Escuela Nacional de Ciencias Biologicas del IPN

Ejido Plan de Ayala, Mexico

Escuela Nacional de Ciencias Biologicas del IPN

Ejido Plan de Ayala, Mexico
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Bartolo-Aguilar Y.,CINVESTAV | Dendooven L.,CINVESTAV | Chavez-Cabrera C.,CINVESTAV | Flores-Cotera L.B.,CINVESTAV | And 3 more authors.
AMB Express | Year: 2017

The production of recombinant biopharmaceutical proteins is a multi-billion dollar market. Protein recovery represents a major part of the production costs. Pichia pastoris is one of the microbial systems most used for the production of heterologous proteins. The use of a cold-induced promoter to express lytic enzymes in the yeast after the growth stage could reduce protein recovery costs. This study shows that a cold-shock can be applied to induce lysis of the yeast cells. A strain of P. pastoris was constructed in which the endogenous eng gene encoding a putative endo-β-1,3-glucanase was overexpressed using the cold-shock induced promoter of the cctα gene from Saccharomyces cerevisiae. In the transgenic P. pastoris, the expression of eng increased 3.6-fold after chilling the cells from 30 to 4 °C (cold-shock stage) followed by incubation for 6 h (eng expression stage). The culture was heated to 30 °C for 6 h (ENG synthesis stage) and kept at 37 °C for 24 h (lysis stage). After this procedure the cell morphology changed, spheroplasts were obtained and cellular lysis was observed. Thus, a clone of P. pastoris was obtained, which undergoes autolysis after a cold-shock. © 2017, The Author(s).

Gonzalez-Hernandez A.,CINVESTAV | Munoz-Islas E.,Instituto Nacional Of Perinatologia | Lozano-Cuenca J.,CINVESTAV | Ramirez-Rosas M.B.,CINVESTAV | And 4 more authors.
European Journal of Pharmacology | Year: 2010

The importance of calcitonin gene-related peptide (CGRP) in the regulation of vascular tone has been widely documented. Indeed, stimulation of the perivascular sensory outflow in pithed rats results in vasodepressor responses, which are mediated by CGRP release. These vasodepressor responses are inhibited by clonidine via prejunctional α2A/2C-adrenoceptors, but no study has yet reported the role of prejunctional 5-hydroxytryptamine (5-HT) receptors in this experimental model. Since activation of prejunctional 5-HT1 receptors results in inhibition of neurotransmitter release, this study sets out to investigate as an initial approach the role of 5-HT1B receptors in the inhibition of the vasodepressor sensory outflow in pithed rats. Male Wistar pithed rats were pretreated with hexamethonium (2mg/kg.min) followed by i.v. continuous infusions of methoxamine (20μg/kg.min), and then by saline (0.02ml/min) or CP-93,129 (a rodent 5-HT1B receptor agonist; 0.1, 1 and 10μg/kg.min). Under these conditions, electrical stimulation (0.56-5.6Hz; 50V and 2ms) of the spinal cord (T9-T12) resulted in frequency-dependent decreases in diastolic blood pressure. The infusions of CP-93,129, as compared to those of saline, inhibited the vasodepressor responses induced by electrical stimulation without affecting those to i.v. bolus injections of exogenous α-CGRP (0.1, 0.18, 0.31, 0.56 and 1 μg/kg). This inhibition by CP-93,129 was abolished by the antagonists GR127935 (5-HT1B/1D) or SB224289 (5-HT1B), but not by BRL15572 (5-HT1D). The above results suggest that CP-93,129-induced inhibition of the vasodepressor (perivascular) sensory outflow in pithed rats is mainly mediated by activation of prejunctional 5-HT1B receptors. © 2010 Elsevier B.V.

Ammons D.R.,University of Texas–Pan American | Reyna A.,University of Texas–Pan American | Granados J.C.,University of Texas–Pan American | Ventura-Suarez A.,Escuela Nacional de Ciencias Biologicas del I.P.N. | And 3 more authors.
Applied and Environmental Microbiology | Year: 2013

Mutation of a novel cry-like gene (cry256) from Bacillus thuringiensis resulted in a protein crystal, normally located within the spore's exosporium, being found predominately outside the exosporium. The cry256 gene codes for a 3-domain Cry-like protein that does not correspond to any of the known Cry protein holotypes. © 2013, American Society for Microbiology.

