152 resultados para MICROBIAL DIVERSITY


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Diet diversity (defined as the number of different foods consumed) has been considered an indicator of a healthy diet, and favorably related to the risk of several digestive tract cancers. We analyzed the relation between diet diversity and the risk of laryngeal cancer using data from a case-control study carried out between 1992 and 2000 in Italy and Switzerland. The subjects of the study were 527 patients with histologically confirmed incident cancers of the larynx and 1297 patients admitted for acute, non-neoplastic diseases, unrelated to tobacco or alcohol consumption. Total diversity was computed as the number of different foods (overall and within four food groups, i.e., vegetables, fruit, meat, and cereals) consumed at least once per week. A significant inverse association was observed for vegetable diversity (OR=0.41, 95% CI: 0.28-0.59, for the highest versus the lowest quartile) and fruit diversity (OR=0.40, 95% CI: 0.27-0.59). Conversely, a direct association was found for meat diversity (OR=1.67, 95% CI: 1.11-2.50), while no meaningful association was found for total diet and cereal diversity. The results were consistent across strata of age, alcohol drinking and tobacco smoking. This study suggests that a diet not only rich but also varied in fruit and vegetables is related to a decreased risk of laryngeal cancer risk.

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The application of click chemistry to develop libraries of organometallic ruthenium-arene complexes with potential anticancer properties has been investigated. A series of ruthenium-imidazole-triazole complexes, with hydrophobic tails, were prepared from a common precursor via click chemistry. The tail could be attached to the ligand prior to coordination to the ruthenium complex were screened for cytotoxicity in tumourigenic and non-tumourigenic cell lines, and while the compounds were only moderately cytotoxic, good selectivity for tumourigenic cells were abserved.

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Superantigens (SAgs) are microbial proteins which have potent effects on the immune system. They are presented by major histocompatibility complex (MHC) class II molecules and interact with a large number of T cells expressing specific T cell receptor V beta domains. Encounter of a SAg leads initially to the stimulation and subsequently to the clonal deletion of reactive T cells. SAgs are expressed by a wide variety of microorganisms which use them to exploit the immune system to their own advantage. Bacterial SAgs are exotoxins which are linked to several diseases in humans and animals. A classical example is the toxic shock syndrome in which the massive release of cytokines by SAg-reactive cells is thought to play a major pathogenic role. The best characterized viral SAg is encoded by mouse mammary tumour virus (MMTV) and has proved to have a major influence on the viral life cycle by dramatically increasing the efficiency of viral infection. In this paper, we review the general properties of SAgs and discuss the different types of microorganisms which produce these molecules, with a particular emphasis on the role played by the SAg-induced immune response in the course of microbial infections.

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The aim of this survey is to assess the microbiological impact of irrigation water on lettuces produced on two urban agricultural sites and sold on markets; 6 and 7%, respectively, of lettuces coming from the sites of Pikine and Patte d'Oie were Salmonella spp. positive. Lettuces irrigated with shallow groundwater (''Ceanes'' water) were more contaminated (8% at both Pikine and Patte d'Oie sites) compared to those irrigated with wastewater (4% at Pikine) or well water (5% at Patte d'Oie). As for the lettuces in marketplaces, their contamination seems to depend on the type of treatment occurring before sale. Lettuces previously washed in the ``Ceanes'' were more contaminated than those rinsed with tap water at the marketplace. Salmonella spp. have been isolated from all marketplaces. However, the rates of contamination in markets surrounding Patte d'Oie are higher (9 and 11% at Grand Yoff and Dalifort) than those surrounding Pikine (4 and 2% at Zinc and Sham) or Rufisque, the control (2%). Our results confirm that the reuse of wastewater in irrigation is an alternative to animal manure. Its risk of microbial contamination can be significantly reduced by washing the vegetables with tap water before they are sold. Copyright (C) 2010 John Wiley & Sons, Ltd.

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Protected areas are valuable in conserving tropical biodiversity, but an insufficient understanding of species diversity and distributions makes it difficult to evaluate their effectiveness. This is especially true on Borneo, a species rich island shared by three countries, and is particularly concerning for bats, a poorly known component of mammal diversity that may be highly susceptible to landscape changes. We reviewed the diversity, distributions and conservation status of 54 bat species to determine the representation of these taxa in Borneo's protected areas, and whether these reserves complement each other in terms of bat diversity. Lower and upper bound estimates of bat species composition were characterised in 23 protected areas and the proposed boundaries of the Heart of Borneo conservation area. We used lower and upper bound estimates of species composition. By using actual inventories, species representation was highly irregular, and even if some reserves were included in the Heart of Borneo, the protected area network would still exhibit low complementarity. By inferring species presence from distributions, composition between most reserves was similar, and complementarity was much higher. Predicting species richness using abundance information suggested that bat species representation in reserves may lie between these two extremes. We recommend that researchers better sample biodiversity over the island and address the conservation threats faced in Borneo both within and outside protected areas. While the Heart of Borneo Initiative is commendable, it should not divert attention from other conservation areas.

