Hermano árbol : (pro reforestación patria) : poesías por y para las fiestas del árbol

Copia digital : Junta de Castilla y León. Consejería de Cultura y Turismo, 201

Efecto de los irrigantes sobre la resistencia a la fractura de premolares

La endodoncia regenerativa ha sido definida como procedimientos basadosbiológicamente y diseñados para reemplazar estructuras pérdidas, incluyendo dentina y estructurasradiculares, y células del complejo dentino-pulpar con tejidos vivos. Ha sido considerada una alternativapara el tratamiento de dientes permanentes jóvenes con ápices inmaduros y necrosis pulpar. Elprocedimiento clínico se basa en la desinfección y posterior formación de un coágulo de sangre en elconducto radicular. Las soluciones irrigantes como el hipoclorito de sodio (NaOCl) y EDTA se usan nosólo para la desinfección sino también para el acondicionamiento de la dentina, con el fin de liberar factoresde crecimiento de la matriz dentinaria, que guían la diferenciación celular.OBJETIVO: Evaluar el efecto de la irrigación sobre la resistencia a la fractura de premolares tratados conel protocolo para endodoncia regenerativa, con hipoclorito de sodio y con irrigación final con EDTA.MATERIALES Y METODOS: Se seleccionaron 10 pares de premolares humanos extraídos homólogos,alos cuales se tomaron fotografías y radiografías periapicales. Se realizaron las aperturas cameralescorrespondientes, se prepararon los conductos con ensanchador de Peeso para simular un diente inmadurocon ápice abierto y se envolvieron las raíces con teflón para simular el ligamento periodontal.Los 20 dientesse dividieron en 2 grupos de 10 premolares cada uno (n=10), asegurando que en cada grupo hubiera unpremolar homólogo de cada par. Grupo A (control) se irrigó con NaOCl al 2,5% y el grupo B (experimental)se irrigó con NaOCl al 2,5% seguido de EDTA al 17%. Posteriormente, se selló el tercio coronario delconducto y la cavidad de acceso con Biodentine. Las muestras fueron seccionadas transversalmente a 3 mmcoronarios al límite amelo cementario y fueron montadas en una resina de composite para mantener lospremolares verticales en una máquina universal para ensayos mecánicos (Instron Corp,Canton,MA,USA).Se aplicó una carga compresiva con una velocidad de desplazamiento de cabezal de 1 mm/minuto sobre laraíz apoyada sobre un cono de acero que ejerció un efecto cuña y se determinó la fuerza necesaria parafracturar la raíz. Los resultados fueron analizados estadísticamente con prueba T.RESULTADOS: La media de la fuerza (N) necesaria para generar la fractura de las raíces en el grupo dondese usó sólo NaOCl fue de 337,84, mientras que para el grupo donde se usó EDTA e NaOCl fue de 345,54.Al comparar ambos grupos con la prueba de t, las diferencias no resultaron estadísticamentesignificativas(p>0.05).CONCLUSIONES: La irrigación final con EDTA no disminuyó la resistencia a la fractura de premolarescon ápices inmaduros previamente irrigados con hipoclorito de sodio al 2,5%

Proteolytic activity and reduction of gliadin-like fractions by sourdough lactobacilli

Aims:  To characterize the peptide hydrolase system of Lactobacillus plantarum CRL 759 and CRL 778 and evaluate their proteolytic activity in reducing gliadin-like fractions. Methods and Results:  The intracellular peptide hydrolase system of Lact. plantarum CRL 759 and CRL 778 involves amino-, di- (DP), tri- (TP) and endopeptidase activities. These peptidases are metalloenzymes inhibited by EDTA and 1,10-phenanthroline and stimulated by Co2+. DP and TP activities of Lact. plantarum CRL 759 and CRL 778, respectively, were completely inhibited by Cu2+. Lactobacillus plantarum CRL 778 showed the highest proteolytic activity and amino acids release in fermented dough. The synthetic 31–43 α-gliadin fragment was hydrolysed to 36% and 73% by Lact. plantarum CRL 778 and CRL 759 respectively. Conclusions: Lactobacillus plantarum CRL 759 and CRL 778 have an active proteolytic system, which is responsible for the high amino acid release during sourdough fermentation and the hydrolysis of the 31–43 α-gliadin-like fragment. Significance and Impact of the Study:  This work provides new information of use when obtaining sourdough starters for bread making. Moreover, knowledge regarding lactobacilli capable of reducing the level of gliadin-like fractions, a toxic peptide for coeliac patients, has a beneficial health impact

Modelling coral reef futures to inform management: can reducing local-scale stressors conserve reefs under climate change?

