The use of Lepidium sativum in a plant bioassay system for the detection of microcystin-LR.
Toxin-producing cyanobacteria pose a worldwide health threat to humans and animals due to their increasing presence in both drinking and recreational waters. Detection of microcystins in water generally relies on specialised equipment and a delay of several days for transport and analysis. Little work has, however, been done on establishing a simple, cost-effective and sensitive plant bioassay for the detection of microcystin-LR (MCLR) in water at the WHO Tolerable Daily Intake guideline level of 1 microg/l. We investigated the effect of a MCLR extract at 1 and 10 microg/l on the growth of Lepidium sativum over 6 days. Exposure to 10 microg/l MCLR resulted in a significant decrease in root and leaf lengths and fresh weights of seedlings when compared to the controls. These results were consistent with seedlings exposed to pure MCLR at 10 microg/l. Seedlings exposed to 1 microg/l MCLR showed a significant decrease in root development from day 2 to day 6. Glutathione S-transferase and glutathione peroxidase activities were also significantly raised in plants from days 5 and 4, respectively, at both toxin levels investigated.
Gehringer
Michelle M
MM
Department of Biochemistry and Microbiology, University of Port Elizabeth, P.O. Box 1600, Port Elizabeth 6000, South Africa. bcammg@upe.ac.za
Kewada
Vijayne
V
Coates
Nadya
N
Downing
Tim G
TG
D000818:Animals; D001427:Bacterial Toxins / Q000008:administration & dosage / Q000494:pharmacology*; D001681:Biological Assay / Q000379:methods; D000458:Cyanobacteria; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D005979:Glutathione Peroxidase / Q000187:drug effects; D005982:Glutathione Transferase / Q000187:drug effects; D031220:Lepidium sativum / Q000187:drug effects*; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic / Q000008:administration & dosage / Q000494:pharmacology*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D018515:Plant Leaves / Q000187:drug effects; D018517:Plant Roots / Q000187:drug effects
D001427:Bacterial Toxins; D004791:Enzyme Inhibitors; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase; D010749:Phosphoprotein Phosphatases; C057862:cyanoginosin LR