Esteban R.,University of the Basque Country |
Esteban R.,Agrobiotechnology Institute |
Fernandez-Marin B.,University of the Basque Country |
Becerril J.M.,University of the Basque Country |
Garcia-Plazaola J.I.,University of the Basque Country
Tree Physiology | Year: 2014
The photosynthesis in evergreen trees living in Mediterranean ecosystems is subjected to multiple climatic stresses due to water shortage and high temperatures during the summer and to low temperatures during the winter. Mediterranean perennials deploy different photoprotective mechanisms to prevent damage to the photosynthetic system. Wax accumulation in leaves is a primary response which by enhancing light scattering in the leaf surface reduces incident radiation in the mesophyll. The existence of high variability in wax accumulation levels between coexisting individuals of a species has a visual effect on colour that provides distinguishable green and glaucous phenotypes. We explored this variability in a Mediterranean evergreen tree Juniperus thurifera (L.) to evaluate the impact of epicuticular wax on optical and ecophysiological properties and on the abundance of photoprotective pigments throughout an annual cycle. Because of light attenuation by waxes, we expected that glaucous phenotypes would lower the need for photoprotective pigments. We evaluated the effect of phenotype and season on reflectance, defoliation levels, photochemical efficiency and photoprotective pigment contents in 20 green and 20 glaucous junipers. Contrary to our expectations, the results showed that glaucous trees suffered from a diminution in photochemical efficiency, but there was no reduction in photoprotective pigments. Differences between glaucous and green phenotypes were greater in winter, which is the most stressful season for this species. Glaucous individuals also showed the highest levels of leaf defoliation. The lower photochemical efficiency of glaucous trees, together with higher defoliation rates and equal or greater number of physiological photoprotective mechanisms, suggests that in spite of wax accumulation, glaucous trees suffer from more severe stress than green ones. This result suggests that changes in colouration in Mediterranean evergreens may be a decline indicator. © 2014 The Author.
Grant O.M.,Institute Tecnologia Quimica e Biologica |
Grant O.M.,University College Dublin |
Tronina L.,Institute Tecnologia Quimica e Biologica |
Garcia-Plazaola J.I.,Agrobiotechnology Institute |
And 5 more authors.
Functional Plant Biology | Year: 2015
Shrubs often form the understorey in Mediterranean oak woodlands. These shrubs are exposed to recurrent water deficits, but how they will respond to predicted future exacerbation of drought is not yet understood. The ecophysiology of the shrub Cistus salvifolius L. was studied over the summer of 2005, which was during a heat-wave superimposed on the most severe drought in the Iberian Peninsula in the last 140 years. Branch water potential fell drastically during the summer, accompanied by stomatal closure and downregulation of PSII, with a concomitant loss of chlorophyll in the leaves. A parallel increase in the ratio of light-dissipating to light-capturing pigments and the proportion of xanthophyll cycle pigments in the de-epoxidated state, along with alterations in the structure of the light harvesting complex, may have reduced the potential for damage to leaves. Substantial increases in leaf tocopherol content during high radiation may have reduced damage from free radicals. Following autumn rains, leaves of the same shrubs showed physiological recovery, indicating the resilience of this Mediterranean species, for which an extremely dry hydrological year with 45% less rainfall than average, did not prevent healthy leaf functioning in response to renewed soil moisture availability. © 2015 CSIRO.
Volgger M.,University of Vienna |
Lang I.,University of Vienna |
Ovecka M.,Agrobiotechnology Institute |
Ovecka M.,Slovak Academy of Sciences |
Lichtscheidl I.,University of Vienna
Protoplasma | Year: 2010
We analysed cell wall formation in rapidly growing root hairs of Triticum aestivum under reduced turgor pressure by application of iso- and hypertonic mannitol solutions. Our experimental series revealed an osmotic value of wheat root hairs of 150 mOsm. In higher concentrations (200-650 mOsm), exocytosis of wall material and its deposition, as well as callose synthesis, still occurred, but the elongation of root hairs was stopped. Even after strong plasmolysis when the protoplast retreated from the cell wall, deposits of wall components were observed. Labelling with DiOC6(3) and FM1-43 revealed numerous Hechtian strands that spanned the plasmolytic space. Interestingly, the Hechtian strands also led towards the very tip of the root hair suggesting strong anchoring sites that are readily incorporated into the new cell wall. Long-term treatments of over 24 h in mannitol solutions (150-450 mOsm) resulted in reduced growth and concentration-dependent shortening of root hairs. However, the formation of new root hairs does occur in all concentrations used. This reflects the extraordinary potential of wheat root cells to adapt to environmental stress situations. © 2009 Springer-Verlag.
