bluuebunny/crossref_metadata_2025 huggingface dataset:
The Nrf2–ARE Pathway
Authors: Johnson Jeffrey A. , Johnson Delinda A. , Kraft Andrew D. , Calkins Marcus J. , Jakel Rebekah J. , Vargas Marcelo R. , Chen Pei‐Chun
Published: July 2010

Transcriptional activation of protective genes is mediated by a cis‐acting element called the antioxidant responsive element (ARE). The transcription factor Nrf2 (NF–E2‐related factor 2) binds to the ARE. Activation of this pathway protects cells from oxidative stress‐induced cell death. Increased oxidative stress is associated with neuronal cell death during the pathogenesis of multiple chronic neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. We hypothesize that Nrf2–ARE activation is a novel neuroprotective pathway that confers resistance to a variety of oxidative, stress‐related, neurodegenerative insults. In recent studies, primary neuronal cultures treated with chemical activators of the Nrf2–ARE pathway displayed significantly greater resistance to oxidative stress‐induced neurotoxicity. Similar cultures generated from ARE–hPAP reporter mice demonstrated selective activation of the Nrf2–ARE pathway in astrocytes, suggesting that Nrf2 activation in astrocytes somehow confers resistance to naive neurons. Further, in chemical models of neurodegeneration, Nrf2 knockout mice are significantly more sensitive to mitochondrial complex I and II inhibitors. Combining these observations with the results implying that the astrocyte is central to Nrf2–ARE‐mediated neuroprotection, we transplanted Nrf2‐overexpressing astrocytes into the mouse striatum prior to lesioning with malonate. This procedure led to dramatic protection against malonate‐induced neurotoxicity. Translating this to other chemical and genetic models of neurodegeneration will be discussed.
Stressor Specificity of Sex Differences in Hypothalamo-Pituitary-Adrenal Axis Activity: Cortisol Responses to Exercise, Endotoxin, Wetting, and Isolation/Restraint Stress in Gonadectomized Male and Female Sheep
Authors: Turner A. I. , Rivalland E. T. A. , Clarke I. J. , Tilbrook A. J.
Published: July 2010

Sex differences in the stress-induced activity of the hypothalamo-pituitary-adrenal axis in sheep appear to be dependent on the stressor encountered and occur irrespective of the presence of gonadal steroids. We tested the hypotheses that cortisol responses to exercise, endotoxin, wetting (experiment 1), and isolation/restraint (experiment 2) stress differ between gonadectomized male and female sheep. At weekly intervals (in experiment 1), we subjected gonadectomized rams and ewes (n = 6/group) to control conditions, to exercise stress, to iv injection of endotoxin, and to wetting stress. In a second experiment (experiment 2), we subjected gonadectomized rams and ewes (n = 5/group) to control conditions or to isolation/restraint stress. In both experiments, we measured plasma concentrations of cortisol before, during, and after stress at a frequency of at least 15 min with samples collected (from an indwelling jugular catheter) at a greater frequency around the time of the stressor. Cortisol responses to wetting (experiment 1) and isolation/restraint (experiment 2) stress were significantly higher in females compared with males but in response to exercise (experiment 1) and endotoxin (experiment 1) stress, there were no differences between the sexes. For some stressors, there are sex differences in sheep in the stress-induced activity of the hypothalamo-pituitary-adrenal axis that are independent of the presence of the sex steroids, but the existence of these sex differences and the direction of these sex differences differs, depending on the stressor imposed.
Basal Plasma Levels of Insulin, Leptin, Ghrelin, and Amylin Do Not Signal Adiposity in Rats Recovering from Forced Overweight
Authors: Gloy Viktoria L. , Lutz Thomas A. , Langhans Wolfgang , Geary Nori , Hillebrand Jacquelien J.
Published: July 2010

This study examined how adiposity signals are related to adiposity during recovery from forced overweight (OW). Rats were rendered OW by chronic intragastric overfeeding (OW). Overfeeding was stopped when OW rats reached 126–129% of saline-infused normal-weight (NW) rats. Adipose tissue (AT) mass was estimated by computed tomography, and blood was drawn from chronic atrial cannulas throughout. Basal levels (i.e. after 2–3 h fasts late in the diurnal phase) of the hypothesized adiposity signals insulin, leptin, ghrelin, and amylin were assayed. OW rats gained approximately 130 g more body weight (BW) and approximately 100 g more AT mass during overfeeding. Plasma levels of insulin and leptin increased, whereas those of ghrelin decreased, linearly with AT mass; amylin did not change reliably. During recovery, OW rats’ BW and AT mass decreased but were still elevated vs. NW rats after 39 d. OW rats’ insulin returned to NW levels on d 1 of recovery and decreased below NW levels thereafter. Leptin was no longer elevated after d 8 of recovery. Ghrelin and amylin did not change reliably during recovery. Although AT mass decreased in OW rats during each intermeasurement interval between d 0 and d 23 of recovery, insulin and leptin did so during only the first interval (d 0–5). Insulin and leptin levels were exponentially related to AT mass during recovery. These data indicate that basal insulin, leptin, ghrelin, and amylin do not encode AT mass in rats dynamically regulating BW and adiposity during recovery from OW.
Minireview: Early-Life Programming by Inflammation of the Neuroendocrine System
Authors: Kentner A. C. , Pittman Q. J.
Published: July 2010

