252 research outputs found

    Characterization of Shewanella oneidensis MtrC: a cell-surface decaheme cytochrome involved in respiratory electron transport to extracellular electron acceptors

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    MtrC is a decaheme c-type cytochrome associated with the outer cell membrane of Fe(III)-respiring species of the Shewanella genus. It is proposed to play a role in anaerobic respiration by mediating electron transfer to extracellular mineral oxides that can serve as terminal electron acceptors. The present work presents the first spectropotentiometric and voltammetric characterization of MtrC, using protein purified from Shewanella oneidensis MR-1. Potentiometric titrations, monitored by UV–vis absorption and electron paramagnetic resonance (EPR) spectroscopy, reveal that the hemes within MtrC titrate over a broad potential range spanning between approximately +100 and approximately -500 mV (vs. the standard hydrogen electrode). Across this potential window the UV–vis absorption spectra are characteristic of low-spin c-type hemes and the EPR spectra reveal broad, complex features that suggest the presence of magnetically spin-coupled low-spin c-hemes. Non-catalytic protein film voltammetry of MtrC demonstrates reversible electrochemistry over a potential window similar to that disclosed spectroscopically. The voltammetry also allows definition of kinetic properties of MtrC in direct electron exchange with a solid electrode surface and during reduction of a model Fe(III) substrate. Taken together, the data provide quantitative information on the potential domain in which MtrC can operate

    The Present and Future Role of Insect-Resistant Genetically Modified Maize in IPM

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    Commercial, genetically-modified (GM) maize was first planted in the United States (USA, 1996) and Canada (1997) but now is grown in 13 countries on a total of over 35 million hectares (\u3e24% of area worldwide). The first GM maize plants produced a Cry protein derived from the soil bacteriumBacillus thuringiensis (Bt), which made them resistant to European corn borer and other lepidopteran maize pests. New GM maize hybrids not only have resistance to lepidopteran pests but some have resistance to coleopteran pests and tolerance to specific herbicides. Growers are attracted to the Btmaize hybrids for their convenience and because of yield protection, reduced need for chemical insecticides, and improved grain quality. Yet, most growers worldwide still rely on traditional integrated pest management (IPM) methods to control maize pests. They must weigh the appeal of buying insect protection “in the bag” against questions regarding economics, environmental safety, and insect resistance management (IRM). Traditional management of maize insects and the opportunities and challenges presented by GM maize are considered as they relate to current and future insect-resistant products. Four countries, two that currently have commercialize Bt maize (USA and Spain) and two that do not (China and Kenya), are highlighted. As with other insect management tactics (e.g., insecticide use or tillage), GM maize should not be considered inherently compatible or incompatible with IPM. Rather, the effect of GM insect-resistance on maize IPM likely depends on how the technology is developed and used

    Resuscitation Endpoints in Trauma

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    Fluid and blood resuscitation is the mainstay of therapy for the treatment of hemorrhagic shock, whether due to trauma or other etiology. Cessation of hemorrhage with rapid hemostatic techniques is the first priority in the treatment of traumatic hemorrhagic shock, with concomitant fluid resuscitation with blood and crystalloids to maintain perfusion and organ function. “Hypotensive” or “low-volume” resuscitation has become increasingly accepted in the prehospital resuscitation phase of trauma, prior to definitive hemorrhage control, since aggressive fluid resuscitation may increase bleeding. Resuscitation after hemorrhage control is focused on restoration of tissue oxygenation. Efforts to optimize resuscitation have used “resuscitation endpoints” as markers of adequacy of resuscitation. The resuscitation endpoints that have been evaluated include both global (restoration of blood pressure, heart rate and urine output, lactate, base deficit, mixed venous oxygen saturation, ventricular end-diastolic volume) and regional (gastric tonometry, near-infrared spectroscopy for measurement of muscle tissue oxygen saturation) measures. This review critically evaluates the evidence regarding the use of resuscitation endpoints in trauma.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75386/1/j.1778-428X.2005.tb00127.x.pd

    In-hospital mortality and the Glasgow Coma Scale in the first 72 hours after traumatic brain injury

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    This study verifies and compares the performance of three different scores obtained in the Glasgow Coma Scale (GCS) in the first 72 hours post trauma in predicting in-hospital mortality. The studied scores included those obtained after initial care was provided at the hospital, and the worst and best scores obtained in the scale in the first 72 hours post trauma. The scale’s predictive ability was assessed by the Receiver Operator Characteristic (ROC) curve. A total of 277 victims with different severity levels of blunt traumatic brain injuries were studied. The performance of the three scores that were analyzed to predict hospital mortality was moderate (0.74 to 0.79) and the areas under the curve did not present statistically significant differences. These findings suggest that any of the three studied scores can be applied in clinical practice to estimate the outcome of victims with blunt traumatic brain injuries, taking into consideration the instrument’s moderate discriminatory power.El estudio tiene como objetivos verificar y comparar el desempeño de puntajes de la Escala de Coma de Glasgow (ECGl) observados en las primeras 72 horas postrauma para predecir la mortalidad hospitalaria. Los valores analizados fueron los puntajes obtenidos después de la atención inicial intra-hospitalaria, además de los peores y mejores resultados de la escala en las primeras 72 horas postrauma. La capacidad de predicción de los puntajes de la ECGl para el Estado Vital a la Salida Hospitalaria fue evaluada, utilizando la curva Reciever Operator Characteristic. Fueron estudiadas 277 víctimas, con trauma encefalocraneano contuso de diferentes gravedades. El desempeño de los puntajes de la ECGl para el estado vital a la salida hospitalaria fue moderado (0,74 a 0,79) y las áreas bajo la curva no presentaron diferencia significativa. Los resultados sugieren que cualquiera de los tres valores de la ECGl analizados pueden ser aplicados en la práctica clínica para estimar el pronóstico de las víctimas de trauma encefalocraneano contuso, considerando, sin embargo su moderado poder discriminatorio.O estudo teve como objetivos verificar e comparar o desempenho de escores da Escala de Coma de Glasgow (ECGl) observados nas primeiras 72 horas após trauma, para predizer mortalidade hospitalar. Os valores analisados foram os escores obtidos após atendimento inicial intra-hospitalar, além dos piores e melhores resultados da escala nas primeiras 72 horas pós-trauma. A capacidade preditiva dos escores da ECGl para estado vital à saída hospitalar foi avaliada, utilizando-se a curva Reciever Operator Characteristic. Foram estudadas 277 vítimas, com trauma cranioencefálico contuso de diferentes gravidades. O desempenho dos escores da ECGl para estado vital à saída hospitalar foi moderado (0,74 a 0,79) e as áreas sob a curva não apresentaram diferença significativa. Os resultados sugerem que qualquer um dos três valores da ECGl analisados podem ser aplicados na prática clínica para estimar o prognóstico das vitimas de trauma cranioencefálico contuso, considerando-se, no entanto, seu moderado poder discriminatório

