Recursos de colección

Archivo Digital UPM (107.543 recursos)

This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Materia = Biología

Mostrando recursos 1 - 20 de 805

  1. Arabidopsis NITRILASE 1 contributes to the regulation of root growth and development through modulation of auxin biosynthesis in seedlings

    Lehmann, Thomas; Janowitz, TiM; Sánchez Parra, Beatriz; Pérez Alonso, Marta Marina; Trompetter, Inga; Piotrowski, Markus; Pollmann, Stephan
    Nitrilases consist of a group of enzymes that catalyze the hydrolysis of organic cyanides. They are found ubiquitously distributed in the plant kingdom. Plant nitrilases are mainly involved in the detoxification of ß-cyanoalanine, a side-product of ethylene biosynthesis. In the model plant Arabidopsis thaliana a second group of Brassicaceae-specific nitrilases (NIT1-3) has been found. This so-called NIT1-subfamily has been associated with the conversion of indole-3-acetonitrile (IAN) into the major plant growth hormone, indole-3-acetic acid (IAA). However, apart of reported functions in defense responses to pathogens and in responses to sulfur depletion, conclusive insight into the general physiological function of the...

  2. An Ethylene-Protected Achilles' Heel of Etiolated Seedlings for Arthropod Deterrence

    Boex-Fontvieille, Edouard; Rustgi, Sachin; Von Wettstein, Diter; Pollmann, Stephan; Reinbothe, Steffen; Reinbothe, Christiane
    A small family of Kunitz protease inhibitors exists in Arabidopsis thaliana, a member of which (encoded by At1g72290) accomplishes highly specific roles during plant development. Arabidopsis Kunitz-protease inhibitor 1 (Kunitz-PI;1), as we dubbed this protein here, is operative as cysteine PI. Activity measurements revealed that despite the presence of the conserved Kunitz-motif the bacterially expressed Kunitz-PI;1 was unable to inhibit serine proteases such as trypsin and chymotrypsin, but very efficiently inhibited the cysteine protease RESPONSIVE TO DESICCATION 21. Western blotting and cytolocalization studies using mono-specific antibodies recalled Kunitz-PI;1 protein expression in flowers, young siliques and etiolated seedlings. In dark-grown seedlings,...

  3. The N-end rule pathway regulates pathogen responses in plants

    De Marchi, Rémi; Sorel, Maud; Mooney, Brian; Fudal, Isabelle; Goslin, Kevin; Kwasniewska, Kamila; Ryan, Patrick T.; Pfalz, Marina; Kroymann, Juergen; Pollmann, Stephan; Feechan, Angela; Wellmer, Frank; Rivas, Susana; Graciet, Emmanuelle
    To efficiently counteract pathogens, plants rely on a complex set of immune responses that are tightly regulated to allow the timely activation, appropriate duration and adequate amplitude of defense programs. The coordination of the plant immune response is known to require the activity of the ubiquitin/proteasome system, which controls the stability of proteins in eukaryotes. Here, we demonstrate that the N-end rule pathway, a subset of the ubiquitin/proteasome system, regulates the defense against a wide range of bacterial and fungal pathogens in the model plant Arabidopsis thaliana. We show that this pathway positively regulates the biosynthesis of plant-defense metabolites such...

  4. Programmed chloroplast destruction during leaf senescence involves 13-lipoxygenase (13-LOX)

    Springer, Armin; Kang, Chulhee; Rustgi, Sachin; Von Wettstein, Diter; Reinbothe, Christiane; Pollmann, Stephan; Reinbothe, Steffen
    Mammals including humans use highly specific pathways for tissue differentiation. One such pathway is operative in reticulocytes and involves the programmed destruction of the cell?s organellar complement by 15-lipoxygenase (15-LOX), which oxygenates polyunsaturated membrane fatty acids and provokes organelle leakage. As we report here, plants make use of a similar LOX pathway to degrade their chloroplasts during leaf senescence. The enzyme involved is a 13-LOX with unique positional specificity and molecular terms. Because 15-LOX and 13-LOX pathway products likewise operate in biological defense, a mechanism of cross-kingdom conservation of pathway regulation and function was uncovered for multicellular eukaryotes.

  5. Impacto del cambio climático sobre los ecosistemas fluviales

    Santiago Saez, Jose Maria
    La temperatura del agua es de interés central en ecología del medio fluvial, ya que esta influye sobre los procesos físicos, químicos y biológicos que se producen en los ríos y, consecuentemente, sobre los organismos que en ellos desarrollan su vida o parte de ella. El régimen térmico de los ríos es un factor de gran importancia en la definición y determinación del estado de los ecosistemas acuáticos, teniendo una gran influencia en el éxito biológico de los peces. La temperatura atmosférica ha registrado una tendencia ascendente durante el pasado siglo XX, siendo especialmente patente esta tendencia desde la década...

