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.

Expression and ecdysteroid responsiveness of the nuclear receptors HR3 and E75 in the crustacean Daphnia magna

“…Daphnid embryos were evaluated at six stages of development (as described by (Kast-Hutcheson et al, 2001)) for relative levels of HR3 and E75 mRNA. HR3 mRNA levels were greatest early in embryo development and significantly declined to approximately 30% of maximum levels by stage 4 (Fig.…”

“…Embryos of developmental stages 1 through 6 (Kast-Hutcheson et al, 2001) were excised from the brood chamber of maternal organisms and combined to yield approximately 350 embryos of each developmental stage. These embryo pools represented the combined broods of 15–20 maternal organisms.…”

Polystyrene nanoplastics inhibit reproduction and induce abnormal embryonic development in the freshwater crustacean Daphnia galeata

“… 47 and Kast-Hutcheson et al . 48 Embryos in the second developmental stage (gastrulation) were isolated from the parent generation after 5 days of exposure. The pregnant adults were prepared on a glass slide with a small quantity of MHW, and using two 25 G needles, embryos were carefully removed from the brood chamber.…”

Evoecotoxicology: Environmental Changes and Life Features Development duringthe Evolutionary Process—the Record of the Past at DevelopmentalStages of Living Organisms

“…From the evoecotoxicologic perspective, these major up and down episodes in environmental stress conditions should be reflected in the ontogeny of living organisms. Could the well-documented stage-dependent susceptibility to physicochemical agents during developmental stages ( Degitz et al 2000 ; Fort et al 2004 ; Greulich and Pflugmacher 2003 ; Herkovits and Fernandez 1979 ; Herkovits et al 1997 ; Kast-Hutcheson et al 2001 ; Rutledge 1997 ) provide a second major link between ontogenesis and the adaptation of life forms to their environment? The high resistance at the blastula stage to physicochemical stress ( Herkovits et al 1997 ; Pérez-Coll and Herkovits 1996 ), enhanced in free-living embryos by protective barriers such as the vitelline membrane and jelly coats, provides support for the argument that this stage reflects very aggressive environmental conditions during the evolution of early multicellular organisms.…”