This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Fives-Taylor, P. Articles by Novotny, C. P. Search for Related Content PubMed PubMed Citation Articles by Fives-Taylor, P. Articles by Novotny, C. P.

Effect of Thymine-5-Bromouracil Substitution on F Pili

¹ Department of Medical Microbiology, The University of Vermont College of Medicine, Burlington, Vermont 05401

ABSTRACT

The effect of thymine-5-bromouracil substitution on the regeneration and length of F pili produced by an F⁺Lac⁺/Lac^–Thy^– strain of Escherichia coli was studied by electron microscopy. When 5-bromouracil (5BU) incorporation into deoxyribonucleic acid (DNA) was maximal, the modal length of the pilus doubled and the number of pili per cell was approximately 50% that of thymine-grown cells. The ability of 5BU-grown cells to form mating pairs and to be infected by ribonucleic acid (R17) and DNA (M13) male-specific phages was also reduced by approximately 50%. Loss of function was not due to loss of sex factor as 5BU cells retained a sex factor that was susceptible to curing by acridine orange. Elongation of pili on 5BU-grown cells was more sensitive to irradiation at 253.7 nm than on thymine-grown cells, suggesting that DNA is the sensitive target.