The birth and early years of INA, the International Neurotoxicology Association

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Evaluation of in vitro neurotoxicity of methyl mercury, PCB153 and PCB126

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Ethanol Induces Cholesterol Efflux and Up-regulates ATP-binding Cassette Cholesterol Transporters in Fetal Astrocytes

Cholesterol plays an important role during brain development, since it is involved in glial cell proliferation, neuronal survival and differentiation, and synaptogenesis. Astrocytes produce large amounts of brain cholesterol and produce and release lipoproteins containing apoE that can extract cholesterol from CNS cells for elimination. We hypothesized that some of the deleterious effects of ethanol in the developing brain may be due to the disruption of cholesterol homeostasis in astrocytes. This study investigates the effect of ethanol on cholesterol efflux mediated by ATP-binding cassette (ABC) cholesterol transporters. In fetal rat astrocytes in culture, ethanol caused a concentration-dependent increase in cholesterol efflux and increased the levels of ABCA1 starting at 25 mm. Similar effects of ethanol on cholesterol efflux and ABCA1 were also observed in fetal human astrocytes. In addition, ABCA1 levels were increased in the brains of 7-day-old pups treated for 3 days with 2, 4, or 6 g/kg ethanol. Ethanol also increased apoE release from fetal rat astrocytes, and conditioned medium prepared from ethanol-treated astrocytes extracted more cholesterol than conditioned medium from untreated cells. In addition, ethanol increased the levels of another cholesterol transporter, ABCG1. Ethanol did not affect cholesterol synthesis and reduced the levels of intracellular cholesterol in rat astrocytes. Retinoic acid, which induces teratogenic effects similarly to ethanol, also caused up-regulation of ABCA1 and ABCG1

Ward identities for the Anderson impurity model: derivation via functional methods and the exact renormalization group

Using functional methods and the exact renormalization group we derive Ward identities for the Anderson impurity model. In particular, we present a non-perturbative proof of the Yamada-Yosida identities relating certain coefficients in the low-energy expansion of the self-energy to thermodynamic particle number and spin susceptibilities of the impurity. Our proof underlines the relation of the Yamada-Yosida identities to the U(1) x U(1) symmetry associated with particle number and spin conservation in a magnetic field.Comment: 8 pages, corrected statements about infintite flatband limi

Astrocytes protect against diazinon- and diazoxon-induced inhibition of neurite outgrowth by regulating neuronal glutathione

Evidence demonstrating that human exposure to various organophosphorus insecticides (OPs) is associated with neurobehavioral deficits in children continues to emerge. The present study focused on diazinon (DZ) and its active oxygen metabolite, diazoxon (DZO), and explored their ability to impair neurite outgrowth in rat primary hippocampal neurons as a mechanism of developmental neurotoxicity. Both DZ and DZO (0.5-10. μM) significantly inhibited neurite outgrowth in hippocampal neurons, at concentrations devoid of any cyototoxicity. These effects appeared to be mediated by oxidative stress, as they were prevented by antioxidants (melatonin, N-t-butyl-alpha-phenylnitrone, and glutathione ethyl ester). Inhibition of neurite outgrowth was observed at concentrations below those required to inhibit the catalytic activity of acetylcholinesterase. The presence of astrocytes in the culture was able to provide protection against inhibition of neurite outgrowth by DZ and DZO. Astrocytes increased neuronal glutathione (GSH) in neurons, to levels comparable to those of GSH ethyl ester. Astrocytes depleted of GSH by l-buthionine-(S,R)-sulfoximine no longer conferred protection against DZ- and DZO-induced inhibition of neurite outgrowth. The findings indicate that DZ and DZO inhibit neurite outgrowth in hippocampal neurons by mechanisms involving oxidative stress, and that these effects can be modulated by astrocytes and astrocyte-derived GSH. Oxidative stress from other chemical exposures, as well as genetic abnormalities that result in deficiencies in GSH synthesis and regulation, may render individuals more susceptible to these developmental neurotoxic effects of OPs. © 2014 Elsevier Ireland Ltd

