Bactéria açoriana ativa contra mosquitos vetores de infeções

A secção Biologia é coordenada pelo Professor Universitário Armindo Rodrigues.As infeções emergentes ou reemergentes são infeções causadas pela entrada de um agente infeccioso num local considerado indemne até então ou pelo reaparecimento desse agente depois de um longo período de ausência. A globalização, ao aumentar significativamente o movimento de pessoas e o intercâmbio de materiais entre continentes, associada às alterações climáticas, tem contribuído para a disseminação de agentes infeciosos, originando-se assim o aparecimento de novas infeções ou o seu reaparecimento em locais onde terão existido antes. Muitos destes agentes infecciosos têm como hospedeiros intermediários artrópodes que funcionam como vetores para a sua transmissão e também disseminação. Exemplos de vetores são os mosquitos que transmitem um grande número de agentes infecciosos humanos e animais, alguns deles altamente patogénicos, como o protozoário causador da malária, a infeção mais letal no mundo, e muitos vírus, entre eles o causador da Dengue. […].info:eu-repo/semantics/publishedVersio

Efeito do consumo do chá branco no coração de ratos diabéticos tipo 2

According to the World Health Organization (WHO), diabetes mellitus (DM) is the ninth leading cause of death worldwide, and 80% of those deaths are due to cardiovascular disease. The heart functions as a pump with a continuous need for energy and therefore is very susceptible to metabolic and/or oxidative alterations. It is well known that DM induces important metabolic alterations that result in increased oxidative stress (OS). Many medicinal plants are used worldwide to counteract the deleterious effects of DM. Although it is a fact that some harmful characteristics of DM are indeed ameliorated, the mechanisms by which medicinal plants improve the body response to this disease remain unknown. In the last few years, scientific studies concerning the effect of tea consumption, one of the most consumed beverages in the world, significantly increased. There are several works reporting that tea consumption may improve heart function in diabetic individuals. However, much of these studies are focused in green tea (GT) and most of the mechanisms of tea action remain unknown. Herein, we hypothesized that the consumption of the less studied tea, the white tea (WTEA), improves the heart functioning of diabetic individuals. To test our hypothesis, we used a STZ-induced Type 2 diabetes (T2D) rat model. The animals were divided in 3 groups: control, STZ-induced T2D (STZ) and WTEA drinking STZ-induced T2D rats (STZ+WTEA). Before sacrifice, the animals were subjected to a glucose tolerance and insulin sensitivity tests. Heart lipid peroxidation and protein oxidation were determined. Glucose, lactate, alanine and acetate contents in the hearts were quantified. mRNA expression levels of glucose transporter-1 (GLUT1), lactate dehydrogenase (LDH) and monocarboxylate transporter 4 (MCT4) were also determined, as well as LDH activity, in the heart. Our results show that WTEA consumption restored insulin sensitivity and glucose tolerance in STZ-induced T2D rats. Besides, WTEA consumption restored lipid peroxidation to control values and decreased protein oxidation in hearts from STZ-induced T2D rats. Finally, STZ-induced T2D rats presented an impaired glycolysis that appears to be ameliorated by WTEA consumption. In these processes, regulation of GLUT1 and LDH activity proved to be essential in the protective effect shown by WTEA consumption. More studies are needed to confirm the beneficial effects of WTEA consumption but our results provide clear evidence that WTEA ingestion can be a good, safe and inexpensive strategy to decrease the deleterious effects of T2D to the heart.De acordo com a Organização Mundial de Saúde (WHO), a diabetes mellitus (DM) é a nona causa de morte a nível mundial e cerca de 80% destas mortes são devido a doenças cardiovasculares. O coração funciona como uma bomba e tem uma necessidade contínua de energia, sendo muito susceptível a alterações metabólicas e/ou oxidativas. É bem conhecido que a DM é responsável por alterações metabólicas importantes que resultam num aumento de stress oxidativo (OS). Muitas plantas medicinais são usadas por todo o mundo para contrariar os efeitos deletérios da DM. De facto, alguns efeitos prejudiciais da DM são prevenidos pelo uso dessas plantas, mas os mecanismos pelos quais essa prevenção ocorre, permanecem desconhecidos. Nos últimos anos tem-se assistido a um aumento significativo de estudos científicos baseados no consumo de chá, uma das bebidas mais consumidas no mundo. Existem vários estudos que demonstram que o consumo de chá pode melhorar a função cardíaca de indivíduos diabéticos. No entanto, a maioria destes estudos está focada no chá verde (GT) e os mecanismos de acção do chá permanecem desconhecidos. Neste trabalho colocámos a hipótese de que o consumo de chá branco (WTEA), que é o chá menos estudado, poderia melhorar o funcionamento do coração de ratos diabéticos. Para testar a nossa hipótese usámos um modelo de rato para a diabetes tipo 2 (T2D). Os animais foram divididos em 3 grupos: grupo controlo, grupo T2D induzido por estreptozotocina (STZ) e grupo T2D induzido por STZ ao qual foi administrado chá branco (STZ+WTEA). Antes do sacrifício, os animais foram sujeitos aos testes de tolerância à glucose e resistência à insulina. Após recolha do tecido cardíaco, os níveis de peroxidação lipídica e de oxidação proteica foram determinados. O conteúdo de glicose, lactato, alanina e acetato nos corações foi quantificado. Os níveis de mRNA do transportador de glicose 1 (GLUT1), lactato desidrogenase (LDH) e transportador de monocarboxilatos 4 (MCT4) foram igualmente determinados, assim como a actividade da LDH. Os resultados obtidos demonstram que o consumo regular de WTEA permitiu a recuperação da sensitividade à insulina e da tolerância à glicose nos ratos T2D. Além disso, preveniu a peroxidação lipídica e diminuiu a oxidação proteica nos corações de ratos T2D. Esses ratos apresentaram distúrbios severos no processo glicolítico que foram normalizados pelo consumo de WTEA. Para isso contribuiu um efeito importante na regulação da expressão do GLUT1 e na actividade da LDH. Mais estudos são necessários para confirmar os efeitos benéficos do consumo regular de WTEA mas os nossos resultados demonstram que a ingestão de chá branco pode ser uma boa estratégia para diminuir os efeitos nefastos da T2D na função cardíaca

