MICROBIAN GENETICS: REVERSIBLE INTEGRATION OF THE F' SEX EPISOME IN ESCHERICHIA COLI K 12
Abstract
Some clones, Hfr, were selected, either at high temperature or at low temperature in the presence of acridine on the basis of mutated bacteria whose F' episome does not multiply at high temperature in the autonomous state. The integration mechanisms of the episome and of the chromosomal transfer by I strains may be deduced from the properties of these strains. The sex episome of Escherichia coli K 12, in the autonomous state, confers on the bacterium that carries it (F+) the capability of being paired with a bacterium F- and of transferring episome F to it at high frequency. The integration of the episome and of the chromosome creates a new type of male bacterium (Hfr), which transfers an oriented group of chromosomal genes at high frequency, but does not transfer the autonomous episome F. A third sexual type, intermediary type (I), has also been observed recently. The I bacteria transfer the episome by crossing the autonomous state with the same efficacy as the F+ bacteria. Like the Hfr bacteria, on the other hand, but with a ten times lower frequency, they transfer a characteristic chromosomal sequence. All these characteristics are acquired simultaneously by the bacteria that receive the episome of an I bacteria (modified episome F') by conjugation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1963
- Accession Number
- AD0836718
Entities
People
- Francois Cuzin
- Francois Jacob
Organizations
- United States Army Biological Warfare Laboratories