Title: Relationships among DNA adducts, micronuclei, and fitness parameters in Xenopus laevis exposed to benzo[a]pyrene
Abstract: We investigated whether hepatic DNA adducts, erythrocytic micronuclei, wet weight, developmental stage, wet weight at metamorphosis, and time to metamorphosis changed in larval Xenopus laevis exposed to varied doses of benzo[a]pyrene (B[a]P). Using 32P-postlabeling, we observed relative DNA adduct levels of 0 to 13.7 × 10−7 following continuous exposure to 0 to 496 nM B[a]P for 12 days and relative levels of 0 to 10 × 10−7 after exposure to 248 nM B[a]P over a range of 0 to 16 days. Mean numbers of micronuclei were 1.7, 6.3, and 16.41000 red blood cells after exposure to 0, 31, and 248 nM B[a]P, respectively, for 14 days. Micronuclei also ranged from 1.3 to 120.51000 red blood cells following exposure to 248 nM B[a]P over a range of 0 to 16 days. Comparatively, levels of both DNA adducts and micronuclei were greatly reduced in animals exposed previously to 31 and 248 nM B[a]P, but assayed at metamorphosis. Larvae exposed to 248 nM B[a]P for 14 days took approximately 4 days longer to metamorphose than unexposed larvae. This increased time to metamorphosis was associated with increased DNA adducts and micronuclei in larvae exposed to 248 nM B[a]P. However, DNA adducts and micronuclei also increased in larvae exposed to 31 nM B[a]P, while time to metamorphosis did not. Larval wet weight was reduced by as much as 44% immediately following exposure to B[a]P. However, there was no effect of exposure on wet weight at metamorphosis. Exposed animals were up to 2 developmental stages younger than unexposed animals in one experiment, but differences among exposed and unexposed animals were less distinct in a second experiment. These studies suggest that DNA adducts and micronuclei can be sensitive measures of sublethal DNA damage, as well as possible short-term indicators of indirect effects on fitness in amphibians.
Publication Year: 1995
Publication Date: 1995-07-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 21
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