  6. New patterns in human biogeography revealed by networks of contacts between linguistic groups

    Capitán Gómez, José Ángel; Axelsen, Jakob Bock; Manrubia, Susanna
    Human languages differ broadly in abundance and are distributed highly unevenly on the Earth. In many qualitative and quantitative aspects, they strongly resemble biodiversity distributions. An intriguing and previously unexplored issue is the architecture of the neighbouring relationships between human linguistic groups. Here we construct and characterize these networks of contacts and show that they represent a new kind of spatial network with uncommon structural properties. Remarkably, language networks share a meaningful property with food webs: both are quasi-interval graphs. In food webs, intervality is linked to the existence of a niche space of low dimensionality; in language networks, we...

  7. Effects of Previous Land-Use on Plant Species Composition and Diversity in Mediterranean Forests.

    Kouba, Yacine; Martinez Garcia, Felipe; Frutos, Angel de; Alados, Concepcion
    Se estudia el efecto del aprovechamiento tradicionales en bosque de quejidos en el prepirineo aragonés sobre la composición y diversidad de especies en la actualidad.Bosque

  8. Stem girdling evidences a trade-off between cambial activity and sprouting and dramatically reduces plant transpiration due to feedback inhibition of photosynthesis and hormone signaling.

    López Rodríguez, Rosa Ana; Brossa, Ricard; Gil Sanchez, Luis Alfonso; Pita Andreu, Pilar
    The photosynthesis source-sink relationship in young Pinus canariensis seedlings was modified by stem girdling to investigate sprouting and cambial activity, feedback inhibition of photosynthesis, and stem and root hydraulic capacity. Removal of bark tissue showed a trade-off between sprouting and diameter growth. Above the girdle, growth was accelerated but the number of sprouts was almost negligible, whereas below the girdle the response was reversed. Girdling resulted in a sharp decrease in whole plant transpiration and root hydraulic conductance. The reduction of leaf area after girdling was strengthened by the high levels of abscisic acid found in buds which pointed to...

  9. Stream flow regime, temperature and climate change: the loss of fish habitat

    Santiago Saez, Jose Maria; Solana Gutierrez, Joaquin; Alonso González, Carlos; García de Jalón Lastra, Diego; Muñoz-Mas, Rafael; Martínez-Capel, Francisco; Ribalaygua Batalla, Jaime; Pórtoles, Javier; Monjo, Robert
    This study is aimed at forecasting the changes in the suitability of brown trout habitat (Salmo trutta L.), caused by alterations in the stream temperature and the flow regime under climate change scenarios. The stream temperature and instantaneous flow in several streams in Central Spain were modelled from daily temperature and precipitation data. Logistic models were used for stream temperature modelling whereas M5? model trees were used to develop the precipitation-runoff models. These models were utilized to simulate the running flows under the climate change scenarios RCP4.5 and RCP8.5 (5thIPCC). The resulting forecasts suggested a different response of the stream...

  10. A study of seed micromorphology in the genus Ophrys (Orchidaceae)

    Galán Cela, Pablo; Seligrat, Irene; Ortuñez, Emma; Gamarra, Roberto; Vivar Sanz, Alejandro; Scrugli, Antonio
    Seed micromorphology of 19 taxa of the genus Ophrys have been studied using SEM and light microscope. Quantitative data (length and width of seed and embryo, number of testa cells along the longitudinal axis, volume of seed and embryo, and percentage of free air space), as well as qualitative characters (seed shape, features of the anticlinal and periclinal walls, ornamentation and colour) were analysed. All the seeds are fusiform, with an asymmetrical basal pole, the periclinal walls of the medial cells have parallel and transverse to slanting ridges, and raised anticlinal walls. Statistical analyses show two large clusters according to the...

  11. How similar can co-occurring species be in the presence of competition and ecological drift?

    Capitán Gómez, José Ángel; Cuenda, Sara; Alonso Giménez, David
    If two species live on a single resource, the one with a slight advantage will out-compete the other: complete competitors cannot coexist. This is known as the competitive exclusion principle. If no extinction occurs, it is because evolutionary adaptation to slightly different niches takes place. Therefore, it is widely accepted that ecological communities are assembled by evolutionary differentiation and progressive adaptation of species to different niches. However, some ecologists have recently challenged this classic paradigm highlighting the importance of chance and stochasticity. Using a synthetic framework for community dynamics, here we show that, while deterministic descriptors predict coexistence, species similarity...

  12. Engineering nitrogen-fixing plants: multigene transfer, targeting of expression to organelles and tissues, and other challenges

    Caro Bernat, Elena
    Biological N2 fixation, catalyzed by the prokaryotic enzyme nitrogenase, is an alternative to the use of synthetic N fertilizers to increase cereal production yields. The strategy we are pursuing in an effort to increase cereal crops productivity is the direct transfer of nif prokaryotic genes into cereals. Because Nitrogenase is an O2-labile metalloenzyme which biosynthesis requires a complex pathway where numerous nif gene products are involved, the main challenges we face are the control of gene expression and protein accumulation in an O2 depleted environment and the stable and high expression of multiple transgenes. Our efforts are now focused on...