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Genetic diversity is the amount of variation observed between DNA sequences from distinct individuals of a given species. This pivotal concept of population genetics has implications for species health, domestication, management and conservation. Levels of genetic diversity seem to vary greatly in natural populations and species, but the determinants of this variation, and particularly the relative influences of species biology and ecology versus population history, are still largely mysterious. Here we show that the diversity of a species is predictable, and is determined in the first place by its ecological strategy. We investigated the genome-wide diversity of 76 non-model animal species by sequencing the transcriptome of two to ten individuals in each species. The distribution of genetic diversity between species revealed no detectable influence of geographic range or invasive status but was accurately predicted by key species traits related to parental investment: long-lived or low-fecundity species with brooding ability were genetically less diverse than short-lived or highly fecund ones. Our analysis demonstrates the influence of long-term life-history strategies on species response to short-term environmental perturbations, a result with immediate implications for conservation policies.

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Glomalean fungi induce and colonize symbiotic tissue called arbuscular mycorrhiza on the roots of most land plants. Other fungi also colonize plants but cause disease not symbiosis. Whole-transcriptome analysis using a custom-designed Affymetrix Gene-Chip and confirmation with real-time RT-PCR revealed 224 genes affected during arbuscular mycorrhizal symbiosis. We compared these transcription profiles with those from rice roots that were colonized by pathogens (Magnaporthe grisea and Fusarium moniliforme). Over 40% of genes showed differential regulation caused by both the symbiotic and at least one of the pathogenic interactions. A set of genes was similarly expressed in all three associations, revealing a conserved response to fungal colonization. The responses that were shared between pathogen and symbiont infection may play a role in compatibility. Likewise, the responses that are different may cause disease. Some of the genes that respond to mycorrhizal colonization may be involved in the uptake of phosphate. Indeed, phosphate addition mimicked the effect of mycorrhiza on 8% of the tested genes. We found that 34% of the mycorrhiza-associated rice genes were also associated with mycorrhiza in dicots, revealing a conserved pattern of response between the two angiosperm classes.

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(Résumé de l'ouvrage) This volume embodies an uptodate and sensitive set of studies exploring the ongoing negotiation of European Muslim identities in Europe. The Editor argues there has been hitherto a three-fold response on the part of Muslims in Europe (some of whom are now 3rd generation Europeans) - integrationism, isolationism, and escapism. Today the latter two responses are giving way, it is argued, to an active shaping of Muslim European identities. The central issue remains: what degree of freedom and what potential for cultural and religious diversity can minorities have in an outwardly secular and plural European society?

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Epstein-Barr virus (EBV) is associated with several types of cancers including Hodgkin's lymphoma (HL) and nasopharyngeal carcinoma (NPC). EBV-encoded latent membrane protein 1 (LMP1), a multifunctional oncoprotein, is a powerful activator of the transcription factor NF-κB, a property that is essential for EBV-transformed lymphoblastoid cell survival. Previous studies reported LMP1 sequence variations and induction of higher NF-κB activation levels compared to the prototype B95-8 LMP1 by some variants. Here we used biopsies of EBV-associated cancers and blood of individuals included in the Swiss HIV Cohort Study (SHCS) to analyze LMP1 genetic diversity and impact of sequence variations on LMP1-mediated NF-κB activation potential. We found that a number of variants mediate higher NF-κB activation levels when compared to B95-8 LMP1 and mapped three single polymorphisms responsible for this phenotype: F106Y, I124V and F144I. F106Y was present in all LMP1 isolated in this study and its effect was variant dependent, suggesting that it was modulated by other polymorphisms. The two polymorphisms I124V and F144I were present in distinct phylogenetic groups and were linked with other specific polymorphisms nearby, I152L and D150A/L151I, respectively. The two sets of polymorphisms, I124V/I152L and F144I/D150A/L151I, which were markers of increased NF-κB activation in vitro, were not associated with EBV-associated HL in the SHCS. Taken together these results highlighted the importance of single polymorphisms for the modulation of LMP1 signaling activity and demonstrated that several groups of LMP1 variants, through distinct mutational paths, mediated enhanced NF-κB activation levels compared to B95-8 LMP1.