An In Silico Approach to Enzymatic Synthesis of Fucooligosaccharides Using α-L-Fucosidase from Thermotoga maritima

Abstract: Fucooligosaccharides comprise the primary group of human milk oligosaccharides. Due to their beneficial properties, a series of synthetic methods have been proposed to obtain them. Enzy- matic methods show great promise, and α-L-fucosidase from Thermotoga maritima has emerged as a powerful catalyst for their production. Nonetheless, the enzyme’s limited substrate scope has de- layed its wider application. The present work aims to compare the relative reactivity of fucose, pNP-fucose, and ethyl-fucose, while also exploring the molecular interactions of these fucosyl-donors with the enzyme through a combination DFT and docking analysis. The HOMO-LUMO band gaps range from −7.14571 to −4.24429 eV, with α/β-pNP-fucose and α-fucose being the three most reactive compounds. Moderate association energies between −6.4 to −5.5 kcal·mol−1 were found in the dock- ing analysis, with α-pNP-fucose and both anomers of ethyl-fucose demonstrating the poorest affinity. In the case of α/β-lactose affinity to the β-fucose/enzyme complex, no significant differ- ences were shown. We conclude that the best fucosyl-donors for transfucosylation are those that maintain an enzyme affinity and reactivity similar to pNP-fucose

Thymol and carvacrol determination in a swine feed organic matrix using Headspace SPME-GC-MS

En los últimos años, el aceite esencial de orégano se ha utilizado como aditivo en alimentos para animales debido a sus propiedades antifúngicas y antibacterianas, así como sustituto sintético de antibióticos. Es deseable desarrollar un método rápido y efectivo de cuantificación de timol y carvacrol en una matriz orgánica de alimento para cerdo. En este trabajo se realiza una comparación de rendimiento entre la técnica de extracción con disolvente Soxhlet utilizando éter de petróleo y acetato de etilo y la técnica de microextracción en fase sólida en el espacio de cabeza (HS-SPME). Se realizó un diseño de experimentos 24 para definir los parámetros de HS-SPME: temperatura de equilibrio de 40 °C, temperatura de extracción de 40 °C, fuerza iónica de 0.57 M y tiempo de extracción de 40 min. El método HS-SPME es más eficiente para la extracción de timol y carvacrol de una matriz orgánica. Los límites de los valores de detección y cuantificación utilizando la extracción Soxhlet con acetato de etilo fueron de 3.7 y 12.5 μl-1 para timol y de 1.4 y 4.7 μg l-1 para carvacrol, respectivamente; mientras que el LDD y el LDC para HS-SPME fueron de 0.9 y 3.1 μg L-1 para timol y de 0.6 y 1.9 μg L-1 para carvacrol, respectivamente. El método de microextracción en fase sólida en el espacio de cabeza tiene el potencial de control de calidad en la industria para compuestos activos presentes en el aceite esencial de orégano como aditivo en una matriz orgánica.In recent years, oregano essential oil has been used as an animal food additive due to its antifungal and antibacterial properties as well as s synthetic antibiotic substitute. It is desirable to develop fast and effective thymol and carvacrol quantification method in a swine feed organic matrix. In this work, a performance comparison between the Soxhlet solvent extraction technique using petroleum ether and ethyl acetate and the head space-solid phase microextraction (HS-SPME) technique is made. A 24 design of experiments is performed for defining HS-SPME parameters: equilibrium temperature of 40 ºC, extraction temperature of 40 ºC, ionic strength of 0.57 M, and extraction time of 40 min. The HS-SPME method is more efficient for extracting thymol and carvacrol extraction from an organic matrix. Limits of detection and quantification values using Soxhlet extraction with ethyl acetate were 3.7 and 12.5 μL-1 for thymol and 1.4 and 4.7 μg L-1 for carvacrol, respectively; while LOD and LOQ for HS-SPME were 0.9 and 3.1 μg L-1 for thymol and 0.6 and 1.9 μg L-1 for carvacrol, respectively. The head space-solid phase microextraction method has the potential for quality control in the industry for active compounds present in oregano’s essential oil as an additive into an organic matrix

"Navajita Cecilia" Bouteloua gracilis h.b.k (lag.). nueva variedad de pasto para zonas áridas y semiáridas