Ayala-Mata F.,Escuela Nacional de Ciencias Biologicas del IPN | Barrera-Mendoza C.,Escuela Nacional de Ciencias Biologicas del IPN | Jimenez-Vazquez H.A.,Escuela Nacional de Ciencias Biologicas del IPN | Vargas-Diaz E.,Escuela Nacional de Ciencias Biologicas del IPN | Zepeda L.G.,Escuela Nacional de Ciencias Biologicas del IPN
Molecules | Year: 2012

The Weinreb amides 2a,b were prepared from the a,a-dimethoxyacetic acids 1c,d. A number of representative nucleophilic additions (RMgX and RLi) on 2 afforded a-ketoacetals 3a-j in 70-99% yield. These compounds represent a versatile arrangement of functional groups of significant synthetic value, as demonstrated in the synthesis of (±)-salbutamol. © 2012 by the authors.

Chavez-Cabrera C.,CINVESTAV | Flores-Bustamante Z.R.,CINVESTAV | Marsch R.,CINVESTAV | Montes M.D.C.,CINVESTAV | And 3 more authors.
Applied Microbiology and Biotechnology | Year: 2010

ATP-citrate lyase (ACL) is the key cytoplasmic enzyme which supplies acetyl-CoA for fatty acids in oleaginous yeast. Although it has been suggested that fatty acid and carotenoid biosynthesis may have a common source of acetyl-CoA in Phaffia rhodozyma, the source for carotenoids is currently unknown. The purpose of this work was to analyze the development of ACL activity during batch cultures of P. rhodozyma under ammonium-limited and nonammonium-limited conditions and study its possible relationship with carotenoid synthesis. Every experiment showed carotenoid accumulation linked to an increasing ACL activity. Moreover, the ACL activity increased with dissolved oxygen (DO), i.e., ACL responded to DO in a similar way as carotenoid synthesis. Additionally, in the ammonium-limited culture, ACL activity increased upon ammonium depletion. However, the contribution to carotenoid accumulation in that case was negligible. This suggests that P. rhodozyma has developed two components of ACL, each one responsive to a different environmental stimulus, i.e., DO and ammonium depletion. The role of each component is still unknown; however, considering that the former responds to DO and the known role of carotenoids as antioxidants, it may be a provider of acetyl-CoA for carotenoid synthesis. © 2009 Springer-Verlag.

Arias-Penaranda M.T.,CINVESTAV | Cristiani-Urbina E.,Escuela Nacional de Ciencias Biologicas del I.P.N. | Montes-Horcasitas C.,CINVESTAV | Esparza-Garciia F.,CINVESTAV | And 2 more authors.
Bioresource Technology | Year: 2013

The potential of microalgal oil from Scenedesmus incrassatulus as a feedstock for biodiesel production was studied. Cell concentration of S. incrassatulus and lipid content obtained during mixotrophic growth were 1.8g/L and 19.5±1.5% dry cell weight, respectively. The major components of biodiesel obtained from S. incrassatulus oil were methyl palmitate (26%) and methyl linoleate (49%), which provided a strong indication of high quality biodiesel. Fuel properties were determined by empirical equations and found to be within the limits of biodiesel standard ASTM D6751 and EN 14214. The quality properties of the biodiesel were high cetane number (62), low density (803kg/m3), low viscosity (3.78mm2/s), oxidation stability (9h) and cold filter plugging point (-4°C). Hence, S. incrassatulus has potential as a feedstock for the production of excellent quality biodiesel. © 2013 Elsevier Ltd.

Tibhe G.D.,Autonomous University of the State of Morelos | Lagunas-Rivera S.,Autonomous University of the State of Morelos | Vargas-Diaz E.,Escuela Nacional de Ciencias Biologicas Del IPN | Garcia-Barradas O.,University of Veracruz | Ordonez M.,Autonomous University of the State of Morelos
European Journal of Organic Chemistry | Year: 2010

