β-glucan molecular weight

fraction of the HMW-BG sample were eluted in the void volume of the size exclusion columns, i.e. the β-glucan added to the gluten-free doughs had a Mp > 9 x 10 5 Da. However, for the β-glucans isolated from the control bread made from the untreated rice flour there was a large reduction in Mp, as the main eluting peak was ~ 0.23 x 10 5 Da, presumably due to polysaccharide degradation by endogenous β-glucanases of the rice flour during the breadmaking process (Table 1). Similarly, several researchers have previously noted a considerable reduction of β-glucan molecular weight during production of yeast-leavened bakery products from oat bran as well as rye and barley flour which was attributed to endogenous β-glucanase activity (Aman et al. 2004; Andersson et al. 2004; 2008; 2009; Lazaridou et al. 2014; Trogh et al. 2004); apparently, the molecular weight of β-glucans in the final products decreases with increasing mixing and dough fermentation time. Recently, an endogenous β-glucanase activity was also found in rice flour (Perez-Quirce et al. 2016) which can cause severe reduction of oat and barley β-glucans during breadmaking when these polysaccharides are added as concentrates to rice-based gluten-free bread formulations (Ronda et al. 2015).

Rice flour (12.5% moisture, 0.46% ash, 7.5% protein, 0.49% fat, and 79.1% starch, particle size distribution: 6%>150 mm, 150 mm>63.2%>100 mm, and 30.8%<100 mm) was supplied by Herba Ricemills S.L.U (Tarragona, Spain). Salt, sugar, and sunflower oil were purchased from the local market. The HPMC 4 KM was a gift from Dow Chemical (Midland, Michigan, USA). (1→3)(1→6)-β-glucans (BG) used in dough and bread formulations were of three types. Two of them were obtained from the yeast Saccharomyces cerevisiae: one water insoluble (IBG) (Wellmune WGP® Dispersible Powder) and the other soluble (SBG) (Wellmune Soluble Powder®); Biothera (Eagan, Minnesota, USA) provided both as free samples. Wellmune WGP® consists of the purified yeast beta-glucan from the cell wall of baker’s yeast. The natural form is a small spherical particle 2-4 microns in diameter. The second form, Wellmune Soluble Powder®, has a wide range of molecular weights ranging from a few thousand Daltons to several million Daltons, with an average molecular weight of 100 – 150kDa (information provided by the supplier). The third BG, insoluble (FBG), was derived from the fungus Pleurotus ostreatus (Pleuran), given as a gift by Pleuran, s.r.o. (Bratislava, Slovak Republic);

 -glucan extraction using hot water as solvent is influenced by a large number of parameters affecting mass transfer steps (external transport and internal diffusion) and equilibrium. All of them were considered in this work, unlike previous published works. Several experiments were performed in order to study the influence of them and to obtain useful engineering information. The initial experiments were useful to find 55°C as the optimal temperature and to scorn pH as a critical variable for the -glucan extraction process. From all the parameters included in the Taguchi’s experimental design, it was demonstrated that particle size has a significantly higher influence on the extraction process than the other parameters studied (stirring rate, extraction time and barley variety), indicating that mass transfer steps are limiting the overall extraction process. In order to get satisfying results, it is mandatory to perform the extraction from small particle size flour. Solvent to flour ratio, although the statistical analysis performed revealed that its effect was statistically significant, in practical terms can be concluded that it is not a critical factor affecting the process. The final decision on the selection of the level of this parameter will be made considering the later purification step, since a lower amount of water during the extraction, simplifies and reduces operating costs in the subsequent  -glucan concentration process. The results obtained for the two tested barleys had the same trend; which means that the proposed operating conditions can be extrapolated to other barley cultivars. Finally, those results obtained under the optimal conditions revealed a higher extraction yield for the two varieties of barley selected in this work compared with those reported by other researchers, which means that these varieties of barley grown up at the Castilla y León region (Spain), are excellent raw materials for β-glucan obtention.

