14 research outputs found

    Cytosine methylation profiling of cancer cell lines

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    DNA-methylation changes in human cancer are complex and vary between the different types of cancer. Capturing this epigenetic variability in an atlas of DNA-methylation changes will be beneficial for basic research as well as translational medicine. Hypothesis-free approaches that interrogate methylation patterns genome-wide have already generated promising results. However, these methods are still limited by their quantitative accuracy and the number of CpG sites that can be assessed individually. Here, we use a unique approach to measure quantitative methylation patterns in a set of >400 candidate genes. In this high-resolution study, we employed a cell-line model consisting of 59 cancer cell lines provided by the National Cancer Institute and six healthy control tissues for discovery of methylation differences in cancer-related genes. To assess the effect of cell culturing, we validated the results from colon cancer cell lines by using clinical colon cancer specimens. Our results show that a large proportion of genes (78 of 400 genes) are epigenetically altered in cancer. Although most genes show methylation changes in only one tumor type (35 genes), we also found a set of genes that changed in many different forms of cancer (seven genes). This dataset can easily be expanded to develop a more comprehensive and ultimately complete map of quantitative methylation changes. Our methylation data also provide an ideal starting point for further translational research where the results can be combined with existing large-scale datasets to develop an approach that integrates epigenetic, transcriptional, and mutational findings

    Mycorrhizal effectiveness and manganese toxicity in soybean as affected by soil type and endophyte Eficiência micorrízica e toxidez de manganês em soja em função do tipo de solo e da espécie do endófito

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    Mycorrhizal plants may present Mn toxicity alleviation and this depends on the plant-endophyte-environment interaction. The effectiveness of three arbuscular mycorrhizal fungi (AMF) (Glomus macrocarpum, G. etunicatum, G. intraradices) and a control without AMF in two soils: Typic Rhodudalf with high Mn availability and a Typic Quartzipsamment, with low Mn availability, was evaluated in a time-course experiment at 3, 6, 9 and 12 weeks after soybean (Glycine max L.) seedling emergence. The objective was to select the most effective AMF species to enhance plant growth and to assess its effects upon Mn uptake by plants and Mn availability in the soil. For the sandy soil, AMF inoculation resulted in increased plant biomass, especially with G. intraradices and G. etunicatum. Lower Mn concentrations were observed in shoot and root of mycorrhizal plants. For the clayey soil, there was also an increase in plant biomass, but only for plants inoculated with G. intraradices and G. etunicatum. Mycorrhizal plants presented higher Mn concentrations in shoot and root and there was an increase of available Mn in the soil, in relation to the control, especially in the treatment with G. macrocarpum. When inoculated with G. macrocarpum, plants presented Mn toxicity symptoms and reduced biomass in comparison to control plants. The effects of mycorrhizal inoculation, either positive or negative, were most intense at 9 and 12 weeks.<br>Plantas micorrizadas podem apresentar atenuação da toxidez causada pelo excesso de Mn, mas isso depende da interação planta-endófito-ambiente. Avaliou-se a eficiência de três espécies de fungos micorrízicos arbusculares (FMA) (Glomus macrocarpum, G. etunicatum, G. intraradices, e um controle sem FMA, em quatro épocas de coleta (3, 6, 9 e 12 semanas após a emergência das plântulas de soja (Glycine max L.)) num Nitossolo Vermelho eutroférrico típico, muito argiloso, com alta disponibilidade de Mn e num Neossolo Quartzarênico típico, com baixa disponibilidade de Mn. O objetivo foi avaliar a eficiência micorrízica desses FMA nesses substratos, em diversas épocas, bem como os efeitos sobre a disponibilidade de Mn no substrato e sua absorção pelas plantas. No substrato arenoso, a micorrização aumentou a biomassa das plantas, com destaque para G. intraradices e G. etunicatum. Nesse caso, houve menor concentração de Mn na parte aérea e raízes das plantas. No substrato argiloso, a micorrização com G. intraradices e G. etunicatum aumentou a biomassa das plantas, mas também aumentou a disponibilidade de Mn no substrato e a concentração na parte aérea e raízes em relação ao controle, com mais intensidade nas plantas com G. macrocarpum. Nesse caso, houve sintomas de toxidez de Mn e diminuição da biomassa das plantas. Os efeitos da micorrização, positivos ou negativos, foram mais expressivos com 9 e 12 semanas

    Fungos micorrízicos arbusculares em seringueira em latossolo amarelo distrófico da amazônia ocidental Arbuscular mycorrhizae fungi, growth and nutrient content in rubber plants in a xanthic ferrasol of western amazon

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    A colonização radicular com fungos micorrízicos arbusculares (FMA) pode aumentar a eficiência no crescimento e absorção de nutrientes pelas plantas. Com o objetivo de verificar esse efeito, foram avaliados o grau de colonização em seringais adultos cultivados em Latossolo Amarelo distrófico e a eficiência de seis FMAs na colonização, crescimento e estado nutricional de mudas de seringueira com três e seis meses de transplantio. Os resultados indicaram baixo grau de colonização micorrízica e número de esporos em seringal adulto. Seis meses depois do transplantio das mudas de seringueira foram suficientes para ocorrer colonização de FMAs detectável. Não houve aumento no incremento em altura, diâmetro e emissão de folhas, independentemente do inóculo utilizado. Os teores foliares de nutrientes (N, P, K, Ca, Mg, Cu, Fe, Mn e Zn) também não foram influenciados pelo número de esporos e grau de colonização, havendo diferenças apenas em função da idade das plantas.<br>The infection roots with arbuscular mycorrhizal fungi (AMF) can increase the efficiency in growth and nutrients uptake of plants. With the objective to verify this effect, the degree of colonization in rubber tree plantation cultivated in a Xanthic Ferralsol (dystrophic Yellow Latosol) and the efficiency of six AMF in colonization, growth and nutritional status of rubber tree seedlings were evaluated, with three and six months of transplanting. The results showed a low level of mycorrhizal infection and number of spores in adult rubber tree. Six months of transplanting of rubber tree seedlings were sufficient detectable AMFs infection. There was no increase in height, diameter and number of leaves. The foliar nutrients concentration (N, P, K, Ca, Mg, Cu, Fe, Mn and Zn) were also not influenced by the number of spores and infection degree, with only differences by age of the plants (three and six months of transplanting)
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