Hope Not Hype - Third World Network

68 Hope Not Hype
Bacillus producing δ-endotoxins encoded by cry and cyt genes are considered to be a
pathogen of insects rather than mammals (Appendix Three; NPTN, 2000; Schnepf et al.,
1998). The cry genes are named after the parasporal crystal proteins which form inclusions
in B. thuringiensis spores.
All pesticides have environmental costs. Insecticidal crops are toxic to both target
and non-target organisms. The full range of non-target effects of Bt crops is still to be
determined (Schmidt et al., 2008). As with research on yield, the amount of research on the
effects of insecticidal crops has been limited by the number of years since their
commercialization and the number and quality of studies.
[I]n the case of GM crops, scientific analyses have also been deficient. In particular, many
experiments used to test the environmental safety of GM crops were poorly replicated, were
of short duration, and/or assessed only a few of the possible response variables. Much could
be learned and perhaps some debates settled if there were credible quantitative analyses of
the numerous experiments that have contrasted the ecological impact of GM crops with those
of control treatments involving non-GM varieties (Marvier et al., 2007, p. 1475).
Important organisms in freshwater, where the residues of Bt crops are expected to
accumulate, are among the non-target organisms that have been found to be affected.
Laboratory feeding trials showed that consumption of Bt corn byproducts reduced growth
and increased mortality of nontarget stream insects. Stream insects are important prey for
aquatic and riparian predators, and widespread planting of Bt crops has unexpected ecosystemscale
consequences (Rosi-Marshall et al., 2007, p. 16204).
We conclude that the tested variety of Bt-maize and its UM [unmodified] counterpart do not
have the same quality as food sources for this widely used model organism. The combination
of a reduced fitness performance combined with earlier onset of reproduction of D. magna
fed Bt-maize indicates a toxic effect rather than a lower nutritional value of the GM-maize
(Bøhn et al., 2008, p. 584).
Human health effects of Bt crops are more uncertain. However, there are very few
studies on human consumption of GM crop plants and no studies on effects of inhalation;
even animal studies are rare (Domingo, 2007; Pryme and Lembcke, 2003). Worryingly,
some research as recent as late 2008 is warning of potential adverse effects (Appendix
Three; Finamore et al., 2008; Seralini et al., 2007; Velimirov et al., 2008).
Until now, assessment of GMO immune adverse effects was based on the potential allergenic
evaluation of the pure recombinant proteins, and only a recent study has considered the potential
immunotoxicological effects of whole GMO given to rats for different periods. In addition,
no studies have considered the intestinal immune response for such a purpose. However, the
intestine interacts continuously with food-derived antigens, allergens, pathogens, and other
noxious agents, and the gut immune system, which is the largest lymphoid tissue of the body,
is crucial for mounting a correct immune response while maintaining a quiescent status toward
innocuous antigens (Finamore et al., 2008, p. 11533).