Metabolic Flux Distribution and Thermodynamic Analysis of Green Fluorescent Protein Production in Recombinant Escherichia coli: The Effect of Carbon Source and CO2 Partial Pressure

R. Axayácatl González-García,E. Ines Garcia-Peña,Edgar Salgado-Manjarrez,Juan S. Aranda-Barradas 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.6

Increasing recombinant protein production yieldsfrom bacterial cultures remains an important challenge inbiotechnology. Acetate accumulation due to high dissolvedcarbon dioxide (pCO2) concentrations in the medium hasbeen identified as a factor that negatively affects suchyields. Under appropriate culture conditions, acetate couldbe re-assimilated by bacterial cells to maintain heterologousproteins production. In this work, we developed a simplifiedmetabolic network aiming to establish a reaction rate analysisfor a recombinant Escherichia coli when producing greenfluorescent protein (GFP) under controlled pCO2 concentrations. Because E. coli is able to consume both glucoseand acetate, the analysis was performed in two stages. Ourresults indicated that GFP synthesis is an independentprocess of cellular growth in some culture phases. Additionally,recombinant protein production is influenced bythe available carbon source and the amount of pCO2 in theculture medium. When growing on glucose, the increase inthe pCO2 concentration produced a down-regulation ofcentral carbon metabolism by directing the carbon fluxtoward acetate accumulation; as a result, cellular growthand the overall GFP yield decreased. However, the maximumspecific rate of GFP synthesis occurred with acetate as themain available carbon source, despite the low activity inthe other metabolic pathways. To maintain cellular functions,including GFP synthesis, carbon flux was re-distributedtoward the tricarboxylic acid cycle and the pentose phosphatepathway to produce ATP and NADH. The thermodynamicanalysis allowed demonstrating the feasibility of the simplifiednetwork for describing the metabolic state of a recombinantsystem.

Protective Effects of Sea Spaghetti-Enriched Restructured Pork Against Dietary Cholesterol: Effects on Arylesterase and Lipoprotein Profile and Composition of Growing Rats

Adriana R. Schultz Moreira,Raúl Olivero-David,Miguel Vázquez-Velasco,Laura González-Torres,Juana Benedí,Sara Bastida,Francisco J. Sánchez-Muniz 한국식품영양과학회 2014 Journal of medicinal food Vol.17 No.8

There is a general assumption that seaweeds are hypocholesterolemics and antioxidants. However, controversial results suggest specific properties for each individual alga. This study aims to assess the effect of including Sea Spaghetti alga (S) in a restructured-pork (RP) diet, both enriched and not enriched with dietary cholesterol, on arylesterase (AE) activity and lipoprotein concentration and composition of Wistar rats. Four groups of 10 growing male Wistar rats were each fed a mix of 85% AIN-93M diet and 15% freeze-dried RP for 5 weeks. The control group (C) consumed control RP-C; the S group consumed RP-S with 5% seaweeds; the Chol-C group consumed the C diet but enriched with cholesterol (2.43%) and cholic acid (0.49%); the Chol-S group consumed the S diet but enriched with cholesterol and cholic acid. AE activity was five times higher (P < .01) in S compared with C rats, but three times lower in Chol-S compared with Chol-C rats (P < .01). The Chol-C diet induced hypercholesterolemia but reduced triglycerides (TG), giving rise to the presence of very low-density lipoprotein (VLDL) that was enriched in cholesterol. The Chol-S diet partially blocked (P < .001) the hypercholesterolemic induction of the Chol-C diet, and reduced TG levels (P < .05) with respect to S rats. The cholesterol supplementation increased total cholesterol, VLDL-cholesterol, and intermediate-density lipoprotein + LDL-cholesterol (IDL + LDL)-cholesterol (P < .001) in Chol-C rats, but the effect was lower in the Chol-S diet. In conclusion, RP-S increases the antioxidant capacity within a noncholesterol enriched diet while improving the lipoprotein profile within a cholesterol-enriched diet.