Acute inflammation results in alterations in both peripheral and central nervous system cytokine levels that together can exert transient but profound alterations in neuroendocrine function. This has been particularly well studied with respect to the hypothalamic-pituitary-adrenal and the hypothalamic-pituitary-gonadal axes. There is now evidence, particularly in rodents, that an inflammation in the neonatal period can have long-term, sex-specific effects on these neuroendocrine axes that persist into adulthood. There are critical time periods for the establishment of these long-term programming effects, and in adulthood they may be revealed either as alterations in basal functioning or in altered responses to a subsequent inflammatory challenge. These studies highlight the importance of early environmental exposure to pathogens in sculpting adult physiology and behavior.
Pph13 and Orthodenticle define a dual regulatory pathway for photoreceptor cell morphogenesis and function
Authors: Mishra Monalisa , Oke Ashwini , Lebel Cindy , McDonald Elizabeth C. , Plummer Zachary , Cook Tiffany A. , Zelhof Andrew C.
Published: July 2010

The function and integrity of photoreceptor cells are dependent upon the creation and maintenance of specialized apical structures: membrane discs/outer segments in vertebrates and rhabdomeres in insects. We performed a molecular and morphological comparison of Drosophila Pph13 and orthodenticle (otd) mutants to investigate the transcriptional network controlling the late stages of rhabdomeric photoreceptor cell development and function. Although Otd and Pph13 have been implicated in rhabdomere morphogenesis, we demonstrate that it is necessary to remove both factors to completely eliminate rhabdomere formation. Rhabdomere absence is not the result of degeneration or a failure of initiation, but rather the inability of the apical membrane to transform and elaborate into a rhabdomere. Transcriptional profiling revealed that Pph13 plays an integral role in promoting rhabdomeric photoreceptor cell function. Pph13 regulates Rh2 and Rh6, and other phototransduction genes, demonstrating that Pph13 and Otd control a distinct subset of Rhodopsin-encoding genes in adult visual systems. Bioinformatic, DNA binding and transcriptional reporter assays showed that Pph13 can bind and activate transcription via a perfect Pax6 homeodomain palindromic binding site and the Rhodopsin core sequence I (RCSI) found upstream of Drosophila Rhodopsin genes. In vivo studies indicate that Pph13 is necessary and sufficient to mediate the expression of a multimerized RCSI reporter, a marker of photoreceptor cell specificity previously suggested to be regulated by Pax6. Our studies define a key transcriptional regulatory pathway that is necessary for late Drosophila photoreceptor development and will serve as a basis for better understanding rhabdomeric photoreceptor cell development and function.
Strigolactones enhance competition between shoot branches by dampening auxin transport
Authors: Crawford Scott , Shinohara Naoki , Sieberer Tobias , Williamson Lisa , George Gilu , Hepworth Jo , Müller Dörte , Domagalska Malgorzata A. , Leyser Ottoline
Published: July 2010

Strigolactones (SLs), or their derivatives, were recently demonstrated to act as endogenous shoot branching inhibitors, but their biosynthesis and mechanism of action are poorly understood. Here we show that the branching phenotype of mutants in the Arabidopsis P450 family member, MAX1, can be fully rescued by strigolactone addition, suggesting that MAX1 acts in SL synthesis. We demonstrate that SLs modulate polar auxin transport to control branching and that both the synthetic SL GR24 and endogenous SL synthesis significantly reduce the basipetal transport of a second branch-regulating hormone, auxin. Importantly, GR24 inhibits branching only in the presence of auxin in the main stem, and enhances competition between two branches on a common stem. Together, these results support two current hypotheses: that auxin moving down the main stem inhibits branch activity by preventing the establishment of auxin transport out of axillary branches; and that SLs act by dampening auxin transport, thus enhancing competition between branches.
Rules, Communication, and Collusion: Narrative Evidence from the Sugar Institute Case
Authors: Genesove David , Mullin Wallace P
Published: July 2010

Detailed notes on weekly meetings of the sugar-refining cartel show how communication helps firms collude, and so highlight the deficiencies in the current formal theory of collusion. The Sugar Institute did not fix prices or output. Prices were increased by homogenizing business practices to make price cutting more transparent. Meetings were used to interpret and adapt the agreement, coordinate on jointly profitable actions, ensure unilateral actions were not misconstrued as cheating, and determine whether cheating had occurred. In contrast to established theories, cheating did occur, but sparked only limited retaliation, partly due to the contractual relations with selling agents. (JEL L13, L41)
Demand Systems With and Without Errors
Authors: Lewbel Arthur
Published: July 2010

Revealed preference theory assumes that each consumer has demands that are rational, meaning that they arise from the maximization of his or her own utility function. In contrast, econometric or statistical demand models assume that each consumer's demands equal a rational systematic component derived from a common utility function, plus an individual-specific, additive error term. This paper reconciles these differences, by providing necessary and sufficient conditions for rationality of statistical demand models given individual consumer rationality. (JEL D11, D12, C30, C43)
Schooling and Labor Market Consequences of School Construction in Indonesia: Evidence from an Unusual Policy Experiment
Authors: Duflo Esther
Published: July 2010

Between 1973 and 1978, the Indonesian government engaged in one of the largest school construction programs on record. Combining differences across regions in the number of schools constructed with differences across cohorts induced by the timing of the program suggests that each primary school constructed per 1,000 children led to an average increase of 0.12 to 0.19 years of education, as well as a 1.5 to 2.7 percent increase in wages. This implies estimates of economic returns to education ranging from 6.8 to 10.6 percent. (JEL I2, J31, O15, O22)
Financing Investment
Authors: Gomes Joao F
Published: July 2010

