A site-specific DNA inversion in Bacteroides plasmid pBF4 is influenced by the presence of the conjugal tetracycline resistance element

DNA rearrangements and phenotypic switching in prokaryotes

Microorganisms have numerous strategies for coping with environmental changes. In many systems, a single cell has the capacity to generate a seemingly infinite array of phenotypic variants in just a few generations of growth. The resulting heterogeneous population is well equipped for sudden environmental change; even if only a few cells in the population possess a phenotype needed for survival, these cells have the capacity to regenerate a similarly diverse population. Phenotypic switching in these systems usually results from high-frequency DNA rearrangements which are the subject of this review.

Transfer of conjugal elements in oral black-pigmented Bacteroides (Prevotella) spp. involves DNA rearrangements

Conjugal genetic elements in isolates of oral black-pigmented Bacteroides denticola (Prevotella denticola) and B. intermedius (P. intermedia) transfer tetracycline and penicillin resistance in the absence of plasmids. Transverse alternating-field electrophoresis of restricted chromosomal DNAs from transconjugants revealed arrangements indicating that transfer and insertion can involve more than one 60-kb copy of the elements and occurs at strongly preferred sites in the recipient chromosome.