Adaptative mechanisms of cereals to climate change: the importance of nitrogen sources in soils.

200 p.La actividad humana y más concretamente, la industria, la agricultura, el consumo de combustibles fósiles, la deforestación, la quema de restos vegetales y la ganadería han provocado un rápido aumento de gases de efecto invernadero (GEI) en el último siglo. El Panel intergubernamental para el cambio climático (IPCC) está impulsando estrategias centradas en la reducción de estos GEI, así como promoviendo el empleo de nuevas variedades (de los principales cultivos) que mejor se puedan adaptar a las futuras condiciones atmosféricas.En ese trabajo se han abordado ambas estrategias mediante diferentes aproximaciones: a) empleo de inhibidores de la nitrificación asociados a fertilizantes de base amoniacal para reducir las emisiones de N2O derivadas de la fertilización y b) identificar el impacto del nitrógeno en las relaciones fuente-sumidero de C y en la capacidad de adaptación de variedades de cereales al incremento de CO2.Los resultados obtenidos permiten confirmar que el uso de los inhibidores analizados (DMPP y DMPSA) es una estrategia efectiva para reducir la emisión de N2O debido a la inhibición de las bacterias nitrificantes. Además, se pudo describir cómo estos compuestos estimulan una completa desnitrificación, mitigando la emisión de N2O por medio de una mayor reducción a N2. Por otro lado, se ha estudiado la respuesta de trigo frente a diferentes fuentes de nitrógeno (nitrato, amonio y nitrato amónico) en condiciones de CO2 ambiental (400 ppm) y elevado (700 ppm). Bajo condiciones de elevado CO2, la fertilización mixta o amoniacal permitió un mejor ajuste de carbohidratos foliares, al contrario que la fertilización nítrica. Por último, la importancia del desarrollo de sumideros de C en condiciones de elevado CO2 y el ajuste de la relación fuente-sumidero de C en hoja se estudió en plantas de cebada con diferente capacidad de almacenar compuestos carbonados y nitrogenados en el pedúnculo. Los resultados descritos confirman la necesidad identificar variedades con mayor capacidad de sumidero de C para así permitir un mayor ajuste del C foliar con la consiguiente mejora en la actividad fotosintética bajo condiciones de elevado CO2

Characterization of glycoproteins by capillary electrophoresis electrospray mass spectrometry (CE-ESI-MS). Applications to diagnosis in biomedicine

Glycosylation is the most common posttranslational modification in proteins and the carbohydrates participate in many biological processes. The number and type of glycoforms for a certain glycoprotein may change as a consequence of pathological processes. In our work a method for the separation of transferrin sialoforms has been developed, that permits the diagnostic of Congenital Disorders of Glycosylation (CDG) using a polybrene-dextran sulphate coating and CE-ESI-TOF methodologies. In order to improve the sensitivity the use of solid-phase extraction coupled on-line to CE-ESI-MS is studied and the SPE-CE-ESI-MS developed methods are applied for the characterization of rHuEPO glycoforms. The achieved separation and the high mass-resolving power of flight (TOF) mass detection allows to establish the most probable rHuEPO glycoforms

Determination of acidity constants and prediction of electrophoretic separation of amyloid beta peptides

