Rivers containing effluents from water treatment plants are complex soups of compounds, ranging from pharmaceuticals to natural hormones. Male fathead minnows (Pimephales promelas) were exposed for 3 weeks to effluent waters from the Metropolitan Wastewater Treatment Plant in St. Paul, MN. Fish were tested for their competitive nest holding behavior. Changes in vitellogenin were measured and these were correlated to changes in gene expression using a 22,000 gene microarray developed specifically for fathead minnows. Significant changes in gene expression were observed in both liver and testis, which correlate to phenotypic changes of vitellogenin induction and reduced competitive behavior. We also compared by real-time PCR the expression changes in key genes related to steroid biosynthesis and metabolism in fish exposed to the effluent as well as in fish exposed to a model estrogen and a model androgen. While the gene expression signature from effluent-exposed fish shared some elements with estrogen and androgen signatures, overall it was different, underscoring the complexity of compounds present in sewage and their different modes of action.
Bibliographical noteFunding Information:
This work is the result of research sponsored by the Minnesota Sea Grant College Program supported by the NOAA Office of Sea Grant , United States Department of Commerce, under grant No. NA03OAR4170048 to PWS and partially by Sea Grant No. NA03OAR4170048 to NDD. Dr. Ira Adelman and his colleaguesassisted with the development of markers with support from the Minnesota Sea Grant. The U.S. Government is authorized to reproduce and distribute reprints for government purposes, not withstanding any copyright notation that may appear hereon. This paper is journal reprint No. 591 of the Minnesota Sea Grant College Program. This work was also supported by a fellowship from the Spanish Ministry of Sciences and Technology (EX-2004-0986) to NG-R. NDD is an inventor of the microarray technology discussed in this publication and holds equity in EcoArray, Inc., a company commercializing the technology. She may benefit from this technology by receiving royalties and equity growth.
- Fathead minnow