Molecular Genetics in Biotechnology, Toxicology and Conservation
Key staff: Dr Ivor Evans
Since Crick and Watson discovered the structure of DNA in 1953, molecular biology and molecular genetics have developed explosively, becoming the core life sciences. All life processes depend on information flow from the genes in DNA into the proteins that drive cell function. All aspects of the life sciences can therefore be illuminated by studies of genes and proteins. The development of gene cloning, sequencing and engineering techniques has permitted sequencing of entire genomes, including the yeast Saccharomyces cerevisiae, completed in 1996, and Homo sapiens in 2003.
At Greenwich we have used the techniques of molecular biology in several areas. In relation to food processing and ethanol production, we have purified and characterised enzymes that break down starch, and cloned and sequenced a gene for a dextranase, which hydrolyses a starch-like polysaccharide. We also use molecular biology to detect and study toxins, like the mycotoxins produced by fungi that contaminate the human food chain. We developed a colorimetric bioassay for trichothecene mycotoxins, which uses a yeast ßß-galactosidase enzyme to produce a colour-change signal of toxicity. We then used genetic engineering to refine this approach, using a cloned Penicillium dextranase gene expressed in Saccharomyces cerevisiae to produce a more sensitive, fluorimetrically detectable, signal of toxicity. We hope to understand how toxins work and, collaborating with University of Manchester Institute of Science and Technology, we have used DNA chips to see which genes are turned on and off when a toxin attacks a yeast cell – engineered to model a human cell.
In a different area of biology, we have used molecular genetics to show that a species of frog (Rana lessonae) that has just become extinct in Britain was native, not an introduction, and that its closest relatives live in Scandinavia. Working with conservation groups and ecologists in UK and Sweden, we have just reintroduced the species to a protected location in Norfolk, and are monitoring its progress.
We have received funding from bodies including the Biotechnology and Biological Sciences Research Council (BBSRC) and English Nature (now Natural England). We have also ollaborated with colleagues in the university’s Natural Resources Institute and with local industry to develop a soil toxicity tester (Safe Soil Tester) that uses a bioluminescent bacterium to signal toxicity. We are currently collaborating with the biotechnology company Genzyme to produce dextranase preparations on a large scale, by fermentation, in order to assess some health-care applications of the enzyme.