The genes coding for the biotin biosynthetic enzymes, bioABFCD are located at 17 min of the linkage map of EL coli K12 (Bachman, et al. Bact. Rev. 40: 116, 1976). It was shown that the bioA gene is oriented anticlockwise and the bioBFCD genes are oriented clockwise in the EL coli map, with the bio regulator region lying in between them (Guha et al. J. Mol. Biol. 56: 53, 1971). The study of the control elements of this divergently oriented operon at the molecular level is important for understanding the various intriguing mechanisms of gene expression in bacteria. In the present work, the electron microscopic characterization of the entire biotin genes and its regulator segment isolated after cleaving a biotin transducing phage DNA by restriction endonucleases, is described. The isolated biotin DNA fratments were subsequently recombined with the colEI DNA to isolate a colEl-biotin DNA hybrid. The present report also includes a portion of the study of this cloned plasmid chimera in a biotin auxotroph.
Characterization of Juvenile Hormone Biosynthetic Enzymes in the Mosquito, Aedes aegypti
