Aspergillus niger citrate exporter revealed by comparison of two alternative citrate producing conditions

Currently, there is no consensus regarding the mechanism underlying Aspergillus niger citrate biosynthesis and secretion. We hypothesise that depending on the experimental setup, extracellular citrate accumulation can have fundamentally different underlying transcriptomic landscapes. We show that varying the amount and type of supplement of an arginine auxotrophic A. niger strain results in transcriptional down-regulation of citrate metabolising enzymes in the condition in which more citrate is accumulated extracellularly. This contrasts with the transcriptional adaptations when increased citrate production is triggered by iron limitation. By combining gene expression data obtained from these two very distinct experimental setups with hidden Markov models and transporter homology approaches, we were able to compile a shortlist of the most likely citrate transporter candidates. Two candidates (An17g01710 and An09g06720m.01) were heterologously expressed in the yeast Saccharomyces cerevisiae, and one of the resultant mutants showed the ability to secrete citrate. Our findings provide steps in untangling the complex interplay of different mechanisms underlying A. niger citrate accumulation, and we demonstrate how a comparative transcriptomics approach complemented with further bioinformatics analyses can be used to pinpoint a fungal citrate exporter

Perturbing Topological Field Theories

The abelian Chern-Simons theory is perturbed by introducing local gauge-invariant interaction terms depending on the curvature. The computation of the correlation function of two Wilson lines for two smooth closed nonintersecting curves is reported up to four loops and is shown to be unaffected by radiative corrections. This result ensures the stability of the linking number of the two curves with respect to the local perturbations which may be added to the Chern-Simons action.Comment: 13 pages, 5 figures, corrected some typo

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Photocatalytic NOx abatement:mathematical modeling, CFD validation and reactor analysis

\u3cp\u3eA 2D CFD model was implemented for the numerical simulation of NO \u3csub\u3ex\u3c/sub\u3e abatement in a photocatalytic reactor, considering the effect of relative humidity (10–60%), light intensity (0.3–13 W⋅m \u3csup\u3e−2\u3c/sup\u3e) and inlet NO concentration (0.1–1.0 ppm). Significant differences of NO \u3csub\u3ex\u3c/sub\u3e concentration at the catalytic surface and bulk gas were found (Δ \u3csub\u3emax\u3c/sub\u3e of ∼12% and ∼16% for NO and NO \u3csub\u3e2\u3c/sub\u3e, respectively) and corrections were proposed to achieve intrinsic rate laws from a model available in the literature. An analysis of the reactor performance was conducted and a nonlinear behavior was observed when the channel height (H) was varied. A point of maximum for the integral rate of NO and NO \u3csub\u3e2\u3c/sub\u3e consumption as a function of H was found (Δ \u3csub\u3eNO\u3c/sub\u3e of ∼2% and ∼-1% for H→2H→4H; Δ \u3csub\u3eNO \u3csub\u3e2\u3c/sub\u3e \u3c/sub\u3e of ∼46% and -8.5% for H→2H→4H). Additionally, the NO conversion decreased from ∼29% to ∼7% and the selectivity decreased from ∼85% to ∼80% (passing through a point of minimum at 2H) when the height was varied in the range H-4H. When comparing the results from the CFD simulations and the predictions of a plug flow model, deviations for NO conversion and selectivity increased with H (Δ \u3csub\u3emax\u3c/sub\u3e of ∼2% and ∼45%, respectively). \u3c/p\u3

Utilização de resíduos ou subprodutos de cortiça para a eliminação de óleos e gorduras de águas.

Este trabalho pretende apresentar a cortiça como um material competitivo para a resolução de problemas ambientais, nomeadamente a eliminação de gorduras hidro-solúveis ou dispersas em águas. Os métodos convencionais de tratamento, que incluem processos físicos/químicos, são muito eficientes na remoção de óleos e gorduras em concentrações elevadas, mas são ineficazes quando estes poluentes estão presentes em baixas concentrações, sendo necessário utilizar tecnologias dispendiosas de separação por membranas ou adsorção em carvão ativado. Nesse sentido, pretende-se encontrar um material de cortiça adequado, tendo em conta uma ampla diversidade de fontes e granulometrias, para esta aplicação, com o intuito de obter um efluente final com a qualidade exigível para a reutilização da água, reduzindo os custos associados ao consumo de água e taxas de descarga do efluente no emissário ou no meio hídrico natural, sem falar do benefício ambiental decorrente da redução de consumo de água pelas indústrias que utilizem esta tecnologia.A realização deste trabalho beneficia do financiamento concedido pela Agência de Inovação (programa QREN), no âmbito do projecto HidroCork. O trabalho também é suportado pelo projecto PEst- C/EQB/LA0020/2011, financiado pelo FEDER através do Programa Operacional Factores de Competitividade - COMPETE e pela Fundação para a Ciência e a Tecnologia - FCT

