Exclusion in IncI-typeEscherichia coliconjugations: the stage of conjugation at which exclusion operates

✍ Scribed by R. A. Hartskeerl; W. P. M. Hoekstra

• Publisher: Springer Netherlands
• Year: 1984
• Tongue: English
• Weight: 613 KB
• Volume: 50
• Category: Article
• ISSN: 0003-6072
• DOI: 10.1007/bf00400171

✦ Synopsis

The stage at which exclusion operates in matings between donors belonging to the I-type incompatibility group (IncI) was investigated. Mating between Escherichia coli cells harbouring the I-type plasmid R144 and E. coli cells harbouring the R 144-derived recombinant plasmid p RAH308, which causes a hundredfold exclusion, was performed on a membrane filter to test whether mating aggregate formation was disturbed. Besides, level and kinetics of the formation of mating aggregates in mixtures of R144 + donor cells and recipient cells carrying plasmid pRAH308 (exclusion-proficient) was compared with the aggregate formation in mixtures of the donor cells and exclusion-deficient recipient cells. Results from these experiments revealed that the exclusion by pRAH308 does not operate at the level of aggregate formation, but acts at the stage of DNA transfer. The exclusion phenomenon by the recombinant plasmid pRAH308 appeared to be representative for exclusion caused by plasmid R 144, since essentially identical results were obtained if plasmid R144 was used as exclusiondetermining factor.