Phenylpropanoid Glycoside Analogues: Enzymatic Synthesis, Antioxidant Activity and Theoretical Study of Their Free Radical Scavenger Mechanism

Phenylpropanoid glycosides (PPGs) are natural compounds present in several medicinal plants that have high antioxidant power and diverse biological activities. Because of their low content in plants (less than 5% w/w), several chemical synthetic routes to produce PPGs have been developed, but their synthesis is a time consuming process and the achieved yields are often low. In this study, an alternative and efficient two-step biosynthetic route to obtain natural PPG analogues is reported for the first time. Two galactosides were initially synthesized from vanillyl alcohol and homovanillyl alcohol by a transgalactosylation reaction catalyzed by Kluyveromyces lactis β-galactosidase in saturated lactose solutions with a 30%–35% yield. To synthesize PPGs, the galactoconjugates were esterified with saturated and unsaturated hydroxycinnamic acid derivatives using Candida antarctica Lipase B (CaL-B) as a biocatalyst with 40%–60% yields. The scavenging ability of the phenolic raw materials, intermediates and PPGs was evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) method. It was found that the biosynthesized PPGs had higher scavenging abilities when compared to ascorbic acid, the reference compound, while their antioxidant activities were found similar to that of natural PPGs. Moreover, density functional theory (DFT) calculations were used to determine that the PPGs antioxidant mechanism proceeds through a sequential proton loss single electron transfer (SPLET). The enzymatic process reported in this study is an efficient and versatile route to obtain PPGs from different phenylpropanoid acids, sugars and phenolic alcohols

Molecular Characterization of Inulosucrase from Leuconostoc citreum: a Fructosyltransferase within a Glucosyltransferase

The gene coding for inulosucrase in Leuconostoc citreum CW28, islA, was cloned, sequenced, and expressed in Escherichia coli. The recombinant enzyme catalyzed inulin synthesis from sucrose like the wild-type enzyme. Inulosucrase presents an unusual structure: its N-terminal region is similar to the variable region of glucosyltransferases, its catalytic domain is similar to fructosyltransferases from various microorganisms, and its C-terminal domain presents similarity to the glucan binding domain from alternansucrase, a glucosyltransferase from Leuconostoc mesenteroides NRRL B-1355. From sequence comparison, it was found that this fructosyltransferase is a natural chimeric enzyme resulting from the substitution of the catalytic domain of alternansucrase by a fructosyltransferase. Two different forms of the islA gene truncated in the C-terminal glucan binding domain were successfully expressed in E. coli and retained their ability to synthesize inulin but lost thermal stability. This is the first report of an inulosucrase bearing structural features of both glucosyltransferases and fructosyltransferases

Estudio de una fructusiltransferasa de Aspergillus niger en la síntesis de fruto oligosacaridos

IP 1101-12-025-97de Ciencias Quimico-Farmaceuticas. -- Vol. 27 (1998); p.53-56--ISSN 00347418.;ARTICULO(S): EN REVISTA: Produccion y caracterizacion de extractos enzimaticos crudos con actividad de;fructosiltransferasa. / Camilo E. La Rotta, Sonia A. Ospina, Agustin Lopez'-Munguia. -- en: Revista colombian

Comportamiento productivo y reproductivo al parto y al destete en cerdas de siete líneas genéticas

For a sustainable management of grazing lands,  is necessary to know the  strategy of nature to sustain the grassland,in  consequence,  the  management  schemes  must  be  based  in  programs  related  to  an  environmental  characterizationand  adequate monitoring.  With  the aim  to  develop a  tool  to support  the  diagnosis  of  grasslands,  we  hereby  proposethe  application  of  the  Hydro-Environmental  Availability  Index  (HEAI),  with  scale  from  0  to  10.  According  to  theapplication of HEAI in 36 localities of Sonora, Mexico, five of them (13.9 %) fluctuated from 0 to 2.5, in consequence,their  grasslands  are  highly  vulnerable  to  drought,  with  very  low  possibilities  for  management.  Twenty  (55.6  %)oscillated from 2.5 to 5, suggesting a management with severe restrictions. Eleven (30.5 %) fluctuated from 5 to 7.5,proposing a sustainable management with adequate rotations and preventions during a drought, and none of localitiesreached  values  for  HEAI  >  7.5,  high  potential  for  sustainable  management,  with  appropriate  rotations.  It  must  beconsidered that the actions to prevent the effects of overgrazing, not always are enough to mitigate the overwhelmingconsequences  of  droughts,  which  are  exacerbated  by  climate  change.El objetivo del estudio fue evaluar los efectos de línea genética (LG), número de parto (NP) y sala de parto (S) en el tamaño de la camada nacida viva (TCNV), el número de lechones nacidos muertos por camada (LNM), el tamaño de la camada al nacimiento (TCN) y al destete (TCD), los pesos de la camada al nacimiento (PCN) y al destete (PCD), el consumo diario de alimento de la cerda (CDA) y las pérdidas de peso (PPL) y grasa dorsal (PGD) de la cerda en la lactancia. Además de los efectos fijos LG, NP y S, el modelo incluyó las covariables TCN para PCN y TCD para PCD. Se encontraron diferencias (P<0.0026) entre LG para TCN, TCNV, LNM y CDA. El NP sólo fue significativo (P<0.0001) para CDA, S sólo lo fue (P<0.0380) para LNM. Las cerdas de tres o más partos tuvieron mayor CDA (4.5 ± 0.2 kg) que las de primero o segundo partos (3.4 ± 0.2 kg). Se requiere reforzar la atención al parto y durante la lactanciapara reducir la muerte de lechones al parto y en la lactancia; así como evitar que la cerda pierda demasiado peso y grasa dorsal con el fin de reducir el deterioro del comportamiento productivo y reproductivo postdestete

