Long-Term Pyrene Exposure of Grass Shrimp, Palaemonetes pugio, Affects Molting and Reproduction of Exposed Males and Offspring of Exposed Females

Abstract

The objective ofthis study was to investigate the impact oflong-term pyrene exposure on molting and reproduction in the model estuarine invertebrate, the grass shrimp (Palaemonetes pugto).Grass shrimp were exosed to measured concentrations of 5.1, 15.0, and 63.4 ppb (pg/L) pyrene for 6 wedss, during which time we determined molting and survivorship. At the end of the exposure, we immediately sacrificed some of the shrimp for biomarker (CYP1A and vitellin) analyses.The remaining shrimp were used to analyze fecundity and embryp survivorship during an additional 6 weeks after termination of pyrene exposure. Male shrimp at the highest pyrene dose (63 ppb) experienced a significant delay in molting and in time until reproduction, and showed elevated ethoxycoumarin o-deethylase (ECOD) activity immediately after the 6-week exposure period. In contrast, 63 ppb pyrene did not affect these parameters in female shrimp. Females produced the same number of eggs per body weight, with high egg viability (98-100%) at all exposure levels, but with decreased survival for the offspring ofthe 63-ppb pyrene-exposed females. In addition, vitellin levels were elevated only in females at 63 ppb pyrene after the 6-week exposure. We hypothesize that the elewted vitellin binds pyrene and keeps it biologically unavailable to adult females, resulting in materal transfer ofpyrene to the embryos. This would account for the lack of effect of pyrene exposure on ECOD activity, molting, and reproduction in the adult females, and for reduced survival of their offspring.

Impacts of cyclic hypoxia on reproductive and gene expression patterns in the grass shrimp: field versus laboratory comparison

“…The wild shrimp in the current study were collected in August, 4 or 5 months into their reproductive season; thus, the fecundity values do not represent their first brood of the season which may explain why a significant difference in relative fecundity among sites was not observed in East Bay. Furthermore, fecundity may not be the best indicator of exposure to natural or anthropogenic compounds in grass shrimp; females exposed to pyrene (Oberdorster et al 2000), mercury and PCBs (Wall et al 2001), the insecticide endosulfan (Wirth et al 2002) and the pesticides chloropyrifos and fipronil (Volz et al 2003) in the laboratory did not show a reduction in fecundity compared to controls.…”

Freshwater shrimp (Palaemonetes australis) as a potential bioindicator of crustacean health

“…Gender-specific induction of ECOD was detected by Oberdorster et al (2000a) in P. pugio when exposed to pyrene at 63 ppb. In that study, pyrene induced ECOD activity in males only.…”

“…Although the life cycle of P. australis has been poorly studied in estuaries of southwest Western Australia, this study found it to be easily maintained in the laboratory, making it an ideal candidate for the study of the impact of contaminant exposure on the health of this estuarine decapod species. PAHs have been shown to significantly induce CYP1A-like protein (P450) activity in grass shrimp (P. pugio) as measured by ECOD in hepatopancreatic extracts (Oberdorster et al 2000a). Investigations elsewhere have indicated that blue crabs (Callinectes sapidus) were unable to metabolize and eliminate PAHs the closer they were to molting, resulting in a higher body burden (Mothershead and Hale 1992).…”

“…Investigations elsewhere have indicated that blue crabs (Callinectes sapidus) were unable to metabolize and eliminate PAHs the closer they were to molting, resulting in a higher body burden (Mothershead and Hale 1992). PAHs have also been shown to delay molting by P. pugio males (Oberdorster et al 2000a) and the blue crab (Mothershead and Hale 1992). This is believed to be due to competition for substrates by cytochrome P450s needed to metabolize ecdysone for the molt (Mothershead and Hale 1992;Oberdorster et al 2000a).…”

“…PAHs have also been shown to delay molting by P. pugio males (Oberdorster et al 2000a) and the blue crab (Mothershead and Hale 1992). This is believed to be due to competition for substrates by cytochrome P450s needed to metabolize ecdysone for the molt (Mothershead and Hale 1992;Oberdorster et al 2000a). In our study, P. australis exposed to 0.01, 0.1, and 1 ppm B[a]P, had a significantly elevated ECOD activity which increased with each concentration of B[a]P. This clearly demonstrated that molting was not a confounding factor in the interpretation of the response of cytochrome P450 detoxification in the shrimp to B[a]P exposure in this study.…”