We examine investment behavior when firms face costs in the access to external funds. We find that despite the existence of liquidity constraints, standard investment regressions predict that cash flow is an important determinant of investment only if one ignores q. Conversely, we also obtain significant cash flow effects even in the absence of financial frictions. These findings provide support to the argument that the success of cash-flow-augmented investment regressions is probably due to a combination of measurement error in q and identification problems. (JEL E22, E44, G31)
Conflicts and Common Interests in Committees
Authors: Li Hao , Rosen Sherwin , Suen Wing
Published: July 2010

Committees improve decisions by pooling members' independent information, but promote manipulation, obfuscation, and exaggeration of private information when members have conflicting preferences. Committee decision procedures transform continuous data into ordered ranks through voting. This coarsens the transmission of information, but controls strategic manipulations and allows some degree of information sharing. Each member becomes more cautious in casting the crucial vote than when he alone makes the decision based on own information. Increased quality of one member's information results in his casting the crucial vote more often. Committees make better decisions for members than does delegation. (JEL D71, D82, C72)
Caecal volvulus: a twisted tale
Authors: Khaniya Sudeep , Shakya Vikal Chandra , Koirala Rabin , Pokharel Krishna , Regmi Rajendra , Adhikary Shailesh , Agrawal Chandra Shekhar
Published: July 2010

Caecal volvulus is an uncommon cause of acute intestinal obstruction caused by axial twisting of the caecum along with the terminal ileum and ascending colon. Early diagnosis is essential in order to reduce the high mortality rate, though the condition is rarely diagnosed correctly at the time of presentation. We report a series of four cases describing their presentation, management and subsequent outcome.
Scrub typhus associated macrophage activation syndrome
Authors: Gopal Gopinath Kango , Anugrah Chrispal , Boorugu Harikishan
Published: July 2010

Macrophage activation syndrome (MAS) is a rare phenomenon that occurs either primarily or secondary to a multitude of conditions, including juvenile rheumatoid arthritis most commonly, and other infections like enteric fever and tuberculosis. It has been reported as an extremely rare complication of scrub typhus with no cases presented from India. We report three cases of scrub typhus presenting with confirmed MAS between January 2007 and December 2007 to a tertiary care hospital in South India. All three patients had clinical and laboratory evidence for scrub typhus and MAS. All the patients responded promptly to antibiotics and made an uneventful recovery. These three patients are presented to highlight the importance of considering scrub typhus in patients with MAS following acute febrile illnesses.
Characterization of EMU, the Arabidopsis homolog of the yeast THO complex member HPR1
Authors: Furumizu Chihiro , Tsukaya Hirokazu , Komeda Yoshibumi
Published: July 2010

Diverse and precise control is essential for eukaryotic gene expression. This is accomplished through the recruitment of a myriad of proteins to a nascent messenger RNA (mRNA) to mediate modifications, such as capping, splicing, 3′-end processing, and export. Despite being important for every cell, however, the mechanism by which the formation of diverse messenger ribonucleoprotein (mRNP) particles contributes to maintaining intricate systems in the multicellular organism remains incompletely defined. We identified and characterized a mutant gene named erecta mRNA under-expressed (emu) that leads to the defective mRNA accumulation of ERECTA, a developmental regulator in the model plant Arabidopsis thaliana. EMU encodes a protein homologous to a component of the THO complex that is required for the generation of functional mRNPs. Further analysis suggested that EMU is genetically associated with SERRATE, HYPONASTIC LEAVES1, and ARGONAUTE1, which are required for proper RNA maturation or action. Furthermore, mutations in another THO-related gene led to embryonic lethality. These findings support the presence and importance of the THO-related complex in plants as well as yeast and vertebrates.
Software Assistants for Randomized Patrol Planning for the LAX Airport Police and the Federal Air Marshal Service
Authors: Jain Manish , Tsai Jason , Pita James , Kiekintveld Christopher , Rathi Shyamsunder , Tambe Milind , Ordóñez Fernando
Published: July 2010

The increasing threat of terrorism makes security at major locations of economic or political importance a major concern. Limited security resources prevent complete security coverage, allowing adversaries to observe and exploit patterns in patrolling or monitoring, and enabling them to plan attacks that avoid existing patrols. The use of randomized security policies that are more difficult for adversaries to predict and exploit can counter their surveillance capabilities. We describe two applications, ARMOR and IRIS, that assist security forces in randomizing their operations. These applications are based on fast algorithms for solving large instances of Bayesian Stackelberg games. Police at the Los Angeles International Airport deploy ARMOR to randomize the placement of checkpoints on roads entering the airport and the routes of canine unit patrols within the airport terminals. The Federal Air Marshal Service has deployed IRIS in a pilot program to randomize the schedules of air marshals on international flights. This paper examines the design choices, information, and evaluation criteria that were critical to developing these applications.
Reactions of aldehydes with chlorous acid and chlorite in chlorine dioxide bleaching
Authors: Lehtimaa Tuula , Kuitunen Susanna , Tarvo Ville , Vuorinen Tapani
Published: July 2010

The role of chlorine (III) compounds, i.e. chlorous acid (HClO2) and chlorite (ClO2
-), in chlorine dioxide bleaching were investigated by treating different pulps with Cl(III). It was discovered that in addition to its fully inorganic reactions, chlorous acid is consumed by organic structures present in the pulp. These structures were assumed to be aldehydes. The aldehydes might exist already in unbleached pulps, but chlorine dioxide bleaching was also found to generate new aldehyde groups. The reactive groups were concluded to originate both from carbohydrates and lignin.
Cure kinetics of PF/PVAc hybrid adhesive for manufacturing profiled wood-strand composites
Authors: Wang Yi , Yadama Vikram , Laborie Marie-Pierre , Bhattacharyya Debes
Published: July 2010

