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Warren C.R.,University of Sydney | Aranda I.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Cano F.J.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Cano F.J.,Technical University of Madrid
Metabolomics | Year: 2012

Past studies of water stress in Eucalyptus spp. generally highlighted the role of fewer than five "important" metabolites, whereas recent metabolomic studies on other genera have shown tens of compounds are affected. There are currently no metabolite profiling data for responses of stress-tolerant species to water stress. We used GC-MS metabolite profiling to examine the response of leaf metabolites to a long (2 month) and severe (Ψ predawn < -2 MPa) water stress in two species of the perennial tree genus Eucalyptus (the mesic Eucalyptus pauciflora and the semi-arid Eucalyptus dumosa). Polar metabolites in leaves were analysed by GC-MS and inorganic ions by capillary electrophoresis. Pressure-volume curves and metabolite measurements showed that water stress led to more negative osmotic potential and increased total osmotically active solutes in leaves of both species. Water stress affected around 30-40% of measured metabolites in E. dumosa and 10-15% in E. pauciflora. There were many metabolites that were affected in E. dumosa but not E. pauciflora, and some that had opposite responses in the two species. For example, in E. dumosa there were increases in five acyclic sugar alcohols and four lowabundance carbohydrates that were unaffected by water stress in E. pauciflora. Re-watering increased osmotic potential and decreased total osmotically active solutes in E. pauciflora, whereas in E. dumosa re-watering led to further decreases in osmotic potential and increases in total osmotically active solutes. This experiment has added several extra dimensions to previous targeted analyses of water stress responses in Eucalyptus, and highlights that even species that are closely related (e. g. congeners) may respond differently to water stress and re-watering. © 2011 Springer Science+Business Media, LLC.


Warren C.R.,University of Sydney | Aranda I.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Cano F.J.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Cano F.J.,Technical University of Madrid
Plant, Cell and Environment | Year: 2011

Studies of water stress commonly examine either gas exchange or leaf metabolites, and many fail to quantify the concentration of CO2 in the chloroplasts (Cc). We redress these limitations by quantifying Cc from discrimination against 13CO2 and using gas chromatography-mass spectrometry (GC-MS) for leaf metabolite profiling. Five Eucalyptus and two Acacia species from semi-arid to mesic habitats were subjected to a 2 month water stress treatment (Ψpre-dawn=-1.7 to -2.3MPa). Carbohydrates dominated the leaf metabolite profiles of species from dry areas, whereas organic acids dominated the metabolite profiles of species from wet areas. Water stress caused large decreases in photosynthesis and Cc, increases in 17-33 metabolites and decreases in 0-9 metabolites. In most species, fructose, glucose and sucrose made major contributions to osmotic adjustment. In Acacia, significant osmotic adjustment was also caused by increases in pinitol, pipecolic acid and trans-4-hydroxypipecolic acid. There were also increases in low-abundance metabolites (e.g. proline and erythritol), and metabolites that are indicative of stress-induced changes in metabolism [e.g. γ-aminobutyric acid (GABA) shunt, photorespiration, phenylpropanoid pathway]. The response of gas exchange to water stress and rewatering is rather consistent among species originating from mesic to semi-arid habitats, and the general response of metabolites to water stress is rather similar, although the specific metabolites involved may vary. Studies of water stress commonly examine either gas exchange or leaf metabolites, and many gas exchange studies fail to quantify the concentration of CO2 in the chloroplasts (Cc). This study provides a more holistic picture of how water stress affects metabolism by quantifying Cc from discrimination against 13CO2 and using GC-MS for leaf metabolite profiling. We show that in a range of Eucalyptus and Acacia species water stress decreases photosynthesis and Cc, increases amounts of 17-33 metabolites and decreases amounts of 0-9 metabolites. In addition to the well-known abundant metabolites that gave rise to osmotic adjustment, there were also changes in low-abundance metabolites that likely help plants cope with drought via non-osmotic roles (e.g. stabilisation of membranes and proteins), and metabolites that are indicative of stress-induced changes in metabolism (e.g. GABA shunt, photorespiration, pinitol synthesis, phenylpropanoid pathway). © 2011 Blackwell Publishing Ltd.


