Project description:Genome-wide DNA methylation profiling of peripheral blood mononuclear cells from 30 male offspring from the Yucheng (perinatal polychlorinated biphenyls and polychlorinated dibenzofurans exposure) cohort and 30 male offspring from the Yucheng' neighborhood referents with similar backgrounds. The Infinium HumanMethylation450 BeadChip was used to obtain DNA methylation profiles across appromixmately 480,000 CpGs.
Project description:Hornyhead turbot (Pleuronichthys verticalis), a sentinel flatfish species, were intraperitoneally injected with environmentally relevant mixtures of polybrominated diphenyl ethers (PBDEs) or polychlorinated biphenyls (PCBs). After 96 h, fish were sacrificed and liver tissue was collected for gene expression analysis using a custom-designed microarray.
Project description:Volatilization of lower-chlorinated polychlorinated biphenyls (LC-PCBs) from sediment poses health threats to nearby communities and ecosystems. Biodegradation combined with black carbon (BC) materials is an emerging approach to remove PCBs from sediment, but development of aerobic biofilms on BC for long-term, sustained LC-PCBs remediation is poorly understood. This work aimed to characterize cell enrichment and activity of biphenyl- and benzoate-grown Paraburkholderia xenovorans strain LB400 on various BCs. Biphenyl dioxygenase gene (bphA) abundance on four BC types demonstrated corn kernel biochar hosted at least four orders of magnitude more attached cells per gram than other feedstocks, and microscopic imaging revealed the attached live cell fraction was >1.5X more on corn kernel biochar than GAC. BC characteristics (i.e., sorption potential, surface area, pH) drove cell attachment differences. Reverse transcription qPCR indicated BC feedstocks significantly influenced bphA expression in attached cells. The bphA transcript-per-gene ratio of attached cells was >10-fold more than suspended cells, confirmed by transcriptomics. RNA-seq also demonstrated significant upregulation of biphenyl and benzoate degradation pathways on attached cells, revealing biofilm formation potential and cell-cell communication pathway connections. These novel findings demonstrate aerobic PCB-degrading cell abundance and activity could be tuned by adjusting BC feedstocks/ attributes to improve LC-PCBs biodegradation.
Project description:Hydroxylated polychlorinated biphenyls are the metabolites produced from polychlorinated biphenyls (PCBs) by drug-metabolizing enzyme cytochrome P450 1A1. These compounds are bound to transthyretin, a major plasma thyroid hormone-binding protein in amphibian tadpoles. The compounds-transthyretin complexes are transferred into the brain across the blood brain barrier in mammals. Thus these compounds are suspected to disrupt neural development in brain. We studied about the effects of hydroxylated PCBs on the thyroid system in brain using metamorphosing tadpoles of African clawed toad, Xenopus laevis. The metamorphosis assay revealed that these compounds had inhibitory effects on the thyroid hormone-induced metamorphosis. This in vivo assay was a powerful tool to detect thyroid-disrupting activities, because we were not able to detect the inhibitory effects of these compounds using thyroid hormone-responsive reporter gene assay in a cultured Xenopus cell line. A genome-wide gene expression analysis in brain following short-term exposure to these compounds demonstrated that the delay of metamorphosis and the morphological thyroid-disrupting changes could be caused partially by disruption of the thyroid hormone-induced gene expression by hydroxylated PCBs. Furthermore, we associated functional ontology terms with the transcripts whose expression were altered by thyroid hormone alone, or thyroid hormone and hydroxylated PCBs. We suggested that these approachs using a technique of bioinformatics revealed molecular mechanism of thyroid-disrupting activities in vivo. Thyroid hormones induce amphibian metamorphosis and alter a lot of thyroid hormone-responsive gene expression. We studied about the effects of hydroxylated PCBs on TH-induced gene expression. Premetamorphic tadpoles were treated with 500 nM hydroxylated PCBs in the presence of 1 nM thyroid hormone for 4 days. After exposure period total RNA was extracted from brain. Study included at least three replicate of each treatment.
