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Earthworm detectives provide genetic clues for dealing with soil pollution

3 June 2008

Earthworms are proving to be great detectives when it comes to identifying pollutants present in soil. They're helping scientists build up a detailed picture of how toxic chemicals and metals interact with living organisms by demonstrating the effects of toxins on genes.

Researchers from Cardiff and Edinburgh Universities, Imperial College London and the Centre for Ecology & Hydrology (CEH) used a systems toxicology approach to understand the impact of four contaminants on the earthworms (Lumbricus rubellus). Their findings are published today in two complementary research papers in BioMed Central's open access journals BMC Biology and BMC Genomics.

Lumbricus rubellus, the earthworm

Dr Peter Kille from Cardiff University who led the research team said, "The earthworm is widely used as a model organism for soil testing but standard laboratory tests do not reveal how pollutants behave in the genomic system, and how it adapts to deal with it. Although the earthworm genome has not been sequenced, we've been able to create a comprehensive expressed sequence tag dataset, that enables the development of tools that bring the earthworm into the genomics arena, and makes it the soil pollution equivalent of a canary in a coalmine."

Using a new 8,000-element gene microarray (an analysis system that allows the measurement of thousands of genes using a single sample) the researchers tested the effects of copper, cadmium, the poly-aromatic hydrocarbon fluoranthene, and the agrochemical atrazine.

The tests revealed subtle changes in the worms' genetic expression patterns, which are induced by the toxins. The effects of copper exposure, in particular, identified genetic and metabolic changes as well as massive deterioration in the worms' physical health.

Dr Kille said, "The research helps us to understand how, over millions of years, the earthworm has evolved adaptive mechanisms for dealing with soil pollution through genetically programmed responses. It also provides important clues to how humans will react or adapt to chemical exposure, as we share some common gene pathways with earthworms."

This multidisciplinary research combined a systems toxicology approach with technologies usually used in isolation. The result is a powerful tool for understanding how ecologically important organisms like the earthworm respond to contaminants and also opens up the possibility of new, more effective, soil monitoring and bioremediation strategies.

The research was funded by the Natural Environment Research Council through its Environmental Genomics thematic programme.

Further information

Vicky Dando
Cardiff University
Tel: 029 2087 9074

NERC Press Office
Natural Environment Research Council
Polaris House, North Star Avenue
Swindon, SN2 1EU
Tel: 01793 411561
Mob: 07917 557215

Notes

1. 'Systems toxicology approach identifies coordinated metabolic responses to copper in a terrestrial non-model invertebrate, the earthworm Lumbricus rubellus' is published in BMC Biology.
Authors: Drs Jacob G Bundy, Jasmin K Sidhu and Faisal Rana - Imperial College London, Drs David J Spurgeon and Claus Svendsen - Centre for Ecology & Hydrology, Dr Stephen Sturzenbaum, Cardiff University (now at Kings College London) and Drs Jodie F Wren, A John Morgan and Peter Kille - Cardiff University.

2. 'Transcriptome profiling of developmental and xenobiotic responses in a keystone soil animal, the oligochaete annelid Lumbricus rubellus' is published in BMC Genomics.
Authors: Dr Anne Hedley and Professor M L Blaxter - University of Edinburgh, Drs Matias J Jonker, Peter K Hankard, Linsey J Lister, Claus Svendsen and David J Spurgeon - Centre for Ecology & Hydrology, Dr Stephen Sturzenbaum, Cardiff University (now at Kings College London) and Drs Jodie F Wren, Jennifer Owen, A John Morgan and Peter Kille - Cardiff University.
The papers can be accessed through BioMed Central.

3. The comprehensive expressed sequence tag dataset can be accessed at www.earthworms.org.

4. The Natural Environment Research Council (NERC) funds world-class science, in universities and its own research centres, that increases knowledge and understanding of the natural world. It is tackling major environmental issues such as climate change, biodiversity and natural hazards. NERC receives around £400m a year from the government's science budget, which is used to provide independent research and training in the environmental sciences.

5. Biomed Central is an independent online publishing house committed to providing immediate access without charge to the peer-reviewed biological and medical research it publishes. This commitment is based on the view that open access to research is essential to the rapid and efficient communication of science.

Press release: 29/08