Ortiz S.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Lopez V.,Institute Salud Carlos III | Martinez-Suarez J.V.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Food Microbiology | Year: 2014

The aims of this study were to characterize the different strains of Listeria monocytogenes collected at an Iberian pork processing plant and to investigate whether their specific characteristics were associated with prolonged survival in the plant. Using pulsed-field gel electrophoresis (PFGE), 29 PFGE types were previously identified during a three-year period. Eight of these PFGE types persisted in the plant during that period. In the present study, a subset of 29 PFGE type strains, which represented the 29 different PFGE types, was further characterized by assessing the potential virulence, and using motility, surface attachment, and antimicrobial susceptibility tests. After changing the disinfection procedures in the plant, the isolation rate of L.monocytogenes decreased, and only four of the 29 PFGE types, including three of the eight persistent PFGE types, were found the following year. These four "surviving" PFGE types included three from PCR serogroup IIa that were characterized by their low virulence mutations and low-level resistance to benzalkonium chloride (BAC). Furthermore, these PFGE types comprised the only BAC-resistant isolates found in the study, and they appear to have been selected due to the control of Listeria contamination. The resistance to increased sublethal concentrations of disinfectants may lead to prolonged survival of L.monocytogenes in food plants. © 2013 Elsevier Ltd.


Martin-Sampedro R.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Eugenio M.E.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Villar J.C.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Bioresource Technology | Year: 2012

A non-wood raw material with high potential for pulp and paper applications (Hesperaloe funifera) was subjected to a steam explosion pre-treatment, and the subsequent effect of this pretreatment on biopulping and biobleaching was studied. An increase in the delignification rate, bigger than that reported for autohydrolysis and acid hydrolysis pre-treatments, and a reduction in chemical consumption were found during kraft pulping of the exploded samples. However, biopulping with the laccase-mediator system (LMS) did not lead to a reduction in the kappa number in either non-exploded or exploded unbleached pulps. On the other hand, the steam explosion pretreatment boosted the advantages of the LMS pre-treatment (decrease in kappa number and increase in brightness) favored biobleaching, with a 53.1% delignification rate and a final brightness of 67% ISO. Finally, the steam explosion pre-treatment also improved the color properties of the bleached pulp and reduced the hydrogen peroxide consumption by 24.6%. © 2012 Elsevier Ltd.


Landete J.M.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Trends in Biotechnology | Year: 2016

Bacteria respond to their external environment by modulating gene expression in the presence of certain effector molecules. The adaptive responses are mediated by transcriptional regulators that, after binding to the DNA, recognize these effector molecules and modify transcription. Some applications of regulatory proteins are reviewed here. © 2016 Elsevier Ltd.


Perez-Ramirez E.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Llorente F.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Jimenez-Clavero M.A.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Viruses | Year: 2014

Avian models of West Nile virus (WNV) disease have become pivotal in the study of infection pathogenesis and transmission, despite the intrinsic constraints that represents this type of experimental research that needs to be conducted in biosecurity level 3 (BSL3) facilities. This review summarizes the main achievements of WNV experimental research carried out in wild birds, highlighting advantages and limitations of this model. Viral and host factors that determine the infection outcome are analyzed in detail, as well as recent discoveries about avian immunity, viral transmission, and persistence achieved through experimental research. Studies of laboratory infections in the natural host will help to understand variations in susceptibility and reservoir competence among bird species, as well as in the epidemiological patterns found in different affected areas. © 2014 by the authors; licensee MDPI, Basel, Switzerland.


Blazquez A.-B.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Saiz J.-C.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Virus Research | Year: 2010

Since its first detection in New York in 1999, West Nile virus (WNV) has already caused over 1000 human deaths in the U.S. Although the virus is usually transmitted by mosquito bites; other routes, such as intrauterine and breastfeeding, have been occasionally reported in humans. To investigate alternative routes of WNV transmission, mice were inoculated during gestation and after delivery, and offspring from infected and non-infected mothers were interchanged and nursed as foster babies. Intrauterine and breastfeeding transmission was confirmed after WNV detection, by quantitative RT-PCR and viral culture infectivity, in babies born to infected mothers and in newborns that were nursed by mothers infected after delivery. All infected mothers, either experimentally or after cannibal ingestion of infected fostered babies, succumbed to the disease, as did most of their nursed babies. These results indicate that WNV is efficiently transmitted by vertical routes (intrauterine and lactation) and after cannibal ingestion of infected animals. © 2010 Elsevier B.V.