In thermoforming of profiled wood-strand composites, an adhesive system is needed to provide a weak initial bond to maintain mat integrity and architecture during the forming process and eventually a durable bond when the final cross-sectional shape is achieved. A hybrid adhesive composed of phenol formaldehyde (PF) and poly(vinyl acetate) (PVAc) is proposed in this study. The cure kinetics of this hybrid adhesive and bond development in a multi-step hot-pressing is discussed. Cure kinetics studied by differential scanning calorimetry indicated that adding PVAc slowed down the curing reaction of PF resin; however, the full cure of PF was not inhibited. The nth-order Borchardt Daniels (nth-BD) model provided good prediction for the curing of adhesives with a PF/PVAc ratio lower than 1:1. To simulate roll forming of wood-strand mats, a hot-pressing schedule at low temperature combined with multi-stage closing and opening was developed. The nth-BD model was able to predict the actual bond development for composites made with neat PF resin. The results indicated that cure kinetics of a PF/PVAc hybrid adhesive would not significantly differ from neat PF resin for blend ratios of 1:1 or lower, thus potentially providing a resin system for roll forming or matched-die forming of wood-strand composites.
Rheological Characterisation and Empirical Modelling of Lead-Free Solder Pastes and Isotropic Conductive Adhesive Pastes
Authors: Durairaj R. , Man Lam Wai , Ramesh S.
Published: July 2010

Solder pastes and isotropic conductive adhesives (ICAs) are widely used as an interconnect in the electronic industry. Paste printing process accounts for majority of the assembly defects in the electronic manufacturing industry. This study investigates the effect of shear rates on the viscosities of the pastes (solder pastes and ICAs) used for flip chip assembly. Empirical models such as the power law and the Cross model were used to quantify the viscosity over a range of shear rates for solder pastes and fit to the experimental data. The shear rate dependence viscosity of solder pastes could be used to study the flow behavior experienced by the pastes during the stencil printing process. From the results, viscosities of all three types of pastes were said to be dependence on shear rate. In a stencil printing process, as if the viscosity of the solder paste was too high, the paste might not wet the surface of the substrate and more energy was needed to force the paste penetrate the aperture. This study has revealed that the fitting of the Cross model is generally of better quality than the power law model because the qualitative behavior of the Cross model throughout the whole range of shear rates (0.001 s−1 to 100 s−1) is essentially the same as the experimental data.
Encoding and Decoding Cortical Representations of Tactile Features in the Vibrissa System
Authors: Boloori Ali-Reza , Jenks Robert A. , Desbordes Gaëlle , Stanley Garrett B.
Published: July 2010

During behavior, rats and other rodents use their facial vibrissae to actively explore surfaces through whisking and head/body movement, resulting in complex sensory inputs that vary over a large range of angular velocities and temporal scales. How these complex sensory inputs manifest in the patterns of cortical firing events that ultimately form the perceptual experience is not well understood. Through single-unit cortical recordings of layer 4 neurons in S1 of the anesthetized rat, we systematically quantified the interactions between instantaneous velocity and timing of vibrissa motion, finding a strong interaction between angular velocity and timing of contacts on the tens of milliseconds time scale. From the quantification of these joint tuning properties, a detailed nonlinear encoding model was formulated that was highly predictive of firing probability and timing characteristics of the sparse cortical representation of complex patterned tactile inputs. Within a Bayesian framework, the encoding model was then used to decode tactile patterns under simple transformations of the stimulus along dimensions of velocity and timing, as a demonstration of the lower bound of the idealized perceptual capabilities of the animal.
Cell-Mediated Neuroprotection in a Mouse Model of Human Tauopathy
Authors: Hampton David W. , Webber Daniel J. , Bilican Bilada , Goedert Michel , Spillantini Maria Grazia , Chandran Siddharthan
Published: July 2010

Tau protein in a hyperphosphorylated state makes up the intracellular inclusions of several neurodegenerative diseases, including Alzheimer's disease and cases of frontotemporal dementia. Mutations inTaucause familial forms of frontotemporal dementia, establishing that dysfunction of tau protein is sufficient to cause neurodegeneration and dementia. Transgenic mice expressing human mutant tau in neurons exhibit the essential features of tauopathies, including neurodegeneration and abundant filaments composed of hyperphosphorylated tau. Here we show that a previously described mouse line transgenic for human P301S tau exhibits an age-related, layer-specific loss of superficial cortical neurons, similar to what has been observed in human frontotemporal dementias. We also show that focal neural precursor cell implantation, resulting in glial cell differentiation, leads to the sustained rescue of cortical neurons. Together with evidence indicating that astrocyte transplantation may be neuroprotective, our findings suggest a beneficial role for glial cell-based repair in neurodegenerative diseases.
Merlin Inhibits Neurite Outgrowth in the CNS
Authors: Schulz Alexander , Geissler Katja J. , Kumar Sujeet , Leichsenring Gregor , Morrison Helen , Baader Stephan L.
Published: July 2010