Fertilizing capacity of cryopreserved sperm of Chirostoma jordani (Woolman, 1894)

Bustamante-González Jesús Dámaso,Gutiérrez-Díaz Dulce Leticia,Baca-Alejo Judith Sarai,Figueroa-Lucero Gerardo,Arenas-Ríos Edith,Hernández-Rubio María Cecilia,Ávalos-Rodríguez Alejandro 한국수산과학회 2024 Fisheries and Aquatic Sciences Vol.27 No.5

The genus Chirostoma is endemic from the Mesa Central of Mexico. It is conformed of 18 species and six subspecies. Five species are in some category of risk, because of this, Chirostoma jordani is an excellent model species to implement biotechnologies like gametes cryopreservation. Aim of present study was to evaluate fertilizing capacity of cryopreserved C. jordani sperm, as alternative to conservation and assisted reproduction in this specie and genus. Males and females were collected from wild Atlangatepec dam stock, Tlaxcala State, Mexico. Seminal quality was evaluated in fresh and cryopreserved semen with three cryoprotective agents (CPAs): 10% dimethyl sulfoxide (DMSO), 10% methanol (MeOH), 14% ethylene glycol (EG) and it was determined its post-thaw fertilizing capacity. Sperm motility percentage decreased during cryopreservation process (p < 0.05). There were not significant differences in post-thaw motility percentage between EG (53.5 ± 1.9%) and MeOH (53.3 ± 1.3%), but DMSO (50.3 ± 0.5%) was significantly different (p < 0.05). Results showed that 0.2 μL fresh semen were enough to fertilize 100% oocytes (n = 60). 10 μL DMSO and 5 μL MeOH and EG cryopreserved semen were necessary to fertilize oocytes 100% (n = 60) (p < 0.05). Cryopreservation and fertilization protocol for C. jordani sperm was efficient and it could be used for its assisted reproduction.

Effect of the In₂O₃ content on the photodegradation of the alizarin dye using TiO₂-In₂O₃ nanostructured semiconductors

V. Rodríguez-González,F. Paraguay-Delgado,X. García-Montelongo,L.M. Torres-Martínez,R. Gómez 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6

The photocatalytic degradation of the synthetic red mordant dye alizarin on TiO2-In2O3 semiconductors as a function of the In2O3 content (1-12 wt%) was studied. High specific surface areas varying from 122 to 178 m2 g−1, depending on the In2O3 content, were obtained. A modification of the Eg band gap from 3.12 to 3.50 eV was obtained for low and high In2O3 contents. The XRD spectral patterns of the solids showed that anatase is the main crystalline titania phase. STEM-EDX chemical maps show that the In2O3 was found highly dispersed on the surface of the TiO2-In2O3 mixed oxide. By means of TEM images, nanostructured materials with crystallite sizes between 8 and 12 nm were identified. The photocatalytic activity for the alizarin degradation showed a maximum with the catalyst with 3.0 wt% of In2O3. The role of the In2O3 developing an optimal alizarin adsorption on the TiO2-In2O3 semiconductors is discussed. The photocatalytic degradation of the synthetic red mordant dye alizarin on TiO2-In2O3 semiconductors as a function of the In2O3 content (1-12 wt%) was studied. High specific surface areas varying from 122 to 178 m2 g−1, depending on the In2O3 content, were obtained. A modification of the Eg band gap from 3.12 to 3.50 eV was obtained for low and high In2O3 contents. The XRD spectral patterns of the solids showed that anatase is the main crystalline titania phase. STEM-EDX chemical maps show that the In2O3 was found highly dispersed on the surface of the TiO2-In2O3 mixed oxide. By means of TEM images, nanostructured materials with crystallite sizes between 8 and 12 nm were identified. The photocatalytic activity for the alizarin degradation showed a maximum with the catalyst with 3.0 wt% of In2O3. The role of the In2O3 developing an optimal alizarin adsorption on the TiO2-In2O3 semiconductors is discussed.

