116 research outputs found
Conzen, M.P., ed. (1986) World Patterns of Modern Urban Change : Essays in Honor of Chauncy D. Harris. Chicago, The University of Chicago, Dept. of Geography, Research Papers 217-218, 479 p.
Backlash Against Employment Equity: The British Columbia Experience
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
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
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Prebiotic effects: metabolic and health benefits
The different compartments of the gastrointestinal tract are inhabited by populations of micro-organisms. By far the most important predominant populations are in the colon where a true symbiosis with the host exists that is a key for well-being and health. For such a microbiota, 'normobiosis' characterises a composition of the gut 'ecosystem' in which micro-organisms with potential health benefits predominate in number over potentially harmful ones, in contrast to 'dysbiosis', in which one or a few potentially harmful micro-organisms are dominant, thus creating a disease-prone situation. The present document has been written by a group of both academic and industry experts (in the ILSI Europe Prebiotic Expert Group and Prebiotic Task Force, respectively). It does not aim to propose a new definition of a prebiotic nor to identify which food products are classified as prebiotic but rather to validate and expand the original idea of the prebiotic concept (that can be translated in 'prebiotic effects'), defined as: 'The selective stimulation of growth and/or activity(ies) of one or a limited number of microbial genus(era)/species in the gut microbiota that confer(s) health benefits to the host.' Thanks to the methodological and fundamental research of microbiologists, immense progress has very recently been made in our understanding of the gut microbiota. A large number of human intervention studies have been performed that have demonstrated that dietary consumption of certain food products can result in statistically significant changes in the composition of the gut microbiota in line with the prebiotic concept. Thus the prebiotic effect is now a well-established scientific fact. The more data are accumulating, the more it will be recognised that such changes in the microbiota's composition, especially increase in bifidobacteria, can be regarded as a marker of intestinal health. The review is divided in chapters that cover the major areas of nutrition research where a prebiotic effect has tentatively been investigated for potential health benefits. The prebiotic effect has been shown to associate with modulation of biomarkers and activity(ies) of the immune system. Confirming the studies in adults, it has been demonstrated that, in infant nutrition, the prebiotic effect includes a significant change of gut microbiota composition, especially an increase of faecal concentrations of bifidobacteria. This concomitantly improves stool quality (pH, SCFA, frequency and consistency), reduces the risk of gastroenteritis and infections, improves general well-being and reduces the incidence of allergic symptoms such as atopic eczema. Changes in the gut microbiota composition are classically considered as one of the many factors involved in the pathogenesis of either inflammatory bowel disease or irritable bowel syndrome. The use of particular food products with a prebiotic effect has thus been tested in clinical trials with the objective to improve the clinical activity and well-being of patients with such disorders. Promising beneficial effects have been demonstrated in some preliminary studies, including changes in gut microbiota composition (especially increase in bifidobacteria concentration). Often associated with toxic load and/or miscellaneous risk factors, colon cancer is another pathology for which a possible role of gut microbiota composition has been hypothesised. Numerous experimental studies have reported reduction in incidence of tumours and cancers after feeding specific food products with a prebiotic effect. Some of these studies (including one human trial) have also reported that, in such conditions, gut microbiota composition was modified (especially due to increased concentration of bifidobacteria). Dietary intake of particular food products with a prebiotic effect has been shown, especially in adolescents, but also tentatively in postmenopausal women, to increase Ca absorption as well as bone Ca accretion and bone mineral density. Recent data, both from experimental models and from human studies, support the beneficial effects of particular food products with prebiotic properties on energy homaeostasis, satiety regulation and body weight gain. Together, with data in obese animals and patients, these studies support the hypothesis that gut microbiota composition (especially the number of bifidobacteria) may contribute to modulate metabolic processes associated with syndrome X, especially obesity and diabetes type 2. It is plausible, even though not exclusive, that these effects are linked to the microbiota-induced changes and it is feasible to conclude that their mechanisms fit into the prebiotic effect. However, the role of such changes in these health benefits remains to be definitively proven. As a result of the research activity that followed the publication of the prebiotic concept 15 years ago, it has become clear that products that cause a selective modification in the gut microbiota's composition and/or activity(ies) and thus strengthens normobiosis could either induce beneficial physiological effects in the colon and also in extra-intestinal compartments or contribute towards reducing the risk of dysbiosis and associated intestinal and systemic pathologies
PERFIL MICROBIOLÓGICO E QUÍMICO DE EXTRATOS PADRONIZADOS DE INGA MARGINATA
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
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
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
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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