Signaling in plants

Higher plants are sessile organisms that perceive environmental cues such as light and chemical signals and respond by changing their morphologies. Signaling pathways utilize a complex network of interactions to orchestrate biochemical and physiological responses such as flowering, fruit ripening, germination, photosynthetic regulation, and shoot or root development. In this session, the mechanisms of signaling systems that trigger plant responses to light and to the gaseous hormone, ethylene, were discussed. These signals are first sensed by a receptor and transmitted to the nucleus by a complex network. A signal may be transmitted to the nucleus by any of several systems including GTP binding proteins (G proteins), which change activity upon GTP binding; protein kinase cascades, which sequentially phosphorylate and activate a series of proteins; and membrane ion channels, which change ionic characteristics of the cells. The signal is manifested in the nucleus as a change in the activity of DNA-binding proteins, which are transcription factors that specifically interact and modulate the regulatory regions of genes. Thus, detection of an environmental signal is transmitted through a transduction pathway, and changes in transcription factor activity may coordinate changes in the expression of a portfolio of genes to direct new developmental programs.

Ribonucleoprotein infrastructure regulating the flow of genetic information between the genome and the proteome

Following transcription and splicing, each mRNA of a mammalian cell passes into the cytoplasm where its fate is in the hands of a complex network of ribonucleoproteins (mRNPs). The success or failure of a gene to be expressed depends on the performance of this mRNP infrastructure. The entry, gating, processing, and transit of each mRNA through an mRNP network helps determine the composition of a cell's proteome. The machinery that regulates storage, turnover, and translational activation of mRNAs is not well understood, in part, because of the heterogeneous nature of mRNPs. Recently, subsets of cellular mRNAs clustered as members of mRNP complexes have been identified by using antibodies reactive with RNA-binding proteins, including ELAV/Hu, eIF-4E, and poly(A)-binding proteins. Cytoplasmic ELAV/Hu proteins are involved in the stability and translation of early response gene (ERG) transcripts and are expressed predominately in neurons. mRNAs recovered from ELAV/Hu mRNP complexes were found to have similar sequence elements, suggesting a common structural linkage among them. This approach opens the possibility of identifying transcripts physically clustered in vivo that may have similar fates or functions. Moreover, the proteins encoded by physically organized mRNAs may participate in the same biological process or structural outcome, not unlike operons and their polycistronic mRNAs do in prokaryotic organisms. Our goal is to understand the organization and flow of genetic information on an integrative systems level by analyzing the collective properties of proteins and mRNAs associated with mRNPs in vivo.

From seed germination to flowering, light controls plant development via the pigment phytochrome.

Plant growth and development are regulated by interactions between the environment and endogenous developmental programs. Of the various environmental factors controlling plant development, light plays an especially important role, in photosynthesis, in seasonal and diurnal time sensing, and as a cue for altering developmental pattern. Recently, several laboratories have devised a variety of genetic screens using Arabidopsis thaliana to dissect the signal transduction pathways of the various photoreceptor systems. Genetic analysis demonstrates that light responses are not simply endpoints of linear signal transduction pathways but are the result of the integration of information from a variety of photoreceptors through a complex network of interacting signaling components. These signaling components include the red/far-red light receptors, phytochromes, at least one blue light receptor, and negative regulatory genes (DET, COP, and FUS) that act downstream from the photoreceptors in the nucleus. In addition, a steroid hormone, brassinolide, also plays a role in light-regulated development and gene expression in Arabidopsis. These molecular and genetic data are allowing us to construct models of the mechanisms by which light controls development and gene expression in Arabidopsis. In the future, this knowledge can be used as a framework for understanding how all land plants respond to changes in their environment.