In this paper we describe a strategy to estimate by CE the acidity constants (pKa) of complex polyprotic peptides from their building peptide fragments. CE has been used for the determination of the pKas of five short polyprotic peptides that cover all the sequence of amyloid beta (Aβ) peptides 1-40 and 1-42 (Aβ fragments 1-15, 10-20, 20-29, 25-35 and 33-42). First, the electrophoretic mobility (me) was measured as a function of pH of the background electrolyte (BGE) in the pH range 2-12 (bare fused silica capillary, I=25mM and T=25ºC). Second, the mes were fitted to equations modelling the ionisable behaviour of the different fragments as a function of pH to determine their pKas. The accuracy of the pKas was demonstrated predicting the electrophoretic behaviour of the studied fragments using the classical semiempirical relationships between me and peptide charge-to-mass ratio (me vs. q/Mr1/2, classical polymer model, q=charge and Mr=relative molecular mass). Separation selectivity in a mixture of the fragments as a function of pH was evaluated, taking into account the influence of the EOF at each pH value, and a method for the simple and rapid simulation of the electropherograms at the optimum separation pH was described. Finally, the pKas of the fragments were used to estimate the pKas of the Aβ peptides 1-40 and 1-42 (tC and D 3.1, E 4.6 and Y 10.8 for acidic amino acids and tN-D 8.6, H 6.0, K 10.6 and R 12.5 for basic amino acids), which were used to predict their behaviour and simulate their electropherograms with excellent results. However, as expected due to the very small differences on q/Mr1/2 values, separation resolution of their mixtures was poor over the whole pH range. The use of poly(vinyl alcohol) (PVA) coated capillaries allowed reducing the electroosmotic flow (EOF) and a slight improvement of resolution

Generating reference models for structurally complex data: application to the stabilometry medical domain

We present a framework specially designed to deal with structurally complex data, where all individuals have the same structure, as is the case in many medical domains. A structurally complex individual may be composed of any type of singlevalued or multivalued attributes, including time series, for example. These attributes are structured according to domain-dependent hierarchies. Our aim is to generate reference models of population groups. These models represent the population archetype and are very useful for supporting such important tasks as diagnosis, detecting fraud, analyzing patient evolution, identifying control groups, etc

Analysis of serum transthyretin by on-line immunoaffinity solid-phase extraction capillary electrophoresis mass spectrometry using magnetic beads

In this paper, an on-line immunoaffinity solid-phase extraction capillary electrophoresis mass spectrometry (IA-SPE-CE-MS) method using magnetic beads (MBs) is described for the analysis of serum transthyretin (TTR), which is a protein related to different types of amyloidosis. First, purification of TTR from serum was investigated by off-line immunoprecipitation and CE-MS. The suitability of three Protein A (ProA) MBs (Protein A Ultrarapid AgaroseTM (UAPA), Dynabeads® Protein A (DyPA) and SiMAG-Protein A (SiPA)) and AffiAmino Ultrarapid AgaroseTM (UAAF) MBs to prepare an IA sorbent with a polyclonal antibody (Ab) against TTR, was studied. In all cases results were repeatable and it was possible the identification and the quantitation of the relative abundance of the 6 most abundant TTR proteoforms. Although recoveries were the best with UAPA MBs, UAAF MBs were preferred for on-line immunopurification because Ab was not eluted from the MBs. Under the optimised conditions with standards in IA-SPE-CE-MS, microcartridge lifetime (>20 analyses/day) and repeatability (2.9 and 4.3 % RSD for migration times and peak areas) were good, the method was linear between 5- 25 µg·mL-1 and limit of detection (LOD) was around 1 µg·mL-1 (25 times lower than by CE-MS, 25 µg·mL-1). A simple off-line sample pretreatment based on precipitation of the most abundant proteins with 5% (v/v) of phenol was necessary to clean-up serum samples. The potential of the on-line method to screen for familial amyloidotic polyneuropathy type I (FAP-I), which is the most common hereditary systemic amyloidosis, was demonstrated analysing serum samples from healthy controls and FAP-I patients

Dimethylpyrazole-based nitrification inhibitors have a dual role in N2O emissions mitigation in forage systems under Atlantic climate conditions