    Zebrafish arl6ip1 Is Required for Neural Crest Development during Embryogenesis

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    BACKGROUND:Although the embryonic expression pattern of ADP ribosylation factor-like 6 interacting protein 1 (Arl6ip1) has been reported, its function in neural crest development is unclear. METHODS/PRINCIPAL FINDINGS:We found that knockdown of Arl6ip1 caused defective embryonic neural crest derivatives that were particularly severe in craniofacial cartilages. Expressions of the ectodermal patterning factors msxb, dlx3b, and pax3 were normal, but the expressions of the neural crest specifier genes foxd3, snai1b, and sox10 were greatly reduced. These findings suggest that arl6ip1 is essential for specification of neural crest derivatives, but not neural crest induction. Furthermore, we revealed that the streams of crestin- and sox10-expressing neural crest cells, which migrate ventrally from neural tube into trunk, were disrupted in arl6ip1 morphants. This migration defect was not only in the trunk neural crest, but also in the enteric tract where the vagal-derived neural crest cells failed to populate the enteric nervous system. We found that this migration defect was induced by dampened Shh signaling, which may have resulted from defective cilia. These data further suggested that arl6ip1 is required for neural crest migration. Finally, by double-staining of TUNEL and crestin, we confirmed that the loss of neural crest cells could not be attributed to apoptosis. CONCLUSIONS/SIGNIFICANCE:Therefore, we concluded that arl6ip1 is required for neural crest migration and sublineage specification

    Organoids as a Model for Intestinal Ion Transport Physiology

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    The advent of intestinal organoid culture in 2009 was a fortuitous development in the search for a valid marker of intestinal stem cells, and provided proof of murine intestinal stem cell regenerative potential. Intestinal organoid culture was preceded by key discoveries of the Wnt/β-catenin signaling pathway and the development of 3D culture matrices. The latter, involving a laminin-rich gel to provide an artificial basement membrane, was instrumental to primary intestinal epithelial culture by preventing anoikis, an immediate apoptotic event when intestinal epithelial cells detach from the basement membrane. One of the first physiological studies using 3D murine “mini-gut” structures showed cystic fibrosis transmembrane conductance regulator (CFTR) expression and anion channel activity in the crypt-like structures projecting from the epithelial-lined central cavity. Detailed investigations of ion transport physiology using human intestinal organoids, both primary and iPSC-derived, found close similarities to existing knowledge of ion transport physiology and included the development of the forskolin-induced swelling assay (FIS). The FIS assay using organoids cultured from rectal biopsies of cystic fibrosis patients provided an avenue for personalized medicine to test small-molecule modulators on different CFTR mutations. More recent research has led to the development of 2D primary intestinal epithelial monolayers, which provide easy access to the apical, lumen-facing membrane and the opportunity for traditional ion transport studies with Ussing chambers. Human 2D primary intestinal monolayers also demonstrate the dominance of CFTR in anion secretion and provide a quantitative evaluation of its chloride and bicarbonate secretory conductances. These aspects of ion transport physiology using 2D and 3D intestinal cultures are discussed along with the relative advantages and disadvantages of each culture method with respect to technical aspects and recapitulation of native intestinal epithelium

    Justice from an interdisciplinary perspective: the impact of the revolution in Human Sciences on Peace Research and International Relations

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    Peace and justice have been a preferred couple in theoretical writings - but what do we know about their empirical relationship? Insights from other disciplines suggest that humans are highly sensitive to violations of justice and that justice concerns permeate social relations. Neuroscientists have located the parts of the brain responsible for negative reactions to violation of claims for justice. Evolutionary biologists have identified rules of distribution and retribution not only in early human societies but among other socially living species as well. Psychologists have observed the emergence of a sense of justice in very early childhood, while behavioral economists have identified behavior of average persons in experiments that deviated significantly from the model of the "economic man" and could only be explained by a sense of justice. The chapter summarizes these findings and outlines their implications for peace research. It highlights the ambivalent nature of justice for social relations. Justice concerns can exacerbate conflicts between individuals and groups but justice can also provide standards for arriving at durable peaceful solutions to conflicts. Understanding these ambivalences and their repercussions for international and intrastate relations provides a promising path towards understanding conflict dynamics
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