Biomarker in der Umweltprobenbank (Biomarkers in samples of German environmental specimen bank)
Björn Seidel, Andrea Wenzel, Matthias Teigeler
Fraunhofer-Institut für Molekularbiologie und Angewandte Oekologie (Fraunhofer-IME) Bereich: Angewandte Oekologie, Schmallenberg
Several recent publications and conferences indicate an increasing implementation of molecular biomarkers for the identification of environmental stressors in biota samples. For this feasibility study we investigated the potential use of molecular biomarkers in samples of the German environmental specimen bank (ESB). We performed investigations with archived muscle and liver tissue samples of bream (Abramis brama). On the one hand bream were chosen because this fish species is sampled for the ESB program for a long period. On the other hand fish are exposed to a high number of pollutants in the aquatic environment so that there is a large potential for applications. Furthermore, a huge amount of genetic data from laboratory investigations of fish is available. We identified distinct gene markers regulated in bream by different stressors via gene sequence comparison with zebra fish (Danio rerio), a species related to the bream. It was possible to detect gene markers which are expressed in an agent-specific or agent-unspecific way. HSP (heat shock protein) is up-regulated agentunspecifically by a number of stressors and can be used as a general health indicator. Agent-specific genes like those for Metallothionein and Vitellogenin are strongly regulated by heavy metals and endocrine disrupters, respectively. For these genes we could show that the activity in bream liver depends on the exposure conditions. Fish caught at sites with higher pollutant levels had a higher expression of the respective genes as compared to fish from a reference site. Our analyses support the use of molecular biomarkers in bream samples of the ESB for retrospective monitoring. By applying the DNA-microarray technique it now is even possible to expand the investigations to a large number of relevant genes and high number of samples. By this means we would be able to supplement the successful retrospective monitoring studies on the exposure of fish towards pollutants with data to possible effects on a genetic level. Since biomarkers may respond sex-specifically (e. g. Vitellogenin) we recommend a separate sampling and archiving of male and female organisms (especially for bream) to increase the range of applications.