Altered exoskeleton composition and vitellogenesis in the crustacean Gammarus sp. collected at polluted sites in the Saguenay Fjord, Quebec, Canada.
Gammarus sp. individuals were collected at four intertidal sites subjected to direct sources of pollution (marinas, ferry traffic, and harbors) and at one site with no direct source of pollution. Levels of vitellogenin-like proteins (Vtg), metallothioneins (MT), alkali-labile phosphates (ALPs) in proteins, and lipogenic enzyme activities (i.e., glucose-6-dehydrogenase, isocitrate dehydrogenase, and malate enzyme) were measured in whole soft tissues. In exoskeletons, levels of pH-dependent extractable protein and chitin were determined to assess the possible impacts of pollution on exoskeleton integrity and the molting process. Results show that males were consistently heavier than females regardless of site quality but that the whole-body weight of both sexes was significantly lower at polluted sites. Females displayed either induced or decreased Vtg-like proteins at polluted sites, indicating significant changes in gametogenesis activity. MT levels were not sex dependent and tended to be induced at all impacted sites. ALP levels in acetone-fractionated proteins indicate altered phosphate mobilization at some impacted sites, where females tended to display higher ALP levels. Lipogenic enzyme activities did not vary by sex but were readily increased at impacted sites, suggesting a delay in gonad maturation rates. Exoskeleton protein characteristics revealed that the proportion of chitin in exoskeletons was a lower at most impacted site, suggesting disruption of chitin and pH-dependent protein mobilization. Principal component analysis revealed that gammarids collected at affected sites displayed substantial changes in the proportion of chitin, arthropodin, sclerotin, MTs, and intermediary glucose metabolism (glucose-6-phosphate dehydrogenase, and isocitrate dehydrogenase in soft tissues) and thus suffered from disturbed gametogenesis and exoskeleton integrity.
Gagné
F
F
St. Lawrence Centre, Environment Canada, Research on Aquatic Ecosystems, 105 McGill Street, Montreal, Que., Canada H2Y 2E7. francois.gagne@ec.gc.ca
Blaise
C
C
Pellerin
J
J
D000818:Animals; D001835:Body Weight; D002686:Chitin / Q000378:metabolism; D003445:Crustacea / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D016002:Discriminant Analysis; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D007521:Isocitrate Dehydrogenase / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000378:metabolism; D008297:Male; D008668:Metallothionein / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011792:Quebec; D045483:Rivers; D012737:Sex Factors; D014818:Vitellogenesis / Q000187:drug effects*; D014819:Vitellogenins / Q000096:biosynthesis; D014874:Water Pollutants, Chemical / Q000506:poisoning*
D010710:Phosphates; D011506:Proteins; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; C013247:sclerotin; D002686:Chitin; D008668:Metallothionein; D008291:Malate Dehydrogenase; D007521:Isocitrate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase