Gene expression profiling to characterize sediment toxicity--a pilot study using Caenorhabditis elegans whole genome microarrays.
BACKGROUND
Traditionally, toxicity of river sediments is assessed using whole sediment tests with benthic organisms. The challenge, however, is the differentiation between multiple effects caused by complex contaminant mixtures and the unspecific toxicity endpoints such as survival, growth or reproduction. The use of gene expression profiling facilitates the identification of transcriptional changes at the molecular level that are specific to the bio-available fraction of pollutants.


RESULTS
In this pilot study, we exposed the nematode Caenorhabditis elegans to three sediments of German rivers with varying (low, medium and high) levels of heavy metal and organic contamination. Beside chemical analysis, three standard bioassays were performed: reproduction of C. elegans, genotoxicity (Comet assay) and endocrine disruption (YES test). Gene expression was profiled using a whole genome DNA-microarray approach to identify overrepresented functional gene categories and derived cellular processes. Disaccharide and glycogen metabolism were found to be affected, whereas further functional pathways, such as oxidative phosphorylation, ribosome biogenesis, metabolism of xenobiotics, aging and several developmental processes were found to be differentially regulated only in response to the most contaminated sediment.


CONCLUSIONS
This study demonstrates how ecotoxicogenomics can identify transcriptional responses in complex mixture scenarios to distinguish different samples of river sediments.
School of Biomedical & Health Sciences, Pharmaceutical Science Division, King's College London, London, UK. ralph.menzel@biologie.hu-berlin.de
Ralph
R
Menzel
Suresh C
SC
Swain
Sebastian
S
Hoess
Evelyn
E
Claus
Stefanie
S
Menzel
Christian Ew
CE
Steinberg
Georg
G
Reifferscheid
Stephen R
SR
Stürzenbaum
D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects / Q000235:genetics*; D016000:Cluster Analysis; D020552:Comet Assay; D052244:Endocrine Disruptors / Q000633:toxicity; D004784:Environmental Monitoring; D015870:Gene Expression; D020869:Gene Expression Profiling; D019015:Geologic Sediments / Q000737:chemistry*; D005858:Germany; D019216:Metals, Heavy / Q000633:toxicity; D046228:Microarray Analysis; D020411:Oligonucleotide Array Sequence Analysis; D010865:Pilot Projects; D018510:RNA, Helminth / Q000235:genetics; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D052244:Endocrine Disruptors; D019216:Metals, Heavy; D018510:RNA, Helminth; D014874:Water Pollutants, Chemical