Study of interaction between Si(O,C) nanowires and the biological system

Nanomedicine is a new branch of medicine, based on the potentiality and intrinsic properties of nanomaterials. Indeed, the nanomaterials ( i.e. the materials with nano and under micron size) can be suitable to different applications in biomedicine. The nanostructures can be used by taking advantage of their properties (for example superparamagnetic nanoparticles) or functionalized to deliver the drug in a specific target, thanks the ability to cross biological barriers. The size and the shape of 1D-nanostructures (nanotubes and nanowires) have an important role on the cell fate: their morphology plays a key role on the interaction between nanostructure and the biological system. For this reason the 1D nanostructure are interesting for their ability to mime the biological system. An implantable material or device must therefore integrate with the surrounding extracellular matrix (ECM), a complex network of proteins with structural and signaling properties. Innovative techniques allow the generation of complex surface patterns that can resemble the structure of the ECM, such as 1D nanostructures. NWs based on cubic silicon carbide (3C-SiC), either bare (3C-SiC NWs) or surrounded by an amorphous shell (3C-SiC/SiO2 core/shell NWs), and silicon oxycarbide nanowires (SiOxCy NWs) can meet the chemical, mechanical and electrical requirements for tissue engineering and have a strong potential to pave the way for the development of a novel generation of implantable nano-devices. Silicon oxycarbide shows promising physical and chemical properties as elastic modulus, bending strength and hardness, chemical durability superior to conventional silicate glasses in aggressive environments and high temperature stability up to 1300 °C. Moreover, it can easily be engineered through functionalization and decoration with macro-molecules and nanoparticles. Silicon carbide has been extensively studied for applications in harsh conditions, as chemical environment, high electric field and high and low temperature, owing to its high hardness, high thermal conductivity, chemical inertness and high electron mobility. Also, its cubic polytype (3C) is highly biocompatible and hemocompatible, and some prototypes of biomedical applications and biomedical devices have been already realized starting from 3C-SiC thin films. Cubic SiC-based NWs can be used as a biomimetic biomaterial, providing a robust and novel biocompatible biological interface . We cultured in vitro A549 human lung adenocarcinoma epithelial cells and L929 murine fibroblast cells over core/shell SiC/SiO2, SiOxCy and bare 3C-SiC nanowire platforms, and analysed the cytotoxicity, by indirect and direct contact tests, the cell adhesion, and the cell proliferation. These studies showed that all the nanowires are biocompatible according to ISO 10993 standards. We evaluated the blood compatibility through the interaction of the nanowires with platelet rich plasma. The adhesion and activation of platelets on the nanowire bundles, assessed via SEM imaging and soluble P-selectin quantification, indicated that a higher platelet activation is induced by the core/shell structures compared to the bare ones. Further, platelet activation is higher with 3C-SiC/SiO2 NWs and SiOxCyNWs, which therefore appear suitable in view of possible tissue regeneration. On the contrary, bare 3C-SiC NWs show a lower platelet activation and are therefore promising in view of implantable bioelectronics devices, as cardiovascular implantable devices. The NWs properties are suitable to allow the design of a novel subretinal Micro Device (MD). This devices is based on Si NWs and PEDOT:PSS, though the well know principle of the hybrid ordered bulk heterojunction (OBHJ). The aim is to develop a device based on a well-established photovoltaic technology and to adapt this know-how to the prosthetic field. The hybrid OBHJ allows to form a radial p–n junction on a nanowire/organic structure. In addition, the nanowires increase the light absorption by means of light scattering effects: a nanowires based p-n junction increases the light absorption up to the 80%, as previously demonstrated, overcoming the Shockley-Queisser limit of 30 % of a bulk p-n junction. Another interesting employment of these NWs is to design of a SiC based epicardial-interacting patch based on teflon that include SiC nanowires. . Such contact patch can bridge the electric conduction across the cardiac infarct as nanowires can ‘sense’ the direction of the wavefront propagation on the survival cardiac tissue and transmit it to the downstream surivived regions without discontinuity. The SiC NWs are tested in terms of toxicology, biocompatibility and conductance among cardiomyocytes and myofibroblasts.

