Determinación de las condiciones de uso del almidón modificado en el mejoramiento de formulas alimenticias

The use of thickeners in the food industry is increasing constantly, because of the challenge to provide cheaper alternatives to the consumer of finished products, as well as comply with local regulations. However, in Ecuador, the supply of thickening is not very diverse, because the marketing is managed by houses which don’t have the necessary resources or trained personnel to improve and adapt their applications to local needs. Typically, thickeners used are: carboxymethyl cellulose (CMC), xanthan gum and guar gum, whose applications in cost-dose expensive the final product. On this basis, I propose as an alternative low-cost use of modified starches. One of the limitations in the use of modified starches is that the applications suggested by the manufacturer, this is, pH, temperature and addition of water, often do not provide the desired results in the final product because the process conditions and as, the raw materials used differ from those that are marketed locally. That is as, this report seeks to determine the suitable conditions of its implementation through the development of new formulations and / or partial or total replacement of existing formulas. For this purpose, experimental tests were done in semi-preserves: Tomato Sauce ketchup, canned fish such as sardines in tomato sauce and Albacora in cassava –onions sauce, as well as bakery products such as bread mold type. The results can be evidenced in the development of modified starch sheet and manufactured products are marketed in the local market.e

Bacillus subtilis remains translationally active after CRISPRi-mediated replication initiation arrest

ABSTRACTInitiation of bacterial DNA replication takes place at the origin of replication (oriC), a region characterized by the presence of multiple DnaA boxes that serve as the binding sites for the master initiator protein DnaA. This process is tightly controlled by modulation of the availability or activity of DnaA and oriC during development or stress conditions. Here, we aimed to uncover the physiological and molecular consequences of stopping replication in the model bacterium Bacillus subtilis. We successfully arrested replication in B. subtilis by employing a clustered regularly interspaced short palindromic repeats interference (CRISPRi) approach to specifically target the key DnaA boxes 6 and 7, preventing DnaA binding to oriC. In this way, other functions of DnaA, such as a transcriptional regulator, were not significantly affected. When replication initiation was halted by this specific artificial and early blockage, we observed that non-replicating cells continued translation and cell growth, and the initial replication arrest did not induce global stress conditions such as the SOS response.IMPORTANCEAlthough bacteria constantly replicate under laboratory conditions, natural environments expose them to various stresses such as lack of nutrients, high salinity, and pH changes, which can trigger non-replicating states. These states can enable bacteria to (i) become tolerant to antibiotics (persisters), (ii) remain inactive in specific niches for an extended period (dormancy), and (iii) adjust to hostile environments. Non-replicating states have also been studied because of the possibility of repurposing energy for the production of additional metabolites or proteins. Using clustered regularly interspaced short palindromic repeats interference (CRISPRi) targeting bacterial replication initiation sequences, we were able to successfully control replication initiation in Bacillus subtilis. This precise approach makes it possible to study non-replicating phenotypes, contributing to a better understanding of bacterial adaptive strategies

Medios de comunicación: entre la libertad de expresión y los grupos de poder. Programa Diálogos del Pensamiento 161

Particularmente en nuestro país, la construcción de la agenda mediática -es decir, la definición de los temas que predominarán en los medios de comunicación-, suele depender mucho de eventos coyunturales, pero sobre todo, está supeditada a intereses de diversa índole que van desde lo político, a lo económico-empresarial, e incluso la violencia, que también influye a la hora de informar. En medio de un marasmo informativo que busca saturarnos con la repetición de mensajes políticos, que decide sobre qué es lo que debemos conocer y qué no, que otorga pocos o nulos espacios a actores y opiniones nuevos, resulta vital la reflexión sobre la calidad de la información que producen los medios de comunicación, así como conocer cuáles son los intereses detrás de las grandes agencias de noticias y de los grandes emporios que monopolizan por igual canales de televisión, radio o medios electrónicos. A esta labor nos abocamos en compañía de Rosalía Orozco, Salvador Leetoy y Rodrigo Cornejo, todos especialistas en el tema. ¿Los medios hoy se debaten entre formar e informar o simplemente entretener? ¿Cuál es el papel de las audiencias, ser sólo receptoras pasivas de contenidos? ¿Cuáles son las implicaciones de una falta de regulación o autorregulación efectiva en los medios de comunicación? ¿Qué papel juegan las nuevas tecnologías en la construcción de las agendas mediáticas

GABA Production by Human Intestinal Bacteroides spp.: Prevalence, Regulation, and Role in Acid Stress Tolerance

