The Way Ahead - Environmental Biotechnology: Theory and Application - page 274

likely to be confined to the laboratory or 'field' test kits, and so are unlikely to
warrant concern with regard to creating their own environmental pollution.
It has already been noted that GMOs are unlikely to occupy a significant niche
in bioremediation, principally due to the high cost in developing such organisms
set against the low financial return on remediation. Where they are likely to be of
great benefit is in solving problems for which no cheaper or simpler alternative
technology is available; examples of these are not widespread.
However, genetic engineering does, and will continue to, find a role in clean
technology as in examples quoted in Chapter 10. There is great potential to
develop 'designer biocatalysts', either as isolated enzymes, or as whole cells,
which should go a long way to helping industry improve its profitability and
environmental profile (Burton, Cowan and Woodley 2002). The picture is also
somewhat different where environmental biotechnology strays into agribiotech-
nology. Here the potential for the development of genetically modified plants
with improved quality or increased resistance to harsh conditions or pathogens,
as described in Chapters 9 and 10, is apparent.
Concerns about the safety of such constructs should be viewed in the light
of discussions in Chapter 3 emphasising the natural mobility of genetic mate-
rial. In nature, there is a considerable amount of genetic exchange even between
unrelated organisms. A powerful example is that of the insertion of the Ti plas-
mid of the bacterium, Agrobacterium tumefaciens, into plant cells and another is
the 'mariner' gene shown to have 'jumped ' from tsetse fly to human (Edwards
2000). A criticism frequently levied at genetic engineering is that it crosses
species boundaries, thereby transferring genes into organisms which could never
be recipients. An appreciation of the potential degree of genetic rearrangement
and exchange through the activities of plasmids, viruses and transposable ele-
ments leads to the conclusion that genetic engineering can be viewed as a very
tiny part of the overall picture. Furthermore, considering that there is an argument
suggesting a blurring between genomic and extrachromosomal genes, it seems
unrealistic to describe any gene as truly 'foreign' when the genome is proba-
bly carrying an array of genetic material originating from a variety of sources.
Generally, public alarm comes with the widespread release of large numbers of
specially engineered organisms into the environment, carrying genes which may
be envisaged causing an environmental problem greater than the one they seek to
solve. Such examples would be GM plants carrying genes for increased herbicide
or pesticide resistance.
In Chapters 9 and 10, reference was made to baculoviruses being used as
insecticides. There are many reasons why this appears to be a relatively safe
agent given that these nuclear polyhedrosis viruses (NPVs) are unable to infect
plants, microorganisms, vertebrates, or nonarthropod invertebrates. Assuming that
this argument is not invalidated by alteration to the host range, recombinant
baculoviruses should be even safer, since normally the protective polyhedrin
protein gene has been sacrificed in favour of the 'foreign' gene. This lack of