Relationship among blood indicators of lipomobilization and hepatic function during early lactation in high-yielding dairy cows

Felix Diaz González,Rodrigo Muiño,Víctor Pereira,Rómulo Campos,José Luis Benedito 대한수의학회 2011 Journal of Veterinary Science Vol.12 No.3

Blood indicators are used as a tool to diagnose metabolic disorders. The present work was conducted to study the relationships among blood indicators of lipomobilization and hepatic function in high-yielding dairy cows. Two groups of Holstein cows were studied: 27 early lactation cows and 14 mid lactation cows from four different herds with similar husbandry characteristics in Galicia, Spain. Blood samples were obtained to measure beta-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), triglycerides (TG), and the activity of aspartate transaminase (AST) and gamma-glutamyl transferase. Cows in early lactation had higher levels of BHB and NEFA than mid lactation cows. High lipomobilization (NEFA > 400 μmol/L) was detected in 67% and 7% of early lactation and mid lactation cows, respectively, while subclinical ketosis (BHB > 1.2 mmol/L) was detected in 41% and 28% of the early lactation and lactation cows, respectively. TG concentrations were low in all cows suffering subclinical ketosis and in 61% of the cows with high lipomobilization. During early lactation, 30% of cows suffered hepatic lipidosis as detected by levels of AST. Compromised hepatic function was observed in early lactation cows as shown by lower concentrations of glucose, total protein, and urea.

Corrosion activity and solubility in polar oils of three bis (trifluoromethylsulfonyl) imide/bis(trifluoromethylsulfonyl) amide ([NTF2]) anion-based ionic liquids

A. Fernández-González,M.T. Mallada,J.L. Viesca,R. González,R. Badía,A. Hernández-Battez 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.56 No.-

The corrosion behaviour and solubility of three bis(trifluoromethylsulfonyl)amide1 ([NTf2]) anion-basedionic liquids: 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([C12MIM][NTf2]),tributylmethylammonium bis(trifluoromethylsulfonyl)amide ([N4441][NTf2]), and methyltrioctylammo-nium bis(trifluoromethylsulfonyl)amide ([N1888][NTf2]), as a component in a mixture with different baseoils were analysed. Six polar oils suitable for use in lubrication were utilized as base oil. Solubility testswere performed by using turbidimetry, and corrosion was checked at 4 v/v% by examining the roughnessand chemical composition of the surface after 21 days. The results showed that long carbon chains in thecation improve the solubility greatly in diesters and slightly in polyolesters. Corrosion was not detected atthis concentration.

Silver nanoparticles incorporated into Na₂Ti6O13 microfibers

V. Rodríguez-González,I. Juárez-Ramírez,R. Zanella,M.E. Zarazúa,L.M. Torres-Martínez 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6

This research is concerned with novel semiconductor composites of sodium hexatitanate oxide (Na2Ti6O13), and silver metallic nanoparticles. The Na2Ti6O13 was prepared by two methods, a sol-gel process and a solid state reaction. The silver nanoparticles were incorporated into the titanate by a deposition-precipitation technique, using NaOH as precipitation agent in the dark. Ag/Na2Ti6O13 microfibers were obtained by the sol-gel method, meanwhile octagonal microbar agglomerates were the product of the solid state reaction. The SEM-TEM observations showed silver particles with a nanometric size (5-7 nm); and fibrillar structures in the sol-gel sodium titanates. The UV-Vis-RD spectroscopy showed a blue shift Eg from 3.3 to 3.4 nm; and a plasmon surface resonance in the visible region. These materials are proposed as potential photocatalysts for contaminated water purification. This research is concerned with novel semiconductor composites of sodium hexatitanate oxide (Na2Ti6O13), and silver metallic nanoparticles. The Na2Ti6O13 was prepared by two methods, a sol-gel process and a solid state reaction. The silver nanoparticles were incorporated into the titanate by a deposition-precipitation technique, using NaOH as precipitation agent in the dark. Ag/Na2Ti6O13 microfibers were obtained by the sol-gel method, meanwhile octagonal microbar agglomerates were the product of the solid state reaction. The SEM-TEM observations showed silver particles with a nanometric size (5-7 nm); and fibrillar structures in the sol-gel sodium titanates. The UV-Vis-RD spectroscopy showed a blue shift Eg from 3.3 to 3.4 nm; and a plasmon surface resonance in the visible region. These materials are proposed as potential photocatalysts for contaminated water purification.

