Identificación de complejos organometálicos en tejidos vegetales mediante espectrometría de masas

1 .pdf (32 Pags.) copia de la presentación original del autor en la Jornada.Peer reviewe

Metabolite Profile Changes in Xylem Sap and Leaf Extracts of Strategy I Plants in Response to Iron Deficiency and Resupply

The metabolite profile changes induced by Fe deficiency in leaves and xylem sap of several Strategy I plant species have been characterized. We have confirmed that Fe deficiency causes consistent changes both in the xylem sap and leaf metabolite profiles. The main changes in the xylem sap metabolite profile in response to Fe deficiency include consistent decreases in amino acids, N-related metabolites and carbohydrates, and increases in TCA cycle metabolites. In tomato, Fe resupply causes a transitory flush of xylem sap carboxylates, but within 1 day the metabolite profile of the xylem sap from Fe-deficient plants becomes similar to that of Fe-sufficient controls. The main changes in the metabolite profile of leaf extracts in response to Fe deficiency include consistent increases in amino acids and N-related metabolites, carbohydrates and TCA cycle metabolites. In leaves, selected pairs of amino acids and TCA cycle metabolites show high correlations, with the sign depending of the Fe status. These data suggest that in low photosynthesis, C-starved Fe-deficient plants anaplerotic reactions involving amino acids can be crucial for short-term survival

Changes in the proteomic and metabolic profiles of Beta vulgaris root tips in response to iron deficiency and resupply

<p>Abstract</p> <p>Background</p> <p>Plants grown under iron deficiency show different morphological, biochemical and physiological changes. These changes include, among others, the elicitation of different strategies to improve the acquisition of Fe from the rhizosphere, the adjustment of Fe homeostasis processes and a reorganization of carbohydrate metabolism. The application of modern techniques that allow the simultaneous and untargeted analysis of multiple proteins and metabolites can provide insight into multiple processes taking place in plants under Fe deficiency. The objective of this study was to characterize the changes induced in the root tip proteome and metabolome of sugar beet plants in response to Fe deficiency and resupply.</p> <p>Results</p> <p>Root tip extract proteome maps were obtained by 2-D isoelectric focusing polyacrylamide gel electrophoresis, and approximately 140 spots were detected. Iron deficiency resulted in changes in the relative amounts of 61 polypeptides, and 22 of them were identified by mass spectrometry (MS). Metabolites in root tip extracts were analyzed by gas chromatography-MS, and more than 300 metabolites were resolved. Out of 77 identified metabolites, 26 changed significantly with Fe deficiency. Iron deficiency induced increases in the relative amounts of proteins and metabolites associated to glycolysis, tri-carboxylic acid cycle and anaerobic respiration, confirming previous studies. Furthermore, a protein not present in Fe-sufficient roots, dimethyl-8-ribityllumazine (DMRL) synthase, was present in high amounts in root tips from Fe-deficient sugar beet plants and gene transcript levels were higher in Fe-deficient root tips. Also, a marked increase in the relative amounts of the raffinose family of oligosaccharides (RFOs) was observed in Fe-deficient plants, and a further increase in these compounds occurred upon short term Fe resupply.</p> <p>Conclusions</p> <p>The increases in DMRL synthase and in RFO sugars were the major changes induced by Fe deficiency and resupply in root tips of sugar beet plants. Flavin synthesis could be involved in Fe uptake, whereas RFO sugars could be involved in the alleviation of oxidative stress, C trafficking or cell signalling. Our data also confirm the increase in proteins and metabolites related to carbohydrate metabolism and TCA cycle pathways.</p

Rapid alteration of cellular redox homeostasis upon exposure to cadmium and mercury in alfalfa seedlings.

Summary • Here, the kinetics of oxidative stress responses of alfalfa ( Medicago sativa ) seedlings to cadmium (Cd) and mercury (Hg) (0, 3, 10 and 30 µ M ) exposure, expanding from a few minutes to 24 h, were studied. • Intracellular oxidative stress was analysed using 2 ′ ,7 ′ -dichlorofluorescin diacetate and extracellular hydrogen peroxide (H 2 O 2 ) production was studied with Amplex Red. Growth inhibition, concentrations of ascorbate, glutathione (GSH), homoglutathione (hGSH), Cd and Hg, ascorbate peroxidase (APX) activity, and expression of genes related to GSH metabolism were also determined. • Both Cd and Hg increased cellular reactive oxygen species (ROS) production and extracellular H 2 O 2 formation, but in different ways. The increase was mild and slow with Cd, but more rapid and transient with Hg. Hg treatments also caused a higher cell death rate, significant oxidation of hGSH, as well as increased APX activity and transient overexpression of glutathione reductase 2, glutamylcysteinyl synthetase, and homoglutathione synthetase genes. However, Cd caused minor alterations. Hg accumulation was one order of magnitude higher than Cd accumulation. • The different kinetics of early physiological responses in vivo to Cd and Hg might be relevant to the characterization of their mechanisms of toxicity. Thus, high accumulation of Hg might explain the metabolism poisoning observed in Hg-treated seedlings

