2,152 research outputs found

    The MINOS Detectors

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    Epigenetic modifications affect the rate of spontaneous mutations in a pathogenic fungus

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    Mutations are the source of genetic variation and the substrate for evolution. Genome-widemutation rates appear to be affected by selection and are probably adaptive. Mutation ratesare also known to vary along genomes, possibly in response to epigenetic modifications, butcausality is only assumed. In this study we determine the direct impact of epigenetic mod-ifications and temperature stress on mitotic mutation rates in a fungal pathogen using amutation accumulation approach. Deletion mutants lacking epigenetic modifications confirmthat histone mark H3K27me3 increases whereas H3K9me3 decreases the mutation rate.Furthermore, cytosine methylation in transposable elements (TE) increases the mutation rate15-fold resulting in significantly less TE mobilization. Also accessory chromosomes havesignificantly higher mutation rates. Finally, wefind that temperature stress substantiallyelevates the mutation rate. Taken together, wefind that epigenetic modifications andenvironmental conditions modify the rate and the location of spontaneous mutations in thegenome and alter its evolutionary trajectory

    Microbial Community Response to Various Degrees of Pasture Soil Disturbance

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    Commercial dairy farming from planted pasture is commonly practised in the southern Cape region of South Africa. These pastures are established by various methods ranging in degree of disturbance from no-tillage to conventional tillage. Different establishment methods may alter the below-ground ecosystem, and depending on the degree of disturbance, lead to changes in microbial biodiversity and soil health. Disturbance of pasture soil may play an important role in regulating soil microbial community structure. The aim of this study was to investigate changes in soil microbial community-level physiological profiles of kikuyu (Pennisetum clandestinum) pastures reinforced with annual ryegrass (Lolium multiflorum) by various degrees of soil disturbance
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