Contents - Faperta

448 Biotechnological Approaches for Pest Management and Ecological Sustainability
genetically modifi ed crops such as maize or soybean is equivalent to the conventional
nontransgenic crops as it does not include detectable protein or DNA derived from the
genetically modifi ed plant. Grain and forage of event MON 863 are comparable in their
nutritional content to the control maize hybrid and the conventional nontransgenic maize
(Berberich et al., 1996; George et al., 2004). These comparisons, together with the history of
the safe use of corn as a common component of animal feed and human food, support the
conclusion that corn event MON 863 is compositionally equivalent to, and as safe and
nutritious as, conventional corn hybrids grown commercially. Very little Bt toxins remain
in plant parts to be consumed by human beings or dairy cattle, for example, the raw seed
of line 81 (with the cryIAb gene) showed 14.00 μg per gram of active protein, while the line
531 (with the cryIAc gene) contained 2.22 μg per gram of active protein as detected by
ELISA (Berberich et al., 1996). Chemical analysis has not shown major changes in nutritional
composition of transgenic Bt tomatoes compared to that of the control lines. Moreover,
levels of the glycoalkaloid a-tomatine were similar to the parent variety. Preliminary analysis
of the results of a 91-day feeding trial of transgenic Bt tomatoes in rats did not reveal
any signs of adverse effects (Noteborn et al., 1995). Russet Burbank potato plants, which
resist damage by Colorado potato beetle, Leptinotarsa decemlineata (Say), produce two
additional proteins, the Bacillus thuringiensis subsp. tenebrionis protein and the neomycin
phosphotransferase II protein (Lavrik et al., 1995). The presence of these proteins and the
process used to produce these plants did not alter the quality, composition, or safety of the
tubers from insect-resistant plants as compared to commercial Russet Burbank potatoes.
Toxicological Effects and Metabolism of the Transgene Products
Safety evaluations include a detailed consideration of genetic modifi cation with respect to
both the DNA sequences that are introduced and the site of integration in the genome of
the recipient species. Phenotypic data and detailed chemical composition covering a wide
range of nutritionally important parameters are usually considered. Assessment is also
made of allergic potential arising from foreign DNA (transgenes) in genetically modifi ed
foods. If there are differences between the genetically modifi ed product and its conventional
counterpart, then further investigations are carried out. These may include toxicological
assessments of the introduced protein and animal feeding studies. In animal studies, any
changes in tissue structure or metabolic function of various organs (liver, kidney, lungs, brain,
and cardiovascular organs) should be assessed. In human studies, measures of general health,
development, and psychological well-being should be included in biosafety evaluations.
Biosafety of Transgene Products
Bt Cry Proteins
Based on published information, it has been concluded that Bt is safer to humans and other
nontarget organisms (McClintock, Schaffer, and Sjoblad, 1995; Siegel, 2001). There are no
specifi c receptors for Bt protein in the gastrointestinal tract of mammals, including man
(Kuiper and Noteborn, 1994). The toxin proteins produced by Bt are toxic to only a few
species of insects based on brush border membrane receptors and the structure of the
proteins. The species that lack the protein receptors tolerate Bt exposure without any injury.