Β-glucans are homopolysaccharides of high molecular weight glucose found in plants such as cereals and in the walls of fungi and yeasts, this makes β-glucans have particular behaviors on the health of animals, the poultry sector presents High population densities under intensive confinement regimes which directly affects the health status of animals, thus increasing their stress. For this particular investigation the objective was to evaluate the effect of dietary addition of yeast β-glucans on the immune response in laying birds of the 33-week-old white Lohmann line in the municipality of Jamundí, Valle del Cauca, three groups of which were serologically Elisa-type tests were performed at 20 birds per group before and after administration with yeast β-glucan (Saccharomyces cerevisia) in the diet, and two of these groups in Half of the experimental period they were given a vaccine against Newcastle + Bronchitis. Although there was no influence on the production of post-vaccinal antibodies with the introduction of β-glucan, a positive effect of β-glucan was shown to be able to reduce the coefficient of variation of the vaccine in both diseases, becoming an important finding to improve the Efficiency of conventional vaccine plans.

Barley (1→3)(1→4)- β-D-glucan (BBG)(Glucagel™), a low Mw BG, was given as a free sample from DKSH (Hamburg, Germany). The oat (1→3)(1→4)- β-D-glucan concentrate (OBG) (Promoat™) which was a high Mw BG preparation, was supplied by Biovelop AB (Kimstad, Sweden). The proximate composition of these materials as given by the suppliers was: for BBG, 2.52 g/100 g moisture, 4.75 g/100 g soluble protein, 1.43 g/100 g ash, 1.32 g/100 g fat, >85 g/100 g total carbohydrates, and >72 g/100 g BG; for OBG, 6 g/100 g moisture, 54-56 g/100 g carbohydrates (dextrin), <4.5 g/100 g protein, 1-3 g/100 g ash and 0.5-1 g/100 g fat, and 33-36 g/100 g BG. The gluten content of the commercial BBG and OBG samples was analyzed by the ELISA test based on the R5 antibody; for OBG, the gluten content was under the detection limit (<6.2 mg/kg), while for BBG 1.76 g/kg, which rendered the latter BG concentrate as not gluten-free. Nevertheless, the BBG was included in this study as a raw material for evaluation of the effect of BG Mw on the rice flour-based gluten- free dough formulations since it is technically feasible to obtain a gluten-free barley BG concentrate (Ronda et al., 2013).

, whereas amylase no differences were obtained significant between treatments. For non-specific immune system were reported significant differences in total protein over time, an increase in these 15 days, in all treatments it was obtained. The number of leukocytes increased significantly over time and the interaction between time and diet, which perform better in treatment with β-glucan was obtained. In the respiratory burst significant differences were obtained, with an increase to 35 and 45 days treatment with chitosan and inulin. For phagocytosis no statistically significant differences were obtained. Based on the results it is concluded that by including inulin 1% in the diet of the totoaba, this will have a higher digestibility due to increased enzymes trypsin and lipase. Moreover, the inclusion of the three prebiotics can improve certain parameters of non-specific immune response, so it is recommended to morphofunctional studies of the digestive tract to relate and understand these results.

una optimización geométrica mediante una minimización de energía. Además, la mecánica molecular es empleada para simular moléculas grandes, como las proteínas o el DNA, por su bajo costo computacional lo que no podría ser posible con otros métodos o herramientas [123]. Otra herramienta es la Dinámica Molecular, donde sus cálculos son aplicables en las leyes del movimiento clásico de las moléculas. Por otro lado, tenemos los cálculos Ab initio, los cuáles están basados en la ecuación de Schrödinger, y describen el comportamiento de los electrones y núcleos en una molécula. Al resolver esta ecuación nos permite determinar la energía de la molécula y su respectiva función de onda. Estos cálculos son relativamente lentos ya que emplean la mecánica cuántica básica, lo que las limita a trabajar con moléculas relativamente pequeñas. Los cálculos semiempíricos se parecen a los de ab initio, ya que se basan en la ecuación de Schrödinger, pero son parametrizados con valores experimentales; estos cálculos son más lentos que los de mecánica molecular, pero más rápidos que los cálculos de Ab initio. Por último se encuentran los cálculos de la Teoría del Funcional de la Densidad; son parecidos a los cálculos realizados por Ab initio y semiempíricos, dado que emplean la ecuación de Schrödinger, pero no calculan la función de onda, en su lugar derivan la distribución electrónica (función de la densidad del electrón) directamente [124].

