Lead

We aim at understanding the occurrence and ecotoxicological effects of selected cyanobacterial toxins and elucidating their uptake and modes of action in fish. The data will contribute to the hazard and risk assessment.

Background

Cyanobacteria have gained worldwide importance as their intense growth in eutrophic surface waters. Microcystis and Planktothrix spp. are most often observed to develop high densities in lake water. These phytoplankton species may produce harmful toxins such as cyclic oligopeptides, however, the biological functions of most cyanobacterial oligopeptides are not known. Microcystin-LR (MC-LR) may have a severe impact on aquatic biota, or even lifestock drinking contaminated water. However, in vivo uptake mechanisms and elimination kinetics of microcystins are poorly understood. Human health problems mainly originate from chronic exposure to low microcystin concentrations in poorly treated drinking water, leading to liver cancer. Cyanopeptolins, another class of cyanobacterial oligopeptides are not investigated for their toxicity. To date, there is a lack of understanding of the uptake kinetics, metabolism and effects of these peptide toxins in fish including their molecular effects.

Aims

The aim of this project is to deepen our understanding on the formation, molecular and cellular effects of these cyanobacterial toxins. Research is promoted by limnologists, environmental toxicologists and chemists focusing on a common research question, thereby investigating multiple aspects including isolation, structural and toxicological characterization, preparation of a series of derivatives to probe the toxicology and mode of action, in particular of cyanopeptolin CP1020 and MC-LR. Uptake through transmembrane transporters, kinetics and molecular and developmental effects will be studied in zebrafish. Following questions will be addressed for a better hazard and risk assessment of these toxins:

What toxin patterns exist in P. rubescens, and what are their chemical structures and toxicity?

How is the uptake, distribution and elimination kinetics of fluorescent MC-LR and CP1020 in zebrafish?

What is the role of uptake transporters (Oatp) and efflux transporters (ABC-transporters) in zebrafish hepatocytes?

What are the molecular effects and mechanisms of action of MC-LR and CP1020 on the transcriptome in zebrafish?

By tackling these questions and by linking limnology, chemistry and ecotoxicology we will provide a unique multidisciplinary training opportunity across multiple areas.