title: Temperature sensitive R plasmids isolated from Proteus strains.
abstract: Out of 32 R plasmids isolated from Proteus strains, 17 were found to be temperature sensitive with respect to inheritance in E. coli cells. They were fi- and classified into incompatibility group T or V. Cells carrying T group Rms273 plasmid were temperature sensitive with respect to growth and conjugal transfer in both E. coli and Proteus. The V group YOR-10 plasmid was stable in Proteus even at 42 C. However, the loss frequency of YOR-10 plasmid in E. coli reached 100% after 4 hr of incubation at 42 C, in spite of stable inheritance at 25 C. Conjugal transfer of the YOR-10 plasmid in E. coli was also strongly inhibited at 42 C. It has been concluded that instability of V group R plasmids in E. coli is due to their thermosensitive inheritance in the progeny cells at high temperatures.
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development; D006801:Humans; D010957:Plasmids; D011511:Proteus / Q000235:genetics*; D011513:Proteus mirabilis / Q000235:genetics / Q000254:growth & development; D013696:Temperature