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Abstract
SUMMARY: The state of colicinogenic factors E2, I and V (col E2, col 1 and col V) In Escherichia coli K 12 studied. The analysis of the results of conjugation experiments involving different Hfr or F+ and F− strains shows that: (1) The frequency transfer of these colicinogenic factors differs markedly: col V is tr with maximum efficiency, col E2 and col I, on the contrarv, only at low frequency. (2) Each colicinogenic factor is transferred from different type of Hfr or F+ strains with similar frequencies. (3) They linked with chromosomal markers. (4) The non-colicinogenic character of the donor parent is never transmitted to recombinants. (5) Zygotes that have received col V, transmit it to all daughter cells. All these ults lead to the conclusion that colicinogenic factors E2 I and V are in an extrachromosomal state in F+ and Hfr bacteria. The same; would apply to their state in F− bacteria, since the results with inogenic factor V seem to indicate that this factor replicates in of bacteria autonomously and at a faster rate than the chromosome.
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