101 research outputs found

    Influence of phenological barriers and habitat differentiation on the population genetic structure of the balearic endemic Rhamnus ludovici-salvatoris Chodat and R. alaternus L

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    [EN] Rhamnus ludovici-salvatoris, endemic to the Gymnesian Islands, coexists with the related and widespread R. alaternus in Mallorca and Menorca. In both species, the population genetic structure using RAPD, and flowering during a 3-year period to check for possible phenological barriers, were analyzed. Rhamnus ludovici-salvatoris showed lower genetic diversity and stronger population structure than R. alaternus, the Cabrera population being less diverse and the most differentiated. Rhamnus ludovici-salvatoris flowered one month later, although flowering of both species coincided sporadically. These congeners seem to have diverged through isolation by time and differentiation in habitat. The population genetic structure of R. ludovici-salvatoris could mainly be due to the existence of small populations on the one hand, and a gene flow caused by rare hybridization events on the other, which may also explain the presence of morphologically intermediate individuals in Menorca. 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    The effectiveness of e-Learning on biosecurity practice to slow the spread of invasive alien species

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    Online e-Learning is increasingly being used to provide environmental training. Prevention measures including biosecurity are essential to reducing the introduction and spread of invasive alien species (IAS) and are central to international and national IAS policy. This paper is the first to evaluate the effectiveness of e-Learning as a tool to increase awareness, risk perception and biosecurity behaviour in relation to IAS among individuals conducting work activities or research (fieldwork) in the field. We surveyed participants (a mixture of students and professionals) before, and 6 months after undertaking an e-Learning course on IAS and biosecurity practices. Awareness of IAS and self-reported biosecurity behaviour increased after e-Learning among students and professionals. Students had a lower awareness of IAS than professionals before training (20% of students vs 60% of professionals), but after training students showed a greater increase in awareness which led to similar levels of awareness post-training (81%). Prior to training, risk perception was also lower amongst students than professionals (33% of students and 59% of professionals were aware of the risk that their activities posed to the accidental spread of IAS). There was no change in risk perception amongst professionals after training, however training led to a doubling of risk perception in students. E-Learning also led to an increase in reported biosecurity behaviour and cleaning practices and there were higher levels of biosecurity cleaning amongst professionals. The higher awareness and better biosecurity amongst professionals is likely to reflect their familiarity with the issues of IAS and day-to-day activities in the field. Our results suggest that e-Learning is an effective tool to raise awareness and encourage behaviour change among field workers and researchers in an attempt to reduce the risk of accidental introduction and spread of IAS

    Functional Characterization of a Lipoprotein-Encoding Operon in Campylobacter jejuni

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    Background: Bacterial lipoproteins have important functions in bacterial pathogenesis and physiology. In Campylobacter jejuni, a major foodborne pathogen causing gastroenteritis in humans, the majority of lipoproteins have not been functionally characterized. Previously, we showed by DNA microarray that CmeR, a transcriptional regulator repressing the expression of the multidrug efflux pump CmeABC, modulates the expression of a three-gene operon (cj0089, cj0090, and cj0091) encoding a cluster of lipoproteins in C. jejuni. Methodology/Principal Findings: In this work, we characterized the function and regulation of the cj0089-cj0090-cj0091 operon. In contrast to the repression of cmeABC, CmeR activates the expression of the lipoprotein genes and the regulation is confirmed by immunoblotting using anti-Cj0089 and anti-Cj0091 antibodies. Gel mobility shift assay showed that CmeR directly binds to the promoter of the lipoprotein operon, but the binding is much weaker compared with the promoter of cmeABC. Analysis of different cellular fractions indicated that Cj0089 was associated with the inner membrane, while Cj0091 was located on the outer membrane. Inactivation of cj0091, but not cj0089, significantly reduced the adherence of C. jejuni to INT 407 cells in vitro, indicating that Cj0091 has a function in adherence. When inoculated into chickens, the Cj0091 mutant also showed a defect in early colonization of the intestinal tract, suggesting that Cj0091 contributes to Campylobacter colonization in vivo. It was also shown that Cj0091 was produced and immunogenic in chickens that wer

