Meeting Abstract
129.3 Tuesday, Jan. 7 14:00 Fine Time-scale Observation of Development following Cryptobiosis yields a non-conventional Model for Toxicology COVI, JA; University of North Carolina at Wilmington covij@uncw.edu
Embryos of some micro-crustaceans survive decades to centuries of continuous anoxia by reversibly arresting metabolic and developmental processes. While the ecological and evolutionary implications of these cryptobiotic ‘egg banks’ are active topics of study, the impact of environmental pollutants on dormancy, resumption of development, and early hatching events remains uncharacterized. Lipophilic compounds readily pass through arthropod cuticular barriers. Given that this is the primary permeability barrier for invertebrate embryos, and that dormant invertebrate embryos lack the metabolic capacity to deal with chemical loads, it is possible that these embryos will display bioaccumulation of toxins that are otherwise short lived in larvae and adults. Thus, prolonged exposure to low levels of pesticides during periods of obligate dormancy could adversely affect the long-term viability of a population even when titers in the surrounding water are permissive for the larvae or adults. We propose that the long-term susceptibility of micro-crustacean populations to lipophilic toxins is dependent upon both their reliance on a dormant embryonic stage and the permeability of its embryos to lipophilic chemicals. The brine shrimp, Artemia franciscana was developed as a model system to address this hypothesis. A detailed study of early development in encysted A. franciscana embryos was conducted using light microscopy. Classic morphologies associated with “normal” and “abnormal” development were observed and placed in clear developmental sequences that include newly identified characteristics of early development. A novel model of divergent and convergent paths in early development of encysted A. franciscana embryos was generated. An introduction to toxicological tests using this reference model will be presented.
