Conjugal fertility associated with resistance factor R in Escherichia coli.

Sugino, Yoshinobu (Osaka University, Osaka, Japan) and Yukinori Hirota. Conjugal fertility associated with resistance factor R in Escherichia coli. J. Bacteriol. 84:902-910. 1962.-The introduction of the contagious drug-resistance factor, R, into an F(-) strain of Escherichia coli allows the R(+)F(-) strain to mate with F(-)R(-) strains. The chromosome fragment transferred from the R(+) cell is relatively large, comparable to the conjugation between F(+) or Hfr male and F(-) female bacteria. The complex R factor has been analyzed by transduction with phage Pl. Within the R factor, the fertility determinant is inseparable from the determinant responsible for its infectivity, but can be separated from the loci for drug resistance. R thus resembles the category of complex F factors (F-primes) previously analyzed.