Search results for "bacteri"
showing 10 items of 5466 documents
Different Modes of Regulation of the Expression of Dextransucrase in
2019
Leuconostoc lactis AV1 strain isolated from a Tunisian avocado was characterized as a dextran producer. The promoter PdsrLL and the dsrLL gene encoding the DsrLL dextransucrase responsible for the dextran synthesis were transcriptionally fused to the mCherry coding gene generating the pRCR20 plasmid. Upon plasmid transfer, both AV1n and the dextran non-producing Leuconostoc mesenteroides CM70 became red due to expression of the mCherry from the PdsrLL-dsr-mrfp transcriptional fusion. Characterization of the polymers present in cultures supernatants revealed that the DsrLL encoded from pRCR20 in the recombinant bacteria was able to synthesize dextran. The production of dextran by the DsrLL i…
Estudio de la reducción química y biológica de hongos y micotoxinas en pan
2017
El deterioro de los alimentos causado por los hongos que producen micotoxinas representa un problema importante en seguridad alimentaria. Los cereales en grano y sus productos derivados, como el pan, frecuentemente están contaminados con hongos micotoxigénicos. Es por ello que en la presente Tesis Doctoral se han estudiado la presencia de 17 micotoxinas en 80 muestras de pan de molde y el riesgo de exposición de la población a estos compuestos. Aflatoxinas (AFs), zearalenona (ZEA) y eniatinas (ENs) han sido detectadas respectivamente en el 20%, 65% y 96% de las muestras de pan analizadas. La presencia de dichas micotoxinas y, sobre todo, de las muestras en las que las AFs y la ZEA superan e…
Dextransucrase Expression Is Concomitant with that of Replication and Maintenance Functions of the pMN1 Plasmid in
2017
The exopolysaccharide synthesized by Lactobacillus sakei MN1 is a dextran with antiviral and immunomodulatory properties of potential utility in aquaculture. In this work we have investigated the genetic basis of dextran production by this bacterium. Southern blot hybridization experiments demonstrated the plasmidic location of the dsrLS gene, which encodes the dextransucrase involved in dextran synthesis. DNA sequencing of the 11,126 kbp plasmid (pMN1) revealed that it belongs to a family which replicates by the theta mechanism, whose prototype is pUCL287. The plasmid comprises the origin of replication, repA, repB, and dsrLS genes, as well as seven open reading frames of uncharacterized f…
Development of molecular approaches for direct detection and quantification of wine-related microorganisms
2018
En esta tesis doctoral se han desarrollado procedimientos para la detección y cuantificación de levaduras y bacterias acéticas totales y, en concreto, de las especies más importantes en la vinificación como Saccharomyces cerevisiae, Brettanomyces bruxellensis, Zygosaccharomyces bailii, L. plantarum, y O. oeni. Las estrategias que se han utilizado para el desarrollo de nuevos métodos se centran fundamentalmente en la supresión del paso de extracción previa de ADN y de los procedimientos de eliminación de inhibidores de la reacción de PCR presentes en las muestras. Para llevar a cabo este objetivo general, se establecieron los siguientes objetivos específicos; 1, desarrollo de un método de qP…
Sourdough and cereal-based foods: traditional and innovative products
2017
Cereals represent the main crop of the five continents and contribute greatly to the diet of several populations. Cereals often undergo a fermentation before eating. This process is fundamental to confer high sensory quality, as well as to preserve and enhance the nutritional and safety aspects of the resulting products. Fermented cereal based foods are complex microbial ecosystems, mainly represented by lactic acid bacteria and yeasts. Among these products, sourdough is worldwide applied to produce breads. Sourdough technology is also used to improve the final characteristics of fortified and gluten–free breads. This chapter focuses on the use of cereals to produce the most relevant fermen…
Estrategias biotecnológicas para reducir el contenido en fitatos en productos fermentados de origen vegetal mediante fitasas de bifidobacterias
2015
Los alimentos integrales de origen vegetal, concretamente, los cereales de grano entero y leguminosas se caracterizan por ser una fuente excelente de fibra dietética y poseer un elevado contenido en compuestos fitoquímicos. Además de proporcionar macronutrientes, como carbohidratos complejos y proteínas, también destacan por su contenido en micronutrientes como son las vitaminas y minerales. Sin embargo, su ingesta conlleva a la vez un aporte en sustancias antinutritivas, como los fitatos, con gran afinidad por minerales, proteínas y elementos traza, que pueden comprometer su absorción por formación de quelatos estables en el tracto digestivo. Una hidrólisis o defosforilación parcial de los…
Immunoaffinity purification and characterization of mitochondrial membrane-bound D-3-hydroxybutyrate dehydrogenase from Jaculus orientalis.
2008
Abstract Background The interconversion of two important energy metabolites, 3-hydroxybutyrate and acetoacetate (the major ketone bodies), is catalyzed by D-3-hydroxybutyrate dehydrogenase (BDH1: EC 1.1.1.30), a NAD+-dependent enzyme. The eukaryotic enzyme is bound to the mitochondrial inner membrane and harbors a unique lecithin-dependent activity. Here, we report an advanced purification method of the mammalian BDH applied to the liver enzyme from jerboa (Jaculus orientalis), a hibernating rodent adapted to extreme diet and environmental conditions. Results Purifying BDH from jerboa liver overcomes its low specific activity in mitochondria for further biochemical characterization of the e…
Extremophilic microbial communities on photovoltaic panel surfaces: a two‐year study
2020
Solar panel surfaces can be colonized by microorganisms adapted to desiccation, temperature fluctuations and solar radiation. Although the taxonomic and functional composition of these communities has been studied, the microbial colonization process remains unclear. In the present work, we have monitored this microbial colonization process during 24 months by performing weekly measurements of the photovoltaic efficiency, carrying out 16S rRNA gene high‐throughput sequencing, and studying the effect of antimicrobial compounds on the composition of the microbial biocenosis. This is the first time a long‐term study of the colonization process of solar panels has been performed, and our results…
A real-time PCR quantitative detection assay for Pseudomonas savastanoi pv. nerii in Nerium oleander
2008
A real-time PCR assay based on TaqMan chemistry was developed for the detection of Pseudomonas savastanoi pathovars that cause bacterial knot disease on different plant species. Primers and probe sequences were based on the iaaL gene coding for (indole-3-acetyl)-L-lysine synthetase and previously used in conventional PCR tests. Assay specificity was tested with an extended range of strains of P. savastanoi from eight hosts, with 13 other Pseudomonas spp., and with other microorganisms naturally occurring on or in oleander plants. A pure culture cell suspension was quantifi ed over a seven log concentration range (108 to 102 cfu ml-1 ). Different protocols were developed for the detection an…
Chemical Composition and Antibacterial Activity of Essential Oils from Different Parts of Bupleurum rotundifolium L.
2012
WOS: 000306925400016