Acute and repeated dose (28 day) mouse oral toxicology studies with Cry34Ab1 and Cry35Ab1 Bt proteins used in coleopteran resistant DAS-59122-7 corn.
Expression of the Cry34Ab1 and Cry35Ab1 proteins from Bacillus thuringiensis (Bt) Berliner strain PS149B1 in genetically modified maize (event DAS-59122-7) protects the crop from damage due to feeding by Diabrotica larvae including the western corn rootworm (Diabrotica virgifera virgifera). As part of the safety assessment of this maize, mammalian toxicology studies were conducted with heterologously produced Cry34Ab1 and Cry35Ab1 proteins. No evidence of acute toxicity was observed in mice following oral exposure to either the Cry34Ab1 or Cry35Ab1 proteins individually (2700 and 1850 mg/kg, respectively) or concomitantly (482 and 1520 mg/kg, respectively; 1:1 molar ratio). Similarly, no adverse effects were observed in mice in a repeated dose (28 day) dietary toxicity study that incorporated these proteins into diets at concentrations corresponding up to 1000-fold greater than the highest estimate of human exposure based on the concentrations of these proteins expressed in 59122 maize grain. These studies demonstrate that the Cry34Ab1 and Cry35Ab1 proteins do not represent a risk to human health and support previous studies indicating that 59122 maize grain is as safe and wholesome as non-GM maize grain.
Juberg
Daland R
DR
Dow AgroSciences, LLC, Indianapolis, IN 46268, USA. drjuberg@dow.com
Herman
Rod A
RA
Thomas
Johnson
J
Brooks
Keith J
KJ
Delaney
Bryan
B