Project description:The aim of this study was to identify TBBPA-degrading organisms in a complex microbial community by a metagenome-based functional metaproteomic approach, using protein-based stable isotope probing (protein-SIP). Firstly, the degradation kinetics were evaluated in order to simulate the decrease of residual mass of the labelled compound based on experimental data. In sequence, a metagenome was generated, and biomass was collected in different time-points for protein-SIP in incubations with 13C-TBBPA. This approach allowed for the identification organisms assimilating labelled carbon from the cometabolic degradation of a micropollutant.
Project description:3,3’,5.5’-Tetrabromobisphenol A (TBBPA) is a widely used brominated flame-retardant utilized in the production of electronic devices and plastic paints. The objective of this study is to use zebrafish as a model and determine the effects of TBBPA exposure on early embryogenesis. We initiated TBBPA exposures (0, 10, 20 and 40μM) at 0.75 h post fertilization (hpf) and monitored early developmental events such as cleavage, blastula and epiboly that encompass maternal-to-zygotic transition (MZT) and zygotic genome activation (ZGA). Our data revealed that TBBPA exposures induced onset of developmental delays by 3 hpf (blastula). By 5.5 hpf (epiboly), TBBPA-exposed (10-20 μM) embryos showed concentration-dependent developmental lag by up to 3 stages or 100% mortality at 40 μM. Interestingly, while continued 0.75- 48 hpf TBBPA exposures (10 μM) led to severely deformed embryos, replacing exposure solution with chemical-free media at 6 hpf mitigated this effect, with 100% normal embryos at 48 hpf. To examine the genetic basis of TBBPA-induced delays, we conducted mRNA-sequencing on embryos exposed to 0 or 40 μM TBBPA from 0.75 hpf to 2, 3.5 or 4.5 hpf. Read count data showed that while TBBPA exposures had no overall impacts on maternal or maternal-zygotic genes, collective read counts for zygotically activated genes were lower in TBBPA treatment at 4.5 hpf compared to time-matched controls, suggesting that TBBPA delays ZGA. Gene ontology assessments for both time- and stage-matched differentially expressed genes revealed TBBPA-induced inhibition of chromatin assembly- a process regulated by histone modifications. Since acetylation is the primary histone modification system operant during early ZGA, we hypothesized that TBBPA inhibits histone acetylation, resulting in lack of open chromatin within promoters of zygotic genes and delaying ZGA. Therefore, we co-exposed embryos to 20 μM TBBPA and 100 μM N-(4-Chloro-3-(trifluoromethyl)phenyl)-2-ethoxybenzamide (CTB) -a histone acetyltransferase activator that promotes histone acetylation- and showed that TBBPA-CTB co-exposures from 0.75- 3 hpf significantly reversed TBBPA-only developmental delays, suggesting that TBBPA-induced phenotypes are indeed driven by repression of histone acetylation. Collectively, our work demonstrates that TBBPA disrupts ZGA and early developmental morphology, potentially by inhibiting histone acetylation. Future studies will focus on mechanisms of TBBPA-induced chromatin modifications.
Project description:Vertebrate eye devlopment is partially regulated by thyroid hormones. TBBPA is a chemical that interacts with thyroid receptors. We investigated the effects of TBBPA on eye development of zebrafish. We expected TBBPA exposure to cause transcriptional changes of visual-system-related genes, which find their phenotypic anchoring in eye malformations and dysfunction, as observed in our previous studies. Additionally, the reversibility of effects after recovery in clean water for three days was investigated.
Project description:To identify liver transcripts differentially expressed due to treatment with tetrabromobisphenol A-bis(2,3-dibromopropyl ether) (TBBPA-DBPE), we collected RNA from male Harlan Sprague Dawley rats exposed to 0, 0.1, 0.94, 9.4, 94.3 or 943 mg/kg TBBPA.DBPE, 5 days after exposure for animals 7 weeks of age. These samples were interrogated with the Affymetrix Rat Genome 230 2.0 GeneChip array. A total of 0,0,0,0,0, and 0 gene transcripts were differentially expressed due to TBBPA.DBPE treatment after exposure to 0.1, 0.94, 9.4, 94.3 or 943 mg/kg TBBPA.DBPE (false discovery rate (FDR) < 0.05).
Project description:Study purpose: to explore the entire spectrum of proteomic and genomic changes (amongst others) involved in diseases and in healthy/control populations. The Study is designed to discover biomarkers, develop and validate diagnostic assays, instruments and therapeutics as well as other medical research. Specifically, researchers may analyze proteins, RNA, DNA copy number changes, including large and small (1,000-100,000 kb) scale rearrangements, transcription profiles, epigenetic modifications, sequence variation, and sequence in both diseased tissue and case-matched germline DNA from Subjects.
Project description:In this study, we differentiated mouse ESCs via 3D aggregates called embryoid bodies in presence of environmental and human relevant TBPPA concentrations for 28 days. We collected samples at different time points and analyzed TBBPA-dependent global gene expression changes by RNA-seq. Our analyses revealed a potential TBBPA multifaceted developmental toxicity with effects on the nervous and cardiac/skeletal muscle systems. Mechanistically, our findings suggest TBBPA endocrine disrupting activities in part via prolactin signaling.