The Fungicide Propiconazole Interferes With Embryonic Development of the Crustacean Daphnia Magna

Abstract

Propiconazole is a fungicide used in a variety of agricultural applications. Preliminary studies had suggested that embryos of the crustacean Daphnia magna are particularly susceptible to the toxicity of this chemical. The goals of the present study were to define endpoints of daphnid embryonic development that could be routinely used to assess the embryo toxicity of chemicals and to characterize definitively the embryo toxicity of propiconazole to daphnids. Daphnid embryonic development was characterized into six readily distinguishable stages based on the degree of tissue differentiation. Embryonic development could be monitored either in the brood chamber of the maternal organism or using embryos removed from the brood chamber and incubated ex vivo. Standard toxicity assessment revealed that propiconazole elicited no significant adverse effects on daphnid survival or fecundity during a 21-d exposure to concentrations as high as 0.25 mg/L. Exposure to 0.25 mg/L propiconazole, however, caused a significant incidence of developmental abnormalities and embryonic death. Abnormalities were consistent with developmental arrest at later stages of embryonic maturation. Propiconazole elicited a steep concentration-response curve with respect to embryo toxicity, with a 10% and a 90% incidence of embryo toxicity measured at 0.50 and 0.82 mg/L, respectively. Direct exposure of embryos to propiconazole resulted in toxicity, though the incidence and characteristics of developmental abnormalities were not consistent with that observed during chronic exposures. However, maternal exposure to propiconazole followed by transfer of early embryos to propiconazole-free media resulted in embryo toxicity consistent with that observed during chronic exposure. These results indicate that propiconazole interferes with the later stages of daphnid embryonic development, and that this toxicity is manifested largely via maternal exposure to the fungicide.

Crustacean Molting: Regulation and Effects of Environmental Toxicants

“…Several studies have reported effects of environmental chemicals that are consistent with interference with ecdysteroid signaling, though a precise mechanism of action was not established. The chemicals 4-nonylphenol [69], propiconazole [70], and bisphenol A [71], have elicited effects in crustaceans consistent with anti-ecdysteroidal activity. The fungicides propiconazole [72] and fenarimol [73] inhibit cytochromeP450 (CYP) enzymes that are critical to ecdysteroid synthesis.…”

Predictive value of cell assays for developmental toxicity and embryotoxicity of conazole fungicides

“…Additionally, severe abnormalities including abnormally shaped otic vesicle and head length were concentration-related and observed in rat embryos exposed to 10-100 µM ketoconazole (Menegola et al, 2006;Bechter and Schmid, 1987;Kucera et al, 1993). Also, propiconazole interfered with embryonic development of the crustacean Daphnia magna (Kast-Hutcheson et al, 2001). In a study by de Jong et al (2011) comparing EST, rat WEC, and the Zebrafish Embryotoxicity Test (ZET), six related triazole compounds inhibited cardiomyocyte differentiation concentration-dependently in eSt.…”

Mitigating with macrophytes: Submersed plants reduce the toxicity of pesticide‐contaminated water to zooplankton

“…This large batch of working solution provided a sufficient volume for dosing each appropriate test system, plus provided two additional jars for malathion concentration analysis. Although we did not perform a control for the ethanol carrier in this experiment, other experiments have documented no adverse effects of ethanol at concentrations (0.5 ml ethanol/L water) higher than those used in our study (0.41 ml ethanol/L water) on Daphnia [33]. We used a separate container to make each working solution.…”