Blue grama, Bouteloua gracilis H.B.K. (Lag.), can be found practically everywhere in the Chihuahuense desert, comprising nearly all the south-central States of the USA, Arizona, Texas and New Mexico(1), the north-central states of Mexico (Chihuahua, Coahuila, Durango, Nuevo León, San Luis Potosí and Zacatecas)(2,3) and even the States of Guanajuato, Hidalgo and Querétaro in the centralEl pasto navajita, Bouteloua gracilis H.B.K (Lag.) está distribuido prácticamente en todo el desierto Chihuahuense, que comprende desde los estados sureÅ„,,os de los Estados Unidos de América, Arizona, Texas y Nuevo México(1), los estados del norte centro del paí­s (Chihuahua, Coahuila, Nuevo León, Durango, Zacatecas y San Luis Potosí­)(2,3) y hasta la región central de México, delimitada por los estados de Hidalgo, Querétaro y Guanajuato(2,4)

La ganadería ante escenarios complejos.

La calidad de las contribuciones, producto de la pluma de especialistas en los temas tratados, el presente es un libro que esperamos, basándonos en la importancia de los temas tratados, sea de utilidad y abone a la reflexión de los estudiosos de la ganadería mexicana y, por supuesto, en beneficio de las familias ganaderas y de los consumidores de sus productos.este libro refleja en muchos sentidos la situación de la ganadería mexicana, a la que se le están demandando mayor producción y productividad, que los procesos productivos tengan la menor huella ecológicposible, que los alimentos sean inocuos, que se abatan costos de producción y, cada vez aumentan las presiones de diversos grupos para, que se incluyan los protocolos de bienestar animal, solamente por citar algunos de los retos que tiene. Algunas de estas demandas son complementarias, otras se contraponen, lo que hace valiosos a los estudios que desde las ciencias sociales se realizan y, desde diversas ópticas, se hagan propuestas de política pública balanceadas que consideren lo mejor de cada enfoque, pero sin desechar por completo los antagónicos.Universidad Autónoma Chaping

Experimental and modelling study of 1-pentene combustion at fuel-rich conditions

González Alatorre G, Böhm H, Atakan B, Kohse-Höinghaus K. Experimental and modelling study of 1-pentene combustion at fuel-rich conditions. Zeitschrift für physikalische Chemie. 2001;15:981-995.A fuel-rich, non-sooting (C/O = 0.773) 1-pentene/oxygen/argon flame is studied experimentally at 50 mbar. The results are compared to computations. The calculations show satisfactory agreement with the data obtained from the measurements. The main channels for 1-pentene decomposition are presented and discussed in view of previous data for a propene flame at similar experimental conditions. Special emphasis is directed towards the formation of the first aromatic ring and the further growth of small aromatic hydrocarbons. By reaction flow analysis, it is found that the major reaction channel for benzene formation results from the recombination of propargyl radicals. Furthermore, the major reaction channels for naphthalene formation are presented

Concentration and temperature measurement in fuel-rich flames

Kohse-Höinghaus K, Kamphus M, González Alatorre G, Atakan B, Schocker A, Brockhinke A. Concentration and temperature measurement in fuel-rich flames. COMPTES RENDUS DE L ACADEMIE DES SCIENCES - SERIE IV - PHYSIQUE ASTROPHYSIQUE. 2001;2(7):973-982.Soot formation is still one of the most pressing problems in combustion. Chemical mechanisms have been established which need to be examined in detail under laboratory conditions. Some of the main pathways concerning the formation of soot precursors are still under debate. While it seems commonly accepted that some of the dominant routes may be fuel-specific. experimental data and their comparison with kinetic models for fuels with more than 3 C atoms are scarce. This article will present an overview of the work pursued in Bielefeld on the characterisation of fuel-rich flames by a combination of laser spectroscopy and mass spectrometry. (C) 2001 Academie des sciences/Editions scientifiques et medicales Elsevier SAS