The neurofibromatosis type 2 gene product merlin is known to provoke gliogenic tumors as a result of its mutagenic loss. Merlin's physiological anti-mitogenic function makes it unique among its ezrin–radixin–moesin (ERM) family members. Although ERM proteins and merlin are known to be expressed in glial cells of the peripheral nervous system and CNS, the neuronal expression pattern and function of merlin have been less well investigated. We report here expression of merlin in developing and mature neurons of the murine CNS. Within cerebellar Purkinje cells (PCs), merlin was localized in the soma, sprouting dendrites and axons. Merlin expression in PCs was high during the period of initial dendrite regression and declined during later phases of dendrite elongation. Consistently, merlin expressionin vivowas increased in Engrailed-2-overexpressing PCs, which are characterized by a reduced dendritic extension. Furthermore, overexpression of merlin in dissociated cerebellar cultures and in neurogenic P19 cells caused a significant decline in neurite outgrowth, while, conversely, inhibition of merlin expression increased process formation. This effect was dependent on phosphorylation of serine 518 and involved the inactivation of the growth-promoting GTPase Rac. We thus provide evidence that merlin plays a pivotal role in controlling the neuronal wiring in the developing CNS.
Regulation of Opioid Tolerance by let-7 Family MicroRNA Targeting the μ Opioid Receptor
Authors: He Ying , Yang Cheng , Kirkmire Chelsea M. , Wang Zaijie Jim
Published: July 2010

MicroRNA has emerged as a critical regulator of neuronal functions. This study aimed to test whether let-7 microRNAs can regulate the μ opioid receptor (MOR) and opioid tolerance. Employing bioinformatics, we identified a let-7 binding site in the 3′-untranslated region (UTR) of MOR mRNA, which was experimentally confirmed as a direct target of let-7. The repressive regulation of MOR by let-7 was revealed using a LNA-let-7 inhibitor to knockdown let-7 in SH-SY5Y cells. Conversely, morphine significantly upregulated let-7 expression in SH-SY5Y cells and in a mouse model of opioid tolerance. The LNA-let-7 inhibitor decreased brain let-7 levels and partially attenuated opioid antinociceptive tolerance in mice. Although chronic morphine treatment did not change overall MOR transcript, polysome-associated mRNA declined in a let-7-dependent manner. let-7 was identified as a mediator translocating and sequestering MOR mRNA to P-bodies, leading to translation repression. These results suggest that let-7 plays an integral role in opioid tolerance.
Coalescence and Fragmentation of Cortical Networks during Focal Seizures
Authors: Kramer Mark A. , Eden Uri T. , Kolaczyk Eric D. , Zepeda Rodrigo , Eskandar Emad N. , Cash Sydney S.
Published: July 2010

Epileptic seizures reflect a pathological brain state characterized by specific clinical and electrical manifestations. The proposed mechanisms are heterogeneous but united by the supposition that epileptic activity is hypersynchronous across multiple scales, yet principled and quantitative analyses of seizure dynamics across space and throughout the entire ictal period are rare. To more completely explore spatiotemporal interactions during seizures, we examined electrocorticogram data from a population of male and female human patients with epilepsy and from these data constructed dynamic network representations using statistically robust measures. We found that these networks evolved through a distinct topological progression during the seizure. Surprisingly, the overall synchronization changed only weakly, whereas the topology changed dramatically in organization. A large subnetwork dominated the network architecture at seizure onset and preceding termination but, between, fractured into smaller groups. Common network characteristics appeared consistently for a population of subjects, and, for each subject, similar networks appeared from seizure to seizure. These results suggest that, at the macroscopic spatial scale, epilepsy is not so much a manifestation of hypersynchrony but instead of network reorganization.
Fast Sodium Channel Gating Supports Localized and Efficient Axonal Action Potential Initiation
Authors: Schmidt-Hieber Christoph , Bischofberger Josef
Published: July 2010

Action potentials (APs) are initiated in the proximal axon of most neurons. In myelinated axons, a 50-times higher sodium channel density in the initial segment compared to the soma may account for this phenomenon. However, little is known about sodium channel density and gating in proximal unmyelinated axons. To study the mechanisms underlying AP initiation in unmyelinated hippocampal mossy fibers of adult mice, we recorded sodium currents in axonal and somatic membrane patches. We demonstrate that sodium channel density in the proximal axon is ∼5 times higher than in the soma. Furthermore, sodium channel activation and inactivation are ∼2 times faster. Modeling revealed that the fast activation localized the initiation site to the proximal axon even upon strong synaptic stimulation, while fast inactivation contributed to energy-efficient membrane charging during APs. Thus, sodium channel gating and density in unmyelinated mossy fiber axons appear to be specialized for robust AP initiation and propagation with minimal current flow.
Controle de plantas daninhas na cultura de soja resistente ao glyphosate
Authors: Correia Núbia Maria , Durigan Julio Cezar
Published: July 2010

O objetivo da pesquisa foi avaliar o controle de plantas daninhas em área cultivada com soja resistente ao herbicida glyphosate, sem a utilização de práticas complementares de manejo de plantas daninhas. Foram desenvolvidos experimentos, em condições de campo, nos anos agrícolas 2005/2006 e 2006/2007 em Jaboticabal (SP). Foram avaliadas duas cultivares de soja resistentes ao glyphosate (CD 214 RR e M-SOY 8008 RR), oito tratamentos de herbicidas (glyphosate, em aplicação única, nas doses de 0,48; 0,72; 0,96 e 1,20 kg ha-1 de equivalente ácido, associadas ou não a aplicação sequencial na dose de 0,48 kg ha-1), além de duas testemunhas, uma capinada e outra mantida infestada. As cultivares de soja influenciaram na infestação das espécies de plantas daninhas na área. Sem a aplicação de glyphosate, houve o predomínio de X. strumarium na área, desfavorecendo a ocorrência de outras espécies. Quando utilizado glyphosate, independentemente da dose, a infestação contabilizada aos 35 e 40 dias após a primeira aplicação, no primeiro e segundo ano, respectivamente, foi baixa. O controle de plantas daninhas na cultura da soja transgênica é diretamente influenciado pela dose de glyphosate, havendo controle satisfatório com a aplicação única de 0,96 kg ha-1 ou a sequencial de 0,48 + 0,48 kg ha-1 de glyphosate. Em situação de menor infestação (2006/2007), a aplicação única de 0,48 kg ha-1 de glyphosate é suficiente para o controle das plantas daninhas. As cultivares de soja transgênica CD 214 RR e M-SOY 8008 RR influenciam diferencialmente a dinâmica das espécies de plantas daninhas, sendo o controle químico mais efetivo na situação de cultivo de M-SOY 8008 RR, em que houve menor diversidade e desenvolvimento das plantas daninhas.
Conteúdos de biologia em vestibulares seriados
Authors: Manzano Maíra Elias , Lopes Sonia Bueno Carvalho
Published: July 2010