  13. Population genomics of the legume plant host specific selection of rhizobial genotypes

    Jorrin Rubio, Beatriz; Imperial Ródenas, Juan
    Rhizobium leguminosarum bv. viciae (Rlv) establish effective symbioses with four legume genera: Pisum, Lens, Lathyrus and Vicia. Classic studies using trap plants provided evidence that, given a choice, specific hosts select specific genotypes of rhizobia which are, apparently, particularly adapted to that host (Mutch & Young, 2004; Louvrier et al, 1996). OBJETIVE Pooled DNA samples from Rlv nodule isolates obtained from different legume plant hosts used as rhizobial traps should allow a test of the hypothesis that different plant hosts select specific subpopulations of rhizobia from the available population present in a given soil. MATERIALS AND METHODS We have applied...

  14. Role of poplar DNA demethylases in controlling winter dormancy

    Conde Rodriguez, Daniel; Moreno Cortés, Alicia; Hernández Verdeja, Tamara; Ramos Sanchez, Jose Manuel; Perales, Mariano; González Melendi, Pablo; Allona Alberich, Isabel Marta
    Trees have developed the mechanism of winter dormancy to survive the harsh conditions of winter in temperate and cold regions. It determines the geographical distribution of tree species and the long of the growing period. Epigenetic control of winter dormancy in woody plants is barely known. 5-methyl cytosine (5mC) is an important epigenetic mark that regulates gene expression in animals and plants. The profile of DNA methylation changes in the transition of developmental stages in plants such as chestnut bud set and burst, flowering in azalea, aging in pine trees among other. So far, the enzymes involved in the modification...

  15. Biomecánica de árboles: morfología de un haya (Fagus sylvatica L.) singular del Hayedo de Montejo de la Sierra y modelo mecánico mediante tecnología LiDAR terrestre

    Crespo Suárez, Cristina
    El presente proyecto tiene como objetivo analizar estructuralmente el tronco de un haya singular del Hayedo de Montejo, ubicado en la sierra de Madrid, con la característica particular del empleo de tecnología LiDAR (Laser Imaging Detection and Ranging) terrestre. El Hayedo de Montejo es conocido a nivel nacional e internacional, acoge hayas centenarias y singulares a una latitud meridional y poco frecuente en esta especie. La densidad en la actualidad es tan elevada, que existe una fuerte competencia entre el arbolado, sumada a las severas cortas de ramas para la tradicional obtención de leñas (que han dado lugar a pudriciones internas),...

  16. Biocircuits engineering and bio-design automation: some recent results

    Rodríguez-Patón Aradas, Alfonso

  17. BactoSim - an individual-based simulation environment for bacterial conjugation

    Prestes García, Antonio; Rodríguez-Patón Aradas, Alfonso
    BactoSim is an agent-based platform for simulating the con- jugation in spatially structured bacterial populations, which are the con- ditions typically found on naturally occurring colonies such as biofilms or in agar-based laboratory cultures. The model provides a set of key indicators which can be visualized in real time as the simulation evolves and saved as for further analysis.

  18. Variabilidad ambiental y productividad en Pinus halepensis Mill.

    García Fernández, Pablo
    El pino carrasco (Pinus halepensis Mill.) es una especie de gran importancia en restauraciones y repoblaciones en la península Ibérica, capaz de subsistir en zonas secas y ambientes desfavorables, y crucial en el estudio del cambio climático al situarse en un enclave tan representativo como la cuenca mediterránea. A pesar de ello, es muy poca la información que se tiene sobre el comportamiento de esta especie. Por este motivo en el presente trabajo se ha estudiado la productividad del pino carrasco -a través del índice de sitio-, y su relación con la variabilidad climática y edáfica de distintos lugares de España...

  19. Origen, dispersión y diversidad del chirimoyo (Annona cherimola Mill.) en el continente americano

    Larrañaga González, Nerea
    En este trabajo se ha profundizado en las razones que pueden explicar la distribución actual de la diversidad genética del chirimoyo (Annona cherimola Mill.), una especie frutal adaptada a climas subtropicales, con claras implicaciones para su uso y conservación. Gracias a un estudio de código de barras, se pudo comprobar el poder de discriminación del gen cloroplastídico maturasa K (matK) entre las especies con mayor importancia agronómica del género. Además, sobre los polimorfismos de nucleótido único (SNPs) interespecíficos, se diseñaron marcadores que permitieron la identificación mediante presencia o ausencia de bandas en geles de electroforesis de dichas especies tras PCR....

  20. Towards understanding RAV1 transcriptional network during the growth-dormancy cycle in poplar

    Triozzi, Paolo M.; Ramos Sanchez, Jose Manuel; Moreno Cortés, Alicia; Conde Rodriguez, Daniel; González Melendi, Pablo; Allona Alberich, Isabel Marta; Perales, Mariano
    As plants are sessile organisms, the decision to grow or to stop growing is fundamental for their survival. To survive to the harsh condition of the winter, temperate and boreal trees undergo a self-protective developmental reprograming known as winter dormancy. Its mechanism involves an intricate interplay between endogenous growth regulators and the winter external signal, such as shortening of photoperiod and cold temperatures. Currently, only few factors including circadian and developmental transcription factors and hormonal signaling molecules have been shown to modulate the extension of the dormancy period in woody plants. In our laboratory, the circadian controlled transcription factor RAV...

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