    Comparative genomics of Pseudomonas fluorescens subclade III strains from human lungs

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    Abstract Background While the taxonomy and genomics of environmental strains from the P. fluorescens species-complex has been reported, little is known about P. fluorescens strains from clinical samples. In this report, we provide the first genomic analysis of P. fluorescens strains in which human vs. environmental isolates are compared. Results Seven P. fluorescens strains were isolated from respiratory samples from cystic fibrosis (CF) patients. The clinical strains could grow at a higher temperature (>34 °C) than has been reported for environmental strains. Draft genomes were generated for all of the clinical strains, and multi-locus sequence analysis placed them within subclade III of the P. fluorescens species-complex. All strains encoded type- II, −III, −IV, and -VI secretion systems, as well as the widespread colonization island (WCI). This is the first description of a WCI in P. fluorescens strains. All strains also encoded a complete I2/PfiT locus and showed evidence of horizontal gene transfer. The clinical strains were found to differ from the environmental strains in the number of genes involved in metal resistance, which may be a possible adaptation to chronic antibiotic exposure in the CF lung. Conclusions This is the largest comparative genomics analysis of P. fluorescens subclade III strains to date and includes the first clinical isolates. At a global level, the clinical P. fluorescens subclade III strains were largely indistinguishable from environmental P. fluorescens subclade III strains, supporting the idea that identifying strains as ‘environmental’ vs ‘clinical’ is not a phenotypic trait. Rather, strains within P. fluorescens subclade III will colonize and persist in any niche that provides the requirements necessary for growth.http://deepblue.lib.umich.edu/bitstream/2027.42/116129/1/12864_2015_Article_2261.pd

    Evolutionary dynamics of emblematic Araucaria species (Araucariaceae) in New Caledonia:Nuclear and chloroplast markers suggest recent diversification, introgression, and a tight link between genetics and geography within species

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    BACKGROUND: New Caledonia harbours a highly diverse and endemic flora, and 13 (out of the 19 worldwide) species of Araucaria are endemic to this territory. Their phylogenetic relationships remain largely unresolved. Using nuclear microsatellites and chloroplast DNA sequencing, we focused on five closely related Araucaria species to investigate among-species relationships and the distribution of within-species genetic diversity across New Caledonia. RESULTS: The species could be clearly distinguished here, except A. montana and A. laubenfelsii that were not differentiated and, at most, form a genetic cline. Given their apparent morphological and ecological similarity, we suggested that these two species may be considered as a single evolutionary unit. We observed cases of nuclear admixture and incongruence between nuclear and chloroplast data, probably explained by introgression and shared ancestral polymorphism. Ancient hybridization was evidenced between A. biramulata and A. laubenfelsii in Mt Do, and is strongly suspected between A. biramulata and A. rulei in Mt Tonta. In both cases, extensive asymmetrical backcrossing eliminated the influence of one parent in the nuclear DNA composition. Shared ancestral polymorphism was also observed for cpDNA, suggesting that species diverged recently, have large effective sizes and/or that cpDNA experienced slow rates of molecular evolution. Within-species genetic structure was pronounced, probably because of low gene flow and significant inbreeding, and appeared clearly influenced by geography. This may be due to survival in distinct refugia during Quaternary climatic oscillations. CONCLUSIONS: The study species probably diverged recently and/or are characterized by a slow rate of cpDNA sequence evolution, and introgression is strongly suspected. Within-species genetic structure is tightly linked with geography. We underline the conservation implications of our results, and highlight several perspectives. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12862-014-0171-6) contains supplementary material, which is available to authorized users

    The conundrum of iron in multiple sclerosis – time for an individualised approach

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