[EN]Nitrogen fertilization is the most important factor increasing nitrous oxide (N2O) emissions from agriculture, which is a powerful greenhouse gas. These emissions are mainly produced by the soil microbial processes of nitrification and denitrification, and the application of nitrification inhibitors (NIs) together with an ammonium-based fertilizer has been proved as an efficient way to decrease them. In this work the NIs dimethylpyrazole phosphate (DMPP) and dimethylpyrazole succinic acid (DMPSA) were evaluated in a temperate grassland under environmental changing field conditions in terms of their efficiency reducing N2O emissions and their effect on the amount of nitrifying and denitrifying bacterial populations responsible of these emissions. The stimulation of nitrifying bacteria induced by the application of ammonium sulphate as fertilizer was efficiently avoided by the application of both DMPP and DMPSA whatever the soil water content. The denitrifying bacteria population capable of reducing N2O up to N-2 was also enhanced by both NIs provided that sufficiently high soil water conditions and low nitrate content were occurring. Therefore, both NIs showed the capacity to promote the denitrification process up to N-2 as a mechanism to mitigate N2O emissions. DMPSA proved to be a promising NI, since it showed a more significant effect than DMPP in decreasing N2O emissions and increasing ryegrass yield.This work was funded by the Spanish Government (AGL2015-64582-C3-2-R MINECO/FEDER and RTI2018-094623-B-C21 MCIU/AEI/FEDER, UE) , by the Basque Government (IT-932-16) and by EuroChem Agro Iberia S.L.-UPV/EHU 2015.0248 and 2016.0339. Ximena Huerfano was recipient of a specialization fellowship from the UPV/EHU for Ph.D. researchers

Differential Regulation of Stomatal Conductance as a Strategy to Cope With Ammonium Fertilizer Under Ambient Versus Elevated CO2

While nitrogen (N) derived from ammonium would be energetically less expensive than nitrate-derived N, the use of ammonium-based fertilizer is limited by the potential for toxicity symptoms. Nevertheless, previous studies have shown that exposure to elevated CO2 favors ammonium assimilation in plants. However, little is known about the impact of different forms of N fertilizer on stomatal opening and their consequent effects on CO2 and H2O diffusion in wheat plants exposed to ambient and elevated CO2. In this article, we have examined the response of the photosynthetic machinery of durum wheat (Triticum durum, var. Amilcar) grown with different types of N fertilizer (NO3−, NH4+, and NH4NO3) at 400 versus 700 ppm of CO2. Alongside gas exchange and photochemical parameters, the expression of genes involved in CO2 (PIP1.1 and PIP2.3) and H2O (TIP1) diffusion as well as key C and N primary metabolism enzymes and metabolites were studied. Our results show that at 400 ppm CO2, wheat plants fertilized with ammonium as the N source had stress symptoms and a strong reduction in stomatal conductance, which negatively affected photosynthetic rates. The higher levels of PIP1.1 and PIP2.3 expression in ammonium-fertilized plants at 400 ppm CO2 might reflect the need to overcome limitations to the CO2 supply to chloroplasts due to restrictions in stomatal conductance. This stomatal limitation might be associated with a strategy to reduce ammonium transport toward leaves. On the other hand, ammonium-fertilized plants at elevated CO2 did not show stress symptoms, and no differences were detected in stomatal opening or water use efficiency (WUE). Moreover, similar gene expression of the aquaporins TIP1, PIP1.1, and PIP2.3 in ammonium-fertilized plants grown at 700 ppm compared to nitrate and ammonium nitrate plants would suggest that an adjustment in CO2 and H2O diffusion is not required. Therefore, in the absence of a stress context triggered by elevated CO2, ammonium- and ammonium nitrate-fertilized plants were able to increase their photosynthetic rates, which were translated eventually into higher leaf protein content

Relationship between tillage management and DMPSA nitrification inhibitor efficiency

