Sures Bernd, Dezfuli Bahram S, Krug Harald F
Zoologisches Institut I Okologie-Parasitologie, Universität Karlsruhe, Kornblumenstrasse 13, D-76128 Karlsruhe, Germany.
Int J Parasitol. 2003 Dec;33(14):1617-22. doi: 10.1016/s0020-7519(03)00251-0.
Uninfected chub as well as fish experimentally infected with the acanthocephalan parasite Pomphorhynchus laevis were exposed to (210)Pb(2+) for up to 38 days and the uptake and distribution of lead within different fish organs and the parasites was determined at various time points. Highest metal concentrations were detected in the acanthocephalans, followed by intestine, bile, liver, gill and muscle of the fish host. Infected chub had significantly lower (210)Pb levels in the gills on day 17 (P< or =0.01), in the bile on day 24 (P< or =0.05) and in the gills as well as in the intestine on day 38 compared with uninfected fish. A subsequent polynomial regression revealed that lead levels for the infected fish ranged below the levels determined for uninfected fish during most of the exposure period. This is the first proof that P. laevis reduces lead levels in the bile thereby diminishing or even impeding the hepatic intestinal cycling of lead, which may reduce the amount of metals available for the fish organs. This is especially important for ecotoxicological research. For example, organisms used as accumulation indicators may erroneously indicate low levels of pollution if they are infected with parasites which alter their pollutant uptake mechanisms. Additionally, the results gave further experimental evidence for acanthocephalans as accumulation indicators for metals.
将未感染的白鲑以及经棘头虫寄生虫平滑泡吻棘头虫实验感染的鱼类暴露于（210）Pb（2 +）长达38天，并在不同时间点测定铅在不同鱼器官和寄生虫内的摄取和分布。在棘头虫中检测到最高的金属浓度，其次是鱼宿主的肠、胆汁、肝脏、鳃和肌肉。与未感染的鱼相比，感染的白鲑在第17天鳃中的（210）Pb水平显著较低（P≤0.01），在第24天胆汁中的（210）Pb水平显著较低（P≤0.05），在第38天鳃和肠中的（210）Pb水平也显著较低。随后的多项式回归显示，在大部分暴露期内，感染鱼的铅水平低于未感染鱼的铅水平。这是首次证明平滑泡吻棘头虫可降低胆汁中的铅水平，从而减少或甚至阻碍铅的肝肠循环，这可能会减少鱼器官可利用的金属量。这对生态毒理学研究尤为重要。例如，如果用作积累指标的生物感染了改变其污染物摄取机制的寄生虫，它们可能会错误地指示低污染水平。此外，这些结果为棘头虫作为金属积累指标提供了进一步的实验证据。