Early (17th and 18th centuries) drawings of lantern-flies and mentions of their bioluminescence (Fulgora spp., Hemiptera, Homoptera, Fulgoridae)

For many years it was believed that the first two notices about New World lantern-flies (Fulgoridae), with descriptions and illustrations of the insects, as well as mentions of their luminescence, were due to Nehemiah Grey (1681) and Maria Sibylla Merian (1705). However, there are illustrations of lantern-flies prior to Grew’s paper, and the first of them, by Jacques de Heyn (1620), also refers to the bioluminescence of those insects. The second is a watercolour by Pieter Holstejn (1614-1673), a Dutch Golden Age painter and engraver. Several illustrations of lantern-flies were lately produced during the 17th and 18th centuries, for example by Alexander Marshal (ca. 1620-1682), an English entomologist, gardener and botanical artist, by Iob Leutholf (1694), and also by an anonymous artist (first half of the 18th century).For many years, it was believed that the first two notices about New World lantern-flies (Fulgoridae), with descriptions and illustrations of the insects, as well as mentions of their luminescence, were due to Nehemiah Grey (1681) and Maria Sibylla Merian (1705). However, there are illustrations of lantern-flies prior to Grew’s paper, and the first of them, by Jacques de Heyn (1620), also refers to the bioluminescence of those insects. The second is a watercolour by Pieter Holstejn (1614‑1673), a Dutch Golden Age painter and engraver. Several illustrations of lantern-flies were lately produced during the 17th and 18th centuries, for example by Alexander Marshal (ca. 1620‑1682), an English entomologist, gardener, and botanical artist, by Iob Leutholf (1694), and also by an anonymous artist (first half of the 18th century)

Recolha de amostras de solo na ilha de Santa Maria para isolamento de bactérias entomapatogénicas

XIV Expedição Científica do Departamento de Biologia - Santa Maria 2009.Durante a XIV Expedição Científica do Departamento de Biologia à Ilha de Santa Maria em 2009 recolheram-se 50 amostras de solo e água a diferentes altitudes e com diversos cobertos vegetais, as quais foram transportadas para o laboratório de Entomopatologia para isolamento de bactérias entomopatogénicas. Destas 50 amostras obtivemos 250 isolados puros. Estes isolados aguardam identificação a nível do Grupo Bacillus cereus, onde se enquadra o Bacillus thuringiensis. Serão usados métodos bioquímicos e moleculares. Todos os isolados estão depositados no Banco de Bactérias de Bacillus dos Açores | Centro de Investigação do Recursos Naturais (CIRN)

