Why Amphibians Are More Sensitive than Mammals to Xenobiotics

Quaranta, Angelo; Bellantuono, Vito; Cassano, Giuseppe; Lippe, C

doi:10.1371/journal.pone.0007699

Cited by 129 publications

(97 citation statements)

References 27 publications

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“…The negative impacts on wild amphibians is especially concerning given that the dose examined here (2.5 ppb) is in the range that animals experience year-round in areas where atrazine is used (1,32,46), well within levels found in rainfall (47), in which levels can exceed 100 ppb in the midwestern United States (48), and below the current US Environmental Protection Agency drinking water standard of 3 ppb (49). Furthermore, recent studies have shown that frog skin absorbs atrazine at much higher rates than the skin of mammals (50), and even semiterrestrial frog species take up significant amounts of atrazine (51). Thus, the exposure level examined in the present study is relevant even to semiterrestrial amphibians.…”

Section: Discussionmentioning

confidence: 99%

Atrazine induces complete feminization and chemical castration in male African clawed frogs (Xenopus laevis)

Hayes

Khoury

Narayan

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

525

307

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The herbicide atrazine is one of the most commonly applied pesticides in the world. As a result, atrazine is the most commonly detected pesticide contaminant of ground, surface, and drinking water. Atrazine is also a potent endocrine disruptor that is active at low, ecologically relevant concentrations. Previous studies showed that atrazine adversely affects amphibian larval development. The present study demonstrates the reproductive consequences of atrazine exposure in adult amphibians. Atrazineexposed males were both demasculinized (chemically castrated) and completely feminized as adults. Ten percent of the exposed genetic males developed into functional females that copulated with unexposed males and produced viable eggs. Atrazineexposed males suffered from depressed testosterone, decreased breeding gland size, demasculinized/feminized laryngeal development, suppressed mating behavior, reduced spermatogenesis, and decreased fertility. These data are consistent with effects of atrazine observed in other vertebrate classes. The present findings exemplify the role that atrazine and other endocrine-disrupting pesticides likely play in global amphibian declines.A trazine is one of the most widely used pesticides in the world. Approximately 80 million pounds are applied annually in the United States alone, and atrazine is the most common pesticide contaminant of ground and surface water (1). Atrazine can be transported more than 1,000 km from the point of application via rainfall and, as a result, contaminates otherwise pristine habitats, even in remote areas where it is not used (2, 3). In fact, more than a half million pounds of atrazine are precipitated in rainfall each year in the United States (2).In addition to its persistence, mobility, and widespread contamination of water, atrazine is also a concern because several studies have shown that atrazine is a potent endocrine disruptor active in the ppb (parts per billion) range in fish (4, 5), amphibians (6-12), reptiles, and human cell lines (5, 13-15), and at higher doses (ppm) in reptiles (16-18), birds (19), and laboratory rodents (20-28). Atrazine seems to be most potent in amphibians, where it is active at levels as low as 0.1 ppb (6-10). Although a few studies suggest that atrazine has no effect on amphibians under certain laboratory conditions (29,30), in other studies, atrazine reduces testicular volume; reduces germ cell and Sertoli cell numbers (11); induces hermaphroditism (6, 8, 10); reduces testosterone (10); and induces testicular oogenesis (7-9, 31). Furthermore, atrazine contamination is associated with demasculinization and feminization of amphibians in agricultural areas where atrazine is used (32) and directly correlated with atrazine contamination in the wild (7,9,33,34).Despite the wealth of data from larvae and newly metamorphosed amphibians, the ultimate impacts of atrazine's developmental effects on reproductive function and fitness at sexual maturity, which relate more closely to population level effects and amphibian declines, have b...

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Section: Discussionmentioning

confidence: 99%

Atrazine induces complete feminization and chemical castration in male African clawed frogs (Xenopus laevis)

Hayes

Khoury

Narayan

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

525

307

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“…26) By applying this method to the ventral skin of adult Rana esculenta, the linear correlation between log P e (permeation coefficients) and log K ow was confirmed for five chemicals. 30) Therefore, the observed discrepancy in the correlation of absorption parameters with log K ow may originate from the different application method of pesticides, i.e., solid deposit or aqueous solution.…”

Section: )mentioning

confidence: 99%

Bioconcentration and metabolism of pesticides and industrial chemicals in the frog

Katagi

Ose

2014

J. Pestic. Sci.

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Exposure to pesticide residues is claimed to be one of the possible causes of frog decline. Knowledge of basic information on the uptake, metabolism and depuration processes of pesticides in the frog is needed to understand the relationship between exposure and toxic effects from their actual body burden, together with their bioconcentration. The hydrophobicity of pesticides and industrial chemicals was one of the most important factors controlling bioconcentration, similarly to fish, when frogs are exposed to contaminated water. Skin absorption was also a key route in the uptake process especially in the adult frog. The metabolic profiles in the frog, mainly examined by an intraperitoneal injection technique, were common to other aquatic species without any frog-specific transformation reaction. The effects of developmental stage, sex, species and environmental factors such as temperature were observed for bioconcentration and metabolism.

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“…Amphibians are excellent indicators of environmental quality because their permeable skin allows for exchange of materials with the surrounding environment (Quaranta et al 2009). The combination of multiple stressors, such as rising temperatures, environmental degradation, and shifting ecosystem dynamics, can lead to greater stress and negative consequences for amphibian populations.…”

Section: Introductionmentioning

confidence: 99%

Thrice as easy to catch! Copper and temperature modulate predator‐prey interactions in larval dragonflies and anurans

Hayden

Reeves

Holyoak³

et al. 2015

Ecosphere

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Abstract. Amphibians are important indicators of environmental health, and their populations are in worldwide decline. The causes of these declines are diverse and not well understood. In some cases multiple stressors and complex causal mechanisms have been identified. Experimental studies have shown that contaminants can cause the failure of Lithobates sylvaticus tadpoles to initiate predator avoidance behaviors, potentially leading to increased tadpole capture and injury. Copper is a contaminant known to negatively affect amphibians and other aquatic organisms at sub-lethal levels. Mining waste, certain pesticides, vehicle exhaust and brake pad dust are sources of copper, which can enter hydrologic systems through runoff. Additionally, temperature is known to influence predator-prey interactions of ectotherms and is predicted to rise in some areas as climate changes. We examined how copper and temperature affected behavior and predation dynamics between an odonate predator (Aeshna sitchensis) and larval L. sylvaticus prey. We found that sublethal concentrations of copper near the analytical detection limits for this element (1.85 lg Cu/L) significantly reduced tadpole and odonate activity. Above-average temperatures (228C) significantly increased tadpole activity and decreased dragonfly activity, compared with ambienttemperature treatments (178C). These behavioral responses culminated in an approximately three-fold increase in the number of dragonfly attacks on tadpoles in the elevated-temperature, copper-exposed treatments. We suggest that increased concentrations of dissolved copper and elevated water temperatures are harmful to amphibian prey through maladaptive behavioral responses in the presence of predators.

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Why Amphibians Are More Sensitive than Mammals to Xenobiotics

Cited by 129 publications

References 27 publications

Atrazine induces complete feminization and chemical castration in male African clawed frogs (Xenopus laevis)

Atrazine induces complete feminization and chemical castration in male African clawed frogs (Xenopus laevis)

Bioconcentration and metabolism of pesticides and industrial chemicals in the frog

Thrice as easy to catch! Copper and temperature modulate predator‐prey interactions in larval dragonflies and anurans

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