Marker rescue studies of the transfer of recombinant DNA to XXXX in vitro, in foods and gnotobiotic @entity35 .

@entity35 @entity415 @entity70929 @entity9190
A plasmid marker rescue system based on restoration of the nptII gene was established in @entity9190 to study the transfer of bacterial and transgenic plant DNA by transformation. In vitro studies revealed that the marker rescue efficiency depends on the type of donor DNA. Plasmid and chromosomal DNA of bacteria as well as DNA of transgenic @entity415 were transferred with efficiencies ranging from 8.1 x 10(-6) to 5.8 x 10(-7) transformants per nptII gene. Using a 792-bp amplification product of nptII the efficiency was strongly decreased (9.8 x 10(-9)). In blood sausage, marker rescue using plasmid DNA was detectable (7.9 x 10(-10)), whereas in milk @entity70929 ( @entity70929 ) had to be added to obtain an efficiency of 2.7 x 10(-11). No marker rescue was detected in extracts of transgenic @entity415 despite addition of @entity70929 . In vivo transformation of @entity9190 LTH 5597 was studied in monoassociated @entity35 by using plasmid DNA. No marker rescue could be detected in vivo, although transformation was detected in the presence of saliva and fecal samples supplemented with @entity70929 . It was also shown that plasmid DNA persists in @entity35 saliva permitting transformation for up to 6 h of incubation. It is suggested that the lack of marker rescue is due to the absence of competence-stimulating factors such as serum proteins in @entity35 saliva.