Rumbo-Feal S.,University of La Coruña |
Gomez M.J.,CSIC - National Institute of Aerospace Technology |
Gayoso C.,University of La Coruña |
Alvarez-Fraga L.,University of La Coruña |
And 9 more authors.
PLoS ONE | Year: 2013
Acinetobacter baumannii has emerged as a dangerous opportunistic pathogen, with many strains able to form biofilms and thus cause persistent infections. The aim of the present study was to use high-throughput sequencing techniques to establish complete transcriptome profiles of planktonic (free-living) and sessile (biofilm) forms of A. ATCC 17978 and thereby identify differences in their gene expression patterns. Collections of mRNA from planktonic (both exponential and stationary phase cultures) and sessile (biofilm) cells were sequenced. Six mRNA libraries were prepared following the mRNA-Seq protocols from Illumina. Reads were obtained in a HiScanSQ platform and mapped against the complete genome to describe the complete mRNA transcriptomes of planktonic and sessile cells. The results showed that the gene expression pattern of A. baumannii biofilm cells was distinct from that of planktonic cells, including 1621 genes over-expressed in biofilms relative to stationary phase cells and 55 genes expressed only in biofilms. These differences suggested important changes in amino acid and fatty acid metabolism, motility, active transport, DNA-methylation, iron acquisition, transcriptional regulation, and quorum sensing, among other processes. Disruption or deletion of five of these genes caused a significant decrease in biofilm formation ability in the corresponding mutant strains. Among the genes over-expressed in biofilm cells were those in an operon involved in quorum sensing. One of them, encoding an acyl carrier protein, was shown to be involved in biofilm formation as demonstrated by the significant decrease in biofilm formation by the corresponding knockout strain. The present work serves as a basis for future studies examining the complex network systems that regulate bacterial biofilm formation and maintenance. © 2013 Rumbo-Feal et al.
Zamarreno C.R.,Public University of Navarra |
Ardaiz I.,Public University of Navarra |
Ruete L.,Public University of Navarra |
Munoz F.J.,Agrobiotechnology Institute |
And 2 more authors.
IEEE SENSORS 2013 - Proceedings | Year: 2013
This work presents the development of a fast response, low cost and real time monitoring biosensor for sepsis diagnosis by means of the detection of C-reactive protein (CRP) as a sepsis biomarker. The developed sensor has two main features. The first one consists of the utilization of high sensitive optical fiber refractometers based on Lossy Mode Resonances (LMRs). The second is the utilization of CRP-selective and high sensitive aptamer chains as the sensing element (bio-receptor). Thin polymer/aptamer films were fabricated using the Layer-by-Layer (LbL) technique onto the optical fiber device in order to facilitate the detection of the aptamer refractive index changes in presence of CRP. Obtained devices were able to discriminate between a non-pathological concentration (2mg/L) and a pathological concentration (20mg/L) of CRP in less than 15 min. In addition, these sensors could be reused after a proper decontamination process which enhances their lifetime. © 2013 IEEE.
Razquin L.,Public University of Navarra |
Zamarreno C.R.,Public University of Navarra |
Munoz F.J.,Agrobiotechnology Institute |
Matias I.R.,Public University of Navarra |
Arregui F.J.,Public University of Navarra
Proceedings of IEEE Sensors | Year: 2012
An optical fiber sensor using an aptamer receptor has been developed for the detection of thrombin. The sensitive coating consists of an aptamer-polymer structure fabricated using the layer-by-layer electrostatic self assembly technique onto novel optical fiber refractometers based on lossy mode resonances (LMRs). LMR based refractometers enable to overcome the traditional drawbacks of surface Plasmon resonance (SPR) based devices, such as the utilization of polarized light for example. The refractometer is based on an indium tin oxide thin layer deposited by DC-sputtering onto the cladding removed multimode fiber. These refractometers enable to monitor the variations of the surrounding medium refractive index (RI). Hence, RI variations of the outer film induced by thrombin can be referenced to the LMR wavelength shift. The described configuration has enabled the detection of low concentrations of thrombin (100nM) as well as obtaining a maximum wavelength shift of 50 nm at higher (1μM) concentrations. © 2012 IEEE.