Inclusión del coeficiente de consanguinidad en los modelos de evaluación genética de bovinos Jersey y Suizo americano en México

The inclusion of the inbreeding coefficient (F) into the models to predict breeding values (BV) for Jersey (J) and Brown Swiss (BS) Mexican registered dairy cattle was studied. The conventional model including the fixed effect of herd-year-season, and the genetic additive and permanent environmental random effects was compared to an alternative model that additionally included F. Traits analyzed in J were the yields per lactation of milk (MY), fat (FY) and protein (PY), and the percentages of fat (%F) and protein (%P) in milk. In BS only MY was analyzed. The analyses were done using an animal model and the MTDFREML program, pedigree files included 21026 and 101861 animals in J and BS. Several criteria to compare results from the alternative models were used. The most notorious change was for the BV for %P in J, the BV for the other traits they were similar in both breeds. Coincidence among the top 100 sires from the two models ranged from 90 to 98 %. Regression coefficients of BV and their accuracies from the conventional model on the BV and their accuracies from the alternative model were around 1.0 in both breeds. The estimates of the genetic variance and h2 obtained with both models remained essentially the same for all traits in both breeds. The results suggest that the inclusion of F into the models to evaluate genetically Jersey and Brown Swiss purebred Mexican dairy cattle is not necessary. However, it is required to perform this evaluation when the average for F is higher than it is today.Se estudió el efecto de incluir el coeficiente de consanguinidad del animal (F) en los modelos para la evaluación genética de bovinos mexicanos Jersey y Suizo Americano de registro. El modelo sin el efecto de consanguinidad que incluyó el efecto fijo de hato-año-estación y los aleatorios genético directo y de ambiente permanente, se comparó con otro donde además se incluyó F como covariable. Las características analizadas en Jersey fueron las producciones por lactancia de leche (PL), grasa (PG) y proteína (PP), y los porcentajes de grasa (%G) y proteína (%P) en leche, mientras que en Suizo Americano sólo se analizó la PL. Los pedigríes incluyeron 21,026 animales Jersey y 101,861 Suizo Americano. El cambio más notorio correspondió a los valores genéticos predichos (VGP) para %P en Jersey, los VGP para las demás características fueron similares en ambas razas. Los porcentajes de coincidencia entre los 100 sementales superiores evaluados con ambos modelos variaron de 90 a 98%. Los coeficientes de regresión de los VGP y de exactitudes obtenidos con el modelo sin el efecto de la consanguinidad sobre los del modelo con el efecto de consanguinidad fluctuaron alrededor de 1.0 en ambas razas. Los estimados de las varianzas genéticas y de h2 obtenidos con ambos modelos fueron similares para todas las características. No se considera necesaria la inclusión de F en los modelos para evaluar genéticamente las poblaciones estudiadas, sin embargo, se recomienda realizar nuevamente este estudio cuando el promedio de F sea mayor que el actual

Glycosyltransferases Expression Changes in <i>Leuconostoc mesenteroides</i> subsp. <i>mesenteroides</i> ATCC 8293 Grown on Different Carbon Sources

Leuconostoc mesenteroides strains are common contributors in fermented foods producing a wide variety of polysaccharides from sucrose through glycosyltransferases (GTFs). These polymers have been proposed as protective barriers against acidity, dehydration, heat, and oxidative stress. Despite its presence in many traditional fermented products and their association with food functional properties, regulation of GTFs expression in Ln. mesenteroides is still poorly understood. The strain Ln. mesenteroides ATCC 8293 contains three glucansucrases genes not found in operons, and three fructansucrases genes arranged in two operons, levLX and levC-scrB, a Glycoside-hydrolase. We described the first differential gene expression analysis of this strain when cultivated in different carbon sources. We observed that while GTFs are expressed in the presence of most sugars, they are down-regulated in xylose. We ruled out the regulatory effect of CcpA over GTFs and did not find regulatory elements with a direct effect on glucansucrases in the condition assayed. Our findings suggest that only operon levLX is repressed in xylose by LexA and that both fructansucrases operons can be regulated by the VicK/VicR system and PerR. It is essential to further explore the effect of environmental conditions in Ln. mesenteroides bacteria to better understand GTFs regulation and polymer function