Los resultados muestran que el rendimiento se ve favorecido incrementando la cantidad de catalizador (1.5 g). Reacciones de copolimerización hechas con 1 g de catalizador muestran la misma cantidad de producto que de subproducto. Reacciones llevadas a cabo con 0.3 y 0.6 g de catalizador tienen una producción casi insignificante. La cinética de reacción ha mostrado leves mejores resultados a una temperatura de 80 °C que a una temperatura de 60 °C porque las reacciones poliméricas toman 40 h, por lo que la cinética de reacción es lenta. La presión no participa en la ecuación cinética, ya que los resultados obtenidos por FITR en picos de productos y subproductos son similares después de cambiar la presión. El peso molecular final deseado y el tiempo de reacción deben también ser tenidos en cuenta en las reacciones de copolimerización. Un peso molecular esperado de reacción de 725 g/mol logra resultados no deseados. También las reacciones llevadas a cabo con un tiempo de reacción de 20h (la mitad del tiempo de reacción) han obtenido resultados satisfactorios.

protocols such as drying /trituration and washing, instead of β-glucan concentrates were used. Regarding gluten-free products, few studies have explored the use of these polysaccharides on the fortification of gluten-free cakes (Kim et al., 2011), rice noodles (Heo et al., 2014) and bread (Kittisuban et al., 2014). Kim et al. (2011) used β-glucan extracts from Lentinus edodes (insoluble fiber) as a high-fiber and low- calorie ingredient in wheat flour cakes and found an increase in batter viscosity with more pronounced shear-thinning behavior and enhanced elastic properties. Although no significant differences were observed between the control and cakes containing 1 g of yeast β-glucan per serving, a further increase of polysaccharide level resulted in decrease of the volume and increase of the hardness of cakes. Heo et al. (2014) obtained rice noodles with greater extensibility and firmness with Lentinus edodes fortification for all concentrations tested (4, 8 and 12%). Kittisuban et al. (2014) used response surface methodology to analyze effects of hydroxypropylmethylcellulose (HPMC), yeast β-glucan (insoluble), and whey protein isolate (WPI) on physical properties of gluten-free rice breads and found a decrease in bread volume and a increase in crumb hardness with increasing β-glucan concentration (from 1 g / 100 g to 2 g / 100 g). However, in this work the optimum level of added water to the dough was not investigated, which is considered one of the most important factors for optimization of the quality of the bread fortified with any fiber. In addition, fungi and yeast β-glucans exhibit differences in solubility, which may lead to different behavior in complex food matrices (Martinez et al., 2014); this fact has also to be considered in food fortification with microbial β-glucans. In general, incorporation of soluble fibers into bread formulations, such as inulin or polydextrose decrease the dough consistency, and favour a better bread development, darker breads, lower crumb hardness and higher cell density compared to control breads. In contrast, insoluble fibers from oat, bamboo, potato and pea, particularly those with coarse particle size, decreased the bread specific volume and increased largely the crumb firmness (Martinez et al., 2014).

Para comprender las actividades biológicas de las glucanas, además de conocer los mecanismos moleculares involucrados, es necesario también tener en cuenta que los mamíferos no poseen β-(1→3)-glucanasas que degraden rápidamente estas moléculas y su metabolismo mediante oxidación es muy lento, esto hace que permanezcan más tiempo en el organismo, hasta más de un mes pueden permanecer en el hígado y en el bazo. In vivo, el aclaramiento de las β-glucanas depende de su peso molecular; las de bajo peso se secretan mediante filtración glomerular, en tanto que las mayores son retenidas primeramente en el hígado y degradadas por las células de Kupffer, proceso que puede tomar varias semanas. 27,28 Se ha informado también que proteínas

El [Poli (R)-hidroxibutanoato] (P(3HB)) es el activo biopoliester sintetizado como reserva del material de carbón y de energía presente en algunos microorganismos procariotas. Fue descubierto P(3HB) y relacionado con los derivados [Poli (R)-3-hidroxibutanoatos]. Estos compuestos tienen un gran interés para la investigación básica y en las aplicaciones industriales debido a su biodegradabilidad y su biocompatibilidad lo cual permite que sean considerados sustitutos biodegradables del material plástico convencional. Li y otros [82] informaron resultados experimentales de RMN sobre los complejos entre 3HB, d3HD (el isómero D) y α - CD, - CD y -CD. Demostraron que los complejos obtenidos en forma selectiva entre dγHD y -CD mantienen una estequiometría 1 a 1 [82]. Sobre la base de los resultados obtenidos del análisis termodinámico, existen en este trabajo discusiones sobre cuáles son las principales contribuciones de las fuerzas de conducción a la formación de estos últimos complejos. Con la intención de aclarar estos ítems Castro y Jubert [83], recurriendo a métodos de mecánica molecular (MM) estudiaron teóricamente estos complejos. Se representaron todos los modelos posibles de los complejos anfitrión-huésped entre γHB, dγHD, α - CD, - CD y -CD usando MM+ [84] implementado por el HyperChem® package prediciendo que el complejo formado por dγHD y -CD es el más estable de todos.

