Mischkolonien auxotropher und Wildtypzellen nach Behandlung von Esdierichia coli-Zellen mit salpetriger Säure

Abstract

Cells of E. coli incubated in HNO2 gave rise to unchanged wild-type colonies, colonies composed of wild-type and auxotrophic cells and colonies consisting of auxotrophic cells only. The mixed colonies are thought to originate from single cells, each harboring hybrid desoxyribonucleic acid with one subunit, probably a sister strand, changed by deamination of a cytosine or adenine, the other one with unchanged wild-type composition. In cells producing type 3 colonies this wild-type strand is mutated lethally by a separate deamination of cytosine or adenine. A mathematical treatment of this hypothesis leads to predictions which are in good agreement with experimental evidence. The data obtained are used for an estimation of the number of gene loci of E. coli.