Martin-Sampedro R.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Eugenio M.E.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Villar J.C.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Bioresource Technology | Year: 2011

The aim of this work was to evaluate the response to biobleaching of steam exploded kraft pulps and to compare the results with the controls. For this end, a laccase-mediator treatment using commercial laccase (Novozyme 51003) and a natural mediator (acetosyringone) were assayed, followed by alkaline extraction and hydrogen peroxide stages. Our approach resulted in exploded biobleached pulps with lower kappa number and improved optical properties compared to controls, even after subjecting pulps to accelerated ageing. Additionally, use of hydrogen peroxide was reduced. The LMS (laccase-mediator system) had a smaller impact on the properties of the bleached pulps and on hydrogen peroxide consumption than the steam explosion process did. © 2010 Elsevier Ltd.


Landete J.M.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Critical Reviews in Biotechnology | Year: 2016

Lactic acid bacteria (LAB) have a long history of use in fermented foods and as probiotics. Genetic manipulation of these microorganisms has great potential for new applications in food safety, as well as in the development of improved food products and in health. While genetic engineering of LAB could have a major positive impact on the food and pharmaceutical industries, progress could be prevented by legal issues related to the controversy surrounding this technology. The safe use of genetically modified LAB requires the development of food-grade cloning systems containing only the DNA from homologous hosts or generally considered as safe organisms, and not dependent antibiotic markers. The rationale for the development of cloning vectors derived from cryptic LAB plasmids is the need for new genetic engineering tools, therefore a vision from cryptic plasmids to applications in food-grade vectors for LAB plasmids is shown in this review. Replicative and integrative vectors for the construction of food-grade vectors, and the relationship between resistance mechanism and expression systems, will be treated in depth in this paper. Finally, we will discuss the limited use of these vectors, and the problems arising from their use. © 2016 Taylor & Francis.


Lammel T.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Boisseaux P.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Fernandez-Cruz M.-L.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Navas J.M.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia
Particle and Fibre Toxicology | Year: 2013

Background: Graphene and graphene derivative nanoplatelets represent a new generation of nanomaterials with unique physico-chemical properties and high potential for use in composite materials and biomedical devices. To date little is known about the impact graphene nanomaterials may have on human health in the case of accidental or intentional exposure. The objective of this study was to assess the cytotoxic potential of graphene nanoplatelets with different surface chemistry towards a human hepatoma cell line, Hep G2, and identify the underlying toxicity targets.Methods: Graphene oxide (GO) and carboxyl graphene (CXYG) nanoplatelet suspensions were obtained in water and culture medium. Size frequency distribution of the suspensions was determined by means of dynamic light scattering. Height, lateral dimension and shape of the nanoplatelets were determined using atomic force and electron microscopy. Cytotoxicity of GO and CXYG nanoplatelets was assessed in Hep G2 cells using a battery of assays covering different modes of action including alterations of metabolic activity, plasma membrane integrity and lysosomal function. Induction of oxidative stress was assessed by measuring intracellular reactive oxygen species levels. Interaction with the plasma membrane, internalization and intracellular fate of GO and CXYG nanoplatelets was studied by scanning and transmission electron microscopy.Results: Supplementing culture medium with serum was essential to obtain stable GO and CXYG suspensions. Both graphene derivatives had high affinity for the plasma membrane and caused structural damage of the latter at concentrations as low as 4 μg/ml. The nanoplatelets penetrated through the membrane into the cytosol, where they were concentrated and enclosed in vesicles. GO and CXYG accumulation in the cytosol was accompanied by an increase in intracellular reactive oxygen species (ROS) levels, alterations in cellular ultrastructure and changes in metabolic activity.Conclusions: GO and CXYG nanoplatelets caused dose- and time-dependent cytotoxicity in Hep G2 cells with plasma membrane damage and induction of oxidative stress being important modes of toxicity. Both graphene derivatives were internalized by Hep G2, a non-phagocytotic cell line. Moreover, they exerted no toxicity when applied at very low concentrations (< 4 μg/ml). GO and CXYG nanoplatelets may therefore represent an attractive material for biomedical applications. © 2013 Lammel et al.; licensee BioMed Central Ltd.

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