Acute toxicity of aqueous extract of Ambrosia arborescens Mill. on biochemical and histopathological parameters in rats

Silva-Correa Carmen R.,Villarreal-La Torre Víctor E.,González-Siccha Anabel D.,Cruzado-Razco José L.,González-Blas María V.,Sagástegui-Guarniz William Antonio,Calderón-Peña Abhel A.,Aspajo-Villalaz Ci 한국독성학회 2022 Toxicological Research Vol.38 No.2

Medicinal plants play an important role in the management of various diseases, so their use has become widespread. However, in some cases the population uses plant species regardless of the toxicity they may possess. The objective of this study was to evaluate the acute toxicity of aqueous extract from the leaves of Ambrosia arborescens Mill. on the biochemical and histopathological parameters of albino Holtzman rats. To do this, the leaves of A. arborescens were collected in the province of Julcan, La Libertad Region—Peru. OECD (Organisation for Economic Cooperation and Development) guideline 423 was conducted, forming experimental groups of 10 animals each one (5 males and 5 females): Group I (Control), which received 2 mL physiological saline solution (SSF 0.9%), Groups II and III (A. arborescens-300 and A. arborescens-2000), which were given the aqueous extract leaves of A. arborescens in a single dose of 300 and 2000 mg/kg/day, respectively. On the 14th day of exposure, biochemical (creatinine, ALT and AST) and histopathological parameters were measured. The results show that the aqueous extract of A. arborescens at the dose of 2000 mg/kg produces an increase in biochemical parameters which is related to histopathological analysis of liver and renal tissue with mild congestion. The study concludes that the aqueous extract leaves of A. arborescens has a LD50 greater than 2000 mg/kg and produces mild congestion in kidneys and liver, but showed no significant toxicological changes in the other albino Holtzman rats organs.

Heat Treated Twin Wire Arc Spray AISI 420 Coatings Under Dry and Wet Abrasive Wear

E. Rodriguez,M. A. González,H. R. Monjardín,O. Jimenez,M. Flores,J. Ibarra 대한금속·재료학회 2017 METALS AND MATERIALS International Vol.23 No.6

The influence of applying two different heat treatments such as: deep cryogenic and tempering on dry/wetabrasive wear resistance of twin wire arc spray martensitic AISI 420 coatings was evaluated by using a modifiedrubber wheel type test apparatus. A load dependency was observed on the abrasive wear rate behavior ofboth; dry and wet tests. Three body (rolling) and two body (sliding) wear mechanisms were identified in dryconditions, prevailing rolling at lower and higher loads. However, at higher loads, more presence of groovingand pits formation was observed. Coatings tempered at 205 °C/1 h displayed better wear resistance thancryogenic treated ones. A change in wear mechanism between dry and wet conditions was observed; two bodywear mechanism predominated respect to three body. In both; dry and wet conditions the microstructure(several inter-splat oxides) as well as strain and residual stress promotes brittle material removal which wasmore evident in cryogenic and as-sprayed samples during dry test and at higher loads in wet conditions.

Pd supported catalyst for gas-phase 1,2-dichloroethane abatement: Efficiency and high selectivity towards oxygenated products

Zouhair Boukha,Jonatan González-Prior,Beatriz de Rivas,Juan R. González-Velasco,Rubén López-Fonseca,José I. Gutiérrez-Ortiz 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-

Hydroxyapatite (HAP) support has been synthesised and impregnated with different amounts of Pd. Theprepared Pd/HAP catalysts have been thoroughly characterised by BET, XRD, TEM, UV–visible–NIR, FTIR,XPS, CO2-TPD and NH3-TPD techniques and tested in the DCE oxidation reaction. The characterisation of the catalysts has revealed a clear evolution of the Pd species structure, byincreasing the Pd content, from highly dispersed tetrahedral coordinated Pd2+ to larger Pd2+ speciesparticles adopting square planar geometry. The latter seems to be partially encapsulated by the HAPsupport. In DCE oxidation reaction the Pd/HAP system has shown an activity comparable to that of conventionalsystem (Pd/alumina). However, the former has proved high selectivity towards the production ofoxygenated products (COx (CO2 and CO)). Notably, in contrast to Pd/alumina, the DCE oxidation does notyield vinyl chloride intermediate product over Pd/HAP. This catalytic behaviour has been related to themoderate acidity of HAP compared to that of alumina together with its interaction with the Pd activephase. This report, then, considers that Pd(x)/HAP could be presented as a good alternative to thosereported in the available literature.