En este trabajo, se ha analizado la variación alélica para gluteninas de alto peso molecular (HMW) en una colec- ción de 165 variedades tradicionales españolas de trigo blando (Triticum aestivum ssp. vulgare L.) provenientes del Centro Nacional de Recursos Fitogenéticos. La identificación mediante técnicas estándar de electroforesis se ha com- plementado con un método de análisis por PCR que ha permitido la identificación de la subunidad 2•• del locus Glu- A1 en varios cultivares. La relación entre la composición en gluteninas de alto peso molecular y la calidad panadera se ha analizado mediante la prueba del volumen de sedimenatción con SDS y los datos del mixógrafo. Se ha encon- trado una influencia positiva en la calidad por parte de la subunidad 2•• del locus Glu-A1, los pares de subunidades 7 + 8 y 13 + 16 del locus Glu-B1, y el par 5 + 10 del locus Glu-D1. Variedades con la misma composición en gluteni- nas de alto peso molecular han mostrado un amplio rango de valores en los parámetros de calidad, apuntando a la par- ticipación de otras prolaminas, como las gluteninas de bajo peso molecular, cuya influencia en la calidad será anali- zada en el futuro. En el presente trabajo, se incluye la descripción detallada de la composición en gluteninas de alto peso molecular y de parámetros de calidad de todos los cultivares analizados para su posible utilización en programas de mejora de trigo.

Among the A β neurotoxic mechanisms, oxidative stress and mitochondrial damage are two of the most cited effects of Aβ exposure. Several authors have suggested that the perivascular accumulation of A β damages the BBB, leading to microbleed- ings, inflammatory reactions, and subsequent damage to the neuronal network (Zlokovic, 2010; Popa-Wagner et al., 2013; Zolezzi and Inestrosa, 2013). On this regard, several authors have demonstrated the role of PPARs as an endothelial protective agents (Zhou et al., 2008; Bae et al., 2010; Kröller-Schön et al., 2013; Zarzuelo et al., 2013; d’Uscio et al., 2014; Hawkes et al., 2014). Recently, it has been demonstrated that PPARs are able to protect endothelial cells from oxidative damage, thus preventing vascular dysfunction, which could favor brain parenchyma alter- ations (d’Uscio et al., 2012; Papadopoulos et al., 2013). Based on current knowledge and on our own work, we have proposed that PPAR activation, through natural or synthetic ligands, could protect and recover BBB integrity and functionality by increas- ing cell antioxidant capacity and improving energy metabolism, leading to the increased expression of specific transporters that could influence the A β -clearance rate (Nicolakakis et al., 2008; Zolezzi and Inestrosa, 2013; Zolezzi et al., 2013b; Hawkes et al., 2014). Energy metabolism is vital for both, neurons and the BBB, primarily because the preservation of the ion gradients (in the case of neurons) and the traffic across the BBB requires large amounts of energy (Abbott et al., 2010; Liebner and Plate, 2010; Popa-Wagner et al., 2013).

electrónica de barrido (MEB) mostraron que la β -CD pura se presentaba en forma de pequeños fragmentos de forma irregular. A diferencia de la sustancia en polvo obtenida en la mezcla física, en los complejos preparados mediante amasado se obtuvieron microcristales de forma irregular. La etil- β -CD mostró la forma de una partícula de forma esférica porosa claramente definida. En la mezcla física se apreciaron muy pocas partículas irregulares y de forma esférica de rifampicina. En el complejo preparado mediante amasado, no apareció ninguna partícula de forma esférica; sólo se obtuvieron partículas homogéneas de forma irregular. Sin embargo, en el complejo preparado mediante disolvente común se obtuvieron partí- culas aplanadas de forma irregular diferentes a la rifampicina pura y a la etil- β -CD pura. Se produjo, por tanto, una modificación de la mor- fología de la β-CD pura en los complejos, que aparecen como componentes simples.

