Identifier

etd-11262012-110801

Degree

Master of Science (MS)

Department

Biological Sciences

Document Type

Thesis

Abstract

Almost five million barrels of south Louisiana crude oil were released into the environment following the explosion of the Deepwater Horizon oil platform on April 20, 2010, however, little is known of the effects of the spill to native species of the northern Gulf of Mexico. Field studies provide a context for ecological realism but laboratory- based studies can connect the specific cause to a specific biological response. A previous field study, completed in 2010, tracked genome expression responses in native killifish resident in oiled and several non-oiled marshes in the northern Gulf of Mexico. Those data suggested significant biological effects from contaminating oil. As a post hoc companion to field studies, we sought to determine the genome expression response of the same native killifish to oil under controlled laboratory conditions to directly link a causal agent to a specific biological response. A concentration response experiment was conducted using experimentally-weathered surrogate oil to further characterize the genome transcriptional response, and to test for additional impacts on health. Transcriptome-wide gene expression responses were determined from the gill and liver tissues of fish exposed to experimentally weathered surrogate oil across a range of concentrations and throughout a time-course of exposure. Transcriptional responses to oil in the laboratory were predictive of the transcriptional response observed in the field study that coincided with the timing and location of oil contamination. These responses included increased expression in the genes activated by the aryl hydrocarbon receptor signaling pathway, including phase 1 and phase 2 metabolism genes, among others. Additionally, network and pathway analyses implicated the effects of transcription, centrosome, cell cycle progression, RNA processing, DNA damage, and apoptosis on gene regulation. These genome expression profiles offer additional scope for interpreting genome expression responses observed in the field, and offer additional insight into consequences of oil exposures in this important native Gulf of Mexico coast species.

Date

2012

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Whitehead, Andrew

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