title: Analysis of gene expression in Homarus americanus larvae exposed to sublethal concentrations of endosulfan during metamorphosis.
abstract: Agricultural pesticide runoff has been suspected as the cause of numerous fish kills in rivers throughout Prince Edward Island but the impact on the surrounding marine environment is unknown. Endosulfan, an organochlorine pesticide, is a potent neurotoxin and molt inhibitor used to combat the Colorado potato beetle however it has the potential to affect non-target organisms including the American lobster (Homarus americanus). Metamorphosis is a critical stage of development and the effects of contaminant exposure during this time are largely unknown in lobster. A 14day endosulfan exposure was performed to identify the effects on survival, development and gene expression in lobster larvae during metamorphosis; all of which were predicted to be negatively impacted. The higher endosulfan concentrations resulted in greater mortality and a significant increase in the number of days required to reach metamorphosis in surviving animals. A custom made H. americanus microarray was used for monitoring the changes in expression of 14,592 genes at the termination of the exposure. Genes with >1.5 fold change and identified as being significant at p<0.05 using one-way ANOVA were selected for further analysis. A total of 707 genes were identified as being significantly differentiated, however with only ~40% annotation of the array, the majority of these genes were unknown. Annotated genes of interest were involved in many processes: development, metabolism, immunity and oxidative stress response and gene regulation. Nine genes of interest (histone H1, farnesoic acid O-methyltransferase, cuticle protein, glutathione S-transferase, thioredoxin, NADH dehydrogenase, ecdysone nuclear receptor Fushi tarazu F1 (FTZ-F1), ferritin and ecdysone inducible protein E75 (EIP-E75)) were selected for RT-qPCR validation of the microarray results. The RT-qPCR method was more sensitive than the microarray yet detected similar expression patterns. The two highest endosulfan concentrations resulted in increased mortalities, developmental delays in reaching metamorphosis and significant changes in gene expression. This research provides a foundation for using microarray gene expression profiles as screening tools for exploring the impact of environmental contaminants on lobster.
authors.affiliation: Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave, Charlottetown, PE C1A 4P3, Canada; AVC Lobster Science Centre, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave, Charlottetown, PE C1A 4P3, Canada; Atlantic Laboratory for Environmental Testing, Environment Canada, P.O. Box 23005 443 University Ave, Moncton, NB E1A 3E9, Canada. Electronic address: megan.bauer@ec.gc.ca.
authors.forename: Megan
authors.initials: M
authors.lastname: Bauer
authors.forename: Spencer J
authors.initials: SJ
authors.lastname: Greenwood
authors.forename: K Fraser
authors.initials: KF
authors.lastname: Clark
authors.forename: Paula
authors.initials: P
authors.lastname: Jackman
authors.forename: Wayne
authors.initials: W
authors.lastname: Fairchild
mesh_terms: D000818:Animals; D004726:Endosulfan / Q000633:toxicity*; D018507:Gene Expression Regulation, Developmental; D007814:Larva / Q000187:drug effects; D008675:Metamorphosis, Biological / Q000187:drug effects*; D058977:Molecular Sequence Annotation; D008121:Nephropidae / Q000235:genetics* / Q000378:metabolism; D040081:Protein Array Analysis; D059467:Transcriptome / Q000187:drug effects; D014877:Water Pollution, Chemical
chemical_list: D004726:Endosulfan
keywords: Endosulfan; H. americanus; Microarray; Toxicogenomics