Effect of Cr (VI) in Four Portuguese Microalgae Growth

http://sherpa.ac.uk/romeo/issn/1582-9596/The objective of this work was to study the growth of microalgae Chlorella fusca ACOI 621, Chlorella vulgaris ACOI 879, Scenedesmus acutus ACOI 538 and Scenedesmus obliquus ACOI 550, in the presence and absence of Cr(VI). The microalgae growth was assessed as a function of different parameters, particularly, temperature, pH and Cr(VI) addition. Although growth inhibition due to Cr(VI) toxicity is rather visible for Cr(VI) ≥ 5 mg L-1, concentrations up to 1 mg L-1 seem not to seriously affect the algal growth. The production of metabolites (expressed in terms of dissolved organic carbon released from the microalgae to the solution) expresses the inhibition caused by toxic levels of Cr(VI) in the four microalgae, which adversely affects the sedimentation. The more marked effect of Cr(VI) on algal growth is observed in C. vulgaris culture and all these microalgae can be used for theremoval of heavy metals from wastewaters. All in all, C. fusca appears to be the best choice for work involving heavy metal removal.info:eu-repo/semantics/publishedVersio

Updating the difficulties of the Venezuelan scientific work

In Ibero-America and for more than 10 years, the Iberoamerican conference on Advanced Oxidation Technologies (CIPOA) has generated opportunities on the fundamentals and application of Advanced Oxidation Technologies (AOTs) in the environmental, energy and climate sectors, towards a sustainable and carbon-neutral circular economy. One of the member countries of the CIPOA conference is Venezuela, and in recent years its participation has been significantly reduced. Concerned about this situation, the CIPOA board would like to open a space to inform the scientific community of the reasons that affect Venezuelan scientific colleagues.Fil: Vargas Balda, Ronald Eduardo. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; Argentina. Universidad Simon Bolivar.; VenezuelaFil: Madriz Ruiz, Lorean Mercedes. Universidad Simon Bolivar.; Venezuela. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Vilar, Vitor J. P.. Universidad de Porto; PortugalFil: Fatta Kassinos, Despo. University Of Cyprus; Chipr

Water quality in Lis river, Portugal

In the past 30 years, the Lis river basin has been subjected to constant ecological disasters mainly due to piggery untreated wastewater discharges. The aim of this study was to evaluate the effect of existing domestic, agricultural, and industrial activities on the water quality, and to propose a watershed plan to protect and manage surface water resources within the Lis river basin. For this purpose, 16 monitoring stations have been strategically selected along the Lis river stretch and its main tributaries to evaluate the water quality in six different sampling periods (2003-2006). All samples were characterized in terms of organic material, nutrients, chlorophyll, and pathogenic bacteria. Generally, the Lis river presents poor water quality, according to environmental quality standards for surface water, principally in terms of dissolved oxygen, biochemical oxygen demand, total nitrogen, and fecal coliform, which can be associated mainly with the contamination source from pig-breeding farms

Laser-induced diffusion decomposition in Fe-V thin-film alloys

We investigate the origin of ferromagnetism induced in thin-film (similar to 20 nm) Fe-V alloys by their irradiation with subpicosecond laser pulses. We find with Rutherford backscattering that the magnetic modifications follow a thermally stimulated process of diffusion decomposition, with formation of a-few-nm-thick Fe enriched layer inside the film. Surprisingly, similar transformations in the samples were also found after their long-time (similar to 10(3) s) thermal annealing. However, the laser action provides much higher diffusion coefficients (similar to 4 orders of magnitude) than those obtained under standard heat treatments. We get a hint that this ultrafast diffusion decomposition occurs in the metallic glassy state achievable in laser-quenched samples. This vitrification is thought to be a prerequisite for the laser-induced onset of ferromagnetism that we observe. 2014 Elsevier B.V. All rights reserved