligossacharides during fermentation by HPLC-RI methodPublication . Correia, Daniela M.; Dias, L.G.; Veloso, Ana C.A.; Dias, Teresa; Rocha, Isabel; Rodrigues, Lígia R.; Peres, António M.In this work, a simple chromatographic method is proposed and in-house validated for the quantification of total and individual fructooligossacharides (e.g., 1-kestose, nystose, and 1F-fructofuranosylnystose). It was shown that a high-performance liquid chromatography with refractive index detector could be used to monitor the dynamic of fructooligossacharides production via sucrose fermentation using Aspergillus aculeatus. This analytical technique may be easily implemented at laboratorial or industrial scale for fructooligossacharides mass-production monitoring allowing also controlling the main substrate (sucrose) and the secondary by-products (glucose and fructose). The proposed chromatographic method had a satisfactory intra- and inter-day variability (in general, with a relative standard deviation lower than 5%), high sensitivity for each sugar (usually, with a relative error lower than 5%), and low detection (lower than 0.06+/-0.04 g/L) and quantification (lower than 0.2+/-0.1 g/L) limits. The correct quantification of fructooligossacharides in fermentative media may allow a more precise nutritional formulation of new functional foods, since it is reported that different fructooligossacharides exhibit different biological activities and effects.
- Propolis influence on erythrocyte membrane disorder (hereditary spherocytosis): a first approachPublication . Moreira, Leandro; Dias, Teresa; Dias, L.G.; Silva, José Paulo; Estevinho, Leticia M.Propolis is a resinous substance collected from plants by bees. Its composition d epends on the vegetation, the season, and the source area. It usually contains many chemical compounds such as polyphenols, steroids and amino acids. The hereditary spherocytosis (HS) is a type of anaemia characterized by microcytic and hyperchromic red cells, spherical in shape and without central pallor. Clinically, subjects present from asymptomatic conditions to severe haemolytic anaemia.
- Discrimination of three bacteria species using a potentiometric electronic tonguePublication . Teixeira, Guilherme Gobbi; Katel, Anna; Veloso, Ana C.A.; Dias, L.G.; Dias, Teresa; Peres, António M.The detection, monitoring and/or prevention of microorganism growing is of utmost relevance in several research fields, from food to environmental areas, being an important topic either from an academic or an industrial point of view. Conventional methods like plating techniques are the most widely used, being needed novel and faster screening methodologies like electronic noses, electronic tongue (E-tongue) and impedance based methods. In the present work, a potentiometric E-tongue (Fig.1), comprising 40 lipid polymeric sensor membranes with cross-sensitivity, was used to identify and discriminate three bacteria (Enterococcus faecalis ATCC29212; Staphylococcus aureus ATCC653 and Escherichia coli ATCC29998) at two concentrations levels (low and high). Brain Heart Infusion Broth medium was used for cultivating each of the three microorganisms, which were then individually inoculated into 1L Erlenmeyer flask (working volume of 300 mL) and incubated overnight (batch mode) at 35ºC, on a rotary shaker (90 rpm). After incubation, the biomass was spectrophotometrically determined, being measured the optical density at 550 nm. The cultures were split in volumes of 50 mL. The cells of each sample were harvested (centrifugation at 9000 rpm for 10 min) and stored at -20ºC. The obtained biomass was dried at 30ºC, and stored at -20ºC. Before E-tongue analysis, the cells were rehydrated with 20 mL of deionized water for 30 minutes at room temperature and aqueous sample solutions with different cell concentrations were obtained. Each E-tongue analysis took five minutes, enabling establishing a pseudo-equilibrium between the samples and the sensors´membranes, being the signals potentiometric profiles recorded. The classification performance of E-tongue was assessed by applying a linear discriminant analysis (LDA) coupled with the meta-heuristic simulated annealing (SA) variable selection algorithm. The preliminary results showed that E-tongue-LDA-SA predicting model could be established, based on the information gathered by a sub-set of 15 sensors, allowing to correctly classify (100%) (Fig.2) and 85% (original and leave-one-out cross-validation procedure, respectively) of the samples according to the microorganism and respectively concentration level.
- Discrimination of three bacteria species using a potentiometric electronic tonguePublication . Teixeira, Guilherme Gobbi; Katel, Anna; Veloso, Ana C.A.; Dias, L.G.; Dias, Teresa; Peres, António M.The microorganisms were inoculated into the broth medium and grown 90 rpm and 37º overnight in a rotatory incubator