116 research outputs found

    Doing Collaborative Community Based Research: On the Ground in Kingston

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    Backlash Against Employment Equity: The British Columbia Experience

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    Employment equity policy in the province of British Columbia has undergone a corrosive, back door backlash, compared to Ontario's more classic, or front door, backlash under a similar neoliberal government shift. Using interviews and policy analysis, we document the process. Understanding local variations in the backlash phenomenon is important to strategies to combat oppression and systemic discrimination.La politique sur l'équité en matière d'emploi de la Colombie Britannique a passé par un contre-coup de derrière corrosif, comparée à la politique plus classique de l'Ontario, ou le contre-coup de devant sous un changement de régime néolibéral similaire. En nous servant d'entrevues et d'analyse de politique, nous documentons ce processus. Comprendre les variations locales du phénomène de contre-coup est important aux stratégies pour combattre l'oppression et la discrimination systémique

    Histone methylation by SETD1A protects nascent DNA through the nucleosome chaperone activity of FANCD2

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    Components of the Fanconi anemia and homologous recombination pathways play a vital role in protecting newly replicated DNA from uncontrolled nucleolytic degradation, safeguarding genome stability. Here we report that histone methylation by the lysine methyltransferase SETD1A is crucial for protecting stalled replication forks from deleterious resection. Depletion of SETD1A sensitizes cells to replication stress and leads to uncontrolled DNA2-dependent resection of damaged replication forks. The ability of SETD1A to prevent degradation of these structures is mediated by its ability to catalyze methylation on Lys4 of histone H3 (H3K4) at replication forks, which enhances FANCD2-dependent histone chaperone activity. Suppressing H3K4 methylation or expression of a chaperone-defective FANCD2 mutant leads to loss of RAD51 nucleofilament stability and severe nucleolytic degradation of replication forks. Our work identifies epigenetic modification and histone mobility as critical regulatory mechanisms in maintaining genome stability by restraining nucleases from irreparably damaging stalled replication forks

    PERFIL MICROBIOLÓGICO E QUÍMICO DE EXTRATOS PADRONIZADOS DE INGA MARGINATA

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    Doenças infecciosas vêm apresentando crescente mortalidade no mundo, para o tratamento destas enfermidades as plantas se destacam por apresentar diversas espécies que atuam como agentes terapêuticos. Inga marginata Willd está classificado entre as dez espécies de plantas mais importantes da região do médio Tibagi do estado do Paraná. De acordo com alguns autores a atividade antimicrobiana de folhas de Inga marginata revela um potencial uso desta planta frente a alguns patógenos humanos. Mas devido à carência de uma avaliação mais precisa da espécie, surgiu à necessidade de um estudo, visando elucidar algumas propriedades químicas e microbiológicas desta planta. Com este trabalho foi possível obter informações sobre as melhores condições de extração dos compostos de interesse da planta por meio de um modelo de misturas, determinar o teor de compostos fenólicos totais e avaliar a atividade antimicrobiana da planta contra bacterias Gram positivas e negativas como S. aureus, S. epidermidis, E. coli e P. aeruginosa, como também para fungos como Candida albicans, C. tropicalis and C. glabrata. Com os resultados se constatou que os extratos 1 e 2 extraídos com somente água e etanol, respectivamente, demonstraram efeito bacteriostático contra os microorganismos testados. Isso demonstra uma potencial atividade antibacteriana dos extratos, podendo ser aplicados em formulações farmacêuticas com finalidade antisséptica. Desta forma, a espécie pesquisada pode ser uma alternativa promissora para substituição dos antissépticos usuais de origem sintética por antissépticos de origem natural com menor toxicidade para o ser humano e meio ambiente

    Teaching the history of geography:Current challenges and future directions

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    Drawing upon the personal reflections of geographical educators in Brazil, Canada, the UK, and the US, this Forum provides a state-of-the-discipline review of teaching in the history of geography; identifies the practical and pedagogical challenges associated with that teaching; and offers suggestions and provocations as to future innovation. The Forum shows how teaching in the history of geography is valued – as a tool of identity making, as a device for cohort building and professionalization, and as a means of interrogating the disciplinary present – but also how it is challenged by neoliberal educational policies, competing priorities in curriculum design, and sub-disciplinary divisions

