Bacterial Conjugation and Extrachromosomal Elements

Characterization of a Nosocomially Significant, Multiple Drug-Resistant Strain of <i>Serratia marcescen</i><i>s</i>

“…Based on these findings, we tentatively assume that this unusual strain of S. marcescens carries a nontransferable nonmobilizeable R-plasmid [1,10,11,13,26,32] with r-determinants against 10, if not 11 antimicrobial drugs, i.e. ampicillin, carbenicillin, chloramphenicol, gen tamicin, kanamycin, neomycin, streptomycin, tobramycin, triple sulfon amides, cotrimoxazole, and possibly nalidixic acid.…”

Extrachromosomal inheritance in bacteria.

“…Table 4 is a compilation of various extrachromosomal elements that conform generally to the patterns of plasmid organization as described above. Their general properties have been described repeatedly and at length in several excellent reviews (31,71,172,217,230). Present purposes will be served by a compact summary, including Table 4, which will be found useful for 217 VOL.…”

“…Some writers (98, 132) use the term plasmid to refer to extrachromosomal elements that are incapable of being integrated into the host chromosome. This usage is undesirable because of the operational problem of proving that a given element is incapable of integration and because it gives rise to such semantic whimsies as "one man's episome is another man's plasmid" (71). Furthermore, Lederberg, who first used the word, suggested it as a generic term for all extrachromosomal hereditary units (151).…”

Direct transfer of cloned genes from bacteria to mammalian cells.

“…In bacteria there exist various mechanisms for gene exchange among closely related species (for review see ref. 2). Gene transfer between unrelated species, or even between prokaryotes and eukaryotes, is rarely observed.…”