Contributions to the investigation of reaction pathways in fuel-rich flames

Kohse-Höinghaus K, Atakan B, Lamprecht A, et al. Contributions to the investigation of reaction pathways in fuel-rich flames. PHYSICAL CHEMISTRY CHEMICAL PHYSICS. 2002;4(11):2056-2062.Development and validation of detailed reaction mechanisms for fuel-rich combustion have a continuing need for quantitative experimental flame data. In this study, an overview is presented of recent experimental investigations of a series of fuel-rich premixed low-pressure flames burning acetylene, propene, linear and cyclic C-5-alkenes and C-5-alkanes with a combination of laser spectroscopy and molecular beam mass spectrometry (MBMS). Particular attention was devoted to the reaction pathways leading to the first aromatic ring. Fuel-specific c aspects with respect to benzene formation are discussed. The potential of resonance-enhanced multiphoton ionisation (REMPI) MBMS as a quantitative technique for the measurement of stable species is examined for benzene as an example. Also, first results of the investigation of a fuel-rich ethanol flame under similar conditions are given. Advantages and potential drawbacks of the applied diagnostic methods are discussed in view of the importance of reliable, quantitative measurements for the understanding of fuel-rich chemistry preceding polycyclic aromatic hydrocarbon (PAH) and soot formation as well as for the related modelling of these chemical processes

“Banderilla Diana” Bouteloua curtipendula (Michx.) Torr., nueva variedad de pasto para zonas áridas y semiáridas

El pasto banderilla, Bouteloua curtipendula (Michx.) Torr., es una gramínea perenne, originaria de América, que se encuentra distribuida desde Canadá hasta Argentina(2,3,4).El pasto banderilla crece en sitios ubicados entre 800 y 2400 msnm, siendo característico de las zonas áridas y semiáridas, en pastizales naturales, asociado a matorrales y bosques demezquite y huizache(3), se desarrolla bien en suelos francos y franco arenosos(5). Existe amplia variación morfológica en los ecotipos estudiados de pasto banderilla de las zonas áridas y semiáridas de México, lo que hace posible la identificación de ecotipos sobresalientes con características forrajeras deseables para la selección y mejoramiento genético de este pasto(6); esto enfatiza la necesidad de evaluar, seleccionar, mejorar,reproducir y registrar material forrajero nativo de México(7). Entre las especies nativas, el pasto banderilla es uno de los preferidos por el ganado y es ampliamente utilizado en resiembras(8,9)

An In Silico Approach to Enzymatic Synthesis of Fucooligosaccharides Using α-l-Fucosidase from Thermotoga maritima

Fucooligosaccharides comprise the primary group of human milk oligosaccharides. Due to their beneficial properties, a series of synthetic methods have been proposed to obtain them. Enzymatic methods show great promise, and α-l-fucosidase from Thermotoga maritima has emerged as a powerful catalyst for their production. Nonetheless, the enzyme’s limited substrate scope has delayed its wider application. The present work aims to compare the relative reactivity of fucose, pNP-fucose, and ethyl-fucose, while also exploring the molecular interactions of these fucosyl-donors with the enzyme through a combination DFT and docking analysis. The HOMO-LUMO band gaps range from −7.14571 to −4.24429 eV, with α/β-pNP-fucose and α-fucose being the three most reactive compounds. Moderate association energies between −6.4 to −5.5 kcal·mol−1 were found in the docking analysis, with α-pNP-fucose and both anomers of ethyl-fucose demonstrating the poorest affinity. In the case of α/β-lactose affinity to the β-fucose/enzyme complex, no significant differences were shown. We conclude that the best fucosyl-donors for transfucosylation are those that maintain an enzyme affinity and reactivity similar to pNP-fucose

Influence of Oat β-Glucan on the Survival and Proteolytic Activity of Lactobacillus rhamnosus GG in Milk Fermentation: Optimization by Response Surface

β-glucans come from cereals that have been located within compounds with prebiotic activity. They have presented several bioactivities that have determined their high functional value. The aim of this study was to identify the influence of oat β-glucan on the survival and proteolytic activity of Lactobacillus rhamnosus GG in a milk fermentation through an experimental design to optimize the process. For β-glucan extraction after dry milling of oats, two methods were applied: with and without enzymatic inactivation of the semolina. The highest extraction yield (45.25 g/L) was obtained with enzymatic inactivation. For the optimization of survival and proteolytic activity, a central design composed of axial points with two factors on three levels was used. Control factors were β-glucan and inoculum concentrations. According to response surface, the best survival growth rate of probiotic was observed with 4.38% of inoculum and 22.46 g/L of β-glucan, and the highest production of free amino groups was observed with 4.18% of inoculum and 22.71 g/L of β-glucan. Thus, β-glucan promotes the proteolytic activity of Lb. rhamnosus GG in milk fermentation