PM01 Amphibian Research and Monitoring
Exhibit Hall
8:00 AM - Monday, 10 November 2003
(PM011) Effects of estrogenic chemicals on developing Xenopus laevis –Analysis of gene expression using macroarray–.
Sone, K1, 4, Hinago, M1, 4, Kitayama, A2, Morokuma, J2, Ueno, N2, 3, Watanabe, H1, 4, Iguchi, T1, 3, 4, 1 Okazaki National Research Institutes, Okazaki, Aichi, Japan4 CREST, Japan Science and Technology, Okazaki, Aichi, Japan2 National Institute for Basic Biology, Okazaki, Aichi, Japan3 Graduate University of Advanced Studies, Okazaki, Aichi, Japan
ABSTRACT- Many chemicals released into the environment have capacities to disrupt the systems of normal development. In this work, we investigated the influence of bisphenol-A (BPA) and nonylphenol (NP) on Xenopus laevis at embryonic and larval stages, as a model animal in aquatic environment. Embryos were continually exposed to eight different concentrations of BPA (0.3-6.8 mg/L) or NP (0.2-11.0 mg/L) from stages 6 to 45 (from 3 to 96 hours post fertilization). Reduced length, tail flexure, microcephaly, rudimental gut coiling and edema were observed at 4.4 mg/L BPA and 4.6 mg/L NP, 93 hours of exposure. Furthermore, to clarify the hypersensitive stages of developing X. laevis to these compounds, exposure terms were shortened for 48 hours and divided into 5 different periods in 96 hours after fertilization. Susceptibility against these chemicals were assessed by alternation of body length. Shortening of body length were observed only in the tadpoles exposed to BPA at the earliest term. NP weakly affected in reduction of body length at early stage and markedly effective at later stages. The test results show that the BPA and NP induce abnormality in developing X. laevis , moreover, the stages of embryos sensitive to the chemicals were different. To analyze the functional mechanisms of BPA and NP in induction of morphological changes, we adapted a DNA array technology and identified a series of genes induced or repressed by these chemicals. These finding may provides the important clues to the elucidation of common mechanisms that underlie teratogenic effects of these chemicals.
Key words: estrogenic chemical, Xenopus laevis , teratogenesis, DNA array