Morphological Plant Modeling: Unleashing Geometric and Topological Potential within the Plant Sciences

The geometries and topologies of leaves, flowers, roots, shoots, and their arrangements have fascinated plant biologists and mathematicians alike. As such, plant morphology is inherently mathematical in that it describes plant form and architecture with geometrical and topological techniques. Gaining an understanding of how to modify plant morphology, through molecular biology and breeding, aided by a mathematical perspective, is critical to improving agriculture, and the monitoring of ecosystems is vital to modeling a future with fewer natural resources. In this white paper, we begin with an overview in quantifying the form of plants and mathematical models of patterning in plants. We then explore the fundamental challenges that remain unanswered concerning plant morphology, from the barriers preventing the prediction of phenotype from genotype to modeling the movement of leaves in air streams. We end with a discussion concerning the education of plant morphology synthesizing biological and mathematical approaches and ways to facilitate research advances through outreach, cross-disciplinary training, and open science. Unleashing the potential of geometric and topological approaches in the plant sciences promises to transform our understanding of both plants and mathematics

La espectrometría de masas en el estudio de metales pesados en plantas

1 .pdf (79 Pags.) copia de la presentación original del autor (Conferencia oral).Índice: * Introducción al transporte de metales * Técnicas disponibles,MS * Aplicaciones, estado actual * Homeostasis, proteomica, metabolómicaPeer reviewe

Transporte de hierro a larga distancia y metabolómica de la deficiencia de hierro en plantas = Long distance iron transport and metabolism changes in iron deficient plants

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología. fecha de lectura: 11/2/201

Long distance iron transport and metabolomics of plant iron deficiency

195 Pag.[ES] Los objetivos generales de esta tesis doctoral son: a) desarrollar y aplicar nuevas metodologías analíticas que permitan la especiación química del Fe en los fluidos vegetales involucrados en el transporte a larga distancia de este elemento en plantas y b) estudiar el perfil de metabolitos de plantas cultivadas en condiciones de deficiencia de Fe. Para alcanzar estos objetivos generales se plantean los siguientes objetivos específicos: 1. Estudiar el efecto del pH y las reacciones de intercambio del metal o el ligando sobre la formación de complejos metálicos con nicotianamina mediante espectrometría de masas (MS) con analizador de tiempo de vuelo (TOF) y fuente de electrospray (ESI). 2. Desarrollar un método que permita la determinación de complejos naturales de Fe en plantas involucrados en el transporte de este elemento vía xilema mediante cromatografía líquida de alta resolución (HPLC) acoplada a ESI-TOFMS y espectrometría de masas con fuente de plasma de acoplamiento inductivo (ICP-MS). 3. Desarrollar un método que permita la determinación de ácidos orgánicos en tejidos vegetales mediante HPLC-ES-TOFMS. 4. Caracterizar los cambios en el perfil de metabolitos que se producen en condiciones de deficiencia y reaporte de Fe en las raíces de las plantas mediante cromatografía de gases acoplada a espectrometría de masas (GC-MS). 5. Caracterizar los cambios en el perfil de metabolitos que se producen en condiciones de deficiencia y reaporte de Fe en la savia de xilema y las hojas de las plantas mediante GC-MS.[EN] The general objectives of this Thesis are: i) to develop and apply new analytical methodologies for the determination of the Fe forms involved in long-distance Fe transport in plants, and ii) to study the metabolite profile of plants grown under Fe-deficiency conditions. In order to achieve these general objectives the specific objectives are: 1. To study the formation of metal complexes with nicotianamine as affected by pH, ligand and metal exchange by means of electrospray time-of-flight mass spectrometry (ESI-TOFMS). 2. To develop a method for the determination of naturally occurring Fe complexes in xylem sap, using high performance liquid chromatography coupled to ESI-TOFMS and inductively coupled plasma mass spectrometry (HPLC-ESI-TOFMS and HPLC-ICP-MS, respectively). 3. To develop an HPLC-ESI-TOFMS method for the determination of organic acids in plant tissues. 4. To characterize the changes induced in the metabolite profile of plant roots in response to Fe deficiency and resupply, using gas chromatography coupled to mass spectrometry (GC-MS). 5. To characterize the changes induced in the metabolite profile of xylem sap and leaves of plants in response to Fe deficiency and resupply, using GC-MS.This Thesis was supported by the Spanish MICINN (projects AGL2004- 00194 and AGL2007-61948, co-financed with FEDER), the European Commission (Thematic Priority 5- Food Quality and Safety, 6th Framework RTD Programme, Contract no. FP6- FOOD-CT-2006-016279) and the Aragón Government (group A03). Rubén Rellán Álvarez was supported by a FPI fellowship from the Spanish Ministry of Science and Innovation (MICINN).Peer reviewe