Acidificación biológica de vinos de pH elevado mediante la utilización de bacterias lácticas

Actualmente, se están observando las consecuencias del cambio climático en la vitivinivultura. En los últimos años se están generando cosechas más tempranas y uvas con una descompensación entre la madurez fenólica y la madurez industrial. Estas uvas generan mostos con una elevada concentración de azúcares y una baja concentración de ácidos, que dan lugar a vinos con una alta concentración de etanol, una baja AT y un elevado pH. Los vinos de pH elevado presentan varios inconvenientes. Son vinos planos y sin frescor, tienen una elevada inestabilidad microbiológica y generan una disminución en la capacidad antiséptica del anhídrido sulfuroso. El pH de los vinos puede descenderse mediante metodologías de acidificación física, química y biológica. La ventaja de la utilización de métodos biológicos es que en la actualidad no están sujetos a regulación y además pueden utilizarse en la elaboración de vinos ecológicos. Varios autores ya han desarrollado estrategias para la acidificación biológica de vinos con levaduras, pero no han obtenido demasiado éxito. En este trabajo se ha planteado la alternativa de la utilización de bacterias lácticas (BL) para inducir acidificación biológica en vinos de pH elevado. Para ello, puede aprovecharse el metabolismo de las BL durante la vinificación para convertir los azúcares en ácido láctico mediante fermentación láctica (FL), y de este modo descender el pH del vino. Además de la producción de ácido láctico, el metabolismo de otros ácidos puede interferir en el pH del vino. Por un lado, la síntesis de ácido málico por las levaduras desciende el pH del vino, pero su degradación por las BL durante la fermentación maloláctica (FML) puede aumentarlo, aunque esta reacción resulta beneficiosa en la mayoría de los vinos ya que produce una mejora organoléptica y aumenta la estabilidad microbiológica. Por otro lado, la síntesis de ácido cítrico por parte de las levaduras desciende el pH del vino y su degradación por parte de algunas cepas de BL aumenta la estabilidad microbiológica, pero a su vez asciende el pH. De los cinco géneros de BL presentes durante la vinificación se planteó el género Lactobacillus como el candidato para inducir acidificación biológica en vinos porque presentan mejor crecimiento y metabolismo a pHs altos que otros géneros, algunas cepas son tolerantes al etanol, tienen elevada tolerancia al SO2, poseen una gran diversidad de enzimas capaces de producir compuestos aromáticos favorables, y además algunas cepas sintetizan plantaricinas que favorecen su implantación. Para ello en la presente tesis doctoral se plantearon los siguientes objetivos: la selección de cepas de Lactobacillus para inducir acidificación biológica en vinos, la optimización del proceso de acidificación biológica, la obtención de cultivos iniciadores y la evaluación de su comportamiento y la evaluación a nivel semiindustrial del proceso de acidificación biológica diseñado. Para llevar a cabo la selección de cepas se utilizaron cepas de diferentes especies del género Lactobacillus de la colección Enolab, que habían sido previamente aisladas de procesos de vinificación. La mayoría de los ensayos se realizaron en medio MC pH 3.5. El programa de selección se basó en un sistema de puntuaciones en base a criterios de primer orden y de segundo orden. Se consideraron criterios de primer orden un crecimiento superior a 70 unidades de área bajo la curva (ABC), que realizaran la FML, que descendieran más de 0.35 unidades el pH del medio y que sintetizaran más de 12 g/L de ácido láctico por FL. Las cepas que cumplieron cada uno de estos criterios se puntuaron con 10 puntos. Los criterios de segundo orden fueron la resistencia a la lisozima y al SO2, puntuándose con 5 puntos las cepas más resistentes a estos compuestos. Tras el sumatorio de puntos se seleccionaron las cepas con mayor puntuación : Enolab 4607 y Enolab 4608, ambas de la especie L. plantarum. Las cepas seleccionadas se caracterizaron en base a su metabolismo en medio MC y a la posible producción de aminas biógenas. Durante un cultivo de una semana en medio MC ambas cepas descendieron el pH del medio 0.73 unidades, consumieron entre 20 y 30 g/L de azúcares produciendo entre 12 y 12.5 g/L de ácido láctico por FL. Además, realizaron la FML y consumieron el 100% del ácido cítrico sin producir ácido acético. En cuanto a la producción de aminas biógenas, ambas cepas fueron incapaces de sintetizar histamina y putrescina. En cambio, ambas cepas poseían el gen que codifica para la tirosina descarboxilasa, aunque ambas cepas no sintetizaron tiramina o lo hicieron en bajas cantidades. Para optimizar el proceso de acidificación biológica se establecieron varios objetivos específicos: la determinación de la estrategia de inoculación de la BL durante la vinificación, la estimación de tiempo de acidificación, la elección de la levadura fermentativa a utilizar en el proceso y la evaluación de otros factores que pueden afectar al proceso de acidificación. Se estableció que para llevar a cabo el proceso de acidificación se debía inocular la BL