title: Replication of the R factor Rts1 in Proteus mirabilis.
abstract: The replication of the R factor Rts1 in Proteus mirabilis was examined by using the technique of CsCl density-gradient centrifugation. The proportion of Rts1 deoxyribonucleic acid (DNA) relative to the host chromosomal DNA (% R-DNA) was 7% in both exponential and stationary growth phases in Penassay Broth and supplemented M9 minimal medium at 30 C. The chromosomal DNA content per cell varied over a threefold range in the different growth media. In agreement with previous genetic observations, the replication of Rts1 was found to be temperature-sensitive and Rts1 DNA was diluted from the cells during exponential growth at 42 C. (14)N-(15)N medium transfer experiments have shown that individual copies of Rts1 are selected at random for replication during the duplication of the multicopy episome pool.
mesh_terms: D000643:Ammonium Chloride; D002455:Cell Division; D002499:Centrifugation, Density Gradient; D002586:Cesium; D002712:Chlorides; D002876:Chromosomes, Bacterial / Q000032:analysis*; D003470:Culture Media; D004261:DNA Replication; D004269:DNA, Bacterial / Q000032:analysis* / Q000096:biosynthesis / Q000302:isolation & purification; D003720:Densitometry; D004352:Drug Resistance, Microbial; D007612:Kanamycin / Q000494:pharmacology; D009587:Nitrogen Isotopes; D011511:Proteus / Q000254:growth & development*; D011513:Proteus mirabilis / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
chemical_list: D002712:Chlorides; D003470:Culture Media; D004269:DNA, Bacterial; D009587:Nitrogen Isotopes; D000643:Ammonium Chloride; D002586:Cesium; D007612:Kanamycin