Climate change has emerged as a principal threat to coral reefs, and is expected to exacerbate coral reef degradation caused by more localised stressors. Management of local stressors is widely advocated to bolster coral reef resilience, but the extent to which management of local stressors might affect future trajectories of reef state remains unclear. This is in part because of limited understanding of the cumulative impact of multiple stressors. Models are ideal tools to aid understanding of future reef state under alternative management and climatic scenarios, but to date few have been sufficiently developed to be useful as decision support tools for local management of coral reefs subject to multiple stressors. We used a simulation model of coral reefs to investigate the extent to which the management of local stressors (namely poor water quality and fishing) might influence future reef state under varying climatic scenarios relating to coral bleaching. We parameterised the model for Bolinao, the Philippines, and explored how simulation modelling can be used to provide decision support for local management. We found that management of water quality, and to a lesser extent fishing, can have a significant impact on future reef state, including coral recovery following bleaching-induced mortality. The stressors we examined interacted antagonistically to affect reef state, highlighting the importance of considering the combined impact of multiple stressors rather than considering them individually. Further, by providing explicit guidance for management of Bolinao's reef system, such as which course of management action will most likely to be effective over what time scales and at which sites, we demonstrated the utility of simulation models for supporting management. Aside from providing explicit guidance for management of Bolinao's reef system, our study offers insights which could inform reef management more broadly, as well as general understanding of reef systems

Arginine catabolism by sourdough lactic acid bacteria: purification and characterization of the Arginine Deiminase (ADI) pathway enzymes from Lactobacillus sanfranciscensis CB1

The cytoplasmic extracts of 70 strains of the most frequently isolated sourdough lactic acid bacteria were screened initially for arginine deiminase (ADI), ornithine transcarbamoylase (OTC), and carbamate kinase (CK) activities, which comprise the ADI (or arginine dihydrolase) pathway. Only obligately heterofermentative strains such as Lactobacillus sanfranciscensis CB1; Lactobacillus brevis AM1, AM8, and 10A; Lactobacillus hilgardii 51B; and Lactobacillus fructivorans DD3 and DA106 showed all three enzyme activities. Lactobacillus plantarum B14 did not show CK activity. L. sanfranciscensis CB1 showed the highest activities, and the three enzymes were purified from this microorganism to homogeneity by several chromatographic steps. ADI, OTC, and CK had apparent molecular masses of ca. 46, 39, and 37 kDa, respectively, and the pIs were in the range of 5.07 to 5.2. The OTCs, CKs, and especially ADIs were well adapted to pH (acidic, pH 3.5 to 4.5) and temperature (30 to 37°C) conditions which are usually found during sourdough fermentation. Internal peptide sequences of the three enzymes had the highest level of homology with ADI, OTC, and CK of Lactobacillus sakei. L. sanfranciscensis CB1 expressed the ADI pathway either on MAM broth containing 17 mM arginine or during sourdough fermentation with 1 to 43 mM added arginine. Two-dimensional electrophoresis showed that ADI, OTC, and CK were induced by factors of ca. 10, 4, and 2 in the whole-cell extract of cells grown in MAM broth containing 17 mM arginine compared to cells cultivated without arginine. Arginine catabolism in L. sanfranciscensis CB1 depended on the presence of a carbon source and arginine; glucose at up to ca. 54 mM did not exert an inhibitory effect, and the pH was not relevant for induction. The pH of sourdoughs fermented by L. sanfranciscensis CB1 was dependent on the amount of arginine added to the dough. A low supply of arginine (6 mM) during sourdough fermentation by L. sanfranciscensis CB1 enhanced cell growth, cell survival during storage at 7°C, and tolerance to acid environmental stress and favored the production of ornithine, which is an important precursor of crust aroma compounds

Biodiversity of lactic acid bacteria isolated from spontaneously fermented amaranth and quinoa sourdoughs

Domesticated by pre-Hispanic cultures, quinoa (Chenopodium quinoa) and amaranth (Amaranthus caudatus) crops have been used for feeding of the Andean population since at least 3000 years. These ancestrally grown grains have recently attracted consumer's attention due to their high protein content, nutritional value and gluten-free characteristics. This is the first study to report the isolation and characterization of LAB species from spontaneously fermented Andean amaranth and quinoa

Definition of functional groups modelled, with example taxa from the Indo-Pacific region.

<p>Definition of functional groups modelled, with example taxa from the Indo-Pacific region.</p