scholarly journals Spontaneous mutation frequency and emergence of ciprofloxacin resistance in Campylobacter jejuni and Campylobacter coli

2007 ◽  
Vol 60 (6) ◽  
pp. 1251-1257 ◽  
Author(s):  
M.-L. Hanninen ◽  
M. Hannula
Keyword(s):  
Campylobacter Jejuni ◽  
Mutation Frequency ◽  
Spontaneous Mutation ◽  
Campylobacter Coli ◽  
Ciprofloxacin Resistance ◽  
Spontaneous Mutation Frequency

scholarly journals SPONTANEOUS UNSTABLE UNC-22 IV MUTATIONS IN C. ELEGANS VAR. BERGERAC

Genetics ◽  
1984 ◽  
Vol 108 (4) ◽  
pp. 859-877
Author(s):  
D G Moerman ◽  
R H Waterston
Keyword(s):  
Mutation Frequency ◽  
Spontaneous Mutation ◽  
Phenotypic Effect ◽  
C Elegans ◽  
High Mutation Frequency ◽  
Mutator Activity ◽  
Discrete Site ◽  
Unstable Mutations ◽  
Spontaneous Mutation Frequency ◽  
Forward Mutation

ABSTRACT This paper describes a mutator system in the nematode Caenorhabditis elegans var. Bergerac for the gene unc-22. Of nine C. elegans and two C. briggsae strains tested only the Bergerac BO strain yielded mutant animals at a high frequency and the unc-22 IV gene is a preferred mutational target. The forward spontaneous mutation frequency at the unc-22 locus in Bergerac BO is about 1 × 10-4, and most of these spontaneous unc-22 mutations revert at frequencies between 2 × 10-3 and 2 × 10-4. Both the forward mutation frequency and the reversion frequency are sensitive to genetic background. Spontaneous unc-22 mutations derived in a Bergerac background and placed in a primarily Bristol background revert at frequencies of <10-6. When reintroduced into a Bergerac/Bristol hybrid background the mutations once again become unstable. The mutator activity could not be localized to a discrete site in the Bergerac genome. Nor did mutator activity require the Bergerac unc-22 gene as a target since the Bristol unc-22 homolog placed in a Bergerac background also showed high mutation frequency. Intragenic mapping of two spontaneous unc-22 alleles, st136 and st137, place both mutations in the central region of the known unc-22 map. However, these mutations probably recombine with one another, suggesting that the unstable mutations can occur in more than one site in unc-22. Examination of the phenotypic effect of these mutations on muscle structure indicates that they are less severe in their effect than a known amber allele. We suggest that this mutator system is polygenic and dispersed over the nematode genome and could represent activity of the transposable element Tc1.

Disruption of Xpg increases spontaneous mutation frequency, particularly A:T to C:G transversion

2001 ◽  
Vol 487 (3-4) ◽  
pp. 127-135 ◽  
Author(s):  
Naoko Shiomi ◽  
Emiko Hayashi ◽  
Shun-ichi Sasanuma ◽  
Kazuei Mita ◽  
Tadahiro Shiomi
Keyword(s):  
Mutation Frequency ◽  
Spontaneous Mutation ◽  
Spontaneous Mutation Frequency

scholarly journals The mutagenicity of amino acid analogues inCoprinus lagopus

1974 ◽  
Vol 23 (1) ◽  
pp. 47-61 ◽  
Author(s):  
Philippa J. Talmud ◽  
D. Lewis
Keyword(s):  
Amino Acid ◽  
Mutation Frequency ◽  
Spontaneous Mutation ◽  
Base Change ◽  
Response Curves ◽  
Amino Acid Analogues ◽  
Single Base Change ◽  
Protein Incorporation ◽  
Dose Dependent ◽  
Spontaneous Mutation Frequency

SummaryThe amino acid analoguesp-fluorophenylalanine (PFP) and ethionine (ETH) are strongly mutagenic inCoprinus lagopus. The most pronounced effect was found with suppressor mutations of themet-1locus. PFP, at a concentration of 2·4 × 10−4M, increased the mutation frequency 500 fold and ETH, at a concentration of 2·4 × 10−3M, 30 fold over the spontaneous mutation frequency. From the spectrum of suppressors of themet-1locus and the dominant revertants of thead-82locus, induced by analogue treatments, it was concluded that both analogues induce single base-change mutations. The dose response curves follow a sigmoid plot, revealing that within a certain range of analogue concentrations, muta-genesis is strongly dose dependent.Using analogue resistant mutants, it has been shown that PFP mutagenesis is a function of its incorporation into protein. However, ETH mutagenesis is independent of protein incorporation but can be correlated with the degree of ethylation of nucleic acids. The synergistic effect PFP and ETH supports the evidence of the different mutagenic actions of the two analogues.

scholarly journals Spontaneous mutation frequency is elevated in skin of harlequin (hq)/Big Blue(R) mice

Mutagenesis ◽  
2010 ◽  
Vol 25 (3) ◽  
pp. 235-242 ◽  
Author(s):  
F. S. Van Osch ◽  
M. Piliguian ◽  
K. A. Hill
Keyword(s):  
Mutation Frequency ◽  
Spontaneous Mutation ◽  
Spontaneous Mutation Frequency
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