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Apoptosis in Aquatic Larvae as an Assay for the Disruption of Early DevelopmentEPA Grant Number: U916202
Title: Apoptosis in Aquatic Larvae as an Assay for the Disruption of Early Development
Investigators: Vega, Rebecca L.
Institution: Stanford University
EPA Project Officer: Zambrana, Jose
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $135,832
RFA: STAR Graduate Fellowships (2003) Recipients Lists
Research Category: Academic Fellowships , Biology/Life Sciences , Fellowship - Biochemistry, Molecular Biology, Cell Biology, Development Biology, and Genetics
The objective of this research project is to use the predictable appearance of apoptosis in early larval development as a quantitative bioassay for low-level embryological toxicity.
Aquatic larvae are exposed to a variety of biotic and abiotic stresses during development. Variations in water and light conditions, predator and prey abundance, as well as exposure to xenotoxins may contribute to the disruption of embryogenesis. Aquatic organisms have adapted several mechanisms to defend themselves against potentially damaging environmental perturbations. The multidrug transporters, DNA repair systems, detoxification schemes, and heat-shock response are available to combat toxicants in adult homeostasis, but may not be available in the earliest stages of development. Without these protective mechanisms, embryos may develop with damaged cells or damaged DNA. Apoptosis, the main form of programmed cell death in metazoans, may be essential for the destruction of these damaged or abnormal cells in embryogenesis. This form of apoptosis occurs at a predictable time and in a highly reproducible pattern in the development of fish (Danio rerio) and frog (Xenopus laevis). Additionally, this research project has found that apoptosis cannot occur until a specific developmental stage in a marine model organism, the sea urchin, Strongylocentrotus purpuratus. We propose to use the accumulation of apoptotic cells at the midgastrula stage in frogs and late blastula stage in sea urchins as an assay for low-level toxicity. We anticipate that this bioassay will be a highly quantitative approach for delineating the subtle effects that xenobiotics and other anthropogenic contaminants have on development.