Species, tissue and gender-related organochlorine bioaccumulation in white-sided dolphins, pilot whales and their common prey in the northwest Atlantic.

Organochlorine concentrations were measured in white-sided dolphins, pilot whales, and their prey from the Gulf of Maine and used to identify species, tissue, and gender differences, and trophic transfer trends, in bioaccumulation. Polychlorinated biphenyl concentrations ([PCB]) in dolphin blubber (13 +/- 7.1 micrograms/g fresh wt.) were twice those in pilot whales, but pesticide concentrations (20 +/- 13 micrograms/g fresh) were similar between species. 4,4'-DDE, trans-non-achlor, Cl6(153) and Cl6(138) concentrations were highest. Skin tissues had more recalcitrant organochlorines than the internal organs. Male dolphins bioaccumulated higher concentrations of nonmetabolizable PCBs and hexachlorocyclohexane (HCH) isomers, whereas pilot whales had no gender-related differences in bioaccumulation. Pilot whales, mackerel, and herring had proportionately higher concentrations of DDTs, whereas [PCB] were higher in dolphins and squid. Although these odontocetes feed at the same trophic level and store a similar suite of contaminants, dolphins bioaccumulated higher and potentially hazardous 4,4'-DDE and PCB concentrations from food in their more geographically restricted range.

Effects of protein and juglone on gypsy moths: Growth performance and detoxification enzyme activity.

The individual and interactive effects of dietary protein and juglone on larval performance and midgut detoxification enxymes were investigated for the gypsy moth,Lymantria dispar. The experimental design was a 2 × 3 factorial, with two levels of protein and three levels of juglone. We monitored survival/development rates from egg hatch to pupation and conducted fourth-instar feeding trials for determination of nutritional indices. Enzyme solutions were prepared from midguts of fifth instars and assayed for polysubstrate monooxygenase, esterase, quinone reductase, and glutathione transferase activities. Results showed that low protein levels prolonged development times, increased consumption rates, and reduced pupal weights. Juglone markedly reduced survival, growth, and consumption rates, increased development times, and reduced pupal weights. The interaction between protein and juglone influenced larval digestion efficiencies and female pupal weights. Polysubstrate monooxygenase activities were unaffected by diet, whereas esterase activities increased in response to both low dietary protein and presence of juglone. Low protein levels increased soluble quinone reductase activities but decreased glutathione transferase activities. Glutathione transferase activities were lowest in larvae fed low-protein, high-juglone diets and may have contributed to the especially poor performance of larvae on those diets. Quinone reductase and glutathione transferase are the systems of importance in detoxification of juglone, and moderate to low activities of these enzymes may explain why gypsy moths perform poorly on members of the Juglandaceae.