Fives-Taylor P, Novotny C P
J Bacteriol. 1974 Apr;118(1):175-9. doi: 10.1128/jb.118.1.175-179.1974.
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.
通过电子显微镜研究了胸腺嘧啶 - 5 - 溴尿嘧啶取代对大肠杆菌F(+)Lac(+)/Lac(-)Thy(-)菌株产生的F菌毛再生和长度的影响。当5 - 溴尿嘧啶（5BU）掺入脱氧核糖核酸（DNA）达到最大值时，菌毛的模态长度加倍，每个细胞的菌毛数量约为胸腺嘧啶培养细胞的50%。5BU培养的细胞形成交配对以及被核糖核酸（R17）和脱氧核糖核酸（M13）雄性特异性噬菌体感染的能力也降低了约50%。功能丧失并非由于性因子的丧失，因为5BU细胞保留了对吖啶橙敏感的性因子。5BU培养细胞上菌毛的伸长比胸腺嘧啶培养细胞对253.7nm的辐射更敏感，这表明DNA是敏感靶点。