Objective: To present a case of a newborn with neonatal CSNT, to analyze the thrombophilic risk factors, and the management of cerebral venous thrombosis with low-molecular-weight hep[r]

Fucoidan was purchased as a dried powder from Kadoya & Co., Kobe, Japan (lot A03012) and extracted from cultured kelp C. okamuranus harvested off the coast of Okinawa Island, Japan [24]. The polysaccharide preparation was cer- tified to contain 90.4 % fucoidan (anthrone-sulfuric acid method) and to have a mean molecular weight of 92.1 kDa (HPLC method). The fucose and sulfate contents of fucoidan were 38.6 and 15.9 %, respectively, with ash comprising 19.6 % of the content and other sugars comprising 23 % (glucuronic acid and traces of xylose). Dried samples of fu- coidan were suspended in Dulbecco’s modified Eagle’s medium (DMEM) at a concentration of 2.5 mg/ml and filtered through a 0.22 mm membrane filter. Ribavirin (Vilonape- diatrica, Valeant, Me´xico) was used as an antiviral control. Cells culture and virus

Oligosaccharides  from several origins are being investigated to find applications  in  the  pharmaceutical field, mainly  as  precursors for  antitumoral  and  antiviral  drugs.  Heparin  has  been  used  for  many  years  as  anticoagulant,  and  for  this  reason  sulfated  oligoxylans were developed as anticoagulant heparin‐mimetics several decades ago. A  mixture  of  sulfated oligoxylans (in  this case  sulfated 1‐4‐β‐D‐oligoxylans  produced by  chemical  sulfation  of  beechwood)  mimics  most  other  biological  actions  of  natural  heparins  in  vitro,  including  inhibition  of  the  human  immunodeficiency  virus.  The  mechanism  is  not  clear,  but  the  results  suggest  that  certain  oligosaccharides  in  the  sulfated  xylan  preparation  have  structures  that  may  specifically  act  to  inhibit  the  reactions  between  the  virus  envelope  and  the  target  cell  membrane  [24].  Sulfated  xylogalactans  from  the  red  seaweed  Nothogenia  fastigiata  [25]  and  a  xylomannan  derived  from  algal  [26]  demonstrated  antiviral  activity  against  herpes  simplex  virus  types  1  and  2.  A  polysaccharide  mixture  (formed  by  glucose,  xylose,  mannose  and  glucuronic  acid)  obtained  from  marine  algae  has  antiviral  activity,  and  when  it  is  bounded  to  a  protein,  both  (the  original  polysaccharide  and  this  complex)  act  as  a  biological  response  modifier,  exerting  a  great  influence  on  the  immune  system.  They  have an  inhibiting  activity  against  adsorption  of  HIV on human‐derived  lymphocytes  and also,  inhibit the  activity of reverse  transcriptase, which is  an  enzyme  essential  for  the proliferation of HIV [27].  

In this study, influence of the molecular weight of that cationic electrolyte - Polyethylenimine - (used to give the ZnO particles a positive charge potential and good dispersion in aq[r]

Another weighting function proposed here is based on the work of Shepard [16], who argues for a universal perceptual law which states that the relevance of a previous stimulus for the generalization to a new stimulus is an exponentially decreasing function of its distance in psychological space. This gives the weighted voting function of Eq. 4, where α and β are constants and determine the slope and the power of the exponential decay function.

En la Figura 3.7 se observa la desviación media cuadrática (RMSD) de la estructura de Beta amiloide determinada con el programa GROMAC´S, utilizando los datos obtenidos a partir de la dinámica molecular, en la cual se muestra que está dentro del rango de los 0.3nm lo cual es indicativo de que la Beta amiloide se encuentra estable a partir de los 3 ns hasta los 100 ns; con este dato se pudo calcular la estructura promedio para usarla en el análisis de acoplamiento molecular (Docking). Además, se determinó la fluctuación de la desviación media cuadrática (RMSF) (ver Figura 3.8), en donde se observa que los aminoácidos que tiene mayor fluctuación son las asparraginas (ASP), aminoácido con el que inicia cada monómero y algunas que se encuentran dentro de la estructura, esto es dado a que la asparragina ayuda a la formación de las láminas beta, teniendo como consecuencia la formación de puentes hidrógeno entre los monómeros del dodecámero de la Beta amiloide.