en mosto de forma previa a la levadura. En estas condiciones la BL inoculada era capaz de crecer hasta el momento de inoculación de la levadura, sintetizando elevadas cantidades de ácido láctico, realizando la FML y descendiendo el pH del medio. Se estableció como un periodo adecuado entre la inoculación de la BL y la levadura fermentativa de entre 48 y 72 horas para llevar a cabo la acidificación deseada. Durante este periodo, la cepa Enolab 4608 produjo entre 8 y 10 g/L de ácido láctico, realizó la FML y descendió el pH del medio entre 0.2 y 0.3 unidades. La combinación levadura-bacteria que generó los mejores resultados en el proceso de vinificación con acidificación fue Enolab 4608 y Uvaferm VN®. Mediante esta combinación se obtuvo la mayor concentración de bacterias viables durante toda la vinificación, generándose los mayores niveles de ácido láctico y la mayor acidificación. También se evaluaron otros factores que pueden afectar al proceso de acidificación como el pH del mosto, la presencia de microbiota autóctona, los polifenoles y la adición de lisozima y SO2. Se determinó que la acidificación del vino final resultaba más efectiva cuanto más elevado era el pH del mosto inicial. También se observó que el comportamiento de las bacterias acidificantes se vio altamente influenciado por la presencia de microbiota autóctona. Los polifenoles también ejercieron una influencia negativa sobre el crecimiento y la capacidad acidificante y maloláctica de las bacterias. El tratamiento con lisozima y con SO2 también afectó al crecimiento y a la capacidad acidificante de las bacterias. El SO2 afectó en mayor medida a la viabilidad de las bacterias, no observándose acidificación en medios con concentraciones iguales o superiores a 0.1 mg/mL de este compuesto. El tercer objetivo fue la obtención de cultivos iniciadores de las cepas acidificantes seleccionadas para su inoculación directa en vinificaciones semiindustriales. Se seleccionó un proceso de producción de biomasa y liofilización para la obtención de cultivos iniciadores altamente efectivos. Además se comprobó que la rehidratación del cultivo iniciador en soluciones de NutrientVitEnd® y OptiMalo Plus® activaron de forma más eficaz el sistema metabólico bacteriano proporcionando un cultivo más activo en el momento de la inoculación. El cuarto objetivo del trabajo fue la evaluación a nivel semiindustrial del proceso de acidificación biológica diseñado. En las vinificaciones semiindustriales no se consiguió un grado de acidificación semejante al obtenido en el laboratorio, a pesar de que las BL inoculadas mantuvieron su viabilidad durante el proceso de acidificación y de que se implantaron frente a la microbiota autóctona. Tampoco consiguieron completar totalmente la FML. Ambas cosas indican que la actividad metabólica de las BL estaba inhibida. En cambio, si se observaron importantes modificaciones organolépticas en los vinos inoculados con estos cultivos iniciadores, siendo éstas diferentes en función de la cepa inoculada. También se observó en los vinos inoculados la inhibición del crecimiento de la microbiota láctica autóctona durante al vinificación.BIOLOGICAL ACIDIFICATION OF HIGH PH WINES BY USE OF LACTIC ACID BACTERIA Nowadays, wines are being affected by global warming. In recent years, earlier vintages and grapes with imbalance between phenolic ripeness and sugar ripeness are obtained. These grapes generate musts with high sugar concentration and low acids concentrations. These grape musts results in wines with high ethanol concentration, low total acidity and high pH. High pH wines have several disadvantages. They are wines without freshness and with high microbiological susceptibility. In addition, high pH in wines cause a decrease in the sulfur dioxide antiseptic capacity. As a solution to this problem, the pH of wines can be lowered by physical, chemical and biological acidification methods. The advantages of using biological methods are that nowadays they are not regulated by legislation and also can be used in organic vinifications. Several authors have developed biological acidification strategies using acid-producer yeasts, but they have not been very success. We propose the alternative use of lactic acid bacteria (LAB) to induce biological acidification in high pH wines. For this, we can exploit LAB metabolism to transform sugars into lactic acid by lactic fermentation and so we can decrease the pH of wines. Besides the synthesis of lactic acid, the metabolism of other acids can affect on pH of wines. Firstly, malic acid synthesis by yeasts decrease the pH of wine, but its degradation by LAB during malolactic fermentation (MLF) can increase it. However, MLF is beneficial in wines because that improves organoleptically and increases the microbiological stability. From the five genera of LAB associated to vinification, Lactobacillus genus was proposed to induce biological acidification in wines. This genus has better growth and metabolism at high pH than others genus. Indeed, some strains are tolerant to ethanol and SO2. A wide variety of enzymes for synthesize favorable aromatic compounds in wines have been described in