Uncatalyzed one-pot, three-component reactions of aldehydes, chiral α-methylamines, and dimethyl phosphite under solvent-free conditions were used for the diastereoselective synthesis of α-amino phosphonates. The reactions proceeded with extremely high efficiency under mild conditions and gave good yields and diastereoselectivities (70:30 to 93:7 dr). This approach could be useful for the large-scale synthesis of several α-amino phosphonates. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vigueras-Cortes J.M.,Centro Interdisciplinario Of Investigacion Para El Desarrollo Integral Regional | Villanueva-Fierro I.,Centro Interdisciplinario Of Investigacion Para El Desarrollo Integral Regional | Garzon-Zuniga M.A.,Mexican Institute of Water Technology | De Jesus Navar-Chaidez J.,Centro Interdisciplinario Of Investigacion Para El Desarrollo Integral Regional | And 2 more authors.
Water Science and Technology | Year: 2013

Agave plants grow in semi-arid regions and are used for mescal production. However, agave fiber by-products are considered waste materials. Thus, we tested agave fiber as a filter media and biofilm material carrier for removing pollutants from municipal wastewater. Three laboratory-scale biofiltration reactors were used in two trials with five hydraulic loading rates (HLRs = 0.27, 0.54, 0.80, 1.07 and 1.34 m3 m-2 d-1). One series was conducted using mechanical aeration (0.62 m3 m -2 h-1). To prevent compaction, decreasing pressure and clogging of the filter media, 4, 8 and 12 internal divisions were evaluated in the biofilter column. After 17 months of continuous operation at an HLR of 0.80 m3 m-2 d-1, the removal efficiencies of the aerated biofilters were 92.0% biochemical oxygen demand, 79.7% chemical oxygen demand, 98.0% helminth eggs, 99.9% fecal coliforms and 91.9% total suspended solids. Statistical analysis showed that the chosen operational parameters significantly influenced the removal efficiencies of the biofilters. The effluent quality obtained under these conditions complied with the Mexican and US EPA standards for agricultural irrigation and green spaces, except for coliforms, which is why the effluents must be disinfected. Thus, agave fiber is a favorable choice for use as a packing material in biofiltration processes. © IWA Publishing 2013.

Osorio-Revilla G.,Escuela Nacional de Ciencias Biologicas del IPN | Gallardo-Velazquez T.,Escuela Nacional de Ciencias Biologicas del IPN | Ramirez-Torres A.,Escuela Nacional de Ciencias Biologicas del IPN | Rivera-Espinoza Y.,Escuela Nacional de Ciencias Biologicas del IPN
Canadian Journal of Chemical Engineering | Year: 2012

Residence time distributions (RTD) for aqueous maltodextrin solutions were determined in two kinds of spouted bed dryers: (1) conventional spouted bed (CSB) 0.305m diameter with a bed of polypropylene beads and (2) spout-fluid bed 0.143m diameter with draft tube submerged in a bed of FEP® pellets (S-FBDT). RTD, mean residence time t m, and spread of the distribution σ 2, were determined at different drying temperatures, spouting velocities, bed depths, spraying pressures, and feed concentrations. Average values of t m and σ 2 were 6.5min and 26.6min 2 for the CSB and 6.9min and 36min 2 for the S-FBDT, respectively, for all operating conditions except spraying pressure. RTD curves were well represented by the response of an ideal stirred tank with a superimposed bypass of 15% on average for the CSB and 7% on average for the S-FBDT dryer for all operating conditions. Increase in spraying pressure produced a reduction of t m and an increase in the bypass fraction of the product in both dryers. © 2011 Canadian Society for Chemical Engineering.

PubMed | National Polytechnic Institute of Mexico and Escuela Nacional de Ciencias Biologicas del IPN
Type: Journal Article | Journal: The journal of physical chemistry. A | Year: 2015

Captodative olefins are highly reactive and selective substrates in Diels-Alder and 1,3-dipolar cycloadditions. Seeking an explanation of this fact based on molecular energetics, the thermochemical analysis of 1-acetyl vinyl p-nitrobenzoate, a captodative olefin, has been performed using semi-micro-combustion calorimetry, effusion measurements through a quartz crystal microbalance, and differential scanning calorimetry. The molar standard combustion energy and enthalpy as well as the molar standard formation enthalpy are reported along with sublimation and melting enthalpies. From these data, experimental formation enthalpy of the gas-phase is derived and compared with the theoretical value calculated through the density functional theory procedure. The olefinic bond enthalpy is also computed from experimental data, and the relevance of the results is discussed.

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