During the first of three planned
experiments at the Oxford University field station near Wytham Woods, it became
clear that some caterpillars had been killed by an unmodified NPV virus, which
should not have been present. This was clearly visible as the engineered virus
is designed to paralyse the caterpillars with the scorpion toxin quickly,
leaving the corpses intact. Infection with the wild virus proceeds until the
caterpillar deliquesces into a dark, virus-rich treacle. The presence of the
wrong kind of corpse in the experimental plots, indicated that the engineered
virus had become contaminated with its wild parent.
With the virus contaminated in this way, any experiment
designed to compare the two viruses would no longer be scientifically valid. And
it is now too late in the year to prepare enough fresh virus for a repeat
experiment this season.
News of the IoV’s problems was made public on Radio 4’s
Farming Today on 1 September by Dr George McGavin, assistant curator of
entomology at the Oxford University museum and a fierce critic of the experiment
on safety and environment grounds. He declined to name his sources, in which he
was entirely confident.
Several contamination sources were possible, he suggested.
The most likely was human error in the laboratory: less likely was the reversion
of the engineered virus back to its original form over successive generations.
The latter could impair the virus’ suitability for development into a
commercial insecticide.
But the commercial potential of the virus is already under
question, following the publication in Nature (14 July 1994) of findings from a
similar experiment performed last year. The engineered virus worked, but it
killed the target caterpillar only 10-15% quicker than the wild virus, and it
reduced their consumption of cabbage leaves by just 23-29%. These are hardly the
kind of results that will get farmers excited.
As for next year’s experiments, the IoV will have a far
harder time getting their proposal past the Department of the Environment’s
Advisory Committee on Releases to the Environment (ACRE) which advises the
Environment Secretary on whether or not to permit a release. Senior members of
ACRE are understood to be questioning the need to release the virus in an open
air location (though enclosed in fine nets), when entirely adequate contained
facilities exist at nearby Ascot in Berkshire. Adding to ACRE’s unease is the
virus’s unusually broad host range, which includes many wild British species.
David Bishop, IoV's Director, declined to comment on this
year’s experiments in advance of the publication of peer-reviewed scientific
journals.
New Biotech Information Sources
Two new sources of information on biotechnology developments are available.
The Splice of Life is a monthly newsletter covering developments in genetic engineering and biotechnology. Produced by the Genetic Forum, it also includes the activities of the Patent Concern coalition group. Details from 5-11 Worship Street, London EC2A 2BH.
GenEthics News, a bimonthly
newsletter on genetic engineering, ethics and the environment is published
by David King. The first issue contains articles on patents on life, BST,
food labelling, and the deliberate release of genetically engineered
rapeseed. It also lists details of releases of genetically engineered
organisms on the DoE’s register. Subscription details from PO Box 6313,
London N16 0DY.
[This article first appeared in Pesticides News No. 25, September 1994, page 21]