Azudes y acueductos del sistema de riego tradicional de la Vega Baja del Segura (Alicante, España)

En el presente trabajo se describen y analizan las principales obras hidráulicas del sistema de riego tradicional de la comarca de la Vega Baja del Segura, concretamente, los azudes y los acueductos. Los azudes de toma, construidos en el cauce del río Segura, representan el inicio del sistema, desde donde parte una extensa y compleja red de acueductos constituida por acequias y azarbes, como elementos fundamentales, que distribuyen el agua para el regadío. En este estudio se ha llevado a cabo una amplia y profunda investigación documental, tomado datos de campo y captado imágenes in situ que, junto con los diagramas aportados, resultan imprescindibles para comprender la magnitud del sistema. Los resultados obtenidos han servido no sólo para catalogar y caracterizar los elementos que integran el sistema hidráulico del regadío tradicional de la Vega Baja del Segura, sino también para poner de manifiesto un ejemplo real de optimización de recursos hídricos en una zona del sureste peninsular español de escasa e irregular pluviometría. Asimismo, el estudio efectuado revela un sistema de riego sumamente eficiente desde un punto de vista cuantitativo y no tanto desde el cualitativo, debido a la presencia, entre otros contaminantes, de altas concentraciones de sales.

SCAPHOID AND LUNATE CARPAL MECHANICS OVER THE SPECTRUM OF HEALTHY FUNCTION

When ligaments within the wrist are damaged, the resulting loss in range of motion and grip strength can lead to reduced earning potential and restricted ability to perform important activities of daily living. Left untreated, ligament injuries ultimately lead to arthritis and chronic pain. Surgical repair can mitigate these issues but current procedures are often non-anatomic and unable to completely restore the wrist’s complex network of ligaments. An inability to quantitatively assess wrist function clinically, both before and after surgery, limits the ability to assess the response to clinical intervention. Previous work has shown that bones within the wrist move in a similar pattern across people, but these patterns remain challenging to predict and model. In an effort to quantify and further develop the understanding of normal carpal mechanics, we performed two studies using 3D in vivo carpal bone motion analysis techniques. For the first study, we measured wrist laxity and performed CT scans of the wrist to evaluate 3D carpal bone positions. We found that through mid-range radial-ulnar deviation range of motion the scaphoid and lunate primarily flexed and extended; however, there was a significant relationship between wrist laxity and row-column behaviour. We also found that there was a significant relationship between scaphoid flexion and active radial deviation range of motion. For the second study, an analysis was performed on a publicly available database. We evaluated scapholunate relative motion over a full range of wrist positions, and found that there was a significant amount of variation in the location and orientation of the rotation axis between the two bones. Together the findings from the two studies illustrate the complexity and subject specificity of normal carpal mechanics, and should provide insights that can guide the development of anatomical wrist ligament repair surgeries that restore normal function.

Piecing together evolution of the vertebrate endocrine system

One of the great challenges in biology is to understand how particular complex morphological and physiological characters originated in specific evolutionary lineages. In this article, we address the origin of the vertebrate hypothalamic-pituitary-peripheral gland (H-P-PG) endocrine system, a complex network of specialized tissues, ligands and receptors. Analysis of metazoan nucleotide and protein sequences reveals a patchwork pattern of H-P-PG gene conservation between vertebrates and closely related invertebrates (ascidians). This is consistent with a model of how the vertebrate H-P-PG endocrine system could have emerged in relatively few steps by gene family expansion and by regulatory and structural modifications to genes that are present in a chordate ancestor. Some of these changes might have resulted in new connections between metabolic or signaling pathways, such as the bridging of 'synthesis islands' to form an efficient system for steroid hormone synthesis.

The Rab5 effector rabankyrin-5 regulates and coordinates different endocytic mechanisms

The small GTPase Rab5 is a key regulator of clathrin-mediated endocytosis. On early endosomes, within a spatially restricted domain enriched in phosphatydilinositol-3-phosphate [PI(3)P], Rab5 coordinates a complex network of effectors that functionally cooperate in membrane tethering, fusion, and organelle motility. Here we discovered a novel PI(3)P-binding Rab5 effector, Rabankyrin-5, which localises to early endosomes and stimulates their fusion activity. In addition to early endosomes, however, Rabankyrin-5 localises to large vacuolar structures that correspond to macropinosomes in epithelial cells and fibroblasts. Overexpression of Rabankyrin-5 increases the number of macropinosomes and stimulates fluid-phase uptake, whereas its downregulation inhibits these processes. In polarised epithelial cells, this function is primarily restricted to the apical membrane. Rabankyrin-5 localises to large pinocytic structures underneath the apical surface of kidney proximal tubule cells, and its overexpression in polarised Madin-Darby canine kidney cells stimulates apical but not basolateral, non-clathrin-mediated pinocytosis. in demonstrating a regulatory role in endosome fusion and (macro) pinocytosis, our studies suggest that Rab5 regulates and coordinates different endocytic mechanisms through its effector Rabankyrin-5. Furthermore, its active role in apical pinocytosis in epithelial cells suggests an important function of Rabankyrin-5 in the physiology of polarised cells.

