Project description:Based on the magnesium (Mg) tolerance test, the "gold standard" test of Mg status, more than 50% US participants had Mg deficiency. Observations suggest that the associations between high Mg intake and disease risks may completely differ by the underlying Mg status. Due to major limitations, the Mg tolerance test is not used in conventional clinical practice and rarely used in research. Instead, serum Mg is used for clinical diagnosis. However, serum Mg performs very poorly at identifying those with Mg deficiency. There is a great need to develop implementable, sensitive, and specific biomarkers which can be easily used for identifying people with Mg deficiency.
It is known that DNA methylation changes are inducible by environmental exposures, including nutrients, and reversible when the exposure disappears. We propose to identify 5-hmC/5-mC biomarkers for Mg deficiency by a 4- phase EWAS study in the "Personalized Prevention of Colorectal Cancer Trial [PPCCT, R01CA149633; PI, Dai & Yu]" with a total of 240 participants. Mg tolerance test will be used as the gold standard. Finally, using newly identified biomarkers, we will evaluate if 12-week Mg treatment reduces TRPM7 expression, essential in Mg homeostasis and colorectal carcinogenesis, in rectal tissues only among those with Mg deficiency.
Project description:Many normal tissues undergo age-related DNA methylation drift providing a quantitative measure of tissue age. However this drift has not been demonstrated in neoplastic tissues. Here we identify and validate 781 CpG-islands (CGIs) that undergo significant methylomic drift in normal colorectal tissues continue to drift in neoplasia and remain significantly correlated with one another across tissue samples. However compared with normal colon this drift advances (~3-4 fold) faster in neoplasia consistent with increased cell proliferation during neoplastic progression. Furthermore we show that the observed drift patterns are broadly consistent with modeled adenoma-carcinoma sojourn time distributions from colorectal cancer (CRC) incidence data. These results support the hypothesis that beginning with the founder premalignant cell cancer precursors frequently sojourn for decades before turning into cancer which implies that the founder cell typically arises early in life. We estimate that at least 77-89% of the observed drift variance in distal and rectal tumors is explained by stochastic variability associated with neoplastic progression while only 55% of the variance is explained for proximal tumors. However >50% of identified gene-CGI pairs in the proximal colon that undergo drift are significantly and mainly negatively correlated with cancer gene expression suggesting that methylomic drift participates in the clonal evolution of CRCs. Significance: Methylomic drift advances in colorectal neoplasia consistent with extended sojourn time distributions explaining a significant fraction of epigenetic heterogeneity in CRCs. Importantly the estimated long-duration premalignant sojourn times suggest that early dietary and lifestyle interventions may be more effective than later changes in reducing CRC incidence.
Project description:B. pertussis GMT-1 was grown in media containing magnesium sulfate to put the culture in the Bvg- phase. The cells were then washed and grown in media lacking magnesium sulfate and samples were harvested at time=0 and several time points beyond.
Project description:Gene expression profiling in soybean under aluminum stress: mechanisms of magnesium amelioration of aluminum toxicity at gene expression level. Micro-molar concentrations of magnesium in culture solution has been shown to ameliorate Al toxicity in soybean and other leguminous species. Different theories have been proposed to explain the chemical mechanisms of how the two ions interact to neutralize the toxic effect of aluminum in the plant root system. To understand the molecular mechanisms of the phenomenon at the gene expression level in soybean, we undertook a comparative transcriptome analysis in Al-tolerant and Al-sensitive genotypes treated with aluminum alone or aluminum plus magnesium using DNA microarrays. The results revealed magnesium enhances Al-tolerance level in the Al-tolerant genotype by down-regulating genes commonly induced in response to Al toxicity. We hypothesized that the magnesium-mediated alleviation of Al toxicity in the Al-tolerant genotype emanates from reduction in energy expenditure of gene expression induced in response to Al stress. Conversely, magnesium appears to ameliorate Al toxicity in the sensitive genotype by dual mechanisms of increasing the expression level of several genes involved in Al-tolerance and decreasing the expression level of most genes. Keywords: Soybean, aluminum toxicity, magnesium, transcriptome Two genotypes: PI 416937 (p) and Young (y); two treatments: Aluminum (Al) or Al+magnesium (Mg); two time points: 12 and 72 hrs; 3 replicates.