A adoção de novos processos seletivos para o acesso de alunos às universidades só foi possível com a promulgação da Lei de Diretrizes e Bases da Educação Nacional n. 9.394/96. O vestibular seriado é uma dessas propostas alternativas, que prevê uma avaliação sistemática dos alunos ao término de cada ano do ensino médio. O propósito deste estudo foi caracterizar o vestibular seriado, hoje presente em 22 instituições públicas, quanto ao seu objetivo, estilos de avaliação e conteúdos da disciplina de Biologia distribuídos nos módulos referentes às três séries do ensino médio. Averiguamos que os diferentes programas analisados não apresentam uniformidade em diversos aspectos, tais como número de vagas, estrutura de avaliação e conteúdo programático. Verificamos, ainda, a ausência de consenso sobre a sequência a ser adotada para o ensino de Biologia e a resultante restrição para que o aluno possa preparar-se para as provas seriadas em mais de uma instituição.
Comparação de técnicas analíticas para a extração de potássio de amostras de tecido vegetal com água e soluções ácidas concentrada e diluída
Authors: Bernardi Alberto C. C. , Oka Sílvia Harumi , Souza Gilberto B. de
Published: July 2010

O aprimoramento dos métodos analíticos faz com que a busca por novas tecnologias rápidas, exatas e de custo reduzido estejam constantemente sendo revistas e avaliadas. O objetivo deste trabalho foi comparar três formas de extração de K (decomposição nítro-perclórica, extração com água e extração com solução diluída de HCl) de amostras da parte aérea de capim-tanzânia (Panicum maximum cv. Tanzânia) e de alfafa (Medicago sativa cv. Crioula). Os métodos de extração de K de amostras de tecido vegetal de capim-tanzânia e alfafa com solução ácida diluída ou com água apresentaram-se equivalentes ao método tradicional da decomposição nítro-perclórica e podem substituí-lo.
Differentiation of Colletotrichum gloeosporioides isolates by using total proteins and esterase electrophoretic patterns and extracellular enzymes production
Authors: Assis Tereza Cristina de , Menezes Maria , Andrade Domingos Eduardo Guimarães Tavares de , Coelho Rildo Sartori Barbosa
Published: July 2010

Isolates of Colletotrichum gloeosporioides (ISO-1, ISO-2, ISO-3, ISO-4, ISO-5 and ISO-6), the causal agent of anthracnose disease on mango fruits, were characterized by electrophoretic patterns of total proteins and esterase in polyacrylamida gel, and also, by production of extracellular enzymes on specific solid substrate. The electrophoretic analysis showed variation in number, intensity of coloration and position of the bands in the gel at each studied system tested. In contrast to the monomorphic behavior to total proteins, high esterase polymorfism was observed indicating difference among isolates. All isolates showed the activity of extracellular enzymes such as amylase, lipase, and protease with some variation among them. The proteolitic activity seemed to be more accentuated than the two other enzymes studied.
Primeiro relato do Tomato spotted wilt virus (TSWV) em Campanula medium L. no Brasil
Authors: Gioria Ricardo , Brunelli Kátia Regiane , Kobori Romulo Fujito , Kobori Márcia Maria Rabelo Guimarães , Rezende Jorge Alberto Marques , Kitajima Elliot Watanabe
Published: July 2010

Plantas de campânula (Campanula medium) exibindo mosaico e necrose foliar e anéis em flores foram coletadas em uma estufa comercial de flores na região de Atibaia, SP. Suspeitando de possível etiologia viral, amostras de tecido lesionado foram analisadas por ensaios de transmissão mecânica, microscopia eletrônica e sorologia. Todos os resultados apontaram para a presença do Tomato spotted wilt virus (TSWV) como o responsável pelos sintomas. Esse é o primeiro relato deste patógeno em campânula no Brasil.
Efeito da irrigação sobre o potencial fisiológico de sementes de soja em semeadura de inverno
Authors: Silva Josué Bispo da , Lazarini Edson , Sá Marco Eustáquio de , Vieira Roberval Daiton
Published: July 2010

Período seco e temperaturas amenas são condições climáticas ideais durante a maturação e colheita de sementes de soja. O objetivo foi verificar o efeito da irrigação no período pós-maturidade fisiológica, sobre o potencial fisiológico de sementes de soja semeadas no inverno. A disposição dos tratamentos seguiu esquema fatorial envolvendo três cultivares (IAC-19, Conquista e IAC 8-2) e duas épocas de interrupção da irrigação (início do estádio R7 e irrigação até 14 dias após R8). Foram feitas amostragens (colheitas) no início do estádio R7, 3, 7, 10, 14 (estádio R8) e 28 dias após o início do estádio R7. Para as avaliações utilizaram-se os testes de germinação, de envelhecimento acelerado e de condutividade elétrica e determinou-se a porcentagem de sementes manchadas e defeituosas. Nas condições em que foi realizado o experimento, concluiu-se que a irrigação após o estádio R7 não compromete e pode até melhorar o potencial fisiológico das sementes produzidas; a produção de sementes de soja em semeadura de inverno é possível em função de condições climáticas favoráveis.
Qualidade fisiológica de sementes de soja tratadas com inseticidas sob efeito do armazenamento
Authors: Dan Lilian Gomes de Moraes , Dan Hugo de Almeida , Barroso Alberto Leão de Lemos , Braccini Alessandro de Lucca e
Published: July 2010

