In feeding experiments we investigate uptake, distribution and expression of foreign DNA in rats. The research project focuses on whether sequences from DNA constructs used to make transgenic plants or transgenic sequences from Bt-transgenic sweet maize are taken up and have biological effects. In addition we investigate whether the authentic Bt toxin that is expressed in transgenic maize has biological effects. The use of antibiotic resistance genes as markers of genetic transformation in GMOs has put forward the question whether an antibiotic resistance gene may transform alimentary tract bacteria in vivo. In the feeding experiments we are also investigating if intestinal bacteria are able to pick up, stabilize and express resistance genes released from GMOs in the digestive tract. Furthermore we study whether the 35S cauliflower mosaic virus (CaMV)promoter used in GM plants) is active in mammalian cells.