Co-expression of SOX9 and SOX10 during melanocytic differentiation in vitro

Investigations into pigment cell biology have relied on the ability to culture both murine and human melanocytes, numerous melanoma cell lines and more recently, murine and human melanoblasts. Melanoblast culture requires medium supplemented with a range of growth factors including Stem Cell Factor, Endothelin-3 and Fibroblast Growth Factor-2, withdrawal of which causes the cells to differentiate into melanocytes. Using the human melanoblast culture system, we have now examined the expression and/or DNA binding activity of several transcription factors implicated in melanocytic development and differentiation. Of these, the POU domain factor BRN2 and the SOX family member SOX10 are both highly expressed in unpigmented melanocyte precursors but are down-regulated upon differentiation. In contrast, the expression levels of the previously described MITF and PAX3 transcription factors remain relatively constant during the melanoblast-melanocyte transition. Moreover, BRN2 ablated melanoma cells lack expression of SOX10 and MITF but retain PAX3. A novel finding implicates a second SOX protein, SOX9, as a potential melanogenic transcriptional regulator, as its expression level is increased following the down-regulation of BRN2 and SOX10 in differentiated melanoblasts. Our results suggest that a complex network of transcription factor interactions requiring proper temporal coordination is necessary for acquisition and maintenance of the melanocytic phenotype. (c) 2005 Elsevier Inc. All rights reserved.

SARAH POULTON KALLEY (1825-1907): Professora, Missionária e Poetisa

Sarah Poulton Kalley é conhecida, em quase todos os segmentos do protestantismo do Brasil, devido à organização e compilação d e Salmos e Hinos, o mais antigo hinário protestante editado no vernáculo em nosso país. Seus hinos, ainda em uso em muitas igrejas, marcaram por mais de um século a teologia do protestantismo no Brasil. Apesar desta notoriedade, sua influência na gênese do protestantismo brasileiro nunca foi objeto de estudo. Assim, o objetivo desta pesquisa é resgatar e visibilizar áreas e estratégias de atuação que conferem a esta mulher um perfil de atuação relativamente autônomo. Contudo, centrada no estudo da trajetória intelectual e biográfica de um sujeito histórico, a investigação se defronta com um universo de personagens anônimos, envoltos numa complexa teia de relações, através das quais o protestantismo se insere no Brasil em um contexto especifico: huguenotes, puritanos, luddistas, famílias não-conformistas inglesas, líderes políticos e eclesiásticos, exilados madeirenses, brasileiros, portugueses, imigrantes alemães e, principalmente, a mulher protestante brasileira. A busca por informações sobre este universo relegado ao anonimato pela historiografia do protestantismo no Brasil, reve lou alguns documentos inéditos, inclusive um livro escrito por Sarah Poulton Kalley, em 1866: o A Alegria da Casa. Muito além do papel de esposa de um missionário e médico, Sarah Poulton Kalley emerge de uma rede de relações e práticas como professora, missionária e poetisa. Nestes três campos de atuação e através do desenvolvimento de múltiplos contatos e relacionamentos, procurava transformar e influenciar atitudes e crenças de seus interlocutores. Junto com a nova fé divulgava uma cosmovisão própria da cultura anglo-saxã, protestante e puritana, adaptando-a seletivamente ao universo cultural e social de seus interlocutores.(AU)

Case study as a research strategy : investigating extreme weather resilience of construction SMEs in the UK