Dentre os conceitos modernos de controle de pragas, o uso de inseticidas no tratamento de sementes constitui-se num dos métodos mais eficientes. Deve-se, entretanto, conhecer a influência desses produtos com relação à qualidade fisiológica das sementes tratadas. Objetivou-se através desta pesquisa avaliar a qualidade fisiológica de sementes de soja tratadas com inseticidas, sob quatro períodos de armazenamento (0, 15, 30 e 45 dias após o tratamento). O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 4 x 7, com quatro repetições, onde as sementes do cultivar M-SOY 6101 foram tratadas com os inseticidas thiamethoxam (Cruiser 700 WS), na dose de 250 mL de produto comercial (p.c.)/100 kg de sementes; fipronil (Standak), na dose de 150 mL de p.c./100 kg de sementes; imidacloprid (Gaucho FS), na dose de 150 ml de p.c./100 kg de sementes; [imidacloprid + thiodicarb] (CropStar FS), na dose de 0,3 L. ha-1; carbofuran (Furadan 350 TS), na dose de 1,5 L/100 kg de sementes; acefato (Orthene 750 BR), na dose de 1 kg/ 100 kg de sementes e uma testemunha, sem tratamento. As variáveis analisadas foram: germinação, velocidade de emergência, comprimento de raiz e de plântula e porcentagem de plântulas normais no teste de envelhecimento acelerado. A aplicação dos inseticidas carbofuran e acefato é prejudicial à qualidade fisiológica das sementes de soja cultivar M-SOY 6101, por um período de armazenamento de até 45 dias. A redução da qualidade fisiológica das sementes, condicionada pelos inseticidas avaliados, intensifica-se com o prolongamento do armazenamento das sementes tratadas, recomendando-se, portanto, que o tratamento inseticida das sementes seja realizado próximo ao momento da semeadura.
Contrato e confederação: notas sobre o papel das relações internacionais no pensamento político de Jean-Jacques Rousseau
Authors: Marques José Oscar de Almeida
Published: July 2010

Ao ler o Contrato social de Rousseau, tendemos a nos concentrar em seu objetivo explícito, que é o de investigar e estabelecer uma regra de administração legítima e segura para uma comunidade política individual. Em conformidade com o próprio caráter abstrato da obra, somos levados a ver essa comunidade como alguma coisa pré-existente e isolada, sem perguntar o que já havia inicialmente de comum a esses indivíduos que decidem submeter-se à regra de sua vontade geral, e como esse corpo político assim constituído se relaciona com os que não são eles mesmos, mas "os outros", isto é, com as demais sociedades com as quais terá inevitavelmente de conviver. Tais questões tinham grande importância para Rousseau, e só o caráter fragmentário e inconcluso do Contrato social explica por que não receberam o tratamento aprofundado que lhes seria devido. Pretendo, em minha exposição, explorar alguns aspectos das soluções que Rousseau deixou esboçadas em outras obras, especialmente no Emílio e em seu Extrato e Julgamento, do projeto de paz perpétua do Abbé de Saint-Pierre, e que apontam para uma compreensão muito lúcida do problema das relações entre as nações, e para uma solução que tem, surpreendentemente, muito em comum com a que propôs, no Contrato social, para a questão das relações entre indivíduos. Pretendo mostrar que há, em Rousseau, o gérmen de uma concepção das relações internacionais que não as reduz ao mero jogo de forças proposto pelo "realismo" hobbesiano e, ao mesmo tempo, viabiliza a convivência civilizada e regulada, sem impor a uniformidade de valores e perspectivas característica do cosmopolitismo kantiano.
Dissimilaridade genética entre acessos de pimenta com potencial ornamental
Authors: Neitzke Raquel Silviana , Barbieri Rosa Lía , Rodrigues Walter F , Corrêa Inez V , Carvalho Fernando IF de
Published: July 2010

Alguns tipos de pimentas do gênero Capsicum são utilizados como plantas ornamentais, por possuírem caracteres, que conferem valor estético, por serem de fácil cultivo e apresentarem grande durabilidade. Entretanto, no Brasil são poucas as variedades comerciais destinadas a este propósito. O presente trabalho teve por objetivo caracterizar e estudar a distância genética dos acessos com potencial ornamental do Banco Ativo de Germoplasma de Capsicum da Embrapa Clima Temperado. O experimento foi realizado de julho de 2007 a fevereiro de 2008, no campo experimental da Embrapa Clima Temperado, em blocos ao acaso, com três repetições, utilizando 17 acessos, com dez plantas por parcela. As plantas foram caracterizadas morfologicamente com oito descritores quantitativos e 22 descritores qualitativos. Foram realizadas análises de comparação de médias, variáveis canônicas, agrupamento pelo método UPGMA e de Tocher, para os dados quantitativos, e agrupamento pelo método UPGMA e de Tocher para os dados qualitativos. Os acessos foram agrupados de forma distinta quando utilizado dados quantitativos e dados qualitativos. A análise dos dados qualitativos separa mais os acessos, com a formação de maior número de grupos do que na análise dos dados quantitativos. A utilização conjunta da caracterização baseada em descritores quantitativos e qualitativos, porém com análises separadas, possibilita uma interpretação mais fidedigna da dissimilaridade genética e permite o melhor direcionamento dos cruzamentos em Capsicum.
Profilaxia das úlceras associadas ao estresse
Authors: Pompilio Carlos Eduardo , Cecconello Ivan
Published: July 2010