Lactobacillus genus. Also some strains synthesize bacteriocins that promote their implantation in vinification process. Four objectives have been established in this Doctoral Thesis: the selection of Lactobacillus strains to induce biological acidification in wines, the optimization of biological acidification process, the obtainment of freeze-dried starter cultures of acidifying bacteria and the evaluation of designed acidification process in experimental vinifications. To carry out the selection of acidifying strains, Lactobacillus strains of different species of Enolab Collection have been used. These strains were previously isolated of spontaneous vinification processes. MC broth pH 3.5, based on white grape must, was used for laboratory assays. The selection program of strains was based on a scored system with first order criteria and second order criteria. Have been considered first order criteria that strains grew more than 70 units of area under curve (AUC), that they carried out the MLF, that they descended the pH of must more than 0.35 units and that they synthesized more than 12 g/L of lactic acid by lactic fermentation (LF). Strains that achieved first order criteria were scored with 10 points. The second order criteria were the resistance to lysozyme and SO2. Strains more resistant to these compounds were scored with 5 points. In final selection, highest scored strains, which were Enolab 4607 and Enolab 4608, both of L. plantarum were selected. Selected strains were characterized about their metabolism in MC broth and their ability to synthesize biogenic amines. At the end of one week culture in MC broth, selected strains decreased pH of must 0.73 units, consumed between 20 and 30 g/L of sugars and synthesized between 12 and 12.5 g/L of lactic acid by LF. Moreover, selected strains performed the MLF and consumed 100% of citric acid but did not form acetic acid. Regarding to production of biogenic amines, both strains were unable to synthesize histamine and putrescine. Both strains have got tdc gene but they did not synthesize tyramine or synthesize it in low amounts. To optimize the biological acidification process, several specific targets were established. LAB inoculation strategy during winemaking was determined, a period of acidification was estimated, a fermentative yeast to carry out alcoholic fermentation was choosed and other factors that may affect the acidification process were evaluated. The inoculation of LAB in must previously to yeasts were established as inoculation strategy to carry out the acidification process. Under these conditions, inoculated LAB were able to grow until the yeast inoculation, synthesizing large amounts of lactic acid and degrading completely the malic acid. Furthermore, a period between 48 and 72 hours was established as a suitable period between inoculation LAB and yeasts. Along this time, Enolab 4608 synthesized between 8 and 10 g/L of lactic acid, carried out the MLF and decreased the pH of must between 0.2 and 0.3 units. Enolab 4608 and Enoferm VN® were the yeast-bacteria combination which generated the best results in winemaking process coupled to biological acidification. The highest concentration of viable bacteria along winemaking was obtained through this yeast-bacteria combination. Indeed, by this way the highest levels of lactic acid and further acidification were generated. Other factors that may affect on acidification process were evaluated, such as the pH of the must, the presence of indigenous microbiota and polyphenols and the addition of lysozyme and SO2. The acidification of wine was more effective the further pH of must. Also, in presence of indigenous microbiota the behavior of LAB were highly influenced. Polyphenols also had a negative influence on the growth and acidifying ability of LAB. The SO2 affected more than lysozyme to viability of LAB. No production of lactic acid and acidification were observed in media with 0.1 mg/mL of SO2 or more. Obtain starter cultures of acidifying LAB strains for their inoculation in industrial vinifications were the third objective. To obtain highly effective starter cultures, a manufacture process for biomass production and freeze-drying were selected. Furthermore, it was determined that the bacterial metabolic system was activated more effectively by rehidratation of starters with OptimaloPlus® 2% or Nutrient VitEnd® 2%. By this fact, LAB culture was more active after their inoculation in must. The fourth objective was the evaluation of the biological acidification process designed in industrial vinifications. In these vinifications, acidification levels were not as high as those generated in laboratory vinifications. Indeed, in any winemaking the MLF were carried out by inoculated LAB. However, inoculated LAB were in a viable state at concentrations between 1 x 103 and 1 x 105 cfu/mL and an inhibition of indigenous lactic microbiota was generated. These facts reported that the metabolic activity of LAB was inhibited. By contrast, favorable organoleptic modification in wines inoculated by acidifying bacteria were observed and these were different depending on LAB strain

