ABSTRACT
This chapter examines biochemical aspects of ecotoxicology with the dual goals of understanding toxicant mode of action and describing molecular biomarkers. A variety of biochemical processes can transform a xenobiotic present in the cell. The overarching theme to these transformations is either to render the xenobiotic more amenable to further reaction or to make it more easily eliminated from the cell. While numerous studies have thoroughly characterized the diverse Cytochromes P-450 and their regulation in mammals, comparatively little is known about the transcriptional mechanism taking place in aquatic invertebrates. Understanding molecular effects enhances the ability to assign causal linkage to effects at higher levels of organization and to predict effects of untested chemicals based on similar molecular interactions with biomolecules. Biomarkers emerge from this understanding as tools to proactively measure effects in field situations.
