ABSTRACT: Exposure to Deepwater Horizon Oil and Corexit 9500 at Low Concentrations Induces Transcriptional Changes and Alters Immune Transcriptional Pathways in Sheepshead Minnows
Project description:To investigate molecular effects in fish following exposure to environmentally relevant concentrations of dispersants and DWH oil, we exposed adult sheepshead minnows (Cyprinodon variegatus) to Corexit 9500™ and two concentrations of high-energy water-accommodated fraction (HEWAF) or chemically enhanced water-accommodated fraction (CEWAF) for 7 and 14 days. Resulting changes in hepatic gene expression were measured using Agilent 8x15K microarrays. We observed significant changes to gene expression in all treatments (relative to controls), with Corexit and CEWAF having a greater effect on expression patterns in the liver than HEWAF treatments. Sub-network enrichment analysis of biological pathways revealed that the greatest number of altered pathways in high dose HEWAF and CEWAF treatments occurred following a 7-day exposure. Pathways related to immunity comprised the majority of pathways affected in each treatment, followed by pathways related to blood and circulation processes.
Project description:To reveal the potential effects of oil and oil dispersants on the respiratory system at the molecular level, we evaluated the transcriptomic profile of human airway epithelial cells grown under treatment of crude oil, the dispersants Corexit 9500 and Corexit 9527 and oil-dispersant mixtures. We identified a very strong effect of Corexit 9500 treatment, with 84 genes (response genes) differentially expressed in treatment vs. control samples. We discovered an interactive effect of oil + dispersant mixtures; while no response gene was found for Corexit 9527 treatment alone, cells treated with Corexit 9527 + oil mixture showed an increased number of response genes (46 response genes), suggesting a synergic effect of 9527 with oil on the transcriptomic perturbation of airway epithelial cells. Through GO (gene ontology) functional term and pathway-based analysis, we identified upregulation of genes involved in angiogenesis and immune responses and downregulation of genes involved in cell junctions and steroid synthesis as the prevailing transcriptomic signatures in the cells treated with Corexit 9500, oil or Corexit 9500 + oil mixture. Interestingly, these key molecular features coincide with those observed in common lung diseases, such as asthma, cystic fibrosis and chronic obstructive pulmonary disease. Our study provides mechanistic insights into the detrimental effects of oil and oil dispersants to the respiratory system and suggested significant health impacts of the recent BP oil spill to those people involved in the cleaning operation.
Project description:The application of chemical dispersants during marine oil spills can affect the community composition and activity of native marine microorganisms. Several studies have indicated that certain marine hydrocarbon-degrading bacteria, such as Marinobacter spp., can be inhibited by chemical dispersants, resulting in lower abundances and/or reduced hydrocarbon-biodegradation rates. In this respect, a major knowledge gap exists in understanding the mechanisms underlying these observed physiological effects. Here, we performed comparative proteomics of the Deepwater Horizon isolate Marinobacter sp. TT1 grown under different conditions that varied regarding the supplied carbon sources (pyruvate vs. n-hexadecane) and whether or not dispersant (Corexit EC9500A) was added, or that contained crude oil in the form of a water-accommodated fraction (WAF) or chemically-enhanced WAF (CEWAF). We characterized the proteins associated with alkane metabolism and alginate biosynthesis in strain TT1, report on its potential for aromatic hydrocarbon biodegradation and present a proposed metabolism of Corexit components as carbon substrates for the strain. Our findings implicate Corexit in affecting hydrocarbon metabolism, chemotactic motility, biofilm formation, and inducing solvent tolerance mechanisms like efflux pumps in strain TT1. This study provides novel insights into dispersant impacts on microbial hydrocarbon degraders that should be taken into consideration for future oil spill response actions.
Project description:Genome-wide expression assay of S. alterniflora individuals from populations (4 from Louisiana, 2 from Mississippi) either exposed or unexposed to the Deepwater Horizon oil spill
Project description:Adult male marine fish were exposed to 100ng/L of ethinyl estradiol (EE2) for 7 days in 1.8L vessels, dimethyl sulfoxide (DMSO) was used as carrier never reaching concentrations > 0.001% v/v. The same volume of DMSO was added to the solvent control vessels. Culture conditions, monitored daily, were as follows: temperature 18.8 ± 0.2°C, pH 7.94±0.03, dissolved oxygen saturation 99.3% ± 1.1 and 16:8 hours of light:dark photoperiod. 90% of the water was renewed daily and EE2 and DMSO concentrations were adjusted after that.
Project description:The objective of this project was to investigate the impacts of oil exposure in combination with environmental stressors on gene expression in developing C. variegatus.