Agricultural sustainability is compromised by nitrogen (N) losses caused by soil microbial activity. Nitrous oxide (N2O) is a potent greenhouse gas (GHG) produced as consequence of nitrification and denitrification processes in soils. Nitrification inhibitors (NI) as 3,4-dimethylpyrazole-succinic acid (DMPSA) are useful tools to reduce these N losses from fertilization. The objective of this work was to test the efficiency of DMPSA in two different tillage management systems, conventional tillage (CT) and no-tillage (NT), in a winter wheat crop under Humid Mediterranean conditions. N fertilizer was applied as ammonium sulphate (AS) with or without DMPSA in a single or split application, including an unfertilized treatment. GHG fluxes N2O, CO2 and CH4) were measured by the closed chamber method. amoA and nosZl genes were quantified by qPCR as indicators of nitrifying and denitrifying populations. Nitrification was inhibited by DMPSA in both CT and NT, while the higher water filled pore space (WFPS) in NT promoted a better efficiency of DMPSA in this system. This higher efficiency might be due to a greater N2O reduction to N-2 as result of the nosZl gene induction. Consequently, DMPSA was able to reduce N2O emissions down to the unfertilized levels in NT. Provided that NT reduced CO2 emissions and maintained crop yield compared to CT, the application DMPSA under NT management is a promising strategy to increase agro-systems sustainability under Humid Mediterranean conditions. (C) 2019 The Author(s). Published by Elsevier B.V.This project was funded by de Spanish Government (AGL2015-64582-C3-2-R MINECO/FEDER and RTI2018-094623-B-C21 MCIU/AEI/FEDER, UE), by the Basque Government (IT-932-16) and by EuroChem Agro Iberia S.L.-UPV/EHU 2017.0016. Mario Corrochano-Monsalve held a grant from the Ministry of Economy and Business of the Spanish Government and Ximena Huerfano received a specialization fellowship for PhD researches from the UPV/EHU

Preconcentración por extracción en fase sólida en línea a la electroforesis capilar acoplada a la espectrometría de masas

Los factores más importantes a tener en cuenta cuando se desarrollan nuevas técnicas y métodos de separación son la simplificación, rapidez y coste de los análisis, la reducción de la cantidad de reactivos y muestra necesarias, la mejora de la selectividad, eficacia y resolución de las separaciones, la disminución de los límites de detección y la reproducibilidad de los resultados. En este contexto han ido madurando en los últimos tiempos las técnicas microseparativas, implementándose en microchips o dispositivos microfluídicos o en tubos y columnas capilares [1-6]. Estas técnicas de separación en microescala tienen un gran potencial, porque permiten cumplir prácticamente con todos los requisitos anteriormente indicados. Sin embargo, a menudo los límites de detección (LODs) en unidades de concentración no son lo suficientemente bajos debido a los pequeños volúmenes de muestra necesarios para los análisis con estas técnicas [7-11]. Esto, unido a la siempre cuestionada reproducibilidad, han sido los principales impedimentos para se apliquen ampliamente a muestras complejas reales

Glicoproteínas biomarcadoras de cáncer: un reto analítico actual

Las alteraciones en la glicosilación de las proteínas pueden ser la causa de enfermedades graves, como es el caso de los desórdenes congénitos de la glicosilación (CDGs) o pueden aparecer en respuesta a la presencia de un proceso patológico, como ocurre con el cáncer y los procesos inflamatorios. Por ello, las glicoproteínas se utilizan ampliamente en el diagnóstico de diversas patologías [1, 2]. Por ejemplo, el antígeno carbohidratado 19-9 (CA 19-9), el antígeno carcio-embrionario humano (CEA) o el antígeno prostático específico (PSA) se emplean en la actualidad como biomarcadores para el diagnóstico del cáncer de páncreas, colon o próstata, respectivamente. Sin embargo, sólo se mide el aumento de sus niveles por encima de unos valores establecidos, con lo que en muchos casos estos biomarcadores no son totalmente específicos ya que otras enfermedades pueden presentar niveles anormalmente elevados de estas glicoproteínas. Por este motivo, el reto analítico actual consiste en mejorar la selectividad y la sensibilidad de estos biomarcadores, llevando a cabo una caracterización exhaustiva de los puntos de glicosilación y de la composición y estructura de los carbohidratos, comúnmente llamados glicanos