Meeting Abstract

62.5  Tuesday, Jan. 6  Disruption of tissue morphogenesis in pesticide-exposed Xenopus laevis tadpoles LENKOWSKI, J.R.**; MCLAUGHLIN, K.M.; Tufts Univ., Medford, MA jenny.lenkowski@tufts.edu

A countless number of anthropogenic chemicals are released into the environment every day without a full understanding of how they may affect non-target organisms. One such chemical is the widely used herbicide atrazine. Atrazine was originally designed to inhibit photosynthesis in weeds, but has since been implicated as a contributing factor to anomalies in development and reproductive systems observed in wild and laboratory amphibian populations. As amphibians are particularly sensitive to environmental contaminants due to their use of both aquatic and terrestrial habitats, studies have continued to use amphibians to examine the effects of environmental contaminants. We have previously described increased malformations and apoptosis following acute atrazine exposure during the specific developmental window of organ morphogenesis in the model species Xenopus laevis. In our laboratory studies we are now further examining the effects of atrazine exposure during these stages on the morphogenesis of muscle and cartilage, as well as expression of matrix metalloproteinases (MMP) that degrade the extracellular matrix. We have found muscle degradation in the tail and gut of malformed animals using an acute atrazine exposure. In addition, misregulation of the thyroid-hormone regulated MMP, MMP18, occurs as quickly as 24 hours after the start of exposure. In order to extend these findings, we hope to determine the dose response and timing of these effects. Our results begin to explain how atrazine can affect processes that are important for organ morphogenesis during amphibian development which have not been thoroughly examined in previous studies. Importantly, our studies further demonstrate the importance of characterizing teratogenic effects of environmental chemicals at many stages of development using multiple experimental strategies