Developmental impact of atrazine on metamorphing Xenopus laevis as revealed by nuclear analysis and morphology

Abstract

Atrazine is one of the major surface water contaminants in the midwestern United States. Speculations have arisen on the potential effects of atrazine contamination to anuran larvae developing in these surface waters. In this study, Xenopus laevis tadpoles were exposed to environmentally relevant concentrations of atrazine. Nuclear and morphological endpoints were used to assess the effects of atrazine on developing X. laevis. Atrazine significantly affected metamorphing X. laevis after three-weeks exposure compared to controls as revealed by flow cytometric nuclear DNA analysis. The flow cytometric analysis was reflective of developmental effects. The number of nuclei per organism also was analyzed. Nuclei number was found to be associated with X. laevis development. Nuclei counting showed significant effects of atrazine after five-weeks exposure. A third endpoint, Nieuwkoop and Faber (NF) morphological staging, also demonstrated that atrazine significantly affected development after four weeks. Atrazine was found to alter the timing of metamorphosis of X. laevis using both nuclear analysis and gross morphology. The NF staging was found to be a sensitive assay to measure effects of development, whereas flow cytometry provided an impartial quantitative measure.

Developmental origins of neurotransmitter and transcriptome alterations in adult female zebrafish exposed to atrazine during embryogenesis

“…Atrazine (ATZ) (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) is a common pre-emergent agricultural herbicide that is a reported endocrine disruptor and is indicated to be a potential carcinogen (Cooper et al 2000; Freeman and Rayburn, 2005; Freeman et al 2011; Wetzel et al 1994). Atrazine has widespread use in the Midwest United States and is used to prevent broad leaf and grassy weeds in corn, sorghum grass, sugar cane, and wheat crops.…”

Atrazine affects kidney and adrenal hormones (AHs) related genes expressions of rare minnow (Gobiocypris rarus)

“…For example, its effects on the reproduction of copepods (Hincapie et al, 2005) and metamorphosis and sex differentiation of Xenopus laevis (Freeman and Rayburn, 2004) were observed. Cooper et al (2000) proved that atrazine could exert influence on the ovarian function in rats through disrupting the neuroendocrine control of HPG axis.…”

The effects of atrazine on spotted salamander embryos and their symbiotic alga

“…Atrazine and other agricultural chemicals are often carried by wind or rainwater to areas far from the original application site, and can remain in soil for well over 6 months and in water for up to one year (Capel and Larson 2001;Hayes et al 2002Hayes et al , 2003Isensee et al 1990;Miller et al 2000;Muller et al 1997;Rohr et al 2004). Atrazine can affect amphibian development, growth, feeding ecology, and susceptibility to disease and parasites (Boone and James 2003;Forson and Storfer 2006a;Freeman and Rayburn 2005;Hayes et al 2002Hayes et al , 2003Kiesecker 2002;Rohr et al 2004).…”