Segregation of the mutator property of plasmid R46 from its ultraviolet-protecting property
Creators
- 1. Stanford Univ., CA (USA). Dept. of Medical Microbiology
Description
Plasmid R46 (an R factor conferring resistance to ampicillin, sulfonamides, streptomycin and tetracycline) reduces the bactericidal effect of UV irradiation but increases it mutagenic effect (reversion of hisG46), and raises the frequency of spontaneous reversion (mutator effect). Putative deletion mutants of R46 were obtained by transduction of the plasmid, then two successive conjugal transfers. Plasmids of five of six deletion classes, each with a different combination of drug resistance traits, retained conjugative ability and the UV-protecting, mutagenesis-enhancing and mutator effects of R46. (pKM101, used in the Ames system to enhance responsiveness to chemical mutagens, is one such mutant of R46.) Plasmids of a sixth class, represented by pKM115, conferred resistance only to streptomycin and were non-conjugative. All of several such plasmids (of independent origin) had a much stronger mutator effect than did R46, but lacked UV-protecting ability and did not enhance the mutagenic effect of UV irradiation. (orig./AJ)
Abstract (German)
Plasmid R46 (ein R-Faktor, der Ampicillin, Sulfonamiden, Streptomycin und Tetracyclin Resistenz verleiht), reduziert die bakterizide Wirkung von UV-Bestrahlung, doch verstaerkt deren mutagene Wirkung (Reversion von hisG46) und erhoeht die Haeufigkeit spontaner Reversionen (Mutator-Effekt). Wahrscheinliche Tilgungsmutanten von R46 wurden durch Transduktion des Plasmids und nachfolgend zwei aufeinanderfolgende konjugale Transfers erzeugt. Plasmide aus fuenf von sechs Deletionsgruppen, jede mit einer verschiedenen Kombination von Arzneimittelresistenzmerkmalen, behielten ihre konjugativen Faehigkeiten und die von UV schuetzenden, Mutagenese verhindernden und Mutator-Effekte von R46. (pKM101, das im Ames-System verwandt wird zur Erhoehung der Empfaenglichkeit gegenueber chemischen Mutagenen, ist ein solcher Mutant von R46). Plasmide einer sechsten Gruppe, repraesentiert durch pKM115, verliehen lediglich Streptomycin Resistenz und waren nicht konjugativ. Alle aus einer Vielzahl solcher Plasmide (verschiedenen Ursprungs) hatten einen viel staerkeren Mutator-Effekt als R46, wiesen jedoch keine vor UV-schuetzenden Eigenschaften auf und erhoehten den mutagenen Effekt von UV-Bestrahlung nicht. (orig./AJ)Additional details
Publishing Information
- Journal Title
- Mol. Gen. Genet.
- Journal Volume
- 167
- Journal Issue
- 3
- Series
- Mol. Gen. Genet.
- Journal Page Range
- 317-327
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 10452104
- Subject category
- S63: RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS;
- Descriptors DEI
- DNA; ESCHERICHIA COLI; GENETIC RADIATION EFFECTS; LETHAL IRRADIATION; MUTAGENESIS; MUTAGENS; MUTATIONS; RADIATION INDUCED MUTANTS; RADIATION PROTECTION; RESPONSE MODIFYING FACTORS; SALMONELLA TYPHIMURIUM; ULTRAVIOLET RADIATION
- Descriptors DEC
- BACTERIA; BIOLOGICAL EFFECTS; BIOLOGICAL RADIATION EFFECTS; ELECTROMAGNETIC RADIATION; GENETIC EFFECTS; IRRADIATION; MICROORGANISMS; MUTANTS; NUCLEIC ACIDS; ORGANIC COMPOUNDS; RADIATION EFFECTS; RADIATIONS; SALMONELLA