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Ingestion of microcystins by Daphnia : Intestinal uptake and toxic effects
Author(s) -
Rohrlack Thomas,
Christoffersen Kirsten,
Dittmann Elke,
Nogueira Isabel,
Vasconcelos Vitor,
Börner Thomas
Publication year - 2005
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2005.50.2.0440
Subject(s) - ingestion , biology , microcystin , daphnia , microcystis , midgut , foregut , daphnia magna , microcystis aeruginosa , daphnia galeata , toxicity , physiology , endocrinology , medicine , cladocera , cyanobacteria , anatomy , botany , ecology , branchiopoda , zooplankton , larva , bacteria , genetics
We investigated the intestinal uptake and adverse effects of microcystins ingested with Microcystis on Daphnia galeata . The gut structure, blood microcystin concentration, appearance, and movements of Daphnia fed Microcystis PCC 7806 or a microcystin‐deficient PCC 7806 mutant were monitored over time. Microcystins were rapidly taken up from the digestive cavity into the blood. This process apparently required a preceding disruption of the gut epithelium by an as‐yet‐unknown Microcystis factor. Once microcystins entered the blood, they affected the neuromuscular communication or another life function that influences major muscle systems. Consequently, the beat rates of the thoracic legs, mandibles, and second antennae as well as the activity of the foregut decreased, whereas the midgut muscles were stimulated. Finally, the animals exhibited symptoms of exhaustion and died. The present results suggest that an ingestion of between 10.2 ng and 18.3 ng of microcystin per 1 mg of Daphnia body fresh weight is sufficient to kill D. galeata within 2 d.