title: Single-strand regions in the deoxyribonucleic acid of competent Haemophilus influenzae.
abstract: The deoxyribonucleic acid (DNA) of competent wild-type Haemophilus influenzae and rec1 mutant cells contains single-strand regions, as judged by alkaline sucrose sedimentation, benzoylated naphthoylated diethylaminoethyl-cellulose fractionation, and digestion with an enzyme specific for single-strand regions in DNA. In contrast, the DNA of competent rec2 cells does not contain single-strand regions. Since transforming DNA does not associate with recipient DNA in the rec2 mutant as it does in wild type and rec1, it is concluded that the single-strand regions in the DNA of the competent cells are important for an early step in recombination between cell DNA and transforming DNA.
mesh_terms: D001973:Bromodeoxyuridine / Q000378:metabolism; D002250:Carbon Radioisotopes; D002499:Centrifugation, Density Gradient; D002848:Chromatography, DEAE-Cellulose; D004269:DNA, Bacterial / Q000032:analysis* / Q000096:biosynthesis; D004277:DNA, Single-Stranded / Q000032:analysis*; D003851:Deoxyribonucleases / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism; D006193:Haemophilus influenzae / Q000032:analysis* / Q000378:metabolism; D008970:Molecular Weight; D009154:Mutation; D009691:Nucleic Acid Denaturation; D011995:Recombination, Genetic; D013936:Thymidine / Q000378:metabolism; D014170:Transformation, Genetic; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D004269:DNA, Bacterial; D004277:DNA, Single-Stranded; D014316:Tritium; D003851:Deoxyribonucleases; D004720:Endonucleases; D001973:Bromodeoxyuridine; D013936:Thymidine