The high neuroactive potential of metabolites produced by gut microbes has gained traction over the last few years, with metagenomic-based studies suggesting an important role of microbiota-derived γ-aminobutyric acid (GABA) in modulating mental health. Emerging evidence has revealed the presence of the glutamate decarboxylase (GAD)-encoding gene, a key enzyme to produce GABA, in the prominent human intestinal genus Bacteroides. Here, we investigated GABA production by Bacteroides in culture and metabolic assays combined with comparative genomics and phylogenetics. A total of 961 Bacteroides genomes were analyzed in silico and 17 metabolically and genetically diverse human intestinal isolates representing 11 species were screened in vitro. Using the model organism Bacteroides thetaiotaomicron DSM 2079, we determined GABA production kinetics, its impact on milieu pH, and we assessed its role in mitigating acid-induced cellular damage. We showed that the GAD-system consists of at least four highly conserved genes encoding a GAD, a glutaminase, a glutamate/GABA antiporter, and a potassium channel. We demonstrated a high prevalence of the GAD-system among Bacteroides with 90% of all Bacteroides genomes (96% in human gut isolates only) harboring all genes of the GAD-system and 16 intestinal Bacteroides strains producing GABA in vitro (ranging from 0.09 to 60.84 mM). We identified glutamate and glutamine as precursors of GABA production, showed that the production is regulated by pH, and that the GAD-system acts as a protective mechanism against acid stress in Bacteroides, mitigating cell death and preserving metabolic activity. Our data also indicate that the GAD-system might represent the only amino acid-dependent acid tolerance system in Bacteroides. Altogether, our results suggest an important contribution of Bacteroides in the regulation of the GABAergic system in the human gut

Trayectoria, aporte y transformación de la UdeG. Programa Diálogos del Pensamiento 67

La Universidad de Guadalajara atraviesa justamente en estos momentos el proceso electoral que lo llevará a elegir a su Rector General número 49, que ocupará el máximo puesto de la casa de estudios de Jalisco, durante el periodo 2013-2019. Ante este hecho, hemos decidido realizar una díada especial en torno a los aspectos sustantivos que definen la personalidad actual de nuestra Universidad, desarrollando su Historia, para conocer la trayectoria que la proyecta hacia el futuro y poder comprender la función e impacto que ha tenido en el occidente de nuestro país, desde su fundación colonial y hasta la reforma académica que la llevó a convertirse en una Red Universitaria extendida sobre la casi totalidad del estado de Jalisco. Para cumplir con este propósito, nuestros conductores, Gabriela Díaz y Ramón Gómez, departen con Alfredo Mendoza Cornejo, especializado en historiar la Universidad de Guadalajara y quien además fuera el primer rector del Centro Universitario de la Ciénega (1994-1998), por lo que conoce como pocos, la historia de nuestra alma mater. Esta emisión aborda, pues, el sentido y los orígenes de una institución que ha afectado de manera significativa la vida del occidente del país, y de la que todos hemos sido beneficiarios

Potential role of sodium-proton exchangers in the low concentration arsenic trioxide-increased intracellular pH and cell proliferation.

Arsenic main inorganic compound is arsenic trioxide (ATO) presented in solution mainly as arsenite. ATO increases intracellular pH (pHi), cell proliferation and tumor growth. Sodium-proton exchangers (NHEs) modulate the pHi, with NHE1 playing significant roles. Whether ATO-increased cell proliferation results from altered NHEs expression and activity is unknown. We hypothesize that ATO increases cell proliferation by altering pHi due to increased NHEs-like transport activity. Madin-Darby canine kidney (MDCK) cells grown in 5 mmol/L D-glucose-containing DMEM were exposed to ATO (0.05, 0.5 or 5 µmol/L, 0-48 hours) in the absence or presence of 5-N,N-hexamethylene amiloride (HMA, 5-100 µmol/L, NHEs inhibitor), PD-98059 (30 µmol/L, MAPK1/2 inhibitor), Gö6976 (10 µmol/L, PKCα, βI and μ inhibitor), or Schering 28080 (10 µmol/L, H(+)/K(+)ATPase inhibitor) plus concanamycin (0.1 µmol/L, V type ATPases inhibitor). Incorporation of [(3)H]thymidine was used to estimate cell proliferation, and counting cells with a hemocytometer to determine the cell number. The pHi was measured by fluorometry in 2,7-bicarboxyethyl-5,6-carboxyfluorescein loaded cells. The Na(+)-dependent HMA-sensitive NHEs-like mediated proton transport kinetics, NHE1 protein abundance in the total, cytoplasm and plasma membrane protein fractions, and phosphorylated and total p42/44 mitogen-activated protein kinases (p42/44(mapk)) were also determined. Lowest ATO (0.05 µmol/L, ~0.01 ppm) used in this study increased cell proliferation, pHi, NHEs-like transport and plasma membrane NHE1 protein abundance, effects blocked by HMA, PD-98059 or Gö6976. Cell-buffering capacity did not change by ATO. The results show that a low ATO concentration increases MDCK cells proliferation by NHEs (probably NHE1)-like transport dependent-increased pHi requiring p42/44(mapk) and PKCα, βI and/or μ activity. This finding could be crucial in diseases where uncontrolled cell growth occurs, such as tumor growth, and in circumstances where ATO, likely arsenite, is available at the drinking-water at these levels

GABA Production by Human Intestinal Bacteroides spp.: Prevalence, Regulation, and Role in Acid Stress Tolerance

