| Popis: |
On the basis of Bacillus subtilis DNA and vectors pBR325, pBR322, a collection of hybrid plasmids restoring the wild type in the double Escherichia coli mutant for thymidine phosphorylase (deoA) and uridine phosphorylase (udp) has been obtained. In spite of the fact that in Bac. subtilis, in contrast to E. coli, phosphorolytic cleavage of thymidine and uridine is catabolized by one enzyme-pyrimidine nucleoside phosphorylase (pdp gene), some plasmids caused the appearance of the activity similar to thymidine phosphorylase (deoA type) in E. coli cells. Plasmids of the deoA type as well as many of plasmids causing the appearance in E. coli cells of the activity of the pdp type were not able to transform cells of the Bac. subtilis pdp mutant, strain PC315, to the wild type. Moreover, on the basis of PC315 DNA, hybrid plasmids have been obtained giving the activity of the pdp type. The suggestion of the possible presence in Bac. subtilis 168 genome of non-expressible cryptic genes of the deoA and pdp type is discussed. |
