A primitive worm could help to screen new medicines, according to research.
The worm wriggles away from certain chemicals
Scientists have genetically modified nematode worms (C. elegans) so they avoid and crawl away from certain chemicals.
The UK/Dutch team believes the worms could help to provide a simple method for looking at the effectiveness of compounds for new drugs.
The research is published in the journal Biomedcentral Biology.
Nematode worms are less than 1mm long and live in the soil feeding on bacteria.
Through receptors in their nerves, they can detect and avoid harmful chemicals in their environment.
Scientists from the Wellcome Trust Sanger Institute, UK, and the Erasmus Medical Centre, the Netherlands, modified the worms to contain human receptors.
Drugs are often designed to bind to receptors, to either block or activate them, so detecting whether a potential medicine interacts with the receptor is key.
In this case, they introduced the somatostatin receptor, which is activated by a hormone called somostatin that is important in neural signalling.
They also modified some worms to have the chemokine receptor 5, which responds to a molecule called chemokine that plays an important role in the immune system.
The scientists found that when somostatin or chemokine were placed in the pathway of the modified worms, they detected the chemicals and crawled away from them.
Dr John McCafferty, an author on the paper and a principal investigator at the Sanger Institute, said: "To survive, the worms have to taste and smell the environment around them, and they will automatically swim towards food and away from harmful chemicals.
"We basically hijacked that system to make them respond to human signalling molecules, and effectively they are tasting the human signalling molecules and swimming away from them."
He said in the future the worms could be modified to carry a range of different human receptors that scientists are targeting for new drugs.
He said: "This makes it a very simple response that which we can measure, and therefore provides a way to look for new molecules or substances or drugs which act on the human receptor of interest."
He added that many of the current methods for screening compounds use tissue culture, but this can be expensive and needs very purified compounds.
But this new method, he said, would be cheap, fast and easy to use. Professor Mark Blaxter, from the Institute of Evolutionary Biology, said: "This is a very nice piece of work that really exploits the C. elegans system.
"The lovely thing about C. elegans is that it has a very simple body plan.
"It has 959 cells as an adult female, and 302 of those are neurons. Compared to us where we have billions of neurons, it is a wonderfully simple nervous system and yet it does very complicated behaviour.
"Forty years ago Sidney Brenner, who has a Nobel Prize for this, said that this worm was going to be useful for medical research. One of the reasons he wanted to work on it was because of the nervous system.
"And it is really quite nice that this lab has turned the worm into a test-bed for the human nervous system."