The high neuroactive potential of metabolites produced by gut microbes has gained traction over the last few years, with metagenomic-based studies suggesting an important role of microbiota-derived γ-aminobutyric acid (GABA) in modulating mental health. Emerging evidence has revealed the presence of the glutamate decarboxylase (GAD)-encoding gene, a key enzyme to produce GABA, in the prominent human intestinal genus Bacteroides. Here, we investigated GABA production by Bacteroides in culture and metabolic assays combined with comparative genomics and phylogenetics. A total of 961 Bacteroides genomes were analyzed in silico and 17 metabolically and genetically diverse human intestinal isolates representing 11 species were screened in vitro. Using the model organism Bacteroides thetaiotaomicron DSM 2079, we determined GABA production kinetics, its impact on milieu pH, and we assessed its role in mitigating acid-induced cellular damage. We showed that the GAD-system consists of at least four highly conserved genes encoding a GAD, a glutaminase, a glutamate/GABA antiporter, and a potassium channel. We demonstrated a high prevalence of the GAD-system among Bacteroides with 90% of all Bacteroides genomes (96% in human gut isolates only) harboring all genes of the GAD-system and 16 intestinal Bacteroides strains producing GABA in vitro (ranging from 0.09 to 60.84 mM). We identified glutamate and glutamine as precursors of GABA production, showed that the production is regulated by pH, and that the GAD-system acts as a protective mechanism against acid stress in Bacteroides, mitigating cell death and preserving metabolic activity. Our data also indicate that the GAD-system might represent the only amino acid-dependent acid tolerance system in Bacteroides. Altogether, our results suggest an important contribution of Bacteroides in the regulation of the GABAergic system in the human gut

Soft-metal(loid)s induce protein aggregation in Escherichia coli

Metal(loid) salts were used to treat infectious diseases in the past due to their exceptional biocidal properties at low concentrations. However, the mechanism of their toxicity has yet to be fully elucidated. The production of reactive oxygen species (ROS) has been linked to the toxicity of soft metal(loid)s such as Ag(I), Au(III), As(III), Cd(II), Hg(II), and Te(IV). Nevertheless, few reports have described the direct, or ROS-independent, effects of some of these soft-metal(loid)s on bacteria, including the dismantling of iron-sulfur clusters [4Fe-4S] and the accumulation of porphyrin IX. Here, we used genome-wide genetic, proteomic, and biochemical approaches under anaerobic conditions to evaluate the direct mechanisms of toxicity of these metal(loid)s in Escherichia coli. We found that certain soft-metal(loid)s promote protein aggregation in a ROS-independent manner. This aggregation occurs during translation in the presence of Ag(I), Au(III), Hg(II), or Te(IV) and post-translationally in cells exposed to Cd(II) or As(III). We determined that aggregated proteins were involved in several essential biological processes that could lead to cell death. For instance, several enzymes involved in amino acid biosynthesis were aggregated after soft-metal(loid) exposure, disrupting intracellular amino acid concentration. We also propose a possible mechanism to explain how soft-metal(loid)s act as proteotoxic agents.ISSN:1664-302

Culturas y política cultural en el DMQ : una colección de ensayos

Los ensayos que integran esta compilación, nacen de una suma de esfuerzos que aunque colectivos parten desde múltiples perspectivas, visiones y construcciones de lo cultural en la ciudad. Su intención, que constituye su denominador común, es contribuir a la interpretación del momento histórico y a la definición consecuente de prácticas y políticas culturales que demanda la actual coyuntura del país, en general, y del Distrito Metropolitano de Quito, en particular. Por su complejidad y heterogeneidad se debe reconocer que este ejercicio debe contar con la activa participación del Estado en sus distintos niveles de gobierno y con sus diferentes institucionalidades; pero también con la de entidades privadas, de la sociedad civil y sus organizaciones y grupos comunitarios. Será como resultado de este amplio, serio y propositivo diálogo que la ciudadanía podrá dar continuidad, sin duda, a la ruptura y al cambio cultural histórico que la sociedad ecuatoriana está viviendo

Effect of ATO on ^HMA−s<i>J</i>_H⁺ kinetics.

<p>Transmembrane H⁺ flux rates sensitive to inhibition by 5-N,N-hexamethylene amiloride (HMA, 5 µmol/L) (^HMA−s<i>J</i>_H⁺) in MDCK cells cultured for 48 hours without (○) or with (•) 0.05 µmol/L arsenic trioxide (ATO) dissolved in water in the presence of increasing extracellular concentrations of sodium (Na⁺). The data was adjusted to a Michaelis-Menten hyperbola showing an increase in a lineal component for the range of Na⁺ used in the experiments (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051451#s2" target="_blank">Methods</a>). (b) Eadie-Hofstee plot of data in (a). (c) Saturable ^HMA−s<i>J</i>_H⁺ in cells as in (a) where the data was adjusted to a single Michaelis-Menten hyperbola (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051451#s2" target="_blank">Methods</a>). (d) Eadie-Hofstee plot of data in (c). Mean±S.E.M. (n = 14).</p