An Analysis of and Perspective on the Information Security Maturity Model: a case study of a Public and a Private Sector Company

Information Security (IS) is a concept that is related to protecting a set of data in order to preserve the value it has for an individual or an organization. A review of the literature shows there are four main aspects related to IS: confidentiality, integrity, availability and non-repudiation. Based on these four aspects, a new framework is put forward for analyzing the information security maturity model (ISMM) in an organization, assuming that each organization has a minimum level of information security policies in each aspect, taking into consideration the percentage of policies that this organization has from all those cited in our model. At the end, a case study was conducted in order to analyze the ISMM of a public and private sector company

A MODEL FOR EVALUATING INFORMATION SECURITY WITH A FOCUS ON THE USER

This study presents a theoretical model to evaluate the level of information security in an organizational environment with a focus on the knowledge, attitudes and behaviour of the end user, identifying the level and origin of the gap between the information security guidelines laid down by the company and the actual practices of its internal staff, third party partners and suppliers. The model is designed to assist in meeting the objectives and policies set for the management of information security by senior management, and contributes to maintaining an effective program of training and in raising awareness on information security

POLAR: Instrument and Results

We describe the design, performance, and results of a polarimeter used to make precision measurements of the 2.7 K cosmic microwave background. In the Spring of 2000 the instrument searched for polarized emission in three microwave frequency bands spanning 26–36 GHz. The instrument achieved high sensitivity and long-term stability, and has produced the most stringent limits to date on the amplitude of the large angular scale polarization of the cosmic microwave background radiation