INTRODUÇÃO: As úlceras da mucosa gastroduodenal que aparecem após graves insultos têm sido chamadas de úlceras associadas ao estresse ou, mais genericamente, de "doença mucosa associada ao estresse" (DMAE). São conhecidas desde a Antiguidade e apesar de relacionarem-se com altos índices de morbidade e mortalidade, esquemas de profilaxia no intuito de minimizar seus riscos, só foram introduzidos recentemente. Os inibidores da bomba de prótons têm desempenhado papel importante nesse cenário. MÉTODOS: O presente artigo é uma breve revisão sobre seu uso dentro do contexto clínico da profilaxia do sangramento gastrointestinal relacionado ao estresse.
Potencial genético da população de milho UFV 7 para o melhoramento em Minas Gerais
Authors: Faluba Joyce de Souza , Miranda Glauco Vieira , DeLima Rodrigo Oliveira , Souza Leandro Vagno de , Debem Enoch Assis , Oliveira Ana Maria Cruz e
Published: July 2010

Neste trabalho, objetivou-se avaliar o potencial genético da população de milho UFV 7 para o melhoramento em Minas Gerais. Foram instalados três experimentos com a população de milho UFV 7, em três regiões de Minas Gerais, na safra 2006/2007. Houve interação genótipos x ambientes para todos os caracteres. Foi verificada variabilidade genética para produtividade de grãos, altura de plantas e altura de espigas na população de milho UFV 7, nas três regiões. Na região Sudeste, a população de milho UFV 7 apresentou as maiores estimativas de parâmetros genéticos. A população UFV 7 apresentou alta produtividade de grãos, 9 112kg ha-1, no Sudeste, média produtividade, 6 510kg ha-1, no Oeste, e baixa, 4 572kg ha-1, na região Central. As estimativas de herdabilidade e CVg/CVe, para produtividade, foram superiores a 60% e 1,00, respectivamente. A produtividade de grãos teve correlação genética significativa e positiva com a altura de planta e altura de espiga, na região Oeste e na Central, e com a prolificidade na região Central e região Sudeste. Conclui-se que a população de milho UFV 7 apresenta potencial para extração de linhagens na região Central; potencial para uso imediato na região Sudeste e para novos ciclos de seleção na região Oeste de Minas Gerais, e a seleção para PG aumenta indiretamente a altura de planta e altura de espiga, nas regiões Oeste e Central.
Diversidade genética entre acessos de pimentas e pimentões da Embrapa Clima Temperado
Authors: Büttow Miriam Valli , Barbieri Rosa Lía , Neitzke Raquel Silviana , Heiden Gustavo , Carvalho Fernando Irajá Félix de
Published: July 2010

Os acessos de pimentas e pimentões (Capsicum annuum L.) da Embrapa Clima Temperado constituem parte dos recursos genéticos de Capsicum. Contudo, é necessário conhecer o quanto esses genótipos são divergentes para que possam ser utilizados em programas de melhoramento. Os objetivos deste trabalho foram avaliar e caracterizar a divergência genética entre os acessos de C. annuum do banco ativo de germoplasma de Capsicum da Embrapa Clima Temperado. Foram caracterizados 20 acessos com base em 36 descritores morfológicos multicategóricos. A diversidade genética foi avaliada por meio do método de agrupamento de Tocher e UPGMA. O método de Tocher formou três grupos de acessos. Pelos critérios utilizados, os dois métodos foram concordantes em agrupar isoladamente o acesso P77, que apresenta caracteres morfológicos particulares em relação aos demais. O estudo realizado evidencia a existência de variabilidade genética moderada entre os 20 acessos de C. annuum estudados e apresenta acessos com características ornamentais, os quais podem ser incorporados em programas de melhoramento.
Expressão de Cyr61 em glândulas mamárias normais e neoplásicas de cadelas
Authors: Miguel Marina Pacheco , Sales Tatyane Penha , Menezes Liliana Borges de , Moraes Júlia Miranda , Moura Veridiana Maria Brianezi Dignani de , Brito Luiz Augusto Batista , Araújo Eugênio Gonçalves de
Published: July 2010

As neoplasias mamárias são as mais frequentes em cadelas, representando 25 a 30% do total das afecções neoplásicas das fêmeas caninas. Durante a carcinogênese ocorrem várias modificações na expressão de proteínas, como a Cyr61, envolvida na proliferação celular e na angiogênese. Assim, este estudo teve por objetivo determinar o perfil de expressão dessa proteína, por meio da técnica de imunoistoquímica, em glândulas mamárias normais e neoplásicas de cadelas. Para tal, foram selecionados 10 casos de cada um dos diagnósticos: adenoma simples, carcinoma complexo e carcinoma simples sólido, além de 10 fragmentos de glândulas mamárias normais, perfazendo o total de 40 fragmentos. O anticorpo policlonal anti-Cyr61 apresentou marcação em células epiteliais mamárias normais, evidenciando seu papel nos mecanismos de apoptose e proliferação celular. Houve ainda acentuada imunomarcação em tecidos mamários normais e com adenomas, e marcação discreta em carcinomas, diferente do padrão de expressão observado no tecido mamário de mulheres. A expressão constitutiva da proteína Cyr61 foi demonstrada no tecido mamário canino, constituindo uma alternativa de investigação neoplásica para as alterações mamárias de cadelas.