Novas metodologias para a fermentação alcoólica do soro de queijo

Em Portugal, são diariamente lançados no meio ambiente cerca de 1 milhão de litros de soro de queijo – fracção líquida resultante do fabrico de queijo. O impacte ambiental ocasionado por tal volume de efluentes, com elevada carga orgânica, é enorme. Recorrendo à tecnologia de DNA recombinante, modificou-se uma estirpe floculante de Saccharomyces cerevisiae sendo-lhe conferida capacidade para fermentar lactose. Com esta estirpe foram realizados ensaios de fermentação em contínuo, utilizando como substrato soro de queijo desproteinizado, possibilitando operar a uma taxa de diluição máxima de 0,45 hˉ¹, correspondente a uma produtividade volumétrica em etanol de cerca de 10 gLˉ¹hˉ¹, cerca de 7 vezes superior aos processos actualmente existentes. O processo integrado de recuperação da proteína e fermentação alcoólica permite uma redução superior a 90 % de CQO do soro, o que, por si só, se traduz numa enorme diminuição do impacte ambiental negativo, e, por outro lado, abre a porta à produção de etanol com viabilidade económica.Instituto de Biotecnologia e Química Fina (IBQF); PROLAC; Agência de Inovação; Fundação para a Ciência e Tecnologia (FCT)

Enhancement of metabolic rates of yeast flocculent cells through the use of polymeric additives

The influence of several polymeric additives on specific glucose uptake rate of flocs of a S. cerevisiae strain - S. cerevisiae NRRL Y 265 was studied. A special continuous membrane microreactor was used to measure glucose uptake on the presence of calcium and of the tested additives - two cationic polymers - bis(polyoxyethylene- bis(amine)) 20,000 and BPA 1,000 and one anionic polymer -- Magna Floc LT25. An increase on glucose uptake rate was always observed when comparing with calcium bound flocs. For bis(polyoxyethylenebis( amine)) 20,000 the increase was only 19% but for BPA 1,000 a value of more than 50% was observed. For Magna Floc LT25 a two fold increase was measured. The determination of floc size and porosity in the presence of the additives indicated that, on the basis of these parameters, it was not possible to explain the observed glucose uptake rates. The floc porosites in additive bound flocs were similar and 10% larger than for calcium bound flocs and glucose uptake rate was larger for the largest flocs - Magna Floc LT25 bound flocs were the largest followed by BPA t,000, bis(polyoxyethylene-bis(amine)) 20,000 and calcium bound flocs. These values disagree with what should be expected in diffusion controlled processes. The calculation of intercellular floc distance indicated that polymeric additives act on the reduction of diffusional limitations by increasing the available flux area for glucose inside the flocs. By analysing different kinds of packings, it was also observed that the packing arrangement for yeast cells in flocs is close to the cubic packing. The simulation of this arrangement for the obtained floc sizes confirmed that the 10% increase in floc porosity is sufficient to explain the increase in the available flux area

Construction of a flocculent saccharomyces cerevisiae fermenting lactose

A flocculent Saccharomyces cerevisiae strain with the ability to express both the LAC4 (coding for b-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus was constructed. This recombinant strain is not only able to grow on lactose, but it can also ferment this substrate. To our knowledge this is the first time that a recombinant S. cervisiae has been found to ferment lactose in a way comparable to that of the existing lactose-fermenting yeast strains. Moreover, the flocculating capacity of the strain used in this work gives the process several advantages. On the one hand, it allows for operation in a continuous mode at high cell concentration, thus increasing the system's overall productivity; on the other hand, the biomass concentration in the effluent is reduced, thus decreasing product separation/purification costs.Instituto de Biotecnologia e Química Fina (IBQF).Fundação para a Ciência e a Tecnologia (FCT) - PRAXIS XXI/BD/11306/97

Aspergillus niger β-galactosidase production by yeast in a continuous high cell density reactor

The continuous production of extracellular heterologous beta-galactosidase by a recombinant flocculating Saccharomyces cerevisiae, expressing the lacA gene (coding for beta-galactosidase) of Aspergillus niger was investigated. A continuous operation was run in a 6.51 airlift bioreactor with a concentric draft tube using lactose as substrate. Data on the operation with semi-synthetic medium with 50 and 100 g/l initial lactose concentrations are presented. The best result for beta-galactosidase productivity-6.2 x 10(5) U/l h-was obtained for a system operating at 0.24 h(-1) dilution rate and for a lactose concentration in the feed of 50 g/l. This value represents a 11-fold increase in beta-galactosidase productivity when compared to batch culture. Together with extracellular beta-galactosidase production an ethanol productivity of 9 g/l h was obtained for the bioreactor fed with 50 g/l initial lactose concentration at 0.45 h(-1) dilution rate. In addition to beta-galactosidase and ethanol production, this system allowed for complete lactose metabolism. The feasibility and advantages of using continuous high-cell-density systems operating with flocculent yeast cells for extracellular protein production is clearly shown