    Modeling the vacuolar storage of malate shed lights on pre- and post-harvest fruit acidity

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    Background: Malate is one of the most important organic acids in many fruits and its concentration plays a critical role in organoleptic properties. Several studies suggest that malate accumulation in fruit cells is controlled at the level of vacuolar storage. However, the regulation of vacuolar malate storage throughout fruit development, and the origins of the phenotypic variability of the malate concentration within fruit species remain to be clarified. In the present study, we adapted the mechanistic model of vacuolar storage proposed by Lobit et al. in order to study the accumulation of malate in pre and postharvest fruits. The main adaptation concerned the variation of the free energy of ATP hydrolysis during fruit development. Banana fruit was taken as a reference because it has the particularity of having separate growth and post-harvest ripening stages, during which malate concentration undergoes substantial changes. Moreover, the concentration of malate in banana pulp varies greatly among cultivars which make possible to use the model as a tool to analyze the genotypic variability. The model was calibrated and validated using data sets from three cultivars with contrasting malate accumulation, grown under different fruit loads and potassium supplies, and harvested at different stages. Results: The model predicted the pre and post-harvest dynamics of malate concentration with fairly good accuracy for the three cultivars (mean RRMSE = 0.25-0.42). The sensitivity of the model to parameters and input variables was analyzed. According to the model, vacuolar composition, in particular potassium and organic acid concentrations, had an important effect on malate accumulation. The model suggested that rising temperatures depressed malate accumulation. The model also helped distinguish differences in malate concentration among the three cultivars and between the pre and post-harvest stages by highlighting the probable importance of proton pump activity and particularly of the free energy of ATP hydrolysis and vacuolar pH. Conclusions: This model appears to be an interesting tool to study malate accumulation in pre and postharvest fruits and to get insights into the ecophysiological determinants of fruit acidity, and thus may be useful for fruit quality improvement. (Résumé d'auteur

    A multi-scale analysis of bull sperm methylome revealed both species peculiarities and conserved tissue-specific

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    peer-reviewedBackground: Spermatozoa have a remarkable epigenome in line with their degree of specialization, their unique nature and different requirements for successful fertilization. Accordingly, perturbations in the establishment of DNA methylation patterns during male germ cell differentiation have been associated with infertility in several species.Background: Spermatozoa have a remarkable epigenResults: The quantification of DNA methylation at CCGG sites using luminometric methylation assay (LUMA) highlighted the undermethylation of bull sperm compared to the sperm of rams, stallions, mice, goats and men. Total blood cells displayed a similarly high level of methylation in bulls and rams, suggesting that undermethylation of the bovine genome was specific to sperm. Annotation of CCGG sites in different species revealed no striking bias in the distribution of genome features targeted by LUMA that could explain undermethylation of bull sperm. To map DNA methylation at a genome-wide scale, bull sperm was compared with bovine liver, fibroblasts and monocytes using reduced representation bisulfite sequencing (RRBS) and immunoprecipitation of methylated DNA followed by microarray hybridization (MeDIP-chip). These two methods exhibited differences in terms of genome coverage, and consistently, two independent sets of sequences differentially methylated in sperm and somatic cells were identified for RRBS and MeDIP-chip. Remarkably, in the two sets most of the differentially methylated sequences were hypomethylated in sperm. In agreement with previous studies in other species, the sequences that were specifically hypomethylated in bull sperm targeted processes relevant to the germline differentiation program (piRNA metabolism, meiosis, spermatogenesis) and sperm functions (cell adhesion, fertilization), as well as satellites and rDNA repeats. Conclusions: These results highlight the undermethylation of bull spermatozoa when compared with both bovine somatic cells and the sperm of other mammals, and raise questions regarding the dynamics of DNA methylation in bovine male germline. Whether sperm undermethylation has potential interactions with structural variation in the cattle genome may deserve further attention. While bull semen is widely used in artificial insemination, the literature describing DNA methylation in bull spermatozoa is still scarce. The purpose of this study was therefore to characterize the bull sperm methylome relative to both bovine somatic cells and the sperm of other mammals through a multiscale analysis
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