Determining an appropriate research methodology is considered as an important element in a research study; especially in a doctoral research study. It involves approach to the entire process of a research study, starting from theoretical underpinnings and spanning to data collection and analysis, and extending to developing the solutions for the problems investigated. Research methodology in essence is focused around the problems to be investigated in a research study and therefore varies according to the problems investigated. Thus, identifying the research methodology that best suits a research in hand is important, not only as it will benefit achieving the set objectives of a research, but also as it will serve establishing the credibility of the work. Research philosophy, approach, strategy, choice, and techniques are inherent components of the methodology. Research strategy provides the overall direction of the research including the process by which the research is conducted. Case study, experiment, survey, action research, grounded theory and ethnography are examples for such research strategies. Case study is documented as an empirical inquiry that investigates a contemporary phenomenon within its real-life context, especially when the boundaries between phenomenon and context are not clearly evident. Case study was adopted as the overarching research strategy, in a doctoral study developed to investigate the resilience of construction Small and Medium-sized Enterprises (SMEs) in the UK to extreme weather events. The research sought to investigate how construction SMEs are affected by EWEs, respond to the risk of EWEs, and means of enhancing their resilience to future EWEs. It is argued that utilising case study strategy will benefit the research study, in achieving the set objectives of the research and answering the research questions raised, by comparing and contrasting with the alternative strategies available. It is also claimed that the selected strategy will contribute towards addressing the call for improved methodological pluralism in construction management research, enhancing the understanding of complex network of relationships pertinent to the industry and the phenomenon being studied.

Case study as a research strategy:investigating extreme weather resilience of construction SMEs in the UK

Determining an appropriate research methodology is considered as an important element in a research study; especially in a doctoral research study. It involves approach to the entire process of a research study, starting from theoretical underpinnings and spanning to data collection and analysis, and extending to developing the solutions for the problems investigated. Research methodology in essence is focused around the problems to be investigated in a research study and therefore varies according to the problems investigated. Thus, identifying the research methodology that best suits a research in hand is important, not only as it will benefit achieving the set objectives of a research, but also as it will serve establishing the credibility of the work. Research philosophy, approach, strategy, choice, and techniques are inherent components of the methodology. Research strategy provides the overall direction of the research including the process by which the research is conducted. Case study, experiment, survey, action research, grounded theory and ethnography are examples for such research strategies. Case study is documented as an empirical inquiry that investigates a contemporary phenomenon within its real-life context, especially when the boundaries between phenomenon and context are not clearly evident. Case study was adopted as the overarching research strategy, in a doctoral study developed to investigate the resilience of construction Small and Medium-sized Enterprises (SMEs) in the UK to extreme weather events. The research sought to investigate how construction SMEs are affected by EWEs, respond to the risk of EWEs, and means of enhancing their resilience to future EWEs. It is argued that utilising case study strategy will benefit the research study, in achieving the set objectives of the research and answering the research questions raised, by comparing and contrasting with the alternative strategies available. It is also claimed that the selected strategy will contribute towards addressing the call for improved methodological pluralism in construction management research, enhancing the understanding of complex network of relationships pertinent to the industry and the phenomenon being studied.

Reporting and managing risk:a look at current practice at Tesco, RBS, local and central government

These case studies from CIMA highlight the need to embed risk management within more easily understood behaviours, consistent with the overall organisational culture. In each case, some form of internal audit team provides either an oversight function or acts as an expert link in that feedback loop. Frontline staff, managers and specialists should be completely aligned on risk, in part just to ensure that there is a consistency of approach. They should understand instinctively that good performance includes good risk management. Tesco has continued to thrive during the recession and remains a robust and efficient group of businesses despite the emergence of potential threats around consumer spending and the supply chain. RBS, by contrast, has suffered catastrophic and very public failures of risk management despite a large in-house function and stiff regulation of risk controls. Birmingham City Council, like all local authorities, is adapting to more commercial modes of operation and is facing diverse threats and opportunities emerging as a result of social change. And DCMS, like many other public sector organisations, has to handle an incredibly complex network of delivery partners within the context of a relatively recent overhaul of central government risk management processes. Key Findings: •Risk management is no longer solely a financial discipline, nor is it simply a concern for the internal control function. •Where organisations retain a discrete risk management cadre – often specialists at monitoring and evaluating a range of risks – their success is dependent on embedding risk awareness in the wider culture of the enterprise. •Risk management is most successful when it is explicitly linked to operational performance. •Clear leadership, specific goals, excellent influencing skills and open-mindedness to potential threats and opportunities are essential for effective risk management. •Bureaucratic processes and systems can hamper good risk management – either as a result of a ‘box-ticking mentality’ or because managers and staff believe they do not need to consider risk themselves.