Project description:Martian regolith (unconsolidated surface material) is a potential medium for plant growth in bioregenerative life support systems during manned missions on Mars. However, hydrated magnesium sulfate mineral levels in the regolith of Mars can reach as high as 10 wt%, and would be expected to be highly inhibitory to plant growth. A global approach was used to identify novel genes with potential to enhance tolerance to high MgSO4 stress. The early Arabidopsis root transcriptome response to elevated concentrations of magnesium sulfate was characterized in col-0, and also between col-0 and the mutant line cax1-1 – a mutant relatively tolerant of high levels of MgSO4•7H2O in soil solution. After 3 weeks of growth under hydroponic conditions, Arabidopsis thaliana col-0 roots were exposed to a basic nutrient solution (0.25 g/L MES, 1/16x MS, pH 5.7) with an additional 2.08 mM magnesium sulfate (total Ca:Mg ratio = 1:15) for 45 min., 90 min., or 180 min., while a col-0 control set was exposed to the basic nutrient solution without additional magnesium sulfate for 45 minutes. Arabidopsis thaliana cax1-1 roots were exposed to the basic nutrient solution with additional magnesium sulfate for 180 min. only. Four replicate containers were harvested for the control and each of the treatment sets, resulting in a total of 20 samples. Gene expression of the col-0 sets exposed to magnesium sulfate treatment for 45 min., 90 min., or 180 min. was compared to gene expression of the col-0 control set. Gene expression of the cax1-1 set exposed to magnesium sulfate treatment for 180 min. was compared to gene expression of the col-0 set exposed to magnesium sulfate treatment for 180 minutes.
Project description:Gene expression profiling in soybean under aluminum stress: mechanisms of magnesium amelioration of aluminum toxicity at gene expression level. Micro-molar concentrations of magnesium in culture solution has been shown to ameliorate Al toxicity in soybean and other leguminous species. Different theories have been proposed to explain the chemical mechanisms of how the two ions interact to neutralize the toxic effect of aluminum in the plant root system. To understand the molecular mechanisms of the phenomenon at the gene expression level in soybean, we undertook a comparative transcriptome analysis in Al-tolerant and Al-sensitive genotypes treated with aluminum alone or aluminum plus magnesium using DNA microarrays. The results revealed magnesium enhances Al-tolerance level in the Al-tolerant genotype by down-regulating genes commonly induced in response to Al toxicity. We hypothesized that the magnesium-mediated alleviation of Al toxicity in the Al-tolerant genotype emanates from reduction in energy expenditure of gene expression induced in response to Al stress. Conversely, magnesium appears to ameliorate Al toxicity in the sensitive genotype by dual mechanisms of increasing the expression level of several genes involved in Al-tolerance and decreasing the expression level of most genes. Keywords: Soybean, aluminum toxicity, magnesium, transcriptome
Project description:Dynamic changes to the epigenome mediate key neurobiological and cognitive processes in the central nervous system, and also play a role in transcriptional regulation during brain development. Although the importance of DNA methylation in brain development is highlighted by the neurodevelopmental deficits associated with mutations in genes including methyl-CpG binding protein 2 (MECP2), our knowledge about the specific methylomic trajectories associated with human neurodevelopment is extremely limited. Here we report an analysis of genome-wide patterns of DNA methylation in 179 human fetal cortex samples. Bisulphite converted DNA from 179 human brain samples was hybridized to the Illumina 450K Human Methylation Beadchip.
Project description:A mapping population of Brassica rapa (BraIRRI, IMB211xR500) was grown under four external calcium and magnesium concentrations in controlled conditions. RNA was extracted and hybridised to the Affymetrix Brassica Exon 1.0 ST array. The aim of the experiment was to identify cis- and trans- expression quantitative trait loci.