Project description:Here, we established a successive Fe0-enhanced microbe system to remove azo dye (a typical organic pollutant) by Shewanella decolorationis S12 (S. decolorationis S12, an effective azo dye degradation bacterium) and examined the gene expression time course (10, 30, 60, and 120 min) in whole genome transcriptional level. Comparing with the treatment without ZVI, approximately 8% genes affiliated with 10 different gene expression profiles in S. decolorationis S12 were significantly changed in 120 min during the ZVI-enhanced microbial azo reduction. Intriguingly, MarR transcriptional factor might play a vital role in regulating ZVI-enhanced azo reduction in the aspect of energy production, iron homeostasis, and detoxification. Further investigation showed that induced [Ni-Fe] H2ase genes (hyaABCDEF) and azoreductase genes (mtrABC-omcA) contributed to ZVI-enhanced energy production, while reduced iron uptake (hmuVCB and feoAB), induced sulfate assimilation (cysPTWA) and cysteine biosynthesis (cysM) related genes were essential to iron homeostasis and detoxification. This study disentangles underlying mechanisms of ZVI-enhanced azo reduction in S. decolorationis S12 and lays a foundation for further optimization of integrated ZVI-microbial system for efficient organic pollution treatment.
Project description:Dyes used in fabric and leather industry are being released and accumulated into Canadian ecosystems. Recent studies have demonstrated that dyes made of azo compounds significantly increase toxicity in biota, which is explained by their toxic metabolites (e.g., aromatic amines). The metabolites of azo compounds interact with hydrophobic surfaces of cell membranes causing expansion of the membrane which impede normal cellular functions. It has been suggested that this process leads to cell death due to improper ion balance. Currently, it is estimated that between 10 and 15% of azo dyes are released in the environment as effluent. The aim of this study was to evaluate toxicity and gene networks altered by azo compounds in amphibians using ecotoxicogenomic approaches. Larvae of the frog Silurana tropicalis (Western clawed frog) were exposed to sediment contaminated to 887 ppm Disperse Yellow 7 (DY7). Larvae were exposed from Nieuwkoop-Faber developmental stage 12 to 46. Data suggest that the azo dye DY7 induced cellular stress and interfered with androgen biosynthesis in early tadpole development. At exposure completion, RNA was isolated from whole larvae and quality was ascertained using bioanalyzer analysis. A custom Agilent 4 X 44 K microarray for S. tropicalis was used to characterize gene regulatory networks underlying toxicity. This study presents the transcriptional regulatory pathways affected by DY7 in S. tropicalis early development. Embryos were exposed to the DY7 dye during development. There were 4 control groups exposed and 4 treatment groups exposed.
Project description:Dyes used in fabric and leather industry are being released and accumulated into Canadian ecosystems. Recent studies have demonstrated that dyes made of azo compounds significantly increase toxicity in biota, which is explained by their toxic metabolites (e.g., aromatic amines). The metabolites of azo compounds interact with hydrophobic surfaces of cell membranes causing expansion of the membrane which impede normal cellular functions. It has been suggested that this process leads to cell death due to improper ion balance. Currently, it is estimated that between 10 and 15% of azo dyes are released in the environment as effluent. The aim of this study was to evaluate toxicity and gene networks altered by azo compounds in amphibians using ecotoxicogenomic approaches. Larvae of the frog Silurana tropicalis (Western clawed frog) were exposed to sediment contaminated to 887 ppm Disperse Yellow 7 (DY7). Larvae were exposed from Nieuwkoop-Faber developmental stage 12 to 46. Data suggest that the azo dye DY7 induced cellular stress and interfered with androgen biosynthesis in early tadpole development. At exposure completion, RNA was isolated from whole larvae and quality was ascertained using bioanalyzer analysis. A custom Agilent 4 X 44 K microarray for S. tropicalis was used to characterize gene regulatory networks underlying toxicity. This study presents the transcriptional regulatory pathways affected by DY7 in S. tropicalis early development.