Patronage and bribery in sixteenth-century Peru: The government of Viceroy Conde del Villar and the visita of Licentiate Alonso Fernandez de Bonilla

This dissertation deals with the nature of the political system in sixteenth-century colonial Spanish America through an analysis of the administration of Viceroy Fernando de Torres y Portugal, Conde del Villar, in Peru (1585–1590). The political conflicts surrounding his government and the accusations of bribery leveled against him and members of his household provide the documentation for a case study in a system in which prestige and authority were defined through a complex network of patronage and personal relationships with the Spanish monarch, the ultimate source of legitimate power. ^ This dissertation is conceptualized using categories presented in Max Weber's theory on the nature of political order and authority in the history of human societies and the definition of the patrimonial system as one in which the power of he king confers legitimacy and authority on the whole political structure. ^ The documentary base for this dissertation is an exceptionally detailed and complete record related to the official administrative review ( visita) ordered by Philip II in 1588 to assess the government of Viceroy Torres y Portugal. Additionally, letters as well as other primary and secondary sources are scattered in repositories on both sides of the Atlantic. ^ The study of this particular case offers an excellent opportunity to gain an understanding of a political order in which jurisdictional boundaries between institutions and authorities were not clearly defined. The legal system operating in the viceroyalty was subordinated to the personal decisions of the king, and order and equilibrium were maintained through the interaction of patronage networks that were reproduced at all levels of the colonial society. ^ The final charges against Viceroy Conde del Villar, as well as their impact on the political career of those involved in the accusations, reveal that situations today understood to constitute bribery had a different meaning in the context of a patrimonial order. ^

Estimulação optogenética do septo medial no rato anestesiado e em livre comportamento

Theta rhythm consists of an electrophysiological hippocampal oscillation present in mammalian species (4-12 Hz with variations across species). This oscillation is present during active waking and is also prevalent in local field potentials (LFP) during rapid eye movement sleep (REM sleep). Several studies have shown that theta rhythm is important in cognitive tasks and that the medial septum is a key region for its occurrence. The septum sends cholinergic, GABAergic and glutamatergic projections to the hippocampus, which in turn projects axons to the septum. Besides the septum, other regions are involved in regulating theta rhythm, forming a complex network of interactions among brain areas that result in theta rhythm. Optogenetics is a recently developed method that has been widely used in various research areas. It allows us to manipulate the electrical activity of neurons through light stimulation. One of the existing techniques consists in using a viral vector to induce the neuronal expression of ion channels associated with the light-sensitive molecule rhodopsin (e.g. ChR2). Once infected, the neurons become sensitive to light of a particular wavelength. The present M. Sc. research aimed to perform luminous stimulation of the brain in anesthetized and freely behaving animals using chronically implanted electrodes and optical fibers in animals infected with a viral vector for ChR2 expression. Surgical viral injections were performed in the medial septum; histological results confirmed the expression of ChR2 by way of the presence of the eYFP reporter protein in the septum and also in hippocampal processes. Moreover, we performed acute experiments with luminous stimulation of the medial septum and LFP recordings of the septum and hippocampus of anesthetized animals. Action potentials were recorded in the septum. In these experiments we observed a significant increase in the firing rates of septal neurons during luminous stimulation (n = 300 trials). Furthermore, we found an early light-evoked response in the hippocampal LFP. Chronic experiments with luminous stimulation of the medial septum and hippocampus in freely behaving animals were also performed in combination with LFP recordings. We found that the luminous stimulation of the septum is able to induce theta rhythm in the hippocampus. Together, the results demonstrate that the luminous stimulation of the medial septum in optogenetically-modified animals causes relevant electrophysiological changes in the septum and the hippocampus.