Escherichia coli K-12 Mutants Resistant to Nalidixic Acid: Genetic Mapping and Dominance Studies1
AUTOR(ES)
Hane, Michael W.
RESUMO
Escherichia coli K-12 strains tested so far (approximately 20) can be separated into three groups on the basis of their abilities to form colonies on nutrient agar supplemented with nalidixic acid (NAL): (i) Nals or wild type (no growth at 1 to 2 μg/ml); (ii) NalAr (growth at 40 μg/ml or higher); and (iii) NalBr (growth at 4 μg/ml, but no growth at 10 μg/ml). The NalAr group has a spectrum of sensitivity ranging from 60 to over 100 μg/ml. All Hfr strains of the NalAr and NalBr groups transfer NAL resistance to recipient cells at genetic loci which are at 42.5 ± 0.5 and 51 ± 1 min, respectively, on the Taylor-Trotter map. Some members of the NalAr group also have the genetic locus for NalBr. The nalAs allele is completely dominant to nalAr in a partial diploid configuration. In haploids, nalAr-nalBr is phenotypically NalAr; nalAr-nalBs is NalAr; and nalAs-nalBr is NalBr. The map location of nalA and the easy differentiation between NalAr and NalAs allow this marker to be used as a counterselector in bacterial conjugation experiments.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=249993Documentos Relacionados
- Isolation, genetic mapping, and characterization of Escherichia coli K-12 mutants lacking gamma-glutamyltranspeptidase.
- Genetic Studies on Ribose 5-Phosphate Isomerase Mutants of Escherichia coli K-12
- Some Effects of Nalidixic Acid on Conjugation in Escherichia coli K-12
- Some Effects of Nalidixic Acid on Conjugation in Escherichia coli K-12
- Selection and characterization of beta-lactam-resistant Escherichia coli K-12 mutants.
